High-Resolution Nanoparticle Size Measurement Based on Scattering Efficiency Factor Difference Ratio Under Three-Wavelength Excitation

Comparative pulmonary toxicity study of nano-TiO 2 particles of different sizes and agglomerations in rats: Different short- and long-term post-instillation results

The dynamics of fine particles of different sizes in the vicinity of DC conductors have been studied. It was observed that the particles aggregated with each other and were distributed in parallel chains on the surface of the conductors. Moreover, an interesting “layering phenomenon” was discovered in the spaces where particles concentrated. Variations in the concentration of particles of different sizes were measured in the sump. A higher voltage and a larger particle size were found to be associated with a faster decrease in the particle concentration. Based on a coupled model of the electric field and the force field, the different forces acting on particles of different sizes were analyzed. Particles of different sizes were observed to reunite into a spindle shape in the calculation space, with large particles playing a leading role. According to the calculation results, the particles around the conductor will settle and reunite, and the gathering of particles accelerates the settlement.

Effect of the type, size and concentration of solid lubricants on the tribological properties of the polymer PEEK

Comparison of the Automated with the Semi-Automatic Coulter Counter Method and the Direct Microscopic Somatic Cell Count (DMSCC) on Raw Milk Samples

Multiple pathways for entry of calcium and other divalent cations in a vasculr smooth muscle cell line (A7r5)

Accurate estimation of production from frac-pack completed gas wells requires reliable estimation of flow properties from reservoir rocks and proppants. This study is composed of three parts: core-scale, pore-scale and reservoir-scale analyses of this problem. In the core-scale analysis, simultaneous estimation of permeability, non-Darcy, and Klinkenberg coefficients of reservoir rock is conducted from steady-state and pulse-decay experiments. Confidence intervals of the estimated parameters are determined from the Bootstrap method. The duration of pulse-decay experiments has a large impact on confidence intervals; therefore, correlations are developed to estimate the experimental duration for both 1-tank and 2-tank set-ups from the core properties and design parameters. In the pore-scale analysis, the Lattice Boltzmann method (LBM) and network modeling are used to calculate proppant flow properties. For reliable simulation, resolution- and relaxation-time effects on LBM simulation are investigated; resolution and network-structure effects for network modeling are investigated. It is found that the minimum particle diameter should be represented with 30 voxels for reliable estimations. Statistically significant permeability and non-Darcy coefficient correlations are developed by using other calculated petrophysical properties and network model parameters. A new approach, path analysis, is applied to petrophysical properties to show the relationship between them. Compaction and sand-migration effects on porosity, permeability and the non-Darcy coefficient are investigated. Trends in permeability and the non-Darcy coefficient as a function of porosity and sand concentration are found. Pore-scale simulations indicate that non-Darcy coefficients obtained from correlations always underestimate the inertial effects. A reservoir simulator is developed using the finite difference method by integrating the continuity and sand-migration equations, and by using the compaction and sand-migration correlations developed from pore-scale simulations. A parametric study is conducted for the rate constants for sand migration equations, critical velocity, flow rate, and initial movable sand concentration, to investigate their effects on sand production, reservoir flow properties, and pressure profile near the wellbore. While pore-throat plugging has a large impact on the pressure profile and reservoir flow properties, it causes an insignificant decrease in sand production. In addition, a sensitivity analysis is conducted for fracture dimensions and fracture conductivity to investigate their effects on sand production. Sand production does not decrease linearly with sensitivity parameters; therefore, designing fractures with moderate half-length, width, and conductivity is recommended.

Computational investigation of particle inertia effects on submicron aerosol deposition in the respiratory tract

The skeleton of aggregate is a determining factor for the road performance of asphalt concrete. However, the mechanical roles for different-sized particles in the compacted aggregate structure have not been clearly revealed due to the limitations of physical techniques. This paper investigates the mechanical functions of different-sized particles by developing a user-defined three-dimensional (3D) discrete element method (DEM). 3D aggregate particles with irregular shapes are modeled using clumps of spheres within Particle Flow Code in 3-Demensions (PFC3D). Digital aggregates with different gradations are constructed based on a sequential packing procedure. The air voids, mean contact number, and force proportion taken by different-sized aggregate particles are investigated for the digital aggregate mixtures. In addition, to determine the dominant particle size in the aggregate structure, a series of aggregate crushing tests are conducted in the laboratory and the particle size of crushed aggregates are analyzed. The results of this research can be applied to optimize the proportion of asphalt concrete and to develop more specific guidelines for the selection of aggregate structure.

Gas–solid fluidization has a wide range of industrial applications like catalytic reactions, combustion, gasification, etc. In a number of these applications, there is particle size reduction during the operation leading to severe entrainment and limitation of operating velocity. The various problems associated with particles of different sizes or changing particles sizes could be overcome by adopting tapered beds in fluidization operation.In the present investigation, the fluidization phenomenon in tapered beds has been critically assessed through experimental investigations using particles of different sizes and materials and wide range of apex angles of the vessels. The effect of particle size and apex angle on the fluidization behaviour is clearly brought out which has not been reported so far in literature. The importance of compressive force existing in tapered beds is highlighted.In addition, correlations for all hydrodynamic characteristics, viz. critical fluidization velocity, minimum velocity for full fluidization, maximum velocity for defluidization, peak pressure drop, fluctuation ratio, compressive force, and hysteresis have been developed some of which are proposed for the first time.

Autologous fat grafting is an effective form of soft tissue regeneration. However, the optimal fat particle size and graft retention pattern need more research. The mouse inguinal fat pad was harvested and cut into fat particles of different diameters: ≥ 5 mm, 3-4 mm, 2-3 mm, 1-2 mm and 1 mm (micro-fat). A volume of0.2 ml fat was transplanted into another mouse dorsum. Volume and retention rate were measured at 1, 4, 8 and 12 weeks. Histology analysis was performed. Immunofluorescence staining was used to evaluate M1 and M2 macrophage infiltration and graft angiogenesis. Fat retention was highest in the "> 5 mm" group and lowest in the "micro-fat" group. Large vacuoles were more common in larger-diametered fat particles. There was less collagen accumulation in the well-vascularized connective tissue in the "1-2 mm" group. The infiltrated nucleated cells peak at week 4 in groups of fat particles under 3 mm and at week 8 in in groups with fat particles above 3 mm. The number of M1 macrophages peaked at week 1 and then declined in all groups except for the "5 mm" group. The number of M2 macrophages peaked at week 4 and gradually decreased through 12 weeks in the groups below 3 mm, but increased through 12 weeks in the groups above 3 mm. Vascular intensity was similar to M2 macrophage prevalence. Fat particles of different sizes may posses different retention patterns. Larger grafts have higher retention rate but worse quality. Meanwhile, smaller grafts have better quality with lower retention rate. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The multi-scale characteristics of wall roughness are the main factors inducing particle deposition in pneumatic conveying bend pipes. However, existing simplified models cannot effectively characterize the complex features of rough walls. To elucidate the mechanism by which wall roughness regulates the deposition behavior of particles of different sizes, this study constructs a 90° bend pipe model with multi-scale random roughness characteristics based on the three-dimensional Weierstrass–Mandelbrot [three-dimensional (3D) W–M] function. By integrating the Reynolds stress model, the discrete phase model, and a critical deposition velocity model, the deposition characteristics of 1–100 μm sepiolite particles were systematically investigated. The results indicate that near-wall recirculation vortices and secondary flows are the main factors driving differences in deposition hotspots for particles of varying sizes. The particle-size screening mechanism is identified as the main reason for the enhanced deposition of particles with Stokes number (St) < 1 on rough walls. Significant differences in deposition behavior among particles of different sizes arise from the competition between adhesion-collision mechanisms. This study systematically reveals the physical mechanisms by which wall roughness regulates multi-size particle deposition, providing a theoretical basis for optimizing pneumatic conveying pipe design and reducing system energy consumption.

The diffusion of particles over an entropic potential barrier was investigated. We have considered the temperature dependence of the noise-induced escape rate of Brownian particles of different sizes between two distinct regions in a two-dimensional enclosure through a narrow bottleneck. An effective entropic potential in reduced dimension is obtained by varying the cross-section of confinement. The results of numerical integration indicate that (1) the non-Arrhenius behavior of the transition rate based on the entropy-dominated regime in the presence of an interplay of gravitational bias and thermal motion is observed and (2) in the Arrhenius region the escape rate exhibits negative correlation with the particle size under the combined action of variational size (internal cause) and relatively changed boundary (external cause).

95/05636 Method for cleaning coal in coal preparation

TiN-coated Al2O3 particles of different size, shape and crystal structure were prepared by depositing nano-size TiO2 on the Al2O3 surfaces from Ti(O-i-C3H7)4 solution (TiO2 precursor) by controlled hydrolysis, then nitrided with NH3 at 1000°C. Irrespective of the source of Al2O3 particles, a homogeneous TiO2 coating was achieved by heating from 10 to 40°C an ultrasonic suspension of the Al2O3 particles containing the precursor with 1.0 vol% H2O. After nitridation, the Al2O3 grains were coated with 10-20 nm TiN particles. Spark plasma sintering of the TiN/Al2O3 particles at 1500°C and 1600°C yielded the composite ceramics with a relative density of 94-97%. Composite TiN/Al2O3 ceramics with an electrical resistivity of ∼10-2 Ω cm were obtained at 25 vol% TiN composition.

Airborne endotoxin associated with particles of different sizes and affected by water content in handled straw