Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “source configuration”

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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Ion beam treatment of potential space materials at the NASA Lewis Research Center

Ion source systems in different configurations, have been used to generate unique morphologies for several NASA space applications. The discharge chamber of a 30 cm ion source was successfully used to texture potential space radiator materials for the purpose of obtaining values of thermal emittance greater than 0.85 at 700 and 900 K. High absorptance surfaces were obtained using ion beam seed texturing, for space radiator materials that were flown on the Long Duration Exposure Facility (LDEF) for 5.8 years in space. An ion source discharge chamber was also used to develop electrode surfaces with suppressed secondary electron emission characteristics for use in collectors in microwave amplifier traveling wave tubes. This was accomplished by sputtering textured carbon onto copper as well as texturing copper using tantalum and molybdenum as sacrificial texture inducing seeding materials. In a third configuration, a dual ion beam system was used to generate high transmittance diamondlike carbon (DLC) films.

Kussmaul, Michael↗
DOE OSTI2016

Multi-particle inspection using associated particle sources

Disclosed herein are representative embodiments of methods, apparatus, and systems for performing combined neutron and gamma ray radiography. For example, one exemplary system comprises: a neutron source; a set of alpha particle detectors configured to detect alpha particles associated with neutrons generated by the neutron source; neutron detectors positioned to detect at least some of the neutrons generated by the neutron source; a gamma ray source; a set of verification gamma ray detectors configured to detect verification gamma rays associated with gamma rays generated by the gamma ray source; a set of gamma ray detectors configured to detect gamma rays generated by the gamma ray source; and an interrogation region located between the neutron source, the gamma ray source, the neutron detectors, and the gamma ray detectors.

42 ENGINEERING↗
DOE OSTI2023

Core-Pedestal Plasma Configurations in Advanced Tokamaks

Here, several configurations for the core and pedestal plasma are examined for a predefined tokamak design by implementing multiple heating/current drive (H/CD) sources to achieve an optimum configuration of high fusion power in a noninductive operation while maintaining an ideally magnetohydrodynamic (MHD) stable core plasma using the IPS-FASTRAN framework. IPS-FASTRAN is a component-based lightweight coupled simulation framework that is used to simulate magnetically confined plasma by integrating a set of high-fidelity codes to construct the plasma equilibrium (EFIT, TOQ, and CHEASE), calculate the turbulent heat and particle transport fluxes (TGLF), model various H/CD systems (TORIC, TORAY, GENRAY, and NUBEAM), model the pedestal pressure and width (EPED), and estimate the ideal MHD stability (DCON). The TGLF core transport model and EPED pedestal model are used to self-consistently predict plasma profiles consistent with ideal MHD stability and H/CD (and bootstrap) current sources. In order to evaluate the achievable and sustainable plasma beta, varying configurations are produced ranging from the no-wall stability to with-wall stability regimes, simultaneously subject to the self-consistent TGLF, EPED, and H/CD source profile predictions that optimize configuration performance. The pedestal density, plasma current, and total injected power are scanned to explore their impact on the target plasma configuration, fusion power, and confinement quality. A set of fully noninductive scenarios are achieved by employing ion-cyclotron, neutral beam injection, helicon, and lower-hybrid H/CDs to provide a broad profile for the total current drive in the core region for a predefined tokamak design. These noninductive scenarios are characterized by high fusion gain (Q ~ 4) and power (P fus ~ 600 MW), optimum confinement quality (H 98 ~ 1.1), and high bootstrap current fraction (f BS ~ 0.7) for Greenwald fraction below unity. The broad current profile configurations identified are stable to low-n kink modes either because the normalized pressure β N is below the no-wall limit or a wall is present.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

System for fast draining of an airfan heat exchanger and methods of using the same

A system for draining an airfan heat exchanger includes an airfan heat exchanger including a housing, a pressurized gas source fluidly coupled to the airfan heat exchanger and configured to hold a purging gas at a predetermined pressure, and a controller configured to control delivery of the purging gas to the airfan heat exchanger. The pressurized gas source is configured to provide a flow of the purging gas to the airfan heat exchanger and thereby drain water held in the airfan heat exchanger. The purging gas to the airfan will cause the airfan to drain quickly avoiding potential damage to the airfan from freezing of the water during cold weather.

Jahnke, Fred C.↗
DOE OSTI2017

Multiplication and Presence of Shielding Material from Time-Correlated Pulse-Height Measurements of Subcritical Plutonium Assemblies

Here, we present the results from the first measurements of the Time-Correlated Pulse-Height (TCPH) distributions from 4.5 kg sphere of α-phase weapons-grade plutonium metal in five configurations: bare, reflected by 1.27 cm and 2.54 cm of tungsten, and 2.54 cm and 7.62 cm of polyethylene. A new method for characterizing source multiplication and shielding configuration is also demonstrated. The method relies on solving for the underlying fission chain timing distribution that drives the spreading of the measured TCPH distribution. We found that a gamma distribution fits the fission chain timing distribution well and that the fit parameters correlate with both multiplication (rate parameter) and shielding material types (shape parameter). The source-to-detector distance was another free parameter that we were able to optimize, and proved to be the most well constrained parameter. MCNPX-PoliMi simulations were used to complement the measurements and help illustrate trends in these parameters and their relation to multiplication and the amount and type of material coupled to the subcritical assembly.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1987

Managing Development and Maintenance of Software

Source Management Utility (SMU) computer program is tool to manage development and maintenance of computer software. Its purpose to control organization of configured data sets containing source, object, and load-module files. Written in PL/1 and assembler.

Rook, Gerald W.↗
DOE OSTI2015

Integrated system for investigating sub-surface features of a rock formation

A system for investigating non-linear properties of a rock formation around a borehole is provided. The system includes a first sub-system configured to perform data acquisition, control and recording of data; a second subsystem in communication with the first sub-system and configured to perform non-linearity and velocity preliminary imaging; a third subsystem in communication with the first subsystem and configured to emit controlled acoustic broadcasts and receive acoustic energy; a fourth subsystem in communication with the first subsystem and the third subsystem and configured to generate a source signal directed towards the rock formation; and a fifth subsystem in communication with the third subsystem and the fourth subsystem and configured to perform detection of signals representative of the non-linear properties of the rock formation.

58 GEOSCIENCES↗
DOE OSTI2024

Embedded FPGA developments in 130 nm and 28 nm CMOS for machine learning in particle detector readout

Embedded field programmable gate array (eFPGA) technology allows the implementation of reconfigurable logic within the design of an application-specific integrated circuit (ASIC). This approach offers the low power and efficiency of an ASIC along with the ease of FPGA configuration, particularly beneficial for the use case of machine learning in the data pipeline of next-generation collider experiments. An open-source framework called "FABulous" was used to design eFPGAs using 130 nm and 28 nm CMOS technology nodes, which were subsequently fabricated and verified through testing. The capability of an eFPGA to act as a front-end readout chip was assessed using simulation of high energy particles passing through a silicon pixel sensor. A machine learning-based classifier, designed for reduction of sensor data at the source, was synthesized and configured onto the eFPGA. A successful proof-of-concept was demonstrated through reproduction of the expected algorithm result on the eFPGA with perfect accuracy. Finally, further development of the eFPGA technology and its application to collider detector readout is discussed.

47 OTHER INSTRUMENTATION↗
NASA NTRS1989

On the stability of a class of isothermal, magnetostatic atmospheres

The stability of a class of isothermal magnetostatic atmospheres with one ignorable coordinate corresponding to a uniform gravitational field in a plane geometry is explored. Special attention is given to the stability of nonpotential equilibria that have the same magnetic field geometry as the potential equilibrium of the solution family. It is found that equilibria in which the source currents for the potential field are buried at large distances below the photospheric base are stable. Also considered is the stability of configurations in which the source currents for the potential field are located at a finite depth below the base.

Webb, G. M.↗
NASA NTRS1979

Solar thermoelectric power generation for Mercury orbiter missions

Mercury orbiter mission study results have shown that conventional silicon solar cell array technology is not adequate to produce power because of expected temperatures which range from -90 C to +285 C in about 50 minutes for 16 sun eclipses/day. The solar thermoelectric generator (STG), which requires relatively high temperatures, is being developed as a replacement power source. Several thermoelectric technologies (i.e., lead telluride alloys, bismuth telluride, selenide, and silicon-germanium alloys have been examined for their suitability. Solar concentrator configurations (i.e., flat plate, Fresnel lens, mini-cone, and Cassegrain types) were also studied as candidates for increasing incident radiation during Mercury orbital operations. Detailed results are presented, and show that an STG design based on the use of silicon-germanium alloy thermoelectric material and using high-voltage thermopiles with individual miniconical concentrators presents the optimum combination of technology and configuration for minimizing power source mass.

Swerdling, M.↗
DOE OSTI2016

Layered shielding design for an active neutron interrogation system

The use of source and detector shields in active neutron interrogation can improve detector signal. In simulations, a shielded detector with a source rotated π/3 rad relative to the opening decreased neutron flux roughly three orders of magnitude. Several realistic source and detector shield configurations were simulated. A layered design reduced neutron and secondary photon flux in the detector by approximately one order of magnitude for a deuterium–tritium source. The shield arrangement can be adapted for a portable, modular design.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1993

Influence of test configuration on the combustion characteristics of polymers as ignition sources

The experimental evaluation of polymers as ignition sources for metals was accomplished at the NASA White Sands Test Facility (WSTF) using a standard promoted combustion test. These tests involve the transient burning of materials in high-pressure oxygen environments. They have provided data from which design decisions can be made; data include video recordings of ignition and non-ignition for specific combinations of metals and polymers. Other tests provide the measured compositions of combustion products for polymers at select burn times and an empirical basis for estimating burn rates. With the current test configuration, the detailed analysis of test results requires modeling a three-dimensional, transient convection process involving fluid motion, thermal conduction and convection, the diffusion of chemical species, and the erosion of sample surface. At the high pressure extremes, it even requires the analysis of turbulent, transient convection where the physics of the problem are not well known and the computation requirements are not practical at this time. An alternative test configuration that can be analyzed with a relatively-simple convection model was developed during the summer period. The principal change constitutes replacing a large-diameter polymer disk at the end of the metal test rod with coaxial polymer cylinders that have a diameter nearer to that of the metal rod. The experimental objective is to assess the importance of test geometries on the promotion of metal ignition by testing with different lengths of the polymer and, with an extended effort, to analyze the surface combustion in the redesigned promoted combustion tests through analytical modeling of the process. The analysis shall use the results of cone-calorimeter tests of the polymer material to model primary chemical reactions and, with proper design of the promoted combustion test, modeling of the convection process could be conveniently limited to a quasi-steady boundary layer analysis where the economical solution of parabolic equations is involved. The products for the summer period are: (1) a conceptual-level redesign of the test apparatus, and (2) the development and use of an approximate integral boundary layer analysis to demonstrate the influence of geometry changes prior to testing. A computer code STAN5, an accurate numerical boundary layer model whose earlier versions were developed for the NASA Lewis Research Center by the Fellow, also was installed and validated on the WSTF and New Mexico State University computer systems as a starting point in the development of a more detailed fluid mechanics and combustion model.

Julien, Howard L.↗
DOE OSTI2025

Strategies for the in-orbit gain tracking using the modulated X-ray sources for the Resolve microcalorimeter spectrometer on the X-ray Imaging and Spectroscopy Mission

Accurate and precise correction of the gain drift is the key to achieve the required energy resolution of the Resolve microcalorimeter spectrometer on the X-ray Imaging and Spectroscopy Mission (XRISM). Therefore, Resolve is equipped with highly configurable X-ray sources called the modulated X-ray source (MXS). The pulsed nature allows us to separate calibration and astrophysical X-rays by time interval selections. However, undesirable characteristics of the MXS, such as the afterglow X-rays, restrict the allowed configuration range. Moreover, the nonlinear and discontinuous behaviors of the calibration line count rate make the determination of the optimal setting highly complex. The MXS count rate model has been established using measurements in the spacecraft thermal vacuum test with the flight detector and MXS. A trade-off study using the model enables us to choose a few settings for the continuous use of the MXS optimized for different ranges of target gain tracking intervals. An alternative approach, where the MXS is used only intermittently, has also been developed and implemented. This new mode enables us to reconstruct the drift without having most of the undesirable effects in science data. This also forms the basis of the gain tracking under the current Resolve configuration with the closed gate valve.

Astronomy and AstroPhysics↗
DOE OSTI2017

Distributed gas detection system and method

A distributed gas detection system includes one or more hollow core fibers disposed in different locations, one or more solid core fibers optically coupled with the one or more hollow core fibers and configured to receive light of one or more wavelengths from a light source, and an interrogator device configured to receive at least some of the light propagating through the one or more solid core fibers and the one or more hollow core fibers. The interrogator device is configured to identify a location of a presence of a gas-of-interest by examining absorption of at least one of the wavelengths of the light at least one of the hollow core fibers.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Low-pressure hydrogen discharge maintenance in a large-size plasma source with localized high radio-frequency power deposition

The development of the two-dimensional fluid-plasma model of a low-pressure hydrogen discharge, presented in the study, is regarding description of the plasma maintenance in a discharge vessel with the configuration of the SPIDER source. The SPIDER source, planned for the neutral-beam-injection plasma-heating system of ITER, is with localized high RF power deposition to its eight drivers (cylindrical-coil inductive discharges) and a large-area second chamber, common for all the drivers. The continuity equations for the charged particles (electrons and the three types of positive ions) and for the neutral species (atoms and molecules), their momentum equations, the energy balance equations for electrons, atoms and molecules and the Poisson equations are involved in the discharge description. In addition to the local processes in the plasma volume, the surface processes of particle reflection and conversion on the walls as well as for a heat exchange with the walls are included in the model. The analysis of the results stresses on the role of the fluxes (particle and energy fluxes) in the formation of the discharge structure. The conclusion is that the discharge behavior is completely obeyed to non-locality. The latter is displayed by: (i) maximum values of plasma parameters (charged particle densities and temperatures of the neutral species) outside the region of the RF power deposition, (ii) shifted maxima of the electron density and temperature, of the plasma potential and of the electron production, (iii) an electron flux, with a vortex structure, strongly exceeding the total ion flux which gives evidence of a discharge regime of non-ambipolarity and (iv) a spatial distribution of the densities of the neutral species resulting from their fluxes.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Load balancing for multi-beam additive manufacturing systems

As powder bed fusion (PBF) additive manufacturing (AM) becomes a more mature field, system configurations are gradually moving away from the classic single heat source, layer-by-layer system configurations towards unconventional system configurations that offer higher throughput. Higher throughput systems allow PBF systems to be considered for a larger variety of industrial applications. However, the inclusion of multiple heat sources, or beams, also increases the complexity of the control schemes needed. For multi-beam systems with overlapping fields of view, the distribution of workload, or load balancing, across these beams directly affects the total print time for a build. Additionally, the probability of any beam failing in a multi-beam system increases with the number of beams. While manual methods of load balancing and dealing with beam failures are reasonable for current generation multi-beam systems, as system configurations become more complex, manual methods will become prohibitively inefficient. Here, this paper introduces two different ways to load balance multi-beam systems of various configuration types, regardless of their complexity, which are highly performant. A consequence of this performance is the enablement of on-the-fly load balancing in the event a beam fails, thus improving system robustness.

36 MATERIALS SCIENCE↗