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At least 19 records

Timeline Resource Analysis Program (TRAP): User's manual and program document

The Timeline Resource Analysis Program (TRAP), developed for scheduling and timelining problems, is described. Given an activity network, TRAP generates timeline plots, resource histograms, and tabular summaries of the network, schedules, and resource levels. It is written in ANSI FORTRAN for the Honeywell SIGMA 5 computer and operates in the interactive mode using the TEKTRONIX 4014-1 graphics terminal. The input network file may be a standard SIGMA 5 file or one generated using the Interactive Graphics Design System. The timeline plots can be displayed in two orderings: according to the sequence in which the tasks were read on input, and a waterfall sequence in which the tasks are ordered by start time. The input order is especially meaningful when the network consists of several interacting subnetworks. The waterfall sequence is helpful in assessing the project status at any point in time.

Sessler, J. G.↗

IGDS/TRAP Interface Program (ITIP). Software User Manual (SUM)

This specification establishes the requirements, concepts, and preliminary design for a set of software known as the IGDS/TRAP Interface Program (ITIP). This software provides the capability to develop at an Interactive Graphics Design System (IGDS) design station process flow diagrams for use by the NASA Coal Gasification Task Team. In addition, ITIP will use the Data Management and Retrieval System (DMRS) to maintain a data base from which a properly formatted input file to the Time-Line and Resources Analysis Program (TRAP) can be extracted. This set of software will reside on the PDP-11/70 and will become the primary interface between the Coal Gasification Task Team and IGDS, DMRS, and TRAP. The user manual for the computer program is presented.

Jefferys, S.↗

Transient Response Analysis

Transient Response Analysis Program, TRAP aids in analysis of frequency response of force-transmission and shock-damping devices. Devices analyzed with TRAP include hydraulic actuators, automotive shock absorbers and electromechanical actuators.

Blackman, L. D.↗

The NASA/National Space Science Data Center trapped radiation environment model program, 1964 - 1991

The major effort that NASA, initially with the help of the United States Air Force (USAF), carried out for 27 years to synthesize the experimental and theoretical results of space research related to energetic charged particles into a quantitative description of the terrestrial trapped radiation environment in the form of model environments is detailed. The effort is called the Trapped Radiation Environment Modeling Program (TREMP). In chapter 2 the historical background leading to the establishment of this program is given. Also, the purpose of this modeling program as established by the founders of the program is discussed. This is followed in chapter 3 by the philosophy and approach that was applied in this program throughout its lifetime. As will be seen, this philosophy led to the continuation of the program long after it would have expired. The highlights of the accomplishments are presented in chapter 4. A view to future possible efforts in this arena is given in chapter 5, mainly to pass on to future workers the differences that are perceived from these many years of experience. Chapter 6 is an appendix that details the chronology of the development of TREMP. Finally, the references, which document the work accomplished over these years, are presented in chapter 7.

Vette, James I.↗

Cold trap fractionation as an organic analysis technique.

A highly simplified, alternate approach to the gas chromatograph-mass spectrometer has been developed. In this approach, a low temperature trap replaces the entire GC portion of the combined GC-MS instrument and no carrier gas is necessary. Using the cold trap technique, the sample is first passed into a chilled trap. Depending on the trap temperature, many compounds are condensed or trapped out (most at -196 C). Those which are not, such as helium, neon, and nitrogen, pass through the trap directly into the spectrometer for analysis. Then the trap is programmed to increase in temperature at an appropriate rate. This allows evaporation (or sublimation) of the trapped materials according to the specific vapor pressure characteristics of the compound, providing some temporal separation between constituents. These partially resolved components are directed to the MS as they evolve from the trap.

Crosmer, W. E.↗

An efficient microcomputer system for the analysis of particle image velocimetry specklegrams

An efficient image processing system is described for the automatic analysis of particle image velocimetry (PIV) fringe patterns. Each interrogation point takes 1 second to analyze; a complete specklegram can be interrogated at 1000 points in approximately 15 minutes. Incorporated in the analysis is a means for automatic replacement of spurious velocity vectors without either re-interrogation of the specklegram or interpolation between neighboring data points. The sucess of the above system is demonstrated by application of the PIV technique to the study of the sink-driven cavity flow. This flow is studied as part of a larger program to investigate trapped vortex flows as a means of lift enhancement on swept wings.

Wadcock, Alan J.↗

Laboratory investigations of volatile trapping in comets

This research program consists of laboratory studies of the formation of ice at low temperatures to simulate the formation of comets in the outer solar nebula. The ice is condensed in the presence of various mixtures of gases at a given temperature, and then warmed to see at what temperatures the gases are released and how much gas was actually trapped. Our results to date indicate that the trapping of argon, krypton, and xenon in ice formed at approximately 50 K fractionates these gase in a way that fits the relative abundances found in the atmospheres of Mars and Earth. This is markedly different from the situation in chondritic meteorites, where the abundance of xenon is about equal to that of krypton. It appears that comets represent a better source for planetary volatiles than do the meteorites.

Owen, Tobias↗

Grid2: A Program for Rapid Estimation of the Jovian Radiation Environment: A Numeric Implementation of the GIRE2 Jovian Radiation Model for Estimating Trapped Radiation for Mission Concept Studies

Grid2 is a program that utilizes the Galileo Interim Radiation Electron model 2 (GIRE2) Jovian radiation model to compute fluences and doses for Jupiter missions. (Note: The iterations of these two softwares have been GIRE and GIRE2; likewise Grid and Grid2.) While GIRE2 is an important improvement over the original GIRE radiation model, the GIRE2 model can take as long as a day or more to compute these quantities for a complete mission. Grid2 fits the results of the detailed GIRE2 code with a set of grids in local time and position thereby greatly speeding up the execution of the model--minutes as opposed to days. The Grid2 model covers the time period from 1971 to 2050and distances of 1.03 to 30 Jovian diameters (Rj). It is available as a direct-access database through a FORTRAN interface program. The new database is only slightly larger than the original grid version: 1.5 gigabytes (GB) versus 1.2 GB.

Europa↗

An OPS5 expert system converted to FORPS

FORPS, a simple Forth-based production system, has been used to reimplement TRAPS, an expert system originally programmed in OPS5 to perform input data checking in Goddard's Communications Link Analysis and Simulation System (CLASS). The FORPS version of TRAPS is implemented both on the CLASS computer and on an IBM PC/AT compatible machine (Hewlett-Packard Vectra). This paper presents results of the TRAPS reimplementation; compares FORPS with OPS5, including efficiency on the HP Vectra; and offers suggestions for enhancements to FORPS.

Rash, James L.↗

Avalanche-diode oscillator circuit with tuning at multiple frequencies

Detailed theoretical analysis of three different modes or types of high efficiency oscillation in a PIN diode are presented. For the TRAPATT mode in a PIN diode, it is shown that a traveling avalanche zone is not necessary to generate a dense trapped plasma. An economical computer program for TRAPATT oscillations in a PIN diode is described. Typical results of diode power, dc-to-RF conversion efficiency, and required circuit impedances are presented for several different current waveforms. A semianalytical solution for a second type of high efficiency mode in a PIN diode is derived assuming a rectangular current waveform. A quasi-static approximation is employed to derive a semianalytical solution for the voltage across a PIN diode in a third mode, where avalanching occurs during a major portion of a half cycle. Calculations for this mode indicate that the power increases proportionally to the magnitude of the drive current with a small decrease in efficiency relative to the ordinary TRAPATT mode. An analytical solution is also given for a PIN diode, where it is assumed that the ionization coefficient is a step function. It is shown that the step-ionization approximation permits one to draw possible patterns of avalanche region in the depletion layer as a function of time. A rule governing admissible patterns is derived and an example solution given for one admissible pattern. Preliminary experimental results on the high-efficiency oscillations are presented and discussed. Two different experimental circuits, which used channel-dropping filters to provide independent harmonic tuning, are described. Simpler circuits used to produce high-efficiency oscillations are discussed. Results of experiments using inexpensive Fairchild FD300 diodes are given.

Parker, D.↗

Using Space Weather Variability in Evaluating the Environment Design Specifications for NASA'S Constellation Program

Spectral models of solar particle events and trapped radiation belts are necessary for the design requirements of total ionizing radiation dose, single event effects, and spacecraft charging. Space radiation and plasma environment specifications for hardware design are necessarily conservative to assure system robustness for a wide range of space environments.

Coffey, Victoria N.↗