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LUBRICANTS Lubricants can be liquids, solids, or even gases, and they are most often oils or greases. Liquid lubricants often provide many functions in addition to controlling friction and wear, such as scavenging heat, dirt and wear debris; preventing rust and corrosion; transferring force; and acting as a sealing medium. Engineers are called upon to select and evaluate lubricants, to follow their performance in service, and to use them to best advantage in the design of equipment. Lubri
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  LUBRICANTS   Lubricants can be liquids, solids, or even gases, and they are most often oils or greases. Liquid lubricants often  provide many functions in addition to controlling friction and wear, such as scavenging heat, dirt and wear debris;  preventing rust and corrosion; transferring force; and acting as a sealing medium. Engineers are called upon to select and evaluate lubricants, to follow their performance in service, and to use them to  best advantage in the design of equipment. Lubricant manufacturers and distributors may have hundreds of lubricants in their product line, each described separately in the product literature as to intended applications, properties, and  benefits, as well as performance in the selected standard tests. Lubricants are selected according to the needs of the  particular application. Careful lubricant selection helps obtain improved performance, lower operating cost, and longer service life, for both the lubricant and the equipment involved. Industry´s demands for efficient, competitive equipment and operations, which meet the latest environmental regulations, create continued demand for new and improved lubricants. Equipment manufacturers and suppliers specify lubricants that suit their particular equipment and its intended operating condition, and their recommendations should be followed. Liquid Lubricants A liquid lubricant consists of (1)  a mixture of selected base oils and additives, (2)  blended to a specific viscosity, with (3)  the blend designed to meet the performance needs of a particular type of service. A lubricant may contain several  base oils of different viscosities and types, blended to meet viscosity requirements, or to minimize cost. WHY BOTHER?  We are so used to hearing human voices from robots and computers in science fiction that the desirability of human-machine speech interaction is often taken for granted. However, this field of research has not been without its critic. The arguments have been based on several theoretical and commercial considerations. - The research (into speech recognition, in particular) is necessary to social needs, and the money would be better spent elsewhere. - Speech interaction may be more expensive in running costs than using written or coded text. It is unclear and the whether these costs are outweighed by the advantages. - The commercial demand for quick results has led to some poor-quality research and development - The ability to produce hardware is now far ahead of the relevant theoretical research fields, especially in speech  perception and acoustics. - Speech input to machines will be unreliable for the foreseeable future because of interference from other speech in the environment. - Routine speech input to machines leaves no permanent record, whereas written or coded output does. The concern to make machines sound human is unnecessary. Sometimes mechanical voices are more easily understood, especially in noisy work conditions. And friendly voice systems may persuade non-expert users that machines are capable of more than they really are. Many people do not like talking to machines because this suggest they have intelligence (a currently controversial issue, in its own right).  THE CASE FOR WIND POWER   For human development to continue, we will ultimately need to find sources of renewable or virtually inexhaustible energy. It's difficult to imagine this, but even if we find several hundred or even thousand years of coal and natural gas supplies, what will humans do for the next 250,000 years or so after they are depleted? Even the most apparently inexhaustible sources like fusion involve the generation of large amounts of waste heat -- enough to place damaging stress on even a robust ecosystem like Earth's, at least for the organisms that depend upon stability of the system to survive. We are engaged in a sort of world-wide biological experiment, with our descendents as the subjects. Our present habits of energy use are shaping an entirely different earth than the one with which we are familiar. When these changes begin to be expressed, there will be no one to preserve the familiar and there's no guarantee that things will turn out the best for our particular species. Some have looked ahead and seen this. But they usually don't get much support from societies that are too busy trying to make do and that are rushing backwards into the future -- in other words, every society on earth. One of the areas that suffers because of this backward thinking is the development of renewable energy sources -- and the topic of this section: Wind Energy Conversion. PREFERRED NUMBERS  Many manufactured articles are made in several sizes which may be designated by some dimension, speed, capacity, or other feature. Each such series of products may be paralleled by a series of numbers. It is generally agreed that such number series should be  geometric progressions;  i.e., each term should be a fixed  percentage larger than the preceding. A geometric series provides small steps for small numbers, large steps for large numbers, and this best meets most requirements. The small steps in the diameter of the numbered twist drills would  be absurd in drills of 1 in diameter and larger. In the case of sized objects that are used principally as raw material, .e.g., steel rod, an arithmetic progression may be  preferred because it tends to reduce the cost of machining. It is desirable to be able to buy raw material a fixed amount (rather than a fixed percentage) larger than the finished article. Preferred numbers is the name given to various series proposed to general use. These are either geometric  progressions or approximation thereto. A geometric series is defined by one term and the ratio of each term to the  preceding one. On the choice of these elements for a preferred number series, there is as yet no general agreement. The same value would hardly be satisfactory for all cases. The idea of preferred numbers is to provide a master series from which terms can be chosen to suit any needs. A fantasy spaceflight  Computers are about to take people to places they have never been able to visit before, including the surface of other  planets. Such a trip will be an illusion, but one that comes closer to real life than anything on stage or screen. Artificial worlds are being built up in a computer memory so that people can walk through at will, look around, and even touch objects. The system is called virtual reality, so called from the mathematical concept of an image that has the virtues of a real object without substance. Virtual reality systems are being developed throughout the world for a range of uses including enabling people to walk “inside” nuclear power stations, while controlling a robot that actually goes into an area in which no human could live, and conducting architects through a computer-generated building before it is constructed. British scientists have a world lead in virtual reality, despite the fortunes being poured into research by Japanese and American companies, which see it as a technology for the next century. In Britain, Robert Stone, of the National Advanced Robotics Research centre at Manchester University, is developing systems that could put men on Mars without shooting them into space.
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