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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Modeling Challenges for Energy Recovery Linacs with Long, High Charge Bunches

Historically, nearly all energy recovery linacs (ERLs) built and operated were used to drive a free-electron laser (FEL). The requirement for high peak current bunches necessitates bunch compression and handling the attendant beam dynamical challenges. In recent years, ERLs have turned from being drivers of light sources toward applications for nuclear physics experiments, Compton backscattering sources and strong electron cooling. Unlike an FEL, these latter uses require long, high charge bunches with small energy spread. The electron bunch must maintain a small projected energy spread and therefore must avoid gross distortion due to CSR and longitudinal space charge over a single (or multiple) recirculations. Accurately modeling the relevant collective effects in the system 'space charge, microbunching instability, CSR and the effect of shielding' in addition to beam dynamical processes such as halo, presents a formidable challenge. Absent a code that models all of these effects, we outline an approach towards the design, analysis and optimization of the high-energy electron cooler for the Jefferson Lab Electron-Ion Collider and survey widely used codes and their capabilities.

Tennant, Christopher D.↗
DOE OSTI2014

Overview of Development and Deployment of Codes, Standards and Regulations Affecting Energy Storage System Safety in the United States

This report acquaints stakeholders and interested parties involved in the development and/or deployment of energy storage systems (ESS) with the subject of safety-related codes, standards and regulations (CSRs). It is hoped that users of this document gain a more in depth and uniform understanding of safety-related CSR development and deployment that can foster improved communications among all ESS stakeholders and the collaboration needed to realize more timely acceptance and approval of safe ESS technology through appropriate CSR.

Conover, David R.↗
DOE OSTI2018

The CBETA Fractional Arc Test

As part of this development effort, the Cornell-BNL Energy recovery linac Test Accelerator (CBETA) [3], a 4-pass, 150 MeV energy recovery linac (ERL), utilizing a Non-scaling Fixed Field Alternating-gradient (NS-FFA) permanent magnet return loop, is currently under design and construction at Cornell University through the joint collaboration of Brookhaven National Lab (BNL) and the Cornell Laboratory for Accelerator based Sciences and Education (CLASSE). Building on the significant advancements in high-brightness photoelectron sources and SRF technology at Cornell, as well as the FFA magnet and lattice design expertise from BNL, CBETA will establish the operation of a multi-turn SRF based ERL utilizing a compact FFA return loop with large energy acceptance (a factor of roughly 3.6 in energy), and thus demonstrate one possible cost-reduction technology under consideration for the eRHIC design. Moreover, successful completion of the CBETA project requires the study and measurement of many critical phenomena relevant to designing the EIC: the Beam-Breakup (BBU) instability, halo-development and collimation, growth in energy spread from Coherent Synchrotron Radiation (CSR), and CSR micro bunching, and thus should provide valuable insight to the EIC and ERL communities. In order to demonstrate the viability of the CBETA design, the Fractional Arc Test (FAT) was added to the CBETA commissioning sequence.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Making Bioweapons Obsolete: A Summary of Workshop Discussions

This report is based on discussions held during an unclassified workshop hosted by Sandia National Laboratories (SNL) and the Council on Strategic Risks (CSR) on August 29, 2019. The first in a planned series, this workshop brought together experts from government, national laboratories, academia, industry, and the policy and entrepreneur communities to examine the potential to use strategy, technology advances, policy, and other tools to make bioweapons obsolete. The workshop provided participants with a rare opportunity to step back from their day-to-day jobs and think strategically about how to achieve this goal more effectively and rapidly. The conversation was held under the Chatham House Rule. The objective was to generate and share ideas and identify questions that will be critical to answer in pursuit of making bioweapons obsolete. Its purpose was not to create consensus. This report does not represent consensus among participants, nor does it assign specific perspectives to any individual participant or represent the official views of any United States (U.S.) government agency or the organizing institutions namely, SNL and CSR.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
NASA NTRS2007

Comparison of Polar Motion Excitation Series Derived from GRACE and from Analyses of Geophysical Fluids

Three sets of degree-2, order-1 harmonics of the gravity field, derived from the Gravity Recovery and Climate Experiment (GRACE) data processed at the Center for Space Research (CSR), Jet Propulsion Laboratory (JPL) and GeoforschungsZentrum (GFZ), are used to compute polar motion excitation functions X1 and X2. The GFZ and JPL excitations and the CSR X2, excitation compare generally well with geodetically observed excitation after removal of effects of oceanic currents and atmospheric winds. The agreement considerably exceeds that from previous GRACE data releases. For the JPL series, levels of correlation with the geodetic observations and the variance explained are comparable to, but still lower than, those obtained independently from available models and analyses of the atmosphere, ocean, and land hydrology. Improvements in data quality of gravity missions are still needed to deliver even tighter constraints on mass-related excitation of polar motion.

Nastula, J.↗
NASA NTRS2012

Sensitivity of Marine Warm Cloud Retrieval Statistics to Algorithm Choices: Examples from MODIS Collection 6

The optical and microphysical structure of warm boundary layer marine clouds is of fundamental importance for understanding a variety of cloud radiation and precipitation processes. With the advent of MODIS (Moderate Resolution Imaging Spectroradiometer) on the NASA EOS Terra and Aqua platforms, simultaneous global/daily 1km retrievals of cloud optical thickness and effective particle size are provided, as well as the derived water path. In addition, the cloud product (MOD06/MYD06 for MODIS Terra and Aqua, respectively) provides separate effective radii results using the l.6, 2.1, and 3.7 ~m spectral channels. Cloud retrieval statistics are highly sensitive to how a pixel identified as being "notclear" by a cloud mask (e.g., the MOD35/MYD35 product) is determined to be useful for an optical retrieval based on a 1-D cloud model. The Collection 5 MODIS retrieval algorithm removed pixels associated with cloud'edges as well as ocean pixels with partly cloudy elements in the 250m MODIS cloud mask - part of the so-called Clear Sky Restoral (CSR) algorithm. Collection 6 attempts retrievals for those two pixel populations, but allows a user to isolate or filter out the populations via CSR pixel-level Quality Assessment (QA) assignments. In this paper, using the preliminary Collection 6 MOD06 product, we present global and regional statistical results of marine warm cloud retrieval sensitivities to the cloud edge and 250m partly cloudy pixel populations. As expected, retrievals for these pixels are generally consistent with a breakdown of the ID cloud model. While optical thickness for these suspect pixel populations may have some utility for radiative studies, the retrievals should be used with extreme caution for process and microphysical studies.

Platnick, Steven↗
NASA NTRS2019

Orion Ascent Abort 2 Test - Benefits of a Digital Collaboration Environment

The Ascent Abort-2 Crew Module and Separation Ring (CSR) were developed internally to NASA, led by the JSC EA Integrated Product Team. The CSR IPT leveraged Sharepoint as an Integrated Data environment to link systems engineering and project management data element, enabling collaborative development and engagement from across the project (NASA-wide). This presentation describes the mission, the development approach, and the benefits of this approach. flight operations

Devolites, Jenny↗
DOE OSTI2015

Control of synchrotron radiation effects during recirculation with bunch compression

Studies of beam quality during recirculation have been extended to an arc providing bunch compression with positive momentum compaction. It controls both incoherent and coherent synchrotron radiation (ISR and CSR) using methods including optics balance and generates little microbunching gain. We detail the dynamical basis for the design, discuss the design process, give an example, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of microbunching effects.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Design of bunch compressing system with suppression of coherent synchrotron radiation for ATF upgrade

One of the operation modes for Accelerator Test Facility (ATF) upgrade is to provide high peak current, high quality electron beam for users. Such operation requires a bunch compressing system with a very large compression ratio. The CSR originating from the strong compressors generally could greatly degrade the quality of the electron beam. In this paper, we present our design for the entire bunch compressing system that will limit the effect of CSR on the e-beam’s quality. We discuss and detail the performance from the start to end simulation of such a compressor for ATF.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Chapter 1: Direct Normal Radiation

This chapter addresses the quantitative and qualitative aspects of the solar resource, the direct solar radiation. It discusses the total or integrated broadband direct beam extraterrestrial radiation (ETR). This total integrated irradiance is comprised of photons of electromagnetic radiation. The chapter also discusses the impact of the atmosphere and its effect upon the direct normal irradiance (DNI) beam radiation. The gases and particulates present in the atmosphere traversed by the direct beam reflect, absorb, and scatter differing spectral regions and proportions of the direct beam, and act as a variable filter. Knowledge of the available broadband DNI beam radiation resource data is essential in designing a concentrating photovoltaic (CPV) system. Spectral variations in the DNI beam radiation affect the performance of a CPV system depending on the solar cell technology used. The chapter describes propagation and scattering processes of circumsolar radiation (CSR), which includes the Mie scattering from large particles.

14 SOLAR ENERGY↗
DOE OSTI2018

Design Principles for Sparse Matrix Multiplication on the GPU

We implement two novel algorithms for sparse-matrix dense-matrix multiplication (SpMM) on the GPU. Our algorithms expect the sparse input in the popular compressed-sparse-row (CSR) format and thus do not require expensive format conversion. While previous SpMM work concentrates on thread-level parallelism, we additionally focus on latency hiding with instruction-level parallelism and load-balancing. We show, both theoretically and experimentally, that the proposed SpMM is a better fit for the GPU than previous approaches. We identify a key memory access pattern that allows efficient access into both input and output matrices that is crucial to getting excellent performance on SpMM. By combining these two ingredients---(i) merge-based load-balancing and (ii) row-major coalesced memory access---we demonstrate a 4.1x peak speedup and a 31.7% geomean speedup over state-of-the-art SpMM implementations on real-world datasets.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

Suppression of Weakly-Damped Torsional Oscillations in Autonomous Power Systems

Variants are considered for suppression of weakly-damped vibration effects caused by the first critical frequency of torsional oscillations of a gas-turbine unit in the autonomous electric power system of an oil and gas field. It is shown that torsional oscillations can be suppressed with the aid both of a reactive power source installed at the field power system, consisting of a controlled shunt reactor (CSR) and a static capacitor battery, and of an auxiliary active RLC filter, when using in both cases auxiliary control loops of torsional deviation as well as its first and second derivatives. A methodology has been developed for simultaneous coordination of the settings of any regulation system based on a numerical optimization, which permits selecting the characteristics of control loops of the source of reactive power and active RLC filter that are optimal from the point of view of suppressing torsional oscillations.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2018

Overexpression of TUSC7 inhibits the inflammation caused by microglia activation via regulating miR-449a/PPAR-γ

Highlights: • The neuropathic pain in cervical spondylotic radiculopathy (CSR) is greatly impact the patient's life and work. • The neuropathic pain is partly caused by the inflammation induced by microglia activation. • Overexpression of TUSC7 inhibited microglial activation and the expression of inflammatory factors. • Overexpression of TUSC7 inhibited the inflammation caused by microglia activation via miR-449a up-regulating PPAR-γ. The aim of this study was to investigate the mechanisms of TUSC7/miR-449a/PPAR-γ axis on the inflammation induced by microglia activation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

High-precision Q EC values of superallowed 0 + → 0 + β-emitters 46 Cr, 50 Fe and 54 Ni

Short-lived 46 Cr, 50 Fe and 54 Ni were studied by isochronous mass spectrometry at the HIRFL-CSR facility in Lanzhou. The measured precision mass excesses (ME) of 46 Cr, 50 Fe and 54 Ni are -29471(11) keV, -34477(6) keV and -39278(4) keV, respectively. The superallowed 0 + →0+β-decay Q values were derived to be Q EC ( 46 Cr) =7604(11) keV, Q EC ( 50 Fe) =8150(6) keV and Q EC ( 54 Ni) =8731(4) keV. The values for 50 Fe and 54 Ni are by one order of magnitude more precise than the adopted literature values. By combining the existing half-lives and branching ratios, we obtained the corrected ℱt values to be ℱt( 50 Fe) =3103(70) s and ℱt( 54 Ni) =3076(50) s. The main contribution to the ℱt uncertainties is now due to β-decay branching ratios, still, more high-precision measurements of the half-lives, the masses, and especially the branching ratios are needed in order to satisfy the requirements for a stringent CVC test.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Direct normal irradiance related definitions and applications: The circumsolar issue

The direct irradiance received on a plane normal to the sun, called direct normal irradiance (DNI), is of particular relevance to concentrated solar technologies, including concentrating solar thermal plants and concentrated photovoltaic systems. Following various standards from the International Organization for Standardization (ISO), the DNI definition is related to the irradiance from a small solid angle of the sky, centered on the position of the sun. Half-angle apertures of pyrheliometers measuring DNI have varied over time, up to ≈10°. The current recommendation of the World Meteorological Organization (WMO) for this half-angle is 2.5°. Solar concentrating collectors have an angular acceptance function that can be significantly narrower, especially for technologies with high concentration ratios. The disagreement between the various interpretations of DNI, from the theoretical definition used in atmospheric physics and radiative transfer modeling to practical definitions corresponding to specific measurements or conversion technologies is significant, especially in the presence of cirrus clouds or large concentration of aerosols. Under such sky conditions, the circumsolar radiation—i.e. the diffuse radiation coming from the vicinity of the sun—contributes significantly to the DNI ground measurement, although some concentrating collectors cannot utilize the bulk of it. These issues have been identified in the EU-funded projects MACC-II (Monitoring Atmospheric Composition and Climate-Interim Implementation) and SFERA (Solar Facilities for the European Research Area), and have been discussed within a panel of international experts in the framework of the Solar Heating and Cooling (SHC) program of the International Energy Agency’s (IEA’s) Task 46 “ Solar Resource Assessment and Forecasting ”. In accordance with these discussions, the terms of reference related to DNI are specified here. The important role of circumsolar radiation is evidenced, and its potential contribution is evaluated for typical atmospheric conditions. Thus, thorough analysis of performance of concentrating solar systems, it is recommended that, in addition to the conventional DNI related to 2.5° half-angle of today’s pyrheliometers, solar resource data sets also report the sunshape, the circumsolar contribution or the circumsolar ratio (CSR).

14 SOLAR ENERGY↗
DOE OSTI2025

Electron recombination of rotationally cold D 2 H + ions

Dissociative recombination (DR) of electrons with small molecular ions is a fundamental process for the physics and chemistry of the interstellar medium and planetary atmospheres. In previous DR studies, detailed analysis of the experimental rate coefficients has been hindered by the difficulty of preparing the ions in well-defined quantum states. For polyatomic ions in particular, truly state-selective measurements have been elusive, allowing only qualitative benchmarks of theory. Here, we present DR studies of the deuterated triatomic hydrogen ion D 2 H + , where the molecular ions were stored for up to 1000 seconds inside the Cryogenic Storage Ring (CSR) prior to the DR measurements. Our experiments with rotationally cold D 2 H + ions allow for detailed comparison to state-of-the-art theoretical calculations. We obtain very good agreement between experiment and theory even in the important collision energy range from 1 meV to 0.5 eV, where a multitude of Rydberg resonances reveal their imprint on the rate coefficient.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Predicting the liquefaction phenomena from shear velocity profiling: Empirical approach to 6.3 Mw, May 2006 Yogyakarta earthquake

The liquefactions phenomena have been reported after a shocking 6.5Mw earthquake hit Yogyakarta province in the morning at 27 May 2006. Several researchers have reported the damage, casualties, and soil failure due to the quake, including the mapping and analyzing the liquefaction phenomena. Most of them based on SPT test. The study try to draw the liquefaction susceptibility by means the shear velocity profiling using modified Multichannel Analysis of Surface Waves (MASW). This paper is a preliminary report by using only several measured MASW points. The study built 8-channel seismic data logger with 4.5 Hz geophones for this purpose. Several different offsets used to record the high and low frequencies of surface waves. The phase-velocity diagrams were stacked in the frequency domain rather than in time domain, for a clearer and easier dispersion curve picking. All codes are implementing in Matlab. From these procedures, shear velocity profiling was collected beneath each geophone’s spread. By mapping the minimum depth of shallow water table, calculating PGA with soil classification, using empirical formula for saturated soil weight from shear velocity profile, and calculating CRR and CSR at every depth, the liquefaction characteristic can be identify in every layer. From several acquired data, a liquefiable potential at some depth below water table was obtained.

58 GEOSCIENCES↗