Search Results (1,042)

This study investigates the shear behavior of glass fiber-reinforced polymer (GFRP)-reinforced concrete (RC) beams to address challenges associated with their low elastic modulus, absence of yielding, and reduced stirrup efficiency in bending regions. GFRP bars are increasingly adopted as an alternative to steel due to their superior corrosion resistance, durability, and cost-effectiveness. This study focuses on the effects of stirrup type, stirrup spacing, and shear span-to-effective depth ratio on the structural performance of GFRP RC beams. Twelve full-scale beams were tested under four-point bending, incorporating three GFRP shear reinforcement configurations: fabricated closed stirrups, integrated straight bar systems, and discrete vertical bars. Experimental observations were analyzed in terms of failure modes, load-carrying capacity, energy absorption, and deformation characteristics. Results indicate that fabricated F-type stirrups provide the highest shear performance, though their effectiveness is limited by premature rupture at bending points. Site-integrated S- and T-type configurations offer practical alternatives, maintaining structural integrity while mitigating bend-related stress concentrations, but with slightly lower energy absorption and load capacity. Increasing stirrup spacing significantly reduces shear resistance and shifts failure from flexural to shear-dominated modes. Comparisons with widely used design codes and analytical models show that CSA S806-12 provisions offer the most reliable predictions, while other guidelines tend to over- or underestimate shear capacity depending on configuration and a/d ratio. The study highlights the importance of optimizing stirrup type and spacing to enhance the shear performance of GFRP RC beams. Findings provide valuable insights for improving current design methodologies, offering guidance for engineers seeking durable, corrosion-resistant alternatives to steel reinforcement in aggressive environments. This research demonstrates that innovative site-integrated stirrup configurations can bridge practical fabrication constraints without compromising overall shear performance, promoting more efficient and resilient GFRP RC structures. Full article

Compared to antennas bearing a single port, MIMO antennas with several ports enable higher data throughput by exploiting spatial diversity. This capability is essential for next-generation implantable medical devices, where high channel capacity is a key requirement. A quad-element implantable MIMO antenna is designed and practically validated at 1420 MHz in this paper. It occupies a compact volume of $7\times 8\times 0.1 {\mathrm{mm}}^3$ ($5.6 {\mathrm{mm}}^3$). The compactness is realized by combining high-permittivity substrate (Rogers 3010 with relative permittivity of 10.2) with meandered radiator paths, which increase the effective current length while maintaining a small physical size. All antennas have very small mutual coupling with isolation of more than $31.78$ dB, which is mainly due to the spacing of 1 mm between the elements and the substrate, which is thin. The peak realized gain for each antenna element is $-27.3$ dBi. The simulation is performed within a capsule-like structure, which is embedded in the stomach tissue model. The experimental verification is carried out by embedding antenna within minced meat. The ECC, channel capacity, and link margin are also evaluated and found to be satisfactory. The proposed antenna ensures reliable communication performance, with the transmission range being as high as $2.5$ m, link margin being 15 dB, and the data rate being 120 Mb/s. The proposed antenna ensures a good level of ECC, which is less than $0.1$. The SAR is $52.3$ W/kg at 1420 MHz. This design is favorable for implants because of the small size, good impedance matching, high isolation, low correlation, good level of gain, and good link performance. Full article

With the rapid transition of power transmission systems toward higher capacity, longer distance, and improved efficiency, aluminum alloys from the 6xxx (Al–Mg–Si) and 8xxx (Al–Fe) series have become key structural materials for overhead conductors and power cables due to their low density, cost effectiveness, and favorable strength–conductivity balance. Compared with traditional steel-reinforced conductors, optimized aluminum alloy conductors can reduce structural weight by approximately 30–40% and installation cost by about 20–30%, while maintaining comparable current-carrying capacity. This review systematically focuses on modification methods and research progress of aluminum alloy cores for electric wires and cables. The strengthening characteristics of 6xxx alloys (heat-treatment responsiveness and precipitation strengthening) and the creep-resistance stability of 8xxx alloys are comparatively analyzed. Four core performance requirements—high electrical conductivity, mechanical strength, creep resistance, and corrosion resistance—are summarized as evaluation criteria for conductor applications. Particular emphasis is placed on three major modification strategies: (1) microalloying (e.g., Zr, Sc, rare earth elements) for precipitation and dispersoid stabilization; (2) thermomechanical process optimization for grain refinement and strength–conductivity balance; (3) composite reinforcement for high-temperature and ultra-high-strength applications. Quantitative literature data indicate that microalloying and process optimization typically achieve 15–40% strength improvement with conductivity variation within 3–5% IACS, while composite strategies may provide 30–80% strength enhancement but often at the expense of 5–20% conductivity reduction. The distinct applicability of 6xxx and 8xxx alloys under different service conditions is clarified, providing guidance for conductor material selection. Finally, future research directions—including precise composition–process integration, advanced thermomechanical control, and scalable modification technologies—are proposed to support high-performance, cost-effective, and large-scale deployment of aluminum alloy conductors. Full article

This paper presents an experimental investigation of dynamic line rating (DLR) applied to aluminium conductor steel-reinforced (ACSR) overhead line conductors, with a specific focus on wind speed conditions up to 5 m/s. An experimental system was designed and implemented to provide controlled and repeatable cross-flow air conditions along a tested ACSR conductor, enabling direct measurement of wind speed in the immediate vicinity of the conductor surface. Conductor temperature, electrical current, voltage drop per unit length, the phase angle between them, and relevant meteorological parameters were continuously measured under controlled experimental conditions. Based on the measured data, the conductor heat balance was evaluated and the allowable current-carrying capacity was determined. The experimentally obtained conductor temperatures and ampacity values were compared with results calculated using thermal models and correlations recommended by IEEE, CIGRÉ, and IEC standards. The comparison demonstrates that, under low and moderate wind speed conditions, differences between standard-based predictions and experimental results can be significant, leading to deviations in the estimation of allowable current-carrying capacity. The results confirm the high sensitivity of DLR calculations to wind-related assumptions and provide an experimentally validated basis for assessing the applicability and limitations of existing standard thermal models for ACSR conductors under realistic operating conditions. Full article

In large-scale offshore wind power transmission systems, the offshore converter valves are typically based on the half-bridge Modular Multilevel Converter (MMC) topology. This design leads to considerable weight and high costs, presenting a critical bottleneck for the development of offshore wind power transmission. This paper proposes a hybrid topology consisting of paralleled MMCs connected in series with a Diode Rectifier Unit (DRU) to achieve lightweight offshore converter valves. The parallel configuration enhances the steady-state current-carrying capacity of the valve group to match the DRU valve group, and power balance among the paralleled MMCs is realized through an additional DC current-sharing control loop. A calculation method for the main circuit parameters of this lightweight topology is presented, along with a complete parameter calculation process. A design example based on actual engineering capacity is provided. PSCAD simulation results verify that the electrical quantities during steady-state operation of the hybrid topology are consistent with the designed parameters, confirming the correctness of the proposed parameter calculation method. Full article

In light of the global issue of “Carbon Neutrality”, a high proportion of renewable energy integrated into modern power systems has become the key to energy strategic transformation, which has escalated the demand for high-gain, high-power converters for DC energy conversion. In this paper, a non-isolated double-layer multi-port parallel-connected high-gain DC–DC conversion system has been proposed. The system consists of two energy layers: the upper layer is designed as a non-isolated high-gain three-port DC conversion topology, which includes two energy inputs and one output port, and the bottom layer is a three-port constant current output module. The output ports of these layers are connected in parallel, while the input ports are independent. Thus, both high output voltage gain and power capacity were fulfilled for the renewable power application condition. The system is capable of operating in both input-parallel–output-parallel (IPOP) and multi-input–independent-output-parallel (MIIOP) modes, thereby enabling multi-port high-gain DC power conversion. Detailed analysis of the operation strategies under a switching cycle for both energy layers is presented. A small signal was introduced to establish the mathematical model of both energy topologies. In order to simultaneously regulate the output voltage and achieve dynamic current sharing between the layers, an adaptive current-sharing control strategy was developed based on the established system models. The proposed control strategy can control the output voltage through the upper-layer topology and dynamically allocates output current between the layers based on the output power level, which will effectively enhance the system’s power rating. The simulation mode was built in the PSIM environment, open-loop simulations were carried out for obtaining system characteristics, and closed-loop simulations were conducted for control efficiency validation. Finally, a 2000-W experimental prototype was developed based on the digital control center dsPIC33FJ64GS606. Open-loop and closed-loop experiments were carried out for system performance evaluation. Both simulation and experimental results successfully evaluated the power transfer performance and control system performance of the proposed system, and a peak efficiency of 95.7% under 10 times voltage gain was achieved. Full article

Sustainable spatial development requires land-use allocation that aligns with reflects the environment’s biophysical capacity. However, rapid urbanization and agricultural expansion often result to spatial mismatches between land utilization and land capability, the reby increasing environmental degradation and disaster vulnerability. East Java Province, one of Indonesia’s most densely populated regions, has experienced significant land-use transformation driven by demographic pressure and economic development. This study aims to evaluate the environmental carrying capacity by assessing the spatial compatibility among land capability, existing land use, and the Provincial Spatial Plan (RTRWP) using a Geographic Information System (GIS)-based analytical approach. Land capability was determined based on key biophysical parameters, including slope gradient, soil texture, drainage conditions, erosion susceptibility, effective soil depth, and flood hazard. Spatial overlay analysis was employed to identify areas of conformity and mismatch between land capability and both current and planned land uses. The results indicate that only approximately 52% of the provincial area is utilised in accordance with its land capability. In comparison, the remaining 48% exhibits varying degrees of spatial mismatch. Erosion is identified as the dominant limiting factor, affecting more than 43% of the region, particularly in mountainous and hilly landscapes. Furthermore, over 60% of East Java falls within Land Capability Classes III–VII, indicating moderate to severe environmental constraints on limitations intensive land use. High levels of spatial mismatch are concentrated in the southern upland districts—such as Pacitan, Trenggalek, southern Malang, and Lumajang, which are highly susceptible to landslides, as well as in the northern lowland corridor, including the Surabaya–Gresik–Sidoarjo metropolitan region, which faces a significantly flood risk. These findings suggest that land-use practices exceeding environmental carrying capacity substantially amplify disaster risk. Therefore, integrating land capability assessment into spatial planning and zoning regulations is essential and for promoting ecosystem-based disaster risk reduction and achieving sustainable spatial development in East Java Province. Full article

Longitudinal shuttle-shaped concrete-filled steel column with cruciform sections (LSS-CFST-CS) is highly valued by architects and structural engineers for its distinctive appearance and significant architectural impact in spatial steel structures. However, there are currently no available studies addressing the buckling behavior, load-carrying capacity, and strength design methods of such structures. This study numerically investigates the elastic buckling behavior, load-carrying capacity, and design methods of LSS-CFST-CS under axial compression, as well as under combined axial compression and bending moment. First, closed-form solutions for the elastic buckling load under axial compression are derived for a pinned–pinned tapered concrete-filled steel column (TCFST) with cruciform sections and standard LSS-CFST-CS, respectively. The resulting solutions are validated against finite element (FE) numerical results from a wide range of LSS-CFST-CS examples, and the corresponding buckling modes are examined. Next, a unified expression for the elastic buckling load under axial compression is established for both types of TCFST and standard LSS-CFST-CS. Finally, a parametric study incorporating initial geometric imperfections is conducted to investigate the load-carrying capacity of LSS-CFST-CS and to quantify the influence of key parameters on stability capacity. On this basis, design recommendations for the stability capacity are proposed for axial compression and combined axial compression and bending moment of LSS-CFST-CS, respectively. Full article

White mold caused by Sclerotinia sclerotiorum (Lib.) de Bary continues to threaten yield and quality and remains a stubborn, sometimes unpredictable constraint in many cropping systems. The pathogen’s broad host range and its capacity to persist for years as sclerotia mean that fields can carry risk long after visible symptoms fade. Disease development is often driven by short windows of favorable temperature and moisture that promote germination and ascospore release and dispersal, while myceliogenic infection from soil-borne sclerotia can also initiate disease directly. Yet dependable control is still undermined by durable inoculum, limited stable host resistance, variable biocontrol performance, and shrinking chemical options together with fungicide resistance risk. Here we consolidate current understanding and ongoing uncertainties around sclerotial formation and germination cues, the environmental drivers that shape epidemic onset, and the processes governing host colonization, including the roles of cell wall-degrading enzymes, oxalic acid, and redox regulation, as well as the continuing debate over necrotrophic versus hemibiotrophic phases. Management is considered from a practical perspective, covering cultural risk reduction, forecasting-guided fungicide programmes supported by resistance-management principles, and biological control strategies targeting sclerotia. Across systems, the evidence points to the same lesson: single tactics rarely remain reliable under field variability, whereas integrated packages that reduce soil inoculum and align interventions with risk are more durable. Future priorities include resolving early infection events, improving prediction of carpogenic germination under changing climates, increasing the consistency of biocontrol, and accelerating resistance breeding supported by genomic resources. Full article

Lithium–sulfur (Li–S) batteries have emerged as a promising next-generation energy storage solution as the capacity demands on lithium-ion systems begin to exceed practical limits. In a global push for renewable energy and sustainable practices, Li–S technology offers several compelling advantages. Both lithium and sulfur are relatively inexpensive (especially compared to the transition metals used in lithium-ion cells), and Li–S batteries are easier and less costly to recycle. Moreover, Li–S chemistry carries a theoretical energy density about five times greater than that of current lithium-ion batteries, making it attractive for high-energy-density applications. Because of these advantages, research interest in Li–S batteries remains high despite significant challenges that still limit their performance and lifespan. However, despite these advantages, several fundamental challenges limit the practical deployment of Li–S batteries, including the polysulfide shuttle effect, large volume expansion of sulfur during cycling, low intrinsic electrical conductivity of sulfur and its discharge products, and instability of the lithium metal anode caused by dendrite formation. This paper explains the working principles of Li–S batteries, analyzes the key challenges and recent achievements in their development, and surveys various mechanical engineering applications for which Li–S batteries are being explored, as well as prospects for their future commercialization and sustainability. Full article

Poly(amidoamine) (PAMAM) and poly-L-lysine (PLL) dendrimers have emerged as highly versatile macromolecular platforms with significant potential in biomedical applications, owing to their well-defined architecture, tunable surface chemistry, and capacity for multivalent functionalization. Their ability to carry substantial molecular payloads and to be engineered for selective interactions with biological systems has positioned them as attractive candidates for targeted drug delivery, including the transport of boron-rich compounds. Recent advances in dendrimer chemistry have enabled the incorporation of boron clusters into PAMAM and PLL structures, creating hybrid systems designed to enhance cellular uptake, improve tumor selectivity, and increase boron accumulation within malignant tissues. Given the growing interest in boron neutron capture therapy (BNCT), the integration of boron clusters into dendrimer structures represents a particularly promising direction for enhancing boron delivery to tumors. This manuscript reviews current knowledge on PAMAM and PLL dendrimers and their boron-functionalized derivatives, summarizing findings from cell culture studies, in vivo models, and clinical or preclinical investigations. Particular attention is given to both the advantageous properties of these dendrimers—such as improved delivery efficiency and biocompatibility—and their potential undesirable biological effects. As such, PAMAM and PLL dendrimers represent an important and evolving class of carriers that may significantly advance the effectiveness of boron neutron capture therapy (BNCT) in cancer treatment. Full article

The suction pile–gravity hybrid foundation (SPGH) has emerged as a novel foundation for floating wind turbines (FWTs) due to its superior bearing mechanism. In harsh marine environments, offshore wind turbine structures endure multidirectional wave–wind current loads, which are transmitted through mooring systems as complex multidirectional coupled loads (horizontal, vertical, bending moments, and torque), imposing severe challenges to the bearing capacity. Therefore, this study carries out 3D finite element simulations, utilizing the Hardening Soil–Small Strain constitutive model to simulate the stress–strain behavior of sand, to systematically investigate the failure modes and bearing capacity of SPGH foundations. The method underlying the failure envelope theory is proposed, applicable to tension-leg mooring systems (dominated by uplift and lateral loads) and catenary mooring systems (dominated by compression and lateral loads). Results indicate that under pure vertical uplift or torque loading, both SPGH and traditional SP foundations exhibit typical interfacial shear failure modes. Under pure horizontal or bending moment loading, SPGH and SP foundations exhibit rotational instability failure. The direction of vertical load has a significant impact on the bearing performance of SPGH foundations. In addition, horizontal load can increase its vertical uplift-bearing capacity by 46% and torque capacity by 48%. The enhancement effect of the bending moment load is more significant, and can increase the vertical uplift-bearing capacity by 115% and the torque-bearing capacity by 112%, respectively, while vertical downward loads within a certain range significantly improve horizontal and bending-bearing performance. Full article

The evaluation of resources and environmental carrying capacity (RECC) is of great significance for achieving harmony between humans and resources and the environment to realize sustainable development. However, current research has not reached a consensus on the research objects, theories, and methods for RECC evaluation. Therefore, this study defined the research object of regional RECC evaluation and designed an evaluation process for regional RECC based on the mutation progression method developed from the mutation theory. Then, the RECCs of 16 cities in Shandong Province during 2013–2022 were calculated, and their temporal and spatial evolution characteristics were analyzed. The result shows that: (1) the research object of regional RECC evaluation is essentially the concentrated reflection of the interaction between resources, the environment, the economy, and society; (2) the process of “construct a multilevel evaluation index system–determine the mutation types of the evaluation index system–standardize the lowest level indexes–evaluate the comprehensive regional RECC” could provide reference for RECC evaluation; and (3) from 2013 to 2022, the RECC in Shandong Province showed a steady increasing trend, and the RECC in eastern and central areas in Shandong Province was relatively higher. By analyzing these results, we found that the natural background conditions, the mode of production and life, and the decisions of the central government are the important factors affecting regional RECCs. Full article

This study examines the e-waste management practices in Sri Lanka, using a comparative approach that considers the entire e-waste management supply chain. A systematic review was carried out by examining the existing policy implementations and regulations and the current formal and informal waste management practices established in Sri Lanka and by comparing collection levels globally and across selected developed and developing countries. This study demonstrates how regulatory bodies currently intervene from manufacturing to the end of product life and how stakeholders are involved in e-waste management. This work reveals the policy, regulations, and institutional capacity gaps in establishing proper e-waste management in Sri Lanka. While Sri Lanka faces some similar challenges to other developing countries, like dependence on informal collection, differences in policy frameworks, and institutional capacity, this may imply that generalized solutions fail to capture some important national variations. Full article

The development of energy-efficient conductors capable of operating reliably in harsh, cold climates is crucial for sustainable power infrastructure. High-mountain and cold regions are key research scenarios for energy-saving conductors, enabling the natural enhancement of conductor heat dissipation in low-temperature environments and improving the current carrying capacity and energy efficiency. These regions are rich in renewable energy and urgently need efficient transmission channels. However, the extremely complex working conditions create strict requirements for the thermal–mechanical coupling performance of conductors, and existing research has paid insufficient attention to this. This study evaluates the thermal and mechanical performance of three advanced energy-saving conductors (JLHA3-275, JL1/G1A-240/30, JL/LHA1-135/140) in comparison with a conventional conductor (JL/G1A-240/30) under cold-region operating conditions. A finite element analysis model, validated against theoretical calculations under combined meteorological factors, was employed to simulate radial temperature fields and stress distribution. The results demonstrate that the JLHA3 conductor exhibits superior heat dissipation and minimal resistive losses, maintaining a radial temperature of −23.35 °C under a 700 A load, approximately 1.6 °C lower than the conventional type. Its temperature further decreases significantly with increased wind speeds. Thermally, JLHA3 shows high stability across a broad temperature range (−28.85 °C to 29.03 °C). Mechanically, it displays uniform stress distribution and a notable decrease in stress from 79.53 MPa to 39.46 MPa with rising temperatures, indicating excellent flexibility and thermal adaptability. These findings confirm that the JLHA3 conductor offers an optimal combination of thermal performance, structural reliability, and energy efficiency for high-altitude, cold-region power transmission applications. Full article