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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Direct observation of multiple rotational stacking faults coexisting in freestanding bilayer MoS 2

Electronic properties of two-dimensional (2D) MoS 2 semiconductors can be modulated by introducing specific defects. One important type of defect in 2D layered materials is known as rotational stacking fault (RSF), but the coexistence of multiple RSFs with different rotational angles was not directly observed in freestanding 2D MoS 2 before. In this report, we demonstrate the coexistence of three RSFs with three different rotational angles in a freestanding bilayer MoS 2 sheet as directly observed using an aberration-corrected transmission electron microscope (TEM). Our analyses show that these RSFs originate from cracks and dislocations within the bilayer MoS 2 . First-principles calculations indicate that RSFs with different rotational angles change the electronic structures of bilayer MoS 2 and produce two new symmetries in their bandgaps and offset crystal momentums. Therefore, employing RSFs and their coexistence is a promising route in defect engineering of MoS 2 to fabricate suitable devices for electronics, optoelectronics, and energy conversion.

Science & Technology - Other Topics↗
DOE OSTI2011

Analysis of Interstitial Elements in Niobium with Secondary Ion Mass Spectrometry (SIMS)

Superconducting Radio Frequency (SRF) cavities provide enhanced efficiency and reduced energy utilization in present day particle accelerators. Niobium (Nb) is the material of choice for these cavities due to its high critical temperature and critical magnetic field. In order to understand why certain treatments, especially a low temperature bake, improve performance, it is important to study Nb surface characteristics and identify elemental contamination that can affect the performance of the cavity. H, C, O, and N are of interest because they are interstitial impurities in Nb. In earlier work, SIMS analysis using a CAMECA IMS-6F with Cs{sup +} primary beam showed that C and N were probably not significant factors impacting performance but there was a very high level of H in the Nb. Ion implants of C, N, O, and D into Nb provided quantification of C, N, O and indicated that D is very mobile in the Nb. Further analyses showed that heat treated Nb has lower levels of surface H than non heat treated Nb and subsequent removal of surface oxide by etching causes intake of H in a heat treated Nb sample. This result helps confirm the role of surface oxide as a hydrogen barrier. To further understand the oxide, Nb samples were anodized to obtain a thicker surface oxide and H and D were implanted into this oxide to check for the appearance of implant peaks. SIMS depth profile analyses were carried out and confirmed the presence of the implant shape for these elements in the oxide. Relative Sensitivity Factor (RSFs) could then be calculated for quantification of H in the oxide. Since the Nb matrix signal showed little change from the oxide to the substrate, the same RSF was used to estimate the H concentration in the Nb at 2x10{sup 22} atoms/cm{sup 3}(approximately 40% mole fraction H).

36 MATERIALS SCIENCE↗
DOE OSTI2014

Correlation between upconversion photoluminescence and dielectric response in Ba-substituted (Sr{sub 1−x}Ba{sub x}){sub 4}(La{sub 0.85}Ho{sub 0.025}Yb{sub 0.125}){sub 2}Ti{sub 4}Nb{sub 6}O{sub 30}

The filled tetragonal tungsten bronze (Sr{sub 1−x}Ba{sub x}){sub 4}(La{sub 0.85}Ho{sub 0.025}Yb{sub 0.125}){sub 2}Ti{sub 4}Nb{sub 6}O{sub 30} (SBLTNx: Ho-Yb) ceramics with different Ba substitution levels (x) are prepared. The upconversion photoluminescence (UC-PL) and dielectric permittivity are investigated. The substitution of Sr{sup 2+} ions at the A{sub 2}-sites by larger Ba{sup 2+} ions results in substantial variation of the UC-PL intensity as a function of substitution level x. Furthermore, the dielectric response to the substitution of Sr{sup 2+} by Ba{sup 2+} suggests a close correlation between the UC-PL intensity and dielectric permittivity. The origin for this correlation is discussed based on the random stress field (RSF) model.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Early-type galaxies at intermediate redshift observed with Hubble space telescope WFC3: perspectives on recent star formation

We present an analysis of the stellar populations of 102 visually selected early-type galaxies (ETGs) with spectroscopic redshifts (0.35 ≲ z ≲ 1.5) from observations in the Early Release Science program with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). We fit one- and two-component synthetic stellar models to the ETGs UV-optical-near-IR spectral energy distributions and find that a large fraction (∼40%) are likely to have experienced a minor (f{sub YC} ≲ 10% of stellar mass) burst of recent (t{sub YC} ≲ 1 Gyr) star formation. The measured age and mass fraction of the young stellar populations do not strongly trend with measurements of galaxy morphology. We note that massive (M > 10{sup 10.5} M {sub ☉}) recent star-forming ETGs appear to have larger sizes. Furthermore, high-mass, quiescent ETGs identified with likely companions populate a distinct region in the size-mass parameter space, in comparison with the distribution of massive ETGs with evidence of recent star formation (RSF). We conclude that both mechanisms of quenching star formation in disk-like ETGs and (gas-rich, minor) merger activity contribute to the formation of young stars and the size-mass evolution of intermediate redshift ETGs. The number of ETGs for which we have both HST WFC3 panchromatic (especially UV) imaging and spectroscopically confirmed redshifts is relatively small, therefore, a conclusion about the relative roles of both of these mechanisms remains an open question.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Composition Quantification of SiGeSn Alloys Through Time-of-Flight Secondary Ion Mass Spectrometry: Calibration Methodologies and Validation With Atom Probe Tomography

Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a powerful technique for elemental compositional analysis and depth profiling of materials. However, it encounters the problem of matrix effects that hinder its application. In this work, we introduce a pioneering ToF-SIMS calibration method tailored for SixGeySnz ternary alloys. SixGe1-x and Ge1-zSnz binary alloys with known compositions are used as calibration reference samples. Through a systematic SIMS quantification study of SiGe and GeSn binary alloys, we unveil a linear correlation between secondary ion intensity ratio and composition ratio for both SiGe and GeSn binary alloys, effectively mitigating the matrix effects. Extracted relative sensitivity factor (RSF) value from SixGe1-x (0.07 < x < 0.83) and Ge1-zSnz (0.066 < z < 0.183) binary alloys are subsequently applied to those of SixGeySnz (0.011 < x < 0.113, 0.863 < y < 0.935 and 0.023 < z < 0.103) ternary alloys for elemental compositions quantification. These values are cross-checked by Atom Probe Tomography (APT) analysis, an indication of the great accuracy and reliability of as-developed ToF-SIMS calibration process. Furthermore, the proposed method and its reference sample selection strategy in this work provide a low-cost as well as simple-to-follow calibration route for SiGeSn composition analysis, thus driving the development of next-generation multifunctional SiGeSn-related semiconductor devices.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Quantitative imaging of trace B in Si and SiO{sub 2} using ToF-SIMS

Changes in the oxidation state of an element can result in significant changes in the ionization efficiency and hence signal intensity during secondary ion mass spectrometry (SIMS) analysis; this is referred to as the SIMS matrix effect [Secondary Ion Mass Spectrometry: A Practical Handbook for Depth Profiling and Bulk Impurity Analysis, edited by R. G. Wilson, F. A. Stevie, and C. W. Magee (Wiley, New York, 1990)]. The SIMS matrix effect complicates quantitative analysis. Quantification of SIMS data requires the determination of relative sensitivity factors (RSFs), which can be used to convert the as measured intensity into concentration units [Secondary Ion Mass Spectrometry: A Practical Handbook for Depth Profiling and Bulk Impurity Analysis, edited by R. G. Wilson, F. A. Stevie, and C. W. Magee (Wiley, New York, 1990)]. In this manuscript, the authors report both: RSFs which were determined for quantification of B in Si and SiO{sub 2} matrices using a dual beam time of flight secondary ion mass spectrometry (ToF-SIMS) instrument and the protocol they are using to provide quantitative ToF-SIMS images and line scan traces. The authors also compare RSF values that were determined using oxygen and Ar ion beams for erosion, discuss the problems that can be encountered when bulk calibration samples are used to determine RSFs, and remind the reader that errors in molecular details of the matrix (density, volume, etc.) that are used to convert from atoms/cm{sup 3} to other concentration units will propagate into errors in the determined concentrations.

42 ENGINEERING↗
DOE OSTI2016

SU-F-T-143: Implementation of a Correction-Based Output Model for a Compact Passively Scattered Proton Therapy System

Purpose: To commission and investigate the accuracy of an output (cGy/MU) prediction model for a compact passively scattered proton therapy system. Methods: A previously published output prediction model (Sahoo et al, Med Phys, 35, 5088–5097, 2008) was commissioned for our Mevion S250 proton therapy system. This model is a correction-based model that multiplies correction factors (d/MUwnc=ROFxSOBPF xRSFxSOBPOCFxOCRxFSFxISF). These factors accounted for changes in output due to options (12 large, 5 deep, and 7 small), modulation width M, range R, off-center, off-axis, field-size, and off-isocenter. In this study, the model was modified to ROFxSOBPFxRSFxOCRxFSFxISF-OCFxGACF by merging SOBPOCF and ISF for simplicity and introducing a gantry angle correction factor (GACF). To commission the model, outputs over 1,000 data points were taken at the time of the system commissioning. The output was predicted by interpolation (1D for SOBPF, FSF, and GACF; 2D for RSF and OCR) with inverse-square calculation (ISF-OCR). The outputs of 273 combinations of R and M covering total 24 options were measured to test the model. To minimize fluence perturbation, scattered dose from range compensator and patient was not considered. The percent differences between the predicted (P) and measured (M) outputs were calculated to test the prediction accuracy ([P-M]/Mx100%). Results: GACF was required because of up to 3.5% output variation dependence on the gantry angle. A 2D interpolation was required for OCR because the dose distribution was not radially symmetric especially for the deep options. The average percent differences were −0.03±0.98% (mean±SD) and the differences of all the measurements fell within ±3%. Conclusion: It is concluded that the model can be clinically used for the compact passively scattered proton therapy system. However, great care should be taken when the field-size is less than 5×5 cm{sup 2} where a direct output measurement is required due to substantial output change by irregular block shape.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Building Agent™ Software (BA) [SWRs 12-05 and 17-21]

Energy interfaces provide a new level of motivational information. Many studies have reported energy savings after dashboards for operators are installed, but these provide little actionable information to the occupant and the occupant cannot report individual comfort. The Building Agent™ (BA), in development at the National Renewable Energy Laboratory (NREL), provides an interface for the occupant to converse with the building control system and aims to actively engage and affect occupant behavior to achieve positive energy outcomes. Energy savings achieved via occupant behavioral changes could be as high as 25%, and could rival savings achieved by technological measures. For example, energy audits often show that more than 50% of the energy used in a building is consumed at night. Occupants leaving equipment and lighting on after they leave work is a large contributing factor. Similar savings opportunities have been identified when occupants were away from their desks 50% of the time, while most of their computers, lights, and other equipment remained powered on. Building Agent aims to create cohesion between building automation system (BAS) data, local measurements, and occupant feedback to provide visualizations, empowering occupants and building engineers to take diagnostic, proactive, energy-saving, and comfort-improving actions. The multilayer BA architecture consists of central server, measurement, and distributed application layers. The server layer aggregates global and localized measurements with occupant feedback to correlate perceived comfort with actual data throughout the building. The measurement layer complements BAS data with localized, environmental condition measurements at workstations. The application layer provides a bidirectional communications mechanism between the building and the occupants that accepts comfort feedback and provides energy performance information. The interface layer also uses three displays to influence building energy use: empathetic and personalized gauges, graphical data, and competitive rankings. Building Agent was implemented at NREL in the Research Support Facility (RSF), a LEED Platinum and Net Zero office building, which has received many awards. The constant feedback from occupants has enabled BA to better enhance the BAS data controls. Continued work is being done on BA to increase visualization of data and enhanced the user experience.

Long, Nicholas↗
DOE OSTI2012

Greater Sage-Grouse Habitat Use and Population Demographics at the Simpson Ridge Wind Resource Area, Carbon County, Wyoming

This study was conducted to obtain baseline data on use of the proposed Simpson Ridge Wind Resource Area (SRWRA) in Carbon County, Wyoming by greater sage-grouse. The first two study years were designed to determine pre-construction seasonally selected habitats and population-level vital rates (productivity and survival). The presence of an existing wind energy facility in the project area, the PacifiCorp Seven Mile Hill (SMH) project, allowed us to obtain some information on initial sage-grouse response to wind turbines the first two years following construction. To our knowledge these are the first quantitative data on sage-grouse response to an existing wind energy development. This report presents results of the first two study years (April 1, 2009 through March 30, 2011). This study was selected for continued funding by the National Wind Coordinating Collaborative Sage-Grouse Collaborative (NWCC-SGC) and has been ongoing since March 30, 2011. Future reports summarizing results of this research will be distributed through the NWCC-SGC. To investigate population trends through time, we determined the distribution and numbers of males using leks throughout the study area, which included a 4-mile radius buffer around the SRWRA. Over the 2-year study, 116 female greater sage-grouse were captured by spotlighting and use of hoop nets on roosts surrounding leks during the breeding period. Radio marked birds were located anywhere from twice a week to once a month, depending on season. All radio-locations were classified to season. We developed predictor variables used to predict success of fitness parameters and relative probability of habitat selection within the SRWRA and SMH study areas. Anthropogenic features included paved highways, overhead transmission lines, wind turbines and turbine access roads. Environmental variables included vegetation and topography features. Home ranges were estimated using a kernel density estimator. We developed resource selection functions (RSF) to estimate probability of selection within the SRWRA and SMH. Fourteen active greater sage-grouse leks were documented during lek surveys Mean lek size decreased from 37 in 2008 to 22 in 2010. Four leks located 0.61, 1.3, 1.4 and 2.5 km from the nearest wind turbine remained active throughout the study, but the total number of males counted on these four leks decreased from 162 the first year prior to construction (2008), to 97 in 2010. Similar lek declines were noted in regional leks not associated with wind energy development throughout Carbon County. We obtained 2,659 sage-grouse locations from radio-equipped females, which were used to map use of each project area by season. The sage-grouse populations within both study areas are relatively non-migratory, as radio-marked sage-grouse used similar areas during all annual life cycles. Potential impacts to sage-grouse from wind energy infrastructure are not well understood. The data rom this study provide insight into the early interactions of wind energy infrastructure and sage-grouse. Nest success and brood-rearing success were not statistically different between areas with and without wind energy development in the short-term. Nest success also was not influenced by anthropogenic features such as turbines in the short-term. Additionally, female survival was similar among both study areas, suggesting wind energy infrastructure was not impacting female survival in the short-term; however, further analysis is needed to identify habitats with different levels of risk to better understand the impact of wind energy development on survival. Nest and brood-rearing habitat selection were not influenced by turbines in the short-term; however, summer habitat selection occurred within habitats closer to wind turbines. Major roads were avoided in both study areas and during most of the seasons. The impact of transmission lines varied among study areas, suggesting other landscape features may be influencing selection. The data provided in this report are preliminary and are not meant to provide a basis for forming any conclusions regarding potential impacts of wind energy development on sage-grouse. Although the data collected during the initial phases of this study indicate that greater sage-grouse may continue to use habitats near wind-energy facilities, research conducted on greater sage-grouse response to oil and gas development has found population declines may not occur until 2-10 years after development. Therefore, long-term data from several geographic areas within the range of the sage-grouse will likely be required to adequately assess impacts of wind-energy development on greater sage-grouse.

17 WIND ENERGY↗
DOE OSTI2013

Compatibility Study for Plastic, Elastomeric, and Metallic Fueling Infrastructure Materials Exposed to Aggressive Formulations of Isobutanol-blended Gasoline

The Energy Independence and Security Act (EISA) of 2007 is an omnibus energy policy law designed to move the United States toward greater energy security and independence. A key provision of EISA is the Renewable Fuel Standard (RFS), which requires the nation to use 36 billion gallons per year (BGPY) of renewable fuel in vehicles by 2022. Ethanol is the most widely used renewable fuel, and increasing the allowable ethanol content from 10% to 15% is expected to push renewable fuel consumption to as much as 21 BGPY. Therefore, a large portion of the 36 billion gallon requirement can be met by increasing the ethanol content in gasoline to 15%. However, raising the ethanol content to 15%, by itself, will still not fully meet the RSF requirement, and concerns have been raised that this increase in ethanol may not be entirely compatible with current and legacy materials used in standard gasoline fueling systems. In the summer of 2008, the U.S. Department of Energy (DOE) recognized the need to assess the impact of intermediate blends of ethanol on the fueling infrastructure, specifically those systems located at the fueling station. A short time later (March 2009), Growth Energy (a coalition of ethanol producers and supporters) requested a waiver from the U.S. Environmental Protection Agency (EPA) to allow the use of 15% ethanol in gasoline. In 1981 the EPA approved a waiver (known as the OCTAMIX waiver) that allowed other alcohol types (such as methanol) to be blended with gasoline as long as the resulting fuel blend was substantially similar to gasoline. Another requirement is that the fuel oxygen content cannot exceed 3.7 wt %. Currently, this requirement limits ethanol in gasoline to 10 vol %. The corresponding oxygen equivalent for isobutanol is 16 vol %; therefore, isobutanol offers a pathway towards meeting the RFS requirement by allowing greater biofuel usage than can be achieved by ethanol alone. In fact, the United States has already hit the “blend wall” for ethanol, the point at which virtually all gasoline sold is E10 and no remaining market is left for ethanol, meaning that the country cannot substantially increase ethanol usage unless the EPA allows for higher levels of ethanol or until E85 use is expanded significantly. Butamax Advanced Biofuels, LLC has developed proprietary technologies to convert corn into isobutanol. Much of the infrastructure already existing at ethanol plants can be readily converted to produce isobutanol instead. The focus of this investigation was to compare the compatibility of fueling infrastructure materials (such as elastomers, plastics, and metals) to test fuels representing E10 and E15 and their corresponding oxygen equivalents with isobutanol (iBu16 and iBu24). Butamax sponsored a research project at Oak Ridge National Laboratory (ORNL) to perform empirical studies using aggressive fuel formulations representing 16 and 24% isobutanol. The results contained within this report include a solubility analysis for each material type and fuel formulation and empirical results for elastomers, plastics, and metals. Data obtained from the preceding ethanol compatibility studies on these materials are included for additional interpretation and summary.

Kass, Michael D.↗
DOE OSTI2014

Control Limits for Building Energy End Use Based on Engineering Judgment, Frequency Analysis, and Quantile Regression

Approaches are needed to continuously characterize the energy performance of commercial buildings to allow for (1) timely response to excess energy use by building operators; and (2) building occupants to develop energy awareness and to actively engage in reducing energy use. Energy information systems, often involving graphical dashboards, are gaining popularity in presenting energy performance metrics to occupants and operators in a (near) real-time fashion. Such an energy information system, called Building Agent, has been developed at NREL and incorporates a dashboard for public display. Each building is, by virtue of its purpose, location, and construction, unique. Thus, assessing building energy performance is possible only in a relative sense, as comparison of absolute energy use out of context is not meaningful. In some cases, performance can be judged relative to average performance of comparable buildings. However, in cases of high-performance building designs, such as NREL's Research Support Facility (RSF) discussed in this report, relative performance is meaningful only when compared to historical performance of the facility or to a theoretical maximum performance of the facility as estimated through detailed building energy modeling.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

THE SYSTEMATIC ERROR TEST FOR PSF CORRECTION IN WEAK GRAVITATIONAL LENSING SHEAR MEASUREMENT BY THE ERA METHOD BY IDEALIZING PSF

We improve the ellipticity of re-smeared artificial image (ERA) method of point-spread function (PSF) correction in a weak lensing shear analysis in order to treat the realistic shape of galaxies and the PSF. This is done by re-smearing the PSF and the observed galaxy image using a re-smearing function (RSF) and allows us to use a new PSF with a simple shape and to correct the PSF effect without any approximations or assumptions. We perform a numerical test to show that the method applied for galaxies and PSF with some complicated shapes can correct the PSF effect with a systematic error of less than 0.1%. We also apply the ERA method for real data of the Abell 1689 cluster to confirm that it is able to detect the systematic weak lensing shear pattern. The ERA method requires less than 0.1 or 1 s to correct the PSF for each object in a numerical test and a real data analysis, respectively.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2012

Controlling Capital Costs in High Performance Office Buildings: A Review of Best Practices for Overcoming Cost Barriers

This paper presents a set of 15 best practices for owners, designers, and construction teams of office buildings to reach high performance goals for energy efficiency, while maintaining a competitive budget. They are based on the recent experiences of the owner and design/build team for the Research Support Facility (RSF) on National Renewable Energy Facility's campus in Golden, CO, which showthat achieving this outcome requires each key integrated team member to understand their opportunities to control capital costs.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

SPC-3186 Rev 8 Reactor Support Frame and Outer Shield Build to Print Fabrication Specification

Idaho National Laboratory (INL) is developing a microreactor to produce electrical power utilizing a small nuclear core under the Microreactor Application Research Validation and Evaluation (MARVEL) program. This procurement specification defines the requirements for fabrication of the Reactor Support Frame (RSF) and Outer Shield.

21 - SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLAN↗
DOE OSTI2012

Rapid Application Development with OpenStudio: Preprint

This paper presents several case studies of rapidly implemented, audience-specific applications for whole building energy modeling and standards analysis. By tailoring each application to the audience and the task at hand, the required learning curve for new users was greatly reduced. Each case study used OpenStudio, the U.S. Department of Energy's middleware software development kit (SDK).OpenStudio provides an easy interface to the EnergyPlus whole building simulation engine, while extending its capability and providing higher-level functionality such as software interoperability, standards, analysis, and optimization. Each case study is unique in the technology employed to interface with OpenStudio as well as the methods used for user interaction and data presentation. Fourcase studies are presented.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

NREL's Sustainable Campus Overview

The high-performance buildings across the Energy Department's National Renewable Energy Laboratory's (NREL) South Table Mountain campus incorporate a number of state-of-the art energy efficiency and renewable energy technologies, making them models for sustainability. Each building, designed to meet the Gold or Platinum standards of the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED®) program, brings NREL closer to developing the campus of the future.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗