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1

Bonitation Analysis of Turf on City Stadium in Wroclaw in the Season of Euro 2012

Wolski K., Janik G., Czarnecki J., Ziarko J., Talar-Krasa M, Walczak A., Biernacik M., Dawid M.

Journal of Ecological Engineering

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2016

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Vol. 17, nr 4

311--320

EN

In 2012–2013, a study was conducted, consisting in a bonitation analysis of turf on the City Stadium which is located in the north-west part of Wroclaw and was a sport arena of the European Championships Euro 2012. The experiment was made with the complete randomisation method for 2 factors, on 5 dates in the growing season. On the turf of the pitch 12 points were selected, and at each of them an evaluation of utility features was performed, in 4 replications, on surface area of 1 m2. Based on the observation of the condition of the turf, during subsequent analyses it was found how the selection of the mixture of grasses, intensity of use and pratotechnic treatments affect the bonitation quality of sport turfgrass. The results are shown in relation to the whole object, separating each of the features under analysis.

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O kierunkach przemian wiązania nadtlenowego i właściwościach utleniających organicznych związków nadtlenowych

Baj S., Dawid M.

Wiadomości Chemiczne

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2000

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[Z] 54, 11-12

1023-1061

EN

Organic peroxides are an interesting group of organic compounds. The O-O bonds in their structure warrant their properties determining the range of their application. The chemistry of peroxy substances is a branch of knowledge which is continuously developing. In the course of recent years much progress has been achieved both in the field of synthesizing new peroxides systems and in applaying them, particularly concerning their biological transformations. A peroxide bond displays a low dissociation energy (20-50 kcal/mol) and that is why they are rather unstable. The reactions of peroxy substances may be divided into homolytic (radical) and heterolytic (ionic) ones. The most popular reaction of the monomolecular homolytic decomposition of the peroxide bond into radicals, occuring under the influence of temperature or radiation, is typical for all classes of peroxy substances and has found practical application. Theretically possible is also a molecular heterolytic decomposition of the peroxide bond into ions. Such a decomposition cannot compete, however, with the homolitic one and is required only in few specific cases. The O-O bond can also undergo transfomations in result of reactions with other substances. Also these reactions may be divided into two fundamental types. Some peroxy substances, e.g. hydroperoxides and peroxy acids, are electron donors and may occur in the reactions as nucleophiles. On the other hand, peroxy substances display the properties of "soft electrophiles" reacting with nucleophilic reagents. The result of such a reaction is a heterolytic decomposition of the peroxide bond. This ambivalent feature of peroxy substances becomes most visible in the natural process of peroxy acids in a basic medium, in which the RCO3- ion plays the role of a nucleophile attacking the non ionized particle (the electrophile). In recent years it has been more and more often stipulated that the reactions of peroxides with nucleophiles run in compliance with the mechanism of the electron transfer (SET) from the nucleophile particle to the oxygen atom of the peroxy bond, in the result of which radicals and radical ions are formed in the course of this reaction. It ought to be stressed that it is extremely difficult to determine the mechanisms of many reactions of peroxy substances explicitly, becouse these types of reactions (SN2, SET) may take place simultaneously and in most cases lesd to the formation of some products.

3

Effect of solvents on the homolytical decomposition of asymmetric dialkyl peroxides

Baj S., Dawid M.

Polish Journal of Chemical Technology

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2000

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Vol. 2, nr 2

1-3

EN

The first-order decomposition rates of asymmetric cumyl propyl peroxide (CPP) in various solvents have been investigated. The differences in rates are discussed in terms of the polar character of reaction transition state. The ratio of reaction products derived from cumyloxyl radical PhC(Me)2O* (1-phenyl-l-ethanon to 2-phenylpropan-2-ol) varies significantly with solvents used.

4

Kinetics of homogeneous decomposition of asymmetric dialkyl peroxides

Baj S., Dawid M.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 9

2151-2158

EN

The homogeneous decomposition of various asymmetric dialkyl peroxides ROOR' (R=C6H5(CH3)2; R'=Et, Pr, Bu, Bu(i), Bu(s), Bu(t), n-heptyl, n-dodecyl and allyl) is examined by the measurement of autooxidation of isopropylbenzene in the presence of peroxides as initiators. Rate constants and activation parameters are determined and the size effect and type of alkyl group R' on stability of O-O bond is discussed.