Consolidated specimens

The data shown in Figure 7.15 were obtained from two-ply T300/P1700 unidirectional specimens that were compression molded in a 76.2 mm (3 in.) square steel mold. The cross-sections of the consolidated specimens were examined by optical microscopy and the degree of intimate contact was determined as the amount of the interply region that was in contact divided by the total area of the cross-section. Additional details of the experimental procedures are given in Reference 22. 

In triaxial testing, disturbance effects may be reduced by consolidating specimens to pressures well above the in-situ effective stresses prior to shear. The resulting strengths are obviously higher than the in-situ strengths. However, the strength parameters, C and X, and the pore pressure parameter. A, more closely approximate the field parameters than would parameters obtained from an unconsolidated, disturbed sample. Ladd and Lambe (1963) discuss this procedure in detail. 

Figure 6 shows a SEM micrograph of the compacted M50 steel specimen. By comparing the Figure 6 (SEM micrograph) with the corresponding EDAX spectra (Figures 7(a)-(d)) the compact shows a uniform microstructure with scattered Cr-rich precipitations. The specimen is 100% dense. The carbon and oxygen content of the consolidated specimen was found to be 0.54% and 4.1% respectively.

Sonochemically Prepared Nanostructured Iron. The consolidated iron pellet had a homogenous microstructure as confirmed by SEM taken at lOOX magnification (Figure 10) and it had a density of 100%. The carbon and oxygen contents were determined to be 0.05% and 1.1% respectively. In the XRD spectra the major peaks were assigned to the a-Fe phase and line broadening analysis revealed the average crystallite size in the consolidated specimen to be 40 nm. 

The application of the model to electrical measurements of systems consisting of clays and electrolyte solutions is then discussed. Dispersions (at 10-50 MHz) of consolidated specimens prepared by equilibrating different clays are reported. Interpretation of these measurements in terms of the model parameters exhibits meaningful variations of the values of the dielectric constants and conductivity of the solid clay phase with the nature of the clay, the electrolyte solution, the degree of consolidation of the aggregate and with the soil fabric. 

Note-. Anomalous decrease in strength values for specimens from concrete mixes of lower slumps attributable to mix thixotropy. Identical minimal consolidation was used for both high and low-slump mixes. 

The degree of bonding analysis has been verified for both compression molding and online consolidation of thermoplastic composites. In these studies, composite test specimens were consolidated under controlled processing conditions. The most common types of tests performed to measure the interply bond strength were the interlaminar (short beam) shear test [21,25] or the lap shear test [12,21,26]. 

Can the dielectric constant (K) of BT with a particle size of less than 200 mn be increased As stated earher in the background section, the K values need to be higher for embedded capacitor apphcations. How does the tetragonality in terms of the c/a ratio of the BT unit cell relate to the K of the particles The K values of BT-08 powders treated chemically were measured for the test specimens of BT-08 powder consolidated by polyvinyl butyral (PVB) binder with silver electrodes and by being placed under a Hewlett-Packard LCR meter. Our preliminary... 

Shock consolidation is known as a technique to produce the bulk materials from powders. However, it was hitherto difficult to obtain sound specimens without any cracks and/or central hole by using an axisymmetric explosive consolidation technique. 

The thickness of the consolidation state reduced to about 11/19. in Zr02/Ni, and 11/16 in Zr02/Al203 system compared with the tapping state. From macroscopic observations, no cracks were found in the specimens and continuous compositional change were confirmed. 

The so-called shear cells are used for direct shear tests, where the powder specimen is consolidated in the vertical direction and then sheared in a horizontal plane. There are basically two types of shear cells in use today the Jenike shear cell (sometimes referred to more generally as the translational shear box) and the annular (or ring) shear cell (the rotational shear box). As the equipment needed is highly specialized (and hence outside the scope of this Guide) and as manufacturers instructions are usually adequate, the following contains only an outline description of both the hardware and the test procedures. 

Fig. 17 shows the Jenike shear cell in a schematic diagram a circular (internal diameter 95 mm), open-ended shear box is split horizontally, the base is immobile and the ring can slide freely in the horizontal direction. The normal stress, which is applied via the lid, is first used to consolidate the specimen and then to load it during test. 

A standard procedure (including twisting and preshear) is used to fill the shear cell with a powder specimen consolidated in some reproducible manner. 

The principle of these testers is that the specimen can be subjected to controlled stresses in two orthogonal directions (biaxial testers) or three orthogonal directions (triaxial testers). In the case of the triaxial testers, two of the orthogonal stresses are usually equal, normally generated by liquid pressure in a pressure chamber. The specimen is placed in a cylindrical rubber membrane and enclosed by rigid end cups. The specimen is consolidated isotropically, i.e. by the same pressure in all three directions which leads to volumetric strain but little or no shear strain. This is followed by anisotropic stress conditions, whereby a greater axial stress is imparted on the specimen by mechanical force through the end cups. In the evaluation of results it is assumed that the principal stresses act on horizontal and vertical planes, and Mohr circles can be easily drawn for the failure conditions. 

Uniaxial Compression - Williams Method This method was developed by Williams, Birks and Bhatta-charya24. A compact is first formed in a split mould by applying an axial compressive force, the mould is then removed to leave a cylindrical specimen with its axis vertical. The compressive vertical stress needed to cause failure of the specimen is then found and this is the unconfined yield stress for the consolidating stress used in the compaction of the specimen. The failure function is found by forming a number of compacts under different consolidating stresses and finding the unconfined yield stress for each specimen. 

The Standard recommends plotting of the deformation of the specimen (as thickness of the specimen, as strain or as void ratio) as ordinate on a linear scale and the corresponding applied pressure in kN/m2 as abscissa on a logarithmic scale. From this, the coefficient of volume compressibility or the coefficient of consolidation may be evaluated as specified in the Standard. 

The specimen volume needed for analysis is minimal (e.g., 5pL), the dead volume in a specimen container is minimized, and the instrument has a smart probe as described above. Evaporation control is possible with lids of some kind, and a variety of different types of specimens, e.g., serum, plasma, urine, cerebrospinal fluid, and other body fluids can be accommodated on the same instrument. Obviously, the menu of enzyme tests must be broad enough to consolidate the testing on as few work stations as possible. 

In the cement concrete industry the recommended practice is to consolidate low slump mixes by vibration and high slump mixes with hand tools. For example, ASTM Method C 192 (6) specifies consolidating test specimens by vibration if the slump is less than 1 in. Relationships between workability and ease of placing sand-asphalt-sulfur mixes are being evaluated on various field projects to assess the workability requirements for mix placement with various types of equipment. 

For sample preparation, a clay slurry usually is consolidated to a void ratio of about 2.0 to 3.0 in cylinders at a maximum consolidation pressure of 200 kPa. The cylinders may serve also as the electroosmosis cells. Some variation in water content occurs across the specimens prepared in this manner and irregularities in consolidation/compactlon cause fairly large variations in the typical electrokinetic parameters that are monitored. It is advisable always to test a minimum of two or more samples in view of this. Some physical characteristics of Georgia kaolinite are presented in Table 1. 

Films dried for 30 days at 50°C showed normal values of Tg for Acryloid B72 and only a trace of retained solvent. For Butvar B98 the solvent removal was not as complete. The data also show that the solvents with higher boiling points (i.e., ethyl acetate and the ethanol-toluene mixture) are more diflScult to remove than acetone or methanol. When the same process of drying at 50°C was applied to wood specimens treated with consolidants, the Butvar B98 specimens dried at the elevated temperature had greater improvement factors than those dried at room temperature, whereas for Acryloid B72 the opposite was true (i6). The data of Table II would have indicated improvements connected to drying at elevated temperature for both resins. 

We assume mesoscale and microscale domains are periodic (Figure 5). Let ar , and jc be coordinate systems defined in macro-domain 2o, meso-domain Qi and micro-domain If we perform a laboratory seepage/consolidation test on a typical Japanese bentonite, Kunigel VI, the macroscale specimen is of scale lO m, the mesoscale quartz grains are of lO m, and the microscale clay minerals are of 10 m. So, we estimate the scale factor =10 , and introduce the relations x = x°/z, x = x /e. 

---