Three-dimensional rogue waves in non-stationary parabolic potentials

Using symmetry analysis we systematically present a higher-dimensional similarity transformation reducing the (3+1)-dimensional inhomogeneous nonlinear Schrodinger (NLS) equation with variable coefficients and parabolic potential to the (1+1)-dimensional NLS equation with constant coefficients. This transformation allows us to relate certain class of localized exact solutions of the (3+1)-dimensional case to the variety of solutions of integrable NLS equation of (1+1)-dimensional case. As an example, we illustrated our technique using two lowest order rational solutions of the NLS equation as seeding functions to obtain rogue wave-like solutions localized in three dimensions that have complicated evolution in time including interactions between two time-dependent rogue wave solutions. The obtained three-dimensional rogue wave-like solutions may raise the possibility of relative experiments and potential applications in nonlinear optics and BECs.Comment: 7 pages, 6 figure

Projected-Dipole Model for Quantum Plasmonics

Quantum effects of plasmonic phenomena have been explored through ab-initio studies, but only for exceedingly small metallic nanostructures, leaving most experimentally relevant structures too large to handle. We propose instead an effective description with the computationally appealing features of classical electrodynamics, while quantum properties are described accurately through an infinitely thin layer of dipoles oriented normally to the metal surface. The nonlocal polarizability of the dipole layer is mapped from the free-electron distribution near the metal surface as obtained with 1D quantum calculations, such as time-dependent density-functional theory (TDDFT), and is determined once and for all. The model can be applied to any system size that is tractable within classical electrodynamics, while capturing quantum plasmonic aspects of nonlocal response and a finite work function with TDDFT-level accuracy. Applying the theory to dimers we find quantum-corrections to the hybridization even in mesoscopic dimers as long as the gap is sub-nanometric itself.Comment: Supplemental Material is available upon request to author

Collisionless relaxation in non-neutral plasmas

A theoretical framework is presented which allows to quantitatively predict the final stationary state achieved by a non-neutral plasma during a process of collisionless relaxation. As a specific application, the theory is used to study relaxation of charged-particles beams. It is shown that a fully matched beam relaxes to the Lynden-Bell distribution. However, when a mismatch is present and the beam oscillates, parametric resonances lead to a core-halo phase separation. The approach developed accounts for both the density and the velocity distributions in the final stationary state.Comment: Accepted in Phys. Rev. Let

Elimination of IR/UV via Gravity in Noncommutative Field Theory

Models of particle physics with Noncommutative Geometry (NCG) generally suffer from a manifestly non-Wilsonian coupling of infrared and ultraviolet degrees of freedom known as the "IR/UV Problem" which would tend to compromise their phenomenological relevance. In this Letter we explicitly show how one may remedy this by coupling NCG to gravity. In the simplest scenario the Lagrangian gets multiplied by a nonconstant background metric; in $\phi-4$ theory the theorem that $\int d^4 x \phi \star \phi = \int d^4 x \phi^2$ is no longer true and the field propagator gets modified by a factor which depends on both NCG and the variation of the metric. A suitable limit of this factor as the propagating momentum gets asymptotically large then eradicates the IR/UV problem. With gravity and NCG coupled to each other, one might expect anti-symmetric components to arise in the metric. Cosmological implications of such are subsequently discussed.Comment: 6 pages; MPLA versio

Characterizing Uncertainty in Air Pollution Damage Estimates

This study uses Monte Carlo methods to characterize the uncertainty associated with per-ton damage estimates for 100 power plants in the contiguous United States (U.S.) This analysis focuses on damage estimates produced by an Integrated Assessment Model (IAM) for emissions of two local air pollutants: sulfur dioxide (SO2) and .ne particulate matter (PM2:5). For each power plant, the Monte Carlo procedure yields an empirical distribution for the damage per ton of SO2 and PM2:5:For a power plant in New York, one ton of SO2 produces $5,160 in damages with a 90$1,000 and $14,090. A ton of PM2:5 emitted from the same facility causes$17,790 worth of damages with a 90% percentile interval of $3,780 and$47,930. Results for the sample of 100 fossil-fuel .red power plants shows a strong spatial pattern in the marginal damage distributions. The degree of variability increases by plant location from east to west. This result highlights the importance of capturing uncertainty in air quality modeling in the empirical marginal damage distributions. Further, by isolating uncertainty at each module in the IAM we .nd that uncertainty associated with the dose-response parameter, which captures the in.uence of exposure to PM2:5 on adult mortality rates, the mortality valuation parameter, and the air quality model exert the greatest in.uence on cumulative uncertainty. The paper also demonstrates how the marginal damage distributions may be used to guide regulators in the design of more efficient market-based air pollution policy in the U.S.Monte Carlo, Air Pollution, Market-based Pollution Policy

Liquid-state theory of charged colloids

A simple theory of the fluid state of a charged colloidal suspension is proposed. The full free energy of a polyelectrolyte solution is calculated. It is found that the counterions condense onto the polyions forming clusters composed of one polyion and n counterions. The distribution of cluster sizes is determined explicitly. In agreement with the current experimental and Monte Carlo results, no liquid-gas phase separation was encountered.Comment: 4 pages, 2 Postscript figures, uses multicol.sty; changed conten

Numerical modelling and condition assessment of timber utility poles using stress wave techniques

University of Technology Sydney. Faculty of Engineering and Information Technology.Timber utility poles are traditionally used for electricity and telecommunication distribution and represent a significant part of the infrastructure for electricity distribution and communication networks in Australia and New Zealand. Nearly 7 million timber poles are in service and about $40-$50 million is spent annually on their maintenance and asset management. To prevent the ageing poles from collapse, about 300,000 electricity poles are replaced in the Eastern States of Australia every year. However, up to 80% of the replaced poles are still in a very good condition (Nguyen et al., 2004). Therefore, huge natural resources and money is wasted. Accordingly, a reliable non-destructive evaluation technique is essential for the condition assessment of timber poles/piles to ensure public safety, operational efficiency and to reduce the maintenance cost. Several non-destructive testing (NDT) methods based on stress wave propagation have been used in practice for the condition assessment of timber poles. However, stress wave propagation in timber poles especially with the effect of soil embedment coupled with unknown pole conditions below ground line (such as deterioration, moisture etc.) is complicated, and therefore it hindered the successful application of these NDT methods for damage identification of timber poles. Moreover, some stress wave based NDT methods are often based on over-simplified assumptions and thus fail to deliver reliable results. In the presented study, in order to gain an in-depth understanding of the propagation of stress waves in damaged poles and to develop an effective damage detection method, a solid numerical study of wave behaviour is undertaken and novel wavelet packet energy (WPE) method is investigated for damage identification. Numerical studies utilises finite element (FE) models to track the wave propagation behaviour characteristics considering different boundary conditions, material properties as well as impact and sensing locations. WPE is a sensitive indicator for structural damage and has been used for damage detection in various types of structures. This thesis presents a comprehensive investigation on the novel use of WPE for damage identification in timber utility poles using FE models. The research study comprises several aspects of investigations such as a comparative study between 2D and 3D models, a sensitivity study of mesh density for 2D models, and a study of the novel WPE-based technique for damage classification and detection in timber poles. Support vector machine (SVM) is imported for damage classification and particle swarm optimisation (PSO) is selected to achieve the classification. The results clearly show the effectiveness of the proposed novel WPE based damage identification technique. Damage prediction based on optimisation procedure is also carried out in this thesis. Several numerical models with different damage conditions are created and the damage size is predicted according to optimisation procedure based on information from sample damaged model. Genetic algorithm and artificial fish swarm algorithm are used as optimisation algorithms and the comparative study is conducted based on the prediction results. The influence of damage on the strength of timber utility poles is also studied in this thesis. The damage conditions are changes in diameter, length as well as location. Wind is considered as a main reason to cause the collapse of timber utility poles in this research. Wind load is defined based on Australian standards and the Ausgrid manual, and the corresponding stress is calculated through FE analysis. According to this analysis, it can be found that under specific damage conditions, some small damage may cause collapse; however, for certain conditions, the timber poles can still be safe even when large damage exists. In conclusion, a novel WPE based damage detection method has been successfully developed to address the limitations of existing methods for condition assessment of timber utility poles. The numerical verification has shown the method is effective for identification of the classification and severity of damage

Donnan equilibrium and the osmotic pressure of charged colloidal lattices

We consider a system composed of a monodisperse charge-stabilized colloidal suspension in the presence of monovalent salt, separated from the pure electrolyte by a semipermeable membrane, which allows the crossing of solvent, counterions, and salt particles, but prevents the passage of polyions. The colloidal suspension, that is in a crystalline phase, is considered using a spherical Wigner-Seitz cell. After the Donnan equilibrium is achieved, there will be a difference in pressure between the two sides of the membrane. Using the functional density theory, we obtained the expression for the osmotic pressure as a function of the concentration of added salt, the colloidal volume fraction, and the size and charge of the colloidal particles. The results are compared with the experimental measurements for ordered polystyrene lattices of two different particle sizes over a range of ionic strengths and colloidal volume fractions.Comment: 8 pages, 4 Postscript figures, uses multicol.sty, to be published in European Physical Journal