Coupling fluid water

In order to provide the necessary coupling fluid the grip of the probe holder contains a small tank with a mixture of glycerine and water. Thus the operator is able to provide some drops of the liquid to every blade to be inspected. 

However, oil was wanted for coupling to avoid problems with water deposits left on the tubes after inspection. Therefore, a measuring series was made using different couplings fluids and two different transducers (10 and 20 MHz). 

The above-mentioned consideration indicates that important factors controlling the precipitations of barite and silica are surface area/water mass ratio (A/M), temperature, precipitation rate constant (k) and flow rate (u), and the coupled fluid flow-precipitation models are applicable to understanding the distributions of minerals in submarine hydrothermal ore deposits. 

The coefficients k are given in Table 3.3 with T in °C. The polynomial expansion is useful in analysis programs to calculate the velocity from the temperature. The attenuation in water decreases with temperature, but the rate of decrease is less at higher temperatures. The attenuation and velocity are plotted against temperature in Fig. 3.1. For practical operation of an acoustic microscope with water as the coupling fluid, the smallest lens radius for routine operation is 40 pm (focal length 46pm). With water at 60°C a lens... 

The starting point for the design of lens for surface imaging is the choice of the frequency for which it is to be used. This determines the attenuation per unit distance in the coupling fluid (Table 3.1). In water the attenuation is about... 

In acoustic microscopy, viscous attenuation is most significant in the coupling fluid. In water (and all the other fluids in Table 3.1 except CS2 and superfluid 4He) at the frequencies used in acoustic microscopy, the relaxation time is much less than the period of the wave. Thus cot [Pg.77]

This table gives the accuracy required in each experimental parameter in order to measure a Rayleigh velocity in the vicinity of 3000 m s-1 from V(z) with water as the coupling fluid, assuming the other parameters are exact. If each parameter contributes equal error, then from (8.47) each tolerance must be reduced by 1/ /3. 

The preceding studies were mainly carried out under free field conditions at high frequencies. Weber and Chon [35] carried out similar measurements at low frequency (21.5 kHz) under restricted field conditions. Their experimental device, similar to that used by Timmerhaus and Fogler [36], is illustrated in Figure 13. The emitter is a magnetostrictive transducer with base area 16 cm2 attached by epoxy to the bottom of a 600 cm3 beaker filled with water as coupling fluid. A tube... 

Unsaturated flow formulation is necessary here as far as suction has to be known. The flow model used is based on works in relation with the problem of nuclear waste disposal (Collin et al. 2002a). For each fluid (Water and oil), balance equations and state equations are written. In partial saturation conditions, the permeability and the storage law have to be modified a generalised Darcy s law defines the fluid motion (Bear 1972). Numerous couplings existing between mechanics and flows are considered. 

By placing the reaction vessel in a tank containing a coupling fluid (usually water) which is sonicated either by a metal plate or a horn (indirect sonication) ultrasonic waves travel through this fluid before contacting the reaction vessel... 

For typical fluids (water and most organic solvents), xl (at 10 MHz) is on the order of 170 nm. The effectively coupled mass of this fluid layer, expressed as an areal mass density, is simply the product of Xl and the fluid density. For a smooth 10-MHz resonator, immersion in an aqueous solution couples ca. 17 ngcm of fluid, resulting in a decrease in the resonant frequency of ca. 3.8 kHz. Beyond this relatively small (cf 10 MHz operating frequency) baseline shift , the EQCM can then be used in situ to study interfadal processes under potential control. 

In C-SAM analysis, no special preparations are required. Sealed units can be examined as readily as open units. A coupling fluid is required between the DUT and the transducer. Although the most common fluid used is water, other fluids may be used. 

Silica concentration in deep ground water in the granitic rock area (e.g., Kamaishi, Japan) is in equilibrium with SiOz mineral (chalcedony) (Fig. 1.27). Based on a coupled fluid flow-dissolution-precipitation kinetics model the relationship between residence time of deep ground water and A/M was derived, and the reasonable values of x is estimated to be more than 40 years (Shikazono and Fujimoto 2001). 

Eor very large diameter pipes, the pipe is cooled by water spray and an ultrasonic gauge may be traversing the perimeter. Water is pumped to act as a coupling fluid between the gauge and the pipe wall. 

A modelling approach that could fulfil this need is based on the stationary-state approximation to coupled fluid flow and water-rock interaction (Lichtner 1985, 1988). This model represents the chemical evolution of an open, flow-through system as a sequence of relatively long-lived stationary states of the system, which are linked in time by short-lived transients. The basis for the model is the observation that within a representative elemental volume of a rock-water system, the aqueous concentration of any particular species is generally much less than its concentration in minerals. Long periods of time are therefore necessary to dissolve, or precipitate, minerals such that the spatial distribution of mineral abundances, surface area, porosity and permeability is altered significantly. Each time interval represents a stationary state of the system, in which fluid composition, reaction rates and the distribution of primary and alteration minerals vary only as a function of position in the flow path, not of time. 

Turbulence and high fluid velocities resulting from normal pump operation accelerated metal loss by abrading the soft, graphitically corroded surface (erosion-corrosion). The relatively rapid failure of this impeller is due to the erosive effects of the high-velocity, turbulent water coupled with the aggressiveness of the water. Erosion was aided in this case by solids suspended in the water. 

There is also a general failure to recognize that cooling water quality can be very dynamic. Do not, for example, make the mistake of installing a new tower, placing it into operation, and ignoring the water treatment for a few days. Some closely coupled systems with small water volumes (evaporative condensers and fluid coolers lending the best examples) can be scaled in a matter of hours. 

Supercritical fluid extraction (SFE) and Solid Phase Extraction (SPE) are excellent alternatives to traditional extraction methods, with both being used independently for clean-up and/or analyte concentration prior to chromatographic analysis. While SFE has been demonstrated to be an excellent method for extracting organic compounds from solid matrices such as soil and food (36, 37), SPE has been mainly used for diluted liquid samples such as water, biological fluids and samples obtained after-liquid-liquid extraction on solid matrices (38, 39). The coupling of these two techniques (SPE-SFE) turns out to be an interesting method for the quantitative transfer... 

E. Pocumll, R. M. Marce, F. Bonnll, J. L. Bernal, L. Toribio and M. L. Serna, On-line solid-phase extraction coupled to supercritical fluid chromatography to determine phenol and nitrophenols in water , ]. Chromatogr. 755 67-74 (1996). 

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