Elemental dot-mapping

FIGURE 8.2 Backscattered electron image of surface soil and corresponding x-ray elemental dot maps. White colors indicate highest concentration of target elements, and dark spots indicate low concentration. 

Figure 2. Elemental dot map of Paracas hair fiber indicating distribution of sulfur (left) and potassium (right).

Figure 6. Elemental dot map of bast fiber, Etowah Mound C 1145 core, indicating distribution of iron (left) and copper (right).

Figure 7.22. Elemental dot-maps. Shown is (a) elemental concentrations of Si, O, and F (as white pixels) overlaid onto the SEM image of a Nafion resin/sihca composite[33l (b) bright-held STEM image of a GaN/AlN/AlGaN nanowire cross section, with elemental mapping of Ga, N, and A1 (scale bar is 50nm).[34l...

SEM-EDX data (Melamed et al., 2003) detected the presence of pyromorphite at the 0 to 10-cm soil depth of T3 treatment and the association of Pb with P. The elemental dot map also showed the association of Ca with P, coherent with addition of PR. Even at the 30 to 40-cm soil layer of T3 treatment, the EDX revealed the presence of pyromorphyte after 217 days of P application. 

In particular, it is possible to overlay the image with the EDS data - a technique known as elemental dot-mapping, widely used for SEM/EDS analysis (Figure 7.20). 

There are three modes of analysis commonly used spectrum acquisition spatial distribution, or dot, mapping of the elements and elemental line scans. 

Often, more detailed information is needed on the distribution of a constituent. The technique of X-ray area scanning, or dot mappings can provide a qualirative view of elemental distributions. As the beam is scanned in a raster pattern on the specimen, a cathode ray rube scanned in synchronism is used to display a full white dot whenever the X-ray detector (WDS or EDS) detects an X ray within a certain narrow energy range. The pattern of dots is recorded on film to produce the dot map. Dot maps are subject to the following limitations ... 

Figure 5. Scanning-electron microscope (SEM) images of pyrite within a dolomite host rock. Sample is from borehole S-35 (see Fig. 3 for location). A fifty micrometer scale bar is shown for reference. The uppermost panel is a backscattered electron image. The bright area is pyrite and the dull areas are dolomite. The remaining 4 images are dot maps showing the relative abundance of specific elements. The brighter the image, the higher is the relative abundance of the element. Note the correlation of arsenic (As) with pyrite as indicated by the Fe and S dot maps, and the anticorrelation with dolomite (Ca dot map).

Figure 18. Mapping of experimental time-of-arrival data for mass 27 (HCN) to volume elements in the charge. The experimental data (the series of rectangular bars) in arbitrary units, the calculated total fluid density in g/cm (sawtooth curve), and the mapping of time intervals back to volume elements (dotted lines) are shown. This calculation is an earlier one that started with somewhat less realistic conditions than those used in the most recent calculations.

Fig. 11.8. The valence map of a (110) section through Cap2 showing possible locations for ions. The 1.0 vu contour is shown with a dot and dash line. Contours less than 1.0 vu are shown with a broken line, those larger than 1.0 vu with a solid line. The contour interval is 0.2 vu. Contours above 1.8 vu have been omitted for clarity. Atomic positions are shown by the element s3Tubol (one F has been omitted to show the contours at this site). X, Y, and Y are proposed sites for an interstitial F ion as discussed in the text.

The results of PCA and FA are usually discussed in terms of scores and loadings. Scores represent the incidence of a selected association of elements, expressed as a dimensionless value, at each sampled site, and can be mapped using dot or interpolated maps. 

Risk maps do not need any peculiar mapping technique to be produced, but are based on the reclassification of geochemical data, represented as dots or interpolated, by means of TAL established by law for each element of concern. The main aim of a risk map is to highlight zones of urban areas that are in excess of TAL values and hence require potential remediation. It should be noted, however, that background values (unaffected by anthropogenic input) may exceed TAL values in some circumstances. 

Figure 4. (A) Electron micrograph of fracture surface from an x = 0.1S8 pellet produced by composite method. The distance between the black dots on the white bar corresponds to 10 /im. (B) X-ray fluorescence map of bismuth for the same region as in (A). White points indicate th presence of detected element. Continued on next page.

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