SWORDS AND BLADES
Exercise 1
Exercise 2
Read the text and learn the words in bold
More than a thousand years ago, the great Arab city of Damascus was not only the centre of the Middle Eastern sword trade, but was also famous for the superb quality of the swords manufactured in the city. It was said that a Damascene sword blade was so flexible that it could be bent around a man`s body and then return to its original shape without any damage. Unfortunately, nobody knows exactly how these wonderful swords were made.
Another country which has a long history of sword-making is Japan, where there are still a few craftsmen who make samurai katana swords in the traditional way. The most famous of these is Sumitani Masamine, whose skill is so highly respected that he has been given the title of "National Living Treasure" by the Japanese government.
Traditionally, the production of a katana sword was a complex process, which often involved several craftsmen; there was a smith to forge the sword into a rough shape, another smith to form and work the metal, a specialist polisher, and finally, another specialist to form the razor sharp edge.
Exercise 3
Exercise 4
Listen to the part of a radio interview with a collector of Japanese swords (track)Exercise 5
Exercise 6
VOCABULARY PRACTICE
PREVENT = to stop something
PERMIT = allow something
AVOID = not to do something
Look at these examples:
Avoid bending or flexing the PCB by holding it in a suitable stand.
A small gap should be left to allow ventilation airflow between the component and the PCB.
This layer of lacquer will prevent corrosion.
Exercise 7
Exercise 8
Read the text about eddy current inspection and decide if the statements are true or false
1 Faults in a metal cause changes in its conductivity.
2 Eddy current inspection is used most often to find rust.
3 ECI can only be used to find corrosion on the outside of a metal object.
4 ECI cannot be used to find cracks that are not visible to the naked eye.
5 ECI can help to identify different metal alloys.
Eddy current inspection checks for faults inside a metal by detecting a change in its conductivity caused by the presence of a fault. This method is especially suited for detecting corrosion. A test probe containing an AC-excited coil produces a changing magnetic field which induces eddy currents in the metal.
The amount of induced eddy current is determined by four things:
1. the conductivity of the metal, which is a function of its alloy type, grain size, degree of heat treatment and tensile strength;
2. the permeability of the metal;
3. the mass of the material;
4. the presence of any faults such as cracks or voids.
ECI is particularly suitable for:
1. identifying metals by comparison of their alloy type, degree of heat treatment and tensile strength.
2. detection of cracks or hidden faults. This is an ideal way to check aircraft wheels for cracks. These cracks close up when the stress is off the wheel and are almost impossible to detect visually, but show up with eddy current inspection.
3. detection of corrosion. The mass of sound material changes when corrosion is present, either internally or on the opposite side of a metal skin being inspected.
How to use:
1. Excite the coil with the correct frequency of AC.
2. Hold the eddy current probe against a part of the metal skin that is known to be free of corrosion or other faults and zero the meter.
3. Place the probe on the surface being inspected.
4. If there are any faults within the metal, a different amount of current will be induced and the display indicator will show the difference.
5. To inspect for corrosion around fastener holes, insert the small probe into a hole known to be free of corrosion and zero the indicator. When the probe is inserted into a hole where there is corrosion, the indicator will move off zero.
Now you can check your answers.
Exercise 9
Correct the spelling of these words
1 mashine 2 replace
3 apropriete 4 external
5 overhall 6 insbection
7 defct 8 repair
9 envirement 10 propeller
11 safety 12 controle
Check your answers here.
