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Influence of binder composition on the rheological behavior of injection-molded microsized siC suspensions

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Journal of University of science and Technology Beijing 2008年第3期15卷 297-301页

作者： islam s.Humail school of materials science and Engineering University of Science and Technology Beijing

The influence of four kinds of binders consisting of paraffin wax （PW）, random-polypropylene （RPP）, high-density polyethylene （HDPE）, and stearic acid （sA） on the theological behavior of injection-molded siC feedstocks was investigated over a temperature range of 150℃ to 180℃ and a shear rate range of 4 s^-1 to 1259 s^^-1. The results showed that all the feedstocks exhibited pseudoplastic flow behavior. The wax-based binder of multipolymer components （PW-RPP-HDPE） exhibited better comprehensive rheological properties compared with the binder of monopolymer components （PW-RPP or PW-HDPE）. The addition of 5wt% sA to the binder could reduce the viscosity of the feedstock but enhance the rheological stability by improving the wettability between the binder and the siC powder. The binder of 65wt% PW ＋ 15wt% HDPE ＋ 15wt% RPP ＋ 5wt% sA was found to be a better binder for microsized siC injection molding.

关键词： siC powder injection molding rheology binder

Variation of the mechanical properties of tungsten heavy alloys tested at different temperatures

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Rare metals 2011年第4期30卷 392-395页

作者： s.H.islam Research Center College of EngineeringKing Saud University

The high-temperature mechanical properties of 95W-3.5Ni-1.5Fe and 95W-4.5Ni-0.5Co alloys were investigated in the temperature range of room temperature to1100℃. The yield strength and tensile strengths declined gradually, and the ductility of both alloys increased as the testing temperature was increased to 300℃. All the three properties reached a plateau at temperatures between 300 and 500℃ in the case of 95W-3.5Ni-l.5Fe and at temperatures between 350 and 700℃ in the case of 95W-4.5Ni-0.5Co. Thereafter, the ductility as well as yield and tensile strengths decreased considerably.

关键词： liquid phase sintering tungsten alloys tensile testing mechanical properties

Field-dependent resistive transitions in YBa_2Cu_3O_(7-δ) thin films:Influence of the pseudogap on vortex dynamics

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Chinese Physics B 2015年第1期24卷 467-473页

作者： s H Naqib R s islam Department of Physics University of RajshahiRajshahi-6205 Bangladesh

The nature of resistive transition of high-quality crystalline thin films of YBa2Cu3O7-δhas been studied under magnetic fields（H） applied along the c direction over a wide range of doped holes, p, in the Cu O2 planes. The field- and temperature-dependent in-plane resistivity, ρab（T, H）, has been analyzed within the thermally assisted flux-flow（TAFF）formalism. The flux activation energy, U（T, H）, has been extracted from this analysis. The low-T part of the ρab（T, H）data can be described by an activation energy having the functional form of U（T, H） =（1- t）m（H-0/H）β, where t = T /Tc（reduced temperature）, and H0 is a field scale that primarily determines the magnitude of U（T, H）. The temperature exponent, m, shows a systematic variation with p, whereas the field exponent, β, is insensitive to the p values and is close to unity. The H0, on the other hand, changes rapidly as p is varied. U（T, H） is linked to the pinning potential and consequently on the superconducting condensation energy. since the normal state pseudogap directly affects superconducting condensation energy, a clear correspondence between H0 and the PG energy scale, ε g, is found. Possible implications of these results are discussed.

关键词： Y123 superconductors thermally assisted flux-flow model activation energy pseudogap

The Two-Dimensional supersonic Flow and mixing with a Perpendicular Injection in a scramjet Combustor

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Journal of Thermal science 2003年第4期12卷 371-380页

作者： mohammad Ali s. Ahmed A.K.m. sadrul islam Department of mechanical Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh.Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh.Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh.

A numerical investigation has been performed on supersonic mixing of hydrogen with air in a scramjet (supersonic Combustion Ramjet) combustor and its flame holding capability by solving Two-Dimensional full Navier-stokes equations. The main flow is air entering through a finite width of inlet and gaseous hydrogen is injected perpendicularly from the side wall. An explicit Harten-Yee Non-mUsCL modified-flux-type TVD scheme has been used to solve the system of equations, and a zero-equation algebraic turbulence model to calculate the eddy viscosity coefficient. In this study the enhancement of mixing and good flame holding capability of a supersonic combustor have been investigated by varying the distance of injector position from left boundary keeping constant the backward-facing step height and other calculation parameters. The results show that the configuration for small distance of injector position has high mixing efficiency but the upstream recirculation can not evolved properly which is an important factor for flame holding capability. On the other hand, the configuration for very long distance has lower mixing efficiency due to lower gradient of hydrogen mass concentration on the top of injector caused by the expansion of side jet in both upstream and downstream of injector. For moderate distance of injector position, large and elongated upstream recirculation can evolve which might be activated as a good flame holder.

关键词： scramjet engine TVD scheme finite width of inlet supersonic mixing parallel air stream flame holding.

Abundant closed-form wave solutions to the simplified modified Camassa-Holm equation

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Journal of Ocean Engineering and science 2023年第3期8卷 238-245页

作者： s m Rayhanul islam s m Yiasir Arafat Hanfeng Wang school of Civil Engineering Central South UniversityChangshaHunan 410075China Department of mathematics Pabna University of Science and TechnologyPabna 6600Bangladesh

The simplified modified Camassa-Holm (smCH) equation is an important nonlinear model equation for identifying various wave phenomena in ocean engineering and science. The new auxiliary equation (NAE) method has been applied to the smCH equation. Base on the method, we have obtained some novel an- alytical solutions such as hyperbolic, trigonometric, exponential, and rational function solutions of the smCH equation. For appropriate values of parameters, three dimensional (3D) and two dimensional (2D) graphs are designed by mathematica. The stability of the model is also discussed in this manuscript. The dynamic and physical behaviors of the solutions derived from the smCH equation have been ex- tensively discussed by these plots. All our solutions are indispensable for understanding the nonlinear phenomena of dispersive waves that are important in ocean engineering and science. In addition, our results are essential to clarify the various oceanographic applications containing ocean gravity waves, offshore rig in water, energy associated with a moving ocean wave and numerous other related phenom- ena. Finally, the obtained solutions are helpful for studying wave interactions in many new structures and high-dimensional models.

关键词： smCH equation NAE method Nonlinear physics Kink shape solitary wave

The impact of alpha-fetoprotein (AFP), child-turcotte-pugh (CTP) score and disease staging on the survival of hepatocellular carcinoma (HCC) patients: a retrospective cohort from single oncology center

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Oncology research 2025年第1期33卷 149-160页

作者： Nasser mulla Yousef Katib Asim m Almughamsi Duaa s Alkhayat mohamed mosaad samir T Alfotih Rawan Alaofi Department of Internal medicine Faculty of Medicine Taibah University Madinah 42278 Saudi Arabia. Department of Radiology Faculty of Medicine Taibah University Madinah 42278 Saudi Arabia. Department of surgery Faculty of Medicine Taibah University Madinah 42278 Saudi Arabia. Department of Endemic and Infectious Diseases Suez Canal University Ismailia 41522 Egypt. King salman bin Abdulaziz medical City Madinah 42311 Saudi Arabia. Prince mohammed Bin Abdulaziz Hospital Madinah 41511 Saudi Arabia.

Background:Hepatocellular carcinoma (HCC) is the most common cause of cancer-related death in saudi Arabia. Our study aimed to investigate the patterns of HCC and the effect of TNm staging, Alfa-fetoprotein (AFP), and Child-Turcotte Pugh (CTP) on patients' overall survival (Os).methods:A retrospective analysis was conducted on 43 HCC patients at a single oncology center in saudi Arabia from 2015 to 2020. All patients had to fulfill one of the following criteria: (a) a liver lesion reported as definitive HCC on dynamic imaging and/or (b) a biopsy-confirmed diagnosis.Results:The mean patient age of all HCC cases was 66.8 with a male-to-female ratio of 3.3:1. All patients were stratified into two groups: viral HCC (n = 22, 51%) and non-viral HCC (n = 21, 49%). Among viral-HCC patients, 55% were due to HBV and 45% due to HCV. Cirrhosis was diagnosed in 79% of cases. Age and sex did not significantly statistically differ in Os among viral and non-viral HCC patients (-value > 0.05). About 65% of patients had tumor size >5 cm during the diagnosis, with a significant statistical difference in Os (-value = 0.027). AFP was >400 ng/ml in 45% of the patients. There was a statistically significant difference in the Os in terms of AFP levels (-value = 0.021). A statistically significant difference was also observed between the CTP score and Os (-value = 0.02). CTP class B had the longest survival. BsC was the most common treatment provided to HCC patients followed by sorafenib therapy. There was a significant statistical difference in Os among viral and non-viral HCC patients (-value = 0.008).Conclusions:The most common predictors for Os were the underlying cause of HCC, AFP, and tumor size. Being having non-viral etiology, a tumor size >5 cm, an AFP > 400 ng/mL, and a CTP score class C were all negatively associated with Os.

关键词： Alpha-fetoprotein (AFP) Child-turcotte-pugh Hepatocellular carcinoma Pattern Progression free survival

Dynamic response in two-dimensional transversely isotropic thick plate with spatially varying heat sources and body forces

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Applied mathematics and mechanics(English Edition) 2011年第10期32卷 1315-1332页

作者： m.islam s.H.mALLIK m.KANORIA Department of mathematics St. Xavier's College (Evening) Kolkata 700016 India Department of mathematics Aliah University Kolkata 700091 India Department of Applied mathematics University of Calcutta Kolkata 700009 India

This paper deals with a two-dimensional （2D） problem for a transverselyisotropic thick plate having heat sources and body forces. The upper surface of the plate is stress free with the prescribed surface temperature, while the lower surface of the plate rests on a rigid foundation and is thermally insulated. The study is carried out in the context of the generalized thermoelasticity proposed by Green and Naghdi. The governing equations for displacement and temperature fields are obtained in the Laplace-Fourier transform domain by applying the Laplace and Fourier transforms. The inversion of the double transform is done numerically. Numerical inversion of the Laplace transform is done based on the Fourier series expansion. Numerical computations are carried out for magnesium （mg）, and the results are presented graphically. The results for an isotropic material （Cu） are obtained numerically and presented graphically to be compared with those of a transversely isotropic material （mg）. The effect of the body forces is also studied.

关键词： generalized thermoelasticity Green-Naghdi model transversely isotropic material spatially varying heat source body force

An ab initio investigation of vibrational, thermodynamic, and optical properties of sc_2AlC mAX compound

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Chinese Physics B 2016年第10期25卷 103-108页

作者： m A Ali m T Nasir m R Khatun A K m A islam s H Naqib Department of Physics Chittagong University of Engineering and Technology Department of Arts & sciences Bangladesh Army University of Science and Technology Department of Physics University of Rajshahi International islamic University Chittagong

The structural vibrational, thermodynamical, and optical properties of potentially technologically important, weakly coupled mAX compound, sc2 Al C are calculated using density functional theory(DFT). The structural properties of scAlC are compared with the results reported earlier. The vibrational, thermodynamical, and optical properties are theoretically estimated for the first time. The phonon dispersion curve is calculated and the dynamical stability of this compound is investigated. The optical and acoustic modes are observed clearly. We calculate the Helmholtz free energy(F), internal energy(E), entropy(s), and specific heat capacity(Cv) from the phonon density of states. Various optical parameters are also calculated. The reflectance spectrum shows that this compound has the potential to be used as an efficient solar reflector.

关键词： mAX compound phonon dispersion thermodynamical properties optical properties

self-propagating high temperature synthesis of mosi_2 matrix composites

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Rare metals 2006年第3期25卷 225-230页

作者： Akhtar Farid s.H. islam materials science and Engineering school State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

mosi2 is presently regarded as the most important material for electrical heating and as one with huge potential for high temperature structural uses. mosi2 and mosi2 matrix composites were prepared by self-propagating high temperature synthesis （sHs）. Pure mosi2 was obtained and a compound of mosi2 and Wsi2was synthesized in the form of predominant solid solution （mo,W）si2. By adding aluminum of 5.5 at.% to mo-si, the crystal structure of mosi2 changed into a mixture of tetragonal Cllb mosi2and hexagonal C40 mo（si,Al）2. The （mo,W）si2-mo（si,Al）2-W（si,Al）2 composite materials were synthesized by adding aluminum of 5.5 at.% to mo-W-si. However, if the amount of the added aluminum was not larger than 2.5 at.%, it did not have any significant effect. sHs is an effective technology for synthesis of mosi2 and mosi2 matrix composites.

关键词： powder metallurgy mosi2 matrix composites self-propagating high temperature synthesis molybdenumtungsten disilicide molybdenum aluminosilicide