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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 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Seasonal Trends of Soiling on Photovoltaic Systems

This work investigates the seasonal variability of photovoltaic soiling losses over a 12-month period for 15 soiling stations deployed in the USA. We present a new parameter able to rank the sites according to the cumulative losses occurring over 3- and 6- month periods. The relations between soiling losses and particulate matter are briefly discussed, as well. Moving from long-term to shorter-term data increases the complexity of the analysis: monthly correlations are found to have lower accuracy than the longer-term ones presented in the literature.

14 SOLAR ENERGY↗
DOE OSTI2021

Clear Sky Irradiance Year-to-Year Variations and Trends

Solar radiation data for seven SURFRAD stations for the period 1996-2018 show an increase in irradiance under clear skies over the period, but the increase was not constant and shorter periods may have even experienced decreases in irradiance. A popular implementation of a clear sky model provided modeled irradiances for comparison with the SURFRAD data under conditions screened for clear skies. The use of the clear sky model, which did not consider year-to-year variances in atmospheric turbidity, was found problematic for resolving small changes in irradiance important for determining PV system degradation over three or five years, but less problematic for a period of ten years.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2024

Trends and Heterogeneity in Electric Vehicle Economics: A French Case Study

The total cost of ownership of electric vehicles depends on both the behavior and economic context of the driver as well as the level of government support offered for electrified vehicles. In this work, we study both of these effects as they shift private vehicle costs and emissions benefits, focused on a case study of the faculty and staff commuters to the Cite Scientifique campus of the University of Lille. The modeling approach considers the net costs and emissions from switching each driver from an internal combustion engine vehicle to three electrified options: a hybrid electric, a plug-in hybrid, and a pure battery electric. Increasing government support or technology-induced cost declines of electric vehicles both improve the economics of electrified options and shift more drivers towards battery electrics as the preferred alternative to thermal vehicles.

ADVANCED PROPULSION SYSTEMS,ENERGY PLANNING, POLIC↗
DOE OSTI2022

Current trends in waste valorization

This paper presents the scientific breakthroughs made in bioprocess engineering and microbial biotechnology for the conversion of wastes into products with added value and/or biofuels. The significant results obtained in the emerging fields of hybrid electrosynthesis, the role of enzymes in the degradation of plastics, polyhydroxyalkanoate and 5-aminolevulinic acid production, fermentation technology and the application of molecular engineering tools to bioprocess technology are highlighted.

09 BIOMASS FUELS↗
DOE OSTI2024

Economic and environmental bottlenecks in the industrial‐scale production of lipid‐derived biofuels from oleaginous yeasts: A review of the current trends and future prospects

Abstract Concerns about climate change and the reliance on fossil fuel reserves have motivated researchers to identify new renewable sources of energy. Biomass holds the potential to replace fossil‐derived products with biofuels and bio‐based chemicals. Plant‐derived lipids are promising sources of biofuels; however, the production of plant oil often leads to the release of massive amounts of carbon dioxide due to deforestation and land‐use change. The production of biofuels via plant oils (such as soybean) also competes with food production and in turn, impacts biodiversity. To mitigate these issues, the production of lipids from oleaginous yeasts could be an excellent alternative by incorporating these microbes into biorefineries utilizing agricultural or forest residues. Eventually, these microbial lipids could be potential sources for producing lipid‐derived biofuels. However, the current conventional methods for the production and recovery of lipids from oleaginous microbes suffer from economic and ecological challenges that affect its industrial‐scale expansion. This review highlights the major economic and environmental bottlenecks for the production of lipid‐derived biofuels from oleaginous yeasts. It also provides perspectives on the strategies that could be adapted on economic and ecological fronts to assist the expansion of the production of microbial lipid‐derived biofuels at an industrial scale.

Agriculture↗
DOE OSTI2017

Review Article: Case studies in future trends of computational and experimental nanomechanics

With rapidly increasing numbers of studies of new and exotic material uses for perovskites and quasicrystals, these demand newer instrumentation and simulation developments to resolve the revealed complexities. One such set of observational mechanics at the nanoscale is presented here for somewhat simpler material systems. The expectation is that these approaches will assist those materials scientists and physicists needing to verify atomistic potentials appropriate to the nanomechanical understanding of increasingly complex solids. The five following segments from nine University, National and Industrial Laboratories both review and forecast where some of the important approaches will allow a confirming of how in situ mechanics and nanometric visualization might unravel complex phenomena. These address two-dimensional structures, temporal models for the nanoscale, atomistic and multiscale friction fundamentals, nanoparticle surfaces and interfaces and nanomechanical fracture measurements, all coupled to in situ observational techniques. Rapid future advances in the applicability of such materials science solutions appear guaranteed.

36 MATERIALS SCIENCE↗
DOE OSTI2016

SU-F-T-458: Tracking Trends of TG-142 Parameters Via Analysis of Data Recorded by 2D Chamber Array

Purpose: With increasing QA demands of medical physicists in clinical radiation oncology, the need for an effective method of tracking clinical data has become paramount. A tool was produced which scans through data automatically recorded by a 2D chamber array and extracts relevant information recommended by TG-142. Using this extracted information a timely and comprehensive analysis of QA parameters can be easily performed enabling efficient monthly checks on multiple linear accelerators simultaneously. Methods: A PTW STARCHECK chamber array was used to record several months of beam outputs from two Varian 2100 series linear accelerators and a Varian NovalisTx−. In conjunction with the chamber array, a beam quality phantom was used to simultaneously to determine beam quality. A minimalist GUI was created in MatLab that allows a user to set the file path of the data for each modality to be analyzed. These file paths are recorded to a MatLab structure and then subsequently accessed by a script written in Python (version 3.5.1) which then extracts values required to perform monthly checks as outlined by recommendations from TG-142. The script incorporates calculations to determine if the values recorded by the chamber array fall within an acceptable threshold. Results: Values obtained by the script are written to a spreadsheet where results can be easily viewed and annotated with a “pass” or “fail” and saved for further analysis. In addition to creating a new scheme for reviewing monthly checks, this application allows for able to succinctly store data for follow up analysis. Conclusion: By utilizing this tool, parameters recommended by TG-142 for multiple linear accelerators can be rapidly obtained and analyzed which can be used for evaluation of monthly checks.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2015

The dominant role of semi-arid ecosystems in the trend and variability of the land CO 2 sink

The difference is found at the margins The terrestrial biosphere absorbs about a quarter of all anthropogenic carbon dioxide emissions, but the amount that they take up varies from year to year. Why? Combining models and observations, Ahlström et al. found that marginal ecosystems—semiarid savannas and low-latitude shrublands—are responsible for most of the variability. Biological productivity in these semiarid regions is water-limited and strongly associated with variations in precipitation, unlike wetter tropical areas. Understanding carbon uptake by these marginal lands may help to improve predictions of variations in the global carbon cycle. Science , this issue p. 895

Ahlström, Anders↗
DOE OSTI2013

Modern trends in methods of charged particle identification at high energies

The survey is devoted to methods of charged particle identification at high energies that are based on measurements of the angle of Cherenkov radiation (ring imaging Cherenkov counters — RICH), of time of flight (TOF) and propagation (TOP), and of ionization energy loss (dE / dx ). As an example, some operating spectrometers are considered (LHCb, ALICE, COMPASS, Belle, and BaBar) together with proposed ones (Belle-2 and PANDA) in which new achievements of recent years are introduced.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Relativistic nuclear theory—nucleons and mesons: origin, current status, and trends

The nuclear shell model (NSM) is a fundamental model of nuclear theory. At the initial stage, the NSM was developed on the basis of the Schrödinger equation, in particular because it was not clear which Dirac matrices should be associated with various components of the (relativistic) shell model potential. In the early 1970s, the relativistic version of the NSM with meson fields as its main components was developed on the basis of the Dirac equation. The relativistic nuclear shell model (RNSM) includes meson fields with different space–time transformation properties (scalar, four-vector, etc.) that determine the behavior of the (corresponding) meson fields under Lorentz transformations. This fact directly indicates that nuclear theory should be relativistic and based on the Dirac equation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Trends in Reverse-Current Change in Tunnel MIS Diodes with Calcium Fluoride on Si(111) Upon the Formation of an Extra Oxide Layer

The currents flowing in metal–CaF{sub 2}–n-Si and metal–SiO{sub 2}–CaF{sub 2}–n-Si structures with the same (about 1.5 nm) fluoride thickness are compared in the reverse-bias mode. It is revealed that the current in the case of a two-layer dielectric can be notably higher within a certain voltage range. Such unexpected behavior is associated with the coexistence of both electron and hole components of the current as well as with the configuration of the SiO{sub 2}–CaF{sub 2} barrier through which tunneling occurs. The results of measurements and explanatory simulation data are presented.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗