Lithium rechargeable cells based on liquid electrolytes have been used for numerous applications due to their high performance. At present, it has been identified the possible hazardous effects of those cells. As an alternative, much research is focused on non-lithium rechargeable cells based on Gel Polymer Electrolytes (GPEs). Basically, a GPE is consisted of a salt and solvent mixture entrapped inside a polymer network. However, these solvents are toxic and flammable. This imposes a limitation for the safety of GPEs. This paper, reported about a Zn rechargeable cell having a GPE based on an ionic liquid which eliminates the need of solvents. The polymer used was Poly-Vinylidene Fluoride co Hexa FluoroPropylene (PVdF-co-HFP). As the salt, Zinc Tri-Fluoromethanesulfonate (Zn(CF3SO3)2 – ZnTF) was used and 1 Butyl 3 Methyl Immidazolium Tri-Fluoromethanesulfonate (1B3MITF) was used as the Ionic Liquid (IL). It was observed that there is an optimum salt concentration that results the highest conductivity in IL. A Zn rechargeable cell was fabricated using the optimized composition of the GPE. It was observed that the cell is suitable for low power requirements.
{"title":"Zn rechargeable cell with a gel polymer electrolyte based on an ionic liquid","authors":"K. W. Prasadini, K. Perera, K. Vidanapathirana","doi":"10.4038/SLJP.V18I0.8047","DOIUrl":"https://doi.org/10.4038/SLJP.V18I0.8047","url":null,"abstract":"Lithium rechargeable cells based on liquid electrolytes have been used for numerous applications due to their high performance. At present, it has been identified the possible hazardous effects of those cells. As an alternative, much research is focused on non-lithium rechargeable cells based on Gel Polymer Electrolytes (GPEs). Basically, a GPE is consisted of a salt and solvent mixture entrapped inside a polymer network. However, these solvents are toxic and flammable. This imposes a limitation for the safety of GPEs. This paper, reported about a Zn rechargeable cell having a GPE based on an ionic liquid which eliminates the need of solvents. The polymer used was Poly-Vinylidene Fluoride co Hexa FluoroPropylene (PVdF-co-HFP). As the salt, Zinc Tri-Fluoromethanesulfonate (Zn(CF3SO3)2 – ZnTF) was used and 1 Butyl 3 Methyl Immidazolium Tri-Fluoromethanesulfonate (1B3MITF) was used as the Ionic Liquid (IL). It was observed that there is an optimum salt concentration that results the highest conductivity in IL. A Zn rechargeable cell was fabricated using the optimized composition of the GPE. It was observed that the cell is suitable for low power requirements.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"38 1","pages":"35"},"PeriodicalIF":0.0,"publicationDate":"2017-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73181478","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. R. Obasuyi, A. B. Alabi, Emmanuel Dami Kajewole, O. Robert, F. Abejide, T. Adeleke, T. Akomolafe
Zinc Oxide nanoparticles (ZnO) have been successfully synthesized by a chemical method at a low temperature of 60°C and dried at 80°C. The matching of the observed 2 q value with the JCPDS value of the XRD pattern showed that ZnO was synthesized. The pattern obtained showed high peaks as an indication of crystallinity at low temperature without annealing. The average grain size of the crystal obtained using Debye scherrer formular is 18.6 nm. The crystal structure lattice system is hexagonal wurzite structure. The SEM images obtained showed that the material is made up of agglomerated grains resulting in nanostructured islands. The direct optical band gap was obtained using Tauc’s relationship to be 2.4 eV. A bioenzymevoltaic cell was developed in form of a Dye Sensitized Solar Cell but with a photosynthetic material: Chromolaena Odorata acting as both the dye and the electrolyte. The short circuit current of 1.5 mA and open circuit voltage of 170 mV were obtained for the continuous and residual energy on the system. We found that the device exhibited a bio-capacitive effect, as the photosynthetic material generates electron and the energy is being stored in the system as much as 39 mA with a corresponding voltage of 196 mV.
{"title":"Capacitive and Bioenzymevoltaic Characteristics of Photosynthetic Chromolena Odorata – Nanostructured Zinc Oxide System","authors":"A. R. Obasuyi, A. B. Alabi, Emmanuel Dami Kajewole, O. Robert, F. Abejide, T. Adeleke, T. Akomolafe","doi":"10.4038/SLJP.V18I0.8041","DOIUrl":"https://doi.org/10.4038/SLJP.V18I0.8041","url":null,"abstract":"Zinc Oxide nanoparticles (ZnO) have been successfully synthesized by a chemical method at a low temperature of 60°C and dried at 80°C. The matching of the observed 2 q value with the JCPDS value of the XRD pattern showed that ZnO was synthesized. The pattern obtained showed high peaks as an indication of crystallinity at low temperature without annealing. The average grain size of the crystal obtained using Debye scherrer formular is 18.6 nm. The crystal structure lattice system is hexagonal wurzite structure. The SEM images obtained showed that the material is made up of agglomerated grains resulting in nanostructured islands. The direct optical band gap was obtained using Tauc’s relationship to be 2.4 eV. A bioenzymevoltaic cell was developed in form of a Dye Sensitized Solar Cell but with a photosynthetic material: Chromolaena Odorata acting as both the dye and the electrolyte. The short circuit current of 1.5 mA and open circuit voltage of 170 mV were obtained for the continuous and residual energy on the system. We found that the device exhibited a bio-capacitive effect, as the photosynthetic material generates electron and the energy is being stored in the system as much as 39 mA with a corresponding voltage of 196 mV.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"2 1","pages":"17"},"PeriodicalIF":0.0,"publicationDate":"2017-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86513635","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}
Protons, electrons, alpha particles, and heavier ions in the solar wind are emitted from the Sun’s coronal plasma. Energetic phenomenon such as a Coronal Mass Ejection (CME) releases high energy as electromagnetic radiation in the form of solar X-rays and γ-ray bursts. This intense radiation is responsible for ionizing the constituent particles of the various layers of Earth’s ionosphere. In the presence of perturbations of the thermospheric region produced by CME, different characteristic parameters are theoretically investigated through momentum and energy balance equations, equation of continuity and equation of state. Dispersive nature of the medium is investigated and altitude variations of resulting electric field are carried out. In the computation processes, data of the latest International Reference Ionosphere (IRI) models are used. The results obtained are to be compared and supported by the experimental findings from other researchers to understand the nature of the medium in detail.
{"title":"Impact of Coronal Mass Ejection on different characteristic parameters of lower thermospheric region","authors":"S. Paul, S. S. De","doi":"10.4038/SLJP.V18I0.8035","DOIUrl":"https://doi.org/10.4038/SLJP.V18I0.8035","url":null,"abstract":"Protons, electrons, alpha particles, and heavier ions in the solar wind are emitted from the Sun’s coronal plasma. Energetic phenomenon such as a Coronal Mass Ejection (CME) releases high energy as electromagnetic radiation in the form of solar X-rays and γ-ray bursts. This intense radiation is responsible for ionizing the constituent particles of the various layers of Earth’s ionosphere. In the presence of perturbations of the thermospheric region produced by CME, different characteristic parameters are theoretically investigated through momentum and energy balance equations, equation of continuity and equation of state. Dispersive nature of the medium is investigated and altitude variations of resulting electric field are carried out. In the computation processes, data of the latest International Reference Ionosphere (IRI) models are used. The results obtained are to be compared and supported by the experimental findings from other researchers to understand the nature of the medium in detail.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"110 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2017-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80685289","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}
The Frost-Musulin Diatomic molecular potential has been investigated under spin and pseudospin symmetries of the Dirac equation in a comparative study. By using a siutable approximation scheme, we have presented the energy eigenvalues for both the spin symmetry and pseudospin symmetry and the corresponding upper and lower spinor component of the wave functions in a close form. We have obtained the non-relativistic limit and compared our numerical eigenvalues with the one previousely obtained. Finally, we calculated thermodynamic properties of a particle under the Frost-Musulin diatomic potential.
{"title":"Dirac particles in the field of Frost-Musulin diatomic potential and the thermodynamic properties via parametric Nikiforov-Uvarov method","authors":"C. Onate, M. Onyeaju","doi":"10.4038/SLJP.V17I0.8027","DOIUrl":"https://doi.org/10.4038/SLJP.V17I0.8027","url":null,"abstract":"The Frost-Musulin Diatomic molecular potential has been investigated under spin and pseudospin symmetries of the Dirac equation in a comparative study. By using a siutable approximation scheme, we have presented the energy eigenvalues for both the spin symmetry and pseudospin symmetry and the corresponding upper and lower spinor component of the wave functions in a close form. We have obtained the non-relativistic limit and compared our numerical eigenvalues with the one previousely obtained. Finally, we calculated thermodynamic properties of a particle under the Frost-Musulin diatomic potential.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"1 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2017-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73991736","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}
There is a great attention towards fulfilling energy requirement via renewable energy sources. Solar energy is one of the uprising renewable energy sources for the planet earth. Dye sensitized solar cells (DSSCs) have been identified as a promising technology to harvest solar energy and to convert that to electricity. In this study, it was attempted to optimize the composition of a gel polymer electrolyte consisting with polyvinylidene fluoride (PVdF), ethylene carbonate (EC), propylene carbonate (PC), tetrahexylammonium iodide (Hex 4 NI) and iodide (I 2 ) to be utilized for DSSC application. The composition was fine tuned to get the highest conductivity by varying the salt concentration. The composition, 100 PVdF / 400 EC / 400 PC / 150 Hex 4 NI / 7.3 I 2 exhibited the highest conductivity of 3.43 x 10 -3 Scm -1 at room temperature. Sample was purely an anionic conductor. DSSCs were fabricated in the configuration, FTO / TiO 2 / Dye / GPE / Pt / FTO. The open circuit voltage and short circuit current density were 799 mV and 1.06 mA respectively. The calculated fill factor was 0.62 and the efficiency was 2.08%.
人们非常重视通过可再生能源来满足能源需求。太阳能是地球上新兴的可再生能源之一。染料敏化太阳能电池(DSSCs)已被确定为一种很有前途的技术来收集太阳能并将其转化为电能。在本研究中，试图优化由聚偏氟乙烯(PVdF)、碳酸乙烯(EC)、碳酸丙烯(PC)、四己基碘化铵(hex4 NI)和碘化物(i2)组成的凝胶聚合物电解质的组成，以用于DSSC的应用。通过改变盐的浓度，对其组成进行微调以获得最高的电导率。该组合物为100 PVdF / 400 EC / 400 PC / 150 Hex 4 NI / 7.3 I 2，在室温下电导率最高，为3.43 x 10 -3 Scm -1。样品是纯阴离子导体。制备了FTO / tio2 / Dye / GPE / Pt / FTO结构的DSSCs。开路电压为799 mV，短路电流密度为1.06 mA。计算得到的填充系数为0.62，效率为2.08%。
{"title":"Polyvinylidene fluoride based gel polymer electrolyte to be used in solar energy to electrical energy conversion","authors":"K. Perera, K. Vidanapathirana","doi":"10.4038/SLJP.V17I0.8037","DOIUrl":"https://doi.org/10.4038/SLJP.V17I0.8037","url":null,"abstract":"There is a great attention towards fulfilling energy requirement via renewable energy sources. Solar energy is one of the uprising renewable energy sources for the planet earth. Dye sensitized solar cells (DSSCs) have been identified as a promising technology to harvest solar energy and to convert that to electricity. In this study, it was attempted to optimize the composition of a gel polymer electrolyte consisting with polyvinylidene fluoride (PVdF), ethylene carbonate (EC), propylene carbonate (PC), tetrahexylammonium iodide (Hex 4 NI) and iodide (I 2 ) to be utilized for DSSC application. The composition was fine tuned to get the highest conductivity by varying the salt concentration. The composition, 100 PVdF / 400 EC / 400 PC / 150 Hex 4 NI / 7.3 I 2 exhibited the highest conductivity of 3.43 x 10 -3 Scm -1 at room temperature. Sample was purely an anionic conductor. DSSCs were fabricated in the configuration, FTO / TiO 2 / Dye / GPE / Pt / FTO. The open circuit voltage and short circuit current density were 799 mV and 1.06 mA respectively. The calculated fill factor was 0.62 and the efficiency was 2.08%.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"214 1","pages":"29"},"PeriodicalIF":0.0,"publicationDate":"2017-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73114530","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}
With the use of the modified pseudospin lattice coupled-mode (PLCM) model by adding third-order and fourth-order phonon anharmonic interactions terms and the statistical Green’s function technique a phenomenological explanation of phase transition of the lead monohydrogen arsenate (PbHAsO 4 ) crystal has been given. Expressions for shift, width, dielectric constant, loss tangent and modified ferroelectric soft mode frequency have been derived theoretically. By fitting model values of various quantities obtained from literature in these derived expressions, their temperature dependence has been evaluated numerically. Present theoretically results agree well with the experimental results of others.
{"title":"Temperature dependent structural Phase transition in Lead Mono Hydrogen Aresenate crystal","authors":"A. Rawat, A. Rawat, T. C. Upadhyay","doi":"10.4038/SLJP.V17I0.8028","DOIUrl":"https://doi.org/10.4038/SLJP.V17I0.8028","url":null,"abstract":"With the use of the modified pseudospin lattice coupled-mode (PLCM) model by adding third-order and fourth-order phonon anharmonic interactions terms and the statistical Green’s function technique a phenomenological explanation of phase transition of the lead monohydrogen arsenate (PbHAsO 4 ) crystal has been given. Expressions for shift, width, dielectric constant, loss tangent and modified ferroelectric soft mode frequency have been derived theoretically. By fitting model values of various quantities obtained from literature in these derived expressions, their temperature dependence has been evaluated numerically. Present theoretically results agree well with the experimental results of others.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"29 1","pages":"19"},"PeriodicalIF":0.0,"publicationDate":"2017-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76647448","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}
C. Bandaranayake, W.A.D.S.S. Weerasinghe, K. Vidanapathirana, K. Perera
This work describes the performance of a gel polymer electrolyte (GPE) based redox capacitor using the cyclic voltammetry technique.GPE was prepared with 22.5 wt% polyacrylonitrile (PAN), (1:1weight ratio) ethylene carbonate (EC) and propylene carbonate (PC) having a salt concentration of 1.0 M sodium iodide (NaI). Dependence of ionic conductivity of GPE on temperature was investigated using ac impedance spectroscopy. Two polypyrrole (PPy) electrodes were used as the electrodes of the redox capacitor. The performance of the device was evaluated by cyclic voltammetry. The redox-capacitors were cycled at different scan rates to determine the scan rate at which the maximum capacitance is obtained. After tracking that scan rate, continuous cycling was carried out at that scan rate to investigate the deterioration of capacitance upon cycling. The room temperature conductivity (σ) of the GPE was 4.29 × 10 -3 S cm -1 . The conductivity variation with temperature followed the Arrhenius behavior. From the scan rates selected for the study, the maximum capacity could be obtained at the scan rate of 30 mV s -1 . The average specific capacity of the redox capacitor was 26.70 Fg -1 .
本文描述了一种基于凝胶聚合物电解质(GPE)的氧化还原电容器的循环伏安法性能。以22.5 wt%的聚丙烯腈(PAN)、1:1质量比的碳酸乙烯(EC)和碳酸丙烯(PC)为原料，盐浓度为1.0 M的碘化钠(NaI)制备GPE。用交流阻抗谱法研究了GPE离子电导率随温度的变化规律。采用两个聚吡咯(PPy)电极作为氧化还原电容器电极。用循环伏安法评价了该装置的性能。在不同的扫描速率下循环氧化还原电容器，以确定获得最大电容的扫描速率。跟踪该扫描速率后，在该扫描速率下进行连续循环，以研究循环时电容的恶化情况。GPE的室温电导率σ为4.29 × 10 -3 S cm -1。电导率随温度的变化遵循Arrhenius行为。从所选择的扫描速率来看，在扫描速率为30 mV s -1时可获得最大容量。氧化还原电容器的平均比容量为26.70 Fg -1。
{"title":"A Cyclic Voltammetry study of a gel polymer electrolyte based redox-capacitor","authors":"C. Bandaranayake, W.A.D.S.S. Weerasinghe, K. Vidanapathirana, K. Perera","doi":"10.4038/SLJP.V16I1.8026","DOIUrl":"https://doi.org/10.4038/SLJP.V16I1.8026","url":null,"abstract":"This work describes the performance of a gel polymer electrolyte (GPE) based redox capacitor using the cyclic voltammetry technique.GPE was prepared with 22.5 wt% polyacrylonitrile (PAN), (1:1weight ratio) ethylene carbonate (EC) and propylene carbonate (PC) having a salt concentration of 1.0 M sodium iodide (NaI). Dependence of ionic conductivity of GPE on temperature was investigated using ac impedance spectroscopy. Two polypyrrole (PPy) electrodes were used as the electrodes of the redox capacitor. The performance of the device was evaluated by cyclic voltammetry. The redox-capacitors were cycled at different scan rates to determine the scan rate at which the maximum capacitance is obtained. After tracking that scan rate, continuous cycling was carried out at that scan rate to investigate the deterioration of capacitance upon cycling. The room temperature conductivity (σ) of the GPE was 4.29 × 10 -3 S cm -1 . The conductivity variation with temperature followed the Arrhenius behavior. From the scan rates selected for the study, the maximum capacity could be obtained at the scan rate of 30 mV s -1 . The average specific capacity of the redox capacitor was 26.70 Fg -1 .","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"88 1","pages":"19"},"PeriodicalIF":0.0,"publicationDate":"2016-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79382366","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}
The measurement of atmospheric aerosol number concentration has been carried out at a remotely polluted site (Roorkee, 29o 52’ N, 77o 53’ E, 275 m above mean sea level) in northern India during pre monsoon period of 2009 at a height of 9 m above ground level. The aerosol number concentration having different sizes (0.3-0.5, 0.5-1.0, 1.0-2.0 and 2.0-5.0 μm) in pre monsoon summer season 0f 2009 has been analyzed, and the daily variation of aerosol number concentration has been related to selected meteorological parameters like as relative humidity, temperature, rainfall and wind speed. The measurements were made with an optical partical counter. The aerosol number concentration for upper size ranges (1.0-2.0 and 2.0-5.0 μm) is maximum in June and minimum in July. The aerosol number concentration in small size ranges (0.3-0.5 and 0.5-1.0 μm) decreases monotonically till the end of July.
{"title":"Optical particle sensor based measurement and analysis of atmospheric aerosol number concentration of various sizes over a tropical region of Northern India","authors":"Adarsh Kumar","doi":"10.4038/SLJP.V16I1.7890","DOIUrl":"https://doi.org/10.4038/SLJP.V16I1.7890","url":null,"abstract":"The measurement of atmospheric aerosol number concentration has been carried out at a remotely polluted site (Roorkee, 29o 52’ N, 77o 53’ E, 275 m above mean sea level) in northern India during pre monsoon period of 2009 at a height of 9 m above ground level. The aerosol number concentration having different sizes (0.3-0.5, 0.5-1.0, 1.0-2.0 and 2.0-5.0 μm) in pre monsoon summer season 0f 2009 has been analyzed, and the daily variation of aerosol number concentration has been related to selected meteorological parameters like as relative humidity, temperature, rainfall and wind speed. The measurements were made with an optical partical counter. The aerosol number concentration for upper size ranges (1.0-2.0 and 2.0-5.0 μm) is maximum in June and minimum in July. The aerosol number concentration in small size ranges (0.3-0.5 and 0.5-1.0 μm) decreases monotonically till the end of July.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"23 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2016-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79873495","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}
Mesoscale simulation of a flood producing rainstorm of 21 June 2004 over Rangamati, Bangladesh has been carried out using the MM5 Model. The model performance was evaluated by examining the different predicted and model derived parameters. The MM5 model suggests that the rainstorm over Rangamati was resulted by the large scale weather circulation associated with active conditions of southwest summer monsoon over the head Bay of Bengal which generated favourable conditions for developing the severe mesoscale convections. The strong confluence of southwesterly low level flow transporting large amount of moisture (which vertically extended up to 350 hPa) from the Bay of Bengal towards southeast Bangladesh and its neighbourhoods appears to be one of the striking features. An elongated vorticity maximum of the order of 30-40×10 -5 s -1 was observed across the Rangamati. A well-defined area of low level convergence (-25×10 -5 s -1 ) is associated with strong divergence (25×10 -5 s -1 ) in the high level (200 hPa) has provided favourable conditions for strong convection. The model simulated realistic pattern of rainfall over Rangamati as compared with TRMM observations. Considering the quantitative comparison of the domain average rainfall with TRMM observations, it is found that the model over predicts by 12% as compared with TRMM observed rainfall.
利用MM5模式对2004年6月21日发生在孟加拉国Rangamati的一次致洪暴雨进行了中尺度模拟。通过检验不同的预测参数和模型推导参数来评价模型的性能。MM5模式提示Rangamati暴雨是由孟加拉湾上游西南夏季风活跃的大尺度天气环流引起的，为强中尺度对流的发展创造了有利条件。从孟加拉湾向孟加拉国东南部及其邻近地区输送大量水汽(垂直延伸至350 hPa)的西南低空气流的强合流似乎是显著特征之一。在Rangamati上空观测到一个伸长的涡度最大值为30-40×10 -5 s -1数量级。低层辐合区(-25×10 -5 s -1)与高层(200 hPa)强辐散区(25×10 -5 s -1)相关，为强对流提供了有利条件。与TRMM观测值相比，该模式模拟了Rangamati的真实降雨模式。将区域平均降雨量与TRMM观测值进行定量比较，发现该模式的预测精度比TRMM观测值高出12%。
{"title":"Mesoscale simulation of a flood producing rainstorm over Rangamati, Bangladesh using MM5 model","authors":"M. Ahasan, M. Chowdhury, D. Quadir","doi":"10.4038/SLJP.V15I0.6824","DOIUrl":"https://doi.org/10.4038/SLJP.V15I0.6824","url":null,"abstract":"Mesoscale simulation of a flood producing rainstorm of 21 June 2004 over Rangamati, Bangladesh has been carried out using the MM5 Model. The model performance was evaluated by examining the different predicted and model derived parameters. The MM5 model suggests that the rainstorm over Rangamati was resulted by the large scale weather circulation associated with active conditions of southwest summer monsoon over the head Bay of Bengal which generated favourable conditions for developing the severe mesoscale convections. The strong confluence of southwesterly low level flow transporting large amount of moisture (which vertically extended up to 350 hPa) from the Bay of Bengal towards southeast Bangladesh and its neighbourhoods appears to be one of the striking features. An elongated vorticity maximum of the order of 30-40×10 -5 s -1 was observed across the Rangamati. A well-defined area of low level convergence (-25×10 -5 s -1 ) is associated with strong divergence (25×10 -5 s -1 ) in the high level (200 hPa) has provided favourable conditions for strong convection. The model simulated realistic pattern of rainfall over Rangamati as compared with TRMM observations. Considering the quantitative comparison of the domain average rainfall with TRMM observations, it is found that the model over predicts by 12% as compared with TRMM observed rainfall.","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"27 1","pages":"31"},"PeriodicalIF":0.0,"publicationDate":"2015-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87741501","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}
Y. Jayathilake, K. Perera, K. Vidanapathirana, L. Bandara
Gel polymer electrolytes are known to be very suitable for many electrochemical devices. They Gel polymer electrolytes are known to be very suitable for many electrochemical devices. They have been extensively studied for lithium based electrochemical cells. But, due to several drawbacks of lithium based cells such as safety issues, handling problems and toxicity, it is the time to develop non Li based cells. In this study, ionic conductivity of a gel polymer electrolyte (GPE) based on polymethylmethacrylate, ethylene carbonate, propylene carbonate and tetrapropylammonium iodide and its performance in an Mg / C: I 2 cell was investigated. GPE was prepared by varying salt concentration using hot pressed method and the composition, 20 PMMA / 30 EC / 30 PC / 40 Pr 4 N + I showed the highest conductivity of 5.02 x 10 -3 Scm -1 at 28 ° C. The cell in the form Mg / GPE / C+I 2 showed an average open circuit voltage of 1.9 V. The average short circuit current was 3.3 mA. It was possible to observe a good stability by the self discharge characteristics of the cell. DOI: http://dx.doi.org/10.4038/sljp.v15i0.6638 Sri Lankan Journal of Physics, Vol. 15 (2014) 11-17
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