Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “bill”

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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Narrowband lidar technique for sodium temperature and Doppler wind observations of the upper atmosphere

A new two-frequency lidar for measuring mesospheric Na temperature profiles is described that uses a stabilized CW single-mode dye laser oscillator (rms frequency jitter less than 1 MHz) followed by a pulsed dye power amplifier (140 MHz FWHM linewidth) that is pumped by an injection-locked Nd:YAG laser. The laser oscillator is tuned to the two operating freqencies by observing the Doppler-free structure of the Na D2 fluorescence spectrum in a vapor cell. The lidar technique and initial observations of the temperature profile between 82 and 102 km at Ft. Collins, CO are described. Absolute temperature accuracies at the Na layer peak of better than + or - 3 K with a vertical resolution of 1 km and an integration period of approximately 5 min were achieved in this initial experiment. Finally, a multiple frequency technique for the simultaneous measurement of both temperature and Doppler wind profiles is discussed.

Bills, Richard E.↗
NASA NTRS1991

Effects of alcohol on pilot performance in simulated flight

Ethyl alcohol's known ability to produce reliable decrements in pilot performance was used in a study designed to evaluate objective methods for assessing pilot performance. Four air carrier pilot volunteers were studied during eight simulated flights in a B727 simulator. Total errors increased linearly and significantly with increasing blood alcohol. Planning and performance errors, procedural errors and failures of vigilance each increased significantly in one or more pilots and in the group as a whole.

Billings, C. E.↗
NASA NTRS1990

Development of experimental facilities for processing metallic crystals in orbit

This paper discusses the evolution, current status, and planning for facilities to exploit the microgravity environment of earth orbit in applied metallic materials science. Space-Shuttle based facilities and some precursor flight programs are reviewed. Current facility development programs and planned Space Station furnace capabilities are described. The reduced gravity levels available in earth orbit allow the processing of metallic materials without the disturbing influence of gravitationally induced thermal convection, stratification due to density differences in sample components, or the effects of hydrostatic pressure.

Duncan, Bill J.↗
NASA NTRS1991

The automatic human

An overview is presented of the growth and role of automation in civil aircraft operations for both cockpit management and ground control. NASA has initiated a research program centered on furthering automation and developing a consistent and rational philosophy of human centered aircraft and air traffic control automation. Introduction of the NASA Aviation Safety Reporting System (ASRS) has proved successful in bringing together pilots and ground controllers to report incidents of operational anomalies that can then be analyzed, leading to corrective action to prevent similar reoccurrences. Attention is given to the growing trend of extensive automation in the cockpit that appears to be leading to a diminution of management control of the aircraft by the decreasing number of flight crew members. A majority of reports indicate that there is a serious mismatch between new aircraft capabilities and ATC procedures, which were designed for older aircraft. ASRS has also kept research oriented toward real problems and community needs.

Billings, Charles↗
NASA NTRS1991

Dumbo: A pachydermal rocket motor

A brief historical account is given of the Dumbo nuclear reactor, a type of folded flow reactor that could be used for rocket propulsion. Much of the information is given in viewgraph form. Viewgraphs show details of the reactor system, fuel geometry, and key characteristics of the system (folded flow, use of fuel washers, large flow area, small fuel volume, hybrid modulator, and cermet fuel).

Kirk, Bill↗
NASA NTRS1991

Army Research Concerns in Engine Sealing

The Army Propulsion Directorate is primarily concerned with small engine technology, where sealing performance is most critical. Tip leakage and secondary flow losses have a much greater performance impact on small engine aero-components than on large engines. A brief survey and critique of presently employed sealing concepts is presented. Some recent new research thrusts that show promise for substantial improvement are discussed. An especially promising approach for small engine applications is brush seals. Brush seal concepts are being considered for outer air seal and secondary airflow system seal locations.

Bill, Robert C.↗
NASA NTRS1992

A combined Earth scanner and momentum wheel for attitude determination and control of small spacecraft

In order to satisfy the stringent cost and power requirements of small satellites, an advanced SCANWHEEL was designed, built, and qualified by ITHACO, Inc. The T-SCANWHEEL is a modular momentum/reaction wheel with an integral conical Earth scanner. The momentum wheel provides momentum bias and control torques about the pitch axis of a spacecraft. An angled scan mirror coupled to the rotating shaft of the momentum wheel provides a conical scan of the field-of-view of an infrared sensor to provide pitch-and-roll attitude information. By using the same motor and bearings for the momentum wheel and Earth scanner, the overall power consumption is reduced and the system reliability is enhanced. The evolution of the T-SCANWHEEL is presented, including design ground rules, tradeoff analyses, and performance results.

Bialke, Bill↗
NASA NTRS1992

Complex three-dimensional internal flows in the ASRM and RSRM aft end segments

Results from computational fluid dynamic analyses for complex three dimensional flows in the Advanced Solid Rocket Motor (ASRM) and Redesigned Solid Rocket Motor (RSRM) are presented. In particular, a parametric study for the case of a gimballed nozzle in these motors at various burn times and gimbal angles is presented. The resultant pressure fields are used to determine the location of the center of pressure and hinge moments due to the internal flow of these geometries.

Reske, Edward J.↗
NASA NTRS1992

Object linking in repositories

This topic is covered in three sections. The first section explores some of the architectural ramifications of extending the Eichmann/Atkins lattice-based classification scheme to encompass the assets of the full life cycle of software development. A model is considered that provides explicit links between objects in addition to the edges connecting classification vertices in the standard lattice. The second section gives a description of the efforts to implement the repository architecture using a commercially available object-oriented database management system. Some of the features of this implementation are described, and some of the next steps to be taken to produce a working prototype of the repository are pointed out. In the final section, it is argued that design and instantiation of reusable components have competing criteria (design-for-reuse strives for generality, design-with-reuse strives for specificity) and that providing mechanisms for each can be complementary rather than antagonistic. In particular, it is demonstrated how program slicing techniques can be applied to customization of reusable components.

Eichmann, David↗
NASA NTRS1992

Image processing mini manual

The intent is to provide an introduction to the image processing capabilities available at the Langley Research Center (LaRC) Central Scientific Computing Complex (CSCC). Various image processing software components are described. Information is given concerning the use of these components in the Data Visualization and Animation Laboratory at LaRC.

Matthews, Christine G.↗
NASA NTRS1992

First Lunar Outpost crew module thermal protection design sensitivity

A thermal protection study was conducted on the first lunar outpost (FLO) crew module. The study objectives are as follows: (1) assess effects of vehicle size on aerothermodynamic environment and thermal protection system (TPS) weight; (2) assess effects of lunar-return strategies on aerothermodynamic environment and TPS weight; and (3) assess weight penalty for common TPS design for all lunar-return strategies. All material is covered in viewgraph format.

Bouslog, Stan↗
NASA NTRS1992

Plume induced environments on future lunar mission vehicles

The objective of this presentation is to identify potential plume heating/impingement problem areas on vehicles used for future lunar missions. This is accomplished by comparison with lunar module plume investigations performed during 1968-1971. All material is presented in viewgraph format.

Rochelle, Bill↗
NASA NTRS1992

Solar probe power systems concepts

Some of the design options under consideration for providing on-board electric power for the Solar Probe Mission are discussed. Five spacecraft configurations were evaluated with slightly different power demands and volumetric constraints on the power system. This resulted in three different baseline power system designs to satisfy the five spacecraft configurations. These three current baseline power system designs use modified general-purpose heat source (GPHS) radioisotope thermoelectric generators (RTGs) similar to those launched on the Galileo and Ulysses spacecraft. The modular RTG currently under development and testing is a potential advanced alternative to the current baseline GPHS-RTG technology design.

Nesmith, Bill J.↗
NASA NTRS1990

The NASA Space Life Sciences Training Program - Preparing the way

Attention is given to the goals and methods adopted in the NASA Space Life Sciences Training Program (SLSTP) for preparing scientists and engineers for space-related life-sciences research and operations. The SLSTP is based on six weeks of projects and lectures which give an overview of payload processing and experiment flow in the space environment. The topics addressed in the course of the program include descriptions of space vehicles, support hardware, equipment, and research directions. Specific lecture topics include the gravity responses of plants, mission integration of a flight experiment, and the cardiovascular deconditioning. The SLSTP is shown to be an important part of the process of recruiting and training qualified scientists and engineers to support space activities.

Biro, Ronald↗
NASA NTRS1991

Recent manufacturing advances for spiral bevel gears

The U.S. Army Aviation Systems Command (AVSCOM), through the Propulsion Directorate at NASA Lewis Research Center, has recently sponsored projects to advance the manufacturing process for spiral bevel gears. This type of gear is a critical component in rotary-wing propulsion systems. Two successfully completed contracted projects are described. The first project addresses the automated inspection of spiral bevel gears through the use of coordinate measuring machines. The second project entails the computer-numerical-control (CNC) conversion of a spiral bevel gear grinding machine that is used for all aerospace spiral bevel gears. The results of these projects are described with regard to the savings effected in manufacturing time.

Handschuh, Robert F.↗
NASA NTRS1992

Venus - Satellite orbital decay, ephemeral ring formation, and subsequent crater production

The question of whether most or even all of the observed impact features on the surface of Venus can be derived from satellitic material is addressed. Consideration is given to the hypothesis that the craters retained on the surface of Venus were all emplaced within a relatively short interval, as collisional fragments of a former satellite impacted the surface. It is concluded that the areal density of craters may provide no absolute age information at all: the craters may be as recent as the last significant satellite loss event.

Bills, Bruce G.↗
NASA NTRS1992

Voyager 2 ultraviolet spectrometer solar occultations at Neptune - Constraints on the abundance of methane in the stratosphere

The study compares Voyager 2 ultraviolet spectrometer (UVS) solar occultation lightcurves at wavelengths 125-138 nm acquired during the Neptune encounter with 1D methane photochemical transport models. For the p-T models under consideration, acceptable fits to the UVS lightcurves are obtained with eddy mixing coefficient values (K sub 1/2) near the half-light altitudes of 2-15 x 10 exp 6 sq cm/s (ingress) and 4-35 x 10 exp 6 sq cm/s (egress) and lower stratospheric methane mixing ratio values of 5-100 x 10 exp -5. For the nominal p-T models and a criterion based on replicating the spacing in altitude of the 125-138 nm UVS lightcurves, K sub 1/2 values of 10 exp 7 sq cm/s (ingress) and 1-2 x 10 exp 7 sq cm/s (egress) and methane mixing ratios of about 0.0004 (ingress and egress) are indicated.

Bishop, James↗