Vortex flows in acid solutions of lithium dihydrogen phosphate in a crystal growth unit

We discuss the results of a computer simulation of the biopolymer crystal growth and aggregation based on the 2D lattice Monte Carlo technique and the HP approximation of the biopolymers. As a modeled molecule (growth unit) we comparatively consider the previously studied non-mutant lysozyme protein, Protein Data Bank (PDB) ID: 193L, which forms, under a certain set of thermodynamic-kinetic conditions, the tetragonal crystals, and an amyloidogenic variant of the lysozyme, PDB ID: 1LYY, which is known as fibril-yielding and prone-to-aggregation agent. In our model, the site-dependent attachment, detachment and migration processes are involved. The probability of growth unit motion, attachment and detachment to/from the crystal surface are assumed to be proportional to the orientational factor representing the anisotropy of the molecule. Working within a two-dimensional representation of the truly three-dimensional process, we also argue that the crystal grows in a spiral way, whereby one or more screw dislocations on the crystal surface give rise to a terrace. We interpret the obtained results in terms of known models of crystal growth and aggregation such as B-C-F (Burton-Cabrera-Frank) dislocation driven growth and M-S (Mullins-Sekerka) instability concept, with stochastic aspects supplementing the latter. We discuss the conditions under which crystals vs non-crystalline protein aggregates appear, and how the process depends upon difference in chemical structure of the protein molecule seen as the main building block of the elementary crystal cell.

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Studies on nucleation and crystal growth kinetics of plutonium(IV) oxalatex

Radiochimica Acta ◽

10.1515/ract-2021-1074 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Chuanbo Li ◽

Bo Wang ◽

Xiang Li ◽

Taihong Yan ◽

Weifang Zheng

Keyword(s):

Growth Rate ◽

Crystal Growth ◽

Nucleation Rate ◽

Crystal Growth Rate ◽

Acid Solutions ◽

Dilution Ratio ◽

Secondary Nucleation ◽

Supersaturation Ratio ◽

Crystal Growth Kinetics ◽

Kinetics Of

Abstract A new method is developed to calculate the dilution ratio N of the two reactant solutions during nucleation rate determination. When the initial apparent supersaturation ratio S N = f(N) in the dilution tank is controlled between 1.66 and 1.67, the counted nuclei is the most, both nuclei dissolving and secondary nucleation avoided satisfactorily. Based on this methoed, Plutonium(IV) oxalate is precipitated by mixing equal volumes of tetravalent plutonium nitrate and oxalic acid solutions. Experiments are carried out by varying the supersaturation ratio from 8.37 to 22.47 and temperature from 25 to 50 °C. The experimental results show that the nucleation rate of plutonium(IV) oxalate in the supersaturation range cited above can be expressed by the equation R N = A N exp(−E a /RT)exp[−B/(ln S)2], where A N = 4.8 × 1023 m−3 s−1 , and E a = 36.2 kJ mol−1, and B = 20.2. The crystal growth rate of plutonium(IV) oxalate is determined by adding seed crystals into a batch crystallizer. The crystal growth rate can be expressed by equation G(t) = k g exp(−E’ a /RT) (c − c eq) g , where k g = 7.3 × 10−7 (mol/L)−1.1(m/s), E’ a = 25.7 kJ mol−1, and g = 1.1.

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Thermodynamics of Potassium Dihydrogen Phosphate Growth: Baseline for Understanding Single-Crystal Formation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.581-582.727 ◽

2012 ◽

Vol 581-582 ◽

pp. 727-730 ◽

Cited By ~ 5

Author(s):

Xu Zhang ◽

De Xiang Jia ◽

Hua Xie

Keyword(s):

Crystal Growth ◽

Surface Energy ◽

Surface Chemistry ◽

Thermodynamic Description ◽

Potassium Dihydrogen Phosphate ◽

Dihydrogen Phosphate ◽

Crystal Formation ◽

Kdp Crystal ◽

Potassium Dihydrogen ◽

Effect Of Surface

The geometric shape of a crystal can be simulated via a thermodynamic model using breaking bond energy calculations. When this model was applied to the case of the KDP crystal, a thermodynamic description of the KDP crystal growth was successfully developed, which was consistent with experimental observations. Additionally, the effect of surface chemistry on the morphology of the KDP crystal was also investigated using the model based on the surface energy of the KDP crystal. These results confirm that bond making and breaking strongly influence the thermodynamic morphology of the KDP crystal during the crystallization.

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