Science And Technology

financial crisis

2009-04-30T12:32:00.000-07:00

The term financial crisis is applied broadly to a variety of situations in which some financial institutions or assets suddenly lose a large part of their value. In the 19th and early 20th centuries, many financial crises were associated with banking panics, and many recessions coincided with these panics. Other situations that are often called financial crises include stock market crashes and the bursting of other financial bubbles, currency crises, and sovereign defaults.[1][2]

Many economists have offered theories about how financial crises develop and how they could be prevented. There is little consensus, however, and financial crises are still a regular occurrence around the world.

jobs

2009-04-30T12:31:00.000-07:00

Jobs in Egypt helps you to find a job in Egypt, Jobs In Egypt provides you with the most comprehensive suite of career building tools available. By using Jobs in Egypt you will gain the knowledge necessary to succeed in employment marketplace. If you are Egyptian, resident inside or outside Egypt, or if you are not Egyptian but resident in Egypt like to find a job, build or change career then

Nanotechnology

2009-04-30T12:26:00.000-07:00

shortened to "Nanotech", is the study of the control of matter on an atomic and molecular scale. Generally nanotechnology deals with structures of the size 100 nanometers or smaller, and involves developing materials or devices within that size.

Nanotechnology is very diverse, ranging from novel extensions of conventional device physics, to completely new approaches based upon molecular self-assembly, to developing new materials with dimensions on the nanoscale, even to speculation on whether we can directly control matter on the atomic scale.

There has been much debate on the future of implications of nanotechnology. Nanotechnology has the potential to create many new materials and devices with wide-ranging applications, such as in medicine, electronics, and energy production. On the other hand, nanotechnology raises many of the same issues as with any introduction of new technology, including concerns about the toxicity and environmental impact of nanomaterials [1], and their potential effects on global economics, as well as speculation about various doomsday scenarios. These concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warranted.

The first use of the concepts in nanotechnology but pre-dating use of that name) was in "There's Plenty of Room at the Bottom," a talk given by physicist Richard Feynman at an American Physical Society meeting at Caltech on December 29, 1959. Feynman described a process by which the ability to manipulate individual atoms and molecules might be developed, using one set of precise tools to build and operate another proportionally smaller set, so on down to the needed scale. In the course of this, he noted, scaling issues would arise from the changing magnitude of various physical phenomena: gravity would become less important, surface tension and Van der Waals attraction would become more important, etc. This basic idea appears plausible, and exponential assembly enhances it with parallelism to produce a useful quantity of end products. The term "nanotechnology" was defined by Tokyo Science University Professor Norio Taniguchi in a 1974 paper[2] as follows: "'Nano-technology' mainly consists of the processing of, separation, consolidation, and deformation of materials by one atom or by one molecule." In the 1980s the basic idea of this definition was explored in much more depth by Dr. K. Eric Drexler, who promoted the technological significance of nano-scale phenomena and devices through speeches and the books Engines of Creation: The Coming Era of Nanotechnology (1986) and Nanosystems: Molecular Machinery, Manufacturing, and Computation,[3] and so the term acquired its current sense. Engines of Creation: The Coming Era of Nanotechnology is considered the first book on the topic of nanotechnology. Nanotechnology and nanoscience got started in the early 1980s with two major developments; the birth of cluster science and the invention of the scanning tunneling microscope (STM). This development led to the discovery of fullerenes in 1985 and carbon nanotubes a few years later. In another development, the synthesis and properties of semiconductor nanocrystals was studied; this led to a fast increasing number of metal oxide nanoparticles of quantum dots. The atomic force microscope was invented six years after the STM was invented. In 2000, the United States National Nanotechnology Initiative was founded to coordinate Federal nanotechnology research and development.

Bird flu

2009-04-30T10:13:00.000-07:00

Bird flu may refer to:

Biology and disease
Avian influenza, influenza endemic to birds.
Influenzavirus A, the causative agent for bird flu; the genus of the Orthomyxoviridae family. of viruses to which all viruses responsible for Avian influenza belongs to, but also includes viruses that are endemic to humans and other animals.
H5N1, a subtype of Influenza A virus endemic to birds, currently perceived as a significant emerging pandemic threat

Toxicity

2009-04-30T09:32:00.000-07:00

Toxicity is the degree to which a substance is able to damage an exposed organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell (cytotoxicity) or an organ (organotoxicity), such as the liver (hepatotoxicity). By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or society at large.

A central concept of toxicology is that effects are dose-dependent; even water can lead to water intoxication when taken in large enough doses, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect

Pig Influenza Virus / Testimonial in México

2009-04-29T10:53:00.000-07:00

A Worker of a Health Institute Speaks About Medical Negligence
April 13, Oaxaca. A woman died because of the pig influenza. That was the first case registered in México, according to Dr. José Angel Córdoba Villalobos, the actual Secretary of Health. Now the pig influenza is affecting most in Mexico City.

The secretary said this Saturday, that 20 out of 81 deaths for lung infections in the country had been confirmed as cases of pig influenza. About 1,324 people suspected with influenza are under study right now. Other states with people sick of flu, although not confirmed for influenza, are San Luis Potosí (62 cases and 4 people died for pneumonia) Veracruz and Estado de México.

Recommendations to avoid influenza

In order to prevent the transmission of influenza, the Secretary of health in México indicated to:
1. Avoid crowded places
2. Avoid close spaces
3. Avoid salutations with the hand and kisses
4. Wear tissues to cover mouth and nose
5. Go to the doctor at the minimal sign of flu
6. Enhance your immunologic system
7. Wash your hands with soap and water frequently
8. Sneeze in the arm, under the elbow, instead of doing it in the hand
9. Try to stay at home.
10. Never self-medicate
11. Eat fruit and do not drink alcohol nor smoke
12. Avoid sick people

Supposedly there was negligence in a case of pig influenza. Absolutely not confirmed or investigated.

According to the testimonial of a woman who said to work in the National Institute of Breathing Disease (Instituto Nacional de Enfermedades Respiratorias, INER in Spanish) they received a patient infected with the pig virus of influenza on march 2009. The man, who was coming from Tabasco, didn't survive, neither the 16 patients he transmitted the virus to, including a baby. The anonymous worker said it was a medical negligence.

Her voice was distorted in the radio (Radio Trece 1260 AM) during the news program of Jorge Santa Cruz, on April 24. For obvious reasons she preferred not to be identified. It is likely to figure out that such a serious declaration may affect her work, and the interests of some important persons in the institution.

Privacy Policy for http://www.sciencawy.blogspot.com/

2009-04-25T09:02:00.000-07:00

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fundamentals of quantum chemistry molecular spectroscopy and modern electronic structure computations - michael mueller

2009-04-18T02:15:00.000-07:00

H2S

2009-04-14T11:36:00.001-07:00

Handbook of Lasers

2009-04-11T08:25:00.001-07:00

Introduction to Biotechnology and Genetic Engineering

2009-04-11T08:24:00.001-07:00

A Complete Handbook of Natural Cures

2009-04-11T08:23:00.002-07:00

Chemistry of Pyrotechnics

2009-04-11T08:23:00.001-07:00

Avionics Handbook

2009-04-11T08:22:00.001-07:00

Handbook of Mathematics for Engineers and Scientists

2009-04-11T08:21:00.000-07:00

HANDBOOK OF ELECTRICAL INSTALLATION PRACTICE

2009-04-11T08:20:00.002-07:00

Bio Analytical Chemistry - Susan r. Mikkelsen

2009-04-11T08:20:00.001-07:00

Creative Chemistry

2009-04-11T08:18:00.000-07:00

Elementary and Secondary Education for Science and Engineering

2009-04-11T08:16:00.002-07:00

Water Chemistry of Coalbed Methane Reservoirs; Central Alberta, 2005

2009-04-11T08:16:00.001-07:00

The Vocabulary and Concepts of Organic Chemistry (Second Edition)

2009-04-11T08:15:00.001-07:00

Security Engineering by Ross Anderson

2009-04-11T08:14:00.002-07:00

Handbook for Developing Watershed Plans

2009-04-11T08:14:00.001-07:00

Pharmaceutical Process Engineering

2009-04-11T08:13:00.002-07:00

Molecular Biology in Medicinal Chemistry - D Steinhilber

2009-04-11T08:13:00.001-07:00

Fundamentals Handbook Electrical Sciences Vol 1

2009-04-11T08:10:00.000-07:00

Thorpe's Dictionary of Applied Chemistry Vol.1

2009-04-11T08:08:00.000-07:00

Handbook of Structural Engineering

2009-04-11T08:00:00.000-07:00

Power Electronics Handbook

2009-04-11T07:55:00.000-07:00

Handbook of Chemical Engineering Calculations

2009-04-11T06:02:00.000-07:00

Handbook of Chemical Engineering Calculations ARMANI1 If solving chemical engineering problems quickly and accurately is key to your work, here's an invaluable info-packed resource:

Fully revised and expanded, this Third Edition delivers step-by-step procedures for performing a wide array of chemical engineering calculations -- along with fully worked-out examples that help you avoid costly errors.

With practical techniques that help you solve problems manually, or by setting up computer-based procedures, this authoritative guide features new sections covering:

* Biotechnology
* Water pollution control
* Chemical process plant cost engineering

And revised and updated sections on:
* Physical and chemical properties
* Stoichiometry
* Chemical equilibrium
* Reaction kinetics and reactor design
* Flow of fluids and solids
* Heat transfer
* Distillation
* Crystallization
* Absorption and stripping
* Filtration
* Liquid agitation
* Size reduction
* Air pollution control
* And much, much more!
An indispensable tool for chemical engineers, this handbook will minimize your effort -- and maximize your output!

Quantum numbers

2009-04-03T12:56:00.000-07:00

1. The principal quantum number symbolized
by the letter n. The principal quantum
number tells which shell the electron is in
and can take on integral values starting
with 1. The higher the principal quantum
number, the farther the orbital is from the
nucleus. A higher principal quantum number
also indicates a higher energy level.
Letters may also be used to designate the
shell. Orbitals within the same shell have
the same principal quantum number.

2. The angular momentum quantum number
is symbolized by the letter l. The angular
momentum quantum numbers gives the
shape of an orbital. Values for l depend on
the principal quantum number and can
assume values from 0 to n–1. When l = 0,
the shape of the orbital is spherical,
and when l = 1, the shape is a threedimensional
figure eight (see representations
in Figure 4.6). As the value of l
increases, more complex orbital shapes
result. Letter values are traditionally used
to designate l values.

The letter designation originated from
spectral lines obtained from the elements.
Lines were characterized as sharp, principal,
or diffuse (s,p,d). Lines after d were
labeled alphabetically starting from the
letter f.
3. The magnetic quantum number symbolized
by ml. The magnetic quantum number gives the orientation of the orbital in
space. Allowable values for ml are integer
values from -l to +l, including 0. Hence,
when l _ 0, then ml can only be 0, and
when ml = 1, ml can be _1, 0, or +1.
4. The spin quantum number symbolized by
ms. The spin quantum number tells how
the electron spins around its own axis. Its
value can be _1⁄2 or _1⁄2, indicating a spin
in either a clockwise or counterclockwise
direction

Atomic Structure

2009-04-03T12:55:00.001-07:00

Atomic Structure
With the discovery of the neutron, a
basic atomic model consisting of three fundamental
subatomic particles was complete.
While discoveries were being made on the
composition of atoms, models were advanced
concerning the structure of the atom.
John Dalton considered atoms to be solid
spheres. In the mid-1800s, one theory considered
atoms to consist of vortices in an
ethereal continuous fluid. J.J. Thomson put
forth the idea that the negative electrons of
atoms were embedded in a positive sphere.
Thomson’s model was likened to raisins
representing electrons in a positive blob of
pudding; the model was termed the “plumpudding”
model as shown in Figure 4.3. The
negative and positive parts of the atom in
Thomson’s model canceled each other,
resulting in a neutral atom.
A clearer picture of the atom began to
emerge toward the end of the first decade
of the twentieth century.

This picture was greatly aided by several significant discoveries
in physics. In 1895 while observing the
glow produced by cathode rays from a
sealed Crookes tube, Wilhelm Conrad
Roentgen (1845–1923) noticed that nearby
crystals of barium platinocyanide glowed.
Barium platinocyanide was a material used
to detect cathode rays, but in this case, the
cathode rays should have been blocked by
the glass and an enclosure containing the
Crookes tube. Roentgen also discovered that
a photographic plate inside a desk was
exposed and contained an image of a key
resting on top of the desk. Evidently whatever
had caused the barium platinocyanide
to glow could pass through the wooden desk
but not through the metal key. Roentgen
coined the term “x-rays” for his newly discovered
rays. He was awarded the first
Nobel Prize in physics for his discovery in
1901.
Roentgen’s discovery of x-rays stimulated
great interest in this new form of radiation
worldwide. Antoine Henri Becquerel
(1852–1908) accidentally discovered the
process of radioactivity while he was
studying x-rays. Radioactivity involves the
spontaneous disintegration of unstable
atomic nuclei. Becquerel had stored uranium
salts on top of photographic plates in
a dark drawer. When Becquerel retrieved the
plates, he noticed the plates contained
images made by the uranium salts. Becquerel’s
initial discovery in 1896 was further
developed by Marie Curie (1867–1934) and
Pierre Curie (1859–1906). Marie Curie
coined the word “radioactive” to describe
the emission from uranium.
Three main forms of radioactive decay
involve the emission of alpha particles, beta
particles, and gamma rays. An alpha particle
is equivalent to the nucleus of a helium
atom. Beta particles are nothing more than
electrons. Gamma rays are a form of electromagnetic
radiation.
Physicists and chemists doing pioneer
work on atomic structure employed
radioactive substances to probe matter. By
examining how radiation interacted with
matter, these researchers developed atomic
models to explain their observations.
Rutherford along with Johannes Wilhelm
Geiger (1882–1945), creator of the first
Geiger counter in 1908 to measure radiation,
and Ernest Marsden (1889–1970) carried
out their famous gold foil experiment
that greatly advanced our concept of the
atom. Rutherford’s experimental set-up is
shown in Figure 4.4.
Rutherford used foils of gold, platinum,
tin, and copper and employed
polonium as a source of alpha particles.
According to Thomson’s plum pudding
model, alpha particles would pass through
the gold with little or no deflection. The
uniform distribution of charge in Thomson’s
model would tend to balance out the
total deflection of a positive alpha particle
as it passed through the atom. Rutherford,
Geiger, and Marsden found a significant

number of alpha particles that experienced
large deflections of greater than 90°. This
result surprised Rutherford who years later
described the phenomenon of widely scattered
alpha particles “as if you had fired a
15-inch shell at a piece of tissue paper and
it came back and hit you.” To account for
these experimental results, Rutherford proposed
a new atomic model in which the
atom’s mass was concentrated in a small
positively charged nucleus. The electrons
hovered around the nucleus at a relatively
great distance. To place the size of Rutherford’s
atom in perspective, consider the
nucleus to be the size of the period at the
end of this sentence, the electrons would
circle the nucleus at distances of several
meters. If the nucleus was the size of a
ping-pong ball, the electrons would be
about one kilometer away. Rutherford’s
planetary model represented a miniature
solar system with the electrons rotating
around the nucleus like the planets around
the sun. Most of the atom’s volume in
Rutherford’s model consisted of empty
space, and this space explained the results
from the gold foil experiment. Most alpha
particles passed through the foil with little
or no deflection. This occurred because the
net force on the alpha particle was close to
zero as it passed through the foil. The
widely scattered alpha particles resulted
when the positively charged alpha particles
approached the nucleus of a gold atom.
Because like charges repel each other, the
alpha particle would be deflected or even
back-scattered from the foil.
Niels Bohr (1885–1962) advanced
Rutherford’s model by stipulating that an
atom’s electrons did not occupy just any
position around the nucleus, but they
occupied specific orbitals to give a stable
configuration. Bohr based his ideas on a
study of the spectrum for hydrogen. A
spectrum results when light is separated
into its component colors by a prism.
When visible light passes through a prism,
a continuous spectrum similar to a rainbow
results. Light from a hydrogen discharge
tube does not produce a continuous
rainbow, but it gives a discontinuous pattern
of lines with broad black areas separating
the lines. Bohr proposed specific
electron energy levels or orbitals to
account for the lines produced in hydrogen’s
emission spectrum. In Bohr’s model,
when the hydrogen in the tube became
energized by applying a voltage, electrons
jumped from a lower energy level to a
higher level. As they moved back down,
energy was released in the form of visible
light to produce the characteristic lines of
hydrogen in its spectrum. Figure 4.5 displays
this graphically. While Bohr’s model
successfully explained hydrogen’s line
spectrum, it could not account for the
spectra obtained for gases with more than
one electron such as that for helium.
Nonetheless, Bohr had shown that matter
was discontinuous and introduced the idea
of the quantum nature of the atom.

The Divisible Atom

2009-04-03T12:54:00.002-07:00

The Divisible Atom
Dalton proposed that atoms are the
basic building blocks of matter in the early
1800s. It is one thing to claim the existence
of atoms, but it is another to develop the
concept until it is readily accepted. A century
after Lavoisier’s chemical revolution
the true nature of the atom began to unfold.
Although the question about the true nature
of the atom concerned chemists, physicists
led the way in the study of the atom. Evidence
accumulated during the 1800s indicated
that Dalton’s atoms might not be
indivisible particles. As the twentieth century
unfolded, so did the mystery of the
atom.
One area of research that raised questions
about the atom involved experiments
conducted with gas discharge tubes. Gas
discharge tubes are sealed glass tubes containing
two metal electrodes at opposite
ends of the enclosed tube (similar to small
fluorescent lights). During operation, the
metal electrodes are connected to a high
voltage power source. The negatively
charged electrode is called the cathode, and
the positively charged electrode is the
anode. Before a gas discharge tube is
sealed, most of the air is pumped out of it.
Alternatively, the tube may contain a gas
such as hydrogen or nitrogen under very low
pressure. During the last half of the nineteenth
century, numerous improvements
were made in gas discharge tubes.
William Crookes (1832–1919) observed
a faint greenish glow and beam using
his own discharge tubes called Crookes
tube. Crookes noted that the beam in his tubes originated from the cathode, and
hence, the beams became known as cathode
rays. The tubes themselves took on the name
cathode-ray tubes (Figure 4.1). Crookes
conducted numerous experiments with
cathode-ray tubes. He observed that cathode
rays moved in straight lines, but they could
be deflected by a magnet. From this work,
Crookes concluded cathode rays were some
sort of particle, but other researches believed
cathode rays were a form of light.
Part of the problem involved in interpreting
cathode rays resulted from the
ambiguous results obtained by various
researchers. For example, cathode rays were
bent in a magnetic field supporting the particle
view of cathode rays, yet when subjected
to an electric field, cathode rays were
not deflected. The fact that cathode rays
were not deflected in an electric field supported
the view that cathode rays were a
form of electromagnetic radiation or light.
The true nature of cathode rays was ultimately
determined by a group of physicists
led by J. J. Thomson (1856–1940) at the
Cavendish Laboratory at Cambridge University.
Joseph John Thomson was appointed
head of the prestigious Cavendish Laboratory
(endowed by the Cavendish family in
honor of Henry Cavendish) at the age of 28.

Thomson was a brilliant mathematician and
experimenter who tackled the problem of
cathode rays at the end of the nineteenth
century. Thomson’s initial experiments led
him to believe cathode rays were actually
negatively charged particles. Using cathoderay
tubes in which the air had been evacuated
until a very low pressure was attained
(_ 1/200 atmosphere), Thomson demonstrated
cathode-rays could indeed be
deflected by an electric field. The failure of
previous researchers to evacuate their discharge
tubes to such low pressure had prevented
the cathode-ray beams from being
deflected in an electric field. Thomson was
convinced that cathode rays were particles
or in his terms “corpuscles,” but he still had
to determine the magnitude of the charge
and mass of his corpuscle to solidify his
arguments.
Thomson and his colleagues at Cavendish
conducted numerous experiments on
cathode-rays. They used different gases
in their tubes, varied the voltage, and employed
different metals as electrodes. As the
years went by and Thomson accumulated
more and more data, he was able to calculate
a charge to mass ratio for the corpuscle.
Thomson’s results startled the scientific
community. His results showed that the
charge to mass ratio (e/m) was one thousand
times greater than the accepted value for
hydrogen ions (hydrogen ions are just
protons).

At the time, hydrogen ions were the smallest
particle known to exist. Thomson’s
results could be interpreted as either the
charge of the corpuscle being one thousand
times greater than the hydrogen ion or the
mass of the corpuscle being 1/1,000 that of
the hydrogen ion. Thomson suspected the
charge of the corpuscle was equal and opposite
to that of the hydrogen ion, and therefore,
assumed the corpuscle had a mass of
1/1,000 of a hydrogen ion. Thomson published
his results in 1897. Thomson’s corpuscles
eventually came to be called
electrons based on a term coined by George
Stoney (1826–1911) to designate the fundamental
unit of electricity.
While Thomson’s work proved the existence
of electrons, his studies still left open
the question of the exact charge and mass of
the electron. Robert Andrew Millikan
(1868–1953) tackled this problem at the
University of Chicago by constructing an
instrument to measure the mass and charge
of the electron (Figure 4.2). Millikan’s
instrument consisted of two parallel brass
plates separated by about one centimeter. A
pinhole-size opening drilled into the top
plate allowed oil droplets sprayed from an
atomizer to fall between the two plates. The
opening between the two plates was brightly
illuminated and a microscopic eyepiece
allowed Millikan to observe individual oil
droplets between the two plates. Millikan
calculated the mass of oil droplets by measuring
how long it took an oil droplet to
move between the two uncharged plated.
Next, Millikan charged the top brass plate
positive and the bottom plate negative.

He also used an x-ray source to negatively
charge the oil droplets when they entered
the space between the plates. By varying the
charge, Millikan could cause the oil droplets
to rise or stay suspended between the plates.
Using his instrument and knowing the mass
of the oil droplet enabled Millikan to calculate
the charge of the electron, negative. In
1913 Millikan determined that the charge of
an electron was _1.591 _ 10_19 coulomb.
This is within 1% of the currently accepted
value of _1.602177_ 10_19 coulomb. With
Millikan’s value for charge, the electron’s
mass could be determined. The value was
even smaller than given by Thomson and
found to be 1/1,835 that of the hydrogen
atom. Millikan’s work conducted around
1910 gave definition to Thomson’s electron.
The electron was the first subatomic particle
to be discovered, and it opened the door
to the search for other subatomic particles.
In their studies with cathode rays,
researchers observed different rays traveling
in the opposite direction of cathode rays. In
1907, Thomson confirmed the rays carried
a positive charge and had variable mass
depending on the gas present in the cathoderay
tube. Thomson and others found the positive
rays were as heavy or heavier than
hydrogen atoms. In 1914, Ernest Rutherford
(1871–1937) proposed that the positive rays
were composed of a particle of positive
charge as massive as the hydrogen atom.
Subsequent studies on the interaction of
alpha particles with matter demonstrated
that the fundamental positive particle was
the proton. By 1919, Rutherford was credited
with identifying the proton as the second
fundamental particle.
The last of the three fundamental particles
is the neutron. Experimenters in the
early 1930s bombarded elements with alpha
particles. One type of particle produced had
the same mass of the proton, but carried no
charge. James Chadwick (1891–1974), in
collaboration with Rutherford, conducted

Avogadro’s

2009-04-03T12:54:00.001-07:00

Gay-Lussac and Avogadro’s
Hypothesis
Dalton’s work provided a system for
representing chemical reactions, but inevitably,
conflicts arose when trying to resolve
Dalton’s idea on chemical combination with
experimental evidence. According to Dalton,
one volume of nitrogen gas combined
with one volume of oxygen to give one volume
of nitrous gas (nitric oxide). Dalton
referred to combination of atoms as compound
atoms. Using Dalton’s symbols, this
reaction would be represented as

But when one volume of nitrogen reacted
with one volume of oxygen, the result was
two volumes of nitrous oxide, not one.
Joseph Louis Gay-Lussac (1778–1850) had
experimentally demonstrated that two volumes
of nitrous gas result from combining
one volume of nitrogen with one volume of
oxygen. Dalton could not use atomic theory
to explain Gay-Lussac’s results. Berzelius
knew Gay-Lussac’s experiments were correct
and supported Gay-Lussac’s hypothesis
that volumes combined just like atoms. This
meant equal volumes of gases contained
equal numbers of atoms. If Gay-Lussac was
correct, then volumes could be used to
determine the correct formulas. All one
would have to do is determine the ratio of
combining volumes. This would be similar
to the practice of using the ratio of combining
masses. Employing gas volumes gave
chemists another method for determining
atomic masses. It must be remembered that
at the time different formulas were obtained
depending on the atomic mass used. For
example, the formula for water could be
HO, H2O, HO2, or H2O2 depending on
which values were used for the masses of
hydrogen and oxygen.
One way to resolve the problem of combining
volumes was to split the combining
atoms in two before the combination. But
atoms were supposed to be indivisible, and
so this was not an acceptable solution.
Berzelius urged Dalton to reexamine his
ideas in light of Gay-Lussac’s findings, but
Dalton would not accept Gay-Lussac’s
results. In 1811, Amedeo Avogadro (1776–
1856) resolved the problem using both
Dalton and Gay-Lussac’s ideas. Avogadro
hypothesized that equal volumes of gases
contain equal numbers of molecules as
opposed to atoms. Avogadro took the basic
unit of a gas as a molecule not an atom. This
meant when nitrogen and oxygen combined,
the reaction could be represented as

Avogadro had no experimental evidence to
back his claim, yet his hypothesis solved the
problem. It took fifty years for the scientific
community to accept Avogadro’s idea.
Today, we take for granted that common
gases such as hydrogen, oxygen, and nitrogen
exist as molecules rather than atoms in
their natural state.

The Atom

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Dalton and the Birth of the
Atomic Theory
John Dalton (1766–1844) was a Quaker
and largely self-educated schoolteacher who
developed an interest in chemistry as a
result of his work in meteorology. His early
scientific work included essays on meteorological
observations, equipment, and colorblindness
(Daltonism). As a result of his
interest in meteorology and the atmosphere,
Dalton turned his attention to a study of
gases. He discovered that the vapor pressure
of water increases with temperature. Dalton
considered air to be a mixture of gases
rather than a chemical compound, and he
formulated the concept of partial pressure.
Dalton determined that the total pressure of
air was the sum of the individual pressures
exerted by individual gases in a mixture.
Furthermore, the pressure exerted by each
gas was independent of the other gases present
in the mixture.
One question that Dalton considered
and which guided his formulation of the
atomic theory was why the gases in air
formed a homogenous mixture and did not
separate according to density. Dalton knew
that water vapor was lighter than nitrogen,
and nitrogen was lighter than oxygen. Why
then didn’t these gases form stratified, or
separate, layers in the atmosphere? The reason
for this according to Dalton was that
gases diffused in each other. According to
Dalton, the forces between different gas particles
were responsible for the mixing of
gases in the atmosphere. Like gas particles
repelled each other, and unlike gas particles
were neutral with respect to each other.
In attempting to explain the behavior of
gases, Dalton experimented on the solubility
of gases in water. Dalton’s work on solubility
was done with his close colleague
William Henry (1774–1836). Dalton was
convinced that the different solubility of
gases in water was due to the weight of the
ultimate particle of each gas, heavier particles
being more soluble than lighter particles.
Dalton needed to know the relative
weights of the different gases to support his
ideas on gas solubility. This need led him to
develop a table of comparative weights of
ultimate gas particles. In 1803, he presented
his table of relative weights (Table 4.1).
Over the next five years, he continued to
develop his ideas on atomism and work on
atomic weights.
As a result of his work on relative
weights, Dalton formulated the Law of
Multiple Proportions, which states that
when elements combine to form more than
one compound, then the ratio of the masses
of elements in the compounds are small
whole number ratios of each other. For
example, the elements carbon and oxygen
form the two compounds carbon monoxide
(CO) and carbon dioxide (CO2). The ratio of

carbon to oxygen masses using Dalton’s
Table would be

Dalton’s Law of Multiple Proportions meant
that two elements combine in simple whole
number ratios. Dalton believed that compounds
found in nature would be simple
combinations. Hence, knowing that hydrogen
combines with oxygen to give water,
Dalton’s formula for water would consist of
1 H and 1 O. Its formula would be HO using
modern nomenclature. Both Proust’s Law of
Definite Proportions and Dalton’s Law of
Multiple Proportions are outcomes of an
atomic view of nature. In 1808 Dalton published
his table of relative atomic weights
along with his ideas on atomism in A New
System of Chemical Philosophy.
Because Dalton did not know the chemical
formula for compounds, he assumed the
greatest simplicity. This worked fine for
some compounds such as CO or NO, but
introduced error for other compounds, for
example, assuming water was HO. Nevertheless,
Dalton’s ideas laid the foundation
for the modern atomic theory. Dalton’s ideas
briefly summarized are:
1. Elements are made of tiny indivisible particles
called atoms.
2. Elements are characterized by a unique
mass specific to that element.
3. Atoms join together in simple whole number
ratios to make compounds.
4. During chemical reactions, atoms rearrange
themselves to form new substances.
5. Atoms maintain their identity during the
course of a chemical reaction.
Dalton’s work on relative weights, multiple
proportions, and the atomic theory did
not have an immediate effect on chemists of
his day. Dalton’s ideas did provide a framework
for determining the empirical formula
of compounds, but his table of relative
weights was not accurate enough to give
consistent results. Many scientists still
debated the existence of atoms in the second
half of the nineteenth century. Still, little by
little, the atomic theory was adopted by
chemists as a valid model for the basic
structure of matter. While Dalton continued
his life as a humble tutor in Manchester,
other chemists used Dalton’s ideas to establish
the atomic theory. Foremost among
these was Jِns Jacob Berzelius (1779–
1848) of Sweden, the foremost chemical
authority of the first half of the nineteenth
century.

Modern Chemistry

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The Beginnings of Modern
Chemistry
Jan Baptista van Helmont (1577–1644)
was one of the early iatrochemists who followed
the practices of Paracelsus. Van Helmont
developed the idea of a gas, which he
distinguished from ordinary air. He used the
term “spiritus sylvestrius” to describe the
gas produced during the combustion process,
and he realized that this same gas also
was produced during fermentation and when
acids reacted with sea shells. To van Helmont,
a gas was a substance that could not
be retained in a vessel and was invisible. Van
Helmont considered air and water as the
basic elements of matter, and so he never
associated different gases as new substances.
Because he could condense water vapor but
not ordinary air, he used the Greek word for
chaos, “khaos.” The Greek “kh” is phonetically
pronounced as “g” in Flemish, and the
result was the English word gas. To van Helmont,
a gas was modified water, and water
was the basis for chemical change. In one of
his experiments van Helmont attempted to
prove that plants were transformed water.
Van Helmont planted a willow in a measured
weight of soil. Reweighing the soil and willow
after five years of watering, van Helmont
discovered no change in the weight of the
soil, but the willow had gained approximately
80 kilograms of weight. From this,
van Helmont concluded the water had been
converted into plant mass.

History of Chemistry

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Early History
Chemistry is often called the central science.
It derives this name because of its
importance to all the other sciences.
Although chemistry did not exist as a modern
science until two hundred years ago,
humans have used chemistry from prehistoric
times. Evidence of the early uses of
chemistry includes cave paintings dating
from 25,000 B.C. It is not hard to imagine
our ancestors obtaining natural pigments by
squeezing berries or mixing crushed rocks
with water to produce different colors to use
as paints. Similar processes could have been
used to obtain dyes for clothes or for body
decorations. Fragrances obtained from
flower extracts or fats rendered from animals
were the prehistoric version of the cosmetic
and repellant industry. Evidence for
the use of fermentation to produce wine
and beer dates from the earliest civilizations.
Fermentation involves the conversion of
glucose to ethyl alcohol (ethanol) in the
presence of yeast:
One of the earliest uses of fire was in pottery
making. Early humans undoubtedly
observed that when clay was heated its
water was driven out and a hard rock substance
remained. Our ancestors made clay
implements and art fixtures by heating their
work in open pit fires, and clay implements
from 20,000 years ago have been found.
Early human civilizations used stone,
bone, and wood for objects. Approximately
ten thousand years ago, metals first appeared.
The first metals used were those
found in their native form, or in a pure,
uncombined state. Most metals today are
acquired from an ore containing the metal
in combination with other elements such as
oxygen. The existence of native metals is
rare, and only a few metals exist in native
form. Iron and nickel were available in limited
supply from meteorites. The first metals
utilized widely by humans were copper,
silver, and gold. Pure nuggets of these metals
were pounded, in a process known as
“cold hammering,” with stones into various
shapes used for weapons, jewelry, art, and
various domestic implements. Eventually,
smiths discovered if a metal was heated it
could be shaped more easily. The heating
process is known as annealing. Because the
supply of native metals was limited, metal
items symbolized wealth and status for
those who possessed them.
The discovery that metals could be
obtained from ore-bearing minerals signaled
the true start of the metal age. The first metal
to be extracted from its ore was copper. The
technology used for firing clay could be
directly applied to the smelting of metals.
Kilns and furnaces were adapted with
troughs to capture metals obtained during
the smelting process. Smelting involved
heating the metal-bearing ore with wood or
charcoal. The carbon from the charcoal
combined with the oxygen in the ore separating
the metal from the oxygen. During
the smelting process, the sulfur, which was
often associated with metal ores, was driven
off as sulfur dioxide. Sulfur, with its characteristic
odor and yellow fumes that are
released when it burns, came to be closely
associated with the transformation of metals
and subsequently played a key role in
alchemical reactions. The earliest evidence
of the smelting of copper dates from around
6000 B.C.

Divisions of Chemistry

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The definition given in the last section is
very general. Although all chemists are
involved in the study of matter, the field is so
broad that it helps to divide chemistry into
divisions. These divisions characterize different
aspects of the study of chemistry
using some common feature. Chemistry may
be divided into the two very large divisions
of inorganic and organic chemistry.
Inorganic chemistry involves the
study of the chemical elements, their compounds,
and reactions excluding those that
contain carbon as the principal element.
Organic chemistry is the study of the
composition and the reaction of carboncontaining
compounds. The distinction
between inorganic and organic results from
the days when chemical compounds were
classified according to their origin. Inorganic
means not derived from life. Inorganic
substances were thought to originate
only from mineral, nonliving sources. Conversely,
organic compounds were thought to
have come from living plant or animal
sources. All organic substances contain carbon,
and it was once believed that these carbon
substances could originate only from a
living source. We know today that many
organic compounds are synthesized from
inorganic, nonliving sources. Some examples
include polypropylene, acrylics, and
nylon used in clothing; polystyrene (styrofoam)
used for insulation; and ethylene glycol
(antifreeze). Even though the original
distinction separating inorganic and organic
does not hold, the terms are still used to
distinguish two broad areas of chemistry.
For our purposes, we can think of organic
chemistry as simply the chemistry of carbon
compounds and inorganic chemistry as
the study of all other compounds. It should
be noted, though, that certain carbon compounds,
most notably carbon dioxide and
carbonates, are classified as inorganic.
In addition to the large divisions of
organic and inorganic chemistry, several
other large divisions of chemistry exist. Biochemistry
is the study of chemical substances
associated with living organisms. Biochemists
study the nature of biological substances.
The study of DNA, viruses, and
immune systems are examples of biochemical
research. Physical chemistry deals with
the structure of matter and how energy affects
matter. Physical chemists are concerned with
the physical characteristics of matter. Areas
of research in physical chemistry might
include how chemicals absorb light or how
much energy is released or absorbed when a
chemical reaction occurs. Closely related to
physical chemistry is the study of nuclear
chemistry. Nuclear chemistry focuses on the
study of atomic nuclei, nuclear fission reactions,
and nuclear fusion reactions. The
nucleus is the positive central portion of an
atom composed of positively charged protons
and uncharged neutrons. Fission reactions
involve the physical splitting of heavier elements
into smaller elements, and fusion
involves lighter elements physically combining
to form heavier elements, for example,
the fusion of hydrogen to form helium. Analytical
chemistry deals with techniques used
to identify and quantify the composition of
matter. Analytical chemists, as the name
implies, analyze substances for their content.
An analytical chemist might perform tasks
such as determining the sugar content of a
fruit juice, the amount of pollutant in a water
body, or the purity of a drug. Environmental
chemistry focuses on the occurence of natural
and synthetic substances in the environment
and their impact on the environment.
The study of the chemistry of pollution is a
major area of concern for environmental
chemists. Problems involving water pollution,
air pollution, solid waste, hazardous
materials, and toxic substances involve a
study of environmental chemistry. Each of
the major areas of chemistry mentioned
above, however, are not rigid divisions.
The nature of chemistry is such that the
fields of study in many areas naturally cross
over into other areas. A biochemist naturally
works in the area of organic chemistry, and
an environmental chemist who studies radiation
is concerned with nuclear chemistry.
Many branches of chemistry exist in conjunction
with other areas of science. For
example, the study of the chemistry of rocks
and minerals falls under the category of
geochemistry. The combination of medicine
and chemistry leads to medicinal chemistry.
Other divisions include agricultural chemistry,
food chemistry, petroleum chemistry,
soil chemistry, and polymer chemistry.
As chemical knowledge continues to
expand, we are certain to develop new areas
of study in chemistry. Just recently, chemists
have performed simple computer functions
using chemical reactions rather than performing
these functions electronically.
Chemical reactions that perform computer
operations bring computers closer to modeling
human thought processes. Our thoughts
result from chemical reactions that occur in
our brains. As chemists work at the forefront
of this area of technology and others, new
interdisciplinary areas will certainly develop.
Those new areas add to existing branches of
chemistry and at the same time create new
areas of study.
In the chapters to follow, the basic concepts
that guide chemists in their study of
matter are examined. In addition to introducing
these basic concepts, the historical
foundation of chemical thought, as well as
new areas of chemical research, are explored.
This knowledge is intended to give
the reader a clearer view of the wonderful
world of chemistry that is all around us; and
with this, a foundation to build upon. All
progress by scientists is dependent on the
work of those who precede them. In a letter
to Robert Hooke, Isaac Newton stated, “If I
have seen farther than others, it is because
I was standing on the shoulders of giants.”
The goal of this book is to help you see a
little farther.

What Is Chemistry

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Chemistry is the branch of science that
deals with the composition and structure of
matter and the changes that matter undergoes.
Matter is anything that has mass and
occupies spaces, which means just about
anything you consider. This book, your body
and the air you breathe are all examples of
matter. Matter is simply the stuff that makes
up our universe.
Chemistry, like all branches of science,
is a method that attempts to simplify and
organize. Every object we might consider is
a separate piece of matter, and matter can be
classified in any number of ways. One simple
classification scheme for matter is based
on the three states of matter: solid, liquid,
and gas (four if we include plasma).
Another classification scheme, and one that
is fundamental to chemistry, is classifying
matter by chemical composition. Rather
than speaking of water as a form of matter,
we can speak of water composed of approximately
11% hydrogen and 89% oxygen by
mass. Similarly, air is a mixture of matter
containing approximately 78% nitrogen,
21% oxygen, a little less than 1% argon by
volume, and an assortment of other gases in
small percentages.
Much of the history of chemistry has
concerned itself with determining the ultimate
composition of matter. The Greeks
considered all matter to be composed of different
combinations of earth, air, fire, and
water. It is only during the last two hundred
years that the modern idea of chemical elements
developed and only in the last one
hundred years that we have determined that
elements themselves are composed of
protons, neutrons, and electrons. Hence, we
can think of all matter to be composed of 91
naturally occurring elements, and protons,
neutrons, and electrons are the building
blocks that make up the elements. Chemistry
not only deals with the composition of
matter, but how the pieces of matter fit
together, that is, the structure of matter. The
structure of matter can have a major impact
on its properties. For example, carbon can
exist as a two-dimensional flat structure, or
a soft, black graphite, or in the pyramidal
three-dimensional tetrahedron shape we
know as diamond

So far, we have noted that chemistry
involves the composition and structure of
matter. But beyond knowing what the composition
of matter is and how the pieces fit
together, chemistry is about how matter
changes from one substance to another.
When we refer to chemical change, we mean
that the composition of matter has changed.
A chemical change occurs when a substance
or substances change into other substances.
For example, when hydrogen and oxygen are
brought together under the right conditions,
they can combine and change into water.
When the carbon in paper reacts with oxygen
in the air during combustion, it changes into
carbon dioxide. The key when considering
whether a chemical change has taken place is
to ask the question: do I end up with something
different from what I started? Chemical
changes result in the production of
something entirely different from the original
substances. The element sodium is a
highly reactive metal that reacts violently
with water. Chlorine is a highly toxic gas. Yet,
put sodium and chlorine together under the
right conditions and you have table salt.
Not all changes are necessarily chemical
changes. Changes may also be physical
changes. When water changes from ice to
liquid to steam, change has certainly taken
place, but not a chemical change. Water in
its solid ice state is H2O. After melting and
vaporizing, it is still H2O. The substance
water has not changed. The physical state
has changed, but not the substance. Similarly,
when sugar dissolves in water, no
chemical change takes place. We start with
sugar and water and end with sugar and
water. Again, only a physical change occurs,
because we still have sugar and water after
the sugar dissolves. To summarize, chemistry
can be thought of as the science of the
study of matter: what matter is made of, how
it is made, and the changes in matter from
one substance into another.

Removing the Skeletons From Your Server Closet

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Your server is an important part of your business. Your server equipment should be secure, safe and efficient to protect your vital business information over the long term, but it's also just as important to keep up the maintenance on your server room as well.

Let's look at some things you can do to organize your server room.

Organization

If your server room is disorganized, then imagine sliding out one server only to find another fall out on top of you. Adequate shelving for each individual server means easier access for hardware maintenance and less risk of potential equipment damage or personal injury.

Some businesses add hardware to their original servers over time, but don't plan for adequate server racks. As you add new hardware, be sure to add or modify existing shelving so that each server has its own slides or shelving.

Air Flow

When you're organizing your server room's shelving and racks, be sure you set up your room's layout to maximise airflow through the room and around your equipment. This will help prevent internal server cooling systems from overheating.

Untangling any Server Issues

Your server room will contain a lot of cables, cords, expensive equipment. While most server rooms will have cords neatly tucked away to avoid damage or potential injury, there are those with jumbles of cords stretched everywhere.

Take some time to untangle Ethernet cables, KVM cords, power cords, network cables, and any other wiring. Use clips or tiebacks to keep cables and cords neat and in order.

Power Play

It's important to evaluate your power outlets and how you're utilising them. Having a server room with only one power outlet, but hooked into multiple adapters and power boards may not only be a hazard to your equipment, it may also become a fire hazard.

Evaluate our power boards and power strips. Have extra power outlets installed if you feel you require more outlets. Always be sure you keep up to date with any power technology and maintain your server room's power needs.

Temperature

Servers tend to give off heat, which can heat up your server room quickly. More importantly, some servers can have a tendency to overheat if adequate cooling systems aren't in place to regulate the temperatures.

For the safety of your equipment and protection of your server room environment, make sure to install sufficient cooling systems to meet your requirements. If you live in an area where humidity is a factor, be sure to include humidity monitors and even humidifiers to help control the levels of moisture in your server room.

Unnecessary Server Room Items

While most businesses keep their server equipment in a dedicated server room, some businesses store a multitude of other items in a server room as well. The security of your servers and the information stored on them should be a priority, so storing unnecessary items alongside server equipment may become a hazard.

Servers can overheat and be easily damaged if adequate airflow and ventilation is blocked by close proximity to items that shouldn't be in a server room in the first place.

Remove any boxes, files or other accumulated business items you've decided to store in your server closet and make sure your equipment is uncluttered.

Derek Rogers is a freelance writer who writes for a number of UK businesses. For information on Network installation, he recommends Network 24, a leading provider of network installation services

Spectroscopy and Quantum

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Spectroscopy and quantum mechanics

Spectroscopy is basically an experimental subject and is concerned with the absorption,emission or scattering of electromagnetic radiation by atoms or molecules. As we shall see in, electromagnetic radiation covers a wide wavelength range, from radio waves to g-rays, and the atoms or molecules may be in the gas, liquid or solid phase or, of great importance in surface chemistry, adsorbed on a solid surface.
Quantum mechanics, in contrast, is a theoretical subject relating to many aspects of chemistry and physics, but particularly to spectroscopy.
Experimental methods of spectroscopy began in the more accessible visible region of the electromagnetic spectrum where the eye could be used as the detector. In 1665 Newton had started his famous experiments on the dispersion of white light into a range of colours using a triangular glass prism. However, it was not until about 1860 that Bunsen and Kirchhoff began to develop the prism spectroscope as an integrated unit for use as an analytical instrument. Early applications were the observation of the emission spectra of various samples in a flame, the origin of flame tests for various elements, and of the sun.
The visible spectrum of atomic hydrogen had been observed both in the solar spectrum
and in an electrical discharge in molecular hydrogen many years earlier, but it was not until 1885 that Balmer fitted the resulting series of lines to a mathematical formula. In this way began the close relationship between experiment and theory in spectroscopy, the experiments providing the results and the relevant theory attempting to explain them and to predict results in related experiments. However, theory ran increasingly into trouble as it was based on classical newtonian mechanics until, from 1926 onwards, Schro¨dinger developed quantum mechanics. Even after this breakthrough, the importance of which cannot be overstressed, it is not, I think, unfair to say that theory tended to limp along behind experiment. Data from spectroscopic experiments, except for those on the simplest atoms and molecules, were easily able to outstrip the predictions of theory, which was almost always limited by the approximations that had to be made in order that the calculations be manageable. It was only from about 1960 onwards that the situation changed as a result of the availability of large, fast computers requiring many fewer approximations to be made.
Nowadays it is not uncommon for predictions to be made of spectroscopic and structural properties of fairly small molecules that are comparable in accuracy to those obtainable from experiment.

Although spectroscopy and quantum mechanics are closely interrelated it is nevertheless the case that there is still a tendency to teach the subjects separately while drawing attention to the obvious overlap areas. This is the attitude I shall adopt in this book, which is concerned primarily with the techniques of spectroscopy and the interpretation of the data that accrue.

Conversion Factors

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Constants

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Radioactive contamination

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Radioactive contamination

The radiation warning symbol (trefoil).

Radioactive contamination is the uncontrolled distribution of radioactive material in a given environment. The amount of radioactive material released in an accident is called the source term.

Contents

* 1 Sources of contamination
* 2 Measurement
o 2.1 Surface contamination
* 3 Hazards
o 3.1 Low level contamination
o 3.2 High level contamination
o 3.3 Biological effects

1- Sources of contamination

Radioactive contamination is typically the result of a loss of control of radioactive materials during the production or use of radionuclides (radioisotopes). For example, if a radionuclide used in nuclear medicine is accidentally spilled, the material could be spread by people as they walk around. Radioactive contamination may also be an inevitable result of certain processes, such as the release of radioactive xenon in nuclear fuel reprocessing. In cases that radioactive material cannot be contained, it may be diluted to safe concentrations. Nuclear fallout is the distribution of radioactive contamination by a nuclear explosion. For a discussion of environmental contamination by alpha emitters please see actinides in the environment.

Containment is what differentiates radioactive material from radioactive contamination. Therefore, radioactive material in sealed and designated containers is not properly referred to as contamination, although the units of measurement might be the same.

2- Measurement

Radioactive contamination may exist on surfaces or in volumes of material or air. In a nuclear power plant, detection and measurement of radioactivity and contamination is often the job of a Certified Health Physicist.

2.1 Surface contamination

Surface contamination is usually expressed in units of radioactivity per unit of area. For SI, this is becquerels per square meter (or Bq/m2). Other units such as picoCuries per 100 cm2 or disintegrations per minute per square centimeter (1 dpm/cm2 = 166 2/3 Bq/m2) may be used. Surface contamination may either be fixed or removable. In the case of fixed contamination, the radioactive material cannot by definition be spread, but it is still measurable.

3- Hazards

In practice there is no such thing as zero radioactivity. Not only is the entire world constantly bombarded by cosmic rays, but every living creature on earth contains significant quantities of carbon-14 and most (including humans) contain significant quantities of potassium-40. These tiny levels of radiation are not any more harmful than sunlight, but just as excessive quantities of sunlight can be dangerous, so too can excessive levels of radiation.

3.1 Low level contamination

The hazards to people and the environment from radioactive contamination depend on the nature of the radioactive contaminant, the level of contamination, and the extent of the spread of contamination. Low levels of radioactive contamination pose little risk, but can still be detected by radiation instrumentation. In the case of low-level contamination by isotopes with a short half-life, the best course of action may be to simply allow the material to naturally decay. Longer-lived isotopes should be cleaned up and properly disposed of.

Unintentionally released radiation can reach humans by a variety of means.

3.2High level contamination

High levels of contamination may pose major risks to people and the environment. People can be exposed to potentially lethal radiation levels, both externally and internally, from the spread of contamination following an accident (or a deliberate initiation) involving large quantities of radioactive material. The biological effects of external exposure to radioactive contamination are generally the same as those from an external radiation source not involving radioactive materials, such as x-ray machines, and are dependent on the absorbed dose.

3.3Biological effects

See also: Radiation poisoning

The biological effects of internally deposited radionuclides depend greatly on the activity and the biodistribution and removal rates of the radionuclide, which in turn depends on its chemical form. The biological effects may also depend on the chemical toxicity of the deposited material, independent of its radioactivity. Some radionuclides may be generally distributed throughout the body and rapidly removed, as is the case with tritiated water. Some radionuclides may target specific organs and have much lower removal rates. For instance, the thyroid gland takes up a large percentage of any iodine that enters the body. If large quantities of radioactive iodine are inhaled or ingested, the thyroid may be impaired or destroyed, while other tissues are affected to a lesser extent. Radioactive iodine is a common fission product; it was a major component of the radiation released from the Chernobyl disaster, leading to many cases of pediatric thyroid cancer and hypothyroidism. On the other hand, radioactive iodine is used in the diagnosis and treatment of many diseases of the thyroid precisely because of the thyroid's selective uptake of iodine.

nuclear safety

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Introduction

General information about nuclear energy

Source : The following briefing notes were written to provide background information about nuclear power in Europe for journalists covering ENC 2002.

They deal with four separate aspects of nuclear electricity generation:

1. Economics

2. Environment

3. Safety

4. Waste Management.

There are strong economic and environmental arguments for building more nuclear power plants in Europe and other regions of the world.

There are more than 140 power reactors in the European Union, producing around 35% of all the Community’s electricity. Nuclear is the EU’s largest single energy source for power generation, ahead of coal at 29% and gas at 15%.

The power plants operate safely and reliably, producing large amounts of electricity at competitive prices. They are environmentally friendly, as they emit no greenhouse or acid rain gases and their waste is safely managed.

The nuclear industry thereby makes a valuable contribution towards achieving Europe's economic, energy supply and environmental objectives.

The nuclear energy option should be kept open and nuclear expertise should be retained, in order to:

* achieve a viable and diverse energy mix
* control airborne pollution and hold down emissions of CO2 &emdash; the main greenhouse gas
* maintain security of energy supply and energy independence
* promote economic development and employment.

Economics

Each country needs an appropriate energy strategy, reflecting its natural resources and its energy needs. Nuclear energy enables countries to:

* reduce their reliance on imported fossil fuels and electricity imports
* increase their energy independence
* strengthen security of energy supply.

2

With greater reliance on nuclear energy, countries are less likely to be seriously affected by fossil fuel shortages and sudden rises in fossil fuel prices.

Any future decline in nuclear’s contribution to EU energy supply will have serious implications for the region’s economy and environment. Phase-out policies have been pursued by certain West European coalition governments for reasons that are purely political and ideological. The political decisions involved have not been based on safety, environmental or economic arguments, and have been out of line with public opinion, according to poll results.

For the generation of bulk electricity, nuclear remains the only non-fossil energy source capable of expansion within Europe in the foreseeable future. The potential for expanding large-scale hydro is extremely limited, and nuclear fusion is still a long way off.

Wind farms and solar can play a supporting role, but the amount of power these sources can provide is extremely low compared to nuclear. They are also dependent on changeable factors, such as wind strength and sunshine. This makes them unsuitable for baseload generation, the power needed round-the-clock, day and night. Nuclear power plants, meanwhile, are an excellent source of baseload power.

The earth’s fossil resources are finite and should be preserved as much as possible, as they have important industrial uses other than power generation. Europe is heavily dependent on the Middle East and Russia for its oil and gas supplies, and political instability in certain regions could lead, at any time, to supply shortages and price rises.

On the other hand, the uranium used in nuclear fuel is available from various countries with a long history of political stability, including Australia and Canada. This has a stabilising effect on uranium prices and supply. Any rise in uranium prices would have only a minor impact on the cost of a nuclear kilowatt-hour, as fuel makes up a comparatively small part of the total cost of producing nuclear electricity. Power plants that burn fossil fuels are more fuel-intensive; producers and consumers therefore face a much greater risk of increased costs due to higher fuel prices.

Many existing nuclear power plants have already been paid for. Their operating costs are therefore low, and the electricity produced is among the cheapest in comparison with other sources. Cost projections show that new power reactors will also be competitive, even assuming low gas prices and heavy subsidies for wind power.

Pressurized Water Reactor

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Electromagnetic Waves

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Electromagnetic Waves Can Carry Information

During the twentieth century, technological development has been dominated

by the use of radio waves for transporting signals over very long distances.

This development is directly correlated to the property of electromagnetic

(EM) waves to be propagated with no absorption in a vacuum, and with very

low absorption in the atmosphere.

An electromagnetic wave gives some information about the source from

which it has been emitted, often this information is not elaborated on at all,

typically: the source is ON, or the source is OFF. Astronomical observation

is very enlightening as an important indication of this; it just indicates that a

star exists in a given direction and has emitted light having a certain color.

Engineers have been creative and have elaborated devices able to permanently

emit electromagnetic waves, with well-controlled amplitudes and/or

frequencies: it is said that a carrier wave has been produced, some of its characteristics

being modulated. These same engineers have imagined and

achieved devices able to receive the wave and to extract from it, this is said

to detect the signal of modulation.

An electromagnetic wave is thus able to carry over great distances the

information that is represented by the modulating signal. If, for this modulation,

one uses the signal of a microphone in front of which an orator is speaking,

it is seen that the speech can be broadcast. After reception, detection,

petroleum

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HISTORICAL PERSPECTIVES

Petroleum is perhaps the most important substance consumed in modern society. It provides

Not only raw materials for the ubiquitous plastics and other products, but also fuel for energy,

Industry, heating, and transportation. The word petroleum, derived from the Latin petra and

oleum, means literally rock oil and refers to hydrocarbons that occur widely in the sedimentary

rocks in the form of gases, liquids, semisolids, or solids.

From a chemical standpoint, petroleum is an extremely complex mixture of hydrocarbon

compounds, usually with minor amounts of nitrogen-, oxygen-, and sulfur-containing compounds

as well as trace amounts of metal-containing compounds .

The fuels that are derived from petroleum supply more than half of the world’s total supply

of energy. Gasoline, kerosene, and diesel oil provide fuel for automobiles, tractors, trucks,

aircraft, and ships. Fuel oil and natural gas are used to heat homes and commercial buildings,

as well as to generate electricity. Petroleum products are the basic materials used for the

manufacture of synthetic fibers for clothing and in plastics, paints, fertilizers, insecticides,

soaps, and synthetic rubber. The uses of petroleum as a source of raw material in manufacturing

are central to the functioning of modern industry.

Petroleum is a carbon-based resource. Therefore, the geochemical carbon cycle is also of

interest to fossil fuel usage in terms of petroleum formation, use, and the buildup of

atmospheric carbon dioxide . Thus, more efficient use of petroleum is of paramount

importance. Petroleum technology, in one form or another, is with us until suitable

alternative forms of energy are readily available (Boyle, 1996; Ramage, 1997). Therefore, a

thorough understanding of the benefits and limitations of petroleum recovery and processing

is necessary and, hopefully, can be introduced .

The history of any subject is the means by which the subject is studied in the hope that much

can be learnt from the events of the past. In the current context, the occurrence and use of

petroleum, petroleum derivatives (naphtha), heavy oil, and bitumen is not new. The use

of petroleum and its derivatives was practiced in pre-Christian times and is known largely

through historical use in many of the older civilizations (Henry, 1873; Abraham, 1945; Forbes,

1958a, 1958b; James and Thorpe, 1994). Thus, the use of petroleum and the development of

related technology is not such a modern subject as we are inclined to believe. However, the

petroleum industry is essentially a twentieth-century industry but to understand the evolution

of the industry, it is essential to have a brief understanding of the first uses of petroleum.

The Tigris–Euphrates valley, in what is now Iraq, was inhabited as early as 4000 BC by

the people known as the Sumerians who established one of the first great cultures of the

civilized world. The Sumerians devised the cuneiform script, built the temple-towers known as

ziggurats, an impressive law, literature, and mythology. As the culture developed, bitumen or

asphalt was frequently used in construction and in ornamental works.

.

Nevertheless, these writings do offer documented examples of the use of petroleum and

related materials.

For example, in the Epic of Gilgamesh written more than 4500 years ago, a great flood

causes the hero to build a boat that is caulked with bitumen and pitch (see for example,

Kovacs, 1990). And, in a related story (it is not the intent here to discuss the similarities of the

two stories) of Mesopotamia and just prior to the Flood, Noah is commanded to build an ark

that also includes instructions for caulking the vessel with pitch (Genesis 6:14):

Make thee an ark of gopher wood; rooms shalt thou make in the ark, and shalt pitch it within and

without with pitch.

The occurrence of slime (bitumen) pits in the Valley of Siddim (Genesis 14:10), a valley at the

southern end of the Dead Sea, is reported. There is also reference to the use of tar as a mortar

when the Tower of Babel was under construction (Genesis 11:3):

And they said one to another, Go to, let us make brick, and burn them thoroughly. And they had

brick for stone, and slime had they for mortar.

Hydrogen

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hydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H₂. With an atomic weight of 1.00794, hydrogen is the lightest element.

Hydrogen is the most abundant chemical element, constituting roughly 75% of the universe's elemental mass. Stars in the main sequence are mainly composed of hydrogen in its plasma state. Elemental hydrogen is relatively rare on Earth. Industrial production is from hydrocarbons such as methane with most being used "captively" at the production site. The two largest uses are in fossil fuel processing (e.g., hydrocracking) and ammonia production mostly for the fertilizer market. Hydrogen may be produced from water by electrolysis at substantially greater cost than production from natural gas.

The most common isotope of hydrogen is protium with a single proton and no neutrons. In ionic compounds it can take a positive charge (a cation composed of a bare proton) or a negative charge (an anion known as a hydride). Hydrogen forms compounds with most elements and is present in water and most organic compounds. It plays a particularly important role in acid-base chemistry with many reactions exchanging protons between soluble molecules. As the only neutral atom with an analytic solution to the Schrödinger equation, the study of the energetics and bonding of the hydrogen atom played a key role in the development of quantum mechanics.

Hydrogen is important in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks. Hydrogen is highly soluble in many rare earth and transition metalsand is soluble in both crystalline and amorphous metals. Hydrogen solubility in metals is influenced by local distortions or impurities in the crystal lattice.

Phase	gas
Density	(0 °C, 101.325 kPa) 0.08988 g/L
Melting point	14.01 K (−259.14 °C, −434.45 °F)
Boiling point	20.28 K (−252.87 °C, −423.17 °F)
Triple point	13.8033 K (-259°C), 7.042 kPa
Critical point	32.97 K, 1.293 MPa
Heat of fusion	(H₂) 0.117 kJ·mol⁻¹
Heat of vaporization	(H₂) 0.904 kJ·mol⁻¹
Specific heat capacity	(25 °C) (H₂) 28.836 J·mol⁻¹·K⁻¹

Covalent and organic compounds

While H₂ is not very reactive under standard conditions, it does form compounds with most elements. Millions of hydrocarbons are known, but they are not formed by the direct reaction of elementary hydrogen and carbon (although synthesis gas production followed by the Fischer-Tropsch process to make hydrocarbons comes close to being an exception, as this begins with coal and the elemental hydrogen is generated in situ). Hydrogen can form compounds with elements that are more electronegative, such as halogens (e.g., F, Cl, Br, I); in these compounds hydrogen takes on a partial positive charge. When bonded to fluorine, oxygen, or nitrogen, hydrogen can participate in a form of strong noncovalent bonding called hydrogen bonding, which is critical to the stability of many biological molecules. Hydrogen also forms compounds with less electronegative elements, such as the metals and metalloids, in which it takes on a partial negative charge. These compounds are often known as hydrides.

Hydrogen forms a vast array of compounds with carbon. Because of their general association with living things, these compounds came to be called organic compounds; the study of their properties is known as organic chemistry and their study in the context of living organisms is known as biochemistry. By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and since it is the carbon-hydrogen bond which gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry.

In inorganic chemistry, hydrides can also serve as bridging ligands that link two metal centers in a coordination complex. This function is particularly common in group 13 elements, especially in boranes (boron hydrides) and aluminum complexes, as well as in clustered carboranes.

Hydrides

Compounds of hydrogen are often called hydrides, a term that is used fairly loosely. To chemists, the term "hydride" usually implies that the H atom has acquired a negative or anionic character, denoted H⁻. The existence of the hydride anion, suggested by Gilbert N. Lewis in 1916 for group I and II salt-like hydrides, was demonstrated by Moers in 1920 with the electrolysis of molten lithium hydride (LiH), that produced a stoichiometric quantity of hydrogen at the anode. For hydrides other than group I and II metals, the term is quite misleading, considering the low electronegativity of hydrogen. An exception in group II hydrides is BeH₂, which is polymeric. In lithium aluminium hydride, the AlH₄⁻ anion carries hydridic centers firmly attached to the Al (III). Although hydrides can be formed with almost all main-group elements, the number and combination of possible compounds varies widely; for example, there are over 100 binary borane hydrides known, but only one binary aluminium hydride. Binary indium hydride has not yet been identified, although larger complexes exist.

periodic table

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Uranium hexafluoride

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About 95% of the depleted uranium produced is stored as uranium hexafluoride, (D) UF6, in steel cylinders in open air yards close to enrichment plants. Each cylinder contains up to 12.7 tonnes (or 14 US tons) of UF6. In the U.S. alone, 560,000 tonnes of depleted UF6 had accumulated by 1993. In 2005, 686,500 tonnes in 57,122 storage cylinders were located near Portsmouth, Ohio, Oak Ridge, Tennessee, and Paducah, Kentucky. The long-term storage of DUF6 presents environmental, health, and safety risks because of its chemical instability. When UF6 is exposed to moist air, it reacts with the water in the air to produce UO2F2 (uranyl fluoride) and HF (Hydrogen fluoride) both of which are highly soluble and toxic. And Storage cylinders must be regularly inspected for signs of corrosion
And leaks. The estimated life time of the steel cylinders is measured in decades.

Depleted uranium

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Depleted uranium (DU) is uranium that has a reduced proportion of the isotope Uranium-235. It is mostly made up of Uranium-238. The names Q-metal, depletalloy, and D-38, which once applied to depleted uranium, have fallen into disuse. Its high density and pyrophoricity have made it a valued component in some military applications, particularly in the form of armour-piercing projectiles. Its use in ammunition is controversial because it is released into the environment. Besides its residual radioactivity, U-238 is a heavy metal whose compounds are known from laboratory studies to be toxic to mammals, especially to the reproductive system and fetus development, causing reduced fertility, miscarriages and fetus malformations. It remains debatable whether depleted uranium is dangerous to human beings at the low quantities in which it is ingested from the environment
Sources
Depleted uranium is a byproduct of the enriching of natural uranium for use in nuclear reactors. When most of the fissile radioactive isotopes of uranium are removed from natural uranium, the residue is called depleted uranium. A less common source of the material is reprocessed spent reactor fuel. The origin can be distinguished by the content of uranium-236, produced by neutron capture from uranium-235 in nuclear reactors.
As a toxic and radioactive waste product that requires long term storage as low level nuclear waste, depleted uranium is costly to keep but relatively inexpensive to obtain. Generally the only real costs are those associated with conversion of UF6 to metal. It is extremely dense, 67% denser than lead, only slightly less than tungsten and gold, and just 16% less dense than osmium or iridium, the densest naturally occurring substances known. Its low cost makes it attractive for a variety of uses. However, the material is prone to corrosion and small particles are pyrophoric.
Production and availability
Natural uranium metal contains about 0.71% U-235, 99.28% U-238, and about 0.0054% U-234. In order to produce enriched uranium, the process of isotope separation removes a substantial portion of the
U-235 for use in nuclear power, weapons, or other uses. The remainder, depleted uranium, contains only 0.2% to 0.4% U-235. Because natural uranium begins with such a low percentage of U-235, the enrichment process produces large quantities of depleted uranium. For example, producing 1 kg of 5% enriched uranium requires 11.8 kg of natural uranium, and leaves about 10.8 kg of depleted uranium with only 0.3% U-235 remaining.
Military applications
Depleted uranium is very dense; at 19050 kg/m³, it is almost 70% denser than lead. Thus a given weight of it has a smaller diameter than an equivalent lead projectile, with less aerodynamic drag and deeper penetration due to a higher pressure at point of impact. DU projectile ordnance is often incendiary because of its pyrophoric property.
Armor plate
Because of its high density, depleted uranium can also be used in tank armor, sandwiched between sheets of steel armor plate. For instance, some late-production M1A1HA and M1A2 Abrams tanks built after 1998 have DU reinforcement as part of its armor plating in the front of the hull and the front of the turret and there is a program to upgrade the rest
Nuclear weapons
Depleted uranium is used as a tamper in fission bombs and as a nuclear fuel in hydrogen bombs

Types of nuclear reactors

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Reflector

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The reflector reduces the leakage of neutrons by reflecting back the neutrons escaping from the core. The same material used for moderator can be used for the reflectors in the case of thermal reactors.
In the fast reactors where fast neutrons are utilized for fission, nickel, molybdenum and stainless steel reflectors are used

Moderator

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The moderator is a material that has the ability to slow down neutrons quickly and which at the same time has little tendency to absorb neutrons. Moderator is used in thermal reactor to slow down the neutrons as the fuel has high fission cross-section for low energy neutrons.
Materials used as moderators include ordinary water, heavy water, graphite, beryllium and certain organic compounds.
The moderator should be well distributed within the fuel zone or core. In some reactors the fuel materials and moderator materials are intimately mixed together.

ENRICHMENT

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Centrifuge process.

The centrifuge process uses UF6 gas as its feed and makes use of the slight difference in mass between U-235 and U-238. The gas is fed into a series of vacuum tubes, each containing a rotor one to two meters long and 15-20 cm diameter. When the rotors are spun rapidly, at 50,000 to 70,000 rpm, the heavier molecules with U-238 increase in concentration towards the cylinder's outer edge. There is a corresponding increase in concentration of U-235 molecules near the centre. These concentration changes are enhanced by inducing the gas to circulate axially within the cylinder.
The enriched gas forms part of the feed for the next stages while the depleted UF6 gas goes back to the previous stage. Eventually enriched and depleted uranium are drawn from the cascade at the desired assays.
To obtain efficient separation of the two isotopes, centrifuges rotate at very high speeds, with the outer wall of the spinning cylinder moving at between 400 and 500 meters per second to give a million times the acceleration of gravity.
centrifuge uses an aluminum rotor or a maraging steel rotor which is stronger, spins faster, and therefore enriches more uranium per machine than the centrifuge's aluminum rotor(Maraging steel is an iron alloy which is known for possessing superior strength without losing malleability. The iron base is alloyed principally with a large percentage of nickel to produce a very specific heat-treatment product. Other alloying elements include molybdenum, aluminum, copper and titanium and are added to produce intermetallic precipitates)

Uranium

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Uranium leaves the mine as the concentrate of a stable oxide known as U3O8 or as a peroxide, It still contains some impurities and prior to enrichment has to be further refined before being converted to uranium hexafluoride (UF6), commonly referred to as `hex'. The raw ore is milled, where it is ground and chemically leached. The resulting powder of natural uranium oxide is called "yellowcake". After initial refining, which may involve the production of uranyl nitrate, uranium trioxide is reduced in a kiln by hydrogen to uranium dioxide (UO2). This is then reacted in another kiln with hydrogen fluoride (HF) to form uranium tetra fluoride (UF4). The tetra fluoride is then fed into a fluidised bed reactor with gaseous fluorine to produce UF6. Removal of impurities takes place at each step.

The UF6. Particularly is moist, is highly corrosive. When warm it is a gas, suitable for use in the enrichment process. At lower temperature and under moderate pressure, the UF6 can be liquefied. The liquid is run into specially designed steel shipping cylinders which are thick walled and weigh over 15 tonnes when full. As it cools, the liquid UF6 within the cylinder becomes a white crystalline solid and is shipped in this form.
Uranium hexafluoride can be a solid, liquid, or gas, depending on its temperature and pressure. At atmospheric pressure (14.7 psia), UF6 is a solid below a temperature of 134°F (57°C) and a gas at temperatures above 134°F. Solid UF6 is a white, dense, crystalline material that resembles rock salt. Liquid UF6 is formed only at temperatures greater than 147°F (64°C) and at pressures greater than 1.5 times atmospheric pressure (about 22 psia). At atmospheric pressure, solid UF6 will transform directly to UF6 gas (sublimation) when the temperature is raised to 134°F (57°C), without going through a liquid phase. UF6 gas (sublimation) when the temperature is raised to 134°F (57°C), without going through a liquid phase.

Light

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Reflection and refraction
Snell's Law, n1sin11 = n2sin12, relates the index of refraction of one medium, the angle of
incidence of light from that medium and the index of refraction of the other medium, and the angle
of refraction in that medium. A consequence of Snell's Law is that if n1 > n2 then 11 < 12. This is
fine for small angles, but for some angle of incidence 11, the angle of refraction 12 will be 90E. At
the critical angle 1c = 11 a so-called "evanescent" wave can travel along the interface. For
incident angles larger than 1c the light is totally internally reflected, no light passes through the
interface.
Interference and diffraction
For two sources of coherent light separated by distance d (as sketched in Fig. 1), light will
destructively or constructively interfere on a screen placed far from the source. Light
constructively interferes where the distance from one source to the screen is different from the
distance of the other source to the screen by an integral number of wavelengths of the light
illuminating the sources. That is, the path length difference for the two beams equals n8, where
n is an integer ( 0, 1, 2, ... ) and 8 is the light wavelength. For destructive interference, this path
length difference must be (n+½)8, the light is out of phase. As is seen in Fig. 1, the path length
difference is dsin1, where 1 is the angle to the position of interest on the screen.
For a single slit of width D, light from the edges of the slit can interfere with light from the center
of the slit, either destructively or constructively. This is called single slit diffraction. The
condition for a minimum in intensity (a dark fringe) is Dsin1 = n8. If there are two or more slits,
you can observe the single slit diffraction pattern superimposed on the multiple slit interference
pattern. Typically D the width of slits is much less than d the spacing between slits, so the single
slit diffraction pattern is broader than the multiple slit interference pattern.
Diffraction gratings have thousands of lines per inch patterned onto a film. The gap between each
line acts as a source. The same multiple slit interference formula applies as described above, with
d the distance between lines.
Polarization
Light is a transverse electromagnetic wave, and both its electric and magnetic field amplitudes
oscillate perpendicular to its direction of travel. Consider the electric field vector of a plane wave
propagating in the x direction E(x,t) = Eosin(kx- t). The orientation of Eo is always in the yz
52
plane. If a beam of light is composed of electric field vectors with a uniform distribution in the yz
plane, it is unpolarized. If one direction for Eo is favored the light is partially polarized. Tools
have been made which can isolate one polarization from another.

laser

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An atom can absorb a photon by raising an electron from the ground state to an excited state. A
short time later, spontaneous emission takes place, and the excited atom returns to its ground
state by emitting a photon which has energy equal to the energy level difference between the
excited and ground states. The direction and phase of these spontaneously emitted photons are
completely random, which renders them useless if one wants a directed beam of light.
Albert Einstein proposed an idea he called stimulated emission of radiation, which is the basis for
all laser light emission (laser is the acronym for Light Amplification by Stimulated Emission of
Radiation). He reasoned that if a photon with the same frequency as the spontaneously emitted
photon scattered from an atom that was in its excited state, the atom could release a photon
identical to the first in frequency, direction, phase and polarization. The two photons are thus,
coherent.
The atoms inside a laser tube have to be brought to the necessary excited state independently of
the photons. This process of raising atoms to a higher energy level is known as "pumping".
Lasers can be pumped in several different ways. The helium-neon lasers you will use, work by
applying a high voltage across the laser tube. This causes the helium inside the tube to absorb
energy. After gaining energy, a helium atom eventually collides with a neon atom which absorbs
the energy that was contained in the helium atom. The neon atom then spontaneously emits a
photon which produces red light. This light corresponds to the strongest and most visible of the
wavelengths of light your helium-neon laser emits.
For a continuously emitting laser, though, a majority of the atoms must be pumped to an excited
state, that is, there must be a population inversion. This characteristic is maintained by pumping
atoms at the same rate energy is lost. Also, two mirrors are used to amplify the beam. One
mirror is almost totally reflective while the other is about 99% reflective. These mirrors are
placed at opposite ends of the laser tube. This is done so that the photons emitted along the axis
of the tube can then reflect back and forth through it, so that they may have a much higher chance
of colliding with an excited atom than light traveling in other directions. This increases the 51
number of photons stimulated along the axis of the tube on each pass. About 1% of the light
passes the aperture on each reflection and forms the coherent laser beam.
Laser light is highly directional, monochromatic and very bright. It is directional because only the
light traveling parallel to the long axis of the laser tube is amplified by stimulated emission,
multiple times. The monochromaticity of a helium-neon laser emission occurs because of the
single transition energy yielding visible photons. The high intensity is due to the large number of
sources emitting in coherence.

ADDITION POLYMERISATION

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Addition polymerisation, the main type with which this volume is concerned,
is essentially a chain reaction, and may be defined as one in which only a small
initial amount of initial energy is required to start an extensive chain reaction
converting monomers, which may be of different formulae, into polymers.
A well-known example of a chain reaction is the initiation of the reaction
between hydrogen and chlorine molecules. A chain reaction consists of three
stages, initiation, propagation and termination, and may be represented simply
by the progression:
Activation +M +M +nM
M M* M2* M3* Mn+3 etc.
The mechanism of polymerisation can be divided broadly into two main
classes, free radical polymerisation and ionic polymerisation, although there
are some others.† Ionic polymerisation was probably the earliest type to be
noted, and is divided into cationic and anionic polymerisations. Cationic polymerisation
depends on the use of catalysts which are good electron acceptors.
Typical examples are the Friedel–Crafts catalysts such as aluminium chloride
AlCl3 and boron trifluoride BF3.
Monomers that polymerise in the presence of these catalysts have
substituents of the electron releasing type. They include styrene C6H5CH:CH2
and the vinyl ethers CH2:CHOCnH2nC1 [7].
Anionic initiators include reagents capable of providing negative ions,
and are effective with monomers containing electronegative substituents such
† Some modern sources prefer to refer to addition polymerisation and stepwise polymerisation.
as acrylonitrile CH2:CHCN and methyl methacrylate CH2:C_CH3_COOCH3.
Styrene may also be polymerised by an anionic method. Typical catalysts
include sodium in liquid ammonia, alkali metal alkyls, Grignard reagents and
triphenylmethyl sodium _C6H5_3C-Na.
Amongst other modern methods of polymerisation are the Ziegler–Natta
catalysts and group transfer polymerisation catalysts .Ionic polymerisation
is not of interest in normal aqueous polymerisation since in general
the carbonium ions by which cationic species are propagated and the corresponding
carbanions in anionic polymerisations are only stable in media of
low dielectric constant, and are immediately hydrolysed by water.

Emulsion

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synthesis of carbon nanotubes

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The arc-evaporation
which produces the best quality nanotubes, involves passing a current of about 50 amps between two graphite electrodes in an atmosphere of helium. This causes the graphite to vaporise, some of it condensing on the walls of the reaction vessel and some of it on the cathode. It is the deposit on the cathode which contains the carbon nanotubes. Single-walled nanotubes are produced when Co and Ni or some other metal is added to the anode.

Chemical vapor deposition (CVD)
This method is carrying out by passing a carbon-containing gas, such as a hydrocarbon, over a catalyst. The catalyst consists of nano-sized particles of metal, usually Fe, Co or Ni. These particles catalyse the breakdown of the gaseous molecules into carbon, and a tube then begins to grow with a metal particle at the tip. It was shown in 1996 that single-walled nanotubes can also be produced catalytically. The perfection of carbon nanotubes produced in this way has generally been poorer than those made by arc-evaporation, but great improvements in the technique have been made in recent years. The big advantage of catalytic synthesis over arc-evaporation is that it can be scaled up for volume production.

Laser ablation
a pulsed laser vaporizes a metal-graphite target in a high temperature reactor while an inert gas is bled into the chamber . The nanotubes develop on the cooler surfaces of the reactor, as the vaporized carbon condenses. A water-cooled surface may be included in the system to collect the nanotubes.
This method has a yield of around 70% and produces primarily single-walled carbon nanotubes with a controllable diameter determined by the reaction temperature. However, it is more expensive than either arc evaporation or chemical vapor deposition

structure of carbon nanotubes

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The bonding in carbon nanotubes is sp², with each atom joined to three neighbours, as in graphite. The tubes can therefore be considered as rolled-up graphene sheets (graphene is an individual graphite layer). There are three distinct ways in which a graphene sheet can be rolled into a tube .

properties of carbon nanotubes

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Strength
Carbon nanotubes are one of the strongest and stiffest materials known , This strength results from the covalent sp2 bonds formed between the individual carbon atoms. In
2000, a multi-walled carbon nanotube was tested to have a tensile strength of 63 GPa. In comparison, high-carbon steel has a tensile strength of approximately 1.2 GPa. CNTs have very high elastic modulus, on the order of 1 TPa.
CNTs are not nearly as strong under compression. Because of their hollow structure and high aspect ratio, they tend to undergo buckling when placed under compressive, torsional or bending stress.

Electrical
Because of the symmetry and unique electronic structure of graphene, the structure of a nanotube strongly affects its electrical properties. then the nanotube is metallic, otherwise the nanotube is a semiconductor. metallic nanotubes can have an electrical current density more than 1,000 times greater than metals such as silver and copper

Thermal
All nanotubes are expected to be very good thermal conductors along the tube, but good insulators laterally to the tube axis. It is predicted that carbon nanotubes will be able to transmit up to 6000 watts per meter per kelvin at room temperature; compare this to copper, a metal well-known for its good thermal conductivity, which only transmits 385 W/m/K. The temperature stability of carbon nanotubes is estimated to be up to 2800 degrees Celsius in vacuum and about 750 degrees Celsius in air.

Natural dyes

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Animal origin
These include tyrian purple (vat dye), kermes and cochineal (mordant dyes) and techelet.
Vegetable origin
Substantive dyes include walnut hulls, safflower and turmeric, while indigo and woad are vat dyes. Mordant dyes include alizarin (madder), dyer's broom, brazilwood, quercitron bark, weld and old fustic. Cudbear is unclassified.

Inorganic dyes
These include eosin and iron buff.

Food dyes
One other class which describes the role of dyes, rather than their mode of use, is the food dye. Because food dyes are classed as food additives, they are manufactured to a higher standard than some industrial dyes. Food dyes can be direct, mordant and vat dyes, and their use is strictly controlled by legislation. Many are azoic dyes, although anthraquinone and triphenylmethane compounds are used for colours such as green and blue. Some naturally-occurring dyes are also used.

How to dye ?

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1. Choose the right fabric, first. Fabrics that are at least 80% cellulose fiber--cotton, rayon, linen, tencel, or hemp--should dye well. 50% cotton/50% polyester makes nice pastels. Cotton clothing is often sewn with non-cotton thread, which stays white, but this is not usually a problem. Avoid 100% polyester or nylon. Silk is the only protein (animal) fiber that can be dyed with this recipe.
2. Next, wash your fabric. This can be done days in advance. Unwashed fabric may not dye well.
3. Next, if you're planning to tie-dye, tie the dry garments in advance. It's easiest that way. (Tieing wet garments is a total pain, and then you're committed to dyeing that day.) See the next page for more information on tieing
4. Mixing the dyes may be done up to one week in advance. (Longer storage requires refrigeration.)
1. Dissolve urea in water....1 tablespoon (15 ml) per cup (250 ml). Urea is harmless, easy to measure, and it dissolves readily--a chemist's favorite. Make enough at one time for every color you're going to prepare. (Urea may be omitted in low water immersion dyeing.)
2. Next, dissolve dye in urea solution. The best dye to use on cotton is a good fiber reactive dye such as Procion MX, Sabracron F, or Drimarene K (buy from one of the companies listed at Sources for Supplies). (Do not use all-purpose dye such as Rit® brand dye in this type of dyeing!) Use about 4 teaspoons of dye per cup...unless the dye is or contains turquoise, in which case you must double the amount (because you really need to dye by weight, not volume, and turquoise is very light in density), or black in which case you must use 2x or 4x as much. If you are mixing primaries to make other shades, note that the powder dissolves much more easily after it's been mixed in dry form.
Put the dye solutions into squirt or spray bottles for applying the dye - buy plastic bottles specifically for this purpose.
Be careful when you measure out the dye...leave the jars open as short a time as possible, and use a face mask. Don't breathe dye! The stuff isn't very toxic, but you can become sensitized to it, which would put an end forever to your dyeing.
5. Pre-soaking the fabric. Just before dyeing, pre-soak the fabric for fifteen minutes to one hour in a solution of sodium carbonate, mixed one cup per gallon of water. This stuff is also known as washing soda (but don't buy the type sold in the grocery store - it may have undesirable additives). The kind sold for swimming pools - one brand is "pH Up" - is excellent. (Do not use sodium bicarbonate, or baking soda!)
6. Applying the dye. I like to lay the fabric nearly flat, or pleated loosely, and drip with squeeze bottles directly onto the fabric, or spray it on with a spray bottle. This part is easy and fun, but always more tiring than I expect. Be sure to wear gloves! The sodium carbonate is slightly caustic and must be washed or at least wiped off of your skin immediately after contact. (Not to mention that the dyes themselves look very odd on your hands for a couple of days afterwards--while a special hand cleaner, ReDuRan, is sold for cleaning up after dyes, it really doesn't work as well as you'd like, so you end up waiting two or three days to look normal again..)
7. Reaction time. Make sure that the fabric stays wet, for the reaction to take place, no less than two hours, but preferably eight to twenty-four hours. The amount of time required depends on the temperature. In our humid climate here, we just leave the clothing outside, trusting the urea, a humectant, to keep our fabric sufficently damp, but in drier climates you may need to use plastic wrap or plastic bags.
8. Wash the clothing. Many dyers prefer to use Synthrapol detergent in the wash water, to help prevent dyes from mixing in undesired ways. You still need to isolate very light colors (especially yellow/orange); the problem with transfer of unreacted dye from dark to light regions is reduced by waiting a full day or more before washing out, as dye which has not reacted with the fabric will tend to react with the water, if given enough time. I wash first on cold, then on warm, then on hot, using Synthrapol in each wash, and end by double-rinsing. You may need to wash the clothes separately the first few wearings, but pretty soon they are 100% colorfast and safe to wash with anything, in my experience.
9. Heat setting is NOT necessary with Procion MX dyes. The only reason to use a hot water wash is to rid the cloth of the last bits of unreacted dye. It is important to use cold water before using hot water, as hot water may, in the presence of the sodium carbonate, encourage some excess dye to become a little too closely associated with the fabric, resulting in dye that gradually rinses out over the course of many washings
How to Do Low Water Immersion Dyeing
Low Water Immersion dyeing is also known as "scrunch" dyeing, "crumple" dyeing, or "crackle" dyeing. In traditional immersion dyeing, one uses a large volume of water, frequent stirring, and the use of leveling agents such as salt and, optionally, Calsolene oil, in order to make the color as smooth and featureless as possible. Low water immersion dyeing is the opposite of this approach. In low water immersion dyeing, one uses as little water as possible, crunching the fabric together for a sort of resist effect, with as little stirring as possible.
Wonderful color gradations are the hallmark of the low water technique. Where mixing oppsite colors, such as red and green, result in ugly muddy effects in tie-dye, they result in gorgeous subtle shadings in low water immersion dyeing. The reason for this is that, in tie dyeing, one normally pre-soaks the fabric in the soda ash fixer, or else adds it to the dye solutions themselves, so that the dye immediately reacts with the first fiber it touches. There is no chance for the dye colors to blend before the reaction takes place. In contrast, the low water technique involves adding the fixer *last*, after allowing the colors to slowly blend and creep along the fabric, resulting in truly infinite gradations of color.

About the Dyes

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Your choice of dye depends directly on what kind of fabric you are using. You'll get bad results if you use a wool dye on cotton, or a cotton dye recipe on wool, or either on polyester.

History of Dyes

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Until the mid-19th century, all dyes were derived from the leaves, twigs, roots, berries, or flowers of various plants or from animal substances. Tyrian purple, used by the Phoenicians in the 15th century BC, was produced from certain varieties of crushed sea snails. The use of indigo as long ago as 3,000 BC has been documented; synthetic indigocis still an important dye because it is exceptionally fast.
The textile dyeing industry in Europe originated in the 16th century. when the Portuguese, Dutch, and English introduced indigo. Natural dyes such as Cochineal, Turmeic, Wood, Madder, and Henna remained the primary source of dye colors until the discovery of the first synthetic dye in 1856 by Sir William Henry Perkin.
Perkin, an English chemist, was working with the coal-tar derivative ANILINE when he accidentally discovered that a by product of aniline oxidation had dyeing capabilities. He established a factory to manufacture his new purple dye, mauve; other experiments began to produce new colors from aniline and other coal-tar derivatives. Alizarin was the first natural dye to be produced synthetically, (1868), and by 1880 indigo had been synthesized. By 1916, an extensive technology had developed, most of it concentrated within a German cartel that held a virtual monopoly over dye production. Only with the onset of World War II did Germany lose its position as the world’s principal supplier of dyes. Today, the U.S. dye industry, aided by the post-World War II acquisition of German technology, has become a major exporter of dyes.
By 1881 Perkin had synthesized glycocoll, cinnamic, courmarin, and several unsaturated acids. In 1878. this latter work resulted in the “Perkin synthesis,” the preparation of unsaturated acids by the condensation of an aromatic aldehyde with the salt of a fatty acid. The synthesis of coumarin was of special importance, being the first vegetable perfume ever produced from coal-tar, Perkin also undertook a comprehensive study of optical isomerism. From 1881 to the end of his life he devoted himself to a study of magnetic rotation, a tool to prove invaluable in determining organic structures.
Mordants are chemical substances formerly used to confer affinity for textile fibers to natural and early synthetic dyes. Alizarin, applied with an aluminum-salt mordant, was used extensively to produce bright red shades on cotton. Tannin and sodium stannate were used to form insoluble salts with basic dyes on silk. Chromium still is used to a limited extent in the United States, and to a greater extent abroad, with azo and basic dyes for the dyeing of wool and the printing of cotton. Chemically the quantity of a substance having the weight in grams numerically equal to its modular weight refers to mole. A mole of a substance contains 6.02257 x 1023 molecules. Given this formula, the types of dyes can be clearly discussed in the following section.

Dye

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A dye can generally be described as a colored substance that has an affinity to the substrate to which it is being applied. The dye is usually used as an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber. In contrast, a pigment generally has no affinity for the substrate, and is insoluble.
Archaeological evidence shows that, particularly in India and the Middle East, dyeing has been carried out for over 5000 years. The dyes were obtained from either animal, vegetable or mineral origin, with no or very little processing. By far the greatest source of dyes has been from the plant kingdom, notably roots, berries, bark, leaves and wood, but only a few have ever been used on a commercial scale.

Types of carbon nanotubes

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Single-walled
Most single-walled nanotubes (SWNT) have a diameter of close to 1 nanometer, with a tube length that can be many thousands of times longer. Single-walled nanotubes with length up to orders of centimeters have been produced .
Single-walled nanotubes are a very important variety of carbon nanotube because they exhibit important electric properties that are not shared by the multi-walled carbon nanotube (MWNT) variants. Single-walled nanotubes are the most likely candidate for miniaturizing electronics past the micro electromechanical scale that is currently the basis of modern electronics. The most basic building block of these systems is the electric wire, and SWNTs can be excellent conductors. One useful application of SWNTs is in the development of the first intramolecular field effect transistors (FETs). The production of the first intramolecular logic gate using SWNT FETs has recently become possible as well. To create a logic gate you must have both a p-FET and an n-FET. Because SWNTs are p-FETs when exposed to oxygen and n-FETs when unexposed to oxygen, they were able to protect half of a SWNT from oxygen exposure, while exposing the other half to oxygen. The result was a single SWNT that acted as a NOT logic gate with both p and n-type FETs within the same molecule.
Single-walled nanotubes are still very expensive to produce, and the development of more affordable synthesis techniques is vital to the future of carbon nanotechnology. If cheaper means of synthesis cannot be discovered, it would make it financially impossible to apply this technology to commercial-scale applications.

Multi-walled
Multiwalled nanotubes (MWNT) consist of multiple layers of graphite rolled in on themselves to form a tube shape There are two models which can be used to describe the structures of multiwalled nanotubes. In the Russian Doll model, sheets of graphite are arranged in concentric cylinders, a single sheet of graphite is rolled in around itself, resembling a scroll of parchment or a rolled up newspaper. The interlayer distance is close to the distance between graphene layers in graphite. The special place of Double-walled Carbon Nanotubes (DWNT) must be emphasized here because they combine very similar morphology and properties as compared to SWNT, while improving significantly their chemical resistance. This is especially important when functionalisation is required (this means grafting of chemical functions at the surface of the nanotubes) to add new properties to the CNT. In the case of SWNT, covalent functionalisation will break some C=C double bonds, leaving "holes" in the structure on the nanotube and thus modifying both its mechanical and electrical properties.

Fullerites
Fullerites are the solid-state manifestation of fullerenes and related compounds and materials. Being highly incompressible nanotube forms, polymerized single walled nanotubes (P-SWNT) are a class of fullerites and are comparable to diamond in terms of hardness. However, due to the way that nanotubes intertwine, P-SWNTs don't have the corresponding crystal lattice that makes it possible to cut diamonds neatly. This same structure results in a less brittle material, as any impact that the structure sustains is spread out throughout the material.

Torus
A nanotorus is a theoretically described carbon nanotube bent into a torus (donut shape). Nanotori have many unique properties, such as magnetic moments 1000 times larger than previously expected for certain specific radii. Many properties such as magnetic moment, thermal stability, etc. vary widely depending on radius of the torus and radius of the tube.

Corrosion & Its Electro-Chemical Nature

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All corrosion of steel in soil or water is electro-chemical in its origin and nature. There are certain conditions which must be met before a corrosion cell can function. They are:
1. There must be anodes (which are at higher potential) and cathodes (which are at higher potential).
2. There must be an electrical potential can result from a variety of conditions of pipelines.
3. There must be an electrical metallic path connecting the anode and cathode. Normally, this will be the pipe itself.
The anode and the cathode must be immersed in an electrically conductive electrolyte, which is ion meaning that of the water molecule “H2O” are broken down into positively charged Hydrogen ions “H” and negatively charged hydroxyl ions “OH”
(The usual soil moisture or water surrounding pipelines normally fulfills these conditions).
Once these condition are met, an electric current will flow an metals will be consumed at the anode. Ref. To fig. (A)
In such cells an electric current flow from the cathodic or higher potential areas, through the steel of the structure or pipeline to the anodic or lower potential areas, and hence bake through the surrounding soil or water to cathodic areas. At the anodes, where the current leaves the steel and enters the soil or water, iron ions pass into the surrounding electrolyte, thus giving rise to corrosion.
The distribution of anodic areas cathodic areas depends upon the physical and metallurgical properties of the steel surface and upon the properties of the surrounding medium.

The amount of metal that will be removed directly proportional to the amount of current flow. One ampere of direct current discharging into the usual soil electrolyte can remove approximately twenty pounds of steel in one year. This is based on the elector-chemical equivalent of the metal involved; other metals than steel will be removed at other rates, some more and some less.

Classifications of dyes

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Organic dyes
The first man-made organic dye, mauveine, was discovered by William Henry Perkin in 1856. Many thousands of dyes have since been prepared and, because of vastly improved properties imparted upon the dyed materials, quickly replaced the traditional natural dyes. Dyes are now classified according to how they are used in the dyeing process.

Acid dyes
are water-soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers using neutral to acid dyebaths. Attachment to the fiber is attributed, at least partly, to salt formation between anionic groups in the dyes and cationic groups in the fiber. Acid dyes are not substantive to cellulosic fibers.

Basic dyes
are water-soluble cationic dyes that are mainly applied to acrylic fibers, but find some use for wool and silk. Usually acetic acid is added to the dyebath to help the uptake of the dye onto the fiber. Basic dyes are also used in the coloration of paper.

Direct
or substantive dyeing is normally carried out in a neutral or slightly alkaline dyebath, at or near boiling point, with the addition of either sodium chloride (NaCl) or sodium sulfate (Na2SO4). Direct dyes are used on cotton, paper, leather, wool, silk and nylon. They are also used as pH indicators and as biological stains.

Mordant dyes
require a mordant, which improves the fastness of the dye against water, light and perspiration. The choice of mordant is very important as different mordants can change the final colour significantly. Most natural dyes are mordant dyes and there is therefore a large literature base describing dyeing techniques. The most important mordant dyes are the synthetic mordant dyes, or chrome dyes, used for wool; these comprise some 30% of dyes used for wool, and are especially useful for black and navy shades. The mordant, potassium dichromate, is applied as an after-treatment..

Vat dyes
are essentially insoluble in water and incapable of dyeing fibres directly. However, reduction in alkaline liquor produces the water soluble alkali metal salt of the dye, which, in this leuco form, has an affinity for the textile fibre. Subsequent oxidation reforms the original insoluble dye.
Reactive dyes
utilize a chromophore containing a substituent that is capable of directly reacting with the fibre substrate. The covalent bonds that attach reactive dye to natural fibers make it among the most permanent of dyes. "Cold" reactive dyes, such as Procion MX, Cibacron F, and Drimarene K, are very easy to use because the dye can be applied at room temperature. Reactive dye is by far the best choice for dyeing cotton and other cellulose fibers at home or in the art studio.

Disperse dyes
were originally developed for the dyeing of cellulose acetate, and are substantially water insoluble. The dyes are finely ground in the presence of a dispersing agent and then sold as a paste, or spray-dried and sold as a powder. They can also be used to dye nylon, triacetate, polyester and acrylic fibres. In some cases, a dyeing temperature of 130 °C is required, and a pressurised dyebath is used. The very fine particle size gives a large surface area that aids dissolution to allow uptake by the fibre. The dyeing rate can be significantly influenced by the choice of dispersing agent used during the grinding.

Azo dyeing
is a technique in which an insoluble azoic dye is produced directly onto or within the fibre. This is achieved by treating a fibre with both diazoic and coupling components. With suitable adjustment of dyebath conditions the two components react to produce the required insoluble azo dye. This technique of dyeing is unique, in that the final colour is controlled by the choice of the diazoic and coupling components.

Re-thinking on medical admission for science and healthcare

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India’s population now exceeds 100 crores and the big challenge before the Government is to provide basic healthcareto all segments of the society. In spite of the economic and technological developments and the huge investments made in the medical education sector, the doctor patient ratio is extremely low in our country, compared to that in developed countries. We need professionally qualified and competent doctors to fill gap. Therefore, it is the need of thehour to develop a comprehensive medical education policy binding to the whole country, and more investment is to be pumped into the medical education sector. But the current realities are quite dismal.

Many students who pass out from the medical colleges are ill-equipped to treat patients. This scenario has emerged with the introduction of capitation fee for medical admission, which is now a deeprooted malaise in medical admission all over the country. Students with no calibre, aptitude or interest get into the medical profession either due to the funds they command or due to parental compulsion.

Only a few with merit, talent and aptitude for the medical profession get a chance to enter the portals of the medical colleges. It is quite unfortunate that in some states, the minimum marks for the qualifying examination have been lowered, in spite of the IMC directives otherwise.
Students who get into the medical profession in the merit category through the medical entrance examination are, no doubt, competent enough to get into the system and will come out as qualified professionals. Due to their interest in the profession, they take the risk of even undergoing rigorous coaching for one more year to fulfil their dreams.

Another fact is that we cannot do away with the reservation quota due to our complex socioeconomic realities. However, it is time to have a rethink on the procedure for admission into our medical colleges. There are two pertinent reasons for this. Now we mourn the declining
quality of students who opt for conventional degree courses, and, as already mentioned, many opt for medical education because of parental pressure or due to some other reasons. In order to get around these situations, we need to think of revising the mode of admission to the medical course. In many developed countries, students opt for medical education after their pre-med or
graduation, and the age of entry is usually 21 years. Here, immediately after their +2, at the age of 17 or 18 years, students choose the course without understanding the responsibilities and
commitments that are needed for the profession.

If we decide to fix any degree in science, with biology as one of the subjects in +2, as the minimum qualification for admission to the medical course, it will serve two purposes. First, many good students will come for basic degree.

Animal research

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Medical research improves the understanding and treatment of disease. Despite
advances in other methodologies, the Academy believes that research using
animals is sometimes essential.5 The Academy supports the ‘3Rs’ that seek to:
replace the use of animals where possible, reduce the number of animals used
and refine procedures in order to minimise suffering. 6 In discussing animal
research, particularly that which involves primates, the Academy acknowledges
that the Home Office is principally concerned with the regulation of this work
rather than carrying it out.
Research using animals in the UK is regulated by the Home Office, which is
advised by the Animal Procedures Committee (APC). The current system seeks
to ensure the highest possible standards of welfare for animals in scientific
procedures. The Academy endorses the verdict of the Davidson Review, which
concluded that UK legislation governing the use of animals in scientific
procedures goes beyond the requirements of European Directive 86/609/EEC,
and recommended that statistical returns process, personal and project
licenses, should be simplified.7 8
In the case of non-human primates, the Academy wishes to draw the OSI’s
attention to the Weatherall report that concluded that there is a strong
scientific case for the carefully regulated use of non-human primates in
research where there are no other means to address clearly defined questions
of particular biological or medical importance. 9 Of particular relevance to the
use of science in the Home Office are recommendations to:
· introduce retrospective reporting on the severity of procedures for nonhuman
primates;
· accelerate work towards improving and applying current best-practice
regarding housing of non-human primates;
· further efforts to improve interactions between regulatory bodies at
national and international levels and between regulatory bodies and the
scientific community;
· act on the recommendations of the forthcoming National Centres for the
3Rs and Association of the British Pharmaceutical Industry study on
regulatory toxicology and re-examine responses to the 2002 APC report;
· urgently examine concerns that the costs and harassment by activists
are forcing scientists and research companies to purse non-human
primates work overseas; and
· give careful consideration of the creation of UK centres of excellence for
non-human primate research.
Health and criminal justice are hugely important services that are encountered
by almost everyone and rightly receive substantial resources from government.
The quality of these services is, in part, dependent upon the knowledge and
information that underpins them. Research that is relevant to the Home Office’s
mission of ‘building a safe, just and tolerant society’ is organised and integrated
with its services in a fundamentally different way from the organisation of
medical science and its subsequent integration with health services. 10 These
differences not only relate to the quality, management and use of science, but
also apply more widely in university departments and in public services relevant
to Home Office functions.
Similarly, the production of evidence fundamental to the roles of the Home
Office is organised very differently from evidence production in the medical
sciences. Research can be thought of as a continuum from basic to applied. In
the health services these categories of research have a similar status, but in
the Home Office there is much more emphasis on the theoretical, which
considers matters such as the causes of crime, rather than on applied research,
which considers matters such as interventions to prevent crime.11 A continuum
between fundamental and applied research in the Home, as is the case the
medical sciences, is important.
A principal symptom of this imbalance – and lack of emphasis on applied
science - is the absence of university police or offender management schools
and a lack of recognition of police science or offender management science in
research-intensive universities. 12 13 This model contrasts sharply with the
situation in the medical sciences where clinical academics at medical schools,
within or closely associated with hospitals and universities, integrate research,
training and service delivery. The success and widespread support for this
approach in the medical sciences perhaps indicates that it would be appropriate
for other fields such as criminal justice that would benefit from the translation
of basic research into applications.14 15The Home Office should lead the
recognition and development of police and offender management science in the
Home Office, the higher education sector and in police and offender
management services.

It is a pleasure to introduce you to St. Vincent’s Medical Center:

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General Internal Medicine
This clerkship is designed to provide maximum clinical experience in the hospital setting, with emphasis on acute care medicine patients. The student is given the opportunity to apply the basic sciences and methods taught in medical school to the clinical setting. The student is involved directly in the day-to-day work of the medical teaching team and in the care of his/her own patients in conjunction with careful and continuing supervision by the resident and the attending internist. The student will join the House staff in all departmental teaching activities. You will be on call every fourth night with the team.
Ambulatory Care
The Ambulatory care elective at St. Vincent’s Medical Center provides the fourth year medical student with a one-month block rotation in primary care medicine. History taking and physical examination techniques as they apply to ambulatory patients will be reviewed. Problem identification and problem solving, as well as health maintenance and screening will be emphasized. Medical students will see patients in both the private practice office setting an in the medical clinic setting. Continuity of care and appropriate timely follow-up are the mainstays of the experience and of good ambulatory medicine. A series of case presentations and informal lectures on selected topics in ambulatory care are provided. The student will be given a weekly self-study packet that includes a case presentation with problems to solve, as well as handouts on current medical literature and reading material.
Geriatrics
The clinical clerkship at the Jewish Home for the Elderly of Fairfield is a highly structured, comprehensive on-month rotation in Geriatric Medicine. This rotation includes direct patient care under the supervision of 11 internists with special interest and expertise in geriatric medicine. Insight is gained by working with physical therapists, occupational therapists, recreational therapists, podiatrists, and a nursing staff with unique skills in Geriatric Medicine. Included are two half-day experiences of home care in an affiliated outreach program. Patient rounds occur daily with an attending physician, as well as bi-weekly Neurology rounds and monthly Dermatology, Psychiatry and OT/PT rounds.
Pulmonary/Critical Care Medicine
Over the course of this elective, the medical student will be exposed to varied aspects in the clinical field of pulmonary/critical care medicine. Areas of clinical pulmonary such as respiratory failure, infectious lung disease, malignant disease of the lung, obstructive airway disease and pulmonary vascular disease will be covered during the course of the month. Rounds will occur daily under the supervision of an attending pulmonologist. A pulmonary fellow will work with the student on the pulmonary consultative service, and cases will be presented and discussed with the attending on daily teaching rounds. The student is also encouraged to attend MICU teaching rounds. Pulmonary function tests and their interpretation will be reviewed with the student, and the techniques of pulmonary procedures (such as bronchoscopy, thoracentesis and pleural biopsy) will be demonstrated. Attendance at outpatient pulmonary clinic, as well as weekly chest radiography conference is highly encouraged.
Gastroenterology
A written curriculum with references and pertinent articles is provided for the student, as well as access to the AGA slide series, and pictorial guide to gastroenterology. The student will make consult rounds daily, in addition to teaching rounds with the gastroenterology attending. The student will be able to attend the weekly GI conference, which will expose the student to topics in GI radiology, pathology and endoscopy. The student will also observe endoscopies and other procedures throughout the rotation.
Cardiology
During the course of this elective, the student will acquire a better knowledge of clinical cardiology, allowing improved management of common cardiovascular problems encountered in the practice of internal medicine. Exposure to clinical cases and the various diagnostic and therapeutic modalities used in the practice of cardiology, will aid in the student’s patient management abilities. The student will attend rounds in the CVU as well as be a member oft eh cardiology consultative service. EKG interpretation will be performed on a daily basis and be supervised by an attending cardiologist. One week “mini-rotations” in invasive and non-invasive cardiac services will allow for an increased understanding of diagnostic and therapeutic cardiology. Attendance at didactic cardiology conferences, as well as at interactive conferences (such as murmur rounds), is encouraged.
Infectious Diseases
During the course of this rotation, students will team to integrate their knowledge of microbiology and pharmacology into clinical situations for optimal Therapeutic decision-making. As a part of the infectious disease consultative service, the student will actively be involved in obtaining comprehensive infectious disease medical histories and will gain increased proficiency in treating infectious diseases. An attending physician will supervise the student along with a resident. The student will participate in infectious disease consultations in both the inpatient and outpatient settings, join ID rounds, team to interpret pertinent laboratory data (x-rays, culture results, microbiologic slides) and attend infectious disease clinics at St. Vincent’s Medical Center under the supervision of the ID attending.
General Surgery
This clerkship is designed to provide a diagnostic approach to patients pre-selected for surgical remedy of the disease process. Emphasis is placed on pre-operative assessment and pos-operative care. Opportunity is provided to participate in Emergency Room care of trauma patients and to conduct surgical pre-admissions evaluation. The student works closely with the Senior Surgical Resident and teaching Attending Surgeon.
Radiology
This rotation is designed to integrate the student’s basic science knowledge of anatomy and physiology into the diagnostic imaging procedures. There is emphasis on problem-solving techniques using imaging and integrating these radiological studies into the patient’s care. The student experiences one-on-one teaching with a staff radiologist to learn the art of interpreting biopsies, drainages, and arteriograms are part of the rotation. There is a reading list and materials provided by the Department of Radiology for the student. Further rotations in Nuclear Medicine and Radiation Oncology are also available.

AMAZING GIFT'S OF SCIENCE

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1. Abstract
A new era on medicine are expected to happen in the coming years. Due to the
advances in the field of nanotechnology, nanodevice manufacturing has been
growing gradually. From such achievements in nanotechnology, and recent results
in biotechnology and genetics, the first operating biological nanorobots are
expected to appear in the coming 5 years, and more complex diamondoid based
nanorobots will become available in about 10 years. In terms of time it means a
very near better future with significant improvements in medicine. In this work
we present a practical approach taken on developing nanorobots for medicine in
the sense of using computational nanomechatronics techniques as ancillary tools
for investigating manufacturing design, nanosystems integration, sensing and
actuation for medicine applications. Thus the work describes pathways that could
enable design testability, but also help scientists and profit corporations in
providing the helpful information needed to test and design integrated devises
and solutions towards manufacturing biomedical nanorobots.
2. Introduction
The use of robots in surgery has provided additional tools for surgeons enabling
minimally invasive intervention or even long distance tele-operated surgeries [1].
Indeed we may trust on human creativeness and technical capabilities that can
ever be improved in terms of technical achievements [2], [3], [6]. In recent years
the medicine has enabled significant wellness for the life quality and longevity of
the world population [11]. And for the coming years, we may be prepared to
experiment even more benefits, as results from advances that are being pursued
step by step in new fields of science, such as nanobiotechnlogy [9], [13]. With
the expected miniaturization of devices provided by several works on nanoelectromechanical systems (NEMS), nanomanufacturing has actually become
a reality [12], [14].
Hence, with the NEMS recent advances on building nanodevices, and the
development of interdisciplinary works, altogether may be translated in few years
through the development of integrated nanomachines, also known as nanorobots.
With the use of techniques that are advancing rapidly, such as nano-transducers
[22], [5], and biomolecular computing [2], [13], nanorobots are expected to be
able to operate in a well defined set of behaviors performing pre-programmed
tasks [7], [4]. Thus in the coming few years, nanorobots being tele-operated to
perform surgery, or even nanorobots continually supervising the human body in
order to assist organs that may require some kind of repair, is one of the most
expected revolutionary tools for biomedical engineering problems.
The development of nanorobots is an emerging field with many aspects under
investigation. Simulation is an essential tool for exploring alternatives in the
organization, configuration, motion planning, and control of nanomachines
exploring the human body. The work we have been done concentrates its main
focus on developing nanorobot control and design applied to nanomedicine.
Nanorobot applications could be focused mainly on two major areas, as follows:
nanorobots for surgical interventions, as well as their utilization for patients that
need constant monitoring. The nanorobots require specific controls, sensors and
actuators, basically in accordance with each kind of biomedical problem.
Advanced simulations can include various levels of detail, giving a trade-off
between physical accuracy and the ability to control large numbers of nanorobots
over relevant time scales with reasonable computational effort. Another
advantage is that simulation can be done in advance of direct experimentation. It
is most efficient to develop the control technology in tandem with the fabrication
technologies, so that when we are able to build these devices, we will already
have a good background in how to control them.
We propose computational mechatronics approaches as suitable way to enable nanoelectromechanical systems (NEMS), nanomanufacturing has actually become
a reality [12], [14].
Hence, with the NEMS recent advances on building nanodevices, and the
development of interdisciplinary works, altogether may be translated in few years
through the development of integrated nanomachines, also known as nanorobots.
With the use of techniques that are advancing rapidly, such as nano-transducers
[22], [5], and biomolecular computing [2], [13], nanorobots are expected to be
able to operate in a well defined set of behaviors performing pre-programmed
tasks [7], [4]. Thus in the coming few years, nanorobots being tele-operated to
perform surgery, or even nanorobots continually supervising the human body in
order to assist organs that may require some kind of repair, is one of the most
expected revolutionary tools for biomedical engineering problems.
The development of nanorobots is an emerging field with many aspects under
investigation. Simulation is an essential tool for exploring alternatives in the
organization, configuration, motion planning, and control of nanomachines
exploring the human body. The work we have been done concentrates its main
focus on developing nanorobot control and design applied to nanomedicine.
Nanorobot applications could be focused mainly on two major areas, as follows:
nanorobots for surgical interventions, as well as their utilization for patients that
need constant monitoring. The nanorobots require specific controls, sensors and
actuators, basically in accordance with each kind of biomedical problem.
Advanced simulations can include various levels of detail, giving a trade-off
between physical accuracy and the ability to control large numbers of nanorobots
over relevant time scales with reasonable computational effort. Another
advantage is that simulation can be done in advance of direct experimentation. It
is most efficient to develop the control technology in tandem with the fabrication
technologies, so that when we are able to build these devices, we will already
have a good background in how to control them.
We propose computational mechatronics approaches as suitable way to enable the fast development of nanorobots operating in a fluid environment relevant for
medical applications. Unlike the case of larger robots, the dominant forces in this
environment arise from viscosity of low Reynolds number fluid flow and Brownian
motion and such parameters are been implemented throughout a set of different
investigations. We have been developing practical and innovative paradigms
based on the Nanorobot Control Design (NCD) simulator that allows fast design
testability comparing various control algorithms for nanorobots and their
application for different tasks. Also such information generated by the NCD can be
useful as parameters for building nanodevices, such as transducers and actuators.

Tricky virus infects nine million PCs - Downadup” and “Conficker

2009-04-03T12:24:00.005-07:00

Anew sleeper virus that could allow hackers to steal financial and personal information has now spread to more than nine million computers in what industry analysts say is one of the most serious infections they have ever seen.
The sneaky worm uses a virtual Swiss army knife of attack techniques to infect Microsoft Windows PCs, and appears to be spreading at a fairly rapid pace. The worm, called “Downadup” and “Conficker” by different anti-virus companies, attacks a security hole in a networking component found in most Windows systems, the Washington Post reported on Saturday. According to estimates from Finnish anti-virus maker F-Secure Corp, the worm has infected between 2.4 million and 8.9 million computers during the last four days alone.
If accurate, those are fairly staggering numbers for a worm that first surfaced in late November. Microsoft issued an emergency patch to fix the flaw back in October, but many systems likely remain dangerously exposed. One reason for this is because businesses will generally test patches before deploying them on internal networks to ensure the updates don’t break custom software applications. In the meantime, an infected laptop plugged into a vulnerable corporate network can quickly spread the contagion to all unpatched systems inside that network.
But the worm also has methods for infecting systems that are already patched against the Windows vulnerability. According to an analysis last week by Symantec, the latest versions of Downadup copy themselves to all removable or mapped drives on the host computer or network. This means that if an infected system has a USB stick inserted into it, that USB stick will carry the infection over to the next Windows machine that reads it. That’s an old trick, but apparently one that is apparently still very effective.
Security experts say the worm instructs infected hosts each day to visit one or more of about 250 potential control servers—basically, pseudo-random domain names—in order to download instructions or malicious software updates from the worm’s authors. With such a system, security experts would have to register all 250 domains each day in order to kill off the worm, a costly and untenable solution. In contrast, the worm authors need only register one of those 250 domains to update all infected systems with new instructions and software. AGENCIES

This article has been posted on Times of India on 13th January 2009

Urgent advice: users are strongly recommended to ensure their antivirus databases are up to date. A patch for the windows bug/vulnerability is available from Microsoft: http://www.microsoft.com/technet/security/Bulletin/MS08-067.mspx It concern Microsoft Security Bulletin MS08-067 – Critical / Vulnerability in Server Service Could Allow Remote Code Execution (958644). Complete and effective protection measures against the worm at the end of this post.

Sources/references of this outbreak alert and background information:

Kaspersky Lab
Guardian.co.uk
Microsoft
ThreatExpert
F-Secure
Symantec
NetworkWorld
DarkReading

Symptoms of the worm:

- http://www.bitdefender.fr/VIRUS-1000462-fr–Win32.Worm.Downadup.Gen.html
- http://www.ca.com/gb/securityadvisor/virusinfo/virus.aspx?id=76852

Kaspersky Lab disinfection/removal tool:

http://support.kaspersky.com/faq/?qid=208279973

List of domains that are currently distributing the Downadup worm and its variants:

http://www.f-secure.com/weblog/archives/downadup_domain_blocklist.txt

Complete/effective protection measures against the worm, apply all 3 measures:

1. Apply Microsoft patch MS08-067:http://www.microsoft.com/technet/security/Bulletin/MS08-067.mspx
2. Provide the administrator account of the computer with a strong password (brute force dictionary attack against administrator password is used): http://www.safepasswd.com/
3. Completely disable the AutoRun function, this is a brutal but highly effective hack:http://nick.brown.free.fr/blog/2007/10/memory-stick-worms.html

downadup conficker and disabling autorun

2009-04-03T12:24:00.003-07:00

Just a quick heads up related to disabling Autorun to protect against Downadup / Conficker. While the worm continues to spread and receive more media coverage, IT personnel are working to make sure their systems are protected. One of several ways this worm spreads is by taking advantage of the Autorun feature in Windows systems. Disabling this feature via Group Policy is a logical decision, but it turns out it may not actually work like it should.

Disabling Autorun via GPO currently only disables Autoplay on media insert. However, if there is an Autorun.inf file present on a CD, USB, or network drive, the program will still run when double clicking that drive in Windows Explorer. This vulnerability was announced by the U.S. CERT team on January 20, and later updated to provide patch details from Microsoft. Follow the links below for full details on the problem and where to get the patch.

Conficker worm: Imminent threat, or another Y2K?

2009-04-03T12:24:00.001-07:00

The Conficker worm—as in an online worm, a type of virus that lives unnoticed in your PC while spreading itself to others over the Internet—has been one of the hottest online-security stories over the past few months. The worm started infecting systems big-time last fall. But the biggest chapter in this story might be yet to come.

Up to now, Conficker, which affects only Windows computers, has clogged networks and infected an estimated 12 million computers. It's also been able to shut down antivirus and other security software. "But it hasn't implemented a nasty functionality, yet," says Ed Skoudis, co-founder of IntelGuardians.

However, experts fear it may, come April 1. There's plenty of speculation about what exactly could happen on April Fool’s Day, the day Conficker is programmed to connect to other PCs forming a “botnet”, but no one knows for sure. So you'll want to take whatever steps you can to protect yourself.

That means ensuring your security-software subscription is current and checking that updates are being implemented. You should also run Windows Update—look for that or Microsoft Update on your Programs menu—to get the latest critical patches and the malicious software removal tool which will kill Conficker. Finally, this is a great time to make sure your data is fully backed up, using one of the several available options.

Scanning for Conficker with Nmap

2009-04-03T12:23:00.001-07:00

While Conficker is not a new worm it has been getting much press lately. Even though Redmond released a patch late October it is estimated that 5 to 10 million PC have been infected. The industry has been aware of this worm for some time and has mounted a fairly impressive counter attack. Microsoft issued a 250K dollar bounty for developers of Conficker, major anti-virus vendors have added definitions for detection and removal of the worm, OpenDNS introduces a feature that aid sysadmins in detecting infected machines and today with the help of HoneyNet Project security researches discovered Conficker’s fingerprint which makes it possible for tool such as Nmap, Nessus to detect the worm remotely. This discovery come just in time as the latest variant of the worm “Conficker C” is programmed to lay dormant unlike the previous generations where identification of the worm was possible by monitoring outbound traffic.

Why just in time you may ask? Well because the worm is said to become active on April 1st. It is unknown if all infected PC will be used for bad deeds. I’m sure no one needs a reminder of the SQL Slammer worm of 2003/2004 where 5 of the 11 root DNS servers went down, ATM’s where knocked offline due to massive DDOS attacks. I understand the symbolism of April 1st being April fools day, but as the doctor always says: It’s far easier to prevent then to treat.

Using the latest development version of Nmap one would run a command to scan systems for Conficker signature.
nmap -PN -T4 -p139,445 -n -v --script=smb-check-vulns --script-args safe=1 [targetnetworks]

Or by updating your Nessus server’s plugins nessus-update-plugins create and run a scan that includes plugin id #36036 (if you don’t pay for Nessus Professional feed you will have to wait 7 days to receive the plugin)

Be mindful that Conficker can also spread via sneakernet, configuring your anti-virus client to scan all attached/removable extenal memory storage devices is always a great idea.

stopping conficker with opendns

2009-04-03T12:22:00.000-07:00

Conficker is quickly becoming a mainstream news story as April 1 approaches, the date that the worm is programmed to “phone home” for further instructions. It has been discussed in various news outlets, even garnering a primetime spot on 60 Minutes this past weekend. The worm has been a great source of concern for IT execs the past couple of months, though the actual severity is yet to be determined. There are several mitigating factors that are supposed to minimize the chance for compromise, and a number of ways to detect and remove the virus. Another potential weapon against Conficker that should be considered is the use of OpenDNS to block the worm from communicating with command and control servers for further instructions.

In analyzing the virus, engineers have found that Conficker uses an algorithm to determine a number of different domains to contact for further instructions beginning on April 1. The algorithm was used to determine the exact list of domains that would be used. OpenDNS recently added a feature which would block access to these domains: “We’ve teamed with Kaspersky Lab to identify those domains, and stop resolving them. This means if you’re using OpenDNS, Conficker will do your network no damage“. From a management perspective, this is a much less intensive solution than attempting to block the domains on your local DNS servers and dealing with the overhead involved.

While using OpenDNS might not be feasible for larger enterprises, this is a great solution for SMB’s and home users. I’ve used it personally for some time now; the amount of centralized control available and ease of use makes it extremely attractive. A wealth of reporting features are also available, including one to specifically identify requests to known malware sites (like Conficker). Steps still need to be taken to ensure that Conficker is identified and removed from your network, but this is a good way to ensure that if any instances go undiscovered, they won’t be able to cause further harm.

Don't Be Beaten by the Ink Cartridge

2009-02-09T08:53:00.000-08:00

If there's one thing guaranteed to flummox half the office staff for a whole morning, it's going to be the changing of an ink cartridge in a printer or copier. God forbid you should be the one on the printer when the light comes on to tell you the ink cartridge is running low!

If this is you, then there are two options. You can either a) do what men do and retreat, whistling, as if you changed your mind and didn't want to print after all or b) take the bull by the horns, so to speak, and attempt to change the ink cartridge yourself.

How difficult can it be, I hear you ask. Well, first you have to find the right flap. You will go through a sequence of flaps from paper feeder through to paper storage to one that displays all the scary inner workings of a printer. Eventually, you will find a flap with idiot instructions on the inside. This will be a simple drawing of how to change an ink cartridge.

Except, of course, the picture won't represent anything that looks like your printer unless you tilt your head upside down, stand on one leg and squint. You begin by reading the written instructions in conjunction with trying to associate the pictures to what appears before you, swiftly giving up the latter. Basically, it will tell you to pop one out and pop the other in.

What it doesn't tell you is that it will take a degree in mechanics to get this last one out! Operations that are meant to be simple will need to be carried out by the flick of several small plastic clips which will immediately snap off in your fingers leaving the cartridge well and truly wedged. After a spell of trying to do it properly, you will then resort to wedging in plastic rulers and pens in an attempt to prize it from its location.

Bits of snapped off stationary are often responsible for printer blockages and will lead to some very loud tut tutting by printer engineers who come out on expensive call, amid what they would have you believe is a very busy schedule, and who will make it look easy. They will pick out the bits of pen, change the cartridge, look at you like you are dense and charge you an extortionate fee for the trouble.

To avoid this, most office staff will learn quickly from the pen incident and in future continue attempts at the instructions. Any fly on any office wall will tell you that you can sit back and watch one person struggling with cartridge replacement on a printer for a short period and they will soon be joined by a plethora of people that all know how to do it.

"Come here, let me have a go" is an oft bandied about phrase. They will do exactly the same as the last attemptee, but help by reading the instructions louder and slower. If it's a man looking to help a damsel in distress he will take off his jacket, roll up his sleeves and go in like he's about to perform brain surgery, demanding ruler, pen, any long, strong object and a swab for the sweat on his forehead.

Whenever an ink cartridge needs replacing, the simple answer is to call the oldest, most experienced woman in the office. With an air of confidence she will click, slap and generally be pretty heavy handed with various parts of the printer in a well practiced sequence. You will have fresh ink in no time with barely a drop of spillage.

7 Ways to Speed Up Windows Vista

2009-02-09T08:52:00.001-08:00

There are many ways to speed up Windows Vista. Some methods are more straight forward than the other and some will help you see huge improvements to the performance of Windows while others offer less noticeable results. Here we will look at 7 most effective ways to speed up Windows Vista from my personal experience.

Turn off unnecessary Windows features.

By default, Vista comes with tons of features that are enabled based on assumptions which may or may not apply to you. Hence you get a system that is running lots of background processes, most of which you do not need at all. So one of the great ways to speed up Windows Vista is to disable them. To see the list of Windows features and turn them on or off, go to Control Panel, change to "Classic View", click on "Program Features" and then select "Turn Windows Features On And Off". Some examples of features you may want to disable are:

- Remote Differential Compression

- Windows Meeting Space

- Tablet PC optional components

- And so on.

Graphical features.

One of the better ways to speed up Windows Vista is to turn off fanciful graphical features if you are not too much into aesthetics. One example is the Aero feature. Open your start menu, go to run, and type in 'systempropertiesperformance'. At the Visual Effects tab, uncheck 'Animate windows when minimizing and maximizing'. This will do the job. There are many graphical features that you can take out from here. This can give you more immediate results as compared to other ways to speed up Windows Vista.

Turn off Windows Indexing.

The Windows Indexing service was initially designed to be one of the ways to speed up Windows Vista by shortening the search time for files. However, as the volume of hard disk increases exponentially, the service has proven to be a resource intensive program causing massive slowdowns when Windows start to index the millions of files in the system. Select Start then choose Computer, right click on your C Drive and select properties. Under the General Tab, uncheck "Index this drive for faster searching". On the next dialog box, choose "Include subfolders and files". Do the same for the other Drives.

Remove Spyware and Trojans and protect your system against future attacks.

Out of the many ways to speed up Windows Vista, this has to be one of the most crucial things you need to do. This is because not only your system performance is at stake, the security and confidentiality of your data is too. Use free tools such as Avast for anti-virus protection, Spybot for spyware removal and protection as well as Zonealarm for firewall protection. There are other good tools around but make sure they are not spywares themselves!

Remove unnecessary start up programs.

When Vista boots up, many programs run at the start up either in the background or as pop up Windows. Many of these you do not need. You need to take control and eliminate these memory suckers that are lurking in the background. Open your start menu, go to run, and type in 'msconfig', choose the Startup tab and uncheck any items that you do not want to auto-load and click OK.

Defrag your hard disk.

This may not be new to you but if you are thinking of using the Windows Defragmentation Tool in Vista, you can forget about it. Instead, use a free 3rd party tool known as Defraggler (Google it for the download link). It is still quite effective in comparison to other ways to speed up Windows Vista.

Clean your registry.

One of the often neglected portions of Windows is the registry itself. Many do not realized that one of the best ways to speed up Windows Vista is to make sure the registry is clear of invalid entries that causes Windows to perform unnecessary tasks. Cleaning the registry has other advantages too. In certain cases you can remove Windows errors that pop up during boot up.

George Tho is an IT support specialist. One of the best ways to speed up Windows Vista is using registry cleaners. Read his review on the top 3 Registry Cleaners that come with free scanning features to help you improve your system's performance and remove errors.

Do You Currently Experience These Five Windows Registry Errors?

2009-02-09T08:52:00.000-08:00

Registry errors can be easy to spot in the majority of cases. There are some cases however, where it may be more difficult to figure out what is going on with your computer. There are several categories of errors or issues that you can have with your computer that is going to lead you to the registry.

The first thing is know the categories that errors are going to come in. You are either going to get slow down issues, this is where the computer ceases to function correctly by taking an excessive length of time to load programs and complete processes. It can even take a significant period of time loading on the initial start of the computer.

The other category of errors are going to revolve around the actual DLL files themselves. These library files are the core of the computer and its processes errors in this part of the registry will do more than slow your computer down.

Winsock errors are one of the big registry errors that you are going to want to look out for. These errors are going to show up as wsock32.dll errors. These types of errors indicate a problem in the files which deal with the operating system itself along with Kernel.dll errors and should be taken seriously as they can and often do lead to systems crashes or the inability to load the computer. Errors like these occur when attempting to remove older viruses.

Various run time errors can also occur and can indicate a potential registry issue. These occur when there are conflicting instructions in the registry for a particular function. Cleaning the registry out will remove the old files and usually fixes these types of errors.

Spyware is another error that has to be considered when looking into the registry errors. There are some instances where registry entries can be considered spyware and accidentally deleted. This can cause a great deal of frustration. This is not as common as it once was due to the sensitivity of spyware scanners. There are instances however when it can occur.

The same goes for viruses. There are some instances where registry entries are deleted because the virus scanner registers it as a virus. Most people simply delete the virus files when they are found and the next time you try to start and application you end up with an error.

These are five of the largest of the errors that can occur with the registry. These are usually readily identifiable though there are some instances where they may be harder to spot than others. The first thing to look for is programs that are running slower, errors involving DLL files, runtime errors and script errors, errors involving spyware and those involving false positives on virus scans that can have you removing essential files from your registry.

Having a good registry cleaner is one sure way to make sure that your computer is kept running smoothly and you can avoid these types of errors.

Pre-Cautions to Be Taken Care For Maintaining Data Centers

2009-02-09T08:51:00.001-08:00

Data Centers are a fundamental part of any organization. The accounts, information about the projects, client details, employee details and all the important data is stored here. For this important department it is necessary to have data center manager, who has the required experience in maintaining it. For data center maintenance, it is necessary for one to take necessary precautions. To help you in conveniently managing the information centers, here are few tips:

* Check for any damage on walls and ceiling of data management center. At times due to natural calamities, some cracks appear on the walls. So getting them repaired should be the priority.

* On regular basis, one needs to test backup power systems. As the generators become obsolete over the usage, it becomes essential to check that it is running fine and does not cause any power interruption when there is no electricity.

* Having a site-specific tool kit is important. This will help you in handling problem with ease and less time. Your tool kit must have screwdrivers, fans and door wedges, cabling connectors, labeling tool, blowtorch, duct tapes, flash light, spare set of batteries, entrance and exit door keys, extension power chords, phone book diary with the telephone numbers of Electrician, Fuel Distributor, HVAC tech, Diesel tech, and others . (This is not an exhaustive list but a, suggestive one only. You can always add something relevant to the list).

* One should check the air-cooling systems in the data centers and clean the air filters. This will help in keeping the complete data clean.

* Never, keep the cardboards of the new mainframes near the server. Firstly, this unnecessarily blocks the way of people around and secondly, the cardboard material is highly combustible. As the result, fire damage can occur at this place.

* Keep the food away from the data centers. Food debris in keyboard can hamper the efficiency of the system or an oily patch on screen can blur the vision.

* Prepare a comprehensive list of essential tools and inventory so that there are no problem occurs in the functioning of data center.

* For safety, reasons tie & route the cable and cords properly; never overload the weight limit the raised floors.

To know more about data center maintenance, hardware maintenance solutions, IBM Mainframe Maintenance, and call center hardware inventory maintenance, visit us.

QSGI - A complete Information Technology Solution provider to help corporations and governmental agencies better manage software assets, hardware assets, reduce maintenance expenses, build best practices for data security and assure regulatory compliance.

Troubleshooting Computer Problems

2009-02-09T08:51:00.000-08:00

Troubleshooting computer problems can be time consuming if you don't follow a plan. You need to have some idea of what you are troubleshooting for if you have any hope of discovering what the problem is!

Computer failure comes in many shapes and sizes. There are the fairly easy ones and there are the very difficult ones. Learning to know which type it is likely to be will save you time and make troubleshooting problems a whole lot easier.

The most serious of problems are probably those concerning hardware. When you hear the ominous repeating click sound of a hard disk in the throes of death, it's too late to panic; the damage has already been done.

Power supply units can often be the cause of problems in computers. You don't need a lot of experience to conclude that your power supply is no longer supplying power. Even if it is still supplying power, it may be underpowered and causing problems because of that.

Computers create heat. That's why they have a cooling fan as part of the assembly. Should the fan fail, or if it is inadequate because the manufacturer doesn't care, or if the under ventilation is inadequately provided for, you will experience all kinds of problems.

When a computer overheats it will often suddenly shut down. It does this to protect itself from over heating any more. However, it doesn't tell you that there is a problem beforehand, and that it has to shut down. It just does it. If your computer is doing this regularly, it could be an overheating problem.

Troubleshooting these kind of computer problems will require you to make an educated guess at what kind of problem it is likely to be. Pursuing that line of thinking will lead you on to other related components, and eventually you should be able to track down the real problem. For example, a problem with the sound card will exhibit itself through a sound problem and a video card problem will make itself obvious through the monitor.

Don't forget to check all the cabling and plugs first! Many a technician has been embarrassed after spending time checking everything only to finally notice a loose connection. Check the most obvious first when troubleshooting computer problems, if only to eliminate them as the source of the problem.

Sometimes troubleshooting your computer problems will lead you to a software cause. Perhaps there is a software conflict. This would likely show up soon after you installed a new program. In fact, if your problem is noticed immediately after installing a program, then that is the likely cause.

Try uninstalling the program. If that fixes the problem then you need to find out why before re-installing the program. Make sure all the software drivers are up to date before trying any more software installs.

Troubleshooting computer problems is usually never easy. It takes time and the simple plan of doing one thing at a time and checking to see what the effect is. If you do several things and suddenly everything is fine again, you'll never know what the cause was.

Always make one change, check, and if it doesn't work to improve matters, make another change, and so on. Being methodical will make troubleshooting computer problems a lot easier.

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Resolving Common Outlook Express Error Problems

2009-02-09T08:50:00.001-08:00

The most common email client that is being used in offices today happens to be Outlook Express. But what do you do when it encounters a problem? For example, you have mail in your send folder that is not sending out. This means that there is an issue with your outlook program as a whole, or even a server problem. Check out your internet service provider and make sure you have keyed in the correct details in your account setup. These are some of the common problems when people cannot send and receive mail for some reason. Also, make sure that you do not have multiple programs when running outlook express, especially programs that are using the internet as well. You can choke out your mail client, especially if your connection is slow, not a broad band, or on a shared network.

If the problem persists and if new problems seem to materialise, then it may be a virus. Check your emails for strange emails with no named recipients. These could be Trojans and worms at work within your email client. In essence, they have been designed to infiltrate clients like Outlook Express and fiddle around, steal your personal information, take your email contacts and mess up your internal email client. Another common problem is inability to download emails, or large emails seem to be taking forever to download. Check your email capacity and some people who use Outlook for a very long time do not Auto Archive their emails or even clean out their very, very old emails.

This clogs up the system and sometimes can lead to this problem. Get an antivirus which has spam guard on at all times, and make sure that it is able to work with Outlook Express. One of the most common problems with people who use Outlook is that they receive a huge amount of spam email. Or, the problem could be even worse; ISPs could identify them as a spam distributor because a worm has been implanted in the client. These problems normally affect workplace networks and business broadband internet connections. This is why adequate protection is necessary. Your Windows firewall and the one provided by the modem is not enough.

Their encryption normally does not go above 256 bit, which means that high level threats would be able to seam their way through the firewall or disguise themselves as legit emails. Only a good anti virus with Spam Guard will be able to fully protect you and your email client. If it comes to program hangs or other crashes with Outlook, then it is time to consider a good registry cleaner. One of the common problems with Outlook is bad installs, program conflicts in the registry associated with the email client and even bad code during setup. All of these problems can be erased with the simple use of a Registry Cleaner. There are many good ones available online and the good news is that they are free as well. These are some common Outlook Express problems and ways you can solve and even prevent them from happening.

Click Here to get your Outlook Express errors fixed for free. Logan Albright helps thousands of people optimize their computers through a proper computer check up. He is an authority on troubleshooting computer problems at http://www.pcaholic.com.

Troubleshooting Tips - Runtime Error R6025

2009-02-09T08:50:00.000-08:00

Runtime error r6025 is an error more commonly associated for users who are using Visual Basics or any code compiling software to develop programs. While there are some other causes of the runtime error, this article will discuss this first, then touch briefly on the other possible errors associated with this as well as some of the ways you can avoid having this runtime error again. Coders would be very familiar with this runtime error and it occurs most commonly when the application tries to execute or call on a code function that is either invalid or does not exist within its matrix.

Most of the time, Windows will detect the error and this inform the end user through the runtime error dialogue box. Most coders would suggest that you run a debug program to solve this problem as it will track down the loose code within your project and fix the problem there and then. It is relatively a minor problem when detected early. Some cases, this runtime error is a direct result of a program conflict with Norton Antivirus and some other, more popular virus software that is available to consumers.

What happens is that older systems that run older versions of their OS are not compatible with newer code that is written within new antivirus programs and thus the conflict occurs and Windows detects it as Runtime Error r 6025. These are some of the major causes of this error and the entire runtime error library has many different and varying causes. While the trouble shooting process will take a while as they each have different unique ways to solve (as can be seen with this runtime error), one of the main ways to solve any of these errors is to have a single universal solution.

Sometimes, Windows flashes these errors due to a confusion in the registry, or perhaps a virus or a worm (or even spyware) has left behind a code or embedded key within its matrix that confuses the operating system into operating it as a runtime error. Technicians all agree that one of the first steps to solving a runtime error (or also known as an error when a program execution or command line is broken) is to fix the registry.

The reason for this is because of the fact that everything is logged down into the registry and most of the time, the error can be traced in the registry as a broken command or code. A good registry cleaner can solve most of these problems by cleaning up the registry and highlighting the conflicts. Advanced registry cleaners can even solve these conflicts through a re shuffling of data within the registry, which is a good thing to have when you want a specific program to work. Runtime error r6025 and hundreds more like it can be solved with a single download and a single click of a mouse - most of the time. It is a harmless way to root out one possibility, and most of the time, it works.

Common Active X Problems and What You Can Do About Them

2009-02-09T08:49:00.001-08:00

Compatibility is a common problem when it comes to Active X controls and they can be traced to a few programs. Certain browsers and their tool bars have some compatibility issues with Active X controls. When you are installing third party tool bars on your web browser, you should be careful and check whether there are any compatibility issues with these toolbars. Some of them include the tool bars created by Google and Yahoo. Internet Explorer has many add ons from both Microsoft itself as well as third party developers.

Go online and read up about them, there may be fixes and installs that you can use to route some of these problems. Another common Active X problem is of system access rights, which sometimes does not allow the control to go into specific folders or the Windows registry itself. Some programs also do not allow Active X to access them; so what you need to do is to educate yourself on the different programs, folders and the Windows registry, and what you need to do to prevent these kinds of problems. The resources for technical support with regards to this problem are easily available online; tech forums, FAQs, etc.

The Active X website is a good source of trouble shoots that you can use to fix these access violation problems. Updated Microsoft Office Applications also have a problem with some forms of Active X controls and conflicts may arise. It is not uncommon for some Office related software to crash and display the error 429 dialogue box. This is a problem with Office applications and Active X and Microsoft has a specific repair tool for this. Going online will allow you to download several tools that will prevent this error from happening again. Looking at the myriad of Active X errors on Windows, there is a common strain that can be observed from all these faults.

More than 80% of these issues arise from the registry, where program and command conflicts come about when Active X is signed into the registry. Access and security problems also play a part, especially in business frameworks where security is of a high level due to sensitive information. But for the casual user, downloading a registry cleaner is often more than enough to rid the computer of these Active X problems. All conflicts and problems within the registry can be done away with a single scan and a registry clean up and the good news is that these registry cleaners are freely available to anyone.

As for the other aspects of Active X, there has to be some investigation into the security settings, anti virus software and the third party programs that you have installed. There is a lot of literature available online as referral to help with some of the more unique Active X problems - problems a registry cleaner cannot solve. For the rest, cleaning out the registry is a good way to get rid of some of the more common active X problems and ensure your machine runs smoothly at all times.

Click Here to get your windows registry fixed for free. Logan Albright helps thousands of people optimize their computers through a proper computer check up. He is an authority on troubleshooting computer problems at http://www.pcaholic.com.

What to Do When Your Computer Freezes Up

2009-02-09T08:49:00.000-08:00

Do not panic, if you can believe it, a computer freezes up in the modern world every 40 seconds, which means you will have someone joining you soon. Keep calm and try to figure out what you last did. Tapping on the keyboard and wildly swinging your mouse around will not help the situation much. If your keyboard is still responsive, try to ALT-TAB and see whether you can end the problem program. Usually it would be earmarked with something like 'not responding' tagged to its status on the task bar. If your keyboard is locked up, see whether or not you can move your mouse around. If the answer is a yes, then try to move it to the restart button, or try to right click and shut down some programs.

Well, these are the options that you have if your keyboard and mouse are still functioning. If you are tapping your keyboard and you get a beeping sound, then the entire system has locked you out, meaning Windows has gone into a freeze state that is irreparable. You will have no choice but to find your manual reset button (usually next to the power button on your CPU's tower) and flick your computer back to life. This article is more of a venture into the root of the problem and surveys around the world have revealed a single problem to this one woe of computer users all over the world - the registry of Windows.

What is the registry? The registry is the nexus of the Windows operating system, where all commands are written within its matrix. Windows uses it as a log book of all the activities that happen within the OS as well as an instruction book to execute programs and launch sensitive .DLL and system files. Normally, if all goes well and the registry is intact, bad program launches and system freezes will not happen. But of course, this is not a perfect world, and the computer as well as the end user is not perfect as well. In the end of the day, the registry can get bombarded from many different angles, which include viruses and worms, which infiltrate the registry and leave malicious command lines and false embedded keys inside.

They can also be attacked by malware which has the same effect. Bad program installs and uninstalls can leave negative zero values, orphan keys and bad command lines within its matrix; and these are just some of the problems that can arise. In summary, these bad hats within the registry can and will confuse the Windows operating system, which will lead to problems like crashes and of course systems hangs. The best way to prevent yourself from these problems is for you to get a reliable anti virus, anti malware/spyware program as well as a good registry cleaner. These three in combination will give you a speedy machine with minimal hiccups, leaving you without a situation of what to do when your computer freezes up.

Click Here when your computer does not shut down by itself. Logan Albright helps thousands of people optimize their computers through a proper computer check up. He is an authority on troubleshooting computer problems at http://www.pcaholic.com.

Should I Panic When I See a Windows Registry Error?

2009-02-09T08:48:00.000-08:00

Windows registry errors are pretty common in this day and age, and this is because most of the computer users in the world today are pretty negligent when it comes to maintaining their computer, least of all a tiny file that sits in the core of the Operating System. The problem here lies in the fact that not many of us understand the crucial role of the registry - well that is until the entire computer freezes up and refuses to start up again.

A global meltdown of the computer is a real possibility if the registry is damaged beyond compare and all computer technicians would advise PC users to constantly check up on their registry and clean it up, so that any errors inside would not be compounded and you do not end up in a situation where you lose all your saved work and information in your computer. You should not panic when you see a windows registry error, especially when you see it for the first time. This means that your computer is telling you that there are certain possibilities to why this error happened and I shall give you some of the more common scenarios which can contribute to the registry error.

One is that there is an internal problem with the program that is either running in the background or the one that you are trying to launch. When there are conflicts within the system files or within the registry, an inevitable registry error will popup and the program will not launch. Best case scenario is that the computer will shut down the program and the worst case is your computer will freeze. Also, check your emails or any files you may downloaded. One of the most common problems associated with registry errors are viruses, Trojans, malware and worms.

A firewall is not enough, you need to have a quality anti virus and anti spyware program on your computer. The damage they could do is quite disastrous especially when you have plenty of sensitive information in your computer or maybe data (personal) that you do not want to lose. Viruses and Trojans can infiltrate the registry and start deleting crucial keys and command lines. They could also add in their own command data that might make your computer do things you do not want to. Malware and spyware can leave null values and confusing command lines within the registry, which can cause program crashes or Windows slowing down to a halt.

Also, be wary when you uninstall a program, especially when it crashes half way and you have to manually restart your computer. A bad uninstall can still leave values and keys within the registry SOFTWARE register, which can cause a bit of confusion, especially when your program was supposed to perform a specific function in the OS environment. All of these problems can be easily routed if you download a registry cleaner from the web and do a routine clean up of your registry. There are plenty of good ones available online and getting one is what you should be doing instead of panicking whenever you see a Windows registry error.

Click Here when windows are unable to load registry. Logan Albright helps thousands of people optimize their computers through a proper computer check up. He is an authority on troubleshooting computer problems at http://www.pcaholic.com.

The Best Windows XP Registry Fix

2009-02-09T08:31:00.000-08:00

There is no one best Windows XP registry fix, I think you have plenty of options when it comes to choosing registry cleaners for Windows XP. Hundreds are available online, and it is up to your own inquisitiveness to choose which is the best, weigh their features and in some cases their price - and make that decision to download. Why all the hype about the Windows Registry? Well for many important reasons. The registry was written to simplify the entire computing process, even from the simpler Windows 95 machines that were around not so long ago.

The reason for this is that the amount of data executions that a computer goes through a day is enormous and engineers over at Microsoft realised that they needed an efficient way to track all the activities of the Operating System as well as have a sort of 'instruction guide' for launching the thousands of different configured programs out there. Not to get too technical, there are many shared .DLL or system files that Windows and other programs use to launch themselves, and with the expansion of Flash, Java, Active X and other third party systems, it has gotten pretty complicated.

While it would not be a problem for Windows to 'remember' what goes where, a compartmentalised filing system with all this data would be extremely messy, so engineers needed a consolidated core where all activities of the operating system would be logged in. This would include program installs, uninstalls, removal and installation of hardware, changes to the OS, program updates - you get the picture.

It would also be filled with command line instructions, written in code, of how certain programs are launched. So it would be a sort of a log book as well as a guide Windows can refer to whenever it needs. The problem with having everything in such a vulnerable singular location, is that it is an easy target for nefarious software as well as more prone to the normal wear and tear of computer use.

The flip side of this is that it would be much easier to track where problems came from and repair them with a single tool. Having a registry has its ups and downs, but the philosophy behind it is pretty good. It is an efficient filing system, in one location that maintains the integrity of the OS and everything in it, as well as a memory bank of all activities in the OS.

To maintain its function, you would need to fine tune it and send it for clean up once in a while, because problems in the registry are common and have been linked to some common problems; which include computer hands in XP, slowdowns and even outright crashes. What is the best Windows XP registry fix? The answer lies in the quality of registry cleaner that you get. Looking at the feature list, the ease of use and the history behind the program are guaranteed indications whether or not you have a quality product in your hands.

Increasing Computer Speed the Hassle-Free Way

2009-02-09T08:30:00.001-08:00

We all want to be able to squeeze some extra juice from our computers and today, this write up will talk about how you can go about increasing computer speed the hassle free way. You do not need to spend hundreds and even thousands of dollars on new parts for your computer. If you are looking to eek out just a little more computing horsepower from under the hood, then there are certain things you can do which are cheap and hassle free.

One is to discover the true potential of your CPU and microchip - the heart of the motherboard in your system. Over clocking has become something of an easy past time for computer aficionados all over the world and with software tools and built in OC devices in computers, the hassle and trouble associated with over clocking a computer has literally disappeared. With some thought to extra cooling, anyone can start to ramp up the speed of their computer cores a little at a time. Once you get the hang of it and understand the complexities of your machine through the easy use of an over clocking software, you will be able to increase the performance of your CPU within moments.

Same goes for your graphics card and this is even easier as they come with stock software programs that can increase the speed ob the memory and core clocks with just a flick of a slider. Just remember that cooling is really important; make sure you purchase some cheap fans or ventilate your CPU. Purchase some memory as well, with memory prices becoming more and more affordable for the average consumer, it is a no brainer to increase RAM by a few gigs at a cost of less than $50 dollars. This is an excellent way to increase the computer speed, by giving it more virtual memory to play around with and keep programs running smoothly. On the software side of things, there are certain things you need to take note of. You need to maintain the performance of your OS and computer by doing certain tasks routinely. First and foremost, clean up your computer often as you can; this means deleting unwanted programs and start up software.

Make sure you defragment your hard disks at least once a month; nothing can slow a computer down to a crawl, especially when loading programs than a fragmented hard disk. It takes only a bit of your time, and if you have particularly large hard disks, all you need to do is load up the already available defragmenting software and leave in running for a few hours. Also, invest some money in a good anti virus and anti spyware program, malware and Trojans can not only slow down your computer, but do more harmful things to the sensitive data on it. One last thing you can do is to download a good registry cleaner - maintaining a healthy registry is one of the crucial aspects of a smooth running computer; Windows uses the registry for almost all of its day to day operations.

Click Here to improve computer performance. Logan Albright helps thousands of people optimize their computers through a proper computer check up. He is an authority on troubleshooting computer problems at http://www.pcaholic.com.

3 Simple Solutions on How to Make Your Computer Go Faster

2009-02-09T08:30:00.000-08:00

How to make your computer go faster? Know your computer. That is one of the most important things to take note of when you decide to ramp up the speed, or restore it to its former glory not so many months ago. Information is one of the most important aspects of upgrading or tweaking your CPU and OS. The central processing unit and the operating system are part of a much larger picture; a picture in which you need to know about. What kind of memory are you running? How much? What is the speed of the memory? What about your computer chip?

You should have all this information and more before you decide to do anything and people often slip up and spend gargantuan amounts of money because they did not realise what they had under the hood in the first place. Once you have all the information then you can start to increase the speed of the computer. One of the best ways to do so is to upgrade the memory, because more than likely, you have been installing recent programmes on a machine that was assembled before it was published.

Programmes are pretty scalable, but when too many are installed on a system or if you are working with huge files, you need to ramp up the memory and remove one of the bottlenecks of the system. Memory, especially RAM (or random access memory) is pretty affordable nowadays, even hard disks come pretty cheap. Buying one will solve plenty of problems for you. Another way is for you to defragment your disk. You may have heard this advice somewhere before, but there is a darn good reason why that advice is there in the first place. A fragmented hard drive means that data is strewn about.

This means that to launch a programme, Windows has to go through the motions of re assembling the fragmented data into a coherent code before the programme can launch. This causes massive slowdowns and system hangs even and you need to address this issue pretty quick. It is a good idea to defragment your drive once every 2 to 4 weeks, and this makes sure that you have a speedy hard drive that can launch programmes quick.

Also, the registry is one of the main chokes on a computer system; meaning that the tiny file that resides in your system core has the capability of slowing your system down to a crawl if it is not maintained. Zero values left by programme uninstalls, null values from bad code, corrupt data and command lines left behind by viruses and malware are just some of the examples of how your Windows registry can be left a debilitating mess.

All you need to do is to download a good registry cleaner, which will take care of 100% of these problems and then some. They are pretty advanced nowadays and can even settle clutter from your browsers, system files and trailing debris left behind by bad uninstalls. These are 3 simple solutions on how to make your computer go faster.

What is Trust Model in Public Key Infrastructure

2009-02-09T08:29:00.000-08:00

A trust Model is collection of rules that informs application on how to decide the legitimacy of a Digital Certificate. There are two types of trust models widely used.

- 1. HIERARCHICAL
- 2. WEB-OF TRUST

1. HIERARCHICAL

Hierarchical also called as CA model is the foundation for most of the certification systems. It is also considered as traditional model in use by giant certification authority. In this model certificate users hand over their trust element to CA instead of trying themselves to prove the authenticity of digital certificate. Once you are assured that CA you are dealing with is trust worthy indirectly you are agreeing to trust every other certificate the CA guarantees for.

In Hierarchical trust model CA is at the top level and trust flows from top to bottom way down to the end user. This feature of hierarchical trust model do not burdens end user to prove their authenticity. One important thing to note that CA you trust is cross-certifying another CA's PKI. Hence your system will automatically accept certificates of that CA as well. In practical situation it is advisable to have knowledge of CA`s practices as it will prevent you from accepting certificates from strangers.

2. WEB-OF TRUST

In web-of -trust there is no centralized organization making the decisions. The users themselves decide whom to trust on their personal experiences and knowledge or on suggestions and opinion of other individuals they trust. Web-of-trust are well know for its implementation in PGP.

If someone you already know provides you their public key then it's safe to tell your application that the key is trustworthy. This achieved by signing the key. When other user receives your public key they determine the keys you have signed. Now if they decide to trust you and sign you key, they are in turn tryst you and other entities you trust. This is the way WEB-OF TRUST expands.

The entire process is handled by PGP servers which holds database of keys and the signatures that have been added regularly. Web-of-trust works great for small organizations. Only disadvantage of web-of-trust model is when one user signs bad keys whole group is affected.

Browse more on computer security at http://www.OnlineTechHub.Info

Will Google Chrome Win the Browser War in 2009?

2009-02-09T08:28:00.001-08:00

There are a lot of reviews of 2008 and predictions for 2009 when we step in the New Year. That Google released its own browser Google Chrome ranks in the top 10 software news in 2008, and some experts predicts that Google Chrome will take up a market share of 10%~15% in 2009. Google Chrome is great, but it is not easy to change old routines and make users switch from their current browsers. This prediction will come true or not? We will keep an eye on it.

Google Chrome is a wonderful browser with a simple and clean user interface. It is quite different form IE 8 and FireFox 3. Based on the features of Google Chrome, can it win the browser war in 2009? We will review the special features of Google Chrome. And I have made a demo with DemoCreator to show these features.

One box for everything:
The address bar is also the search box. And it automatically suggests related queries and popular websites based on your input. It is a multifunctional box.
New tab page:
This is not a blank page. It shows us the Links to websites you visit the most, recently closed tabs, and recent bookmarks. It is quite useful for me to find the most visited websites.
Application shortcuts:
This feature enables users to create an easy entry for the special website service.
Dynamic tabs:
For better experience, you can change the tabs position as you want them to be. And Chrome also allows dragging tabs apart, to create separate windows.
Crash control:
If a page breaks in Chrome, it won't take the browser with it, so although you will have to reopen that crashed tab or window, you won't have lost anything else you are doing in other tabs or windows.
Incognito mode:
If you don't want pages you visit to show up in your web history, just choose incognito mode for private browsing. It can protect your privacy.
Safe browsing:
Google Chrome warns you if you're about to visit a suspected phishing, malware or otherwise unsafe website. I was supposed to show you this feature in the demo, but I could not find a sample website like this for a test.
Instant bookmarks:
Chrome simplifies the process of bookmark adding. Just click the star icon at the left edge of the address bar and you have got it done.
Importing settings:
It is easy for you to import your browsing history, saved websites, and passwords from your default browser to Chrome. It reduces the troubles if you switch to Chrome from Firefox or Internet Explorer.
Simpler downloads:
When you download a file from a website, you can your download's status at the bottom of your current window where you can monitor the progress of your downloading file.

There is a new and innovative browser choice for users. Google Chrome does deserve a try.

View the Hight Quality Google Chrome Video from DemoCreator.
Sameshow E-learning Software is dedicated to providing presentation and learning content authoring tools ideal for trade shows, online learning, enterprise training, conference, company presentations etc.
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Virtual Private Network

2009-02-09T08:28:00.000-08:00

The word 'Technology' has it's origins from Greek. Technology is a result of science and engineering. It is the manner adopted by humans to improve their surroundings.

One of the method involved is - making use of tools and machines to carry out tasks efficiently. With time we have observed rapid growth and change in technology like PCS, podcasts, teleconferencing, videoconferencing, electronic teaching centers, etc. One amongst the several technologies is the Virtual Private Network.

A VPN is a private network that uses a public network like the internet to connect remote sites and users. A VPN uses "virtual" connections routed through the internet from the company's private network to the remote site or employee.

A public network like the internet can help carry VPN traffic based on certain standard protocols. A Service Level Agreement (SLA) between the VPN customer and the VPN service provider is drawn in order to enable the existence of a service providers private network.

Advantages of a VPN:

* Improved security and productivity

* Simplified network topology

* Reduced operational and transportation costs

* Faster Return on Investment

* Extensive connectivity across the globe

Features:

* Reliable

* Secure

* Scalable

* Network and policy management

Types of VPN:

1. Remote Access VPN

2. Intranet VPN

3. Extranet VPN

1. Remote Access VPN:

Remote access VPN is a user-to-LAN (Local Area Network) connection used by an organization whose employees need to connect to the private network from remote locations.

The remote access VPN helps save on costs over toll free expenditure and is secure (encrypted tunnels across a public network like the internet), scalable

2. Intranet VPN (Interconnecting corporate sites):

The intranet VPN helps in cost saving over dedicated, leased lines. There exist tunneled connections and encryption that enables reliable throughput.

3. Extranet VPN (connecting corporate site(s) to external business partners or suppliers)

Extranet VPN extends WAN (Wide Area Network) to business partners.

VPN Security:

The most important part of a VPN solution is security. A VPN helps putting private data on public networks and this raises concerns about threats to that data and the impact of data loss. A Virtual Private Network must provide security services in area of Authentication.

Authentication ensures that a user or system is who the user claims to be. Security is thus ensured.

Authentication Mechanisms:

* login name, password, PIN (password - specified number of digits followed by 8 bits that constantly changes at regular intervals)

* a computer readable token like a smart card

* fingerprint, retinal or iris pattern

Tunneling:

Tunneling is a very important part of a VPN. Tunneling involves placing a packet within another packet and sending it over a network. The network (like the internet) over which the packet is sent and the *tunnel interface understand the protocol of the outer packet.

Protocols used in Tunneling:

* Carrier protocol - The protocol used by the network that the information is traveling over

* Encapsulating protocol - The protocol (GRE, *IPSec, L2F, PPTP, L2TP) that is wrapped around the original data

* Passenger protocol - The original data (IPX, NetBeui, IP) being carried

Example: A packet that uses a protocol not supported on the internet like NetBeui can be placed inside an IP packet and can be sent safely over the internet.

Considering the current business scenario/trend that involves increased commuting/telecommuting and widely spread global operations, with employees who need to connect to central resources from remote sites in order to communicate with each other, technologies like the VPN prove to be very handy and vital.

*Tunnel Interface: The two points where the packet enters and exits the network.

*IPsec is the security portion of the IP standard that is supported by the Client. IPsec performs packet-by-packet authentication and end-to-end encryption. In addition, IPsec supports the IP within IP encapsulation for network address translation.

Getting Going With Cisco Router Simulators

2009-02-09T08:27:00.000-08:00

For anyone who has ever needed to test a new network architecture, implement a new routing protocol or simply study for a Cisco exam has needed access to a real live router or a router simulator. But buying a bunch of routers just test up an idea or for study is expensive. And until recently good fully functional router simulators we just something we could only dream about.

Some company's, like Boson have router simulators you could buy to help you study for the CCNA but it was extremely limited with limited functionality. There was also some open source software like dynmips and the hypervisor engine that could be used to simulate a router but these applications were really difficult to configure and only support limited models.

Well now there is GNS3 - a multi-platform Graphical Network Simulator. GNS3 builds on dynamips and dynagen to create a nice graphical front end for building complex Cisco networks. I was completely amazed at how easy it was to install and build a new network, configure routers and switches and have a nice simulated network up and running.

GNS3 is a free open source router emulation software application developed in Python and uses the PyQT libraries for creating the UI. It uses standard vector graphics similar to Visio to create the network digrams and layouts. GNS3 uses real Cisco IOS for creating fully function emulated routers and switches.

GNS3 supports many types of interface configurations (pretty much if its in the IOS its supported). Frame Relay, Frame Relays Switches, ATM, Ethernet, OSPF, EIGRP, BGP, and more.

The only draw back that I can say so far with GNS3 is that you need a pretty hefty machine to simulate a large network. Especially if you are trying to build it on a Windows machine. I havent tried but I have heard that running GNS3 on linux is much more manageable.

Another application that has similar functionality is Cisco's Packet Tracer. Thought originally designed as a group learning tools for Cisco Academy students, it make for a nice router simulator. And because its build for Cisco Academy, the only place to get it is if your enrolled in Cisco Academy. Another problem with Packet Tracer is it only runs on Windows. It's a bit more limited than GNS3, as it comes preconfigured with set models of routers and switches. It is very stable and less resource intensive than GNS3 by a long shot and will do the trick when you need to test out a quick config. To find Packet Tracer is pretty easy if you look out on the bit torrents, you should easily be able to find it.

So if your looking for a cool router simulator and have been frustrated thinking they dont exist. Think again! Here are two really cool simulators right here!

Should We Trust Technology?

2009-02-09T08:26:00.002-08:00

I was helping a friend fix his computer, he asked is everything lost? I ask him if he backed up his data, of course not why would he do that? I asked the next question, when was the last time you backed-up your data? Then like he had a megaphone in my ear, I DON"T KNOW HOW TO BACK UP MY DATA! All my spreadsheets and word documents are lost, how can that be the computers brand new?

If I had a dollar for every computer that broke down out of the box I wouldn't have to worry about money. But for some reason when we buy something we just assume it will work for ever, especially things like TVs, stereos, freezers and computers. We put more faith in those purchases than we do in anything else, well, outside of eating in a public restaurant anyway. Why? Why do we do that? Nowhere does it say these devices and equipment won't breakdown or already be broken before we even get them installed. Most things we buy today all have some form of technology in them, try and think of one that doesn't...well a potato peeler maybe but there's not many.

There seems to be this unwritten law that if I buy something it just works, there's no chance it won't we're thinking as we drive home. I have sold more computers than I can count over the years and manufacturer's don't always get it right, something can fall through the cracks. Assembly lines are not immune to malfunction, why? Technology!

I got a call to provide some input on what was thought to be a DNS issue, after asking enough questions, two or three I discovered that most likely it was that expensive high end Router that was installed. I said pull it and go get something different and see what happens. You guessed it, that high end router was faulty.

We put a lot of faith in technology, we build spreadsheets thinking that they are accurate and the software can't make a mistake, really? How do you know? Society has gone down the technology road so far now we can go back, and would we want to? Most of us have High Speed (Broadband) Internet connections, would you go back to dial-up now? I rest my case.

Now technology is progressing at a rate that is exponential, explosive growth. People think linearly, one, two, three, and 30 steps later your at 30. But the reality of information technology it is going 2, 4, 8, 16, and 30 steps later you are at a billion! With growth moving that quickly how will ensure that it is accurate and not faulty?

Take nanotechnology, little blood cell sized nanobots will be injected into our blood streams and cure say diabetes. Will it? What if doesn't, what are the side effects and who is going to guarantee that nanobots are full proof? I suspect no one will back them up 100% but how can we be sure these technologies will work 100% of the time and not fail in the future?

I believe there needs to be a body that overseas and sets standards to protect us against faulty technology in the future, in light of this exponential growth curve. You may assume that there will be, but, let's not assume please. So, should we trust technology? Some of it? Yes. A Lot of it? Yes. But when it comes to injecting blood cell sized nanobots into our bodies, I want to know for sure something won't go wrong. How far do we allow technology to go, to intrude on our privacy and watch over us? How deep is your trust in technology?

I'm just asking the questions nothing more. I'm suggesting we keep things in perspective, make sure we put the proper framework in place now to ensure the safe use of these new technologies being worked on today.

Getting Going With Cisco Router Simulators

2009-02-09T08:26:00.001-08:00

GNS3 supports many types of interface configurations (pretty much if its in the IOS its supported). Frame Relay, Frame Relays Switches, ATM, Ethernet, OSPF, EIGRP, BGP, and more.

So if your looking for a cool router simulator and have been frustrated thinking they dont exist. Think again! Here are two really cool simulators right here!