Effect of Sample Treatment

The effect of heat treatment on structure, fracture strength and chain scission has been very extensively investigated by Statton, Park and DeVries [25-27] and by Lloyd [5]. With respect to our understanding of chain breakages in annealed fibers the following morphological changes seem to be particularly noteworthy. Relaxed heat treatments result in [25]  

Increases of the degree of crystallinity, perfection of crystallites, density, chain folding. Young s modulus, and intensity of the fluid-like component of the NMR-signal. 

Decreases of sample length (shrinkage), breaking strength, sonic modulus, and Tg. 

The changes are the more intense the higher the annealing temperature. Tension during annealing tends to modify or reduce the above listed effects. Relaxed and tension annealing do, however, increase the long period. 

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Koch, P.L., Tuioss, N. and Fogel, M.L. 1997 The effects of sample treatment and diagenesis on the isotopic integrity of carbonate in hiogenic hydroxylapatite. Journal of Archaeological Science 24 417--t29. 

FIGURE 4.6 Electrochemical lithiation/delithiation of SWNT electrodes effect of sample treatment on potential profile. Top purified SWNT. Middle SWNT ball milled for 1 min. Bottom SWNT ball milled for 10 min. The data were collected at a constant current of 50 mA/g. Reprinted from Ref. [133]. Copyright 2000, with permission from Elsevier. 

Wibetoe, G., Takuwa, D. T., Lund, W. D. and Sawula, G. Coulter particle analysis used for studying the effect of sample treatment in slurry sampling electrothermal atomic absorption spectrometry. Fresenius J. Anal. Chem. 363 46, 1999. 

Figure 2 Effect of pre-treatment on TPR of lRelPt(e,calc.) catalyst. Sample...

Sample preparation. All allantoic fluid of chicken embryos or calf serum used in experiments contained influenza virus (104—106 EID50/ml). The samples of biological fluids underwent photodynamic treatment as described above. One milliliter aliquots were taken before treatment and at 3 and 6 h after the start of experiment. To analyze the effect of photodynamic treatment on proteins we used alkaline denaturing electrophoresis in the presence of sodium dodecylsulfate (SDS) and P-mercaptoethanol (P-ME). 

One final test was conducted on a heat treated sample to elucidate the effect of heat treatment and sensitization on the fracture behavior of this steel. A CF sample was heated for 24 hours at 650°C to see if the fracture mode would continue to change with an even larger amount of carbide precipitation. Note in Figure 15-a this heavily sensitized steel has a fracture appearance that is completely dominated by small microvoids associated with carbides. The bimodal distribution of microvoids like those in Figure 7 has been eliminated. In fact, the fracture appearance is remarkably similar to that of the tritium-exposed-and-aged steels albeit at a different magnification (Figure 15-b). It appears that carbides in the microstructure affect the fracture mode in a similar manner as the decay helium bubbles but on a different scale. 

Most of the work with alumina was done, however, attempting to elucidate the nature of the catalytically active sites in dehydrated alumina. The catalytic activity of alumina is enhanced by treatment with hydrofluoric acid. Oblad et al. (319) measured a higher activity in the isomerization of 1- and 2-pentene. Webb (339) studied the effect of HF treatment on ammonia adsorption by alumina. There was no difference in the capacity. However, the ammonia was more easily desorbed at a given temperature from the untreated sample. Apparently, the adsorption sites grew more strongly acidic by the treatment. No NH4+ ions, only NHj molecules were detected by their infrared spectra, indicating that the ammonia was bound by Lewis acids rather than Bronsted acids. 

It is suggested that a detailed examination of the effect of heat-treatment temperature on the gas reactivity of the carbons studied by Walker and Baumbach 143) might show a series of reactivity maxima which correspond to temperatures at which different catalytic impurities first begin to show significant solid state diffusion and reaction with the carbon matrix followed at higher temperatures by their complete volatilization from the sample. The advent of significant diffusion and reaction of the impurity with the carbon could result in a subseiiuent increase in gas reactivity. Complete volatilization of the impurity from the sample could result in a subsequent decrease in gas reactivity. 

Figure 7. Effects of AgNOs treatment on ion current profile of GAC filter effluent. IS — internal standard. Peaks labeled in untreated sample were removed or reduced by AgNO3. Peaks labeled in AgNC>3-treated sample were created or increased by the treatment.

Figure 4. Effect of hydrothermal treatment in boiling water on isotherms and pore size distribution of the calcined samples A and B.

The oil stability index (OSI) method provides results in a matter of hours instead of months (required for studies done at ambient temperatures). These OSI results are useful as comparative measures of oxidative stability, i.e., to determine the effect of a treatment or antioxidant compared to a control sample. Meaningful predictions of the actual shelf lives of specific commodities require that such shelf life studies be performed at ambient conditions. If only accelerated tests are to be performed, two or more tests based on different principles of lipid oxidation measurement should be conducted the effect of accelerated storage temperature should also be investigated. 

Control experiments were made to ascertain that the increase in dispersion stability in the presence of carbcxylated block copolymer was indeed caused by adsorbed block copolymer and was not a side effect of the treatment—e.g., the result of a breakdown of the titanium dioxide particles from severe agitation or the result of factors associated with the exposure of the samples to elevated temperatures. Titanium dioxide was heated and agitated in o-dichlorobenzene under the same conditions as the samples listed in Table I but without block copolymer. After the agitation stopped, all particles, including the fraction of very small par-... 

The coarseness of a surface and consequently the effect of surface treatment can be measured with a laser beam. In addition the surface is often investigated by means of various microscopic techniques. The nature of a surface can tell us something of the structure of the material. The information obtained depends on the treatment the area has undergone and the way in which the surface is examined. The researcher may want to determine how many phases there are present in the sample, how they are distributed throughout the sample or what the pores and the pores distribution are like. For these purposes many kinds of light and electron micros-copes are available. 

Moreover, the isotopic heteroexchange of oxygen is a very sensitive photoassisted gas-solid reaction. For example, it is much more affected by the texture (33) or by the doping (35) of Ti02 samples than the oxidation of different organic compounds in gas (33, 35), liquid or aqueous solutions (35). It can therefore be used to evaluate more precisely the effect of various treatments. 

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