An analytical method for determining rate constants using a periodical irradiation technique

1969 ◽  
Vol 47 (24) ◽  
pp. 4531-4535 ◽  
Author(s):  
W. Kawakami ◽  
H. S. Isbin
Keyword(s):  
Rate Constants ◽  
Analytical Method ◽  
Apparent Rate Constant ◽  
Chloral Hydrate ◽  
Life Time ◽  
First Order ◽  
Radical Concentration ◽  
Γ Rays ◽  
The Mean

A new analytical method is presented for the determination of rate constants using a periodical irradiation technique. This method is applicable to reactions which have both a first and a second order termination for the chain radical concentration, and is illustrated for the radiolysis of aqueous solutions of chloral hydrate by 137Cs γ rays. The apparent rate constant of first order termination, and the mean chain life time of the chain radical were determined to be 1.10 s−1, and 0.25 s for 400 rad/min, at 22 °C, respectively.

Kinetics of the Ozonation of Tetrabromobisphenol-A in Wastewater

2011 ◽  
Vol 383-390 ◽  
pp. 2945-2950 ◽  
Author(s):  
Jie Zhang ◽  
Shi Long He ◽  
Mei Feng Hou ◽  
Li Ping Wang ◽  
Li Jiang Tian
Keyword(s):  
Rate Constants ◽  
Apparent Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Kinetic Studies ◽  
Tetrabromobisphenol A ◽  
First Order ◽  
Reaction Rate Constants ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of TBBPA degradation by ozonation in semi-batch reactor was studied. The reaction rate constants of TBBPA with O3 and •OH were measured by means of direct ozone attack and competition kinetics, and the values of which were 6.10 l/(mol•s), 4.8×109 l/(mol•s), respectively. Results of kinetic studies showed that TBBPA degradation by ozonation under the different conditions tested followed the pseudo-first-order. The values of apparent rate constant of TBBPA degradation increased with the increase of ozone dosage and pH, but decreased with the increase of initial TBBPA concentration.

Microstructure Evaluation for Time Dependent Nucleation Protocols in KJMA Kinetics

1999 ◽  
Vol 580 ◽  
Author(s):  
Eloi Pineda ◽  
Daniel Crespo
Keyword(s):  
Mean Field ◽  
Quantitative Agreement ◽  
Nucleation And Growth ◽  
Time Dependent ◽  
First Order ◽  
Microstructure Evaluation ◽  
The Mean ◽  
Dependent Growth ◽  
First Order Phase

AbstractThe microstructure developed in a first order phase transformation is obtained using a populational extension of the Kolmogorov, Johnson-Mehl and Avrami (KJMA) model, PKJMA. PKJMA allows one to determine the grain size distribution resulting from nucleation and growth kinetics. PKJMA is grounded on the mean field hypothesis that the free space around the growing grains is randomly distributed, independent of the grain radius. Although this approach is perfectly valid for the case of constant nucleation, a detailed analysis of the model shows that this hypothesis does not hold in the case of time dependent nucleation protocols or pre-existing nuclei. In this work, the PKJMA model has been improved by estimating the average free surface around the grains as a function of their radius and the time elapsed since nucleation. The resulting model gives quantitative determination of the microstructure developed under a variety of nucleation and growth processes: pre-existing nuclei, constant nucleation, and the combination of both mechanisms, constant and radius dependent growth rates. Comparison with Monte Carlo simulations, showing a quantitative agreement will be presented.

Simultaneous determination of equilibrium and rate constants for first-order reactions

1971 ◽  
Vol 75 (3) ◽  
pp. 430-431 ◽  
Author(s):  
William D. Huntsman ◽  
Johnson C. H. Chen
Keyword(s):  
Simultaneous Determination ◽  
Rate Constants ◽  
First Order

Direkte Bestimmung der Geschwindigkeitskonstanten des Durchtritts vom kleinen zum großen Hohlraumsystem im Molekularsieb Typ 13 X für Sr-und Ba-Ionen / Direct Determination of the Rate Constants for the Sr- and Ba-exchange Between the Small and Large Channels in LMS 13 X

1975 ◽  
Vol 30 (8) ◽  
pp. 951-954 ◽  
Author(s):  
K. Frohnecke ◽  
H. Fischbach
Keyword(s):  
Ion Exchange ◽  
Rate Constants ◽  
Diffusion Coefficients ◽  
Large Diameter ◽  
Direct Determination ◽  
Order Reaction ◽  
First Order Reaction ◽  
First Order ◽  
Total Exchange

Abstract Direct Determination of the Rate Constants for the Sr-and Ba-exchange Between the Small and Large Channels in LMS 13X The rate constants for the intracristalline Sr-and Ba-exchange between the small and large diameter channels of LMS 13X were measured. For this matter the method of interrupting the ion exchange was modified. It is assumed, that a first order reaction takes place. Using the rate constants and the diffusion coefficients, which were measured by Hoinkis and Levi, the total exchange of Sr 2+ and Ba 2+ could be calculated.

In situ determination of PCB congener-specific first order absorption/desorption rate constants using Chironomus tentans larvae (Insecta: Diptera: Chironomidae)

1990 ◽  
Vol 24 (3) ◽  
pp. 321-327 ◽  
Author(s):  
M.A. Novak ◽  
A.A. Reilly ◽  
B. Bush ◽  
L. Shane
Keyword(s):  
Rate Constants ◽  
Chironomus Tentans ◽  
Desorption Rate ◽  
First Order

Determination of First-Order Degradation Rate Constants from Monitoring Networks

Ground Water ◽  
2007 ◽  
Vol 45 (6) ◽  
pp. 774-785 ◽  
Author(s):  
Christof Beyer ◽  
Cui Chen ◽  
Jan Gronewold ◽  
Olaf Kolditz ◽  
Sebastian Bauer
Keyword(s):  
Rate Constants ◽  
Degradation Rate ◽  
Monitoring Networks ◽  
First Order
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