Search

This study investigates the measurement of plasma‐grown nanoparticles, comparing ex situ scanning electron microscopy (SEM) and an in situ light scattering method which is based on Mie theory and utilizes a neural network for evaluation. The research reveals that the particle size distribution (PSD) is normal and very narrow, supporting the common assumption of monodisperse particle clouds. Importantly, the study finds that the spread of the PSD increases proportionally with the mean size, suggesting varied growth rates based on the radius of the spherical dust grains. Both methods produce consistent results, which encourages the use of the interference‐free, real‐time, light‐based Mie method in similar studies. [ABSTRACT FROM AUTHOR]

The study's objective was to assess the particle-size distribution and formulate an empirical model for the content of the finest dust created during the sanding of unmodified and thermally modified pine wood. The experimental design included unmodified and two options of thermally modified pine (Pinus sylvestris L.) wood samples, four feed speeds (3; 6; 9; 12 m·min−1), and three grit sizes of sanding belts (P60; P80; P100). The wood dust samples underwent sieve analysis to determine the particle-size distribution and laser analysis to determine the content of the finest particles. The sanding of thermally modified wood produced a higher amount of fine dust compared to unmodified wood. The content of fine dust increased with decreasing feed speed, while larger grit sizes resulted in increased production of fine dust. The average mass share of dust < 2.5, < 4, and < 10 µm was significantly lower when sanding the unmodified wood than thermally modified wood. The influence of feed speed, grit size, and material type on dust creation suggests that thermal modification is a factor in increasing the content of the potentially harmful finest particles (respirable fraction). The presented empirical model can help minimize health risks during the sanding of thermally modified pine wood by adjusting the sanding parameters. [ABSTRACT FROM AUTHOR]

We have studied soils of the western coast of the Chivyrkui and Barguzin bays on the Svyatoi Nos Peninsula, which is the largest peninsula of Lake Baikal in the Republic of Buryatia. Morphogenetic characteristics of soils on the main types of coasts of the peninsula—low abrasion with isolated lagoons, low abrasion, accumulative, and ingression—are given. Rocks in the basis of the coasts of the bays are an important factor of soil formation. It is shown that the genesis of soils depends on the distance from the lake and the altitude, resulting in the difference in their structure and properties. The soils are not directly affected and flooded by lake water due to high mountainous coasts, which are often rocky with steep slopes. Soil formation beyond the floodplain regime is also typical for soils of the closest to the lake level: soddy podzols, which occupy low shores of accumulative types. The particle-size composition of the studied soils varies widely from loose sand to light clay. The common properties of soils include acid and weakly acid reaction, the regressive-accumulative type of humus distribution, and differentiation of bulk oxides along the profile. The revealed evidences of podzolization in Al–Fe-humus soils and of clay accumulation in brown soils are related to sufficient moistening of the coasts and the warming effect of the lake water mass. The research results may be used in landscape planning in territorial organization and monitoring work in recreation areas. [ABSTRACT FROM AUTHOR]

Shihwa Lake was an artificial freshwater lake formed in 1994 by constructing a 12.7-km-long seawall, but it became a seawater lake in 1997. The water quality of Shihwa Lake had not been recovered despite the seawater exchange through the drain gate. This may adversely affect not only the water but also the bottom sediment environment of the lake. To determine the possible reasons for the environmental deterioration, water and core samples from three points in the lake were collected. And the parameters, such as the water temperature, salinity, dissolved oxygen (DO), particle distribution, total carbon (TC) and total nitrogen (TN), C/N ratio, and radioactive strength, were measured to estimate the water and sediment quality. In addition, we investigated changes in the sedimentation environment based on heavy-metal analysis, stable-isotope analysis of the core sample, and numerical analysis of sand transport. The core-sample analysis revealed a change in the sedimentation process on a time basis (before, during, and after the construction of the seawall). As a result, the sedimentation rate was approximately 4 cm/year during the seawall construction and 2 cm/year after the construction near the center of the lake. Furthermore, we established that the trends in these calculated sedimentation rates, determined using the radioactive strength method, align consistently with the results obtained from simulations and ultrasonic-wave observations. Finally, we evaluated the effects of a tidal power plant on the exchange of seawater and sedimentation processes.

[Display omitted] • Biochar could reduce 6% CO 2 , 66% CH 4 and 32% NH 3 emissions. • Particle size distributions of compost tend to be smaller. • Wheat straw biochar improves proportion of < 200 μm size distributions. • Wheat straw biochar improves aerobic layer thickness (Lp) and oxygen infiltration. • Along the compost material to biochar, aromatic compounds are gradually increasing. In recent research, biochar has been proven to reduce the greenhouse gases and promote organic matter during the composting. However, gas degradation may be related to the microstructure of compost. To investigate the mechanism of biochar additive, composting was performed using swine manure, wheat straw and biochar and representative solid compost samples were analyzed to characterize the mixed biochar and compost particles. We focused on the microscale, such as the particle size distributions, surface morphologies, aerobic layer thicknesses and the functional groups. The biochar and compost particle agglomerations gradually became weaker and the predominant particle size in the experiment group was < 200 μm. The aerobic layer thickness (Lp) was determined by infrared spectroscopy using the wavenumbers 2856 and 1568 cm−1, which was 0–50 μm increased as composting proceeded in both groups. The biochar increased Lp and facilitated oxygen penetrating the compost particle cores. Besides, in the biochar-swine manure particle interface, the aliphatic compound in the organic components degraded and the content of aromaticity increased with the composting process, which was indicated by the absorption intensity at 2856 cm−1 decreasing trend and the absorption intensity at 1568 cm−1 increasing trend. In summary, biochar performed well in the microscale of compost pile. [ABSTRACT FROM AUTHOR]

The fragmentation/adhesion behavior of nanoparticle agglomerate collision, which is challenging to model, is a crucial factor affecting fluidization. In this study, a discrete‐finite element method (FDEM) based cohesive crack model is developed to simulate normal collisions between a complex agglomerate (around 1 mm) and a wall. In the FDEM model, the complex agglomerate is built from primary agglomerates (around a few micrometers), whose adhesive force and Young's modulus are measured by an atomic force microscope (AFM). The simulation results including fragmentation morphology and plastic deformation agree well with the collision experiments. Finally, the sensitivity of the model is tested, including adhesive force, solid holdup, and Young's modulus. Fragment distribution is found to fit well with a two‐parameter Weibull function and damage ratio is found to have a polynomial relation with a modified Weber number. The model output shows a potential to be utilized in macroscopic model. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Refrigeration is the property of Journal of Refrigeration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The soil specific surface area (SSA) is an important variable for soil science and geoenvironmental engineering applications, but traditional measurement methods are difficult and time-consuming. Regression models or pedotransfer functions are often used to estimate SSA from other soil properties (e.g., clay content and cation exchange capacity), but these models do not consider the impact of clay mineralogy. Hygroscopic water content (wh) is intimately linked to these soil properties, which suggests that wh may be a better parameter for SSA estimation. This study (i) proposes regression models that estimate SSA from wh at different relative humidity values (5 to 90%) for kaolinite-rich samples (KA), illite-rich or mixed clay samples (IL/MC), montmorillonite-rich samples (ML), and a combination of all samples (ALL) and (ii) compares the performance of the wh models to other published models that comprise clay, silt and soil organic carbon contents and cation exchange capacity. We found that the sample-specific wh regression models accurately estimated SSA for KA, IL/MC and ML samples. For KA and IL/MC samples, the performance of the KA model (e.g., for adsorption, average RMSE = 10.5 m2/g) and IL/MC model (average RMSE = 21.3 m2/g) were better than the ALL-calibration model (KA: average RMSE = 18.7 m2/g; ML: average RMSE = 22.4 m2/g). For ML samples, similar model performance between the ML-calibration model (average RMSE = 41.4 m2/g) and the ALL-calibration model (average RMSE = 41.1 m2/g) was observed. In addition, the model performance of regression models based on wh was superior to models published in the literature that are based on clay, silt and soil organic carbon contents and cation exchange capacity. Overall, this study confirms that a single measure of wh can provide reliable estimates of the SSA while revealing a significant impact of clay mineralogy on model performance.

In order to explore the effect of particle-size distribution (PSD) on the shear characteristics and deformation characteristics of slip zone soil, 13 sets of medium-sized shear tests were designed by using the mixture test design method. The mathematical expressions of the fractal dimension D and traditional PSD parameter Cu were deduced, and a mixture model was established to predict the internal friction angle of soils with different PSD. Two tests were then used to verify the correctness of the model. The visualized shear box facilitates the recording of soil deformation characteristics during shear. Interval photography was used to record the deformation information of the soil during shear, which was extracted by using Particle Image Velocimetry technology and displayed using Tecplot software. These features were examined and considered for connections with D. The results show that the mixture test can be used as a means to study PSD, and D can describe the change of PSD and link the macroscopic strength of the soil with the mesoscopic properties. Understanding the mechanical properties of soils under different PSD and explaining them at the mesoscopic level can help to better understand the mechanism of landslides and can also provide a basis for the selection of PSD for subgrade soil.

In order to explore the effect of particle-size distribution (PSD) on the shear characteristics and deformation characteristics of slip zone soil, 13 sets of medium-sized shear tests were designed by using the mixture test design method. The mathematical expressions of the fractal dimension D and traditional PSD parameter C u were deduced, and a mixture model was established to predict the internal friction angle of soils with different PSD. Two tests were then used to verify the correctness of the model. The visualized shear box facilitates the recording of soil deformation characteristics during shear. Interval photography was used to record the deformation information of the soil during shear, which was extracted by using Particle Image Velocimetry technology and displayed using Tecplot software. These features were examined and considered for connections with D. The results show that the mixture test can be used as a means to study PSD, and D can describe the change of PSD and link the macroscopic strength of the soil with the mesoscopic properties. Understanding the mechanical properties of soils under different PSD and explaining them at the mesoscopic level can help to better understand the mechanism of landslides and can also provide a basis for the selection of PSD for subgrade soil. [ABSTRACT FROM AUTHOR]

Summary: The feasibility of predicting at laboratory‐scale the fouling propensity of orange juice suspended particles based on their physical properties, was investigated. Samples were generated from mixtures of two selected size class of large and fine particles. The particle‐size distribution, rheological and textural properties of these samples were characterised as well as their fouling propensity using permeability test. Qualitative and quantitative statistical analyses revealed significant correlations between specific resistance to filtration (SRF) and hydration velocity (Vh), statistical diameter (D90) and shear strain at flow point (ɣf). Partial Least Square method allowed to discriminate contrasted values of log(SRF) of suspended particles using a simplified model (R2 = 0.79; RMSEC; RMSECV <20% of SRF mean; RPD = 1.6), based on 5 predictor variables (Vh, ɣf, D90, D[4;3] and Ec). These findings, offer new prospects to guide the choice of pretreatment or specific operating conditions to improve the performance of fruit juices microfiltration. [ABSTRACT FROM AUTHOR]

In the literature, mainly particle-size distribution (PSD) analyses in the soil catenas, of e.g., moraine and riverine landscapes were discussed. Analysis and comparison of PSD in moraine (ML) and ice-dammed lakes (ID-LL) landscapes were not studied. Since the landscape of ice-dammed lakes origin has diversified relief and is under intensive agricultural use, the aspects of erosion are of great importance. The changes in PSD were studied in 14 soil catenas (toposequences) of eroding soils at the upper slope (US) as well as colluvial soils at the middle (MS) and lower (LS) slopes and in the depressions (D). The PSD of the fine fractions (<2 mm) was analysed according to the hydrometer method. In order to describe the effect of agricultural use on the variability of PSD in soil surface horizons, sedimentological and granulometric indices were calculated. In the studied moraine landscape, the content of coarse silt fraction was increasing in the catenal sequence from 9.7% in the US to 17.7% in the D. Similar relationships were revealed for the fine silt content. Significant differences were found between the average contents of coarse and fine silt fractions at the US as well as the LS and the D. However, such a relation was not found in the soil catena in the ice-dammed lake landscape. Eroded and colluvial soil materials were very poorly sorted with a standard deviation index of 2.65–3.69. Humus horizons of analysed soils had very fine, fine skewed PSD, mesokurtic and platykurtic distribution (ML), symmetrical, fine skewed and platykurtic distribution (I-DLL). The cluster analysis enabled the separation of two groups of soils: one group in the moraine landscape and the other in the ice-dammed lakes landscape. The PSD in studied soils was similar only among the soils within one type of landscape. [ABSTRACT FROM AUTHOR]

The paper presents the study of polymer compositions based on ABS plastic and ED-22 epoxy resin, which contained ferromagnetic iron powders and modified carbon nanotubes. We show the influence of Taunit MD carbon nanotubes, introduced into the composition of radio-absorbing materials in addition to magnetic powders, on their radiotechnical characteristics. The dependences of the radiotechnical characteristics of polymer compositions on the concentration of functional fillers—iron powders and carbon nanotubes—have been determined. The effect of separation of functional fillers into separate phases in a two-matrix composite material is shown. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the issue of sandy soil contamination by oil hydrocarbons. Laboratory procedures used to study conditionally pure and contaminated sands include grain-size measurements and evaluation of physical-mechanical and hydrophysical properties. The results of the analysis of sand samples using visual and microscopic studies and sieve analysis show that, unlike in conditionally pure sands, in contaminated samples, the surface of mineral particles is covered by hydrocarbon film. The presence of the latter enables micro- and macroaggregates to be formed. Studies of the physical and hydrophysical properties of sands using a technique with pre-weighed glass containers, as well as a filtering device, SPETSGEO pipes, showed that, in comparison with conditionally pure samples, contaminated specimens of sandy soils have lower densities and higher permeabilities and water yields. Testing the mechanical properties of contaminated sands on the GPP-30 direct shear apparatus using the consolidated dried shear strength method revealed an increase in the angle of internal friction with a decrease in specific adhesion compared to conditionally clean sands. [ABSTRACT FROM AUTHOR]

The quality of lime is generally estimated by traditional methodologies, which consist of coarse granulometry and chemical reactivity determinations. Performing a detailed chemical/mineralogical and fine granulometric characterization is the objective of this study. Fifteen lime samples, from an original 52 commercial samples, were analyzed by their granulometric profile (GP) and chemical-mineralogical compositions to discuss limestone quality inside the tree group of traditional efficiency neutralizing power (ENP) and Mg contents. The lime reactivity was estimated using laser diffraction under water and acid solution (1 mol L−1 HCl). The grain-size distribution ranged from 0.563 to 1124 µm and the GP was associated with the chemical and mineralogical compositions. Samples with high ENP (>99%) presented differences in GP regarding Mg contents. Lime with low ENP presents the most varied mineral assemblage, while calcite and dolomite were the predominant minerals in high-ENP samples. Samples containing high Mg were the most sensitive to the acid solution, suggesting great reactivity. This work contributes to a better understanding of limestone quality than routine analyses performed so far. Additionally, the use of the laser diffraction method promotes a rapid lime reactivity test for liming purposes. [ABSTRACT FROM AUTHOR]

Methods of mathematical statistics were used in this article to study the processes of sedimentogenesis and early diagenesis of surface sediments in the Kara Sea. Correlation analysis established two groups of oxides associated with certain particle-size types of deposits. The one-way analysis of the variance revealed the regularity of the sand, silt, and pelite distribution in accordance with sedimentation conditions by differences in their mean contents. These data were used to compile maps of the sand, silt, and pelite distribution within the studied area of the Kara Sea. Some features of the main factors of sedimentogenesis in this region were revealed on the basis of statistical data. The relationship between the Mn/Al, Mn/Fe, and MnO/SiO2 ratios and depth established by the univariate regression analysis enabled us to study the intensity of early oxidative diagenesis within the shelf zone of the Kara Sea. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effect of temperature in the range from 4 to 50°C on the water retention curves in five soil samples of different textures was studied. The method of thermostatic centrifugation on the basis of a laboratory centrifuge Sigma 2-KHL (Germany) was used, which made it possible for the first time to evaluate the influence of the temperature factor in a wide range of the thermodynamic potential of water from 0 to 3000 J/kg. Using statistical methods, two physically-based hypotheses of the relationship between temperature and thermodynamic potential—"capillary" (a decrease in water retention with increasing temperature) and "surface forces" (temperature invariance of water retention)—were evaluated. A representative analysis of 4–8 repetitions of each experiment did not reveal a statistically significant effect of the temperature factor on the water retention curves in all the studied samples. A fundamental explanation of the obtained results is proposed on the basis of Polanyi's potential theory and the ion-electrostatic mechanism of disjoining water pressure according to Deryagin. [ABSTRACT FROM AUTHOR]

The challenges to regulate the particle-size distribution (PSD) stem from on-line measurement of the full distribution and the distributed nature of crystallization process. In this article, a novel nonlinear model predictive control method of PSD for crystallization process is proposed. Radial basis function neural network is adopted to approximate the PSD such that the population balance model with distributed nature can be transformed into the ordinary differential equation (ODE) models. Data driven nonlinear prediction model of the crystallization process is then constructed from the input and output data and further be used in the proposed nonlinear model predictive control algorithm. A deep learning based image analysis technology is developed for online measurement of the PSD. The proposed PSD control method is experimentally implemented on a jacketed batch crystallizer. The results of crystallization experiments demonstrate the effectiveness of the proposed control method. [ABSTRACT FROM AUTHOR]

Phytogenic mounds (nebkhas) formed by shrubs are a common phenomenon in arid and semi-arid areas. The formation of nebkhas is accompanied by the appearance of the fertile island effect. Quantitative evaluation of the shrub sand compost island effect is a key link in preventing soil erosion and nutrient loss. This study took the typical shrub Tetraena mongolica in desert areas as the research object and quantified the sand-trapping capacity of the shrub. We revealed the influence of sediment texture and volumetric soil water content on fertile islands during the development of T. mongolica nebkhas. The results showed that (1) the single shrub intercepted large amounts of sediments due to the high density of branches of T. mongolica, forming nebkhas that were positively correlated with the shrub size. (2) The overall soil nutrient content below the shrub was greater than the soil nutrient content outside the shrub, forming a typical fertile island effect. The soil organic carbon (SOC), alkaline hydrolytic nitrogen (AHN), available phosphorus (AP), and available K (AK) content all increased gradually with increasing nebkha volume. Compared with the deep soil of nebkhas, the nutrient content of the surface soil was generally higher. (3) There was a positive correlation between the volumetric water content and nutrient content in nebkhas. (4) The semi-ellipsoid shape of T. mongolica enabled it to intercept large amounts of coarse-grained material. Fine sand (100–250 µm) was the main particle size in the sediment aggregates inside the nebkhas. The fine sand content generally increased with increasing shrub size. Redundancy analysis (RDA) revealed that the fine sand content of the nebkha sediments had a strong positive correlation with the soil nutrient content. This paper provides an example for evaluating the fertile island effect during the deposition process of nebkhas in the desert transition zone. [ABSTRACT FROM AUTHOR]

Soil structure at the basin scale affects the superficial moisture content, heat, salinity balance, and ecological balance of groundwater system. To study the soil particle size fractal characteristics at the basin scale, 188 groups of soil samples were collected over a distance of 258 km in the Ziya River basin of the North China Plain. Particle volume percent was measured using a laser particle size analyzer, and then analyzed by applying the fractal theory to reveal the spatial distribution of soil particle size and soil voids. The results showed that: (1) From the Taihang Mountain piedmont to the coastal area, soil particle-size volume percentages varied in a small range, with the fractal dimension D showing an overall decreasing trend; (2) D showed a significant spatial variation, ranging from 0.13 to 2.188. It was jointly determined by particle uniformity and particle size range; (3) When D ≤ 1, the characteristic fractal size was 30 μm in the basin. When 1 < D ≤ 1.5, the characteristic fractal size was 20 μm and D a was 1.37, and when D > 1.5, the two parameters were 10 μm and 1.77, respectively. The research results indicated that D can effectively quantify the characteristics of soil structure at a large scale.

• Hand-feel soil texture classes used as predictors in a pedotransfer function. • Clay and silt content simulated from distributions by hand-feel texture class. • Confusion in hand-feel texture class allocation is considered. • Confusion in hand-feel texture classes propagated to uncertainty in the prediction. Pedotransfer functions (PTFs) are increasingly being used to derive difficult-to-measure or cost prohibitive soil properties from more readily available soil data. Soil texture (ST) is one of the most commonly used predictors in PTFs. Soil texture can be determined in the laboratory or estimated manually by soil surveyors in the field. Soil texture classes are sometimes used either for producing class PTFs or to generate distributions of clay, silt and sand. Here, we develop a method to assess the uncertainty due to the confusion or error in hand-feel soil texture (HFST) classes allocation. We show that this error does not have a large impact on the coefficients of the linear regressions used to calibrate the PTFs. However, they may have a large impact on PTFs prediction performances. [ABSTRACT FROM AUTHOR]

Particle-size distribution plays an important role in synthesis cost and overall structural parameters of geopolymeric membrane. In this research work, the effect of particle-size distribution on the pore size, porosity, and compressive strength was investigated in the synthesis of geopolymeric membranes. The average particle-size distribution of 4.30, 23.30, 46.20, 65.32, 86.24, and 98.53 μm of fly ash was investigated separately based on pore size, porosity, and compressive strength of prepared geopolymeric membrane using sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) as a chemical activator and hydrogen peroxide (H2O2) (10 v/v %) as a pore-forming agent. Compressive strength of 13 MPa with 48% porosity and more uniform pore size has been obtained at source material with a particle-size distribution of 23.30 μm. No significant change in the compressive strength of the prepared membrane has been observed for source material particle sizes below 23.30 μm. The results show that there is no need for energy and cost-intensive very fine grinding below 23.30 μm as the particles were completely dissolved in an alkaline solution. A permeate flux of 40.53 L/m² h and 93% rejection of total solids were reported for the membrane prepared from 23.30 μm particle size. [ABSTRACT FROM AUTHOR]

The effects of phosphorylation pre-treatments at 1.5, 2.5, and 3.5% levels, as well as microwave application at 200, 400, and 700 watts levels for 2 min, on the functional parameters of egg white powder obtained by the freeze dryer procedure were investigated. P1.5-M200 had the highest oil-holding capacity, emulsion stability, and emulsion activity, while P2.5-M200 had the highest foam capacity. The P2.5-M400 had the largest particle size, and P3.5-M200 had the highest degree of phosphorylation and protein solubility. On the other hand, P3.5-M200 had the highest solution viscosity by 1% (w/v), water-holding capacity, and foam stability, in the treatments that used phosphorylation and microwave treatment simultaneously. FTIR spectroscopy of the unfolding structure of egg white protein revealed changes in the protein's secondary structure, such as the development of β-sheets and β-turns, as well as the binding of negatively charged phosphate groups on the serine, threonine, and tyrosine side chains. The phosphorylation and microwave treatments reduced the particle size of the egg white protein powder while increasing the surface area of the protein molecules, according to SEM analyses. [ABSTRACT FROM AUTHOR]

Motivated by a wide range of applications in various fields of physics and materials science, we consider a generalized approach to the evolution of a polydisperse ensemble of spherical particles in metastable media. An integrodifferential system of governing equations, consisting of a kinetic equation for the particle-size distribution function (Fokker–Planck type equation) and a balance equation for the temperature (concentration) of a metastable medium, is formulated. The kinetic equation takes into account fluctuations in the growth/reduction rates of individual particles, the velocity of particles in a spatial direction, the withdrawal of particles of a given size from the metastable medium, and their source/sink term. The heat (mass) balance equation takes into account the growth/reduction of particles in a metastable system as well as heat (mass) exchange with the environment. A generalized system of equations describes various physical and chemical processes of phase transformations, such as the growth and dissolution of crystals, the evaporation of droplets, the boiling of liquids and the combustion of a polydisperse fuel. The ways of analytical solution of the formulated integrodifferential system of equations based on the saddle-point technique and the separation of variables method are considered. The theory can be applied when describing the evolution of an ensemble of particles at the initial and intermediate stages of phase transformation when the distances between the particles are large enough, and interactions between them can be neglected. [ABSTRACT FROM AUTHOR]

In order to study the relationship between multifractal characteristics of particle-size distribution (PSD) and unsaturated hydraulic conductivity, taking the Hunan clay as the research object, we analysed the particle composition of the whole particle size range by a laser particle size analyser, and discussed the multifractal characteristics of PSD by using the fractal theory. The soil–water characteristic curve (SWCC) and unsaturated hydraulic conductivity were measured by the pressure plate instrument and instantaneous profile method, and the unsaturated hydraulic conductivity was predicted by the fractal model. The results show that the fractal dimension D is not a fixed value for the Hunan clay with the whole particle size range, which exhibits obvious multifractal characteristics. The value of fractal dimension D is closely related to the investigated particle size range. The larger the particles in the particle size range, the larger the corresponding fractal dimension D. By comparing the measured and predicted values of the unsaturated hydraulic conductivity, it is found that the prediction results of fractal dimension D for unsaturated hydraulic conductivity with different particle size ranges are quite different, and that those results with larger particle size ranges are more reasonable. [ABSTRACT FROM AUTHOR]

In this study, sodium methylsilicate and lime were selected to prepare the same proportion of Imitation Site Soil, and according to the principle of carbonation reaction of restoration materials, the effect of carbonation reaction on the performance of restoration soil of earthen sites was studied. The study has good significance for the conservation and restoration of earthen sites. The samples were cured with CO2 concentration and curing age as variables. After curing, the samples were tested to determine their water-resistant properties, uniaxial compressive strength, and pH value and a micro scanning electron microscope was used. The results indicated that the carbonation reaction can quickly improve the water resistance and compressive strength of imitation site soil, and reduced the water absorption by 16.67% compared to the specimens conditioned at 0.03% CO2 concentration. The UCS of specimens at 5%, 10%, and 15% CO2 concentrations increased by 72.22%, 131.19%, and 219.27%, respectively, compared with those at 0.03% CO2 concentration after the specimens were environmentally maintained in the carbonation chamber at 0.03%, 5%, 10%, and 15% CO2 concentrations for 120 h, respectively. The internal particle gradation of the imitation site soil improved after carbonation. These results provide a basis for improving the restoration technology of earthen sites. [ABSTRACT FROM AUTHOR]

This study introduced a four-way CFD-DEM coupling approach to simulate the shear-induced particle migration (SIPM) mechanism leading to formation of the lubrication layer (LL) during concrete pumping. The CFD-DEM simulations considered the coupled effect of concentration (10 %–40 %) and wide size distribution (1–17 mm) of aggregate and rheology of the mortar for forces between the suspending matrix and the particles (and vice versa), as well as force transmission directly between particles (and the pipe wall). The formation of the LL was successfully simulated through a more realistic understanding the SIPM mechanism and rheological evaluation across the pipe with comparable calculation times compared to the one-way coupled DEM approach, especially for high concentrations. The simulated LL thicknesses of 0.8–2.7 mm compared well with experimental values. The flow rate and rheological heterogeneity of pumped concrete, and rheology of the LL, were found mostly controlled by the granular-skeleton characteristics rather than the suspending-matrix rheology. • Four-way CFD-DEM coupling to simulate concrete pumping as a multiphasic suspension • Modeling shear-induced particle migration leading to formation of lubrication layer • Superior accuracy of CFD-DEM coupling approach to simulate SIPM compared to DEM • Coupled effect of PSD and φ/φ max of aggregate and mortar rheology on pumpability • Characterization of lubrication layer in terms of rheological properties and thickness [ABSTRACT FROM AUTHOR]

[Display omitted] • Modelling of H 2 -TPR patterns considering the effect of particle size distribution. • Three pure metal oxides were used to selecte the kinetic reaction models. • Three reaction kinetic models were considered. • Information of the metal oxide is derived from the Prout and Tompkins model. Hydrogen temperature-programmed reduction (H 2 -TPR) has become a very useful and common technique for the chemical characterization of solids as it is sensitive to the study of reducible species in catalysis and is considered to be a fingerprint for the reducibility of metal oxide catalysts. However, although modeling of H 2 -TPR patterns has been extensively studied, little attention has been paid to the effect of particle-size distribution (PSD). The complexity of modeling H 2 -TPR patterns arises from the fact that the chemistry of metal oxide reduction depends on several factors, including particle size, nature of the support material and confinement within the porous structure, amongst others. In order to identify the kinetic reaction model governing the reduction of certain metal oxides and to explore the effect of PSD, pure metal oxides that only exhibited the particle size difference effect were used to model the H 2 -TPR patterns. Kinetic and thermodynamic data, which are very useful for characterizing heterogeneous catalysts, were obtained from this study. This work presents a simple procedure for modeling H 2 -TPR patterns of various metal oxides (i.e., CuO, Ag 2 O, and NiO) used as active phases in several reactions of environmental and energetic interest using several solid-state reaction kinetic models and considering their PSDs. The results obtained show that modeling the H 2 -TPR profiles provides information regarding the PSD of metal oxide catalysts that undergo a single-step reduction and only present the particle size difference effect. [ABSTRACT FROM AUTHOR]

In the literature, mainly particle-size distribution (PSD) analyses in the soil catenas, of e.g., moraine and riverine landscapes were discussed. Analysis and comparison of PSD in moraine (ML) and ice-dammed lakes (ID-LL) landscapes were not studied. Since the landscape of ice-dammed lakes origin has diversified relief and is under intensive agricultural use, the aspects of erosion are of great importance. The changes in PSD were studied in 14 soil catenas (toposequences) of eroding soils at the upper slope (US) as well as colluvial soils at the middle (MS) and lower (LS) slopes and in the depressions (D). The PSD of the fine fractions (

This article deals with the fractionation of wood dust by sieve after sanding. Dust from untreated beechwood was compared to dust from thermally modified beechwood (at 200 °C for 3 h). The authors hypothesized that the thermal modification changes the particle size distributions of the dust sieve fractions and that all the dust sieve fractions contain the finest particles, which are suspendable in the air and are potentially respirable. To obtain dust for testing, both wood materials were sanded with P120 paper at a belt speed of 14.5 m/s and a pressure of 0.65 N/cm² . A set of sieves with aperture sizes of 25, 80, and 250 µm were used to separate the dust into sieve fractions with grain sizes less than 25 µm, 25 to 80 µm, 80 to 250 µm, and greater than 250 µm. The content of the finest particles in the fractions was measured via a laser particle sizer. Both dusts had similar particle size distributions. In addition, each investigated fraction of both dusts contained the finest particles, i.e., less than 10 µm. It follows that the laser analysis method may be necessary to correctly assess the occupational risk at a sanding. [ABSTRACT FROM AUTHOR]

The mechanical potential, the durability, and the most varied uses of structures have been studied and disclosed. However, there is still a gap regarding the determination of mixing ratios using a simple, accessible mixture design method that allows the determination of the ideal ratio of mixture constituents. Some studies on ultra-high-performance concrete (UHPC) mixtures did not present a method to define the mixing ratio with different materials and fiber contents, with high mechanical strength and no workability loss. To develop a method of mixing design from informational parameters of the materials, this paper presents a method of dosing UHPC. The proposed method is based on the packaging of particles through the previous evaluation of the percentages of each material according to its particle size distribution. Results showed that the proposed mixture design method can grant high potential compressive strength to the mixture. There was also a linear relation between higher matrix compacity and compressive strength. The composition with higher compacity—that is, the lowest void ratio of the mixture—presented an increase of 20% in compressive strength compared to the mixture with less compacity. [ABSTRACT FROM AUTHOR]

The bulk density (BD), particle-size distribution and soil moisture content (SMC) are important properties that govern the physical and mechanical behaviours of the soil and also provide crucial information on the pedogenesis of soils. A total of 153 soil profiles were randomly selected and studied from part of Sepahijala district, Tripura, Northeastern India. The horizon-wise soil property data were converted to fixed-depth data for 0–20, 20–40, 40–60, 60 − 80 and 80–100 cm of soil depth. The result showed that the mean values of BD 1.51, 1.60, 1.59, 1.55 and 1.55 Mg m−3; sand 37.7, 38.1, 36.9, 36.0, and 37.3%; silt 29.1, 26.8, 28.0, 28.3 and 27.2%; clay 33.2, 35.1, 35.1, 35.7 and 35.5%; and SMC 21.4, 20.2, 21.2, 21.3 and 19.4% in the 0 − 20, 20 − 40, 40 − 60, 60 − 80 and 80 − 100 cm depths, respectively. The values of CV for soil variables ranged from 9.4 to 70.0% for all the depths. The CVs indicated that BD had lowest variability, while sand and SMC showed high variability in all the depths. Stein, circular, spherical, exponential and Gaussian models were found to be the best fit for semivariograms of different physical properties for different soil depths. The nugget to sill ratios of the empirical semivariograms for all the layers of BD, clay and SMC indicated moderate spatial dependence, except the 80 − 100 cm of BD and clay and 20 − 40 and 60 − 80 cm of SMC, which showed strong spatial dependence. Soil physical properties exhibited different distribution pattern. Spatial distribution maps of BD showed that except surface layer, the BD is lower in the southern part of the study area, and decreasing towards the northern parts in all the depths may be due to higher clay content in this region. The spatial distribution of SMC closely followed the distribution pattern of sand and clay contents. The developed maps prepared in this study may be useful to farmers, planners and decision-makers for improving soil–water management. [ABSTRACT FROM AUTHOR]

For a diesel engine, it is crucial and difficult to reduce the original particle matter emissions. Although the emission of particle matter can be reduced effectively, the engine internal purification and external purification measures can increase the cost and manufacturing process. Therefore, designing and improving oil products has become the most effective way to reduce emissions. This study compared the combustion and particle matter characteristics of diesel, diesel–rocket propellant-3 (RP3) (WDBF) with 20%, 40%, and 60% rocket propellant-3 in a single-cylinder compression ignition engine. The brake power, brake thermal efficiency (BTE), and particle matter concentration of the diesel engine were determined experimentally at three speeds (2,000, 2,700, and 3,600 r·min−1) at engine loads of 10%, 50%, and 100%. The results demonstrated that with the increase of the RP3 blending ratio, the density, cetane number, kinematic viscosity, and surface tension of diesel–RP3 WDBF decreased, whereas the low heating value increased, and T10, T50, and T90 (10%, 50%, and 90% volume distillation temperatures, respectively) decreased. The addition of RP3 to diesel increased the peak number concentration of small particles under the test conditions. The total particle number concentration (TPNC), total particle volume concentration (TPVC), and total particle mass concentration (TPMC) decreased by 14.1%–53.4%, 22.5%–75.3%, and 21.3%–39.3%, respectively, compared with that of using diesel. The change was obvious with the increase of the RP3 ratio and without impact on brake power and BTE. [ABSTRACT FROM AUTHOR]

A new method to estimate the size distribution of non‐interacting colloidal particles from small‐angle scattering data is presented. The method demonstrates that the distribution can be efficiently retrieved through features of the scattering data when plotted in the Porod representation, thus avoiding the standard fitting procedure of nonlinear least squares. The present approach is elaborated using log‐normal and Weibull distributions. The method can differentiate whether the distribution actually follows the functionality of either of these two distributions, unlike the standard fitting procedure which requires a prior assumption of the functionality of the distribution. After validation with various simulated scattering profiles, the formalism is used to estimate the size distribution from experimental small‐angle X‐ray scattering data from two different dilute dispersions of silica. At present the method is limited to monomodal distributions of dilute spherical particles only. [ABSTRACT FROM AUTHOR]

Particle-size distribution is a critical part of soil description, which is commonly measured using pipette and hydrometer methods. However, a recently developed technique, called the integral suspension pressure method, allows for the measurement of continuous particle-size distribution based on Stokes' law. The objective of this study was to evaluate the applicability of the integral suspension pressure method for measuring particle-size distribution, as an alternative to the standard hydrometer procedure. The integral suspension pressure method was tested by using a soil dataset with a wide range of organic matter contents (0.22-12.0%). Forty-nine samples were analysed with a hydrometer after organic matter removal and the results were compared with those obtained using the integral suspension pressure method. Through comparing the integral suspension pressure and hydrometer measurements, root mean square error values of 8.9, 8.1, and 11.9% were observed for sand, silt, and clay, respectively. The clay fraction was underestimated throughout the entire range of measurements. Conversely, the silt content was overestimated over the whole range of measurements, especially in samples with more than 36% silt. When compared to the hydrometer method, integral suspension pressure integral suspension pressure exhibited a tendency to misclassify the soil texture of clay loam samples but was accurate for sandy loams. [ABSTRACT FROM AUTHOR]

Road-deposited sediments (RDS) contain metals that can pollute receiving waters during precipitation events. The concentration of particle-bound metals tends to increase with decreasing particle size. In terms of metal load, the highest loads were often located in the medium range of particle sizes. Many studies have used varying or undocumented sieving techniques without showing the quality of the separation process. This is important as different particle size classes are documented with different pollution contents and loads. This knowledge builds the foundation for the selection of best management practices to improve receiving water quality. Based on the knowledge that the separation of particle sizes by the commonly applied dry sieving can be methodologically biased, this study compares particle size classes obtained by dry and wet sieving methods. The aim of the study was to show the methodological influence of the sieving process on the particle-size distribution (PSD) with focus on the metal distribution within RDS. Therefore, concentrations of Cu, Zn and Pb were determined and loads were calculated per sieve fraction after wet and dry sieving. Wet sieving causes a shift of the PSD to finer particles and both metal concentrations and loads are significantly higher especially in the smallest sieve fractions. Fine, highly polluted particles remained in coarser sieve fractions after dry sieving. This leads to diverging metal contents and especially loads in the fractions > 250 µm and thus lead to varying conclusions from the results. The results of the comparison of sieving methods however confirmed the relevance of the fine particle fractions in terms of best management practices. The fraction < 40 µm showed highest concentration and load in RDS after wet sieving. The results also showed the considerable influence of the sieving method used and the need to document laboratory methods as part of good laboratory practice.

The quality of lime is generally estimated by traditional methodologies, which consist of coarse granulometry and chemical reactivity determinations. Performing a detailed chemical/mineralogical and fine granulometric characterization is the objective of this study. Fifteen lime samples, from an original 52 commercial samples, were analyzed by their granulometric profile (GP) and chemical-mineralogical compositions to discuss limestone quality inside the tree group of traditional efficiency neutralizing power (ENP) and Mg contents. The lime reactivity was estimated using laser diffraction under water and acid solution (1 mol L−1 HCl). The grain-size distribution ranged from 0.563 to 1124 µm and the GP was associated with the chemical and mineralogical compositions. Samples with high ENP (>99%) presented differences in GP regarding Mg contents. Lime with low ENP presents the most varied mineral assemblage, while calcite and dolomite were the predominant minerals in high-ENP samples. Samples containing high Mg were the most sensitive to the acid solution, suggesting great reactivity. This work contributes to a better understanding of limestone quality than routine analyses performed so far. Additionally, the use of the laser diffraction method promotes a rapid lime reactivity test for liming purposes.

The capillary effect in polydisperse porous systems of soils and sediments is discussed. This effect is quantified using a new fundamental model of capillary rise depending on the parameters of dispersion of soil particles, soil bulk density, density of soil solid phase, wettability, and the amount of tightly bound water. In contrast to a well-known Jurin's law, the model takes into account the particle-size distributions and the change in pore size associated with soil density. The model adequately predicts the capillary rise in both artificial monodisperse porous systems and real soils with the particle size ranging from 0.006 to 1 mm. The effects of natural and synthetic hydrophobizers on the kinetics and maximum height of capillary rise are examined. The laboratory and field data on the efficiency of imperfect (with hydraulic connection) and perfect (with its rupture) capillary barriers are compared to the Hydrus-1D predictive modeling data. The results are used to evaluate the capillarity in soils and to design soil constructions with capillary barriers. [ABSTRACT FROM AUTHOR]

The paper presents soil features and chemical composition in a self‐heating coal‐waste dump. The investigations were carried out in the Upper Silesian Coal Basin. A fire zone in which the soil temperature exceeded 50°C was selected for our study. Soil analyses were carried out for three grain sizes – d > 1 mm, 0.063 mm < d ≤ 1 mm, and d ≤ 0.063 mm – enabling identification of the diversity of the chemical composition in soil fractions. The highest concentration of heavy metals is represented by Mn (212–6972 mg kg‐1), Zn (127–3283 mg kg‐1), Pb (33.6–1344.7 mg kg‐1), Cu (38.9–101.4 mg kg‐1), and major elements by Fe (14,300–117,400 mg kg‐1) and Ca (900–63,600 mg kg‐1). Soil chemistry showed variations within individual studied sites. The soil reaction ranges from acidic (4.3 in KCl and 5.26 in H2O) to moderate alkaline (7.96 in H2O and 7.31 in KCl), whereas TOC ranges from 1.21% to 14.60% and TN from 0.023% to 0.291%. The distribution of n‐alkanes clearly showed a low degree of transformation of organic matter and characteristic high values of Pr/Ph ratio for humic coals and coal waste in the region. Grains with diameters greater than 1 mm exhibited completely different features than those of fractions smaller than or equal to 1 mm. High organic carbon content (14.60) was detected in the samples along with PAHs. The influence of fire on the chemical composition of all samples was identified using geochemical indicators. PCA analysis showed that the values of the variables were more closely correlated in finer grains than in the coarsest fraction. [ABSTRACT FROM AUTHOR]

The effects of phosphorylation pre-treatments at 1.5, 2.5, and 3.5% levels, as well as microwave application at 200, 400, and 700 watts levels for 2 min, on the functional parameters of egg white powder obtained by the freeze dryer procedure were investigated. P1.5-M200 had the highest oil-holding capacity, emulsion stability, and emulsion activity, while P2.5-M200 had the highest foam capacity. The P2.5-M400 had the largest particle size, and P3.5-M200 had the highest degree of phosphorylation and protein solubility. On the other hand, P3.5-M200 had the highest solution viscosity by 1% (w/v), water-holding capacity, and foam stability, in the treatments that used phosphorylation and microwave treatment simultaneously. FTIR spectroscopy of the unfolding structure of egg white protein revealed changes in the protein’s secondary structure, such as the development of β-sheets and β-turns, as well as the binding of negatively charged phosphate groups on the serine, threonine, and tyrosine side chains. The phosphorylation and microwave treatments reduced the particle size of the egg white protein powder while increasing the surface area of the protein molecules, according to SEM analyses.

Motivated by a wide range of applications in various fields of physics and materials science, we consider a generalized approach to the evolution of a polydisperse ensemble of spherical particles in metastable media. An integrodifferential system of governing equations, consisting of a kinetic equation for the particle-size distribution function (Fokker–Planck type equation) and a balance equation for the temperature (concentration) of a metastable medium, is formulated. The kinetic equation takes into account fluctuations in the growth/reduction rates of individual particles, the velocity of particles in a spatial direction, the withdrawal of particles of a given size from the metastable medium, and their source/sink term. The heat (mass) balance equation takes into account the growth/reduction of particles in a metastable system as well as heat (mass) exchange with the environment. A generalized system of equations describes various physical and chemical processes of phase transformations, such as the growth and dissolution of crystals, the evaporation of droplets, the boiling of liquids and the combustion of a polydisperse fuel. The ways of analytical solution of the formulated integrodifferential system of equations based on the saddle-point technique and the separation of variables method are considered. The theory can be applied when describing the evolution of an ensemble of particles at the initial and intermediate stages of phase transformation when the distances between the particles are large enough, and interactions between them can be neglected.

In this study, sodium methylsilicate and lime were selected to prepare the same proportion of Imitation Site Soil, and according to the principle of carbonation reaction of restoration materials, the effect of carbonation reaction on the performance of restoration soil of earthen sites was studied. The study has good significance for the conservation and restoration of earthen sites. The samples were cured with CO2 concentration and curing age as variables. After curing, the samples were tested to determine their water-resistant properties, uniaxial compressive strength, and pH value and a micro scanning electron microscope was used. The results indicated that the carbonation reaction can quickly improve the water resistance and compressive strength of imitation site soil, and reduced the water absorption by 16.67% compared to the specimens conditioned at 0.03% CO2 concentration. The UCS of specimens at 5%, 10%, and 15% CO2 concentrations increased by 72.22%, 131.19%, and 219.27%, respectively, compared with those at 0.03% CO2 concentration after the specimens were environmentally maintained in the carbonation chamber at 0.03%, 5%, 10%, and 15% CO2 concentrations for 120 h, respectively. The internal particle gradation of the imitation site soil improved after carbonation. These results provide a basis for improving the restoration technology of earthen sites.