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Search Results: 1 - 10 of 18484 matches for " Shahjahan Ali "
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Processing of Satellite Digital Images for Mapping Atmospheric Transmissivity in Bangladesh
Md Shahjahan Ali
International Journal of Information Technology and Computer Science , 2013,
Abstract: This study investigates the potential of determining atmospheric transmissivity (τ) from NOAA-AVHRR satellite images using a simple methodology. Using this method, hourly transmissivity values over the land surface area of Bangladesh has been determined. The spatio-temporal distribution of τ has been studied by constructing monthly average maps for the whole country for one complete year (February 2005 to January 2006). Yearly average map has been prepared by integrating monthly average maps. Geographical distribution of τ exhibits patterns and trends. It is observed that the value of τ varies from 0.3 to 0.65 with the average maximum value in the month of April and minimum value in the month of November. It is also observed that for western parts of the country, which is the drought prone area, transmissivity values are little bit higher than that at the eastern parts. Relatively lower values of τ in the dry months (November to January) may be due to the effect of particulate or chemical pollution in the atmosphere.
物理化学学报 , 2008,
Study of the Effect of Food Habit, Lifestyle and Daily Trip on Physical and Mental Status of Subjects at Islamic University in Kushtia, Bangladesh  [PDF]
Shahedur Rahman, Anowar Khasru Parvez, Abdus Sabur, Shahjahan Ali
Open Journal of Statistics (OJS) , 2012, DOI: 10.4236/ojs.2012.22027
Abstract: This is a qualitative (study that used framework analysis) to examine by interviews among University personnel who live inside and outside the Islamic University campus in Kushtia, Bangladesh. In the present study, we found that subjects who live inside of the University feel better physically and mentally than the nonresident subjects. It was found that residents are more fit and feel better during and after class time. Resident subjects have less stress and maintain balanced diet for which they have good average BMI value than the nonresident subjects. In addition nonresident subjects have suffered diseases comparatively much more than resident subjects.
Unsteady RANS and LES Simulation of an Ideal Rankine Vortex Decay
Md. Shahjahan Ali,Takashi Hosoda,Ichiro Kimura
Advances in Civil Engineering , 2012, DOI: 10.1155/2012/523839
Abstract: The 3D numerical simulation was carried out for an idealized Rankine vortex using nonlinear k-ε model (one kind of RANS model) and large eddy simulation (LES) techniques. In this 3D simulation, the vortex flow field was given to rotate with the vertical axis in a free surface rectangular domain. In order to investigate the predictability of standard (linear) and non-linear k-ε models, the decay of a trailing vortex was simulated and compared with previous DNS data. The governing equations for mean velocities and turbulent flows were discretized with the finite volume method based on a staggered grid system. It was observed that in the growth phase as well as in stabilized phase of turbulence, the decay rate of tangential velocity by RANS model was well comparable with LES simulation as well as previous DNS data. However, in the decay phase of turbulence, RANS model showed slightly faster decay of tangential velocity due to its slower decay of turbulence compared to LES or DNS. The patterns as well as magnitudes of secondary currents predicted by RANS and LES models were well comparable to each other. 1. Introduction The basic types of plane vortices can be classified into two categories: one with slower velocity at center and maximum at sides and the other with maximum at center and minimum velocity at edges. The rotary fluid motion of the first one is called the solid body rotation, since it is similar to the fluid motion filled in a rotating hollow box. On the other hand, if a long circular rod rotates in a fluid with constant velocity around its axis, the fluid velocity is found highest and equal to the velocity of rod at the rod’s surface (due to adhesion), and with increasing distance from the rod, the velocity is diminished in inverse proportional to the distance. Such a fluid motion is called a potential vortex. Fluid motion composed of a potential vortex and solid body rotation is called Rankine vortex (Figure 1) after the fluid dynamicist Rankine. The radial distance from the center to the maximum tangential velocity is called the radius of vortex core. For a steady circular motion without a velocity component normal to the plane of rotation, the Rankine vortex is the only possible vortex whose velocity is zero at the center as well as far away from it. In addition to these basic vortices, there are other time-dependent rotary motions that have azimuthal velocity component as well as radial and axial components. Figure 1: Velocity distribution in (a) solid body rotation, (b) potential vortex, and (c) Rankine vortex. The existence of such
Studies on Some Fixed Point Theorems in Terms of Metric and Banach Spaces
Md. Shahjahan Ali,Md.Rezaul Karim
Asian Journal of Information Technology , 2012,
Abstract: In this study we have studied the fixed-point theorem for two, three and Multi-valued Mappings into itself on a metric and Banach spaces.
Characterizations of Inner Product Spaces in Terms of Normed Linear Spaces
Md. Shahjahan Ali,Md.Rezaul Karim
Asian Journal of Information Technology , 2012,
Abstract: The great-celebrated theorem due to Jordan and Von-Neumann had revealed that an inner product could be obtained from a norm provided the norm satisfies the parallelogram law. We have also studied some other related theorems and corollaries deduced from Jordan and Von-Neumann.
物理化学学报 , 2007,
Medical Image Enhancement Using Morphological Transformation  [PDF]
Raihan Firoz, Md. Shahjahan Ali, M. Nasir Uddin Khan, Md. Khalid Hossain, Md. Khairul Islam, Md. Shahinuzzaman
Journal of Data Analysis and Information Processing (JDAIP) , 2016, DOI: 10.4236/jdaip.2016.41001
Abstract: Medical imaging includes different modalities and processes to visualize the interior of human body for diagnostic and treatment purpose. However, one of the most common degradations in medical images is their poor contrast quality and noise. The existence of several objects and the close proximity of adjacent pixels values make the diagnostic process a daunting task. The idea of image enhancement techniques is to improve the quality of an image. In this study, morphological transform operation is carried out on medical images to enhance the contrast and quality. A disk shaped mask is used in Top-Hat and Bottom-Hat transform and this mask plays a vital role in the operation. Different types and sizes of medical images need different masks so that they can be successfully enhanced. The method shown in this study takes a mask of an arbitrary size and keeps changing its size until an optimum enhanced image is obtained from the transformation operation. The enhancement is achieved via an iterative exfoliation process. The results indicate that this method improves the contrast of medical images and can help with better diagnosis.
A Simple Statistical Model to Estimate Incident Solar Radiation at the Surface from NOAA AVHRR Satellite Data
Mst. Ashrafunnahar Hena,M. Shahjahan Ali,M. Muntasir Rahman
International Journal of Information Technology and Computer Science , 2013,
Abstract: Processing of meteorological satellite image data provides a wealth of information useful in earth surface and environmental applications. Particularly, it is important for the estimation of different parameters of surface energy budget. In this work, a method has been developed to estimation of hourly incoming solar radiation on the surface of Bangladesh using NOAA-AVHRR satellite digital images. The model is based on the statistical regressions between the ground truth and satellite estimated values. Hundreds of full resolution images (1.1 km) for two months of the year have been processed using ERDAS IMAGINE software. Ground solar global irradiation for one place has been estimated for two months through this application. The efficiency of this method for calculating surface insolation has been checked by estimating the relative deviation between the estimated Irradiation and measured Irradiation. The method can be used for calculation of hourly irradiation over areas in a tropical environment.
Resistance Pattern of Ciprofloxacin Against Different Pathogens
Syeda Q. Ali,Ale Zehra,Baquar S. Naqvi,Shahjahan Shah
Oman Medical Journal , 2010,
Abstract: Objectives: Ciprofloxacin is a broad-spectrum antibiotic widely prescribed in clinical and hospital settings. The emergence of antimicrobial resistance against effective antibiotics is a global issue. The objective of study is the surveillance of ciprofloxacin against common pathogens.Methods: To investigate the present status of antimicrobial resistance against ciprofloxacin, five hundred and twenty four clinical isolates of Escherichia coli (30%), Staphylococcus aureus (33%), Salmonella typhi (9%), Klebsiella pneumonia (14%) and Pseudomonas aeruginosa (14%) were collected during study from January, 2008 to February, 2009 from different pathological laboratories running in and out side hospitals located in Karachi, Pakistan. These pathogens were isolated from specimens of both in and out patients. The in-vitro antimicrobial activity of ciprofloxacin was carried out by Disc Diffusion Method (Kirby-Bauer test).Results: Showed that ciprofloxacin is 27.02%, 21.95%, 16.66%, 72.22% and 44.44% resistant to Escherichia coli, Staphylococcus aureus, Salmonella typhi, Klebsiella pneumonia and Pseudomonas aeruginosa respectively.Conclusion: It is concluded that these clinical isolates have started developing resistance against ciprofloxacin due to its irrational and inappropriate use. Continuous surveillance is crucial to monitor the antimicrobial resistance among pathogens.
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