Methods immersion

Consider a sample with orthorhombic symmetry which is cut such that the width, thickness and length directions coincide with the symmetry axes 1, 2 and 3, respectively. When the sample is aligned 

The velocity and the angles of refraction 0 can be deduced from transit time measurements and Snell s law. The transit time is measured with and without the sample in the path of the ultrasonic beam, and the difference in these transit times is 

In principle, only four velocity measurements are required to obtain the four stiffness constants. However, to achieve higher accuracy we adopt the following procedure. First, the sample is set at ij/ = 0. Only the longitudinal wave is generated in the sample and its velocity Is related to by 

Once has been measured, the variables x and y can be computed from the measured and 6 at different angles of incidence according to equations (14.8) and (14.9). Then (n = 1-3) and hence the stiffnesses C33 and can be determined by a least squares fit of equation (14.7) to these data. At least ten data points for each of 

Similar measurements for wave propagating in the 1—2 plane and 1-3 plane give the two sets of stiffness constants, (C, and (Cjj, C33, Cj3, C ), respectively. Therefore, the three series of velocity measurements give the nine independent stiffness constants, C C 

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The general type of approach, that is, the comparison of an experimental heat of immersion with the expected value per square centimeter, has been discussed and implemented by numerous authors [21,22]. It is possible, for example, to estimate sv - sl from adsorption data or from the so-called isosteric heat of adsorption (see Section XVII-12B). In many cases where approximate relative areas only are desired, as with coals or other natural products, the heat of immersion method has much to recommend it. In the case of microporous adsorbents surface areas from heats of immersion can be larger than those from adsorption studies [23], but the former are the more correct [24]. 

The differential capacitance method cannot be used for reactive metals, such as transition metals in aqueous solutions, on which the formation of a surface oxide occurs over a wide potential re ion. An immersion method was thus developed by Jakuszewski et al. 3 With this technique the current transient during the first contact of a freshly prepared electrode surface with the electrolyte is measured for various immersion potentials. The electrode surface must be absolutely clean and discharged prior to immersion.182-18 A modification of this method has been described by Sokolowski et al. The values of obtained by this method have been found to be in reasonable agreement with those obtained by other methods, although for reactive metals this may not be a sufficient condition for reliability. 

A modified immersion method has been used by Hamm et al.140 to obtain electrochemical cell by a closed-transfer system, and immersed in 0.1 M HCIO4 solution at various . was derived from the charge flowing during the contact with the electrolyte under potential control. For the reconstructed Au(l 11M22 X Vayo.l M HCIO4interface, =0.31 0.04V (SCE) (Table 9). Using the impedance method, = 0.34 V (SCE) for recon-... 

The value obtained by Hamm et alm directly by the immersion method is strikingly different and much more positive than others reported. It is in the right direction with respect to a polycrystalline surface, even though it is an extrapolated value that does not correspond to an existing surface state. In other words, the pzc corresponds to the state of a bare surface in the double-layer region, whereas in reality at that potential the actual surface is oxidized. Thus, such a pzc realizes to some extent the concept of ideal reference state, as in the case of ions in infinitely dilute solution. 

Kauffman, A. M., A Simple Immersion Method to Determine the Refractive Index of Thin Silica Films, Thin Solid Films, Vol. l,No. 1,1967,pp. 131-136. 

Immersion method—In this method, the analyte contained in the tissue may pass into the matrix solution, and information regarding the analyte s localization in the complex tissue structure may deteriorate due to the migration of the analyte, which in turn is caused by the excess matrix solution on the surface of a section. For these reasons, the immersion method is rarely used today. 

The simplest measurement of the response time of macroelectrodes involves the determination of the time elapsed from the transfer of the ISE from the solution in which it was stored into the test solution. Data obtained in this way are only significant for response times of at least tens of seconds. For short response times, flow-through [44, 131] or injection [92] methods are suitable. For microelectrodes, a rapid immersion method [181], a flow-through [166] or an iontophoretic method [97] have given good results. In the last method... 

Morgenthaler SM, Lee S, Spencer ND (2006) Submicrometer structure of surface-chemical gradients prepared by a two-step immersion method. Langmuir 22 2706-2711... 

Tuchin, V. V. 2005. Optical clearing of tissues and blood using the immersion method. J. Phys. D 38 2497-2518. 

Homopolymer was formed by both methods of grafting however, the amount was considerably greater with the immersion method. When the time of grafting in solution was increased beyond 30 minutes, the extent of grafting continued to increase, but there was a tendency for the homopolymer to crosslink and become embedded in the foam. When this occurred, beads of crosslinked homopolymer were trapped in the cells of the foam, and they could not be removed by subsequent washing. 

The PEO salt complexes are generally prepared by direct interaction in solution for soluble systems or by immersion method, soaking the network cross-linked PEO in the appropriate salt solution [52-57]. Besides PEO, poly(propylene)oxide, poly(ethylene)suceinate, poly(epichlorohydrin), and polyethylene imine) have also been explored as base polymers for solid electrolytes [58]. Polyethylene imine) (PEI) is prepared by the ring-opening polymerization of 2-methyloxazoline. Solid solutions of PEI and Nal are obtained by dissolving both in acetonitrile (80 °C) followed by cooling to room temperature and solvent evaporation in vacuo. Polyethyleneimine-NaCF3S03 complexes have also been explored [59],... 

In this chapter the sequence of observations followed in the microscopic method of identification is outlined. The immersion method for the identification of small separate crystals forms the main subject of this chapter, though some remarks on methods for large aggregates will be found at the end. When the immersion method is to be used aggregates may be crushed or ground carefully. 

The thin-section methods of the petrologist may be used for artificial specimens which are in the form of large aggregates—specimens of such materials as refractories, bricks, and boiler scales. Instead of powdering them and using immersion methods, it is possible to grind thin sections and examine them. When it is simply a question of distinguishing between a few possible constituents of known characteristics, this is a useful method. But in unfamiliar systems the powder method is likely to be more useful for identification purposes the principal function of the thin-section method in such circumstances is to provide information on the distribution, orientation, or size of the crystals of the different constituents. 

ISO 1183-1 2004. Methods for determining the density of non-cellular plastics - Part 1 Immersion method, liquid pyknometer method and titration method. 

For frequencies from 50Hz-lMHz the air substitution (Lynch method) or liquid immersion methods are generally used. BS 7663 gives details for air substitution and both two and one fluid immersion methods. ASTM D153149 specifies the same single immersion method as Method C of BS 7663. 

The bulk density of target materials was measured using the water immersion method. 

The porosity of the sialon ceramics was determined using a combination of the water immersion method and the image analysis technique. The porosity of the rest of the materials was either obtained from the manufacturers data sheet (SiC-C and SiC-S) or quoted from literature (SN-F and SN-C) (Becher et al., 1998). 

Laboratory Corrosion Test. The laboratory test procedure for the determination of corrosion rates of coal slurry used in this study was adapted from the method developed by Bomberger (26). The corrosion rates were determined by using ASTM Standard Corrosion Test, also known as the Total Immersion Method (27). The Bomberger technique consists of keeping coal slurry in suspension in a two-liter reaction vessel at a constant temperature. The corrosion rates are determined either by actual weight loss of steel coupons... 

The ASTM Corrosion Test procedure by Total Immersion Method requires that all specimens in a test series should have the same dimensions when comparisons are to be made. In these experiments, carbon steel was used representing the pipeline material. The coupons were cleaned, polished and weighed. Coal-water slurry, 10 to 40 weight percent, was used in the corrosion tests. For the coal-water slurry the intitial pH of the medium varied from 2.3 to 2.6 and the test series containing the nutrient media, the microorganisms and the inhibitors the pH varied from 2 to 2.5. Specimens were immersed in the reaction vessel maintained at a constant temperature of 86°F for 72 hours or the specified time. The coupons were removed, washed with deionized water, dried and weighed. The loss in weight of the specimen, before and after the test was attributed to corrosion. 

Fig. 5. Apparatus used to measure optical loss by the nondestructive immersion method ol Teng [184]...

Turner JS, Cheng YL (2000) Preparation of PDMS-PMAA Interpenetrating polymer network membranes using the monomer immersion method. Macromolecules 33( 10) 3714—3718... 

Immersion method—the assembly is immersed in a tank or water, and the water acts as a coupling mechanism for the ultrasonic signal. 

Bonded structures that are ultrasonically tested by the immersion methods often use a C-scan recorder to record the test. This recorder is an electric device that accepts signals from the pulser-receiver and prints out a plan view of the part. The ultrasonic search unit is automatically scanned over the part. The ultrasonic signals for bond or unbond are detected from built-in reference standards. C-scan NDT techniques are used extensively by aircraft manufacturers to inspect bonded parts. 

A first distinction must be made between the methods which use one sample for each point on the adsorption isotherm (i.e. immersion methods) and those using a single sample through which the solution of increasing concentration is allowed to flow (i.e. flow-through methods). A critical outline of most of these methods is given by Everett (1986). 

Immersion methods. These are the oldest and the easiest to apply with conventional bench-type equipment but may suffer, as we shall see, from a lack of accuracy or from a large sample consumption. 

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