Variations In Physical Properties Research Articles

Compaction and clay content control mudrock porosity

Mudrocks, ubiquitous yet poorly understood sedimentary rocks with significant variations in composition and physical properties, form seals for geological carbon dioxide and energy (e.g., hydrogen and methane) storage, repositories for radioactive waste disposal, and reservoirs for natural gas. Understanding the controls on mudrock pore structure is essential for evaluating their porosity. The identification and quantification of controls depend on the nano-to micron scale pore network, which are the subject of this study. Small-angle (SANS) and very small-angle neutron scattering (VSANS) experiments were conducted on 13 diverse mudrock sets, characterised by differences in mineralogy, stratigraphy, maturity, and depositional environment. We performed multivariate statistics to systematically characterise the pore structure in 71 samples cross a 5 μm–2 nm pore size range. Our results indicate a multivariate approach more effectively captures the complex controls on porosity rather than single parameters. Compaction and clay content emerge as key primary and secondary controls on mudrock porosity, respectively, upon which we introduce a new porosity classification. Our complementary experimental-statistical assessment involving SANS-derived multiscale porosity sheds new light on the influence of structural controls on storage or production capacity in mudrocks.

Variation in the physical properties of soil in relation to natural and anthropogenic factors in the hilly loess region of China

Soil particle size distribution (PSD), bulk density (BD), saturated hydraulic conductivity (Ks), soil water content (SWC) and generalized soil structure index (GSSI) are key physical properties for vegetation growth and are easily affected by natural and anthropogenic factors. However, how these soil physical properties respond to land use, slope aspect, slope position, and their interactions are less clearly understood. Here, an experiment with three land uses (cropland, grassland, and black locust [Robinia pseudoacacia L.] forests after 4, 9, 15, and 19 years of restoration), two slope aspects (south and north slope) and two slope positions (up and down slope) were conducted in the hilly loess region of China. The results showed the following: (1) The variation in different physical properties were driven by different factors of land use, slope aspect, slope position and their interactions. (2) The 9, 15 and 19 year old locust forests significantly decreased the BD by 6.75 %–19.32 % and increased the Ks by 69.96 %–195.97 % compared with grassland, while the cropland had higher SWC and GSSI values than the grassland and locust forests. (3) Soil physical properties were higher on the north slope than on the south slope and were larger on the down slope than on the up slope. (4) The BD, Ks, SWC, and GSSI of locust forests displayed different changes with the restoration year. (5) The key factor affecting forest growth and soil quality improvement varied with forest ages. Overall, 19 year old locust was the most effective at improving the BD and Ks. Furthermore, slope aspect, slope position and restoration time should be considered when evaluating the response of physical properties to land uses.

Thermal analysis of AA7075-AA7072/methanol via Williamson hybrid nanofluid model past thin needle: Effects of Lorentz force and irregular heat rise/fall

Hybrid nanofluids have received remarkable attention due their promising thermal performance compared to conventional nanofluids. The use of hybrid nanofluids is widely found in the pumping power, solar collector, electronic components, coolants in nano devices, and engine applications etc. Such types of applications grabbed the attentionof researchers and scientistswith the aim to understand in depththe problems involving the hybrid nanofluids. Therefore, the primary objective of the present investigationis to investigatethe thermal performance of hybrid nanofluid consisting of asuspension of aluminum alloys (AA7075-AA7072) in methanol-base fluid. The non-Newtonian Williamson fluid flow model under Lorentz force, and irregular heat rise/fall impact past incessantly moving thinneedleis considered. The governingflow equations are solved by bvp4c solver. Results are computed for governing flow parameters such as magnetic field parameter, needle thickness parameter, Weissenberg number, volume fractions, and irregular heat rise/fall constants. Graphs confirm that augmenting values of magnetic field parameter, needle thickness parameter, and Weissenberg number lead to downfall of velocity field but reverse behavior is noticed for increasing nanoparticles volume fraction. A rise in temperature field has been noticed by increasing the magnitude of magnetic field, irregular heat rise/fallparameter, and nanoparticles volume fraction but a decline in fluid temperature occurswithraising theneedle thickness parameter. Detailed discussion about the observed variation in physical properties under pertinent parameters effects is presented. The proposed model is validated by comparison with previouslypublished results.

Effects of biochar on the compressibility of soil with high water content

This study investigates the potential utilization of biochar in reclamation fills to improve the compressibility of soil with high water content. Biochar, a recycled carbon-rich biomass commonly used for contaminated soil remediation and carbon sequestration, is examined for its impact on the compression behavior of treated soils. The influence of biochar content, initial water content (w0), and biochar saturation on the compression behavior of biochar-treated soils with high water content is analyzed. The results revealed that the addition of both raw biochar and biochar saturated with water significantly enhances the remolded yield stress (σ′yr) and reduced the void ratio (eyr) at σ′yr. Raw biochar exhibits higher σ′yr and lower eyr values compared to water-saturated biochar, mainly due to its greater water absorbing potential of raw biochar. The variations of σ′yr and eyr induced by biochar can be attributed to the decrease in initial void ratio (e0) and the increase in void ratio at liquid limit (eL), which can be effectively normalized using empirical equation developed for reconstituted soil without biochar. Furthermore, the compression parameters (e*100 and C*c) show a decreasing trend with increasing biochar content and decreasing initial water content. Soil with saturated biochar displays higher e*100 and C*c values in comparison with soil with raw biochar. The changes in e*100 and C*c corresponded well to empirical equations developed for reconstituted soil without biochar, indicating that the compressibility changes induced by biochar depended on variations in physical properties (e0 and eL), following similar patterns observed in reconstituted soils without biochar. Therefore, the compression curve of biochar-treated soil in the postyield regime can be effectively normalized by using void index into the ICL or EICL, suggesting its practical applicability for predicting the compressibility of reclamation soil with biochar. These findings demonstrate that biochar-treated soil with high water content exhibits favorable geotechnical properties, making it suitable for use as soil reclamation fills or in landfill applications.

Study of the Integration of Physical Methods in Neural Network Solution of the Inverse Problem of Exploration Geophysics with Variable Physical Properties of the Medium

Study of the Integration of Physical Methods in Neural Network Solution of the Inverse Problem of Exploration Geophysics with Variable Physical Properties of the Medium

Direct numerical simulation of supercritical CO2 near the critical point flowing over a single Stefan flow-affected spherical particle

scCO2 (supercritical CO2) is now an efficient, clean, and pollution-free solvent widely used in industrial productions, such as extraction, printing and dyeing, as well as pharmaceutical productions. In general, a radial mass flux will exist on the surface of active component particles or drug particles during the process of particle dissolution or re-forms due to variations in operating condition of scCO2, which is called Stefan flow. Comparing with the conventional fluids (0.744 < Pr(Prandtl number) < 1.5), typical high-Pr characteristic (Pr > 10) of scCO2 near critical point will present a unique heat transfer performance, while the relative variations of density and viscosity near critical point affect the mechanics characteristic of particle and distribution details of flow field near particle surface, especially considering the effect of different intensities and directions of Stefan flow. To this, based on the PR-DNS (Particle Resolve-Direct Numerical Simulation) method, this work investigates the Stefan flow-affected drag of the sphere, the flow and temperature field near sphere surface, as well as the interphase heat transfer on the sphere surface. We pay more attention to the high-Pr characteristic and relative variations of density and viscosity of scCO2 near critical point. Results point out that the correlation of Nu (Nusselt number) vs. Resf (Stefan Reynolds number) is no longer linear compared with the cases of conventional fluids, and variable physical properties lead larger drag coefficient while worse heat transfer performance.

A simple rheological method for the experimental assessment of the fiber percolation threshold in short fiber biocomposites

The identification of the percolation threshold (Φc) in short fiber composites is a challenging problem in Composite Science. Above Φc the fibers form a continuous network that causes substantial changes in mechanical and transport properties. Besides, percolation of natural fibers in biodegradable polymer matrices allows water and other pro-degradative species to access the inner parts of the material from the external environment, accelerating biodegradation. Whether such a speeding up is desired or not, assessing Φc in composites is of utmost importance. Unfortunately, natural fibers are not conductive and exhibit highly variable shape and physical properties. This prevents the use of many experimental and theoretical approaches for the estimate of Φc. Here we propose an original rheological approach borrowed from the viscoelastic modelling of polymer nanocomposites. The method was applied to two systems made of poly(lactic acid) filled with hemp or kenaf fibers (average length <500 μm, average length-to-diameter ratio <5). The estimate of Φc (∼10.1 and 19.5 vol% for the hemp- and kenaf-based composite, respectively) required a single set of simple linear viscoelastic measurements, and the computed values were in good agreement with those obtained through time-consuming (measurement times >3 weeks) dielectric spectroscopy analyses (∼10.1 and 18.5 vol%).

Assessment of Bödewadt flow over a stretchable porous surface with variable physical properties: A comparative study

Rotating flows occurring over stationary or revolving boundaries have widespread applications in engineering related processes including electrochemistry, turbomachinery (because it involves turbines), compressors and centrifugal pumps, rheometers etc. and in food and chemical processing industries. Bödewadt flow situation concerns a laminar three-dimensional motion taking place over a planar surface in a viscous fluid which is in a state of rigid body rotation at the far field. Present research applies two distinct viscosity-temperature relations to analyze the Bödewadt flow over a stretching porous surface. . A user friendly and robust computational tool bvp4c of MATLAB is utilized to inspect the behaviors of controlling parameters on the resulting boundary layer formations. Interestingly, results corresponding to the two variable viscosity models in case of water are close to each other. The results indicate that either sufficient wall permeability or sufficient surface stretch rate is necessary to have a meaningful solution for the temperature profile. In the case of variable properties, computational data for the drag exhibited at the disk substantially differs from that found for the case of constant fluid properties.

Оценка точности метода измерения сопротивления сверлению древесины в дендрохронологических исследованиях

One of the promising methods for determining physical and mechanical properties and structure of wood is the method based on the measurement of drilling resistance. Limitations of application of the method of measuring drilling resistance in dendrochronological studies are related to a number of factors that have a significant impact on the accuracy of determining the variation of physical and mechanical properties of wood within annual layers: the depth of drilling, its direction relative to the fibers, and the speed parameters of the drilling process. In order to assess the accuracy of measuring the radial growth of pine wood (Pinus sylvestris L.) with moisture content of 6–8 %, the ResistYX device and standard thin drill bits were used. On the basis of comparative analysis of radial wood growth determined by the optical method and the method of measuring resistance to drilling, it was found that in order to obtain accurate data on growth with a correlation coefficient greater than 0.7, it is recommended to measure no more than 17 annual layers on one sample, which corresponds to an average total width of annual layers of 36.6 mm. The influence of the main reasons for the decrease in the accuracy of radial growth determination by the drilling resistance measurement method was studied: geometrical parameters of the cutting part of a thin drill bit, deviation of the drilling direction from the specified one, impossibility of precise determination of the strictly radial drilling direction, wood flaws, as well as friction of the drill shank when the drilling depth increases. To increase the accuracy of the method of measuring drilling resistance in dendrochronological studies it is proposed to develop a method including the use of a special or newly developed tool for more accurate determination of the core and radial drilling of wood or round timber; to increase the rigidity of the thin drill bit; to provide the required fixation of the thin drill bit during its initial contact with wood and inside the device. Further studies in this direction will be associated with the assessment of measuring accuracy for the radial growth of coniferous wood by the feeding force for drill bit penetration. For citation: Chernov V.Yu., Sharapov E.S., Gaisin I.G. Evaluation of the Accuracy of Wood Drilling Resistance Measurement Method in Dendrochronological Studies. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 135–150. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-135-150

Foaming properties of milk samples collected at various processing stages in a dairy processing factory across two seasons.

A foam layer makes an essential contribution to the quality of cappuccino-style drinks. Poor foaming of milk occurs quite often, however, especially in summer. The reasons for this are still unknown. Although a substantial number of studies on the foaming process of milk have been reported, these studies have been laboratory based and have used laboratory or pilot-scale equipment to simulate the processing conditions of a dairy processing factory. This study collected about 40 different samples across different processing stages in a dairy factory over two seasons (two batches per season) and investigated their composition and physical and foaming properties by mechanical mixing and steam injection. The results showed that milk samples collected in summer had a significantly higher content of fat, free fatty acids, and Ca2+ ions, and larger particle sizes but a markedly lower concentration of protein and solid non-fat, and surface tension than the samples collected in spring. These differences provided spring milk with a higher steam injection foamability than summer milk. However, steam injection foam stability, and mechanical mixing foamability and foam stability were not affected by seasonal factors. Milk samples collected in different batches within a season were almost identical with regard to the properties that were investigated. The variations in composition and physical properties of milk collected between two seasons could be the reasons for their difference in foamability but not for foam stability. Processes such as standardization, homogenization, and pasteurization improved markedlythe foaming properties of milk. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Application of machine learning algorithms to model soil thermal diffusivity

Soil thermal diffusivity (k) is an important thermal property that significantly affects ground energy storage and heat transfer. Direct measurements of soil thermal diffusivity are challenging due to sensor limitations and variable soil physical properties, such as water content, bulk density, mineralogy and texture. Therefore, indirect estimations of k are commonly used. In this study, the abilities of six machine learning (ML) models, including k-nearest neighbours (KNN), multilayer perceptron (MLP), support vector regression (SVR), decision tree (DT), random forest (RF) and gradient boosting decision tree (GBDT), to estimate k values are evaluated based on a compiled database consisting of 999 samples. The ML model performances are evaluated by three model performance indicators (i.e., coefficient of determination-R2, mean absolute error-MAE and root mean square error-RMSE). The GDBT model best estimates soil thermal diffusivity, showing the highest fitness (R2 = 0.99). Model estimation accuracies are determined for varying numbers of available model inputs, and recommended minimum numbers of model inputs needed to accurately estimate thermal diffusivity are tabulated. This study demonstrates the ability of ML models to estimate values of soil thermal diffusivity, and it provides reference information for future thermo-related soil science and soil engineering applications.

Numerical investigation of the influence of temperature and composition on the thermophysical properties of an innovative environmentally friendly glass obtained from mineral coal bottom ash

The purpose of this work is to investigate, through numerical simulation, the influence of temperature and chemical composition on the heat capacity, density, and thermal conductivity of a novel eco-friendly glass from mineral coal bottom ash. The modeling used to represent the system is based on the heat transfer in solids with phase-change. The numerical resolution was performed by the finite element method, and the variation of physical properties with temperature and composition was represented by theoretical and empirical equations introduced in the model. After the model is experimentally validated, the behavior of these properties during cooling process was investigated, pointing out higher ash content levels resulted in higher values of heat capacity, and lower values for density and thermal conductivity. Thus, this study brings contributions in the investigation of physical properties of a novel glass obtained by reuse of mineral coal bottom ash from a thermoelectric plant.

Thermodynamic Insights into Variation in Thermomechanical and Physical Properties of Isotactic Polypropylene: Effect of Shear and Cooling Rates.

In order to elucidate the effect of shear and cooling process on structural, thermomechanical, and physical properties of polymer melt, excess entropy, a thermodynamic quantity is calculated from radial distribution function generated from equilibrated parts of the molecular simulation trajectories. The structural properties are calculated, which includes the density of polypropylene melt, end to end distance, radius of gyration of the polypropylene polymer chain, and monomer-monomer radial distribution function. Non-equilibrium molecular dynamics simulation was employed to investigate the role of the applied shear rate on the properties of polypropylene. Furthermore, a range of cooling rates were employed to cool the melt. Thermomechanical properties, such as Young's modulus, and physical properties, such as glass transition temperature, were determined for different cases. Results showed that slow cooling and high shear substantially improved the Young's modulus and glass transition temperature of the i-PP. Furthermore, a two-body contribution to the excess entropy was used to elucidate the structure-property relationships in the polymer melt as well as the glassy state and the dependence of shear and cooling rate on these properties. We have used the Rosenfeld excess entropy-viscosity relationship to calculate the viscous behavior of the polymer under a steady shear condition.

Zones of Weakness Within the Juan de Fuca Plate Mapped From the Integration of Multiple Geophysical Data and Their Relation to Observed Seismicity

AbstractThis study aims to explain the nonuniform earthquake pattern along the Cascadia Subduction Zone. In particular, we investigate the relationship between the tectonic features of the subducting oceanic Juan de Fuca slab and the onshore seismicity pattern. We have integrated multiple geophysical data sets toward three general objectives. The first study intends to study variations in physical properties along three 2‐dimensional models through regions of different seismicities that combine public gravity, magnetic, and seismic data sets. These models reveal multiple zones of decreased crustal density that we interpret as regions of weaker oceanic crust. The second objective is to delineate major tectonic features by performing spatial analysis of potential fields. The overall methodology comprises gravity and magnetic data filtering, followed by lineaments mapping and cross‐referencing interpretation with available seismic reflection data. This process allows delineating zones of crustal weakness by extrapolating outside our three 2‐D models. We also map multiple seamounts that appear to cluster along identified zones of weaker crust. Third, we investigate the relationship between the mapped tectonic elements, namely the zones of weak crust with accompanying seamounts, and the observed seismicity trends within the subducted slab. The alignment between those suggests that mapped weak crust zones and associated seamounts may have an influence on the overall subduction process. As more of these structures are heading toward the Washington portion of the margin than to the Oregon portion, more earthquakes are observed in the north than in the south.

Influence of physical-property variations on leakage for supercritical CO2 seal

In the supercritical CO2 Brayton cycle, dynamic sealing of rotating machines is one of the critical technologies. Under drastic variations of physical properties, the flow characteristics, sensitivity of parameters to leakage, and feasibility of theoretical models are not well understood. Experimental parameters of labyrinth seals include upstream parameters (302.15 K to 379.15 K, 7 MPa to 14 MPa) and pressure ratios (1.05 to 1.60, below the critical flow) covering trans-critical and pseudo-critical conditions. A comparison between experiments and traditional models leads to the following conclusions: In terms of linear correlation with the leakage, the upstream parameters in the density form are significantly superior to those in the temperature form. For the expansion factor part, the isentropic form can lead to errors ranging from -25% to 45%. In model prediction, the use of both temperature-based and isentropic-based parameters can result in significant prediction errors ranging from -41% to 67%. This paper recommends Martin's model with the density-based upstream parameters, the iterative isentropic model, and the Childs model, each with an error of ±10% or less.

Physical and Chemical Properties of Highland Bamboo (Yushania alpina) Culms Grown in Ethiopia

Bamboo is the fastest growing plant currently known on earth, a property that enables it to be the best alternative as a future source of wood fi ber. This study investigated the effect of site and culm height on the physical and chemical properties of Yushania alpina culms grown in Ethiopia. Matured Yushania alpina 3 to 5-year-old samples were harvested from Hagere-Selam and Rebu-Gebeya sites. The culms were subdivided into three equal lengths (bottom, middle, and top), and the variations in physical and chemical properties between the two sites and the culm heights of Yushania alpina were investigated. The results showed that the average values of MC, basic density, tangential and longitudinal shrinkage of Yushania alpina culms for Hagere-Selam and Rebu-Gebeya sites were (91.78 and 80.32 %), (0.65 and 0.63 g/cm3), (6.63 and 5.84 %) and (0.63 and 0.56 %), respectively. The average values of cellulose, lignin, extractive and ash contents in the culms for Hagere-Selam and Rebu-Gebeya sites were (52.84 and 50.71 %), (26.55, and 26.04 %), (8.41 and 8.02 %) and (1.95 and 2.17 %), respectively. The results revealed that the site affected the MC, basic density, cellulose, lignin, extractive, and ash contents of Yushania alpina culms but not the tangential and longitudinal shrinkage. The culm height of Yushania alpina affected MC, basic density, tangential shrinkage, longitudinal shrinkage, cellulose, lignin, extractive, and ash contents. In the case of both sites, the highest percentages of MC, tangential and longitudinal shrinkage, and ash content were observed at the base and lowest at the top of the culms. On the contrary, both sites observed thehighest magnitude of basic density, cellulose and extractive at the top and lowest at the base of the culms. The variations in physical and chemical properties at different sites and culm heights infl uence the utilization of Yushania alpina culms for industries and end products.

Novel experimental technique to evaluate soil thermal conductivity in a transient state

novel experimental technique to evaluate soil thermal conductivity in a transient state

Achieving controllable multifunctionality through layer sliding

Dynamical variation of physical properties in a controllable fashion provides exciting possibilities to obtain multifunctional materials. In this work, layer-sliding is employed to modify the structural, interfacial electronic and optical properties of unintercalated and Mg-intercalated two-dimensional (2D) van der Waals heterostructure (vdW-HS) consisting of buckled silicene and hexagonal boron nitride (hBN). The most stable stacking configuration of silicene over hBN is screened out and then intercalated with Mg at the interface. Dynamical-dependent changes in the properties of vdW-HS are performed by sliding silicene over hBN monolayer in the absence and presence of the intercalant. Layer-sliding is carried out in equal length intervals, and various parametric quantities related to the physical characteristics of the vdW-HS are repeatedly calculated and compared. Apart from various parametric quantities, stability of unintercalated and Mg-intercalated vdW-HS is also checked by means of relative total energies, binding energies and vdW gaps along the sliding pathway. Comparison of binding energies shows that the un-slided, half-slided, and fully-slided Mg-intercalated vdW-HS are 1.52, 1.44 and 1.42 eV more stable than the unintercalated vdW-HS. Opening of a small band gap of 12, 31 and 28 meV for un-slided, half-slided and fully-slided unintercalated vdW-HS, respectively, is worth mentioning. To study the interfacial electronic behavior, planar average charge density difference (Δρ) and charge transfer (ΔQ) are also calculated and varied via layer-sliding. Further, we calculated diverse optical spectra such as the complex dielectric function (DF), electron energy loss function [L(ω)], diagonal components of dielectric tensor [ε(iω)], refractive index [n(ω)], extinction coefficient [k(ω)], absorption coefficient [α(ω)], and reflectivity [R(ω)] for un-slided, half-slided and fully-slided unintercalated and Mg-intercalated vdW-HS. Interestingly, the polarization and energy losses have been reduced in the case of Mg-intercalated vdW-HS. The suggested layer-sliding method can be established as a general scheme for bringing multifunctionality into a layered material.

The different action mechanisms of silica and alumina nanoparticles in lime-pozzolan pastes

The purpose of this study is to compare the mineralogical and the chemical modifications of lime-pozzolan pastes with increasing proportions of nano-silica (NS) and nano-alumina (NA) particles, respectively. The action of the nanoparticles was found different and the results can explain the variation of physical and mechanical properties that were recorded in previous studies. NS action was synergetic to the pozzolanic reaction between the binders, whilst NA action was found competitive to the pozzolanic reaction as it strengthens carbonation. Analysis with XRD and ATR-FTIR advocate this result revealing the reaction mechanisms.

Estimation of Physicochemical Properties in the Estuarine Water of Mithbav Tidal Mud Flats (Downstream Part), Coastal Maharashtra

Estuarine environments have become crucial in coastal areas nowadays. Mangrove swamps, mudflats and related estuarine environments provide a habitat for animals and encourage plant growth. For the people of coastal areas, estuaries are one of the vital sources of food and other economic activity. The imbalance in the quality and quantity of Estuarine water in terms of its physicochemical parameters causes adverse effects on marine life. In the present study, an attempt has been made to estimate the physicochemical properties of the estuarine water of Mithbav tidal mud flats (downstream part) of coastal Maharashtra. Several methods have been used to evaluate the variations in physical and chemical properties of estuarine water in Mithbav including standard water testing,1 the titration method and Winkler's method. Salinity, turbidity, pH, total hardness, DO, TDS, EC, nitrate, fluoride, phosphate, ammonium, magnesium, calcium, carbonate, chloride, sodium, potassium and sulphate were examined for the seven cross-sectional sites of Mithbav estuarine water. Some parameters show levels of contamination that exceed the maximum limit. For instance, during the post-monsoon season, the average value of dissolved oxygen (DO) was recorded as 11.57mg/L whereas it has been recorded as 8.07mg/L during the summer season. The total dissolved solids (TDS) showed an average increase from 141.54 to 348.57ppt between pre and post-monsoon seasons. The electrical conductivity (EC) also increased from 45558.17μ S/Cm to 31445.85 μ S/Cm respectively from the dry to the wet season. The fluoride levels during the post-monsoon season ranged from 1.07 mg/L at CS-1 to 4.2 mg/L at CS-6. The study shows that the Mithbav coastal ecosystem and nearby areas are at significant risk of contamination from physiochemical parameters that could harm the environment.