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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Purpose, Design, and Analysis of the NSTX-U Centerstack Casing Lateral Support Shims

The National Spherical Torus Experiment Upgrade (NSTX-U) centerstack casing surrounds the central magnet core of NSTXU. It provides the inner vacuum boundary of the plasma chamber and supports the radially inboard plasma facing components lining the plasma chamber. The casing is supported like a cantilever, fixed at the lower flange by a connection to the TF Bundle through a G-10 ring. It is flexibly supported at the top by bellows, and insulated shims intended to react the largest part of the inventory of the disruption loads at the upper support, thereby protecting the upper and lower connections from excessive loads. A large part of the qualification of the casing and tiles requires addressing and quantifying disruption loads. These have been estimated based on extensions of the behavior of NSTX during its run period roughly 15 years ago. Structural qualification of the Upgrade used these estimates of the loading as input to calculations to demonstrate adequacy for a “most probable” disruption. The estimates are included in a requirements document to guide conservative design of all components loaded by disruptions. However, the changes made for the upgrade made the extrapolation of disruption behavior uncertain. Disruptions include axisymmetric loading from axisymmetric currents induced in the vessel shells. In addition, more complex currents called Halo currents are a result of plasma poloidal currents impinging on the casing. The halo currents add another layer of uncertain behavior and net lateral loading to the casing. As a result, NSTX-U is equipped with a number of instruments intended to assess the nature and severity of disruptions. The casing shims are required for lateral support of the casing, but these have also been converted to load cells to provide another measure of the magnitude of symmetric and asymmetric loading. Some of the logic in the development of the requirements document are presented. Electromagnetic analysis of axisymmetric and halo loading is described. Global simulations of the casing transient dynamic response, and local analysis and testing of the shim/load cell are included. The shim load cells and other instrumentation will be an important guide in planning NSTX-U experiments beyond its next run period expected in late 2026 or early 2027.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Trends in Use of Hypofractionated Whole Breast Radiation in Breast Cancer: An Analysis of the National Cancer Database

Use of hypofractionated radiation (HR) as a component of breast-conserving treatment (BCT) in breast cancer is relatively low in the United States despite studies demonstrating its efficacy and guidelines supporting its use from the American Society for Radiation Oncology (ASTRO) in 2011 and 2018. Little is known regarding national trends in uptake and factors associated with uptake of HR in the US since the 2011 ASTRO guidelines.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Crystal structure of the conserved herpesvirus fusion regulator complex gH—gL

Herpesviruses, which cause many incurable diseases, infect cells by fusing viral and cellular membranes. Whereas most other enveloped viruses use a single viral catalyst called a fusogen, herpesviruses, inexplicably, require two conserved fusion-machinery components, gB and the heterodimer gH–gL, plus other nonconserved components. gB is a class III viral fusogen, but unlike other members of its class, it does not function alone. We determined the crystal structure of the gH ectodomain bound to gL from herpes simplex virus 2. gH–gL is an unusually tight complex with a unique architecture that, unexpectedly, does not resemble any known viral fusogen. Instead, we propose that gH–gL activates gB for fusion, possibly through direct binding. Formation of a gB–gH–gL complex is critical for fusion and is inhibited by a neutralizing antibody, making the gB–gH–gL interface a promising antiviral target.

Chowdary, Tirumala K.↗
DOE OSTI2019

Effect of backscattering on nonlinear distortions of the scale factor of a laser gyro with a rectangular bias

We report the results of measurements of nonlinear scale factor corrections, resulting from the backscattering effect in a laser gyro with a rectangular bias. It is shown that taking conservative and dissipative backscattering components into account allows one to obtain analytical relationships that adequately describe the frequency response of a laser gyroscope over the entire working range of angular velocities. Using these relationships to correct the frequency response of a laser gyroscope makes it possible to reduce the value of nonlinear corrections to 1 – 2 ppm. (laser gyroscopes)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2013

THE INTERACTING EARLY-TYPE BINARY V382 Cyg

We analyze photometric and spectroscopic data and study the orbital period of the early-type interacting binary system V382 Cyg by using all the available data. We obtain a simultaneous light and radial velocity curve solution. The derived physical parameters of the primary and secondary stellar components are M{sub 1} = 27.9(5) M{sub Sun }, M{sub 2} = 20.8(4) M{sub Sun }, R{sub 1} = 9.7(2) R{sub Sun }, R{sub 2} = 8.5(2) R{sub Sun }, log ({sub 1}/L{sub Sun }) = 5.152(20), and log (L{sub 2}/L{sub Sun }) = 4.954(19) while the separation of the components is a = 23.4 R{sub Sun }. Newly obtained parameters yield the distance of the system to be 1466(76) pc. Analyses of the mid-eclipse times indicate a period increase of dP/dt = 4.2(1) Multiplication-Sign 10{sup -7} days yr{sup -1} that can be interpreted in terms of the high-mass transfer (dM/dt 6.1(5) Multiplication-Sign 10{sup -6} M{sub Sun} yr{sup -1}) from the less massive component to the more massive component. Finally, we model the evolution of the components using non-conservative codes and discuss the results obtained. The age of the binary system is estimated to be 3.85 Myr.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1978

Review of JPL Automotive Technology Status and Projections (ATSP) project

The general objective was to make a continuing assessment of current automotive technology development programs and of the prospects for new concepts. The study embraced alternative engines, advanced powertrain components, and related energy conserving vehicle modifications which could be implemented by the end of this century. Vehicle level projections of the fuel economy and emissions potential of alternative power systems were key elements of this assessment.

Dowdy, M. W.↗
NASA NTRS1978

Automotive technology status and projections. Volume 2: Assessment report

Current and advanced conventional engines, advanced alternative engines, advanced power train components, and other energy conserving automobile modifications which could be implemented by the end of this century are examined. Topics covered include gas turbine engines, Stirling engines, advanced automatic transmissions, alternative fuels, and metal and ceramic technology. Critical problems are examined and areas for future research are indicated.

Dowdy, M.↗
NASA NTRS1977

Vibrational and rotational transitions in low-energy electron-diatomic-molecule collisions. I - Close-coupling theory in the moving body-fixed frame. II - Hybrid theory and close-coupling theory: An /l subscript z-prime/-conserving close-coupling approximation

A detailed vibrational-rotational (V-R) close-coupling formulation of electron-diatomic-molecule scattering is developed in which the target molecular axis is chosen to be the z-axis and the resulting coupled differential equation is solved in the moving body-fixed frame throughout the entire interaction region. The coupled differential equation and asymptotic boundary conditions in the body-fixed frame are given for each parity, and procedures are outlined for evaluating V-R transition cross sections on the basis of the body-fixed transition and reactance matrix elements. Conditions are discussed for obtaining identical results from the space-fixed and body-fixed formulations in the case where a finite truncated basis set is used. The hybrid theory of Chandra and Temkin (1976) is then reformulated, relevant expressions and formulas for the simultaneous V-R transitions of the hybrid theory are obtained in the same forms as those of the V-R close-coupling theory, and distorted-wave Born-approximation expressions for the cross sections of the hybrid theory are presented. A close-coupling approximation that conserves the internuclear axis component of the incident electronic angular momentum (l subscript z-prime) is derived from the V-R close-coupling formulation in the moving body-fixed frame.

Choi, B. H.↗
NASA NTRS1984

Estimating optimal sampling unit sizes for satellite surveys

This paper reports on an approach for minimizing data loads associated with satellite-acquired data, while improving the efficiency of global crop area estimates using remotely sensed, satellite-based data. Results of a sampling unit size investigation are given that include closed-form models for both nonsampling and sampling error variances. These models provide estimates of the sampling unit sizes that effect minimal costs. Earlier findings from foundational sampling unit size studies conducted by Mahalanobis, Jessen, Cochran, and others are utilized in modeling the sampling error variance as a function of sampling unit size. A conservative nonsampling error variance model is proposed that is realistic in the remote sensing environment where one is faced with numerous unknown nonsampling errors. This approach permits the sampling unit size selection in the global crop inventorying environment to be put on a more quantitative basis while conservatively guarding against expected component error variances.

Hallum, C. R.↗
NASA NTRS1988

Refractory metal alloys and composites for space nuclear power systems

Space power requirements for future NASA and other U.S. missions will range from a few kilowatts to megawatts of electricity. Maximum efficiency is a key goal of any power system in order to minimize weight and size so that the Space Shuttle may be used a minimum number of times to put the power supply into orbit. Nuclear power has been identified as the primary power source to meet these high levels of electrical demand. One method to achieve maximum efficiency is to operate the power supply, energy conservation system, and related components at relatively high temperatures. For systems now in the planning stages, design temperatures range from 1300 K for the immediate future to as high as 1700 K for the advanced systems. NASA Lewis Research Center has undertaken a research program on advanced technology of refractory metal alloys and composites that will provide baseline information for space power systems in the 1900's and the 21st century. Special emphasis is focused on the refractory metal alloys of niobium and on the refractory metal composites which utilize tungsten alloy wires for reinforcement. Basic research on the creep and creep-rupture properties of wires, matrices, and composites are discussed.

Titran, Robert H.↗
NASA NTRS1993

A direct current rectification scheme for microwave space power conversion using traveling wave electron acceleration

The formation of the Vision-21 conference held three years ago allowed the present author to reflect and speculate on the problem of converting electromagnetic energy to a direct current by essentially reversing the process used in traveling wave tubes that converts energy in the form of a direct current to electromagnetic energy. The idea was to use the electric field of the electromagnetic wave to produce electrons through the field emission process and accelerate these electrons by the same field to produce an electric current across a large potential difference. The acceleration process was that of cyclotron auto-resonance. Since that time, this rather speculative ideas has been developed into a method that shows great promise and for which a patent is pending and a prototype design will be demonstrated in a potential laser power beaming application. From the point of view of the author, a forum such as Vision-21 is becoming an essential component in the rather conservative climate in which our initiatives for space exploration are presently formed. Exchanges such as Vision-21 not only allows us to deviate from the 'by-the-book' approach and rediscover the ability and power in imagination, but provides for the discussion of ideas hitherto considered 'crazy' so that they may be given the change to transcend from the level of eccentricity to applicability.

Manning, Robert M.↗
NASA NTRS2005

Excitation of Earth Rotation Variations "Observed" by Time-Variable Gravity

Time variable gravity measurements have been made over the past two decades using the space geodetic technique of satellite laser ranging, and more recently by the GRACE satellite mission with improved spatial resolutions. The degree-2 harmonic components of the time-variable gravity contain important information about the Earth s length-of-day and polar motion excitation functions, in a way independent to the traditional "direct" Earth rotation measurements made by, for example, the very-long-baseline interferometry and GPS. In particular, the (degree=2, order= 1) components give the mass term of the polar motion excitation; the (2,O) component, under certain mass conservation conditions, gives the mass term of the length-of-day excitation. Combining these with yet another independent source of angular momentum estimation calculated from global geophysical fluid models (for example the atmospheric angular momentum, in both mass and motion terms), in principle can lead to new insights into the dynamics, particularly the role or the lack thereof of the cores, in the excitation processes of the Earth rotation variations.

Chao, Ben F.↗
NASA NTRS2010

Validation of a Three-Dimensional Ablation and Thermal Response Simulation Code

The 3dFIAT code simulates pyrolysis, ablation, and shape change of thermal protection materials and systems in three dimensions. The governing equations, which include energy conservation, a three-component decomposition model, and a surface energy balance, are solved with a moving grid system to simulate the shape change due to surface recession. This work is the first part of a code validation study for new capabilities that were added to 3dFIAT. These expanded capabilities include a multi-block moving grid system and an orthotropic thermal conductivity model. This paper focuses on conditions with minimal shape change in which the fluid/solid coupling is not necessary. Two groups of test cases of 3dFIAT analyses of Phenolic Impregnated Carbon Ablator in an arc-jet are presented. In the first group, axisymmetric iso-q shaped models are studied to check the accuracy of three-dimensional multi-block grid system. In the second group, similar models with various through-the-thickness conductivity directions are examined. In this group, the material thermal response is three-dimensional, because of the carbon fiber orientation. Predictions from 3dFIAT are presented and compared with arcjet test data. The 3dFIAT predictions agree very well with thermocouple data for both groups of test cases.

Chen, Yih-Kanq↗
DOE OSTI2020

Prefabricated Zero Energy Retrofit Technologies: A Market Assessment

Part of the U.S. Department of Energy's (DOE) Office of Energy Efficiency and Renewable Energy’s (EERE’s) strategic goals is to stimulate the growth of a thriving domestic clean energy manufacturing industry. This report seeks to identify products in the European and U.S. markets that can enable a more integrated and standardized approach to conducting zero energy retrofits, leveraging off-site construction and manufacturing. Greater integration of energy conservation measures into prefabricated building components will further enable efficiency adoption, while reducing project complexity, risks, and costs.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Optimization of the Shielding of a Canister Loading Machine with the deterministic Code Attila{sup R} - Paper 61

In general shielding components are designed with very conservative assumptions and boundary conditions to cover all possibly occurring situations. This often results in an overestimated shielding design in a lot of different fields of application; the shielding of components will be heavier and more expensive than needed. In most cases an initial shielding calculation in the design process shows an unbalanced shielding effect of the shielded radiation source. Sometimes the dose rate limits are slightly exceeded in several areas. From this arises a need for an optimization of the shielding structure. The goal is to decrease the radiation level in the accessible areas to keep the dose rate limits and to reduce the amount of the used shielding material if possible. Shielding material is moved from areas with higher shielding factors to which with lower ones. The optimization process is shown in an example of a loading machine for vitrified waste in canisters. The design review with an optimization of the shielding geometry was done with the deterministic code Attila{sup R} of the company Transpire, Inc. Attila{sup R} is a powerful tool to calculate and optimize the shielding effect of handling facilities for radioactive materials. It is easy to handle with its CAD integration module and an easy setup of the calculation cases. Areas with a low shielding effect which results in an exceeding of the dose rate limits can be found quickly with the illustration due to an Iso-Dose-Rate-Surface in the 3D Model. In these areas the shielding effect has to be improved. Otherwise there is material, which has no significant influence on the shielding effect and makes the handling facilities heavier and more expensive as needed. The optimization of the shielding design of the canister loading machine in the current case results in lower dose rates outside the facility to keep the dose rate limits. The demand of shielding material could be reduced and resulted in a cost reduction on the facility itself and furthermore in the caring facilities to transport this facility (cranes, etc.). (authors)

42 ENGINEERING↗
DOE OSTI2014

simuwatt - A Tablet Based Electronic Auditing Tool

'simuwatt Energy Auditor' (TM) is a new tablet-based electronic auditing tool that is designed to dramatically reduce the time and cost to perform investment-grade audits and improve quality and consistency. The tool uses the U.S. Department of Energy's OpenStudio modeling platform and integrated Building Component Library to automate modeling and analysis. simuwatt's software-guided workflow helps users gather required data, and provides the data in a standard electronic format that is automatically converted to a baseline OpenStudio model for energy analysis. The baseline energy model is calibrated against actual monthly energy use to ASHRAE Standard 14 guidelines. Energy conservation measures from the Building Component Library are then evaluated using OpenStudio's parametric analysis capability. Automated reporting creates audit documents that describe recommended packages of energy conservation measures. The development of this tool was partially funded by the U.S. Department of Defense's Environmental Security Technology Certification Program. As part of this program, the tool is being tested at 13 buildings on 5 Department of Defense sites across the United States. Results of the first simuwatt audit tool demonstration are presented in this paper.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Macro-encapsulation as Manufactured Components for Disposal at the Nevada National Security Site (NNSS) - 16213

Macro-encapsulation as Manufactured is a relatively new terminology that supports the disposal of classified legacy weapon components at the Area 5 Disposal Cell at the Nevada National Security Site (NNSS). These components are composed of hundreds and sometimes thousands of parts. Examples of this type of item include firing sets, trainers, radar assemblies, neutron generators and other similar components. Sometimes there are hazardous Resource Conservation and Recovery Act-regulated (RCRA) metals involved in the parts that make up the components. The typical regulated metals in the components can be lead and silver from circuit boards and wiring, cadmium or chromium from plating operations of the parts. To perform the Toxicity Characteristic Leaching Procedure (TCLP) components have to be completely disassembled and sanitized prior to being sent to laboratories for analysis. The results vary but the majority of times there are regulated metals present in these samples. The levels are relatively low and since analysis has been performed then a disposal process needs to be followed. A process needed to be developed and approved by governing boards to allow disposal of these items as long as this material meets the Waste Acceptance Criteria (WAC) (No liquids, compressed gases, explosives, SNM, etc.) before being sent to the Nevada desert for disposal. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Longevity of geo-synthetic cover components - 15450

Geo-synthetics form many of the key components in modern landfill cell and final cover designs. Models for the long-term performance assessment of systems incorporating these components have traditionally relied on a small number of standard assumptions originally developed to address the needs of the Resource Conservation and Recovery Act (RCRA) Subtitle D solid waste industry. These past estimates demonstrated that, even under a series of highly conservative factors, the longevity of these components far exceeds the requirements for typical solid waste facilities. Traditionally, the interpretation of the geo-synthetic degradation research has been deterministic as opposed to probabilistic, often due to the relative scarcity of degradation data for particular formulations and environmental conditions. Long-term studies of the mechanical and chemical properties of geo-synthetics subjected to accelerated aging processes have been conducted in an attempt to better quantify their longevity to address applications where performance may be required for 1,000 years or more. Of the many cover system geo-synthetic components, geo-membranes appear to have the most significant impact on the long-term performance of cover systems. Based on available long-term aging studies, a series of property degradation curves and their corresponding model parameters are available for geo-membranes. A strong area of need in the performance assessment of shallow disposal facilities is how to connect these research findings with inputs to probabilistic models. Significantly, factors affecting geo-membrane performance, such as geo-membrane thickness, anti-oxidant package, molecular weight, oxygen exposure, and drainage, can be adjusted and re-engineered using a proposed approach to meet specific performance targets. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗