ISERME - 2024

Permanent URI for this collectionhttp://192.248.9.226/handle/123/22912

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Now showing 1 - 20 of 49
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    item: Conference-Abstract
    International Symposium on Earth Resources Management & Environment 2024 (Pre-Text)
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
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    item: Conference-Full-text
    Numerical analysis of fluid permeability in compacted sandstones
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Miura, O; Oishi, R; Harada, S; Yagi, T; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Fluid permeability in compacted sandstones were investigated numerically. The structural analysis of spherical particle bed which imitates compacted sand layer was conducted and pore region in the particle bed was extracted. The pore characteristics, such as effective porosity, tortuosity and specific surface area, were quantified by various numerical methods. From these pore characteristics, fluid permeability was calculated using the Kozeny-Carman equation. The obtained permeability agreed quantitatively with those measured from actual sandstones.
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    item: Conference-Full-text
    Effect of fracture stiffness in a fault damage zone on seismic source parameters of induced fault-slip
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Gang, M; Sainoki, A; Kodama, J; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    It is well recognized that inherent stress concentration within a fault damage zone may lead to induced fault-slip, resulting in severe damage to underground facilities. Previous research suggests that the intensity of fault-slip is influenced not only by the mechanical properties of the fault core but also by the stiffness of the surrounding rock mass, implying that fracture stiffness could be an important factor that needs to be studied. Therefore, in this study, the effect of the fracture stiffness on seismic source parameters of induced fault-slip is investigated using a mine-wide scale heterogeneous continuum model. The model is constructed based on a discrete fracture network within a fault damage zone, utilizing the crack tensor theory and boundary traction method. The fault core is simulated as a discontinuous plane with interface elements at the center of the model, and fault-slip is induced by gradually reducing the effective normal stress on the fault plane. Seismic source parameters are computed and analyzed under various fracture stiffness conditions. Seismically radiated energy is defined as the work done by the stress perturbation across a closed surface at a distance from the earthquake source, while seismic moment is calculated using the moment tensor of a seismic source in an anisotropic medium. This study investigates increasing fracture stiffness while maintaining a normal-to-shear stiffness ratio of three. Dynamic analysis results reveal a notable impact of fracture stiffness on seismically radiated energy and seismic moment, both of which decrease significantly with increasing fracture stiffness. These findings imply the importance of considering fracture stiffness for more accurate estimation of seismically radiated energy and seismic moment.
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    item: Conference-Full-text
    Mineralogical classification and concentration estimation in mining with app using hyper-spectral imaging and machine learning
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Okada, N; Takizawa, K; Wakae, S,; Ohtomo, Y; Kawamura, Y; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    This study presents an innovative method for identifying minerals by combining the capabilities of hyperspectral imaging with machine learning. Although hyperspectral images are challenging to process due to their extensive dimensions and substantial size, our solution effectively tackles this complexity by providing a user-friendly machine learning tool specifically tailored for hyperspectral data. This self-developed tool simplifies the process of constructing datasets and enhances machine learning processes for identifying mineral species and estimating their concentrations. The interface is designed to be easy to use, allowing non-experts to effectively identify minerals without needing professional expertise. This is further enhanced by the integration of machine learning capabilities. Our instrument is positioned as an innovative solution that greatly enhances geological surveys in mining regions, leading to useful outcomes for mineral-related research and industrial applications.
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    item: Conference-Full-text
    A Study of groundwater recovery following tunnel construction in the upper highland complex – a case study on the Ranwediyawa tunnel
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Dissanayake, HM; Perumal, M; Lees, DJ; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    In Sri Lanka, understanding the hydrogeological conditions is vital when constructing tunnels, especially geological regions such as the Highland Complex, where groundwater supports local communities and agriculture. While some recent data sheds light on groundwater reduction during tunneling, little is known about the recovery process. The Ranwediyawa tunnel construction, part of the Mahaweli Water Security and Investment Program (MWSIP), offered an opportunity to monitor groundwater impact closely. During excavation, considering seasonal variations, a reduction in groundwater levels was recorded, and following tunnel completion and installation of the waterproof lining, the groundwater recovery was monitored. The hydrogeological conditions of the Highland Complex present unique challenges as groundwater is vital for local communities and agriculture, so tunneling activities must be carefully managed to minimize disturbance. This paper outlines the planning, monitoring, and construction carried out for this project. Our findings stress the importance of comprehensive planning and monitoring during tunnel construction, understanding hydrogeological conditions and implementing effective waterproofing measures, to minimize environmental impact and ensure no disruption in domestic water supply and agriculture sustainability. It is hoped that the data and insights gained from this project can be used in future tunnel projects in similar hydrogeological settings, enhancing infrastructure project resilience and safeguarding groundwater resources for future generations.
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    item: Conference-Full-text
    Incident of ground collapse up to daylight and recovery actions taken in shallow Ranwediyawa tunnel in Sri Lanka
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Perumal, M; Wanigasekara, WADID; Isuranga, SNAMTK; Narangoda, SRAIB; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    The Ranwediyawa tunnel was constructed under the Mahaweli Water Security Program (MWSIP) to minimize the social impacts on the villages, where the irrigation canal runs through the village. The tunnel was slightly redirected from the original canal path which was planned to run through the village road having a deep excavation over a length of 620m with a mixed ground condition. The area has a high ground water table and seasonally varies slightly due to the area's weather pattern with varying topography and which has a deep open excavation from 12m to 18m for the construction of cut & cover conduit. Having a shorter period of design the Ranwediyawa tunnel was designed with a ground cover varying from 9m to 20m, including 5 support classes according to the RMR classification. Both tunnel portals start with completely to slightly weathered rock and move into moderately weathered to fresh rock. Both tunnel drives were driven by mechanical excavation with NATM concept with few small chimney collapses, however, a major collapse occurred once the upstream drive reached the rock-type boundary and it was developed to daylight. This paper describes the details of the initial excavation procedures, the major geological conditions and the recovery procedures which were taken to complete the tunnel excavation. Also, this paper covers special arrangements made by the Contractor in the shortage of resources available in the project as the incident occurred during the spreading of the COVID-19 period. The tunnel drive successfully passed this weak geological area with long pipe roofing support before the tunnel excavation after two months with a few days of site closure due to the identified worker getting COVID-19 in the tunnel team.
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    item: Conference-Abstract
    Polymer-modified microbial induced carbonate precipitation for stabilizing unstable slope surfaces in Sri Lanka
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Chandraleka, K; Sabeshraj, P; Thilakarathna, AMGGG; Nawarathna, THK,; Gowthaman, S; De Silva, LIN; Karunawardena, A; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Cement grouting is a widely using technique in Sri Lanka to stabilize the unstable slope surfaces. Although cement grouting has been identified as an efficient mean of stabilization, it is not an ecofriendly practice. Polymer-modified microbial induced carbonate precipitation (PM-MICP) has been recently recognized as a promising pathway to produce bio-grout material that has the potential to be used for stabilizations in the place of cement. In MICP, calcium carbonate bio-cement is produced through enzymatic reactions. The efficiency of the process can be further improved by incorporating bio-polymer. In this research, the viability of the PM-MICP to stabilize the Sri Lankan unstable slope surfaces was evaluated. Representative soil samples were collected from unstable slope areas in Matale district of Sri Lanka. Sporosarcina pasteurii was the ureolytic bacteria, and chitosan was the natural biopolymer used for the experiments. Laboratory scaled specimens were prepared and treated using (i) saturation and (ii) percolation methods; for different concentrations of cementation solutions (i) 0.3 mol/L and (ii) 0.5 mol/L); (i) with 0.05% and (ii) without chitosan. Bacteria culture was injected twice during the fourteen days of treatment, while the cementation solution was injected daily. After the treatment, samples were removed from the mold and subjected to a comprehensive evaluation program. Laboratory-scale model slope was also prepared and treated after 28 days of treatment, and the surface strength was determined. The samples treated with 0.5 mol/L cementation solution and polymer, exhibited a strong solidification compared with the specimens treated without polymer in both saturation and percolation methods. However, bottom of samples showed a weak solidification due to the less penetration of the bacteria and cementation solution to the bottom of the sample. In without polymer case, a weak solidification was observed for the samples treated using percolation method compared with the saturation method. Higher cementation could be achieved for the samples with 0.5 mol/L cementation solution than the sample with 0.3 mol/L. Comparatively, the surface strength was higher for the slope treated with polymer, thus the PM-MICP can be recommended as a promising alternative approach to conventional cement grouting for stabilizing the unstable slope surfaces in Sri Lanka.
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    item: Conference-Abstract
    Isolation and characterization of ureolytic bacteria from landslide-prone areas in Sri Lanka for the stabilization of unstable slope surface by bio-cementation
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Srirajatheepan, R; Ducksan, S; Srirangan, S; Thilakarathna, AMGGG; Nawarathna, THK; Gowthaman, S; De Silva, LIN; Karunawardena, A; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Landslides are natural disaster, long-existing as one of the geotechnical threats in the central region of Sri Lanka. During the monsoon period of every year, number of human lives are lost due to the landslides. Therefore, early recognition of the potential areas and implementing landslide mitigative measure are essential to prevent the damages. Portland cement and chemical grouts are typically used to enable a protective cover over the slope surface. However, these approaches are recognized environmentally detrimental and expensive. The use of bio-grouting materials is a new proposal to stabilize the slope surface, disclosing the likelihood of eco-friendliness and sustainability. Among various bio-grouting techniques, microbial induced carbonate precipitation (MICP) has gained much attention recently. MICP is a process that triggers the precipitation of calcium carbonate using the metabolic aid of ureolytic bacteria. This paper presents the initial works carried out to isolate and characterize urease-producing bacteria that are competent for the application of MICP-based stabilization of Sri Lanka's unstable slopes. Few landslide-prone areas were identified in Matale district (of Sri Lanka) with the support of National Building and Research Organization. From each location, soil samples were obtained in sterile centrifuge tubes and transported to the laboratory. After a series dilution, soil samples were plated on trypticase soy broth agar medium and incubated at room temperature for two days. Grown-colonies were then carefully separated on new agar plates. Initial screening of potential bacteria was carried out using phenol red pH indicator. The growth and urease activity of identified bacteria were then measured over time. A set of test tube precipitation tests was also performed to verify the applicability of the bacteria. The results indicated that most of the identified bacteria exhibited adequate growth and urease activity during the second and third days of the culturing. The test tube test revealed that the natively-isolated bacteria were highly potential to produce CaCO3, thus disclosed the potential for MICP application. Based on the preliminary results, laboratory-scale slope model tests and field-trails are to be performed in the subsequent phase of this work.
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    item: Conference-Full-text
    Investigation of suitable methods to protect main roads adjacent to water bodies
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Logeswaran, J; Kulathilaka, SAS; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Main roads near water bodies are prone to stability issues caused by erosion from rainfall, river flow, sudden water drawdowns, and human activities. This study examines four sites facing such challenges, identifying erosion causes and evaluating stabilization methods. Techniques such as gabion walls, bamboo crib walls, and vegetated soil bags were explored, balancing cost, constructability, and sustainability. Implemented solutions have shown promising performance, supporting eco-friendly infrastructure initiatives. The findings demonstrate the potential of combining conventional and bioengineering methods for effective slope stabilization. This research contributes to the advancement of sustainable practices for protecting road infrastructure, crucial for future applications in similar geotechnical conditions in Sri Lanka.
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    item: Conference-Full-text
    Optimization of rice straw hydrolysis to convert ligno-cellulose to simple sugars
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Madanayake, N; Basnayake, BFA; Jayakody, LN; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Development and use of renewable energy is a key option towards poverty alleviation and to mitigate global warming. Annual rice straw yield of 2.7 million metric tons in Sri Lanka is the most abundant lingo-cellulosic crop residue for bioconversion into ethanol. This research focused on the hydrolysis phase in ethanol production to optimize the rice straw digestion in the saccharification process. In this study, four anaerobic leaching columns in which the base filled with gravel and sand were used. Except for the control, the other three contained an additional soil layer of 60 mm that was obtained beneath a pile of decomposing rice straw. Then, 500g of rice straw was added to each column. In one of the soil added columns, elute was re-circulated. Rice straw to water ratio was maintained at 1:20 by adding water and straw. Samples were taken at daily basis, except for non-recycled one with analysis of initial and final day for pH, conductivity, TDS, salinity, brix, TS, VS, VSS, TSS, VSS, and BOD. The non-recycled, soil added column gave increased values of conductivity, TDS, salinity, TSS, VSS, and well-grown white mycelia on straw. Highest values of measured parameters were reported in re-circulated column. The increment of cumulative conductivity, TDS, salinity, VS, TSS, and VSS, of non-recycled, soil added column was significant rather than the control. In applying Michaelis Menten kinetics, Vmax and Km for the column without soil are 0.33 and 26.7, with soil were 0.42 and 18.37 and with re-circulation were 7.22 and 0.15, respectively. The latter with higher rate of conversion with less inhibition, proved better affinity between substrate and enzyme. The elusions of TS for without and with soil were 58.0g and 71.5g. These converted to 40.1g and 50.8g of simple sugars and they were 8.0% and 10.1% of total straw weight, expressing in cellulose mass, varied between 22.9%-26.7% and 29%-33.8% of simple sugars. Thus, deduced energy contents are 1.03-1.40 MJ/kg and 1.30-1.77 MJ/kg. Hence hydrolysis of rice straw with soil, has a potential to recover 175 million liters of ethanol.
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    item: Conference-Abstract
    A Preliminary evaluation of river sediment load: a case study of Maha oya river in the western coast of Sri Lanka
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Jayathilaka, RMRM; Ratnayake, NP; Wijayaratna, TMN; Silva, KBA; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Rivers have a significant role in the coastal sediment budget as the primary sources of natural sediment. Furthermore, it's critical to understand the actual contribution of river sediment load to the littoral beach. Due to the practicality of the measures, the information regarding river measurements is scarce making this difficult. This study focused on the Maha Oya River, which is situated on a severely eroding coastline on Sri Lanka's western coast between Negombo and Chilaw. In this instance, the river sediment load was captured by two streamer-type sediment traps along the upper 2 km streams of the Maha Oya River, but only one of them was recovered. The sediment trap was retrieved for the months of December 2021–February 2022 (recovery 1) and March 2022–October 2022 (recovery 2). During two recovery periods, we concurrently collected forty-four beach samples from the swash zone and berm crest on either side of the Maha Oya River. For recovery periods one and two, the retained sediment weights are 3.7 and 726 grams, respectively. Additionally, the statistical properties of a grain size distribution, skewness, kurtosis, median grain size (D50) and the littoral cutoff diameter (LCD) value were investigated. Average D50 value on the beach was found to be 394 μm of medium sand that was moderately sorted, symmetrical, and mesokurtic, compared to 655 μm of coarse sand that was poorly sorted, fine skewed, and mesokurtic in river sediment. The LCD value on the beach under study was 141 μm indicating that the river sediment below LCD may not have remained on the beach in any significant quantity. The literature states that river sand mining caused the sediment load via the Maha Oya River to decrease from 0.15 mcm/year in 1984 to 0.05 mcm/year in 2001. Our calculations show that in 2022, this number will be further decreased to 0.01 mcm/year. Thus, it is highlighted that there is a major shortage of river sand input into the coast, which may be the cause of the disastrous erosion occurring in the surrounding coastal cells.
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    Assessing the influence of microstructural features on deformation of rocks under triaxial loading
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Silva, SAV; Rathnapriya, RHDL; Riyasath, MSM; Dassanayake, ABN; Fujii., Y; Wickrama, MADMG; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Assessing the influence of microstructural features on the deformation of rocks under triaxial loading is vital in rock engineering applications, aiding safe and efficient operations by predicting the deformation of rocks. Triaxial testing offers the simulation of stress conditions within a rock to examine the deformation of rocks with confinements. This research focuses on how microstructural features, such as cementing material and pore geometry, affect the deformation behaviour of rocks subjected to triaxial loading. Two rock types were considered in this study: Kimachi sandstone (medium hard clastic rock) and Bibai sandstone (hard clastic rock). The progressive failure behaviour under Hydro Mechanical (HM) coupling effect was analysed by stress-strain distribution and the fracture geometry was examined using CT images of the specimens which were tested under different confinements. Thin sections were analysed to examine the changes in porosity and the effect on the cementing material with the confinement. The results of the proposed approach reveal a clear influence of the effective confinement on the failure of rocks and how it influences the porosity and cementing material of rocks. It is found that the Bibai sandstone shows a brittle failure and a shearing deformation while Kimachi sandstone shows a brittle to ductile failure and shearing to compaction deformation with the confinement due to the less presence of cementing material within Bibai sandstone compared to Kimachi sandstone. Therefore, with the confinement, the porosity of Bibai sandstone increases while it decreases in Kimachi sandstone. The results highlight the differences in the failure mechanism of a particular rock type for the same effective confinement which is a result of only a partial contribution of the pore pressure on the failure. These findings provide valuable insight into the assessment of microstructural features on the deformation of rocks under triaxial loading, aiding in the development of safer and more efficient rock engineering operations.
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    Identification of the optimum replacement ratio of quarry dust as a substitute for sand and cement in cement plastering
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Dhananjaya, MMP; Gajanan, P; Bandara, RGTI; Illankoon, IMTN; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    River sand and cement are important construction materials, but their scarcity creates significant challenges for the construction industry. Quarry dust is being explored as a possible alternative, as crushed rock is a common aggregate source in Sri Lanka. Therefore, this study focuses on determining the possibility of using quarry dust as a partial replacement for cement and river sand in plastering mortar. Selected Manampitiya river sand and quarry dust from four quarries were subjected to sieve analysis (ASTM C136). Four quarry dust samples obtained from two different crusher types (cone crusher and vertical shaft impact crusher) were sieved to separate 0.1-2.36 mm particles and <0.1 mm particles to replace with sand and cement, respectively. Plastering mortar’s cement-sand ratio was selected as 1:5 and developed in 12 mix proportions, varying the replacement of sand with quarry dust (0.1-2.36 mm particles) at 0%, 33%, 50% and 100%, as well as the replacement of cement with quarry dust (<0.1 mm particles) at 0%, 5% and 10%. The flow table test (ASTM C1437) was performed for each mix proportion to obtain the water-cement ratio of plastering mortar, which gives acceptable workability (105-115 mm). Four 50 mm cubic specimens from each mix proportion were prepared according to the obtained water-cement ratio. The cubic compression test (ASTM C109M) and water absorption test (ASTM C140) were performed for the cubic specimens after the completion of the 28-day curing period. Results indicate that the sand and quarry dust samples analysed are poorly graded. An increase in quarry dust in the plastering mortar reduced the workability, but it reached an acceptable range with a water-cement ratio of 1.1-1.2. All tested specimens indicate compressive strength >3 MPa, which was the minimum strength required for plastering. The compressive strength results indicate that the cement replacement can be further increased with 100% sand replacement. The durability of plaster slightly reduces with an increase in quarry dust proportion, indicating a maximum of 2.4% increment in water absorption for a 100% sand-replaced, 10% cement-replaced specimen compared to a specimen made from 100% sand. Furthermore, 100% sand replacement can achieve a cost reduction of 27%. Hence, it is recommended to replace sand 100% with quarry dust 0.1-2.36 mm particles for cement plastering.
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    item: Conference-Abstract
    Evaluation of satellite-derived gravity field models in offshore and coastal regions of Sri Lanka
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Wijesooriya, WMARK; Prasanna, HMI; Gunathilaka, MDEK; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    To understand many geophysical phenomena, including ocean circulation, tectonic plate movement, and the Earth’s interior, it is important to study the Earth’s gravity field. During the past three decades, satellites have measured the Earth’s static gravity. As a result, high-resolution global gravity field models have been available. This paper aims to examine the appropriateness of the satellite derived gravity field models for the offshore and coastal regions of Sri Lanka.While these eight gravity field models with ID 155-EIGEN-6S4 V2, 168-Tongji-Grace 02K, 171-GO-CONS-GCF2-TIM-R6, 174-ITSG-GRACE 2018S, 178-Tongji-GMMG2021S, 148-EIGN-6C4, 152-GECO, 167-SGG-UGM-1, and 177-SGG-UGM2 were used for the study. The mean difference value, standard deviation value, and Root Mean Square values modeled by each of the model between the observed gravity data and the BGI observed gravity data. The results indicated that 171-GO-CONS-GCF2-TIM-R6 and 177-SGG-UGM2 is the more suited model for the coastal and offshore region of Sri Lanka. The study used the SARAL-Altika satellite Altimetry data to investigate the relationship between Mean see surface height and observed gravity. No significant relationship between Mean sea surface height and marine gravity is indicated by. In addition, the influence of gravity model type on each of the LEO satellite orbit predictions was also studied. The findings of the research demonstrate that the optimal type of gravity model applied for LEO satellite orbit prediction depends on a short-term or long-term predictions. The models JGM3, EGM2008, and GL04C are more appropriate for short-term predictions, while the models JGM3, EGM96, and EIGEN2 are the best for long-term predictions. The gravity order and permanent tides also have to be taken into account for the orbital prediction.In conclusion, this research provides valuable insights into the suitability of various satellite-derived gravity field models for Sri Lanka's coastal and offshore regions. The findings also emphasize the need to consider the impact of gravity models on LEO satellite orbit prediction, particularly for new applications such as LEO navigation, which require real-time precise orbits.
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    item: Conference-Abstract
    Comparative analysis of mechanical and mineralogical properties of rocks from maddhapara granite mine, Bangladesh
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Alam, A.M.K.B.; Fujii, Y.; Dipu, N.H.; Ghalib, F.H.; Sajib, A.I.; Ullah, A.S.M.W.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
    This study presents a comprehensive analysis of the mechanical and mineralogical properties of rocks collected from Maddhapara Granite Mine (MGM) in the northern region of Bangladesh. The research focuses on the characterization of two main categories of rocks, distinguished by their color and mineral composition, namely the dominant black rock and the flashy colored rock. Microscopic studies were conducted to categorize the rocks, leading to the identification of minerals such as quartz, feldspar, amphibole, and biotite within the rock samples. The black rock was classified as Tonalite, with specific mineral compositions, while the flashy colored rock was identified as granite, exhibiting distinct mineral proportions. The research further delves into the physical properties of the rocks, including density, effective porosity, P-wave velocity, S-wave velocity, and Uniaxial Compressive Strength (UCS). Notably, UCS tests were performed to characterize stress parameters such as crack closure stress, crack initiation stress, crack damage stress, and peak stress for both rock types. The results revealed significant differences in stress levels and mechanical responses between the two rock types, with tonalite exhibiting higher stress levels and distinct mechanical behaviors such as plastic deformation and shear deformation, compared to the granite. These variations are attributed to the dominating minerals present in each rock type, particularly amphibole and quartz for tonalite, and feldspar and quartz for granite. The findings of this study have implications for the stability of drifts and stopes in mining operations, as the mechanical responses of the rocks, influenced by their mineralogical composition, may impact their suitability for various engineering applications. This research contributes to the understanding of rock properties in the context of mining engineering, providing valuable insights for the assessment and utilization of rocks from MGM and similar geological formations.
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    Assessment of biodiesel production potential and capacity analysis utilizing animal fat waste
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Upamali, W..M.A.; Wijesekara, E.R.J.M.D.D.P.; Amarasinghe, A.M.P.C.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
    New Anthony's Farm, a major chicken producer in Sri Lanka, generates significant wastewater during production. This study aims to find a solution for the sludge produced in their treatment plant. Animal fats, a common waste in various industries, require expensive treatment due to environmental regulations. They mainly consist of triglycerides (90-95%), which are further made up of fatty acids like saturated (SFAs), monounsaturated (MUFAs), and polyunsaturated (PUFAs). Animal fat waste offers valuable opportunities for industrial use, but its improper disposal poses significant environmental threats. Sustainable management and utilization of this waste are crucial to protect the environment and extract valuable resources. First, an FFA (Free Fatty Acids) test was done for the top and bottom animal waste fat samples taken from the fat separation Dissolved Air Floating unit in the wastewater treatment plant in 'Anthony's Farm. The NaOH base with the Phenolphthalein indicator titration method was used for this FFA identification. After that, acid treatment was performed to reduce the FFA value of these samples, 60 0C hot water washing was done to purify the animal waste fat sample, and biodiesel was produced by transesterification. Direct transesterification was not obtained for the bottom sample, so the resulting liquid layer was centrifuged at 3000 rpm for 15 minutes and trans-esterified. After that, both samples were used to produce bioethanol. There, the top sample was directly used for bioethanol production without pretreatment, and bioethanol was produced using the glycerol layer of the bottom sample. The acid treatment was done with an H2SO4 Acid-to-fat ratio of 12:1, Temperature around 64°C, and pH - around 7, and it was reduced the FFA value of the top sample from 20.72% to 12.60%, and the initial FFA value of the bottom sample, which was 3.36%, was reduced to 2.80%. Considering this FFA value, the bottom sample seems to have more potential for biodiesel production. Also, the flash point of the biodiesel produced in this way was measured using the Flashpoint analyser, and it was found to be 55.5 0C.
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    Distillery spent wash as an alternative fuel in boilers and potash recovery from that ash remaining in boilers
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Warnakulasooriya, G.A.P.K.G.G.; Amarasinghe, A.M.P.C.; Lankathilake, L.J.M.U.; Wijesekara, E.R.J.M.D.D.P.; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Waste management stands as a critical global environmental challenge, with a growing emphasis on waste avoidance and the generation of revenue through byproduct recovery. Pollution prevention strategies aim to minimize waste generation, while waste minimization efforts focus on reducing waste volume or toxicity, often through water recycling, process modification, and byproduct recovery. In this context, the utilization of distillery effluent in agriculture presents an opportunity to save on fertilizer costs, enhance agricultural output, and mitigate pollution. However, molasses-based distilleries, along with their primary product, alcohol, generate significant volumes of wastewater known as spent wash. Improper disposal of spent wash into water bodies or land leads to a host of environmental issues. Consequently, recent efforts have shifted towards waste minimization and revenue generation through byproduct recovery. This study focuses an approach to address the challenge of distillery spent wash management by drying the spent wash and utilizing the resulting dried solids as an alternative fuel for boilers. The distillery spent wash contains approximately 14.6% solid content, and the dried solids have a gross calorific value of 13840 J/g. Furthermore, the dried solids possess an ash content of 2.26%, with the ash containing a notable 36.7% potassium oxide content. By transforming distillery spent wash into a valuable resource for boiler fuel, this research not only addresses waste management concerns but also offers a sustainable solution for revenue generation. The utilization of dried solids as an alternative fuel for boilers contributes to reducing environmental pollution associated with improper spent wash disposal while offering a viable source of renewable energy. This study underscores the potential of waste-to-energy initiatives in fostering sustainable waste management practices and enhancing economic viability in the distillery sector.
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    item: Conference-Abstract
    Enhancing concrete sustainability through carbonated recycled cement powder: a review
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Mylvaganam, N; Yogarajah, E; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
    Concrete is a vital construction material, but the rapid urbanization has led to a significant accumulation of demolished concrete, especially in developing countries. Despite efforts, only a small fraction of this concrete is recycled, leading to environmental challenges. However, countries like Japan have successfully recycled a large portion of their demolished concrete, primarily for use in road subbase and as Recycled concrete aggregate (RCA) which is typically yields lower quality compared to natural aggregate (NA). Additionally, during RCA production, a significant amount of cement powder is generated, which has the potential to be used as a supplementary cementitious material (SCM). Recent research has explored various valorisation methods for recycled cement powder (RCP), with carbonation emerging as the most sustainable option. Carbonated RCP not only stores CO2 but also improves concrete properties such as compressive strength and durability. Considering the environmental impact of traditional cement manufacturing, the utilization of SCMs, such as carbonated recycled cement powder (cRCP), has emerged as a promising strategy. This approach promotes sustainable recycling practices and contributes to ecological conservation efforts, aligning with the circular economy philosophy. This review highlights recent findings on the accelerated carbonation treatment of RCP, exploring its benefits and applications as a sustainable building material
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    Comparative analysis of vertical metal zonation in Ginigalpelessa and Indikolapelessa serpentinite complex
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Mahendran, M; Maduranga, U.K.D.; Amarasinghe, A.A.Y.D.T.; Abeysinghe, A.M.K.B.; Ratnayake, N.P.; Premasiri, H.M.R.; Dushyantha, N.P.; Batapola, N.M.; Dilshara, R.M.P.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A.; Jayawardena, C.
    Serpentinite deposits in Ginigalpelessa and Indikolapelessa Sri Lanka, are known to exhibit a high supergene enrichment of Ni, Cr, and Co in the regolith due to the prolonged weathering of the underlying serpentinite bedrock. However, no detailed studies have been conducted to determine the vertical zonation of these critical metals in these deposits. The vertical metal distribution of a deposit is significant to delineate its vertical metal enrichment patterns and mobilization which may lead to the identification of efficient exploration and extraction methods. Therefore, this study assessed the vertical zonation of Ni, Cr, and Co in both Ginigalpelessa and Indikolapelessa serpentinite deposits. Twenty-four soil (n=12) and weathered rock (n=12) samples from 4 soil horizons (O, A, B, C) in soil profile were collected and analyzed for Ni, Co, Cr, and Cu by ICP-MS. Our findings revealed high metal concentrations in the soil or highly weathered rock samples over the partially weathered rock samples. The Ginigalpelessa deposit demonstrated4 a higher concentration of Ni, Co, Cr, and Cu compared to the Indikolapelessa deposit. It observed that the concentrations of Ni, Co, Cr and Cu in the topsoil were lower compared to deeper horizons (A, B, and C) in some locations. This may have occurred due to the bioavailability of some metals like Ni, which accumulates in the plants and reduce the concentration in the soil. Conversely, the low bioavailability of Cr compared to the other metals have resulted high Cr concentrations in the surface horizon. In addition, previous studies found that Cr is immobile, whereas Ni and Co are scarcely mobile under the moderate acidic conditions in the serpentine soil. During the weathering process, the slightly acidic rainwater leaches these Ni-like metals from the O and A horizons, resulting their enrichment in the B horizon. However, further studies are necessary to identify the suitable leaching or extraction method to recover these metals from serpentine soil. Therefore, this research contributes to a deeper understanding of vertical metal zonation in serpentinite deposits to facilitate more efficient and sustainable exploration of valuable metals like Ni in serpentinite deposits.
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    Assessing the applicability of geophysical methods for exploring vein type mica deposits – a case study in Matale district, Sri Lanka
    (Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Wickramasinghe, K.G.K.G.; Arachchige, R.A.N.U.R.; De Zoysa, D.Y..B.; Premasiri, H.M.R.; Abeysinghe, A.M.K.B.; Ratnayake, N.P.; Batapola, N.M.; Dilshara, R.M.P.; Iresha, H.; Elakneswaran, Y.; Dassanayake, A; Jayawardena, C
    Mica, a group of silicate minerals characterized by their layered structure, is integral in various industries due to its insulating properties, heat resistance, and aesthetic appeal. Mica is commonly found as pegmatite and vein type deposits. However, vein type mica is extremely difficult to explore because of the complexity of their underlying geology and structural features. Atipola mica mine is one of the well-known mica mining sites in Matale district, Sri Lanka where the exploration of vein type mica deposits is difficult due to their complex geological formation. Therefore, this work attempts to assess the applicability of the Ground Penetrating Radar (GPR) geophysical methods for discovering new mica deposits. The field survey data collecting, and coverage plan were developed to investigate the most appropriate and pertinent area based on preliminary field observations. Since mica mining has emerged as a crucial economic activity in Sri Lanka, this study will also contribute to the investigation and advancement of vein-type mineral deposit exploration in Sri Lanka. Integrating GPR could make it possible to explain the subsurface structure in a non-destructive and appropriate way, which could help with informed mining methods and lead to the right decision regarding the accurate categories of the mineralogy deposit