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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

Assembly and Tests of Mechanical Models of the 15-T Nb 3 Sn Dipole Demonstrator

Within the US Magnet Development Program, Fermilab is developing a 15-T Nb 3 Sn dipole demonstrator. Prior to the construction of the real magnet model, short sections and the whole structure were instrumented with strain gauges and assembled to confirm the results of structural analysis, check tooling and to gain experience with the assembly of the real magnet components. We summarize the lessons learned from these mechanical models and compares the measured data with the finite element analysis.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Fabrication and Testing of 18-mm-Period, 0.5-m-Long Nb 3 Sn Superconducting Undulator

The Advanced Photon Source at Argonne National Laboratory, in collaboration with FNAL and LBNL, is developing a Nb 3 Sn superconducting undulator with the goal of installing this device on the APS storage ring and providing APS users with the novel radiation source. A series of short, similar to ~ 8-cm-long, 18-mm-period undulator prototype magnets have been designed, fabricated, and tested. The same design was scaled to fabricate a 0.5-m-long undulator prototype. Tests of this prototype showed that the designed peak magnetic field of 1.2 T at 850 A was successfully achieved. It represents at least a 20% improvement in comparison with a NbTi SCU having the same period and magnetic gap. Test results and lessons learned from the design process are reported here.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Design, Construction, and Testing of 0.5-m, 18-mm Period Nb 3 Sn Superconducting Undulator Magnets

We report design and fabrication of a new Nb 3 Sn-based superconducting undulator (SCU) are underway at the Advanced Photon Source (APS) of Argonne National Laboratory in collaboration with Fermilab and Lawrence Berkeley National Laboratory. To develop a robust and reliable fabrication process, the magnet development consists of several steps. First, magnetic and mechanical simulations were performed to optimize the magnet design; then, the design matured further by fabricating and testing a series of very short prototypes, ~8 cm long with a period length of 18 mm. These short prototype studies were previously reported. Second, the design was scaled to an intermediate length of ~0.5 m. These two steps led to the final design of ~1.1–m-long magnets, which are currently being fabricated. The quench behavior of each 0.5-m-long undulator magnet, as well as undulator assemblies from these magnets, was studied. The first SCU magnet assembly did not meet the design specifications due to the breakdown of the insulation. With an improved design and fabrication process based on lessons learned, the second SCU assembly achieved the design undulator field of 1.2 T. The design was further optimized, and the third set of magnets was fabricated and successfully tested.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

The Challenges and Solutions of Meeting the Assembly Specifications for the 4.5 m Long MQXFA Magnets for the Hi-Luminosity LHC

The U.S. High-Luminosity LHC Accelerator Upgrade Project (HL-LHC AUP) has, in the recent years, developed assembly specifications for the 4.5 m long MQXFA magnets, which are 150 mm aperture high-field Nb 3 Sn low-β quadrupole magnets that are being built for the CERN Hi-Luminosity LHC (HL-LHC) upgrade. While the specifications were based on lessons learned from the LHC Accelerator Research Program (LARP) effort and the MQXFS and MQXFA prototype magnets, the experience gained from having both MQXFA07 and MQXFA08 magnets not meeting performance specifications during cold testing actually catalyzed a better understanding of the impact of the target assembly specifications and a subsequent refinement of the same. This paper summarizes a body of assembly data from the Pre-Series (MQXFA03-MQXFA07) and Series magnets (MQXFA08-MQXFA11) that have been built to date, and discusses the processes employed to successfully face the challenge of ensuring that the assembly specifications are met for the duration of the project.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Design and Prototyping of a Novel Toroidal Magnet System for MOLLER Experiment at Jefferson Lab

The Thomas Jefferson National Accelerator Facility (JLab) has designed a unique spectrometer system to measure the weak interaction between electrons. The experiment— Measurement of Lepton-Lepton Electroweak Reaction (MOLLER)—requires leveraging the recent 12 GeV electron beam upgrade and will run in JLab for three years. Focusing the signal for the MOLLER experiment requires five water-cooled toroidal magnets, each with unique geometry and with 7-fold symmetry. The five magnets operate in a vacuum and provide the magnetic field required to separate the incident beam electrons scattered from the target electrons (Møller scattering) and protons (elastic e-p scattering) in a liquid hydrogen target. The conceptual design was developed by the MOLLER Collaboration and was given to JLab in the form of amp turns and physical location, with additional physics requirements. This article presents prototyping of the coils and magnet support system and discusses the lessons learned during the process along with the plans for full magnet testing and installation. The JLab Magnet Group along with the MOLLER Collaboration developed the specification document that includes keep out zones to design the set of magnets. JLab contracted the design of the first toroid magnet (TM0) of the magnet system to Massachusetts Institute of Technology. The other four toroid magnets (TM1 through TM4) have been designed by JLab and are in the process of fabrication and assembly. Prototype coils of TM1-TM4 were fabricated by Everson-Tesla Incorporated, PA (USA). Finally, this article presents the unique challenges of the design, alignment, high current density, operating range, high radiation dose, and vacuum environment.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Assembly of the MOLLER Toroidal Magnets at Jefferson Lab

The MOLLER experiment at the Thomas Jefferson National Accelerator Facility (JLab) aims to precisely measure the weak interaction between electrons. This experiment leverages the 12 GeV electron beam and will run for three years. A crucial component of MOLLER is a system of five uniquely shaped water-cooled toroidal magnets. These magnets, possessing seven-fold symmetry, are designed to focus particles by separating electrons scattered off hydrogen in a liquid hydrogen target. The five magnets separate electrons scattered off electrons (Møller scattering) and protons (elastic e-p scattering) within target into approximately circular rings at the detector. Here, this paper presents the assembly process for these five toroidal magnets, detailing critical steps including epoxy application, pin insertion, soldering and brazing, coil assembly, and alignment, all performed to meet stringent magnet specifications. Additionally, it discusses challenges encountered during construction and highlights lessons learned, offering insights for future magnet development projects.

Lamont, Joseph [Thomas Jefferson National Accelera↗
DOE OSTI2026

Design and Construction of a Superconducting “Direct Wind” R&D Magnet for the EIC Interaction Region

Brookhaven National Laboratory (BNL) was chosen to host the international Electron-Ion Collider (EIC), which will collide high energy and highly polarized hadron and electron beams with a center of mass energy up to 140 GeV. The Interaction Region (IR) [1] requires several large aperture, relatively high field superconducting dipole and quadrupole magnets, some of which are very closely spaced.\r\nA value engineering effort is underway as part of the EIC Project to construct and test a Direct Wind magnet [2] (coil comprised of NbTi conductor deposited directly onto a support tube, in this instance tapered, and secured mechanically against Lorentz forces afterwards) to replace two Rutherford cable collared magnets. This magnet exceeds the combination of aperture, number of coil \r\nlayers, and magnetic field, as compared to existing accelerator and R&D Direct Wind magnets to date. Furthermore, construction has been completed using a newly commissioned winding machine, upgraded in anticipation of the upcoming EIC production coil fabrication. Design, analysis, construction issues, lessons learned and accomplishments to date shall be discussed, including the \r\nachieved corrections to multipoles made to successive coil layers based on warm magnetic measurements of preceding layers.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Remote Power Systems for Sensors on the Northern Border

The National Renewable Energy Laboratory (NREL) is working with the Department of Homeland Security (DHS) [1] to field sensors that accurately track different types of transportation across the northern border of the U.S.. To do this, the sensors require remote power so that they can be placed in the most advantageous geographical locations, often where no grid power is available. This enables the sensors to detect and track aircraft/vehicles despite natural features (e.g., mountains, ridges, valleys, trees) that often prevent standard methods (e.g., monostatic radar or visual observers) from detecting them. Without grid power, portable power systems were used to provide between 80 and 300 W continuously, even in bitter cold and when buried under feet of snow/ice. NREL provides details about the design, installation, and lessons learned from long-term deployment of a second-generation of novel power systems that used adjustable-angle photovoltaics (PV), lithium ion batteries, and fuel cells that provide power to achieve 100% up-time.

14 SOLAR ENERGY↗
DOE OSTI2024

Modifications to the JET Shattered Pellet Injector to Optimize Disruption Mitigation Experiments for Supporting ITER’s DMS Design

Shattered pellet injection (SPI) experiments on Joint European Torus (JET) are an important element in determining the physics basis for mitigating disruptions in ITER. Here, the initial design of the JET SPI system included three barrels to produce pellets with diameters of 4.5, 8.1, and 12.5 mm. The variability of the pellet speed by operating with and without a mechanical punch was limited and led to poor pellet integrity, so the mechanical punch was removed. Fragment size distribution is a function of pellet speed and the desire to change the resulting fragment size distribution was not originally a requirement. After the first set of SPI experiments on JET, different pellet sizes were considered to enable dual injection experiments with identical pellet diameters. It was also determined that speed control is necessary to improve experimental repeatability and to determine how the fragment size distribution impacts mitigation performance. Two barrels were fabricated to form pellets of 10 mm diameter and a third to form an 8.1 mm diameter pellet. New propellant valves were also fabricated and characterized to improve repeatability and overall performance. To have fine control of pellet speed, inserts to reduce the breech volume were fabricated and installed. Laboratory testing was conducted to ensure pellet release and provide a comparison of propellant gas delivered versus pellet speeds for a range of pellet types and mixtures. This article will also discuss how lessons learned from the JET SPI modifications can be applied to other SPI systems, such as the ITER SPI system, as controlling pellet release with the least amount of propellant gas is essential for optimal SPI effectiveness.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

A User-Centered Design Study in Scientific Visualization Targeting Domain Experts

The development of usable visualization solutions is essential for ensuring both their adoption and effectiveness. User-centered design principles, which involve users throughout the entire development process, have been shown to be effective in numerous information visualization endeavors. We describe how we applied these principles in scientific visualization over a two year collaboration to develop a hybrid in situ/post hoc solution tailored towards combustion researcher needs. Lastly, we examine the importance of user-centered design and lessons learned over the design process in an effort to aid others seeking to develop effective scientific visualization solutions.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

SpotSDC: Revealing the Silent Data Corruption Propagation in High-Performance Computing Systems

We report the trend of rapid technology scaling is expected to make the hardware of high-performance computing (HPC) systems more susceptible to computational errors due to random bit flips. Some bit flips may cause a program to crash or have a minimal effect on the output, but others may lead to silent data corruption (SDC), i.e., undetected yet significant output errors. Classical fault injection analysis methods employ uniform sampling of random bit flips during program execution to derive a statistical resiliency profile. However, summarizing such fault injection result with sufficient detail is difficult, and understanding the behavior of the fault-corrupted program is still a challenge. In this article, we introduce SpotSDC, a visualization system to facilitate the analysis of a program's resilience to SDC. SpotSDC provides multiple perspectives at various levels of detail of the impact on the output relative to where in the source code the flipped bit occurs, which bit is flipped, and when during the execution it happens. SpotSDC also enables users to study the code protection and provide new insights to understand the behavior of a fault-injected program. Based on lessons learned, we demonstrate how what we found can improve the fault injection campaign method.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

OpenET: Filling a Critical Data Gap in Water Management for the Western United States

The lack of consistent, accurate information on evapotranspiration (ET) and consumptive use of water by irrigated agriculture is one of the most important data gaps for water managers in the western United States (U.S.) and other arid agricultural regions globally. The ability to easily access information on ET is central to improving water budgets across the West, advancing the use of data-driven irrigation management strategies, and expanding incentive-driven conservation programs. Recent advances in remote sensing of ET have led to the development of multiple approaches for field-scale ET mapping that have been used for local and regional water resource management applications by U.S. state and federal agencies. The OpenET project is a community-driven effort that is building upon these advances to develop an operational system for generating and distributing ET data at a field scale using an ensemble of six well-established satellite-based approaches for mapping ET. Key objectives of OpenET include: Increasing access to remotely sensed ET data through a web-based data explorer and data services; supporting the use of ET data for a range of water resource management applications; and development of use cases and training resources for agricultural producers and water resource managers. Here we describe the OpenET framework, including the models used in the ensemble, the satellite, meteorological, and ancillary data inputs to the system, and the OpenET data visualization and access tools. We also summarize an extensive intercomparison and accuracy assessment conducted using ground measurements of ET from 139 flux tower sites instrumented with open path eddy covariance systems. Results calculated for 24 cropland sites from Phase I of the intercomparison and accuracy assessment demonstrate strong agreement between the satellite-driven ET models and the flux tower ET data. For the six models that have been evaluated to date (ALEXI/DisALEXI, eeMETRIC, geeSEBAL, PT-JPL, SIMS, and SSEBop) and the ensemble mean, the weighted average mean absolute error (MAE) values across all sites range from 13.6 to 21.6 mm/month at a monthly timestep, and 0.74 to 1.07 mm/day at a daily timestep. At seasonal time scales, for all but one of the models the weighted mean total ET is within ±8% of both the ensemble mean and the weighted mean total ET calculated from the flux tower data. Overall, the ensemble mean performs as well as any individual model across nearly all accuracy statistics for croplands, though some individual models may perform better for specific sites and regions. We conclude with three brief use cases to illustrate current applications and benefits of increased access to ET data, and discuss key lessons learned from the development of OpenET.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

The contribution of theory and experiments to conservation in fragmented landscapes

The clearing and fragmentation of terrestrial ecosystems is commonly acknowledged as a major cause of the decline of biodiversity. These and other predicted responses to habitat fragmentation are derived from theory, which ecologists have tested with empirical approaches ranging from observations to experimental manipulations. These empirical approaches have also identified areas of theory in need of additional development. For example, experimental studies of fragmentation have provided insights such as the key role played by the matrix surrounding fragments, the importance of edge effects, and the impacts of corridors linking fragments with one another. Much less clear, however, is the extent to which these theoretical and empirical studies – while advancing our conceptual understanding of ecological responses to landscape change – help guide management and conservation practice. We review lessons learned from landscape-scale fragmentation experiments and observational studies, present the results of a survey of fragmentation and conservation experts which probed for links and mismatches between fragmentation studies and conservation practice, and discuss how future studies can contribute to conservation practice. Our survey showed that respondents consider fragmentation theory and empirical studies and their findings important for guiding conservation and management practices. The survey also identified that there are disconnects between what is typically studied by fragmentation ecologists and factors that are central to the practice of biodiversity conservation, notably, community-based human dimensions (e.g. economic, social, health issues), policy and governance, ecosystem services, eco-evolutionary responses of species, and interaction of multiple threats to biodiversity and ecosystem processes. We discuss how these disconnects can present opportunities for experiments to continue to provide valuable recommendations for conservation practice in fragmented landscapes.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Shedding light on a Group IV (ECF11) alternative σ factor

This year marks the 50 th anniversary of the discovery of σ 70 as a protein factor that was needed for bacterial RNA polymerase to accurately transcribe a promoter in vitro. It was 25 years later that the Group IV alternative σs were described as a distinct family of proteins related to σ 70 . In the intervening time, there has been an ever-growing list of Group IV σs, numbers of genes they transcribe, insight into the diverse suite of processes they control, and appreciation for their impact on bacterial lifestyles. This work summarizes knowledge of the Rhodobacter sphaeroides σ E -ChrR pair, a member of the ECF11 subfamily of Group IV alternative σs, in protecting cells from the reactive oxygen species, singlet oxygen. It describes lessons learned from analyzing ChrR, a zinc-dependent anti-σ factor, that are generally applicable to Group IV σs and relevant to the response to single oxygen. This MicroReview also illustrates insights into stress responses in this and other bacteria that have been acquired by analyzing or modeling the activity of the σ E -ChrR across the bacterial phylogeny.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Approaches to investigate crop responses to ozone pollution: from O 3 -FACE to satellite-enabled modeling

Ozone (O 3 ) is a damaging air pollutant to crops. As one of the most reactive oxidants known, O 3 rapidly forms other reactive oxygen species (ROS) once it enters leaves through stomata. Those ROS in turn can cause oxidative stress, reduce photosynthesis, accelerate senescence, and decrease crop yield. To improve and adapt our feed, fuel, and food supply to rising O 3 pollution, a number of Free Air Concentration Enrichment (O 3 -FACE) facilities have been developed around the world and have studied key staple crops. In this review, we provide an overview of the FACE facilities and highlight some of the lessons learned from the last two decades of research. We discuss the differences between C 3 and C 4 crop responses to elevated O 3 , the possible trade-off between productivity and protection, genetic variation in O 3 response within and across species, and how we might leverage this observed variation for crop improvement. We also highlight the need to improve understanding of the interaction between rising O 3 pollution and other aspects of climate change, notably drought. Finally, we propose the use of globally modeled O 3 data that are available at increasing spatial and temporal resolutions to expand upon the research conducted at the limited number of global O 3 -FACE facilities.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Summary of the 2014 Sandia V&V Challenge Workshop

A discussion of the five responses to the 2014 Sandia Verification and Validation (V&V) Challenge Problem, presented within this special issue, is provided hereafter. Overviews of the challenge problem workshop, workshop participants, and the problem statement are also included. Brief summations of teams' responses to the challenge problem are provided. Issues that arose throughout the responses that are deemed applicable to the general verification, validation, and uncertainty quantification (VVUQ) community are the main focal point of this paper. The discussion is oriented and organized into big picture comparison of data and model usage, VVUQ activities, and differentiating conceptual themes behind the teams' VVUQ strategies. Significant differences are noted in the teams' approaches toward all VVUQ activities, and those deemed most relevant are discussed. Beyond the specific details of VVUQ implementations, thematic concepts are found to create differences among the approaches; some of the major themes are discussed. Lastly, an encapsulation of the key contributions, the lessons learned, and advice for the future are presented.

42 ENGINEERING↗
DOE OSTI2023

Manufacturing and Hydro Testing of a 10 MWe sCO2 Axial Turbine

Abstract Supercritical CO2 (sCO2) power cycles designed for thermodynamic efficiencies above 50% push component designs into pressure and temperature combinations that approach the limits of American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code and ASME Piping Design Codes with Turbine inlet conditions near 250 bar and 715 °C. These design conditions which limit available materials to high nickel alloys are compounded by the high fluid densities of sCO2 at these conditions which result in very compact machinery at the 10 MWe class which are currently being developed for the DOE supercritical transformational electric power (STEP) program. Design of the STEP Turbine is complete with integrated lessons learned from a previous 1 MWth subscale demonstration of a high temperature 10 MWe Turbine designed under the DOE SunShot Program. Fabrication of the STEP Turbine is nearing completion with all housings and pressure containing components in hand. This paper provides a detailed look at design intentions and limitations for the pressurized sections of the main pressure casing and the fabrication of key turbine components. Additional discussion is provided regarding postfabrication inspection and acceptance of the casing for use after issues with casing welds were identified late in the fabrication process.

Engineering↗
DOE OSTI2017

Surface recogniton for cars: A comprehensive approach for neural networks

This paper explores the viability of neural-networkbased classification of ground surface for vehicles. By classifying road surface in near realtime, improvements in vehicle performance (e.g. braking and cornering) may be possible. Classification performance for many combinations of feature encoding and neural network types are compared. The vehicle used here was an An Audi “S3” with a magnetic suspension system on the sport mode. An NI CompactRIO (or cDAQ) module was used to record from a lowing the cDAQ to communicate with the PCB 352C03 one-axis accelerometer. The accelerometer was firmly attached to the windshield of the car. This work focuses on the classification of four road surfaces (asphalt, dirt, concrete, and sand), though larger target sets were also considered. The most accurate method involved a MATLAB feature extraction package with a back-propagation neural network, yielding an overall accuracy of 97%. Lessons learned from this wide exploration of options may extend to other related classification problems.

33 ADVANCED PROPULSION SYSTEMS↗