http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/112 Tue, 07 Apr 2026 11:31:09 GMT 2026-04-07T11:31:09Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9957 QuantifyingtheImpactofUncertainMaterialParametersonPavement ResponseusinganInverseModellingTechnique P, Kathirgamanathan; M, Vignarajah Accuratemodellingofpavementresponseplaysacriticalroleintheeffectivedesign, analysis,andmaintenanceofroadinfrastructure.However,thepresenceofuncertainty inmaterialparameterscansignificantlycompromisethereliabilityandaccuracyofsuch models.Thisstudyfocusesoninvestigatingtheimpactofuncertainmaterialparameters onpavementresponsebyemployinganinversemodellingtechnique.Theobjectiveofthis researchistoutilizeaninversemodellingapproachtoassesstheinfluenceofuncertain materialparametersonUzan’smodel,acommonlyusedmodelforpavementresponse. ThestudyconsidersmeasuredstressandstrainvaluesobtainedfromtyreandFalling WeightDeflectometerloadconditionsappliedtogranularmaterials.Theinversemodel isformulatedasanonlinearleastsquaresminimizationproblem,inconjunctionwith afiniteelementmodelthatanalysesthedeformationofflexiblepavements.Through theapplicationoftheinversemodellingtechnique,thisstudyaimstodeterminethe extenttowhichuncertainmaterialparametersaffecttheaccuracyofpavementresponse predictions.Bycomparingthepredictedpavementbehaviourderivedfromtheinverse modelwithactualmeasureddata,theinfluenceofuncertainparameterscanbequantified. Theoutcomesofthisresearchcontributetoadvancingtheunderstandingofthecomplex interplaybetweenmaterialparameteruncertaintiesandpavementresponse. Sun, 01 Jan 2023 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9957 2023-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9187 Hydrogen Effect on the Mobility of Edge Dislocation in α-Iron: A Long-Timescale Molecular Dynamics Simulation Ryosuke, M.; Sunday, T.O.; Mugilgeethan, V.; Shinya, T. Explaining the hydrogen effect on dislocation mobility is crucial to revealing the mechanisms of hydrogen-related fracture phenomena. According to the general perspective, reducing the speed of dislocation can give enough time to hydrogen to catch up with the dislocation migration. In this research, we conducted molecular dynamics (MD) simulations to investigate the impact of hydrogen on the edge-dislocation motion in α-iron at various dislocation speeds and temperatures. It was discovered that, for all hydrogen concentrations evaluated in this paper, the hydrogen effect on dislocation transition from pinning to dragging occurs at a dislocation speed of around 0.1 m/s at 300 K. When the dislocation velocity is reduced to 0.01 m/s employing long timescale MD simulations over 1 μs, it is observed that hydrogen follows dislocation motion with small jumps in the dislocation core. The required stress to migrate the edge dislocation at a speed of 0.01 m/s was discovered to be 400 MPa, even at a lower hydrogen concentration, which was achieved in a gaseous hydrogen environment with lower pressure than atmospheric pressure. Although the dislocation still traps hydrogen at 500 K, as temperature increases, the impact of hydrogen on the shear stress required for dislocation glide becomes negligibly small. The required shear stress at lower dislocation speeds was predicted by employing the stress-dependent thermal activation model assuming the hydrogen diffusion rate-determining. The finding demonstrated that the edge dislocation should slow down until 1 mm/s order or less in the presence of hydrogen and suitable stress for α-iron. Sat, 01 Jan 2022 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9187 2022-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9178 Traffic Occupancy Prediction Using a Nonlinear Autoregressive Exogenous Neural Network Khaleel, N.I.; Anuraj, U.; Hartley, J. The main aim of intelligent transportation systems is the ability to accurately predict traffic characteristics like traffic occupancy, speed, flow, and accident based on historic and real-time data collected by these systems in transportation networks. The main challenge of a huge quantity of traffic data collected automatically, stored, and processed by these systems is the way of handling and extracting the required traffic data to formulate the prediction traffic characteristic model. In this research, the required traffic data of a specified road link in the UK are extracted from the big raw data of the Split, Cycle, and Offset Optimization Technique (SCOOT) system by designing a C++ extractor program. In addition, short-term traffic prediction models are created by using a deep learning technique called a Nonlinear Autoregressive Exogenous (NARX) neural network to find accurate and exact traffic occupancy. Three scenarios of time intervals which are 10 minutes, 20 minutes, and 30 minutes are considered for analyzing the prediction accuracy. The results showed that the prediction models for the 30 minutes interval scenario have very good accuracy in estimating the future traffic occupancy compared to other scenarios of time intervals. In addition, the testing and validation study showed that the prediction models for 30 minutes intervals for particular road link yield better accuracy than 10 minutes and 20 minutes intervals. Sat, 01 Jan 2022 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/9178 2022-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8647 A novel 3 -D printed wrist powered upper limb prosthesis using whippletree mechanism Kumarage, K.P.L.; Wickramarathan, W.H.S.; Madhushan, V.; Mugilgeethan, V.; Neethan, R.; Thanihaichelvan, T. This study focuses on the development of a 3-D printed low-cost novel solution for upper limb amputees in Sri Lanka. Prosthetic devices available in Sri Lanka are declined by most patients with trans-metacarpal amputation due to the high cost and discomfort. Worldwide the 3-D printing technology has been recognized as a convenient solution for prostheses owing to its customizability and low cost. The adaptive grasp functionality in mechanical prostheses is important to effectively utilize the limited angle of the wrist. Wrist motion of healthy individuals and the limitations in wrist flexion occurring after amputation were studied. With the findings, a novel design was developed incorporating a modified whippletree mechanism. The prosthesis was printed and tested for adaptive grasp and comfort. In this testing, whippletree mechanism was used to improve the adaptive grasp through proper force distribution and a flexible material was introduced for wearable comfort. It was found that this kind of prosthetic hands will help the amputee to grasp complex shaped objects while providing good comfort Tue, 01 Jan 2019 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8647 2019-01-01T00:00:00Z