Instrumental analyses of modified

Continuous scans of modulus versus temperature utilizing the DuPont Dynamic Mechanical Analyzer (DMA) has provided a comparison of the high temperature service capabilities of radiation-cured experimental formulations of a vinyl-modified epoxy resin. Shell Epocryl-12. These scans were compared to data obtained when the same materials were applied as adhesives on aluminum test panels, radiation-cured with an electron beam, and lap shear strength tested at discrete temperatures. The DMA instrument utilizes a thin rectangular specimen for the analysis, so specimens can be cut from blocks or from flat sheets. In this case the specimens were cured as sheets of resin-saturated graphite-fibers. The same order of high temperature stability was obtained by each method. However, the DMA method provided a more complete characterization of temperature performance in a much shorter test time and thus, it can be very useful for quick analyses of formulation and processing variables in many types of materials optimization studies. The paper will present details of this study with illustrations of the comparisons. 

In this protocol, direct surface analyses using IT-SIMS will be described from the perspective of analyses that were conducted to measure chemical warfare agents and related compounds (precursors, degradation products, and surrogates) that were adsorbed on samples from exposed environments. During the course of the research that is described in this chapter, the basic instrumental design of the IT-SIMS was modified for the analysis of absorbed compounds, and so the utilization of the instrument for these purposes is also described. 

Both direct and indirect methods are used in studying soil chemistry. While in all cases direct methods are preferable, it is not always possible to make direct observations of all the chemical species, and physical and chemical changes of interest. Thus, it is often necessary to modify the soil before analysis. In many cases, it is essential to extract components before analysis can be carried out. It is also possible to obtain valuable information about the chemistry of soil by carrying out analyses that destroy all or a part of the soil matrix. A summary of analysis types and instruments commonly used in soil analysis is given in Table 8.1. 

A recent brief review showed the working principles of various automatic analyzers6. A modified account of N and O analysis will be presented here. Today there exist in the market instruments that perform organic elemental analyses in a few minutes. The ease and speed of such analyses enable the use of such instruments for routine analysis. Although some operational details vary from model to model and between one manufacturer and another, all these instruments can be considered as exalted versions of the classical Pregl determination of C and H by conversion to CO2 and H2O, together with Dumas method for N by conversion to N2, the calorimetric bomb method for S by conversion to SO2 and SO3 and Schultzes method for O by conversion to CO. This is combined with modern electronic control, effective catalysts and instrumental measuring methods such as IR detectors and GC analyzers. 

For both qualitative and quantitative elemental analyses using EDS detectors in an AEM it is essential that the analyst understands the limitations of a particular experimental configuration and that a consistent protocol which optimises all analyses in a given experiment is employed. There is such a variety of instrument and detector configurations currently in use that only a brief summary of important considerations for modern-day AEMs will be addressed here. In older TEMs which have been modified for quantitative thin-film analysis [23], instrument dependent parameters should be critically assessed before attempts are made to quantify X-ray spectra. 

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