Primary nucleation of polyethylene: Embryogenesis from a semidilute solution

Polymer ◽  
2014 ◽  
Vol 55 (14) ◽  
pp. 3087-3092 ◽  
Author(s):  
Yi-Kang Lan ◽  
An-Chung Su
Keyword(s):  
Primary Nucleation ◽  
Semidilute Solution

Sodium salt scaling in black liquor evaporators and the effects of the addition of tall oil brine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Erik Karlsson ◽  
Anders Åkesjö
Keyword(s):  
Sodium Carbonate ◽  
Sodium Salt ◽  
Black Liquor ◽  
Sodium Sulphate ◽  
Salt Solutions ◽  
Tall Oil ◽  
Sulphate Content ◽  
Inhibition Effect ◽  
Salt Scaling ◽  
Primary Nucleation

AbstractSodium salt scaling, i. e. the formation of doubles salts comprised of sodium, carbonate and sulphate on the heat transfer surfaces, is a common problem that occurs during black liquor evaporation. In this study, experimental results are presented that provide new insights into the formation and composition of such scales and how they are influenced by the addition of tall oil brine. It was found that increased content of sodium carbonate and sodium sulphate in the black liquor increased scaling, while the ratio between carbonate and sulphate had a lesser influence than reported in other studies. Black liquor created loose clay-like scales comprised of aggregated crystals and black liquor, whereas salt solutions created hard mineral-like scales. The scales formed by both the black liquor and the salt solution showed a tendency to fall off during formation after primary nucleation. It was also found that both tall oil soap and alkalized tall oil brine could inhibit the formation of scales. The inhibition effect is stronger if adding the soap or brine just before scaling starts, but also depends on the amount added, the sodium carbonate and sodium sulphate content in the liquor as well as other factors.

scholarly journals Understanding the Salt-Dependent Outcome of Glycine Polymorphic Nucleation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 262
Author(s):  
Guangjun Han ◽  
Pui Shan Chow ◽  
Reginald B. H. Tan
Keyword(s):  
Rare Case ◽  
Depth Data ◽  
Data Analyses ◽  
Primary Nucleation ◽  
Bulk Solutions

The salt-dependent polymorphs of glycine crystals formed from bulk solutions have been a longstanding riddle. In this study, in order to shed fresh light, we studied the effects of seven common salts on primary nucleation of the metastable α-glycine and the stable γ-glycine. Our nucleation experiments and in-depth data analyses enabled us to reveal that (NH4)2SO4, NaCl and KNO3, in general, promote γ-glycine primary nucleation very significantly while simultaneously inhibiting α-glycine primary nucleation, thereby explaining why these three salts induce γ-glycine readily. In comparison, Ca(NO3)2 and MgSO4 also promote γ-glycine and inhibit α-glycine primary nucleation but not sufficiently to induce γ-glycine. More interestingly, Na2SO4 and K2SO4 promote not only γ-glycine but also α-glycine primary nucleation, which is unexpected and presents a rare case where a single additive promotes the nucleation of both polymorphs. As a result, the promoting effects of Na2SO4 and K2SO4 on γ-glycine do not enable γ-glycine nucleation to be more competitive than α-glycine nucleation, with γ-glycine failing to appear. These observations help us to better understand salt-governed glycine polymorphic selectivity.

scholarly journals Curcumin Inhibits the Primary Nucleation of Amyloid-Beta Peptide: A Molecular Dynamics Study

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1323
Author(s):  
Irini Doytchinova ◽  
Mariyana Atanasova ◽  
Evdokiya Salamanova ◽  
Stefan Ivanov ◽  
Ivan Dimitrov
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bonds ◽  
Amyloid Beta ◽  
Amyloid Plaques ◽  
Amyloid Beta Peptide ◽  
Aβ Peptides ◽  
Amyloid Peptides ◽  
Primary Nucleation ◽  
Beta Peptide ◽  
Good Agreement

The amyloid plaques are a key hallmark of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Amyloidogenesis is a complex long-lasting multiphase process starting with the formation of nuclei of amyloid peptides: a process assigned as a primary nucleation. Curcumin (CU) is a well-known inhibitor of the aggregation of amyloid-beta (Aβ) peptides. Even more, CU is able to disintegrate preformed Aβ firbils and amyloid plaques. Here, we simulate by molecular dynamics the primary nucleation process of 12 Aβ peptides and investigate the effects of CU on the process. We found that CU molecules intercalate among the Aβ chains and bind tightly to them by hydrogen bonds, hydrophobic, π–π, and cation–π interactions. In the presence of CU, the Aβ peptides form a primary nucleus of a bigger size. The peptide chains in the nucleus become less flexible and more disordered, and the number of non-native contacts and hydrogen bonds between them decreases. For comparison, the effects of the weaker Aβ inhibitor ferulic acid (FA) on the primary nucleation are also examined. Our study is in good agreement with the observation that taken regularly, CU is able to prevent or at least delay the onset of neurodegenerative disorders.

Influence of Agitation and Fluid Shear on Primary Nucleation in Solution

2013 ◽  
Vol 13 (10) ◽  
pp. 4385-4394 ◽  
Author(s):  
Jin Liu ◽  
Åke C. Rasmuson
Keyword(s):  
Fluid Shear ◽  
Primary Nucleation

Heterogeneous primary nucleation of ice in water and aqueous solutions

1968 ◽  
Vol 3-4 ◽  
pp. 355-359 ◽  
Author(s):  
H.A.C. Thijssen ◽  
M.A.G. Vorstman ◽  
J.A. Roels
Keyword(s):  
Aqueous Solutions ◽  
Primary Nucleation

scholarly journals Chaperones mainly suppress primary nucleation during formation of functional amyloid required for bacterial biofilm formation

2022 ◽  
Author(s):  
Madhu Nagaraj ◽  
Zahra Najarzadeh ◽  
Jonathan Pansieri ◽  
Ludmilla A. Morozova-Roche ◽  
Henrik Biverstål ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Functional Amyloid ◽  
E Coli ◽  
Primary Nucleation ◽  
Functional Amyloids

Unlike misfolding in neurodegenerative diseases, aggregation of functional amyloids involved in bacterial biofilm, e.g. CsgA (E. coli) and FapC (Pseudomonas), is carefully regulated. However, it is unclear whether functional aggregation...

scholarly journals Interfacial Effects on the Spherulitic Morphology of Isotactic Polystyrene Thin Films on Liquid Substrates

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Takashi Sasaki ◽  
Masaaki Nakagiri ◽  
Satoshi Irie
Keyword(s):  
Thin Films ◽  
Nucleation Rate ◽  
Silicone Oil ◽  
Cold Crystallization ◽  
Number Density ◽  
Interfacial Effects ◽  
Isotactic Polystyrene ◽  
Primary Nucleation ◽  
Atactic Polystyrene ◽  
Spherulite Morphology

The influence of interfaces on the morphology of flat spherulites of isotactic polystyrene (iPS) grown in thin films on liquid substrates was investigated. Amorphous iPS thin films spin-cast from a solution were annealed for cold crystallization on glycerol and silicone oil (nonsolvents for iPS). The number density of grown spherulites was revealed to be higher on the glycerol substrate than on the silicone oil substrate. This implies that the primary nucleation rate of crystallization is greater at the iPS/glycerol interface than at the iPS/silicone oil interface. The results may be consistent with the previous findings that concern the molecular interaction between atactic polystyrene and nonsolvents at the interface. In some cases, holes were formed in the thin films during the cold crystallization due to dewetting, which also significantly affect the spherulite morphology via, for example, transcrystallization.

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