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Complex impedance and electric modulus studies of magnetic ceramic Ni_(0.27)Cu_(0.10)Zn_(0.63)Fe_(2)O_(4)

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Journal of Advanced Ceramics 2015年第3期4卷 217-225页

作者： M.BELAL HOSSEN A.K.M.AKTHER hossain Department of Physics Chittagong University of Engineering and TechnologyChittagongBangladesh Department of Physics Bangladesh University of Engineering and TechnologyDhakaBangladesh

The electrical properties of Ni_(0.27)Cu_(0.10)Zn_(0.63)Fe_(2)O_(4)(NCZF)prepared from auto combustion synthesis of ferrite powders have been studied by impedance and modulus *** studied frequency and temperature dependencies of impedance and electric modulus of NCZF in a wide frequency range(20 Hz-5 MHz)at different measuring temperatures T_(SM)(30-225℃).The complex impedance spectra clearly showed both grain and grain boundary effects on the electrical *** observed impedance spectra indicated that the magnitude of grain boundary resistance R_(gb) becomes more prominent compared to grain resistance R_(b) at room temperature,and with the increase in T_(SM),R_(gb) decreases faster than the intrinsic R_(b).The frequency response of the imaginary part of impedance showed relaxation behavior at every T_(SM),and the relaxation frequency variation with T_(SM) appeared to be of Arrhenius nature and the activation energy has been estimated to be 0.37 eV.A complex modulus spectrum was used to understand the mechanism of the electrical transport process,which indicated that a non-Debye type of conductivity relaxation characterizes this material.

关键词： ferrimagnetic ceramics impedance spectroscopy electric modulus temperature dependence

Computational study of combined effects of conduction-radiation and hydromagnetics on natural convection flow past magnetized permeable plate

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Applied Mathematics and Mechanics(English Edition) 2012年第6期33卷 731-748页

作者： M.ASHRAF S.ASGHAR M.A.hossain Department of Mathematics COMSATS Institute of Information Technology Department of Mathematics King Abdulaziz University Department of Mathematics University of Dhaka

The computational study of the combined effects of radiation and hydro- magnetics on the natural convection flow of a viscous, incompressible, and electrically conducting fluid past a magnetized permeable vertical plate is presented. The governing non-similar equations are numerically solved by using a finite difference method for all values of the suction parameter and the asymptotic solution for small and large values of ~. The effects of varying the Prandtl number Pr, the magnetic Prandtl number Prm, the magnetic force parameter S, the radiation parameter Rd, and the surface temperature Ow on the coefficients of the skin friction, the rate of heat transfer, and the current density are shown graphically and in tables. An attempt is made to examine the effects of the above mentioned physical parameters on the velocity profile, the temperature distribution, and the transverse component of the magnetic field.

关键词： hydromagnetic fluctuating natural convection magnetized plate currentdensity heat transfer

Reproductive health and rights in the COVID-19 era:Why and how are rights and choices still the answer?

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Asian pacific Journal of Reproduction 2022年第4期11卷 155-157页

作者： Md Anwer hossain Department of Population Sciences Faculty of Social SciencesUniversity of DhakaDhaka-1000Bangladesh

Amidst the coronavirus disease 2019(COVID-19)pandemic,the concern over the potential‘baby boom’or‘baby bust’had drawn renewed attention across the globe[1-3].However,historically alarmism over fertility rates gave rise to restrictive and coercive policies with an aim of‘controlling the population’that violated people’s sexual and reproductive health and rights(SRHR).In this perspective,the author argued that whether countries of the world face a COVID-19-induced short-term baby boom or bust,the solution lies in prioritizing the rights and choices of all people,especially their SRHR;not in adopting target-oriented population policies or coercive family planning programs.

关键词： priori fertility choice

Salt-Induced Changes in Physio-Biochemical and Antioxidant Defense System in Mustard Genotypes

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Phyton-International Journal of Experimental Botany 2020年第3期89卷 541-559页

作者： Md.Shakhawat hossain Md.Daud hossain Abdul Hannan Mirza Hasanuzzaman Md.Motiar Rohman Central Laboratory Research WingBangladesh Agricultural Research InstituteGazipur 1701Bangladesh Seed Technology Division Bangladesh Agricultural Research InstituteGazipur 1701Bangladesh Department of Agronomy Sher-e-Bangla Agricultural UniversityDhaka 1207Bangladesh Molecular Breeding Lab Plant Breeding DivisionBangladesh Agricultural Research InstituteGazipur 1701Bangladesh

Salinity stress is a major factor limiting plant growth and productivity of many crops including *** present study investigated the identification of salt tolerant mustard genotypes and better understanding the mechanism of salinity *** stresses significantly reduced relative water content(RWC),chlorophyll(Chl)content,K^(+) and K^(+)/Na^(+) ratio,photosynthetic rate(P N),tran-spiration rate(Tr),stomatal conductance(gs),intercellular CO_(2) concentration(Ci)and increased the levels of proline(Pro)and lipid peroxidation(MDA)contents,Na+,superoxide(O_(2)^(•−))and hydrogen peroxide(H_(2)O_(2))in both tolerant and sensitive mustard *** tolerant genotypes maintained higher Pro and lower MDA content than the salt sensitive genotypes under stress *** activities of superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),glutathione peroxidase(GPX),monodehydroascorbate reductase(MDHAR)and dehydroascorbate reductase(DHAR)were increased with increasing salinity in salt tolerant genotypes,BJ-1603,BARI Sarisha-11 and BARI Sarisha-16,but the activities were unchanged in salt sensitive genotype,BARI ***,the increment of ascorbate peroxidase(APX)activity was higher in salt sensitive genotype as compared to tolerant ***,the activ-ities of glutathione reductase(GR)and glutathione S-transferase(GST)were increased sharply at stress conditions in tolerant genotypes as compared to sensi-tive *** accumulation of Pro along with improved physiological and biochemical parameters as well as reduced oxidative damage by up-regulation of antioxidant defense system are the mechanisms of salt tolerance in selected mustard genotypes,BJ-1603 and BARI Sarisha-16.

关键词： Mustard saline sensitivity photosynthesis antioxidants ionic imbalance oxidative stress

Responses in gas exchange and water status between drought-tolerant and-susceptible soybean genotypes with ABA application

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The Crop Journal 2015年第6期3卷 500-506页

作者： Md.Mokter hossain Hon-Ming Lam Jianhua Zhang School of Life Sciences and Center for Soybean Research of the State Key Laboratory of Agrobiotechnology The Chinese University of Hong Kong

The purpose of this study was to investigate the physiological responses of drought-tolerant and drought-susceptible soybean genotypes to exogenous abscisic acid(ABA) application during progressive soil drying at seedling stages. Five-day old soybean seedlings were transplanted into PVC tubes filled with soil mixture. Seedlings were watered daily with similar water volumes until second trifoliate leaves emerged, and thereafter soil drying with or without exogenous ABA application was imposed. Half of the seedlings of each genotype were left for regular watering as control plants. Soil water status declined significantly over seven days of withholding water supply for both genotypes. Leaf expansion rate, stomatal conductance(g_s), leaf water potential(ψ_w), and relative water content of leaves(%RWC) declined significantly under soil drying as well as soil drying with ABA application, compared to their values for well-watered soybean genotypes. However, a drought-tolerant genotype(C12) responded more rapidly than a drought-susceptible genotype(C08) after imposition of soil drying and soil drying with exogenous ABA. In addition, application of exogenous ABA to water-restricted soybeans resulted in higher %RWC and ψwin the drought-tolerant than in the drought-susceptible genotype. Compared to the drought-susceptible genotype, the drought-tolerant genotype was more responsive to exogenous ABA application, resulting in a higher root-to-shoot ratio.

关键词： Drought stress Exogenous ABA Leaf relative water content Stomatal conductance Soybean genotypes

Numerical Modelling of Proppant Transport in Hydraulic Fractures

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Fluid Dynamics & Materials Processing 2020年第2期16卷 297-337页

作者： Yatin Suri Sheikh Zahidul Islam Mamdud hossain School of Engineering Robert Gordon UniversityAberdeenUK

The distribution of proppant injected in hydraulic fractures significantly affects the fracture conductivity and well *** proppant transport in thin fracturing fluid used during hydraulic fracturing in the unconventional reservoirs is considerably different from fracturing fluids in the conventional reservoir due to the very low viscosity and quick deposition of the *** paper presents the development of a three-dimensional Computational Fluid Dynamics(CFD)modelling technique for the prediction of proppant-fluid multiphase flow in hydraulic *** proposed model also simulates the fluid leak-off behaviour from the fracture *** Euler-Granular and CFD-Discrete Element Method(CFD-DEM)multiphase modelling approach has been applied,and the equations defining the fluid-proppant and inter-proppant interaction have been solved using the finite volume *** proppant transport in hydraulic fractures has been studied comprehensively,and the computational modelling results of proppant distribution and other flow properties are in good agreement with the published experimental *** parametric study is performed to investigate the effect of variation in proppant size,fluid viscosity and fracture width on the proppant *** proppants can be injected early,followed by larger proppants to maintain high propping *** study has enhanced the understanding of the complex flow phenomenon between proppant and fracturing fluid and can play a vital role in hydraulic fracturing design.

关键词： Proppant transport hydraulic fracturing eulerian-granular model computational fluid dynamics discrete element method fluid leak-off

Breeding Potential of Some Exotic Tomato Lines:A Combined Study of Morphological Variability,Genetic Divergence,and Association of Traits

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Phyton-International Journal of Experimental Botany 2022年第1期91卷 97-114页

作者： Shafiul Islam Lutful Hassan Mohammad Anwar hossain Department of Genetics and Plant Breeding Bangladesh Agricultural UniversityMymensingh2202Bangladesh

Tomato(Solanum lycopersicum L.)is called‘the poor man’s orange’due to its low price and improved nutritional *** experiment was conducted to study the breeding potential of some exotic tomato lines by assessing various qualitative and quantitative traits conferring yield and quality *** the qualitative traits,greater variability was observed for growth type,stem hairiness,and fruit shape and size.A determinate growth habit was observed in the genotype AVTO9802 while the genotype AVTO0102 produced yellow color fruits.A significant(p≤0.01)variation was also observed for the studied quantitative *** on yield and traits attributed to yield,the genotypes AVTO0314,GPB0107,GPB0120 and AVTO9802 were selected as promising *** differences between the genotypic and phenotypic coefficients of variation(GCV and PCV)of the studied quantitative traits were very *** suggests that the apparent variation was mainly due to the *** higher GCVand PCV values were observed for the number of primary branches plant^(−1)(NPB),number of fruits cluster^(−1)(NFC),individual fruit weight(IFW)and total soluble solids(TSS).High heritability was recorded for all quantitative traits in a broad ***,the individual fruit diameter showed the highest heritability(99.56).The highest(102.75)genetic advance(GA)was observed for the number of fruits plant^(−1)(NFP).High heritability coupled with high GA as percentage of mean were recorded for the traits NFP,NFC,fruit yield plant^(−1)(FYP)and *** showed a significant positive correlation with NFC(0.714^(***))and a negative correlation with days to the first harvest(−0.539^(***))and plant height(−0.492**).Principal component analysis revealed that the first four components explained 78.5%of the total variation among the ***,the promising genotypes(AVTO0314,GPB0107,GPB0120,AVTO9802 and AVTO0102)isolated from this study can be used for developing high-yielding and high-quality tomato va

关键词： Tomato yield and quality traits genetic advance heritability correlation coefficient principal component analysis

Effects of rainfall patterns on runoff and rainfall-induced erosion

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International Journal of Sediment Research 2019年第3期34卷 270-278页

作者： Morteza Alavinia Farzin Nasiri Saleh hossain Asadi Department of Water Engineering Faculty of Civil and Environmental Engineering Tarbiat Modares University Department of Soil Science University of Tehran

Rainfall-induced erosion involves the detachment of soil particles by raindrop impact and their transport by the combined action of the shallow surface runoff and raindrop impact. Although temporal variation in rainfall intensity(pattern) during natural rainstorms is a common phenomenon, the available information is inadequate to understand its effects on runoff and rainfall-induced erosion processes. To address this issue, four simulated rainfall patterns(constant, increasing, decreasing, and increasing-decreasing) with the same total kinetic energy were designed. Two soil types(sandy and sandy loam)were subjected to simulated rainfall using 15 cm × 30 cm long detachment trays under infiltration conditions. For each simulation, runoff and sediment concentration were sampled at regular intervals. No obvious difference was observed in runoff across the two soil types, but there were significant differences in soil losses among the different rainfall patterns and stages. For varying-intensity rainfall patterns, the dominant sediment transport mechanism was not only influenced by raindrop detachment but also was affected by raindrop-induced shallow flow transport. Moreover, the efficiency of equations that predict the interrill erosion rate increased when the integrated raindrop impact and surface runoff rate were applied. Although the processes of interrill erosion are complex, the findings in this study may provide useful insight for developing models that predict the effects of rainfall pattern on runoff and erosion.

关键词： Rainfall pattern Sediment concentration Soil loss Sediment transport mechanisms

Time-Dependent Cylindrical and Spherical Solitary Structures and Double Layers of Dust Ion-Acoustic Waves in Ultra-Relativistic Dense Plasma

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Communications in Theoretical Physics 2013年第6期59卷 745-750页

作者： T.Akhter M.M.hossain A.A.Mamun Department of Physics Jahangirnagar University

Cylindrical and spherical (nonplanar) solitary waves (SWs) and double layers (DLs) in a multi-ion plasma system (containing inertial positively as well as negatively charged ions, non-inertial degenerate electrons, and negatively charged static dust) are studied by employing the standard reductive perturbation method. The modified Gardner (MG) equation describing the nonlinear propagation of the dust ion-acoustic (DIA) waves is derived, and its nonplanar SWs and DLs solutions are numerically analyzed. The parametric regimes for the existence of SWs, which are associated with both positive and negative potential, and DLs which are associated with negative potential, are obtained. The basic features of nonplanar DIA SWs, and DLs, which are found to be different from planar ones, are also identified.

关键词： solitary waves double layers ultra-relativistic dense plasma dust ion acoustic waves Gardnerequation