Changes In Particle Size Distribution Research Articles

The formation of high CO2 loading solid phase from 1,4-butanediamine/ethylene glycol biphasic solvent: Phase-changing behavior and mechanism

Liquid-solid phase change absorption has been considered a promising strategy for CO2 capture. To achieve efficient and economic CO2 capture in industrial-scale applications, it is essential to understand the phase-change behaviors and mechanisms of the biphasic system. In this study, a blend of 1, 4-Butanediamine (BDA) and ethylene glycol (EG) was developed as a biphasic solvent that can form a high CO2 loading solid phase product (BESP) after absorption. The total solvent loading reached 0.9039 mol·mol−1, with 90.74% of the loading enriched in the solid phase, which only accounts for 51.01% of the total solvent mass. Based on the 13C NMR analysis and quantum chemical calculations, the reaction and phase change mechanism of CO2 capture was proposed. The BDA/EG system absorbs CO2 to generate carbamate species, protonated amines and alkyl-carbonates, which combine each other through hydrogen bonding or electrostatic attraction. The self-aggregation of zwitterions and the high polarity of the absorption products are considered to be the main reasons for the phase change. Alkyl-carbonate species are believed to co-precipitate through organic gelation via van der Waals force with the carbamate or protonated amine. Moreover, the viscosity, turbidity, solid-phase mass, and particle size distribution changes also demonstrate the growth and aggregation of particles during absorption. BESP, identified as a coupling product of carbamate and alkyl-carbonate ([2BDAH+COO-]·[EG‐OCO2-]), decomposes at a peak temperature of 127.4 °C. The calorimetric method determined regeneration heat to be approximately 3.17 GJ·ton-1 CO2, indicating its potential for alternative uses rather than direct heat regeneration. Such a biphasic solvent may provide unique solutions for industries to reduce CO2 emissions.

The impact of material chemistry and morphology on attrition behavior of excipients during high shear blending

Particle breakage by attrition is unavoidable in some unit operations and can lead to uncontrolled behavior of materials during processing. The aim of this study is to clarify the impact of material properties on attrition behavior. For the first time, an integral study with varying morphologies and chemistries is performed to identify the key drivers that impact attrition during high shear blending. Based upon the observed changes in particle size distribution, it was concluded that dicalcium phosphate (DCP) was the most prone to attrition, followed by mannitol, lactose and microcrystalline cellulose (MCC). Granular particles were more sensitive to attrition than sieved and spherical particles. Changes in bulk density, flow function coefficient and tablet tensile strength were observed as the result of attrition. The magnitude and direction of change in these parameters was not only dependent on the amount of attrition, but also on the morphology and the material deformation properties.

Particle evolution mechanism of wide size distribution limestone under fluidized bed combustion conditions

The dynamic evolution of particles in limestone with a wide size distribution is significant for in-furnace desulfurization in circulating fluidized beds (CFB). In this study, air/SO2 mixtures were selected to simulate the flue gas combustion atmosphere, and the evolution on particle size of limestone with a wide size distribution was investigated using a self-built fluidized bed, with a focus on the evolution mechanism. The results show that the change in the cumulative particle size distribution (PSD) of limestone with a wide size distribution exhibited three stages as a function of reaction time. The cumulative PSD decreased continuously and reached 79.3% after 20 min during the first stage. The cumulative PSD was unchanged from 30 to 120 min in the second stage. The cumulative PSD increased from 81.9% to 88.3% in the range of 120–240 min during the third stage. The effects of attrition, heat stress, calcination, and sulfation on the changes in particle size were quantified and correlated with time. A novel method is proposed to predict the evolution mechanism of limestone with a wide size distribution. Calcination dominated in the time range of 0–60 min, and the predominant effect transformed from calcination to attrition at 240 min. However, the contribution of calcination was not negligible. The evolution of limestone with a wide size distribution can be promoted by the interactions of different effects.

Estimation of particle size distributions in the atmosphere—analysis of Fe and Ca particles as the representative examples

Atmospheric aerosols, including primary aerosols emitted directly into the atmosphere and secondary aerosols generated in the atmosphere from various chemically complex particles, cause a variety of environmental problems such as climate change, photochemical smog formation, and a decrease in incoming solar radiation. Therefore, it is important to understand the causes of aerosol particles and their impact on human society. In particular, particle size is an important indicator of lung penetration depth, aerosol transport, and optical properties. Hence, we mathematically estimated the airborne particle size distributions of each chemical component by collecting aerosol samples from the atmosphere using two types of cyclone samplers, large and small cyclone samplers. This study’s findings also suggest that calculated changes in particle size distribution can reflect changes in particle sources. The higher resolution of the continuous functions will enable the detection of the subtle changes in particle size distributions of each chemical component, which is helpful to understand the temporal changes in the chemical properties of the airborne aerosol particles.

CFD-DEM simulation of fluorination reaction in fluidized beds with local grid and time refinement method

The gas-solid reaction process with wide particle size distribution is extensively used in the chemical engineering field, especially the particle reacts with the gas gradually, such as fluorination reactions in fluidized beds. When the computational fluid dynamics-discrete element method (CFD-DEM) is used for the coupling simulation of multiphase and polydisperse particle reaction system, the grid size directly affects the accuracy of flow field information and simulation of chemical reaction. Furthermore, particle calculation time step will directly affect the efficiency of coupling calculation. In this work, a local grid and time step refinement method is proposed to simulate multiphase and polydisperse particle fluidization reaction system. In this method, the refined DEM grids are automatically generated in the computational domain around the fine particles, and the detailed fluid phase information is obtained with the interpolation algorithm. In the two-phase coupling process, particles are divided into different groups based on physical properties, each group has its own independent time step. The multistage conical-cylindrical spouted bed is proposed for the fluorination reaction process; the operating gas velocity range of the polydisperse particle system is extended by the new design while the particle size distribution changes with the gas-solid reaction process. It is demonstrated that the local grid and time step refinement method can improve the accuracy and efficiency of the traditional CFD-DEM method in the reaction process simulation, which describes a polydisperse particle system with wide particle size distribution. Aimed at improving the simulation accuracy and efficiency, this paper will be helpful for simulating the particle reaction process in the gas-solid fluidized bed and beneficial for the development of the CFD-DEM method.

Effect of Lipase and Phospholipase A1 on Foaming and Batter Properties of Yolk Contaminated Egg White.

Egg white (EW) is frequently used in bakery products because of its excellent foaming capabilities. However, egg yolk (EY) contamination often degrades the foaming characteristics of EW. The purpose of this study was to investigate the effect of different concentrations of phospholipase A1 (PLPA1) and lipase (LP) on EW. The changes in particle size distribution and potential before and after enzymatic digestion of EW with contaminated 0.5 wt% and 1.0%wt EY were tested. The foaming rate and foam stability were measured after the dispersions were digested with different concentrations of PLPA1 and LP. Additionally, the dispersion samples were used to prepare batter and angel cake, and the modulus, density, and microstructure of the batter were analyzed. Results showed that the potential absolute value increased when the EY was hydrolyzed by PLPA1. The distribution of yolk particle size showed a new aggregation and the average particle size decreased after LP hydrolysis. The dispersion samples hydrolyzed by PLPA1 and LP recovered all the properties of the samples at enzymatic concentrations of 500 U/g and 2500 U/g. This may be attributed to the changes in yolk particles resulting from the enzymatic digestion of EY and the production of amphiphilic lysophospholipids, fatty acids, and glycerol.

Effect of Soil Agricultural Use on Particle-Size Distribution in Young Glacial Landscape Slopes

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.

Fate Determination and Characterization of Food Additive Silicon Dioxide and Titanium Dioxide in Commercial Foods.

Silicon dioxide (SiO2) and titanium dioxide (TiO2) are ones of the most widely used food additives as an anti-caking and a coloring agent, respectively, in the food industry. Understanding particle, aggregate, or ionic fates of two additives in commercial products is of importance to predict their potential toxicity. Triton X-114 (TX-114)-based cloud point extraction (CPE) methods for two additives were optimized in food matrices. Their particle or ionic fates in various commercial foods were determined by the CPE, and the physico-chemical properties of separated particles were further characterized. SiO2 and TiO2 were primarily present as particle forms without changes in constituent particle size, size distribution, and crystalline phase. The maximum solubilities of SiO2 and TiO2 were 5.5% and 0.9%, respectively, depending on food matrix type, supporting their major particle fates in complex food matrices. These findings will provide basic information about the fates and safety aspects of SiO2 and TiO2 additives in commercial processed foods.

Influence of particle-size distribution on shear characteristics of slip zone soil and its mesoscopic mechanism

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.

Weak Expansive Soil Physical Properties Modification by Means of a Cement-Jute Fiber

Sixteen groups of comprehensive tests have been conducted to investigate the modifications in the physical properties of a weak expansive soil due to the addition of a cement jute fiber. The tests have been conducted to analyze the liquid plastic limit, the particle distribution and the free expansion rate. The results show that: (1) With an increase in the cement-jute fiber content, the free expansion rate of the modified expansive soil gradually decreases, however, such a rate rebounds when the fiber content exceeds 0.5% and the cement content exceeds 6%. (2) With an increase in the cement percentage, the particle unevenness coefficient (Cu) and curvature coeffi- cient (Cc) of the modified expansive soil tend to grow gradually. The Cc coefficient reaches 1.0 when the cement content is 6%. The unevenness coefficient of 16 soil samples is greater than 5.0, however, the Cu coefficient decreases when the cement content reaches 6%. (3) The plastic limit of soil increases as the cement content is made higher, while the liquid limit and plastic index decrease gradually. When the content of the modified material is 2% + 0.1%~2% + 0.7% (Cement content + jute fiber content), the change of particle size distribution is most obvious. (4) When the contents of cement and jute fiber are is 6% and 0.5%, respectively, the modification induced in the physical properties of soil samples corresponds to the best case.

Uticaj mehaničke aktivacije na smešu SrTiO3 i Fe2O3 kao aditiva

The authors investigated the influence of mechanical activation on the structure of SrTiO3 mixture with 6 wt.% Fe2O3. Powders were mechanically activated in a planetary ball mill with WC balls in time intervals from 0 to 120 minutes. XRD method was used for the identification of phase structure, while SEM and PSA were employed for monitoring of changes in morphology and particle size distribution. Structural changes were followed by Raman spectroscopy, and band gap values were calculated as well. The purpose of mechanical activation is lowering the temperature and time of sintering in the process of obtaining the final product.

Role of food matrix in modulating dairy fat induced changes in lipoprotein particle size distribution in a human intervention

BackgroundIntake of dairy fat within the matrix of cheese lowered circulating LDL cholesterol concentration to a greater extent than the same components consumed separately as butter, protein, and calcium. However, circulating LDL cholesterol is not indicative of concentration or size of LDL particles (LDL-P), which are recognized as more sensitive risk markers of CVD. ObjectivesThis was an exploratory analysis to investigate the role of the food matrix on lipoprotein particle size distribution, after a dairy fat intervention, in overweight adults aged ≥50 y. MethodsLipoprotein particle size distribution was measured in fasting EDTA blood samples taken at week 0 (baseline) and at week 6, using NMR. In total, 127 participants (BMI ≥ 25 kg/m2, aged ≥50 y) received ∼42 g dairy fat in 1 of 4 treatments: group A, 120 g full-fat cheddar cheese (FFCC); group B, reduced-fat cheese plus butter (RFC+B); group C, butter, calcium caseinate powder, and calcium supplement (CaCO3) (BCC); or group D, 120 g FFCC (as per group A) but after a 6-wk washout period during which they excluded cheese before intervention. ResultsTotal VLDL and chylomicron particles (VLDL/CM-P) decreased after intervention. There was a strong correlation between reduced VLDL/CM-P and a reduction in small proatherogenic VLDL-P (r = 0.888, P < 0.001). Reductions in total LDL-P were associated with a reduction in small LDL-P and, to a lesser extent, with large LDL-P. There was a significant main effect of treatment for change in intermediate-density lipoprotein particles (IDL-P) after the intervention (P = 0.023) between groups B and D (−46.86 ± 30.38 and 40.69 ± 32.72 nmol/L, respectively). HDL particle (HDL-P) parameters (diameter, concentration, or size distribution) were not affected by diet. ConclusionsOur findings indicate that reductions in LDL cholesterol observed with dairy fat consumption are driven by reductions in LDL-P concentration. A trend toward a less atherogenic profile was observed, but there was no clear effect of the individual food matrices.This trial was registered at ISRCTN as ISRCTN86731958.

Changes in Particle Size Distribution of Coal During its Transportation from the Face to the Mine Storage

Changes in Particle Size Distribution of Coal During its Transportation from the Face to the Mine Storage

Changes in raindrop properties due to wind blowing using image processing

The characteristics of raindrops are among the major factors influencing rainfall erosivity. However, the effect of wind blowing on the determining factors of raindrops was not adequately reported. This study aims to measure the characteristics of raindrops under concurrent simulation of rainfall and wind using image processing at different wind velocities under laboratory conditions. For this purpose, changes in particle size distribution, velocity, falling angle, and kinetic energy of raindrops under different wind velocities from 0 to 6 m.s−1 simultaneously simulated with a constant rainfall intensity of 50 mm h−1 were investigated through processing images taken using a high-speed camera. The results showed significant changes (P < 0.01) in the characteristics of the raindrop in the study wind velocities. By increasing wind velocity, the mean diameter and velocity of the raindrops increased and the falling angle of the raindrops on the soil surface decreased. The mean raindrop diameter, velocity, and the falling angle of the raindrops ranged from 0.93 to 2.17 mm, 3.45 to 7.30 m.s−1, and 32.04 to 89.83°, respectively, for different wind velocities. The mean kinetic energy for different wind velocities also exponentially ranged from 2.50 to 138.60 J. Eventually, external forces for different raindrops ranged from 2.47 to 137.65 mg.mm.s−1. These results would enhance scientific perceptions of splash and interrill erosions under the concurrent occurrence of rainfall and wind leading to better modeling of soil erosion processes.

Correlation analysis and application investigation of multi-angle simultaneous polarization measurement data and concentration of suspended particulate matter in the atmosphere

Determining the composition, particle size distribution and concentration changes of suspended particulate matter in the atmosphere is important for evaluating the quality of air and its impact on public health. The scattering and absorption of light by suspended particulate matter can change the polarization state of light, which can be used to extract characteristic information of measured particles. Firstly, we use our previously developed multi-angle simultaneous polarization measurement device to monitor the particulate matter around Dianshan Lake, Shanghai, and obtain high-throughput, high-dimensional Stokes data for nearly 1 month. The correlation between the Stokes data measured and the reference concentrations of five suspended particulate matter (Si, K, Fe, Ca, and Zn) was analyzed using the Periodical canonical correlation analysis (PCCA) method. The study shows a strong correlation between the three Stokes vectors and the concentrations of two types of suspended particulate matter in the atmosphere. Moreover, a prediction model for the concentration change of suspended particles was proposed by combining the locally weighted linear regression (LWLR) and the auto regressive moving average (ARMA) model. The prediction results on the concentration change of K and Fe in the atmosphere verified the validity of our method. The research in this work offers the possibility of continuous analysis and prediction of atmospheric suspended particulate matter in real environments.

Influence of 2‐hydroxypropyltrimethyl ammonium chloride chitosan on sedimentation and volume change behavior of cohesive soil sediments

AbstractThe 2‐hydroxypropyltrimethyl ammonium chloride chitosan (HACC), introducing the functional quaternary ammonium group to the structure of Chitosan, has greatly broadened the application prospect. The influence on natural cohesive soil has rarely been considered. The sedimentation tests for the natural soil in HACC solutions and the HACC‐treated soils in distilled water are considered to analyze the change of sedimentation behaviors in this paper. Moreover, the potential change on the surface of soil particles, the change in particle size distribution, X‐ray diffraction of Ca‐montmorillonite/HACC, and scanning electron microscopy images are investigated to explain the reasons for the results. Results indicate that the surface potential of soil particles achieved reversal, and the particle size had significant agglomeration. The adsorption of HACC results in the rapid sedimentation of the treated soils in water. HACC has a significant influence on setting time and final volume. HACC cannot inhibit the interlayer swelling of Ca‐montmorillonite. The dehydration process can promote the aggregation effect of the treated soils. The specific effects provided an essential train of thought to solve soil problems.

Multifractal characterization of gangue particle size distribution structure during ball milling process

This study is focused on the fractal characteristics of gangue particle size distribution(PSD) during ball milling process, taking mudstone, sandstone , and limestone gangue as the research object with multifractal theory, laser scattering-based particle size analysis , scanning electron microscopy (SEM), X-ray diffractometry (XRD) and other mesoscopic methods. The multifractal characteristic parameters of gangue PSD under different milling time and their correlation with the mesostructure are analyzed. The results show that the PSD of three gangues have different fractal characteristics and the multifractal parameters have stage distribution characteristics with time. The multifractal characteristic parameters of gangue, such as D(0) D (2), Δα 、 Δf , initially increase and then decrease with the increase of ball milling time, and reach the maximum value in 10-20 min. The heterogeneity of gangue PSD and the microscopic mechanism of multifractal parameter changes are revealed by examining the correlation between multifractal parameters and gangue morphology in fragmentation form. The change of gangue morphology is consistent with the change of multifractal parameters of PSD structure during ball milling process. • Particle size distribution multifractal characteristics of gangue have phased characteristics during ball milling. • Shape coefficient is highly consistent with the multifractal parameter of particle size distribution . • Particle breakage form is the main factor of particle size distribution and meso-structure change. • With an increase in milling time, the main forms of crushing transition from impact to extrusion and friction.

Two-stage valve homogenisation enhances particle dispersion in milk protein concentrates during reconstitution and reduces heat-induced particle aggregation in resultant dispersions

Milk protein concentrates (MPCs) are highly functional ingredients, with high-protein variants increasingly used in numerous applications. The objective of this study was to determine the impact of homogenisation, as part of the rehydration process, on solubility and heat stability of MPC. An 80% protein MPC powder was reconstituted (3% protein, w/v) and homogenised at 50°C using a pilot-scale, two-stage, valve homogeniser at different total pressures of 0, 5, 10, 15 and 20 MPa. Rehydrated samples were analysed for solubility, particle size, protein profile and heat stability (change in particle size distribution on heating in an oil bath at 140°C for 5 min). The results showed a considerable increase in solubility after applying homogenisation at 5 MPa. Homogenisation at pressures of 5–10 MPa reduced particle size of MPC dispersions further, with further increases in pressure having no additional effect. Increased heat stability was observed on increasing homogenisation pressures up to 10 MPa. This work demonstrates the positive impact of homogenisation on particle dispersion in MPCs and identifies a possible link between improved dispersion and heat stability. This would be applied as a strategy in dairy plants to reduce fouling in heat surfaces which suggests a significant economic impact in dairy processing.

Platinum Dissolution Induced Catalyst Layer Degradation in Polymer-Electrolyte Fuel Cells for Heavy-Duty-Vehicle Applications

Interest in electrifying the transportation sector has intensified as the value in reducing carbon emissions is recognized globally. Polymer-electrolyte fuel cells (PEFCs) provide an option for electrifying transportation if hydrogen is produced electrolytically from water and without carbon emissions if the electricity is provided by renewable energy resources. Though research in fuel cell powered vehicles has been ongoing, hydrogen infrastructure and concerns about hydrogen storage safety limit the technology’s uptake in the passenger vehicle market. However, fuel cells applied to heavy-duty-vehicle (HDV) transportation may address these shortcomings. HDV provide predictable routes allowing for more simple hydrogen infrastructure and larger cargo allowance in HDV allows for more secure hydrogen storage and safety. Fuel-cell-powered-HDV require higher operating temperature, pressure, and potential to realize the power-demands of the vehicle, therefore, durability requirements increase, and a better understanding of degradation is a priority. A major cause of performance degradation is due to catalyst dissolution, migration, and reprecipitation. This causes a loss of electrochemically active surface area (ECSA) which reduces the activity of the catalyst and is particularly detrimental in the cathode where the limiting factor for performance is often sluggish oxygen reduction kinetics. This loss in ECSA is due to an overall broadening of the particle size distribution (PSD) within the catalyst layer and a net loss of catalyst to the formation of a Pt band in the membrane. In this work, a Pt catalyst degradation model is developed which considers particle size dependent Pt oxidation and dissolution kinetics, Pt migration, and reprecipitation of Pt within the cell. This work interrogates the particle size dependence of these processes to explain experimentally observed loss in ECSA and changes in PSD. The degradation model is coupled with a PEFC performance model through the ECSA loss to study how the HDV-relevant operating conditions impact the cathode catalyst degradation behavior observed in PEFCs.

Ammonia Decomposition over Ru/SiO2 Catalysts

Ammonia decomposition is a key step in hydrogen production and is considered a promising practical intercontinental hydrogen carrier. In this study, 1 wt.% Ru/SiO2 catalysts were prepared via wet impregnation and subjected to calcination in air at different temperatures to control the particle size of Ru. Furthermore, silica supports with different surface areas were prepared after calcination at different temperatures and utilized to support a change in the Ru particle size distribution of Ru/SiO2. N2 physisorption and transmission electron microscopy were used to probe the textural properties and Ru particle size distribution of the catalysts, respectively. These results show that the Ru/SiO2 catalyst with a high-surface area achieved the highest ammonia conversion among catalysts at 400 °C. Notably, this is closely related to the Ru particle sizes ranging between 5 and 6 nm, which supports the notion that ammonia decomposition is a structure-sensitive reaction.