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Applied Mathematics 2020年第4期11卷 277-291页

作者： md.Enamul Karim md.abdus Samad Department of Applied Mathematics University of Dhaka Dhaka Bangladesh Department of Mathematics Comilla University Cumilla Bangladesh

The present study deals with the analysis of heat transfer of the unsteady Maxwell nanofluid flow in a squeezed rotating channel of a porous extensile surface subject to the velocity and thermal slip effects incorporating the theory of heat flow intensity of Cattaneo-Christov model for the expression of the energy distribution in preference to the classical Fourier’s law. A set of transformations is occupied to renovate the current model in a system of nonlinear ordinary differential equations that are numerically decoded with the help of MATLAB integrated function bvp4c. The effects of various flow control parameters are investigated for the momentum, temperature and diffusion profiles, as well as for the wall shearing stress and the heat and mass transfer. The results are finally described from the material point of view. A comparison of heat flux models of Cattaneo-Christov and Fourier is also performed. An important result from the present work is that the squeezing parameter is strong enough in the middle of the channel to retard the fluid flow.

关键词： Maxwell Fluid Model Squeezing Flow Elastico-Viscous Nanofluid Channel Rotation

Water Soluble Ionic Species in the Atmospheric Fine Particulate Matters (PM2.5) in a Southeast Asian Mega City (Dhaka, Bangladesh)

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Open Journal of Air Pollution 2015年第3期4卷 99-108页

作者： abdus Salam md. Assaduzzaman Muhammad Nobi Hossain A. K. M. Nur Alam Siddiki Department of Chemistry Faculty of Science University of Dhaka Dhaka Bangladesh

Atmospheric fine particulate matters (PM2.5) were collected with an Envirotech Instrument (Model APM 550) at the roof of Khundkur Mukarram Hussain Science Building, University of Dhaka, Bangladesh between January and February, 2013. PM2.5 samples were collected on Quartz fiber filters during day and night time. Water soluble ions (sulfate, nitrate, phosphate, chloride, bromide, sodium, potassium and calcium) were analyzed with Ion Chromatography (Model 881, Metrohm Ltd., Switzerland) and Flame photometer (Model PFP7, Jenway, UK). Average PM2.5 mass was 136.1 μg·mǅ during day time and 246.8 μg·mǅ during night time with a total average of 191.4 μg·mǅ. Nighttime PM2.5 concentration was about double compared than that of daytime presumable due to the low ambient temperatures with high emissions from heavy duty vehicles. The 24-hour average PM2.5 mass (average of day and night) was about eight times higher than WHO (25.0 μg·mǅ) and about three times higher than DoE, Bangladesh (65.0 μg·mǅ) limit values. The total average concentrations of sulfate, nitrate, phosphate, bromide, chloride, sodium, potassium and calcium were 5.30, 7.75, 0.62, 0.16, 1.19, 1.30, 8.11, and 3.09 μg·mǅ, respectively. The concentrations of the water soluble ions were much higher during nighttime than daytime except nitrate, bromide and potassium. Excellent correlations were observed between sulfate and nitrate, sodium and chloride, bromide and phosphate indicating joint sources of origin. Potassium, sulfate, nitrate and calcium are the most dominant species in PM2.5. Water soluble ionic components in Dhaka contributed about 15% mass of the PM2.5. Ratio analysis showed that sodium and chloride were from mainly sea salt. Potassium has varieties of sources other than biomass burning. Sulfate and nitrate are mainly from fossil fuel origin. This is the first study of the day and night variation of the water soluble ionic species at the fine particulate mat

关键词： Air Pollution Particulate Matters Water Soluble Ions Sulfate Nitrate

Synthesis, Spectral Characterization and Thermal Behavior of Newly Derived La(III), Co(III) and Mn(II) Complexes with Schiff Base Derived from Methionine and Salicylaldehyde

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Open Journal of Inorganic Chemistry 2018年第2期8卷 55-69页

作者： Shariful Islam A. K. M. Nur Alam Siddiki shahida Begum md. abdus Salam Department of Chemistry Faculty of Science University of Dhaka Dhaka Bangladesh

Many metal complexes of Schiff base derived from different amino acids are widely employed as biologically active materials, especially as antibacterial agents. Three new metal [Co(III), Mn(II) and La(III)] complexes with the Schiff base (L) derived from salicylaldehyde and amino acid (methionine) were synthesized and investigated by using various physico-chemical techniques such as elemental analysis, FTIR, UV-visible spectroscopy, magnetic measurement, thermo gravimetric analysis (TGA) and X-ray powder diffraction (XRD) method. From spectral studies, it has been concluded that the synthesized ligand acts as a tetra-dentate molecule, coordinates metal through azomethine nitrogen, sulfur, phenolic oxygen and carboxylate oxygen. UV-visible spectrophotometry showed the characteristic absorption bands corresponding to a square planar geometry for La(III) and Mn(II) metal complexes and tetrahedral geometry for Co(III) complex. The XRD data demonstrated that the manganese and cobalt complexes were crystalline but the lanthanum complex was amorphous in nature. The empirical formula of the synthesized complexes based on analytical data were [Co(C12H13SNO3)]·(NO3), [La(C12H13SNO3)](Cl)(H2O) and [Mn (C12H13SNO3)].

关键词： Schiff Base Metal Complexes Spectral Studies Thermal Behavior X-Ray Powder Diffraction

Design and Development of Innovative Highland Water Filtration System

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World Journal of Engineering and Technology 2016年第3期4卷 383-390页

作者： Mohd Hudzari Razali Syazili Roslan abdus Ssomad M. Abd Halim Ahmad Farizal md. Shokeri Nur Azuan Husin Faculty of Bioresources & Food Industry Universiti Sultan Zainal Abidin Tembila Campus Malaysia

The righteous book of Al-Quran mentions that the basic need of the living thing in this world is water. Resident of rural areas such as indigenous people will tap the highland aquatic resources as the main foundation for water. The reservoir is built on the top of hilly area to collect water before it discharges through a pipe system that uses the force of gravity to go down to the settlements. However, the filtration system frequently clogs and requires the occupants to climb up the reservoir hill for cleaning process. A lot of energy and time are required to manage the irrigation systems. Thus, an innovation system has been conducted as the filters will be cleaned automatically using solar energy supply. The designs of the filters are specially designed as the filter is equipped with electric motors, washer rods, power supply units, and automatic control box. The advantages of this project are the product will filtered the water as remain as natural highland watering resources while using the solar energy to accomplished green technology application.

关键词： Water Filtration Clogging and Foreign Material Solenoid Valve Relay Automation Solar Energy

Optical and electrical properties of crystalline indium tin oxide thin film deposited by vacuum evaporation technique

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Optoelectronics Letters 2019年第5期15卷 356-359页

作者： md.Mottaleb Hosen A.K.M.Atique Ullah md.Mahbubul Haque S.M.Abdur Rahim K.M.abdus Sobahan M.N.I.Khan Department of Electrical and Electronic Engineering Islamic University Kushtia 7003 Bangladesh Nanoscience and Technology Research Laboratory Atomic Energy Centre Bangladesh Atomic Energy Commission Dhaka 1000 Bangladesh Analytical Chemistry Laboratory Chemistry Division Atomic Energy Centre Bangladesh Atomic Energy Commission Dhaka 1000 Bangladesh Department of Physics Jagannath University Dhaka 1100 Bangladesh Materials Science Division Atomic Energy Centre Bangladesh Atomic Energy Commission Dhaka 1000 Bangladesh

Indium tin oxide(ITO) thin film was deposited on glass substrate by means of vacuum evaporation technique and annealed at 200 ℃, 300℃ and 400 ℃ in air for 1 h. The characterization and properties of the deposited film samples were analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM), and UV-VIS-NIR spectroscopy techniques. From the XRD patterns, it was found that the deposited thin film was of crystalline at an annealing temperature of 400℃. The crystalline phase was indexed as cubic structure with lattice constant and crystallite size of 0.511 nm and 40 nm, respectively. The SEM images showed that the films exhibited uniform surface morphology with well-defined spherical grains. The optical transmittance of ITO thin film annealed at 400 ℃ was improved from 44% to 84% in the wavelength range from 250 nm to 2 100 nm and an optical band gap was measured as 3.86 e V. Hall effect measurement was used to measure the resistivity and conductivity of the prepared film.

关键词： Indium tin oxide(ITO) X-ray diffraction(XRD) scanning electron microscopy(SEM)

Synthesis, spectral characterization and biological activities of Organotin(IV) complexes with <i>ortho</i>-vanillin-2-hydrazinopyridine (VHP)

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Open Journal of Inorganic Chemistry 2012年第2期2卷 22-27页

作者： Norrihan Sam md.Abu Affan md.abdus Salam Fasihuddin B. Ahmad Mohd Razip Asaruddin Department of Chemistry Faculty of Resource Science and Technology Universiti Malaysia Sarawak Kota Samarahan Malaysia

Five new organotin(IV) complexes of ortho-vanillin-2-hydrazinopyridine hydrazone with formula [RnSnCl4–n(VHP)] [R = Me2, n = 2 (2);R = Ph2, n = 2 (3);R= nBu2, n = 2 (4);R = nBu, n = 2 (5) and R = 1, n = 0 (6)] have been synthesized by direct reaction of ortho-vanillin-2-hydrazinopyridine hydrazone [(VHP), (1)], base and organotin(IV) chloride(s) in absolute methanol. The hydrazone ligand [(VHP), (1)] and its organotin(IV) complexes (2-6) have been characterized by UV-Visible, FT-IR and 1H NMR spectral studies. Spectroscopic data suggested that in the complexes (2-4), the ligand (1) acted as a neutral bidentate ligand and is coordinated to the tin(IV) atom via the azomethine nitrogen and pyridyl nitrogen atoms, whereas the ligand (1) acted as a uninegative tridentate ligand and coordinated to the tin(IV) atom through phenolic-O, azomethine-N and pyridyl-N atoms in complexes (5-6). The toxicity of the ligand (1) and its organotin (IV) complexes (2-6) were determined against Artemia salina. Organotin(IV) complexes showed moderate activity against Artemia salina. The ligand (1) and its organotin(IV) complexes (2-6) were also tested against four types of bacteria namely Bacillus cereus, Staphylococcus aureus, Escherichia coli and Enterobacter aerogenes. All organotin(IV) complexes and the free ligand (1) showed better antibacterial activities against bacteria. Among the organotin(IV) complexes (2-6), diphenyltin(IV) complex (3) showed higher activity against the four types of bacteria.

关键词： Hydrazone Organotin(IV) Complexes Spectral Analyses Toxicity Antibacterial Activity

Sustainable ifngerling production technique of endangeredLabeo calbasu (Hamilton, 1822) based on different protein levels in ponds

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Journal of Coastal Life Medicine 2017年第2期5卷 51-58页

作者： md.abdus Samad Shamol Chandra Barman Sujit Kumar Chatterjee md.Mustafizur Rahman Alok Kumar Paul Department of Fisheries University of RajshahiRajshahi-6205Bangladesh Fish Inspection and Quality Control Department of FisheriesDhakaBangladesh

Objective:To conduct on sustainable fingerling production technique of endangered Labeo calbasu (Hamilton, 1822) (L. calbasu) based on different protein levels in ponds. Methods: The experiment was carried out under rearing pond in fish hatchery complex with three treatments group each having three replicates under department of fisheries, University of Rajshahi.L. calbasu were stocked at 41990/ha in T1, T2 and T3, respectively. The initial length ofL. calbasu in three treatments were (4.60 ± 0.10) cm and initial weights were (3.48 ± 0.01) g. Fishes were fed with 28%, 30%, 32% protein supplement for T1, T2, T3, respectively. The fishes were initially fed at 10% of body weight on 1st and 2nd fortnight. Then it was decreased at 8% of body weight on 3rd and 4th fortnight. Finally in 5th fortnight they were fed 5% of body weight. The physico-chemical characteristics of pond water were measured fortnightly. Results: The mean final weight gain was found highest in T3 (40.87 ± 0.01) g which was significant compared to T1 and T2. SGR (% bwd–1) was found 2.83 ± 0.02 (T1), 3.04 ± 0.01 (T2) and 3.39 ± 0.01 (T3). The highest survival rate ofL. calbasu was found in T3 (90.00 ± 1.00) and the lowest was found in T1 (87.00 ± 1.00). The best FCR (1.54 ± 0.01) was observed in T3 fed with 32% protein supplement. The highest production was observed in T3 (1672.20 ± 16.96 kg/ha/75 days) and lowest was observed in T1(1055.50 ± 29.04 kg/ha/75 days). The highest net benefit was calculated in T3 (260663.00 ± 4326.88 tk.) and lowest was found in T1 (112831.00 ± 7383.66 tk.). The CBR was found 0.60 ± 0.04, 0.80 ± 0.02 and 1.16 ± 0.02 in T1, T2 and T3, respectively. There were significant differences in CBR values among the three treatments. Conclutions:In this study, growth parametersi.e., weight gain, SGR (% bwd–1), length gain, total yield were significantly (P < 0.05) improved in T3 treatment fed with 32% protein supplemented diets.

关键词： Fingerling Production Endangered Labeo calbasu Protein levels

Evaluation of alum precipitated formalin killed fowl cholera vaccine with immunologic response in ducks

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Evaluation of alum precipitated formalin killed fowl cholera...