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Wimalagunasekara T.U.,Wayamba University of Sri Lanka | Edirisinghe J.C.,Wayamba University of Sri Lanka | Wijesuriya W.,Rubber Research Institute of Sri Lanka
Journal of Rubber Research | Year: 2012

Farmers ' individual choices relating to agronomic practices are influenced by socio economic factors related to the farmer and his family as well as physical factors relating to the farm. Many studies that investigate these choices fail to recognise the importance of neighbours' influence on decision making. This research attempted to determine whether there exists a relationship between one farmer's choice and the choices of the neighbouring farmers in adoption of fertiliser recommendations in rubber cultivation of a sample of 393 smallholder farmers in one of the non-traditional rubber growing districts in Sri Lanka. Major aims of the research were to explicitly model spatial relationships in adoption of fertiliser application in rubber cultivation and to identify the factors that influence them. Bayesian Spatial Autoregressive Probit (SARP) model was used in the study. The neighbours ' influence was measured in terms of a spatial correlation coefficient. Results revealed that the spatial correlation coefficient was positive and statistically significant, implying a strong influence by neighbours on a decision by a particular farmer. The results also highlighted the importance of socio economic factors and soil characteristics in adopting these practices. Source

Siriwardena S.,Universiti Sains Malaysia | Siriwardena S.,Rubber Research Institute of Sri Lanka | Ismail H.,Universiti Sains Malaysia | Ishiaku U.,Universiti Sains Malaysia
Polymer International | Year: 2011

White rice husk ash (WRHA) and silica filled ethylene-propylene-diene terpolymer (EPDM) vulcanizates were prepared using a laboratory size two-roll mill. Curing characteristics and physical properties of vulcanizates were studied with respect to the filler loading and filler type. Filler loading was varied from 0-50 parts per hundred resin (phr) at 10phr intervals. Curing was carried out using a semi-efficient vulcanization system in a Monsanto rheometer. Enhancement of the curing rate was observed with increasing WRHA loading, whereas the opposite trend was observed for silica-filled vulcanizates. It was also indicated by the maximum torque and Mooney viscosity results that WRHA offers processing advantages over silica. Compared to the silica-filled vulcanizates, the effect of filler loading on the physical properties of WRHA-filled vulcanizates was not significant. According to these observations, WRHA could be used as a diluent filler for EPDM rubber, while silica can be used as a reinforcing filler. © 2001 Society of Chemical Industry. Source

Jayasuriya M.M.,Rubber Research Institute of Sri Lanka | Hourston D.J.,Loughborough University
Journal of Applied Polymer Science | Year: 2012

The effects of the PMMA content and the cross-linker level in the poly(methylmethacrylate) component on the dynamic and physico-mechanical properties of semi-2 interpenetrating polymer networks based on natural rubber and poly(methylmethacrylate) were determined. The miscibility of the components in these semi-2 interpenetrating polymer networks was determined using the loss tangent data, obtained from dynamic mechanical thermal analysis and the interphase contents were calculated from modulated scanning calorimetric data. Some component mixing in these semi-2 interpenetrating polymer networks was evident from these modulated differential scanning calorimetric and dynamic mechanical thermal analysis data. The degree of component mixing increased with cross-linker level in the PMMA phase. The PMMA content in the semi-2 IPNs has a significant effect on the tensile and hysteresis behavior of these semi-2 interpenetrating polymer networks. © 2011 Wiley Periodicals, Inc. Source

Kudaligama K.V.V.S.,Rubber Research Institute of Sri Lanka | Thurul W.M.,Thurul Safe Environment | Yapa P.A.J.,University of Sri Jayewardenepura
Journal of Rubber Research | Year: 2010

Crepe rubber industry is one of the major water polluting industries in all rubber growing countries. There is a necessity to develop suitable treatment technologies for the management of this problem. Covered Activated Ditch (CAD) type test reactors set with Bio-brush media are very effective in rubber factory wastewater treatment. Out of four organic loading rates (OLR) and five specific surface areas (SSA) of media tested respectively, Bio-brush media with 200 m2/m3 SSA under 1.0 COD kg/m3/d OLR was selected as the best for CAD reactors and the average COD removal achieved was about 89%. Results revealed that at higher OLR, correction ofpH could be avoided for an efficient treatment and reactors with higher SSA of media were able to tolerate organic shock loads comparatively. The efficiency of treatment increased with increasing SSA of media and no special cycles were observed in removing biomassfrom the test reactor under any of the four OLRs tested. During maturation, chemical oxygen demand (COD), pH and suspended solids (SS) of treated effluent with 200 m 2/m3 SSA were about 100 mg/L, 6.7-7.2 and 26-43 mg/L respectively which were below the maximum desirable levels stipulated by the Central Environmental Authority of Sri Lanka. Apart from the rubber industry, CAD reactors could also be used for treating biodegradable liquid waste such as waste from the palm oil industry, rice processing industry, sugar industry and others. Source

Liyanage K.K.,World Agroforestry Center | Liyanage K.K.,Mae Fah Luang University | Liyanage K.K.,CAS Kunming Institute of Botany | Liyanage K.K.,Rubber Research Institute of Sri Lanka | And 10 more authors.
Forest Pathology | Year: 2016

Powdery mildew disease of rubber trees affects young rubber leaves, buds, inflorescences and other immature tissues reducing rubber latex yields by up to 45%. The disease is present in all rubber-growing regions, with a high incidence rate in subtropical environments. The causal agent of powdery mildew disease of rubber trees was first described as Oidium heveae, but later research on the morphological characteristics suggests that O. heveae was in the past confused with Erysiphe quercicola. However, the most appropriate classification is still under debate between the genera Golovinomyces or Podosphaera. Molecular and phylogenetic analyses have established some relationships between rubber powdery mildew fungus and other powdery mildew species, but the generic sexual state of rubber powdery mildew fungus has not yet been established. Rubber powdery mildew conidia are wind-spread spores that are produced in great numbers when growth conditions of the disease are favourable. The optimum conditions for conidial germination are 97-100% relative humidity and temperatures between 25 and 28°C. While some newly bred rubber clones have shown resistance to the disease, it can also be controlled with a number of fungicides and biological control agents. It is clear from recent knowledge about climate-fungus relationships that changes in weather strongly influence disease incidence and severity. The aim of this review is to highlight the classification conflicts, main causes and influencing factors behind the disease spreading, as well as draw attention to the impact of weather changes on the outbreaks of the disease. The information in this review will be helpful to adopt better control measures of the powdery mildew disease of rubber, especially in higher humidity areas, thereby minimizing the loss of rubber yields due to this disease. © 2016 Blackwell Verlag GmbH. Source

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