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Search Results: 1 - 10 of 6627 matches for " Md. Ashraful Islam Molla "
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Evaluation of Reaction Mechanism for Photocatalytic Degradation of Dye with Self-Sensitized TiO2 under Visible Light Irradiation  [PDF]
Md. Ashraful Islam Molla, Ikki Tateishi, Mai Furukawa, Hideyuki Katsumata, Tohru Suzuki, Satoshi Kaneco
Open Journal of Inorganic Non-metallic Materials (OJINM) , 2017, DOI: 10.4236/ojinm.2017.71001
Abstract: The dye-sensitized TiO2 method is one of the most promising methods for the visible-light-induced detoxification of pollutants. The reaction mechanism for photocatalytic degradation of orange II (OII) and rhodamine B (RhB) with self-sensitized TiO2 under visible light irradiation (λ > 400 nm) has been evaluated. Radical scavenger studies were carried out to investigate the active species involved in the photodegradation of 5 mg/L of initial concentration of OII and RhB at room temperature. The trapping effects of different scavengers results proved that the oxidation of OII and RhB mainly occurred by the direct oxidization of h+ and ·O2- radicals, while the ·OH radicals played only a relatively minor role in the direct oxidization process.
Thickness, Distribution and Quality Assessment of Gopalganj-Madaripur Peat Deposits: A Case Study of Potential Economic Opportunities in Mid-Eastern Low-Lying Bangladesh  [PDF]
Mrinmoy Kumar Maitra, Md. Ashraful Islam, Md. Al Mamun
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.59081
Abstract:

The present research work illustrates the extent, distribution and a generalized quality assessment of southern low-lying peat deposits in Madaripur and part of Gopalganj district that covers approximately 17,000 hectare areas. Based on the survey of 800 boreholes, drilled in this region at different times by several government and non-government organizations for the purposes of peat exploration and hydrogeological investigation, reveals that the study area is composed of a considerable amount of peat deposits in various localities among which the deposits at Baghia-Chanda beel in Madaripur and Gopalganj districts are the most remarkable. The average peat thickness (in-situ condition), studied during field investigation, is 6.5 feet for the upper peat deposits, overlying with an average of 3.5 feet of alluvium cover, followed by the lower peat layer of about 3 feet thick that begins at an average depth of 8 feet and separated by a thin bluish grey silty clay sediments from the upper one. The lower part of the study area, locally known as beels, is the most prospective region for peat, whereas the western part is less potential either having no peat intersection or minimal peat thickness. The overburden covers, on the other hand are inversely correlated with the peat thicknesses, i.e., thick overburden tend to correlate with thin peat deposits and the thickest peat intersections have no or minimal overburden. Due to the variation in bulk density and peat depth, this Holocene peat has an average of 59.10% carbon stock. Nitrogen levels, more than 3%, indicate that the peat developed from the decomposition of reeds, sedges, bushes and trunks of trees (higher in nitrogen) rather than either moss or grass (lower in nitrogen). Higher sulphur content (about 2.7%) reflected the influence of brackish environments where the formation of FeS2 took place in the roots of existing vegetation. The calorific values, about 1308.8 k-cal/kg (after 20% moisture reduction), suggest that the Gopalganj-Madaripur peat is a low grade fuel that can be used as an alternative energy source in the domestic and limited industrial purposes , to relatively expensive natural gas and

Financial Volatility Forecasting by Nonlinear Support Vector Machine Heterogeneous Autoregressive Model: Evidence from Nikkei 225 Stock Index
Md. Ashraful Islam Khan
International Journal of Economics and Finance , 2011, DOI: 10.5539/ijef.v3n4p138
Abstract: Support vector machines (SVMs) are new semi-parametric tool for regression estimation. This paper introduced a new class of hybrid models, the nonlinear support vector machines heterogeneous autoregressive (SVM-HAR) models and aimed to compare the forecasting performance with the classical heterogeneous autoregressive (HAR) models to forecast financial volatilities. It was observed through empirical experiment that the newly proposed hybrid (SVM-HAR) models produced higher predicting ability than the classical HAR model.
Hardware Virtualization Support In INTEL, AMD And IBM Power Processors
Kamanashis Biswas,Md. Ashraful Islam
Computer Science , 2009,
Abstract: At present, the mostly used and developed mechanism is hardware virtualization which provides a common platform to run multiple operating systems and applications in independent partitions. More precisely, it is all about resource virtualization as the term hardware virtualization is emphasized. In this paper, the aim is to find out the advantages and limitations of current virtualization techniques, analyze their cost and performance and also depict which forthcoming hardware virtualization techniques will able to provide efficient solutions for multiprocessor operating systems. This is done by making a methodical literature survey and statistical analysis of the benchmark reports provided by SPEC (Standard Performance Evaluation Corporation) and TPC (Transaction processing Performance Council). Finally, this paper presents the current aspects of hardware virtualization which will help the IT managers of the large organizations to take effective decision while choosing server with virtualization support. Again, the future works described in section 4 of this paper focuses on some real world challenges such as abstraction of multiple servers, language level virtualization, pre-virtualization etc. which may be point of great interest for the researchers.
Fast Algorithm of A 64-bit Decimal Logarithmic Converter
Ramin Tajallipour,Md. Ashraful Islam,Khan Wahid
Journal of Computers , 2010, DOI: 10.4304/jcp.5.12.1847-1855
Abstract: The paper presents an efficient algorithm to compute base-10 logarithm of a decimal number. The algorithm uses a 64-bit floating-point arithmetic, and is based on a digit-by-digit iterative computation that does not require look-up tables, curve fitting, decimal-binary conversion, or division operations. It is the first FPGA prototype of its kind that uses a 64-bit (decimal 16-digit) precision. Two numerical examples have been presented for the purpose of illustration. The algorithm produces very accurate result with a maximum absolute error of 3.53x10-14. The architecture is pipelined and implemented on to the Xilinx Virtex2p FPGA. It costs 6,752 logic cells, outputs at a minimum rate of 51 mega-samples/sec, and consumes 125.7 mW of power. The scheme is very suitable for timing and accuracy critical applications and compliant with the IEEE754-2008 standard (decimal64 format).
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.
Inside Productivity of Microcredit in Bangladesh: A Surgical Analysis
Md. Mahmudul Alam,Rafiqul Islam Molla
Asian Economic and Financial Review , 2012,
Abstract: Microcredit typically refers to petty collateral-free credits given to groups of poor members in the society for their socioeconomic emancipation. It is claimed to be an effective tool for enhancing income of the poor primarily through creation of self-employment opportunities for them in a variety of small economic activities. However, in this survey of microcredit borrowers in Bangladesh it is found that when self-employed family labor is paid wages at market rate, under the framework of economic-profit counting, economic productivity of credit for about 48 % of the borrowers is not enough to support payment of any interest. Similarly its social productivity in terms of job creation and women’s empowerment at family level is also found to be low and marginal. Even then about 90% of the borrowers prefer taking microcredit from microfinance institutions (MFIs) even at exorbitantly high interest rate, ostensibly to avoid compromising their socio-political rights and potentials at the hands of the local moneylenders or friends and relatives if credits are obtained from them. They see microcredit as a means of socio-political empowerment of the economically weak and underprivileged members of the society. As such they regard it as a more credible social than economic program.
Performance Evaluation of an Orthogonal Frequency Division Multiplexing based Wireless Communication System with implementation of Least Mean Square Equalization technique
Farhana Enam,Md. Arif Rabbani,Md. Ashraful Islam,Sohag Sarker
Mathematics , 2012,
Abstract: Orthogonal Frequency Division Multiplexing (OFDM) has recently been applied in wireless communication systems due to its high data rate transmission capability with high bandwidth efficiency and its robustness to multi-path delay. Fading is the one of the major aspect which is considered in the receiver. To cancel the effect of fading, channel estimation and equalization procedure must be done at the receiver before data demodulation. This paper mainly deals with pilot based channel estimation techniques for OFDM communication over frequency selective fading channels. This paper proposes a specific approach to channel equalization for Orthogonal Frequency Division Multiplex (OFDM) systems. Inserting an equalizer realized as an adaptive system before the FFT processing, the influence of variable delay and multi path could be mitigated in order to remove or reduce considerably the guard interval and to gain some spectral efficiency. The adaptive algorithm is based on adaptive filtering with averaging (AFA) for parameter update. Based on the development of a model of the OFDM system, through extensive computer simulations, we investigate the performance of the channel equalized system. The results show much higher convergence and adaptation rate compared to one of the most frequently used algorithms - Least Mean Squares (LMS).
Performance Evaluation of Wimax Physical Layer under Adaptive Modulation Techniques and Communication Channels
Md. Ashraful Islam,Riaz Uddin Mondal,Md. Zahid Hasan
Computer Science , 2009,
Abstract: Wimax (Worldwide Interoperability for Microwave Access) is a promising technology which can offer high speed voice, video and data service up to the customer end. The aim of this paper is the performance evaluation of an Wimax system under different combinations of digital modulation (BPSK, QPSK, 4 QAM and 16 QAM) and different communication channels AWGN and fading channels (Rayleigh and Rician). And the Wimax system incorporates Reed Solomon (RS) encoder with Convolutional encoder with half and two third rated codes in FEC channel coding. The simulation results of estimated Bit Error Rate (BER) displays that the implementation of interleaved RS code (255, 239, 8) with two third rated Convolutional code under BPSK modulation technique is highly effective to combat in the Wimax communication system. To complete this performance analysis in Wimax based systems, a segment of audio signal is used for analysis. The transmitted audio message is found to have retrieved effectively under noisy situation.
Functional Dyes
Ahmed El-Shafei,Ashraful Islam,Md. Akhtaruzzaman
Journal of Chemistry , 2013, DOI: 10.1155/2013/828910
Abstract:
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