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RISS 인기검색어
- 검색키워드
- 저자 : D. Vasu (검색결과 3 건)
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Coupled model for simulation of landslides and debris flows at local scale
Park, D. W.,Lee, S. R.,Vasu, N. N.,Kang, S. H.,Park, J. Y. Springer-Verlag 2016 Natural hazards Vol.81 No.3
<P>This research connects different but sequential processes of slope failure: landslide occurrence, debris-flow initiation from landslides, and debris-flow propagation to lowlands. The coupled model presented in this study consists of a deterministic landslide susceptibility model that estimates the landslide source and local geomorphological mobilization criteria for selecting debris-flow initiation points, and an empirical debris-flow model that simulates the transport and propagation of failed materials from the identified source areas. The debris flow initiation in the spreading analysis was estimated from the landslide source by landslide analysis. Then, its inspection using the mobilization criteria was used to determine if the landslide transformed into a debris flow. While the geomorphological criteria were calibrated using data obtained from Gyeong-gi Province, the validation of the coupled approach was done at Mt. Woomyeon. In comparison with a landslide inventory map, the model simulations resulted in reasonable estimates of all the mountain hazards caused by slope failures as a sequential process on a local scale. The coupled analysis proposed in this study affirms that it is important to manage them together because of the correlation between landslides and debris flows. Thus, if it is parameterized and calibrated for local conditions the suggested model, linking landslides and debris flows with the mobilization analysis, provides a powerful tool for decision makers in territorial planning and disaster preparedness.</P>
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Nedumpallile Vasu, N.,Lee, S.R.,Pradhan, A.M.S.,Kim, Y.T.,Kang, S.H.,Lee, D.H. Elsevier Pub. Co 2016 Engineering geology Vol.215 No.-
An ever-increasing trend of extreme rainfall events in South Korea due to climate change is causing shallow landslides and shallow landslide induced debris flows in the mountains that cover 70% of the total land area of the nation. These catastrophic, gravity-driven processes cost the government several billion won in losses, and attendant fatalities, every year. The most common type of landslide observed is the shallow landslide occurring at 1-3m depth, which may mobilize into a catastrophic debris flow. A landslide early warning system encompassing different scale-based stages is used to predict potential areas for both the landslide types. Current study focusing on the first stage landslide hazard assessment at regional or medium scale requires the development of spatially evolving landslide hazard maps for both types of landslides based on the real-time rainfall. However, lack of complete landslide inventory data motivates the development of temporal and spatial models as independent components of the landslide hazard. Most of the existing temporal assessment schemes traditionally rooted in recurrence-based concepts does not consider soil factors and are not suitable to be incorporated in to the landslide early warning system since real-time rainfall cannot be considered. This motivated the development of a new probabilistic temporal model termed the extreme rainfall-induced landslide index. The probabilistic index was developed in Gangwon Province through a logistic regression using four factors; namely, continuous rainfall, 20-days antecedent rainfall, saturated hydraulic conductivity, and storage capacity. The developed model exhibited high area under the curve (AUC) values of 82% and 91% obtained for the training and validation curves, exhibiting good performance of the statistical index. Also, a high performance susceptibility model (training and validation AUC values of 96% and 94%, respectively) was developed using a logistic regression analysis, for Deokjeok-ri Creek, located in Gangwon province. Assuming the independence of the hazard components, a dynamic hazard index (DHI) was established through a joint probability of both the well validated models. The DHI was used to study the evolution of landslide hazard for the July 2006 extreme rainfall-induced landslide events in Deokjeok-ri Creek.
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K. Navaneetha Pandiyaraj,D. Vasu,A. Raji,Rouba Ghobeira,Parinaz Saadat Esbah Tabaei,Nathalie De Geyter,Rino Morent,M.C. Ramkumar,M. Pichumani,R.R. Deshmukh 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-
The current study investigates the combinatorial effect of the photocatalytic performance of plasma pretreatedTi-Cu-Zn doped graphene oxide (TCZ-GO) nanoparticles (NPs) and advanced oxidation processesof a non-thermal atmospheric pressure plasma on the degradation of reactive orange-122 (RO-122) dyecompounds. Firstly, in order to enhance the photocatalytic performance of the synthesized compositeNPs, they were subjected to glow discharge plasma treatments operating in different gases (Ar, air, O2and N2). Their surface morphology, chemical composition and band gap were examined by means ofscanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV–Vis spectrophotometryrespectively. XPS results revealed that plasma-treated NPs exhibited a higher content of oxygenvacancies and a variation in their oxidation states (Ti4+?Ti3+, Cu+?Cu2+). These plasma-induced surfacechemical changes hindered the recombination of photo-generated electron-hole pairs which led to a dropin the bandgap of the NPs with N2 plasma-treated NPs acquiring the lowest bandgap. Lastly, the articleexamined the actual decomposition of RO-122 dye in wastewater by an Ar plasma treatment alone orcombined with the plasma-treated TCZ-GO NPs via spectrophotometric analyses, electrical conductivity,pH and total organic carbon (TOC) removal measurements. Moreover, the reactive species produced duringthe combined plasma/photocatalysis induced degradation were detected in situ by optical emissionspectroscopy. Results revealed that the processes carried out by combining N2 plasma-treated TCZ-GONPs and Ar plasma exhibited the highest degradation efficiency (85 %) due to the generation of moreOH and H2O2. Overall, it can be concluded that plasma-aided treatment processes used synergisticallyas indirect surface functionalization of TCZ-GO NPs and direct plasma treatment of wastewater are extremelyefficient in the degradation of toxic compounds and can be extrapolated to various environmentalapplications.
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