Identification of IPMC nonlinear model via single and multi-objective optimization algorithms

Ionic Polymer–Metal Composites (IPMCs) are electro-active polymers transforming mechanical forces into electric signals and vice versa. This paper proposes an improved electro-mechanical grey-box model for IPMC membrane working as actuator. In particular the IPMC nonlinearity has been characterized through experimentation and included within the electric model. Moreover identification of the model parameters has been performed via optimization algorithms using both single- and multi-objective formulation. Minimization was attained via the Nelder–Mead simplex and the Genetic Algorithms considering as cost functions the error between the experimental and modeled absorbed current and the error between experimental and modeled displacement. The obtained results for the different formulations have been then compared.     

SCIDDICA-SS3: a new version of cellular automata model for simulating fast moving landslides

Cellular Automata (CA) are discrete and parallel computational models useful for simulating dynamic systems that evolve on the basis on local interactions. Some natural events, such as some types of landslides, fall into this type of phenomena and lend themselves well to be simulated with this approach. This paper describes the latest version of the SCIDDICA CA family models, specifically developed to simulate debris-flows type landslides. The latest model of the family, named SCIDDICA-SS₃, inherits all the features of its predecessor, SCIDDICA-SS₂, with the addition of a particular strategy to manage momentum. The introduction of the latter permits a better approximation of inertial effects that characterize some rapid debris flows. First simulations attempts of real landslides with SCIDDICA-SS₃ have produced quite satisfactory results, comparable with the previous model.     

Selection of a representative value function in robust multiple criteria sorting

We introduce the concept of a representative value function in robust ordinal regression applied to multiple criteria sorting problems. The proposed approach can be seen as an extension of UTADIS^GMS, a new multiple criteria sorting method that aims at assigning actions to p pre-defined and ordered classes. The preference information supplied by the decision maker (DM) is composed of desired assignments of some reference actions to one or several contiguous classes—they are called assignment examples. The robust ordinal regression builds a set of general additive value functions compatible with the assignment examples and results in two assignments: necessary and possible. The necessary assignment specifies the range of classes to which the action can be assigned considering all compatible value functions simultaneously. The possible assignment specifies, in turn, the range of classes to which the action can be assigned considering any compatible value function individually. In this paper, we propose a way of selecting a representative value function among the set of compatible ones. We identify a few targets which build on results of the robust ordinal regression and could be attained by a representative value function. They concern enhancement of differences between possible assignments of two actions. In this way, the selected function highlights the most stable part of the robust sorting, and can be perceived as representative in the sense of robustness preoccupation. We envisage two possible uses of the representative value function in decision support systems. The first one is an explicit exhibition of the function along with the results of the UTADIS^GMS method, in order to help the DM to understand the robust sorting. The other is an autonomous use, in order to supply the DM with sorting obtained by an example-based procedure driven by the chosen function. Three case studies illustrating the use of a representative value function in real-world decision problems are presented. One of those studies is devoted to the comparison of the introduced concept of representativeness with alternative procedures for determining a single value function, which we adapted to sorting problems, because they were originally proposed for ranking problems.     

IgA antibodies to tissue transglutaminase: An effective diagnostic test for celiac disease

OBJECTIVE: Tissue transglutaminase (tTG) is the main autoantigen recognized by endomysial antibodies. The aim of this study was to assess sensitivity, specificity, and predictive value of IgA and IgG antibodies to tTG in the diagnosis of celiac disease compared with endomysial antibodies. STUDY DESIGN: We established enzyme-linked immunosorbent assay procedures to measure IgA and IgG antibodies to tTG in sera from 48 untreated and 33 treated patients with celiac disease and from 63 patients with gastrointestinal disease who were in a control group. Sera from 10 patients with celiac disease were examined at various times after gluten was reintroduced into the patients' diet. RESULTS: Both IgA and IgG to tTG were significantly (P <.001) higher in serum of untreated patients with celiac disease versus those in the control group; IgA but not IgG was significantly (P <.001) higher in untreated versus treated patients with celiac disease. IgA and IgG antitissue tTG had a diagnostic sensitivity, specificity, and positive predictive value of 92% and 21%, 98% and 97%, and 98% and 83%, respectively. The concordance rate of IgA anti-tTG with IgA antiendomysial antibodies was 95%. In 5 of the 10 patients undergoing gluten challenge, IgA antiendomysium antibodies were detected earlier than IgA anti-tTG antibodies. CONCLUSIONS: tTG-based enzyme-linked immunosorbent assay is an effective diagnostic test, although immunofluorescent-based assays are more sensitive, particularly during gluten challenge.     

The hardy organization: Success by turning change to advantage.

Our turbulent times require organizations that are hardy in the sense of having cultures, climates, structures, and workforces capable of turning potentially disruptive changes into opportunities. At the individual, or workforce, level, hardiness involves the attitudes of commitment, control, and challenge and the complementary skills of coping and social support. At the organizational level, the isomorphic counterparts of hardy attitudes are the cultural values of cooperation, credibility, and creativity. Furthermore, an organization is hardy if these cultural values are indeed expressed on an everyday basis through its climate and if its structure involves the matrix management scheme of semi-autonomous work teams rather than the more traditional hierarchical arrangement. This article also considers the assessment and consulting functions that can increase the hardiness of organizations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Further insights into the mechanism of migration from the PVC gaskets of metal closures into oily foods in glass jars

Factors influencing migration from the gaskets of metal closures into oily foods were investigated. Tightening of the lid has an effect presumably through the deformation of the gasket, the amount of oil adhering to the latter, and the proportion of its surface being covered by oil. The substantial difference observed in the migration determined with the jar in an upright or a reversed position is partly related to this. The nature of the plasticizer determines the saturation in the partitioning process between the gasket and the small amount of oil in contact with the gasket as well as the adherence of oil (wettability). If saturation is rapidly reached, the frequency of exchanging the oil by shaking of the jar is an important factor. A complete exchange of the oil in contact with the gasket requires vigorous and persisting shaking, presumably because of the high viscosity and the hindered access to the angle between the gasket and the jar rim. The limited data available on long-term performance suggest that migration accelerates after roughly one year of storage. It is concluded that the extrapolation of long-term migration from short-term data presupposes a deeper investigation of the course of migration over years.     

DAQs-based wattmeters for high accuracy measurements. Comparison with the Italian power primary standard

This paper is focused on the use of data acquisition boards (DAQs) for the development of high accuracy PC-based instruments for the measurements of electrical power. The proposed systems are simple, portable and low cost because they are based on commercial data acquisition boards (DAQs) connected to a common personal computer. Data processing is carried out by a commercial software based on an interpolating windowed FFT. In the paper it is shown how the voltage can be sensed directly, thanks to the DAQ input range, thus avoiding expensive voltage dividers. The set up of the DAQs-based solutions is described and the evaluation of their metrological features is made by means of a comparison with the Italian power primary standard, which was built at INRIM with a complex solution and expensive with two high precision digital voltmeters.     

Enhanced Photostability of Fluoroquinolone Antibacterials Capped on Silver Nanoparticles

The photolabile and phototoxic fluoroquinolone (FQ) antibacterial drugs norfloxacin and rufloxacin have been used as capping agents for 25 nm Ag nanoparticles, exploiting the noncovalent interaction between the cationic piperazinyl ring of both FQs and the negatively charged metal surface. The resulting FQ‐protected silver nanoclusters (Ag@FQs), ca. 80 nm in diameter, are dispersible in phosphate buffer at physiological pH and their response to light excitation has been studied by steady‐state and time‐resolved spectroscopic and photochemical techniques. The fluorescence emission of the FQs chromophores is not extensively quenched in the Ag@FQs. In contrast, both Ag@FQs exhibit a photochemical stability more than one order of magnitude larger than that of the free drugs. This is the result of significant and differentiated quenching effects by the Ag surface on the kinetic and population of the excited triplet states of FQs, which are the key intermediate in the drugs photodecomposition. In view of the well‐known antimicrobial properties of the Ag nanoparticles, the Ag@FQs could represent intriguing nanohybrids in the perspective multifunctional nanodrugs.     

Laser irradiation of ZnO:Al/Ag/ZnO:Al multilayers for electrical isolation in thin film photovoltaics

Laser irradiation of ZnO:Al/Ag/ZnO:Al transparent contacts is investigated for segmentation purposes. The quality of the irradiated areas has been experimentally evaluated by separation resistance measurements, and the results are complemented with a thermal model used for numerical simulations of the laser process. The presence of the Ag interlayer plays two key effects on the laser scribing process by increasing the maximum temperature reached in the structure and accelerating the cool down process. These evidences can promote the use of ultra-thin ZnO:Al/Ag/ZnO:Al electrode in large-area products, such as for solar modules.