Depth of immersion

An equivalent formula fpr powders that are present as slurries in water removes the necessity for drying out the slurry. A specific gravity bottle is filled with water and weighed the water is replaced with the slurry under test and the bottle is re-weighed the difference in weights being AIV. The sample is then taken out of the bottle and used for the analysis. The equivalent formula is  

With the hydrometer technique, both density and depth of immersion vary with each reading. If the temperature is maintained constant at the hydrometer calibration temperature the density may be read directly from the hydrometer stem otherwise a correction needs to be applied [52]. 

It is clear that a hydrometer with a long bulb does not measure density at a point it only measures the average density of the suspension displaced by the hydrometer. The difficulty lies in determining the point of reference below the surface to which this density refers, for when the hydrometer is placed in the suspension the liquid level rises in the container, thus giving a false reference point (Fig. 7.13). 

If the cross-sectional area of the container is A, the depth to be used in Stokes equation, from geometrical considerations, is [53]  

Several workers, who claim that corrections have to be applied for the density gradient about the bulb, and the displacement of suspension by the stem, have challenged this simple formula. Johnson [54] for example, gives the sedimentation depth, in cm, as  

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According to the simple formula, the maximum bubble pressure is given by f max = 27/r where r is the radius of the circular cross-section tube, and P has been corrected for the hydrostatic head due to the depth of immersion of the tube. Using the appropriate table, show what maximum radius tube may be used if 7 computed by the simple formula is not to be more than 5% in error. Assume a liquid of 7 = 25 dyn/cm and density 0.98 g/cm. ... 

A number of potential sources of error must be taken into account. In the volumetric method the following items need attention (a) constancy of the level of liquid nitrogen (b) depth of immersion of the sample bulb ( S cm) (c) temperature of sample (monitoring with vapour pressure thermometer close to sample bulb) (d) purity of adsorptive (preferably 99-9 per cent) (e) temperature of gas volumes (doser, dead space), controlled to 01 C. 

In addition to non-Newtonian flow, the main correction necessary for concentric cylinder measurements is that on account of end effects. Because the inner cylinder is not infinitely long, there is drag on the ends as well as on the face of the cylinder. The correction appears as an addition, to the length, b. The correction is best deterrnined by measuring the angular velocity and torque at several values of b, that is, at various depths of immersion. The data are plotted as M/Q vs b, and extrapolation is made to a value of at M/H = 0. The quantity (/i + h ) is substituted for b in the various equations. 

Elntauch-refraktometer, n. immersion refrao-tometer. -tiefe, /. depth of immersion. Elntausch, m. exchange, bartering, elnteeren, v.t. tar. 

Improved plow steel and extra improved plow steel, bright and galvanized. Use a suitable solvent to remove lubricant. The wires then should be dipped in commercial muriatic acid until thoroughly cleaned. The depth of immersion in acid must not be more than the broomed length. The acid should be neutralized by rinsing in a bicarbonate of soda solution. Fresh acid should be prepared when satisfactory cleaning of the wires requires more than one minute. (Prepare new solution—do not merely add new acid to old.) Be sure acid surface is free of oil or scum. The wires should be dried and then dipped in a hot solution of zinc-ammonium chloride flux. Use a concentration of 1 lb (454 g) of zinc-ammonium chloride in 1 gal (3.8 L) of water and maintain the solution at a temperature of 180°F (82°C) to 200°F (93°C). 

This solution is used at room temperature. The broom should be immersed from 30 to 90 s. The depth of immersion in the solution must not be more than broomed length. The wires should then be dipped in clean hot water. 

Optimum depth of immersion depends on pitch-line speed. Deep immersion is permissible at low speeds because power losses from churning are low, but at moderate speeds the immersion depth should not be more than three times the tooth height. At the highest speeds, only the addenda of the teeth need be submerged (Figure 52.8). 

Figure 52.8 In a splash-fed gear the depth of immersion must be reasonably constant for all the gears, therefore the casing should incorporate stepped troughs for the oil...

Where constant depth of immersion is desired in spite of tidal action, it is necessary to support the test racks from a float or raft. 

A also depends on the depth of immersion of the electrodes up to a certain value and the electrodes should always be at such a depth that A is independent of it. In most modern instruments either the electrodes are constructed to have >4 = 1 cm or there is a facility for compensating for values of A other than 1 cm. For accurate work the cell constant is usually measured for each set of electrodes by a standard method (Lind, Zwolenik and Fuoss, 1959). 

For initiating expls only 0.01 g samples are prescribed. When the metal in the crucible reaches the desired temp, place the shatterproof-glass barricade in front of the apparatus, and lower (by means of a lever) the clamp to a point corresponding to the fixed depth of immersion of the cap in the molten metal. 

FIG. 6.10 Contact angle hysteresis (a) weighing a meniscus in a Wilhelmy plate experiment versus the depth of immersion of the plate (b) both the advancing and receding contact angles are equal (c) 6a > dr. 

With the foregoing ideas in mind, one characteristic of the adsorbed monolayer becomes apparent molecular orientation at surfaces. For a film of RX on water, the picture that emerges is one in which the polar groups are incorporated into the aqueous phase with the hydrocarbon part of the molecule oriented away from the water. Such details as the depth of immersion of the tail and the configuration of the alkyl group are best approached by considering how the properties of the monolayer depend on the physical variables. 

The Beckmann thermometer used with the bomb calorimeter should be calibrated for the normal depth of immersion with which it is used. To cover the normal range of laboratory temperatures, this calibration should be obtained for three settings of the zero on the scale, convenient values being 10, 15, and 20°C. Such a series of calibrations allows automatically for emergent stem corrections and variations in the value of the degree on the thermometer scale with different quantities of mercury in the bulb, in addition to those arising from inherent variations in the diameter of the capillary bore. 

It should be mentioned that a recent publication (H ) showed that the pitch (frequency) of sound induced by microwave pulses of widths less than 50 ps persisted as the subject s head was lowered into saline water, while the loudness diminished roughly in proportion to the depth of immersion. Upon complete immersion, auditory sensation disappeared. For pulse widths longer than 50 ps, even partial immersion resulted in loss of perception. This was interpreted as being at odds with the thermoelastic theory. There is, however, an explanation that does seem to fit the data. 

Griscom battery — This was a chromic acid (carbon electrode) - zinc - battery with a mechanism to control the depth of immersion of the electrodes in the electrolyte. The latter was attempted to regulate the current for sewing machines. 

In solving problems of enzyme catalysis, molecular biophysics of proteins, biomembranes and molecular biology it is necessary to know the spatial disposition of individual parts. One must also know the depth of immersion of paramagnetic centers in a biological matrix, i.e. the availability of enzyme sites to substrates, distance of electron tunneling between a donor and an acceptor group, position of a spin-label in a membrane and in a protein globule, distribution of the electrostatic field around the PC, etc. 

Distances between unpaired electrons ranging from 5 to 80 A and depth of immersion of a paramagnetic center up to 40 A can be measured by a combination of continuous wave (CW) and pulsed EPR techniques. 

Likhtenshtein, G. I. (2000) Depth of immersion of paramagnatic centers, in Berliner, L, Eaton, S., and Eaton, G. (eds.), Magnetic Resonance in Biology, V. 18, Kluwer Academic Publishers. Dordrecht, pp. 309-347. 

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