Other Reference Fluids

Marrucho and Ely developed a saturation boundary based method to evaluate the shape factors that is easily transferable between reference fluids. The method is based on the Frost-Kalkwarf vapour-pressure equation and the Rackett equation for saturated-liquid densities. Using these relations and eqs 6.30 one finds for the 6 shape factor 

In deriving these equations, we have assumed that 6 is close to one and therefore In 0=0 1 and have defined AB = Bj-Bq and AC neglected the D term in the Frost-Kalkwarf equation 

Since the reference fluid parameters appear explicitly in the shape factor expressions, this formulation is easily transferable between reference fluids. In the supercritical region, Marrucho and Ely proposed a method of calculating the shape factors assuming that (pj=ZcfilZcj and that isochores were nearly linear, resulting in an expression for the 0 shape factor 

The superscript a indicates the isochore which intersects the reference fluid saturation boundary at pl = pho, ho = ZafiPcfilZcjpcj and j = (dpldT)p. The jc for the target fluid may be obtained from the Frost-Kalkwarf equation as 

As discussed in section 6.3.2, Mollerup analyzed common cubic equations of state, such as the Soave-Redlich-Kwong and Peng-Robinson equations in terms of separating them into a shape-factor correlation and an equation for the pure reference fluid. The shape factors obtained from the cubic equations of state have the advantage of being similar to the ones developed by the more complex correlation schemes outlined here, but are simpler to use, since they are density independent and can be used with any reference fluid. 

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Absolute viscosities are difficult to measure with capillary viscometers, but viscosities relative to some standard fluid of known viscosity, such as water, are readily determined. The viscometer is caHbrated with the reference fluid, and viscosities of other fluids relative to the reference sample are determined from their flow times. 

The definition of the heat-transfer coefficient is arbitrary, depending on whether bulk-fluid temperature, centerline temperature, or some other reference temperature is used for ti or t-. Equation (5-24) is an expression of Newtons law of cooling and incorporates all the complexities involved in the solution of Eq. (5-23). The temperature gradients in both the fluid and the adjacent solid at the fluid-solid interface may also be related to the heat-transfer coefficient ... 

The term exposure refers to the amount of drug entering the body, and various measures of observed or integrated drug concentrations in the plasma and other biological fluids (such as C min ss AUC). Response refers to a direct measure of the... 

Fickett in "Detonation Properties of Condensed Explosives Calculated with an Equation of State Based on Intermolecular Potentials , Los Alamos Scientific Lab Rept LA-2712 (1962), pp 34-38, discusses perturbation theories as applied to a system of deton products consisting of two phases one, solid carbon in some form, and the other, a fluid mixt of the remaining product species. He divides these theories into two classes conformal solution theory, and what he chooses to call n-fluid theory. Both theories stem from a common approach, namely, perturbation from a pure fluid whose props are assumed known. They differ mainly in the choice of expansion variables. The conformal solution method begins with the assumption that all of the intermolecular interaction potentials have the same functional form. To obtain the equation of state of the mixt, some reference fluid obeying a common reduced equation of state is chosen, and the mixt partition function is expanded about that of the reference fluid... 

Practicality has been an issue since many of the solvents referred to prior to 1994 have been quite expensive and the few others available have not had sufficient thermal stability to make them useful commercially. This chapter reviews our recent discovery of several commercially available cyclic perfluorocarbons as well as other halogenated fluids (and even carbon dioxide) as solvents for tetrafluoroethylene-containing polymers. We will describe solvation at atmospheric pressure, under autogenous conditions and under superautogenous... 

G62b. Grasbeck, R., Simons, K., Sinkkonen, I., Studies on gastric juice, saliva and other body fluids with special reference to immunoelectrophoretic cross-reactivity and vitamin Bj2-binding components. Protides Biol. Fluids, Proc. CoUoq. Brugge, 1693 11, 242-244. Elsevier, Amsterdam, 1964. 

Wettability. The wettability of the porous medium refers to its preference for one or the other fluid in becoming wet. It is defined as the tendency of one fluid to spread on or adhere to a solid surface in the presence of other immiscible fluids (7). In a rock-oil-brine system, it is a measure of the preference that the rock has for either the oil or the water. A water-wet rock is preferentially wetted by the water phase, and similarly for an oil-wet system, the rock primarily makes contact with the oil phase. 

The reference fluid which consists by TPT of non-bonded nitrogen atoms represents the so-called non-associated limit (NAL) of the hard molecular fluid. The nitrogen atoms interact as hard spheres with the diameter ra via the hard sphere pair potential. The density functional theoretical description of the NAL falls back on that which are used by the spherical DFT approach. The latter provides beside other a suitable description for the inhomogeneous hard sphere fluid. 

EN86 Boeyckens, A., Schots, J., Vandenplas, H., Senesael, F., Goedhuys, W. and Gorus, F.K. (1992). Ektachem slides for direct potentiometric determination of sodium in plasma Effect of natremia, blood pH, and type of electrolyte reference fluid on concordance with flame photometry and other potentiometric methods. Clin. Chem. 38, 114-118. 

As already described, the original sample is of importance. Serum or plasma can be employed with all systems. In the case of plasma, attention must be paid to the anticoagulant, since it may interfere with the analysis. So far, reference ranges for analytes measured in whole blood are known for a few parameters only. Other body fluids, such as urine or cerebrospinal fluid, can be used only with the Ektachem system and a few reagent carriers of the Reflotron system. The majority of reagent carriers or slides are only suitable for serum, plasma or whole blood. The use of dry chemistry in veterinary medicine poses special problems although results have been published, information is still lacking. 

Measurements of enzymes are used in medicine in two major ways Enzymes are measured in serum and other bodily fluids to detect injury to a tissue that makes the enzyme. Enzymes are also measured, often within a tissue, to identify abnormahties or absence of the enzyme, which may cause disease. In the first part of this chapter we discuss enzymes as markers of disease, and then describe conditions associated with abnormalities of enzymes in one readily available cell type, the erythrocyte or red blood cell. Many other abnormahties of enzymes exist, of course, and many are described in chapters of this book including Chapters 40 (Inherited Disease), 43 (Pharmacogenetics) and 55 (Inborn Errors of Amino Acid, Organic Acid, and Fastty Acid Metabolism). For descriptions of enzyme abnormalities associated with lysosomal storage disease, and tests for the related enzymes, readers are referred to the Chapter 40 Appendix that is located on this book s accompanying Evolve site, found at http //evolve.elsevier.com/Tietz/textbook/. 

The determination of PG is a commonly used qualitative method used to assess FLM in the United States. Measurement of PG was classically performed by thin-layer chromatography. It could be performed alone or in combination with other amniotic fluid phospholipids. The later test was loiown as a lung profile since its introduction in the early 1970s. Although thin-layer chromatography is still offered by some reference and hospital laboratories, most hospital laboratories use a rapid slide method for qualitative PG detection. Several enzyme-based tests for quantitative PG have also been published, but none is widely... 

The accepted reference method for determining chloride in blood serum, plasma, urine, sweat, and other body fluids is the coulometric titration procedure. In this technique, silver ions are generated coulometrically. The silver ions then react with chloride ions to form insoluble silver chloride. The end point is usually detected by amperometry (see Section 23B-4) when a sudden increase in current occurs on the generation of a slight excess of Ag. In principle, the absolute amount of Ag" needed to react quantitatively with Cl can be obtained from application of Faraday s law. In practice, calibration is used. First, the time required to titrate a chloride standard solution with a known number of moles of chloride (nci )s using a constant current I is measured. The same constant current is next used in the titration of the unknown solution, and the time r is measured. The number of moles of chloride in the unknown (ncr)u is then obtained as follows ... 

In one infant with the fulminating variant of the disease the level of ammonia in the cerebrospinal fluid was 114 / g/100 ml when the blood level was over 800 /xg/100 ml (L5, L9) (Table 3). The only other reference to ammonia levels in cerebrospinal fluid or blood was by Carton et al. (C3), who observed in a neonate with argininosuccinic aciduria that the ammonia levels in both blood and cerebrospinal fluid as judged by column chromatography were high or very high. 

This cell (Figure 6.8) is separated into two parts by an oblique dividing wall. One side is filled with reference fluid and eluate passes through the other. The deflection of the light beam changes when the refractive indices differ in both cells, i.e. some eluted sample is flowing through. 

The snow and frost described are almost assuredly of different morphology, particle size, and size distribution than the starting material Hannay and Hogarth studied salts such as cobalt chloride and potassium iodide. Incidentally, the reference to the precipitation of the solid is not an Isolated report of nucleation from a supercritical fluid. For example, many other references to snow, fog, fumes, and crystals formed during depressurization of a solution of a solute in a supercritical fluid have been made by researchers studying supercritical fluid solubility phenomena. 

As we related in the introduction to Appendix A, this patent should be read by everyone involved in research and process development using supercritical fluids. In his examples, Zosel describes results on neat solubility, separations of liquids and solids, fractionations, etc. A wealth of information is given on the performance of various gases, e.g., ethylene, ammonia, ethane, carbon dioxide, in dissolving a variety of compounds. Several interesting experiments carried out in a plexiglass autoclave are descrited, and certain phase separations are noted. Some of the information can be found in other references, of course, but not in such succinct form. It is of pedagogical value to reproduce one of the examples here. 

The analyte may be present in a variety of matrices such as plasma, serum, cerebrospinal fluid (CSF), urine, or other biological fluid, all of which contain a multitude of interfering factors that can impact the method s performance. As mentioned earlier in the chapter, LBA samples are not pretreated prior to analysis, thus calibrators and quality control (QC) samples should also be prepared in the study matrix to best mimic these samples and ensure accurate measurements. The ideal matrix (1) has low background signal in the assay (OD <0.1 for chromogenic end points), (2) has minimal or no analyte-like activity, (3) is devoid of interfering factors, and (4) demonstrates a response that is proportional to the concentration of the spiked analyte. Access to a prototype method using an assay buffer of defined composition as a reference helps to identify an appropriate matrix. 

Tabulated data of good accuracy (say better than 0.1%) for some or all of Vm. P and Z are available in a wide range of pressures and temperatures for protium and, to a lesser extent, deuterium. A comprehensive tabulated source is Vargaftik (1975). Other sources are discussed by Hemmes et al. (1986). The most recent, most comprehensive and generally most accurate source is contained in the commercially available National Institute of Standards and Technology (USA) Reference Fluid Thermodynamic and Transport Properties database (REFPROP, URLhttp //www.nist.gov/srd/nist23.htm), in which are embedded advanced equations of state for protium (Jacobsen et al., 2007) and deuterium (McCarty, 1989). 

Figure 4-17 illustrates the basis on which calculation of the viscosity index of oils other than the reference fluids rests. The curve marked Series L is the reference plot of the viscosities in centistokes at 100 C of the standard naphthenic oils of viscosity index zero against the viscosities of these oils at 40 C. The curve labeled Series H is a similar reference plot for the standard paraffinic oils of viscosity index 100. To compute the viscosity index of a new "unknown" oil, direct determinations of its viscosity at 40 and at 100 C are required. The formula below is then used for computation ... 

In addition to the equations of state listed in Table 14-9, other useful equations of state have been proposed. In order to cover the whole range of reduced temperatures Tr and reduced pressures Pr of practical interest in hydrocarbon processing, Lee and Kesler39 proposed the use of two equations of state similar in form to the BWR equation of state, one for a simple fluid and one for a reference fluid. The Lee-Kesler correlation also makes use of the acentric factor. 

The determination of noble gases in water can be divided into three successive analytical steps (1) noble gas extraction from the water, (2) purification and separation of the extracted noble gases, and (3) quantitative (mass spectrometric) analysis. For extended discussions of methods for noble gas analysis in waters (and other terrestrial fluids) the readers are referred to Clarke et al. (1976), Rudolph (1981), Bayer et al. (1989), Stute (1989), Groning (1994), Ludin et al. (1997), and Beyerle et al. (2000a). 

In this study the BWR-Starling (BWR-S) (20,21) equation of state was used, primarily because it has been fitted to a wide range of pure components. For some components there are other equations which represent isochoric behavior much better. However, the effect of the HSE procedure for mixtures when pure-component equations of state are known is to generate a more rigorous composition dependence in the reference-fluid equation of state. The BWR-S equation for mixtures has an empirical composition dependence which works well in some cases, particularly for hydrocarbon mixtures, but not so well for others, especially when nonhydrocarbons are involved. When the BWR-S equation is used for all pure component properties, it is interesting to compare the theoretically based composition dependence induced by the HSE theory with its empirical form in the BWR-S mixture equation. 

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