Slope Of Distribution Research Articles

Frequency distribution of different joint slopes containing ceramic soil under seismic wave action

The dynamic response characteristics of high and steep slopes under the action of earthquakes and blasting was focused on, especially the frequency distribution and propagation laws, which are crucial for slope stability assessment. Using stress wave theory as the theoretical basis and advanced FLAC3D numerical simulation technology, we systematically analyze the frequency response of slope under different joint conditions under seismic waves. The nonlinear characteristics of reflected P-wave coefficient and the significant sensitivity of joint to incident wave frequency are revealed when the Angle of incident P-wave changes. The results show that with the increase of the incidence Angle of the incident P-wave, the reflection coefficient of the reflected P-wave decreases slowly at first and then increases sharply to 1.0. The reflection coefficient of the wave at the joint is more sensitive to the frequency of the incident wave. In a biplanar rock mass, multiple reflections of waves between structural planes produce transmitted waves with different time differences.

Soil Properties Classification in Sustainable Agriculture Using Genetic Algorithm-Optimized and Deep Neural Networks

Optimization of land management and agricultural practices require precise classification of soil properties. This study presents a method to fine-tune deep neural network (DNN) hyperparameters for multiclass classification of soil properties using genetic algorithms (GAs) with knowledge-based generation of hyperparameters. The focus is on classifying soil attributes, including nutrient availability (0.78 ± 0.11), nutrient retention capacity (0.86 ± 0.05), rooting conditions (0.85 ± 0.07), oxygen availability to roots (0.84 ± 0.05), excess salts (0.96 ± 0.02), toxicity (0.96 ± 0.01), and soil workability (0.84 ± 0.09), with these accuracies representing the results from classification with variations from cross-validation. A dataset from the USA, which includes land-use distribution, aspect distribution, slope distribution, and climate data for each plot, is utilized. A GA is applied to explore a wide range of hyperparameters, such as the number of layers, neurons per layer, activation functions, optimizers, learning rates, and loss functions. Additionally, ensemble methods such as random forest and gradient boosting machines were employed, demonstrating comparable accuracy to the DNN approach. This research contributes to the advancement of precision agriculture by providing a robust machine learning (ML) framework for accurate soil property classification. By enabling more informed and efficient land management decisions, it promotes sustainable agricultural practices that optimize resource use and enhance soil health for long-term ecological balance.

Investigation on the Instability Mechanism of Expansive Soil Slope With Weak Interlayer Based on Strain Softening

ABSTRACTExpansive soils are widespread in the world and coincide with areas of high human activity. The main cause of deep instability of expansive soil slopes is due to their softening caused by excavation and seepage. By developing a comprehensive numerical model based on the theory of unsaturated soil, this study examines the characteristics of stress and displacement distribution of expansive soil slopes through hydraulic‐mechanical coupled numerical simulation. This study analyzes the evolution patterns of slopes with excavation unloading and seepage of water storage to reveal the mechanisms of deep‐seated instability of expansive soil slopes. The findings demonstrate that: The instability of expansive soil slopes begins at the foot of the slope and propagates along the interlayer, affecting the entire slope. Excavation leads to the softening of the expansive soil interlayer and the transfer of shear stress. During water storage, the weakening of the soil strength results in slope instability along the weak interlayer slip. Softening of the expansive soil interlayer facilitates the redistribution of shear forces in the slope and alters the distribution law of the plastic zone in the deep layer. Overly slowing down the slope leads to significant excavation unloading, which is detrimental to the slope's stability.

Inventorization of Spring Water Resources in Mid Hills of Himachal Pradesh, India

The study on spring inventory was conducted in the mid hills of Himachal Pradesh, India where 43 springs were inventoried in the Beas catchment area. Hydrogeological characteristics, such as geology, slope, aspect, elevation, rock and soil distribution, landuse, geomorphology, and spring discharge were utilized to access the condition of springs in the study area. The study showed that 40.12% of the springs have seen a drop in water flow and compared to the previous times, the water flow has increased in 4.85% of the springs. A total of 56% of spring is located in the forest, 32% in Agriculture land, 3% in grassland, 6% in Shrubland, 2% in built up area, 1% in barren land. 65% are depression springs, 28% are fracture springs, and 7% are contact springs. 2.32% of the spring sources had discharge rate <0.05 Lmin-1. 79.06% of the springs have average discharge rate of 1-10 Lmin-1. Rest of the 11.60% of the springs have discharge rate ranged from 10-25 Lmin-1. Most of the springs are fed by annual precipitation and those located near the Beas valley are supported by river water course.

Improved calibration method based on phase-slope description in phase-shift deflectometry

Phase-shift deflectometry is a widely used high-precision gradient measurement method for assessing the topography of specular objects. The calibration of phase-shift deflectometry measurement systems involves establishing the phase-slope mapping relationship. This paper analyzes the causes of phase variations at different calibration points in existing phase-slope analysis models. Based on the fact that changes in height simultaneously produce phase variations in two perpendicular directions, a decoupling method is proposed to address the phase ambiguity problem to some extent. Through simulation, the variation in height phase and slope distribution were quantitatively analyzed for a unidirectional inclined plane to validate the proposed algorithm. Additionally, measurement experiments were performed on a unidirectional inclined plane with an inclination angle of −2.584° and a concave mirror with a curvature radius of 779.87 mm. Based on the findings, the decoupling method reduced the relative root-mean-square error of the gradient measurement for the inclined plane in the inclined direction by 2.206% and improved the error range of the curvature radius for the concave mirror from [0.55%, 4.1%] to [0.22%, 3.86%]. By comparing with the existed method, the decoupling method showed a certain advantage in practicality.

Human activities are intensifying the spatial variation of landslides in the Yellow River Basin

Human activities are a triggering factor for landslides in the Yellow River Basin (YRB, China). However, the extent to which the spatial distribution of landslides is affected by human activities is unclear. We constructed a human activity intensity index (HAII) based on nighttime light data and land cover data. Regression and dominance analyses were used to compare the effects of the HAII, precipitation, distance to river, distance to fault, topographic relief and slope on the landslides spatial density (LSD). The results showed that in the YRB, the HAII, as a dominance influencing factor, had a significant positive influence on the LSD. Moreover, regional differences in the human disturbance of nature intensify the spatial variation of LSD. To quantify the intensity of human disturbance to nature, a human-nature conflict index (HNCI) is constructed by quantifying the difference between the slope distributions of artificial and natural landscapes. The results show that in the middle section of the YRB, humans are developing more steep mountainous areas, leading to more dense landslides. This study provides a reference for landslide risk management and land use planning in the YRB.

Tectonic, Topographic, Geologic, and Hydroclimatic Influence on Crack Formation During the 2021 Haiti Earthquake

AbstractThe 14 August 2021 Haiti earthquake mainly portrayed reverse motion to the east near L’Asile town and left‐lateral strike‐slip motion to the west near Camp‐Perrin town. To map the rupture and infer its segmentation, we conducted the first post‐seismic field reconnaissance along the left‐lateral strike‐slip Enriquillo fault from L’Asile to Macaya mountain. We identified 98 linear, minor cracks that are not representative of primary fault surface rupture. Analyzing the topographic slope distribution, we detected that the cracks were often located in areas that are prone to topographic instability. About 60% of the cracks are located in Quaternary alluvium and Middle‐Miocene continental marls, indicating a preference for soft sediments. The rivers also have an impact, as crack lengths and openings negatively correlate with their distance to neighboring rivers. In addition, the earthquake occurred in a rainy region with up to 2,479.34 mm of rainfall in 2021, increasing soil instability. Above all, we found a contrast and asymmetry between the eastern and the western parts of the rupture. By dividing the 60‐km long rupture into two equal parts, we observed 57 cracks to the west against 41 to the east. The longest and the widest cracks are to the west. Analyzing their orientation, the cracks mainly oriented as left‐lateral strike‐slip faults to the west and mainly thrusts to the east. This configuration appears to be influenced by the slip pattern of the 2021 Haiti earthquake and consistent with the regional stress field.

Investigation of Ripple Formation on Surface of Silicon by Low-Energy Gallium Ion Bombardment.

Regular wave patterns were created by a 2 kV gallium ion on Si(111) monocrystals at incidence angles between 60° and 80° with respect to the surface normal. The characteristic wavelength and surface roughness of the structured surfaces were determined to be between 35-75 nm and 0.5-2.5 nm. The local slope distribution of the created periodic structures was also studied. These topography results were compared with the predictions of the Bradley-Harper model. The amorphised surface layers were investigated by a spectroscopic ellipsometer. According to the results, the amorphised thicknesses were changed in the range of 8 nm to 4 nm as a function of ion incidence angles. The reflectance of the structured surfaces was simulated using ellipsometric results and measured with a reflectometer. Based on the spectra, a controlled modification of reflectance within 45% and 50% can be achieved on Si(111) at 460 nm wavelength. According to the measured results, the characteristic sizes (periodicity and amplitude) and optical property of silicon can be fine-tuned by low-energy focused ion irradiation at the given interval of incidence angles.

Landing site choice for Luna-27 mission in the Moon South Polar Region

In this study, we examine the Russian automatic lunar missions “Luna-25,” “Luna-26,” and the scientific objectives and landing site of the “Luna-27″ spacecraft. The landing of “Luna-27″ is planned directly in the South Polar region, which, due to ballistic and engineering requirements, is confined to a sector extending from 51°E to 1°W in longitude and from 83°S to 79°S in latitude. This area is characterized by complex terrain, and to identify suitable landing territories, a suitability map has been created that takes into account the distribution of slopes, the degree of illumination, and visibility of Earth. A total of five sites measuring 30 × 15 km (landing ellipse) within the considered region meet such scientific and technical requirements as slope distributions of less than 7–10°, sunlight illumination of more than 35 %, and Earth visibility of more than 50 %. All landing sites are ranked by priority from 1 to 5 depending on the content of water equivalent of hydrogen (WEH) in the lunar soil. Site №1, by its characteristics, is considered the best and may be chosen as the primary landing site, while sites №2 and №3 could serve as backups. It is demonstrated that with increased landing precision, with a deviation probability from the given point up to 0.5 km, the number of suitable landing sites satisfying primarily scientific rather than engineering-technical safety criteria, which are also inherently met, significantly increases.

Multiscale slope analysis and functional correlation with gloss reflectance from photographic papers

A novel multiscale 3D topographic characterization for slope is introduced. Slope is considered as a crucial parameter linking area-scale and 3D curvature analyses. Relationships between surface topography and gloss reflectance in photographic papers are used for an example application. Directional angles, characterizing slopes, are calculated two ways: normals to triangular facets (method 1), and eigenvectors of a covariance matrix based on nine points (method 2). Slope is the steepness of surface inclinations associated with the orientation of local surface features (facets). The impact of slope on gloss reflectance supports the use of pertinent geometric characterizations, i.e., alignment of geometric characterizations with the physical nature of the topographic interaction phenomena. Topographies of 24 photographic papers, were measured with a laser scanning confocal microscope and their gloss reflectance was measured with a micro-TRI-gloss gloss meter. Analyses of slope distributions with bivariate dispersion measures of directional angles and their trigonometric functions revealed strong correlations (R2 > 0.6) between slope distributions and gloss. Bivariate median deviation of secant or tangent of directional angles, demonstrated consistently high correlations across scales, magnifications, and filtrations. This study supports pertinent and useful characterizations grounded in the physics of topographic interaction phenomena to provide insights into relationships between surface topography, e.g., slope and gloss reflectance in photographic papers. This nuanced understanding has potential applications for other applications as well.

Impacts of future climate and land use/land cover change on urban runoff using fine-scale hydrologic modeling

Future changes in land use/land cover (LULC) and climate (CC) affect watershed hydrology. Despite past research on estimating such changes, studies on the impacts of both these nonstationary stressors on urban watersheds have been limited. Urban watersheds have several important details such as hydraulic infrastructure that call for fine-scale models to predict the impacts of LULC and CC on watershed hydrology. In this paper, a fine-scale hydrologic model—Personal Computer Storm Water Management Model (PCSWMM)—was applied to predict the individual and joint impacts of LULC changes and CC on surface runoff attributes (peak and volume) in 3800 urban subwatersheds in Midwest Florida. The subwatersheds a range of characteristics in terms of drainage area, surface imperviousness, ground slope and LULC distribution. The PCSWMM also represented several hydraulic structures (e.g., ponds and pipes) across the subwatersheds. We analyzed changes in the runoff attributes to determine which stressor is most responsible for the changes and what subwatersheds are mostly sensitive to such changes. Six 24-h design rainfall events (5- to 200-year recurrence intervals) were studied under historical (2010) and future (year 2070) climate and LULC. We evaluated the response of the subwatersheds in terms of runoff peak and volume to the design rainfall events using the PCSWMM. The results indicated that, overall, CC has a greater impact on the runoff attributes than LULC change. We also found that LULC and climate induced changes in runoff are generally more pronounced in greater recurrence intervals and subwatersheds with smaller drainage areas and milder slopes. However, no relationship was found between the changes in runoff and original subwatershed imperviousness; this can be due to the small increase in urban land cover projected for the study area. This research helps urban planners and floodplain managers identify the required strategies to protect urban watersheds against future LULC change and CC.

Investigation of the shape-changing property of X-ray computed tomography in the evaluation of pores

Porosity in additive manufacturing is one of the main quality characteristics for components. In processes such as laser-based powder bed fusion of metals (LPBF-M), correlations can be observed between the process parameters used, such as laser power, hatch distance or layer thickness, and the pore shape produced. Therefor the surface depending criterion sphericity is a crucial parameter for the classification of pores. In addition to methods like micrographs or Archimedes' density determination, industrial X-ray computed tomography (CT) is a key measurement method for the spatial but also shape-dependent assessment of pores in components. However, due to the lack of standards, no measurement uncertainty for shape, position, and volume can be given for CT measurements. With the help of CT simulations and models for detector and X-ray source to real CT system, investigations can be made on the dependencies and influence on the detectability of pores. This study shows that the CT measurements as well as the analysis have an influence on the detectable volume and surface of pores. By modelling pore models with cosine periodic spatial frequencies (peaks), the spatial influence of CT on detectability can be investigated and assessed as a form of slope distribution. The simulation-based measurement uncertainty information can be used to improve the separation of pore shape classifications and thus contribute to the development of additive manufacturing.

Stability and Distribution of Rock Slope under Asymmetric Excavation

Stability and Distribution of Rock Slope under Asymmetric Excavation

The elevated low-relief landscapes of the Eastern Alps

The morphology of the Eastern European Alps is characterized by a bimodal slope distribution with relatively flat surface areas located at both high and low elevations. While low-slope regions in valley floors are easily explained by base-level erosion or sediment fill, low-slope surfaces at summit levels are unusual and have both been interpreted to (a) have formed by glacial erosion or (b) reflect remnants of old base levels that survived uplift and subsequent erosion. In order to contribute to this debate, we present a map of these surfaces on the scale of the Eastern Alps (mapped at roughly 1:300,000 scale). Importantly, our mapping covers both areas glaciated in the Pleistocene and areas that have remained unglaciated.Mapping results show that elevated low relief surfaces occur at roughly equal proportions in formerly glaciated and unglaciated regions, thus giving strong support to the notion that they are relicts of paleosurfaces formed at base level. As karst caves often form near the phreatic-vadose transition also at base level, we support our interpretation with a statistic analysis of passage lengths of some 13,000 karst caves in the region. Hypsometric analysis shows that the distribution of low-relief surfaces differs between formerly ice-covered and ice-free regions. We explain this by glacial overprinting of the surfaces during the Pleistocene. Based on the hypsometric analysis a correlation of the low-relief surface and caves across the Eastern Alps remains unclear, most likely because uplift varies across the region. However, plotting the elevation of the paleosurfaces relative to an arbitrary base level of the nearest 300 km2 catchment provides distinct peaks in hypsometric analysis suggesting a somewhat clearer correlation of levels between different regions.Because many of these surfaces are known to have formed at base level in the Pliocene, we therefore suggest that Pliocene surface-uplift in much of the Eastern Alps is of long wavelength. Topographic differences between major valleys and basins surrounding the Alps were created due to erodibility contrasts between Miocene sediments and basement. Tectonic dissection of the Eastern Alps causing variable uplift rates of different blocks appears to have been minor in the last 5 my of the uplift history.

Clustering index analysis on EMG-Torque relation-based representation of complex neuromuscular changes after spinal cord injury

Spinal cord injury (SCI) resulting in complex neuromuscular pathology is not sufficiently well understood. To better quantify neuromuscular changes after SCI, this study uses a clustering index (CI) method for surface electromyography (sEMG) clustering representation to investigate the relation between sEMG and torque in SCI survivors. The sEMG signals were recorded from 13 subjects with SCI and 13 gender-age matched able-bodied subjects during isometric contraction of the biceps brachii muscle at different torque levels using a linear electrode array. Two torque representations, maximum voluntary contraction (MVC%) and absolute torque, were used. CI values were calculated for sEMG. Regression analyses were performed on CI values and torque levels of elbow flexion, revealing a strong linear relationship. The slopes of regressions between SCI survivors and control subjects were compared. The findings indicated that the range of distribution of CI values and slopes was greater in subjects with SCI than in control subjects (p < 0.05). The increase or decrease in slope was also observed at the individual level. This suggests that the CI and its sEMG clustering-torque relation may serve as valuable quantitative indicators for determining neuromuscular lesions after SCI, contributing to the development of effective rehabilitation strategies for improving motor performance.

A soil mechanics model to determine the onset of wind erosion

Determining the friction threshold velocity (FTV) of wind-induced erosion is crucial to understanding and predicting the morphodynamics and management of foreshores and dunes. However, the FTV is influenced by multiple factors, including particle size, mineralogy, surface roughness, and moisture content. Although existing models account for these parameters, they suffer from limited precision, are not generalized and developed for specific sediment types, and rely on expensive and time-consuming testing procedures. Furthermore, no predictive equations for FTV currently consider the combined effects of bed inclination and moisture common to coastal dunes. This study presents a comprehensive closed-form model for predicting the FTV in the onset of wind erosion for different types of sands. The model considers various geometric and material properties, including cohesion, moisture, soil packing, slope, and grain size distribution. A soil water retention curve (SWRC) is incorporated into the formulation to establish a relationship between water content and sediment shear strength. This simple SWRC approach enables simplified calculations of the onset of wind erosion under various conditions, requiring only a few inexpensive inputs. Extensive parametric wind tunnel experiments were conducted to measure the FTV in combinations of bed slope, sand particle size, moisture, and density. The findings indicate that the combined influence of slope and moisture increases the FTV. Furthermore, compared to the FTV for dry sediments on a horizontal bed, the amplification factor exhibits a nonlinear combination of the effects of inclination and moisture. The proposed FTV predictive model demonstrates adequate agreement with published results when applied to scenarios such as dry sand on a horizontal surface, dry sand on an inclined bed, and moist sand on a horizontal surface.

Spatial and Temporal Dynamics of Ecological Parameters in Various Land Use Types in China during the First 20 Years of the 21st Century

Ecological quality in China has experienced significant improvements due to the interplay of climate change and human activities. Nevertheless, previous studies exploring the trend of ecological parameters have always overlooked the effects of land use types. Therefore, in this study, we explored the spatiotemporal variation in ecological parameters in various land use types and discussed the relationship between ecological parameters and climatic factors in China during the first 20 years of the 21st century. The results show that: (1) The area of grassland and unutilized land decreased, and the area of other land use types increased. (2) Distinct variations in the average, slope, and interval distribution of ecological parameters across various land use types were evident. Particularly significant increases in ecological parameters were observed in cultivated land and forest. (3) The influence of land use and land cover change on ecological parameters was evident. The conversion of cultivated land, forest, and grassland into water bodies, constructive land, and unutilized land resulted in a significant decrease in ecological parameters. (4) The distinct climatic conditions resulted in heightened monthly variations in the ecological parameters. Significant monthly fluctuations in ecological parameters were observed for cultivated land, forest, grassland, and constructed land, while water bodies and unutilized land did not exhibit such variations. (5) The correlation between ecological parameters and climatic factors varied considerably in various land use types in different regions.

Constructing Rainfall Threshold for Debris Flows of a Defined Hazardous Magnitude

Debris flow can cause damage only when its discharge exceeds the drainage capacity of the prevention engineering. At present, most rainfall thresholds for debris flows mainly focus on the initiation of debris flow and do not adequately consider the magnitude and drainage measures of debris flows. These thresholds are likely to initiate numerous warnings that may not be related to hazardous processes. This study proposes a method for calculating the rainfall threshold that is related to a defined level of debris flow magnitude, over which certain damage may be caused. This method is constructed by using the transient rainfall infiltration analysis slope stability model (TRIGRS) and the fluid dynamics process simulation model (MassFlow). We first use the TRIGRS model to analyze slope stability in the study area and obtain the distribution of unstable slopes under different rainfall conditions. Afterward, the MassFlow model is employed to simulate the movement process of unstable slope units and to predict the depositional processes at the mouth of the catchment. Lastly a rainfall threshold is constructed by statistically analyzing the rainfall conditions that cause debris flows flushing out of the given drainage ditch. This method is useful to predict debris flow events of a hazardous magnitude, especially for areas with limited historical observational data.

Prolonged pattern coarsening in ion irradiated swinging Si substrates

Low energy ion beams are regarded as an effective means to spatio-temporally pattern a wide variety of surfaces that exhibit intriguing motifs. In this work, an unconventional technique of surface patterning has been demonstrated by studying the topographical evolution of a Si(100) surface in the presence of azimuthal sample swinging (Δϕ=20∘) under 500 eV Ar+irradiation with a polar incidence angle of 67°. A prolonged wavelength coarsening is also noticed for the swinging sample. Ripple anticoarsening is observed for static sample at high fluences. The linear and nonlinear growth regimes are found to bear a direct consequence of this unconventional geometry. Furthermore, two-dimensional slope distributions of the surface morphologies clearly indicate reduced asymmetries in the surface structures. The present geometry brings in an additional factor of differential exposure and redeposition effects in addition to the near-surface mass redistribution, the former being inconceivable in the static configuration. This study establishes the role of this unconventional yet simple method to precisely modify and control surface asymmetries and influence regime shifts.

Mapping of Groundwater Potential Zones in the Kuzhithuraiyar Sub Basin of Kodayar River, Kanniyakumari District, Tamilnadu: Using Analytic Hierarchy Process (AHP) and GIS

&#x0D; &#x0D; &#x0D; Groundwater plays a very important role for all living beings. It is decisive to have a scientific understanding of groundwater management since, with careful use and replenishment, groundwater may help solve issues. The distribution of groundwater tables, slope, land-form, drainage pattern, lithology, topography, geological structure, fracturing density, opening and connectivity of fractures, secondary porosity, and landuse landcover all affect the occurrence and efficiency of groundwater in an aquifer system. An essential tool for assessing, tracking and protecting groundwater resources is the integration of geospatial techniques such as Remote Sensing and Geographic Information System for the identification of groundwater potential zones. This study aims to find the groundwater potential zones using Analytical Hierarchy Process (AHP) and managing the resources by creating different thematic layers such as rainfall, geology, geomorphology, drainage density, soil, slope, lineament and landuse landcover (LULC) of the Kuzhithuraiyar sub basin of the Kodayar river in Tamilnadu using the application of geospatial technologies. The thematic maps for all the thematic layers have been prepared using tools such as Interpolation, contour lines, Classification in ArcGIS 10.8. Theme weight and class rank were assigned to different thematic layers in weighed overlay analysis. The results were validated through field work and groundwater potential map was created. The groundwater potential zonation mapping was done by the overlay analysis in ArcGIS 10.8 software. The obtained map was classified into four categories namely very high groundwater potential zone, high groundwater potential zone, medium groundwater potential zone and low groundwater potential zone. The North Eastern part of the basin is considered as low groundwater potential zone while the Southern portion has high groundwater potentiality. The low groundwater potential zone covers an area of 10.58 sq.km and high groundwater potential zone covers an area of about 388.37sq.km.This study will be helpful for useful groundwater management for different tenacities.&#x0D; &#x0D; &#x0D;