Mechanical Engineering & Documents

Reliance Industries, headed by billionaire Mukesh Ambani might be gearing up to enter the telecom sector. After the cancellation of 122 licenses by the supreme court earlier this year in February, the government is all set for the auction of the vacant 2G spectrum and the application process for the same starts from September 28. Once the application process gets over, the auction of licenses must begin by November 12. Government has plans to auction airwaves frequencies in 1800 Mhz (GSM) band and 800 Mhz (CDMA) band which are being used for the mobile telephony services.

Reciprocating and rotary pumps are two types of positive displacement pumps. Essentially, positive displacement pumps enable the movement of fluid from one side of the pump to another using a rotational motion. They are also called constant   flow  machines because, theoretically speaking, they produce the same flow regardless of the discharge pressure. Reciprocating and rotary pumps refer to the mechanism used in each type of pump that moves the fluid. In both types of pumps, there is an expanding cavity on the suction side and a decreasing cavity on the discharge side. The volume of liqui is constant in both cases.

Every type of fluid possesses differing amounts of resistances against deformation. The measure of that resistance is called viscosity. Viscosity expresses the fluid’s resistance against either tensional stress, or shear stress. In common terms, viscosity is the thinness or thickness of the fluid. A great example of this, is the difference in the viscosities of water and honey. Water is considered as ‘thin’, thus, the viscosity is lower. On the other hand, honey is significantly ‘thick’, and is a fluid with a higher viscosity. Viscosity can also be considered as a measure of the friction of fluids, as it also describes the internal resistance of the flow of fluid. There are two ways to report or measure a fluid’s viscosity. It can either be expressed as dynamic viscosity, or kinematic viscosity. Many are confused between these two types of viscosity expression, and some even consider them to be one and the same. In reality, they are two significantly different expressions.

R744 is a nomenclature used in industry to indicate carbon dioxide, a gas used predominantly as a liquid coolant in refrigeration systems, commercial and industrial. The use of R744 as a refrigerant has been completely re-evaluated in recent decades because of environmental issues such as global warming and the toxicity of some components. The advantages of the R744 are mainly in its low environmental impact: R744 it is not toxic, not flammable and contributes to reduced global warming. Although not yet identified a replacement for the standard use of HFCs in refrigeration, the R744 is rapidly spreading in many countries, where some regulations encourage the use. A major difficulty in using the R744 is given by the high pressure (up to 130 bar) and are therefore required components and systems capable of operating at high pressure systems, with high resistance. Teklab , an italian manufacturer, is one of those companies that offer systems that can operate at high pres