Visualization of large-scale atomic interactions during the melting and crystallization process

2002 ◽  
Author(s):  
R. Durikovic
Keyword(s):  
Large Scale ◽  
Crystallization Process ◽  
Atomic Interactions ◽  
Melting And Crystallization

scholarly journals Entire crystallization process of Lennard-Jones liquids: A large-scale molecular dynamics study

2020 ◽  
Vol 152 (5) ◽  
pp. 054903 ◽  
Author(s):  
Wenze Ouyang ◽  
Bin Sun ◽  
Zhiwei Sun ◽  
Shenghua Xu
Keyword(s):  
Molecular Dynamics ◽  
Large Scale ◽  
Crystallization Process ◽  
Lennard Jones

scholarly journals Miscibility, melting and crystallization of poly(ε-caprolactone) and poly (vinyl formal) blend

2007 ◽  
Vol 25 (1) ◽  
pp. 53 ◽  
Author(s):  
David R. Rohindra ◽  
Jagjit R. Khurma
Keyword(s):  
Growth Rate ◽  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Glass Transition ◽  
Optical Microscopy ◽  
Crystallization Process ◽  
Scanning Calorimetry ◽  
Low Degree ◽  
Solution Cast ◽  
Melting And Crystallization

Solution cast blends of poly(e-caprolactone) [PCL] and poly(vinyl formal) [PVF] from dichloromethane was investigated for miscibility by Differential Scanning Calorimetry [DSC], Fourier Transform Infrared Spectroscopy [FTIR] and optical microscopy. Melting (Tm) and crystallization (Tc) temperatures were for the PCL fraction while the glass transition temperature (Tg) was for PVF fraction in the blends. Blends with 20 wt% and less PCL showed a depression in Tm and Tc. Depression in Tc indicated that during the non-isothermal crystallization process, the presence of PVF decreased the PCL segments migrating to the crystallite-melt interface thus reducing the nucleation rate, growth rate and the thickness of the lamella resulting in a depressed Tm. Crystallinity (Xc) decreased gradually with decreasing content of PCL in the blend and was due to the dilution of PCL by PVF. A depressed Tg was observed for 10 wt% PCL blend and remained the same for all other blend compositions. These observations suggested that this blend system has very low degree of miscibility. The degree of miscibility increased at low polyester concentration. FTIR spectra of the blends with low polyester concentrations showed changes in the C=O, O-H and C-O-C regions in the blended PVF and PCL spectra. Optical microscopy showed phase separation in the melt and in the PCL spherulites.

Investigating the Effect of Nanoclay Loadings and Re-Processing on the Melting and Crystallization Behavior of PP/Clay Nanocomposites

2019 ◽  
Vol 951 ◽  
pp. 21-25
Author(s):  
Achmad Chafidz ◽  
Sholeh Ma'mun ◽  
Haryanto ◽  
Wara Dyah Pita Rengga ◽  
Prima A. Handayani ◽  
...  
Keyword(s):  
Crystallization Behavior ◽  
Crystallization Process ◽  
The Other ◽  
Degree Of Crystallinity ◽  
Clay Nanocomposites ◽  
Scanning Calorimetry ◽  
Onset Crystallization Temperature ◽  
Significant Difference ◽  
The Degree Of Crystallinity ◽  
Melting And Crystallization

In this study, PP/clay nanocomposites have been fabricated at different nanoclay loadings, i.e. 0, 5, 10, and 5 wt% for the 1stcycle and 2ndcycle (re-processing). The prepared nanocomposites were then characterized by a Differential Scanning Calorimetry (DSC) to investigate the effects of nanoclay loadings and re-processing on the melting and crystallization of the nanocomposites. The DSC results showed that the melting temperature,Tmwas not significantly affected by the nanoclay loadings and re-processing. In the other hand, the degree of crystallinity,Xcof the nanocomposites was higher than that of neat PP, but only reached a maximum at nanoclay loading of 5 wt% (i.e. 51.2% for NC-5-I and 48.3% for NC-5-II). Thereafter, theXcdecreased at higher nanoclay loadings. There was no significant difference inXcbetween 1stcycle and 2ndcycle. Additionally, in all nanocomposites samples for both cycles, there were two crystallization temperatures, i.e.Tc1andTc2. In the overall crystallization process, theTcof nanocomposites increased by 11-12°C compared to that of neat PP. Whereas, the onset crystallization temperature,Tocalso increased by approx. 13°C. Apparently, there was no significant effect of nanoclay loadings and re-processing on theTcndTocof the nanocomposites.

Effect of Shear Intensity on Structure and Properties of PA1010/CaCl2 Composites

2012 ◽  
Vol 476-478 ◽  
pp. 2231-2238
Author(s):  
Sheng Jun Lu ◽  
Hua Hua Gan ◽  
Min He ◽  
Zhi Hu ◽  
Jie Yu
Keyword(s):  
Large Scale ◽  
Crystallization Process ◽  
Continuous Production ◽  
Interplanar Distance ◽  
Extreme Value ◽  
Tensile Yield Strength ◽  
Screw Speed ◽  
Melt Index ◽  
Heat Distortion Temperature ◽  
Izod Impact

The research focused on the effect of shear intensity on the crystallization process and the properties of the PA1010/CaCl2 composites which were prepared through melting extrusion. The results showed that, the interplanar distance, the crystallinity and the wavenumbers all had an extreme value when the screw speed was 240r/min. With the increasing of the shear intensity, the complexation between PA1010 and CaCl2 increased first and then decreased. The tensile strength and the heat distortion temperature of the samples increased first and then decreased, and the melt index decreased first and then increased, when the screw speed changed from 160r/min to 320r/min. All of them had an extreme value when the screw speed was 240r/min. The tensile yield strength, the flexural strength decreased with increasing of screw speed, and increased slightly or tended to a fixed value when the screw speed was more than 280r/min. The Izod impact strength rapidly decreased from 62MPa to 40.3MPa when the screw speed changed from 160r/min to 240r/min, then increased slowly with increasing of the shear intensity. The appropriate screw speed of the large-scale continuous production for the PA1010/CaCl2 composites was from 200r/min to 240r/min.

Modeling the crystal growth of cubic silicon carbide by molecular dynamics simulations

2002 ◽  
Vol 742 ◽  
Author(s):  
Nicoletta Resta ◽  
Christopher Kohler ◽  
Hans-Rainer Trebin
Keyword(s):  
Molecular Dynamics ◽  
Crystal Growth ◽  
Molecular Dynamics Simulations ◽  
Crystallization Process ◽  
Amorphous Material ◽  
Thick Layer ◽  
Atomic Interactions ◽  
Dynamics Simulations ◽  
Amorphous Sic ◽  
Cubic Silicon Carbide

ABSTRACTThe crystal growth of a seed of cubic SiC into the amorphous material has been investigated by means of classical molecular dynamics simulations. The crystallization process was studied with a set of supercells containing up to 2000 atoms, initially consisting of a 12 Å thick layer of crystalline SiC and a 18 Å thick layer of amorphous SiC at high pressure. The dynamic evolution of crystallization was then followed for several nanoseconds with the simulated annealing technique performed at constant pressure and temperature. The atomic interactions were described by the Tersoff potential. We studied the dependence of the growth process on the crystallographic orientation of the crystalline/amorphous interface by considering three different crystal planes, namely the {100}, {110}, and {111} planes. Within the pressure-temperature range considered in our simulations, we observed the crystal growth only for the {110} and the {111} orientations, but not for the {100} ones. The atomistic details of the growth mechanism are described and discussed.

Molecular dynamics simulation of the crystallization of liquid GaAs nanoparticles

2019 ◽  
Vol 33 (31) ◽  
pp. 1950392
Author(s):  
Qian Chen ◽  
Yao Zhou ◽  
Zean Tian ◽  
Tinghong Gao ◽  
Ting Xiao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Coordination Number ◽  
Large Scale ◽  
Crystallization Process ◽  
Surface Effect ◽  
Dynamics Simulation ◽  
Massively Parallel ◽  
Zinc Blende ◽  
Zinc Blende Structure ◽  
Number Form

The GaAs nanoparticles crystallization process was simulated with the molecular dynamics package large-scale atomic/molecular massively parallel simulator (LAMMPS). The results show that due to the surface effect, GaAs nanoparticles have a low melting temperature and poor order, and that their atomic thermal vibration at high temperatures is more severe than that of GaAs crystals. The crystallization process of GaAs nanoparticles begins at 970 K and generally completes at 920 K. Atoms with coordination number 3 or 4 form honeycomb-like defective (111) faces of zinc-blende structure on the surface; and atoms with a higher coordination number form two-dimensional dense structures at the subsurface.

Simple Large-Scale Synthesis of Hydroxyapatite Nanoparticles: In Situ Observation of Crystallization Process

Langmuir ◽  
2010 ◽  
Vol 26 (1) ◽  
pp. 384-388 ◽  
Author(s):  
Dong Wook Kim ◽  
In-Sun Cho ◽  
Jin Young Kim ◽  
Hae Lin Jang ◽  
Gill Sang Han ◽  
...  
Keyword(s):  
Large Scale ◽  
Crystallization Process ◽  
In Situ Observation ◽  
Hydroxyapatite Nanoparticles ◽  
Large Scale Synthesis

scholarly journals Melting and Crystallization Process of Polyethylene under High Pressure

1973 ◽  
Vol 4 (5) ◽  
pp. 526-533 ◽  
Author(s):  
Munehisa Yasuniwa ◽  
Chitoshi Nakafuku ◽  
Tetuo Takemura
Keyword(s):  
High Pressure ◽  
Crystallization Process ◽  
Melting And Crystallization

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

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