Potential-difference surface infrared spectroscopy under forced hydrodynamic flow conditions: control and elimination of adsorbate solution-phase interferences

1991 ◽  
Vol 63 (15) ◽  
pp. 1603-1606 ◽  
Author(s):  
Joseph D. Roth ◽  
Michael J. Weaver
Keyword(s):  
Infrared Spectroscopy ◽  
Hydrodynamic Flow ◽  
Solution Phase ◽  
Potential Difference ◽  
Flow Conditions

Hydrodynamic flow conditions through permeable walls

1992 ◽  
Vol 2 (8) ◽  
pp. 1565-1569
Author(s):  
S. Vollmar ◽  
J. A. M. S. Duarte
Keyword(s):  
Hydrodynamic Flow ◽  
Flow Conditions ◽  
Permeable Walls

Cell Adhesion Under Hydrodynamic Flow Conditions

1995 ◽  
Vol 15 (1) ◽  
Author(s):  
Priya K. Gopalan ◽  
David A. Jones ◽  
Larry V. McIntire ◽  
C. Wayne Smith
Keyword(s):  
Cell Adhesion ◽  
Hydrodynamic Flow ◽  
Flow Conditions

An experimental investigation of microplastic transport in fluvial systems

2020 ◽  
Author(s):  
Jan-Pascal Boos ◽  
Benjamin-Silas Gilfedder ◽  
Hassan Elagami ◽  
Sven Frei
Keyword(s):  
Porous Media ◽  
Channel Flow ◽  
Open Channel ◽  
Treatment Plant ◽  
Open Channel Flow ◽  
Agricultural Runoff ◽  
Hydrodynamic Flow ◽  
Waste Water Treatment Plant ◽  
Flow Conditions ◽  
Fluvial Systems

<p>Although a major part of marine microplastic (MP) pollution originates from rivers and streams, the mechanistic behavior of MP in fluvial systems is only poorly understood. MP enter fluvial systems from e.g. waste water treatment plant (WWTP) effluents, sewer overflows during heavy rain events, agricultural runoff, aerial input/atmospheric fallout, road runoff or via fragmentation of plastic litter. As part of this project we want to investigate the hydrodynamic transport mechanisms that control the behavior and re-distribution of MP in open channel flow and the streambed sediments. Hydrodynamic conditions in open channel flow are represented in an experimental flume environment.  Different porous media materials (e.g. aqua beads, glass beads and sand) are used in the flume experiments to shape typical bed form structures such as riffle-pool sequences, ripples and dunes. The aim of this experimental setup is to create hydrodynamic flow conditions such as hydraulic jumps, low and high flow velocity environments for which the transport and sedimentation behavior of MP can be investigated under realistic conditions. Hydrodynamic flow conditions in the flume are characterized using a Laser-Doppler-Anemometry (LDA) and Particle Image Velocimetry (PIV). Detection and tracking of fluorescent MP-particles in open channel flow and in porous media will be achieved with a fluorescence-camera-system.</p>

In situ Spectroelectrochemical Study of the Anodic Dissolution of Silicon by Potential-Difference and Electromodulated FT-IR Spectroscopy

1997 ◽  
Vol 51 (4) ◽  
pp. 519-525 ◽  
Author(s):  
F. Ozanam ◽  
C. Da Fonseca ◽  
A. Venkateswara Rao ◽  
J.-N. Chazalviel
Keyword(s):  
Infrared Spectroscopy ◽  
Anodic Dissolution ◽  
Potential Difference ◽  
Free Carrier Absorption ◽  
Rate Limiting Step ◽  
Microscopic Models ◽  
Carrier Absorption ◽  
Ft Ir ◽  
Electrochemical Interfaces

The anodic dissolution of p-Si has been investigated by in situ infrared spectroscopy. The combination of potential-difference and electromodulated spectroscopies allows for the acquisition of a rather complete picture of the various regimes of the dissolution. After a review of general principles for studying electrochemical interfaces, a study of the interfacial oxide layer formed in the electropolishing regime is presented. Quantitative analysis shows that the thickness and quality of the oxide (density and defect content) depend upon electrode potential. Free-carrier absorption detected in electromodulated spectra shows that the blocking character of the oxide is correlated with the buildup of a stoichiometric oxide of low defectivity at sufficiently positive potentials. Furthermore, the dynamic response to the modulation reveals that oxides formed at weak positive potentials interact with electrolyte species through electro-induced adsorptions/desorptions on charged SiOH sites. At more positive potentials, charge is transported across the oxide by charged defects which could be associated with tricoordinated, positively charged SiO species. Finally, results obtained during porous silicon formation at weak positive potentials are presented. Potential-difference spectroscopy indicates that the electrode exhibits a very large specific surface area, and that the surface is covered by SiH bonds. Electromodulated infrared spectroscopy reveals that the SiH species are generated upon anodic current flowing and that the breaking of these bonds is the rate-limiting step of the anodic reaction. These unexpected results have given rise to the elaboration of new microscopic models for the direct anodic dissolution of silicon in fluoride electrolytes.

On the maximum width of oil stringers under hydrodynamic flow conditions

1996 ◽  
Vol 28 (3) ◽  
pp. 331-339 ◽  
Author(s):  
R. O. Thomsen ◽  
I. Lerche
Keyword(s):  
Hydrodynamic Flow ◽  
Flow Conditions ◽  
Maximum Width

scholarly journals Flow environment and matrix structure interact to determine spatial competition inPseudomonas aeruginosabiofilms

2016 ◽  
Author(s):  
Carey D. Nadell ◽  
Deirdre Ricaurte ◽  
Jing Yan ◽  
Knut Drescher ◽  
Bonnie L. Bassler
Keyword(s):  
Spatial Competition ◽  
Flow Speed ◽  
Hydrodynamic Flow ◽  
Natural Environments ◽  
Wild Type ◽  
Flow Conditions ◽  
Matrix Organization ◽  
Matrix Production ◽  
Spatial Architecture ◽  
Simple Flow

AbstractBacteria often live in biofilms, which are microbial communities surrounded by a secreted extracellular matrix. Here, we demonstrate that hydrodynamic flow and matrix organization interact to shape competitive dynamics inPseudomonas aeruginosabiofilms. Irrespective of initial frequency, in competition with matrix mutants, wild type cells always increase in relative abundance in straight-tunnel microfluidic devices under simple flow regimes. By contrast, in microenvironments with complex, irregular flow profiles - which are common in natural environments - wild type matrix-producing and isogenic non-producing strains can coexist. This result stems from local obstruction of flow by wild-type matrix producers, which generates regions of near-zero flow speed that allow matrix mutants to locally accumulate. Our findings connect the evolutionary stability of matrix production with the hydrodynamics and spatial structure of the surrounding environment, providing a potential explanation for the variation in biofilm matrix secretion observed among bacteria in natural environments.Impact StatementThe feedback between hydrodynamic flow conditions and biofilm spatial architecture drives competition inP. aeruginosabiofilms, and can explain the variation in biofilm production observed among bacteria in natural environments.

Reversibility of Functional and Structural Changes of Lysozyme Subjected to Hydrodynamic Flow

2012 ◽  
Vol 3 (1) ◽  
Author(s):  
Burcu Kaplan Türköz ◽  
Anastassia Zakhariouta ◽  
Muhsincan Sesen ◽  
Alpay Taralp ◽  
Ali Koşar
Keyword(s):  
Time Course ◽  
Structural Changes ◽  
Initial Study ◽  
Hydrodynamic Flow ◽  
Hydrodynamic Cavitation ◽  
Hydrodynamic Diameter ◽  
Flow Conditions ◽  
Potential Risks ◽  
And Function ◽  
Microchannel Device

In this initial study, the effect of hydrodynamic flow on lysozyme structure and function was investigated using a microchannel device. Protein was subjected to bubbly cavitation as well as noncavitating flow conditions at pH 4.8 and 25 °C. Interestingly, time course analyses indicated that the secondary structure content, the hydrodynamic diameter, and enzymatic activity of lysozyme were unaffected by cavitation. However, noncavitating flow conditions did induce a decrease of the hydrodynamic diameter. The corresponding structural change was subtle to the extent that bioactivity was marginally suppressed. Moreover, native diameter and bioactivity could be fully restored following a brief period of ultrasonication. The findings encouraged further study of various hydrodynamic flow conditions in order to better ascertain the potential risks and benefits of invasive hydrodynamic cavitation in medicine. The results also served to highlight the counter-intuitive notion that proteins need not necessarily be denatured in high-shear media, risks that typically correlate well with forcefully agitated solutions.

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