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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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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

A component decomposition model for evaluating atmospheric effects in remote sensing

A radiance value of a target pixel recorded by a remote sensor can be decomposed into three components: (1) attenuated target signature, (2) pure atmospheric radiation, and (3) the contribution made by the ground through the atmospheric scattering process. Given the meteorological and optical parameters of a layer-structured atmosphere, its transmittance and radiance distribution can be accurately calculated with a plane-parallel radiative transfer model. For a uniform surface, the ground contribution can be obtained by comparing radiances for an atmosphere over a black but nonemitting surface and the same atmosphere with an underlying ground of given albedo or temperature. For an inhomogeneous surface, the first two components remain the same as long as the surface is a plane. The third may be estimated using the locally averaged top-of-atmosphere radiance. An atmospheric point spread function is calculated by a Monte Carlo approach and is used for retrieving the ground signature through a deconvolution procedure.

Li, S.↗
DOE OSTI2014

Synergistic inhibition of cancer cell proliferation with a combination of δ-tocotrienol and ferulic acid

Highlights: • δ-Tocotrienol (δ-T3) and ferulic acid (FA) synergistically inhibit cancer cell growth. • The combination of δ-T3 and FA induces G1 arrest by up-regulating p21. • The synergy is attributed to an increase in the cellular concentration of δ-T3 by FA. - Abstract: Rice bran consists of many functional compounds and thus much attention has been focused on the health benefits of its components. Here, we investigated the synergistic inhibitory effects of its components, particularly δ-tocotrienol (δ-T3) and ferulic acid (FA), against the proliferation of an array of cancer cells, including DU-145 (prostate cancer), MCF-7 (breast cancer), and PANC-1 (pancreatic cancer) cells. The combination of δ-T3 and FA markedly reduced cell proliferation relative to δ-T3 alone, and FA had no effect when used alone. Although δ-T3 induced G1 arrest by up-regulating p21 in PANC-1 cells, more cells accumulated in G1 phase with the combination of δ-T3 and FA. This synergistic effect was attributed to an increase in the cellular concentration of δ-T3 by FA. Our results suggest that the combination of δ-T3 and FA may present a new strategy for cancer prevention and therapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water

In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO{sub 2} nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles. - Highlights: • Develop effective photocatalyst based on PAN–CNT/TiO{sub 2}–NH{sub 2} composite nanofibers. • High photodegradation efficiency and fast kinetics was obtained. • Regeneration of the composite nanofibers allowed the reuse of these material. • Mechanism of the photocatalytic degradation was proposed. • The flexibility of the composite nanofibers allows use in a continuous operation mode.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Landau damping in a multi-component dusty plasma

Effect of the dust size distribution on the landau damping and the wave frequency is studied in the present paper. It is found that wave frequency increases as either the difference between the largest and the smallest dust size increases or the wave number increases. It seems that wave frequency is smaller for dusty plasma whose density of the smaller grains is larger than that of the larger ones, while it is larger in the opposite case. The effect of the dust size distribution can increase the Landau damping in the cases where the temperature of the dust grains is small enough or high enough.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Simulation of the NuScale SMR and Investigation of the Effect of Load-Following on Component Lifetimes

The NuScale SMR has been modelled using the Virtual Environment for Reactor Applications (VERA) multiphysics environment and the results compared with the publicly reported data in the Design Certification Application (DCA). The results show an excellent agreement for the compared axial and radial power distributions, temperature coefficients of reactivity, boron and control rod worths, and fast neutron flux. This NuScale model is then used to investigate the effect of different operational modes on reactor components to determine how flexible load-following operation may affect control rod and reactor pressure vessel (RPV) lifetimes. The control rod degradation is confirmed to primarily affect the silver-indium-cadmium (AIC) rod tip. The degradation rate is observed to follow a non-linear function of core power level where the increase in degradation decreases with insertion depth. For the variation in core power levels expected with current load-following schemes, the total control rod degradation is found to be mild, at 5-10% of usable life per cycle for a reactor operating at <80% power. Nonetheless, this enables load following strategies to be confirmed and/or modified to ensure that control rods do not need to be replaced during the 60+ year life of the reactor. The RPV degradation was found to be almost directly proportional to the core power level and was not overly sensitive to flux shape perturbations. Future work is planned using these damage functions to optimize operation over multiple NuScale SMR units and develop strategies for prognostics and health management.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS2017

The Effect of Shock on the Amorphous Component in Altered Basalt

Investigation of the geochemical and mineralogical composition of the Martian surface provides insight into the geologic history of the predominantly basaltic crust. The Chemistry and Mineralogy (CheMin) instrument onboard the Curiosity rover has returned the first X-Ray diffraction data from the Martian surface. However, large proportions (27 +/- 14 with some estimates as high as 50 weight percentage) of an amorphous component have been reported. As a remedy to this problem, mass balance equations using geochemistry, volatile chemistry, and mineralogy have been employed to constrain the geochemistry of the amorphous component. However, "the nature and number of amorphous phases that constitute the amorphous component is not unequivocally known". Multiple hypotheses have been proposed to explain the origin of this amorphous component: Allophane (Al2O); Basaltic glass (Volcanic and impact); Palagonite (Altered basaltic glass); Hisingerite (Fe (sup 3 plus)-bearing phyllosilicate); S/Cl-rich component (sulfates and/or akaganeite); Nanophase ferric oxide component (npOx). Establishing a multi-phase amorphous component from a basaltic precursor that has undergone physical and chemical weathering within geochemical constraints is of paramount importance to better understand the composition of a large portion of the Martian surface (up to 50 weight percentage). Shocked basalts from Lonar Crater in India are valuable analogs for the Martian surface because it is a well-preserved impact crater in a basaltic target. Having undergone pre- and post-shock aqueous alteration, these rocks provide crucial data regarding the effect of shock on the amorphous component in altered basalt. By conducting mass balance equations similar to what has been performed for Gale crater materials, we attempt to calculate the geochemistry of the amorphous component in altered basalts ranging from unshocked to Class 5 (Table 1). This has the potential to reveal the nature and origin (i.e. primary igneous, shock metamorphic, and/or aqueous alteration occurring before or after the impact event) of the amorphous component in shocked basalt with the goal of unravelling the history of the Martian surface.

Eckley, S. A.↗
DOE OSTI2025

Assessing the Long-Term Stability of Anion Exchange Membranes for Electrochemical CO 2 Reduction

Materials and cell components used in CO 2 electrolysis have largely been adapted from technologies initially developed for water electrolysis and fuel cells. However, electrochemical CO 2 reduction introduces distinct material challenges due to the unique chemical environment in this process. Here, in this study, we conducted ex-situ 1000 h stability tests on commonly used anion exchange membranes, exposing them exclusively to electrolytes and organic molecules used or produced during CO 2 electrolysis, at concentrations relevant to and compatible with postseparation processes. Notably, 15% w/w n-propanol and 5 M acetic acid caused complete dissolution or partial disintegration of the membranes unless cross-linking was present and remained stable throughout the test. When the membranes stayed physically intact, most of them exhibited excellent chemical stability in alkaline medium containing alcohols or formic acid, which was confirmed by vibrational spectroscopy and ion exchange capacity measurements. However, exposure to alcohol-and acid-containing solutions led to a substantial increase in swelling and water uptake, with potential implications for mechanical stability, ion/product crossover, and compression management of adjacent components. The potential effects of CO 2 electroreduction products on membrane stability, their subsequent impact on electrolyzer performance, and mitigation strategies are discussed.

CO2RR↗
NASA NTRS1993

Correlation of ground tests and analyses of a dynamically scaled Space Station model configuration

Verification of analytical models through correlation with ground test results of a complex space truss structure is demonstrated. A multi-component, dynamically scaled space station model configuration is the focus structure for this work. Previously established test/analysis correlation procedures are used to develop improved component analytical models. Integrated system analytical models, consisting of updated component analytical models, are compared with modal test results to establish the accuracy of system-level dynamic predictions. Design sensitivity model updating methods are shown to be effective for providing improved component analytical models. Also, the effects of component model accuracy and interface modeling fidelity on the accuracy of integrated model predictions is examined.

Javeed, Mehzad↗
NASA NTRS1993

Correlation of ground tests and analyses of a dynamically scaled space station model configuration

Verification of analytical models through correlation with ground test results of a complex space truss structure is demonstrated. A multi-component, dynamically scaled space station model configuration is the focus structure for this work. Previously established test/analysis correlation procedures are used to develop improved component analytical models. Integrated system analytical models, consisting of updated component analytical models, are compared with modal test results to establish the accuracy of system-level dynamic predictions. Design sensitivity model updating methods are shown to be effective for providing improved component analytical models. Also, the effects of component model accuracy and interface modeling fidelity on the accuracy of integrated model predictions is examined.

Javeed, Mehzad↗
NASA NTRS2019

Compositional and Microstructural Effects in the Protection of SiC Components in Water Vapor

Greater gas turbine engine efficiency is a major goal in aeronautics research often pursued through increased engine operating temperatures. However, it is necessary to replace the current hot-stage alloy components with more thermally robust parts, such as promising Silicon-based ceramics and composites. Unfortunately, these materials are still susceptible to the effects of oxidation, water vapor, and (Calcium-Magnesium-Alumino-Silicate) CMAS interaction, among other issues at high temperature. To mitigate these effects, environmental barrier coating (EBC) materials are employed to help control the rate of degradation to the underlying composite. Often, a thermally grown oxide (TGO) layer forms between the EBC and the composite which can act as a point of failure. The current study focuses on the combined effects of water vapor, composite composition, and microstructure in TGO formation on protected and unprotected SiC samples which have been produced under different processing conditions.

Kowalski, Benjamin↗
DOE OSTI2019

Effects of Prostatic Artery Embolization on the Dynamic Component of Benign Prostate Hyperplasia as Assessed by Ultrasound Elastography: A Pilot Series

Purpose: To determine the effects of prostatic artery embolization (PAE) on prostatic elasticity as assessed by Ultrasound Elastography (US-E), as well as to describe the feasibility and role of US-E as a novel tool in both pre- and post-PAE evaluation. Materials and Methods: This is a prospective, single-center investigation that included eight patients undergoing PAE for treatment of lower urinary tract symptoms (LUTS) attributed to benign prostate hyperplasia (BPH). Baseline and 3-month follow-up evaluations were performed and included prostate-specific antigen (PSA), uroflowmetry, pelvic magnetic resonance imaging and clinical assessment using the International Prostate Symptom Score (IPSS) questionnaire and the IPSS-Quality of life (QoL) item. US-E with measurement of the prostatic Elastic Modulus (EM) was performed before PAE and at 1-month follow-up. Results: After PAE, US-E showed a significant reduction of prostatic EM as assessed in kPa (33.14 vs. 47.24, − 29.8%, p = 0.002) and in m/s (3.75 vs. 4.63, − 19.0%, p < 0.001). Also, the transitional/peripheral zone ratio was significantly reduced by 45.36% (0.53 vs. 0.97, p < 0.05). All eight patients presented with significant LUTS improvement after PAE (p < 0.05 for IPSS, QoL, prostate volume, peak urinary flow rate and PSA). Conclusions: Findings described in this study suggest that PAE significantly reduces prostatic EM, leading to a positive effect on BPH dynamic component related to prostatic elasticity. Also, it features US-E as an additional tool for pre- and post-PAE evaluation, describing a novel indication for this technology.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

The low-energy N = 4 SYM effective action in diverse harmonic superspaces

We review various superspace approaches to the description of the low-energy effective action in N = 4 super Yang-Mills (SYM) theory. We consider the four-derivative part of the low-energy effective action in the Coulomb branch. The typical components of this effective action are the gauge field F{sup 4}/X{sup 4} and the scalar field Wess-Zumino terms. We construct N = 4 supersymmetric completions of these terms in the framework of different harmonic superspaces supporting N = 2,3,4 supersymmetries. These approaches are complementary to each other in the sense that they make manifest different subgroups of the total SU(4) R-symmetry group. We show that the effective action acquires an extremely simple form in those superspaces which manifest the non-anomalous maximal subgroups of SU(4). The common characteristic feature of our construction is that we restore the superfield effective actions exclusively by employing the N = 4 supersymmetry and/or superconformal PSU(2, 2| 4) symmetry.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1992

Shortcomings in ground testing, environment simulations, and performance predictions for space applications

This paper addresses the issues involved in radiation testing of devices and subsystems to obtain the data that are required to predict the performance and survivability of satellite systems for extended missions in space. The problems associated with space environmental simulations, or the lack thereof, in experiments intended to produce information to describe the degradation and behavior of parts and systems are discussed. Several types of radiation effects in semiconductor components are presented, as for example: ionization dose effects, heavy ion and proton induced Single Event Upsets (SEUs), and Single Event Transient Upsets (SETUs). Examples and illustrations of data relating to these ground testing issues are provided. The primary objective of this presentation is to alert the reader to the shortcomings, pitfalls, variabilities, and uncertainties in acquiring information to logically design electronic subsystems for use in satellites or space stations with long mission lifetimes, and to point out the weaknesses and deficiencies in the methods and procedures by which that information is obtained.

Stassinopoulos, E. G.↗
NASA NTRS1998

Protocol Development for the NASA-JSC Lunar-Mars Life Support Test Project (LMLSTP) Phase 3 Project: A Report on Baseline Studies at KSC for Continuous Salad Production

The Phase 3 Lunar-Mars Life Support Test Project (LMLSTP) was conducted in a 20-foot chamber at Johnson Space Center. The overall objective of the Phase 3 project was to conduct a 90-day regenerative life support system test involving 4 human subjects to demonstrate an integrated biological and physicochemical life support system. A secondary objective of the Phase 3 LMLSTP was to demonstrate the ability to produce salad-type vegetable by integration of a small benchtop growth chamber located within the crew habitat area. This small chamber, commercially manufactured as the Controlled Environment Research Ecosystem (CERES 2010(TM)), functioned as a means to continuously provide fresh lettuce crops for crew members. The CERES 2010(TM) growth chamber utilized hardware components developed for effective plant biomass production in spaceflight applications. These components included: (1) LED lighting; (2) Astroculture(TM) Root Trays; and (3) Zeoponic media. In planning for the LMLSTP Phase 3, a request was put forward for KSC scientists to generate a protocol for successful continuous planting, culturing, and harvesting of the salad-crop, lettuce. By conducting baseline tests with components of the CERES 2010(TM), a protocol was developed.

Goins, G. D.↗
DOE OSTI2019

Systematic Structure and Sinks in the YORP Effect

There is a correlation between the components of the YORP effect of most asteroids, which drives the obliquity and spin rate of the affected bodies in a consistent pattern. This allows for a clear and unambiguous picture for how the spin rates and poles of asteroids affected by YORP will evolve and simplifies the overall picture for how populations will migrate on average. The YORP effect can also lead to a previously unexplored equilibrium state for affected bodies. This equilibrium state is a function of the usual normal YORP effect (which arises due to the global shape asymmetry of the asteroid) and the tangential YORP effect (which arises due the transport of thermal energy through rocky surface features). Estimates from current shape models show that 10%–20% of asteroids have the proper condition to be captured in this equilibrium state, indicating that the occurrence of this state may be significant. The existence of this attractor for the asteroid population means that objects affected by YORP may leave their usual YORP cycles and maintain a constant spin rate over long time periods—this has significant implications for our interpretation of asteroid spin rate evolution and related theories for their physical evolution.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Distinct non-invasive evaluation values of tumor-derived cell-free microRNAs, circulating microvesicles and exosomal microRNAs after renal carcinoma cryoablation

Highlights: • Circulating components could be used for the non-invasive evaluation of renal tumor cryoablation therapeutic effects. • Different circulating components have distinct roles in the evaluation of renal tumor cryoablation. • Exosomal microRNAs may be more suitable for the early postoperative judgment of tumor elimination effects. The detection of peripheral circulating tumor-derived components, such as cell-free microRNAs, circulating microvesicles, and exosomal microRNAs, has been shown as a promising noninvasive strategy. However, the different roles of these components in tumor therapy evaluations have remained largely undefined. In this paper, we employed an in vivo model of the human clear cell renal cell carcinoma line Caki-1-bearing mice to evaluate the therapeutic effects of cryoablation, which is a new minimally invasive treatment for renal cell carcinoma. At different times after cryoablation, we found that the levels of the cell-free microRNAs miR-122, miR-155 and miR-210 were first increased and then decreased. Additionally, the number of large-sized microvesicles was increased after cryoablation, but the number of small-sized circulating microvesicles did not change. Furthermore, the exosomal microRNAs miR-126–3p, miR-17–5p, and miR-21–3p rapidly decreased one day after cryoablation, an effect that was well correlated with the treatment degree. Therefore, we suggest that these circulating components may have different levels of importance in the evaluation of the efficacy of renal cell cryoablation, furthermore, exosomal microRNAs may be more suitable for the early postoperative judgment of tumor elimination effects, which are worth further exploration in clinical practice.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Temperature and Composition Dependence Modeling of Viscosity and Electrical Conductivity of Low-Activity Waste Glass Melts

The development of models that accurately relate the properties of a glass melt to its temperature and composition is important for glass formulation, melter control, and modeling the melt flow, refractory corrosion, and production rate. Using a database consisting of more than 4,000 data points measured between 900 °C and 1250 °C for over 600 unique low-activity waste glass compositions, we developed models for the melt viscosity and electrical conductivity. Models based on the Gaussian process regression approach outperformed models based on the Vogel–Fulcher–Tammann equation according to four standard metrics and yielded reliable prediction intervals. The models found primarily linear effects between properties and individual components, except for the effect of the Na 2 O mass fraction on the electrical conductivity. The effects were found to be consistent with current theories on physical processes involved with those properties.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Dispenser Reliability: Materials R&D. A Hydrogen Fueling Infrastructure Research and Station Technology (H2FIRST) Report

Dispensers are the top cause of maintenance events and down-time at hydrogen fueling stations. In an effort to help characterize and enable improvements in dispenser reliability, an extensive accelerated lifetime testing set-up was designed and built at NREL involving components typically part of dispensing operations at fueling stations. Device Under Test (DUTs) included different components such as normally open valves, normally closed valves, fueling nozzles, breakaways devices and filters. Conditions of testing included pressures, and flow rates similar to light duty fuel cell electric vehicles fueling at -40°C, and -20°C for thousands of cycles in hydrogen. Tested components (failed and non-failed) were disassembled at SNL and polymeric O-rings were carefully retrieved and cataloged for chemical and physical characterization. Data collected was compared to similar O-rings from unexposed or non-tested components for hydrogen effects, and failure modes. Degradation analyses, based on select polymer chemistries common across all component types, their location within components, visual assessment of damage coupled with strong hydrogen effects from chemical characterization, was completed and presented to NREL and DOE. Overall, the failure rate amongst the components was not as high as expected for the test conditions. Among the component types tested, breakaways were the most susceptible to damage under these test conditions, with fueling nozzles a close second. The proper combination of selection of the right polymer and optimum component design was found to make a strong difference in component reliability under severe dispenser operating conditions. Physical degradation of polymers, rather than chemical changes due to low temperature hydrogen exposure, is more prevalent as failure mode for these test conditions. The nature and the extent of the degradation was much less at -20°C as compared to -40°C. The damage and failure rates were higher at lower temperatures than at higher test temperatures. As expected, increasing the number of cycles at the lowest test temperature (-40°C) increased damage. This indicates that cycling at the low temperature of -40°C required by SAE J2601 can reduce component life in fuel dispensing operations

08 HYDROGEN↗