University of Sri Jayewardenepura: Journals & Proceedings
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Surface Modification of Montmorillonite Clay Towards the Fabrication of Nanocomposites for Engineering Applications
Get PDFMontmorillonite (MMT) is a layered clay mineral composed of silica and alumina sheets with a layer thickness of about 1 nm qualifies it as a two-dimensional nanomaterial. MMT is found in natural clay ores in the Murunkan, Kirinda, and Okanda areas in Sri Lanka. Nanocomposites with enhanced physical and mechanical properties can be prepared by dispersing MMT in a polymer matrix. However, the hydrophilic nature of MMT hinders the incorporation of MMT into hydrophobic polymer matrices. Hence, a suitable surface modification is required to make MMT compatible with polymers. The present study was based on the preparation and analysis of organically modified calcium Montmorillonite (Ca-MMT)-polypropylene nanocomposites as a green technology initiative. Homo-ionic Ca-MMT was prepared by treating commercial MMT-K10 with a CaCl2 solution. The predominant exchangeable divalent cations present in MMT-K10 and Ca-MMT were determined using AAS. The cation exchange capacity of Ca-MMT was about two times greater than that of MMT-K10. Furthermore, XRD analysis showed a slight increase in d- spacing of Ca-MMT compared to MMT-K10. A novel ligand, triethylene glycol dodecyl methyl ether was synthesized by treating triethylene glycol monomethyl ether (TGME) with 50% w/w aqueous solution of sodium hydroxide followed by 1-bromododecane with the molar ratio of TGME:NaOH:1-bromododecane in 1:2:2. The crude product was purified by column chromatography and characterized by FTIR and GCMS analysis. Hydrophilic Ca-MMT was surface modified with the organic ligand presumably via the coordination of triethylene glycol moiety with Ca2+ cations at the outer edge of the MMT particles. The long aliphatic chains in the periphery of the modified MMT particle make it more organophilic. Modified Ca-MMT was characterized by XRD, TGA, and FTIR analysis. The XRD revealed a slight increase in the d-spacing related to the 001 plane of modified Ca-MMT compared to unmodified clay. The effect of modified Ca-MMT loadings (0.5%, 1%, and 1.5%) on the mechanical properties of the nanocomposite was studied. The results implied an enhancement of the mechanical properties in terms of impact resistance, hardness, and flexural properties in the nanocomposite compared to the virgin polymer. The fabricated nanocomposite is a promising engineering material that may have applications in automotive, construction, and packaging products.
Keywords: Montmorillonite, Polypropylene, Nanocomposite, TGME, Compatibility
 
Geochemical Signature and Micromorphology of Ferruginous Gravel and Laterite Deposits in Northern Sri Lanka
No full textFerruginous gravel is an iron-cemented clastic sedimentary deposit that covers most of the northern province with interconnecting laterite and red earth deposits. The study is conducting a novel investigation of the detailed geochemistry and micromorphology of the ferruginous gravel and laterite deposits in northern Sri Lanka. Two profiles were selected for detailed investigation in the Mullaitivu district and collected samples from two profiles were analysed for micromorphology, phase identification, and the geochemical signature of the ferruginous gravel and laterite deposits using scanning electron microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma mass spectrometry (ICP-MS), respectively. SEM images of thin sections revealed the nature of microfractures, cavities, and authigenic minerals, including goethite and kaolinite, in the ferruginous gravel and laterite deposits. XRD analysis confirmed the dominance of quartz and goethite, with minor kaolinite peaks. Fe-Al-V-Cr-Mn-Ge-Ba is the major element, and traces of rare earth elements were identified using ICP-MS data. The similar mineral and chemical compositions of ferruginous gravel and laterite deposits suggest a common formation pathway under intense weathering conditions, leading to silica-rich, iron-cemented, clastic sedimentary deposits highlighting their unique characteristics.
Keywords: Ferruginous gravel, Laterite, Micromorphology, Geochemistry, Clastic sediment
Comparative Nutritional Analysis of Six Selective Small Pelagic Fish Species in Sri Lanka
No full textFish constitutes a crucial dietary staple in Sri Lanka, largely due to the economic significance of fishing in local communities. However, a disparity exists between the recognition of small pelagic fish and larger common pelagic species. They are often identified as less economically important in fish marketing, and very much popular among the economically disadvantaged local community, compared to large pelagic fish. Small pelagic fish are undervalued because of their higher bone-to- flesh ratio. This study seeks to highlight the nutritional importance of these underappreciated six small pelagic fish species, particularly among low to middle-income communities as a cheap protein source. The species were chosen for their cost-effectiveness and abundance during off- seasons and collected from the Negombo and Chillaw fish market. The samples were confirmed with The Marine Fish Source of Sri Lanka; identified as Salaya (Goldstripe Sardinella/ Sardinella gibbosa), Sura-paraw (Yellowstripe scad/ Selaroides leptolepis), Mas-Panna (Toothpony/ Gazza minuta), Katilla (Bald glassy/ Ambassis gymnocephalus), Katumassa ( Kelee shad/ Hilsa kelee), and Oleya (Saddleback silverbiddy/ Gerres lucidus). The Total Length (TL), Fork Length (FL), and Standard Length (SL), were measured in cm (n=30), and samples were further subjected to proximate analysis such as moisture, crude-protein, crude-fat, and ash contents at dry-basis (n=3) by following AOAC standards and results were statistically analyzed using Minitab-19. Among the six selected fish species, Katumassa was recorded the highest TL (14.75±1.06), FL (12.57±0.84) and SL (11.62±0.87), while Katilla was recorded the least values as TL (7.14±0.37), FL (5.96±0.37) and SL (5.38±0.25). The significant differences were observed in moisture, crude-protein, crude-fat, and ash percentages for the fish species of Katilla and Oleya; Katumassa and Salaya; Oleya and Katilla; and Mas-panna and Oleya (p<0.05, 95% confidence level) respectively. Minimal attention in nutritional studies and the impact of cooking and consumption on the nutritional profiles of the aforementioned species has not been extensively studied from both local and global studies, hold potential for the development of functional processed food sources. It is imperative to encourage the community to comprehend the significance of small pelagic fish in fostering sustainable dietary practices and emphasize the importance of further research, particularly technology-driven investigations, aimed at harnessing the untapped potential of these underutilized resources in the food industry.
Keywords: Small pelagic fish, Marine fish source, Proximate composition, Underutilized fish species
 
Assessment of Heavy Metal Accumulation in Freshwater Fishes in Irrigation Tanks, Anuradhapura
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Sri Lanka is well known for its dense freshwater irrigation tanks, especially in dry zones, which play an important role in sustaining both the environment and human livelihoods by providing essential resources such as drinking water, irrigation for agriculture, and nutrition through fish proteins. However, heavy metal contamination poses a significant threat to the sustainability of these valuable freshwater irrigation tanks due to their persistence and non-biodegradability. These heavy metals tend to accumulate in living organisms and biomagnified and have harmful effects on high tropic level organisms like humans who rely on aquatic fish species via food chains. This study was carried out to assess the heavy metal accumulation in muscle and liver parts of freshwater fishes, Tilapia (Oreochromis sp.), and striped snakehead; Lula (Channa striata) in Kammalakkulama, Hammillewa, Kirindegama, and Madawalagama tanks in Anuradhapura district, Sri Lanka. The Inductively coupled plasma mass spectrometry (ICP-MS) was used to analyse the randomly collected fish samples for total Cadmium (Cd), Arsenic (As), Lead (Pb), and Mercury (Hg) in the tanks. The results indicated a significant difference (p<0.05) in the detected concentrations of heavy metal levels in tested samples among the four tanks. The highest concentrations of Cd (2.098 mg/kg) and As (0.366 mg/kg) were recorded in the liver of Tilapia in the Kammalakkulama tank. The highest Pb (5.509 mg/kg) and Hg (2.015 mg/kg) concentration was recorded in the Tilapia muscle in the Hammillewa tank and the Lula muscle in the Madawalagama tank respectively exceeding the WHO/FAO standards. The accumulation levels of these heavy metals were higher in the fish liver compared to their muscle in most of the samples. Arsenic (As) showed a significant positive linear relationship (R2=0.531) between their dry body weight and accumulated concentration in the Tilapia muscle. The canonical discriminant analysis showed a significant differentiation among the four tanks concerning heavy metal levels in fish tissues.
Keywords: Channa striata, Heavy metals, Irrigation tanks, ICP-MS, Oreochromis sp
A Critical Appraisal of the International and National Legal Framework on Climate Change
Get PDFThe decade starting from 2010-2020 was recorded the warmest decade in the history. The new principles such as Climate litigation, climate justice, climate legislation have been catapulted to the forefront of the environmental litigation and environmental laws. As per the United Nations Framework Convention on Climate Change (UNFCC) the human activities is the substantial cause for increasing of Greenhouse gases in the atmosphere which would results in additional warming of the earth‘s surface and the atmosphere and also may adversely affect the natural eco system and human kind. Article 2 of the UNFCCC defines climate change as, a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. Changes in the physical environment or biota resulting from climate change which have significant deleterious effects on the composition, resilience or productivity of natural and managed ecosystems or on the operation of socio-economic systems or on human health and welfare are the effects of climate change. As a matter of fact climate change is the direct result of global warming and the emission of greenhouse gases to the atmosphere has escalated the earth‘s temperature level. The Resolution adopted by the General Assembly which includes 2030 Agenda for Sustainable Development urges States to take urgent action to combat climate. UNFCC, Kyoto Protocol and Paris Agreement constitute the international legal regime that deals with climate change. These were the results of entering into international consensus in the aim of reducing the greenhouse emission and thereby to effectively handle the climate change impacts. The objective of the paper is centered on the appraisal of the international and national legal framework that have been enacted to curb the climate change. To this end the research paper employs a qualitative methodology. Conventions, Resolutions adopted by the United Nations, legislations such as National Environment Act, Fauna and Flora Act, Coastal Conservation Act etc , policies and regulations, case laws from foreign jurisdiction are utilized as primary sources and the scholarly articles, journals, peer reviewed articles are utilized as secondary sources. The findings of the paper emphasizes that the synergy between the international and national legislations should be strengthen if the legislature is to find prolific solutions to this complex issue. Finally the paper concludes that it must be taken into consideration that if all States are to combat this unprecedented crisis, no instrument can be ignored.
Keywords: Climate change, Climate litigation, Environment, Global warming, Sustainable developmen
Enhancing Sustainability and Performance of Pineapple Leaf Fibres in Textile Applications: A Comprehensive Review
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The utilization of pineapple leaves (Ananas comosus) has gained significant momentum as a source of value-added products, owing to the myriad benefits offered by Pineapple Leaf Fibres (PALF). PALF presents a range of advantages, including its contribution to a greener environment and sustainability. PALF production plays a pivotal role in reducing environmental pollution and minimizing waste. Moreover, PALF stands out due to its availability, remarkable thermal and acoustic insulation properties, cost-effectiveness, and exceptional tensile strength. Further, the extraction of PALF can be accomplished manually or mechanically, and various methods have been explored to enhance its compatibility with textile applications. In this context, extensive research has been carried out to modify PALF for its application in the textile industry. Researchers have primarily focused on surface modifications. These modifications encompass chemical treatments, physicochemical treatments, physical treatments, and thermal treatments. All of these contribute to improved interfacial adhesion and enhanced physical, mechanical, and thermal properties of PALF. Additionally, investigations into bleaching and dyeing of PALF have led to achieving superior whiteness and the ability to impart various colours to the fibres. PALF fibres exhibit remarkable qualities, including excellent sweat absorption, breathability, durability, and notable air and water permeability. These attributes make PALF a sought-after material for creating blended fabrics in conjunction with other polymers, such as polyester and wool, enhancing the performance of resulting textiles. The versatility of PALF enable its integration into an extensive range of textile products, underscoring its significance in the industry. This review also explores innovative approaches, such as blending PALF with jute, resulting in the creation of home textiles and carpets, while simultaneously improving the quality of blended yarns. Furthermore, within the textile industry, PALF fibres find diverse applications in the production of an array of products. This involves the crafting of wedding dresses, casual attire, and formal garments. It also includes the manufacturing of table linens, mats, bags, shoes, belts, cords, transmission cloths, airbag tying cords, and carpets. This comprehensive review delves into the wealth of research conducted on PALF modifications, shedding light on the potential of PALF as a sustainable and high- performance material in the textile industry, contributing to further eco-friendly and innovative future.
Keywords: Pineapple Leaf Fibres (PALF), Textile Industry, Sustainability, Greener environmen
A Review on the Utilization of Herbarium Data in Phenological Research Addressing Climate Change Implications
Get PDFIn recent years, the profound impact of climate change on biodiversity has become increasingly evident, with significant consequences for critical life events in the natural world. It underscores the significant influence of climate variations on seasonal life events within the biotic environment of flora, such as blooming response, leaf growth, leaf senescence and fruit ripening. These phenological shifts, particularly in temperate and tropical ecosystems, serve as vital indicators of climatic changes. This review study delves into the intricate relationship of herbarium data for bridging the gap in plant phenological observation for the investigations on climatic change. This comprehensive literature review of 30 key research papers published in the past two decades, which focus on the utility of herbarium specimens as tools to document phenological changes, was critically analysed in this research study. Long-term observation of phenological data by various phenological observation networks has paved the way for advanced environmental analysis in climatic change studies. However, despite the importance of phenological data from field observation, its collection and long-term observation records, present challenges, emphasizing the need for spatiotemporal depth of phenological data. A noticeable gap in field data collection has hindered various studies reliant on plant phenological data. In response to these challenges, herbaria serve as invaluable repositories of plant specimens, boasting rich historical records spanning over a century, providing a deep spatiotemporal and taxonomic insight. Research findings indicate the fidelity of herbarium records to fill the gap in field observations, with no significant differences between the field observations and herbarium data, highlighting the reliability of herbarium data in capturing phenological information. Overcoming the challenges associated with extensive herbarium datasets, digitalization and the implementation of crowdsourcing platforms have emerged as effective strategies, granting researchers easy online access to these data. Moreover, it is evident that in Sri Lanka, there exists a research gap in utilizing herbarium data for phenological studies in climate change observation and the implementation of online accessibility for herbarium data, highlighting the need to address this gap in future research endeavours.
Keywords: Climate change, Herbarium data, Biodiversity, Phenological dat
A New Three-Pillar Score System to Reduce the Sustainable Subset Heterogeneity within the GREENSL Rating System in Sri Lanka
Get PDFSustainable development is achievable only by integrating and acknowledging three main sustainability pillars (Environment, Social, and Economic) during the decision-making process. Sustainable/Green construction has become a major part of the sustainable development process in Sri Lanka today. Sustainable/Green buildings are evaluated using both international (LEED, BREEAM, CASBEE, Green globes, etc.) and local (GREENSL, Blue-Green Sri Lanka) green building rating systems. Most of these international green building rating systems have unequal credit point distribution among three sustainability subsets which causes heterogeneity among subsets. Thus, this research was designed to evaluate two local green building rating systems (GREENSL Version 2.0, and Blue-Green Sri Lanka for government constructions Version 1.0) to identify this heterogeneity in the local context. The credit point distribution among three sustainability subsets within the two selected rating systems was evaluated by analyzing the categories and criteria of these two rating systems. Here, when criteria represented one or more pillars of sustainability, the credit points belonging to such criteria were equally divided into those two subsets. The results revealed that three subsets were not equally considered in the GREENSL (Environment (52.1%), Social (21.6%), Economic (26.3%)) and Blue-green Sri Lanka for government constructions (Environment (48.4%), Social (17.2%), Economic (34.4%)) rating systems. Thus, there is a sustainable subset heterogeneity that is dominated by environmental sustainability. As achieving the exact 33.3% point distribution among three sustainability pillars is difficult, new point distribution percentages were proposed as 40% for the environment and 30% each for both social and economic sustainability pillars. Finally, a new three-pillar score system was proposed that can be used together with the GREENSL overall score for the buildings to reduce this subset heterogeneity by adopting the proposed point distribution percentages above. This study suggested that the building needs to fulfill both the total category score and the proposed three- pillar score to qualify for the respective GREENSL award (Platinum, Gold, Silver, and Green certified) to reduce the sustainable subset heterogeneity within this rating system.
Keywords: GREENSL for the built environment, Sustainability subsets, Sustainable subset heterogeneity, Three-pillar score syste
Conversion of Marginalized Tea Lands into Timber Plantations and its Impact on Soil Organic Carbon Content: A Case Study in Central Highlands of Sri Lanka
Get PDFTea (Camellia sinensis) plantations can be in production for about 100 years under well-managed conditions. However, soil degradation makes the tea lands marginalized and uneconomical. Land use conversion is an option for marginalized tea lands that could gain numerous environmental and economic benefits. This study estimated and compared the soil organic carbon stocks (SOC) in the surface soil layer (0–30 cm) of marginalized tea lands against those converted to timber plantations in the Badulla and Nuwaraeliya districts. Disturbed and undisturbed soil samples were collected from the top layer (0-30 cm) of the selected sites of marginalized tea lands and those converted to timber plantations for analysis. Organic matter percentage in the site-level dry soil samples was analysed using the loss on ignition method. The final carbon stocks (t C ha-1) for samples from both land use types were then estimated using the SOC percentages and bulk density estimates. The carbon stocks for the soil samples collected at marginalized tea lands and the marginalized tea lands converted to timber plantations were then statistically analysed (descriptive statistics, normality tests and two-sample t-tests) using Minitab 21.2 software. The pH of marginal tea lands (5.34±0.14) and the marginal tea lands converted to timber plantations (5.20±0.13) was slightly acidic in nature. The bulk density estimates of marginalized tea lands and marginalized tea lands converted to timber plantations were very close and estimated as 1.15±0.02. The statistical analysis showed that overall mean SOC was significantly higher under the marginalized tea lands converted to timber plantations (155.3±10.0 t C ha-1) compared to the marginalized tea lands (126.7±5.8 t C ha-1). Land use conversion has increased the SOC stocks gradually after forest establishment. The increased carbon stocks could be attributed to consistent addition of litter layer on the soil, less soil disturbance, and retarded soil erosion contributing to the buildup of soil organic matter and SOC. On the other hand, low carbon stocks in the marginalized tea land could be attributed to unsustainable agronomical practices. Our findings suggest that converting marginalized tea lands in central highlands into timber plantations could enhance the sequestration of atmospheric CO2, significantly contributing to climate change mitigation.
Keywords: Soil organic carbon, Land use change, Climate change, Tea plantation
A Sustainable Form of Land Use under Borassus flabellifer: A Case Study in Jaffna District of Sri Lanka
Get PDFPerennial plantations play a significant role in mitigating climate change and improve the plant diversity. This study was carried out to estimate the carbon sequestration potential of Plamyrah (Borassus flabellifer) land use in twelve different soil series in Jaffna district and to estimate the plant diversity of the same. Samples were collected from sampling quadrates of 10 mx10 m. A total of 75 quadrates were sampled. Numbers of quadrates in each soil series were selected based on the extent of Palmyrah plants and soil series. From each quadrate following data was collected: number of Palmyrah trees and other trees and their height and diameter at breast height. Soil samples were also collected within each quadrate at three depths, up to a depth of 30 cm. For the estimation of biomass carbon stock Palmyrah wood density was determined using 15 wood samples. Biomass carbon was estimated using the standard equations. Soil organic carbon percentage was determined by loss on ignition method. The total carbon stock was determined by the summation of carbon in palm biomass and soil carbon. Plant diversity was estimated in terms of number of species, Shannan Weiver index (SWI) and evenness. Soil organic carbon percentage of Palmyrah land use in different soil series ranged between 1.1-4.5%. Soil organic carbon stock in different soil series ranged 51-190 Mg/ha. There was no significance difference among soil organic carbon percentage of Palmyra land use in different soil series. Top most layer (0-10 cm) had significantly higher amount of soil organic carbon than sub surface layers (10-20 cm, 20-30 cm). Palm density of Plamyrah land uses in different soil series ranged 5-13/100 m2. Biomass carbon stock ranged between 2.83-6.80 Mg/100 m2. Biomass carbon stock in different soil series was significantly differed. Total carbon stock ranged 4.06-7.97 Mg/100 m2. A total of 22 plant species belonging to 13 families were identified in the Palmyrah land uses in the study area. Arecaceae family was vastly distributed in the palmyrah land use while Poaceae and Malvaceae were the poorly distributed ones. The mean value of Shannan Weiver Index (SWI) was 1.2 while evenness was 0.74. This study therefore concludes that the Plamyrah land use in the study area has great potential to sequester carbon in long term, while maintaining a reasonable tree species diversity.
Keywords: Soil carbon, Biomass carbon, Plant diversity, Carbon stoc