Search Results (177)

A rigorous framework for determining actual and minimum boil-up ratios in binary distillation combining analytical mass and energy balances with an extended Ponchon–Savarit graphical approach was implemented. First, global balances across the enriching and stripping sections yield a closed-form expression of the boil-up ratio (V_B) based on enthalpy differences. Second, the V_B was directly determined from an enthalpy–composition diagram by measuring the enthalpy segments between the saturated liquid, vapor, and heat-duty points. Applying this method to high-stage columns confirms that the two methods converge on identical V_B values. Based on these findings, a unified graphical methodology was developed to determine the minimum boil-up ratio (V_Bmin). V_Bmin can be determined on the same diagram by locating the intersections of the extremal tie lines in both the enriching and exhausting sections, analogous to the reflux-pinch points. This procedure was systematically validated across the five canonical feed thermal states. The implemented method is a graphical approach based on the Ponchon–Savarit technique, developed for binary systems. Full article

Soft open point (SOP) offers a viable alternative to traditional tie switches for optimizing power flow distribution between connected feeders, thereby improving power quality and enhancing the reliability of distribution networks (DNs). Among existing medium-voltage (MV) SOP demonstration projects, the modular multilevel converter (MMC) back-to-back voltage source converter (BTB-VSC) is the most commonly adopted configuration. However, MMC BTB-VSC suffers from high cost and significant volume, with device requirements increasing substantially as the number of feeders grows. To address these challenges, this paper proposes a novel star-connected cascaded H-bridge (CHB) STATCOM SOP (SCS-SOP). The SCS-SOP integrates the static synchronous compensator (STATCOM) and low-voltage (LV) BTB-VSC into a single device, enabling reactive power support within feeders and active power exchange between feeders, while achieving reduced component cost and volume, simplified power decoupling control, and increasing power quality management capabilities. The topology derivation, configuration, operational principles, and control strategies of the SCS-SOP are elaborated. Finally, simulation and experimental models of a two-port 3 Mvar/300 kW SCS-SOP are developed, with results validating the theoretical analysis. Full article

Steel fiber-reinforced concrete (SFRC) exhibits superior tensile and flexural strengths, crack resistance, compressive toughness, and ductility. These characteristics make SFRC attractive for precast beam joints, shear-critical regions without stirrups, and retrofitted overlays, thereby enabling composite members. However, the shear and flexural responses of such members often differ from monolithically cast elements. To clarify these effects, nine composite specimens and one cast-in-place control were tested under four-point bending. Key parameters, including load-bearing capacity, failure evolution, and failure modes, were documented, together with load–deformation behavior, reinforcement strains, and concrete deformations. Results showed that horizontal joints reduced shear resistance and altered crack propagation compared to monolithic beams. Incorporating 1.0% hooked-end steel fibers improved both shear and flexural performance. SFRC above the joint was more effective for shear, while SFRC in both zones improved flexure. The fully SFRC specimen without stirrups achieved 63% higher shear capacity than its NC counterpart, with ductility rising from 2.2 to 3.1. A 1.0% fiber dosage provided shear resistance equivalent to D8@200 stirrups, confirming the potential of SFRC to reduce transverse reinforcement. Analytical models, including a fiber beam–column element and strut-and-tie approach, showed reasonable agreement with experiments. Full article

This study evaluates the corrosion behavior of Fe-22Mn-0.6C TWIP steels containing 0%, 5%, and 10% chromium after 28 days of exposure to a neutral sulfate solution. By combining electrochemical testing with a surface and spectroscopic analysis, we explored how Cr influences the formation and stability of oxide layers. The results reveal a clear trend: as the chromium content increases, the corrosion resistance improves significantly. The 10% Cr alloy stood out for its high impedance and stable electrochemical response, pointing to the development of a dense, protective oxide layer that limits the corrosive attack. The SEM/EDS and Raman spectroscopy revealed that chromium not only enhances the oxide’s compactness but also alters its composition, transitioning from iron-rich, porous oxides to Cr-containing spinels and oxyhydroxides with superior barrier properties. These structural and chemical improvements were confirmed by electrochemical parameters, which showed a reduced capacitance and increased film homogeneity. To tie these findings together, we propose a schematic model describing how chromium shapes the passivation process in these steels. Altogether, this study highlights the essential role of Cr in enhancing long-term corrosion protection in high-Mn TWIP steels under sulfate-rich conditions. Full article

Cattle marketed through auction market systems and/or that remain unvaccinated are considered higher risk for BRD, but impacts on host response remain unclear. We sought to identify specific genomic patterns of beef calves vaccinated against BRD viruses or not and commercially marketed or directly transported in a split-plot randomized controlled trial. Forty-one calves who remained clinically healthy from birth through backgrounding were selected (randomly stratified) from a larger cohort of cattle (n = 81). Treatment groups included VAX/DIRECT (n = 12), VAX/AUCTION (n = 11), NOVAX/DIRECT (n = 7), and NOVAX/AUCTION (n = 11). Blood RNA was acquired across five time points, sequenced, and bioinformatically processed via HISAT2 and StringTie2. Significant transcriptional changes (FDR < 0.05) were observed at backgrounding entry (T5) in NOVAX/AUCTION cattle exhibiting 2809 uniquely differentially expressed genes and relative activation of immune, inflammatory, and metabolic pathways with upregulation of interferon-stimulated genes (e.g., IFIT3, MX2, and TRIM25) and downregulation of specialized proresolving mediator (SPM) enzymes (ALOX5 and ALOX15). VAX/AUCTION cattle exhibited modulated immune activation and preserved expression of SPM-associated genes when compared to NOVAX/AUCTION cattle. Both marketing route and vaccination shape the molecular immune landscape during high-stress transitions, with preweaning vaccination potentially modulating this response. This study provides mechanistic insight into how management practices influence immunological resilience and highlights the value of integrating transcriptomics into BRD risk mitigation. Full article

Reinforced concrete (RC) deep beams constructed with low-strength concrete are susceptible to sudden splitting failures in the strut region due to shear–compression stresses. To mitigate this vulnerability, various strengthening techniques, including steel plates, fiber-reinforced polymer sheets, and cementitious composites, have been explored to confine the strut area. This study investigates the structural performance of RC deep beams with low-strength concrete, strengthened externally using an Engineered Cementitious Composite (ECC) layer. To ensure effective confinement and uniform shear distribution, shear reinforcement was provided at equal intervals with configurations of zero, one, and two vertical shear reinforcements. Four-point bending tests revealed that the ECC layer significantly enhanced the shear capacity, increasing load-carrying capacity by 51.6%, 54.7%, and 46.7% for beams with zero, one, and two shear reinforcements, respectively. Failure analysis through non-linear finite element modeling corroborated experimental observations, confirming shear–compression failure characterized by damage in the concrete struts. The strut-and-tie method, modified to incorporate the tensile strength of ECC and shear reinforcement actual stress values taken from the FE analysis, was used to predict the shear capacity. The predicted values were within 10% of the experimental results, underscoring the reliability of the analytical approach. Overall, this study demonstrates the effectiveness of ECC in improving shear performance and mitigating strut failure in RC deep beams made with low-strength concrete. Full article

The downwelling light sensor (DLS) is the industry-standard solution for generating UAV-based digital orthophoto maps (DOMs). Current mainstream DLS correction methods primarily rely on angle compensation. However, due to the temporal mismatch between the DLS sampling intervals and the exposure times of multispectral cameras, as well as external disturbances such as strong wind gusts and abrupt changes in flight attitude, DLS data often become unreliable, particularly at UAV turning points. Building upon traditional angle compensation methods, this study proposes an improved correction approach—FIM-DC (Fitting and Interpolation Model-based Data Correction)—specifically designed for data collection under clear-sky conditions and stable atmospheric illumination, with the goal of significantly enhancing the accuracy of reflectance retrieval. The method addresses three key issues: (1) field tests conducted in the Qingpu region show that FIM-DC markedly reduces the standard deviation of reflectance at tie points across multiple spectral bands and flight sessions, with the most substantial reduction from 15.07% to 0.58%; (2) it effectively mitigates inconsistencies in reflectance within image mosaics caused by anomalous DLS readings, thereby improving the uniformity of DOMs; and (3) FIM-DC accurately corrects the spectral curves of six land cover types in anomalous images, making them consistent with those from non-anomalous images. In summary, this study demonstrates that integrating FIM-DC into DLS data correction workflows for UAV-based multispectral imagery significantly enhances reflectance calculation accuracy and provides a robust solution for improving image quality under stable illumination conditions. Full article

In the production of a digital orthophoto map (DOM) from unmanned aerial vehicle (UAV)-acquired overlapping images, some anomalies such as texture stretching or data holes frequently occur in water areas due to the lack of significant textural features. These anomalies seriously affect the visual quality and data integrity of the resulting DOMs. In this study, we attempted to eliminate the water surface anomalies in an example DOM via replacing the entire water area with an intact one that was clipped out from one single UAV image. The water surface scope and boundary in the image was first precisely achieved using the multisource seed filling algorithm and contour-finding algorithm. Next, the tie points were selected from the boundaries of the normal and anomalous water surfaces, and employed to realize their spatial alignment using affine plane coordinate transformation. Finally, the normal water surface was overlaid onto the DOM to replace the corresponding anomalous water surface. The restored water area had good visual effect in terms of spectral consistency, and the texture transition with the surrounding environment was also sufficiently natural. According to the standard deviations and mean values of RGB pixels, the quality of the restored DOM was greatly improved in comparison with the original one. These demonstrated that the proposed method had a sound performance in restoring abnormal water surfaces in a DOM, especially for scenarios where the water surface area is relatively small and can be contained in a single UAV image. Full article

Photogrammetry can be a valuable tool for understanding landscape evolution and natural hazards such as landslides. However, factors such as vegetation cover, shadows, and unstable ground can limit its effectiveness. Using photos across time to monitor an area with unstable or changing ground conditions results in fewer tie points between images across time, and often leads to low comparative accuracy if single-epoch (i.e., classical) photogrammetric processing approaches are used. This paper presents a study evaluating the co-alignment approach applied to fixed terrestrial timelapse photos at an active landslide site. The study explores the comparative accuracy of reconstructed surface models and the location and behavior of tie points over time in relation to increasing levels of global change due to landslide activity and rockfall. Building upon previous work, this study demonstrates that high comparative accuracy can be achieved with a relatively low number of inter-epoch tie points, highlighting the importance of their distribution across stable ground, rather than the total quantity. High comparative accuracy was achieved with as few as 0.03 percent of the overall co-alignment tie points being inter-epoch tie points. These results show that co-alignment is an effective approach for conducting change detection, even with large degrees of global changes between surveys. This study is specific to the context of geoscience applications like landslide monitoring, but its findings should be relevant for any application where significant changes occur between surveys. Full article

The use of high-resolution satellite stereo pairs for dense image matching is a core technology for the low-cost generation of large-scale digital surface models (DSMs). However, water areas in satellite imagery often exhibit weak texture characteristics. This leads to serious issues in reconstructing water surface DSMs with traditional dense matching methods, such as significant holes and abnormal undulations. These problems significantly impact the intelligent application of satellite DSM products. To address these issues, this study innovatively proposes a water region DSM reconstruction method, boundary plane-constrained surface water stereo reconstruction (BPC-SWSR). The algorithm constructs a water surface reconstruction model with constraints on the plane’s tilt angle and boundary, combining effective ground matching data from the shoreline and the plane constraints of the water surface. This method achieves the seamless planar reconstruction of the water region, effectively solving the technical challenges of low geometric accuracy in water surface DSMs. This article conducts experiments on 10 high-resolution satellite stereo image pairs, covering three types of water bodies: river, lake, and sea. Ground truth water surface elevations were obtained through a manual tie point selection followed by forward intersection and planar fitting in water surface areas, establishing a rigorous validation framework. The DSMs generated by the proposed algorithm were compared with those generated by state-of-the-art dense matching algorithms and the industry-leading software Reconstruction Master version 6.0. The proposed algorithm achieves a mean RMSE of 2.279 m and a variance of 0.6613 m² in water surface elevation estimation, significantly outperforming existing methods with average RMSE and a variance of 229.2 m and 522.5 m², respectively. This demonstrates the algorithm’s ability to generate more accurate and smoother water surface models. Furthermore, the algorithm still achieves excellent reconstruction results when processing different types of water areas, confirming its wide applicability in real-world scenarios. Full article

Straw as a building material alternative is in line with sustainable development goals. To make effective use of straw resources such as rice and corn stalks in rural areas, a kind of steel wire mesh-reinforced straw concrete sandwich panel (SCSP) was developed. The SCSP was composed of cold-drawn low-carbon steel-wire mesh (SWM), fine gravel concrete (FGC), and straw. The used type of FGC was shotcrete. A cold-drawn low-carbon SWM was arranged on the upper and lower sides of the SCSP, and a vertical wire tie was arranged between the upper and lower cold-drawn low-carbon SWMs. The FGC was sprayed on the SWM to make the SCSP layer work together. The loading process of the SCSP could be divided into three stages: elastic working state, cracking state, and failure state. The results of the four-point loading test show that the maximum flexural moment of the SCSP can be up to 7.5 kN·m in the elastic range. The ultimate bearing capacity of SCSP reaches 10.9 kN·m, and the maximum crack width can reach 3~4 mm. At the same time, based on the assumption of the flexural section of SCSP, two simplified calculation models of SCSP bearing capacity were established. The average error was 2.99% and 9.41%, respectively, by comparing the experimental values with the two calculated values. The results obtained by using the two models were in good agreement with the experimental results. Full article

Thermoplastic injection molding is a widely used process for producing complex three-dimensional plastic parts with tight dimensional tolerances. A key determinant of part quality is the switchover point—the transition from velocity-controlled filling to pressure-controlled packing. This transition affects critical product attributes, such as d imensional accuracy, weight consistency, and surface finish. Precise control of the switchover point enhances process stability, robustness, and adaptability. This review consolidates recent advancements in switchover methods and adaptive control techniques. Improvements in traditional methods include the use of pressure gradient detection to mitigate viscosity variations and adaptive control to refine stroke- and time-dependent switchovers. In addition, deformation-based strategies detect the mold-opening force associated with cavity pressure through clamping force, mold separation, or tie-bar elongation. The integration of machine learning and feature extraction techniques enables the real-time adjustment of the switchover point by mapping relationships between process parameters and quality criteria. In addition, ultrasonic sensors provide non-invasive melt front detection, reducing the risk of mold damage. Real-time simulations, updated through nozzle pressure feedback, complement these methods to achieve precise switchover timing. This review also identifies persistent challenges, such as sensitivity to material properties, machine wear, and environmental conditions, and it explores future directions for improving the accuracy and adaptability of switchover control in modern injection molding processes. Full article

The blueberry fruit (Vaccinium corymbosum L.) exhibits a high content of bioactive compounds, including anthocyanins, that can be used as pigmenting agents, but they are mixed with sugars, which can hinder their utilization. The objective was to evaluate the use of aqueous two-phase extraction aided by centrifugation to separate bioactive compounds, particularly anthocyanins, from blueberry fruits, considering the reduction of sugars, for their use as pigmenting agents in a food product. A mixture of trisodium citrate (Na₃C₃H₅O(COO)₃; Na₃Cit) and polyethylene glycol ([HO-(CH₂CH₂O)n-CH₂OH]; poly (ethane-1,2-diol); PEG) with a molecular weight of 4 kDa was used. Based on the cloud point method, a binodal diagram was developed. After the evaluation of several systems with composition located on a tie line, conditions were identified to form biphasic systems with phases of equal volume. Passive sedimentation for 0, 15, and 30 min, followed by centrifugation and also passive sedimentation for 24 h without centrifugation, were evaluated. A system with 17.73% Na₃Cit, 21.33% PEG, 30 min of passive sedimentation, and 15 min of centrifugation at 2940× g produced an extract with a high concentration of soluble phenols (0.353 mg/mL) and anthocyanins (0.202 mg/mL) and, likewise, high antioxidant activity (910.0 mmol gallic acid equivalents per mL), with reduced sugar content, which demonstrated to have the potential to pigment food beverages with a reddish tone. Full article

This study established a real-time measurement system to monitor the melt quality in an injection molding process using a pressure sensor installed on the nozzle and a strain gauge installed on the tie bar. Based on the sensing curves from these two external sensors, the characteristic values of nozzle pressure and clamping force were used to optimize parameters. This study defined product weight as a quality indicator and developed a scientific molding parameter setup process. The optimization sequence of parameters is injection speed, V/P switchover point, packing pressure, packing time, and clamping force. Finally, an adaptive process control system was established based on the online quality characteristic values to maintain product quality consistency. Continuous production experiments were conducted at two sites to verify the system’s effectiveness. The results revealed that the optimized process parameters can ensure product weight stability during long-term production. Furthermore, using the adaptive process control system further enhanced product weight stability at both sites, reducing the standard deviation of product weight to 0.0289 g and 0.0148 g, and the coefficient of variation to 0.065% and 0.035%, respectively. Full article

To mitigate voltage limit issues in the operation of a novel electromagnetic voltage regulation device, this paper presents a flexible loop-closing control strategy with voltage optimization. The approach uses a two-stage path optimization: in the first stage, the voltage phase at the loop-closing point is adjusted to ensure smooth operation, while in the second stage, the voltage magnitude is optimized to prevent voltage limits and achieve seamless regulation. By integrating phase angle difference calculations with coordinated rotation angle control, the simulation results show that this strategy reduces loop-closing current by approximately 95.87% compared to direct loop closing, decreases voltage fluctuations by around 50.0% compared to traditional methods, and shortens operation time by 40.14%. This approach significantly enhances system stability and response speed, effectively addressing the issue of excessive loop-closing current caused by voltage deviations at distribution network tie switches. Full article