Sharif Digital Repository

The crystallization behavior of fluorphlogopite, a glass-ceramic in the MgO-SiO2-Al2O3-K2O-B 2O3-F system, was studied by substitution of Li 2O for K2O in the glass composition. DTA, XRD and SEM were used for the study of crystallization behavior, formed phases and microstructure of the resulting glass-ceramics. Crystallization kinetics of the glass was investigated under non-isothermal conditions, using the formal theory of transformations for heterogeneous nucleation. The crystallization results were analyzed, and both the activation energy of crystallization process as well as the crystallization mechanism were characterized. Calculated kinetic parameters indicated that the appropriate... 

Nickel-dimethylglyoxime complex (NiDMG) modified nickel electrode (Ni/NiDMG) showed a catalytic activity towards methanol oxidation in NaOH solution. The modified electrode prepared by the dimethylglyoxime anodic deposition on Ni electrode in the solution containing 0.20 mol L-1 NH4Cl + NH4OH (pH 9.50) and 1.0 × 10-4 mol L-1 dimethylglyoxime. The modified electrode conditioned by potential recycling in a potential range of 100-700 mV (vs. SCE) by cyclic voltammetry in alkaline medium (0.10 M NaOH). The results show that the NiODMG film on the electrode behaves as an efficient catalyst for the electrooxidation of methanol in alkaline medium via Ni(III) species formed on the electrode with the... 

The effects of various ratios of Fe/Ni/MgO and growth temperatures on yield, diameter and quality of multi-walled carbon nanotubes (MWCNTs) were studied. Thermal gravimetric analysis (TGA) confirmed that the MWCNT yield depends on Fe/Ni ratio with the following order; Fe0.5 Ni0.5 > Fe > Fe0.75 Ni0.25 > Fe0.25 Ni0.75 > Ni. The results indicated that there is an optimum temperature (940 °C) for the MWCNT growth both from quality and quantity (yield) aspects as compared to other temperatures. Moreover, the changes on Fe/Ni to MgO ratio for the MWCNT growth revealed that Fe/Ni/MgO with the ratio of 17.5/17.5/65 had the highest quality and surface area as compared to the other ratios. The... 

The effects of HCl, HNO3, H2SO4 and HF acids on the purification and the electrochemical hydrogen storage of multi-walled carbon nanotubes (MWCNTs) were studied. The MWCNTs were synthesized on Fe-Ni catalyst by thermal chemical vapor deposition method. The X-ray diffraction and thermal gravimetric analysis results indicated that the MWCNTs purified by HF acid had the highest impurities as compared with the other acids. The N2 adsorption results at 77 K indicated that all the samples were mainly mesoporous and the purified MWCNTs by HF acid had the highest surface area as compared with the other acids. The hydrogen storage capacities of the purified MWCNTs by the following acids were in... 

The heat transfer Magnetohydrodynamics flows have been potentially used to enhance the thermal characteristics of several systems such as heat exchangers, electromagnetic casting, adjusting blood flow, X-rays, magnetic drug treatment, cooling of nuclear reactors, and magnetic devices for cell separation. Our concern in this article is to numerically investigate the flow of an incompressible Magnetohydrodynamics micropolar fluid with heat transportation through a channel having porous walls. By employing the suitable dimensionless coordinates, the flow model equations are converted into a nonlinear system of dimensionless ordinary differential equations, which are then numerically treated for... 

The purpose of the paper is to develop a mathematical foundation for exploring the complex interaction of Coriolis and Lorentz forces with the electromagnetohydrodynamic (EMHD) flow of a power-law fluid inside a microchannel with wall slip condition. Both the Lorentz and Coriolis forces act orthogonally to each other. Mathematical modeling of the problem is based on a set of classical Maxwell and Navier–Stokes equations, which are subsequently solved numerically by employing an implicit finite difference methodology. The numerical solution thus obtained has been found to be in an excellent agreement correlation with the ones reported in the scientific literature, for some limiting cases. A... 

Performance of rotary ultrasonic machining (RUM) system greatly influences by appropriate design of ultrasonic horn. Ultrasonic stepped horn gives high amplitude of vibration and better cutting efficiency but design and integration of horn with RUM system is highly intricate. Therefore, systematic study on design and implementation of ultrasonic stepped horn was needed in order to achieve better efficiency of RUM process. This paper focuses on design aspects of ultrasonic stepped horn by theoretical, FE simulations and modeling techniques. The designed horn was integrated with RUM system, performance was measured in terms of ultrasonic resonant frequency through FE simulations and modeling... 

Nano-fluids have considerable importance in the field of thermal development that relates to several industrial systems. There are some key applications in recent construction systems flow, as well as microscale cooling gadgets and microstructure electric gadgets for thermal migration. The current investigation concludes the study of electrically conducting nano-fluid flow and heat transfer analysis in two-dimensional boundary layer flow over a curved extending surface in the coexisting of magnetic field, heat generation and thermal radiation. The small sized particles of copper (Cu) are taken as nanoparticles and water is assumed to be the base fluid. We used quasi-linearization and central... 

Illegal money lending has become a growing issue in Malaysia, especially with the activities of the Ah Long syndicate. This practice poses a significant threat not only to the country's financial integrity but also to the welfare of its citizens. The dual legal system in Malaysia, where civil and Shari’ah laws coexist, makes it challenging to regulate these activities. Despite the efforts made by the Central Bank of Malaysia to curb illegal lending, many Malaysians still resort to Ah Long loans due to limited access to inclusive financial services. In 2021 alone, over 20,000 complaints of violence related to Ah Long's activities were reported. To address this issue, a Shari’ah-compliant... 

The Hamas attack on Israel on 7 October 2023 has amplified debate on the longstanding Israeli-Palestinian conflict, which has persisted for more than a century. This article dissects the legitimacy and ethical implications of Israel’s military actions in Palestine and argues that the thin line between self-defence and aggression has been excessively surpassed by Israel’s actions against the Palestinians. to the analysis of this article is the application of Article 51 of the Charter of the United Nations and also an assessment of the implication of genocide in light of Israel’s actions. This article presents a scrutiny of ramifications of Israel’s invocation of self-defence in the... 

Ternary hybrid nanofluids possess several potential applications in the modern science beyond just the heat transfer efficiency. A continuous research and advancements on binary and ternary hybrid nanofluids might lead towards new developments in many technological and scientific zones. Ongoing research interprets and distinguishes the novel attributes of the sodium alginate (Na.C6H7O6) based unary, binary and ternary nanofluids through a porous medium under induced magnetic field environment. The nano-composition of single-wall carbon nanotubes (SWCNT) with silver (Ag) and molybdenum dioxide (MoS2) gives rise to the binary (SWCNT-Ag/Na.C6H7O6) and ternary hybrid (SWCNT-Ag-MoS2/Na.C6H7O6)...