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An integrated approach for landslide hazard assessment: A case study of the Middle Dnieper Basin, Ukraine

Ivanik Olena, Fonseca Joana, Shabatura Oleksandr, Khomenko Ruslan, Hadiatska Kateryna, Kravchenko Dmytro

Journal of Water and Land Development

2022

no. 52

81--86

Ukraine is characterised by active natural hazards processes within different structural, tectonic and landscape zones. In Middle Dnieper basin region mass movement processes have great impact on people’s livelihoods and infrastructure. These processes occur on the slopes with different geological structure. The determining causes include lithologic and stratigraphic conditions, hydrogeological regime, structural and textural peculiarities of rocks and the geomorphology of the slopes. Landslide inventory database has been developed based on long-term observations of more than 400 landslides and landslide-prone areas. This paper takes efforts forward by combining different geological and geophysical methods to advance the current understanding of landslide phenomena and contributing towards a better informed assessment of landslide hazard and risk. The developed methodology is implemented in a test sites of Kyiv region, covering an area of 18.3 km2 situated in the Middle Dnieper basin. Electrical Resistivity Tomography, Self-Potential and Infrared Thermography techniques were employed to investigate the lithostratigraphic sequences, the geometry of landslide body and potential mass movement. The results presented here confirm the potential of using an integrated approach that combines different field data to better plan mitigation activities and measures for the effective land management. This study will be useful in increasing the safety aspects of the infrastructures and lives and also for planning of research and developmental activities.

Correlation between Tensile Deformation Behavior and Microstructural Morphology of Nuclear Grade Austenitic Stainless Steel Welded Joints using Infrared Thermography Technique

Rajasekaran R., Lakshminarayanan A. K., Menaka M.

Welding Technology Review

2020

R. 92, nr 1

7--15

Tensile deformation behavior of nuclear grade Austenitic Stainless Steel (SS) and its welded joints fabricated by Gas Tungsten Arc Welding (GTAW) and Activated Flux Gas Tungsten Arc Welding (AGTAW) processes were studied and correlated with relevant microstructural morphologies using Infrared Thermography (IRT) technique. The microstructure of base metal showed a complete austenite phase. GTAW Fusion Zone (FZ) exhibited both primary ferrite and primary austenite mode of solidification. Meantime, AGTAW FZ exhibited only primary austenite mode of solidification. A strain rate of 4.4x10-4 s-1 was used during the tensile test of the base metal and welded joints. The failure locations of the base metal, GTAW and AGTAW samples were noticed at the center of the gauge portion, the base metal side away from Fusion Line (FL) and Heat Affected Zone (HAZ) respectively. The temperature variations of the base metal and weld zones were recorded in the form of thermograms using the IR camera at the different stages of the tensile deformation. During deformation study, peak temperature of 39.2 °C, 38.8 °C and 34 °C were observed at the base metal, GTAW and AGTAW samples respectively. The lesser peak temperature of the AGTAW sample compared to the base metal and GTAW samples indicated that the AGTAW sample undergone lesser deformation. Moreover, tensile deformation behaviours of the base metal and welded joints were correlated with their microstructural morphologies using corresponding temperature curves.

W pracy zbadano zachowanie deformacji podczas rozciągania austenitycznej stali nierdzewnej i jej połączeń spawanych wykonanych metodą GTAW (Gas Tungsten Arc Welding) oraz AGTAW (Activated Flux Gas Tungsten Arc Welding), a następnie skorelowano je z odpowiednimi morfologiami mikrostrukturalnymi za pomocą termografii w podczerwieni (ang. lnfrared Thermography). Mikrostruktura materiału bazowego wykazała całkowitą fazę austenitu. Spoina GTAW wykazywała zarówno ferryt, jak i austenit, podczas gdy spoina AGTAW wykazywała jedynie austenit. Podczas próby rozciągania materiału bazowego i złączy spawanych zastosowano prędkość odkształcania o wartości 4,4x10-4 s-1. Do zerwania poszczególnych próbek doszło odpowiednio na środku próbki materiału bazowego, w linii wtopienia złącza spawanego GTAW i w strefie wpływu ciepła (SWC) złącza spawanego AGTAW. Zmiany temperatury w materiale rodzimym i poszczególnych obszarach złączy spawanych rejestrowano w formie termogramów za pomocą kamery na podczerwień, przy różnych etapach deformacji podczas rozciągania. Podczas badań odkształceń zaobserwowano maksymalne wartości temperatury: 39,2 °C, 38,8 °C i 34 °C odpowiednio w próbkach z materiału bazowego, spawanych GTAW i spawanych AGTAW. Niższa maksymalna temperatura próbki spawanej metodą AGTAW w porównaniu z pozostałymi próbkami wskazała, że uległa ona mniejszemu odkształceniu. Ponadto zachowania deformacji przy rozciąganiu materiału rodzimego i złączy spawanych zostały skorelowane z obrazami ich mikrostruktur przy użyciu odpowiednich krzywych temperatur.