Search NASA⌕ Search

SEARCH · Search NASA

Results for “wire array”

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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

CubeSats, Communication Satellites, and Outer Planet Science Satellites all share one thing in common: Mission success depends on maintaining power in the harsh space environment. For a vast majority of satellites, spacecraft power is sourced by a photovoltaic (PV) array system. Built around PV cells, the array systems also include wiring, substrates, connectors, and protection diodes. Each of these components must function properly throughout the mission in order for power production to remain at nominal levels. Failure of even one component can lead to a crippling loss of power. To help ensure PV array systems do not suffer failures on-orbit due to the space environment, NASA's Marshall Space Flight Center (MSFC) has developed a wide ranging test and evaluation capability. Key elements of this capability include: Testing: a. Ultraviolet (UV) Exposure b. Charged Particle Radiation (Electron and Proton) c. Thermal Cycling d. Plasma and Beam Environments Evaluation: a. Electrostatic Discharge (ESD) Screening b. Optical Inspection and easurement c. PV Power Output including Large Area Pulsed Solar Simulator (LAPSS) measurements This paper will describe the elements of the space environment which particularly impact PV array systems. MSFC test capabilities will be described to show how the relevant space environments can be applied to PV array systems in the laboratory. A discussion of MSFC evaluation capabilities will also be provided. The sample evaluation capabilities offer test engineers a means to quantify the effects of the space environment on their PV array system or component. Finally, examples will be shown of the effects of the space environment on actual PV array materials tested at MSFC.

Schneider, Todd A.↗
DOE OSTI2019

Generation of Terahertz Radiation in Magnetic Junctions Based on Nanowires

A system of spin-injection emitters employing magnetic junctions based on an array of parallel nanodimensional wires has been studied. Manufacturing technology and possible variants of the nanowire structure are discussed. Conditions of the formation of a new type of spin-injection emitters of terahertz radiation on this basis are considered. The design of the experimental setup is described, and the results of experiments are analyzed. It is established that signals in a 16–18 THz range can be generated by passing high-density current through the proposed nanowire array.

42 ENGINEERING↗
DOE OSTI2017

Stability of compression of the inner array plasma in nested arrays

The implosion of nested fiber/wire arrays was studied experimentally at the Angara-5-1 facility. The outer array consisted of kapron fibers, while the inner array was made of tungsten wires. The experiments were carried out at a discharge current of 3 MA. Stable compression of the inner array plasma was achieved by increasing the number of fibers in the outer array. In this case, a compact Z-pinch formed at the array axis. Near the pinch, no trailing plasma produced from the high-Z material of the inner array and capable of scattering and reradiating X-ray photons was observed. The trailing edge of the X-ray pulse was found to shorten in the absence of the trailing plasma around the pinch.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2004

Thermopile Detector Arrays for Space Science Applications

Thermopile detectors are widely used in uncooled applications where small numbers of detectors are required, particularly in low-cost commercial applications or applications requiring accurate radiometry. Arrays of thermopile detectors, however, have not been developed to the extent of uncooled bolometer and pyroelectric/ferroelectric arrays. Efforts at JPL seek to remedy this deficiency by developing high performance thin-film thermopile detectors in both linear and two-dimensional formats. The linear thermopile arrays are produced by bulk micromachining and wire bonded to separate CMOS readout electronic chips. Such arrays are currently being fabricated for the Mars Climate Sounder instrument, scheduled for launch in 2005. Progress is also described towards realizing a two-dimensional thermopile array built over CMOS readout circuitry in the substrate.

Foote, M. C.↗
DOE OSTI2025

Magnetic Solitons and Thickness‐Dependent Magnetization Reversal in Interconnected Helical Nanowire Arrays

By expanding magnetic nanostructures into the third dimension, it is possible to introduce new interactions and realize new forms of magnetic textures and emergent phenomena. Consequently, this unlocks new opportunities for applications in data storage, unconventional computing and sensing by utilizing 3D devices with enhanced functionalities. Connected magnetic nanowires offer a unique platform for applications such as neuromorphic computing due to their tunability and the presence of multiple transport pathways. However to realize this promise, it is necessary to further our understanding of how to locally control the magnetization in 3D, nanowire-based geometries. In this work we show the formation of magnetic domain walls, vortices, anti-vortices, and linked vortex-anti-vortex pairs in interconnected helical nanowire arrays. We show how wire diameter and 3D geometric design can control the states that form and reveal the magnetization reversal mechanism. Hence, we demonstrate this to be a highly tunable system, where the magnetization can be readily reconfigured by an external magnetic field.

3D Nanomagnetism↗
DOE OSTI2019

Tile-and-trim micro-resonator array fabrication optimized for high multiplexing factors

We present a superconducting micro-resonator array fabrication method that is scalable and reconfigurable and has been optimized for high multiplexing factors. The method uses uniformly sized tiles patterned on stepper photolithography reticles as the building blocks of an array. We exhibit this technique on a 101-element microwave kinetic inductance detector (MKID) array made from a titanium-nitride superconducting film. Characterization reveals 1.5% maximum fractional frequency spacing deviations caused primarily by material parameters that vary smoothly across the wafer. Yet, local deviations demonstrate a Gaussian distribution in fractional frequency spacing with a standard deviation of 2.7 × 10 -3 . We exploit this finding to increase the yield of the BLAST-TNG 250 μm production wafer by placing resonators in the array close in both physical and frequency space. This array consists of 1836 polarization-sensitive MKIDs wired in three multiplexing groups. We present the array design and show that the achieved yield is consistent with our model of frequency collisions and is comparable to what has been achieved in other low temperature detector technologies.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Physics Considerations for a Harp System Design at the Second Target Station of the Spallation Neutron Source

A harp system is being developed for monitoring proton beam profile direct upstream of the proton beam window at the Second Target Station of the Spallation Neutron Source, Oak Ridge National Laboratory. It consists of two sensor planes which have arrays of thin conducting wires aligned vertically and horizontally, respectively. It monitors beam profiles in two transverse directions to the beam axis by measuring the net-charge depositions in the sensor wires, which are caused by ejection of secondary electrons and delta rays driven by electromagnetic interactions with high energy protons. The net charge deposition in a sensing wire linearly correlates with the number of incident protons on it. This correlation is perturbed when the wire interacts with secondary electrons and delta rays originating from beam matter interactions in neighboring wires, PBW and residual gases. In this paper, we analyze the physical phenomena that affects the measurement uncertainties of the harp using particle transport simulations.

Lee, Yong Joong [ORNL] (ORCID:0000000298381723)↗
NASA NTRS1977

Nuclear Science Symposium, 23rd, Scintillation and Semiconductor Counter Symposium, 15th, and Nuclear Power Systems Symposium, 8th, New Orleans, La., October 20-22, 1976, Proceedings

The volume includes papers on semiconductor radiation detectors of various types, components of radiation detection and dosimetric systems, digital and microprocessor equipment in nuclear industry and science, and a wide variety of applications of nuclear radiation detectors. Semiconductor detectors of X-rays, gamma radiation, heavy ions, neutrons, and other nuclear particles, plastic scintillator arrays, drift chambers, spark wire chambers, and radiation dosimeter systems are reported on. Digital and analog conversion systems, digital data and control systems, microprocessors, and their uses in scientific research and nuclear power plants are discussed. Large-area imaging and biomedical nucleonic instrumentation, nuclear power plant safeguards, reactor instrumentation, nuclear power plant instrumentation, space instrumentation, and environmental instrumentation are dealt with. Individual items are announced in this issue.

Wagner, L. J.↗
NASA NTRS1978

Investigation of turbulent diffusion in the extreme lower atmosphere

Turbulent diffusion in the extreme lower layer of the atmosphere (up to 5 m) has been investigated. Turbulent flow was simulated under dry, stable and calm conditions by means of a 3.04 m diameter fan installed at a field site situated on flat grassland. The ambient wind was continuously monitored by means of a cup anemometer placed outside the wake, and the temperature distribution was measured by four thermometers placed on an 18 m tower, also outside the wake. Balloons and red smoke were used to visualize the wake flow and investigate the predominant sizes of turbulent eddies and their streamwise behavior. The mean and turbulent velocities along the turbulence line were measured using an array of hot-wire anomometers. Results provide substantial verification of a recently proposed model (Koper and Sadeh, 1975; Koper et al., 1978) relating the Lagrangian to the Eulerian turbulent velocity autocorrelation. In this model the Lagrangian autocorrelation is given by a domain integral over a set of ordinary Eulerian autocorrelations acquired simultaneously at all points within the flow field in question, which is viewed as a turbulence 'box'.

Koper, C. A., Jr.↗
NASA NTRS1984

Fracture behavior in silicon

The fracture mechanics of crystalline Si are reviewed, together with known techniques for minimizing the occurences of fracture and/or their effects. The fracture toughness (Kic) of Si varies only 10 percent from cell-to-cell and standard values have been established for different types of crystalline Si cells. A critical flaw size of 10-100 microns has been identified, and also pertains to polycrystalline materials. Chemical polishing is known to double the value of Kic, while edge rounding has no effect. Internal stresses, particularly those caused during ribbon growth, do not exceed 10 percent of Kic. External stresses are imposed by the module hardware and the ambient environment. Multiple contacts reduce the effects of cell fracture and series-parallel wiring in modules in arrays ameliorates the effects of single-cell failures. During manufacturing, maintenance of quality control and removal of sheets displaying aberrations can, depending on the costs and the implementation of the array reliability features, result in arrays delivering any desired level of reliability.

Leipold, M. H.↗
NASA NTRS1987

Bow-tie antennas on a dielectric half-space - Theory and experiment

A new formulation is discussed for the rigous calculation of the radiation pattern of a bow-tie antenna of finite length and infinitesimal thickness, placed on a lossless dielectric substrate. The analysis is based on a representation of the current density on the metal surface of the antenna as a sum of an imposed (quasistatic) term and a set of current modes with unknown amplitudes. Free-space fields that are expressed in terms of continuous spectra of symmetrized plane waves are matched to the current modes using the method of moments. The resulting set of equations are solved for the unknown current amplitudes. The calculations show that for increasing bow length the antenna impedance spirals rapidly to a value predicted by transmission line theory. The theory also shows that the E-plane pattern of a two-wavelength, 60-deg bow-tie antenna is dominated by low-loss current modes propagating at the dielectric wavenumber. As the bow tie narrows, the loss of the modes increases, and the dominant wavenumber tends to the quasi-static value. Pattern measurements made at 94 GHz are shown to agree well with theoretical predictions. Measurements for a long-wire antenna, a linear array of bow-tie elements, and a log-periodic antenna are also presented.

Compton, Richard C.↗
NASA NTRS1988

Effects of excitation level on the stability of an axisymmetric mixing layer

The effect of various levels of excitation on the stability and development of an axisymmetric mixing layer was studied experimentally. The flow was excited axisymmetrically by a single speaker placed at the base of the plenum chamber. Measurements of mean and phase-averaged velocity profiles were made using an array of hot-wire probes. The measured profiles were compared to eigenfunctions calculated from linear, viscous stability theory. It is shown that the theoretical predictions, based on measured profiles of mean velocity, compare very well with the phase-averaged measurements, even when the local disturbance reaches levels as high as 24 percent of the jet speed. The cumulative effect of excitation on the mean flow is examined as a function of local Strouhal number as well as excitation level.

Samet, M. M.↗
NASA NTRS1994

Influence of Turbulence Parameters, Reynolds Number, and Body Shape on Stagnation-Region Heat Transfer

The purpose of the present work was threefold: (1) to determine if a free-stream turbulence length scale existed that would cause the greatest augmentation in stagnation-region heat transfer over laminar levels; (2) to investigate the effect of velocity gradient on stagnation-region heat transfer augmentation by free-stream turbulence; and (3) to develop a prediction tool for stagnation heat transfer in the presence of free-stream turbulence. Heat transfer was measured in the stagnation region of four models with elliptical leading edges that had ratios of major to minor axes of 1:1, 1.5:1, 2.25:1, and 3:1. Five turbulence-generating grids were fabricated; four were square mesh, biplane grids made from square bars. The fifth grid was an array of fine parallel wires that were perpendicular to the model spanwise direction. Heat transfer data were taken at Reynolds numbers ranging from 37 000 to 228 000. Turbulence intensities were in the range of 1.1 to 15.9% while the ratio of integral length scale to leading-edge diameter ranged from 0.05 to 0.30. Stagnation-point velocity gradient was varied by nearly 50%. Stagnation-region heat transfer augmentation was found to increase with decreasing length scale but no optimum length scale was found. Heat transfer augmentation due to turbulence was found to be unaffected by the velocity gradient near the leading edge. A correlation was developed that fit heat transfer data for the square-bar grids to within +/- 4%.

Vanfossen, G. James↗
NASA NTRS1995

Fundamental phenomena on fuel decomposition and boundary-layer combustion processes with applications to hybrid rocket motors

The experimental study on the fundamental processes involved in fuel decomposition and boundary-layer combustion in hybrid rocket motors is continuously being conducted at the High Pressure Combustion Laboratory of The Pennsylvania State University. This research will provide a useful engineering technology base in the development of hybrid rocket motors as well as a fundamental understanding of the complex processes involved in hybrid propulsion. A high-pressure, 2-D slab motor has been designed, manufactured, and utilized for conducting seven test firings using HTPB fuel processed at PSU. A total of 20 fuel slabs have been received from the Mcdonnell Douglas Aerospace Corporation. Ten of these fuel slabs contain an array of fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. Diagnostic instrumentation used in the test include high-frequency pressure transducers for measuring static and dynamic motor pressures and fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. The ultrasonic pulse-echo technique as well as a real-time x-ray radiography system have been used to obtain independent measurements of instantaneous solid fuel regression rates.

Kuo, Kenneth K.↗
NASA NTRS1997

Reliability Investigation of Ball Grid Array Assemblies for Space Flight Applications

JPL, in a partnership with an industrial consortium, is currently engaged in the investigation of reliability and quality issues if ball grid array (BGA) packages as they may be applied to space flight electronics. Performing tests to determine the solder joint reliability of assemblies using BGAs under temperature cycling has proved to be a real challenge for test engineers.

Ball grid array printed wiring assemblies reliabil↗
NASA NTRS2007

Cryogenic Detector Technology for Space Science Application

We review the current status of detector development at NASA's Goddard Space Flight Center and address future prospect for space science application. In particular, the IR detector capability and applicability to second generation SOFIA instrument will be discussed. We will examine areas such as 3-dimensional hybridization of large format bolometer arrays to readout multiplexers; advanced light coupling scheme for planar ortho-mode transducer circuitry; integration of high density readout wiring for low temperature detector arrays; and microwave multiplexers for large format superconducting detector arrays.

Ting-Wen, Hsieh↗
NASA NTRS2011

Kilopixel X-Ray Microcalorimeter Arrays for Astrophysics: Device Performance and Uniformity

We are developing kilo-pixel arrays of TES microcalorimeters to enable high-resolution X-ray imaging spectrometers for future X-ray observatories and laboratory astrophysics experiments. Our current array design was targeted as a prototype for the X-ray Microcalorimeter Spectrometer proposed for the International X-ray Observatory, which calls for a 40x40-pixel core array of 300 micron devices with 2.5 e V energy resolution (at 6 keV). Here we present device characterization of our 32x32 arrays, including X-ray spectral performance of individual pixels within the array. We present our results in light of the understanding that our Mo/Au TESs act as weak superconducting links, causing the TES critical current (Ic) and transition shape to oscillate with applied magnetic field (B). We show Ic(B) measurements and discuss the uniformity of these measurements across the array, as well as implications regarding the uniformity of device noise and response. In addition, we are working to reduce pixel-to-pixel electrical and thermal crosstalk; we present recent test results from an array that has microstrip wiring and an angle-evaporated Cu backside heatsinking layer, which provides Cu coverage on the four sidewalls of the silicon wells beneath each pixel.

Eckart, M. E.↗
NASA NTRS2015

Electric Sail Propulsion for Exploring Nearby Interstellar Space

An Electric Sail is a revolutionary propellant-less propulsion system that is ideal for deep space missions to the outer planets, the Heliopause, and beyond. It is revolutionary in that it uses momentum exchange with the hypersonic solar wind to propel a spacecraft within the heliosphere. The momentum exchange is affected by the deflection of charged solar wind particles by an array of electrically biased wires that extend outward up to 30 km from a slowly rotating spacecraft. A high-voltage, positive bias on the wires, which are oriented normal to the solar wind flow, deflects the streaming protons, resulting in a reaction force on the wires that is also directed radially away from the sun. Over a period of months, this small force can accelerate the spacecraft to enormous speeds-on the order of 100-150 km/s (approximately 20 to 30 AU/yr). Unlike solar sails, Electric Sails do not rely on a fixed area to produce thrust. In fact, as they move away from the Sun and solar wind pressure decreases, the area for solar proton momentum transfer becomes larger, increasing system efficiency. As a result, thrust decreases at ≈1/r**(7/6) instead of the ≈1/r**2 rate typical for solar sails. The net effect is that an increased radial range of operation, together with increased thrust, both contribute to higher velocities and shorter total trip times to distant destinations. The MSFC Advanced Concepts Office (ACO) was awarded a Phase II NASA Innovative Advanced Concepts (NIAC) study to mature the technology for possible future demonstration and implementation. Preliminary results indicate that the physics of the system is viable and that a spacecraft propelled by an Electric Sail could reach the Heliopause in less than 15 years - and could be developed within a decade.

Johnson, Les↗