Metallic content of wines from the Canary Islands (Spain). Application of artificial neural networks to the data analysis

Eleven elements, K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb, were determined in dry and sweet wines bearing the denominations of origin of El Hierro, La Palma and Lanzarote islands (Canary Islands, Spain). Analyses were performed by flame atomic absorption spectrophotometry, with the exceptions of Li and Rb for which flame atomic emission spectrophotometry was used. The content in copper and iron did not present risks of cases. All samples presented a copper and zinc content below the maximum amount recommended by the Office International de la Vigne et du Vin (OIV) for these elements. Significant differences in the metallic content were found among the different islands. Thus, Lanzarote presented the highest mean content in sodium and lithium and the lowest mean content in rubidium, and La Palma presented the highest mean content in strontium and rubidium. Sweet wines from La Palma, elaborated as naturally sweet with over-ripe grapes, presented mean contents significantly higher with regard to dry wines from the same island in the majority of the analysed elements. Cluster analysis and Kohonen self-organising maps showed differences in wines according to the island of origin and the ripening state of the grapes. Back-propagation artificial neural networks showed better prediction ability than stepwise linear discriminant analysis.     

Delay in Statistical Control of Systems with Wear

The target of statistical process control is to identify changes in the behavior of controlled process as quickly as possible. Therefore, as a quality measure of control charts, we use characteristics which quantify the delay between the occurrence of change and its identification by the control chart. The average run length is a commonly used characteristic which does not reflect a real situation. A new characteristic is suggested which is computed in the case of progressive wearing out of the system. We assume several types of progression. The Markov chain approach is used for computation of average delay. Copyright © 2011 John Wiley & Sons, Ltd.     

Fabrication of composite microcapsules by drop-on-demand inkjet: Effect of precursor composition on the process limits

The feasibility of using drop-on-demand inkjet technology for the fabrication of calcium alginate hydrogel microcapsules containing dispersed sub-micron solid particles (TiO₂ photocatalyst) was demonstrated. The influence of the printed solution viscosity on the micro-droplet size has been investigated and a study of the effect of solids fraction in the suspension on its printability was carried out. It was found that solutions with viscosities of up to 28 mPa s and solids content of up to 7.8 vol% can be reproducibly printed, resulting in droplets ranging from 45 to 105 μm depending on the inkjet operating conditions. In order to ensure stable and reproducible droplet formation, a pressure difference ranging from −200 to −1800 Pa had to be maintained in the nozzle. A uniform distribution of dispersed solids in the resulting microcapsules was achieved by adjusting pH and viscosity. The relationship between the printhead operating pressure, the fluid viscosity, the solids loading and the final size of the obtained microcapsules was established, allowing rapid prototyping of artificial cell-like structures with internal solid inclusions by the inkjet method.     

Qualitative, semiqualitative and interval algebras, and their application to engineering problems

This paper proposes the use of semiqualitative modelling for reasoning about the behaviour of complex physical systems. Semiqualitative modelling is a generalization of qualitative modelling which refines the set of intervals that values may be expressed in. Semiqualitative algebras are introduced, their most important features discussed, and related to qualitative algebras. The advantages that semiqualitative modelling offers over qualitative modelling are demonstrated by the solution of an example from the field of biotechnology. Finally, interval algebras are introduced as a generalization of semiqualitative algebras, and it is proved that it is possible to switch between different interval algebras in the course of computation in order to preserve the greatest possible degree of precision.     

Reliability knowledge and fractal evaluation of chaos

Fractal analysis has been used for the study of chaos in a number of two or three dimensional-physical systems. Iits possible role in the evaluation of reliability knowledge bases is studied in this paper. The difficulty in applying fractal analysis to knowledge bases is in finding a generic notion of scale which may be applicable to both numberical and symbolic data. We present here some notions of scale and of detail in relation to a set of fuzzy conditional statements. The only precondition for the application of fractal analysis is an ability to distinguish between specific and general knowledge items. A realistic case study (control valves) is presented in details.     

A SEMIQUALITATIVE REASONING AND ITS REALISTIC APPLICATIONS

The goal of this paper is to develop an algorithm for dealing with semiqualitative knowledge that keeps advantages of both qualitative quantification (positive, zero, negative) and order of magnitude (... 0,10, 100,...)knowledge systems and eliminates their disadvantages. A set of numerical intervals I_j =(positive values) can be used to quantify e.g. constants of a mathematical model. A dynamic behaviour is described as an oriented graph, where nodes are defined by sets of intervals and a set of arcs specifies all possible transitions. A case study (5 differential equations/chemical reactor) is given in full detail.     

Fuzzy simulation of industrial problems

Fuzzy analysis of engineering problems is less than a decade old. In spite of this, fuzzy mathematics offers a useful tool to deal with practical engineering tasks. A simple and efficient algorithm is described which can be used to model even such processes as those where more than 20 independent variables have to be considered. It is fairly easy to develop a simple program based on the algorithm presented here; and; it can be run using a relatively small computer.A result of fuzzy simulation is fuzzy. The article analyses all basic features of the resulting fuzzy set. Some practical recommendations are given on how to combine conventional numerical and fuzzy models to form mixed models.     

DIS — Design integrated system

Analysis of the work of the chemical process designer has revealed that his activity - in essence, repeated synthesis such as analysis problem-solving - has its own structure so it may be regarded as a system. An attempt has been made to construct a modular computer programming system to support the process designer's work. The programming system's modules reflect nodal designing activity such as balancing, simulation, economic evaluation and optimization, and the necessary transfer of information from one design step to another is secured by integral communication between the modules. Particular attention has been paid to the development of a designer-machine interface to enable an easy dialogue with the programming system. Features of the Design Integrated System are shown by applying DIS to a simple but typical chemical process.     

Inkjet fabrication and characterization of calcium alginate microcapsules

The present work describes a method for producing calcium alginate hydrogel microcapsules in the size range of 50-70 μm by means of a piezoelectric drop-on-demand inkjet device. Particles were prepared by emitting droplets of 0.5% and 1% (w/w) sodium alginate solutions into a magnetically stirred pool of CaCl₂ solution of variable viscosity ranging from 1 to 100 mPas. The effect of viscosity on the morphology of the resulting microcapsules was systematically investigated — lower viscosity of the receiving solution has lead to the formation of elongated particles, medium viscosities lead to spherical capsules, and for higher viscosities flattened particles were obtained. The applied voltage used for driving the piezoelectric inkjet print-head was found to be the most significant parameter for influencing the droplet size. The duration of the voltage pulse or the droplet viscosity had only minor effects. The release rates of two model substances (methylene blue dye and vitamin B12) from alginate beads were measured and their effective diffusion coefficients determined as function of alginate concentration.