Hasil untuk "Mechanical industries"

Bouchra El Houda Lamhamedi, Walter Timo de Vries

Abstract Background Sustainable development is not possible without sustainable energy, and while renewable energy minigrid and microgrid systems are regarded as a promising solution for achieving energy transition and supporting rural development in the global south, the complex relationship between the adoption of renewable energy systems and land tenure systems within rural communities remains a critical aspect that has often been overlooked in this context. This study addresses this gap by examining how small-scale community-based renewable energy systems influence land tenure transformations and whether shifts in land tenure patterns drive changes in renewable energy adoption and management strategies. Results This research adopts a qualitative comparative case study methodology, examining six community-based solar energy projects in Ethiopia, Uganda, Kenya, Namibia, Indonesia, and Peru. Using an adapted socio-ecological systems framework based on Ostrom’s principles, the study analyzes six outcome parameters: governance, land tenure, socio-spatial relations, economic dependencies, perception, and behavior. The findings reveal complex interactions between land tenure and renewable energy adoption, demonstrating that the introduction of renewable energy systems has the potential to reshape land tenure paradigms. Specifically, changes in socio-spatial relations and economic dependencies were identified as key factors that influence community responses to renewable energy projects. These shifts also affect local governance structures, perceptions, and community behavior towards both land and energy systems. Conclusions The results highlight the need for a comprehensive understanding of the interactions between land tenure and renewable energy initiatives to foster effective rural development. Recognizing these dynamics can inform policy and practice, ensuring that renewable energy interventions are aligned with local land tenure realities and contribute to sustainable socio-economic transformations.

Joseph Berthel, Joshua Taggart-Scarff, Jian Yu et al.

Theoretical studies have shown that plate-lattice structures exhibit exceptional mechanical properties such as high strength-to-weight ratios. Their fabrication, however, is challenging and has only been realized for metals via the Laser Powder Bed Fusion (LPBF) process. A deeper understanding of the deformation mechanisms of LPBF fabricated plate-lattice structures, including their post-yielding and energy absorption characteristics, is needed to evaluate their applicability in defense, aerospace, and biomedical industries. In this study, AlSi10Mg plate-lattice structures with four unit cell topologies were fabricated using LPBF and tested in quasi-static compression to determine mechanical properties, deformation behaviors, and energy absorption capabilities. Microcomputer tomography revealed surface variations resulting from adhered powder and dross formation were comparable in scale to plate thicknesses. Tested plate-lattices experience primarily stretch-dominant deformation consistent with theoretical Gibson-Ashby models. Stretch-dominant deformation is maintained for large compressive strains post-yielding until brittle fracture occurs in unit cell layers or diagonal bands, leading to high localized strength. For the simple cubic geometry, high yield stresses that were maintained post-yielding resulted in the highest specific energy absorption yet observed in lattice materials, reaching up to 27.2 J/g at a density of 1.23 g/cc. This research highlights AlSi10Mg plate-lattices as excellent candidates for light-weight energy absorption applications.

Oumayma Hamlaoui, Riadh Elleuch, Hakan Tozan et al.

This paper provides an in-depth analysis of the microstructural characteristics and the chemical content of Polybutylene Terephthalate (PBT) composites that have different contents of Glass Fiber (GF). Blending of VALOX 420 (30 wt% GF/PBT) with unreinforced VALOX 310 allowed the composites to be prepared, with control of the concentration and distribution of the GF. The GF reinforcement and PBT matrix were characterized by an advanced microstructural spectrum and spatial analysis to show the influence of fiber density, dispersion, and chemical composition on performance. Findings indicate that GF content has a profound effect on microstructural properties and damage processes, especially traction effects in various regions of the specimen. These results highlight the significance of accurate control of GF during fabrication to maximize durability and performance, which can be used to inform the design of superior PBT/GF composites in challenging engineering applications. The implications of these results are relevant to a number of high-performance sectors, especially in automotive, electrical, and consumer electronic industries, where PBT/GF composites are found in extensive use because of their outstanding mechanical strength, dimensional stability, and thermal resistance. The main novelty of the current research is both the microstructural and chemical assessment of PBT/GF composites in different fiber contents, and this aspect is rather insufficiently studied in the literature. Although the mechanical performance or macro-level aging effects have been previously assessed, the Literature usually did not combine elemental spectroscopy or spatial microstructural mapping to correlate the fiber distribution with the damage mechanisms. Further, despite the importance of GF reinforcement in achieving the right balance between mechanical, thermal, and electrical performance, not much has been conducted in detail to describe the correlation between the microstructure and the evolution of damage in short-fiber composites. Conversely, this paper will use the superior spatial elemental analysis to bring out the effects of GF content and dispersion on micro-mechanisms like interfacial traction, cracking of the matrix, and fiber fracture. We, to the best of our knowledge, are the first to systematically combine chemical spectrum analysis with spatial mapping of PBT/GF systems with varied fiber contents—this allows us to give actionable information on material design and optimized manufacturing procedures.

Vytautas Bučinskas, Uldis Žaimis, Dainius Udris et al.

Natural polymers, polysaccharides, demonstrate piezoelectric behavior suitable for force sensor manufacturing. Carrageenan hydrogel film with α-iron oxide particles can act as a piezoelectric polysaccharide-based force sensor. The mechanical impact on the hydrogel caused by a falling ball shows the impact response time, which is measured in milliseconds. Repeating several experiments in a row shows the dynamics of fatigue, which does not reduce the speed of response to impact. Through the practical experiments, we sought to demonstrate how theoretical knowledge describes the hydrogel we elaborated, which works as a piezoelectric material. In addition to the theoretical basis, which includes the operation of the metal and metal oxide contact junction, the interaction between the metal oxide and the hydrogel surfaces, the paper presents the practical application of this knowledge to the complex hydrogel film. The simple calculations presented in this paper are intended to predict the hydrogel film’s characteristics and explain the results obtained during practical experiments. Carrageenan, as a low-cost and already widely used polysaccharide in various industries, is suitable for the production of low-cost force sensors in combination with iron oxide.

Andrea Freites

Talifatim Machfuroh, Kris Witono, Septyana Riskitasari et al.

Bimetal joints are often used in various industries, such as automotive, power generation, electronics, and manufacturing. This is because bimetal joints allow the joining of two types of metal with different properties. Welding two different types of metal can pose its own challenges, such as the difficulty of controlling welding parameters so that the results are optimal for both types of metal, as well as differences in the thermal and mechanical properties of the two metals. This has led to extensive research on bimetal plate connections. Based on this background, this research aims to determine the effect of variations in flow rate and current strength on the tensile strength of robotic welding bimetal welded joints, as well as determine the results of macro photos of fractures resulting from tensile tests for each variation. The research was carried out experimentally where each variation was repeated with data 3 times. Based on the results and discussion, it is known that the optimal gas flow rate in general is 20 l/min, where the tensile strength reaches 353.1442 MPa–455.5458 MPa. At this flow rate, the dominant fracture occurs in the base metal and is ductile, which indicates good plastic deformation. On the other hand, gas flow that is too low or too high causes joint defects and reduces the tensile strength. Meanwhile, other welding parameters, namely variations in welding current, affect tensile strength. At a gas flow of 10 l/min, increasing the current to 180 A produces the highest tensile strength of 449.4357 MPa with ductile fracture characteristics. However, at a current of 120 A there is a significant decrease due to overheating, especially at higher gas flows such as 20 l/min and 30 l/min, which results in brittle fracture in the heat-affected zone (HAZ). The results of this research contribute to the understanding of the influence of welding parameters on the tensile strength and fracture characteristics of bimetallic joints. This research can be a reference for the development of more efficient and reliable welding processes in various industries, such as automotive, power generation and manufacturing, which require bimetallic joints with optimal quality.

Mohammed Bouziane, Abdelghani Bouziane, Khatir Naima et al.

This study aims to develop an effective method for predicting the temperature and torque of Permanent Magnet Synchronous Motors (PMSMs) using deep learning techniques, which is crucial for optimizing motor performance and ensuring longevity, particularly in the automotive industry. Various Neural Network (NN) architectures, including a Recurrent Neural Network (RNN) with a Bidirectional Long Short-Term Memory (BiLSTM) unit, were employed to model the complex relationships between motor parameters, such as stator winding, current, torque, and permanent magnet temperature. The findings demonstrate that an NN with two hidden layers (64 and 32 neurons) achieved an R2 score of 0.99 for both torque and temperature prediction, while the BiLSTM network effectively modeled temporal dynamics, leading to high-fidelity rotor temperature predictions. This research provides a novel application of BiLSTM RNNs in accurately predicting PMSM temperatures, offering valuable insights for industries reliant on these motors. Integrating these models into motor control systems can enhance operational efficiency, reduce overheating risks, and extend motor lifespan, contributing to energy savings and environmental sustainability by lowering energy consumption and reducing waste.

Chenyang Jiang, Lidong Gu, Hongwei Xiong et al.

Mg matrix composites (MgMCs) with enhanced mechanical and functional properties, as well as improved elastic modulus, have aroused rising attention from the aerospace, new energy vehicles, and consumer electronics industries. The suitability of the fabrication process is crucial for achieving uniform dispersion of various reinforcing materials within the Mg alloy matrix and for forming strong interfacial bonding. This ensures that the produced MgMCs meet the requirements for fabricating various components with different demands for size and properties. This paper comprehensively reviews the present fabrication methods for MgMCs in four categories: stir casting, external addition methods, in-situ synthesis methods and novel fabrication methods. It comprehensively focuses on the fabrication principles, process characteristics and key parameters optimization of each technology. Through in-depth analysis, their advantages, limitations and applications are evaluated. Meanwhile, the latest research achievements in microstructure control and mechanical performance optimization are explored. Eventually, the development directions of the fabrication methods for MgMCs in the future are also discussed.

Guojin Sun, Xiaoming Liu, Zhenggui Li et al.

This study investigated the fabrication and characterization of large ceramic-reinforced TWIP (twinning-induced plasticity) steel matrix composites using the lost-foam casting technique. Various ceramic shapes and sizes, including blocky, flaky, rod-like, and granular forms, were evaluated for their suitability as reinforcement materials. The study found that rod-like and granular ceramics exhibited superior structural integrity and formed strong interfacial bonds with the TWIP steel matrix compared to blocky and flaky ceramics, which suffered from cracking and fragmentation. Detailed microstructural analysis using scanning electron microscopy (SEM) and industrial computed tomography (CT) revealed the mechanisms influencing the composite formation. The results demonstrated that rod-like and granular ceramics are better for reinforcing TWIP steel composites, providing excellent mechanical stability and enhanced performance. This work contributes to the development of advanced composite structures with potential applications in industries requiring high-strength and durable materials.

Ziyang Li, Xujun Lang, Bo Yang et al.

Global energy and environmental issues are becoming increasingly problematic, and the vibration and noise problem of 110 kV transformers, which are the most widely distributed, have attracted widespread attention from both inside and outside the industry. DC bias is one of the main contributing factors to vibration noise during the normal operation of transformers. To clarify the vibration and noise mechanism of a 110 kV transformer under a DC bias, a multi-field coupling model of a 110 kV transformer was established using the finite element method. The electromagnetic, vibration, and noise characteristics during the DC bias process were compared and quantified through field circuit coupling in parallel with the power frequency of AC, harmonic, and DC power sources. It was found that a DC bias can cause significant distortions in the magnetic flux density, force, and displacement distributions of the core and winding. The contributions of the DC bias effect to the core and winding are different at Kdc = 0.85. At this point, the core approached saturation, and the increase in the core force and displacement slowed. However, the saturation of the core increased the leakage flux, and the stress and displacement of the winding increased faster. The sound field distribution characteristics of the 110 kV transformer under a DC bias are related to the force characteristics. When the DC bias coefficient was 1.25, the noise sound pressure level reached 73.6 dB.

Marie-France Turcotte, Annie Lachance

Martin Colla, Davide Tonelli, Astley Hastings et al.

Abstract Energy crops on marginal lands are seen as an interesting option to increase biomass contribution to the primary energy mix. However, in the literature there is currently a lack of integrated assessments of margin land availability, energy crop production potential and supply chain optimisation. Assessing the potential and the cost of these resources in a given region is therefore a difficult task. This work also emphasises the importance on a clear definition and discussion about marginal lands and the related ethical issues embedded in the concept to ensure positive societal impacts of the results. This study proposes a methodology to estimate and analyse, in terms of economic costs, the potential of miscanthus grown on marginal lands from the production to the final point of use. Different datasets are assembled and a supply chain optimisation model is developed to minimize the total cost of the system. Miscanthus is used as a representative energy crop for the Belgian and French case studies. High temperature heat demand is considered as final use. The miscanthus can be traded by truck either in the form of chips or pellets. The results show that the miscanthus on marginal lands could supply high temperature heat up to 38 TWh in France and 1.4 TWh in Belgium with an average cost of around 50 €/t. The different sensitivity analyses showed that the yield variation has the strongest influence on the final cost, together with the distances and the cost of production of miscanthus. The main pattern observed is the local consumption of miscanthus chips and export of the surplus (if any) to the neighbouring regions. Pellets are only of marginal interest for France and are never observed for Belgium. Distances and availability of sufficient feedstocks are the two main parameters impacting the production of pellets.

Sen Wang, Jiyu Zhang, Weibo Hua et al.

Abstract Layered transition-metal oxide materials are ideal cathode candidates for sodium-ion batteries due to high specific energy, yet suffer severe interfacial instability and capacity fading owing to strongly nucleophilic surface. In this work, the interfacial stability of layered NaNi1/3Fe1/3Mn1/3O2 cathode was effectively enhanced by electrolyte optimization. And the interfacial chemistry between the cathode and four widely used electrolytes (EC/DMC, EC/EMC, EC/DEC and EC/PC) was elucidated through experiments and theoretical calculations. The Na+ solvation structures at cathode-electrolyte interface in all four electrolytes exhibited enhanced coordination due to high electron density and strong nucleophilicity of oxide surface, which promoted the electrolytes’ decomposition with decreased oxidation stability. Among them, the EC/DMC electrolyte showed the tightest solvation structure due to smaller molecular chains and stable electrochemistry, which derived an even and robust cathode electrolyte interphase. It effectively protected the cathode and facilitated the reversible Na+ transport during long cycles, enabling the batteries with a high capacity retention of 83.3% after 300 cycles. This work provides new insights into the role of electrode surface characteristics in interface chemistry that can guide the design of advanced electrode and electrolyte materials for rechargeable batteries.

Juan Montero, Matthias Finger

The most solid framework to both analyze and regulate digital platforms is the one which has developed over the past century for the conceptualization and the regulation of the traditional network industries such as telecoms, transport and energy. Digital platforms in multi-sided markets can be considered the new network industries, notably due to the relevance of direct, indirect and algorithmic network effects. As a result, platforms display features which are similar to all industries where network effects are key, namely concentration, market power and subsequently political intervention. Regulatory measures that have already been tested in the traditional network industries can be exported to the new network industries, including regulation to promote competition by reducing barriers to entry, regulation to promote interoperability and structural remedies along with public service obligations imposed on platforms. Examples of this approach can be identified in different initiatives around the world, with the European Union in the lead.

Shashi Prakash Dwivedi, Ambuj Saxena, Shubham Sharma et al.

Chrome containing leather-wastes (CCLW) is a waste obtained from leather industries. These wastes always produced environmental pollution. However, CCLW can be utilized in the production of various materials. In this research, chromium in the form of collagen powder after extracting from CCLW has been utilized to fabricate the composite material. Extracted collagen was mechanically alloyed with alumina ceramic fragments to acquire in a separate unified facility. Response surface methodology (RSM) was employed to obtain the optimum combination of solid-state synthesis processing variables. Optimum mechanical-alloying parameters were found to be ball-to-powder weight-ratio (BPR) of about 5, ball milling speed of about 178 rotation per minute and ball-milling time of about 93 h. The microstructure of ball processed reinforced composite material demonstrated a uniform distribution and proper wettability in aluminum-based matrix material. Tensile strength and hardness of Al/5% Collagen/5% Al2O3 composite material were enhanced by about 38.25% and 45% respectively. However, the density, toughness and ductility of composite material were reduced by 0.16%, 25% and 24.24% respectively. Surface roughness of Al/5 wt.% Collagen/5 wt.% Al2O3 composite was found to be 3.10  μm at a speed of 190 m/min, feed of 0.14 mm/rev and depth of cut of 0.20 mm.

Abolfazl Salmani Bideskan, Pejman Ebrahimzadeh, Reza Teimouri

Laser transmission welding can be effectively used in fabrication of laminated parts. In the present work an attempt was made to fabricate a polymeric laminate structure made of polymathic methacrylate (PMMA) and aluminum 6061-T6 by laser transmission welding process. A series of laser welding experiment has been carried out to analyze effect of laser power, welding speed, focal position and axial pressure on lap shear force and weld seam width. Response surface methodology including regression analysis, analysis of variances and desirability approach function has been utilized here to analyze the processing data. It is found from the results that focal position has greatest influence on both the lap shear force and weld bead width. Optimization is also carried out in two different criteria for achieving desired welding performance. The optimization results obtained by this approach are consistent well with the results measured through confirmatory experiments. Keywords: Laser transmission welding, Polymer-metal lap joint, Response surface methodology, Optimization

Afef Ben Othman, Ayoub Ouni, Mongi Besbes

Abstract Background Several climatologists and experts in the renewable energy field agree that GHI and DNI calculation models must be revised because of the increasingly unpredictable and powerful climatic disturbances. The construction of analytical mathematical models for the prediction of these disturbances is almost impossible because the physical phenomena relating to the climate are often complex. We raise the question over the current and future PV system’s sustainable energy production and whether climate disturbances will be affecting this sustainability and resulting in supply decline. Methods In this paper, we tried to use deep learning as a tool to predict the evolution of the future production of any geographic site. This approach can allow for improvements in decision-making concerning the implantation of solar PV or CSP plants. To reach this aim, we have deployed the databases of NASA and the Tunisian National Institute of Meteorology relating to the climatic parameters of the case study region of El Akarit, Gabes, Tunisia. In spite of the colossal amount of processed data that dates back to 1985, the use of deep learning algorithms allowed for the validation of the previously made estimates of the energy potential in the studied region. Results The calculation results suggested an increase in production as it was confirmed by the 2019 measures. The findings obtained from the case study region were reliable and seemed to be very promising. The results obtained using deep learning algorithms were similar to those produced by conventional calculation methods. However, while conventional approaches based on measurements obtained using hardware solutions (ground sensors) are expensive and very difficult to implement, the suggested new approach is cheaper and more convenient. Conclusions In the existence of a protracted controversy over the hypothetical effects of climate change, making advances in artificial intelligence and using new deep learning algorithms are critical procedures to strengthening conventional assessment tools of the production sites of photovoltaic energy and CSP plants.

Caitlin E. Moore, Danielle M. Berardi, Elena Blanc‐Betes et al.

Abstract In the age of biofuel innovation, bioenergy crop sustainability assessment has determined how candidate systems alter the carbon (C) and nitrogen (N) cycle. These research efforts revealed how perennial crops, such as switchgrass, increase belowground soil organic carbon (SOC) and lose less N than annual crops, like maize. As demand for bioenergy increases, land managers will need to choose whether to invest in food or fuel cropping systems. However, little research has focused on the C and N cycle impacts of reverting purpose‐grown perennial bioenergy crops back to annual cropping systems. We investigated this knowledge gap by measuring C and N pools and fluxes over 2 years following reversion of a mature switchgrass stand to an annual maize rotation. The most striking treatment difference was in ecosystem respiration (ER), with the maize‐converted treatment showing the highest respiration flux of 2,073.63 (± 367.20) g C m−2 year−1 compared to the switchgrass 1,412.70 (± 28.72) g C m−2 year−1 and maize‐control treatments 1,699.16 (± 234.79) g C m−2 year−1. This difference was likely driven by increased heterotrophic respiration of belowground switchgrass necromass in the maize‐converted treatment. Predictions from the DayCent model showed it would take approximately 5 years for SOC dynamics in the converted treatment to return to conditions of the maize‐control treatment. N losses were highest from the maize‐converted treatment when compared to undisturbed switchgrass and maize‐control, particularly during the first conversion year. These results show substantial C and N losses occur within the first 2 years after reversion of switchgrass to maize. Given farmers are likely to rotate between perennial and annual crops in the future to meet market demands, our results indicate that improvements to the land conversion approach are needed to preserve SOC built up by perennial crops to maintain the long‐term ecological sustainability of bioenergy cropping systems.

Jihye An, Sunghoon Im, Haneul Kang et al.

Mechanical parts have a problem of wear when used in extreme environments. Aluminum, most used in the industrial field, is a representative material of light weight, but its wear resistance is not good. To resolve the wear problem of such materials, research and development of surface thin film deposition technology has been increasing. Wear resistance was investigated after the Ti thin film was deposited by sputtering, one of the main methods of this technique. The smaller the surface roughness value and the thicker the thin film, the better the wear resistance. However, when a thin film is deposited for a predetermined time or less, the bonding strength with the base metal is lowered and the wear resistance is confirmed as low.

Kai Roder