Altitude variation of fair weather atmospheric electrical parameters such as atmospheric conductivity, air-earth current density, electric field, and atmospheric potential have been analyzed over 210 different places of Sri Lanka when the fair weather conditions were being existed. Atmospheric electrical conductivity and current density on the surface of ground of hilly (high altitude) areas have been found to be increased with height from sea level, while constant value is observed for the electric field in all instants and atmospheric potential on surface of ground of hilly (high altitude) areas decreases with height from sea level (altitude) in Sri Lankan orography (This is not confused with the vertical upward variation at a particular place). Best fit regression lines along with the statistical parameters between the atmospheric electrical parameters and different heights from sea level have been utilized for the different orography of Sri Lanka when clean and clear atmosphere are being existed to verify the assumption of fair weather conditions. Keywords: Atmospheric conductivity; Electric field; Orography; Cosmic rays. DOI: http://dx.doi.org/10.4038/sljp.v13i1.2104 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 09-16
{"title":"Orographic features of global atmospheric fair weather electrical parameters over different places of Sri Lanka","authors":"Deepti Saxena, R. Yadav, Adarsh Kumar","doi":"10.4038/SLJP.V13I1.2104","DOIUrl":"https://doi.org/10.4038/SLJP.V13I1.2104","url":null,"abstract":"Altitude variation of fair weather atmospheric electrical parameters such as atmospheric conductivity, air-earth current density, electric field, and atmospheric potential have been analyzed over 210 different places of Sri Lanka when the fair weather conditions were being existed. Atmospheric electrical conductivity and current density on the surface of ground of hilly (high altitude) areas have been found to be increased with height from sea level, while constant value is observed for the electric field in all instants and atmospheric potential on surface of ground of hilly (high altitude) areas decreases with height from sea level (altitude) in Sri Lankan orography (This is not confused with the vertical upward variation at a particular place). Best fit regression lines along with the statistical parameters between the atmospheric electrical parameters and different heights from sea level have been utilized for the different orography of Sri Lanka when clean and clear atmosphere are being existed to verify the assumption of fair weather conditions. Keywords: Atmospheric conductivity; Electric field; Orography; Cosmic rays. DOI: http://dx.doi.org/10.4038/sljp.v13i1.2104 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 09-16","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"24 1","pages":"9"},"PeriodicalIF":0.0,"publicationDate":"2012-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90471785","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}
N. Jayatissa, R. Attalage, P. Hewageegana, P. Perera, M. A. Punyasena
A small-scale experimental salinity-gradient solar pond, which will be utilized for the research and development in harnessing solar energy for desalination of seawater and generation of electricity, has been constructed. The pond has effective length, width and depth of 3.0 m, 2.0 m and 2.0 m, respectively, covering a volume capacity of 12.0 m 3 . Thermal insulation plays a major role for the successful operation of a salinity-gradient solar pond, especially when the dimensions of the pond are relatively small. The construction details of the solar pond, with particular attention to the methodologies adapted for the thermal insulation, are reported in the present work. The expected total rate of heat loss due to conduction through the thermally insulated boundary walls, assuming a bottom temperature of 90oC, has been calculated and found to be 106.3 W. Contribution from the bottom convective zone itself to this total rate of heat loss is 69 W, which corresponds to 65% of the total value. Based on this rate, the estimated temperature drop during the period with no solar radiation present in a typical day is only 0.3oC. With such a small temperature drop, it is possible to extract the thermal energy stored in the bottom convective zone during the day time, continuously, while maintaining the stability of the solar pond. Keywords: Salinity-gradient solar pond; thermal insulation; desalination DOI: http://dx.doi.org/10.4038/sljp.v13i1.4212 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 49-57
{"title":"Optimization of thermal insulation of a small-scale experimental solar pond","authors":"N. Jayatissa, R. Attalage, P. Hewageegana, P. Perera, M. A. Punyasena","doi":"10.4038/SLJP.V13I1.4212","DOIUrl":"https://doi.org/10.4038/SLJP.V13I1.4212","url":null,"abstract":"A small-scale experimental salinity-gradient solar pond, which will be utilized for the research and development in harnessing solar energy for desalination of seawater and generation of electricity, has been constructed. The pond has effective length, width and depth of 3.0 m, 2.0 m and 2.0 m, respectively, covering a volume capacity of 12.0 m 3 . Thermal insulation plays a major role for the successful operation of a salinity-gradient solar pond, especially when the dimensions of the pond are relatively small. The construction details of the solar pond, with particular attention to the methodologies adapted for the thermal insulation, are reported in the present work. The expected total rate of heat loss due to conduction through the thermally insulated boundary walls, assuming a bottom temperature of 90oC, has been calculated and found to be 106.3 W. Contribution from the bottom convective zone itself to this total rate of heat loss is 69 W, which corresponds to 65% of the total value. Based on this rate, the estimated temperature drop during the period with no solar radiation present in a typical day is only 0.3oC. With such a small temperature drop, it is possible to extract the thermal energy stored in the bottom convective zone during the day time, continuously, while maintaining the stability of the solar pond. Keywords: Salinity-gradient solar pond; thermal insulation; desalination DOI: http://dx.doi.org/10.4038/sljp.v13i1.4212 Sri Lankan Journal of Physics, Vol. 13(1) (2012) 49-57","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"16 1","pages":"49"},"PeriodicalIF":0.0,"publicationDate":"2012-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78902911","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}
Regional and seasonal variations of precipitation systems are studied to understand the monsoonal rainfall in Bangladesh using Bangladesh Meteorological Department S-band weather radar Plan Position Indicator scans data and National Centers for Environmental Prediction reanalysis data. Precipitation systems are divided into arc-, line- and scattered-type according to their shape. The arc-type systems are dominant in the all four quadrants with maximum occurrence in the northeastern quadrant during the pre-monsoon period whereas the scattered-type systems are dominant in the southeast, northeast and southwest quadrants during the monsoon period. The arc-type systems are dominant in the northwest quadrant during the monsoon period. In the pre-monsoon period, the arc-type systems may be developed through the interaction of different air masses and the orographic effects in the presence of strong vertical wind shear between the 925 and 500 hPa levels and dry mid level. In the monsoon period, the scattered-type systems may be developed due to plenty of moisture supplied by low-level monsoon winds from the Bay of Bengal and the orographic effects in the presence of little or no remarkable vertical wind shear between the 925 and 500 hPa levels. Keywords: Precipitation systems; Bangladesh; Pre-monsoon; Monsoon; Radar DOI: http://dx.doi.org/10.4038/sljp.v12i0.4094 Sri Lankan Journal of Physics, Vol. 12 (2011) 7-14
{"title":"Regional and seasonal variations of precipitation systems in Bangladesh","authors":"M. Rafiuddin, H. Uyeda, M. Islam","doi":"10.4038/SLJP.V12I0.4094","DOIUrl":"https://doi.org/10.4038/SLJP.V12I0.4094","url":null,"abstract":"Regional and seasonal variations of precipitation systems are studied to understand the monsoonal rainfall in Bangladesh using Bangladesh Meteorological Department S-band weather radar Plan Position Indicator scans data and National Centers for Environmental Prediction reanalysis data. Precipitation systems are divided into arc-, line- and scattered-type according to their shape. The arc-type systems are dominant in the all four quadrants with maximum occurrence in the northeastern quadrant during the pre-monsoon period whereas the scattered-type systems are dominant in the southeast, northeast and southwest quadrants during the monsoon period. The arc-type systems are dominant in the northwest quadrant during the monsoon period. In the pre-monsoon period, the arc-type systems may be developed through the interaction of different air masses and the orographic effects in the presence of strong vertical wind shear between the 925 and 500 hPa levels and dry mid level. In the monsoon period, the scattered-type systems may be developed due to plenty of moisture supplied by low-level monsoon winds from the Bay of Bengal and the orographic effects in the presence of little or no remarkable vertical wind shear between the 925 and 500 hPa levels. Keywords: Precipitation systems; Bangladesh; Pre-monsoon; Monsoon; Radar DOI: http://dx.doi.org/10.4038/sljp.v12i0.4094 Sri Lankan Journal of Physics, Vol. 12 (2011) 7-14","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"7 1","pages":"7"},"PeriodicalIF":0.0,"publicationDate":"2012-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83235712","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}
ZnO films with different morphologies were synthesized electrochemically. The characteristics of ZnO films were studied. Addition of selected precursors into the electrolyte changes the morphology of ZnO films and yields hybrid organic-ZnO films. Highly porous ZnO films were obtained by extracting eosin Y from hybrid ZnO|eosinY films. Different organic dyes were used to sensitize ZnO films by means of utilization as light harvesting electrodes in dye sensitized photovoltaic cells. Photo-effects of sensitized ZnO electrodes were studied in I - |I 3 - redox-electrolyte. Among tested dyes an indoline dye D149 produced better performance. Keywords: EosinY; Hybrid ZnO films; D149 dye DOI: http://dx.doi.org/10.4038/sljp.v12i0.4095 Sri Lankan Journal of Physics, Vol. 12 (2011) 15-24
{"title":"Preparation of ZnO films with different morphologies and their applications in dye sensitized photo-voltaic cells","authors":"P. Sirimanne, E. Premalal","doi":"10.4038/SLJP.V12I0.4095","DOIUrl":"https://doi.org/10.4038/SLJP.V12I0.4095","url":null,"abstract":"ZnO films with different morphologies were synthesized electrochemically. The characteristics of ZnO films were studied. Addition of selected precursors into the electrolyte changes the morphology of ZnO films and yields hybrid organic-ZnO films. Highly porous ZnO films were obtained by extracting eosin Y from hybrid ZnO|eosinY films. Different organic dyes were used to sensitize ZnO films by means of utilization as light harvesting electrodes in dye sensitized photovoltaic cells. Photo-effects of sensitized ZnO electrodes were studied in I - |I 3 - redox-electrolyte. Among tested dyes an indoline dye D149 produced better performance. Keywords: EosinY; Hybrid ZnO films; D149 dye DOI: http://dx.doi.org/10.4038/sljp.v12i0.4095 Sri Lankan Journal of Physics, Vol. 12 (2011) 15-24","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"7 1","pages":"15"},"PeriodicalIF":0.0,"publicationDate":"2012-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79087059","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}
Gel electrolytes have emerged as potential candidates for various applications because they have appreciable ionic conductivities while having mechanical stability. In this study, the main objective was to find the role of Polyacrylonitrile (PAN) on performance of a gel polymer electrolyte in a Li rechargeable cell. A gel electrolyte was prepared using Ethylene Carbonate (EC), Propylene Carbonate (PC) and Lithium Trifluoromethanesulfonate (LiCF 3 SO 3 ) with PAN. A Li rechargeable cell having a conducting polymer cathode was assembled with the electrolyte. To observe the effect of PAN, parent liquid electrolyte was also used in a similar cell. It was seen that both cells have equal capacities but the stability with a liquid electrolyte is very low. This means PAN provides only dimensional stability. Room temperature conductivity of few samples was measured varying PAN amount. When PAN amount was increased, conductivity reduced. It may be due to blocking of ion transporting channels. It was interested to note that both gel electrolyte and its liquid electrolyte show maximum conductivity at slightly different salt concentrations for many temperatures. We conclude that addition of PAN does not disturb the performance of gel electrolyte in a battery; But it provides the mechanical stability for the liquid electrolyte. Keywords : Polyacrylonitrile; Ionic conductivity; Gel Polymer Electrolyte; Lithium Trifluoromethanesulfonate; Liquid Electrolyte DOI: http://dx.doi.org/10.4038/sljp.v12i0.4096 Sri Lankan Journal of Physics, Vol. 12 (2011) 25-31
{"title":"Effect of the polymer host, Polyacrylonitrile on the performance of Li rechargeable cells","authors":"K. Perera, K. Vidanapathirana, M. Dissanayake","doi":"10.4038/SLJP.V12I0.4096","DOIUrl":"https://doi.org/10.4038/SLJP.V12I0.4096","url":null,"abstract":"Gel electrolytes have emerged as potential candidates for various applications because they have appreciable ionic conductivities while having mechanical stability. In this study, the main objective was to find the role of Polyacrylonitrile (PAN) on performance of a gel polymer electrolyte in a Li rechargeable cell. A gel electrolyte was prepared using Ethylene Carbonate (EC), Propylene Carbonate (PC) and Lithium Trifluoromethanesulfonate (LiCF 3 SO 3 ) with PAN. A Li rechargeable cell having a conducting polymer cathode was assembled with the electrolyte. To observe the effect of PAN, parent liquid electrolyte was also used in a similar cell. It was seen that both cells have equal capacities but the stability with a liquid electrolyte is very low. This means PAN provides only dimensional stability. Room temperature conductivity of few samples was measured varying PAN amount. When PAN amount was increased, conductivity reduced. It may be due to blocking of ion transporting channels. It was interested to note that both gel electrolyte and its liquid electrolyte show maximum conductivity at slightly different salt concentrations for many temperatures. We conclude that addition of PAN does not disturb the performance of gel electrolyte in a battery; But it provides the mechanical stability for the liquid electrolyte. Keywords : Polyacrylonitrile; Ionic conductivity; Gel Polymer Electrolyte; Lithium Trifluoromethanesulfonate; Liquid Electrolyte DOI: http://dx.doi.org/10.4038/sljp.v12i0.4096 Sri Lankan Journal of Physics, Vol. 12 (2011) 25-31","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"13 1","pages":"25"},"PeriodicalIF":0.0,"publicationDate":"2012-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86791155","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 study was carried out to assess the effect of speed bumps on road traffic noise levels. Noise levels of different categories of vehicles were measured before and after speed bumps. Vehicles were categorized as passenger cars, passenger vans, three wheelers, motorcycles, and lorries. Depending on the vehicle category, the maximum noise level varied between 71 and 80 dB (A) under uninterrupted traffic conditions. The maximum noise level increased by over 5 dB (A) due to speed bumps for lorries and three wheelers. The results indicated that there is a considerable effect on the noise levels at a short distance from the speed bump perhaps due to the action taken by drivers to increase the speed of the vehicles. The equivalent noise level at 20 m from the speed bump was found to be on average 1.2 dB (A) higher than at the speed bump. The L Aeq values at 80 m after the speed bumps were found to be similar to the average noise level at the speed bump. Since speed bumps are often placed near schools and other public places, the noise impact should be taken into consideration when planning speed bumps. Keywords: Road noise; Environment; Motor ways; Vehicular traffic DOI: http://dx.doi.org/10.4038/sljp.v12i0.3155 Sri Lankan Journal of Physics, Vol. 12 (2011) 1-6
进行了一项研究，以评估减速带对道路交通噪音水平的影响。研究人员测量了不同种类车辆在设置减速带前后的噪音水平。车辆分为乘用车、客货车、三轮车、摩托车和卡车。在不间断的交通条件下，根据车辆类别的不同，最大噪音水平在71至80分贝(A)之间变化。由于卡车和三轮车的减速带，最大噪音水平增加了5分贝(A)以上。结果表明，在距离减速带较近的地方，由于驾驶员采取了提高车速的行动，对噪声水平有相当大的影响。距离减速带20 m处的等效噪声水平平均比减速带处高1.2 dB (A)。在减速带后80 m处的L Aeq值与减速带处的平均噪声水平相似。由于减速带通常设置在学校和其他公共场所附近，因此在规划减速带时应考虑到噪音影响。关键词:道路噪声;环境;运动方式;车辆交通DOI: http://dx.doi.org/10.4038/sljp.v12i0.3155斯里兰卡物理杂志，Vol. 12 (2011) 1-6
{"title":"Traffic Noise Enhancement due to Speed Bumps","authors":"Shanika Wewalwala, Upul J. Sonnadara","doi":"10.4038/SLJP.V12I0.3155","DOIUrl":"https://doi.org/10.4038/SLJP.V12I0.3155","url":null,"abstract":"A study was carried out to assess the effect of speed bumps on road traffic noise levels. Noise levels of different categories of vehicles were measured before and after speed bumps. Vehicles were categorized as passenger cars, passenger vans, three wheelers, motorcycles, and lorries. Depending on the vehicle category, the maximum noise level varied between 71 and 80 dB (A) under uninterrupted traffic conditions. The maximum noise level increased by over 5 dB (A) due to speed bumps for lorries and three wheelers. The results indicated that there is a considerable effect on the noise levels at a short distance from the speed bump perhaps due to the action taken by drivers to increase the speed of the vehicles. The equivalent noise level at 20 m from the speed bump was found to be on average 1.2 dB (A) higher than at the speed bump. The L Aeq values at 80 m after the speed bumps were found to be similar to the average noise level at the speed bump. Since speed bumps are often placed near schools and other public places, the noise impact should be taken into consideration when planning speed bumps. Keywords: Road noise; Environment; Motor ways; Vehicular traffic DOI: http://dx.doi.org/10.4038/sljp.v12i0.3155 Sri Lankan Journal of Physics, Vol. 12 (2011) 1-6","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"7 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2012-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79608914","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}
An attempt has been made to predict the high impact rainfall events of summer monsoon over Bangladesh using the Fifth-Generation PSU/NCAR Mesoscale Model (MM5) conducting two historical rainfall events on 11 June 2007 and 14 September 2004.The model was run on two way triple-nested domains at 45, 15, 5 km horizontal resolutions using Anthes-Kuo cumulus parameterization schemes (CPS) with MRF planetary boundary layer (PBL). Bangladesh is the main focus area in this study. Thus Bangladesh is taken as inner most (D3) domain with 5 km horizontal resolution to study the variability of predicted rainfall. The model predicted rainfall was compared with TRMM 3B42V6 and BMD observed rainfall. The MM5 model produces realistic prediction of high impact rainfall events in terms of intensity and structure. The predictions have been made for Day-1 (24-h), Day-2 (48-h) and Day-3 (72-h) in advance. The predictions are more accurate for Day-1 (24-h) and Day-2 (48-h). The prediction deteriorates as the prediction time increases. The prediction has been found to be good even for longer prediction time [(more than Day-2 (48-h)] for relatively stronger case (i.e., 11 June 2007). The prediction accuracy is low for relatively weak case (i.e., 14 September 2004) specially over Day-2 (48-h) of prediction. The prediction may be updated in every 24 hours which would provide more realistic prediction. Keywords: Prediction; Rainfall; High Impact; TRMM; MM5 Model DOI: http://dx.doi.org/10.4038/sljp.v12i0.3122 Sri Lankan Journal of Physics, Vol. 12 (2011) 43-58
{"title":"Prediction of high impact rainfall events over Bangladesh using high resolution MM5 model","authors":"Ahasan, M. Chowdhury, D. Quadir","doi":"10.4038/SLJP.V12I0.3122","DOIUrl":"https://doi.org/10.4038/SLJP.V12I0.3122","url":null,"abstract":"An attempt has been made to predict the high impact rainfall events of summer monsoon over Bangladesh using the Fifth-Generation PSU/NCAR Mesoscale Model (MM5) conducting two historical rainfall events on 11 June 2007 and 14 September 2004.The model was run on two way triple-nested domains at 45, 15, 5 km horizontal resolutions using Anthes-Kuo cumulus parameterization schemes (CPS) with MRF planetary boundary layer (PBL). Bangladesh is the main focus area in this study. Thus Bangladesh is taken as inner most (D3) domain with 5 km horizontal resolution to study the variability of predicted rainfall. The model predicted rainfall was compared with TRMM 3B42V6 and BMD observed rainfall. The MM5 model produces realistic prediction of high impact rainfall events in terms of intensity and structure. The predictions have been made for Day-1 (24-h), Day-2 (48-h) and Day-3 (72-h) in advance. The predictions are more accurate for Day-1 (24-h) and Day-2 (48-h). The prediction deteriorates as the prediction time increases. The prediction has been found to be good even for longer prediction time [(more than Day-2 (48-h)] for relatively stronger case (i.e., 11 June 2007). The prediction accuracy is low for relatively weak case (i.e., 14 September 2004) specially over Day-2 (48-h) of prediction. The prediction may be updated in every 24 hours which would provide more realistic prediction. Keywords: Prediction; Rainfall; High Impact; TRMM; MM5 Model DOI: http://dx.doi.org/10.4038/sljp.v12i0.3122 Sri Lankan Journal of Physics, Vol. 12 (2011) 43-58","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"12 1","pages":"43"},"PeriodicalIF":0.0,"publicationDate":"2012-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82889174","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}
Potentiostatic electrodeposition of cuprous oxide (Cu 2 O) thin films in aqueous acetate baths was investigated to study the conduction type, n-type or p-type, and the p-n homojunction formation of the films, using photocurrent spectral response and capacitance-voltage measurements to determine the conduction type. The study reveals that not only the pH value but also the cupric ion concentration of the acetate bath determines the conduction type of the films. Electrodeposition of p-n homojunction of Cu 2 O is possible with a single or a two step electrodeposition. Both parameters of the deposition bath, pH and cupric ion concentration, can be adjusted to control conduction type and p-n homojunction formation of Cu 2 O films. Keywords : cuprous oxide; electrodeposition; n- and p-type; spectral response; p-n homojunction DOI: http://dx.doi.org/10.4038/sljp.v9i0.2509 Sri Lanka Journal of Physics Vol.9 (2008) pp.35-46
{"title":"Electrodeposition of p-type, n-type and p-n Homojunction Cuprous Oxide Thin Films","authors":"K. Jayathileke, W. Siripala, J. Jayanetti","doi":"10.4038/SLJP.V9I0.2509","DOIUrl":"https://doi.org/10.4038/SLJP.V9I0.2509","url":null,"abstract":"Potentiostatic electrodeposition of cuprous oxide (Cu 2 O) thin films in aqueous acetate baths was investigated to study the conduction type, n-type or p-type, and the p-n homojunction formation of the films, using photocurrent spectral response and capacitance-voltage measurements to determine the conduction type. The study reveals that not only the pH value but also the cupric ion concentration of the acetate bath determines the conduction type of the films. Electrodeposition of p-n homojunction of Cu 2 O is possible with a single or a two step electrodeposition. Both parameters of the deposition bath, pH and cupric ion concentration, can be adjusted to control conduction type and p-n homojunction formation of Cu 2 O films. Keywords : cuprous oxide; electrodeposition; n- and p-type; spectral response; p-n homojunction DOI: http://dx.doi.org/10.4038/sljp.v9i0.2509 Sri Lanka Journal of Physics Vol.9 (2008) pp.35-46","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"17 1","pages":"35"},"PeriodicalIF":0.0,"publicationDate":"2010-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80583750","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}
Solid polymer electrolytes are considered to be very appealing candidates for numerous applications such as batteries, artificial muscles and super capacitors. For applications, the voltage limits between the oxidation and reduction are very important. The voltage limits are taken as the positions where oxidation and reduction occurs. Those two positions can be traced using a cyclic voltammogram. The solid polymer electrolyte under investigation comprised of polyacrylonitrile (PAN), ethylene carbonate (EC). propylene carbonate (PC) and lithium trifluoromethanesulfoinate (L i CF 3 SO 3 – L i TF). All the preparation steps were carried out in side an Argon filled glove box. Electrolyte film was sandwiched in a brass sample cell holder in between a Li electrode and one of an inert electrode made of stainless steel, nickel, platinum, copper and aluminium. Lithium was used as the reference and counter electrodes while the inert electrode was used as the working electrode. Cyclic voltammetry measurements were taken in the potential range, 2.0 V – 4.9 V vs L i . A good stability window was seen when the stainless steel electrodes were used. DOI: http://dx.doi.org/10.4038/sljp.v9i0.2505 Sri Lanka Journal of Physics Vol.9 (2008) pp.1-6
固体聚合物电解质被认为是许多应用的非常有吸引力的候选者，如电池，人造肌肉和超级电容器。对于应用，氧化和还原之间的电压限制是非常重要的。电压限值作为氧化和还原发生的位置。这两个位置可以用循环伏安图来追踪。研究了由聚丙烯腈(PAN)、碳酸乙烯(EC)组成的固体聚合物电解质。碳酸丙烯(PC)和三氟甲烷磺酸锂(L i CF 3 SO 3 - L i TF)。所有的准备步骤都在一个充满氩气的手套箱中进行。电解质膜被夹在一个黄铜样品电池支架中，夹在一个锂电极和一个由不锈钢、镍、铂、铜和铝制成的惰性电极之间。采用锂作为参比电极和对电极，惰性电极作为工作电极。在2.0 V ~ 4.9 V vs L i电位范围内进行循环伏安法测量。当使用不锈钢电极时，可以看到良好的稳定性窗口。DOI: http://dx.doi.org/10.4038/sljp.v9i0.2505斯里兰卡物理杂志Vol.9 (2008) pp.1-6
{"title":"Determination of electrochemical stability window of polyacrylonitrile based polymer system for different electrodes","authors":"K. Perera, K. Vidanapathirana, M. Dissanayake","doi":"10.4038/SLJP.V9I0.2505","DOIUrl":"https://doi.org/10.4038/SLJP.V9I0.2505","url":null,"abstract":"Solid polymer electrolytes are considered to be very appealing candidates for numerous applications such as batteries, artificial muscles and super capacitors. For applications, the voltage limits between the oxidation and reduction are very important. The voltage limits are taken as the positions where oxidation and reduction occurs. Those two positions can be traced using a cyclic voltammogram. The solid polymer electrolyte under investigation comprised of polyacrylonitrile (PAN), ethylene carbonate (EC). propylene carbonate (PC) and lithium trifluoromethanesulfoinate (L i CF 3 SO 3 – L i TF). All the preparation steps were carried out in side an Argon filled glove box. Electrolyte film was sandwiched in a brass sample cell holder in between a Li electrode and one of an inert electrode made of stainless steel, nickel, platinum, copper and aluminium. Lithium was used as the reference and counter electrodes while the inert electrode was used as the working electrode. Cyclic voltammetry measurements were taken in the potential range, 2.0 V – 4.9 V vs L i . A good stability window was seen when the stainless steel electrodes were used. DOI: http://dx.doi.org/10.4038/sljp.v9i0.2505 Sri Lanka Journal of Physics Vol.9 (2008) pp.1-6","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"18 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2010-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81913141","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}
Using a simple thermodynamic upper bound efficiency model for the conversion of solar energy into work, the best material for a converter was obtained. Modifying the existing detailed terrestrial application model of direct solar radiation to include an atmospheric transmission coefficient with cloud factors and a maximum concentration ratio, the best shape for a solar concentrator was derived. Using a Carnot engine in detailed space application model, the best shape for the mirror of a concentrator was obtained. A new conversion model was introduced for a solar chimney power plant to obtain the efficiency of the power plant and power output. DOI: http://dx.doi.org/10.4038/sljp.v9i0.2510 Sri Lanka Journal of Physics Vol.9 (2008) pp.47-60
{"title":"Thermodynamic investigation of solar energy conversion in to work","authors":"W. Dayanga, K. Gamalath","doi":"10.4038/SLJP.V9I0.2510","DOIUrl":"https://doi.org/10.4038/SLJP.V9I0.2510","url":null,"abstract":"Using a simple thermodynamic upper bound efficiency model for the conversion of solar energy into work, the best material for a converter was obtained. Modifying the existing detailed terrestrial application model of direct solar radiation to include an atmospheric transmission coefficient with cloud factors and a maximum concentration ratio, the best shape for a solar concentrator was derived. Using a Carnot engine in detailed space application model, the best shape for the mirror of a concentrator was obtained. A new conversion model was introduced for a solar chimney power plant to obtain the efficiency of the power plant and power output. DOI: http://dx.doi.org/10.4038/sljp.v9i0.2510 Sri Lanka Journal of Physics Vol.9 (2008) pp.47-60","PeriodicalId":21880,"journal":{"name":"Sri Lankan Journal of Physics","volume":"40 1","pages":"47"},"PeriodicalIF":0.0,"publicationDate":"2010-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75041852","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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