The teaching on the courses is partly by lectures but much of time is spent in smaller group work, in seminars and tutorials.
In addition to the higher degrees of MPhil (Master of Philosophy), PhD (Doctor of Philosophy) and MSc(Master of Science) the courses lead to a wide range of first degrees and diplomas.
A high proportion of students live away from home; over 1,300 being accommodated in Polytechnic residential units. The main campus has hostel places for 600 students.
The Polytechnic Students’ Union represents students on various Polytechnic Committees. It operates a number of national services for local students (such as accommodation, medical, financial, legal and other problems).The Students’ Union organizes and supports a wide range of social, recreational and cultural activities. A large number of clubs and societies are organized by it, which arrange entertainment. There are film, music, drama, poetry, blues and folk societies; rugby, judo, crosscountry running, badminton and horse riding clubs. In addition, there are academic, political and other societies at the Polytechnic.
Higher Education in the United States
There are more than two thousand institutions of higher education in the United States with the number of students ranging from fewer than a hundred to 40,000.
Young people who want to enter higher education must meet some requirements. They must have attended a high school for four years. No student is admitted to a college or university without having completed a four-year course in high school. This means that a student who wants to study at the university or college must begin by doing good work in high school. If his grades in high school are satisfactory, he is admitted to a university or college, where he may take a Bachelor’s degree after a four-year course of study. About fifty three per cent of pupils who complete their high school course go on to a college or university.
The first two years in an American college or university differ somewhat from a similar period in a European one. These years in American college are a continuation of secondary education. During this time certain courses in English, social sciences, natural sciences and so on must be completed before a student may begin an intensive study of this special field.
Nearly all of colleges and universities in the United States are coeducational. This means both men and women attend the same university. It is common for students to leave home to study, and only about 15% of all university students live at home while they study. Students may live either on the university campus in one of the dormitories or in private homes in the city in which the University is located.
University life provides a wide variety of recreational activities. Although a great deal of time must necessarily be devoted to study, students find time for recreation. There are football, basketball, and baseball games, teas and dances, concerts, debates, club programs and plays, to mention only a few of the many activities. Most recreational activities are not expensive for the student.
US Academia: Some Explanations
The American academic year usually runs from some time in September to the end of May. Most, although not all, scools run on a semester system. Achievement is measured by grades which are given on papers and tests during the course of the semester and a final examination at the end of the semester. The final grade is based on all of the work done for the course. At the university level, grades are usually given in the form of letters that correspond to numbers 1-4, with 4 indicating excellence. A grade point average (GPA) is determined at the end of a term to show overall achievement.
The degree programs contain several major courses and a certain number of credit hours is given for every course. A student must take a predetermined number of credit hours in order to graduate. One can drop or add a course in the beginning of the term but not in the middle of the semester. Withdrawing from a course midsemester will be noted on grade records. Students are ecouraged to discuss any academic problems or questions they may have with their academic adviser.
In the classroom, Americans are encouraged to ask questions and to voice their opinions, even if they differ from those of the professor. Also, professors expect papers to be typed and not handwritten.
American and European Systems Compared
Education in America is largely the business of the individual State, not of the Federal Government. Each of fifty states has its own system of education. There is no Minister of Education such as exists in many other countries, no national system of education. In addition to public schools, academies, colleges and universities, there is a great number of private institutions of education. The Federal Government of the United States doesn’t interfere in any way with public education within the States.
Americans tend to study a larger number of subjects than Europeans, in schools, and particularly at the university. Seven subjects are required for a first degree (Bachelor’s degree) in many colleges. In the USA wide, and sometimes superficial, knowledge is often valued more than specialization.
The aim of American education is to create a good citizen, rather than a scholar. That is why great emphasis is placed on social duties and obligations, on communicating with other people, and obtaining varied information, which will be of practical use in life.
The Engineering Profession
Engineering is one of the most ancient occupations in history. Without the skills included in the broad field of engineering, our present-day civilization never could have evolved. The first toolmakers who chipped arrows and spears from rock were the forerunners of modern mechanical engineers. The craftsmen who discovered metals in the earth and found ways to refine and use them were the ancestors of mining and metallurgical engineers. And the skilled technicians who devised irrigation systems and erected the marvellous buildings of the ancient world were the civil engineers of their time.
Engineering is often defined as making practical application of theoretical sciences such as physics and mathematics. Many of the early branches of engineering were based not on science but on empirical information that depended on observation and experience.
The great engineering works of ancient times were constructed and operated largely by means of slave labor. During the Middle Ages people began to seek devices and methods of work that were more efficient than human. Wind, water, and animals were used to provide energy for some of these new devices. This led to the Industrial Revolution which began in the eighteenth century. First steam engines and then other kinds of machines took over more of the work that had previously been done by human beings or by animals. James Watt, one of the key figures in the concept of horsepower to make his customers understand the amount of work his machines could perform.
Since the nineteenth century both scientific research and practical application of its results have escalated. The mechanical engineer now has the mathematical ability to calculate the mechanical advantage that results from the complex interaction of many different mechanisms. He or she also has new and stronger materials to work with and enormous new sources of power. The Industrial Revolution began by putting water and steam to work; since then machines using electricity, gasoline, and other energy sources have become so widespread that they now do a very large proportion of the work of the world.
The Role of Science in Manufacture
Future improvements in productivity are largely dependent on the application of science to manufacturing. This depends in turn on the availability of large numbers of scientifically trained engineers. The higher schools can serve the needs of industry in two ways: by performing basic research and by training well-qualified engineers in the manufacturing field.
There is a growing need for engineers who are familiar with the fundamental problems in metal processing and manufacturing. In the near future many of the engineers will be recent university graduates. A few will come through courses of study in industry. Others, having a basic engineering knowledge, will continue additional studies at colleges to prepare themselves for work in industry. Therefore, an engineer does not finish his education when he receives his diploma, particularly in the fields of interest to tool engineers who are to study new developments constantly.
There are numerous ways in which industry and education can cooperate on problems of common interest. Scientists and research are engaged in work that is intended to provide a scientific approach to many purely industrial problems. These scientists and engineers can make a real contribution to engineering education or academic research. They can, for example, teach advanced engineering courses and they can actively participate in basic and applied research.
Similarly, large and complicated projects of new technologies could well be handled by institute researchers working on practical applications. This would often provide the most efficient approach to the solution of processing problems.
Four Industrial Revolutions
The history of mechanical engineering goes back to the time when the man first tried to make machines. We can call the earlier rollers, levers and pulleys, for example, the work of mechanical engineering.
Mechanical engineering, as we understand it today, starts from the first Industrial Revolution.
People have labelled as «revolutions» three episodes in the industrial history of the world and now we are entering the fourth.
The first industrial revolution took place in England between 1760 and 1840. Metal became the main material of the engineer instead of wood, and steam gave man great reserves of power. This power could drive not only railway engines and ships but also the machines which built them.
In the second revolution, from 1880 to 1920, electricity was the technical driving force. It provided power for factories that was easier and cheaper to control than steam. It was marked also by the growing importance of science-based industries such as chemicals and electrical goods, and the use of scientifically-designed production methods such as semi-automatic assembly lines.
The third industrial revolution coincided with the advent of automation-in its inflexible form. In this revolution, the main features were advances in the control of manufacturing processes so that things could be made more cheaply, with greater precision and (often) with fewer people. And this change, which occurred around the middle of this century, also featured a new machine that was to greatly influence the world, the electronic computer.
What is the fourth industrial revolution?
The fourth industrial revolution will be characrerized by automated machines that are versatile and programmable and can make different things according to different sets of computer instructions. It will be characterized by flexible, automated machinery, the most interesting example of which are robots.
The Wankel Engine
The Wankel engine is a form of heat engine that has a rotary piston.In other words,instead of going up and down the Wankel piston rotates in the cylinder.Boht cylinder and piston are quite different in shape from those of conventional engines. The Wankel piston is tringular with curved sides, the cylinder is roughly oval in shape. The piston has an inner dore which is liked through an eccentrik gear to the output shaft. The other end of the dore is toothed and engaged with a stationary gear fixed to the cylinder end. Their arrangement ensures that the piston follows an elliptical path round the cylinder so that the apexes of the piston, which carry gastight seals, are always in contact with the inside surface of the cylinder
The piston thus forms thrree crescent-shaped spaces between itself and the cylinder wall, which vary in size as the piston rotates. Fuel enters the cylinder through the inlet port when one of these spaces is increasing in size. The fuel trapped in this section is then compressed by the turning piston and ignited by the sparking plug. The expanding gases subject the piston to a twisting moment which makes the piston revolve further until the exhaust gases escape through the exhaust port. A fresh charge is then induced into the cylinder. Meanwhile the same process is being repeated in the other two spaces between the piston and the cylinder.
The Wankel engine has many advantages over the reciprocating piston engine. Fewer moving parts are necessary because it produces a rotary movement using a connecting rod and a crankshaft. Because of this rotary movement it has vibration. In addition it has no valves, it is smaller and lighter than conventional engines of the same power, and it runs economically on diesel and several other fuels.
Engine
An engine produces power by burning air and fuel. The fuel is stored in a fuel. The fuel tank is connected to a fuel pipe. The fuel pipe carries the fuel to a fuel pump. The fuel pump is connected to the carburettor. The fuel pump pumps the fuel into the carburettor. In the carburettor the fuel is mixed with air. The fuel and air are drawn into the engine cylinder by the piston. Then the fuel and air are compressed by the piston and ignited by the spark plug. They burn and expand very quickly and push the piston down. Then the power is produced. The burned fuel and air are expelled from the cylinder by the piston.
The flow of gases into and out of the cylinder is controlled by two valves. There is an inet valve allowing fresh fuel mixture into the cylinder and an exhaust valve which which allows the burnt gases to escape.
There are two clasic engine operating cycles:
the four-stroke cycle;
the two-stroke cycle.
The complete four-stroke cycle comprises:
the induction stroke (the piston moves downwards):
the compression stroke(the piston moves upwards);
the power stroke (the piston moves downwards);
the exhaust stroke (the pistone moves upwards).
Machines and Work
Defined in the simplest terms a machine is a device that uses force to accomplish something. More technically, it is a device that transmits and changes force or motion into work. This definition implies that a machine must have moving parts. A machine can be very simple, like a block and tackle to raise a heavy weight, or very complex, like a railroad locomotive or the mechanical systems used for industrial processes.
A machine receives input from an energy source and transforms it into output in the form of mechanical or electrical energy. Machines whose input is a natural source of energy are called prime movers. Natural sources of energy include wind, water, steam, and petroleum. Windmills and waterwheels are prime movers; so are the great turbines driven dy water or steam that turn the generators that produce electricity; and so are internal combustion engines that use petroleum products as fuel. Electric motors are not prime movers, since an alternating current of electricity which supplies most electrical energy does not exist in nature.
Terms like work, force, and power are frequently used in mechanical engineering, so it is necessary to define them precisely. Force is an effort that results in motion or physical change. If you use your muscles to lift a box you are exerting force on that box. The water which strikes the blades of a turbine is exerting force on those blades, thereby setting them in motion.
In a technical sense work is the combination of the force and the distance through which it is exerted.
To produce work, a force must act through a distance. If you stand and hold a twenty-pound weight for any length of time, you may get very tired, but you are not doing work in an engineering sense because the force you exerted to hold up the weight was not acting through a distance. However, if you raised the weight, you would be doing work.
Power is another term used in special technical sense in speking of machines. It is the rate at which work is performed.
In the English-speaking countries, the rate of doing work is usually given in terms of horsepower, often abbreviated hp. You will remember that expression resulted from the desire of inventor James Watt to describe the work his steam engines performed in terms that his customers could easily understand.After much experimentation,he settled on rate of 33,000 footpounds per minute as one horsepower.
In the metrick system power in terms of watts and kilowatts.The kilowatt,a more widely used term, equals a thousand watts or approximately 1 1/3 horsepower in the English system.
Components of the Automobile
Automobiles are trackless, self-propelled vehicles for land transportation of people or goods, or for moving materials. There are three main types of automobiles. They are passenger cars, buses and lorries (trucks).The automobile consists of the following components: a)the engine; b)the framework: c)the mechanism that transmits the power-engine to the wheels; d)the body.
Passenger cars are, as a rule, propelled by an internal combustion engine. They are distinguished by the horse-power of the engine, the number of cylinders on the engine and the type of the body, the type of tpansmission, wheeelbase, weight and overall length.