ISAMA - 2023
Permanent URI for this collectionhttp://192.248.9.226/handle/123/22083
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- item: Conference-AbstractInternational Symposium on Advanced Materials and their Applications 2023. (PreText)(Department of Materials Science and Engineering, University of Moratuwa., 2023-12-14) Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, K
- item: Conference-AbstractMesoporous Graphene Oxide for High-Performance Supercapacitor Electrodes(Department of Materials Science and Engineering, University of Moratuwa., 2023-12-14) Amarathunga, AAS; Sitinamaluwa, HS; Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, KThis study focuses on the development of a high-performance supercapacitor electrode material with the specific emphasis on synthesizing mesoporous activated graphene oxide (AGO) derived from Sri Lankan vein graphite. A simple and cost-effective chemical synthesis route is employed to synthesize the mesoporous AGO, resulting in a material with a notable specific surface area over 700 m2g-1, as determined by Brunauer-Emmett-Teller (BET) analysis. The AGO-based electrode is fabricated using a slurry-coating method, incorporating Carbon black as the conductive additive and PTFE as the binder. Optimization of the electrode's performance is carried out with careful consideration of the maximum AGO loading. The electrochemical evaluation of the fabricated electrodes is conducted utilizing a three-electrode configuration using a Ag-AgCl reference electrode and a Pt counter electrode. Remarkably, an enhanced specific capacitance over 500 Fg-1 is achieved in a 1M HCl electrolyte, representing one of the highest reported values for AGO-based electrodes to date. The observed high capacitance is attributed to the unique combination of a high specific surface area, a three-dimensional mesoporous structure characterized by well-connected pores, and efficient ion and electron transport within the electrode, as confirmed by Electrochemical Impedance Spectroscopy analysis. AGO's outstanding performance positions it as a promising material for future energy storage applications, including electric vehicles and renewable energy systems.
- item: Conference-AbstractBismuth chalcohalides for optoelectronic applications(Department of Materials Science and Engineering, University of Moratuwa., 2023-12-14) Jayawardane, JTST; Sewvandi, GA; Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, KBi-based halide perovskites are an interesting class of material because of their rich structural diversity and the ability to exist in a wide range of coordination geometries (from cluster to 1D, 2D, or even 3D) makes them particularly useful for designing novel compounds for optoelectronic applications. Bismuth halides such as BiI3, A3Bi2I9 (where A is Cs+ or CH3NH3+), chalcogenides (Bi2S3, Bi2Se3), and chalcohalides (BiSI, BiSeI, BiSI5,Bi2Te2Br,(AlCl4)6), exhibit interesting electrical, magnetic, and optical properties. In this investigation, we report electronic structure, connection to the crystal geometry, density of states and band structure of BiSeI, BiSeBr, Bi3Se4Br and BiSI Bismuth chalcohalides as potential optoelectronic materials. All calculations are performed within the framework of density functional theory using the plane-wave pseudopotential method as implemented in the Vienna Ab-initio Simulation Package (VASP). Crystal structures of the bismuth chalcohalides two distinct crystal structures can be identified. BiSeBr, BiSeI, BiSI possess an orthorhombic structure (space group Pmmn,Pnma, Pnma ) and Bi3Se4Br possess a monoclinic crystal structure (space group C2/m). According to the band structure analysis BiSeI, BiSeBr, Bi3Se4Br and BiSI are found to possess optical band gaps in between 1-1.9 eV. The crystal structure of BiSeBr, and BiSeI has chains of atoms running along the c-axis and have similar electronic properties, including similar optical band gaps of 1.54 eV and 1.56 eV, respectively. The crystal structure of Bi3Se4Br shows atomic chains, along the b axis and the calculated band structure is indicates an indirect bandgap (~1.04 eV) with the CBM at k point along the -M direction and VBM along the N-Z direction. BiSI shows well-separated groups of bands and reveal that BiSI crystal has an indirect forbidden gap (1.87eV). The minimum of the conduction band is located at ƛ point and the maximum of the valence band appears nearly midway between the Z and ƛ points. Generally, band gap greater than 1.5 eV can be used for radiation detection applications and further analysis could be carried out to find potential as room-temperature radiation detection materials. According to this study, the band gaps of BiSeI, BiSeBr,Bi3Se4Br and BiSI are in the range of band gap required for photovoltaics. Furthermore, other electronic properties, including the effective mass, optical absorption. should be investigated to check the applicability in various optoelectronic devices.
- item: Conference-AbstractEffect of vein graphite powder on dynamical properties of solid tire vulcanizate(Department of Materials Science and Engineering, University of Moratuwa., 2023-12-14) Somaweera, D; Abeygunawardane, GA; Weragoda, SC; Ranatunga, S; Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, KIn the construction of solid resilient tires, three layers named tread, cushion, and base are integrated. The cushion, situated in the middle, not only contributes to a comfortable ride but also plays a crucial role in mitigating heat buildup under heavy loads. This study aims to optimize the properties of the cushion compound in solid tires by incorporating Sri Lankan vein graphite powder as a filler. This study investigates the dynamic properties of graphite-filled solid tire compounds under frequency sweep and strain sweep. Frequency sweep was given at 100°C and 10% strain. Complex viscosity of both unfilled and graphite-filled compounds exhibits shear-thinning behavior at lower frequencies, transitioning to Newtonian behavior at higher frequencies. Graphite loading influences these properties, with the 2% graphite-filled compound demonstrating the highest shear-thinning behavior and viscosity. The complex shear modulus (G*), inversely proportional to viscosity, decreases with graphite loading, with the 2% graphite-filled compound exhibiting the highest modulus. Storage (G') and loss (G'') moduli, representing elastic and viscous behavior, are influenced by graphite loading, mirroring the complex shear modulus trends. The damping factor, indicating energy dissipation, decreases with frequency and increases with graphite loading. Strain sweep analysis reveals linear behavior at low strains, transitioning to non-linear behavior beyond a critical strain, influenced by graphite content. The 10% graphite-filled compound shows distinctive behavior, exhibiting the highest damping factor at both low strains and in the entire frequency range. Overall, the study provides comprehensive insights into the viscoelastic characteristics of graphite-filled solid tire compounds, crucial for optimizing tire performance.
- item: Conference-AbstractUnveiling the barrier: a simulation study on face mask filtration(Department of Materials Science and Engineering, University of Moratuwa., 2023-12-14) Panawala, SS; Mudalige, SP; Amarasinghe, DAS; Attygalle, D; Samarasekara, AMPB; Weragoda, SC; Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, KIn recent years, there has been significant discussion surrounding fibrous filters, particularly in relation to respiratory masks. Manufacturing fibrous filters involves paying close attention to the sticking coefficient of fibers and ensuring its stability under different climatic conditions. This paper presents an optimal range of filter characteristics that maximize filtration efficiency, considering factors such as sticking coefficient, inter-fiber distance, and fiber diameter. The findings were obtained through computational modeling of aerosol diffusion within fibrous filters. The identified optimal region demonstrates that achieving nearly maximum filtration efficiency does not require indiscriminately increasing the sticking coefficient; surpassing a marginal value of 0.5 is sufficient. This outcome can prevent unnecessary overdesign and contribute to reducing production costs.
- item: Conference-AbstractAdvancements in research into piezoelectric energy harvesting insights from the research group of materials science and engineering department(Department of Materials Science and Engineering, University of Moratuwa., 2023-10-14) Samaraweera, RLU; Adikary, SU; Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, KThis unveils the remarkable progress in piezoelectric energy harvesting conducted by piezoelectric energy harvesting research group of the Department of Material Science and Engineering at the University of Moratuwa. Energy harvesting research seamlessly transforms from macro to nano levels based on international trends while emphasizing the critical aspect of system efficiency. At the macro level, a sophisticated vibration energy harvesting device designed for vehicles takes center stage. Lead zirconate titanate (PZT) was strategically chosen as the piezoelectric material, and analysis of vibration sources was undertaken to pinpoint resonant frequencies. This investigation led to the development of a robust prototype utilizing a cantilever-type configuration, wherein the Euler–Bernoulli beam theory and finite element analysis played pivotal roles in optimizing design parameters. The theoretical modeling predicted a maximum voltage, setting the stage for the practical implementation of the prototype on a motorbike. The measured output not only validated the theoretical predictions but also highlighted the real-world applicability of the macro-scale piezoelectric energy harvesting device, particularly in the context of vehicular vibrations. Based on the international trends, it seamlessly transformed into the nano-scale realm, exploring vertically integrated zinc oxide piezoelectric nanowire arrays. Leveraging COMSOL Multiphysics software, the study modeled and simulated various nanogenerator structures. Here, the focus shifts from sheer nanowire quantity to the nuanced consideration of nanowire density, revealing that the total electric energy harvested is intricately linked to density rather than the absolute number of nanowires. This shift in scale, from macro to nano, is not just a change in dimension but a deliberate evolution in understanding and optimizing piezoelectric systems. The presentation underscores a holistic journey, from macro-level vibrational energy harvesting in practical vehicular applications to the intricacies of nano-level structures, all the while emphasizing the paramount importance of system efficiency in advancing the frontiers of piezoelectric research.
- item: Conference-AbstractSustainable synthesis of cellulose acetate from cotton waste(Department of Materials Science and Engineering, University of Moratuwa., 2023-12-14) Kantha, WDY; Madusanka, SDC; Samarasekara, AMPB; Amarasinghe, DAS; Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, KThis research presents an innovative approach to the synthesis of cellulose acetate from cotton waste, contributing to sustainable materials development. Cotton waste, a byproduct of textile processing, is an abundant and underutilized resource. The study focuses on extracting cellulose, a natural polymer found in cotton fibers, as a precursor for cellulose acetate production. In this study, cellulose was extracted from cotton wool using a simple, cost-effective method. The extraction process involved the alkaline peroxide pretreatment of cotton wool with a mixture of sodium hydroxide and hydrogen peroxide at 95 °C for 1 hour. The extracted cellulose was then characterized using Fourier transform infrared spectroscopy (FTIR) to confirm the removal of lignin and hemicellulose. The FTIR analysis indicated the presence of cellulose and removal of functional groups of lignin and hemicellulose. The extracted cellulose was then chemically modified using acetic anhydride and acetic acid under different reaction conditions by going through the processes of activation, acetylation, and hydrolysis respectively. The resultant cellulose acetate sample was centrifuged to sediment at 1500 rpm for 15 minutes. This cellulose acetate finds applications in textiles, packaging, and biomedical fields due to its exceptional properties, including biodegradability, film-forming capability, and compatibility with various industries. The results of this research contribute to the growing field of environmentally friendly material synthesis, providing a practical and sustainable method for synthesizing cellulose acetate.
- item: Conference-AbstractNumerical simulation of bisi and bisei absorber materials based solar cells(Department of Materials Science and Engineering, University of Moratuwa., 2023-12-14) Wickramaarachchi, A; Sewwandi, GA; Buddhima, P; Indeewari, A; Gurusinghe, Y; Konalingam, KRecent advancements in perovskite solar cells have improved their stability and addressed toxicity concerns, making them more commercially viable. These cells not only have a less energy-intensive manufacturing process but can also be lead-free, aligning with environmental sustainability goals. The research is centered on numerically simulating lead-free bismuth chalcohalides Solar Cells based on thin films of Bismuth Sulfur Iodide (BiSI) and Bismuth Selenium Iodide (BiSeI) through the Solar Cell Capacitance Simulator (SCAPS 1D). The cell architecture comprising with the titanium dioxide (TiO2) for the electron transport layer (ETM) and the Spiro-OMeTAD for the hole transport layer (HTM). Furthermore, Bismuth Sulfur Iodide (BiSI) and Bismuth Selenium Iodide (BiSeI) were used as the absorbing layers, sandwiched between two electrode materials. Specifically, Fluorine-doped tin dioxide (FTO) served as the front electrode contact, and Gold (Au) was utilized as the back electrode contact. This study investigated the performances of the cell by varying thickness of the absorbing layer and the operating temperature. The maximum power conversion efficiency (PCE) of 16.19% (Voc of 1.01 V, rent Jsc of 28 mA/cm2, and FF of 56.37%) is obtained at 1500 nm BiSI layer thickness for an optimized device. The maximum PCE of 22.59 % (Voc of 1.18 V, Jsc of 32 mA/cm2, and FF of 59.15 %) is obtained at 1500 nm BiSeI layer thickness for an optimized device, and the optimized device temperature range was determined to be between 290K and 310K while determining 1500 nm as the optimum thickness of the absorbing layer. The results showed that BiSeI demonstrated superior photovoltaic characteristics at an optimum thickness of 1.5μm compared to BiSI. However, both materials exhibited a significant decrease in performance as the temperature of the photovoltaic cell increased. However, 290K to 310K can be considered as the optimized device temperature range as only slight loss of performance of the material can be observed in the same region of temperature.