Search Results (23,181)

In fresh produce cold chain last-mile delivery, the highly dispersed customer base leads to exorbitant delivery costs, posing the greatest challenge for cold chain enterprises. Achieving a symmetrical balance between cost-efficiency, environmental sustainability, and service quality is a fundamental pursuit in logistics system optimization. This paper proposes integrating the crowd-shipping logistics model—characterized by internet platform sharing and flexibility—into the delivery service. It incorporates and extends features such as cold chain delivery, mixed fleets using gasoline and diesel vehicles (GDVs), electric vehicles (EVs), partial charging strategies for EVs, and time-of-use electricity pricing into the crowd-shipping model. A joint delivery mode combining traditional professional delivery (using GDVs and EVs) with crowd-shipping is proposed, creating a symmetrical collaboration between centralized fleet management and distributed social resources. The challenges associated with utilizing occasional drivers (ODs) are analyzed, along with the corresponding compensation decisions and allocation-related constraints. A route optimization model is constructed with the objective of minimizing total cost. To solve this model, an Improved Whale Optimization Algorithm (IWOA) is proposed. To further enhance the algorithm’s performance, an adaptive variable neighborhood search is embedded within the proposed algorithm, and four local search operators are applied. Using a case study of 100 customer nodes, the joint delivery mode with OD participation reduces total delivery costs by an average of 24.94% compared to the traditional professional vehicle delivery mode, demonstrating a more symmetrical allocation of logistical resources. The experiments fully demonstrate the effectiveness of the joint delivery model and the proposed algorithm. Full article

Metal Injection Molding (MIM) is based on the processing of highly filled polymers via the well established polymer injection molding process. It offers a highly efficient processing route for the indirect manufacturing of especially small and complex metal parts. In this regard, polyoxymethylene (POM) is often used as a primary binder component in MIM feedstocks due to its high debinding rate through a time-saving catalytic debinding process, utilizing the acid-catalyzed degradation of POM for polymer removal. However, thermally induced degradation of POM under processing conditions can also lead to changes in processing behavior, which is particularly important in highly filled polymers due to their already challenging processability. In this context, the present work demonstrates the impact of POM homopolymers (POM-H) and copolymers (POM-C) with varying viscosities on feedstock characteristics, their influence on the thermal processing stability, and their significance for the properties of the green parts. Within the study, the thermal degradation of both material types was assessed by viscosity measurements and thermogravimetry, with POM-H exhibiting more significant degradation compared to the thermally more stable POM-C, especially at higher temperatures. Catalytic debinding performance was found to be adequate for all materials. However, lower viscosity POM-C grades are preferred to optimize processability in MIM. Full article

The calciothermic reduction slag (CRS) generated in heavy rare earth metal production, is rich in rare earth elements (REE) and highly amenable to recovery. In the present study, the CRS was treated with a H₂SO₄ roasting–water leaching method for the recovery of REEs. The feasibility of this process was confirmed by thermodynamic analysis. Key roasting and leaching factors governing the leaching efficiency of REE were identified and optimized. The maximum REE extraction efficiency reached 94.65% under the optimal conditions: roasting at 150 °C for 240 min with 15 mL of H₂SO₄, followed by water leaching at 20 °C for 60 min at a liquid–solid ratio of 15:1. Results of XRD, SEM, and EDS revealed that the REEs in the CRS were transformed into water-soluble rare earth sulfates after roasting. In the leaching process, the rare earth sulfate is efficiently extracted, whereas CaSO₄ has low solubility in water. A CaSO₄ product with a 98.10% purity was obtained with a calcium recovery of 90.79%, and the removal rate of fluorine in the CRS was 99.99%. The leaching kinetics of the REEs follow a diffusion plus interfacial transfer model with an apparent activation energy of –46.45 kJ·mol⁻¹. This study demonstrates that sulfation roasting–water leaching is a viable route for the comprehensive utilization of CRS. Full article

Glacial lake outburst floods (GLOFs) represent increasingly common and high-magnitude geohazards across the cryosphere of the Tibetan Plateau, particularly under ongoing climate warming and glacier retreat. This study combines multi-temporal remote sensing imagery and detailed Flo-2D hydrodynamic modeling to investigate the erosive dynamics of the 2020 Jinwuco GLOF in Southeastern Tibetan Plateau. Key conclusions include: (1) The 2.35 km-long flood routing channel exhibits pronounced non-uniformity in horizontal curvature, channel width, and cross-sectional shape, significantly influencing flood propagation; five representative cross-sections divide the channel into six distinct segments. (2) Prominent lateral erosion occurred proximally to the dam, attributable to extreme erosive forces and high sediment transport capacity during peak discharge, with horizontal channel curvature further amplifying local impact and erosion. (3) Erosion rates were highest near the dam and in downstream narrow segments, while mid-reach sections with greater width experienced lower erosion. (4) Maximum flow depths reached 28.12 m in topographically confined reaches, whereas peak velocities occurred in upstream and downstream curved sections. (5) The apparent critical erosive shear stress of bank material is controlled not only by soil strength but also by flood dynamics and pre-existing channel morphology, indicating strong feedback between flow dynamics, channel morphology, and critical erosive shear stress of bank material. This study provides a generalized and transferable framework for analyzing GLOF-related erosion in data-scarce high-altitude regions, offering critical insights for hazard assessment, regional planning, and risk mitigation strategies. Full article

Recent studies suggest that Pb-based ammunition could be an important route of Pb exposure for Indigenous Peoples in tropical rainforests. We analyzed blood lead levels (BLL) and isotopic signatures in 111 humans, 97 wild animals, 81 fish, and potential environmental Pb sources in an Indigenous community in the remote and well-preserved Peruvian Amazon with no history of industrial activity. Median BLL was 11.74 μg dL⁻¹, with BLL ≥ 5 µg dL⁻¹ in 95.8% children <12-yo and 94.5% adults. Pb concentrations in wild animals were 7.00 ± 22.40 mg kg⁻¹ DW in liver, 0.06 ± 0.09 mg kg⁻¹ DW in fish muscle tissues, 17.1 ± 10.8 mg kg⁻¹ in soils and 3.4–3.8 mg L⁻¹ in the main river, although 0.43-0.53 mg L⁻¹ were the Pb levels in decanted water used for drinking and cooking. The similarity of isotopic signatures (^207/206Pb and ^208/206Pb) shows that the main Pb sources for humans are river waters (97.6%) and Pb-based ammunition (78.7%). Fish and wildlife act as Pb transporters from water, and wildlife act as Pb transporter from ammunition. Evidence of high human BLL in a remote, non-industrialized Amazonian area demonstrates the urgency of designing regional policies that include health prevention measures, focused on drinking water filtration systems and the use of non-toxic, Pb-free ammunitions. Full article

At the international level, new measures, policies, and technologies are being developed to reduce greenhouse gas emissions and, more broadly, air pollutants. Road transportation is one of the main contributors to such emissions, as vehicles are extensively used in logistics operations, and many fleet owners of fossil-fueled trucks are adopting new technologies such as electric, hybrid, and hydrogen-based vehicles. This paper addresses the Hybrid Fleet Capacitated Vehicle Routing Problem with Time Windows (HF-CVRPTW), with the objectives of minimizing costs and mitigating environmental impacts. A mixed-integer linear programming model is developed, incorporating split deliveries, scheduled arrival times at stores, and a carbon cap-and-trade mechanism. The model is tested on a real case study provided by Decathlon, evaluating the performance of internal combustion engine (ICE), electric (EV), and hydrogen fuel cell (HV) vehicles. Results show that when considering economic and emission trading costs, the optimal fleet deployment priority is to use ICE vehicles first, followed by EVs and then HVs, but considering only total emissions, the result is the reverse. Further analysis explores the conditions under which alternative fuel, electricity, or hydrogen prices can achieve competitiveness, and a further analysis investigates the impact of different electricity generation and hydrogen production pathways on overall indirect emissions. Full article

High-precision spiral trajectory tracking for aquaculture net-cage inspection is hindered by uncertain hydrodynamics, strong coupling, and time-varying disturbances acting on an underactuated autonomous underwater vehicle. This paper adapts and validates a model–data-driven learning-aided adaptive robust control strategy for the specific challenge of high-precision spiral trajectory tracking for aquaculture net-cage inspection. At the kinematic level, a serial iterative learning feedforward compensator is combined with a line-of-sight guidance law to form a feedforward-compensated guidance scheme that exploits task repeatability and reduces systematic tracking bias. At the dynamic level, an integrated adaptive robust controller employs projection-based, rate-limited recursive least-squares identification of hydrodynamic parameters, along with a composite feedback law that combines linear error feedback, a nonlinear robust term, and fast dynamic compensation to suppress lumped uncertainties arising from estimation error and external disturbances. A Lyapunov-based analysis establishes uniform ultimate boundedness of all closed-loop error signals. Simulations that emulate net-cage inspection show faster convergence, higher tracking accuracy, and stronger robustness than classical adaptive robust control and other baselines while maintaining bounded control effort. The results indicate a practical and effective route to improving the precision and reliability of autonomous net-cage inspection. Full article

Sodium metal batteries (SMBs) with ceramic solid electrolytes offer a promising route to improve the energy density of conventional Na-ion batteries (SIBs). Silicate-based ceramics have recently gained attention for their favourable properties, including better ionic conduction and wider stability windows. In this study, 10% Pr³⁺ and Nd³⁺ were doped into sodium gadolinium silicate ceramics to examine the effects on phase purity, ionic conductivity, and interfacial compatibility with sodium metal anodes. The materials were synthesized via solid-state methods and sintered at 950–1075 °C to study the impact of sintering temperature on densification and microstructure. Na₅Gd_0.9Pr_0.1Si₄O₁₂ (NGPS) and Na₅Gd_0.9Nd_0.1Si₄O₁₂ (NGNS) sintered at 1075 °C showed the highest room temperature total ionic conductivities of 1.64 and 1.74 mS cm⁻¹, respectively. The highest critical current density of 0.5 mA cm⁻² is achieved with a low interfacial area-specific resistance of 29.47 Ω cm² for NGPS and 22.88 Ω cm² for NGNS after Na plating/stripping experiments. These results highlight how doping enhances phase purity, ionic conductivity, and interfacial stability of silicates with Na metal anodes. Full article

Due to the complexity of shipyards’ operating scenes and the inconsistency of ship parts’ type and size, current sorting operations for ship parts mainly rely on laborers, resulting in weak control over the production process and key nodes. With the gradual advancement of intelligent manufacturing technology in the shipbuilding process, the trend of machines replacing humans is obvious. In order to promote the automation of the sorting process, intelligent scene recognition and route planning algorithms are needed. In this work, we introduce a localization method based on a laser line profile sensor and ship parts layout analysis algorithm, aiming at obtaining the information needed for sorting route planning. In addition, a heuristic-based route planning algorithm is proposed to solve the built mathematical model of the ship part sorting process. The proposed method can optimize the sorting order of parts, realize stable stacking, shorten sorting distance (taking about 490 m for 43 parts), and thereby improve operation efficiency. These results show that the proposed approach can make intelligent and comprehensible sorting route planning for the ship parts layout. Full article

Climate change has prompted the adoption of sustainable measures to reduce greenhouse gas (GHG) emissions, particularly in urban transportation. The integration of renewable energy sources, such as solar energy, offers a promising strategy to enhance sustainability in urban transit systems. This study assessed solar irradiation along the tram route in Cuenca—an Andean city characterized by distinctive topographic and climatic conditions—with the aim of evaluating the technical feasibility of integrating solar energy into the tram infrastructure. A descriptive, applicative, and longitudinal approach was adopted. Solar irradiation was monitored using a system composed of a fixed station and a mobile station, the latter installed on a tram vehicle. Readings carried out over fourteen months facilitated the analysis of seasonal and spatial variability of the available solar resource. The fixed station recorded average irradiation values ranging from 3.80 to 4.61 kWh/m²·day, while the mobile station reported values between 2.60 and 3.41 kWh/m²·day, revealing losses due to urban shading, with reductions ranging from 14.7% to 18.8% compared to fixed-site values. It was estimated that a fixed photovoltaic system of up to 1.068 MWp could be installed at the tram maintenance depot using 580 Wp panels, with the capacity to supply approximately 81% of the annual electricity demand of the tram system. Complementary solar installations at tram stops, stations, and other related infrastructure are also proposed. The results demonstrate the technical feasibility of integrating solar energy—through fixed and mobile systems—into the tram infrastructure of Cuenca. This approach provides a scalable model for energy planning in urban transport systems in Andean contexts or other regions with similar characteristics. Full article

In this study, a novel and rapid top-down synthesis method for the successful synthesis of few-layered 2D SiC is reported. Since the theoretical prediction of planar and stable 2D SiC with a direct bandgap, only a few experimental methods have overcome the challenging covalent sp³ hybridization of its bulk structure, unlike Van der Waals layered material bonding, making the synthesis of few-layered or mono-layered SiC more difficult due to the highly time- and energy-consuming methods. Moreover, correctly choosing between the more than 250 SiC polytypes increases the complexity of successful approaches to its 2D synthesis. This work reports, for the first time, multi-layered 2D SiC obtained using the wet ultrasonic probe sonochemical exfoliation method, reducing both the experimental synthesis time and energy consumption. Raman spectra showed the size-dependent correlation of the longitudinal optical (LO) mode, and IR showed the bond modification between bulk and nanostructured SiC. These results demonstrate a scalable and facile route for 2D SiC production; therefore, a wide variety of applications can be explored experimentally rather than theoretically, and methods such as the deposition of ScAlN layers onto SiN can be simplified in further studies. Full article

Ti-bearing blast furnace slag (TBS), a byproduct of vanadium–titanium magnetite smelting, serves as an important secondary resource for titanium recovery. However, the complex mineralogical composition and finely dispersed nature of titanium in TBS present significant challenges for efficient extraction. This review systematically examines four major titanium extraction routes: hydrometallurgical leaching, pyrometallurgical smelting, molten salt electrolysis, and selective precipitation, focusing on their limitations and recent improvements. For instance, conventional acid leaching suffers from acid mist release, a colloidal formation that hinders titanium recovery, and waste acid pollution. The adoption of concentrated sulfuric acid roasting activation effectively suppresses acid mist emission and prevents colloidal generation. Pyrometallurgical approaches are hampered by high energy consumption and substantial carbon emissions, which can be alleviated through the use of gaseous reductants to enhance reaction efficiency and reduce environmental impact. Molten electrolysis faces issues such as polarization and undesirable dendritic deposition; these are mitigated by employing liquid metal cathodes integrated with vacuum distillation to achieve high-purity titanium products. Selective precipitation struggles with strict crystallization conditions and low separation efficiency, though advanced techniques like supergravity separation show improved extraction performance. We propose an integrated technical strategy termed “Online conditioning driven by waste heat-mineral phase reconstruction-directional crystallization-optimized liberation.” This approach utilizes the inherent waste heat of slag combined with electromagnetic stirring to enhance homogeneity and promote efficient titanium recovery, offering a sustainable and scalable solution for industrial TBS treatment. Full article

The intelligent development of unmanned aerial vehicles (UAVs) will make power inspection work more convenient. However, challenges such as reliance on precise tower coordinates and the low accuracy in recognizing small targets limit its further development. In this regard, this study proposes an autonomous inspection method based on target detection, encompassing both flight route planning and defect detection. For route planning, the YOLOv8 model is lightly modified by incorporating the VanillaBlock module, the GSConv module, and structured pruning techniques to enable real-time tower detection. Based on the detection results and UAV states, an adaptive route planning strategy is then developed, effectively mitigating the dependence on predefined tower coordinates. For defect detection, the YOLOv8 model is further enhanced by introducing the SPD-Conv module, the CBAM, and the BiFPN multi-scale feature fusion network to improve detection performance for small targets. Compared with multiple baseline models, the computational cost of the improved lightweight model is reduced by 23.5%, while the detection accuracy is increased by 4.5%. Flight experiments further validate the effectiveness of the proposed route planning approach. The proposed fully autonomous inspection method provides valuable insights into enhancing the autonomy and intelligence of UAV-based power inspection systems. Full article

The reintegration of waste into the production chain represents a sustainable method of reducing environmental impact while promoting economic growth. This also aligns with social and environmental demands. In this study, composites were produced from commercial and recycled gypsum, polyvinyl acetate (PVA) emulsions, and chemically treated short green coconut fibers, and characterized by physical and mechanical analyses. The addition of PVA improved paste workability, extended setting time, and reduced porosity, while fiber pretreatment enhanced adhesion and tensile performance. XRD, FTIR, and TGA-DTA confirmed modifications in crystallinity, bonding, and thermal stability due to the combined action of PVA and fibers. Compared with the recycled gypsum reference (RG), the optimized composite (R50C50P5F10) exhibited a 69.1% reduction in sorptivity (from 5440 × 10⁻⁴ to 1680 × 10⁻⁴ kg/m²·s^0.5), a 27.9% increase in flexural tensile strength (from 2.65 to 3.39 MPa), and a 15.1% increase in compressive strength (from 6.18 to 7.12 MPa). Surface hardness values remained statistically equivalent to RG but complied with normative requirements, maintaining all formulations within the moderate hardness category (55–80 Shore C). The results demonstrate the technical feasibility of incorporating recycled gypsum and agro-industrial fibers into gypsum composites, providing a sustainable route for developing more durable construction materials. Full article

Nanoplastics have emerged as significant global pollutants, drawing worldwide concern. Due to their small particle size, large specific surface area, and high surface activity, nanoplastics can combine with other environmental contaminants, including environmental nanoparticles, persistent organic pollutants, antibiotics, and endocrine-disrupting chemicals. This review summarizes recent progress on the environmental behavior of nanoplastics and their complex effects on food safety when co-exposed to various contaminants. These composite pollutants accumulate in foods and the environment, and are ultimately taken up by humans, posing potential toxic effects on human health. In the future, the interaction mechanisms between environmental NPs and various co-contaminants, as well as their transfer routes from food to humans, should be addressed. Full article