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Abstract  

The curing characteristics of adicyandiamide-cured epoxy system under the influence of solvents in a closed environment were studied by means of isothermal differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The DSC analyses revealed that the presence of solvent results in decreases in the curing exotherm, the initial curing rate, the glass transition temperature, the reaction rate and the reaction order of the epoxy resin. The greatest decreases were caused by the solvent with the highest boiling temperature. A change in temperature-dependent curing route due to the heat absorbed during solvent evaporation is responsible for the difference. The FTIR analyses confirmed that the composition of the cured resin is affected by the solvent, the curing temperature and the specimen configuration. As compared with those obtained from open systems, specimens produced in a closed environment have an enhanced curing exotherm, initial curing rate, glass transition temperature, reaction rate and reaction order because of the retention of volatile catalytic by-products.

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Acta Botanica Hungarica
Authors: T. O. Kondratiuk, S. Y. Kondratyuk, M. V. Khimich, T. V. Beregova, and L. I. Ostapchenko

-like fungi Exophiala alcalophila Goto et Sugly from hermetic damaged in conditions of indoor high humidity . – Modern Phytomorph. 3 : 225 – 229 . Kondratyuk , T. and Kalinichenko , A

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Abstract  

The paper deals with verification of the continuous way coating hermeticity sealing of fuel elements control by means of two mutually independent ways of verification of the heating courses of primary circuit cooler.

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Abstract  

The phase transitions occurring in aqueous solutions of macromolecules and their complex structures (like order-disorder transitions in proteins or nucleic acids solutions) are usually accompanied by small changes in their specific partial volumes. If the quantity of these substances in the closed calorimetric vessels is relatively large (few mg) and if the phase transition is accompanied by a high change of specific partial volume (like in solution of bacteriophages),it is possible to detect some imaginary heat effects in the DSC calorimeters which have closed (sealed) vessels with free volume above the liquid.

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Timaios mítosza és a kozmológiai princípiumok

Megjegyzések Plótinos II. 9-hez

Antik Tanulmányok
Author: Endre Ádám Hamvas

Plótinos az Azok ellen, akik a világ teremtőjét rossznak, s a világot rútnak mondják című művében azt írja, hogy a gnóstikusok nem tesznek mást, mint Platón Timaios át magyarázzák félre. A cikkben ebből a kijelentésből kiindulva kísérlem meg felvázolni azokat a problémákat, amelyek a Timaios kozmológiai leírásának hatására jelentek meg a későbbi természetfilozófiai elképzelésekben a platonikus, továbbá a gnóstikus és hermetikus kozmológiákban. E kérdésben alapvető a Démiurgos alakjának szerepe, illetve a platóni befogadó fogalmának értelmezése. A kérdés vizsgálata során először a platóni szöveg kozmológiai fogalmait (az örök képmás-Démiurgos-befogadó) vizsgálom, majd vázolom, hogyan alakult át a befogadó fogalom a későbbi platóni gyökerű filozófiák anyag , illetve hely terminusaivá. E fogalmi keretben válik érthetővé és vizsgálhatóvá a plótinosi kijelentés. A gnóstikusokkal kapcsolatban annak a bemutatása a legfontosabb, hogy a Plótinos által kárhoztatott dualisztikus kozmológiájuk - ahogyan azt maga Plótinos erősíti meg - a platóni szöveg interpretációs lehetőségein nyugszik. Az Asclepius című hermetikus dialógus jó példája annak, hogyan jelenhet meg később az Isten mellett létező preegzisztens kozmológiai princípium egyszerre, mint anyag és hely , míg a CH VIII. szöveg szerinti párhuzamokat mutat a Timaios szal. Mindemellett természetesen nem zárhatjuk ki más (főképpen keleti) hatások lehetőségét, de a platóni filozófia fogalmainak vizsgálata jelentős szempontokat adhat annak vizsgálatához, hogy milyen hatások játszhattak szerepet a késő ókori dualista kozmológiák kialakulásában.

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The Hermetic dialogue Asclepius occupies a central place in the Corpus Hermeticum. One part of Asclepius and the prayer at its end was translated into Coptic from Greek. This paper examines the richness of Egyptian thought incorporated into the dialogue and demonstrates the close relations between the work and Hellenistic Egyptian religion.

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Abstract  

Thermal degradation of atrazine and its metabolites has been investigated using a thermogravimetric technique(TG) with the application of three types of crucibles: opened, Knudsen type and labyrinthtype, and non-isothermal DSC method, using hermetically closed and opened alumina sample pans. The great influence of decomposition conditions (the crucible type) on thermal degradation was observed. TG analysis showed that the degradation process of atrazine took place in three stages. The increase of amino groups in triazine ring increases the amount of non-volatile thermal degradation products by association. The presence of chlorine substituent facilitates the forming of products with low volatility. Hydroxyatrazine decomposes only in one stage process. The dealkylation process observed in hermetical sample pans (DSC) was two-stage and in open sample pans one-stage process.

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Abstract  

Cyanazine was taken as an example for investigations under the influence of different conditions on thermal decomposition of triazine herbicides. DSC measurements were carried out under atmospheric pressure and hermetically closed, under pressure 1.3 kPa. The influence of the pressure on the constant reaction rate of decomposition of cyanazine was discussed. It was also proved that the predicted reaction constant rates from isothermal and non-isothermal measurements are consistent.

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Abstract  

For a large number of DSC calibration substances the vapour pressure at room temperature or at transition temperature (whichever is the highest) is given. It is important to know the vapour pressure of substances, because a DSC measurement on a substance with a high vapour pressure requires encapsulation of the substance in a hermetically sealed crucible to prevent evaporation. Because the calibration procedure must be performed using the same type of sample pan as will be used during the actual measurements, the presented information allows one to decide which calibration substances and/or what type of sample pan should be used for calibration.

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Abstract  

Plastically deformed samples of ultra high purity iron (UHP) doped with 150 ppm of niobium were investigated by differential temperature scanning calorimetry (DTSC) determining the stored energy and the activation enthalpy of recovery and recrystallization. Any oxidation effects were successfully prevented with a newly constructed device for cleaning the specimens by ion-etching and enclosing them hermetically in noble metal capsules without any contact to air. Compared with pure iron the stored energy and the activation enthalpy are increased in the Fe–Nb alloy resulting in a large shift of the recrystallization temperature.

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