The Experts below are selected from a list of 13263 Experts worldwide ranked by ideXlab platform
S Chatterjee - One of the best experts on this subject based on the ideXlab platform.
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influence of tuning of passive tld on the seismic vibration control of elevated water Tanks under various Tank full Conditions
Structural Control & Health Monitoring, 2017Co-Authors: Aparna Ghosh, S ChatterjeeAbstract:Summary This paper focuses on the seismic vibration control of elevated water Tanks (EWTs) by the passive tuned liquid damper (TLD). Because of the fluctuating water content, the EWT is a variable-mass system resulting in a continual modification of its natural frequencies. The problem of identifying the optimal tuning of the damper for robust performance over the range of fill depths of interest in the EWT is addressed here. The nonlinear model based on shallow water wave theory simulating sloshing motion of the liquid (here water) in the TLD is utilized. The sloshing of water in the EWT itself is considered by modeling the EWT as a two-degree-of-freedom system, one representing the lateral vibrational mode of the supporting Tank structure, Tank container and impulsive mass of the water and the other denoting the fundamental sloshing mode of the water. A time domain study on a realistic reinforced concrete shaft supported EWT with TLD subjected to harmonic and recorded accelerogram input indicates that the TLD achieves significant response reduction and that it should be tuned to the structural frequency corresponding to the half-full to three-fourth full Tank Condition for robust performance. Copyright © 2016 John Wiley & Sons, Ltd.
Sung-cheol Kim - One of the best experts on this subject based on the ideXlab platform.
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Preventive Maintenance Topic Models for LNG Containment Systems of LNG Marine Carriers Using Dock Specifications
MDPI AG, 2019Co-Authors: Ik-hyun Youn, Sung-cheol KimAbstract:The high demand for liquefied natural gas (LNG) requires more LNG carriers (LNGCs) to be in operation. During transportation, there is a high risk due to the required extremely low temperatures and the explosive nature of LNG cargo. Moreover, when there is a lack of experience in operating old LNGCs, there is a serious concern regarding operational accidents. A systematic maintenance strategy, especially for LNG cargo containment systems, is crucial for maintaining safe LNG transportation at sea. The purpose of this study is to develop preventive LNG cargo containment system maintenance models by using LNGC dock specifications from LNGCs of various ages. The dock specifications from a conventional LNGC repairing dock were analyzed using natural language processing techniques in order to develop preventive maintenance models of the LNG cargo containment system. From these results, and by considering the ship’s age, it was found that for young LNGCs, the priority for repair should focus on checking routine consumable spare parts by Tank inspections, whereas for older LNGCs, the focus should be on Tank Condition maintenance rather than on other facilities. These results are expected to be useful in the development of a maintenance strategy of preventive LNG cargo containment systems in maritime LNG transportation
Aparna Ghosh - One of the best experts on this subject based on the ideXlab platform.
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influence of tuning of passive tld on the seismic vibration control of elevated water Tanks under various Tank full Conditions
Structural Control & Health Monitoring, 2017Co-Authors: Aparna Ghosh, S ChatterjeeAbstract:Summary This paper focuses on the seismic vibration control of elevated water Tanks (EWTs) by the passive tuned liquid damper (TLD). Because of the fluctuating water content, the EWT is a variable-mass system resulting in a continual modification of its natural frequencies. The problem of identifying the optimal tuning of the damper for robust performance over the range of fill depths of interest in the EWT is addressed here. The nonlinear model based on shallow water wave theory simulating sloshing motion of the liquid (here water) in the TLD is utilized. The sloshing of water in the EWT itself is considered by modeling the EWT as a two-degree-of-freedom system, one representing the lateral vibrational mode of the supporting Tank structure, Tank container and impulsive mass of the water and the other denoting the fundamental sloshing mode of the water. A time domain study on a realistic reinforced concrete shaft supported EWT with TLD subjected to harmonic and recorded accelerogram input indicates that the TLD achieves significant response reduction and that it should be tuned to the structural frequency corresponding to the half-full to three-fourth full Tank Condition for robust performance. Copyright © 2016 John Wiley & Sons, Ltd.
Ik-hyun Youn - One of the best experts on this subject based on the ideXlab platform.
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Preventive Maintenance Topic Models for LNG Containment Systems of LNG Marine Carriers Using Dock Specifications
MDPI AG, 2019Co-Authors: Ik-hyun Youn, Sung-cheol KimAbstract:The high demand for liquefied natural gas (LNG) requires more LNG carriers (LNGCs) to be in operation. During transportation, there is a high risk due to the required extremely low temperatures and the explosive nature of LNG cargo. Moreover, when there is a lack of experience in operating old LNGCs, there is a serious concern regarding operational accidents. A systematic maintenance strategy, especially for LNG cargo containment systems, is crucial for maintaining safe LNG transportation at sea. The purpose of this study is to develop preventive LNG cargo containment system maintenance models by using LNGC dock specifications from LNGCs of various ages. The dock specifications from a conventional LNGC repairing dock were analyzed using natural language processing techniques in order to develop preventive maintenance models of the LNG cargo containment system. From these results, and by considering the ship’s age, it was found that for young LNGCs, the priority for repair should focus on checking routine consumable spare parts by Tank inspections, whereas for older LNGCs, the focus should be on Tank Condition maintenance rather than on other facilities. These results are expected to be useful in the development of a maintenance strategy of preventive LNG cargo containment systems in maritime LNG transportation
Marc Stutter - One of the best experts on this subject based on the ideXlab platform.
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Septic Tank discharges as multi-pollutant hotspots in catchments.
The Science of the total environment, 2015Co-Authors: Samia Richards, Eric Paterson, Paul J. A. Withers, Marc StutterAbstract:Small point sources of pollutants such as septic Tanks are recognised as significant contributors to streams' pathogen and nutrient loadings, however there is little data in the UK on which to judge the potential risks that septic Tank effluents (STEs) pose to water quality and human health. We present the first comprehensive analysis of STE to help assess multi-pollutant characteristics, management-related risk factors and potential tracers that might be used to identify STE sources. Thirty-two septic Tank effluents from residential households located in North East of Scotland were sampled along with adjacent stream waters. Biological, physical, chemical and fluorescence characterisation was coupled with information on system age, design, type of Tank, Tank management and number of users. Biological characterisation revealed that total coliforms and Escherichia coli (E. coli) concentration ranges were: 10(3)-10(8) and 10(3)-10(7)MPN/100 mL, respectively. Physical parameters such as electrical conductivity, turbidity and alkalinity ranged 160-1730 μS/cm, 8-916 NTU and 15-698 mg/L, respectively. Effluent total phosphorus (TP), soluble reactive P (SRP), total nitrogen (TN) and ammonium-N (NH4-N) concentrations ranged 1-32, 1651, 213, 176, 63, 14 and 8 times that of stream waters, respectively. Fluorescence characterisation revealed the presence of tryptophan peak in the effluent and downstream waters but not detected upstream from the source. Tank Condition, management and number of users had influenced effluent quality that can pose a direct risk to stream waters as multiple points of pollutants.