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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Application of Colorimetric Solid Phase Extraction (C-SPE) to Monitoring Nickel(II) and Lead(II) in Spacecraft Water Supplies

Archived water samples collected on the International Space Station (ISS) and returned to Earth for analysis have, in a few instances, contained trace levels of heavy metals. Building on our previous advances using Colorimetric Solid Phase Extraction (C-SPE) as a biocide monitoring technique, we are devising methods for the low level monitoring of nickel(II), lead(II) and other heavy metals. C-SPE is a sorption-spectrophotometric platform based on the extraction of analytes onto a membrane impregnated with a colorimetric reagent that are then quantified on the surface of the membrane using a diffuse reflectance spectrophotometer. Along these lines, we have determined nickel(II) via complexation with dimethylglyoxime (DMG) and begun to examine the analysis of lead(II) by its reaction with 2,5- dimercapto-1,3,4-thiadiazole (DMTD) and 4-(2- pyridylazo)-resorcinol (PAR). These developments are also extending a new variant of C-SPE in which immobilized reagents are being incorporated into this methodology in order to optimize sample reaction conditions and to introduce the colorimetric reagent. This paper describes the status of our development of these two new methods.

Diaz, Neil C.↗
NASA NTRS2006

Haughton-Mars Project Expedition 2005: Interplanetary Supply Chain Management & Logistics Architectures

The 2005 expedition to the Haughton-Mars Project (HMP) research station on Devon Island was part of a NASA-funded project on Space Logistics. A team of nine researchers from MIT went to the Canadian Arctic to participate in the annual HMP field campaign from July 8 to August 12, 2005. We investigated the applicability of the HMP research station as an analogue for planetary macro- and micro-logistics to the Moon and Mars, and began collecting data for modeling purposes. We also tested new technologies and procedures to enhance the ability of humans and robots to jointly explore remote environments. The expedition had four main objectives. We briefly summarize our key findings in each of these areas.

deWeck, Olivier↗
NASA NTRS2008

Civil Service Workforce Market Supply and the Effect on the Cost Estimating Relationships (CERs) that may effect the Productivity Factors for Future NASA Missions

The upcoming retirement of the Baby Boomers on the horizon will leave a performance gap between younger generation (the future NASA decision makers) and the gray beards. This paper will reflect on the average age of workforce across NASA Centers, the Aerospace Industry and other Government Agencies, like DoD. This papers will dig into Productivity and Realization Factors and how they get applied to bimonthly (payroll data) for true FTE calculations that could be used at each of the NASA Centers and other business systems that are on the forefront in being implemented. This paper offers some comparative costs solutions, from simple - full time equivalent (FTE) cost estimating relationships CERs, to complex - CERs for monthly time-phasing activities for small research projects that start and get completed within a government fiscal year. This paper will present the results of a parametric study investigating the cost-effectiveness of different alternatives performance based cost estimating relationships (CERs) and how they get applied into the Center s forward pricing rate proposals (FPRP). True CERs based on the relationship of a younger aged workforce will have some effects on labor rates used in both commercial cost models and internal home-grown cost models which may impact the productivity factors for future NASA missions.

Sterk, Steve↗
NASA NTRS2008

Civil Service Workforce Market Supply and the Effect on Cost Estimating Relationship (CERS) that May Effect the Productivity Factors for Future NASA Missions

The upcoming retirement of the Baby Boomers will leave a workforce age gap between the younger generation (the future NASA decision makers) and the gray beards. This paper will reflect on the average age of the workforce across NASA Centers, the Aerospace Industry and other Government Agencies, like DoD. This paper will dig into Productivity and Realization Factors and how they get applied to bi-monthly (payroll) data for true full-time equivalent (FTE) calculations that could be used at each of the NASA Centers and other business systems that are on the forefront in being implemented. This paper offers some comparative costs analysis/solutions, from simple FTE cost-estimating relationships (CERs) versus CERs for monthly time-phasing activities for small research projects that start and get completed within a government fiscal year. This paper will present the results of a parametric study investigating the cost-effectiveness of alternative performance-based CERs and how they get applied into the Center's forward pricing rate proposals (FPRP). True CERs based on the relationship of a younger aged workforce will have some effects on labor rates used in both commercial cost models and other internal home-grown cost models which may impact the productivity factors for future NASA missions.

Sterk, Steve↗
NASA NTRS2006

Reliability Block Diagram (RBD) Analysis of NASA Dryden Flight Research Center (DFRC) Flight Termination System and Power Supply

In order to perform public risk analyses for vehicles containing Flight Termination Systems (FTS), it is necessary for the analyst to know the reliability of each of the components of the FTS. These systems are typically divided into two segments; a transmitter system and associated equipment, typically in a ground station or on a support aircraft, and a receiver system and associated equipment on the target vehicle. This analysis attempts to analyze the reliability of the NASA DFRC flight termination system ground transmitter segment for use in the larger risk analysis and to compare the results against two established Department of Defense availability standards for such equipment.

Morehouse, Dennis V.↗
NASA NTRS2011

NASA Goddard Space Flight Center Supply Chain Management Program

This slide presentation reviews the working of the Supplier Assessment Program at NASA Goddard Space Flight Center. The program supports many GSFC projects to ensure suppliers are aware of and are following the contractual requirements, to provide an independent assessment of the suppliers' processes, and provide suppliers' safety and mission assurance organizations information to make the changes within their organization.

Kelly, Michael P.↗
NASA NTRS2011

Fast-responding short circuit protection system with self-reset for use in circuit supplied by DC power

A short circuit protection system includes an inductor, a switch, a voltage sensing circuit, and a controller. The switch and inductor are electrically coupled to be in series with one another. A voltage sensing circuit is coupled across the switch and the inductor. A controller, coupled to the voltage sensing circuit and the switch, opens the switch when a voltage at the output terminal of the inductor transitions from above a threshold voltage to below the threshold voltage. The controller closes the switch when the voltage at the output terminal of the inductor transitions from below the threshold voltage to above the threshold voltage.

Burns, Bradley M.↗
NASA NTRS2011

Retrospective Analog Year Analyses Using NASA Satellite Data to Improve USDA's World Agricultural Supply and Demand Estimates

The USDA World Agricultural Outlook Board (WAOB) is responsible for monitoring weather and climate impacts on domestic and foreign crop development. One of WAOB's primary goals is to determine the net cumulative effect of weather and climate anomalies on final crop yields. To this end, a broad array of information is consulted, including maps, charts, and time series of recent weather, climate, and crop observations; numerical output from weather and crop models; and reports from the press, USDA attach s, and foreign governments. The resulting agricultural weather assessments are published in the Weekly Weather and Crop Bulletin, to keep farmers, policy makers, and commercial agricultural interests informed of weather and climate impacts on agriculture. Because both the amount and timing of precipitation significantly affect crop yields, WAOB often uses precipitation time series to identify growing seasons with similar weather patterns and help estimate crop yields for the current growing season, based on observed yields in analog years. Historically, these analog years are visually identified; however, the qualitative nature of this method sometimes precludes the definitive identification of the best analog year. Thus, one goal of this study is to derive a more rigorous, statistical approach for identifying analog years, based on a modified coefficient of determination, termed the analog index (AI). A second goal is to compare the performance of AI for time series derived from surface-based observations vs. satellite-based measurements (NASA TRMM and other data).

Teng, William↗
NASA NTRS2017

How Accurately Do Maize Crop Models Simulate the Interactions of Atmospheric CO2 Concentration Levels With Limited Water Supply on Water Use and Yield?

This study assesses the ability of 21 crop models to capture the impact of elevated CO2 concentration [CO2] on maize yield and water use as measured in a 2-year Free Air Carbon dioxide Enrichment experiment conducted at the Thunen Institute in Braunschweig, Germany (Manderscheid et al. 2014). Data for ambient [CO2] and irrigated treatments were provided to the 21 models for calibrating plant traits, including weather, soil and management data as well as yield, grain number, above ground biomass, leaf area index, nitrogen concentration in biomass and grain, water use and soil water content. Models differed in their representation of carbon assimilation and evapotranspiration processes. The models reproduced the absence of yield response to elevated [CO2] under well-watered conditions, as well as the impact of water deficit at ambient [CO2], with 50 percent of models within a range of plus/minus 1 Mg ha(exp. -1) around the mean. The bias of the median of the 21 models was less than 1 Mg ha(exp. -1). However under water deficit in one of the two years, the models captured only 30 percent of the exceptionally high [CO2] enhancement on yield observed. Furthermore the ensemble of models was unable to simulate the very low soil water content at anthesis and the increase of soil water and grain number brought about by the elevated [CO2] under dry conditions. Overall, we found models with explicit stomatal control on transpiration tended to perform better. Our results highlight the need for model improvement with respect to simulating transpirational water use and its impact on water status during the kernel-set phase.

grain number↗
NASA NTRS2019

Supplying a Pharmacy for NASA Exploration Spaceflight: Challenges and Current Understanding

In order to maintain crew health and performance during long-duration spaceflight outside of low-Earth orbit, NASA and its international partners must be capable of providing a safe and effective pharmacy. Given few directed studies of pharmaceuticals in the space environment, it is difficult to characterize pharmaceutical effectiveness or stability during spaceflight; this in turn makes it challenging to select an appropriate formulary for exploration. Here we present the current state of literature regarding pharmaceutical stability, metabolism, and effectiveness during spaceflight. In particular, we have attempted to highlight the gaps in current knowledge and the difficulties in translating terrestrial-based drug studies to a meaningful interpretation of drug stability, safety, and effectiveness in space. We hope to identify high-yield opportunities for future research that might better define and mitigate pharmaceutical risk for exploration missions.

Rebecca S Blue↗