Kinetics of colloidal particle deposition in microfluidic systems under temperature gradients: experiment and modelling

Soft Matter ◽  
2020 ◽  
Vol 16 (15) ◽  
pp. 3649-3656
Author(s):  
Zhibin Yan ◽  
Xiaoyang Huang ◽  
Lingling Shui ◽  
Chun Yang
Keyword(s):  
Temperature Gradient ◽  
Particle Transport ◽  
Particle Deposition ◽  
Colloidal Particle ◽  
Temperature Gradients ◽  
Bulk Solution ◽  
Collective Effects ◽  
Solution Temperature ◽  
Kinetics Of ◽  
Particle Attachment

The colloidal particle deposition in microchannels is significantly affected by the collective effects of the temperature gradient and the bulk solution temperature during the two deposition steps: the particle transport and the particle attachment.

Kinetics of Colloidal Particle Deposition on Solid Surfaces

1995 ◽  
Vol 175 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Anatoly A. Bochkarev ◽  
Maxim V. Pukhovoy ◽  
Lyubov N. Kasyanova
Keyword(s):  
Particle Deposition ◽  
Colloidal Particle ◽  
Solid Surfaces ◽  
Kinetics Of

scholarly journals Single entity electrochemistry and the electron transfer kinetics of hydrazine oxidation

Nano Research ◽  
2021 ◽  
Author(s):  
Ruiyang Miao ◽  
Lidong Shao ◽  
Richard G. Compton
Keyword(s):  
Electron Transfer ◽  
Bulk Solution ◽  
Relative Contribution ◽  
Rate Determining Step ◽  
Multistep Process ◽  
Ph Range ◽  
Electro Catalytic Oxidation ◽  
Single Particle Impact ◽  
The Impact ◽  
Kinetics Of

AbstractThe mechanism and kinetics of the electro-catalytic oxidation of hydrazine by graphene oxide platelets randomly decorated with palladium nanoparticles are deduced using single particle impact electrochemical measurements in buffered aqueous solutions across the pH range 2–11. Both hydrazine, N2H4, and protonated hydrazine N2H5+ are shown to be electroactive following Butler-Volmer kinetics, of which the relative contribution is strongly pH-dependent. The negligible interconversion between N2H4 and N2H5+ due to the sufficiently short timescale of the impact voltammetry, allows the analysis of the two electron transfer rates from impact signals thus reflecting the composition of the bulk solution at the pH in question. In this way the rate determining step in the oxidation of each specie is deduced to be a one electron step in which no protons are released and so likely corresponds to the initial formation of a very short-lived radical cation either in solution or adsorbed on the platelet. Overall the work establishes a generic method for the elucidation of the rate determining electron transfer in a multistep process free from any complexity imposed by preceding or following chemical reactions which occur on the timescale of conventional voltammetry.

Kinetics of Particle Deposition in the Radial Impinging-Jet Cell

2001 ◽  
Vol 242 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Zbigniew Adamczyk ◽  
Barbara Siwek ◽  
Piotr Warszyński ◽  
Elizeusz Musiał
Keyword(s):  
Particle Deposition ◽  
Impinging Jet ◽  
Kinetics Of

scholarly journals The principle of minimum entropy production and snow structure

2004 ◽  
Vol 50 (170) ◽  
pp. 342-352 ◽  
Author(s):  
Perry Bartelt ◽  
Othmar Buser
Keyword(s):  
Mass Transfer ◽  
Temperature Gradient ◽  
Entropy Production ◽  
Surface Curvature ◽  
The State ◽  
Temperature Gradients ◽  
Curvature Radius ◽  
Minimum Entropy ◽  
Snow Layer ◽  
Minimum Entropy Production

AbstractAn essential problem in snow science is to predict the changing form of ice grains within a snow layer. Present theories are based on the idea that form changes are driven by mass diffusion induced by temperature gradients within the snow cover. This leads to the well-established theory of isothermal- and temperature-gradient metamorphism. Although diffusion theory treats mass transfer, it does not treat the influence of this mass transfer on the form — the curvature radius of the grains and bonds — directly. Empirical relations, based on observations, are additionally required to predict flat or rounded surfaces. In the following, we postulate that metamorphism, the change of ice surface curvature and size, is a process of thermodynamic optimization in which entropy production is minimized. That is, there exists an optimal surface curvature of the ice grains for a given thermodynamic state at which entropy production is stationary. This state is defined by differences in ice and air temperature and vapor pressure across the interfacial boundary layer. The optimal form corresponds to the state of least wasted work, the state of minimum entropy production. We show that temperature gradients produce a thermal non-equilibrium between the ice and air such that, depending on the temperature, flat surfaces are required to mimimize entropy production. When the temperatures of the ice and air are equal, larger curvature radii are found at low temperatures than at high temperatures. Thus, what is known as isothermal metamorphism corresponds to minimum entropy production at equilibrium temperatures, and so-called temperature-gradient metamorphism corresponds to minimum entropy production at none-quilibrium temperatures. The theory is in good agreement with general observations of crystal form development in dry seasonal alpine snow.

Kinetics of Particle Transport to a Solid Surface from an Impinging Jet under Surface and External Force Fields

1998 ◽  
Vol 208 (1) ◽  
pp. 226-240 ◽  
Author(s):  
Chun Yang ◽  
Tadeusz Dabros ◽  
Dongqing Li ◽  
Jan Czarnecki ◽  
Jacob H. Masliyah
Keyword(s):  
External Force ◽  
Solid Surface ◽  
Particle Transport ◽  
Force Fields ◽  
Impinging Jet ◽  
Kinetics Of

XXV.—The Determination of Temperature Gradients over the Greenland Ice Sheet by Optical Methods

1957 ◽  
Vol 64 (4) ◽  
pp. 381-397
Author(s):  
R. A. Hamilton
Keyword(s):  
Temperature Gradient ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Temperature Gradients ◽  
Lower Atmosphere ◽  
Optical Methods ◽  
Snow Surface ◽  
Vertical Angle ◽  
Gradient Measurements

SynopsisThe temperature gradient in the lower atmosphere can be directly determined by measuring the optical refractive index of the air. This method is suitable for use on the Greenland ice sheet where errors introduced by water vapour are small, and where the strong solar radiation reflected by the snow surface makes it difficult to measure temperature differences over height differences of about I metre.The refraction was measured by observing the apparent vertical angle of each of a set of targets at distances up to 4 km. from a theodolite. The refraction was found to vary linearly with the distance of the target. The true vertical angle to the targets was determined when a second theodolite was available and reciprocal sights could be taken with it from the site of target to the fixed theodolite. The true vertical angle varied with time due to slow descent of the theodolite as the firn slumped; a correction for this was made. The standard error of the temperature gradient measurements was about 1.5 × 10−2 C.° per metre. It is considered that the method could be developed and improved so that over a range of only 100 metres temperature gradients could be measured to an accuracy of about 0·1° C. per metre.

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