Disk flow test

In the disk flow test, a measured amount of room-temperature compound is placed on the lower half of the mold and the mold is closed and then reopened as soon as the compound is cured. The molded disk is then measured for diameter and thickness. Either the thickness of the disk or the diameter of the disk can be used as a gauge. The thinner the disk or the larger the diameter, the softer the flow. The thicker the disk or the smaller the diameter, the stififer the flow. 

For flow tested combinations, see a few typical data in Table 7-12. Note, for example, that using a Continental disk reverse acting knife blade rupture disc with a Crosby JOS/JBS pressure relief valve that the combined effect is to multiply the rated capacity of the Crosby valve by a multiplier of 0.985 for a set pressure in the 60-74 psig range... 

Before being used for flow experiments, each disk was tested with helium for acceptability. The rate of helium flow at 10-cm. pressure gradient across the disk was measured at several mean pressures between 5 and 50 cm. Unless the mass of gas passing per unit time was constant—i.e., the flow through the disk followed Knudsen s law—the disk was rejected. About one disk in ten passed this test the others showed increased flow at high pressures. 

Disk flow II (test and mold) (Fig. 2.24). With the diameter of the disk being used as the gauge, the molded disk is placed on a target of concentric... 

Dental stone is generally used at a water—powder volume ratio of about 30 parts water to 100 parts of stone. The mix is not easily poured, but can flow readily under mechanical vibration. The physical property requirements include a setting time of 10 3 min fineness of powder, where 98% should pass a number 100 sieve (ca 0.15 mm) and 90% pass a number 200 sieve (ca 0.07 mm) linear setting expansion at 2 h of <0.20% compressive strength at 1 h of 20.6 MPa (2987 psi) and consistency such that the slump test disk is 30 2 mm diameter. 

The coefficient of discharge, Ko, is the actual flow divided by the theoretical flow and must be determined by tests for each type or style and size of rupture disk as well as pressure-relieving valve. For rupture disks, the minimum net flow area is the calculated net area after a complete burst of the disk, making allowance for any structural members that could reduce the net flow area of the disk. For sizing, the net flow area must not exceed the nominal pipe size area of the rupture disk assembly [1]. 

Over the twentieth century, the mbber industry has developed special rheometers, essentially factory floor instmments either for checking process regularity or for quality control purposes, for instance, the well-known Mooney rheometer (1931), the oscillating disk rheometer (1962), and the rotorless rheometer (1976). All those instmments basically perform simple drag flow measurements but they share a common feature During the test, the sample is maintained in a closed cavity, under pressure, a practice intuitively considered essential for avoiding any wall slip effects. Indeed it has... 

When using USP 23 Apparatus 3 (reciprocating cylinder), USP 23 Apparatus 4 (flow- through cell), or USP 23 Apparatus 7 (reciprocating disk) the above dissolution testing conditions should be modified accordingly. 

Experimental studies to construct a binding curve will be described at pH 4.5. To prepare the gel filtration column, obtain a chromatography column (about 1.5 X 15 cm). It should be equipped with a porous glass disk and a stopcock at the bottom to control flow rate. Clamp the column to a ring stand and connect the bottom tubing to a fraction collector containing 50 test tubes. If... 

The separation of protein test mixtures on very short C 8 columns yielded surprising results (Fig. 18). The resolution obtained with a 6.3 x 4.6 mm column was about 2.25 or 2.22 times better than with a 45 x 4.6 mm column when the flow rate was low (0.25 or 0.5 ml/min, respectively) and the volumetric gradient rate large (16% B/ml). The gradient components were A water and B 2-propanol, both with 0.1% trifluoro-acetic acid (TFA)73). Even a column (better to say, a disk) 1.6 mm in length and 4.1 mm in diameter was effective in separating ribonuclease A, cytochrome C, and ovalbumin. Of course, the sample capacity of such a short column was very low 73). 

On a so-called micro laboratory disk (see Figure 4.33) the individual wells of the array and their sequence can be varied depending on the synthesis or analysis to be performed. Thus the function of the arrays can be readily changed with only the additional need to choose a suitable interface for monitoring and controlling the flow of fluids to the particular array being used and the test or synthesis to be performed [85],... 

Example 6.14 Squeezing Flow between Two Parallel Disks This flow characterizes compression molding it is used in certain hydrodynamic lubricating systems and in rheological testing of asphalt, rubber, and other very viscous liquids.14 We solve the flow problem for a Power Law model fluid as suggested by Scott (48) and presented by Leider and Bird (49). We assume a quasi-steady-state slow flow15 and invoke the lubrication approximation. We use a cylindrical coordinate system placed at the center and midway between the plates as shown in Fig. E6.14a. 

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