A New Methodology for the Statistical Descriptions of Particle‐by‐Particle Measurements of Liquid Droplets in Cumulus Clouds

2021 ◽  
Author(s):  
Sudarsan Bera ◽  
Subharthi Chowdhuri ◽  
Thara V. Prabha
Keyword(s):  
Liquid Droplets ◽  
Cumulus Clouds ◽  
Particle Measurements

scholarly journals Modeling Study of Ice Formation in Warm-Based Precipitating Shallow Cumulus Clouds

2012 ◽  
Vol 69 (11) ◽  
pp. 3315-3335 ◽  
Author(s):  
Jiming Sun ◽  
Parisa A. Ariya ◽  
Henry G. Leighton ◽  
Man Kong Yau
Keyword(s):  
Cloud Model ◽  
Cloud Condensation Nuclei ◽  
Interaction Model ◽  
Convective Cloud ◽  
Liquid Droplets ◽  
Condensation Nuclei ◽  
Cumulus Clouds ◽  
Ice Nuclei ◽  
Shallow Cumulus ◽  
Ice Particles

Abstract Observations of large concentrations of ice particles in the dissipating stage of warm-based precipitating shallow cumulus clouds point to the limitations of scientists’ understanding of the physics of such clouds and the possible role of cloud dynamics. The most commonly accepted mechanisms of ice splinter production in the riming process have limitations to properly explain the rapid production of ice bursts. A more detailed description of the temporal and spatial evolution of hydrometeors and their interaction with cloud condensation nuclei and ice nuclei is needed to understand this phenomenon. A cloud model with bin-resolved microphysics can describe the time-dependent evolution of liquid droplets and ice particles and provide insights into how the physics and dynamics and their interaction may result in ice initiation and ice multiplication. The authors developed a 1.5-dimensional nonhydrostatic convective cloud and aerosol interaction model with spectral (bin) microphysics. The number and mass concentrations of aerosols, including ice nuclei and cloud condensation nuclei, were explicitly followed. Since both in situ observations of bioaerosols and laboratory experiments pointed to efficient nucleation capabilities at relative warm temperatures, it was assumed that ice-nucleating bioaerosols are involved in primary ice particle formation in condensation and immersion modes. Results show that bioaerosols can be the source of primary ice pellets, which in turn lead to high ice concentrations.

AEM analysis of solidification catalysts in atomized Fe-Ni

1986 ◽  
Vol 44 ◽  
pp. 584-585
Author(s):  
Matthew R. Libera
Keyword(s):  
Powder Particle ◽  
Alloy Composition ◽  
Particle Diameter ◽  
Metastable Phases ◽  
Liquid Droplets ◽  
Nucleation Kinetics ◽  
Ni Alloys ◽  
Nonequilibrium Solidification

The liquid droplets produced by atomization processes are believed to undergo substantial supercooling during solidification, because the catalytic heterogeneities, for statistical reasons, tend to be isolated in the larger droplets. This supercooling can lead to the nucleation of metastable phases. As part of a study on the effect of liquid supercooling on nonequilibrium solidification, three binary Fe-Ni alloys have been produced by conventional argon atomization (Fe-20Ni, Fe-30Ni, and Fe-40Ni). The primary variables in these experiments are: i) the alloy composition; and ii) the powder particle diameter (inversely proportional to supercooling). Of particular interest in this system is the competitive nucleation kinetics between the stable fee and metastable bec phases. Bcc is expected to nucleate preferentially with decreasing %Ni and decreasing particle diameter.

HREM observation of NiO growth on submicron spheres of pure nickel

1989 ◽  
Vol 47 ◽  
pp. 548-549
Author(s):  
C.M. Teng ◽  
T.F. Kelly ◽  
J.P. Zhang ◽  
H.M. Lin ◽  
Y.W. Kim
Keyword(s):  
Nickel Oxide ◽  
Grain Boundaries ◽  
Pure Nickel ◽  
Submicron Particles ◽  
Crystal Formation ◽  
Nickel Wire ◽  
Liquid Droplets ◽  
Oxide Interface ◽  
Nickel Chromium ◽  
Chromium Alloys

Spherical submicron particles of materials produced by electrohydrodynamic (EHD) atomization have been used to study a variety of materials processes including nucleation of alternative crystallization phases in iron-nickel and nickel-chromium alloys, amorphous solidification in submicron droplets of pure metals, and quasi-crystal formation in nickel-chromium alloys. Some experiments on pure nickel, nickel oxide single crystals, the nickel/nickel(II) oxide interface, and grain boundaries in nickel monoxide have been performed by STEM. For these latter studies, HREM is the most direct approach to obtain particle crystal structures at the atomic level. Grain boundaries in nickel oxide have also been investigated by HREM. In this paper, we present preliminary results of HREM observations of NiO growth on submicron spheres of pure nickel.Small particles of pure nickel were prepared by EHD atomization. For the study of pure nickel, 0.5 mm diameter pure nickel wire (99.9975%) is sprayed directly in the EHD process. The liquid droplets solidify in free-flight through a vacuum chamber operated at about 10-7 torr.

scholarly journals A Cloud Microphysics Parameterization for Shallow Cumulus Clouds Based on Lagrangian Cloud Model Simulations

2018 ◽  
Vol 75 (11) ◽  
pp. 4031-4047 ◽  
Author(s):  
Yign Noh ◽  
Donggun Oh ◽  
Fabian Hoffmann ◽  
Siegfried Raasch
Keyword(s):  
Cloud Model ◽  
Cloud Microphysics ◽  
Heaviside Function ◽  
Mixing Ratio ◽  
Cumulus Clouds ◽  
Cloud Droplets ◽  
Shallow Cumulus ◽  
Initial Stage ◽  
Accretion Rates ◽  
The Moment

Abstract Cloud microphysics parameterizations for shallow cumulus clouds are analyzed based on Lagrangian cloud model (LCM) data, focusing on autoconversion and accretion. The autoconversion and accretion rates, A and C, respectively, are calculated directly by capturing the moment of the conversion of individual Lagrangian droplets from cloud droplets to raindrops, and it results in the reproduction of the formulas of A and C for the first time. Comparison with various parameterizations reveals the closest agreement with Tripoli and Cotton, such as and , where and are the mixing ratio and the number concentration of cloud droplets, is the mixing ratio of raindrops, is the threshold volume radius, and H is the Heaviside function. Furthermore, it is found that increases linearly with the dissipation rate and the standard deviation of radius and that decreases rapidly with while disappearing at > 3.5 μm. The LCM also reveals that and increase with time during the period of autoconversion, which helps to suppress the early precipitation by reducing A with smaller and larger in the initial stage. Finally, is found to be affected by the accumulated collisional growth, which determines the drop size distribution.

A THREE-STAGE FREEZING MODEL FOR LIQUID DROPLETS WITH APPLICATIONS TO FOOD SPRAYS

2010 ◽  
Vol 20 (11) ◽  
pp. 1005-1016 ◽  
Author(s):  
Franz X. Tanner ◽  
K. A. Feigl ◽  
E. J. Windhab
Keyword(s):  
Liquid Droplets

scholarly journals Characterization of design grammar of peptides for regulating liquid droplets and aggregates of FUS

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kiyoto Kamagata ◽  
Rika Chiba ◽  
Ichiro Kawahata ◽  
Nanako Iwaki ◽  
Saori Kanbayashi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Electrostatic Interactions ◽  
Amyloid Fibrils ◽  
Droplet Formation ◽  
Liquid Droplets ◽  
Proof Of Concept ◽  
Aggregate Formation ◽  
Fused In Sarcoma ◽  
Dynamics Simulations

AbstractLiquid droplets of aggregation-prone proteins, which become hydrogels or form amyloid fibrils, are a potential target for drug discovery. In this study, we proposed an experiment-guided protocol for characterizing the design grammar of peptides that can regulate droplet formation and aggregation. The protocol essentially involves investigation of 19 amino acid additives and polymerization of the identified amino acids. As a proof of concept, we applied this protocol to fused in sarcoma (FUS). First, we evaluated 19 amino acid additives for an FUS solution and identified Arg and Tyr as suppressors of droplet formation. Molecular dynamics simulations suggested that the Arg additive interacts with specific residues of FUS, thereby inhibiting the cation–π and electrostatic interactions between the FUS molecules. Second, we observed that Arg polymers promote FUS droplet formation, unlike Arg monomers, by bridging the FUS molecules. Third, we found that the Arg additive suppressed solid aggregate formation of FUS, while Arg polymer enhanced it. Finally, we observed that amyloid-forming peptides induced the conversion of FUS droplets to solid aggregates of FUS. The developed protocol could be used for the primary design of peptides controlling liquid droplets and aggregates of proteins.

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