Search Results (154)

As a core component of automated logistics systems, delivery robots hold significant application value in the field of unmanned delivery. This research addresses the robot path planning problem, aiming to enhance delivery efficiency and reduce operational costs through systematic improvements to the RIME optimization algorithm. Through in-depth analysis, we identified several major drawbacks in the standard RIME algorithm for path planning: insufficient global exploration capability in the initial stages, a lack of diversity in the hard RIME search mechanism, and oscillatory phenomena in soft RIME step size adjustment. These issues often lead to undesirable phenomena in path planning, such as local optima traps, path redundancy, or unsmooth trajectories. To address these limitations, this study proposes the Multi-Strategy Controlled Rime Algorithm (MSRIME), whose innovation primarily manifests in three aspects: first, it constructs a multi-strategy collaborative optimization framework, utilizing an infinite folding Fuch chaotic map for intelligent population initialization to significantly enhance the diversity of solutions; second, it designs a cooperative mechanism between a controlled elite strategy and an adaptive search strategy that, through a dynamic control factor, autonomously adjusts the strategy activation probability and adaptation rate, expanding the search space while ensuring algorithmic convergence efficiency; and finally, it introduces a cosine annealing strategy to improve the step size adjustment mechanism, reducing parameter sensitivity and effectively preventing path distortions caused by abrupt step size changes. During the algorithm validation phase, comparative tests were conducted between two groups of algorithms, demonstrating their significant advantages in optimization capability, convergence speed, and stability. Further experimental analysis confirmed that the algorithm’s multi-strategy framework effectively suppresses the impact of coordinate and dimensional differences on path quality during iteration, making it more suitable for delivery robot path planning scenarios. Ultimately, path planning experimental results across various Building Coverage Rate (BCR) maps and diverse application scenarios show that MSRIME exhibits superior performance in key indicators such as path length, running time, and smoothness, providing novel technical insights and practical solutions for the interdisciplinary research between intelligent logistics and computer science. Full article

The bond interface is the weakest part of the repair system, and its performance is a key factor impacting the repair effectiveness of damaged concrete constructions. However, the research on the damage law and the mechanism of repair of the bonded interface in the cold region marine environment is not in-depth. In this study, the influence of polyvinyl alcohol (PVA) fibers and crystalline admixtures (CAs) on the mechanical properties and volumetric deformation performance of cementitious repair materials was researched. Furthermore, the deterioration patterns of the bond strength and chloride ion diffusion characteristics of the repair interface under the coupling of seawater-freeze-thaw cycles were investigated. Combined with the composition, micro-morphology, and micro-hardness of hydration products before and after erosion, the damage mechanism of the repaired bonding interface was revealed. The results indicate that the synergistic use of PVA fibers and CAs can significantly improve the compressive strength, bond strength and volume stability of the repair materials. The compressive strength and 40° shear strength of S0.6CA at 28 d were 101.7 MPa and 45.95 MPa, respectively. Under the seawater-freeze-thaw cycle action, the relationship between the contents of free and bound chloride ions in the bonded interface can be better fitted by the Langmuir equation. The deterioration process of the bonding interface and the penetration rate of chloride ions can be effectively delayed by PVA fiber and CAs. After 700 seawater-freeze-thaw cycles, the loss rates of bond strength and chloride diffusion coefficient of S0.6CA were reduced by 26.34% and 52.5%, respectively, compared with S0. Full article

As mainstream solvers for black-box optimization problems, evolutionary computation (EC) methods struggle with finding desired optima of lower attractiveness. Researchers have designed benchmark problems for simulating this scenario and proposed a large number of niching methods for solving those problems. However, factors causing the difference in attractiveness between local optima are often coupled in existing benchmark problems, which makes it hard to clarify the primary contributors. In addition, niching methods are carried out using a combination of several niching techniques and reproduction operators, which enhances the difficulty of identifying the essential effects of different niching techniques. To obtain an in-depth understanding of the above issue, thus offering actionable insights for optimization tasks challenged by the multimodality, this paper uses continuous optimization as an entry point and focuses on analyzing differential behaviors of EC methods across different basins of attraction. Specifically, we quantitatively investigate the independent impacts of three features of basins of attraction via corresponding benchmark scenarios generated by Free Peaks. The results show that the convergence biases induced by the difference in distribution only occur in EC methods with less uniform reproduction operators. On the other hand, convergence biases induced by differences in size and average fitness, both of which equate to the difference in size of superior region, pose a challenge to any EC method driven by objective functions. As niching methods limit survivor selection to specified neighborhoods to mitigate the latter biases, we abstract five niching techniques from these methods by their definitions of neighborhood for restricted competition, thus identifying key parameters that govern their efficacy. Experiments confirm these parameters’ critical roles in reducing convergence biases. Full article

In response to the increasing frequency of urban rainstorms, this study focuses on investigating the friction coefficient related to pedestrian instability under urban road flooding conditions. The objective is to conduct an in-depth analysis of the friction coefficient between pedestrians and the ground in actual flood scenarios and its variations, providing practical data to support future pedestrian safety assessments under flood conditions. Wet friction coefficient experiments were conducted under waterlogged conditions, with real human subjects tested across various operational scenarios. A buoyancy calculation formula was introduced to explore the impact of pressure changes caused by buoyancy on the human body in water, influencing the friction coefficient. An exponential relationship between pressure and the friction coefficient was established. Furthermore, by considering factors such as outsole hardness, ground type, and pressure variations with water depth, a dynamic method for selecting the friction coefficient was proposed, offering a scientific basis for determining friction coefficient thresholds associated with pedestrian instability risks. Experimental results indicate that, in the combination of hydrophilic materials with experimental asphalt and cement pavements, the friction coefficient under waterlogged conditions is generally higher than under dry conditions. However, as pressure increases, the friction coefficient of rubber materials decreases. This study concludes that the selection of the friction coefficient in pedestrian instability analysis should be treated as a dynamic process, and relying on a fixed friction coefficient for force analysis of pedestrian instability may lead to significant inaccuracies. Full article

CCS/CCUS is considered vital for global climate mitigation, especially in decarbonizing hard-to-abate sectors like upstream oil and gas. In Indonesia, however, its deployment remains limited due to fragmented stakeholder views and lack of integrated policy support. This study explores multi-stakeholder perspectives, including government, academia, business, finance, media, and civil society, on the role and feasibility of CCS/CCUS in achieving the country’s net zero emissions (NZE) target. Using a mixed-method approach, we conducted structured surveys (n = 39) and in-depth interviews (n = 34). Findings reveal broad support for CCS/CCUS but highlight ongoing concerns about economic viability, regulatory uncertainty, and environmental risks. Stakeholders emphasize the need for stronger government incentives and cross-border financing mechanisms. The study underscores the importance of inclusive policymaking, enhanced fiscal support, and integration of CCS/CCUS into Indonesia’s carbon economic value framework to ensure a more participatory and sustainable climate policy pathway. Full article

Surface roughness plays a vital role in determining surface integrity and function. Surface irregularities or reduced quality near the surface can contribute to material failure. Surface roughness is considered a crucial factor in estimating the fatigue life of structures welded by FSW. This study attempts to provide a deeper understanding of the nature of the surface formation and roughness of aluminum joints during FSW processes. In order to form more efficient joints, the frictional temperature generated was monitored until reaching 450 °C, where the transverse movement of the tool and the joint welding began. Hardness and tensile tests showed that the formed joints were good, which paved the way for more reliable surface roughness measurements. The surface roughness of the weld joint was measured along the weld line at three symmetrical levels using welding parameters that included a rotational speed of 1250 rpm, a welding speed of 71 mm/min, and a tilt angle of 1.5°. The average hardness in the stir zone was measured at 64 HV, compared to 50 HV in the base material, indicating a strengthening effect induced by the welding process. In terms of tensile strength, the FSW joint exhibited a maximum force of 2.759 kN. Average roughness (Rz), arithmetic center roughness (Ra), and maximum peak-to-valley height (Rt) were measured. The results showed that along the weld line and at all levels, the roughness coefficients (Rz, Ra, and Rt) gradually increased from the beginning of the weld line to its end. The roughness Rz varies from start to finish, ranging between 9.84 μm and 16.87 μm on the RS and 8.77 μm and 13.98 μm on the AS, leveling off slightly toward the end as the heat input stabilizes. The obtained surface roughness and mechanical properties can give an in-depth understanding of the joint surface forming and increase the ability to overcome cracks and defects. Consequently, this approach, using adaptive thresholding image processing coupled with grayscale histogram analysis, yielded significant understanding of the FSW joint’s surface texture. Full article

The instability of wellbore in hard and brittle shale formations is a key bottleneck constraining the safety and efficiency of drilling engineering. Traditional studies focused on drilling fluid density, particle plugging, and chemical inhibition; however, there is a lack of in-depth analysis on the precise control mechanism of wellbore stability by the rheological properties of drilling fluids. Specifically, while traditional methods are limited in addressing mechanical instability in hard brittle shales with pre-existing micro-fractures, rheological control offers a potential solution by influencing pressure transmission within these fractures. To address this research gap, this study aims to reveal the influence of drilling fluid rheological parameters (specifically viscosity and yield point) on the pressure transmission behavior of the micro-fracture network in hard and brittle shale and to clarify the intrinsic mechanism by which rheological properties stabilize the wellbore. Micro-structure analysis confirmed interconnected micro-fractures (0.5–30 μm). A micro-fracture flow model and simulations evaluated viscosity and yield point effects on pressure transmission. A higher viscosity significantly increased the pressure drop (ΔP) near the wellbore, with limited transmission distance effects. The yield point was minimal. The study reveals that optimizing rheology, particularly increasing viscosity, can suppress pore pressure, reduce collapse pressure, and improve stability. The findings support rheological parameter optimization for safer, economical drilling. In terms of rheological parameter optimization design, this study suggests emphasizing the increase in drilling fluid viscosity to effectively manage wellbore stability in hard brittle shale formations. Full article

Particle-reinforced Al-based matrix composites have great potential for application in aerospace, automotive manufacturing, and defense due to their high strength, hardness, and excellent wear and corrosion resistance. However, the presence of particles increases the processing difficulty, making it a typical difficult-to-machine material. In recent years, ultrasonic vibration-assisted machining has been quite popular in manufacturing this kind of material. This paper reviews the research advancements in ultrasonic vibration-assisted machining of particle-reinforced Al-based matrix composites, providing a comprehensive analysis of the effects of introducing an ultrasonic energy field on tool wear, chip morphology, cutting force, cutting temperature, and surface integrity. Ultrasonic vibration periodically alters the contact state between the tool and the workpiece, effectively reducing the tool wear rate and extending the tool life. Meanwhile, ultrasonic vibration facilitates the fracture and ejection of chips, enhancing chip morphology and reducing energy consumption during the cutting process. Additionally, ultrasonic vibration significantly decreases cutting force and cutting temperature, contributing to the stability of the cutting process and improving processing efficiency. Regarding surface integrity, ultrasonic vibration-assisted machining refines the machined surface’s microstructure, reducing surface defects and residual stress, thereby significantly enhancing the machining quality. In the future, we will conduct in-depth research on the effects of ultrasonic energy on material properties in terms of softening effect, thermal effect, and stress superposition, further revealing the mechanism of ultrasonic vibration-assisted processing of particle-reinforced aluminum-based composite materials. Full article

The laser cladding technique can be adapted to fabricate composite coatings on the surface of the metal substrate, which not only effectively improves the surface properties of materials, but also greatly expands their application range. Metal carbides exhibit extremely high hardness, melting point, and outstanding chemical stability. The hardness of carbides is much higher than that of general metal materials. Therefore, various metal carbides serve as reinforcing agents for enhancing the overall performance of metal-based coatings. To date, there is no special review about metal carbide-reinforced laser cladding coatings. In view of the outstanding performance and wide application of metal carbides in laser cladding coatings, herein, recent advances in various metal carbide-reinforced metal coatings are highlighted. According to the type of metal carbides, the whole review is classified into five sections: WC-reinforced coatings, TiC-reinforced coatings, NbC-reinforced coatings, Ti_n+1AlC_n (MAX) reinforced coatings, and Cr₃C₂, TaC-reinforced coatings. The preparation method, microstructure feature, and application performance of various carbide-reinforced composite coatings are summarized. At last, some prospects are put forward on the current issues and future development directions, aiming to provide comprehensive and in-depth references for the research and application in the field of composite coatings. Full article

Nanocrystalline diamond (NCD) is regarded as a highly promising composite engineering material owing to its superior mechanical properties. Surface texturing significantly enhances the surface performance of NCD. Given the unique inherent combination of hardness and brittleness in NCD, laser ablation emerges as a critical method for fabricating surface microstructures. However, the research on laser-induced surface texturing of NCD remains limited. This study experimentally investigated the characteristics of nanosecond laser-ablation-induced graphitization in NCD and provided an in-depth analysis of the laser ablation mechanism, aiming to guide the optimization of NCD surface microtexture manufacturing. Specifically, we conducted systematic nanosecond pulse laser ablation experiments on NCD samples and utilized Raman spectroscopy to qualitatively characterize the graphitization within microgrooves and across the entire ablated surface. The effects of the laser scanning speed, power, defocus level, and scanning interval on the graphitization extent and morphological characteristics were systematically investigated, identifying the single-factor optimal parameter set for maximizing graphitization. Through single-factor experimental analysis, the findings of this study provide foundational data for subsequent multivariate-coupled optimization and offer theoretical support for enhancing the surface properties of NCD through microtexturing via laser ablation. Full article

Nanostructured materials have garnered significant attention for their unique properties, such as the high surface area and enhanced reactivity, making them ideal for electrocatalysis. Among these, perovskite oxides, with compositional and structural flexibility, stand out for their remarkable catalytic performance in energy conversion and storage technologies. Their diverse composition and tunable electronic structures make them promising candidates for key electrochemical reactions, including the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and carbon dioxide reduction (CO₂RR). Nanostructured perovskites offer advantages such as high intrinsic activity and enhanced mass/charge transport, which are crucial for improving electrocatalytic performance. In view of the rapid development of nanostructured perovskites over past few decades, this review aims to provide a detailed evaluation of their synthesis methods, including the templating (soft, hard, colloidal), hydrothermal treatments, electrospinning, and deposition approaches. In addition, in-depth evaluations of the fundamentals, synthetic strategies, and applications of nanostructured perovskite oxides for OER, HER, and CO₂RR are highlighted. While progress has been made, further research is needed to expand the synthetic methods to create more complex perovskite structures and improve the mass-specific activity and stability. This review offers insights into the potential of nanostructured perovskite oxides in electrocatalysis and provides potential perspectives for the ongoing research endeavor on the nanostructural engineering of perovskites. Full article

This article is an interdisciplinary study. The authors (a canon lawyer and a biblical theologian) endeavour to examine the text of the Book of Deuteronomy 24:1 through both canonical and exegetical lenses. They look at whether and to what extent it is aligned with the contemporary Catholic teaching on the permanence and indissolubility of marriage. They frame the research problem through a series of questions: Is the analysed text contrary to the Catholic Church’s position on the inadmissibility of divorce? Does it imply consent to divorce? Or does it permit marital separation but solely under specific conditions? First, the authors discuss the Catholic teaching on the permanence and indissolubility of marriage. They highlight a distinction between the two terms. They seek to expose the process of evolution of the institution of marriage from the Creation, i.e., God’s original intention in relation to marriage, through the Old Testament period of “hardness of heart”, i.e., from the original sin to the time of Jesus, to the third stage since Jesus, who restored the original order destroyed by sin and elevated the conjugal bond of two baptized people to the dignity of a sacrament. The authors then examine the concept of marital separation. By its very nature, it does not sever the marital bond. The authors explain the legal grounds for separation, among them adultery and failure to maintain marital fidelity. Next, they conduct an in-depth semantic analysis of the studied text and discuss divorce proceedings in the light of Deuteronomy 24:1. They close the discussion with conclusions. Due to the interdisciplinary nature of the work, the authors relied on the literature from the domains of biblical studies and canon law. Full article

This review explores the current state of public key cryptography based on idempotent semirings, with an emphasis on tropical semirings. It examines key hard problems, such as the tropical discrete logarithm problem, semidirect tropical product problem, the factorization of tropical polynomials, and the matrix power function, that underpin the security of these protocols. Given the significant number of compromised protocols based on tropical semirings, most of which are variations of the Stickel protocol, we present three algorithms and classify schemes of this type. The analysis is further illustrated with a figure that maps the relationships between tropical Stickel’s-like protocols and the attacks targeting them. Additionally, the review provides an in-depth exploration of the vulnerabilities that have led to many tropical semiring-based cryptosystems being compromised. To address these challenges, the review highlights promising alternative approaches, including non-tropical idempotent platforms and non-idempotent options, such as supertropical semirings, which offer potential solutions to overcome known limitations. Furthermore, a discussion on the interplay between tropical cryptography and post-quantum cryptography is presented, raising the following question: what is the future of tropical cryptography? Full article

With the increasing complexity of engineering environments in tunnel construction, the vibrations generated by shield tunneling in hard rock strata pose significant challenges to the operation and maintenance of adjacent tunnels. This study investigates the vibration characteristics induced by shield tunneling and provides an in-depth analysis of the propagation behavior of these vibrations within tunnel segments and surrounding soil layers. Through a combination of theoretical derivations, on-site monitoring, and numerical simulations, the research examines the distribution of vibration energy and its attenuation patterns with increasing propagation distance. The findings reveal that vibration energy is primarily concentrated in the low-frequency range (3–4 Hz) and follows an exponential decay trend as distance increases. Furthermore, the vibration response of neighboring tunnels is heavily influenced by the construction vibration source, with rapid energy attenuation observed over short distances. Numerical simulations conducted using PFC3D6.0 (Particle Flow Code) software validate the theoretical model and emphasize the critical roles of soil-damping properties and tunnel segment material characteristics in vibration attenuation. This study offers a robust theoretical framework and valuable data to support the control of tunnel vibrations and the optimization of construction practices. Full article

Aluminum and its alloys are widely used in the busbar structures of electrolytic aluminum production. However, they are prone to corrosion and wear damage during use, leading to a decline in current-transmission efficiency and potentially causing safety issues. To repair damaged aluminum busbars, this paper explores the feasibility of using cold spraying technology for surface restoration. Using 6063 aluminum alloy as the substrate, AlZn/nickel-plated graphite composite coatings were applied through cold spraying. The effects of different nickel-plated graphite contents on the microstructure, mechanical properties, and corrosion resistance of the coatings were studied. Annealing treatments (200 °C, 300 °C, 400 °C) were further used to improve the coating’s density and performance. The results show that with an increase in the nickel-plated graphite content, the porosity of the coating gradually increases, while the coating’s density and bond strength improve. Additionally, the annealing treatment significantly enhanced the uniformity and hardness of the coating. Moreover, the cold-sprayed coatings exhibited excellent corrosion resistance, especially in the annealed coatings, which showed superior microstructural stability and lower corrosion current density. This study provides a new technological approach for the repair of aluminum busbars and offers an in-depth discussion on the application of cold spraying technology in the surface restoration of aluminum-based composite materials. Full article