Transmission photographs

Figure 5. Transmission photograph of side-wound area.

When monochromatic radiation is used to examine a powder specimen in a Laue (flat-film) camera, the result is often called, for no particularly good reason, a pinhole photograph. (There is no general agreement on the name of this method. Klug and Alexander [G.39], for example, call it the monochromatic-pinhole technique. ) Either a transmission or a back-reflection camera may be used. A typical transmission photograph, made of fine-grained aluminum sheet, is shown in Fig. 6-11. 

Powder specimens may be prepared simply by spreading a bit of the powder mixed with a binder on any convenient support. For a transmission photograph a piece of paper or cellophane will do. If there is any doubt about diffraction from the support material, a control pattern without the specimen can be prepared. 

Figure 6.27 Density variation in a cross section of manganese ferrite powder compact produced by single-action die pressing from the top. High numbers correspond to low density while low numbers correspond to high density. The numbers are the optical density of the x-ray transmission photographs of the compact. (From Ref 31.)...

Transmission electron microscopy (tern) is used to analyze the stmcture of crystals, such as distinguishing between amorphous siUcon dioxide and crystalline quartz. The technique is based on the phenomenon that crystalline materials are ordered arrays that scatter waves coherently. A crystalline material diffracts a beam in such a way that discrete spots can be detected on a photographic plate, whereas an amorphous substrate produces diffuse rings. Tern is also used in an imaging mode to produce images of substrate grain stmctures. Tern requires samples that are very thin (10—50 nm) sections, and is a destmctive as well as time-consuming method of analysis. 

The prediction of drop sizes in liquid-liquid systems is difficult. Most of the studies have used very pure fluids as two of the immiscible liquids, and in industrial practice there almost always are other chemicals that are surface-active to some degree and make the pre-dic tion of absolute drop sizes veiy difficult. In addition, techniques to measure drop sizes in experimental studies have all types of experimental and interpretation variations and difficulties so that many of the equations and correlations in the literature give contradictoiy results under similar conditions. Experimental difficulties include dispersion and coalescence effects, difficulty of measuring ac tual drop size, the effect of visual or photographic studies on where in the tank you can make these obseiwations, and the difficulty of using probes that measure bubble size or bubble area by hght or other sample transmission techniques which are veiy sensitive to the concentration of the dispersed phase and often are used in veiy dilute solutions. 

PAFC systems are commercially available from the ONSI Corporation as 200-kW stationary power sources operating on natural gas. The stack cross sec tion is 1 m- (10.8 ft"). It is about 2.5 m (8.2 ft) tall and rated for a 40,000-h life. It is cooled with water/steam in a closed loop with secondary heat exchangers. The photograph of a unit is shown in Fig. 27-66. These systems are intended for on-site power and heat generation for hospitals, hotels, and small businesses. Another apphcation, however, is as dispersed 5- to 10-MW power plants in metropolitan areas. Such units would be located at elec tric utihty distribution centers, bypassing the high-voltage transmission system. The market entiy price of the system is 3000/kW. As production volumes increase, the price is projec ted to dechne to 1000 to 1500/kW. 

Figure 7.4. Structure of high-density ( 2.0 g/cm ) isotropic pyrolytic carbon, observed by transmission electron microscopy. Viewing plane is parallel to deposition plane (x = 23 600). (Photograph Courtesy J. L. Kaae, General Atomics, San Diego, CA)...

FIGURE 2.8 Transmission electron microscopy (TEM) photographs of clay nanocomposites with acrylonitrile-butadiene rubber (NBR) having (a) 50% and (b) 19% acrylonitrile content, respectively... 

FIGURE 2.13 Transmission electron microscopy (TEM) photographs of (a) FNA4 and (b) F20A4. (From Maiti, M. and Bhowmick, A.K., J. Appl. Polym. Sci., 105, 435, 2007. Courtesy of Wiley InterScience.)... 

FIGURE 3.3 (a) Transmission electron microscopic (TEM) image of acrylic rubber (ACM)-siUca hybrid nanocomposite synthesized from 10 wt% of tetraethoxysilane (TEOS). (From Bandyopadhyay, A., Bhowmick, A.K., and De Sarkar, M., J. Appl. Polym. Sci., 93, 2579, 2004. Courtesy of Wiley Interscience.) Transmission electron microscopic (TEM) photographs of acrylic rubber (ACM)-silica hybrid nanocomposites prepared from (b) 30 wt% and (c) 50 wt% tetraethoxysilane (TEOS) concentrations. (From Bandyopadhyay, A., Bhowmick, A.K., and De Sarkar, M., J. Appl. Polym. Sci., 93, 2579, 2004. Courtesy of Wiley InterScience.)... 

Figure 5. Transmission electron micrographs of Au nanoclusters deposited on the surfaces of the polycrystalline ellipsoidal hematite particles. The left photograph is a close-up view of the right one.

Compression molded (150°C for 3 minutes press chilled with cold water immediately thereafter) samples of poly(trans-l,4-hexadiene) (14) and poly(5-methyl-l,4-hexadiene) were examined with a General Electric (XRD-3) X-ray unit. Transmission Laue X-ray photographs were taken using nickel filtered copper X-radiation. Samples were stretched to four times of their original lengths to obtain oriented fibers. The fiber patterns were obtained in a flat plate film holder with the specimen to film distance standardized at 5 centimeters. X-ray diffraction patterns were similarly obtained for the hydrogenated sample of poly(5-methyl-l,4-hexadiene). 

Figure 5.9 Transmission electron microscopy (TEM) photographs of 3 wt % fluorinated glu-cophospholipid (13) dispersion at room temperature (a) cryo TEM (b) freeze-fracture TEM. Reprinted from Ref. 50 with permission of Academic Press.

Transmission electron microscope photograph of 2-methyl re-sorcinol-PDMSX copolymers using (a) 4400 g/mole PDMSX and (b) 510 g/mole PDMSX. 

Transmission electron microscope photograph of poly (hydroxy-styrene)-PDMSX copolymer. 

Figure 13.17 Photomicrographs of PET filaments showing breaks caused by inclusions. The image shown in (g) was obtained by using transmission illumination, with those shown in (h) and (i) obtained in reflection mode [9], Photographs provided by W. Goltner...

Fig. 2.18 illustrates the nature of the intensity profiles in pure polyetheretherke-tone (PEEK) and carbon fiber reinforced PEEK composites in the transmission and reflection modes, respectively. The quenched amorphous and slowly cooled crystalline components from PEEK can be separated. The three prominent diffraction peaks from the crystalline components in Fig. 2.18(a) correspond to the three uniform rings which can be detected in X-ray photographs. In contrast, no clearly measurable signal is identified from the PEEK amorphous phase independent of the carbon fiber content. 

Luminosity curves for PETN of loading d 1.60 detonated in vacuum are represented nere. The left curve was photographed, using optical filters, with transmission maxima at A=6870, while for the right one A was 4510. In this type of curve, the intensities of the peaks with maximum deflection during the deton interval were used for the evaluation of temperature of detonation... 

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