Search Results (56)

This article presents a modeling and analysis approach for a hybrid photovoltaic wind turbine (PV-WT) hydrogen production system. This study uses the TRNSYS simulation platform to evaluate the system under coastal climate conditions in Perth, Australia. The system encapsulates an advanced alkaline electrolyzer (ELE) and an alkaline fuel cell (AFC). A comprehensive 4E (energy, exergy, economic, and environmental) assessment is conducted. The analysis is based on hourly dynamic simulations over a full year. Key performance metrics include hydrogen production, energy and exergy efficiencies, carbon emission reduction, levelized cost of energy (LCOE), and levelized cost of hydrogen (LCOH). The TRNSYS model is validated against the existing literature data. The results show that the system performance is highly sensitive to ambient conditions. A sensitivity analysis reveals an energy efficiency of 7.3% and an exergy efficiency of 5.2%. The system has an entropy generation of 6.22 kW/K and a sustainability index of 1.055. The hybrid PV-WT system generates 1898.426 MWh of renewable electricity annually. This quantity corresponds to 252.7 metric tons of hydrogen production per year. The validated model shows a stable LCOE of 0.102 USD/kWh, an LCOH of 4.94 USD/kg, an energy payback time (EPBT) of 5.61 years, and cut CO₂ emissions of 55,777.13 tons. This research provides a thorough analysis for developing green hydrogen systems using hybrid renewables. This study also offers a robust prediction model, enabling further enhancements in hybrid renewable hydrogen production. Full article

Background: Patient motion poses significant challenges for the accurate delivery of radiotherapy. In children undergoing proton beam therapy (PBT), up to 30 treatments under general anesthesia may be required over a period of 6 to 8 weeks. To date, the impact of this many iterative anesthetic exposures on patient outcomes remains unclear. Objective: The primary objective of this study was to assess the impact of iterative anesthesia with propofol-based total intravenous anesthesia (propofol-TIVA) on overall survival. The secondary objective was to assess the association between propofol-TIVA and the occurrence of an unplanned admission or emergency room visit within 30 days of treatment start. Methods: This was a retrospective study of children (≤19 years) who had undergone PBT (with or without anesthesia) for central nervous system disease. The Log-rank test and Cox proportional hazards models were used for analysis. Propensity score matching and E-value analyses were used to adjust for selection bias. Results: The average age of the 461 children included was 9.0 years (SD ± 4.9). The majority, 261/461 (56.6%), were male, and 267/461 (57.9%) had undergone PBT without anesthesia. The group who underwent PBT with propofol-TIVA were younger (4.7 years vs. 12.2 years, p < 0.001) and had higher proportions of patients with treatment interruptions (111/194 [57.2%] vs. 118/267 [44.2%], p = 0.006), chemotherapy history (64/194 [33.0%] vs. 18/267 [6.7%], p < 0.001), concurrent chemotherapy (37/194 [19.1%] vs. 27/267 [10.1%], p = 0.006), and unplanned admissions/emergency room visits (26/194 [13.4%] vs. 1/267 [0.4%], p < 0.001). Overall survival rates (propofol-TIVA vs. no anesthesia) at 1yr (94% vs. 96%), 2 years (88% vs. 90%), and 3 years (88% vs. 89%) were similar between patient groups (p = 0.558). In the multivariable analysis, PBT with propofol-TIVA was associated with increased odds of an unplanned admission/emergency room visit before (OR, 38.311; 95%CI, 5.139–285.580; p < 0.001) and after (OR, 42.012; 95% CI, 5.322–331.632; p < 0.001; E-value = 83.52) propensity score matching. Conclusions: In this retrospective study of children undergoing PBT for central nervous system disease, there was no association between anesthesia exposure with propofol-based total intravenous anesthesia and overall survival. However, PBT with propofol-based total intravenous anesthesia was associated with an increased risk of an unplanned admission/emergency room visit within 30 days of treatment start. Full article

Background/Objectives: The necessity and clinical utility of routine pre-procedural blood tests (PBTs) before neuraxial blockade remain controversial. This study evaluates the effectiveness of PBTs in identifying clinically significant conditions in an outpatient setting. Methods: This single-center retrospective study involved patients who received neuraxial blockades from January 2020 to August 2023. We extracted medical information and laboratory data from the electronic medical records during the pre-procedural period. Through a multivariate regression analysis, we identified patient factors associated with abnormal laboratory results. Results: Advanced age (OR, 1.021; p = 0.026) and a history of cancer (OR, 2.359; p = 0.016) were significantly associated with elevated CRP levels (>0.30 mg/dL). Severe hyperglycemia (≥200 mg/dL) was found in 24 patients (3.88%), with a history of cancer being a strong predictor (OR, 6.764; p < 0.001). No significant abnormalities were observed in PT or PTT. Reduced eGFR (<60 mL/min/1.73 m²) was detected in 8.62% of patients, despite no prior history of renal dysfunction. A multivariate analysis revealed that advanced age, hypertension, cancer, and coronary artery disease were significant predictors of abnormal PBT results, highlighting the importance of selective testing in high-risk patients. Conclusions: Routine PBTs are not universally required for all patients undergoing neuraxial blockade but can provide crucial information in high-risk populations. A selective testing approach based on individual risk factors is recommended to optimize patient safety and resource utilization. Future studies should aim to establish clear guidelines for targeted PBT use. Full article

Defect annihilation of the IGZO/SiO₂ layer is of great importance to enhancing the bias stress stabilities of bottom-gate coplanar thin-film transistors (TFTs). The effects of annealing temperatures (T_a) on the structure of the IGZO/SiO₂ layer and the stabilities of coplanar IGZO TFTs were investigated in this work. An atomic depth profile showed that the IGZO/SiO₂ layer included an IGZO layer, an IGZO/SiO₂ interfacial mixing layer, and a SiO₂ layer. Higher T_a had only one effect on the IGZO layer and SiO₂ layer (i.e., strengthening chemical bonds), while it had complex effects on the interfacial mixing layer—including weakening M-O bonds (M: metallic elements in IGZO), strengthening damaged Si-O bonds, and increasing O-related defects (e.g., H₂O). At higher T_a, IGZO TFTs exhibited enhanced positive bias temperature stress (PBTS) stabilities but decreased negative bias temperature stress (NBTS) stabilities. The enhanced PBTS stabilities were correlated with decreased electron traps due to the stronger Si-O bonds near the interfacial layer. The decreased NBTS stabilities were related to increased electron de-trapping from donor-like defects (e.g., weak M-O bonds and H₂O) in the interfacial layer. Our results suggest that although higher T_a annihilated the structural damage at the interface from ion bombardment, it introduced undesirable defects. Therefore, to comprehensively improve electrical stabilities, controlling defect generation (e.g., by using a mild sputtering condition of source/drain electrodes and oxides) was more important than enhancing defect annihilation (e.g., through increasing T_a). Full article

To compare late renal effects in pediatric and adult patients with malignancies after PBT involving part of the kidney. A retrospective study was conducted to assess changes in renal volume and function in 24 patients, including 12 children (1–14 years old) and 12 adults (51–80 years old). Kidney volumes were measured from CT or MRI images during follow-up. Dose-volume histograms were calculated using a treatment planning system. In children, the median volume changes for the irradiated and control kidneys were −5.58 (−94.95 to +4.79) and +14.92 (−19.45 to +53.89) mL, respectively, with a relative volume change of −28.38 (−119.45 to −3.87) mL for the irradiated kidneys. For adults, these volume changes were −22.43 (−68.7 to −3.48) and −21.56 (−57.26 to −0.16) mL, respectively, with a relative volume change of −5.83 (−28.85 to +30.92) mL. Control kidneys in children exhibited a marked increase in size, while those in adults showed slight volumetric loss. The percentage of irradiated volume receiving 10 Gy (RBE) (V10) and 20 Gy (RBE) (V20) were significantly negatively associated with the relative volume change per year, especially in children. The CKD stage based on eGFR for all patients ranged from 1 to 3 and no cases with severe renal dysfunction were found before or after PBT. Late effects on the kidneys after PBT vary among age groups. Children are more susceptible than adults to significant renal atrophy after PBT. V10 and V20 might serve as predictors of the degree of renal atrophy after PBT, especially in children. PBT has a minimal impact on deterioration of renal function in both children and adults. Full article

The Tietonggou pluton is mainly composed of gabbroic diorite and diorite. The petrology, zircon U-Pb age, and geochemistry of the Tietonggou diorite have been studied to determine its petrogenesis and metallogenic significance. The diorite samples have 56–58 wt% SiO₂ and 11–14 wt% Al₂O₃ and are peraluminous and sodic (Na₂O/K₂O = 1.29–2.07). All the samples are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs; e.g., Rb, Ba, and Sr) but depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs; e.g., Zr, Nb, and Ta), suggesting subduction-related affinities. The rocks have narrow ranges of (²⁰⁶Pb/²⁰⁴Pb)_t (18.5–19.0), (²⁰⁷Pb/²⁰⁴Pb)_t (15.71–15.75), and (²⁰⁸Pb/²⁰⁴Pb)_t (38.4–39.0) ratios, respectively. Zircons from the Tietonggou diorite yielded a weighted average U-Pb age of 132.86 ± 0.92 Ma (MSWD = 0.48), whilst those from the nearby Laowa diorite yielded 129.72 ± 0.61 Ma (MSWD = 1.05). This suggests that the rocks represent Early Cretaceous plutons, coeval with the peak lithospheric thinning in eastern North China Craton (NCC). The magma likely originated from partial melting of the enriched lithospheric mantle and was contaminated by ancient lower NCC crustal materials. Our study clarifies the tectonic background of the Tietonggou pluton and provides support for the study of the genesis of Fe–skarn deposits in western Shandong. Full article

This paper investigates making an injection mouldable conductive plastic formulation that aims for conductivity into the electromagnetic interference (EMI) shielding range, with good mechanical properties (i.e., stiffness, strength, and impact resistance). While conductivity in the range (electrostatic charge dissipation) and EMI shielding have been attained by incorporating conductive fillers such as carbon black, metals powders, and new materials, such as carbon nanotubes (CNTs), this often occurs with a drop in tensile strength, elongation-to-break resistance, and impact resistance. It is most often the case that the incorporation of high modulus fillers leads to an increase in modulus but a drop in strength and impact resistance. In this work, we have used short carbon fibres as the conductive filler and selected a 50/50 PBT/rPET (recycled PET) for the plastic matrix. Carbon fibres are cheaper than CNTs and graphenes. The PBT/rPET has low melt viscosity and crystallises sufficiently fast during injection moulding. To improve impact resistance, a styrene-ethylene-butadiene-styrene (SEBS) rubber toughening agent was added to the plastic. The PBT/rPET had very low-impact resistance and the SEBS provided rubber toughening to it; however, the rubber caused a drop in the tensile modulus and strength. The short carbon fibre restored the modulus and strength, which reached higher value than the PBT/rPET while providing the conductivity. Scanning electron microscope pictures showed quite good bonding of the current filler (CF) to the PBT/rPET. An injection mouldable conductive plastic with high conductivity and raised modulus, strength, and impact resistance could be made. Full article

Novel brominated flame retardants (NBFRs) and dechlorane plus (DP) have been widely used as alternatives to traditional BFRs. However, little is known about the temporal trends of NBFR and DP pollution in e-waste recycling sites. In the current study, three composite sediment cores were collected from an e-waste-polluted pond located in a typical e-waste recycling site in South China to investigate the historical occurrence and composition of NBFRs and DP. The NBFRs and DP were detected in all layers of the sediment cores with concentration ranges of 5.71~180,895 and 4.95~109,847 ng/g dw, respectively. Except for 2,3,5,6-tetrabromo-p-xylene (pTBX) and 2,3,4,5,6-pentabromoethylbenzene (PBEB), all the NBFR compounds and DP showed a clear increasing trend from the bottom to top layers. These results implied the long-term and severe contamination of NBFRs and DP. Decabromodiphenyl ethane (DBDPE) was the most abundant NBFR with the contribution proportions of 58 ± 15%, 73 ± 15%, and 71 ± 18% in three sediment cores, followed by 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) and pentabromobenzene (HBB). The ratios of BTBPE/Octa-BDEs and DBDPE/Deca-BDEs varied from 0.12 to 60 and from 0.03 to 0.49, respectively, which had no clear increase trends with a decrease in sediment depth. As for DP, the f_anti values (the concentration ratios of anti-DP to the sum of anti-DP and syn-DP) in sediment cores ranged from 0.41 to 0.83, almost falling in the range of those in DP technical products, suggesting that DP degradation did not occur in sediment cores. The environmental burdens of DBDPE, BTBPE, HBB, PBT, PBEB, pTBX, and DP were estimated to be 34.0, 5.67, 10.1, 0.02, 0.02, 0.01, and 34.8 kg, respectively. This work provides the first insight into the historical contamination status of NBFRs and DP in the sediments of an e-waste recycling site. Full article

Background: Acetazolamide is a non-competitive inhibitor of carbonic anhydrase, an enzyme expressed in different cells of the central nervous system (CNS) and involved in the regulation of cerebral blood flow (CBF). The aim of this review was to understand the effects of acetazolamide on CBF, intracranial pressure (ICP) and brain tissue oxygenation (PbtO₂) after an acute brain injury (ABI). Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA), we performed a comprehensive, computer-based, literature research on the PubMed platform to identify studies that have reported the effects on CBF, ICP, or PbtO₂ of acetazolamide administered either for therapeutic or diagnostic purposes in patients with subarachnoid hemorrhage, intracerebral hemorrhage, traumatic brain injury, and hypoxic-ischemic encephalopathy. Results: From the initial search, 3430 records were identified and, through data selection, 11 of them were included for the qualitative analysis. No data on the effect of acetazolamide on ICP or PbtO₂ were found. Cerebral vasomotor reactivity (VMR—i.e., the changing in vascular tone due to a vasoactive substance) to acetazolamide tends to change during the evolution of ABI, with the nadir occurring during the subacute stage. Moreover, VMR reduction was correlated with clinical outcome. Conclusions: This systematic review showed that the available studies on the effects of acetazolamide on brain hemodynamics in patients with ABI are scarce. Further research is required to better understand the potential role of this drug in ABI patients. Full article

The growing demand for energy has led to the popularity of building integrated photovoltaic (BIPV) systems. However, photovoltaic (PV) system efficiency decreases as the temperature increases. To address this issue, a study was conducted on a BIPV thermal (BIPVT) system, which can generate both thermal and electrical energy, to enhance its efficiency. In this study, for the cold weather in Tabriz city in Iran, BIPV and BIPVT systems are compared with each other in terms of energy, economy, exergy, and environment (4E) and the goal is to fully supply the thermal and electrical load of the desired building. The studied criteria are electrical power and heat recovery, payback time (PBT), exergy efficiency, and saved carbon dioxide (SCD) from the energy, economic, exergy, and environmental point of view, respectively. Finally, it is concluded that in cold weather, the BIPVT system can achieve a 7.15% improvement in produced power compared to the BIPV system and 52.2% of the building’s heating needs are provided. It also causes the exergy efficiency to improve by an average of 1.69% and saves 34.98 ton of carbon dioxide. The PBT of this study is calculated as 5.77 years for the BIPV system and 4.78 years for the BIPVT system. Full article

This study employs a life cycle assessment (LCA) approach to investigate the environmental burden of photovoltaic power generation systems that use multi-crystalline silicon (multi-Si) modules in Pakistan. This study evaluates the energy payback time (EPBT) of this class of systems, and considers various environmental impacts, including climate change, acidification, and eutrophication. The assessment accounts for upstream, midstream, and downstream processes, including cell as well as module production. The critical stages in the production cycle were identified, including the metallic silicon transformation into solar silicon and the assembly of the panels, which involve energy-intensive materials such as aluminum frames and glass roofing. Despite using the most efficient conversion technology, the former stage consumes a significant amount of electricity. This study reveals that multi-Si PV systems in Pakistan have an EPBT that is considerably less than their lifespan, ranging from 2.5 to 3.5 years. These findings suggest that the development of PV systems in Pakistan is a very interesting option for energy production. Additionally, this study compares solar PV and wind power generation systems in various regions of Pakistan. The study outcomes can facilitate evidence-based decision-making processes in the renewable energy sector and contribute significantly to Pakistan’s endeavor to transition toward a sustainable energy system. Full article

In this study, we developed highly efficient nonwoven membranes by modifying the surface of polypropylene (PP) and poly(butylene terephthalate) (PBT) through photo-grafting polymerization. The nonwoven membrane surfaces of PP and PBT were grafted with poly(ethylene glycol) diacrylate (PEGDA) in the presence of benzophenone (BP) and metal salt. We immobilized tertiary amine groups as BP synergists on commercial nonwoven membranes to improve PP and PBT surfaces. In situ Ag, Au, and Au/Ag nanoparticle formation enhances the nonwoven membrane surface. SEM, FTIR, and EDX were used to analyze the surface. We evaluated modified nonwoven membranes for photocatalytic activity by degrading methylene blue (MB) under LED and sunlight. Additionally, we also tested modified membranes for antibacterial activity against E. coli. The results indicated that the modified membranes exhibited superior efficiency in removing MB from water. The PBT showed the highest efficiency in dye removal, and bimetallic nanoparticles were more effective than monometallic. Modified membranes exposed to sunlight had higher efficiency than those exposed to LED light, with the PBT/Au/Ag membrane showing the highest dye removal at 97% within 90 min. The modified membranes showed reuse potential, with dye removal efficiency decreasing from 97% in the first cycle to 85% in the fifth cycle. Full article

Amongst chairside CAD/CAM materials, the use of lithium-based silicate glass–ceramics (LSGC) for indirect restorations has recently been increasing. Flexural strength is one of the most important parameters to consider in the clinical selection of materials. The aim of this paper is to review the flexural strength of LSGC and the methods used to measure it. Methods: The electronic search was completed within PubMed database from 2 June 2011 to 2 June 2022. English-language papers investigating the flexural strength of IPS e.max CAD, Celtra Duo, Suprinity PC, and n!ce CAD/CAM blocks were included in the search strategy. Results: From 211 potential articles, a total of 26 were identified for a comprehensive analysis. Categorization per material was carried out as follows: IPS e.max CAD (n = 27), Suprinity PC (n = 8), Celtra Duo (n = 6), and n!ce (n = 1). The three-point bending test (3-PBT) was used in 18 articles, followed by biaxial flexural test (BFT) in 10 articles, with one of these using the four-point bending test (4-PBT) as well. The most common specimen dimension was 14 × 4 × 1.2 mm (plates) for the 3-PBT and 12 × 1.2 mm (discs) for BFT. The flexural strength values for LSGC materials varied widely between the studies. Significance: As new LSGC materials are launched on the market, clinicians need to be aware of their flexural strength differences, which could influence the clinical performance of restorations. Full article

Forests are essential for the provision of water, financial resources, food, and carbon, and offer immense ecosystem service values. The accurate, quantitative, and objective evaluation of forest ecosystem service (FES) values can help uncover methods for realizing ecological product value, which in turn supports forest conservation and ecological benefit enhancement. In China, FES valuation methods are diverse and tailored to specific objectives, encompassing matter quantity assessment, value quantity assessment, energy value analysis, and landscape ecological modeling methods. The “Forest Ecosystem Service Function Assessment Specification” guideline plays a crucial role in fostering standardized valuation. Carbon-related ecosystem services have been increasingly studied in China; however, valuation challenges remain, including data accuracy, the double counting of ecosystem services, methodological limitations, and the incomplete assessment of non-use values. Regarding value realization, the development of payment for ecosystem services (PES), ecological product benefit trading (EPBT), ecological premiums, and ecological industries has seen gradual progresses in recent years. However, realization approaches still depend on government support, and the establishment of market-oriented strategies requires further reinforcement. Enhancing FES valuation necessitates the integration of interdisciplinary and multi-method approaches, as well as the creation of an accounting and assessment mechanism. Realization approaches must not only be continuously expanded but also consistently innovated over time. It is essential to consider the impact of market development on FES valuation; establish robust realization approaches; reinforce promotional and guarantee mechanisms; and increase the efficacy of policy management. Full article

This paper presents a life cycle assessment (LCA) analysis of a new, high-concentration photovoltaic (HCPV) technology developed as part of the HIPERION project of hybrid photovoltaics for efficiency record using an integrated optical technology. In the LCA calculations, the production stage of a full module was adopted as a functional unit. SimaPro version 9.00.49, the recent Ecoinvent database (3.8), and the IPCC 2021 GWP 100a environmental model were applied to perform the calculations. The environmental impact of the HCPV panel was determined for constructional data and for recycling of the main elements of the module. The results of the calculations show that recycling of PMMA, rubber, and electronic elements reduced the total carbon footprint by 17%, from 240 to 201 kg CO₂-eq. The biggest environmental load was generated by the PV cells: 99.9 kg CO₂eq., which corresponds to 49.8% (41.7% without recycling) of the total environmental load due to the large number of solar cells used in the construction. The emission of CO₂ over a 25-year lifespan was determined from 17.1 to 23.4 g CO₂-eq/kWh (20.4 to 27.9 without recycling), depending on the location. The energy payback time (EPBT) for the analyzed module is 0.87 and 1.19 years, depending on the location and the related insolation factors (Madrid: 470 kWh/m², Lyon: 344 kWh/m²). The results of the calculations proved that the application of recycling and recovery methods for solar cells can improve the sustainability of the photovoltaic industry. Full article