Melting Behavior of In-Flight Particles and Its Effects on Splat Morphology in Plasma Spraying

2002 ◽  
Author(s):  
H. Zhang ◽  
H. B. Xiong ◽  
L. L. Zheng ◽  
A. Vaidya ◽  
L. Li ◽  
...  
Keyword(s):  
Particle Size ◽  
Numerical Simulations ◽  
Plasma Spraying ◽  
Particle Diameter ◽  
Deposition Efficiency ◽  
Melting Behavior ◽  
Splat Morphology ◽  
Initial Particle ◽  
Unknown Parameters ◽  
Group Parameter

Effects of particle size, velocity, and temperature on the splat morphology have been well studied in the open literature. Effects of melt fraction on deposition efficiency and splat morphology are, however, not well understood. In this paper, we will focus on the melting behavior of in-flight particles and their impact on splat morphologies. A group parameter, “melting index”, has been derived to correlate the melting status of in-flight particles with particle size, velocity, and temperature which can be measured experimentally. Numerical simulations have been used to determine the unknown parameters in the melting index. The effects of initial particle diameter on the melting behavior have also been investigated.

Comparison of Micro- and Nano-Size Particle Transport and Depositions in 90 Degree Bend Microchannel

2009 ◽  
Author(s):  
Kai Zhang ◽  
Jianzhong Lin ◽  
Mingzhou Yu
Keyword(s):  
Particle Size ◽  
Electric Field ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Particle Deposition ◽  
Particle Diameter ◽  
Deposition Efficiency ◽  
Size Particle ◽  
Volume Method ◽  
Nano Size

The flow and electric field are simulated numerically with finite volume method first, then large number of nanoparticles and microparticles are injected into the microchannel separately, and these particles are traced with the Lagrangian method. It has been found that particle deposition efficiency in the bend usually decreases first then increases with particle size increasing, and there usually exists a minimum value and it corresponds to the particle diameter of about 3μm, which means that kind of particle can transport longer distance. The electric field doesn’t affect that specified value. This conclusion is helpful to the optimization of the design of microchips.

Application of Plakett-Burman Screening Design in Optimization of Process Parameters for Formulation of Canaglifozin Nanosuspension

2020 ◽  
Vol 13 (6) ◽  
pp. 5208-5216
Author(s):  
Nisha Patel ◽  
Hitesh A Patel
Keyword(s):  
Particle Size ◽  
Particle Diameter ◽  
Spherical Shape ◽  
Water Soluble ◽  
Pareto Chart ◽  
Independent Variables ◽  
Mean Particle Size ◽  
Screening Design ◽  
Stirring Time ◽  
Response Variables

In this study, we sought to improve the dissolution characteristics of a poorly water-soluble BCS class IV drug canaglifozin, by preparing nanosuspension using media milling method. A Plackett–Burman screening design was employed to screen the significant formulation and process variables. A total of 12 experiment were generated by design expert trial version 12 for screening 5 independent variables namely the amount of stabilizer in mg (X1), stirring time in hr (X2), amt of Zirconium oxide beads in gm (X3), amount of drug in mg (X4) and stirring speed in rpm (X5) while mean particle size in nm (Y1) and drug release in 10 min. were selected as the response variables. All the regression models yielded a good fit with high determination coefficient and F value. The Pareto chart depicted that all the independent variables except the amount of canaglifozin had a significant effect (p<0.001) on the response variables. The mathematical model for mean particle size generated from the regression analysis was given by mean particle size = +636.48889 -1.28267 amt of stabilizer(X1) -4.20417 stirring time (X2) -7.58333 amt of ZrO2 beads(X3) -0.105556 amt of drug(X4) -0.245167 stirring speed(X5) (R2=0.9484, F ratio=22.07, p<0.001). Prepared canaglifozin nanosuspension exemplified a significant improvement (p<0.05) in the release as compared to pure canaglifozin and marketed tablet with the optimum formulation releasing almost 80% drug within first 10min. Optimized nanosuspension showed spherical shape with surface oriented stabilizer molecules and a mean particle diameter of 120.5 nm. There was no change in crystalline nature after formulation and it was found to be chemically stable with high drug content.

scholarly journals Numerical Simulation of the Aerosol Particle Motion in Granular Filters with Solid and Porous Granules

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 268
Author(s):  
Olga V. Soloveva ◽  
Sergei A. Solovev ◽  
Ruzil R. Yafizov
Keyword(s):  
Numerical Simulation ◽  
Aerosol Particle ◽  
Particle Deposition ◽  
Particle Diameter ◽  
Deposition Efficiency ◽  
Hydrodynamic Resistance ◽  
Hydrodynamic Properties ◽  
Granular Filters ◽  
Limiting Value ◽  
Good Agreement

In this work, a study was carried out to compare the filtering and hydrodynamic properties of granular filters with solid spherical granules and spherical granules with modifications in the form of micropores. We used the discrete element method (DEM) to construct the geometry of the filters. Models of granular filters with spherical granules with diameters of 3, 4, and 5 mm, and with porosity values of 0.439, 0.466, and 0.477, respectively, were created. The results of the numerical simulation are in good agreement with the experimental data of other authors. We created models of granular filters containing micropores with different porosity values (0.158–0.366) in order to study the micropores’ effect on the aerosol motion. The study showed that micropores contribute to a decrease in hydrodynamic resistance and an increase in particle deposition efficiency. There is also a maximum limiting value of the granule microporosity for a given aerosol particle diameter when a further increase in microporosity leads to a decrease in the deposition efficiency.

scholarly journals Optimization of Yb2O3-Gd2O3-Y2O3 Co-Doped ZrO2 Agglomerated and Calcined Powders for Air Plasma Spraying

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 373
Author(s):  
Zheng Yan ◽  
Haoran Peng ◽  
Kang Yuan ◽  
Xin Zhang
Keyword(s):  
Solid Solution ◽  
Particle Size ◽  
Plasma Spraying ◽  
Cubic Phase ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Barrier Coating ◽  
Controllable Preparation ◽  
Co Doped

Yb2O3-Gd2O3-Y2O3 co-doped ZrO2 (YGYZ) is considered to be a promising material in thermal barrier coating (TBC) applications. In this study, 2Yb2O3–2Gd2O3–6Y2O3–90ZrO2 (mol.%) (10YGYZ) feedstock candidates for air plasma spraying (APS) were prepared by calcination of agglomerated powders at 1100, 1200, 1300, 1400, and 1500 °C for 3 h, respectively. Incomplete solid solution was observed in calcined powders at 1100, 1200 and 1300 °C, and the 1500 °C calcined powder exhibited poor flowability due to intense sintering effect. The 1400 °C calcined powders were eventually determined to be the optimized feedstock for proper phase structure (cubic phase), great flowability, suitable apparent density and particle size distribution, etc. 10YGYZ TBCs with the optimized feedstock were prepared by APS, exhibiting pure c phase and good chemical uniformity. Controllable preparation of coatings with different porosity (i.e., 7%–9% and 12%–14%) was realized by stand-off distance adjustment.

Adaptive Synchronization of a Stochastic Fractional-Order System

2015 ◽  
Vol 733 ◽  
pp. 939-942
Author(s):  
Xiao Jun Liu
Keyword(s):  
Numerical Simulations ◽  
Fractional Order ◽  
Stochastic System ◽  
Fractional Order System ◽  
Adaptive Synchronization ◽  
Order System ◽  
Unknown Parameters ◽  
Adaptive Laws

In this paper, adaptive synchronization of a stochastic fractional-order system with unknown parameters is studied. Firstly, the stochastic system is reduced into the equivalent deterministic one with Laguerre approximation. Then, the synchronization for the system is realized by designing appropriate controllers and adaptive laws of the unknown parameters. Numerical simulations are carried out to demonstrate the effectiveness of the controllers and laws.

scholarly journals Effect of initial particle size and various composition on the spark plasma sintering of binderless tungsten carbide

2021 ◽  
Vol 1758 (1) ◽  
pp. 012022
Author(s):  
E A Lantsev ◽  
N V Malekhonova ◽  
V N Chuvil`deev ◽  
A V Nokhrin ◽  
M S Boldin ◽  
...  
Keyword(s):  
Particle Size ◽  
Tungsten Carbide ◽  
Spark Plasma Sintering ◽  
Initial Particle ◽  
Initial Particle Size ◽  
Plasma Sintering ◽  
Spark Plasma

Effect of Diameter and Surface Area of Carbon Black Particles on Certain Properties of Rubber Compounds

1944 ◽  
Vol 17 (2) ◽  
pp. 451-474
Author(s):  
D. Parkinson
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Carbon Black ◽  
Abrasion Resistance ◽  
Particle Diameter ◽  
Stiffness Modulus ◽  
Carbon Structures ◽  
Rubber Compounds ◽  
Regular Manner ◽  
Tear Resistance

Abstract Carbon blacks can be grouped into different classes according to the way in which their fineness of division relates to different properties in rubber. Within any one class the principal properties vary in a regular manner with particle size. The normal class consists of the furnace carbons, Kosmos (Dixie)-40, Statex, the rubber-grade impingement carbons, and possibly, the color-grade impingement carbons. The subnormal classes consist of thermal carbons and acetylene and lamp blacks. Irrespective of the above classification, the properties which depend more on fineness of division than on other factors are rebound resilience, abrasion resistance, tensile strength and tear resistance. The lower limit of particle diameter for best tensile strength and tear resistance appears to be higher than that for abrasion resistance. B.S.I, hardness and electrical conductivity are properties which depend at least as much on other factors as on particle size. Stiffness (modulus) depends more on other factors than on particle size. Factors modifying the effects of particle size (or specific surface) include the presence of carbon-carbon structures and a reduction in strength of bond in rubber-carbon structures. Carbon black is thought to exist in rubber in four states: agglomerated, flocculated, dispersed, and bonded to the rubber molecules (the reënforcing fraction). Abrasion resistance is regarded as providing the only reliable measure of reënforcement.

Melting and Oxidation of Nanometer Size Aluminum Powders

2005 ◽  
Vol 896 ◽  
Author(s):  
Mikhaylo A Trunov ◽  
Swati Umbrakar ◽  
Mirko Schoenitz ◽  
Joseph T Mang ◽  
Edward L Dreizin
Keyword(s):  
Particle Size ◽  
Oxidation Behavior ◽  
Melting Behavior ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Scanning Calorimetry ◽  
Aluminum Powders ◽  
Melting Temperatures ◽  
X Ray Scattering ◽  
Powder Samples

AbstractRecently, nanometer-sized aluminum powders became available commercially and their use as potential additives to propellants, explosives, and pyrotechnics has attracted significant interest. It has been suggested that very low melting temperatures are expected for nano-sized aluminum powders and that such low melting temperatures could accelerate oxidation and trigger ignition much earlier than for regular, micron-sized aluminum powders. The objective of this work was to investigate experimentally the melting and oxidation behavior of nano-sized aluminum powders. Powder samples with three different nominal sizes of 44, 80, and 121 nm were provided by Nanotechnologies Inc. The particle size distributions were measured using small angle x-ray scattering. Melting was studied by differential scanning calorimetry where the powders were heated from room temperature to 750 °C in argon environment. Thermogravimetric analysis was used to measure the mass increase indicative of oxidation while the powders were heated in an oxygen-argon gas mixture. The measured melting curves were compared to those computed using the experimental particle size distributions and thermodynamic models describing the melting temperature and enthalpy as functions of the particle size. The melting behavior predicted by different models correlated with the experimental observations only qualitatively. Characteristic step-wise oxidation was observed for all studied nanopowders. The observed oxidation behavior was well interpreted considering the recently established kinetics of oxidation of micron-sized aluminum powders. No correlation was found between the melting and oxidation of aluminum nanopowders.

Dominant effect of particle size on the CeO2 preferential evaporation during plasma spraying of La2Ce2O7

2017 ◽  
Vol 37 (4) ◽  
pp. 1577-1585 ◽  
Author(s):  
Li-Shuang Wang ◽  
Shan-Lin Zhang ◽  
Tao Liu ◽  
Chang-Jiu Li ◽  
Cheng-Xin Li ◽  
...  
Keyword(s):  
Particle Size ◽  
Plasma Spraying ◽  
Dominant Effect ◽  
Effect Of Particle Size ◽  
Preferential Evaporation
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