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At least 865 records · Page 48

End-to-end jet classification of boosted top quarks with the CMS open data

Here we describe a novel application of the end-to-end deep learning technique to the task of discriminating top quark-initiated jets from those originating from the hadronization of a light quark or a gluon. The end-to-end deep learning technique uses low-level detector representation of high-energy collision event as inputs to deep learning algorithms. In this study, we use low-level detector information from the simulated Compact Muon Solenoid (CMS) open data samples to construct the top jet classifiers. To optimize classifier performance we progressively add low-level information from the CMS tracking detector, including pixel detector reconstructed hits and impact parameters, and demonstrate the value of additional tracking information even when no new spatial structures are added. Relying only on calorimeter energy deposits and reconstructed pixel detector hits, the end-to-end classifier achieves an area under the receiver operator curve (AUC) score of 0.975 ± 0.002 for the task of classifying boosted top quark jets. After adding derived track quantities, the classifier AUC score increases to 0.9824 ± 0.0013, serving as the first performance benchmark for these CMS open data samples.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Real-time elemental analysis of liquids for process monitoring using laser-induced breakdown spectroscopy with a liquid wheel sampling approach

This article presents an engineered sampling system that used a rotating wheel to form a thin liquid layer, permitting the use of laser-induced breakdown spectroscopy (LIBS) for in situ, real-time elemental impurity quantification during liquid processing. The sampling approach was demonstrated on eight elements from across the periodic table (Na, Al, K, Ca, Ti, Sr, Mo, and Yb). Univariate and multivariate calibrations were presented for each element. The average value for percent root mean square errors of cross-validation for the multivariate models was 3.64%, highlighting the method's strong prediction accuracy. Additionally, the limits of detection for each analyte were estimated from their univariate models: Na = 0.0532, Al = 18.5, K = 0.105, Ca = 0.273, Ti = 67.7, Sr = 0.640, Mo = 22.4, and Yb = 22.9 μg mL –1 . Finally, a test in which multivariate models were used to monitor a liquid system for 80 min was performed to investigate the real-time monitoring capabilities of this liquid LIBS sampling approach. Rigorous measurements were performed to effectively predict the absence and concentrations of multiple analytes as they were spiked and diluted. This demonstration showed the feasibility of using LIBS for real-time liquid quantification models with estimated precision ≤ 8.1%. Finally, the limitations of this approach and potential future improvements are discussed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Synthesis routes to eliminate oxide impurity segregation and their influence on intergrain connectivity in K-doped BaFe 2 As 2 polycrystalline bulks

The poor reproducibility of intergrain critical current density $J_c$ in Fe-based superconductors is often believed to result from uncontrolled grain boundary (GB) connectivity degraded by extrinsic factors such as the local or global impurity concentration or GB porosity or cracks. Earlier we found that Ba and K can appear as oxide impurities at GBs, along with GB-wetting FeAs. In this study, we evaluated how the sample preparation environment and purity of the starting materials influence the polycrystalline $J_c$ in K-doped BaFe 2 As 2 (Ba122) bulks. Using a high-performance glovebox, the oxygen and water levels were significantly reduced, eliminating traces of FeAs. We report oxide impurities and Ba (or K) segregation associated with oxygen in the starting materials were significantly reduced by using high purity starting materials. This combination essentially doubled the best $J_c$(4.2 K) values to 2.3 × 10 5 at self-field and 1.6 × 10 4 A cm –2 at 10 T and analytical scanning transmission electron microscopy showed no GB or O segregation in the best samples, but did show dark Z-contrast and distinct nanoscale porosity. Our work shows that an inert synthesis environment and high purity K and Ba do reduce current-blocking oxygen impurity and GB impurity phases, allowing deeper exploration of the role of extrinsic and intrinsic GB blocking effects in controlling the $J_c$ of polycrystalline Ba122.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Extraction of Value-Added Products from Food Processing Waste Using Dimethyl Ether

Poster for 2024 Intern Poster Session. Food production waste can be valorized to create a circular economy. Traditional extraction methods require pretreatment of the sample through heating or cell disruption, but this contributes to a majority of the process's energy usage for wet biomass. Using dimethyl ether extraction can combine the dewatering and extraction processes into one to skip the pretreatment step while still maintaining similar extraction rates.

09 BIOMASS FUELS↗

Elastic Modulus Measurement at High Temperatures for Miniature Ceramic Samples Using Laser Micro-Machining and Thermal Mechanical Analyzer

In this paper, we demonstrate a method of measuring the flexural elastic modulus of ceramics at an intermediate (~millimeter) scale at high temperatures. We used a picosecond laser to precisely cut microbeams from the location of interest in a bulk ceramic. They had a cross-section of approximately 100 μm × 300 μm and a length of ~1 cm. They were then tested in a thermal mechanical analyzer at room temperature, 500 °C, 800 °C, and 1100 °C using the four-point flexural testing method. We compared the elastic moduli of high-purity Al2O3 and AlN measured by our method with the reported values in the literature and found that the difference was less than 5% for both materials. This paper provides a new and accurate method of characterizing the high-temperature elastic modulus of miniature samples extracted from representative/selected areas of bulk materials.

Chemistry↗

Exceedance Response Action (ERA) Level 1 Report and ERA Level 2 Action Plan

This report consolidates the requirements for an Exceedance Response Action (ERA) Level 1 and ERA Level 2 Action Plan for pH. A discharger’s baseline status for any given parameter changes to Level 1 status if sampling results indicate a Numeric Action Level (NAL) exceedance for that same parameter. NAL exceedance can be either of the following: (1) Instantaneous maximum NAL exceedance: Occurs when two or more analytical results for any single parameter within a reporting year exceed the instantaneous maximum NAL (for example for pH a value less than 6 or a value greater than 9); and (2) Annual NAL exceedance: Occurs when the average of all the analytical results for a parameter within a reporting year exceeds the annual NAL. A Discharger’s Level 1 status for any given parameter changes to Level 2 status if sampling results indicate a Numeric Action Level (NAL) exceedance for the same parameter while a Discharger is in Level 1.

54 ENVIRONMENTAL SCIENCES↗

On the Prediction of Uniaxial Tensile Behavior Beyond the Yield Point of Wrought and Additively Manufactured Ti-6Al-4V

In this paper, phenomenological relationships are presented that permit the prediction of the plastic regime of stress–strain curves using a limited number of parameters. These relationships were obtained from both conventional (wrought + β annealed) and additively manufactured (i.e., “3D printed”) Ti-6Al-4V. Three different methods of additive manufacturing have been exploited to produce the materials, including large-volume electron beam additive manufacturing, large-volume laser hot wire additive manufacturing, and small-volume selective laser melting. The general fundamental expressions are independent not only of the additive manufacturing process, but also of a wide variety of post-deposition heat treatments, however the coefficients are specific to material states. Thus, this work demonstrates that it is possible to predict not only the ultimate tensile strength, but also the full true stress, true strain curves, if certain parameters of the material are known. In general, the prediction of ultimate tensile strength are within 5% of the experimentally measured values across all additive manufacturing variants and subsequent heat treatments. The absolute values of ultimate tensile strength range from ~ 910 MPa to ~ 1170 MPa for the single alloy Ti-6Al-4V. Data representing 113 explicit samples are included in this work.

36 MATERIALS SCIENCE↗

Nuclear data for reactor production of 131 Ba and 133 Ba

The newest radioisotope for brachytherapy treatment of prostate cancer is 131 Cs (t 1/2 = 9.69 d, 100% EC). Generated via electron capture decay of 131 Ba (t 1/2 = 11.6 d, 100% EC), 131 Cs has been used in brachytherapy for prostate cancer since 2004. The 131 Ba parent is produced through neutron capture of enriched 130 Ba in a nuclear reactor. For large-scale production of 131 Ba, an accurate knowledge of production and burnup cross sections of 131 Ba are essential. Here, we report two group cross sections (thermal and resonance integrals) for 130 Ba and 131 Ba and a new measure of the half-life of 131 Ba. Targets consisting of milligram quantities of enriched 130Ba (~35%) were irradiated in Oak Ridge National Laboratory's High Flux Isotope Reactor at thermal and resonance neutron fluxes of (1.9–2.1) × 10 15 and (5.8–7.0) × 10 13 neutrons·cm -2 s -1 , respectively, for durations ranging from 3 to 26 days. In addition, cadmium covered samples of 130 Ba were irradiated for 1 hour at 12.6% full reactor power (10.7 MW). The yield of 131 Ba approaches a saturation value of ~60 GBq (~1.6 Ci) per mg of 130 Ba for 20 days irradiation at a thermal neutron flux of 1.8 × 10 15 n·s -1 ·cm -2 , with a thermal/epithermal ratio of ~30. Under the above experimental conditions, the two group cross sections of 130 Ba are 6.9 ± 0.5 b (thermal, σ 0 ) and 173 ± 7 b (resonance, I 0 ). These values represent the sum of cross sections to metastable and ground states of 131 Ba. For 131 Ba, the empirically measured thermal cross section is 200 ± 50 b assuming an I 0 /σ 0 of 10. This cross section is reported for the first time. Further, the half-life of 131 Ba was remeasured to be 11.657 ± 0.008 d. Lastly, this study also resulted in the co-production of 133 Ba (t 1/2 = 10.52 y, 100% EC). The experimental yield of 133 Ba is ~370 MBq (~10 mCi) per mg of 132 Ba (thin target) for one cycle irradiation in the High Flux Isotope Reactor, and measured two-group 132 Ba cross sections are 7.2 ± 0.2 b and 39.9 ± 1.3 b. These values also represent the sum of cross sections to metastable and ground states of 133 Ba.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Benchmarking image processing techniques for porosity measurement in polymer additive manufacturing: Review and experimental analysis

An image processing workflow is proposed for porosity measurement in polymer additive manufacturing. Various techniques, including global and local thresholding, region growing, and K-means clustering, were applied to microscopic images of carbon fiber reinforced acrylonitrile butadiene styrene (CF-ABS) and benchmarked for their ability to accurately measure porosity. Global methods included Otsu, minimum error, iterative, and entropy-based thresholding, while local methods included Niblack, Bernsen, Sauvola, and Bradley-Roth algorithms. Artificial uneven illumination was introduced to test local adaptive thresholds. Results showed significant differences in porosity values across methods. Otsu, region growing, and K-means clustering excelled under uniform illumination, while Sauvola and Bradley-Roth performed better with uneven illumination. Comparison with X-ray computed tomography (XCT) revealed slightly lower porosity values (2.55 %) than optimized methods (2.73–2.79 %) due to XCT's lower resolution excluding smaller pores. While XCT offers finer pore detection, it limits sample volume and underestimates porosity due to spatial variation. Validation using artificial grayscale images with 5 % porosity confirmed that Otsu, Bradley-Roth, region growing, and Sauvola algorithms produced accurate results. Although tested on a single material system, these methods can be adapted to others with optimization. In conclusion, given XCT's high computational and time costs, this study highlights suitable image processing techniques as cost-effective alternatives for porosity analysis in polymer composites.

Additive manufacturing↗

Intrinsic and extrinsic effects on the fracture toughness of ductile metallic glasses

The potential application of metallic glasses (MGs) as structural materials demands accurate measurements of their toughness and the understanding of the underlying factors affecting it. Currently, it is challenging to precisely measure the toughness of MGs, especially ductile MGs. Measured toughness values are widely scattered, even for MGs with identical compositions. That is attributed to the combined effect of intrinsic and extrinsic factors including processing, sample geometries, and loading conditions. A fundamental understanding of the influences of these elements is thus of great significance. In the present study, molecular dynamics simulations are performed to investigate the influence of intrinsic and extrinsic effects on the fracture toughness of CuZr MGs. In particular, focused is placed on the effects of cooling rate, notch shape and size, strain rate, and temperature. The results indicate that the fracture toughness of a MG scales with the cooling rate used to prepare it. This is attributed to increased free volume content generated at high cooling rates, which enhances plastic deformation and amplifies the associated energy dissipation during plastic deformation events. Fracture toughness also increases with the strain rate, arguably due to strain rate-induced crack extension delay. Overall, the results demonstrate that the largest fracture toughness are achieved when MG samples are fabricated at high cooling rates and subjected to high strain rate deformation. In addition, results suggest that the fracture toughness decreases with increasing temperature, due to the significant decrease in strength. Here, the correlations revealed between these crucial intrinsic and extrinsic parameters and the calculated MG fracture toughness support the development of a framework to understand the root of the discrepancies in the measurement of the toughness of MGs and provide insights into the design of tough MGs for structural applications.

36 MATERIALS SCIENCE↗

The Baghdad Atlas: A relational database of inelastic neutron-scattering (n,n ' γ) data

A relational database has been developed based on the original (n,n'γ) work carried out by A. M. Demidov et al., at the Nuclear Research Institute in Baghdad, Iraq (Demidov et al., 1978) for 105 independent measurements comprising 76 elemental samples of natural composition and 29 isotopically-enriched samples. The information from this Atlas includes: γ-ray energies and relative intensities; nuclide and level data corresponding to the residual nucleus and meta data associated with the target sample that allows for the extraction of the flux-weighted (n,n'γ) cross sections for a given transition relative to a defined value. The optimized angular-distribution-corrected fast-neutron flux-weighted partial γ-ray cross section for the production of the 846.8-keV 21+→0gs+γ-ray transition in 56Fe, determined to be $\langle$σγ$\rangle$=143(29) mb, is used for this purpose. However, different values for the adopted cross section can be readily implemented to accommodate user preference based on revised determinations of this quantity. The Atlas (n,n'γ) data has been compiled into a series of CSV-style ASCII data sets and a suite of Python scripts have been developed to build and install the database locally. The database can then be accessed directly through the SQLite engine, or using alternative methods such as the Jupyter Notebook Python-browser interface. Several examples exploiting different interaction methodologies are distributed with the complete software package.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Debottlenecking 4-hydroxybenzoate hydroxylation in Pseudomonas putida KT2440 improves muconate productivity from p -coumarate

The transformation of 4-hydroxybenzoate (4-HBA) to protocatechuate (PCA) is catalyzed by flavoprotein oxygenases known as para-hydroxybenzoate-3-hydroxylases (PHBHs). In Pseudomonas putida KT2440 (P. putida) strains engineered to convert lignin-related aromatic compounds to muconic acid (MA), PHBH activity is rate-limiting, as indicated by the accumulation of 4-HBA, which ultimately limits MA productivity. Here, we hypothesized that replacement of PobA, the native P. putida PHBH, with PraI, a PHBH from Paenibacillus sp. JJ-1b with a broader nicotinamide cofactor preference, could alleviate this bottleneck. Biochemical assays confirmed the strict preference of NADPH for PobA, while PraI can utilize either NADH or NADPH. Kinetic assays demonstrated that both PobA and PraI can utilize NADPH with comparable catalytic efficiency and that PraI also efficiently utilizes NADH at roughly half the catalytic efficiency. The X-ray crystal structure of PraI was solved and revealed absolute conservation of the active site architecture to other PHBH structures despite their differing cofactor preferences. To understand the effect in vivo, we compared three P. putida strains engineered to produce MA from p-coumarate (pCA), showing that expression of praI leads to lower 4-HBA accumulation and decreased NADP+/NADPH ratios relative to strains harboring pobA, indicative of a relieved 4-HBA bottleneck due to increased NADPH availability. In bioreactor cultivations, a strain exclusively expressing praI achieved a titer of 40 g/L MA at 100% molar yield and a productivity of 0.5 g/L/h. Altogether, this study demonstrates the benefit of sampling readily available natural enzyme diversity for debottlenecking metabolic flux in an engineered strain for microbial conversion of lignin-derived compounds to value-added products.

09 BIOMASS FUELS↗

The Chandra view of the relation between X-ray and UV emission in quasars

Here, we present a study of the relation between X-rays and ultraviolet emission in quasars for a sample of broad-line, radio-quiet objects obtained from the cross-match of the Sloan Digital Sky Survey DR14 with the latest Chandra Source Catalog 2.0 (2332 quasars) and the Chandra COSMOS Legacy survey (273 quasars). The non-linear relation between the ultraviolet (at 2500 Å, L UV ) and the X-ray (at 2 keV, L X ) emission in quasars has been proved to be characterised by a smaller intrinsic dispersion than the observed one, as long as a homogeneous selection, aimed at preventing the inclusion of contaminants in the sample, is fulfilled. By leveraging on the low background of Chandra, we performed a complete spectral analysis of all the data available for the SDSS-CSC2.0 quasar sample (i.e. 3430 X-ray observations), with the main goal of reducing the uncertainties on the source properties (e.g. flux, spectral slope). We analysed whether any evolution of the L X – L UV relation exists by dividing the sample in narrow redshift intervals across the redshift range spanned by our sample, z ≃ 0.5–4. We find that the slope of the relation does not evolve with redshift and it is consistent with the literature value of 0.6 over the explored redshift range, implying that the mechanism underlying the coupling of the accretion disc and hot corona is the same at the different cosmic epochs. We also find that the dispersion decreases when examining the highest redshifts, where only pointed observations are available. These results further confirm that quasars are ‘standardisable candles’, that is we can reliably measure cosmological distances at high redshifts where very few cosmological probes are available.

79 ASTRONOMY AND ASTROPHYSICS↗

Thermal conductivity of rutile germanium dioxide

Power electronics seek to improve power conversion of devices by utilizing materials with a wide bandgap, high carrier mobility, and high thermal conductivity. Due to its wide bandgap of 4.5 eV, b-Ga 2 O 3 has received much attention for high-voltage electronic device research. However, it suffers from inefficient thermal conduction that originates from its low-symmetry crystal structure. Rutile germanium oxide (r-GeO 2 ) has been identified as an alternative ultra-wide-bandgap (4.68 eV) semiconductor with predicted high electron mobility and ambipolar dopability; however, its thermal conductivity is unknown. Here, we characterize the thermal conductivity of r-GeO 2 as a function of temperature by first-principles calculations, experimental synthesis, and thermal characterization. The calculations predict an anisotropic phonon-limited thermal conductivity for r-GeO 2 of 37W m –1 K –1 along the a direction and 58W m –1 K –1 along the c direction at 300K where the phonon-limited thermal conductivity predominantly occurs via the acoustic modes. Experimentally, we measured the value of 51W m –1 K –1 at 300K for hot-pressed, polycrystalline r-GeO2 pellets. The measured value is close to our directionally averaged theoretical value, and the temperature dependence of ~1/T is also consistent with our theory prediction, indicating that thermal transport in our r-GeO 2 samples at room temperature and above is governed by phonon scattering. Furthermore, our results reveal that high-symmetry UWBG materials, such as r-GeO 2 , may be the key to efficient power electronics.

36 MATERIALS SCIENCE↗

Metallic hydrogen: Study of metastability

Metallic hydrogen (MH) has been predicted to be metastable, a high temperature superconductor, and a powerful rocket propellant. If true, MH could have an enormous impact on society. We have produced MH in a diamond anvil cell and studied its metastability. At a temperature of 5 K, the load on the metallic hydrogen was stepwise reduced until the pressure was essentially zero. While turning the load or pressure down, the sample evidently transformed to the molecular phase and escaped; the hole in the gasket containing the MH closed. We were unable to determine this value of the metastability pressure. Metallic hydrogen was not observed to be metastable at zero pressure, with no uncertainty.

36 MATERIALS SCIENCE↗

Deep inference of simulated strong lenses in ground-based surveys

The large number of strong lenses discoverable in future astronomical surveys will likely enhance the value of strong gravitational lensing as a cosmic probe of dark energy and dark matter. However, leveraging the increased statistical power of such large samples will require further development of automated lens modeling techniques. We show that deep learning and simulation-based inference (SBI) methods produce informative and reliable estimates of parameter posteriors for strong lensing systems in ground-based surveys. We present the examination and comparison of two approaches to lens parameter estimation for strong galaxy-galaxy lenses — Neural Posterior Estimation (NPE) and Bayesian Neural Networks (BNNs). We perform inference on 1-, 5-, and 12-parameter lens models for ground-based imaging data that mimics the Dark Energy Survey (DES). We find that NPE outperforms BNNs, producing posterior distributions that are more accurate, precise, and well-calibrated for most parameters. For the 12-parameter NPE model, the calibration is consistently within <10% of optimal calibration for all parameters, while the BNN is rarely within 20% of optimal calibration for any of the parameters. Similarly, residuals for most of the parameters are smaller (by up to an order of magnitude) with the NPE model than the BNN model. This work takes important steps in the systematic comparison of methods for different levels of model complexity.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

High-Precision Zinc Isotopic Measurement of Certified Reference Materials Relevant to the Environmental, Earth, Planetary and Biomedical Sciences

The zinc (Zn) stable isotope system has emerged as a powerful tool for investigating natural and anthropogenic processes of interest to disciplines extending from the Earth and planetary sciences to biomedical research. In nature, Zn isotopes typically fractionate ( 66 Zn/ 64 Zn) within the range of –1 and +1 permil (‰), and however, analytical limitations restrict the application of the Zn isotope system. Specifically, there is a lack of well-characterised matrix-matched reference materials covering most Zn isotope applications that are essential for validating laboratory performance, particularly given the contamination prone nature of Zn. Furthermore, the increasing demand for analysis of size-limited materials and sample types displaying small, sub-permil level Zn isotope variations requires improvements in measurement procedures. To address these limitations, the δ 66 Zn values of two pure Zn solutions and eighteen reference materials including the previously uncharacterised RGM-2, BCR-279, DOLT-4, DOLT-5, NASS-7, SBC-1, SGR-1b, MESS-3 and HISS-1, and the understudied QLO-1, SDC-1, BCR-414, NASS-6 and COQ-1 materials are reported. Furthermore, a 70 Zn- 67 Zn double-spike design has been implemented that routinely achieves intermediate measurement precision better than ± 0.02‰. This represents at least a two-fold improvement when compared with other double-spike designs, providing a robust platform of δ 66 Zn values required for quality control procedures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗