Behaviour of compacted silt used to construct flood embankment

This paper investigates the unsaturated mechanical behaviour of a fill material sampled from flood embankments located along the Bengawan Solo River in Indonesia. In order to gain a better understanding of this fill material, in situ tests were carried out alongside an extensive laboratory programme. Two different phenomena related to changes in moisture content of the embankment fill material are experimentally studied herein: (a) volumetric collapse and (b) variation in shear strength with suction. At low densities, similar to those found in situ, the material exhibited significant volumetric collapse behaviour. Triaxial tests carried out under saturated, suction-controlled and constant water content conditions indicate that the shear strength of the material increased with suction; in particular the effective angle of friction increased from 24.9 degrees under saturated conditions to 35.8 degrees under air-dried conditions

Fracture Criterion for Surface Cracks in Plates under Remote Tension Loading

Surface-crack configurations are among the most important crack problems in the aerospace industry. The residual strength of a surface-cracked component is complicated by three-dimensional variation of the stress-intensity factor around the crack front and plastic deformations, which vary from plane stress at the free boundary, to nearly plane-strain behavior in the interior. In 1973, a two-parameter fracture criterion (TPFC) was developed to analyze fracture behavior of surface-crack configurations. Estimates were made around the crack front for fracture initiation—the critical parametric angle. Recently, NASA developed the Tool for Analysis of Surface Cracks (TASC) software that predicts critical location. This thesis is the application of the TPFC with the TASC critical angles using an equation developed from the TASC software. The TPFC was applied to three materials: a brittle titanium alloy, a ductile titanium alloy, and a ductile 301 stainless steel. The TPFC with the TASC critical angles correlated fracture behaviors well

Quantification of the performance of iterative and non-iterative computational methods of locating partial discharges using RF measurement techniques

Partial discharge (PD) is an electrical discharge phenomenon that occurs when the insulation materialof high voltage equipment is subjected to high electric field stress. Its occurrence can be an indication ofincipient failure within power equipment such as power transformers, underground transmission cableor switchgear. Radio frequency measurement methods can be used to detect and locate discharge sourcesby measuring the propagated electromagnetic wave arising as a result of ionic charge acceleration. Anarray of at least four receiving antennas may be employed to detect any radiated discharge signals, thenthe three dimensional position of the discharge source can be calculated using different algorithms. These algorithms fall into two categories; iterative or non-iterative. This paper evaluates, through simulation, the location performance of an iterative method (the standardleast squares method) and a non-iterative method (the Bancroft algorithm). Simulations were carried outusing (i) a "Y" shaped antenna array and (ii) a square shaped antenna array, each consisting of a four-antennas. The results show that PD location accuracy is influenced by the algorithm's error bound, thenumber of iterations and the initial values for the iterative algorithms, as well as the antenna arrangement for both the non-iterative and iterative algorithms. Furthermore, this research proposes a novel approachfor selecting adequate error bounds and number of iterations using results of the non-iterative method, thus solving some of the iterative method dependencies

Detoxification and decolorization of Moroccan textile wastewater by electrocoagulation: energetic and toxicological evaluation

In Morocco the textile industry, representing 31% of all Moroccan industries, is accompanied by high water consumption and important wastewater discharges rejected without any treatment. The focus of this study was to characterize the effluent from the local textile industry and to carry out the treatment by electrocoagulation (EC).The effect of electrode materials, pH, applied current density and treatment time on decolorization, COD removal and toxicity aspect of the effluent. Results have indicated that the treatment efficiency was significantly improved by varying the current density, pH and operating time when Al and Fe electrodes were used for EC. The appropriate electrode type search for EC provided that aluminium supplies more COD removal (78%) than iron electrode (56%) at the end of the 25 min operating time and increased BOD5/COD index from 0.29 to 0.50.Whereas EC with iron electrodes was more beneficial for color removal 91% after 25 min of EC. The evaluation of toxicity by Daphnia magna test has shown that the effluent have a high toxicity. However electrocoagulation significantly reduced the toxicity of the effluent. Keywords: daphnia test; toxicity; operating cost; decolorization.

Spécification et Validation d'un Contrôleur de Performances Sportives

International audienceCe papier a pour objectif de montrer l'intérêt d'utiliser les méthodes formelles pour spécifier et valider un système médical, nous utilisons les automates hiérarchiques pour modéliser ces systèmes. La sémantique utilisée est celle d'une structure de Kripke où les états sont valués par des propositions atomiques. Cette structure peut être de grande taille en nombre d'états. Par nature, les systèmes hiérarchiques sont définis de manière hiérarchique par un ensemble de sous systèmes en éclatant à chaque fois un ou plusieurs états en un ensemble d'automates. Dans cet article, nous proposons de vérifier des proporiétés, seulement sur ces sous-systèmes. Pour pallier au problème de l'explosion combinatoire et la vérification de propriétés, nous considérons que les sous systèmes concernés par la propriété à vérifier et en déduire sa vérification sur le système global. Les résultats sont illustrés sur l'exemple d'un contrôleur de performances sportives

Politiques d'adaptation pour la reconfiguration du composant de localisation

International audienceLes approches à base de composants sont intensivement étudiées dans le cadre des systèmes complexes. Ces approches visent à concevoir des systèmes et des applications par assemblage de composants préfabriqués, réutilisables et faciles à maintenir. Afin de répondre à des besoins spécifiques, une des approches est l'utilisation de politiques d'adaptation permettant de reconfigurer dynamiquement le modèle à composants par rapport au contexte de son environnement. Le travail présenté dans cet article repose sur un cadre formel permettant de décrire des politiques d'adaptation appliquées à un composant de localisation. Ce composant, que nous spécifions en Fractal, permet de fournir une position optimale, obtenue à partir de plusieurs positions fournies par plusieurs systèmes de localisation (GPS, Wifi). Nous définissons deux politiques d'adaptation pour ce composant et simulons son fonctionnement sur une extension de Fractal. Suite aux expérimentations, nous proposons une extension des politiques d'adaptation pour prendre en compte de nouveaux aspects non fonctionnels

Assembly of components based on interface automata and {UML} component model

International audienceWe propose an approach which combines component UML model and interface automata in order to assemble components and to verify their interoperability. We specify component based system architecture with component UML model, and component interfaces with interface automata. Interface automata is a common Input Output (I/O) automata-based formalism intended to specify the signature and the protocol level of component interfaces. We improve interface automata approach by component UML model, in order to consider system architecture, in component composition and interoperability verification methods. Therefore, we handle in interface automata, the connection between components, and the hierarchical connections between composite components and their subcomponents

Refinement of Interface Automata Strengthened by Action Semantics

International audienceInterface automata are light-weight models that capture the temporal interface behavior of software components. They have the ability to model both the input requirements and the output behavior of a component. They support the compatibility check between interface models to ensure a correct interaction between components and they adopt an alternating simulation approach to design refinement. In this paper, we extend our previous works on checking interface automata interoperability by adapting their alternating refinement relation to the action semantics. We show the relation between pre and post-conditions of transitions in the abstract version of an interface and their corresponding ones in its concrete version. We illustrate our extensions by a case study of the CyCab car component-based system

Adapting Components Behaviours using Interface Automata

International audienceOne of the principal goal of Component-Based Software Engineering (CBSE) is to allow the reuse of components in diverse situations without affecting their codes. To reach this goal, it is necessary to propose approaches to adapt a component with its environment when behavioural mismatches occur during their interactions. In this paper, we present a formal approach based on interface automata to adapt components in order to eliminate possible behavioural mismatches, and then insure more flexible interoperability between component