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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Analytical chemistry of nuclear material: case studies from Los Alamos National Laboratory

Presented here are three case studies that demonstrate the breadth of bulk actinide analytical chemistry at Los Alamos National Laboratory (LANL). This laboratory was established during the Manhattan Project and is still considered one of the premier analytical laboratories for special nuclear materials characterization around the globe. First, the analytical chemistry of 238 Pu is presented, showcasing the unique challenges of this high activity isotope. Next, the analysis of 241 AmO 2 is discussed from the perspective of supporting nascent production at LANL. Finally, the analytical chemistry support of the production of plutonium non-destructive assay standards is discussed. Furthermore these examples paint a picture of the analytical capabilities needed to meet the dynamic challenges of LANL’s nuclear programs.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2015

Evaluating the functional importance of secretive species: A case study of aquatic snake predators in isolated wetlands

Abstract Although the need to prioritize limited conservation resources has prompted increased interest in understanding the functional importance of species within ecosystems, species that are infrequently observed are often written off as being unimportant. In this study, we use aquatic snakes as a case study for examining the importance of secretive predators. Most snakes are extremely cryptic and secretive, traits that not only lead to the perception that they are rare, and of minor importance, but also impede attempts to quantify densities. We used high sampling effort and robust‐design capture–recapture analyses to estimate density of aquatic snakes inhabiting an isolated 5.4‐ha wetland in South Carolina, USA . We assessed snake diets and coupled field measurements of growth rates with laboratory‐derived data on mass conversion efficiency to estimate prey consumption by snakes over a 1‐year period. We found a peak density 171 snakes ha −1 of wetland habitat, corresponding to a standing biomass of 7.77 kg ha −1 . We calculated that snakes within the wetland consumed a total of over 200 kg (>55 000 individuals) of amphibian prey annually, translating into >150 000 kJ ha −1 of energy flow from secondary to tertiary consumers within the wetland food web. Further, because many amphibians are primarily terrestrial as adults and are consumed by aquatic snakes only when they return to wetlands to breed, snakes can be responsible for substantial transfer of energy and biomass between terrestrial and aquatic habitats. Our study is one of the first comprehensive evaluations of the importance of snakes as predators and underscores the need to consider snakes in initiatives aimed at preserving overall ecosystem integrity.

Willson, J. D.↗
DOE OSTI2025

Long-Range Transport of Biomass Burning Aerosols from Southern Africa: A Case Study Using Layered Atlantic Smoke Interactions with Clouds Observations

A case study of an incoming biomass burning aerosol plume at Ascension Island is analyzed for the peak of the 2017 fire season using satellites, reanalysis and in situ observations. Measurements from the Atmospheric Radiation Measurement Mobile Facility 1 reveal an abrupt change from relatively clean conditions (~70 parts per billion by volume of carbon monoxide) to a more polluted state (~150 parts per billion by volume of carbon monoxide). Corresponding changes in aerosol size reveal a broadening of size distributions toward larger optical diameters, consistent with the arrival of aged aerosols. Within a 24 h period, black carbon fraction increases ~500% from ~300 ng m e to ~1500 ng m 3 , while light absorption coefficients increase ~300%. Long-range transport of these aerosols is primarily confined between 2 and 5 km above sea level along the northwesterly trade winds. Our results show that the primary driver of increases in aerosol loading over Ascension Island is an intensification of the St. Helena high-pressure system (anticyclone) that leads to a weakening of trade winds and increases westward transport on its northern flank. A better understanding of the complex interactions between air quality, meteorology and long-range aerosol transport is important for future modeling studies focused on aerosol–cloud–radiation interactions over the open ocean and reducing its associated uncertainties.

aerosol size distribution↗
DOE OSTI2020

Chemical Impacts of Potential CO2 and Brine Leakage on Groundwater Quality with Quantitative Risk Assessment: A Case Study of the Farnsworth Unit

Potential leakage of reservoir fluids is considered a key risk factor for geologic CO2 sequestration (GCS), with concerns of their chemical impacts on the quality of overlying underground sources of drinking water (USDWs). Effective risk assessment provides useful information to guide GCS activities for protecting USDWs. In this study, we present a quantified risk assessment case study of an active commercial-scale CO2-enhanced oil recovery (CO2-EOR) and sequestration field, the Farnsworth Unit (FWU). Specific objectives of this study include: (1) to quantify potential risks of CO2 and brine leakage to the overlying USDW quality with response surface methodology (RSM); and (2) to identify water chemistry indicators for early detection criteria. Results suggest that trace metals (e.g., arsenic and selenium) are less likely to become a risk due to their adsorption onto clay minerals; no-impact thresholds based on site monitoring data could be a preferable reference for early groundwater quality evaluation; and pH is suggested as an indicator for early detection of a leakage. This study may provide quantitative insight for monitoring strategies on GCS sites to enhance the safety of long-term CO2 sequestration.

58 GEOSCIENCES↗
NASA NTRS1989

A multipoint case study of high-latitude daytime ULF pulsations

A multipoint case study approach is used to delineate significant morphological differences between, and distinct sources for, two kinds of high-latitude dayside ULF wave activity in the Pc 3 to Pi 1 frequency range. Evidence is presented that narrow-band Pc 3-4 pulsations appear roughly simultaneously at widely spaced locations in the dayside magnetosphere and polar cap and that their occurrence/intensity is controlled by the cone angle of the IMF, while broadband Pi 1 type activity appears to be related closely to precipitation of energetic plasma sheet electrons, hence more localized ionospheric activity. Additional evidence is provided that the cusp/cleft regions play a significant part in the transmission to low altitudes of at least some of the wave energy of solar wind-controlled pulsations.

Engebretson, M. J.↗
NASA NTRS2011

JPL Thermal Design Modeling Philosophy and NASA-STD-7009 Standard for Models and Simulations - A Case Study

The Standard JPL thermal engineering practice prescribes worst-case methodologies for design. In this process, environmental and key uncertain thermal parameters (e.g., thermal blanket performance, interface conductance, optical properties) are stacked in a worst case fashion to yield the most hot- or cold-biased temperature. Thus, these simulations would represent the upper and lower bounds. This, effectively, represents JPL thermal design margin philosophy. Uncertainty in the margins and the absolute temperatures is usually estimated by sensitivity analyses and/or by comparing the worst-case results with "expected" results. Applicability of the analytical model for specific design purposes along with any temperature requirement violations are documented in peer and project design review material. In 2008, NASA released NASA-STD-7009, Standard for Models and Simulations. The scope of this standard covers the development and maintenance of models, the operation of simulations, the analysis of the results, training, recommended practices, the assessment of the Modeling and Simulation (M&S) credibility, and the reporting of the M&S results. The Mars Exploration Rover (MER) project thermal control system M&S activity was chosen as a case study determining whether JPL practice is in line with the standard and to identify areas of non-compliance. This paper summarizes the results and makes recommendations regarding the application of this standard to JPL thermal M&S practices.

thermal blanket performance↗
DOE OSTI2011

Existing Whole-House Solutions Case Study: Deep Energy Retrofit of 1910 House, Portland, Oregon

This case study lists project information, cost and energy efficiency performance data, energy efficiency measures and lessons learned for a 100-year-old home in Portland, Oregon, audited by Pacific Northwest National Laboratory for a deep energy retrofit. New HVAC and extensive insulation upgrades including rigid XPS and new siding over the old lead painted siding, and EPS on the basement walls and in cathedral ceiling helped bring HERS down to 68.

basement↗
DOE OSTI2015

DOE ZERH Case Study: Hammer and Hand, Pumpkin Ridge Passive House, North Plains, OR

Case study of a DOE 2015 Housing Innovation Award winning custom home in the marine climate that got a HERS 49 without PV, or HERS 5 with PV, with 2x4 24” on center walls plus 8” exterior cavity together dense-packed with R-60 cellulose; daylight basement with R-29 rigid EPS foam under slab; vented attic with R-86 blown cellulose; minisplit heat pump; ducted with HRV; 15.5 SEER; 10 HSPF.

Building America↗
DOE OSTI2015

DOE ZERH Case Study: KB Home, Double ZeroHouse 3.0, El Dorado Hill, CA

Case study of a DOE 2015 Housing Innovation Award winning production home in the mixed-dry climate that got a HERS 44 without PV, or HERS -2 with PV, with 2x4 walls 16” on center walls with R-15 cavity plus 1” EPS exterior rigid foam, slab on grade with R-10 slab edge; unvented attic with R-38 blown fiberglass netted to underside of roof deck; 19 SEER heat pump; heat pump water heater; 100% LED.

Building America↗
DOE OSTI2015

DOE ZERH Case Study: Palo Duro Homes, Via del Cielo, Santa Fe, NM

Case study of a DOE 2015 Housing Innovation Award winning production home in the mixed-dry climate that got a HERS 48 without PV, with 2x6 24” on center walls with R-21 blown fiberglass; slab foundation with R-10 under slab and R-5rigid foam at slab edge; vented attic with R-75 blown fiberglass; ducted minisplit heat pump 16.5 SEER, 9.5 HSPF.

Building America↗
DOE OSTI2017

A Case Study in Market Transformation for Residential Energy Efficiency Programs

This case study describes how the Midwest Energy Efficiency Alliance (MEEA) partnered with gas and electric utilities in Iowa to establish the Iowa residential heating, ventilation, and air conditioning System Adjustment and Verified Efficiency (HVAC SAVE) program, taking it to scale improving the performance and energy efficiency of HVAC systems, growing businesses, and gaining consumer trust.

Federal efficiency standards, installation practic↗