Kinetics of Magnetic Skyrmion Crystal Formation from the Conical Phase

Nano Letters ◽  
2021 ◽  
Author(s):  
Tae-Hoon Kim ◽  
Haijun Zhao ◽  
Phuong-Vu Ong ◽  
Brandt A. Jensen ◽  
Baozhi Cui ◽  
...  
Keyword(s):  
Crystal Formation ◽  
Kinetics Of

scholarly journals Defining features in the kinetics of sodium carbonate-bicarbonate solution carbonization and the quality of the resulting sodium bicarbonate crystals

2021 ◽  
Vol 4 (10(112)) ◽  
pp. 38-44
Author(s):  
Mykola Porokhnia ◽  
Musii Tseitlin ◽  
Svitlana Bukhkalo ◽  
Vladimir Panasenko ◽  
Tetiana Novozhylova
Keyword(s):  
Carbon Dioxide ◽  
Sodium Bicarbonate ◽  
Sodium Carbonate ◽  
Diffusion Resistance ◽  
Crystal Formation ◽  
Gas Velocity ◽  
Laboratory Equipment ◽  
Gas Consumption ◽  
Kinetics Of

This paper reports a study into the influence of temperature and gas consumption on the carbonization kinetics (saturation with carbon dioxide) of sodium carbonate-bicarbonate solution. The study also examined the quality and speed of crystal formation in this process. This research is predetermined by the environmental problems faced by modern enterprises that produce purified sodium bicarbonate – an insufficient degree of carbonization and, as a result, excessive air pollution with carbon dioxide, which did not participate in the reaction during the process. This study addresses these particular issues. As a result of using specialized laboratory equipment, it was found that an increase in the absorbent temperature from 79 to 85 °C leads to a decrease in the maximum degree of carbonization of the solution from 64 to 59 %. In contrast, the quality of the resulting sodium bicarbonate crystals improves but only in the range from 79 to 82 °C. With a further increase in temperature, the quality stabilizes. It is shown that the carbonization rate increases with increasing specific consumption of the absorbent (carbon dioxide) and is characterized by a negative correlation with the value of oversaturation of the absorbent in terms of NaНCO3. The quality of sodium bicarbonate crystals decreases with increasing gas velocity. Thus, it was reasonable to assume that the established dependence of the kinetics of carbonization of Na2CO3 and NaНCO3 solution on the gas velocity in the apparatus is explained by the inhibition of СО2 absorption, which is caused by the diffusion resistance of sodium bicarbonate crystallization. To improve the quality of crystals and the productivity of carbonization by reducing the supersaturation in terms of NaНCO3, it is recommended to introduce a seed crystal in the zone of binding of crystals in the carbonization columns.

Kinetics of calcium oxalate crystal formation in urine

Urolithiasis ◽  
2016 ◽  
Vol 45 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Norbert Laube ◽  
Florian Klein ◽  
Falk Bernsmann
Keyword(s):  
Calcium Oxalate ◽  
Crystal Formation ◽  
Calcium Oxalate Crystal ◽  
Kinetics Of

Kinetics of co-crystal formation with caffeine and citric acid via liquid-assisted grinding analyzed using the distinct element method

2015 ◽  
Vol 76 ◽  
pp. 217-224 ◽  
Author(s):  
Keisuke Shimono ◽  
Kazunori Kadota ◽  
Yuichi Tozuka ◽  
Atsuko Shimosaka ◽  
Yoshiyuki Shirakawa ◽  
...  
Keyword(s):  
Citric Acid ◽  
Distinct Element ◽  
Distinct Element Method ◽  
Crystal Formation ◽  
Kinetics Of ◽  
Element Method

scholarly journals Mathematical modeling of the stage of freezing in technology of lyophilized drugs

2018 ◽  
Vol 17 (2) ◽  
pp. 15-21 ◽  
Author(s):  
E. V. Blynskaya ◽  
S. V. Tishkov ◽  
K. V. Alekseyev ◽  
S. V. Minaev
Keyword(s):  
Mathematical Modeling ◽  
Crystal Size ◽  
Ice Crystals ◽  
Freezing Process ◽  
Crystal Formation ◽  
Cooling Zone ◽  
Pharmaceutical Substance ◽  
Modeling Methods ◽  
Exchange Processes ◽  
Kinetics Of

The purposeof this work is to demonstrate the existing possibilities and methodology of mathematical modeling of the freezing phase in the technology of lyophilization of vials filled with a solution containing a pharmaceutical substance and auxiliary substances. The freezing process is crucial for the subsequent stages of primary sublimation and the drying stage. So it is at the stage of freezing that ice crystals are formed and a certain microstructure forming the pores for subsequent stages and influencing the speed of all stages in the future. The developed methods allow estimating the kinetics of cooling, freezing, calculating the sizes of ice crystals and determining the permeability of the sublimation layer. Of course, for these calculations it is necessary to know the conditions and values of the variables, calculated and measured during the pilot freezing. However, modeling allows to reduce the time of development and optimization of the process, increases the speed of transfer of the technological process to other equipment. In this review, formulas are analyzed, the thermal conductivity equations for each cooling zone, equations for estimating the crystal size and pore size in the dried layer, and calculating the permeability of the sublimated layer. The article draws conclusions about the perspective of modeling methods for the freezing phase, examines the equations used in modeling and demonstrates the model of supercooling, crystal formation and other mass and heat exchange processes during the cooling and freezing stage. The calculations presented in this paper are confirmed by references to experimental data and have great practical value.

scholarly journals Microstructure and Crystallization Kinetics of Polyurethane Thermoplastics Containing Trisilanol Isobutyl POSS

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Vinicius Pistor ◽  
Daniela de Conto ◽  
Felipe Gustavo Ornaghi ◽  
Ademir José Zattera
Keyword(s):  
Crystal Size ◽  
Sem Analysis ◽  
Crystal Formation ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermoplastic Polyurethanes ◽  
Physical Interactions ◽  
Oligomeric Silsesquioxane ◽  
Kinetics Of ◽  
Batch Mixer

The synthesis of thermoplastic polyurethanes (TPU) from the reaction of a NCO group-containing prepolymer and 0, 1.14, 1.71, and 2.28 wt% of trisilanol isobutyl polyhedral oligomeric silsesquioxane (POSS) was carried out in an instrumented batch mixer. The samples were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). SEM analysis shows that the incorporation of POSS promoted strongly aggregation through physical interactions (formation of POSS-rich domains). Modifications in the TPU microstructure and the reduction in the crystal size were observed in the XRD diffractograms. The incorporation of POSS equally altered the TPU crystallization, and samples bearing higher concentrations of POSS formed two distinct types of crystalline structures. The kinetics of crystallization showed that nucleation strongly depends on the balance between TPU crystal formation and POSS-rich domains.

Role of Polymorphous Metastability in Crystal Formation Kinetics of 2,3,6,7,10,11-Hexa(4‘-Octyloxybenzoyloxy)-Triphenylene Discotic Molecules

2003 ◽  
Vol 3 (3) ◽  
pp. 375-382 ◽  
Author(s):  
Benjamin Y. Tang ◽  
Alexander J. Jing ◽  
Christopher Y. Li ◽  
Zhihao Shen ◽  
Huabin Wang ◽  
...  
Keyword(s):  
Crystal Formation ◽  
Formation Kinetics ◽  
Kinetics Of

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

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