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Search Results: 1 - 10 of 12875 matches for " Ashif Muhammad and Md. Ariful Islam "
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Bishwajit Bokshi*, S.M. Abdur Rahman, S. Kumar Sadhu, Ashif Muhammad and Md. Ariful Islam
International Journal of Pharmaceutical Sciences and Research , 2013,
Abstract: ABSTRACT: The different fractions of crude methanol extract of stem of Stephania japonica (Thunb.) Miers (Menispermaceae) was screened for its analgesic and antidiarrhoeal activities. The different fractions of crude extract produced significant writhing inhibition in acetic acid induced writhing in mice at the dose of 250 and 500 mg/kg body weight comparable to the standard drug diclofenac sodium at the dose of 25 mg/kg of body weight. When tested for its antidiarrhoeal effects on castor oil induced diarrhea in mice, it increased mean latent period and decreased the frequency of defecation significantly at the dose of 250 and 500 mg/kg body weight comparable to the standard drug loperamide at the dose of 50 mg/kg of body weight. The overall results suggest the analgesic and anti diarrhoeal activities of the different fractions of crude extract. Among all the fractions Ethyl acetate soluble fraction showed most significant analgesic activity and Petroleum ether soluble fraction showed the most significant anti diarrhoeal activity.
A Modified and Secured RSA Public Key Cryptosystem Based on “n” Prime Numbers  [PDF]
Muhammad Ariful Islam, Md. Ashraful Islam, Nazrul Islam, Boishakhi Shabnam
Journal of Computer and Communications (JCC) , 2018, DOI: 10.4236/jcc.2018.63006
Abstract: Cryptography is the study that provides security service. It concerns with confidentiality, integrity, and authentication. Public key cryptography provides an enormous revolution in the field of the cryptosystem. It uses two different keys where keys are related in such a way that, the public key can use to encrypt the message and private key can be used to decrypt the message. This paper proposed an enhanced and modified approach of RSA cryptosystem based on “n” distinct prime number. This existence of “n” prime number increases the difficulty of the factoring of the variable “N” which increases the complexity of the algorithm. In this approach, two different public key and private key generated from the large factor of the variable “N” and perform a double encryption-decryption operation which affords more security. Experiment on a set of a random number provided that the key generation time, analysis of variable “N”, encryption and decryption will take a long time compared to traditional RSA. Thus, this approach is more efficient, highly secured and not easily breakable.
Unsteady Heat Transfer of Viscous Incompressible Boundary Layer Fluid Flow through a Porous Plate with Induced Magnetic Field  [PDF]
Ariful Islam, Muhammad Minarul Islam, Mahabur Rahman, Lasker Ershad Ali, Md. Shakhaoath Khan
Journal of Applied Mathematics and Physics (JAMP) , 2016, DOI: 10.4236/jamp.2016.42037
Abstract: Because of the great importance of thermal instability in nature, in chemical processes, in separation processes, in industrial applications as well as in geophysical and astrophysical engineering, the effect of thermal diffusion on the combined MHD heat transfer in an unsteady flow past a continuously moving semi-infinite vertical porous plate which is subjected to constant heat has been investigated numerically under the action of strong applied magnetic field taking into account the induced magnetic field. This study is performed for cooling problem with lighter and heavier particles. Numerical solutions for the velocity field, induced magnetic field as well as temperature distribution are obtained for associated parameters using the explicit finite difference method. The obtained results are also discussed with the help of graphs to observe effects of various parameters on the above mentioned quantities.
Efficacy and Economics of Different Need Based Nitrogen Management Approaches in Winter Rice  [PDF]
Nilufar Akhtar Jahan, Sabina Yeasmin, Md. Parvez Anwar, Md. Ariful Islam, Hamidur Rahman, A. K. M. Mominul Islam
American Journal of Plant Sciences (AJPS) , 2018, DOI: 10.4236/ajps.2018.913189
Abstract: This experiment aimed to study the efficacy of different nitrogen (N) management approaches in winter rice. The experiment consisted of two rice varieties: 1) BRRI (Bangladesh Rice Research Institute) dhan29-an inbred and 2) Dhanigold-a hybrid, and eight N management approaches: 1) BRRI recommended N (control), 2) Soil analysis based N management, 3) N application based on Agro-ecological zone, 4) 20 kg·N·ha-1 at ≤35 SPAD (Silicon photon activate diode) value, 5) 30 kg·N·ha-1 at ≤35 SPAD value, 6) 20 kg·N·ha-1 at ≤3.0 LCC (leaf colour chart) value, 7) 30 kg·N·ha-1 at ≤3.0 LCC value and 8) Urea Super Granule. Between two varieties, hybrid Dhani gold produced higher grain yield (6.67 t·ha-1) than the inbred BRRI dhan29. Application of 20 kg·N·ha-1 at ≤3.0 LCC value gave the highest grain yield (7.10 t·ha-1), whereas the lowest grain yield (5.92 t·ha-1) was found from the SPAD approach with 20 kg·N·ha-1 at ≤35 SPAD value. In case of treatment interaction highest grain yield (7.34 t·ha-1) was found in BRRI dhan29 coupled with 20 kg·N·ha-1 at ≤3.0 LCC value with 18 kg·N·savings·ha-1 over control, maximum gross income (146,800 BDT·ha-1) and net benefit (142,120 BDT·ha-1), which was statistically identical with the grain yield from the interaction of Dhani gold and 30 kg·N·ha-1 at ≤3.0 LCC value but required 42 kg·extra·N·ha-1 (over control). The lowest grain yield (5.19 t·ha-1) was found when Dhanigold was coupled with 30 kg·N·ha-1 at ≤35 SPAD value, while the 20 kg·N·application·ha-1 at ≤35 SPAD value gave moderate yield (6.87 t·ha-1) with considerable higher gross (139,600 BDT·ha-1) and net (136,090 BDT·ha-1) incomes than the control (gross: 121,000 and net: 115,600 BDT·ha-1). The results reveal that 20 kg·N·ha-1 at ≤3.0 LCC value appeared as the promising practice for inbred BRRI dhan29, and 30 kg·N·ha-1 at ≤35 SPAD value for hybrid Dhanigold in terms of yield, N use efficiency and economic benefit of winter rice.
Chemical Reaction and Thermal Diffusion Effects on Mass Transfer Flow through an Inclined Plate  [PDF]
Farjana Akter, Md. Manjiul Islam, Ariful Islam, Md. Shakhaoath Khan, Md. Saddam Hossain
Open Journal of Fluid Dynamics (OJFD) , 2016, DOI: 10.4236/ojfd.2016.61006
Abstract: A numerical investigation of boundary layer mass transfer flow through an inclined plate with the effect of chemical reaction and thermal diffusion is presented in this study. The governing partial differential equations (PDE) are transformed to a system of dimensionless non-similar coupled PDEs. The transformed, non-similar conservations equations (momentum balance equation, energy balance equation and concentration balance equation) are then solved using a numerical approach known as explicit finite difference method (EFDM). Basically EFDM introduced for the unsteadiness in the momentum, temperature, and concentration fluid fields is based on the time dependent fluid velocity, temperature and concentration of the boundary surface. During the course of discussion, it is found that the various parameters related to the problem influence the calculated resultant expressions. The computed numerical solution results for the velocity, temperature, and concentration distribution with the effect of various important dimensionless parameters (Grashof number, Modified Grashof number, Prandtl number, Schmidt number, Soret number, Dufour number, chemical reaction parameter and inclination parameter) entering into the problems are critically analyzed and discussed graphically. It can be seen that two physical phenomena chemical reaction and thermal diffusion can greatly effect on the boundary layer fluid flows through an inclined plate.
Cutting a Cornered Convex Polygon Out of a Circle
Syed Ishtiaque Ahmed,Md. Ariful Islam,Masud Hasan
Journal of Computers , 2010, DOI: 10.4304/jcp.5.1.4-11
Abstract: The problem of cutting a convex polygon P out of a piece of planar material Q with minimum total cutting length is a well studied problem in computational geometry. Researchers studied several variations of the problem, such as P and Q are convex or non-convex polygons and the cuts are line cuts or ray cuts. In this paper we consider yet another variation of the problem where Q is a circle and P is a convex polygon such that P is bounded by a half circle of Q and all the cuts are line cuts. We give two algorithms for solving this problem. Our first algorithm is an O(log n)-approximation algorithm with O(n) running time, where n is the number of edges of P. The second algorithm is a constant factor approximation algorithm with approximation ratio 6.48 and running time O(n3).
Cutting a Convex Polyhedron Out of a Sphere
Syed Ishtiaque Ahmed,Masud Hasan,Md. Ariful Islam
Computer Science , 2009,
Abstract: Given a convex polyhedron $P$ of $n$ vertices inside a sphere $Q$, we give an $O(n^3)$-time algorithm that cuts $P$ out of $Q$ by using guillotine cuts and has cutting cost $O((\log n)^2)$ times the optimal.
Performance Analysis of Optical Wireless Communication System Employing Neuro-Fuzzy Based Spot-Diffusing Techniques  [PDF]
Shamim Al Mamun, M. Shamim Kaiser, Muhammad R Ahmed, Md. Shafiqul Islam, Md. Imdadul Islam
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2048
Abstract: The spot-diffusing technique provides better performance compared to conventional diffuse system for indoor optical-wireless communication (OWC) system. In this paper, the performance of an OW spot-diffusing communication system using Neuro-Fuzzy (NF) adaptive multi-beam transmitter configuration has been proposed. The multi-beam transmitter generates multiple spots pointed in different directions, hence, forming a matrix of diffusing spots based on position of the receiver and receiver mobility. Regardless of the position of the transmitter and receiver, NF controller target the spots adaptively at the best locations and allocates optimal power to the spots and beam angle are adapted in order to achieve better signal-to-noise plus interference ratio (SNIR). Maximum ratio combining (MRC) is used in the imaging receiver. The proposed OW spot-diffusing communication system is compared with other spot-beam diffusion methods proposed in literature. Performance evaluation revels that the proposed NF based OW spot-diffusing communication system outperforms other spot-beam diffusion methods.
Chemical and Morphological Characteristics of Particulate Matter Suspended in the Air of the Dhaka University Area of Bangladesh  [PDF]
Muhammad Nurul Huda, Shahid Akhtar Hossain, Md Mominul Islam, Md Fakrul Islam
Open Journal of Air Pollution (OJAP) , 2018, DOI: 10.4236/ojap.2018.72005
Abstract: Total suspended particulate matter (SPM) in the urban atmosphere of Dhaka city was collected using a high volume sampling technique for a period of one month (August 2017-September 2017). Chemical characterization of particulate matter (PM) was investigated, and characterized concerning the size distribution, morphological features such as count, total area, average size, perimeter, circularity, aspect ratio (AR), roundness; equivalent spherical diameter (ESD), surface area and volume of PM. The results of elemental analysis showed that the presence of heavy metal in PM was ten to hundred times higher than the standard value prescribed by WHO and USEPA. Several morphological analysis indicated that particles varying in shape from nearly spherical to various irregular shape, had higher surface energy, higher content of Cl and S bearing particles and had a large surface area which can cause greater damage to lungs. The presence of various organic compounds containing functional groups like alcohols, ketones aldehydes, carboxylic acids as well as unsaturated and saturated carbon bonds was observed by FT-IR analysis. Scanning Electron Microscopy (SEM) was used to characterize the morphology of the PM. Agglomerates and shoots type particles were mostly seen in SPM.
Evaluation of Economical and Ecological Aspects of Denim Garments Dyeing with Fluorescent Dye  [PDF]
Muhammad Abdur Rashid, Md. Delwar Hossain, Muhammad Mufidul Islam, Md. Nakib-Ul-Hasan
Journal of Materials Science and Chemical Engineering (MSCE) , 2013, DOI: 10.4236/msce.2013.17001

In this study the existing process (3 steps) and proposed process (2 steps) were evaluated during dyeing of denim fabric with fluorescent dye. It compared the effectiveness of these two processes of fluorescent dyeing in the textile industry. Here at first the grey denim fabric was pretreated by scouring and bleaching. Then the fabric was dyed in existing process i.e. through catanizing, dyeing and binding at 10% and 15% shades. Again the pretreated fabric was dyed in proposed process i.e. through catanizing and (dyeing and binding) with same shades. Then the properties of two types of dyed fabric were compared. This study provides a set of experimental results, discussion and comparison between the two processes. The results show that the proposed process has less power and time consumption and more water savings compared to existing process. So the evaluation reflected that the proposed process was much more effective than existing process of denim dyeing with fluorescent dye.

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