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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Frequency- and Time-Domain Methods in Soil-Structure Interaction Analysis

Soil-structure interaction (SSI) analysis in the nuclear industry is currently performed using linear codes that function in the frequency domain. There is a consensus that these frequency-domain codes give reasonably accurate results for low-intensity ground motions that result in almost linear response. For higher intensity ground motions, which may result in nonlinear response in the soil, structure or at the vicinity of the foundation, the adequacy of frequency-domain codes is unproven. Nonlinear analysis, which is only possible in the time domain, is theoretically more appropriate in such cases. These methods are available but are rarely used due to the large computational requirements and a lack of experience with analysts and regulators. This paper presents an assessment of the linear frequency-domain code, SASSI, which is widely used in the nuclear industry, and the time-domain commercial finite-element code, LS-DYNA, for SSI analysis. The assessment involves benchmarking the SSI analysis procedure in LS-DYNA against SASSI for linearly elastic models. After affirming that SASSI and LS-DYNA result in almost identical responses for these models, they are used to perform nonlinear SSI analyses of two structures founded on soft soil. An examination of the results shows that, in spite of using identical material properties, the predictions of frequency- and time-domain codes are significantly different in the presence of nonlinear behavior such as gapping and sliding of the foundation.

42 ENGINEERING↗
DOE OSTI2022

Interim Mechanical Properties Data from FY2022 ORNL Testing of A709 with Precipitation Treatment for ASME Code Case Data Package

A collaborative research and development effort in support of the Alloy 709 Code Case qualification in the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section III, Division 5, High Temperature Reactors is being conducted at the US Department of Energy’s Oak Ridge National Laboratory, Idaho National Laboratory, and Argonne National Laboratory. A recent assessment on the Alloy 709 development and testing effort concluded that the mechanical properties of Alloy 709 with the precipitation treatment continued to outperform those of Type 316 stainless steel. The assessment also affirmed the recommendation for its Code qualification. This report provides the detailed integrated data generated to date on the two commercial heats of Alloy 709 in plate product form with precipitation treatment condition that were used as the basis for this assessment. Oak Ridge National Laboratory has continued to perform a subset of the Code Case testing for tensile properties, creep rupture, fatigue, and creep-fatigue. This report also updates the key Alloy 709 Code Case testing status and results in FY 2022 at Oak Ridge National Laboratory.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Assessing ion–electron thermal equilibration in the scrape‐off layer of tokamaks using UEDGE

The ion–electron thermal equilibration along the scrape‐off layer (SOL) has been assessed using an analytical, one‐dimensional (1D) model; a single‐flux tube model assessed with the multi‐fluid code UEDGE, and an orthogonal, two‐dimensional (2D) slab model in UEDGE for pure deuterium plasmas. These studies highlight the importance of thermal equipartition, radial transport, and loss processes in ion–electron thermal equilibration in the SOL and demonstrates the strong dependence of equipartition on local plasma parameters. For the 2D UEDGE cases, equipartition is predicted to cool the ions by up to a factor of 2 at the upstream location and to heat the electrons by up to a factor of 3, predominantly in front of the target. Diffusive radial transport into the private flux region and far SOL is predicted to reduce the upstream ion temperatures by up to 30% compared to the 1D UEDGE predictions, and volumetric power and momentum sinks (charge‐exchange, ionization, recombination, and hydrogen radiation) reduces the target ion and electron temperatures by up to one order of magnitude compared to a 1D model considering conduction and equipartition only. The losses and radial transport are, however, insufficient to achieve T i ≈ T e in the absence of thermal equipartition due to losses affecting the ions and electrons asymmetrically. UEDGE simulations on a 2D slab predicts radially varying T i / T e ratios due to radial transport, which is not considered in any 0D or 1D models of the SOL.

Holm, A.↗
DOE OSTI2014

Energy levels, radiative rates, and lifetimes for transitions in W LVIII

Energy levels and radiative rates are reported for transitions in Cl-like W LVIII. Configuration interaction (CI) has been included among 44 configurations (generating 4978 levels) over a wide energy range up to 363 Ryd, and the general-purpose relativistic atomic structure package (GRASP) adopted for the calculations. Since no other results of comparable complexity are available, calculations have also been performed with the flexible atomic code (FAC), which help in assessing the accuracy of our results. Energies are listed for the lowest 400 levels (with energies up to ∼98 Ryd), which mainly belong to the 3s{sup 2}3p{sup 5}, 3s3p{sup 6}, 3s{sup 2}3p{sup 4}3d, 3s{sup 2}3p{sup 3}3d{sup 2}, 3s3p{sup 4}3d{sup 2}, 3s{sup 2}3p{sup 2}3d{sup 3}, and 3p{sup 6}3d configurations, and radiative rates are provided for four types of transitions, i.e. E1, E2, M1, and M2. Our energy levels are assessed to be accurate to better than 0.5%, whereas radiative rates (and lifetimes) should be accurate to better than 20% for a majority of the strong transitions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Radiative rates for E1, E2, M1, and M2 transitions in Ne-like Hf LXIII, Ta LXIV and Re LXVI

Calculations for energy levels, radiative rates and lifetimes have been performed for three Ne-like ions, namely Hf LXIII, Ta LXIV and Re LXVI, for which the general-purpose relativistic atomic structure package (GRASP) has been adopted. Results are presented among the lowest 121 levels of these ions, which belong to the 2s{sup 2}2p{sup 6}, 2s{sup 2}2p{sup 5}3ℓ, 2s2p{sup 6}3ℓ, 2s{sup 2}2p{sup 5}4ℓ, 2s2p{sup 6}4ℓ, and 2s{sup 2}2p{sup 5}5ℓ configurations, but CI (configuration interaction) has been considered among a much larger number of levels. No measurements for energy levels are available but comparisons have been made with the earlier similar theoretical results. Additionally, calculations have also been performed with the flexible atomic code (FAC) in order to assess the effect of (much) larger CI on energy levels.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2025

Enhancing EnergyPlus capabilities to model dynamic building envelopes using python plugin

Nearly half of the energy consumption in the United States is related to buildings, resulting in an urgent need to develop innovative technologies to improve building energy efficiency. Dynamic building envelopes, comprising switchable insulation and thermal energy storage materials, have been proposed recently as a promising solution to reduce buildings' heating and cooling loads by thermally coupling the indoor environment with the ambient environment when beneficial while decoupling them when outdoor conditions are not favorable. Although various related technologies are still underway, the whole-building energy modeling tools, like EnergyPlus, do not have the capability to simulate the transient and dynamic nature of dynamic envelope materials and components to accurately predict their impact on building energy use. The objective of this study is to formulate a method in EnergyPlus simulation engine to model multilayer envelopes, comprising dynamic building materials with variable thermophysical properties, and discuss the changes made to the program using a Python plugin. Furthermore, the thermal performance of the dynamic envelopes using the proposed method is compared and verified with the results from a well-established commercial code, COMSOL Multiphysics. A parametric assessment is also conducted to evaluate the energy efficiency benefits of dynamic envelopes in a single-family residential building, demonstrating total annual energy savings up to 11.6 %, when a dynamic envelope operates alone, and up to 18.2 % when it is combined with a thin layer of phase change material as a thermal storage medium. Finally, a United States wide energy efficiency assessment is presented to showcase the geographical spread of the energy savings. The method designed and implemented in this study provides the researchers with the ability to implement their dynamic insulation methods in EnergyPlus and evaluate the whole building energy impact.

25 ENERGY STORAGE↗
DOE OSTI2019

Thermal Loads and Cooling Design for ITER in-Port Low Field Side Reflectometer Diagnostic System

The current design for the ITER Low Field Side Reflectometer (LFSR) diagnostic system contains six circular waveguides that function as both launch and receive antennas. The front end of LFSR system, interfacing with the plasma facing DFW and its supporting diagnostic shielding Modules (DSM), is integrated into Equatorial Port Plug 11(EPP#11). In-vessel LFSR configuration is mainly divided into two sections, i.e. Front Antenna Unit (FAU) and in-vessel Transmission Line (TL) components. During plasma normal operation, the 14 MeV neutrons from D-T fusion reactions penetrate into the port plug and LFSR components. Neutronics code ATTILA is used for assessing the volumetric heating of in-vessel components. The maximum normal heat load due to radiation and the charge exchange from plasma is 0.35 MW/m 2 , which has to be applied on those surfaces affected by a viewing factor consistent with the aperture surface position and orientation. The front antenna unit (FAU) needs the active cooling to handle the radiant and nuclear heating from the plasma. Due to the specific viewing aperture layout at the front-end of in-vessel LFSR, the cooling channel design is challenging. The thermal-hydraulic iterations are performed to achieve the desirable temperature distribution of the water cooled front antenna units. The progressive ratcheting effects of the FAU subjected to cyclic thermal loading are examined by the preliminary non-linear elastic-plastic analysis.

42 ENGINEERING↗
DOE OSTI2024

Fuel Behavior Implications of Reactor Design Choices in Pressurized Water SMRs

Small pressurized water reactors (PWRs) can feature boron free operation, natural circulation mode, reduced height assemblies and/or long refueling cycles. This paper attempts to explore core design optimization for each of these design evolutions. In consequence, five core design layouts are developed incorporating boron free operation with continuous control rods insertion, natural circulation with low burnup/low power density design, natural circulation with high burnup/low power density design, forced circulation with standard core power density design, and forced circulation with high power density design. These cores’ performance is compared to a standard 4-loop PWR. The design process aims to improve the fuel cycle cost under safety constraints through core design optimization using CASMO4E/SIMULATE3 reactor physics codes and FRAPCON4.1 fuel performance assessment tool. Core modeling assumes standard 17x17 PWR fuel assemblies loaded with low enriched uranium (LEU) up to 5wt% or LEU+ (i.e., below 10wt% enrichment) pellets with gadolinium oxide (Gd2O3) as the burnable poison. Satisfactory core and fuel performances are obtained for all the designed cores under steady state and considered overpower transients. For low power density operation, long cycle lengths are achieved reaching a 2.5- and a 5-year cycles and peak rod-average burnup is pushed to 83 MWd/kgU. Other cycle lengths are maintained at 18 months. Boron free operation exhibits the ability to achieve longer cycle lengths at the cost of higher peaking factors leading to high local power and fuel temperatures which prevents sizable power uprates and is deemed uneconomical. Fuel assembly height reduction allows coolant velocity retrofit which enables higher core power density without violating structural integrity of the fuel assembly. As a result, a core power density of 123 kW/l is reached where total cladding hoop strain becomes the limiting parameter.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2019

Design and Analysis of the US ITER Central Solenoid Module Lifting Fixture

The central solenoid (CS) consists of six large high field superconducting magnets (also known as modules) approximately 4 m in diameter and 2 m tall that weigh approximately 120 tonnes each. These large and complex modules create challenges during assembly of the CS that require the development of custom assembly tooling such as the CS lifting fixture. The CS module lifting fixture is designed to lift and stack the six CS modules in the assembly building on the ITER site. Because of its unique design, fabrication, and assembly features, no lifting attachments could be incorporated within or under the CS modules. This limitation motivated the development of a friction-based lift fixture. The design and evaluation of the CS module lifting fixture considered both worker safety and investment protection, and the assessments were performed to international codes and standards. The CS module lifting fixture consists of two principal subassemblies: spider assembly and ring weldment. These subassemblies allow the frictional force to be augmented by the mechanical advantage of shallow-angle wedges. Large radial preloads created by both screw jack assemblies and the weight of a CS module develop frictional forces capable of performing a lift with a safety factor of at least 2. The design effort resulted in the use of low friction linear bearings on angle surfaces to ensure constant pressure, integrated jacks for pretensioning the fixture prior to lifting, and load pin strain gauges for monitoring the normal force. Testing of various materials and surface treatments led to the selection of laminated aluminum and rubber pads as the friction interface on the CS lifting fixture side and a grit-blasted Nitronic 50 stainless steel band on the CS module side. A redundant lifting method using the module slings between the spider and module is also utilized after the initial friction lift. The CS lifting fixture provides a safe and reliable solution for lifting and stacking the CS module during assembly.

Morris, Eric↗
DOE OSTI2023

New cyclophilin D inhibitor rescues mitochondrial and cognitive function in Alzheimer’s disease

Abstract Mitochondrial dysfunction is an early pathological feature of Alzheimer disease and plays a crucial role in the development and progression of Alzheimer’s disease. Strategies to rescue mitochondrial function and cognition remain to be explored. Cyclophilin D (CypD), the peptidylprolyl isomerase F (PPIase), is a key component in opening the mitochondrial membrane permeability transition pore, leading to mitochondrial dysfunction and cell death. Blocking membrane permeability transition pore opening by inhibiting CypD activity is a promising therapeutic approach for Alzheimer’s disease. However, there is currently no effective CypD inhibitor for Alzheimer’s disease, with previous candidates demonstrating high toxicity, poor ability to cross the blood–brain barrier, compromised biocompatibility and low selectivity. Here, we report a new class of non-toxic and biocompatible CypD inhibitor, ebselen, using a conventional PPIase assay to screen a library of ∼2000 FDA-approved drugs with crystallographic analysis of the CypD-ebselen crystal structure (PDB code: 8EJX). More importantly, we assessed the effects of genetic and pharmacological blockade of CypD on Alzheimer’s disease mitochondrial and glycolytic bioenergetics in Alzheimer’s disease-derived mitochondrial cybrid cells, an ex vivo human sporadic Alzheimer’s disease mitochondrial model, and on synaptic function, inflammatory response and learning and memory in Alzheimer’s disease mouse models. Inhibition of CypD by ebselen protects against sporadic Alzheimer’s disease- and amyloid-β-induced mitochondrial and glycolytic perturbation, synaptic and cognitive dysfunction, together with suppressing neuroinflammation in the brain of Alzheimer’s disease mouse models, which is linked to CypD-related membrane permeability transition pore formation. Thus, CypD inhibitors have the potential to slow the progression of neurodegenerative diseases, including Alzheimer’s disease, by boosting mitochondrial bioenergetics and improving synaptic and cognitive function.

Neurosciences & Neurology↗
DOE OSTI2017

Regulatory networks underlying mycorrhizal development delineated by genome-wide expression profiling and functional analysis of the transcription factor repertoire of the plant symbiotic fungus Laccaria bicolor

Background: Ectomycorrhizal (ECM) fungi develop a mutualistic symbiotic interaction with the roots of their host plants. During this process, they undergo a series of developmental transitions from the running hyphae in the rhizosphere to the coenocytic hyphae forming finger-like structures within the root apoplastic space. These transitions, which involve profound, symbiosis-associated metabolic changes, also entail a substantial transcriptome reprogramming with coordinated waves of differentially expressed genes. To date, little is known about the key transcriptional regulators driving these changes, and the aim of the present study was to delineate and functionally characterize the transcription factor (TF) repertoire of the model ECM fungus Laccaria bicolor. Results: We curated the L. bicolor gene models coding for transcription factors and assessed their expression and regulation in Poplar and Douglas fir ectomycorrhizae. We identified 285 TFs, 191 of which share a significant similarity with known transcriptional regulators. Expression profiling of the corresponding transcripts identified TF-encoding fungal genes differentially expressed in the ECM root tips of both host plants. The L. bicolor core set of differentially expressed TFs consists of 12 and 22 genes that are, respectively, upregulated and downregulated in symbiotic tissues. These TFs resemble known fungal regulators involved in the control of fungal invasive growth, fungal cell wall integrity, carbon and nitrogen metabolism, invasive stress response and fruiting-body development. However, this core set of mycorrhiza-regulated TFs seems to be characteristic of L. bicolor and our data suggest that each mycorrhizal fungus has evolved its own set of ECM development regulators. A subset of the above TFs was functionally validated with the use of a heterologous, transcription activation assay in yeast, which also allowed the identification of previously unknown, transcriptionally active yet secreted polypeptides designated as Secreted Transcriptional Activator Proteins (STAPs). Conclusions: Transcriptional regulators required for ECM symbiosis development in L. bicolor have been uncovered and classified through genome-wide analysis. This study also identifies the STAPs as a new class of potential ECM effectors, highly expressed in mycorrhizae, which may be involved in the control of the symbiotic root transcriptome.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2012

Arrays of Bottles of Plutonium Nitrate Solution

In October and November of 1981 thirteen approaches-to-critical were performed on a remote split table machine (RSTM) in the Critical Mass Laboratory of Pacific Northwest Laboratory (PNL) in Richland, Washington using planar arrays of polyethylene bottles filled with plutonium (Pu) nitrate solution. Arrays of up to sixteen bottles were used to measure the critical number of bottles and critical array spacing with a tight fitting Plexiglas® reflector on all sides of the arrays except the top. Some experiments used Plexiglas shells fitted around each bottles to determine the effect of moderation on criticality. Each bottle contained approximately 2.4 L of Pu(NO 3 ) 4 solution with a Pu content of 105 g Pu/L and a free acid molarity H + of 5.1. The plutonium was of low 240 Pu (2.9 wt.%) content. These experiments were sponsored by Rockwell Hanford Operations because of the lack of experimental data on the criticality of arrays of bottles of Pu solution such as might be found in storage and handling at the Purex Facility at Hanford. The results of these experiments were used “to provide benchmark data to validate calculational codes used in criticality safety assessments of [the] plant configurations” (Ref. 1). Data for this evaluation were collected from the published report (Ref. 1), the approach to critical logbook, the experimenter’s logbook, and communication with the primary experimenter, B. Michael Durst. Of the 13 experiments preformed 10 were evaluated. One of the experiments was not evaluated because it had been thrown out by the experimenter, one was not evaluated because it was a repeat of another experiment and the third was not evaluated because it reported the critical number of bottles as being greater than 25. Seven of the thirteen evaluated experiments were determined to be acceptable benchmark experiments. A similar experiment using uranyl nitrate was benchmarked as U233-SOL-THERM-014.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2015

Development and Demonstration of Material Properties Database and Software for the Simulation of Flow Properties in Cementitious Materials

This report describes work performed by the Savannah River National Laboratory (SRNL) in fiscal year 2014 to develop a new Cementitious Barriers Project (CBP) software module designated as FLOExcel. FLOExcel incorporates a uniform database to capture material characterization data and a GoldSim model to define flow properties for both intact and fractured cementitious materials and estimate Darcy velocity based on specified hydraulic head gradient and matric tension. The software module includes hydraulic parameters for intact cementitious and granular materials in the database and a standalone GoldSim framework to manipulate the data. The database will be updated with new data as it comes available. The software module will later be integrated into the next release of the CBP Toolbox, Version 3.0. This report documents the development efforts for this software module. The FY14 activities described in this report focused on the following two items that form the FLOExcel package; 1) Development of a uniform database to capture CBP data for cementitious materials. In particular, the inclusion and use of hydraulic properties of the materials are emphasized; and 2) Development of algorithms and a GoldSim User Interface to calculate hydraulic flow properties of degraded and fractured cementitious materials. Hydraulic properties are required in a simulation of flow through cementitious materials such as Saltstone, waste tank fill grout, and concrete barriers. At SRNL these simulations have been performed using the PORFLOW code as part of Performance Assessments for salt waste disposal and waste tank closure.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2023

Fulcrum House – Towards a Sustainable Composite Architecture

In the last decades, the accessibility to digital fabrication technologies positioned composites as an affordable, structurally efficient and low-maintenance alternative to traditional mineral-based and high-energy materials. Of special interest are carbon nanotubes (CNT) and carbon foam (CFoam) from methane and coal pyrolysis respectively, as an environmentally friendly substitute to glass and carbon fiber. This paper presents the design of a principled single-family house, as a first case study to identify the constraints of such a material system, including technology gap, techno-economic and life cycle assessment, as well as building code requirements. In turn, the investigation proposes a suitable design-to-fabrication workflow, which potentially could bring CNT and CFoam materials to the construction of buildings.

01 COAL, LIGNITE, AND PEAT↗
NASA NTRS1982

Turbofan forced mixer-nozzle internal flowfield. Volume 2: Computational fluid dynamic predictions

A general program was conducted to develop and assess a computational method for predicting the flow properties in a turbofan forced mixed duct. The detail assessment of the resulting computer code is presented. It was found that the code provided excellent predictions of the kinematics of the mixing process throughout the entire length of the mixer nozzle. The thermal mixing process between the hot core and cold fan flows was found to be well represented in the low speed portion of the flowfield.

Werle, M. J.↗
NASA NTRS1988

Drag measurements on a body of revolution in Langley's 13-inch Magnetic Suspension and Balance System

NASA Langley's 13-inch Magnetic Suspension and Balance System (MSBS) has been used to conduct low-speed wind tunnel drag force measurements on a laminar-flow body-of-revolution free of support system interference, in order to verify the drag force measurement capabilities of the MSBS. The drag force calibrations and wind-on repeatability data obtained have verified the design capabilities for this system. A drag-prediction code has been used to assess the MSBS's usefulness in body drag estimation.

Dress, David A.↗
NASA NTRS1990

Prediction of the aerodynamic and thermal environment in turbines

A numerical study of the steady, viscous flow prediction capabilities of the three-dimensional turbine stage code ROTOR3 is presented. Computations were performed with RAI3DC, a cascade version of ROTOR3 capable of being run in a planar or annular mode. Computed results are compared with experimental data obtained for Hodson's cascade, Kopper's cascade, and United Technologies Research Center's Large Scale Rotating Rig (LSRR) first-stage stator. The code's predictive capability is assessed in terms of the accuracy of predicted airfoil loadings, performance (including secondary flows in the LSRR case), boundary layers, and heat transfer. A grid refinement study was conducted in the LSRR case in an effort to more accurately model the boundary layers on the airfoil and endwall surfaces. The effects of the inlet total pressure profile in secondary flow prediction were also assessed.

Griffin, Lisa W.↗
NASA NTRS1991

Probabilistic evaluation of fuselage-type composite structures

A methodology is developed to computationally simulate the uncertain behavior of composite structures. Uncertain behavior is the consequence of the random variation (scatter) of the primitive (independent random) variables at the constituent, ply, laminate and structural levels. This methodology is implemented in the IPACS (Integrated Probabilistic Assessment of Composite Structures) computer code. A fuselage-type composite structure is analyzed to demonstrate the code's capability. The probability distribution functions of structural responses are computed. Sensitivity of a given structural response to each primitive variable is also determined from the analyses.

Shiao, Michael C.↗