Dynamics and thermodynamics of the coronene octamer described by coarse-grained potentials

2017 ◽  
Vol 19 (3) ◽  
pp. 1884-1895 ◽  
Author(s):  
J. Hernández-Rojas ◽  
F. Calvo ◽  
S. Niblett ◽  
D. J. Wales

Coarse-grained models developed for polycyclic aromatic hydrocarbons based on the Paramonov–Yaliraki potential have been employed to investigate the finite temperature thermodynamics, out-of-equilibrium dynamics, energy landscapes, and rearrangement pathways of the coronene octamer.

2019 ◽  
Vol 21 (9) ◽  
pp. 5123-5132 ◽  
Author(s):  
J. Hernández-Rojas ◽  
F. Calvo

The aggregation and physical growth of polycyclic aromatic hydrocarbon molecules was simulated using a coarse-grained potential and a stochastic Monte Carlo framework. In agreement with earlier studies, homomolecular nucleation of pyrene, coronene and circumcoronene is found to be limited at temperatures in the 500–1000 K range. Heteromolecular nucleation is found to occur with a minor spontaneous segregation toward pure and equi concentrations.


2020 ◽  
Vol 4 (2) ◽  
pp. 58-65
Author(s):  
Ovuru Cyril ◽  
Leizou ◽  
Kaywood Elijah ◽  
Muhammad Aqeel Ashraf

AbstractThe aim of this study was to evaluate the polycyclic aromatic hydrocarbons load in soils of Ogale community, Rivers State, Nigeria and as well delineate the lateral and vertical extensions of the soils and groundwater. Geo-electric characterization of the soils and groundwater, using Electrical Resistivity methods (vertical electrical sounding, VES by Abem Terrameter and Gas chromatograph - Flame Ionization Detector (GC-FID) for finger-print was employed. The interpreted VES results revealed four geo-electric subsurface layers. The first layer which has a resistivity value of 60Ωm and a thickness of 2.0M was interpreted as top soil. Underlying the first layer is the second layer which had a resistivity value of 122Ωm with a thickness of 3m, interpreted as lateritic sand. The third layer had a resistivity value of 750Ωm and a thickness of 9.0m, and is interpreted as coarse sand. The fourth layer which had a resistivity value of 1255Ωm and a thickness of 49m is interpreted as very coarse sand. Borehole one was used as control and it is 1.85km away from the Resistivity sampling points. The results revealed that the presence of C10-C40 hydrocarbon which indicates un-weathered to fresh hydrocarbon in parts of the study area and heavy metals were below detection limits. The vulnerability of the aquifer to hydrocarbon contamination was due to high permeability, unconsolidated coarse grained and poorly sorted sands, of the vadose zone as well as shallowness of the aquifer. It is recommended that boreholes in the study area should be of deeper depths, and well constructed to avoid contaminated water from the polluted zone entering the borehole through the annulus.


2019 ◽  
Vol 64 (1) ◽  
pp. 55-67
Author(s):  
Vlad Pӑnescu ◽  
◽  
Mihaela Cӑtӑlina Herghelegiu ◽  
Sorin Pop ◽  
Mircea Anton ◽  
...  

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>


2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>


Author(s):  
M. Assad ◽  
V. V. Grushevski ◽  
O. G. Penyazkov ◽  
I. N. Tarasenko

The concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in the gasoline combustion products emitted into the atmosphere by internal combustion engines (ICE) has been measured using the gas chromatography method. The concentrations of PAHs in the exhaust gases sampled behind a catalytic converter has been determined when the ICE operates in five modes: idle mode, high speed mode, load mode, ICE cold start mode (engine warm-up) and transient mode. Using 92 RON, 95 RON and 98 RON gasoline the effect of the octane number of gasoline on the PAHs content in the exhaust gases has been revealed. The concentration of the most carcinogenic component (benzo(α)pyrene) in the exhaust gases behind a catalytic converter significantly exceeds a reference value of benzo(α)pyrene in the atmospheric air established by the WHO and the EU for ICE in the load mode.


Sign in / Sign up

Export Citation Format

Share Document