Experimental procedure temperature effect

It is commendable experimental procedure to repeat each run in duplicate and to be satisfied if the two results agree, but this is expensive in terms of the labor costs involved. Moreover, repetition of each run is not always necessary. For example, if one is studying the effect on the reaction rate of a variable such as temperature or reactant concentration, a series of experiments in which the parameter under investigation is systematically varied may be planned. If a plot of the results versus this parameter yields a smooth curve, one generally assumes that the reproducibility of the data is satisfactory. 

How this smoke effect varies with inert addition is best explained by considering the results of many early investigators who reported that incipient soot formation occurred in a very narrow temperature range. The various results are shown in Table 8.6. Since, as stated earlier, the incipient particle formation mechanisms for various fuels follow quite similar routes, it seems appropriate to conclude that a high activation energy process or processes control the incipient particle formation. The best concept and evidence to date is that given by Dobbins [77], It is likely that the slight variation of temperatures shown in Table 8.6 is attributable to the different experimental procedures... 

Fig. 1 Effects of forced swimming (15 min, water temperature 25 °C) on hippocampal extracellular levels of 5-HT (expressed as percentage of baseline) in male Wistar rats as assessed by in vivo microdialysis. Extracellular levels of 5-HT showed a dramatic increase in rats that dived diming the forced swimming procedure. This effect could be prevented by i.c.v. pretreatment of the rats with the CRH receptor antagonist o-Phe-CRH 12-41 (5 pg)., p<0.05 as compared to non-divingsaline-pretreated rats , p<0.05 as compared to diving d-Phe-CRHi2-4i -treated rats (Scheffe post-hoc comparisons). For experimental details, please see text and original paper. (From Linthorst et al. 2002, with permission of European Journal of Neuroscience)...

Effect of the dispersed phase on the apparent viscosity-temperature curve. Maxima do not always appear in the apparent viscosity-temperature curves. A recent report (25) shows that the appearance of the maximum in the D - HTT curve could be an artifact produced by experimental procedure. Whilst this is undoubtedly the case in some systems, whether it is always the case is not yet clear. At this stage it will suffice to review factors that may be important in determining the form of these 11 in-situ1 results. 

These points respectively define the temperature at which, on reheating, a cooled or quenched pyrolysis residue begins to soften and develop fluidity and the temperature at which the liquid residue begins to change its chemical composition, i.e., when pyrolysis recommences. This latter point is more ambiguous since it is determined from a thermogravimetric experiment which is subject to the effects of experimental procedure, as discussed earlier. Therefore, it is essential to use a fixed heating rate, etc., in the determination of the decomposition temperature. The volatile content can be determined in the same experiment. 

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