Showing 692 results for Type of Study: Research Paper
Mohammad Badaruddin, Ahmad Kurniawan Purga, Dwi Asmi, Sugiyanto Sugiyanto, Slamet Sumardi, Andreas Luki Indratmoko,
Volume 22, Issue 1 (3-2025)
Abstract
The investigation of SUP9 steel under the hot-rolling conditions for applications to leaf spring suspension focused on its tensile and fatigue crack growth (FCG) properties. In order to investigate the tensile properties, tensile specimens were fabricated in the longitudinal-transverse (LT) direction. Furthermore, in order to evaluate fatigue crack growth (FCG) behaviour, compact tensile (CT) specimens with different crack plane orientations in both the LT and transverse-longitudinal (TL) directions were employed. Microstructural and fractographic analyses were conducted using optical microscope (OM) and scanning electron microscopy (SEM). The hot-rolling process reduced the interlamellar spacings of Fe3C, enhancing the tensile properties through strain hardening. A high yield-to-ultimate strength ratio (~0.623) indicates excellent plastic deformation capability and resistance to fatigue crack growth, making SUP9 steel suitable for the leaf spring suspension system. Furthermore, the exponential crack growth rate constant, m, was found to be 3.066 in the TL direction and 3.265 in the LT direction, indicating that cracks propagate more rapidly in the LT orientation. Additionally, non-metallic inclusions, such as spherical oxides and MnS precipitates in LT specimens, were observed to facilitate faster crack growth in the transverse direction.
Ram Chhavi Sharma,
Volume 22, Issue 1 (3-2025)
Abstract
The effect of different Nd and PT compositions on the electrical and ferroelectric properties of (1-y)Bi1-xNdxFeO3-yPbTiO3 solid solutions, where x = 0.05, 0.10, 0.15, 0.20 and y = 0.1, 0.2, 0.3, and 0.4, was investigated to optimise material performance. Nd doping enhances the frequency-dependent dielectric properties of produced solid solutions. However, an anomaly in the dielectric loss tangent, which is consistent with the Debye relaxation process, is observed for compositions with x˂0.10 and y≥0.2 values in the frequency range of 1 KHz to 1 MHz. Dielectric anomalies were more noticeable around the transition temperature in temperature-dependent dielectric characteristics plots, suggesting stronger magnetoelectric interactions. The decrease in the dielectric constant for solid solution compositions with y ≥0.3 indicates the presence of MPB with BFO due to an increase in the tetragonal phase of the PbTiO3 compound. As Nd content increases, temperature-dependent dielectric permittivity predicts relaxor-type ferroelectric performance for y=0.4 composition of solid solutions. A ferroelectric investigation showed that saturation polarisation, remnant polarisation, and coercive field of all prepared solid solutions decrease with increased Nd doping. However, for y˃0.3 composition, a substantial rise in these parameters was observed, which is a result of electric order dominating over magnetic order in solid solutions. The study reveals that Nd doping reduces leakage current, making it a promising contender for future applications
Payam Tayebi, Ramin Hashemi,
Volume 22, Issue 1 (3-2025)
Abstract
This study presents the manufacturing of Al 1050/Mg AZ31B bimetallic sheets using the cool roll bonding process, followed by an investigation of the effect of annealing temperature on mechanical properties and microstructural features. Annealing treatment was performed at 200, 300, and 400 degrees Celsius. Mechanical testing includes tension, micro-hardness, three-point bending, and fracture toughness. Scanning electron microscopy equipped with energy-dispersive X-Ray spectroscopy (SEM-EDX) and X-ray diffraction (XRD) were used to investigate the microstructure in the infiltration zone. Mechanical testing shows that increasing the annealing temperature decreases the tensile strength of the two-layer specimens. Micro-hardness, XRD, and SEM-EDX investigations confirm the presence of intermetallic particles in the penetration zone. The Micro- hardness test showed that with the increase of the annealing temperature, the hardness in the penetration zone of Al 1050/Mg AZ31B increases. This increase in micro-hardness result confirms the presence of harder intermetallic phases with increasing annealing temperature in the penetration zone.
Zeinab Abbasali Karajabad, Adrine Malek Khachatourian, Mohammad Golmohammad, Ali Nemati,
Volume 22, Issue 1 (3-2025)
Abstract
Hybrid asymmetric supercapacitors using distinct cathode/anode materials offer enhanced energy density by expanding operational potential windows compared to symmetric configurations. In this work rGO/α-Fe₂O₃ and rGO/TiO₂ nanocomposites were synthesized via hydrothermal method for hybrid asymmetric supercapacitors applications. Field emission scanning electron microscope (FESEM) revealed uniform distribution of spherical α-Fe₂O₃ and TiO₂ nanoparticles on rGO sheets. The X-ray diffractometry (XRD) analysis confirmed the presence of the hematite and anatase in the rGO/α-Fe2O3 and rGO/TiO2 nanocomposites, respectively. Additionally, in the XRD spectra of both nanocomposites, a broad peak corresponding to the (002) crystalline planes of rGO was observed. Electrochemical testing showed specific capacities of 130 F/g (rGO/α-Fe₂O₃) and 253 F/g (rGO/TiO₂) at 5 mV/s in 1M KOH. The assembled hybrid asymmetric supercapacitors (rGO/α-Fe₂O₃//rGO/TiO₂) achieved a 1.6 V operational potential window. Power density and energy density of 1066 W kg-1 and 9.7 Wh kg-1 were achieved at a current density of 1 A/g, respectively.
Adil Kadum Shakir, Ebrahim Ghanbari-Adivi, Aref S. Baron Baron, Morteza Soltani,
Volume 22, Issue 1 (3-2025)
Abstract
Nanomaterials have significantly transformed multiple scientific and technological fields due to their exceptional properties, which result from their quantum confinement effects and high surface-to-volume ratios. Among these materials, zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles have attracted considerable interest because of their diverse applications.
In this study, TiO2-ZnO nanocomposites were synthesized using varying calcination times of 1, 1.5, 2, 2.5, and 3 hours. Characterization of fabricated samples through X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDXS) confirmed the successful fabrication of the nanocomposites. In this regard, XRD analysis revealed anatase TiO2 and hexagonal wurtzite ZnO phases. Raman spectroscopy also supported these findings, identifying characteristic peaks of both TiO2 and ZnO.
The calcination time had a minimal effect on the crystal structures and also morphology of the nanocomposites, which gave rise to its negligible impact on optical properties and biological activities of the samples. Optical properties assessed by means of UV-visible and photoluminescence (PL) spectroscopy showed consistent band gap absorption and emission profiles across all samples, among which the nanocomposite calcined for 1 hour exhibited the best optical properties.
The sample prepared at 1 hour not only showed the most favorable optical properties, but also demonstrated significant antibacterial, antifungal, and cytotoxic activities, which make it suitable for various applications. In this regard, a reduction of more than 99.9% occurred in the number of Escherichia coli and Staphylococcus aureus bacteria and also Candida albicans fungus by using TiO2-ZnO nanocomposite. Besides, addition of 500 µg/ml of nanocomposite decreased the cell viability to 34.47%, which signifies its high cytotoxicity activity.
Amirreza Bali Chalandar, Amirreza Farnia, Hamidreza Najafi, Hamid Reza Jafarian,
Volume 22, Issue 1 (3-2025)
Abstract
This study investigates the microstructural evolution and variations in the mechanical properties of pre-cold worked Nimonic 80A superalloy, subjected to two levels of deformation (25% and 50%) and welded via Gas Tungsten Arc Welding (GTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) techniques using ER309L filler wire. The objective is to evaluate the effect of the initial microstructure on the welding behavior of Nimonic 80A and compare the weldments produced using GTAW and PCGTAW. Microstructural characterization was conducted using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). XRD analysis demonstrated that the welding pulsed current mode, compared to the continuous current mode and at equal heat input, led to a refined microstructure, suggesting improved welded mechanical properties of the weld. It also showed a potential reduction in grain refinement with a higher level of cold work. Tensile testing demonstrated that fractures consistently occurred within the weld zone (WZ), with the PCGTAW sample achieving the highest tensile strength (766 MPa). Microhardness analysis indicated a notable reduction in hardness within the heat-affected zone (HAZ) and WZ, particularly in the 50% pre-cold worked sample. However, PCGTAW retained higher hardness due to its refined microstructure. The weld metal primarily consisted of an austenitic microstructure characterized by dendrites and interdendritic precipitates. Microstructural analysis revealed that welding induced significant changes in the weldment, with the PCGTAW sample exhibiting a more uniform microstructure and smoother transitions at the weld interface. Fractography confirmed ductile fracture in all specimens, with smoother and more uniformly distributed dimples in the PCGTAW sample. These findings highlight the advantages of pulsed current welding in optimizing the mechanical performance of Nimonic 80A welds and suggest its potential application in industries requiring superior weld quality.
Mohammad Derakhshani, Saeed Rastegari, Ali Ghaffarinejad,
Volume 22, Issue 1 (3-2025)
Abstract
In this research, the morphology of the Ni-W coating was modified by adding graphene oxide (GO) nanosheets in such a way that a foam-like structure with high porosity and holes in the form of intertwined tunnels was obtained. Different amounts of GO nanosheets were added to the plating bath and the resulting coating was examined. In order to estimate the electrochemically active surface area, the cyclic voltammetry (CV) test was used. Moreover, the linear polarization test (LSV) and chronoamperometry in 1 M NaOH were conducted to investigate the electrocatalytic activity for the hydrogen evolution reaction (HER). It was found that by adding 0.4 g/L GO to the electroplating bath, the electrocatalytic properties are doubled and the active surface of the electrode is significantly increased.
Amin Rahiminejad, Mojgan Heydari, Fariba Tajabadi,
Volume 22, Issue 1 (3-2025)
Abstract
Targeted drug delivery systems have been developed to overcome the disadvantages of conventional drug delivery systems and folate is one of the targeting molecules that has received attention in recent years. The attachment of this molecule to the surface of niosomal carriers has been achieved using Castor oil as an intermediate molecule. We synthesized caster folate (CF) and incorporate to noisome structure as biocompatible component for targeted delivery of anticancer drug Doxorubicin. This research studies the novelty of castor folate ester in the scope of niosome-based drug delivery systems. The aim was to investigate the feasibility of manufacturing and evaluating a niosomal carrier containing the drug doxorubicin hydrochloride (DOX) and its targeting by the combination of CF. The results of Fourier Transform Infrared Spectroscopy (FTIR) confirm chemical bounding between folic acid and castor oil. SEM showed good morphology with spherical structure of niosomes. These niosomes have particles size of 330 to 538 nm for different samples. Also, zeta potential was -28 to -40 mV that results good stability. The addition of CF to niosomal samples increased wettability and drug loading efficacy and along with DLS and zeta potential results confirms the folate impact on surface hydrophilicity of niosome spheres. The prepared formulations increased the effectiveness of doxorubicin on L929 fibroblast cells. The proposed biocompatible component showed the role of CF in the architectural integrity of niosomal lipid bilayers.
Shatha Batros, Farqad Rasheed, Hussein Hussein,
Volume 22, Issue 1 (3-2025)
Abstract
The copper oxide nanoparticles were synthesized using a precipitation method, recognized for its significance in antibacterial applications. This study reports the synthesis of pure CuO and CuO:Cd nanoparticles at two different concentrations, and explores their structural properties and antibacterial activity. The structural characteristics of the prepared powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Raman spectra were also examined using a 543 nm laser wavelength. XRD analysis confirmed that the as-synthesized samples exhibit a face-centered monoclinic structure, with crystallite size decreasing as dopant concentration increases, as estimated using the Scherrer method. The obtained crystallite sizes ranged from 7.13 to 11.72 nm, likely due to the larger atomic radius of Cd compared to Cu. The major Raman lines observed included Au2 (156 cm^-1), Ag (∼294 cm^-1), Bu2 (∼598 cm^-1), and lines at 1100 cm^-1 and 1420 cm^-1. The antibacterial activity of the synthesized CuO and CuO:Cd specimens was evaluated using the Kirby-Bauer disk diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The antibacterial activity increased with higher Cd concentrations and smaller particle sizes, resulting in larger inhibition zones and higher percentage inhibition ratios for both types of bacteria.
The copper oxide nanoparticles were synthesized using a precipitation method, recognized for its significance in antibacterial applications. This study reports the synthesis of pure CuO and CuO:Cd nanoparticles at two different concentrations, and explores their structural properties and antibacterial activity. The structural characteristics of the prepared powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Raman spectra were also examined using a 543 nm laser wavelength. XRD analysis confirmed that the as-synthesized samples exhibit a face-centered monoclinic structure, with crystallite size decreasing as dopant concentration increases, as estimated using the Scherrer method. The obtained crystallite sizes ranged from 7.13 to 11.72 nm, likely due to the larger atomic radius of Cd compared to Cu. The major Raman lines observed included Au2 (156 cm^-1), Ag (∼294 cm^-1), Bu2 (∼598 cm^-1), and lines at 1100 cm^-1 and 1420 cm^-1. The antibacterial activity of the synthesized CuO and CuO:Cd specimens was evaluated using the Kirby-Bauer disk diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The antibacterial activity increased with higher Cd concentrations and smaller particle sizes, resulting in larger inhibition zones and higher percentage inhibition ratios for both types of bacteria.
Ahmed Kharmouche,
Volume 22, Issue 1 (3-2025)
Abstract
Series of cobalt (Co) thin films with various thicknesses ranging from 50 to 400 nm have been fabricated using thermal heating under vacuum. We explore the impact of the thickness layer on the structural and morphological properties of the films. X-Ray diffractions and atomic force microscopy tools have been used to carry out the structural and the morphological properties of these films. The films are principally c-axis oriented, polycrystalline and with <0001> texture. The crystallites sizes have been found to range from 18.40 to 79.46 nm, and they increase with increasing thickness. The ratio c/a value indicates that Co films are subject to a tensile stress, probably because of the way the film grows. The microstrain is positive and ranges from 1.53 to 3.56%. Atomic force microscopy observations indicate the formation of crystallites according to the Stranski-Krastanov mode. The films topographical surfaces are very smooth, the average root mean square roughness ranging from 0.2 to 1.5 nm.
Keywords: Co; Thin films; XRD; Crystallite size; AFM.
Dr. U. Shinde, Somnath Handge, Dr. D. K Halwar,
Volume 22, Issue 2 (6-2025)
Abstract
This study investigates the effect of SnO2 as an additive on the structural, electrical, optical, and gas sensing properties of LaCrO3 nanoparticles. SnO2 is added into the LaCrO3 by weight percentage (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. %, 9 wt. % and 11 wt. %) employing screen printing method. Initially, the nanoparticles of SnO2 and LaCrO3 separately synthesis by sol-gel method and then used for the development of thick films. LaCrO3 is used as host material while SnO2 is additive material. The structural characterizations like FESEM, EDX and XRD were carried out to investigate the morphology, elements and crystallite size respectively. The inclusion of SnO2 modifies the crystalline structure and surface morphology of LaCrO3, as revealed by structural analyses. The optical characterizations like FTIR and UV were used for the study of impact of SnO2 additive on functional group and band gap of the host material respectively. Optical studies indicate a modification in the bandgap, affecting light absorption properties and indicating changes in electronic transitions. The electrical characterizations were conducted by using half bridge method. Electrical resistivity measurements show enhanced performance, likely due to variation in charge carrier mobility induced by the SnO2 additive. Among other selected wt. % SnO2 additives, 9 wt. % SnO2 added LaCrO3 thick films shows maximum sensitivity to CH4 gas at 120oC operating temperature. The gas sensing characteristics demonstrate enhanced sensitivity, selectivity, and response time to target gases, suggesting that SnO2 doping improves the sensing capabilities of LaCrO3 nanoparticles, making them more efficient as a gas sensor. Obtained findings suggest that, SnO2 as an additive enhances the multifunctional properties of LaCrO3 nanoparticles, making them promising candidates for advanced gas sensing applications.
Mahdi Rajaee, Mahdi Raoufi, Zeinab Malekshahi Beiranvand, Abbas Naeimi,
Volume 22, Issue 2 (6-2025)
Abstract
This research explored the impact of the nickel-to-manganese ratio and the influence of the matrix phase on the properties of W-Ni-Mn tungsten heavy alloys (WHAs), aiming to determine the optimal composition for achieving desirable alloy properties. For this purpose, tungsten, nickel, and manganese powders with specified weight percentages underwent two rounds of wet milling. Powder mixtures were obtained with weight ratios of 90W-6Ni-4Mn, 90W-8Ni-2Mn, and 88W-10Ni-2Mn. These mixtures were then compressed through the cold pressing method at a pressure of 250 MPa. Subsequent reduction and sintering processes were carried out in a tube furnace at temperatures of 1150 and 1400 °C, respectively. Microstructural characterization was conducted using both optical and electron microscopy. The results showed that the change in chemical composition is not significantly effective on the sintering density of the samples and also the highest sintering density, reaching 90.11%, was achieved with the 88W-10Ni-2Mn sample. Furthermore, the results demonstrated that carburization of W-Ni-Mn WHAs during the sintering process led to an increase in the micro-hardness of the samples. The highest hardness, measuring 381 Hv, was observed in the 90W-6Ni-4Mn alloy, where carburization occurred. XRD results revealed that an increase in the nickel-to-manganese ratio led to a reduction in the peaks of manganese carbide and tungsten carbide. Consequently, this decrease in carbide peaks resulted in a reduction in hardness, reaching 352 Hv in the case of the 88W-10Ni-2Mn sample. Additionally, the alloys 90W-6Ni-4Mn and 88W-10Ni-2Mn both exhibited the lowest continuity, a value of 0.5. Fracture surface SEM images illustrated that the 90W-6Ni-4Mn alloy, characterized by the lowest nickel-to-manganese ratio (1.5), exhibited the highest trans-granular fracture mode involving cleavage and matrix tearing, which is considered desirable. Furthermore, an increase in the matrix phase content resulted in a shift of the preferred crack path, originating from the matrix phase.
