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Search Results: 1 - 10 of 463212 matches for " Islam A "
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Precision Active Bridge Circuit for Measuring Incremental Resistance with ANN Compensation of Excitation Voltage Variation  [PDF]
Shakeb A. Khan, Tarikul Islam
Journal of Sensor Technology (JST) , 2011, DOI: 10.4236/jst.2011.13008
Abstract: The present work deals with the development of low cost, appreciably accurate precision electronic circuit for resistive sensor where measurement of the incremental resistance change with high degree of accuracy is essential. A linear and sensitive active half bridge circuit requiring only few components for its hardware implementation has been proposed for measuring very small resistance change due to change in physical quantity or chemical analytes. Theory of the proposed active bridge circuit has been discussed and experimental results have been compared with conventional bridge circuit. Initial measurements are made with Pt-100 Strain gauge sensor but it can be extended to other resistive sensors of practical importance. Results show that the active bridge circuit is almost four times more sensitive than conventional half bridge circuit and two times more sensitive than full Wheatstone bridge circuit. Studies have also been made to analyze the errors due to ambient temperature, connecting lead resistance and dc excitation voltage. Experimental results show that output of the circuit has negligible effect on ambient temperature and connecting lead resistance. The error due to excitation voltage has been compensated using Artificial Neural Network (ANN) based inverse modeling technique.
Study of Micro Grid Safety & Protection Strategies with Control System Infrastructures  [PDF]
Md Razibul Islam, Hossam A. Gabbar
Smart Grid and Renewable Energy (SGRE) , 2012, DOI: 10.4236/sgre.2012.31001
Abstract: Microgrids have been proposed in order to improve reliability and stability of electrical system and to ensure power quality of grid. Microgrid consists of low voltage distribution systems with distributed energy resources, such as wind turbine and photovoltaic power systems, together with storage devices. It is essential to protect a micro grid in both the grid-connected and the islanded mode of operation against all different types of faults. This paper describes micro grid protection and safety concept with central control and monitoring unit where multifunctional intelligent digital relay could be used. This central control & monitoring infrastructure is used for adaptive relay settings strategy for micro grid protection. Also operational safety design concept and fault mitigation technique is proposed to ensure confidence in protection system.
Effect of Gamma Irradiation Doses on Morphological and Biochemical Attributes of Grape Saplings  [PDF]
A. F. M. Saiful Islam, M. Muzahedul Islam, Md. Mehedi Hasan, Md. Mehedi Hasan
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.65050
Abstract: The demand of grape in Bangladesh is fulfilled through import from foreign countries. The fruits of local cultivars of grapes are sour and seeded. Development of seedless grape varieties having increased sweetness, higher yield with better nutritional quality is necessary to reduce the import dependency. The present research activities are the part of a grape improvement project. A pot experiment was conducted at the Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh, during June to November 2011 to determine the suitable gamma irradiation doses on growth, leaf area and biochemical characters of grape saplings. Three vegetative bud stages viz. bud initiation stage, 4-leaf stage and 8-leaf stage, and four doses of gamma irradiation viz. 0, 5, 10, and 15 Gy were used as treatments. The experiment was laid out in a Randomized Complete Block Design with four replications. Different irradiation doses and vegetative bud stages showed significant variations in respect of plant growth characters, leaf area, soluble protein and total sugar content. Interaction effects also had significant variations on most of the parameters studied. Higher doses of gamma irradiation had showed detrimental effect on grape saplings. Generally, increased in irradiation doses showed decreased and detrimental effects on most of the parameters under study. Maximum numbers and length of roots, total dry matter, leaf area and chlorophyll-a and chlorophyll-b content were found at 5 Gy irradiation dose. Total soluble protein and sugar content of leaf were found maximum at no irradiation and 15 Gy, respectively. Higher number of roots and length, total dry matter, leaf area, chlorophyll-a, and b and soluble protein content of leaf were observed at bud initiation stage while 8-leaf stage showed maximum total sugar of leaf. In the combined effect of gamma irradiation and vegetative bud stages, all parameters showed best results in 5 Gy with bud initiation stage except total sugar content of leaf.
CRITICAL ASSESSMENT OF THE DEGREE OF TEMPER EMBRITTLEMENT IN 2.25Cr-1Mo STEEL
M.A. Islam
Journal of Engineering and Applied Sciences , 2006,
Abstract: Reversible temper embrittlement has been frequently observed in many different low alloy steels, serving at high temperatures, due to segregation of trace elements at grain boundaries and/or carbide/matrix interfaces. This type of impurity element segregation can severely deteriorate the toughness and fatigue properties of the steel. In general, increase in the hardness and tensile strength also increases the fatigue life of the steel. So, fatigue lives of steels are sometimes assessed by these parameters. In this research work 2.25Cr-1Mo steel, before and after temper embrittlement, was characterized by microstructure observation, hardness measurement, tensile, fatigue and fracture toughness tests at room temperature in air. Experimental results revealed that temper embrittlement hardly modify the room temperature hardness values and tensile properties, although the fatigue and fracture behaviours of this steel are significantly changed.
Poultry Products Processing and Marketing System in Bangladesh
M.A. Islam
Pakistan Journal of Biological Sciences , 2003,
Abstract: This study has been discussed about the existing Poultry products processing and marketing system, its problems and its potential solutions in Bangladesh. Traditionally chickens are sold alive till today, because of lacking trust on slaughtering method (Halal or not), fear of disease or dead birds slaughtered, lack of processing and preserving technology and skill man power. Egg grading and packing has not yet been developed. Marketing system of it is in traditional. As a result producers are not getting remunerative price that is why middleman are being gainer. Therefore modern Poultry processing plant, preserving technology and proper marketing channels are suggested to establish.
Mechanical, Thermal and Interfacial Properties of Jute Fabric-Reinforced Polypropylene Composites: Effect of Potassium Dichromate  [PDF]
Jahangir A. Khan, Mubarak A. Khan, Rabiul Islam, Abdul Gafur
Materials Sciences and Applications (MSA) , 2010, DOI: 10.4236/msa.2010.16051
Abstract: Composites based on jute fabrics and polypropylene was fabricated by heat-press molding technique. The mechanical properties of the composites such as tensile strength, tensile modulus, bending strength, bending modulus and impact strength were measured in dependence of fiber contents. In order to improve fiber-matrix interaction, jute fabrics were treated with aqueous solutions of K2Cr2O7 (0.005-0.05% w/v). Composite prepared with 0.02% K2Cr2O7 treated jute fabrics showed the highest values of the mechanical properties. Thermogravimetric (TG/DTG) data of PP, jute fabrics and composites showed that thermal degradation temperatures of composites shifted to higher temperature regions compared to PP or jute fabrics. Treatment of jute fabrics improved the thermal stability of the composite considerably. Scanning electron microscopic images of tensile fractured sides of untreated and treated composites illustrated that better fiber-matrix interfacial interaction occurred in treated composite. The relative tendency of water absorption of both untreated and treated composites was also explored.
Random Crank-Nicolson Scheme for Random Heat Equation in Mean Square Sense  [PDF]
M. T. Yassen, M. A. Sohaly, Islam Elbaz
American Journal of Computational Mathematics (AJCM) , 2016, DOI: 10.4236/ajcm.2016.62008
Abstract: The goal of computational science is to develop models that predict phenomena observed in nature. However, these models are often based on parameters that are uncertain. In recent decades, main numerical methods for solving SPDEs have been used such as, finite difference and finite element schemes [1]-[5]. Also, some practical techniques like the method of lines for boundary value problems have been applied to the linear stochastic partial differential equations, and the outcomes of these approaches have been experimented numerically [7]. In [8]-[10], the author discussed mean square convergent finite difference method for solving some random partial differential equations. Random numerical techniques for both ordinary and partial random differential equations are treated in [4] [10]. As regards applications using explicit analytic solutions or numerical methods, a few results may be found in [5] [6] [11]. This article focuses on solving random heat equation by using Crank-Nicol- son technique under mean square sense and it is organized as follows. In Section 2, the mean square calculus preliminaries that will be required throughout the paper are presented. In Section 3, the Crank-Nicolson scheme for solving the random heat equation is presented. In Section 4, some case studies are showed. Short conclusions are cleared in the end section.
Automated Diabetic Retinopathy Detection Using Bag of Words Approach  [PDF]
Monzurul Islam, Anh V. Dinh, Khan A. Wahid
Journal of Biomedical Science and Engineering (JBiSE) , 2017, DOI: 10.4236/jbise.2017.105B010
Abstract:
Imaging and computer vision systems offer the ability to study quantitatively on human physiology. On contrary, manual interpretation requires tremendous amount of work, expertise and excessive processing time. This work presents an algorithm that integrates image processing and machine learning to diagnose diabetic retinopathy from retinal fundus images. This automated method classifies diabetic retinopathy (or absence thereof) based on a dataset collected from some publicly available database such as DRIDB0, DRIDB1, MESSIDOR, STARE and HRF. Our approach utilizes bag of words model with Speeded Up Robust Features and demonstrate classification over 180 fundus images containing lesions (hard exudates, soft exudates, microaneurysms, and haemorrhages) and non-lesions with an accuracy of 94.4%, precision of 94%, recall and f1-score of 94% and AUC of 95%. Thus, the proposed approach presents a path toward precise and automated diabetic retinopathy diagnosis on a massive scale.
Spectroscopic Investigation of Modified Single Wall Carbon Nanotube (SWCNT)  [PDF]
S Hussain, P Jha, A Chouksey, R Raman, S.S. Islam, T Islam, P.K Choudhary
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.26063
Abstract: We have investigated the effects of chemical treatment on Single Wall Carbon Nanotube (SWCNT) before and after being modified with HNO3/H2SO4 by Raman, FTIR and UV-Vis-NIR spectroscopy. The results show successful carboxylation of the CNT sidewalls as observed from FTIR and UV-Vis-NIR spectroscopy. This successful functionalization is achieved in 6-8 hrs of refluxing. We also report changes in the first and second order Raman spectra of SWNTs functionalized with oxygenated groups. During the experiment, we observe some important Raman features: Radial breathing mode (RBM), Tangential mode (G-band), and Disordered mode (D-band); which are affected due to the chemical oxidation of carbon nanotubes. We found that the ratio of D- to the G-band intensity (Id/Ig), increase after functionalization and the RBM mode in acid treated SWCNTs is almost disappeared.
On Line Measurement of Reactivity Worth of TRIGA Mark-II Research Reactor Control Rods  [PDF]
Nusrat Jahan, Mamunur M. Rashid, F. Ahmed, M. G. S. Islam, M. Aliuzzaman, S. M. A. Islam
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.29123
Abstract: The reactivity worth measurement system for control rods of the TRIGA MARK-II research reactor of Bangladesh has been design and developed. The theory of the kinetic technique of measuring reactivity has been used by this measurement system. The system comprises of indigenous hardware and software for online acquisition of neutron flux signals from reactor console and then computes the reactivity worth accordingly. Here for the TRIGA MARK-II research reactor, the reactivity measurement system was implemented with a dedicated circuit assembly and a conventional personal computer. A high-level Visual Basic real-time programming has been developed for data acquisition, reactivity calculation, online display (numerically as well as graphically), saving data, etc. To measure reactivity worth of TRIGA reactor control rods the rod drop experimental technique has been adopted. The results of tests experiments, carried out with the rod drop method for measuring various reactivity worth of control rods have been presented in the paper. A comparison between this results with the results using period method and that of computation method, demonstrated that the response of this reactivity measurement system is fast enough to monitor and measure the safety-related reactivity and power excursions in the reactor.
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