Geotechnical and GIS-based environmental factors and vulnerability studies of the Okemesi landslide,Nigeria

Landslide is a geological hazard typically associated with extreme events such as earthquakes,heavy rainfall,volcanic eruptions,changes in groundwater level,etc.This study was carried out in Okemesi-Ekiti(also known as Okemesi),Southwest Nigeria,with the purpose of using remote sensing and GIS technologies to analyze the environmental factors(grain size,direct shear strength resistance,rainfall data,wet density,surface,and slope)resulting in the occurrence of the Okemesi landslide.The study also aimed to conduct a vulnerability analysis in the study area to identify regions with a probability of landslide occurrence.The grain size analysis of the soil in the Okemesi landslide area showed that slope materials comprised 17.14%gravel,59.31%sand,and 19.48%fines,thus the soil type could be classified as poorly graded gravely sand with a high possibility of landslide occurrence.The geomorphic characteristics of the study area was characterized by slopes ranging from 0.00°to 49.00°,while most slopes in the area were less than 8.00°.The slope aspect direction was mainly in south(157.51°–202.50°),southwest(202.51°–247.50°),west(247.51°–292.50°),and north(0.00°–22.50°and 337.51°–360.00°).The highlands were primarily bounded by the slope directions of north(0.00°–22.50°and 337.51°–360.00°),northeast(22.51°–67.50°),east(67.51°–112.51°),and southeast(112.51°–157.50°),which indicated the potential direction of mass movement.The study area can be divided into three vulnerability zones:high,medium,and low,with the area percentages of 9.00%,61.80%,and 29.20%,respectively.The analysis suggested that the Okemesi landslide was likely triggered by rainfall,which might have weakened the physical structure of slope materials.Understanding the causes and impacts of landslides is crucial for policymakers to implement measures to mitigate landslide hazards,protect infrastructure,and prevent the loss of life in the landslide-prone regions.

Prediction of vulnerable zones based on residual stress and microstructure in CMT welded aluminum alloy joint

Numerical simulation and experimental results were employed for the identification of the most vulnerable zones in three-pass cold-metal-transferring （CMT） welded joint. The residual stress distribution in the joint was predicted by finite element （FE） method, while the structural morphology of distinctive zones was obtained through metallographic experiments. The highest principal stress made the symmetric face of the joint most sensitive to tensile cracks under service conditions. Whereas, the boundaries between the weld seam and the base plates were sensitive to cracks because the equivalent von Mises stress was the highest when the first interpass cooling was finished. The third weld pass and the inter-pass remelted zones exhibited the modest mechanical performances as a result of the coarse grain and coarse grain boundary, respectively. The most vulnerable zones were regarded to be the crossed parts between the zones identified by numerical and experimental methods.

Agriculture and Water Sources Protection Zones in the Czech Republic

The area of interest is located in the South Moravia Region at the confluence of the Jihlava, Oslava and Rokytn^i rivers. Ivan^ice spring area comprises a series of hydrologic boreholes, it is the main water source for water supply of Ivan^ice and Rosice towns and provides water for 30,000 inhabitants. The risk analysis was created on the basis of water quality monitoring, hydrogeological assessment and terrain exploration and a revision of protection zones was proposed. The spring area is situated in nitrate vulnerable zones and recently nitrate concentrations have been decreasing. Water quality evaluation results： high concentration of manganese and iron, sometimes higher concentration of ammonium and COD. This area is intensively used for agriculture and it is necessary to make a compromise solution during protection zones proposal, The regime in protection zones can not affect manganese and iron concentration （their origin is in the natural geological environment）. Therefore, water treatment plant is in operation and its modernization is proposed. Furthermore, the paper deals with spring area intensification construction of a new hydrologic borehole, and managed and unmanaged infiltration of surface water. The proposal of protection zones revision consists of reduction to a 2nd level protection zone.