МИНИСТЕРСТВО ОБРАЗОВАНИЯ И НАУКИ РЕСПУБЛИКИ КАЗАХСТАН
Западно-Казахстанский аграрно-технический университет имени Жангир хана
Материалы для самостоятельной работы
по дисциплине «Английский язык»
модуля М-3 коммуникативный
для студентов 2 курса политехнического факультета
специальностей 5В071300 – «Транспорт, транспортная техника и технология», 5В080600 – «Аграрная техника и технология», 5В090100 – «Организация перевозок, движения и эксплуатация транспорта», 5В071800 – «Электроэнергетика», 5В071600 – «Приборостроение», 5012000 – «Профессиональное обучение», 5В073100 – «Безопасность жизнедеятельности и окружающей среды», 5В070300 – «Информационные системы», 5В090700 – «Кадастр», 5В090300 – «Землеустройство»
форма обучения очная
на 3 семестр 2014-2015 учебного года
Уральск – 2014
Составители: Муханбеткалиева Г.Ш., Джумагулова С.К.
Кафедра «Иностранные языки»
Машиностроительный факультет. Ауд. № 308, 309
Количество кредитов – 2
СРОП – 15 часов
СРО – 45 часов
Обсужден на заседании кафедры «____» _____2014г. Протокол№ _____
George Henry Corliss (June 2, 1817 – February 21, 1888)was an American mechanical engineer and inventor, who developed the Corliss steam engine, which was a great improvement over any other stationary steam engine of its time. The Corliss engine is widely considered one of the more notable engineering achievements of the 19th century. It provided a reliable, efficient source of industrial power, enabling the expansion of new factories to areas which did not readily possess reliable or abundant water power. Corliss gained international acclaim for his achievements during the late 19th century and is perhaps best known for the Centennial Engine, which was the huge centerpiece of the 1876 Centennial Exposition in Philadelphia.
Brayton's Ready MotorIn 1872 Brayton patented a two-stroke kerosene stationary engine known as Brayton's Ready Motor, which had one cylinder for compression, a combustion chamber, and a separate cylinder in which the products expanded for the power stroke. It bore a marked resemblance to a steam engine with its rocking beam and flywheel. His engine needed no spark plug - it had a continuously burning flame to ignite each cycle of the engine. He demonstrated that prolonging the combustion phase of the cycle, by injecting fuel at a controlled rate, produced more power per unit of fuel consumed. However, much of the efficiency gained by this method was lost due to the lack of an adequate method of compressing the fuel mixture prior to ignition.Brayton's engine was displayed at the Centennial Exposition in Philadelphia in 1876 and for a few years was well regarded, but within a short time the Otto engine became more popular. However, it was considered the first safe and practical oil engine and also served as inspiration to George B. Selden.A Brayton Engine is preserved in the Smithsonian in the American History museum, and a later Brayton engine which powered one of John Philip Holland's early submarines is preserved in the Paterson Museum in the Old Great Falls Historic District of Paterson, New Jersey.
George Stephensonwas a British inventor and engineer. He is famous for building the first practical railway locomotive.
Stephenson was born in 1781 in Wylam, near Newcastle upon Tyne, Northumberland. During his youth he worked as a fireman and later as an engineer in the coal mines of Newcastle. He invented one of the first miner's safety lamps independently of the British inventor Humphrey Davy. Stephenson's early locomotives were used to carry loads in coal mines, and in 1823 he established a factory at Newcastle for their manufacture. In 1829 he designed a locomotive known as the Rocket, which could carry both loads and passengers at a greater speed than any locomotive constructed at that time. The success of the Rocket was the beginning of the construction of locomotives and the laying of railway lines.
Robert Stephenson, the son of George Stephenson was a British civil engineer. He is mostly well-known known for the construction of several notable bridges.
He was born in 1803 in Willington Quay, near Newcastle upon Tyne, and educated in Newcastle and at the University of Edinburgh. In 1829 he assisted his father in constructing a locomotive known as the Rocket, and four years later he was appointed construction engineer of the Birmingham and London Railway, completed in 1838. Stephenson built several famous bridges, including the Victoria Bridge in Northumberland, the Britannia Bridge in Wales, two bridges across the Nile in Damietta in Egypt and the Victoria Bridge in Montreal, Canada. Stephenson was a Member of Parliament from 1847 until his death in 1859.
James Watt, James Prescott Jaulle
James Watt was born on 19 January 1736 in Greenock, Renfrewshire, a seaport on the Firth of Clyde. His father was a shipwright, ship owner and contractor, and served as the town's chief baillie, while his mother, Agnes Muirhead, came from a distinguished family and was well educated. Both were Presbyteriansand strong Covenanters. Watt's grandfather, Thomas Watt, was a mathematics teacher and baillieto the Baron of Cartsburn.
Watt did not attend school regularly; initially he was mostly schooled at homeby his mother but later he attended Greenock grammar school. He exhibited great manual dexterity, engineering skills and an aptitude for mathematics, while Latinand Greekfailed to interest him.
When he was eighteen, his mother died and his father's health began to fail. Watt travelled to London to study instrument-making for a year, then returned to Scotland, settling in the major commercial city of Glasgowintent on setting up his own instrument-making business. He made and repaired brass reflecting quadrants, parallel rulers, scales, parts for telescopes, and barometers, among other things. Because he had not served at least seven years as an apprentice, the Glasgow Guildof Hammermen (which had jurisdiction over any artisansusing hammers) blocked his application, despite there being no other mathematical instrument makers in Scotland.
Watt was saved from this impasse by the arrival of astronomical instruments to the University of Glasgowthat required expert attention. Watt restored them to working order and was remunerated. These instruments were eventually installed in the Macfarlane Observatory. Subsequently three professors offered him the opportunity to set up a small workshop within the university. It was initiated in 1757 and one of the professors, the physicistand chemistJoseph Black, became Watt's friend.
At first he worked on maintaining and repairing scientific instruments used in the university, helping with demonstrations, and expanding the production of quadrants. In 1759 he formed a partnership with John Craig, an architect and businessman, to manufacture and sell a line of products including musical instruments and toys. This partnership lasted for the next six years, and employed up to sixteen workers. Craig died in 1765. One employee, Alex Gardner, eventually took over the business, which lasted into the twentieth century.
1764, Watt married his cousin Margaret (Peggy) Miller, with whom he had five children, two of whom lived to adulthood: James Jr. (1769–1848) and Margaret (1767–1796). His wife died in childbirth in 1772. In 1777 he married again, to Ann MacGregor, daughter of a Glasgow dye-maker, with whom he had two children: Gregory (1777–1804), who became a geologist and mineralogist, and Janet (1779–1794). Ann died in 1832. Between 1777 and 1790 he lived in Regent Place, Birmingham.
James Prescott Jaulle
The son of Benjamin Joule (1784–1858), a wealthy brewer, and Alice Prescott Joule, James Prescott Joule was born in the house adjoining the Joule Brewery in New Bailey Street, Salford 24 December 1818. James was tutored at the family home 'Broomhill', Pendlebury, near Salford, until 1834 when he was sent with his elder brother Benjamin, to study with John Dalton at the Manchester Literary and Philosophical Society. The pair only received two years' education in arithmeticand geometrybefore Dalton was forced to retire owing to a stroke. However, Dalton's influence made a lasting impression as did that of his associates, chemistWilliam Henry and Manchester engineers Peter Ewart and Eaton Hodgkinson. Joule was subsequently tutored by John Davies. Fascinated by electricity, he and his brother experimented by giving electric shocks to each other and to the family's servants.
Joule became a manager of the brewery and took an active role until the sale of the business in 1854. Science was a hobby but he soon started to investigate the feasibility of replacing the brewery's steam engines with the newly invented electric motor. In 1838, his first scientific papers on electricity were contributed to Annals of Electricity, the scientific journal founded and operated by Davies's colleague William Sturgeon. He formulated Joule's laws in 1840http://en.wikipedia.org/wiki/James_Prescott_Joule - cite_note-4 and hoped to impress the Royal Society but found, not for the last time, that he was perceived as a mere provincial dilettante. When Sturgeon moved to Manchester in 1840, Joule and he became the nucleus of a circle of the city's intellectuals. The pair shared similar sympathies that science and theology could and should be integrated. Joule went on to lecture at Sturgeon's Royal Victoria Gallery of Practical Science.
He went on to realise that burning a pound of coal in a steam engine produced five times as much duty as a pound of zincconsumed in a Grove cell, an early electric battery. Joule's common standard of "economical duty" was the ability to raise one pound by a height of one foot, the foot-pound.
Joule was influenced by the thinking of Franz Aepinus and tried to explain the phenomena of electricity and magnetismin terms of atomssurrounded by a "calorificetherin a state of vibration".
However, Joule's interest diverted from the narrow financial question to that of how much work could be extracted from a given source, leading him to speculate about the convertibility of energy. In 1843 he published results of experiments showing that the heatingeffect he had quantified in 1841 was due to generation of heat in the conductorand not its transfer from another part of the equipment. This was a direct challenge to the caloric theory which held that heat could neither be created nor destroyed. Caloric theory had dominated thinking in the science of heat since it was introduced by Antoine Lavoisier in 1783. Lavoisier's prestige and the practical success of Sadi Carnot's caloric theory of the heat engine since 1824 ensured that the young Joule, working outside either academiaor the engineering profession, had a difficult road ahead. Supporters of the caloric theory readily pointed to the symmetry of the Peltier-Seebeck effect to claim that heat and current were convertible, at least approximately, by a reversible process.
M.V.Lomonosov (1711-1765)was a famous Russian writer, chemist and astronomer who made a lot in literature and science. Lomonosov was born on November 19, 1711 in Denisovka, near Archangelsk, and studied at the University of the Imperial Academy of Sciences in St. Petersburg. After studying in Germany at the Universities of Marburg and Freiberg, Lomonosov returned to St. Petersburg in 1745 to teach chemistry and built a teaching and research laboratory there four years later.
Lomonosov is often called the founder of Russian science. He was an innovator in many fields. As a scientist he rejected the phlogiston theory of matter commonly accepted at the time and he anticipated the kinetic theory of gases. He regarded heat as a form of motion, suggested the wave theory of light and stated the idea of conservation of matter. Lomonosov was the 1st person to record the freezing of mercury and to observe the atmosphere of Venus.
Interested in the development of Russian education, Lomonosov helped to found Moscow State University in 1755, and in the same year he wrote a grammar that reformed the Russian literary language by combining Old Church Slavonic (церковно-славянскийязык) with modern language. In 1760 he published the 1st History of Russia. He also revived the art of Russian mosaic and built a mosaic and colored glass factory. Most of his achievements were unknown outside Russia. Ha dead in St. Petersburg on April 15, 1765.
D.I.Mendeleyev (1834-1907) is a famous Russian chemist. He is best known for his development of the periodic table of the properties of the chemical elements. This table displays that elements’ properties are changed periodically when they are arranged according to atomic weight.
Mendeleyev was born in 1834 in Tobolsk, Siberia. He studied chemistry at the University of St. Petersburg and in 1859 he was sent to study at the University of Heidelberg. Mendeleyev returned to St. Petersburg and became Professor of Chemistry at the University of St. Petersburg in 1866. Mendeleyev was a well-known teacher and because there was no good text-book in chemistry at that time, he wrote two-volume “Principles of chemistry” which became a classic text-book in chemistry. In 1869 he published his 1st version of his periodic table of elements. In 1871 he published an improved version of the periodic table, in which he left gaps for elements that were not known at that time. His table and theories were proved later when three predicted elements: gallium, germanium and scandium were discovered.
Mendeleyev investigated the chemical theory of solution. He found that the best proportion of alcohol and water in vodka is 40%. He also investigated the thermal expansion of liquids and the nature of petroleum. In 1893 he became director of the Bureau of Weights and Measures (Палатамервесов) in St. Petersburg and held this position until his death in 1907.
MATERIAL SCIENCE AND TECHNOLOGY
Fatigue (materials), in metals, progressive deterioration, that ultimately results in the breaking of the metal. Fatigue is caused by repeated application of stress to the metal, and the deformation of a material or object as a result of the stress is known as creep. The fatigue strength of a typical steel alloy is about 50 percent of the ultimate strength and 75 percent of the elastic strength but may be considerably lower, particularly for the strongest heat-treated steels. If the elastic strength of a steel beam is about 45,000 kg (about 100,000 lb), it could withstand a continuous stress of about 41,000 kg (about 90,000 lb) for centuries, with no measurable yielding. A stress of about 36,000 kg (about 80,000 lb) alternately applied and withdrawn, however, would probably cause fatigue failure after a few million applications. Fatigue is not important in civil engineering structures, in which stress is generally continuous, but in an engine turning at 3000 rpm, any stress to which an engine part is subjected will often be applied millions of times within a few hours of operation. Fatigue failures account for an overwhelming majority of all structural failures in cyclic devices such as engines, and design engineers must consider fatigue strength, rather than elastic strength or ultimate strength, in their calculations.
The problem of metal fatigue has gained great importance in the field of air transport since the end of World War II. The increased stresses of high-speed flight with heavy loads at high altitudes have posed difficult problems for structural engineers, especially in wing and engine design. The exact structural changes that occur as a result of fatigue are not known. The failure usually starts at a point of stress concentration and proceeds along the intercrystalline planes of the metal. The break often shows a characteristic coarsely crystalline structure except where the surfaces are worn smooth by rubbing against one another after the break has started. The term fatigue is not an entirely appropriate one, because no amount of rest between stress applications has any measurable effect upon the ultimate failure.
One of new synthetic materials used widely is plastic. Although the first plastic, celluloid was introduced 100 years ago. Some types of plastics are very tough, e. g nylon. Others may be relatively brittle, as polystyrene. Plastic is not as strong as iron or steel or concrete when it comes to supporting great weights. Plastics do not rust and therefore require no protective layer, such as paint, which can subsequently peel off. They can be colored and such color is part of material. some types will withstand higher temperatures than others and the ceiling temperature is constantly being raised as new varieties appear. Plastics have found wide application both in everyday life and in industry.
It is a decorative plastic-laminate. It consists of paper filler impregnated with thermosetting resins, on top of which is laid similarly impregnated paper itself is topped with a melamine resin treated skin which gives a tough surface. This sandwich being then pressed and subjected to heat. A laminate has been developed which is suitable for both inside and outside use. It is used by an architect and a builder in interior and exterior design. A Laminate can be worked by all the methods commonly employed by a builder. A Laminate has some weathering properties.
There were many disadvantages in the development of decorative laminates before they could be put on the market Its chief advantage is that it needs no maintenance other than an occasional wipe down with a damp cloth. Another important property is that curved surfaces can be introduced and sharp corners eliminated in areas where hygiene is an essential consideration.
Aluminum. One of the oldest and best known metal is aluminum. It has some characteristics. First of all, it is a while silvery metal. Thanks to low weight and resistance to corrosion aluminum is very suitable for the bodies of vehicles and also for casting-gear-boxes, pistons, cylinder hears. Also it is one of the metals widely used in the industry. It is used for making cooking utensils, ladders, refrigerators, wrapping material. Aluminum foil is used for the heat insulation of houses. One of aluminum’s characteristics is that it does not rust in the air. It is used in painting. Aluminum paint protects ironwork from rust, obliterates dark paint and reflects light. Any engineer must remember that aluminum is soft. That is why it is only used with other metals to make alloys light but very strong. Some important aluminum alloys are magnolium and duralumin (95% aluminum +4% copper +1/2% manganese +1/2% magnesium). It can be tempered be hear treatment. This alloy is used to make aircraft, houses, furniture and motor pistons.
Copper.This metal is found in nature in the form of ores but sometimes it is found in pure state. So we know pure copper. Pure copper has some specific characteristics. They differ it from other metals. First of all it is reddish colour. Also it has corrosion resistant qualities. Copper is the the best conductor of electricity. It is surpassed only by silver for conductivity of electricity. Thanks to copper’s conductivity it is widely used for electrical wiring and cables, such as telephone and telegraph cables, making of electrical apparatus, parts of dunamos and electric motors. Copper with other metals is used in alloys. There are thee important copper alloys.
The first is brass. Brass, including 20% zinc and 80% copper. It is important to know about zinc. Its colour is yellow when hot and while when cold. Zincis a hard grey metal which acquires a protective coating of zinc oxide on its surface. It burns in oxygen and chlorine with a bluish flame. Zinc oxide is used in paints because it is non-poisonous and is not discolored by hydrogen sylphlike. It has a soothing effect upon the skin and is used in ointments and lotions. It is added to rubber for making racing motor treys. Zinc is used in the making of dry batteries and in the process of galvanizing. In this way, iron is dipped into molten zinc, which forms a protective layer on its surface, and so prevents rusting. Galvanized iron is used in sheets for roofing and also for buckets and dustbins. This alloy of zinc and copper is header and cheaper than copper itself. It can be pressed info a shape. It resists corrosion. So brass hinges are used in preference to steel if they are exposed to weather.
The second is bronze. Bronze is an alloy of copper and tin. Tin is a silvery metal which is not corroded by air. Tin plate is suitable for cans in which acid fruit and other food-stuffs are packed because tin is not attacked by week acids. For good containers, iron is coated with tin instead of zinc because tin is not subject to attack by acids in food. Bronze, including 20% tin and 80% copper is very though. Bronze is used for making ship propellers, parts of machinery subject to hard wear and for doors and windows.
And the third one is copra-nickel (75% copper + 25% nickel). Last one is used for the present “silver” coins.
For a very long time such a combination as supplies including metals lead, zinc with supplies is known. It was mentioned about zinc. It is high time to tell some words about lead. Lead is a grey malleable metal which melts at 327°C, which is low for a metal. Earlier it was used for roofing and for water piping because of its softness and resistance to corrosion. Today copper and iron have taken its place. Now lead is a very expensive metal. But lead is still used for roofing and for making waste pipes and sink traps because it is easily bent into shape, storage battery (accumulator) plates, cable sheaths, storage tanks for sulphuric acid, lead shot, solder, screens to stop harmful radiation from radioactive substances. Other lead alloy is a type of making such as lead, tin, bismuth, cadmium. Lead monoxide is used for making glass that it is brilliant and sparking.
It is known that the earth contains a large number of metals which are useful to man .One of the most important of these is iron. Modern industry needs considerable quantities of this metal, either in the form of iron or in the form of steel. A certain number of non-ferrous metals, including aluminium and zinc are also important, but even today the most part of our engineering products are of iron and steel. It is necessary to note that iron possesses magnetic properties, which have made the development of electrical power possible.
The iron ore, which we find in the earth, is not pure. It contains some impurities that must be removed by means of smelting. The process of smelting consists of heating the ore in a blast furnace from the bottom and provides the oxygen which is necessary for the reduction of the ore. The ore becomes molten and its oxides combine with carbon from the coke. The non-metallic constituents of the ore combine with the limestone and form a liquid slag. This slag floats on the top of the molten iron and passes out of the furnace through a tap. The metal which remains is pig-iron.
We can melt this down again in another furnace — a cupola — with more coke and limestone. This is cast-iron. Cast iron doesn’t have the strength of steel. It is brittle and may fracture under tension. But it possesses a number of properties which make it very useful in manufacture of machinery. In the molten state it is vеrуfluid, and therefore it is easy to cast it into complex shapes. Also it is easy to machine it.
Cast-iron contains small proportions of other substances. These non-metallic constituents of cast-iron contain carbon, silicon and sulphur, and the presence of these substances affects the behaviour of the metal. Iron, which contains a small quantity of carbon, for example, wrought-iron, behaves differently from the iron which contains a lot of carbon.
METHODS OF STEEL HEAT TREATMENT
It is possible to change the characteristics of steel in various ways. Steel which contains very little carbon will be milder than that which contains a higher percentage of carbon up to the limit about 1,5%. One can heat the steel above a certain critical temperature, and then allow it to cool at different rates.
At this critical temperature changes take place in the molecular structure of the atоm. In the process known as annealing, we heat the steel above the critical temperature and allow it to cool very slowly. The metal becomes softer than before, and its machining becomes easier.
One can make steel harder by rapid cooling. We heat it up beyond the critical temperature and drop it in water or some other liquid. Then we heat it again to the temperature below the critical one, and cool it slowly. This treatment is called tempering. It makes the steel less brittle. The properties of temperatured steel allow us to use it in the manufacture of tool which need a rather hard steel. High carbon steel is harder than the temperatured that, but it is much difficult to work. These heat treatments take place during various shaping operations.
BASIC ENGINEERING PROCESSES
A major advance in twentieth century manufacturing was the development of mass production techniques. Mass production refers to manufacturing processes in which an assembly line, usually a conveyer belt, moves the product to stations where each worker performs a limited number of operations until the product is assembled. In the automobile assembly plant such systems have reached a highly-developed form. A complex system of conveyer belts and chain drives moves car parts to workers who perform the thousands of necessary assembling tasks.
Mass production increases efficiency and productivity to a point beyond which the monotony of repeating an operation over and over slows down the workers. Many ways have been tried to increase productivity on assembly lines: some of them are as superficial as piping music into the plant or painting the industrial apparatus in bright colors; others entail giving workers more variety in their tasks and more responsibility for the product.
These human factors are important considerations for industrial engineers who must try the balance an efficient system of manufacturing with the complex needs of workers.
Another factor for the industrial engineer to consider is whether each manufacturing process can be automated in whole or in part. Automation is a word coined in the 1940s to describe processes by which machines do tasks previously performed by people. The word was new but the idea was not. We know of the advance in the development of steam engines that produced automatic valves. Long before that, during the Middle Ages, windmills had been made to turn by taking advantage of changes in the wind by means of devices that worked automatically.
Automation was first applied to industry in continuous-process manufacturing such as refining petroleum, making petrochemicals, and refining steel. A later development was computer-controlled automation of assembly line manufacturing, especially those in which quality control was an important factor.
Automation is the system of manufacture performing certain tasks, previously done by people, by machines only. The sequences of operations are controlled automatically. The most familiar example of a highly automated system is an assembly plant for automobiles or other complex products.
The term automation is also used to describe non-manufacturing systems in which automatic devices can operate independently of human control. Such devices as automatic pilots, automatic telephone equipment and automated control systems are used to perform various operations much faster and better than could be done by people.
Automated manufacturing had several steps in its development. Mechanization was the first step necessary in the development of automation. The simplification of work made it possible to design and build machines that resembled the motions of the worker. These specialized machines were motorized and they had better production efficiency.
Industrial robots, originally designed only to perform simple tasks in environments dangerous to human workers, are now widely used to transfer, manipulate, and position both light and heavy workpieces performing all the functions of a transfer machine.
In the 1920s the automobile industry for the first time used an integrated system of production. This method of production was adopted by most car manufacturers and became known as Detroit automation.
The feedback principle is used in all automatic-control mechanisms when machines have ability to correct themselves. The feedback principle has been used for centuries. An outstanding early example is the flyball governor, invented in 1788 by James Watt to control the speed of the steam engine. The common household thermostat is another example of a feedback device.
Using feedback devices, machines can start, stop, speed up, slow down, count, inspect, test, compare, and measure. These operations are commonly applied to a wide variety of production operations.
Computers have greatly facilitated the use of feedback in manufacturing processes. Computers gave rise to the development of numerically controlled machines. The motions of these machines are controlled by punched paper or magnetic tapes. In numerically controlled machining centres machine tools can perform several different machining operations.
More recently, the introduction of microprocessors and computers have made possible the development of computer-aided design and computer-aided manufacture (CAD and CAM) technologies. When using these systems a designer draws a part and indicates its dimensions with the help of a mouse, light pen, or other input device. After the drawing has been completed the computer auto.
Manufacturing systems today are designed to recycle many of their components. For example, in the automotive industry, excess steel and aluminum can become scrap stock for new metal, rubber tires can be chopped and mixed with asphalt for new roadways, and engine starters can be remanufactured and sold again. Recycling for newer materials, such as composites (combinations of materials designed with superior physical and mechanical properties), has yet to be developed, however.
Emission control will be a critical issue for future manufacturers. Smoke scrubbers must remove dangerous gases and particulates from industrial plant discharges, and manufacturing facilities that dump chemicals into rivers must develop methods of eliminating or reusing these waste products.
The economically advantageous automated factory has become the norm. Most automobile engines are manufactured using robotic tools and handling systems that deliver the engine to various machining sites. Computers with sophisticated inventory tracking programs make it possible for items to be assembled and delivered at the manufacturing facility only as they are needed. In demand-activated manufacturing, when an item is sold a computer schedules the manufacture of an item to replace the unit sent to the customer.
Engineers use computers to help them design new products efficiently. The Boeing 777 jet, for example, was developed in record time by having its entire design and manufacturing systems created on a computer database rather than using traditional blueprints.
MODERN COMPUTER TECHNOLOGIES
DVD disc is sometimes called «Digital Versatile Disc» or «Digital Video Disc». It is an optical storage media format that can be used for data storage, including movies with high video and sound quality. DVDs resemble compact discs as their physical dimensions are the same – 12cm in diameter but they are encoded in a different format and at a much higher density, using the Universal Disc Format (UDF) file system.
In the early 1990s two high density optical storage standards were being developed: one was the MultiMedia Compact Disc (MMCD), backed by Philips and Sony, and the other was the Super Density Disc (SD), supported by Toshiba, Time-Warner, Matsushita Electric, Hitachi, Mitsubishi Electric, Pioneer, Thomson, and JVC. Later IBM´s president, Lou Gerstner, acting as a matchmaker, led an effort to unite the two camps behind a single standard, anticipating a repeat of the costly format war between VHS and Betamax in the 1980s.
Philips and Sony abandoned their MMCD format and agreed upon Toshiba´s SD format with two modifications that are both related to the servo tracking technology.
The first DVD players and discs were available in November 1996 in Japan, March 1997 in the United States, 1998 in Europe and in 1999 in Australia. The first DVD movie appeared in 1996 the movie had the first test for 2.1 surround sound. In 1999 Independence Day was the first movie to introduce 5.1 surround sound.
By the spring of 1999 the price of a DVD player had dropped below the US $300. As a result Wal-Mart began to offer DVD players for sale in its stores.
As of 2006 DVD sales make up the bulk of gross sales and VHS is a slim minority. The price of a DVD player has dropped significantly. Many modern computers are sold with DVD-ROM drives stock.
All cultures have their own traditions and customs. That`s why it is important to know about them. Of cause, architecture has its own history. There are a lot of different kinds of architectural styles, describing some features of every country. For example, red brick buildings of old Petersburg factories, grey Ferro – concrete cases of industrial giants tell us about Soviet epoch. But, today they look old-fashioned. Besides external unattractiveness, these constructions of the last centuries have lacks. They are internal narrowness, conditions of communications in these buildings. In particular, because of these lacks it is impossible to organize a modern competitive manufacture. The majority of the companies do not prefer building of new constructions, using the most. Perspective materials and technologies, including an easy metallic construction (LMC).
Let`s tell some words about a basic fast construction for buildings. It is a metal skeleton. There metal vertical racks and horizontal crossbar with the help bolt connections gather in cross-section frames. The cross-section frames are a system of extensions or communications, giving to design settlement durability fastens. Then it is established roofing, wall runs, frames under windows, doors. Any engineer may say that a bearing skeleton is ready. Further it is possible to use any facing. It can be Ferro-concrete, bricklaying, special panels such as <<sandwich>>, any combinations of the specified designs. It is necessary to tell some words about panels such as <<sandwich>>. Every panel consist of two sheets of the zinced iron between which a special heater is placed due to the certain orientation of fibers.
It is very important for a future skilled engineer to remember about a distinctive feature such as <<fast>>. It is a high degree of a factory`s readiness to complete the building. In practice it is carried out as follows. All details, delivered to a building site, are made at a factory with their obligatory test characteristics of strong. On a building site all elements of a design are gathered with the help bolt connections. With the purpose, excepting possible problems during installation, all details are adjusted to each other on the factory-manufacturer control assembly of each design.
The scope of fast metallic construction is very wide. For example, metallic construction is not used at construction of buildings in which nuclear reactors will place, or bank storehouses. There wall`shes and roofing designs should possess raised isolation properties. It is not accepted to use them. Practically, fast metallic constructions are used at the construction of any industrial targets, warehouses, sports complexes. Recently fast construction designs are used in the field of trading constructions.
Every construction has its own advantages and disadvantages. Advantages of a fast metallic construction are obvious. A cost of a building from a metallic construction is 30-40 % less, than on construction of a similar building, using traditional materials. Naturally, the given statement is correct only under condition of the certain identity of quality of external and internal furnishing. For example, the building constructed from the cheapest brick without additional external furnishing, will be cheaper than a construction from a fast metallic construction with a façade trimmed with dark glass. The essential economy, while using a metallic construction, is reached to decrease in expenses of a zero cycle approximately on 50 %. Today a fast metallic construction is a leader among all building design, fast of all, because of its low price. On the other hand, it has the shortest terms of erection. The economy of time can become very significant and essentially important for any customer. Besides the price and terms of assembly, fast metallic constructions have more important advantage. The matter is that a metallic construction is not only quickly gathered, but also can be disassembled fast and without special financial expenses.
There are a lot of benefits from an open system like the Internet, but we are also exposed to hackers who break into computer systems just for fun, as well as to steal information or propagate viruses. So how do you go about making online transactions secure?
Security on the Web.
The question of security is crucial when sending confidential information such as credit card numbers. For example, consider the process of buying a book on the Web. You have to type your credit card number into an order form, which passes from computer to computer on its way to the online bookstore. If one of the intermediary computers is infiltrated by hackers, your data can be copied. It is difficult to say how often this happens, but it's technically possible.
Tb avoid risks, you should set all security alerts to high on your Web browser. Netscape Communicator and Internet Explorer display a lock when the Web page is secure and allow you to disable or delete 'cookies'.
If you use online bank services, make sure your bank uses digital certificates. A popular security standard is SET (secure electronic transactions).
Similarly as your e-mail message travels across the net, it is copied temporarily on many computers in between. This means it can be read by unscrupulous people who illegally enter computer systems.
The only way to protect a message is to put it in a sort of 'envelope', that is, to encode it with some form of encryption. A system designed to send e-mail privately is Pretty Good Privacy, a freeware program written by Phil Zimmerman.
Private networks connected to the Internet can be attacked by intruders who attempt to take valuable information such as Social Security numbers, bank accounts or research and business reports.
To protect crucial data, companies hire security consultants who analyze the risks and provide security solutions. The most common methods of protection are passwords for access control, encryption and decryption systems, and firewalls.
Viruses can enter a PC through files from disks, the Internet or bulletin board systems. If you want to protect your system, don't open e-mail attachments from strangers and take care when downloading files from the Web. (Plain text e-mail alone can't pass a virus.)
Remember also to update your anti-virus software as often as possible, since new viruses are being created all the time.