Sri Lankan Journal of Physics最新文献_第6页

Orographic features of global atmospheric fair weather electrical parameters over different places of Sri Lanka 斯里兰卡不同地区全球大气晴朗天气电参数的地形特征

Sri Lankan Journal of Physics Pub Date : 2012-07-19 DOI: 10.4038/SLJP.V13I1.2104

Deepti Saxena, R. Yadav, Adarsh Kumar

{"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}

引用次数: 4

Optimization of thermal insulation of a small-scale experimental solar pond 小型实验太阳能池隔热性能优化

Sri Lankan Journal of Physics Pub Date : 2012-07-19 DOI: 10.4038/SLJP.V13I1.4212

N. Jayatissa, R. Attalage, P. Hewageegana, P. Perera, M. A. Punyasena

{"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}

引用次数: 1

Regional and seasonal variations of precipitation systems in Bangladesh 孟加拉国降水系统的区域和季节变化

Sri Lankan Journal of Physics Pub Date : 2012-02-17 DOI: 10.4038/SLJP.V12I0.4094

M. Rafiuddin, H. Uyeda, M. Islam

{"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}

引用次数: 2

Preparation of ZnO films with different morphologies and their applications in dye sensitized photo-voltaic cells 不同形貌ZnO薄膜的制备及其在染料敏化光伏电池中的应用

Sri Lankan Journal of Physics Pub Date : 2012-02-17 DOI: 10.4038/SLJP.V12I0.4095

P. Sirimanne, E. Premalal

引用次数: 2

Effect of the polymer host, Polyacrylonitrile on the performance of Li rechargeable cells 高分子基质聚丙烯腈对锂电池性能的影响

Sri Lankan Journal of Physics Pub Date : 2012-02-17 DOI: 10.4038/SLJP.V12I0.4096

K. Perera, K. Vidanapathirana, M. Dissanayake

{"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}

引用次数: 5

Traffic Noise Enhancement due to Speed Bumps 由于减速带而提高交通噪音

Sri Lankan Journal of Physics Pub Date : 2012-02-16 DOI: 10.4038/SLJP.V12I0.3155

Shanika Wewalwala, Upul J. Sonnadara

{"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}

引用次数: 10

Prediction of high impact rainfall events over Bangladesh using high resolution MM5 model 利用高分辨率MM5模式预测孟加拉国高影响降雨事件

Sri Lankan Journal of Physics Pub Date : 2012-02-15 DOI: 10.4038/SLJP.V12I0.3122

Ahasan, M. Chowdhury, D. Quadir

{"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}

引用次数: 5

Electrodeposition of p-type, n-type and p-n Homojunction Cuprous Oxide Thin Films p型、n型和p-n型氧化亚铜薄膜的电沉积

Sri Lankan Journal of Physics Pub Date : 2010-12-09 DOI: 10.4038/SLJP.V9I0.2509

K. Jayathileke, W. Siripala, J. Jayanetti

引用次数: 24

Determination of electrochemical stability window of polyacrylonitrile based polymer system for different electrodes 不同电极条件下聚丙烯腈基聚合物体系电化学稳定窗口的测定

Sri Lankan Journal of Physics Pub Date : 2010-12-09 DOI: 10.4038/SLJP.V9I0.2505

K. Perera, K. Vidanapathirana, M. Dissanayake

{"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}

引用次数: 1

Thermodynamic investigation of solar energy conversion in to work 对太阳能转换成功的热力学研究

Sri Lankan Journal of Physics Pub Date : 2010-12-09 DOI: 10.4038/SLJP.V9I0.2510

W. Dayanga, K. Gamalath

引用次数: 0