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At least 91 records · Page 5

Joint Inversion of Regional Waveform, First-Motion Polarity, and Synthetic Aperture Radar Surface Displacement for the Fourth and Sixth North Korean Declared Nuclear Explosions

Here, this study analyzed the Democratic People’s Republic of Korea’s (DPRK) fourth (DPRK4, 6 January 2016 M w 4.49) and sixth (DPRK6, 7 September 2017 M w 5.2) declared nuclear tests, employing a joint seismic and Interferometric Synthetic Aperture Radar (InSAR) inversion to improve understanding of these events and enhance moment tensor (MT) inversion capabilities. The recent efforts have focused on employing seismic waveform and InSAR geodetic deformation data separately to analyze these and the previous nuclear tests (e.g., Chiang et al., 2018; Myers et al., 2018; Wang et al., 2018). Building upon our previous work (Chi-Durán et al., 2021), we performed a joint regional waveform, first-motion (FM) polarity, and surface displacement inversion, which demonstrated improved source-type discrimination, a revised MT solution with reduced scalar moment uncertainty, and an independently constrained location. In this article, we build on the previous results for DPRK6 by including an analysis using a four-layered velocity model with free-surface topography to compute the near-source static deformation Green’s functions. The model consists of a 50 m basalt layer (⁠V P = 2.07 km/s, V S = 1.2 km/s⁠), a 250 m stratified volcanic deposit layer (⁠V P = 1.73 km/s, V S = 1.0 km/s⁠), a 700 m weathered granodiorite layer (⁠V P = 2.5 km/s, V S = 1.3 km/s⁠⁠), and a granodiorite half-space (⁠V P = 5.35 km/s, V S = 3.09 km/s⁠⁠). The half-space shares the velocity of the regional MDJ2 velocity model (Ford et al., 2010), which has proven effective for waveform inversion in the region. This model considers the range of reported values for various lithologies and weathering effects. Our findings show that using the layered velocity model enhances the recovery of source location and depth for both the explosions by improving fits and reducing uncertainties. The joint inversion also improves source-type discrimination and better constrains the scalar seismic moment necessary for downstream yield estimation.

58 GEOSCIENCES↗

Rapid Determination of Uranium Isotopic Abundance from Cotton Swipes: Direct Extraction via a Planar Surface Reader and Coupling to a Microplasma Ionization Source

The collection of solid particulates and liquids from surfaces by the use of cloth swipes is fairly ubiquitous. In such methods, there is a continuous concern regarding the ability to locate and quantitatively sample the analyte species from the material. In this effort, we demonstrate the initial coupling of an Advion Plate Express plate reader to a liquid sampling–atmospheric pressure glow discharge (LS-APGD) microplasma ionization source with an Orbitrap mass spectrometer to perform uranium isotopic analyses of solution residues on cotton swipes. The Plate Express employs a sampling probe head to engage and seal against the swipe surface. Subsequentially, the analyte residues are desorbed and transported within a 2% HNO 3 electrolyte flow to the ionization source. Quantitative recoveries were observed following a single 30 s extraction step, with the absolute mass sampled per extraction being ~100 ng. While the intrasample variability in the analytical responses for triplicate sampling of the same swipe yield ~30% RSD, this lack of precision is offset by the ability to determine isotope ratios for enriched uranium specimens with a precision of better than 10% RSD. Pooled, intersample precision ( n = 9) was found to be <5%RSD across the various sample compositions. Finally, 235 U/ 238 U determinations (ranging from 0.053 to 1.806) were accurate with errors of <10%, absolute. The 234 U- and 236 U-inclusive ratios were determined with similar accuracy in enriched samples. While the driving force for the effort is in the realm of nuclear nonproliferation efforts, the ubiquitous use of cloth swipes across many application areas could benefit from this convenient approach, including the use of versatile, reduced-format mass spectrometer systems.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

Waste heat recovery from the European Spallation Source cryogenic helium plants - implications for system design

The European Spallation Source (ESS) neutron spallation project currently being designed will be built outside of Lund, Sweden. The ESS design includes three helium cryoplants, providing cryogenic cooling for the proton accelerator superconducting cavities, the target neutron source, and for the ESS instrument suite. In total, the cryoplants consume approximately 7 MW of electrical power, and will produce approximately 36 kW of refrigeration at temperatures ranging from 2-16 K. Most of the power consumed by the cryoplants ends up as waste heat, which must be rejected. One hallmark of the ESS design is the goal to recycle waste heat from ESS to the city of Lund district heating system. The design of the cooling system must optimize the delivery of waste heat from ESS to the district heating system and also assure the efficient operation of ESS systems. This report outlines the cooling scheme for the ESS cryoplants, and examines the effect of the cooling system design on cryoplant design, availability and operation.

43 PARTICLE ACCELERATORS↗

Final Report: Development of a CW NCRF Photoinjector using Solid Freeform Fabrication

The development of very high duty cycle, high gradient photoinjectors is critical for the next generation of accelerator systems, such as X-ray free-electron lasers (FELs), inverse Compton scattering (ICS) sources, energy recovery linacs (ERLs), injectors for linear colliders, as well as a variety of industrial systems for homeland security applications. NCRF photoinjectors have a proven track record at generating the high-quality beams necessary for these applications, however they are limited in large part to relatively low duty cycles due to ohmic wall looses. Thus a key issue for high average power, normal conducting, photoinjectors is effective structure cooling [9]. The fabrication of current high average-power photoinjectors relies on conventional design and fabrication techniques with many limitations. Advances in Solid Freeform Fabrication (SFF) technology may make it possible to design and produce near net-shape copper structures for the next generation of very high rep rate, high gradient radio frequency (RF) photoinjectors. RF and thermal-management optimized geometries could be fully realized without the usual constraints and compromises of conventional machining techniques*. Further advances in SFF and powder metallurgy (P/M) techniques, with the ability to fine tune material properties, may soon make it possible to produce monolithic, thermally robust RF structures faster and cheaper than ever before.

Frigola, Pedro↗

Photocathode Research for Electron Accelerators

This dissertation presents studies of two different types of photocathodes used at electron accelerators: GaAs and K2CsSb. The spin polarization of photoelectrons extracted from GaAs photocathodes was evaluated using traditional one-photon absorption and two-photon absorption, to determine the validity of speculation that two-photon absorption would provide significantly higher polarization. To accomplish this study, a novel compact, retarding-field Mott polarimeter was designed, built and commissioned. The second type of photocathode, K2CsSb, was manufactured at Brookhaven National Laboratory and transported to Jefferson Lab in an ultrahigh vacuum "suitcase" and installed within a DC high voltage gun. Charge lifetime measurements were made using a K2CsSb photocathode and compared to those of GaAs under identical operating conditions. The surface morphology of the used K2CsSb was also studied. Many important atomic, nuclear and high energy physics experiments rely on using highly spin-polarized electron beams obtained via photoemission from GaAs photocathodes. Remarkably, even after 30 years of GaAs photogun operation, there are still some lingering questions associated with the beam polarization values being lower than expected. Bulk GaAs can theoretically provide 50% polarization but typically provides ~ 35%. Reduced polarization is attributed to a number of proposed depolarization mechanisms. Recently, it was proposed that two-photon absorption could be exploited to selectively populate the conduction band with electrons of just one spin state providing 100% polarization. These claims were refuted by others on theoretical grounds. In this thesis, for the first time, two-photon photoemission was demonstrated with beam delivered to a novel polarimeter constructed for this experiment. Polarization was found to be comparable to that obtained with conventional one-photon absorption, and to converge to the same value with a reduction in thickness of the active layer, thereby providing additional experimental insight to the polarized photoemission process an depolarization mechanisms in GaAs. Many proposed accelerators (light sources, energy recovery linacs and electron cooling machines) require extremely high average beam current (~ 100mA). The highest average current accelerator today, the FEL at JLab, can operate at up to 10mA and relies on photoemission from GaAs, even though spin polarization is not required. GaAs is an extremely delicate material, prone to failure and requiring ultrahigh vacuum conditions. In the early 1990s, the multi-alkali photocathode K2CsSb was used to demonstrate 32mA average current inside an RF gun with poor vacuum characteristics. This experiment lasted just minutes and was terminated shortly after the high current milestone was met. Based on this early work, many people believe K2CsSb represents a much better photocathode choice for unpolarized accelerator applications, providing high current for long periods of time and under less stringent operating conditions, but a detailed comparative study using the same apparatus has not been done. To address the high current reliability issue, two K2CsSb photocathodes were manufactured at Brookhaven National Lab and transported to Jefferson Lab via an ultrahigh vacuum transport chamber. They were installed within a 200kV DC high voltage photogun. Systematic charge lifetime measurements were performed using both photocathode materials under identical conditions. The performance of K2CsSb was shown to be highly dependent on extracted current. By combining this decay behavior with surface science measurements of the used photocathodes, it was shown that heat quickly disrupts the capability of the K2CsSb photocathode.

McCarter, James↗

Operational Experience with the Nb/Pb SRF Photoelectron Gun

SRF photoelectron guns offer the promise of high brightness, high average current beam production for the next generation of accelerator driven light sources such as free electron lasers, THz radiation sources or energy-recovery linac driven synchrotron radiation sources. In a first step a fully superconducting RF (SRF) photoelectron gun is under development by a collaboration between HZB, DESY, JLAB, BNL and NCBJ. The aim of the experiment is to understand and improve the performance of a Nb SRF gun cavity coated with a small metallic Pb cathode film on the cavity backplane. This paper describes the highlights from the commissioning and beam parameter measurements. The main focus is on lessons learned from operation of the SRF gun.

43 PARTICLE ACCELERATORS↗

Enhancement of a Process Flowsheet for Recovering and Concentrating Critical Materials from Bituminous Coal Sources

Recovery of rare earth elements (REE) from coal-related resources has recently received significant interest due to supply concerns and their key roles in critical industries and defense-related technologies. In this study, an integrated flowsheet consisting of sorting, crushing/grinding, physical separation, acid leaching, solvent extraction, and selective precipitation was designed to achieve continuous production of rare earth products from various coal-related resources such as coarse refuse and acid mine drainage. A pilot plant was constructed that enabled continuous testing of the circuitry on a range of different coal-based feedstocks. Despite achieving significant success in producing high-grade rare earth oxide products, low REE recovery values and high operational costs necessitated a re-evaluation of the process flowsheet. This article describes the circuitry improvements that were based on both laboratory and pilot plant test results. Roasting as a pre-leach treatment was found to significantly improve the leaching rate and overall REE recovery values. After roasting West Kentucky No. 13 and Fire Clay coal refuse materials at 600 °C, REE recovery increased by 60 and 40 absolute percentage points, respectively. Rare earth concentration in the pregnant leachate solution (PLS) was increased to around 700 ppm prior to solvent extraction using a staged precipitation method. REEs in the precipitate were re-dissolved, purified, and extracted from the PLS using solvent extraction and selective precipitation to values of around 80%. As a result of the improvements, chemical consumption in the acid leaching and solvent extraction processes was significantly reduced. A techno-economical assessment of the improved flowsheet indicated significant commercialization potential.

01 COAL, LIGNITE, AND PEAT↗

Ion collector design for an energy recovery test proposal with the negative ion source NIO1

Commercial viability of thermonuclear fusion power plants depends also on minimizing the recirculation power used to operate the reactor. The neutral beam injector (NBI) remains one of the most important method for plasma heating and control. For the future fusion power plant project DEMO, a NBI wall plug efficiency at least of 0.45 is required, while efficiency of present NBI project is about 0.25. The D{sup −} beam from a negative ion source is partially neutralized by a gas cell, which leaves more than 40% of energy in residual beams (D{sup −} and D{sup +}), so that an ion beam energy recovery system can significantly contribute to optimize efficiency. Recently, the test negative ion source NIO1 (60 keV, 9 beamlets with 15 mA H{sup −} each) has been designed and built at RFX (Padua) for negative ion production efficiency and the beam quality optimization. In this paper, a study proposal to use the NIO1 source also for a beam energy recovery test experiment is presented and a preliminary design of a negative ion beam collector with simulations of beam energy recovery is discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Evaluation of trace elements in U.S. coals using the USGS COALQUAL database version 3.0. Part I: Rare earth elements and yttrium (REY)

Coal is a potential source of valuable elements such as rare earth elements and yttrium (REY). In this work, REY concentrations in U.S. domestic coals were evaluated using data from the USGS COALQUAL Database Version 3.0. The database contains a total of 7657 non-weathered, full-bed coal samples. The number of samples containing REY data points varies among elements. Assessment of data quality indicates that some of the REY data are semi-quantitative and should be used with caution. Different analytical instruments and methods with varying accuracies and precisions are thought to be the main sources of errors. Inclusion of qualified data also accounts for the sawtooth pattern of the UCC-normalized REY distribution. A new set of Q factor values was thus proposed to adjust qualified data. Consequently, mean concentrations of REY in U.S. coals were obtained with a total REY concentration of 65.5 ppm on a moisture-free whole coal basis. Further evaluation of REY in 5378 selected coal samples indicates that about 9–13% of the samples fall into the combined category of promising and highly promising coals for REY, according to the classification of Dai et al. (2017). Taking sampling bias into consideration, we further found that bituminous coal, particularly from the central Appalachian region, has the highest probability of being a source for beneficial recovery of REY. More specifically, bituminous coal from eastern Kentucky is likely to be the best option. Lastly, we conclude that U.S. domestic coal is a promising, alternative source for beneficial recovery of REY to meet the U.S. REY demand for economic growth.

01 COAL, LIGNITE, AND PEAT↗

Parametric study of an acid baking process for rare earth element recovery from a bituminous-coal source

Acid baking treatment is widely used to extract rare earth elements (REEs) from refractory rare earth bearing minerals such as monazite and xenotime. Since these REE minerals have been identified in coal-based sources, a parametric study was conducted to evaluate the impact and optimize the parametric values associated with the acid-baking process when treating a bituminous coal source. The parameters studied using a three-level statistical experimental program were acid baking time, acid solution concentration, baking temperature, and acid solution-to-solids ratio and each were found to significantly impact REE and contaminant element recovery. An increase in baking temperature up to around 250°C improved the light and heavy REE recovery values by more than 50 absolute percentage points relative to performances achieved when direct leaching. Acid baking was needed to dehydroxylate the clays and liberate the REE minerals, which allowed access for the acid to solubilize the REEs. Acid concentration of the solution used for acid baking was studied as a means of minimizing the amount of acid needed to achieve a target REE recovery. However, thermo-gravimetric and differential scanning calorimetry analysis (TGA-DSC) of sulfuric acid under oxidizing atmosphere revealed that the addition of water decreased the evaporation temperature, which explains the lower REE recovery values obtained when using lower acid concentrations. Using pure sulfuric acid at an acid-to-solid ratio of 0.8:1 resulted in recovery values of around 70% for both LREEs and HREEs. The decomposition reaction time was relatively quick with 65% of the TREEs recovered within the first 10 minutes. Water leaching experiments performed on the acid-baked products under a temperature of 25°C instead of 75°C revealed an increase in REE recovery by 10 absolute percentage points, which was likely due to the high solubility of REE-sulfates at room temperatures.

01 COAL, LIGNITE, AND PEAT↗

Tritium Recycling from Depleted Uranium Beds - 18098

Nuclear Sources and Services Inc. (NSSI) in Houston Texas houses a unique infrastructure to recover and recycle tritium from a variety of different waste streams. NSSI is licensed to operate within a 2-gram tritium inventory limit and accepts gaseous, aqueous, and tritiated-solid feedstock as sources for tritium recovery. For example, titanium-tritide foils from spent neutron generator sources are de-tritiated at 1000 deg. C in a high temperature desorption facility. Tritiated water is concentrated in a Combined Electrolysis Catalytic Exchange (CECE) system before the gas is transferred to a hydrogen isotope separator for tritium recovery. Mixed-waste liquids containing tritium and carbon-14 isotopes, typically generated in the pharmaceutical industry, are converted to tritiated water, CaC14O3, and inactive gaseous effluents using a high-temperature, two-stage, catalytic-oxidation destruction process with 99.9999% efficiency. [1-4] Depleted uranium (DU) beds are unloaded of tritium and chemically de-activated with oxygen in the bed unloading station. Recently NSSI has worked with the EPA to receive and unload tritium from a number of legacy DU beds found at a super fund site. The DU beds were un-characterized and ranged from 10 to 30 years in age. The variety and size of the beds meant that measuring the quantity of tritium by calorimetry would be prohibitively expensive. Ground disposal was problematic due to the unknown tritium inventory in the beds and the pyrophoricity of the depleted uranium. NSSI was able to unload the tritium from a representative sample of two DU beds, collect and measure the total activity of the gas destined for recycling and remove the hazardous material codes of the DU by de-activating the bed with oxygen before disposing them as low active waste. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

A systematic analytical framework for multi-source municipal solid waste characterization for energy recovery

Advancing municipal solid waste (MSW) management from disposal-oriented practices toward circular, value-driven systems requires standardized methodologies capable of identifying material composition and resource recoverable potential at the point of generation. Despite extensive research, MSW characterization remains fragmented due to inconsistences in sampling methodologies, waste sorting categories, and temporal coverage across previous studies which limit cross-site comparability, reproducibility, and constrain the reliable evaluation of potential resource recovery pathways. This lack of consistency has hindered the development of a unified framework for MSW characterization and resource assessment. This study introduces a standardized, field-validated protocol for MSW sampling and composition analysis that ensures consistent, traceable data across diverse waste sources. The protocol integrates randomized spatial sampling, systematic material sorting, and controlled subsampling for multi-site and multi-season field campaigns. Validation included MSW collection from residential, grocery, restaurant, and school MSW streams across five U.S. states, including Maryland, Idaho, Virginia, Ohio, and Mississippi, to demonstrate the protocol’s ability to identify source-based composition patterns relevant to resource recovery applications. Grocery and restaurant streams were dominated by food waste and high-moisture organics, while school waste contained higher paper content and residential waste showed greater heterogeneity. Aggregation into energy-relevant fractions highlighted practical recovery pathways via anaerobic digestion or gasification, supporting data-driven planning, policy, and circular economy strategies for sustainable waste management across waste sources.

09 BIOMASS FUELS↗

Risk-Aware Measurement Synchronization and Recovery for DSSE With Heterogeneous Data Sources

Power distribution systems are increasingly integrating heterogeneous sensors with varying data reporting rates and types, which pose challenges to achieving observability at the desired temporal resolution of distribution system state estimation (DSSE). Multisensor failures caused by extreme events exacerbate these issues, introducing substantial uncertainties into DSSE. This article proposes a novel solution to these challenges by ensuring high-resolution system observability despite heterogeneous data sources and multisensor failures. First, a deep learning architecture combining long short-term memory (LSTM) and graph convolutional network (GCN) is employed to synchronize meters with different reporting rates, aiming to achieve system observability. A random-walk-model-based approach is introduced to generate pseudo-measurements while properly characterizing their uncertainties under multisensor failures. Finally, a disaster-risk-informed observability metric (RiOM) is defined to quantify the uncertainty associated with state estimation results. The proposed framework offers deeper insights into the system observability on the fly compared with conventional analysis. The effectiveness of the framework is demonstrated on an IEEE standard test case and a large-scale real-world distribution feeder in mid-Minnesota in the U.S.

97 MATHEMATICS AND COMPUTING↗

Recovery Act - Geothermal Technologies Program: Ground Source Heat Pumps Final Scientific/Technical Report

A large centralized geothermal heat pump system was installed to provide ice making, space cooling, space heating, process water heating, and domestic hot water heating for an ice arena in Eagan Minnesota. This paper provides information related to the design and construction of the project. Additionally, operating conditions for 12 months after start-up are provided.

15 GEOTHERMAL ENERGY↗

A synthetic Roman Space Telescope High-Latitude Time-Domain Survey: supernovae in the deep field

ABSTRACT NASA will launch the Nancy Grace Roman Space Telescope (hereafter Roman) in the second half of this decade, which will allow for a generation-defining measurement of dark energy through multiple probes, including Type Ia supernovae (SNe Ia). To improve decisions on survey strategy, we have created the first simulations of realistic Roman images that include artificial SNe Ia injected as point sources in the images. Our analysis combines work done on Roman simulations for weak gravitational lensing studies as well as catalogue-level simulations of SN Ia samples. We have created a time series of images over 2 yr containing ∼1050 SNe Ia, covering a 1 deg2 subarea of a planned 5 deg2 deep survey. We have released these images publicly for community use along with input catalogues of all injected sources. We create secondary products from these images by generating coadded images and demonstrating recovery of transient sources using image subtraction. We perform first-use analyses on these images in order to measure galaxy detection efficiency, point source detection efficiency, and host-galaxy association biases. The simulated images can be found here at https://roman.ipac.caltech.edu/sims/SN_Survey_Image_sim.html.

Astronomy & Astrophysics↗

Service area size assessment for evaluating the spatial scale of solid waste recovery chains: A territorial perspective

Highlights: • A model to evaluate the service area size of a waste recovery chain is proposed. • A recovery performance score is given per waste source. •The areas to be collected in priority are the sources with the highest score. • The score depends on the source's characteristics and the recovery technology. •Replacing anaerobic digestion by composting decreases the facility's spatial scale. - Abstract: Waste recovery is an integrated part of municipal solid waste management systems but its strategic planning is still challenging. In particular, the service area size of facilities is a sensitive issue since its calculation depends on various factors related to treatment technologies (output products) and territorial features (sources waste production and location). This work presents a systemic approach for the estimation of a chain's service area size, based on a balance between costs and recovery profits. The model assigns a recovery performance value to each source, which can be positive, neutral or negative. If it is positive, the source should be included in the facility's service area. Applied to the case of Montreal for food waste recovery by anaerobic digestion, the approach showed that at most 23 out of the 30 districts should be included in the service area, depending on the indicator, which represents around 127,000 t of waste recovered/year. Due to the systemic approach, these districts were not necessarily the closest to the facility. Moreover, for the Montreal case, changing the facility's location did not have a great influence on the optimal service area size, showing that the distance to the facility was not a decisive factor at this scale. However, replacing anaerobic digestion by a composting plant reduced the break-even transport distances and, thus, the number of sources worth collecting (around 68,500 t/year). In this way, the methodology, applied to different management strategies, gave a sense of the spatial dynamics involved in the recovery chain's design. The map of optimal supply obtained could be used to further analyse the feasibility of multi-site and/or multi-technology systems for the territory considered.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Operation and Process Control Development for a Pilot-Scale Leaching and Solvent Extraction Circuit Recovering Rare Earth Elements from Coal-Based Sources

The US Department of Energy in 2010 has identified several rare earth elements as critical materials to clean technologies. As part of ongoing research in REEs recovery from coal sources, the University of Kentucky has designed, developed and is demonstrating a ¼ ton/hour pilot-scale processing plant to produce high grade REEs from coal sources. To accomplish process control, PLC systems design/deployment, overall operational design and the utilization of Six Sigma design methodology by the team will be presented. Furthermore, application of the controls design, both procedural and electronic, team’s utilization of data analysis and integration for database decision-making will be discussed.

Leaching↗