Buoyancy method

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... 

Sample Sample code Apparent density (Buoyancy method) (gem 3) Apparent porosity (%) Theoretical porosity (%) True density (Helium pycnometry) (gem 3)... 

Various techniques, such as intrusion methods, image analysis and weight determinations are used to provide estimates of the porosity and the distribution of pore sizes within a tissue scaffold. This preliminary study of the structural features of particulate-leached PCL scaffolds has shown that reliable measures of porosity can be obtained from simple weighing measurements (Buoyancy method). 

Thus gas adsorption provides essentially important information on the nanopores from the sub-nanometer level, which is often inherent to a specific molecule. Also the density measurement is necessary for the exact porosity evaluation. The accurate particle and true densities give close porosity. Even He molecules are adsorbed in small nanopores at room temperature and thereby the He replacement method is not fit for determination of the particle density. Authors developed the high pressure He buoyancy method until 10... 

Density gcm Buoyancy method, calculated from data in 0.8683-0.8787 (2)... 

Density measurements. Polymer densities were measured using the neutral buoyancy method using a pyconometer (75). The neutral buoyancy medium was a mixture of tetrachloromethane and hexane. 

Figure 12,4 Density and fractional free volume of PebaxVPEC as function of volume fraction of PEC determined by additive model and buoyancy method [modified plot from ref 24]...

Figure 61. Aluminum oxide ceramic, BF. Porosity determined by buoyancy method 3.6% (a) After preparation at 250 rpm. Porosity determined by image analysis 5.4%. (b) After preparation at 750 rpm. Porosity determined by image analysis 3.7%.

The density of the polymers was measured from samples taken from the supplied sheets in a laboratory precision weighing scale equipped with a density determination kit. The experimental technique utilised in the determination of the densities was based on the Archimedes principle (or buoyancy method), which states that a body immersed in a fluid apparently loses weight by an amount equal to the weight of the fluid it displaces. 

In the buoyancy method, displacement bodies measure levels in liquid containers. By measuring the difference in weight of a partially submerged body at various degrees of submergence, one may determine the level of the liquid in which it is... 

Density and specific volume of mesophases are measured under atmospheric pressure with pycnometers [17-22], dilatometers [16, 23-25] (e.g., differential scanning dilatometers, DSD [26-31]), with a buoyancy method [32], and with a vibrating device, known as a digital precision density meter system, or densitometer (Anton Paar K.G.) [33-38], Devices for high-pressure measurements of specific volumes have been described by Kuss [39,40] and Ddrrer et al. [41], but were also mentioned earlier [42], More recently, a device for simultaneous... 

Bridgman flexible bellows with slide wire 369 Brillouin scattering 719-726 broken aspects, textures 439 bubble domains, ultrasonic fields 557 building blocks, synthesis 98 bulk fluids, molecular modelling 77 bulk SHG, optical properties 577 bulk systems, large-scale simulation 83 buoyancy method, density measurements 332 Burgers vectors, defects 425,447... 

More precisely, the apparent density is determined by the hydrostatic (buoyancy) method according to standards ASTM-C-20-00, DIN EN 993-1, and ISO 5017 [16, 25, 26]. The apparent density is calculated according to... 

DIN 51918-1999. Testing of carbonaceous materials - determination of bulk density by buoyancy method and the apparent porosity by impregnation with water. 

Fig. 155, p. 334, shows the density of TmxSe at room temperature as a function of x, determined with the buoyancy method, together with theoretical values and calculated for the following defect models 1) vacancies, 2) interstitial defects, 3) antisite defects (Tm occupies both cationic and anionic Schottky vacancies), Kaldis, Fritzler [1, p. 125], [2, p. 83], Fritzler, Kaldis [3], Fritzler et al. [4]. The discontinuity at Tmo.sySe is attributed to the formation of the TmsSe superstructure. The difference between experimental and calculated densities for the compositions Tmo.sySe to Tmi oSe is explained by the increasing number of Schottky vacancy pairs. The existence of both iSchottky pairs and antisite defects is assumed between Tm oSe and Tmi oeSe. Selected numerical values of the experimental density as a function of composition ... 

Buoyant Force. Density of fluid may be measured by the buoyant force of the fluid upon a submerged plummet. This method is ideally suited for static laboratory use and involves relatively simple equipment. The drawbacks of the buoyancy method are slow response, poor sensitivity, and the need to make a remote reading of a mechanical displacement. 

Where n is the number of cells in the defined area A, and yOp and pf are the density of the unfoamed and foamed polymer, respectively. The foam density was measured by the buoyancy method. The relative foam density was calculated as the ratio of the foamed density to the density of unfoamed sample. 

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