Browsing by Author "Herath, B"

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item: Conference Full-text
Application of emulsion explosive and comparative study on water-gel explosives for rock quarrying in Sri Lanka
Dharmaratne, PGR; Hemalal, PVA; Rohitha, LPS; Herath, B; ; Abeysinghe, AMKB; Dassanayake, ABN; Elakneswaran, Y
Dynamite has been the premier and the only high explosive used for mining and construction activities in Sri Lanka for a long period of time. Negative environmental impacts, effect on health and security hazards led to the Government of Sri Lanka (GOSL) to issue directives to find a suitable substitute for Dynamite. Subsequently, Water-Gel explosive was introduced in the year 2011. The poor performance of Water-Gels in wet conditions and it’s low Velocity of Detonation encouraged the use of Emulsion explosives. This research was focused on performing a comparative study of the performance of both Water-Gels and Emulsion explosives by analysis of the ground vibration and the blast air over pressures. The methodology adopted was to conduct ten blasts at one single metal quarry site keeping all other parameters constant. Blasting tests were performed using Emulsion explosives and Water-Gel explosives and the resulting ground vibration and Air-Blast overpressures were measured with Blastmate 111model for each blast. Calculation of mean fragmentation was done and particle size distribution based on photographic evidence of each blast was analyzed. Analysis was carried out demarcating the resultant production pile of aggregates covering a cleared zone. Grid lines inserted on the muck pile facilitated particle counting using photographs and calculating the mean fragmentation.
item: Thesis-Full-text
Comparative study of emulsion and water gel explosives for rock quarrying
Herath, B; Hemalal, VPA; Dhramarathna, PGR; Rohitha, LPS
In the mining field, blasting is the predominant method for breaking of consolidated rocks and the main objectives are to extract the large quantity at both minimum cost and having minimum damage to the environment. Rock breaking , over the years , which was limited to just breaking of boulders for the use of building and road construction has developed vastly to various aspects of mining namely ,open cast, underground and underwater blasting. Manually drilled single shot bore holes are disappearing and making way to multiple bore holes of immense depth with the introduction of the latest blasting technologies. Result of the introduction of optimum blasting techniques and sustainable development criteria, mining industry has twisted in the path of eco-friendly mining. Explosives and blasting techniques that are used nowadays are based on the above concept. Use of Dynamite changed to lesser powerful explosives such as Water Gel and then to Emulsion explosives. Our country also discarded the use of Dynamite several years ago and Water Gel explosives was introduced. Water Gel explosives is eco friendlier than Dynamite but could not be substituted in areas underground and underwater blasting. Introduction of Emulsion explosives was mainly to overcome these disadvantages of Water Gel Explosives. Aim of this study is to carry out a comparative study in all areas of open cast mining and to ascertain the most appropriate high explosive type for optimum output.
item: Article-Full-text
Design and development of a novel oral care simulator for the training of nurses
(IEE, 2020) Herath, B; Dewmin, GHS; Sukumaran, S; Amarasinghe, YWR; De Silva, AHTE; Mitani, A; Wijethunge, D; Sampath, WHP
Objective: A Novel Oral Care Simulator was designed and developed to measure and visualise the facial and lingual forces exerted on teeth by the action of tooth brushing, considering the irregular geometry and structural composition of human dentition and the emulation of the realistic biomechanical deflection of the teeth. Method: FEA simulations were carried out on a central incisor under facial loading and an appropriate force sensing mechanism was designed. An anatomically accurate mandibular jaw and 16 teeth were 3D printed, on which 16 force sensing structures were embedded. The signals from the sensors were amplified using a multichannel signal amplifier built using instrumentation amplifiers which were then visualised through a GUI. Results: The developed simulator is capable of indicating the magnitude of a force upto 15 N exerted on to the facial and lingual surfaces of teeth at a frequency of 60 Hz and above and it is capable of alerting the user if the force exceeds a pre-specified threshold. Conclusion: The designed force sensing mechanism considers the irregular geometry and structural composition of human dentition in measuring the facial and lingual forces. It provides a reliable feedback by indicating the force and emulating the realistic biomechanical deflection of teeth. Significance: Nurses who care for the disabled, elderly and sick have explicitly stated the requirement for a simulator to train themselves on brushing the teeth of their subjects as their incorrect technique can cause longterm dental damage, for which a device has not been developed to date.