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Методические указания и контрольные работы для студентов-заочников инженерного факультета (4 года обучения) Тверь-Сахарово 2005 (стр. 2 из 3)

Milk Pumps. The vacuum in the system is used to convey the milk from the cow to an adjacent receptacle where the milk can be released without breaking the vacuum. In the more complex plants the milk is pumped from the release point to the dairy. A small motor (up to about 2 hp) is used to drive the pump which is directly mounted on the motor shaft. Milk pumps are made from stainless steel and dismantle easily for cleaning. Totally-enclosed motors are used as it is usual for these units to be in damp, or even wet, situations. Starting can be direct on-line but it is important that a suitable starter is used to give protection.

ВАРИАНТ 2

1. Перепишите следующие предложения, подчеркните в каждом из них глагол-сказуемое и определите его видовременную форму и залог. Переведите предложения на русский язык. В разделе (б) обратите внимание на перевод пассивных конструкций.

а) 1. Today scientists are still looking for the substance as a source of energy.

2. I have known this fact since our meeting.

б) 1. This lecturer is listened to with great interest.

2. The intensity of this process is influenced by many factors.

II. Перепишите следующие предложения; подчеркните Participle I и Participle II и установите функции каждого из них, т.е. укажите, является ли оно определением, обстоя­тельством или частью глагола-сказуемого. Переведите пре­дложения на русский язык.

1. Molecular crystals are solids constructed of molecules held together by relatively weak forces.

2. The new materials recommended for soil construction were described in the article written by our professor.

3. Having been shown the way I found the office easily.

III. Перепишите следующие предложения; подчеркни­те в каждом из них модальный глагол или его эквивалент. Переведите предложения на русский язык.

1. Energy can exist in many forms and each form can be transformed into the other.

2. The computers should become an integral part of the orga­nization of industrial processes of all types.

3. Students are not allowed to smoke in the classrooms.

4. One should agree that the experiment was of great importance for our research.

IV. Перепишите и письменно переведите текст.

FEEDING SYSTEMS FOR LIVESTOCK FARMS

Mechanical feeding systems are becoming increasingly important in livestock farming. For a long time farmers have enjoyed the use of low-cost power and machinery in crop production, but until very recent years feeding has been an unmechanized and inefficient operation.

The present avail­ability and convenience of electric power at low cost makes it possible for every farm to eliminate shovel and basket feeding in favor of electrical and mechanical feeding systems. Such developments not only increase the individual farmer's output per man/hour, but change his role of a manual laborer.

Feeding systems consist usually of conveyors which carry the food from a bulk supply point into the house. The conveyors may be augers, chain-and-f light types or pneumatic pipe systems. Small motors from fractional horse power to 3 hp are necessary. Control is usually by a time switch.

A mechanical feeding system uses the energy of a machine to do work that was formerly done by human muscle power. An automatic feeding system supplies controls to machines so that they may function by themselves.

A mechanical feeding system, to be ideal, should indeed be completely automatic, that is, it should be set up so as to enable feed and supplements to move from storages to the feed bunk without any manual attention from the livestock operator. Such an ideal system - where grinders, blenders, conveyors, and distributors are per­fectly coordinated so that no manual attention is necessary - is sometimes unattainable, but should always be considered the goal when planning mechanical systems.

ВАРИАНТ 3.

I. Перепишите следующие предложения; подчеркните в каждом из них глагол-сказуемое и определите его видовременную форму и залог. Переведите предложения на русский язык. В разделе (б) обратите внимание на перевод пассивных конструкций.

а) 1. It is the car that will be the transport of the future.

2. Scientists have found ways of measuring the sizes and masses of bodies.

6) 1. Elements are transformed into other elements both by man and by nature.

2. The report will be improved by him by changing the end.

II. Перепишите следующие предложения; подчеркните Participle I и Participle II и установите функции каждого из них, т.е. укажите, является ли оно определением, обстоя­тельством или частью глагола-сказуемого. Переведите пре­дложения на русский язык.

1. He heard the voices coming through the open window.

2. A balsa tree found in South America is lighter than any other.

3. Soils containing too much sand or clay are of less value in agriculture.

4. When studying elements Mendeleyev found that they were divided into nine groups.

III. Перепишите следующие предложения; подчеркни­те в каждом из них модальный глагол или его эквивален­ты. Переведите предложения на русский язык.

1. She can tell you everything about cattle.

2. The application of digital (цифровой) computers should include all forms of automatic control in science and industry.

3. He had much work to do yesterday.

4. The team of experts is to study the present situation in agriculture.

IV. Перепишите и письменно переведите текст.

POULTRY REARING

Power is used in the poultry industry to drive fans for incubation, ventilation, the feeding system, egg collection and grading. In the main, single power units are small and installations often use several fractional horse power motors.

Incubators. In all but the smallest incubators, fans or air circulators of paddle type are used to move air gently round the eggs. The fans are slow-speed units and paddles, when used, are driven through belt or chain drive or geared motors.

Ventilation. By using ventilating fans temperature and humidity can be kept within generally acceptable limits. There are many different types of ventilation systems.

Very broadly, the systems fall within two groups, one using small multi-fan units and the other, large single fans with a distribution duct system. Both groups can extract air from the house, or the house can be «pressurized», i.e. fan (fans) blows air into the house and the stale air is ex­hausted from separate outlets. Whatever the system, a good even distribution of air going into the house is essential. Ventilation rates are calculated according to the number and type of birds being housed with control by temperature. Speed of fans can be controlled by thermostat, with some fans in a multi-fan installation being stopped by a further thermo­stat if a very low ventilation rate is required, but care must be taken that air distribution is not upset.

Feeding and Egg Collection. Feeding systems consist usually of conveyors which carry the food from a bulk supply point into the house. The conveyors may be augers, chain-and-f light types or pneumatic pipe systems. Small motors from fractional horse power to 3 hp are necessary. Control is usually by a time switch.

Mechanical collection of eggs, by an endless belt from the point of lay to a central position, is sometimes employed as well as mechanical grading. Small motors, up to 1 or 2 hp, are usually sufficient.

ВАРИАНТ 4.

I. Перепишите следующие предложения; подчеркните в каждом из них глагол-сказуемое и определите его видовременную форму и залог. Переведите предложения на русский язык. В разделе (б) обратите внимание на перевод пассивных конструкций.

а) 1. He has forgotten his English since he graduated the Academy.

2. The problem of the structure of matter is constantly occu­pying the minds of many scientists.

б) 1. Fifty students were admitted to the faculty last August.

2. Many compounds can be decomposed when they are acted upon by different forms of energy.

II. Перепишите следующие предложения; подчеркните Participle I и Participle II и установите функции каждого из них, т.е. укажите, является ли оно определением, обстоя­тельством или частью глагола-сказуемого. Переведите пре­дложения на русский язык.

1. They reminded at home refusing to go anywhere that day.

2. Matter composed of any chemical combination of elements is called a compound.

3. The smallest particle having all the characteristics of an el­ement is called an atom.

4. When started and completed its construction became the best.

III. Перепишите следующие предложения; подчеркни­те в каждом из них модальный глагол или его эквивалент. Переведите предложения на русский язык.

1. Heat can be divided into three different types.

2. He was to stay at the office until the report was ready.

3. Chemical means had to be used for the separation of com­pounds into their elements.

4. The existence of this theory laser in the future may be possi­ble.

IV. Перепишите и письменно переведите текст.

DISK TILLERS

These tools are designed for both tillage and seeding. They consist of a single gang of disk blades, 20 to 26 in. in diameter, on a common axle, all throwing the soil the same way. The common axle differentiates these tools from regular disk plows which have the disk blades tipped back, necessi­tating separate axles and bearings for each blade.

Disk tillers are made as small as two-blade models cutting 15 in. wide up to models cutting 20 ft wide. They are highly economical of power. Seeding boxes are available for some models, enabling seed-bed preparation and wheat seeding to be done in one operation.

The forces acting on a disk tiller are similar to those act­ing on .a plow except that the resultant lengthwise soil force on the blades is usually upward, requiring extra weight for penetration.

Trail-type disk tillers usually permit the angle of attack of the disk gang to be adjusted from 40 to 55°. In hard high-draft soil, penetration can be improved and width of cut de­creased by increasing the angle, while maximum width can be taken with less angle in loose easy-working soils. This adjustment is provided by changing the angle of the land wheel and the furrow wheels with respect to the disk gang.

Hitching principles are similar to those for mold-board plows. The centre of draft is at the centre disk blade slight­ly below the surface of the ground.

Disk tillers are necessarily built heavier than mold-board plows and wheel weights can be added for penetration in hard soil.

ВАРИАНТ 5.

I. Перепишите следующие предложения; подчеркните в каждом из них глагол-сказуемое и определите его видовременную форму и залог. Переведите предложения на русский язык. В разделе (б) обратите внимание на перевод пассивных конструкций.

а) 1. Many students come to the Academy by their own cars.

2. Laser devices will apparently make it possible to build extremely fast computer elements.

б) 1. A new experiment will be finished soon.

2. The material was looked for many scientific books.

II. Перепишите следующие предложения; подчеркните Participle I и Participle II и установите функции каждого из них, т.е. укажите, является ли оно определением, обстоя­тельством или частью глагола-сказуемого. Переведите пре­дложения на русский язык.

1. It’s not only an efficient tool for studying the physical properties of solids.

2. Having obtained the necessary results they stopped their experimental work.

3. When translated, his article was sent to the ICC.

4. All the houses made of wood were burning like paper.

III. Перепишите следующие предложения; подчеркни­те в каждом из них модальный глагол или его эквивалент; предложения переведите.

1. A mechanical feeding system should be completely automatically.

2. The water that comes to the field must get to the roots of every plant.

3. The best way of keeping the bull is to have a special barn for him.

4. Man could improve the soil using and discovering more kinds of soils.

IV. Перепишите и письменно переведите текст.

ELECTRIC MOTORS

The electric motor is a simple machine which will provide power quietly and smoothly, without fumes. It is a clean source of mechanical power, requires very little attention, and can be run continuously for long periods at a constant speed and with the minimum of maintenance.

Electric motors can be started and stopped by the touch of a button and full power is available from the moment that the motor is started. The fire risk is very low and the motor can be placed almost anywhere. Electric motors use energy only while they are running.

The open frame type of electric motor is the simplest design but it is not recommended for use on farms. Most farm motors need to be of the enclosed surface-cooled type which prevents dust and moisture from entering the windings.

Refrigeration is now generally accepted as essential for cooling milk, an operation which must be carried out as soon as possible after the milk has left the cow.

The type of cooling varies between (1) surface coolers which the chilled water passes through the cooler and the milk passes over the exterior surface; (2) in-can cooling with pumped chilled water cascading down the outside of the an and (3) a jacketed bulk tank with an evaporation coil within the jacket.

In each case the size of motor required is directly related to the quantity of milk to be cooled after each milk­ing. Commercial-type compressors are used with standard mo­tors which should be totally enclosed.

A motor may be chosen with regard to the maximum load to be placed on the motor: this may lead to the equipment being over-motored with consequent loss of efficiency, coupled with a lower power factor.