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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Calculation of Friction Factors and Nusselt Numbers for Twisted Elliptical Tube Heat Exchangers Using Nek5000

Twisted elliptical tube geometries for heat exchanger design are expected to offer significant enhancement in heat transfer with a marginal increase in frictional losses. The presented work focuses on computational fluid dynamics (CFD) simulations of heated molten salt flows through twisted elliptical tube geometries at low modified Froude numbers. In this work, the objectives are to evaluate the available correlations at low Froude numbers and to determine the impact of using a small gap to resolve contact points. The spectral element CFD code Nek5000 was used for all simulations, which were performed in periodic domains of triangular and square unit cells surrounding a single tube through a complete twist using an explicit filtering large eddy simulation (LES) method. The simulation methodology was validated by comparing to the experimental data of Tan et al. Excellent agreement was observed for this comparison. The Dzyubenko correlation for transitional flow was evaluated for a range of Froude numbers. This correlation demonstrated good agreement with LES results at high modified Froude number. As Froude number was decreased toward the bounds of the correlation, the agreement worsened. Cases were then simulated at low Froude number, testing the effects of tube spacing. It was determined that the laminar case for the square unit cell is the most affected by increasing gap size, which should be minimized to mitigate the effect. In the triangular unit cell, the laminar flow regime is also more significantly impacted by increasing gap size compared to the turbulent flow regime which was only marginally impacted.

42 ENGINEERING↗
DOE OSTI2018

Absorption/Desorption based high efficiency Supercritical Carbon Dioxide Power Cycles - Final Scientific/Technical Report

The team of Southwest Research Institute® (SwRI®) and Thar Energy LLC (Thar) are advancing the state of the art in fossil-fired closed Brayton supercritical carbon dioxide (sCO 2 ) power cycles. This current effort is focused on evaluating the integration of a fossil-based thermal system with closed Brayton sCO 2 power blocks to understand the impact of thermal integration on plant performance and identification of current technology gaps. This effort is extending the current understanding of how fossil-based thermal systems may best be integrated with recuperated closed Brayton cycles based on the overall impact on the integrated plant efficiency, cost, and operating characteristics. System Engineering Design and Thermodynamic Analysis is being utilized to (1) identify technical challenges impacting the integration of fossil-based thermal sources with highly recuperated closed Brayton sCO 2 power cycles, (2) evaluate the impact of boiler design and sCO 2 cycle configuration on integrated plant performance, cost, and operability, and (3) evaluate technology readiness of the integrated system and identify specific technologies requiring development of advanced fossil-based sCO 2 cycles. Engineering evaluation is being applied to coal- and natural gas-fired thermal systems for sCO 2 power cycles to evaluate current boiler technologies and challenges associated with adapting those to a sCO 2 based configuration. This includes technical evaluation of the sCO 2 heat exchanger design and anticipated performance impacts on the thermal system. In addition to the general evaluation of indirect fossil fires closed Brayton sCO 2 cycles, this effort is also evaluating a novel indirect sCO 2 power cycle that utilizes an absorption/desorption circuit to minimize compression work by 40% to 65%. This translates to a thermodynamic cycle efficiency improvement of 3.2 points for a simple recuperated cycle using a binary CO 2 + Acetone working fluid.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2024

Improved PARE (Pressurized Airborne Release Equipment) for Damage Ratio, Airborne Release Fraction and Respirable Fraction Testing (Version 4)

This paper describes an improved version of the PARE (Pressurized Airborne Release Equipment) system (Sutter 1983a and Sutter 1983b and Ballinger et al 1987) for powder venting testing. This effort seeks to improve the accuracy of risk estimation for the venting of pressurized powders and the venting of gases through pressurized powders. This includes experimental measurement for estimating DR (damage ratio), ARF (airborne release fraction) and RF (respirable fraction) quantities. The present study was performed to address previously indicated problematic factors (i.e. noted gaps) (US DOE 1994).

42 ENGINEERING↗
DOE OSTI2024

PSU ESI Review

A guide to developing an Energy Service Interface (ESI) was created as part of the Grid Modernization Laboratory Consortium 2.5.2 ESI project. The approach applies device-agnostic and service-oriented ESI principles and leverages documents such as the Interoperability Maturity Model and Common Grid Service Definitions to provide a methodology to review, develop, and update standards and profiles to engage distributed energy resources (DER) to provide grid services. This document evaluates the ESI developed by Portland State University’s Power Engineering Group under the Electric Grid of Things project funded by the U.S. Department of Energy. The evaluation explores the compliance of this specific implementation with the GMLC ESI principles to provide an example of an ESI profile and gap analysis.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2022

The Effect of Supernova Convection On Neutron Star and Black Hole Masses

Abstract Our understanding of the convective-engine paradigm driving core-collapse supernovae has been used for two decades to predict the remnant mass distribution from stellar collapse. These predictions improve as our understanding of this engine increases. In this paper, we review our current understanding of convection (in particular, the growth rate of convection) in stellar collapse and study its effect on the remnant mass distribution. We show how the depth of the mass gap between neutron stars and black holes can help probe this convective growth. We include a study of the effects of stochasticity in both the stellar structure and the convective seeds caused by stellar burning. We study the role of rotation and its effect on the pair-instability mass gap. Under the paradigm limiting stellar rotation to those stars in tight binaries, we determine the effect of rotation on the remnant mass distribution.

Fryer, Chris L. (ORCID:0000000326240056)↗
DOE OSTI2026

Mapping the Gap: Analysis of Nuclear Cybersecurity Education in U.S. Universities

The U.S. nuclear sector is undergoing rapid transformation, driven by the expansion of advanced reactors, digital modernization of legacy systems, and increasing interest in nuclear energy to meet AI-fueled energy demands. However, the cybersecurity talent pipeline is not keeping pace with this growth. This paper investigates the significant gap in nuclear cybersecurity education and proposes scalable strategies for colleges to address this critical need by promoting it as a viable and essential career path. Through a multi-institutional landscape analysis of 16 cybersecurity and 12 nuclear engineering programs, we found that nuclear cybersecurity is largely absent from university curricula. Most students are unaware of the field’s existence, and few institutions offer hands-on training or interdisciplinary exposure. This lack of awareness leads to a shortage of specialized talent, forcing nuclear facilities to retrain generalist hires or rely on costly external consultants. We present a framework for early pipeline cultivation grounded in Social Cognitive Career Theory and workforce development principles. Proposed solutions include student-led clubs, guest lectures, modular classroom kits, and summer boot camps. By increasing visibility and access to nuclear cyber content, we aim to break the self-reinforcing cycle of low awareness and limited specialization. This work underscores the critical role of education and advocacy in cultivating early interest and guiding students toward this emerging field. We call on academic institutions, national laboratories, and industry stakeholders to collaborate in establishing nuclear cybersecurity as a distinct and accessible career path within the broader cybersecurity and nuclear engineering ecosystems.

99 - GENERAL AND MISCELLANEOUS↗
NASA NTRS1974

Investigation of abort procedures for space shuttle-type vehicles

An investigation has been made of abort procedures for space shuttle-type vehicles using a point mass trajectory optimization program known as POST. This study determined the minimum time gap between immediate and once-around safe return to the launch site from a baseline due-East launch trajectory for an alternate space shuttle concept which experiences an instantaneous loss of 25 percent of the total main engine thrust.

Powell, R. W.↗
NASA NTRS1989

The Next Generation Space Telescope

In Space Science in the Twenty-First Century, the Space Science Board of the National Research Council identified high-resolution-interferometry and high-throughput instruments as the imperative new initiatives for NASA in astronomy for the two decades spanning 1995 to 2015. In the optical range, the study recommended an 8 to 16-meter space telescope, destined to be the successor of the Hubble Space Telescope (HST), and to complement the ground-based 8 to 10-meter-class telescopes presently under construction. It might seem too early to start planning for a successor to HST. In fact, we are late. The lead time for such major missions is typically 25 years, and HST has been in the making even longer with its inception dating back to the early 1960s. The maturity of space technology and a more substantial technological base may lead to a shorter time scale for the development of the Next Generation Space Telescope (NGST). Optimistically, one could therefore anticipate that NGST be flown as early as 2010. On the other hand, the planned lifetime of HST is 15 years. So, even under the best circumstances, there will be a five year gap between the end of HST and the start of NGST. The purpose of this first workshop dedicated to NGST was to survey its scientific potential and technical challenges. The three-day meeting brought together 130 astronomers and engineers from government, industry and universities. Participants explored the technologies needed for building and operating the observatory, reviewed the current status and future prospects for astronomical instrumentation, and discussed the launch and space support capabilities likely to be available in the next decade. To focus discussion, the invited speakers were asked to base their presentations on two nominal concepts, a 10-meter telescope in space in high earth orbit, and a 16-meter telescope on the moon. The workshop closed with a panel discussion focused mainly on the scientific case, siting, and the programmatic approach needed to bring NGST into being. The essential points of this panel discussion have been incorporated into a series of recommendations that represent the conclusions of the workshop. Speakers were asked to provide manuscripts of their presentation. Those received were reproduced here with only minor editorial changes. The few missing papers have been replaced by the presentation viewgraphs. The discussion that follows each speaker's paper was derived from the question and answer sheets, or if unavailable, from the tapes of the meeting. In the latter case, the editors have made every effort to faithfully represent the discussion.

Bely, Pierre-Yves↗
NASA NTRS2004

Requirements to Design to Code: Towards a Fully Formal Approach to Automatic Code Generation

A general-purpose method to mechanically transform system requirements into a provably equivalent model has yet to appear. Such a method represents a necessary step toward high-dependability system engineering for numerous possible application domains, including sensor networks and autonomous systems. Currently available tools and methods that start with a formal model of a system and mechanically produce a provably equivalent implementation are valuable but not sufficient. The gap that current tools and methods leave unfilled is that their formal models cannot be proven to be equivalent to the system requirements as originated by the customer. For the classes of systems whose behavior can be described as a finite (but significant) set of scenarios, we offer a method for mechanically transforming requirements (expressed in restricted natural language, or in other appropriate graphical notations) into a provably equivalent formal model that can be used as the basis for code generation and other transformations.

Hinchey, Michael G.↗
NASA NTRS2005

Towards an Automated Development Methodology for Dependable Systems with Application to Sensor Networks

A general-purpose method to mechanically transform system requirements into a probably equivalent model has yet to appeal: Such a method represents a necessary step toward high-dependability system engineering for numerous possible application domains, including sensor networks and autonomous systems. Currently available tools and methods that start with a formal model of a system and mechanically produce a probably equivalent implementation are valuable but not su8cient. The "gap" unfilled by such tools and methods is that their. formal models cannot be proven to be equivalent to the system requirements as originated by the customel: For the classes of systems whose behavior can be described as a finite (but significant) set of scenarios, we offer a method for mechanically transforming requirements (expressed in restricted natural language, or in other appropriate graphical notations) into a probably equivalent formal model that can be used as the basis for code generation and other transformations.

Hinchey, Michael G.↗
DOE OSTI2019

Double-sided LCLC-compensated topology for capacitive power transfer

A double-sided LCLC-compensated network is proposed for a capacitive power transfer (CPT) system. In one design, four metal plates are used to form two power transmitting and receiving capacitors and the LCLC network is used to compensate the capacitors. In the second design, two extra metal plates are used to couple with the previous four plates at the transmitting and receiving side, respectively, which forms the capacitor-integrated structure. The circuit parameter values are tuned to achieve zero voltage switching (ZVS) of the input side switches. There is also a CLLC topology proposed, which is a similar variation of LCLC circuit. A 3.3 kW input power capacitive power transfer prototype is designed and built. The experiment results show that the proposed CPT system can transfer 3.1 kW output power through an air gap distance of 70 mm with a dc-to-dc efficiency of 92.1%.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2022

Development of a Data Platform for High-Temperature Gas-cooled Reactor (HTGR) Nuclear Energy University Program (NEUP) Thermal-Fluid Experiments

Since the U.S. Department of Energy (DOE)’s Office of Nuclear Energy (NE) initiated the Nuclear Energy University Program (NEUP) in 2009, a total of 30 NEUP projects focused on High-Temperature Gas-cooled Reactor (HTGR) thermal-fluid experiments were funded up to fiscal year (FY) 2021. This represents a total DOE investment of approximately $23M over the 12-year period, covering thermal fluid phenomena important to both pebble bed and prismatic HTGR designs. The NEUP projects have produced a large amount of high-quality experimental and computational data that were published in final project reports, journal articles, dissertations, and conference proceedings, but in most cases the actual data sets and supporting information such as facility and instrumentation descriptions were not publicly disseminated to the HTGR community. To the authors’ best knowledge, a data platform that organizes and summarizes these NEUP-funded projects for HTGR research does not currently exist. To improve access to this HTGR validation data and optimize the return on the significant investment made by DOE, the Advanced Reactor Technologies (ART) Gas-Cooled Reactor (GCR) program started a survey of completed and ongoing HTGR NEUP projects with the aim of developing a public-access data platform that can be used to retrieve computational fluid dynamics (CFD) and system code validation data and guide future NEUP investments. This paper summarizes the status of the current ART-GCR database, provides an overview of the NEUP-funded HTGR-related research projects from FY2009 to FY2021 and identify validation knowledge gaps still existing in HTGR thermal-fluid research.

42 ENGINEERING↗
DOE OSTI2020

Technology Development for Dry Storage of Aluminum-Clad Spent Nuclear Fuel - 20490

A candidate disposition pathway for the > 13 MTHM of aluminum-clad spent nuclear fuel (ASNF), owned and managed by the U.S. Department of Energy, is the drying and placement of the SNF into sealed-canister dry storage, with the ASNF-in- canisters 'road-ready' for transportation to and final direct disposal in a repository waste package. Technical information gaps in fuel drying, and fuel dry storage behavior, have previously challenged the declaration of technology readiness for drying and placement of this fuel into the DOE Standard Canister design for > 50 years of safe dry storage. The principal technical information gaps included: i) characterization and thermal dehydration behavior of aluminum (oxy)hydroxide films attendant on the cladding due to film formation during reactor operation and during post-discharge up to long-term wet storage histories; and ii) G-value data to enable estimation of the radiolytic gas generation from the cladding with its (oxy)hydroxide films. Thus, the oxide films on the ASNF challenged the safety of a sealed storage canister with thermal and radiolytic decomposition of the waters on the films that can lead to corrosion, pressurization, and flammability issues. These gaps in the technical information base have largely been closed. This paper discusses the investigations at the Idaho National Laboratory (INL) and the Savannah River National laboratory (SRNL), and outlines the pending technology development work for input to an engineering design to enable a road-ready dry storage system for ASNF. The ASNF inventory considered for road-ready dry storage is stored at the Savannah River Site (SRS) and at the Idaho Nuclear Technology and Engineering Center (INTEC) at the INL. The ASNF inventory in the SRS L Basin is from foreign and domestic research reactors (FRR and DRR), and is diverse in terms of design, irradiation, and post-reactor-discharge storage conditions; these factors yield a range of characteristics of cladding oxide films on ASNF. Mixed aluminum (oxy)hydroxide (boehmite and bayerite/gibbsite) films, non-uniform in thicknesses up to a maximum local thickness bounded by 25 μm, were observed on ASNF materials removed from wet storage in the L Basin and in non-sealed dry storage at the SRS following reactor service and a long-term (up to 40+ years) interim storage history. The ASNF inventory at INTEC, in both wet and vented dry storage, is predominantly from the Advanced Test Reactor (ATR), but it also includes DRR and FRR fuel. To address a profound behavior of these films, radiolysis testing of aluminum specimens with mixed type boehmite/bayerite oxide films was performed to develop basic data on G-values for production of radiolytic hydrogen under dry storage conditions with nominal relative humidity, temperature, and cover gas. Modeling and simulation of canister internal environments with postulated inventories of oxide films provides estimation of the evolution of the conditions of the canister loaded with ASNF. Simultaneous Thermal Analysis (TGA/DSC) of hydrated oxide powders, and laboratory-scale aluminum specimens with a bayerite film (∼10 μm) using TGA methods, inform drying time/temperature conditions to be used for the ASNF. A demonstration project is recommended for Verification and Validation of the drying and storage of the ASNF. Remaining major tasks leading up to the hot demonstration include scale-up radiolysis testing and scale-up drying testing. Engineering design with the information from the technology program will establish the safety basis and enable long-term (> 50 years) dry storage compatibility with ASNF in the DOE Standard Canister pending its transportation to and disposal in a repository. This full capability would show the ASNF-in-canister storage system to be road-ready. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Metadata Schemas and Ontologies for Building Energy Applications: A Critical Review and Use Case Analysis

With the increasing digitalization of processes throughout the lifecycle of buildings, data exchanged between stakeholders and between building systems has grown significantly. However, a lack of semantic interoperability between data in different systems is still prevalent, hindering the development of applications that can be reused across buildings and limiting the scalability of innovative solutions. Semantics refers to the description of the meaning of the data in a way that can be consistently understood by applications. Recently, several competing initiatives have been developing metadata schemas and ontologies to express this semantic information for different applications in the building domain. This paper systematically reviews these schemas and conducts an analysis of five of them to evaluate their applicability to three high-value use cases for building operations: energy audits, automated fault detection and diagnostics and optimal control. The survey finds 40 schemas published in the last 10 years but but their actual use in industry is difficult to estimate. Among the five selected ontologies, several gaps are highlighted in relation to the three use cases. Recommendations for the future include better harmonization of these initiatives, more centralized repositories and search engines for these schemas as well as better industry engagement to facilitate their adoption.

Smart Building, Sematic, Metadata, Ontology, Data ↗
DOE OSTI2017

Defect Engineering in Multinary Earth‐Abundant Chalcogenide Photovoltaic Materials

Application of zinc‐blende‐related chalcogenide absorbers such as CdTe and Cu(In,Ga)Se 2 (CIGSe) has enabled remarkable advancement in laboratory‐ and commercial‐scale thin‐film photovoltaic performance; however concerns remain regarding the toxicity (CdTe) and scarcity (CIGSe/CdTe) of the constituent elements. Recently, kesterite‐based Cu 2 ZnSn(S,Se) 4 (CZTSSe) materials have emerged as attractive non‐toxic and earth‐abundant absorber candidates. Despite the similarities between CZTSSe and CIGSe/CdTe, the record power conversion efficiency of CZTSSe solar cells (12.6%) remains significantly lower than that of CIGSe (22.6%) and CdTe (22.1%) devices, with the performance gap primarily being attributed to cationic disordering and associated band tailing. To capture the promise of kesterite‐like materials as prospective “drop‐in” earth‐abundant replacements for closely‐related CIGSe, current research has focused on several key directions to control disorder, including: (i) examination of the interaction between processing conditions and atomic site disorder, (ii) isoelectronic cation substitution to introduce ionic size mismatch, and (iii) structural diversification beyond the zinc‐blende‐type coordination environment. In this review, recent efforts targeting accurate identification and engineering of anti‐site disorder in kesterite‐based CZTSSe are considered. Lessons learned from CZTSSe are applied to other complex chalcogenide semiconductors, in an effort to develop promising pathways to avoid anti‐site disordering and associated band tailing in future high‐performance earth‐abundant photovoltaic technologies.

Shin, Donghyeop↗
DOE OSTI2017

A Further Study of the t{sub Burst} of GRBs: Rest-frame Properties, External Plateau Contributions, and Multiple Parameter Analysis

Zhang et al. propose to redefine the true γ-ray burst (GRB) central engine activity duration, t{sub burst}, by considering the contributions from the prompt γ-ray emission, X-ray flare, and internal plateau features. With a comprehensive study of a large sample of Swift GRBs, it is shown that the t{sub burst} distribution in the observer frame consists of a bimodal feature, suggesting the existence of a new population of ultra-long GRBs. In this work, we make a series of further studies on t{sub burst}: we update the Swift GRB sample up to 2016 June; we investigate the properties of t{sub burst} distribution in the rest frame; we redefine t{sub burst} by involving external plateau contributions; and we make a multiple parameter analysis to investigate whether the bursts within the ultra-long population are statistically different in the sense of other features besides the duration distribution. We find that for all situations, the distribution of t{sub burst} requires two normal distributions in logarithmic space to provide a good fit both in the observer frame and in the rest frame. Considering the observational gap effect would not completely erase the bimodal distribution feature. However, the bursts within the ultra-long population may have no statistical difference in the sense of other features besides the duration term. We thus suggest that if the ultra-long population of GRBs indeed exists, their central engine and radiation mechanisms should be similar to those of the normal population, but they have a longer central engine activity timescale.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Annealing induced microstructure engineering of antimony tri-selenide thin films

Highlights: • Deposition of Sb{sub 2}Se{sub 3} thin films using thermal vapour deposition. • Films are deposited on substrates with concurrent heating and without heating. • Effect of post deposition annealing on the two types of films are investigated. • Influence of temperature and processing conditions on optical band gap are probed. • This Sb{sub 2}Se{sub 3} films can find application in solar cells and optoelectronic devices. - Abstract: The presented work demonstrates the effect of annealing on the structural, surface morphology and optical properties of Antimony Triselenide (Sb{sub 2}Se{sub 3}) thin films deposited by thermal evaporation. Two sets of thin films of Sb{sub 2}Se{sub 3} were grown on soda lime glass (SLG) substrates by thermal evaporation with and without substrate heating. Both sets of films were then annealed at three distinct temperatures (100 °C, 200 °C and 300 °C) to study the effects of annealing on the microstructure. Analysis using XRD (X-Ray Diffraction) characterization revealed that the as-deposited films without substrate heating exhibit an amorphous nature, whereas the films grown with concurrent substrate heating are polycrystalline with orthorhombic structure. The films annealed at high temperature with concurrent substrate heating possess smooth and continuous grain morphologies. The effect of annealing was also found to have significant impact on the band gap and optical properties of the Sb{sub 2}Se{sub 3} thin films.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS2002

A Pilot Computer-Aided Design and Manufacturing Curriculum that Promotes Engineering

Elizabeth City State University (ECSU) is located in a community that is mostly rural in nature. The area is economically deprived when compared to the rest of the state. Many businesses lack the computerized equipment and skills needed to propel upward in today's technologically advanced society. This project will close the ever-widening gap between advantaged and disadvantaged workers as well as increase their participation with industry, NASA and/or other governmental agencies. Everyone recognizes computer technology as the catalyst for advances in design, prototyping, and manufacturing or the art of machining. Unprecedented quality control and cost-efficiency improvements are recognized through the use of computer technology. This technology has changed the manufacturing industry with advanced high-tech capabilities needed by NASA. With the ever-widening digital divide, we must continue to provide computer technology to those who are socio-economically disadvantaged.

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