Browsing by Author "Withanage, N.S."
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Item Applicability of Estimating Evapo-Transpiration using Different Methods for Badulla Region(Uva Wellassa University of Sri Lanka, 2012) Withanage, N.S.; Dharmadasa, R.A.P.I.S.; Kodikara, K.M.S.Potential evapo-transpiration (PET) is an essential tool widely used in hydrological studies. The magnitude and the variation of PET are required for water resources planning and management, proper irrigation scheduling, assessment of irrigation efficiency in different irrigation methods and estimation of water supply requirements of irrigation projects. Owing to the wide ranging inconsistency in meteorological data collection procedures and standards, two types of PET equations have been used by different authors; empirical equations with lower data requirement and physically-based equations that require more data. The International Commission for Irrigation and Drainage (ICID), the Food and Agriculture Organization (FAO) and the American Society of Civil Engineers (ASCE) have adopted the Penman-Monteith (PM) method as the standard way to compute PETfrom climate data. PM is widely used as it is predominantly a physically-based approach that can be used globally and that has been widely tested using Lysimeter data from a wide range of climatic conditions (Itenfisu et al., 2000). When the data are limited, PET is calculated by estimating the absent parameters indirectly from the available data to use in PM equation (Allen et al., 1998) or by the use of less data intensive empirical equations some of which are based on temperature (e.g. Thornthwaite, 1948; Blaney and Criddle, 1950; Romanenko, 1961; Hargreaves, 1975 and Kharrufa, 1985). It is generally accepted that empirical formulae may be reliable in the areas and over the periods for which they were developed, but large errors can be expected when they are extrapolated to other climatic areas without recalibrating the constants involved in the formulae (Hounam, 1971). There is a scarcity of accurate meteorological data in Uva Province of Sri Lanka for estimating PET using standard PM method. Therefore, this research was conducted to analyze and compare temperature-based methods with the standard Modified Penman- Monteith (MPM) method and to select the best equation/s which can be applied to estimate the PET of the region.Item Developing an Effective Specific Gravity Measuring System for Solid Tyre Manufacturing Process(Uva Wellassa University of Sri Lanka, 2020) Palliyage, R.P.; Withanage, N.S.; Wijesundara, K.Solid tyres are non-pneumatic tyres which are not filled with air. It consists of major three layers such as heel, cushion, and tread. The main steps of the solid tyre manufacturing process are compound warming, compound feeding, tyre rolling, curing, and final inspection. During compound warming, the specific gravity of the warmed compound is tested. According to that value, the required mass of compound for tyre is measured. Then It is transferred to the feeding mill and after that, it is transferred to tyre rolling. In the solid tyre manufacturing process, the specific gravity of the warmed compound should be measured before the tyre rolling. The current production process takes a total of 7 min for measuring specific gravity, which is higher than tyre rolling time. So, the current specific gravity measuring system is un-effective for the process. If the weight will be less than the required amount, tyre can be scrapped. It leads to economic losses to the company. Therefore, minimizing the total time for specific gravity measuring is important to increase productivity. In this research, eight types of experiments were designed to find the optimum time for a specific gravity measuring process. In each experiment major four parameters were considered, such as curing temperature, curing time, cooling water temperature, and cooling time. In this experiments three different curing temperatures (180 ⁰C, 190 ⁰C, 200 ⁰C), two different curing times (2, 3 min), two different cooling water temperatures (30 ⁰C, <10 ⁰C) and five different cooling times (0, 1, 2, 3, 4 min) were used to test the specific gravity of the compound samples under 8 different experiments. The results revealed that the optimum curing temperature is 190 ⁰C, curing time is 2 min., cooling time is 2 min., and the cooling water temperature is <10 ⁰C. The total time takes by specific gravity measuring could be minimized to 4 min. It would be profitable for the company in many ways compared to the current 7 min operation. Keywords: Cooling time, Curing time, Curing temperature, Specific gravity, Tyre manufacturingItem Development of a Composite Board by Mixing Cement, Coir Fiber and Calcium Carbonate(Uva Wellassa University of Sri Lanka, 2013) Jathunarachchi, P.N.; Withanage, N.S.; Fernando, J.A.K.M.Coir fiber products have a great potential in domestic and international market in view of the world trend towards natural products. Now a days coir fiber reinforced cement boards are becoming more popular than harmful synthetic fiber reinforced cement boards. Their natural abundance, relative cheapness and instantaneous replacing ability are the strongest arguments to utilize them in the construction industry in Sri Lanka. In the Acetylene plant, calcium carbonate is the waste material. Due to its excellent filling ability and the availability, it can be used in composite board manufacturing. For the development of the coir industry and to add value to the wasting coir surplus and calcium carbonate waste from acetylene plant, it is required to investigate the possibility of using coir fiber and calcium carbonate in composite board manufacturing. This research was aimed at developing a coir fiber reinforced composite board by mixing cement, coir fiber and calcium carbonate via the determination of weight fraction of the constituents of the boards. In addition to that, the effect of various coir fiber types (Bristle fiber, Mattress fiber and Baby fiber) as well as various calcium carbonate ratios (10%, 20% and 25%) on board properties such as dry weight, thickness, density, water absorption and flexural strength were also determined. Then the possibility of using these composites in ceiling sheet manufacturing was studied. Methodology Three types of coir fibers (Bristle fiber, Mattress fiber and Baby fiber), Calcium Carbonate (CaCO3) and Ordinary Portland cement (OPC) were obtained locally. Calcium carbonate precipitates were ground and sieved using 0.5 mm sieve to obtain the calcium carbonate in powder form. Then bristle fiber and the mattress fiber were cut into 2 cm length in pieces. Preliminary studies were conducted to find out the suitable composition for the development of composite board using cement, coir fiber andcalcium carbonate. In the preliminary trials ten different composites were manufactured and evaluated its weight and other physical properties and it was observed that the composite C34B was not acceptable condition. Accordingly nine composite mixtures were selected for further testing of the physico-mechanical properties. Compositions of mixtures were given in table no 1. Ordinary Portland cement and calcium carbonate in various ratios were manually mixed with water and also coir fiber. The mixing of these ingredients was continually done until the cement, calcium carbonate and fiber paste were uniformly distributed. Then the mixture was spread out in a metal frame placed on a polythene sheet to form a board using mason’s trowel. The board was inserted in between the two plates of hydraulic press machine and it was densified by compressing it to a desired thickness using a hydraulic press. The pressure was maintained for 24 hours. The boards were removed from the press after 24 hours and soaked in the water for 7 days for curing and conditioning. The cement: calcium carbonate ratios were varied in 400:160,400:120,400:50 while cement and CaCO3 to fiber ratio was kept at a constant (10%) and the fiber types were also changed. The amount of water was fixed at 400ml per board.Item Development of a High Abrasion Resistance Shoe Sole Incorporating Four Different Silica Grades(Uva Wellassa University of Sri Lanka, 2021) Ruchikala, R.M.; Withanage, N.S.; Vithanachchi, J.Silica used as active reinforcing filler to improve high abrasion resistance in Rubber. In this study, the effect of four different silica grades (silica MP BET 161-190, silica powder newsil micro peral, silica 355GR and silica BET higher grade) on the abrasion resistance and other properties of the shoe sole have been studied. In this study type of silica grades was changed while keeping all the other ingredients and their amounts constant. The abrasion resistance was determined using DIN 53516 test method and the hardness, specific gravity, tensile strength and elongation at break were determined by following the respective ISO and ASTM standards. The results of the study showed that all four silica grades incorporated shoe soles have achieved acceptable abrasion resistance values. Achieved abrasion resistance value for shoe sole is maximum 350mm3. However, silica MP BET 161-190 has 289 mm3 which is also a quite higher abrasion resistance with a minimum loss of rubber in abrasion compared to other three silica grades. When considering the effect of silica grade on the physical properties of rubber compound, both silica MP BET 161-190 and 355GR grades showed acceptable values for all tested hardness, specific gravity, tensile strength and elongation at break of silica MP BET 161-190 grade incorporate sample were 48 IRHD, 1.088,17 MPa and 676% respectively. While silica 355GR incorporated sample were 51 IRHD, 17.1MPa and 631% respectively. However, both silica powder newsil micro peral and silica BET higher grade incorporated samples showed poor performance for the tested physical properties. Therefore, it can be concluded that, silica MP BET 161-190 is better performing as an active reinforcing filler with the highest abrasion resistance and a minimum loss of rubber in abrasion compared to other three silica grades. Keywords: Abrasion resistance; Physical properties; Shoe sole; Silica gradesItem Development of a Protocol to Reduce the Total Dissolved Solids in Effluent Treatment Plant Water(Uva Wellassa University of Sri Lanka, 2019-02) Abeywardhane, D.G.C.B.; Fernando, A.G.M.T.D.; Withanage, N.S.Physico-chemical analyses of effluent treatment plant water of activated carbon manufacturing factory indicate that it has high total dissolved solids. Main reason for this high total dissolved solids is the availability of high amount of sulfate ions in effluent treatment plant water. Therefore, the aims of this study were to develop an effective method to reduce the total dissolved solids level in effluent treatment plant water and to release quality water to the environment after improving the effluent treatment process. The experiment was conducted in five stages. In first stage, 4 g of calcium hydroxide was added to precipitate calcium sulfate. In second stage, 1 g of calcium hydroxide and 1 g of aluminum were added to form ettringite and in third stage, the decant was passed through 500 g of sand filter. In fourth stage, filtrate was passed through 300 g of resin and finally pH was adjusted using carbon dioxide. The addition of lime and aluminum in second stage combines with soluble sulfate and forms calcium-aluminum-sulfate compound known as ettringite. The formation of ettringite can remove other types of heavy metals also. Quality parameters of water were determined by using MYRON L- Ultra meter II- 4P II, Eco Testr pH 2 and nephelometry method of sulfate determination. The results showed that the initial total dissolved solids level of 8900 ppm in effluent treatment plant water could be reduced to 2500 ppm. It can be concluded that this developed treatment process is capable of reducing the initial total dissolved solids in effluent treatment by 70%.Item Development of activated carbon included natural rubber latex pillow(Uva Wellassa University of Sri Lanka, 2015) Bulathsinghala, B.A.D.U.P.; Withanage, N.S.; Samaraweera, U.H.T.P.Latex is a milky white liquid tapped from the trunks of rubber trees (Hevea brasiliensis) and then combined with water to create a thick suspension. In manufacturing natural latex foam rubber, the latex suspension is whipped to a froth and poured into carousel moulds, onto a conveyor, or into sheets and then heated to the point of vulcanization (Polyurethane Foam Association, 2000). Activated carbon(AC) is a non-graphite form of carbon which could be produced from any carbonaceous material. AC manufactured from coconut shell is considered superior to those obtained from other sources mainly because of small macro pores structure which renders it more effective for the adsorption of gas/vapour and for the removal of colour and odour of compounds (Coconut Development Board, 2013). AC has numerous applications due to its higher adsorption property. Thus it is capable to adsorbing volatile organic compounds which are also air pollutant in the atmosphere. The incorporation of activated carbon into natural rubber latex foam pillow can provi de volatile organic compounds adsorption property apart from its cushioning effect. Many volatile organic compounds are toxic, posing a high risk to human health as a result of their widespread use and occurrence in laboratory, home and also workplace envi ronments (Magureanu, Mandache, Eloy, Gaigneaux and Parvulescu, 2005). Therefore natural rubber latex foam pillow currently available in Sri Lankan market can be successfully value added by incorporating coconut shell based activated carbon to get the similar cushioning effects together with air purification ability upto a certain level . Methodology The current study was carried out at Richard Pieris Natural Foam (RPNF) Ltd, Malwana, Biyagama. Laboratory tests were done at RPNF, Richard Pieris Company plc and Bureau Veritas Consumer Product Services Sri Lanka (Pvt) Ltd laboratories. Two experimental trials with different treatments were conducted during this study. Experimental trial I was carried out to find out the appropriate activated carbon level suitable for the natural rubber latex foam pillow. It was compromised with eight treatment levels having 0% to 7% activated carbon levels with other compounding ingredients as different treatments levels. Each treatment was replicated 3 times. Experimental trial II was done in order to find the air purification ability with respect to acetone adsorption capacity. In experiment II, both the control which has 0% activated carbon and 2% of AC treated pillow were used to investigate the acetone (a VOC) adsorption capacity. Both treatments were replicated 3 times. Complete Randomized Design (CRD) was conducted and data obtained from both physical properties tests and acetone adsorption capacity was analyzed using analysis of variance (ANOVA) procedure of Minitab 16. Mean comparison of treatments were done using the tukey’s test. Results and Discussion According to the physical properties evaluation (Hardness, compression set, density and tensile strength) the formulation with 2% of activated carbon has given a desirable physical structure and selected in experiment trial I. Based on the data analysis of hardness, there is significant difference (P<0.05) between control (currently manufacturing latex pillow without AC) and the different treatment levels whereas no significant difference between the Control and 2% of AC treatment. Therefore similar hardness can be obtained by incorporating 2% AC into the present latex pillow formulation. According to the results of compression set value, it is been observed that there is no significant difference between 2%, 3% of AC treatments and control. Whereas more economical benefit through the lower material cost can be obtained by incorporating 2% AC. As a rubber material is compressed over time, it loses its ability to return to its original thickness. This loss of resiliency may reduce the capability of a cushioning pad to perform over a long period of time (Compression Set of Elastomeric Materials, 2014). Therefore lower compression set value is better for the cushioning materials. However density and tensile strength do not show the significant difference in all the treatments. Generally, acceptable tensile strengths are above 0.006895 MPa depending to some extent on the final application of the flexible foam. There are some cases where lower tensile strength foams may be used, but it is generally advisable to use foams that have a tensile strength of at least 0.006895 MPa (Polyurethane Foam Association, 1994). In this study it shows that tensile strength for all the treatment levels have values which are more than the acceptable value. In experimental trial II, activated carbon treated pillow was selected due to its high acetone adsorption capacity.Item Development of Natural Rubber (NR) and Ethylene-Propylene-Diene-Monomer (EPDM) Rubber Blend for Tie Down Strap Compound(Uva Wellassa University of Sri Lanka, 2013) Karunarathna, A.K.S.; Withanage, N.S.; Withanachchi, A.J.M.Tarpaulins or tarps are basically heavy duty waterproof covers that are used to secure loads in pickup trucks, tractors, dump trucks, etc. preventing from any untoward incidences happening during transportation. The tarps for trucks come with hooks or tie down straps to attach them securely to the vehicle body. These tie down straps are mainly used to hold tarps securely in place by providing high tensile strength and constant tension. Tie down strap is made out of natural rubber (NR), ethylene propylene diene monomer rubber (EPDM) or a combination of the both NR & EPDM by using cross-blending of two master batches method. Both NR and EPDM rubber have unique properties inherent to each material. Strap material selection is based on the climate they are used in. Natural rubber is ideal for cooler climates, as it will not crack and split in colder conditions. EPDM rubber was designed for warmer climates as it stands up better to extended sun exposure and hot UV rays (Anonymous, 2013).When concern the properties, NR will stretch further than EPDM rubber and will return to its normal non-stretched state quicker than EPDM rubber. To obtain the desired properties of both NR and EPDM, blends of the NR & EPDM are being used. The development of blends of NR and EPDM will deliver superior physical properties with the combination of excellent resistance to weathering of EPDM, in particular to attack by ozone (Rattanasupa, 2007). The addition of compatibilizer improves the compatibility of the NR/EPDM blends. It has been reported that graft copolymers widely used as compatibilizing agents, usually to enhance interfacial interaction in polymer blends, thus improving their mechanical properties (Arayapranee and Rempel, 2007). Based on above literature, a study was conducted to identify the most promising NR/EPDM blend ratio depend on cure characteristics and physical properties and to identify the effect of Methyl- methacrylate-butadiene-styrene (MBS) as a compatibilizer on NR/EPDM blend for tie down strap compound. Methodology The research study was carried out in a laboratory of Samson Compounds (Pvt) Ltd, Bataduwa, Galle. Complete randomized design (CRD) was used as the experiment design and the experiment was divided into two sub experiments as experiment 01 and experiment 02 aligning with the objectives. Total mixing time and the ingredients were different for each experiment but the blending procedure for both experiments was remained same. In experiment 01, the different blend ratios of NR/EPDM (N90, N80, N70, N60, N50, N40, N30, N20, N10) were prepared by mechanical blending and blend ratios were tested for cure characteristics, physical properties and thermal aging characteristics aged at 70°C for 22 h in respect of product specifications (Samson rubber products, 2012) of tie down strap. Replicates of hardness and tearing were three and replicates of tensile strength, elongation at break and tension set were arranged as four.Item Effect of Anti-transpirant in Sustaining Rubber Leaf Physiology Under Dry Climatic Condition(Uva Wellassa University of Sri Lanka, 2016) Rupasinghe, P.S.V.; Withanage, N.S.; Munasinghe, E.; Rodrigo, V.H.L.Protocols have been developed to expand the rubber (Hevea brasiliensis) cultivation to Dry and Intermediate Zones of Sri Lanka, where moisture stress is the major climatic constraint. Suitable adaptation techniques are still to be developed to endorse rubber cultivation under such sub-optimal conditions. In this context, introduction of anti¬transpirant has been renowned as an agro-management practice to resist crops with drought conditions. Therefore, present study was conducted to assess the benefits of anti¬transpirant application in sustaining leaf physiology of rubber plant under dry climatic condition. The experiment was conducted in Padiyathalawa GN Division in Ampara district during 13th May to 22" July, 2015. The experiment was randomly arranged as two factor factorial design in three blocks. Three concentration levels (0.3 mL/L, 0.45 mL/L and 0.6 mL/L) of anti-transpirant, Green Miracle were tested against three levels of application intervals (2, 3 and 4 weeks) and thus, there were nine treatment combinations over untreated control. Environmental parameters, namely, rainfall, maximum and minimum temperatures, solar radiation, relative humidity, wind speed and soil moisture content; physiological parameters namely, stomatal conductance, chlorophyll content, photosynthesis and relative water content; growth parameters, namely, plant diameter, plant height and total leaf count of the plants were recorded over the study period. A dry period was observed during r to 22nd July, 2015 with high temperature (23 °C to 34 °C), low RH (76% to 53%) and with very low rainfall. Rubber plants with the application of anti-transpirant at different concentrations and application intervals outer performed over the untreated control in terms of stomatal conductance, chlorophyll content, photosynthesis and total leaf count of the plant. Application of anti-transpirant with a concentration of 0.45 mL/L at 2 weeks interval contributed to a significant increase in stomatal conductance and chlorophyll content of leaves together with better results for photosynthesis rate, parameters of light response curve and relative water content over control. Application of anti-transpirant with a concentration of 0.6 mL/L at 2 weeks interval contributed to better results for studied growth parameters. Hence, the application of ,Green, Manti-transpirant would be a better attempt to expand the rubber Cultivation to non Traditional rubber growing areas of Sri Lanka, while sustaining the leafIg • physioIogy of rubber plant under dry climatic condition. Keywords: Anti-transpirent,Leaf physiological parameters, Moisture stress ,Item The Effect of Bis-(3-triethoxysilylpropyl)-Tetrasulfane and Polyethylene Glycol on the Properties of Natural Rubber/ Mica Composites(Uva Wellassa University of Sri Lanka, 2021) Edirisinghe, E.D.S.; Somarathna, Y.R.; Withanage, N.S.; Dhanukamalee, H.M.H.; Samarasinghe, I.H.K.; Siriwardena, S.The bis-(3-triethoxysilylpropyl)-tetrasulfane (Si69) is widely applied as a coupling agent to rubber- filler interactions in silica filled rubber composites. In this study, the effect of bis-(3- triethoxysilylpropyl)-tetrasulfane (Si69) and polyethylene glycol (PEG) on the properties of natural rubber (NR)/mica composites has been studied. The mica loading and the total weigh of Si69/PEG were kept constant at 30 phr and 2 phr, respectively. A composite free from Si69/PEG (SP00) was used as the control, while ratios of the above chemicals (Si69: PEG) were varied as 1:0, 0:1 and 1:1 in the other composites. These three systems were denoted SP10, SP01 and SP11, respectively. Curing characteristics, physico-mechanical properties and thermal degradation of NR/mica composites were investigated. The maximum cure time (Tc90) and scorch time (TS2) were exhibited in the SP10 compound. However, introduction of PEG into the system with Si69 in SP11 composite yield a reduction in Tc90 and TS2, which were comparable with the control (SP00). Maximum tensile strength and elongation at break were observed in Si69 treated NR/mica composite (SP10). This could be attributed to the improved rubber-filler interactions caused by incorporation of higher amounts of Si69 (2 phr). Further, the composite treated with both Si69 and PEG (SP11) with 1 phr each, has shown the second highest tensile strength among candidate composites. However, the enhanced moduli values at 100%, 300% and 500% elongation indicated better rubber-filler interactions in SP11 composite than SP10. The same reason may have resulted the highest hardness and resilience values in SP11 composite. The thermogravimetric analysis indicated that the application of Si69 and/or PEG have no significant impact on the thermal degradability of NR/mica composites. It was also found that SP01 exhibited the highest swelling ratio among all samples. Therefore, overall results indicated that PEG/Si69 treated system (SP11) could be employed more effectively than individual use of Si69 and PEG to optimize the cure characteristics, while improving the physico-mechancial properties of NR/mica composites. Keywords: Mica; Natural rubber composites; Polyethylene glycol; Coupling agent; Rubber-filler interactionsItem Effect of Carboxy Methyl Cellulose on Viscosity of NBR(Uva Wellassa University of Sri Lanka, 2019) Botheju, P.C.T.; Withanage, N.S.; Jayabodhi, P.Organic Sodium Carboxy Methyl Cellulose (CMC) is a water-soluble cellulose ether and macro molecule electrolyte. CMC is versatile in its ability to control rheology and viscosity of aqueous systems. CMC also has micro foam effect and it gives the deer skin property and smoothness to the glove surface. Therefore, the aim of this study is to examine the effect of CMC on viscosity of NBR. Solidified CMC samples were used in the experiment. CMC were mixed with cure pack. In the mixture, 65% of mixture was CMC and 23% of the mixture was cure pack. The remaining 12% was water. The mixture was added to the nitrile compounds which were prepared according to the same formulation by using different treatments such as T0-control treatment with no mixture, T1-115 g of mixture, T2-86.25 g of mixture, T3-57.5 g of mixture, T4-28.75 g of mixture. Each treatment was replicated three times. After 8 hours mixing time the viscosity of the compound was measured once in each 2 hours for 7 days. Viscosity was measured using RV viscometer using spindle 3 at 20 rpm. The total solid content of the all samples were adjusted after 12 hrs. The results of the study revealed that, the standard viscosity was given within 6 hours and there was a gradual increment of viscosity with the time initially and then the viscosity was stable. The tested treatments showed different stabilizing times and decreasing viscosities with the time. Further, in the control treatment, there was only a viscosity increment and there was no plateau development. Therefore, the viscosity of the compound has been affected and the mixing time could be decreased with the addition of CMC which will be more effective in rubber industry.Item Effect of Eco-friendly Growth Media on Survival Percentage of Tea [Camellia sinensis(L.) O. Kuntze] to Mitigate Short Term Drought at Nursery Level(Uva Wellassa University of Sri Lanka, 2018) Bandara, K.L.A.Y.D.; Bandara, S.N.; Withanage, N.S.; Jayasingha, H.A.S.L.Tea is generally considered to be a shallow-rooting plant, sensitive to the physical condition of the soil and thus growth media may help effectively mitigate shortterm drought conditions. Therefore, this study was conducted to study the effect of growing media on soil properties and survival percentage of tea cultivar TRI 2023 during short term drought period at Tea Research Institute, Ratnapura. Six treatment combinations having three growth media (charcoal, paddy husk and refused tea) and two different application methods (3 inches high growth medium layer applied to the bottom of the pot and growth medium incorporated into the soil) were used in pot experiment under protected house condition. Each treatment was replicated four times and CRD was used. Initially, soil moisture status of all treatments was adjusted to a saturation point and after that irrigation was not done for one month. Water runoff and percolation were inhibited using bottom closed pots and evapotranspiration (ET) was considered as the only method for soil moisture loss. ET (mm) was measured using weight difference method and survival percentage (%) was calculated in all 24 pots weekly for one month. Then the second irrigation was done again to saturation point and the study was continued for another month. The results revealed that, there were significant differences among six treatments for both tested parameters. Further, the lowest percentage weight difference (11.2695%) and the highest survival percentage (89.8%) were observed in charcoal incorporated into soil at 1:2 ratio during the study period. Therefore, charcoal incorporated into soil (1:2) can be effectively used as an eco-friendly growth medium as it increases the water retention facilitating more survival of potted plants of tea cultivar TRI 2023 in nurseries during short term drought period.Item Effect of Explant Source and Hormone Combinations on In –vitro Propagation of Different Genotypes of Gerbera (Gerbera jamesonii)(Uva Wellassa University of Sri Lanka, 2010) Weerasinghe, S.K.M.M.; Hearth, H.M.I.; Kaliyadasa, P.E.; Withanage, N.S.This research was carried out to study the effect of explant and hormone combinations on in-vitro propagation of different genotypes of Gerbera, in order to produce high quality, disease free planting materials for commercial cultivation. Experiments were conducted to select the best hormonal combinations among TDZ, IAA, 2,4-D and to select best calli and to find out the best hormonal combination to develop green calli. Treatments were replicated five times and allocated according to the complete randomized block design. In experiment one, leaf and capitulum of explants Ecco and Winter Queen varieties were cultured in MS media supplemented with different combinations of TDZ, IAA and 2,4-D. In experiment two, leaf and capitulum explants of the hybrid of Ecco and Winter Queen were treated with the selected best hormone combinations from experiment one. The selected, best dal from experiment one and two were transferred in to the multiplication media (MS with 0.5 mg/I BA, 0.5 mg/I Kinetin and 0.4 mg/I IAA) in experiment three, to find out the best hormone combinations to develop the desired green calli. Culture conditions for all experiments were maintained, at 26 ± 2 °C, 25% RH and 16 hour photoperiod. All experiments were designed using CRD with 5 replicates. In experiment one and two, the percentage of calli growth was recorded. In vitro propagation of variety Ecco and Winter Queen with capitulum explant can be combined with 0.5 mg/I IAA and 0.5 mg/I TDZ economically, as there was no significant difference (P<0.05) in percentage of calli growth and green calli development compared to 0.5 mg/I IAA and 1.0 mg/I TDZ. In hybrid, capitulum explant was not significantly succeeded (p<0.05) whereas leaf explant recorded the highest calli growth (85%) at p<0.05 with 1.0 mg/I 2,4-D. The best green calli growth in multiplication media was recorded in sixth weeks after establishment and no significant growth was observed thereafter. The results of above experiments revealed, that the hormone combinations of 0.5 mg/I TDZ and 0.5 mg/I IAA with capitulum explant in variety Ecco and Winter Queen and the leaf explant of hybrid with 1.0 mg/I 2,4-D can be successfully used in in-vitro propagation of Gerbera in commercial scale. Key words: IAA, TDZ, Capitulum, Multiplication, Calli growthItem Effect of Moisture Content on Quality of Vermicompost and Specific Earthworm (Periyonix excavatus) Population(Uva Wellassa University of Srilanka, 2011) Mihirangi, D.P.A.; Weerasooriya, J.D.; Withanage, N.S.Note: See the PDF Version The aim of the present agriculture practices is to be obtaining high yield using genetically modified, sterilized hybrid seed. The other side of modernization was degradation of fertile agricultural lands due to dependence on chemical fertilizer, pesticides and herbicides. Continuous use of those inputs has damaged the biodiversity. Vermicomposting is an ecofriendly, socially sound and economically viable technology to protect environment. Vermicompost contains not only worm castings, but also bedding materials and organic wastes at various stages of decomposition. Therefore, it provides high porosity, moisture content, aeration and water holding capacity. And also it has been shown to have higher level of organic carbon, total and available N, P, K and other micronutrients, microbial and enzyme activities and plant growth regulators. Therefore, it can be a good replacement to chemical fertilizer. Even though vermicomposting is an age old process, due to rapid changes in technology in present scenario it is essential to change such process with application of advanced technique available. The moisture content plays a significant role in the process of vermicomosting. Therefore the objective of this study was to evaluate the effect of moisture content on quality of vermicompost and Periyonix excavatus earthworm population.Item Effect of vulcanizing and antioxidant systems on aged tensile properties of MicrOptic gloves(Uva Wellassa University of Sri Lanka, 2015) Ekanayake, E.A.S.L.; Withanage, N.S.; Jayabodhi, P.A.P.N.MicrOptic glove is a powder free surgical glove which is made out from the natural rubber latex. Thin nature of MicrOptic glove facilitate exceptional dexterity and tactile sensitivity and at the same time outstanding strength and barrier protection (Ansell Medical GBU, 2014).Aged tensile properties of the glove cannot be maintained in a stable level due to the thin nature of the glove. Natural rubber vulcanizates can be given adequate heat-aging resistance by a suitable choice of vulcanization and by using ammine or phenolic antioxidants (Morton, 2010). The study was conducted to disclose the effect of vulcanizing system, antioxidant system and their combined effect on aged tensile properties of MicrOptic glove. Materials and Methodology The study was carried out centralizing to Ansell Lanka (Pvt) Ltd, EPZ - Biyagama. Aged tensile test was done at Quality Control (QA) laboratory at Ansell Lanka (Pvt) Ltd. Nine trials with different treatments were conducted during this study. 0.5 pphr elementary sulphur(V1), 0.25 pphr elementary sulphur with 0.5 pphr sulphur donor compound (V2) and 0.25 pphr elementary sulphur with 1.0 pphr sulphur donor compound (V3) were utilized as three different vulcanizing systems in MicrOptic formula. 1.5 pphr primary antioxidant (A1), 1.0 pphr primary antioxidant with 0.25 pphr secondary antioxidant (A2) and 1.0 pphr primary antioxidant with 0.5 pphr secondary antioxidant (A3) were utilized as three different antioxidant systems in MicrOptic formula. All the dispersions of vulcanizing agents and antioxidants were made by using laboratory scale ball mill. Nine glove compounds with three replicates were produced according to MicrOptic glove formula except the vulcanizing agent and antioxidant system. Vulcanizing agents and antioxidant were added according to the treatment combinations.The compounded latex was kept for 36 hours to obtain optimum degree of crosslinks. 65 - 75 % toluene swelling index (TSI) was used as optimum degree of crosslinks.Sample gloves are made under laboratory conditions.Clean former was heated up to 65 ºC by using an oven and then former was dipped in a MicrOptic glove coagulant solution at 65 ºC with constant time of 22 seconds. Coagulant solution was dried by using an oven and heated up to 55 ºC. Then former was dipped in latex solution with constant time of 23 seconds and bead of the glove made by manually. After that gloves were leached in hot water (70 ºC) for 2 minute. Finally, formers with gloves were cured at 120 ºC for 35 minutes. Aged tensile properties (ATP) such as force at break (FB), elongation at break (EB) and 500 % modulus (MOD) were measured according to the BS EN 455-2:2000 standards. Factor factorial in complete randomized design was conducted and data obtained from aged tensile properties were subjected to analysis of variance (ANOVA) using the general linear model procedure of MINITAB 16. Significant means of treatments were separated using the least significant difference (LSD) (P< 0.05) test. Results and Discussion The study revealed that the effect of vulcanizing system on force at break, elongatio n at break and 500 % modulus were significant (p < 0.05). Also combine effect of vulcanizing system and antioxidant system on force at break, elongation at break and 500 % modulus were significant(p < 0.05).Further, this study disclosed, the effect of antioxidant system on elongation at break was significant (p < 0.05). However, effect of antioxidant system on force at break and 500 % modulus were not significant at 5% significant level.Item Estimation of Water Footprint of Black Tea Production: A Case Study in Madulsima Plantations PLC, Badulla, Sri Lanka(Uva Wellassa University of Sri Lanka, 2021) Dayarathna, B.D.S.; Aberathna, W.S.S.L.; Withanage, N.S.; Kahandage, K.P.M.Water is an economic commodity as the availability of clean fresh water in short supply. Most water resource experts now agrees that inadequate water management , rather water shortage, is the primary cause of water conflicts. Meanwhile the virtual water concept has become popular in estimating the amount of water used in the production of goods or services, linking framework to find potential solutions and contributing to improved water resource management. Water footprint is a tool to calculate the amount of water that is consumed and polluted in all stages of a production process. Generally, three types of water are considered in water footprint calculations; green water, blue water and grey water. The present study was conducted to estimate the water footprint of black tea production at two tea estates of Madulsima Plantations PLC. Green water footprint of tea was calculated using CROPWAT 8.0 model. Blue and grey water footprint of black tea were calculated following the guidelines in the Water Footprint Assessment Manual. The results revealed that, the virtual water content of black tea production of Madulsima Plantations PLC was 4270.69 m3/ ton / year. Further the green water footprint for evapotranspiration of tea was 1090.7 mm / year. The total green water content in black tea of the studied two estates was 3227.68 m3 / ton and it is three times less than that of the average value of Sri Lanka while much less than those of China, India, and Kenya as available in the scientific literature. Further the blue water footprint of black tea production of these estates was 1.23 m3 / ton and it is negligible when compared with China and India. The grey water footprint of tea cultivation practices in these estates was 1041.78 m3 / ton and it is also less than those average values of the Sri Lanka and China. However, the grey water footprint of the studied two estates can be potentially reduced by incorporating organic cultivation concept in the long run. Keywords: Black tea production process; CROPWAT 8.0 model; Cultivation practices; Virtual water content; Water Footprint Assessment ManualItem Evaluation of Different Methods of Reducing Night Temperature in Seed Potato (Solanum tuberosunt L.) Production in Simplified Nutrient Film Technique(Uva Wellassa University of Sri Lanka, 2018) Kanchana, H.L.K.; Jayamanne, J.M.D.D.E.; Ranawana, S.R.W.M.C.J.K.; Withanage, N.S.Potato is a starchy, tuberous crop belongs to the family Solanaceae. Although potato is the 4thlargest food crop and the staple food in some countries, potato is commercially grown only in Nuwara-Eliya, Badulla, Jaffna and Puttalam districts in Sri Lanka. However, Seed potato is mainly produced in Nuwara-Eliya due to favourable weather conditions in this area especially low night temperature. Seed potato production in Banadarawela is relatively low because of the high temperature compared to Nuwara-Eliya. Tuberization is promoted under low night temperatures. Because of that high night temperature in Bandarawela may reduce tuberization. Thus, reducing night temperature by different methods may help to increase the seed potato production. The current study was conducted under controlled environmental conditions using Simplified Nutrient Film Technique (SNFT) to identify the best method to reduce night temperature for seed potato production in Bandarawela. Five night temperature controlling methods (T1 -Control, T2-Mini exhaust fans in bins, T3-Fan pad method combined with mini exhaust fans in bins, T4-Fan pad, T5-Nutrient cooling) with three replicates were installed and plant performances were measured once a week. Key yield determining parameter, number of tubers (25) was significantly higher in SNFT with T3 compared to other treatments (T1-13, T2-12, T4-19, T5-14). Mean values of plant height (cm), stem height (cm}, number of stolons, root volume (cm3) and stolon volume (cm3) were significantly higher in T3 (126.8, 102.6, 15, 14.3, 10.3, respectively) compared to control (105.9,76.7,10,12.4, 6.4, respectively). Moreover, T3 reduced the night temperature by approximately 1-2 °C. Therefore, fan pad method combined with mini exhaust fans in bins method is the most suitable method to reduce night temperature for seed potato production in Bandarawela region.Item Factors affecting the level of effectiveness of dryers used in Sri Lankan tea manufacturing(Uva Wellassa University of Sri Lanka, 2015) Ruwanka, W.K.T.; Weerawansha, A.N.R.; Withanage, N.S.; Pathmasiri, M.M.R.Tea production is basically a drying process of freshly harvested green tea leaves, reducing its moisture content from about 75-83% down to 3%. In black tea manufacturing tea undergoes mainly withering, rolling, fermenting, drying, grading and packaging processing steps. Sri Lanka mainly produces tea by the Orthodox technology. Drying is the most expensive process in the manufacture of tea (http://www.biriz.biz/cay/TeaSector2002). The capital investment on dryers is also the highest among the different processing machines. There are three different types of tea dryers up to now namely ECP (Endless Chain Pressure), FBD (Fluidized Bed Dryer) and combination dryers. ECP dryer has been used in tea industry since 1907 and fluidized bed dryer was first developed for tea in Sri Lanka in 1974 (Temple S.J., 2000). Tea dryers have its defined output as rated output. But normally dryer machines give lower output (actual output) than rated output. There may be several reasons affecting for dryer output deviation from rated output. Ultimately this would lead to poor production and high cost of production to the tea factories. Main objective is to find out the factors affecting for deviation of actual dryer output from rated dryer output in different types of tea dryers. Materials and Methodology Effectiveness of three types of tea dryers was taken as dependent variable. Effectiveness of tea dryers can be measured as the ratio between actual output and rated output. It will be finally taken as a percentage value. As independent variables four factors have been selected as moisture content of withered leaves (wither percentage %), age of three types of dryers (Years), moisture of firewood used for drying (firewood moisture) and dhool percentage taken after roll breaking process (first, second and third dhool percentage). The sampling frame was 37 tea dryers representing three manufacturing regions in Sri Lanka (Up country, Mid country and Low country). There were 17 ECP dryers, 15 FBD dryers and 5 combination dryers in the sample. The data were collected for recent three months time period and average values were taken finally. For the analysis descriptive, correlation and simple linear regression was used. Results and Discussion According to descriptive statistics mean effectiveness of ECP, FBD and combination dryers were 85.88%, 89.83%, 91.53% respectively.Item Firewood energy utilization in different dryers used in Tea processing(Uva Wellassa University of Sri Lanka, 2015) Chathurangi, N.H.K.; Withanage, N.S.; Pathmasiri, M.M.R.Tea industry is one of the most key important drives in Sri Lankan economy. Sri Lanka Sustainable Energy Authority is one of the important government institutions for energy management and enhancing awareness and creating technical capacity on energy conservation in Sri Lanka. Tea industry utilizes both electrical and thermal energy for its processing. The tea factories pre- dominantly use fuel wood to meet their thermal energy needs, in the drying process, which is the major transformation process in the tea industry. The lack of researchers on the energy utilization of different dryers used in Sri Lankan tea industry and different types of dryers are used depending on the production capacity of the tea factory. The objectives of the research are to find out firewood energy utilization of different dryers and performance of different dryers in Sri Lanka. Materials and methodology The research was carried out to Sustainable Energy Authority during the period from April to August 2014. Specific thermal energy utilization (MJ/kg) was used to measure the level of firewood consumption for dryers and it was tested for different dryers, location and combustion technology. Two factor factorial design was implemented as the experimental design where dryer type and combustion technology were taken in to consideration .There are three types of dryer commonly used in tea drying such as, conventional endless chain pressure type dryer (ECP), Fluidized bed drier (FBD), and combination drier which works on a combination of ECP and FBD principles .There are two types of combustion technologies used for tea drying such as, Boilers and furnace. Primary data were collected from factory officers by providing the structural questionnaires. Secondary data were also collected from the annual reports of Sri Lanka Sustainable Energy Authority and factory reports of different tea factories. Collected sample was surveyed based on the factory records during 2012 to 2013 to gather necessary information. Factory observations were also was carried out to confirm the accuracy of data that were collected by the interviews of factory officers and Factory managers. Minitab 16 Statistical Software was used for both descriptive and interferential statistics. ANOVA General linear model was used to analyze the variance of dryer output in relation to dryer types and combustion technology. Collected data were analyzed using descriptive statistical methods. Descriptive statistics were graphical explained with using of Microsoft Excel and Minitab software. Pearson correlation was used to determine the association of consumption of firewood and total production. The relationship of firewood consumption and total production were analyzed by using simple regression technique. Results and Discussion According to descriptive statistics, firewood Energy Source was highly used in tea processing. The result revealed that, 19% firewood and saw dust, 8% firewood and furnace oil, only 3% of firewood and coconut shell was also used. Jungle wood was highly used in tea processing. The results showed that 36% rubber firewood and only 19% rubber and jungle wood were also reported. The low country and mid country tea factories use only firewood and saw dust. But up country tea factories use different types of energy sources. Up country tea factories mainly use Fluidized Bed dryers and mid country and low country highly use Endless Chain Pressure dryers. Low country and up country mainly trended in small scale production and mid country highly trended in large scale production. In mid country, it is available large, medium and low price firewood. But in up country and low country, it is available only large and medium price fire wood. The Endless Chain Pressure dryer was the highly used dryer type.it was revealed that, 28% of Fluidized Bed dryers and only 25% of combination dryers were also used in tea processing. Endless Chain Pressure dryers had the dryer capacity of 180-280 kg/hr, Fluidized Bed dryers had 280-500 kg/hr and Combination dryers had 250-450 kg/hr capacity. Endless Chain pressure Dryers are easy to be maintained than others. Endless Chain Pressure dryers were mainly used in small scale production, Fluidized Bed dryer and Combination dryers were highly used in large scale production in tea factories. The furnace combustion technology was highly used in tea processing. 61% furnace and only 39 % of boilers were reported. Majority of tea factories in small scale production use furnace and tea factories in large scale production use boilers. Majority of low country and mid country tea factories use furnaces and up country tea factories use boilers and prominently Endless Chain Pressure dryers utilize the energy of furnace and Fluidized Bed dryers use the energy of boilers. When consider the Regression output, P value 0.000 of the model suggests that at 5% significant level, firewood consumption is significant in relation to the dryer made tea production. R – Square was recorded as 49.3 % and it implies that 49.3% of the firewood consumption is explained by the made tea while the 50.7% is explained by unexplained variables.Item Household Level impacts of Uma Oya Development Project(Uva Wellassa University of Sri Lanka, 2018) Bandara, K.M.S.; Dharmadasa, R.A.P.I.S.; Herath, H.M.S.K.; Withanage, N.S.Negative Effects on the community around Uma Oya Multi-Development project is a debating topic at present scenario. Therefore, the purpose of this study is to find out the specific socio, economic and environmental factors affecting the impact of Uma Oya Multi-Development Project at household level in one of the most affected areas, Bandarawela Divisional Secretariat. A total sample of 152 households was selected for the study. 76 households from the construction area were used to assess the real impact of the ongoing constructions. The remaining 76 households from the non-construction area were considered to assess the dissipating effects to nearby areas. The performed methods of analysis included frequency distribution, descriptive analysis, Mann-Whitney test and logistic regression. The findings revealed that distance to the construction site and selected areas for the study have a negative relationship with the household level impact. Further, the results suggest that the project has a negative impact on residential area of the households and the residences, water sources, and land extent of crops. The impact on non-construction areas and construction areas was compared through Mann-Whitney tests and the results revealed that there is a significant difference between non-construction areas and construction with respect to the farming status, water scarcity, damage to the the households, damage to the land, degree of crop losses and government assistance. It can be finally concluded that there are significant differences between tested construction areas and non-construction areas on the impact of Uma Oya Multi-Development Project in Bandarawela Divisional Secretariat.Item Impact of a Modified Sifting Process Model in Pure Orthodox Black Tea Manufacturing for Higher Profitability(Uva Wellassa University of Sri Lanka, 2012) Rajapaksha, R.M.P.; Withanage, N.S.; Galahitiyawa, G.L.C.Tea is one of the most important cash crops in the world and it plays a very significant role in the Sri Lankan economy too. As a food beverage, tea is second only to water. Sri Lankan black tea is world famous as quality tea. But manufacturers try to increase the production to gain more profits without considering the quality. It will badly affect to the image of Ceylon black tea and our export market will definitely be affected. There fore, there is need to develop the current tea manufacturing process to earn more profits while increasing the quality of the end product, Sifting process is a cost sensitive step among the five main steps (withering, rolling, fermentation, drying and sifting) in the black tea manufacturing process (Zoyza, 2008). It demands more workers and electricity, leading to increase in the cost of production (Energy Audit Report of St. Joachim Tea Factory, 2002). But it is a very critical and valuable step as it separates the different tea grades which are produced to cater the market requirements. So the siring process directly affects the generation of profits in a factory through higher Net Sale Average (NSA) and lower cost of production. Therefore, studying the basic steps o£ factory current siring process will show the right direction for the development of modified sifting process model without harming the end product (tea grades) of tea manufacturing (Annual Repon, 2011). The main objective of this research was to check the impact of the Modified sifting process mode I in pure orthodox black tea manufacturing for higher profits in the factory through increasing the NSA of the tea grades and reducing cost of production by saving worker, energy and time,