In the present manuscript, freshly prepared and also pure chemical grade (BDH) antimony trioxide specimens were investigated. Numerous measurements were carried out on these specimens, comprising chemical, spectral and X-ray analyses, pycnometric and X-ray density measurements and observations of the behaviour of the dielectric constant and dielectric loss factor (∈′ and ∈″) as functions of temperature and frequency. The results obtained gave values of 12.4 and 10 for the dielectric constant for the freshly prepared and commercial antimony trioxide specimens, respectively. The results were compared in correlation with the phase constitution and degree of compactness for both specimens. Finally, the data are discussed on the basis of the interactions of the field frequency and temperature with the electric dipoles and electronic polarization of the test specimens.
complex process that depends on the chemical constitution and physical structure of macromolecules as well as on the chemical reactions and physical phenomena taking place in the sample under testing, its boundary layer and flame.
Authors:Przemysław Rybiński, Grażyna Janowska, Agnieszka Kucharska-Jastrząbek, Agnieszka Pająk, Iwona Wójcik, Dorota Wesołek and Krzysztof Bujnowicz
combination of polymer macromolecules with crosswise bonds, prevents this phenomenon to an extent dependent on the chemical constitution and physical structure of elastomer, and the structure of spatial network and cross-link density [ 2 – 5 ]. The formation
CuCl2-KCl mixtures were annealed at 603 K and thermogravimetrically analysed after cooling to room temperature. The mixtures differed in the molar ratio Cu/K and in the duration of heating at 603 K. The constitutions of the ions, the reactions between them and the mechanisms of their decomposition in the melt are proposed, as are the constitutions of the active centres in the oxychlorination process.
stage of decomposition of the α-amino acids depends much on chemical constitution of the analysed compounds. At this stage, which runs with several dozen per cent of the loss of mass, partial degradation of anhydrous substance with the formation of
Authors:Linping Zhang, Xianlei Song, Yanyan Song, Zhanbo Sun, Qian Li, Xiaoping Song and Liqun Wang
thermal effect on . (3) It is not necessary to distinguish the phase constitution of solid alloys when the equal-G point method is adopted.
It is necessary to indicate that the method developed in this paper has own limitations. (1) Thermodynamic
Several samples of native (untreated), mercerized prior to ammonia treatment and ammonia-treated Egyptian cotton fabric strips have been prepared. On these samples several measurements were carried out, including infrared and electronic absorption spectroscopy, temperature dependent DC electric conductivity measurements and -radiation exposure. Detailed accounts of the spectral properties and phase constitution of NH3-treated cotton celluloses were correlated with their electrical properties. Finally, the mechanism of electric conduction in NH3-treated Egyptian fabric strips was put forward and correlated for the first time with the spectral properties and phase constitution of cotton textiles.
Authors:R. Godinho, H. Wolterbeek, M. Pinheiro, L. Alves, T. Verburg and M. Freitas
The elemental microdistributions of peripheral and central parts of the lichen Flavoparmelia caperata exposed to industrial pollution were analysed, in order to better understand the elements distribution patterns in relation
to the lichen constitution, thereby increasing our knowledge on uptake and release mechanisms. Nuclear microscopy techniques
were used to visualize elemental distributions in sample transepts and associate their concentrations to sample morphology.
The distribution data of the elements studied suggests there is biological regulation of internal concentrations. Considering
thallus parts, element-specific internal translocation should be taken into account as one more factor affecting lichen “memory
The influence of substituents on the thermal decomposition of monomeric organic compounds was studied. For this purpose the thermal destruction of dozen or so α-amino acids of the diversified chemical constitution, among others compounds containing the second amine group, additional carboxyl group, amino acids containing hydroxyl or sulfhydryl groups and amino acids connected with five-member heterocyclic ring or existing in the form of hydrates or hydrochlorides were investigated. The analyses were performed using a derivatograph in an air atmosphere, sample sizes were from 50 to 200 mg and heating rate from 3 to 15 K min-1. It has been established that the thermal decomposition of studied compounds occurs in three stages. The temperature ranges, in which the analyzed compounds undergo thermal transformations were established. For evaluation of the thermoanalytical results an advanced multivariate data processing method, principal component analysis (PCA), was used. By this method the influence of the specific functional groups on the thermal decomposition of α-amino acids was determined. The stage of decomposition, in which the thermoanalytic data are the best correlated to the chemical constitution of the compound, is the second stage. It has also been recognized, that better discrimination among the analyzed compounds was obtained for the data set of the DTA.