Search NASA⌕ Search

SEARCH · Search NASA

Results for “state charts”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

The 25-MB sounding data and synoptic charts for NASA's AVE 2 pilot experiment

Rawinsonde data were tabulated at 25-mb intervals from the surface to 25 mb for the 54 stations participating in the atmospheric variability experiment 2 Pilot Experiment which began at 12 Greenwich mean time on May 11 and ended at 12 Greenwich mean time on May 12, 1974. Soundings were made at 3 hour intervals. Methods of processing and data accuracy are discussed, and synoptic charts prepared from the data are presented. The area covered by the sounding stations is the eastern United States east of approximately 105 deg west longitude.

Scoggins, J. R.↗
NASA NTRS1973

Computer program for determining rotational line intensity factors for diatomic molecules

A FORTRAN IV computer program, that provides a new research tool for determining reliable rotational line intensity factors (also known as Honl-London factors), for most electric and magnetic dipole allowed diatomic transitions, is described in detail. This users manual includes instructions for preparing the input data, a program listing, detailed flow charts, and three sample cases. The program is applicable to spin-allowed dipole transitions with either or both states intermediate between Hund's case (a) and Hund's case (b) coupling and to spin-forbidden dipole transitions with either or both states intermediate between Hund's case (c) and Hund's case (b) coupling.

Whiting, E. E.↗
NASA NTRS1974

Data for NASA's AVE 2 pilot experiment. Part 1: 25-mb sounding data and synoptic charts

Tabulated rawinsonde data at 25-mb intervals from surface to 25 mb is presented for the 54 stations participating in the Atmospheric Variability Experiment 11 pilot experiment which began at 12 GMT on May 11, 1974, and ended at 12 GMT on May 12, 1974. Soundings were made at 3 hour intervals. A brief discussion is included on methods of processing and data accuracy, and synoptic charts prepared from the the data are presented. The area covered by the sounding stations is the eastern United States, east of approximately 105 deg west longitude.

Scoggins, J. R.↗
NASA NTRS1984

Real-time hybrid computer simulation of a small turboshaft engine and control system

The development of an analytical model of a small turboshaft engine designed for helicopter propulsion systems is described. The model equations were implemented on a hybrid computer system to provide a real time nonlinear simulation of the engine performance over a wide operating range. The real time hybrid simulation of the engine was used to evaluate a microprocessor based digital control module. This digital control module was developed as part of an advanced rotorcraft control program. After tests with the hybrid engine simulation the digital control module was used to control a real engine in an experimental program. A hybrid simulation of the engine's electrical hydromechanical control system was developed. This allowed to vary the fuel flow and torque load inputs to the hybrid engine simulation for simulating transient operation. A steady-state data and the experimental tests are compared. Analytical model equations, analog computer diagrams, and a digital computer flow chart are included.

Hart, C. E.↗
NASA NTRS1991

User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 2: Appendixes A-K

The appendices A-K to the user's manual for the rocket combustor interactive design (ROCCID) computer program are presented. This includes installation instructions, flow charts, subroutine model documentation, and sample output files. The ROCCID program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can be easily added. The analysis models in ROCCID can account for the influences of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

Muss, J. A.↗
NASA NTRS2006

Critical Issues in the History of Spaceflight

At a May 1981 "Proseminar in Space History"held at the Smithsonian Institution's National Air and Space Museum (NASM) in Washington, DC, historians came together to consider the state of the discipline of space history. It was an historic occasion. The community of scholars interested in the history of spaceflight was not large; previously, well-meaning but untrained aficionados consumed with artifacts had dominated the field, to the exclusion of the larger context. At a fundamental level, this proseminar represented a "declaration of independence" for what might be called the "new aerospace history." In retrospect, it may be interpreted as marking the rise of space history as a recognizable subdiscipline within the field of U.S. history. Bringing together a diverse collection of scholars to review the state of the art in space history, this proseminar helped in a fundamental manner to define the field and to chart a course for future research. Its participants set about the task of charting a course for collecting, preserving, and disseminating the history of space exploration within a larger context of space policy and technology. In large measure, the course charted by the participants in this 1981 proseminar aided in advancing a very successful agenda of historical research, writing, and understanding of space history. Not every research project has yielded acceptable results, nor can it be expected to do so, but the sum of the effort since 1981 has been impressive. The opportunities for both the exploration of space and for recording its history have been significant. Both endeavors are noble and aimed at the enhancement of humanity. Whither the history of spaceflight? Only time will tell. But there has been an emergent "new aerospace history" of which space history is a central part that moves beyond an overriding concern for the details of the artifact to emphasize the broader role of the spacecraft. More importantly, it emphasizes the whole technological system, including not just the vehicle but also the other components that make up the aerospace climate, as an integral part of the human experience. It suggests that many unanswered questions spur the development of flight and that inquisitive individuals seek to know that which they do not understand.

Dick, Steven J.↗
NASA NTRS2000

Performance of the OVERFLOW-MLP and LAURA-MLP CFD Codes on the NASA Ames 512 CPU Origin System

The shared memory Multi-Level Parallelism (MLP) technique, developed last year at NASA Ames has been very successful in dramatically improving the performance of important NASA CFD codes. This new and very simple parallel programming technique was first inserted into the OVERFLOW production CFD code in FY 1998. The OVERFLOW-MLP code's parallel performance scaled linearly to 256 CPUs on the NASA Ames 256 CPU Origin 2000 system (steger). Overall performance exceeded 20.1 GFLOP/s, or about 4.5x the performance of a dedicated 16 CPU C90 system. All of this was achieved without any major modification to the original vector based code. The OVERFLOW-MLP code is now in production on the inhouse Origin systems as well as being used offsite at commercial aerospace companies. Partially as a result of this work, NASA Ames has purchased a new 512 CPU Origin 2000 system to further test the limits of parallel performance for NASA codes of interest. This paper presents the performance obtained from the latest optimization efforts on this machine for the LAURA-MLP and OVERFLOW-MLP codes. The Langley Aerothermodynamics Upwind Relaxation Algorithm (LAURA) code is a key simulation tool in the development of the next generation shuttle, interplanetary reentry vehicles, and nearly all "X" plane development. This code sustains about 4-5 GFLOP/s on a dedicated 16 CPU C90. At this rate, expected workloads would require over 100 C90 CPU years of computing over the next few calendar years. It is not feasible to expect that this would be affordable or available to the user community. Dramatic performance gains on cheaper systems are needed. This code is expected to be perhaps the largest consumer of NASA Ames compute cycles per run in the coming year.The OVERFLOW CFD code is extensively used in the government and commercial aerospace communities to evaluate new aircraft designs. It is one of the largest consumers of NASA supercomputing cycles and large simulations of highly resolved full aircraft are routinely undertaken. Typical large problems might require 100s of Cray C90 CPU hours to complete. The dramatic performance gains with the 256 CPU steger system are exciting. Obtaining results in hours instead of months is revolutionizing the way in which aircraft manufacturers are looking at future aircraft simulation work. Figure 2 below is a current state of the art plot of OVERFLOW-MLP performance on the 512 CPU Lomax system. As can be seen, the chart indicates that OVERFLOW-MLP continues to scale linearly with CPU count up to 512 CPUs on a large 35 million point full aircraft RANS simulation. At this point performance is such that a fully converged simulation of 2500 time steps is completed in less than 2 hours of elapsed time. Further work over the next few weeks will improve the performance of this code even further.The LAURA code has been converted to the MLP format as well. This code is currently being optimized for the 512 CPU system. Performance statistics indicate that the goal of 100 GFLOP/s will be achieved by year's end. This amounts to 20x the 16 CPU C90 result and strongly demonstrates the viability of the new parallel systems rapidly solving very large simulations in a production environment.

Taft, James R.↗
NASA NTRS2004

Detecting the Sun in 2-Gyr Old Open Clusters

The aim of this observation was to take advantage of the large collecting area and sensitivity of the European Space Agency's XMM-Newton telescope to survey the X ray brightness of solar-mass stars in the 2 Gyr old NGC 752 cluster in order to chart out the dependence of coronal X ray emission of Sun like stars as a function of age. Dr. Simon's stated role as one of the co-investigators in the project was limited to assisting the project's European Principal Investigator with the analysis and interpretation of the X ray measurements, and to assist in summarizing the results for publication. The observation was executed successfully, and approximately 130 X ray sources were detected in the XMM field of view and subsequently measured to obtain X ray count rates. To date neither the measurements nor the raw data have been distributed by the European P.I. to the co-investigators, It is expected that the measurements will be distributed to the co-investigators by the end of 2004, and once that is done, the scientific analysis by Dr. Simon can then begin. At present, since the data and measurements have not been shared with the co-investigators, there are no results to report.

Simon, Theodore↗
NASA NTRS1976

LOGSIM programmer's manual

A programmer's manual is reported for a Logic Simulator (LOGSIM) computer program that is a large capacity event simulator with the capability to accurately simulate the effects of certain unknown states, rise and fall times, and floating nodes in large scale metal oxide semiconductor logic circuits. A detailed description of the software with flow charts is included within the report.

Mitchell, C. L.↗
NASA NTRS1974

State space representations of distributed fluid line dynamics

The purpose of this paper is to demonstrate the convenience of using a systematic straight forward procedure to obtain meaningful dynamic information for a class of complex distributed parameter fluid line networks. System transients in the time domain are determined by means of state space techniques. Digital computer implementation yields a simple but consistent way of obtaining overall system time solutions. A step-by-step analysis procedure flow chart is shown in Appendix I which illustrates the basic approach for modeling, approximating and selecting digital techniques for simulating the dynamic response of fluid line systems.

Yao, H.↗
NASA NTRS2011

Analytical Approach in DeCoM

There are many papers on describing a LHP as an overall system, but few detail on the condenser section of a loop heat pipe. The DeCoM (Deepak Condenser Model) method utilizes user set initial parameters in-order to simulate a condenser by calculating the interactions between the fluid and the wall. Equations are derived for two sections of the condenser: a two-phase section and a subcooled (liquid) section. All Equations are based upon the conservation of energy theory, from which fluid temperature, and fluid quality values are solved. In order to solve for the heat transfer value, between fluid and the wall in two phase section, the Lockhart-Martinelli correlation method was implemented as a solution approach. For Liquid phase, the Reynolds number was used in-order to differentiate the flow state, from either turbulent or laminar, and Nusselt number was used to solve for the film coefficient. To represent these calculations for both sections a flow chart is presented in order to display the execution process of DeCoM. The benefit of DeCoM is that it is capable of performing preliminary analysis without requiring a license and without much of users knowledge on condensers.

Patel, Deepak↗
NASA NTRS1991

Data systems and computer science space data systems: Onboard memory and storage

The topics are presented in viewgraph form and include the following: technical objectives; technology challenges; state-of-the-art assessment; mass storage comparison; SODR drive and system concepts; program description; vertical Bloch line (VBL) device concept; relationship to external programs; and backup charts for memory and storage.

Shull, Tom↗
NASA NTRS1972

Air-sea interaction in the tropical Pacific Ocean

Charts of 3-month sea surface temperature (SST) anomalies in the eastern tropical Pacific Ocean were produced for the period 1949 to 1970. The anomalies along the United States and South American west coasts and in the eastern tropical Pacific appeared to be oscillating in phase during this period. Similarly, the satellite-derived cloudiness for each of four quadrants of the Pacific Ocean (130 deg E to 100 deg W, 30 deg N to 25 deg S) appeared to be oscillating in phase. In addition, a global tropical cloudiness oscillation from 30 deg N to 30 deg S was noted from 1965 to 1970, by using monthly satellite television nephanalyses. The SST anomalies were found to have a good degree of correlation both positive and negative with the following monthly geophysical parameters: (1) satellite-derived cloudiness, (2) strength of the North and South Pacific semipermanent anticyclones, (3) tropical Pacific island rainfall, and (4) Darwin surface pressure. Several strong direct local and crossequatorial relationships were noted. In particular, the high degree of correlation between the tropical island rainfall and the SST anomalies (r = +0.93) permitted the derivation of SST's for the tropical Pacific back to 1905. The close occurrence of cold tropical SST and North Pacific 700-mb positive height anomalies with central United States drought conditions was noted.

Allison, L. J.↗
NASA NTRS1991

MPD thruster technology

Inhouse magnetoplasmadynamic (MPD) thruster technology is discussed. The study focussed on steady state thrusters at powers of less than 1 MW. Performance measurement and diagnostics technologies were developed for high power thrusters. Also developed was a MPD computer code. The stated goals of the program are to establish: performance and life limitation; influence of applied fields; propellant effects; and scaling laws. The presentation is mostly through graphs and charts.

Myers, Roger M.↗
NASA NTRS1972

Attitude stability and performance of a dual-spin satellite with nutation damping.

Previous work of Anand and al. (1969) on the effect of aerodynamic torques on the steady-state behavior of a slowly spinning satellite without damping is extended to consideration of the effects of external torques and of a nutational damper on the transient and state motions of a satellite. Both the transient and steady-state behaviors are analyzed, and the attitude errors relative to a fixed star are established. The results indicate that, in the case of a particular satellite to be used for charting X-ray emitting sources in the celestial sphere, the effect of a nutational damper on the accuracy of the charting computations is significant.

Anand, D. K.↗
NASA NTRS2006

Physiologic Responses to Motorized and Non-Motorized Locomotion Utilizing the International Space Station Treadmill

Treadmill locomotion is used onboard the International Space Station (ISS) as a countermeasure to the effects of prolonged weightlessness. The treadmill operates in two modes: motorized (T-M) and non-motorized (T-NM). Little is known about the potential physiologic differences between modes which may affect countermeasure exercise prescription. PURPOSE: To quantify heart rate (HR), oxygen consumption (VO2), perceived exertion (RPE), and blood lactate (BLa) during T-M and T-NM locomotion at 2 and 4 mph in normal ambulatory subjects. METHODS: Twenty subjects (10 men, 10 women; 31+/-5 yr, 172+/-10 cm, 68+/-13 kg, mean SD) with a treadmill peakVO2 of 45.5+/-5.4 ml/kg/min (mean+/-SD) exercised on the ground-based ISS treadmill. Following a familiarization session in each mode, subjects completed two data collection sessions, T-M and T-NM in random order, at 2 and 4 mph. Subjects attempted to complete 5 min of exercise at each speed; if they could not maintain the speed, the trial was discontinued. At least 5 minutes of rest separated each speed trial, and at least 48 hrs separated each session. VO2 was measured continuously (metabolic gas analysis), while HR (HR monitor) and RPE (Borg Chart, 6-20 scale) were recorded each min. Not all subjects completed 5 min during each condition, therefore the mean of the min 3 and 4 was taken as representative of steady-state. BLa was measured (finger stick) within 2 min post-exercise. Paired t-tests were used to test for differences (p<0.05) between treadmill modes within the same speed. RESULTS: All twenty subjects completed at least 4 min of exercise during all conditions, except T-NM 4 mph when only 11 subjects completed the minimum exercise duration. VO2, HR, RPE and BLa were significantly higher during T-NM locomotion at both speeds.

Smith, Cassie↗
NASA NTRS1961

ANALYSIS OF CRYOGENIC PROPELLANT FEED SYSTEMS FOR ELECTROTHERMAL ENGINES.

An analytical investigation was made of the problems associated with the long-term storage and control of flow of cryogenic propellants for electrothermal engines. Storage of 35 to 174 pounds of propellant for three years is made difficult by the high ratio of surface area to storage tank volume, and the resulting high rate of heat leak. Vented and non-vented storage, storage as high pressure gas, and the use of refrigeration were considered. Recommended storage methods are: for ethane and ammonia vented storage - by venting propellant stored in excess of mission requirements; for hydrogen and helium - by non-vented storage of cold supercritical vapor; and for methane by storage as a non-vented two-phase mixture. The optimum propellant density in the storage tank and optimum insulation thickness were also determined. Design charts were developed for hydrogen and helium, for estimating the maximum pressure expected in non-vented storage tanks, as function of mission requirements. Separation of the constituent phases of liquid-vapor mixtures is achieved by throttling the two-phase mixture to a lower pressure (and temperature) and vaporizing the liquid in the mixture by heat exchange with the contents of the storage tank. The time limitations for continuous use of this method are discussed. Linde super insulations SI-44 or SI -91 are recommended for insulation. Precooling the insulation to temperatures below the steady state level with cold helium vapor before or during fueling of the storage tank eliminates the flow of heat to the tank contents during countdown and take-off. The masses, sizes, and power requirements of the recommended systems are low. The controls are simple and reliable. From the equations and charts in this report the components of the system for a particular mission can be sized. Recommendations are given for experimental work required for the development and testing of such components.

ELECTROTHERMAL ENGINE↗