Search Results (684)

This study presents the design and validation of an automated skip loading system for vertical shaft hoisting operations, aimed at addressing inefficiencies in current manual systems that contribute to consistent underperformance in meeting daily production targets. Initial assessments revealed a task completion rate of 91.6%, largely due to delays and inaccuracies in manual ore loading and accounting. To resolve these challenges, an automated system was developed using a bin and conveyor mechanism integrated with a suite of industrial automation components, including a programmable logic controller (PLC), stepper motors, hydraulic cylinders, ultrasonic sensors, and limit switches. The system is designed to transport ore from the draw point, halt when one ton is detected, and activate the hoisting process automatically. Digital simulations demonstrated that the automated system reduced loading time by 12% and increased utilization by 16.6%, particularly by taking advantage of the 2 h post-blast idle period. Financial evaluation of the system revealed a positive Net Present Value (NPV) of $1,019,701, a return on investment (ROI) of 69.7% over four years, and a payback period of 2 years and 11 months. The study concludes that the proposed solution significantly improves operational efficiency and recommends further enhancements to the hoisting infrastructure to fully optimize performance. Full article

Global warming, driven by greenhouse gas (GHG) emissions, is accelerating globally and highlights the need for effective mitigation strategies. This study assesses the economic feasibility of rainbow trout aquaculture by incorporating GHG emissions into its analysis, thereby contributing to mitigation efforts in the fisheries sector. Focusing on two farming systems—recirculating aquaculture systems (RAS) and flow-through systems (FTS)—we estimated GHG emissions and conducted an economic evaluation using data collected through field surveys. The average GHG emission was 7.14 kg CO₂ eq per kilogram of trout produced, with RAS showing lower emissions than FTS. Electricity and feed were identified as the primary emission sources. The economic analysis revealed an average net present value (NPV) of USD 987,609 and an internal rate of return (IRR) of 18%, with RAS outperforming FTS in profitability. A sensitivity analysis under carbon pricing showed that economic feasibility was maintained, but the NPV declined by about 24% under the carbon tax scenario. Overall, these findings underscore the importance of balancing profitability and emission reduction for sustainable aquaculture management. Full article

In arid countries like Oman, fan–pad cooling systems are commonly used in greenhouse cultivation. However, in such harsh environmental conditions, a fan–pad cooling system can be inefficient, result in high water and energy consumption, and may cause plant and soil pathogens issues. To address these challenges, this study evaluated the technical performance of a greenhouse designed with the new concept of an on-grid, solar-powered, and fan-chiller tube bank (FCTB) cooling system, focusing on water use efficiency (WUE) and energy use efficiency (EUE) following pot-grown okra. In addition, greenhouse gas (GHG) emissions and financial aspects were evaluated through cost–benefit and cash flow analyses. This research was conducted with a Quonset side-walled single-span greenhouse equipped with a solar-powered FCTB cooling system and automatic scheduled irrigation system. Water and electricity consumption was recorded, and surplus energy supplied to the electricity grid was estimated. The greenhouse efficiencies were evaluated by computing the EUE, total WUE, cooling water use efficiency (CWUE), and irrigation water use efficiency (IWUE). The solar-powered FCTB greenhouse enhanced EUE, achieving a value of 1.16 and a positive net energy of 163.87 MJ·m⁻². The WUE, CWUE, and IWUE were 0.91 kg·m⁻³, 1.63 kg·m⁻³, and 2.07 kg·m⁻³, respectively. The economic assessment showed that okra cultivation with a solar-powered FCTB cooling system was economically unfeasible, as indicated by a benefit–cost ratio of 0.88. However, cucumber (IRR 46%, NPV 2.13 × 10⁴ USD) and cherry tomatoes (IRR 38%, NPV 1.98 × 10⁴ USD) demonstrated economic feasibility as supported by positive net present value (NPV) and the internal rate of return (IRR) values. Furthermore, incorporating solar energy with the FCTB cooling system enhanced the greenhouse’s sustainability, efficiencies, and profitability. This study recommends further research with this system for Oman’s seasonal effect with high-value crops and optimizing the size of the solar panel system to see how the energy and other efficiency components will vary. Full article

Against the backdrop of the global transition towards clean energy, deep-sea wind-power hydrogen production integrates offshore wind with green hydrogen technology. Addressing the technical coupling complexity and the impact of uncertain hydrogen prices, this paper develops a capacity optimization model. The model incorporates floating wind turbine output, the technical distinctions between alkaline (ALK) electrolyzers and proton exchange membrane (PEM) electrolyzers, and the synergy with energy storage. Under three hydrogen price scenarios, the results demonstrate that as the price increases from 26 CNY/kg to 30 CNY/kg, the optimal ALK capacity decreases from 2.92 MW to 0.29 MW, while the PEM capacity increases from 3.51 MW to 5.51 MW. Correspondingly, the system’s Net Present Value (NPV) exhibits an upward trend. To address the limitations of traditional methods in handling multi-dimensional benefit correlations and information ambiguity, a comprehensive benefit evaluation framework encompassing economic, technical, environmental, and social synergies was constructed. Sensitivity analysis indicates that the comprehensive benefit level falls within a relatively high-efficiency interval. The numerical characteristics, an entropy value of 3.29 and a hyper-entropy of 0.85, demonstrate compact result distribution and robust stability, validating the applicability and stability of the proposed offshore wind–hydrogen benefit assessment model. Full article

Progressive climate change and the increasing concentration of carbon dioxide in the atmosphere represent one of the most serious challenges facing modern energy systems. At the same time, the global overproduction of plastics, particularly polyethylene terephthalate (PET), places a significant burden on the natural environment and waste management infrastructure. Electrochemical reactors offer a promising solution by enabling the simultaneous conversion of CO₂ and EG into valuable products such as carbon monoxide and glycolic acid, using electricity derived from renewable energy sources. Carbon monoxide can be further processed into high-energy synthetic fuels, such as propanol, while glycolic acid holds substantial importance in the pharmaceutical and plastics industries. An economic analysis was conducted to estimate the capital expenditures required for an electrochemical reactor and to assess the investment’s profitability based on the net present value (NPV) indicator. In addition, a Life Cycle Assessment (LCA) was carried out to evaluate the environmental impact of the proposed technology, with particular attention to its carbon footprint. The results indicate that the profitability of the system strongly depends on the market price and purity of glycolic acid, as well as on access to low-cost renewable electricity. The LCA confirms a significantly lower carbon footprint compared to conventional CO production, though further technological advancements are required for industrial deployment. Full article

Accurate sex estimation is critical in forensic anthropology for developing biological profiles, with the mandible serving as a valuable alternative when crania or pelvic bones are unavailable. This study aims to enhance mandibular sex estimation using deep learning on 3D models in a southern Croatian population. A dataset of 254 MSCT-derived 3D mandibular models (127 male, 127 female) was processed to generate 4096-point clouds, analyzed using an adapted PointNet++ architecture. The dataset was split into training (60%), validation (20%), and test (20%) sets. Unsupervised analysis employed an autoencoder with t-SNE visualization, while supervised classification used logistic regression on extracted features, evaluated by accuracy, sensitivity, specificity, PPV, NPV, and MCC. The model achieved 93% cross-validation accuracy and 92% test set accuracy, with saliency maps highlighting key sexually dimorphic regions like the chin, gonial, and condylar areas. A user-friendly Gradio web application was developed for real-time sex classification from STL files, enhancing forensic applicability. This approach outperformed traditional mandibular sex estimation methods and could have potential as a robust, automated tool for forensic practice, broader population studies and integration with diverse 3D data sources. Full article

The increasing generation of agricultural waste poses both environmental and economic challenges, particularly in rural areas with limited infrastructure. Anaerobic digestion has emerged as a sustainable alternative, enabling the valorization of waste and the production of biogas and biofertilizer. This study evaluated the economic and environmental gains of mono- and co-digestion of equine manure and vegetable waste using biodigesters of different capacities across four simulated projects—Project 1 (15 m² biodigester with monodigestion), Project 2 (15 m² biodigester with co-digestion), Project 3 (20 m² biodigester with monodigestion), and Project 4 (20 m² biodigester with co-digestion). Economic feasibility was assessed through indicators such as Net Present Value (NPV), Internal Rate of Return (IRR), Modified IRR (MIRR), Profitability Index (PI), Benefit-Cost Ratio (B/C), Discounted Payback Period, sensitivity analysis, and Monte Carlo simulation, adopting a Minimum Attractiveness Rate (MAR) of 6.43% per year. Environmental benefits were estimated based on the annual reduction of CO₂ equivalent emissions. The results showed that all projects were economically viable and had the potential to mitigate up to 36 tons of CO₂eq per year. Additionally, an eco-efficiency indicator (NPV per CO₂eq avoided) was calculated to enable an integrated assessment of economic performance and environmental impact. Projects using 20 m³ biodigesters achieved the best results, with Project 3 being the most eco-efficient (USD256.05/tCO₂eq), while Project 4 yielded the highest absolute return in all economic analysis tools: NPV (USD 9063.81), IRR (25.10%), MIRR (10.95%), PI (USD 1.65), B/C (USD 1.65) and DPP (4.56 years). The integrated analysis underscores the significance of co-digestion and economies of scale in encouraging the adoption of this technology by small rural producers. Full article

Background/Objectives: Atrial fibrillation (AF) often occurs in episodes that are sudden and go unnoticed, reducing the chances of anticoagulation. We evaluated a two-stage AI ECG screening protocol that uses a single ECG model at initial screening and, if necessary, a serial ECG model after short interval follow-up to enhance accuracy while saving monitoring resources. Methods: We analyzed 248,612 12-lead ECGs from 164,793 adults (AF, n = 10,735) for model development and assessed the protocol in 11,349 eligible patients with longitudinal ECGs. The proposed algorithm first applied a single-ECG AI model at the initial visit, followed by a serial-ECG AI model three months later if AF was not initially detected. The model’s performance was evaluated using several metrics, including the area under the receiver operating characteristic curve (AUROC), sensitivity, specificity, accuracy, and F1 score. Results: The protocol achieved an AUROC of 0.908 with a sensitivity of 88.1%, specificity of 78.7%, positive predictive value (PPV) of 30.2%, negative predictive value (NPV) of 98.4%, accuracy of 79.6%, and an F1 score of 0.450. Among patients with a history of stroke (n = 551), 84.9% were correctly identified as AF-positive under the protocol. Conclusions: A sequential AI ECG strategy maintains high NPV at entry and improves PPV with longitudinal confirmation. This approach can prioritize ambulatory monitoring for those most likely to benefit and merits prospective, multi-center validation and cost-effectiveness assessment. Full article

Given the demand for sustainable and cost-effective manure management in livestock systems, this study evaluated the economic feasibility of cattle manure treatment via composting and anaerobic digestion (AD) under different configurations. Five scenarios were compared: composting without solid–liquid separation, AD without separation at 20- and 30-day hydraulic retention times (HRTs), and combined systems with separation, composting the solid fraction and digesting the liquid. The analysis was based on a 200-cow herd and experimental data, with 15-year projected cash flows. Economic indicators included net present value (NPV), internal rate of return (IRR), discounted payback period (DPP), benefit–cost ratio (B/C), modified internal rate of return (MIRR), uniform annual equivalent (UAE), and profitability index (PI), supported by sensitivity analysis and Monte Carlo simulation. All scenarios were viable and posed low risk. Energy and fertilizer value were key drivers. The scenario 30-day HRT without separation had the best financial performance (NPV = 53,407.15 USD; IRR = 15.54%; DPP = 7.33 years; B/C = 1.57; MIRR = 9.28%; UAE = 5654.48 USD; PI = 1.66) and is recommended for capitalized farms seeking higher returns. Composting had lower returns (NPV = 9832.06 USD) but required the lowest investment, remaining a cost-effective alternative for smallholders. Full article

This study evaluates the economic feasibility of offshore wind farm development on idle coastal areas in Korea, focusing on the Wando Geumil Offshore Wind Farm (GOWF) as a representative case. Offshore wind farms are increasingly recognized as key contributors to achieving carbon neutrality, and Korea’s coastal idle zones offer strategic potential for large-scale deployment with minimal land-use conflict. To address market uncertainty—particularly the sensitivity of revenues to the Renewable Portfolio Standard (RPS) and Renewable Energy Certificate (REC) weight—this research applies both the Discounted Cash Flow (DCF) method and Real Options Analysis (ROA), incorporating expansion and contraction scenarios. Using eleven years of historical System Marginal Price (SMP) and REC data, we estimate price volatility via a Geometric Brownian Motion (GBM) model (σ = 23.04%). The DCF results indicate a negative Net Present Value (NPV) of −313.7 million USD, suggesting baseline infeasibility. In contrast, ROA adds strategic value, with the expansion option yielding 69.6 million USD and the contraction option 2.1 million USD in additional project value. These findings demonstrate that integrating policy-driven revenue uncertainty into ROA substantially alters investment recommendations, offering practical guidance for optimizing offshore wind farm deployment on Korea’s idle coastal sites. Full article

Congenital cytomegalovirus (CMV) is a major cause of neonatal morbidity, particularly sensorineural hearing loss, yet its early detection remains challenging. While urinary PCR is the current diagnostic gold standard, its implementation in neonatal settings is often limited by feasibility issues. Salivary PCR presents a more practical alternative, but its diagnostic accuracy has remained uncertain. This systematic review and meta-analysis aimed to evaluate the performance of salivary PCR compared to urinary PCR in detecting congenital CMV in neonates. Following PRISMA guidelines, 15 observational studies involving 29,617 neonates were analyzed using a random-effects model. Pooled sensitivity and specificity were 0.99 and 1.00, respectively, with a negative predictive value (NPV) of 1.00 and a positive predictive value (PPV) of 0.91, despite moderate heterogeneity. Subgroup analysis showed high diagnostic performance across general neonates, infants of seropositive mothers and high-risk neonates (referring to neonates that are small for their gestational age (SGA), neonates who failed hearing screening, and neonates with CMV-related congenital abnormalities). The general group had the highest specificity (0.999), while high-risk neonates showed the highest sensitivity (0.981). Across all groups, NPV remained consistently above 0.994, with PPV ranging from 0.848 to 0.981. These findings confirm that salivary PCR is a highly accurate and feasible tool for congenital CMV diagnosis. Full article

Background/Objectives: Our study evaluates the performance of the CDO1 and CELF4 methylation assay of cervical scrapings in diagnosing endometrial cancer. Methods: Patients referred for abnormal uterine bleeding, suspected endometrial pathology on imaging, endometrial hyperplasia, or cancer, who were indicated for endometrial sampling +/− hysteroscopy +/− hysterectomy, were recruited prospectively from the gynecology clinic of Prince of Wales Hospital, Hong Kong, from January 2023 to November 2024. Methylation assay was performed on the cervical scrapings of the participants, with the results compared to endometrium histology obtained on the same day. Results: Methylation assay results of 675 patients were compared to 629 outpatient endometrial assessments and 46 hysterectomy histology. The assay yields an accuracy of 97.3%, sensitivity of 84.1%, specificity of 98.8%, PPV of 89.2%, and NPV of 98.2%. The AUC is 0.92 with a Kappa coefficient of 0.85. The false-negative rate was 0.8% among the 629 endometrial assessment cases. Endometrial thickness, abnormal cervical cytology, and endometrial hyperplasia significantly affected the accuracy. Among seven false-positive cases, five had endometrial hyperplasia and two had cervical intraepithelial neoplasia. Eventually, three patients were diagnosed with endometrial cancer and one with cervical cancer 1 to 4 months later. Conclusions: Methylation assay of cervical scrapings is highly accurate in diagnosing endometrial cancer with a high sensitivity, specificity, and low false-negative rate. It can act as a triage to reduce invasive endometrial assessment. All false-positive cases were related to neoplastic processes in the genital tract, indicating that it may be useful for detecting cancer early, before histological change is evident. Full article

Background/Objectives: This study aimed to: (1) evaluate the effectiveness of the Croatian version of the Hearing Handicap Inventory for the Elderly—Screening Version (HHIE-S-CRO) in screening for hearing loss greater than 20 dB HL in the better-hearing ear among adults aged ≥ 60 years; (2) assess its utility in identifying individuals with hearing loss ≥ 40 dB HL in the better-hearing ear, meeting current Croatian eligibility criteria for state-funded hearing aid rehabilitation; and (3) determine whether the emotional and social components of perceived hearing handicap can be meaningfully distinguished. Methods: Validity of the HHIE-S-CRO was analyzed using Spearman’s correlation coefficient, the Mann–Whitney test and the factor analysis, while reliability was assessed via Cronbach’s alpha and the intraclass correlation coefficient (ICC). Receiver operating characteristic (ROC) curve analysis was calculated to determine sensitivity, specificity, and positive and negative predictive values (PPV and NPV) at various cut-off scores of the HHIE-S-CRO total for specified audiometric criteria (better ear pure-tone average > 20 dB HL and ≥40 dB HL). The nonparametric Wilcoxon Matched Pairs Test was used to compare scores on the emotional and social subscales of the HHIE-S-CRO. Results: The HHIE-S-CRO demonstrated excellent internal consistency (Cronbach’s alpha = 0.92) and high repeatability of the results (ICC = 0.92). Discriminant, convergent, construct and predictive validity were confirmed. The area under the curve (AUC) for detecting hearing loss > 20 dB HL in the better ear was 0.95, with a sensitivity of 90.67% and specificity of 94.65% at a cut-off score of 6. For the Croatian threshold for state-supported hearing aid rehabilitation (≥40 dB HL in the better-hearing ear), similarly favorable screening characteristics were found at a cut-off score of 10. Conclusions: Based on these findings, the HHIE-S-CRO appears to offer sufficient sensitivity and specificity to support two key clinical applications: (1) screening for hearing loss > 20 dB HL in individuals aged 60 and older, and (2) identifying individuals within this age group who may be eligible for state-supported hearing aid-based rehabilitation. Full article

Background/Objectives: The preoperative detection of sentinel lymph nodes (SLN) using technetium-99m (Tc-99m) is crucial for surgical staging in early-stage endometrial cancer (EC). The optimal imaging timing and modality remain debated. This study compares early planar scintigraphy (30 min), SPECT/CT (1 h), and 18-h planar scintigraphy after a single Tc-99m injection. Methods: A total of 125 patients with early-stage EC underwent SLN mapping with Tc-99m (120 MBq). Imaging included 30-min planar scintigraphy, SPECT/CT (1 h), and 18-h planar scintigraphy on the day of surgery. Detection sensitivity, the bilateral mapping rate, and image quality (signal-to-noise ratio (SNR), contrast factor (C-factor)) were evaluated, with intraoperative gamma probe detection and histopathology as references. Results: The 18-h planar scintigraphy achieved the highest SLN detection sensitivity (94.4%, 118/125), compared with SPECT/CT (87.2%, OR = 2.48, 95% CI: 0.98–6.27, p = 0.051) and 30-min scintigraphy (72.0%). Only the 18-h protocol underwent intraoperative and histopathological verification; results for 30-min planar and 1-h SPECT/CT were based on imaging alone, which limits direct comparability. Bilateral detection was higher at 18 h (80.80%) than SPECT/CT (73.60%). All SLNs detected at 18 h were confirmed intraoperatively and histologically, yielding 100% PPV (95% CI: 96.9–100.0%) and NPV (95% CI: 59.0–100.0%). The 18-h protocol showed superior imaging contrast (C-factor: 10.30 ± 1.22) despite lower residual activity. The method remained effective in patients with BMI ≥ 30 (94.00%). Only 1.60% of patients required hysterectomy before mapping due to background interference. Conclusions: The 18-h planar scintigraphy is a highly effective, low-cost, and accessible method for SLN detection in early-stage EC, potentially reducing the need for SPECT/CT, radiation exposure, and costs. Full article

Background and Objectives: The assessment of cervical lordosis is essential for surgical planning and outcome prediction in patients with cervical spine pathology. This study aims to evaluate the accuracy of cervical lordosis measurements obtained on supine CT and MRI relative to standing lateral radiographs. Materials and Methods: In this retrospective review, 108 patients who underwent standing lateral radiographs, supine CT, and MRI within a 30-day period were identified. C2–C7 Cobb angles were measured on each modality. Using upright radiographs as the reference standard, the predictive capability of both supine CT and supine MRI in classifying kyphotic versus non-kyphotic alignment was calculated. Results: Standing radiographs demonstrated significantly greater lordosis than supine imaging, with mean paired differences of 6.2° versus CT and 5.0° versus MRI (both p < 0.001); however, strong correlations were observed (with CT: r = 0.75; with MRI: r = 0.72; both p < 0.001). Further, CT-based measurements predicted X-ray Cobb angles with an R² value of 0.57 (estimated X-ray Cobb angle = 8.24 + 0.74 × (CT Cobb angle), β = 0.74, p < 0.001). MRI-based measurements yielded an R² of 0.51 (estimated X-ray Cobb angle = 7.59 + 0.71 × (MRI Cobb angle), β = 0.71, p < 0.001). At threshold ≥ 0°, CT achieved a 100% NPV for excluding kyphosis on upright radiographs. MRI achieved an NPV of 100% when the Cobb angle was >1.20°. Conclusions: Supine CT and MRI systematically underestimate cervical lordosis but demonstrate strong predictive correlation with standing radiographs and reliably exclude true kyphotic alignment, with each achieving near-perfect NPV at defined thresholds. In cases where standing radiographs are unavailable or nondiagnostic, supine imaging modalities such as CT and/or MRI, where the cervical region appears nonkyphotic, can safely rule out cervical kyphosis and inform surgical planning; however, in cases where the cervical region appears kyphotic on CT and/or MRI, standing radiographs remain essential for accurate assessment. Full article