Positioning and Proximity

In a number of renewable energy processes, information on the linear or rotational position of solar collector or wind turbine components is needed to control and optimize the operation of these processes. 

The operation of proximity sensors can be based on a wide range of principles, including capacitance, induction, Hall and magnetic effects variable reluctance, linear variable differential transformer (LVDT), variable resistor mechanical and electromechanical limit switches optical, photoelectric, or fiber-optic sensors laser-based distance, dimension, or thickness sensors air gap sensors ultrasonic and displacement transducers. Their detection ranges vary from micrometers to meters, and their applications include the measurement of position, displacement, proximity, or operational limits in controlling moving components of valves and dampers. Either linear or angular position can be measured  

Linear position Linear motion is typically driven by the use of lead screws, ball screws, or worm drives with ranges from less than a 25 mm to over 6 m. Linear sensors for position feedback in the lower range include LVDTs, magnetic, and optical encoders. For longer strokes, the linear feedback devices include encoders and magnetostrictive position transducers. Optical encoders are practical up to 2 m. Magnetostrictive position transducers can be used up to 20 m. 

Angular position Gearboxes are normally used to transmit rotary motion, but direct drive is also used. The motion, often driven by a 

Minimum Rupture Pressures3 as a Function of Size, Based on 70°F (21 °C) OperatingTemperature and on Standard Disk Design 3 

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Crop production can be regarded as essentially the conversion of solar radiatiort, water and soil nutrients into useful end-products. The influences of various aspects of weather and climate on potential crop production can be mtmeroits and varied. For instance, simshine and rainfall could be cortsidered as primary controls of production because of their immediate influence on the rate of crop metabolism, nutrient uptake, tiugidity, biochemical processes within the plant and crop stracture, as well as their effect on soil and air temperature. In addition there will be an effect from topography, geographical position and proximity to bodies of water. Other climatic elements such as frosts, wind and hirmidity will also have an... 

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