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The ozone oxidation, or ozonation, of thiosulfate is an important reaction for wastewater processing, where it is used for remediation of mining effluents, and for studying aerosol chemistry, where its fast reaction rate makes it an excellent model reaction. Although thiosulfate ozonation has been studied since the 1950s, challenges remain in developing a realistic reaction mechanism that can satisfactorily account for all observed products with a sequence of elementary reaction steps. Here, we present novel measurements using trapped microdroplets to study the pH-dependent thiosulfate ozonation kinetics. We detect known products and intermediates, including SO32-, SO42-, S3O62-, and S4O62-, establishing agreement with the literature. However, we identify S2O42- as a new reaction intermediate and find that the currently accepted mechanism does not directly explain observed pH effects. Thus, we develop a new mechanism, which incorporates S2O42- as an intermediate and uses elementary steps to explain the pH dependence of thiosulfate ozonation. The proposed mechanism is tested using a kinetic model benchmarked to the experiments presented here, then compared to literature data. We demonstrate good agreement between the proposed thiosulfate ozonation mechanism and experiments, suggesting that the insights in this paper can be leveraged in wastewater treatment and in understanding potential climate impacts.

Highly accelerated lifetime test (HALT) for lifetime evaluation was performed on the state-of-art automotive MLCC prototypes by varying Dy/Mg (donor/acceptor) ratio added to BaTiO 3. The results clearly showed that the mean time to failure (MTTF) more than 280 times as the Dy/Mg ratio increased from 1.0 to 10.0. Since oxygen vacancies typically form in-gap state/defect at the donor level, the activation energy value under thermal activation process as a function of voltage was calculated and compared by non-destructive testing (I – V curve) for an accurate evaluation of the extrinsic behavior. It was found that barrier height at the Ni/BT interface decreases as the voltage increases, resulting in a decrease in activation energy. As the Dy/Mg ratio increases, the density of defects/in-gap states formed at the donor level in the bandgap by oxygen vacancies decreases, which may lead to a decrease in the number of electrons excited by the external voltage. Furthermore, it was verified that the calculated Schottky barrier height of the 10.0 Dy/Mg ratio under voltage has higher value than that of the 2.6 Dy/Mg ratio. Based on the results of this study, we propose a new indicator for the design of automotive MLCCs with high lifetime reliability that can be used for comparative analysis of additive compositions through non-destructive test (I – V curve) with low evaluation time/cost. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, an investigation on the acoustic performance of a simple expansion chamber muffler with side outlet has been presented. The investigation for the muffler is done in the 10–2400 Hz frequency range. The muffler is analyzed analytically, computationally, and experimentally. The computational and analytical modellings of the muffler have been done by using the finite element and transfer matrix methods, respectively for the determination of transmission loss. As the transfer matrix method is unable to capture the higher order modes above the cut-off frequency of the muffler, the finite element method has been adopted as the computational method. Additionally, the accuracy in the analytical and computational modelling of the muffler is checked with the experimental investigation. The two-load method is used in this study for muffler to determine the transmission loss and band power. The side outlet of the muffler introduces an extra impedance due to the shunt element and hence the effectiveness of the muffler can be improved. This muffler shows an overall improvement of 24.73 dB in the transmission loss when compared with the transmission loss of the simple expansion chamber muffler with an axial outlet in 10–2400 Hz frequency range. Specifically, the simple expansion chamber muffler with side outlet is more effective than the simple expansion chamber muffler with an axial outlet in 350–680 Hz, 1040–1350 Hz, 1570–1590 Hz, and 1850–2400 Hz frequency ranges. The comparison among the different techniques shows a fair agreement in the results. The transmission loss, variation of the band power in the 1/3rd octave band, and sound pressure level contours for the muffler at the selected frequencies have been presented. This study offers an advantage in the design of the automotive mufflers. [ABSTRACT FROM AUTHOR]

This review article provides a deep dive into the diverse landscape of Additive Manufacturing (AM) technologies and their significant impact on the automotive and aviation sectors. It starts by exploring various AM methodologies such as Fused Deposition Modeling (FDM), Stereolithography (SLA), Digital Light Processing (DLP), Selective Laser Sintering (SLS), Metal Jet Fusion (MJF), Binder Jetting (BJ), and Directed Energy Deposition (DED), with a specific focus on their applicability, strengths, and challenges within these industries. The article then delves into the practical applications of AM in rapid prototyping, functional part production, and component repair. The results highlight the versatility and precision of SLA and DLP, the strength and durability of SLS, and the potential of metal-based technologies like LPBF, SLM, EBM, and DMLS in manufacturing critical components. The integration of AM with automotive and aviation design underscores the transformative nature of these technologies, driving advancements in lightweight, intricate, and high-performance components. The review concludes by emphasising AM's significant opportunities and acknowledging the ongoing challenges in material properties, post-processing, and production scalability, thereby underscoring the necessity for future research and innovation in these sectors. [ABSTRACT FROM AUTHOR]

In this paper, a novel surrogate model for shape-parametrized vehicle drag force prediction is proposed. It is assumed that only a limited dataset of high-fidelity CFD results is available, typically less than ten high-fidelity CFD solutions for different shape samples. The idea is to take advantage not only of the drag coefficients but also physical fields such as velocity, pressure, and kinetic energy evaluated on a cutting plane in the wake of the vehicle and perpendicular to the road. This additional "augmented" information provides a more accurate and robust prediction of the drag force compared to a standard surface response methodology. As a first step, an original reparametrization of the shape based on combination coefficients of shape principal components is proposed, leading to a low-dimensional representation of the shape space. The second step consists in determining principal components of the x-direction momentum flux through a cutting plane behind the car. The final step is to find the mapping between the reduced shape description and the momentum flux formula to achieve an accurate drag estimation. The resulting surrogate model is a space-parameter separated representation with shape principal component coefficients and spatial modes dedicated to drag-force evaluation. The algorithm can deal with shapes of variable mesh by using an optimal transport procedure that interpolates the fields on a shared reference mesh. The Machine Learning algorithm is challenged on a car concept with a three-dimensional shape design space. With only two well-chosen samples, the numerical algorithm is able to return a drag surrogate model with reasonable uniform error over the validation dataset. An incremental learning approach involving additional high-fidelity computations is also proposed. The leading algorithm is shown to improve the model accuracy. The study also shows the sensitivity of the results with respect to the initial experimental design. As feedback, we discuss and suggest what appear to be the correct choices of experimental designs for the best results. [ABSTRACT FROM AUTHOR]

To promote the improvement and development of China's automotive industry policy, this study conducts a systematic review and hierarchical analysis of both domestic and international automotive industry policies. First, the automotive industry policies of the United States, Germany, South Korea, and Japan are summarized in terms of their industrial structure adjustment, technological innovation, taxes and financial subsidies, and infrastructure construction. Benchmarking the policies of international automotive industry powers provides a reference and basis for integrating their experiences in the formulation of China's automotive industry policy. Second, beginning with China's "Automotive Industry Policy" issued in 1994, the key automotive industry policies at different points in history and under different strategies are analyzed. Through policy adjustment and target setting, the changing focus through the historical development of China's automotive industry is determined, along with the development of the industry and technological progress. Then, from the perspectives of strategic planning, promotion and application, credit management, infrastructure, management standards, and standard systems, the advantages and disadvantages of current development policies for new energy and intelligent connected vehicles are clarified. The challenges and limitations of China's automotive industry policy are summarized, including a lack of investment in technology research and development, low level of infrastructure support, and insufficient consumer protection. China's automotive industry policy is then into three different historical stages: i) 1994 to 2008, ii) 2009 to 2013, and iii) 2014 to present; and the characteristics of each stage are summarized. Finally, based on China's national conditions and considering the future development trends of the international automotive industry, the study concludes that under the strong drivers of carbon peak and neutrality goals, China's future automotive industry policy should feature energy saving and emission reduction as the main goals. Independent innovation should be the main enabler, strengthening and supplementing the supply chain through intelligent connectivity. [ABSTRACT FROM AUTHOR]

To enhance the segmentation accuracy of car front face elements such as headlights and grilles for car front face design, and to improve the superiority and efficiency of solutions in automotive partial modification design, this paper introduces MD-TransUNet, a semantic segmentation network based on the TransUNet model. MD-TransUNet integrates multi-scale attention gates and dynamic-channel graph convolution networks to enhance image restoration across various design drawings. To improve accuracy and detail retention in segmenting automotive front face elements, dynamic-channel graph convolution networks model global channel relationships between contextual sequences, thereby enhancing the Transformer's channel encoding capabilities. Additionally, a multi-scale attention-based decoder structure is employed to restore feature map dimensions, mitigating the loss of detail in the local feature encoding by the Transformer. Experimental results demonstrate that the MSAG module significantly enhances the model's ability to capture details, while the DCGCN module improves the segmentation accuracy of the shapes and edges of headlights and grilles. The MD-TransUNet model outperforms existing models on the automotive front face dataset, achieving mF-score, mIoU, and OA metrics of 95.81%, 92.08%, and 98.86%, respectively. Consequently, the MD-TransUNet model increases the precision of automotive front face element segmentation and achieves a more advanced and efficient approach to partial modification design. [ABSTRACT FROM AUTHOR]

AbstractThis study explores the adoption of carbon fiber reinforced plastic (CFRP) in automotive seat backrests, aiming to improve compliance with regulatory standards and enhance performance. By replacing conventional materials with CFRP, and employing mechanical performance tests alongside the principle of equal stiffness, the study tackles material failure issues. A novel multi-criteria decision-making method, coupled with an optimal Latin hypercube experimental design, is used to optimize the layup sequence. The optimized design not only meets regulatory requirements but also significantly enhances driver and passenger safety and comfort during collisions. [ABSTRACT FROM AUTHOR]

Highlights Rapid prototyping, also known as additive manufacturing, is a nascent technology that is gaining traction in the context of environmental concerns and waste reduction, as well as the growing trend towards customized design. The additive manufacturing method, which has applications in diverse fields such as aviation, architecture, biomedical and automotive engineering, has also begun to be utilized in the construction of yachts and yacht hulls within the maritime industry. In this experimental study, the influences of sea water on polylactic acid (PLA) and carbon fiber reinforced polylactic acid (PLA/CF) parts manufactured at different infill rates (20%, 60% and 100%) were investigated. The parts were exposed to sea water for three different periods (1, 5, and 10 days) and subsequently subjected to wear tests. The dimensional accuracy, surface roughness, hardness, water absorption, volume loss, and friction coefficient of parts were measured and calculated. Additionally, the worn surfaces of the parts were investigated using field emission scanning electron microscope (FESEM) images. The findings indicate that PLA and PLA/CF parts can be produced with high dimensional accuracy. Furthermore, it can be reported that the water absorption of PLA/CF parts increased, particularly with an increase in the infill rate, while the volume loss decreased. Obtained results indicate the necessity of optimizing the 3D printing parameters and the relationship between the ambient conditions and the wear performance of the 3D printed parts. 3D printing is a highly promising method for the production of polymer composites. A pioneering study into the effect of infill rate and water absorption on the wear performance. Coefficient of friction values of PLA and PLA/CF parts ranged between 0.37 and 0.75. PLA/CF mostly exhibited higher volume loss than PLA with water absorption. Volume loss declines with a raise in the infill rate from 20% to 100%. [ABSTRACT FROM AUTHOR]

When designing the structure of a new vehicle, car manufacturers need to ensure the compliance with strict safety requirements. Aiming to support the engineers in the early phase of this process, we propose a transfer learning framework for crashworthiness. This work explores the possibility to infer knowledge on future situations by exploiting data coming from past development processes. During the early phases of automotive development, assessing the crash safety implies dealing with the challenge of low data availability. Here, the engineers have no hardware test to rely on and can access only few finite element simulations. Under these circumstances, an attractive concept to investigate is the development of a machine learning approach able to learn from the past designs and to transfer the acquired knowledge to the new ones. Transfer learning can serve to this aim. With it, one learns the basic knowledge from a source domain A, and transfers it to a target domain B, characterized by low data availability. Here, we propose a transfer learning framework and apply it to an explicatory industrial crash example. The components produced in the past constitute the source domain; the new component design is the target domain. The proposed methodology can serve as an innovative solution to support car manufacturers in the early phase of vehicle development and thus improve the performance in crashworthiness scenarios. [ABSTRACT FROM AUTHOR]

Drive systems are an important part of general mechanical engineering, automotive engineering, and various other fields, with shaft–hub connections being an important part of such systems. Decisive aspects in the development of such systems today are, for example, high transmittable forces and torques, low masses, and the cheapest possible production of components. A possibly threefold increase in the force and torque transmission capacity can be achieved by using press–fit connections with an elastic–plastic design as opposed to regular elastically designed alternatives. An elastic–plastic design of the press–fit connection is achieved by using a large interference. A large transition geometry on the shaft (which replaces the conventional chamfer) is required to join such an interference. The material and space requirements have a negative impact on lightweight applications and limited building spaces. Therefore, the objective of the research presented in this paper is to design and analyze a detachable joining device that substitutes this geometry. A simulation study was conducted to determine the geometry of the joining device that improves the stress state and consequently the force and torque transmission capacity of the connection. Moreover, the influence of manufacturing tolerances of the joining device and the shaft, corresponding risks, and measures to mitigate them are analyzed using finite element analysis. The results show that large transition radii, enabled by using a joining device, lead to a homogenous distribution of plastic strain and pressure in the press–fit connection, even for large interferences ξ and soft hub materials like wrought aluminum alloys. The influence of manufacturing tolerances on the stress state was quantified, leading to design guidelines that minimize the risk of, e.g., the front face collision of a shaft and hub, while maximizing the power transmission of the connection. The results show the capability of a detachable joining device to enable elastic–plastic press–fit connections and the corresponding threefold increase in the force and torque transmission capacity in lightweight applications, resulting from the substitution of the installation space consuming and mass increasing the transition geometry of the shaft. [ABSTRACT FROM AUTHOR]

Lattice structures, characterized by their lightweight nature, high specific mechanical properties, and high design flexibility, have found widespread applications in fields such as aerospace and automotive engineering. However, the lightweight design of lattice structures often presents a trade-off between strength and stiffness. To tackle this issue, a bio-inspired curved-elliptical (BCE) lattice is proposed to enhance the mechanical performance and deformation stability of three-dimensional lattice structures. BCE lattice specimens with different parameters were fabricated using selective laser melting (SLM) technology, followed by quasi-static compression tests. Finite element (FE) numerical simulations were also carried out for validation. The results demonstrate that the proposed BCE lattice structures exhibit stronger mechanical performance and more stable deformation modes that can be adjusted through parameter tuning. Specifically, by adjusting the design parameters, the BCE lattice structure can exhibit a bending-dominated delocalized deformation mode, avoiding catastrophic collapse during deformation. The specific energy absorption (SEA) can reach 24.6 J/g at a relative density of only 8%, with enhancements of 48.5% and 297.6% compared with the traditional energy-absorbing lattices Octet and body-center cubic (BCC), respectively. Moreover, the crushing force efficiency (CFE) of the BCE lattice structure surpasses those of Octet and BCC by 34.9% and 15.8%, respectively. Through a parametric study of the influence of the number of peaks N and the curve amplitude A on the compression performance of the BCE lattice structure, the compression deformation mechanism is further analyzed. The results indicate that the curve amplitude A and the number of peaks N have significant impacts on the deformation mode of the BCE lattice. By adjusting the parameters N and A, a structure with a combination of high energy absorption, high stiffness, and strong fracture resistance can be obtained, integrating the advantages of tensile-dominated and bending-dominated lattice structures. [ABSTRACT FROM AUTHOR]

This study developed a dynamic simulation model of hydrogen refueling station (HRS) for the refueling process from high-pressure bank (HPB) to vehicle tank (VT) of fuel cell electric vehicle (FCEV). The model validation was confirmed by comparison with the results from the experimental test of Society of Automotive Engineers (SAE) J2601 protocol. After the validation, the same components and their specifications are used for the analysis of the refueling characteristics in various initial and boundary conditions by a commercial process simulator (Aspen HYSYS). The pressure and temperature profiles of the VT and external temperature conditions were defined for the analysis of the hydrogen refueling characteristics. The dynamic simulation model was in a good agreement with the experimental data and supports to evaluate hydrogen refueling efficiency by the analysis of refueling characteristics. [ABSTRACT FROM AUTHOR]

Enhancing the vibration behaviour of rotating systems while meeting conflicting design needs is a difficult task, which is often treated as an inverse issue and formulated as a nonlinear optimization problem with constraints. To tackle this intricate challenge, a novel hybrid algorithm (HDE-Jaya) has been developed, combining the differential evolution (DE) and Jaya methods. The Jaya model is integrated into DE as a mutation operator to boost exploration and exploitation. In addition, the crossover probability is generated randomly at each iteration to preserve diversity. This makes HDE-Jaya a parameter-free algorithm. The performance of HDE-Jaya was validated by optimizing six common mechanical engineering design problems and further evaluated on an automotive turbocharger design, aiming to reduce vibrations, minimize binding stress and improve dynamic stability. The results indicate that HDE-Jaya is superior to other algorithms, including DE and the Jaya algorithm, in terms of solution accuracy and computational efficiency. [ABSTRACT FROM AUTHOR]

In the context of Industry 4.0, intelligent manufacturing systems are the key to creating higher value-added processes and services that enable product customization. This is made possible by dynamically reconfiguring manufacturing systems based on customer needs. Robotic Process Automation (RPA) in manufacturing should only be implemented after correctly identifying those processes that can be automated. Management support for the implementation of RPA is required at all stages. RPA must be integrated into the company in convergence with the Enterprise Resource Planning (ERP) system in place. The study presents an applied research, the aim of which is a project to integrate advanced technologies for automated manufacturing of three-dimensional (3D) digital model objects into the production process management system of a factory in the automotive industry. The automotive sector needs to enable the use of artificial intelligence in terms of open innovation in both manufacturing and management. Research results show that robotic process automation is a key factor in transforming the business process in an automotive factory. The implementation of RPA in the automotive industry is a decision with a major impact on the efficiency of business processes in the Industry 4.0 era. [ABSTRACT FROM AUTHOR]

This work is a study aimed at optimizing the process of superarc metallization, with a focus on the effect of voltage on the properties of the spraying coatings. In this work, 30HGSA grade steel wire was used for the coating of 45 steel, widely used in mechanical engineering. The use of supersonic arc metallizer SX-600 allowed to obtain coatings at different voltages (32 V, 38 V and 44 V) and the same current strength. Various metallization process parameters such as material feed rate, voltage, current, distance and nozzle geometry are discussed in this paper. Using various analytical techniques including X-ray diffraction analysis, microscopy, microhardness and corrosion resistance tests, the qualities of the coatings were evaluated. Particular attention was paid to analyzing the phase composition of the coatings, porosity, substrate bond strength and tribological characteristics. It was found that the voltage during the supersonic arc metallization process has a significant effect on these characteristics. The selected optimum voltage allows to obtain dense and homogeneous coatings with improved performance properties. The results of the study revealed that the best physical and mechanical properties were exhibited by the sample processed at 38 V, which showed lower porosity and improved strength characteristics compared to the other samples. These findings can be used to improve manufacturing processes in industries such as automotive and mechanical engineering, where restoration and improved performance of worn parts is required. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive analysis of the electric-drive-wheel (EDW) with idler gear. From the perspective of automotive engineering, the EDW is an integrated execution unit that combines the function of powertrain and suspension. As a result, the research on EDW involves the intersection of multiple disciplines. The evolution of idler gear configuration requires some geometric constraints. Under this premise, the longitudinal and vertical dynamic characteristics of the system were studied, respectively. There are several factors that influence the system performance, such as the gear parameters, the position of the electric motor, and the suspension K&C value. The principles of each parameter on the output indicators were studied, with an optimized plan and simulation comparison to check the correctness of theory. In the end, the prototype was equipped with a test bench, covering a wide range of working operations to examine the expected performance of EDW design. The step response test of the EDW result showed a balanced performance in transmission smoothness and responsiveness agility. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to investigate work engagement and commitment of automobile technology teachers as correlates of teacher effectiveness in technical colleges in Enugu State. Three specific purposes, three research questions, three hypotheses guided the study. The study adopted survey design. Population was made up of 57automobile technology teachers from 13 technical colleges in Enugu State. Utrecht Work Engagement and Teachers' Perceptions of Professional Commitment and Teacher Effectiveness Scales were adapted. Data were analysed using means, correlations and regression analysis. Findings reveal that a moderate relationship (.425) exists between work engagement and teacher effectiveness of automobile technology teachers. Also a moderate relationship (.537) exists between teachers' commitment and teachers' effectiveness of automobile technology teachers. Furthermore, moderate relationship (.433) exist between teachers'; work engagement and commitment of automobile technology teachers. The hypotheses tested revealed that teachers'; work engagement is a significant predictor for teachers'; effectiveness and teachers' commitment, teachers' commitment is a significant predictor for teacher effectiveness. Based on the findings, Enugu State Ministry of Education should among other things, try to improve the work engagement and commitment of their automobile teachers through empowerment, rewards and benefit schemes. [ABSTRACT FROM AUTHOR]

A packaged transmit array (TA) antenna is designed for automotive radar applications operating at 77 GHz. The compact dimensions of the proposed configuration make it compatible with standard quad flat no-lead package (QFN) technology. The TA placed inside the package cover is used to focus the field radiated by a feed placed in the same package. The unit cell of the array is composed of two pairs of stacked patches separated by a central ground plane. A planar patch antenna surrounded by a mushroom-type EBG (Electromagnetic Band Gap) structure is used as the primary feed. An analytical approach is employed to evaluate the primary parameters of the suggested TA, including its directivity, gain and spillover efficiency. The final design has been refined using comprehensive full-wave simulations. The simulated gain is 14.2 dBi at 77 GHz, with a half-power beamwidth of 22°. This proposed setup is a strong contender for highly integrated mid-gain applications in the automotive sector. [ABSTRACT FROM AUTHOR]

We investigated the pyrolysis of propyne and propene using aerosol mass spectrometry coupled with tunable synchrotron vacuum ultraviolet photoionization. The results show that propyne forms particles at pyrolysis temperatures approximately 100 K below the lowest temperature at which propene produces particles. The aerosol mass spectra show that the carbon-to-hydrogen (C/H) ratios of the pyrolysis products from both reactants increase with temperature between the particle onset temperature and 1275 K. In this temperature range, the mass peaks corresponding to species with 18 or more carbon atoms are more saturated (i.e., have lower C/H ratios) than species predicted by the stabilomer grid. The observation of relatively high saturation (low C/H ratios) at temperatures near particle onset is consistent with the presence of aliphatically linked hydrocarbons during the preliminary stages of soot formation. The masses of the species presumed to be aliphatically linked suggest that these linked species are adducts of species smaller than chrysene (C18H12). We performed a comparative analysis of the initial PAH-growth pathways consistent with aerosol mass spectra and associated mass-specific photoionization-efficiency curves. The results from the comparative analysis indicate that the development of PAHs up to the size of acenaphthylene (C12H8) follow similar formation pathways for propyne and propene, but the isomeric composition of species larger than acenaphthylene diverges for the two reactants.

The present experimental study investigated the dynamics of single- and multi-port gaseous jet diffusion flames exposed to acoustic excitation via a standing wave situated in a closed waveguide at atmospheric pressure. High-speed imaging of the oscillatory flame was analysed via proper orthogonal decomposition (POD), revealing distinct signatures in both mode shapes and phase portraits for transitions in the acoustically coupled combustion process. For Reynolds numbers between 20 and 100, and for low to moderate forcing amplitudes, the flame exhibited sustained oscillatory combustion (SOC) that was highly coupled to the acoustic forcing. Frequency analysis of the temporal POD modes accurately recovered the forcing frequency and its higher harmonics. At higher forcing amplitudes, a multi-frequency response was observed, resulting from a combination of the forcing frequency and much lower frequency oscillations due to periodic lift-off and reattachment (PLOR) of the flame, preceding a transition to flame blow-off (BO). For both single- and triple-jet flames, transitions from SOC to PLOR to BO were characterized by significant alterations in primary modal energetic content, deflection and eventual smearing in phase portraits, and the development of additional frequencies in modal spectra, although transitional behaviour for the triple jet flames involved additional complexity in the dynamics due to its structure. These features provide the potential for the development of reduced-order models that can characterize and predict acoustically coupled combustion behaviour.