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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Diffusion coefficients of quinine in supercritical CO2

Gaponenko, Y., Mialdun, A., Shevtsova, V. 06 February 2020 (has links)
Single-particle tracking experiments have measured the distribution of dwell times of various DNAbinding species — including CRISPR-Cas9, TetR, and LacI — diffusing in living cells. The observed truncated power law distribution has direct and indirect implications. One direct implication is that the observed dwell time distribution is inconsistent with the Gaussian distribution of binding energies generally obtained from bioinformatics. Consideration of length scales of the nucleus and the measurement is essential to understanding the dwell time distribution.
2

Matrix Fracture Interaction In Sandstone Rocks During Carbon Dioxide, Methane And Nitrogen Injection

Bulbul, Sevtac 01 June 2012 (has links) (PDF)
The aim of the study is to investigate matrix-fracture interaction, gas oil gravity drainage (GOGD) and diffusion mechanisms with CO2, N2 and CH4 gas injection in a fractured system. Effects of injected gas type, initial gas saturation and diffusion coefficient on oil recovery are studied by an experimental and simulation work. In the experimental study, Berea sandstone cores are placed in a core holder and the space created around the core is considered as a surrounding fracture. System is kept at a pressure of 250 psi by CO2, N2 and CH4 gases and at a reservoir temperature of 70 &deg / C. Experiments with cores having similar initial saturations resulted in the highest ndecane recovery in CO2 experiment followed by CH4 and N2. The highest solubility of CO2 in n-decane and density difference between CO2 and CO2-ndecane mixture are considered as the reason of results. CO2 injection tests with n-decane and brine saturated core with and without initial gas saturation indicate that availability of initial gas saturation in matrix increased recovery. A simulation study is continued using CMG (Computer Modeling Group Ltd.) WinProp (Microsoft Windows&trade / based Phase-Behavior and Fluid Property Program) and GEM (Generalized Equation-of-State Model Compositional Reservoir Simulator). Simulation results of CO2 experiment with initial gas show that dominant effect of GOGD decreases and diffusion becomes more effective at final production stages. Simulation study indicates an immediate, sharp decrease in oil saturation in matrix. Oil in matrix migrates into fractures and moves downward as a result of GOGD with gas injection.
3

Metoda termální desorpční spektroskopie (TDS) a její aplikace pro výzkum povrchových procesů / Thermal Desorption Spectroscopy (TDS) and its Application for Research of Surface Processes

Potoček, Michal January 2011 (has links)
ermal desorption spectroscopy (TDS) is a common method for surface analysis of adsorbed molecules. In chapter 1 the work deals with the theoretical background of this method and shows the principles of a desorption process influenced by subsurface diffusion. Chapter 2 first shows application of TDS for detection of surface molecules and determination of binding energy.Experiments were mainly focused on ditermination of surface adsorbents and impurities on Si wafers. The second part of chapter 2 describes desorption of atoms of a Ga layer on Si surface and their subsurface diffusion. A Ga diffusion process was also observed by with secondary ion mass spectrometry (SIMS) and numerically simulated.

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