Photographic technique

Gal-Or and Resnick (Gl) have developed a simplified theoretical model for the calculation of mass-transfer rates for a sparingly soluble gas in an agtitated gas-liquid contactor. The model is based on the average gas residencetime, and its use requires, among other things, knowledge of bubble diameter. In a related study (G2) a photographic technique for the determination of bubble flow patterns and of the relative velocity between bubbles and liquid is described. 

These derivations have been described in detail (15). However, the relationship in Equation 5 was found to be very unsuitable for the determination of yij, since the curvatures are not easily evaluated from the photographic images. Especially, the older studies were unsatisfactory, arising from the inadequate optical and photographic techniques. In a later analysis an empirical procedure was described (21) which defined a function, S, which determines the drop shape as ... 

Kintner et al (K7) and Damon et al. (Dl) have discussed photographic techniques applicable to the study of bubbles and drops. Sometimes it is desirable to hold a bubble or drop stationary, to study internal or external flow patterns and transfer processes. To prevent the particle from migrating to the wall, it is desirable to establish a minimum in the velocity profile at the position where the particle is to reside, and various techniques have been devised (D4, FI, Gl, Pll, M15, R15, S20) to do this. Vertical wandering of such particles may occur (W7), and may be reduced by using a duct tapered so that the area decreases towards the top (D4). Acoustic levitation of liquid drops may also be used (A3). 

Williams, M. D., E. Treiman, and M. Wecksung, Plume Blight Visibility Modeling with a Simulated Photograph Technique, J. Air Pollut. Control Assoc., 30, 131-134 (1980). 

With the qualitative illustration of observable shock and bubble parameters shown in Fig 5, we can now proceed to a description of the test methods used to obtain such data. Figs 2 5 immediately suggest the use of pressure transducers to follow the pressure-time histories of underwater explns. Similarly Fig 1 (bottom portion) suggests the use of visual (photographic) techniques to obtain dimensions and positions of the gas bubbles. Indeed, these are the major techniques now used in studying underwater shock and bubble effects... 

G.D.Kahl F.D.Bennett, Ibid, 763 7(Mach-Zehnder interferometer) ff)M.Lorant, Functional Photog 5, 4-6(March 1954)(New photographic techniques in HE research) gg)M.Sultanoff R.L.Jameson, JSocMotPictTelevEngrs 69, 113-15(l960)(New observations of expl phenomena by submicrosecond color photography)... 

Akita and Yoshida (1974) determined the bubble-size distribution in bubble columns using a photographic technique. The gas was sparged through perforated plates and single orifices, while various liquids were used. The following correlation was proposed for the Sauter-mean diameter ... 

The same data collection and reduction techniques are commonly used by the same workers for many different polymers. Therefore, data for these other polymers may contain errors on a similar scale, but that the errors have usually, but not always, gone undetected (8). If more than 500 reflections are observed, from single crystals of simple molecules, recognizable electron-density distributions have been derived from visually estimated data classified only a "weak", "medium" or "strong". The calculation of the structure becomes more sensitive to the accuracy of the intensity data as the number of data points approaches the number of variables in the structure. One problem encountered in crystal structure analyses of fibrous polymers is that of a very limited number of reflections (low data to parameter ratio). In addition, fibrous polymers usually scatter x-rays too weakly to be accurately measured by ionization or scintillation counter techniques. Therefore, the need for a critical study of the photographic techniques of obtaining accurate diffraction intensities is paramount. 

High-speed photographic techniques have shown that during the discharge process some smoke emerges from the muzzle ahead of the bullet and also that just after the bullet leaves the muzzle it is surrounded by a large cloud of smoke over a short distance.111... 

In time the Brady Co. wanted to buy Dylux solutions and coat them on an adhesive-backed film. They had designed a small optical printer, which involved different fonts and logos produced by a photographic technique, through which one would expose the photosensitive-coated material with a flash of light. We sent them some samples, but warned Brady that the decision to sell such materials had not been made. DuPont was reluctant to sell the chemical mix to anyone for fear that they would compete with us and make their own, competitive, proof paper. 

Each ponderosa pine 4.00 inches dbh or larger was examined and assigned a value to describe the degree of oxidant injury. This score system for pine was a slight modification of a method used previously with aerial photographic techniques to detect and evaluate oxidant injury (4) ... 

The photographic technique for bubble size usually gives just local values. It does not take into account large bubbles and is applicable only for small gas holdup (i.e., at a low gas velocity). Several measurements in different zones of the vessel are generally needed. 

The correct interpretation of an air photo depends not only on the expertise of the interpreter, but also on the resolution of the photo and on the sharpness of its focus, in other words, on the quality of the cameras, films and the photographing technique (e.g., compensation for the motion of the airplane). The technique of stereoscopy in particular has effected great improvements in air photo interpretation. In this technique, two photos of the same area are taken in rapid succession. Due to the motion of the airplane, the angle at which the photos are taken will have changed somewhat in this brief time. If these two slightly different photos are then viewed through a stereoscope, one picture with each eye, the result is a three-dimensional effect that allows for the easy differentiation between raised and flat objects on the ground.1... 

Because the amplitude of the lattice distortion in the Peierls insulator is very small, the X-ray scattering associated with it is weak. Furthermore the one-dimensional nature of this distortion gives rise to diffuse Bragg planes instead of the usual well-defined Bragg reflections. These two facts have led to the development of a special diffuse X-ray photographic technique often referred to as the monochromatic Laue technique or XDS (for X-ray diffuse scattering) (64). 

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