Influence Of Particle Size Research Articles

Influence of Dose, Particle Size and Concentration on Dermal Penetration Efficacy of Curcumin.

The influence of size, particle concentration and applied dose (finite vs. infinite dose) on the dermal penetration efficacy of curcumin was investigated in this study. For this, curcumin suspensions with different particle sizes (approx. 20 µm and approx. 250 nm) were produced in different concentrations (0.625-5% (w/w)). The dermal penetration efficacy was determined semi-quantitatively on the ex vivo porcine ear model. The results demonstrated that the presence of particles increases the dermal penetration efficacy of the active compounds being dissolved in the water phase of the formulation. The reason for this is the formation of an aqueous meniscus that develops between particles and skin due to the partial evaporation of water from the vehicle after topical application. The aqueous meniscus contains dissolved active ingredients, and therefore creates a small local spot with a locally high concentration gradient that leads to improved dermal penetration. The increase in penetration efficacy depends on the number of particles in the vehicle, i.e., higher numbers of particles and longer contact times lead to higher penetration efficacy. Therefore, nanocrystals with a high particle concentration were found to be the most suitable formulation principle for efficient and deep dermal penetration of poorly water-soluble active ingredients.

Analyzing the electrochemical reduction of CO and CO2 as reactants to C1 and C2 products on copper-based flow-through gas diffusion electrodes

Electrochemical CO2 reduction (eCO2R) into useful chemicals and fuels is extensively studied, but it faces challenges such as high activation energy, carbonation, lower reaction rate, and unstable operation in alkaline conditions. In contrast, electrochemical CO reduction (eCOR) can efficiently produce C2+ products through a two-step conversion process without requiring high activation energy and involving complex reaction routes like CO2 electroreduction. Therefore, Converting CO2 to CO and then to C2+ products can be a strategic approach to enhance activity, selectivity, and economic viability. However, eCOR demonstrates lower reaction rates and sluggish kinetic with planar electrodes due to its lower solubility and poor mass transport to the electrode surface, therefore, industrially relevant current densities are still far to reach. Flow-through gas diffusion electrodes (FTGDEs) can potentially solve the issue of poor mass transport due to their abundant surface area, porous structure, and improved triple-phase interface. Herein, electrochemical CO reduction to C2+ products is investigated using Cu-based FTGDEs. A comparison of eCOR with eCO2R is also carried out to study the catalytic activity, selectivity, and stability. To demonstrate the influence of particle size, FTGDEs are designed using varying Cu particle sizes i.e. 10 nm, 100 nm, and 10 µm. The eCOR produced C2+ products with ethylene being the main product achieving 474 mA/cm2 current density and 72% faradaic efficiency at − 0.9 V vs. RHE, while eCO2R yielded more C1 products with lower catalytic activity and selectivity. Compared to gas diffusion configuration, the poor catalytic activity and selectivity of eCOR are observed in non-gas diffusion configuration which signifies that, due to higher local CO concentration and improved triple-phase generation, higher performance of FTGDEs can be obtained from gas diffusion configuration. Finally, the stable operation of Cu electrodes during eCOR highlights its promise as a highly suitable candidate for enhancing eCOR towards higher carbon products.

Investigating the influence of particle size ranges on the physical, mineralogical, and environmental properties of raw marine sediment

Annually, over one billion cubic meters of sediments are dredged worldwide. The field of construction suffer shortage of natural resources, these sediments present a potential local resource in various regions. Amongst the sectors, road construction stands as the largest consumer of aggregates, making the recovery of sediments an appealing solution. The dredged sediments made of three phases: solid, liquid, and air. The solid phase contains both mineral and organic components, each with particle size ranges. Particle size is a well-known factor significantly impacting material characteristics.This study's primary objective is to compare sediment particle size ranges as sub materials, particularly focusing on their classification for sediment recovery in road construction. The preparation of sediments for characterization tests in this context necessitates specific drying procedures, prompting an investigation into the effects of drying methods. Three distinct drying techniques-air drying, freeze drying, and oven drying were employed.Particle size ranges were extracted from raw marine sediment and categorized based on the following diameter ranges: 2–0.4 mm; 0.4–0.180 mm; 0.180–0.063 mm; and < 0.063 mm. Comprehensive physical, environmental, and chemical characterizations were conducted. The pivotal findings of this study unequivocally reveal variations in the distribution of organic matter across these different fractions. Notably, the fine fraction exerts a substantial influence on material-level attributes, especially concerning environmental characterization. Moreover, the choice of sample drying method before testing introduces variable effects on the investigated attributes. environmental impact analyses using leaching tests indicated higher values of elements like Barium (Ba), Molybdenum (Mo), Fluoride (F), and Chloride (Cl) in sediment fractions below 0.063 mm. The DRX analyses appear that the fine fraction had few clay particles, and higher values measured on different test were associated with organic matter.

Diffusion-limited C-rate as a physics-based constraint to accelerate automated design for lithium-ion batteries

Automated design for lithium-ion batteries involves optimizing electrode parameters to meet the performance goals using optimization algorithms, typically requiring thousands of iterations in one design. One possible method to accelerate the optimization is to identify the collapse point on capacity curves versus the discharge C-rate, which is related to the diffusion-limited C-rate (DLC). This work proposes applying DLC as a physics-based constraint in optimization algorithms. DLC constraints limit the initial solution space, improving the efficiency by 19.7% with the 1.5 C constraint. Additionally, we find that under certain DLC constraints, energy density and power density deviate from the generally accepted trade-off relationship. The angle difference of their negative gradient vectors is defined to calibrate the trade-off level. Further, high enough DLC constraints allow simplification of multi-object optimization with DLC constraint in an inequality form to single-object optimization with DLC constraint in an equality form, reducing the calculation time by 97% without significantly affecting the outcome. Finally, we examine the influence of electrolyte volume and particle size on optimizing results. To sum up, DLC constraints reduce the search domain and transform multi-objective problems into single-objective ones under certain conditions, thereby improving the efficiency of the automated design for lithium-ion batteries.

Influence of Ag particle size and Ag : Al2O3 surface ratio in catalysts for the chloride-promoted ethylene epoxidation

Ethylene epoxidation is catalyzed by α-alumina supported silver catalysts. The influence of silver particle size has been a topic of debate, and was typically investigated without the industrially essential chloride promoter. We studied the catalyst behavior in the presence of chloride. Transient behavior was observed in the first tens of hours on stream, not as a result of particle growth, but due to the gradual change in the nature of the active silver site in the presence of chloride. Different strategies were used to tune the particle size: either varying the silver loading or varying the decomposition atmosphere. Increasing the particle size from 13 to 50 nm by changing the Ag loading from 2 to 15 wt% increased the selectivity from 35 to 80%. However, increasing the 15 wt% Ag particle size from 48 to 184 nm by varying the heat treatment led to a decrease in selectivity from 80 to 50%. Changing the Ag particle size with both strategies also changes the Ag : Al2O3 surface ratio. The ethylene oxide selectivity is actually correlated to the Ag : Al2O3 surface ratio, rather than to the particle size in this size range. This can be explained by its influence on the probability of a formed ethylene oxide molecule to subsequently further react over support surface groups.

Investigating the Influence of Distributor Type, Particle Size and Rice Husk Percentage on Fluidized Beds through Cold Fluidization Experiments

This work studies a fluidization system through cold experiments by using a mixture of rice husk and sand to investigate three parameters: type of bed distributor (perforated plate and plate with Tuyere-type injectors), sand granulometry (mean diameters of 324 µm and 647 µm) and rice husk mass ratio (from 1% to 10% of rice husk). The results reveal that the perforated distributor plate achieved a lower minimum fluidization velocity. However, the plate with Tuyere injectors generated better mixing, thus reducing possible stagnation points. An increase in the mean diameter of the sand raises the minimum fluidization velocity but also facilitates the formation of preferential channels. As for the rice husk mass ratio, values of over 5% cause stagnation points and preferential channels. It was also found that the relation between minimum fluidization velocity and rice husk ratio follows an exponential behavior, and an equation was developed to better describe their relation.

Influence of particle size of initial oxides on the dielectric properties of ilmenite-type Zn0.7Mg0.3TiO3 ceramics

The core of this research is to elucidate the effect of the particle size of the starting oxide on the dielectric properties of Zn0.7Mg0.3TiO3 ceramics. The study was carried out using a conventional solid-state reaction route. The microstructure optimization of Zn0.7Mg0.3TiO3 ceramics was achieved by introducing nanoscale particles. The distortion of octahedral [TiO6] and the effect of crystal structure led to significant changes in the dielectric properties. Stability analysis shows that usage of nanoparticles decreases the temperature stability of Zn0.7Mg0.3TiO3 ceramics. This work will offer a well-defined guideline for the selection of raw materials to prepare ceramics in the practical production process.

Influence of talc particle size on the optical transparency, flame retardancy, and smoke release suppression of waterborne transparent fireproof coatings applied on wood surface

AbstractTalc with particle sizes of 1250 mesh (Talc‐1250), 3000 mesh (Talc‐3000), and 5000 mesh (Talc‐5000), used as synergist, was added into transparent fireproof coatings applied in wood substrates, and the influence of talc particle size on the comprehensive properties of the coatings was analyzed carefully. The results show that adding talc exerts super synergistic effect on enhancing the flame retardancy and smoke release suppression properties in the resulting coatings, and the synergistic efficiency of talc is varied with the talc particle size. Fire resistance analysis shows that the MTPPE2 coating containing Talc‐3000 exhibits better synergistic effects, accompanying a minimum back temperature of 106.3°C at 900°C and a maximum intumescent factor of 116.3. SEM‐EDS and FTIR analyses show that adding Talc‐3000 in the MTPPE2 coating contributes to the formation of a more intumescent and compact char against fire concomitant with the highest P/C mass ratio of 0.36 in char. Transparency analysis shows that the transparency of the coatings gradually decreases with the decrease of talc particle size, and the Talc‐1250 with exfoliated morphology imparts less loss of transparency to the coating while the Talc‐3000 and Talc‐5000 with intercalated morphologies induce more obvious light scattering in the coatings.Highlights Talc was used to enhance the comprehensive properties of transparent fireproof coatings. Synergistic efficiency of talc on the fire safety of coatings varies with its particle size. Talc with a particle size of 3000 mesh exerts an optimum synergism in the coatings. Transparency of the coatings gradually decreases as talc particle size decreases.

Kinetic modeling of phenolic compounds extraction from nutshells: influence of particle size, temperature and solvent ratio

This paper studies the effects of particle size, temperature and ethanol–water solvent ratio on the extraction of total phenolic compounds (TPC) from peanut, coconut, and macadamia nutshells. Using an I-optimal design, the maximum TPC extraction obtained from the shells ranged from 63.5 ± 1.6 to 76.2 ± 3.1 mg gallic acid equivalent (GAE) per 100 g dry weight (dw) of nutshell. Next, a response surface model (RSM) was developed to describe the relationship between the process parameters and the extracted TPC concentration, in order to predict the optimal extraction conditions. For all of the examined biomasses, the optimal conditions for extraction were predicted at a particle size of 1 mm, temperature of 75 °C and ethanol/water mixture of 54, 53 and 65% ethanol, for peanut, coconut and macadamia nutshells respectively. Particle size seems to be the most important parameter, while temperature appears to be of lesser importance. Besides, the extraction kinetics were assessed by fitting kinetic models on the experimental data. The combined second-order diffusional model provided the best goodness of fit. This model revealed that, at the boundary layer, the effect of washing mechanism of extraction is more important than extraction due to diffusion kinetics. This study provides an understanding of the mass transfer mechanism involved in the TPC extraction process from nutshells, which yields valuable insights that could facilitate the industrial biorefinery of nutshells.Graphical

Drying behaviour of nanofluid sessile droplets on self-affine vis-à-vis corrugated nanorough surfaces.

In recent years, evaporative self-assembly of sessile droplets has gained considerable attention owing to its wide applicability in many areas. While the phenomenon is well studied for smooth and isotropically rough (self-affine) surfaces, investigations comparing the outcomes on self-affine vis-à-vis corrugated surfaces remains to be done. In this experimental work, we compare the wetting and evaporation dynamics of nano-colloidal microlitre droplets on self-affine and corrugated nanorough surfaces having identical roughnesses and interface properties. The coupled influence of particle size, concentration, and surface structuring has been explored. Differences in wettability and evaporation dynamics are observed, which are explained via the interaction between wetting fluid and anisotropic surface roughness. Our findings exhibit different temporal behaviour of contact radius and angle in the evaporation process of the droplets. Further, the corrugated surface exhibits anisotropic wettability with a monotonic change in droplet shape as evaporation proceeds, finally giving rise to irregular dried patterns. The scaled rim width and crack spacing of the particulate deposits are examined. Our results can inspire fabrication of surfaces that can facilitate direction-dependent droplet motion for specific applications.

Levulinic to succinic acid transformation over Ru based catalysts

In this work ruthenium based catalysts are tested as catalytic systems for the selective oxidation of levulinic to succinic acid. Very different in nature supports have been chosen in order to elucidate the effect of their textural and acidic properties on the final catalytic activity. The influence of Ru particle size is also discussed and proposed as one of the key factors. Medium range ruthenium particles supported on relatively acid supports are the best performing systems in terms of succinic acid yield, while the most active catalysts in terms of conversion result in important carbon loss due to reagent/products full oxidation.

The Effect of Different Particle Sizes of SiO2 in Sintering on the Formation of Ternesite

Ternesite is synthesized through sintering a mixture of CaCO3, SiO2, and CaSO4 in a molar ratio of 4:2:1. Ternesite has a hydration rate between ye’elimite and belite in an aluminum-containing environment, and is considered to be a new material that can be used to enhance the performance of calcium sulphoaluminate cements. This experiment investigated the influence of different particle sizes of SiO2 on ternesite formation. Controlled partial pressure sintering was employed within the temperature range from 1100 °C to 1200 °C, with a 72 h incubation period. The highest purity of ternesite in the samples reached 99.47% (500 nm SiO2 sample). The analysis results from scanning electron microscopy and an energy dispersive spectrometer indicated that the particle size of SiO2 exerted a significant influence on the formation of ternesite. In the preparation of ternesite from 10 μm particle size SiO2, traces of calcium silicate were found in the product. The results of a thermal analysis further demonstrated significant distinctions in the thermal stability of ternesite prepared with SiO2 of different particle sizes. Additionally, the crystallinity of ternesite was influenced by the particle size of SiO2, consequently impacting the hydration performance of ternesite–calcium sulphoaluminate cement.

Metal-based electrocatalysts with data-driven designed particle size for hydrogen evolution

Metal-based catalysts are currently at the forefront of hydrogen evolution catalysts, yet the influence of particle size on their catalytic activity is intricate. In this study, we compiled a database using actual test results and employed interpretable algorithms to analyze the relationship of catalyst factors with their catalytic properties. Our analysis revealed a bowl-shaped correlation between the measured overpotential and the particle size of metal-based catalysts, with the optimal size falling within the range of 1.5 to 3.0 nm. To corroborate the algorithmic analysis, we synthesized nanoalloys using an ultrathin carbon layer, which effectively restricted the movement of metal atoms at high temperatures. The series of materials prepared displayed a consistent pattern in their measured overpotential, aligning with our algorithm’s prediction. Notably, the 2.0 nm PtCoNi catalyst achieved superior catalytic performance with lower precious metal content than commercial Pt/C. Further data-driven analysis indicates that the size-dependent catalytic activity is shaped by the balance between metal-support interaction and the exposure ratio of the active site. This study underscores the efficacy of merging a data-driven approach with precise control of material synthesis to analyze complex catalytic systems, providing a potent tool for future exploration in the field.

Influences of changes in pH, temperature, and particle size on surface reaction resistance and diffusion resistance in the struvite dissolution process

Struvite (MgNH4PO4·6 H2O，MAP), a type of high-quality, slow-release fertilizer, is the main component of urinary stones in animals and humans and causes scale formation in industrial pipes. Therefore, MAP dissolution is an important research topic. Herein, MAP dissolution experiments are performed and a thermodynamic model is developed to evaluate the influences of pH, temperature (T), and particle size (Ps) on surface reaction resistance (1/ks) and diffusion resistance (1/kd). The results show that MAP solubility decreases with an increase in pH and the effects of pH change are more obvious than those of T or Ps. The total resistance (1/kT) of MAP dissolution increases with pH increase, Ps growth, or T reduction. The comparison of 1/ks and1/kd reveals surface reaction as the MAP dissolution control step and indicates a linear relation among 1/ks, 1/kd, and the natural logarithm of Ps at pH 7.0.

The creep characteristics and related evolution of particle morphology for calcareous sand

In the study, the creep characteristics and meso-mechanism of calcareous sand under different stresses are explored through triaxial creep tests. The influence of particle size on calcareous sand creep is also considered. Furthermore, the particularity of calcareous sand creep is revealed by comparing with the creep behavior of silica sand. The results show that during creep, the calcareous sand is more stable than silica sand due to the interlocking of irregular particles. When creep deviatoric stress is small, the creep of calcareous sand is manifested as nonlinear attenuation creep (primary creep), and the creep deformation is smooth without creep failure. With the increase of creep deviatoric stress, the creep deformation is concentrated, resulting in a strain concentration zone similar to the shear band, and the associated creep rate first decreases and then suddenly increases, finally, creep failure occurs. With increasing particle size of calcareous sand, the particle crushing increases, which induces a higher creep deformation, however, the overall creep failure is not generated. During the graded creep of calcareous sand, an obvious creep structural effect is observed, which is temporary and results in a significantly reduction of creep rate. Only after the previous creep structure effect is destroyed by the continuously creep process, the creep response can restore to its original behavior. The meso-behavior is represented by particle morphology, i.e., the fractal dimension and aspect ratio. It is found that both confining pressure and particle size can influence the evolution of particle morphology during creep. With the increase of confining pressure, the fractal dimension of calcareous sand decreases which means that particle grinding is always existent, while the aspect ratio of small-sized calcareous sand after creep decreases first and then stabilizes (slightly increases), suggesting that the overall particle breakage is the main cause of deformation. However, the aspect ratio of large-sized calcareous sand continually decreases, indicating that the main contribution for its deformation is angular cracking. The mesoscopic behavior of silica sand is basically unaffected by creep, and its creep deformation is mainly caused by particle rearrangement.

The effect of the design of the mini cyclonic DPIs on the emitted dose by modelling approach

Although dry powder inhalers (DPIs) provide distinct advantages for delivering aerosols to patients, there are still barriers that need to be passed through such as low in vivo efficiency, drug agglomeration, and inconsistency of delivered dose at different flow rates. Cyclones have widely been used in many fields, including powder inhalation drug delivery. With a good design based on mechanistic understanding, small portable cyclones may have the potential to overcome some of the above-mentioned shortcomings. However, the investigation of the miniature cyclone to optimize DPIs for inhalation drug delivery is still limited. Ten miniature cyclones are designed for studying the effects of different geometric parameters, various flow rates, and particle sizes on device-emptying by modelling approach. The simulation results indicated that different cyclones have different distributions of fluid fields. The emitted fraction (EF) is highly sensitive to cyclone geometries and particle size. For most models, the impact of the flow rate on EF is not obvious, and it can be ignored if the inhalation rate exceeds 45L/min. The particle size distribution can be controlled by adjusting the cyclone parameters. This paper provides a comprehensive insight into the influence of geometric parameters, particle sizes, and flow rates on the EF of miniature cyclones. The results should be helpful for designing new devices based on the different delivery requirements, which is beneficial for the future improvement of inhaler devices.

Tightly focused linearly and radially polarized beam effect on the LSPR peak with varying particle size

Interactions of gold and silver spherical nanoparticles (NPs) of a wide range of radius size with tightly focused beams are investigated for a wide range of wavelengths. The scattering of tightly focused beams with a single NP of varying size is examined using a generalized Mie theory and average intensity enhancement in the near-field due to localized surface plasmons is examined for different tightly focused beams. A multipole expansion approach is used to observe the contribution of modes in shaping the scattered light intensity. Influence of particle size and tightly focused beam on intensity enhancement factor is investigated and a shift in localized surface plasmon resonance (LSPR) peak towards higher wavelength is observed with increasing particle size. Maximum intensity enhancement factor due to scattering of different incident beams by a metallic NP is theoretically examined and reported. Gold and silver NP having radius size ranging from 30–60 nm and 1–15 nm respectively showed a maximum intensity enhancement factor in different media. A significant enhancement for the tightly focused radially polarized beam is observed for gold and silver NPs of radius size between 50 nm and 100 nm. Variation towards higher wavelength in LSPR peak due to involvement of higher order of multipoles, and the surrounding medium are also examined in detail.

Fabrication of diamond/copper composite thin plate based on a single-layer close packed diamond particles network for heat dissipation

High-efficiency heat dissipation is crucial for the reliability and durability of high-power electronics devices. Diamond/copper composites have drawn much attention as promising candidate materials for thermal management due to their high thermal conductivity and tunable coefficient of thermal expansion. In this work, a novel method was proposed to fabricate a thin plate of diamond/copper composite based on the construction of single-layer close packed diamond particles network. The composite with a sandwich structure was prepared by press-brazing method, which is cost-effective for both preparation and post-processing. The microstructures of the composite plate containing diamond, AgCuTi filler and Cu were examined. The influence of diamond particle size on thermal conductivity, coefficient of thermal expansion, and mechanical properties were also experimentally measured and theoretically simulated. The results show that a single-layer close packed diamond particles network is densely brazed between copper layers to form a composite thin plate. The interface TiC layer is in-situ formed between diamond and AgCuTi matrix. With increase in the diamond particle size to 1200 μm, thermal conductivity of 552.7 W⋅m−1⋅K−1, coefficient of thermal expansion of 10.1 × 10-6 K−1, and flexural strength of 204.3 MPa are achieved, which are in agreement with the theoretical simulated results. As a heat spreader substrate, the heat dissipation ability of diamond/Cu composite is increased by 5.7 °C in comparison with pure Cu plate. Finite element analysis and testing of actual scenarios further confirm the excellent thermal performance of the sandwich structured diamond/Cu composite thin plate, making it a prospective candidate for thermal management.

3D computational fluid and particle dynamics simulations: metrics of aerosol capture by impaction filters * *Contribution of NIST; not subject to U.S. copyright. Certain commercial equipment, instruments, software, or materials are identified in this paper in order to specify the experimental procedure and virtual experimentation adequately. Such identification is not intended to imply recommendation or endorsement by NIST, nor is

Human studies provide valuable information on components or analytes recovered from exhaled breath, but there are limitations due to inter-individual and intra-individual variation. Future development and implementation of breath tests based on aerosol analysis require a clear understanding of how human factors interact with device geometry to influence particle transport and deposition. The computational fluid and particle dynamics (CFPD) algorithm combines (i) the Eulerian approach to fluid dynamics and (ii) the Lagrangian approach to single particle transport and deposition to predict how particles are carried in fluids and deposited on surfaces. In this work, we developed a 3D multiscale CFPD model to provide insight into human factors that could be important to control or measure during sampling. We designed the model to characterize the local transport, spatial distribution, and deposition of polydisperse particles in a single impaction filter of a commercial aerosol collection device. We highlight the use of decoupling numerical strategies to simultaneously quantify the influence of filter geometry, fluid flowrate, and particle size. Our numerical models showed the remarkable effect of flowrate on aerosol dynamics. Specifically, aerosol mass deposition, spatial distribution, and deposition mechanisms inside the filter. This work as well as future studies on the effect of filter geometry and human factors on aerosol collection will guide the development, standardization, and validation of breath sampling protocols for current and emerging breath tests for forensic and clinical applications.

Study on the Sliding Tribological Behavior of Oleic Acid-Modified MoS2 under Boundary Lubrication.

The effects of MoS2 and MoS2 modified by adding oleic acid (OA) on the friction properties of lithium-based grease under boundary lubrication conditions are studied by molecular dynamics (MD) simulation and experiment. A rough wall boundary lubrication MD model with peaks and grooves is established to simulate the mechanical properties and lubrication effects of three lubrication systems on rough walls for the relative shear velocity between the two solid walls of 5 m/s at 500 MPa. The stress, wear amount, friction force, normal pressure, and friction heat of the friction surface are quantitively calculated. Simultaneously, a Retc friction and wear testing machine is used to measure the friction coefficient under different concentrations of additives and different pressures. The results show that the grease added with MoS2 can reduce friction, wear, and the temperature between friction pairs. However, under high pressure and shear, MoS2 can easily agglomerate and accumulate in the pits, reducing the lubricating effect. At the same time, since OA-modified MoS2 can reduce agglomeration, the modified MoS2 is adsorbed on the metal wall surface, forming a stable lubricant film. The main contributions of this article can be found in combining MD simulation and experimentation, establishing the connection between micronano structures and macroscopic properties, exploring the mechanism of the influence of wall roughness and particle size on the friction performance of lubricating oil, and providing a theory for predicting and developing high-performance new lubricating grease.