Experimental design External standards

O.IM bile salt (Xi = 0) and an equimolar lecithin to bile salt ratio X = 0). Also each distinct experiment was done twice. These replications, which are complete and carried out under identical experimental conditions, allow us to estimate the repeatability, without any external influence, and thus to have a good idea of the dispersion of the results and the extent of the experimental error. The 10 experiments are carried out in random order. The experiment design, plan, and the response data are all listed in table 4.2 in the standard order. 

To return now to practical measurements of heat of reaction, it is djvious that for experimental determination, one need only enclose the reactants in a calorimetric bomb, initiate the reaction, and measure (as described briefly above) the amount of heat released. One complication is that for a rather inert system, the customary electrically heated wire loop, which requires only a trifling correction, must be enhanced by a first fire mixture, thus reducing precision even if corrections are applied. Some mixtures may be entirely unreactive in the small amounts accommodated in the standard calorimeters. Undoubtedly, everyone concerned with these problems has had some ideas on designing a 55 gallon drum type calorimeter with or without admission of external air, but the author is not aware of any pub-Nshed experimentation along these lines. 

IR spectroelectrochemistry has been the subject of a sizeable amount of early reviews, where the experimental details and applications have been described [5-7]. Regardless the fact that electrochemistry is an extremely broad field, the following discussion will be restricted to classical electrochemical systems where a solid electrode is in contact with a liquid electrolyte solution which may contain electroactive species. Since the typically used electrolyte solutions (mostly aqueous solutions) are strongly IR absorbing, it is not possible to use a standard laboratory electrochemical cell, but for spectroelectrochemical experiments, special cell designs and beam paths have to be employed. There are two general principles on how the IR beam is directed to the electrode surface called internal reflection and external reflection, respectively. 

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