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Results for “active processes”

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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At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

The failure mechanism of a nickel electrode in a nickel-hydrogen cell

Studies on a number of types of nickel electrodes after cycle failure in a Ni/H2 cell showed that the failure is due to the loss of high rate discharge capability rather than an absolute capacity loss. The failure mechanism is speculated to be a combination of migration of the active material away from the current collecting nickel sinter, increased porosity of the active material caused by cycling, and an electrical isolation process of the active material during discharge.

Lim, H. S.↗
NASA NTRS1972

Methods of measurement for semiconductor materials, process control, and devices

Activities directed toward the development of methods of measurement for semiconductor materials, process control, and devices are described. Topics investigated include: measurements of transistor delay time; application of the infrared response technique to the study of radiation-damaged, lithium-drifted silicon detectors; and identification of a condition that minimizes wire flexure and reduces the failure rate of wire bonds in transistors and integrated circuits under slow thermal cycling conditions. Supplementary data concerning staff, standards committee activities, technical services, and publications are included as appendixes.

Bullis, W. M.↗
NASA NTRS2010

Onboard Processing of Multispectral and Hyperspectral Data of Volcanic Activity for Future Earth-Orbiting and Planetary Missions

Autonomous onboard processing of data allows rapid response to detections of dynamic, changing processes. Software that can detect volcanic eruptions from thermal emission has been used to retask the Earth Observing 1 spacecraft to obtain additional data of the eruption. Rapid transmission of these data to the ground, and the automatic processing of the data to generated images, estimates of eruption parameters and maps of thermal structure, has allowed these products to be delivered rapidly to volcanologists to aid them in assessing eruption risk and hazard. Such applications will enhance science return from future Earth-orbiting spacecraft and also from spacecraft exploring the Solar System, or beyond, which hope to image dynamic processes. Especially in the latter case, long communication times between the spacecraft and Earth exclude a rapid response to what may be a transient process - only using onboard autonomy can the spacecraft react quickly to such an event.

Jupiter↗
NASA NTRSDate not supplied

Design and Assembly Process Implementation for Embedding Passive and Active Components Introduction to IPC-7092

"This presentation describes the design and assembly challenges for implementing passive and active components, in either formed or inserted methodology, into a printed board. The completed structure including internal electronic components is ready for surface mount and/or through-hole component attachment. The multilayered structure becomes a complete product ready for further processing in an assembly process and be made from organic, inorganic (ceramic) or both types of material."

embedded circuitry↗
DOE OSTI2026

Scaled melter testing of alternative reductants for Low-Activity Waste vitrification: Melter feed properties and processing behavior

This study examines the use of boron nitride (BN) and coke dust as alternative reductants for low-activity waste vitrification in scaled melter systems, intended to enhance operational flexibility at the Hanford Waste Treatment and Immobilization Plant. The baseline reductant, sucrose, while widely considered advantageous for glass production rates, produces challenging off gas emissions during processing. Early crucible-scale testing indicated that BN and coke effectively control foaming and glass redox, while significantly reducing acetonitrile emissions. Both real tank waste and simulant waste melter feeds were tested with BN and coke in this study. Rheological properties for melter feeds with both reductants were within operational limits, although the particle size of coke should be controlled and sufficient agitation is necessary to ensure smooth operations. While promising for handling and reduction of emissions, both simulant melter feeds demonstrated lower average glass production rates in the simulant melter system compared with sucrose. In the radioactive system, the rates were more comparable to previously measured low activity waste feeds on the order of 1285 kg m 2 day −1 for BN and 1671 kg m −2 day −1 for coke. Further scale-up testing is required to interpret the processing rates in the context of the full scale melter systems and evaluate the cost-benefit impact of these reductants on efficiency and sustainability.

Rigby, Jessica C. [Pacific Northwest National Labo↗
NASA NTRS1972

Methods of measurement for semiconductor materials, process control, and devices

Activities directed toward the development of methods of measurement for semiconductor materials, process control, and devices are described. Accomplishments include the determination of the reasons for differences in measurements of transistor delay time, identification of an energy level model for gold-doped silicon, and the finding of evidence that it does not appear to be necessary for an ultrasonic bonding tool to grip the wire and move it across the substrate metallization to make the bond. Work is continuing on measurement of resistivity of semiconductor crystals; study of gold-doped silicon; development of the infrared response technique; evaluation of wire bonds and die attachment; measurement of thermal properties of semiconductor devices, delay time, and related carrier transport properties in junction devices, and noise properties of microwave diodes; and characterization of silicon nuclear radiation detectors.

Bullis, W. M.↗
NASA NTRS1984

Wind tunnel simulations of aerolian processes

The characteristics of aerolian (wind) activity as a surface modifying process on Earth, Mars, Venus, and appropriate satellites was determined. A combination of spacecraft data analysis, wind tunnel simulations, and terrestrial field analog studies were used to determine these characteristics. Wind tunnel experiments simulating Venusian surface conditions demonstrate that rolling of particles may be an important mode of transport by winds on Venus and that aerolian processes in the dense atmosphere may share attributes of both aerolian and aqueous environments on Earth.

Greeley, R.↗
NASA NTRS1993

Studies of electromagnetic ion cyclotron waves using AMPTE/CCE and Dynamics Explorer

The principal activity during the past six months has involved the analysis of ion cyclotron waves recorded from DE-2 using the magnetic field experiment and electric field experiment. The results of this study have been published in the Geophysical Research Letters (GRL). The primary finding of this paper is that ion cyclotron waves were found to heat electrons, as observed in the DE-2 Langmuir probe data, through a Landau damping process. A second activity, which was started during the last six months, involves the study of large amplitude approximately one Hz electric and magnetic field oscillations recorded in the nightside auroral zone at substorm onset. Work is under way to determine the properties of these waves and investigate any association these waves may have with the substorm initiation process. A third activity under way involves a comprehensive study of ion cyclotron waves recorded at ionospheric altitudes by DE-2. This study will be an extension of the work reported in the GRL paper and will involve a larger sampling of wave events. This paper will focus on wave properties at ionospheric altitudes. A fourth activity involves a more in-depth analysis of the acceleration mechanisms and the resulting electron distributions based on the observations presented in the GRL paper.

Erlandson, Robert E.↗
NASA NTRS1998

Cloud and Radiation Mission with Active and Passive Sensing from the Space Station

A cloud and aerosol radiative forcing and physical process study involving active laser and radar profiling with a combination of passive radiometric sounders and imagers would use the space station as an observation platform. The objectives are to observe the full three dimensional cloud and aerosol structure and the associated physical parameters leading to a complete measurement of radiation forcing processes. The instruments would include specialized radar and lidar for cloud and aerosol profiling, visible, infrared and microwave imaging radiometers with comprehensive channels for cloud and aerosol observation and specialized sounders. The low altitude,. available power and servicing capability of the space station are significant advantages for the active sensors and multiple passive instruments.

Spinhirne, James D.↗
NASA NTRS2015

Benefits Assessment for Single-Airport Tactical Runway Configuration Management Tool (TRCM)

The System-Oriented Runway Management (SORM) concept was developed as part of the Airspace Systems Program (ASP) Concepts and Technology Development (CTD) Project, and is composed of two basic capabilities: Runway Configuration Management (RCM), and Combined Arrival/Departure Runway Scheduling (CADRS). RCM is the process of designating active runways, monitoring the active runway configuration for suitability given existing factors, and predicting future configuration changes; CADRS is the process of distributing arrivals and departures across active runways based on local airport and National Airspace System (NAS) goals. The central component in the SORM concept is a tool for taking into account all the various factors and producing a recommendation for what would be the optimal runway configuration, runway use strategy, and aircraft sequence, considering as many of the relevant factors required in making this type of decision, and user preferences, if feasible. Three separate tools were initially envisioned for this research area, corresponding to the time scale in which they would operate: Strategic RCM (SRCM), with a planning horizon on the order of several hours, Tactical RCM (TRCM), with a planning horizon on the order of 90 minutes, and CADRS, with a planning horizon on the order of 15-30 minutes[1]. Algorithm development was initiated in all three of these areas, but the most fully developed to date is the TRCM algorithm. Earlier studies took a high-level approach to benefits, estimating aggregate benefits across most of the major airports in the National Airspace Systems (NAS), for both RCM and CADRS [2]. Other studies estimated the benefit of RCM and CADRS using various methods of re-sequencing arrivals to reduce delays3,4, or better balancing of arrival fixes5,6. Additional studies looked at different methods for performing the optimization involved in selecting the best Runway Configuration Plan (RCP) to use7-10. Most of these previous studies were high-level or generic in nature (not focusing on specific airports), and benefits were aggregated for the entire NAS, with relatively low fidelity simulation of SORM functions and aircraft trajectories. For SORM research, a more detailed benefits assessment of RCM and CADRS for specific airports or metroplexes is needed.

Oseguera-Lohr, Rosa↗
NASA NTRS1987

Materials processing in space program support

Activities in support of NASA's Materials Processing in Space (MPS) program are reported. The overall task of the MPS project support contract was to provide the organization and administration of colloquiums, science reviews, workshops, technical meetings, bibliographic services, and visiting scientist programs. The research objectives and accomplishments of the University Space Research Association visiting scientist team are also summarized.

Glicksman, Martin↗
NASA NTRS1986

The materials processing research base of the Materials Processing Center

An annual report of the research activities of the Materials Processing Center of the Massachusetts Institute of Technology is given. Research on dielectrophoresis in the microgravity environment, phase separation kinetics in immiscible liquids, transport properties of droplet clusters in gravity-free fields, probes and monitors for the study of solidification of molten semiconductors, fluid mechanics and mass transfer in melt crystal growth, and heat flow control and segregation in directional solidification are discussed.

Latanision, R. M.↗
DOE OSTI2023

Activity coefficient acquisition with thermodynamics–informed active learning for phase diagram construction

This work explores the use of thermodynamics-informed Gaussian processes (GPs) and active learning (AL) to model activity coefficients and construct phase diagrams. Relying on synthetic data generated from an excess Gibbs energy model, GPs were found to accurately describe the activity coefficients of several binary mixtures across large composition and temperature ranges. Moreover, GPs could estimate their own uncertainty and identify composition/temperature regions where activity coefficient data provide the most information to the models. This was leveraged to build AL algorithms targeted at modeling phase equilibria. In many cases, a single active-learning-acquired data point was sufficient to describe the phase diagrams studied. Lastly, the ability of AL to greatly reduce the amount of data needed to obtain accurate models was further verified on experimental case studies, namely individual ion activity coefficients, the solid–liquid and vapor–liquid equilibrium of deep eutectic solvents, and phase equilibria in ternary mixtures.

25 ENERGY STORAGE↗
DOE OSTI2021

Technical Note CRYOFRABR#002/2021: Activated-copper-coated alumina granules synthesis

Detailed experimental studies of oxygen capture in the argon purification process using activated-copper on alumina and layered double hydroxide (LDH) were carried out, and the results were compared to the BASF commercial copper material Cu-0226 S performance. Here, we report the following main findings: i) the desired crystal structures for the studied materials were obtained after the synthesis process, ii) the use of the LDH structure promoted greater dispersion of the CuO phase when compared to BASF commercial catalyst, iii) alumina impregnated with copper demonstrated a similar result as the BASF sample for O 2 capture, and iv) among the three samples evaluated, the LHD sample demonstrated the best results regarding oxygen capturing performance becoming a promising structure for further studies.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Analytic Neural Network Gaussian Process Enabled Chance-Constrained Voltage Regulation for Active Distribution Systems with PVs, Batteries and EVs

This paper proposes an analytic neural network Gaussian process (NNGP)-based chance-constrained real-time voltage regulation method for active distribution systems with photovoltaics (PVs), batteries, and electric vehicles (EVs). NNGP can utilize historical measurement data to achieve real-time probabilistic node voltage estimation through Bayesian inference. Then, NNGP is fully analytically embedded into the optimal power flow model to perform voltage regulation and adapt to various topological changes. The uncertainties of voltage estimations are easily considered via the chance constraint, and it has been shown that the adoption of this chance constraint can significantly improve the reliability of voltage regulation under various scenarios. The comparison results with other methods, carried out on a real 759-node distribution system located in western Colorado, U.S., show that the proposed method can achieve accurate voltage estimation across different topologies and reliably perform voltage regulation considering PVs, batteries, and EVs.

active distribution systems↗
DOE OSTI2020

Predicting the propensity for thermally activated β events in metallic glasses via interpretable machine learning

Abstract The elementary excitations in metallic glasses (MGs), i.e., β processes that involve hopping between nearby sub-basins, underlie many unusual properties of the amorphous alloys. A high-efficacy prediction of the propensity for those activated processes from solely the atomic positions, however, has remained a daunting challenge. Recently, employing well-designed site environment descriptors and machine learning (ML), notable progress has been made in predicting the propensity for stress-activated β processes (i.e., shear transformations) from the static structure. However, the complex tensorial stress field and direction-dependent activation could induce non-trivial noises in the data, limiting the accuracy of the structure-property mapping learned. Here, we focus on the thermally activated elementary excitations and generate high-quality data in several Cu-Zr MGs, allowing quantitative mapping of the potential energy landscape. After fingerprinting the atomic environment with short- and medium-range interstice distribution, ML can identify the atoms with strong resistance or high compliance to thermal activation, at a high accuracy over ML models for stress-driven activation events. Interestingly, a quantitative “between-task” transferring test reveals that our learnt model can also generalize to predict the propensity of shear transformation. Our dataset is potentially useful for benchmarking future ML models on structure-property relationships in MGs.

36 MATERIALS SCIENCE↗
NASA NTRS1988

Pupil measures of alertness and mental load

A study of eight adults given active and passive search tasks showed that evoked pupillary response was sensitive to information processing demands. In particular, large pupillary diameter was observed in the active search condition where subjects were actively processing information relevant to task performance, as opposed to the passive search (control) condition where subjects passively viewed the displays. However, subjects may have simply been more aroused in the active search task. Of greater importance was that larger pupillary diameter, corresponding to longer search time, was observed for noncoded than for color-coded displays in active search. In the control condition, pupil diameter was larger with the color displays. The data indicate potential usefulness of pupillary responses in evaluating the information processing requirements of visual displays.

Backs, Richard W.↗
NASA NTRS1974

Status of NASA space-processing research

A survey is presented of the history, goals, objectives, and implementation of the NASA space processing program. Program activities have resulted in the present division of interests into metallurgical processes, electronic materials, biological applications, ceramics and glass, physical properties in fluids, and chemical processes. An outline is given of space shuttle payload development.

Bredt, J. H.↗