Hasil untuk "Mechanical industries"

Vijayakumar Mylsamy, Prabhakaran Sivalingam, Dhanabalakrishnan Mariappan

One of the major bottlenecks in submersible pump manufacturing is the manual welding of rotor copper bars, which leads to inconsistent weld quality, reduced production throughput, and potential health and safety risks for operators. Currently, conventional carbon arc welding is widely used for this operation because of its simplicity and low operating cost; however, it provides limited arc stability, generates excessive heat input, and results in significant variability in joint integrity. This study examines the feasibility of employing a tungsten inert gas (TIG) welding process as a more precise and reliable alternative for rotor copper bar welding. A six-axis robotic TIG welding platform was utilized to conduct systematic experimental trials aimed at identifying and optimizing the critical process parameters that influence weld quality. Optimization was performed using response surface methodology and analysis of variance (ANOVA) to establish statistically significant relationships among the process variables. Test samples fabricated under optimized conditions were evaluated through mechanical testing, macro- microstructural characterization, and electrical conductivity measurements to validate weld integrity and process repeatability. The findings demonstrate that robotic TIG welding provides superior arc control, improved joint performance, and enhanced consistency compared to the conventional process. These outcomes establish the foundation for developing a low-cost, application-specific special-purpose welding system tailored for rotor copper bar fabrication. Overall, this study not only confirms the technical viability of robotic TIG welding for copper but also contributes to improved productivity, stronger quality assurance, and enhanced operator safety in rotor manufacturing.

Vladimir Erofeev, Vasily Smirnov, Rinat Badamshin et al.

The article deals with composite materials based on caustic magnesite binder and wood fillers used in the fabrication of various types of objects in mechanical engineering, construction engineering, and oil and gas industries. Under operational conditions, caustic magnesite composites can be exposed to aggressive actions of microorganisms. This study looked into resistance of wood-filled composites upon exposure to byproducts of filamentous fungi (micromycetes). This research substantiated the choice of model medium for testing – byproducts of metabolism of micromycetes. Designed experiments were carried out. The samples were held in model solutions with different concentrations of aggressive medium agents. Lines of equal values of materials’ resistance were plotted. It was found from experiments that composites without fillers had a lower biocorrosive resistance compared to those filled with pine sawdust.

Tarekul Islam, Mohammad Nuzrul Islam, Muhammed Mohosin Mia et al.

Abstract Denim is a cellulose-based product which is a popular choice for people of all ages in the modern era. There are massive applications of denim in textile goods, household products, medical products, and manufacturing industries. This work aims to determine the effects of industrial washing techniques on various physio-mechanical, thermal, and comfort properties of denim fabric and its seams. Denim made from 100% cellulose-based cotton with a 3/1 twill structure is used for the study. The two seams used are the lapped seam (LSb) and the superimposed seam (SSa). Four industrial washing techniques are used such as rinse wash, enzyme-bleach-stone (less time/30 min) wash, enzyme-bleach-stone (high time/60 min) wash, and acid wash. Fabric strength, seam strength, stiffness, air permeability, water vapor permeability, and thermal conductivity are evaluated according to standard methods. All the tested results are recorded multiple times, and averages are presented. Experimental findings showed that different industrial washing techniques affect various physio-mechanical and thermal properties of cellulosic goods differently. Results also revealed that enzyme-bleach-stone (high time) washed samples show the lowest strength of 432.22 N and 371.13 N in warp and weft direction, respectively, compared to other samples as well as S4 /high time sample shows higher strength loss 64.77% in warp direction and 82.72% in weft direction. Regarding LSb, enzyme-bleach-stone high-time washed samples exhibit the lowest seam strength, 799.80 N and 374.55 N in warp and weft way, respectively, compared to other samples.

Xiangwei Guo, Gang Chen, Liangjun Zhao et al.

When lithium batteries are used in energy storage systems, due to the low voltage of cells, it is necessary to connect multiple cells in series to form a battery pack that meets the application requirements. There is an unavoidable consistency difference between cells of the same type, and after the cells are formed into a group, the consistency difference will have a serious impact on the cycle life, and jeopardize the safety of the battery pack. To improve the consistency difference of series-connected battery packs, a modular hierarchical active equalization method based on inductors is proposed. First, the topology is proposed in combination with the high accuracy of inductor-based equalization, and its working principle and parameter design are analyzed. Second, based on the equalization principle, a matching adaptive equalization control strategy is designed. Again, the equalization performance of the proposed equalization method is analyzed, which shows that the proposed method has the advantages of fast equalization speed, low topological cost and simple control. Finally, an experimental platform for the equalization of a 9-cell series-connected battery pack is established to verify the effectiveness of the proposed equalization method. The proposed method can significantly improve the consistency difference of the series-connected battery pack, and then improve its energy utilization and cycle life.

Gibson Owhoro Ofremu, Babatunde Yusuf Raimi, Samuel Omokhafe Yusuf et al.

The innumerable impact of climate change is a global menace to human health. This paper conveys a comprehensive review of scientific literature to explore the relationship between climate change, air pollutants, and human health. The integral relationship between climate change and health is complex and has a significant impact on every facet of human life. The impact can either be direct (e.g., exposures due to extreme heat, storms, flooding, and air pollution) or indirect (e.g., displacement, food security, and variation in water). The rising temperature of the planet could lead to increasingly severe health impacts from climate change in the future. It is important to take stringent climate actions to mitigate the climate change risk and adapt to the impacts that are already happening. To lessen the speed and severity of climate change, mitigation focuses on cutting greenhouse gas emissions. Options for adaptation include things like advancing to higher ground to stop sea levels from increasing, growing new crops that can grow in a new environment, or using novel construction methods. Investing in novel or enhanced technology, infrastructure, and research is frequently required for adaptation. The review emphasized the importance of considering both short-term and long-term adaptation strategies as well as mitigation efforts, which call for steps to address the root cause by halting or reducing the growth in fossil fuel emissions that might severely and completely increase the earth's scorching temperatures. The results of this study provide insightful viewpoints on adaptation measures, and mitigation strategies for decision-makers, experts in public health, and researchers working in the field of climate change and its effects on human health.

Oliver Marasigan, Shereyl A. Daguinod

HIGHLIGHTS - Gigantochloa apus shows strong potential for structural and engineered uses. - Axial and nodal variations significantly affect bamboo fiber anatomy. - Relative density and strength make G. apus suitable for construction and furniture. - Derived fiber ratios indicate limited papermaking suitability. - G. apus offers broad utilization potential for sustainable industries ABSTRACT This study assessed the morphological, anatomical, derived ratio, and physico-mechanical properties of string bamboo (Gigantochloa apus [Schult.f.] Kurz ex Munro) grown in Baguio City, Philippines, to establish comprehensive property data and explore potential applications. Six mature culms were sampled and tested for its properties following the IAWA, ISO, and ASTM standards. Results revealed that culm diameter and wall thickness decreased significantly by 37.30% and 46.60%, respectively, toward the top portion. Anatomical analysis showed significant decreases in fiber length, fiber diameter, lumen diameter, and cell wall thickness by 15.33%, 13.86%, 24.05%, and 8.43%, respectively, from bottom to top. All derived ratios varied significantly between the node and internode portions. The node portion exhibited higher values for cell wall fraction, Runkel ratio, Muhlsteph ratio, rigidity coefficient, and Luce’s shape factor. Radial and volumetric shrinkage decreased by 29.47% and 31.01%, respectively, toward the top, while shear strength dropped by 47.20%. In contrast, basic relative density, modulus of rupture, modulus of elasticity, and compression strength showed no significant variation along the culm. These findings highlight that G. apus is suitable for diverse applications including furniture, handicrafts, construction, engineered bamboo, and biomass products.

Shaofeng Jia, Yuchen Xu, Jun Lin et al.

With the continued advancement of deep electrification across various industries, the demand for higher power density in electric machines is steadily increasing. However, realizing high power density remains a significant technical challenge and has become a major bottleneck in machine development. The design of such machines is inherently constrained by the strong coupling among electromagnetic (EM), thermal, and mechanical domains, while systematic analyses of these challenges remain insufficient. This paper clarifies the interdependent relationships among these domains during the machine design process. It reviews key enabling strategies, including machine design based on advanced electromagnetic theory, innovative thermal management techniques, cutting-edge material advancements, and state-of-the-art manufacturing technologies, that collectively enhance the performance and feasibility of high power density machines (HPDMs). The insights provided aim to support the development of next-generation machine systems with higher power density, compact size, and robust, sustainable performance across a wide range of industrial and technological applications.

Hengjie Qin, Lingling Chai, Haowei Yao et al.

Lemeshko Nikita V., Rubtsov Aleksey V., Shermatov Jamshed N. et al.

In the oil refining and petrochemical industries, the problem of premature failure of furnace equipment operating at high operating temperatures due to diffusion saturation of metal with structural elements with carbon is quite acute. Sections of coils of reaction furnaces operating under severe temperature conditions are especially often rejected due to carburization. The carbon saturation of the surface layers of the metal of the pipes to different depths leads to a change in the chemical composition and mechanical properties, and as a result, to a significant deterioration in plasticity, which increases the tendency to crack. One of the most significant causes of carburization of the metal of furnace tubes is coco-deposition along the inner surface of the tubes and this leads to a more intensive rotation of the mechanism of diffusion of carbon into the metal from coke. The rate and degree of carburization can be reduced or in some cases even prevented from forming surface modified silicon-based layers since it is silicon that is a carbon antagonist. In this regard, the current topic is the study of the features of silicon saturation of the surface layer of samples of austenitic pipe steel with different operating time.

Sourabh Shukla, Santosh Jaju, Sachin Untawale et al.

In this study, the effect of corrosion and wear behaviour of Cr-Mn steel on fine grains were investigated. The sample were solution annealed (SA) for 1 h at 1050 °C and then cold rolled (CW) to 30%. Further the cold rolled sample were thermally aged (CW + TA) 900 °C for four hours. The findings showed that under the 10 N applied load, wear resistance increased with an increase in hardness and martensite fraction of the cold worked (CW) samples. However, the Cr-Mn steel had the superior wear resistance after thermal ageing (TA). In microstructural examination deformation bands can also be visible in cold work samples. The analysis implies that the γ -phase is apparent across all peaks within the spectra of SA samples. In instances involving 30% cold work, prominent α ′ martensite peaks were observed, accompanied by minimal ε -martensite peaks. Electrochemical impedance spectroscopy (EIS) analysis discloses a reduction in impedance and a concurrent increase in the defect density of the passive film. The CW+TA structure with good inclusive performances created an early constant hardened layer, which didn’t delaminate and peel off prematurely, thereby effectively increasing the wear resistance, according to analysis of the wear mechanism. The results also concluded that the corrosion resistance of CW sample decreases due to SIM formation, however CW+TA sample provide better corrosion resistance due to smaller and refined grain size.

R. Sandeep, A. Natarajan

In the twenty-first century, the application of carbon fiber reinforced polymer (CFRP) materials in the vehicle industry are growing rapidly due to lightweight, high specific strength, and elasticity. In the automobile and aerospace industries, CFRP needs to be joined with metals to build complete structures. The demand for hybrid structures has prompted research into the combination of CFRP and metals in manufacturing. Aluminium and CFRP structures combine the mechanical properties of aluminium with the superior physical and chemical properties of CFRP. However, joining dissimilar materials is often challenging to achieve. Various joining technologies are developed to produce hybrid joints of CFRP, and aluminium alloys include conventional adhesives, mechanical and thermal joining technologies. In this review article, an extensive review was carried out on the thermal joining technologies include laser welding, friction-based welding technologies, ultrasonic welding, and induction welding processes. The article primarily focused on the current knowledge and process development of these technologies in fabricating dissimilar aluminium and CFRP structures. Besides, according to Industry 4.0 requirements, additive manufacturing-based techniques to fabricate hybrid structures are presented. Finally, this article also addressed the various improvements for the future development of these joining technologies. Ultrasonic welding yields the maximum shear strength among the various hybrid joining technologies due to lower heat input. On the other hand, laser welding produces higher heat input, which deteriorates the mechanical performance of the hybrid joints. Surface pretreatments on material surfaces prior to joining showed a significant effect on joint shear strength. Surface modification using anodizing is considered an optimal method to improve wettability, increasing mechanical interlocking phenomena.

BRAD Raluca

The paper analyses the transition from a linear economy paradigm to a circular economy model in the textile industry, which is one of the most polluting industries in the world. The linear model involves a large consumption of raw materials and generates waste, while the circular economy model focuses on the regeneration of raw materials and recycling. This includes the 5 R's of textile waste management: rethink, reduce, reuse, recycle, and reintroduce. The circular economy is characterized by close cycles, in which waste is minimized or converted into valuable inputs. Textile recycling process can be mechanical, thermal, chemical and biological. A series of recycling methods for different fiber-based materials: cotton, wool, synthetic, which are proposed in scientific papers is presented, contributing to the promotion of a zero-waste world.

Kevin Vega-Rojas Jhonatan, Samuel Andrade-Miranda Kevin, Justiniano-Medina Albert et al.

Today, robotics has made remarkable advances in a number of industries, including the food and beverage sector. One area of particular interest is the development of an automated bartender capable of efficiently preparing cocktails and drinks. In this context, a state-of-the-art robotic bartender has been designed and implemented following the VDI 2206 methodology, developed by the Association of German Engineers (VDI). This methodology has allowed a more precise definition of the product and accurate estimations in all phases of the mechanical, electrical, and electronic design, and for the mechanical design of the robotic bartender, it prioritizes a solid and safe structure to support the weight of the bottles and components while focusing on an attractive design to improve the user experience. The system features precise sensors to detect and measure ingredients and intelligent control algorithms to ensure accurate dosing. The user interface is intuitive, allowing for uncomplicated cocktail selection and drink customization, and Proteus software was used for the electrical and electronic design, which facilitated extensive simulation and debugging. The system incorporates a PIC16F877A microcontroller to manage and coordinate various functions such as sensors, actuators, and communications. Finally, the pilot implementation has demonstrated the system's effectiveness in preparing a wide variety of cocktails with reduced preparation time. The robotic bartender can produce 10–12 cocktails every 10 minutes, which improves the productivity of the establishments and benefits both bartenders and customers.

Yudong Wang, Nengneng Xu, Xiao-Dong Zhou

In electrochemically active systems, such as fuel cells, electrolyzers, and batteries, researchers often modify the material chemistry or operating variables at one of the electrodes (e.g., the cathode) to investigate its properties. This approach assumes that changes in measured polarization and cell performance result solely from the modifications made to the selected electrode, while the conditions at the other electrode (e.g., the anode) remain constant. However, the potential interactions between the polarizations of these two electrodes have remained unclear. In our study, we utilize a voltage probe capable of precisely determining electrode polarization. Our findings reveal three key insights: 1. The quantification of electrode polarization becomes feasible through the implementation of a voltage probe. 2. The fuel electrode plays a pivotal role in the performance of state-of-the-art solid oxide cells, with its influence being comparable to that of the oxygen electrode. 3. A reciprocal interaction exists between the two electrodes within a solid oxide cell. Consequently, when there are changes in the chemistry or operational conditions at one electrode, the polarization of the other electrode changes simultaneously.

Ahmad Hamdan, Ahmed Al-Salaymeh, Issah M. AlHamad et al.

Abstract This work is executed to predict the variation in global temperature and greenhouse gas (GHG) emissions resulting from climate change and global warming, taking into consideration the natural climate cycle. A mathematical model was developed using a Recurrent Neural Network (RNN) with Long–Short-Term Memory (LSTM) model. Data sets of global temperature were collected from 800,000 BC to 1950 AD from the National Oceanic and Atmospheric Administration (NOAA). Furthermore, another data set was obtained from The National Aeronautics and Space Administration (NASA) climate website. This contained records from 1880 to 2019 of global temperature and carbon dioxide levels. Curve fitting techniques, employing Sin, Exponential, and Fourier Series functions, were utilized to reconstruct both NOAA and NASA data sets, unifying them on a consistent time scale and expanding data size by representing the same information over smaller periods. The fitting quality, assessed using the R-squared measure, ensured a thorough process enhancing the model's accuracy and providing a more precise representation of historical climate data. Subsequently, the time-series data were converted into a supervised format for effective use with the LSTM model for prediction purposes. Augmented by the Mean Squared Error (MSE) as the analyzed loss function, normalization techniques, and refined data representation from curve fitting the LSTM model revealed a sharp increase in global temperature, reaching a temperature rise of 4.8 °C by 2100. Moreover, carbon dioxide concentrations will continue to boom, attaining a value of 713 ppm in 2100. In addition, the findings indicated that the RNN algorithm (LSTM model) provided higher accuracy and reliable forecasting results as the prediction outputs were closer to the international climate models and were found to be in good agreement. This study contributes valuable insights into the trajectory of global temperature and GHG emissions, emphasizing the potential of LSTM models in climate prediction.

Yiying Zhang, Wei Hou

I was invited to make a brief commentary on a recent article titled “Determining Spatially Varying Profit‐Maximizing Management Practices for Miscanthus and Switchgrass Production in the Rainfed United States” published in GCBB by Zhang et al. (2022). In the work, they propose management practices to maximize profitability through economically optimal N fertilizer application, temporal and spatial variation, and optimal age rotation of two energy crops. This interesting and thoroughly investigated result would be instructive for the applications of perennial energy crops.

H. Sreenivas, N. Krishnamurthy, G. Arpitha

Abstract Natural fibers have been used since the dawn of civilization. Customer demand for sustainable products and advances in technology has increased due to which the utilization of natural fibers are playing vital role in application of aerospace, automobile, marine industries etc., whereas natural fibers are extensively used in automotive industries and aerospace applications. Good amount of research has been directed on natural fibers and related composites to find mechanical, thermal and physical characteristics. Amongst variety of available natural fibers like bamboo, sisal, cotton, jute, kenaf, coir, industrial hemp, banana etc., kenaf fibers has been used exclusively in hybrid composites because of its enhancing mechanical properties. Therefore, this paper gives an overview on development of kenaf based composite by considering various factors like, stacking sequence (layer by layer), volume ratio of fibers to matrix, angular orientation of fibers and chemical modification of fiber surface to enhance adhesion of fiber to matrix etc., the mechanical properties and various application of kenaf hybrid composite. Several issues related to enhancing the properties of composite are also discussed in order to get sustainable hybrid composite.

Y. Yagcı, B. Kiskan, N. Ghosh

Y. Shin, W. Lee, Hansang Kim

Abstract In recent years, the demand for composite materials in various industries such as aerospace, defense, and automotive industries has increased significantly. Furthermore, the mechanical properties of carbon fiber-reinforced plastic (CFRP) composites have been improved significantly. However, the out-of-plane (thickness direction) mechanical properties of CFRP laminates are considerably inferior to their in-plane mechanical properties. Owing to their unique properties, carbon nanotubes (CNTs) have been used to improve the mechanical properties of CFRP composites. However, it is challenging to disperse high concentrations of CNTs in the polymer resin matrices of such composites. In this study, a high concentration of CNTs was incorporated in CFRP laminates in the form of CNT/epoxy films by using ultrasonication and three-roll milling. Furthermore, unidirectional and plain woven prepregs were used for reinforcement. The mode II interlaminar fracture toughnesses of the CNT/epoxy film-interleaved CFRP composites with different CNT concentrations were measured by carrying out their end-notched flexure (ENF) tests. Optical micrographs were obtained to observe the microstructures of the specimens with different CNT loadings. The fracture surfaces obtained after the ENF tests were examined using a scanning electron microscope to investigate the toughening mechanism of the composites.

R. Thakur, K. K. K. Singh