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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 1,207 records · Page 67
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

International Space Station Urine Monitoring System Functional Integration and Science Testing

Exposure to microgravity during human spaceflight needs to be better understood as the human exploration of space requires longer duration missions. It is known that long term exposure to microgravity causes bone loss. Measuring the calcium and other metabolic byproducts in a crew member s urine can evaluate the effectiveness of bone loss countermeasures. The International Space Station (ISS) Urine Monitoring System (UMS) is an automated urine collection device designed to collect urine, separate the urine and air, measure the void volume, and allow for syringe sampling. Accurate measuring and minimal cross-contamination is essential to determine bone loss and the effectiveness of countermeasures. The ISS UMS provides minimal cross-contamination (<0.7 mL urine) and has volume accuracy of 2% between 100 to 1000 mL urine voids. Designed to provide a non-invasive means to collect urine samples from crew members, the ISS UMS operates in-line with the Node 3 Waste and Hygiene Compartment (WHC). The ISS UMS has undergone modifications required to interface with the WHC, including material changes, science algorithm improvements, and software platform revisions. Integrated functional testing was performed to determine the pressure drop, air flow rate, and the maximum amount of fluid capable of being discharged from the UMS to the WHC. This paper will detail the results of the science and the functional integration tests.

Rodriquez, Branelle R.↗
NASA NTRS2019

Transitioning the NASA SLR Network to Event Timing Mode for Reduced Systematics, Improved Stability and Data Precision

NASA's legacy Satellite Laser Ranging (SLR) network produces about one-third of the global SLR data to support spacegeodesy. This network of globally distributed stations has been using Time Interval Units (TIU) for range measurements for thelast 25 + years. To improve the reliability of the SLR network and satisfy the need for stable millimeter precision data, a phasedreplacement of the TIUs in the network with picosecond-precise Event Timer Modules was initiated in 2015. This schemeallowed the time of flight and laser transmit epoch measurement to one picosecond resolution. For a network with globalscientific impact, transitioning to a new data generation metrological scheme requires significant data scrutiny and long-termscience data validation. Any long-term testing/measurement has the potential to interrupt the station's daily operational dataflow to the International Laser Ranging Service (ILRS) as the station under test will have to put its test data into quarantine.We have demonstrated a very effective way to test and implement the new device without removing the old hardware andwithout the need for the orbit analysis. This operationally noninvasive scheme performed concurrent test measurements enablinguninterrupted operational data flow to the users, while allowing simultaneous test data capture for short- and long-termsystematics and stability analysis. Extensive analysis of the test data was performed by the NASA SLR engineering team andthe ILRS Analysis Standing Committee, to uncover biases and any dependencies on the satellite ranges (for nonlinear scaleissues). Multi-ETM comparison was also performed at two of the SLR stations through the interchange of hardware to establishthe inter-device range biases and stability. Such benchmarked hardware was subsequently sent to the remaining stationsto allow traceability and normalize the network performance. The range bias intercomparison performed using the multiyearSLR data analysis agreed well with the engineering changes, thus validating the approach to flush out station-specific rangingsystematics affecting precise orbit determination. Such an improvement and rebalancing of the current network will allowan orderly transition of the current NASA SLR network operating at a maximum rate of 10 Hz to the NASA next generationSpace Geodesy Satellite Laser Ranging (SGSLR) network operating at 2 kHz (McGarry et al. in J Geod, 2018. https ://doi.org/10.1007/s0019 0-018-1191-6; Merkowitz et al. in J Geod, 2018. https ://doi.org/10.1007/s0019 0-018-1204-5).

Varghese, Thomas↗
NASA NTRS2019

The X-Ray Halo Scaling Relations of Supermassive Black Holes

We carry out a comprehensive Bayesian correlation analysis between hot halos and direct masses of supermassive black holes (SMBHs), by retrieving the X-ray plasma properties (temperature, luminosity, density, pressure, and masses) over galactic to cluster scales for 85 diverse systems. We find new key scalings, with the tightest relation being −, followed by −. The tighter scatter (down to 0.2 dex) and stronger correlation coefficient of all the X-ray halo scalings compared with the optical counterparts (as the −) suggest that plasma halos play a more central role than stars in tracing and growing SMBHs (especially those that are ultramassive). Moreover, correlates better with the gas mass than dark matter mass. We show the important role of the environment, morphology, and relic galaxies/coronae, as well as the main departures from virialization/self-similarity via the optical/X-ray fundamental planes. We test the three major channels for SMBH growth: hot/Bondi-like models have inconsistent anticorrelation with X-ray halos and too low feeding; cosmological simulations find SMBH mergers as subdominant over most of cosmic time and too rare to induce a central-limit-theorem effect; the scalings are consistent with chaotic cold accretion, the rain of matter condensing out of the turbulent X-ray halos that sustains a long-term self-regulated feedback loop. The new correlations are major observational constraints for models of SMBH feeding/feedback in galaxies, groups, and clusters (e.g., to test cosmological hydrodynamical simulations), and enable the study of SMBHs not only through X-rays, but also via the Sunyaev–Zel'dovich effect (Compton parameter), lensing (total masses), and cosmology (gas fractions).

Supermassive black holes↗
NASA NTRS1997

Oxygen Compatibility Screening Tests in Oxygen-Rich Combustion Environment

The identification and characterization of oxygen-rich compatible materials enables full-flow, staged combustion designs. Although these oxygen-rich designs offer significant cost, performance, and reliability benefits over existing systems, they have never been used operationally by the United States. If these systems are to be realized, it is critical to understand the long-term oxidative stability in high-temperature, high-pressure, oxygen-rich combustion environments. A unique facility has been constructed at the NASA Lewis Research Center to conduct tests of small-scale rocket engine materials and subcomponents in an oxygen-rich combustion environment that closely approximates a full-scale rocket engine. Thus, a broad range of advanced materials and concepts can be screened in a timely manner and at a relatively low cost.

Eckel, Anerew J.↗
NASA NTRS1987

Vestibulo-ocular and vestibulospinal function before and after cochlear implant surgery

Vestibular function in cochlear implant candidates varies from normal to total absence of function. In patients with intact vestibular function preoperatively, invasion of the otic capsule places residual vestibular function at risk. Speech-processing strategies that result in large amplitude electrical transients or strategies that employ high amplitude broad frequency carrier signals have the potential for disrupting vestibular function. Five patients were tested with and without electrical stimulation via cochlear electrodes. Two patients experienced subjective vestibular effects that were quickly resolved. No long-term vestibular effects were noted for the two types of second generation cochlear implants evaluated. Histopathological findings from another patient, who had electrically generated vestibular reflex responses to intramodiolar electrodes, indicated that responses elicited were a function of several variables including electrode location, stimulus intensity, stimulus amplitude, and stimulus frequency. Differential auditory, vestibulocolic, and vestibulospinal reflexes were demonstrated from the same electrode as a function of stimulus amplitude, frequency, and duration.

Case Reports↗
DOE OSTI2026

Evaluating the efficiency of touch-spun scaffolds in producing dense cell cultures for tissue engineering applications

Developing efficient scaffolds for long-term cell cultivation remains a challenge in tissue engineering. Biomimetic approaches aim to create a three-dimensional (3D) extracellular matrix (ECM)-like fiber network with a tunable hierarchical structure to promote sufficient cell attachment, differentiation, and overall viability. Among the fiber fabrication methods documented in the literature, mechanical fiber drawing techniques, such as touch-spinning, have garnered significant research interest. This is due to the simplicity of the equipment, the ability to control fiber diameter and interfiber spacing at the nanoscale without the need for external fields, and the absence of specific requirements for material dielectric properties. Despite the advantages of mechanically drawn scaffolds in biomedical research, the methodologies for cell culturing and analysis for these materials have not been adequately addressed. In this study, we assess the potential of touch-spun scaffolds in promoting NIH/3T3-GFP fibroblast cell growth for tissue engineering applications. Polycaprolactone/polyethylene oxide (PCL/PEO)-based fiber arrays with a controlled interfiber spacing of 91.9 ± 25.0 μm (N = 50) were fabricated using a modified touch-spinning apparatus and then assembled into 2D and 3D scaffolds through additive manufacturing technology. A comparative cell analysis conducted for single- and multi-layered structures showed that the 3D touch-spun scaffolds support healthy growth of up to 6.5 million fibroblast cells within 21 days and offer enhanced cell viability compared to conventional 2D fiber scaffolds, as confirmed by the Presto Blue assay. Furthermore, the metabolic activity of fibroblasts on 3D scaffolds assessed by the MTT test is approximately four times higher than that of the positive control, making the 3D touch-spun materials ideal for long-term cell culture applications.

Peranidze, Kristina [University of Georgia, Athens↗
NASA NTRS1984

Long-time dynamic compatibility of two ethylene propylene elastomers with hydrazine

A test method is described for predicting the long-time survivability of elastomers in hydrazine under dynamic stressing conditions. The method selected is based upon the existence and approximate invariance of a 'physical property surface' relating the mechanical response of the elastomer in terms of stress, strain, time, and temperature. The property surface was generated for two selected elastomers (EPT-10 and AF-E-332). A novel carousel testing tank was designed to allow sequential testing of eight tensile specimens immersed in liquid hydrazine within a constant-temperature water bath. The test procedure and data reduction methods used to generate the property surface are described. The utility and validity of these results applied to fatigue and flexure loading to these elastomeric materials over long-time periods are discussed.

Coulbert, C. D.↗
DOE OSTI2026

Enhancing Oxygen Evolution Reaction and Stability in Proton-Conducting Solid Oxide Electrolysis Cells (p-SOECs) via a Porous Gadolinium-Doped Ceria Interlayer

Proton-conducting solid oxide electrolysis cells (p-SOECs) offer a promising pathway for intermediate temperature (400-600 °C) hydrogen production. However, they still face critical challenges related to sluggish oxygen evolution reaction (OER) kinetics and low Faradaic efficiencies. Here, in this work, we demonstrate that introducing a thin (~0.8 µm) porous Gd 0.1 Ce 0.9 O 1.95 (GDC) interlayer between a BaCo 0.8 Zr 0.1 Zn 0.1 O 3-δ (BCZZ) oxygen electrode and electrolyte significantly enhances p-SOEC performance. The GDC interlayer reduces polarization resistance by 48% (0.54 to 0.28 O cm 2 ) and increases Faradaic efficiency from 63% to 81% at -0.8 A/cm 2 and 600 °C. GDC interlayer p-SOECs display elevated effective H 2 current densities compared to control p-SOECs and reach up to -1.22 A/cm 2 at 1.3 V. Mechanistic studies on the interactions between GDC and BCZZ reveal that GDC intrinsically promotes OER kinetics by significantly reducing the polarization activation energy (Ea p ), dropping from 1.45 to 1.22 eV for full p-SOECs and 0.98 to 0.76 eV for symmetric cells. This promotional effect is localized in the electrochemically active region near the electrolyte interface. Durability testing for over 1500 hours under 50% H 2 O conditions indicates that the GDC interlayer also improves long-term stability, with a degradation rate 53% lower than control p-SOECs. By pinpointing the interfacial region where GDC exerts its promotional effect, highlighting its role in enhancing OER kinetics, and establishing interlayer engineering as a powerful technique, this work provides a unified pathway to simultaneously improve p-SOEC activity, Faradaic efficiency, and durability.

08 - HYDROGEN↗
DOE OSTI2020

Acclimation of leaf respiration consistent with optimal photosynthetic capacity

Abstract Plant respiration is an important contributor to the proposed positive global carbon‐cycle feedback to climate change. However, as a major component, leaf mitochondrial (‘dark’) respiration ( R d ) differs among species adapted to contrasting environments and is known to acclimate to sustained changes in temperature. No accepted theory explains these phenomena or predicts its magnitude. Here we propose that the acclimation of R d follows an optimal behaviour related to the need to maintain long‐term average photosynthetic capacity ( V cmax ) so that available environmental resources can be most efficiently used for photosynthesis. To test this hypothesis, we extend photosynthetic co‐ordination theory to predict the acclimation of R d to growth temperature via a link to V cmax , and compare predictions to a global set of measurements from 112 sites spanning all terrestrial biomes. This extended co‐ordination theory predicts that field‐measured R d and V cmax accessed at growth temperature ( R d,tg and V cmax,tg ) should increase by 3.7% and 5.5% per degree increase in growth temperature. These acclimated responses to growth temperature are less steep than the corresponding instantaneous responses, which increase 8.1% and 9.9% per degree of measurement temperature for R d and V cmax respectively. Data‐fitted responses proof indistinguishable from the values predicted by our theory, and smaller than the instantaneous responses. Theory and data are also shown to agree that the basal rates of both R d and V cmax assessed at 25°C ( R d,25 and V cmax,25 ) decline by ~4.4% per degree increase in growth temperature. These results provide a parsimonious general theory for R d acclimation to temperature that is simpler—and potentially more reliable—than the plant functional type‐based leaf respiration schemes currently employed in most ecosystem and land‐surface models.

Wang, Han↗
DOE OSTI2020

Microbial potentiometric sensor technology for real-time detecting and monitoring of toxic metals in aquatic matrices

Considering that toxic metals can affect metabolic processes in microorganisms adversely, it can be hypothesized that these metals in water matrices would induce a decrease in metabolic activity of the biofilm microorganisms populating the surface of a sensing electrode, which could be registered as a change in the open-circuit potential (OCP) generated by the biofilm microorganisms. The goal of this study was to test this hypothesis and demonstrate the underlying principle that microbial potentiometric sensor (MPS) technology could be used for long-term and real-time monitoring and detection of rapid changes in metal concentrations in realistic aquatic environments. To address the goal, four objective were addressed: (1) a batch reactor with three graphite-based MPS electrodes was fabricated; (2) a set of single-ion solutions and one multiple ion solution were prepared reflecting realistic concentrations of metals found in electroplating wastewaters; (3) the responses of the MPS to the simultaneous presence of multiple toxic metal ions in a single solution were measured; and (4) the changes of the MPS signals to the presence of individual metal ion solutions were examined. While the hypothesis was validated, the study also revealed that the MPS was sufficiently sensitive to not only detect, but also quantify, toxic metal ion concentrations in aqueous solutions. The coefficients of determination, which were R 2 > 0.995, and responsiveness of <1 μmol/L for some toxic metal cations, strongly support the performance of MPS technology in the echelons of expensive analytical tools capable detecting and measuring trace elements.The magnitude of the MPS response was toxic metal specific. When the molar concertation normalizes the inhibition portion of the signal area, the assessed sensitivity order was: Se>Cd>Pb>Ag>Ni> Zn. The study provides valuable information for enforcement agents, environmental professionals, and wastewater treatment operators, so toxic metal pollution and its detrimental impacts can be prevented and mitigated.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

PV Module Operating Temperature - Data and Resources

The Photovoltaic Systems Evaluation Laboratory (PSEL) at Sandia National Laboratories (SNL) in Albuquerque, NM has an extensive test site where PV modules and other system components are deployed and monitored for testing and evaluation. For this dataset PV Performance Labs has assembled one year of measurements from the Systems Long-Term Evaluation (SLTE) project (formerly known as PV Lifetime) providing the main variables needed to investigate and validate PV module operating temperature models: irradiance, ambient temperature, wind speed and back-of-module temperature. For use with more advanced thermal modeling, an estimate of down-welling long-wave radiation is also included.

14 SOLAR ENERGY↗
DOE OSTI2024

Development of a plant carbon–nitrogen interface coupling framework in a coupled biophysical-ecosystem–biogeochemical model (SSiB5/TRIFFID/DayCent-SOM v1.0)

Plant and microbial nitrogen (N) dynamics and N availability regulate the photosynthetic capacity and capture, allocation, and turnover of carbon (C) in terrestrial ecosystems. Studies have shown that a wide divergence in representations of N dynamics in land surface models leads to large uncertainties in the biogeochemical cycle of terrestrial ecosystems and then in climate simulations as well as the projections of future trajectories. In this study, a plant C–N interface coupling framework is developed and implemented in a coupled biophysical-ecosystem–biogeochemical model (SSiB5/TRIFFID/DayCent-SOM v1.0). The main concept and structure of this plant C–N framework and its coupling strategy are presented in this study. This framework takes more plant N-related processes into account. The dynamic ratio (CNR) for each plant functional type (PFT) is introduced to consider plant resistance and adaptation to N availability to better evaluate the plant response to N limitation. Furthermore, when available N is less than plant N demand, plant growth is restricted by a lower maximum carboxylation capacity of RuBisCO (V c,max ), reducing gross primary productivity (GPP). In addition, a module for plant respiration rates is introduced by adjusting the respiration with different rates for different plant components at the same N concentration. Since insufficient N can potentially give rise to lags in plant phenology, the phenological scheme is also adjusted in response to N availability. All these considerations ensure a more comprehensive incorporation of N regulations to plant growth and C cycling. This new approach has been tested systematically to assess the effects of this coupling framework and N limitation on the terrestrial carbon cycle. Long-term measurements from flux tower sites with different PFTs and global satellite-derived products are employed as references to assess these effects. The results show a general improvement with the new plant C–N coupling framework, with more consistent emergent properties, such as GPP and leaf area index (LAI), compared to the observations. The main improvements occur in tropical Africa and boreal regions, accompanied by a decrease in the bias in global GPP and LAI by 16.3 % and 27.1 %, respectively.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1972

Advanced techniques for determining long term compatibility of materials with propellants

The search for advanced measurement techniques for determining long term compatibility of materials with propellants was conducted in several parts. A comprehensive survey of the existing measurement and testing technology for determining material-propellant interactions was performed. Selections were made from those existing techniques which were determined could meet or be made to meet the requirements. Areas of refinement or changes were recommended for improvement of others. Investigations were also performed to determine the feasibility and advantages of developing and using new techniques to achieve significant improvements over existing ones. The most interesting demonstration was that of the new technique, the volatile metal chelate analysis. Rivaling the neutron activation analysis in terms of sensitivity and specificity, the volatile metal chelate technique was fully demonstrated.

Green, R. L.↗
NASA NTRS1977

Microwave multispectral investigations of snow

A long term observational program on microwave emission and scatter behavior under controlled conditions, was started at a high altitude alpine test site. All stages of development of snow cover during the whole season are under investigation. The study was done to achieve required knowledge on microwave radiative properties of snow for optimization of the microwave payloads of air and spaceborne snow sensors and for the interpretation of large scale snow maps obtained by these sensors. Preliminary results of the first month obtained with radiometers at 4.9, 10.5, 21 and 36 GHz are presented.

Schanda, E.↗
NASA NTRS1977

Communications Link Characterization Experiment (CLCE), volume 3

The results of data which were acquired, reduced and analyzed as of June 1977, from the Communications Link Characterization Experiment while utilizing the Communications Link Characterization Experiment while utilizing the Communications Technology Satellite is presented. The long term yearly and worst month propagation data from both stations are presented for the defined yearly period and the test results of the Goddard Television Experiment are described. The data for the continuing path length analysis are updated. Progress on the continuing analysis of utilizing the weather radars for attenuation prediction is given and the concept of the weather radar ratio is presented.

Source record↗
NASA NTRS1979

Force and impulse measurement

Practices are outlined for the design, installation, checkout, calibration, and operation of a thrust measurement system to be used during tests of a liquid monopropellant rocket engine. Appendixes include: (1) thrust measurement system elemental uncertainties; (2) short- and long-term thrust measurement system uncertainty; and (3) shunt calibration of force transducers.

Source record↗
NASA NTRS1979

Pressure measurement

Practices are outlined for the design, installation, checkout, calibration, and operation of a pressure measuring system to be used during tests of a liquid monopropellant rocket engine. Appendixes include: (1) pressure measurement system elemental uncertainties; (2) short- and long-term pressure measurement system uncertainty; (3) shunt calibration of pressure transducers; (4) special considerations for vacuum measurement; and (5) methods of determining the dynamic characteristics of pressure transducers. Design guidelines are provided for the critical components of each portion of the system to provide a pressure measurement system which meets the performance criteria specified.

Source record↗