2. Прочитайте текст снова и письменно ответьте на вопросы:

1. Are printers always connected directly to the computer?

2. How can we classify printers?

3. What is the speed of letter-quality printer operation? What about dot-matrix printers?

4. How does an ink-jet printer operate?

5. Is it high iron content that causes the ink to take the shape of a character?

Тексты по направлению

151900.62 "Конструкторско-технологическое обеспечение

машиностроительных производств"

ВАРИАНТ 1

1. Прочитайте и письменно переведите на русский язык текст:

COMPOSITE MATERIALS

1. Composite material, also called composite, is a solid material that results when two or more different substances, each with its own characteristics, are combined to create a new substance whose properties are superior to those of the original components in a specific application.

2. For example, a fibre-glass reinforced plastic combines the high strength of thin glass fibres with the ductility and chemical resistance of plastic. Nowadays composites are being used for structures such as bridges, boat-building etc. Composite materials usually consist of synthetic fibres within a matrix, a material that surrounds and is tightly bound to the fibres. The most widely used type of composite material is polymer matrix composites (PMCs). PMCs consist of fibres made of a ceramic material such as carbon or glass embedded in a plastic matrix. Usually the fibres make up about 60 per cent by volume. Composites with metal matrices or ceramic matrices are called metal matrix composites (MMCs) and ceramic matrix composites (CMCs), respectively. Although composite materials have certain advantages over conventional materials, composites also have some disadvantages.

3. For example, PMCs and other composite materials tend to be highly anisotropic – that is, their strength, stiffness, and other engineering properties are different depending on the orientation of the composite material. For example, if a PMC is fabricated so that all the fibres are lined up parallel to one another, then the PMC will be very stiff in the direction parallel to the fibres, but not stiff in the perpendicular direction. The designer, who uses composite materials in structures subjected to multidirectional forces, must take these anisotropic properties into account.

2. Прочитайте текст снова и письменно ответьте на вопросы:

1. Is a composite a solid or a liquid material?

2. How can we utilize composite materials?

3. What do composite materials usually consist of?

4. What are polymer matrix composites?

5. How is PMC fabricated?

Вариант 2

1. Прочитайте и письменно переведите на русский язык текст:

CORROSION

1. Corrosion is deterioration of useful properties in a material due to reactions with its environment. Weakening of steel due to oxidation of the iron atoms is a well-known example of electrochemical corrosion. This type of damage usually affects metallic materials, and typically produces oxide(s) and/or salt(s) of the original metal. Corrosion also includes the dissolution of ceramic materials and can refer to discolouration and weakening of polymers by the sun's ultraviolet light.

2. Some metals are more resistant to corrosion than others, either due to the fundamental nature of the electrochemical processes involved, or due to the details of how reaction products form.

3. The materials most resistant to corrosion are those for which corrosion is thermodynamically unfavourable. Corrosion products of gold or platinum tend to decompose spontaneously into pure metal that is why these elements can be found in metallic form on Earth. More common "base" metals can only be protected by more temporary means.

4. Some metals have naturally slow reaction kinetics, even though their corrosion is thermodynamically favourable. These include such metals as zinc, magnesium and cadmium. While corrosion of these metals is continuous and ongoing, it happens at an acceptably slow rate. An extreme example is graphite, which releases large amounts of energy upon oxidation but has such slow kinetics that it is effectively immune to electrochemical corrosion under normal conditions.