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In this study, the Discrete Element Method (DEM) was employed as a computational approach to analyse the bulk behaviour of wheat (Triticum aestivum L., cv. 'Pionier') under compressive loading. A laboratory compression apparatus was utilised as a basis for the acquisition of data from compression tests. To ensure accurate DEM predictions, the physical, mechanical, and interaction properties of wheat kernels were experimentally determined for two different moisture contents (12.4% and 25.4% w.b.). Five particle models were constructed to represent the geometric shape of the kernel, with the model composed of five sub-spheres identified as the most suitable, ensuring an optimal balance between computational complexity and simulation accuracy. The bulk compression results from DEM simulations were compared to experimental data, revealing a good agreement for volumetric strain, bulk density increase, and bulk compressibility within the specified range of applicability. Simulations provided valuable insights into temporal and spatial variations of forces and deformations acting on individual particles, thereby enhancing the understanding of bulk behaviour at different compression levels. The moisture content was found to significantly affect the particle compressive forces, deformation capabilities, and bulk compression characteristics. In conclusion, this study demonstrated the great potential of DEM in predicting the bulk behaviour of wheat under compression, providing valuable information for practical storage and handling processes. • Bulk behaviour of wheat during compressive loading was studied using DEM. • DEM-relevant modelling parameters were determined experimentally. • Bulk volumetric strain, bulk density and compressibility were investigated. • Mechanical response of particles under bulk compression was analysed. • Moisture content effect on product properties and compression characteristics was examined. [ABSTRACT FROM AUTHOR]

We study characterizations of sincere modules, sincere silting modules and tilting modules in terms of various vanishing conditions. Let R be a perfect ring and T be an R-module. It is proved that T is sincere silting if and only if T is presilting satisfing the vanishing condition KerExt R 0 ≤ i ≤ 1 (T , −) = 0 , and that T is tilting if and only if KerExt R 0 ⩽ i ⩽ 1 (T , −) = 0 and Gen T ⊆ KerExt R 1 ⩽ i ⩽ 2 (T , −) . As an application, we prove that a sincere silting R-module T of finite projective dimension is tilting if and only if Ext R i (T , T (J)) = 0 for all sets J and all integer i ≥ 1 . This not only extends a main result of Zhang's paper [Self-orthogonal τ-tilting modules and tilting modules, J Pure Appl Algebra, 2022, 226: 106860] from finitely generated modules over Artin algebras to infinitely generated modules over more general rings, but also gives it a different proof without using Auslander-Reiten translations. [ABSTRACT FROM AUTHOR]

The exploitation of natural gas hydrates is in essence the process of hydrate dissociation from the solid phase into the gas and liquid phases, which is a complex problem involving phase transition and gas-water multi-phase flow. Permeability is a useful parameter for characterizing the flow capacity of sediments, and the pore-structure changes caused by hydrate dissociation make this parameter characterized by spatial and temporal evolution. Clayey silt sediments form the hydrate accumulation reservoir in the South China Sea, whose lithological characteristics (shallow buried deep, poor permeability, and low cementation) are unfavorable to fluid flow, leading to difficulties in the production prediction of clayey silt hydrate-bearing sediments. In this paper, the mutual feed-back mechanism between pore-structure and permeability during hydrate dissociation was clarified using the lattice Boltzmann model method. Core-scale seepage experiments were carried out to validate the dynamic evolution of permeability relationship. The permeability calculation module of Tough+Hydrate code was developed to quantitatively describe the evolution of this relationship, and the first hydrate production test in the Shenhu area was evaluated to validate the applicability of pore- and core-scale study at the site scale. This study clarifies the dynamic evolution mechanism of permeability during hydrate dissociation, and establishes a permeability evolution model in a S-shape suitable for clayey silt hydratebearing sediments. [ABSTRACT FROM AUTHOR]

Tolerably mobile subsea foundations are designed to slide on the seabed to accommodate flowline thermal expansion and contraction, and are a potential alternative to conventional (fixed) foundations. During the periodic sliding events that occur during operation, soil berms form at the extremities of the foundation footprint. The size of the berm increases throughout the life-cycle of the foundation, leading to increasing peak sliding resistance. This may hinder mobility of the foundation and overstress the pipeline connections that the foundation is designed to support. Equally, the berms may be relied on to reduce sliding and thus minimize settlement of the foundation, which can also overstress pipeline connections. This paper analyses the mechanism leading to berm accumulation and its mobilisation, also addressing periodic remoulding and reconsolidation of the sediment in the berm. A framework is proposed to predict the accumulation of soil berms and the resulting peak sliding resistance, and is validated by eight centrifuge model tests performed on a kaolin clay and a calcareous silt. [ABSTRACT FROM AUTHOR]

There are relatively few experimental studies on the hydromechanical and critical state behaviours of unsaturated silty sand. In this paper, suction-controlled, consolidated, drained triaxial shear tests were conducted on silty sand under saturated (net confining pressures of 100, 200, 300 and 400 kPa) and unsaturated (suctions of 30, 100 and 200 kPa and net confining pressures of 100, 200 and 300 kPa) conditions. For unsaturated silty sand, the effects of dry density, matric suction and net confining pressure on the hydromechanical and critical state behaviour were investigated, and the critical state parameters were obtained. The main findings for unsaturated silty sand included shear shrinkage at low dry density (1·6 g/cm3) and dilatancy at higher density (1·96 g/cm3). The peak shear strength was positively correlated with dry density, matric suction and net confining pressure. The critical state volumetric strain and critical state degree of saturation were negatively correlated with dry density and matric suction but positively correlated with net confining pressure. A new dilatancy equation that includes the state parameter for unsaturated silty sand was established. A unique critical state line passes through the origin in the effective stress p ∗ –deviator q plane, and its slope is the saturated critical state stress ratio M s . In the lnp*–v plane ( v is the specific volume), the critical state lines corresponding to different matric suctions are parallel. [ABSTRACT FROM AUTHOR]

A discrete-continuous (PFC–FLAC) coupling method was used in this study to simulate laboratory triaxial tests with soybean granular material. The mesoscopic mechanical parameters of the soybean granular material were calibrated by comparing them with actual laboratory test results, and the validity of the modeling method was verified. Subsequently, the particle motion law and mechanical mechanism of the soybean granular materials were analyzed based on the particle displacement field, velocity field, and force chain network. The results showed that the coupled PFC–FLAC method could better describe the macroscopic stress–strain relationship, deformation damage characteristics, and shear strength mechanical indexes of soybean granular materials. With increasing confining pressure (50–200 kPa), the bulging deformation of the specimens changed from uniform to concentrated but uneven. The particle contact number and maximum particle contact stress increased by 19.3 and 48%, respectively. Additionally, variations of the macroscopic properties of the specimens with microscopic parameters were revealed. Under the same conditions, the change in the peak stress of the specimen was proportional to the interparticle friction coefficient. Moreover, the slope of the stress–strain curve increased gradually with an increase in the effective modulus. [ABSTRACT FROM AUTHOR]

Engineering practices indicate that stratum hydraulic conductivity (SHC) has a significant influence on deep excavations. However, this influence has been ignored in previous studies with undrained analyses. In this study, a numerical model, combined with the verified hydromechanical coupled method, is established to investigate the effect of SHCs on the performances of deep excavations. Excavation deformation, pore-water pressure, lateral pressure, and the stress evolution process are presented, respectively, to illustrate these influences. In addition, the model of a beam on an elastic foundation is employed to interpret the influential mechanism of SHCs on excavation deformations. Analysis results indicate that excavation deformations increase significantly with the increase in SHCs from 1 × 10−7 to 1 × 10−5 cm/s (i.e., the range of SHCs of soil containing silt). The influence of SHCs on excavation deformations is mainly attributed to the variation of effective stress levels on the excavated side. As SHC increases, the change in the resultant force of the total stress acting on the retained side of the wall, as loads, can be ignored, while the resultant force of the effective stress acting on the excavated side of the wall, as resistances, decreases dramatically. These findings emphasize the importance of accurate determination of the SHC of strata containing silt. Engineering practices indicate that stratum hydraulic conductivity (SHC) significantly affects the performances of deep excavations in Shanghai soft deposits. Constructions in the first aquitard (AdI) have been involved in the many deep excavations in Shanghai, China, and therefore, identifying the effects of the SHC of AdI on deep excavations can further ensure the safety of constructions. In this study, it is found that excavation deformations increase significantly as the SHC of AdI increases from 1 × 10−7 to 1 × 10−5 cm/s (i.e., the SHCs in soil containing silt). This finding indicates that valuing the SHC of AdI containing silt requires utmost caution, and adopting appropriate methods such as dewatering can significantly decrease excavation deformations. [ABSTRACT FROM AUTHOR]

Assume that B is a finite dimensional algebra, and A = B [ P 0 ] is the one-point extension algebra of B using a finitely generated projective B-module P0. The categories of B-modules and A-modules are connected via two adjoint functors known as the restriction and extension functors, denoted by R and E , respectively. These functors have nice homological properties and have been studied in the category mod- A of finitely presented modules that we extend to the category Mod- A of all A-modules. Our main focus is to investigate the behavior of important subcategories (tilting and τ-tilting subcategories) and objects (finendo quasi-tilting modules, silting modules, and cosilting modules) under these functors. [ABSTRACT FROM AUTHOR]

We provide a technique to glue simple-minded collections along a recollement of Hom-finite Krull-Schmidt triangulated categories over a field. This gluing technique for simple-minded collections is shown to be compatible with those for gluing bounded t -structures, silting objects, and co- t -structures in the literature. Furthermore, it also enjoys the properties of preserving partial order and commuting with the operation of mutation. [ABSTRACT FROM AUTHOR]

The shear creep characteristics of the contact surface between the permafrost and the structure play an important role in the study of the law of deformation and the measures for the prevention and control of pile foundations. In order to study the creep law and the development tendency of the contact surface between permafrost and concrete, it is necessary to establish an accurate creep model. In this study, based on the Nishihara model, a nonlinear element and damage factor D were introduced to establish an intrinsic model of permafrost-concrete contact surfaces considering the effect of shear stress. Creep tests with graded loading of concrete and frozen silt with different roughness at -1°C were conducted using a large stress-controlled shear apparatus. The adequacy of the model was checked using the test data and the regularity of the parameters of the model was investigated. The results show that the creep curves of the contact surface obtained with the improved Nishihara model agree well with the test results and can better describe the whole process of creep of the contact surface of frozen concrete. The analysis of the experimental data shows that: the roughness of the concrete has an inhibiting effect on the creep deformation of the contact surface, When the roughness R varies from 0 mm to 1.225 mm, the specimen corresponds to a long-term strength of 32.84 kPa to 34.57 kPa. For the same roughness and creep time, the creep deformation of the contact surface is more significant with the increasing shear stress τ. The results of the study can provide a theoretical basis for the design and numerical simulation of pile foundations in permafrost regions. [ABSTRACT FROM AUTHOR]

The use of natural river silt treated as a 'waste material' has become the focus of research in the Yellow River flooded area, especially in the field of highway engineering. It is therefore of great significance to study the deformation and stiffness degradation of Yellow River silt (YRS) under long-term cyclic loads. To this end, a series of undrained cyclic triaxial tests on YRS for a large number of cycles (10 000) was carried out using a triaxial apparatus and the effects of confining pressure and cyclic stress ratio on the resilient strain of the YRS were explored. The critical cyclic stress and the critical cyclic stress ratio between the plastic shakedown state and incremental collapse state of the YRS were determined, and the modulus-softening behaviour of the YRS was assessed. The results of this study not only provide theoretical support for the long-term engineering performance of YRS, but also provide theoretical guidance for the cyclic response of all similar types of subgrade soils. [ABSTRACT FROM AUTHOR]

The shear mechanical properties of rock under high confining stresses are required in deep underground construction projects for stability evaluation. This paper tested the sandstone shear properties under high confining pressures by a novel triaxial direct shear device with a self-balancing structure for both low and high confining pressure. The triaxial direct shear experiments on Zigong sandstone from a deep tunnel were carried out to evaluate its strength and deformability. Our experimental results suggested that the shear stress-displacement curves exhibited two distinct characteristics under different confining pressures. The damaging stage occurs initially and turns wider in the shear stress-displacement curve as the confining pressure exceeds the threshold stress. The confining pressure threshold of Zigong sandstone is observed to be 10–20 MPa. Meanwhile, a statistical damage model based on Beta distribution was proposed to describe the shear stress (cohesion contribution) during the whole shearing process, which demonstrates better prediction performance than previously existing models, especially under high confining pressures. This study provides important insights into the high-pressure induced rock shear properties and sheds light on the engineering stability assessment under high stress of tunnels. [ABSTRACT FROM AUTHOR]

In this article, steel slag was added into the marine silt to improve its dynamic properties. The characteristics of marine silt that can be studied by XRD, BET surface area, SEM, and FTIR were first described. Then, the influence of the sample density, water content, waste steel slag content, and the confining pressure on the dynamic shear modulus G and damping ratio λ was discussed by conducting resonant column tests. The results illustrated that the dynamic characteristics of the marine silt-steel slag admixtures were considerably improved. Additionally, G increased with the increasing steel slag content and λ increased with the decreasing steel slag content. Moreover, a dynamic model of the admixtures was developed based on the Hardin–Drnevich model. Furthermore, by comparing the dynamic characteristics of the admixtures with Nanjing sand, Fujian sand, Kiyohoro silty clay, and Wenzhou marine clay, it was found that the improved admixtures may be a more suitable geofiller in geotechnical engineering. [ABSTRACT FROM AUTHOR]

Let R be a ring with unit. In this short note, we establish a bijection between certain equivalence classes of silting complexes in the derived category D(R) and equivalence classes of 2-silting objects in some abelian category. [ABSTRACT FROM AUTHOR]

To reveal the mechanism of the influence of the curing temperature on the strength of lime activated fly ash-GGBS cured silt soil, the curing of dredged silt was carried out by using fly ash and GGBS as the curing agent and lime as the activator. Unconfined compressive strength (UCS) experiments were carried out, and the micro-analysis of the cured silt was carried out by experimental methods including scanning electron microscope (SEM) tests, X-ray diffraction (XRD), etc. to reveal the mechanism of the curing temperature on the dredged silt. According to the test results, the hydration reaction and pozzolanic reaction between lime-fly ash-GGBS and silt soil were promoted with the increase of the curing temperature. when the curing temperature of the sample reached 40 ℃, a large amount of gel products such as hydrated calcium aluminate (C–A–H) and hydrated calcium silicate (C–S–H) were generated, which enhanced the bonding force between soil particles and filled up the inter-particle pore space, thereby improving the UCS of the sample. The results of SEM confirmed that C–A–H and C–S–H were the main substances for the construction of cured silt skeleton. C–S–H and C–A–H were detected by XRD. The results of the study fill the gap in the effect of curing temperature on the direction of lime-activated fly ash-GGBS cured silt soil. [ABSTRACT FROM AUTHOR]

One of the challenges of storing hydrogen in saline aquifers is the possible geochemical reactions between host rock, formation solution, and hydrogen. This study investigated the effect of hydrogen treatment on the mechanical properties of sandstone samples from Hulett member of Sundance Formation, a potential underground hydrogen storage host in Wyoming, USA. Cylindrical specimens were treated with brine, brine+50%H 2, and brine+100%H 2 for two weeks at a pressure of 15 MPa and a temperature of 83 °C. X-ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), uniaxial compression, and triaxial compression tests were conducted on specimens. Results showed that specimens treated with brine+50%H 2 and brine+100%H 2 , on average, exhibited 24 and 41% lower peak strength, respectively, compared to that of specimens treated with the brine. XRD results showed a decrease in dolomite and clay content of specimens after exposure to hydrogen, causing degradation of the mechanical and elastic properties of the specimens. • The effect of hydrogen on the mechanical properties of Hulett sandstone was investigated. • Dolomite and clay dissolution was observed after the treatment with hydrogen. • Specimens treated with hydrogen on average showed 41% lower strength. • An average 43% decrease in elastic modulus was observed after hydrogen treatment. [ABSTRACT FROM AUTHOR]

Under the repeated action of aircraft taxiing load, the subgrade plastic deformation becomes the key factor affecting the service performance of the airfields when salinized silt is used to fill the subgrade. In this study, the dynamic triaxial tests were carried out on a region in the northern part of China to study the effects of different salt contents on the dynamic characteristics of silt under cyclic loading. A prediction model for the salinized silt dynamic strength with a plastic strain of 4% as the failure criterion for the subgrade was thus proposed. It is found that with the increase of dynamic stress amplitude, the salinized silt plastic deformation transforms gradually from plastic deformation to incremental failure. The salt contents significantly influence the plastic strain and critical dynamic stress of silt. The strength of the salinized silt specimen is related to the ion concentration in the soil pores and the arrangement pattern of soil particles, as indicated by the progressive strength increase of the salinized silt at the low salt content of 1% and a further gradual decrease at high salt content. [ABSTRACT FROM AUTHOR]

This study investigates the responses of the depositional environments of Soda Lake sediments to climatic shifts from the Last Glacial Maximum to the Holocene epoch based on the results of major and trace elements of the North Soda Lake (NSL) NSL1A core. The NSL1A core records the sedimentary evolution of the Soda Lake watershed since at least 25 cal ka BP. Element analyses provide evidence that Soda Lake sediments are mostly derived from marine sequences in the Southern Coast Ranges of California. Variation in proxies for paleoweathering, paleoclimate, paleosalinity, paleoproductivity, paleoredox, and water depth is utilized to reconstruct the evolution of the sedimentary environment. The Chemical Index of Alteration (CIA) values indicate low to moderate chemical weathering in the sediment source regions. Paleoredox proxies indicate that the NSL1A core formed in a mainly subreduction environment. The NSL1A core is divided into four zones based on the results of the proxies. Zone 4 (5.0–5.8 m) of the sediment core indicates stable hydroclimatic conditions with low and constant sand and silt content, suggesting a warm and relatively humid environment. Zone 3 (3.35–5.0 m) represents the early half of the Last Glacial Maximum interval and a high lake stand. The elevated sand content suggests postflood events due to the northerly migration of westerly storm tracks. Zone 2 (1.075–3.35 m) reveals nuanced changes, including decreasing salinity, slight increases in wetness, detrital trace metals, and paleoproductivity. These subtle shifts suggest a multifaceted environmental evolution: a trend toward wetter conditions alongside a prolonged shift from cooler to warmer periods. Zone 1 (0.15–1.075 m) spans the Lateglacial to Holocene transition as well as Early and Middle Holocene, marked by significant hydrologic and ecologic variability including rapid warming during the Bølling–Allerød and rapid cooling linked to the Younger Dryas. [ABSTRACT FROM AUTHOR]

In the 1990s and early 2000s, it was recognized that marine muds consisted of sortable silt (63–8 µm) and aggregated (< 8 µm) particle suites and that these responded differentially to the hydraulic sorting process. Among the aggregated particle suite, the composition and hydraulic behavior of fecal pellets received the least attention. The present study focused on a tidal basin (~ 71 km2) of the East Frisian Wadden Sea (southern North Sea), in which the depositional patterns of both the sortable silt and aggregated mud fractions were compared with the aim of identifying similarities and/or dissimilarities. The results show essentially dissimilar trends, the sortable silt suite being characterized by two non-overlapping hydraulic populations, the aggregated particle suite by three overlapping populations with modal diameters separated by only a few microns. The depositional pattern of the latter is interpreted to suggest that the hydraulic populations relate to specific fecal pellet groups, each composed of a different discrete grain-size spectrum produced by different filter-feeding organisms. At the same time, it is demonstrated that the distribution of organic matter is closely linked to the aggregated (< 8 µm) particle suite. The CaCO3 content, by contrast, is linked to the mud fraction by a power relationship, the large data scatter suggesting multiple sources. Budget calculations show that the standing stock of mud in the uppermost 5 cm of the sediment in the tidal basin amounts to ~ 0.461 × 106 tons (9.78% of the total sediment), of which ~ 31.3 × 103 tons (0.67% of the total sediment) are contributed by organic matter. [ABSTRACT FROM AUTHOR]

This paper presents an easy to operate time-dependent, two-dimensional vertical model for the simulation of sand and mud concentrations, transport, and morphodynamic bed evolution in conditions with combined currents and waves. The basic model equation is the advection–diffusion equation for sediments including flow velocities, sediment mixing coefficients, and the settling velocity. The vertical distribution of the sediment mixing coefficient is described by fairly simple and flexible expressions based on flow and wave parameters with user-specified coefficients for calibration of results. The settling velocity is constant or dependent on the sediment concentration to represent mud flocculation and hindered settling processes based on input parameters. The bed boundary condition is modeled by a bed concentration as a function of the bed-shear stress due to currents and waves. The model is valid for sand concentrations and for low and high mud concentrations including fluid mud concentrations. The numerical SUSTIM2DV model has been used to simulate sand and mud transport and bed level changes in dredged (shipping) channels. The model is valid for perpendicular and oblique flow across a dredged channel. The channel slopes should not be too steep (1V:7H or milder), because logarithmic velocity profiles are used. Results of various validation cases of channel deposition of sand, silt, and (fluid) mud in tidal conditions with and without waves are presented. The effect of channel geometry is specifically addressed. The numerical model has also been used to derive sediment trapping factors, which can be used in simpler channel deposition models. [ABSTRACT FROM AUTHOR]

To achieve integrated resource utilization of graphite tailings to improve their water-holding capacity, river silt and cow dung powder were added to graphite tailings as organic matter improvers. Improver ratios were designed using 4 g cow dung powder and 20, 30, and 50 g river silt. Soil–water characterization tests were performed using a combined tensiometer and filter paper method based on optimum density measurements. Analysis of the influence of river silt dosing on the soil–water characteristic curves of improved graphite tailing specimens was performed with data fitting using the Van Genuchten model. Here, we investigated the effect of river silt dosing on the internal pore structure and water-holding capacity of modified graphite tailing samples and verified the applicability of the model to graphite tailings. Our results demonstrate that the organic matter improver incorporated into graphite tailings can improve the internal structural compactness of graphite tailings, improving the water holding capacity. With an increase in river silt dosage, the saturated water content is larger, and the residual water content increases and then decreases. When river silt dosage is 30 g, the residual water content is the highest at a value of 3.32%. The van Genuchten model was highly accurate for assessing the graphite tailings. With an increase in river silt doping, the internal pore space first decreased and then increased, and the internal structure gradually became compact and loosened. The internal structure was in the optimal state in the experimental study when the dosage of cow dung powder was 4 g and the dosage of river silt was 30 g. The water holding capacity was optimal at this time. The results of this study provide a theoretical foundation for graphite-tailing-based mine reclamation and play a guiding role in exploring the value of the hydraulic characteristic index parameters when applying graphite tailings engineering. [ABSTRACT FROM AUTHOR]

When backfilling narrow spaces, controlled low-strength materials (CLSM) can be used to achieve an effective backfilling effect. The pipeline engineering in Yahnghe Avenue of Suqian, China, provides a favorable on-site condition for the use of CLSM. However, no guidance exists for the determination of the material mixture ratio of CLSM for this geological condition. Laboratory tests were performed to investigate the basic physical parameters of excavated soil and the optimal mixture ratio of CLSM. Results indicate that the sand and silt account for 29.76% and 57.23% of the weight of excavated soil, respectively. As the water content increases (from 40% to 50%), the flowability of the CLSM approximately shows a linear increase (slumps values from 154.3 mm to 269.75 mm for 9% cement content), while its compressive strength shows a linear decreasing trend (from 875.3 KPa to 468.3 KPa after curing for 28 days); as the cement content increases (from 6% to 12%), the flowability approximately shows a linear decreasing trend (from 238.8 mm to 178.5 mm for 45% water content), while the compressive strength shows a linear increasing trend (from 391.6 KPa to 987.6 KPa after curing for 28 days). By establishing the relationship between compressive strength/flowability and the water–cement ratio, the optimal material ratio is determined to be 9% cement content and 40–43% water content. The engineering application results indicate that the use of CLSM can achieve efficient and high-quality backfilling effects for pipeline trenches. The findings of this research may provide a reference for the application of CLSM in fields with similar geological conditions. [ABSTRACT FROM AUTHOR]

A viscoplastic constitutive model is developed to describe the viscoplastic behavior of unsaturated soils. The proposed model accounts for the stain‐rate and suction effects on yield by adopting an unsaturated isotach concept. The nonstationary flow surface theory (NSFS) is applied for modeling the viscoplastic behavior, with the yield surface which can evolve with the viscoplastic strain, viscoplastic strain rate and suction. Meanwhile, the progressively hardening concept is adopted for reproducing the viscoplastic behavior of soil at an over‐consolidated state. For the validation, a series of loading conditions are considered based on the data from the literature. Results show that the proposed model is able to reproduce the main viscoplastic behaviors of unsaturated highly compacted Gaomiaozi (GMZ) bentonite, Glenroy silt and Qianjiangping landslide (QL) soil, including CRS compression tests, rate‐dependent triaxial shear tests, and triaxial creep tests. [ABSTRACT FROM AUTHOR]

Aeolian sediments accumulated along the desert-loess transition zone of the Tengger Desert include heterogeneous textures and complex component structures in their grain-size distributions (GSD). However, the sources of these aeolian sediments have not been resolved due to the lack of large reference GSD sample datasets from adjacent regions that contain various types of sediments; such datasets could be used for fingerprinting based on grain-size properties. This lack of knowledge hinders our understanding of the mechanism of aeolian dust releases in these regions and the effects of forcing of atmospheric circulations on the transportation and accumulation of sediments in this region. In this study, we employed a multi-scale grain-size analysis method, i.e., a combination of the single-sample unmixing (SSU) and the parametric end-member modelling (PEMM) techniques, to resolve the component structures of sediments that had accumulated along the desert-loess transition zone of the Tengger Desert. We have also analyzed the component structures of GSDs of various types of sediments, including mobile and fixed sand dunes, lake sediments, and loess sediments from surrounding regions. Our results demonstrate that the patterns observed in coarser fractions of sediments (i.e., sediments with a mode grain size of >100 μm) from the transition zone match well with the patterns of component structures of several types of sediments from the interior of the Tengger Desert, and the patterns seen in the finer fractions (i.e., fine, medium, and coarse silts with a modal size of <63 μm) were broadly consistent with those of loess sediments from the Qilian Mountains. The deflation/erosion of loess from the Qilian Mountains by wind was the most important mechanism underlying the production of these finer grain-size fractions. The East Asia winter monsoon (EAWM) played a key role in transportation of the aeolian dust from these source regions to the desert-loess transition zone of the desert. [ABSTRACT FROM AUTHOR]

The large-scale implementation of the Gully Stabilization and Land Reclamation (GSLR) project induces various failures of loess slopes due to excavation in Yan' an, China. However, the deformation and failure behavior of these excavated loess slopes have not been fully understood. In this study, field investigation was undertaken for analyzing the distributions and failure features of excavation-induced loess slope failures. It is found that plastic failure mainly occurs in Q3 loess layers and brittle failure in Q2. To understand the underlying failure mechanism, a series of triaxial shear tests were conducted on intact Q3 and Q2 loess samples that with different water contents, namely natural water content (natural), dry side of the natural value (drying 5%), and wet side (wetting 5%). The characteristics of stress-strain curves and failure modes of the samples were analyzed. Results show that the stress-strain curves of Q2 samples are dominated by strain-softening characteristics, while Q3 samples mainly exhibit strain-harden features except in the drying state. Correspondingly, shear failures of Q3 specimens are mainly caused by shear crack planes (single, X or V-shaped). For Q2 loess, the dominance of tensile cracks is observed on the surface of damaged specimens. These disclose the different failure modes of excavated slopes located in different strata, that is, the arc sliding failure of Q3 loess slopes and the stepped tensile failure of Q2 loess slopes, and are helpful in the design and management of the ongoing GSLR projects in the Loess Plateau. [ABSTRACT FROM AUTHOR]

An investigation of the Magdalenian occupation at Étiolles-Les Coudray (France) was conducted using geophysical methods. Based on ground-penetrating radar (GPR), electrical resistivity tomography (ERT), electromagnetic induction (EMI), and stratigraphic information, we present a reconstruction of the main sediment interfaces carrying the Magdalenian occupation. Étiolles-Les Coudray is one of the most important open-air campsites in the Paris Basin, where consecutive settlements distributed along the Hauldres stream were preserved by silts. The geoarchaeological goals were, in particular, the reconstruction of the ancient environment in which hunter–gatherers settled, providing spatialized known stratigraphies able to find an echo in the Seine Valley. Moreover, a focus on the capability of geophysical methods to detect archaeological features is also presented and discussed. We observed that the major reflections in the GPR records were generated from interfaces that have grain size variation: (1) the bottom of the Holocene colluvium and (2) the bottom of the upper Late Glacial silt. EMI and ERT show a very clear horizon associated with the upper Late Glacial silt, in some places even more clearly defined than with GPR. We confirmed the presence of a channel along the slope, placed under Locus 1, and a second channel of the same type globally following the paleotopography of Locus 2. We created a thickness map of the "beige sandy silt" and hypothesized a high probability of good preservation conditions of Magdalenian evidence. Finally, the detection of several localized diffraction hyperbolas in the GPR record offers the possibility to obtain the ground truth of the geophysical results in the near future and verify the nature (archaeological or geological) of these features. [ABSTRACT FROM AUTHOR]

Considering that methane hydrate formation in the water drainage line of natural gas hydrate production well could induces a series production issue, the experiments of methane hydrate equilibrium and formation in the water-methane-silt sand system are conducted to reveal the effect of silt sand on methane hydrate equilibrium and formation by using the low-temperature and high-pressure rocking reactors. In experiments, the silt sand mass concentrations are from 0 to 4wt% and the initial system pressures are from 4.38 to 12.14 MPa. The results from methane hydrate equilibrium experiments indicated that the silt sand could move the methane hydrate equilibrium curve to right about 1 °C, which a favorable environment for methane hydrate crystallization is created by silt sand. The correlations of methane hydrate equilibrium considering the effect of silt sand is obtained empirically. Moreover, the results from methane hydrate formation experiments showed that the silt sand could enhanced methane hydrate formation rates and promoted the water conversion ratios. The higher initial pressure conditions result in higher hydrate formation rates. The influencing mechanism of silt sand on the methane hydrate equilibrium and formation is considered to be similar with the nanofluid, which silt sand aggregate the heat and mass transfer process during methane hydrate crystallization. [ABSTRACT FROM AUTHOR]

The effective suction domain boundary directly affects the movement of seeds in air-suction seed-metering devices, thus the parameters involved can be optimised by analysing this pattern. However, relevant research on the effective suction domain boundary is scarce and vague. To further investigate the relevant theories of the effective suction domain boundary and the quantitative model, this study examined the effects of main factors on the boundary through single-factor experiments. By using computational fluid dynamics (CFD) software, numerical simulations of the flow field under different conditions demonstrated that the effective suction domain boundary of a cylindrical suction hole is larger, and that the main factors affecting changes of the boundary are the intensity and range of the pressure and velocity gradients around the seed and the change in the windward area of the seed. A boundary model of the effective suction domain was constructed by orthogonal experiment in the suction hole with a diameter of 3.5–5.5 mm and vacuum of 3–7 kPa, for quasi-spherical seeds with equivalent diameters in the range 5.74–7.92 mm and sphericity over 88.63 %. The accuracy of the boundary model was verified using quasi-spherical seeds such as soybean, pea, and Panax notoginseng seeds, and the relative errors were within 10 %. [Display omitted] • Effective suction domain boundary model constructed for quasi-spherical seeds. • A dynamic suction force measurement system was constructed. • Cylindrical suction hole had a larger effective suction domain boundary. • Intensity of the pressure and velocity gradients is the key reason. [ABSTRACT FROM AUTHOR]

This document discusses a research paper that explores the effects of viscoplasticity and strain softening on the stress-strain characteristics of saturated clays and plastic silts. The paper raises questions about the behavior of these materials in laboratory tests versus their behavior in situ. It also discusses the effects of anisotropy on the undrained shear behavior of clays and silts, presenting data from various tests to illustrate this behavior. The document highlights the behavior of quick clays under shear stress, noting that failure occurs at small axial strains followed by a rapid drop in shear stress and a gradual loss of strength. It emphasizes the importance of matching the rate of shear in laboratory tests to the rates that occur in the field and concludes that stability can be improved through ground treatment methods or supporting structures on piles. [Extracted from the article]

Regression models are presented to estimate the cyclic resistance of transitional silts as an alternative to semiempirical case history and stress history and normalized engineering parameter-based models using a database of cyclic laboratory tests on intact specimens. Expressions for the plasticity index (PI) dependent semilogarithmic slope, exponent b , of the curve describing the variation of cyclic resistance ratio (CRR) and number of loading cycles and the variation of number of equivalent loading cycles with b are developed for subduction zone earthquakes alongside corresponding magnitude scaling factors for use in cyclic failure assessments (i.e., liquefaction triggering and cyclic softening) within the simplified method framework. A PI, overconsolidation ratio, and shear strain-dependent model for the variation of CRR with N is presented to estimate cyclic resistance as a function of cyclic shear strain failure criteria ranging from 1% to 10%. The suite of models can be used together or separately to facilitate assessments of cyclic failure of, or plan cyclic laboratory test programs and/or calibrate constitutive models for, transitional silts in the absence of site-specific laboratory tests. [ABSTRACT FROM AUTHOR]

A new model was first proposed to estimate the ultimate bearing capacity of strip foundations under transient flows on the basis of the kinematic approach of limit analysis. To describe the collapse process, a symmetrical collapse mechanism was generated by discretization technique following the associated flow rule. A layer-wise summation method was developed to calculate the internal dissipation rate. The theoretical results of this paper are given in terms of some assumptions: (1) both soils and fluids considered in this study were regarded to be noncompressible; (2) the hydraulic conductivity in an unsaturated state was equal to that in a saturated state; and (3) the slope of the soil–water characteristic curve was assumed to be constant through the whole transient infiltration process. A series of comparisons with the theoretical results and experimental data were established to verify the reliability of the new approach proposed by this paper. Based on the numerical results and discussions, the key conclusion can be drawn as follows: the ultimate bearing capacities saw a relatively large decrease under transient flows, especially for strip foundations embedded in silt soil, however, the bearing loads for foundations in sandy soil tended to be steady throughout the whole infiltration process. [ABSTRACT FROM AUTHOR]

More than 90% of the natural gas hydrate resources are reserved as marine clayey silt sediments. It is of great significance to efficiently develop a clayey silt hydrate. At present, there are problems of low single well production and small depressurization range in its production test, which is still a long way from commercial exploitation. The combination of hydraulic fracturing technology and other methods such as depressurization method is regarded as one of the potential technical means to achieve the commercial exploitation of the hydrate. However, compared with shale gas reservoirs and coalbed methane reservoirs, clayey silt hydrate reservoirs have special mechanical properties, resulting in unique hydraulic fracturing processes. Therefore, it is necessary to study the fracture initiation and propagation laws of clayey silt hydrate reservoirs. To this end, we carried out large-scale (30 × 30 × 30 cm) true triaxial hydraulic fracturing experiments using a simulated material with similar mechanics, porosity, and permeability to clayey silt hydrate-bearing sediments. The effects of completion method, fracturing method, and fracturing fluid displacement on hydraulic fracture propagation of clayey silt hydrate-bearing sediments were studied. The results showed that a perforated completion can significantly increase the fracture reconstruction area and decrease the fracture initiation pressure compared to an open hole completion. Due to the small horizontal stress difference, it is feasible to carry out temporary plugging fracturing in clayey silt hydrate reservoirs. Temporary plugging fracturing can form steering fractures and significantly improve fracture complexity and fracture area. Increasing the fracturing fluid displacement can significantly increase the fracture area as well. When conducting fracturing in clayey silt hydrate-bearing sediments, the fracturing fluid filtration area is obviously larger than the fracture propagation area. Therefore, it is recommended to use a high-viscosity fracturing fluid to reduce the filtration of the fracturing fluid and improve the fracturing fluid efficiency. This study preliminarily explores the feasibility of temporary plugging fracturing in clayey silt hydrate reservoirs and analyzes the effect of completion methods on the propagation of fracturing fractures, which can provide a reference for the research conducted on the fracturing stimulation of clayey silt hydrate reservoirs. [ABSTRACT FROM AUTHOR]

We develop silting theory of a Noetherian algebra |$\Lambda $| over a commutative Noetherian ring |$R$|⁠. We study mutation theory of |$2$| -term silting complexes of |$\Lambda $|⁠ , and as a consequence, we see that mutation exists. As in the case of finite-dimensional algebras, functorially finite torsion classes of |$\Lambda $| bijectively correspond to silting |$\Lambda $| -modules, if |$R$| is complete local. We show a reduction theorem of |$2$| -term silting complexes of |$\Lambda $|⁠ , and by using this theorem, we study torsion classes of the module category of |$\Lambda $|⁠. When |$R$| has Krull dimension one, we describe the set of torsion classes of |$\Lambda $| explicitly by using the set of torsion classes of finite-dimensional algebras. [ABSTRACT FROM AUTHOR]

Compared with conventional soft clay ground treatment methods, electroosmosis has many advantages, such as a fast drainage rate and convenient equipment installation. However, its practical applications encounter restrictive factors, such as severe electrode corrosion and high energy consumption. As a flexible electric geotextile, carbon fiber cloth has good electrical conductivity and durability and excellent electrical contact performance with the soil. In this paper, carbon fiber cloth was used as the electrode material, and electroosmosis combined with the chemical grouting method was used in laboratory model tests. The electroosmotic characteristics and electrode-soil interface characteristics of carbon fiber cloth electrodes were discussed, and the influence of chemical grouting on these characteristics was considered. The results indicate that injection of CaCl2 and Na2SiO3 solution reduced the soil resistance and electrode-soil contact resistance but reduced the electroosmotic drainage rate and increased the energy consumption coefficient. The electrode-soil contact resistance of the carbon fiber cloth electrode was less than that of the stainless steel electrode and had a higher efficiency of electric energy utilization when injected with chemical solution. [ABSTRACT FROM AUTHOR]

The cornerstone assumption of all Flood Geology models is that rocks can form quickly (i.e., within the timeframe of months to years). However, to date, only isolated examples from the field have been used to support the hypothesis without any quantitative justification. This paper therefore presents the theoretical basis (originally set out by Terzaghi, 1922) for determining the timescales for the first phase of lithification, the mechanical compaction of the sediment under its self-weight (otherwise known as consolidation). The paper demonstrates that when basic soil mechanics theory is applied to the consolidation of thick clay layers of the order of 1,000 m such as those found in the North Sea, Gulf of Mexico, and the Caspian Sea, the timescales predicted for compaction are orders of magnitude greater than is currently assumed. Additionally, it is shown that there is a physical limit to the rate at which sediment can accumulate without creating excessive pore pressure and inducing geotechnical failures. For clay, this limit is approximately 0.1 m/yr, and, for silt, approximately 10 m/yr. [ABSTRACT FROM AUTHOR]

Characterizing the influence factors of exhaust gas based on the suspended road dust on paved roads, according to the number of vehicles and their distance with regard to driving pattern, is important in order to provide a coefficient for driving patterns to find a model equation. This has been a limitation of previous studies, in which this was difficult to carry out in a large area reflecting various driving patterns because some sections were selected according to empirical measurement results, and only one vehicle measurement was used to find the level of road dust. This study measured the concentration of suspended road dust that could occur, depending on the vehicle's driving patterns, on an experimental road in Yongin, South Korea, from May to July 2023. The study was conducted to determine the degree of the effect of exhaust gas, according to the concentration of suspended road dust generated, by determining the separation distance based on real-time measurements. This study attempted to determine the changes in suspended road dust based on driving patterns in urban areas and factor in the concentration of suspended road dust with regard to emission characteristics in terms of exhaust gas and particulate matter with a diameter of 10 microns or less (PM10). This was in accordance with conditions evaluated using mobile laboratories, based on suspended-PM10-concentration-measuring equipment. This study mainly focused on the following main topics: (1) increasing the level of suspended particulate matter at less than 10 m intervals produced by exhaust gas; (2) decreasing the level of suspended road dust with an increase in the number of vehicles, with the area measured at a distance of three cars in front showing the lowest level of suspended road dust in the air and a low level for the rear vehicle; (3) demonstrating that PM10 is effective in measuring the generation of suspended road dust; and (4) evaluating suspended road dust levels by road section. Based on the results, this research is necessary to more appropriately set the focus of analyses that aim to characterize suspended road dust according to exhaust gas and PM10 content in silt. [ABSTRACT FROM AUTHOR]

To investigate the potential use of Red mud (RM) and desulfurization gypsum (DG) in dealing with roadbed filling, a series of laboratory tests, such as compaction tests, unconfined compressive strength (USC) tests, water stability tests, basic physical-chemical properties tests and microscopic tests were conducted on the abandoned silt (AS) from Foshan, Guangdong. The results indicates that the strength and water stability of cement-treated AS increase with the addition of RM and DG. The UCS of specimens with the addition of 3% RM and 2% DG increases by 23.33% than that of pure OPC after 60 days of curing. Meanwhile, the water stability coefficient of DG-RM-OPC treated AS is increased by 0.41% to 14.42% compared to OPC treated AS, especially for C5RM6DG4, whose water stability coefficient is increased by 14.42%. The main reason can be attributed to the collaborative effects between RM and DG, under which the SiO2- 4 provided by DG reacts with the Al3+ provided by RM to promote the formation of AFt. The research results show promising application of RM and DG in cement-treated AS, and provide a reference for the utilization of AS, RM and DG. [ABSTRACT FROM AUTHOR]

Macroscopic soil‒water characteristic tests and microscopic nuclear magnetic resonance (NMR) tests on compacted silt in the yellow river flooding area under four stress states were conducted to study the impact of stress changes on the soil‒water characteristics and microscopic pores of silt, and to clarify the microscopic mechanism of the influence of the stress state on the soil‒water characteristics of silt. The results were as follows. With the increase of normal stress, the water-holding capacity of silt enhances, the hysteretic characteristics weaken, and the air-entry value of the soil‒water characteristic curve increases. In addition, the boundary effect stage lengthens and the conversion phase moves up, but the slope of the conversion phase does not change significantly. The compacted silt has a bimodal pore structure. With increasing normal stress, the volume of pores between the aggregates decreases, the pore volume within the aggregates increases, and the maximum pore size in the soil decreases. However, the stress does not change the dominant pore size or the pore size distribution range in the aggregates. The changes in pore size distribution between silt aggregates caused by stress are intrinsic to the change in soil‒water characteristics. The results contribute to deepening the understanding of the water-holding characteristics and microscopic features of unsaturated silt in the Yellow River flooding area. [ABSTRACT FROM AUTHOR]

The conventional constitutive models for mairne silts are usually built on different loading surfaces and plastic potential surfaces. In this paper, based on the concept of critical state, combined with the modified Cam-clay model and fractional-order calculus algorithm, the fractional-order elastic-plasticity constitutive model of the marine silt is studied and proposed. The basic characteristics of the model, such as the shear shrinkage, friction and stress history dependence of the marine silt, are comprehensively considered, and the parameters are easy to obtain. The experimental results and predicted results of different initial void ratios under undrained conditions are compared. The results show that the constitutive model can well simulate the strain hardening of the marine silt with different initial void ratios under undrained conditions. The predicted results of the model under different initial confining pressures are not consistent with the experimental results under fixed λ value. By changing λ, the stress-strain relationship of the marine silt can be effectively simulated. At the same time, the maximum deviator stress increases with the increase of the initial confining pressure, and the phenomenon that increases with the decrease of the initial void ratio can be predicted by this model. [ABSTRACT FROM AUTHOR]

We consider a finite dimensional strongly G -graded algebra A with self-injective 1-component B , and in our main result we prove that the induction from B to A of a basic support τ -tilting pair of B -modules is a support τ -tilting pair (M , P) of A -modules if and only if M is G -invariant. A similar statement holds for the restriction from A to B , so our results may be viewed as Clifford and Maschke type theorems for 2-term silting complexes. We also give applications to semibricks and the associated wide subcategories. [ABSTRACT FROM AUTHOR]

In March 1966, Ms 6.8 and 7.2 earthquakes occurred in Xingtai, North China, resulting in widespread soil liquefaction that caused severe infrastructure damage and economic losses. Using Keyhole satellite imagery combined with aerial images and fieldwork records, we interpreted and identified 66,442 liquefaction points and analyzed the coseismic liquefaction distribution characteristics and possible factors that influenced the Xingtai earthquakes. The interpreted coseismic liquefaction was mainly concentrated above the IX-degree zone, accounting for 80% of all liquefaction points. High-density liquefaction zones (point density > 75 pieces/km2) accounted for 22% of the total liquefaction points. Most of the interpreted liquefaction points were located at the region with a peak ground acceleration (PGA) of >0.46 g. The liquefaction area on 22 March was significantly larger than that on 8 March. The region of liquefaction was mainly limited by sandy soil conditions, water system conditions, and seismic geological conditions and distributed in areas with loose fine sand and silt deposits, a high water table (groundwater level increases before both mainshocks corresponding to the liquefaction intensive regions), rivers, and ancient river channels. Liquefaction exhibited a repeating characteristic in the same region. Further understanding of the liquefaction characteristics of Xingtai can provide a reference for the prevention of liquefaction in northern China. [ABSTRACT FROM AUTHOR]

Many regions of Iran lack digital map of soil properties. The Chahardowli plain in western Iran is one of these areas. Due to the importance of sand, silt, and clay components, having quantitative and continuous data on abrupt changes in these two properties in this area is very critical. Therefore, to study sand, silt, and clay, samples were taken at depths of 0-5, 5-15, 15-30, 30-60, and 60-100 cm, according to GlobalSoilMap. Finally, 145 samples were collected from 30 soil profiles. The significant covariates were selected by Random Forest Recursive Feature Elimination (RF-RFE). Relationships between these characteristics and environmental predictors were modeled using random forest (RF), decision tree (DT), and multiple linear regression (MLR) models. The accuracy and precision of the models used for all three particles showed that the RF model had the most accurate prediction with R² and RMSE of 0.82 and 2.34 for clay, 0.80 and 3.87 for sand, and 0.85 and 2.89 for silt, respectively. In this study, terrain-based variables had a greater impact on improving accuracy than remote-sensing variables. The current study showed that even with limited information, digital mapping of sand, silt, and clay particles under GlobalSoilMap and the use of environmental factors can provide acceptable results. [ABSTRACT FROM AUTHOR]

Geochemical indices used to identify the emerging anomalies of potentially harmful elements in topsoil depend on background values (BVs). For urban sites, it is reasonable to estimate native BVs through the targeted selection of peri-urban sampling sites or by distinguishing a useful background subset (BS) within the peri-urban dataset. Here, the goals were to examine the influence of Quaternary deposits on various types of topsoil variables, identify the variables most helpful for cluster analysis intended for the choice of background subset (BS), and compare background values (BVs) based on different background subsets. Composite topsoil samples from a peri-urban area were used for the determination of the following variables: contents of 26 elements and components of the bulk mineralogical composition, as well as the sand, silt, and clay fractions and loss-on-ignition (LOI) at 550 °C and at 950 °C. Although Quaternary lithology influences topsoil elemental contents or granulometric fractions, percentages of illite, kaolinite, orthoclase, quartz, albite, dolomite, and LOI at 550 °C, the choice of BS, according to it, is not recommended, as BVs based on topsoil texture are superior. However, cluster analysis using topsoil fractions < 2, <63, and >63 μm or the contents of Al, Fe, K, Ti, Ga, Nb, Rb, and Si are preferable. It is recommended to use these reference variables for the selection of BS. [ABSTRACT FROM AUTHOR]

The new genus Alena Polechová, Zicha and Rak, with its type species Alena pustulosa nov. gen., nov. sp., is described from the Sandbian Letná Formation of the Prague Basin (Czech Republic) as a new Late Ordovician bivalve with pustules. Alena pustulosa nov. gen., nov. sp. appears to be an endobyssate bivalve based on its functional morphology. It is placed within Cyrtodontida (Pteriomorphia) and included in the diversified Modiolopsis draboviensis Association from the Letná Formation, which comprises eleven bivalve species. The bivalve association from the Letná Formation is formed predominantly by pteriomorphids (now six species out of eleven) and shows that pteriomorphian groups also radiated strongly in shallow-water sands and silts in mid-latitude areas. All main groups of Pteriomorphia are already known from the Early Ordovician and diversified rapidly during the Ordovician. The Gondwana and peri-Gondwana margins with two Early Ordovician radiation centers (Central Australia and Northwestern Argentina) played important roles in their early diversification and dispersion to other palaeocontinents. The function of the sculpture in bivalves is discussed with an emphasis on the Ordovician bivalves. The ornamentation in bivalves serves several purposes such as supporting the stable position of the shell in a substrate, helping in burrowing, strengthening of shell, and protecting against predators. In the Ordovician bivalves, the main function of the sculpture is to stabilise the shell in the substrate. [ABSTRACT FROM AUTHOR]

Zebra Mussels (Dreissena polymorpha) were introduced into the US in the 1980s and have since spread throughout the country with concomitant impacts on aquatic ecosystems. We placed 20 m transects in a variety of sediment types and collected data on sediment size, mussel coverage (the percent of the bottom covered by mussels), and the presence of macrophytes within 0.25 m2 quadrats in White Bear Lake, MN. To assess the degree of Zebra Mussel aggregation, we calculated Morisita's index of dispersion (Iδ) at four levels of spatial scale − 0.25 m2, 1 m2, 4 m2, and 40 m2. Understanding the pattern of aggregation in Zebra Mussels is crucial in detecting early invasions, monitoring populations, and attempting to eradicate them. There was greater Zebra Mussel coverage within quadrats with coarser substrates (gravel/cobble and mixed sediment – including rock and boulders) compared to those with finer substrates (silt and sand). Macrophyte coverage did not significantly influence Zebra Mussel coverage on the lake bed sediments. Spatial scale had a large impact on the measure of mussel aggregation. Zebra Mussels in sand and silt had the highest degree of aggregation and high levels of macrophytes resulted in greater degrees of aggregation on the lake bed sediments. Zebra mussel coverage measured at larger spatial scales generally resulted in lower aggregation values, across both sediment types and levels of macrophyte coverage. The appropriate selection of spatial scale for sampling or observation is critical when upscaling local density to lake populations. Zebra Mussels have spread throughout the US and significantly alter aquatic ecosystems. Zebra mussels are often aggregated on the bottom of aquatic systems and are found preferentially on lake beds with coarser material at the bed (gravel and rock). Using the correct spatial scale to assess mussel coverage is crucial for accurate population estimates. Zebra Mussel infestations might be managed by partial-lake treatment options; however, treatment areas need to be chosen based on Zebra Mussel density and distribution patterns. Knowledge of the relationship between spatial scale, sediment type, macrophyte availability and population coverage and aggregation is needed for these types of treatment programs. [ABSTRACT FROM AUTHOR]

Foundations are subjected to combined vertical-horizontal-moment (V-H-M) loadings during operation, and no investigations have been carried out for multicompartment single-bucket structures under combined loadings. Based on the actual stratum distribution of Xu Wei port in Lianyungang, a series of finite element analyses were performed through the finite element software ABAQUS to explore the influence of silt layer thickness, silt strength non-homogeneity and foundation embedment depth on the structural bearing capacity, and the bearing capacity of the structure under combined loading was systematically analyzed. The results suggested that the uniaxial capacity of the structure showed an evident trend with the above parameters. The normalized failure envelopes were not affected by the silt strength non-homogeneity index and were influenced to some extent by the silt layer thickness for a given embedment depth. The normalized V-H and V-M failure envelopes shrank inward, while the normalized H-M failure envelopes tended from negative eccentricity to positive eccentricity with an increasing embedment depth. On this basis, formulas for predicting the uniaxial capacity and the failure envelopes as a function of the overlying silt layer thickness, silt strength non-homogeneity and embedment depth were proposed to provide a reference for its design. [ABSTRACT FROM AUTHOR]

In this paper, we prove a reduction result on wide subcategories of abelian categories which is similar to the Calabi-Yau reduction, silting reduction and τ -tilting reduction. More precisely, if an abelian category A admits a recollement relative to abelian categories A ′ and A ′ ′ , which is denoted by (A ′ , A , A ′ ′ , i ∗ , i ∗ , i ! , j ! , j ∗ , j ∗) , then the assignment C ↦ j ∗ (C) defines a bijection between wide subcategories in A containing i ∗ (A ′) and wide subcategories in A ′ ′. Moreover, a wide subcategory C of A containing i ∗ (A ′) admits a new recollement relative to A ′ and j ∗ (C) which is induced from the original recollement. [ABSTRACT FROM AUTHOR]

Roller-integrated compaction monitoring technology has been widely used in highway construction and has played an important role in controlling compaction quality and construction progress. In order to detect and assess the compaction quality of the subgrade accurately in real time based on the analysis of the acceleration signal of the vibrating wheel, a total of four real-time monitoring indexes, namely, peak value of acceleration (Ap), compaction meter value (CMV), root-mean square value of acceleration (Arms), and crest factor value (CF), were selected to characterize the compactness of the soil. To determine which of these indexes is the most appropriate, field compaction experiments under various rolling conditions were carried out on the fifth section of the Hengyong Highway in Hunan Province, China. The data of compaction parameters, compaction quality, and integrated compaction monitoring under various working conditions were collected and subjected to statistical regression analysis. On the basis of the time-frequency analysis of vibration response signals, the CMV could more accurately characterize the compactness of low-liquid-limit silt. In addition, the mapping relations between compaction quality index and roller-integrated compaction monitoring indexes were founded to define the control criterion of roller-integrated compaction monitoring index, namely, CMV, providing scientific guidance for making sure the compaction quality of the subgrade during construction. [ABSTRACT FROM AUTHOR]

The engineering properties of cemented silt with rubber fines and rubber buffings mixtures are investigated using compaction, unconfined compression, direct shear, and freeze–thaw (FT) cycle tests. The rubber fines (20-mesh size, 80-mesh size), rubber buffings, and cement content in these specimens are equal to 2.5%, 5%, 7.5%, 10%, 12.5%, 15% and 3%, and 5% of dry weights, respectively. The maximum dry density of the modified soil is significantly reduced after adding the waste tire rubber. Furthermore, the addition of rubber fines is more evident in the decrease of maximum dry density compared with the inclusion of rubber buffings. The addition of rubber fines and rubber buffings improved shear strength, including cohesion and friction angles. The unconfined compressive strength of most specimens decreased after the tire rubber is added. However, cement hydration in the early curing stages is inhibited when rubber is added. As a result, the optimal dosage of the rubber buffings is 5%. The FT cycle tests indicated that the strength of the soil blended with the rubber buffings decreased after FT cycles, and the lowest value is found after the sixth cycle, and the specimen porosity increases with rubber buffings, and this effectively reduced the influence of water frost. In general, the modified soil had good FT resistance. [ABSTRACT FROM AUTHOR]