Hasil untuk "Mechanical industries"

Ganugapenta Ramesh, Anantha Chakravarthy V.V., Hemadri Ch. et al.

Stainless steel 32750 (SS32750) is a duplex stainless steel renowned for its exceptional corrosion resistance and mechanical properties, making it ideal for demanding applications, particularly in harsh environments such as offshore and marine industries. This study examines the microstructure and mechanical properties of SS32750 weldments produced using two distinct welding techniques: Gas Tungsten Arc Welding (GTAW) and Laser Welding. The investigation focuses on the effect of various welding parameters, including heat input, welding speed, and shielding gas composition, on the resulting microstructure. Mechanical properties such as tensile strength, surface roughness, distortion, and weld integrity were evaluated using methods like tensile load testing, X-ray radiography, and wire-cut EDM. The study provides critical insights into the relationship between welding techniques, process parameters, and the resulting performance of SS32750 weldments.

Linda Sandgren, Sri Ram Gnanesh, Erik Johansson et al.

Copper is a strategic raw material and an important component in electric motors, widely used across industries because of its excellent conductivity and recyclability. It plays an important role in the transformation from fossil fuel-based systems to green, electrified systems. However, substantial material losses continue throughout the lifecycle of electric motors, even with copper’s intrinsic capacity for circularity. Also, copper’s increasing demand, which is driven by the emergence of electric vehicles, industrial electrification, and renewable energy infrastructure, poses questions regarding its sustainable supply. The recovery of secondary copper sources from end-of-life (EoL) products is becoming more and more important in this context. However, it is still difficult to achieve circularity of copper, especially from industrial electric motors. This study investigates the challenges of closing the loop for copper during the lifecycle of motors in industrial applications. Based on an examination of EoL strategies, material flow insights, and practical investigation, the research pinpoints significant inefficiencies in the current processes. The widespread use of scraping as an approach of end-of-life management is one significant issue. Most of the electric motors are not built to separate their components, which makes both mechanical and manual disassembly difficult. The quality of recovered copper is thus compromised by the dominance of mixed metal shredding methods in the recycling step. This study highlights the need for systemic changes in addition to technical solutions to address copper circularity issues. It requires a focus on circularity in designing, giving disassembly and metal recovery a priority. This study focuses on circularity and its technological challenges in a value chain of copper. It not only identifies different processes such as supply chain disconnections and design constraints, but it also suggests workable solutions to close the copper flow loop in the electric motor sector. Copper quality and recovery is ultimately a problem involving design, technology, and cooperation, in addition to resources. This study supports the transition to a more sustainable and circular electric motor industry by offering a basis for directing such changes in industry practices and prospective EU regulations.

Naoki Matsuo, Kiyoto Tanabe

As economies move toward carbon neutrality, hydrogen produced from zero-carbon electricity and synthetic fuels derived from captured carbon dioxide (CO₂) and such hydrogen—hereafter referred to as carbon capture and utilisation (CCU) fuels—are expected to play a complementary role to electrification, particularly in hard-to-abate sectors. Despite their potential, market uptake of CCU fuels would remain limited, if we keep accounting and regulatory frameworks that fail to translate their climate value into economic incentives for fuel users, as well as their technological and economic immaturity. This paper examines CCU fuels through the lens of energy and climate policy rule design, focusing on the attribution of greenhouse gas (GHG) emissions and emission reductions across value chains and national borders. It reviews existing and emerging international and national schemes, including those developed by the Intergovernmental Panel on Climate Change, International Organisation for Standardisation, the EU and Japan, and identifies structural inconsistencies between conventional point-of-emission accounting and the economic characteristics of CCU fuels. The central contribution of this study is to demonstrate that user-side incentives would be enhanced or neutralised depending on near-future rules governing CO2 emission attribution, and to propose an attribution framework that promotes the consumption of CCU fuels and thereby induces greater investment in their production without undermining environmental integrity. The paper proposes treating CCU fuels as having a zero-emission factor at the point of use, combined with a simplified upstream accounting rule in which captured CO₂ used for CCU synthesis is not counted as CO2 removal or emission reduction. It then evaluates 3 policy implementation pathways—national GHG inventory rules linked to Nationally Determined Contributions (NDCs), domestic regulatory schemes, and international transfers via Internationally Transferred Mitigation Outcomes—highlighting their respective implications for market formation and cross-border trade. Key technical requirements, including certification of CCU fuel origin and baseline definitions, are also discussed. By explicitly linking accounting rules to economic incentives, this study provides a policy-relevant framework for harmonised rule-making that can facilitate investment, international trade, and the scalable deployment of CCU fuels in global decarbonisation strategies.

Suswanth Poluru, Aarjoo Jaimin, Nitin R. Kotkunde et al.

The mechanical response of 92 W-5Co-3Ni alloy was analysed at dynamic strain rates ranging from 1800 s−1 to 4200 s−1 and temperatures from 323 K to 873 K. The marginal strain hardening, followed by significant strain softening, was seen in flow stress behaviour. The rise in the yield strength at room temperature and higher strain rates was mainly due to the increased fraction of low-angle grain boundaries and kernel average misorientation. The severe elongation of tungsten grains was noticed for all strain rates. The Adiabatic Shear Bands (ASBs) were noticed above strain rates of 2700 s−1 with an average shear band’s width of 45 µm. Moreover, the average size of the ASB shear band’s width was reduced to 30 µm for higher strain rates (4200 s−1), which exhibited the enhancement of the self-sharpening capacity of the kinetic energy penetrator. Subsequently, the Arrhenius constitutive model and machine-learning-based Random Forest model (RF) were developed to predict flow stress. The Arrhenius model accurately predicted the flow stress behaviour with a correlation coefficient (R) of 0.9766 and an average absolute error (AARE) of 2.033 %. However, the RF model demonstrated the best prediction of flow stress behaviour with an R of 0.9912 and an AARE of 1.145 %.

Ivana Castello, Andrea Baglieri, Enzo Montoneri et al.

ABSTRACT A crucial point for the ecological transition toward a circular bioeconomy is represented by the utilization of municipal biowaste for novel uses in agriculture. Thus, in vitro and in vivo performance of oxidized biopolymers (Ox BPs) obtained from the organic fraction of municipal waste was evaluated against Rhizoctonia root rot and southern blight of tomato (Solanum lycopersicum L.). Further, the selectivity of these biopolymers was evaluated on young tomato seedlings. Effects of Ox BPs were tested at 100, 1000, and 5000 μg mL−1 in reducing Rhizoctonia solani and Sclerotium rolfsii mycelial growth and decreasing relative infections in tomato. The effective concentrations able to reduce mycelial growth by 50% and 95% (EC50 and EC95) calculated according to logit models and minimum inhibitory concentrations (MIC) were about 434, 4550, and 5000 μg mL−1 for S. rolfsii, whereas it was possible to calculate only EC50 (about 788 μg mL−1) for R. solani. In regard to in vivo experiments, Ox BP at 5000 ppm achieved good reductions for both fungal infections ranging from about 62% up to almost 90%, whereas phytotoxic effects were not detected on tomato seedlings at the 3–4 and 4–5 true leaf stages. To the authors' knowledge, this is the first report about Ox BPs antifungal performance against globally widespread soilborne diseases of tomato without detrimental effects on the host crop. However, further studies are needed to confirm the data; this paper presents a starting point for both an eco‐friendly disease management approach and recycling of the organic fraction (organic C) of municipal biowastes within the circular bioeconomy framework in a self‐sustainable ecosystem.

Anna Krzak, Agnieszka J. Nowak, Jiri Frolec et al.

Glass-epoxy composites are a type of structural material widely used in the aerospace, automotive, wind energetics and construction industries. This study provides a thorough analysis of the mechanical, thermal and electrical properties of a glass-epoxy composite produced under industrial conditions, based on testing at room and cryogenic temperatures. The industrial-scale composite exhibited significantly lower thermal conductivity than the laboratory-prepared sample across the entire temperature range. We attribute this difference to qualitative or quantitative changes in the glass reinforcement. Cyclic loading tests showed only minor degradation of Young's modulus, with values increasing to ∼30–31 GPa under cryogenic conditions. The composite exhibited significant improvements in tensile strength (638 MPa, +54 %), flexural strength (1030 MPa, +87 %), and nearly doubled fracture toughness (42.2 MPa√m), while maintaining comparable impact resistance. These results highlight the excellent mechanical performance and reliability of the material at −196 °C, confirming its suitability for cryogenic applications. This study also evaluates the environmental impact of different composite material manufacturing processes via life cycle assessment (LCA) analysis. The findings suggest that, while the hydraulic press method offers excellent mechanical performance, it has the greatest environmental impact due to its high energy consumption, significant waste generation and contribution to climate change. These results contribute to the development of sustainable composite technologies and may serve as a foundation for further research or for comparing different materials to determine the most suitable option.

Alliance Gracia Bibili Nzengue, Khumbulani Mpofu, Ntombizodwa Ruth Mathe et al.

Selective laser melting (SLM) SLM has gained interest in processing lightweight metals like aluminium alloys. The SLM processing remains challenging in finding the appropriate process parameters for the desired mechanical properties. Previous studies have used energy density formulas and heat treatment to improve the mechanical properties of materials in different ways. However, the holistic approach to studying the physical and mechanical properties has less been reported. Therefore, this article presents the optimisation of the processing window of the AlSi12 aluminium alloy produced by the SLM process. The design of the experiment (DoE) was carried out using the Response Surface Methodology (RSM) implemented in the Design Expert 2018 environment. It involved two process factors in the following range of scan speed (500–2500 mm/s) and laser power (50–300 W). The combination of a scan speed of 500 mm/s and a laser power of 300 W resulted in a relative density of 97.4 %, an ultimate tensile strength (UTS) of 418 MPa and a hardness of 132.6 HV. The microstructure and fracture analysis provided evidence of reduced defects with the combination of parameters mentioned above. Thus, this study contributes to adding a new set of data to existing work for more comprehensive parameter calibration. This study helps industries that produce aluminium alloys from SLM processes obtain the optimal range of process parameters that produce parts with the desired mechanical properties.

Muntadher Hashim Abed, Hasan A. Al-Asadi, Ahmed Oleiwi et al.

The increasing desire for comfort and healthy indoor environment, as well as improvements in energy standards in recent years, have stressed the need to make an active use of the building mass to achieve the maximum energy saving This is why the application of ventilated hollow-core slab systems (VHCS) can be considered as one of the innovative approaches. These systems have precast concrete slabs with tubular voids directing ventilation air on its length. In the present study Solving this system numerically using the ANSYS fluent program to study the temperature distribution and air flow in the 3-D test model of the present study to determine the feasibility of applying this system in an arid climate especially in Iraq by checking the inlet velocity and temperature and to predict the impact of these operating parameters on human comfort and energy savings. The study aimed to provide a numerical analysis of a conditioned zone's temperature distribution using VHCS. The investigation was carried out on a scale model room of size (1 m × 1.2 m × 1 m) with a scale factor of ¼. Four distinct scenarios were examined: the first two cases occurred during a no-load time in the night when there were no internal or external loads and examined the effects of changes in inlet temperatures and air velocities. The remaining two scenarios were conducted during an occupied period with internal heat gain of 630 W/m2 and external heat gain of 800 W/m2 based on the SHGC for the summer season of Iraq. As previously demonstrated, setting the inlet velocity to 1 m/s resulted in an optimal temperature and velocity distribution in the main flow, irrespective of changes in the external and internal loads and temperatures of the supply core. The findings shown that input air velocity and temperature affect heat remove efficiency. In addition, numerical outcomes have also illustrated that the Thermal Active VHCS System, while used in combination with ventilation strategies, could indeed regulate the space conditions by cooling down the building's ceiling, thus eradicating stored heat. All investigations found VHCS systems suitable for air conditioning in dry and hot locations. The systems are known for their ease of use, simplicity, high performance, comfort, and energy savings. They can also reduce peak loads to boost structural energy efficiency.

Keiichi Tomishige, Masayoshi Honda, Hiroshi Sugimoto et al.

Abstract Catalytic hydrogenolysis systems of C-O bonds in furan ring, tetrahydrofuran ring and tetrahydropyran ring in biomass-derived cyclic compounds are reviewed. Furfural or its hydrogenation products (furfuryl alcohol and tetrahydrofurfuryl alcohol) have been frequently used as substrates for this type of reactions. Ring-opening of furfuryl alcohol over metal catalysts combined with basic components gives a mixture of 1,2-pentanediol, 1,5-pentanediol and other by-products. The selectivity much depends on catalysts and reaction conditions, and good 1,2-pentanediol selectivity can be obtained. For 1,5-pentanediol synthesis, more selective approaches have been reported such as Cu-zeolite catalysts for furfuryl alcohol hydrogenolysis in flow reactor and M-M’Ox-type (M: noble metal; M’: transition metal) supported catalysts or Ni-LnOx (Ln: rare earth element) catalysts for tetrahydrofurfuryl alcohol hydrogenolysis. The metal catalysts and M-M’Ox-type catalysts can be applied to ring-opening hydrogenolysis of other furan- and tetrahydrofuran-based compounds, respectively. Among the products of ring-opening hydrogenolysis of biomass-derived compounds, 1,5-pentanediol seems to be the most important because of the potential use as a monomer. The recent progress and reported properties of polymers using 1,5-pentanediol as a monomer are also summarized.

Madina Shayakhmetova, Amirzhan Kassenov, Gulmira Zhumadilova et al.

This article describes the design of a centrifuge for the separation of fat from meat–bone slurry to produce fat-extracted animal feed. The characteristics of the main components of the equipment and the principle of its operation were presented. The productivity of the centrifuge depending on duration and speed of rotation was determined. Data were provided for different drum speeds (1000, 1500, 2000, 2500 rpm) and centrifugation durations (5, 7, 10 and 15 min), with the yield (output) of defatted slurry measured as a percentage. Among the various conditions tested, the maximum yield of slurry was observed when the drum was rotated at 2000 rpm for 5 min, with a yield of 68.97%, while the lowest yield was observed when the drum was rotated at 1000 rpm for 15 min, with a yield of 55%. On the basis of modeling, a physical model including centrifugal separation with simultaneous centrifugal filtration was presented in the form of a system of differential, algebraic, and criterion equations.

Daniela Lazoroska

Abstract Background Since the 1960s, women’s social and political engagement in Japan has been closely tied to the roles of mothers and housewives. On the other hand, the country is undergoing considerable demographic changes and has come to be considered an aging society, where an increasing number of women are opting out of marriage and child-rearing. Drawing from qualitative research with women in managerial positions in solar energy communities, this article explores the complex maneuvers informants conducted to fulfill their goal: the expansion of renewable energy in Japan. Results The empirical findings point to a new, and underexplored perspective: of aging as a catalyzer for transgressing certain norms and expectations on female behavior in the context of grassroots mobilization. Aging tends to be axiomatically represented as a time of decline, and unidirectional consumption of communal resources. I examine how transitioning from life stages centered on careers and child-rearing offers resources that my informants draw on to sustain their engagement in solar energy communities. I further examine how my informants carefully, and paradoxically, navigate gendered expectations by actively appealing to dominant narratives on women: as attentive communicators attuned to the needs of others. Conclusions The article provides suggestions for further diversifying Japan’s community energy landscape, such as (a) increasing awareness of inequalities through open discussion on the topic; (b) gender-inclusive quotas on boards; (c) creating peer-mentoring networks; (d) stimulating a culture of dialogue open to dissensus; (e) shifting the focus away from women needing to make behavioral changes; and (f) not idealizing how much can be achieved without generating discomfort.

Nguyen Anh Tuan

In this article, new research on the multi-objective optimization of the process parameters applied to enhance the efficiency in the shoe-type centerless grinding operation for the inner ring raceway of the ball bearing made from SUJ2 alloy steel is presented. The four important input parameters for this process, which included the normal feed rate of fine grinding (S_nf), the speed of the workpiece (V_w), the cutting depth of fine grinding (a_f), and the number of ground parts (N_p), were investigated. The aim of the study was to find the most appropriate value set of process parameters in order to, simultaneously minimize the grindstone wear (G_w), maximize the material removal rate (MRR) and the total number of ground parts in a grinding cycle (N’p), while guaranteeing other technology requirements such as surface roughness Ra ≤ 0.5 (µm), oval level Op ≤ 3 (µm), etc. In order to solve the problem, based on the experimental data, in which the grindstone wear was measured online by a measuring system consisting of two pneumatic probes, the optimization of the target functions of G_w, N’p, and MRR and mathematical models that express the dependencies of outcome parameters G_w, Ra, Op, MRR, etc. on the process parameters were determined. Therefore, a global optimal solution of such a discrete and nonlinear multi-objective optimization problem was solved by using a genetic algorithm, presenting the most appropriate process parameters as follows: S_nf = 15.38 (µm/s), Vw = 6.00 (m/min), a_f = 11.76 (µm), and N_p = 20 (parts/cycle). In addition, the impact of the four process parameters (S_nf, V_w, a_f, N_p) on the wear of the grinding wheel (G_w), the oval level of parts (O_p), and the surface roughness of parts (Ra) was evaluated. The discovered technology mode has been applied to the real machining process for the inner ring raceway of the 6208_ball bearing made from SUJ2 alloy steel, and the outcome showed a much better result in comparison with default setting modes, while still ensuring the technology requirements. The difference between the predicted values and the real values of the parameters G_w, Ra, Op, and MRR were controlled within 5% of the ranges.

Bentao Xiong, Linfang Wei, Yifan Wang et al.

Abstract High cost of lignocellulases restricts the commercialization of biofuel and bio‐product production from lignocellulosic biomass. Constitutively expressed lignocellulases are considered to degrade cellulose to release small amount of soluble cellodextrins such as cellobiose for further large‐scale production of lignocellulases; however, the underlying mechanism remains to be elucidated. Here, a triple β‐glucosidase mutant of the model fungus Neurospora crassa, which prevents rapid turnover of cellobiose and thus allows the disaccharide to induce lignocellulases, was applied to perform parallel analyses of proteome and phosphoproteome changes in response to cellobiose and Avicel cellulose. The results revealed shared proteome and phosphoproteome responses to cellobiose and Avicel, corroborating the idea that cellobiose mediates the regulation of lignocellulase expression and secretion. The results further suggest that this regulation is achieved at multiple levels, including epigenetic, transcription, post‐transcription, translation, and post‐translation. Proteome profiling revealed that the proteins upregulated by cellobiose and Avicel were over‐represented in cellulose degradation and degradation product transport pathways. Phosphoproteome profiling revealed that the proteins differentially phosphorylated by cellobiose and Avicel were over‐represented by the pathways such as transcriptional control, protein processing and export, cell wall biogenesis, and cellular signaling. Deletion mutation analysis further suggests that the ER chaperon protein Hsp70‐6, the translocation complex subunit Sec66/Sec71, and the signal peptidase subunit Spc2 are involved in lignocellulase secretion, particularly translocation across the endoplasmic reticulum. Altogether, the results offer a new insight into how cellobiose mediates the regulation of lignocellulase expression and secretion, providing a potential strategy for the strain engineering to improve lignocellulase production.

Shinyoung Jeon, Changmin Son, Jangsik Yang et al.

Turbine generators operate with complex cooling systems due to the challenge in controlling the peak temperature of the stator bar caused by Ohm loss, which is unavoidable. Therefore, it is important to characterize and quantify the thermal performance of the cooling system. The focus of the present research is to investigate the heat transfer and pressure loss characteristics of a typical cooling system, the so-called stator ventilation duct. A real scale model was built at its operating conditions for the present study. The direction of cooling air was varied to consider its operation condition, so that there are: (1) outward flow; and (2) inward flow cases. In addition, the effect of (3) cross flow (inward with cross flow case) was also studied. The transient heat transfer method using thermochromic liquid crystals is implemented to measure full surface heat transfer distribution. A series of computational fluid dynamics (CFD) analyses were also conducted to support the observation from the experiment. For the outward flow case, the results suggest that the average Nusselt numbers of the 2nd and 3rd ducts are at maximum 100% and 30% higher, respectively, than the inward flow case. The trend was similar with the effect of cross flow. The CFD results were in good agreement with the experimental data.

Alok Kumar, Ramesh Garg, Dixit Garg

Managing risk in e-supply chain has become an essential field for researchers in this fast-growing market. Many researchers have contributed to this context for managing risks, but it remains uncertain. This study recommends a structural model to analyze the impact of various e-supply chain risk issues over demand risk. This model mainly covers seven categories of risk issues such as demand, organizational, infrastructure, etc. for this study which are related to mechanical manufacturing industries of Delhi region. So, after a detailed study and expert’s opinion, 38 Risks factors were included in this study to formulate the survey form or questionnaire. A questionnaire-based survey was conducted for gathering responses from 148 specialists belonging to mechanical manufacturing sector situated in Delhi region. This methodology consists of measurement and mathematical modeling. The technique is based on exploratory and confirmatory factor analysis using SPSS and AMOS software tool. Software tools like SPSS21 used for descriptive statistics and Amos Graphics 21 used for structural equation modeling. Risk related factors and sub-factors have been identified, assigned weight and prioritized in accordance with their importance using expert opinion through well-designed questionnaires. On the other hand, an empirical study was conducted for transforming a conceptual model into structural equation modeling. Structural identification and comparison of various risks related to the e-supply chain. Result finding proposes various e-supply risk issues which create significant positive (0.49) effect over demand risk. Result finding also suggests that sub-factors like Forecast Error and sudden cancellation of order are highly affected by e-supply risks.

Yair Zarmi, Jeffrey M. Gordon, Amit Mahulkar et al.

Summary: We present experimental results demonstrating that, relative to continuous illumination, an increase of a factor of 3–10 in the photon efficiency of algal photosynthesis is attainable via the judicious application of pulsed light for light intensities of practical interest (e.g., average-to-peak solar irradiance). We also propose a simple model that can account for all the measurements. The model (1) reflects the essential rate-limiting elements in bioproductivity, (2) incorporates the impact of photon arrival-time statistics, and (3) accounts for how the enhancement in photon efficiency depends on the timescales of light pulsing and photon flux density. The key is avoiding “clogging” of the photosynthetic pathway by properly timing the light-dark cycles experienced by algal cells. We show how this can be realized with pulsed light sources, or by producing pulsed-light effects from continuous illumination via turbulent mixing in dense algal cultures in thin photobioreactors.