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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 1,153 records · Page 64
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Sex ratio of Western Bluebirds ( Sialia mexicana ) is mediated by phenology and clutch size

Mothers may produce more of one sex to maximize their fitness if there are differences in the cost of producing each sex or there are differences in their relative reproductive value. Breeding date and clutch size are known to influence offspring sex ratios in birds through sex differences in dispersal, social behaviours, differential mortality and available food resources. We tested whether breeding date, clutch size and drought conditions influenced offspring sex ratios in a sexually size-monomorphic species, the Western Bluebird Sialia mexicana, by interrogating a 21-year dataset. After controlling for differential mortality, we found that hatch dates late in the breeding season were associated with the production of more females, suggesting that the value of producing males declines as the breeding season progresses. When clutch size was taken into account, small clutches yielded significantly more females late in the breeding season than in the early and middle parts of the breeding season, which produced significantly more males. Here, large clutches early in the season tended to produce more females, although this was not significant. Drought severity was not correlated with sex ratio adjustment. We propose and discuss several explanations for these patterns, including male offspring, but not female offspring, acting as helpers, increased female nestling provisioning late in the breeding season, differences in food abundance and egg-laying order. Future work will help to uncover the mechanisms leading to these patterns. Identifying patterns and mechanisms of sex ratio skew from long-term datasets is important for informing predictions regarding life-history trade-offs in wildlife populations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Root system architecture in cereals: progress, challenges and perspective

We report roots are essential multifunctional plant organs involved in water and nutrient uptake, metabolite storage, anchorage, mechanical support, and interaction with the soil environment. Understanding of this ‘hidden half’ provides potential for manipulation of root system architecture (RSA) traits to optimize resource use efficiency and grain yield in cereal crops. Unfortunately, root traits are highly neglected in breeding due to the challenges of phenotyping, but could have large rewards if the variability in RSA traits can be fully exploited. Until now, a plethora of genes have been characterized in detail for their potential role in improving RSA. The use of forward genetics approaches to find sequence variations in genes underpinning desirable RSA would be highly beneficial. Advances in computer vision applications have allowed image-based approaches for high-throughput phenotyping of RSA traits that can be used by any laboratory worldwide to make progress in understanding root function and dissection of the genetics. At the same time, the frontiers of root measurement include non-invasive methods like X-ray computer tomography and magnetic resonance imaging that facilitate new types of temporal studies. Root physiology and ecology are further supported by spatiotemporal root simulation modeling. The discovery of component traits providing improved resilience and yield advantage in target environments is a key necessity for mainstreaming root-based cereal breeding. The integrated use of pan-genome resources, now available in most cereals, coupled with new in-field phenotyping platforms has the potential for precise selection of superior genotypes with improved RSA.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

IMPLEMENTATION OF DETAILED CHEMISTRY MECHANISMS IN ENGINE SIMULATIONS

The stiffness of large chemistry mechanisms has been proved to be a major hurdle toward predictive engine simulations. As a result, detailed chemistry mechanisms with a few thousand species need to be reduced based on target conditions so that they can be accommodated within the available computational resources. The computational cost of simulations typically increases super-linearly with the number of species and reactions. This work aims to bring detailed chemistry mechanisms within the realm of engine simulations by coupling the framework of unsteady flamelets and fast chemistry solvers. A previously developed tabulated flamelet model (TFM) framework for nonpremixed combustion was used in this study. The flamelet solver consists of the traditional operator-splitting scheme with variable coefficient ordinary differential equation (ODE) solver (VODE) and a numerical Jacobian for solving the chemistry. In order to use detailed mechanisms with thousands of species, a new framework with the Livermore solver for ODEs in sparse form (LSODES) chemistry solver and an analytical Jacobian was implemented in this work. Results from 1D simulations show that with the new framework, the computational cost is linearly proportional to the number of species in a given chemistry mechanism. As a result, the new framework is 2-3 orders of magnitude faster than the conventional variable coefficient ODE (VODE) solver for large chemistry mechanisms. This new framework was used to generate unsteady flamelet libraries for ndodecane using a detailed chemistry mechanism with 2755 species and 11,173 reactions. The engine combustion network (ECN) spray A experiments, which consist of an igniting n-dodecane spray in turbulent, high-pressure engine conditions are simulated using large eddy simulations (LES) coupled with detailed mechanisms. A grid with 0.06 mm minimum cell size and 22 x 10(6) peak cell count was implemented. The framework is validated across a range of ambient temperatures against ignition delay and liftoff lengths (LOLs). Qualitative results from the simulations were compared against experimental OH and CH2O planar laser-induced fluorescence (PLIF) data. The models are able to capture the spatial and temporal trends in species compared to those observed in the experiments. Quantitative and qualitative comparisons between the predictions of the reduced and detailed mechanisms are presented in detail. The main goal of this study is to demonstrate that detailed reaction mechanisms (similar to 1000 species) can now be used in engine simulations with a linear increase in computation cost with number of species during the tabulation process and a small increase in the 3D simulation cost.

Kundu, Prithwish↗
DOE OSTI2014

MO-E-18C-06: Enriching Medical Physics Education By Visualizing The Invisible

Purpose: To enhance the understanding of medical physics concepts and develop higher levels of learning relating to invisible physics phenomena such as radiation. To provide medical physics educators in all countries of the world with understanding of knowledge structures in the human brain, the different levels of learning, and the types of knowledge required for higher level functions such as problem solving, creative innovations, and applied clinical applications. To provide medical physics educators with an open access resource (tool) that they can use in their teaching activities to enrich and elevate the level of learning for their students, residents, etc. with respect to the invisible realm of medical physics. Methods: An experienced clinical medical physicist and educator has created and provided with open access three complementary web-based resources to achieve the purposes described above. One is a module focusing on the medical physics learning process with respect to mental knowledge structures, how they relate to outcomes and applications, and learning activities that are required to develop the required knowledge structures. The second is an extensive set of visuals that educators can use in their activities (classes, small group discussions, etc.) to visualize the invisible. The third is an interactive online simulation where learners can adjust factors and visually observe changes in x-radiation.These resources are available online at www.BLINDED FOR REVIEW . Results: Medical physics education, especially for non-physicists, is becoming much more interesting and useful especially with respect to invisible radiation. The global impact is that medical imaging professionals can be more effective in optimizing x-ray imaging procedures and risk management when they have knowledge levels that enhance problem solving, innovation, and creativity. Conclusion: Medical physics educators in all institutions can be much more effective and efficient in the sharing of their knowledge and experience when enhanced with high-quality visuals.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
DOE OSTI2015

MO-A-213-00: Economics Update

The purpose of this session is to introduce attendees to the healthcare reimbursement system and how it applies to the clinical work of a Medical Physicist. This will include general information about the different categories of payers and payees, how work is described by CPT© codes, and how various payers set values for this work in different clinical settings. 2015 is a year of significant changes to the payment system. Many CPT© codes have been deleted and replaced with new CPT© codes. These codes define some of the most common work performed in our clinics including treatment planning and delivery. This presentation will describe what work is encompassed in these codes and will give attendees an overview of the changes for 2015 as they apply to radiation oncology. Finally, some insight into what can be expected during 2016 will be presented. This includes what information is typically released by the Centers for Medicaid & Medicare Services (CMS) during the year and how we as an organization respond. This will include ways members can interact with the AAPM professional economics committee and other resources members may find helpful. Learning Objectives: Basics of how Medicare is structured and how reimbursement rates are set. Basic understanding of proposed changes to the 2016 Medicare rules. What resources are available from the AAPM and how to interact with the professional economics committee. Ownership in pxAlpha, LLC, a medical device start up company.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2015

MO-A-213-01: 2015 Economics Update Part 1

The purpose of this session is to introduce attendees to the healthcare reimbursement system and how it applies to the clinical work of a Medical Physicist. This will include general information about the different categories of payers and payees, how work is described by CPT© codes, and how various payers set values for this work in different clinical settings. 2015 is a year of significant changes to the payment system. Many CPT© codes have been deleted and replaced with new CPT© codes. These codes define some of the most common work performed in our clinics including treatment planning and delivery. This presentation will describe what work is encompassed in these codes and will give attendees an overview of the changes for 2015 as they apply to radiation oncology. Finally, some insight into what can be expected during 2016 will be presented. This includes what information is typically released by the Centers for Medicaid & Medicare Services (CMS) during the year and how we as an organization respond. This will include ways members can interact with the AAPM professional economics committee and other resources members may find helpful. Learning Objectives: Basics of how Medicare is structured and how reimbursement rates are set. Basic understanding of proposed changes to the 2016 Medicare rules. What resources are available from the AAPM and how to interact with the professional economics committee. Ownership in pxAlpha, LLC, a medical device start up company.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2015

MO-A-213-02: 2015 Economics Update Part 2

The purpose of this session is to introduce attendees to the healthcare reimbursement system and how it applies to the clinical work of a Medical Physicist. This will include general information about the different categories of payers and payees, how work is described by CPT© codes, and how various payers set values for this work in different clinical settings. 2015 is a year of significant changes to the payment system. Many CPT© codes have been deleted and replaced with new CPT© codes. These codes define some of the most common work performed in our clinics including treatment planning and delivery. This presentation will describe what work is encompassed in these codes and will give attendees an overview of the changes for 2015 as they apply to radiation oncology. Finally, some insight into what can be expected during 2016 will be presented. This includes what information is typically released by the Centers for Medicaid & Medicare Services (CMS) during the year and how we as an organization respond. This will include ways members can interact with the AAPM professional economics committee and other resources members may find helpful. Learning Objectives: Basics of how Medicare is structured and how reimbursement rates are set. Basic understanding of proposed changes to the 2016 Medicare rules. What resources are available from the AAPM and how to interact with the professional economics committee. Ownership in pxAlpha, LLC, a medical device start up company.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2023

FFTX-IRIS: Towards Performance Portability and Heterogeneity for SPIRAL Generated Code

FFTX-IRIS is a dynamic system to efficiently utilize novel heterogeneous platforms. This system links two next-generation frameworks, FFTX and IRIS, to navigate the complexity of different hardware architectures. FFTX provides a runtime code generation framework for high-performance Fast Fourier Transform kernels. IRIS runtime provides portability and multi-device heterogeneity, allowing computation on any available compute resource. Together, FFTX-IRIS enables code generation, seamless portability, and performance without user involvement. We show the design of the FFTX-IRIS system along with an evaluation of various small FFT benchmarks. We also demonstrate multi-device heterogeneity of FFTX-IRIS with a larger stencil application.

Rao, Sanil↗
DOE OSTI2014

National Geothermal Database

THE NGDS IS A USER-FRIENDLY, WEB-BASED APPLICATION TO SUPPORT FINDING, VISUALIZING, MAPPING, AND ACQUISITION OF DATA BY END-USERS. THIS APPLICATION ALLOWS USERS TO DISCOVER AND ACCESS RESOURCES MADE AVAILABLE ACROSS ALL NGDS NODES, AND TO SEARCH FOR DATA ACROSS THE SYSTEM BASED ON TOPIC, LOCATION, AND OR OTHER CRITERIA. STANDARDIZED METADATA DESCRIBING EACH DATASET PROVIDES THE USER WITH THE INFORMATION NECESSARY TO DETERMINE THE UTILITY OF THAT DATASET FOR THEIR PURPOSES. GEOGRAPHIC DATASETS CAN BE VISUALIZED THROUGH A MAP INTERFACE THAT ALLOWS USERS TO INSPECT THE DETAILS OF INDIVIDUAL DATA POINTS (E.G. WELLS, TEMPERATURE MEASUREMENTS, ETC.) FROM PROPERLY FORMATTED DATASETS. IN ADDITION TO VISUALIZATION WITHIN THE APPLICATION, THE INTERFACE PROVIDES THE INFORMATION NECESSARY FOR USERS TO ACCESS THE DATA FROM OTHER APPLICATIONS.

Source record↗
DOE OSTI2018

Dispatch Table

The Energy Market Price Response (EMPR) service is provided by the device, which shifts demand from high price periods in the day to low price periods. The device would consume energy when prices are low and release energy (or defer consumption) when prices are high. This load shifting benefits the individual consumers and society in general by shifting consumption to periods when production resources are available at lower costs. The service could be driven by price forecasts of the day-ahead market or shorter time periods. The service could be facilitated by demand response aggregators, utilities, or other load serving entities.

Edmunds, Thomas↗
DOE OSTI2021

De novo transcriptome analysis of white teak (Gmelina arborea Roxb) wood reveals critical genes involved in xylem development and secondary metabolism

Gmelina arborea Roxb is a fast-growing tree species of commercial importance for tropical countries due to multiple industrial uses of its wood. Wood is primarily composed of thick secondary cell walls of xylem cells which imparts the strength to the wood. Identification of the genes involved in the secondary cell wall biosynthesis as well as their cognate regulators is crucial to understand how the production of wood occurs and serves as a starting point for developing breeding strategies to produce varieties with improved wood quality, better paper pulping or new potential uses such as biofuel production. In order to gain knowledge on the molecular mechanisms and gene regulation related with wood development in white teak, a de novo sequencing and transcriptome assembly approach was used employing secondary cell wall synthesizing cells from young white teak trees. For generation of transcriptome, RNA-seq reads were assembled into 110,992 transcripts and 49,364 genes were functionally annotated using plant databases; 5071 GO terms and 25,460 SSR markers were identified within xylem transcripts and 10,256 unigenes were assigned to KEGG database in 130 pathways. Among transcription factor families, C2H2, C3H, bLHLH and MYB were the most represented in xylem. Differential gene expression analysis using leaves as a reference was carried out and a total of 20,954 differentially expressed genes were identified including monolignol biosynthetic pathway genes. The differential expression of selected genes (4CL, COMT, CCoAOMT, CCR and NST1) was validated using qPCR. We report the very first de novo transcriptome of xylem-related genes in this tropical timber species of commercial importance and constitutes a valuable extension of the publicly available transcriptomic resource aimed at fostering both basic and breeding studies.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Diversity waves in collapse-driven population dynamics

Populations of species in ecosystems are often constrained by availability of resources within their environment. In effect this means that a growth of one population, needs to be balanced by comparable reduction in populations of others. In neutral models of biodiversity all populations are assumed to change incrementally due to stochastic births and deaths of individuals. Here we propose and model another redistribution mechanism driven by abrupt and severe collapses of the entire population of a single species freeing up resources for the remaining ones. This mechanism may be relevant e.g. for communities of bacteria, with strain-specific collapses caused e.g. by invading bacteriophages, or for other ecosystems where infectious diseases play an important role. The emergent dynamics of our system is cyclic ‘‘diversity waves’’ triggered by collapses of globally dominating populations. The population diversity peaks at the beginning of each wave and exponentially decreases afterwards. Species abundances are characterized by a bimodal time-aggregated distribution with the lower peak formed by populations of recently collapsed or newly introduced species while the upper peak - species that has not yet collapsed in the current wave. In most waves both upper and lower peaks are composed of several smaller peaks. This self-organized hierarchical peak structure has a long-term memory transmitted across several waves. It gives rise to a scale-free tail of the time-aggregated population distribution with a universal exponent of 1.7. We show that diversity wave dynamics is robust with respect to variations in the rules of our model such as diffusion between multiple environments, species-specific growth and extinction rates, and bet-hedging strategies.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Commercial and Residential Hourly Load Profiles for All Typical Meteorological Year 3 (TMY3) Locations in the United States

One way to achieve grid flexibility is to shed or shift demand to align with changing grid needs. To facilitate this, it is critical to understand how and when energy is used. High-quality end-use load profiles (EULPs) provide this information and can help cities, states, and utilities understand the time-sensitive value of energy efficiency, demand response, and distributed energy resources. Publicly available EULPs have traditionally had limited application because of age and incomplete geographic representation. To help fill this gap, the U.S. Department of Energy funded a 3-year project, End-Use Load Profiles for the U.S. Building Stock, that culminated in this publicly available dataset of calibrated and validated 15-minute-resolution load profiles for all major residential and commercial building types and end uses across all climate regions in the United States. These EULPs were created by calibrating the ResStock and ComStock physics-based building stock models using many different measured datasets, as described in the "Technical Report Documenting Methodology" linked in the submission.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Hydraulic fracture characterization by integrating multidisciplinary data from the Hydraulic Fracturing Test Site 2 (HFTS-2)

Various technologies have traditionally been used to monitor and describe hydraulic fractures from different perspectives. This work demonstrates the value of data integration for hydraulic fracture characterization when multiple data resources are available. The Hydraulic Fracturing Test Site 2 (HFTS 2) is a hydraulic fracturing research project in the Delaware Basin with multiple surveillance techniques including fiber optics sensing, microseismic, pressure/temperature gauges, etc. We integrated the multidisciplinary data from the HFTS-2 to characterize hydraulic fractures. The integrated data revealed interesting fracture propagation features including layering, vertical propagation affected by pore pressure gradient, and different microseismic activities due to difference in-situ conditions. Furthermore, these findings can be insightful for understanding hydraulic fracture propagation. The comparison among multiple surveillance data also helps us to evaluate the roles of various surveillance technologies and provides us experience to make informative decisions depending on different monitoring objectives.

58 GEOSCIENCES↗
DOE OSTI2017

Accomplishments of the Heavy Electron Particle Accelerator Program

The Muon Accelerator Program has completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of lepton colliders from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using μ storage rings for neutrinos. The key components of the muon collider scenarios are a high-intensity proton source, a multi MW target and transport system for π capture, a front end system for bunching, energy compression and initial cooling of μ's, muon cooling systems to obtain intense μ+ and μ- bunches, acceleration up to multiTeV energies, and a collider ring with detectors for high luminosity collisions. For a neutrino factory a similar system could be used but with a racetrack storage ring for ν production and without the cooling needed for high luminosity collisions. Feasible designs and detailed simulations of all of these components have been obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and clearly associated physics goals become apparent.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

libEnsemble: A complete Python toolkit for dynamic ensembles of calculations

Almost all science and engineering applications eventually stop scaling: their runtime no longer decreases as available computational resources increase. Therefore, many applications will struggle to efficiently use emerging extreme-scale high-performance, parallel, and distributed systems. libEnsemble is a complete Python toolkit and workflow system for intelligently driving ensembles of experiments or simulations at massive scales. It enables and encourages multidisciplinary design, decision, and inference studies portably running on laptops, clusters, and supercomputers.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2013

Feasibility Study of Economics and Performance of Biomass Power Generation at the Former Farmland Industries Site in Lawrence, Kansas - A Study Prepared in Partnership with the Environmental Protection Agency for the RE-Powering America's Land Initiative: Siting Renewable Energy on Potentially Contaminated Land and Mine Sites

Under the RE-Powering America's Land initiative, the U.S. Environmental Protection Agency (EPA) provided funding to the National Renewable Energy Laboratory (NREL) to support a feasibility study of biomass renewable energy generation at the former Farmland Industries site in Lawrence, Kansas. Feasibility assessment team members conducted a site assessment to gather information integral to this feasibility study. Information such as biomass resources, transmission availability, on-site uses for heat and power, community acceptance, and ground conditions were considered.

09 BIOMASS FUELS↗
DOE OSTI2013

Physiology and Genetics of Biogenic Methane-Production from Acetate

Biomass conversion catalyzed by methanogenic consortia is a widely available, renewable resource for both energy production and waste treatment. The efficiency of this process is directly dependent upon the interaction of three metabolically distinct groups of microorganisms; the fermentative and acetogenic Bacteria and the methanogenic Archaea. One of the rate limiting steps in the degradation of soluble organic matter is the dismutation of acetate, a predominant intermediate in the process, which accounts for 70 % or more of the methane produced by the methanogens. Acetate utilization is controlled by regulation of expression of carbon monoxide dehydrogensase (COdh), which catalyzes the dismutation of acetate. However, physiological and molecular factors that control differential substrate utilization have not been identified in these Archaea. Our laboratory has identified sequence elements near the promoter of the gene (cdh) encoding for COdh and we have confirmed that these sequences have a role in the in vivo expression of cdh. The current proposal focuses on identifying the regulatory components that interact with DNA and RNA elements, and identifying the mechanisms used to control cdh expression.

59 BASIC BIOLOGICAL SCIENCES↗