Interplay between the Gentlest Ascent Dynamics Method and Conjugate Directions to Locate Transition States

The pyrolysis of methyl alkyl esters I to III and dithioesters IV to VI were theoretically calculated. All possible pyrolysis paths were considered. Both esters and dithioesters presented three potential paths via six-, four- and five-membered ring transition states, respectively. The calculation processes were calculated using MP2/6-31G(d) set. In-depth theoretical analyses were also presented, including NBO related analyses, synchronicities, and charge distributions, to reveal the detailed pyrolysis process.

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Modeling Nano-Metric Manufacturing Processes with Molecular Dynamics Method: A Review

Current Nanoscience ◽

10.2174/1573413712666160530122851 ◽

2016 ◽

Vol 13 (1) ◽

pp. 3-20 ◽

Cited By ~ 3

Author(s):

Nikolaos E. Karkalos ◽

Angelos P. Markopoulos

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Method ◽

Manufacturing Processes ◽

Dynamics Method

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Sterically Crowded Heterocycles. X. A New Mechanistic Approach to the Ferricyanide Oxidation of 4,6'-Disubstituted 1-(Pyridin-2'-yl)-2,6-diphenylpyridinium Salts

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19991274 ◽

1999 ◽

Vol 64 (8) ◽

pp. 1274-1294 ◽

Cited By ~ 5

Author(s):

Radek Pohl ◽

Stanislav Böhm ◽

Josef Kuthan

Keyword(s):

Transition States ◽

Oxidative Transformation ◽

Steric Interactions ◽

Radical Intermediates ◽

Mechanistic Approach

The oxidations of the title perchlorates, bearing the sterically diverse 6'-substituents (H, Me, Et, i-Pr, n-Bu, t-Bu and Ph) in two series with the same 4-substituents (Ph and t-Bu) lead to pairs of isomeric 3',5-disubstituted (Z)-1'-phenyl-3'-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2'- en-1'-ones and 3,6'-disubstituted [5-phenyl-1-(6'-pyridin-2'-yl)-1H-pyrrol-2-yl](phenyl)methanones except where the both variable substituents are t-Bu and then only pyrrolic product is formed. Considering steric interactions of the substituents in some intermediate and/or transition states a multistep mechanism for the oxidative transformation is proposed and supported by model PM3-PECI calculations of some radical intermediates.

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Development, Modeling and Control of a Dual Tilt-Wing UAV in Vertical Flight

Drones ◽

10.3390/drones4040071 ◽

2020 ◽

Vol 4 (4) ◽

pp. 71

Author(s):

Luz M. Sanchez-Rivera ◽

Rogelio Lozano ◽

Alfredo Arias-Montano

Keyword(s):

Dynamic Model ◽

Attitude Control ◽

Test Bench ◽

Aerodynamic Coefficients ◽

Nonlinear Dynamic Model ◽

Modeling And Control ◽

Drag And Lift ◽

And Control ◽

Dynamics Method ◽

Indoor And Outdoor

Hybrid Unmanned Aerial Vehicles (H-UAVs) are currently a very interesting field of research in the modern scientific community due to their ability to perform Vertical Take-Off and Landing (VTOL) and Conventional Take-Off and Landing (CTOL). This paper focuses on the Dual Tilt-wing UAV, a vehicle capable of performing both flight modes (VTOL and CTOL). The UAV complete dynamic model is obtained using the Newton–Euler formulation, which includes aerodynamic effects, as the drag and lift forces of the wings, which are a function of airstream generated by the rotors, the cruise speed, tilt-wing angle and angle of attack. The airstream velocity generated by the rotors is studied in a test bench. The projected area on the UAV wing that is affected by the airstream generated by the rotors is specified and 3D aerodynamic analysis is performed for this region. In addition, aerodynamic coefficients of the UAV in VTOL mode are calculated by using Computational Fluid Dynamics method (CFD) and are embedded into the nonlinear dynamic model. To validate the complete dynamic model, PD controllers are adopted for altitude and attitude control of the vehicle in VTOL mode, the controllers are simulated and implemented in the vehicle for indoor and outdoor flight experiments.

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