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bedmill, however, the table moves only perpendicular to the spindle's axis, while the spindle itself moves parallel to its own axis.
A horizontal mill has the same sort of x–y table, but the cutters are mounted on a horizontal arbor across the table. A majority of horizontal mills also feature a +15/-15 degree rotary table that allows milling at shallow angles. Because the cutters have good support from the arbor, quite heavy cuts can be taken, enabling rapid material removal rates. These are used to mill grooves and slots. Plain mills are used to shape flat surfaces. Special cutters can also cut grooves, bevels, radii, or indeed any section desired. These specialty cutters tend to be expensive.
Дайте відповіді на запитання.
1.What kinds of milling machines can you name?
2.What kinds of operations can they perform?
3.Why is there no evidence of milling machines development?
4.Is the position of the spindle stationary?
5.Explain the difference between vertical and horizontal machines.
1.8.4. Транспортний факультет
TRANSPORT FORECASTING
Transportation forecasting is the process of estimating the number of vehicles or travelers that will use a specific transportation facility in the future. A forecast estimates, for instance, the number of vehicles on a planned freeway or bridge, the ridership on a railway line, the number of passengers patronizing an airport, or the number of ships calling on a seaport. Traffic forecasting begins with the collection of data on current traffic. Together with data on population, employment, trip rates, travel costs, etc., traffic data are used to develop a traffic demand model. Feeding data on future population, employment, etc. into the model results in output for future traffic, typically estimated for each segment of the transportation infrastructure in question, e.g., each roadway segment or each railway station.
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Traffic forecasts are used for several key purposes in transportation policy, planning, and engineering: to calculate the capacity of infrastructure, e.g., how many lanes a bridge should have; to estimate the financial and social viability of projects, e.g., using cost-benefit analysis and social impact assessment; and to calculate environmental impacts, e.g., air pollution and noise.
Within the rational planning framework, transportation forecasts have traditionally followed the sequential four-step model or urban transportation planning procedure. Land use forecasting sets the stage for the process. Typically, forecasts are made for the region as a whole, e.g., of population growth. Such forecasts provide control totals for the local land use analysis. Typically, the region is divided into zones and by trend or regression analysis, the population and employment are determined for each.
The four steps of the classical urban transportation planning system model are:
-trip generation determines the frequency of origins or destinations of trips in each zone by trip purpose, as a function of land uses and household demographics, and other socio-economic factors;
-trip distribution matches origins with destinations, often using a gravity model function, equivalent to an entropy maximizing model;
-mode choice computes the proportion of trips between each origin and destination that use a particular transportation mode;
-route assignment allocates trips between an origin and destination by a particular mode to a route.
After the classical model, evaluative decision criteria are applied. A typical criterion is cost-benefit analysis. Such analysis might be applied after the network assignment model identifies needed capacity: is such capacity worthwhile? In addition to identifying the forecasting and decision steps as additional steps in the process, it is important to note that forecasting and decisionmaking permeate each step in the UTP process. Planning deals with the future, and it is forecasting dependent.
Дайте відповіді на запитання.
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1.What does a traffic forecasting serve for?
2.What does it begin with?
3.What is the 4 step model of the urban transportation planning procedure?
4.Which segment of the infrastructure is the data estimated for?
5.What is a traffic demand?
1.8.5. Факультет інформаціонно-обчислювальної техніки
OPERATING SYSTEMS
An operating system (OS) is the software on a computer that manages the way different programs use its hardware, and regulates the ways that a user controls the computer. An OS is a master control program which controls program which controls the functions of the computer system as a whole and the running of application programs. Operating systems are found on almost any device that contains a computer with multiple programs—from cellular phones and video game consoles to supercomputers and web servers. Some popular modern operating systems for personal computers include Microsoft Windows, Mac OS X, and Linux.
The components of an operating system all exist in order to make the different parts of a computer work together. All software— from financial databases to film editors—needs to go through the operating system in order to use any of the hardware, whether it be as simple as a mouse or keyboard or complex as an internet connection.
An operating system can be divided into many different parts. One of the most important parts is the kernel, which controls lowlevel processes that the average user usually cannot see: it controls how memory is read and written, the order in which processes are executed, how information is received and sent by devices like the monitor, keyboard and mouse, and deciding how to interpret information received by networks. Outside of firmware, the operating system provides the most basic level of control over the hardware. It manages memory addresses in the RAM, it controls which processes access the different modes of the CPU, and it organizes the data on disks with file systems. These not only
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streamline the ability of many different programs to be run at once on all of these parts; it also makes sure that faulty or malicious code does not damage the hardware.
The user interface is the part of the operating system that interacts with the computer user directly, allowing them to control and use programs. The user interface may be graphical with icons and a desktop, or textual, with a command line. Many computer operating systems allow the user to install or create any user interface they desire.
Interrupts are central to operating systems, as they provide an efficient way for the operating system to interact with and react to its environment. The alternative—having the operating system "watch" the various sources of input for events (polling) that require action— can be found in older systems with very small stacks (50 or 60 bytes) but fairly unusual in modern systems with fairly large stacks. Interrupt-based programming is directly supported by most modern CPUs. Interrupts provide a computer with a way of automatically saving local register contexts, and running specific code in response to events.
Currently most operating systems support a variety of networking protocols, hardware, and applications for using them. This means that computers running dissimilar operating systems can participate in a common network for sharing resources such as computing, files, printers, and scanners using either wired or wireless connections.
Дайте відповіді на запитання.
1.What is an operating system?
2.Which operating systems are wide-spread?
3.Can you name the OS components?
4.What does the kernel control?
5.Which components helps to interact with the environment?
1.8.6. Факультет радіо приладобудування
RADIO
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Radio is the transmission of signals by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space. Information is carried by systematically changing (modulating) some property of the radiated waves, such as amplitude, frequency, phase, or pulse width. When radio waves pass an electrical conductor, the oscillating fields induce an alternating current in the conductor. This can be detected and transformed into sound or other signals that carry information.
Radio systems used for communications will have the following elements. With more than 100 years of development, each process is implemented by a wide range of methods, specialized for different communications purposes.
Each system contains a transmitter. This consists of a source of electrical energy, producing alternating current of a desired frequency of oscillation. The transmitter contains a system to modulate (change) some property of the energy produced to impress a signal on it. This modulation might be as simple as turning the energy on and off, or altering more subtle properties such as amplitude, frequency, phase, or combinations of these properties. The transmitter sends the modulated electrical energy to a tuned resonant antenna; this structure converts the rapidly changing alternating current into an electromagnetic wave that can move through free space (sometimes with a particular polarization).
Electromagnetic waves travel through space either directly, or have their path altered by reflection, refraction or diffraction. The intensity of the waves diminishes due to geometric dispersion (the inverse-square law); some energy may also be absorbed by the intervening medium in some cases. Noise will generally alter the desired signal; this electromagnetic interference comes from natural sources, as well as from artificial sources such as other transmitters and accidental radiators. Noise is also produced at every step due to the inherent properties of the devices used. If the magnitude of the
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noise is large enough, the desired signal will no longer be discernible; this is the fundamental limit to the range of radio communications.
The electromagnetic wave is intercepted by a tuned receiving antenna; this structure captures some of the energy of the wave and returns it to the form of oscillating electrical currents. At the receiver, these currents are demodulated, which is conversion to a usable signal form by a detector sub-system. The receiver is "tuned" to respond preferentially to the desired signals, and reject undesired signals.
Early radio systems relied entirely on the energy collected by an antenna to produce signals for the operator. Radio became more useful after the invention of electronic devices such as the vacuum tube and later the transistor, which made it possible to amplify weak signals. Today radio systems are used for applications from walkietalkie children's toys to the control of space vehicles, as well as for broadcasting, and many other applications. Early uses were maritime, for sending telegraphic messages using Morse code between ships and land. Today, radio takes many forms, including wireless networks and mobile communications of all types, as well as radio broadcasting.
Дайте відповіді на запитання.
1.How is information carried?
2.What are the main radio systems elements?
3.What does a transmitter serve for?
4.How are the waves intercepted?
5.What can you tell about radio application?
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Варіант №2
2.1. Перепишіть речення та перекладіть рідною мовою. Визначте тип умовного речення.
2.1.1.This would not have been too much a problem if we had applied such atmospheres to presses and some forging machines.
2.1.2.If the cross-section of the conductor were slightly increased, it would cause the reduction of the resistance.
2.1.3.If an expedition to any other planet were possible it would result in highly important scientific data.
2.1.4.If the water falls from a great distance, its energy will be known to change from potential to kinetic.
2.1.5.They could have measured the voltage immediately, if they had connected a voltmeter to the circuit.
2.2. Поставте дієслово у дужках в потрібному часі, зважаючи на тип умовного речення. Перекладіть речення рідною мовою.
2.2.1.If I had money, I (to buy) that overcoat.
2.2.2.If you (to stay) here longer, you will see him.
2.2.3.If the goods had been loaded quickly, we (to receive) them in
time.
2.2.4.If you (to arrive) earlier, you would have found me there.
2.2.5.We shall be very sorry if he (not to call) on us tonight.
2.3. Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на незалежний дієприкметниковий комплекс (The Absolute Participle Complex).
2.3.1.The sand being not open grained, the gases will not escape from the mould rapidly enough, and blowholes will be formed in the casting.
2.3.2.The groove having been cut at 45 degrees, all the difficulties were overcome.
2.3.3.Quantum generators can focus light in extremely narrow beams, their angular width being in the order of thousands of degree.
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2.3.4.Plastics having been applied for interior decoration, we found them to be more practicable than some other materials.
2.3.5.The travelled distance having been given in meters and the time in seconds, speed was measured in m.p.s..
2.4. Перепишіть речення, перекладіть речення англійською мовою, вживаючи незалежний дієприкметниковий комплекс
(The Absolute Participle Complex).
2.4.1.Навантаження двигуна зростає та ковзання, пропорційне до навантаження, має місце.
2.4.2.Цей завод виробляє багато чавуну, при цьому більша його частина переробляється на сталь.
2.4.3.Станок було вимкнено, та оператор залишив цех.
2.5. Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на об’єктний інфінітивний комплекс
(Complex Object).
2.5.1.It is carelessness that allows losses to be greater.
2.5.2.We believed the programming to have been done very skillfully, so you might rely on the results to be exact.
2.5.3.The use of electric heating would enable all generators to be economically and efficiently serviced at a central depot.
2.5.4.I know gravity to act on every particle of a body so that its weight is actually distributed throughout the body .
2.5.5.We felt a good possibility utilize the new equipment for speeding up the process of calculation.
2.6. Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на суб’єктний інфінітивний комплекс (Complex Subject). Перекладіть англійською мовою.
2.6.1.This house appears to have been built by a good architect.
2.6.2.This price was considered to be very high.
2.6.3.The rapid increase in viscosity was found to be relatively independent of the temperature.
2.6.4.He is certain not to come.
2.6.5. The goods are known to have been shipped by this vessel on the 15th of May.
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2.7. Перекладіть англійською, вживаючи об’єктний інфінітивний комплекс (Complex Object) та суб’єктний інфінітивний комплекс (Complex Subject).
2.7.1. Можливо, ці інженери не готові до роботи з напівпровідниками.
2.7.2. Відомо, що він виконав план достроково.
2.7.3. Ми вважаємо, що побудуємо трубопровід до кінця тижня. 2.7.4. Механік спостерігав, як двигун набирає обертів.
2.7.5. Здавалось, вони не помітили дефект корпуса.
2.8. Перепишіть текст за фахом та перекладіть його рідною мовою.
2.8.1. Електротехнічний факультет
SQUIRREL-CAGE MOTORS
There are two types of AC motors, depending on the type of rotor used. The first is the synchronous motor, which rotates exactly at the supply frequency. The magnetic field on the rotor is either generated by current delivered through slip rings or by a permanent magnet.
The second type is the induction motor, which runs slightly slower than the supply frequency. The magnetic field on the rotor of this motor is created by an induced current. Most common AC motors use the squirrel cage rotor, which will be found in virtually all domestic and light industrial alternating current motors. The motor takes its name from the shape of its rotor "windings"- a ring at either end of the rotor, with bars connecting the rings running the length of the rotor. It is typically cast aluminum or copper poured between the iron laminates of the rotor, and usually only the end rings will be visible. The vast majority of the rotor currents will flow through the bars rather than the higher-resistance and usually varnished laminates. Very low voltages at very high currents are typical in the bars and end rings; high efficiency motors will often use cast copper in order to reduce the resistance in the rotor.
In operation, the squirrel cage motor may be viewed as a transformer with a rotating secondary. When the rotor is not rotating
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in sync with the magnetic field, large rotor currents are induced; the large rotor currents magnetize the rotor and interact with the stator's magnetic fields to bring the rotor almost into synchronization with the stator's field. An unloaded squirrel cage motor at rated no-load speed will consume electrical power only to maintain rotor speed against friction and resistance losses; as the mechanical load increases, so will the electrical load - the electrical load is inherently related to the mechanical load. This is similar to a transformer, where the primary's electrical load is related to the secondary's electrical load. Furthermore, a stalled squirrel cage motor (overloaded or with a jammed shaft) will consume current limited only by circuit resistance as it attempts to start. Unless something else limits the current (or cuts it off completely) overheating and destruction of the winding insulation is the likely outcome.
In order to prevent the currents induced in the squirrel cage from superimposing itself back onto the supply, the squirrel cage is generally constructed with a prime number of bars, or at least a small multiple of a prime number (rarely more than 2). There is an optimum number of bars in any design, and increasing the number of bars beyond that point merely serves to increase the losses of the motor particularly when starting.
Virtually every washing machine, dishwasher, standalone fan, record player, etc. uses some variant of a squirrel cage motor.
Дайте відповіді на запитання.
1.Why is the squirrel-cage motor named so?
2.What is the rotor made from?
3.Where do these motors find their application?
4.What device is it similar to?
5.What should one do to prevent the currents induced in the squirrel cage from superimposing itself back onto the supply?
2.8.2.Інженерно-фізичний факультет
FUSION WELDING
The field of fusion welding can be broken into several processes, the most important of which are arc welding, electroslag
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