Particle Size Distribution In Range Research Articles

Nanobubble-Assisted Flotation of Apatite Tailings: Insights on Beneficiation Options.

Processing of materials that originated from tailings of industrial plants (with a wide range of particle size distribution, “PSD”) without grinding has several advantages since mines are faced with a lot of pressure to minimize their environmental impacts. This article indicates that the introduction of submicron bubbles (known as nanobubbles, “NBs”) to conventional flotation could improve the separation efficiency of valuable minerals from their associated gangue phases. It was demonstrated that metallurgical responses (recovery, grade, selectivity, and kinetics) of NB flotation could improve compared to those of conventional tests. Various hydrodynamic cavitation setups for NB generation may lead to different metallurgical responses. In general, the addition of surfactants (frothers and collectors) for NB generation could increase both mass and water recoveries, which would be key factors on selectivity. Selectivity is also markedly dependent on the PSD of feed, and the selectivity of NB flotation is improved significantly by decreasing the feed size. In general, generation of NBs in the presence of a frother leads to higher flotation metallurgical responses than in the presence of a collector.

Understanding implications of cathode architecture on energy density of solid-state batteries

Next generation solid-state batteries (SSB) will need to leverage high voltage cathodes, as well as metallic anodes to achieve the realistic performance targets necessary to replace liquid electrolyte-based batteries in cutting-edge applications including electric vehicles. However, limitations arising from mass and charge transports, kinetics and chemo-mechanical degradation at the electrode | electrolyte interface limit the performance of present day SSBs. Optimizing composite cathode architecture, which is an integral part of solid-state batteries, is vital to realize the high-energy density and high-performance goals for next-generation solid-state batteries. Cathode architecture needs to be optimized for high loadings of active material, well-percolated ion and electron transport pathways and increased resilience against electrochemical stresses. This paper provides a first report of framework for geometric modeling of composite cathode architectures and evaluates the impact of cathode architecture on cell-level energy density using hierarchical models. Packing around primary and secondary active material particles are simulated for a range of active material particle size and solid electrolyte size distributions in the composite cathode. Impact of packing architecture on processing parameters of a given cathode composition and thickness, as well as on achievable energy density is evaluated for a range of commonly used solid electrolyte and cathode materials. Overall, the proposed framework offers a facile exploratory methodology for establishing initial metrics for scalable processing of practical and competent SSBs.

Ultrasound Imaging and Antithrombotic Effects of PLA-Combined Fe3O4-GO-ASA Multifunctional Nanobubbles.

PLA-combined ferroferric oxide–graphene oxide–aspirin (Fe3O4-GO-ASA) multifunctional nanobubbles were prepared using the double emulsion-solvent evaporation method. The obtained composite nanobubbles had a regular spherical shape, Zeta potential of (−36.5 ± 10.0) mV, and particle size distribution range of 200–700 nm. The experimental results showed that PLA-combined Fe3O4-GO-ASA nanobubbles could effectively improve the antithrombin parameters of PT, TT, APTT, and INR, and significantly inhibit thrombosis when the composite nanobubbles with a concentration of 80 mg·mL−1 interacted with the rabbit blood. The prepared composite nanobubbles could reach a significant ultrasonic imaging effect and good magnetic targeting under the magnetic field when the nanobubbles' concentration was only 60 mg·mL−1.

Implication of Non-Uniform Anode Particle Morphology on Lithium-Ion Cell Performance

The present works deals with the implications of non-uniform anode particle morphology on charging and discharging characteristics of Lithium-ion cell, especially for ultra-fast charging applications. The one-dimensional isothermal model is employed to analyze the effect of C-rate, porosity, tortuosity, and particle geometry for a range of non-uniform anode particle size distribution numerically. Our study reports that the value of capacity and specific power of the cell is found to be maximum when the particle size decreases along the electrode length. In contrast, capacity and specific power are minimum when anode particle size increase along the anode length. Moreover, a significant improvement in the performance of the Lithium-ion battery is found at ultra-fast charging when non-uniform particle distribution is employed. Additionally, a strong interplay of particle distribution and microstructural attributes viz. porosity and tortuosity on cell performance are revealed for the charging-discharging cycle. Further, the capacity of the cell is found to be maximum when the particle geometry is spherical. We anticipate that the results can inspire further improvement in ionic transport for ultrafast charging with non-uniform microstructure in the Li-ion cell.

Modelling the fluidised bed in HydroFloat™ for improved process control

This study investigates the expansion of the fluidised bed in HydroFloat™ as the teeter water velocity is varied. A practical model is presented for predicting the fluidised bed porosity and apparent density at set cell operating conditions (teeter water flow rate, air flow rate, bed height, pressure setting) and feed ore characteristics (specific gravity and particle size). Inversely, the model can be used to calculate the optimum HydroFloat™ settings to obtain the desired fluidised-bed porosity, for any ore of interest. The model is based on the well-known approach by Richardson and Zaki, modified by introducing more suitable settling rate equation within the typical particle size (and Reynolds numbers) range encountered in Hydrofloat™, and also considering the effect of air input. The model has been validated using two different copper ores in a range of feed particle size distributions, showing good predictive capabilities.

Fractal and multifractal analysis of soil particle-size distribution and correlation with soil hydrological properties in active layer of Qinghai–Tibet Plateau, China

The soil hydrological properties (HPs) in active layers regulate soil water migration and affect the evolution of permafrost and biogeochemical cycles. There is relatively little understanding of the changes in soil HPs as a result of soil particle-size distribution (PSD) in the permafrost regions of the Qinghai–Tibet Plateau. In this study, different land-cover types, namely alpine wet meadow (AWM), extremely degraded wet meadow (EDWM), alpine meadow (AM), degraded alpine meadow (DAM), alpine steppe (AS), and alpine desert (AD), were used to determine the relationships between soil PSD and HPs. Soil HPs were determined using borehole nuclear magnetic resonance, and soil PSD (0–2 mm) was analyzed using fractal and multifractal theory. The results showed that vegetation degradation caused coarse soil particle accumulation in the root zone, reflected by the soil single-fractal dimension (Dv: 2.12–2.50). The Dv values showed significant positive correlations with soil clay and silt content as well as a negative correlation with sand content. Results from the generalized fractal and singularity spectra suggested an even distribution of soil particles in the root zone of the AWM, AM, and AD sites. Vegetation degradation increased the soil PSD capacity dimension (D0), information dimension (D1), correlation dimension, D1/D0 ratio, and Hölder exponent of order zero. This was indicative of a narrow soil PSD range and non-uniform soil texture in the root zone. Although capillary water dominated the total soil water content in the alpine soils, soil water composition was also dependent on the vegetation type and soil stratigraphic distribution. Soil particle composition and multifractal dimensions were found to be effective parameters for forecasting soil HPs in the non-root zone of alpine soils. However, the presence of vegetation weakens the relationship between soil PSD and HPs. This study contributes to the accurate evaluation of hydrological and biogeochemical cycles in permafrost regions.

Cleaner way for overall water splitting reaction by using palladium and cobalt based nanocomposites prepared from mixed metallosurfactants

Exploring the electrocatalyst prepared by novel methodology is highly demanding for overall water splitting reaction. Herein, we have developed a Palladium and Cobalt based (PdCo) nanocomposite that serves as a dual active electrocatalyst for both hydrogen evolution reaction (HER) (0.5 M H2SO4, 1 M KOH) and oxygen evolution reaction (OER) (1 M KOH). The present nanocomposite is synthesised via reduction of reverse mixed metallomicellar core formed using palladium and cobalt metallosurfactants. The main approach of this methodology is to control the size of nanoparticle within the core of the metallomicelle with smaller and limited range of particle size distribution. This approach is cost effective and has reduced reaction time. The present electrocatalyst require 78 mV, and 310 mV of overpotential to achieve 10 mA cm−2 of current density for HER (acidic) and OER (basic), respectively. This study provides a new methodology for the development of a new generation electrocatalyst.

Critical quality attribute assessment of big brand traditional Chinese medicine: process quality control method of Suhuang Zhike Capsules intermediate based on physical properties of powder and granules

The physical properties of powder and granules are the critical quality attributes for the process control of Suhuang Zhike Capsules, a big brand traditional Chinese medicine. This paper took the production of 25 batches of real-world Suhuang Zhike Capsules dry extract powder and granules intermediates as the research object. Firstly, a method for testing the physical properties of Suhuang Zhike Capsules powder and granules with 19 physical indicators was established. The results showed that the granules of dry extract powder after granulation had a smaller particle size, wider particle size distribution range and poor fluidity, which easily caused the problem of over-limit capsule loading. Secondly, correlation analysis, principal component analysis and cluster analysis were used for mathematical statistics. The correlation analysis showed that the density of dry extract powder could affect the chroma and fluidity. At the same time, the particle size in the granules had a stronger effect on the chroma and fluidity than the density. The study also found that the particle size and hygroscopicity of dry extract powder were potentially key physical properties that affected the physical properties of granules. Furthermore, the results of principal component analysis and cluster analysis showed that the consistency of the physical properties between the dry extract powder and intermediate granules was relatively poor. To this end, similarity analysis was carried out, and the quality control method of powder and granules based on physical fingerprint was established. The results showed that the physical fingerprint similarity of 25 batches of dry extract powder was 0.639-0.976, and the physical fingerprint similarity of the gra-nules was 0.716-0.983. With the similarity of 0.85 as the threshold, the batches with abnormal physical properties could be identified. In this study, the process quality control method of Suhuang Zhike Capsules based on the physical properties of powder and granules was established finally, which realized the identification of abnormal batches, and provided a reference for the process quality control of Suhuang Zhike Capsules.

Experimental Research on Atomization Parameters of High Pressure Nozzle

The effect of wind speed on the nozzle effective water volume and distribution uniformity and the fog particle size was studied. The results showed that when the fog particle size and the dust particle size distribution range were close, the dust reduction effect was the best. With the increase of spray pressure, Under the influence of the wind flow, the effective water flow of the nozzle is 80% of the effective water without wind flow, as the wind speed increases, the spray range and the spray coverage area decrease greatly. about. Based on the experimental results, the dust-reducing efficiencies of total dust and respirable dust concentration were 91.1% and 90%, respectively, after the dust was sprayed by the preferred nozzle at the unloading point of the Xiadian Gold Mine unloading station.

A gradation-dependent particle shape factor for characterizing small-strain shear modulus of sand-gravel mixtures

In this study, a series of shear wave velocity tests were conducted on two types of sand-gravel mixtures with a wide range of particle size distributions. The effect of the particle shape on the small-strain shear modulus (Gmax) was investigated using a customized, large-scale triaxial apparatus. The results showed that Gmax increases with the decrease in particle roundness when the uniformity coefficient (Cu) is less than a certain value. However, this increasing trend gradually flattens with the further increase of Cu. Thus, the effect of particle shape on the Gmax varies with the particle gradation. The performances of six relationships proposed in the literature for predicting Gmax were compared and evaluated in terms of their predictive capabilities. An empirical Gmax model based on the Hardin and Black equation was proposed by including a Fourier-based shape factor modified by Cu. The model can characterize the difference in the variation of Gmax with Cu due to different particle shapes and was thereafter validated. Furthermore, the model serves as a reference guide for estimating the Gmax of soils with various particle size distributions through their particle characteristics.

Lidar observation of aerosol transformation in the atmospheric boundary layer above the Baltic Sea

Investigation results of a coarse and accumulation mode of aerosol properties above the Baltic Sea are reported. A most important role in the direct aerosol effect on climate have aerosols from the group of coarse and accumulation mode particles. Overseas in the atmosphere, there is a lot of aerosols from the fine fraction but their impact is not so important as coarse and accumulation mode particles. Sea spray emission from the sea surface takes place over a wide range of aerosol particle size distribution, it is also large in size range which are studying in this work (Lewis and Schwartz, 2004). The discussed range is most important in view of atmospheric optical properties, smaller particles do not have such an influence on scattering as particles from range 0.5–2 µm. The research was performed with a multiwavelength lidar. Due to the application of special software, the aerosol particle size distributions were retrieved from the lidar returns. That provided an opportunity to determine the profiles of the aerosol effective radius. We showed that the aerosol properties depend mainly on the direction of the air mass advection and the wind speed. The impact of the Baltic Sea on the aerosol size distribution is huge in the case of the advection from the open sea. Moreover, the aerosol effective radiuses in the whole boundary layer are much larger in the case of strong than for light wind. Our results suggest that the aerosol flux and the aerosol particle size distribution should be related to the wind speed in the emission function.

Influence of carbon dot synthetic parameters on photophysical and biological properties.

Recently, carbon dots (CDs) have been widely investigated for biological applications in imaging. One-step hydrothermal synthesis is considered to be one of the most promising methods for the synthesis of CDs, due to its simple and rapid manipulation, flexible selection of ingredients, environmentally friendly conditions, and low-cost. A number of synthetic and post-synthetic parameters, including solvent, heating time, dopant quantity, and particle size distribution, play a crucial role in controlling the size and surface structure of CDs, which ultimately have influence on their photophysical and biological behavior. Despite the crucial role of each of these parameters in defining the yield and nature of synthesized CDs, they have not previously been rigorously optimized, particularly with respect to desired biological applications. Herein, we report our comprehensive optimization of the parameters employed for the hydrothermal synthesis of CDs to gain a better understanding of the effect of these parameters on optical properties, cytotoxicity, and cellular uptake efficiency. Furthermore, this work will open up new pathways toward the design of CDs with physiochemical properties tailored for specific biomedical applications such as bioimaging.

Winter Pollution Characteristics and Physicochemical Properties of PM2.5 in a Northwest Industrial City

To study winter pollution characteristics and physicochemical properties of PM2.5 in a northwest industrial city, for example, Baiyin in Gansu Province, we used related instruments, such as single particle aerosol mass spectrometry to conduct real-time online PM2.5 chemical composition observations, compared with Lanzhou in the same period. The results showed that, during the observation, PM2.5 concentrations (44.89 μg·m-3) in Baiyin were significantly lower than the same period in Lanzhou (70.69 μg·m-3). However, the proportion of particles containing heavy metals (7.84%) was significantly higher than that of Lanzhou (2.92%), the chemical composition was complex, and PM2.5 was mainly contributed by particles with larger particle sizes. The particle size distribution range of Cu, Pb, and Zn particles in Baiyin was relatively wide, the number of Cu and Zn particles was higher, and the mixing ratio of particles was higher than in Lanzhou. The main pollution source was automobile exhaust 30.91% and a secondary inorganic source was 13.00%. The pollution event on January 4, 2020 was mainly caused by the increased contributions of automobile exhaust and secondary inorganic sources, and the poor meteorological diffusion conditions in the early stage. The control of PM2.5 pollution in Baiyin in winter should be dominated by emission reduction of automobile exhaust and secondary inorganic sources, and control of heavy metal pollution in the atmosphere should be strengthened.

Experimental study on sand particles accumulation, migration and separation efficiency in slug catcher

Sand production often leads to the failure of production equipment on offshore platform. Therefore, a new idea has been put forward, which is installing cyclone or baffle in the internal of the slug catcher for better sand control. In this paper, an experimental study is presented, which mainly includes sand particles accumulation shape, migration law and separation performance. The results suggest that the accumulation area is mainly divided into two zones: the crowded settlement zone and the free settlement zone. The crowded settlement zone has a special shape, which can be characterized by two parameters: accumulation length and accumulation angle. Axial sampling analysis shows obvious particle classification. Median particle size decreases with the increase of the axial distance, and the range of particle size distribution narrows gradually. The separation experiment shows that the gas velocity has the greatest influence on the separation efficiency. When the gas velocity is 14 m⋅s−1, the separation efficiency drops sharply, which can be abated by installing cyclone separator. In addition, the separation efficiency tends to be a constant under different gas velocities by installing baffle with appropriate height. Then the effectiveness and rationality of installing internal components can be strongly proved. All these provide important guidance for maximizing the sand control function of the slug catcher.

Facile fabrication of vanadium sensitized silver titanium oxides (V–Ag/TiO2) photocatalyst nanocomposite for pollutants removal in river water

Vanadium sensitized silver titanium mixed metal (V–Ag/TiO2) oxides photocatalyst nanocomposite was prepared by a sol-gel, hydrothermal route. Lattice fringes for both anatase and rutile in its crystalline phase was depicted by X-Ray Diffraction (XRD) structural analysis. Surface areas (SBET) analysis shows that synthesized V–Ag/TiO2 has a huge surface area of 74.58 m2g-1, compare to TiO2 94.77 m2g-1, Ag–TiO2 89.32 m2g-1 and V–TiO2 82.59 m2g-1. Optical absorption results demonstrated by UV–Visible Spectroscopy (UV–Vis) shows a reduced bandgap energy of 2.3 eV and a shift in spectrum to the visible light region, enhancing the visible light absorption capacity of the synthesized photocatalyst. Binding energies of species were presented by X-ray photoelectron spectroscopy (XPS). Scanning electron microscope (SEM) image shows the formation of a closely stacked cluster composed of rod-like aggregated particles of non-uniform diameter while Transition Electron Microscope (TEM) shows particle size distribution range between 15 and 25 nm. Synthesized V–Ag/TiO2 showed tremendous photocatalytic abilities under visible light irradiation as gas chromatography–mass spectrometry (GC–MS) analysis of surface water from Lepelle River Limpopo province of South Africa demonstrate the selective removal of organic pollutant.

Predicting the small strain shear modulus of coarse-grained soils

Coarse-grained soils are important geotechnical materials widely used in construction. The contribution of particle size distribution on the small strain shear modulus Gmax of coarse-grained soils has not yet been fully recognized. This paper presents an experimental investigation into the effects of the uniformity coefficient Cu and the mean particle size D50 on the small strain shear modulus of coarse-grained soils. To this end, a series of shear wave velocity tests were conducted at different confining stresses and void ratios on reconstituted specimens covering a wide range of particle size distributions. All tests were performed by taking advantage of a custom-developed measurement device in a large-scale triaxial apparatus. The results demonstrate that Cu and D50 have pronounced but opposite effects on Gmax. Specifically, Gmax decreases with Cu and increases with D50. The effects of Cu and D50 were then quantified to generate two types of empirical equations, type-A and type-B, that are representative of a broad family of Gmax equations accounting for the influence of particle size distribution. The equations are tuned based on model parameters A, x and n. In both equations, n is a function of Cu. The difference between the two types of equations is that x is the function of Cu and D50 and A is the function of Cu in the type-A equation, while x is constant and A is the function of Cu and D50 in the type-B equation. The proposed equations for predicting Gmax were used to produce acceptable estimates for both coarse-grained soils in this study and from existing literature. The findings acquired from this study are expected to provide a reference for estimating the small strain shear modulus of coarse-grained soils at the beginning of the project when the test data have not yet been obtained.

Particle-Scale Simulation of Solid Mixing Characteristics of Binary Particles in a Bubbling Fluidized Bed

The behavior of solid mixing dynamic is of profound significance to the heat transfer and reaction efficiencies in energy engineering. In the current study, the solid mixing characteristics of binary particles in the bubbling fluidized bed are further revealed at particle-scale. Specifically, the influences of gas superficial velocity, Sauter mean diameter (SMD) in the system and the range distribution of particle sizes on the performance of mixing index are quantitatively explored using a computational fluid dynamics-discrete element method (CFD-DEM) coupling model. The competition between solid segregation and the mixing of binary particles is deeply analyzed. There is a critical superficial velocity that maximizes the mixing index of the binary mixture in the bubbling fluidized bed. Solid mixing performs more aggressive when below the critical velocity, otherwise solid segregation overtakes mixing when above this critical velocity. Moreover, superficial velocity is a major factor affecting the mixing efficiency in the binary bubbling fluidized bed. Additionally, the mixing behavior is enhanced with the decrease of SMD while it is deteriorated in the binary system with a wide range of particle size distribution. Therefore, it is highly recommended to perform a binary particle system with smaller SMD and closer particle size distribution for the purpose of enhancing the mixing behavior. The significant understanding of mixing characteristics is expected to provide valuable references for the design, operation, and scale-up of binary bubbling fluidized bed.

Developing conceptual and empirical models for well- and gap-graded soil particle size distribution (PSD) curve

ABSTRACT Most of the previously introduced soil particle size distribution (PSD) models have at least one limitation. To overcome the limitations of the PSD models, two conceptual soil PSD models (unimodal- and bimodal-exponential), and one empirical model were suggested to represent PSD curve and evaluated based on the root mean square error (RMSE), adjusted coefficient of determination (R 2 adjusted), coefficient of determination (R 2), and corrected Akaike’s information criterion (AICc). The RMSE, R 2 adjusted and AICc were 0.068, 0.969, and −29.6; 0.073, 0.955 and −3.5; and 0.102, 0.905, and −13.9 for unimodal-exponential, bimodal-exponential and empirical models, respectively. Therefore, the unimodal and bimodal-exponential models were flexible over the entire range of soil PSD. The results were compared with those of 35 PSD models investigated in the previous studies. The results showed the superiority of the conceptual models and only eight percent of the models had an accuracy similar to the conceptual models. Therefore, fewer parameters (three, five and two parameters for unimodal-exponential, bimodal-exponential and empirical models, respectively), easy fitting procedure and high accuracy in terms of R2 adjusted, RMSE and AICc criteria are considered as the most important advantages of the proposed models to describe the soil PSD from 0 to 0.002 m.

Hydrodynamic studies in two - phase stirred fluidized bed with three types of impellers

Fluidized beds are extensively used in petrochemical, chemical process industries, pharmaceutical, food and biotechnology industries. They are preferred to process materials with a wide range of particle size distribution and offer even temperature distribution and excellent heat and mass transfer. To improve the quality of the fluidized bed, mechanical stirring can be employed along with aeration. Hence, an attempt was made to study the hydrodynamics of stirred fluidized bed using air-water system. The characteristics of the fluidized bed can be well understood by studying its hydrodynamics. Pressure drop is one of the vital factors which affect the performance of fluidized bed. Hence, the effects of gas velocity and stirrer speed on pressure drop and power were studied for both stirred and unstirred bed conditions. It was observed that pressure drop and power increases with increase in gas velocity and stirrer speed. Also, the pressure drop and power are lower for the stirred bed condition than the unstirred bed condition.

Continuous Operation on Synthesis and Surface Modification of Rutile Nanoparticles in Designed Microfluidic Reactors.

Synthesis and surface modification of rutile nanoparticles (NPs) are two distinct processes. Conventionally, they should be conducted separately. In this work, synthesis and surface modification of rutile NPs are consecutively performed in a designed microfluidic system, thereby avoiding the pilot processes, giving a high controllability and low-energy consumption of the process, and the preparation process of the coated TiO2 is simplified effectively. Samples synthesized using different strategies are compared, and the results demonstrate that the sample prepared using the microfluidic method shows a smaller particle size (60 nm) and a narrower particle size distribution range than those synthesized using the other two methods. Rutile NPs are most commonly used in terms of suspensions, the stability of the suspensions consisting of the naked and coated samples are assessed in terms of turbidity, agglomeration size, and settlement rate. Response surface methodology is employed to quantify the effects of the factors on the stability of suspensions.