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Search Results: 1 - 10 of 403119 matches for " M. Saifur Rahman "
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A perturbation technique to compute initial amplitude and phase for the Krylov-Bogoliubov-Mitropolskii method
M. Saifur Rahman
Tamkang Journal of Mathematics , 2012, DOI: 10.5556/j.tkjm.43.2012.563-575
Abstract: Recently, a unified Krylov-Bogoliubov-Mitropolskii method has been presented (by Shamsul cite{1}) for solving an $n$-th, $n=2$ or $n>2$, order nonlinear differential equation. Instead of amplitude(s) and phase(s), a set of variables is used in cite{1} to obtain a general formula in which the nonlinear differential equations can be solved. By a simple variables transformation the usual form solutions (i.e., in terms of amplitude(s) and phase(s)) have been found. In this paper a perturbation technique is developed to calculate the initial values of the variables used in cite{1}. By the noted transformation the initial amplitude(s) and phase(s) can be calculated quickly. Usually the conditional equations are nonlinear algebraic or transcendental equations; so that a numerical method is used to solve them. Rink cite{7} earlier employed an asymptotic method for solving the conditional equations of a second-order differential equation; but his derived results were not so good. The new results agree with their exact values (or numerical results) nicely. The method can be applied whether the eigen-values of the unperturbed equation are purely imaginary, complex conjugate or real. Thus the derived solution is a general one and covers the three cases, i.e., un-damped, under-damped and over-damped.
Harmonic Balance Solution of Mulholland Equation
M. Saifur Rahman,M. Alal Hosen,M. Shamsul Alam
Lecture Notes in Engineering and Computer Science , 2011,
Effect of Some Integrated Pest Management (IPM) Packages Against Brinjal Shoot and Fruit Borer and its Consequence on Yield
Md. Saifur Rahman,M. Zinnatul Alam,Mainul Haq,Nasreen Sultana
Journal of Biological Sciences , 2002,
Abstract: A study was conducted to evaluate the comparative effectiveness of three IPM packages on the basis of infestation level of brinjal shoot and fruit borer on shoots and fruits of eggplant. The IPM package 1 consisting of mechanical control on grafted eggplant; IPM package 2 comprising kerosene, neem oil and wild Ipomoea extract application on non-grafted eggplant; IPM package 3 containing Cymbush application on grafted eggplant and untreated plants. The grafted plants treated with Cymbush resulted significantly lowest shoot and fruit infestation compared to those of other treatments. Significantly the highest yield was obtained in plants treated with Cymbush. IPM packages with grafted plants produced more fruits than non-grafted ones. The diameter and weight of individual fruit was higher in plants under IPM package 1 and 3 utilizing grafted eggplant in late fruiting stage.
Length-weight Relationship, Condition Factor and Harvesting Records of Silver Pomfret (Pampus argenteus) in the Southwestern Region of Bangladesh
M. Saifur Rahman,M. Aminur Rahman,M. Rafiqur Rahman,Dipak Kamal
Pakistan Journal of Biological Sciences , 2004,
Abstract: The length-weight relationship and condition factor of silver pomfret, (Pampus argenteus), collected from the southwestern region of Bangladesh (Khulna, Bagerhat and Pirojpur) were studied for a period of twelve months. In total, 317 fish (sex combined) were sampled in monthly intervals. Standard length-weight relationship of P. argenteus was obtained to be Log W = -1.1004 + 2.7931 Log L. The co-efficient of correlation (r) was found to be 0.989. Standard errors of Sx and Sy were 2.955 and 8.287, respectively. The calculated t-test also indicated that the correlation between length and weight was significant. The mean value of condition factor (K) was found to be 44.27. The peak and lean harvesting volumes of this fish were recorded during the winter and summer months, respectively
Antinociceptive and Antioxidant Activities of the Dillenia indica Bark
M. Badrul Alam,M. Saifur Rahman,M. Hasan,M. Maruf Khan
International Journal of Pharmacology , 2012,
Abstract: Dillenia indica Linn. (Dilleniaceae) is widely used as food and reputed in the folk medicine of Bangladesh and India in particular, to relieve pain associated with gastrointestinal disturbance. Methanolic extract of the bark of Dillenia indica Linn. (MDI) was subjected to evaluate for its analgesic and antioxidant properties. The analgesic activity of MDI (200 and 400 mg kg-1 b.wt. p.o.) was determined for its central and peripheral pharmacological actions using hotplate as well as tail immersion method and acetic acid-induced writhing test with formalin induced pain in mice, respectively. To evaluate antioxidant potential of MDI, total antioxidant activity, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical as well as total Reactive Oxygen Species (ROS) and assessment of reducing power were used. The extract, at the dose of 200 and 400 mg kg-1, produced a significant (p<0.05) increase in pain threshold in hotplate and tail immersion methods whereas significantly (p<0.05) reduced the writhing caused by acetic acid and the number of licks induced by formalin in a dose dependent manner. In DPPH and total ROS scavenging method, MDI showed good antioxidant potentiality with the IC50 value of 12.32±0.16 and 34.72±0.48 μg mL-1, respectively with a good reducing power. The findings of the study suggested that MDI has strong analgesic and antioxidant effects, conforming the traditional use of this plant for pain alleviation to its antioxidant potentiality.
Effect of 3 mol% Yttria Stabilized Zirconia Addition on Structural and Mechanical Properties of Alumina-Zirconia Composites  [PDF]
M. A. Gafur, Md. Saifur Rahman Sarker, Md. Zahangir Alam, M. R. Qadir
Materials Sciences and Applications (MSA) , 2017, DOI: 10.4236/msa.2017.87041
Abstract: Alumina-Zirconia (Al2O3-ZrO2) composites especially Zirconia Toughened Alumina (ZTA) shows better mechanical properties over alumina. Al2O3-ZrO2 composites were prepared by powder compaction method varying 3 mol% yttria stabilized zirconia (3Y-ZrO2) content from 0 to 20 vol% using small amount of MgO as sintering aid. The composites were sintered for two hours in air at 1580°C. At this temperature maximum density was achieved 99.31% of theoretical density for composite containing 20 vol% 3Y-ZrO2. Density measurement of sintered composites was carried out using Archimedes’s method. Hardness and fracture toughness measurement was carried out using Vickers indentation. Phase content and t-ZrO2 retention were detected by means of X-ray diffraction (XRD). Microstructure of the composites and grain size of alumina and zirconia was determined by Scanning Electron Microscopic (SEM) analysis. Maximum microhardness (17.46 GPa) was achieved for composite containing 5 vol% ZrO2 and maximum flexural strength (684.32 MPa) and fracture toughness (10.33 MPam0.5) was achieved for composite containing 20 vol% of 3Y-ZrO2. The aim of the present work is to investigate the optimum 3Y-ZrO2 content for obtaining maximum density, microhardness, flexural strength and fracture toughness of Al2O3-ZrO2 composites.
Smart Grid Networks: Promises and Challenges
Abdulrahman Yarali,Saifur Rahman
Journal of Communications , 2012, DOI: 10.4304/jcm.7.6.409-417
Abstract: Integration of information and communication technologies with the traditional of electric power infrastructures and creation of an interoperable, scalable, and flexible smart grid will require numerous technological innovations and advancements. The purpose of this paper is to take a detailed look at the various technologies which may be utilized in the data transmission for the smart grid and the problems or difficulties that must be overcome to effectively use them. A variety of wireless systems are analyzed and we discuss the security of these mediums as privacy remains a major obstacle for implementing smart grid technology.
Changing Domesticity of Aedes aegypti in Northern Peninsular Malaysia: Reproductive Consequences and Potential Epidemiological Implications
Rahman G. M. Saifur, Hamady Dieng, Ahmad Abu Hassan, Md Rawi Che Salmah, Tomomitsu Satho, Fumio Miake, Ahmad Hamdan
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0030919
Abstract: Background The domestic dengue vector Aedes aegypti mosquitoes breed in indoor containers. However, in northern peninsular Malaysia, they show equal preference for breeding in both indoor and outdoor habitats. To evaluate the epidemiological implications of this peridomestic adaptation, we examined whether Ae. aegypti exhibits decreased survival, gonotrophic activity, and fecundity due to lack of host availability and the changing breeding behavior. Methodology/Principal Findings This yearlong field surveillance identified Ae. aegypti breeding in outdoor containers on an enormous scale. Through a sequence of experiments incorporating outdoors and indoors adapting as well as adapted populations, we observed that indoors provided better environment for the survival of Ae. aegypti and the observed death patterns could be explained on the basis of a difference in body size. The duration of gonotrophic period was much shorter in large-bodied females. Fecundity tended to be greater in indoor acclimated females. We also found increased tendency to multiple feeding in outdoors adapted females, which were smaller in size compared to their outdoors breeding counterparts. Conclusion/Significance The data presented here suggest that acclimatization of Ae. aegypti to the outdoor environment may not decrease its lifespan or gonotrophic activity but rather increase breeding opportunities (increased number of discarded containers outdoors), the rate of larval development, but small body sizes at emergence. Size is likely to be correlated with disease transmission. In general, small size in Aedes females will favor increased blood-feeding frequency resulting in higher population sizes and disease occurrence.
Evaluation of antimicrobial and cytotoxic properties of Leucas aspera and Spilanthes paniculata
M Alam Morshed 1* , Azim Uddin 1 , Rahman Saifur 2 , Anik Barua 3 , Anwarul Haque 2, 4
International Journal of Biosciences , 2011,
Abstract: Plants are rich source of antibacterial agents, which could be exploited in human disease management. The main aim of this study was to find out the antibacterial and cytotoxic activity of the n-hexane, ethyl acetate and ethanol extract of Leucas aspera and the ethanol fraction of chloroform, methanol and ethanol extract of Spilanthes paniculata were studied. The fraction and extracts of S. paniculata showed potential antimicrobial activities against 14 strains of microorganisms whereas L. aspera did not show any antimicrobial response. For antimicrobial test, Disc diffusion technique was used against five Gram positive and eight Gram negative bacteria and one fungi. The zone of inhibition of microorganisms was measured in mm. In vitro cytotoxicity test was also studied with both of the plants by Brine Shrimp Lethality Bioassay and results illustrated significant (p<0.05) cytotoxicity against A. salina, that were expressed as LC50.
Fuzzy Small Submodule and Jacobson -Radical
Saifur Rahman,Helen K. Saikia
International Journal of Mathematics and Mathematical Sciences , 2011, DOI: 10.1155/2011/980320
Abstract: Using the notion of fuzzy small submodules of a module, we introduce the concept of fuzzy coessential extension of a fuzzy submodule of a module. We attempt to investigate various properties of fuzzy small submodules of a module. A necessary and sufficient condition for fuzzy small submodules is established. We investigate the nature of fuzzy small submodules of a module under fuzzy direct sum. Fuzzy small submodules of a module are characterized in terms of fuzzy quotient modules. This characterization gives rise to some results on fuzzy coessential extensions. Finally, a relation between small -submodules and Jacobson -radical is established.
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