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Abstract  

The concentration of 226Ra, 232Th and 40K has been determined by -ray spectrometry. The measured activity in the selected building materials and by-products of coal fired power plants ranges from 21.5 to 91.3 Bq·kg–1, 15.4 to 63.2 Bq·kg–1 and 83.2 to 683.9 Bq·kg–1 for 226Ra, 232Th and 40K, respectively. The results were compared with the reported data of other countries and with the world average activity of soil. The radium equivalent activities values of all building materials are lower than the limit of 370 Bq·kg–1, equivalent to a -dose of 1.5 mSv·y–1. The values of the external hazard index and the internal radiation hazard index are less than unity.

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Summary  

Due to the widespread use of granites as building and ornamental materials, measurements of 226Ra, 232Th and 40K activities in commercial granites have been carried out using a NaI(Tl)g-ray spectrometer with a matrix-inversion-based spectral stripping technique. The concentrations of 226Ra, 232Th and 40K in Chinese commercial granite range from 14.5 to 204.7 Bq. kg-1, 16.7 to 186.7 Bq. kg-1and 185.7 to 1745.6 Bq. kg-1, respectively. The mean values of the activity concentrations of 226Ra, 232Th and 40K in red and pink commercial granites are all higher than those in black and gray commercial ones. The radium equivalent activity (Raeq), the external hazard index (H ex), the internal hazard index (H in ) and the annual gonadal dose equivalent (AGDE) were also calculated and compared to the international recommended values. Six types of red commercial granites (CBR, MLR, QXR, PBR, JXR, LQR, YDR and TSR) of China do not satisfy the universal standards.

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Abstract  

The influence of the reaction conditions upon the sucrose acid hydrolysis to glucose/fructose equimolecular mixture was investigated, in heterogeneous and homogeneous system, by means of DSC method. The recorded DSC signal was used to evaluate the kinetic parameters and the afferent catalytic constant, k cat 323 values. In homogeneous conditions the used catalyst was acetic acid while in heterogeneous systems a series of carboxylic resins was used as catalysts. The results show a dependence of the kinetic parameters on homogeneous/heterogeneous catalyst nature and on resins experimental properties (cross-linking degree, granulation, porous nature of polymeric matrix, swelling time).

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Abstract  

Using a micro-calorimetrical DSC we have compared the acid-catalyzed inversion of sucrose in homogeneous and heterogeneous systems. Acetic acid was chosen as catalyst for homogeneous system, and several carboxylic cationites were used as heterogeneous catalysts. The kinetic apparent parameters (A, E, k ap) for all the systems were calculated from DSC data with Friedmann’s method and catalytic constant, k323 cat, was further inferred. We found that the specific catalyst efficiency, q cat, in heterogeneous system is over 5000 times higher than in case of homogeneous ones. The activity of heterogeneous carboxylic systems is still about 30 times larger than those of a strong mineral acid in homogeneous catalysis. The results indicate the high efficiency of heterogeneous systems for soft acid catalysis of the sucrose hydrolysis.

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Abstract  

The kinetic parameters (reaction order, n, activation energy, E, pre-exponential factor, A, constant rate, k) for the dehydration step due to elimination of osmotic water and hydrogen-bounded water with the carboxylic groups, and for the anhydrifying step owing to the dehydration of two neighboring (-COOH) groups, were determined under non-isothermal conditions for some carboxylic resins with acrylic-divinylbenzene (DVB) matrix. The kinetic parameters were evaluated by means of isoconversional methods from (TG/DTG) thermal analysis data. The results show a dependence of the apparent kinetic parameters on the cross-linking degree, granulation, gel/macroporous matrix nature, exchange capacity and heating rate.

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Abstract

Synthesis, characterizations, and thermal behavior of Na2[MoO(O2)2(C2O4)] was studied. The thermally induced events will be observed by comparing the FT-IR spectra of the initial compound and of the char at 300 and 500 °C. The TG data were obtained at different heating rates: β = 2.5, 4, 5, and 10 °C min−1 in air and nitrogen (50 mL min−1), and the TG/DTG data were processed with the following methods: Friedman, Flynn–Wall–Ozawa, and modified NPK method.

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Abstract

New solid amorphous compounds of Ce(III), Pr(III), Nd(III), and Sm(III) with 5,7-dihydroxyflavone (L,chrysin) were obtained. Their composition and some physicochemical properties were studied by elementary analysis, thermogravimetric analysis, magnetic measurements, 1H NMR, UV/Vis, and infrared spectroscopies. Upon heating, the hydrated compounds [LnL2(H2O)2Cl]·2H2O decomposed to the oxides. Structure of the compounds was elucidated on the basis of obtained results. It was found that chelation of the metal ion occurs at the 5-hydroxy-4-keto site.

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Abstract

TG/DTG/DTA curves can be used to estimate alimentary fats quality and antioxidants insertion efficiency. Sunflower oil obtained from Carnia hybrid and pork lard were used as matrices for the non-isothermal measurements. The first stage of non-isothermal decomposition is mostly important for the characterization of the fats thermal stability. The corresponding onset temperature is a good value for the comparison of different fats thermal stability or for the effectiveness evaluation in case of antioxidant insertion. In this study, it can be seen a considerable improvement of the fats thermal stability by adding small amounts from a natural antioxidant liquid mixture (obtained by alcoholic maceration of equal amounts of seven plants, namely: milfoil, rosemary, marjoram, thyme, lovage, oregano, and basil). Chlorophylls removal from the plant extract using two different adsorbents was accompanied by a four time decrease of the antiradical activity (measured by the DPPH method) with Sephadex LH20 and seventeen times decrease when activated carbon was used.

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Abstract

In our study, using a combination of eye-tracking parameter analysis and the van Westendorp method, we investigate whether participants pay more attention to products that they perceive as more expensive or to those that they prefer in the ranking process. The experiment involved 50 participants, a questionnaire with ranking and pricing tasks, and an eye-tracking measurement. Three wine varieties (Irsai Olivér, Rosé and Merlot-Shiraz) and three different label alternatives were tested. When comparing the results of the ranking and the pricing tasks, the product that is considered more expensive is not always the one that is most appealing to the participants. If we compare the results from the analysis of the eye-tracking parameters and the pricing, we can say that in all cases the labels that received the most visual attention were those that were priced more expensively by the participants.

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Gulf of Aqaba is a unique marine environment [ 30 ]. The need to balance the Kingdom's only sea ports (a growing industrial zone, which is important to the national economy) with the increasing demand for tourism (due to Jordan's pristine yet fragile

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