Browsing by Author "Islam, T."

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    A Double Inverted F-Shape Patch Antenna for Dual-Band Operation
    (Hindawi, 2014-04-27) Islam, M.M.; Faruque, M.R.I.; Hueyshin, W.; Mandeep, J. S.; Islam, T.
    A double inverted F-shape patch antenna is presented for dual-band operation. The proposed antenna is comprised of circular and rectangular slots on a printed circuit board of 40 mm × 40 mm × 1.6 mm with a 50 Ω microstrip transmission line. Commercially available high frequency structural simulator (HFSS) based on the finite element method (FEM) has been adopted in this investigation. It has a measured impedance bandwidths (2 : 1 VSWR) of 18.53% on the lower band and 7.8% on the upper band, respectively. It has achieved stable radiation efficiencies of 79.76% and 80.36% with average gains of 7.82 dBi and 5.66 dBi in the operating frequency bands. Moreover, numerical simulations have been indicated as an important uniformity with measured results. Full Text Link: http://dx.doi.org/10.1155/2014/791521
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    Enhancing the Performance of Lignocellulosic Textile Fabrics by Chemical Treatment and Filler Modification
    (Taylor and Francis Ltd., 2025-01-27) Khan, M.M.,; Rokonuzzaman, M.; Sayeed, A.; Islam, T.; Paul, D.; Moula, A.T.M.G.; Jahan, M.S.; Das, S.C.
    To improve the durability of lignocellulosic jute textiles, the raw woven fabric (plain weave) was treated with alkali and aloe vera solution. A coating of unsaturated polyester resin was employed to protect the jute textiles from outdoor environmental degradation. The initiator for the resin was methyl ethyl ketone peroxide (MEKP). To further improve the performance of the polyester-coated jute textiles, 10% Ca(OH)2 fillers were mixed with the resin. Hence, the developed jute textile samples were–J0 (raw jute textile), J1 (alkali and aloe vera treated and polyester resin-coated jute textile), and J2 [Ca(OH)2 filler-modified textiles of J1]. The physico-mechanical characteristics of all the jute textile samples were examined and evaluated via tensile, moisture, and water uptake performances. It was revealed that tensile breaking strength increased by 56% and 129% for J1 and J2 textiles, respectively, compared to the J0. The filler content samples (J2) also demonstrated an enhanced moisture resistance performance compared to J0. Further characterization was performed using FTIR (Fourier Transform Infrared) spectroscopy, TGA (Thermogravimetric Analysis), and SEM (Scanning Electron Microscopy) analysis. The aging test demonstrated improved properties for the modified jute textile samples in acidic and salt solutions, but weight loss occurred in alkaline solutions.
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    Fire retardant properties enhancement of cotton twill fabric using pumpkin (Cucurbita maxima) extract
    (Elsevier Ltd, 2022-03-17) Shikder, A.A.R.; Mamun, M.A.A.; Islam, T.; Khan, M.H.K.; Uddin, M.Z.
    Health hazards and environmental pollution are major concerns in present world. So, it is high time to think about ecofriendly and sustainable production. In this study, pumpkin juice has been used as an ecofriendly flame retardant finish to enhance the functionality of cotton twill fabric. The pumpkin juice extracted from the fresh pumpkin without any chemicals. The cotton fabric was treated with pumpkin juice in exhaust method. The treated and untreated samples were characterized by TGA, FTIR, SEM, and EDX. The flame-retardant property of the samples were evaluated based on the LOI and vertical flame tester. The result demonstrated that the treated samples exhibited high fire-retardant properties after being finished with pumpkin juice. The LOI value of the treated samples increased to 29 from 19 after treatment. The main reason behind the increased flammability is the dehydration of pumpkin juice-treated fabric which was clarified from the TG analysis. Moreover, the FTIR, SEM, and EDX report ensured the presence of bound and unbound water molecules, different salt, and several atoms in the samples treated with pumpkin juice that enhanced the protection against the spreading of the fire and thus improved fire-retardant properties of the treated samples.`
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    Mathematical Modelling for Heat Transfer of a Micropolar Fluid along a Permeable Stretching/Shrinking Wedge with Heat Generation/Absorption
    (IIETA, 2016-03) Alam, Shariful; Islam, T.; Uddin, Md. Jashim
    In this paper, we have developed a mathematical model for the problem of unsteady hydromagnetic two dimensional flow and heat transfer of a viscous incompressible micropolar fluid over a heated permeable linearly stretching/shrinking wedge with heat generation/absorption. A set of similarity parameters is employed to convert the governing nonlinear partial differential equations into ordinary differential equations which are solved numerically using Nachtsheim-Swigert shooting iteration technique along with sixth order Runge-Kutta integration scheme. Comparisons with previously published work are performed and the results are found to be in excellent agreement. Numerical results are presented through graphs and tables and discussed them from the physical point of view. It is observed that the local skin friction coefficient (rate of shear stress) increases with the increase of the magnetic field parameter and the rate of heat transfer increases with the increase of the heat generation parameter. Full Text Link: http://doi.org/10.18280/mmep.030101/