Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS Official journal of the Faculty of Science, Dhaka University. Full text articles available. en-US deansc@univdhaka.edu (Professor Dr. Maqbulur Rahman) banglajol.info@gmail.com (Md Fahmid Uddin Khondoker) Sun, 24 Jul 2022 11:02:11 +0000 OJS http://blogs.law.harvard.edu/tech/rss 60 Optical and Structural Study of the CZTS (Cu2ZnSnS4) Thin Film for Solar Cell Derived from the Chloride-Based sol-gel Precursor Solution https://www.banglajol.info/index.php/DUJS/article/view/60374 <p>Fabrication of environmentally safe C2ZnSnS4 (CZTS) photovoltaic thin films of pure kesterite state is crucial. We have prepared<br>CZTS thin films by sol-gel dip-coating process from chloride-based chemicals. After vacuum-annealed at 550°C, the optical and<br>structural characters of the films were further examined by UV–vis spectroscopy, X-ray diffraction (XRD), scanning electron<br>microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) methods. The CZTS films offered high optical absorption<br>(0.4x104cm-1) and nearly optimum bandgap energy (1.65e V). X-ray diffraction examination confirmed the kesterite structure of<br>films. Scanning electron micrograph affirmed the creation of jam-packed, condensed and granulated CZTS films. The thin film<br>displayed intermittent disposal of agglomerated particles with clear-cut edges. The energy dispersive X-ray spectroscopy study gave<br>the stoichiometric ratio as Cu: Zn: Sn: S= 2.2: 1.4: 1: 5.1.</p> <p>Dhaka Univ. J. Sci. 70(1): 1-7, 2022 (January)</p> M Rahman, MS Bashar, N Islam Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60374 Sun, 24 Jul 2022 00:00:00 +0000 An Econometric Analysis to Forecast the Food Grain Production in Bangladesh by Using ARIMA and VAR Models https://www.banglajol.info/index.php/DUJS/article/view/60375 <p>In this study, an Econometric analysis has been conducted to identify the important factors that affect the food grain productions in<br>Bangladesh. Here, we have considered time series data for the years from 1989- 1990 to 2019-2020. Vector Autoregressive (VAR)<br>Model and Autoregressive Integrated Moving Average (ARIMA) model have been considered in this study. Both these models<br>have been considered to forecast the productions of food grains in Bangladesh. The forecasting performances of these two models<br>have been compared by using RMSE, MAE, and MAPE. It has been found that the VAR model is better than the ARIMA model to<br>forecast the food grain production. On the other hand, it has been come out from the analysis that there is no significant impact of<br>chemical fertilizer on the food grain production, but irrigation area has significant impact on the food grain production. Among the<br>three variables: food grain production, irrigation area and chemical fertilizer, there exists short run relationship.</p> <p>Dhaka Univ. J. Sci. 70(1): 8-13, 2022 (January)</p> Md Mehedi Hossain, Murshida Khanam, Salma Akhter Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60375 Sun, 24 Jul 2022 00:00:00 +0000 The State of Healthcare Facilities to Provide Diabetes, Cardiovascular and Chronic Respiratory Disease Related Services in Bangladesh https://www.banglajol.info/index.php/DUJS/article/view/60376 <p>The rapid rise of diabetes, cardiovascular disease (CVD) and chronic respiratory disease (CRD) are causing serious challenges for<br>Bangladesh to achieve the sustainable development goal (SDG) target 3.4 by 2030. The study aims to describe the state of healthcare<br>facilities to provide diagnosis and treatment for diabetes, CVD and CRD related services in Bangladesh. This cross-sectional study<br>used data from 2017 Bangladesh Health Facility Survey (BHFS). A total of 406 health facilities providing all three services were<br>considered for this study. Findings of the study illustrated that there were rural-urban disparities in healthcare facilities to provide<br>diabetics, CVD, CRD related services. Diabetics and CRD related services were significantly higher in public healthcare facilities<br>of urban areas compared to rural areas (P &lt;0.008 and P&lt;0.001, respectively). Also, public health facilities of urban areas were more<br>likely to provide CVD related services compared to rural areas. While private healthcare facilities of urban areas were more likely<br>to provide CVD, CRD related services than rural areas. Private healthcare facilities of rural areas were in better condition to provide<br>diabetes related services than urban areas. However, the country is yet to attain optimal progress in the overall status of health sector.<br>Therefore, in order to cope up with the rising burden of diabetes, CVD and CRD and to minimize the burden of disease specific outof<br>pocket healthcare expenses, recommendations include strengthening and improving stewardship, improving quality of services<br>and improving monitoring as well as supervision of decentralized healthcare facilities.</p> <p>Dhaka Univ. J. Sci. 70(1): 14-21, 2022 (January)</p> Gaylan Peyari Tarannum Dana, Sawkia Afroz Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60376 Sun, 24 Jul 2022 00:00:00 +0000 Determination of Toxic Heavy Metal Contents of Some Selected Tropical Fruits Grown in Industrial Areas of Bangladesh https://www.banglajol.info/index.php/DUJS/article/view/60377 <p>Fourteen tropical fruit items were collected from different industrial sites of the Dhaka and Chattogram region, Bangladesh to<br>determine toxic heavy metal contents. This study aimed at the assessment of the distribution of heavy metals (As, Pb and Cr) as well<br>as comparison of their level among different locations. The fruit items were analyzed for the quantification of the selected heavy<br>metals using Atomic Absorption Spectrophotometer (AAS). The range of lead, chromium and arsenic in the fruit items were 1.12<br>± 0.077 to 2.899 ± 0.013, 0 to 0.217 ± 0.005 and 0 to 0.078 ± 0.002 mg kg-1 respectively. It was revealed from the results that the<br>level of toxic metals (As, Cr) in almost all fruit samples were within tolerable limit whereas the level of Pd in all of the fruit samples<br>exceeded the acceptable limits of WHO standard value. It was also observed from the results obtained that the concentration of the<br>metals found in the samples from Dhaka regions were considerably higher than that of Chattogram. These metal contributors mainly<br>arising from anthropogenic sources including industrial wastes, automobile emissions, use of fertilizers, pesticides and herbicides in<br>agriculture, paints, sewage and waste disposal. The extended level of these metals causing environmental pollution is hazardous since<br>plants accumulate them. Subsequently, crops uptaking these heavy metals consumed by humans and animals which is detrimental to<br>health. It is therefore very important that necessary actions need to be taken to monitor the level of these deleterious elements in food<br>plants. In decision making, planning and risk assessing this present study will play significant role.</p> <p>Dhaka Univ. J. Sci. 70(1): 22-27, 2022 (January)</p> Md Ashraful Islam, Maksuda Parvin, Md Fahad Bin Quader, Md Shakhawat Hossain Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60377 Sun, 24 Jul 2022 00:00:00 +0000 Mixed Ligand Binuclear Complexes of Copper(II) and Cadmium(II) with Adenine and 1,4-Diazabicyclo[2.2.2]octane https://www.banglajol.info/index.php/DUJS/article/view/60378 <p>Mixed ligand binuclear complexes of Cu(II) and Cd(II) with adenine (Ade) and 1,4-diazabicyclo[2.2.2]octane (DABCO) have<br>been synthesized at a metal to ligands (M:L:L′) molar ratio of 1:1:1 in aqueous medium under ambient conditions. All synthesized<br>complexes are powdery solids of different colours, slightly soluble in hot water and decompose at high temperature. Characterization<br>of the complexes was accomplished using various analytical techniques, e.g. metal and chloride content analysis, Fourier transform<br>spectrophotometer (FT-IR), UV-visible spectrophotometer, magnetic measurement, and thermal analyses. The metal and chloride<br>contents analyses of the complexes reveal to their stoichiometry [M2Cl2(Ade)2(H2O)2(DABCO)]Cl2 [M = Cu(II) or Cd(II)]. Analytical<br>data suggests that they are homo metal symmetric binuclear complexes comprises of two [MCl(Ade)(H2O)] moieties in between<br>a DABCO molecule is N,N′-bridge bonded. The arrangements of the ligands around the metal centers are essentially tetrahedral<br>involving N(9) of deprotonated imidazole moiety, one Cl- ion, one oxygen from the water molecule and one tertiary N atom from<br>DABCO completing the coordination. Proton migration occurs from N(9) to the N(1) site resulting into a zwitterionic form of<br>adenine, additionally N(3) site of which is hydrogen bonded with the coordinated water molecule. Electrochemical redox behaviour<br>of Cu(II) in presence of adenine and DABCO in the aqueous medium was also studied. It exhibits quasi-reversible one-electron<br>transfer processes.</p> <p>Dhaka Univ. J. Sci. 70(1): 28-33, 2022 (January)</p> Sumaia Abdullah, MS Rahman, AA Shaikh, Pradip K Bakshi Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60378 Sun, 24 Jul 2022 00:00:00 +0000 Simulation Based Temperature Profiling of Human Eye due to the Exposure of LED Light https://www.banglajol.info/index.php/DUJS/article/view/60379 <p>The use of LED luminaries is increasing day by day and the traditional sources of light are being replaced by this semiconductor<br>technology. In this study, the interactions of Red, Green and Blue LED light with human-eye are considered to model the temperature<br>profile due to the attenuation in the ocular media. The simulation has been done using COMSOL Multiphysics 5.3. The results of the<br>study show that Blue LED light causes temperature rise more than the other two colours of light. At the tip of the corneal surface,<br>blue LED light causes the temperature to rise by 0.91⁰C whereas the rise of temperature for green and red LED are 0.85⁰C and<br>0.46⁰C respectively. However, the temperature at the posterior layers of the eye, sclera, choroid and retina undergoes little thermal<br>effects due to LED light owing to the fact that the heat-flux due blood flow is dominant in that region.</p> <p>Dhaka Univ. J. Sci. 70(1): 34-41, 2022 (January)</p> Md Ashiqur Rahman, Mamun Rabbani Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60379 Sun, 24 Jul 2022 00:00:00 +0000 Composition of Energy Drink Samples in Bangladesh https://www.banglajol.info/index.php/DUJS/article/view/60380 <p>The commercial energy drink samples of 10 different brands were analyzed to study the level of alcohol (if any), sodium benzoate,<br />caffeine, vitamin B, and carbohydrates content. Samples were degassed by ultrasonicator, and CO2 was found to be in a range of 1.27<br />± 0.05 to 4.10 ± 0.10 mL per 100 mL sample. The amount of caffeine, sodium benzoate, glucose, and vitamin B were studied by a<br />UV-Visible spectrophotometer. The wavelength of absorption maxima was 224, 272, 489, 445, and 292 nm, respectively, for sodium<br />benzoate, caffeine, glucose, vitamin B2, and vitamin B6. The correlation coefficients of the calibration curves were found to be<br />0.998, 0.992, 0.998, 0.997, and 0.989 for caffeine, glucose, sodium benzoate, vitamin B2 and vitamin B6, respectively. The alcohol<br />content was studied by gas chromatography equipped with a flame ionization detector. Ethanol was not found to be present in any<br />sample. The caffeine and sodium benzoate content in different samples was found in the range of 147.84 ± 0.53 to 846.78 ± 2.64 and<br />52.92 ± 6.23 to 1575.37 ± 4.99 μg/mL, respectively. The sugar content in different samples was found to be 16.16 ± 4.25 to 338.33<br />± 0.75 mg/mL. Vitamin B2 was found to be 13.21± 0.08 and 1.04 ± 0.002 μg/mL, respectively in Bacchus and Wild Brew samples<br />and Vitamin B6 was found to be 261.17 ± 8.38 and 115.88 ± 0.31 μg/mL in Red Bull and Bacchus samples, respectively. The pH of<br />the samples was found to be in the range of 2.79 ± 0.04 to 4.88 ± 0.04.</p> <p>Dhaka Univ. J. Sci. 70(1): 42-48, 2022 (January)</p> Md Reazul Alam Refat, Polash Nandi, Mohammad Shoeb, Abida Sultana Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60380 Sun, 24 Jul 2022 00:00:00 +0000 Assessment of Physico-Chemical Parameters of Water Samples Collected from the Southern Part of Bangladesh https://www.banglajol.info/index.php/DUJS/article/view/60381 <p>Bangladesh has a vast natural water resources. In order to determine the water quality parameters such as pH, EC, DO, BOD, TOC, ions<br />i.e., NO3-, SO42-, PO43- and heavy metals, thirty surface water samples were collected from the southern part of Bangladesh including<br />the coastal regions of Patuakhali district and Kuakata sea beach area during the dry season. The pH of water samples was ranged from<br />7.58 to 8.77 with an average of 8.15. The average conductivity value was 8.83±2 mS/cm. The average DO was 8.33±1.82 mg/L and<br />BOD was 0.31±0.03 mg/L. TOC was found between 0.78 and 1.78 mg/L with an average of 1.24 mg/L. The concentration of NO3<br />-,SO42-, PO43- was determined by ion chromatography and only sulphate ion was detected in a very low concentration. Water samples<br />from different sources were analysed for five metals by AAS and the concentrations of Pb, Cd, Mn, Hg and As were below 0.2, 0.01,<br />0.22, 0.001 and 0.005 mg/L, respectively.</p> <p>Dhaka Univ. J. Sci. 70(1): 49-57, 2022 (January)</p> Mohammad Shoeb, Farhana Sharmin, Md Nazrul Islam, Lutfun Nahar, Rafiza Islam, Nargis Parvin Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60381 Sun, 24 Jul 2022 00:00:00 +0000 Proximate Analysis of Melon Seeds Available in Bangladesh https://www.banglajol.info/index.php/DUJS/article/view/60382 <p>The seeds of winter (wax gourd), long (bottle gourd) and large (pumpkin) melon were analyzed for nutritional parameters mainly<br />protein, fat/oil, carbohydrate, dietary fiber, protein, minerals and moisture and fatty acids composition. The double beam ultravioletvisible spectrophotometer was used for analysis of total sugar. The protein content was determined using the Kjeldahl method. An atomic absorption spectrophotometer was used to quantify minerals (Fe, Cu, and Zn). Fatty acid was analyzed by gas chromatography<br />(GC) equipped with a flame ionization detector (FID). From the proximate analysis, it was found that the winter melon (wax gourd)<br />seeds contain protein, oil, carbohydrate, soluble dietary fiber, moisture and ash content of 19.71, 16.46, 56.48, 3.10, 68.88 and 4.26<br />%, respectively. Similarly, long melon (bottle gourd) was found to contain 16.12, 13.61, 46.88, 2.2, 76.45 and 5.2% of protein, oil,<br />carbohydrate, soluble dietary fiber, moisture and ash, respectively. The contents of protein, oil, carbohydrate, soluble dietary fiber,<br />moisture and ash in large melon (pumpkin) seeds were found to be 29.64, 18.17, 55.32, 1.3, 79.53 and 5.12%, respectively. In mineral<br />analysis, iron, copper, and zinc contents were found to be 6.75, 0.62, and 6.10 mg/100g in winter melon; 7.8, 1.63, and 4.25 mg/100g<br />in long melon; and 13.95, 1.15, and 5.11 mg/100g in large melon, respectively.</p> <p>Dhaka Univ. J. Sci. 70(1): 58-63, 2022 (January)</p> Md Reazul Alam Refat, Mohammad Shoeb, Abida Sultana Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60382 Sun, 24 Jul 2022 00:00:00 +0000 Cu(II) Doped TiO2 for Photodegradation of Remazol Black B in Aqueous Solution https://www.banglajol.info/index.php/DUJS/article/view/60383 <p>In the present investigation, Cu(II) doped TiO<sub>2</sub> was prepared by a precipitation method. The precipitate was calcined at 300 ºC for<br />2 hours. The prepared doped catalyst was characterized by scanning electron microscope (SEM), energy dispersive X-ray (EDX)<br />spectroscopy and X-ray diffractometry (XRD). SEM images revealed that the morphology of the doped catalyst was different from<br />that of TiO<sub>2</sub>. Elemental analysis was accomplished by EDX that indicated the presence of Cu, Ti and O atoms in the prepared sample.<br />XRD analysis confirmed that TiO<sub>2</sub> was present as anatase with almost no distortion in peak position due to the presence of Cu(II)<br />in some interstitial sites. Photodegradation of remazol black B (RBB) was carried out at different experimental conditions under<br />different light sources. The catalytic efficiency of Cu(II) doped TiO<sub>2</sub> increased up to a certain dosage then reduced with a further<br />increase in the amount of photocatalyst. The optimum conditions for degradation was found at pH 3.0 under UV light. Under these<br />experimental conditions, Cu(II) doped TiO<sub>2 </sub>degraded 98.8% of RBB, on the other hand, undoped TiO<sub>2</sub> degraded only 80.0% of RBB.</p> <p>Dhaka Univ. J. Sci. 70(1): 64-69, 2022 (January)</p> Md Abdul Momen, Md Ataur Rahman, Hosne Ara Begum, Md Mufazzal Hossain Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60383 Sun, 24 Jul 2022 00:00:00 +0000 Sensitivity of Different Physics Schemes in the Simulation of Heat Wave Events over Bangladesh Using WRF-ARW Model https://www.banglajol.info/index.php/DUJS/article/view/60384 <p>Heat waves (HWs) are an extreme temperature condition that has a direct impact on human lives. In recent years, a large number of<br>people have died all over the world due to hot weather. The purpose of this study is to predict HWs accurately to mitigate the casualties<br>caused by them. Two HW events are selected for this study (Event-1: 0000 UTC of 18 May to 0000 UTC of 25 May 2015, Event-2:<br>0000 UTC of 05 April to 2100 UTC of 08 April 2015). At first, sensitivity tests have been done using different combinations of<br>physics schemes. Sensitivity of Planetary boundary layer (PBL) and surface layer (SL) schemes combinations (YSU-Revised MM5,<br>YSU-MM5, MYJ-Eta, and ACM2-Revised MM5) and land surface models (RUC, Noah, Noah-MP, and CLM4) are investigated to<br>predict Comfort Index (CI), which is identified by using Physiological Equivalent Temperature (PET). To simulate PET, the primary<br>meteorological variables 2-m air temperature (T2), 2-m relative humidity (rh2), mean radiant temperature (TMRT), wind speed at 10<br>m (ws10), and cloud cover data have been used. These parameters were simulated by the WRF model using both single and nested<br>domains. The experiments found that the combination of the YSU-MM5 scheme and the Noah land surface model predicted the<br>WRF simulated variables very well. The study also found that the CI exists between the slight heat stress to extreme heat stress and<br>the maximum PET values were found to be 47.6 ºC and 48.5 ºC for Rajshahi and Khulna event respectively.</p> <p>Dhaka Univ. J. Sci. 70(1): 70-78, 2022 (January)</p> Sahadat Jaman, Md Jafrul Islam, Ashik Imran, Md Kamruzzaman, MAK Mallik, Pappu Paul, IM Syed Copyright (c) 2022 Dhaka University Journal of Science https://www.banglajol.info/index.php/DUJS/article/view/60384 Sun, 24 Jul 2022 00:00:00 +0000