Mawlana Bhashani Science and Technology University

About: Mawlana Bhashani Science and Technology University is a education organization based out in Dhaka, Bangladesh. It is known for research contribution in the topics: Photonic-crystal fiber & Cladding (fiber optics). The organization has 875 authors who have published 1173 publications receiving 10064 citations. The organization is also known as: Mawlana Bhashani Science & Technology University.

The removal of heavy metal ions from wastewater/aqueous solution using polypyrrole-based adsorbents: a review

Abstract: Water pollution caused by heavy metal ions is becoming a serious threat to human and aquatic lives day by day. Therefore, the treatment of heavy metal ions is of special concern for environmental scientists and engineers. Historically, various methods, such as physical and chemical precipitation, ion-exchange, reverse osmosis, membrane filtration, electrochemical treatment, solvent extraction, and adsorption, have been widely studied for the removal of these metal ions from aqueous/wastewater. However, over the past few decades, conducting polymer-based adsorbents have received considerable attention owing to their potential applications for different heavy metal ions especially Cr(VI), Zn(II), and Pb(II). Among the various conducting polymers, polypyrrole (PPy) based adsorbents play a major role for the removal of various heavy metal ions due to their ease of synthesis, biocompatibility and redox properties. The current review has mainly focused on the physico-chemical properties, adsorption characteristics and mechanism of different polypyrrole-based adsorbents, including PPy/biosorbents, PPy/Fe3O4 nanocomposites, PPy–polyaniline nanofibers, PPy–graphene nanocomposites, exfoliated PPy-organically modified clay nanocomposites, and hierarchical porous PPy-nanoclusters, as well as their applications towards the removal of heavy metal ions.

A Novel Approach for Spectroscopic Chemical Identification Using Photonic Crystal Fiber in the Terahertz Regime

Abstract: A novel highly sensitive porous core-photonic crystal fiber (PC-PCF) has been designed and analyzed for detection of chemical analytes in the terahertz frequency range. The PC-PCF is designed using rectangular structured air holes in the core with a kagome structured cladding. The full vectorial finite-element method is used to tune the geometrical parameters and to characterize the fiber. Our results demonstrate a high relative chemical sensitivity with significantly lower confinement loss for different analytes. Moreover, the PCF shows near zero dispersion variation, high modal effective area, high birefringence, and high numerical aperture. The practical realization of the fiber is feasible with present fabrication techniques. Our optimized PCF has commercial applications in chemical sensing as well as applications in terahertz systems that require guided polarization preserving transmission.

Spiral Photonic Crystal Fiber-Based Dual-Polarized Surface Plasmon Resonance Biosensor

Abstract: We numerically demonstrate a surface plasmon resonance biosensor-based on dual-polarized spiral photonic crystal fiber (PCF). Chemically stable gold material is used as the active plasmonic material, which is placed on the outer layer of the PCF to facilitate practical fabrication. Finite-element method-based numerical investigations show that the proposed biosensor shows maximum wavelength sensitivity of 4600 and 4300 nm/RIU in ${x}$ - and ${y}$ -polarized modes at an analyte refractive index of 1.37. Moreover, for analyte refractive index ranging from 1.33 to 1.38, maximum amplitude sensitivities of 371.5 RIU−1 and 420.4 RIU−1 are obtained in ${x}$ - and ${y}$ -polarized modes, respectively. In addition, the effects of changing pitch, different air hole diameter of the PCF and thickness of the gold layer on the sensing performance are also investigated. Owing to high sensitivity, improved sensing resolution and appropriate linearity characteristics, the proposed dual-polarized spiral PCF can be implemented for the detection of biological analytes, organic chemicals, biomolecules, and other unknown analytes.

Design of D-shaped elliptical core photonic crystal fiber for blood plasma cell sensing application

Abstract: In this research, the proposed design presents the compact sensing performances while infiltrating the blood fluid in the central hole of the D-shaped elliptical dual-core photonic crystal fiber (PCF) configuration. The properties such as index difference, coupling length, and transmission spectrum pertains the sensing property of the blood plasma cell. The proposed sensor can detect plasma by finite element method (FEM) which can be utilized to detect the variation of plasmon of light using plasma materials.

Surface Plasmon Resonance Based Titanium Coated Biosensor for Cancer Cell Detection

Abstract: A new optimized bowl-shaped mono-core surface plasmon resonance based cancer sensor is proposed for the rapid detection of different types of cancer affected cell. By considering the refractive index of each individual cancer contaminated cell with respect to their normal cell, some major optical parameters variation are observed. Moreover, the cancerous cell concentration is considered at 80% in liquid form and the detection method is finite element method with 2 100 390 mesh elements. The variation of spectrum shift is obtained by plasmonic band gap between the silica and cancer cell part which is separated by a thin (35 nm) titanium film coating. The proposed sensor depicts a high birefringence of 0.04 with a maximum coupling length of 66 $\mu$ m. However, the proposed structure provides an optimum wavelength sensitivity level between about 10 000 nm/RIU and 17 500 with a resolution of the sensor between 1.5 × 10−2 and 9.33 × 10−3 RIU. Also, the transmittance variance of the cancerous cell ranges from almost 3300 to 6100 dB/RIU and the amplitude sensitivity ranges nearly between −340 and −420 RIU $^{-1}$ for different cancer cells in major polarization mode with the maximum detection limit of 0.025. Besides, the overall sensitivity performance is measured with respect to their normal cells which can be better than any other prior structures that have already proposed.