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Structural color is poorly known in plants relative to animals. In fruits, only a handful of cases have been described, including in Viburnum tinus where the blue color results from a disordered multilayered reflector made of lipid droplets. Here, we examine the broader evolutionary context of fruit structural color across the genus Viburnum. We obtained fresh and herbarium fruit material from 30 Viburnum species spanning the phylogeny and used transmission electron microscopy, optical simulations, and ancestral state reconstruction to identify the presence/absence of photonic structures in each species, understand the mechanism producing structural color in newly identified species, relate the development of cell wall structure to reflectance in Viburnum dentatum, and describe the evolution of cell wall architecture across Viburnum. We identify at least two (possibly three) origins of blue fruit color in Viburnum in species which produce large photonic structures made of lipid droplets embedded in the cell wall and which reflect blue light. Examining the full spectrum of mechanisms producing color in pl, including structural color as well as pigments, will yield further insights into the diversity, ecology, and evolution of fruit color.

To manipulate the light-matter interaction effectively, we often rely on high refractive index inorganic nanoparticles. Such materials are contained essentially in everything that looks colorful or white: from paints to coatings but also in processed food, toothpaste, and cosmetic products. As these nanoparticles can accumulate in the human body and environment, there is a strong need to replace them with more biocompatible counterparts. In this work, we introduce various types of cellulose-based microparticles (CMPs) of four sizes with optimized dimensions for efficient light scattering that can replace traditional inorganic particles. We demonstrate that the produced materials can be exploited as highly efficient scattering enhancers, with designed optical performance. Finally, exploiting these cellulose colloids, we fabricated scattering materials and high transmittance/haze films with record performances with respect to the state-of-the-art values. The renewable and biocompatible nature of our systems, combined with their excellent optical properties, allows for the use of our cellulose-based particles in paints, LEDs, and solar cell devices and especially in applications where the biocompatibility of the component is essential, such as in food and pharmaceutical coatings.

Strong-coupling between excitons and confined photonic modes can lead to the formation of new quasi-particles termed exciton-polaritons which can display a range of interesting properties such as super-fluidity, ultrafast transport and Bose-Einstein condensation. Strong-coupling typically occurs when an excitonic material is confided in a dielectric or plasmonic microcavity. Here, we show polaritons can form at room temperature in a range of chemically diverse, organic semiconductor thin films, despite the absence of an external cavity. We find evidence of strong light-matter coupling via angle-dependent peak splittings in the reflectivity spectra of the materials and emission from collective polariton states. We additionally show exciton-polaritons are the primary photoexcitation in these organic materials by directly imaging their ultrafast (5 × 106 m s−1), ultralong (~270 nm) transport. These results open-up new fundamental physics and could enable a new generation of organic optoelectronic and light harvesting devices based on cavity-free exciton-polaritons, Exciton-polaritons are typically formed in organic systems when the molecules are confined between metallic or dielectric mirrors. Here, the authors reveal that interactions between excitons and moderately confined photonic states within the bare organic film can also lead to polariton formation, making them the primary photoexcitation.

The race to heuristically solve non-deterministic polynomial-time (NP) problems through efficient methods is ongoing. Recently, optics was demonstrated as a promising tool to find the ground state of a spin-glass Ising Hamiltonian, which represents an archetypal NP problem. However, achieving completely programmable spin couplings in these large-scale optical Ising simulators remains an open challenge. Here, by exploiting the knowledge of the transmission matrix of a random medium, we experimentally demonstrate the possibility of controlling the couplings of a fully connected Ising spin system. By further tailoring the input wavefront we showcase the possibility of modifying the Ising Hamiltonian both by accounting for an external magnetic field and by controlling the number of degenerate ground states and their properties and probabilities. Our results represent a relevant step toward the realisation of fully-programmable Ising machines on thin optical platforms, capable of solving complex spin-glass Hamiltonians on a large scale., 13 pages, 9 figures

Colours in natural systems, e.g. bird feathers, butterfly wings or the peacock, are often created by scattering of nanostructured materials, rather than the common absorption mechanism of dyes. Bacterial colonies of Flavobacterium strain IR1 were discovered to possess incredibly bright structural colouration [1] . The 2D hexagonal crystalline arrangement of the cells is found to be a distinctive fingerprint of the colony organisation [2] . By combining analytical analysis of the angle-resolved scattering response of in-vivo bacterial colonies with numerical modelling, we show that we can access to the inter-cells distance and cell diameter with a resolution below 10 nm, far better than what can be achieved with conventional electron microscopy, suffering from preparation artefacts. Retrieving the role of disorder at different length scales from the salient features in the scattering spectra enables to obtain a precise understanding of the structural organisation of the bacteria in three dimensions and to gather insights into their metabolism relevant for inter-cellular communication. These measurements of intercellular distances within Flavobacterium colonies enable to study the physical interactions of cells during adaptation of the colony structure to environmental conditions, such as nutrient content and allows the use of their structural colour for biosensing applications.

Scattering enhancers are a class of nanomaterials used in every colored or white material surrounding us: from paints and inks to food and cosmetics to packaging and paper. Such hiding pigments usually consist of non-absorbing, high refractive index nanoparticles, for example spherically shaped titanium dioxide nanopowders. However use of TiO2 carries a high environmental burden. To offset the carbon footprint and health concerns inherent with the use of titanium dioxide, one could approach the challenge of scattering optimization by modifying the morphology of the scattering elements rather than their refractive index. Here, inspired by the bright anisotropic scattering system found in nature, we demonstrate that anisotropic sphero-cylindrical particles can outperform the scattering efficiency of their isotropic counterparts – obtaining an excellent scattering performances across the visible electromagnetic spectrum. We developed a class of micron-sized scattering enhancers composed only of silica. We show that these cylindrical colloids are easily assembled into scattering supracolloidal balls, a new class of pigment microspheres which can be used in formulations for ultrabright coatings.

International audience; 16 Viburnum tinus is an evergreen shrub that is native to the Mediterranean region but cultivated 17 widely in Europe and around the world. It produces ripe metallic blue fruits throughout winter [1]. 18 Despite its limited fleshy pulp,[2] its high lipid content[3] makes it a valuable resource to the small 19 birds[4] that act as its seed-dispersers[5]. Here, we find that the metallic blue appearance of the 20 fruits is produced by globular lipid inclusions arranged in a disordered multilayer structure. This 21 structure is embedded in the cell walls of the epicarp and underlaid with a dark layer of anthocyanin 22 pigments. The presence of such large, organised lipid aggregates in plant cell walls represents a new 23 mechanism for structural colouration and may serve as an honest signal of nutritional content. 24 Results and Discussion 25 The colours of fleshy fruits are thought to serve primarily to attract animal dispersers, and 26 understanding the origins and diversity of fleshy fruit colours provides insight into the ecological 27 interactions between plants and their dispersers.[7] Viburnum tinus (Adoxaceae) is a shrub native to 28 the Mediterranean region that is now cultivated around the world.[8] It produces large numbers of 29 metallic blue fruits throughout the year. Although a variety of bird dispersers consume V. tinus 30 fruits,[2] these serve as an especially important food source for birds during winter, including the 31 Eurasian blackcap (Sylvia atricapilla)[9] and the European robin (Erithacus rubecola).[10] While the 32 remarkable blue metallic appearance of V. tinus fruits (Figure 1) is commonly known and previously 33 reported,[11] the mechanism by which such blue colour is produced has not been elucidated. In a 34 review of earlier literature,[12] the colour of V. tinus has been attributed to the presence of 35 anthocyanin pigments. 36

Living organisms have developed a wide range of appearances from iridescent to matte textures. Interestingly, angular independent structural colors, where isotropy in the scattering structure is present, only produce coloration in the blue wavelength region of the visible spectrum. One might, therefore, wonder if such observation is a limitation of the architecture of the palette of materials available in nature. Here, by exploiting numerical modeling, we discuss the origin of isotropic structural colors without restriction to a specific light scattering regime. We show that high color purity and color saturation cannot be reached in isotropic short-range order structures for red hues. This conclusion holds even in the case of advanced scatterer morphologies, such as core-shell particles or inverse photonic glasses — explaining recent experimental findings reporting very poor performances of visual appearance for such systems.

Plants have various strategies to protect themselves from harmful light. An example of such a protective mechanism is the growth of epicuticular nanostructures, such as a layer of hair or wax crystals. Most nanostructures are optimised to screen UV radiation, as UV light is particularly damaging for cellular tissue. We find that, contrary to the commonly found UV reflectance, the epicuticular wax crystals on Tradescantia leaves reflect strongly in the higher visible wavelength regime. Thus, they give the leaves a golden shine. We characterize the optical appearance of Tradescantia pallida 'purpurea' leaves by angularly resolved spectroscopy and compare the results to finite difference time domain simulations. We find that it is the disordered assembly of the wax platelets that is the crucial parameter to obtain the observed reflected intensity increase for higher wavelengths.

Vivid colours found in living organisms are often the result of scattering from hierarchical nanostructures, where the interplay between order and disorder in their packing defines visual appearance. In the case of Flavobacterium IR1, the complex arrangement of the cells in polycrystalline three-dimensional lattices is found to be a distinctive fingerprint of colony organization. By combining analytical analysis of the angle-resolved scattering response of in vivo bacterial colonies with numerical modelling, we show that we can assess the inter-cell distance and cell diameter with a resolution below 10 nm, far better than what can be achieved with conventional electron microscopy, suffering from preparation artefacts. Retrieving the role of disorder at different length scales from the salient features in the scattering response enables a precise understanding of the structural organization of the bacteria. © 2020 The Author(s) Published by the Royal Society. All rights reserved.

Corals have evolved as optimized photon augmentation systems, leading to space-efficient microalgal growth and outstanding photosynthetic quantum efficiencies. Light attenuation due to algal self-shading is a key limiting factor for the upscaling of microalgal cultivation. Coral-inspired light management systems could overcome this limitation and facilitate scalable bioenergy and bioproduct generation. Here, we develop 3D printed bionic corals capable of growing microalgae with high spatial cell densities of up to 109 cells mL−1. The hybrid photosynthetic biomaterials are produced with a 3D bioprinting platform which mimics morphological features of living coral tissue and the underlying skeleton with micron resolution, including their optical and mechanical properties. The programmable synthetic microenvironment thus allows for replicating both structural and functional traits of the coral-algal symbiosis. Our work defines a class of bionic materials that is capable of interacting with living organisms and can be exploited for applied coral reef research and photobioreactor design., Corals have evolved as finely tuned light collectors. Here, the authors report on the 3D printing of coral-inspired biomaterials, that mimic the coral-algal symbiosis; these bionic corals lead to dense microalgal growth and can find applications in algal biotechnology and applied coral science.

Photonic materials with angular independent structural colour are highly desirable because they offer the broad viewing angles required for application as colorants in paints, cosmetics, textiles or displays. However, they are challenging to fabricate as they require isotropic nanoscale architectures with only short-range correlation. In this article, porous microparticles with such a structure are produced in a single, scalable step from an amphiphilic bottlebrush block copolymer. This is achieved by exploiting a novel controlled micellization self-assembly mechanism within emulsified toluene-in-water droplets. By restricting water permeation through the droplet interface, the size of the pores can be precisely addressed, resulting in structurally coloured pigments. Furthermore, the reflected colour can be tuned to reflect across the full visible spectrum using only a single polymer (Mn = 290 kDa) by altering the initial emulsification conditions. Such photonic pigments have several key advantages over their crystalline analogues, as they provide isotropic structural coloration that suppresses iridescence and improves colour purity without the need for either refractive index matching or the inclusion of a broadband absorber., 32 pages, 18 figures, 1 table

Hydroxypropyl cellulose (HPC) is a biocompatible cellulose derivative capable of self assembling into a lyotropic chiral nematic phase in aqueous solution. This liquid crystalline phase reflects right-handed circular polarized light of a specific color as a function of the HPC weight fraction. Here, we demonstrate that, by introducing a crosslinking agent, it is possible to drastically alter the visual appearance of the HPC mesophase in terms of the reflected color, the scattering distribution and the polarization response, resulting in an exceptional matte appearance in dry solid-state films. By exploiting the interplay between order and disorder, a robust and simple methodology towards the preparation of polarization and angular independent color was developed, which constitutes an important step towards the development of real-world photonic colorants., This work is funded by EPSRC grant EP/R511675/1 to B.F.-P., S.V.; by EPSRC grant EP/L016087/1 to C.A.W.; by BBSRC David Phillips fellowship BB/K014617/1 to G.J., S.V.; by EU’s Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No. 722842 (ITN Plant-inspired Materials and Surfaces – PlaMatSu) to G.T.K., S.V.; by Swiss National Science Foundation #165176 to R.V.; by Croucher Cambridge International Scholarship to C.L.C.C.; by ERC grant ERC 2014 STG H2020 639088 to M.M.B., G.J., S.V.; by ERC grant ERC 2017 POC 790518 to R.M.P., S.V.

Both vertebrates and invertebrates commonly exploit photonic structures adjacent to their photoreceptors for visual benefits. For example, use of a reflecting structure (tapetum) behind the retina increases photon capture, enhancing vision in dim light [1–5]. Colored filters positioned lateral or distal to a photoreceptive unit may also be used to tune spectral sensitivity by selective transmission of wavelengths not absorbed or scattered by the filters [6–8]. Here we describe a new category of biological optical filter that acts simultaneously as both a transmissive spectral filter and narrowband reflector. Discovered in the larval eyes of only one family of mantis shrimp (stomatopod) crustaceans (Nannosquillidae), each crystalline structure bisects the photoreceptive rhabdom into two tiers and contains an ordered array of membrane-bound vesicles with sub-wavelength diameters of 153 ± 5 nm. Axial illumination of the intrarhabdomal structural reflector (ISR) in vivo produces a narrow band of yellow reflectance (mean peak reflectivity, 572 ± 18 nm). The ISR is similar to several synthetic devices, such as bandgap filters, laser mirrors, and (in particular) fiber Bragg gratings used in optical sensors for a wide range of industries. To our knowledge, the stomatopod larval ISR is the first example of a naturally occurring analog to these human-made devices. Considering what is known about these animals’ visual ecology, we propose that these reflecting filters may help improve the detection of pelagic bioluminescence in shallow water at night. Video Abstract: Feller et al. report how one family of mantis shrimp larvae uses visual filtering structures to selectively reflect and transmit light within photoreceptors. These reflective filters likely enhance bioluminescence detection underwater at night and are similar to human-made optical devices such as fiber Bragg gratings or band gap filters.

The scattering strength of a random medium relies on the geometry and spatial distribution of its components as well as on their refractive index. Anisotropy can, therefore, play a major role in the optimization of the scattering efficiency in both biological and synthetic materials. In this study, we show that, by exploiting the coherent backscattering phenomenon, it is possible to characterize the optical anisotropy in Cyphochilus beetle scales without the need to change their orientation or their thickness. For this reason, such a static and easily accessible experimental approach is particularly suitable for the study of biological specimens. Moreover, estimation of the anisotropy in Cyphochilus beetle scales might provide inspiration for improving the scattering strength of artificial white materials.

International audience; Pachyrhynchus sarcitis weevils are flightless weevils characterized by colored patches of scales on their dark elytra. The vivid colors of such patches result from the reflection of differently oriented 3D photonic crystals within their scales. The results show that hybrid P. sarcitis, the first filial generation oftwo P. sarcitis populations from Lanyu Island (Taiwan) and Babuyan Island (Philippines), mixes the color of its ancestors by tuning the photonic structure in its scales. A careful spectroscopical and anatomical analysis of the weevils in the phylogeny reveals the hereditary characteristics of the photonic crystals within their scales in terms of lattice constant, orientation and domain size. Monitoring how structural coloration is inherited by offspring highlights the versatility of photonic structures to completely redesign the optical response of living organisms. Such finding sheds light onto the evolution and development mechanisms of structural coloration in Pachyrhynchus weevils and provides inspiration for the design of visual appearance in artificial photonic materials.

The understanding of the interaction between light and complex, random structures is the key for designing and tailoring the optical appearance and performance of many materials that surround us, ranging from everyday consumer products, such as those for personal care, paints, and paper, to light diffusers used in the LED-lamps and solar cells. Here, it is demonstrated that the light transport in membranes of pure cellulose nanofibrils (CNFs) can be controlled to achieve bright whiteness in structures only a few micrometers thick. This is in contrast to other materials, such as paper, which require hundreds of micrometers to achieve a comparable appearance. The diffusion of light in the CNF membranes is shown to become anomalous by tuning the porosity and morphological features. Considering also their strong mechanical properties and biocompatibility, such white coatings are proposed as a new application for cellulose nanofibrils.

Erratum to: A.B. Baskin et al. (Eds.) Cooperative Knowledge Processing for Engineering Design DOI: 10.1007/978-0-387-35357-9

Information in the area of developing transportable decision support systems (DSSs) (agricultural or otherwise) has been scarce. Therefore, developers of DSSs have had some difficulties in constructing DSSs which could be widely used. In the first part of this two-part paper series, a conceptual framework was introduced which proposes methods for making DSSs transportable. This framework serves as a checklist and includes recommendations about general implementation, user interaction, data management, and model aspects. To illustrate the implementation of these recommendations, the development of a DSS within a project called SYBIL is discussed in detail. Therein, portable and public domain tools have been used to build the DSS with a graphical user interface (GUI) which satisfies the general implementation aspects of the framework. Further, the development of a flexible data management system has been essential in the project so that different types of data can be easily handled without changing the models. In order to allow models embedded within the DSS to be successfully transported between regions, a novel artificial intelligence (AI) adaptation methodology was implemented. The main component of this adaptation methodology is a genetic algorithm (GA), an AI search technique. By linking a GA to an agricultural model, the model becomes more robust because the model is able to adapt to the region in which it is being used. Overall, by using the framework criteria to select/create these tools/components, the DSS has been made easy to transport and disseminate.

Developers of agricultural decision support systems (DSSs) have had little guidance in constructing DSSs which could be widely used. To assist, a conceptual framework is introduced which proposes methods for making DSSs transportable so that their utility is high. This framework serves as a checklist and includes recommendations about general implementation, user interaction, data management, and models. General implementation aspects emphasize portable and public domain tools, and user interaction aspects the use of a graphical user interface (GUI); flexible data management systems play a large role in satisfying the suggested data management aspects; and an intelligent model adaptation strategy is one of the main model aspect recommendations.

An AI adaptation methodology designed to assist in transporting agricultural models between regions is presented. Models frequently need adaptation when transported because models developed in one region often do not produce valid results when used in a different region. The methodology prescribes the linkage of a genetic algorithm to a model. This makes the model more robust because it is able to adapt to the region in which it is being used. This methodology has been implemented within a DSS, and preliminary testing indicates this methodology has the ability to allow agricultural models developed in one area to be effectively utilized in other regions.

HYDRA is a DSS to improve irrigation water use efficiency in Mediterranean agriculture, helping consortia or regional authorities determine water requirements and supporting local irrigation decision making. HYDRA, in addition to soil-water and crop-growth simulation models, database, GIS, and GUI, contains expert systems to control decision scenarios and handle missing or erroneous data. Expert systems coupled to the other components serves as a crisp framework in which to organize intelligent DSS and simulation models for adaptability and portability, alleviating problems arising from sensitivity of the models to assumptions specific to geographic location in which they were developed. HYDRA is portable to multiple platforms (workstation and PC) and operating in many different locations in Europe.

Finite-element methods have been applied for the spreading process of a ceramic liquid droplet impacting on a flat cold surface under plasma spraying conditions. The goals of the present investigation are to predict the geometrical form of the splat as a function of process parameters, such as initial temperature and velocity, and to follow the thermal field developing in the droplet up to solidification. A nonlinear finite-element procedure has been extended to model the complex physical phenomena involved in the impact process. The dynamic motion of the viscous melt in the drops as constrained by elastic surface tensions and in interaction with the developing contact with the target has been coupled to transient thermal phenomena to account for the solidification of the material. A model is used to study the impact of spherical particles of liquid ceramic of given temperature and velocity on a flat, cool rigid surface. The deformation of the splat geometry as well as the evolution of the thermal field within the splat are followed up to the final state and require adaptive discretization techniques. The proposed model can be used to correlate flattening degrees with the initial process parameters.

Finite element simulation techniques have been applied to the spreading process of single ceramic liquid droplets impacting on a flat cold surface under plasma-spraying conditions. The goal of the present investigation is to predict the geometrical form of the splat as a function of technological process parameters, such as initial temperature and velocity, and to follow the thermal field developing in the droplet up to solidification. A non-linear finite element programming system has been utilized in order to model the complex physical phenomena involved in the present impact process. The Lagrangean description of the motion of the viscous melt in the drops, as constrained by surface tension and the developing contact with the target, has been coupled to an analysis of transient thermal phenomena accounting also for the solidification of the material. The present study refers to a parameter spectrum as from experimental data of technological relevance. The significance of process parameters for the most pronounced physical phenomena is discussed as are also the consequences of modelling. We consider the issue of solidification as well and touch on the effect of partially unmelted material.

Designing enterprise architectures for accountability is to reason about options. Instead of taking enterprise architectures as products, the paper seeks to comprehend how they are produced. Considering enterprise architecture as an entangled category of sociological, political and democratic challenges provide an opportunity to determine the political topos of enterprise architectures.

Small Medium Enterprises (SMEs) face specific challenges as the pace of technological advancement quickens. In order to keep pace with market demands, these SMEs need, among others, new tools to manage information content and new problem solving skills. They also need personnel capable to analyse the new tools and methodologies, select the most appropriate, deploy the solutions and train their workforce. Larger corporations can relay on the presence of various skills within the company to create successful teams; they can afford external consultants to assist the change management, and broadly based training programs, while SMEs cannot.

The paper reports on fieldwork concerning destination management: the build up of a virtual organisation for a tourist destination, the choice of a destination marketing strategy, the creation of a destination management system. The work belongs to the research domain on Information Systems, involving IT aspects as well as aspects of people development, organisation and management, and of marketing and business. The solid structure of an enterprise organisation is here replaced by the weak-link structure of a local community. The character of the present work is that of a case study, and the research methodology employed follows the guidelines of Action Research [1] [7]. In some respects, it is akin to Participatory Design in the field of software development. The present work builds up on earlier research work on destination management and destination management systems in the ICT community [3] [4] [11] [18] [20]. The point of view here focuses on tourist destinations (TDs), intended as homogeneous territorial domains, identifiable each with its own name, personality, and offer of a tourist product. We have helped a small TD to get started in adapting to the new situation and to induce change, and we trained ourselves on how to help to induce change successfully.

In our paper we discuss a system which takes advantage of the possibilities of object oriented software design and implementation on the one hand and it assists the users in using the same pieces of software several times on the other hand. This is the so called software reuse, which is applied not only to the code and executable parts of software, but to all results appearing during the life-cycle of a software product. A multi-user system is with persistent knowledge about all aspects of the software to be implemented during its life-cycle. The persistent knowledge of object repositories is used y possibly different users having a web of shared understanding to result in collaborative problem solving.

The FABERCOAT Decision Support System (DSS) is a design tool for the production of plasma-sprayed coatings developed in a CEC project among European universities, laboratories and manufacturing industries. The FABERCOAT system utilises a genetic algorithm to find a set of spray settings which can be used to achieve one particular set of desired final (and measurable) properties of the coating. At present, these desired outcomes are based on specific industrial requirements based on total porosity demands and most frequent porosity aspect ratio. The FABERCOAT system includes a model for the plasma spray manufacturing process developed and validated within the CEC project. The model has been used to “harvest” the information gained in the extensive production and characterisation programme of the CEC project and has provided an innovative way of feeding back this information to the end-users.

Cooperative working environments and their development are becoming increasingly important and ever more frequent in different industrial sectors and this book provides a scientific approach for managing Team Engineering. Meta-cognitive knowledge and networks are identified as the key resources enabling engineering teams to work effectively and to reduce engineering time and this book illustrates how computer support can aid cooperative work within the context of practical methodologies and examples. The fields covered in the book include: State-of-the-art research in cooperative learning tools; Practical examples and methodologies illustrating the implementation of cooperative networks; and An interdisciplinary approach to team engineering. This valuable new book is sponsored by the International Federation for Information Processing (IFIP) and will be essential reading for researchers, engineers, technical managers involved in the development of advanced applications for engineering and manufacturing, and software design and engineering.

Introducing software reuse at a corporate level represents one of the most promising means of addressing the rising costs that are plaguing the software industry. A series of mechanisms are needed for shortening development cycles and providing reliable software of high quality which will be more maintainable and flexible for future extensions. This paper describes the experiences of Sodalia S.p.A., a young Italian company, in implementing such reuse methodology, particularly centred around a reuse tool specifically developed.

An AI adaptation methodology designed to assist in transporting agricultural models between regions is presented. A methodology to perform model adaptation (viz. localization) is frequently necessary when models are transported because models developed in one region often do not produce valid results when used in a different region. In this methodology, a GA plays the role of the adaptation agent. By linking a GA to an agricultural model, the model become more robust because it is able to adapt to the region in which the model is being used. This methodology has been implemented within a decision support system (DSS) developed within an EC project called SYBIL. The DSS helps farmers predict when diseases and funguses will attack their plants, so they can make intelligent decisions on preventing these attacks. Preliminary testing within this environment indicates this adaptation methodology has the ability to allow agricultural models developed in one area to be effectively utilized in other regions.

In the present article some industrial applications of computer simulations will be described in details. The developed models provide an innovative and much needed design tool that overcome the limitations of traditional empirical optimization procedures, such as high costs and difficulty in investigating every combination of production route and service condition.

Computer simulation experiments on transport properties using perturbation of mechanical trajectories are critically discussed in the light of Van Kampen's “case against linear response theory” and of the numerical experiments in the nonlinear region of Visscher, and more recently of Evans.

Mise en evidence du role dominant de la diffusion coherente a partir des ions Ag + ; bon accord avec les resultats experimentaux disponibles. Description satisfaisante du deplacement par saut des ions Ag + au moyen du modele de Chudley-Elliot, lorsque les caracteristiques geometriques necessaires des sites tetraedriques sont prises en consideration. Prevision des modes de phonons dus aux mouvements des ions I − pour certains vecteurs d'onde

Explicit saddle surfaces and return jump rates are calculated for model crystals; the results establish the validity of rate calculations for atomic jumps in solids. A nonphysical effect, in which isotopic substitution causes a "return jump catastrophe," is resolved by use of an exact momentum-dependent criterion to distinguish successful jumps.

We report calculations of the dynamical structure factor S ( Q , ω) of Na at temperatures close to melting. Particular attention is given to the dependence of S ( Q , ω) on the momentum transfer Q. For phonons propagating in the [110] direction we trace the disappearance of the one phonon peak into the multiphonon background.

The free energy of formation of vacancies in rare gas crystals is evaluated directly from Monte Carlo simulation of a perfect crystal and a crystal containing a vacancy, without the help of intermediate systems. For solid argon at high temperature we find ΔG v = 1970 cal/mole - 3.1 k B T.

Path Integral Monte Carlo (PIMC) is one way of exploiting the connection between the diffusion equation and the Schrodinger equation for numerical computation based on sampling for quantum statistical mechanics. Starting from the introduction of the Wiener integral, that is the mathematical foundation supporting the numerical work, a number of methodological aspects of the implementation of PIMC are discussed, including suitable approximations to treat hard core particles, schemes for the calculation of free energy differences and of time dependent properties, and the problem of correlation and variance in the mean of estimators in Monte Carlo chains.

The recent observation of icosahedral atomic order in diffraction experiments from quasi-crystalline aluminium-manganese alloys had a precursor in the revelation by computer simulation of icosahedral bond orientational order in a supercooled monoatomic liquid.