Does Exceptional Viscous Drag Impede Flow Through a Nano-Sieve's Pores?

MRS Proceedings ◽

10.1557/proc-0930-jj04-06 ◽

2006 ◽

Vol 930 ◽

Author(s):

Peter J. Feibelman ◽

J. E. Houston

Keyword(s):

Bulk Water ◽

Viscous Drag ◽

Dissipative Forces ◽

Functionalized Surfaces ◽

Dissolved Ions ◽

Flow Through ◽

Interfacial Force

ABSTRACTTo address the concern that a material functionalized to reject dissolved ions may give rise to a highly viscous aqueous interphase within nanometers of its surface, we conducted and interpreted Interfacial Force Microscope measurements of the dissipative forces that resist motion of a tip parallel to a sample, in water. The results are consistent with earlier measurements where the tip approached the sample. They confirm that near hydrophilically functionalized surfaces, interphase viscosities more than a million times that of bulk water can be expected.

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SPECTRAL NUMERICAL STUDY OF ENTROPY GENERATION IN MAGNETO-CONVECTIVE VISCOELASTIC BIOFLUID FLOW THROUGH PORO-ELASTIC MEDIA WITH THERMAL RADIATION AND BUOYANCY EFFECTS

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4050935 ◽

2021 ◽

pp. 1-36

Author(s):

Bandaru Mallikarjuna ◽

Srinivas Jangili ◽

G. Gopi Krishna ◽

O. A. Beg ◽

Ali Kadir

Keyword(s):

Magnetic Field ◽

Thermal Radiation ◽

Entropy Generation ◽

Numerical Study ◽

Physical Models ◽

Viscous Drag ◽

Radiation Parameter ◽

Viscoelastic Parameter ◽

Thermal Buoyancy ◽

Flow Through

Abstract Electromagnetic high-temperature therapy is popular in medical engineering treatments for various diseases include tissue damage ablation repair, hyperthermia and oncological illness diagnosis. The simulation of transport phenomena in such applications requires multi-physical models featuring magnetohydrodynamics, biorheology, heat transfer and deformable porous media. Motivated by investigating the fluid dynamics and thermodynamic optimization of such processes, in the present article a mathematical model is developed to study the combined influence of thermal buoyancy, magnetic field and thermal radiation on the fluid and heat characteristics in electrically-conducting viscoelastic biofluid flow through a vertical deformable porous medium. Jefferys elastic-viscous model is deployed to simulate non-Newtonian characteristics of the biofluid. It is assumed that heat is generated within the fluid by both viscous and Darcy (porous matrix) dissipations. The boundary value problem is normalized with appropriate transformations. The non-dimensional biofluid velocity, solid displacement and temperature equations with appropriate boundary conditions are solved computationally using a spectral method. Verification of accuracy is conducted via monitoring residuals of the solutions and Validated with shooting technique is included. The effects of Jeffrey viscoelastic parameter, viscous drag parameter, magnetic field parameter, radiation parameter and buoyancy parameter on flow velocity, solid displacement, temperature and entropy generation are depicted graphically and interpreted at length. Increasing magnetic field and drag parameters are found to reduce the field velocity, solid displacement, temperature and entropy production. Higher magnitudes of thermal radiation parameter retard the flow and decrease Nusselt number whereas they elevate solid displacement.

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Bubble Formation Due to a Submerged Capillary Tube in Quiescent and Coflowing Streams

Journal of Basic Engineering ◽

10.1115/1.3425114 ◽

1970 ◽

Vol 92 (4) ◽

pp. 705-711 ◽

Cited By ~ 44

Author(s):

S. C. Chuang ◽

V. W. Goldschmidt

Keyword(s):

Gas Flow ◽

Capillary Tube ◽

Bubble Formation ◽

Viscous Drag ◽

Proposed Model ◽

Mass Coefficient ◽

Small Tube ◽

Flow Through ◽

Added Mass Coefficient ◽

Good Agreement

The case of bubble formation in both quiescent and moving streams due to the injection of a constant gas flow through a small tube is considered. Relationships predicting the expected size and quantity of bubbles generated are proposed. These are compared with measurements taken with stream velocities up to 9 ft/sec, while generating gas bubbles from 40 to 700 microns in diameter. For the case of generation in a quiescent stream the forces due to the virtual mass, surface tension, viscous drag, buoyancy, and the wake formed by the preceding bubble are accounted for. There still remains some question (only partly answered by a comparison with measurements) as to the proper added mass coefficient and the geometry of the bubble previous to detachment, as well as an adequate estimate of the interaction with a preceding bubble’s wake. The proposed model for generation in a moving stream is in good agreement with actual measurements for co-flowing velocities between 1 and 9 fps and capillary tubes in the order of 10−3 cm in dia.

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Continuous Measurement of the Dissolution Rate of Ions from Glasses

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.39-40.341 ◽

2008 ◽

Vol 39-40 ◽

pp. 341-346 ◽

Cited By ~ 8

Author(s):

Susanne Taipale ◽

Paul Ek ◽

Mikko Hupa ◽

Leena Hupa

Keyword(s):

Inductively Coupled Plasma ◽

Early Stage ◽

Optical Emission ◽

Emission Spectrometry ◽

Ion Release ◽

Durability Test ◽

Aqueous Environments ◽

Dissolved Ions ◽

On Line ◽

Flow Through

A method for measuring the early stage ion release of glasses was developed in order to gain information on leaching kinetics and chemical resistance of glasses in aqueous environments. A continuous flow-through-reactor was designed in which the aqueous solution is fed through a bed of glass particles and the dissolved ions continuously recorded with a sensitive on-line analysis system. Experimental parameters, such as solvent flow rate and temperature, could easily be adjusted according to the needs. The flow-through-reactor system was tested with powdered samples of float and lead glasses, E-glass and bioactive glasses 45S5 and 1-98, all of which showed very different chemical durability in aqueous environments. The reactor was connected to inductively coupled plasma optical emission spectrometry (ICP-OES) and concentrations of the dissolved ions were measured simultaneously on-line every 30-40 seconds. In this work the initial stages of ion release were measured during the first 15 minutes of the leaching experiments at 40°C and 80°C. The results were compared with standard water durability test of the glasses. The dissolution of the glasses according to both methods showed similar behaviour.

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Development of apical pits in chloride cells of the gills of Pimephales promelas after chronic exposure to acid water

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076044 ◽

1983 ◽

Vol 41 ◽

pp. 462-463

Author(s):

Richard L. Leino ◽

Jon G. Anderson ◽

J. Howard McCormick

Keyword(s):

Confidence Interval ◽

Chronic Exposure ◽

Lake Superior ◽

Pimephales Promelas ◽

Chloride Cells ◽

Fathead Minnows ◽

Secondary Lamellae ◽

Untreated Water ◽

Water Ph ◽

Flow Through

Groups of 12 fathead minnows were exposed for 129 days to Lake Superior water acidified (pH 5.0, 5.5, 6.0 or 6.5) with reagent grade H2SO4 by means of a multichannel toxicant system for flow-through bioassays. Untreated water (pH 7.5) had the following properties: hardness 45.3 ± 0.3 (95% confidence interval) mg/1 as CaCO3; alkalinity 42.6 ± 0.2 mg/1; Cl- 0.03 meq/1; Na+ 0.05 meq/1; K+ 0.01 meq/1; Ca2+ 0.68 meq/1; Mg2+ 0.26 meq/1; dissolved O2 5.8 ± 0.3 mg/1; free CO2 3.2 ± 0.4 mg/1; T= 24.3 ± 0.1°C. The 1st, 2nd and 3rd gills were subsequently processed for LM (methacrylate), TEM and SEM respectively.Three changes involving chloride cells were correlated with increasing acidity: 1) the appearance of apical pits (figs. 2,5 as compared to figs. 1, 3,4) in chloride cells (about 22% of the chloride cells had pits at pH 5.0); 2) increases in their numbers and 3) increases in the % of these cells in the epithelium of the secondary lamellae.

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The effects of strain and strain rate on residual microstructures in copper

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143687 ◽

1986 ◽

Vol 44 ◽

pp. 420-421

Author(s):

M. F. Stevens ◽

P. S. Follansbee

Keyword(s):

Strain Rate ◽

Applied Stress ◽

Threshold Stress ◽

Rate Sensitivity ◽

Viscous Drag ◽

Strain Rates ◽

Strain And Strain Rate ◽

Threshold Strength ◽

Mechanism Transition ◽

Intrinsic Strength

The strain rate sensitivity of a variety of materials is known to increase rapidly at strain rates exceeding ∼103 sec-1. This transition has most often in the past been attributed to a transition from thermally activated guide to viscous drag control. An important condition for imposition of dislocation drag effects is that the applied stress, σ, must be on the order of or greater than the threshold stress, which is the flow stress at OK. From Fig. 1, it can be seen for OFE Cu that the ratio of the applied stress to threshold stress remains constant even at strain rates as high as 104 sec-1 suggesting that there is not a mechanism transition but that the intrinsic strength is increasing, since the threshold strength is a mechanical measure of intrinsic strength. These measurements were made at constant strain levels of 0.2, wnich is not a guarantee of constant microstructure. The increase in threshold stress at higher strain rates is a strong indication that the microstructural evolution is a function of strain rate and that the dependence becomes stronger at high strain rates.

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The promises and perfidy of cryomicroscopy and analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010016964x ◽

1994 ◽

Vol 52 ◽

pp. 382-383

Author(s):

Patrick Echlin

Keyword(s):

Low Temperature ◽

High Energy ◽

Short Paper ◽

List Type ◽

Time Resolved ◽

Energy Beam ◽

Cellular Analysis ◽

Dissolved Ions ◽

Embedding Medium ◽

Low Temperature Microscopy

The unusual title of this short paper and its accompanying tutorial is deliberate, because the intent is to investigate the effectiveness of low temperature microscopy and analysis as one of the more significant elements of the less interventionist procedures we can use to prepare, examine and analyse hydrated and organic materials in high energy beam instruments. The promises offered by all these procedures are well rehearsed and the litany of petitions and responses may be enunciated in the following mantra.Vitrified water can form the perfect embedding medium for bio-organic samples.Frozen samples provide an important, but not exclusive, milieu for the in situ sub-cellular analysis of the dissolved ions and electrolytes whose activities are central to living processes.The rapid conversion of liquids to solids provides a means of arresting dynamic processes and permits resolution of the time resolved interactions between water and suspended and dissolved materials.The low temperature environment necessary for cryomicroscopy and analysis, diminish, but alas do not prevent, the deleterious side effects of ionizing radiation.Sample contamination is virtually eliminated.

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STEM measurement of subcellular water distributions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100148678 ◽

1993 ◽

Vol 51 ◽

pp. 568-569

Author(s):

R.D. Leapman ◽

S.Q. Sun ◽

S-L. Shi ◽

R.A. Buchanan ◽

S.B. Andrews

Keyword(s):

Water Content ◽

Internal Standard ◽

Dry Weight ◽

Dry Mass ◽

Scanning Transmission Electron Microscope ◽

Dark Field ◽

Bulk Water ◽

Inelastic Electron ◽

Scanning Transmission ◽

Annular Dark Field

Recent advances in rapid-freezing and cryosectioning techniques coupled with use of the quantitative signals available in the scanning transmission electron microscope (STEM) can provide us with new methods for determining the water distributions of subcellular compartments. The water content is an important physiological quantity that reflects how fluid and electrolytes are regulated in the cell; it is also required to convert dry weight concentrations of ions obtained from x-ray microanalysis into the more relevant molar ionic concentrations. Here we compare the information about water concentrations from both elastic (annular dark-field) and inelastic (electron energy loss) scattering measurements.In order to utilize the elastic signal it is first necessary to increase contrast by removing the water from the cryosection. After dehydration the tissue can be digitally imaged under low-dose conditions, in the same way that STEM mass mapping of macromolecules is performed. The resulting pixel intensities are then converted into dry mass fractions by using an internal standard, e.g., the mean intensity of the whole image may be taken as representative of the bulk water content of the tissue.

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