Sequences of Exact Analytical Solutions for Plane-Waves in Graded Media

We present a new method for building sequences of solvable profiles of the electromagnetic (EM) admittance in lossless isotropic materials with 1D graded permittivity and permeability (in particular profiles of the optical refractive-index). These solvable profiles lead to analytical closed-form expressions of the EM fields, for both TE and TM modes. The Property-and-Field Darboux Transformations method, initially developed for heat diffusion modelling, is here transposed to the Maxwell equations in the optical-depth space. Several examples are provided, all stemming from a constant seed-potential, which makes them based on elementary functions only. Solvable profiles of increasingly complex shape can be obtained by iterating the process or by assembling highly flexible canonical profiles. Their implementation for modelling optical devices like matching layers, rugate filters, Bragg gratings, chirped mirrors or 1D photonic crystals, offers an exact and cost-effective alternative to the classical approachesComment: 74 pages, 20 figures, Corrected typos in Annex

Multipurpose S-shaped solvable profiles of the refractive index: application to modeling of antireflection layers and quasi-crystals

A class of four-parameter solvable profiles of the electromagnetic admittance has recently been discovered by applying the newly developed Property & Field Darboux Transformation method (PROFIDT). These profiles are highly flexible. In addition, the related electromagnetic-field solutions are exact, in closed-form and involve only elementary functions. In this paper, we focus on those who are S-shaped and we provide all the tools needed for easy implementation. These analytical bricks can be used for high-level modeling of lightwave propagation in photonic devices presenting a piecewise-sigmoidal refractive-index profile such as, for example, antireflection layers, rugate filters, chirped filters and photonic crystals. For small amplitude of the index modulation, these elementary profiles are very close to a cosine profile. They can therefore be considered as valuable surrogates for computing the scattering properties of components like Bragg filters and reflectors as well. In this paper we present an application for antireflection layers and another for 1D quasicrystals (QC). The proposed S-shaped profiles can be easily manipulated for exploring the optical properties of smooth QC, a class of photonic devices that adds to the classical binary-level QC.Comment: 14 pages, 18 fi

Comment on Photothermal radiometry parametric identifiability theory for reliable and unique nondestructive coating thickness and thermophysical measurements, J. Appl. Phys. 121(9), 095101 (2017)

A recent paper [X. Guo, A. Mandelis, J. Tolev and K. Tang, J. Appl. Phys., 121, 095101 (2017)] intends to demonstrate that from the photothermal radiometry signal obtained on a coated opaque sample in 1D transfer, one should be able to identify separately the following three parameters of the coating: thermal diffusivity, thermal conductivity and thickness. In this comment, it is shown that the three parameters are correlated in the considered experimental arrangement, the identifiability criterion is in error and the thickness inferred therefrom is not trustable.Comment: 3 page

Perceptions of Naturalness in a City Environment

Urban greenspace is vital for cities, for health and well-being benefits to urban dwellers, as well as those spaces providing, potentially, the only link city dwellers have to nature. However, the benefits urban greenspace can provide to people can depend on perceptions of that urban greenspace. Environmental perceptions are highly socially and culturally defined, and therefore subjective. One such important perception, referred to as naturalness, considers how natural people think a landscape is. To determine perceptions of naturalness in an urban environment, this project assessed two contrasting protected areas in Perth, Western Australia; namely Woodman Point Regional Park on the coast, and Mundy Regional Park in the hills. Using an on-site survey method asking participants to indicate perceptions of naturalness and connection to nature on a scale, 403 questionnaires were returned. The respondents identified Woodman Point Regional Park (Md = 5, n = 162) as less natural than Mundy Regional Park (Md = 6, n = 239), although both were still considered natural. Connection to nature was found to be the same between the two parks (Woodman Point Md = 23, n = 162; Mundy Md = 23, n = 236). Several visitor characteristics were found to have relationships with both perceived naturalness and connection to nature, although these relationships are inconclusive. The implications of this research suggest that parks in both urban and peri-urban locations are perceived as natural. Similar perceptions of naturalness of parks in contrasting urban locations may be a result of a lack of public awareness on what is considered ecologically natural. Despite this, urban greenspace still provides personal benefit. Outcomes of this project not only demonstrate the importance to people of large natural areas in cities for providing connections to nature that otherwise may be lost, but also raises awareness and knowledge of nature, that may also otherwise be lost to the population

The Sech(Xi)-type profiles: a Swiss-Army knife for exact analytical modelling of thermal diffusion and wave propagation in graded media

This work deals with exact analytical modelling of transfer phenomena in heterogeneous materials exhibiting one-dimensional continuous variations of their properties. Regarding heat transfer, it has recently been shown that by applying a Liouville transformation and multiple Darboux transformations, infinite sequences of solvable profiles of thermal effusivity can be constructed together with the associated temperature (exact) solutions, all in closed-form expressions (vs. the diffusion-time variable and with a growing number of parameters). In addition, a particular class of profiles, so-called sech(xi)-type profiles, exhibit high agility and in the same time parsimony. In this paper we go further into the description of these solvable profiles and their properties. Most importantly, their quadrupole formulation is provided which allows building smooth synthetic profiles of effusivity of arbitrary complexity and thereafter getting very easily the corresponding temperature dynamic response. Examples are given with increasing variability of effusivity and increasing number of elementary profiles. These highly flexible profiles are equally relevant for providing an exact analytical solution to wave propagation problems in 1D graded media (i.e. Maxwell's equations, acoustic equation, telegraph equation...). From now on, let it be for diffusion-like or wave-like problems, when the leading properties present (possibly piecewise-) continuously heterogeneous profiles, the classical staircase model can be advantageously replaced by a "high-level" quadrupole model consisting of one or more sech(xi)-type profiles, which makes the latter a true Swiss-Army knife for analytical modelling.Comment: 21 pages; 7 figure

The Development of eHealth in an Enlarged EU: Synthesis Report

In 2005, IPTS launched a project which aimed to assess the developments in eGoverment, eHealth and eLearning in the 10 New Member States at national, and cross-country level. At that time, the 10 New Member States were Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovenia and Slovakia. A report for each country was produced, describing its government and health systems and the role played by eGovernment and eHealth within these systems. Each report then analyzes, on the basis of desk research and expert interviews, the major achievements, shortcomings, drivers and barriers in the development of eGovernment and eHealth in one of the countries in question. This analysis provides the basis for the identification and discussion of national policy options to address the major challenges and to suggest R&D issues relevant to the needs of each country. In addition to national monographs, the project has delivered three synthesis reports, which offers an integrated view of the developments of each application domain in the New Member States. This report gives a comparative assessment of eHealth policies and institutions, problems and achievements with eHealth in the EU10. It also shows the examples of best practices with in eHealth developments, analyses the possible policy options at local, regional, national and European levels and highlights the most important future technical and non-technical R&D challenges specific to eHealth. Furthermore, a prospective report looking across and beyond the development of the eGoverment, eHealth and eLearning areas has been developed to summarize policy challenges and options for the development of eServices and the Information Society towards the goals of Lisbon and i2010.JRC.J.4-Information Societ

Development and validation of a numerical tool for the simulation of the temperature field and infrared radiance rendering in an urban scene

International audienceWe present a numerical tool aimed at simulating infrared images of an urban environment, by solving the direct heat transfer problem, and then computing the radiance rendering at the sensor level. SOLENE (Cerma, Nantes) was coupled with two software packages developed at ONERA: SUSHI (Simulation in Urban Scene of Heat dIffusion) and MOHICANS (MOdélisation Hyperspectrale d'Images en entrée Capteur pour l'ANalyse et l'inversion du Signal) for realizing this task. SUSHI is also used for computing the surface temperatures: either a 1D model or a 2D model is used. We present the whole software chain, its validation by software and experimental analysis

The Development of eServices in an Enlarged EU: A Synthesis Report on eLearning

In 2005, IPTS launched a project which aimed to assess the developments in eGoverment, eHealth and eLearning in the 10 New Member States at national, and at cross-country level. At that time, the 10 New Member States were Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovenia and Slovakia. A report for each country was produced, describing its educational system and the role played by eLearning within both the formal education system and other aspects of lifelong learning. Each report then analyzed, on the basis of desk research and expert interviews, the major achievements, shortcomings, drivers and barriers in the development of eLearning in one of the countries in question. This synthesis report developed in the final phases of the project offers an integrated view of the developments of eLearning in the New Member States. Furthermore, the project has prepared a prospective report looking across and beyond the development of the eGoverment, eHealth and eLearning areas to summarize policy challenges and options for the development of eServices and the Information Society towards the goals of Lisbon and i2010.JRC.J.4-Information Societ

Ligand-Induced Incompatible Curvatures Control Ultrathin Nanoplatelet Polymorphism and Chirality

The ability of thin materials to shape-shift is a common occurrence that leads to dynamic pattern formation and function in natural and man-made structures. However, harnessing this concept to design inorganic structures at the nanoscale rationally has remained far from reach due to a lack of fundamental understanding of the essential physical components. Here, we show that the interaction between organic ligands and the nanocrystal surface is responsible for the full range of chiral shapes seen in colloidal nanoplatelets. The adsorption of ligands results in incompatible curvatures on the top and bottom surfaces of NPL, causing them to deform into helico\"ids, helical ribbons, or tubes depending on the lateral dimensions and crystallographic orientation of the NPL. We demonstrate that nanoplatelets belong to the broad class of geometrically frustrated assemblies and exhibit one of their hallmark features: a transition between helico\"ids and helical ribbons at a critical width. The effective curvature $\bar{\kappa}$ is the single aggregate parameter that encodes the details of the ligand/surface interaction, determining the nanoplatelets' geometry for a given width and crystallographic orientation. The conceptual framework described here will aid the rational design of dynamic, chiral nanostructures with high fundamental and practical relevance.Comment: 16 pages, 8 figure