A study of electric power generating cycles which can be used in conjunction with a low-temperature geothermal energy (sensible heat) source is presented. Investigators at Los Alamos Scientific Laboratory have proposed a steam/isobutane dual cycle capable of generating 50.7 Mw of electric power. This cycle is optimized using regenerative feed water heating to yield a power output of 52.1 Mw or an improvement of 2.8%. Other power cycle designs and working fluids are investigated. Working fluids including various freons, steam, isobutane, ammonia, SO/sub 2/, CO/sub 2/, and several low molecular weight alkanes and alkenes are considered. The power cycle designs which are investigated include single and dual Rankine cycles (some of which involve regenerative feed heating), as well as topping/bottoming Rankine cycles, and Brayton gas cycles. The investigation shows that use of a single freon-11 cycle results in a 57.7 Mw power output representing an improvement of 13.8% over the LASL proposal. This cycle represents the best performance of all the combinations investigated, although several other cycles exhibit performance superior to that of the LASL proposal. It is recommended that the freon-11 single cycle be considered on an economic basis as a replacement for the steam/isobutane cycle in the proposed …

Pressure transducers and accelerometers that make use of semiconductors strain gages or have strain gages diffused on a silicon diaphragm cannot be used with a bridge balance network if one wants to achieve thermal zero compensation. Thermal zero compensation is compensating for the change in output due to temperature only, and is typically +-1.5 percent of the full scale output for a temperature change of 100/sup 0/F. The reason for not using a balance network is the way in which the transducer is thermally compensated. There are two ways to obtain thermal zero compensation with a semiconductor transducer: either match each individual gage to each other, or trim one-half of the bridge to match the other half of the bridge. It is the latter that is easiest to do and the method the manufacturers use. The method is described.

Natural communities respond to disruption through a series of changes in plant and animal communities that are broadly predictable. The field-to-forest sere of central Long Island follows the pattern set forth earlier for the Piedmont of North Carolina and for New Jersey. The communities of herbs that occur in the years immediately after abandonment are followed by an Andropogon stage which is replaced before the 20th year by pine forest. The pine is replaced in the next 25 years by oak-pine, which in the normal Course is followed by oak-hickory. With repeated burning the oak-pine stage in various combinations of oaks and pine may be maintained indefinitely. Diversity, measured as number of species per unit land area, increased in this sere through the 3-5th years after abandonment to a maximum, dropped, and rose again in the later forest stages. Exotics were a conspicuous part of the communities of the earlier stages but their importance diminished as succession progressed and their contribution to net production was zero beyond the 20th year. The removal of exotics would probably not have changed the pattern of diversity appreciably. Net primary production increased with succession in this sere with major changes occurring as life-forms of …

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X-ray diffraction data for graphite-related and diamond-related forms of carbon.

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The phases of resonant amplitudes in pi N yields pi DELTA are studied in a modified version of SU(6)w in which amplitudes involving different relative orbital angular momenta l are uncoupled from one another. This form of SU(6)/sub W/ is equivalent to one studied recently by Melosh, in which the set of selection rules for decays is extended to allow for more types of transition than in the original version of this symmetry. The predictions are compared with a recent preliminary analysis by Herndon et al. Even the extended (''l-broken'') version of SU(6)/sub W/ is found to disagree with the present experimental solution. If this solution persists, it constitutes the strongest present evidence against such a symmetry. (auth)

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