Nucleation parameter and size distribution of critical nuclei for nonisothermal polymer crystallization: The influence of the cooling rate and filler

2014 ◽  
Vol 132 (6) ◽  
pp. n/a-n/a ◽  
Author(s):  
Nikola Kocic ◽  
Sara Lederhofer ◽  
Karsten Kretschmer ◽  
Martin Bastian ◽  
Peter Heidemeyer
Keyword(s):  
Cooling Rate ◽  
Size Distribution ◽  
Polymer Crystallization ◽  
Critical Nuclei

The use of master curves to describe the simultaneous effect of cooling rate and pressure on polymer crystallization

2003 ◽  
Vol 53 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Vincenzo La Carrubba ◽  
Valerio Brucato ◽  
Stefano Piccarolo
Keyword(s):  
Cooling Rate ◽  
Polymer Crystallization ◽  
Master Curves ◽  
Simultaneous Effect

Crystal size distribution of benzoic acid at its crystallization from the bulk of vapour phase

1979 ◽  
Vol 44 (7) ◽  
pp. 2165-2172 ◽  
Author(s):  
Jaroslav Vítovec ◽  
Jiří Smolík ◽  
Josef Kugler
Keyword(s):  
Benzoic Acid ◽  
Cooling Rate ◽  
Size Distribution ◽  
Crystal Size ◽  
Vapour Phase ◽  
Crystal Size Distribution ◽  
Water Dispersion ◽  
Small Crystals ◽  
Permeable Walls

Crystal size and their distribution were measured in the crystallizer with gas-permeable walls, at crystallization of benzoic acid vapours from the bulk of vapour phase in the mixture with nitrogen in dependence on concentration (in range from 1.1 to 23 vol.%), temperature (401 to 473 K) and velocity of mixture (0.5 to 6.6 cm/s). At small cooling rate of the mixture the vapours of benzoic acid are condensing in the form of droplets which at continuing cooling solidify. At cooling of the mixture by water dispersion create the needle-shaped crystals. The effect of concentration, temperature and velocity is not profound obviously because by evaporation of water is the mixture rapidly cooled and supersaturated. This results in creation of a large amount of crystal nuclei and thus also of small crystals.

scholarly journals Effect of the Cooling Rate on the Graphite Nodule Count and Size Distribution in Nodular Cast Iron

2018 ◽  
Vol 925 ◽  
pp. 45-53
Author(s):  
Haji Muhammad Muhmond ◽  
Hasse Fredriksson
Keyword(s):  
Cooling Rate ◽  
Size Distribution ◽  
Great Influence ◽  
Nodular Cast Iron ◽  
Graphite Nodule ◽  
Cooling Rates ◽  
Nodule Count ◽  
Cooling Conditions ◽  
Different Temperatures ◽  
Two Parameters

The graphite nodule count, size distribution and homogenization of the nodules distribution are the factor which are of more significance for the properties of the material. By just increasing the inoculants or Mg will not help to get rid of problems like the un-even size distribution and or increasing the nodule count. The cooling conditions of the melt prior to solidification and during solidification can control these two parameters to a large extent. In this research, it is more emphasized on the nucleation sequence of MgO particles and on the cooling rates. The nucleation of MgO at different temperatures and at different cooling rates was found to have a great influence on the nodule size distribution and the homogenization of the microstructure. A mathematical model was derived to relate the Mg concentration in the liquid to the cooling rate, prior to solidification. The MgO particles count was calculated as a function of cooling rate. It was found that at higher cooling rates, MgO can be nucleated in multi steps during cooling process, which can increase the nodule count tremendously.

Modeling and Simulation of Aluminum Nanoparticle Synthesis by the Evaporation-Condensation Process Using the Nodal Method

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Heru Setyawan ◽  
Minta Yuwana
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Cooling Rate ◽  
Size Distribution ◽  
Particle Formation ◽  
Condensation Process ◽  
Particle Nucleation ◽  
Nodal Method ◽  
Vaporization Temperature ◽  
Particle Formation And Growth

In this work, a model for particle formation and growth is used to simulate the aluminum particle synthesis by an evaporation-condensation process. The effect of commonly employed process parameters (vaporization temperature, cooling rate, system pressure) is investigated. The model to be solved is the general dynamic equation (GDE) that accounts for particle nucleation, condensation and coagulation at non-isothermal conditions. The GDE was solved using the nodal method. The methodology approximates the particle size distribution to a few nodes by introducing size-splitting operators. The simulation results show that particle formation and growth take place in a short temperature range. The coagulation increases the particle size while maintaining the number concentration. On the other hand, the surface condensation tends to shift the particles size distribution towards a larger size. It was shown that production of nanoparticles with a more uniform size distribution and smaller particles are favored using low pressure and low vaporization temperature. The particle size distribution is nearly influenced by the cooling rate in the range study here.

The extinction time of a general birth and death process with catastrophes

1986 ◽  
Vol 23 (04) ◽  
pp. 851-858 ◽  
Author(s):  
P. J. Brockwell
Keyword(s):  
Laplace Transform ◽  
Size Distribution ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Death Process ◽  
Extinction Time ◽  
Birth And Death Process ◽  
Different Types ◽  
The Laplace Transform ◽  
Necessary And Sufficient

The Laplace transform of the extinction time is determined for a general birth and death process with arbitrary catastrophe rate and catastrophe size distribution. It is assumed only that the birth rates satisfyλ0= 0,λj> 0 for eachj> 0, and. Necessary and sufficient conditions for certain extinction of the population are derived. The results are applied to the linear birth and death process (λj=jλ, µj=jμ) with catastrophes of several different types.

Macrostructure and microphysics of Saturn's E-ring

1984 ◽  
Vol 75 ◽  
pp. 607-613 ◽  
Author(s):  
Kevin D. Pang ◽  
Charles C. Voge ◽  
Jack W. Rhoads
Keyword(s):  
Size Distribution ◽  
Spherical Shape ◽  
Mie Scattering ◽  
Narrow Size Distribution ◽  
Electrostatic Levitation ◽  
Volcanic Origin ◽  
Micron Diameter

Abstract.All observed optical and infrared properties of Saturn's E-ring can be explained in terms of Mie scattering by a narrow size distribution of ice spheres of 2 - 2.5 micron diameter. The spherical shape of the ring particles and their narrow size distribution imply a molten (possibly volcanic) origin on Enceladus. The E-ring consists of many layers, possibly stratified by electrostatic levitation.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

Suppression of γ’ Precipitation in a Laser-Melted Nickel-Base Alloy

1977 ◽  
Vol 35 ◽  
pp. 270-271
Author(s):  
J. M. Walsh ◽  
J. C. Whittles ◽  
B. H. Kear ◽  
E. M. Breinan
Keyword(s):  
Cooling Rate ◽  
Base Alloy ◽  
Material Surface ◽  
Intimate Contact ◽  
Absorbed Power ◽  
Perfect Contact ◽  
Nickel Base ◽  
Rapidly Solidified ◽  
Limiting Case ◽  
The Heat Transfer Coefficient

Conventionally cast γ’ precipitation hardened nickel-base superalloys possess well-defined dendritic structures and normally exhibit pronounced segregation. Splat quenched, or rapidly solidified alloys, on the other hand, show little or no evidence for phase decomposition and markedly reduced segregation. In what follows, it is shown that comparable results have been obtained in superalloys processed by the LASERGLAZE™ method.In laser glazing, a sharply focused laser beam is traversed across the material surface at a rate that induces surface localized melting, while avoiding significant surface vaporization. Under these conditions, computations of the average cooling rate can be made with confidence, since intimate contact between the melt and the self-substrate ensures that the heat transfer coefficient is reproducibly constant (h=∞ for perfect contact) in contrast to the variable h characteristic of splat quenching. Results of such computations for pure nickel are presented in Fig. 1, which shows that there is a maximum cooling rate for a given absorbed power density, corresponding to the limiting case in which melt depth approaches zero.

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