Solar microclimatology

It has become apparent in recent years that solar energy can be used for electric power production by several methods. Because of the diffuse nature of the solar insolation, the area involved in any central power plant design can encompass several square miles. A detailed design of these large area collection systems will require precise knowledge of the local solar insolation. Detailed information will also be needed concerning the temporal nature of the insolation and the local spatial distribution. Therefore, insolation data was collected and analyzed for a network of sensors distributed over an area of several square kilometers in Arizona. The analyses of this data yielded probability distributions of cloud size, velocity, and direction of motion which were compared with data obtained from the National Weather Service. Microclimatological analyses were also performed for suitable modeling parameters pertinent to large scale electric power plant design. Instrumentation used to collect the data is described

Multiwavelength Observations of the Hot DB Star PG 0112+104

We present a comprehensive multiwavelength analysis of the hot DB white dwarf PG 0112+104. Our analysis relies on newly-acquired FUSE observations, on medium-resolution FOS and GHRS data, on archival high-resolution GHRS observations, on optical spectrophotometry both in the blue and around Halpha, as well as on time-resolved photometry. From the optical data, we derive a self-consistent effective temperature of 31,300+-500 K, a surface gravity of log g = 7.8 +- 0.1 (M=0.52 Msun), and a hydrogen abundance of log N(H)/N(He) < -4.0. The FUSE spectra reveal the presence of CII and CIII lines that complement the previous detection of CII transitions with the GHRS. The improved carbon abundance in this hot object is log N(C)/N(He) = -6.15 +- 0.23. No photospheric features associated with other heavy elements are detected. We reconsider the role of PG 0112+104 in the definition of the blue edge of the V777 Her instability strip in light of our high-speed photometry, and contrast our results with those of previous observations carried out at the McDonald Observatory.Comment: 10 pages in emulateapj, 9 figures, accepted for publication in Ap

Qualification test results for blue-red reflecting solar covers

Recent market forces and design innovations have spurred the development of solar cell covers that significantly reduce the solar absorptance for a cell array. GaAs cells, using Ge as the substrate host material, can have a significantly higher output if the solar absorptance of the cell array is reduced. New optical coating design techniques have allowed the construction of covers that reflect the ultraviolet energy (below 350 nm) and the near infrared energy (above 900 nm) resulting in the beneficial reduction in absorptance. Recent modeling suggests three or more present output increase due to the lowered temperature with such a device. Within the last several months we have completed the testing of production samples of these new covers in a qualification series that included the usual environmental effects associated with the routine testing of solar cell covers and the combined effects of protons, electrons and solar UV as would be encountered in space. For the combined effects testing the samples were exposed to 300 sun days equivalent UV, 5 x 10(exp 14)/sq cm of 0.5 MeV protons and 10(exp 15)/sq cm of 1.0 MeV electrons. Measurements of the reflectance, transmission, emittance and other appropriate parameters were made before and after the testing. As measured by the averaged transmission over the cell operating band, the change in transmission for the samples was less than or about equal to 1 percent. The details of the testing and the results in terms of transmission, reflectance and emittance are discussed in the paper

Comparative analysis of variance of several flexible contact lens materials to gas permeability at normal atmospheric pressure relative to state of hydration

Comparative analysis of variance of several flexible contact lens materials to gas permeability at normal atmospheric pressure relative to state of hydratio

Inversion of synrift normal faults in the High Atlas Mountains, Morocco

Copyright 1997, Society for Exploration Geophysics. See also: http://segdl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=LEEDFF000016000008001171000001&idtype=cvips&gifs=Yes; http://atlas.geo.cornell.edu/morocco/publications/beauchamp1997.htmStructural inversion related to intracontinental rifting occurs when extensional rift faults reverse their sense of motion during subsequent episodes of compressional tectonics. Features generated by extension, such as half grabens, are uplifted to form positive anticlinal structures

Coherent Error Suppression in Multi-Qubit Entangling Gates

We demonstrate a simple pulse shaping technique designed to improve the fidelity of spin-dependent force operations commonly used to implement entangling gates in trapped-ion systems. This extension of the M{\o}lmer-S{\o}rensen gate can theoretically suppress the effects of certain frequency and timing errors to any desired order and is demonstrated through Walsh modulation of a two-qubit entangling gate on trapped atomic ions. The technique is applicable to any system of qubits coupled through collective harmonic oscillator modes

Effect of fatigue and hypohydration on gait characteristics during treadmill exercise in the heat while wearing firefighter thermal protective clothing.

This study compared the gait characteristics of individuals walking in heat while wearing firefighting equipment in fatigued and non-fatigued states. Nineteen subjects performed a 50-min treadmill protocol in a heated room while gait patterns were recorded using a digital video camcorder. Forty gait cycles were analyzed near the beginning (9 min) and at the end (39-49 min) of exercise. Spatio-temporal gait variables including step frequency, step length, swing time, stance time, cycle time and double-support time were determined. Gait variability was quantified by the standard deviation (SD) and coefficient of variation (CV) of each variable. Left-right symmetry was calculated using the symmetry index (SI) and symmetry angle (SA). Paired t-tests (alpha = 0.05) were performed to identify difference between the beginning and the end of the protocol for each measured variable. Spatio-temporal gait characteristics did not differ between the beginning and the end of exercise. Gait variability of the double-support time increased at the end as measured by both SD (P = 0.037) and CV (P = 0.030) but no change was observed for other variables. Left-right symmetry measured using either SI or SA did not differ between sessions. In summary, spatio-temporal gait characteristics and symmetry while wearing firefighting equipment are insensitive to physiological fatigue. Prolonged walking in heat while wearing firefighting equipment may increase gait variability and therefore the likelihood of a fall. Future studies are needed to confirm the potential relationship between fatigue and gait variability and to investigate the possible influence of individual variation

Intercomparison of ground-based and space solar flux measurements

Detailed temporal measurements of the solar flux at one location are performed. These data are then analyzed and compared to the potential of space measurements which allow one to consider the flux falling on areas of the earth. An important result of the research is that the temporal characteristics of the flux in the presence of a real atmosphere would be difficult to obtain from space and that the variations in the flux can be highly significant in regard to most solar conversion schemes. The detailed results of the research are presented. The instruments developed to separate the direct and scattered solar flux, the computer analysis methods developed, and the results of the research, presented as both graphical and tabular data, are discussed