Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60022
M. B. Hasan, Lipi Akhter
Business organizations are always facing uncertainties in demand, supply and inventories. For this, it is important for them to make the strategic plans to cope up with the uncertainty accordingly. To sustain, the business organizations must plan the future in such a way that the inventory cost, labor cost will be minimized and the utilization of time, financial resources and profit will be maximized. The optimum planning of resources also help the organizations to avoid wastage. A good forecasting technique can help the manager of a company to deal with the uncertainties. In this paper, we will work on such a planning fora fertilizer company in Bangladesh. To minimize the inventory cost, we will apply a new approach known as Artificial Neural Network (ANN), which is recently used for the problem of prediction and analyze the main characteristics of a system through an iterative training process. For this, we will first forecast the demand of fertilizer by using existing forecasting methods. We will then apply ANN for forecasting the demand of fertilizer of the company. We will also identify Economic Order Quantity (EOQ) to minimize total cost including inventory costs of the company. We use programming language MATLAB for analyzing different forecasting methods including ANN. Finally, we will use these results to find out the right forecasting technique for the fertilizer company with optimal inventory cost. Dhaka Univ. J. Sci. 69(3): 133-142, 2022 (June)
{"title":"An Artificial Neural Network Method for Managing Inventory of A Fertilizer Company in Bangladesh","authors":"M. B. Hasan, Lipi Akhter","doi":"10.3329/dujs.v69i3.60022","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60022","url":null,"abstract":"Business organizations are always facing uncertainties in demand, supply and inventories. For this, it is important for them to make the strategic plans to cope up with the uncertainty accordingly. To sustain, the business organizations must plan the future in such a way that the inventory cost, labor cost will be minimized and the utilization of time, financial resources and profit will be maximized. The optimum planning of resources also help the organizations to avoid wastage. A good forecasting technique can help the manager of a company to deal with the uncertainties. In this paper, we will work on such a planning fora fertilizer company in Bangladesh. To minimize the inventory cost, we will apply a new approach known as Artificial Neural Network (ANN), which is recently used for the problem of prediction and analyze the main characteristics of a system through an iterative training process. For this, we will first forecast the demand of fertilizer by using existing forecasting methods. We will then apply ANN for forecasting the demand of fertilizer of the company. We will also identify Economic Order Quantity (EOQ) to minimize total cost including inventory costs of the company. We use programming language MATLAB for analyzing different forecasting methods including ANN. Finally, we will use these results to find out the right forecasting technique for the fertilizer company with optimal inventory cost.\u0000Dhaka Univ. J. Sci. 69(3): 133-142, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76870293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60023
Md. Hasibul Islam, M. B. Hossain
The main objective of this research is to quantify evidence of the impact of green-space on fifteen health outcomes. Four databases- MEDLINE, EMBASE, AMED and CINAHL from January, 2000 to June, 2019 were searched. In this meta-analysis 63 observational studies were included for the investigation where 15 health outcomes (e.g., Type-2 Diabetes, Incidence of Hypertension, Incidence of Asthma, Stroke, Preterm Birth, Cardiovascular Mortality, All-cause Mortality, Salivary Cortisol and self-identified well-being etc) are considered. Our meta-analysis results revealed increased green-space exposure is associated with decreased heart rate (standardized mean difference (SMD)=−0.67), salivary cortisol (SMD = −0.31), along withreduced risk of preterm birth (OR = 0.87), type II diabetes (OR =0.76), hypertension (OR =0.77), coronary heart disease (OR = 0.85), all-cause mortality (OR = 0.69), cardiovascular mortality (OR =0.82), and an increased incidence of self-identified well-being (OR =1.15). Green-space exposure is found to be connected with the above mentioned health outcomes. Dhaka Univ. J. Sci. 69(3): 143-148, 2022 (June)
{"title":"The Benefits of Green-Space Exposure on Fifteen Health Outcomes: A Meta-Analysis","authors":"Md. Hasibul Islam, M. B. Hossain","doi":"10.3329/dujs.v69i3.60023","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60023","url":null,"abstract":"The main objective of this research is to quantify evidence of the impact of green-space on fifteen health outcomes. Four databases- MEDLINE, EMBASE, AMED and CINAHL from January, 2000 to June, 2019 were searched. In this meta-analysis 63 observational studies were included for the investigation where 15 health outcomes (e.g., Type-2 Diabetes, Incidence of Hypertension, Incidence of Asthma, Stroke, Preterm Birth, Cardiovascular Mortality, All-cause Mortality, Salivary Cortisol and self-identified well-being etc) are considered. Our meta-analysis results revealed increased green-space exposure is associated with decreased heart rate (standardized mean difference (SMD)=−0.67), salivary cortisol (SMD = −0.31), along withreduced risk of preterm birth (OR = 0.87), type II diabetes (OR =0.76), hypertension (OR =0.77), coronary heart disease (OR = 0.85), all-cause mortality (OR = 0.69), cardiovascular mortality (OR =0.82), and an increased incidence of self-identified well-being (OR =1.15). Green-space exposure is found to be connected with the above mentioned health outcomes.\u0000Dhaka Univ. J. Sci. 69(3): 143-148, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75584931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60025
Mohiuddin Muhi, S. Jahan, Md. Anwarul Islam Bhuiyan
This paper is focused on face recognition techniques in uncontrolled scenarios, specifically on the recognition of face images with blur effects. At first, the blur level of the testing image is determined using recently proposed blur metric. This blur metric value is used to blur the training set of gallery images using Gaussian filter. The blur level of training images is the same as that of the testing image. Two variants of Supervised Distance Preserving Projection (SDPP), SDPP as Semidefinite Least Square (SLS-SDPP) and Regularized Supervised Distance Preserving Projection (RSDPP), are used for extracting effective features of training and testing images. K-Nearest Neighbor classifier is used for matching. Numerical experiments were carried out on two benchmarking face data ORL and Yale. The performances of SLS-SDPP and RSDPP are compared with one of the leading methods Eigenface method. Experimental results show that the combination of blur metric and the feature extraction methods achieved outstanding performance in recognizing blur images of different levels and also outperforms the base methods and Eigenface method. Dhaka Univ. J. Sci. 69(3): 154-160, 2022 (June)
{"title":"Blur Face Recognition using Blur Metric and Some Variants of Supervised Distance Preserving Projection","authors":"Mohiuddin Muhi, S. Jahan, Md. Anwarul Islam Bhuiyan","doi":"10.3329/dujs.v69i3.60025","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60025","url":null,"abstract":"This paper is focused on face recognition techniques in uncontrolled scenarios, specifically on the recognition of face images with blur effects. At first, the blur level of the testing image is determined using recently proposed blur metric. This blur metric value is used to blur the training set of gallery images using Gaussian filter. The blur level of training images is the same as that of the testing image. Two variants of Supervised Distance Preserving Projection (SDPP), SDPP as Semidefinite Least Square (SLS-SDPP) and Regularized Supervised Distance Preserving Projection (RSDPP), are used for extracting effective features of training and testing images. K-Nearest Neighbor classifier is used for matching. Numerical experiments were carried out on two benchmarking face data ORL and Yale. The performances of SLS-SDPP and RSDPP are compared with one of the leading methods Eigenface method. Experimental results show that the combination of blur metric and the feature extraction methods achieved outstanding performance in recognizing blur images of different levels and also outperforms the base methods and Eigenface method.\u0000Dhaka Univ. J. Sci. 69(3): 154-160, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89984679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60021
M. Alauddin
Effects of temperature and solvents on the thermodynamical and electronic properties of N-acetyl-para-aminophenol (APAP) have been investigated using density functional theory (DFT) and time dependent density functional theory (TD-DFT). Calculated results shows that thermodynamic properties such as enthalpy (H), entropy (S) and specific heat capacity (Cv) are increased by the raising of temperature (100 K-1200 K) because of enhancing the intensities of molecular vibration. On the contrary, change of Gibb’s free energy (ΔG) has been decreased with the increase of temperature. FMO energy gap is enlarged by solvation and therefore APAP becomes more stable in solution especially in polar solvents. Moreover, solvation increases the magnitude of ionization potential, electron affinity, electronegativity, chemical potential and global hardness. Two UV absorption maxima (λmax1 and λmax2) are found at 243.08 nm and 193.85 nm which are originated from phenyl and amide chromophore, respectively. The calculated λmax1 and λmax2 agree quite well with the available experimental data. On the other hand, calculated results reveal that solvation blueshifts the electronic absorption spectraas well as enhances the absorption intensity significantly. Dhaka Univ. J. Sci. 69(3): 125-132, 2022 (June)
{"title":"The Effect of Temperature and Solvents on the Thermodynamical and Electronic Properties of N-acetyl-para-aminophenol (APAP): A Computational Study","authors":"M. Alauddin","doi":"10.3329/dujs.v69i3.60021","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60021","url":null,"abstract":"Effects of temperature and solvents on the thermodynamical and electronic properties of N-acetyl-para-aminophenol (APAP) have been investigated using density functional theory (DFT) and time dependent density functional theory (TD-DFT). Calculated results shows that thermodynamic properties such as enthalpy (H), entropy (S) and specific heat capacity (Cv) are increased by the raising of temperature (100 K-1200 K) because of enhancing the intensities of molecular vibration. On the contrary, change of Gibb’s free energy (ΔG) has been decreased with the increase of temperature. FMO energy gap is enlarged by solvation and therefore APAP becomes more stable in solution especially in polar solvents. Moreover, solvation increases the magnitude of ionization potential, electron affinity, electronegativity, chemical potential and global hardness. Two UV absorption maxima (λmax1 and λmax2) are found at 243.08 nm and 193.85 nm which are originated from phenyl and amide chromophore, respectively. The calculated λmax1 and λmax2 agree quite well with the available experimental data. On the other hand, calculated results reveal that solvation blueshifts the electronic absorption spectraas well as enhances the absorption intensity significantly.\u0000Dhaka Univ. J. Sci. 69(3): 125-132, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87072796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60026
M. Kamrujjaman, Md. Saiful Islam, Md. Shahidul Islam
This paper focuses on the global asymptotic properties of the SIR diffusive model for infectious diseases. Using the analytic technique with Lyapunov functions, we developed conditions for the global attractor of a unique disease steady-state and the disease free equilibrium. The most eminent refuge to the model is the direct Lyapunov mapping. We investigate the global well-posedness of the mathematical model, determine conditions on Ro for which non-trivial equilibrium states exist, and examine their global stability. We are interested in finding the model’s basic reproductive number, which determines whether the disease dies out or persists in the population. Finally, we consider a series of computational results to verify the theoretical results. The extensive numerical simulations show the dynamics of different population groups over time. The effects of different parameters on the compartments are shown in detail. The findings allude that the dynamics of the system are entirely estimated by the deterministic value Ro. Dhaka Univ. J. Sci. 69(3): 161-170, 2022 (June)
{"title":"Lyapunov Mappings and Analysis of a Nonlinear Spatio-temporal Epidemic Model","authors":"M. Kamrujjaman, Md. Saiful Islam, Md. Shahidul Islam","doi":"10.3329/dujs.v69i3.60026","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60026","url":null,"abstract":"This paper focuses on the global asymptotic properties of the SIR diffusive model for infectious diseases. Using the analytic technique with Lyapunov functions, we developed conditions for the global attractor of a unique disease steady-state and the disease free equilibrium. The most eminent refuge to the model is the direct Lyapunov mapping. We investigate the global well-posedness of the mathematical model, determine conditions on Ro for which non-trivial equilibrium states exist, and examine their global stability. We are interested in finding the model’s basic reproductive number, which determines whether the disease dies out or persists in the population. Finally, we consider a series of computational results to verify the theoretical results. The extensive numerical simulations show the dynamics of different population groups over time. The effects of different parameters on the compartments are shown in detail. The findings allude that the dynamics of the system are entirely estimated by the deterministic value Ro.\u0000Dhaka Univ. J. Sci. 69(3): 161-170, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83593419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60028
M. R. Molla, GM Bhuiyan, A. Ahmed
Using the orbital free ab-initio molecular dynamics (OF-AIMD) simulation scheme we have examined the static and dynamic properties of liquid Pt at the thermodynamic state near to its melting point. In this simulation scheme, the Hohenberg and Kohn orbital free density functional theory (OF-DFT) has been employed. In OF-DFT, we have estimated the electron-ion interaction by a local pseudopotential and also controlled the exchange-correlation energy functional by using the local density approximation (LDA). The static properties, for instance, static structure factor, S(q), pair correlation function, g(r), coordination number, Nc, and isothermal compressibility, κT, are examined. Using the familiar single-particle dynamics, the self-diffusion coefficient and self-intermediate scattering function are studied. It is found that the self-intermediate scattering function is controlled by the selfdiffusion coefficient. While for studying the collective dynamics of the system, we have calculated velocity of sound from the longitudinal dispersion relation and shear viscosity from the transverse current correlation function, JT(q, t). The OF-AIMD results are nicely fit with the theoretical and experimental results accessible to us for comparison. Dhaka Univ. J. Sci. 69(3): 179-185, 2022 (June)
{"title":"An Orbital Free Ab-initio Molecular Dynamics Study of Liquid Pt for Static and Dynamic Properties","authors":"M. R. Molla, GM Bhuiyan, A. Ahmed","doi":"10.3329/dujs.v69i3.60028","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60028","url":null,"abstract":"Using the orbital free ab-initio molecular dynamics (OF-AIMD) simulation scheme we have examined the static and dynamic properties of liquid Pt at the thermodynamic state near to its melting point. In this simulation scheme, the Hohenberg and Kohn orbital free density functional theory (OF-DFT) has been employed. In OF-DFT, we have estimated the electron-ion interaction by a local pseudopotential and also controlled the exchange-correlation energy functional by using the local density approximation (LDA). The static properties, for instance, static structure factor, S(q), pair correlation function, g(r), coordination number, Nc, and isothermal compressibility, κT, are examined. Using the familiar single-particle dynamics, the self-diffusion coefficient and self-intermediate scattering function are studied. It is found that the self-intermediate scattering function is controlled by the selfdiffusion coefficient. While for studying the collective dynamics of the system, we have calculated velocity of sound from the longitudinal dispersion relation and shear viscosity from the transverse current correlation function, JT(q, t). The OF-AIMD results are nicely fit with the theoretical and experimental results accessible to us for comparison.\u0000Dhaka Univ. J. Sci. 69(3): 179-185, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81552944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60032
Mohammad Abul Hossain, Shahidul Islam
This study presents the preparation of carbon nanoparticles (CNp) from incomplete combustion of the candle under a controlled air supply. The shape, size, and purity of the prepared carbon particles were investigated by using a scanning electron microscope (SEM), energy dispersive x-ray (EDX), X-ray diffractometer (XRD), Fourier transformed infrared spectroscopy (FTIR), and laser-induced breakdown spectroscopy (LIBS). Non-uniformed size of carbon particles was observed by SEM studies. Most of the particles are spherical and the diameter is in the range between 10 and 70 nm. The formation of carbon particles was affirmed by EDX analysis. Mostly amorphous carbon material, in addition to some hexagonal crystal lattice of graphite, was identified by XRD analysis. FTIR spectroscopic analysis indicated the possible presence of oxygen with carbon in the prepared nanoparticles. LIBS analysis confirmed the existence of trace amount (< 0.01 wt%) of oxygen as an impurity with carbon in the prepared nanoparticles. Dhaka Univ. J. Sci. 69(3): 212-217, 2022 (June)
{"title":"Preparation of Carbon Nanoparticles from Candle and Their Characterization by Advanced Spectroscopic Methods","authors":"Mohammad Abul Hossain, Shahidul Islam","doi":"10.3329/dujs.v69i3.60032","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60032","url":null,"abstract":"This study presents the preparation of carbon nanoparticles (CNp) from incomplete combustion of the candle under a controlled air supply. The shape, size, and purity of the prepared carbon particles were investigated by using a scanning electron microscope (SEM), energy dispersive x-ray (EDX), X-ray diffractometer (XRD), Fourier transformed infrared spectroscopy (FTIR), and laser-induced breakdown spectroscopy (LIBS). Non-uniformed size of carbon particles was observed by SEM studies. Most of the particles are spherical and the diameter is in the range between 10 and 70 nm. The formation of carbon particles was affirmed by EDX analysis. Mostly amorphous carbon material, in addition to some hexagonal crystal lattice of graphite, was identified by XRD analysis. FTIR spectroscopic analysis indicated the possible presence of oxygen with carbon in the prepared nanoparticles. LIBS analysis confirmed the existence of trace amount (< 0.01 wt%) of oxygen as an impurity with carbon in the prepared nanoparticles.\u0000Dhaka Univ. J. Sci. 69(3): 212-217, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91310193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60027
M. Ferdows, M. Murtaza, M. Bangalee, M. Hossain
Objective of this study is to analysis the MHD flow over a curved stretching surface. In this model we incorporated the radiation, mixed convection and partial slip parameter. Using a curvilinear coordinate system developed a mathematical model and the system of basic governing equations are converted into ordinary differential equations with appropriate transformations. The obtained results are solved by using bvp4c solver. The numerical; results for the velocity and temperature as well as the physical quantities such as skin friction and rate of heat transfer are determined and discussed through graph. Results shown that the velocity and temperature decreases with increasing values of curvature parameter and but for magnetic parameter velocity decreases whereas temperature profile increase. Comparison with previous literature are also shown in tabular form and found excellent agreement. Dhaka Univ. J. Sci. 69(3): 171-178, 2022 (June)
{"title":"Effects of Mixed Convection and Radiation Parameter on MHD Heat Transfer Flow over a Curved Stretching Sheet","authors":"M. Ferdows, M. Murtaza, M. Bangalee, M. Hossain","doi":"10.3329/dujs.v69i3.60027","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60027","url":null,"abstract":"Objective of this study is to analysis the MHD flow over a curved stretching surface. In this model we incorporated the radiation, mixed convection and partial slip parameter. Using a curvilinear coordinate system developed a mathematical model and the system of basic governing equations are converted into ordinary differential equations with appropriate transformations. The obtained results are solved by using bvp4c solver. The numerical; results for the velocity and temperature as well as the physical quantities such as skin friction and rate of heat transfer are determined and discussed through graph. Results shown that the velocity and temperature decreases with increasing values of curvature parameter and but for magnetic parameter velocity decreases whereas temperature profile increase. Comparison with previous literature are also shown in tabular form and found excellent agreement.\u0000Dhaka Univ. J. Sci. 69(3): 171-178, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75347828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60031
Md Shakil Hossain, Md Abdus Samad, Md. Saddam Hossain, SM Arif Hossen, Md. Asraful Islam, S. Hassan
Simulation of Super Cyclonic Storm (SuCS) Amphan (2020) has been carried out as a case study to analyze the sensitivity of Initial Condition (IC) and Horizontal Resolution (HR) on the intensity, track, and landfall predictions of the Tropical Cyclones (TCs). The results suggest that the IC and HR have a significant impact on TC simulations. Diminishing the HR in simulation results in a comparatively higher severity of the system. The simulation with a reduced lead time and a comparatively smaller HR has forecasted the Minimum Central Pressure (MCP) distribution reasonably well. In comparison to the observations, the reduced lead time model run with higher resolution has forecasted the Maximum Sustained Wind Speed (MSWS) distribution precisely. According to the statistical analysis, the continual reduction of lead time in simulation with the HR of 27 km has simulated better track and landfall positions than other resolutions. Thus, the combination of reduced lead time and higher resolution in simulation may be considered for the proper track and landfall forecasting. Dhaka Univ. J. Sci. 69(3): 202-211, 2022 (June)
{"title":"The Sensitivity of Initial Condition and Horizontal Resolution on Simulation of Tropical Cyclone Amphan over the Bay of Bengal using WRF-ARW Model","authors":"Md Shakil Hossain, Md Abdus Samad, Md. Saddam Hossain, SM Arif Hossen, Md. Asraful Islam, S. Hassan","doi":"10.3329/dujs.v69i3.60031","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60031","url":null,"abstract":"Simulation of Super Cyclonic Storm (SuCS) Amphan (2020) has been carried out as a case study to analyze the sensitivity of Initial Condition (IC) and Horizontal Resolution (HR) on the intensity, track, and landfall predictions of the Tropical Cyclones (TCs). The results suggest that the IC and HR have a significant impact on TC simulations. Diminishing the HR in simulation results in a comparatively higher severity of the system. The simulation with a reduced lead time and a comparatively smaller HR has forecasted the Minimum Central Pressure (MCP) distribution reasonably well. In comparison to the observations, the reduced lead time model run with higher resolution has forecasted the Maximum Sustained Wind Speed (MSWS) distribution precisely. According to the statistical analysis, the continual reduction of lead time in simulation with the HR of 27 km has simulated better track and landfall positions than other resolutions. Thus, the combination of reduced lead time and higher resolution in simulation may be considered for the proper track and landfall forecasting.\u0000Dhaka Univ. J. Sci. 69(3): 202-211, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81837245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-04DOI: 10.3329/dujs.v69i3.60033
Farhana Hossain, M. Rahman, M. Hossain
Composites of ZnO-TiO2 with different ratios have been prepared by heating the mixtures at different temperatures and characterized by SEM, FT-IR and XRD techniques. The results from these techniques support the formation of the composites. These composites have been applied for photodegradation of a textile dye, orange G (OG). The composite with a composition of ZnO:TiO2 = 75:25 prepared at 500 oC has been found to show the highest catalytic efficiency. The experiments have been carried out by varying the experimental conditions to optimize them. The best catalytic performance has been found with 0.25 g/100 mL of the catalyst, 1.02× 10-4 M initial concentration of OG and the UV light source. A mechanism for photocatalytic degradation of dye has been proposed. Dhaka Univ. J. Sci. 69(3): 218-224, 2022 (June)
{"title":"ZnO-TiO2 Composite Mediated Photocatalytic Degradation of Orange G from Aqueous Solution","authors":"Farhana Hossain, M. Rahman, M. Hossain","doi":"10.3329/dujs.v69i3.60033","DOIUrl":"https://doi.org/10.3329/dujs.v69i3.60033","url":null,"abstract":"Composites of ZnO-TiO2 with different ratios have been prepared by heating the mixtures at different temperatures and characterized by SEM, FT-IR and XRD techniques. The results from these techniques support the formation of the composites. These composites have been applied for photodegradation of a textile dye, orange G (OG). The composite with a composition of ZnO:TiO2 = 75:25 prepared at 500 oC has been found to show the highest catalytic efficiency. The experiments have been carried out by varying the experimental conditions to optimize them. The best catalytic performance has been found with 0.25 g/100 mL of the catalyst, 1.02× 10-4 M initial concentration of OG and the UV light source. A mechanism for photocatalytic degradation of dye has been proposed.\u0000Dhaka Univ. J. Sci. 69(3): 218-224, 2022 (June)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73790059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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