The University of Asia Pacific

Dhaka, Bangladesh

The University of Asia Pacific

Dhaka, Bangladesh
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Saeed T.,The University of Asia Pacific | Sun G.,Edith Cowan University
Critical Reviews in Environmental Science and Technology | Year: 2017

This paper provides a comprehensive review on organics and nutrients (N and P) removals from industrial, municipal, domestic, secondary treated, and decentralized wastewaters employing subsurface flow wetlands. The review indicates that novel operational strategies, structural modification, and internal carbon generation enhanced nitrogen and organics removals across such reviewed systems. Phosphorus removals were critically dependent on specific P-adsorbing materials. The review further illustrates that subsurface flow wetlands could meet reuse standards in decentralized clusters. Reasons and remedies of major operational problems (media clogging and seasonal variations) have also been analyzed. Different operational strategies have been identified to achieve higher removal rates. © 2017 Taylor & Francis Group, LLC.


Initial burst effect leading to poor drug loading is a major drawback associated with in situ implants. In order to address a solution to this problem the influencing factors need to be identified. The aim of this work was to study whether some important formulation variables, namely, lipophilicity/ hydrophilicity of drugs, different polymer types, polymer molecular weights and drug/ polymer ratios could influence initial drug burst with corresponding loading efficiency of in situ implants. Dexamethasone and dexamethasone phosphate were used as lipophilic and hydrophilic model drug, respectively. As a part of matrial characterization the thermal behavior of Dexamethasone, DL-PLA (Mw 28.6 kDa) and PLGA was studied by DSC and TGA. Dexamethasone and dexamethasone phosphate loaded DL-PLA (Mw 28.6 kDa and 11.7 kDa) and PLGA (Mw 12.9 kDa) implants with different drug/ polymer ratios (0.5:9.5, 1:9, 1.5:8.5, 2:8 and 3:7) were prepared in situ in phosphate buffer, pH 7.4. Lipophilic dexamethasone was found to be loaded more efficiently than hydrophilic dexamethasone phosphate. Drug loading efficiency with DL-PLA was found to be more than that with PLGA. Loading efficiency was found to increase with decreasing drug/ polymer ratios in formulation. Polymer molecular weight did not show any influence on loading efficiency. Extent of burst during implant formation, as measured by drug content analysis of aqueous buffer media, complemented drug loading efficiency of corresponding implant. Morphology of implant matrices, as studied by SEM, supported the experimental results. The types of drug, polymer and drug/ polymer ratios have profound influence on drug burst release and loadings in implants. Therefore, these factors can be manipulated to reduce the burst and improve loading efficiency of in situ implants.


Nipun T.S.,The University of Asia Pacific | Ashraful Islam S.M.,The University of Asia Pacific
Saudi Pharmaceutical Journal | Year: 2014

In the study, self emulsifying drug delivery system (SEDDS) of gliclazide, a poorly soluble drug, was developed and evaluated by in-vitro, ex-vivo and in-vivo techniques. Oil and surfactant were screened out according to their solubilizing capacity. Among the tested components Transcutol HP and Tween-80 showed good solubilizing capacity. These two components were used in different ratios to prepare gliclazide SEDDS. The SEDDS formulations were transparent and clear. Droplet size of the emulsion was determined by Laser Diffraction Technology of Malvern. Formulation F1 containing 1:1 (m/m) mixture of Transcutol HP/Tween-80 showed minimum mean droplet size (50.959. μm). In-vitro drug release from F1 was higher (99% within 20. min) than other formulations. The developed SEDDS was also evaluated for e. x-vivo permeability profile by using chicken intestinal sac. Formulation F1 showed optimal drug diffusion. In-vivo performance of SEDDS was evaluated in albino mice using plasma glucose level as a pharmacodynamic marker parameter. The test formulation (F1) showed significant reduction in plasma glucose level, after oral administration. So SEDDS may be an alternative technique for the oral administration of gliclazide. © 2013.


Sarker M.,The University of Asia Pacific
2016 3rd International Conference on Electrical Engineering and Information and Communication Technology, iCEEiCT 2016 | Year: 2017

Cognitive radio has become into a matter of great interest now-a-days for researchers as it opens a wide horizon of opportunities for maintaining the exponentially increasing bandwidth demand. In cognitive radio networks, Spectrum sensing is a major concerning issue for exploring dynamic spectrum management. This paper introduces an improved but simple continuous wavelet transform(CWT) based approach for efficient spectrum sensing of wideband channel, based on edge detection in which soft de-noising is utilized to suppress the noise level. One special feature of our approach is to use single scale transformation unlike most of the edge detection approach involves multi-scale transforms or product to suppress the noise as well as to detect edges properly which indicates frequency boundaries and identification of these edges is shown through simulation results. Performance of detection in low SNR region by our proposed method has also been improved than the conventional methods which is also illustrated through simulation result. © 2016 IEEE.


Fatemi M.N.,The University of Asia Pacific | Rahman T.,BDDL Housing LTD.
Urbani Izziv | Year: 2015

This study investigates the projected outcome of the Bangladesh government's decision to relocate the Hazaribagh tanneries outside Dhaka, the capital of Bangladesh. Ever since the early industrialisation of Bangladesh, leather processing industries have played a significant economic role. In Dhaka, these industries are mainly concentrated in Hazaribagh, an important area in the southwestern part of the city. Hazaribagh is a junction connecting the new township with the old one. However, the use of inferior technologies, coupled with the absence of proper industrial waste-management and waste-treatment facilities, have destroyed the ecology of the Hazaribagh area and badly impacted its surroundings. Consequently, moving the tanneries from Hazaribagh and then redeveloping the area offers a unique opportunity in the country's sustainable urban regeneration. Regenerating the Hazaribagh urban brownfield can serve as a model for sustainable twenty-first-century neighbourhoods, incorporating contemporary facilities and environmentally friendly elements for healthy living. This study analyses the Hazaribagh area's potential as an example of a planned sustainable area for the entire city, free from the severe pollution that it is notorious for.


Hassan M.Z.,The University of Asia Pacific | Song X.,University of British Columbia | Cheng J.,University of British Columbia
Journal of Optical Communications and Networking | Year: 2012

The average symbol error rate is studied for subcarrier intensity modulated wireless optical communication systems employing general order rectangular quadrature amplitude modulation. We consider three different turbulence channel models, i.e., the Gamma-Gamma channel, the K-distributed channel, and the negative exponential channel with different levels of turbulence. Closed-form error rate expressions are derived using a series expansion of the modified Bessel function. In addition, detailed truncation error analysis and asymptotic error rate analysis are also presented. Numerical results demonstrate that our series solutions are highly accurate and efficient. © 2009-2012 OSA.


Roy N.,The University of Asia Pacific | Tasnim S.,Stamford University Bangladesh | Mamun A.A.,Jahangirnagar University
Physics of Plasmas | Year: 2012

A rigorous theoretical investigation has been made on the formation of the nonlinear structures (viz., solitary waves, double layers) in a dusty electron-positron-ion plasma (containing inertialess degenerate electrons and positrons, cold, mobile, inertial ions, and negatively charged stationary dust). The pseudo potential method has been employed in this theoretical investigation. The basic features of the solitary waves and double layers, which are associated with positive ion dynamics and pressures of degenerate electrons and positrons, are identified. The co-existence of positive and negative solitary waves, and existence of either positive or negative double layers have been theoretically observed for certain range of different plasma parameters. The implications of our results in astrophysical compact objects have been briefly discussed. © 2012 American Institute of Physics.


Podder J.,Bangladesh University of Engineering and Technology | Rahman A.,The University of Asia Pacific
International Journal of Optics | Year: 2010

The solubility of potassium dihydrogen phosphate (KDP) was determined for five different temperatures. Metastable zone width of aqueous solutions of KDP saturated at different temperatures was determined by nucleation method in pure form and adding a well-known chelating agent ethylenediaminetetraacetic acid (0.5mol% EDTA). The induction period was measured, experiments were performed at selected degrees of supersaturation (C/C*), and the critical nucleation parameters like interfacial energy (σ) were calculated, based on the classical theory of nucleation. The structural and optical properties of the grown crystals have been investigated. FTIR analysis has been carried out to characterize the grown crystals. Band gap has been calculated from transmission spectra. Copyright © 2010 Anisur Rahman and Jiban Podder.


Rahman A.,The University of Asia Pacific | Podder J.,Bangladesh University of Engineering and Technology
Indian Journal of Physics | Year: 2012

The pure ammonium dihydrogen phosphate (ADP) and ethylenediamine tetra acetic acid (EDTA) added ADP crystals were grown by isothermal evaporation method. The solubility of ADP was determined for five different temperatures. Metastable zone width of aqueous solutions of ADP saturated at different temperatures was determined by nucleation method in pure form and adding with 0.5 mol.% EDTA. The induction period τ was measured and experiments were performed at selected degrees of supersaturation (C/C*) and the critical nucleation parameters like interfacial energy (σ), energy of formation of the critical nucleus (ΔG*) were calculated based on the classical theory of nucleation. The grown crystals have been subjected to study the structural, optical and mechanical properties. FTIR analysis has been carried out to characterize the grown crystals. The transmission spectra from (100) planes of the grown crystals show that the transmission increases from 55.86 to 83.23% due to addition of EDTA in the visible region and band gap was found to increase from 1.31 to 1.41 eV. The microhardness test was carried out on (100) plane. The load dependent hardness and work hardening coefficient were measured. © 2012 Indian Association for the Cultivation of Science.


Sarker M.,The University of Asia Pacific
Proceedings of the 2016 IEEE International Conference on Wireless Communications, Signal Processing and Networking, WiSPNET 2016 | Year: 2016

Cognitive radio is now come into attention for researchers as a new solution to face the challenge of the fast growing bandwidth demand. Spectrum sensing is a major problem for dynamic spectrum management in cognitive radio networks. This paper introduces a simple Hilbert transform based approach for efficient spectrum sensing of wideband channel in which soft de-noising is used to suppress the noise level. In this approach the effect of noise is suppressed first by averaging PSD of the received signal then de-noised by soft thresholding. Frequency boundaries of bands are found more accurately by Hilbert transform which is shown in simulation result so it will also ease to characterize by vacant or occupied by determining the average PSD of the consecutive bands. Our proposed method has also improved performance of detection in low SNR region than the conventional methods which is also portrayed by simulation result. © 2016 IEEE.

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