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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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31 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Investigations into mirror fabrication metrology analysis

This final report describes the work performed under this delivery order from June 1993 through August 1994. The scope of work included three distinct tasks in support of the AXAF-I program. The objective of the first task was to perform investigations of the grinding and polishing characteristics of the zerodur material by fabricating several samples. The second task was to continue the development of the integrated optical performance modeling software for AXAF-I. The purpose of third and final task was to develop and update the database of AXAF technical documents for an easy and rapid access. The MSFC optical and metrology shops were relocated from the B-wing of Building 4487 to Room BC 144 of Building 4466 in the beginning of this contract. This included dismantling, packing, and moving the equipment from its old location, and then reassembling it at the new location. A total of 65 zerodur samples, measuring 1 inch x 2 inches x 6 inches were ground and polished to a surface figure of lambda/10 p-v, and a surface finish of 5A rms were fabricated for coating tests. A number of special purpose tools and metal mirrors were also fabricated to support various AXAF-I development activities. In the metrology area, the ZYGO Mark 4 interferometer was relocated and also upgraded with a faster and more powerful processor. Surface metrology work was also performed on the coating samples and other optics using ZYGO interferometer and WYKO profilometer. A number of new features have been added to the GRAZTRACE program to enhance its analysis and modeling capabilities. A number of new commands have been added to the command mode GRAZTRACE program to provide a better control to the user on the program execution and data manipulation. Some commands and parameter entries have been reorganized for a uniform format. The command mode version of the convolution program CONVOLVE has been developed. An on-line help system and a user's manual have also been developed for the benefit of the users. The database of AXAF technical documents continues to progress. The titles, company name, date, and location of over 390 documents have been entered in this database. This database provides both a data search and retrieval function, and a data adding function. These functions allow a user to quickly search the data files for documents or add new information. A detailed user's guide has also been prepared. This user guide includes a document classification guide, a list of abbreviations, and a list of acronyms, which have been used in compiling this database of AXAF-I technical documents.

Dimmock, John O.↗
DOE OSTI2021

Methods for Evaluating DC Arc Incident Energy in PV Systems: Preprint

Renewable energy systems continue to be one of the fastest growing segments of the energy industry. This paper focuses on the understanding of how photovoltaic (PV) technology behaves under dc arc conditions. Emphasis is placed on the electrical safety aspect of DC arc flash incident energy evaluation. Because of the fast proliferation of PV systems and the lack of formal equivalent calculation guidelines such as IEEE 1584 for AC systems, it has been necessary to rely on different equations and models presented by various researchers over the last few years. This paper discusses the behavior of PV systems under arc conditions and presents the results of available methods to estimate the dc arc flash incident energy. This paper provides a comparative analysis of a proposed arc-flash incident energy calculation method against different laboratory tests including those performed by NREL. Detailed explanations are provided regarding the effect of PV module I-V and P-V curves under arcing conditions. Examples of the application of the proposed calculation method to the test measurements are included.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Materials Data on VP by Materials Project

VP1 is Tungsten Carbide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. V3+ is bonded to six equivalent P3- atoms to form a mixture of face, edge, and corner-sharing VP6 octahedra. The corner-sharing octahedral tilt angles are 45°. All V–P bond lengths are 2.40 Å. P3- is bonded to six equivalent V3+ atoms to form a mixture of distorted edge and corner-sharing PV6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on V3P by Materials Project

V3P crystallizes in the tetragonal P4_2/n space group. The structure is three-dimensional. there are three inequivalent V sites. In the first V site, V is bonded in a 4-coordinate geometry to four equivalent P atoms. There are a spread of V–P bond distances ranging from 2.37–2.45 Å. In the second V site, V is bonded in a 2-coordinate geometry to three equivalent P atoms. There are a spread of V–P bond distances ranging from 2.37–2.68 Å. In the third V site, V is bonded in a 2-coordinate geometry to two equivalent P atoms. There are one shorter (2.38 Å) and one longer (2.41 Å) V–P bond lengths. P is bonded in a 9-coordinate geometry to nine V atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on V2P by Materials Project

V2P is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent V sites. In the first V site, V is bonded in a 4-coordinate geometry to four equivalent P atoms. There are a spread of V–P bond distances ranging from 2.33–2.47 Å. In the second V site, V is bonded in a 5-coordinate geometry to five equivalent P atoms. There are a spread of V–P bond distances ranging from 2.44–2.67 Å. P is bonded in a 9-coordinate geometry to nine V atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VP by Materials Project

VP1 is Molybdenum Carbide MAX Phase-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. V3+ is bonded to six equivalent P3- atoms to form a mixture of distorted corner and edge-sharing VP6 pentagonal pyramids. All V–P bond lengths are 2.41 Å. P3- is bonded to six equivalent V3+ atoms to form a mixture of corner, edge, and face-sharing PV6 octahedra. The corner-sharing octahedral tilt angles are 47°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VP4 by Materials Project

VP4 is Sylvanite-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. V4+ is bonded to six P1- atoms to form edge-sharing VP6 octahedra. There are a spread of V–P bond distances ranging from 2.35–2.42 Å. There are two inequivalent P1- sites. In the first P1- site, P1- is bonded in a 4-coordinate geometry to one V4+ and three P1- atoms. There are two shorter (2.23 Å) and one longer (2.25 Å) P–P bond lengths. In the second P1- site, P1- is bonded in a 4-coordinate geometry to two equivalent V4+ and two P1- atoms. The P–P bond length is 2.22 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VP2 by Materials Project

P2V crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. V5+ is bonded in a 8-coordinate geometry to eight P+2.50- atoms. There are a spread of V–P bond distances ranging from 2.43–2.49 Å. There are two inequivalent P+2.50- sites. In the first P+2.50- site, P+2.50- is bonded in a 4-coordinate geometry to three equivalent V5+ and three equivalent P+2.50- atoms. There are one shorter (2.23 Å) and two longer (2.58 Å) P–P bond lengths. In the second P+2.50- site, P+2.50- is bonded in a 5-coordinate geometry to five equivalent V5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on V4P3 by Materials Project

V4P3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are five inequivalent V+2.25+ sites. In the first V+2.25+ site, V+2.25+ is bonded to six P3- atoms to form VP6 octahedra that share corners with six VP6 octahedra, corners with five equivalent VP5 square pyramids, corners with two equivalent VP5 trigonal bipyramids, edges with two equivalent VP6 octahedra, edges with three equivalent VP5 trigonal bipyramids, faces with two VP6 octahedra, and a faceface with one VP5 square pyramid. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–P bond distances ranging from 2.33–2.53 Å. In the second V+2.25+ site, V+2.25+ is bonded to five P3- atoms to form VP5 square pyramids that share corners with five equivalent VP6 octahedra, a cornercorner with one VP5 square pyramid, corners with six equivalent VP5 trigonal bipyramids, edges with two equivalent VP6 octahedra, edges with two equivalent VP5 square pyramids, edges with two equivalent VP5 trigonal bipyramids, and a faceface with one VP6 octahedra. The corner-sharing octahedra tilt angles range from 37–56°. There are a spread of V–P bond distances ranging from 2.35–2.42 Å. In the third V+2.25+ site, V+2.25+ is bonded to five P3- atoms to form VP5 trigonal bipyramids that share corners with four VP6 octahedra, corners with six equivalent VP5 square pyramids, edges with three equivalent VP6 octahedra, edges with two equivalent VP5 square pyramids, and edges with four equivalent VP5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 29–45°. There are a spread of V–P bond distances ranging from 2.42–2.46 Å. In the fourth V+2.25+ site, V+2.25+ is bonded in a square co-planar geometry to four P3- atoms. There are two shorter (2.40 Å) and two longer (2.49 Å) V–P bond lengths. In the fifth V+2.25+ site, V+2.25+ is bonded to six P3- atoms to form VP6 octahedra that share corners with eight equivalent VP6 octahedra, corners with four equivalent VP5 trigonal bipyramids, edges with two equivalent VP6 octahedra, edges with four equivalent VP5 square pyramids, and faces with two equivalent VP6 octahedra. The corner-sharing octahedra tilt angles range from 43–53°. There are a spread of V–P bond distances ranging from 2.35–2.48 Å. There are four inequivalent P3- sites. In the first P3- site, P3- is bonded in a 7-coordinate geometry to seven V+2.25+ atoms. In the second P3- site, P3- is bonded in a 8-coordinate geometry to eight V+2.25+ atoms. In the third P3- site, P3- is bonded to six V+2.25+ atoms to form distorted face-sharing PV6 pentagonal pyramids. In the fourth P3- site, P3- is bonded in a 6-coordinate geometry to six V+2.25+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on V5P3 by Materials Project

V5P3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent V sites. In the first V site, V is bonded in a 6-coordinate geometry to six equivalent P atoms. All V–P bond lengths are 2.46 Å. In the second V site, V is bonded in a 5-coordinate geometry to five equivalent P atoms. There are a spread of V–P bond distances ranging from 2.37–2.57 Å. P is bonded in a 9-coordinate geometry to nine V atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1946

Static-thrust Investigation of Full-scale PV-2 Helicopter Rotors Having NACA 0012.6 and 23012.6 Airfoil Sections

An investigation was conducted to compare the performance of two 25-ft-diam rotors which had identical dimensions and were similar in construction but different in blade airfoil-sections. Tests were conducted at indicated blade pitch angles from 3 degrees to 11.5 degrees and rotor speeds of 200, 290, and 371 rpm. The 23012.6 rotor required 2 percent less power to hover than the 0012.6. At thrust coefficients above design, the performance of the 23012.6 became better than the 0012.6 rotor.

PROPELLERS, HELICOPTER - P-V ENG FORUM 2↗