Particle Diameter Research Articles

Prediction of Progressive Erosion Characteristics of Centrifugal Pump Blades Based on Dynamic Boundaries

Abstract The conventional method of fixed boundaries for predicting erosion inadequately reflects the erosion characteristics of centrifugal pumps under realistic operating conditions. In this research, we employ the dynamic boundary method, considering the influence of changes in wall morphology due to erosion on the flow field. We utilize the Euler-Lagrange approach and the E/CRC erosion model, incorporating a dynamic boundary geometry reconstruction strategy, to predict the erosion characteristics of the IS80-50-315 single-stage single-suction centrifugal pump. Solid-liquid two-phase flow calculations are conducted on the pump to predict erosion characteristics under varied operating conditions. The results show that the dynamic boundary-based progressive erosion prediction method realistically forecasts the erosion characteristics of the overflow wall and captures the evolution of blade morphology with erosion time. Erosion intensity on the blade suction surface significantly surpasses that on the pressure surface, guided by particle distribution characteristics in the centrifugal pump flow channel. Particle diameter primarily influences the erosion position of centrifugal pump blades; smaller particles induce erosion in the middle region of the blade, while an increase in particle diameter shifts the severe erosion position towards the impeller outlet direction. At a consistent particle diameter, higher particle concentrations correspond to elevated erosion rates in the blade area. We establish a relationship between the blade mass loss rate and erosion time during 2500 hours of pump operation at the design condition, introducing the blade mass loss rate for convenient assessment and prediction of blade damage in the centrifugal pump.

Development and evaluation of novel taste-masking tilmicosin microcapsules containing octenylsuccinic anhydride modified starch and maltodextrin as wall materials

Tilmicosin (TMS) is an important antibiotic in veterinary medicine, but its extreme bitter taste limits its use. In this study, TMS was encapsulated in octenyl succinic anhydride modified starch/maltodextrin (HI-CAP/MD) composite capsules with a spray drying method. The TMS microcapsules (TMS-MC) exhibited good drug loading performance with drug loading (DL) and encapsulation efficiency (EE) of 9.90 ± 0.23 % and 98.03 ± 1.56 %, respectively. There was no significant change in particle diameter and zeta potential for the emulsion and redissolved TMS-MC. These results combined with FT-IR, TGA and DSC showed the crystalline shape and chemical structure of TMS did not change during the microencapsulation. In vitro release characterization in an acidic medium (pH 1.2) and an alkaline medium (phosphate buffered solution, pH 6.8) showed that TMS-MC can be rapidly released in vitro. The bitterness evaluation implied the bitterness of TMS was masked after microencapsulation. In vitro bacterial inhibition test showed the bacterial inhibitory activity of TMS was not reduced by the microencapsulation, but was much better than that of the commercially available tylosin (TLS). Therefore, HI-CAP/MD can effectively encapsulate TMS, mask the bitter taste and maintain a good bacterial inhibitory effect, making a new drug formulation with good development prospects.

Numerical simulation of multiphase flow induced by bottom blowing limestone powder in converter steelmaking

A full-scale three-dimensional model of a 120 t steel converter was established to evaluate the effects of bottom-blown limestone particle injection speed, diameter, and nozzle location on the particle distribution and molten metal flow field using numerical simulations. The results indicated that a particle injection speed of 6 m/s, particle diameter of 0.5 mm, and injection nozzle location at 1/2 of the converter bottom radius provided the longest particle residence time and largest quantity of particles in the molten metal. Furthermore, the use of these parameters produced within the molten metal an obvious particle concentration along the centerline of the converter, the fastest average liquid metal–particle flow velocity, and moderate splashing. These optimal injection parameters created favorable kinetic conditions for the dephosphorization reaction essential to steelmaking. This study provide a theoretical basis for realizing the improved efficiency associated with the use limestone instead of lime in practical steel production.

Optimization of Tantalite Ore Dissolution Using Hydrofluoric-sulphuric Acid and Shrinking Core Model

Aim: This study investigates the dissolution of tantalite mineral from granitic pegmatite in Okpella, Northern Edo State, Nigeria. Study Design: Elemental and mineral composition analysis of tantalite ore sample from Okpella was carried out using X-ray fluorescence and X-ray diffraction. Response Surface Methodology (RSM) and the shrinking core model were used in designing the study while the effects of temperature, stirring speed, particle diameter, and mixed acids concentrations were investigated in the dissolution rates of the mineral. Duration of Study: 50 experimental runs were designed using RSM Central Composite Design (CCD) to optimize variables including HF concentration (1-8 M), H2SO4 concentration (0.5-3 M), temperature (32-82°C), stirring speed (0-500 rpm), and particle size (0.1-0.3 mm), with a constant contact time of 240 minutes. Methodology: Pulverized tantalite samples (0.1-0.3 mm) were reacted with varying concentrations of hydrofluoric and sulphuric acids (1-8 M and 0.5-3.0 M, respectively) for 240 minutes, with stirring speeds between 0-500 rpm and temperatures from 32 to 82°C. The mixture was stirred in a water bath with 50 ml of mixed acids solution and 2 g of ore. After the reaction, the solution was decanted, and the residual ore was washed, dried at 60 °C, and weighed. The difference between the initial and final weights indicated the amount of undissolved tantalite ore. Results: Ore characterization results revealed high concentration of tantalum (34.17%), iron (12.55%), niobium (8.38%), and titanium (6.01%), with other elements present in smaller amounts. Optimal conditions were found to be 8 M HF, 0.5 M H2SO4, 82°C, 500 rpm stirring speed, and 0.1 mm particle size, resulting in 97.28% dissolution of tantalite ore. Regression analysis demonstrated model robustness with an F-value of 16.70 and a P-value of 0.0001, indicating HF concentration and stirring speed as the most impactful factors. The model’s R² value of 0.9201 and adjusted R² of 0.8650 confirm its predictive accuracy. Analysis using the shrinking sphere model showed that film diffusion control is the primary limiting step with t/τ=0.999, while reaction control resulted in slightly lower conversion with t/τ=0.973, highlighting film diffusion as the main constraint but with high conversion efficiency. Conclusion: The findings from this investigation not only reveal the dissolution of tantalite ore through a detailed experimental approach, identifying optimal conditions -8 M HF, 0.5 M H2SO4, 82 oC, 500 rpm stirring speed and 0.1 mm particle size- that achieve a 97.28% dissolution, but they also enhance our understanding of mineral processing. These understanding are crucial for mineral dissolution up scaling technologies in industrial applications, which will potentially leads to a more efficient extraction method that could significantly reduce costs and environmental impacts in the mining sector. This research could drive advancements in sustainable resource recovery and contribute to sourcing of critical minerals.

Water Turbine Guide Blades Effect of Quartz Sand on Abrasion Rate

Abstract Hydroelectric power plants with the aim of being used to generate electrical energy are mostly operated in areas with sedimentation content which can cause wear and tear on the components of the hydropower plant. This activity is emphasized to determine the effect of quartz sand on the rate of abrasion on the guide vanes of the Francis type water turbine. This activity was carried out using a water turbine guide blade abrasion test tool with a guide blade test object made of SUS 304 stainless steel material. The results are presented quantitatively and qualitatively, the greater the concentration and diameter of the quartz sand particles, the water pressure and the angle given at the same time, the greater the rate of abrasion that occurs in the francis type water turbine guide vane. The highest abrasion rate was 5.10 (g/cm2 x hour) in the angle variation test with a constant Q and a water: sand ratio of 70%: 30%.

Enzyme-assisted hydrolysis of Theobroma cacao L. pulp

Cocoa pulp, a by-product of the cocoa supply chain, has gained the food sector’s attention for its pleasant flavour. Enzyme-assisted technologies to facilitate its separation from the cocoa seeds remain largely unexplored. We studied the effects of temperature, enzyme activity and enzyme combinations on the physicochemical properties of cocoa pulp by Response Surface Methodology and D-optimal design. Endo-polygalacturonase, endo-cellulase and hemicellulase activities were investigated. A reduced quadratic model described the relative reduction in viscosity, of the particle diameter dv,0.9 and of the browning index. Polygalacturonase had the strongest influence on viscosity, while cellulase had the least effect. Synergistic effects of polygalacturonase with cellulase and/or hemicellulase were identified. The model predicted maximal reductions in viscosity by 70.3% with 275 U of polygalacturonase and 275 U of hemicellulase at 40 °C. Fresh pulp’s dv,0.9 was 613 μm. Combining all enzyme activities reduced the dv,0.9 to 418 μm (40 °C, total activity: 580 U). Only the temperature proved to significantly influence the browning index, with higher temperatures causing a higher colouring effect. Lastly, the model was successfully validated for the relative reduction in viscosity and the dv,0.9. Our study provides key insights into the enzyme-assisted processing of cocoa pulp, facilitating its separation from the seeds. By utilising the pulp, innovative ingredients can be developed for the food sector, and at the same time, the added value in the cocoa supply chain can be improved.

Influence of flame stability on iron oxide nanoparticle growth during FSP

Flame stability during flame spray pyrolysis (FSP) remains an active topic of investigation due to its impact on synthesised particle attributes and purity. The unique feature of the burner investigated here is the ability to control flame stability over newly defined stability maps. The novelty of the current work lies in understanding the influence of these broad stability modes on nanoparticle growth during FSP and on the attributes of collected products. Several distinct flame configurations are selected for iron oxide nanoparticle synthesis, ranging from stable to highly unstable flames. The flame stability regimes are characterised by OH∗ chemiluminescence and broadband flame luminescence imaging. Stability is correlated with the coefficient of variation of flame luminescence (CV) and flame height with mean OH∗ chemiluminescence. Planar Mie scattering is then used to identify the effect of flame luminescence intermittency on spray atomisation and evaporation quality. For particle analysis, in-situ thermophoretic sampling is performed from 30 to 200 mm above the burner exit plane and analysed via transmission electron microscopy (TEM). Further ex-situ analysis is also performed on the bulk-collected product via high-resolution TEM, X-ray powder diffraction (XRD), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). It is demonstrated that flames with higher instability (CVmin ≥ 0.35) maintain increased spray heights (>26 %) and reduced flame heights (>79 %) compared to stable flames with the same precursor volume flowrate. This reduces the high-temperature particle residence time for primary particle growth and impacts subsequent agglomeration. For example, the mean diameter of gyration and primary particle diameter are found to vary by 44 % and 29 % depending on the flame regime, respectively. Ex-situ analysis also demonstrates that the dominant iron oxide phase produced is maghemite regardless of the stability regime. However, higher concentrations of organic impurities including methyl, methylene and carboxylate functional groups are found via ATR-FTIR with increased flame instability (CV).

Particle size by design: Standardizing measurements for complex topical drug product assessment

The physicochemical and biopharmaceutical properties of drug substances and dosage forms can be significantly influenced by particle size. However, the diversity of equivalent particle diameters generated by different methods poses a fundamental challenge in particle size analysis. This study aimed to develop an Analytical Quality by Design (AQbD) approach to accurately assess the particle size of a complex formulation – clobetasol propionate (CP) 0.5 mg/g cream – through automated microscopy (AM) and laser light diffraction (LD). Additionally, Raman spectroscopy was utilized to determine the chemical composition of the formulation particles. In the AQbD approach, prior knowledge was considered for the construction of the Ishikawa diagram and estimate failure mode and effects analysis (FMEA). The methods were developed following the ICH Q8-Q10, and ICH Q14 guidelines, and validated according to ICH Q2, ISO 13320:2020, and EP2.9.31./USP<429>. Results indicate that a trade-off between the techniques must be established for a particle size by design: while LD offers higher throughput and more precise values at the expense of peak resolution and broadening, AM has higher variability but more reliable information in terms of size and shape analysis. The validated methods successfully demonstrated the implementation of an AQbD method in the definition of particle size methods.

Numerical modeling of particle deposition in a realistic respiratory airway using CFD-DPM and genetic algorithm.

In this study, a realistic model of the respiratory tract obtained from CT medical images was used to solve the flow field and particle motion using the Eulerian-Lagrangian approach to obtain the maximum particle deposition in the bronchial tree for the main purpose of optimizing the performance of drug delivery devices. The effects of different parameters, including particle diameter, particle shape factor, and air velocity, on the airflow field and particle deposition pattern in different zones of the lung were investigated. In addition, a genetic algorithm was employed to obtain the maximum particle deposition in the bronchial tree and the effect of the aforementioned parameters on particle deposition. Reverse flow, vortex formation, and laryngeal jet all affect the airflow structure and particle deposition pattern. The mouth-throat region had the highest deposition fraction at various flow rates. A change in the deposition pattern with an increased deposition fraction in the throat was observed owing to the increased diameter and shape factor of the particles, resulting from the higher inertia and drag force, respectively. The particle deposition analysis showed that three parameters, shape factor, diameter, and velocity, are directly related to particle deposition, and the diameter is the most effective parameter for particle deposition, with an effect of 60% compared to the shape factor and velocity. Finally, the prediction of the genetic algorithm reported a maximum particle deposition in the bronchial tree of 17%, whereas, based on the numerical results, the maximum particle deposition was reported to be 16%. Therefore, there is a 1% difference between the prediction of the genetic algorithm and the numerical results, which indicates the high accuracy of the prediction of the genetic algorithm.

Collision frequencies across collision regimes in two-component systems

Agglomeration is the most important growth process in particle systems but modelling efforts typically assume mono-disperse primary particle distributions for the closure of the collision frequency that determines the growth rates. Real systems such as sooting flames, however, involve poly-disperse primary particle distributions. Also, systems with multiple components, where primary particles are of distinct but different sizes, cannot be treated as mono-disperse. Here, we introduce bi-disperse primary particle distributions and use Langevin dynamics simulations to develop closures for the collision kernels that are applicable over a wide range of agglomerate characteristics. The simulations cover fractal dimensions from 1.4 to 2.2, primary particle diameters from 5 nm to 50 nm, primary particle size ratios from 2 to 10 and agglomerates of up to a size of 200 primary particles with varying particle compositions. The Langevin dynamics simulations cover all collision regimes from ballistic to diffusive and allow to deduce expressions for the respective collision diameters, the hydrodynamic radii and the projected area as functions of particle characteristics. It is shown that existing expressions for the transition regime that were developed for the modelling of the collision kernel of spherical particles continue to hold for collision kernels of agglomerates in two-component systems under the condition that the collision diameters and drag coefficients are modelled accurately. An example ‘a posteriori’ simulation for a particle size ratio of 6 uses the population balance equation and demonstrates that bi-variate kernels are needed for the accurate prediction of the growth rates. Errors in predicted number density at the end of the simulations are less than 12 % while mono-variate kernels developed for mono-disperse primary particle systems overpredict the growth rate by 46%.

The influence of ball milling conditions on the powder characteristics and sintering densification of Mo[sbnd]Cu alloy

Mechanical alloying was utilized to produce Mo-30Cu(wt%) composite powder. The effects of milling conditions on the powder characteristics and sintering densification were investigated. The morphological evolution during the mechanical alloying process can be categorized into four stages: 1-individual Mo and Cu particles, 2-coexistence of Mo particles and blocky MoCu composite particles, 3-coarse irregular composite particles, and 4-refined near-spherical composite particles or lamellar MoCu composite particles, depending on whether process control agent (PCA) is added. The mechanical alloying degree of the MoCu composite powder was deepened gradually from stage 1 to 4, which is influenced by the ball milling parameters. As the milling speed and milling time increase, the lattice strain and the alloying degree of the MoCu composite powders increase while the grain size of molybdenum particles decreases, which is conducive to accelerating the sintering density. Among these ball milling parameters, an elevated milling speed notably accelerates the mechanical alloying process and the sintering density. Under the milling speed of 600 r/min, ball to powder ratio (BPR) of 10:1, and milling time of 4 h, the grain size, lattice strain, and average particle diameter of the composite powder were measured to be 48.4 nm, 0.247 %, and 21.04 μm, respectively, with the particle morphology being nearly spherical. The sintered density of the MoCu composite reached 98.1 %, larger than the other composites.

Turbulence characteristics of non-spherical isolated particles with different flatness on a rough bed surface

The transport of non-spherical particles on bed is significantly influenced by flow dynamics and particle shape. To study the impact of changes in the flatness of isolated bed particles on the surrounding flow characteristics, we prefabricated three isovolumetric particles with varying levels of flatness and analyzed the flow field around them using two-dimensional particle image velocimetry measurement methods. The results show that the presence of the particles significantly alters the turbulence parameters of the surrounding flow. Specifically, the influence extends up to 1D upstream of the particles, 0.5D above the particle tops, and throughout most of the downstream region, where D represents the equivalent particle diameter. The particles cause a reduction in Reynolds stress and turbulent kinetic energy in the near-bed upstream region, with a more pronounced effect observed for particles with lower flatness. Increased particle flatness is associated with a smaller difference in the longitudinal time-averaged velocity between upstream and downstream regions. In the wake region, particle flatness shows a negative correlation with Reynolds stress, longitudinal turbulence intensity, and turbulent kinetic energy, with this effect being more pronounced closer to the particles. Quadrant analysis indicates that ejection (Q2) and sweep (Q4) quadrant events remain dominant in the presence of particles, while particle flatness positively correlates with the frequency of outward (Q1) and inward (Q3) events in the wake region and negatively correlates with the frequency of Q2 and Q4 events. This study enhances our understanding of particle-fluid interactions, particularly the response relationship between non-spherical particles and turbulent mechanisms.

Basic hydrodynamics of a pilot-scale liquid-solid inverse fluidized bed

A pilot-scale liquid-solid inverse fluidized bed (LSIFB) with 0.33 m in inner diameter and 3.0 m in height was designed and installed. Basic hydrodynamics were investigated experimentally using particles with different diameters and densities. The minimum fluidization velocity increases with the increase of particle diameter and the decrease of particle density and is independent of particle loading. Forty eight sets of data on minimum fluidization velocities from the investigation combined with the literature were collected and summarized to establish an empirical equation by modifying the Wen and Yu equation. The modified equation can predict effectively the minimum fluidization velocity across a wide range of Archimedes number. The bed expansion ratio increases with liquid velocity and particle density but decreases with the increase of particle diameter. Based on the bed expansion characteristics, an empirical equation was proposed by correlating Archimedes number and Reynolds number to predict successfully the bed expansion.

Numerical Analysis of the Influence of Preadsorbed Water on Methane Transport in Crushed Shale

Summary Methane migration in shale is affected by preadsorbed water. To understand this effect, we examined several key parameters, including the effective pore diameter Le, the pore volume distribution of Le, the effective porosity ϕe, the equivalent particle diameter da, and the water film thickness h. Using these parameters, we established an equivalent relationship linking the particle packing da and the Le and the ϕe of the capillary pores within a unit-length cuboid of particles. Based on this relationship, a conceptual model was developed to simulate methane adsorption and transport in partially saturated crushed shale, incorporating parameter estimation for the tangential momentum adjustment factor δ and methane desorption rate coefficient kd, where δ characterizes the slip flow intensity and kd is related to the Langmuir adsorption constant. The finite element method was used to calculate the methane permeability ke, Knudsen diffusion coefficient Dke, surface diffusion coefficient Ds, and adsorption phase transition rate Rm, which are all affected by adsorbed water. The model’s numerical results were validated through comparison with the results from adsorption experiments. These results revealed three distinct regions in the trend of the variation in δ with Le: a rapid increase in Region I (Le &amp;lt; 10 nm), a slowing increase in Region II (10 ≤ Le ≤ 100 nm), and a gradual increase in Region III (Le &amp;gt; 100 nm). In addition, kd is positively correlated with da. kd is also correlated with water saturation S; specifically, kd decreases when S ≤ 12%, increases when S = 12% to 45.8%, and decreases again when S exceeds 45.8%. The results also reveal overall negative correlations between h and ke, Dke, Ds and Rm. Furthermore, the rates of change in ke, Dke, Ds and Rm with increasing ε (ε is the bending coefficient associated with adsorbed water) range from 7.5% to 49.4%. Similarly, ke, Dke, and Ds increase by factors of 0.73–7.19 with increasing χ (χ is the coverage rate of the adsorbed water film). Additionally, as the adsorption time t increases, Ds initially increases rapidly, followed by a gradual increase. Between t = 500 seconds and 1,500 seconds, the rate of change in Ds decreases by 20%. Rm shows a three-stage relationship with t, namely, a rapid decrease from t = 0 seconds to 500 seconds, a steady decrease from 500 seconds to 1,000 seconds, and a stabilization from 1,000 seconds to 1,500 seconds, with Rm ranging from 1.10×10-11 mol/(m3·s) to 9.45×10-11 mol/(m3·s) overall. Ds increases with the adsorption amount ratio Ed (Ed is the ratio of the adsorption amount at t to the equilibrium adsorption amount). As Ed ranges from 0.2 to 0.6, the rate of change in Ds increases by 87% to 100%. Furthermore, Rm is negatively linearly correlated with Ed.

Preparation of (Zr0.25Hf0.25Ta0.25Nb0.25)C high-entropy ceramic nanopowders via liquid-phase precursor route at a low temperature of 1500 °C

Using citric acid, ethylene glycol, ZrOCl2·8H2O, HfOCl2·8H2O, NbCl5, and TaCl5 as raw materials, based on the principle of Pechini coordination polymerization, the (Zr0.25Hf0.25Ta0.25Nb0.25)C high-entropy ceramic precursor solution was successfully prepared, and the corresponding high-entropy ceramic powder was formed by pyrolysis at a low temperature of 1500 °C. The molecular structure of the precursor and its pyrolysis products were analyzed and characterized by different analytical and testing methods. The results show that in the precursor solution, the organic compound and the metal ions form a stable three-dimensional macromolecular structure, so that the metal ions show a uniform distribution at the molecular level, shortening the diffusion path during the carbothermal reduction reaction, thereby enabling the formation of the single-phase high-entropy carbide ceramic powders at a relatively low temperature. The obtained ceramic powders have high purity, uniform element distribution, with an average particle diameter of approximately 42 nm and an oxygen content of about 1.61 wt%. The precursor solution prepared in this study has a moderate viscosity of 20–50 mPa s and a high ceramic yield of 45 %, which is ideal for the preparation of high-entropy ceramic matrix composites.

Particle migration due to non-uniform laminar flow

Abstract Using methods of granular mechanics in the quasi-static limit, with inter-particle interactions derived from the lubrication limit, the intensity of velocity fluctuations in the slurry is associated with fluctuations in the local distribution of inter-particle distances. These are shown to consist of a vector intensity and a scalar intensity; the former couples to the first velocity gradient, the latter (which is associated with solidosity fluctuations) couples to the second velocity gradient. Rheologies for both are presented, as is the rheology that links the particle pressure to the intensity of the velocity fluctuations (also known as the ‘granular temperature’) to the dispersive pressure. The rheologies are informed by experimental results. The granular temperature profile, modified from previous work, is responsible for axial particle migration (Bagnold effect). Two broad categories are assessed: symmetrical vertical and non-symmetrical lateral flow. For the latter the roughness of the boundary walls and a non-zero density contrast are important; this case is studied for a system in which flow effects are confined to the immediate vicinity of the boundary. Sensitivity analysis reveals several key variables including the parameters that control a slipping boundary condition and the mean solidosity in the conduit. For lateral flow, a sedimentary deposit with a solidosity profile may develop near the upper or lower boundary. The theory predicts an approximate relation between the fluid-particle density contrast and sediment thickness as a function of the mean flow rate, conduit width, the mean particle diameter and fluid viscosity that has utility in a range of engineering and geological situations where particulate matter is transported in the laminar flow regime.

Curcumin-loaded lignin nanoparticles: Exploring sonication effects on drug loading and particle properties for future biomedical use

The present study investigates the effects of sonication and cross-linker (oxalic acid) concentration on drug loading and the properties of curcumin-loaded lignin nanoparticles. Selected samples were further assessed for their toxicity and antioxidant potential using the eukaryotic model organism Saccharomyces cerevisiae. Transmission electron microscopy analyses revealed the formation of spherical nanoparticles with diameters in the range of 39–49 nm. Differential scanning calorimetry experiments confirmed the encapsulation of curcumin. Factorial experimental design analyses indicated that sonication time, wave amplitude, cross-linker concentration, and their interactions significantly influenced both ζ-potential – from (−37.0 ± 1.7) mV to (−48.4 ± 0.6) mV – and curcumin loading – from (3.70 ± 0.32) % to (7.10 ± 0.57) %. These parameters are critical for biomedical applications as they relate to the clearance of nanoparticles from the human bloodstream and drug dosage optimization. Although sonication has been previously reported for the preparation of lignin nanoparticles, this study represents the first documented instance of manipulating drug loading by controlled sonication parameters. While none of the investigated factors significantly affected the mean particle diameter, observations from TEM micrographs suggest that cross-linker concentration and wave amplitude notably influence nanoparticle morphology. Moreover, the curcumin-loaded nanoparticles exhibited non-toxicity toward Saccharomyces cerevisiae and demonstrated the ability to enhance yeast cell tolerance to H2O2-induced oxidative stress, underscoring their antioxidant potential. Therefore, this research significantly contributes to the scientific understanding of how the control of sonication parameters and cross-linkers can modulate the properties of curcumin-loaded lignin nanoparticles for future biomedical applications.

Experimental research on self-amplifying density waves in horizontal pipelines of two phase granular slurries: Measurements on the effect of particle diameter and concentration

Self-amplifying density waves in hydraulic transport pipelines is a scarcely researched topic. Density waves are in essence the result of a spatial redistributing effect and clustering of solids in hydraulic transport pipelines. Self-amplifying density waves are very undesirable for practical applications, as these waves increasing the risk of pipeline blockages. The two available experimental studies (Talmon et al., 2007; Matoušek and Krupička, 2013) report conflicting properties of the density waves, such as wave length and wave celerity. This new experimental research aims to shed light on the reported differences, by broadly varying particle size and concentration in a new dedicated experiment. The main highlight of this research is that two separate mechanisms were identified that can cause density waves, and Talmon et al. (2007) and Matoušek and Krupička (2013) in hindsight were studying the two different mechanism respectively. Both wave type mechanisms come into effect at mixture velocities close to the deposit limit velocity, and require a stationary bed layer to initiate. The first mechanism is caused by an imbalance of erosion and sedimentation of the bed layer, which is predominant for fine sand particles (∼242μm and ∼308μm in this research). The second mechanism occurs when the bed layer starts sliding, instead of being eroded, and is specific for larger sand sizes (∼617μm and ∼1.08mm in this research). These two mechanisms are clearly distinguishable, having different wave lengths, celerity, amplitudes and amplification rates. The results also show a clear relationship between the mean concentration of a density wave, the wave amplitude and wave celerity specific for each of the two mechanisms.

Experimental Study on Plugging Behavior of Multitype Temporary Plugging Agents in Hydraulic Fractures

Summary Various types of temporary plugging agents are used in hydraulic fracturing to promote the uniform propagation of multicluster hydraulic fractures and increase the complexity of hydraulic fractures. However, the plugging behavior of these agents in hydraulic fractures has not yet been fully clarified, making the optimization of temporary plugging formulas challenging. In this study, dozens of plugging experiments were carried out to reveal the plugging behavior of pure fiber, pure particle, and fiber-particle combination materials in hydraulic fractures. The results indicate that the high fiber concentration and long fibers are beneficial to obtaining high maximum plugging pressures. However, the low tensile strength of fibers makes it difficult to form stable plugging layers under high pressure, especially for wide fractures. For particle plugging agents, the high rigidity of the particles prevents them from compacting tightly within the plugging layer, resulting in high permeability and low temporary plugging pressure. Excessive particle diameter and concentration tend to cause rapid blockage at the fracture entrance, leading to poor plugging performance. In contrast, the fiber-particle composite plugging scheme can form a stable and tight plugging layer at lower concentrations of both fibers and particles. Moreover, replacing single-size particles in composite with multisize particles can further enhance the plugging effect, allowing for a higher plugging pressure with a lower dosage of temporary plugging agents. Comprehensively considering the effects of material concentration and size on the plugging effect, the critical plugging quantitative characterization equations for pure fiber, pure particle, and fiber-particle combination plugging schemes are established respectively, with fracture width as the independent variable and the product of material concentration and size as the dependent variable. The temporary plugging schemes for various hydraulic fracture widths can be preliminarily determined using these equations. Based on the principle of economic optimization, the optimal temporary plugging schemes with consideration of the plugging pressure requirements were selected, which have shown good field application performance.

Multimodal 3D quantification of particle stimulated nucleation in industrially manufactured aluminium AA5182 sheet

Particle stimulated nucleation is a dominant recrystallisation mechanism observed in many industrially relevant aluminium alloys during thermomechanical processing. In this work, we quantify particle stimulated nucleation in 3D in an aluminium AA5182 alloy sheet cold-rolled to 75 % thickness reduction. Second phase particles and nuclei are mapped in the same sample volume by conventional laboratory absorption X-ray tomography and synchrotron X-ray Laue micro-diffraction. The large second phase particles are classified as Fe- and Mg-rich phases. It is found that84 % of the nuclei are particle stimulated and 40 % of the particles stimulate nucleation. The critical particle diameter is found to be 4μm. Deviatoric elastic strains are derived from micro-diffraction data and it is found that elastic strains are present in the recrystallised nuclei. The effects of the different particle types, particle clustering, particle size and aspect ratio as well as strain inheritance are discussed. This work provides a full 3D quantification of particle stimulated nucleation behaviour in AA5182 alloy sheet deformed to high strain.