Synthetics

Synthetics

Most of the products and materials we use today are of synthetic origin; from the garments we wear to the rubber used in the production of various tools। This article briefly discusses some examples of synthetics.

Synthetic Fibres

Synthetic fibres are "man-made textile fibres produced entirely from chemical substances, unlike those man-made fibres derived from such natural substances as cellulose or protein." The polymers of synthetic fibres do not occur in nature, instead, they are produced from scratch in chemical plants or laboratories, "almost always from by-products of petroleum and natural gas." Of these polymers are nylon, polyethylene terephthalate, as well as other compounds such as the acrylics, the polyurethanes and polypropylene. Synthetic fibres are "spun and woven into huge consumer and industrial products", from garments such as shirts and scarves, home furnishings such as carpets ad drapes, to industrial parts such as flame-proof linings and drive belts.

Stages in the wet spinning of polymeric fibres

Stages in the melt spinning of polymeric fibres

Examples of textured yarns

Table 1: Properties & Applications of Prominent Synthetic Fibres

Synthetic Abrasives

"Abrasives are sharp, hard materials used to wear away the surface of softer, less resistant materials." Examples of abrasives range from the soft particles used in household cleansers and jeweler's polish to the hardest known material, the diamond. The forms in which abrasives are used include grinding wheels, sandpapers, honing stones, polishes, cutoff wheels, tumbling and vibratory mass-finishing media, sandblasting, pulpstones, ball mills, and other tools and products. "Only through the use of abrasives is industry able to produce the highly precise components and ultrasmooth surfaces required for the manufacture of automobiles, airplanes and space vehicles, mechanical and electrical appliances, and machine tools." The most important characteristics that should exist in an abrasive are hardness and toughness or strength. It was proved that a certain degree of control over the characteristics of synthetic abrasives could be achieved by various methods, to develop abrasives that would "meet the operating conditions found in a variety of applications."

Table 2: Hardness of Prominent Synthetic Abrasive Materials

The Verneuil Process

The Verneuil process -also referred to as the Flame-Fusion Process, is a method by which synthetic rubies and sapphires are produced. It was originally developed in 1902 by a French chemist, Auguste Verneuil. By applying slight modifications to this method, spinel, rutile and strontium titanate can be produced. Star rubies and sapphires were first developed in 1947 in the United States. "The synthetic gems have sharper and more distinctly developed stars than the natural crystals", which is why they are superior to natural gemstones.

Synthetic Food Additives

Food additives are produced for the purpose of enhancing sensory characteristics of foods, that are subject to degradation or loss during food processing. Food additives include colouring agents, flavourings and sweeteners.

Synthetic Colorants: "Synthetic colorants are primarily petroleum-based chemical compounds", unlike natural colorants that are derived from plants, animals and mineral sources. Synthetic colorants exist in the forms of powders, pastes, granules or solutions. The fact that synthetic colorants can be modified gives them superiority to natural colorants that are associated with certain problems, including "the lack of consistent colour intensities", instability under special conditions and "reactivity with other food components".

Flavourings: The flavour of foods is influenced by their taste and smell (odour). Flavour additives form the largest group among food additives. Those of synthetic origin are mixtures of synthetic compounds, whereas natural flavourings are extracted from plants, animals, spices and herbs.

Sweeteners: Since the discovery of saccharin -the first synthetic sweetener- in the late 1800s, efforts have been carried out to develop other synthetic sweeteners that provide few or no calories or nutrients. These are thus referred to as "nonnutritive sweeteners", unlike the natural sweeteners such as sucrose, glucose, fructose....etc. that are known as "nutritive sweeteners" for the energy they provide in the form of carbohydrates. Synthetic sweeteners are used in the manufacture of low-calorie products. They also serve persons with diabetes as a carbohydrate replacement.

Synthetic Chemical Agents

Synthetic chemical agents are used to treat bacterial diseases. Examples of them include the sulfonamides; used for treating urinary tract infections, preventing infection of burns as well as certain forms of malaria, isoniazid, ethabutol, pyrazinamide and ethionamide; useful in treating tuberculosis.

Synthetic Rubber

Rubber is made of elastic polymers, which are "materials composed of long, chainlike molecules that are capable of recovering their original shape after being stretched to great extents." The molecules of rubber stretch in the direction in which they are pulled and upon release, they return to their state that existed before the application of force. Rubber is used in the manufacture of automobile tyres, mountings, gaskets, belts, hoses and consumer products such as shoes, clothing, furniture and toys. Natural rubber nowadays competes with synthetic rubber such as styrene-butadiene rubber and polybutadiene, which are extracted from the by-products of petroleum and natural gas.

Nuclear Energy

Nuclear Energy

"Nuclear Energy is the safest, cleanest, cheapest, and most efficient type of energy." It supplies about 17% of the world's electricity. Nowadays, it has become an issue in a major debate as to whether such type of energy ought to be disposed of, or continued to be used and developed while disregarding its disadvantages.

What is Nuclear Energy?

The structure of the nucleus of an atom can undergo changes. Such changes are called "nuclear reactions". The form of energy produced in a nuclear reaction is referred to as "nuclear energy" or "atomic energy". Nuclear energy is either produced by "nuclear fission" (in which large nuclei are split to release energy) or by "nuclear fusion" (in which small nuclei are combined to release energy). The atomic bomb and nuclear reactors in nuclear plants work on the principle of nuclear fission, where the element uranium (isotope U-235) is used to undergo fission. Stars produce their heat and light through nuclear fusion. The hydrogen bomb operates by nuclear fusion as well.

Advantages

• Speaking in terms of limited supplies of energy, nuclear energy is the most efficient alternative to coal, oil and natural gas, which are on their way of becoming scarce.

• Nuclear energy has environmental benefits. It is a pure form of energy, the production of which doesn't involve the burning of fossil fuel in no way whatsoever.

• Uranium fuel -upon which nuclear power plants run- contains much more concentrated energy than any other fuel. It is estimated that one pound of uranium can produce as much electricity as 12,000 pounds of coal and 1,200 gallons of oil. Therefore, nuclear power plants consume less amounts of fuel than needed by those which burn other fuels, and at the same time they produce additional amounts of electricity, making countries' economies grow.

• Nuclear fuel is less costly than other fuels.

• For countries that rely on foreign oil suppliers, nuclear energy is good news, for it cuts their demands for imported oil.

Disadvantages

• Reactor meltdowns -where the nuclear fission reaction accidentally goes out of control- result in the occurrence of nuclear explosions. A famous reactor meltdown incident took place in Russia's Chernobyl nuclear power plant, where radiation escaped from the reactor to which many lives were exposed. Many died in the following days and others in the following years.

• Nuclear explosions cause the emission of massive amounts of harmful radiation. Living organisms exposed to nuclear radiation are subject to life-threatening diseases.

• Nuclear waste produced by nuclear reactors- is difficult to be disposed of. Nuclear waste emits harmful radiation that causes harm to living organisms.

Nuclear Weapons

Nuclear weapons, examples of which include the atomic bomb and the hydrogen bomb, are major threats in the field of nuclear physics. It is estimated that the amount of nuclear weapons that exist in the world today is sufficient enough to kill everyone. Those who argue in favour of nuclear weapons believe that they are essential for ensuring security and safety. Indeed, this is true. However, stricter methods should be adopted to control their use.If a nuclear war breaks out, the resultig damage would surely be devastating. We definitely don't want incidents like those which took place in Hiroshima and Nagasaki to occur again.

The Future of Nuclear Energy

Nuclear power plants will undergo major development, making them faster and less costly to build, better performing and safer to the environment and its inhabitants. A convenient solution to the problem of the disposal of nuclear waste will be found. More countries will sign the Nuclear Non-Proliferation Treaty and until then stricter methods will be applied to minimize the likelihood of the use of nuclear weapons. These aren't but a few attempts to make the world a safer place for all, and a better environment where Man is able to prosper and develop.

Ballistics Science

Ballistics Science

When a forensic investigation involves a shooting, ballistics becomes an important facet of the investigation. Ballistics is a term that refers to the science of the flight path of a bullet. The flight path includes the movement of the bullet down the barrel of the firearm following detonation and its path through both the air and the target.
Tracing the path of a bullet is important in a forensic examination. It can reveal from what direction the bullet was fired, which can be vital in corroborating the course of events in the crime or accident.

Once a bullet leaves the rifle or gun barrel, the aforementioned frictional and gravitational forces begin It is an obvious truism that the distance that a bullet can travel depends on its speed. A higher speed imparts more energy to the bullet. The frictional resistance of the air and the downward pull of gravity will take longer to slow the bullet's flight, as compared to a bullet moving at a lower initial velocity.

Generally, a bullet fired from a rifle will carry more energy than a bullet fired from a handgun. This is because the stronger firing chamber of a rifle is able to withstand the increased explosive power of a larger quantity of powder that would likely rupture the barrel of the handgun. Detonation of the powder in a rifle or handgun supplies the thrust to propel the bullet down the barrel.
Expansion of the exploding gunpowder generates pressure, which is measured as the force of the explosion that pushes on the area of the bullet's base. This area is essentially the diameter of the barrel of the firearm, which remains constant. Thus, the explosive energy that passes to the bullet depends on the mass of the bullet multiplied by the force of the explosion multiplied by the time that the force is applied (i.e., the time the bullet is in the barrel). A longer barrel will produce a faster moving bullet.

to slow its speed, producing a downward arc of flight. The frictional force is affected by the bullet's shape. A blunt shape will present more surface area to the air than will a very pointed bullet.

Another factor that affects the flight of a bullet is called yaw. As in an orbiting spacecraft or a football tossed through the air, yaw causes a bullet to turn sideways or tumble in flight. This behavior is decreased when the object spins as it moves forward (the spiraling motion of a football). The barrel of a rifle or gun contains grooves that cause the bullet to spin. More damage results from a bullet that is tumbling rather than moving in a tight spiral.
The shape of a typical bullet—much like a football with one end blunt instead of tapered—is a compromise that reduces air resistance while still retaining the explosive energy that allows the bullet to damage the target.

The composition of a bullet is also important. Lead is commonly used to form the core of bullets. However, because it tends to deform, the blending in of other metals (typically antimony and copper) produces a bullet that can withstand the pressure of flight and impart high energy to the target upon impact.

Copper is often used to jacket the inner lead core of a bullet. However, some bullets are deliberately made without this full metal jacket. Instead, the bullet has a tip made of lead or a tip that is hollow or very blunt. These bullets deform and break apart on impact, producing more damage to the target than is produced by a single piece of metal. This is because the bullet's energy is dissipated within a very short distance in the tissue.
Forensic and medical examiners are able to assess the nature of tissue damage in a victim and gain an understanding of the nature of the bullet used.

A bullet produces tissue damage in three ways. First, a bullet can shred (lacerate) or crush tissue or bone. Bullets moving at relatively low velocity do most of their damage this way. Fragmentation of bone can cause further damage, as the bone shards themselves become missiles.

The second form of damage is known as cavitation. This damage is produced by the forward movement of air or tissue in the wake of the bullet. The wound that is produced by the bullet is destructively broadened by the force of the moving air or tissue. In a tissue, this produces even more structural damage.

Third, the air at the front and sides of a very fast moving bullet can become compressed. The explosive relaxation of the compression generates a damaging shock wave that can be several hundred atmospheres in pressure. Fluid-filled organs such as the bladder, heart, and bowel can be burst by the pressure.

Recovery of bullets can be a very useful part of forensic ballistics. A variety of bullet designs exist, some that are specific to the firearm. Furthermore, the scouring of a bullet's surface as it encounters the grooves of the firearm barrel can produce a distinctive pattern that enables a bullet to be matched with the firearm. A weapon recovered from a suspect can be test fired and the bullet pattern compared with a bullet recovered from the scene to either implicate or dismiss involvement of the firearm in the crime.
This aspect of ballistics was crucial in convicting John Allen Muhammad and John Lee Malvo of the 10 sniper murders and the wounding of three others in the Washington, D.C. area that occurred during three weeks in October of 2002.

Psychotherapy

Psychotherapy


Psychotherapy a set of techniques believed to cure or to help solve behavioraland other psychological problems in humans. The common part of these techniques is direct personal contact between therapist and patient, often in the form of talking.

Psychotherapy, or personal counselling with a psychotherapist, is an intentional interpersonal relationship used by trained psychotherapists to aid a client or patient in problems of living.

It aims to increase the individual's sense of their own well-being. Psychotherapists employ a range of techniques based on experiential relationship building, dialogue, communication and behavior change and that are designed to improve the mental health of a client or patient, or to improve group relationships (such as in a family).

Psychotherapy may also be performed by practitioners with a number of different qualifications, including psychiatry, clinical psychology, counseling psychology, mental health counseling, clinical social work, marriage and family therapy, rehabilitation counseling, music therapy, occupational therapy, psychiatric nursing, psychoanalysis and others.

Indeed, psychotherapy can increasingly be considered as a profession in its own right, and in Europe the European Association for Psychotherapy is promoting this view and has set professional training standards to this effect. However, some European countries have passed laws about psychotherapy that restrict its practice to the professions of psychology and psychiatry; Austria has a law that recognizes multi-disciplinary approaches; other European countries have not yet regulated psychotherapy. In the United Kingdom, psychotherapy is voluntarily regulated by the United Kingdom Council for Psychotherapy.

Einstein for scientist or a Bryan act ?

what do you think Einstein for scientist or a Bryan act ? think againhe was the advance physicist ,great noblest and he was the key maker tothe haven as you called it .how was he noblest not for the noble prizefor the great science noble which hold the key to heaven and make youto evolve faster to be your ultimate vi...sion god (your cravingpower).he is only not known for his book theory of relativity,or theformula E=mc2 (consider it square ) your advance tv,yourcellphone,gps,satellite all share his key not only that is was masterof abstracting microscopic DNA from a king size palace for solving mostdifficult cases and you computer is about to be changed to from 0 tohero with more GB more ram and faster processing 100 times better thanyou can even imagine,by the theory that proton can be at in twoplaces at once imagine you were the protons this all is derived fromhis great nobles and computer no longer need binary digits tofunction.He was some times mistaken this doesn't means that he was wrongthis means he opened new hints for making you understand thing better.next time Stephan Hawking child of Einstein.

Written by Khom Bhattarai

bio-desel

Bio-Disel(B20)

Its like disel but it is more Volitile(more than Water). We can call it B20. It can be easily created in our locality. The process involved are:-

• Oil or Fat + Sodium Hydroxide(NaoH)
• Grinding for 5-10 minutes
• Filtration through Cotton clothes. Then Pure biodisel is obtained.

It is volatile than water or any other Petrelium product. We need 20% pure disel to make Bio-Disel. i.e 80%biodisel + 20% pure disel.

Characterstic

• Efficient than Petrole Disel

i.e. Petrole disel= 68% , Bio-disel= 78%

• Less mobile needed to a disel enjeen.
• Longlivity of an enjeen.