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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 811 records · Page 45
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Structural Integrity of a Wind Tunnel Balance

The National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) has been designing strain-gage balances for utilization in wind tunnels since its inception. The utilization of balances span over a wide variety of aerodynamic tests. A force balance is an inherently critically stressed component due to the requirements of measurement sensitivity. Research and analyses are done in order to investigate the structural integrity of the balances as well as developing an understanding of their performance in order to enhance their capability. Maximum loading occurs when all 6 components of the loads are applied simultaneously with their maximum value allowed (limit load). This circumstance normally does not occur in the wind tunnel. However, if it occurs, is the balance capable of handling the loads with an acceptable factor of safety? LaRC Balance 1621 was modeled and meshed in PATRAN for analysis in NASTRAN. For a complete analysis, it is necessary to consider all the load cases as well as use dense mesh near all the edges. Because of computer limitations, it is not possible to have one model with the dense mesh near all edges. In the present study, a dense mesh is limited to the surface corners where the cage and axial sections meet. Four different load combinations are used for the current analysis. Linear analysis is performed for each load case. In the case where the stress value is above linear elastic region, it is necessary to perform nonlinear analysis. It is also important to investigate the variables limiting the structural integrity of the balances. In order to investigate the possibility of modifying the existing balances to enhance the structural integrity, some modifications are done on this balance. The structural integrity of the balance after modification is investigated.

Karkehabadi, R.↗
NASA NTRS2007

Tropospheric Vertical Distribution of Tropical Atlantic Ozone Observed by TES during the Northern African Biomass Burning Season

We present vertical distributions of ozone from the Tropospheric Emission Spectrometer (TES) over the tropical Atlantic Ocean during January 2005. Between 10N and 20S, TES ozone retrievals have Degrees of Freedom for signal (DOF) around 0.7 - 0.8 each for tropospheric altitudes above and below 500 hPa. As a result, TES is able to capture for the first time from space a distribution characterized by two maxima: one in the lower troposphere north of the ITCZ and one in the middle and upper troposphere south of the ITCZ. We focus our analysis on the north tropical Atlantic Ocean, where most of previous satellite observations showed discrepancies with in-situ ozone observations and models. Trajectory analyses and a sensitivity study using the GEOS-Chem model confirm the influence of northern Africa biomass burning on the elevated ozone mixing ratios observed by TES over this region.

satellite observations↗
NASA NTRS2012

Complex Decision-Making Applications for the NASA Space Launch System

The Space Shuttle program is ending and elements of the Constellation Program are either being cancelled or transitioned to new NASA exploration endeavors. The National Aeronautics and Space Administration (NASA) has worked diligently to select an optimum configuration for the Space Launch System (SLS), a heavy lift vehicle that will provide the foundation for future beyond low earth orbit (LEO) large-scale missions for the next several decades. Thus, multiple questions must be addressed: Which heavy lift vehicle will best allow the agency to achieve mission objectives in the most affordable and reliable manner? Which heavy lift vehicle will allow for a sufficiently flexible exploration campaign of the solar system? Which heavy lift vehicle configuration will allow for minimizing risk in design, test, build and operations? Which heavy lift vehicle configuration will be sustainable in changing political environments? Seeking to address these questions drove the development of an SLS decision-making framework. From Fall 2010 until Spring 2011, this framework was formulated, tested, fully documented, and applied to multiple SLS vehicle concepts at NASA from previous exploration architecture studies. This was a multistep process that involved performing figure of merit (FOM)-based assessments, creating Pass/Fail gates based on draft threshold requirements, performing a margin-based assessment with supporting statistical analyses, and performing sensitivity analysis on each. This paper discusses the various methods of this process that allowed for competing concepts to be compared across a variety of launch vehicle metrics. The end result was the identification of SLS launch vehicle candidates that could successfully meet the threshold requirements in support of the SLS Mission Concept Review (MCR) milestone.

Lyles, Garry↗
NASA NTRS2012

Complex Decision-Making Applications for the NASA Space Launch System

The Space Shuttle program is ending and elements of the Constellation Program are either being cancelled or transitioned to new NASA exploration endeavors. NASA is working diligently to select an optimum configuration for the Space Launch System (SLS), a heavy lift vehicle that will provide the foundation for future beyond LEO large ]scale missions for the next several decades. Thus, multiple questions must be addressed: Which heavy lift vehicle will best allow the agency to achieve mission objectives in the most affordable and reliable manner? Which heavy lift vehicle will allow for a sufficiently flexible exploration campaign of the solar system? Which heavy lift vehicle configuration will allow for minimizing risk in design, test, build and operations? Which heavy lift vehicle configuration will be sustainable in changing political environments? Seeking to address these questions drove the development of an SLS decisionmaking framework. From Fall 2010 until Spring 2011, this framework was formulated, tested, fully documented, and applied to multiple SLS vehicle concepts at NASA from previous exploration architecture studies. This was a multistep process that involved performing FOM-based assessments, creating Pass/Fail gates based on draft threshold requirements, performing a margin-based assessment with supporting statistical analyses, and performing sensitivity analysis on each. This paper discusses the various methods of this process that allowed for competing concepts to be compared across a variety of launch vehicle metrics. The end result was the identification of SLS launch vehicle candidates that could successfully meet the threshold requirements in support of the SLS Mission Concept Review (MCR) milestone.

Lyles, Garry↗
NASA NTRS2012

Space Launch System Complex Decision-Making Process

The Space Shuttle program has ended and elements of the Constellation Program have either been cancelled or transitioned to new NASA exploration endeavors. The National Aeronautics and Space Administration (NASA) has worked diligently to select an optimum configuration for the Space Launch System (SLS), a heavy lift vehicle that will provide the foundation for future beyond low earth orbit (LEO) large-scale missions for the next several decades. From Fall 2010 until Spring 2011, an SLS decision-making framework was formulated, tested, fully documented, and applied to multiple SLS vehicle concepts at NASA from previous exploration architecture studies. This was a multistep process that involved performing figure of merit (FOM)-based assessments, creating Pass/Fail gates based on draft threshold requirements, performing a margin-based assessment with supporting statistical analyses, and performing sensitivity analysis on each. This paper focuses on the various steps and methods of this process (rather than specific data) that allowed for competing concepts to be compared across a variety of launch vehicle metrics in support of the successful completion of the SLS Mission Concept Review (MCR) milestone.

Lyles, Garry↗
NASA NTRS2014

Calibration Uncertainty in Ocean Color Satellite Sensors and Trends in Long-term Environmental Records

Launched in late 2011, the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (NPP) spacecraft is being evaluated by NASA to determine whether this sensor can continue the ocean color data record established through the Sea-Viewing Wide Field-of-view Sensor (SeaWiFS) and the MODerate resolution Imaging Spectroradiometer (MODIS). To this end, Goddard Space Flight Center generated evaluation ocean color data products using calibration techniques and algorithms established by NASA during the SeaWiFS and MODIS missions. The calibration trending was subjected to some initial sensitivity and uncertainty analyses. Here we present an introductory assessment of how the NASA-produced time series of ocean color is influenced by uncertainty in trending instrument response over time. The results help quantify the uncertainty in measuring regional and global biospheric trends in the ocean using satellite remote sensing, which better define the roles of such records in climate research.

environment↗
NASA NTRS2014

Flightdeck Automation Problems (FLAP) Model for Safety Technology Portfolio Assessment

NASA's Aviation Safety Program (AvSP) develops and advances methodologies and technologies to improve air transportation safety. The Safety Analysis and Integration Team (SAIT) conducts a safety technology portfolio assessment (PA) to analyze the program content, to examine the benefits and risks of products with respect to program goals, and to support programmatic decision making. The PA process includes systematic identification of current and future safety risks as well as tracking several quantitative and qualitative metrics to ensure the program goals are addressing prominent safety risks accurately and effectively. One of the metrics within the PA process involves using quantitative aviation safety models to gauge the impact of the safety products. This paper demonstrates the role of aviation safety modeling by providing model outputs and evaluating a sample of portfolio elements using the Flightdeck Automation Problems (FLAP) model. The model enables not only ranking of the quantitative relative risk reduction impact of all portfolio elements, but also highlighting the areas with high potential impact via sensitivity and gap analyses in support of the program office. Although the model outputs are preliminary and products are notional, the process shown in this paper is essential to a comprehensive PA of NASA's safety products in the current program and future programs/projects.

Ancel, Ersin↗
NASA NTRS2015

Correlating Mineralogy and Amino Acid Contents of Milligram-Scale Murchison Carbonaceous Chondrite Samples

Amino acids, the building blocks of proteins, have been found to be indigenous in most of the carbonaceous chondrite groups. The abundances of amino acids, as well as their structural, enantiomeric and isotopic compositions differ significantly among meteorites of different groups and petrologic types. This suggests that there is a link between parent-body conditions, mineralogy and the synthesis and preservation of amino acids (and likely other organic molecules). However, elucidating specific causes for the observed differences in amino acid composition has proven extremely challenging because samples analyzed for amino acids are typically much larger ((is) approximately 100 mg powders) than the scale at which meteorite heterogeneity is observed (sub mm-scale differences, (is) approximately 1-mg or smaller samples). Thus, the effects of differences in mineralogy on amino acid abundances could not be easily discerned. Recent advances in the sensitivity of instrumentation have made possible the analysis of smaller samples for amino acids, enabling a new approach to investigate the link between mineralogical con-text and amino acid compositions/abundances in meteorites. Through coordinated mineral separation, mineral characterization and highly sensitive amino acid analyses, we have performed preliminary investigations into the relationship between meteorite mineralogy and amino acid composition. By linking amino acid data to mineralogy, we have started to identify amino acid-bearing mineral phases in different carbonaceous meteorites. The methodology and results of analyses performed on the Murchison meteorite are presented here.

Burton, Aaron, S.↗
DOE OSTI2011

Multi-jet Merging with NLO Matrix Elements

In the algorithm presented here, the ME+PS approach to merge samples of tree-level matrix elements into inclusive event samples is combined with the POWHEG method, which includes exact next-to-leading order matrix elements in the parton shower. The advantages of the method are discussed and the quality of its implementation in SHERPA is exemplified by results for e{sup +}e{sup -} annihilation into hadrons at LEP, for deep-inelastic lepton-nucleon scattering at HERA, for Drell-Yan lepton-pair production at the Tevatron and for W{sup +}W{sup -}-production at LHC energies. The simulation of hard QCD radiation in parton-shower Monte Carlos has seen tremendous progress over the last years. It was largely stimulated by the need for more precise predictions at LHC energies where the large available phase space allows additional hard QCD radiation alongside known Standard Model processes or even signals from new physics. Two types of algorithms have been developed, which allow to improve upon the soft-collinear approximations made in the parton shower, such that hard radiation is simulated according to exact matrix elements. In the ME+PS approach [1] higher-order tree-level matrix elements for different final-state jet multiplicity are merged with each other and with subsequent parton shower emissions to generate an inclusive sample. Such a prescription is invaluable for analyses which are sensitive to final states with a large jet multiplicity. The only remaining deficiency of such tree-level calculations is the large uncertainty stemming from scale variations. The POWHEG method [2] solves this problem for the lowest multiplicity subprocess by combining full NLO matrix elements with the parton shower. While this leads to NLO accuracy in the inclusive cross section and the exact radiation pattern for the first emission, it fails to describe higher-order emissions with improved accuracy. Thus it is not sufficient if final states with high jet multiplicities are considered. With the complementary advantages of these two approaches, the question arises naturally whether it would be possible to combine them into an even more powerful one. Such a combined algorithm was independently developed in [5] and [6]. Here a summary of the algorithm is given and predictions from corresponding Monte-Carlo predictions are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

GREENHOUSE GAS REDUCTION POTENTIAL WITH COMBINED HEAT AND POWER WITH DISTRIBUTED GENERATION PRIME MOVERS - ASME 2012

Pending or recently enacted greenhouse gas regulations and mandates are leading to the need for current and feasible GHG reduction solutions including combined heat and power (CHP). Distributed generation using advanced reciprocating engines, gas turbines, microturbines and fuel cells has been shown to reduce greenhouse gases (GHG) compared to the U.S. electrical generation mix due to the use of natural gas and high electrical generation efficiencies of these prime movers. Many of these prime movers are also well suited for use in CHP systems which recover heat generated during combustion or energy conversion. CHP increases the total efficiency of the prime mover by recovering waste heat for generating electricity, replacing process steam, hot water for buildings or even cooling via absorption chilling. The increased efficiency of CHP systems further reduces GHG emissions compared to systems which do not recover waste thermal energy. Current GHG mandates within the U.S Federal sector and looming GHG legislation for states puts an emphasis on understanding the GHG reduction potential of such systems. This study compares the GHG savings from various state-of-the- art prime movers. GHG reductions from commercially available prime movers in the 1-5 MW class including, various industrial fuel cells, large and small gas turbines, micro turbines and reciprocating gas engines with and without CHP are compared to centralized electricity generation including the U.S. mix and the best available technology with natural gas combined cycle power plants. The findings show significant GHG saving potential with the use of CHP. Also provided is an exploration of the accounting methodology for GHG reductions with CHP and the sensitivity of such analyses to electrical generation efficiency, emissions factors and most importantly recoverable heat and thermal recovery efficiency from the CHP system.

03 NATURAL GAS↗
DOE OSTI2012

DETERMINATION OF THE DISTRIBUTION AND INVENTORY OF RADIONUCLIDES WITHIN A SAVANNAH RIVER SITE WATERWAY

An investigation was conducted to evaluate the radionuclide inventory within the Lower Three Runs (LTR) Integrator Operable Unit (IOU) at the U.S. Department of Energy’s (DOE’s) Savannah River Site (SRS). The scope of this effort included the analysis of previously existing sampling and analysis data as well as additional streambed and floodplain sampling and analysis data acquired to delineate horizontal and vertical distributions of the radionuclide as part of the ongoing SRS environmental restoration program, and specifically for the LTR IOU program. While cesium-137 (Cs-137) is the most significant and abundant radionuclide associated with the LTR IOU it is not the only radionuclide, hence the scope included evaluating all radionuclides present and includes an evaluation of inventory uncertainty for use in sensitivity and uncertainty analyses. The scope involved evaluation of the radionuclide inventory in the P-Reactor and RReactor cooling water effluent canal systems, PAR Pond (including Pond C) and the floodplain and stream sediment sections of LTR between the PAR Pond Dam and the Savannah River. The approach taken was to examine all of the available Sediment and Sediment/Soil analysis data available along the P- and R-Reactor cooling water re-circulation canal system, the ponds situated along those canal reaches and along the length of LTR below Par Pond dam. By breaking the IOU into a series of sub-components and sub-sections, the mass of contaminated material was estimated and a representative central concentration of each radionuclide was computed for each compartment. The radionuclide inventory associated with each sub-compartment was then aggregated to determine the total radionuclide inventory that represented the full LTR IOU. Of special interest was the inventory of Cs-137 due to its role in contributing to the potential dose to an offsite member of the public. The overall LTR IOU inventory of Cs-137 was determined to be 75.5 Ci, which is similar to two earlier estimates. This investigation provides an independent, ground-up estimate of Cs-137 inventory in LTR IOU utilizing the most recent field data.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Impact of sub-core scale heterogeneity on CO2/brine multiphase flow for geological carbon storage in the Minnelusa sandstone

CO2 geological storage in deep saline aquifers is a mitigation option for CO2 emissions due to its large storage capacity and immediate accessibility. Accurately determining the CO2-brine relative permeability curves is key to the evaluation of CO2 injectivity and sweep efficiency in reservoir simulation as well as the CO2 injection in the field. This study highlights the remarkable effects of sub-core scale heterogeneity on the CO2-brine multiphase flow properties of the Minnelusa Sandstone in Wyoming. Two unsteady state CO2-brine drainage experiments were performed on the two samples. The first sample exhibits slanted laminated structure, while the second one represents a more homogeneous sandstone system. The CO2 saturation distributions during drainage reveals that the main variation in multiphase flow properties of two core samples were attributed to the porosity distribution that leads to the capillary pressure heterogeneity. Assisted history matching was used to obtain the respective relative permeability curves, which suggests heterogeneity-dependent behavior. In addition, sensitive and uncertainty analyses indicate that physical and petro-physical properties of low-porosity and low-permeability bedding layers exert marked effects on CO2 front breakthrough time and brine production. The results presented in this study help to gain insight into the CO2-brine multiphase flow properties in heterogeneous sandstones and can pave the way for the upscaling of CO2 migration and field-scale simulation accurately. This work is funded under the Department of Energy CarbonSAFE program (awards DE-FE0031624 DE0031891).

Kou, Zuhao↗
DOE OSTI2022

Life Cycle Assessment for Closed-Loop Pumped Hydropower Energy Storage in the United States

The federal government has initiated an aggressive set of policies to achieve a net-zero carbon emission goal for the electricity sector by 2050. As a result, rapid growth in deployment of renewable energy technologies is expected. Most commercially mature technologies are temporally variable and do not provide grid inertia, while renewable technologies with high projected deployment have intermittent generation methods. Energy storage technologies are needed to both dispatch power on-demand and help provide the needed grid inertia. Pumped storage hydro (PSH) is a well-established technology that has gained renewed interest in recent years offering energy-balancing, grid stability, control of electrical network frequency, and large-scale storage capacity. For widespread adoption of PSH, more information is needed regarding its current life cycle environmental impacts. The objective of this study is to perform a full life cycle assessment (LCA) of new closed-loop PSH in the U.S. The functional unit for this study is 1 kWh of electrical power delivered to the grid and the base case project lifetime is 80 years. The life cycle inventory for this project accounts for all material and energy flows associated with the green-field construction, operation, maintenance, and decommissioning of a closed-loop PSH plant in the U.S. Collected data represents a range of potential PSH specifications and geographic locations coming from all prospective closed-loop PSH installations in the U.S. with data available. In addition, existing PSH installations are used to provide assumptions for inventory inputs. Results presented will include the global warming potential (GWP IPCC 100a) and Energy Return on Investment (EROI) from our base case (average PSH installation) as well as from scenario analyses and model sensitivity. These results will be compared to the impacts from existing PSH sites and alternate storage technologies. Methods align with the assumptions and guidelines put in place by previous PSH LCAs to ensure an accurate comparison with the results from this report.

ENERGY PLANNING, POLICY, AND ECONOMY,HYDRO ENERGY↗
DOE OSTI2013

Determination of the Distribution and Inventory of Radionuclides within a Savannah River Site Waterway - 13202

An investigation was conducted to evaluate the radionuclide inventory within the Lower Three Runs (LTR) Integrator Operable Unit (IOU) at the U.S. Department of Energy's (DOE's) Savannah River Site (SRS). The scope of this effort included the analysis of previously existing sampling and analysis data as well as additional stream bed and flood plain sampling and analysis data acquired to delineate horizontal and vertical distributions of the radionuclide as part of the ongoing SRS environmental restoration program, and specifically for the LTR IOU program. While cesium-137 (Cs-137) is the most significant and abundant radionuclide associated with the LTR IOU it is not the only radionuclide, hence the scope included evaluating all radionuclides present and includes an evaluation of inventory uncertainty for use in sensitivity and uncertainty analyses. The scope involved evaluation of the radionuclide inventory in the P-Reactor and R-Reactor cooling water effluent canal systems, PAR Pond (including Pond C) and the flood plain and stream sediment sections of LTR between the PAR Pond Dam and the Savannah River. The approach taken was to examine all of the available Sediment and Sediment/Soil analysis data available along the P- and R-Reactor cooling water re-circulation canal system, the ponds situated along those canal reaches and along the length of LTR below Par Pond dam. By breaking the IOU into a series of sub-components and sub-sections, the mass of contaminated material was estimated and a representative central concentration of each radionuclide was computed for each compartment. The radionuclide inventory associated with each sub-compartment was then aggregated to determine the total radionuclide inventory that represented the full LTR IOU. Of special interest was the inventory of Cs-137 due to its role in contributing to the potential dose to an offsite member of the public. The overall LTR IOU inventory of Cs-137 was determined to be 2.87 E+02 GBq, which is similar to two earlier estimates. This investigation provides an independent, ground-up estimate of Cs-137 inventory in LTR IOU utilizing the most recent field data. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Parametric analyses of single-zone thorium-fueled molten salt reactor fuel cycle options

Analyses of fuel cycle options based on thorium-fueled Molten Salt Reactors (MSRs) have been performed in support of fuel cycle screening and evaluation activities for the United States Department of Energy. The MSR options considered are based on thermal spectrum MSRs with 3 different separations levels: full recycling, limited recycling, and 'once-through' operation without active separations. A single-fluid, single-zone 2250 MWth (1000 MWe) MSR concept consisting of a fuel-bearing molten salt with graphite moderator and reflectors was used as the basis for this study. Radiation transport and isotopic depletion calculations were performed using SCALE 6.1 with ENDF/B-VII nuclear data. New methodology developed at Oak Ridge National Laboratory (ORNL) enables MSR analysis using SCALE, modeling material feed and removal by taking user-specified parameters and performing multiple SCALE/TRITON simulations to determine the resulting equilibrium operating conditions. Parametric analyses examined the sensitivity of the performance of a thorium MSR to variations in the separations efficiency for protactinium and fission products. Results indicate that self-sustained operation is possible with full or limited recycling but once-through operation would require an external neutron source. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Using Calibrated Sodium Data for Preliminary Validation of the SRT Code for Advanced Reactors

Various types of non-light water reactors are currently engaged in the U.S. licensing process. Because of inherent differences compared with well-established large light water reactors, appropriate assessment tools are needed. Specifically, source term analysis, which determines environmental dose impacts from potential accident scenarios, is a crucial part of design and licensing. The U.S. Nuclear Regulatory Commission has emphasized the importance of mechanistic source term analysis for advanced reactor deployments. To align with these needs, Argonne National Laboratory has developed the Simplified Radionuclide Transport (SRT) source term analysis code for metal fuel Sodium-cooled Fast Reactors (SFRs) and microreactors. SRT conducts time-dependent radionuclide transport and retention in SFRs for core and ex-core radionuclide source accident sequences. The main objective of SRT is to provide rapid sensitivity and uncertainty analyses, incorporating parametric uncertainties and summarizing probabilistic results. As part of the code validation process, a study focused on the bubble scrubbing module was performed using an experiment recently carried out by the University of Wisconsin-Madison. Based on the analysis, the modeling approach in SRT provides accurate results for small and large aerosols, while slight underprediction of radionuclide aerosol removal are observed for medium sized aerosols. However, the deviation is minor, considering the highly uncertain phenomenon and range of results, and is in the conservative direction. In addition, uncertainty information derived from the experiments is further implemented, reflecting the actual span of parameters, which leads to enhanced agreement with code predictions. The results demonstrate that SRT provides reasonable predictions for the bubble scrubbing process in sodium pool.

Kam, Dong Hoon↗
DOE OSTI2013

Mechanical Design of a New Injector Cryomodule 2-Cell Cavity at CEBAF

As a part of Jefferson Lab’s 12 GeV upgrade, a new injector superconducting RF cryomodule is required. This unit consists of a 2-cell and 7-cell cavity, with the latter being refurbished from an existing cavity. The new 2-cell cavity requires electromagnetic design and optimization followed by mechanical design analyses. The electromagnetic design is reported elsewhere. This paper aims to present the procedures and conclusions of the analyses on cavity tuning sensitivity, pressure sensitivity, upset condition pressure induced stresses, and structural vibration frequencies. The purposes of such analyses include: 1) provide reference data for cavity tuner design; 2) examine the structural integrity of the cavity; and 3) evaluate the 2-cell cavity’s resistance to microphonics. Design issues such as the location of stiffening rings, effect of tuner stiffness on cavity stress, choice of cavity wall thickness, etc. are investigated by conducting extensive finite element analyses. Progress in fabrication of the 2-cell cavity is also reported.

43 PARTICLE ACCELERATORS↗