Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “facets”

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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Parity breaking at faceted crystal growth fronts during ice templating

Directional solidification of water-based solutions has emerged as a versatile technique to template hierarchical porous materials, but this nonequilibrium process remains incompletely understood. Here, in this study, we use phase-field simulations to shed light on the mechanism that selects the growth direction of the lamellar ice structure that templates those materials. Our results show that this selection can be understood within the general framework of spontaneous parity breaking, yielding quantitative predictions for the tilt angle of lamellae with respect to the thermal axis. The results provide a theoretical basis to interpret a wide range of experimental observations.

Materials science↗
NASA NTRS1986

Application of NCOREL to conical multi-finned and multi-faceted configurations

A more versatile analytic conformal mapping approach for grid generation is implemented in a full potential supersonic flow code (NCOREL). Configurations such as multi-finned bodies and wings with vertical tails cannot be treated using a single conformal mapping transformation for grid generation. Instead, a series of analytic conformal mappings are used in progression to generate grids that are capable of resolving the complex multiple shock flow fields that exist about these configurations. Aplications of the grid generation techniques are presented for a variety of cross sections along with their conical full potential flow solutions.

Siclari, M. J.↗
NASA NTRS1986

Development of composite facets for the surface of a space-based solar dynamic concentrator

An account is given of the composite fabrication techniques envisioned for the production of mirror-quality substrates furnishing the specular reflectance required for the NASA Space Station's solar dynamic concentrator energy system. The candidate materials were graphite fiber-reinforced glass, aluminum, and polymer matrices whose surfaces would be coated with thin metal layers and with atomic oxygen degradation-inhibiting protective coatings to obtain the desired mirror surface. Graphite-epoxy mirror substrate samples have been found to perform satisfactorily for the required concentrator lifetime.

Ayers, Schuyler R.↗
NASA NTRS1988

Supercooling effects in faceted eutectic Nb-Si alloys

The effect of melt supercooling on the microstructure of an Nb-58 at. pct Si alloy is investigated experimentally using an electromagnetic levitation apparatus. It is found that, starting with an alloy nominally of eutectic composition, nucleation of Nb5Si3 occurs in the supercooled liquid first. Upon further cooling, the remaining liquid continues to supercool until the second phase, NbSi2 is nucleated, which is commonly accompanied by rapid recalescence. The primary phase exibits a eutectoid-type decomposition. The observations are discussed with reference to the results of quantitative microstructural measurements, compositional and thermal analysis, and preliminary thermodynamic modeling of the phase diagram.

Gokhale, A. B.↗
NASA NTRS1995

The many facets of auditory display

In this presentation we will examine some of the ways sound can be used in a virtual world. We make the case that many different types of audio experience are available to us. A full range of audio experiences include: music, speech, real-world sounds, auditory displays, and auditory cues or messages. The technology of recreating real-world sounds through physical modeling has advanced in the past few years allowing better simulation of virtual worlds. Three-dimensional audio has further enriched our sensory experiences.

Blattner, Meera M.↗
NASA NTRS2003

Investigating Morphological Stability of Faceted Interfaces with Axial Heat Processing (AHP) Technique

Successful processing of homogeneous semiconductor single crystals from their melts depends strongly on precise control of thermal and fluid flow conditions near the solid/liquid interface. In this project, we utilize a novel crystal growth technique called Axial Heat Processing (AHP) that uses a baffle, positioned inside the melt near the interface, to supply and/or conduct heat axially to the interface. The baffle, which may or may not have a heater encased in it, can promote more stable and planar growth as well as reduce buoyancy driven convection. The latter is because the baffle reduces the aspect ratio of the melt as it separates the melt into three sections, above the baffle, in the feed gap between the baffle and the crucible wall, and below the baffle between the baffle base and the interface. AHP also enables a close monitoring and/or control of thermal boundaries near the solid/liquid interface during crystal growth by means of thermocouples placed in the baffle. The interface is kept planar when a heating element in the baffle is used. However, a proper choice of melt height is necessary to keep the interface planar when using the baffle without a heater. This study addresses the influence of melt height and growth velocity on the segregation profile of AHP-grown Sb doped Ge single crystals.

Abbaschian, Reza↗
NASA NTRS2003

Facets and Challenges of Managing the Development of a $1 Billion Satellite

Contents include the folloving: Presidents budget. Office of Administrator chart. Aura project organization chart. Agreements. Aura observatory configuration. Aura science questions. EOS Aura atmospheric profile measurements. Science objectives: tracking ozone layer recovery; global measurements of air quality; impact of atmospheric constituente on climate. MLS instruments, OH measurement example. Osone monitoring instrument (OMI). OMI technology. OMI will track global ozone changes.

Loiacono, John↗
NASA NTRS1999

Development of the Facet Cryostat

A proof of concept prototype cryostat has been developed to demonstrate the ability to accommodate low temperature science investigations within the constraints of the Hitchhiker siderail carrier on the Space Shuttle.

space cryogenics cryostats superfluid helium neon↗