03.08.2009

The Tip Speed Ratio is of important relevance in the design of wind turbine generators. If the rotor of the wind turbine turns too slowly, most of the wind will pass undisturbed through the gap between the rotor blades. Alternatively if the rotor turns too quickly, the blurring blades will appear like a solid wall to the wind. Therefore, wind turbines are designed with optimal tip speed ratios to extract as much power out of the wind as possible. When a rotor blade passes through the air it leaves turbulence in its wake. If the next blade on the spinning rotor arrives at this point while the air is still turbulent, it will not be able to extract power efficiently from the wind. However if the rotor span a little more slowly the air hitting each turbine blade would no longer be turbulent. Therefore the tip speed ratio is chosen so that the blades do not pass through turbulent air.

Based on harnessing the ebb and flow of the tide as it moves a huge amount of water twice each day to turn a turbine

The Thomas-Stieber model was developed to estimate net/gross (sand fraction) and sand porosity in sand/shale sequences with bed thickness below log resolution (thin-bed analysis)

In a petrophysical sense, thin beds can be defined as beds that are thinner than the resolution of the logging tools used to characterize them. This implies that the direct log values do not represent the true bed or layer properties, but rather an average of multiple beds. In the typical case of sand interbedded with shale, the logs will reflect an average of sand and shale properties. Direct interpretation of the log readings will therefore result in a significant underestimation of reservoir quality. Once such a scenario has been recognized, an interpretation methodology can be chosen that takes the inadequate log resolution into account. One such method is the Thomas-Stieber method

Bacteria involved in biodegradation

Ten Petroleum Company Ltd. markets and supplies fuel through full service filling stations with no extra charge. The company operates a few dozen self-service filling stations across Israel. The company’s annual turnover stands at NIS 1 billion. In 1994, the company was acquired by businessman Eliezer Fishman. The company is owned by Eliezer Fishman (85%) and Excellence (15%).