Name : Achmad JaelaniNIM : 21060114130099Class : BGroup: 1

CHAPTER 10

2D.In pairs, do an environmental audit for the following applications and materials. Use the words and phrases in the box.ApplicationMaterials

1. Electrical wires in vehicles2. External walls in housesCopper and aluminiumBricks and softwood

Answer:

Environmental Audit for Electrical wires in vehicles

Pre-UseIt takes more energy to produce aluminium than to produce copper, if its derived from ore. However it takes less energy to transport aluminium, because its lighter.

In-UseAluminium is better than copper because its lighter, so logically the vehicle will consume less fuel.

Post-UseBoth Aluminium and copper can be recycled. But it will more easy to recycle aluminium because its lighter.

Environmental Audit for External walls in houses

Pre-UseIt takes a lot of energy to produces bricks because they have to be fired in a kiln. And bricks are heavy to transport. Softwood are more lighter and takes less energy to handle it.

In-UseWood is better insulator than bricks which is an advantage, as the house should take less energy to heat. In theory, softwood could last as long as bricks, if its properly maintained. But in practice, that will often not be the case. So, construction energy could sometimes be higher for softwood, as houses need to be rebuilt more often.

Post-UseIts possible to recover both bricks and softwood for re-use, but neither is very easy to recycle.

4What do you know about braking systems? In pairs, discuss the following questions.

aGenerally speaking, what do breaks do and how do they work?

Answer:Brakes are designed to slow down vehicles or moving parts. Often they work trough friction, by applying pressure to pads which are pressed against the sides of a disc, the inside of a drum, or directly against a wheel rim. Alternatives include system that use electromagnetic force, system that exploit the braking effect of engines or flywheels (via clutch and gearboxes), aerodynamic braking system (on aircraft) and reverse thrusters on jet engines. Brake discs are often made of ferrous metal or sometime ceramic materials.

b.What kinds of materials are used in brake pads and brake discs in different vehicles?

Answer:a. Compounds of advanced materials in carb. Ferrous metals in trainc. Rubber in bicycled. Ceramics in performance cars

5a.Read the article on braking systems. In the title of the article, what do the colors green and red refer to?

Answer:Green refers to ecological issues, and red refers to heat. Hot topic is a current important topic

b.In pairs, answer the following questions.1. why do most braking systems waste energy?2. what are regenerative braking systems, and how do they save energy?3. what characteristics are required of materials used for the brakes on racing cars?4. what is meant by heat soak, and why is it a problem in racing cars?

Answer:1. Because they use friction, which wastes energy as heat.2. They recover heat and use it to power the car.3. The ability to generate high levels of friction, and to resist the effects of friction and consequent heat.4. Heat from the engine being absorbed by the chassis, which can damage sensitive parts such as electronic components and plastic parts.

c.Match the materials from the text (1-7) to the descriptions (a-g).1. compoundsA. materials that are not metal

2. exoticB. iron and steel

3. ferrousC. combinations of materials

4. ceramicsD. mixture of metals

5. alloyE. plastic materials

6. non-metallicF. minerals transformed by heat

7. polymersG. rare or complex

Answer1. compoundsC. combinations of materials

2. exoticG. rare or complex

3. ferrousB. iron and steel

4. ceramicsF. minerals transformed by heat

5. alloyD. mixture of metals

6. non-metallicA. materials that are not metal

7. polymersE. plastic materials

d.In pairs take turn to describe an object using the words from Exercise 5C and the phrases in the box. Ask your partner to guess what it is.Comprise Consist of Made from made of made out of

Answer:1. Compounds consist of combinations of materials2. Exotic comprise rare or complex3. Ferrous made of iron and steel4. Ceramics made out of minerals transformed by heat5. Alloy consist of mixture of metals6. Non-Metallic consist of materials that are not metal7. Polymers made from plastic materials

6a.You are going to give talk on composites technology at a contruction materials trade fair. In part of the talk, you focus on reinforced coontrete as a well-known example of a composite material. Prepare your talk using words and phases from this section and the following notes.

Reinforced ConcreteConcrete is a mixture of coarse (stone or brick chips) and fine 9generally sand or crushed stone) agregates wih apaste of binder material (usually cement) and water. When cement is mixed with a small amout of water, it hydrates to from microscopic apaque crystal lattecies encapsulting and locking the aggregate into a rigid structure.The reinforcement in a reinforced concrete structure, such as a steel bar, has to undergo the same strain or deformation as the surrounding concrete in order to prevent dicontinuity composite action requires transfer of load between the concrete and steel.

c.Margit, a sales engineer, is describing a high-voltage cable. Before you listen, label the cross-section with the part.

Answer:1. Outer jacket (C)2. Water proof membrane (B)3. Armored Protection (D)4. Insulation (A)5. Conductor (E)

e.Match the parts of the cable (a-e) in Exercise 6c to the following categories if materials (1-5). You will need to use some parts more than once.

1. non-metallic a b c2. metallic d e3. ferrous metal d4. non-ferrous metal e5. polymer-base a b c

7Imagine you are presenting a product or appliance you know well to a potential client. Describe the categories of material used to make the different parts.

A tire is a ring-shaped vehicle component that covers the wheel rim to protect it and enable better vehicle performance. The materials of modern pneumatic tires can be divided into two groups, the cords that make up the ply and the elastomer which encases them. The cords, which form the ply and bead and provide the tensile strength necessary to contain the inflation pressure, can be composed of steel. Natural fibers such as cotton of silk, or synthetic fibers. And the Elastomer, which forms the tread and encases the cards to protect them from abrasion and hold them in place, can be composed of various mixtures of synthetic rubber, natural rubber, and other chemical compound. The production starts with bulk raw materials such as rubber, carbon black, and chemicals and produces numerous specialized components that are assembled and cured.