Work in laboratories

There is an old proverb “Practice makes perfect” which means that an experienced specialist is able to cope with any шк.ГТо train such highly-qualified, skilled and creatively thinking specialists is the main purpose of our university. That is why the profound study of theory should be accompanied by practical training. There exist many ways of gaining practical skills in your field of specialization, while you are still studying for a degree. In most cases, practical training begins with the work in laboratories of the university and is completed at industrial enterprises of Lviv and Lviv

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region. Besides, you may participate in the work of students’ construction bureaux or take some relevant job during your summer vacations. But even if you don’t feel like working in summer, you are sure to acquire the necessary practical experience in specialized laboratories during the academic year.

There is a number of general laboratories in our university intended for practical work of students of all specialities, for example, the laboratories of physics and chemistry. In physics laboratories students investigate certain physical phenomena; carry out exercises in mechanics, optics, and molecular physics; measure electrical (voltage, frequency, resistance) and non-electrical (temperature, pressure, dimensions) quantities. One should be especially careful while working in chemical laboratories, because some substances are harmful or explosive.

Besides, each department of the university is provided with its own laboratory facilities, so that students could acquire skills according to the speciality chosen. Some laboratories are equipped with various apparatuses and measuring devices, while in others, computers of different generations are installed. The work in the laboratories enables students to (1) assess the practical value of their knowledge, (2) master the basic experimental techniques necessary for their further research activity, (3) learn how to handle modem equipment, (4) independently find solution to problems that arise in the process of work, and (5) analyse the results obtained. The laboratory experiments are carried out under the guidance of qualified teachers and in the presence of laboratory assistants. Before performing a laboratory work, students get acquainted with the instruction which contains the description of installations to be used and presents the order in which the lab exercise should be done and other useful information. After completing the work, students write down and analyse the results.

All the Departments of the university have laboratories equipped with computers, including Pentium computers with huge memory capacity and high processing speed. Before operating the computers, students listen to a course of lectures on means of data transfer, study fundamentals of computing techniques and programming. In these labo­ratories students are engaged in different kinds of activity. They learn how to handle computer hardware (keyboard, mouse and other input/output devices) and get acquain­ted with computer software. The lab exercises are given to students either as printed worksheets or in the form of files recorded on floppy disks. The answers are pre­programmed, and the students’ performance is evaluated automatically by computers. Besides, students may use the laboratory computers while working on their course and diploma projects: they do calculations, simulate processes and design new devices or constructions with the help of CAD (Computer-Aided Design) programs. If students need some additional information on the latest achievements in their field of study, they may use compact disks with Read-Only-Memory (CD ROM) or they may look for it in the Internet. The installed software is easy to use, and system prompts on the screen will help students to find the site in the Internet they are interested in.

So, English philosopher Francis Bacon was absolutely right, when he uttered his famous statement “Knowledge is power”. But you will never benefit from this power, unless you apply your theoretical knowledge to practice.

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Task 2.32. Read the text and answer the questions below it:

LABORATORY OF PRECISION DEVICES AND MEASURING INSTRUMENTS

Fine mechanisms and precision instruments have been known to people for ages, In the preceding centuries most of them were designed and produced by craftsmen. Although watches have been manufactured industrially since the middle of the nineteenth century, it was only in the 20"" century that the industrial production of different fine mechanisms and precision instruments was started.'Their production on a commercial scale gave rise to the scientific approach to their design and the need for highly qualified specialists in this branch of industry. Engineers and designers of precision mechanics are trained at our University. In the course of their training students study such special subjects as: instruments of precision mechanics, machine parts, strength of materials, electrical measurement of mechanical quantities etc. The syllabus is designed to provide the highest quality, up-to-date training and experience possible. The students of the senior courses benefit from the work at the Laboratory of Precision Devices and Measuring Instruments. Current research is centred on:

446. error control at precision weighing;

447. grading of thermocouple;

448. fatigue testing of spring material,

449. speed testing of air flow;

450. analysis of taxi en route performance by taximeter readings;

451. measuring of resistance using analogue and digital instruments;

452. studying of effects which can be utilized to provide reliable electrical measuring instruments;

453. drawing a circuit diagram for electrical energy measuring instruments;

454. taking up characteristics of internal combustion engine performance.

The laboratory has a wide range of devices necessary for research on designing and improving measuring instruments, as well as other items of test equipment.

Students study two types of instruments: analogue and digital. An analogue instrument, while measuring different quantities, indicates their value by the movement of a pointer across the face of a scale. A digital instrument gives a display on a screen in a set of numbers. Both types are portable, accurate and widely used, but digital instruments need a power supply, while analogue ones usually do nott The choice of the instrument depends on the value to be measured. Students use different types of instruments while carrying out the research.

In lab exercises dealing with determination of error at weighing, students use analytical balance of VA-200 type. It is an equal-arm balance for weighing quantifies below 200g. Systematic and accidental errors are unavoidable at weighing as they happen due to structural peculiarities of the balance. Accidental errors depend on many causes such as: temperature, vibrations, early or late readouts etc. The aim of the work carried out by the students is to eliminate all possible errors.

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While grading thermocouples, students compare the reading of the thermocouple tested with the reading of a mercurial thermometer.

The study of measuring devices is connected with research in automotive design and manufacture. Students work with taximeters used for automatic readQut of the sum to be paid by a passenger, tachometers used for measuring rotation speed, accelerome-ters, pressure transducers etc.

They also study measuring instruments designed for:

455. length measurement (dial gauges and micro-indicators);

456. time and velocity measurement (various types of clocks and watches, speedometers, revolution counters);

457. optical surveying and laboratory measurement (theodolites, polarimeters);

458. flow measurement (aircraft speedometers, tachometers etc.);

459. pressure measurement;

460. temperature measurement;

461. volume measurement (gas meters, water meters, petrol flow meters etc.).

Extensive research and development work has also been conducted in the technology of treatment of many special materials required for the development and manufacture of instruments for scientific and industrial use.

Work in the laboratory helps students to perfect their knowledge in special subjects, gives them an excellent start to their research and prepares them for future careers. Questions:

462. Since when have watches been manufactured industrially?

463. What gave rise to the need for scientific approach to the design of precision instruments?

464. What special subjects do the students of precision mechanics study?

465. What do students of senior courses do at the laboratory of precision devices and measuring instruments?

466. How does an analogue instrument indicate values?

467. What does the choice of an instrument depend on?

468. What device is used to determine errors at weighing?.

469. How is grading of thermocouple done?

470. What measuring instruments do students become acquainted with at the laboratory?

Task 2.33, Quiz. Choose the answers that suit you, calculate your score total and read the comments: