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Electricity and Electronics
It is very difficult to separate the meaning of the two words “electricity” and “electronics”. The field of electricity is usually thought of as the electricity that is used in magnets, generators, motors, lights and heaters.
The field of electronics is usually thought of as electricity that is used in radio, television, and other equipment where electron tubes and transistors are needed. Basically electronics is not so much a new subject as a new way of looking at electricity. All electrical effects are really electronic because all electric currents result from the movements of electrons, and all electric charges are due to the accumulation of electrons.
Electronics is the science of practice of using electricity in devices similar to radio tubes so as to get results which are not possible with ordinary electrical equipment.
Although electronics has received greater attention in recent years, we have been using electronic equipment for half of a century. Radio, television, sound pictures, fluorescent lighting and long-distance telephone calls owe their existence to electronics. As most of these familiar equipments serve to carry or give information one may say that communication has been the major purpose of electronics.
Electronics is closely connected with a series of discoveries and inventions which have revolutionized the life of man in the twentieth century. In 1883 Thomas A. Edison discovered current conduction through gas in an incandescent lamp. This phenomenon known as the Edison effect, marked the birth of electronic science. The Edison effect was followed by the discoveries of electromagnetic waves, X‑rays, wireless communication and at last by the invention of the two-electrode detector or the “valve”. These basic discoveries and a lot of others have produced what is known as electronics.
Nothing can be done in a modern research laboratory without the aid of electricity and electronics. The word laboratory is used to denote any room or building devoted to experimental investigation in techniques and sciences for the purpose of advancing the man’s knowledge of special applications of natural laws. The word laboratory is also used to denote the work-room of a chemist or a testing-room of an industry. Nearly all the measuring devices used in industry and research are electrically operated. Electronics has found broad application in industry as a means of automation, control and inspection, and as a direct means of fulfilling such operations as melting, cutting of superhard materials and welding.
Among the greatest laboratories of the world may be noted the laboratory of the Royal Institution established in 1800 in Britain and devoted to the applied sciences. The laboratory soon became the seat of great activity in research in pure science conducted by such scientists as M. Faraday and J. Tyndall. The first physical laboratories founded for students appeared in 1846.
Nowadays laboratories are introduced into educational institutions to teach scientific and technical knowledge by means of experiments. Some laboratories have departments devoted to research in pure sciences and to the study of the application of study to industrial purposes.
Polymers in Use
In the field of organic chemistry it may be said that we are living in a “plastics age”. Many articles formerly constructed of metal, wood, rubber or leather have been replaced by plastics.
The use of plastics in home construction, automobiles, boats, airplanes and consumer goods has increased tremendously in the past few years. The superior properties of many plastics have resulted in the increased application of plastics in the electrical, radio, television and chemical industries. Plastics, synthetic rubbers, man-made fibres and films belong to a class of compounds called polymers. This means the molecules of these materials are very big, consisting of a huge number of atoms and with molecular weights that are enormous compared to those of ordinary materials.
Today there exists a great number of plastics materials and this number is being increased as new polymers are discovered. Polymers have made a significant contribution to some of the newer technologies. For example, the development of electronics depended considerably upon polymers for their excellent electrical insulating properties. The computer is another symbol of our age and computers are now being used to control the chemical processes that produce the polymers. The polymers, in turn, are being employed in the electrical circuits that constitute the heart of these machines.
Polymers have also played their part in the modern system of telecommunication and our ability to lift a telephone receiver in Kyiv and speak to somebody in New York is due to the use of special plastics in the submarine cables.
A great deal of researches had been carried out before and special grades of polymeric materials were obtained for space technology. Now they are in wide use in space vehicles because of their combination of light weight with the ability of performing certain functions. One of their uses is as protective coatings to protect them from burning as they re-enter the earth’s atmosphere. The problem arises because at the very high speeds of re-entry great heat is generated by air friction. No solid material can withstand these temperatures, sometimes of several thousand degrees Centigrade.
Land vehicles have also changed due to the use of polymers. Vehicles are nearly all painted and therefore have, at least, a surface coating of these materials. Car bodies made of polymeric materials offer not only considerable saving in weight but also good ease in repairing.
Building is another activity which makes extensive use of polymers. The latter have brought a new look to floors, walls, ceilings and furniture. In the filed of domestic appliances polymers are finding increasing opportunity especially through man-made fibres. Today synthetic fibres made from various polymers are being used in products varying from ropes and to fine textiles.
Radioactivity is dangerous. It may cause skin burns and it may destroy good tissues, as it destroys the diseased ones. It may cause illness that could be passed to our children and grandchildren. In cases of severe exposure it may even cause death.
In the early days of radioactivity scientists were not aware of those dangers. Marie Curie observed that although the radioactivity of uranium compounds, taken from pure chemicals, was proportional to the uranium content, the ores from which they were extracted showed much more radioactivity than could be accounted for by the uranium content alone. She then performed chemical analyses of the ores and measured the radioactivity of the isolated fractions. This method led to the discovery of polonium and radium.
Surprise followed surprise when it was found that the radioactive atoms changed their chemical identity with time. Intense study of the phenomenon led to the theory of radioactive decay developed by Rutherford in 1903.
Marie and Pierre Curie after having worked for a while with radioactive materials, noticed that their fingers were reddened and swollen, and that the skin was peeling off. Becquerel carried a small tube with radium in it in his waistcoat pocket and was surprised to find a burn on his chest. Other early workers also reported about the burns and injuries of various kinds.
The strange fact about radiation is that it can harm without causing pain, which is the warning signal we expect from injuries. Pain makes us pull back our hands from flame or a very hot object, but a person handling radioactive materials has no way of telling whether he is touching something too “hot” for safety. Besides, the burns or other injuries that radioactivity produces may not appear for weeks.
Today scientists are aware of these dangers. They are steadily finding new means of protecting themselves and others from radioactivity. It may well be that in the race between production of radioactivity and production of means of protection, the second will be the winner.
Our modern atomic laboratories are built for safety. Their walls are very thick. The rooms in which radioactivity is handled are separated from others by heavy lead doors. Large signs reading “Danger – Radiation” indicate the unsafe parts of the buildings. Counters and other instruments are continuously measuring the radiation and give off special signals when it becomes too strong. Each worker carries a special badge that shows the amount of radiation he has been exposed to.
In the room in which radioisotopes are separated and handled, workers may wear plastic clothes that look like divers suits. They may handle the material under water with long tools; water is known to stop the radiation and protect the workers.
All radioisotopes are prepared by some method of remote control. They are placed inside heavy lead containers through which the radiation cannot pass, and shipped to where they are used.
Radioisotopes in Industry
The radiation emitted by radioisotopes is being utilized in a variety of useful ways. One way is measuring or testing industrial products, another is tracing the most complicated chemical reactions, still another is producing that for the generation of electric power. Radioisotopes often do a job better than conventional methods do. Sometimes they do jobs conventional devices can’t do at all. Since their radiation can easily be followed radioisotopes are being widely used as tracers.
We know of the petroleum industry being an early user of radioisotopes to transport different liquids and oil. A radioisotope was placed between different liquids or grades of petroleum signals where the flow of one product ends and the other begins. Radiation from the isotope also indicates the rate of flow along the length of the pipeline. By using this tracer method the engineers today are able to examine parts of various engine designs after testing, to learn facts about their wear and the efficiency of lubricants. Radioisotopes are widely employed in thickness gauges for all sorts of coated materials which are manufactured in continuous rolling sheets. In such a gauge a radiation beam from an isotope is passed through or reflected from the material being manufactured. Even the tiniest variation in the thickness will result in varying the strength of this beam and in a reading of the gauge. Gauge readings are fed electronically into a device that automatically adjusts the manufacturing process so as to ensure the correct thickness of the material.
Radiation gauges have the advantage of eliminating mechanical contact with the material being measured. They also give an accurate and uninterrupted reading no matter how fast the sheet flows. We have mentioned of radioisotopes being used to trace chemical reactions. Moreover radiation itself is used to change the molecular structure of substances, the materials with new properties being obtained. Many plastics products now in use have undergone this treatment. Plastics treated by radiation can be stronger, more heat-resistant and easier to dye.
Everyone knows of chemical batteries losing their power after a time, especially under constant use. Radioisotopes give off heat as well as radiation and this heat can readily be converted into a steady and long-lasting supply of electric current by means of a device known as a thermocouple. The current thus generated can be used to continuously recharge conventional batteries.
Thus, it is radioisotopes that are capable of supplying electric power for years. It may be expected that other radioisotopic devices will be utilized one day for providing reliable and long-lasting sources of electricity for spaceships during manned flights.
Ever since it became apparent that the supply of coal, oil and nature gas would soon become inadequate for our needs, scientists have intensified their search for other sources of energy. It is natural, then, that the investigators should turn to the Sun which has been providing the Earth with enormous quantities of energy in the form of light and heat ever since it was created.
The Sun is the most important body in the Universe for mankind, for it gives us heat without which the Earth would be frozen world in which no life can exist. The Sun is our closest star. Of course, you never should look directly at the Sun on a clear day. Although it is 93,000,000 miles away, it is so bright that it would damage your eyes.
The Sun is really a huge globe with a diameter of about 865,000 miles. It would take over 100 Earths, side by side, to reach across the Sun at the equator. If the Sun were a hollow ball, you could pack more than 1,300,000 Earths inside it.
It was natural for early man to regard the Sun as a God. Indeed, it would have been strange if they had not done so, since we depend entirely upon the Sun for our light and heat, and without it no life on Earth could ever have developed.
A better idea of the Sun’s size will be gained if we describe a simple though impossible experiment. Suppose, that we could take an aeroplane to the Sun, and fly once round the solar equator, moving at a steady speed of 500 mph; how long would it take us to go once round the Sun? The answer is surprising: it would take us 230 days. For almost eight months we would fly at this tremendous rate before arriving back at our starting point. Yet to go round the Earth at the same speed would take us only a little more than 50 hours.
The Sun’s mass is over 330,000 times that of the Earth, and the gravitational pull is extremely strong. If a man could stand on the solar surface, he would seem to weigh 2 tons, so that he would be crushed under his own weight. However, we can hardly hope to visit the Sun, where the surface temperature is almost 6,000 degrees Centigrade.
Until it became possible to form some ideas of the size of the Universe, men were inclined to think that the solar system was really important – just as a man who has lived all his life in a remote country village may think that the scattered houses which make up his own village are far more important than distant London. Nowadays, we know the solar system to be merely our “village in space”.
Choosing an Email Client
Email client software lets you connect to your email account and download emails. It also lets you create emails which you can send later. An email client stores all emails on your system, allowing you to sort and manage the email messages in the way you want. Many email clients also allow you to personalize your messages using pictures and templates. An email client should do more than simply allow you to send and receive emails. Many email clients added features that allow you to sort through and manage emails. You can create folders and subfolders so you can categorize your incoming and outgoing mail.
Email is notoriously unsecured. Email messages are prone to viruses and are used to spread malware and spyware. Some email clients are more susceptible to viruses than other programs. In general, the more commonly used email interfaces are the ones that are the least secure. This is simply because there are millions of messages being transmitted using these programs each day. The sheer volume of numbers makes using these email clients a greater risk. When looking at which email client to use, make sure the one you choose has a level of security built into the system. This should include things such as firewalls and anti-virus programs.
Another consideration is how an email client deals with spam. Spam is generally referred to as unwanted mail. Much like junk mail used to clog up physical mailboxes, spam clogs up email inboxes. Email is an easy and affordable way to send out bulk mail and unfortunately, too many companies take advantage of this. They collect email addresses and just randomly send out junk mail to everyone on the list. As with viruses, certain email clients are more prone to spam mail than others. When looking around at different options, make inquiries as to what protection the system has against spam mail. Receiving spam mail is mostly annoying but it can also be harmful to your computer as it could contain spyware or viruses.
Simply assess the tasks that you perform and rate them in order of frequency. For your email client to aid you in your everyday tasks, you first need to define what those tasks are. If you send pictures or sound files, then look for mail clients that specialize in making it easy to include these in mail. List the features that each email client offers. These features will be the major source of information to match your needs to particular mail client. If you need an address book and one or two of the clients don't offer them, then eliminate them from the list of possibilities.
Choose the email client that you have determined will meet your needs. Remember that you are never stuck with email client. You always have the ability to change to another if you find that the one you picked, for some reason, fails to deliver.