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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Analysis of MIR Condensate and Potable Water

Approximately fifty percent of the potable water supplied to the Russian cosmonauts, American astronauts, and other occupants of the current Russian Mir Space Station is produced by the direct recycle of water from humidity condensate. The remainder comes from ground supplied potable water that is delivered on a Progress resupply spacecraft, or processed fuel cell water transferred from the Shuttle. Reclamation of water for potable and hygiene purposes is considered essential for extended duration missions in order to avoid massive costs associated with resupplying water from the ground. The Joint U.S/Russian Phase 1 program provided the U.S. the first opportunity to evaluate the performance of water reclamation hardware in microgravity. During the Phase I program, the U.S. collected recycled water, stored water, and humidity condensate samples for chemical and microbial evaluation. This experiment was conducted to determine the potability of the water supplied on Mir, to assess the reliability of the water reclamation and distribution systems, and to aid in developing water quality monitoring standards for International Space Station.

Pierre, L. M.↗
NASA NTRS1985

Phase change water processing for Space Station

The use of a vapor compression distillation subsystem (VCDS) for water recovery on the Space Station is analyzed. The self-contained automated system can process waste water at a rate of 32.6 kg/day and requires only 115 W of electric power. The improvements in the mechanical components of VCDS are studied. The operation of VCDS in the normal mode is examined. The VCDS preprototype is evaluated based on water quality, water production rate, and specific energy. The relation between water production rate and fluids pump speed is investigated; it is concluded that a variable speed fluids pump will optimize water production. Components development and testing currently being conducted are described. The properties and operation of the proposed phase change water processing system for the Space Station, based on vapor compression distillation, are examined.

Zdankiewicz, E. M.↗
NASA NTRS2006

Global Positioning System (GPS) Precipitable Water in Forecasting Lightning at Spaceport Canaveral

This paper evaluates the use of precipitable water (PW) from Global Positioning System (GPS) in lightning prediction. Additional independent verification of an earlier model is performed. This earlier model used binary logistic regression with the following four predictor variables optimally selected from a candidate list of 23 candidate predictors: the current precipitable water value for a given time of the day, the change in GPS-PW over the past 9 hours, the KIndex, and the electric field mill value. This earlier model was not optimized for any specific forecast interval, but showed promise for 6 hour and 1.5 hour forecasts. Two new models were developed and verified. These new models were optimized for two operationally significant forecast intervals. The first model was optimized for the 0.5 hour lightning advisories issued by the 45th Weather Squadron. An additional 1.5 hours was allowed for sensor dwell, communication, calculation, analysis, and advisory decision by the forecaster. Therefore the 0.5 hour advisory model became a 2 hour forecast model for lightning within the 45th Weather Squadron advisory areas. The second model was optimized for major ground processing operations supported by the 45th Weather Squadron, which can require lightning forecasts with a lead-time of up to 7.5 hours. Using the same 1.5 lag as in the other new model, this became a 9 hour forecast model for lightning within 37 km (20 NM)) of the 45th Weather Squadron advisory areas. The two new models were built using binary logistic regression from a list of 26 candidate predictor variables: the current GPS-PW value, the change of GPS-PW over 0.5 hour increments from 0.5 to 12 hours, and the K-index. The new 2 hour model found the following for predictors to be statistically significant, listed in decreasing order of contribution to the forecast: the 0.5 hour change in GPS-PW, the 7.5 hour change in GPS-PW, the current GPS-PW value, and the KIndex. The new 9 hour forecast model found the following five independent variables to be statistically significant, listed in decreasing order of contribution to the forecast: the current GPSPW value, the 8.5 hour change in GPS-PW, the 3.5 hour change in GPS-PW, the 12 hour change in GPS-PW, and the K-Index. In both models, the GPS-PW parameters had better correlation to the lightning forecast than the K-Index, a widely used thunderstorm index. Possible future improvements to this study are discussed.

Kehrer, Kristen C.↗
DOE OSTI2021

Energy Evaluation of Electron Beam Treatment of Perfluoroalkyl Substances in Water: A Critical Review

Due to their recalcitrant nature and ubiquitous use, per- and polyfluoroalkyl substances (PFAS) will continue to be major water treatment hurdles. Although effective water treatment technologies exist for physical removal of many PFAS from water (e.g., activated carbon and ion-exchange resin), a PFAS-concentrated waste stream is generated as an end product that can potentially reintroduce PFAS back into the environment. Thus, there is an increased interest in developing destructive technologies to decompose and mineralize PFAS directly in water or in these waste streams. High energy electron beam (e-beam) accelerators have been used for water treatment to degrade a wide range of recalcitrant contaminants, including PFAS, since the 1960s. However, large-scale applications of e-beam for water treatment are restricted due to its high energy consumption and inability to treat large flow rates. Considering there are very few available technologies for destructive removal of PFAS, this study provides a critical review on the treatment of PFAS by direct irradiation of contaminated water by e-beam from an energy consumption point of view. To date, very limited studies have been conducted to investigate the success of this technology to treat PFAS. Results from the limited studies were not directly comparable due to the variation in operating conditions and water quality parameters used in the studies. Here, for the first time, we develop and apply the concept of electrical energy per order (EE/O) to assess the performance of e-beam for PFAS treatment. Results show that EE/O is a better performance parameter than the G value of e-beam for interstudy comparisons and to evaluate the effects of water quality and operating parameters on e-beam performance. We additionally developed a kinetic scheme to predict the performance of e-beam to treat PFAS and revealed that the competition between species to react with aqueous electrons is the determinant factor influencing PFAS degradation efficiency. Comparison of EE/O values of e-beam (range: 31–176 kWh m –3 order –1 ) with other destructive technologies (range: 5–9595 kWh m –3 order –1 ) suggest that e-beam, for PFAS treatment, is a promising approach under favorable conditions. Furthermore, this review further elucidates the feasibility and limitations of e-beam technology that could be improved upon to potentially make e-beam viable for large-scale water treatment applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Evaluating the combined effects of light and water availability on the early growth and physiology of Tamarindus indica : Implications for restoration

Abstract Premise The tamarind tree (Tamarindus indica) is a species of significant cultural, economic, and ecological value, with a pantropical distribution. However, the tamarind is experiencing a decline in wild populations in its native range, but the reasons for its decline remain unknown. Methods We examined the critical early life‐history stages for tamarind establishment to understand how varying levels of light and water availability and watering frequency affect its regeneration. Through three greenhouse experiments, we assessed the impact of these resources on the germination, survival, growth, and physiological responses of tamarind seedlings and saplings. Results Water availability was critical for seed germination, but not light levels or pre‐germination treatments. Light was the primary limiting factor for seedling growth. Tamarinds in high light availability grew taller, had more biomass and larger diameter, but the effect of light was modulated by water availability, indicating that there was an interaction between both resources. Water and light affected specific leaf area and leaf dry matter content but not biomass allocation, root‐to‐shoot ratio, or stomatal conductance. Water availability influenced sapling growth, but watering frequency did not, indicating a resilience of tamarind saplings to changes in rainfall periodicity but a sensitivity to total rainfall amounts. Conclusions Our study underscores the importance of considering both light and water availability in tamarind restoration efforts and contribute to understanding plant responses and trade‐offs under different levels of critical resources. Our findings will inform conservation strategies to support the regeneration and long‐term survival ofTamarindus indicain its native habitats.

Plant Sciences↗
NASA NTRS1972

Evaluation of factors affecting resolution of shallow water bottom features

To ensure good aerial photography, the effects that factors such as submergence depth, sun angle, film and filter type, exposure, aircraft altitude, and polarization have on the photographic resolution of an underwater object must be determined. Various subjects were photographed, such as the deck of a small submersible, colored and gray scale panels, and natural bottom features. No underwater resolution target was used.

Mason, C. C.↗
NASA NTRS1978

Development and evaluation of a helicopter-borne water-quality monitoring system

A small, helicopter-borne water-quality monitoring package is being developed by the NASA/EPA using a combination of basic in situ water quality sensors and physical sample collector technology. The package is a lightweight system which can be carried and operated by one person as a passenger in a small helicopter typically available by rental at commercial airports. Real-time measurements are made by suspending the water quality monitoring package with a cable from the hovering helicopter. Designed primarily for use in rapidly assessing hazardous material spills in inland and coastal zone water bodies, the system can survey as many as 20 data stations up to 1.5 kilometers apart in 1 hour. The system provides several channels of sensor data and allows for the addition of future sensors. The system will also collect samples from selected sites with sample collection on command. An EPA Spill Response Team member can easily transport, deploy, and operate the water quality monitoring package to determine the distribution, movement, and concentration of the spilled material in the water body.

Wallace, J. W.↗
NASA NTRS1985

Parametric evaluation of ball milling of SiC in water

A statistically designed experiment was conducted to determine optimum conditions for ball milling alpha-SiC in water. The influence of pH adjustment, volume percent solids loading, and mill rotational speed on grinding effectiveness was examined. An equation defining the effect of those milling variables on specific surface area was obtained. The volume percent solids loading of the slurry had the greatest influence on the grinding effectiveness in terms of increase in specific surface area. As grinding effectiveness improved, mill and media wear also increased. Contamination was minimized by use of sintered alpha-SiC milling hardware.

Kiser, J. D.↗
NASA NTRS1985

Parametric evaluation of ball milling of SiC in water

A statistically designed experiment was conducted to determine optimum conditions for ball milling alpha-SiC in water. The influence of pH adjustment, volume percent solids loading, and mill rotational speed on grinding effectiveness was examined. An equation defining the effect of those milling variables on specific surface area was obtained. The volume percent solids loading of the slurry had the greatest influence on the grinding effectiveness in terms of increase in specific surface area. As grinding effectiveness improved, mill and media wear also increased. Contamination was minimized by use of sintered alpha-SiC milling hardware.

Kiser, J. D.↗
NASA NTRS1991

Response of vegetation indices to changes in three measures of leaf water stress

The responses of vegetation indices to changes in water stress were evaluated in two separate laboratory experiments. In one experiment the normalized difference vegetation index (NDVI), the near-IR to red ratio (near-IR/red), the Infrared Index (II), and the Moisture Stress Index (MSI) were more highly correlated to leaf water potential in lodgepole pine branches than were the Leaf Water Content Index (LWCI), the mid-IR ratio (Mid-IR), or any of the single Thematic Mapper (TM) bands. In the other experiment, these six indices and the TM Tasseled Cap brightness, greenness, and wetness indices responded to changes in leaf relative water content (RWC) differently than they responded to changes in leaf water content (WC) of three plant species, and the responses were dependent on how experimental replicates were pooled. With no pooling, the LWCI was the most highly correlated index to both RWC and WC among replications, followed by the II, MSI, and wetness. Only the LWCI was highly correlated to RWC and WC when replications were pooled within species. With among species pooling the LWCI was the only index highly correlated with RWC, while the II, MSI, Mid-IR, and wetness were most highly correlated with WC.

Cohen, Warren B.↗
NASA NTRS2011

Evaluation of Technologies to Prevent Precipitation During Water Recovery from Urine

The International Space Station (ISS) Urine Processor Assembly (UPA) experienced a hardware failure in the Distillation Assembly (DA) in October 2010. Initially the UPA was operated to recover 85% of the water from urine through distillation, concentrating the contaminants in the remaining urine. The DA failed due to precipitation of calcium sulfate (gypsum) which caused a loss of UPA function. The ISS UPA operations have been modified to only recover 70% of the water minimizing gypsum precipitation risk but substantially increasing water resupply needs. This paper describes the feasibility assessment of several technologies (ion exchange, chelating agents, threshold inhibitors, and Lorentz devices) to prevent gypsum precipitation. The feasibility assessment includes the development of assessment methods, chemical modeling, bench top testing, and validation testing in a flight-like ground UPA unit. Ion exchange technology has been successfully demonstrated and has been recommended for further development. The incorporation of the selected technology will enable water recovery to be increased from 70% back to the original 85% and improve the ISS water balance.

Broyan, James L., Jr.↗
NASA NTRS2015

Evaluation of Radar Vegetation Indices for Vegetation Water Content Estimation Using Data from a Ground-Based SMAP Simulator

Vegetation water content (VWC) is an important component of microwave soil moisture retrieval algorithms. This paper aims to estimate VWC using L band active and passive radar/radiometer datasets obtained from a NASA ground-based Soil Moisture Active Passive (SMAP) simulator known as ComRAD (Combined Radar/Radiometer). Several approaches to derive vegetation information from radar and radiometer data such as HH, HV, VV, Microwave Polarization Difference Index (MPDI), HH/VV ratio, HV/(HH+VV), HV/(HH+HV+VV) and Radar Vegetation Index (RVI) are tested for VWC estimation through a generalized linear model (GLM). The overall analysis indicates that HV radar backscattering could be used for VWC content estimation with highest performance followed by HH, VV, MPDI, RVI, and other ratios.

soil moisture↗
DOE OSTI2020

Tracking Seasonal and Interannual Variability in Photosynthetic Downregulation in Response to Water Stress at a Temperate Deciduous Forest

Abstract The understanding and modeling of photosynthetic dynamics affected by climate variability can be highly uncertain. In this paper, we examined a well‐characterized eddy covariance site in a drought‐prone temperate deciduous broadleaf forest combining tower measurements and satellite observations. We find that an increase in spring temperature usually leads to enhanced spring gross primary production (GPP), but a GPP reduction in late growing season due to water limitation. We evaluated how well a coupled fluorescence‐photosynthesis model (SCOPE) and satellite data sets track the interannual and seasonal variations of tower GPP from 2007 to 2016. In SCOPE, a simple stress factor scaling of Vcmax as a linear function of observed predawn leaf water potential ( ψ pd ) shows a good agreement between modeled and measured interannual variations in both GPP and solar‐induced chlorophyll fluorescence (SIF) from the Global Ozone Monitoring Experiment‐2 (GOME‐2). The modeled and satellite‐observed changes in SIF yield are ~30% smaller than corresponding changes in light use efficiency (LUE) under severe stress, for which a common linear SIF to GPP scaling would underestimate the stress reduction in GPP. Overall, GOME‐2 SIF tracks interannual tower GPP variations better than satellite vegetations indices (VIs) representing canopy “greenness.” However, it is still challenging to attribute observed SIF variations unequivocally to greenness or physiological changes due to large GOME‐2 footprint. Higher‐resolution SIF data sets (e.g., TROPOMI) already show the potential to well capture the downregulation of late‐season GPP and could pave the way to better disentangle canopy structural and physiological changes in the future.

He, Liyin↗
NASA NTRS1981

Evaluation of the effects of a freeze/thaw environment on cellular glass

Using the evaluation criteria of water vapor permeability and conformability, a protective butylrubber/silicone conformal coating system was selected for use on Foamglas substrates in a freeze/thaw environment. The selection of a specific freeze/thaw cycle which closely models field conditions is discussed. A sampling plan is described which allows independent evaluation of the effects of conformal coatings, cycle number and location within the environmental chamber. The results of visual examination, measurement of density, modulus of rupture and Young's modulus are reported. Based upon statistical evaluation of the experimental results, it is concluded that no degradation in mechanical properties of either coated or uncoated Foamglas occurred within the duration of the test (53 freeze/thaw cycles).

Frickland, P.↗
DOE OSTI2025

Assessing Heterogeneity of Surface Water Temperature Following Stream Restoration and a High-Intensity Fire from Thermal Imagery

Thermal heterogeneity of rivers is essential to support freshwater biodiversity. Salmon behaviorally thermoregulate by moving from patches of warm water to cold water. When implementing river restoration projects, it is essential to monitor changes in temperature and thermal heterogeneity through time to assess the impacts to a river’s thermal regime. Lightweight sensors that record both thermal infrared (TIR) and multispectral data carried via unoccupied aircraft systems (UASs) present an opportunity to monitor temperature variations at high spatial (<0.5 m) and temporal resolution, facilitating the detection of the small patches of varying temperatures salmon require. Here, we present methods to classify and filter visible wetted area, including a novel procedure to measure canopy cover, and extract and correct radiant surface water temperature to evaluate changes in the variability of stream temperature pre- and post-restoration followed by a high-intensity fire in a section of the river corridor of the South Fork McKenzie River, Oregon. We used a simple linear model to correct the TIR data by imaging a water bath where the temperature increased from 9.5 to 33.4 °C. The resulting model reduced the mean absolute error from 1.62 to 0.35 °C. We applied this correction to TIR-measured temperatures of wetted cells classified using NDWI imagery acquired in the field. We found warmer conditions (+2.6 °C) after restoration (p < 0.001) and median absolute deviation for pre-restoration (0.30) to be less than both that of post-restoration (0.85) and post-fire (0.79) orthomosaics. In addition, there was statistically significant evidence to support the hypothesis of shifts in temperature distributions pre- and post-restoration (KS test 2009 vs. 2019, p < 0.001, D = 0.99; KS test 2019 vs. 2021, p < 0.001, D = 0.10). Moreover, we used a Generalized Additive Model (GAM) that included spatial and environmental predictors (i.e., canopy cover calculated from multispectral NDVI and photogrammetrically derived digital elevation model) to model TIR temperature from a transect along the main river channel. This model explained 89% of the deviance, and the predictor variables showed statistical significance. Collectively, our study underscored the potential of a multispectral/TIR sensor to assess thermal heterogeneity in large and complex river systems.

Barker, Matthew I. (ORCID:0000000252864930)↗
DOE OSTI2021

Nondestructive Evaluation (NDE) of Cable Moisture Exposure using Frequency Domain Reflectometry (FDR)

This Pacific Northwest National Laboratory (PNNL) milestone report assesses the capability of frequency domain reflectometry (FDR) to determine electrical cable submergence using PNNL’s Accelerated and Real-Time Environmental Nodal Assessment (ARENA) cable/motor test bed. This work includes a review of relevant literature as well as experimental tests. Nuclear power facilities have experienced various electrical cable failures related to water exposure. The current industry response involves actions to de-water cable vaults, manholes, and other cable locations. These efforts require considerable expenditure of resources, which makes it desirable for the industry to have information on cable condition and history regarding their submergence and water exposure (Mantey 2012). Two tests that are gaining favor within the nuclear industry are time-domain reflectometry (TDR) and FDR. These are low-voltage nondestructive tests that can be applied at a cable end. Testing from the cable end is important because local inspection along the cable length is very difficult due to cables being routed within trays, conduits, underground, and through walls. Both TDR and FDR techniques have been shown to locate cable insulation damage due to thermal, radiation, and mechanical damage. FDR measurements are also more sensitive than TDR to temperature changes, low-bend radius bends, and cable contact with various materials, including conductive materials like steel and water. This work evaluates the feasibility to extend FDR testing to characterizing whether an electrical cable is submerged or not and where it may be submerged using PNNL’s ARENA cable/motor test bed.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗