Archimedes method

Characterization.— The LSFTO powder was calcined at a series of temperatures (1250, 1300, and 1400°C) in air to investigate phase purity and densification behavior. X-ray diffraction (XRD) powder patterns are shown in Fig. 1. The sample is single phase after heating at 1250°C. At the higher sintering temperatures, the lines become sharper and the density increases. The density measured by the Archimedes method was 90.3% relative to theoretical value after annealing at 1400°C for 10 h. The XRD pattern sintered at 1400°C was completely indexed with a cubic unit cell with lattice parameter a = 3.898(8) A and V= 59.2(6) A3. The weak XRD peaks at 31, 43, 55, and 65° 20 are also from the perovskite phase and arise from a small amount of WL radiation in the incident beam. 

The bulk densities of all the materials were determined using Archimedes method (AS 1774.5, 1979). The Vickers indentation technique was used to measure the hardness in each case. The applied load in the Vickers hardness tests was 10 kg for silicon nitrides and sialons. However, using the same load produced severe lateral cracking in silicon carbides around indents, which prevented the accurate measurement of the diagonals of indents. Therefore the load was reduced to 0.3 kg for silicon carbide samples. 

The porosity of the resulting flat supports was measured after firing of AKP-30 and AKP-15 at respectively 1100°C and 1150°C with the Archimedes method by immersion in mercury. 

The porosity of AKP-30 (AKP-15) tubes, made with optimum [APMA] was 42.5% (43.2%) after firing at 500°C, measured with the Archimedes method by immersion in mercury. The sintered compacts had a porosity of 34.8% (34.5%). Their pore-size distributions, measured by mercury porosimetry are given in Figure 3. The mean pore radius was found to be 60 (92) nm. 

Fiber density. The density of a fiber can be measured by the same techniques as the ones used for conventional, bulk materials. The Archimedes method can be used in a straight forward manner to measure this simple but important property. One weighs the mass of a fiber sample in air and in a liquid of known density, for example, ethanol. Then the following expression gives the density ... 

Laboratory batches of compounded rubber samples were obtained from either Smithers Laboratories of Akron, Ohio, or Mare Island Naval Shipyard. Proper cure conditions were determined for each compound as per ASTM D 20845-79 through the use of a Monsanto lOOS oscillating disk rheometer. Samples used for experimental purposes were cured to 90% of optimum cure. Density was determined by Archimedes method. 

The Archimedes method has been used to determine the densities of fused... 

Although the original Archimedes method is sometimes called the method of the hydrostatic balance this name is now usually applied to the special balance devised by Hare and later by Mohr, and improved by Westphal and others. This is well known and need not be described in detail it is capable of giving accurate results (fourth decimal). 

Appendix 2—Geographic Information Systems.432 Appendix 3—Archimedes Method Goes... 

In this study 99.999% purity bismuth, antimony and tellurium powdered elements were used as starting materials. Hot pressing method was chosen as a sintering process. Hot pressing conditions were 753K, 400kgf/cm, for one hour. Typical sizes of hot-pressed specimen were 1 Omm( ) X 5mm and sliced into 1mm thick disk specimen. The density of specimen measured by Archimedes method were more than 98% of the ideal value. 

The microstructure observation of the sintered ceramics surface was performed by means of scanning electron microscopy (SEM, JEOL JSM 6400, Japan). The crystalline phase of sintered ceramics was identified by X-ray diflfaction (XRD, RIGAKU D/max 2.B) with CuKa radiation (X=l. 541SA at 40 kV and 30 mA) and scanned from 20° to 70° with scanning speed of 4°/min. The bulk densities of the sintered pellets were measured by the Archimedes method. The dielectric constant ( ,) and the quality factor values (Qxf) at microwave frequencies were measured using the Hakki-Coleman dielectric resonator method which had been modified and improved by Courtney The dielectric resonator was positioned between two brass plates. Microwave... 

In addition small-scale exposures at 870"C were used to study further the role of water vapour with 20 vol.-% and 30 vol.-% water vapour in air in an alumina tube furnace. Phase morphology was studied with scanning electron microscope (SEM). To distinguish between the glassy and crystalline phases some samples were etched in 2-% HF-solution. Phase composition was determined by a quantitative X-ray diffraction (XRD) analysis based on the internal standard, Cap2, method. The chemical composition of the amorphous phase in the binder was determined locally with EDS analysis in SEM. A bulk chemical analysis of the amorphous phases in binder was performed by Induction Coupled Plasma Mass-Spectrometry (ICP-MS). The samples were crushed powders of as-received and 500 h at water vapour bulk exposed (w) materials. The glassy phase was dissolved in HF-HNO3 solution. Open porosity, apparent and bulk densities of each specimen were determined by Archimedes method before and after the tests. 

Microstructures and morphology of the anode cermet before and after reduction were investigated by the S-4700 scanning electronic microscope. Thermogravimetric analysis (TGA) was used to confirm the green tape sintering parameters by TAS-100 TGA. Porosities of the Ni-GDC anode were examined by Archimedes method. 

C/min, followed to 1300 °C at a rate of S C/min and maintained for Ih, Finally, the speeimens were cooled down to lOOOTl at IO°C/min, the electric power was then switched off cooling the furnace to the room temperature. Microstructures were observed by scanning electron microscopy (SEM, Model JSM-6700F, JEOL, Akishima, Japan). The porosities and bulk densities were measured by the Archimedes method in distilled water. 

Figure 2 show the total porosity of the samples, determined by Archimedes method. While both types of starch had the total porosity of the sintered samples in the range of 51-61%, the tapioca starch seemed to cause a lower amount of porosity. This might be corresponded to the different characteristics as a gelling agent from different kinds of starches. Unlike com starch, tapioca starch normally becomes as a gel-like stmcture at lower temperature and at higher concentration [5]. 

The microstructures of the Ti02 sheet cross-section were observed by scanning electron microscopy (SEM), and the phase composition was confirmed by X-ray diffraction (XRD). The porosities of the samples were determined by Archimedes method. 

The density was measured by Archimedes method. The flexure strength were tested by three point bending way using an INSTRON 5566 test machine (Canton, MA, USA) with a span of 24 mm and a crosshead speed of 0.5 mm/min. The work of fracture was obtained from the characteristic area under the stress-displacement curve divided by the cross section of the specimen. In order to determine the work of fracture effectively, we defined the characteristic area which started from initial point to the 60% drop of the curve. After the test, the silicon volume content was calculated... 

The relative density, porosity and the strength of the porous AI2O3 ceramic is about 61.59 %, 37.04 % and 31.0 MPa, respectively. The porosity calculated from the relative density is almost the same as the date given by the Archimedes method. Therefore, it is reasonable to suppose that most of the pores are open, which is useful as the scaffolds. The porosity and strength of the porous AI2O3 ceramic are both suitable for hard tissue repair applications. 

Fig. I presents the appearance of 3at%Nd Lu203 transparent ceramic sample (1.4mm thick) which has been polished on both sides. The sintered specimen has a diameter of 15mm and a thickness of 1.4mm. The relative density measured by Archimedes method reached 99.8% theoretical value, indicating a nearly full density. As this photo revealed, the letters under the sample can be seen clearly.

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