Search Results (945)

High-purity quartz processing currently faces three critical factors: depleting reserves of high-grade natural ore, inadequate impurity removal efficiency, and heavy environmental pollution driven by traditional refining methods. Therefore, this article first introduces the reasons for the formation of different types of impurities in quartz, as well as the methods and difficulties in removing different types of impurities. Then, a comprehensive summary was made of the current research progress and purification mechanism of quartz purification technology. The study of acid leaching kinetics in quartz purification can accurately determine the optimal operating parameters and support process scaling up. Calcination treatment has been verified to achieve efficient impurity removal. Specifically, the phase transformation and vacuum calcination behaviors during thermal treatment dominate the impurity elimination mechanism. Correspondingly, targeted and efficient purification strategies are proposed to remove different categories of impurities. The future quartz purification holds strong potential in several key areas. These include optical sorting, microwave-assisted calcination furnaces, biological surfactants, and fluoride-free acid leaching. Additional high-potential directions involve rapid macroscopic identification methods for quartz ore and the extraction of quartz from solid waste. Full article

This study presents a comprehensive experimental and theoretical investigation into dual-gate field-emission devices fabricated using a standard 0.35 µm CMOS-MEMS process. Two emitter configurations, the concave-tip and triangular-tip, are characterized, and their performance is rigorously analyzed using three-dimensional simulations based on Fowler–Nordheim emission theory. To account for discrepancies between initial designs and fabricated devices, the influence of critical geometric parameters, including tip apex radius, cathode-anode spacing, and tip sharpness, is systematically evaluated regarding emission current and threshold voltage. Compared to the floating-gate baseline (~38 V), dual-gate (DG) operation lowers the threshold voltage by ~70% (~10 V), enhances low-voltage emission over tenfold, and provides a 3.4-fold boost in differential output conductance. Simulation analysis indicates this improvement stems from enhanced electrostatic field distribution governed by the gates. Furthermore, the top gate, due to its proximity to the emitter tip relative to the bottom gate, provides superior control over emission current at lower operating voltages. Three-dimensional simulations corroborate these findings, revealing that minimizing both the tip radius and cathode-anode spacing substantially enhances tunneling electron flow. Additionally, gate voltage sweeps confirm that electron trajectories are effectively directed by electrostatic steering. These findings establish critical design guidelines for integrating field-emission devices into standard CMOS platforms, facilitating the development of on-chip electrostatically controlled electron sources for integrated vacuum microelectronics. Full article

The formulation of Quantum Field Theory (QFT) in phase space offers a unique alternative to operator and path-integral paradigms, providing distinct conceptual advantages for semiclassical expansions. In this work, we present a systematic and self-consistent functional framework that maps stationary Schrodinger functional equations directly onto phase-space star-eigenvalue equations across different spin statistics. Operating within a non-manifestly covariant equal-time formalism, we derive explicit vacuum Wigner functionals for scalar, gauge, and fermionic fields, establishing the rigorous theoretical consistency of the formalism from first principles prior to phenomenological applications. We analyze how ordering prescriptions and continuous symmetries manifest under the functional star-product, including an explicit phase-space formulation of Noether’s theorem and field regularization. Finally, the framework is extended to interacting systems via a functional Rayleigh–Schrodinger perturbative scheme, illustrated explicitly through the non-trivial first-order Wigner functional correction $W^{\left(1\right)}$ and the vacuum energy correction for a ${\varphi }^4$ self-interacting theory, establishing a solid foundation for evaluating real-time quantum field dynamics. Full article

The use of non-certified commercial electronics for cryogenic applications may be attractive due to their reduced cost and high availability, but they also carry risks related to reliability, performance, and thermal compatibility. The decision to use commercial components that are not certified for cryogenics instead of components specifically designed for such applications must be carefully weighed based on specific project needs and risk tolerances. This work presents the characterisation of a Low-Noise Amplifier (LNA) at cryogenic temperatures for use in astronomical instrumentation applications with a microwave kinetic inductance detector (MKID) readout system. The cooling system comprises a cryostat, a cold head operating in a closed-cycle helium refrigeration system based on the Gifford–McMahon principle, a compressor, connectors, cables, a vacuum pump, pressure and temperature sensors, and a temperature control system. The circuit was characterised over the temperature range of 295.4 K to 78.3 K. Full article

Anode materials play a pivotal role in a wide range of electrochemical applications, including electrolysis, energy storage, corrosion protection, and industrial oxidation processes. This review provides a comprehensive analysis of recent advances in anode materials, with particular emphasis on their structural characteristics and major preparation methods, including thermal decomposition, electrochemical deposition, sol–gel processing, and magnetron sputtering. The degradation behaviour of anodes under electrochemical operating conditions is also critically discussed, together with strategies for improving their durability and overall performance. Particular attention is given to metal oxide-coated anodes, especially those based on ruthenium oxide (RuO₂) and iridium oxide (IrO₂), which remain the most representative systems in dimensionally stable anode (DSA) research and industrial applications. Emerging coating materials, including Co₃O₄- and carbon-based catalysts, are also reviewed as promising alternatives for reducing noble metal usage while maintaining acceptable electrochemical performance. In addition, the role of intermediate layers in titanium-based anodes is examined, with emphasis on their contribution to coating adhesion, conductivity, interfacial stability, and long-term electrode performance. This review further discusses the applications of anode materials in chlorine- and oxygen-related electrochemical industries and evaluates the performance of DSAs in relation to substrate selection, coating composition, and operational requirements. Alternative furnace technologies for anode baking are also reviewed, including conventional furnace heating, laser heating, and microwave heating, together with representative industrial furnace systems such as muffle, continuous, and vacuum furnaces. Overall, this review provides an integrated overview of the current progress in anode material research and development, while highlighting the key challenges and future directions for improving anode efficiency, durability, and sustainability in industrial electrochemical applications. Full article

Background: People who inject drugs (PWID) comprise the majority of patients with native tricuspid valve (TV) infective endocarditis (IE). Many patients require surgical repair or replacement of their TV, but some may be deemed ineligible for surgical management due to high operative risk or patient preference. Vacuum-assisted percutaneous mechanical aspiration (PMA) has emerged as a potential alternative to surgical management in this population. The objective of this study was to describe real-world patient characteristics and clinical outcomes in PWID who underwent PMA or surgical management of TV IE. Methods: We retrospectively reviewed PWID hospitalized with endocarditis at a single tertiary care center (2016–2025) who underwent an isolated PMA or surgical TV repair/replacement (TVR). Baseline demographic, clinical, microbiologic, and echocardiographic characteristics were described. Clinical outcomes were compared descriptively between groups, recognizing imbalances in treatment selection. Results: A total of 40 PWID met inclusion criteria; 17 underwent PMA and 23 underwent surgical TVR. There was substantial baseline clinical heterogeneity between the two groups. Procedural success was numerically higher with surgery than with PMA (95.7% vs. 88.2%). Clinical success, a composite of procedural success, treatment completion, and lack of need for reintervention, was numerically higher in the TVR group (73.9% vs. 52.9%). One-year mortality was similar between groups. Conclusions: In this single-center retrospective observational cohort of PWID with isolated TV IE, there was no statistical difference in composite clinical or procedural success between patients who underwent PMA or TVR. PMA may be a feasible source-control strategy for select patients not eligible for immediate surgery; however, larger prospective studies are needed to define optimal patient selection factors and comparative effectiveness. Full article

This study presents an integrated framework for developing kinetic models of vacuum gas oil (VGO) catalytic cracking under sparse experimental data conditions. Experiments were performed in the CREC Riser Simulator at different C/O (catalyst/VGO) weight ratios. The CREC Riser Simulator is a bench-scale mini-fluidized reactor capable of reproducing the short contact times and operating conditions of industrial fluid catalytic cracking (FCC) risers. Product distributions were characterized by using a five-lump scheme consisting of unconverted VGO, light cycle oil (LCO), gasoline, light gases, and coke. To address the limitations associated with sparse datasets, a feedforward neural network (FNN) was used to reconstruct continuous reaction trajectories from discrete experimental measurements. These synthetic trajectories enabled the estimation of kinetic parameters for a phenomenological five-lump reaction network that incorporates catalyst deactivation. The resulting kinetic model established was subsequently implemented in a 1D heterogeneous model of a large-scale industrial FCC riser, providing reliable predictions of VGO conversion, product selectivity, and axial temperature profiles. Full article

Recovering nitrogen from wastewater is vital for a circular economy, yet conventional air stripping is limited by aerodynamic backpressure and CO₂-induced pH drops. This study evaluates a novel pilot-scale engineering approach for municipal reject water, integrating chemical phosphorus precipitation with a fundamentally redesigned ammonia stripping column. Upstream calcium hydroxide dosing achieved >99.9% phosphorus recovery and spontaneously alkalized the effluent (pH > 12.1), eliminating supplementary caustic addition. The downstream stripping column utilized negative-pressure (vacuum) operation and high-pressure liquid atomization to maximize mass transfer while preventing flooding and alkalinity neutralization. Comprehensive on-site testing established a clear mathematical relationship between aerodynamics and efficiency. Results demonstrate that high-efficiency recovery requires gas-to-liquid (G/L) ratios exceeding 70:1, a threshold uniquely unlocked by this negative-pressure design. Under optimal conditions, the continuous-flow system achieved 87.6% ammonia removal. A low-resistance acid scrubber captured ~100% of the volatilized ammonia (exhaust 0–1 ppm), producing a concentrated ammonium sulfate bio-fertilizer. This integrated technology provides a scalable, applied engineering blueprint for advancing sustainable Water Resource Recovery Facilities. Full article

In air-suction maize precision seed metering, the power transmission and vacuum air supply are typically routed through separate, non-coaxial paths. This conventional layout leaves transmission components exposed to debris clogging, subjects the seed-metering disc to eccentric torque, and causes non-uniform suction pressure distribution, ultimately degrading seeding consistency. To address these issues, this study proposes a coaxial integrated design in which a servo motor offset from the seed-metering axis drives a hollow rotary support, and the drive output shares the same axis with the central air passage. Bench tests showed that motor-end feedback speed entered the final target-speed ±5% band within 8.0–36.6 ms, with maximum overshoot of 0.15–5.76%. Seed-disc pre-filling reduced the mean unseeded distance at start-up from 83.1 to 10.4 cm (87.5%, p < 0.001). Field verification at target spacings of 15 and 20 cm and measured speeds of 3.0–12.0 km/h produced quality-of-feed indices of 91.74–97.50%. The results demonstrate the functional implementation and operational feasibility of the proposed electric-drive system under the tested conditions. Full article

Background: Sclerosing adenosis (SA) is a benign, proliferative breast lesion that frequently mimics malignancy on multimodality imaging. The appropriate clinical management of SA diagnosed via core needle biopsy (CNB) remains a highly debated topic in breast oncology. This study aimed to evaluate the clinical, imaging, and histopathological characteristics of CNB-diagnosed SA-spectrum lesions and to determine the rate of, and factors associated with, pathological upgrade at the time of surgical excision in a symptomatic cohort. Methods: This retrospective, single-center study evaluated 34 symptomatic female patients who received a CNB diagnosis of SA. Patients were assessed using targeted ultrasound (US, n = 34), digital mammography (n = 19), and/or dynamic contrast-enhanced breast MRI (n = 17). Based on CNB findings, lesions were classified as isolated SA, complex/accompanied SA, or atypical SA. Patients subsequently underwent either definitive surgical excision or long-term imaging surveillance. Upgrades were defined as the presence of a high-risk B3 lesion not identified on CNB (Level 1) or overt malignancy, such as ductal carcinoma in situ or invasive carcinoma (Level 2), at final surgical pathology. Results: Twenty-one patients (61.8%) underwent surgical excision, while thirteen (38.2%) were managed with radiological follow-up (median surveillance 16 months, range 7–84). Within the surgical cohort, 9 of 21 patients (42.9%; 95% CI: 24.5–63.5%) demonstrated an upgrade: 6 (28.6%; 95% CI: 13.8–50.0%) to a B3-level lesion and 3 (14.3%; 95% CI: 5.0–34.6%) to malignancy. Notably, two of the three malignant upgrades originated from lesions initially classified as isolated SA without atypia on CNB. Due to the limited sample size, no single clinical or imaging variable (BI-RADS category, lesion size, or age) reached statistical significance as an independent predictor of upgrade (all p > 0.10). All patients managed with imaging surveillance remained radiologically stable. Conclusions: In stark contrast to the 1–2% upgrade rates traditionally reported in asymptomatic screening populations, symptomatic SA-spectrum lesions selected for surgical excision following CNB exhibited a substantially higher overall upgrade rate (42.9%) and malignant upgrade rate (14.3%) in our cohort, albeit with wide confidence intervals reflecting the modest surgical subgroup size. The occurrence of malignant upgrades from presumed isolated SA underscores the limitations of CNB sampling and highlights the necessity of multimodality imaging–pathology concordance. Because this estimate derives exclusively from patients already selected for surgery on the basis of clinical and imaging suspicion, it reflects the upgrade risk of this pre-selected, imaging-discordant subgroup and should not be extrapolated to the baseline risk of all CNB-diagnosed SA. Accordingly, these findings caution against extending non-operative management without further scrutiny to symptomatic SA cases showing a similar degree of imaging–pathology discordance: in such cohorts, surgical excision or large-volume vacuum-assisted excision may still merit consideration despite the absence of atypia on CNB, although this observation is drawn from a small, non-randomly selected surgical subgroup and should be interpreted with corresponding caution. Full article

This paper presents the results of a low-cost environmental testing campaign performed on commercial off-the-shelf components intended for aerospace applications, specifically a housekeeping system designed for suborbital launchers. These tests encompass a broader range of thermal and mechanical testing procedures than is typically reported in the literature, providing a more comprehensive assessment of the system’s robustness. The housekeeping system is subjected to sine-equivalent dynamic loads representative of launch environments expected by vehicles such as Ariane 6, VEGA, and Falcon 9 using a shaker. In addition, thermal vacuum testing is conducted to evaluate system performance under temperature and pressure conditions representative of high-altitude flight. Following each test, the system’s functionality is assessed by comparing its performance against baseline laboratory conditions using telemetry data acquired by the system; most importantly, a critical failure on telemetry data acquisition is verified, which determines the survivability of the system. The successful completion of these environmental tests demonstrates the survivability of the housekeeping system, validating its reliability and suitability for operation in suborbital launcher missions. Full article

High-voltage vacuum circuit breakers are critical switching devices in power systems, and their reliable condition assessment is essential for safe operation and maintenance decision-making. However, breaker abnormalities are often reflected by heterogeneous operation-related evidence, and existing methods based on single-source measurements or generic feature fusion may weaken source-specific diagnostic roles and limit the recognition of compound abnormal conditions. To address this problem, this paper proposes the Physics-Guided Multi-Source State Assessment Network (PMSA-Net), a reliability-aware framework that integrates mechanical motion, opening- and closing-position limit events, and infrared thermography. Source-specific encoders first extract dynamic, end-position, and thermal representations. Reliability-aware Asymmetric Selective Interaction (RASI) then calibrates primary and auxiliary evidence, using mechanical motion as the operational context and the other sources as complementary constraints. Thermal Frequency-aware Selective Modulation (TFSM) stabilizes the low-frequency thermal field and enhances high-frequency hotspot responses. Task-conditioned evidence allocation jointly predicts state category, travel anomaly, limit-event consistency, thermal risk, and overall risk. On a laboratory-simulated benchmark covering 15 operating conditions, PMSA-Net achieved $90.18\pm 0.36\%$ state-category accuracy and an $80.00\pm 0.50\%$ overall-risk macro-F1 score over five independent runs. Under cross-source abnormalities, it exceeded the variational-fusion baseline by 2.59 and 3.05 percentage points on these metrics, respectively. These results indicate that reliability-aware calibration improves multi-task assessment of compound breaker abnormalities. Full article

Gas-filled detectors, especially Geiger-Muller (GM) counters, are prone to lost readings due to the dead-time phenomenon. An improved understanding and prediction of GM dead-time behaviour could aid in understanding detector ageing and in developing further compensation methods for inaccurate measurements. To better explore how GM operating conditions influence dead-time, the feasibility of a customizable gas-filled detector apparatus was evaluated. The design allowed for the changing of gas characteristics within the detector and featured accessible and alterable electronics. Apparatus sub-systems worked nominally on their own. However, limitations in drawing a vacuum below 26 kPaa within the detector tube prevented the acquisition of radiation interaction data. Despite this, all sub-systems behaved in explainable manners when interfaced together. Limitations in the drawing of a vacuum lay externally to the design, indicating relative success. Feasibility could not be conclusively determined, though information useful to the future success of such a project was gathered and presented. Feasibility was explored for a pure argon gas system, and successful pressures were estimated to be in the 0.5–2 kPaa range based on external data. Physical evaluation of this successful range could not be performed due to the limitations in drawing a vacuum. Full article

With the advancement of industrial IoT and artificial intelligence technologies, bearing maintenance is gradually evolving toward predictive maintenance. For large bearings, the internal grease must be replaced promptly once it has deteriorated. As the core lubrication component of such bearings, the suction and discharge device directly determines the efficiency of grease discharge and the operational stability of the bearing. To address the issue of insufficient intake capacity in existing units, this study employs the Herschel–Bulkley non-Newtonian fluid model to analyze intake characteristics and conduct multi-parameter co-optimization, revealing the underlying mechanisms by which vacuum level, grease temperature, and the chamfer structure of the grease inlet pipe influence suction performance. Based on the yield stress and shear thinning characteristics of the grease, the flow equation for the inlet section was derived, and the analytical and CFD results showed consistent trends. With the volumetric flow rate in the inlet section as the optimization objective, a multi-parameter co-optimization of the vacuum level, temperature, and chamfer radius was conducted through orthogonal experiments. The results show that under the optimal parameter combination, the inlet volumetric flow rate was significantly increased, and grease supply stability was markedly improved. The research findings provide a theoretical basis and engineering reference for the design optimization of the suction and discharge device for wind turbine bearings. Full article

Thin sections are fundamental tools in mineralogy, petrography, archaeometry, paleontology, and heritage science, allowing for the microscopic study of mineral assemblages, rock textures, ceramic fabrics, and fossil microstructures. Although thin-section preparation is often presented as a standardized technical procedure, the quality and interpretative reliability of the final section depend strongly on material behavior, laboratory equipment, bonding and thinning procedures, thickness-control criteria, and operator decisions made during preparation. This paper examines thin-section preparation as a process of methodological calibration, understood as the material-specific adjustment of preparation decisions in order to preserve the microstructural features required for subsequent interpretation. The study combines an overview of current preparation practice with documented hands-on workflows from academic and heritage-oriented thin-section laboratories. Two case studies are used to develop the calibration framework. The first concerns silicified fossil wood and marly carbonate samples prepared at the Department of Geology, University of Patras, Greece, using water-cooled cutting, epoxy bonding under heat and pressure, machine-assisted and manual thinning, micrometer-based thickness monitoring, and optical assessment adapted to carbonate-rich samples. The second concerns archaeological ceramics, fossiliferous limestone, oolitic limestone, and coherent lithic/sedimentary samples prepared at the INSTAP Study Center for East Crete, Greece, where preparation decisions included mounting-face selection, cleaning, vacuum impregnation where required, controlled lapping, and transmitted/polarized-light quality assessment. Together, the case studies show that equivalent preparation stages require different operational decisions according to hardness, brittleness, porosity, cohesion, fossil content, ceramic fabric, and intended analytical purpose. Preparation-induced features such as microcracks, smearing, surface relief, detachment, or loss of weak fabrics may be misread as primary geological, technological, taphonomic, or conservation-related features if preparation choices are not properly considered. Framed in this way, thin-section preparation is positioned as a foundational first step in heritage material characterization, on which the reliability of subsequent optical, electron-optical, and microanalytical methods directly depends. Full article