International Journal of Mechanical and Materials Engineering最新文献

{"title":"Nanoscale engineering of multi-component ZnO varistors: advanced computational modeling and energy absorption optimization","authors":"Arash Vaghef-Koodehi","doi":"10.1186/s40712-025-00364-y","DOIUrl":"10.1186/s40712-025-00364-y","url":null,"abstract":"<div><p>This study presents a comprehensive computational framework for optimizing energy absorption in nano-engineered zinc oxide varistors through systematic multi-component design. A nine-component varistor system comprising ZnO (96.5 mol%), Bi₂O₃ (1.2%), Sb₂O₃ (0.8%), NiO (0.4%), Ce₂O₃ (0.3%), ZrO₂ (0.25%), SnO₂ (0.2%), Co₃O₄ (0.2%), and SiO₂ (0.15%) was computationally modeled using COMSOL Multiphysics to investigate nanoscale energy dissipation mechanisms. The optimized composition demonstrates exceptional nonlinearity coefficient (α = 48) and energy absorption capacity (195 J cm⁻³), representing 40% enhancement over conventional microstructured designs. Finite element analysis reveals critical electric field concentrations at grain boundaries reaching 6.2 kV cm⁻¹ with current density variations of 18 × between conducting pathways and matrix regions. Multi-physics simulations incorporating coupled electromagnetic-thermal analysis demonstrate superior thermal stability with peak temperature gradients of 15°C mm⁻¹ and recovery time constants of 8.2 s. The computational framework provides unprecedented insights into nanoscale conduction mechanisms, enabling precise optimization of varistor compositions for enhanced surge protection applications.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00364-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145561163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal, structural, and morphological features of Zea mays husk activated carbon for low pressure hydrogen physisorption","authors":"O. P. Gbenebor,&nbsp;A. P. I. Popoola","doi":"10.1186/s40712-025-00348-y","DOIUrl":"10.1186/s40712-025-00348-y","url":null,"abstract":"<div><p>Plant-sourced biomass is a natural, renewable material that has proven to be a good substitute for fossil fuels in energy. Activated carbon (AC) is a carbonized porous material often synthesized from plant biomass for different energy applications, including hydrogen storage. Considering the components of the corn stover, the potency of corn husk (CH) AC for hydrogen storage via physisorption needs to be evaluated. Two different conventional activation reagents, potassium hydroxide (KOH) and sodium hydroxide (NaOH), are made to interact with carbonized corn husk biochar. Characterizations through scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectroscopy, and thermogravimetric analysis (TGA) show that the properties of these two ACs are comparable. However, their porous structures as analyzed via Brunauer–Emmett–Teller (BET) technique clarify the difference, as activation with KOH (AKNH) possesses a higher microporous surface area (S_BET) and volume of 904.76 m²/g and 1.00 cm³/g, respectively; 704.80 m²/g and 0.36 cm³/g are characterized by NaOH-activated CH biochar (ANCH). At 77 K and 1.2 bar, 2.84 wt.% hydrogen is adsorbed by AKCH, while the uptake capacity for ANCH is 1.48 wt.%. The higher S_BET and micropore volume displayed by AKCH are attributed to its better hydrogen uptake.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00348-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145511043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On-chip catalytic combustion of hydrogen using Pt and Ru quantum-crystallites on functionalized SiO2 aerogels","authors":"Ana Luiza Silveira Fiates,&nbsp;Oliver Thüringer,&nbsp;Andreas Schander,&nbsp;Raphaell Moreira,&nbsp;Marco Schowalter,&nbsp;Wilke Dononelli,&nbsp;Konrad Krämer,&nbsp;Andreas Rosenauer,&nbsp;Thorsten M. Gesing,&nbsp;Michael J. Vellekoop","doi":"10.1186/s40712-025-00340-6","DOIUrl":"10.1186/s40712-025-00340-6","url":null,"abstract":"<div><p>Hydrogen offers a high-energy, carbon-free fuel alternative; however, conventional flame-based hydrogen combustion poses challenges, including NO_x emissions and the risk of flame flashback. Catalytic combustion provides a safer, low-temperature approach to hydrogen utilization, but realizing it within compact, integrated systems have remained a significant challenge. This study introduces an innovative approach to hydrogen catalytic combustion by directly integrating noble metal single quantum-crystallites of Pt and Ru within a porous silica aerogel matrix embedded in a silicon chip. This configuration enables deep nanoparticle (<i>np</i>) penetration throughout the aerogel network, maximizing the catalytic surface area and providing efficient on-chip hydrogen combustion. The <i>np</i>@aerogel systems are systematically synthesized and incorporated within silicon chips equipped with a polyimide membrane and Pt thermal structures. This unique setup allows for direct, real-time characterization of hydrogen catalytic combustion by measuring resistance changes in an embedded thermistor. The Pt@SiO₂ system demonstrates a rapid and substantial temperature increase of up to 40 K upon hydrogen exposure, independent of both preheating and Pt concentration, underscoring its robustness and adaptability for micro-scale hydrogen combustion. This on-chip integration of <i>np</i>@aerogel catalysts marks a significant advancement for hydrogen-based energy applications, offering a compact, scalable platform for efficient catalytic combustion. This approach opens pathways for applications in thermoelectric generators and other micro-reactor technologies where controlled, localized energy generation is critical.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00340-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145511044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polycarbonate nanocomposite thin films for EMI shielding: influence of CeNiO3 and graphene nanoplatelets","authors":"Supreetha M.,&nbsp;Veena M.G.,&nbsp;Madhukar B.S.,&nbsp;Pawandeep Kaur,&nbsp;Gnana Prakash A.P.","doi":"10.1186/s40712-025-00361-1","DOIUrl":"10.1186/s40712-025-00361-1","url":null,"abstract":"<div><p>Polycarbonate (PC)-based nanocomposites reinforced with cerium nickelate (CeNiO₃) and graphene nanoplatelets (GNP) were synthesized for enhanced electromagnetic interference (EMI) shielding applications. Morphological analysis through SEM and EDX confirmed uniform dispersion and elemental composition of the nanofillers. The structural and chemical interactions were validated using XRD and FTIR, indicating successful integration of CeNiO₃ and GNP into the polymer matrix. The AC conductivity, dielectric loss tangent, and magnetic loss tangent increased with higher filler loading, promoting effective energy dissipation. Among all compositions, the PC/4wt% CeNiO₃@ 6wt% GNP nanocomposite exhibited the highest shielding effectiveness of 36.32 dB in the X-band (8.2–12.4 GHz), attributed to a synergistic balance between reflection and absorption mechanisms. The results of this study highlight the capabilities of CeNiO₃-GNP hybrid fillers in producing high-performance materials for electromagnetic interference shielding in cutting-edge electronic applications.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00361-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145511042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Grain refinement in extruded A6063 Al alloy using additively manufactured billets","authors":"Shogo Oda,&nbsp;Akihiko Chiba,&nbsp;Shun-Ichiro Tanaka","doi":"10.1186/s40712-025-00356-y","DOIUrl":"10.1186/s40712-025-00356-y","url":null,"abstract":"<div><p>In this study, we developed a new process for grain refinement in the A6063 aluminum alloy using extrusion with aluminum billets fabricated by additive manufacturing. The resultant extruded profile exhibited fine grains with an average diameter of 3 μm and displayed a fibrous structure elongated in the extrusion direction. The internal microstructure exhibited the typical texture of a plate-shaped extruded profile, characterized by &lt; 001 &gt; + β-fiber{110} &lt; 112 &gt; . The results obtained using this method were superior to those obtained using the conventional approach, in which cast billets were used for A6063 extruded profiles. Specifically, the tensile strength and elongation values improved by 10% and 40%, respectively. Additionally, we detected the development of a yield point (which is generally not observed in aluminum alloys). This outcome confirmed that uniform fine grains were successfully obtained using this process. In addition, this method facilitated the production of extruded profiles, with complex cross-sectional shapes and fine grains, in an alloy with a low transition-metal concentration, such as the A6063 alloy (whose manufacturing has hitherto remained challenging).</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00356-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145511021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced photocatalytic and antibacterial performance of ZnO/CuO nanocomposites via carbon dot decoration","authors":"Michael Asfaw Ameya,&nbsp;Negesa Bogala Bekela,&nbsp;Jabesa Negasa Guyasa,&nbsp;Kai Zhu,&nbsp;Tamene Tadesse Beyene","doi":"10.1186/s40712-025-00350-4","DOIUrl":"10.1186/s40712-025-00350-4","url":null,"abstract":"<div><p>Zinc oxide nanoparticles (ZnO-NPs) are gaining popularity due to their low toxicity, cost-effective production, and environmentally friendly profile. However, their practical use is limited by inherent challenges such as a large energy bandgap, high exciton binding energy, rapid electron–hole recombination, poor absorption of visible light, and low photocatalytic efficiency. To address these issues, our study introduces an innovative approach: incorporating small amounts of transition metal oxides like copper (II) oxide (CuO) along with trace amounts of carbon nanomaterials, specifically carbon dots (C-dots). We demonstrate that adding just 9% CuO nanoparticles and 2% C-dots to ZnO-NPs significantly enhances their properties. This modification reduces the energy bandgap from 3.08 eV to 2.51 eV, improving visible light absorption and boosting photocatalytic activity. In practical application, the optimized composite achieved an impressive 98.7% removal of methylene blue (MB) dye within 60 min under visible light, far surpassing pure ZnO-NPs, which only removed 62% in the same period. Additionally, the modified nanocomposites exhibit markedly improved antibacterial activity. The zones of inhibition against bacteria such as Bacillus Seraus, Escherichia coli, Salmonella typhi, and Staphylococcus aureus increased significantly from 8–13 mm for pure ZnO-NPs to 14–18 mm for the ZnO/CuO@C-dot composites, indicating stronger antimicrobial effects driven by enhanced surface charge and stability. Overall, our findings reveal that even minimal integration of C-dots into ZnO/CuO nanocomposites can dramatically elevate their photocatalytic and antibacterial performance. To our knowledge, this represents one of the most significant improvements achieved through such small additive modifications, opening new avenues for efficient environmental remediation and biomedical applications.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00350-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining dielectric constant improvement techniques for ferroelectric applications using PVDF-HFP/TFO composite films","authors":"Ramakant M. Choudhari,&nbsp;Nitin A. Kharche,&nbsp;Santosh R. Shekokar,&nbsp;Yugesh A. Kharche,&nbsp;Dipak P. Kharat,&nbsp;Sachin H. Choudhari,&nbsp;Nithesh Bhaskar N,&nbsp;Mohan Kumar G R,&nbsp;C. Durga Prasad,&nbsp;H. V. Moulya,&nbsp;C. Hemanth Kumar,&nbsp;Adem Abdirkadir Aden","doi":"10.1186/s40712-025-00360-2","DOIUrl":"10.1186/s40712-025-00360-2","url":null,"abstract":"<div><p>The current research focuses on the fabrication of polymer-ceramic composite materials by the solution casting process of multi-faceted titanium ferrite, TiFe₂O₄ (TFO). We experimented with different proportions of TFO composition, ranging from 5 to 15 wt%, in the polymer matrix of PVDF. Various characterization methods were employed to study the mechanical, spectroscopic, morphological, and dielectric properties affected by TFO load. X-ray diffraction (XRD) was used to identify both non-polar alpha- and polar beta-phases in the composites. Samples from scanning electron microscopy (SEM) revealed a spherulite-like morphology and uniform distribution of TFO particles. Our main goal was to increase the ferroelectric properties of the polyvinyl-HFP by increasing the percentage of TFO filler to increase the β-fraction. The enhanced attributes of our materials hint at potential applications in polymer-ceramic capacitor technology, a topic we delve into extensively.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00360-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of chemical, physical and mechanical properties of raw fiber from the bark of Grewia ferruginea plant","authors":"Getaw Ayay Tefera,&nbsp;Ermias Gebrekidan Koricho,&nbsp;Mesfin Kebede Kassa","doi":"10.1186/s40712-025-00351-3","DOIUrl":"10.1186/s40712-025-00351-3","url":null,"abstract":"<div><p>Cellulosic natural fibers play an important role as reinforcement in polymer composites due to their biodegradability, lightweight and non-toxicity. <i>Grewia ferruginea</i> (GF) <i>fiber</i> is a type of natural fiber containing cellulosic fiber that is inexpensive and readily available in sub-Saharan Africa. In this study, the GF <i>fibers</i> collected from Central Ethiopia were extracted and its physical, chemical and mechanical properties such as density, diameter, cellulose, hemicellulose, lignin, tenacity and tensile strength were experimentally characterized. The findings reveal that the raw GF fiber exhibited a mean fineness of 90.55 Tex, an average cross-sectional area of 0.0096 mm², and density values of 1.43 g/cm³ at 20 °C. Chemical analysis indicates the GF fiber contains 2.413% extractive,65.6% cellulose, 13.25% hemicellulose, and 18.74% lignin. It was observed that the raw GF fiber exhibits a relatively high cellulose content compared to most plant fibers and demonstrated GF suitable for applications that demand strength and durability. A tensile strength of 309.3 MPa was recorded for the raw GF fiber. Based on these results, it can be concluded that this study has briefly demonstrated that raw GF fiber is positioned as a viable and sustainable alternative to other natural fiber for composite reinforcement, with properties that can be further improved through fiber treatment optimization.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00351-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of baking on mechanical properties of 5182 aluminum/DP 780 steel spot welding joints","authors":"Sai Zhang,&nbsp;Xuan Shi,&nbsp;Tao Li,&nbsp;Xian-Ming Meng,&nbsp;Cong-Qian Cheng,&nbsp;Xiao-Zhong Wu,&nbsp;Tie-Shan Cao,&nbsp;Jie Zhao","doi":"10.1186/s40712-025-00325-5","DOIUrl":"10.1186/s40712-025-00325-5","url":null,"abstract":"<div><p>Using traditional resistance spot welding with a novel bulged double-helix electrode, 5182 aluminum alloy and DP780 galvanized steel were welded under two different current parameters. After baking, both samples exhibited a similar average peak load of 3.30 kN, while defect locations showed significant differences. In the low-current sample, defects remained near the nugget center (11.64 μm), whereas in the high-current sample, defects shifted farther away (1490.3 μm). Crack initiation in both cases started along interfacial compounds at the weld edge. In the low-current sample, the crack propagated along interfacial defects on the aluminum side until complete fracture. In contrast, the high-current sample exhibited crack deflection into the aluminum, leading to a pullout fracture. The findings highlight the influence of post-welding baking on the durability and performance of welded joints. This study provides valuable insights for optimizing aluminum-steel resistance spot welding in industrial applications, particularly for reliability after baking.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00325-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance enhancement of supercapacitors using zinc oxide/reduced graphene oxide nanocomposites and Nafion-117 based hybrid electrolytes","authors":"Santi Rattanaveeranon,&nbsp;Knavoot Jiamwattanapong,&nbsp;Rudeerat Suntako","doi":"10.1186/s40712-025-00354-0","DOIUrl":"10.1186/s40712-025-00354-0","url":null,"abstract":"<div><p>This study presents a cost-effective strategy to enhance supercapacitor performance using ZnO/reduced graphene oxide (ZnO/rGO) nanocomposites synthesized via a microwave-assisted method. The nanocomposites exhibit pseudocapacitive behavior, enabling improved charge storage. A PVA/KOH gel polymer electrolyte and a Nafion-117 film were integrated to enhance ionic conductivity and structural stability. Structural and morphological characterizations (XRD, FTIR, SEM, and TGA) confirmed the successful formation of uniformly distributed ZnO nanoparticles (average size: 22.44 ± 0.09 nm) on rGO sheets. Electrochemical testing revealed a high specific capacitance of 812.23 F·g⁻¹, an energy density of 28.20 Wh·kg⁻¹, and a power density of 4,060.80 W·kg⁻¹. Moreover, the composite retained 99.97% of its capacitance after 5,000 cycles. These results demonstrate the potential of ZnO/rGO–Nafion hybrid electrodes for next-generation high-performance supercapacitors.</p></div>","PeriodicalId":592,"journal":{"name":"International Journal of Mechanical and Materials Engineering","volume":"20 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://jmsg.springeropen.com/counter/pdf/10.1186/s40712-025-00354-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}