Transient convective structures in a cooled water layer in the presence of a drift flow and a surfactant

2016 ◽  
Vol 28 (2) ◽  
pp. 024101
Author(s):  
V. P. Reutov ◽  
G. V. Rybushkina
Keyword(s):  
Water Layer ◽  
Convective Structures

Optical diagnostics of convective structures induced by non-stationary boundary conditions in a vertical water layer

2018 ◽  
Vol 10 (4) ◽  
pp. 134-144 ◽  
Author(s):  
Yu.N. Dubnishchev ◽  
V.A. Arbuzov ◽  
E.V. Arbuzov ◽  
V.S. Berdnikov ◽  
S.A. Kislytsin ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Optical Diagnostics ◽  
Water Layer ◽  
Stationary Boundary ◽  
Convective Structures

scholarly journals Study of convective structures and phase transition induced in a water layer by non-stationary boundary conditions

2019 ◽  
Vol 1421 ◽  
pp. 012047
Author(s):  
Yu N Dubnishchev ◽  
V A Arbuzov ◽  
E V Arbuzov ◽  
V S Berdnikov ◽  
O S Zolotukhina ◽  
...  
Keyword(s):  
Phase Transition ◽  
Boundary Conditions ◽  
Water Layer ◽  
Stationary Boundary ◽  
Convective Structures

scholarly journals Investigation of convective structures and phase transition induced by non-stationary boundary conditions in a horizontal layer of water

2019 ◽  
Author(s):  
Виталий Арбузов ◽  
Vitaliy Arbuzov ◽  
Эдуард Арбузов ◽  
Eduard Arbuzov ◽  
Владимир Бердников ◽  
...  
Keyword(s):  
Phase Transition ◽  
Boundary Conditions ◽  
Water Layer ◽  
Horizontal Layer ◽  
Temperature Fields ◽  
Special Importance ◽  
Stationary Boundary ◽  
Convective Structures ◽  
Numerical Simulation Methods ◽  
Lower Heat

The evolution of convective structures and the phase transition induced by non-stationary boundary conditions in a horizontal water layer bounded by flat heat-exchange surfaces were studied by shear interferometry and numerical simulation methods. Numerical modeling of the temperature field as a field of isotherms in the mode of monotonous cooling of horizontal walls was performed. The problem of fragmentary reconstruction of hilbertograms and shear interferograms images from a numerical model of the isotherm field was solved. The hydrodynamics of convective currents, the coevolution of temperature fields, interference and Hilbert structures have been modeled and studied taking into account the inversion of water density in the vicinity of the isotherm (+4°C), under conditions of phase transition and growth of the ice layer on the lower heat transfer plane. The simulation was performed using a proprietary software package. The relevance of this kind of research is due to the special importance of convection in geodynamics, physics of the atmosphere and the ocean, in hydrodynamic and thermophysical processes associated with the formation and growth of crystals.

scholarly journals An experimental study of the motion of ice past obstacles by the process of regelation

1976 ◽  
Vol 17 (75) ◽  
pp. 79-98 ◽  
Author(s):  
E. M. Morris
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Cross Sections ◽  
Transition Point ◽  
Water Layer ◽  
Single Object ◽  
Two Systems ◽  
Basal Sliding

AbstractThe results of regelation experiments, in which a single object is pulled through ice, cannot be applied directly to the problem of basal sliding in glaciers because the two systems have different geometries. When the force applied to a single object is small, impurities trapped in the regelation water-layer around the object inhibit the regelation process. At larger forces, above the Drake-Shreve transition point, impurities are shed in a trace behind the object. However, when ice moves over a series of obstacles a trace may exist above and below the transition point. The regelation velocity below the transition point is not reduced by the effect of trapped impurities. In an experiment in which brass cylingerrs of various cross-sections rotate in ice, the ratio between the expected regelation velocity, calculated using the basal-sliding theory of Nye, and the measured regelation velocity is 8±2, both above and below the transition point. The same ratio has been obtained by other workers with wires of similar thermal conductivity above the transition point. Measurements of température differences indicate that supercooling cannot be the main source of the unexpectedly low regelation velocities above the transition point.

scholarly journals On the use of plume models to estimate the flux in volcanic gas plumes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Julia Woitischek ◽  
Nicola Mingotti ◽  
Marie Edmonds ◽  
Andrew W. Woods
Keyword(s):  
Electrochemical Sensors ◽  
Measurement Techniques ◽  
Flux Measurement ◽  
Hydrothermal Systems ◽  
Mount Etna ◽  
Volcanic Gas ◽  
Gas Flux ◽  
Convective Structures ◽  
Video Images ◽  
Villarrica Volcano

AbstractMany of the standard volcanic gas flux measurement approaches involve absorption spectroscopy in combination with wind speed measurements. Here, we present a new method using video images of volcanic plumes to measure the speed of convective structures combined with classical plume theory to estimate volcanic fluxes. We apply the method to a nearly vertical gas plume at Villarrica Volcano, Chile, and a wind-blown gas plume at Mount Etna, Italy. Our estimates of the gas fluxes are consistent in magnitude with previous reported fluxes obtained by spectroscopy and electrochemical sensors for these volcanoes. Compared to conventional gas flux measurement techniques focusing on SO2, our new model also has the potential to be used for sulfur-poor plumes in hydrothermal systems because it estimates the H2O flux.

scholarly journals Mapping barrier island soil moisture using a radiative transfer model of hyperspectral imagery from an unmanned aerial system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rehman S. Eon ◽  
Charles M. Bachmann
Keyword(s):  
Soil Moisture ◽  
Radiative Transfer ◽  
Moisture Content ◽  
Layer Thickness ◽  
Soil Moisture Content ◽  
Hyperspectral Imagery ◽  
Barrier Island ◽  
Water Layer ◽  
Radiative Transfer Model ◽  
Transfer Model

AbstractThe advent of remote sensing from unmanned aerial systems (UAS) has opened the door to more affordable and effective methods of imaging and mapping of surface geophysical properties with many important applications in areas such as coastal zone management, ecology, agriculture, and defense. We describe a study to validate and improve soil moisture content retrieval and mapping from hyperspectral imagery collected by a UAS system. Our approach uses a recently developed model known as the multilayer radiative transfer model of soil reflectance (MARMIT). MARMIT partitions contributions due to water and the sediment surface into equivalent but separate layers and describes these layers using an equivalent slab model formalism. The model water layer thickness along with the fraction of wet surface become parameters that must be optimized in a calibration step, with extinction due to water absorption being applied in the model based on equivalent water layer thickness, while transmission and reflection coefficients follow the Fresnel formalism. In this work, we evaluate the model in both field settings, using UAS hyperspectral imagery, and laboratory settings, using hyperspectral spectra obtained with a goniometer. Sediment samples obtained from four different field sites representing disparate environmental settings comprised the laboratory analysis while field validation used hyperspectral UAS imagery and coordinated ground truth obtained on a barrier island shore during field campaigns in 2018 and 2019. Analysis of the most significant wavelengths for retrieval indicate a number of different wavelengths in the short-wave infra-red (SWIR) that provide accurate fits to measured soil moisture content in the laboratory with normalized root mean square error (NRMSE)< 0.145, while independent evaluation from sequestered test data from the hyperspectral UAS imagery obtained during the field campaign obtained an average NRMSE = 0.169 and median NRMSE = 0.152 in a bootstrap analysis.

scholarly journals Diethylstilbestrol Modifies the Structure of Model Membranes and Is Localized Close to the First Carbons of the Fatty Acyl Chains

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 220
Author(s):  
Alessio Ausili ◽  
Inés Rodríguez-González ◽  
Alejandro Torrecillas ◽  
José A. Teruel ◽  
Juan C. Gómez-Fernández
Keyword(s):  
Membrane Surface ◽  
Water Layer ◽  
Fatty Acyl ◽  
31P Nmr Spectroscopy ◽  
Relaxation Rates ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Acyl Chains ◽  
Dynamics Simulations

The synthetic estrogen diethylstilbestrol (DES) is used to treat metastatic carcinomas and prostate cancer. We studied its interaction with membranes and its localization to understand its mechanism of action and side-effects. We used differential scanning calorimetry (DSC) showing that DES fluidized the membrane and has poor solubility in DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) in the fluid state. Using small-angle X-ray diffraction (SAXD), it was observed that DES increased the thickness of the water layer between phospholipid membranes, indicating effects on the membrane surface. DSC, X-ray diffraction, and 31P-NMR spectroscopy were used to study the effect of DES on the Lα-to-HII phase transition, and it was observed that negative curvature of the membrane is promoted by DES, and this effect may be significant to understand its action on membrane enzymes. Using the 1H-NOESY-NMR-MAS technique, cross-relaxation rates for different protons of DES with POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) protons were calculated, suggesting that the most likely location of DES in the membrane is with the main axis parallel to the surface and close to the first carbons of the fatty acyl chains of POPC. Molecular dynamics simulations were in close agreements with the experimental results regarding the location of DES in phospholipids bilayers.

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