Papers by Kirthi Tennakone
Organic Electronics, 2019
Current studies on dye-sensitized solar cells are mainly focus on fabricating low-cost cell with ... more Current studies on dye-sensitized solar cells are mainly focus on fabricating low-cost cell with high performances. Cost of dye-sensitized solar cells depends mainly on the counter electrode material where the best catalyst for triiodide reduction at the counter electrode is platinum, which is highly expensive. Among various non-platinum counter electrode catalysts, carbon-based materials stand out to be the best alternative as far as low-cost and ready abundance are concerned. A simple procedure is described for producing high electrical conductivity activated charcoal from coconut shells and depositing it on conducting tin oxide glass as a thin film, to be used as the counter electrode for dye-sensitized electrolytic solar cells. The activated coconut shell charcoal catalytic layer which is subjected to this work had very good adhesion between the particles as well as to the conducting tin oxide glass substrate. The efficiency of 7.85% obtained exceeds, values obtained from other forms of activated carbon derived from bio-materials.
Journal of Solid State Chemistry, 1985
Etude de la conductivite electrique de monocristaux entre 140 et 280°C. Le transport electronique... more Etude de la conductivite electrique de monocristaux entre 140 et 280°C. Le transport electronique est probablement du a un processus de sauts (mecanisme de petits polarons)
Bulletin of the American Physical Society, 2017
Georgia journal of science, 2020
The path of maximum for the annular eclipse of December 26th,2019, includes land areas of Saudi A... more The path of maximum for the annular eclipse of December 26th,2019, includes land areas of Saudi Arabia, India, Sri Lanka, Sumatra, Malasia, Philippines, and Guam; that is, in addition to passing through the Indian and Pacific oceans. A team of interested scientists travel to the city of Jaffna, Sri Lanka, and report their measurements. Jaffna, itself, happens to be on the path of maximum. Spectral intensity variation, surface ozone and hydrogen H-alpha measurements conducted are compared to prior experiments. In our previous experiments, carried out at the University of West Georgia, Carrollton, Georgia, during the time of the solar eclipse of 21st August, 2017, demonstrated that the integrated spectral irradiance in defined wavelength ranges in the ultraviolet and visible reached a minimum at maximum obscuration of the sun, whereas in an infrared range it was maximum. In a surface ozone measurement, a minimum in ozone concentration occurred thirty minutes after the instant of maximum obscuration. This Jafna eclipse allows us an opportunity to conduct an additional trial to previous observations. The results of measurements as well as the journey to the observation camp are discussed
The analysis of COVID-19 statistics in different regions of the world with the intention of under... more The analysis of COVID-19 statistics in different regions of the world with the intention of understanding the trend of progression of the pandemic is a task of paramount importance. Publicly available data includes cumulative number of cases, new cases each day, and the mortality. Extracting information from this data necessitates mathematical modeling. In this note a simple technique is adopted to determine the trend towards stabilized elimination of the infection, as implicated by saturation of the cumulative number of cases. Results pertaining to several representative regions of the world are presented. In several regions, evidence there to the effect that the pandemic will come to an end. The estimated saturation values of the cumulative numbers are indicated.
Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, 1982
Long-chain normal aliphatic alcohols are found to suppress photocorrosion and increase the effici... more Long-chain normal aliphatic alcohols are found to suppress photocorrosion and increase the efficiency of a cuprous oxide photoelectrochemical cell with aqueous thiocyanate solution as the electrolyte. It is suggested that alcohols inhibit corrosion by surface adsorption.
Journal of the National Science Foundation of Sri Lanka, 1986
It is found that when a semiconductor electrode surface in a photoelectrochemical cell is coated ... more It is found that when a semiconductor electrode surface in a photoelectrochemical cell is coated with a dye that can transfer a charge carrier upon excitation into an energy band and if a layer of a second dye that readily transfers the energy of photon excitation into an inner one by resonance is deposited on top of the first dye, then stability and quantum efficiency of photocurrent are both improved. Observations based on dye coated CuCNS photocathodes are presented to illustrate the phenomenon. Photochemical processes involved are discussed.
Journal of the National Science Foundation of Sri Lanka, 1986
I Solid ferric femcyanide which is dark green in colour undergoes reversible transition into a ye... more I Solid ferric femcyanide which is dark green in colour undergoes reversible transition into a yellowish white form at 3 4 0~~. This phase change is also associated with a transition in the electrical conductivlfy. It is suggested that in the green form carbon in CN-is linked to high spin Fe and In the yellow form this linkage is reversed.
Journal of the National Science Foundation of Sri Lanka, 1987
Traces of water a. an impurity is found to increase the clcctronic conductivity of the charge tra... more Traces of water a. an impurity is found to increase the clcctronic conductivity of the charge transfer solid methylene blue. It is found that hydrogen bonded and free molecules of water decrease the thermal activation energy of charge carriers in different ways. Theoretical arguments based on the small polaron theory are given to explain the mechanism of conduction.
Journal of the National Science Foundation of Sri Lanka, 2017
aerodynamic optimisation to minimise the speed of descent on of the dispersal of seeds of many sp... more aerodynamic optimisation to minimise the speed of descent on of the dispersal of seeds of many species in relation to this symmetry is broken either spontaneously or intrinsically. In the former situation, seeds have no geometrical right-left asymmetry, but an initial instability chooses one sense of rotation (right or left). Whereas in the latter, geometrical asymmetry dictates the sense of rotation. Seeds of the maple presented to explain the motion. Seeds of dipterocarps, conifers and some genera of apocyanaceae and magnoliaceae are found seed fall. In dipterocarps, conifers and magnoliaceae, both right-handed and left-handed seeds are produced in the same tree but correlated to the handedness of the sprial phyllotaxy of the branch that bears the fruit. Apocyanaceae is found to be unique and seeds of all genera have the same handedness. and theoretical interpretations are presented to illustrate the relationship of right-left asymmetry to the aerodynamics of optimisation in practical aerodynamics.
Journal of the National Science Foundation of Sri Lanka, 1983
Conductivity characteristics of ferric molybdatc is studied. It is found that this material under... more Conductivity characteristics of ferric molybdatc is studied. It is found that this material undergoes a semiconductor to metal transition a t-1390C.
Ceylon Medical Journal, 2018
Introduction Dengue is a mosquito-borne viral infection endemic in tropical and subtropical regio... more Introduction Dengue is a mosquito-borne viral infection endemic in tropical and subtropical regions,now spreading at epidemic proportions causing a major health issue in Sri Lanka and elsewhere. No effective vaccine or a curative antiviral drug is available to prevent or treat the disease. The only way of mitigating dengue at present, is through mosquito eradication and educating the public on preventive measures which can minimize the cycle of transfer. Objectives A theoretical model of dengue with simple mathematics is presented to gain a quantitative understanding of the pattern of dengue outbreaks in Sri Lanka and suggest control measures. Method The statistics on incidence of the disease reported by the Epidemiology Unit is analyzed using the model. Despite simplicity, the model possesses explanatory and predictive capacity, enabling determination of crucial parameters. The model shows that the "infectives" increase exponentially in an outbreak, provided the number of vectors per human exceeds a threshold, illustrating not only vector eradication but measures which minimize their biting frequency and preventing prolonged survival are effective safeguards. Results In a population consisting of 75% who are susceptible, the threshold is estimated to be 20 mosquitos per person. Conclusions The model showed that the endemic equilibrium of the system can occur at any level. As demographic changes escalate mosquito breeding, they infect more and more susceptible people. The consequent increase in virus replication induces new strains broadening the genetic diversity of the virus and helping it to overcome the human immune response. The increasing endemicity of dengue due to this is demonstrated by the model.
Ceylon Journal of Science, 2018
Journal of Physics C: Solid State Physics, 1983
A simple theory is presented to explain the observation that heavy metal ferrocyanides and ferric... more A simple theory is presented to explain the observation that heavy metal ferrocyanides and ferricyanides become n- and p-type semiconductors respectively on absorption of trace quantities of water.
Solar Energy Materials, 1984
The carbon dioxide reduction capacity of powder suspensions of n-TiC 2 coated with different meta... more The carbon dioxide reduction capacity of powder suspensions of n-TiC 2 coated with different metals is studied. It is found that the highest yield of formaldehyde is obtained with Hg coated TiC 2. Theoretical arguments are given to explain the results.
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Papers by Kirthi Tennakone