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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 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Central Park Ecological Conservation: Assessing Tree Health Conditions in New York City’s Central Park with NASA Earth Observation Data

The Central Park Conservancy stewards New York City’s iconic Central Park with a mission to preserve the park for all. This mission is complicated by the spread of Dutch elm disease (DED) which has threatened the culturally and ecologically significant American elm tree (Ulmus americana). Central Park is home to one of the largest and last remaining urban concentrations of American elm and the Conservancy currently protects them through integrated pest management. This paper discusses an interdisciplinary feasibility study that assessed the application of NASA Earth observations from 2014 to 2023 to detect changes in forest phenology possibly related to DED. Landsat 8 and 9 imagery was used to calculate multiyear time series of the Normalized Difference Vegetation Index (NDVI) and quantify changes in land surface phenology for a given year. A pixel-based logistic regression analysis was performed using changes in NDVI, tree site locations, and recorded occurrences of trees infected with DED as inputs. The results of this analysis show that changes in NDVI derived from Landsat data are capable of detecting unhealthy tree canopies with 71% precision and healthy tree canopies with 41% precision. The study had uncertainties and limitations due to the spatial and temporal resolutions of Landsat, the natural variability in land surface phenology and NDVI, and the attempt to detect disease impacts while disease prevention and mitigation is occurring. As is, the findings of this study and its methods provide managers with an approach for integrating Earth observations to make more informed decisions in the application and timing of urban forest management activities.

Central Park↗
DOE OSTI2018

Mosaic conserved region HIV immunogenic polypeptides

Disclosed herein are mosaic conserved region HIV polypeptides and immunogenic polypeptides including one or more of the mosaic conserved region polypeptides. In some embodiments, the immunogenic polypeptides are included in an immunogenic composition, such as a polyvalent immunogenic composition. Also disclosed herein are methods for treating or inhibiting HIV in a subject including administering one or more of the disclosed immunogenic polypeptides or compositions to a subject having or at risk of HIV infection. In some embodiments, the methods include inducing an immune response in a subject comprising administering to the subject at least one of the disclosed immunogenic polypeptides or a nucleic acid encoding at least one of the immunogenic polypeptides.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Nucleic acids encoding mosaic conserved region HIV immunogenic polypeptides

Disclosed herein are mosaic conserved region HIV polypeptides and immunogenic polypeptides including one or more of the mosaic conserved region polypeptides. In some embodiments, the immunogenic polypeptides are included in an immunogenic composition, such as a polyvalent immunogenic composition. Also disclosed herein are methods for treating or inhibiting HIV in a subject including administering one or more of the disclosed immunogenic polypeptides or compositions to a subject having or at risk of HIV infection. In some embodiments, the methods include inducing an immune response in a subject comprising administering to the subject at least one of the disclosed immunogenic polypeptides or a nucleic acid encoding at least one of the immunogenic polypeptides.

Korber, Bette T. M.↗
DOE OSTI2023

Conservation of Helium while Maintaining High System Purity

Recent helium shortages and helium price increases have lead to an increased emphasis being placed on conserving helium. The need to conserve helium must be balanced with need to maintain the high levels of purity necessary to prevent operational problems caused by contamination. Helium losses and contamination control are especially important for test stands that have cryogenic distribution systems operating continuously with frequent changeover of cryogenic temperature components that are being tested. This paper describes a mathematical model to estimate the quantity of helium lost and the purity of the helium after the pump and backfill procedure is complete. The process to determine the optimal time during pump down to cut off pumping and start backfilling is described. There is a tradeoff between trying to achieve the lowest possible pressure during pumping and the quantity of air leaking into the volume while pumping is occurring. An additional benefit of careful selection of pump and backfill parameters in conjunction with real-time pressure monitoring can reduce the labor and time required to complete a successful pump and backfill procedure. This paper is intended to be a tool for engineers to review their pump and backfill procedures and measured data to optimize helium losses, system purity, and labor required.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

A multi-dimensional, energy- and charge-conserving, nonlinearly implicit, electromagnetic Vlasov–Darwin particle-in-cell algorithm

For decades, the Vlasov–Darwin model has been recognized to be attractive for particle-in-cell (PIC) kinetic plasma simulations in non-radiative electromagnetic regimes, to avoid radiative noise issues and gain computational efficiency. However, the Darwin model results in an elliptic set of field equations that renders conventional explicit time integration unconditionally unstable. We explore a fully implicit PIC algorithm for the Vlasov–Darwin model in multiple dimensions, which overcomes many difficulties of traditional semi-implicit Darwin PIC algorithms. The finite-difference scheme for Darwin field equations and particle equations of motion is space–time-centered, employing particle sub-cycling and orbit-averaging. This algorithm conserves total energy, local charge, canonical-momentum in the ignorable direction, and preserves the Coulomb gauge exactly. An asymptotically well-posed fluid preconditioner allows efficient use of large cell sizes, which are determined by accuracy considerations, not stability, and can be orders of magnitude larger than required in a standard explicit electromagnetic PIC simulation. Finally, we demonstrate the accuracy and efficiency properties of the algorithm with various numerical experiments in 2D–3V.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Harvest and nitrogen effects on bioenergy feedstock quality of grass-legume mixtures on Conservation Reserve Program grasslands

Perennial grass mixtures established on Conservation Reserve Program (CRP) lands can be an important source of feedstock for bioenergy production. This study aimed to evaluate management practices for optimizing the quality of bioenergy feedstock and stand persistence of grass-legume mixtures under diverse environments. A 5-year field study (2008–2012) was conducted to assess the effects of two harvest timings (at anthesis vs after complete senescence) and three nitrogen (N) rates (0, 56, 112 kg N ha -1 ) on biomass chemical compositions (i.e., cell wall components, ash, volatiles, total carbon, and N contents) and the feedstock energy potential, examined by the theoretical ethanol yield (TEY) and the total TEY (i.e., the product of biomass yield and TEY, L ha -1 ), of cool-season mixtures in Georgia and Missouri and a warm-season mixture in Kansas. The canonical correlation analysis (CCA) was used to investigate the effect of vegetative species transitions on feedstock quality. Although environmental variations (mainly precipitation) greatly influenced the management effect on chemical compositions, the delayed harvest after senescence generally improved feedstock quality. In particular, the overall cell wall concentrations and TEY of the warm-season mixtures increased by approximately 7%. Additional N supplies improved the total TEY of both mixtures by ~1.6–4.2 L ha -1 per 1.0 kg N ha -1 input but likely lowered the feedstock quality, particularly for the cool-season mixture. The cell wall concentrations of cool-season mixture reduced by approximately 3%–6%. The CCA results indicated that the increased legume compositions (under low N input) likely enhanced lignin but reduced ash concentrations. This field research demonstrated that with proper management, grass-legume mixtures on CRP lands can provide high-quality feedstock for bioenergy productions.

09 BIOMASS FUELS↗
DOE OSTI2017

A framework for quantifying the impact of occupant behavior on energy savings of energy conservation measures

To improve energy efficiency—during new buildings design or during a building retrofit—evaluating the energy savings potential of energy conservation measures (ECMs) is a critical task. In building retrofits, occupant behavior significantly impacts building energy use and is a leading factor in uncertainty when determining the effectiveness of retrofit ECMs. Current simulation-based assessment methods simplify the representation of occupant behavior by using a standard or representative set of static and homogeneous assumptions ignoring the dynamics, stochastics, and diversity of occupant's energy-related behavior in buildings. The simplification contributes to significant gaps between the simulated and measured actual energy performance of buildings. This paper presents a framework for quantifying the impact of occupant behaviors on ECM energy savings using building performance simulation. During the first step of the study, three occupant behavior styles (austerity, normal, and wasteful) were defined to represent different levels of energy consciousness of occupants regarding their interactions with building energy systems (HVAC, windows, lights and plug-in equipment). Next, a simulation workflow was introduced to determine a range of the ECM energy savings. Then, guidance was provided to interpret the range of ECM savings to support ECM decision making. Finally, a pilot study was performed in a real building to demonstrate the application of the framework. Simulation results show that the impact of occupant behaviors on ECM savings vary with the type of ECM. Occupant behavior minimally affects energy savings for ECMs that are technology-driven (the relative savings differ by less than 2%) and have little interaction with the occupants; for ECMs with strong occupant interaction, such as the use of zonal control variable refrigerant flow system and natural ventilation, energy savings are significantly affected by occupant behavior (the relative savings differ by up to 20%). Finally, the study framework provides a novel, holistic approach to assessing the uncertainty of ECM energy savings related to occupant behavior, enabling stakeholders to understand and assess the risk of adopting energy efficiency technologies for new and existing buildings.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

An implicit, conservative and asymptotic-preserving electrostatic particle-in-cell algorithm for arbitrarily magnetized plasmas in uniform magnetic fields

Here, we introduce a new electrostatic particle-in-cell algorithm capable of using large timesteps compared to particle gyro-period under a uniform external magnetic field. The algorithm extends earlier electrostatic fully implicit PIC implementations with a new asymptotic-preserving particle-push scheme that allows timesteps much larger than particle gyroperiods. In the large-timestep limit, the integrator preserves all particle drifts, while recovering the full orbit for small timesteps. The scheme allows for a seamless, efficient treatment of particles with coexisting magnetized and unmagnetized species, and conserves energy and charge exactly without spoiling implicit solver performance. We demonstrate by numerical experiment with several problems of variable species magnetization (diocotron instability, modified two-stream instability, and drift instability) that orders of magnitude wall-clock-time speedups vs. the standard fully implicit electrostatic PIC algorithm are possible without sacrificing solution accuracy.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

U.S. Department of Energy Energy Efficiency Conservation Block Grant (Better Buildings Neighborhood Program Report) [Slides]

The Wisconsin Energy Efficiency (WE2) Program delivered residential and commercial programming for the City of Milwaukee (Me2) and the City of Madison (Green Madison) as well as commercial only programming for the City of Racine (Re2). Direct incentives and loan products for homeowners and business owners were offered, with the goal to achieve at least 15 percent in energy savings. At the time of this report, there were more than 2,000 residential energy efficiency upgrades completed and more than 300 commercial energy efficiency upgrades completed. The average energy savings for the WE2 Program’s portfolio of residential and commercial projects exceeds 15 percent and is closer to 30 percent energy savings. Combined energy savings of both residential and commercial activities were: 20,937,369 kWh; 1,018,907 Therms; and 31,655 gallons of heating oil; or at least 332,788 MMBTUs; or at least $\$3,444,828$ in estimated energy costs saved. Conservative economic impact estimates include the employment of more than 100 residential auditors and contractors, more than 90 commercial contractors, and more than $\$41$ million in total project costs expended in the targeted communities.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2014

Resource Conservation and a Sustainable Las Vegas

This research project developed educational, research, and outreach activities that addressed the challenges of Las Vegas as related to a secure energy supply through conservation, clean and adequate water supply, economic growth and diversification, air quality, and the best use of land, and usable public places. This was part of the UNLV Urban Sustainability Initiative (USI) that responded to a community and state need where a unifying vision of sustainability was developed in a cost-effective manner that promoted formal working partnerships between government, community groups, and industry.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Federal Government Energy Management and Conservation Programs (Fiscal Year 2008)

Annual reports on Federal energy management respond to section 548 of the National Energy Conservation Policy Act (NECPA, Pub. L. No. 95-619), as amended, and provide information on energy consumption in Federal buildings, operations, and vehicles. Compiled by the Federal Energy Management Program, these reports document activities conducted by Federal agencies under the: Energy management and energy consumption requirements of section 543 of NECPA, as amended (42 U.S.C. § 8253); Energy savings performance contract authority of section 801 of NECPA, Pub. L. No. 95-619, as amended (42 U.S.C. §§ 8287-8287d); Renewable energy purchase goal of section 203 of the Energy Policy Act (EPAct) of 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 15852); Federal building performance standard requirements under Section 109 of EPAct 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 6834(a)); Requirements on the procurement and identification of energy efficient products under section 161 of EPAct 1992, Pub. L. No. 102-486 (codified at 42 U.S.C. § 8262g); Sections 431, 432, and 434 of the Energy Independence and Security Act of 2007 (EISA), Pub. L. No. 110-140 (42 U.S.C. § 8253) and section 527 of EISA (42 U.S.C. § 17143); Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation Management, 72 Fed. Reg. 3,919 (Jan. 26, 2007); Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance, 74 Fed. Reg. 52,117 (Oct. 5, 2009).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Annual Report on Federal Government Energy Management and Conservation Programs (Fiscal Year 2010)

Annual reports on Federal energy management respond to section 548 of the National Energy Conservation Policy Act (NECPA, Pub. L. No. 95-619), as amended, and provide information on energy consumption in Federal buildings, operations, and vehicles. Compiled by the Federal Energy Management Program, these reports document activities conducted by Federal agencies under the: Energy management and energy consumption requirements of section 543 of NECPA, as amended (42 U.S.C. § 8253); Energy savings performance contract authority of section 801 of NECPA, Pub. L. No. 95-619, as amended (42 U.S.C. §§ 8287-8287d); Renewable energy purchase goal of section 203 of the Energy Policy Act (EPAct) of 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 15852); Federal building performance standard requirements under Section 109 of EPAct 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 6834(a)); Requirements on the procurement and identification of energy efficient products under section 161 of EPAct 1992, Pub. L. No. 102-486 (codified at 42 U.S.C. § 8262g); Sections 431, 432, and 434 of the Energy Independence and Security Act of 2007 (EISA), Pub. L. No. 110-140 (42 U.S.C. § 8253) and section 527 of EISA (42 U.S.C. § 17143); Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation Management, 72 Fed. Reg. 3,919 (Jan. 26, 2007); Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance, 74 Fed. Reg. 52,117 (Oct. 5, 2009).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Annual Report on Federal Government Energy Management and Conservation Programs (Fiscal Year 2011)

Annual reports on Federal energy management respond to section 548 of the National Energy Conservation Policy Act (NECPA, Pub. L. No. 95-619), as amended, and provide information on energy consumption in Federal buildings, operations, and vehicles. Compiled by the Federal Energy Management Program, these reports document activities conducted by Federal agencies under the: Energy management and energy consumption requirements of section 543 of NECPA, as amended (42 U.S.C. § 8253); Energy savings performance contract authority of section 801 of NECPA, Pub. L. No. 95-619, as amended (42 U.S.C. §§ 8287-8287d); Renewable energy purchase goal of section 203 of the Energy Policy Act (EPAct) of 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 15852); Federal building performance standard requirements under Section 109 of EPAct 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 6834(a)); Requirements on the procurement and identification of energy efficient products under section 161 of EPAct 1992, Pub. L. No. 102-486 (codified at 42 U.S.C. § 8262g); Sections 431, 432, and 434 of the Energy Independence and Security Act of 2007 (EISA), Pub. L. No. 110-140 (42 U.S.C. § 8253) and section 527 of EISA (42 U.S.C. § 17143); Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation Management, 72 Fed. Reg. 3,919 (Jan. 26, 2007); Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance, 74 Fed. Reg. 52,117 (Oct. 5, 2009).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Annual Report on Federal Government Energy Management and Conservation Programs (Fiscal Year 2012)

Annual reports on Federal energy management respond to section 548 of the National Energy Conservation Policy Act (NECPA, Pub. L. No. 95-619), as amended, and provide information on energy consumption in Federal buildings, operations, and vehicles. Compiled by the Federal Energy Management Program, these reports document activities conducted by Federal agencies under the: Energy management and energy consumption requirements of section 543 of NECPA, as amended (42 U.S.C. § 8253); Energy savings performance contract authority of section 801 of NECPA, Pub. L. No. 95-619, as amended (42 U.S.C. §§ 8287-8287d); Renewable energy purchase goal of section 203 of the Energy Policy Act (EPAct) of 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 15852); Federal building performance standard requirements under Section 109 of EPAct 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 6834(a)); Requirements on the procurement and identification of energy efficient products under section 161 of EPAct 1992, Pub. L. No. 102-486 (codified at 42 U.S.C. § 8262g); Sections 431, 432, and 434 of the Energy Independence and Security Act of 2007 (EISA), Pub. L. No. 110-140 (42 U.S.C. § 8253) and section 527 of EISA (42 U.S.C. § 17143); Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation Management, 72 Fed. Reg. 3,919 (Jan. 26, 2007); Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance, 74 Fed. Reg. 52,117 (Oct. 5, 2009).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Annual Report on Federal Government Energy Management and Conservation Programs (Fiscal Year 2013)

Annual reports on Federal energy management respond to section 548 of the National Energy Conservation Policy Act (NECPA, Pub. L. No. 95-619), as amended, and provide information on energy consumption in Federal buildings, operations, and vehicles. Compiled by the Federal Energy Management Program, these reports document activities conducted by Federal agencies under the: Energy management and energy consumption requirements of section 543 of NECPA, as amended (42 U.S.C. § 8253); Energy savings performance contract authority of section 801 of NECPA, Pub. L. No. 95-619, as amended (42 U.S.C. §§ 8287-8287d); Renewable energy purchase goal of section 203 of the Energy Policy Act (EPAct) of 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 15852); Federal building performance standard requirements under Section 109 of EPAct 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 6834(a)); Requirements on the procurement and identification of energy efficient products under section 161 of EPAct 1992, Pub. L. No. 102-486 (codified at 42 U.S.C. § 8262g); Sections 431, 432, and 434 of the Energy Independence and Security Act of 2007 (EISA), Pub. L. No. 110-140 (42 U.S.C. § 8253) and section 527 of EISA (42 U.S.C. § 17143); Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation Management, 72 Fed. Reg. 3,919 (Jan. 26, 2007); Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance, 74 Fed. Reg. 52,117 (Oct. 5, 2009).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Federal Government Energy Management and Conservation Programs (Fiscal Year 2009)

Annual reports on Federal energy management respond to section 548 of the National Energy Conservation Policy Act (NECPA, Pub. L. No. 95-619), as amended, and provide information on energy consumption in Federal buildings, operations, and vehicles. Compiled by the Federal Energy Management Program, these reports document activities conducted by Federal agencies under the: Energy management and energy consumption requirements of section 543 of NECPA, as amended (42 U.S.C. § 8253); Energy savings performance contract authority of section 801 of NECPA, Pub. L. No. 95-619, as amended (42 U.S.C. §§ 8287-8287d); Renewable energy purchase goal of section 203 of the Energy Policy Act (EPAct) of 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 15852); Federal building performance standard requirements under Section 109 of EPAct 2005, Pub. L. No. 109-58 (codified at 42 U.S.C. § 6834(a)); Requirements on the procurement and identification of energy efficient products under section 161 of EPAct 1992, Pub. L. No. 102-486 (codified at 42 U.S.C. § 8262g); Sections 431, 432, and 434 of the Energy Independence and Security Act of 2007 (EISA), Pub. L. No. 110-140 (42 U.S.C. § 8253) and section 527 of EISA (42 U.S.C. § 17143); Executive Order 13423, Strengthening Federal Environmental, Energy, and Transportation Management, 72 Fed. Reg. 3,919 (Jan. 26, 2007); Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance, 74 Fed. Reg. 52,117 (Oct. 5, 2009).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2017

Electron Bifurcation Makes the Puzzle Pieces Fall Energetically into Place in Methanogenic Energy Conservation

Microbial life has evolved a wide range of metabolisms exploiting in many cases unanticipated suites of oxidation-reduction reactions to generate energy. Although many of these suites of reactions don't allow these microbes to enjoy the same quality of energetic life that we enjoy via respiration/oxidative phosphorylation, it has conferred the ability for life to exploit almost any oxidation-reduction reaction. We find in many of these cases when energy is sparing, the difference between life and death may be conserving the maximal amount of energy and minimizing loss of free energy through heat.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Error estimates to smooth solutions of semi-discrete discontinuous Galerkin methods with quadrature rules for scalar conservation laws

Here, we focus on error estimates to smooth solutions of semi-discrete discontinuous Galerkin (DG) methods with quadrature rules for scalar conservation laws. The main techniques we use are energy estimate and Taylor expansion first introduced by Zhang and Shu in (Zhang and Shu, SIAM J Num Anal 42 (2004), 641–666). We show that, with p K (piecewise polynomials of degree k) finite elements in 1D problems, if the quadrature over elements is exact for polynomials of degree (2k) error estimates of O(h k+1/2 ) are obtained for general monotone fluxes, and optimal estimates of O(h k+1 ) are obtained for upwind fluxes. For multidimensional problems, if in addition quadrature over edges is exact for polynomials of degree (2k+1), error estimates of O(h k ) are obtained for general monotone fluxes, and O(h k+1/2 ) are obtained for monotone and sufficiently smooth numerical fluxes. Numerical results validate our analysis.

97 MATHEMATICS AND COMPUTING↗