Side-boss parallel channels can enhance reactant transport and water removal in proton exchange membrane fuel cells, but their local protrusions increase the forming difficulty of ultra-thin metallic bipolar plates. This study numerically investigates the single-step stamping formability of 0.1 mm SS304 bipolar plates using Dynaform. The effects of side-boss number, side-boss height, and punch speed were evaluated through thickness distribution, maximum thinning ratio, and forming-limit-diagram states. The results show that side-boss height is the dominant geometric factor. Increasing the height from 0 to 0.75 mm raises the maximum thinning ratio from 17.69% to 29.87% and shifts the critical deformation regions from the conventional channel bottom toward the side-boss roots, boss tops, transition fillets, and channel corners. The number of side-boss sets produces a non-monotonic thinning response, with maximum thinning ratios ranging from 19.54% to 27.76% for the modified configurations. Punch speeds of 200, 500, and 800 mm/s yield comparable thinning levels of 24.60%, 23.09%, and 23.16%, respectively, whereas the value increases to 26.30% at 1100 mm/s. Under the present forming conditions, these findings establish a quantitative relationship between side-boss geometry, material-flow restriction, and strain localization, and provide practical guidance for geometry selection and stamping-process design of metallic bipolar plates.

Dry gas reservoirs play a pivotal transitional role in meeting the net-zero target worldwide. Accurate modelling and simulation of this energy source require fast and reliable prediction of the gas compressibility factor (Z-factor). The experimental measurements of Z-factor are the most reliable source; however, they are expensive and time-consuming. This makes developing accurate predictive models essential. Traditional methods, such as empirical correlations and Equations of States (EoSs), often lack accuracy and computational efficiency. This study aims to address these limitations by leveraging the predictive power of machine learning (ML) techniques. Hence in this study three ML models of Artificial Neural Network (ANN), Group Method of Data Handling (GMDH), and Genetic Programming (GP) were developed. These models were trained on a comprehensive dataset comprising 1079 samples where pseudo-reduced pressure (Ppr) and pseudo-reduced temperature (Tpr) served as input and experimentally measured Z-factors as output. The performance of the developed ML models was benchmarked against two cubic EoSs of Peng-Robinson (PR) and van der Waals (vdW), and two semi-empirical correlations of Dranchuk-Abou-Kassem (DAK) and Hall and Yarborough (HY), and recent developed ML based models, using statistical metrics of Mean Squared Error (MSE), coefficient of determination (R2), and Average Absolute Relative Deviation Percentage (AARD%). The proposed ANN model reduces average prediction error by approximately 70% relative to the PR equation of state and by over 35% compared with the DAK correlation, while maintaining robust performance across the full Ppr and Tpr of dry gas systems. Additionally paired t-tests and Wilcoxon signed-rank tests performed on the ML results confirmed that the ANN model achieved statistically significant improvements over the other models. Moreover, two physical equations using the white-box models of GMDH and GP were proposed as a function of Ppr and Tpr for prediction of the dry gas Z-factor. The sensitivity analysis of the data shows that the Ppr has the highest positive effect of 88% on Z-factor while Tpr has a moderate effect of 12%. This study presents the first unified, statistically validated comparison of ANN, GMDH, and GP models for accurate and interpretable Z-factor prediction. The developed models can be used as an alternative tool to bridge the limitation of cubic EoSs and limited accuracy and applicability of empirical models.

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) have emerged as a promising clean energy-conversion technology owing to their simplified water management, enhanced tolerance to fuel impurities, and potential for high-grade waste-heat utilization. However, under high-temperature, phosphoric-acid-rich, and dynamically changing operating conditions, the durability of key materials and interfaces remains inadequate, while the degradation of core components—including the catalyst layer (CL), proton exchange membrane (PEM), gas diffusion layer (GDL), and bipolar plate (BP)—is not an isolated process but arises from the coupled evolution of phosphoric acid redistribution, catalyst/support deterioration, interfacial transport losses, and stack-level operating stresses, thereby severely restricting the large-scale deployment of HT-PEMFCs. This review systematically summarizes the degradation mechanisms of these key components and the latest mitigation strategies in material design and structural optimization. Based on the above analysis, the remaining challenges for HT-PEMFCs are clarified, and future directions are proposed toward more durable, standardized, and commercially viable systems.

ABSTRACT Proton exchange membrane fuel cells (PEMFCs) operating at high power density are often constrained by non‐uniform reactant distribution, local liquid water accumulation, and concentration polarization. To address insufficient under‐rib oxygen transport, weak‐reaction regions, and unstable water removal in conventional two‐pass serpentine flow fields, this study proposes a conjugate dual‐channel serpentine flow field incorporating local guide units for metallic bipolar plates. On each bipolar plate face, the reactant stream supplied through a common inlet is divided into two parallel serpentine branches, which are arranged in an in‐plane mirror‐symmetric configuration and subsequently recombine at a common outlet. The same geometry is independently employed on the anode and cathode sides, with the two flow fields arranged mirror‐symmetrically across the membrane electrode assembly. A three‐dimensional non‐isothermal multiphysics model is developed to investigate the mass transport, electrochemical behavior, and water‐management performance of the proposed configurations. Compared with the baseline two‐pass serpentine flow field, the designs incorporating guide units increase the oxygen uniformity index from 0.689 to 0.773–0.776, reduce the current‐density non‐uniformity index from 0.133 to 0.092–0.095, and increase the minimum current flux density in weak‐reaction regions to 6.27–9.95 times the baseline value. The wing‐shaped configuration provides the best overall balance among oxygen uniformity, current‐density uniformity, pressure‐drop penalty, and liquid water control. The U‐shaped configuration shows a greater tendency toward water retention, whereas the trapezoidal and Tesla‐valve‐shaped configurations incur larger pressure‐drop penalties. The results demonstrate that the local guide units improve active‐area utilization primarily by inducing transverse reactant transport, enhancing under‐rib oxygen supply, and mitigating weak‐reaction regions rather than merely increasing the local peak current density. The proposed structure combines enhanced mass transfer and improved water management with potential compatibility with single‐step stamping, providing a reference for metallic bipolar plate flow‐field design in high‐power‐density PEMFCs.

While Battery Electric Vehicles (BEVs) offer environmental benefits by reducing carbon emissions during use, their range remains limited compared to conventionally fuelled vehicles. This paper focuses on identifying factors that directly influence BEV range and explores strategies to mitigate range anxiety among potential users. Specifically, it reviews the impact of battery cell characteristics and vehicle lightweighting. Using the WLTP Class 3B drive cycle, energy consumption and Depth of Discharge (DoD) were evaluated across various battery capacities. Multiple Lithium-Ion battery models were simulated to analyse discharge behaviour, while vehicle mass composition was examined to assess the effectiveness of lightweighting in extending driving range. A lower initial State of Charge (SoC) and a standard discharge rate were used to estimate the remaining range, highlighting an approximate gain of up to 6 km at lower DoD levels. This work aims to accurately demonstrate how battery technology and structural weight impact energy consumption and usable range in BEVs. Current modelling approaches often overlook the relationship between driver discomfort and battery performance metrics. The main contribution is to address the gap by integrating Li-ion discharge modelling with vehicle dynamics to estimate range and compare cell characteristics. The ultimate goal is to support cost-effective strategies for increasing BEV usability, aligning them more closely with conventional vehicle expectations and enhancing journey flexibility.

A reasonable flow field structure plays a significant role in reducing the cost of fuel cells and improving their stability. To explore the effects and mechanisms of the arrangement of rectangular sub-channels and bosses in the flow field structure on fuel cell performance, a numerical simulation method was used to analyze the impacts of different arrangement patterns on fuel performance enhancement. The results show that: In the parallel flow field design, adding bosses in the front half can promote the efficient introduction of oxygen and effective drainage, while adding rectangular sub-channels in the rear half can enhance the exchange efficiency of oxygen and water. By optimizing the channel structure, the uniform distribution of liquid within the channels is promoted, local accumulation is reduced, and the system stability and drainage efficiency are enhanced, achieving efficient fluid management. Compared with the parallel flow field structure, this optimized design increases the power density of fuel cells by $\mathbf{1 3. 2 3 \%}$.

In general, an internal combustion engine vehicle is still the convention in personal and commercial transport, but due to its high use stage CO2 emission, a shift is occurring in propulsion methods, and the use of battery electric vehicles (BEV) will become the new norm. BEV’s curb weight is, in general, greater than that of a conventional fuelled vehicle (CFV) for equivalent classes. Consequently, it is questionable that the level of BEV’s energy consumption is acceptable. The aim of this paper is to compare the mass induced energy consumption of CFV and BEV. The expectation is that the comparative study of energy consumption between CFV and BEV will provide insight for proposing a strategy to determine the extent to which lightweighting can be introduced to a BEV. Encouragingly, less exhaustive energy consumption can help by reducing range anxiety by increasing BEV range, resolving one issue facing a BEV. With a typical road condition for hilly and flat roads, various drive cycles are also taken into consideration, and the energy consumption profiles for CFV and BEV can be determined. The vehicle model involved using the MATLAB/Simulink software underpinned by longitudinal vehicle dynamic methods. The idea is to determine the amount of lightweighting of various components of a BEV through an iterative process based on energy consumption profiles. As a function of mass reduction, for comparative energy expenditure, the results showed that a range of 28 to 36% reduction in BEV mass was achieved, which in turn can increase the driving range by 36.4 to 46.8%.

The preparation of amorphous alloys typically involves rapid solidification from a molten state. Since 1980, when Yermo and Koch first achieved the amorphization of alloys by mechanical alloying (MA), researchers worldwide have developed a strong interest in this technique, which allows for the amorphization of alloy components in a non-equilibrium state at room temperature without the need for a liquid phase. MA has been widely applied in the fabrication of both equilibrium and non-equilibrium materials over the past few decades, and it remains a crucial technique for the production of amorphous alloys. This review selectively summarizes research on MA-produced amorphous alloys reported over the past two decades. It explores key issues of MA amorphization from the perspectives of both the mechanism of amorphization and the design of amorphous compositions through MA. The first section primarily elucidates commonly used methods for designing amorphous compositions at present, while the second section expounds on the transformation mechanism of MA amorphization. The third section summarizes the influence of alloy element additions on its properties, and the fourth section mainly illustrates the contribution of computational advancements to the exploration of amorphous mechanisms and the design of amorphous compositions. Finally, prospects for the development trend of preparing amorphous alloys through MA are discussed.

Organic Rankine cycle (ORC) technology with attractive advantages can be effectively used for low temperature heat recovery. Due to the current research deficiencies and ORC system characteristics in ammonia synthesis manufacturing plant, the developed therm-economic optimization is established, considering the consumption of circulating water subsystem. According to the equilibrium of pay and gain exergy, the coefficient of exergy performance (COEP) of total system is proposed. The behaviors and detailed discussions of the electricity production cost (EPC), which consists of direct energy cost, primary non-energy cost, circulating water subsystem cost, and organic fluid cost, are examined. The exergy and economic comparison is conducted, and optimization is implemented for maximum COEP and minimum EPC. Furthermore, according to evaluation results, there are contradictions between equipment optimization and system optimization in certain operating conditions. Better system performance is achieved in specific evaporation temperature, lower condensation temperature and larger circulating water temperature rise. Under the optimal operation condition, the exergy efficiency of condenser and system is improved by 35.53% and 5.00%, the COEP increases by 1.65, and the EPC is reduced by 0.043 Yuan/kWh, respectively. The annual carbon dioxide emission reduction is developed to 3736.30 tons according to the international specification and the latest carbon dioxide emission factor of power generation in China. The improved therm-economic optimization method is of significance for the selection of optimization methods in practical projects.

Using phenolic resin（PF） modified epoxy resin（EP） as the matrix and doping silane-modified nano-Al 2 O 3 into it, the nano Al 2 O 3 -PF/EP composite coating was prepared. The composite coatings were characterized by testing techniques such as infrared spectroscopy（FTIR）, contact angle measurement and electrochemical impedance spectroscopy（EIS）. The results showed that the silane modified nano-Al 2 O 3 and PF reacted with EP, the permeability and crosslinking density of the coating cured by PF were improved. The corrosion resistance of nano Al 2 O 3 -PF/EP composite coating was better than that of EP coating and PF/EP coating, and the composite coating doped with nano-Al 2 O 3 mass fraction of 3% had the best corrosion resistance. The dispersion and stability between nano-Al 2 O 3 modified by silane and PF/EP were increased, and the coating becomed denser, which hindered the diffusion of corrosive medium, thus the corrosion resistance of composite coating was improved.

With the continuous development of internal combustion engine technology, the thermal efficiency of traditional energy vehicles has been difficult to improve, and the heat loss caused by high-temperature exhaust emissions is an important reason for the low thermal efficiency. To utilize the exhaust heat, the aim is to develop various spiral tube heat exchanger designs, namely, constant curvature heat exchanger with baffle and variable curvature heat exchanger. The design has been evaluated by referring to the performance evaluation coefficient (PEC); furthermore, the convection coefficient h has been taken into consideration as well. The idea is to perform numerical studies via computational fluid dynamics package and evaluate the performance of the spiral tube heat exchanger designs. PEC is the relationship between the heat exchange intensity of the heat exchanger and the flow resistance of the working fluid. The results show that the PEC evaluation index of the heat exchanger is the best when the spiral diameter of the heat exchange tube is 120 mm, and with the increase of the tube diameter and pitch, the overall performance of the heat exchanger decreases. The research on heat transfer enhancement of heat exchangers was carried out, and various spiral tube heat exchangers were designed based on the structure of spiral heat exchange tubes. The variable curvature heat exchanger has better overall performance than the baffle constant curvature heat exchanger. Compared to the single-variable curvature and the double-variable curvature, the maximum PEC difference of them does not exceed 0.01, and the double-variable curvature is more sufficient in volume utilization, and it can save about 13% volume. Considering the use requirements of the actual vehicle waste heat recovery system, the double-variable curvature spiral tube heat exchanger is more suitable for practical engineering applications than the single-variable curvature spiral tube heat exchanger.

目的 提高环氧树脂的耐磨性并改善其力学性能,探究纳米氧化铝掺杂酚醛/环氧复合材料的摩擦磨损行为并揭示其减摩耐磨机制.方法 以酚醛树脂(PF)改性环氧树脂(EP)为聚合物基体,将改性的纳米氧化铝(Nano-Al2O3)掺杂其中,制备不同配比的Nano-Al2O3掺杂PF/EP聚合物基复合材料.利用红外光谱仪(FTIR)对复合材料进行化学结构表征.通过泰伯磨损试验和硬度分析,对比不同含量Nano-Al2O3掺杂对PF/EP基复合材料耐磨性能的影响.借助扫描电镜(SEM)分析复合材料的断面形貌和磨损表面,探究复合材料的磨损机理和减摩耐磨机制.结果 FTIR测定证实了硅烷成功改性Nano-Al2O3,并参与到PF与EP的固化反应中.硬度分析及磨损试验表明,硅烷改性Nano-Al2O3和PF的加入都提高了复合材料的硬度和耐磨性.与纯EP相比,酚醛质量分数为30％,掺杂3％Nano-Al2O3的复合材料的泰伯磨损指数最低,硬度提高了86％,磨损量降低了38.7％.SEM显示Nano-Al2O3与PF/EP聚合物基体结合良好,断裂面产生的银条纹和分散均匀的Nano-Al2O3提高了复合材料的韧性和致密性.掺杂Nano-Al2O3后的复合材料,其磨损面更平整,磨损机理主要为黏着磨损.复合材料基体中的Nano-Al2O3和PF通过提高刚度和承载能力改善了磨损性能.另一方面,Nano-Al2O3形成的润滑膜和聚合物自润滑特性提高了复合材料的耐磨性能.结论 优异的摩擦学性能归因于较强的显微硬度和润滑膜的协同作用.

Nanofluids can effectively enhance the heat transfer performance of different types of heat pipes according to the existing research. This paper provides a comprehensive literature review on the application of nanofluids in thermosyphon heat pipe, pulsating heat pipe and wick heat pipe, respectively. The effect of important variables such as different nanoparticles, concentrations, packing ratios, inclination angles and thermal loads on heat pipe performance is discussed. Studies shows that there is a certain concentration of nanoparticles for highly efficient utilization. High concentration of nanoparticles leads to higher thermal resistance mainly due to the increase in dynamic viscosity and the possibility of particle agglomeration. The enhanced heat transfer performance is caused by the enhanced Brownian motion, improved surface wettability, increased nucleation sites and inherently high thermal conductivity of nanofluids. Finally, the current problems and future trends of heat pipe technology based on nanofluids are discussed.

Proton exchange membrane fuel cells (PEMFC) are widely used in transportation systems owing to their desirable characteristics such as high efficacy and low operating temperature. However, the fuel cell systems exhibit load changes as well as voltage and power losses so as to reduce dependence on the battery. The aim of the present study was to explore the composition and basic working principle of PEMFC. A PEMFC electrochemical reaction model was then established according to the electrochemical reaction principle of fuel cell to evaluate the effects of Nernst electromotive force, activation overvoltage, Ohmic overvoltage, concentration overvoltage, and electric double layer. The effects of activation loss, concentration loss, and Ohmic loss on the fuel cell were evaluated through simulation analysis. The effect of various factors on the dynamic output of a 60 kW PEMFC was explored through dynamic simulations. The findings showed that a change in current modulated a change in voltage through the Ohmic loss equivalent resistance. The activation loss equivalent resistance and the concentration loss equivalent resistance decreased the voltage loss owing to the presence of the capacitor. The output voltage of the fuel cell decreased with an increase in load current, whereas the output power increased with an increase in load current. Increase in partial pressure of oxygen caused an increase in output power and output voltage of the cell. The internal chemical reaction rate and the voltage output of the fuel cell increases with an increase in the working temperature. The findings of this study provide a basis for conducting further studies to produce efficient fuel cells for application in various systems.

As one of the core components of the proton exchange membrane fuel cell, the bipolar plate has an important influence on the performance, service life and production cost of the fuel cell. This paper analyzes and summarizes the research status of metal bipolar plate coating technology at home and abroad, discusses the problems existing in metal bipolar plate coating technology, and points out the development trend of metal bipolar plate coating technology.

Because of its superior cold-start effect and lack of pollution, the proton exchange membrane fuel cell (PEMFC) engine has gained a lot of interest as the most common application type of hydrogen fuel cell engines. However, the difficulty in forecasting the remaining life and monitoring the operation state for a lengthy period limits its commercialization. As a result, PEMFC Prognostics and Health Management (PHM) is critical. A method based on bibliometrics is introduced into the research on this topic. In this work, the research in this field is divided into three stages. The characteristics of different stages are summarized through keywords, subject background, and other aspects. We can observe the transformation of the field from the idea based on analytical reduction to systematic theoretical control. Based on the results of bibliometric analysis, we have conducted a literature review, and we can see the typical research results and development direction of each topic clustering.

合理的流场设计对提升氢燃料电池输出性能有着至关重要的作用.为了探究流道内凸台在提升氢燃料电池发电性能的具体影响途径,本文在平滑流道的基础上建立了带有半圆形、梯形和矩形凸台的燃料电池模型,对比研究了凸台及其形状对燃料电池性能提升、氧气分布、反应气体速度及进出口压力分布的影响.结果表明,凸台的存在一方面减少了气体流道的流通面积,迫使反应气向催化层和双极板脊下扩散;另一方面使流道前后存在一定的压力梯度,增加了进出口压差,进而也促进了反应气向催化层扩散;这两种作用共同提高了燃料电池催化层反应气体浓度,最终使燃料电池浓差极化区的输出电流密度获得提升;其中矩形凸台的提升效果最为明显,提升了 9.87％.

The bipolar plate is the fundamental structural element of the hydrogen fuel cell, and its flow field design has a significant impact on the performance of the fuel cell. The hydrogen fuel cell is employed as an important energy supply source for vehicle power. The classification and operation of hydrogen fuel cells, as well as the benefits and drawbacks of conventional flow fields, are discussed in this paper and contrasted with the state of bipolar plate flow field research in recent years. Comprehensive analysis is done on the optimization of the fuel cell bipolar plate flow field based on the conventional flow field. All are favorable to enhancing fuel cells' ability to generate electricity and aid in the progressive development of a full set of structural design guidelines.

Multi-target tracking, a high-level vision job in computer vision, is crucial to understanding autonomous driving surroundings. Numerous top-notch multi-object tracking algorithms have evolved in recent years as a result of deep learning’s outstanding performance in the field of visual object tracking. There have been a number of evaluations on individual sub-problems, but none that cover the challenges, datasets, and algorithms associated with visual multi-object tracking in autonomous driving scenarios. In this research, we present an exhaustive study of algorithms in the field of visual multi-object tracking over the last ten years, based on a systematic review approach. The algorithm is broken down into three groups based on its structure: methods for tracking by detection (TBD), joint detection and tracking (JDT), and Transformer-based tracking. The research reveals that the TBD algorithm has a straightforward structure, however the correlation between its individual sub-modules is not very strong. To track multiple objects, the JDT technique combines multi-module joint learning with a deep network framework. Transformer-based algorithms have been explored over the past two years, and they have benefits in numerous assessment indicators, as well as tremendous research potential in the area of multi-object tracking. Theoretical support for algorithmic research in adjacent disciplines is provided by this paper. Additionally, the approach we discuss, which uses merely monocular cameras rather than sophisticated sensor fusion, is anticipated to pave the way for the quick creation of safe and affordable autonomous driving systems.

固态选择性催化还原(solid selective catalytic reduction,SSCR)后处理技术是一种新型柴油机废气NOx后处理技术,其具备NOx转化效率高、工作温度窗口宽、不易堵塞管路等优点,有较好的应用前景,开展SSCR技术研究对环境保护具有重要意义.详细介绍了固态选择性催化还原(SSCR)技术的工作原理,分析了中外固态储氨材料和SSCR技术的发展历程和研究现状;结合尿素选择性催化还原技术(Urea-SCR)后处理技术的不足之处,讨论了SSCR后处理技术所具备的优势,指明了该技术在今后发展中所面临的挑战及应对策略,并进一步展望了SSCR后处理技术的发展趋势.