Prediction of solute concentration gradients during growth of discontinuous precipitates in a Fe-13.5 at.% Zn alloy

2021 ◽  
pp. 130317
Author(s):  
Mateusz Chronowski ◽  
Jarosław Opara ◽  
Olga A. Kogtenkova ◽  
Alexander V. Druzhinin ◽  
Paweł Zięba
Keyword(s):  
Solute Concentration ◽  
Concentration Gradients ◽  
Zn Alloy

EFFECTS OF OSMOTIC GRADIENTS ACROSS THE PRIMATE PLACENTAL UPON FETAL AND PLACENTAL WATER CONTENTS

PEDIATRICS ◽  
1964 ◽  
Vol 34 (3) ◽  
pp. 407-411
Author(s):  
Paul D. Bruns ◽  
Andre E. Hellegers ◽  
A. Elmore Seeds ◽  
Richard E. Behrman ◽  
Frederick C. Battaglia
Keyword(s):  
Sodium Chloride ◽  
Amniotic Fluid ◽  
Rhesus Monkeys ◽  
Solute Concentration ◽  
Total Water Content ◽  
Total Water ◽  
Concentration Gradients ◽  
Maternal Circulation ◽  
Total Body ◽  
Water Contents

Infusions of 2.7 g/100 ml sodium chloride or 30 g/100 ml disaccharide solutions into the maternal circulation of pregnant rhesus monkeys produced a significant reduction in fetal and placental total water content. At the same time large transplacental total solute concentration gradients were produced. The injection of sucrose into the amniotic fluid of pregnant rhesus monkeys produced a reduction in fetal total body water alone. The significance of these differences is discussed.

Diffusiophoresis of a charged drop

2018 ◽  
Vol 852 ◽  
pp. 37-59 ◽  
Author(s):  
Fan Yang ◽  
Sangwoo Shin ◽  
Howard A. Stone
Keyword(s):  
Analytical Solution ◽  
Oil Recovery ◽  
Electrolyte Solution ◽  
Solute Concentration ◽  
Solid Particles ◽  
Concentration Gradients ◽  
Charged Drop ◽  
Electric Stress ◽  
Potential Applications ◽  
Soft Objects

Diffusiophoresis describes the motion of colloids in an electrolyte or non-electrolyte solution where there is a concentration gradient. While most of the studies of diffusiophoresis focus on the motion of solid particles, soft objects such as drops and bubbles are also known to experience diffusiophoresis. Here, we investigate the diffusiophoresis of charged drops in an electrolyte solution both analytically and experimentally. The drop is assumed to remain spherical. An analytical solution of the diffusiophoretic velocity of drops is obtained by perturbation methods. We find that the flow inside the drop is driven by the tangential electric stress at the interface and it directly influences the diffusiophoretic speed of the drop. Using charged oil droplets, we measure the drop speed under solute concentration gradients and find good agreement with the analytical solution. Our findings have potential applications for oil recovery and drug delivery.

scholarly journals Micro-analytical studies of discontinuous precipitation in Fe-13.5 at.% Zn alloy

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Paweł Zięba ◽  
Mateusz Chronowski ◽  
Jerzy Morgiel
Keyword(s):  
Volume Diffusion ◽  
Discontinuous Precipitation ◽  
Analytical Electron Microscopy ◽  
Solute Concentration ◽  
Original Form ◽  
Left Behind ◽  
Analytical Electron ◽  
First Time ◽  
Zn Alloy ◽  
Boundary Diffusivity

Abstract For the first time, the analytical electron microscopy has been used to determine the solute concentration profiles left behind the moving reaction front (RF) of the discontinuous precipitation (DP) reaction in a Fe-13.5 at.% Zn alloy. These profiles have been converted into grain boundary diffusivity (sδDb) values, using Cahn’s diffusion equation in its original form and the data of the growth rate of the discontinuous precipitates obtained from independent measurements. This approach has essentially removed existing difference in comparison to sδDb values obtained from Cahn′s simplified and Petermann–Hornbogen models relevant for the global approach to the DP. Simultaneously, the local values of sδDb have been up to 8–10 orders of magnitude higher than the data for volume diffusion coefficients and much greater than for diffusion at the stationary grain boundaries of Zn in pure Fe. This is clear indication that the rate controlling factor for DP reaction in the Fe-13 at.% Zn alloy is diffusion at the moving RF.

Effect of Solute Concentration Gradients on the Onset of Convection: Uniform and Nonuniform Initial Gradients

1986 ◽  
Vol 108 (4) ◽  
pp. 776-782 ◽  
Author(s):  
M. Kaviany ◽  
M. Vogel
Keyword(s):  
Temperature Gradient ◽  
Concentration Gradient ◽  
Fluid Layer ◽  
Onset Time ◽  
Solute Concentration ◽  
Concentration Gradients ◽  
Linear Amplification ◽  
Onset Of Convection ◽  
Gradient Layer ◽  
Good Agreement

The time of the onset of convection in a fluid layer, which is initially stably stratified and then heated from below in a transient manner, is determined experimentally and analytically. The initial stratification is due to the presence of a solute concentration gradient. In addition to initial linear solute concentration distributions two other specific initial solute concentration distributions are considered. In Case 1, a zero gradient layer is located underneath a nonzero and uniform gradient layer. In Case 2, the zero gradient layer is on the top. The linear amplification theory is applied to the prediction of the onset time. Interferometry is used as a means of determining the onset time experimentally. It is shown that since the adverse temperature gradient is concentrated near the bottom, any nonuniformity in the solute concentration gradient in this region reduces the effectiveness of the gradient in delaying the onset. Experimental and predicted results are in good agreement.

Electrospray Ionization of Polymers: Evaporation, Drop Fission, and Deposited Particle Morphology

2014 ◽  
Author(s):  
Marriner H. Merrill ◽  
William R. Pogue ◽  
Jared N. Baucom
Keyword(s):  
Electrospray Ionization ◽  
Polymer Concentration ◽  
Particle Morphology ◽  
Solute Concentration ◽  
Spray Parameters ◽  
Size Distributions ◽  
Concentration Gradients ◽  
Surface Areas ◽  
Particle Size And Morphology ◽  
Size And Morphology

The fundamental challenge of nanomanufacturing is to create, control, and assemble enormous quantities of nanoscale objects and distribute them over large surface areas. Electrospray ionization (ESI) has the potential to address this challenge due to its simplicity, applicability to a broad range of materials, and intrinsic scalability. ESI uses high voltages to electrically charge and disperse materials ranging in size from sub-nanometers to micrometers in diameter, which can then be guided and deposited on a substrate. However, the interactions between initial spray parameters and final deposited morphology are not well understood. In this study, we show that when electrospraying polymers, deposited particle size and morphology can be modified through the initial polymer concentration and nozzle-substrate distance. We report the results of electrospraying 0.1% and 0.5% concentrations of poly(acrylic acid) (PAA) onto substrates with 1, 3, and 5 cm nozzle-substrate distances. Scanning electron microscopy showed that deposited particles ranged from less than 10 nm to nearly 200 nm in diameter with tight, multi-modal size distributions. Particle shape and spread on the substrate were also examined. We use physics-based models to show that the size distributions are a function of the evaporation and drop fission during the spray along with the effect of solute concentration gradients within an evaporating drop. This work validates our previously developed models and will lead to future process guidelines.

Electrospray Ionization of Polymers: Evaporation, Drop Fission, and Deposited Particle Morphology1

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Marriner H. Merrill ◽  
William R. Pogue ◽  
Jared N. Baucom
Keyword(s):  
Particle Size ◽  
Electrospray Ionization ◽  
Solute Concentration ◽  
Experimental Results ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Concentration Gradients ◽  
Surface Areas ◽  
Fundamental Challenge ◽  
Coulomb Fission

The fundamental challenge of nanomanufacturing is to create, control, and place immense quantities of nanoscale objects controllably over large surface areas. Electrospray ionization (ESI) has the potential to address this challenge due to its simplicity, applicability to a broad range of materials, and intrinsic scalability. However, the interactions between electrospray parameters and final deposited morphology are not well understood. Experimental results are combined with physics-based models to explain how observed particle size distributions are caused in the spray by evaporation and Coulomb fission of drops with solute concentration gradients.

scholarly journals Coastal dynamics and submarine permafrost in shallow water of the central Laptev Sea, East Siberia

2016 ◽  
Vol 10 (4) ◽  
pp. 1449-1462 ◽  
Author(s):  
Pier Paul Overduin ◽  
Sebastian Wetterich ◽  
Frank Günther ◽  
Mikhail N. Grigoriev ◽  
Guido Grosse ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Solute Concentration ◽  
The Arctic ◽  
Laptev Sea ◽  
Permafrost Degradation ◽  
East Siberia ◽  
Concentration Gradients ◽  
Study Region ◽  
Degradation Rates ◽  
A Site

Abstract. Coastal erosion and flooding transform terrestrial landscapes into marine environments. In the Arctic, these processes inundate terrestrial permafrost with seawater and create submarine permafrost. Permafrost begins to warm under marine conditions, which can destabilize the sea floor and may release greenhouse gases. We report on the transition of terrestrial to submarine permafrost at a site where the timing of inundation can be inferred from the rate of coastline retreat. On Muostakh Island in the central Laptev Sea, East Siberia, changes in annual coastline position have been measured for decades and vary highly spatially. We hypothesize that these rates are inversely related to the inclination of the upper surface of submarine ice-bonded permafrost (IBP) based on the consequent duration of inundation with increasing distance from the shoreline. We compared rapidly eroding and stable coastal sections of Muostakh Island and find permafrost-table inclinations, determined using direct current resistivity, of 1 and 5 %, respectively. Determinations of submarine IBP depth from a drilling transect in the early 1980s were compared to resistivity profiles from 2011. Based on borehole observations, the thickness of unfrozen sediment overlying the IBP increased from 0 to 14 m below sea level with increasing distance from the shoreline. The geoelectrical profiles showed thickening of the unfrozen sediment overlying ice-bonded permafrost over the 28 years since drilling took place. We use geoelectrical estimates of IBP depth to estimate permafrost degradation rates since inundation. Degradation rates decreased from over 0.4 m a−1 following inundation to around 0.1 m a−1 at the latest after 60 to 110 years and remained constant at this level as the duration of inundation increased to 250 years. We suggest that long-term rates are lower than these values, as the depth to the IBP increases and thermal and porewater solute concentration gradients over depth decrease. For the study region, recent increases in coastal erosion rate and changes in benthic temperature and salinity regimes are expected to affect the depth to submarine permafrost, leading to coastal regions with shallower IBP.

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