Range Of Slopes Research Articles

Detection of spatiotemporal changes in eco-environmental quality based on RSEI and SG filtering and its driving force analysis: a case study in Sichuan Province, China.

Landsat images were extracted using Google Earth Engine (GEE) platform and optimized by Savitzky-Golay (SG) filtering. The Remote Sensing Ecological Index (RSEI) method was used to analyze the eco-environmental quality in Sichuan Province in recent 20years. In addition, Theil-Sen median method and Mann-Kendall (MK) test were used to test the change trend of eco-environmental quality. Furthermore, drivers were evaluated by partial correlation analysis, 2D scatter plots, and t tests. The results showed that (1) in the past 20years, the eco-environmental quality of Sichuan Province was on the rise, and the eco-environmental quality in the western region was better than that in the eastern region. The eco-environmental quality was positively correlated with forest and grassland types, and negatively correlated with cultivated land and urban and rural construction land types. (2) The eco-environmental quality of Sichuan Province is linearly correlated with the digital elevation model, but poorly correlated with slope and slope direction. In the range of slope 0° ~ 9° and southeast direction, the eco-environmental quality is the worst. (3) The eco-environmental quality of Sichuan Province was most significantly affected by soil moisture and sunshine hours. The study can help us to understand and assess the health of ecosystems in Sichuan Province, provide a scientific basis for protecting and improving the environment, and guide the formulation and implementation of environmental protection policies.

Geodynamic hazard assessment for the archaeological park-museum by the town of Nikopol

This study was conducted to establish the engineering geological and hydrogeological conditions of the site and to assess the geodynamic hazard in relation to the design and construction of the archaeological park-museum and feeder road in the town of Nikopol (Bulgaria). The studied terrain occupies a river terrace and the foot of a delluvial slope with an elevation of 23-68 m. The tasks of the study are to identify: the geological structure of the slope, the area and depth range of the landslides, the location of the slip surface, the physical and mechanical properties of the engineering geological strata, the hydrogeological conditions, the current stability of landslides, the change of slope stability under the action of various factors. The ground investigation includes analysis of archival and published information on the area; geodetic survey of the landslide; engineering geological mapping; exploratory boreholes; geophysical surveys using the VES method; testing of soil and water samples; compilation of longitudinal engineering geological profiles and slope stability analysis using the computational models. To the south of the study site the slope is affected by an ancient landslide with a volume of about 30 million m3 developed on the right valley slope of the Danube River in the section between the plateau and the river terrace. Consistent landslides occur in its lower part. Slope stability calculations show that the landslides are triggered by a rise in the groundwater level, an earthquake and undermining of the slope base. Rock-falls has developed on the steep rock slopes, composed of moderately to highly weathered and fractured cherty and glauconitic limestones. The size of the rockfall blocks is in the range 0.3-0.8 m3 and their transport distance reaches from 10 m to 50 m from the base of the slope. Stabilization measures and facilities are proposed to strengthen the landslides and rockfalls in the considered section of the slope. For the landslides it is proposed to implement a counterfort embankment on which to build the feeder road, drainage ribs and drainage ditches. For protection of the buildings from collapsing rock debris, an anchored high-strength net is recommended. The design takes into account the trajectory of the falling blocks and their kinetic energy. For monitoring the condition of the landslides and rockfalls, as well as for evaluating the effectiveness of the implemented strengthening, drainage and coastal protection structures, a control and measurement system for regime observation was built.

Investigating Sampling Bias in Seismological Research Through Secondary Variable: Insights from VS30 Datasets of Mainland China, Japan, Türkiye, and Taiwan

Abstract Sampling bias is an inevitable issue in seismological research, especially in collecting seismic site condition data due to operational constraints. It impacts data representativeness and subsequent model performance. Previous researches give insufficient consideration to this issue. Some researches worked on raw data directly. Some others used conventional declustering methods that rely on data spatial distribution and proved to be ineffective. This study investigates sampling bias in seismological research by employing a debiasing method that incorporates secondary variables, focusing on VS30 datasets from mainland China, Japan, Türkiye, and Taiwan. Quantifying analysis showed that, when considering topographic slope as the secondary variable, the sampling biases in the mainland China and Taiwan dataset are more pronounced. When examining the secondary variable of geology age, the sampling biases in the Japan and Türkiye datasets that are not readily discernible through visual inspection of spatial distributions become apparent. By investigating the sampling bias of the Türkiye and mainland China dataset using semivariogram as the secondary variable, this study reveals hidden bias within the Türkiye dataset, despite its well-distributed appearance. This finding further illustrates the limitations of relying solely on spatial distribution to detect sampling bias. In addition, the study examined the impact of sampling bias on resulting models. The topographic slope-based VS30 proxy models of debiased data in the four regions demonstrate significant effects of debiasing on modeling outcomes. Notably, the debiased models exhibit a homogenized trend comparing to original models in the low topographic slope range, indicating the possibility of a globally consistent relationship.

METHODOLOGY FOR NUMERICAL MODELING OF DETERMINING THE VALUES OF CONDITIONAL PROBABILITIES OF HITTING AIR TARGETS WHEN FIRING A MISSILE WITH A TELEVISION OPTICAL SIGHT OF A COMBAT VEHICLE

The article presents a methodology for numerical modeling of determining the values of conditional probabilities of hitting air targets when firing a missile with a combat vehicle's television optical sight. The conditional probabilities of hitting air targets are associated with the sloping range to the far limit of the kill zone of an anti-aircraft missile system. The effectiveness of the use of an anti-aircraft missile system with a television optical sight depends on the plane of air targets, the picture plane of firing, and the conditions of missile firing. The following factors were taken into account in the modeling: the color of air targets, the meteorological range of atmospheric visibility, the quality of combat performance of the combat vehicle personnel, and sunlight. The calculations take into account the technical characteristics of the stations and systems of the combat vehicle and missile. The values of the first kind of missile firing errors are presented, namely, the systematic components of the first kind of missile firing errors and their standard deviations of errors depending on the far limit of the kill zone of the anti-aircraft missile system. It is shown that the systematic component of the dynamic first-order missile firing errors increases due to the maneuvering of air targets, provided that the standard deviation of the first-order missile firing errors during the maneuvering of air targets remains unchanged. The values of the standard deviations of the first kind of missile firing errors depending on the far limit of the kill zone of the anti-aircraft missile system are given, taking into account the influence of interference on the combat vehicle's reconnaissance radar station and optical interference on the channel of the combat vehicle's television optical sight. The parameters of the first kind of missile firing errors, i.e., the values of the probabilities of the missile passing through the “tube” of the required radius of operation of the missile's radio fuse, were found. The values of the second kind of missile firing errors, namely the conditional probabilities of the missile's radio fuse, are considered. The mathematical expectation of the random value of the radius of the missile's radio fuse, which corresponds to air targets under the specified conditions, is established. The values of conditional probabilities of hitting various air targets under various conditions of firing at the far edge of the kill zone of the anti- aircraft missile system are analyzed and calculated. The obtained analytical expressions for the numerical modeling technique and the corresponding graphical material are presented.

Mapping the anisotropic Galactic stellar halo with blue horizontal branch stars

We used Legacy Survey photometric data to probe the stellar halo in multiple directions of the sky using a probabilistic methodology to identify blue horizontal branch (BHB) stars. The measured average radial density profile follows a double power law in the range 5 < rgc/kpc < 120, with a density break at rgc ≈ 20 kpc. This description, however, falls short, depending on the chosen line of sight, with some regions showing no signature of a break in the profile and a wide range of density slopes, such as an outer slope −5.5 ≲ αout ≲ −4, pointing towards a highly anisotropic stellar halo. This explains, in part, the wide range of density profiles reported in the literature owing to different tracers and sky coverage. Using our detailed 3D stellar halo density map, we quantified the shape of the Pisces overdensity associated with the transient wake response of the Galaxy’s (dark) halo to the Large Magellanic Cloud (LMC). Measured in the LMC’s coordinate system, Pisces stands above the background, is 60° long and 25° wide, and is aligned with the LMC’s orbit. This would correspond to a wake width of ∼32 kpc at ∼70 kpc. We do not find a statistically significant signature of the collective response in density as previously reported in the literature measured with K giant stars, despite our larger numbers. We release the catalogue constructed in this study with 95 446 possible BHB stars and their BHB probability.

Investigating Layered Topological Magnetic Materials as Efficient Electrocatalysts for the Hydrogen Evolution Reaction under High Current Densities

Despite considerable progress, high-performing durable catalysts operating under large current densities (i.e., >1000 mA/cm2) are still lacking. To discover platinum group metal-free (PGM-free) electrocatalysts for sustainable energy, our research involves investigating layered topological magnetic materials (semiconducting ferromagnets) as highly efficient electrocatalysts for the hydrogen evolution reaction under high current densities and establishes the novel relations between structure and electrochemical property mechanisms. The materials of interest include transition metal trihalides, i.e., CrCl3, VCl3, and VI3, wherein a structural unit, the layered structure, is formed by Cr (or V) atoms sandwiched between two halides (Cl or I), forming a tri-layer. A few layers of quantum crystals were exfoliated (~50−60 nm), encapsulated with graphene, and electrocatalytic HER tests were conducted in acid (0.5M H2SO4) and alkaline (1M KOH) electrolytes. We find a reasonable HER activity evolved requiring overpotentials in a range of 30–50 mV under 10 mA cm−2 and 400−510 mV (0.5M H2SO4) and 280−500 mV (1M KOH) under −1000 mA cm−2. Likewise, the Tafel slopes range from 27 to 36 mV dec−1 (Volmer–Tafel) and 110 to 190 mV dec−1 (Volmer–Herovsky), implying that these mechanisms work at low and high current densities, respectively. Weak interlayer coupling, spontaneous surface oxidation, the presence of a semi-oxide subsurface (e.g., O–CrCl3), intrinsic Cl (or I) vacancy defects giving rise to in-gap states, electron redistribution (orbital hybridization) affecting the covalency, and sufficiently conductive support interaction lowering the charge transfer resistance endow the optimized adsorption/desorption strength of H* on active sites and favorable electrocatalytic properties. Such behavior is expedited for bi-/tri-layers while exemplifying the critical role of quantum nature electrocatalysts with defect sites for industrial-relevant conditions.

Analysis of the coupling and coordination between soil erosion and land use in the Northeastern black soil region of China: a case study of Lishu County

Lishu County, which is located in the black soil region of Northeast China, represents a key site for the analysis of soil erosion intensity. This study offers a scientific foundation for the development of targeted soil and water conservation strategies within the region. The Revised Universal Soil Loss Equation (RUSLE) was employed to compute the soil erosion modulus in Lishu County, with the objective of conducting a quantitative analysis of the temporal and spatial distribution patterns of soil erosion. Additionally, the changing characteristics of soil erosion were examined from the perspectives of land use types and slope variations. The Generalized Connectivity Causality Model (GCCM) was utilized to identify the causal relationship between soil erosion and land use types through the reconstruction of state space and cross-mapping predictions. (1) Soil erosion in Lishu County between 2000 and 2020 predominantly exhibited mild to moderate levels, characterized by patchy and sporadic erosion, with relatively severe occurrences in the northern and central regions. (2) Soil erosion was correlated with land use and slope variations, with more than 90% of erosion incidents transpiring in cultivated land areas. The 3°-5° slope range in Lishu County emerged as a focal point for erosion, necessitating targeted prevention and control measures. (3) The GCCM model illustrated a discernible causal relationship between soil erosion and land use, revealing mutual influences between the two factors. Between 2000 and 2020, both the area and intensity of soil erosion in Lishu County exhibited an initial increase, followed by a subsequent decrease. This suggests an overall trend of amelioration in soil erosion conditions. However, notable spatial disparities persist in the erosion distribution across the region.

A new interpretation of mode I interlaminar fracture in layered materials

Interlaminar crack propagation in layered materials, such as composites, is still a not fully understood phenomenon in fracture mechanics. Experimental observations reveal a broad spectrum of crack propagation velocities during the interlaminar fracture of layered materials under varying loading conditions and rates. While there have been numerous studies examining interlaminar crack propagation under quasi-static, fatigue, and more recently, high-speed loading, there has been a notable lack of endeavors to present and interpret crack growth data within a unified framework. To this direction, we present a new interpretation of interlaminar crack propagation data acquired from a broad test campaign under various mode-I loading conditions (quasi-static, fatigue and high-speed). We connect the crack tip velocity to the rate of change of the SERR to propose a new equation/model that shows potential in presenting and explaining the variety of experimental crack growth data. This correlation arises from a simple mathematical analysis of the rate of change of the SERR using the chain differentiation rule. Subsequently, it is further substantiated by experimental evidence, in an effort to accommodate results from various experiments under a unified description. A robust correlation of the test data is established through a range of slopes which are proven -experimentally- to be characteristic constants of the mode-I interlaminar fracture of a specific material system.

Regional tidal modeling on the European coast using tide gauges and satellite altimetry

The study investigates sea-level measurements along the coastal area of Europe for the 60-year (1961–2020) time span. Linear and quadratic modeling of tide gauge measurements showed an almost positive rate of trend of sea-level rise (0.09 to 3.6 mm/yr) and low acceleration (−0.05 to 0.40 mm/yr2). A least-squares harmonic estimation tidal modeling was carried out to estimate frequency (cycles per day) for a certain period. The smaller and higher tidal frequencies of these stations indicate their stability in terms of their surface variation. We used the 1993–2020 satellite altimetry data from the nearest grid points of the tide gauge station. The correlation coefficient between observed and satellite altimetry (lowest 0.53 and highest 0.93) varies at each station. This happens because of many factors that can affect the large difference in the sea-level trend between the satellite-derived and tide gauge results. Finally, to implement a global reference system for physical heights, the offshore topographic slope direction and slope range with contour spacing from the sea to the associated coastline were analyzed using bathymetry data. The abrupt change in slope from the coastline toward the sea can be seen toward the east, west, and southeast on the European coast. This is also an important factor that affects the variation of sea level.

X-ray flux and spectral variability of the blazar OJ 287 with Suzaku

ABSTRACT We present analyses of Suzaku XIS light curves and spectra of the BL Lac object OJ 287 with observations positioned primarily around proposed recurrent optical outbursts. The first two observations were performed in 2007 April 10–13 (epoch 1) and 2007 November 7–9 (epoch 2) that, respectively, correspond to a low and a high optical state and which, within the binary supermassive black hole model for OJ 287, precede and follow the impact flare. The last three observations, made consecutively during 2015 May 3–9 (epoch 3), were during the post-impact state of the 2013 disc impact and are the longest continuous X-ray observation of OJ 287 taken before the optical outburst in 2015 December. Intraday variability is found in both the soft (0.5–2 keV) and hard (2–10 keV) bands. The discrete correction function analysis of the light curves in both bands peaks at zero lag during epochs 2 and 3, indicating that the emission in both bands was cospatial and emitted from the same population of leptons. Power spectral densities of all three light curves are red noise dominated, with a rather wide range of power spectrum slopes. These X-ray spectra are overall consistent with power laws but with significantly different spectral indices. In the 2015 observations the X-ray spectrum softens during the flare, showing an obvious soft X-ray excess that was not evident in the 2007 observations. We discuss the implications of these observations on the jet, the possible accretion disc, and the binary supermassive black hole model proposed for the nearly periodic optical flaring of OJ 287.

The velocity extraction and feature analysis of glacier surface motion in the Gongar region based on multi-source remote sensing data

The movement of glaciers plays a crucial role in environmental and geological processes, significantly influencing the formation and dynamics of ice bodies. This study leverages feature tracking technology to analyze optical and Synthetic Aperture Radar (SAR) remote sensing imagery, specifically GF-1 optical images and GF-3, Sentinel-1 SAR images, captured during the 2020 to 2021 ablation season in Gongar. The aim was to quantify glacier surface velocities and to evaluate the comparative effectiveness of different remote sensing modalities in capturing these dynamics. Our findings indicate a strong consistency in the spatial distribution of glacier surface velocities derived from diverse remote sensing data sources, with high-precision optical imagery (GF-1) yielding the most accurate velocity measurements, followed by Sentinel-1 SAR data. Notably, large glaciers in Gongar exhibited rapid movements, with an average velocity of 0.16 m/d, primarily at elevations between 4,500 and 6,500 m. The fastest velocities were recorded at approximately 4,500 m elevation. Glaciers with inclines ranging from 10° to 60° displayed the highest velocities within the 20°–30° slope range. It was observed that glaciers on the southeast slope moved faster, exhibiting the highest average surface velocity, in contrast to those on the west slope, which moved more slowly. The surface velocity of the ice tongue region of Krayaylak Glacier that the largest glacier in Pamir, was observed to be lower than 0.6 m/d, indicating a slow movement speed. The study also reveals that the effectiveness of different remote sensing data in detecting glacier velocity in Gongar, with high-resolution data more accurately capturing surface velocities in melting areas or those with slower movement. This study underscores the importance of multi-source remote sensing data in understanding glacier dynamics and contributes valuable insights into the mechanisms driving glacier movements.

Dynamics of a plant–pollinator network: extending the Bianconi–Barabási model

We study the dynamical assembly of weighted bipartite networks to understand the hidden mechanisms of pollination, expanding the Bianconi–Barabási model where nodes have intrinsic properties. Allowing for a non-linear interaction rate, which represents the seasonality of flowers and pollinators, our analysis reveals similarity of this extended Bianconi–Barabási model with field observations. While our current approach may not fully account for the diverse range of interaction accretion slopes observed in the real world, we regard it as an important step towards enriching theoretical models with biological realism.

MIDIS: Unveiling the Role of Strong Hα Emitters During the Epoch of Reionization with JWST

By using an ultradeep JWST/MIRI image at 5.6 μm in the Hubble eXtreme Deep Field, we constrain the role of strong Hα emitters (HAEs) during “cosmic reionization” at z ≃ 7–8. Our sample of HAEs is comprised of young (<35 Myr) galaxies, except for one single galaxy (≈300 Myr), with low stellar masses (≲109 M ⊙). These HAEs show a wide range of rest-frame UV continuum slopes (β), with a median value of β = −2.15 ± 0.21, which broadly correlates with stellar mass. We estimate the ionizing photon production efficiency (ξ ion,0) of these sources (assuming f esc,LyC = 0%), which yields a median value log10(ξion,0/(Hzerg−1))=25.50−0.12+0.10 . We show that ξ ion,0 positively correlates with Hα equivalent width and specific star formation rate. Instead ξ ion,0 weakly anticorrelates with stellar mass and β. Based on the β values, we predict fesc,LyC=4%−2+3 , which results in log10(ξion/(Hzerg−1))=25.55−0.13+0.11 . Considering this and related findings from the literature, we find a mild evolution of ξ ion with redshift. Additionally, our results suggest that these HAEs require only modest escape fractions (f esc,rel) of 6%–15% to reionize their surrounding intergalactic medium. By only considering the contribution of these HAEs, we estimated their total ionizing emissivity ( Ṅion ) as Ṅion=1050.53±0.45s−1Mpc−3 . When comparing their Ṅion with non-HAE galaxies across the same redshift range, we find that that strong, young, and low-mass emitters may have played an important role during cosmic reionization.

Atheroprotective WSS effects on human aortic endothelial cells in a new generation bioreactor

Abstract Funding Acknowledgements None. Background Luminal arterial endothelial cells are mainly aligned along the blood flow direction, whereas the in vitro endothelial cells (EC) showed heterogeneous distribution. In atherosclerosis the altered blood flow, acting on mechano-transduction, contributes to endothelial dysfunction and barrier disorganization. A low wall shear stress (WSS) has a pro-atherosclerotic effect, whilst elevated WSS is atheroprotective. Purposes Aim of this work is to study the primary human aortic EC cells (HAOEC) capability to acquire a distribution reminiscent of the luminal alignment under atheroprotective WSS using a prototypal new generation bioreactor. Methods We have developed a novel device compatible with culture inside standard sterile incubator, allowing to apply complex WSS patterns in controlled conditions. The bioreactor includes a sample housing and a parallel plate flow chamber and is controlled by a custom electronic interface actuating motor and pump. The cells were settled over PMMA supports and coating conditions were setup. Atheroprotective WSS patterns were tested. We compared HAOEC submitted to high flow (1.2 Pa for 24h) vs. ramps with different slopes (3h, 8h, 24h) followed by steady-state flow (1.2Pa for 24h, 48h). Viability and distribution of Acridine Orange-labelled HAOEC were assessed over bioreactor supports at both beginning and end of the experiments using fluorescence microscope. Hematoxylin/Eosin and Coomassie Blue staining were tested after the experiment to evaluate the shape and cell orientation (directionality FiJi plugin). Confocal microscopy on HAOEC labelled with Phalloidin–TRITC, anti-CD31/PECAM1-AlexaFluor488 and DAPI displayed the flow-related changes. Results HAOEC settled over naked sterile PMMA supports mainly detached under WSS, independently from the cell number. Coating with extracellular matrix components (i.e., human laminin, bovine fibronectin, chicken collagen type II, human collagen type I) showed the superiority of collagen type I to obtain homogeneously distributed, flow-resistant cell monolayers. In static condition, HAOEC on coated supports demonstrated ≥50% detachment within 24h, those submitted to a direct atheroprotective WSS of 1.2Pa almost completely detached. Consistently, to ramps with high slope (range 0.2-1,2Pa in 3h or 8h) followed by1.2Pa WSS corresponded 60%-90% cell detachment. Conversely, a 24h ramp (range 0.2-1,2Pa) followed by 24h or 48h of 1.2Pa WSS preserved the HAOEC monolayer adherence, and aligned cells were found. Microscopy comparative analysis of selected areas before/after WSS showed a partial spatial reorganization, with changes in the F-actin cytoskeleton and CD31 distribution. Conclusion We have optimized a protocol for studying HAOEC under atheroprotective WSS. In perspective further increasing the duration of the stimulus under constant WSS will achieve full alignment and provide a pseudo-physiologic model for multidirectional atherogenic WSS studies.

Giant sediment wave fields adjacent to debris-flow filled deep sea valleys: New evidence of cohesive flows transforming into dilute turbidity currents

Sediment waves are subaqueous sedimentary figures belonging to the supercritical flow domain and are of growing interest to the scientific community and industry. They are ubiquitously observed on the seafloor of world's oceans, as well as in the stratigraphic record imaged by marine seismic datasets. In this study we focus on the Cenozoic strata offshore Ivory Coast, where giant sediment waves developed at the base of slope range in height and wavelength: 10–100 m and 1–6 km, respectively. Sediment waves fields in this study developed simultaneously and adjacent to wide, rectilinear valleys, filled by mass-transport deposits. Thus, sediment waves serve as a rare example of large-scale deep-water cyclic steps formed through phase transformation (water entrainment and dilution) of laminar debris flows.The lithological nature of sediment waves can be estimated through the observation of polygonal faulting affecting the sediment waves fields, which suggest a dominant abundance of fine-grained material (clay and silt-prone). This study also shows that wide submarine valleys flanked by sediment waves do not necessarily correspond to sand-prone depositional systems, and that their potential to hold reservoir units for hydrocarbon exploration or CO2 storage should be evaluated with caution when in lower resolution datasets are used.

What a Puzzle! Unravelling Why UK Phillips Curves were Unstable

AbstractThe UK relationship between nominal wage inflation and the unemployment rate is unstable. Over sub‐periods of the last 160 years of turbulent data, Phillips curve slopes range from strongly negative, slightly negative, flat, slightly positive and strongly positive. Our constant‐parameter congruent model of real wages explains these instabilities, yet also implies a constant negative relationship between nominal wage inflation and the unemployment rate when corrected by its regressors. Disentangling these effects reveals that structural breaks in the real‐wage model's variables do not explain the instabilities, which instead occur during sub‐periods when some of its explanatory variables are insignificant.

Predicting Wildfire Ember Hot-Spots on Gable Roofs via Deep Learning

Ember accumulation on and around homes can lead to spot fires and home ignition. Post wildland fire assessments suggest that this mechanism is one of the leading causes of home destruction in wildland urban interface (WUI) fires. However, the process of ember deposition and accumulation on and around houses remains poorly understood. Herein, we develop a deep learning (DL) model to analyze data from a series of ember-related wind tunnel experiments for a range of wind conditions and roof slopes. The developed model is designed to identify building roof regions where embers will remain in contact with the rooftop. Our results show that the DL model is capable of accurately predicting the position and fraction of the roof on which embers remain in place as a function of the wind speed, wind direction, roof slope, and location on the windward and leeward faces of the rooftop. The DL model was augmented with explainable AI (XAI) measures to examine the extent of the influence of these parameters on the rooftop ember coverage and potential ignition.

Estimation of road cut slope stability along the national and state highway of Garhwal Himalaya (India) applying slope mass rating and kinematic analysis

Slope stability assessment of different road cut slopes has been conducted along the National Highway in Garhwal Himalaya, Uttarakhand (NH-34, NH-134, NH-7, NH-107 and a state highway from Dharasu to Tilwara). Slope instability issues in the Himalayan terrain are radically increasing due to high anthropogenic activities and rapid growth of urban centers since past years. Road networks in mountainous areas are the main source of transportation and socio-economic development. In this concerned study, forty (40) road cut slopes have been selected. These sites are selected based on lithology and structure. Diverse slope stability quantification methods along with various modes of failures have been systematically analyzed. The entire region falls under the tectonically active belt or the vicinity of the active fault zones that make the slopes inherently unstable. The Geological Strength Index (GSI) and Rock Mass Rating (RMR) have been applied for determination of slope conditions. Slope mass stability has been evaluated using Slope Mass Rating (SMR) index. The RMR rating ranges from 26 to 87 and the SMR values of forty (40) roads cut slopes range from 10 to 91. The kinematic analysis shows that most of the probable slopes failures are susceptible under planar and wedge failure. This study will definitely help to reduce the loss of life and property and also helps the ongoing constructional processes along the road section.

Ice base slope effects on the turbulent ice shelf-ocean boundary current

Abstract Efforts to parameterize ice shelf basal melting within climate models are limited by an incomplete understanding of the influence of ice base slope on the turbulent ice shelf-ocean boundary current (ISOBC). Here we examine the relationship between ice base slope, boundary current dynamics, and melt rate using 3-D, turbulence-permitting large-eddy simulations (LES) of an idealized ice shelf-ocean boundary current forced solely by melt-induced buoyancy. The range of simulated slopes (3-10%) is appropriate to the grounding zone of small Antarctic ice shelves and to the flanks of relatively wide ice base channels, and the initial conditions are representative of warm-cavity ocean conditions. In line with previous studies, the simulations feature the development of an Ekman boundary layer adjacent to the ice, overlaying a broad pycnocline. The time-averaged flow within the pycnocline is in thermal wind balance, with a mean shear that is only weakly dependent on the ice base slope angle α, resulting in a mean gradient Richardson number 〈Rig〉 that decreases approximately linearly with sinα. Combining this inverse relationship with a linear approximation to the density profile, we derive formulations for the friction velocity, thermal forcing, and melt rate in terms of slope angle and total buoyancy input. This theory predicts that melt rate varies like the square root of slope, which is consistent with the LES results and differs from a previously proposed linear trend. The derived scalings provide a potential framework for incorporating slope-dependence into parameterizations of mixing and melting at the base of ice shelves.

Preferential flow of phosphorus and nitrogen under steady‐state saturated conditions

AbstractRepeated broiler litter application on agricultural lands can cause nutrient enrichment of subsurface effluent, especially with the existence of preferential flow through soil macropores. Previous studies quantifying soil macropores have not attempted to establish a connection of soil macropore characteristics with the subsurface nutrient (nitrogen [N] and phosphorus [P]) losses, across different topographical locations in the field. This study investigated the effect of broiler litter application and preferential flow on subsurface nutrient transport (N and P) at different topographical positions (upslope, midslope, and downslope) in a no‐till pasture field located in Alabama, USA. Twelve intact soil columns (150 mm id and 500 mm length) were used, and the nutrient leaching measurements from laboratory experiments were linked to soil macropore characteristics quantified using X‐ray computed tomography image analysis and solute transport modeling. Treatments included surface broadcast broiler litter (5 Mg ha−1, on dry basis) and unamended control. Leachates were analyzed for dissolved reactive P (DRP), total P (TP), and nitrate + nitrite‐N (NO3− + NO2−–N). The bromide breakthrough curves provided evidence of preferential flow in all columns. Litter application significantly increased leachate P concentrations, and average TP and DRP concentrations were significantly higher in the leachate from upslope columns compared to those at downslope location. The NO3−–N concentrations in leachate exceeded the US EPA drinking water standard of 10 mg L−1 in all the treatment columns. The highest flow‐weighted mean concentrations of TP and DRP, at 2.7 and 2.5 mg L−1, respectively, were recorded in the upslope columns. Soil physicochemical properties and nutrient leaching losses varied substantially across topographical positions, indicating a need for variable litter application rates to reduce P build‐up and subsequent leaching in vulnerable locations within the field. The relevance of the effect of topographic position on nutrient leaching found in this study should be further tested by investigating a wider range of slopes and soil types in pastures.