Pub Date : 2022-12-18DOI: 10.3329/dujs.v70i2.62598
Md. Akter Hosen, Rownak Jahan Tamanna
For normal physiologic functions, Iodine is necessary in small amount. It sanctions the thyroid gland to creates thyroid hormones, which is essential for mature and enlargement of the brain, body structures and central nervous system (CNS). In developing countries mental impediment and insufficient commercial performance are one of the results of iodine insufficiency issue. Globally, universal salt iodization has been executed to eradicate iodine insufficiency. However, the sufficiency of iodine in salts needs close observing to match its deliberated target. From this study,we find the adequately iodized salt consumption is associated with some demographic features such as, education, region, wealth index, access to mass-media etc. These findings are important for policy makers and Government as they should take necessary steps to increase the accession to education and media and also take realistic plan to increase the availability of adequately salt in Bangladesh. Dhaka Univ. J. Sci. 70(2): 1-7, 2022 (July)
{"title":"Availability of Adequately Iodized Salt Consumption and its Association with Socio-Economic Factors in Bangladesh","authors":"Md. Akter Hosen, Rownak Jahan Tamanna","doi":"10.3329/dujs.v70i2.62598","DOIUrl":"https://doi.org/10.3329/dujs.v70i2.62598","url":null,"abstract":"For normal physiologic functions, Iodine is necessary in small amount. It sanctions the thyroid gland to creates thyroid hormones, which is essential for mature and enlargement of the brain, body structures and central nervous system (CNS). In developing countries mental impediment and insufficient commercial performance are one of the results of iodine insufficiency issue. Globally, universal salt iodization has been executed to eradicate iodine insufficiency. However, the sufficiency of iodine in salts needs close observing to match its deliberated target. From this study,we find the adequately iodized salt consumption is associated with some demographic features such as, education, region, wealth index, access to mass-media etc. These findings are important for policy makers and Government as they should take necessary steps to increase the accession to education and media and also take realistic plan to increase the availability of adequately salt in Bangladesh.\u0000Dhaka Univ. J. Sci. 70(2): 1-7, 2022 (July)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89882668","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 : 2022-12-18DOI: 10.3329/dujs.v70i2.62600
DM Zunayed Kamal Nibir, S. Nasrin, S. M. S. Rana
In this paper we introduce an efficient variant of the RSA cryptosystem which will need lesser memory for key storage which is lessen the computational cost. Introduction of the RSA cryptosystem by Rivest, Shamir, and Adleman in 1978 was a revolutionary step in cryptography. The regular RSA system needs huge cost for decryption due to large size of the private decryption key. The proposed variant will be a solution to this conundrum. Dhaka Univ. J. Sci. 70(2): 15-17, 2022 (July)
{"title":"A Variant of the RSA Cryptosystem with Smaller Keys","authors":"DM Zunayed Kamal Nibir, S. Nasrin, S. M. S. Rana","doi":"10.3329/dujs.v70i2.62600","DOIUrl":"https://doi.org/10.3329/dujs.v70i2.62600","url":null,"abstract":"In this paper we introduce an efficient variant of the RSA cryptosystem which will need lesser memory for key storage which is lessen the computational cost. Introduction of the RSA cryptosystem by Rivest, Shamir, and Adleman in 1978 was a revolutionary step in cryptography. The regular RSA system needs huge cost for decryption due to large size of the private decryption key. The proposed variant will be a solution to this conundrum.\u0000Dhaka Univ. J. Sci. 70(2): 15-17, 2022 (July)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87042047","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 : 2022-12-18DOI: 10.3329/dujs.v70i2.62601
Md Shapan Miah, Khondokar M. Ahmed
The main aim of this article to study about vector fields of manifold and how these vector fields will be Killing and Conformal Killing vector fields. Conformal transformation of Weyl rescaling which is conformally related to metrices from g to g, Levi-Civita connection Δ , Lie derivative, torsion with tensor concept of manifold N in a multi-linear map have been treated in this paper. Finally, we have been proved Example 3.02and established the theorem 6.02 on Conformal Killing vector fields. Dhaka Univ. J. Sci. 70(2): 18-22, 2022 (July)
{"title":"Conformal Killing Vector Fields of Riemannian Manifolds","authors":"Md Shapan Miah, Khondokar M. Ahmed","doi":"10.3329/dujs.v70i2.62601","DOIUrl":"https://doi.org/10.3329/dujs.v70i2.62601","url":null,"abstract":"The main aim of this article to study about vector fields of manifold and how these vector fields will be Killing and Conformal Killing vector fields. Conformal transformation of Weyl rescaling which is conformally related to metrices from g to g, Levi-Civita connection Δ , Lie derivative, torsion with tensor concept of manifold N in a multi-linear map have been treated in this paper. Finally, we have been proved Example 3.02and established the theorem 6.02 on Conformal Killing vector fields.\u0000Dhaka Univ. J. Sci. 70(2): 18-22, 2022 (July)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78170843","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 : 2022-12-18DOI: 10.3329/dujs.v70i2.62608
Ajadur Rahman Shakil, Most Laboni Begum, Md. Aftab Ali Shaikh, S. Sultana, M. Rahman, Md. Mahamudul Hasan Rumon, C. Roy, Md Anamul Haque
In this study, a hydrogel composite based on natural jute fiber (JF) has been prepared and employed for the removal of methylene blue (MB) dye from aqueous solution. Polyacrylamide (PAAm) hydrogel was synthesized by thermal polymerization in presence of N,N□-methylene bisacrylamide (MBAA) as the cross-linker and potassium per sulfate (KPS) as the initiator. JF reinforced hydrogel (JFRH) composite was prepared by incorporating JF into PAAm matrix prior to the polymerization. The prepared JFRH was characterized by FTIR spectroscopy and scanning electron microscope. It was found that, JFRH composite demonstrated strong mechanical properties with a compressive strength of 1.5 MPa at a deformation of above 80%. The prepared JFRH composite can remove more than 90% of MB from an aqueous solution and be separated easily from the solution after the adsorption process. Therefore, the synthesized JF based hydrogel composite could significantly expand the use of our natural golden fiber for reinforcement of composite materials and removal of dyes from water bodies. Dhaka Univ. J. Sci. 70(2): 59-64, 2022 (July)
{"title":"Jute Fiber Reinforced Hydrogel Composite for Removal of Methylene Blue Dye from Water","authors":"Ajadur Rahman Shakil, Most Laboni Begum, Md. Aftab Ali Shaikh, S. Sultana, M. Rahman, Md. Mahamudul Hasan Rumon, C. Roy, Md Anamul Haque","doi":"10.3329/dujs.v70i2.62608","DOIUrl":"https://doi.org/10.3329/dujs.v70i2.62608","url":null,"abstract":"In this study, a hydrogel composite based on natural jute fiber (JF) has been prepared and employed for the removal of methylene blue (MB) dye from aqueous solution. Polyacrylamide (PAAm) hydrogel was synthesized by thermal polymerization in presence of N,N□-methylene bisacrylamide (MBAA) as the cross-linker and potassium per sulfate (KPS) as the initiator. JF reinforced hydrogel (JFRH) composite was prepared by incorporating JF into PAAm matrix prior to the polymerization. The prepared JFRH was characterized by FTIR spectroscopy and scanning electron microscope. It was found that, JFRH composite demonstrated strong mechanical properties with a compressive strength of 1.5 MPa at a deformation of above 80%. The prepared JFRH composite can remove more than 90% of MB from an aqueous solution and be separated easily from the solution after the adsorption process. Therefore, the synthesized JF based hydrogel composite could significantly expand the use of our natural golden fiber for reinforcement of composite materials and removal of dyes from water bodies.\u0000Dhaka Univ. J. Sci. 70(2): 59-64, 2022 (July)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81364834","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 : 2022-12-18DOI: 10.3329/dujs.v70i2.62603
Md Galib Mahmud, M. S. Islam, Tanvir Ahmed, M. E. Halim, M. Ismail
Globally, scrap tyres are increasing due to the increased number of vehicles. In contrast, in the recent years, alternatives to fossil fuels are exploring to overcome the fossil fuel crisis. In this study, pyrolysis of bicycle and rickshaw tyres wastes was conducted and parametric effects (e.g., the effect of temperature, feed size and apparent vapor residence time etc.) on the pyrolysis product yields were determined. A fixed bed electric heating reactor was used for pyrolysis at 400 - 550 oC, maintaining various particles sizes and a constant heating rate of 20oC/min. The optimum Tyre Pyrolysis Oil (TPO) yield of 42 wt.% was obtained at 500 oC for a sample size of 4.0 cm3. The fuel properties (e.g., density, viscosity, calorific value, flash point, pour point, sulphur content, ash content etc.), functional group studies of the TPO were determined and was compared with the conventional fuel and with international standards. The physico-chemical properties of TPO confirm the use of TPO as furnace oil in various industrial processes. The fractionation of bio-oil gives various value added products including bio-gasoline, bio-kerosene and others chemicals. The commercial implementation of the pyrolysis and follow-up technologies for waste tires processing will allow energetic valorization of waste tyres in Bangladesh. Dhaka Univ. J. Sci. 70(2): 29-34, 2022 (July)
{"title":"Production, Characterization and Evaluation of Pyrolysis Oil from Tyre Wastes Available in Bangladesh","authors":"Md Galib Mahmud, M. S. Islam, Tanvir Ahmed, M. E. Halim, M. Ismail","doi":"10.3329/dujs.v70i2.62603","DOIUrl":"https://doi.org/10.3329/dujs.v70i2.62603","url":null,"abstract":"Globally, scrap tyres are increasing due to the increased number of vehicles. In contrast, in the recent years, alternatives to fossil fuels are exploring to overcome the fossil fuel crisis. In this study, pyrolysis of bicycle and rickshaw tyres wastes was conducted and parametric effects (e.g., the effect of temperature, feed size and apparent vapor residence time etc.) on the pyrolysis product yields were determined. A fixed bed electric heating reactor was used for pyrolysis at 400 - 550 oC, maintaining various particles sizes and a constant heating rate of 20oC/min. The optimum Tyre Pyrolysis Oil (TPO) yield of 42 wt.% was obtained at 500 oC for a sample size of 4.0 cm3. The fuel properties (e.g., density, viscosity, calorific value, flash point, pour point, sulphur content, ash content etc.), functional group studies of the TPO were determined and was compared with the conventional fuel and with international standards. The physico-chemical properties of TPO confirm the use of TPO as furnace oil in various industrial processes. The fractionation of bio-oil gives various value added products including bio-gasoline, bio-kerosene and others chemicals. The commercial implementation of the pyrolysis and follow-up technologies for waste tires processing will allow energetic valorization of waste tyres in Bangladesh.\u0000Dhaka Univ. J. Sci. 70(2): 29-34, 2022 (July)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"14 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72741121","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 : 2022-12-18DOI: 10.3329/dujs.v70i2.62606
Mohsina Jiban Dyuti, R. Afroz, M. Shoeb
The objective of the study was to investigate Limonia acidissima L. (wood apple) to determine the moisture and ash content, total amount of carbohydrates, fatty acid compositions, the quantity of protein and micronutrients (Na, K, Zn, Fe) present in wood apple grown in Bangladesh. FT-IR spectroscopy was used to pinpoint many biologically significant functional groups. The moisture and ash content obtained were 74.02 and 25.44%, respectively. Carbohydrate content determined by ultraviolet-visible (UV-Visible) spectroscopic method was 16.14 g per 100 g of dried fruit sample. The fatty acids were identified by Gas Chromatography-Flame Ionization Detector (GC-FID). The relative percentage of bound fatty acids mainly palmitoleic acid, octadecanoic acid, cis-9-oleic acid and octanoic acid were 17.33, 15.09, 15.09 and 45.09%, respectively. The amount of protein was 5.11%. The micronutrients such as Na, K, Zn, Fe present in the edible portion of wood apple measured by atomic absorption spectroscopy (AAS) were 10.40, 58.24, 0.37 and 1.67 mg per 100 g of dried sample, respectively. The fruit has long been utilized in herbal medicines and is eaten raw or processed into various products to prevent noncommunicable diseases and micronutrient deficiencies. Dhaka Univ. J. Sci. 70(2): 48-52, 2022 (July)
本研究旨在研究孟加拉国木苹果的水分和灰分含量、碳水化合物总量、脂肪酸组成、蛋白质和微量元素(Na、K、Zn、Fe)的含量。FT-IR光谱被用来确定许多生物学上重要的官能团。所得水分和灰分含量分别为74.02和25.44%。紫外-可见光谱法测定的碳水化合物含量为16.14 g / 100g。采用气相色谱-火焰离子化检测器(GC-FID)对脂肪酸进行鉴定。结合脂肪酸主要为棕榈油酸、十八烷酸、顺式9-油酸和辛酸的相对比例分别为17.33、15.09、15.09和45.09%。蛋白质含量为5.11%。原子吸收光谱法测定木苹果可食部分微量元素Na、K、Zn、Fe含量分别为10.40、58.24、0.37和1.67 mg / 100 g。长期以来，这种水果一直被用作草药，生吃或加工成各种产品，以预防非传染性疾病和微量营养素缺乏症。达卡大学学报(自然科学版)，70(2):48- 52,2022 (7)
{"title":"Assessment of Nutritional Value of Limonia acidissima L. (Wood Apple)","authors":"Mohsina Jiban Dyuti, R. Afroz, M. Shoeb","doi":"10.3329/dujs.v70i2.62606","DOIUrl":"https://doi.org/10.3329/dujs.v70i2.62606","url":null,"abstract":"The objective of the study was to investigate Limonia acidissima L. (wood apple) to determine the moisture and ash content, total amount of carbohydrates, fatty acid compositions, the quantity of protein and micronutrients (Na, K, Zn, Fe) present in wood apple grown in Bangladesh. FT-IR spectroscopy was used to pinpoint many biologically significant functional groups. The moisture and ash content obtained were 74.02 and 25.44%, respectively. Carbohydrate content determined by ultraviolet-visible (UV-Visible) spectroscopic method was 16.14 g per 100 g of dried fruit sample. The fatty acids were identified by Gas Chromatography-Flame Ionization Detector (GC-FID). The relative percentage of bound fatty acids mainly palmitoleic acid, octadecanoic acid, cis-9-oleic acid and octanoic acid were 17.33, 15.09, 15.09 and 45.09%, respectively. The amount of protein was 5.11%. The micronutrients such as Na, K, Zn, Fe present in the edible portion of wood apple measured by atomic absorption spectroscopy (AAS) were 10.40, 58.24, 0.37 and 1.67 mg per 100 g of dried sample, respectively. The fruit has long been utilized in herbal medicines and is eaten raw or processed into various products to prevent noncommunicable diseases and micronutrient deficiencies.\u0000Dhaka Univ. J. Sci. 70(2): 48-52, 2022 (July)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"165 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73138541","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 : 2022-07-24DOI: 10.3329/dujs.v70i1.60374
M. Rahman, M. Bashar, N. Islam
Fabrication of environmentally safe C2ZnSnS4 (CZTS) photovoltaic thin films of pure kesterite state is crucial. We have preparedCZTS thin films by sol-gel dip-coating process from chloride-based chemicals. After vacuum-annealed at 550°C, the optical andstructural characters of the films were further examined by UV–vis spectroscopy, X-ray diffraction (XRD), scanning electronmicroscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) methods. The CZTS films offered high optical absorption(0.4x104cm-1) and nearly optimum bandgap energy (1.65e V). X-ray diffraction examination confirmed the kesterite structure offilms. Scanning electron micrograph affirmed the creation of jam-packed, condensed and granulated CZTS films. The thin filmdisplayed intermittent disposal of agglomerated particles with clear-cut edges. The energy dispersive X-ray spectroscopy study gavethe stoichiometric ratio as Cu: Zn: Sn: S= 2.2: 1.4: 1: 5.1. Dhaka Univ. J. Sci. 70(1): 1-7, 2022 (January)
{"title":"Optical and Structural Study of the CZTS (Cu2ZnSnS4) Thin Film for Solar Cell Derived from the Chloride-Based sol-gel Precursor Solution","authors":"M. Rahman, M. Bashar, N. Islam","doi":"10.3329/dujs.v70i1.60374","DOIUrl":"https://doi.org/10.3329/dujs.v70i1.60374","url":null,"abstract":"Fabrication of environmentally safe C2ZnSnS4 (CZTS) photovoltaic thin films of pure kesterite state is crucial. We have preparedCZTS thin films by sol-gel dip-coating process from chloride-based chemicals. After vacuum-annealed at 550°C, the optical andstructural characters of the films were further examined by UV–vis spectroscopy, X-ray diffraction (XRD), scanning electronmicroscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) methods. The CZTS films offered high optical absorption(0.4x104cm-1) and nearly optimum bandgap energy (1.65e V). X-ray diffraction examination confirmed the kesterite structure offilms. Scanning electron micrograph affirmed the creation of jam-packed, condensed and granulated CZTS films. The thin filmdisplayed intermittent disposal of agglomerated particles with clear-cut edges. The energy dispersive X-ray spectroscopy study gavethe stoichiometric ratio as Cu: Zn: Sn: S= 2.2: 1.4: 1: 5.1. \u0000Dhaka Univ. J. Sci. 70(1): 1-7, 2022 (January)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91294688","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}
Fourteen tropical fruit items were collected from different industrial sites of the Dhaka and Chattogram region, Bangladesh todetermine toxic heavy metal contents. This study aimed at the assessment of the distribution of heavy metals (As, Pb and Cr) as wellas comparison of their level among different locations. The fruit items were analyzed for the quantification of the selected heavymetals using Atomic Absorption Spectrophotometer (AAS). The range of lead, chromium and arsenic in the fruit items were 1.12± 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 thelevel of toxic metals (As, Cr) in almost all fruit samples were within tolerable limit whereas the level of Pd in all of the fruit samplesexceeded the acceptable limits of WHO standard value. It was also observed from the results obtained that the concentration of themetals found in the samples from Dhaka regions were considerably higher than that of Chattogram. These metal contributors mainlyarising from anthropogenic sources including industrial wastes, automobile emissions, use of fertilizers, pesticides and herbicides inagriculture, paints, sewage and waste disposal. The extended level of these metals causing environmental pollution is hazardous sinceplants accumulate them. Subsequently, crops uptaking these heavy metals consumed by humans and animals which is detrimental tohealth. It is therefore very important that necessary actions need to be taken to monitor the level of these deleterious elements in foodplants. In decision making, planning and risk assessing this present study will play significant role. Dhaka Univ. J. Sci. 70(1): 22-27, 2022 (January)
{"title":"Determination of Toxic Heavy Metal Contents of Some Selected Tropical Fruits Grown in Industrial Areas of Bangladesh","authors":"Md. Ashraful Islam, Maksuda Parvin, Md. Fahad Bin Quader, Md. Shakhawat Hossain","doi":"10.3329/dujs.v70i1.60377","DOIUrl":"https://doi.org/10.3329/dujs.v70i1.60377","url":null,"abstract":"Fourteen tropical fruit items were collected from different industrial sites of the Dhaka and Chattogram region, Bangladesh todetermine toxic heavy metal contents. This study aimed at the assessment of the distribution of heavy metals (As, Pb and Cr) as wellas comparison of their level among different locations. The fruit items were analyzed for the quantification of the selected heavymetals using Atomic Absorption Spectrophotometer (AAS). The range of lead, chromium and arsenic in the fruit items were 1.12± 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 thelevel of toxic metals (As, Cr) in almost all fruit samples were within tolerable limit whereas the level of Pd in all of the fruit samplesexceeded the acceptable limits of WHO standard value. It was also observed from the results obtained that the concentration of themetals found in the samples from Dhaka regions were considerably higher than that of Chattogram. These metal contributors mainlyarising from anthropogenic sources including industrial wastes, automobile emissions, use of fertilizers, pesticides and herbicides inagriculture, paints, sewage and waste disposal. The extended level of these metals causing environmental pollution is hazardous sinceplants accumulate them. Subsequently, crops uptaking these heavy metals consumed by humans and animals which is detrimental tohealth. It is therefore very important that necessary actions need to be taken to monitor the level of these deleterious elements in foodplants. In decision making, planning and risk assessing this present study will play significant role. \u0000Dhaka Univ. J. Sci. 70(1): 22-27, 2022 (January)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87195991","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 : 2022-07-24DOI: 10.3329/dujs.v70i1.60379
M. Rahman, M. Rabbani
The use of LED luminaries is increasing day by day and the traditional sources of light are being replaced by this semiconductortechnology. In this study, the interactions of Red, Green and Blue LED light with human-eye are considered to model the temperatureprofile due to the attenuation in the ocular media. The simulation has been done using COMSOL Multiphysics 5.3. The results of thestudy show that Blue LED light causes temperature rise more than the other two colours of light. At the tip of the corneal surface,blue LED light causes the temperature to rise by 0.91⁰C whereas the rise of temperature for green and red LED are 0.85⁰C and0.46⁰C respectively. However, the temperature at the posterior layers of the eye, sclera, choroid and retina undergoes little thermaleffects due to LED light owing to the fact that the heat-flux due blood flow is dominant in that region. Dhaka Univ. J. Sci. 70(1): 34-41, 2022 (January)
{"title":"Simulation Based Temperature Profiling of Human Eye due to the Exposure of LED Light","authors":"M. Rahman, M. Rabbani","doi":"10.3329/dujs.v70i1.60379","DOIUrl":"https://doi.org/10.3329/dujs.v70i1.60379","url":null,"abstract":"The use of LED luminaries is increasing day by day and the traditional sources of light are being replaced by this semiconductortechnology. In this study, the interactions of Red, Green and Blue LED light with human-eye are considered to model the temperatureprofile due to the attenuation in the ocular media. The simulation has been done using COMSOL Multiphysics 5.3. The results of thestudy show that Blue LED light causes temperature rise more than the other two colours of light. At the tip of the corneal surface,blue LED light causes the temperature to rise by 0.91⁰C whereas the rise of temperature for green and red LED are 0.85⁰C and0.46⁰C respectively. However, the temperature at the posterior layers of the eye, sclera, choroid and retina undergoes little thermaleffects due to LED light owing to the fact that the heat-flux due blood flow is dominant in that region. \u0000Dhaka Univ. J. Sci. 70(1): 34-41, 2022 (January)","PeriodicalId":11280,"journal":{"name":"Dhaka University Journal of Science","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89226514","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 : 2022-07-24DOI: 10.3329/dujs.v70i1.60383
M. Momen, M. Rahman, H. Begum, M. Hossain
In the present investigation, Cu(II) doped TiO2 was prepared by a precipitation method. The precipitate was calcined at 300 ºC for2 hours. The prepared doped catalyst was characterized by scanning electron microscope (SEM), energy dispersive X-ray (EDX)spectroscopy and X-ray diffractometry (XRD). SEM images revealed that the morphology of the doped catalyst was different fromthat of TiO2. Elemental analysis was accomplished by EDX that indicated the presence of Cu, Ti and O atoms in the prepared sample.XRD analysis confirmed that TiO2 was present as anatase with almost no distortion in peak position due to the presence of Cu(II)in some interstitial sites. Photodegradation of remazol black B (RBB) was carried out at different experimental conditions underdifferent light sources. The catalytic efficiency of Cu(II) doped TiO2 increased up to a certain dosage then reduced with a furtherincrease in the amount of photocatalyst. The optimum conditions for degradation was found at pH 3.0 under UV light. Under theseexperimental conditions, Cu(II) doped TiO2 degraded 98.8% of RBB, on the other hand, undoped TiO2 degraded only 80.0% of RBB. Dhaka Univ. J. Sci. 70(1): 64-69, 2022 (January)
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