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At least 1,045 records · Page 58

Pulse Energy and Pulse Duration Effects in the Ionization and Fragmentation of Iodomethane by Ultraintense Hard X Rays

The interaction of intense femtosecond x-ray pulses with molecules sensitively depends on the interplay between multiple photoabsorptions, Auger decay, charge rearrangement, and nuclear motion. Here, we report on a combined experimental and theoretical study of the ionization and fragmentation of iodomethane (CH 3 I) by ultraintense (~10 19 W/cm 2 ) x-ray pulses at 8.3 keV, demonstrating how these dynamics depend on the x-ray pulse energy and duration. We show that the timing of multiple ionization steps leading to a particular reaction product and, thus, the product’s final kinetic energy, is determined by the pulse duration rather than the pulse energy or intensity. While the overall degree of ionization is mainly defined by the pulse energy, our measurement reveals that the yield of the fragments with the highest charge states is enhanced for short pulse durations, in contrast to earlier observations for atoms and small molecules in the soft x-ray domain. Finally, we attribute this effect to a decreased charge transfer efficiency at larger internuclear separations, which are reached during longer pulses.

36 MATERIALS SCIENCE↗

Simulations of coherent scattering experiments at storage ring synchrotron radiation sources in the hard x-ray range

Detailed simulations of experiments carried out at modern light sources are directly related to the most efficient and productive use of these facilities for research in multiple branches of science and technology. The “Synchrotron Radiation Workshop” computer code with its Python interface, and Sirepo web-browser-based graphical user interface, currently supports physical optics simulations of coherent X-ray scattering and imaging experiments on user-defined virtual samples. We present examples of simulations of coherent scattering experiments that are typically performed at the Coherent Hard X-ray beamline at Brookhaven National Laboratory’s (BNL) National Synchrotron Light Source II. We also present several comparisons of the simulations with the results of actual coherent X-ray scattering experiments with nano-fabricated test samples produced at BNL’s Center for Functional Nanomaterials.

36 MATERIALS SCIENCE↗

Measurement of multi-particle azimuthal correlations in pp, p + Pb and low-multiplicity Pb + Pb collisions with the ATLAS detector

Multi-particle cumulants and corresponding Fourier harmonics are measured for azimuthal angle distributions of charged particles in pp collisions at $\sqrt{s}$ = 5.02 and 13 TeV and in p + Pb collisions at $\sqrt{s}$$_ {NN}$ = 5.02 TeV, and compared to the results obtained for low-multiplicity Pb + Pb collisions at $\sqrt{s}$$_ {NN}$ = 2.76 TeV. These measurements aim to assess the collective nature of particle production. The measurements of multi-particle cumulants confirm the evidence for collective phenomena in p + Pb and low-multiplicity Pb + Pb collisions. On the other hand, the pp results for four-particle cumulants do not demonstrate collective behaviour, indicating that they may be biased by contributions from non-flow correlations. A comparison of multi-particle cumulants and derived Fourier harmonics across different collision systems is presented as a function of the charged-particle multiplicity. For a given multiplicity, the measured Fourier harmonics are largest in Pb + Pb, smaller in p + Pb and smallest in pp collisions. Finally, the pp results show no dependence on the collision energy, nor on the multiplicity.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Preliminary Design of Critical Experiments Involving Commercially Available B 4 C Neutron Absorber Plates with Low-Enriched UO 2 Fuel

The International Criticality Safety Benchmark Evaluation Project (ICSBEP) is an initiative to provide high-quality benchmark data in a standardized format for criticality safety analysts to use to validate calculational tools and nuclear data. In the last released 2022 version, the ICSBEP handbook contains over 5,000 critical experiment descriptions, results, and associated models. This paper describes the critical configurations proposed and calculations performed as part of the conceptual design phase of Integral Experiment Request (IER) 554 (IER-554). The goal of IER-554 is to add to the benchmark experiments available to the criticality safety community by designing critical experiments that can analyze how adding commercially available Boralcan plates to an assembly of low-enriched UO2 fuel rods affects the effective neutron multiplication factor (k eff ). Boralcan, a neutron absorber product developed by Rio Tinto, is made of B4C in an Al 1100 matrix and is commonly used for criticality suppression in fuel storage pools. In the current version of the ICSBEP handbook, only a few dated critical experiments involve B4C materials, and none involve Boralcan in a thin plate shape. The experiments designed as part of IER-554 are intended to be performed at the Sandia Pulsed Reactor Facility/Critical Experiments (SPRF/CX) apparatus at Sandia National Laboratories. SPRF/CX is a well-characterized assembly considered trustworthy by the benchmarking community because of the numerous high-quality evaluations with very low experimental uncertainties included in the ICSBEP handbook. Figure 1 illustrates the assembly for a particular configuration from LCT-078, one of the published benchmarks in the ICSBEP handbook. The experiments will be moderated and reflected by light water at ambient atmospheric pressure. Before the plates are inserted in the critical assembly, they will be characterized with x-ray computed tomography (XCT) to identify the sizes and distribution of the B 4 C powder particles inside the plates. The preliminary design calculations were performed with SCALE 6.3.0 using the KENO V.a sequence for the criticality calculations, the CE-TSUNAMI-3D sequence for the sensitivity and uncertainty studies, and the ENDF/B-VII.1 Continuous Energy cross section library. All the calculation results presented have 10 pcm statistical uncertainties. A set of critical experiments with Boralcan plates could increase the confidence of the criticality safety community in its modeling methods when using this type of neutron absorber material. Experiments would also help validate k eff calculations, and the industry could use these validations to change the B loading credit limits from the US Nuclear Regulatory Commission standard review plan for dry cask storage of spent nuclear fuel. This paper summarizes only part of the analysis documented in the preliminary design report.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Enhancement of STAYSL_PNNL with IRDFF/V1.05 to 60 MeV

The STAYSL PNNL program performs a least-squares adjustment of the neutron spectrum based on the IRDFF cross section library and user-defined activation data and a starting neutron spectrum. All known covariances are included. Required corrections are included for the irradiation history, gamma absorption, neutron burn-up, and neutron self-shielding using separate utility programs prior to the execution of STAYSL PNNL. Several new neutron cross section libraries based on IRDFF V1.05 to 60 MeV are provided with the program including energy group structures of 69 (WIMS), 129 (14 MeV), 140 (prior 100 groups extended to 60 MeV), 175 (Vitamin J), 640 (old SANDII to 20 MeV), and 725 (old Sand II extended to 60 MeV) energy groups. Twelve new reactions were included in IRDFF V1.05. At higher neutron energies, calculations demonstrate the need for activation cross sections from natural targets such as Ti(n,x)46Sc rather than only isotopic targets such as 46Ti(n,p)46Sc and 47Ti(n,x)46Sc. The effects of such reactions increase dramatically with increasing neutron energies and cannot be neglected. Some critical reactions such as 56Fe(n,x)54Mn are not currently included in IRDFF and prevent the use of the 54Fe(n,p)54Mn reaction at higher neutron energies. It is recommended that natural element cross sections be included in future releases of IRDFF for a list of reactions that suffer from reactions on multiple isotopes that lead to the same activation product. Spectral adjustments are illustrated in Be(d,n) thick target neutron fields at deuteron energies of 30 and 40 MeV.

reactor dosimetry, neutron spectral adjustment↗

Time-Resolved Quantitative Measurement of OH HO2 and CH2O in Fuel Oxidation Reactions by High Resolution IR Absorption Spectroscopy.

Combined with a Herriott-type multi-pass slow flow reactor, high-resolution differential direct absorption spectroscopy has been used to probe, in situ and quantitatively, hydroxyl (OH), hydroperoxy (HO 2 ) and formaldehyde (CH 2 O) molecules in fuel oxidation reactions in the reactor, with a time resolution of about 1 micro-second. While OH and CH 2 O are probed in the mid-infrared (MIR) region near 2870nm and 3574nm respectively, HO 2 can be probed in both regions: near-infrared (NIR) at 1509nm and MIR at 2870nm. Typical sensitivities are on the order of 10 10 - 10 11 molecule cm -3 for OH at 2870nm, 10 11 molecule cm -3 for HO 2 at 1509nm, and 10 11 molecule cm -3 for CH 2 O at 3574nm. Measurements of multiple important intermediates (OH and HO 2 ) and product (CH 2 O) facilitate to understand and further validate chemical mechanisms of fuel oxidation chemistry.

Huang, Haifeng↗

3-Port Single-Stage PV & Battery Converter Improves Efficiency and Cost in Combined PV/Battery Systems

Due to impressive cost reductions in recent years, photovoltaic (PV) generation is now able to produce electricity at highly competitive prices, but PV’s inherent intermittency reduces the potential value of this energy. The integration of battery storage with PV will be transformational by increasing the value of solar. Utility scale systems will benefit by firming intermittency including PV ramp smoothing, grid support and load shifting, allowing PV to compete directly with conventional generation. For distributed grid-tied PV adding storage will reduce peak demand utility charges, as well as providing backup power during power grid failures. The largest long term impact of combined PV and battery systems may be for delivering reliable off-grid power to the billions of individuals globally without access to conventional power grids, or for billions more that suffer from daily power outages. PV module costs no longer dominate installed PV system costs. Balance-of-System (BOS) costs including the PV inverter and installation now contribute the majority of installed system costs. Battery costs are also dropping faster than installation and battery power converter systems. In each of these separate systems power converters have become a bottleneck for efficiency, cost and reliability. These bottlenecks are compounded in hybrid power conversion systems that combine separate PV and battery converters. Hybrid power conversion systems have required multiple power converters hardware units and multiple power conversion steps adding to efficiency losses, product and installation costs, and reliability issues. Ideal Power Converters has developed and patented a completely new theory of operation for electronic power converters using its indirect EnergyPacket Switching™ topology. It has established successful power converter products for both PV and battery systems, and its 3-Port Hybrid Converter is the first product to exploit the topology’s capability for the industry’s first single-stage multi-port hybrid power converter. This unique low cost approach eliminates the hybrid power conversion bottlenecks when integrating batteries into PV systems. As result this product will significantly accelerate market adoption of these systems.

14 SOLAR ENERGY↗

Milestone Report - M3FT-15OR03120215 - Recommend HIP Conditions for AgZ

The purpose of this study was to continue research to determine if HIPing could directly convert I-Ag 0 Z into a suitable waste form. Fiscal year (FY) 2015 work completed studies of Phase IIA, IIB, and IIC samples. Product consistency testing (PCT) of Phase IIA samples resulted in iodine release below detection limit for six of twelve samples. This is promising and indicates that a durable waste form may be produced through HIPing even if transformation of the zeolite to a distinct mineral phase does not occur. From PCT results of Phase IIA samples, it was determined that future pressing should be conducted at a temperature of 900°C. Phase IIC testing continued production of samples to examine the effects of multiple source materials, compositional variations, and an expanded temperature range. The density of each sample was determined and x-ray diffraction (XRD) patterns were obtained. In all cases, there was nothing in the XRD analyses to indicate the creation of any AgI-containing silicon phase; the samples were found to be largely amorphous.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

California Power-to-Gas and Power-to-Hydrogen Near-Term Business Case Evaluation

Flexible operation of electrolysis systems represents an opportunity to reduce the cost of hydrogen for a variety of end-uses while also supporting grid operations and thereby enabling greater renewable penetration. California is an ideal location to realize that value on account of growing renewable capacity and markets for hydrogen as a fuel cell electric vehicle (FCEV) fuel, refineries, and other end-uses. Shifting the production of hydrogen to avoid high cost electricity and participation in utility and system operator markets along with installing renewable generation to avoid utility charges and increase revenue from the Low Carbon Fuel Standard (LCFS) program can result in around $2.5/kg (21%) reduction in the production and delivery cost of hydrogen from electrolysis. This reduction can be achieved without impacting the consumers of hydrogen. Additionally, future strategies for reducing hydrogen cost were explored and include lower cost of capital, participation in the Renewable Fuel Standard program, capital cost reduction, and increased LCFS value. Each must be achieved independently and could each contribute to further reductions. Using the assumptions in this study found a 29% reduction in cost if all future strategies are realized. Flexible hydrogen production can simultaneously improve the performance and decarbonize multiple energy sectors. The lessons learned from this study should be used to understand near-term cost drivers and to support longer-term research activities to further improve cost effectiveness of grid integrated electrolysis systems.

33 ADVANCED PROPULSION SYSTEMS↗

Water Availability Indices – A Literature Review

Fresh water is a critical resource for humanity and the ecosystem. In general, water resources can be partitioned into two major categories: blue water and green water (Falkenmark and Rockström 2006). Precipitation that runs off or percolates into the deep aquifer is defined as blue water, and precipitation that filtrates into soil, which eventually returns to the atmosphere as evaporation, is called green water (Hoekstra et al. 2011). For human purposes, green water is almost exclusively used for agricultural production, but blue water can be used for multiple competing sectors, such as irrigation and municipal water.

54 ENVIRONMENTAL SCIENCES↗

California-Specific Power-to-Hydrogen and Power-to-Gas Business Case Evaluation

Flexible operation of electrolysis systems represents an opportunity to reduce the cost of hydrogen for a variety of end-uses while also supporting grid operations and thereby enabling greater renewable penetration. California is an ideal location to realize that value on account of growing renewable capacity and markets for hydrogen as a fuel cell electric vehicle (FCEV) fuel, refineries, and other end-uses. Shifting the production of hydrogen to avoid high cost electricity and participation in utility and system operator markets along with installing renewable generation to avoid utility charges and increase revenue from the Low Carbon Fuel Standard (LCFS) program can result in around $2.5/kg (21%) reduction in the production and delivery cost of hydrogen from electrolysis. This reduction can be achieved without impacting the consumers of hydrogen. Additionally, future strategies for reducing hydrogen cost were explored and include lower cost of capital, participation in the Renewable Fuel Standard program, capital cost reduction, and increased LCFS value. Each must be achieved independently and could each contribute to further reductions. Using the assumptions in this study found a 29% reduction in cost if all future strategies are realized. Flexible hydrogen production can simultaneously improve the performance and decarbonize multiple energy sectors. The lessons learned from this study should be used to understand near-term cost drivers and to support longer-term research activities to further improve cost effectiveness of grid integrated electrolysis systems.

30 DIRECT ENERGY CONVERSION↗

Aerosol and Cloud Optical Properties from the ARM Raman Lidars: The Feature Detection and Extinction (RLPROF-FEX) Value-Added Product

Aerosols and their interactions and influence on clouds are among the main sources of uncertainties in radiative direct and indirect forcing (IPCC 2013). Continuous height-resolved measurements of cloud and aerosol optical properties are needed to reduce these uncertainties. Here we describe the Raman Lidar Profiles – Feature detection and Extinction (RLPROF-FEX) Value-Added Product (VAP) derived using Raman lidar data at multiple U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) user facility sites. RLPROF-FEX provides estimates of extinction, backscatter, and depolarization using the algorithm described by Thorsen et al. 2015 and Thorsen and Fu 2015. This document provides a description of the FEX algorithm, its input and output data, and related details about the Raman lidar (RL) system.

54 ENVIRONMENTAL SCIENCES↗

Image registration using binary boundary maps

Registration technique that matches binary boundary maps extracted from raw data, rather than matching actual data, is considerably faster than other techniques. Boundary maps, which are digital representations of regions where image amplitudes change significantly, typically represent data compression of 60 to 70 percent. Maps allow average products to be computed with addition rather than multiplication, further reducing computation time.

Andrus, J. F.↗

Satellite pattern classification using charge transfer devices

The potential uses of Charge Transfer Devices (CTDs) in pattern classification operations are explored. The needs for a hardware-based pattern classifier are established, and a matrix multiplication subsystem based upon a sum-of-products CTD is presented. Applications of the subsystem to the classification of multi-modal Gaussian distributions in general and to LANDSAT data processing in particular are discussed. Finally, the potential impact of this technology on satellite data processing methodologies is discussed.

Snyder, W. E.↗

Gamma ray observatory productivity showcase

The Gamma Ray Observatory (GRO) Program has been proclaimed to be the showcase productivity program for NASA and TRW. Among the multiple disciplines of a large-scale program, there is opportunity and need for improved efficiency, effectiveness, and reduction in the cost of doing business. The efforts and tools that will or have been implemented to achieve this end are described. Since the GRO Program is mainly an engineering program with the build of one satellite, the primary emphasis is placed on improving the efficiency and quality of management and engineering.

Davis, R. L.↗

Effects of NO3(-) and NH4(+) and urea on each other's uptake and incorporation

The purpose was to determine the optimal use by wheat plants of the N sources expected from processing biological waste products, NO3(-),NO2(-)NH4(+), and urea. The approach was to determine the uptake and metabolic products of each N source (from single and multiple component solutions), inhibitory effects of each, feedback inhibition, and overall in vivo regulation of the rates of assimilation of each by wheat plants. Previously, researchers determined the interactions of NO3(-),NO2(-),NH4(+) on each other's uptake and incorporation. The assimilation and some of its effects on NO3(-) and NH4(+) assimilation which have been completed to data are discussed.

Huffaker, R. C.↗

A model of multigeneration neutrals in cometary comae

The spatial distribution of neutral species in the outer coma of a comet is described using a modified version of the fountain model. This model accounts for neutrals that are produced in multiple generations after release from the nucleus (or production in the collision zone of the inner coma) by an iterative application of the fountain model. A preliminary description of the model is given; however, results are presented in a future paper. Suitable applications of the model include the following: (1) distributed coma sources of neutral gas phase species from anisotropic dust emission; (2) the description of cometary comae at large heliocentric distances; and (3) day/night asymmetry of gas production from the nucleus.

Boice, Dan C.↗

Lunar surface mining for automated acquisition of helium-3: Methods, processes, and equipment

In this paper, several techniques considered for mining and processing the regolith on the lunar surface are presented. These techniques have been proposed and evaluated based primarily on the following criteria: (1) mining operations should be relatively simple; (2) procedures of mineral processing should be few and relatively easy; (3) transferring tonnages of regolith on the Moon should be minimized; (4) operations outside the lunar base should be readily automated; (5) all equipment should be maintainable; and (6) economic benefit should be sufficient for commercial exploitation. The economic benefits are not addressed in this paper; however, the energy benefits have been estimated to be between 250 and 350 times the mining energy. A mobile mining scheme is proposed that meets most of the mining objectives. This concept uses a bucket-wheel excavator for excavating the regolith, several mechanical electrostatic separators for beneficiation of the regolith, a fast-moving fluidized bed reactor to heat the particles, and a palladium diffuser to separate H2 from the other solar wind gases. At the final stage of the miner, the regolith 'tailings' are deposited directly into the ditch behind the miner and cylinders of the valuable solar wind gases are transported to a central gas processing facility. During the production of He-3, large quantities of valuable H2, H2O, CO, CO2, and N2 are produced for utilization at the lunar base. For larger production of He-3 the utilization of multiple-miners is recommended rather than increasing their size. Multiple miners permit operations at more sites and provide redundancy in case of equipment failure.

Li, Y. T.↗