Different Degrees Of Compaction Research Articles

Drying and calendering of Lithium Ion battery electrodes: A combined simulation approach

In drying of battery electrodes, high drying speeds are desirable but lead to binder segregation resulting in lower adhesion strength and poorer electrochemical performance. During calendering, the elastic recovery of the electrode makes it difficult to estimate the line load required to achieve the desired porosity. The approach we present incorporates various drying and binder migration models and combines them with a calendering model as Sangros used it. The drying models taken from literature put a special focus on drying kinetics, binder segregation and particle dynamics. This information is passed to a solid-state bridge-based Discrete Element Method, which is additionally extended to include the interactions between the coating and the current collector. Through the interaction of these models, the mechanical behavior by means of stress and elastic recovery of model cathodes can be predicted for different degrees of compaction as well as areal loadings.

The effect of different degree of compaction towards electrical resistivity value for cohesive soil

The effect of different degree of compaction towards electrical resistivity value for cohesive soil

Charge Distribution Patterns of IA3 Impact Conformational Expansion and Hydration Diffusivity of the Disordered Ensemble.

IA3 is a 68 amino acid natural peptide/protein inhibitor of yeast aspartic proteinase A (YPRA) that is intrinsically disordered in solution with induced N-terminal helicity when in the protein complex with YPRA. Based on the intrinsically disordered protein (IDP) parameters of fractional net charge (FNC), net charge density per residue (NCPR), and charge patterning (κ), the two domains of IA3 are defined to occupy different domains within conformationally based subclasses of IDPs, thus making IA3 a bimodal domain IDP. Site-directed spin labeling (SDSL) electron paramagnetic resonance (EPR) spectroscopy and low-field Overhauser dynamic nuclear polarization (ODNP) spectroscopy results show that these two domains possess different degrees of compaction and hydration diffusivity behavior. This work suggests that SDSL EPR line shapes, analyzed in terms of their local tumbling volume (VL), provide insights into the compaction of the unstructured IDP ensemble in solution and that protein sequence and net charge distribution patterns within a conformational subclass can impact bound water hydration dynamics, thus possibly offering an alternative thermodynamic property that can encode conformational binding and behavior of IDPs and liquid-liquid phase separations.

Mechanical properties of solidified dredged soils considering the effects of compaction degree and residual moisture content

The use of biopolymers in combination with natural plant fibers to solidify soils has proven effective in civil engineering, as they are not only considered sustainable, but also have excellent mechanical properties. However, the specific quantitative relationships between mechanical strength and residual moisture content (RMC) in the cured system are still unclear. In this study, the solidification effects of xanthan gum (XG, weight ratio to dry soil of 1.5%) and jute fiber (JF, weight ratio to dry soil of 0.6% and length of 20 mm) on the Yellow River dredged soil (YRDS) were investigated at different degrees of compaction (90%, 94% and 98%) after reaching a preset RMC (75%, 50%, 25% and 0%). The results show that unconfined compressive strength (UCS) and splitting tensile strength (STS) increase significantly with decreasing RMC and increasing compaction. The effect of internal moisture on STS was even more dramatic, with a maximum increase of 404% especially when the RMC was reduced from 25% to 0%. The contribution rate of strength (Rcsi) of UCS reaches 49.09%–51.85%, while the Rcsi values of STS at the same RMC of 25% reach only 19.86%–23.08%. A logistic function based model can predict well the mechanical strength at different RMC (R2 ≥ 0.9789). MIP and SEM results show that increasing the degree of compaction mainly affects the large pores (20–100 μm) and improves the mechanical strength by enhancing the bonding effect between XG and JF in the soil particles. In addition, 94% compaction ratio is an optimal choice for practical engineering applications.

Inclusión de técnicas de sísmica de refracción en la definición del entorno geológico con fines de aprovechamiento geotérmico

Given the growing importance of geothermal energy in the decarbonization of the energy sector, the application of appropriate methodologies that contribute to a greater knowledge of the resource is considered convenient. In this sense, refraction seismic techniques have proven to be a potential tool to predict the thermal behavior of the subsoil in locations where it is intended to implement a shallow geothermal system. From thermal conductivity measurements on samples with different degrees of compaction and consolidation, and from the propagation speeds of the P waves, a correlation pattern is developed that in turn allows obtaining 2D sections of the average thermal conductivity distribution in depth. The methodology developed shows that it is possible to estimate the evolution of the thermal conductivity parameter of the ground and thus guarantee an adequate design of the well field and the future correct operation of the geothermal system (providing the correct drilling length which would be underestimated by 30% with the standard thermal conductivity values).

Correlation of Electrical Resistivity Tomography and Geotechnical Field Data for Soil Profile Characterization

This study looked at the effects of compaction on resistivity values as well as the relationship between different degrees of compaction. The material used in this experiment was laterite soil. The sample was tested into a standard proctor mould. The model has 10.20cm diameter and 11.6 cm for height of the mould. Each sample's resistivity was measured entirely compacted.The resistivity testing in this study were conducted using the Miller 400A. ASTM D 422 Standards were used, and for electrical resistivity testing, ASTM G57 is used. This research emphasises the impact of moisture content on resistivity value, as soil reduces resistivity value when the soil has higher moisture content which is 120 Ωm at 37%, and 190 Ωm at 25%. By comparing the results of different moisture content of soil samples under varied degrees of compaction, better resistivity interpretation tables may be generated.

Experimental Investigation on Shear Behavior of Partially Saturated Silty Soil under Constant Water Content and Constant Void Ratio Conditions

Abstract Matric suction is a crucial parameter that affects how unsaturated soils behave in terms of shear strength. Understanding it is essential for solving geotechnical problems like the stability of unsaturated soil slopes, foundations, embankments, and retaining walls. To investigate the shear behavior in unsaturated soil, a double cell triaxial test apparatus is used in the current research to carry out a series of triaxial compression tests under constant water content and constant void ratio conditions. Samples of silty soil, named DL-clay, were prepared with three different degrees of compaction: 80 %, 83 %, and 86 %, and water contents of 20 % (optimum water content) and 25 %. The soil samples were consolidated isotropically under net confining pressures of 300 kPa and 500 kPa before being sheared with constant volume. In another series of tests, water was infiltrated into the sample at 0 kPa deviatoric stress before the start of shearing with constant volume. Some specimens were also sheared with constant confining pressure for comparison purposes. From the test results, it is ascertained that maintaining a constant volume, i.e., constant void ratio during shearing, gives contour-like trajectories that can aid in defining the state boundary surface of unsaturated soil. It was also observed that within the axial strain range of 0–2 %, there was unusual behavior of a temporary sudden dip in the axial stress, which was more perceivable for samples having a high value of initial matric suction.

Lunar active seismic profiler for investigating shallow substrates of the Moon and other extraterrestrial environments

To investigate the structures and properties of shallow material in extraterrestrial environments, we have developed a lunar active seismic profiler (LASP), which integrates active seismic sources and receivers in a short (~1 m) array that can be deployed on a rover. The small active source generates a chirp waveform that sweeps over a wide frequency range (20–250 Hz). The receivers are coupled to the ground by their own weight, but nevertheless deliver acceptable performance. We improve the signal-to-noise ratio of the seismic signal by stacking waveforms, enabling a minimal source to support the exploration of geological substrates. By processing shot gather of the LASP data, we calculated a dispersion curve of surface waves and obtained an accurate S-wave velocity profile from surface to 1 m depth. The results suggest that regions with even small amounts of subsurface ice (~0.5 wt%) can be identified in LASP results by their anomalously high S-wave velocity. Field experiments demonstrate that the LASP can support estimates of 3D S-wave velocity distributions and the identification of a buried geological boundary. The LASP also detected different degrees of compaction at the experimental site. If two rovers carry these profilers, or if a single rover combines one with a separately deployed receiver or active seismic source, seismic refraction and seismic reflection analyses can be conducted simultaneously in addition to surface wave analyses. These seismic surveys for longer-offset data achieve the exploration of deeper substrates in extraterrestrial settings such as the Moon, Mars, and other solid bodies.

Indoor Experiments on the Moisture Dynamic Response to Wind Velocity for Fuelbeds with Different Degrees of Compactness

The semiphysical method is presently the most widely used for predicting litter moisture content, but it produces some errors. These are mainly due to the simplification of the water loss process and not accounting for the fuelbed structure, which can have a serious impact on the accuracy of litter moisture content predictions and, consequently, on forest fire management. As such, in this study, we constructed fuelbeds with different degrees of compactness, and the moisture content is saturated at this time. The drying process is recorded every 10 min under different wind velocity, and the experiment is stopped when the moisture content is not changing. Taking the saturated fibers’ moisture content (30%) as the threshold value, the drying process was artificially divided into two stages (from the initial moisture content to 30%, it is a process of free water drying, and from 30% to the equilibrium moisture content, this is the process of drying of bound water), which is called the distinguishing drying process. The whole drying process (from the initial to the equilibrium moisture content) is called the undistinguishing drying process. Drying coefficient and effect factors were calculated by distinguishing and not distinguishing the drying process, respectively. This established a prediction model based on compactness and wind velocity. The results show that the drying coefficients, k2 and k, of the two litter types were significantly different: the k2 of the white oak fuelbed was significantly lower than its k, with a maximum variation difference of 57.10%. The k2 in the Masson pine fuelbed was significantly higher than its k, with a maximum variation difference of 72.76%. Wind velocity and compactness had significant effects on all the drying coefficients of the two litter types, but with changes in the effect factors. The changes in k2 were weaker than those of the other drying coefficients. Compared with the model that did not distinguish the drying process, the MRE of the prediction models for white oak and Masson pine decreased by 27.39% and 2.35%, respectively. The prediction accuracy of the model of the drying coefficient obtained by distinguishing the drying loss process was higher than that of the model that did not distinguish the drying process. This study was an indoor simulation experiment that elucidated the drying mechanism of litter and established a prediction model for the drying coefficient based on effect factors. It is of great significance for further field verification and for improving the accuracy of moisture content predictions based on the semiphysical method and will significantly improve the accuracy of fire risk and fire behavior prediction.

Effect of Aggregate Size and Compaction on the Strength and Hydraulic Properties of Pervious Concrete

Pervious concrete is one of the emerging sustainable materials that has recently gained the attention of many researchers. The importance of pervious concrete mainly depends on its application and on a modern integrated approach in which it is employed to reduce the effects of flooding. The main goal of this experimental analysis is to study the significance of aggregate size and the degree of compaction on the mechanical and hydraulic properties of pervious concrete. Eleven concrete mixture proportions were investigated by controlling the constituents with different aggregate fractions. The important variables considered were the aggregate sizes, viz., 0/4 mm, 4/8 mm, and 8/16 mm, with four different degrees of compaction. The porosity of the concrete structure was obtained by the partial filling of the voids in the aggregates with cement paste. The ingredients of the pervious concrete were also varied to study their significance and to evaluate the predominant factor that controls the mechanical and hydraulic properties based on the test results. Tests were conducted to determine properties such as compacting factor, compressive strength, splitting tensile strength, abrasion resistance, porosity, and hydraulic conductivity. The study revealed that the degree of compaction was one of the critical factors governing the strength and hydraulic properties of the pervious concrete; the maximum strength and minimum hydraulic conductivity were achieved with a higher degree of compaction. The test results imply that the cement content is the predominant factor determining the fresh and tensile properties of the pervious concrete, rather than the size of the aggregates used. In addition, the results also illustrated that the highly compacted pervious concrete samples made with 4/8 mm aggregates exhibited improved abrasion resistance and strength properties, but slightly reduced hydraulic conductivity, despite the designed porosity.

The Effect of Compaction Towards Resistivity Value

Electrical resistivity tomography is a non-destructive method of site investigation that involvesinjecting electricity into the sample and measuring subsurface resistance. This study looked at the effects of compaction on resistivity values as well as the relationship between different degrees of compaction. The material used in this experiment was laterite soil. The sample was tested into a standard proctor mould. The model has 10.20cm diameter and 11.6 cm for height of the mould. Each sample's resistivity was measured entirely compacted.The resistivity testing in this study were conducted using the Miller 400A. ASTM D 422 Standards were used, and for electrical resistivity testing, ASTM G57 is used. This research emphasises the impact of moisture content on resistivity value, as soil reduces resistivity value when the soil has higher moisture content which is 120 Ωm at 37%, and 190 Ωm at 25%. By comparing the results of different moisture content of soil samples under varied degrees of compaction, better resistivity interpretation tables may be generated.

Hydrostatic pressure in granular environment

The problem is that to date there is no general theory of the granular state of matter in a closed form. However, there are some well-developed models that use, for example, the representation of a continuous environment. Typical bulk material is a large conglomeration of micro-mechanical particles of different sizes and shapes that interact with each other and the walls contain containers by mainly repulsive forces in direct mechanical contact (by nature it is forces of electromagnetic origin – dry and viscous friction forces, as well as traction).In the proposed work to study the pressure in a multiparticle micro-mechanical system, a model of a lattice gas in a gravitational field is considered. Analysis of the determination of free energy and entropy allowed us to establish the corresponding equilibrium density profile, which is described by a Fermi-type function. The Fermi profile in the form of a density field was used to find the vertical hydrostatic pressure for which the analytical expression was obtained. Hydrostatic pressure was different from the known relations derived from the theory of condensed matter. The obtained results are confirmed by experimental observations, which indicate a complex, anisotropic significantly different from the known from the theory of condensed matter distribution of even vertical pressure in large conglomerations of discrete micro-mechanical particles. Which really repeats the Fermi distribution. The obtained results stimulate the revision of typical ratios of hydrostatics of continuous media, such as Pascal's laws. Torricelli, Archimedes and Bernoulli in the case of discrete micro-mechanical (granular) systems. The conclusions of the work can be significant in the design and evaluation of operating parameters of storage, release and transportation of bulk cargo, which consist of discrete micro-mechanical conglomerations with different degrees of compaction and compaction.

Macromolecular Crowding and Intrinsically Disordered Proteins: A Polymer Physics Perspective

AbstractThe cell is a crowded environment where a relevant fraction of the available space is occupied by proteins, nucleic acids, and metabolites. Here we discuss recent advancements in the understanding of crowding effects on intrinsically disordered proteins. Differently from their structured counterparts, these proteins do not adopt a stable three‐dimensional structure and remain flexible and dynamic in solution. The physics of polymers and colloids provides a framework to interpret how crowding modulates conformations, dynamics, and interactions of disordered proteins. Flory‐Huggins models enable rationalizing the different degree of compaction induced by crowding agents in terms of depletion interactions. The same interactions modulate the diffusion of the disordered proteins in a crowded milieu and the association and dissociation rates when interacting with a ligand. Altogether, this theoretical framework provides new insights into the interpretation of the effects of the cellular environment on disordered proteins.

Effects of Freeze–Thaw Cycles on Volume Change Behavior and Mechanical Properties of Expansive Clay with Different Degrees of Compaction

Freeze–thaw (F-T) cycles are one of the main deterioration factors for the performance of expansive clay in seasonally frozen soil regions. This study designed a unidirectional environmental boundary loading device for F-T cycle tests. Laboratory tests were conducted to quantitatively evaluate the effects of the F-T cycle on volume change behavior and mechanical properties of expansive clay with different degrees of compaction below the canal in Xinjiang. The SEM image processing was performed with the Image-Pro Plus image processing software to get pore parameters. The results showed that during the F-T cycle, the volume change of the sample gradually changes from contraction to expansion as the degree of compaction increases. As the degree of compaction increases, the hardening characteristics of the expansive clay are weakened, and the F-T cycle promotes the softening of the stress–strain relationship. The first F-T cycle resulted in a significant decrease of failure strength, and the failure strength of different compaction degrees decreased by 56.07%–67.54% after seven cycles. The failure strain and resilient modulus of the samples are attenuated to varying degrees after F-T cycles. The correlation rate between the porosity and the attenuation rate of the failure strength is 0.719–0.882, the corresponding weight reaches 0.419–0.445, and there is an excellent linear relationship between them. The research offers some important insights into the construction and maintenance of expansive clay engineering such as the Xinjiang Canal.

Genetic diversity for agromorphological traits, phytochemical profile, and antioxidant activity in Moroccan sorghum ecotypes

Sorghum, the fifth most important cereal crop, is a well-adapted cereal to arid/semi-arid regions. Sorghum is known for multiple end-uses as food, feed, fuel, forage, and as source of bioactive compounds that could be used for medical applications. Although the great improvement in the process of sorghum breeding, the average yield of this crop is still very low. Therefore, exploring the genetic diversity in sorghum accessions is a critical step for improving this crop. The main objective of the current work was to study the genetic variation existing in a Moroccan sorghum collection. Indeed, 10 sorghum ecotypes were characterized based on agromorphological descriptors. Both quantitative (25) and qualitative (7) traits revealed variability (p < 0.05) among the studied ecotypes. At the seedling stage, most of the ecotypes showed good to high vigor (70%). However, as the sorghum plants grow, the difference between genotypes become more apparent, especially at the generative phase. For instance, three different panicle shapes have been observed, erect (50%), semi-bent (30%), and bent (20%) with different degree of compactness (20% for loose, semi-compact, and compact panicles, and 30% for semi-loose panicles). In another part of this study, the phytochemical composition and antioxidant activities of the sorghum ecotypes have been determined. The results showed variable total phenolic contents, and total flavonoid contents ranging from 125.86 ± 1.36 to 314.91 ± 3.60 mg GAE/g dw and 114.0 ± 13.2 to 138.5 ± 10.8 (mg catechin equivalent/100 g, dw) respectively, with a differential antioxidant activities as well. These results indicate that for any crop breeding program, it is preferable to take into consideration both morphological and biochemical traits for a better selection of high yielding varieties with high added value compounds. Therefore, the implication of these results in the context of sorghum breeding activities could be a resourceful option for farmers.

Study of the Electrical Conductivity of Ion-Exchange Resins and Membranes in Equilibrium Solutions of Inorganic Electrolytes.

The study of the electrical conductivity of ion-exchange membranes in equilibrium electrolyte solutions is of great importance for the theory of membrane processes, in particular for practical electrodialysis. The purpose of the work is to determine the electrical conductivity of industrial ion-exchange membranes MK-40 and MA-40, as well as their basis—granules of a bulk layer of industrial ion exchangers KU-2-8 and EDE-10p, by differential and modified contact methods in electrolyte solutions and the development of a new methodology that will give the values that are closest to the true ones; determination of the dependence of electrical membrane conductivity depending on the type of counterion and concentration equilibrium solution and granules of a bulk layer of ion exchangers on the volume fraction of a dry ion exchanger with different degrees of compaction. It is shown that the dependence of the electrical conductivity of diaphragms on the electrolyte concentration, according to theoretical ideas, disappears under compression. It has been experimentally established that the difference method gives lower values of electrical conductivity in the region of low concentrations. The data obtained by the contact method are in good agreement with the results obtained for compressed diaphragms. The membrane conductivity decreases with increasing ion size.

Spatial Breach Analysis due to Overtopping Flow Depending on the Degree of Compaction for Noncohesive Embankments

This study aimed to an experiment to analyze the spatial levee breach mechanisms due to overtopping according to the degree of compaction. A levee experiment was performed using four different degree of compaction implemented by adjusting the levee compaction thickness and number of compactions, and the effects of the degree of compaction on levee breaching were observed. Under the low degree of compaction, the scale of the levee breach over time was relatively large, and the breach discharge was also significant. This study also observed the change in velocity of the levee crest area through Large Scale Particle Image Velocimetry (LSPIV) analysis of the velocity field at each levee breach stage; in particular, the location where the maximum velocity occurred in the crest area differed according to the degree of compaction. The relationship between the degree of compaction and peak breach discharge shown in experimental results suggests the degree of compaction can directly affect the breach of the levee and the flooding velocity at the low-land area. The clear correlations between the degree of compaction and breach discharge and breach size over time presented in this study can provide detailed information for the design standards and maintenance of the levee.

Water leaching of herbaceous biomass bales to reduce sintering and corrosion

Two different leaching treatments (immersion and irrigation) were applied to the biomass bales of two different herbaceous solid biofuels (barley straw and tall wheatgrass) in order to improve their sintering and corrosion behaviour during combustion. Six immersion treatments (1 h with and without stirring, and 5 h, 1 day and 2 days without stirring) and two irrigation treatments with tap water (900 L and 1800 L) were tested. The bales made of barley straw were of high-density 140 kg/m3) whereas the density of tall wheatgrass bales was lower (80 kg/m3). After the leaching treatment, bales were dried naturally indoors. Sintering and corrosion tests along with chemical elemental analyses, X-ray diffraction and SEM analyses were performed on the lixiviated biomass.An immersion treatment of 5 h reduced the sintering and corrosion potential of both types of bales to an acceptable level. In high-density bales, the irrigation treatment (1800 L) provided similar sintering and corrosion reductions than those obtained when the 5 h immersion treatment was applied. However, in low-density bales, the immersion treatments provided much better results than irrigation leaching systems, probably in connection with their different degrees of compaction. The naturally drying process of the lixiviated bales can be considerably long, particularly after immersing high-density bales. The drying period to reach a moisture level of 20% w.b, was longer than 100 days for high-density bales and shorter than 20 days for low-density bales.

Effect of initial water content and shear stress on immersion-induced creep deformation and strength characteristics of gravelly mudstone

Soft sedimentary rocks undergo deterioration due to weathering induced by dry–wet cycles in a process known as slaking. To investigate the effect of the initial water content and shear stress on the immersion-induced creep deformation and strength characteristics of gravelly mudstone (slaking index = 1 and 2), creep tests were conducted using a modified direct-shear-test apparatus under different creep-stress ratios. Crushed mudstone with different degrees of compaction and initial water content was subjected to immersion under the creep-shear-stress conditions. After the creep shear and vertical displacements stabilized, a monotonic shear loading was applied. During creep immersion, the increment in the creep-shear displacement increases as the creep-stress ratio increases and the initial water content and/or degree of compaction decrease. Retaining a high initial water content in crushed mudstone is recommended to maintain its shear-stress stability. Under the same density, the peak shear strength decreased with an increase in the increment of the creep-shear displacement during creep immersion. The results indicate that the occurrence of immersion-induced creep deformation in addition to slaking can result in the deterioration of slope stability.

Reinforcing effect of recycled polypropylene fibers on a clayey lateritic soil in different compaction degrees

The present research investigates the reinforcing effect of recycled polypropylene (R-PP) fibers on a compacted clayey lateritic soil in different compaction degrees. R-PP fibers of 12 mm length were mixed with the soil in the contents of 0.1 and 0.25% of soil dry weight. Unconfined compression strength tests (UCS), direct shear tests and indirect tensile strength (ITS) tests were conducted. Fibers addition showed no significate alterations in the optimum compaction parameters. The study evidenced increases in UCS, changing the soil behavior from a brittle failure to a ductile failure, while fiber contribution was most effective for 0.25% R-PP fibers content and 95% compaction degree. The use of fibers improved the shear stress-strain behavior of the composites and soils compacted at different degrees of compaction showed similar shear behavior, which is coherent to the soil water retention curves (SWRC) results. Significant increases in the tensile behavior of soil-mixtures for both fiber contents used were observed, and fibers increase was more significate than increase in soil degree of compaction. The stretching of the fibers and fibers orientation at the sheared interface in direct shear tests and the fiber “bridge” effect in ITS tests could be observed.