Method water displacement

It was established that the newly developed CT unit has a spatial resolution of about 2 2.5 nun. This is quite acceptable given the size of the column used in this study. The solid fraction as determined by CT scan was about 2.5%, which was close to the value of 3% as determined by water displacement method. 

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. 

In order to calculate the density of a material, you need to know its mass and volume. Both of these properties can be easily measured in the laboratory, using the methods described in Lesson 2-2. Let s imagine that you place a rock on a balance to measure its mass and find it to have a mass of 22.516 g. You then use the water displacement method to determine the volume of the rock, which you find to be 7.84 cm3. You would then use the density formula to find the density of the rock, as shown here ... 

Gases from bubbling hot springs can also be sampled using the water-displacement method as described by Craig (1953), Mazor and Wasserburg (1965) and Kennedy et al. 

In fact, the derived SI unit for volume is the cubic meter. It is easy to visualize a cubic meter imagine a large cube whose sides are each 1 m in length. The volume of an irregularly shaped solid can be determined using the water displacement method, a method used in the MiniLab in this section. 

Explain Why can t you use the water displacement method to find the volume of a sugar cube ... 

Describe how you can determine a washer s volume without using the water displacement method. Note, that a washer is similar to a short cylinder with a hole through it. 

The mean bulk densities of foams were determined by measuring the weight and volume of specimens that had a length of 50 mm prepared by freeze-cutting. The diameters were measured by a video camera. The volumes of some samples were estimated by a water displacement method. 

The volumetric expression does not seem very valuable unless the sample volumes are carefully controlled, with the nonabsorbing portions of the sample kept to an absolute minimum. In addition, the problem of determining volume is compounded by the tendency of some bark types to trap air bubbles in standard water-displacement methods (Brodo, 1968). 

The void fraction was used to characterize the foam samples. The foam density was determined by the water displacement method (ASTM D792-00). Samples were taken from regions near the gate, at the center, and near the end of the injection-molded part. The expansion ratio O is equal to the ratio of the bulk density of HDPE/talc compounds, po, to the measured density of the foam sample, Pf. The void fraction was calculated as follows ... 

The quantitative analysis procedure involves benz extr of TNT, water extr of AN, and taking of the A1 content as insol residue. Moisture content is detd by the Karl Fischer method described in ASTM Method E203-62, except that 8 to lOg samples are added to methanol. Specific gravity is detd by water displacement, and workmanship by visual examination... 

If the resin were insufficiently dried, the moisture present could cause voids within the molded part. This happens when the water evaporates and leaves open spaces. One effect of voids can be a lower bulk density. Bulk density was measured by the displacement method in accordance with ASTM D792 [7], and was found to be substantially equivalent for the two samples, as shown in Table 12. 

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. 

Nguyen et al. [205] designed a volume displacement technique that was used to measure the capillary pressures for both hydrophobic and hydrophilic materials. One requirement for this method is that the sample material must have enough pore volume to be able to measure the respective displaced volume. Basically, while the sample is filled wifh water and then drained, the volume of water displaced is recorded. In order for the water to be drained from fhe material, it is vital to keep the liquid pressure higher than the gas pressure (i.e., pressure difference is key). Once the sample is saturated, the liquid pressure can be reduced slightly in order for the water to drain. From these tests, plots of capillary pressure versus water saturation corresponding to both imbibitions and drainages can be determined. A similar method was presented by Koido, Furusawa, and Moriyama [206], except they studied only the liquid water imbibition with different diffusion layers. 

Hon et al. [34] describe a simple piece of equipment for the determination of down to 80 pg/1 of mercury by AAS using a static cold vapour procedure. In this method [35], the sample was digested with the sulfuric acid, a measured portion pipetted into the reduction vessel, and the vessel immediately capped. The reductant, comprising 1% stannous chloride, was introduced. The evolved elemental mercury in the headspace was then introduced into the absorption cell by water displacement. Maximum sensitivity is obtained when the volume of the displaced air is equal to the internal volume of the absorption cell, and the mercury solution is 9 M in sulfuric acid. The peak absorbance at 253.7 nm exhibited a marked decline for hydrochloric acid concentrations above 1.5 M and for nitric acid concentrations above 3 M. The calibration graph obtained for mercury(II) in 9M sulfuric acid is linear from 0 to 17ng/ml, and the sensitivity is 0.08 ng/ml. A windowless absorption cell can also be used with a narrower linear calibration range. 

Laboratory-based methods of pore water displacement are designed to approximate diffuse water in quasi-equilibrium with the soil solid phase. Methodologies for obtaining unaltered soil pore water in a laboratory setting may be broadly defined as displacement techniques and comprise... 

Ammonia is a polar molecule and will dissolve in a polar substance like water. This means that water displacement is a poor method for the collection of ammonia. 

Body density (D0) is the ratio of body weight (BWg j.) to body volume. Body volume can be measured by water displacement or helium dilution, but the method of choice is underwater weighing (BWu2q) with corrections for the density of water (DHh2q) nd residual lung volume (RV) (40). Density is then estimated as follows ... 

Experiment 17. — Method Weigh the volume of water displaced by generating a known weight of the gas. 

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