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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Greenhouse Gas Life Cycle Emissions Assessment Model (GLEAM) Model Documentation

The Greenhouse gas Life cycle Emissions Assessment Model (GLEAM) estimates life cycle greenhouse gas emissions from future scenarios of electricity generation considering a wide range of generation technologies. Building on the National Laboratory of the Rockies longstanding effort to quantify life cycle emissions by electricity generation technology under the LCA Harmonization Project, GLEAM streamlines the process of estimating cumulative greenhouse gas emissions on a life cycle basis. Given a set of inputs regarding annual installed and decommissioned generation capacity, as well as generation, GLEAM estimates the carbon dioxide equivalent emissions by year. The model also offers optional modules to decompose carbon dioxide equivalent emissions into constituent greenhouse gases (e.g., carbon dioxide, methane, and nitrous oxide) as well as estimate hydrogen leakage from relevant technologies. The results from GLEAM can be used to inform future electricity planning scenarios as well as investment or regulatory decisions.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS1972

Development and testing of a high cycle life 30 A-h sealed AgO-Zn battery

A two-phase program was initiated to investigate design parameters and technology to develop an improved AgO-Zn battery. The basic performance goal was 100 charge/discharge cycles (22 h/2 h) at 50 percent depth of discharge following a six-month period of charged stand at room temperature. Phase 1, cell evaluation, involved testing 70 cells in five-cell groups. The major design variables were active material ratios, electrolyte concentrations, separator systems, and negative plate shape. Phase 1 testing showed that cycle life could be improved 10 percent to 20 percent by using greater ratios of zinc to silver oxide and higher electrolyte concentrations. Wedge-shaped negatives increased cycle life by nearly 100 percent. Phase 2 battery evaluation, which was initiated before the Phase 1 results were known completely, involved evaluation of six designs as 19-cell batteries. Only one battery exceeded 100 cycles following nine months charged stand.

Bogner, R. S.↗
NASA NTRS1972

Preliminary design of an auxiliary power unit for the space shuttle. Volume 5: Selected system cycle performance data

Detailed cycle steady-state performance data are presented for the final auxiliary power unit (APU) system configuration. The selection configuration is a hydrogen-oxygen APU incorporating a recuperator to utilize the exhaust energy and using the cycle hydrogen flow as a means of cooling the component heat loads. The data are given in the form of computer printouts and provide the following: (1) verification of the adequacy of the design to meet the problem statement for steady-state performance; (2) overall system performance data for the vehicle system analyst to determine propellant consumption and hydraulic fluid temperature as a function for varying mission profiles, propellant inlet conditions, etc.; and (3) detailed component performance and cycle state point data to show what is happening in the cycle as a function of the external forcing functions.

Hamilton, M. L.↗
NASA NTRS1971

Optimal flash rate and duty cycle for flashing visual indicators.

This experiment examined the ability of observers to determine, as quickly as possible, whether a visual indicator was steadily on or flashing. Six flash rates (periods) were combined factorially with three duty cycles (on-off ratios) to define 18 ?types' of intermittent signals. Experimental sessions were divided into six runs of 100 trials, each run utilizing one of the six flash rates. On any given trial in a run, the probability of a steady signal occurring was 0.5 and the probability of a flashing signal occurring was 0.5. A different duty cycle was employed daily for each experimental session. In all, 400 trials were devoted to each of the flash rates at each duty cycle. Accuracy and latency of response were the dependent variables of interest. The results show that the observers view the light for an interval of time appropriate to the expected flash rate and duty cycle; whether they judge the light to be steady or intermittent depends upon whether the light is extinguished during the predetermined waiting period. Adoption of this temporal criterion delays responding in comparison to those tasks involving responses to light onset. The decision or response criteria held by the observers are also sensitive to the parameters of the flashing light: observers become increasingly willing to call a flashing light ?steady' as flash duration increases.

Markowitz, J.↗
NASA NTRS1972

New evidence for solar cycle variations at great distances

Recent studies of solar planetary relationships are directed toward exploring how far out from the sun one could observe solar cycle variations. A positive solar Jovian relationship is suggested from a Chree superposed epoch study of the intensity of the great red spot of Jupiter over a period of about six solar cycles. The characteristic double maxima observed in the solar cycle variation is common to other observations of solar events in the photosphere, chromosphere, and corona; radio and corpuscular emissions from the sun; cosmic ray intensity and geomagnetic activity. The same method of analysis adopted for the study of luminosity changes of the planets Jupiter, Saturn, Uranus, and Neptune indicates that the fluctuations of luminosity follow the single maximum solar cycle represented by sunspot numbers. In conjunction with changes of upper atmospheric density and temperature, it is suggested that the extreme ultraviolet (EUV) emission from the sun may be connected with luminosity changes. A method of distinguishing between phenomena related to solar wind and those related to solar EUV is presented.

Venkatesan, D.↗
NASA NTRS1974

Experimental transient vane temperatures in a cascade for gas stream temperature cycling between 922 and 1644 K (1200 and 2500 F)

Experimental transient turbine vane metal temperatures were obtained from tests conducted on air-cooled vanes installed in a four-vane cascade for a gas temperature cycled between 922 and 1644 K (1200 and 2500 F). Transient data were recorded by a high-speed data acquisition system. Temperatures at the same phase of each transient cycle were repeatable between cycles to within 11 kelvins (20 F), simulated cruise and idle steady-state readings were repeated by the cruise and idle readings taken from the ends of a transient half-cycle at low pressure to within 17 kelvins (30 F). The tests were conducted at pressure levels of 31 and 83 N-sq cm (45 and 120 psia) with coolant temperatures of 811 and 589 K (1000 and 600 F), respectively.

Gauntner, D. J.↗
NASA NTRS1974

The solar cycle variation of the solar wind helium abundance

A critical survey was made of the experimental evidence for a variation of the relative abundance by number h, (n alpha/np), of helium in the solar wind. The abundance is found to vary by delta h = 0.01 + or - 0.01 from 0.035 to 0.045 over solar cycle 20. Changes in the average bulk speed during the solar activity cycle was insufficient to account for this increase in h with the solar cycle. The slope of the linear relation between h and the plasma bulk speed is also found to vary, being greatest around solar maximum. An attempt is made to explain the 30% variation in h as the result of the variation in the number of major solar flares over a solar cycle. These obvious transients are apparently not numerous enough to explain the observed variation, but the reasonable expectation remains that the transients observed recently by Skylab which may occur more frequently than major flares could augment those associated with major flares. Since the solar wind flux is not observed to increase at solar maximum, the abundance of Helium cannot be proportional to the proton flux leaving the sun unless the solar wind comes from a smaller area of the sun at maximum than at minimum.

Ogilvie, K. W.↗
NASA NTRS1974

Evidence of solar-cycle variations in the solar wind

Solar-wind observations are presented from July 1965 through June 1971 that show the first evidence for long-term variations in the solar wind associated with changes in the solar-cycle. The observations indicate that the frequency of high-speed streams in the solar wind and their duration vary over the solar cycle. There are more days associated with high-speed streams during solar maximum than during solar minimum. The yearly average of the solar-wind speed varies over the solar cycle and is highest at solar maximum. These measurements also provide the first direct observational evidence for changes in the solar wind which can account for the solar-cycle modulation of the cosmic-ray intensity.

Intriligator, D. S.↗
NASA NTRS1975

Experimental transient turbine blade temperatures in a research engine for gas stream temperatures cycling between 1067 and 1567 k

Experimental transient turbine blade temperatures were obtained from tests conducted on air-cooled blades in a research turbojet engine, cycling between cruise and idle conditions. Transient data were recorded by a high speed data acquisition system. Temperatures at the same phase of each transient cycle were repeatable between cycles to within 3.9 K (7 F). Turbine inlet pressures were repeatable between cycles to within 0.32 N/sq cm (0.47 psia). The tests were conducted at a gas stream temperature of 1567 K (2360 F) at cruise, and 1067 K (1460 F) at idle conditions. The corresponding gas stream pressures were about 26.2 and 22.4 N/sq cm (38 and 32.5 psia) respectively. The nominal coolant inlet temperature was about 811 K (1000 F).

Gauntner, D. J.↗
NASA NTRS1975

Effect of thermal cycling in a Mach 0.3 burner rig on properties and structure of directionally solidified gamma/gamma prime - delta eutectic

Tensile and stress rupture properties at 1040 C of a thermally cycled gamma/gamma prime - delta eutectic were essentially equivalent to the as-grown properties. Tensile strength and rupture life at 760 C appeared to decrease slightly by thermal cycling. Thermal cycling resulted in gamma prime coarsening and Widmanstatten delta precipitation in the gamma phase. An unidentified precipitate, presumably gamma prime, was observed within the delta phase. The eutectic alloy exhibited a high rate of oxidation-erosion weight loss during thermal cycling in the Mach 0.3 burner rig.

Gray, H. R.↗
NASA NTRS1975

High-Temperature, Low-Cycle Fatigue of Copper-Base Alloys for Rocket Nozzles. Part 1: Data Summary for Materials Tested in Prior Programs

A more detailed analysis of the results obtained in 188 previously reported low-cycle fatigue tests of various candidate materials for regeneratively-cooled, reusable rocket nozzle liners was reported. Plots of load range versus cycles were reported for each test along with a stress-strain hysteresis loop near half-life. In addition, a summary table was provided to compare N5 (cycles to a five percent load range drop) and Nf (cycles to complete specimen separation) values for each test.

Conway, J. B.↗
NASA NTRS1976

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 4: Open recuperated and bottomed gas turbine cycles

Open-cycle recuperated gas turbine plant with inlet temperatures of 1255 to 1644 K (1800 to 2500 F) and recuperators with effectiveness values of 0, 70, 80 and 90% are considered. A 1644 K (2500 F) gas turbine would have a 33.5% plant efficiency in a simple cycle, 37.6% in a recuperated cycle and 47.6% when combined with a sulfur dioxide bottomer. The distillate burning recuperated plant was calculated to produce electricity at a cost of 8.19 mills/MJ (29.5 mills/kWh). Due to their low capital cost $170 to 200 $/kW, the open cycle gas turbine plant should see duty for peaking and intermediate load duty.

Amos, D. J.↗
NASA NTRS1976

Duration of diastole versus cycle length as correlates of left ventricular ejection time

Studies were done on 82 normal subjects to evaluate cycle length vs duration of diastole as determinants of left ventricular ejection time. Cycle length and its reciprocal, heart rate, had the highest correlation with left ventricular ejection time. Removal of the self-correlation of left ventricular ejection time within cycle length reduces the correlation so that, of all intervals, duration of diastole had the highest correlation as a determinant of left ventricular ejection time. Cycle length and heart rate remain valuable as spuriously close but not misleading correlates for predicting or correcting left ventricular ejection time.

Weisdorf, D.↗
NASA NTRS1977

Closed-cycle gas dynamic laser design investigation

A conceptual design study was made of a closed cycle gas-dynamic laser to provide definition of the major components in the laser loop. The system potential application is for long range power transmission by way of high power laser beams to provide satellite propulsion energy for orbit changing or station keeping. A parametric cycle optimization was conducted to establish the thermodynamic requirements for the system components. A conceptual design was conducted of the closed cycle system and the individual components to define physical characteristics and establish the system size and weight. Technology confirmation experimental demonstration programs were outlined to develop, evaluate, and demonstrate the technology base needed for this closed cycle GDL system.

Ketch, G. W.↗
NASA NTRS1976

A thermochemical data bank for cycle analysis

The use of a computer program PAC-2 to produce a thermodynamic data bank for various materials used in water splitting cycles is described. The sources of raw data and a listing of 439 materials for which data are available are presented. The use of the data bank in conjunction with two other programs, CEC-72 and HYDRGN, is also discussed. The integration of these three programs implement an evaluation procedure for thermochemical water splitting cycles. CEC-72 is a program used to predict the equilibrium composition of the various chemical reactions in the cycle. HYDRGN is a program which is used to calculate changes in thermodynamic properties, work of separation, amount of recycle, internal heat regeneration, total thermal energy, and process thermal efficiency for a thermochemical cycle.

Carty, R. H.↗
NASA NTRS1976

A thermochemical data bank for cycle analysis

The use of the computer program PAC-2 to produce a thermodynamic data bank for various materials used in water-splitting cycles is described. The sources of raw data and a listing of 439 materials for which data are presently available are presented. This paper also discusses the use of the data bank in conjunction with two other programs, CEC-72 and HYDRGN. The integration of these three programs implement an evaluation procedure for thermochemical water splitting cycles. CEC-72 is a program used to predict the equilibrium composition of the various chemical reactions in the cycle. HYDRGN is a program which is used to calculate changes in thermodynamic properties, work of separation, amount of recycle, internal heat regeneration, total thermal energy and process thermal efficiency for a thermochemical cycle.

Carty, R.↗
NASA NTRS1977

Cycle life characteristics of sealed silver-zinc cell with inorganic separator

Two batteries containing 18 cells have been cycling in a simulated synchronous (24-hour) orbit for over a year at 40% depth of discharge at 22 C. One battery is under individual cell monitoring and control and the other battery is controlled at the battery level. The battery with individual cell monitoring and protection has performed over 350 cycles with no sign of failure. The battery without individual cell protection failed at 270 cycles from failure to remain above the specified minimum discharge voltage. A significant conclusion is that the sealed Ag-Zn cells manufactured with the inorganic separator material have demonstrated their capability to cycle at a fairly high depth of discharge and are worthy of consideration in short life synchronous orbit applications.

Lear, J. W.↗
NASA NTRS1977

A life cycle cost economics model for projects with uniformly varying operating costs

A mathematical model is developed for calculating the life cycle costs for a project where the operating costs increase or decrease in a linear manner with time. The life cycle cost is shown to be a function of the investment costs, initial operating costs, operating cost gradient, project life time, interest rate for capital and salvage value. The results show that the life cycle cost for a project can be grossly underestimated (or overestimated) if the operating costs increase (or decrease) uniformly over time rather than being constant as is often assumed in project economic evaluations. The following range of variables is examined: (1) project life from 2 to 30 years; (2) interest rate from 0 to 15 percent per year; and (3) operating cost gradient from 5 to 90 percent of the initial operating costs. A numerical example plus tables and graphs is given to help calculate project life cycle costs over a wide range of variables.

Remer, D. S.↗