Liquid displacement method

Contact methods of measuring surface roughness (see Chapter 7) are not likely to be successful with uncured rubber because of its softness. It is unlikely that roughness needs to be known very precisely and a simple method has been given by Orlovskii et al139. The volume of a disc is calculated using the overall thickness measured on top of any irregularities and compared to the true volume measured by a liquid displacement method. 

APPARENT PARTICLE DENSITY is when the volume measured includes closed pores or bubbles of gas within the particle. This density is measured by gas or liquid displacement methods like the liquid or air pyknometers (see below). 

The liquid displacement method, described in ASTM D1531-62, is in fact the only proper method for accurate dielectric constant measurements on the thin (about 0.2 mm) foil samples. A gold plated ERA liquid cell with an electrode spacing of 1.435 inn was used for these measurements. The measuring... 

Three methods are common, viz, the liquid displacement method, the sink-float method and the density gradient column method. Each of these is a common, standard technique and is fully described in ISO 10119, 1992 (for the determination of the density of carbon fiber), and also in ASTM D 276-87 (reapproved in 1993), which in fact also refers to ASTM D 1505, ASTM D 792, and AATCC, Method 20 (1990) (Fiber identification), each of which deals with the above techniques. ISO 10119 is a very good and concise description of the techniques. However the measurement liquids specified in ISO 10119 of ethanol, methanol, acetone, tricloroethane, and carbon tetrachloride, although suitable for carbon fibers, are not at all suitable for the general range of textile polymers, with the exception perhaps of ethanol and methanol. ASTM D 276 87 recommends the use of / -Heptane for universal application, except, of course for the olefins, such as polyethylene. A range of typical fiber densities is given in Table 4. 

The liquid displacement method for determination of the pore size distribution was already introduced in the early century by Becboid [17] and Erbe [18] and further developed by Munari [19,20]. This method is similar to the gas flow bubble-point method (see IV. 3.1.2) method. Thediffeience is that instead of agas aliquid is used to displace a second liquid which has already been present in the pores of the membranes. Aschematic drawing is given in figure fV - 25. For this method two immiscible liquids are employed. One of... 

Liquid Displacement Gas Meter Provers. The Hquid displacement prover is the most prevalent standard for the caHbration of flow meters at low to moderate gas flow rates. The method consists of displacing a known volume of Hquid with gas (Fig. 2). Gas entering the inverted beU causes it to rise and a volume increment can be timed. Typical prover capacities are 1 m or less although capacities as large as 20 m are available. Accuracies can be on the order of 0.5% of actual flow rate. 

The principal experimental method used to measure the density of a solid is determination of the mass of liquid displaced by a known mass of solid. It is essential that the solid have no appreciable solubility in the liquid, that all occluded air be removed from the solid and that the density of the displacement fluid be less than that of the solid lest the solid float. Densities of crystalline solids also can be determined from the dimensions of the unit cell. Davis and Koch discuss other methods for measuring the density of liquids and solids such as hydrostatic weighing of a buoy and flotation methods. 

Various aspects of in vitro gas production test have been reviewed by Getachew et al. [33], and these authors reported that gas measurement were centered on investigations of rumen microbial activities using manometric measurements and concluded that these methods do not have wide acceptability in routine feed evaluation since there was no provision for the mechanical stirring of the sample during incubation. Another in vitro automated pressure transducer method for gas production measurement was developed by Wilkins [34], and the method was validated by Blummel and Orskov [35] and Makkar et al. [36]. There are several other gas-measuring techniques such as (i) Flohenheim gas method or Menke s method [37] (ii) liquid displacement system [38] (iii) manometric method [39] (iv) pressure transducer systems manual [40], computerized [41], and combination of pressure transducer and gas release system [42]. 

Guillaume et al. [69] presented a high performance liquid chromatographic method for an association study of miconazole and other imidazole derivatives in surfactant micellar using a hydrophilic reagent, Montanox DF 80. The thermodynamic results obtained showed that imidazole association in the surfactant micelles was effective over a concentration of surfactant equal to 0.4 pM. In addition, an enthalpy-entropy compensation study revealed that the type of interaction between the solute and the RP-18 stationary phase was independent of the molecular structure. The thermodynamic variations observed were considered the result of equilibrium displacement between the solute and free ethanol (respectively free surfactant) and its clusters (respective to micelles) created in the mobile phase. 

In a closely related study, Tung and Sun discussed the microwave-assisted liquid-phase synthesis of chiral quinoxalines [80], Various L-a-amino acid methyl ester hydrochlorides were coupled to MeOPEG-bound ortho-fluoronitrobenzene by the aforementioned ipso-fluoro displacement method. Reduction under microwave irradiation resulted in spontaneous synchronous intramolecular cyclization to the corresponding l,2,3,4-tetrahydroquinoxalin-2-ones (Scheme 7.71). Retention of the chiral moiety could not be monitored during the reaction, but after release of the desired products it was found that about 10% of the product had undergone racemization. 

Another way to extract pore water is to use a displacement method, which is usually applied in the laboratory. In this method, a solvent immiscible with water is applied to the soil in a column or centrifuge tube, and gravity or centrifugation is used to move the solvent through the soil, displacing pore water. The displaced water can then be separated from the immiscible liquid and analyzed. 

Hydrocarbon types were estimated using the substractive method of Poulson (15,16) for the fractions boiling above 175°F. The hydrocarbon compound composition of the C5-175°F naphtha was determined by gas chromatography. Paraffin and naphthene contents of the 175°-350°F naphtha and of the 350°-550°F light oil were calculated from mass spectra. Liquid displacement chromatography on Florisil was used to determine the amount of polar material in the 550°-850°F heavy oil. 

A quick method of determining density utilizes Archimedes principle, which states that the buoyant force on an immersed object is equal to the weight of the liquid displaced. A bar of magnesium metal attached to a balance by a fine thread weighed 31.13 g in air and 19.35 g when completely immersed in hexane (density 0.659 g/cm3). Calculate the density of this sample of magnesium in SI units. 

The buoyancy method relies on weighing the sample in air, wa and in a wettable liquid, wn> e.g. water of density pn. The weight of liquid displaced due to the volume of the sample is given by uynj = wa - wn and the apparent solid density1) ps, is then defined by equation 1 9... 

Our own investigations have concerned (a) liquid spreading on solids and the laws relating the equilibrium contact angle and the critical surface tension of wetting to solid and liquid constitution (26, 27, 28, 53, 54,62), (b) liquid/liquid displacement from solid surfaces (1,5), (c) the properties of adsorbed monolayers on solids and their relation to the monolayer retraction method (28, 54, 62), (d) the surface electrostatic potentials of adsorbed organic monolayers on metals (9, 10, 11, 58, 59), (e) the effects of surface constitution on adhesion and abhesion (60),... 

If you need to find the volume of a solid that is not a regular shape, you can often use what is called the water displacement method. Imagine that we wanted to find the volume of a nail. A nail isn t close enough to a perfect cylinder to consider using the formula for the volume of a cylinder, so how would we measure its volume We would make use of a real cylinder, a graduated cylinder. How can we find the volume of a solid in a vessel that is made to measure the volume of a liquid We could, theoretically, melt the nail, but we would have to get it too hot and the process would change its volume slightly. We have to come up with another plan. 

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