Integrated Simulation Modeling Approach for Investigating Pore Water Pressure Induced Landslides

Soil pore water pressure analysis is crucial for understanding landslide initiation and prediction. However, field-scale transient pore water pressure measurements are complex. This study investigates the integrated application of simulation models (HYDRUS-2D/3D and GeoStudio–Slope/W) to analyze pore water pressure-induced landslides. The proposed methodology is illustrated and validated using a case study (landslide in India, 2018). Model simulated pore water pressure was correlated with the stability of hillslope, and simulation results were found to be co-aligned with the actual landslide that occurred in 2018. Simulations were carried out for natural and modified hill slope geometry in the study area. The volume of water in the hill slope, temporal and spatial evolution of pore water pressure, and factor of safety were analysed. Results indicated higher stability in natural hillslope (factor of safety of 1.243) compared to modified hill slope (factor of safety of 0.946) despite a higher pore water pressure in the natural hillslope. The study demonstrates the integrated applicability of the physics-based models in analyzing the stability of hill slopes under varying pore water pressure and hill slope geometry and its accuracy in predicting future landslides.

Assessment of Erosion Characteristics in Purple and Yellow Soils Using Simulated Rainfall Experiments

Soil erosion of sloped lands is one of the important sources of substantive sediments in watersheds. In order to investigate erosion characteristics of sloped lands during rainfall events in the Three Gorges Reservoir Area, erosion processes of purple and yellow soils under different slope gradients and rainfall intensities were studied by using a rainfall simulator. The results showed that the sediment concentration in runoff was closely correlated with rainfall intensity. The sediment concentration in runoff gradually rose to a peak with time, and then gradually declined and approach a steady rate during simulation rainfall events. The particle size distribution of surface soils before the rainfall was different from that after the rainfall. Soil erosion mainly resulted in the loss of fine particles of surface soil through runoff, and the fine particles of soil were enriched in sediments. Soil erosion rates were gradually increased with the slope gradient when the slope gradient was less than 10°, and significantly increased when the slope gradient was more than 10°. The slope factor of yellow soil could be fitted well to that calculated by the formula of Universal Soil Loss Equation (USLE). The trend of the slope factor of purple soil was similar to that of the slope factor that was derived from USLE. Therefore, the effect of slope gradients on soil erosion need to be further researched when USLE was applied to predict erosion in purple soil area.

Attainment of low subthreshold slope in planar inversion-channel InGaAs MOSFET with in-situ deposited Al2O3/Y2O3 as a gate dielectric

We have demonstrated a record low 85 mV/dec subthreshold slope (SS) at 300 K among the planar inversion-channel InGaAs metal-oxide-semiconductor field-effect transistors (MOSFETs). Our MOSFETs using in-situ deposited Al2O3/Y2O3 as a gate dielectric were fabricated with a self-aligned inversion-channel metal-gate-first process. The temperature-dependent transfer characteristics showed a linear reduction of SS versus temperature, with attainment of an SS of 22 mV/dec at 77 K; the value is comparable to that of the state-of-the-art InGaAs FinFET. The slope factor of SS with temperature (m) is 1.33, which is lower than those reported in the planar InGaAs MOSFETs.

The potential for land erosion due to primary tin mining in Bangka Island

In the context of primary tin mining by PT. Timah on the Bangka Island, an analysis of environmental impacts is needed concerning various related aspects. One of the potential impacts that need to be considered is erosion due to open land for mining activities. Rain and mining water triggers the process of erosion on open land with particular soil and topographic characteristics. This paper presents an analysis of the potential for erosion due to primary tin mining at five mining locations in Bangka Island. The soil erosion rate can be analyzed using the Universal Soil Loss Equation (USLE) and GIS. The environmental data used to predict the erosion rate include soil type, soil texture and structure, land cover, rainfall, slope, and soil management techniques. In this study, rainfall erosivity is taking into account based on average monthly rainfall from 2010-2019. The results showed that the erosion rates at the primary mining sites are relatively low, ranging from 4.72 to 683.47 tons/ha/year. The results showed that the erosion rate is more influenced by the topography (slope factor). Besides, the considerable land-use change will also contribute significantly to the amount of soil erosion.

Critical Re-evaluation of the Slope Factor of the Operational Model of Agonism Short Title: Slope Factor of the Operational Model of Agonism

Although being a relative term, agonist efficacy is a cornerstone in the proper assessment of agonist selectivity and signalling bias. The operational model of agonism (OMA) has become successful in the determination of agonist efficacies and ranking them. In 1985, Black et al. introduced the slope factor to the OMA to make it more flexible and allow for fitting steep as well as flat concentration-response curves. Functional analysis of OMA demonstrates that the slope factor implemented by Black et al. affects relationships among parameters of the OMA. Fitting of the OMA with Black et al. slope factor to concentration-response curves of experimental as well as theoretical data (homotropic allosteric modulation, substrate inhibition and non-competitive auto-inhibition) resulted in wrong estimates of operational efficacy and affinity. In contrast, fitting of the OMA modified by the Hill coefficient to the same data resulted in correct estimates of operational efficacy and affinity. Therefore OMA modified by the Hill coefficient should be preferred over Black et al. equation for ranking of agonism and subsequent analysis, like quantification of signalling bias, when concentration response curves differ in the slope factor.

EVALUATION METHOD FOR ALLOWABLE SHORT-TERM FLEXURAL STRENGTH AND YIELD STRENGTH OF CONCRETE-FILLED STEEL TUBULAR BEAM-COLUMNS

According to the Recommendations for Design and Construction of Concrete Filled Steel Tubular Structures from Architectural Institute of Japan, the allowable short-term flexural strength (ASFS) can be used as the yield strength for the restoring force characteristics model of concrete-filled steel tube (CFST) members. Therefore, it is necessary to examine whether the ASFS can be appropriate as an alternative for the yield strength. Furthermore, as the ASFS is typically calculated using the superposition method, the value of the deformation at the superposed strength cannot be evaluated. To address these issues, in this study, numerical analysis was conducted on the moment-curvature relation of CFST column sections using the finite fiber method. The characteristics of the point of ASFS and evaluation method for flexural yield strength in a broad sense were examined using the slope factor and strength satisfaction factor methods. The corresponding slope factor is larger than the value (1/3) that is generally used for the yield strength definition. Therefore, using the ASFS is as the yield strength of the CFST section is reasonable. Additionally, the formula for the curvature at the ASFS was also proposed.

PENGARUH TOPOGRAFI LAHAN TERHADAP PRODUKTIVITAS KELAPA SAWIT (Elaeis guineensis Jacq.) DI PT. DHARMA INTISAWIT NUGRAHA MUARA WAHAU KABUPATEN KUTAI TIMUR

Oil palm is one of the potential commodities whose cultivation trend began in 2003 in EastKalimantan which has the characteristics of hilly land. Oil palm itself is preferable to grow at analtitude of 400 m asl with a slope of up to 23% or at 12°.Therefore, this research is motivated todetermine the yield of oil palm plantations in certain land slope classifications. The study wasconducted on 2 afdeling which have different land classifications with an area of ± 14,000 ha.Thenfor comparison, it was taken through production data in 2019 with 2 treatments and 12 replications,which were processed using Analysis Of Variance (ANOVA) Two Way Anova. Primary data wereobtained through field observations, as well as soil sampling, which were analyzed directly for soilphysical properties and laboratory for chemical properties including pH H2O, Nitrogen (N),Phosphorus (P), Potassium (K) and Magnesium (Mg.). The results of the research on the effect ofslope on oil palm production by various methods indicate that the land slope factor does not have asignificant effect on oil palm productivity.

Factors Affecting Slope Instability of the Nhan Co Alumina Red Mud Basin and Economical, Environmentally Friendly Soil Stabilization

Since 2017, there have been recurring landslides in the red mud basins of the Nhan Co alumina factory, Dak Nong Province, Vietnam, during the rainy seasons. Changes in physical and mechanical soil parameters due to rain water infiltration and the formation of tension cracks have been considered as the main causes of slope instability. The soil cohesion and angle of internal friction decreased nearly thrice and twice, respectively, as the soil became saturated. An economical and environmentally friendly reinforcement using bamboo stem piles in combination with slope regrading is suitable for the site conditions. With a light slope regrading, a bamboo stem pile spacing of 5.3 m ensures that the slope factor of safety (FS) is 1.30, which satisfies the requirements specified by the national technical regulations. The results are helpful and serve as practical fundamentals for a comprehensive control of slope stability of the red mud basins in the Nhan Co alumina factory to avoid possible catastrophic destruction of the local ecology by the spreading of an extremely high pH fluid and mud from the red mud basins due to the landslides into the red mud basins.

Study on the influence of slope height and angle on the factor of safety and shape of failure of slopes based on strength reduction method of analysis

Background Decreasing slope angle and slope height increases the slope factor of safety and can change the shape of likely slope failure. The increase in the factor of safety is at different rates, which can depend on soil type and slope geometry. Understanding the relationship between the slope height and angle decrease with the increase in factor of safety is vital to implement an efficient method of increasing factor of safety for slope stability problems. In addition, the shape of slope failure has to be observed thoroughly, not to increase the sliding mass of soil for a likely slope failure, even though the factor of safety has increased. Results Three homogeneous slopes of different soil characteristics were analyzed several times by changing the slope height and angle to determine the factor of safety. The shape of failure was also observed and recorded for each slope height and angle decrease. The analysis results indicated that decreasing slope angle increases the factor of safety nearly linearly while a decrease in height increases the factor of safety at a parabolic rate. Slope height decrease increased the factor of safety at a higher rate for the clay soil while slope angle decrease increased factor of safety at a higher rate for sandy soil compared to the other types of soils considered. The toe slide was observed in clayey and sandy clay soils at higher slopes while the base slide was observed at slopes whose height is less than 2 m. The slope slide was dominant on sandy soil at different slope heights and slope angles. Conclusions While the factor of safety of slopes had increased with slope height and angle decrease, the rate of increases and thus the efficiencies are different which depended on the type of soil and geometry of slope. The shape of failure also changed which might increase the sliding mass of soil. This can be risky if slope failure occurs due to unforeseen events. Using the slope height and angle decrease methods for slope stabilization should be thoroughly investigated to choose the most efficient method and also should be checked not to increase the sliding mass of soil for a possible slope failure.