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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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5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on NaGe by Materials Project

NaGe crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent Na sites. In the first Na site, Na is bonded in a 6-coordinate geometry to six Ge atoms. There are a spread of Na–Ge bond distances ranging from 3.01–3.34 Å. In the second Na site, Na is bonded in a 5-coordinate geometry to six Ge atoms. There are a spread of Na–Ge bond distances ranging from 3.03–3.51 Å. In the third Na site, Na is bonded in a 5-coordinate geometry to five Ge atoms. There are a spread of Na–Ge bond distances ranging from 2.96–3.32 Å. In the fourth Na site, Na is bonded in a 4-coordinate geometry to five Ge atoms. There are a spread of Na–Ge bond distances ranging from 2.94–3.47 Å. There are four inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six Na and three Ge atoms. There are a spread of Ge–Ge bond distances ranging from 2.58–2.64 Å. In the second Ge site, Ge is bonded in a 8-coordinate geometry to five Na and three Ge atoms. There are one shorter (2.59 Å) and one longer (2.62 Å) Ge–Ge bond lengths. In the third Ge site, Ge is bonded in a 5-coordinate geometry to five Na and three Ge atoms. The Ge–Ge bond length is 2.58 Å. In the fourth Ge site, Ge is bonded in a 9-coordinate geometry to six Na and three Ge atoms.

36 MATERIALS SCIENCE↗
NASA NTRS2014

The Affect of the Space Environment on the Survival of Halorubrum Chaoviator and Synechococcus (Nageli): Data from the Space Experiment OSMO on EXPOSE-R

We have shown using ESA's Biopan facility flown in Earth orbit that when exposed to the space environment for 2 weeks the survival rate of Synechococcus (Nageli), a halophilic cyanobacterium isolated from the evaporitic gypsum-halite crusts that form along the marine intertidal, and Halorubrum chaoviator a member of the Halobacteriaceae isolated from an evaporitic NaCl crystal obtained from a salt evaporation pond, were higher than all other test organisms except Bacillus spores. These results led to the EXPOSE-R mission to extend and refine these experiments as part of the experimental package for the external platform space exposure facility on the ISS. The experiment was flown in February 2009 and the organisms were exposed to low-Earth orbit for nearly 2 years. Samples were either exposed to solar ultraviolet (UV)-radiation (lambda is greater than 110 nm or lambda is greater than 200 nm, cosmic radiation (dosage range 225-320 mGy), or kept in darkness shielded from solar UV-radiation. Half of each of the UV-radiation exposed samples and dark samples were exposed to space vacuum and half kept at 105 pascals in argon. Duplicate samples were kept in the laboratory to serve as unexposed controls. Ground simulation control experiments were also performed. After retrieval, organism viability was tested using Molecular Probes Live-Dead Bac-Lite stain and by their reproduction capability. Samples kept in the dark, but exposed to space vacuum had a 90 +/- 5% survival rate compared to the ground controls. Samples exposed to full UV-radiation for over a year were bleached and although results from Molecular Probes Live-Dead stain suggested approximately 10% survival, the data indicate that no survival was detected using cell growth and division using the most probable number method. Those samples exposed to attenuated UV-radiation exhibited limited survival. Results from of this study are relevant to understanding adaptation and evolution of life, the future of life beyond earth, the potential for interplanetary transfer of viable microbes via meteorites and dust particles as well as spacecraft, and the physiology of halophiles.

space flight↗
NASA NTRS1994

Metabolic activity of microorganisms in evaporites

Crystalline salt is generally considered so hostile to most forms of life that it has been used for centuries as a preservative. Here, we present evidence that prokaryotes inhabiting a natural evaporite crust of halite and gypsum are metabolically active while inside the evaporite for at least 10 months. In situ measurements demonstrated that some of these "endoevaporitic" microorganisms (probably the cyanobacterium Synechococcus Nageli) fixed carbon and nitrogen. Denitrification was not observed. Our results quantified the slow microbial activity that can occur in salt crystals. Implications of this study include the possibility that microorganisms found in ancient evaporite deposits may have been part of an evaporite community.

NASA Discipline Exobiology↗
DOE OSTI2022

Best practice reporting guideline for building stock energy models

Buildings are responsible for 38% of global greenhouse gas (GHG) emissions and, therefore, pathways to reduce their impact are crucial to achieve climate targets. Building stock energy models (BSEMs) have long been used as a tool to assess the current and future energy demand and environmental impact of building stocks. BSEMs have become more and more complex and are often tailored to case-specific datasets, which results in a high degree of heterogeneity among models. This heterogeneity, together with a lack of consistency in the reporting hinders the understanding of these models and, thereby, an accurate interpretation and comparison of results. In this paper we present a reporting guideline in order to improve reporting practices of BSEMs. The guideline was developed by experts as part of the IEA's Annex 70 and builds upon reporting guidelines from other fields. It consists of five topics (Overview, Model Components, Input and Output, Quality Assurance and Additional Information), which are further subdivided into subtopics. We explain which model aspects should be described in each subtopic, and provide illustrative examples on how to apply the guideline. In closing, the reporting guideline is consistent with the model classification framework and online model registry also developed in the Annex.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Challenges and Lessons Learned in Applying Sensitivity Analysis to Building Stock Energy Models

Uncertainty Analysis (UA) and Sensitivity Analysis (SA) offer essential tools to determine the limits of inference of a model and explore the factors which have the most effect on the model outputs. However, despite a well established body of work applying UA and SA to models of individual buildings, a review of the literature relating to energy models for larger groups of buildings undertaken by Fennell et al. (2019) highlighted very limited application at larger scales. This contribution describes the efforts undertaken by a group of research teams in the context of IEA-EBC Annex 70 working with a diverse set of Building Stock Models (BSMs) to apply global sensitivity analysis methods and compare their results. Since BSMs are a class of model defined by their output and coverage rather than their structure and inputs, they represent a diverse set of modelling approaches. Key challenges for the application of SA are identified and explored, including the influence of model form, input data types and model outputs. This study combines results from 7 different modelling teams, each using different models across a range of urban areas to explore these challenges and begin the process of developing standardised workflows for SA of BSMs.

ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION↗