Characterization of suspended particles collected in groundwater under natural gradient flow conditions

1992 ◽  
Vol 28 (5) ◽  
pp. 1279-1291 ◽  
Author(s):  
D. Ronen ◽  
M. Magaritz ◽  
U. Weber ◽  
A. J. Amiel ◽  
E. Klein
Keyword(s):  
Gradient Flow ◽  
Suspended Particles ◽  
Natural Gradient ◽  
Flow Conditions

Characterisation of Suspended Particles and Associated Metals in Groundwater under Natural Gradient Flow Conditions*

1993 ◽  
Vol 27 (7-8) ◽  
pp. 179-186 ◽  
Author(s):  
D. Ronen ◽  
M. Magaritz ◽  
A. J. Amiel
Keyword(s):  
Organic Matter ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Gradient Flow ◽  
Suspended Particles ◽  
Average Concentration ◽  
Saturated Zone ◽  
Natural Gradient ◽  
Flow Conditions ◽  
Anoxic Conditions

Microscale Eulerian variations in the flux, mineralogical composition and size of suspended particles have been found in a contaminated sandy aquifer under natural gradient flow conditions () during an 8 month study period. Particle variability has been detected along a 16 m saturated section of the aquifer at a scale of centimeters and meters in the vertical and horizontal dimensions, respectively. The average concentration of particles in groundwater varied between 1 to 70 mg/l. The particles were primarily composed of CaCO3 (11% to 57%), quartz (7% to 39%) and clays (8% to 43%). Most of the particles were within the 140 to 3,000 nm size range with size modes varying from 310 to 660 nm. The large amounts of suspended particles are considered to be related to high inputs of dissolved organic carbon into groundwater from sewage effluents which have been used for agricultural irrigation since the early 1960's. As a result of organic matter biodegradation in the saturated zone, anoxic conditions developed and the pCO2 content of groundwater increased dramatically. It is postulated that part of the carbonate cement of the rocks dissolved and detrital CaCO3, quartz and clay were released as colloidal particles. In the prevailing anoxic conditions of groundwater at the study site (DO < 1 mg/l) colloidal stability is enhanced by organic matter coating of particles. The transport of metals associated with suspended particles in the saturated zone and the interaction of these particles in the aquifer environment have been ascertained through a comparison of the distribution coefficient of 17 elements as a function of depth. *Contribution No. 61, Department of Environmental Sciences and Energy Research, The Weizmann Institute of Science.

New Method for Sampling Groundwater Colloids under Natural Gradient Flow Conditions

1996 ◽  
Vol 30 (10) ◽  
pp. 3094-3101 ◽  
Author(s):  
Noam Weisbrod ◽  
Daniel Ronen ◽  
Ronit Nativ
Keyword(s):  
Gradient Flow ◽  
New Method ◽  
Natural Gradient ◽  
Flow Conditions

scholarly journals ECOSYSTEM BIOMASS AS A KEY PARAMETER DETERMINING ITS COASTAL PROTECTION SERVICE

2020 ◽  
pp. 29
Author(s):  
Maria Maza ◽  
Fernando Lopez-Arias ◽  
Javier L. Lara ◽  
Inigo J. Losada
Keyword(s):  
Leaf Traits ◽  
Biomechanical Properties ◽  
Coastal Protection ◽  
Flow Conditions ◽  
Flow Energy ◽  
Standing Biomass ◽  
Attenuation Relationships ◽  
Number Of Individuals ◽  
Key Parameter

Estimation of the flow energy dissipation induced by an ecosystem that accounts for its characteristics (i.e. biomechanical properties, morphology, density) and the incident hydrodynamic conditions is crucial if ecosystem-based coastal protection measurements want to be implemented. Characterization of a vegetated ecosystem by measuring leaf traits, biomechanical properties of plants and the number of individuals per unit area involves a lot of effort and is case-specific. Standing biomass can be a unique variable defining the flow energy attenuation capacity of the ecosystem. To explore its relation to the induced energy attenuation on the flow, a new set of experiments using real vegetation with contrasting morphology and biomechanical properties, and subjected to different incident flow conditions is presented. The obtained standing biomass-attenuation relationships will help to quantify the expected coastal protection provided by different vegetated ecosystems based on their standing biomass and the flow conditions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/-qaKkBWZApk

Validation of a Fluid-Structure Interaction Model for the Characterization of Transcatheter Mitral Valve Repair Devices

2021 ◽  
Vol 7 (2) ◽  
pp. 605-608
Author(s):  
Robert Ott ◽  
Alper Ö Öner ◽  
Paul Hermann Bellé ◽  
Finja Borowski ◽  
Klaus-Peter Schmitz ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Flow Conditions ◽  
Valve Repair ◽  
Structure Interaction ◽  
Device Implantation ◽  
Transcatheter Mitral Valve Repair ◽  
Vitro Data ◽  
In Vitro Data

Abstract Mitral regurgitation (MR) is the second most frequent indication for heart valve surgery and catheter interventions. According to European and US-American guidelines, transcatheter mitral valve repair in general and transcatheter edge-to-edge repair (TEER) in particular may be considered as a treatment option for selected high-risk patients. However, the biomechanical impact of TEERdevices on the mitral valve (MV) has not yet been fully understood. To address this problem, a 3D-Fluid-Structure Interaction (FSI) framework utilizing non-linear Finite Element Analysis (FEA) for the MV apparatus and Smoothed Particle Hydrodynamics (SPH) for the pulsatile fluid flow was developed and validated against in vitro data. An artificial MV-model (MVM) with a prolapse in the A2-P2 region and a custom-made TEER device implanted in the A2-P2 region were used for the in vitro investigations. In accordance with ISO 5910, projected mitral orifice areas (PMOA), flow rates as well as atrial and ventricular pressures were measured under pulsatile flow conditions before and after TEER device implantation. For the FSI-model, the MVM geometry was reconstructed by means of microcomputed tomography in a quasi-stress-free configuration. Quasi-static tensile test data was utilized for the development of linear- and hyperelastic material models of the chordae tendineae and leaflets, respectively. The fluid flow was modelled assuming an incompressible, homogenous Newtonian behaviour. Time-varying in vitro transmitral pressure loading was applied as a boundary condition. In vitro investigations show that TEER device implantation in the A2-P2 region effectively reduces the regurgitation fraction (RF) from 55 % to 13 %. Moreover, the comparison of experimental and numerical data yields a deviation of 2.09 % for the RF and a deviation of 0.40 % and 6.47 % for the maximum and minimum PMOA, respectively. The developed FSI-framework is in good agreement with in vitro data and is therefore applicable for the characterization of the biomechanical impact of different TEER devices under pulsatile flow conditions.

Characterization of the Sharkskin Defect and its Development with the Flow Conditions**

1989 ◽  
Vol 4 (2) ◽  
pp. 78-84 ◽  
Author(s):  
P. Beaufils ◽  
B. Vergnes ◽  
J. F. Agassant
Keyword(s):  
Flow Conditions

scholarly journals Gas permeability in rarefied flow conditions for characterization of mineral membrane support

2020 ◽  
Vol 79 ◽  
pp. 44-53 ◽  
Author(s):  
C. Savaro ◽  
J.P. Bonnet ◽  
M.V. Johansson ◽  
P. Perrier ◽  
I. Graur ◽  
...  
Keyword(s):  
Gas Permeability ◽  
Flow Conditions ◽  
Rarefied Flow
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