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five cell array capable of 1 watt output in bright sunlight is now possible. Radiation studies show that the decrease of efficiency can be predicted from laboratory measurements of lifetime.
G r a c e , W. R., " I n v e s t i g a t i o n of T h i n S h e e t s of H i g h Q u a l i t y , S i n g l e - C r y s t a l S i l i c o n . " U. S. A r m y S i g n a l R e s e a r c h & D e v e l o p m e n t L a b o r a t o r y , R e p o r t N o . 3, A R P A O r d e r N o . 8 0 - 5 9 , S e p t . 10, 1 9 6 0 . 3 1 p. Illus.
E s e o f f e r y , C. A. a n d L u f t , W e r n e r , " S i l i c o n P h o t o v o l t a i c Cells a n d t h e U t i l i z a t i o n of S o l a r E n e r g y . " I n t e r n a t i o n a l R e c t i f i e r C o r p . , J u n e , 1 9 6 0 . 1 6 p. Illus.
The purpose of this contract is to investigate and determine the feasibility of a concept advanced by Dr. W. Shockley of floating a thin layer or film of molten silicon upon a liquid metal surface, preferably lead, and pulling the silicon horizontally through a temper-~ture gradient to obtain a single crystal in the form of thin sheet. The objective is to develop a method for the continuous production of thin sheets of high-quality, single-crystal silicon of less than 1 mm thickness and of appreciably greater dimensions than currently available.
Silicon photovoltaic cells are heing widely used in munerous applications, both celestial and terrestrial, for the direct conversion of solar radiation into electric power. The possibility of relieving the world energy problem by the photovoltaic process is discussed. Present day silicon solar cells have conversion efficiencies of 12 per cent or more, and the preparation, operating principles, and characteristics of silicon solar cells are presented. The control of cell temperature in space vehicles is discussed in terms of the absorptance and emittance of radiation by the silicon cell surface, and measured values of these parameters are shown for uncovered cells and for cells provided with glass or with silicon oxide films.
W y s o c k i , J o s e p h J., a n d R a p p a p o r t , P a u l , " E f f e c t of T e m p e r a t u r e on P h o t o v o l t a i c S o l a r E n e r g y C o n v e r s i o n , " Journal of Applied Physics, 31 (3): 5 7 1 - 5 7 8 , M a r c h 1960. Illus. Photovoltaic solar energy conversion is investigated theoretically over a temperature range of 0-400 C using semiconductor nmterials with band gaps varying from 0.7 to 2.4 ev. Three cases are considered. In Case 1, the junction current is tile ideal current. In Case 11, the junction current is the ideal plus a recombination current; and in Case 111, a recombination current. The best conversion performance is obtained for the ideal current; the worst, for the recombination current. The maximum conversion efficiency occurs in materials with higher hand gap as the temperature {s increased. GaAs is close to the optimum material for temperatures below 200 C. Experimental measurements are presented on St, GaAs, and CdS cells. The measurements on Si and GaAs agree with theoretical expectations as far as the gross behavior is concerned. The CdS cell behaves anomalously as if it were made from a material with band gap of 1.1 ev.
G o r d o n , G. D . , " M e a s u r e m e n t of R a t i o of A b s o r p t i v i t y of S u n l i g h t to T h e r m a l E n f i s s i v i t y . " The Review of Scientific Instraments, 31 (11) : 1204-1207, N o v . 1960. Illus. Direct measurements of the ratio of the surface absorptivity of sunlight to the therlnal emissivity have been made, and the apparatus is described. A thin plate to be measured is suspended in a w~cuum, surrounded by walls cooled by liquid nitrogen, and illuminated by an arc light, which simulates solar radiation. The desired ratio is determined from the equilibrium temperature, which ranged from 0 to 250 C for the samples measured. Possible errors in the procedure have been analyzed theoretically, and corrections introduced where necessary. Intensity fluctuations ill the present light som'ce have limited the accuracy to 10%, hut this is not a fundamental limitation in the method. Values of the thermal emissivity are ,also obtained from the rate of change of sample temperature.
XI--Radiation ~lechanics: Insolation, Spectroscopy, Spectral Distribution F r i t z , S i g m u n d , " S o l a r R a d i a t i o n M e a s u r e m e n t s in t h e A r c t i c O c e a n . " Geophysical Research Paper No. 63, Scientific Studies at Fletcher's Ice Island, T-3, 1952-1955, 1 l : 6 - 1 0 , D e c . 1959. Illus.
K r a c h e r , R i c h a r d W . , "Advent." P r e s e n t e d a t A R S Space Power Systems Conference, Santa Monica, Calif., S e p t . 2 7 - 3 0 , 1 9 6 0 . 3 p. Illus. ( 1 3 4 3 - 6 0 )
For several vears the U. S. Air Force Cambridge Research Center has ma~le various measurements on ice islands in the Arctic Ocean. Among the measurements was the amount of solar energy received on a horizontal surface from sun and sky, and this report summarizes the data taken on Fletcher's Ice Island, T-3, during the year 1953. During the period March through October, the solar energy is measurable. In 1953 at that time T-3 was located near 86°N and 90°W, which is in the Arctic Ocean north of Hudson Bay, Canada.
The vehicle will be positioned so that its antenna will be continually oriented toward the earth by means of the attitude control system. The electrical power for the vehicle will be drawn from the sun and converted to electricity by silicon photovoltaic cells. The tens of thousands of cells required will be distributed over one side of two p,~ddles deployed on each side of the vehicle.
S t e a r n s , F o r e s t W., a n d C a r l s o n , C h a r l e s A., " C o r r e l a tions between Soil-Moisture Depletion, Solar Radia t i o n , a n d o t h e r E n v i r o n m e n t a l F a c t o r s , " Journal of Geophysical Research, 65 (11): 3 7 2 7 - 3 7 3 2 , N o v . 1960.
S p i t z e r , C. F., " S o l a r Cell M e a s u r e m e n t S t a n d a r d i z a tion." Lockheed Aircraft Corp., Missiles & Space D i v . , S u n n y v a l e , Calif. L M S D - 2 8 8 1 8 4 , F e b . 29, 1 9 6 0 . 8 4 p. Illus. This report on solar cell standards and measurements covers the preparation of standard solar cells, methods for measuring the direct solar radiation intensity, the latitude of the observing location, and atmospheric conditions necessary to accurate measurement. Calibration and maintenance of standard solar cells are also included. Laboratory light source and instrumentation of cell measurements are discussed. Definitions of the various terminologies and a literature survey for 1949 to the present is included for the convenience of the reader.
To extend the usefulness of a soil-moisture prediction method, solar radiation, temperature, and other environmental factors were studied in relation to moisture loss in the surface 12 inches of soil. D a t a were obtained in an upland meadow on loessial soil near Vicksburg, Mississippi. Comparisons were made only for drying periods, and only when soil moisture was in the wetter half of its range. Highest correlations of single factors with moisture loss were obtained with soil temperature and evaporation-pan data 145
G r a c e , W. R., " I n v e s t i g a t i o n of T h i n S h e e t s of H i g h Q u a l i t y , S i n g l e - C r y s t a l S i l i c o n . " U. S. A r m y S i g n a l R e s e a r c h & D e v e l o p m e n t L a b o r a t o r y , R e p o r t N o . 3, A R P A O r d e r N o . 8 0 - 5 9 , S e p t . 10, 1 9 6 0 . 3 1 p. Illus.
E s e o f f e r y , C. A. a n d L u f t , W e r n e r , " S i l i c o n P h o t o v o l t a i c Cells a n d t h e U t i l i z a t i o n of S o l a r E n e r g y . " I n t e r n a t i o n a l R e c t i f i e r C o r p . , J u n e , 1 9 6 0 . 1 6 p. Illus.
The purpose of this contract is to investigate and determine the feasibility of a concept advanced by Dr. W. Shockley of floating a thin layer or film of molten silicon upon a liquid metal surface, preferably lead, and pulling the silicon horizontally through a temper-~ture gradient to obtain a single crystal in the form of thin sheet. The objective is to develop a method for the continuous production of thin sheets of high-quality, single-crystal silicon of less than 1 mm thickness and of appreciably greater dimensions than currently available.
Silicon photovoltaic cells are heing widely used in munerous applications, both celestial and terrestrial, for the direct conversion of solar radiation into electric power. The possibility of relieving the world energy problem by the photovoltaic process is discussed. Present day silicon solar cells have conversion efficiencies of 12 per cent or more, and the preparation, operating principles, and characteristics of silicon solar cells are presented. The control of cell temperature in space vehicles is discussed in terms of the absorptance and emittance of radiation by the silicon cell surface, and measured values of these parameters are shown for uncovered cells and for cells provided with glass or with silicon oxide films.
W y s o c k i , J o s e p h J., a n d R a p p a p o r t , P a u l , " E f f e c t of T e m p e r a t u r e on P h o t o v o l t a i c S o l a r E n e r g y C o n v e r s i o n , " Journal of Applied Physics, 31 (3): 5 7 1 - 5 7 8 , M a r c h 1960. Illus. Photovoltaic solar energy conversion is investigated theoretically over a temperature range of 0-400 C using semiconductor nmterials with band gaps varying from 0.7 to 2.4 ev. Three cases are considered. In Case 1, the junction current is tile ideal current. In Case 11, the junction current is the ideal plus a recombination current; and in Case 111, a recombination current. The best conversion performance is obtained for the ideal current; the worst, for the recombination current. The maximum conversion efficiency occurs in materials with higher hand gap as the temperature {s increased. GaAs is close to the optimum material for temperatures below 200 C. Experimental measurements are presented on St, GaAs, and CdS cells. The measurements on Si and GaAs agree with theoretical expectations as far as the gross behavior is concerned. The CdS cell behaves anomalously as if it were made from a material with band gap of 1.1 ev.
G o r d o n , G. D . , " M e a s u r e m e n t of R a t i o of A b s o r p t i v i t y of S u n l i g h t to T h e r m a l E n f i s s i v i t y . " The Review of Scientific Instraments, 31 (11) : 1204-1207, N o v . 1960. Illus. Direct measurements of the ratio of the surface absorptivity of sunlight to the therlnal emissivity have been made, and the apparatus is described. A thin plate to be measured is suspended in a w~cuum, surrounded by walls cooled by liquid nitrogen, and illuminated by an arc light, which simulates solar radiation. The desired ratio is determined from the equilibrium temperature, which ranged from 0 to 250 C for the samples measured. Possible errors in the procedure have been analyzed theoretically, and corrections introduced where necessary. Intensity fluctuations ill the present light som'ce have limited the accuracy to 10%, hut this is not a fundamental limitation in the method. Values of the thermal emissivity are ,also obtained from the rate of change of sample temperature.
XI--Radiation ~lechanics: Insolation, Spectroscopy, Spectral Distribution F r i t z , S i g m u n d , " S o l a r R a d i a t i o n M e a s u r e m e n t s in t h e A r c t i c O c e a n . " Geophysical Research Paper No. 63, Scientific Studies at Fletcher's Ice Island, T-3, 1952-1955, 1 l : 6 - 1 0 , D e c . 1959. Illus.
K r a c h e r , R i c h a r d W . , "Advent." P r e s e n t e d a t A R S Space Power Systems Conference, Santa Monica, Calif., S e p t . 2 7 - 3 0 , 1 9 6 0 . 3 p. Illus. ( 1 3 4 3 - 6 0 )
For several vears the U. S. Air Force Cambridge Research Center has ma~le various measurements on ice islands in the Arctic Ocean. Among the measurements was the amount of solar energy received on a horizontal surface from sun and sky, and this report summarizes the data taken on Fletcher's Ice Island, T-3, during the year 1953. During the period March through October, the solar energy is measurable. In 1953 at that time T-3 was located near 86°N and 90°W, which is in the Arctic Ocean north of Hudson Bay, Canada.
The vehicle will be positioned so that its antenna will be continually oriented toward the earth by means of the attitude control system. The electrical power for the vehicle will be drawn from the sun and converted to electricity by silicon photovoltaic cells. The tens of thousands of cells required will be distributed over one side of two p,~ddles deployed on each side of the vehicle.
S t e a r n s , F o r e s t W., a n d C a r l s o n , C h a r l e s A., " C o r r e l a tions between Soil-Moisture Depletion, Solar Radia t i o n , a n d o t h e r E n v i r o n m e n t a l F a c t o r s , " Journal of Geophysical Research, 65 (11): 3 7 2 7 - 3 7 3 2 , N o v . 1960.
S p i t z e r , C. F., " S o l a r Cell M e a s u r e m e n t S t a n d a r d i z a tion." Lockheed Aircraft Corp., Missiles & Space D i v . , S u n n y v a l e , Calif. L M S D - 2 8 8 1 8 4 , F e b . 29, 1 9 6 0 . 8 4 p. Illus. This report on solar cell standards and measurements covers the preparation of standard solar cells, methods for measuring the direct solar radiation intensity, the latitude of the observing location, and atmospheric conditions necessary to accurate measurement. Calibration and maintenance of standard solar cells are also included. Laboratory light source and instrumentation of cell measurements are discussed. Definitions of the various terminologies and a literature survey for 1949 to the present is included for the convenience of the reader.
To extend the usefulness of a soil-moisture prediction method, solar radiation, temperature, and other environmental factors were studied in relation to moisture loss in the surface 12 inches of soil. D a t a were obtained in an upland meadow on loessial soil near Vicksburg, Mississippi. Comparisons were made only for drying periods, and only when soil moisture was in the wetter half of its range. Highest correlations of single factors with moisture loss were obtained with soil temperature and evaporation-pan data 145