120,824 research outputs found
Evaluation of flat-plate collector efficiency under controlled conditions in a solar simulator
The measured thermal efficiencies of 35 collectors tested with a solar simulator, along with the correlation equations used to generalize the data, are presented. The single correlation used is shown to apply to all the different types of collectors tested, including one with black paint and one cover, one with a selective surface coating and two covers, and an evacuated-tube collector. The test and correlation technique is also modified by using a shield so that collectors larger than the simulator test area can also be tested. This technique was verified experimentally for a shielded collector for which the collector shielded area was 31% of the solar simulator radiation area. A table lists all the collectors tested, the collector areas, and the experimental constants used to correlate the data for each collector
Physiological Studies of Heat Stress Acclimation During a Specific Exercise Regimen
Eleven subjects were used to determine if the exercise regimen of racquetball could be used as a heat stress acclimator. Core temperature, skin temperature, sweat production, and weight loss were recorded during a racquetball match. Skin and core temperatures were determined by using thermistors. Sweat was collected with modified stress electrodes. Weight loss was recorded by comparing nude weights at the beginning and end of a match. The results indicated that an hour of strenuous racquetball play caused a significant increase in core temperature with subsequent sweating which resulted in a significant decrease in skin temperature and weight loss. The exercise regimen of racquetball can act as a good heat stress acclimator because it produces sufficiently high levels of hyperthermia
High pressure cosmochemistry applied to major planetary interiors: Experimental studies
The infrared spectra of H2O ice VII and D2O ice VII were studied and techniques were developed for measuring adiabats of phases of NH3-H2O to 5 GPa. A mixing system for pressurized fluids was constructed in which liquid solutions of definite compositions can be prepared and loaded reliably into diamond cells in a project which seeks to determine the properties and boundaries of several high pressure phases of the H2-He-H2O-NH3-CH4 system. These data are needed to constrain theoretical models of the interiors of the major planets
High pressure cosmochemistry applied to major planetary interiors: Experimental studies
The measurement of equilibria in binary fluid-solid systems in diamond anvil cells, represents a major advance of the art of high-pressure experimentation. Vibrational spectroscopy, direct visual observations, and X-ray diffraction crystallography of materials confined in externally heated cells are the primary experimental probes being used. Adiabats in these systems are being measured in order to constrain models of heat flow in these bodies and to detect phase transitions by thermal anomalies. Other studies are directed toward interpreting high pressure reactions in these systems that are suggested by shockwave measurements, and developing methods for reaching high temperatures and high pressures of planetary interest in diamond cells. The overall objective of this project is to determine the properties of the H2-He-H2O-HN3-CH4 system and related small-molecule systems that are needed to constrain theoretical models of the interiors of the major planets
Mixed population Minority Game with generalized strategies
We present a quantitative theory, based on crowd effects, for the market
volatility in a Minority Game played by a mixed population. Below a critical
concentration of generalized strategy players, we find that the volatility in
the crowded regime remains above the random coin-toss value regardless of the
"temperature" controlling strategy use. Our theory yields good agreement with
numerical simulations.Comment: Revtex file + 3 figure
High pressure cosmochemistry applied to major planetary interiors: Experimental studies
Progress is reported in the development of the P-T-X diagram for 0 less than or = X less than or = 0.50 and in the development of techniques for measuring adiabats of phases of NH3-H2O. The partial phase diagram is presented, investigations of the compositions of ammonia ices are described, and methods for obtaining the infrared spectra of ices are discussed
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