Grammar study: Indefinite, Continuous, Perfect in Active and Passive (repetition)

Cм. грамматику об этом в Section I и Section VII.

Text

Real the text describing hazards and precautions in specific areas:

Radiation safety

A number of acute and long term effects on humans have been related to exposure from various types of ionizing radiation. Radiation hazards arise when using radio-isotopes, lasers, x-ray generators and plasma torches. Each is hazardous in a unique way. A thorough knowledge of the device or the isotope which is to be used is mandatory. The precautions vary widely. Information pertaining to the particular hazard should be obtained from research staff member or technician in charge of the equipment prior to use. However, several precautionary procedures should always be followed:

a) Radioactive Materials

All work with radioactive material or radiation producing equipment must be registered with the Health Physics Office. All persons using radioactive material and x-ray machines must be instructed in the potential hazards and the necessary safety precautions. All persons working with radioactive materials or equipment must obtain radiation film badges and complete the training session before beginning their work. It is necessary to review any potential exposures to non-ionizing radiation such as ultraviolet, visible, infrared and microwave radiation. It is very important to clearly mark areas in which lasers, ultraviolet, or high intensity light sources are in use. It is also prescribed to wear eye protection appropriate to the type of radiation being used when working with these sources.

b) X-ray equipment

Persons using the x-ray equipment must have permission and instruction as to the safe use of this equipment. The door to the laboratory must be locked when it is not being used by authorized personnel. Under no circumstances should any part of the body be placed directly in primary x-ray beams. Never align samples with the eye in such a position that it might be exposed to the primary beam. Do not use any x-ray machine that is not working properly. Wear required personnel monitoring devices at all times while using the x-ray machine. Have the radiation levels around the x-ray machine checked anytime. Report any suspected overexposures to the supervising organization immediately. Do not depend upon lead foil or sheets for permanent shielding. Shields should be constructed of more durable materials. If lead is to be used it should be as a liner inside brass or some other material. And also remember the additional high voltage hazard associated with x-ray machines.

c) Lasers

There are many types (intensities) of lasers and therefore here only general guidelines are given:

• never look directly at the beam;

• do not allow any object which could cause specular reflections in or along the beam, such as buttons, screw heads, or jewelry;

• always wear goggles that offer protection against specific wavelength of the laser in use;

Warning signs outside and inside the laboratory should be posted to warn of potential hazards. And the areas where laser beams are in use should be clearly marked.

d) Ultraviolet lamps

It should be born in mind that all radiation of wavelength shorter than 350 mm must be considered dangerous. Protective safety glasses with UV absorbing lenses should be worn when the eyes may be accidentally exposed. Skin exposed to UV radiation can receive painful burns, analogous to sunburns and should be protected.

In manufacture processes also there are sources of radiation and the workers may be exposed to it. For example, the welding arc generates extremely intense radiation in the ultra-violet (UV), visible and infrared (IR) range of the electromagnetic spectrum. «Welder’s flash» or «arc eye» is a well-known condition resulting from excessive exposure of the eye to UV light. Medically, the condition is known as conjunctivitis. Its symptoms include swelling and redness of the eyes and a feeling that the eyeball is scratched. Exposure to UV and visible light has been related to an increased incidence of cataracts among welders. UV and IR radiation can cause skin burns similar to sun burn.

Controlling radiation exposure is important duty. A welder should never strike an arc without eye protection. In addition, welding areas should be surrounded by radiation screens to protect adjacent workers. But unfortunately many welding shops fail to take this simple precautions.

Not only x-rays, lasers, ultra-violet, infrared radiation and welding sparks can cause eye injuries. In metal – cutting manufactures the causes of eye injuries are flying particles: metal dust, metal chips. Not wearing eye protection in the workplace can result in injuries. Such accidents occur most often among craft workers, in industrial equipment operations in nearly every industry. It is necessary to think about possible eye hazards at each workplace.

Exercise 2. Define the tense of the verbs in the sentences:

1. A number of adverse (неблагоприятный) effects on humans have been related to exposure from radiation.

2. It is prescribed to wear eye protection appropriate to the type of radiation.

3. The door to the laboratory must be locked when it is not being used by personnel.

4. Do not use any x-ray machine that is not working properly.

5. In the passage “Lasers” only general guidelines are given.

6. The result from excessive exposure of the eye to UV light is known as conjunctivitis.

7. Its symptoms include a feeling that the eyeball is scratched.

8. Exposure to UV light has been related to an increased incidence of cataracts among welders.

9. Eye injuries often occur in industrial enterprises.

Exercise 3. Find in the text sentences that correspond to the following statements:

1. Many unfavourable effects are referred to radiation.

2. Radiation danger appears due to radioactive sources.

3. Excellent knowledge of apparatuses is obligatory.

4. The precautions by working with radioactive devices differ considerably.

5. Information about hazard should be given before using the equipment.

6. Places using radiation sources should be marked.

7. Persons working with radiation devices have to be allowed to work with them.

8. It is necessary to check the radiation level periodically.

9. As a rule, welders’ eyes are greatly exposed to UV light.

10. It is necessary to separate welding zones from other workplaces.

Exercise 4. Match synonyms in the right and left columns:

1. prior to	a) proper
2. mandatory	b) instruction
3. mark	c) ray
4. acute	d) glasses
5. to relate to	e) to connect
6. effect	f) by chance
7. hazardous	g) adverse
8. procedure	h) influence
9. beam	i) before
10.appropriate	j) dangerous
11.to permit	k) to happen
12.goggles	l) level
13.to associate	m) to allow
14.guideline	n) technique
15.accidentally	o) obligatory
16.range	p) sign
17.to occur	q) to refer to