Search Results (4,057)

The (1−x)Ba_0.96Ca_0.04TiO₃−xBi(Li_1/3Zr_2/3)O₃ (x = 0.03–0.15) ceramics were fabricated via the traditional solid reaction method. Characterization results revealed that each component exhibited a pure perovskite structure, and the average grain size significantly diminishes with increasing x. The (1−x)Ba_0.96Ca_0.04TiO₃−xBi(Li_1/3Zr_2/3)O₃ ceramics exhibited prominent relaxor ferroelectric behavior, whose characteristic narrow hysteresis loops effectively enhanced the energy storage performance of the material. Most importantly, the composition with x = 0.10 demonstrated exceptional energy storage properties at 150 kV/cm, achieving a high recoverable energy storage density (W_rec = 1.91 J/cm³) and excellent energy efficiency (η = 90.87%). Under the equivalent electric field, this composition also displayed a superior pulsed discharge performance, including a high current density (871 A/cm²), a high power density (67.3 MW/cm³), an ultrafast discharge time (t_0.9 = 109 ns), and a discharged energy density of 1.47 J/cm³. These results demonstrate that the (1−x)Ba_0.96Ca_0.04TiO₃−xBi(Li_1/3Zr_2/3)O₃ ceramic system establishes a promising design paradigm for the creation and refinement of next-generation dielectrics for pulse power applications. Full article

With the electrification of generator sets, electric locomotives, new energy vehicles, and other industries, AC motors subject bearings to an electric field environment, leading to galvanic corrosion due to the use of variable frequency power supply drives. The phenomenon of bearing discharge breakdown in subway traction motors is a critical issue in understanding the relationship between shaft current strength and the extent of bearing damage. This paper analyzes the mechanism of impulse discharge that leads to galvanic corrosion damage in bearings at a microscopic level and conducts electric thermal coupling simulations of the traction motor bearing discharge breakdown process. It examines the temperature rise associated with lubricant film discharge breakdown during the dynamic operation of the bearing and investigates how breakdown channel parameters and operational conditions affect the temperature rise in the micro-region of bearing lubrication. Ultimately, the results of the electric thermal coupling simulation are validated through experimental tests. This study revealed that in an electric field environment, the load-bearing area of the outer ring experiences significantly more severe corrosion damage than the inner ring, whereas non-bearing areas remain unaffected by electrolytic corrosion. When the inner ring reaches a speed of 4500_rpm, the maximum widths of electrolytic corrosion pits for the outer and inner rings are measured at 89 um and 51 um, respectively. Additionally, the highest recorded temperatures for the breakdown channels in the outer and inner rings are 932 °C and 802 °C, respectively. Furthermore, as the inner ring speed increases, both the width of the electrolytic corrosion pits and the temperature of the breakdown channels rise. Specifically, at inner ring speeds of 2500_rpm, 3500_rpm, and 4500_rpm, the widths of the electrolytic pits in the outer ring raceway load zone were measured at 34 um, 56 um, and 89 um, respectively. The highest temperatures of the lubrication film breakdown channels were recorded as 612 °C, 788 °C, and 932 °C, respectively. This study provides a theoretical basis and data support for the protective and maintenance practices of traction motor bearings. Full article

This study presents the first investigation into the application of ultrasonic vibration-assisted electrical discharge machining (UV-EDM) using graphite electrodes for external cylindrical surface machining—an essential surface in the production of tablet punches and sheet metal-forming dies. A custom ultrasonic horn was designed and fabricated using 90CrSi material to operate effectively at a resonant frequency of 20 kHz, ensuring stable vibration transmission throughout the machining process. A Box–Behnken experimental design was employed to explore the effects of five process parameters—vibration amplitude (A), pulse-on time (Ton), pulse-off time (Toff), discharge current (Ip), and servo voltage (SV)—on two key performance indicators: material removal rate (MRR) and surface roughness (Ra). The optimization process was conducted in two stages: single-objective analysis to maximize MRR while ensuring Ra < 4 µm, followed by a hybrid multi-objective approach combining NSGA-II and the Analytic Hierarchy Process (AHP). The optimal solution achieved a high MRR of 9.28 g/h while maintaining Ra below the critical surface finish threshold, thus meeting the practical requirements for punch surface quality. The findings confirm the effectiveness of the proposed horn design and hybrid optimization strategy, offering a new direction for enhancing productivity and surface integrity in cylindrical EDM applications using graphite electrodes. Full article

To develop high-performance electrode materials for supercapacitors, in this paper, a heterostructured composite material of cerium sulfide and zinc sulfide quantum dots (CeS₂/ZnS QD) was successfully prepared by hydrothermal method. Characterization through scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) showed that ZnS QD nanoparticles were uniformly composited with CeS₂, effectively increasing the active sites surface area and shortening the ion diffusion path. Electrochemical tests show that the specific capacitance of this composite material reaches 2054 F/g at a current density of 1 A/g (specific capacity of about 256 mAh/g), significantly outperforming the specific capacitance of pure CeS₂ 787 F/g at 1 A/g (specific capacity 98 mAh/g). The asymmetric supercapacitor (ASC) assembled with CeS₂/ZnS QD and activated carbon (AC) retained 84% capacitance after 10,000 charge–discharge cycles. Benefited from the synergistic effect between CeS₂ and ZnS QDs, the significantly improved electrochemical performance of the composite material suggests a promising strategy for designing rare-earth and QD-based advanced energy storage materials. Full article

Background: Left bundle branch block (LBBB) following trans-catheter aortic valve implantation (TAVI) has been excluded from same-day discharge. Early identification of patients with stable LBBB can help facilitate same-day discharge. We aim to assess the role of 6-hour ECG to determine development of LBBB in patients undergoing TAVI. Methods: This is a prospective single-centre study of patients who have LBBB following elective TAVI procedures. All patients underwent ECGs pre-TAVI, as well as immediately, 6 h, and 24 h post-TAVI. Changes in ECG were compared at 6 and 24 h with the one immediately post TAVI. Results: The study included 115 patients with uncomplicated procedures. The mean age was 81 ± 7 years, with 54% male. A self-expanding valve was used in 67% of patients. Following TAVI, prolongations of PR interval and QRS duration were dynamic and reduced at 6 h. The change in PR interval at 6 and 24 h was comparable [−11 (−20 to 3) vs. −2 (−24 to 16) ms, p = 0.18]. Similarly, there was no statistical difference in the change of QRS duration at 6 and 24 h compared to the ECG immediately post-TAVI [−10 (−40 to −2) vs. −7 (−34 to 0) ms, p = 0.055]. Changes in ECG were also comparable in patients undergoing balloon-expandable and self-expanding valves. Conclusions: The current study supports that 6-hour ECG has the potential to reduce the need for prolonged continuous monitoring post-TAVI. ECG at 6 h can help optimise patient flow and facilitate early discharge. Future studies with larger sample sizes are required to confirm our findings. Full article

The significant advances in the surgical and medical treatment of gynecological cancer have led to improved survival outcomes of several subgroups of patients that were until recently opted out of treatment plans. Surgical cytoreduction has evolved through advanced surgical complexity procedures and the need for critical care of gynecological cancer patients has increased. Despite that, however, articles focusing on the need of perioperative monitoring of these patients completely lack from the international literature; hence, recommendations are still lacking. Critical care may be offered in different types of facilities with specific indications. These include the post-anesthesia care unit (PACU), the high dependency unit (HDU) and the intensive care unit (ICU) which have discrete roles and should be used judiciously in order to avoid unnecessary increases in the hospitalization costs. In the present review we focus on the pathophysiological alterations that are expected in gynecological cancer patients undergoing surgical treatment, provide current evidence and discuss indications of hospitalization as well as discharge criteria from intensive care facilities. Full article

Introduction: Falls are the leading cause of Emergency Department (ED) presentations among residents from residential aged care facilities (RACFs). While most current studies focus on post-fall evaluations and fall prevention, limited research has been conducted on decision-making in post-fall management. Objective: To develop and internally validate a model that can predict the likelihood of RACF residents being discharged from the ED after being presented for a fall. Methods: The study sample was obtained from a previous study conducted in Shepparton, Victoria, Australia. Consecutive samples were selected from January 2023 to November 2023. Participants aged 65 and over were included in this study. Results: A total of 261 fall presentations were initially identified. One patient with Australasian Triage Scale category 1 was excluded to avoid overfitting, leaving 260 presentations for analysis. Two logistic regression models were developed using prehospital and ED variables. The ED predictor model variables included duration of ED stay, injury severity, and the presence of an advance care directive (ACD). It demonstrated excellent discrimination (AUROC = 0.83; 95% CI: 0.79–0.89) compared to the prehospital model (AUROC = 0.77, 95% CI: 0.72–0.83). A simplified four-variable Discharge Eligibility after Fall in Elderly Residents (DEFER) score was derived from the prehospital model. The score achieved an AUROC of 0.76 (95% CI: 0.71–0.82). At a cut-off score of ≥5, the DEFER score exhibited a sensitivity of 79.7%, a specificity of 60.3%, a diagnostic odds ratio of 5.96, and a positive predictive value of 85.0%. Conclusions: The DEFER score is the first validated discharge prediction model for residents of RACFs who present to the ED after a fall. Importantly, the DEFER score advances personalised medicine in emergency care by integrating patient-specific factors, such as ACDs, to guide individualised discharge decisions for post-fall residents from RACFs. Full article

Water systems serve as multifaceted environmental pools for antibiotic-resistant bacteria (ARB) and resistance genes (ARGs), influencing human, animal, and ecosystem health. This review synthesizes current understanding of how antibiotics, ARB, and ARGs enter surface, ground, and drinking waters via wastewater discharge, agricultural runoff, hospital effluents, and urban stormwater. We highlight key mechanisms of biofilm formation, horizontal gene transfer, and co-selection by chemical stressors that facilitate persistence and spread. Case studies illustrate widespread detection of clinically meaningful ARB (e.g., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and mobile ARGs (e.g., sul1/2, tet, bla variants) in treated effluents, recycled water, and irrigation return flows. The interplay between treatment inefficiencies and environmental processes underscores the need for advanced treatment technologies, integrated monitoring, and policy interventions. Addressing these challenges is critical to curbing the environmental dissemination of resistance and protecting human and ecosystem health. Full article

During high-current vacuum arcing, asymmetric arcing with off-center plasma columns may occur due to stochastic discharge initiation and mechanical motion, receiving less research attention than symmetric arcing. The objective of this paper is to numerically analyze the influence law of asymmetric arc ignition on arc parameters. For 60 mm diameter contacts, three arc conditions of symmetric arcing, 33% arc offset, and 67% arc offset were modeled. The results show that the arc offset causes asymmetry in the arc’s distribution. For 33% offset, the pressure and number density on the side away from the root of the arc is about 50% of root values, while these parameters fall below 20% for the 67% offset. Simultaneously, arc offset elevates peak parameter values: under 33% offset, maxima for ion pressure, ion density, ion temperature, electron temperature, and current density rise 12%, 11%, 6%, 6%, and 14% versus symmetric arcing; during 67% offset, these escalate significantly to 67%, 61%, 12%, 18%, and 47%. This study contributes to providing reference for the analysis of vacuum interruption processes under asymmetric arcing conditions. Full article

Al/AgO seawater-activated batteries with high specific energy and high specific power are widely used at present. The AgO electrode determines the performance of the battery, with its active material utilization rate having a significant impact on the specific capacity, energy density and discharge capacity of the battery. Therefore, this study briefly introduces the structure and working principle of Al/AgO seawater-activated batteries. Starting from the AgO material itself, common preparation methods for such positive electrode materials—including sintered silver oxide electrodes, pressed silver oxide electrodes and thin-film silver oxide electrodes—are introduced, and the factors influencing their electrochemical performance are analyzed in depth. We elaborate on the relevant research progress regarding AgO electrodes in terms of improving battery performance, detailing the effects of the silver powder’s morphology, porosity, purity, ordered structure, surface treatment and doping modification methods on silver oxide electrodes. Finally, various methods for improving the electrochemical performance of silver oxide electrodes are detailed. Current challenges and possible future research directions are analyzed, and prospects for the future development of high-specific-energy batteries based on AgO electrode materials are discussed. Overall, this review highlights the characteristics of Al/AgO batteries, providing a theoretical basis for the development of high-performance Al/AgO batteries. Full article

The contamination of drinking water sources with selenium (Se) oxyanions, including selenite (Se(IV)) and selenate (Se(VI)), contains serious health hazards with an oral intake exceeding 400 µg/day and therefore requires urgent attention. Various natural and anthropogenic sources are responsible for high Se concentrations in aquatic environments. In addition, the chemical behavior and speciation of selenium can vary noticeably depending on the origin of the source water. The Se(VI) oxyanion is more soluble and therefore more abundant in surface water. Se levels in contaminated waters often exceed 50 µg/L and may reach several hundred µg/L, well above drinking water limits set by the World Health Organization (40 µg/L) and Germany (10 µg/L), as well as typical industrial discharge limits (5–10 µg/L). Overall, Se is difficult to remove using conventionally available physical, chemical, and biological treatment technologies. The recent literature has therefore highlighted promising advancements in Se removal using emerging technologies. These include advanced physical separation methods such as membrane-based treatment systems and engineered nanomaterials for selective Se decontamination. Additionally, other integrated approaches incorporating photocatalysis coupled adsorption processes, and bio-electrochemical systems have also demonstrated high efficiency in redox transformation and capturing of Se from contaminated water bodies. These innovative strategies may offer enhanced selectivity, removal, and recovery potential for Se-containing species. Here, a current review outlines the sources, distribution, and chemical behavior of Se in natural waters, along with its toxicity and associated health risks. It also provides a broad and multi-perspective assessment of conventional as well as emerging physical, chemical, and biological approaches for Se removal and/or recovery with further prospects for integrated and sustainable strategies. Full article

The large-scale utilization of hydrogen energy is currently hindered by challenges in low-cost production, storage, and transportation. This study focused on investigating the impact of the diaphragm cavity profile on the movement behavior and stress distribution of a dual-stage diaphragm compressor. Firstly, an experimental platform was established to test the gas mass flowrate and fluid pressures under various preset conditions. Secondly, a simulation path integrating the finite element method simulation, theoretical stress model, and movement model was developed and experimentally validated to analyze the diaphragm stress distribution and deformation characteristics. Finally, comparative optimization analyses were conducted on different types of diaphragm cavity profiles. The results indicated that the driving pressure differences at the top dead center position reached 85.58 kPa for the first-stage diaphragm and 75.49 kPa for the second-stage diaphragm. Under experimental conditions of 1.6 MPa suction pressure, 8 MPa second-stage discharge pressure, and 200 rpm rotational speed, the first-stage and second-stage diaphragms reached the maximum center deflections of 4.14 mm and 2.53 mm, respectively, at the bottom dead center position. Moreover, the cavity profile optimization analysis indicated that the double-arc profile (DAP) achieved better cavity volume and diaphragm stress characteristics. The first-stage diaphragm within the optimized DAP-type cavity exhibited 173.95 MPa maximum principal stress with a swept volume of 0.001129 m³, whereas the second-stage optimized configuration reached 172.57 MPa stress with a swept volume of 0.0003835 m³. This research offers valuable insights for enhancing the reliability and performance of diaphragm compressors. Full article

Background/Objectives: Hip fractures are highly prevalent worldwide, primarily affecting frail elderly patients. Frailty increases the risk of complications like postoperative delirium, which negatively impacts outcomes, including morbidity and mortality. Current recommendations favor a multidisciplinary approach and effective pain control, often using preoperative peripheral nerve blocks. We aimed to evaluate a multimodal approach’s efficacy in reducing postoperative delirium and complications in geriatric hip fracture patients. Methods: This study was conducted between March 2020 and June 2022. A total of 144 patients evaluated prior to the implementation of an optimized clinical pathway protocol (OCPP) were compared to 117 patients evaluated following its implementation. The protocol included early preoperative evaluation, streamlined medication adjustments, prompt surgical intervention and fascia iliaca compartment block (FICB) for analgesia. In addition, early patient mobilization and resumption of oral intake were promoted. The primary outcome was the incidence of delirium during hospitalization. Secondary outcomes were a composite of 30-day mortality or major complications, duration of stay, hospital readmission after discharge and 1-year mortality. Results: The OCPP intervention significantly reduced the incidence of postoperative delirium from 44% to 29% (a 33% relative reduction; p = 0.017), the rate of major complications or death was 14.5% in OCPP group and 25.7% in the control group (p = 0.02). Significantly more patients in the OCPP group were mobilized within 24 h (74.4% vs. 41.3% in the control group, p < 0.001). The median time to ambulation was also shorter in the OCPP group: 65 h (IQR: 39–115) compared to 72 h (IQR: 48–119.75) in the control group (p = 0.028). No differences were observed on hospital stay and 1-year mortality. Conclusions: Among patients undergoing hip fracture repair the implementation of a OCPP significantly reduced the incidence of postoperative delirium and the rate of major complications or death. This improvement was associated with significantly earlier patient mobilization and ambulation. The OCPP was not associated with a lower hospital stay and lower rate of one-year mortality. Full article

Supercapacitors are considered a bridge between batteries and capacitors due to their significant energy density, as well as power density. Herein, we prepared two novel electrodes of Fe_0.8Co_0.2S and Fe_0.8Co_0.2S/rGO composites and analyzed their supercapacitor performance. The results indicated that Fe_0.8Co_0.2S/rGO, prepared through co-precipitation and annealing, exhibited a higher specific capacitance value and improved electrochemical properties in comparison to Fe_0.8Co_0.2S due to the synergistic effect of rGO with Fe_0.8Co_0.2S. X-ray diffraction (XRD) confirmed the desired phases of Fe_0.8Co_0.2S, while scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) verified the microstructures and desired elements. Cyclic voltammetry (CV) confirmed an enhanced oxidation current from +25 mA to +49 mA at 10 mV/s, while galvanometric charge–discharge (GCD) showed an enhanced discharge time from 78 s to 300 s. As a result, the specific capacitance and energy density were enhanced from 74.3 F/g to 285.7 F/g and 2.84 Wh/kg to 10.9 Wh/kg, respectively. This contributed to a more than 283% increase in specific capacitance, as well as energy density. Overall, Fe_0.8Co_0.2S/rGO shows great potential for small-scale energy storage devices. Full article

Nokoué Lake is located in the south of Benin and is fed by the Ouémé and Sô Rivers. Its hydrosedimentary dynamics were modelled using Telemac2D, incorporating the main environmental factors of this complex ecosystem. The simulations accounted for flow rates and suspended solids concentrations during periods of high and low water. The main factors controlling sediment transport were identified. The model was validated using field measurements of water levels and suspended solids. The results show that the north–south current velocity ranges from 0.5 to 1 m/s during periods of high water and 0.1 to 0.5 m/s during low-water periods. Residual currents are influenced by rainfall, river discharge, and tides. Complex circulation patterns are caused by increased river flow during high water, while tides dominate during low water and transitional periods. The northern, western, and south-eastern parts of the lake have weak residual currents and are, therefore, deposition zones for fine sediments. The estimated average annual suspended solids load for 2022–2023 is 17 Mt. The model performance shows a strong agreement between the observed and simulated values: R² = 0.91 and NSE = 0.93 for water levels and R² = 0.86 and NSE = 0.78 for sediment transport. Full article