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The reduction of BaSO4 by carbon was investigated by means of isothermal thermogravimetric measurements. In combination with a high-temperature thermobalance, solid electrolyte cells were used (i) to purify the N2 flow gas, and (ii) to measure the partial pressure of oxygen (CO∶CO2 ratio, respectively) in the outlet gases.

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Abstract  

Transpiration method was used to measure the equilibrium water vapor pressures of the dehydration of the respective hydrates, such as oxalates, sulfates,chlorides and acetate, and the enthalpies of dehydrations (ΔH Tr 0) of these hydrates were obtained. The heats of dehydrations (ΔH DSC 0) were also determined by TG-DSC method. From the comparison with ΔH Tr 0 of ΔH DSC 0, the relation of ΔH DSC 0H Tr 0=R (=dehydration molar number determined by TG-DSC peak/stoichiometric dehydration molar number) was yielded. From these results, the following relations were found: ΔH DSC 0(corrected)=ΔH DSC 0/RH Tr 0

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The thermal analysis and kinetics of oxidation of “NbS2” to Nb2O5 were studied by thermogravimetry. The application of both isothermal and nonisothermal methods was necessary to establish the correct equation
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$1 - (1 - \alpha )^{1/3} = kt$$ \end{document}
This equation was valid for the reaction of sample reactedα in the interval 0.03 to 0.82–0.91. The apparent activation energy was determined to be 209.59±2.36 kJ mol−1 with the isothermal method and 209.28±1.84 kJ mol−1 with the nonisothermal method (5 deg min−1) over thePo2 range 8.9×10−2 to 2.0×10−1 atm and the temperature range 440 to 515°. The relationship between the rate constantk andPo2 was also determined.
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The phase diagram of the La-S-O system at 1073 K was established with the vacuum seal technique. Six phases exist at this temperature: La2O3 (B-type), LaS2, La2S3, La2O2SO4, La2O2S and La2O2S2. The thermodynamic functions for the reaction La2O2SO4=La2O3+SO2+1/2 O2 were determined by using the emf method at temperatures from 1123 to 1373 K. The mechanisms of the oxidation reactions in the La-S-O system under different partial pressures of oxygen (−4.4 < log <−0.7) were also investigated by means of DTA, TG and powder X-ray diffractometry.

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Summary Using a thermal relaxation calorimetry technique, we have measured heat capacities of κ-(BEDT-TTF)4Hg2.89Br8 system under magnetic fields between 0 and 6 T. With the increase of cooling rate from room temperature to liquid helium temperature, we have observed a remarkable but systematic tendency that the thermal anomaly associated with the superconductive transition shifts to the lower temperatures. The course of this phenomenon is attributable to the degree of disorder in the mercury chains which give an incommensurate potential to the superconducting planes.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
N. Momoshima
,
F. Inoue
,
T. Ohta
,
Y. Mahara
,
J. Shimada
,
R. Ikawa
,
M. Kagabu
,
M. Ono
,
K. Yamaguchi
,
S. Sugihara
, and
M. Taniguchi

Abstract  

Groundwater age was determined by 85Kr/Kr specific activity of gases dissolved in groundwater at Kumamoto Area, in which newly developed Kr extraction system and liquid scintillation counting technique for 85Kr were applied. Apparent mean residence times observed were 8.2 ± 0.7 years and 20.7 ± 0.6 years for the groundwater taken from a well at the recharge area and that from an artesian borehole at the discharge area, respectively showing a consistent age trend estimated from the observed groundwater flow system of Kumamoto Area and also that determined using environmental tritium. Similar mean residence times of 85Kr and tritium were observed at the discharge area but the mean residence time of 85Kr at the recharge area was younger compared to that of tritium, probably due to mixing of river water containing recent 85Kr high in concentration into groundwater flow coming from the northern upland’s recharge area. The mean residence time of the groundwater flow coming from northern upland area and a traveling time of the groundwater between two sampling points were estimated by a simple model assuming mixing the river water with the groundwater and a piston flow between two sampling points.

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