University of Sistan and Baluchestan,
Iranian Society Of Mechanical EngineersChallenges in Nano and Micro Scale Science and Technology2821-000X14220260901Effect of Cadmium on Structure, Corrosion, and Magnetic Properties of Polymer–Spinel Ferrite Composite Coatings Deposited by EPD115984910.22111/cnmst.2026.55051.1292ENMortezaKhosraviDepartment of Materials Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, Iran.ShahriarSharafiDepartment of Materials Engineering and Metallurgy, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, IranAhmadIrannejadDepartment of Materials Engineering and Metallurgy, Faculty of Engineering, Shahid Bahonar University of Kerman, Kerman, IranJournal Article20260410High-entropy spinel ferrites (HESFs) have emerged as promising multifunctional materials due to their tunable magnetic and corrosion properties. In this study, composite coatings composed of six high-entropy spinel ferrite compositions and polyethyleneimine (PEI) were deposited on copper substrates via electrophoretic deposition (EPD). The effects of Cd incorporation and polymerization time (15 and 30 h at 180 °C) on microstructure, magnetic behavior, and corrosion performance were systematically investigated. Zeta potential values shifted from near-neutral (+1.57 to −0.94 mV) to more negative values (−6.81 to −10.46 mV) after 3 min under an electric field, indicating improved electrophoretic mobility. Uniform coatings were obtained under optimized conditions (200 V, 3 min, 2 g/L SDS). Increasing polymerization time enhanced coating cohesion but promoted crack growth, especially in Cd-containing samples.All coatings exhibited ferromagnetic behavior, although magnetic parameters decreased compared to powders due to polymer-induced dilution and reduced interparticle interactions. Electrochemical results showed that Cd incorporation reduced corrosion current density from 2.15 μA/cm² to as low as 0.1–0.5 μA/cm², indicating improved corrosion resistance. However, increasing polymerization time could increase icorr (e.g., from 0.1 to 5 μA/cm²) due to crack propagation. EIS analysis revealed a maximum total resistance of ~7544 Ω·cm², confirming enhanced corrosion protection under optimal conditions. Overall, coating performance is governed by the interplay between composition, polymerization, and microstructure, and optimal conditions are essential for achieving high-performance multifunctional coatings.https://chal.usb.ac.ir/article_9849_84523d7062e9990200b52a04bc0eb1ac.pdfUniversity of Sistan and Baluchestan,
Iranian Society Of Mechanical EngineersChallenges in Nano and Micro Scale Science and Technology2821-000X14220260901Investigation of Friction Factor and Nusselt Number Distributions for Zno-water Nanofluid under Forced, Mixed and Free Convection with Varying Eckert Numbers1630984810.22111/cnmst.2026.55029.1290ENTohidAdibiUniversity of BonabJournal Article20260405This study investigates the behavior of the friction factor and Nusselt number in fluid flow across forced, mixed, and free convection regimes, with a specific emphasis on the influence of the Eckert number. Numerical simulations were performed for a moving lid configuration, maintaining a constant Reynolds number (Re=100) while systematically varying the Grashof numbers (Gr=103,104,105) and Eckert numbers. The analysis reveals distinct trends: In forced (Gr=103) and mixed (Gr=104) convection, the mean friction factor remains largely constant across different Eckert numbers, while the mean Nusselt number shows a significant increase with Eckert number. This suggests that viscous dissipation primarily enhances heat transfer without substantially altering wall shear stress in these regimes. Conversely, under free convection (Gr=105), both mean friction factor and Nusselt number exhibit a substantial increase with rising Eckert number, highlighting the dominant role of buoyancy forces and viscous dissipation in governing both heat transfer and energy losses. Detailed friction factor distribution profiles further illustrate these phenomena, revealing unique behaviors, particularly the emergence of a near-zero slope region in free convection at higher Eckert numbers.https://chal.usb.ac.ir/article_9848_c4f6fcdcd2555a77fa5cbb5bf7bd7ce0.pdfUniversity of Sistan and Baluchestan,
Iranian Society Of Mechanical EngineersChallenges in Nano and Micro Scale Science and Technology2821-000X14220260901Tailoring of band gap value of metal oxides - graphene oxide nano composites3136990310.22111/cnmst.2026.55100.1294ENMahdiShafiee AfaraniDepartment of Materials Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, IranSalmanMahakiDepartment of Materials Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, IranHamedKhosraviDepartment of Materials Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, IranJournal Article20260418Copper oxide (CuO), zinc oxide (ZnO), iron oxide (Fe<sub>2</sub>O<sub>3</sub>) and manganese oxide (Mn<sub>3</sub>O<sub>4</sub>) nano particles were in-situ synthesized on the graphene oxide (GO) nano platelets via precipitation method using hydrated metal salts and NaOH starting materials. The effect of composite formation on the structure, microstructure and band gap of nano composite samples were investigated. Results generally showed that crystalline phase of metal oxides was formed on the graphene oxide (GO) nanoplatelets. Furthermore, Fourier transform infrared (FTIR) spectra illustrated the corresponding bands of metal–oxygen bonds in all samples. In addition, Field emission scanning electron micrographs (FE- SEM) showed that nanoparticles were synthesized on the surface of graphene oxide nanoplatelets which were agglomerated in some areas. Moreover, Uv-Vis spectra of all nano composite samples were plotted. Composites represented lower optical band gap values than those of pure graphene oxide nanoplatelets due to formation of Interfacial charge transfer and Schottky junctions.https://chal.usb.ac.ir/article_9903_aa1d7941c0ea3466767865d4d473d6e1.pdfUniversity of Sistan and Baluchestan,
Iranian Society Of Mechanical EngineersChallenges in Nano and Micro Scale Science and Technology2821-000X14220260901Layered Double Hydroxide/Polyethylene Glycol Nanocomposite as a Solid-Phase Microextraction Fiber Coating for Pesticide Determination in Cucumber and Tomato Samples37441005510.22111/cnmst.2026.55211.1298ENMarziehPiryaeiuniversity of maraghehMehdiAbolghasemiuniversity of maraghehHamedFaramarziuniversity of maraghehJournal Article20260429A novel layered double hydroxide/polyethylene glycol (LDH/PEG) nanocomposite was synthesized via a co-precipitation method and evaluated for the first time as a headspace solid-phase microextraction (HS-SPME) fiber coating for the simultaneous determination of thirteen multiclass pesticides (diazinon, fenitrothion, malathion, chlorpyrifos, penconazole, profenofos, cyproconazole, diniconazole, propiconazole, tebuconazole, fenpropathrin, phenothrin, and phosalone) in cucumber and tomato samples. The morphology and structure of the prepared SPME fiber were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Key extraction parameters including extraction temperature, sample pH, and extraction time were systematically optimized. Under the optimal conditions, the method showed linear ranges of 0.1–1000 μg L⁻¹ for chlorpyrifos and cyproconazole, and 1–1000 μg L⁻¹ for the other analytes, with coefficients of determination (R²) between 0.985 and 0.998. Limits of detection (LODs) ranged from 0.05 to 0.50 μg L⁻¹, and relative standard deviations (RSDs) at 1000 μg L⁻¹ were 3.9–8.9% (n = 3). The proposed HS-SPME method using the LDH/PEG nanocomposite fiber exhibited good analytical performance with LODs and RSDs comparable or superior to those reported in previous studies. The developed method was successfully applied to real cucumber and tomato samples with satisfactory relative recoveries.https://chal.usb.ac.ir/article_10055_c827221310fff0b7e103f853ea500ba4.pdfUniversity of Sistan and Baluchestan,
Iranian Society Of Mechanical EngineersChallenges in Nano and Micro Scale Science and Technology2821-000X14220260901Catalytic Degradation of Tetracycline in Aqueous Solution Using Cu-Modified γ-MnO2 Nanostructures45561005610.22111/cnmst.2026.55742.1308ENAlirezaKhorshidiFaculty Of Sciences, Namjoo Str. Rasht, GuilanMasoumehKeramatiFaculty of Chemistry, University of GuilanJournal Article20260610Tetracycline antibiotics are among the most recalcitrant micropollutants detected in aquatic environments, posing significant threats to public health due to their low biodegradability, promotion of antibiotic resistance, and endocrine-disrupting potential. In this study, γ-MnO2 and Cu-modified γ-MnO2 (Cu-γ-MnO2) nanostructures were successfully synthesized and evaluated as heterogeneous catalysts for the oxidative degradation of tetracycline in aqueous solution in the presence of H2O2. The synthesized materials were thoroughly characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FTIR). XRD confirmed the pure γ-MnO2 phase for both materials, with Cu incorporation causing no new crystalline phases but inducing a slight reduction in crystallite size. FE-SEM revealed a unique hedgehog-like morphology with needle-shaped nanocrystals assembled into spherical superstructures (17–36 nm), which was preserved upon Cu modification. Under optimized conditions (pH 4, 55°C, 20 mg catalyst, 1 mL of 30% H2O2, 20 min), Cu-γ-MnO2 achieved 98% tetracycline degradation, significantly outperforming unmodified γ-MnO2 (70%). The reaction followed NLLS biphasic kinetics (k₁ = 1.343 min−1 (R2 = 0.979). The Cu-γ-MnO2 catalyst demonstrated exceptional recyclability, retaining >80% activity after seven consecutive cycles, underscoring its practical feasibility for wastewater remediation applications.https://chal.usb.ac.ir/article_10056_067e0586b30697c2d8b6ee2b4c62ed1e.pdfUniversity of Sistan and Baluchestan,
Iranian Society Of Mechanical EngineersChallenges in Nano and Micro Scale Science and Technology2821-000X14220260901Coumarin-conjugated silver nanoparticles; potent antibacterial and antibiofilm agents against Multidrug-resistant Pseudomonas aeruginosa57671005710.22111/cnmst.2026.55806.1310ENEnsiyehAbbaspour NaderiDepartment of Biology, Ra.C., Islamic Azad University, Rasht, Iran.Seyedeh ToobaShafighiDepartment of Biology, Ra.C., Islamic Azad University, Rasht, Iran.AmirMirzaieDepartment of Biology, Pa.C., Islamic Azad University, Parand, IranAliSalehzadehDepartment of Biology, Ra.C., Islamic Azad University, Rasht, Iran.Journal Article20260615Multidrug-resistant (MDR) Pseudomonas aeruginosa is a major health threat in the community and hospital setting. This work investigates the antibacterial and antibiofilm effects of coumarin-conjugated silver nanoparticles (Ag@Glu-Coumarin NPs) on MDR P. aeruginosa. Silver NPs were initially functionalized with glucose, conjugated with coumarin and characterized by FT-IR, XRD, FE-SEM, EDS-mapping, DLS, zeta potential and TGA analyses. Antibacterial potential of the NPs was studied by disk diffusion and broth microdilution assays. Biofilm formation ability of P. aeruginosa strains and antibiofilm effects of Ag, coumarin and Ag@Glu-Coumarin NPs were analysed using the crystal violet staining method. The relative expression of the algD, pelA, and pslA genes was investigated by real-time PCR. The Ag@Glu-Coumarin NPs were correctly synthesized with a spherical shape and average size of 80 nm. The surface charge and hydrodynamic size of the particles were -80.4 mV and 271.2 nm, respectively and exhibited sufficient thermal stability at temperatures up to 100 °C. The average diameter of growth inhibition zones caused by Ag@Glu-Coumarin NPs was 30mm, and the minimum growth inhibitory concentration ranged 256-512μg/mL. The strains 1, 6, 7, 8 and 10 displayed the highest biofilm formation potential, which was reduced by 77.3, 75.9, 90.3, 89.2 and 89.4%, respectively, in treated bacteria. Moreover, treatment of P. aeruginosa strains with Ag@Glu-Coumarin NPs significantly reduced expression of the algD, pelA and pslA genes to 0.68, 0.46 and 0.37 folds, respectively. This study shows efficient growth inhibitory and antibiofilm effects of Ag@Glu-Coumarin NPs, suggesting their therapeutic potential against MDR P. aeruginosa strain.https://chal.usb.ac.ir/article_10057_dfcb75586ea287d843dbba69c0229a05.pdf