scholarly journals Experimental Determination of Thermal Stability of Metalorganic Compounds in Volcanic Olivines

2020 ◽  
Author(s):  
Joanna Brau ◽  
Marco Matzka ◽  
Bettina Scheu ◽  
Norbert Hertkorn ◽  
Philippe Schmitt-Kopplin ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Experimental Determination ◽  
Metalorganic Compounds ◽  
Thermal Stability Of

Determination of the Thermal Stability of Explosives

2021 ◽  
Vol 15 (2) ◽  
pp. 271-277
Author(s):  
G. M. Nazin ◽  
B. L. Korsunskiy
Keyword(s):  
Thermal Stability ◽  
Thermal Stability Of

Thermal stability of metalorganic compounds on volcanic olivine

2020 ◽  
Author(s):  
Joanna Brau ◽  
Marco Matzka ◽  
Philippe Schmitt-Kopplin ◽  
Norbert Hertkorn ◽  
Werner Ertel-Ingrisch ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Treatment ◽  
Tube Furnace ◽  
Stability Field ◽  
Secondary Phases ◽  
The Stability ◽  
The Individual ◽  
Gas Tight ◽  
Metalorganic Compounds ◽  
Thermal Stability Of

<p>Previously unknown class of metalorganic compounds revealed in meteorites [1] also found on the surfaces of silicate phases such as olivine, may have been involved in the emergence of life.  Here, the thermal stability of such organic compounds has been experimentally investigated under conditions which simulate those extant on the early Earth. We have studied olivines from the Hawaiian eruptions of 1959 and 2018. Individual mineral grains have been hand-picked to be free of secondary phases such as pyroxene or melt. We use a high temperature gas-tight tube furnace under CO-CO<sub>2</sub> gas mixture at temperatures ranging from 950°C to 1350°C and oxygen fugacity ranging from 10<sup>-12</sup> to 10<sup>-10 </sup>bar, within the stability field of olivine. The samples were contained in Pt crucibles and held for dwell times of 1 to 64 h. Quenching was performed by lifting the samples vertically out of the tube furnace. Using EPMA (electron microprobe analyzer) and RAMAN spectroscopy, we have mapped the state of the olivine samples. We observe that the composition of the individual mineral grains remains stable and homogeneous with thermal treatment. We are also investigating the role of impurities and cracks in the natural olivine and synthetic forsterite that might influence our study. The metalorganic cargo of these olivines has been analyzed using FT-ICR-MS (Fourier Transform ion cyclotron mass spectrometry). Preliminary results reveal systematic changes or organic molecular composition depending on time and heat of thermal treatment whose origins will be discussed.</p><p>[1] A. Ruf, B. Kanawati, N. Hertkorn, Q. Yin, F. Moritz, M. Harir, M. Lucio, B. Michalke, J. Wimpenny, S. Shilobreeva, B. Bronsky, V. Saraykin, Z. Gabelica, R. D. Gougeon, E. Quirico, S. Ralew, T. Jakubowski,  H. Haack, M. Gonsior, P. Jenniskens, N. W. Hinman, P. Schmitt-Kopplin. (2017) Previously unknown class of metalorganic compoundsrevealed in meteorites. PNAS 114 (2017) 2819-2824.</p>

Determination of thermal stability of oils by pyrolytic gas chromatography

1983 ◽  
Vol 19 (8) ◽  
pp. 412-414
Author(s):  
N. A. Kudryavtseva ◽  
I. A. Mikhailov ◽  
E. M. Nikonorov ◽  
L. A. Rakova
Keyword(s):  
Thermal Stability ◽  
Gas Chromatography ◽  
Thermal Stability Of

scholarly journals The Modification of Polyurethane Foams Using New Boroorganic Polyols (II) Polyurethane Foams from Boron-Modified Hydroxypropyl Urea Derivatives

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Iwona Zarzyka
Keyword(s):  
Thermal Stability ◽  
Boric Acid ◽  
Water Absorption ◽  
Propylene Carbonate ◽  
Dimensional Stability ◽  
Polyurethane Foams ◽  
Urea Derivatives ◽  
Nitrogen Ratio ◽  
Thermal Stability Of

The work focuses on research related to determination of application possibility of new, ecofriendly boroorganic polyols in rigid polyurethane foams production. Polyols were obtained from hydroxypropyl urea derivatives esterified with boric acid and propylene carbonate. The influence of esterification type on properties of polyols and next on polyurethane foams properties was determined. Nitrogen and boron impacts on the foams’ properties were discussed, for instance, on their physical, mechanical, and electric properties. Boron presence causes improvement of dimensional stability and thermal stability of polyurethane foams. They can be applied even at temperature 150°C. Unfortunately, introducing boron in polyurethanes foams affects deterioration of their water absorption, which increases as compared to the foams that do not contain boron. However, presence of both boron and nitrogen determines the decrease of the foams combustibility. Main impact on the decrease combustibility of the obtained foams has nitrogen presence, but in case of proper boron and nitrogen ratio their synergic activity on the combustibility decrease can be easily seen.

scholarly journals The preparation of nylon-tube-supported hexokinase and glucose 6-phosphate dehydrogenase and the use of the co-immobilized enzymes in the automated determination of glucose.

1975 ◽  
Vol 147 (3) ◽  
pp. 593-603 ◽  
Author(s):  
D L Morris ◽  
J Campbell ◽  
W E Hornby
Keyword(s):  
Thermal Stability ◽  
Automated Analysis ◽  
Immobilized Enzymes ◽  
Nylon Tube ◽  
The Individual ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Thermal Stability Of ◽  
Automated Determination

Triethyloxonium tetrafluoroborate was used to O-alkylate nylon-tube thus producing the imidate salt of the nylon which was further made to react with 1,6-diaminohexane. 2. Hexokinase (EC 2.7.1.1) and glucose 6-phosphate dehydrogenase (EC 1.1.1.49) were immobilized on the amino-substituted nylon tube through glutaraldeyde and bisimidates. 3. The effect of varying the conditions of O-alkylation and the amount of enzyme immobilized on the activity of nylon tube-hexokinase derivatives was determined. 4. The effect of varying the amount of enzyme immobilized on the activity of nylon-tube-glucose 6-phosphate dehydrogenase derivatives was determined. 5. The thermal stability of nylon-tube-hexokinase and nylon-tube-glucose 6-phosphate dehydrogenase derivatives was studied. 6. Different ratios of hexokinase and glucose 6-phosphate dehydrogenase were co-immobilized on nylon tube, and the rate of conversion of glucose into 6-phosphogluconolactone was compared with the individual activities of the immobilized enzymes. 7. Hexokinase and glucose 6-phosphate dehydrogenase co-immobilized on nylon tube were used in the automated analysis of glucose.

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