On Conformational Flexibility of Half-Titanocene Catalysts with Aryloxy Ligands for High-Temperature Olefin Polymerization Processes: Static and Dynamic Theoretical Studies†

2010 ◽  
Vol 29 (21) ◽  
pp. 5341-5352 ◽  
Author(s):  
Monika Srebro ◽  
Łukasz Piȩkoś ◽  
Tae-Jin Kim ◽  
Minserk Cheong ◽  
Myung-Ahn Ok ◽  
...  
Keyword(s):  
High Temperature ◽  
Olefin Polymerization ◽  
Conformational Flexibility ◽  
Theoretical Studies

The model rotator phase

1988 ◽  
Vol 53 (5) ◽  
pp. 889-902
Author(s):  
Josef Šebek
Keyword(s):  
High Temperature ◽  
Partition Function ◽  
Conformational Flexibility ◽  
Small Probability ◽  
Crystalline Phases ◽  
Rotator Phase

It is shown that the formation of the so-called rotator phase of alkanes (one of the high temperature crystalline phases) might be connected with a partial increase of the conformational flexibility of chains. The conformations with higher number of kinks per chain, which have been neglected till now, are shown to contribute effectively to the conformational partition function. Small probability of these states given by the Boltzmann exponent is compensated by a large number of ways in which they can be distributed along the chain. The deduced features of the rotator phase seem to be in agreement with the experimentally observed properties.

Brillouin scattering and theoretical studies of high-temperature disorder in fluorite crystals

1978 ◽  
Vol 11 (15) ◽  
pp. 3197-3212 ◽  
Author(s):  
C R A Catlow ◽  
J D Comins ◽  
F A Germano ◽  
R T Harley ◽  
W Hayes
Keyword(s):  
High Temperature ◽  
Brillouin Scattering ◽  
Theoretical Studies

Optimalization of Tempering Temperature of 9CrNB Steel in Železiarne Podbrezová Steelworks

2017 ◽  
Vol 891 ◽  
pp. 137-142 ◽  
Author(s):  
Ľudovít Parilák ◽  
Pavel Bekeč ◽  
Lucia Domovcová ◽  
Pavol Beraxa ◽  
Milan Mojžiš ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Microstructural Analysis ◽  
Theoretical Studies ◽  
Secondary Phases ◽  
Tempering Temperature ◽  
Carbide Phases ◽  
Hot Rolled ◽  
Martensite Microstructure ◽  
Very High

This paper deals with the optimalization of tempering temperature of 9CrNB steel in Železiarne Podbrezová Steelworks, where hot-rolled tubes were produced with dimensions of 88.9 x 12.51 mm. Austenitising at 1070°C/12m/hr was carried out after rolling, and samples were subsequently tempered at 790°C, 760°C and 720°C/4m/hr. The results of testing the mechanical properties show that only tempering at 790°C fulfilled all of the mechanical properties requirements (Rp0,2, Rm, A5, HBW, KV2). The mechanical properties of grade P92 were used for comparison with 9CrNB mechanical properties, according to the relevant standard of STN EN 10216-2+A2. Yield strength requirements (Rp0,2) were also fulfilled in the temperature range from 100 to 600 °C. Microstructural analysis showed that tempering at 720°C, and also at 760°C does not lead to the complete tempering of martensite microstructure. We observed segregation of secondary phases at the grain boundary, but cementite films between individual laths did not coagulate to form carbide phases. By tempering at 790°C the intensity of formation of carbide phases, coagulation and growth of carbide phases is very high and leads to disintegration of laths. Despite satisfactory results, theoretical studies with respect to the selected chemical composition of 9CrNB steel show that to achieve sufficient dissolution of carbide or nitride phases (especially BN), it is necessary to use high temperature austenitization up to about 1200°C, followed by tempering below Ac1.

scholarly journals Theoretical studies on the calculation of the noise of impact equipment in blacksmith shops

2020 ◽  
Vol 164 ◽  
pp. 01030 ◽  
Author(s):  
Elena Staseva ◽  
Dmitry Larin ◽  
Sergei Demchenko ◽  
Kirill Kobzev
Keyword(s):  
High Temperature ◽  
Noise Reduction ◽  
Impulse Noise ◽  
Theoretical Studies ◽  
Economic Significance ◽  
Temperature Manipulation

Most types of forging equipment relate to impact machines, during the operation of which impulse noise occurs, the levels of which at workplaces, in most cases, exceed the maximum permissible values and relate to those factors, the significance of which in some cases is greater than dustiness, high temperature, manipulation of heated workpieces. Therefore, the problem of reducing vibration and noise in the forge shops is extremely relevant and has great scientific and socio-economic significance. To solve the problem of noise reduction in forge shops, various options for reducing the noise activity of equipment have been developed/ It is possible to most effectively reduce noise by changing the material and shapes of the beds, noise-attenuating casings, oil baths for gears.

Theoretical Studies of Copper Oxide Clusters: Prediction of an Electronically Driven Phase Separation in YBa2Cu3Ox

1987 ◽  
Vol 99 ◽  
Author(s):  
L. A. Curtiss ◽  
T. O. Brun ◽  
D. M. Gruen
Keyword(s):  
Phase Diagram ◽  
Phase Separation ◽  
High Temperature ◽  
Copper Oxide ◽  
Superconducting Phase ◽  
Oxygen Stoichiometry ◽  
Molecular Orbital Calculations ◽  
Theoretical Studies ◽  
Two Phases ◽  
Semi Empirical

ABSTRACTOn the basis of semi-empirical extended Hiickel molecular orbital calculations of copper-oxide clusters representing the new superconducting material YBa2Cu3Ox, a phase diagram is proposed which suggests that the 94 K high temperature superconducting phase of YBa2Cu3Ox is characterized by an oxygen stoichiometry near 7.0. The phase diagram predicts that a plateau should exist for Tc in the region x = 0.0 – 0.25 and that in this region two phases are present which are characterized by compositions having oxygen stoichiometries 6.5–6.75 and ca. 7.0.

scholarly journals Average atom model and EOS calculations: DFT approach

1992 ◽  
Vol 10 (2) ◽  
pp. 277-298 ◽  
Author(s):  
L. Drska ◽  
M. Sinor
Keyword(s):  
High Temperature ◽  
Inertial Confinement Fusion ◽  
Density Functional ◽  
Extreme Conditions ◽  
Inertial Confinement ◽  
Theoretical Studies ◽  
Ionization State ◽  
Functional Formalism ◽  
Confinement Fusion ◽  
Average Atom Model

The knowledge of the properties of atoms in high-temperature/density plasmas is of deep interest in many fields of physics. Theoretical studies and interpretation of the inertial confinement fusion experiments is one of the examples. On the basis of the density functional formalism, a model of matter at extreme conditions is presented. Application of the model is illustrated by examples of average ionization state and equation of state calculations.

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