scholarly journals Contamination Studies on Mollusk Shell Samples

Radiocarbon ◽  
1985 ◽  
Vol 27 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Tomasz Goslar ◽  
Mieczysław F Pazdur
Keyword(s):  
Carbon Dioxide ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Solid State ◽  
Carbon Exchange ◽  
Laboratory Contamination ◽  
Mollusk Shell

A series of shell samples has been studied to determine the magnitude and mechanisms of carbon exchange between shells and their environment. Laboratory contamination experiments included the storing of shell samples in acid and calcareous environments of different 14C concentrations as well as studies of carbon exchange in the course of thermal recrystallization in solid state in an atomosphere of carbon dioxide. The applicability of differential thermal analysis to studies of the structure and texture of shells is discussed.

Kinetics of temperature-programmed reactivation of a hydrodesulphurization catalyst

1983 ◽  
Vol 48 (12) ◽  
pp. 3340-3355 ◽  
Author(s):  
Pavel Fott ◽  
Pavel Šebesta
Keyword(s):  
Carbon Dioxide ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thin Layer ◽  
Kinetic Parameters ◽  
Diffusion Region ◽  
Reaction Heat ◽  
Gaseous Products ◽  
Temperature Programmed ◽  
Kinetics Of

The kinetic parameters of reactivation of a carbonized hydrodesulphurization (HDS) catalyst by air were evaluated from combined thermogravimetric (TG) and differential thermal analysis (DTA) data. In addition, the gaseous products leaving a temperature-programmed reactor with a thin layer of catalyst were analyzed chromatographically. Two exothermic processes were found to take part in the reactivation, and their kinetics were described by 1st order equations. In the first process (180-400 °C), sulphur in Co and Mo sulphides is oxidized to sulphur dioxide; in the second process (300-540 °C), in which the essential portion of heat is produced, the deposited carbon is oxidized to give predominantly carbon dioxide. If the reaction heat is not removed efficiently enough, ignition of the catalyst takes place, which is associated with a transition to the diffusion region. The application of the obtained kinetic parameters to modelling a temperature-programmed reactivation is illustrated on the case of a single particle.

Preparation and Characterization of the New Y257 Superconductors

2013 ◽  
Vol 770 ◽  
pp. 22-25 ◽  
Author(s):  
Thitipong Kruaehong
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Critical Temperature ◽  
Solid State ◽  
Superconducting Phase ◽  
Lattice Parameters ◽  
Peritectic Temperature ◽  
Space Group ◽  
Space Groups

The new Y257 superconductor in YBaCuO family was synthesized by standard solid state reaction. The Y257 samples were measured the critical temperature (Tc) by the four-probes method that found at 90 K. The XRD technique and FULLPROF program were used to determine the lattice parameters, space group and phase compositions. It was found that the Y257 exhibited in both of superconducting and non-superconducting phase. The Pmmm space group was fit well on superconducting phase with the lattice parameters as a=3.8108 Å, b=3.8544 Å and c=26.4967 Å. The non-superconducting phase exhibited in two space groups of Pccm (a=12.9770 Å, b=20.54780 Å and c=11.3530 Å) and Im-3m (a= 18.2104 Å, b=18.2104 Å and c=18.2104 Å). The peritectic temperature at 976.73°C was measured by differential thermal analysis.

scholarly journals DTA/TG analysis of mechanochemicaly activated sodium carbonate

2021 ◽  
pp. 47-55
Author(s):  
Nataša Đorđević ◽  
Slavica Mihajlović ◽  
Gvozden Jovanović ◽  
Branislav Marković
Keyword(s):  
Carbon Dioxide ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Relaxation Time ◽  
Environmental Protection ◽  
Sodium Carbonate ◽  
Room Temperature ◽  
Tg Analysis ◽  
Relaxation Period ◽  
Sorption Characteristics

Sodium carbonate is a material that is very good sorbent of carbon dioxide from the atmosphere, and it is a reason of it is increasing importance in environmental protection. In order to improve it is sorption characteristics, activation of Na2CO3 was performed by mechanochemical procedure and monitoring of changes during the relaxation time. This research is based on differential thermal analysis with thermogravimetry, in order to determine the changes that occurred on the activated samples during the relaxation period under controlled conditions. Sodium carbonate was activated for 2 and 7 minutes in a vibro mill, and then the activated samples were deposited in at room temperature and atmosphere of carbon dioxide at a humidity of 95% for 96h.

scholarly journals Synthesis and thermal studies of solid state 2-chloro-benzylidenepyruvic acid and its compounds with sodium, aluminium (III), gallium (III) and indium (III) cations

2004 ◽  
Vol 29 (1) ◽  
pp. 31-40 ◽  
Author(s):  
G. Bannach ◽  
E. Schnitzler ◽  
C. B. Melios ◽  
M. Ionashiro
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Differential Thermal Analysis ◽  
Solid State ◽  
Chemical Analysis ◽  
Thermal Behaviour ◽  
Thermal Studies ◽  
X Ray ◽  
Derivative Thermogravimetry

The synthesis of sodium 2-chlorobenzylidenepyruvate and its corresponding acid as well as binary, binary together with it's acid or hydroxo-2-chorobenzylidenepyruvate of aluminium (III), gallium (III) and indium (III), were isolated. Chemical analysis, thermogravimetry, derivative thermogravimetry (TG/DTG), simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and X-ray powder diffractometry have been employed to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the stoichiometry, crystallinity, thermal stability and thermal decomposition.

scholarly journals Synthesis, characterization and thermal behaviour of solid-state compounds of 4-methoxybenzoate with lanthanum (III) and trivalent lighter lanthanides

2006 ◽  
Vol 31 (1) ◽  
pp. 21-30 ◽  
Author(s):  
E. C. Rodrigues ◽  
A. B. Siqueira ◽  
E. Y. Ionashiro ◽  
G. Bannach ◽  
M. Ionashiro
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Differential Thermal Analysis ◽  
Solid State ◽  
Thermal Behaviour ◽  
Polymorphic Transformation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Lighter Lanthanides

Solid-state M-4-MeO-Bz compounds, where M stands for trivalent La, Ce, Pr, Nd and Sm and 4-MeO-Bz is 4-methoxybenzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, polymorphic transformation, ligand's denticity, thermal behaviour and thermal decomposition of the isolated compounds.

Solid State Formation of Superconducting Phases in the T1-Ca-Ba-Cu-O System

1989 ◽  
Vol 169 ◽  
Author(s):  
T.W. Huang ◽  
M.P. Hung ◽  
T.S. Chin ◽  
H.C. Ku ◽  
S.C. Yang ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Solid State ◽  
Activation Energies ◽  
Kcal Mole ◽  
Preparation Methods ◽  
High Tc ◽  
Superconducting Phases ◽  
The One ◽  
Flowing Oxygen

AbstractDifferential thermal analysis (DTA) and thermal gravitometry analysis (TG A) under flowing oxygen show that the formation temperatures of the high Tc T12Ca2Ba2Cu3Ox (2223) and the low Tc T12CaBa2Cu2Ox (2212) phases lie at around 910 °C and 840 °C, respectively. The activation energies are as low as 50 kcal/mole for the 2223 phase and 35 kcal/mole for the 2122 phase. Thus the time for the formation of these phases can be within 30 minutes.Two preparation methods were tried, and the one with Ca3BaCu3O7 as a precursor was easier to attain pure high Tc 2223 phase than that prepared directly from component oxides and carbonates.

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