Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “LiP”

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 NTRS1988

InP homojunction solar cell performance on the LIPS 3 flight experiment

Performance data for the NASA Lewis Research Center indium phosphide n+p homojunction solar cell module on the LIPS 3 Flight Experiment is presented. The objective of the experiment is to measure the performance of InP cells in the natural radiation environment of the 1100 km altitude, 60+ deg inclination orbit. Analysis of flight data indicates that the performance of the four cells throughout the first year is near expected values. No degradation in short-circuit current was seen, as was expected from radiation tolerance studies of similar cells. Details of the cell structure and flight module design are discussed. The results of the temperature dependency and radiation tolerance studies necessary for normalization and analysis of the data are included.

Brinker, David J.↗
NASA NTRS1989

On-orbit results of the LIPS 3/InP homojunction solar cell experiment

The flight performance of the NASA indium phosphide homojunction cell module on the LIPS 3 satellite is presented. The experimental objectivewas to measure the InP cell performance in the natural radiation environment in a circular 1100 km altitude orbit inclined 60 degrees. Flight data for the first year is close to expected values. No degradation in the short-circuit current is seen. Details of cell structure and flight module design are discussed.

Brinker, David J.↗
NASA NTRS1990

Finite element analysis of structural components using viscoplastic models with application to a cowl lip problem

The viability of advanced viscoplastic models for nonlinear finite element analyses of structural components is investigated. Several uniaxial and a multiaxial problem are analyzed using the finite element implementation of Freed's viscoplastic model. Good agreement between the experimental and calculated uniaxial results validates the finite element implementation and gives confidence to apply it to more complex multiaxial problems. A comparison of results for a sample structural component (the cowl lip of a hypersonic engine inlet) with the earlier elastic, elastic-plastic, and elastic-plastic-creep analyses available in the literature shows that the elastic-viscoplastic analyses yield more reasonable stress and strain distributions. Finally, the versatility of the finite-element-based solution technology presented herein is demonstrated by applying it to another viscoplastic model.

Arya, V. K.↗
NASA NTRS1988

InP homojunction solar cell performance on the LIPS III flight experiment

Performance data for the NASA Lewis Research Center indium phosphide n+p homojunction solar cell module on the LIPS 3 flight experiment is presented. The objective of the experiment is to measure the performance of InP cells in the natural radiation environment of the 1100 km altitude, 60+ deg inclination orbit. Analysis of flight data indicates that the performance of the four cells throughout the first year is near expected values. No degradation in short-circuit current was seen, as was expected from radiation tolerance studies of similar cells. Details of the cell structure and flight module design are discussed. The results of the temperature dependency and radiation tolerance studies necessary for normalization and analysis of the data are included.

Brinker, David J.↗
NASA NTRS1991

Spaceflight performance of several types of silicon solar cells on the LIPS 3 satellite

Results from exposure of several types of Solarex silicon cells to a space environment for nearly two years on the LIPS 3 satellite are presented. Experiments include standard thickness (10 mil) cells with and without back surface fields, and ultrathin (2 mil) cells also with and without back surface fields. A comparison between a widely used coverslide adhesive, DC 93-500 and a potential alternate is also presented. The major findings from the data are that the 2 mil cells without a back surface field show the smallest normalized short circuit current degradation and that the 10 mil back surface field cells show the greatest absolute power output for the radiation exposures and temperatures encountered. The new encapsulant (McGhan Nusil CV-2500) exhibits a degradation comparable to DC 93-500. A comparison is made with each of the cell types in this experiment with expectations based on JPL Radiation Handbook data.

Silver, J.↗
NASA NTRS1990

Recent results from the InP homojunction cell module on the LIPS III spacecraft

The flight performance of the NASA Lewis Research Center's indium phosphide homojunction cell module on the LIPs III spacecraft is presented. Four n+-p diffused junction cells, an early product of an InP development program, were flown. The voltage range of the data prohibits determination of the open-circuit voltage or the maximum power point. However, analysis of the 32 months of short-circuit current data reveals a slight increase, not the 4 percent decrease expected from radiation tolerance studies. This increase may be due to continual cleaning of possible prelaunch dust contamination or changes in data acquisition system calibration. For all cells, the average short-circuit current remains below prelaunch values.

Brinker, David J.↗
NASA NTRS1991

Analysis of nozzle lip and backflow expansion of a small hydrazine thruster

Results are presented for computations made with the direct simulation Monte Carlo method for the expansion of the thick boundary layer of a small nozzle. The objective in the investigation is to assess the boundary-layer characteristics that most affect the flow properties of the expanding gas. In the computations, large degrees of species separation and thermal nonequilibrium are observed as the gas expands around the nozzle lip. These aspects of the flow indicate the necessity of treating the problem through a discrete particle approach. Assessment is made of the sensitivity of the calculated results to the form of the boundary layer initially assumed. It is found that the amount of backflow is related to the flow temperature close to the wall. Therefore, the opportunity presents itself for the reduction of the impingement potential of such thrusters through appropriate design considerations. Experimental procedures for verification of the type of computations undertaken in the current study are discussed. It is proposed that the calculations made in the backflow region offer the best opportunity.

Boyd, Iain D.↗
NASA NTRS1992

Lip leakage flow simulation for the Gravity Probe B gas spinup

The lip leakage flow for the Gravity Probe B (GP-B) gas spinup system is investigated using a particle simulation code on the Connection Machine (PSiCM). Particle simulation is employed because the flow conditions are in the transition regime between continuum and free molecule where particle methods are of greatest use. The dominant flow is Couette in nature and the simulation is first validated through comparison to theoretical results for Couette flow in the transition regime. A GP-B type geometry is then simulated and results are presented for two conditions, those corresponding to near the inlet and near the outlet of the spinup channel. Comparison to experiment is not made because experimental data is not yet available.

Dagum, Leonardo↗
NASA NTRS1951

Preliminary Investigation of a Translating Cowl Technique for Improving Take-off Performance of a Sharp-lip Supersonic Diffuser

A preliminary investigation was conducted in quiescent air on a translating cowl technique for improving the take-off performance of a sharp-lip supersonic diffuser. The technique consists of cutting the cowling in a plane normal to its axis and then translating the forepart of the cowling in the forward direction. The leading edge of the fixed portion of the cowling is rounded. Appreciable improved inlet performance was obtained with a cowling translation corresponding to a gap of only 1/4 inlet radius.

ENGINES, TURBOJET - PERFORMANCE↗
DOE OSTI2020

Materials Data on LiP(HO2)2 by Materials Project

LiH2PO4 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with two equivalent LiO4 tetrahedra and corners with four equivalent PO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.98–2.01 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent LiO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.51–1.61 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.04 Å) and one longer (1.53 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.65 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Li1+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one P5+, and one H1+ atom. In the third O2- site, O2- is bonded in a trigonal planar geometry to one Li1+, one P5+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one P5+ and two H1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiP(WO4)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiP(WO4)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗