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 a...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.展开更多
The simulation of slope failures,including both failure initiation and development,has been modelled using the material point method（MPM）.Numerical case studies involving various slope angles,heterogeneity and rainf...The simulation of slope failures,including both failure initiation and development,has been modelled using the material point method（MPM）.Numerical case studies involving various slope angles,heterogeneity and rainfall infiltration are presented.It is demonstrated that,by utilising a constitutive model which encompasses,in a simplified manner,both pre-and post-failure behaviour,the material point method is able to simulate commonly observed failure modes.This is a step towards being able to better quantify slope failure consequence and risk.展开更多
In this paper, charge-plasma-based tunnel FET is proposed by employing dual material gate with hetero gate dielectric technique and it is named hetero-dielectric dual material gate doping-less TFET（HD_DMG_DLTFET）. I...In this paper, charge-plasma-based tunnel FET is proposed by employing dual material gate with hetero gate dielectric technique and it is named hetero-dielectric dual material gate doping-less TFET（HD_DMG_DLTFET）. It is compared with conventional doping-less TFET（DLTFET） and dual material gate doping-less TFET（DMG_DLTFET） on the basis of analog and RF performance. The HD_DMG_DLTFET provides better ON state current（I_（ON） =94 μA/ μm）, I_（ON）/I_（OFF）（≈1.36×10^（13））, point（≈3 mV/dec） and average subthreshold slope（AV-SSD40.40 mV/dec）. The proposed device offers low total gate capacitance（C_（gg）/ along with higher drive current. However, with a better transconductance（g_m） and cut-off frequency（f_T）, the HD_DMG_DLTFET can be a good candidate for RF circuitry. The early voltage（V_（EA）/ and output conductance（gd/ are also moderate for the proposed device with comparison to other devices and therefore can be a candidate for analog devices.From all these simulation results and their study, it is observed that HD_DMG_DLTFET has improved analog/RF performance compared to DLTFET and DMG_DLTFET.展开更多
基金the Tertiary Education Fund(TETFUND),Nigeria,for funding this project。
文摘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.
基金supported by the Marie Curie Career Integration Grant(No.333177)the "100 Talents" programme of the Chinese Academy of Science+1 种基金the China Scholarship Councilthe Geo-Engineering Section of Delft University of Technology
文摘The simulation of slope failures,including both failure initiation and development,has been modelled using the material point method（MPM）.Numerical case studies involving various slope angles,heterogeneity and rainfall infiltration are presented.It is demonstrated that,by utilising a constitutive model which encompasses,in a simplified manner,both pre-and post-failure behaviour,the material point method is able to simulate commonly observed failure modes.This is a step towards being able to better quantify slope failure consequence and risk.
文摘In this paper, charge-plasma-based tunnel FET is proposed by employing dual material gate with hetero gate dielectric technique and it is named hetero-dielectric dual material gate doping-less TFET（HD_DMG_DLTFET）. It is compared with conventional doping-less TFET（DLTFET） and dual material gate doping-less TFET（DMG_DLTFET） on the basis of analog and RF performance. The HD_DMG_DLTFET provides better ON state current（I_（ON） =94 μA/ μm）, I_（ON）/I_（OFF）（≈1.36×10^（13））, point（≈3 mV/dec） and average subthreshold slope（AV-SSD40.40 mV/dec）. The proposed device offers low total gate capacitance（C_（gg）/ along with higher drive current. However, with a better transconductance（g_m） and cut-off frequency（f_T）, the HD_DMG_DLTFET can be a good candidate for RF circuitry. The early voltage（V_（EA）/ and output conductance（gd/ are also moderate for the proposed device with comparison to other devices and therefore can be a candidate for analog devices.From all these simulation results and their study, it is observed that HD_DMG_DLTFET has improved analog/RF performance compared to DLTFET and DMG_DLTFET.
