Cadmium-sulfide solar cells in a deployable array composed of rigid frames.
Si and Cd solar cell arrays compared using rigid frame Si solar cell concept
SOLAR CELL↗
SEARCH · Engineering Papers
Results for “cell structure”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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The formation and degradation of Ti-Ag and Ti-Pd-Ag solar cell contacts
Ti-Ag and Ti-Pd-Ag solar cell contacts structure and degradation dependence on high temperature and humidity environmental exposure
Becker, W. H.↗
Dynamic response analysis of geometrically non-linear structures subjected to high impact.
Description of an efficient digital computer method for the determination of the propagation of elastic stresses and deformations in certain geometrically nonlinear structures subjected to high impact loading. The finite-element matrix displacement approach utilizing curved quadrilateral shell elements in conjunction with a nodewise predictor-corrector method employing Runge-Kutta extrapolation techniques has been adopted for the present solution. The related computer program written in FORTRAN V for the UNIVAC 1108 computer has proved to be effective for the solution of a range of practical problems including rectangular and cylindrical panels. Numerical results are presented for a relevant structure, the cell container, and the negative electrode of an impact-resistant battery subjected to high impact, simulating its free landing on a planetary surface.
Gupta, K. K.↗
Apparatus for measuring static coefficient of friction under compressive loads
Device includes load cell attached to rigid structure. Crosshead directly beneath cell is connected to constant-speed electrical motor. Crossarm supported by crosshead serves as platform on which bodies are tested. Test data are recorded on X-Y recorder which is connected to load cell and motor.
Haehner, C. L.↗
Recrystallization as a controlling process in the wear of some f.c.c. metals
Detailed examination of copper specimens after sliding against 440 C steel in liquid methane at speeds up to 25 m/s and loads of up to 2 kg showed the metal comprising the wear surface to possess a fine cell recrystallized structure. Wear proceeded by the plastic shearing of metal in this near surface region without the occurrence of visible metal transfer. A dynamic balance between the intense shear process at the surface and the nucleation of recrystallized grains was proposed to account for the behavior of the metal at the wear surface. Sliding wear experiments were also conducted on Ag, Cu-10% Al, Cu-10% Sn, Ni and Al. It was found that low wear and the absence of heavy metal transfer were associated with those metals observed to undergo recrystallization nucleation without prior recovery.
Bill, R. C.↗
Performance degradation mechanisms and modes in terrestrial photovoltaic arrays and technology for their diagnosis
Accelerated life-prediction test methodologies have been developed for the validation of a 20-year service life for low-cost photovoltaic arrays. Array failure modes, relevant materials property changes, and primary degradation mechanisms are discussed as a prerequisite to identifying suitable measurement techniques and instruments. Measurements must provide sufficient confidence to permit selection among alternative designs and materials and to stimulate widespread deployment of such arrays. Furthermore, the diversity of candidate materials and designs, and the variety of potential environmental stress combinations, degradation mechanisms and failure modes require that combinations of measurement techniques be identified which are suitable for the characterization of various encapsulation system-cell structure-environment combinations.
Noel, G. T.↗
A quinone-assisted photoformation of energy-rich chemical bonds
In a study of biochemical means of solar energy conversion, ADP and inorganic phosphates were converted to ATP by white light in the nonaqueous solvent dimethylformamide in the presence of tetrachloro-p-quinone or ubiquinone. Conversion of ADP to ATP has been accomplished in aqueous suspension by the use of cell-like structures aggregated from poly(aspartic acid, glutamic acid, tyrosine). This is believed to occur through the formation of dopaquinone in the peptide structure during illumination. The way in which the quantitative yield of ATP has been influenced by pH and by added substances, such as FeCl2, was studied.
Fox, S. W.↗
How many theories for the origin of /proto/life
The sequence of primordial chemical events leading to contemporary metabolism is considered, taking into account primordial reactants, amino acids, proteinoid, protocells, ATP, polynucleotides, and protein. The right kind of matter, thermal copolyamino acids, can organize itself into cell-like structures, in the absence of discrete lipid, when triggered to do so by water. Another unpredicted result of examination of the microsystems formed was the step-by-step realization that the component processes of a primitive form of replication were latent in the proteinoid microsystems. At the present time, four modes of primitive replication of proteinoid microsystems have been identified, plus one that has the appearance of protosexual reproduction. Two main conceptual pathways have received attention. One is the proteinoid theory, derived from experiments. The other is the DNA-first theory, for which attempts at conceptual construction and experimental support continue to be sought.
Fox, S. W.↗
A quantitative method for photovoltaic encapsulation system optimization
It is pointed out that the design of encapsulation systems for flat plate photovoltaic modules requires the fulfillment of conflicting design requirements. An investigation was conducted with the objective to find an approach which will make it possible to determine a system with optimum characteristics. The results of the thermal, optical, structural, and electrical isolation analyses performed in the investigation indicate the major factors in the design of terrestrial photovoltaic modules. For defect-free materials, minimum encapsulation thicknesses are determined primarily by structural considerations. Cell temperature is not strongly affected by encapsulant thickness or thermal conductivity. The emissivity of module surfaces exerts a significant influence on cell temperature. Encapsulants should be elastomeric, and ribs are required on substrate modules. Aluminum is unsuitable as a substrate material. Antireflection coating is required on cell surfaces.
Garcia, A., III↗
Origins of the protein synthesis cycle
Largely derived from experiments in molecular evolution, a theory of protein synthesis cycles has been constructed. The sequence begins with ordered thermal proteins resulting from the self-sequencing of mixed amino acids. Ordered thermal proteins then aggregate to cell-like structures. When they contained proteinoids sufficiently rich in lysine, the structures were able to synthesize offspring peptides. Since lysine-rich proteinoid (LRP) also catalyzes the polymerization of nucleoside triphosphate to polynucleotides, the same microspheres containing LRP could have synthesized both original cellular proteins and cellular nucleic acids. The LRP within protocells would have provided proximity advantageous for the origin and evolution of the genetic code.
Fox, S. W.↗
Determination of optimum sunlight concentration level in space for 3-5 cascade solar cells
Current-voltage curves were calculated for each cell in a cascade structure using a solar cell diode equation and superposition. Terms for the light generated current, diffusion current, space charge recombination current and series and shunt resistance are included. Individual current voltage curves are added in series with ohmic resistance losses for the cell interconnects to obtain the cascade cell performance. Temperature was varied with concentration, using several models, and ranged from 55 C at one Sun to between 80 and 200 C at 100 Suns. A variety of series resistance and internal resistances were used. Coefficients of the diffusion and recombination terms are strongly temperature dependent. The study indicates that maximum efficiency (30%) occurs in the 50 to 100X Sun concentration range, provided series resistance is below 0.015 ohm-sq cm and cell temperature is 80 C at 100 Suns.
Curtis, H. B.↗
Progress toward cascade cells made by OM-VPE
Organometallic Vapor Phase Epitaxy (COM-VPE) was used to make a sophisticated monolithic cascade cell, with a peak AMO efficiency of 16.6%, not corrected for 14% grid coverage. The cell has 9 epitaxial layers. The top cell is 1.35 microns thick with a 0.1 micron thich emitter. Both cells are heteroface n-p structures. The cascade cell uses metal interconnects. Details of growth and processing are described.
Borden, P. G.↗
Fiberglass Composite Blades for the 4 MW - WTS-4 Wind Turbine
The design and fabrication of composite blades for the WTS-4, a four-megawatt horizontal-axis wind turbine, is discussed. The blade consists of a two-cell, monolithic structure of filament-wound, fiberglass/epoxy composite. Filament winding is a low-cost process which can produce a blade with an aerodynamically efficient airfoil and planform with nonlinear twist to achieve high performance in terms of energy capture. Its retention provides a redundant attachment for long, durable life and safety. Advanced tooling concepts and as sophisticated computer control is used to achieve the unique filament-wound shape.
Bussolari, R. J.↗
Single crystal growth of upgraded metallurgical silicon by HEM for photovoltaic applications
Commercially available metallurgical grade (MG) silicon has high B and P content which is not reduced significantly by directional solidification. By choosing high purity raw materials for an experimental Submerged Electrode Arc Furnace, most of the impurities are reduced to 10 ppmw. Directional solidification of upgraded metallurgical grade (UMG) silicon by the Heat Exchanger Method (HEM) has produced 16 cm x 16 cm cross section ingots with nearly single crystal structure. The main problem encountered during directional solidification was SiC impurities dispersed through the structure. Solar cells fabricated from UMG silicon that was directionally solidified twice by HEM have shown up to 12.33% (am1) conversion efficiency.
Khattak, C. P.↗
Shock-capturing parabolized Navier-Stokes model /SCIPVIS/ for the analysis of turbulent underexpanded jets
A new computational model, SCIPVIS, has been developed to predict the multiple-cell wave/shock structure in under or over-expanded turbulent jets. SCIPVIS solves the parabolized Navier-Stokes jet mixing equations utilizing a shock-capturing approach in supersonic regions of the jet and a pressure-split approach in subsonic regions. Turbulence processes are represented by the solution of compressibility corrected two-equation turbulence models. The formation of Mach discs in the jet and the interactive turbulent mixing process occurring behind the disc are handled in a detailed fashion. SCIPVIS presently analyzes jets exhausting into a quiescent or supersonic external stream for which a single-pass spatial marching solution can be obtained. The iterative coupling of SCIPVIS with a potential flow solver for the analysis of subsonic/transonic external streams is under development.
Dash, S. M.↗
Fully-coupled analysis of jet mixing problems. Part 1. Shock-capturing model, SCIPVIS
A computational model, SCIPVIS, is described which predicts the multiple cell shock structure in imperfectly expanded, turbulent, axisymmetric jets. The model spatially integrates the parabolized Navier-Stokes jet mixing equations using a shock-capturing approach in supersonic flow regions and a pressure-split approximation in subsonic flow regions. The regions are coupled using a viscous-characteristic procedure. Turbulence processes are represented via the solution of compressibility-corrected two-equation turbulence models. The formation of Mach discs in the jet and the interactive analysis of the wake-like mixing process occurring behind Mach discs is handled in a rigorous manner. Calculations are presented exhibiting the fundamental interactive processes occurring in supersonic jets and the model is assessed via comparisons with detailed laboratory data for a variety of under- and overexpanded jets.
Dash, S. M.↗
Interactive phenomena in supersonic jet mixing problems. II - Numerical studies
Applications of the numerical techniques discussed in Part I of this article are presented. Fundamental wave/shear-layer interaction calculations are performed exhibiting the waves produced by high-speed turbulent mixing processes and the interactions of an expansion fan and shock wave with a developing shear layer. Calculations for an underexpanded supersonic jet into a supersonic external stream at different velocity ratios are presented which delineate betweeen weakly interactive and strongly interactive processes in the jet near field. Calculations for the multiple-cell shock structure of an underexpanded jet into still air exhibit the damping of wave intensities by the turbulence and compare quite favorably with available data.
Dash, S. M.↗
Analysis of turbulent underexpanded jets. I - Parabolized Navier-Stokes model, SCIPVIS
A new computational model (SCIPVIS) is described which predicts the multiple-cell wave/shock structure in underexpanded or overexpanded turbulent jets. SCIPVIS solves the parabolized Navier-Stokes jet-mixing equations utilizing a shock-capturing approach in supersonic regions of the jet and a pressure-split approach in subsonic regions. Turbulence processes are represented by the solution of compressibility-corrected two-equation turbulence models. SCIPVIS presently analyzes jets exhausting into a quiescent or supersonic external stream for which a single-pass spatial-marching solution can be obtained. The features of SCIPVIS are reviewed, and calculations are described exhibiting the influence of turbulence modelling, jet temperature, and flight velocity on the jet shock structure.
Dash, S. M.↗