Unit 1, Lesson 1.3, Exercise E ≤1.5
Introduction 1 Today I’m going to talk about the different branches of mechanical engineering. There are four main branches. Firstly, there is the development of machines for the production of goods like cars and food. Secondly, there is the development of machines for the production of power – electricity, nuclear. Thirdly, there is the development of military weapons, such as guns, tanks and planes. Finally, there is the branch concerned with environmental control – for example, heating or cooling your environment.
Introduction 2
In this lecture, I’m going to look at metal fatigue. Fatigue means tiredness in general English. Metals can’t get tired in the real sense of the word. But, under certain circumstances, they can become weakened. I'm going to look at the causes of metal fatigue, and the effects.
Introduction 3
OK. Are we all ready? Right, I'll begin. For centuries, mechanical engineers have tried to control their environment. In this lecture, we’re going to look at one way in which machinery can change a local environment – air conditioning. First, I’m going to talk briefly about the history of air conditioning. Then I’ll describe how an air conditioning system works.
Introduction 4
This week I’m going to talk about how it all began. Who were the first true mechanical engineers? When did mechanical engineering begin? We could say it started with the founding of the Institution of Mechanical Engineers in Birmingham, England, in 1847. But really this branch of engineering began some time before, with the Industrial Revolution.
Introduction 5
In this week’s lecture, I’m going to consider the functions of a mechanical engineer. There are four main functions which are common to all branches of the profession. Firstly, mechanical engineers must understand and deal with basic principles of mechanical science. Secondly, mechanical engineers are involved in the RDD sequence – that is, research, design and development. Thirdly, there is the question of production – production of goods or production of power. Fourthly, and finally, we have management functions, which include consultancy.
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Unit 1, Lesson 1.4, Exercise E ≤1.6
Lecture 1 Let’s look first at the production of goods. Advances in mechanical engineering have led to faster and better machines. This means that machines can produce more things of a higher quality than before. Perhaps the best example of mechanical engineering in the production of goods is the automobile assembly line. At one time, hundreds of people were required to work on the line. Now, there are only a few supervisors controlling machines which do the cutting, welding, assembly and painting. In many cases, the supervisors do not work directly with the machines at all. Instead, they monitor computers which control all the operations. And what about the quality of manufactured goods? Well, one story will illustrate the importance of accuracy in machining. Charles Babbage invented the first computer over 150 years ago, but the machines of his time were not accurate enough to build the machine. With better machining, perhaps the Information Age could have started a hundred years earlier.
Now, what about the production of power? Well, man has used water and the wind for hundreds of years to power mills. But the invention of the steam engine marked the start of the Industrial Revolution. The steam engine was an external combustion engine. In other words, heat was applied externally or outside the main machinery. The invention of the internal combustion engine was the next revolution in the production of power. Then, in the 20th century, we saw the growth of nuclear energy. Interestingly, we are now going back to old sources of power to find renewable energy – wind, water and the sun. Mechanical engineers must make machines to use these renewable sources efficiently.
The third branch of mechanical engineering is the development of military weapons. Many advances in peaceful applications, such as the jet engine, appeared initially for military purposes. So although we may not be happy about it, war has proved a powerful motivation for mechanical engineers.
Finally, let’s consider environmental control. Perhaps you think that concern for the environment is a feature of modern life. But in fact, mechanical engineers have always been involved in trying to control or improve the environment. Centuries ago, they were involved in drainage of land in wet countries and irrigation of land in dry countries. Later, they were involved in
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