Y.M.C.D. Jayathilaka, K. Perera, K. Vidanapathirana, L. Bandara
Portable electronic device industry is vastly developing over the last few years. As electrochemical batteries are suitable power sources for portable devices, demand for reliable and efficient batteries have also been increased. Since liquid electrolytes can cause several safety hazards due to leaking of the electrolyte, studies on gel polymer electrolytes have been able to attract many researchers. In this research work, a gel polymer electrolyte based primary cell was fabricated and discharge characteristics were studied. To prepare the gel polymer electrolyte, Polymethylmethacrylate (PMMA), Ethylene Carbonate (EC), Propylene Carbonate (PC) and Copper trifluoromethanesulfonate (Cu(CF 3 SO 3 ) 2 - CuTf) were used. Gel polymer electrolyte sample which contained 22.5% PMMA: 30% EC: 30% PC: 17.5% CuTf showed a conductivity of 2.34 10 -3 S cm -1 at room temperature with an appreciable mechanical stability. Primary cell with Cu and Mg electrodes showed 1.73 V open circuit potential, 131 µA h capacity and 1.13 mA short circuit current. DOI: http://dx.doi.org/10.4038/sljp.v15i0.6686 Sri Lankan Journal of Physics, Vol. 15 (2014) 45-51
{"title":"Evaluation of a copper based gel polymer electrolyte and its performance in a primary cell","authors":"Y.M.C.D. Jayathilaka, K. Perera, K. Vidanapathirana, L. Bandara","doi":"10.4038/SLJP.V15I0.6686","DOIUrl":"https://doi.org/10.4038/SLJP.V15I0.6686","url":null,"abstract":"Portable electronic device industry is vastly developing over the last few years. As electrochemical batteries are suitable power sources for portable devices, demand for reliable and efficient batteries have also been increased. Since liquid electrolytes can cause several safety hazards due to leaking of the electrolyte, studies on gel polymer electrolytes have been able to attract many researchers. In this research work, a gel polymer electrolyte based primary cell was fabricated and discharge characteristics were studied. To prepare the gel polymer electrolyte, Polymethylmethacrylate (PMMA), Ethylene Carbonate (EC), Propylene Carbonate (PC) and Copper trifluoromethanesulfonate (Cu(CF 3 SO 3 ) 2 - CuTf) were used. Gel polymer electrolyte sample which contained 22.5% PMMA: 30% EC: 30% PC: 17.5% CuTf showed a conductivity of 2.34 10 -3 S cm -1 at room temperature with an appreciable mechanical stability. Primary cell with Cu and Mg electrodes showed 1.73 V open circuit potential, 131 µA h capacity and 1.13 mA short circuit current. DOI: http://dx.doi.org/10.4038/sljp.v15i0.6686 Sri Lankan Journal of Physics, Vol. 15 (2014) 45-51","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"30 1","pages":"45"},"PeriodicalIF":0.0,"publicationDate":"2015-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90472058","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}
R.C.L. De Silva, M. Jayaweera, V. Perera, I. Jayarathna, S. Rosa
The initial research on rechargeable batteries started focusing on both Lithium and Sodium but Lithium was more attracted because of its higher energy density. Later considering the cost of lithium, research has been directed to explore the possibility of using Sodium for rechargeable batteries because of its high abundance and low cost compared to Lithium. In this study we focuses on sodium Nickel oxide as the cathode material of the sodium iron rechargeable battery and tests were carried out to find the formation of crystal structure. Synthesis of Na x NiO 2 nonporous active material were made using solid state reactions at 700 ° C and the material development was studied by XRD characterizing technique. The developed Na x NiO 2 was used as the active cathode material in a rechargeable half cell. The characterization confirmed the crystal structure of NaNiO 2 to be monoclinic, and also its surface morphology. Electron transition status test revealed the specific energy band gap to be 5.16 eV. Charge transfer resistance of the cathode material obtained was 13,121 Ω. The further investigations on charge discharge revealed the maximum efficient charging rate per gram as 7.5 mA for 0.12 hours and maximum rate of discharge for maximum charge retention as 25 mA rate of charge per gram of Na x NiO 2 which was the active material of the rechargeable cell. The charge discharge cyclability was tested for Sodium Nickel Oxide with 0.2 mA constant current for both charging and discharging. A voltage of 2.34 V was observed as the open voltage (no load) at the beginning and the half cell showed more than 180 charge-discharge cycles in performance including a rest time of one minute for each cycle. This confirmed that the battery is able to hold a fairly high reversibility. DOI: http://dx.doi.org/10.4038/sljp.v15i0.8021 Sri Lankan Journal of Physics, Vol. 15 (2014) 19-29
对可充电电池的最初研究主要集中在锂电池和钠电池上，但锂电池因其更高的能量密度而更受欢迎。后来考虑到锂的成本，研究人员开始探索将钠用于可充电电池的可能性，因为与锂相比，钠的丰度高，成本低。本研究以氧化镍钠作为铁钠可充电电池的正极材料，并对其晶体结构的形成进行了测试。在700℃下采用固相反应合成了Na x nio2无孔活性材料，并采用XRD表征技术对材料的发育进行了研究。在可充电半电池中，将所制备的Na x nio2用作活性正极材料。表征证实了纳米二氧化硅的晶体结构和表面形貌均为单斜晶。电子跃迁状态测试表明，比能带隙为5.16 eV。所得正极材料的电荷转移电阻为13121 Ω。进一步的充放电研究表明，每克电池的最大有效充电速率为7.5 mA，充电时间为0.12小时，最大电荷保留率为25 mA，每克电池的活性材料Na x nio2的充电速率为25 mA。在0.2 mA恒流条件下，对氧化镍钠的充放电循环性能进行了测试。开始时的开电压为2.34 V(空载)，半电池的充放电循环次数超过180次，每次循环休息时间为1分钟。这证实了电池能够保持相当高的可逆性。DOI: http://dx.doi.org/10.4038/sljp.v15i0.8021斯里兰卡物理杂志，Vol. 15 (2014) 19-29
{"title":"Sodium nickel oxide nanoporous cathodes used for sodium-ion rechargeable batteries","authors":"R.C.L. De Silva, M. Jayaweera, V. Perera, I. Jayarathna, S. Rosa","doi":"10.4038/SLJP.V15I0.8021","DOIUrl":"https://doi.org/10.4038/SLJP.V15I0.8021","url":null,"abstract":"The initial research on rechargeable batteries started focusing on both Lithium and Sodium but Lithium was more attracted because of its higher energy density. Later considering the cost of lithium, research has been directed to explore the possibility of using Sodium for rechargeable batteries because of its high abundance and low cost compared to Lithium. In this study we focuses on sodium Nickel oxide as the cathode material of the sodium iron rechargeable battery and tests were carried out to find the formation of crystal structure. Synthesis of Na x NiO 2 nonporous active material were made using solid state reactions at 700 ° C and the material development was studied by XRD characterizing technique. The developed Na x NiO 2 was used as the active cathode material in a rechargeable half cell. The characterization confirmed the crystal structure of NaNiO 2 to be monoclinic, and also its surface morphology. Electron transition status test revealed the specific energy band gap to be 5.16 eV. Charge transfer resistance of the cathode material obtained was 13,121 Ω. The further investigations on charge discharge revealed the maximum efficient charging rate per gram as 7.5 mA for 0.12 hours and maximum rate of discharge for maximum charge retention as 25 mA rate of charge per gram of Na x NiO 2 which was the active material of the rechargeable cell. The charge discharge cyclability was tested for Sodium Nickel Oxide with 0.2 mA constant current for both charging and discharging. A voltage of 2.34 V was observed as the open voltage (no load) at the beginning and the half cell showed more than 180 charge-discharge cycles in performance including a rest time of one minute for each cycle. This confirmed that the battery is able to hold a fairly high reversibility. DOI: http://dx.doi.org/10.4038/sljp.v15i0.8021 Sri Lankan Journal of Physics, Vol. 15 (2014) 19-29","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"29 1","pages":"19"},"PeriodicalIF":0.0,"publicationDate":"2015-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82107531","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}
M. Jayaweera, R.C.L. De Silva, I. Kottegoda, S. Rosa
High performing sensor consisting of SnO 2 /Gn nanocomposite was fabricated using a novel one-step in-situ sonochemical method. The reducing properties of SnCl 2 was used to reduce graphite oxide (GO) so that SnCl 2 could be transformed to SnO 2 on the basal plane of graphene. The combined characterizations including X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transformed Infra-Red spectroscopic data (FTIR) indicated the successful formation of SnO 2 /Gn composites. Current-voltage (I-V) characteristics of the gas sensor showed ideal ohmic behavior having low resistance. To demonstrate the product on sensing application, gas sensors were fabricated using SnO 2 /Gn composites and used in detecting ethanol vapor at room temperature (27°C).The results indicate that the SnO 2 /Gn composite exhibits a considerably high sensing performance of 17.54% response at 150 ppm ethanol vapor, rapid response and reproducibility. Furthermore, the performance of the gas sensor based on SnO 2 /Gn is very stable for a long period of time under normal operating conditions. Therefore, it is suggested that SnO 2 /Gn can be considered as an excellent sensing material which also has a potential for wider range of applications on sensors.
{"title":"Synthesis, characterization and ethanol vapor sensing performance of SnO2/Graphene composite film","authors":"M. Jayaweera, R.C.L. De Silva, I. Kottegoda, S. Rosa","doi":"10.4038/SLJP.V15I0.6345","DOIUrl":"https://doi.org/10.4038/SLJP.V15I0.6345","url":null,"abstract":"High performing sensor consisting of SnO 2 /Gn nanocomposite was fabricated using a novel one-step in-situ sonochemical method. The reducing properties of SnCl 2 was used to reduce graphite oxide (GO) so that SnCl 2 could be transformed to SnO 2 on the basal plane of graphene. The combined characterizations including X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transformed Infra-Red spectroscopic data (FTIR) indicated the successful formation of SnO 2 /Gn composites. Current-voltage (I-V) characteristics of the gas sensor showed ideal ohmic behavior having low resistance. To demonstrate the product on sensing application, gas sensors were fabricated using SnO 2 /Gn composites and used in detecting ethanol vapor at room temperature (27°C).The results indicate that the SnO 2 /Gn composite exhibits a considerably high sensing performance of 17.54% response at 150 ppm ethanol vapor, rapid response and reproducibility. Furthermore, the performance of the gas sensor based on SnO 2 /Gn is very stable for a long period of time under normal operating conditions. Therefore, it is suggested that SnO 2 /Gn can be considered as an excellent sensing material which also has a potential for wider range of applications on sensors.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"65 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2015-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90257776","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}
Non-strange excited baryons are analyzed within the Large QCD framework. The Large approach is used as an effective theory to simultaneously fit the masses and decays with corrections up to . Values of the mixing angles for the and nucleon mass eigenstates are obtained within the simultaneous analysis. The observed effective operator hierarchy is consistent with the previous studies conducted in this sector and improved results are obtained. DOI: http://dx.doi.org/10.4038/sljp.v13i2.5443 Sri Lankan Journal of Physics, Vol. 13 ( 2 ) ( 2012 ) 27 - 38
{"title":"Simultaneous analysis of non-strange negative parity baryon Properties in large Nc QCD","authors":"S. Premaratne, C. Jayalath","doi":"10.4038/SLJP.V13I2.5443","DOIUrl":"https://doi.org/10.4038/SLJP.V13I2.5443","url":null,"abstract":"Non-strange excited baryons are analyzed within the Large QCD framework. The Large approach is used as an effective theory to simultaneously fit the masses and decays with corrections up to . Values of the mixing angles for the and nucleon mass eigenstates are obtained within the simultaneous analysis. The observed effective operator hierarchy is consistent with the previous studies conducted in this sector and improved results are obtained. DOI: http://dx.doi.org/10.4038/sljp.v13i2.5443 Sri Lankan Journal of Physics, Vol. 13 ( 2 ) ( 2012 ) 27 - 38","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"123 1","pages":"27"},"PeriodicalIF":0.0,"publicationDate":"2013-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79475638","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}
Cloud-to-ground lightning discharges in 2D and 3D domains were simulated using a stochastic dielectric breakdown model. The dependency between fractal dimension of the discharge patterns and the power of the local electric field η was critically evaluated. An exponential decrease in fractal dimension was observed as η increases. Fractal dimension of simulated 3D discharge patterns and 2D images of lightning discharges were compared by taking projections of simulated patterns. Discharge patterns similar to actual lightning were obtained when η ≈ 5.2. Influence of ground objects on simulated lightning discharges was also studied by introducing additional boundary conditions to the ground plane. It was observed that pointed structures on the ground have a higher probability of attracting simulated lightning discharges. An extension was introduced to dielectric breakdown model to simulate the development of upward connecting positive leader discharges that occur during the decent of a downward moving negative leader. It was found that the height of the stepped leader tip above the ground (at the time when the upward connecting leader initiation occurs) is dependent on the initial breakdown voltage threshold. The height of the point of interception was found to decrease exponentially as the breakdown threshold is increased. DOI: http://dx.doi.org/10.4038/sljp.v13i2.5433 Sri Lankan Journal of Physics, Vol. 13 ( 2 ) ( 2012 ) 09 - 25
{"title":"Fractal Nature of Simulated Lightning Channels","authors":"M.M.N. Perera, D. Sonnadara","doi":"10.4038/SLJP.V13I2.5433","DOIUrl":"https://doi.org/10.4038/SLJP.V13I2.5433","url":null,"abstract":"Cloud-to-ground lightning discharges in 2D and 3D domains were simulated using a stochastic dielectric breakdown model. The dependency between fractal dimension of the discharge patterns and the power of the local electric field η was critically evaluated. An exponential decrease in fractal dimension was observed as η increases. Fractal dimension of simulated 3D discharge patterns and 2D images of lightning discharges were compared by taking projections of simulated patterns. Discharge patterns similar to actual lightning were obtained when η ≈ 5.2. Influence of ground objects on simulated lightning discharges was also studied by introducing additional boundary conditions to the ground plane. It was observed that pointed structures on the ground have a higher probability of attracting simulated lightning discharges. An extension was introduced to dielectric breakdown model to simulate the development of upward connecting positive leader discharges that occur during the decent of a downward moving negative leader. It was found that the height of the stepped leader tip above the ground (at the time when the upward connecting leader initiation occurs) is dependent on the initial breakdown voltage threshold. The height of the point of interception was found to decrease exponentially as the breakdown threshold is increased. DOI: http://dx.doi.org/10.4038/sljp.v13i2.5433 Sri Lankan Journal of Physics, Vol. 13 ( 2 ) ( 2012 ) 09 - 25","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"29 1","pages":"9"},"PeriodicalIF":0.0,"publicationDate":"2013-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82297263","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}
A theoretical model of thundercloud charge separation is presented. The model assume that moisture in the updraft moving as a stream with uniform velocity condenses into particles of graupel in reaching cooler regions of the atmosphere. Falling graupels acquire a negative charge by shedding the inductive positive charge which is carried away by the updraft. Charged graupels moves downward subjected to gravity, force due to the collective electric field and air resistance. Non-linear equations governing the dynamics of the system demonstrate existence of a stable equilibrium electric field of the order of magnitude needed for dielectric breakdown of air. Model also shows that thundercloud electric field could undergo pulsations at infrasonic frequencies and synchronously emit acoustic waves at the same frequency. Preferential positive inductive charging of graupel is explained as a consequence of the proton conductivity of ice. DOI: http://dx.doi.org/10.4038/sljp.v13i2.5432 Sri Lankan Journal of Physics, Vol. 13(2) (2012) 01-07
{"title":"A model for Thundercloud Charge Separation","authors":"K. Tennakone, P. Hewageegana","doi":"10.4038/SLJP.V13I2.5432","DOIUrl":"https://doi.org/10.4038/SLJP.V13I2.5432","url":null,"abstract":"A theoretical model of thundercloud charge separation is presented. The model assume that moisture in the updraft moving as a stream with uniform velocity condenses into particles of graupel in reaching cooler regions of the atmosphere. Falling graupels acquire a negative charge by shedding the inductive positive charge which is carried away by the updraft. Charged graupels moves downward subjected to gravity, force due to the collective electric field and air resistance. Non-linear equations governing the dynamics of the system demonstrate existence of a stable equilibrium electric field of the order of magnitude needed for dielectric breakdown of air. Model also shows that thundercloud electric field could undergo pulsations at infrasonic frequencies and synchronously emit acoustic waves at the same frequency. Preferential positive inductive charging of graupel is explained as a consequence of the proton conductivity of ice. DOI: http://dx.doi.org/10.4038/sljp.v13i2.5432 Sri Lankan Journal of Physics, Vol. 13(2) (2012) 01-07","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"22 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2013-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74377317","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}
We develop a method for calculating the polarizability of a spherical nano particle by taking in to account the temporal and spatial dispersion where dispersion due to the Landau damping. To describe these phenomena, we developed analytical theory based on local random-phase approximation. Our theory is very general in the sense that it can be applied to any material which can be characterized by a bulk dielectric function of the form e(κ,ω) . The theory is applied to calculate the polarizabilities of dielectric and metallic nanospheres. Keywords: metallic nanosphere; polarizability; random-phase approximation DOI: http://dx.doi.org/10.4038/sljp.v13i1.4211 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 41-47
{"title":"Polarizability of a metallic nanosphere: Local random-phase approximation (LRPA)","authors":"P. Hewageegana","doi":"10.4038/SLJP.V13I1.4211","DOIUrl":"https://doi.org/10.4038/SLJP.V13I1.4211","url":null,"abstract":"We develop a method for calculating the polarizability of a spherical nano particle by taking in to account the temporal and spatial dispersion where dispersion due to the Landau damping. To describe these phenomena, we developed analytical theory based on local random-phase approximation. Our theory is very general in the sense that it can be applied to any material which can be characterized by a bulk dielectric function of the form e(κ,ω) . The theory is applied to calculate the polarizabilities of dielectric and metallic nanospheres. Keywords: metallic nanosphere; polarizability; random-phase approximation DOI: http://dx.doi.org/10.4038/sljp.v13i1.4211 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 41-47","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"47 1","pages":"41"},"PeriodicalIF":0.0,"publicationDate":"2012-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80796516","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}
We know that the electric charge of an isolated system is relativistically invariant. We have studied the transformation of surface charge density in Special, Most general, Mixed number Lorentz transformation. As the formula of length contraction is not the same in these types of Lorentz transformation, the transformation equation of surface charge density will be different in the above mentioned transformations. Keywords: Special Lorentz Transformation; Surface charge density DOI: http://dx.doi.org/10.4038/sljp.v13i1.3546 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 17-25
{"title":"Transformation of Surface Charge Density in Mixed Number Lorentz Transformation","authors":"S. Rafiq, M. S. Alam","doi":"10.4038/SLJP.V13I1.3546","DOIUrl":"https://doi.org/10.4038/SLJP.V13I1.3546","url":null,"abstract":"We know that the electric charge of an isolated system is relativistically invariant. We have studied the transformation of surface charge density in Special, Most general, Mixed number Lorentz transformation. As the formula of length contraction is not the same in these types of Lorentz transformation, the transformation equation of surface charge density will be different in the above mentioned transformations. Keywords: Special Lorentz Transformation; Surface charge density DOI: http://dx.doi.org/10.4038/sljp.v13i1.3546 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 17-25","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"46 1","pages":"17"},"PeriodicalIF":0.0,"publicationDate":"2012-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75550355","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}
Gross alpha and gross beta activities were determined for twenty tap water samples collected from different locations in Dhaka city. The instrumentations used to count the gross alpha and gross beta activities were ZnS scintillation detector and gas proportional counter, respectively. Concentrations ranging from 1.88 ± 0.03 mBq / l to 8.16 ± 0.03 mBq / l with an average 3.76 ± 1.50 mBq / l and from 29.305 ± 0.06 mBq/ l to 115.74 ± 0.16 mBq / l with an average 60.41 ± 23.57 mBq /l were observed for the gross alpha and gross beta activities, respectively. The results showed that the natural activities of alpha and beta emitting radionuclides in tap water samples did not exceed WHO recommended levels and were comparable with the data available in other parts of the world. It suggests that the radioactivity in tap water for the people residing in Dhaka city is not yet a problem. To ensure the safe level of radioactivity in drinking water, however, periodic monitoring of water quality for compliance is necessary. DOI: http://dx.doi.org/10.4038/sljp.v13i1.3917 Keywords: Gross Alpha; Gross beta; Tap water; ZnS Scintillation Counter and Gas Proportional Counter Sri Lankan Journal of Physics, Vol. 13(1) (2012) 01-08
{"title":"Gross Alpha and Gross Beta Activities of Tap Water Samples from Different Locations of Dhaka City","authors":"M. Ferdous, M. Rahman, A. Begum","doi":"10.4038/SLJP.V13I1.3917","DOIUrl":"https://doi.org/10.4038/SLJP.V13I1.3917","url":null,"abstract":"Gross alpha and gross beta activities were determined for twenty tap water samples collected from different locations in Dhaka city. The instrumentations used to count the gross alpha and gross beta activities were ZnS scintillation detector and gas proportional counter, respectively. Concentrations ranging from 1.88 ± 0.03 mBq / l to 8.16 ± 0.03 mBq / l with an average 3.76 ± 1.50 mBq / l and from 29.305 ± 0.06 mBq/ l to 115.74 ± 0.16 mBq / l with an average 60.41 ± 23.57 mBq /l were observed for the gross alpha and gross beta activities, respectively. The results showed that the natural activities of alpha and beta emitting radionuclides in tap water samples did not exceed WHO recommended levels and were comparable with the data available in other parts of the world. It suggests that the radioactivity in tap water for the people residing in Dhaka city is not yet a problem. To ensure the safe level of radioactivity in drinking water, however, periodic monitoring of water quality for compliance is necessary. DOI: http://dx.doi.org/10.4038/sljp.v13i1.3917 Keywords: Gross Alpha; Gross beta; Tap water; ZnS Scintillation Counter and Gas Proportional Counter Sri Lankan Journal of Physics, Vol. 13(1) (2012) 01-08","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"24 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2012-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86575555","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}
We solve approximately the bound state solutions of the Klein - Gordon equation for deformed Hulthen potential with unequal scalar and vector potential for arbitrary l -state. We obtain explicitly the energy eigenvalues and the corresponding wave function expressed in terms of the Jacobi polynomials. We also discuss the energy eigenvalues of our result for three cases with equal and unequal scalar and vector potentials. Keywords: Klein-Gordon equation; Hulthen potential; bound state DOI: http://dx.doi.org/10.4038/sljp.v13i1.3780 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 27-40
{"title":"Bound state solutions of the Klein - Gordon equation for deformed Hulthen potential with position dependent mass","authors":"A. Antia, A. Ikot, E. Ituen, I. Akpan","doi":"10.4038/SLJP.V13I1.3780","DOIUrl":"https://doi.org/10.4038/SLJP.V13I1.3780","url":null,"abstract":"We solve approximately the bound state solutions of the Klein - Gordon equation for deformed Hulthen potential with unequal scalar and vector potential for arbitrary l -state. We obtain explicitly the energy eigenvalues and the corresponding wave function expressed in terms of the Jacobi polynomials. We also discuss the energy eigenvalues of our result for three cases with equal and unequal scalar and vector potentials. Keywords: Klein-Gordon equation; Hulthen potential; bound state DOI: http://dx.doi.org/10.4038/sljp.v13i1.3780 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 27-40","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"40 1","pages":"27"},"PeriodicalIF":0.0,"publicationDate":"2012-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81364311","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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