Master of Philosophy (M.Phil.)

Permanent URI for this collectionhttp://192.248.9.226/handle/123/18719

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item: Thesis-Full-text
Application of nanoclay on polyester fabrics as a bio-inspired approach to improve moisture management
(2018) Abeywardena, SBY; Walpalage, S; Perera, WPSK; Somararatne, MCW
Bio-inspired and biomimetic surface modifications are identified as one of the fascinating areas of research. In this study, nature’s way of cooling elephants’ body temperature using mud bathing was mimicked to create moisture management in polyester fabric. For that, bentonite nanoclay (BNC) was covalently grafted on polyester fabric using (3-aminopropyl) triethoxysilane (APTES) as a coupling agent. The novel modification method was proved qualitatively and quantitatively using characterization techniques such as X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Xray fluorescence (XRF) and Thermo gravimetric analysis (TGA). Moisture management tests, and physical and mechanical properties of modified polyester fabric were used to analyse the accomplishment of the modification. Hydroxyl groups on edges of BNC played a vital role in grafting with APTES. Primary amine group in APTES reacted with ester groups in polyester fibres, while silanols reacted with BNC. XRD analysis confirmed grafting of APTES on the surface of BNC without intercalation. XPS and FTIR spectroscopies confirmed the new secondary amide bond formation, while surface morphology was observed from SEM images. The significant enhancement in wettability, absorptive capacity, drying rate and wicking length proved moisture management property of polyester fabric. This fabric coating strongly withstood more than 10 cycles of laundry and against 5000 abrasion cycles. Physical and mechanical properties of modified fabrics remained unchanged, while tensile strength and elongation showed a slight improvement due to fibre preserving aminolysis reaction between APTES and ester groups in polyester fabrics. It is expected that this bio-inspired BNC modified polyester fabric may break the barrier of using polyester in various hydrophilic textile applications.
item: Thesis-Full-text
Characterization of calcium carbonate filled natural rubber - low density polyethylene blends prepared with a titanate coupling agent
(2019) Sampath WDM; Egodage SM; Edirisinghe DG
The aim of this study was to develop reactive blends from natural rubber (NR) and low density polyethylene (LDPE) with acceptable physico-mechanical properties. NR and LDPE blends at different blend ratios were produced in a Brabender Plasticorder by melt mixing at a temperature of 150 oC, and rotor speed of 60 rpm. 20 parts per hundred parts of polymer (pphp) calcium carbonate was added as an inorganic filler. Physico-mechanical and chemical properties of the blends and composites were determined according to international standards. Thermal properties were determined using a differential scanning calorimeter. Morphology and structural characteristics were examined by a scanning electron microscope and fourier transform infrared analyzer, respectively. 50/50 NR/LDPE blends were prepared using three vulcanizing systems: sulphur, peroxide and mixture of sulphur and peroxide. NR/LDPE blend prepared with the mixed vulcanizing system showed the highest physicomechanical, chemical, and ageing properties with a fine morphology. A series of simple blends was formulated by varying the LDPE loading from 10 to 90 pphp at 20 pphp intervals. The tensile strength, tear strength, and hardness increased with the increase of LDPE loading, while elongation at break decreased. The continuous phase of blends changed from NR to LDPE above 30 pphp LDPE loading. The optimum tensile and ageing properties were obtained for the composite prepared with 20 pphp calcium carbonate with or without titanate coupling agent (titanate CA) at 30 pphp LDPE loading. Further, 70/30 NR/LDPE composite prepared with 0.7 pphp titanate CA presented the highest physicomechanical, chemical and ageing properties. Furthermore, the performance of the 70/30 NR/LDPE blends produced with 0.3 pphp peroxide was greater than that of the composites prepared without the peroxide and with a high amount of peroxide. Nevertheless, tensile properties, stress and strain of the 70/30 NR/LDPE composite improved with partial replacement of LDPE with recycled LDPE (rLDPE). The composite with 20 pphp rLDPE indicated the best improvement in all physico-mechanical properties.
item: Thesis-Full-text
Development of a national risk acceptance criteria for managing major industrial hazards
(2018) De Silva, KGVK; De Alwis, AAP; Gunasekera, MY
This work attempts to address the issue of managing risk to the safety of the public posed by Major Accident Hazards (MAH) from the Chemical Process Industry (CPI) in Sri Lanka. The research essentially focuses on the establishment of a suitable risk acceptance criteria as well as an appropriate framework that can be used in determining the level of safety offered by a particular MAH installation in Sri Lanka. The “level of safety” of an installation is then compared against the risk acceptance criteria to determine its acceptability in the Sri Lankan context. The history of process safety management as is understood at present was investigated and the different risk regulation regimes currently in practice globally were identified. The role of risk assessment in each risk regulatory regime was investigated and the need for risk informed decision making was firmly established. The thesis then focuses on the prevalent categories of approaches in risk assessment. The different risk assessment approaches are investigated further. Out of those approaches, the consequence assessment and probabilistic risk assessment approaches or methods were chosen for the development of the risk assessment framework. The different risk metrics used to express the risk for each approach and the respective risk acceptance criteria were identified. Then appropriate risk acceptance criteria were developed for the two approaches. The establishment of a safety distance corresponding to 1% fatality of the public was adopted for the consequence based assessment method whereas a FN criteria line with an anchor point of (10, 10-4) and slope -1 was chosen for the probabilistic risk assessment method. The applicability of the different risk acceptance criteria in the Sri Lankan context is carried out for the case of propane storage tank. Data gaps and constraints are identified. Both methods adopt a conservative decision making approach. A significant constraint is the lack of a nationally verified and validated set of failure rate data for process equipment and ignition probability data; these are essential for establishing conditional probabilities when calculating accident frequencies. The usage of generic data for failure rates is not recommended due to the wide variability in different data sources. Further, allowing room for choosing an arbitrary set of failure rate data could create an opportunity for biasing the risk acceptance decision. In this work, a framework is presented for applying the risk acceptance criteria developed. An FN curve based on upper bound data for the probabilistic risk assessment method and modified consequence assessment method are developed. The probabilistic risk assessment method is modified to accommodate the variability in generic failure rate data. The decision of acceptability is made by defining an FN curve using upper bound values of the FN curve and comparing it with the criterion line. A safety distance proportionate with the overall level of risk based on a relative risk reduction factor (RRRF) is introduced.
item: Thesis-Full-text
Methodology for comparison of chemical process routes based on environment, health and safety aspects at early stages of chemical process plant design
(2018) Anuradha HBB; Gunasekara MY; Gunapala O
The chemical process route selection is one of the important decisions that needs to be taken during initial stages of plant design and development. Although conventionally the economic factor has been considered in this selection process, presently the environmental, health and safety (EHS) issues have also become main concerns as hazards related to EHS can be largely reduced by avoiding them during initial stages of plant development. Therefore, in order to select a route, the assessment of alternate chemical process routes based on EHS aspects and their comparison need to be carried out. For this assessment, comparison and selection methodologies are needed. Most of the methodologies available for chemical process routes assessment and selection, consider mainly environmental or health or safety hazards individually or in combination of two of them. Although few methodologies are available that consider all three EHS aspects, those that consider EHS hazards posed by both types of releases namely daily plant operational and accidental are lacking. In this work fuzzy based inherent environmental, health and safety hazard index called EHS-Fuzzy Index is developed to compare chemical process routes based on integrated EHS hazards due to daily operational activities of the plant as well as accidental releases. The EHS-Fuzzy Index includes information of thirteen EHS related parameters which is available during routes selection stage. The lower the EHS-Fuzzy Index the more environmental friendly, occupational healthy and safer the chemical route. Further, this methodology can be used to compare and rank alternative chemical routes based on environmental hazard or health hazard and safety impact separately as well. The EHS-Fuzzy Index was applied in a case of six routes to manufacture methyl methacrylate (MMA). The Tertiary Butyl Alcohol (TBA) chemical route to manufacture MMA showed the least EHS-Fuzzy Index value. By applying the MMA case study in the radial polygon diagram method, the results obtained using the EHS-Fuzzy Index methodology were verified.

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Browsing Master of Philosophy (M.Phil.) by Subject "CHEMICAL AND PROCESS ENGINEERING-Dissertations"