MERCon - 2021

Permanent URI for this collectionhttp://192.248.9.226/handle/123/18493

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item: Conference-Full-text
Atmospheric cold plasma to improve printability of polyethylene terephthalate
(IEEE, 2021-07) Sandanuwan, T; Hendeniya, N; Attygalle, D; Amarasinghe, DAS; Weragoda, SC; Samarasekara, AMPB; ; Hemachandra, K; Adhikariwatte, W; Rathnayake, M
Though paper is still the most common substrate in the printing industry, polymeric substrates are becoming common by the day. Commercially available polymers such as polyethylene terephthalate (PET), polyvinyl chloride (PVC) and polypropylene (PP) surfaces have lower density of polar functional groups. Thus, the adhesion characteristics of these materials are naturally poor. Consequently, producing a quality print on such polymer substrates has become a challenge. Hence, surface modification has become a necessity for such surfaces. This study investigates the technical viability of cold plasma-based surface treatment technologies on polymeric materials. The effect of plasma pre-treatment, on the printability of PET substrates, was studied. The surfaces of these polymer substrates were subjected to different cold plasma treatments, using 80% N2 and 20% O2 as feed gas. The study covers the effect of the plasma dose and the plasma intensity on the printability and the degree of surface modification. The study determined the optimum plasma conditions for quality and durable prints.
item: Conference-Full-text
Atmospheric pressure plasma treatment as a cost-effective and eco-friendly pre-treatment method to enhance seed perfomance in germination and early seedling growth
(IEEE, 2021-07) Hendeniya, N; Sandanuwan, T; Amarasinghe, DAS; Attygalle, D; Weragoda, S; Ranaweera, B; Rathnayake, K; Lalanka, M; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Novel methods of improving the seed quality have gained a lot of attention recently, cold atmospheric pressure plasma being one of the most promising methods. The effects of cold atmospheric pressure plasma treatment of chili - MI 2 (Capsicum annuum L.) and snake gourd - MI short (Trichosanthes cucumerina) seeds have been compared with a conventional fungicide seed coating and a biological coating treatment. The plasma exposure times used were 4min, 6min and 10min. Cold atmospheric pressure plasma treatment has shown improved effects on seed germination for both Capsicum annuum L. and Trichosanthes cucumerina seeds. Both seed types showed the best germination results under 6 min treatment while displaying the best Seed Vigor Index through 4 min plasma treatment. Compared with the coating treatments, cold atmospheric pressure plasma has shown a significant stimulation in seed germination and early growth.
item: Conference-Full-text
Effects of current density on the solder wettability of nickel electrodeposited ni20cr alloy
(IEEE, 2021-07) Kumarasiri, A; Herath, HS; Amarasinghe, DAS; Attygalle, D; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Nickel-chromium alloys are in high demand in the electrical industry, as they have some favorable electrical properties. The formation of a thin chromium oxide layer on the alloy surface protects the alloy from further oxidation. The passivation layer formation is almost instantaneous when exposed to the ambient atmosphere. It prevents the strong bonding between the solder and the substrate due to the alteration of the substrate's surface energy by the passivation layer. Poor solderability could cause short-circuiting and resistance variations in electrical devices. This paper reviews the effect on solderability due to the passive layer formation and proposes solutions to overcome the problems caused by this layer. The introduction of solder-compatible metal layers such as Ni onto the substrate surface is a way to overcome this. However, solder-compatible metals such as Ni cannot be introduced with conventional electroplating baths due to the alloy's passive behavior. Therefore, a breakdown of the passivity is required before the nickel coating. A three-bath electrodeposition strategy comprising; pre-cleaning, activation, and electroplating, were used to achieve the task. The study examines the dependency of solder wettability on the current density, using an in-house fabricated contact-angle measuring device and analytical software.
item: Conference-Full-text
Individualization of nanofibrillated cellulose from Sri Lankan rice straw: structural characteristics and thermal properties
(IEEE, 2021-07) Ratnakumar, A; Samarasekara, AMPB; Amarasinghe, DAS; Karunanayake, L; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Rice straw is the agricultural production residue which is considered as an agricultural waste. Though it is utilized in various ways, there is a greater possibility for value addition by disintegrating nanofibrillated cellulose from this commercially underutilized waste material. In this study, nanofibrillated cellulose (NFC) was individualized from locally available rice straw variety Murunkan via chemo-mechanical treatments. Firstly, cellulose fibers were extracted from rice straw via a set of chemical processes. Then using high intensity ultrasonication (HIUS) treatment acquired cellulose fibers were individualized into nanofibrillated cellulose. Structural, morphological and thermal behavior of NFC throughout the chemo-mechanical processes were studied. FTIR analysis confirmed that the chemical composition of nanofibrillated cellulose was mainly cellulose where amorphous natured hemicellulose and lignin were effectively removed during chemical processes. From the set of chemical processes, Murunkan variety yielded around 34 per cent cellulose fibers. Out of these cellulose fibers around 17 per cent NFC was individualized via the HIUS treatment. Microscopy study showed that the diameters of the extracted NFC ranged between 100 to 200 nm. Findings of this study will not only add value to the rice straw but also embrace sustainable transition to a bioeconomy in the country.
item: Conference-Full-text
Linear and non linear creep modeling of talc filled peek composite
(IEEE, 2021-07) Janith, GI; Amarasinghe, DAS; Attygalle, D; Weragoda, VSC; Samarasekara, AMPB; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
The creep compliance of a viscoelastic material is a crucial material parameter that controls the time dependent creep. Viscoelastic materials and their composites are being widely used in electronic and structural components where strain response of such a material is of great concern. Linear viscoelastic models such as the generalized kelvin Voigt model is widely used to model the linear creep behavior. Poly ether-ether ketone is a semi crystalline polymer and in this study a PEEK composite filled with talcum is being used which also consists of a semi crystalline polymer matrix. Such semi crystalline matrixes are known to bring forth nonlinear viscoelastic properties. In this study we model the linear creep behavior and the stress dependent nonlinearity of the above-mentioned composite.
item: Conference-Full-text
Microfibrillated cellulose fabrication and characterization from sri lankan rice straw: a comparison between traditional and hybrid variety
(IEEE, 2021-07) Ratnakumar, A; Samarasekara, AMPB; Amarasinghe, DAS; Karunanayake, L; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Rice is one of the major cereal crops cultivated globally. In the recent past, rice straw has gained momentum as a source of cellulose. However, it is notable that rice straw generated from rice cultivation has less or no commercial value. In this study, microfibrillated cellulose (MFC) was extracted from Sri Lankan traditional rice straw variety Pachaperumal and hybrid variety BG352 in two distinct stages. Initially, a series of chemical treatment methods that includes removal of wax and oil, lignin, hemicellulose and silica was employed to extract cellulose fibers from the aforementioned rice straw varieties. Then, using high-intensity ultrasonication (HIUS) process microfibrillated cellulose (MFC) was isolated from the obtained chemically extracted cellulose fibers. FTIR analysis validated that the chemical composition of MFC from both varieties were mainly cellulose where hemicelluloses and lignin were successfully removed during the set of chemical processes. Study revealed that around 34 per cent cellulose was extracted from Pachaperumal and around 25 per cent cellulose was extracted from BG352. Out of these chemically extracted cellulose fibers around 16 per cent of MFC was disintegrated from Pachaperumal and around 9 per cent from BG352 via HIUS process. SEM analysis showed that the diameters of the MFC were in 200 to 300 nanometer range Results indicated that traditional variety yielded high amount of MFC than technically modified variety via the efficient multi-step treatment process with potential industrial applications.
item: Conference-Full-text
Modeling of laser assisted thermal reduction of graphene oxide
(IEEE, 2021-07) Rajapakshe, VS; Warnakulasooriya, WMDS; Amarasinghe, DAS; Attygalle, D; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
A computational model to predict the degree of reduction of graphene oxide by using laser irradiation was developed. 3-Dimensional thermal distribution was modeled using heat conduction equation and computational modeling was done using COMSOL Multiphysics software package. Mathematical model for reaction kinetics was carried out considering Lerf and Klinowski model of graphene oxide and thermal profile of graphene oxide, which predicts the oxygen percentage distribution along the surface and depth after laser irradiation. Combinations of laser wavelength and laser powers were identified that are feasible for reducing graphene oxide.
item: Conference-Full-text
Moisture transportation in polyester fabrics by plasma printed wicking channels
(IEEE, 2021-07) Gunarathna, RNP; Sandanuwan, T; Amarasinghe, DAS; Attygalle, D; Weragoda, SC; Hendeniya, N; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
By dissipating the absorbed moisture on clothes quickly, the wearer's comfortability can be improved. Wicking plays a vital role in transporting sweat away through the fabric from the generation areas of the body. Usually, this transportation is an undirected random process. It transports moisture in all possible directions, making large wet patches on the cloths, and these could lead to the wearer's discomfort. This paper reports a method to transport moisture away through predefined paths to predefined locations on weft knitted polyester fabric. The moisture transportation paths were printed on the fabric using a dielectric barrier discharge plasma gun. The results show the effectiveness of the proposed channel printing process for moisture management on the clothing.
item: Conference-Full-text
Process optimization of microfibrillated cellulose extraction from cotton waste using response surface methodology
(IEEE, 2021-07) Jayasinghe, JMR; Ratnakumar, A; Samarasekara, AMPB; Amarasinghe, DAS; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
Cotton is a natural staple fiber that mostly consists of cellulose compared to wood. The major economic value of cotton is in textile industry. Over the recent past years the demand for cotton consumption has increased significantly than its production. In textile manufacturing, cotton is blended with various other synthetic fibers such as polyester, nylon and lycra to obtain the desired properties. Though fabric recycling methods are available for pre-consumer garment waste, the processes are quite complicated in actual practice. In this work Microcrystalline Cellulose (MCC) extracted from cotton fabric waste was converted into Microfibrillated Cellulose (MFC) using acid hydrolysis method. However, the major challenge in using acid hydrolysis method is the low amount of yield. Three experimental factors that includes; acid concentration, hydrolysis time and temperature show the highest effect in yield and quality of MFC. Therefore, this experiment was designed to optimize the effect of these three independent factors on yield (%) and width (nm) of MFC. Response surface methodology was adapted to design the experiment and ANOVA statistical test results were used to determine the significant effect of those listed parameters on acid hydrolysis.

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Browsing MERCon - 2021 by Author "Amarasinghe, DAS"