Experimental and numerical investigation on single specimen methods of determination of J in rubber materials

In this paper, we have verified the validity of some formulations allowing the determination of the fracture surface energy in the case of rubber-like materials. The J-integral is chosen as a fracture characterizing parameter which is experimentally determined by considering a multiplying form that; numerically evaluated using a finite element method. The numerical results are compared to the experimental data and a good agreement has been pointed out for the deeply cracked specimen (a/w0.5). Below this limit, a significant divergence is observed which is attributed to a lack of accuracy of the experimental data processing.     

Canopy bidirectional reflectance calculation based on Adding method and SAIL formalism: AddingS/AddingSD

The SAIL model (proposed by Verhoef) is largely used in the remote sensing community to calculate the canopy Bidirectional Reflectance Distribution Function. The simulation results appear acceptable compared to observations especially for not very dense planophile vegetation. However, for erectophile dense crops (e.g. corn) the simulations appear less accurate. This inadequacy is due to the assumption that the multiple scattered fluxes are isotropically distributed. The SAIL parameters are interpretable at the level of elementary layer components. Now, the Adding method (initially proposed by Van de Hulst) provides a good framework to model the radiative transfer inside a vegetation layer, but its parameter estimation lies on very simple geometric modeling of the canopy. In this paper, we first propose an adaptation of the Adding method using the SAIL model canopy representation in the turbid case: it is called AddingS model. Such an approach allows to overcome the isotropy assumption. Second, AddingS is extended to the Discrete case: defining the AddingSDmodel. It allows to take into account the multi hot spot effect. Moreover, the AddingS and AddingSD models allow to check the energy conservation in respectively turbid and discrete cases. Finally, in order to keep reasonable time performance, a fast computation method was developed.     

Detection and resolution of semantic inconsistency and redundancy in an automatic ontology merging system

In recent years, researchers have been developing algorithms for the automatic mapping and merging of ontologies to meet the demands of interoperability between heterogeneous and distributed information systems. But, still state-of-the-art ontology mapping and merging systems is semi-automatic that reduces the burden of manual creation and maintenance of mappings, and need human intervention for their validation. The contribution presented in this paper makes human intervention one step more down by automatically identifying semantic inconsistencies in the early stages of ontology merging. We are detecting semantic heterogeneities that occur due to conflicts among the set of Generalized Concept Inclusions, Property Subsumption Criteria, and Constraint Satisfaction Mechanism in local heterogeneous ontologies, which become obstacles for the generation of semantically consistent global merged ontology. We present several algorithms to detect such semantic inconsistencies based on subsumption analysis of concepts and properties in local ontologies from the list of initial mappings. We provide ontological patterns for resolving these inconsistencies automatically. This results global merged ontology free from ??circulatory error in class/property hierarchy??, ??common class between disjoint classes/properties??, ??redundancy of subclass/subproperty of relations?? and other types of ??semantic inconsistency?? errors. Experiments on the real ontologies show that our algorithms save time and cost of traversing local ontologies, improve system??s performance by producing only consistent accurate mappings, and reduce the users?? dependability for ensuring the satisfiability of merged ontology.     

Effect of NA-light radiation on the optical gap and crystal structure of AgNO3-diffused PVDF sensor

A casting method was used to prepare polyvinylidene fluoride (PVDF) and 1 wt % MnCl₂-filled PVDF films. AgNO₃ was allowed to diffuse through the filled films. The 3 types of the prepared films were irradiated by Na light with various doses. The post-irradiation and relaxation effects were investigated using ultraviolet–visible spectroscopy, X-ray analysis, and optical microscopy. The results were interpreted on the bases of a theoretical model previously suggested for a build-up and decay of radiation-induced conductivity associated with the transition of charge carriers in the presence of a uniform trap distribution. Various structures were proposed for the diffused AgNO₃ before and after irradiation. It was found that the induced change in optical gap, due to 5-min irradiation time for the AgNO₃ diffused films, exhibits no relaxation phenomenon. Accordingly, this film can be used in photorecording applications. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1759–1767, 1998     

Kapillarrheometrie von Aluminiumoxid-Silikonöl-Suspensionen

The capillary rheometry measurements of concentrated suspensions of aluminum oxide hydroxide in silicon oil are described. The dimension of the extrusion dies was varied. The shear-stress curves and the pressure drop at sudden reduction of the cross section were ascertained. The influence of the properties of the solid phase (particle size, particle size distribution, particle geometry) and the concentration of the solid phase (40–65 wt.-%) on the flow behavior of the suspension were also investigated.     

Experimental design to optimize preparation of activated carbons for use in water treatment

A series of seven activated carbons was obtained for use in drinking water treatments by steam-activation of olive-waste cakes. This raw material is an abundant and cheap waste byproduct of oil production, making these activated carbons economically feasible. The activated carbons, prepared by the one step method, were characterized, and the evolution of their characteristics (yield, adsorption capacities, and porosity) was analyzed as a function of the experimental parameters (activation temperature and activation time), using the Doehlert matrix. The Doehlert matrix allows the response surface to be studied with a good quality parameter estimation of the quadratic model. Each response has been described by a second order model that was adequate to predict responses in all experimental regions. The coefficients of the postulated model were calculated from the experimental responses by means of least squares regression, using the NEMROD software. We determined the region in which the optimum values of both activation temperature and activation time were achieved for the preparation of activated carbons suitable for use in water treatments. The "optimal activated carbon" was experimentally obtained, and its characteristic parameters showed a good agreement with those calculated from the model. The results obtained for activated carbons prepared by the one-step method were compared with those for activated carbons prepared by the two-step method. The characteristics of activated carbons obtained by the one-step and two-step methods showed that "one-step" activated carbons have a highly developed porous texture formed mainly of large macropores and micropores, whereas "two-step" activated carbons have a predominance of mesopores and narrow micropores. These activated carbons from olive-waste cakes showed a high capacity to adsorb herbicides (2,4-dichlorophenoxyacetic acid, 2,4-D; and 2-methyl, 4-chlorophenoxyacetic acid, MCPA) from water, with adsorption capacity values higher than those corresponding to a commercial activated carbon used from drinking water treatments.     

Design of a perfect black absorber at visible frequencies using plasmonic metamaterials

The design and fabrication of a plasmonic black absorber with almost 100% absorbance spanning a broad range of frequencies from ultraviolet (UV) to the near infrared (NIR) is demonstrated. The perfect plasmonic absorber is achieved by a combination of a metal film with suitable metal/dielectric nanocomposites. Our fabrication technique is simple, versatile, cost-effective, and compatible with current industrial methods for solar absorber production.     

A fuzzy expert system for loss reduction and voltage control in radial distribution systems

In this paper, two methods for improving voltage profile and minimizing total system losses in radial distribution feeders are presented. The first method concerns with the capacitor allocation problem. Fuzzy expert system (FES) is used to select the best candidate nodes for capacitors to be installed in order to maximize total loss reduction and total net savings. The second method illustrated the voltage regulator problem. In this method, the location and the tapping ratio of the voltage regulators are determined in order to minimize total system losses while keeping the voltage within specified limits. The two methods have been applied to two test feeders. Comparison with other techniques is included to ensure methods validity and superiority.