Studium der Alterung von Naturkautschuk mittels Infrarotspektroskopie V. Wärmebeschleunigte Alterung

Kellö, V.; Tkáč, A.; Hrivíková, J.

doi:10.1135/cccc19560281

Cited by 3 publications

(4 citation statements)

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“…From these equations we can express dn i /dt. Comparing the relations obtained we get r (7) (T ) = c ik V r (10) (T ) r (8) (T ) = c ik r (10) (T ) r (9) (T ) = V r (10) (T ) r (11) (T ) = c ik r (10)…”

Section: Rate Of Reactionmentioning

confidence: 83%

“…and thus we have r k (T ) = r (10) k (T ). The rate of reaction defined by relation ( 10) is in keeping with the mass action law; its value depends on neither the volume of system nor the species by means of which it is expressed, but it is not quite in keeping with the recommendation of the International Union of Pure and Applied Chemistry, which, as reported by Kellö and Tkáč in [9], recommends the rate of reaction as defined by relation (9). In [16] Atkins refers to the rate w (9) k as the 'true rate'.…”

Section: Rate Of Reactionmentioning

confidence: 98%

“…According to the mass action law the rate constant r (d) k is a function of T alone and does not depend on composition. If r (10) k = r (10) k (T ), then from the last five relations it follows that r (8) k only depends on T while r (7) k , r (9) k , r (11) k and r (12) k are functions of T alone only for processes where the volume V of system S is constant. The assumption of V remaining constant is, however, not given in the respective literature.…”

Section: Rate Of Reactionmentioning

confidence: 99%

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On kinetics of reactions in HV circuit breakers after current zero

Adamec¹,

Coufal²

1999

J. Phys. D: Appl. Phys.

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An analysis of six different definitions of the rate of reaction is made and it is shown that some of the definitions are not consistent with the mass action law. Kinetic equations are derived whose solution is the time dependence of the composition of an arbitrary closed gaseous system in an ideal state for a given time dependence of temperature on the assumption that either the time dependence of pressure in or the time dependence of the volume of is given. Results are given of the computation of composition of a system of SF6 dissociation and ionization products at a temperature drop from 12 000 K to room temperature and a comparison is made of the time-dependent composition with equilibrium composition for pressures of 0.1, 0.5, 1 and 2 MPa.

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Section: Rate Of Reactionmentioning

confidence: 83%

Section: Rate Of Reactionmentioning

confidence: 98%

Section: Rate Of Reactionmentioning

confidence: 99%

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On kinetics of reactions in HV circuit breakers after current zero

Adamec¹,

Coufal²

1999

J. Phys. D: Appl. Phys.

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“…However, no substantial change of Conclusions derived from our Table IV is to be expected. Full account of investigation of the reaction $F2+ $H2 = HF, including the fourth-order calculation of vibrational corrections and calculations of the equilibrium constant, will be published elsewhere [59].…”

Section: This Expression Leads To the Energiesmentioning

confidence: 99%

Fourth‐order diagrammatic MB–RSPT calculations of the correlation energy: N₂, CO, F₂ and the reaction energy of the process ½F₂ + ½H₂ = HF

Kellö

Urban

1980

Int J of Quantum Chemistry

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AbstractsThe correlation energies obtained by the fourth-order diagrammatic perturbation theory were analyzed for three diatomic molecules: N2, CO, and F2. The results were compared with correlation energies obtained previously for the ten-electron hydrides HF, H 2 0 , and NH3. The relative importance of contributions which arise from the double excitations, from the quadruple excitations, as well as from the renormalization term was investigated. It is shown that for the diatomic molecules under study these contributions are considerably larger than for the ten-electron hydrides not only in absolute value but also in percentage: they represent about 3 , 3 , and 5%, respectively, of the valence shell correlation energy obtained by the perturbation theory up to the fourth order. A careful analysis of the fourth-order correlation effects is also presented for the reaction energy of the process i H z + $FZ = HF.Les energies de correlation obtenues par la thkorie des perturbations diagrammatique du quatrieme ordre ont Ctt analystes pour trois molecules diatomiques: Nz, CO, et Fz. Ler resultats ont e t t compares avec des Cnergies de corrtlation obtenues prtctdemment pour les hydrures ? i dix electrons: HF, H20, et NH3. L'importance relative des contributions dues aux excitations doubles et quadruples ainsi que de celles provenant du terme de renormalisation a &te examinee. I1 est dCmontrC que pour les molecules diatomiques en question ces contributions sont considtrablement plus importantes que pour les hydrures, en valeurs absolues mais aussi en pourcentage: elles reprtsentent environ 3, 3, et 5 % , respectivement, de I'bnergie de correlation de la couche de valence, obtenue par la thtorie des perturbations jusqu'au q u a t r i h e ordre. Une analyse dttaillde des effets de correlation du quatribme ordre est prCsent&e aussi pour I'Cnergie de rCaction du processus 2H2 + iF2 = HF.Die mit diagrammatischer Storungstheorie vierter Ordnung erhaltenen Korrelationsenergien sind fur drei zweiatomige Molekule, N2, CO, und Ez, analysiert worden. Die Resultate sind mit fruher erhaltenen Korrelationsenergien fur die Zehnelektronenhydriden HF, H 2 0 , und NH3 verglichen worden. Die relative Bedeutung der von Doppel-und Quadruppelanregungen als auch der vom Renormierungsglied herruhrenden Beitrage ist untersucht worden. Es wird gezeigt, dass fur die hier studierten zweiatomigen Molekule diese Beitrage betrachtlich grosser als fur die Hydriden, nicht nur absoluterweise aber auch in Prozent, sind. Sie stellen ungefahr 3, 3, und 5%, bzw., der mit Storungstheorie vierter Ordnung erhaltenen Korrelationsenergie der Valenzschale dar. Eine sorgfaltige Analyse der Korrelationseffekte vierter Ordnung wird auch fur die Reaktionsenergie des Prozesses $ H~ + f~, = HF prasentiert. KELLO AND URBANnumerical tractability. In both these respects the diagrammatic many-body Rayleigh-Schrodinger perturbation theory (MB-RSPT) represents a very appealing method. Already at its simplest level represented by the second and third order, this method provide...

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Über zusammenhange zwischen dem vernetzungsgrad und der degradation von naturkautschuk

Tkáč

Kellö

1958

J. Polym. Sci.

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Oxidation reactions, as followed by infrared spectrometry, may serve as a measure for judging the relative extent of oxidative degradation and crosslinking of two independent parallel reactions subsequent upon the primary destruction. Such information can be derived from a kinetic analysis of the processes taking place in the rubber as a result of the absorption of energy, using the expression w = (k/b) (1 − e−bη) (1 − η). Since in this equation k is proportional to the rate of chain branching (which leads predominantly to oxidation), and b is proportional to the rate of recombination of the radicals (leading to crosslinking), the total degree of crosslinking will increase with increasing values of b/k. This assumption has been verified experimentally for the thermal and photochemical ageing of rubber, both in the absence of additives and in the presence of sulfur, of vulcanizing mixtures, and of copper as a catalyst of oxidation. At increased temperatures and pressures (130°C., 3 atm.) in the absence of vulcanizing additives and in a nitrogen atmosphere, radicals of long life are formed; this leads to an increased rate of the subsequent oxidative degradation. The number of active centers formed, and hence the final extent of oxidation, is a function of the time of exposure to the increased temperature.

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Studium der Alterung von Naturkautschuk mittels Infrarotspektroskopie V. Wärmebeschleunigte Alterung

Cited by 3 publications

References 0 publications

On kinetics of reactions in HV circuit breakers after current zero

On kinetics of reactions in HV circuit breakers after current zero

Fourth‐order diagrammatic MB–RSPT calculations of the correlation energy: N₂, CO, F₂ and the reaction energy of the process ½F₂ + ½H₂ = HF

Über zusammenhange zwischen dem vernetzungsgrad und der degradation von naturkautschuk

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Studium der Alterung von Naturkautschuk mittels Infrarotspektroskopie V. Wärmebeschleunigte Alterung

Cited by 3 publications

References 0 publications

On kinetics of reactions in HV circuit breakers after current zero

On kinetics of reactions in HV circuit breakers after current zero

Fourth‐order diagrammatic MB–RSPT calculations of the correlation energy: N2, CO, F2 and the reaction energy of the process ½F2 + ½H2 = HF

Über zusammenhange zwischen dem vernetzungsgrad und der degradation von naturkautschuk

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Fourth‐order diagrammatic MB–RSPT calculations of the correlation energy: N₂, CO, F₂ and the reaction energy of the process ½F₂ + ½H₂ = HF