Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “met”

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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Technical prospects for commercial and residential distribution and utilization of hydrogen

Various investigators have assumed that hydrogen will be compatible with conventional gas delivery systems and that, with minor modifications, hydrogen can be utilized in existing equipment for heating and cooking. The paper addresses some of the issues of concern in the compatibility of natural gas systems with hydrogen and hydrogen mixtures and identifies areas for which tests, research, or development are appropriate. Requirements to be met by atmospheric burners built for most commercial and residential gas appliances are discussed. Expected modifications to appliances for satisfactory operation with hydrogen are closing the primary air shutters, replacing the burners, adjusting the appliance gas regulator for proper delivery pressure, and possibly replacing the gas regulator or its vent.

Pangborn, J.↗
NASA NTRS1976

Simulation of obstacle detection scheme for Mars terrain using minicomputer

Simulation for detection of obstacles on Martian terrain by a laser rangefinder mounted on an autonomous roving vehicle is achieved by a rapid estimation scheme on a computer with IDIIOM display. Near and far edges of pyramids and hemispherical craters or boulders can be recognized if the obstacles are more than about 15 m from the laser rangefinder and the noise standard deviation is less than about 10 cm. If these conditions are not met the rapid estimation scheme can still detect the top edge of a boulder and the near edge of a crater. The scheme is considered equivalent or better than an earlier (Reed, Sanyal, and Shen, 1974) four-directional Laplacian method, but requires slightly more computation.

Leung, K. L.↗
NASA NTRS1977

Performance tests of two precision attitude determination systems

Results of laboratory performance tests of two satellite attitude determination systems are given. One system employed a strapdown star tracker and gyro assembly, the other a single axis, gimballed star tracker and a gyro assembly. The laboratory tests simulated those orbit conditions which would be experienced on a three axis stabilized, earth pointed satellite in geosynchronous orbit. A ground-fixed laboratory test was performed in which system axes remained stationary in the laboratory coordinates while revolving star beams stimulated the star trackers. The laboratory instrumentation techniques used to meet the stringent accuracy requirements are described. Results are presented which show both systems met the performance goal of 3.6 arc seconds. Comparative analyses of both systems are also discussed.

Mcaloon, K. J.↗
NASA NTRS1977

An ancient divergence among the bacteria

The 16S ribosomal RNZs from two species of met methanogenic bacteria, the mesophile Methanobacterium ruminantium and the thermophile Methanobacterium thermoautotrophicum, have been characterized in terms of the oligonucleotides produced by digestion with T1 ribonuclease. These two organisms are found to be sufficiently related that they can be considered members of the same genus or family. However, they bear only slight resemblance to 'typical' Procaryotic genera; such as Escherichia, Bacillus and Anacystis. The divergence of the methanogenic bacteria from other bacteria may be the most ancient phylogenetic event yet detected - antedating considerably the divergence of the blue green algal line for example, from the main bacterial line.

Balch, W. E.↗
NASA NTRS1977

National geodetic satellite program, part 1

The major accomplishments of the GEOS-B, C-band systems project is assessed. The project objectives are given, namely: (1) primary objectives that must be met for project success; (2) secondary objectives that were sufficiently important to warrant serious consideration; and (3) other objectives that were important to the project and for which additional effort would be desirable. The primary objectives are presented and discussed in detail.

Belgin, J.↗
NASA NTRS1977

Performance and emissions of a catalytic reactor with propane, diesel, and Jet A fuels

Tests were made to determine the performance and emissions of a catalytic reactor operated with propane, No. 2 diesel, and Jet A fuels. A 12-cm diameter and 16-cm long catalytic reactor using a proprietary noble metal catalyst was operated at an inlet temperature of 800 K, a pressure of 300,000 Pa and reference velocities of 10 to 15 m/s. No significant differences between the performance of the three fuels were observed when 98.5 percent purity propane was used. The combustion efficiency for 99.8-percent purity propane tested later was significantly lower, however. The diesel fuel contained 135 ppm of bound nitrogen and consequently produced the highest NOx emissions of the three fuels. As much as 85 percent of the bound nitrogen was converted to NOx. Steady-state emissions goals based on half the most stringent proposed automotive standards were met when the reactor was operated at an adiabatic combustion temperature higher than 1350 K with all fuels except the 99.8-percent purity propane. With that fuel, a minimum temperature of 1480 K was required.

Anderson, D. N.↗
NASA NTRS1977

The utility of short wavelength (1mm) remote sensing techniques for the monitoring and assessment of hydrologic parameters

Remote sensing programs that respond to the requirements of the water resources management and hydrologic communities are reviewed. The major areas where the needs of water resources management are being met involve the mapping and monitoring of snowcovered areas, hydrologic landuse, and surface water area. In the case of snowcovered area mapping the transfer of technology process is now being accomplished in the Western United States in a cooperative effort involving 6 federal agencies and 3 state agencies along with NASA. A new collaborative effort of the U.S. Army Corps of Engineers and NASA involves the mapping of landuse by Landsat and its use in hydrologic engineering watershed models employed in flood control/waterworks planning, design, and management. Improved systems planned for implementation in the 1978-1981 time frame can be expected to result in increased utilization of visible and near infrared remote sensing observations.

Rango, A.↗
NASA NTRS1977

Atmospheric density models

An atmospheric model developed by Jacchia, quite accurate but requiring a large amount of computer storage and execution time, was found to be ill-suited for the space shuttle onboard program. The development of a simple atmospheric density model to simulate the Jacchia model was studied. Required characteristics including variation with solar activity, diurnal variation, variation with geomagnetic activity, semiannual variation, and variation with height were met by the new atmospheric density model.

Mueller, A. C.↗
NASA NTRS1976

Water hyacinths for upgrading sewage lagoons to meet advanced wastewater treatment standards, part 2

Field tests using water hyacinths as biological filtration agents were conducted in the Mississippi gulf coast region. The plants were installed in one single cell and one multiple cell sewage lagoon systems. Water hyacinths demonstrated the ability to maintain BOD5 and total suspended solid (TSS) levels within the Environmental Protection Agency's prescribed limits of 30 mg/lBOD5 and 30 mg/l TSS. A multiple cell sewage lagoon system consisting of two aerated and one water hyacinth covered cell connected in series demonstrated the ability to maintain BOD5 and TSS levels below 30 mg/l year-round. A water hyacinth covered lagoon with a surface area of 0.28 hectare containing a total volume of 6.8 million liters demonstrated the capacity to treat 437,000 to 1,893,000 liters of sewage influent from 2.65 hectares of aerated lagoons daily and produce an effluent that met or exceeded standards year-round.

Wolverton, B. C.↗
NASA NTRS1978

Space Shuttle Proximity Operation Sensor Study

The performance of the Kuband radar was analyzed in detail, and the performance was updated and summarized. In so doing, two different radar design philosophies were described, and the corresponding differences in losses were enumerated. The resulting design margins were determined for both design philosophies and for both the designated and nondesignated range modes of operation. In some cases, the design margin was about zero, and in other cases it was significantly less than zero. With the point of view described above, the recommended solution is to allow more scan time but at the present scan rate. With no other changes in the present configuration, the radar met design detection specifications for all design philosophies at a range of 11.3 nautical miles.

Weber, C. L.↗
NASA NTRS1978

Site dependent factors affecting the economic feasibility of solar powered absorption cooling

A procedure was developed to evaluate the cost effectiveness of combining an absorption cycle chiller with a solar energy system. A basic assumption of the procedure is that a solar energy system exists for meeting the heating load of the building, and that the building must be cooled. The decision to be made is to either cool the building with a conventional vapor compression cycle chiller or to use the existing solar energy system to provide a heat input to the absorption chiller. Two methods of meeting the cooling load not supplied by solar energy were considered. In the first method, heat is supplied to the absorption chiller by a boiler using fossil fuel. In the second method, the load not met by solar energy is net by a conventional vapor compression chiller. In addition, the procedure can consider waste heat as another form of auxiliary energy. Commercial applications of solar cooling with an absorption chiller were found to be more cost effective than the residential applications. In general, it was found that the larger the chiller, the more economically feasible it would be. Also, it was found that a conventional vapor compression chiller is a viable alternative for the auxiliary cooling source, especially for the larger chillers. The results of the analysis gives a relative rating of the sites considered as to their economic feasibility of solar cooling.

Bartlett, J. C.↗
NASA NTRS1978

Study of hypersonic propulsion/airframe integration technology

An assessment is done of current and potential ground facilities, and analysis and flight test techniques for establishing a hypersonic propulsion/airframe integration technology base. A mach 6 cruise prototype aircraft incorporating integrated Scramjet engines was considered the baseline configuration, and the assessment focused on the aerodynamic and configuration aspects of the integration technology. The study describes the key technology milestones that must be met to permit a decision on development of a prototype vehicle, and defines risk levels for these milestones. Capabilities and limitations of analysis techniques, current and potential ground test facilities, and flight test techniques are described in terms of the milestones and risk levels.

Hartill, W. R.↗
NASA NTRS1978

Utilization requirements. A southern California Gas Company project SAGE report: Utilization requirements

Utilization requirements are given and comparisons made of two phase III SAGE (solar assisted gas energy) installations in California: (1) a retrofit installation in an existing apartment building in El Toro, and (2) an installation in a new apartment building in Upland. Such testing in the field revealed the requirements to be met if SAGE-type installations are to become commercially practical on a widespread basis in electric and gas energy usage.

Barbieri, R. H.↗
NASA NTRS1978

An Improved Version of the NASA-Lockheed Multielement Airfoil Analysis Computer Program

An improved version of the NASA-Lockheed computer program for the analysis of multielement airfoils is described. The predictions of the program are evaluated by comparison with recent experimental high lift data including lift, pitching moment, profile drag, and detailed distributions of surface pressures and boundary layer parameters. The results of the evaluation show that the contract objectives of improving program reliability and accuracy have been met.

Brune, G. W.↗
NASA NTRS1978

Simplified sonic-boom prediction

Sonic boom overpressures and signature duration may be predicted for the entire affected ground area for a wide variety of supersonic airplane configurations and spacecraft operating at altitudes up to 76 km in level flight or in moderate climbing or descending flight paths. The outlined procedure relies to a great extent on the use of charts to provide generation and propagation factors for use in relatively simple expressions for signature calculation. Computational requirements can be met by hand-held scientific calculators, or even by slide rules. A variety of correlations of predicted and measured sonic-boom data for airplanes and spacecraft serve to demonstrate the applicability of the simplified method.

Carlson, H. W.↗
NASA NTRS1975

Identification and promulgation of objectives for OAST R and T programs, Task 2

Overall perspectives and guidelines are discussed for defining and promulgating NASA's Office of Aeronautics and Space Technology (OAST) objectives to meet national needs and goals in aeronautical, space, and nuclear technology. Emphasis is placed on the practicality of ultimately instituting objective-setting processes within the normal OAST operation, and of establishing quantitative measures to be used as a working management tool in determining the degree to which the objectives have been or are being met.

Source record↗
NASA NTRS1978

Integrated source and channel encoded digital communication system design study

The particular Ku-band carrier, PN despreading, and symbol synchronization strategies, which were selected for implementation in the Ku-band transponder aboard the orbiter, were assessed and evaluated from a systems performance viewpoint, verifying that system specifications were met. A study was performed of the design and implementation of tracking techniques which are suitable for incorporation into the Orbiter Ku-band communication system. Emphasis was placed on maximizing tracking accuracy and communication system flexibility while minimizing cost, weight, and system complexity of Orbiter and ground systems hardware. The payload communication study assessed the design and performance of the forward link and return link bent-pipe relay modes for attached and detached payloads. As part of this study, a design for a forward link bent-pipe was proposed which employs a residual carrier but which is tracked by the existing Costas loop.

Alem, W. K.↗
NASA NTRS1978

Preliminary design study of an alternate heat source assembly for a Brayton isotope power system

Results are presented for a study of the preliminary design of an alternate heat source assembly (HSA) intended for use in the Brayton isotope power system (BIPS). The BIPS converts thermal energy emitted by a radioactive heat source into electrical energy by means of a closed Brayton cycle. A heat source heat exchanger configuration was selected and optimized. The design consists of a 10 turn helically wound Hastelloy X tube. Thermal analyses were performed for various operating conditions to ensure that post impact containment shell (PICS) temperatures remain within specified limits. These limits are essentially satisfied for all modes of operation except for the emergency cooling system for which the PICS temperatures are too high. Neon was found to be the best choice for a fill gas for auxiliary cooling system operation. Low cycle fatigue life, natural frequency, and dynamic loading requirements can be met with minor modifications to the existing HSA.

Strumpf, H. J.↗