Search Results (269)

The transportation of prefabricated components is challenged by the particularity of large cargo transport and urban road conditions, restrictions on parking, height, and weight. To address these challenges and to promote low-carbon logistics, this paper investigates the transportation of prefabricated components by leveraging separable fleets of trucks and trailers. Focusing on real-world constraints, this paper formulates the capacitated truck and trailer routing problem with time windows (CTTRPTW) incorporating carbon emissions, and designs a dynamic adaptive hybrid algorithm combining simulated annealing with tabu search (DASA-TS) to solve this model. The efficiency and robustness of the methodology are validated through two computational experiments. The results indicate that the DASA-TS consistently demonstrates excellent performance across all evaluations, with significant reductions in both transportation costs and carbon emissions costs for prefabricated components, particularly in large-scale computational instances. This study contributes to promoting the optimization of low-carbon transport for prefabricated components, offering guidance for routing design involving complex and large cargo, and supporting the sustainable development of urban logistics. Full article

The fifth wheel of the semi-trailer tractor is a key component connecting the tractor and the semi-trailer. During operation, the fifth wheel experiences frequent irregular and repetitive loading conditions. This leads to a decline in its durability and fatigue life, which can significantly impact the efficiency of cargo transport. The lightweight design enhances both the transport efficiency and fuel economy of the semi-trailer tractor. In this research, to achieve weight reduction while maintaining the wear-resistant failure protection performance in semi-trailer tractors, we selected a new material—special steel for saddles (SD600). Its stress-strain and fatigue life were analyzed under static compression, uphill lifting, and steering rollover conditions. These findings confirm the necessity of implementing lightweighting measures. Using a multi-objective genetic algorithm, we established an optimization model aimed at balancing weight reduction and fatigue life enhancement. As a result, the optimized fifth wheel achieved a 24.11% reduction in mass, while its fatigue life increased by 15 times, thus realizing the synergistic optimization of weight and fatigue life. We proposed a prediction model combining a random forest algorithm with an optimized back propagation (BP) neural network. Compared to the traditional BP approach, this model improved the mean absolute percentage error (MAPE) by 47.62%. Quadratic optimization was conducted based on the optimal design option set, using data analysis to determine the range of values of each variable under specific constraints and to verify the stress-strain and fatigue life for very small values in the range. Full article

In pursuit of sustainable development, worldwide adoption of hydrogen fuel cell vehicles (HFCVs) is growing to cut carbon emissions in the transportation sector. The construction of hydrogen refueling stations (HRSs) is the key to popularizing HFCVs. The popularity of HRSs is hindered by cost, site selection, and user expectations. Selecting mature gas stations with large passenger flow to expand HRSs can improve the accuracy of the hydrogen refueling network. Reducing the range anxiety of HFCV users to improve the path coverage of HFCVs is a favorable way to expand the hydrogen vehicle industry chain. Therefore, this study proposes a bi-level programming model, which considers hydrogen source (HS), hydrogen delivery mode (HDM), initial remaining range, range anxiety, and other factors. The upper-level model is designed to optimize economic costs, including the total chain cost of the HRS. The lower level aims to optimize the range anxiety of HFCV users and more accurately reflect their autonomy by controlling the maximum remaining range of the vehicle. Finally, the expressway in the Liaoning Province of China is taken as an example to verify that the optimization model had the advantages of low hydrogen cost and minimal range anxiety. The cost analysis of several HSs and HDMs was discussed from the perspective of the best site selected, and it was found that the Anshan HS using coal to produce hydrogen and the long tube trailer can provide lower hydrogen cost for the HRS. This method is generalizable to other regions or all types of HFCVs. Full article

This study presents a techno-economic analysis of hydrogen transportation via liquid organic hydrogen carriers by road, comparing this option with compressed hydrogen (350 bar) and liquefied hydrogen. The analysis includes the simulation of hydrogenation and dehydrogenation reactors for the dibenzyltoluene/perhydro-dibenzyltoluene system using ASPEN Plus, along with a cost assessment of compression, liquefaction, and trucking. A sensitivity analysis is also carried out, evaluating hydrogen transport at varying daily demand levels (1, 2, and 4 t/d) and transport distances (50, 150, and 300 km), with varying electricity prices and capital expenditures for hydrogenation and dehydrogenation units. Results indicate that compressed hydrogen is the most cost-effective solution for short distances up to 150 km, with a levelized cost of transported hydrogen ranging from 1.10 to 1.61 EUR/kg. However, LOHC technology becomes more competitive at longer distances, with LCOTH values between 1.49 and 1.90 EUR/kg at 300 km across all demand levels. Liquefied hydrogen remains the least competitive option, reaching costs up to 5.35 EUR/kg, although it requires fewer annual trips due to higher trailer capacity. Notably, at 150 km, LOHC transport becomes more cost-effective than compressed hydrogen when electricity prices exceed 0.22 EUR/kWh or when the capital costs for hydrogenation and dehydrogenation units are minimized. From an environmental perspective, switching from compressed to liquid hydrogen carriers significantly reduces CO₂ emissions—by 56% for LOHCs and 78% for liquid hydrogen—highlighting the potential of these technologies to support the decarbonization of hydrogen logistics. Full article

Agricultural tractors are equipped with air braking systems to supply and control the braking systems of towed vehicles. This system’s functional and operational characteristics significantly impact the compatibility and speed of the braking system of the tractor–trailer combination and are therefore checked during approval tests. This paper presents a test methodology and a description of the instrumentation and apparatus used to test the air braking systems of tractors under stationary conditions, as required by EU Regulation 2015/68. Sample test results of the trailer air supply system are included, such as checking the system for leaks, checking the pressure at the coupling heads, checking the compressor flow rate and air reservoir capacity, and checking the response time of the tractor control line. Approval authorities and tractor manufacturers can use the work results for quality control or product qualification tests. Full article

Crowdsourced manufacturing, which has emerged as a pivotal paradigm in the era of Industry 4.0, redefines traditional production models by leveraging decentralized decision-making and collaborative networks. This paper reviews the evolution of the open business model in the manufacturing sector and examines fundamental issues toward a holistic framework of crowdsourced manufacturing. Crowdsourced manufacturing is enacted through a full product fulfillment value chain encompassing value capturing, creation, and delivery through cooperation among various manufacturer crowds, open innovators, and platforms. The workflow of crowdsourced manufacturing involves these decision agents working collaboratively to achieve a synergy of networked information and material flows. An industrial example of tank trailer crowdsourced manufacturing is presented to illustrate the key concepts and clarify the primary technical issues of crowdsourced manufacturing. Full article

This study addresses a specialized variant of the full-truckload delivery problem inspired by a Turkish logistics firm that operates in the liquid transportation sector. An exact algorithm is proposed for the relevant problem, to which no exact approach has been applied before. Multiple customer and trailer types, as well as washing operations, are introduced simultaneously during the exact solution process, bringing new aspects to the exact algorithm approach among full-truckload systems in the literature. The objective is to minimize transportation costs while addressing constraints related to multiple time windows, trailer types, customer types, product types, a heterogeneous fleet with limited capacity, multiple departure points, and various actions such as loading, unloading, and washing. Additionally, the elimination or reduction of waiting times is provided along transportation routes. In order to achieve optimal solutions, an exact algorithm based on the column generation method is proposed. A route-based insertion algorithm is also employed for initial routes/columns. Regarding the acquisition of integral solutions in the exact algorithm, both dynamic and static sets of valid inequalities are incorporated. A label-setting algorithm is used to generate columns within the exact algorithm by being accelerated through bi-directional search, ng-route relaxation, subproblem selection, and heuristic column generation. Due to the problem-dependent structure of the column generation method and acceleration techniques, a tailored version of them is included in the solution process. Performance analysis, which was conducted using artificial input sets based on the real-life operations of the logistics firm, demonstrates that optimality gaps of less than 1% can be attained within reasonable times even for large-scale instances relevant to the industry, such as 120 customers, 8 product and 8 trailer types, 4 daily time windows, and 40 departure points. Full article

Path planning for intelligent semi-trailers encounters numerous challenges in complex traffic conditions. Serious consequences, such as vehicle rollover, may occur when the traffic conditions change. Therefore, it is vital to consider both the surrounding dynamic traffic conditions and the vehicle’s roll stability during the lane-changing process of intelligent semi-trailers. We propose an innovative path-planning method tailored for intelligent semi-trailers. This path-planning method is designed for semi-trailers on straight-road alignments. Firstly, we employ a fuzzy inference system to process information about surrounding traffic, make lane-changing decisions, and determine the starting point. Secondly, the lane-changing path is generated using a B-spline curve. Subsequently, we apply a particle swarm optimization algorithm to enhance the B-spline curve. Thirdly, we utilize a Transformer model to analyze the nonlinear relationships among information about surrounding traffic, vehicle information, and the roll stability of the intelligent semi-trailer. We establish the roll stability boundary for the vehicle. Finally, we design a multi-objective cost function to select the optimal path. The simulation results demonstrate that the proposed method dynamically adapts the planned path to variations in driving parameters, ensuring trackability while reducing the steering angle, lateral acceleration, and yaw rate. This approach meets the roll stability requirements of intelligent semi-trailers, significantly enhances their stability during lane changing, and provides robust support for safe and efficient operation. Full article

When a railway train runs along a curved track with braking, the dynamic behaviors of the vehicle are extremely complex and difficult to accurately reveal due to the coupling effects between the wheel–rail interactions and the disc–pad frictions. Therefore, a rigid–flexible coupled trailer car dynamics model of a railway train is established. In this model, the brake systems and vehicle system are dynamically coupled via the frictions within the braking interface, wheel–rail relationships and suspension systems. Furthermore, the effectiveness of the established model is validated by a comparison with the field test data. Based on this, the dynamic response characteristics of vehicle under curve and straight braking conditions are analyzed and compared, and the influence of the curve geometric parameters on vehicle vibration and operation safety is explored. The results show that braking on a curve track directly affects the vibration characteristics of the vehicle and reduces its operation safety. When the vehicle is braking on a curve track, the lateral vibration of the bogie frame significantly increases compared to the vehicle braking on a straight track, and the vibration intensifies as the curve radius decreases. When the curved track maintains equilibrium superelevation, the differences in primary suspension force, wheel–rail vertical force, and wheel axle lateral force between the inner and outer sides of the first and second wheelsets are relatively minor under both straight and curved braking conditions. Additionally, under these circumstances, the derailment coefficient is minimized. However, when the curve radius is 7000 m, with a superelevation of 40 mm, the maximum dynamic wheel load reduction rate of the inner wheel of the second wheelset is 0.54, which reaches 90% of the allowable limit value of 0.6 for the safety index, and impacts the vehicle running safety. Therefore, it is necessary to focus on the operation safety of railway trains when braking on curved tracks. Full article

Dump truck safety recommendations have been implemented by companies, but a comprehensive study of risk factors associated with dump truck injuries and fatalities has not been performed. Published research specifically focusing on dump truck injuries is limited. The purpose of this descriptive study was to characterize risk factors associated with dump truck-related inspection cases reported by the OSHA in the United States. Dump truck inspections during 2016–2020 were obtained from the online OSHA IMIS database. Pearson’s chi-square test and logistic regression were performed. An intraclass correlation coefficient (ICC) using PROC MIXED and a generalized linear mixed model was calculated on 122 closed dump truck-related inspection cases. One half of dump truck worker fatalities resulted in a serious OSHA violation, whereas three quarters of nonfatal dump truck worker injuries resulted in an ‘other’ or no OSHA violation; 22% of fatalities involved the dump truck backing up. A nonfatal injury narrative often involved the words ‘finger’, ‘tailgate’, and ‘bed’, whereas the words ‘trailer’, ‘asphalt’, ‘load’, and ‘loader’ were mentioned more often in fatalities. A fatal dump truck injury was three times more likely to be associated with a serious OSHA violation compared to a nonfatal dump truck injury. Industries should provide initial and refresher worker safety training to dump truck drivers and other employees who work within the dump truck hazard zone, particularly employees who utilize dump trucks for working with asphalt or around power lines, and employees who repair dump trucks. Full article

Background/Objectives: To investigate the value of intestinal fatty acid-binding protein (I-FABP), D-Lactate, interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-1 receptor antagonist (IL-1Ra), tumor necrosis factor-alpha (TNF-alpha), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), electrolytes and creatinine in athletes with lower gastrointestinal symptoms in a cohort of ultra-trailers. Methods: This is a prospective study set in the ultra-trail of Puy Mary Aurillac, a 105 km race. Athletes included were given two questionnaires to collect demographic data and clinical signs related to the race. Blood samples were also collected before and 1 h after the race. Biomarker results were interpreted according to the occurrence of exercise-induced lower gastrointestinal symptoms, and whether the race was completed or forfeited. Results: Of the 76 runners included, 35 (45.5%) presented lower gastrointestinal symptoms. Runners that presented these symptoms had significantly higher IL-10 concentrations (8.7 pg/mL (interquartile range (IQR): 4.2–1.6)) when compared to runners without symptoms (4.8 pg/mL (IQR: 2.4–9)) (p = 0.01). The pre/post-race amplitude of IL-1Ra variation was greater in the group of runners with lower gastrointestinal symptoms (median: +231% (IQR: 169–551)) compared to runners without symptoms (median: +172% (IQR: 91–393)) (p = 0.04). Finally, the 13 (16.9%) runners who forfeited the race displayed lower AST (p < 0.001), LDH (p = 0.002) and IL-6 (p = 0.002) concentrations, compared to runners who finished the race. These lower concentrations were independent from running time. Conclusions: IL-10 and IL-1Ra could be associated with the occurrence of lower gastrointestinal symptoms. Full article

As part of improving road safety around trucks, a solution was proposed to reduce the swept path width of a moving tractor–semi-trailer. This article presents a mathematical analysis of the movement of a tractor unit with a traditional semi-trailer with fixed axles and steered wheels. A simulation analysis of both presented vehicles was carried out. The core of the algorithm controlling the steering angle of the semi-trailer wheels is presented. The influence of controlling the semi-trailer’s swivel wheels on the swept path width of a tractor–trailer with a semi-trailer equipped with swivel wheels is discussed. The assumptions for building the control algorithm are presented. The article presents the advantages of the solution used along with the control algorithm. Measurable benefits resulting from the use of the presented solution are presented, such as increasing cargo space, reducing cargo transport costs, and reducing aerodynamic resistance and fuel consumption. It is worth emphasizing that reducing fuel consumption is very important because it reduces the emission of harmful exhaust gases into the atmosphere. The swept path width is important especially in the case of vehicles moving in a limited area, for example in the parking lots of transhipment and logistics centers, between urban buildings. Vehicles admitted to traffic meet the minimum conditions imposed by homologation regulations, but reducing the swept path width allows for improving the operational properties of the tractor–semi-trailer. The use of the proposed control algorithm to control the turn of the semi-trailer’s steered wheels brings tangible benefits both in improving road safety and in reducing the emission of harmful substances into the environment. Full article

The transport of freshly post-harvested fruit to its collection point is mainly achieved using trailers over uneven terrain, which generates impacts and vibrations that negatively affect the quality of the fruit. Although some solutions to mitigate these effects have been proposed in previous studies, none of them are applied directly to the source of the problem, i.e., the transport boxes. In this context, metamaterial sheets inspired by the design of quasi-zero stiffness isolators (QZSs) open up the possibility of exploring ways of vibration isolation thanks to their associated nonlinear characteristics. In this work, ABS sheets with different internal geometries were manufactured and compared as possible bottoms of transport boxes. Vibration reduction not only protects the physical integrity of the fruit, avoiding visible damage such as bumps or bruises, but also preserves its chemical properties, such as texture and freshness, which directly impacts its shelf life and presentation for sale. The design variables analyzed for these geometries included the number of ribs, their thickness and their angle of inclination. In these specimens, their behavior to impact-type forces and their experimental dynamic behavior were studied using an electromagnetic shaker against a sinusoidal signal and against the uniaxial vibration recorded at the base of a trailer in a real rural route. The results showed that the specimens with a rib angle of 30° and a thickness of 0.4 mm showed the best impact performance and a higher amplification of vibration transmissibility in the steady state. In the presence of the signal recorded on the route, transmissibility reduction percentages between 13% and 19% were obtained in the principal acceleration impact. Full article

The design and industrial innovation of intelligent agricultural machinery and equipment for saline alkali land are important means for comprehensive management and capacity improvement of saline alkali land. The autonomous and unmanned agricultural tractor is the inevitable trend of the development of intelligent machinery and equipment in saline alkali land. As an underactuated system with non-holonomic constraints, the independent trajectory planning and lateral stability control of the tractor-trailer system (TTS) face challenges in saline alkali land. In this study, based on the nonlinear underactuation characteristics of the TTS and the law of passive trailer steering, a dual-trajectory collaborative control model was designed. By solving the TTS kinematic/dynamic state space, a nonlinear leading system that can generate the reference pose of a tractor-trailer was constructed. Based on the intrinsic property of the lateral deviation of the TTS, a collaborative trajectory prediction algorithm that satisfies the time domain and system constraints is proposed. Combining the dual-trajectory independent offset and lateral stability parameter of the TTS, an energy function optimization control parameter was constructed to balance the system trajectory tracking performance and lateral control stability. The experimental results showed good agreement between the predicted trailer trajectory and the collaborative control trajectory, with an average lateral error not exceeding 0.1 m and an average course angle error not exceeding 0.054 rad. This ensures that the dynamic controller designed around the tractor-trailer underactuation system can guarantee the smoothness of the trailer trajectory and the controlling stability of the tractor in saline alkali land. Full article

The article compares the properties of coatings (cataphoretic, hot-dip zinc, and thermo-diffusion zinc) applied to steel components used in the automotive industry. The research focused on the analysis of corrosion resistance, hardness measurements, and tribological properties conducted on steel guides used in trailer and truck body structures as well as fasteners (M12 × 40 bolts). The base surfaces were cleaned chemically. Corrosion resistance was tested in a salt chamber, while coating thickness was measured using the magnetic induction method. Coating hardness (HV 0.02) was assessed with a microhardness tester, and tribological properties were tested under dry friction conditions. The results showed that the zinc coatings demonstrated corrosion resistance far superior to paint coatings. Full article