An analysis of the possible causes of apparent compensation effects when investigating a substance under varying experimental conditions

The major causes leading to the apparent compensation effect (lgA=aE+b) at the thermal decomposition of one and the same substance in a series of experimental conditions (varying of the mass of the sample, of the heating rate, of disperseness, and at different distances from the equilibrium) were discussed. It was found that the appearance of a compensation effect at the study of the thermal decomposition of one and the same substance demonstrates the incorrect setup of the experiment, resulting in erroneous values calculated for the kinetic parameters.

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Zusammenfassung Die Hauptursachen, welche zum scheinbaren Kompensationseffekt (lgA=aE+b) der thermischen Zersetzung ein und derselben Substanz führen, wurden unter verschiedenen Versuchsbedingungen untersucht: unter Änderung der Probenmasse, der Aufheizgeschwindigkeit, der Dispersität und der Entfernung vom Gleichgewicht. Es wurde festgestellt, daß das Auftreten eines Kompensationseffekts bei der Untersuchung der thermischen Zersetzung ein und derselben Substanz auf die unrichtige Durchführung des Experiments hinweist, die zur Berechnung falscher Werte der kinetischen Parameter führt.

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Résumé On a étudié les causes principales de l'effet de compensation apparent (lgA=aE+ +b) lors de la décomposition thermique de la même substance dans différentes conditions expérimentales, en faisant varier notamment la masse du prélèvement, la vitesse du chauffage, la dispersion et l'écart à l'équilibre. On a trouvé que l'apparition d'un effet de compensation lors de l'étude de la décomposition thermique de la même substance résultait de l'exécution incorrecte de l'expérience qui mène à des valeurs fausses lors du calcul des paramètres cinétiques.

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, (lg A=aE+b) : , , , . , , .

     

Stabilization of reaction products of ureas with polyfluoro ketones

Conclusions Polyfluorinated tetrahydro-1,3,5-oxadiazine derivatives were obtained by the condensation of urea and thiourea with polyfluoro ketones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2168–2169, September, 1977.     

Accurate fast neutron activation analysis for oxygen in geological materials

Sources of error in the fast neutron activation analysis determination of oxygen have been investigated and minimised. The oxygen contents of eighteen international rock standards and a sulphide ore standard have been determined, and compared with the values calculated by difference using the reported full analyses. Accuracies of 0.3% average deviation and reproducibilities of ±0.2% standard deviation have been obtained, where oxygen contents exceeded 1.0 g.     

THE SYNERGISTIC ACTION OF ULTRAVIOLET AND X RADIATION ON MUTANTS OF ESCHERICHIA COLI K-12

Abstract— Prior UV irradiation increased the X-ray sensitivity of wild-type E. coli K-12. This synergistic effect of combined UV and X irradiation was also observed, but to a reduced extent, in uvrA, uvrB, uvrC , and polA mutants, but was absent in exrA, recA, recB , or recC mutants of E. coli K-12. Alkaline sucrose gradient studies demonstrated that the wand err gene-controlled, growth-medium-dependent (Type III) repair of X-ray-induced DNA single-strand breaks was inhibited by prior UV irradiation. This inhibition probably explains the synergistic effect of these two radiations on survival.     

The role of electronic factors in reagents in controlling thestereochemistry of arylsulfenyl chlorides addition

For a series of substituted arylsulfenyl chlorides the stereochemistry of Ad_E-reactions with a series of substituted Z- and E-β-deuterostyrenes has been elucidated. Non-stereospecific reaction was observed only for the pair 2,4-dinitrobenzenesulfenyl chloride-p-methoxystyrene; for all the other reactants the reaction proceeded in a strictly stereospecific manner.     

Investigation of the reduction of methylenequinones by methods of polarography and EPR spectroscopy

Conclusions The polarographic reduction of certain methylenequinones was studied, and the mechanism of the reduction was investigated by the method of EPR spectroscopy.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1656–1658, July, 1970.     

EPR spectra of halogenonitromethane anion radicals

Conclusions It was deduced that fluorine is in a -combined state in the anion radicals we studied; this was based on an analysis of the EPR spectra of a series of fluoronitroalkane anion radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 458–460, February, 1969.In conclusion, the authors express their appreciation to A. A. Fainzil'berg for his interest in our work.