Journal of Scientific Research <p>Published by the Faculty of Sciences, University of Rajshahi. Full-text articles available from <a title="Current issue of JSR" href="/index.php/JSR/issue/archive" target="_self">ARCHIVES</a>.</p> <p>Journal of Scientific Research is included on <a title="DOAJ" href="" target="_blank" rel="noopener">DOAJ</a>.</p> Faculty of Sciences, Rajshahi University en-US Journal of Scientific Research 2070-0237 <p>© Journal of Scientific Research</p><p><a href="" rel="license"><img src="" alt="Creative Commons License" /></a></p><p>Articles published in the "Journal of Scientific Research" are Open Access articles under a <span id="OBJ_PREFIX_DWT52_com_zimbra_url" class="Object"><a href="" target="_blank">Creative Commons Attribution-ShareAlike 4.0 International license</a> </span>(CC BY-SA 4.0). This license permits use, distribution and reproduction in any medium, provided the original work is properly cited and initial publication in this journal. In addition to that, users must provide a link to the license, indicate if changes are made and distribute using the same license as original if the original content has been remixed, transformed or built upon.</p> Common Fixed Point Theorems of Compatible Maps in Complex Valued <i>b</i>-Metric Spaces <p>In a paper Mukheimer established some results regarding common fixed point of two self mappings in a complex valued <em>b</em>-metric space satisfying a rational type contractive condition. In this paper we have established a common fixed point theorem by making use of compatibility and weak compatibility of self mappings satisfying generalized rational inequality of four mappings as opposed to two self mappings in a complex valued <em>b</em> – metric space. Some concrete examples have also been presented to verify the effectiveness and applicability of established results. Towards the end, an application to solution of Urysohn’s integral equations has also been presented to substantiate the usability of the obtained results. Results of this paper generalize the results of Mukheimer and some other earlier results. Theorems approved in this article will be supportable for researchers to work on rational contractions with more than two pair of self mappings. <strong>&nbsp;</strong></p> G. Yadav R. K. Sharma G. L. Prajapati ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 431 446 10.3329/jsr.v12i4.44374 Influence of Meteorological Variables on Atmospheric Electric Conductivity over an Urban Location <p>The measurements of atmospheric electric conductivity along with selected meteorological parameters was carried out at Bengaluru, an urban site in southern India (12.96° N, 77.56° E) during January-December 2015 to understand the electric nature of urban air.&nbsp; During the study period, well defined diurnal variation of conductivity was observed with higher values before sun rise and lower values during afternoon hours.&nbsp; For most of the fair weather days, variations in conductivity show a strong correlation with relative humidity and anti-correlation with ambient temperature. The monthly mean values of conductivity show highest values in winter and lowest in monsoon and interestingly a positive Pearson’s correlation coefficient of +0.5 was found between measured alpha ionization energy and atmospheric conductivity during the study period.</p> K. C. Kumar K. Nagaraja ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 447 453 10.3329/jsr.v12i4.45182 Thermo-luminescence Response of Carbon Nanotubes and Some Other Familiar TL Materials Using Medical LINAC <p>Strain and impurity defects in carbon nanotubes (CNTs) particularly their potentiality as a new TL material has been studied over the years. In this research, our main objective is to explore the suitability of using CNTs and its composites in the area of TL dosimeter. For this purpose, a study was carried out between the TL responses of the dosimeters TLD-100, TLD-7000 and NaI-LiF pellets. To carry out this research, equivalent irradiations were performed with these pellets using clinical linear accelerator (LINAC) under 6 <em>MV</em> X-ray photon beam. The dose range was from 0.5 to 5 Gy. During irradiation, the dose rate was kept constant at 300 MU/min. TLD reader was used to readout the samples in a flowing N<sub>2 </sub>atmosphere to reduce surface oxidation.During readout, pre-heat temperature was set initially at 50 °C, acquired&nbsp; temperature rate 10 °C/s and maximum annealed temperature was 300 °C. Response of TLD-100 under varying dose was typically linear for any doses but other dosimeters TLD-7000 showed supra-linearity beyond 2 Gy and NaI-LiF pellets showed sub-linearity response after 2 Gy. The TL glow peak of CNTs indicated that it was lying somewhere away from 300 °C.</p> N. A. Sohan M. J. Dewan A. K. M. M. Rahman M. Al-Mamun M. I. Hosan ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 455 462 10.3329/jsr.v12i4.45336 Fixed Point Theorem for Cyclic Weakly Generalized Contraction Mapping of Ciric Type <p>In this article, the concept of cyclic weakly generalized contraction mapping of Ciric type has been introduced and the existence of a fixed point for such mappings in the setup of complete metric spaces has been established. Result obtained extends and improves some fixed point results in the literature. Example is also given to show that class of contraction mappings introduced in the paper is strictly larger class than the class of mappings used in the literature and thus ensures wider applicability of the result by producing the solutions to new problems.</p> S. Goyal M. Garg ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 463 471 10.3329/jsr.v12i4.45501 Electronic States in a Doubly Eccentric Cylindrical Quantum Wire <p>Electronic states of a single electron in doubly eccentric cylindrical quantum wire are theoretically investigated in this paper. The motion of electron in quantum wire is free along axial direction in a cylindrical quantum wire and restricted in annular regions by three different parallel finite cylindrical barriers as soft wall confinement. The effective mass Schrödinger equation with effective mass boundary conditions is used to find energy eigenvalues and&nbsp;&nbsp; corresponding wavefunctions. Addition theorem for cylindrical Bessel functions is used to shift the origin for applying boundary conditions at different circular boundaries. Fourier expansion is applied after addition theorem to get wavefunctions in analytical form. A determinant equation is obtained as a result of applications of effective mass boundary conditions which roots gives energy of various electronic states. The lowest root gives ground state energy. The variation in ground state energy with eccentricity is obtained numerically and presented graphically. Electronic states in massive wall confinement and hard wall confinement is further obtained as limiting behavior of the states obtained in soft wall confinement. The knowledge of electronic states in such cylindrical hetrostructures semiconductor material can lead to improve the efficiency of many quantum devices.</p> R. Kumar S. N. Singh ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 473 483 10.3329/jsr.v12i4.45504 Mathematical Model and Solution for an Unsteady MHD Fourth Grade Fluid Flow over a Vertical Plate in a Porous Medium with Magnetic Field and Suction/Injection Effects <p>This work investigates the mathematical model and solution for an unsteady MHD fourth grade fluid flow over a vertical plate in a porous medium with the effects of the magnetic field and suction/injection parameters using Homotopy Perturbation Method. The flow is considered to satisfy the constitutive equations of fourth grade fluid flow model and because of the Homotopy Perturbation Method used, only the momentum equation with initial and boundary conditions are solved as governing equations. After initializing stability test, the convergence of the governing equations are observed graphically using the results of Homotopy Perturbation Method with the new analytical method used by Yurusoy in literature and there is a perfect agreement in results. The impact of dimensionless second, third and fourth grade parameters with the effects of magnetic field and suction/injection parameters on the velocity field are displayed graphically and discussed. Increase in suction parameter decreases the momentum boundary layer thickness while injection parameter enhances velocity distribution in the boundary layer. Magnetic field reduces velocity throughout the boundary layer because the Lorentz force which acts as retarding force reduces the boundary layer thickness.</p> O. J. Fenuga S. J. Aroloye S. O. Salawu ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 485 498 10.3329/jsr.v12i4.45551 Effect of Al<sub>2</sub>O<sub>3</sub> Nanoparticles and Cylindrical Pins on Natural Convection Heat Transfer in a C-Shaped Enclosure <p>A numerical study has been conducted to investigate the transport mechanism of natural convection in a C-shaped enclosure filled with water-Al<sub>2</sub>O<sub>3</sub> nanofluid for various pertinent parameters. The effects of the volume fraction of the Al<sub>2</sub>O<sub>3</sub> nanoparticles, Rayleigh number, and radius of inserted cylindrical pins on the temperature, velocity, heat flux profiles and average Nusselt number have been investigated. General correlations for the effective thermal conductivity and viscosity of nanofluids are used for this analysis. The governing mass, momentum and energy equations are solved numerically with the finite volume method using the SIMPLER algorithm. The results show that addition of nanoparticle improves the heat transfer performance. Insertion of cylindrical pins of lower radius increases the average Nusselt number irrespective of Rayleigh number. But anomaly has been observed while pins of higher radius are inserted due to enormous disturbance in the fluid.</p> M. Y. Arafat F. Faisal ##submission.copyrightStatement## 2020-08-16 2020-08-16 12 4 499 515 10.3329/jsr.v12i4.45605 Solving Some Differential Equations Arising in Electric Engineering Using Hermite Polynomials <p>In this paper, a collocation method based on Hermite polynomials is presented for the numerical solution of the electric circuit equations arising in many branches of sciences and engineering. By using collocation points and Hermite polynomials, electric circuit equations are transformed into a system of linear algebraic equations with unknown Hermite coefficients. These unknown Hermite coefficients have been computed by solving such algebraic equations. To illustrate the accuracy of the proposed method some numerical examples are presented.</p> G. Singh I. Singh ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 517 523 10.3329/jsr.v12i4.45686 Modeling the Impact of Vaccination, Screening, Treatment on the Dynamics of Pneumonia <p>In this paper we have presented a deterministic model for pneumonia transmission and we have used the model to avail the potential impact of therapy. The model is based on the vaccinated-susceptible-carrier-infected-recovered-susceptible compartmental structure and their possible interventions with the possibility of infected individual recovery from natural immunity. Here, we have modeled Pneumonia considering vaccination, screening and treatment with a system of nonlinear ordinary differential equation. The model reproduction number R<sub>0</sub> is derived and the stability of the equilibria are derived. The stability of equilibrium points is analyzed. The results shows that there exists a locally stable disease free equilibrium points, E<sub>0</sub> when R<sub>0</sub>&lt;1 and a unique endemic equilibrium E<sub>1</sub>, when R<sub>0</sub>&gt;1. Infection free point was found to be locally stable and if reproduction number is greater than unity, then there is unique endemic equilibrium point and if it is less than unity, the endemic equilibrium point is globally asymptotically stable and pneumonia will be eliminated.</p> K. S. Rahman S. R. Mitkari S. Shaikh ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 525 536 10.3329/jsr.v12i4.45815 On the Total Vertex Irregular Labeling of Proper Interval Graphs <p>A labeling of a graph is a mapping that maps some set of graph elements to a set of numbers (usually positive integers).&nbsp; For a simple graph G = (V, E) with vertex set V and edge set E, a labeling &nbsp;<span title="Greek language text" lang="el">Φ</span>: V ∪ E → {1, 2, ..., <em>k</em>} is called total <em>k</em>-labeling. The associated vertex weight of a vertex x∈ V under a total <em>k</em>-labeling &nbsp;<span title="Greek language text" lang="el">Φ</span> is defined as wt(x) =&nbsp;<span title="Greek language text" lang="el">Φ</span>(x) +&nbsp;<span class="texhtml"><a class="mw-redirect" title="Sigma (letter)" href="">∑</a></span><sub>y<span class="texhtml">∈</span>N(x)</sub> <span title="Greek language text" lang="el">Φ</span>(xy) where N(<em>x</em>) is the set of neighbors of the vertex <em>x</em>. A total <em>k</em>-labeling is defined to be a vertex irregular total labeling of a graph, if for every two different vertices x and y of G, wt(<em>x</em>)≠wt(<em>y</em>). The minimum <em>k</em> for which&nbsp; a graph <em>G</em> has a vertex irregular total <em>k</em>-labeling is called the total vertex irregularity strength of <em>G</em>, tvs(<em>G</em>). In this paper, total vertex irregularity strength of interval graphs is studied. In particular, an efficient algorithm is designed to compute <em>tvs</em> of proper interval graphs and bounds of <em>tvs</em> is presented for interval graphs.</p> A. Rana ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 537 543 10.3329/jsr.v12i4.45923 Effect of Sn Incorporation on Physical Parameters of Sb-Se Glassy System <p>The rationale of this study is to investigate band gap tailoring of Sb-Se-Sn chalcogenide glasses. This study has been accompanied by the assessment of various theoretical parameters such as average co-ordination number, Lone-pair of electrons, number of constraints, average heat of atomization, mean bond energy and glass transition temperature. It has been observed that almost all these physical parameters have been enhanced with the increase in tin (Sn) content except Lone-pair of electrons. The number of lone-pair electrons has been decreased with the increase in Sn content. The glass transition temperature has been observed to increase due to the addition of Sn atom in the Se-Sb glassy system. The band gap is decreasing with increase in Sn content due to overall decrease in the average single bond energy of the Sb-Se-Sn glassy system.</p> <p>&nbsp;</p> R. Khajuria A. Sharma P. Sharma ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 545 554 10.3329/jsr.v12i4.46048 Investigation of Magnetic and Optical Properties of Mn-Doped SnO<sub>2</sub> at Different Annealing Temperatures <p>In this paper, a systematic investigation has been done to study the effect of variation in annealing temperature on magnetic and optical properties of Mn-doped SnO<sub>2</sub>. Co-precipitation technique has been used to synthesize Sn<sub>1-x</sub>Mn<sub>x</sub>O<sub>2</sub> samples with low Mn concentration (2 %). Pristine SnO<sub>2</sub> is sintered at 350 <sup>o</sup>C. Mn-doped SnO<sub>2</sub> samples are sintered at 350, 450, 550 and 650 <sup>o</sup>C. The structures of tetragonal rutile of SnO<sub>2</sub> and Mn-doped SnO<sub>2</sub> have been confirmed by the XRD pattern. Typical ferromagnetic ordering has been observed for Mn-doped SnO<sub>2</sub> samples annealed at different temperatures. However, on increasing the annealing temperature saturation magnetization as well as the coercive field decreases, indicating a crucial phase transformation from ferromagnetism to paramagnetism. UV-Vis spectroscopy shows increase in absorbance and a slight shift in the absorption edge with Mn-doping at increasing annealing temperature indicating shifting of absorption peak towards higher wavelength. Tauc’s plot has been used to find the optical band gap (Eg).</p> S. Negi A. Sharma P. Sharma ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 555 567 10.3329/jsr.v12i4.46052 On a Slightly Different Power Law-Scaling for the Flat Universe <p>A slightly different power law-scaling fits to the picture of our 13.7 billion years old flat universe which is expanding presently at 67 km/s/Mpc with an acceleration. The model which is an attempt to retain power-law scaling in the light of the accepted facts about the universe we are living in, has a constant effective equation of state parameter as the cosmic fluid is a solution of matter, radiation and dark energy. It is successful in explaining the acceleration of universe which the normal power law fails if the present Hubble parameter is 67 km/s/Mpc and age of the universe is 13.7 billion years, and it is free from the defect of singularity.</p> C. Sivakumar R. Francis ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 569 574 10.3329/jsr.v12i4.46721 Design of Hybrid Blind Detection Based Spectrum Sensing Technique <p>Cognitive Radio is a boon to efficient utilization of spectrum to meet the demand of next generation. Spectrum Sensing (SS) is an active research area, essential to meet the requirement of efficient spectrum utilization as it detects the vacant bands. This paper develops a Hybrid Blind Detection (HBD) technique for cooperative spectrum sensing which combines the Energy Detector (ED) and the Anti-Eigen Value Detection (AVD) techniques together to enhance the detection accuracy of a cognitive radio. Collaboration among the cognitive users is achieved to reduce the error and hard fusion based detection is implemented to detect the existence of primary user. The detection accuracy of the design is evaluated with respect to detection probabilities and the results are examined for improvements with the traditional two stage detection techniques. Fusion rules for the cooperative environment are implemented and compared to detect majority rule suitable for the proposed design.</p> V. Sharma S. Joshi ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 575 583 10.3329/jsr.v12i4.46870 Sumudu Decomposition Method for Solving Fractional Bratu-Type Differential Equations <p>The purpose of this paper is to introduce Sumudu decomposition method for solving Fractional Bratu-type differential equation. This method is a combination of the Sumudu transform and Adomian decomposition method. The fractional derivative is described in the Caputo sense. The Sumudu decomposition method is applied to obtain approximate analytical solution of non-linear Fractional Bratu-type differential equation. A novel combination of Sumudu transform and Adomian decomposition provides approximate solution in the form of infinite convergent series solution. The behavior of approximate analytical solutions and exact solutions for different values of <span title="Greek language text" lang="el">α</span> are plotted graphically. The results acquired from Sumudu decomposition method indicates that the proposed method is very well founded, suitable and effective. Finally, some numerical examples are given to illustrate the efficiency and applicability of our method.</p> N. B. Manjare H. T. Dinde ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 585 605 10.3329/jsr.v12i4.47163 Studies on Structure and Elasto-Mechanical Properties of Suvin Cotton Fibre <p>The comprehensive elastic properties of Suvin cotton fibre have been estimated. The Linked Atom Least Square method (LALS) technique has been employed to compute the structural properties using the X-ray diffraction data. Using Treloar’s assumptions the elastic stiffness matrix |Cij| has been calculated, then by utilizing the Voigt theory the elastic constants like Young’s modulus (E), Bulk modulus (K), Shear modulus (G), Poisson’s ratio (<span title="Greek language text" lang="el">ν</span>) and linear compressibility (<span title="Greek language text" lang="el">β</span>) have been estimated. Further, the experimental results of elastic constants are obtained and compared with the computed results and a broad correlation between them has been observed. ELATE web application tool is used to obtain the 3-dimensional images of variation of elastic constants along their spatial axes. From these figures an attempt has been made to explain the anisotropic mechanical property with respect to directional dependent Young’s modulus (E) and Shear modulus properties (G).</p> V. V. Manju S. Divakara R. Somashekar ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 607 620 10.3329/jsr.v12i4.47269 Analysis of Proximate Composition and Functional Properties of Selected Edible Leaves: Nutritional and Therapeutic Implication <p>The present study was designed to document the nutritional and functional properties of Ceylon Spinach, Mustard as well as Pumpkin leaves. These samples were selected owing to their economic affordability and utilization within the local population. Proximate analysis revealed a significant percentage of minerals, proteins, carbohydrates and vitamin C in all the leaf extracts. Phytochemical screening displayed Ceylon Spinach, Pumpkin and Mustard leaves to be rich sources of polyphenols (106.6, 76.24 and 89.86 mg/100 g) and alkaloids (12.8 %, 13.2 % and 16.8 %) respectively. Furthermore, these edible leaves could effectively scavenge 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) and hydrogen peroxide (H2O2) free radicals with Mustard leaves showing the greatest efficiency, hence portraying antioxidant properties. Ceylon Spinach leaves depicted the highest reducing power compared to the other samples. Additionally, the edible leaf extracts were shown to possess anti-bacterial abilities with Mustard leaves displaying the strongest inhibition against growth of both Gram positive (ZOI 18.5mm) and negative bacteria (ZOI 25.5mm). Interestingly, the selected samples could also elevate the growth of probiotic Lactobacillus acidophilus in vitro thereby confirming their prebiotic potential. Therefore, inclusion of these edible leaves in the diet may promote good health owing to their nutritional and therapeutic benefits.</p> A. D. Pal T. M. Zakir ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 621 632 10.3329/jsr.v12i4.45110 Groundwater Conditions and Hydrogeochemistry of the Sombreiro-Warri Deltaic Plain Deposit (Shallow Benin Formation) in the Vicinity of Agbarho, Nigeria <p>Groundwater conditions and hydrogeochemistry in the Sombreiro-Warri Deltaic Plain deposit at the Agbarho area were described with the aid of data obtained from dug wells. Ten dug wells and two surface water locations were sampled for water quality analysis. Regional groundwater flow is from the northeast to southwest direction with local distortion resulting from sustained groundwater withdrawal in more populated areas of the town. pH in surface water range was from 4.9 to 5.4 and that of groundwater from 3.8 to 5.9. TDS in groundwater and surface water ranges were from 39.6 to 123 mg/L and 9 to 25.6 mg/L, respectively. Two hydrochemical facies, magnesium chloride and sodium chloride facies were defined in this study. The order of abundance of cations are Mg&gt;Na+K&gt;Ca, Na+K&gt;Mg&gt;Ca and Na+K&gt;Ca&gt;Mg and for anions is Cl&gt;HCO<sub>3</sub>&gt;SO<sub>4</sub>. This study indicates that the groundwater chemistry is controlled largely by precipitation. Water qualities from the dug wells and surface water are well within the SON permitted levels except faecal coliform occurring at minimal level in two wells and one of the locations on the river.</p> O. Efobo F. C. Ugbe I. A. Akpoborie ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 633 643 10.3329/jsr.v12i4.45187 Topological Indices of Dendrimers used in Drug Delivery <p>The topological index is a numerical representation of a molecular structure. In chemical graphs, the atoms and the chemical bonds between them are represented by vertices and edges respectively. Vertex degree based topological indices are the most studied and mostly used type of topological indices. The mostly used vertex degree based topological indices in the field of drug design and developments are the Zagreb index and the Randić index. The structural chemistry of dendrimers could be manipulated by their topological indices to get the specific structure with required properties to deliver the drugs to target carrier vehicle. In this work, topological indices of three types of dendrimers which are used as the drug delivery system were studied and their Zagreb index and the Randić index were calculated using molecular graph theory. Moreover, the other versions of these two indices were also calculated to these dendrimers.</p> T. P. Jude E. Panchadcharam K. Masilamani ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 645 655 10.3329/jsr.v12i4.45389 Changes in Phytochemicals and Determination of Optimum Fermentation Time during Black Tea Manufacturing <p>Black tea processing consists of four steps, namely withering, CTC, fermentation and drying, while cup quality made tea mostly controlled by fermentation step. This study evaluated biochemical changes at different stages of black tea processing in Bangladesh and determined the optimum fermentation time. Samples were collected from different tea processing stages to measure major phytochemicals and time intervals during fermentation to measure theaflavins and thearubigins ratio. Caffeine content was the least susceptible to processing steps. Biochemical changes started at withering, cell maceration and enzymatic oxidation started at CTC processing, thus the major reduction in the reducing sugar (20.46 to 04.95 ppm), catechin (16.88 to 7.95 ppm) and polyphenol (42.30 to 30.73 ppm) occurred here. The significant changes appeared during fermentation when polyphenol content decreased from 44.66 to 18.23 and catechin from 17.41 to 03.98 ppm due to the breakdown of these compounds to theaflavins (TF) and thearubigins (TR). The TF and TR ratio increased with fermentation time, and the highest of 1:8.4 was found at 50 min, which turned into 1:10 in the final product. The made tea quality parameters were comparable or better at fermentation time of 50 min than the quality of the black tea available in market.</p> M. M. Rahman M. M. Hossain R. Das I. Ahmad ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 657 664 10.3329/jsr.v12i4.45452 Mumunine - A New Carbazole Alkaloid from <i>Murraya koenigii</i> (Linn.) Spreng <p>The plant <em>Murraya koenigii</em>, commonly known as curry leaf tree is a rich source of carbazole alkaloids. A number of monomeric as well as dimeric carbazoles with C<sub>13</sub>, C<sub>18</sub> and C<sub>23</sub> skeleton have been isolated from the plant. In my present work, a new carbazole alkaloid, designated as mumunine, was isolated from the bark of <em>Murraya koenigii</em> (Linn) Spreng, along with a known carbazole alkaloid, viz. mahanimbine. The structure of the new alkaloid <strong>1</strong> was elucidated on the basis of 1D and 2D NMR spectral data analysis. In this paper, the isolation and structure elucidation of the new compound will be discussed in detail.</p> M. Chakraborty ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 665 672 10.3329/jsr.v12i4.45499 Microwave Assisted Efficient Synthesis of Some Flavones for Antimicrobial and ADMET Studies <p>Microwave (MW) assisted synthetic technique was applied for the preparation of chalcone derivatives 5-7 employing Claisen-Schmidt condensation between 2-hydroxyacetophenone and aromatic aldehydes. These chalcones were further subjected to oxidative cyclization via MW irradiation and furnished the related flavones <strong>8-10</strong> which were characterized by FT-IR, <sup>1</sup>H and <sup>13</sup>CNMR spectra. The use of these MW assisted reactions provided higher productivity (92-98%) in shorter reaction time (2-6 min) with eco-friendly mild reaction conditions and hence found to be a convenient method as compared to conventional synthesis. These chalcones <strong>5-7</strong>, and flavones <strong>8-10</strong> were screened for in vitro antimicrobial activities against five bacterial and three fungal pathogens. The study indicated that they were more active against fungal pathogens than that of bacterial organisms and comparable to the standard antifungal antibiotic nystatin. Interestingly, the prediction of activity spectra for substances (PASS) was also found in agreement with the in vitro results. Some of the compounds were found to have good ADMET properties.</p> M. A. Rahim M. M. H. Bhuiayan M. M. Matin ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 673 685 10.3329/jsr.v12i4.45523 Polythiophene Coated Cellulosic Fibers from Banana Stem for Improved Electrical, Mechanical, Thermal and Dielectric Properties of Polypropylene Composites <p>Incorporating conducting polymer coated fibers in a nonconducting base polymer has proven to be an effective method for the preparation of conducting composites. In the present work, banana fibers, cellulosic microfibers from waste biomass, were used for the coating of conducting polymer through in situ polymerization of thiophene on the fiber surface. The polythiophene (PTH) coated fibers were used as the conducting elements in a general-purpose thermoplastic, polypropylene (PP). The prepared composites were examined for electrical, thermal, mechanical, dynamic mechanical and dielectric properties. Formation of a continuous conducting network of PTH coated fibers in the polymer matrix imparted 6 fold increase in conductivity, 22 % improvement in tensile strength and 47% improvement in tensile modulus. Thermal degradation temperature of polypropylene was improved up to 26 <sup>o</sup>C. An exceptional improvement of more than 3 orders of magnitude in dielectric constant could be achieved for the composites making them suitable for capacitor applications.</p> J. Thekkedath P. K. Bipinbal T. Thomas S. K. Narayanankutty ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 687 699 10.3329/jsr.v12i4.45774 Characterization of Inhalable Ground-Level Ambient Particulate Matter in Dhaka City, Bangladesh <p>The capital Dhaka of Bangladesh is one of the most densely populated and air polluted cities in the world. This study is aimed to assess the trend of Particulate Matter (PM<sub>2.5</sub> and PM<sub>10</sub>) from 2013 to 2018 in relation to meteorological parameters. PM data were collected from the Continuous Air Monitoring Station (CAMS) at Darus Salam point in Dhaka city. CAMS gather air samples through beta gauge instrument which measures the volume of gas extracted through the stack/duct and calculates mass concentration. In the present study, PM<sub>2.5</sub> was 54 % of that of PM<sub>10</sub> which is fine particulate matter. PM<sub>2.5</sub> and PM10 had the lowest concentration in the month of July due to the highest rainfall rate whereas it was highest in the months of January and December. In addition, annual average concentration of PM<sub>2.5</sub> and PM<sub>10</sub> is observed to be 5-6 times higher than Bangladesh National Ambient Air Quality Standard (BNAAQS) while higher PM concentrations were observed in winter seasons. This study found significantly inverse association between ground-level PM and meteorological parameters in Dhaka city. Air pollution is deteriorating rapidly in Dhaka city and it is high time to implement the Clean Air Act urgently to reduce such destruction.</p> A. A. Nayeem M. S. Hossain A. K. Majumder ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 701 712 10.3329/jsr.v12i4.45802 Ecomorphological Traits Determine Assemblage Pattern of Small Freshwater Fish in Smaller Lentic Aquatic Bodies <p>The present study investigated ecomorphological patterns of fish assemblage from freshwater ponds on two functional categories, i.e., foraging behavior and habitat preference. Nine ecomorphological indices were derived from eight morphometric variables and examined on 566 adult individuals belonging to 9 species, 7 families and 4 orders. Samples were collected during April 2016 to September 2017 from freshwater ponds in Birbhum, West Bengal. Mantel test was performed to investigate correlation between morphological, taxonomic, trophic and habitat guild matrices. The partial Mantel test was done to investigate the direct correlation between trophic and habitat guilds with morphology discounting the effect of taxonomic relatedness on species assemblage. The interspecific ecomorphological diversification pattern was analysed by HCPC method. At least three ecomorphological assemblages among these fish species with two significant principal axes of variations were observed. Ecomorphological attributes associated with mouth aspect ratio, compression index and relative body height were on PC1 axis, and relative length and height of head, relative area of eye were on PC 2 axis. Mantel and partial Mantel test showed significant correlation between morphology and trophic guild structure. Outcomes show that morphology is a good predictor of trophic structure of fish assemblage in studying convergent assemblage pattern irrespective of taxonomy.</p> S. Roy S. I. Maiti S. K. Saikia S. Ray ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 713 727 10.3329/jsr.v12i4.45998 pH and Temperature Dependent Gut Enzyme Niche in a Stomachless Herbivorous Freshwater Fish <i>Amblypharyngodon mola</i> (Hamilton, 1822) <p>The activities of digestive α-amylase (E. C., total proteases, and bile salt-activated lipase (E. C. 3.1.1.-) along the digestive tract (lengthwise divided into five equal parts) of a stomachless freshwater fish (n = 10, weight = 4.354±0.316 g, standard length = 21.641±2.271 cm) were measured at different pH and temperature levels. Different optimum pH and temperature for the activity of α-amylase (8-9, 35°C), proteases (7-8, 45°C), and lipase (8, 45°C) were observed. The first two regions of the digestive tract showed comparatively higher activity of all enzymes. The hierarchical clustering technique revealed three different enzymatically active regions, more inclined to pH in the digestive tract of the studied fish. The present study also supports that the stomachless gut of A. mola has substantial resemblances to the intestinal part of the digestive tract of fish.</p> S. Debnath S. I. Maiti S. K. Saikia ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 729 741 10.3329/jsr.v12i4.46003 Biochemical, Microbiological and Organoleptic Properties of Probiotic Pineapple Juice Developed by Lactic Acid Bacteria <p>An experiment was undertaken to determine the suitability of pineapple juices as raw materials for the production of fermented probiotic juice by two lactic acid bacteria, <em>Lactobacillus plantarum</em> and <em>Lactobacillus fermentum</em>. Three probiotic juice samples inoculated with <em>L. plantarum </em>(S-2), <em>L. fermentum</em> (S-3) and with both <em>L</em>. <em>plantarum</em> and <em>L</em>. <em>fermentum</em> (S-4) were compared with that of control sample (S-1) where no <em>Lactobacillus</em> strains were used. Fermentation was carried out at 37 °C for 48 h. Then the juice samples were stored at 4 °C and studied the change in their physicochemical properties at day 0, 7, 14 and 21. Both <em>L. plantarum</em> and <em>L. fermentum</em> were able to withstand and utilize fruit juices for their cell synthesis as indicated by a decrease in fruit sugar and an increase in acidity. Although the lactic cultures in fermented probiotic juices gradually lost their viability, the viable cell counts of these strains remained at 10<sup>7 </sup>CFU/100 mL after 14 days in cold storage. From sensory evaluation, the juice sample prepared with <em>L</em>. <em>plantarum</em> exhibits the best result during storage time. Hence, pineapple juice might be used as a suitable medium for the production of a healthy probiotic beverage.</p> M. A. Hossain M. M. Hoque M. M. Hossain M. H. Kabir M. Yasin M. A. Islam ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 743 750 10.3329/jsr.v12i4.46179 Solid State Fermentation of Maize (<i>Zea mays</i>) Offal by <i>Rhizopus</i> <i>oligosporus</i> under Acidic and Basic Conditions <p>Maize offal, a by-product of maize milling industry that constitutes environmental pollution is under-utilized. This study investigated the effect of solid state fermentation on maize offal using <em>Rhizopus oligosporus</em> under acidic and basic conditions (pH range of 3 to 9). Soluble proteins content, glucose and amylase activity of the fermented by-products were evaluated after five days’ period of fermentation. The result showed a significant increase in soluble proteins content at pH 3, glucose at pH 6 and amylase activity at pH 7 when compared with the control (P &lt; 0.05). This showed that solid state fermentation improves the nutritional value of maize offal at different pH values. Thus, livestock feeds formulation industries could harness this process in the utilization of maize offal for poultry, other farm animal feeds and food fortification for protein enhancement thereby, preventing environmental pollution.</p> A. A. Anigboro E. Aganbi N. J. Tonukari ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 751 756 10.3329/jsr.v12i4.46993 Interaction between Biological Nitrogen Removal Processes and Operating Parameters: A Review <p>Nitrogen, mostly in the form of ammonia or nitrate containing wastewater deteriorated the water quality which simultaneously affects environment, plants, animals and human life. A number of researchers nowadays are conducting research to find out efficient and cost effective nitrogen removal technique along with optimum operating parameters. It is very important to uncover the optimum range of each parameter. In this study, it was winnowed to elicit the optimum operating ranges of dissolved oxygen concentration, temperature, pH, free ammonia concentration, nitrate concentration and culture medium. The nitrogen removal techniques were compared, evaluated considering advantages and disadvantages of them. Partial nitrification combined with anaerobic ammonium oxidation was found most prospective nitrogen removal technique for wastewater treatment compare to other techniques (conventional nitrification-denitrification over nitrate/nitrite, anammox, SND etc.) due to less oxygen consumption (62.5 % less), less sludge production, no carbon requirement, single reactor used and energy efficiency. SND process was more economical due to faster consumption of ammonia, nitrite and nitrate. There was various culture mediums which had a favorable or detrimental effect on specific nitrogen removal processes. However for desired bacteria culture for specific application, suitable culture medium needs to be selected considering the optimal operating parameters for microbial growth.</p> M. S. I. Mozumder M. D. Hossain ##submission.copyrightStatement## 2020-09-01 2020-09-01 12 4 757 774 10.3329/jsr.v12i4.46092