Homogeneous ice nucleation rate at negative pressures: The role of the density anomaly

2021 ◽  
pp. 139289
Author(s):  
Elise Rosky ◽  
Will Cantrell ◽  
Tianshu Li ◽  
Raymond A. Shaw
Keyword(s):  
Nucleation Rate ◽  
Ice Nucleation ◽  
Density Anomaly ◽  
Negative Pressures

scholarly journals Study of Nucleation and Growth in the Organometallic Synthesis of Magnetic Alloy Nanocrystals: The Role of Nucleation Rate in Size Control of CoPt3 Nanocrystals.

ChemInform ◽  
2003 ◽  
Vol 34 (42) ◽  
Author(s):  
Elena V. Shevchenko ◽  
Dmitri V. Talapin ◽  
Heimo Schnablegger ◽  
Andreas Kornowski ◽  
Oerjan Festin ◽  
...  
Keyword(s):  
Nucleation Rate ◽  
Size Control ◽  
Nucleation And Growth ◽  
Magnetic Alloy ◽  
Organometallic Synthesis ◽  
Alloy Nanocrystals

scholarly journals Role of Salt, Pressure, and Water Activity on Homogeneous Ice Nucleation

2017 ◽  
Vol 8 (18) ◽  
pp. 4486-4491 ◽  
Author(s):  
Jorge R. Espinosa ◽  
Guiomar D. Soria ◽  
Jorge Ramirez ◽  
Chantal Valeriani ◽  
Carlos Vega ◽  
...  
Keyword(s):  
Water Activity ◽  
Ice Nucleation

scholarly journals Analysis of the effect of water activity on ice formation using a new thermodynamic framework

2014 ◽  
Vol 14 (14) ◽  
pp. 7665-7680 ◽  
Author(s):  
D. Barahona
Keyword(s):  
Water Activity ◽  
Nucleation Rate ◽  
Ice Nucleation ◽  
Nucleation Theory ◽  
Cloud Formation ◽  
Classical Nucleation Theory ◽  
Solid Matrix ◽  
Effect Of Water ◽  
Thermodynamic Framework ◽  
New Framework

Abstract. In this work a new thermodynamic framework is developed and used to investigate the effect of water activity on the formation of ice within supercooled droplets. The new framework is based on a novel concept where the interface is assumed to be made of liquid molecules "trapped" by the solid matrix. It also accounts for the change in the composition of the liquid phase upon nucleation. Using this framework, new expressions are developed for the critical ice germ size and the nucleation work with explicit dependencies on temperature and water activity. However unlike previous approaches, the new model does not depend on the interfacial tension between liquid and ice. The thermodynamic framework is introduced within classical nucleation theory to study the effect of water activity on the ice nucleation rate. Comparison against experimental results shows that the new approach is able to reproduce the observed effect of water activity on the nucleation rate and the freezing temperature. It allows for the first time a phenomenological derivation of the constant shift in water activity between melting and nucleation. The new framework offers a consistent thermodynamic view of ice nucleation, simple enough to be applied in atmospheric models of cloud formation.

scholarly journals Sensorimotor function of the upper-airway muscles and respiratory sensory processing in untreated obstructive sleep apnea

2011 ◽  
Vol 111 (6) ◽  
pp. 1644-1653 ◽  
Author(s):  
Danny J. Eckert ◽  
Yu L. Lo ◽  
Julian P. Saboisky ◽  
Amy S. Jordan ◽  
David P. White ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Disease Progression ◽  
Sensory Processing ◽  
Upper Airway ◽  
Lung Ventilation ◽  
Tongue Protrusion ◽  
Obstructive Sleep ◽  
Sensorimotor Impairment ◽  
Negative Pressures

Numerous studies have demonstrated upper-airway neuromuscular abnormalities during wakefulness in snorers and obstructive sleep apnea (OSA) patients. However, the functional role of sensorimotor impairment in OSA pathogenesis/disease progression and its potential effects on protective upper-airway reflexes, measures of respiratory sensory processing, and force characteristics remain unclear. This study aimed to gain physiological insight into the potential role of sensorimotor impairment in OSA pathogenesis/disease progression by comparing sensory processing properties (respiratory-related evoked potentials; RREP), functionally important protective reflexes (genioglossus and tensor palatini) across a range of negative pressures (brief pulses and entrained iron lung ventilation), and tongue force and time to task failure characteristics between 12 untreated OSA patients and 13 controls. We hypothesized that abnormalities in these measures would be present in OSA patients. Upper-airway reflexes (e.g., genioglossus onset latency, 20 ± 1 vs. 19 ± 2 ms, P = 0.82), early RREP components (e.g., P1 latency 25 ± 2 vs. 25 ± 1 ms, P = 0.78), and the slope of epiglottic pressure vs. genioglossus activity during iron lung ventilation (−0.68 ± 1.0 vs. −0.80 ± 2.0 cmH2O/%max, P = 0.59) were not different between patients and controls. Maximal tongue protrusion force was greater in OSA patients vs. controls (35 ± 2 vs. 27 ± 2 N, P < 0.01), but task failure occurred more rapidly (149 ± 24 vs. 254 ± 23 s, P < 0.01). Upper-airway protective reflexes across a range of negative pressures as measured by electromyography and the early P1 component of the RREP are preserved in OSA patients during wakefulness. Consistent with an adaptive training effect, tongue protrusion force is increased, not decreased, in untreated OSA patients. However, OSA patients may be vulnerable to fatigue of upper-airway dilator muscles, which could contribute to disease progression.

scholarly journals Homogeneous Ice Nucleation Rate in Water Droplets

2018 ◽  
Vol 122 (40) ◽  
pp. 22892-22896 ◽  
Author(s):  
Jorge R. Espinosa ◽  
Carlos Vega ◽  
Eduardo Sanz
Keyword(s):  
Nucleation Rate ◽  
Ice Nucleation ◽  
Water Droplets

scholarly journals The clavobranchialis musculature in sarcopterygian fishes, and contribution to osteichthyan feeding and respiration

2003 ◽  
Vol 72 (1) ◽  
pp. 17-37 ◽  
Author(s):  
Zerina Johanson
Keyword(s):  
Oral Cavity ◽  
Negative Pressure ◽  
Ventral Surface ◽  
Pectoral Girdle ◽  
Gill Chamber ◽  
Bony Fishes ◽  
Oropharyngeal Cavity ◽  
Actinopterygian Fishes ◽  
Negative Pressures

Various fossil lungfish taxa preserve distinct depressions on the smooth postbranchial lamina of the dermal pectoral girdle. These depressions are largely unknown in other sarcopterygian fishes, but are present in the rhizodont sarcopterygian Strepsodus. Comparisons with extant actinopterygian fishes suggest these depressions mark the point of origin for the clavobranchialis musculature, extending anterodorsally into the gill chamber to insert on the ventral surface of the ceratobranchial(s). Studios examining feeding and respiratory mechanisms of bony fishes (Osteichthyes) have emphasised the role of mandibular depression in generating negative pressures within the oral cavity to draw in water/air/food via suction. However, phylogenetically basal actinopterygians, fossil lungfish and other fossil sarcopterygians (such as Strepsodus) lack the apomorphies that increase suction among bony fishes. In these taxa the clavobranchialis muscles may serve to augment this negative pressure by retracting the ceratobranchials and increasing the size of the oral/ oropharyngeal cavity. A comparable action is performed by the chondrichthyan coracobranchiales muscles, particularly during feeding, and the function of these ventral gill arch muscles is likely to be a synapomorphy of jawed vertebrates (Gnathostomata). This musculature is absent from jawless vertebrates such as the Osteostraci.

scholarly journals Ice is born in low-mobility regions of supercooled liquid water

2019 ◽  
Vol 116 (6) ◽  
pp. 2009-2014 ◽  
Author(s):  
Martin Fitzner ◽  
Gabriele C. Sosso ◽  
Stephen J. Cox ◽  
Angelos Michaelides
Keyword(s):  
Liquid Water ◽  
Dynamical Behavior ◽  
Supercooled Liquid ◽  
Ice Nucleation ◽  
Water Molecules ◽  
Ice Crystal ◽  
Surrounding Water ◽  
Dynamical Heterogeneity ◽  
Complex Dynamical Behavior

When an ice crystal is born from liquid water, two key changes occur: (i) The molecules order and (ii) the mobility of the molecules drops as they adopt their lattice positions. Most research on ice nucleation (and crystallization in general) has focused on understanding the former with less attention paid to the latter. However, supercooled water exhibits fascinating and complex dynamical behavior, most notably dynamical heterogeneity (DH), a phenomenon where spatially separated domains of relatively mobile and immobile particles coexist. Strikingly, the microscopic connection between the DH of water and the nucleation of ice has yet to be unraveled directly at the molecular level. Here we tackle this issue via computer simulations which reveal that (i) ice nucleation occurs in low-mobility regions of the liquid, (ii) there is a dynamical incubation period in which the mobility of the molecules drops before any ice-like ordering, and (iii) ice-like clusters cause arrested dynamics in surrounding water molecules. With this we establish a clear connection between dynamics and nucleation. We anticipate that our findings will pave the way for the examination of the role of dynamical heterogeneities in heterogeneous and solution-based nucleation.

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