Вариант № 2

(Автоматизация)

What can robots do?

The word "robot" was first used by Czech playwright Karel Capek who in 1920 wrote a drama about machines that could move like human beings - and do their work. Today this idea has become a reality. Industrial robots now being manufactured perform certain tasks even better than a human being. We are thus at the threshold of the era of robots - what might be called a "robolution".

An industrial robot is a unit which has movement functions with a high degree of freedom similar to human arms and hands and is able to move autonomously on the basis of sense and perceptions.

There are six categories of robots: (1) the manual manipulator, remotely controlled by a person which carries out hand-and-arm functions to hold and move objects; (2) the fixed-sequence robot, which performs a series of operations in a preset order, always in the same series of locations in space; (3) the variable-sequence robot, which operates in the same manner as a fixed-sequence robot but can easily be reprogrammed for a different sequence of operations; (4) the playback robot, which repeats a sequence of movements and operations that are first "taught" by manual movement of a manipulator and stored in the robot's memory unit; (5) the numerically-controlled robot, which moves from one position to another according to numerical instructions in such forms as punched paper tapes or cards; and (6) the intelligent robot, an advanced type that can decide its course of action on the basis of its sensing devices and analytical capability.

Today robots playa major role in welding, press-forming, coating and other operations, particularly in the automotive industry.

(Промышленная электроника)

Software

A computer to complete a job requires more than just the actual equipment or hardware we see and touch. It requires Software – programs for directing the operation of a computer or electronic data.

Software is the final computer system component. These computer programs instruct the hardware how to conduct processing. The computer is merely a general purpose machine which requires specific software to perform a given task. Computers can input, calculate, compare, and output data as information. Software determines the order in which these operations are performed.

Programs usually fall in one of two categories: system software and applications software.

System software controls standard internal computer activities. An operating system, for example, is a collection of system programs that aid in the operation of a computer regardless of the application software being used. When a computer is first turned on, one of the system programmes is booted or loaded into the computers memory. This software contains information about memory capacity, the model of the processor, the disk drives to be used, and more. Once the system software is loaded, the applications software can be brought in.

(Электроснабжение)

Semi-conductors

The term "Semi-conductors" means "half-conductor", that is, a material whose conductivity ranges between that of conductors and non-conductors of insulators.

They include a great variety of elements (selicon, germanium, selenium, phosphorus and others), many chemical compounds (oxides, sulphides) as well as numerous ores and minerals.

While the conductivity of metals is very little influenced by temperature, the conductivity of semi-conductors increases sharply with heating and falls with cooling. This dependence has opened great prospects for employing semi-conductors in measuring techniques. Light as well as heat increases the conductivity of semi-conducting materials, this principle being used in creating photo resistances. It is also widely applied for switching on engines, for counting parts on a conveyer belt, as well as for various systems of emergency signals and for reproducing sound in cinematography. Besides reacting to light, semi-conductors react to all kinds of radiations and are therefore employed in designing electronic counters.

(Химия)

Charge-transfer and thermochromic phenomena in solid polyelectrolytes

An important area of contemporary polymer science is the study of macromolecules exhibiting a highly specific physical response to changes in their environment. The most complex examples of such polymers are found in biological systems but fundamental studies on this subject require the use of simpler macromolecules. An example of macromolecules with inherent chromatic properties is the poly(diacetylenes). The wavelength of visible light absorption in these polymers depends on degree of polymerization, molecular structure, solvent, temperature, and the nature of the solid phase. Other examples are the poly(bisthiophenes) which exhibit electrochromic behavior and the group of ionenes known as poly(xylyl viologens) (PXV).

The bipyridinium moiety present in the backbone of PXV's is known to exhibit chromatic activity as a result of charge-transfer complexation. The sensitivity of charge-transfer energy levels in these polymers to structural features and molecular environment is one factor that remains unclear at the present time. Structural features that may be important include repeating-unit chemistry as well as macromolecular and Coulombic structure. Coulombic structure would include the distribution of condensed vs. loosely bound counterions in the solid polyelectrolyte. The thermochromic behavior of these solid bipyridinium polyelectrolytes has been studied as well. The investigation included macroion synthesis followed by experiments with techniques such as visible reflectance spectroscopy, thermogravimetric analysis, X-ray diffraction and infrared spectroscopy.

(Машиностроение)

Machine-tool

The machine-tool is the principal manufacturing equipment in a machine shop. It is essential in the manufacture of every product from a giant turbine to minute jewels for aircraft instruments. One of the simplest tools is the ordinary drilling machine.

It consists of a spindle which imparts rotary motion to the drilling tool, mechanism for feeding the tool into the work, a table on which the work rests, and a frame.

The drilling machines or drill presses are grouped into the following four classes: sensitive, upright, radial and multi-spindle machines.

A milling machine is a machine-tool that removes metal as the work is fed against a rotating cutter.

The lathe is a machine-tool which can perform a wide variety of operations. It is primarily used for turning and boring operations. In addition, the lathe can be used for drilling, reaming, tapping and, by employing suitable adapters, operations of milling and grinding may be carried out without difficulty.

The lathe is the oldest machine-tool, but it is still widely used.

There are many types of lathes that differ in their size, design, method of drive, arrangement of gears and purpose.

According to the character of work performed, the design and construction lathes are divided into the following types: bench lathes, chucking lathes and automatic lathes. There are also screw machines, boring mills, crankshaft lathes, wheel lathes, etc.

(Гражданское строительство)

Reinforced concrete

Reinforced concrete is a combination of two of the strongest structural materials, concrete and steel.

This term is applied to a construction in which steel bars or heavy steel mesh are properly embeded in concrete. The steel is put in position and concrete is poured around and over it then tamped in place so that the steel is completely embeded. When the concrete hardens and sets, the resulting material gains great strength. This new structural concrete came into practical application at the turn of the 19th century. The first results of the tests of the reinforced concrete beams were published in 1887. Since that time the development of reinforced concrete work has made great progress. And the reasons of this progress are quite evident. Concrete has poor elastic and tensional properties, but it is rigid, strong in compression, durable under and above ground and in the presence or absence of air and water, it increases its strength with age, it is fireproof.

Steel has great tensional, compressive and elastic properties, but it is not durable being exposed to moisture, it loses its strength with age, or being subjected to high temperature. So, what is the effect of the addition of steel reinforcement to concrete?

Steel does not undergo shrinkage or drying but concrete does and therefore the steel acts as a restraining medium in a reinforced concrete member. Shrinkage causes tensile stresses in the concrete which are balanced by compressive stresses in the steel.

(Экология)

Problems of the contemporary environment

The environmental question is one of the key issues of our era and as such is directly and indirectly linked with other important international problems, namely overgrowth of population, hunger, poverty, peace and disarmament, the need for a harmonious economic and social development. It has been repeatedly stated that the protection of our environment is a matter of survival of mankind on Earth as such it can only be tackled as an international – global issue. Furthermore, it is clear that in order to effectively protect the environment more and better focused research is needed as well as better and more efficient management of the environment and all natural resources.

Environmental degradation of large areas of our globe affects wide groups of population and is clearly international. Borders cannot impede air pollution, river or marine pollution, destruction of forests, desertification or soil erosion. National borders are often unable to hinder the expansion of environmental problems of a different nature such as the case the use of well-known dangerous substances, the transport – and in some cases uncontrolled disposal – of toxic or radioactive products, health problems directly connected with water use or food supply, etc. It is thus evident that environmental policy becomes more complex at national and international levels.

(Автомобилестроение)

Principle of operation of the four-stroke petrol engine

The internal combustion engine is called so because fuel is burned directly inside the engine itself. Most automobile engines work on a 4-stroke cycle. A cycle is one complete sequence of 4 strokes of the piston in the cylinder. The operating cycle of the four-stroke petrol engine includes: inlet stroke (intake valve opens), compression stroke (both valves closed), power stroke (both valves closed), exhaust stroke (exhaust vale is opened).

To describe the complete cycle let’s assume that the piston is at the top of the stroke and the inlet and the exhaust valves are closed. When the piston moves down the inlet valve opens to intake a charge of fuel into the cylinder. This is called the inlet stroke. On reaching the lowest position the piston begins to move upward into the closed upper part on the cylinder, the inlet valve is closed and the mixture is compressed by the rising piston. This is called the compression stoke. As the piston again reaches the top dead center the spark plugs ignite the mixture, both valves being closed during its combustion. As a result of burning mixtures the gases expand and great pressure makes the piston move back down the cylinder.

(Экономика)

Planned economics

Planned economies are sometimes called "command economies" because the state commands the use of resources (such as labour and factories) that are used to produce goods and services as it owns factories, land and natural resources. Planned economies are economies with a large amount of central planning and direction, when the government takes all the decisions, the government decides production and consumption. Planning of this kind is obviously very difficult, very complicated to do, and the result is that there is no society, which is completely a command economy. The actual system employed varies from state to state, but command or planned economies have a number of common features.

Firstly, the state decides precisely what the nation is to produce. It usually plans five years ahead. It is the intention of the planners that there should be enough goods and services for all.

Secondly, industries are asked to comply with these plans and each industry and factory is set a production target to meet. If each factory and farm meets its target, then the state will meet its targets as set out in the five-year plans. You could think of the factory and farm targets to be objectives which if met, allow the nation's overall aim to be reached.