Showing 8 results for Hasan
R. Hasanzadeh, T. Azdast, R. Eungkee Lee, A. Afsari Ghazi,
Volume 14, Issue 3 (September 2017)
Abstract
Material selection is a main purpose in design process and plays an important role in desired performance of the products for diverse engineering applications. In order to solve material selection problem, multi criteria decision making (MCDM) methods can be used as an applicable tool. Bumper beam is one of the most important components of bumper system in absorbing energy. Therefore, selecting the best material that has the highest degree of satisfaction is necessary. In the present study, six polymeric nanocomposite materials were injection molded and considered as material alternatives. Criteria weighting was carried out through analytical hierarchy process (AHP) and Entropy methods. Selecting the most appropriate material was applied using technique for order preference by similarity to ideal solution (TOPSIS) and the multi-objective optimization on the basis of ratio analysis (MOORA) methods respect to the considered criteria. Criteria weighting results illustrated that impact and tensile strengths are the most important criteria using AHP and Entropy methods, respectively. Results of ranking alternatives indicated that polycarbonate containing 0.5 wt% nano Al2O3 is the most appropriate material for automotive bumper beam due to its high impact and tensile strengths in addition to its low cost of raw material. Also, the sensitivity analysis was performed to verify the selection criteria and the results as well.
M. Abbasalizadeh, R. Hasanzadeh, Z. Mohamadian, T. Azdast, M. Rostami,
Volume 15, Issue 4 (December 2018)
Abstract
Shrinkage is one of the most important defects of injection molded plastic parts. Injection molding processing parameters have a significant effect on shrinkage of the produced parts. In the present study, the effect of different injection parameters on volumetric shrinkage of two polymers (high-density polyethylene (HDPE) semi-crystalline thermoplastics and polycarbonate (PC) as a representative of amorphous thermoplastics) was studied. Samples under different processing conditions according to a L27 orthogonal array of Taguchi experimental design approach were injected. Effect of material crystallinity on the shrinkage of injected samples was investigated. Obtained results revealed that semi-crystalline thermoplastics have larger shrinkage values in comparison with amorphous thermoplastics. Shrinkages of injected samples were also studied along and across the flow directions. Results showed that the flow path can dramatically affect the shrinkage of semi-crystalline thermoplastics. However for amorphous thermoplastics, results showed an independency of obtained shrinkage to flow direction. Analysis of variance (ANOVA) results illustrated that cooling time was the most effective parameter on shrinkage for both PE and PC injected samples; followed by injection temperature as the second important parameter. The optimum conditions to minimize shrinkage of injection molded samples are also achieved using signal to noise ratio (S/N) analysis.
A. Hasanvand, M. Pourabdoli, A. Ghaderi,
Volume 17, Issue 1 (March 2020)
Abstract
The main problem of cobalt oxide as a thermochemical heat storage material is its slow re-oxidation kinetics. In addition, redox (reduction and oxidation) behavior of as-received Co3O4 is degraded with increasing the number of redox cycles. To overcome this drawback, Al2O3 and Y2O3 were added to Co3O4 and effect of mechanical activation time (2, 4, 8, and 16 h) on the redox behavior (weight change value/rate, redox reversibility, reduction and re-oxidation values, and particle morphologies) of Co3O4-5 wt.% Al2O3 and Co3O4-5 wt. % Y2O3 composites was investigated using thermogravimetry method. The composites were studied by SEM, EDS, and X-ray map analyses before and after redox reactions. Results showed that increasing the mechanical activation time improves the redox kinetics of Co3O4-5wt. % Al2O3 in comparison with as-received Co3O4. Although, the alumina-containing samples, activated in short time showed the better redox kinetics than samples activated in long time. It was found that increasing the activation time to more than 8 h for alumina-containing samples reduces the redox kinetics due to decreasing the positive effect of Al2O3 in controlling the particle size growth and sintering. In the case of Co3O4-5wt. % Y2O3, an increase in activation time generally reduced the redox kinetics. As a result, redox reactions in a 16 h-activated Co3O4-5wt.% Y2O3 composite was completely stopped. In addition, results showed that weak performance of Co3O4-5 wt. % Y2O3 is related to intensive sintering and growth of cobalt oxide particles during redox reactions
R. Hasanzadeh, S. Fathi, T. Azdast, M. Rostami,
Volume 17, Issue 2 (June 2020)
Abstract
Heat transfer in foams consists of conduction through solid and gaseous phases, convection within the cells as well as radiation through the whole medium. Radiation thermal conduction affects the overall thermal conductivity by 40% in a high porosity. Therefore, the investigation of that term seems to be necessary. Radiation thermal conduction depends on the extinction coefficient which its determination is experimentally complex. In this study, this coefficient is theoretically estimated using Glicksman model for polyolefin foams and is verified in comparison with the experimental data. Extinction coefficient which plays an effective role in the radiation thermal conduction depends on the morphological properties including foam and solid densities, cell and strut diameters. The results demonstrate that the radiation thermal conduction decreases by reducing cell size and increasing foam density and strut diameter. An L25 orthogonal array of Taguchi approach is used for optimization of radiation thermal conduction respect to foam density, cell and strut diameters as variable parameters. The analysis of variance results illuminate that foam density and cell diameter with 58 and 32% contribution are the most effective parameters on the radiation thermal conduction, respectively. At optimum conditions according to the prediction tool of Taguchi approach, the radiation thermal conduction significantly decreases to 1.0908 mW/mK.
Ali Hasanzade Salmasi, Mahban Zarei, Shadab Safarzadeh Khosroshahi, Soolmaz Heidari, Farhood Najafi, Mojtaba Ghomayshi, Katayoun Lesani,
Volume 20, Issue 3 (September 2023)
Abstract
Amorphous calcium phosphate (ACP) which is a transient phase in natural bio-mineralization process has recently gained the spotlight. This study aimed to assess the effect of incorporation of nano-ACP (NACP) in a dental adhesive with/without surface treatment with silane coupling agent on bond strength. NACP was synthesized by the wet chemical precipitation technique. To characterize the structure of NACP, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy were used. Forty molars were randomized into 4 groups of 10. The teeth were restored with composite resin and the bonding agent (one of the four groups). Adper Single Bond 2 was used as the control group. In 4wt% NACP group, NACP fillers were added to the bonding agent. In 0.4wt% and 4wt% SNACP groups, silanized NACP fillers were added to the bonding agent. Finally, the mode of failure of specimens was determined. Data were analyzed by one-way ANOVA and Tukey's post-hoc tests. P<0.05 was considered statistically significant. Addition of 4wt% non-silanized NACP decreased the bond strength compared with the control group (P<0.05). The bond strength of the groups with silanized fillers was not significantly different from that of the control group. Addition of silanized NACP to dental adhesive had no significant adverse effect on bond strength, which is a promising finding to pave the way for the synthesis of bonding agents containing bioactive fillers.
Rihab Jabbar, Mohammed Alluaibi, Sara Shahatha, Dhuha Hasan,
Volume 21, Issue 0 (IN PRESS 2024)
Abstract
This study investigates the effect of sintering temperature on the structural, dielectric and magnetic properties of cobalt ferrite nanoparticles (CoFe₂O₄ NPs) synthesized by the sol–gel method. The samples were sintered at 400°C–1000°C for 2 h and characterized using XRD, FTIR, SEM, AFM, dielectric and VSM measurements. XRD confirmed the formation of a stable cubic spinel structure, with crystallite size increasing from 10.71 to 16.09 nm and porosity decreasing with increasing sintering temperature. SEM and AFM showed progressive grain growth and improved grain connectivity, with the sample at 800°C exhibiting the most uniform morphology before excessive grain growth occurred at 1000°C. The dielectric response showed decreasing real and imaginary permittivity with increasing frequency, while the sample at 800°C exhibited the lowest dielectric loss (tan δ ≈ 2 at 1 kHz). Magnetic measurements revealed ferrimagnetic behavior, with saturation magnetization increasing from 27.5 emu/g at 400°C to 68 emu/g at 1000°C, whereas coercivity reached a maximum of 715 Oe at 800°C. Overall, sintering at 800°C provided the best balance between microstructural uniformity, low dielectric loss and magnetic performance, making it a strong candidate for further evaluation in high-frequency and multifunctional magnetic applications.
Mohammad Abdullah Al Asad, Hasan Ridoy, Md. Shuzon Ali, Mst. Jeba Maimuna,
Volume 22, Issue 3 (September 2025)
Abstract
Perovskite materials have accumulated considerable attention in recent years for their exceptional electro-optical properties, creating them rising candidates for various uses in the fields of photovoltaics, light-emitting devices, and beyond. Among these perovskite materials, CsPbI3 stands out as a notable example due to its remarkable stability, tunable bandgap, and efficient light-emitting properties. The crystal structure, composition, and introductory properties of CsPbI3 perovskite using density functional theorem (DFT) being focused. In detailed exploration of Electronic property, Elastic property, Optical property, Population analysis, and shedding light on the unique attributes of this material highlighted this study. To do above computation we have used CASTEP in Material Studio.
Muayad Raheem Hussein, Sabah Hasan Jumaah, Ali N. Majees,
Volume 23, Issue 1 (MARCH 2026)
Abstract
In the current study, titanium dioxide (TiO₂) nanoparticles were synthesized and subsequently combined with chitosan (CS) and silver (Ag) to augment their antimicrobial effectiveness. The synthesized TiO₂, TiO₂-CS, and TiO₂-CS-Ag nanocomposites were subjected to various characterization analyses in order to thoroughly assess their structural, morphological, and compositional attributes. XRD analysis substantiated the phase transition from anatase to rutile consequent to incorporation of chitosan and silver, accompanied by a diminution in nanoparticle dimensions. FTIR spectra corroborated the existence of functional groups linked to chitosan and silver, while FESEM illustrated morphological modifications, notably the emergence of polygonal nanostructures within the TiO₂-CS-Ag composite. The antibacterial efficacy of the synthesized nanocomposites was evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Although pure TiO₂ demonstrated minimal antibacterial properties, the TiO₂-CS and TiO₂-CS-Ag composites exhibited substantial inhibition zones, with the most pronounced efficacy recorded for the TiO₂-CS-Ag composite attributable to the synergistic interaction between chitosan and silver nanoparticles. BET analysis revealed that the augmented antimicrobial activity was associated with the increased surface area of the TiO₂-CS-Ag nanocomposite.
