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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Use of LANDSAT images of vegetation cover to estimate effective hydraulic properties of soils

The estimation of the spatially variable surface moisture and heat fluxes of natural, semivegetated landscapes is difficult due to the highly random nature of the vegetation (e.g., plant species, density, and stress) and the soil (e.g., moisture content, and soil hydraulic conductivity). The solution to that problem lies, in part, in the use of satellite remotely sensed data, and in the preparation of those data in terms of the physical properties of the plant and soil. The work was focused on the development and testing of a stochastic geometric canopy-soil reflectance model, which can be applied to the physically-based interpretation of LANDSAT images. The model conceptualizes the landscape as a stochastic surface with bulk plant and soil reflective properties. The model is particularly suited for regional scale investigations where the quantification of the bulk landscape properties, such as fractional vegetation cover, is important on a pixel by pixel basis. A summary of the theoretical analysis and the preliminary testing of the model with actual aerial radiometric data is provided.

Eagleson, Peter S.↗
NASA NTRS1994

Constraints on hydrothermal heat flux through the oceanic lithosphere from global heat flow

A significant discrepancy exists between the heat flow measured at the seafloor and the higher values predicted by thermal models of the cooling lithosphere. This discrepancy is generally interpreted as indicating that the upper oceanic crust is cooled significantly by hydrothermal circulation. The magnitude of this heat flow discrepancy is the primary datum used to estimate the volume of hydrothermal flow, and the variation in the discrepancy with lithospheric age is the primary constraint on how the hydrothermal flux is divided between near-ridge and off-ridge environments. The resulting estimates are important for investigation of both the thermal structure of the lithosphere and the chemistry of the oceans. We reevaluate the magnitude and age variation of the discrepancy using a global heat flow data set substantially larger than in earlier studies, and the GDHI (Global Depth and Heat Flow) model that better predicts the heat flow. We estimate that of the predicted global oceanic heat flux of 32 x 10(exp 12) W, 34% (11 x 10(exp 12) W) occurs by hydrothermal flow. Approximately 30% of the hydrothermal heat flux occurs in crust younger than 1 Ma, so the majority of this flux is off-ridge. These hydrothermal heat flux estimates are upper bounds, because heat flow measurements require sediment at the site and so are made preferentially at topographic lows, where heat flow may be depressed. Because the water temperature for the near-ridge flow exceeds that for the off-ridge flow, the near-ridge water flow will be even a smaller fraction of the total water flow. As a result, in estimating fluxes from geochemical data, use of the high water temperatures appropriate for the ridge axis may significantly overestimate the heat flux for an assumed water flux or underestimate the water flux for an assumed heat flux. Our data also permit improved estimates of the 'sealing' age, defined as the age where the observed heat flow approximately equals that predicted, suggesting that hydrothermal heat transfer has largely ceased. Although earlier studies suggested major differences in sealing ages for different ocean basins, we find that the sealing ages for the Atlantic, Pacific, and Indian oceans are similar and consistent with the sealing age for the entire data set, 65 +/- 10 Ma. The previous inference of a young (approximately 20 Ma) sealing age for the Pacific appears to have biased downward several previous estimates of the global hydrothermal flux. The heat flow data also provide indirect evidence for the mechanism by which the hydrothermal heat flux becomes small, which has often been ascribed to isolation of the igneous crust from seawater due to the hydraulic conductivity of the intervening sediment. We find, however, that even the least sedimented sites show the systematic increase of the ratio of observed to predicted heat flow with age, although the more sedimented sites have a younger sealing age. Moreover, the heat flow discrepancy persists at heavily sedimented sites until approximately 50 Ma. It thus appears that approximately 100-200 m of sediment is neither necessary nor sufficient to stop hydrothermal heat transfer. We therefore conclude that the age of the crust is the primary control on the fraction of heat transported by hydrothermal flow and that sediment thickness has a lesser effect. This inference is consistent with models in which hydrothermal flow decreases with age due to reduced crustal porosity and hence permeability.

Stein, Carol A.↗
NASA NTRS1997

Application of Multitemporal Remotely Sensed Soil Moisture for the Estimation of Soil Physical Properties

This paper demonstrates the use of multitemporal soil moisture derived from microwave remote sensing to estimate soil physical properties. The passive microwave ESTAR instrument was employed during June 10-18, 1992, to obtain brightness temperature (TB) and surface soil moisture data in the Little Washita watershed, Oklahoma. Analyses of spatial and temporal variations of TB and soil moisture during the dry-down period revealed a direct relationship between changes in T and soil moisture and soil physical (viz. texture) and hydraulic (viz. saturated hydraulic conductivity, K(sat)) properties. Statistically significant regression relationships were developed for the ratio of percent sand to percent clay (RSC) and K(sat), in terms of change components of TB and surface soil moisture. Validation of results using field measured values and soil texture map indicated that both RSC and K(sat) can be estimated with reasonable accuracy. These findings have potential applications of microwave remote sensing to obtain quick estimates of the spatial distributions of K(sat), over large areas for input parameterization of hydrologic models.

Mattikalli, N. M.↗
NASA NTRS1997

Microwave Remote Sensing of Soil Moisture for Estimation of Soil Properties

Surface soil moisture dynamics was derived using microwave remote sensing, and employed to estimate soil physical and hydraulic properties. The L-band ESTAR radiometer was employed in an airborne campaign over the Little Washita watershed, Oklahoma during June 10-18, 1992. Brightness temperature (TB) data were employed in a soil moisture inversion algorithm which corrected for vegetation and soil effects. Analyses of spatial TB and soil moisture dynamics during the dry-down period revealed a direct relationship between changes in TB, soil moisture and soil texture. Extensive regression analyses were carried out which yielded statistically significant quantitative relationships between ratio of percent sand to percent clay (RSC, a term derived to quantify soil texture) and saturated hydraulic conductivity (Ksat) in terms of change components of TB and surface soil moisture. Validation of results indicated that both RSC and Ksat can be estimated with reasonable accuracy. These findings have potential applications for deriving spatial distributions of RSC and Ksat over large areas.

Mattikalli, Nandish M.↗
NASA NTRS2001

Representation of Stormflow and a More Responsive Water Table in a TOPMODEL-Based Hydrology Model

This study presents two new modeling strategies. First, a methodology for representing the physical process of stormflow within a TOPMODEL framework is developed. In using this approach, discharge at quickflow time scales is simulated and a fuller depiction of hydrologic activity is brought about. Discharge of water from the vadose zone is permitted in a physically realistic manner without a priori assumption of the level within the soil column at which stormflow saturation can take place. Determination of the stormflow contribution to discharge is made using the equation for groundwater flow. No new parameters are needed. Instead, regions of near saturation that develop during storm events, producing vertical recharge, are allowed to contribute to soil column discharge. These stormflow contributions to river runoff, as for groundwater flow contributions, are a function of catchment topography and local hydraulic conductivity at the depth of these regions of near saturation. The second approach improves groundwater flow response through a reduction of porosity and field capacity with depth in the soil column. Large storm events are better captured and a more dynamic water table develops with application of this modified soil column profile (MSCP). The MSCP predominantly reflects soil depth differences in upland and lowland regions of a watershed. Combined, these two approaches - stormflow and the MSCP - provide a more accurate representation of the time scales at which soil column discharge responds and a more complete depiction of hydrologic activity. Storm events large and small are better simulated, and some of the biases previously evident in TOPMODEL simulations are reduced.

Shaman, Jeffrey↗
NASA NTRS1988

Mechanism of rapid suppression of cell expansion in cucumber hypocotyls after blue-light irradiation

Rapid suppression of hypocotyl elongation by blue light in cucumber (Cucumis sativus L.) was studied to examine possible hydraulic and wall changes responsible for diminished growth. Cell-sap osmotic pressure, measured by vapor-pressure osmometry, was not decreased by blue light; turgor pressure, measured by the pressure-probe technique, remained constant during the growth inhibition; and stem hydraulic conductance, measured by dynamic and static methods, was likewise unaffected by blue light. Wall yielding properties were assessed by the pressure-block technique for in-vivo stress relaxation. Blue light reduced the initial rate of relaxation by 77%, but had little effect on the final amount of relaxation. The results demonstrate that blue irradiation acts to decrease the wall yielding coefficient, but not the yield threshold. Stress-strain (Instron) analysis showed that irradiation of the seedlings had little effect on the mechanical extensibilities of the isolated wall. The results indicate that blue light can reduce cell-wall loosening without affecting bulk viscoelastic properties, and indicate a chemorheological mechanism of cell-wall expansion.

NASA Discipline Number 40-30↗
NASA NTRS1990

Gravitropism of cucumber hypocotyls: biophysical mechanism of altered growth

The biophysical basis for the changes in cell elongation rate during gravitropism was examined in aetiolated cucumber (Cucumis sativus L.) hypocotyls. Bulk osmotic pressures on the two sides of the stem and in the epidermal cells were not altered during the early time course of gravitropism. By the pressure-probe technique, a small increase in turgor (0.3 bar, 30 kPa) was detected on the upper (inhibited) side, whereas there was a negligible decrease in turgor on the lower (stimulated) side. These small changes in turgor and water potential appeared to be indirect, passive consequences of the altered growth and the small resistance for water movement from the xylem, and indicated that the change in growth was principally due to changes in wall properties. The results indicate that the hydraulic conductance of the water-transport pathway was large (.25 h-1 bar-1) and the water potential difference supporting cell expansion was no greater than 0.3 bar (30 kPa). From pressure-block experiments, it appeared that upon gravitropic stimulation (1) the yield threshold of the lower half of the stem did not decrease and (2) the wall on the upper side of the stem was not made more rigid by a cross-linking process. Mechanical measurements of the stress/strain properties of the walls showed that the initial development of gravitropism did not involve an alteration of the mechanical behaviour of the isolated walls. Thus, gravitropism in cucumber hypocotyls occurs principally by an alteration of the wall relaxation process, without a necessary change in wall mechanical properties.

Non-NASA Center↗
NASA NTRS2001

Modeling of two-phase flow in membranes and porous media in microgravity as applied to plant irrigation in space

In traditional applications in soil physics it is convention to scale porous media properties, such as hydraulic conductivity, soil water diffusivity, and capillary head, with the gravitational acceleration. In addition, the Richards equation for water flux in partially saturated porous media also contains a gravity term. With the plans to develop plant habitats in space, such as in the International Space Station, it becomes necessary to evaluate these properties and this equation under conditions of microgravitational acceleration. This article develops models for microgravity steady state two-phase flow, as found in irrigation systems, that addresses critical design issues. Conventional dimensionless groups in two-phase mathematical models are scaled with gravity, which must be assigned a value of zero for microgravity modeling. The use of these conventional solutions in microgravity, therefore, is not possible. This article therefore introduces new dimensionless groups for two-phase models. The microgravity models introduced here determined that in addition to porous media properties, important design factors for microgravity systems include applied water potential and the ratio of inner to outer radii for cylindrical and spherical porous media systems.

Plant Roots/growth & development↗
NASA NTRS1987

Pressure probe study of the water relations of Phycomyces blakesleeanus sporangiophores

The physical characteristics which govern the water relations of the giant-celled sporangiophore of Phycomyces blakesleeanus were measured with the pressure probe technique and with nanoliter osmometry. These properties are important because they govern water uptake associated with cell growth and because they may influence expansion of the sporangiophore wall. Turgor pressure ranged from 1.1 to 6.6 bars (mean = 4.1 bars), and was the same for stage I and stage IV sporangiophores. Sporangiophore osmotic pressure averaged 11.5 bars. From the difference between cell osmotic pressure and turgor pressure, the average water potential of the sporangiophore was calculated to be about -7.4 bars. When sporangiophores were submerged under water, turgor remained nearly constant. We propose that the low cell turgor pressure is due to solutes in the cell wall solution, i.e., between the cuticle and the plasma membrane. Membrane hydraulic conductivity averaged 4.6 x 10(-6) cm s-1 bar-1, and was significantly greater in stage I sporangiophores than in stage IV sporangiophores. Contrary to previous reports, the sporangiophore is separated from the supporting mycelium by septa which prevent bulk volume flow between the two regions. The presence of a wall compartment between the cuticle and the plasma membrane results in anomalous osmosis during pressure clamp measurements. This behavior arises because of changes in solute concentration as water moves into or out of the wall compartment surrounding the sporangiophore. Theoretical analysis shows how the equations governing transient water flow are altered by the characteristics of the cell wall compartment.

NASA Discipline Number 40-30↗
NASA NTRS1998

Documentation of angiotensin II receptors in glomerular epithelial cells

Angiotensin II decreases glomerular filtration rate, renal plasma flow, and glomerular capillary hydraulic conductivity. Although angiotensin II receptors have been demonstrated in mesangial cells and proximal tubule cells, the presence of angiotensin II receptors in glomerular epithelial cells has not previously been shown. Previously, we have reported that angiotensin II caused an accumulation of cAMP and a reorganization of the actin cytoskeleton in cultured glomerular epithelial cells. Current studies were conducted to verify the presence of angiotensin II receptors by immunological and non-peptide receptor ligand binding techniques and to ascertain the activation of intracellular signal transduction in glomerular epithelial cells in response to angiotensin II. Confluent monolayer cultures of glomerular epithelial cells were incubated with angiotensin II, with or without losartan and/or PD-123,319 in the medium. Membrane vesicle preparations were obtained by homogenization of washed cells followed by centrifugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of membrane proteins followed by multiscreen immunoblotting was used to determine the presence of angiotensin II receptor type 1 (AT1) or type 2 (AT2). Angiotensin II-mediated signal transduction in glomerular epithelial cells was studied by measuring the levels of cAMP, using radioimmunoassay. Results obtained in these experiments showed the presence of both AT1 and AT2 receptor types in glomerular epithelial cells. Angiotensin II was found to cause an accumulation of cAMP in glomerular epithelial cells, which could be prevented only by simultaneous use of losartan and PD-123,319, antagonists for AT1 and AT2, respectively. The presence of both AT1 and AT2 receptors and an increase in cAMP indicate that glomerular epithelial cells respond to angiotensin II in a manner distinct from that of mesangial cells or proximal tubular epithelial cells. Our results suggest that glomerular epithelial cells participate in angiotensin II-mediated control of the glomerular filtration barrier.

Non-NASA Center↗
NASA NTRS2005

Measurement of hydraulic characteristics of porous media used to grow plants in microgravity

Understanding the effect of gravity on hydraulic properties of plant growth medium is essential for growing plants in space. The suitability of existing models to simulate hydraulic properties of porous medium is uncertain due to limited understanding of fundamental mechanisms controlling water and air transport in microgravity. The objective of this research was to characterize saturated and unsaturated hydraulic conductivity (K) of two particle-size distributions of baked ceramic aggregate using direct measurement techniques compatible with microgravity. Steady state (Method A) and instantaneous profile measurement (Method B) methods for K were used in a single experimental unit with horizontal flow through thin sections of porous medium providing an earth-based analog to microgravity. Comparison between methods was conducted using a crossover experimental design compatible with limited resources of space flight. Satiated (natural saturation) K ranged from 0.09 to 0.12 cm s-1 and 0.5 to >1 cm s-1 for 0.25- to 1- and 1- to 2-mm media, respectively. The K at the interaggregate/intraaggregate transition was approximately 10(-4) cm s-1 for both particle-size distributions. Significant differences in log(10)K due to method and porous medium were less than one order of magnitude and were attributed to variability in air entrapment. The van Genuchten/Mualem parametric models provided an adequate prediction of K of the interaggregate pore space, using residual water content for that pore space. The instantaneous profile method covers the range of water contents relevant to plant growth using fewer resources than Method A, all advantages for space flight where mass, volume, and astronaut time are limited.

NASA Center JSC↗
NASA NTRS2005

Physical and hydraulic properties of baked ceramic aggregates used for plant growth medium

Baked ceramic aggregates (fritted clay, arcillite) have been used for plant research both on the ground and in microgravity. Optimal control of water and air within the root zone in any gravity environment depends on physical and hydraulic properties of the aggregate, which were evaluated for 0.25-1-mm and 1-2-mm particle size distributions. The maximum bulk densities obtained by any packing technique were 0.68 and 0.64 g cm-3 for 0.25-1-mm and 1-2-mm particles, respectively. Wettable porosity obtained by infiltration with water was approximately 65%, substantially lower than total porosity of approximately 74%. Aggregate of both particle sizes exhibited a bimodal pore size distribution consisting of inter-aggregate macropores and intra-aggregate micropores, with the transition from macro- to microporosity beginning at volumetric water content of approximately 36% to 39%. For inter-aggregate water contents that support optimal plant growth there is 45% change in water content that occurs over a relatively small matric suction range of 0-20 cm H2O for 0.25-1-mm and 0 to -10 cm H2O for 1-2-mm aggregate. Hysteresis is substantial between draining and wetting aggregate, which results in as much as a approximately 10% to 20% difference in volumetric water content for a given matric potential. Hydraulic conductivity was approximately an order of magnitude higher for 1-2-mm than for 0.25-1-mm aggregate until significant drainage of the inter-aggregate pore space occurred. The large change in water content for a relatively small change in matric potential suggests that significant differences in water retention may be observed in microgravity as compared to earth.

NASA Center JSC↗
NASA NTRS2004

Electrokinetic In Situ Treatment of Metal-Contaminated Soil

An electrokinetic technique has been developed as a means of in situ remediation of soils, sludges, and sediments that are contaminated with heavy metals. Examples of common metal contaminants that can be removed by this technique include cadmium, chromium, zinc, lead, mercury, and radionuclides. Some organic contaminants can also be removed by this technique. In the electrokinetic technique, a low-intensity direct current is applied between electrodes that have been implanted in the ground on each side of a contaminated soil mass. The electric current causes electro-osmosis and migration of ions, thereby moving aqueous-phase subsurface contaminants from one electrode to the other. The half reaction at the anode yields H+, thereby generating an acid front that travels from the anode toward the cathode. As this acid front passes through a given location, the local increase in acidity increases the solubility of cations that were previously adsorbed on soil particles. Ions are transported towards one electrode or the other which one depending on their respective electric charges. Upon arrival at the electrodes, the ionic contaminants can be allowed to become deposited on the electrodes or can be extracted to a recovery system. Surfactants and other reagents can be introduced at the electrodes to enhance rates of removal of contaminants. Placements of electrodes and concentrations and rates of pumping of reagents can be adjusted to maximize efficiency. The basic concept of electrokinetic treatment of soil is not new. What is new here are some of the details of application and the utilization of this technique as an alternative to other techniques (e.g., flushing or bioremediation) that are not suitable for treating soils of low hydraulic conductivity. Another novel aspect is the use of this technique as a less expensive alternative to excavation: The cost advantage over excavation is especially large in settings in which contaminated soil lies near and/or under industrial buildings and therefore excavation would be made even more expensive by the need to prevent damage to numerous underground pipes and cables.

Quinn, Jacqueline↗
NASA NTRS2017

Enhanced Groundwater Recharge Rates and Altered Recharge Sensitivity to Climate Variability Through Subsurface Heterogeneity

Our environment is heterogeneous. In hydrological sciences, the heterogeneity of subsurface properties, such as hydraulic conductivities or porosities, exerts an important control on water balance. This notably includes groundwater recharge, which is an important variable for efficient and sustainable groundwater resources management. Current large-scale hydrological models do not adequately consider this subsurface heterogeneity. Here we show that regions with strong subsurface heterogeneity have enhanced present and future recharge rates due to a different sensitivity of recharge to climate variability compared with regions with homogeneous subsurface properties. Our study domain comprises the carbonate rock regions of Europe, Northern Africa, and the Middle East, which cover 25 of the total land area. We compare the simulations of two large-scale hydrological models, one of them accounting for subsurface heterogeneity. Carbonate rock regions strongly exhibit karstification, which is known to produce particularly strong subsurface heterogeneity. Aquifers from these regions contribute up to half of the drinking water supply for some European countries. Our results suggest that water management for these regions cannot rely on most of the presently available projections of groundwater recharge because spatially variable storages and spatial concentration of recharge result in actual recharge rates that are up to four times larger for present conditions and changes up to five times larger for potential future conditions than previously estimated. These differences in recharge rates for strongly heterogeneous regions suggest a need for groundwater management strategies that are adapted to the fast transit of water from the surface to the aquifers.

water resources↗
NASA NTRSDate not supplied

Utilizing Open-Source Earth Observations to Inform the Toa Baja Municipality’s Flood Risk Mitigation Efforts and Educate the Public

Global climate changes contribute to more intense and frequent tropical storms, subjecting places like Toa Baja, Puerto Rico to critical damage. Known as “the underwater city” due to its propensity to flood, residents of Toa Baja face constant flood risk. During extreme tropical storm events, such as Hurricane Maria in 2017, residents experienced up to 20 feet of inundation. The NASA DEVELOP National Program collaborated with the Municipio Autónomo de Toa Baja, ResilientSEE-PR, and the MIT Urban Risk Lab to supplement 2018 FEMA HEC-RAS flood maps that designate 63% of Toa Baja as a flood plain. This analysis provides a high-resolution interpretation of flood risk through two lenses; susceptibility and vulnerability. For this analysis, susceptibility consists of nine weighted layers: NDVI, landcover, slope, elevation, topographic wetness index, height above nearest drainage, saturated hydraulic conductivity, distance to water, and storm surge. These factors are consistently used to evaluate susceptibility to flood, but their weights vary by analysis. Vulnerability consists of population, informal settlements, and building density, which were given equal weight. Susceptibility and vulnerability were combined to map flood risk. This analysis used a bivariate legend to understand the different levels of risk along a spectrum from low susceptibility and low vulnerability (low risk) to high susceptibility and high vulnerability (high risk). Data processed in Google Earth Engine, which identified historical inundation on various occasions, were used to validate the flood susceptibility layers. Results showed 89% of areas designated as high susceptibility are located within the floodway designated by the FEMA HEC-RAS maps. The eastern region of Toa Baja is most at risk for flooding due to high susceptibility to flooding along with a high density of population, buildings, and informal settlements. The resulting map also reveals the presence of smaller high-risk areas all around the municipality. This analysis provides scientific evidence for flood risk mitigation in Toa Baja by highlighting areas that might be impacted by strong floods in the future. Additionally, these results are communicated in an Esri ArcGIS StoryMap, an accessible platform that can easily inform the public about the flood risk in their neighborhood.

Adriana Le Compte↗
NASA NTRS2021

Maximum entropy modeling to identify physical drivers of shallow snowpack heterogeneity using unpiloted aerial system (UAS) lidar

Understanding the spatial variability of the snowpack is valuable for hydrologists and ecologists seeking to predict hydrological processes in a cold region. Snow distribution is a function of interactions among static variables, such as terrain, vegetation, and soil properties, and dynamic meteorological variables, such as solar radiation, wind speed and direction, and soil moisture. However, identifying the dominant physical drivers responsible for spatial patterns of the snowpack, particularly for ephemeral, shallow snowpacks, has been challenging due to the lack of the high-resolution snowpack and physical variables with high vertical accuracy as well as inherent limitations in traditional approaches. This study uses an Unpiloted Aerial System (UAS) lidar-based snow depth and static variables (1-m spatial resolution) to analyze field-scale spatial structures of snow depth and apply the Maximum Entropy (MaxEnt) model to identify primary controls over open terrain and forests at the University of New Hampshire Thompson Farm Research Observatory, New Hampshire, United States. We found that, among nine topographic and soil variables, plant functional type and terrain roughness contribute up to 80% and 76% of relative importance in the MaxEnt framework to predict locations of deeper or shallower snowpacks, respectively, across a mixed temperate forested and field landscape. Soil variables, such as organic matter and saturated hydraulic conductivity, were also important controls (up to 70% and 81%) on snow depth spatial variations for both open and forested landscapes suggesting spatial variations in soil variables under snow can control thermal transfer among soil, snowpack, and surface-atmosphere. This work contributes to improving land surface and snow models by informing parameterization of the sub-grid scale snow depths, down-scaling remotely sensed snow products, and understanding field scale snow states.

Eunsang Cho↗
NASA NTRSDate not supplied

3d Particle Geometry Characterization of Apollo Regolith Samples Via Laser Diffraction and Dynamic Image Analysis

Establishing a fundamental understanding of regolith mechanics hinges on the characterization of the foundational physical parameters that dictate granular particle interactions both on micro- and macro-scales. Specifically, particle size distribution, particle geometry and grain density govern the geotechnical properties, including compressibility, shear strength, hydraulic conductivity (i.e., permeability), void ratio (i.e., porosity), and thermal conductivity of the lunar regolith. The absence of terrestrial geologic processes on the lunar surface, a lack of water, clay minerals, and organic material in lunar soils, and the narrow compositional range in terms of mineral diversity of the regolith produces a unique problem when attempting to project terrestrial soil mechanics concepts to the lunar surface. Additionally, the occurrence of agglutinates, exclusive to the lunar surface, further disassociates the physical behavior (e.g., particle crushability, flowability, etc.) of regolith from that observed in terrestrial soils.

R. Kovtun↗
NASA NTRS2024

Interim Measures Pilot Study Completion Report, South Repeater Building, Solid Waste Management Unit 121, Hydraulic Containment and Groundwater Treatment System for Per- and Polyfluoroalkyl Substances

This Per- and Polyfluoroalkyl Substances (PFAS) Interim Measures Pilot Study Completion Report was prepared for the National Aeronautics and Space Administration by AECOM Technical Services, Inc. under Contract 80KSC019D0010, Task Order 80KSC021F0096. The purpose of this report is to document the pilot study activities at the South Repeater Building, Solid Waste Management Unit (SWMU) 121. This report details the additional assessment activities completed from June 2023 through November 2023 and the subsequent pilot study completed at the South Repeater Building conducted in December 2023 through February 2024. Initial activities were conducted in accordance with the Pilot Study Work Plan (NASA 2023), submitted to the KSC Remediation Team and accepted by the team on October 26, 2023. The objectives of the pilot study were to: • Provide information on aquifer characteristics and to aid in future modeling and remedial design activities to mitigate off-KSC migration of PFAS compounds. • Develop information on characteristics of the surficial aquifer system, specifically transmissivity, storage coefficient, hydraulic conductivity, and vertical hydraulic conductivity. • Obtain data to support construction and calibration of a groundwater flow model. • Acquire design parameters necessary for future remedial design activities, specifically radius of influence, drawdown, flow rates, and pump settings. The following activities were completed to meet the pilot study objectives: • Groundwater and surface water sampling • Geophysical investigation via Hydraulic Profiling Tool (HPT) and soil sampling • Installation of observation and extraction wells via rotosonic techniques • Slug, step, and pump testing activities • Initial modeling efforts for a groundwater hydraulic containment system. Results of the pilot study and modeling activities are being used in the development of a groundwater containment and treatment system for the site.

PFAS↗