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  • Other Sources  (426)
  • ENERGY PRODUCTION AND CONVERSION  (243)
  • MECHANICAL ENGINEERING  (183)
  • 2010-2014
  • 1990-1994
  • 1980-1984  (426)
  • 1925-1929
  • 1983  (426)
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  • Other Sources  (426)
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  • 2010-2014
  • 1990-1994
  • 1980-1984  (426)
  • 1925-1929
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  • 1
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    Sheet silicon cell/module technology (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The cost involved in the performance of the standard operations for the manufacture of silicon wafers is insignificant in the case of space photovoltaics applications. It is, however, a decisive factor with respect to terrestrial applications of silicon photovoltaic devices. In 1975, a program was, therefore, begun to develop low cost silicon solar arrays for terrestrial applications. The goal was silicon-based photovoltaic (PV) modules ready for installation at a selling price of $0.50/watt (1975 dollars). Sheet and ribbon silicon growth held out the promise of reduced cost through continuous operation, high material throughput, high material utilization efficiency, and a product whose shape lent itself to the assembly of high packing density modules. Attention is given to ribbon growth technologies, sheet technology generic problems, and ribbon cell and module technology status. It is concluded that the potential for crystalline ribbon silicon appears to be better today than ever before.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 2
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    Two-phase turbine staging (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Two-phase turbines would be useful in Rankine cycles using low-quality or saturated-liquid working fluids. The chief problem is low efficiency due to slip losses in nozzles and due to liquid impact and friction losses in rotors. To raise efficiency, a staging method was tested in which the first stage operated at high speed with low relative liquid velocity, and the second stage recovered the first-stage exit energy. The theoretical efficiency for an experimental turbine operating with Refrigerant-22 was raised from 55 percent to 66 percent, and the measured efficiency was raised from 52 percent to 57 percent.
    Keywords: MECHANICAL ENGINEERING
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  • 3
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    DOE/NASA Automotive Stirling Engine Project Overview 83 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An overview of the DOE/NASA Automotive Stirling Engine Project is presented. The background and objectives of the project are reviewed. Project activities are described and technical progress and status are presented and assessed. Prospects for achieving the objective 30 percent fuel economy improvement are considered good. The key remaining technology issues are primarily related to life, reliability and cost, such as piston rod seals, and low cost heat exchanges. Previously announced in STAR as N83-27924
    Keywords: MECHANICAL ENGINEERING
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  • 4
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    Investigation of energy management strategies for photovoltaic systems - A predictive control algorithm (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The present investigation is concerned with the formulation of energy management strategies for stand-alone photovoltaic (PV) systems, taking into account a basic control algorithm for a possible predictive, (and adaptive) controller. The control system controls the flow of energy in the system according to the amount of energy available, and predicts the appropriate control set-points based on the energy (insolation) available by using an appropriate system model. Aspects of adaptation to the conditions of the system are also considered. Attention is given to a statistical analysis technique, the analysis inputs, the analysis procedure, and details regarding the basic control algorithm.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 5
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    Discharge characteristics of a simulated solar cell array (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Measurements of the transient characteristics associated with the discharge of a simulated solar array are presented. A capacitively coupled probe is used to measure the discharge current, and antennas are used to measure the electromagnetic radiation. Discharges were observed at low surface voltages and several modes of discharge were observed. The maximum discharge current is found to be 0.2 A. This value is several orders of magnitude higher than that reported by previous measurements. Experimental evidence suggests that the inverted voltage gradient is a very likely triggering mechanism for solar array discharges.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-30; 4311-431
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  • 6
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    Influence of unbalance on the nonlinear dynamical response and stability of flexible rotor-bearing systems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In this paper, some of the effects of unbalance on the nonlinear response and stability of flexible rotor-bearing systems is presented from both a theoretical and experimental standpoint. In a linear system, operating above its stability threshold, the amplitude of motion grows exponentially with time and the orbits become unbounded. In an actual system, this is not necessarily the case. The actual amplitudes of motion may be bounded due to various nonlinear effects in the system. These nonlinear effects cause limit cycles of motion. Nonlinear effects are inherent in fluid film bearings and seals. Other contributors to nonlinear effects are shafts, couplings and foundations. In addition to affecting the threshold of stability, the nonlinear effects can cause jump phenomena to occur at not only the critical speeds, but also at stability onset or restabilization speeds.
    Keywords: MECHANICAL ENGINEERING
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  • 7
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    Ceramics potential in automotive powerplants (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The paper addresses the potential that ceramic materials can play an important role in future automotive powerplants - both advanced heat engines and advanced battery systems. A number of related experimental programs are reviewed including ceramics for gasoline and diesel piston engines, gas turbine and Stirling Engines and sodium-sulfur batteries. A strong integrated program to develop ceramics technology is recommended.
    Keywords: MECHANICAL ENGINEERING
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  • 8
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    Into mesh lubrication of spur gears with arbitrary offset oil jet. I - For jet velocity less than or equal to gear velocity (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An analysis was conducted for into mesh oil jet lubrication with an arbitrary offset and inclination angle from the pitch point for the case where the oil jet velocity is equal to or less than pitch line velocity. The analysis includes the case for the oil jet offset from the pitch point in the direction of the pinion and where the oil jet is inclined to intersect the common pitch point. Equations were developed for the minimum oil jet velocity required to impinge on the pinion or gear and the optimum oil jet velocity to obtain the maximum impingement depth.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME; 713-718
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  • 9
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    An overview of the Goldstone Energy Systems study (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A systems planning methodology was developed for analyzing and synthesizing Deep Space Network (DSN) energy systems. The resultant product, the Deep Space Network Planning and Analysis Methodology supports DSN energy planning evaluations. It addresses a broad spectrum of tradeoff and dispatching scenarios. It evaluates a variety of energy generation configurations and also includes a capability to evaluate conservation measures.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Telecommun. and Data Acquisition Rept.; p 135-141
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  • 10
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    Efficient computerized model for dynamic analysis of energy conversion systems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In searching for the optimum parameters that minimize the total life cycle cost of an energy conversion system, various combinations of components are examined and the resulting system performance and associated economics are studied. The systems performance and economics simulation computer program (SPECS) was developed to fill this need. The program simulates the fluid flow, thermal, and electrical characteristics of a system of components on a quasi-steady state basis for a variety of energy conversion systems. A unique approach is used in which the set of characteristic equations is solved by the Newton-Raphson technique. This approach eliminates the tedious iterative loops which are found in comparable programs such as TRNSYS or SOLTES-1. Several efficient features were also incorporated such as the centralized control and energy management scheme, and analogous treatment of energy flow in electrical and mechanical components, and the modeling of components of similar fundamental characteristics using generic subroutines. Initial tests indicate that this model can be used effectively with a relatively small number of time steps and low computer cost.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Telecommun. and Data Acquisition Rept.; p 161-176
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  • 11
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    Performance simulation of the JPL solar-powered distiller. Part 1: Quasi-steady-state conditions (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A 37.85 cu m (10,000 gallons) per year (nominal) passive solar powered water distillation system was installed and is operational in the Venus Deep Space Station. The system replaced an old, electrically powered water distiller. The distilled water produced with its high electrical resistivity is used to cool the sensitive microwave equipment. A detailed thermal model was developed to simulate the performance of the distiller and study its sensitivity under varying environment and load conditions. The quasi-steady state portion of the model is presented together with the formulas for heat and mass transfer coefficients used. Initial results indicated that a daily water evaporation efficiency of 30% can be achieved. A comparison made between a full day performance simulation and the actual field measurements gave good agreement between theory and experiment, which verified the model.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Telecommun. and Data Acquisition Rept.; p 142-160
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  • 12
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    Long term technology development program (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: In the Advanced Adiabatic Development program, the following technology were identified as critical: piston development for oil-less, adiabatic engine; positive displacement compounding and charge system; experimental evaluation of the preheat concept; combustion system with positive ignition assist; and ceramic manufacturing technology. Of these five areas, ceramic manufacturing technology is the pacing item, and is already being addressed by several organizations. Therefore the four remaining areas need immediate attention. Since the lead time involved in engine development and production is long, this technology development should be done concurrently with the AAD engine development. A four year program is outlined which will simultaneously study these first four areas. This program requires two test rigs; one single cylinder adiabatic engine; and one multicylinder adiabatic turbocompound engine.
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program; 7 p
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  • 13
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    A.A.D. engine noise evaluation (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A critique of the various characteristics of engine design influencing noise and attempts to indicator areas where attention is required to obtain noise acceptable engine for automobiles are discussed. It was concluded that the engine has a potential to be quiet beccause a ion rated speed is chosen. Problems with high gas pressure, the fuel injection pump, and the expander/compressor are discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: Cummins Engine Co., Inc. Advan. Automotive Diesel Assessment Program; 29 p
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  • 14
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    Screw expander for light duty diesel engines (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Preliminary selection and sizing of a positive displacement screw compressor-expander subsystem for a light-duty adiabatic diesel engine; development of a mathematical model to describe overall efficiencies for the screw compressor and expander; simulation of operation to establish overall efficiency for a range of design parameters and at given engine operating points; simulation to establish potential net power output at light-duty diesel operating points; analytical determination of mass moments of inertia for the rotors and inertia of the compressor-expander subsystem; and preparation of engineering layout drawings of the compressor and expander are discussed. As a result of this work, it was concluded that the screw compressor and expander designed for light-duty diesel engine applications are viable alternatives to turbo-compound systems, with acceptable efficiencies for both units, and only a moderate effect on the transient response.
    Keywords: MECHANICAL ENGINEERING
    Type: Cummins Engine Co., Inc. Advan. Automotive Diesel Assessment Program; 46 p
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  • 15
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    Thermal and mechanical analysis of major components for the advanced adiabatic diesel engine (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The proposed design for the light duty diesel is an in-line four cylinder spark assisted diesel engine mounted transversely in the front of the vehicle. The engine has a one piece cylinder head, with one intake valve and one exhaust valve per cylinder. A flat topped piston is used with a cylindrical combustion chamber recessed into the cylinder head directly under the exhaust valve. A single ceramic insert is cast into the cylinder head to insulate both the combustion chamber and the exhaust port. A similar ceramic insert is cast into the head to insulate the intake port. A ceramic faceplate is pressed into the combustion face of the head to insulate the face of the head from hot combustion gas. The valve seats are machined directly into the ceramic faceplate for the intake valve and into the ceramic exhaust pot insert for the exhaust valve. Additional ceramic applications in the head are the use of ceramic valve guides and ceramic insulated valves. The ceramic valve guides are press fit into the head and are used for increased wear resistance. The ceramic insulated valves are conventional valves with the valve faces plasma spray coated with ceramic for insulation.
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program; 65 p
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  • 16
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    Advanced automotive diesel engine system study (1983)
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    Publication Date: 2011-08-19
    Description: A conceptual study of an advanced automotive diesel engine is discussed. The engine concept selected for vehicle installation was a supercharged 1.4 liter, 4 cylinder spark assisted diesel of 14:1 compression ratio. A compounding unit consisting of a Lysholm compressor and expander is connected to the engine crankshaft by a belt drive. The inlet air charge is heated by the expander exhaust gas via a heat exchanger. Four levels of technology achievement on the selected engine concept were evaluated, from state-of-the-art to the ideal case. This resulted in the fuel economy increasing from 53.2 mpg to 81.7 mpg, and the 0-60 mph time decreasing from 17.6 seconds to 10.9 seconds.
    Keywords: MECHANICAL ENGINEERING
    Type: Cummins Engine Co., Inc. Advan. Automotive Diesel Assessment Program; 18 p
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  • 17
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    A study of the Armstrong Whitworth swing beam engine for automotive application (1983)
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    Publication Date: 2011-08-19
    Description: The introduction of ceramics to those parts suffering high thermal loading was successfully demonstrated, and there is no question that the 100 kw (134 hp) naturally aspirated engine of the future will be developed to produce up to 300 kw (402 hp) by the application of turbocharging or its equivalent. However, at the 60 - 80 kw (80 - 107 hp) size needed for the economic automotive engine, scaling down the 300 kw (402 hp) is beset by the laws of scale. The conventional four stroke diesel was not shown to be successful at the small high speed engine size. The opposed piston two stroke engine does not suffer the same laws of scale and engines in the low power range have already been marketed successfully. The half liter/cylinder Armstrong Whitworth Swing Beam Engine is the latest to be designed with the automotive market in mind. Its low noise structure and balanced linkage system coupled with advantages for easy start and potential use of low grade fuels, derived from its variable compression ratio and slow piston motion, qualifies it for the application.
    Keywords: MECHANICAL ENGINEERING
    Type: Cummins Engine Co., Inc. Advan. Automotive Diesel Assessment Program; 3 p
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  • 18
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    Roller crosshead analysis (1983)
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    Publication Date: 2011-08-19
    Description: An analysis of the frictional behavior of a roller crosshead configuration is given. This configuration consists of a piston which carries at the wristpin position a roller of large diameter which can roll on the cylinder liner surfaces. A preliminary assessment is given of whether the roller can roll on the cylinder liner without skidding, and what, if any, are the tribological implications of this approach to a dry lubricated design. The rotational speed of the roller must change during the stroke if it is not to slip on the cylinder liner. The maximum value of angular acceleration occurs at top dead center and bottom dead center. If the traction force on the rim of the roller, which is the product of the normal force due to piston side load and the coefficient of friction, is not sufficient to drive the roller through the necessary angular acceleration, sliding will occur. At 1,000 rpm, it appears that there will be a definite area of slip near each end of the stroke. The length of the area of slip may be of the order of 1/8 inch at each of these points.
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program; 9 p
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  • 19
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    Advanced Automotive Diesel Assessment Program, executive summary (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The objectives of this analytical study were: to select one advanced automotive diesel engine (AAD) concept which would increase the tank mileage of a 3,000 pound passenger car from the present 35 mpg to at least 52 mpg; to identify long term component research and development work required to bring the selected concept to fruition; and to prepare a development strategy that will bring the selected concept to a prototype testing phase. Cummins Engine Company has completed this study. The selected concept is a 4 stroke cycle, direct injection, spark assisted, advanced adiabatic diesel engine with positive displacement compounding plus expander and part load air preheating. The engine does not use a liquid coolant nor liquid lubricants. It is a 4 cylinder, in-line, 77 mm bore x 77 mm stroke, 1.434 liters displacement engine weighing 300 lb, and rated at 70 BHP at 3000 rpm. Installation dimensions are 621 mm length x 589 mm width x 479 mm height (24.4 inch x 22 inch x 18.9 inch).
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program p; 59 p
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  • 20
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    Detailed performance analysis of the A.A.D. - concept B (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: New concepts for engine performance improvement are seen through the adoption of heat regeneration techniques; advanced methods to enhance the combustion; and higher efficiency air handling machinery, such as the positive displacement helical screw expander and compressor. Each of these concepts plays a particular role in engine performance improvement. First regeneration has a great potential for achieving higher engine thermal efficiency through the recovery of waste energy. Although the concept itself is not new (this technique is used in the gas turbine), the application to reciprocating internal combustion engines is quite unusual and presents conceptual difficulties. The second important area is better control of the combustion process in terms of heat transfer characteristics, combustion products, and heat release rate. The third area for performance improvement is in the adoption of high efficiency air handling machinery. In particular, positive displacement helical expander and compressor exhibit an extremely high efficiency over a wide range of operating conditions.
    Keywords: MECHANICAL ENGINEERING
    Type: Advan. Automotive Diesel Assessment Program; 46 p
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  • 21
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    Single cell performance studies on the FE/CR Redox Energy Storage System using mixed reactant solutions at elevated temperature (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Experimental studies in a 14.5 sq cm single cell system using mixed reactant solutions at 65 C are described. Systems were tested under isothermal conditions, i.e., reactants and the cell were at the same temperature. Charging and discharging performance were evaluated by measuring watt-hour and coulombic efficiencies, voltage-current relationships, hydrogen evolution and membrane resistivity. Watt-hour efficiencies ranged from 86 percent at 43 ma/sq cm to 75 percent at 129 ma/sq cm with corresponding coulombic efficiencies of 92 percent and 97 percent, respectively. Hydrogen evolution was less than 1 percent of the charge coulumbic capacity during charge-discharge cycling. Bismuth amd bismuth-lead catalyzed chromium electrodes maintained reversible performance and low hydrogen evolution under normal and adverse cycling conditions. Reblending of the anode and cathode solutions was successfully demonstrated to compensate for osmotic volume changes. Improved performance was obtained with mixed reactant systems in comparison to the unmixed reactant systems. Previously announced in STAR as N83-25042
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 22
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    The DOE photovoltaics program (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The considered program of the U.S. Department of Energy (DOE) has the objective to provide federal support for research and development work related to photovoltaics. According to definitions of policy in 1981, a strong emphasis is to be placed on long-term, high-risk research and development that industry could not reasonably be expected to perform using their own funds. Attention is given to the program structure, the photovoltaics program management organization, the advanced research and development subprogram, the collector research and development subprogram, flat-plate collectors, concentrator collectors, and the systems research and technology subprogram.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 23
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    Silicon material technology status (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Silicon has been the basic element for the electronic and photovoltaic industries. The use of silicon as the primary element for terrestrial photovoltaic solar arrays is projected to continue. The reasons for this projection are related to the maturity of silicon technology, the ready availability of extremely pure silicon, the performance of silicon solar cells, and the considerable present investment in technology and manufacturing facilities. The technologies for producing semiconductor grade silicon and, to a lesser extent, refined metallurgical grade silicon are considered. It is pointed out that nearly all of the semiconductor grade silicon is produced by processes based on the Siemens deposition reactor, a technology developed 26 years ago. The state-of-the-art for producing silicon by this process is discussed. It is expected that efforts to reduce polysilicon process costs will continue.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 24
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    Systems approach to walk-off problems for dish-type solar thermal power systems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: 'Walk-off' in a dish-type solar thermal power system is a failure situation in which the concentrator remains fixed while the spot of concentrated sunlight slowly moves across the face of the receiver. The intense local heating may damage the receiver and nearby equipment. Passive protection has advantages in minimizing damage, but in a fully passive design the receiver must be able to withstand full solar input with no forced fluid circulation during the walk-off. An active walk-off emergency subsystem may include an emergency detrack or defocus mechanism or sun-blocking device, emergency power, sensors and logic to detect the emergency and initiate protective action, and cooling or passive protection of emergency and non-emergency components. Each of these elements is discussed and evaluated in the paper.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 25
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    Practical small-scale explosive seam welding (1983)
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    Publication Date: 2011-08-18
    Description: A small-scale explosive seam welding process has been developed that can significantly contribute to remote metal joining operations under hazardous or inaccessible conditions, such as nuclear reactor repair and assembly of structure in space. This paper describes this explosive seam welding process in terms of joining principles, variables, types of joints created, capabilities, and applications. Very small quantities of explosive in a ribbon configuration are used to create narrow (less than 0.5 inch), long-length, uniform, hermetically sealed joints that exhibit parent metal properties in a wide variety of metals, alloys, and combinations. The practicality of this process has been demonstrated by its current acceptance, as well as its capabilities that are superior in many applications to the universally accepted joining processes, such as mechanical fasteners, fusion and resistance welding, and adhesives. Previously announced in STAR as N83-24896
    Keywords: MECHANICAL ENGINEERING
    Type: (ISSN 0025-6501)
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  • 26
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    Plasma-enhanced CVD silicon nitride antireflection coatings for solar cells (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Multilayer plasma-enhanced chemical vapor deposition (PECVD) silicon nitride antireflection coatings were deposited on space quality silicon solar cells. Preliminary experiments indicated that multilayer coatings decreased the total reflectance of polished silicon from 35 percent to less than 3 percent over the spectral range 0.4-1.0 micron. The solar cell energy conversion efficiency was increased from an average of 8.84 percent to an average of 12.63 percent.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy (ISSN 0038-092X); 31; 4, 19; 1983
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  • 27
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    Whirl flutter analysis of a horizontal-axis wind turbine with a two-bladed teetering rotor (1983)
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    Publication Date: 2011-08-18
    Description: Whirl flutter and the effect of pitch-flap coupling on teetering motion of a wind turbine were investigated. The equations of motion are derived for an idealized five-degree-of-freedom mathematical model of a horizontal-axis wind turbine with a two-bladed teetering rotor. The model accounts for the out-of-plane bending motion of each blade, the teetering motion of the rotor, and both the pitching and yawing motions of the rotor support. Results show that the design is free from whirl flutter. Selected results are presented indicating the effect of variations in rotor support damping, rotor support stiffness, and pitch-flap coupling on pitching, yawing, teetering, and blade bending motions. Previously announced in STAR as N82-23707
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy (ISSN 0038-092X); 31; 2, 19; 1983
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  • 28
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    Thermal behavior of laboratory models of honeycomb-covered solar ponds (1983)
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    Publication Date: 2011-08-18
    Description: Laboratory experiments were conducted to provide insight into the technical feasibility of honeycomb-covered solar ponds. Cooling tests using honeycomb panels of various materials and geometries showed that a 5.7-cm-thick one-tier panel insulated as effectively as a 10-cm fiberglass slab. Heating tests demonstrated that a model pond covered with a polycarbonate panel boiled upon 16 hours of continuous exposure to a 150-W spotlight. Analysis of the experimental data indicates positively that honeycomb-covered solar ponds can be expected to perform satisfactorily, and that larger-scale outdoor tests should be conducted to provide a more realistic assessment and a more refined performance estimate.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 29
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    Expected cycle life vs. depth of discharge relationships of well-behaved single cells and cell strings (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The present investigation is concerned with the factors which might influence the cycle life vs. depth of discharge relationship, taking into account the rate of loss of cell capacity, the amount of excess capacity built into the cells, and the penalty in capacity loss resulting from the use of deep depths of discharge. 'First principles' are used to develop a cell life model for somewhat arbitrary conditions. This model is then used to estimate the cycle life vs. depth of discharge relationships for 'well behaved' cells. The stochastic variations associated with groupings of single cells are then introduced to the battery pack cycle life model. The term 'well behaved' cell is used to describe a single cell which does not suffer any abrupt failure mode during the course of its operation. It gradually loses capacity for any number of the usual reasons at a rate which is the product of the fractional depth of discharge and a factor which is characteristic of the cell under consideration.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Electrochemical Society, Journal (ISSN 0013-4651); 130; May 1983
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    Solar concentrator degradation in Low Earth Orbit (LEO) (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The use of parabolically or spherically-shaped mirrors is being considered in order to increase the solar energy intensity on solar cells. Their use will significantly decrease the size and number of the cells needed for a particular application, hence the total array cost. Questions arise, however, regarding the long-term (five to ten years) efficiency of these devices. Performance degradation of the mirror surfaces might result from known hostile elements in the low earth orbit (LEO) environment (150-350 nautical miles). The degradation issue is addressed in light of present knowledge of this environment. The following characteristics of the LEO environment are identified for study: (1) the vacuum of space; (2) sputtering by the residual atoms and particles in space; (3) solar electromagnetic radiation; (4) contamination of the mirror surface; (5) atomic oxygen interactions with the surface; (6) bombardment of the surface by meteoroids; and (7) irradiation of the surface by ionizing particles (protons). Using the best available information for the magnitudes of the necessary quantities, a mathematical analysis was carried out, where possible, to determine the degradation in reflectance or other loss caused by each characteristic. Otherwise, reasonable estimates are made of corresponding losses, based on already published data.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Johnson (Lyndon B.) Space Center The 1983 NASA/ASEE Summer Faculty Fellowship Research Program Research Reports; NASA. Johnson (Lynd
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    Laser assisted deposition (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Applications of laser-based processing techniques to solar cell metallization are discussed. Laser-assisted thermal or photolytic maskless deposition from organometallic vapors or solutions may provide a viable alternative to photovoltaic metallization systems currently in use. High power, defocused excimer lasers may be used in conjunction with masks as an alternative to direct laser writing to provide higher throughput. Repeated pulsing with excimer lasers may eliminate the need for secondary plating techniques for metal film buildup. A comparison between the thermal and photochemical deposition processes is made.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 317-332
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    Metallization with generic metallo-organic inks (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The use and fabrication of metallo-organic films are discussed. Metallo-organic compounds are ones in which a metal is linked to a long chain carbon ligand through a hetero atom such as O, S, N, P or As. Films formed by the thermal decomposition of these metallo-organics are called MOD films. In order that the products of decomposition contain only CO2, H2O, and in rare cases nitrogen compounds, and to avoid S containing products, the use of a set of metallo-organic compounds for ink fabrication where the linking hetero atom was oxygen was pioneered. These links were made from commercially available carboxylates, or synthesized from commonly available reagents. The processing is described and the molecular design criteria are given. The particular carboxylates or amine carboxylates selected were the octoates or neodecanoates, and they are described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 277-300
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    Solar cell metallization: Historical perspective (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Solar cell metallization design requirements are discussed. Space applications and terrestrial applications are considered. Cost factors are discussed in relation to design analysis.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 9-18
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    Economic implications of current systems (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The primary goals of this study are to estimate the value of R&D to photovoltaic (PV) metallization systems cost, and to provide a method for selecting an optimal metallization method for any given PV system. The value-added cost and relative electrical performance of 25 state-of-the-art (SOA) and advanced metallization system techniques are compared.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 19-33
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  • 35
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    Unified Analysis for Antenna Pointing and Structural Errors. Part 1. Review (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-10
    Description: A necessary step in the design of a high accuracy microwave antenna system is to establish the signal error budget due to structural, pointing, and environmental parameters. A unified approach in performing error budget analysis as applicable to ground-based microwave antennas of different size and operating frequency is discussed. Major error sources contributing to the resultant deviation in antenna boresighting in pointing and tracking modes and the derivation of the governing equations are presented. Two computer programs (SAMCON and EBAP) were developed in-house, including the antenna servo-control program, as valuable tools in the error budget determination. A list of possible errors giving their relative contributions and levels is presented.
    Keywords: MECHANICAL ENGINEERING
    Type: The Telecommun. and Data Acquisition Rept.; p 40-59
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  • 36
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    Ferrographic and spectrometer oil analysis from a failed gas turbine engine (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An experimental gas turbine engine was destroyed as a result of the combustion of its titanium components. It was concluded that a severe surge may have caused interference between rotating and stationary compressor parts that either directly or indirectly ignited the titanium components. Several engine oil samples (before and after the failure) were analyzed with a Ferrograph, and with plasma, atomic absorption, and emission spectrometers to see if this information would aid in the engine failure diagnosis. The analyses indicated that a lubrication system failure was not a causative factor in the engine failure. Neither an abnormal wear mechanism nor a high level of wear debris was detected in the engine oil sample taken just prior to the test in which the failure occurred. However, low concentrations (0.2 to 0.5 ppm) of titanium were evident in this sample and samples taken earlier. After the failure, higher titanium concentrations (2 ppm) were detected in oil samples taken from different engine locations. Ferrographic analysis indicated that most of the titanium was contained in spherical metallic debris after the failure. The oil analyses eliminated a lubrication system bearing or shaft seal failure as the cause of the engine failure. Previously announced in STAR as N83-12433
    Keywords: MECHANICAL ENGINEERING
    Type: Wear (ISSN 0043-1648); 90; 239-249
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    Photovoltaic power - An important new energy option (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A review of photovoltaic (PV) power technology is presented with an emphasis of PV as an economical and technically feasible alternative source of energy. The successful completion of the development and transfer of emerging low-cost technologies into a fully commercialized status are identified as the means to the realization of this option's full potential. The DOE National Photovoltaics Program, a significant sponsor of PV R&D, expects both flat-plate and concentrator collectors to meet established cost targets. Citing the DOE large flat-plate grid-connected system project of the Sacramento Municipal Utility District, current technology modules priced at near $5/Wp (1983 dollars) are steadily reducing costs. A recent DOE study suggests that PV-generated electricity produced at a 30-year levelized cost of 15 cents per kWh would represent a viable energy supply alternative for the nation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Mechanical Engineering (ISSN 0025-6501); 105; 16-23
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  • 38
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    Metal shell technology (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Metallic shells are fabricated for a size range from several millimeters down to less than 500 microns in diameter. The technology, developed at JPL, is based on the hollow-jet instability for the large-shell formation, and in addition, on the Bernoulli's force for the microbubble generation. Various materials were processed into hollow spheres, such as AL1100, tin, lead, and a metallic glass-forming alloy, AuPbSb. They exhibited a range of contrasting solidification behaviors and surface characteristics. Some of their potential applications will be explored in this paper.
    Keywords: MECHANICAL ENGINEERING
    Type: SAMPE Journal (ISSN 0091-1062); 19; 7-11
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  • 39
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    Harnessing surface plasmons for solar energy conversion (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: NASA research on the feasibility of solar-energy conversion using surface plasmons is reviewed, with a focus on inelastic-tunnel-diode techniques for power extraction. The need for more efficient solar converters for planned space missions is indicated, and it is shown that a device with 50-percent efficiency could cost up to 40 times as much per sq cm as current Si cells and still be competitive. The parallel-processing approach using broadband carriers and tunable diodes is explained, and the physics of surface plasmons on metal surfaces is outlined. Technical problems being addressed include phase-matching sunlight to surface plasmons, minimizing ohmic losses and reradiation in energy transport, coupling into the tunnels by mode conversion, and gaining an understanding of the tunnel-diode energy-conversion process. Diagrams illustrating the design concepts are provided.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 40
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    Thermodynamic analysis of journal bearings operating under steady state loading in laminar regime (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Thermohydrodynamic effects in journal bearings operating under steady load in laminar regime are investigated. An analytical model for the finite and infinitely long journal bearings is formulated. The model includes correction factors for the cavitation effects in the unloaded region of the bearing and the mixing of the recirculating oil and supply oil at the oil inlet. A finite difference computer program is developed to numerically solve the governing equations of the continuity, Reynolds, energy, Laplace heat conduction, and a viscosity-temperature relation simultaneously. The program includes a numerical technique for obtaining an isothermal shaft temperature. The numerical results of temperature distribution and the heat effects on the bearing load carrying capacity agree closely with those of experimental findings. Several different sets of simpler boundary conditions for the energy equation are studied.
    Keywords: MECHANICAL ENGINEERING
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    Thermoelectric energy conversion with solid electrolytes (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The alkali metal thermoelectric converter (AMTEC) is a device for the direct conversion of heat to electrical energy. The sodium ion conductor beta-double prime-alumina is used to form a high-temperature regenerative concentration cell for elemental sodium. An AMTEC of mature design should have an efficiency of 20 to 40 percent, a power density of 0.5 kilowatt per kilogram or more, no moving parts, low maintenance requirements, high durability, and efficiency independent of size. It should be usable with high-temperature combustion, nuclear, or solar heat sources. Experiments have demonstrated the feasibility of the AMTEC and confirmed the theoretical analysis of the device. A wide range of applications from aerospace power to utility power plants appears possible.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Science (ISSN 0036-8075); 221; Sept. 2
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  • 42
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    Analysis of the interaction of an electron beam with back surface field solar cells (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In this paper the short circuit current Isc induced by the electron beam of a scanning electron microscope in a back surface field solar cell will be determined theoretically. It will be shown that, in a configuration used previously for solar cells with an ohmic back surface, the Isc gives a convenient means for estimating the back surface recombination velocities and thus the quality of back surface field cells. Numerical data will be presented applicable to a point source model for the electron-hole pair generation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Applied Physics (ISSN 0021-8979); 54; July 198
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  • 43
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    Dish concentrators for solar thermal energy (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 03, p. 397, Accession no. A82-14001
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: (ISSN 0146-0412)
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  • 44
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    Solar thermal technologies - Potential benefits to U.S. utilities and industry (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Solar energy systems were investigated which complement nuclear and coal technologies as a means of reducing the U.S. dependence on imported petroleum. Solar Thermal Energy Systems (STES) represents an important category of solar energy technologies. STES can be utilized in a broad range of applications servicing a variety of economic sectors, and they can be deployed in both near-term and long-term markets. The net present value of the energy cost savings attributable to electric utility and IPH applications of STES were estimated for a variety of future energy cost scenarios and levels of R&D success. This analysis indicated that the expected net benefits of developing an STES option are significantly greater than the expected costs of completing the required R&D. In addition, transportable fuels and chemical feedstocks represent a substantial future potential market for STES. Due to the basic nature of this R&D activity, however, it is currently impossible to estimate the value of STES in these markets. Despite this fact, private investment in STES R&D is not anticipated due to the high level of uncertainty characterizing the expected payoffs. Previously announced in STAR as N83-10547
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Energy (ISSN 0146-0412); 7; July-Aug
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  • 45
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    The influence of surface dents and grooves on traction in sliding EHD point contacts (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Changes in traction, caused by dents and grooves on a highly polished ball, are investigated as these defects approach and go through sliding elastohydrodynamic point contacts. The contacts are formed with the ball loading against a transparent disk. The ball and thus the topographical features are held stationary at various locations in the vicinity and within the contact while the disk is rotating. These topographical features can cause substantial changes in the traction when compared to traction obtained with smooth surfaces. Previously announced in STAR as N82-32734
    Keywords: MECHANICAL ENGINEERING
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  • 46
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    Plastic deformation and wear process at a surface during unlubricated sliding (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The plastic deformation and wear of a 304 stainless steel surface sliding against an aluminum oxide rider with a spherical surface (the radius of curvature: 1.3 cm) were observed by using scanning electron and optical microscopes. Experiments were conducted in a vacuum of one million Pa and in an environment of fifty thousandth Pa of chlorine gas at 25 C. The load was 500 grams and the sliding velocity was 0.5 centimeter per second. The deformed surface layer which accumulates and develops successively is left behind the rider, and step shaped proturbances are developed even after single pass sliding under both environmental conditions. A fully developed surface layer is gradually torn off leaving a characteristic pattern. The mechanism for tearing away of the surface layer from the contact area and sliding track contour is explained assuming the simplified process of material removal based on the adhesion theory for the wear of materials. Previously announced in STAR as N82-32735
    Keywords: MECHANICAL ENGINEERING
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    Correlation of solar cell electrical properties with material characteristics of silicon cast by the ubiquitous crystallization process (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Solar cells were fabricated using a conservative 'baseline' process on 1-3 Omega-cm p-type silicon from ingots cast by the ubiquitous crystallization process. Conversion efficiencies of the cells were measured, as well as spectral response and minority carrier diffusion length. Adjacent slices from the same ingot were studied for their grain size, dislocation distribution, and impurity distribution. Cell performance was related to the observed structural features, as well as to the chemical structure of the ingot.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Electrochemical Society, Journal (ISSN 0013-4651); 130; June 198
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  • 48
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    Configuration selection study for isolated loads (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 06, p. 900, Accession no. A82-18223)
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 49
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    Optimization of dish solar collectors (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Methods for optimizing parabolic dish solar collectors and the consequent effects of various optical, thermal, mechanical, and cost variables are examined. The most important performance optimization is adjusting the receiver aperture to maximize collector efficiency. Other parameters that can be adjusted to optimize efficiency include focal length, and, if a heat engine is used, the receiver temperature. The efficiency maxima associated with focal length and receiver temperature are relatively broad; it may, accordingly, be desirable to design somewhat away from the maxima. Performance optimization is sensitive to the slope and specularity errors of the concentrator. Other optical and thermal variables affecting optimization are the reflectance and blocking factor of the concentrator, the absorptance and losses of the receiver, and, if a heat engine is used, the shape of the engine efficiency versus temperature curve. Performance may sometimes be improved by use of an additional optical element (a secondary concentrator) or a receiver window if the errors of the primary concentrator are large or the receiver temperature is high. Previously announced in STAR as N83-19224
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Energy (ISSN 0146-0412); 7; 684-694
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    Limits to solar power conversion efficiency with applications to quantum and thermal systems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An analytical framework is presented that permits examination of the limit to the efficiency of various solar power conversion devices. Thermodynamic limits to solar power efficiency are determined for both quantum and thermal systems, and the results are applied to a variety of devices currently considered for use in space systems. The power conversion efficiency for single-threshold energy quantum systems receiving unconcentrated air mass zero solar radiation is limited to 31 percent. This limit applies to photovoltaic cells directly converting solar radiation, or indirectly, as in the case of a thermophotovoltaic system. Photoelectrochemical cells rely on an additional chemical reaction at the semiconductor-electrolyte interface, which introduces additional second-law demands and a reduction of the solar conversion efficiency. Photochemical systems exhibit even lower possible efficiencies because of their relatively narrow absorption bands. Solar-powered thermal engines in contact with an ambient reservoir at 300 K and operating at maximum power have a peak conversion efficiency of 64 percent, and this occurs for a thermal reservoir at a temperature of 2900 K. The power conversion efficiency of a solar-powered liquid metal magnetohydrodydnamic generator, a solar-powered steam turbine electric generator, and an alkali metal thermoelectric converter is discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Energy (ISSN 0146-0412); 7; 581-588
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    Pore size engineering applied to the design of separators for nickel-hydrogen cells and batteries (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Pore size engineering in starved alkaline multiplate cells involves adopting techniques to widen the volume tolerance of individual cells. Separators with appropriate pore size distributions and wettability characteristics (capillary pressure considerations) to have wider volume tolerances and an ability to resist dimensional changes in the electrodes were designed. The separators studied for potential use in nickel-hydrogen cells consist of polymeric membranes as well as inorganic microporous mats. In addition to standard measurements, the resistance and distribution of electrolyte as a function of total cell electrolyte content were determined. New composite separators consisting of fibers, particles and/or binders deposited on Zircar cloth were developed in order to engineer the proper capillary pressure characteristics in the separator. These asymmetric separators were prepared from a variety of fibers, particles and binders. Previously announced in STAR as N83-24571
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    Test results of a ten cell bipolar nickel-hydrogen battery (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A ten cell bipolar nickel hydrogen 6.5 ampere-hour battery demonstrated over 2000 low earth orbit cycles at an 80 percent depth-of-discharge. Charge/discharge cyclic ampere-hour and watt-hour efficiencies of 88 and 76 percent, respectively, observed. Peak power capability was determined at 1.1 kW. A 10C discharge rate yields 83 percent of the nominal stark capacity to the 1.0 volt cut off in just under 6 minutes. Previously announced in STAR as N83-26253
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 53
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    Cycle life test and failure model of nickel-hydrogen cells (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Six ampere hour individual pressure vessel nickel hydrogen cells were charge/discharge cycled to failure. Failure as used here is defined to occur when the end of discharge voltage degraded to 0.9 volts. They were cycled under a low earth orbit cycle regime to a deep depth of discharge (80 percent of rated ampere hour capacity). Both cell designs were fabricated by the same manufacturer and represent current state of the art. A failure model was advanced which suggests both cell designs have inadequate volume tolerance characteristics. The limited existing data base at a deep depth of discharge (DOD) was expanded. Two cells of each design were cycled. One COMSAT cell failed at cycle 1712 and the other failed at cycle 1875. For the Air Force/Hughes cells, one cell failed at cycle 2250 and the other failed at cycle 2638. All cells, of both designs, failed due to low end of discharge voltage (0.9 volts). No cell failed due to electrical shorts. After cell failure, three different reconditioning tests (deep discharge, physical reorientation, and open circuit voltage stand) were conducted on all cells of each design. A fourth reconditioning test (electrolyte addition) was conducted on one cell of each design. In addition post cycle cell teardown and failure analysis were performed on the one cell of each design which did not have electrolyte added after failure. Previously announced in STAR as N83-25038
    Keywords: ENERGY PRODUCTION AND CONVERSION
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    Investigation of indigenous water, salt and soil for solar ponds (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The existence of salt-gradient solar ponds in nature is a strong indication that the successful exploitation of this phenomenon must account adequately for the influences of the local setting. Sun, weather and other general factors are treated elsewhere. This paper deals with water, salt, and soil. A general methodology for evaluating and, where feasible, adjusting the effects of these elements is under development. Eight essential solar pond characteristics have been identified, along with a variety of their dependencies upon properties of water, salt and soil. The comprehensive methodology, when fully developed, will include laboratory investigation in such diverse areas as brine physical chemistry, light transmission, water treatment, brine-soil interactions, sealants, and others. With the Salton Sea solar pond investigation as an example, some methods under development will be described.
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    A system study of the solar power satellite concept (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The paper summarizes a system study of the solar power satellite (SPS) concept which was conducted in the 1977-1980 time period. The system study was sponsored by the U.S. Department of Energy and the National Aeronautics and Space Administration as part of an SPS Concept Development and Evaluation Program. A reference system, developed during the study is described. The reference system was subsequently used as a basis for environmental, economic, and societal assessments. The reference system was recognized as probably not being an optimized approach. A number of alternate approaches which were studied in less depth are also described. The paper concludes with a number of observations regarding the SPS concept, and the pertinence of ongoing space technology, development, and flight programs to various aspects of the concept.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Solar Power Review (ISSN 0191-9067); 4; 1-2,
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  • 56
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    Non-noble metal based metallization systems (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The results of efforts to produce a nonsilver metallization system for silicon photovoltaic cells are given. The system uses a metallization system based on molybdenum, tin, and titanium hydride. The initial work in this system was done using the MIDFILM process. The MIDFILM process attains a line resolution comparable to photoresist methods with a process related to screen printing. The surface to be processed is first coated with a thin layer of photopolymer material. Upon exposure to ultraviolet light through a suitable mask, the polymer in the non-pattern area crosslinks and becomes hard. The unexposed pattern areas remain tacky. The conductor material is then applied in the form of a dry mixture of metal which adheres to the tacky pattern area. The assemblage is then fired to ash the photopolymer and sinter the conductor powder.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 215-240
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    Dry etching of metallization (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The production dry etch processes are reviewed from the perspective of microelectronic fabrication applications. The major dry etch processes used in the fabrication of microelectronic devices can be divided into two categories - plasma processes in which samples are directly exposed to an electrical discharge, and ion beam processes in which samples are etched by a beam of ions extracted from a discharge. The plasma etch processes can be distinguished by the degree to which ion bombardment contributes to the etch process. This, in turn is related to capability for anisotropic etching. Reactive Ion Etching (RIE) and Ion Beam Etching are of most interest for etching of thin film metals. RIE is generally considered the best process for large volume, anisotropic aluminum etching.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 301-316
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    Particle size effects on viscosity of silver pastes: A manufacturer's view (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Particles from a variety of silver powders were investigated by scanning electron microscopy and particle size analyses. Particle size distribution curves and volume population graphs were prepared for these silver powders and for glass powders with optimum, extra fine and coarse particle sizes. The viscosity at a given shear rate and slope of viscosity over a range of shear rates were determined for thick film pastes made with these powders. Because of particle anomalies and variations, the need for flexibility to achieve the best printing qualities for silver pastes was evident. It was established that print quality, dried and fired film density and optimum contact of silver particles with silicon, important for cell electrical output, could be achieved by adjusting the slope of viscosity that fell outside of the range, -0.550 to -0.650. This was accomplished through organic vehicle technology that permitted a change in the slope of viscosity, up or down, while maintaining a constant silver and total solids content.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 195-214
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    Module degradation catalyzed by metal-encapsulation reactions (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Four major properties are considered to be relevant in determining service life of a photovoltaic module: (1) Mechanical: creep resistance, modulus, tensile strength; (2) Optical: integrated transmission at 0.4 to 1.1 m wavelength; (3) Chemical: inertness with respect to metals and other components, retention of stabilizers, etc. and (4) Electrical; maintaining effective isolation of conductive components. These properties were measured after exposing polymer specimens to three types of accelerated stress: thermal, ultraviolet radiation and metal catalysts. These conditions give rise to a large number of complex interrelated free-radical reactions that result in the deterioration of polymeric materials.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 147-157
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    Getting the current out (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Progress of a photovoltaic (PV) device from a research concept to a competitive power-generation source requires an increasing concern with current collection. The initial metallization focus is usually on contact resistance, since a good ohmic contact is desirable for accurate device characterization measurements. As the device grows in size, sheet resistance losses become important and a metal grid is usually added to reduce the effective sheet resistance. Later, as size and conversion efficiency continue to increase, grid-line resistance and cell shadowing must be considered simultaneously, because grid-line resistance is inversely related to total grid-line area and cell shadowing is directly related. A PV cell grid design must consider the five power-loss phenomena mentioned above: sheet resistance, contact resistance, grid resistance, bus-bar resistance and cell shadowing. Although cost, reliability and usage are important factors in deciding upon the best metallization system, this paper will focus only upon grid-line design and substrate material problems for flat-plate solar arrays.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 95
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    Diffusion barriers (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The choice of the metallic film for the contact to a semiconductor device is discussed. One way to try to stabilize a contact is by interposing a thin film of a material that has low diffusivity for the atoms in question. This thin film application is known as a diffusion barrier. Three types of barriers can be distinguished. The stuffed barrier derives its low atomic diffusivity to impurities that concentrate along the extended defects of a polycrystalline layer. Sacrificial barriers exploit the fact that some (elemental) thin films react in a laterally uniform and reproducible fashion. Sacrificial barriers have the advantage that the point of their failure is predictable. Passive barriers are those most closely approximating an ideal barrier. The most-studied case is that of sputtered TiN films. Stuffed barriers may be viewed as passive barriers whose low diffusivity material extends along the defects of the polycrystalline host.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 113-136
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    Silicon solar cell characterization at low temperatures and low illumination as a function of particulate irradiation (1983)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Various configurations of back surface reflector silicon solar cells including small (2 x 2) cm and large (approx. 6 x 6) cm cells with conventional and wraparound contacts were subjected to 1 MeV electron irradiation and characterized under both Earth orbital and deep space conditions of temperatures and illuminations. Current-Voltage (I-V) data were generated from +65 C to -150 C and at incident illuminations from 135.3 mW/sq cm to 5.4 mW/sq cm for these cells. Degradation in cell performance which is manifested only under deep space conditions is emphasized. In addition, the effect of particle irradiation on the high temperature and high intensity and low temperature and low intensity performance of the cells is described. The cells with wraparound contacts were found to have lower efficiencies at Earth orbital conditions than the cells with conventional contacts.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: AGARD Environ. Effects on Mater. for Space Appl.; 9 p
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    Linear and Nonlinear Aspects of Rotordynamics (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-10
    Description: Excessive vibrations of the liquid oxygen pump in the Space Shuttle's Main Engine have been recorded during hot firing ground testing. In order to determine mathematical explanations of this possibility, destructive phenomenon differential equations have been examined which describe the rotordynamics of the pump. Modeling the rotor as a random eigenvalue problem was considered. Analytical expressions were derived for the solution in the case of symmetric damping and stiffness. This enables one to determine accuracy estimates when testing numerical techniques to solve both asymmetric and nonlinear problems. Finally, the rotor model has had nonlinear elements incorporated to improve its simulation of the pump and to expand the corresponding mathematical theory.
    Keywords: MECHANICAL ENGINEERING
    Type: Alabama Univ. Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 22 p
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    Sensor Control of Robot Arc Welding (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-12
    Description: The potential for using computer vision as sensory feedback for robot gas-tungsten arc welding is investigated. The basic parameters that must be controlled while directing the movement of an arc welding torch are defined. The actions of a human welder are examined to aid in determining the sensory information that would permit a robot to make reproducible high strength welds. Special constraints imposed by both robot hardware and software are considered. Several sensory modalities that would potentially improve weld quality are examined. Special emphasis is directed to the use of computer vision for controlling gas-tungsten arc welding. Vendors of available automated seam tracking arc welding systems and of computer vision systems are surveyed. An assessment is made of the state of the art and the problems that must be solved in order to apply computer vision to robot controlled arc welding on the Space Shuttle Main Engine.
    Keywords: MECHANICAL ENGINEERING
    Type: Alabama Univ. Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 56 p
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    Secondary electric power generation with minimum engine bleed (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Secondary electric power generation with minimum engine bleed is discussed. Present and future jet engine systems are compared. The role of auxiliary power units is evaluated. Details of secondary electric power generation systems with and without auxiliary power units are given. Advanced bleed systems are compared with minimum bleed systems. A cost model of ownership is given. The difference in the cost of ownership between a minimum bleed system and an advanced bleed system is given.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 37-50
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    Hinge latch mechanism (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The device described in this paper is a modular hinge latch mechanism. It is used to latch and preload four motorized hinges after their deployment. The paper describes design requirements, hardware development and initial testing of this hinge latch module. A special effort has been made to cover the design philosophy incorporated into this hardware.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 343-356
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  • 67
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    Iron-copper metallization for flexible solar/cell arrays (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The feasibility of a copper-base metallization for shallow-junction cells applied in flexible solar arrays in space is discussed. This type of metallization will reduce usage of precious metals (such as silver), increase case of bonding (by welding or by soldering) and eliminate heavy high Z interconnects (such as molybdenum). The main points of concern are stability against thermally induced diffusion of copper into silicon which causes degradation of shallow cell junctions, and low series resistance of the contact with semiconductor which promotes cell efficiency.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 375-394
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    Transparent conductive coatings (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Thin film transparent conductors are discussed. Materials with electrical conductivity and optical transparency are highly desirable in many optoelectronic applications including photovoltaics. Certain binary oxide semiconductors such as tin oxide (SnO2) and indium oxide (In2O3) offer much better performance tradeoff in optoelectronics as well as better mechanical and chemical stability than thin semitransparent films. These thin-film transparent conductors (TC) are essentially wide-bandgap degenerate semiconductors - invariably n-type - and hence are transparent to sub-bandgap (visible) radiation while affording high electrical conductivity due to the large free electron concentration. The principal performance characteristics of TC's are, of course, electrical conductivity and optical transmission. The TC's have a refractive index of around 2.0 and hence act as very efficient antireflection coatings. For using TC's in surface barrier solar cells, the photovoltaic barrier is of utmost importance and so the work function or electron affinity of the TC is also a very important material parameter. Fabrication processes are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 335-363
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    Ionized cluster beam deposition (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Ionized Cluster Beam (ICB) deposition, a new technique originated by Takagi of Kyoto University in Japan, offers a number of unique capabilities for thin film metallization as well as for deposition of active semiconductor materials. ICB allows average energy per deposited atom to be controlled and involves impact kinetics which result in high diffusion energies of atoms on the growth surface. To a greater degree than in other techniques, ICB involves quantitative process parameters which can be utilized to strongly control the characteristics of films being deposited. In the ICB deposition process, material to be deposited is vaporized into a vacuum chamber from a confinement crucible at high temperature. Crucible nozzle configuration and operating temperature are such that emerging vapor undergoes supercondensation following adiabatic expansion through the nozzle.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 265-276
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    Polymer thick-film conductors and dielectrics for membrane switches and flexible circuitry (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The fabrication and operation of membrane switches are discussed. The membrane switch functions as a normally open, momentary contact, low-voltage pressure-sensitive device. Its design is a three-layer sandwich usually constructed of polyester film. Conductive patterns are deposited onto the inner side of top and bottom sheets by silk screening. The center spacer is then placed between the two circuit layers to form a sandwich, generally held together by an adhesive. When pressure is applied to the top layer, it flexes through the punched openings of the spacer to establish electrical contact between conductive pads of the upper and lower sheets, momentarily closing the circuit. Upon release of force the top sheet springs back to its normal open position. The membrane touch switch is being used in a rapidly expanding range of applications, including instrumentation, appliances, electronic games and keyboards. Its board acceptance results from its low cost, durability, ease of manufacture, cosmetic appeal and design flexibility. The principal electronic components in the membrane switch are the conductor and dielectric.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 241-261
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    Metallization problems with concentrator cells (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Cells used with concentrators have similar contact requirements to other cells, but operation at high intensity imposes more than the usual demands on the metallization. Overall contact requirements are listed and concentrator cell requirements are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 159-169
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    Observations of solar-cell metallization corrosion (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Engineering Sciences Area of the Jet Propulsion Laboratory (JPL) Flat-Plate Solar Array Project is performing long term environmental tests on photovoltaic modules at Wyle Laboratories in Huntsville, Alabama. Some modules have been exposed to 85 C/85% RH and 40 C/93% RH for up to 280 days. Other modules undergoing temperature-only exposures ( 3% RH) at 85 C and 100 C have been tested for more than 180 days. At least two modules of each design type are exposed to each environment - one with, and the other without a 100-mA forward bias. Degradation is both visually observed and electrically monitored. Visual observations of changes in appearance are recorded at each inspection time. Significant visual observations relating to metallization corrosion (and/or metallization-induced corrosion) include discoloration (yellowing and browning) of grid lines, migration of grid line material into the encapsulation (blossoming), the appearance of rainbow-like diffraction patterns on the grid lines, and brown spots on collectors and grid lines. All of these observations were recorded for electrically biased modules in the 280-day tests with humidity.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 137-146
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    Field test experience (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: As a part of the Flat-Plate Solar Array Project (FSA), a field-test program was developed to obtain solar photovoltaic (PV) module performance and endurance data. These data are used to identify the specific characteristics of module designs under various environmental conditions. The information obtained from field testing is useful to all participants in the National Photovoltaics Program, from the research planner to the life-cycle cost analyst.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 59-68
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    Accelerated degradation of silicon metallization systems (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Clemson University has been engaged for the past five years in a program to determine the reliability attributes of solar cells by means of accelerated test procedures. The cells are electrically measured and visually inspected and then subjected for a period of time to stress in excess of that normally encountered in use, and then they are reinspected. Changes are noted and the process repeated. This testing has thus far involved 23 different unencapsulated cell types from 12 different manufacturers, and 10 different encapsulated cell types from 9 different manufacturers. Reliability attributes of metallization systems can be classified as major or minor, depending on the severity of the effects observed. As a result of the accelerated testing conducted under the Clemson program, major effects have been observed related to contact resistance and to mechanical adherence and solderability. This paper does not attempt a generalized survey of accelerated test results, but rather concentrates on one particular attribute of metallization that has been observed to cause electrical degradation - increased contact resistance due to Schottky barrier formation. In this example basic semiconductor theory was able to provide an understanding of the electrical effects observed during accelerated stress testing.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Flat-Plate Solar Array Res. Forum on Photovoltaic Metallization Systems; p 35-57
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    Considerations on the lubrication of spacecraft mechanisms (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Space tribology and a number of precepts to guide designers in its application are discussed. Of the many techniques available all, without exception, have limitations in performance. Two processes are discussed in more detail and their limitations identified. Some performance results on a liquid space lubricant are given.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 19-38
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    Gear Lubrication and Cooling Experiment and Analysis (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A gear tooth temperature analysis was performed using a finite element method combined with a calculated heat input, a calculated oil jet impingement depth, and estimated heat transfer coefficients for the different parts of the gear tooth that are oil cooled and air cooled. Experimental measurements of gear tooth average surface temperature and gear tooth instantaneous surface temperature were made with a fast response, infrared, radiometric microscope. Increasing oil pressure has a significant effect on both average surface temperature and peak surface temperature at loads above 1895 N/cm(1083 lb/in) and speeds of 10,000 and 7500 rpm. Both increasing speed (from 5000 to 10,000 rpm) at constant speed cause a significant rise in the average surface temperature and in the instantaneous peak surface temperatures on the gear teeth. The oil jet pressure required to provide the best cooling for gears is the pressure required to obtain full gear tooth impingement. Calculated results for gear tooth temperatures were close to experimental results for various oil jet impingement depths for identical operating conditions.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 477-490
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    An update on the life analysis of spur gears (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An analytical method for predicting surface fatigue life of gears was presented. General statistical methods were outlined, showing the application of the general methods to a simple gear mesh. Experimentally determined values for constants in the life equation were given. Comparison of the life theory with test results and AGMA standards was made. Gear geometry pertinent to life calculations was reviewed.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 421-434
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    Comparison of spur gear efficiency prediction methods (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The predictions of five spur-gear efficiency calculation methods were compared with three sets of test data using different gear geometries. The data and the analysis methods were limited to jet lubricated, ground, spur gears. The data covered a range in pitch line velocity to 1 to 20 m/sec (200 to 4000 ft/min) and K-load factor range of 17 to 1600.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 365-382
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    Spiral-bevel geometry and gear train precision (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A new aproach to the solution of determination of surface principal curvatures and directions is proposed. Direct relationships between the principal curvatures and directions of the tool surface and those of the principal curvatures and directions of generated gear surface are obtained. The principal curvatures and directions of geartooth surface are obtained without using the complicated equations of these surfaces. A general theory of the train kinematical errors exerted by manufacturing and assembly errors is discussed. Two methods for the determination of the train kinematical errors can be worked out: (1) with aid of a computer, and (2) with a approximate method. Results from noise and vibration measurement conducted on a helicopter transmission are used to illustrate the principals contained in the theory of kinematic errors.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 335-344
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    Evaluation of a high performance, fixed-ratio, traction drive (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A test program was initiated to evaluate the key operational and performance factors associated with the Nasvytis multiroller concept. Two sets of Nasvytis drives, each of slightly geometry, were parametrically tested on a back to back test stand. Initial results from these tests are reported. One of these units was later retrofitted to the power turbine of an automotive gas turbine engine and dynamometer tested.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 271-284
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    Large-bore tapered-roller bearing performance and endurance to 2.4 million DN (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The operating characteristics and experimental life estimates for 120.65 mm bore tapered roller bearings of two designs under combined radial and thrust loads were determined. A modified standard bearing design was tested at speeds up to 15,000 rpm. A computer optimized, high speed design was tested at speeds up to 20,000 rpm. Both designs were tested at a combined load of 26,700 N (6000 lb) radial load and and 53,400 N (12,000 lb) thrust load. Advanced helicopter transmissions which require the higher-speed capability of tapered-roller bearings also require higher temperature capability (ref. 2). Thus, materials with temperature capabilities higher than the conventional carburizing steels are required.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 253-270
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    Lubrication of 35-millimeter-bore ball bearings of several designs to 2.5 million DN (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Parametric tests were conducted with 35mm bore, angular contact ball bearings with either a single or double outer and guided cage. The bearings were either lubricated by oil jets or employed inner ring lubrication. Outer ring cooling was added in selected tests. Lubricant flow to the bearing ranged from 300 to 1900 cc/min. All bearings were successfully run at speeds to 2.5 million DN. Increasing the lubricant flow decreased bearing ring temperatures but increased bearing power lines. The power loss and race temperatures of a jet lubricated with double outer land guided cage were always higher than those of the single land guided design at similar test conditions. The lowest bearing operating temperatures were achieved when inner ring lubrication and outer ring cooling were combined. It is found that cage slip of a double outer land guided cage is approximately twice that of a single outer land guided cage.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 221-238
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    Prediction of ball and roller bearing thermal and kinematic performance by computer analysis (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Characteristics of good computerized analysis software are suggested. These general remarks and an overview of representative software precede a more detailed discussion of load support system analysis program structure. Particular attention is directed at a recent cylindrical roller bearing analysis as an example of the available design tools. Selected software modules are then examined to reveal the detail inherent in contemporary analysis. This leads to a brief section on current design computation which seeks to suggest when and why computerized analysis is warranted. An example concludes the argument offered for such design methodology. Finally, remarks are made concerning needs for model development to address effects which are now considered to be secondary but are anticipated to emerge to primary status in the near future.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 185-202
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    Impact of NASA-sponsored research on aircraft turbine engine bearing specifications (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The advancement of the state-of-the-art in aircraft bearing materials technology is reviewed. Current specifications and design practices resulting from NASA-sponsored programs are included.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 173-184
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    Predicted and experimental performance of large-bore high-speed ball and roller bearings (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The values of inner and outer race temperature, cage speed, and heat transferred to the lubricant or bearing power loss, calculated using the computer programs Shaberth and Cybean, with the corresponding experimental data for the large bore ball and roller bearings were compared. After the development of computer program, it is important that values calculated using such program are compared with actual bearing performance data to assess the programs predictive capability. Several comprehensive computer programs currently in use are capable of predicting rolling bearing operating and performance characteristics. These programs accept input data of bearing internal geometry, bearing material and lubricant properties, and bearing operating conditions. The programs solve several sets of equations that characterize rolling element bearings. The output produced typically consists of rolling element loads and Hertz stresses, operating contact angles, component speed, heat generation, local temperatures, bearing fatigue life, and power loss. Two of these programs, Shaberth and Cybean were developed.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 203-220
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    A historical perspective of traction drives and related technology (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The evolution of traction-drive technology, in a limited sense, is traced from its early development to the efforts underway today.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 79-108
    Format: application/pdf
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  • 87
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    Present technology of rolling-element bearings (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The present technology of rolling-element bearings, the barriers and limits which currently exist, and some of the future requirements that will demand further advancements are identified.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 35-47
    Format: application/pdf
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  • 88
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    Geared power transmission technology (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The historical path of the science and art of gearing is reviewed. The present state of gearing technology is discussed along with examples of some of the NASA-sponsored contributions to gearing technology. Future requirements in gearing are summarized.
    Keywords: MECHANICAL ENGINEERING
    Type: NASA. Lewis Research Center Advanced Power Transmission Technol.; p 49-77
    Format: application/pdf
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  • 89
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    NASA helicopter transmission system technology program (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The purpose of the NASA Helicopter Transmission System Technology Program is to improve specific mechanical components and the technology for combining these into advanced drive systems to make helicopters more viable and cost competitive for commerical applications. The history, goals, and elements of the program are discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: Advanced Power Transmission Technol.; p 15-34
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  • 90
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    Surface topography-connections between lubrication and failure initiation (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The characteristics of the initial surface topography is intimately connected to the machining process by which it is produced. Both processes create a near surface region of residual stresses, microstructure and hardness that is different from the bulk. The material properties in this rather undefined region can significantly influence the mode of failure, such as wear, scuffing or fatigue, as well as the degree of failure resistance for a given material. Under full film elastohydrodynamic (EHD) conditions, where shear is accomodated within a relatively thick lubricant film, the normal and shear stresses are distributed uniformly over the near surface region, and the surface topography has little influence on the lubrication or failure process. Under more typical conditions where surface roughness and lubricant film thickness are of the same order of magnitude, the surface topography not only emerges as an important parameter in failure initiation, but it also becomes intimately involved in the lubrication process itself.
    Keywords: MECHANICAL ENGINEERING
    Type: Delaware Univ. Abstr. of the 20th Ann. Meeting, Society of Engineering Science, Inc.; p 146-147
    Format: text
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  • 91
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    The evolution of a release-engage mechanism for use on the orbiter (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Release-Engage Mechanism (REM) is designed to secure a deployable payload in the orbiter during launch and to enable the payload to be released, deployed, and reattached for re-entry. This paper presents the following: (1) the initial design concepts of the Release-Engage Mechanism; (2) the problems encountered during assembly, (3) the abnormalities that occurred during vibration testing, (4) the incompatibility of the Remote Manipulator System and REM operation, and (5) the resulting modifications to the REM that assured its successful performance on two Shuttle flights.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 357-374
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  • 92
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    A compact magnetic bearing for gimballed momentum wheel (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A three axis controlled magnetic bearing and its application to a momentum wheel are described. The four divided stators provide a momentum wheel with high reliability, low weight, large angular momentum storage capacity, and gimbal control. Those characteristics are desirable for spacecraft attitude control.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 333-342
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  • 93
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    Design of the Galileo remote science pointing actuators (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper describes the two actuators developed for pointing the remote science instruments from the spinning Galileo spacecraft. Details of the key elements are presented together with their design features and developmental difficulties. Four techniques used for power and signal transfer across the actuators' rotating joints are also discussed.
    Keywords: MECHANICAL ENGINEERING
    Type: The 17th Aerospace Mech. Symp.; p 315-332
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  • 94
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    Deployment and release mechanisms on the Swedish satellite, VIKING (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Two mechanism types are presented, a rigid boom system and a 'hold and release' mechanism for spherical sensors. Both mechanisms have been designed, developed and tested by Saab-Space AB, Linkoping, Sweden for the VIKING project under a contract from the Swedish Space Corporation.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 305-314
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  • 95
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    Latch fittings for the scientific instruments on the space telescope (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Latch fittings which kinematically mount the replaceable scientific instruments onto the Space Telescope must maintain precise alignment and thermal stability for on-orbit observations. Design features which are needed to meet stringent criteria include the use of ceramic isolators for thermal and electrical insulation, materials with different coefficients of thermal expansion for athermalization, precision manufacturing procedures, and extremely tight tolerances. A specific latch fitting to be discussed is a ball-and-socket design. In addition, testing, crew aids, and problems will be covered.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 253-265
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  • 96
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    Practical small-scale explosive seam welding (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A small-scale explosive seam welding process has been developed that can significantly contribute to remote metal joining operations under hazardous or inaccessible conditions, such as nuclear reactor repair and assembly of structure in space. This paper describes this explosive seam welding process in terms of joining principles, variables, types of joints created, capabilities, and applications. Very small quantities of explosive in a ribbon configuration are used to create narrow (less than 0.5 inch), long-length, uniform, hermetically sealed joints that exhibit parent metal properties in a wide variety of metals, alloys, and combinations. The practicality of this process has been demonstrated by its current acceptance, as well as its capabilities that are superior in many applications to the universally accepted joining processes, such as mechanical fasteners, fusion and resistance welding, and adhesives.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 227-244
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  • 97
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    Two hundred passage three-way valve: Fraction collector (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper describes the design and operation of a fraction collector used to direct flow of separated biological materials from 197 capillary tubes to either a collection tray or to a waste tank. This mechanism uses a 28-volt dc gear motor driving twin cams to force 197 needles through a self-sealing silicone rubber septum, where they inject the material in 197 separate pockets in a collection tray. The position of the collector tray is sensed by two optical limit switches. The time sequences are controlled automatically by an electronics control monitoring module.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 199-208
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  • 98
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    Securing mechanism for the deployable column of the Hoop/Column antenna (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Column Longeron Latch (CLL) was designed and developed as the securing mechanism for the deployable, telescoping column of the Hoop/Column antenna. The column is an open lattice structure with three longerons as the principal load-bearing members. It is divided into telescoping sections that are deployed after the antenna is place in Earth orbit. The CLL provides a means to automatically lock the longeron sections into position during deployment as well as a means of unlocking the sections when the antenna is to be restowed. The CLL is a four bar linkage mechanism using the over center principle for locking. It utilizes the relative movement of the longeron sections to activate the mechanism during antenna deployment and restowing. The CLL design is one of the first mechanisms developed to meet the restowing requirements of spacecraft which will utilize the STS retrieval capability.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 157-170
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  • 99
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    Space telescope: Solar array primary deployment mechanism (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The requirements, the design, and the test program which were carried out in producing the Space Telescope Solar Array (STSA) primary deployment mechanisms (PDM) are described. The PDM will be used to rotate the rolled solar array supporting boom from its launch position alongside the telescope housing, through 90 deg to its use position. After five years in space the array is to be rerolled and by use of the PDM swung back to its stowed position alongside the telescope housing for capture and return to Earth via the Space Shuttle.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 39-54
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  • 100
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    A broadbased actuator concept for spaceflight application (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An electromechanical actuator is applicable to a variety of spaceflight requirements. Characterized by high torque and a small output step angle, the device is comprised of a coaxial, symmetrical arrangement in which a cup type harmonic drive is directly coupled to a pancake configuration drive motor. The motor, with its dual stator driving a common rotor, is one illustration of the concept of selective redundacy. Selective redundancy promotes the idea that redundancy, to be effective, must not compromise inherent design simplicity nor introduce new failure modes. The usefulness of the actuator is exemplified by its selection for a broad range of positioning and driving applications including TDRSS gimbal drives, Space Telescope deployment and latching machanisms, and Space Telescope secondary mirror drive, as well as others.
    Keywords: MECHANICAL ENGINEERING
    Type: JPL The 17th Aerospace Mech. Symp.; p 55-80
    Format: application/pdf
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