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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Assess The Water Resistance And Thermal Performance Of Pre-flashing Methods When Adding Continuous Insulation During Re-siding (AIRS)

Retrofitting existing buildings by adding continuous insulation during re-siding projects has become a popular method for enhancing energy efficiency, especially given the aging building stock and stricter energy codes. When properly integrated with existing window systems, continuous insulation can significantly improve thermal performance, but it also presents challenges related to water resistance and building envelope integrity. Research indicates that the interface between windows and wall assemblies is critical as improper installation or sealing can lead to water intrusion, materials deterioration, and energy loss. Moreover, studies show that fully integrating the windows with the insulation layer can reduce window heat loss by up to 40%, emphasizing the importance of optimizing window placement and sealing during retrofitting to ensure both energy efficiency and structural performance. In this study, we conducted experimental tests to evaluate the water penetration and thermal performance of two window types: an aluminum window with a 2-inch installation fin and a wood window, representing typical mid-20th century designs. Using the Heat, Air, and Humidity (HAM) chamber at Oak Ridge National Laboratory (ORNL), we assessed bulk water penetration and performed COMSOL analysis for thermal flux and examined the effectiveness of different pre-flashing methods, i.e., standard self-adhered flashing tape and high-performance flashing tape with low-expansion foam, to enhance water resistance. The results indicate that applying proper flashing techniques and moisture management strategies can mitigate these risks, improving the overall performance and durability of retrofitted buildings. Additionally, proper sealing during retrofitting is essential, as improper installation can lead to moisture issues that compromise both energy efficiency and structural integrity.

Shen, Zhenglai [ORNL]↗
NASA NTRS1992

Studies on penetration of antibiotic in bacterial cells in space conditions (7-IML-1)

The Cytos 2 experiment was performed aboard Salyut 7 in order to test the antibiotic sensitivity of bacteria cultivated in vitro in space. An increase of the Minimal Inhibitory Concentration (MIC) in the inflight cultures (i.e., an increase of the antibiotic resistance) was observed. Complementary studies of the ultrastructure showed a thickening of the cell envelope. In order to confirm the results of the Cytos 2 experiment, we performed the ANTIBIO experiment during the D1 mission to try to differentiate, by means of the 1 g centrifuge in the Biorack, between the biological effects of cosmic rays and those caused by microgravity conditions. The originality of this experiment was in the fact that it was designed to test the antibiotic sensitivity of bacteria cultivated in vitro during the orbital phase of the flight. The results show an increase in resistance to Colistin in in-flight bacteria. The MIC is practically double in the in-flight cultures. A cell count of living bacteria in the cultures containing the different Colistin concentrations showed a significant difference between the cultures developed during space flight and the ground based cultures. The comparison between the 1 g and 0 g in-flight cultures show similar behavior for the two sets. Nevertheless, a small difference between the two sets of ground based control cultures was noted. The cultures developed on the ground centrifuge (1.4 g) present a slight decrease in comparison with the cultures developed in the static rack (1 g). In order to approach the mechanisms of the increase of antibiotic resistance on bacteria cultivated in vitro in space, we have proposed the study on penetration of antibiotics in bacterial cells in space conditions. This experiment was selected for the International Microgravity Laboratory 1 (IML-1) mission.

Tixador, R.↗
DOE OSTI2020

Band-edge Engineering to Eliminate Radiation-Induced Defect States in Perovskite Scintillators

Under radiative environments such as extended hard X- or γ-rays, degradation of scintillation performance is often due to irradiation-induced defects. To overcome the effect of deleterious defects, novel design mitigation strategies are needed to identify and design more resilient materials. The potential for band-edge engineering to eliminate the effect of radiation-induced defect states in rare-earth-doped perovskite scintillators is explored, taking Ce 3+ -doped LuAlO 3 as a model material system, using density functional theory (DFT)-based DFT + U and hybrid Heyd–Scuseria–Ernzerhof (HSE) calculations. Furthermore, from spin-polarized hybrid HSE calculations, the Ce 3+ activator ground-state 4f position is determined to be 2.81 eV above the valence band maximum in LuAlO 3 . Except for the oxygen vacancies which have a deep level inside the band gap, all other radiation-induced defects in LuAlO 3 have shallow defect states or are outside the band gap, that is, relatively far away from either the 5d 1 or the 4f Ce 3+ levels. Finally, we examine the role of Ga doping at the Al site and found that LuGaO 3 has a band gap that is more than 2 eV smaller than that of LuAlO 3 . Specifically, the lowered conduction band edge envelopes the defect gap states, eliminating their potential impact on scintillation performance and providing direct theoretical evidence for how band-edge engineering could be applied to rare-earth-doped perovskite scintillators.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Technology Solutions Case Study: Predicting Envelope Leakage in Attached Dwellings

The most common method of measuring air leakage is to perform single (or solo) blower door pressurization and/or depressurization test. In detached housing, the single blower door test measures leakage to the outside. In attached housing, however, this “solo” test method measures both air leakage to the outside and air leakage between adjacent units through common surfaces. In an attempt to create a simplified tool for predicting leakage to the outside, Building America team Consortium for Advanced Residential Buildings (CARB) performed a preliminary statistical analysis on blower door test results from 112 attached dwelling units in four apartment complexes. Although the subject data set is limited in size and variety, the preliminary analyses suggest significant predictors are present and support the development of a predictive model. Further data collection is underway to create a more robust prediction tool for use across different construction types, climate zones, and unit configurations.

algorithm↗
NASA NTRS1989

High performance linear-quadratic and H-infinity designs for a 'supermaneuverable' aircraft

Recent efforts by the National Aeronautics and Space Administration Langley Research Center have focused on expanding the flight envelope of the F/A-18 aircraft. Of particular concern has been the low speed, high angle-of-attack regime over which the conventional aerodynamic controls of the F/A-18 lose their effectiveness. In order to address this problem the F18 high alpha research vehicle was developed. This aircraft is essentially a modified F/A-18 which possesses thrust vectoring capabilities and hence increased maneuverability in this flight regime. The linear-quadratic-Gaussian with loop-transfer-recovery and H(infinity) design methodologies are used to design high performance controllers for the F18 at an operating point within the expanded envelope. In addition, how the control redundancy of the F18 can be used to maintain nominal performance, as well as nominal stability, in situations where failures occur, is shown.

Voulgaris, Petros↗
NASA NTRS1989

Performance and loads data from an outdoor hover test of a Lynx tail rotor

A Lynx tail rotor was tested in hover at the Outdoor Aerodynamic Research Facility at NASA Ames Research Center. The test objectives were to measure the isolated rotor performance to provide a baseline for subsequent testing, and to operate the rotor throughout the speed and collective envelope before testing in the NFAC 40- by 80-Foot Wind Tunnel. Rotor forces and blade bending moments were measured at ambient wind conditions from zero to 6.23 m/sec. The test envelope was limited to rotor speeds of 1550 to 1850 rpm and minus 13 deg to plus 20 deg of blade collective pitch. The isolated rotor performance and blade loads data are presented.

Signor, David B.↗
DOE OSTI2015

Building America Case Study: High Performance Ducts in Hot-Dry Climates; Technology Solutions for New and Existing Homes, Energy Efficiency & Renewable Energy (EERE)

?Ducts in conditioned space (DCS) represent a high priority measure for moving the next generation of new homes to the Zero Net Energy performance level. Various strategies exist for incorporating ducts within the conditioned thermal envelope. To support this activity, in 2013 the Pacific Gas & Electric Company initiated a project with Davis Energy Group (lead for the Building America team, Alliance for Residential Building Innovation) to solicit builder involvement in California to participate in field demonstrations of various DCS strategies. Builders were given incentives and design support in exchange for providing site access for construction observation, diagnostic testing, and builder survey feedback. Information from the project was designed to feed into California's 2016 Title 24 process, but also to serve as an initial mechanism to engage builders in more high performance construction strategies. This Building America project complemented information collected in the California project with BEopt simulations of DCS performance in hot/dry climate regions.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Technology Solutions Case Study: High-Performance Ducts in Hot-Dry Climates

Ducts in conditioned space (DCS) represent a high priority measure for moving the next generation of new homes to the Zero Net Energy performance level. Various strategies exist for incorporating ducts within the conditioned thermal envelope. To support this activity, in 2013 the Pacific Gas & Electric Company initiated a project with Davis Energy Group (lead for the Building America team, Alliance for Residential Building Innovation) to solicit builder involvement in California to participate in field demonstrations of various DCS strategies. Builders were given incentives and design support in exchange for providing site access for construction observation, diagnostic testing, and builder survey feedback. Information from the project was designed to feed into California's 2016 Title 24 process, but also to serve as an initial mechanism to engage builders in more high performance construction strategies. This Building America project complemented information collected in the California project with BEopt simulations of DCS performance in hot/dry climate regions.

ARBI↗
DOE OSTI2023

Performance assessment of active insulation systems in residential buildings for energy savings and peak demand reduction

Active insulation systems (AISs) in buildings are envelopes that integrate thermal insulation, thermal energy storage, and controls. Although different designs for AISs have been proposed in the literature, a comprehensive analysis of feasible AISs is lacking. This paper discusses the energy performance, peak demand reduction potential, and performance characteristics of an AIS that uses a concrete wall as thermal mass sandwiched between two solid-state thermal switches (STSs). These STSs change their thermal conductivity using an on/off metal switch to create or break a thermal bridge across the STS. This paper first describes the experimental setup, used to determine the ratio of thermal resistance during R-high (low thermal conductivity) and R-low (high thermal conductivity) states of the STSs. This ratio was then used in whole-building energy simulations to evaluate the performance of AIS walls across different climate zones with/without a freeze timer of 60 min. The timer was added to reduce the number of switches of STSs from one state to another, and hence the energy needed for these switches. Analysis of the switching frequency and interval of STSs, thermal conductivity of walls, impact of wall orientation, and heat transfer through the wall from the use of AIS at different climate zones/locations were performed. The simulation results show that the AIS can achieve energy savings ranging from ~980 to 2,290 kWh in a single-family home with a floor area of ~220 m 2 compared with an IECC 2018 baseline. We found the energy savings was higher in dry climate zones which represent 17% of residential buildings in the United States, compared to humid or marine climate.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1983

Split-Stirling-cycle displacer linear-electric drive

The retrofit of a 1/4-W split-Stirling cooler with a linear driven on the displacer was achieved and its performance characterized. The objective of this work was to demonstrate that a small linear motor could be designed to meet the existing envelope specifications of the cooler and that an electric linear drive on the displacer could improve the cooler's reliability and performance. The paper describes the characteristics of this motor and presents cooler test results.

Ackermann, R. A.↗
DOE OSTI2015

Climate-Specific Passive Building Standards

In 2012, the U.S. Department of Energy (DOE) recognized the value of performance-based passive building standards when it joined with Passive House Institute US (PHIUS) to promote DOE’s Challenge Home program in tandem with the PHIUS+ Certification program. Since then, the number of passive building projects that have been certified under the partnership has grown exponentially because of some synergy. Passive building represents a well-developed approach to arrive at the envelope basis for zero energy and energy-positive projects by employing performance-based criteria and maximizing cost-effective savings from conservation before implementing renewable energy technologies. The Challenge Home program evolved into the Zero Energy Ready Home (ZERH) program in a move toward 1) attaining zero energy and 2) including active renewable energy generation such as photovoltaics (PV)—toward the zero energy goal.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2026

Optics reconstruction in the SCL section of the FNAL Linac

The Side-Coupled Linac (SCL) section of the FNAL linac accelerates the beam from 116 MeV to 401.5 MeV, operating at 22-24 mA beam current. Transverse focusing is performed by 32 quadrupoles, and the beam orbit is guided by 19 dipole correctors and measured by 29 BPMs. The bunch length is measured in a single location by a Bunch Shape Monitor (BSM). This paper presents a three-step reconstruction of the machine optics. First, the transverse and longitudinal Twiss parameters at the start of the SCL section are determined using quadrupole scans and BSM measurements at different settings of an upstream cavity. Second, the quadrupole calibrations are adjusted based on differential-trajectory measurements. Finally, the beam is propagated along the SCL linac using the code TraceWin. A comparison between TraceWin simulations and the beam envelope measured by the 12 wire scanners of the SCL linac was performed. Transverse and longitudinal beam parameters at the entrance and exit of the SCL section will be reported.

Carneiro, Jean-Paul [Fermilab]↗
DOE OSTI2015

CALIBRATION OF THE MIXING-LENGTH THEORY FOR CONVECTIVE WHITE DWARF ENVELOPES

A calibration of the mixing-length parameter in the local mixing-length theory (MLT) is presented for the lower part of the convection zone in pure-hydrogen-atmosphere white dwarfs. The parameterization is performed from a comparison of three-dimensional (3D) CO5BOLD simulations with a grid of one-dimensional (1D) envelopes with a varying mixing-length parameter. In many instances, the 3D simulations are restricted to the upper part of the convection zone. The hydrodynamical calculations suggest, in those cases, that the entropy of the upflows does not change significantly from the bottom of the convection zone to regions immediately below the photosphere. We rely on this asymptotic entropy value, characteristic of the deep and adiabatically stratified layers, to calibrate 1D envelopes. The calibration encompasses the convective hydrogen-line (DA) white dwarfs in the effective temperature range 6000 ≤ T {sub eff} (K) ≤15, 000 and the surface gravity range 7.0 ≤ log g ≤ 9.0. It is established that the local MLT is unable to reproduce simultaneously the thermodynamical, flux, and dynamical properties of the 3D simulations. We therefore propose three different parameterizations for these quantities. The resulting calibration can be applied to structure and envelope calculations, in particular for pulsation, chemical diffusion, and convective mixing studies. On the other hand, convection has no effect on the white dwarf cooling rates until there is a convective coupling with the degenerate core below T {sub eff} ∼ 5000 K. In this regime, the 1D structures are insensitive to the MLT parameterization and converge to the mean 3D results, hence they remain fully appropriate for age determinations.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

$\mathrm{REX}$: An analytical tool for reactor operating envelope expansion through fuel-clad thermo-mechanics

Here REX, an analytical reactor design tool for the identification and expansion of reactor operating envelopes, is introduced and detailed. Written in MATLAB, REX takes core geometries and axially discretized detector and depletion output from the Serpent neutron transport code and performs full-core, pin-specific thermal-hydraulic and thermo-mechanical calculations. REX identifies the operating envelopes of advanced, solid-fuel nuclear reactors on the basis of their fuel-cladding, fuel-gas, and coolant-cladding interfacial thermo-mechanics. It iteratively pushes coolant inlet temperatures and modifies fuel pin geometries to induce mechanical failure in their original cladding materials at the fullest extent of their fuel cycle lengths and permissible coolant inlet temperatures. It then attempts to expand their operating envelopes by determining the mechanical responses of alternative cladding materials under the same geometric conditions. The result of the REX calculation sequence is a set of 5-D variables describing the temperatures, pressures, geometries, and mechanics of the core as functions of assembly, fuel pin, axial zone, depletion step, and coolant inlet temperature for each candidate cladding material with the limiting fuel pin geometry for the original material.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS2003

Performance of the Star Tracker Lightshades on the Earth Observing Satellite (EOS) Aqua

The TRW built EOS Aqua spacecraft uses two Ball Aerospace CT-602 star trackers to provide attitude updates to the 3-axis, zero momentum, controller. Two months prior to the scheduled launch of Aqua, Ball reported an error in the design of the star tracker lightshades. The lightshades, which had been designed specifically for the EOS Common spacecraft, were not expected to meet the stray light rejection requirements of the mission, thus impacting the overall spacecraft pointing performance. What ensued was an effort to characterize the actual performance of the existing shade design, determine what could be done within the physical envelope available, and modify the hardware to meet requirements. Changes were made based on this review activity and Aqua was launched on May 4, 2002. To date the spacecraft is meeting all of its science pointing requirements. Reported here are the lightshade design predictions, test results, and the measured on orbit performance of these shades.

Kenny, Thomas↗
NASA NTRS2003

Performance of the Star Tracker Lightshades on the Earth Observing Satellite (EOS) Aqua

The TRW built EOS Aqua spacecraft uses two Ball Aerospace CT-602 star trackers to provide attitude updates to the 3-axis, zero momentum, controller. Two months prior to the scheduled launch of Aqua, Ball reported an error in the design of the star tracker lightshades. The lightshades, which had been designed specifically for the EOS Common spacecraft, were not expected to meet the stray light rejection requirements of the mission and thus impact the overall spacecraft pointing performance. What ensued was an effort to characterize the actual performance of the existing shade design, determine what could be done within the physical envelope available, and modify the hardware to meet requirements. Changes were made based on this review activity and Aqua was launched on May 4, 2002. To date the spacecraft is meeting all of its science pointing requirements. Reported here are the lightshade design predictions, test results, and the measured on orbit performance of these shades.

Kenney, Thomas↗
DOE OSTI2016

Computational modeling of latent-heat-storage in PCM modified interior plaster

The latent heat storage systems represent a promising way for decrease of buildings energy consumption with respect to the sustainable development principles of building industry. The presented paper is focused on the evaluation of the effect of PCM incorporation on thermal performance of cement-lime plasters. For basic characterization of the developed materials, matrix density, bulk density, and total open porosity are measured. Thermal conductivity is accessed by transient impulse method. DSC analysis is used for the identification of phase change temperature during the heating and cooling process. Using DSC data, the temperature dependent specific heat capacity is calculated. On the basis of the experiments performed, the supposed improvement of the energy efficiency of characteristic building envelope system where the designed plasters are likely to be used is evaluated by a computational analysis. Obtained experimental and computational results show a potential of PCM modified plasters for improvement of thermal stability of buildings and moderation of interior climate.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Evaluation of Ventilation Strategies in New Construction Multifamily Buildings

In multifamily buildings, particularly in the Northeast, exhaust ventilation strategies are the norm as a means of meeting both local exhaust and whole-unit mechanical ventilation rates. The issue of where the 'fresh' air is coming from is gaining significance as air-tightness standards for enclosures become more stringent, and the 'normal leakage paths through the building envelope' disappear. CARB researchers have found that the majority of high performance, new construction, multifamily housing in the Northeast use one of four general strategies for ventilation: continuous exhaust only with no designated supply or make-up air source, continuous exhaust with ducted make-up air to apartments, continuous exhaust with supply through a make-up air device integral to the unit HVAC, and continuous exhaust with supply through a passive inlet device, such as a trickle vent. Insufficient information is available to designers on how these various systems are best applied. Product performance data are based on laboratory tests, and the assumption is that products will perform similarly in the field. Proper application involves matching expected performance at expected building pressures, but there is no guarantee that those conditions will exist consistently in the finished building. This research effort, which included several weeks of building pressure monitoring, sought to provide field validation of system performance. The performance of four substantially different strategies for providing make-up air to apartments was evaluated.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗