Microscopic Pattern of Ice Crystal Growth in the Presence of Thermal Hysteresis Proteins

1994 ◽  
Vol 116 (3) ◽  
pp. 173-179 ◽  
Author(s):  
R. Coger ◽  
B. Rubinsky ◽  
G. Fletcher
Keyword(s):  
Crystal Growth ◽  
Thermal Hysteresis ◽  
Phase Interface ◽  
Supercooled Liquid ◽  
Hexagonal Prism ◽  
Ice Crystal ◽  
Two Phase ◽  
Ice Water ◽  
Solidification Stage ◽  
Thermal Hysteresis Proteins

This study examines the effect of thermal hysteresis proteins (THPs) from the winter flounder (Psuedopleuronectes americanus) on the ice-water interface morphology during freezing of aqueous solutions. Experiments were performed using a directional solidification stage, and the development of the two-phase interface was observed through a microscope and recorded by a video system. Unusual ice crystal morphologies were observed, including faceted ice crystal growth along the [1100] crystal plane; spicular or needlelike growth in the [1010] direction; and growth parallel to the c-axis, [0001], consisting of incorporated liquid inclusions bounded by hexagonal prism faces. The observed crystallographic structures can be explained as an effect of the interaction between the THPs and the primary prism faces of ice crystals. This results in an increase in the Gibbs free energy of these planes, followed by ice growth into the supercooled liquid adjacent to these faces.

scholarly journals Ice Growth Acceleration by Antifreeze Proteins Leads to Higher Thermal Hysteresis Activity

2020 ◽  
Author(s):  
Jinzi Deng ◽  
Elana Apfelbaum ◽  
Ran Drori
Keyword(s):  
Crystal Growth ◽  
Growth Inhibition ◽  
Growth Velocity ◽  
Crystal Morphology ◽  
Thermal Hysteresis ◽  
Antifreeze Proteins ◽  
Ice Crystal ◽  
Ice Growth ◽  
Thermal Hysteresis Activity ◽  
Adsorption Rates

<p>Since some antifreeze proteins and glycoproteins (AF(G)Ps) cannot directly bind to all crystal planes, they change ice crystal morphology by minimizing the area of the crystal planes to which they cannot bind until crystal growth is halted. Previous studies found that growth along the <i>c</i>-axis (perpendicular to the basal plane, the crystal plane to which these AF(G)Ps cannot bind) is accelerated by some AF(G)Ps, while growth of other planes is inhibited. The effects of this growth acceleration on crystal morphology and on the thermal hysteresis activity are unknown to date. Understanding these effects will elucidate the mechanism of ice growth inhibition by AF(G)Ps. Using cold stages and an Infrared laser, ice growth velocities and crystal morphologies in AF(G)P solutions were measured. Three types of effects on growth velocity were found: concentration-dependent acceleration, concentration-independent acceleration, and concentration-dependent deceleration. Quantitative crystal morphology measurements in AF(G)P solutions demonstrated that adsorption rate of the proteins to ice plays a major role in determining the morphology of the bipyramidal crystal. These results demonstrate that faster adsorption rates generate bipyramidal crystals with diminished basal surfaces at higher temperatures compared to slower adsorption rates. The acceleration of growth along the <i>c</i>-axis generates crystals with smaller basal surfaces at higher temperatures leading to increased growth inhibition of the entire crystal.<a></a></p>

scholarly journals Observations of the Origin and Distribution of Ice in Cold, Warm, and Occluded Frontal Systems during the DIAMET Campaign

2014 ◽  
Vol 142 (11) ◽  
pp. 4230-4255 ◽  
Author(s):  
G. Lloyd ◽  
C. Dearden ◽  
T. W. Choularton ◽  
J. Crosier ◽  
K. N. Bower
Keyword(s):  
Case Studies ◽  
Cold Front ◽  
Supercooled Liquid ◽  
Ice Nucleation ◽  
Ice Crystal ◽  
Atmospheric Measurements ◽  
Radar Satellite ◽  
Cloud Tops ◽  
Ice Water ◽  
Water Contents

Abstract Three case studies in frontal clouds from the Diabatic Influences on Mesoscale Structures in Extratropical Storms (DIAMET) project are described to understand the microphysical development of the mixed phase regions of these clouds. The cases are a kata-type cold front, a wintertime warm front, and a summertime occluded frontal system. The clouds were observed by radar, satellite, and in situ microphysics measurements from the U.K. Facility for Airborne Atmospheric Measurements (FAAM) research aircraft. The kata cold front cloud was shallow with a cloud-top temperature of approximately −13°C. Cloud-top heterogeneous ice nucleation was found to be consistent with predictions by a primary ice nucleation scheme. The other case studies had high cloud tops (&lt; −40°C) and despite no direct cloud-top measurements in these regions, homogeneous ice nucleation would be expected. The maximum ice crystal concentrations and ice water contents in all clouds were observed at temperatures around −5°C. Graupel was not observed, hence, secondary ice was produced by riming on snow falling through regions of supercooled liquid water. Within these regions substantial concentrations (10–150 L−1) of supercooled drizzle were observed. The freezing of these drops increases the riming rate due to the increase in rimer surface area. Increasing rime accretion has been shown to lead to higher ice splinter production rates. Despite differences in the cloud structure, the maximum ice crystal number concentration in all three clouds was ~100 L−1. Ice water contents were similar in the warm and occluded frontal cases, where median values in both cases reached ~0.2–0.3 g m−3, but lower in the cold front case.

scholarly journals Ice Growth Acceleration by Antifreeze Proteins Leads to Higher Thermal Hysteresis Activity

2020 ◽  
Author(s):  
Jinzi Deng ◽  
Elana Apfelbaum ◽  
Ran Drori
Keyword(s):  
Crystal Growth ◽  
Growth Inhibition ◽  
Growth Velocity ◽  
Crystal Morphology ◽  
Thermal Hysteresis ◽  
Antifreeze Proteins ◽  
Ice Crystal ◽  
Ice Growth ◽  
Thermal Hysteresis Activity ◽  
Adsorption Rates

<p>Since some antifreeze proteins and glycoproteins (AF(G)Ps) cannot directly bind to all crystal planes, they change ice crystal morphology by minimizing the area of the crystal planes to which they cannot bind until crystal growth is halted. Previous studies found that growth along the <i>c</i>-axis (perpendicular to the basal plane, the crystal plane to which these AF(G)Ps cannot bind) is accelerated by some AF(G)Ps, while growth of other planes is inhibited. The effects of this growth acceleration on crystal morphology and on the thermal hysteresis activity are unknown to date. Understanding these effects will elucidate the mechanism of ice growth inhibition by AF(G)Ps. Using cold stages and an Infrared laser, ice growth velocities and crystal morphologies in AF(G)P solutions were measured. Three types of effects on growth velocity were found: concentration-dependent acceleration, concentration-independent acceleration, and concentration-dependent deceleration. Quantitative crystal morphology measurements in AF(G)P solutions demonstrated that adsorption rate of the proteins to ice plays a major role in determining the morphology of the bipyramidal crystal. These results demonstrate that faster adsorption rates generate bipyramidal crystals with diminished basal surfaces at higher temperatures compared to slower adsorption rates. The acceleration of growth along the <i>c</i>-axis generates crystals with smaller basal surfaces at higher temperatures leading to increased growth inhibition of the entire crystal.<a></a></p>

scholarly journals Correlation between Microstructure and Hydrogen Degradation of 690 MPa Grade Marine Engineering Steel

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 851
Author(s):  
Heng Ma ◽  
Huiyun Tian ◽  
Juncheng Xin ◽  
Zhongyu Cui
Keyword(s):  
Crack Propagation ◽  
Base Metal ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Steel Substrate ◽  
Phase Interface ◽  
Grain Structure ◽  
Hydrogen Degradation ◽  
Two Phase ◽  
Annealed Steel

Electrochemical H charging, hydrogen permeation, and hydrogen-induced cracking (HIC) behavior of 690 MPa grade steel substrate and different heat-treatment states (annealed, quenched, normalized, tempered) are investigated by cyclic voltammetry (CV), hydrogen permeation, electrochemical H charging, and slow strain rate tensile test (SSRT). The results show that hydrogen diffuses through the steel with the highest rate in base metal and the lowest rate in annealed steel. The hydrogen-induced cracks in base metal show obvious step shape with tiny cracks near the main crack. The cracks of annealed steel are mainly distributed along pearlite. The crack propagation of quenched steel is mainly transgranular, while the hydrogen-induced crack propagation of tempered steel is along the prior austenite grain boundary. HIC sensitivity of base metal is the lowest due to its fine homogeneous grain structure, small hydrogen diffusion coefficient, and small hydrogen diffusion rate. There are many hydrogen traps in annealed steel, such as the two-phase interface which provides accommodation sites for H atoms and increases the HIC susceptibility.

The Mystery of Ice Crystal Multiplication in a Laboratory Experiment

2013 ◽  
Vol 71 (1) ◽  
pp. 89-97 ◽  
Author(s):  
Gianni Santachiara ◽  
Franco Belosi ◽  
Franco Prodi
Keyword(s):  
Laboratory Experiment ◽  
Supercooled Liquid ◽  
Ice Crystals ◽  
Formation Processes ◽  
Ice Crystal ◽  
Droplet Vaporization ◽  
Ice Nuclei ◽  
Cold Room ◽  
The Mean ◽  
Ice Multiplication

Abstract This paper addresses the problem of the large discrepancies between ice crystal concentrations in clouds and the number of ice nuclei in nearby clear air reported in published papers. Such discrepancies cannot always be explained, even by taking into account both primary and secondary ice formation processes. A laboratory experiment was performed in a cylindrical column placed in a cold room at atmospheric pressure and temperature in the −12° to −14°C range. Supercooled droplets were nucleated in the column, in the absence of aerosol ice nuclei, by injecting ice crystals generated outside in a small syringe. A rapid increase in the ice crystal concentration was observed in the absence of any known ice multiplication. The ratio between the mean number of ice crystals in the column, after complete droplet vaporization, and the number of ice crystals introduced in the column was about 10:1. The presence of small ice crystals (introduced at the top of the column) in the unstable system (supercooled droplets) appears to trigger the transformation in the whole supercooled liquid cloud. A possible explanation could be that the rapidly evaporating droplets cool sufficiently to determine a homogeneous nucleation.

scholarly journals Synthetic insect antifreeze peptides modify ice crystal growth habit

CrystEngComm ◽  
2017 ◽  
Vol 19 (16) ◽  
pp. 2163-2167 ◽  
Author(s):  
Charles H. Z. Kong ◽  
Ivanhoe K. H. Leung ◽  
Vijayalekshmi Sarojini
Keyword(s):  
Crystal Growth ◽  
Small Molecule ◽  
Growth Habit ◽  
Antifreeze Protein ◽  
Ice Crystals ◽  
Ice Crystal ◽  
Antifreeze Peptides ◽  
Antifreeze Activity

Synthetic antifreeze peptides based on the hyperactive antifreeze protein modify the shape of ice crystals and show enhanced antifreeze activity with the addition of a small molecule.

Modeling of Vapor Compression Cycles for Multivariable Feedback Control of HVAC Systems

1997 ◽  
Vol 119 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Xiang-Dong He ◽  
Sheng Liu ◽  
Haruhiko H. Asada
Keyword(s):  
Feedback Control ◽  
Phase Interface ◽  
Heat Pumps ◽  
Lumped Parameter Model ◽  
Vapor Compression ◽  
Two Phase ◽  
Lumped Parameter ◽  
Fan Speed ◽  
Linearized Model ◽  
Multivariable Feedback

This paper presents a new lumped-parameter model for describing the dynamics of vapor compression cycles. In particular, the dynamics associated with the two heat exchangers, i.e., the evaporator and the condenser, are modeled based on a moving-interface approach by which the position of the two-phase/single-phase interface inside the one-dimensional heat exchanger can be properly predicted. This interface information has never been included in previous lumped-parameter models developed for control design purpose, although it is essential in predicting the refrigerant superheat or subcool value. This model relates critical performance outputs, such as evaporating pressure, condensing pressure, and the refrigerant superheat, to actuating inputs including compressor speed, fan speed, and expansion valve opening. The dominating dynamic characteristics of the cycle around an operating point is studied based on the linearized model. From the resultant transfer function matrix, an interaction measure based on the Relative Gain Array reveals strong cross-couplings between various input-output pairs, and therefore indicates the inadequacy of independent SISO control techniques. In view of regulating multiple performance outputs in modern heat pumps and air-conditioning systems, this model is highly useful for design of multivariable feedback control.

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