Particle Diameter Research Articles

Quasi-two-dimensional dispersions of Brownian particles with competitive interactions: phase behavior and structural properties.

Competing short-range attractive (SA) and long range repulsive (LR) particle interactions can be used to describe three-dimensional charge-stabilized colloid or protein dispersions at low added salt concentrations, as well as membrane proteins with interaction contributions mediated by lipid molecules. Using Langevin dynamics (LD) simulations, we determine the generalized phase diagram, cluster shapes and size distributions of a generic quasi-two-dimensional (Q2D) dispersion of spherical SALR particles confined to in-plane motion inside a bulk fluid. The SA and LR interaction parts are modelled by a generalized Lennard-Jones potential and a screened Coulomb potential, respectively. The microstructures of the detected equilibrium and non-equilibrium Q2D phases are distinctly different from those observed in three-dimensional (3D) SALR systems, by exhibiting different levels of hexagonal ordering. We discuss a thermodynamic perturbation theory prediction for the metastable binodal line of a reference system of particles with SA interactions only, which in the explored Q2D-SALR phase diagram region separates cluster from non-clustered phases. The transition from the high-temperature (small SA) dispersed fluid (DF) phase to the lower-temperature equilibrium cluster (EC) fluid phase is characterised by a low-wavenumber peak height of the static structure factor (corresponding to a thermal correlation length of about twice the particle diameter) featuring a distinctly smaller value (≈1.4) than in 3D SALR systems. With decreasing temperature (increasing SA), the cluster morphology changes from disk-like shapes in the equilibrium cluster phase, to double-stranded anisotropic hexagonal cluster segments formed in a cluster-percolated (CP) gel-like phase. This transition can be quantified by a hexagonal order parameter distribution function. The mean cluster size and coordination number of particles in the CP phase are insensitive to changes in the attraction strength.

Influence of particle lithology, size and angularity on rates and products of bedload wear: An experimental study

AbstractPhysical wear during bedload transport influences downstream changes in the size distributions and shapes of riverbed sediment, which in turn affect myriad fluvial processes ranging from incision into bedrock to provision of aquatic habitat. Here we use laboratory tumbling experiments to address several remaining knowledge gaps, including the roles of lithologic susceptibility to fragmentation, particle size distributions and particle angularity in controlling wear rates and the size distribution of wear products. To focus on the dynamics of particle wear in headwater channels, we used initially angular sediment and ran the experiments until 10% of the initial bedload particle mass had been lost to fine‐grained wear products. We measured individual particle mass and diameter by hand and used photo analysis to quantify particle shape and angularity. We find strikingly different wear patterns between limestone and welded tuff. Although wear rates in the tuff were an order of magnitude slower than the limestone, tuff wear was primarily by fragmentation while limestone wear was dominantly by attrition. Fragmentation of the tuff resulted in a widening of the bedload size distribution, a lack of consistent particle rounding and a fine‐wear product dominated by sand. In contrast, limestone particles rounded substantially and produced silt‐sized wear products. Differences in wear product size and susceptibility to fragmentation may reflect contrasts in the size distribution of mineral crystals in each lithology. Wear rates in both rock types declined substantially with increasing cumulative mass loss, due to rounding in the limestone and reduced fragmentation in the tuff. These results suggest that applications of the conventional exponential model to predict mass loss with travel distance need to account for lithologic influence on susceptibility to fragmentation and the influence of rounding on particle wear rates.

Lyotropic liquid crystal and self-emulsifying drug delivery systems nanoparticles as artesunic acid and praziquantel carriers: An innovative approach for formulation of anti-malaria and schistosomicidal drugs

Praziquantel (PZQ) is the drug of choice for treating cestode and trematode infections, and it is currently the only option against schistosomiasis. Artesunic acid (AcART) is effective against several parasites and has emerged as an alternative for schistosomiasis treatment. However, AcART and PZQ have limited bioavailability due to poor water solubility, low permeability, and rapid cell clearance. To address these challenges, this study aimed to develop self-emulsifying drug delivery systems to develop SEDDS and NPs-LLC to overcome the low water solubility affecting AcART and PZQ bioavailability. The study involved validating the HPLC analytical methodology for AcART, SEDDS, and NPs-LLC formulations, and conducting physicochemical characterization and ex-vivo intestinal permeation assays. The composition of formulations was determined by the solubility balance of AcART and PZQ. The drug content ranged between 83 and 90 %. The anionic zeta potential was attributed to Myverol®, and the particle diameter increased slightly after the drug incorporation, while the polydispersity index indicated the relatively narrow particle size distribution. Additionally, the DSC thermogram confirmed that PZQ and AcART are in solution within SEDDS and NPs-LLC. The FTIR analysis suggests that components of SEDDS and NPs-LLC and drugs do not react to form new chemical species. The selection of specific compound formulations was based on achieving the best solubility balance. The nanostructures were stable and exhibited a surface charge favorable to mucosal permeation, with slightly superior performance for SEDDS. The innovative formulations, SEDDS and NPs-LLC, are suitable and effective carriers for AcART and PZQ.

Three-Dimensional Numerical Simulation of High-Speed Shear Crushing of High-Density Fluid

Plasma atomization is a technology that can produce high sphericity, small particle diameters, and high-purity copper powder, which is of great significance for the development of metal additive manufacturing. At present, although plasma atomization can realize the industrial preparation of spherical copper powder, there are still some problems, such as unclear understanding of the atomization process and a lack of theoretical support for powder quality control. This leads to the inability to predict the average particle diameter of powder in advance based on the actual atomization conditions and to optimize the process parameters, which seriously affects the further development of the plasma atomization process. We mainly studied the non-stationary simulation of a DC argon plasma torch. The purpose of this paper was to study the specific influence law of the average particle diameter of the powder in the process of plasma atomization by means of numerical simulation and experimental observation. The aim was to establish the mapping relationship between the atomization condition and the average particle diameter of the powder and realize the controllable preparation of the plasma atomized powder. At the same time, we used industrial-grade plasma atomization equipment to carry out pulverizing experiments to verify the plasma atomization theory and the powder average particle diameter control scheme proposed in this paper, thus proving the reliability of this study.

Effect of Coupled Microstructural Characteristics of Catalyst Layer on High Temperature: Proton Exchange Membrane Fuel Cell Performance

Abstract The widespread adoption of High Temperature-Proton Exchange Membrane Fuel Cells (HT-PEMFC) in commercial applications is limited by their performance and durability compared to conventional energy sources. A key factor affecting these cells is the sluggish oxygen reduction reaction (ORR) at the cathode catalyst layer (CL). Optimizing the structural parameters of the cathode CL can enhance cell performance and longevity. Current research on these parameters is mostly descriptive, lacking numerical evidence to quantify their impact. This study develops a three-dimensional, non-isothermal HT-PEMFC numerical model to investigate the sensitivities of coupled structural parameters of the cathode CL, including Pt loading, CL thickness, and Pt particle diameter, at three levels. The orthogonal/Taguchi approach quantitatively assesses the impact of these parameters. The study reveals that Pt loading significantly affects cell voltage and cathode overpotential, while Pt diameter influences the homogeneity of overpotential distribution. The dominant impact of a single parameter decreases at higher current densities, necessitating careful analysis of trade-offs between different structural characteristics to maximize performance. These findings offer valuable insights for future experimental studies to enhance cell performance through adjustments to cathode catalyst characteristics.

Validation of a radiosynthesis method and a novel quality control system for [68 Ga]Ga-MAA: is TLC enough to assess radiopharmaceutical quality?

BackgroundTechnetium-99 m-labelled macroaggregated human serum albumin ([99mTc]Tc-MAA) is commonly used for lung perfusion scintigraphy. The European Pharmacopoeia (Eu.Ph.) specifies thin-layer chromatography (TLC) as the only method to assess its radiochemical purity (RCP). Similarly, TLC is the sole method reported in the literature to evaluate the RCP of Gallium-68-labelled MAA [68 Ga]Ga-MAA, recently introduced for lung perfusion PET/CT imaging. Since [68 Ga]Ga-MAA is prepared from commercial kits originally designed for the preparation of [99mTc]Tc-MAA, it is essential to optimize and validate the preparation methods for [68 Ga]Ga-MAA.ResultsWe tested a novel, simplified method for the preparation of [68 Ga]Ga-MAA that does not require organic solvents, prewash or final purification steps to remove radioactive impurities. We assessed the final product using radio-TLC, radio-UV-HPLC, and radio SDS-PAGE. Overall, our quality control (QC) method successfully detected [68 Ga]Ga-MAA along with all potential impurities, including free Ga-68, [68 Ga]Ga-HSA, unlabeled HSA, which may occur during labelling process and HEPES residual, a non-toxic but non-human-approved contaminant, used as buffer solution. We then applied our QC system to [68 Ga]Ga-MAA prepared under different conditions (25°–40°–75°–95 °C), thus defining the optimal temperature for labelling. Scanning Electron Microscopy (SEM) analysis of the products obtained through our novel method confirmed that most [68 Ga]Ga-MAA particles preserved the morphological structure and size distribution of unlabeled MAA, with a particle diameter range of 25–50 μm, assuring diagnostic efficacy.ConclusionsWe optimized a novel method to prepare [68 Ga]Ga-MAA through a QC system capable of monitoring all impurities of the final products.

Experimental quantification of interparticle forces in gas-solid fluidized beds operating at temperatures from ambient to 1500 °C

The successful design and operation of high-temperature gas-solid fluidized bed reactors require a deep understanding of interparticle forces (IPFs). However, experimentally quantifying IPFs at elevated temperatures has been a significant challenge due to the lack of suitable methods. This study addresses this gap by introducing a simple yet reliable experimental approach to quantify IPFs in a gas-solid fluidized bed across a temperature range from ambient to 1500 °C. The experimental results reveal that IPFs increase gradually with temperatures up to 1200 °C and become more pronounced at higher temperatures. Smaller particles, or those prone to changes in morphological, structural, and chemical properties—such as softening, sintering, or the formation of low-melting-point eutectic compounds at high temperatures—intensify IPFs significantly. This phenomenon is corroborated by our experiments and comparison with literature data across various temperatures and particle types. Finally, two empirical correlations are proposed to predict IPFs as temperature and particle diameter functions for coarse particles in high-temperature fluidized beds. These findings enhance the understanding of IPFs in high-temperature fluidized beds and are valuable for developing such systems for industrial applications.

Acoustic black hole effect enhanced micro-manipulator

Microparticle manipulation is a critical concern across various fields including microfabrication, flexible electronics and tissue engineering. Acoustic-activated sharp structures have been designed as simple and flexible tools to manipulate microparticles with their good compatibility, fast response, and broad tunability. However, there still lacks rational acoustic-structure design for effective energy concentration at the acoustic-activated sharp structures for microparticle manipulation. Here, we present the acoustic black hole (ABH) effect as enhancement for the acoustic micro-manipulator. It provides great reliability, simplicity and ease of use, supporting custom design of high-throughput patterning modes. Moreover, compared to commonly used configurations, such as cylindrical or conical microneedles, those microneedles with ABH profile exhibit superior acoustic energy focusing at the tip and induce stronger acoustofluidic effects. The average acoustic flow velocity induced by the ABH microneedle is 154 times greater than that of the conical one and 45 times greater than that of the cylindrical microneedle. Besides, the average acoustic radiation force (ARF) produced by the ABH microneedle against acrylic microparticles is about 319 times greater than that of the cylindrical one and 16 times greater than that of the conical one. These results indicate that ABH design significantly enhances microparticle manipulation. We demonstrate this concept with ABH effect enhanced microparticle manipulation and study the parameters influencing its performance including operating frequency, operating voltage and particle diameter. Furthermore, considering the flexibility of this system, we employ it for various patterning and high-throughput microparticle manipulation. This work paves the way for controllable microparticle manipulation, holding great potential for applications in microfabrication and biomedicine.

Effect of Process Parameters on Yttria‐Stabilized Zirconia Particles In‐Flight Behavior and Melting State in Atmospheric Plasma Spraying

The preparation of coatings by atmospheric plasma spraying gives rise to complex physical processes, which present challenges to the study of plasma jet characteristics and particle in‐flight behavior. Herein, a 3D numerical model that integrates multiple physical phenomena, including electromagnetism and thermal and gas dynamics, to simulate the heating, acceleration, and melting of particles under the thermal–mechanical effect, is developed. Meanwhile, yttria‐stabilized zirconia (YSZ) coatings are prepared under varying process parameters. The DPV‐2000 system is employed for the diagnosis of particle velocity, surface temperature, and diameter. Following comparison, the simulation exhibits errors of 4.5% and 14.8% for the maximum temperature and velocity, respectively. An increase in current intensity from 500 to 600 A results in a rise in the proportion of particles exhibiting temperatures above the melting point (2963 K), from 75.1 to 93.4%, accompanied by an increase in average velocity of ≈16.6%. As the spraying distance increases from 60 to 100 mm, the proportion of particles melting decreases from 93.5 to 66.3%, and the average velocity decreases by ≈9.2%. This work will provide a theoretical foundation for the optimization of process parameters to adjust particle behavior and melting state, thus achieving an optimal spraying effect.

Application of MgO based‐nanofluid for controlling the growth of asphaltene flocs under static and micromodel dynamic conditions

AbstractIn this study, the impact of magnesium oxide (MgO) nanoparticles on the control of asphaltene aggregates growth was examined. The investigation began with static testing, followed by dynamic testing, where nanofluid was injected into a constructed glass micromodel simulating a porous medium. The results obtained from light microscopy and asphaltene dispersant tests demonstrated that the MgO nanoparticles with an average diameter of 50 nm postpone the asphaltene onset point (AOP) and delay the growth of asphaltene aggregates in crude oil. Also, the results obtained from these experiments illustrated the performance of synthesized nanoparticles in various concentrations on inhibition of asphaltene deposit in the crude oil medium, in the order of 750 > 1500 > 100 > 1000 > 500 ppm. The results from both microscopy and ADT experiments strongly validate the effectiveness of MgO nanoparticles across varying concentrations, highlighting the optimal dosage of 750 ppm. Images of nanofluid flooding at the optimal concentration in the glass micromodel demonstrate effective nanoparticle inhibition and enhanced oil recovery from the porous medium. These findings corroborate the results obtained from ADT and microscopy tests. The results of FT‐IR analysis show the adsorption of asphaltene particles on the surfaces of MgO nanoparticles in wavelengths of 2900–3000 cm−1. Moreover, dynamic light scattering (DLS) analysis results indicated that the average diameter of suspended particles was 3580 nm before adsorption and 6230 nm after adsorption, indicating the controlled adsorption of asphaltene onto the surface of MgO nanoparticles. The findings from this study can be applied to manage asphaltene formation across all stages of oil processing and production.

Efficacy of Food Industry By-Product β-Glucan/Chitin–Chitosan on Lipid Profile of Overweight and Obese Individuals: Sustainability and Nutraceuticals

Fat-binding nutraceutical supplements have gained considerable attention as potential cholesterol-lowering strategies to address dyslipidemia in overweight and obese individuals. This study aimed to evaluate the effects of a polysaccharide-rich compound containing β-glucan/chitin–chitosan (βGluCnCs) on lipid profiles and lipoprotein function. In a prospective, two-arm clinical trial, 58 overweight and obese individuals were randomized to receive either 3 g/day of βGluCnCs or a placebo (microcrystalline cellulose) for 12 weeks. Serum lipids and lipoprotein functions were assessed at baseline and at 4-week intervals throughout the study. The administration of βGluCnCs led to a significant increase in HDL cholesterol (HDLc) levels and improved HDLc/non-HDLc and HDLc/total cholesterol (TC) ratios, while reducing apolipoprotein B (ApoB) levels (p < 0.05). However, the intervention did not affect HDL particle diameter, particle number, or lipoprotein functionality. Women demonstrated greater sensitivity to changes in HDLc during βGluCnCs supplementation, whereas men exhibited a significant reduction in ApoB levels. When stratified by baseline LDL cholesterol (LDLc) levels (cut-off: 130 mg/dL), the increase in HDLc and the ApoA1/ApoB ratio was found in the low-LDL group. In contrast, the high-LDL group experienced a significant reduction in atherogenic non-LDLc and LDLc, along with an improvement in HDL’s antioxidant capacity after βGluCnCs intervention. These changes were not statistically significant in the placebo group. In conclusion, our study demonstrated that daily supplementation with βGluCnCs significantly improved lipid profiles, with effects that varied based on sex and baseline LDLc levels.

Adsorption of Congo red on magnetic cobalt-manganese ferrite nanoparticles: Adsorption kinetic, isotherm, thermodynamics, and electrochemistry.

Magnetic Co0.5Mn0.5Fe2O4 nanoparticles were successfully prepared via the combustion and calcination process, with an average particle diameter of 31.5 nm and a saturation magnetization of 25.25 emu·g-1, they were employed to adsorbe Congo red (CR) from wastewater, the Pseudo-second-order kinetic and Freundlich isotherm were consistent with the adsorption data, indicating that their adsorption was a multilayer chemisorption process, the thermodynamic investigation showed that the adsorption was a favored exothermic process. The ionic strength of Cl- in CR solution had no obvious effect on the adsorption efficiency of Co0.5Mn0.5Fe2O4 nanoparticles, and the maximum adsorbance was 58.3 mg·g-1 at pH 2, decreasing as the pH of the CR solutions increased from 2 to 12. The ion leaching experiment and XRD demonstrated that Co0.5Mn0.5Fe2O4 nanoparticles had excellent stability, and the relative removal rate was 93.85% of the first time after 7 cycles. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrated that CR was adsorbed onto Co0.5Mn0.5Fe2O4 nanoparticles, and the electrical conductivity of Co0.5Mn0.5Fe2O4 nanoparticles decreased after adsorption of CR. Magnetic Co0.5Mn0.5Fe2O4 nanoparticles displayed a promising application in wastewater treatment.

Study of the structural and phase state of ceramics synthesized from 6YSZ - Al2O3 – HfO2 by semi–dry pressing followed by sintering in vacuum

The study investigates the properties of 6YSZ – Al2O3 – HfO2 powder mixture and the resulting ceramics obtained by semi-dry pressing followed by sintering in vacuum. X-ray fluorescence spectrometry revealed the primary constituents as zirconium (81%), aluminum (8.7%), yttrium (5.7%), and hafnium (3.5%). The average particle diameter was 0.5 μm, with specific surface area and bulk weight recorded at 18,535 cm2/g and 0.84 g/cm3, respectively. X-ray phase analysis indicated a predominance of monoclinic zirconium dioxide. Sintering at 1400-1600°C transformed the phase composition, enhancing density and microhardness, with values peaking at 5.8 g/cm3 and 12.1 GPa at 1600°C. This process also increased the tetragonal phase content to 63%. The ceramics exhibited the highest crack resistance at 1600°C, attributed to the stabilized tetragonal zirconium dioxide. Microstructural analysis confirmed the homogenous distribution of the elements and the presence of fine fractions influencing microstructural properties. 1600°C was found to be the optimal temperature for sintering the 6YSZ – Al2O3 – HfO2 ceramics.

Three-Dimensional Morphological Study of MnTe-like Structures by Assessment of Tortuosity Tensor Using Computational Fluid Dynamics

This paper focuses on a morphological study of the MnTe-like structures, carried out by the evaluation of the tortuosity tensor and other related parameters using a computational fluid dynamics approach recently developed by our research group. The present work focuses on all possible crystals—existing or not developed yet—having the same structure as that of the manganese telluride. This analysis provides new information not present yet in the open literature. The motivation behind this study lies in the importance of this type of structure in physics and material science. In particular, the structures investigated are anisotropic and bi-disperse, with two independent geometrical parameters controlling the structure shape: the ratio of the particle diameters (r1) and the normalised inter-particle distance (r2). Exploiting this fact, several different structures of the same family are created, changing these two parameters independently, also allowing inter-penetration of particles to enlarge the study’s applicability. The results are primarily obtained in terms of the tortuosity tensor, needed to catch and quantify the anisotropy of the structures. Then, other morphological parameters, such as connectivity, principal diffusion directions, and anisotropy factors, are evaluated, obtaining in this way a novel morphological characterisation of the structure. It is found that high values of tortuosity are observed at lower and higher values of {r1, r2}, which means that there exists a minimum value between them. Additionally, the anisotropy factor is found to be higher at lower values of {r1, r2} and lower at higher ones. This is in accordance with the fact that, as the inter-particle distance and the ratio between particle diameters increase, the structure enlarges, which implies a lower influence of the particle distribution and, thus, a gradually more isotropic structure.

Analysis of Local Scour around Double Piers in Tandem Arrangement in an S-Shaped Channel under Ice-Jammed Flow Conditions

The stability of bridge foundations is affected by local scour, and the formation of ice jams exacerbates local scour around bridge piers. These processes, particularly the evolution of ice jams and local scour around piers, are more complex in curved sections than in straight sections. This study, based on experiments in an S-shaped channel, investigates how various factors—the flow Froude number, ice–water discharge rate, median particle diameter, pier spacing, and pier diameter—affect the maximum local scour depth around double piers in tandem and the distribution of ice jam thickness. The results indicate that under ice-jammed flow conditions, the maximum local scour depth around double piers in tandem is positively correlated with the ice–water discharge rate, pier spacing, and pier diameter and negatively correlated with median particle diameter. The maximum local scour depth is positively correlated with the flow Froude number when it ranges from 0.1 to 0.114, peaking at 0.114. Above this value, the correlation becomes negative. In curved channels, the arrangement of double piers in tandem substantially influences ice jam thickness distribution, with increases in pier diameter and spacing directly correlating with greater ice jam thickness at each cross-section. Furthermore, ice jam thickness is responsive to flow conditions, escalating with higher ice–water discharge rates and decreasing flow Froude numbers.

The Characteristics of Precipitation with and without Bright Band in Summer Tibetan Plateau and Central-Eastern China

The bright band (BB) is an important symbol of the ice–water transition zone in stratiform precipitation, and the presence or absence of BB will lead to different microphysical processes. In this paper, the characteristics of BB and precipitation characteristics with and without BB in summer at Tibetan Plateau (TP) as well as Central-eastern China (CEC) are analyzed by using Global Precipitation Measurement (GPM) and the fifth generation ECMWF atmospheric reanalysis of the global climates (ERA5) datasets. The results show the freezing level height and BB height in TP are 0.5 km higher than those in CEC. With the increase in rain rate, the BB height decreases in TP but increases in CEC. The BB width becomes wider with the increase in maximum radar reflectivity. Secondly, the maximum reflectivity factor and particle diameter of stratiform precipitation with BB appear at 5 km, while the maximum reflectivity factor of stratiform precipitation without BB and convective precipitation appear near the ground. The particle diameter first decreases and then increases from the cloud top to the ground. Thirdly, the land surface temperature of convective precipitation is about 2.5 °C higher than stratiform precipitation with BB, indicating higher land surface temperatures are more likely to trigger convection. Lastly, BB can lead to a decrease in brightness temperature and an increase in polarized difference at 89 GHZ and 166 GHZ in CEC, likely due to the increasing ice particles in stratiform precipitation with BB.

Design and fabrication of plant-based milk fat globule mimetics: Flaxseed oil droplets coated with potato, soy, or pea protein

An increasing number of plant-based milk products are appearing on the market as substitutes for dairy milk. These products are becoming more popular due to growing consumers concerns about environmental, health, or ethical issues linked to dairy milk. Typically, plant-based milks are produced using top-down approaches that involve mechanical disruption of plant tissues. In this study, we examined the possibility of using a bottom-up approach to mimic the structural and physicochemical properties of milk fat globules (MFGs) in homogenized milk. Plant-based MFGs (PB-MFGs) were prepared using flaxseed oil as an omega-3 fatty acid rich oil phase, and potato, soy, or pea protein as emulsifiers to create the interfacial membranes. PB-MFGs were prepared with the same oil content (10 %) but different protein contents (0.5, 1, 1.5, and 2 %). The mean particle diameters (d4,3 and d3,2) of the three types of PB-MFGs were slightly smaller than those of dairy MFGs, while their surface charges were somewhat more negative under neutral conditions. There was no significant difference in the shear viscosity of PB-MFGs and MFGs. In terms of stability, PB-MFGs prepared with potato protein exhibited the smallest particle size change after 30 days of storage. Moreover, the pH stability of these PB-MFGs was closest to that of dairy MFGs. Our results provide valuable insights into the design and development of plant-based milks with more dairy-like properties, which may increase their more widespread acceptance and application.

Facile preparation of multifunctional cellulose nanocrystals from coffee residue via hydrothermal technique: Prolific roles on the water purification, antibacterial and antifungal applications

In this work, the facile preparation of coffee residue (CR)-derived multifunctional cellulose nanocrystals (CNCs) via hydrothermal technique has been successfully attempted. The morphological structure, functionality, crystalline pattern, surface chemistry, elemental content and surface charge were evaluated. The adsorptive property was assessed using both anionic and cationic aqueous pollutants, chlorpyrifos and methylene blue (MB), and simulated by the non-linear isotherm models and kinetic equations. Its unique antibacterial and antifungal functions were tested against both gram-negative/positive bacterial and fungal species. The particle length and diameter, aspect ratio, crystallinity index, sulfate group content and zeta potential of this newly prepared rod-shaped CNCs were identified to be 432.39 nm, 23.57 nm, 18.34, 75.0 %, 0.21 mmol/g and −32.7 mV, respectively. CR-CNCs recorded an outstanding adsorptive feature for both MB and chlorpyrifos, with the monolayer adsorption capacities of 403.02 mg/g and 159.75 mg/g, respectively. The adsorptive uptakes could be effectively preserved via solvent regeneration technique, even after 5 adsorption-desorption runs. Excellent inhibition efficiencies against both gram-negative/gram-positive bacteria, and fungal species have been detected, with the growth-inhibition zones ranging from 10.9 to 26.7 mm. The novel protective roles of the newly prepared CR-CNCs against both biological and water contaminants have been well-elucidated.

Solar steam generation enabled by carbon black: The impact of particle size and nanostructure

AbstractHere, commercial carbon black (CB) grades are characterized in detail to determine the link between their physicochemical properties and solar steam generation performance. The CB nanoparticles used here have surface mean primary particle diameters of 11–406 nm resulting in specific surface areas of 8–300 m2/g. Thermogravimetric analysis, dynamic light scattering, Raman spectroscopy, and x‐ray diffraction reveal that fine CB nanoparticles form large agglomerates, have a more disordered nanostructure and larger organic carbon content than coarse CB grades. Most importantly, UV–vis spectroscopy and Mie theory show that increasing the particle size from 14 to 406 nm reduces the light absorption of CB dispersed in water up to 86%. So, the water evaporation flux of suspensions containing 11–14 nm CB nanoparticles is up to 25% larger than that obtained for suspensions of 406 nm particles. Thus, good control of particle size is essential to optimize the solar steam generation enabled by CB.

Computational fluid dynamics investigation of pesticide spraying by agricultural drones

Precise control over pesticide spraying by agricultural drones requires fundamental research of multiphase flow, heat and mass transfer of liquid droplets in downwash flow. In this study, water was used as a carrier agent in pesticide formulations, in which the liquid droplets exhibit a Newtonian fluid behavior. A general computational fluid dynamics (CFD) model that characterizes propeller motion coupled with droplet evaporation and deposition was developed. The downwash flow generated by the propeller rotation was simulated using a multiple reference frame method along with the SST-k-ω turbulence model. Spraying of liquid droplets was simulated using a discrete phase model. The flow model validation was conducted by comparing the simulated velocities with experimental data, and the spray model validation was completed by a comparison of droplet depositions from CFD predictions and experiments. The results indicated that the droplet deposition fluctuates with an increase of propeller speed, and that both temperature and relative humidity affect the droplet deposition. In addition, the relation between the number of particles and the impact velocity was identified quantitatively, impact velocity with respect to particle diameter was predicted, and the effects of surface inclination, surface roughness, and crosswind speed on droplet deposition were analyzed. Moreover, an in-depth discussion about the intrinsic relation between downwash flow and droplet spraying was conducted.