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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Hardware additions to microprocessor architecture aid software development

An address trap (breakpoint) mechanism and last-in-first-out (LIFO) address stack are suggested as two additions to the basic microprocessor architecture whose functions are solely to aid the programmer. These devices provide the programmer with the ability to specify address breakpoints and to trace program execution back through N instructions, where N is the depth of the stack. Both devices, plus interface logic and buffering, have been designed for an INTEL 8080-based system using approximately 25 integrated-circuit packages.

Sievers, M. W.↗
NASA NTRS1977

Ergometer

The bicycle ergometer was designed for use in experiments M171 and M093 and for use in optional exercise by the crewmen. The ergometer allows a crewman to exercise in zero-gravity using either his hands or his feet. It provides a precisely calibrated and, if needed, a programmable standard of work rate for the crewman. The ergometer operates in any of three selectable modes. The set heart rate mode varies the ergometer work rate, as necessary, to achieve and maintain a preselected heart rate. The sequenced heart rate mode is similar to the set heart rate mode except that the heart rate is programmable through five preset levels with a period of time for each level. The set work rate mode delivers a preset work load to the subject.

Lem, J. D.↗
NASA NTRS1978

A cycle timer for testing electric vehicles

A cycle timer was developed to assist the driver of an electric vehicle in more accurately following and repeating SAE driving schedules. These schedules require operating an electric vehicle in a selected stop-and-go driving cycle and repeating this cycle pattern until the vehicle ceases to meet the requirements of the cycle. The heart of the system is a programmable read-only memory (PROM) that has the required test profiles permanently recorded on plug-in cards, one card for each different driving schedule. The PROM generates a direct current analog signal that drives a speedometer displayed on one scale of a dual movement meter. The second scale of the dual movement meter displays the actual speed of the vehicle as recorded by the fifth wheel. The vehicle operator controls vehicle speed to match the desired profile speed. The PROM controls the recycle start time as well as the buzzer activation. The cycle programmer is powered by the test vehicle's 12-volt accessory battery, through a 5-volt regulator and a 12-volt dc-to-dc converter.

Soltis, R. F.↗
NASA NTRS1978

Operational manual for two-dimensional transonic code TSFOIL

This code solves the two-dimensional, transonic, small-disturbance equations for flow past lifting airfoils in both free air and various wind-tunnel environments by using a variant of the finite-difference method. A description of the theoretical and numerical basis of the code is provided, together with complete operating instructions and sample cases for the general user. In addition, a programmer's manual is also presented to assist the user interested in modifying the code. Included in the programmer's manual are a dictionary of subroutine variables in common and a detailed description of each subroutine.

Stahara, S. S.↗
NASA NTRS1978

Improvements of the gravity field from satellite techniques as proposed to the European Space Agency

A summary of the European Earth Sciences Space Programme and the requirements for each gravity field mapping resulting from this programme are given. Three satellite experiments for gravity field improvement proposed to the European Space Agency in the last years are shortly characterized. One of these experiments, the low-low-SST-SLALOM experiment, based on laser interferometry for a "two target-one Spacelab telescope" configuration, is discussed in more detail. Reasons for the low-low concept selection are given and some mission aspects and a possible system concept for a compact ranging, acquisition and tracking system are presented.

Reigber, C.↗
NASA NTRS1978

Advanced systems requirements for ocean observations via microwave radiometers

A future microwave spectroradiometer operating in several frequency bands will have the capability to step or sweep frequencies on an adaptable or programmable basis. The on-board adaptable frequency shifting can make the systems immune from radio interference. Programmable frequency sweeping with on-board data inversion by high speed computers would provide for instantaneous synoptic measurements or sea surface temperature and salinity, water surface and volume pollution, ice thickness, ocean surface winds, snow depth, and soil moisture. Large structure satellites will allow an order of magnitude improvement in the present radiometric measurement spacial resolution.

Blume, H.-J. C.↗
NASA NTRS1979

Microcomputer programming skills

Some differences in skill and techniques required for conversion from programmer to microprogrammer are discussed. The primary things with which the programmer should work are hardware architecture, hardware/software trade off, and interfacing. The biggest differences, however, will stem from the differences in applications than from differences in machine size. The change to real-time programming is the most important of these differences, particularly on dedicated microprocessors. Another primary change is programming with a more computer-naive user in mind, and dealing with his limitations and expectations.

Barth, C. W.↗
NASA NTRS1980

Process development for automated solar cell and module production. Task 4: Automated array assembly

A process sequence which can be used in conjunction with automated equipment for the mass production of solar cell modules for terrestrial use was developed. The process sequence was then critically analyzed from a technical and economic standpoint to determine the technological readiness of certain process steps for implementation. The steps receiving analysis were: back contact metallization, automated cell array layup/interconnect, and module edge sealing. For automated layup/interconnect, both hard automation and programmable automation (using an industrial robot) were studied. The programmable automation system was then selected for actual hardware development.

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NASA NTRS1981

Controller for computer control of brushless dc motors

A motor speed and torque controller for brushless d.c. motors provides an unusually smooth torque control arrangement. The controller provides a means for controlling a current waveform in each winding of a brushless dc motor by synchronization of an excitation pulse train from a programmable oscillator. Sensing of torque for synchronization is provided by a light beam chopper mounted on the motor rotor shaft. Speed and duty cycle are independently controlled by controlling the frequency and pulse width output of the programmable oscillator. A means is also provided so that current transitions from one motor winding to another is effected without abrupt changes in output torque.

Hieda, L. S.↗
NASA NTRS1980

Universal delta modulation receivers using the bit slice approach

The architecture of programmable processors is described, with particular reference to the design of a programmable delta-modulation decoder capable of receiving DM encoders employing different schemes. A switching receiver implementation, allowing communication between different DM algorithms, is designed and shown.

Apelewicz, T.↗
NASA NTRS1981

Memory-based frame synchronizer

A frame synchronizer for use in digital communications systems wherein data formats can be easily and dynamically changed is described. The use of memory array elements provide increased flexibility in format selection and sync word selection in addition to real time reconfiguration ability. The frame synchronizer comprises a serial-to-parallel converter which converts a serial input data stream to a constantly changing parallel data output. This parallel data output is supplied to programmable sync word recognizers each consisting of a multiplexer and a random access memory (RAM). The multiplexer is connected to both the parallel data output and an address bus which may be connected to a microprocessor or computer for purposes of programming the sync word recognizer. The RAM is used as an associative memory or decorder and is programmed to identify a specific sync word. Additional programmable RAMs are used as counter decoders to define word bit length, frame word length, and paragraph frame length.

Stattel, R. J.↗
NASA NTRS1982

Thermal monitoring, measurement, and control system for a Volatile Condensable Materials (VCM) test apparatus

A thermal monitoring and control concept is described for a volatile condensable materials (VCM) test apparatus where electric resistance heaters are employed. The technique is computer based, but requires only proportioning ON/OFF relay control signals supplied through a programmable scanner and simple quadrac power controllers. System uniqueness is derived from automatic temperature measurements and the averaging of these measurements in discrete overlapping temperature zones. Overall control tolerance proves to be better than + or - 0.5 C from room ambient temperature to 150 C. Using precisely calibrated thermocouples, the method provides excellent temperature control of a small copper VCM heating plate at 125 + or - 0.2 C over a 24 hr test period. For purposes of unattended operation, the programmable computer/controller provides a continual data printout of system operation. Real time operator command is also provided for, as is automatic shutdown of the system and operator alarm in the event of malfunction.

Ives, R. E.↗
NASA NTRS1982

An Automated FORTRAN documenter

A set of programs designed to help R&D programmers document their FORTRAN programs more effectively were written. The central program reads FORTRAN source code and asks the programmer questions about things it has not heard of before. It inserts the answers to these questions as comments into the FORTRAN code. The comments, as well as extensive cross-reference information, are also written to an unformatted file. Other programs read this file to produce printed information or to act as an interactive document.

Erickson, T.↗
NASA NTRS1981

The Lick Observatory charge-coupled device /CCD/ and controller

A description is given of a flexible microprocessor-based controller for charge-coupled device two-dimensional detectors. It is noted that the controller can operate under manual control or as a slave to a remote computer linked by coaxial cable. The system is discussed, together with data taken at the telescope and in the laboratory. The flexibility of the controller derives from its modular form and from the use of a programmable 8-bit microprocessor to control and sequence the electronic logic. The electronic circuits for such functions as signal processing, clock sequencing, voltage level adjustment, and temperature control are on small individual plug-in cards, making future improvements and changes simple. The software of the microprocessor is stored in erasable, programmable, read-only memory. Among the limitations of the controller is a scan speed of roughly 35 microsec per pixel.

Robinson, L. B.↗
NASA NTRS1983

User's manual for three-dimensional analysis of propeller flow fields

A detailed operating manual is presented for the prop-fan computer code (in addition to supporting programs) recently developed by Kutler, Chaussee, Sorenson, and Pulliam while at the NASA'S Ames Research Center. This code solves the inviscid Euler equations using an implicit numerical procedure developed by Beam and Warming of Ames. A description of the underlying theory, numerical techniques, and boundary conditions with equations, formulas, and methods for the mesh generation program (MGP), three dimensional prop-fan flow field program (3DPFP), and data reduction program (DRP) is provided, together with complete operating instructions. In addition, a programmer's manual is also provided to assist the user interested in modifying the codes. Included in the programmer's manual for each program is a description of the input and output variables, flow charts, program listings, sample input and output data, and operating hints.

Chaussee, D. S.↗
NASA NTRS1982

Evaluating software development by analysis of changes: The data from the software engineering laboratory

An effective data collection methodology for evaluating software development methodologies was applied to four different software development projects. Goals of the data collection included characterizing changes and errors, characterizing projects and programmers, identifying effective error detection and correction techniques, and investigating ripple effects. The data collected consisted of changes (including error corrections) made to the software after code was written and baselined, but before testing began. Data collection and validation were concurrent with software development. Changes reported were verified by interviews with programmers.

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NASA NTRS1984

Modular approach for satellite communication ground terminals

The trend in satellite communications is toward completely digital, time division multiple access (TDMA) systems with uplink and downlink data rates dictated by the type of service offered. Trunking terminals will operate in the 550 MBPS (megabit per second) region uplink and downlink, whereas customer premise service (CPS) terminals will operate in the 25 to 10 MBPS region uplink and in the 200 MBPS region downlink. Additional criteria for the ground terminals will be to maintain clock sychronization with the system and burst time integrity to within a matter of nanoseconds, to process required order-fire information, to provide adaptive data scrambing, and to compensate for variations in the user input output data rates, and for changes in range in the satellite communications links resulting from satellite perturbations in orbit. To achieve the required adaptability of a ground terminal to the above mentioned variables, programmable building blocks can be developed that will meet all of these requirements. To maintain system synchronization, i.e., all bursted data arriving at the satellite within assigned TDMA windows, ground terminal transmit data rates and burst timing must be maintained within tight tolerances. With a programmable synchronizer as the heart of the terminal timing generation, variable data rates and burst timing tolerances are achievable. In essence, the unit inputs microprocessor generated timing words and outputs discrete timing pulses.

Gould, G. R.↗
NASA NTRS1983

Evaluating multiple coordinated windows for programming workstations

Programmers might benefit from larger screens with multiple windows or multiple screens, especially if convenient coordination among screens are arranged. Uses for multiple coordinated displays in a programmers workstation are explored. Initial efforts focus on the potential applications, a command language for coordinating the displays, and the psychological basis for effective utilization so as to avoid information overload. Subsequent efforts will be devoted to implementing the concepts and performing controlled psychologically oriented experiments to validate the hypotheses.

Shneiderman, B.↗