Characterization of crystal growth using a spiral nucleation model

Martins, Pedro M.; Rocha, Fernando

doi:10.1016/j.susc.2007.06.016

Cited by 16 publications

(19 citation statements)

References 43 publications

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“…20 that the overall activation energy do not vary significantly over the temperature and supersaturation ranges. From our previous study with sucrose at 40 ºC, one can estimate 14 c G kT Δ ≈ for S=0.1 [11], which is of the same order of magnitude of estimations of 24 W kT ≈ [22]. In these cases of high energetic barrier for spiral nucleation, the importance of the interfacial tension on the growth kinetics is also higher.…”

Section: Resultssupporting

confidence: 64%

“…In this concern, the interfacial tension, γ is normally thought to decrease linearly with T (Eötvös rule) [21], while the following ( ) S γ function results from the SNM, when the condition of constant growth kinetic order over the supersaturation range is observed [11]:…”

Section: Resultsmentioning

confidence: 99%

“…The new perspectives provided do not always confirm classical fundamental theories suggested more than 50 years ago. In a previous paper a new atomistic representation of crystal growth was proposed where classical concepts of two dimensional nucleation and spiral growth were combined with recent findings on the formation and development of steps from surface dislocations [11]. Through the spiral nucleation model (SNM), the crystal growth rate is related with conventional variables such as supersaturation, temperature and crystal size, and with surface properties such as the interfacial tension ( γ ), and the width and height of steps ( 0 y and h, respectively):…”

Section: Introductionmentioning

confidence: 99%

“…In a first application example of the SNM, interfacial properties were estimated from the measured influence of supersaturation on the crystal growth rates of sucrose at 40 ºC [11]. Subsequently, the same system was characterized in terms of the combined influence of supersaturation, diffusional resistance and crystal size on the crystal growth rates, by combining the SNM with the engineering approach provided by the concurrent-step model [8].…”

Section: Introductionmentioning

confidence: 99%

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Kinetic studies on the influence of temperature and growth rate history on crystal growth

Martins

Rocha

2008

Cryst. Res. Technol.

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Crystallization experiments of sucrose were performed in a batch crystallizer to study the effect of temperature and growth rate history on the crystal growth kinetics. In one of the growth methods adopted, the isothermal volumetric growth rate (R V ) is determined as a function of supersaturation (S) at 35, 40 and 45 ºC. In the other, crystals are allowed to grow at constant supersaturation by automatically controlling the solution temperature as the solute concentration decreased. Using the latter method R V is calculated as the solution is cooled. The obtained results are interpreted using empirical, engineering and fundamental perspectives of crystal growth. Firstly, the overall activation energy (E A ) is determined from the empirical growth constants obtained in the isothermal method. The concept of falsified kinetics, widely used in chemical reaction engineering, is then extended to the crystal growth of sucrose in order to estimate the true activation energy (E T ) from the diffusion-affected constant, E A . The differences found in the isothermal and constant supersaturation methods are explained from the viewpoint of the spiral nucleation mechanism, taking into account different crystal surface properties caused by the growth rate history in each method. Finally, the crystal growth curve obtained in the batch crystallizer at 40 ºC is compared with the one obtained in a fluidized bed crystallizer at the same temperature. Apparently divergent results are explained by the effects of crystal size, hydrodynamic conditions and growth rate history on the crystallization kinetics of sucrose.

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Section: Resultssupporting

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Kinetic studies on the influence of temperature and growth rate history on crystal growth

Martins

Rocha

2008

Cryst. Res. Technol.

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“…As previously stated by us for the case of crystal growth from solution (49 -51), the attachment probability linearly increases with (i) supersaturation , which drives the diffusion of molecules toward the interface; and with (ii) the number of energetically favorable sites for integration. The later quantity was found to be proportional to crystal size during crystallization (49) and is here assumed to be proportional to the length of amyloid fibrils L or, more specifically, to the number of ␤-sheets constituting the solid phase. We depart from a nonactive binding mechanism, where the lateral binding of monomers is seen as a dynamic reservoir for their subsequent incorporation at both ends of the fibrils (52,53) (Fig.…”

Section: Growthmentioning

confidence: 99%

A Generic Crystallization-like Model That Describes the Kinetics of Amyloid Fibril Formation

Crespo

Rocha

Damas

et al. 2012

Journal of Biological Chemistry

141

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Background: Amyloid fibrils are protein aggregates associated with numerous neurodegenerative diseases. Results: A theoretically consistent, two-parameter model is proposed describing very distinct amyloid fibrillization kinetics. Conclusion: Amyloid fibril formation takes place by a general mechanism involving supersaturation-dependent nucleation and growth steps. Significance: This mathematically simple model is expected to be routinely used to characterize the action of new targets for disease therapeutics.

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Microstructure and creep behavior of a new developed nickel‐base single‐crystal superalloy

Zhao

Liang

et al. 2018

Materialwissenschaft Werkst

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A new developed nickel-base superalloy is employed to prepare single-crystal castings. The as-cast and heat-treated microstructure, the creep behavior in 900 8C/ 500 MPa and 1100 8C / 140 MPa are investigated. The dendrites are well developed in the as-cast microstructure. Segregation and g' precipitation morphology difference exist between dendrite core and g/g' eutectic pool. After heat treatment the segregation is significantly decreased and the g' precipitations of all regions become much more uniform and cubic. Creep curves in varied conditions both present three stages, while the specimen in 1100 8C exhibits lower creep rate and longer life span. The fracture analysis shows that fracture style changes from mixed fracture to ductile when the temperature increases from 900 8C to 1100 8C. Porosity is the crack resource to form the facet, which is observed in both specimens. The g' precipitations raft in both specimens, while the further development of g' rafting is found in that of 1100 8C / 140 MPa, as well as the surface recrystallization with coarser rafted g/g' microstructure.

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Characterization of crystal growth using a spiral nucleation model

Cited by 16 publications

References 43 publications

Kinetic studies on the influence of temperature and growth rate history on crystal growth

Kinetic studies on the influence of temperature and growth rate history on crystal growth

A Generic Crystallization-like Model That Describes the Kinetics of Amyloid Fibril Formation

Microstructure and creep behavior of a new developed nickel‐base single‐crystal superalloy

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