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  • Other Sources  (195)
  • ELECTRONICS AND ELECTRICAL ENGINEERING  (195)
  • 1980-1984  (195)
  • 1950-1954
  • 1925-1929
  • 1983  (195)
  • 1
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    Test methods and results of the 10-cell bipolar Ni-H2 battery (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Characterization tests were carried out at three charge levels and four discharge levels. The "c' or capacity of the battery is designated at 6.5 ampere-hours. The recharge ampere-hours was the same for all test conditions, 6.5 A-H, regardless of the discharge capacity removed for any particular discharge rate. Less capacity can be removed at higher discharge rates to the same termination voltage, which was 0.50 volts for the weakest (lowest voltage) cell. The general trend of efficiencies increases as the charge rate increases as noted in results of the table included in the handout package. The data also indicate the efficiency increases as the discharge rate decreases. This is true; however, efficiencies at the discharge rates of c and 2c are penalized because these cycles received more overcharge than necessary.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 496-500
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  • 2
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    Determination of the reliability of Ni-Cd batteries from survival data on cells fabricated 1964 - 1977 (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The probability of Ni-Cd battery survival was determined by researching survival data on cells fabricated from 1964-1977. A log of cell failure times were plotted against cumulative failure percentage and mean and standard deviation were determined.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 470-479
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  • 3
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    Experimental design (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The design of long life, low weight nickel cadmium cells is studied. The status of a program to optimize nickel electrodes for the best performance is discussed. The pore size of the plaque, the mechanical strength and active material loading are considered in depth.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 253-469
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  • 4
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    Advanced nickel hydrogen cell configuration study (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: An evaluation of the current nickel hydrogen cell design is presented. The IPV, or the Individual Pressure Vessel, is the state of the art right now. The present design, 3 1/2 inch cell, has a current limit of 50 ampere-hours. The nickel hydrogen cell design is the state of the art. Its size is 3 1/2 inches which limits it to 50 hours. The probable limits of that are probably 160 amphere IPV cell remaining in the passive cooling mode. The IPV stacks is a parallel connection of electrodes. Positive electrodes are connected with leads to the top portion of the stack and negative electrodes are connected with leads and pulled down to the bottom. So it is a combination connection of paralleling series electrostacking--parallel inside each individual stack, and series connected from one stack to the next. It offers, in the analysis, improvements in packaging, cost, energy density, and specific energy.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 480-495
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  • 5
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    Nickel hydrogen/nickel cadmium battery trade studies (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Nickel Hydrogen cell and battery technology has matured to the point where a real choice exists between Nickel Hydrogen and Nickel Cadmium batteries for each new spacecraft application. During the past few years, a number of spacecraft programs have been evaluated at Hughes with respect to this choice, with the results being split about fifty-fifty. The following paragraphs contain criteria which were used in making the battery selection.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 430-438
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  • 6
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    Canadian experience with nickel cadmium systems (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The Defense Research Establishment Ottawa (DREO) has been studying the nickel-cadmium system, both vented and sealed, since the early 1950's. Reasonable success has been achieved in a wide variety of applications covering: military vehicle use under Arctic conditions; high performance military aircraft; manpacked communications sets; remote standby power and small portable instrumentation. Early studies on the vented system for high rate vehicle and aircraft cranking applications proved useful in later studies on the sealed NiCd system. This was especially true in the areas of plate loading and electrolyte composition. To achieve high rate cranking currents of 20C to 30C, it was necessary to have light to moderate plate loadings, a large reactive surface area, and electrolyte of optimum conductivity. DREO undertook some fundamental studies to understand the system from the inside out rather than test cells from the outside and then analyze their components. The conclusions of these studies were incorporated into the Procurement Specification for Ni-Cd cells ISISA Spec S615-P-2. A brief comment will be made on the choice of cell design and how some of the factors of cell manufacture could affect cell performance.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 439-451
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  • 7
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    Real and potential nickel hydrogen superiority (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Events from the development and orbital flight experience with a nickel hydrogen battery are described. The events highlight characteristics of nickel hydrogen which afford superior capability in overcharge, overdischarge and state of charge evaluation, when compared to the nickel cadmium electrochemical system. Some developments in nickel hydrogen technology that provide the potential of furthering nickel hydrogen superiority for satellite applications are also discussed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 416-429
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  • 8
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    Ni-H2 batteries for communications satellites (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Ni-H2 batteries are just now being put into service. All of the remaining INTELSAT V satellites (approximately 10), starting with the next to be launched in early 1983, will use Ni-H2 batteries. In addition, the next generation of INTELSAT VI satellites, and probably INTELSAT VII and VIII, will use Ni-H2 batteries. This means that international telecommunications satellites will use Ni-H2 batteries through the 1990's. It is projected that the lifetime of these batteries will be greater than 10 years at deep depth-of-discharge (DOD), and that the battery subsystem will no longer limit satellite lifetime or communications capability during eclipse periods. This paper discusses the advantages of the Ni-H2 battery, as compared with the Ni-Cd battery, for telecommunications satellites.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 389-415
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  • 9
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    Status of SAFT silver hydrogen cell development (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Nickel-hydrogen cells appear to be an improvement over the nickel-cadmium in applications requiring longer lifetime and reduced weight. An even more efficient couple, the silver-hydrogen couple, is also considered. After a theoretical study first performed by the Battelle Institute of Geneva under ESA (European Space Agency) contract, SAFT has undertaken more detailed analyses of the silver-hydrogen degradation mechanisms. ESA and the French Department of Defense contracted with SAFT for a full-development program of the silver-hydrogen technology.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 347-371
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  • 10
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    Reconditioning and the nickel electrode (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: This effects of reconditioning on the performance of NiCd batteries are reviewed. These effects are correlated with cell experiments and individual electrode investigations. The effects of reconditioning on the positive electrode performance are found to be significant. A mechanism is proposed that rationalizes the operation of the nickel electrode and suggests that reconditioning minimizes depth of discharge stress during use and maintains uniformity of the active material.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 324-345
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  • 11
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    Spacecraft battery reconditioning cost considerations (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Cost considerations for spacecraft battery reconditioning are studied. Results indicate that the cost of performing reconditioning is minuscule compared with spacecraft system investment. Results also indicate that spacecraft life extension of a few days justifies incorporation of reconditioning circuitry.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 303-310
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  • 12
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    Unique battery reconditioning cycle for RCA's geostationary satellites and its applicability for low Earth satellite (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Six (6) geostationary spacecraft, manufactured by RCA Astro, are presently operating in orbit. All of their batteries are performing well. They all contain unique battery reconditioning circuitry, permitting individual cell reconditioning to practically zero volts without the danger of cell reversal. This reconditioning is performed just prior to start of each eclipse season. This technique has maintained the battery's end-of-discharge voltage with mission life. The oldest operating RCA Astro geostationary spacecraft, Satcom F1 and F2, have now completed almost 7 and 6-3/4 years in orbit, respectively. Their battery performance, reported herein, show that a major milestone in the mission longevity of nickel-cadmium batteries has heen achieved. Low earth orbit test data show a long lasting effect of maintaining end-of-discharge voltages for nickel cadmium cells using periodic reconditioning. The unique RCA light-weight reconditioning circuitry can accomplish a quick reconditioning and prevent cell reversal. Reconditioning, thus, has the potential for extending mission life of geostationary as well as low earth orbit spacecraft, when two or more batteries are present.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 311-323
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  • 13
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    Deep discharge reconditioning: Pros and cons (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Deep-discharge reconditioning (DDR) can be of great benefit to battery performance, especially in geosynchronous orbit, if performed properly and regularly, and can be essential to operation of batteries at the high depths of discharge (DOD) required to minimize weight. The procedure should be tailored to fit the nature of the degradation occuring during regular cycling. DDR is not without its drawbacks, however, and these differ depending on the normal DOD to be sustained and/or whether the discharge is done at the battery or the cell level. Battery-level discharge carries the minimum weight penalty but raises questions of the effects of low-rate cell reversal that as yet have no firm answers. Cell level discharge avoids cell reversal but carries significant penalties of weight and complexity. Thus no universal procedure or method of implementation of deep-discharge reconditioning is now available and thus the various approaches must be evaluated for each application.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 297-302
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  • 14
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    Control requirements for future battery systems (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: It is argued that sophisticated battery control systems are required to support the high power, high energy spacecraft secondary battery systems of the post 1985 time period. Four categories of battery control system functions are defined and discussed: battery operational control, auxiliary system control, battery system status indication and fault detection fault isolation. A concept for implementation of such a control system is also presented and discussed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 270-279
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  • 15
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    A comparison of voltage limit charge control for fixed array and sun oriented array missions (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A comparison of voltage limited control methods limit control methods for fixed array and oriented array missions is given. The LANDSAT D, Earth Radiation Budget Experiment and Solar maximum Mission techniques are compared.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The 1982 Goddard Space Flight Center Battery Workshop; p 231-258
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  • 16
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    Battery charge control with temperature compensated voltage limit (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Battery charge control for orbiting spacecraft with mission durations from three to ten years, is a critical design feature that is discussed. Starting in 1974, the General Electric Space Systems Division designed, manufactured and tested battery systems for six different space programs. Three of these are geosynchronous missions, two are medium altitude missions and one is a near-earth mission. All six power subsystems contain nickel cadmium batteries which are charged using a temperature compensated voltage limit. This charging method was found to be successful in extending the life of nickel cadmium batteries in all three types of earth orbits. Test data and flight data are presented for each type of orbit.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 259-269
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  • 17
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    Computer modeling of batteries from non-linear circuit elements (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A simple non-linear circuit model for battery behavior is given. It is based on time-dependent features of the well-known PIN change storage diode, whose behavior is described by equations similar to those associated with electrochemical cells. The circuit simulation computer program ADVICE was used to predict non-linear response from a topological description of the battery analog built from advice components. By a reasonable choice of one set of parameters, the circuit accurately simulates a wide spectrum of measured non-linear battery responses to within a few millivolts.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 201-215
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  • 18
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    Modeling a Li/SOCl2 battery for design purposes (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A generalized code applicable to many different electrochemical systems and geometric designs is discussed. The code is to be set up so that physical property data such as thermal conductivity, viscosity, density, and configuration (e.g. physical dimensions) are the input data. Thus, by changing these parameters many different battery configurations can be handled. The outputs, as a function of time and space, are voltage, current, temperature, pressure, velocity, and species concentration.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 178-199
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  • 19
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    Fitting voltage curves with an electrochemically derived equation (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Previous work is refined and extended to describe the discharge curve of Ni-Cd cells. Several models are discussed which are based on chronopotentiometry theory and on a thermodynamic approach. Emphasis is placed on improvement of the fit for the initial portion of discharge. Equations are presented which improve the fit for all regions of the discharge curve.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 164-177
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  • 20
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    Battery model for electrical power system energy balance (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A model to simulate nickel-cadmium battery performance and response in a spacecraft electrical power system energy balance calculation was developed. The voltage of the battery is given as a function of temperature, operating depth-of-charge (DOD), and battery state-of-charge. Also accounted for is charge inefficiency. A battery is modeled by analysis of the results of a multiparameter battery cycling test at various temperatures and DOD's.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 117-124
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  • 21
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    Validating cell/battery safety (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Using the accelerating rate calorimeter, the hazards associated with exothermic reactions occurring in Li/SO2 cells under the conditions of discharge, forced overdischarge, resistive overdischarge, and forced overdischarge at low tempratures are quantitatively defined in terms of: rate of pressure generation, overall pressure rise, rate of temperature, and overall heat generation. Consistent with the findings of other investigators, it is believed that the major reactions contributing to Li/SO2 cell exothermicity are: the lithium/acetonitrile reaction, the thermal decomposition of lithium dithionite, and the lithium/sulfur reaction.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 85-99
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  • 22
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    Design of a safe cylindrical lithium/thionyl chloride cell (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Cell design criteria were established which can result in a safe lithium/thionyl chloride cell. A cell vent, a low area internal anode cell, cell balance and composition of the cathode-electrolyte solution were found to be important factors in the design of a safe cell. In addition to routine testing, both undischarged and discharged cells were subjected to electrical abuse, environmental abuse and mechanical abuse without disassembly.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 75-84
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  • 23
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    Controlling hazardous reactions during voltage reversal of high energy lithium cells (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The roll of general cell design characteristics in preventing hazardous reactions during voltage reversal of lithium cells is discussed. Anode limited versus cathode limited design and case positive versus case negative design are addressed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 67-74
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  • 24
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    Safety tests (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The ovedischarge test program and results for double A and D lithium cells are discussed. Temperature increases and sparking responses are dressed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 60-63
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  • 25
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    Low temperature performance tests (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Lithium cell performance at extremely low temperatures was tested and materials which could be used to make a cell completely electro-chemically inert for the purpose of deactivation were investigated. The effects of temperature and current density on polarization and performance loss are discussed along with discharge recovery behavior.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 64-66
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  • 26
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    Policies governing the use of lithium batteries in the Navy (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Lithium batteries offer many advantages for Navy systems but may also exhibit undesirable hazardous behavior. Safety problems have been traced to a variety of chemical and physical causes. The Navy has established a central safety office with responsibility for all lithium battery use. Before an item is approved for Navy use, it must pass both a design review and a set of end item tests. These reviews focus on complete systems which include a battery inside the end item. After system approval, specific regulations govern the transportation, storage, and disposal of the unit containing lithium batteries. Each of these areas is discussed in detail.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 23-34
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  • 27
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    The Galileo probe Li/SO2 battery: The safest battery on Jupiter (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The unique power requirement of NASA's Galileo Jupiter Probe are most readily met by a Li/SO2 battery; however, because this battery system is not space flight proven, extensive effort was required to qualify this device from the stand point of performance and safety. Due to the rather checkered safety record of the Li/SO2 system, safety has been foremost among the design considerations and has been addressed at the cell, battery and system level. The mission requirements which led to the choice of the Li/SO2 battery and the safety engineering which went into the battery and power system design are described.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 15-22
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  • 28
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    forced overdischarge related safety aspects of Li/SO2 and Li/SOCl2 cells (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Results of an experiment investigating overdischarge behavior of two types of Li/SO2 cells are presented. Forced overdischarges of the Li/LiBr, CH3CN/SO2 cell can result in unsafe behavior such as venting with fire and release of toxic gases. The hazards may be minimized or eliminated by careful cell design considerations and practice of high standards of quality contol in cell manufacture. Seemingly safe cells at 25 C when forced overdischarged at -25 C, even at low currents, exhibited incipient signs of hazards. Their cathodes indicated signs of shock sensitivity. Cathode limited Li/SOCl2 cells were safe during forced overdischarge for long periods of time. Lithium limited Li/SOCl2 cells in which practically all Li had been used up before cell reversal did not exhibit hazardous behavior. Anode limited Li/SOCl2 cells, but not Li limited, exhibited detonations, all during overdischarges at relatively low current densities of or = 1 mA/sq cm 2. Anode potentials 4v with large oscillations preceeded the events. The events were confined to the anode and the temperature rose high enough to melt Ni grids.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 47-59
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  • 29
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    Primary lithium batteries, some consumer considerations (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: In order to determine whether larger size lithium batteries would be commercially marketable, the performance of several D size lithium batteries was compared with that of an equivalent alkaline manganese battery, and the relative costs of the different systems were compared. It is concluded that opportunities exist in the consumer market for the larger sizes of the low rate and moderate rate lithium batteries, and that the high rate lithium batteries need further improvements before they can be recommended for consumer applications.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 35-45
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  • 30
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    Hazardous behavior of lithium batteries. Case histories (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Case histories were described of hazardous behavior for three different cell sizes ranging in nominal capacity from 300 mAh to 12,000 Ah. Design characteristics and other facts believed to have been responsible for the cell explosions, are presented. Obvious facts are discussed as causes for hazardous behavior of lithium batteries in general and oxyhalide batteries in particular.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 3-14
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  • 31
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    Modeling battery life through changes in voltage fit coefficients (1983)
    In:  CASI
    Details
    Publication Date: 2006-10-01
    Description: A number of 12 ampere-hour cells, nickel cadmium, were cycled under various conditions of temperature and depth of discharge. Using this data, it was confirmed that a five parameter fit equation could be used to model the data within a few millivolts. Both charge and discharge curves can be fit with accuracies in the range of one or two millivolts. The fit coefficients when plotted versus cycles show definite trends and patterns which can be used in an operational sense to predict battery voltage as a function of temperature and depth of discharge.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center The 1982 Goddard Space Flight Center Battery Workshop; p 125-163
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  • 32
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    New cryogenic P-channel metal-oxide-semiconductor field effect transistor (MOSFET) with optimized doping yielding performance superior to the G-118, W-164, and 3N165 at 77 K, 4 K, and 1.8 K (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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    Modeling of single-event upset in bipolar integrated circuits (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The results of work done on the quantitative characterization of single-event upset (SEU) in bipolar random-access memories (RAMs) have been obtained through computer simulation of SEU in RAM cells that contain circuit models for bipolar transistors. The models include current generators that emulate the charge collected from ion tracks. The computer simulation results are compared with test data obtained from a RAM in a bipolar microprocessor chip. This methodology is applicable to other bipolar integrated circuit constructions in addition to RAM cells.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-30; 4540-454
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    The damage equivalence of electrons, protons, alphas and gamma rays in rad-hard MOS devices (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper reports on a study of damage equivalence in rad-hard MOS devices with 100,000 rads (SiO2) capability. Damage sensitivities for electrons of 1, 2, 3, 5, and 7 MeV, protons of 1, 3, 7, 22, and 40 MeV, 3.4-MeV alphas, and Co-60 gammas were measured and compared. Results indicated that qualitatively the same charge recombination effects occurred in hard oxide devices for doses of 100,000 rads (SiO2) as in soft oxide parts for doses of 1 to 4 krads (SiO2). Consequently, damage equivalency or non-equivalency depended on radiation type and energy. However, recovery effects, both during and after irradiation, controlled relative damage sensitivity and its dependency on total dose, dose rate, supply bias, gate bias, radiation type, and energy. Correction factors can be derived from these data or from similar tests of other hard oxide type, so as to properly evaluate the combined effects of the total space environment.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-30; 4363-436
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    Evaluation of the emission capabilities of Spindt-type field emitting cathodes (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The electron emitting capabilities of Spindt-type field emitting cathodes (FEC) are being studied at the Lewis Research Center, NASA. These cathodes, having 5000 emitting points in a 1 mm diameter, have been shown to be capable of emission current densities of 10 A/sq cm and higher. The purposes of this study are to (1) demonstrate that the cathodes can be processed and used in a tube-type configuration, (2) determine whether, at a sufficiently high current density, the cathode can operate in the space charge mode, and (3) evaluate failure mechanisms in this unique type of electron emitter. FEC's have been tested in a diode configuration, by the use of pulse techniques, up to current densities of 6 A/sq cm and anode potentials of 3000 V. Space charge effects have been observed in the range of 5 A/sq cm as an apparent linear increase of cathode current with anode voltage for a constant emitter-gate potential. Failed cathodes were studied by means of scanning electron microscopy and the major failure modes encountered are attributed to gas evolution, followed by arcing, which destroys either individual emitters or a large segment of the cathode area.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applications of Surface Science (ISSN 0378-5963); 16; 277-291
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  • 36
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    An improved push-pull voltage fed converter using a tapped output-filter inductor (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A new concept of using a tapped output-filter inductor and an auxiliary commutating diode to reduce the likelihood of transformer core saturation in a push-pull, voltage-fed converter is presented. The linearized circuit model and transfer functions are derived with a hybrid approach using both state-space and circuit averaging. Operation of the new converter - including parasitic effects - is discussed, and a design equation for inductor tap ratio is established. It is predicted and experimentally confirmed that the new converter has more symmetrical transformer core operation, and the potential exits for lower transistor turnon current and reduced transistor voltage stress. These benefits reduce switching loss and enhance transistor reliability.
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  • 37
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    Low-noise 115-GHz receiver using superconducting tunnel junctions (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A 110-118-GHz receiver based on a superconducting quasiparticle tunnel junction mixer is described. The single-sideband noise temperature is as low as 68 + or - 3 K. This is nearly twice the sensitivity of any other receiver at this frequency. The receiver was designed using a low-frequency scale model in conjunction with the quantum mixer theory. A scaled version of the receiver for operation at 46 GHz has a single-sideband noise temperature of 55 K. The factors leading to the success of this design are discussed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Physics Letters (ISSN 0003-6951); 43; 786-788
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  • 38
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    New propulsion components for electric vehicles (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Improved component technology is described. This includes electronically commutated permanent magnet motors of both drum and disk configurations, an unconventional brush commutated motor, ac induction motors, various controllers, transmissions and complete systems. One or more of these approaches to electric vehicle propulsion may eventually displace presently used controllers and brush commutated dc motors. Previously announced in STAR as N83-25982
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    Annual Conference on Nuclear and Space Radiation Effects, Gatlinburg, TN, July 18-21, 1983, Proceedings (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Topics discussed include radiation effects in devices; the basic mechanisms of radiation effects in structures and materials; radiation effects in integrated circuits; spacecraft charging and space radiation effects; hardness assurance for devices and systems; and radiation transport, energy deposition and charge collection. Papers are presented on the mechanisms of small instabilities in irradiated MOS transistors, on the radiation effects on oxynitride gate dielectrics, on the discharge characteristics of a simulated solar cell array, and on latchup in CMOS devices from heavy ions. Attention is also given to proton upsets in orbit, to the modeling of single-event upset in bipolar integrated circuits, to high-resolution studies of the electrical breakdown of soil, and to a finite-difference solution of Maxwell's equations in generalized nonorthogonal coordinates.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: (ISSN 0018-9499)
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  • 40
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    Single event upset (SEU) of semiconductor devices - A summary of JPL test data (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The data summarized describe single event upset (bit-flips) for 60 device types having data storage elements. The data are from 15 acceleration tests with both protons and heavier ions. Tables are included summarizing the upset threshold data and listing the devices tested for heavy ion induced bit-flip and the devices tested with protons. With regard to the proton data, it is noted that the data are often limited to one proton energy, since the tests were usually motivated by the engineering requirement of comparing similar candidate devices for a system. It is noted that many of the devices exhibited no upset for the given test conditions (the maximum fluence and the maximum proton energy Ep are given for these cases). It is believed, however, that some possibility of upset usually exists because there is a slight chance that the recoil atom may receive up to 10 to 20 MeV of recoil energy (with more energy at higher Ep).
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-30; 4520-452
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  • 41
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    Recovery of damage in rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper reports on the recovery properties of rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays. The results indicated that complex recovery properties controlled the damage sensitivities of the tested parts. The results also indicated that damage sensitivities depended on dose rate, total dose, supply bias, gate bias, transistor type, radiation source, and particle energy. The complex nature of these dependencies make interpretation of LSI device performance in space (exposure to entire electron and proton spectra) difficult, if not impossible, without respective ground tests and analyses. Complete recovery of n-channel shifts was observed, in some cases within hours after irradiation, with equilibrium values of threshold voltages greater than their pre-irradiation values. This effect depended on total dose, radiation source, and gate bias during exposure. In contrast, the p-channel shifts recovered only 20 percent within 30 days after irradiation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-30; 4157-416
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  • 42
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    Distributed control of large space antennas (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A systematic way to choose control design parameters and to evaluate performance for large space antennas is presented. The structural dynamics and control properties for a Hoop and Column Antenna and a Wrap-Rib Antenna are characterized. Some results of the effects of model parameter uncertainties to the stability, surface accuracy, and pointing errors are presented. Critical dynamics and control problems for these antenna configurations are identified and potential solutions are discussed. It was concluded that structural uncertainties and model error can cause serious performance deterioration and can even destabilize the controllers. For the hoop and column antenna, large hoop and long meat and the lack of stiffness between the two substructures result in low structural frequencies. Performance can be improved if this design can be strengthened. The two-site control system is more robust than either single-site control systems for the hoop and column antenna.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 225-247
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  • 43
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    Semiconductor optoelectronic devices for free-space optical communications (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The properties of individual injection lasers are reviewed, and devices of greater complexity are described. These either include or are relevant to monolithic integration configurations of the lasers with their electronic driving circuitry, power combining methods of semiconductor lasers, and electronic methods of steering the radiation patterns of semiconductor lasers and laser arrays. The potential of AlGaAs laser technology for free-space optical communications systems is demonstrated. These solid-state components, which can generate and modulate light, combine the power of a number of sources and perform at least part of the beam pointing functions. Methods are proposed for overcoming the main drawback of semiconductor lasers, that is, their inability to emit the needed amount of optical power in a single-mode operation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Communications Magazine (ISSN 0163-6804); 21; Sept
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  • 44
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    A 20-GHz IMPATT transmitter, summary (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A three stage IMPATT diode amplifier capable of a 16 W CW output and a 2 dB bandwidth of 117 MHz was developed. On the component side, high performance circulators with a 0.2 dB insertion loss and bandwidth of 5 GHz were fabricated. State of the art GaAs IMPATT diodes incorporating diamond heat sink and double Read doping profile were also developed. The diodes are capable of a 2.5 W CW output. A few diodes achieved power outputs as high as 3 W. On the circuit side, high gain (up to 12 dB per stage) single diode, multituned circuits capable of 2 GHz and 930 MHx bandwidth were developed as the first and second stages, respectively, of the amplifier. A 12 diode waveguide cavity combiner was developed as the output stage. The output stage utilized commercially available single drift GaAs IMPATT diodes.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: A 20-GHz IMPATT Tansmitter 1; 126 p
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  • 45
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    Radiation effects on MOS devices - dosimetry, annealing, irradiation sequence, and sources (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper reports on some investigations of dosimetry, annealing, irradiation sequences, and radioactive sources, involved in the determination of radiation effects on MOS devices. Results show that agreement in the experimental and theoretical surface to average doses support the use of thermo-luminescent dosimeters (manganese activated calcium fluoride) in specifying the surface dose delivered to thin gate insulators of MOS devices. Annealing measurements indicate the existence of at least two energy levels,,s or a activation energies, for recovery of soft oxide MOS devices after irradiation by electrons, protons, and gammas. Damage sensitivities of MOS devices were found to be independent of combinations and sequences of radiation type or energies. Comparison of various gamma sources indicated a small dependence of damage sensitivity on the Cobalt facility, but a more significant dependence in the case of the Cesium source. These results were attributed to differences in the spectral content of the several sources.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-30; June 198
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  • 46
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    Tubes in space - Very much alive (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Some advantages of TWTs over SSDs are discussed. Wideband TWTs have been developed which can produce 20 W of RF power at 20 GHz with 40 percent efficiency, a figure three or four times that available from SSDs such as FETs. The basic performance of TWTs exceeds that of SSDs for any given bandwidth and frequency. SSDs are transit time limited, and their performance deteriorates fundamentally as the reciprocal of the square of the operating frequency. Power limits for SSDs have been reached or are quickly being approached. Free electron devices such as tubes have an efficiency advantage because electrons in the vacuum travel faster than bulk charges in SSDs. Combined SSD devices are prone to burnout and incur penalties due to the need to dissipate heat. TWTs have a 6.7:1 advantage in radiator area ratio. Recent progress in TWT technology has produced a tenfold increase in CW output power, doubled to quadrupled the efficiency, and pushed frequency ranges into the terahertz region, orders of magnitude beyond the SSD cutoff.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Microwaves & RF; 22; Mar. 198
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  • 47
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    Receivers (1983)
    In:  CASI
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    Publication Date: 2014-09-11
    Description: Before discussing Deep Space Network receivers, a brief description of the functions of receivers and how they interface with other elements of the Network is presented. Different types of receivers are used in the Network for various purposes. The principal receiver type is used for telemetry and tracking. This receiver provides the capability, with other elements of the Network, to track the space probe utilizing Doppler and range measurements, and to receive telemetry, including both scientific data from the onboard experiments and engineering data pertaining to the health of the probe. Another type of receiver is used for radio science applications. This receiver measures phase perturbations on the carrier signal to obtain information on the composition of solar and planetary atmospheres and interplanetary space. A third type of receiver utilizes very long baseline interferometry (VLBI) techniques for both radio science and spacecraft navigation data. Only the telemetry receiver is described in detail in this document. The integration of the Receiver-Exciter subsystem with other portions of the Deep Space Network is described.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Deep Space Network: A Radio Commun. Instr. for Deep Space Exploration; 26 p
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  • 48
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    Low Noise Amplifiers (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-11
    Description: One of the great technical challenges facing the Deep Space Network is receiving signals from a severely weight limited spacecraft hundreds of thousands to billions of kilometers from Earth. This weight limitation has always imposed strict limitations on the size of the spacecraft antenna and the amount of transmitter power radiated. The communication burden is placed upon the ground systems of the Deep Space Network which must recover an extremely weak signal in the presence of nearly overwhelming amounts of noise. Two key parameters that determine the signal to noise ratio of a received signal using a deep space station are the collecting area and efficiency of the antenna, and the amount of noise which is generated in, as well as allowed to enter in, the antenna-mounted receiver. These parameters are used to describe the relative ability of a deep space station to receive weak signals. As spacecraft to Earth communication distances have increased, the Deep Space Network engages in a relentless effort to increase the figure of merit through larger and more efficient antennas, higher frequencies, and lower system noise temperature.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Deep Space Network: A Radio Commun. Instr. for Deep Space Exploration; 32 p
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  • 49
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    SAR Speckle Noise Reduction Using Wiener Filter (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-10
    Description: Synthetic aperture radar (SAR) images are degraded by speckle. A multiplicative speckle noise model for SAR images is presented. Using this model, a Wiener filter is derived by minimizing the mean-squared error using the known speckle statistics. Implementation of the Wiener filter is discussed and experimental results are presented. Finally, possible improvements to this method are explored.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Texas A and M Univ. Proc. of the NASA Symp. on Math. Pattern Recognition and Image Analysis; p 295-310
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  • 50
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    Approximation to the Probability Density at the Output of a Photmultiplier Tube (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-10
    Description: The probability density of the integrated output of a photomultiplier tube (PMT) is approximated by the Gaussian, Rayleigh, and Gamma probability densities. The accuracy of the approximations depends on the signal energy alpha: the Gamma distribution is accurate for all alpha, the Raleigh distribution is accurate for small alpha (approximate or less than 1 photon) and the Gaussian distribution is accurate for large alpha (approximate or greater than 10 photons).
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommun. and Data Acquisition Rept.; p 36-39
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  • 51
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    Qualification testing for a central station (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Qualification testing for a Central Station Photovoltaic (PV) Facility depends to a great extent on the system design, (fixed versus tracking), and the level of data acquisition/control which is incorporated into the system. The basic elements which require qualification tests include: dc power production/collection; tracker conversion systems; ac utility interface; system level control; and data acquisition/reporting. The qualification tests from the Lungo (ARCO) 1 MW Facility which were completed in January 1983 are discussed. The philosophy and many of the procedures are applicable to any central station PV facility.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 283-299
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    Qualification testing and electrical measurement experience: A manufacturer's view (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: ARCO Solar's experiences as a participant in an industry-utility-government environmental qualification team examining photovoltaic devices are discussed. Included is an assessment of the applicability, completeness and appropriateness of the testing procedures and of the acceptance criteria for megawatt-sized procurements for utilities. Like the stand-alone users, the utility industry is interested in obtaining low costs, but additional concerns exist related to reliability and durability, safety, grounding and overall system criteria including performance prediction (related to output power acceptance testing), power quality and dispatchability. For purposes of this first major purchase of photovoltaic modules and panels by the utility industry, there was a carry-over of the JPL specifications. The need exists for futher development, assessement, and selection of qualification and testing standards and evaluation criteria specifically addressing these additional concerns for utility-connected PV power-plant applications.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 277-281
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  • 53
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    Qualification and testing of modules (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The experience gained in procuring solar modules soon to be installed on the Photovoltaic Higher Education National Exemplar Facility (PHENEF) at Georgetown University is discussed. The 300 KE Photovoltaic Array consists of 4464, 2' X 4', polycrystalline solar cell modules. The performance requirements for the modules are described in a detailed procurement specification which defines physical and electrical characteristics and extensive quality assurance provisions including requirements for an interface control drawing and qualification and acceptance testing.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 265-276
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  • 54
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    Qualification tests and electrical measurements: Practice and problems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: As part of the Flat-Plate Solar Array Project, 138 different module designs were subjected to qualification tests. Electrical measurements were subjected on well over a thousand modules representing more than 150 designs. From this experience, conclusions are drawn regarding results and problems, with discussion of the need for change or improvement. The qualification test sequence incuded application of environmental and electrical stresses to the module. With few exceptions, the tests have revealed defects necessitation of environmental and electrical stresses to the module. With few exceptions, the tests have revealed defects necessitating module design or process changes. However, the continued need for these tests may be questioned on the basis of technical and logistical factors. Technically, the current test sequence does not cover all design characteristics, does not include all field conditions and is not known to represent the desired 30-year module life. Logistically, the tests are time-consuming and costly, and there is a lack of, fully qualified independent test organizations. Alternatives to the current test program include simplification based on design specification and site environment, and/or the use of warranties or other commercial practices.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 257-264
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    Is structural interface standardization beneficial? (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Factors applicable to fixed angle, large field and fixed angle, large building flat plate photovoltaic (PV) generator arrays are discussed in the context of standardization. It is concluded that structural interface standardization may be highly desirable in any one major project, but not at this time in the overall PV industry. Attempts to mandate such standardization will act as a deterrent to long-range improvements. In specific projects, structural standardization should be defined at the largest practical interface, leaving the maximum possible freedom to the module and array manufacturer. There is a corollary area, however, where detailed standards would benefit the industry; the matter of Standard Practices. Work being done towards definition of acceptable/desirable practices in materials, finishes, fastening and locking methods, grounding techniques, lightning protection, etc., and in handling the environmental ranges, should be continued.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 235-245
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    Interface standardization (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Central-station applications create a large and attractive market for photovoltaics in the near future. However, some significant barriers lie between the industry of today and realization of that market. Manufacturing capacity and price are two principal impediments. The Utilities, which are the future system owners, are gaining experience with central-station PV power through the Sacramento Municipal Utility District, Hesperia and similar small central-station installations. SMUD has recognized that competition must be maintained to help reduce prices. So little standardization exists that the cost is driven upward to redefine mechanical and electrical interfaces for each vendor. New structues are required for each vendor and nonoptimum field geometries result from attempts to include more than one vendor in an array field. Standards at some hardware level are required.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 221-225
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  • 57
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    Evolution of integrated panel structural design and interfaces for PV power plants (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The evolution of integrated photovoltaic (PV) panel design at ARCO Solar is discussed. Historically, framed PV modules of about 1 x 4-ft size were individually mounted in the field on fixed support structures and interconnected electrically with cables to build higher-power arrays. When ARCO Solar saw the opportunity in 1982 to marry its PV modules with state-of-the-art heliostat trackers developed by ARCO Power Systems, it became obvious that mounting individual modules was impractical. For this project, the framed modules were factory-assembled into panels and interconnected with cables before being mounted on the trackers. Since then, ARCO Solar made considerable progress and gained substantial experience in the design and fabrication of large PV panels. Constraints and criteria considered in these design activities included static and dynamic loads; assembly and transportation equipment and logistics, structural and electrical interfaces, and safety and grounding concerns.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 227-233
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    Photovoltaic central station step and touch potential considerations in grounding system design (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The probability of hazardous step and touch potentials is an important consideration in central station grounding system design. Steam turbine generating station grounding system design is based on accepted industry practices and there is extensive in-service experience with these grounding systems. A photovoltaic (PV) central station is a relatively new concept and there is limited experience with PV station grounding systems. The operation and physical configuration of a PV central station is very different from a steam electric station. A PV station bears some similarity to a substation and the PV station step and touch potentials might be addressed as they are in substation design. However, the PV central station is a generating station and it is appropriate to examine the effect that the differences and similarities of the two types of generating stations have on step and touch potential considerations.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 205-215
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  • 59
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    Grounding and fault protection of the SMUD PVI array (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: If large terrestrial photovoltaic (PV) power plants are to provide an economic source of generation, low-cost, reliable and easily maintainable systems must be developed. In addition, if the system is to be a central station powerplant owned and operated by an electric utility, the design must also be consistent with utility specifications and design standards. The particular solutions developed to address these issues, with regard to grounding and fault protection, for the first phase of the Sacramento Municipal Utility District's (SMUD) 100 mw(ac) PV powerplant are presented. This plant, known as PV1, is nominally rated at 1 mw(ac) and is scheduled to be in operation by the spring of 1984.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 197-203
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  • 60
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    Electrical safety for high voltage arrays (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A number of key electrical safety requirements for the high voltage arrays of central station photovoltaic power systems are explored. The suitability of representative industrial DC power switchgear for control and fault protection was evaluated. Included were AC/DC circuit breakers, electromechanical contactors and relays, load interruptors, cold disconnect devices, sectionalizing switches, and high voltage DC fuses. As appropriate, steady state and transient characteristics were analyzed. Failure modes impacting upon operation and maintenance safety were also identified, as were the voltage withstand and current interruption levels.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 187-196
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  • 61
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    Photovoltaic system grounding and fault protection (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The grounding and fault protection aspects of large photovoltaic power systems are studied. Broadly, the overlapping functions of these two plant subsystems include providing for the safety of personnel and equipment. Grounding subsystem design is generaly governed by considerations of personnel safety and the limiting of hazardous voltages to which they are exposed during the occurrence of a fault or other misoperation of equipment. A ground system is designed to provide a safe path for fault currents. Metal portions of the modules, array structures, and array foundations are used as a part of the ground system, provided that they and their interconnection are designed to be suitably reliable over the life of the plant. Several alternative types of fault protection and detection equipment are designed into the source circuits and dc buses feeding the input terminals of the subfield power conditioner. This design process requires evaluation of plausible faults, equipment, and remedial actions planned to correct faults. The evaluation should also consider life cycle cost impacts.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 181-186
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  • 62
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    Breakdown of organic insulators (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Solar cells and their associated electrical interconnects and leads were encapsulated in transparent elastomeric materials. Their purpose in a photovoltaic module, one of the most important for these elastomeric encapsulation materials, is to function as electrical insulation. This includes internal insulation between adjacent solar cells, between other encapsulated electrical parts, and between the total internal electrical circuitry and external metal frames, grounded areas, and module surfaces. Catastrophic electrical breakdown of the encapsulant insulation materials or electrical current through these materials or module edges to external locations can lead to module failure and can create hazards to humans. Electrical insulation stability, advanced elastomeric encapsulation materials are developed which are intended to be intrinsically free of in-situ ionic impurities, have ultralow water absorption, be weather-stable (UV, oxygen), and have high mechanical flexibility. Efforts to develop a method of assessing the life potential of organic insulation materials in photovoltaic modules are described.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 147-154
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  • 63
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    Hipot and continuity qualification est experience (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: High voltage potential (Hipot) and module frame continuity tests are important parts of determining the suitability of solar modules for deployment into large arrays for electrical power production. Since field arrays operate at hundreds of volts above (or below) ground potential at some point in the field, it is necessary to assure adequate voltage isolation of the solar cell circuits.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 105-121
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  • 64
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    Laboratory experience with voltage breakdown (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Voltage breakdown failures in photovoltaic module electrical insulations lead to loss of entire source circuits and require costly maintenance and replacement. Avoiding such catastrophes requires that modules be designed so that voltage breakdown either never occurs or occurs so rarely that it affects the least life cycle energy costs insignificantly. To achieve this desired balance of cost and reliability, the module design engineer must understand the failure mechanisms and use data on materials and failue rates to suppress or retard them. Recently obtained failure mechanism information, rate data and materials property data and a qualitative model of module failure prediction are presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 123-146
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  • 65
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    Electrical insulation design requirements and reliability goals (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The solar cells in a photovoltaic module which must be electrically isolated from module exterior surfaces to satisfy a variety of safety and operating considerations are discussed. The performance and reliability of the insulation system are examined. Technical requirements involve the capability of withstanding the differential voltage from the solar cells to the module frame. The maximum system voltage includes consideration of maximum open circuit array voltages achieved under low-temperature, high-irradiance conditions, and transient overvoltages due to system feedback of lightning transients. The latter is bounded by the characteristics of incorporated voltage limiting devices such as MOVs.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 95-104
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  • 66
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    Design and selection of bypass diodes (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Topics concerning the design and use of bypass diodes are investigated. Energy output, service life, safety, cell mounting approach, thermal capability, and cost analysis are also considered.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 49-49
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  • 67
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    Source circuit design considerations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The cost of several circuit configurations for large (5MW) array fields were investigated to assess the relative costs of high and low voltage configurations. Three source circuit NOC voltages were evaluated: 400V (ungrounded), 800V (+ or 400V center grounded), and 2000V (+ or - 1000V center grounded). Four source circuit configurations were considered for each of the three NOC voltages. The configurations correspond to source circuit currents of 15, 30, 45, and 60 amperes, respectively. Conceptual layouts for 5MW building blocks for each of the above configurations were developed. The designs were optimized to minimize BOS electrical and structural costs. Only the BOS electrical costs were evaluated. The designs were broken down into the following elements for cost: (1) basic source circuit intermodule wiring, bypass diodes and associated hardware, source circuit to J-Box wiring, etc; (2) J-Box blocking diodes, varistors, heat sinks, and housing; (3) disconnects source circuit disconnects, fuses, and housing; (4) bus cabling J-Box to PCU interface wiring, and trenching; (5) interface bus bar, group disconnects, and fuses; and (6) fault detection shunts, signal wire, electronics, and alarm. It is concluded that high voltage low current circuits are not economical, at higher currents high and low voltage circuit costs approach each other, high voltage circuits are not likely to offer near term advantage, and development work/manufacturer stimulation is needed to develop low cost high voltage hardware.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 81-90
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  • 68
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    A review and summary of cell and module mismatch losses from theoretical and experimental studies (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Studies on power loss due to photovoltaic (PV) cell and module parameter mismatch were reviewed. The losses result from the current voltage (I-V) characteristics of cells which vary over a manufactured lot. The peak power and the peak power I-V point vary from cell to cell. The largest parameter variation occurs in the cell photocurrent generation and the most significant loss occurs in series connections since all cells are essentially limited by the lowest photocurrent. Most theoretical studies address only photocurrent variation effects, which consider shunt and series resistance, ideality factor and saturation current to be comparatively insignificant. One study is identified which specifically configured the study of mismatch loss effects. Experimental results consist of estimates based on limited data not taken from specially configured tests.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 61-79
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  • 69
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    Source-circuit design with multiple photovoltaic manufacturers (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The problems associated with source circuit design for use in photovoltaic (PV) hardware of different manufacturers or processes are discussed. The varying performance of dissimilar materials is examined and the need for standardization of equipment and performance output is investigated.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: JPL Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 15-18
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  • 70
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    Source-circuit design overview (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The source circuit is the fundamental electrical building block of a large central-station array; it consists of a series-parallel network of solar cells that develops full system voltage. The array field is generally made up of a large number of parallel source circuits. Source-circuit electrical configuration is driven by a number of design considerations, which must be considered simultaneously. Array fault tolerance and hot spot heating endurance are examined in detail.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 7-14
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  • 71
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    Hot-spot heating in central-station arrays (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Hot spot tests performed on the Sacramento Municipal Utility District (SMUD) verificaton array show that current imbalance occurs, resulting in significant hot spot heating. One cause of current imbalance is differences in the average shunt resistances of parallel cell strings due to cell shunt resistance variations. In depth hot spot tests are performed on the verification array with bypass diodes. The tests had several objectives: (1) a comparison of hot spot temperatures achieved under field conditions with those obtained with the present laboratory hot spot test using similar modules; (2) an assessment of current imbalance versus cross tie frequency; and (3) an assessment of different shadow patterns and shadow densities. Instrumented modules are used to vary the number of cross ties and to measure the test-cell current and back-bias voltage. The widths, lengths, and densities of the shadows are varied to maximize the back bias voltage at maximum power current. An infrared camera is used to indicate the existence of hot spots and estimate temperature increases in conjunction with thermocouples. The results of these hot spot tests indicate a sensitivity of back bias heating to the shadow size (amount of cell coverage) and density.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Proc. of the Flat-Plate Solar Array Proj. Res. Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Sta.; p 19-36
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  • 72
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    Influence of radiative recombination on the minority-carrier transport in direct band-gap semiconductors (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: When a semiconductor sample is irradiated by means of an external source, emitting photons or electrons, excess carriers are produced which distribute themselves throughout the sample. One of the parameters which determine the distribution of the carriers is the surface recombination velocity. The present investigation is concerned with the recombination lifetime tau. The predominant mechanism for recombination in wide band-gap semiconductors is described by the Shockley-Read-Hall (SRH) theory. The transport equations are derived for free carriers and the radiation field. The considered theory is applied to a semiinfinite, one-dimensional semiconductor slab irradiated by light of a given frequency. Some numerical considerations based on n-type GaAs are presented. Attention is given to a determination of the radiation transmitted through the surface of the sample.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 54; March 19
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  • 73
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    GaAs microwave devices and circuits with submicron electron-beam defined features (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper describes the fabrication and application of GaAs FET's, both as discrete microwave devices and as the key active components in monolithic microwave integrated circuits. The performance of these devices and circuits is discussed for frequencies ranging from 3 to 25 GHz. The crucial fabrication step is the formation of the submicron gate by electron-beam lithography.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE, Proceedings (ISSN 0018-9218); 71; May 1983
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  • 74
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    Sensitive method for characterizing liquid helium cooled preamplifier feedback resistors (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is pointed out that the simple and traditional method of measuring resistance using an electrometer is ineffective since it is limited to a narrow and nonrepresentative range of terminal voltages. The present investigation is concerned with a resistor measurement technique which was developed to select and calibrate the Transimpedance Mode Amplifier (TIA) load resistors on the Infrared Astronomical Satellite (IRAS) for the wide variety of time and voltage varying signals which will be processed during the flight. The developed method has great versatility and power, and makes it possible to measure the varied and complex responses of nonideal feedback resistors to IR photo-detector currents. When employed with a stable input coupling capacitor, and a narrow band RMS voltmeter, the five input waveforms thouroughly test and calibrate all the features of interest in a load resistor and its associated TIA circuitry.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 75
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    A new inverter topology using GTO commutation (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A new N-phase, forced commutated bridge inverter topology has been developed wherein a single Gate Turn Off Thyristor (GTO) is used to commutate each of 2N main Thyristors (SCRs). Since, for most applications, the primary loss mechanism is the SCR forward drop, very high efficiencies are possible. Compared with conventional pure SCR and pure GTO inverters, cost per kW is lower - in the former case due to the large cost differential between GTOs and SCRs. Other advantages of the new inverter include high power density, low switching losses and stresses, modulation flexibility and amenability to high voltage and high frequency operation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 76
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    Brief characterization of germanium junction field effect transistors (FETs) at 77, 4, and 1.8 K (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In the case of modern infrared focal planes, one of the major problems is related to the noise contribution of the cooled, impedance-matching device used as the preamplifier stage in the detector electronics system. An ideal preamp device should have the low-noise advantages of a buried-channel device and operate isothermally with the low-temperature detector array. The Ge JFET might provide this ideal device. A testing program with Ge JFETs is discussed. It is concluded that germanium JFETs offer an attractive alternative for cryogenic preamplifier designs. They operate well with high transconductance and low noise at LHe temperatures. It is believed that these devices point the way for the development of large, integrated-array, long wavelength, infrared focal planes which incorporate germanium detectors, germanium load resistors, and germanium preamplifiers within the same monolithic structure.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 77
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    Coherent integration (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Coherent integration which is a digital filtering process and was applied to MST radar observations is discussed. It is simple to implement with either hardware or software and is appropriate for the very narrow band signals usually received by MST radars. By filtering the signal before performing spectral processing, the computations required for FFT or similar analysis are greatly reduced. Coherent integration does not increase the signal-to-noise ratio per unit bandwidth in the signal band. It filters out much of the wideband noise, which could also be done by full FFT processing of the raw signal.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: International Council of Scientific Unions Middle Atmosphere Program, Vol. 9; p 507-508
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  • 78
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    A polytetrafluorethylene insulated cable for high temperature oxygen aerospace applications (1983)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: For electrical cables to function and survive in the severe high temperature oxygen environment that will be experienced in the external tanks of the space shuttle, extreme cleanliness and material purity is required. A flexible light weight cable has been developed for use in pure oxygen at worst case temperatures of -190 to +260 degrees Centigrade and pressures as high as 44 pounds per square inch absolute. A comprehensive series of tests were performed on cables manufactured to the best commercial practices in order to establish the basic guidelines for control of build configuration as well as each material used in construction of the cable.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Army Commun.-Electron. Command Proc. of the 32nd Intern. Wire and Cable Symp.; p 183-192
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  • 79
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    Optimization of a magnet circuit design for a cylindrical mass spectrometer (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The results of an optimization effort to achieve a minimum weight configuration for a magnetic section circuit (MSC) used in the magnetic portion of a double-focusing mass spectrometer is presented.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-176400 , NAS 1.26:176400 , PT-6440
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  • 80
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    Polynomial driven time base and PN generator (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: In support of the planetary radar upgrade new hardware was designed to increase resolution and take advantage of new technology. Included is a description of the Polynomial Driven Time Base and PN Generator which is used for range gate coding in the planetary radar system.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommun. and Data Acquisition Rept.; p 84-90
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  • 81
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    An EPROM-based function generator (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A circuit is described to produce arbitrary time-dependent voltage functions derived from digital information stored in EPROMs. While this circuit is designed to be used as a modulator of the microwave pump source or a solid state low noise maser, it can be readily adapted for other applications.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: The Telecommun. and Data Acquisition Rept.; p 79-83
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  • 82
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    Cycloconverter on the all-electric airplane (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper discusses the application of a cycloconverter to a permanent magnet generator. Recent developments, advanced concepts, and advanced technology systems will be covered. Recent developments include permanent magnets, permanent magnet motors and generators, and power semiconductors.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 173-188
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  • 83
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    DC-link approach to constant-frequency aircraft power (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper discusses a hybrid high-power aircraft electrical system that has very difficult and complex operating requirements. Many issues raised in selecting an approach for this application are similar to those that must eventually be addressed for a large all-electric aircraft. The requirements for this specific system are reviewed, a solution for those requirements is proposed, and some explanation is provided for the choice. Because the system requires a substantial amount of 400-Hz power, a dc-link system was selected to provide that power.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 159-172
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  • 84
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    High-current, high-frequency capacitors (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The NASA Lewis high-current, high-frequency capacitor development program was conducted under a contract with Maxwell Laboratories, Inc., San Diego, California. The program was started to develop power components for space power systems. One of the components lacking was a high-power, high-frequency capacitor. Some of the technology developed in this program may be directly usable in an all-electric airplane. The materials used in the capacitor included the following: the film is polypropylene, the impregnant is monoisopropyl biphenyl, the conductive epoxy is Emerson and Cuming Stycast 2850 KT, the foil is aluminum, the case is stainless steel (304), and the electrode is a modified copper-ceramic.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Aircraft Elect. Secondary Power; p 149-158
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  • 85
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    Lightweight, high-frequency transformers (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The 25-kVA space transformer was developed under contract by Thermal Technology Laboratory, Buffalo, N. Y. The NASA Lewis transformer technology program attempted to develop the baseline technology. For the 25-kVA transformer the input voltage was chosen as 200 V, the output voltage as 1500 V, the input voltage waveform as square wave, the duty cycle as continuous, the frequency range (within certain constraints) as 10 to 40 kHz, the operating temperatures as 85 deg. and 130 C, the baseplate temperature as 50 C, the equivalent leakage inductance as less than 10 micro-h, the operating environment as space, and the life expectancy as 10 years. Such a transformer can also be used for aircraft, ship and terrestrial applications.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Aircraft Elect. Secondary Power; p 143-147
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  • 86
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    New developments in power semiconductors (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper represents an overview of some recent power semiconductor developments and spotlights new technologies that may have significant impact for aircraft electric secondary power. Primary emphasis will be on NASA-Lewis-supported developments in transistors, diodes, a new family of semiconductors, and solid-state remote power controllers. Several semiconductor companies that are moving into the power arena with devices rated at 400 V and 50 A and above are listed, with a brief look at a few devices.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Aircraft Elect. Secondary Power; p 123-141
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  • 87
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    Intercalated graphite electrical conductors (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: For years NASA has wanted to reduce the weight of spacecraft and aircraft. Experiments are conducted to find a lightweight synthetic metal to replace copper. The subject of this paper, intercalated graphite, is such a material. Intercalated graphite is made by heating petroleum or coal to remove the hydrogen and to form more covalent bonds, thus increasing the molecular weight. The coal or petroleum eventually turns to pitch, which can then be drawn into a fiber. With continued heating the pitch-based fiber releases hydrogen and forms a carbon fiber. The carbon fiber, if heated sufficiently, becomes more organized in parallel layers of hexagonally arranged carbon atoms in the form of graphite. A conductor of intercalated graphite is potentially useful for spacecraft or aircraft applications because of its low weight.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Aircraft Elect. Secondary Power; p 103-122
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  • 88
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    Three-phase, high-voltage, high-frequency distributed bus system for advanced aircraft (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A three phase, high voltage, high frequency distributed bus system for advanced aircraft is discussed. A system model is given. Available components are described. Recommendations are given.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Aircraft Elect. Secondary Power; p 27-35
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  • 89
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    High-voltage (270 V) dc power-generating system for fighter aircraft (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The advantages of using high voltage, direct current advanced power generating systems in fighter aircraft are discussed. Weight reduction is achieved. Efficiency is increased 85 to 90 percent by eliminating the constant speed drive. Power interruptions are eliminated. There are no speed restrictions and no powerline constraints. Personal safety is increased by eliminating the hold on frequency, present in ac systems, which causes muscle contractions.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 13-25
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    The 400-Hz aircraft power-generation systems: Advancing the baseline (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Today's benchmark system for the Boeing 757/767/A310 airplanes and future trends in hydromechanical aircraft power generating systems are discussed. The 757/767/A310 system represents the commercial state of the art and the direction in which Sundstrand Corp. is headed, particularly in regard to weight reduction. Sundstrand introduced microprocessor control in an in service system in the Boeing 767 and was the first to use databus communications between the controls. Plans to develop this technology are briefly discussed. Alternative ways to produce and use power in aircraft are discussed. The integrated starter drive is discussed.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Lewis Research Center Aircraft Elect. Secondary Power; p 1-12
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    Architecture and performance of a new GPS time transfer and positioning receiver (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This paper describes the Interstate Electronics 4200 GPS Receiver System that has been developed for time transfer and low dynamic positioning applications. The receiver employs the NAVSTAR Global Positioning System (GPS) l sub 1 C/A code and has three optional solution modes fo the clock/navigation state estimation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center Proc. of the 14th Ann. Precise Time and Time Interval (PTTI) Appl. Planning Meeting; p 495-516
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  • 92
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    The fundamental structure function of oscillator noise models (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Continuous-time models of oscillator phase noise x(t) usually have stationary nth differences, for some n. The covariance structure of such a model can be characterized in the time domain by the structure function: D sub n (t;gamma sub 1, gamma sub 2) = E delta (n) sub gamma sub 1 x(s+t) delta(n) sub gamma sub 2 x (s). Although formulas for the special case D sub 2 (0;gamma,gamma) (the Allan variance times 2 gamma(2)) exist for power-law spectral models, certain estimation problems require a more complete knowledge of (0). Exhibited is a much simpler function of one time variable, D(t), from which (0) can easily be obtained from the spectral density by uncomplicated integrations. Believing that D(t) is the simplest function of time that holds the same information as (0), D(t) is called the fundamental structure function. D(t) is computed for several power-law spectral models. Two examples are D(t) = K/t/(3) for random walk FM, D(t) = Kt(2) 1n/t/ for flicker FM. Then, to demonstrate its use, a BASIC program is given that computes means and variances of two Allan variance estimators, one of which incorporates a method of frequency drift estimation and removal.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center Proc. of the 14th Ann. Precise Time and Time Interval (PTTI) Appl. Planning Meeting; p 281-294
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  • 93
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    Influence of modulation frequency in rubidium cell frequency standards (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The error signal which is used to control the frequency of the quartz crystal oscillator of a passive rubidium cell frequency standard is considered. The value of the slope of this signal, for an interrogation frequency close to the atomic transition frequency is calculated and measured for various phase (or frequency) modulation waveforms, and for several values of the modulation frequency. A theoretical analysis is made using a model which applies to a system in which the optical pumping rate, the relaxation rates and the RF field are homogeneous. Results are given for sine-wave phase modulation, square-wave frequency modulation and square-wave phase modulation. The influence of the modulation frequency on the slope of the error signal is specified. It is shown that the modulation frequency can be chosen as large as twice the non-saturated full-width at half-maximum without a drastic loss of the sensitivity to an offset of the interrogation frequency from center line, provided that the power saturation factor and the amplitude of modulation are properly adjusted.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA. Goddard Space Flight Center Proc. of the 14th Ann. Precise Time and Time Interval (PTTI) Appl. Planning Meeting; p 87-112
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  • 94
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    Acoustooptic pulse-echo transducer system (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A pulse-echo transducer system which uses an ultrasonic generating element and an optical detection technique is described. The transmitting transducer consists of a concentric ring electrode pattern deposited on a circular, X-cut quartz substrate with a circular hole in the center. The rings are independently pulsed with a sequence high voltage signals phased in such a way that the ultrasonic waves generated by the separate rings superimpose to produce a composite field which is focused at a controllable distance below the surface of the specimen. The amplitude of the field reflected from this focus position is determined by the local reflection coefficient of the medium at the effective focal point. By processing the signals received for a range of ultrasonic transducer array focal lengths, the system can be used to locate and size anomalies within solids and liquids. Applications in both nondestructive evaluation and biomedical scanning are suggested.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-175919 , NAS 1.26:175919
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  • 95
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    Radiation immune RAM semiconductor technology for the 80's (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: This paper presents current and short term future characteristics of RAM semiconductor technologies which were obtained by literature survey and discussions with cognizant Government and industry personnel. In particular, total ionizing dose tolerance and high energy particle susceptibility of the technologies are addressed. Technologies judged compatible with spacecraft applications are ranked to determine the best current and future technology for fast access (less than 60 ns), radiation tolerant RAM.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Format: text
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  • 96
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    AC propulsion system for an electric vehicle, phase 2 (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: NASA-CR-168244 , DOE/NASA/0211-1 , NAS 1.26:168244 , ERC-TR-83024
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  • 97
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    Motor power control circuit for ac induction motors (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A motor power control of the type which functions by controlling the power factor wherein one of the parameters of power factor current on time is determined by the on time of a triac through which current is supplied to the motor. By means of a positive feedback circuit, a wider range of control is effected.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
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  • 98
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    Transformer induced instability of the series resonant converter (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: It is shown that the common series resonant power converter is subject to a low frequency oscillation that can lead to the loss of cyclic stability. This oscillation is caused by a low frequency resonant circuit formed by the normal L and C components in series with the magnetizing inductance of the output transformer. Three methods for eliminating this oscillation are presented and analyzed. One of these methods requires a change in the circuit topology during the resonance cycle. This requires a new set of steady state equations which are derived and presented in a normalized form. Experimental results are included which demonstrate the nature of the low frequency oscillation before cyclic stability is lost.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: IEEE Transactions on Aerospace and Electronic Systems (ISSN 0018-9251); 19; May 1983
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  • 99
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    GaAs integrated digital-to-analogue convertor for control of power dual-gate FETs (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The design, fabrication and performance of a TTL compatible 4-bit GaAs integrated digital-to-analog convertor with an output voltage between -2.8 V and +2.8 V are reported. This circuit has been especially designed to control the gain of power dual-gate FETs by applying a voltage on the capacitively terminated second gate.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Electronics Letters (ISSN 0013-5194); 19; March 3
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  • 100
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    Ohmic contacts for laser diodes (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Requirements for ohmic contacts to laser diodes are discussed, and properties of Schottky barrier tunneling contacts are reviewed. A procedure is described for measuring contact resistance on fabricated laser material without the need for specially constructed samples and contact configurations. Measurements of contact resistance and estimates of specific contact resistance are given for Ti/Pt/Au contacts to surfaces with three different doping levels. It was found that below a p-type carrier concentration of 1 x 10 to the 19th per cu cm the contact resistance is likely to be too high for good device performance. At higher doping levels, a specific contact resistance as low as 2 x 10 to the -6th ohm sq cm was obtained. Oxide stripe lasers provided with the type of contact discussed in this paper have been operated without failures for periods up to 7 years at a current density at the contact of 6-8 kA/sq cm. It appears therefore that these contacts satisfy the need for low resistance and durability and that, at the same time, they do not cause any obvious material degradation.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: RCA Review (ISSN 0033-6831); 44; March 19
    Format: text
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