The danger of Air and Bubbles.

YASER RASHWAN

Mechanical Engineer

Reference:

Garner, D. (2010, April 15) The danger of Air and Bubbles. From http://www.chemie.de/articles/e/103550/

Summary:

One of the most serious problems faced by the hydraulic and lubrication oil system is the air and bubbles. The air usually enters from the suction of the pumps; it causes foaming inside the system, which indicates the wrong reading of the level. Another problem is the cavitations, which happens in the pumps. It happens when the pressure of the liquid is less than the gas inside it. That leads to mechanical failure, which causes the damage to the equipment. Therefore should watch the entrance of the pump and be sure it is safe; also, it should be changed if necessary.

Reaction:

This is a common problem in the most industries; therefore, every company is trying to reduce this problem as much as possible. For example, they install different types of sensors to keep the equipment safe. And for the foaming, they put antifoam, depending on the kind of liquid, in the system. Cavitations and foaming lead to stopping the whole plant; because of this, operators in the plant should take care to avoid these problems, by taking readings, watching the levels, recognizing any abnormal sounds. The cavitations also cause serious problems like fire and explosion.

RRJ1 (Introduction to welding)

Reference:

Kristoff , S (2009, Oct 13). Introduction to welding. From http://manufacture-engineering.suite101.com/article.cfm/introduction_to_welding

Summary:

Welding is a process that is used to connect two pieces of metal together, by heating them until they melt. However the gaps are filled with another material like welding rod or wire. There are many types of welding such as Gas Welding by mixing oxygen and acetylene; it is a common type of welding; also it is used for brazing, cutting and heating metal. Another type of welding is called Arc welding; it is working by electrical current. Another type is Spot welding to join small sheets of metal by electrical current. Each of these types of welding has different uses, especially for industry.

Reaction:

This article is un introduction of welding because there are many types of welding for different uses. The welding is like Art; it is very exiting and you have to be accurate. Also you have to take care if you want to be a wilder, because you are dealing with a high temperature and high electrical currents. You should wear a full PPE (Personal Protected Equipments) to do any type of welding. There is a welding underwater which is the most dangerous work in the world.

Vocabulary:

Fabrication- to invent or produce (esp. a story that isn't true) in order to deceive

Combination- together

Brazing-mixing

Invariable-never changing

Appropriate-correct and right thing to do