Solids measurement

Fest nass, n. solid measure, -punkt, m. fixed point fixed target. 

Korper-mass, n. solid measure, cubic measure, -oberflache, /. body surface, -pflegemittel,... 

Figure 3.6 compares iso-pH permeabilities of ketoprofen at various pH values in a 2% DOPC-dodecane model (open circles) and the 20% soy lecithin with SLS in the acceptor compartment (filled circles, data in Table 3.5). In the presence of the latter negatively charged lipids (with the make-up similar to that of BBM in Table 3.1), ketoprofen is intrinsically more permeable, by a factor of 17. The UWL limit, indicated by the solid curves in low-pH solutions, and consistent with the permeability Pu 19.8 x 10-6 cm s 1 (log Pu —4.7), masks the true intrinsic permeability of the membranes, P0. However, it is possible to deduce the membrane permeability if the pKa is known. In Fig. 3.6, the bending in the dashed (calculated) curves at pH 4 corresponds to the pKa of the molecule. Due to the UWL, the point of bending is shifted to higher pH values in the solid (measured) curves. The difference between the apparent pKa (pK 5.3 for DOPC and 6.3 for soy) and the true pKa (4.12) is the same as the difference between log P0 and log Pu [23],... 

Forsman, M. (1998) Gastric emptying of solids measured by means of magnetised iron oxide powder. Medical and Biological Engineering and Computing, Jan. 2-6... 

Figure 9.7 Observed increase in solid-water distribution ratios for the apolar compounds, tetrachlo-romethane (0) and 1,2-dichIoro-benzene (A) with increasing organic matter content of the solids (measured as organic carbon, /oc, see Eq. 9-21) for 32 soils and 36 sediments. Data from Kile et al. (1995).

Solids with high ionic conductivity have been prepared from KI and Agl e.g. KAg4I5. The rubidium salt was isostructural with this and had somewhat better handling properties, being less sensitive to the effects of moisture, which caused decomposition to Agl and M2AgI3. RbAg4I5 was found to have the highest temperature specific electrolytic conductivity, 0.27 ( 2 cm)-1 of any solid measured. This and other iodide-based solid electrolytes were recently reviewed.379... 

Thus a measurement of the ultrasonic velocity and density can be used to determine the adiabatic compressibility (or bulk modulus) of the material. For homogeneous solids measurements of the compression and shear velocities can be used to determine the bulk and shear moduli (see section 2.4). The Young s modulus of rod-like materials (e.g. spaghetti) can be determined by measuring the velocity of ultrasound. 

Solids also have surface tension because molecules on the surface of a solid particle are subject to fewer attractive forces than molecules in the bulk of the solid. Measurements of the surface tension of solids (usually called the surface energy) are difficult because solids are rarely pure and smooth on the molecular scale. 

The repetition of microelectrode measurements on many different locations yields conductivity maps of the surface-near regions of inhomogeneous solids. Measure-... 

The surface free energy of the solid measured from condensed state will be later discussed in the section handling chromatographic experiments at finite dilution (or concentration). 

Contact angle — The contact angle is the angle of contact between a droplet of liquid and a flat rigid solid, measured within the liquid and perpendicular to the contact line where three phases (liquid, solid, vapor) meet. The simplest theoretical model of contact angle assumes thermodynamic equilibrium between three pure phases at constant temperature and pressure [i, ii]. Also, the droplet is assumed to be so small that the force of gravity does not distort its shape. If we denote the - interfacial tension of the solid-vapor interface as ysv. the interfacial tension of the solid-liquid interface as ySL and the interfacial tension of the liquid-vapor interface as yLV, then by a horizontal balance of mechanical forces (9 < 90°)... 

A measure of the oxidation/reduction capability of a solution (liquid or solid) measured with an -> inert electrode. For -> electrochemically reversible systems it is defined by the - Nernst equation. For -> electrochemically irreversible systems it is a conditional measuring quantity, i.e., depending on the experimental conditions. See also -> potential, - redox potential. 

For gas-solids two-phase flow, owing to the presence of solids, measurement of gas velocity is difficult. Zhang (1990) designed an isokinetic momentum probe to measure gas velocity with reduced experimental error caused by the presence of the solids. Figure 30 shows measured results of local gas velocity under various operating conditions. 

TABLE 4 Spreading Pressure (in I0 3 N/m) of Adsorbed Films on Solids Measured by Adsorption Experiments... 

Light (uv-visible-near-ir radiation) reflected back from a flat, highly polished surface of a solid measured in intensity as a function of varying wavelength. Measurements can be made using plane-polarized light, at normal incidence, and on oriented faces of single crystals... 

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