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welding, gas-shielding arc welding, gas welding, electron-beam welding and plasma-jet welding. In all processes the source of heat is an electric arc whose temperature may be as 5727 degrees Centigrade.

In the process of manual metal-arc welding an arc is established between the work and a metallic wire, or electrode, clamped in a holder. The intense heat of the arc melts some of the parent metal and the tip of the electrode. The molten metal fills the groove between the edges of the work and, on cooling, forms the weld. The metal electrode may have a covering to form a blanket of gas around the weld pool so as to protect it against the harmful effects of atmospheric oxygen and nitrogen.

During the manual gas-shielding arc welding with a nonconsumable electrode the gas is fed into the arc zone through a nozzle inside which is held an electrode (usually a tungsten one). An arc strikes between the edges, a filler wire is introduced into the joint.

The electroslag welding depends fro its effect on the heat generated by the passage of an electric current trough the electrode to the workpiece through a granulated welding composition (flux or slag). The workpiece is set up vertically with a large gap between the edges. The electrode and the flux are fed into the welding zone automatically. The intense heat generated by the passage of current melts both the electrode and the edges of workpiece, the copper blocks shape them as required and a weld forms when the molten metal cools. This process is especially advantageous on thicknesses of 1000 mm and more.

The source of heat in gas welding is high-temperature flame produced by the combustion of a fuel gas in oxygen. The edges of the work are melted by the flame, the flame simultaneously melts the tip of the filler wire introduced into the flame of the torch. This method is applicable to cast iron, non-ferrous and light-gauge steels.

Дайте відповіді на запитання.

1. What are the most applied processes in fusion welding?

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2.Why are they classified as one type?

3.How is the weld formed?

4.What is the peculiarity of the manual gas-shielding welding?

5.What is the source of heat in gas welding?

2.8.3. Машинобудівний факультет

PLANERS

A planer is a type of metalworking machine tool that uses linear relative motion between the workpiece and a single-point cutting tool to machine a linear toolpath. Its cut is analogous to that of a lathe, except that it is linear instead of helical. A planer is analogous to a shaper, but larger, and with the entire workpiece moving on a table beneath the cutter, instead of the cutter riding a ram that moves above a stationary workpiece. The table is moved back and forth on the bed beneath the cutting head either by mechanical means, such as a rack and pinion drive or a leadscrew, or by a hydraulic cylinder. The size of the plaper is determined by the nmaximum stroke of its ram.

The most common applications of planers are linear-toolpath ones, such as:

-Generating accurate flat surfaces. While not as precise as grinding, a planer can remove a tremendous amount of material in one pass with high accuracy.

-Cutting slots. Starting from a drilled or cored hole, a planer with a boring-bar type tool can cut internal features that don't lend themselves to milling or boring (such as irregularly shaped holes with tight corners) Planers and shapers are now obsolescent, because other machine tools (such as milling machines, broaching machines, and grinding machines) have eclipsed them as the tools of choice for doing such work. However, they have not yet disappeared from the metalworking world. Planers are used by smaller tool and die shops within larger production facilities to maintain and repair large stamping dies and plastic injection molds. Additional uses include any other task where an abnormally large block of metal must be squared when a (quite massive) horizontal grinder or floor mill is

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unavailable, too expensive, or otherwise impractical in a given situation. As usual in the selection of machine tools, an old machine that is in hand, still works, and is long since paid-for has substantial cost advantage over a newer machine that would need to be purchased. This principle easily explains why "old-fashioned" techniques often have a long period of gradual obsolescence in industrial contexts, rather than a sharp drop-off of prevalence such as is seen in mass-consumer technology fashions. There are two types of planers for metal: double-housing and open-side. The doublehousing variety has vertical supports on both sides of its long bed; the open-side variety has a vertical support on only one side, allowing the workpiece to extend beyond the bed. Metal planers can vary in size from a table size of 30"×72" to 20'×62', and in weight from around 20,000 lbs to over 1,000,000 lbs.

Дайте відповіді на запитання.

1.What is the difference between a planer and a shaper?

2.How is the size of the planer determined?

3.What are the most common applications of shapers and planers?

4.What differs double-housing and open-side planers?

5.Why are planers and shapers now obsolescent?

2.8.4. Транспортний факультет

TRAFFIC

Traffic on roads may consist of pedestrians, ridden or herded animals, vehicles, streetcars and other conveyances, either singly or together, while using the public way for purposes of travel. Traffic laws are the laws which govern traffic and regulate vehicles, while rules of the road are both the laws and the informal rules that may have developed over time to facilitate the orderly and timely flow of traffic.

Organized traffic generally has well-established priorities, lanes, right-of-way, and traffic control at intersections. Traffic is formally organized in many jurisdictions, with marked lanes, junctions, intersections, interchanges, traffic signals, or signs. Traffic

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is often classified by type: heavy motor vehicle (e.g., car, truck); other vehicle (e.g., moped, bicycle); and pedestrian. Different classes may share speed limits and easement, or may be segregated. Some jurisdictions may have very detailed and complex rules of the road while others rely more on drivers' common sense and willingness to cooperate.

Organization typically produces a better combination of travel safety and efficiency. Events which disrupt the flow and may cause traffic to degenerate into a disorganized mess include: road construction, collisions and debris in the roadway. On particularly busy freeways, a minor disruption may persist in a phenomenon known as traffic waves. A complete breakdown of organization may result in traffic jams and gridlock. Simulations of organized traffic frequently involve queuing theory, stochastic processes and equations of mathematical physics applied to traffic flow.

Rules of the road are the general practices and procedures that road users are required to follow. These rules usually apply to all road users, though they are of special importance to motorists and cyclists. These rules govern interactions between vehicles and with pedestrians. As a general rule, drivers are expected to avoid a collision with another vehicle and pedestrians, regardless of whether or not the applicable rules of the road allow them to be where they happen to be.

In addition to the rules applicable by default, traffic signs and traffic lights must be obeyed, and instructions may be given by a police officer, either routinely (on a busy crossing instead of traffic lights) or as road traffic control around a construction zone, accident, or other road disruption.

In many countries, the rules of the road are codified, setting out the legal requirements and punishments for breaking them. In Ukraine the rules are set out in the Highway Code, which includes obligations but also advice on how to drive sensibly and safely.

Дайте відповіді на запитання.

1. What is traffic?

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2.What and who do the traffic laws concern?

3.How is traffic organized?

4.What can cause traffic to disintegrate?

5.Are the traffic rules applied by default?

2.8.5. Факультет інформаціонно-обчислювальної техніки

COMPUTER VIRUSES

A computer virus is a computer program that can copy itself and infect a computer. The term "virus" is also commonly but erroneously used to refer to other types of malware, including but not limited to adware and spyware programs that do not have the reproductive ability. A true virus can spread from one computer to another (in some form of executable code) when its host is taken to the target computer. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.

As stated above, the term "computer virus" is sometimes used as a catch-all phrase to include all types of malware, even those that do not have the reproductive ability. Malware includes computer viruses, computer worms, Trojan horses, most rootkits, spyware, dishonest adware and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with worms and Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself automatically to other computers through networks, while a Trojan horse is a program that appears harmless but hides malicious functions. Worms and Trojan horses, like viruses, may harm a computer system's data or performance.

Viruses can be divided into two types based on their behavior when they are executed. Nonresident viruses immediately search for other hosts that can be infected, infect those targets, and finally transfer control to the application program they infected. Resident viruses do not search for hosts when they are started. Instead, a resident virus loads itself into memory on execution and transfers control to the host program. The virus stays active in the background

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and infects new hosts when those files are accessed by other programs or the operating system itself.

In order to avoid detection by users, some viruses employ different kinds of deception. Some old viruses make sure that the "last modified" date of a host file stays the same when the file is infected by the virus. Some viruses can infect files without increasing their sizes or damaging the files. They accomplish this by overwriting unused areas of executable files. These are called cavity viruses.

There are two common methods that an anti-virus software application uses to detect viruses. The first is using a list of virus signature definitions. This works by examining the content of the computer's memory (its RAM, and boot sectors) and the files stored on fixed or removable drives (hard drives, floppy drives), and comparing those files against a database of known virus "signatures". The disadvantage of this detection method is that users are only protected from viruses that pre-date their last virus definition update. The second method is to use a heuristic algorithm to find viruses based on common behaviors. This method has the ability to detect novel viruses that anti-virus security firms have yet to create a signature for.

Дайте відповіді на запитання.

1.What is a virus?

2.What are the infection strategies?

3.What are the methods to avoid detection?

4.What is the difference between a virus and a worm or a Trojan horse?

5.What are the methods of virus detection?

2.8.6. Факультет радіо приладобудування

DIODES

In electronics, a diode is a two-terminal electronic component that conducts electric current in only one direction. The term usually refers to a semiconductor diode, the most common type today. This

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is a crystalline block of semiconductor material connected to two electrical terminals. A vacuum tube diode is a vacuum tube with two electrodes; a plate and a cathode.

The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction) while blocking current in the opposite direction (the reverse direction). Thus, the diode can be thought of as an electronic version of a check valve. This unidirectional behavior is called rectification, and is used to convert alternating current to direct current, and to extract modulation from radio signals in radio receivers.

Diodes were the first semiconductor electronic devices. The discovery of crystals' rectifying abilities was made by German physicist Ferdinand Braun in 1874. The first semiconductor diodes, called cat's whisker diodes were made of crystals of minerals such as galena. Today most diodes are made of silicon, but other semiconductors such as germanium are sometimes used.

There are several types of junction diodes, which either emphasize a different physical aspect of a diode often by geometric scaling, doping level, choosing the right electrodes, are just an application of a diode in a special circuit, or are really different devices like the Gunn and laser diode and the MOSFET:

-cat’s whisker or crystal diodes are a type of point-contact

diode. The cat’s whisker diode consists of a thin or sharpened metal wire pressed against a semiconducting crystal, typically galena or a piece of coal. The wire forms the anode and the crystal forms the cathode. Cat’s whisker diodes were also called crystal diodes and found application in crystal radio receivers;

-avalanche diodes conduct in the reverse direction when the reverse bias voltage exceeds the breakdown voltage;

-laser diodes are commonly used in optical storage devices and for high speed optical communication;

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-photodiodes are intended to sense light (photodetector), so they are packaged in materials that allow light to pass, and are usually PIN (the kind of diode most sensitive to light);

-Varicap diodes are used as voltage-controlled capacitors.

The first use for the diode was the demodulation of amplitude modulated (AM) radio broadcasts. Rectifiers are constructed from diodes, where they are used to convert alternating current electricity into direct current. Diodes can be combined with other components to construct AND and OR logic gates. A diode can be used as a temperature measuring device, since the forward voltage drop across the diode depends on temperature Diodes will prevent currents in unintended directions. Diodes are also used in electronic musical keyboards.

Дайте відповіді на запитання.

1.What is a diode?

2.What is its application field?

3.What are the types of junction diodes?

4.What does a diode serve for?

5.When was a diode discovered?

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Варіант №3

3.1. Перепишіть речення та перекладіть рідною мовою. Визначте тип умовного речення.

3.1.1.Unless the depth of the insert had been sufficient, it would not have been possible to make a large number of regrinds.

3.1.2.If a small torch bulb is joined to the terminals, the bulb will light up for a time, but soon it will become dim and go out.

3.1.3.If the core were solid it would form a closed path of very low reluctance.

3.1.4.Were the surface of the bearings harder and smoother the loss of the power would be less.

3.1.5.If a resistance is connected to the circuit the strength of current will decrease.

3.2. Поставте дієслово у дужках в потрібному часі, зважаючи на тип умовного речення. Перекладіть речення рідною мовою.

3.2.1.They (not to go) tomorrow if it rains.

3.2.2.I should be disappointed if you (not to come).

3.2.3.I (to drive) to the country if the weather were fine.

3.2.4.If I had known that it was going to rain, I (to take) an umbrella.

3.2.5.Unless we (to buy) tickets today, there will be no spare ones tomorrow.

3.3. Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на незалежний дієприкметниковий комплекс (The Absolute Participle Complex).

3.3.1.Steel being one of the strongest metals, we use it for products where great strength is required.

3.3.2.The time of the beam`s travel and the velocity being known, the scientists were able to calculate the distance to different parts of the Moon`s surface with great precision.

3.3.3.This cycle is continued in each of the cylinders of the engine, the working strokes being so arranged that the crankshaft turns evenly.

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3.3.4.It has two limitations, one being the small combustion space, the other being the limited total area of heating surface.

3.3.5.We have many polymers, new methods of their applying being worked out gradually.

3.4. Перепишіть речення, перекладіть речення англійською мовою, вживаючи незалежний дієприкметниковий комплекс

(The Absolute Participle Complex).

3.4.1.Довжина пластини була достатньою, можна було зробити більш розрізів.

3.4.2.Коли роботу було закінчено, працівники пішли додому.

3.4.3.Температура повітря зростала, тому робітники включили кондиціонер.

3.5. Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на об’єктний інфінітивний комплекс

(Complex Object).

3.5.1.Did you feel the bridge shake?

3.5.2.The handle is expected to be turned c.c.w. and raised to enable the cutter to be turned around.

3.5.3.We consider ourselves to have the right to claim an allowance of 10 %.

3.5.4.Put on a thicker uniform, I don`t want you to catch a cold.

3.5.5.I heard the door open and somebody enter the shop.

3.6. Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на суб’єктний інфінітивний комплекс (Complex Subject). Перекладіть англійською мовою.

3.6.1.The rest of the goods are likely to be shipped in the first half of September.

3.6.2.This invention is considered of great importance

3.6.3.The acceleration is assumed to be negative when the braking force slows down the motion.

3.6.4.The secondary circuits are reported by the operator to have been arranged incorrectly.

3.6.5.The fracture seemed to be caused by a heavy blow.

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