Mass Transfer in Binary Systems without Bulk Flow: Steady-State Examples

2019 ◽  
pp. 109-160
Author(s):  
İsmail Tosun
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Binary Systems ◽  
Bulk Flow

Exchange of inulin and dextran between blood and cerebrospinal fluid

1961 ◽  
Vol 201 (6) ◽  
pp. 1145-1148 ◽  
Author(s):  
Arthur R. Rothman ◽  
Emil J. Freireich ◽  
James R. Gaskins ◽  
Clifford S. Patlak ◽  
David P. Rall
Keyword(s):  
Cerebrospinal Fluid ◽  
Steady State ◽  
Venous System ◽  
Bulk Flow ◽  
Entry Rate ◽  
Important Means ◽  
Subarachnoid Spaces

C14-labeled inulin (mol. wt. 5,000) and C14-labeled dextran (mol. wt. 12,800 and 77,700) were studied for entry rate into CSF and steady state ratio of drug in cerebrospinal fluid (CSF) to drug in plasma, in nephrectomized dogs. For all three of these compounds the entry rates and steady state ratios were very similar. Exit rates of C14-inulin and C14-dextran (mol. wt. 77,700) were studied in nephrectomized and nonnephrectomized dogs. The exit rates were rapid and very similar for the two compounds. Acetazolamide increased the steady state ratio and decreased the exit rates significantly. These data suggest the presence of leaks in the blood CSF barrier of at least 60 A in diameter and indicate that bulk flow of CSF from the subarachnoid spaces to the venous system is an important means of exit of substances present in the CSF. Compounds which enter the CSF slowly fail to achieve diffusion equilibrium because of their relatively rapid exit by means of bulk flow.

scholarly journals A frequency quantum interpretation of the surface renewal model of mass transfer

2017 ◽  
Vol 4 (7) ◽  
pp. 170103 ◽  
Author(s):  
Chanchal Mondal ◽  
Siddharth G. Chatterjee
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Frequency Distribution ◽  
Age Distribution ◽  
Gas Absorption ◽  
Bulk Liquid ◽  
Gas Transfer ◽  
Transfer Resistance ◽  
Surface Renewal ◽  
Two Parameter

The surface of a turbulent liquid is visualized as consisting of a large number of chaotic eddies or liquid elements. Assuming that surface elements of a particular age have renewal frequencies that are integral multiples of a fundamental frequency quantum, and further assuming that the renewal frequency distribution is of the Boltzmann type, performing a population balance for these elements leads to the Danckwerts surface age distribution. The basic quantum is what has been traditionally called the rate of surface renewal. The Higbie surface age distribution follows if the renewal frequency distribution of such elements is assumed to be continuous. Four age distributions, which reflect different start-up conditions of the absorption process, are then used to analyse transient physical gas absorption into a large volume of liquid, assuming negligible gas-side mass-transfer resistance. The first two are different versions of the Danckwerts model, the third one is based on the uniform and Higbie distributions, while the fourth one is a mixed distribution. For the four cases, theoretical expressions are derived for the rates of gas absorption and dissolved-gas transfer to the bulk liquid. Under transient conditions, these two rates are not equal and have an inverse relationship. However, with the progress of absorption towards steady state, they approach one another. Assuming steady-state conditions, the conventional one-parameter Danckwerts age distribution is generalized to a two-parameter age distribution. Like the two-parameter logarithmic normal distribution, this distribution can also capture the bell-shaped nature of the distribution of the ages of surface elements observed experimentally in air–sea gas and heat exchange. Estimates of the liquid-side mass-transfer coefficient made using these two distributions for the absorption of hydrogen and oxygen in water are very close to one another and are comparable to experimental values reported in the literature.

scholarly journals Mass Transfer in Binary Systems: A Numerical Approach

2007 ◽  
Vol 3 (S246) ◽  
pp. 271-272
Author(s):  
C.-P. Lajoie ◽  
A. Sills
Keyword(s):  
Mass Transfer ◽  
Smoothed Particle Hydrodynamics ◽  
Binary Systems ◽  
Numerical Approach ◽  
Central Point ◽  
Point Mass ◽  
Blue Straggler ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Transfer Flow

AbstractWe present preliminary work on the formation scenario of blue straggler stars by mass transfer in binary systems. More precisely, using Smoothed Particle Hydrodynamics (SPH), we want to model only the outer parts of the stars in order to get a much greater spatial resolution of the mass transfer flow itself. The inner boundary conditions are achieved using the so-called ghost particles and by replacing the inner mass by a central point mass. Stability of this central point mass is crucial, and it is shown that we get reasonable results. These simulations should give us indications on which layers of the donor star are actually transferred to the other star as well as how mass is transferred and how it settles on the accretor. This work is aimed at getting distinct observational signatures which would help identifying the dominant formation mechanism of blue straggler stars.

Constraining Progenitors of Observed Low-mass X-ray Binaries Using Convection and Rotation-Boosted Magnetic Braking

2021 ◽  
Vol 922 (2) ◽  
pp. 174
Author(s):  
Kenny X. Van ◽  
Natalia Ivanova
Keyword(s):  
Mass Transfer ◽  
Binary Systems ◽  
Formation Rate ◽  
Mass Transfer Rate ◽  
Population Synthesis ◽  
X Ray ◽  
Synthesis Technique ◽  
Low Mass ◽  
Magnetic Braking ◽  
X Ray Binaries

Abstract We present a new method for constraining the mass transfer evolution of low-mass X-ray binaries (LMXBs)—a reverse population synthesis technique. This is done using the detailed 1D stellar evolution code MESA (Modules for Experiments in Stellar Astrophysics) to evolve a high-resolution grid of binary systems spanning a comprehensive range of initial donor masses and orbital periods. We use the recently developed convection and rotation-boosted (CARB) magnetic braking scheme. The CARB magnetic braking scheme is the only magnetic braking prescription capable of reproducing an entire sample of well-studied persistent LMXBs—those with mass ratios, periods, and mass transfer rates that have been observationally determined. Using the reverse population synthesis technique, where we follow any simulated system that successfully reproduces an observed LMXB backward, we have constrained possible progenitors for each observed well-studied persistent LMXB. We also determined that the minimum number of LMXB formations in the Milky Way is 1500 per Gyr if we exclude Cyg X-2. For Cyg X-2, the most likely formation rate is 9000 LMXB Gyr−1. The technique we describe can be applied to any observed LMXB with well-constrained mass ratio, period, and mass transfer rate. With the upcoming GAIA DR3 containing information on binary systems, this technique can be applied to the data release to search for progenitors of observed persistent LMXBs.

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