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Deposited Particles (deposited + particle)

Distribution by Scientific Domains
Chemistry40%

Selected Abstracts

Growth model on (1 + 1) dimensions with local relaxation and discrete number of orientations

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2004
W. L. Cavalcanti
Abstract We introduced in this work a simple model for studying the texture formation during the electrodeposition process. Monte Carlo simulations were used to describe the formation of the deposits, and scaling concepts were also employed to characterize their growth and roughness properties. Particles are randomly deposited on a substrate, and their main axis can be aligned in a discrete set of possible directions. The final orientation of the deposited particle is determined by the interaction energy with its first neighboring particles and substrate temperature. Particle interactions are chosen according to the q -state ferromagnetic Potts model hamiltonian. Simulations were performed on (1 + 1) dimensions, for different values of temperature and substrate size. We have found different behaviors at low and high temperatures. Only at zero temperature the system reaches an absorbing state with all the layers occupied by particles oriented in the same direction. At this temperature we found the dynamic, roughness and growth exponents of the model, which satisfies the well known Family,Vicsek scaling relation for the self-affine interfaces. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Microstructure and Microhardness of Cold-Sprayed CuNiIn Coating

ADVANCED ENGINEERING MATERIALS, Issue 8 2008
W.-Y. Li
In this study, the emerging cold spraying technique was used to deposit the CuNiIn coating. The microstructure of cold sprayed Cu36Ni5In coating was examined by optical microscope, scanning electron microscope and X-ray diffraction. It was found that a very dense Cu36Ni5In coating was deposited under certain spray condition. The impact melting at the localized interfaces of the deposited particles was observed and agreed with the theoretical analysis. The coating microhardness was about 240 Hv0.2. [source]

Simulation of the dynamics of depth filtration of non-Brownian particles

AICHE JOURNAL, Issue 4 2001
V. N. Burganos
A new simulator for flow of aqueous suspensions and deposition of non-Brownian particles in granular media can predict the pattern of deposition and concomitant reduction in permeability as functions of depth, time and system parameters. The porous structure of the granular medium represented as a 3-D network of constricted pores considers the converging,diverging character of flow within pores. Using Lagrangian-type simulation the particle deposition rate was calculated. Gravity and drag, as well as hydrodynamic and physicochemical interactions between suspended particles and pore walls, were considered in calculating 3-D particle trajectories. Deposit configurations were computed, and the evolution of the pore structure was simulated at discrete time steps. Changes in the pore geometry and nature of the collector surface affect flow and trajectory computations directly. Clusters of deposited particles were allowed to become reentrained if exposed to shear stress higher than a critical value. Reentrained clusters, which moved through downstream pores, might redeposit downstream at suitable sites and cause clogging of sufficiently narrow pores. Particle clusters clogging pores have a finite permeability, which significantly affects the system's transient behavior. Clogged pores act as collectors of solitary particles and of reentrained clusters, and substantially affect the transient behavior of the filter. The loss of permeability was monitored by calculating pore and network hydraulic conductance at each time step. Numerical results for the loss of permeability, temporal evolution of filter efficiency, and specific deposit profiles are based on suspension flow simulations in a typical granular porous medium. [source]

Ferromagnetic nanoparticles embedded in self-arranged matrices

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2008
K. Rumpf
Abstract The investigated nanoscopic system, consisting of a non magnetic host material and precipitated ferromagnetic nanostructures shows a magnetic behaviour correlated to the size and shape of the deposited particles but also to their spatial distribution within the template which modifies the magnetic interactions between them. The nanostructures are deposited electrochemically into an etched silicon wafer exhibiting an array of channels of a few ten nanometers in diameter and a length up to 50 µm. The self-assembled grown templates offer the opportunity of tuning the magnetic properties by varying the geometrical characteristics of the membrane which can be loaded with different metals like Ni or Co with variable metal distribution. Magnetic characteristics like coercivity, magnetic anisotropy and temperature dependent magnetization give a survey about the structure and the magnetic interactions of the nanocomposite. This achieved ferromagnetic nanocomposite system is not only of interest for basic research but also gives rise to applications in magneto-optics, spintronics and sensor application. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Re-entrainment of wall deposits from a laboratory-scale spray dryer

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2007
M. J. Hanus
Abstract This work has determined the magnitude of re-entrainment and established the operational parameters that may be manipulated to influence re-entrainment of salt particles for a small-scale spray dryer (Buchi B-290). The wetness of the spray dryer wall deposits was found to significantly influence the magnitude of re-entrainment. It was shown both experimentally and numerically that wet deposits form at low nozzle air-to-liquid ratios (<2000), which form large droplets that dry slowly, while the initial droplet velocity did not have a large influence on wet deposition. Wet deposits form strong liquid and solid bridges, and thus deposits formed from wet particles were difficult to re-entrain. Less than 2% of deposits formed at nozzle air-to-liquid ratios less than 2000 were re-entrained, while 15.4 to 21.2% of dry deposited particles (formed at nozzle air-to-liquid ratios ranging from 2308 to 3409) were re-entrained. The threshold re-entrainment velocity of sodium chloride particles in the Buchi B-290 spray dryer was found to be between 4 and 7.7 ms,1, which is consistent with the lower-end threshold velocities presented in the literature. No significant trend relating relative humidity to the magnitude of re-entrainment was found in the 0.2,7.4% average relative humidity range, suggesting that the adhesive forces in spray dryer wall deposits are fairly constant across this relative humidity range. Decreasing wall deposit wetness through use of high (>2000) nozzle air-to-liquid ratios and use of high main gas velocities increased the re-entrainment of wall deposits in this spray dryer. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd. [source]