2,314 research outputs found
Electron Counting Statistics for Non-Additive Environments
Molecular electronics is a rapidly developing field focused on using
molecules as the structural basis for electronic components. It is common in
such devices for the system of interest to couple simultaneously to multiple
environments. Here we consider a model comprised of a double quantum dot (or
molecule) coupled strongly to vibrations and weakly to two electronic leads
held at arbitrary bias voltage. The strong vibrational coupling invalidates
treating the bosonic and electronic environments simply as acting additively,
as would be the case in the weak coupling regime or for flat leads at infinite
bias. Instead, making use of the reaction coordinate framework we incorporate
the dominant vibrational coupling effects within an enlarged system
Hamiltonian. This allows us to derive a non-additive form for the lead
couplings that accounts properly for the influence of strong and non-Markovian
coupling between the double dot system and the vibrations. Applying counting
statistics techniques we track electron flow between the double dot and the
electronic leads, revealing both strong-coupling and non-additive effects in
the electron current, noise and Fano factor.Comment: 16 pages, 6 figures. v2 - close to published versio
Hardcore classification: identifying play styles in social games using network analysis
In the social network of a web-based online game, all players are not equal. Through network analysis, we show that the community of players in a online social game is an example of a scale free small world network and that the growth of the player-base obeys a power law.
The community is centred around a minority group of ``hardcore" players who define the social environment for the game, and without whom the social network would collapse. Methods are discussed for identifying this critically important subset of players automatically through analysing social behaviours within the game
A holistic mathematical modelling and simulation for cathodic delamination mechanism – a novel and an efficient approach
This paper addresses a holistic mathematical design using a novel approach for understanding the mechanism of cathodic delamination. The approach employed a set of interdependent parallel processes with each process representing: cation formation, oxygen reduction and cation transport mechanism, respectively. Novel mathematical equations have been developed for each of the processes based on the observations recorded from experimentation. These equations are then solved using efficient time-iterated algorithms. Each process consists of distinct algorithms which communicate with each other using duplex channels carrying signals. Each signal represents a distinct delamination parameter. As a result of interdependency of various processes and their parallel behaviour, it is much easier to analyse the quantitative agreement between various delamination parameters. The developed modelling approach provides an efficient and reliable prediction method for the delamination failure. The results obtained are in good agreement with the previously reported experimental interpretations and numerical results. This model provides a foundation for the future research within the area of coating failure analysis and prediction
Cubic symmetry and magnetic frustration on the spin lattice in KIrCl
Cubic crystal structure and regular octahedral environment of Ir
render antifluorite-type KIrCl a model fcc antiferromagnet with a
combination of Heisenberg and Kitaev exchange interactions. High-resolution
synchrotron powder diffraction confirms cubic symmetry down to at least 20 K,
with a low-energy rotary mode gradually suppressed upon cooling. Using
thermodynamic and transport measurements, we estimate the activation energy of
eV for charge transport, the antiferromagnetic Curie-Weiss
temperature of K, and the extrapolated saturation
field of T. All these parameters are well reproduced \textit{ab
initio} using eV as the effective Coulomb repulsion
parameter. The antiferromagnetic Kitaev exchange term of K is about
one half of the Heisenberg term K. While this combination removes
a large part of the classical ground-state degeneracy, the selection of the
unique magnetic ground state additionally requires a weak second-neighbor
exchange coupling K. Our results suggest that KIrCl may
offer the best possible cubic conditions for Ir and demonstrates the
interplay of geometrical and exchange frustration in a high-symmetry setting.Comment: 9 page
Synergistic effect of Glomus fasciculatum and Trichoderma pseudokoningii on Heliathus annuus to decontaminate tannery sludge from toxic metals
The effect of two soil amendments of tannery sludge (10% and 20%) on growth and metal uptake of Helianthus annuus L. was studied under three treatments of rhizosphere and mycorrhizal fungi. Trichoderma pseudokoningii Rifai was used as rhizosphere fungal inoculum (F) and Glomus fasciculatum (Thax.) Gerd. & Trappe as the mycorrhizal inoculum (M). The third treatment comprised of combined inoculation (F+M). The control (C) treatment was without any inoculum of the fungi. The plants given both the fungus and mycorrhizal (F+M) treatment showed the maximum growth among all treatments. Plants given only fungus (F) and only mycorrhizal (M) treatment also showed significantly better growth as compared with control (C) treatment. Among the two sludge amendments, the statistical analyses of the results showed increase in all growth parameters in lower (10%) sludge amendment ratio. The accumulation of potentially toxic metals (Cd, Cr, Na and Zn) in different parts of H. annuus grown on tannery sludge amended soil increased with increasing concentration of sludge in the soil. The plants treated with both fungus and mycorrhizal (F+M) treatment showed the maximum uptake of metals and thus the synergistic effect of these fungi can be exploited in decontamination of metals from tannery sludge.Key words: Phytoextraction, tannery sludge, heavy metals, resistant rhizosphere fungi, Arbuscular mycorrhizal fungi
Time Dependent Surface Corrosion Analysis and Modelling of Automotive Steel Under a Simplistic Model of Variations in Environmental Parameters
This research presents time-dependent corrosion analysis of automotive steel utilised in a large military vehicle in real operating environment, followed by simulated environmental tests and simplistic surface corrosion modelling. Time-dependent surface corrosion accumulated on this specific component was observed to be approximately 250 µm thick, with the identification of surface contaminants such as chlorine and sulphur. Simulated environmental tests considering temperature and relative humidity variations were performed to evaluate quantitative corrosion damage to the structure of the vehicle. The relationship of various temperatures and relative humidity with respect to time, within the context of corrosion initiation and propagation, has been presented. A mathematical model to incorporate corrosion accumulation on the surfaces derived from the simulated environmental tests is presented
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