Siemens unit

SE, abbrev. (Sieinens-Einheit) Siemens unit. Sebacinsaure, Sebazinsaure, /. sebacic acid, secernieren, v.t. secrete, sechs, a. six. 

Ostwald, recalculated so as to give the equivalent conductances in ohm cm. units, instead of reciprocal Siemens units they show that the equation given above is approximately true, and hence it may be employed to determine the basicity of an acid. The method fails when applied to very weak acids whose salts are considerably hydrolyzed in solution. The results quoted in Table XX are perhaps exceptionally favorable, for the agreement with equation (27) is not always as good as these figures would imply. The Ostwald rule is, nevertheless, an expression of the facts already discussed, viz., that substances of the same valence type have approximately the same conductance ratios at equivalent concentrations and that the values diminish with increasing valence of one or both ions. The rule has been extended by Bredig (1894) to include electrolytes of various types. 

The units of concentration and conductivity used by Kohlrausch varied in his different publications and it was not until 1898 (Kohlrausch, L. Holborn, and H. Diesselhorst, Ann, Phys.y 1898, Ixiv, 417 Ges, Abhl., ii, 737) that the ohm was adopted as the resistance unit. Ostwald used the molecular conductivity kjm y where m is the molecular concentration of the electrolyte, and Siemens units (seep. 669). 

The hardware safety integrity of these PLCs has been certified to category 4 of EN 954-1 and, in the case of the Siemens units, to SIL 3 of lEC 61508. 

Siemens AG has been involved in R D on PFFCs, and Vickers Shipbuilding Engineering Ltd. (United Kingdom) is evaluating PFFCs from Ballard Power Systems for power generation. A 35-ceU stack was successfully tested for more than 300 h. Plans are under way to test a 20-kW PEFC. 

PV systems consist of arrays of cells that ate interconnected in panels or modules to increase total power output. Often the systems include sun-tracking equipment, as well as power-conditioning equipment to convert dc to ac. The systems can range in size from a simple one-panel, fixed-orientation unit to a vast field of modules that accurately track the movement of the sun. Electric utiUties in Europe, Japan, and the United States have hosted several experimental PV power plants. The largest to date was a 5.5-MW plant at Carrisa Plains, California, built by Siemens Solar Industries (formerly ARCO Solar). 

The plural form of a symbol is the same as the singular. Plurals of unit names are formed by adding an "s", except in henries hertz, lux, and siemens are not changed. 

Figure 6.24(b) Thyristor cubicles for high-power static converter units (Courtesy Siemens)... 

The phenomenon of transmitting electrons through a body (an electric current). Usually associated with the measurement of electrical conductivity through water and measured in micro Siemens per centimeter (p,S/cm) or micromho per centimeter ( xmho/cm). 1 p,S/cm = 1 xmho/cm. The mho is equivalent to a reciprocal ohm (the unit of resistivity). 

Oxford Siemens Molecular Imaging Laboratory, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom... 

Siemens Power Generation is a partner with ConocoPhillips and Air Products and Chemicals, Inc., (APCI) to develop large-scale fuel cell systems based upon their gas turbine and SECA SOFC technologies. The design will use an ion transport membrane (ITM) oxygen air separation unit (ASU) from APCI with improved system efficiency. 

Companies such as United Technologies Corp. (UTC), Ballard Energy Systems, Plug Power, M-C Power, AlliedSignal, and Siemens-Westing-house have been developing fuel cell products for the commercial market and may be impacted by this trend. 

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