House mechanism

Radical Anion Mechanism (Modified House Mechanism)... 

Reduction of octahydro-2(3//)-naphthalenone with metal/ammonia affords preferentially />ra ,s-octahydro-2( 1 //)-napht.halenonc, i.e., the thermodynamically more stable reduction product (House mechanism, p 3967)29. The reaction mixture is worked up by reoxidation with chromic acid and chromatography to separate higher molecular weight byproducts. 

Application of a steady-state approximation to the concentration of the intermediate acetophenone ketyl provided a rate equation that predicted first order dependence on [Sml2], [acetophenone], and [proton donor] for a traditional House mechanism for the reduction of a ketone (House, 1972). The presence of methanol, ethanol, 2,2,2-trifluoroethanol, and phenol fit this mechanism and in fact a plot of pKa vs. A obs provided a linear correlation coefficient of 0.996 consistent with the acidity of the proton donor dictating the rate of reduction. Since... 

J. E. House, Fundamentals of Quantum Mechanic.s Academic Press, San Diego (1998). P. W. Atkins, R. S. Friedman, Molecular Quantum Mechanic.s Oxford, Oxford (1997). 

The housing physically holds the valve pieces together by means of a mechanical lock (crimp) and fits into the pedestal of the mounting cup. It is made from any of a number of common thermoplastics and contains the metering orifices for both the Hquid and vapor phases of the effluent. Many... 

The output signal from positive-displacement meters may be mechanical, where the motion is transmitted by an output shaft through a housing seal, or it may be magnetically or inductively coupled. 

Materials and Reactions. Candle systems vary in mechanical design and shape but contain the same genetic components (Fig. 1). The candle mass contains a cone of material high in iron which initiates reaction of the soHd chlorate composite. Reaction of the cone material is started by a flash powder train fired by a spring-actuated hammer against a primer. An electrically heated wire has also been used. The candle is wrapped in insulation and held in an outer housing that is equipped with a gas exit port and rehef valve. Other elements of the assembly include gas-conditioning filters and chemicals and supports for vibration and shock resistance (4). 

Marketing. Most of the cocoa beans and products imported into the United States are done so by New York and London trade houses. The New York Sugar, Coffee, and Cocoa Exchange provides a mechanism by which both chocolate manufacturers and trade houses can hedge their cocoa bean transactions. Additional information on the functions of the New York Cocoa Exchange is available (3). 

Using other criteria, compressors are classified as open, semiher-metic accessible), or hermetic. Open type is characterized by shaft extension out of compressor where it is coupled to the driving motor. When the electric motor is in the same housing with the compressor mechanism, it could be either hermetic or accessible (semihermetic). Hermetic compressors have welded enclosures, not designed to be repaired, and are generally manufac tured for smaller capacities (sel-... 

Description An agitated dryer is defined as one on which the housing enclosing the process is stationaiy while solids movement is accomplished by an internal mechanical agitator. Many forms are in use, including batch and continuous versions. 

In any event, the users of the mixer can issue a mechanical specification aud determine the speed, diameter of an impeller, aud power with in-house expertise. Or they may issue a processes specification which describes the engineering purpose of the mixing operation and the vendor will supply a description of the mixer process performance as well as prepare a mechanical design. 

UF and MF use energy to depolarize membranes so as to increase flux. As is shown in Fig. 22-55, membranes and mechanical equipment are traded off to achieve an overall economic minimum. Three things can drive a design toward the use of more membranes and less mechanical equipment cheaper membranes, veiy high flux, and veiy low flux. The availability of lower-cost membranes is easiest to understand. In the five years ending in 1995, the cost of both membrane area and membrane housings was driven down by competition. 

We put a contact thermometer on the bearing housing. The thermometer indicated 152° F. During all these years, this chief mechanic s hands had seen a lot of temperature, abrasion, and abuse. His hands and touch were much more re - w ant to heat than mine, or the PM inspector s hands. 

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