scholarly journals Supplementary material to "Application of holography and automated image processing for laboratory experiments on mass and fall speed of small cloud ice crystals"

2020 ◽  
Author(s):  
Maximilian Weitzel ◽  
Subir K. Mitra ◽  
Miklós Szakáll ◽  
Jacob P. Fugal ◽  
Stephan Borrmann
Keyword(s):  
Image Processing ◽  
Laboratory Experiments ◽  
Ice Crystals ◽  
Supplementary Material ◽  
Fall Speed ◽  
Cloud Ice ◽  
Automated Image Processing ◽  
Small Cloud

scholarly journals Application of holography and automated image processing for laboratory experiments on mass and fall speed of small cloud ice crystals

2020 ◽  
Vol 20 (23) ◽  
pp. 14889-14901
Author(s):  
Maximilian Weitzel ◽  
Subir K. Mitra ◽  
Miklós Szakáll ◽  
Jacob P. Fugal ◽  
Stephan Borrmann
Keyword(s):  
Three Dimensional ◽  
Ice Crystals ◽  
Local Cooling ◽  
Ice Cloud ◽  
Before And After ◽  
Data Points ◽  
Melting Crystal ◽  
Cloud Ice ◽  
Automated Image Processing ◽  
The Relationship

Abstract. An ice cloud chamber was developed at the Johannes Gutenberg University of Mainz for generating several thousand data points for mass and sedimentation velocity measurements of ice crystals with sizes less than 150 µm. Ice nucleation was initiated from a cloud of supercooled droplets by local cooling using a liquid nitrogen cold finger. Three-dimensional tracks of ice crystals falling through the slightly supersaturated environment were obtained from the reconstruction of sequential holographic images, automated detection of the crystals in the hologram reconstructions, and particle tracking. Through collection of the crystals and investigation under a microscope before and after melting, crystal mass was determined as a function of size. The experimentally obtained mass versus diameter (m(D)) power law relationship resulted in lower masses for small ice crystals than from commonly adopted parameterizations. Thus, they did not support the currently accepted extrapolation of relationships measured for larger crystal sizes. The relationship between Best (X) and Reynolds (Re) numbers for columnar crystals was found to be X=15.3 Re1.2, which is in general agreement with literature parameterizations.

scholarly journals Application of holography and automated image processing for laboratory experiments on mass and fall speed of small cloud ice crystals

2020 ◽  
Author(s):  
Maximilian Weitzel ◽  
Subir K. Mitra ◽  
Miklós Szakáll ◽  
Jacob P. Fugal ◽  
Stephan Borrmann
Keyword(s):  
Three Dimensional ◽  
Ice Crystals ◽  
Local Cooling ◽  
Ice Cloud ◽  
Before And After ◽  
Data Points ◽  
Melting Crystal ◽  
Cloud Ice ◽  
Automated Image Processing ◽  
The Relationship

Abstract. An ice cloud chamber was developed at the Johannes Gutenberg University of Mainz for generating several thousand data points for mass and sedimentation velocity measurements of ice crystals with sizes less than 150 μm. Ice nucleation was initiated from a cloud of supercooled droplets by local cooling using a liquid nitrogen cold finger. Three-dimensional tracks of ice crystals falling through the slightly supersaturated environment were obtained from the reconstruction of sequential holographic images, automated detection of the crystals in the hologram reconstructions, and particle tracking. Through collection of the crystals and investigation under a microscope before and after melting, crystal mass was determined as a function of size. The experimentally obtained mass versus diameter (m(D)) power law relationship resulted in lower masses for small ice crystals than from commonly adopted parameterizations. Thus, they did not support the currently accepted extrapolation of relationships measured for larger crystal sizes. The relationship between Best (X) and Reynolds (Re) numbers for columnar crystals was found to be X = 15.3Re1.2, which is in general agreement with literature parameterizations.

scholarly journals Influence of the ice growth rate on the incorporation of gaseous HCl

2004 ◽  
Vol 4 (11/12) ◽  
pp. 2513-2519 ◽  
Author(s):  
F. Domine ◽  
C. Rauzy
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Growth Mechanism ◽  
Laboratory Experiments ◽  
Ice Crystals ◽  
Ice Growth ◽  
A Value ◽  
Physical Variables ◽  
Hcl Concentration ◽  
Cloud Ice

Abstract. Ice crystals were grown in the laboratory at −15°C, at different growth rates and in the presence of a partial pressure of HCl of 1.63×10-3 Pa, to test whether the ice growth rate influences the amount of HCl taken up, XHCl, as predicted by the ice growth mechanism of Domine and Thibert (1996). The plot of HCl concentration in ice as a function of growth rate has the aspect predicted by that mechanism: XHCl decreases with increasing growth rate, from a value that depends on thermodynamic equilibrium to a value that depends only on kinetic factors. The height of the growth steps of the ice crystals is determined to be about 150 nm from these experiments. We discuss that the application of these laboratory experiments to cloud ice crystals and to snow metamorphism is not quantitatively possible at this stage, because the physical variables that determine crystal growth in nature, and in particular the step height, are not known. Qualitative applications are attempted for HCl and HNO3 incorporation in cloud ice and snowpack crystals.

scholarly journals Influence of the ice growth rate on the incorporation of gaseous HCl

2004 ◽  
Vol 4 (4) ◽  
pp. 4719-4736 ◽  
Author(s):  
F. Domine ◽  
C. Rauzy
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Growth Mechanism ◽  
Laboratory Experiments ◽  
Ice Crystals ◽  
Ice Growth ◽  
A Value ◽  
Physical Variables ◽  
Hcl Concentration ◽  
Cloud Ice

Abstract. Ice crystals were grown in the laboratory at −15°C, at different growth rates and in the presence of a partial pressure of HCl of 1.63×10−3 Pa, to test whether the ice growth rate influences the amount of HCl taken up, XHCl, as predicted by the ice growth mechanism of Domine and Thibert (1996). The plot of HCl concentration in ice as a function of growth rate has the aspect predicted by that mechanism: XHCl decreases with increasing growth rate, from a value that depends on thermodynamic equilibrium to a value that depends only on kinetic factors. The height of the growth steps of the ice crystals is determined to be about 1.5 nm from these experiments. We discuss that the application of these laboratory experiments to cloud ice crystals and to snow metamorphism is not quantitatively possible at this stage, because the physical variables that determine crystal growth in nature, and in particular the step height, are not known. Qualitative applications are attempted for HCl and HNO3 incorporation in cloud ice and snowpack crystals.

scholarly journals Crystal Orientation in Glacier and in Experimentally Deformed Ice

1960 ◽  
Vol 3 (27) ◽  
pp. 589-606 ◽  
Author(s):  
George P. Rigsby
Keyword(s):  
Crystal Orientation ◽  
Laboratory Experiments ◽  
Ice Crystals ◽  
Equal Area ◽  
Fine Grained ◽  
Planar Structures ◽  
Glacier Ice ◽  
Glacier Flow ◽  
High Shearing ◽  
Universal Stage

AbstractMore than 8,000 ice crystals have been oriented and measured for crystal fabric studies from widely separated temperate and polar glaciers, using a large universal stage and thin-section techniques. Very strong fabrics have been found and a number of laboratory experiments on deformation and recrystallization of ice were conducted in an attempt to solve some of the perplexing problems raised concerning glacier flow.In polar glaciers the c or optic axes of the ice crystals tend to be perpendicular to the foliation plane (alternating planar structures of bubbly and clear ice). In areas of high shearing stress the preferred orientation of the axes reached 39 per cent in 1 per cent of the area when plotted on a Schmidt equal-area projection. In temperate glaciers the optic axes tend to form three or four strong maxima which also appear related to the foliation.Patterns from ice deformed in the laboratory resemble some of the fabric patterns found in polar glaciers. During deformation of laboratory specimens, large crystals have been observed recrystallizing into many smaller ones, while fine-grained ice, after completion of deformation (both glacier ice and laboratory deformed ice), has been annealed at melting temperature into a few large crystals with different orientations from the original pattern.

scholarly journals Simulating the influence of primary biological aerosol particles on clouds by heterogeneous ice nucleation

2018 ◽  
Vol 18 (20) ◽  
pp. 15437-15450 ◽  
Author(s):  
Matthias Hummel ◽  
Corinna Hoose ◽  
Bernhard Pummer ◽  
Caroline Schaupp ◽  
Janine Fröhlich-Nowoisky ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Ice Crystals ◽  
Atmospheric Measurements ◽  
Cloud Ice ◽  
Biological Aerosol Particles ◽  
Ice Phase ◽  
Heterogeneous Ice Nucleation

Abstract. Primary ice formation, which is an important process for mixed-phase clouds with an impact on their lifetime, radiative balance, and hence the climate, strongly depends on the availability of ice-nucleating particles (INPs). Supercooled droplets within these clouds remain liquid until an INP immersed in or colliding with the droplet reaches its activation temperature. Only a few aerosol particles are acting as INPs and the freezing efficiency varies among them. Thus, the fraction of supercooled water in the cloud depends on the specific properties and concentrations of the INPs. Primary biological aerosol particles (PBAPs) have been identified as very efficient INPs at high subzero temperatures, but their very low atmospheric concentrations make it difficult to quantify their impact on clouds. Here we use the regional atmospheric model COSMO–ART to simulate the heterogeneous ice nucleation by PBAPs during a 1-week case study on a domain covering Europe. We focus on three highly ice-nucleation-active PBAP species, Pseudomonas syringae bacteria cells and spores from the fungi Cladosporium sp. and Mortierella alpina. PBAP emissions are parameterized in order to represent the entirety of bacteria and fungal spores in the atmosphere. Thus, only parts of the simulated PBAPs are assumed to act as INPs. The ice nucleation parameterizations are specific for the three selected species and are based on a deterministic approach. The PBAP concentrations simulated in this study are within the range of previously reported results from other modeling studies and atmospheric measurements. Two regimes of PBAP INP concentrations are identified: a temperature-limited and a PBAP-limited regime, which occur at temperatures above and below a maximal concentration at around −10 ∘C, respectively. In an ensemble of control and disturbed simulations, the change in the average ice crystal concentration by biological INPs is not statistically significant, suggesting that PBAPs have no significant influence on the average state of the cloud ice phase. However, if the cloud top temperature is below −15 ∘C, PBAP can influence the cloud ice phase and produce ice crystals in the absence of other INPs. Nevertheless, the number of produced ice crystals is very low and it has no influence on the modeled number of cloud droplets and hence the cloud structure.

scholarly journals Ранняя диагностика меланомы кожи с применением нескольких изображающих систем

2020 ◽  
Vol 128 (6) ◽  
pp. 820
Author(s):  
К.Г. Кудрин ◽  
Е.Н. Римская ◽  
И.А. Аполлонова ◽  
А.П. Николаев ◽  
Н.В. Черномырдин ◽  
...  
Keyword(s):  
Image Processing ◽  
Measurement Errors ◽  
Skin Neoplasms ◽  
Imaging Systems ◽  
Clinical Parameters ◽  
Skin Melanoma ◽  
Clinical Images ◽  
Melanoma Diagnosis ◽  
Complex Approach ◽  
Automated Image Processing

A complex approach to the early diagnosis of skin melanoma has been proposed. The approach involves a step-by-step examination of pigment tumors using several imaging systems. The features of morphometry of clinical images of pigmented skin neoplasms, features of imaging systems, the main stages of automated image processing and pattern recognition in the melanoma diagnosis has been considered. The metrological features of the proposed approach has been shown: the measurement errors of the clinical parameters of skin neoplasms by the proposed methods do not exceed the allowable errors. The approbation of the offered approach has been showed that sensitivity and specificity of the used methods exceeds 90%

scholarly journals Automated Image Processing to Quantify Cell Migration

2013 ◽  
pp. 152-157 ◽  
Author(s):  
Minmin Shen ◽  
Bastian Zimmer ◽  
Marcel Leist ◽  
Dorit Merhof
Keyword(s):  
Image Processing ◽  
Cell Migration ◽  
Automated Image Processing
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