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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 1,081 records · Page 60
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Multi-analytical approach reveals potential microbial indicators in soil for sugarcane model systems

This study focused on the effects of organic and inorganic amendments and straw retention on the microbial biomass (MB) and taxonomic groups of bacteria in sugarcane-cultivated soils in a greenhouse mesocosm experiment monitored for gas emissions and chemical factors. The experiment consisted of combinations of synthetic nitrogen (N), vinasse (V; a liquid waste from ethanol production), and sugarcane-straw blankets. Increases in CO 2 -C and N 2 O-N emissions were identified shortly after the addition of both N and V to the soils, thus increasing MB nitrogen (MB-N) and decreasing MB carbon (MB-C) in the N+V-amended soils and altering soil chemical factors that were correlated with the MB. Across 57 soil metagenomic datasets, Actinobacteria (31.5%), Planctomycetes (12.3%), Deltaproteobacteria (12.3%), Alphaproteobacteria (12.0%) and Betaproteobacteria (11.1%) were the most dominant bacterial groups during the experiment. Differences in relative abundance of metagenomic sequences were mainly revealed for Acidobacteria , Actinobacteria , Gammaproteobacteria and Verrucomicrobia with regard to N+V fertilization and straw retention. Differential abundances in bacterial groups were confirmed using 16S rRNA gene-targeted phylum-specific primers for real-time PCR analysis in all soil samples, whose results were in accordance with sequence data, except for Gammaproteobacteria . Actinobacteria were more responsive to straw retention with Rubrobacterales , Bifidobacteriales and Actinomycetales related to the chemical factors of N+V-amended soils. Acidobacteria subgroup 7 and Opitutae , a verrucomicrobial class, were related to the chemical factors of soils without straw retention as a surface blanket. Taken together, the results showed that MB-C and MB-N responded to changes in soil chemical factors and CO 2 -C and N 2 O-N emissions, especially for N+V-amended soils. The results also indicated that several taxonomic groups of bacteria, such as Acidobacteria , Actinobacteria and Verrucomicrobia , and their subgroups acted as early-warning indicators of N+V amendments and straw retention in sugarcane-cultivated soils, which can alter the soil chemical factors.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

QUIC: A Fast-Running High-Resolution 3D Building-Aware Urban Transport and Dispersion Modeling System

Transport and dispersion of airborne contaminants in urban environments is extremely complicated. Buildings alter the flow fields and deflect the wind, causing updrafts and downdrafts, channeling between buildings, areas of calm winds adjacent to strong winds, and horizontally and vertically rotating-eddies between buildings, at street corners, and other places within the urban canopy. High concentrations of fine particulate matter or carbon monoxide over short time periods can result from vehicle emissions that become trapped between tall buildings in urban areas. Toxic industrial chemicals are often transported via railcar and trucks near or through cities and stored among buildings and other structures at industrial and manufacturing sites that are sometimes found in or near inhabited locations. In addition to accidental releases, there is also concern of pre-meditated chemical, biological, and radiological attacks in cities.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Online stress corrosion crack and fatigue usages factor monitoring and prognostics in light water reactor components: Probabilistic modeling, system identification and data fusion based big data analytics approach

Nuclear reactors in the United States account for roughly 20% of the nation's total electric energy generation, and maintaining their safety in regards to key component structural integrity is critical not only for long term use of such plants but also for the safety of personnel and the public living around the plant. Early detection of damage signature such as of stress corrosion cracking, thermal-mechanical loading related material degradation in safety-critical components is a necessary requirement for long-term and safe operation of nuclear power plant systems.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2015

Final report for DOE Award # DE- SC0010039*: Carbon dynamics of forest recovery under a changing climate: Forcings, feedbacks, and implications for earth system modeling

To advance understanding of C dynamics of forests globally, we compiled a new database, the Forest C database (ForC-db), which contains data on ground-based measurements of ecosystem-level C stocks and annual fluxes along with disturbance history. This database currently contains 18,791 records from 2009 sites, making it the largest and most comprehensive database of C stocks and flows in forest ecosystems globally. The tropical component of the database will be published in conjunction with a manuscript that is currently under review (Anderson-Teixeira et al., in review). Database development continues, and we hope to maintain a dynamic instance of the entire (global) database.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Final Technical Report. Supporting carbon cycle and earth systems modeling with measurements and analysis from the Howland AmeriFlux Site

This report provides and overview of the work carried out and lists the products produced under the terms of agreement SC0005578 with the USDA Forest Service. This relates to scientific investigation of the carbon cycle at the Howland Forest AmeriFlux site located in central Maine, USDA. The overall goal of this work was to understand the various (and interacting) impacts of a changing climate on carbon cycling at the Howland AmeriFlux site, representative of an important component of the North American boreal forest.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Collaborative Project: Improving the Representation of Coastal and Estuarine Processes in Earth System Models

This project aimed to improve long term global climate simulations by resolving and enhancing the representation of the processes involved in the cycling of freshwater through estuaries and coastal regions. This was a collaborative multi-institution project consisting of physical oceanographers, climate model developers, and computational scientists. It specifically targeted the DOE objectives of advancing simulation and predictive capability of climate models through improvements in resolution and physical process representation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Final Technical Report for Department of Energy Award DE-SC0010857, “Towards parameterization of root-rock hydrologic interactions in the Earth System Model”

The goal of the project is to understand how plants survive droughts, as the decimation of transpiration could shift the surface energy balance from latent heat to sensible heat, leading to warming of the lower atmosphere and amplification of drought. The hypothesis we investigated is that there is a store of moisture in the weathered bedrock below the organic soil mantle, so that plants that have roots deep enough to access this moisture reservoir could survive drought. We developed a new stochastic parameterization of hydraulic conductivity that introduces heterogeneity into the traditional formulation and captures the preferential flow through the weathered bedrock (Vrettas and Fung, 2015). With the new parameterization in the Richards equation, we succeeded in reproducing the fluctuations of the water table in seven well locations over six years. We also and carried out a series of model experiments that explore how subsurface properties impact evapotranspiration (ET) in a Mediterranean climate where a significant portion of ET is observed to take place in the dry and sunny summer when the precipitation is insufficient to meet the demand. Our results show that hydraulic redistribution is important for sustaining ET in the dry seasons when the vertical gradient in water potential is large. The results highlight the importance of lithology, species composition and root function for ET, especially under dry conditions.

58 GEOSCIENCES↗
DOE OSTI2016

The Genetics of Biofuel Traits in Panicum Grasses: Developing a Model System with Diploid Panicum Hallii

Our DOE funded project focused on characterizing natural variation in C4 perennial grasses including switchgrass (Panicum virgatum) and Hall’s panicgrass (Panicum hallii). The main theme of our project was to better understand traits linked with plant performance and that impact the utility of plant biomass as a biofuel feedstock. In addition, our project developed tools and resources for studying genetic variation in Panicum hallii. Our project successfully screened both Panicum virgatum and Panicum hallii diverse natural collections for a host of phenotypes, developed genetic mapping populations for both species, completed genetic mapping for biofuel related traits, and helped in the development of genomic resources of Panicum hallii. Together, these studies have improved our understanding of the role of genetic and environmental factors in impacting plant performance. This information, along with new tools, will help foster the improvement of perennial grasses for feedstock applications.

09 BIOMASS FUELS↗