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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 1,189 records · Page 66
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Compressed Natural Gas Component Leak Frequency Estimation

The frequency of unintended releases in a compressed natural gas system is an important aspect of the system quantitative risk assessment. The frequencies for possible release scenarios, along with engineering models, are utilized to quantify the risks for compressed natural gas facilities. This report documents component leakage frequencies representative of compressed natural gas components that were estimated as a function of the normalized leak size. A Bayesian statistical method was used which results in leak frequency distributions for each component which represent variation and uncertainty in the leak frequency. The analysis shows that there is high uncertainty in the estimated leak frequencies due to sparsity in compressed natural gas data. These leak frequencies may still be useful in compressed natural gas system risk assessments, as long as this high uncertainty is acknowledged and considered appropriately.

03 NATURAL GAS↗
DOE OSTI2023

Simulating target tests at AP0 facility for Mu2e

The predicted production of muons and energy deposition for the production target of the Mu2e experiment are dependent on the documentation of cross-sections values, the properties of the target’s material, etc. Hence, making real tests on similar targets before its use on Mu2e will be a good indicator of the accuracy of the simulations done for the experiment. The main goal of the project is to simulate a target test at the AP0 Target Facility, previously used to create the muon beam for the Muon g-2 experiment. Results from these simulations will be used as input to engineering models of the target to produce predicted stress and surface temperature distributions, parameters that will later be measured in future beam runs to validate underlying cross section models.

Delgado, Amii Matamoros↗
DOE OSTI2023

Fission Product Mass Yields in Uranium-233 and Plutonium-239 from Fast-Neutron-Induced Fission

Precise knowledge of nuclear fission is a critical component for nuclear energy and stockpile stewardship research. Despite having been discovered over 80 years ago, fission is not fully described by a predictive theory, so thorough and accurate nuclear data libraries are necessary. These libraries provide information about the fission process in studied isotopes that is used in scientific and engineering models.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Coal-based Bricks & Blocks (CBBs): Process Development to Prototype Fabrication Coupled with Techno-Economic Analysis and Market Survey

Coal-based bricks and blocks (CBBs) were formulated using anthracite and thermoplastic binder. Lab scale test composites were formed by hot-press molding and commercial extrusion for test articles and for a full-scale prototype. Formulations and test matrices followed a systematic experimental design to examine the effects of and interactions among three primary independent variables: a) thermoplastic type, b) weight fractions of binder relative to the total anthracite weight, and c) relative proportions of large versus small (milled) anthracite size fractions. Technical performance metrics include compressive strength, modulus, porosity/permeability and density. These DoE studies establish composition-property relations and identify the best combination for any desired property of interest – in particular, strength. Based on CBB composition and fabrication process, validated against technical performance metrics, a techno-economic analysis was constructed which incorporated a process flow model, engineering design (with scaling), and calculated capital plus operating costs. Based on measured property metrics and estimated process economics and a projected price by TEA (techno-economic analysis), building and construction target markets were identified by a market survey assessment. With known cost, price, performance metrics and competitive advantages for CBBs matched with commercial applications/uses, a technical gap analysis was performed to identify further development required for scale-up and commercialization.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2025

Optimizing Hydronic Heating for Comfort and Performance in Multifamily Housing

Inefficient control settings in multifamily boilers often lead to substantial energy and cost penalties. To address this, a Fault Detection and Diagnostic (FDD) tool was developed to automate data analysis and identify operational faults such as suboptimal outdoor temperature sensor placement, misconfigured outdoor air reset (OAR) curves, excess boiler cycling, and domestic hot water (DHW) setpoint errors. By comparing pre- and post-implementation periods and applying engineering models, the tool quantifies energy savings and reduces manual analysis time by over 90%. Testing on over 100 monitored sites and a targeted subset of 12 buildings showed an average 11% energy savings from remote optimization; further validation across 19 OAR curve changes confirmed the tool’s accuracy, predicting actual savings within ±5% for most cases. Simple payback can be under three years for many multifamily buildings, though rising hardware, labor, and fuel costs create uncertainties, and decarbonization goals increasingly shift focus to electrification. The FDD tool remains invaluable for optimizing existing boilers, enhancing future electrification measures, and adapting to new technologies by refining building load estimates. In doing so, it supports both near-term efficiency and long-term transitions to low-carbon alternatives, ensuring buildings achieve substantial cost and energy benefits throughout their system lifecycles.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Predicting long-term stress relaxation on Alloy 709 using the crystal plasticity finite element method

This report summarizes the results of physics-based, crystal plasticity simulations for the long-term stress relaxation behavior of Alloy 709. The purpose of the study was to provide insight into five key questions related to long-term behavior in high temperatures materials which are difficult or impossible to answer experimentally: (1) is there a threshold stress for long-term relaxation? (2) is there strain threshold for relaxation damage, below which significant damage does not accumulate? (3) does damage continue to accumulate as the material relaxes or will damage accumulation plateau under some loading conditions? (4) does stress relaxation loading inevitably lead to failure? and (5) which, if any, engineering models for relaxation damage accumulation reasonably match the simulation results? The report summarizes the numerical simulations used to address these five questions and provides at least partial answers to each question.

36 MATERIALS SCIENCE↗
DOE OSTI2019

FAST.Farm Response to Varying Wind Inflow and Discretization

FAST.Farm is a newly developed multiphysics, midfidelity engineering tool that can be used to predict turbine power and structural loads of wind turbines in a wind farm. Previous studies have shown the similarities and differences between FAST.Farm and large-eddy simulations (LES) using the same LES-precursor-generated ambient wind inflow. The ability to generate ambient wind inflow using a synthetic turbulence engineering model (e.g., TurbSim or the Mann model) has recently been integrated into FAST.Farm to potentially enable more computationally efficient usage of the tool. This work aims to: 1) compare FAST.Farm simulations using LES-generated inflow to those using synthetically generated inflow from TurbSim, and 2) establish guidelines by which TurbSim-generated inflow should be generated for wind farm analysis. It was found that properly setting spatial coherence parameters for the transverse wind velocity components is necessary to accurately predict wake meandering. It is shown that TurbSim-generated inflow can be used in FAST.Farm to accurately predict thrust, power, speed, and torque for waked and unwaked turbines; wake meandering behavior across different atmospheric conditions; and averaged wake-deficit advection and evolution effects.

17 WIND ENERGY↗
DOE OSTI2017

What Can We Learn about GRB from the Variability Timescale Related Correlations?

Recently, two empirical correlations related to the minimum variability timescale (MTS) of the light curves are discovered in gamma-ray bursts (GRBs). One is the anti-correlation between MTS and Lorentz factor Γ, and the other is the anti-correlation between the MTS and gamma-ray luminosity L {sub γ}. Both of the two correlations might be used to explore the activity of the central engine of GRBs. In this paper, we try to understand these empirical correlations by combining two popular black hole central engine models (namely, the Blandford and Znajek mechanism (BZ) and the neutrino-dominated accretion flow (NDAF)). By taking the MTS as the timescale of viscous instability of the NDAF, we find that these correlations favor the scenario in which the jet is driven by the BZ mechanism.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

A simulation study demonstrating the importance of large-scale trailing vortices in wake steering

In this article, we investigate the role of flow structures generated in wind farm control through yaw misalignment. A pair of counter-rotating vortices are shown to be important in deforming the shape of the wake and in explaining the asymmetry of wake steering in oppositely signed yaw angles. We motivate the development of new physics for control-oriented engineering models of wind farm control, which include the effects of these large-scale flow structures. Such a new model would improve the predictability of control-oriented models. Results presented in this paper indicate that wind farm control strategies, based on new control-oriented models with new physics, that target total flow control over wake redirection may be different, and perhaps more effective, than current approaches. We propose that wind farm control and wake steering should be thought of as the generation of large-scale flow structures, which will aid in the improved performance of wind farms.

17 WIND ENERGY↗
DOE OSTI2023

Increased power gains from wake steering control using preview wind direction information

Abstract. Yaw controllers typically rely on measurements taken at the wind turbine, resulting in a slow reaction to wind direction changes and subsequent power losses due to misalignments. Delayed yaw action is especially problematic in wake steering operation because it can result in power losses when the yaw misalignment angle deviates from the intended one due to a changing wind direction. This study explores the use of preview wind direction information for wake steering control in a two-turbine setup with a wind speed in the partial load range. For these conditions and a simple yaw controller, results from an engineering model identify an optimum preview time of 90 s. These results are validated by forcing wind direction changes in a large-eddy simulation model. For a set of six simulations with large wind direction changes, the average power gain from wake steering increases from only 0.44 % to 1.32 %. For a second set of six simulations with smaller wind direction changes, the average power gain from wake steering increases from 1.24 % to 1.85 %. Low-frequency fluctuations are shown to have a larger impact on the performance of wake steering and the effectiveness of preview control, in particular, than high-frequency fluctuations. From these results, it is concluded that the benefit of preview wind direction control for wake steering is substantial, making it a topic worth pursuing in future work.

17 WIND ENERGY↗
NASA NTRS1968

Environmental requirements

Engineering models of Venus atmosphere, and application of thermal modeling to spacecraft sterilization

Source record↗
NASA NTRS1971

Urine sampling and collection system

This specification defines the performance and design requirements for the urine sampling and collection system engineering model and establishes requirements for its design, development, and test. The model shall provide conceptual verification of a system applicable to manned space flight which will automatically provide for collection, volume sensing, and sampling of urine.

Fogal, G. L.↗
NASA NTRS1972

Fuel cell technology program

A program to advance the technology for a cost-effective hydrogen/oxygen fuel cell system for future manned spacecraft is discussed. The evaluation of base line design concepts and the development of product improvements in the areas of life, power, specific weight and volume, versatility of operation, field maintenance and thermal control were conducted from the material and component level through the fabrication and test of an engineering model of the fuel cell system. The program was to be accomplished in a 13 month period.

Source record↗