Towards a smarter directional data aggregation in VANETs

World Wide Web - In the last decade, Vehicular Ad hoc NETworks (VANETs) have attracted researchers, automotive companies and public governments, as a new communication technology to improve the...     

Fatty acid methyl esters (FAME) from oleaginous seeds grown in arid lands. Part II: Ibicella lutea,Onopordum nervosum,Peganum harmala,Smyrnium olusatrum and Solanum elaeagnifolium

The properties of fatty acid methyl esters (FAMEs) obtained from Tunisian oleaginous seeds, grown in arid places with no need of supplementary water, are studied to assess their potential use as biodiesel: devil horn Ibicella lutea, cotton thistle Onopordum nervosum arabicum, Sirian rue Peganum harmala, horse celery Smyrnium olusatrum and silverleaf nightshade Solanum elaeagnifolium. Some key properties such as cloud point, pour point, cold filter plugging point, oxidation stability, cetane number, density, kinematic viscosity, heating value and oxygen extended sooting index have been predicted using equations that correlate the above properties with their ester profiles.     

Use of limestone sands and fillers in concrete without superplasticizer

This paper deals with the effects of the amount of limestone fillers with respect to the rheological, mechanical, and dimensional properties of concretes without superplasticizer. These concretes were made with two limestone coarse aggregates and one limestone sand from the same quarry, in order to avoid any artifact. Five sand containing fillers rate between 1.8% and 24% – representative rates of the categories defined in the EN 12260 norm for aggregates for concretes – were produced by mixture of original sand with its fine fraction or its grained fraction extracted beforehand by washing. The concretes were mix designed with the BetonlabPro2 software, whose algorithms take into account the presence of the limestone fillers. The experimental results show that the concretes containing from 100 to 150 kg/m³ limestone fillers often present optimal properties, with equal consistency. But, higher quantities of fillers do not deteriorate significantly the properties of the concretes, even if their packing density decreases. This behavior is explained not only by the binding effect allotted to the limestone fillers, but also by an improvement of the paste-aggregates bond.     

Facial-expression recognition based on a low-dimensional temporal feature space

Multimedia Tools and Applications - This paper suggests a facial-expression recognition in accordance with face video sequences based on a newly low-dimensional feature space proposed. Indeed, we...     

Study of electromagnetic waves diffraction by bi-dimensional fractal structures using the renormalization method

The analysis of fractal structures by conventional methods gets harder and harder when the number of length scales rises. In this study, we try to combine the renormalization method and the surface impedance model to help rigorous studying of electromagnetic diffraction of fractal structures at their final (infinitum) iteration. As an application, we applied the method to a couple of fractal structures: Cantor Iris 1D and 2D.     

Contribution des fillers calcaires à l’adhérence pâte-granulat. Exemples tunisiens

This article presents compressive test results carried out on a series of hydraulic concrete mixes without admixtures based on Tunisian limestones aggregates. Their estimated strength was calculated with the French model of LCPC (Laboratoire Central des Ponts et Chaussées), which takes into account the effect of bond to the paste and the ceiling effect of the aggregates. To check the experimental values, the parameter of bond had to be associated the content of fillers aggregates, because the performances predicted by the model are lower than the measurements, at least beyond 10% of fillers. The assumption is that the presence of these fine elements, of comparable nature that the aggregates, improves adherence or linking between paste and aggregate, thanks to bringing together the properties of rigidity of the two materials and to a better homogeneity of the system. The relationship found between the calcareous filler ratio and the bond coefficient then makes it possible to extend the forecasts of the model to the hydraulic mixtures containing aggregates crushed limestones, naturally rich in fillers.      

Prediction of semi-elliptical defect form, case of a pipe subjected to internal pressure

The fatigue propagation of a semi-elliptical surface crack in a pipe subjected to internal pressure is always an open question in spite of a number of numerical works. The crack front development is generally predicted by empirical relationships or parameters c and m of the crack propagation law. This fatigue propagation in the case of a pipe subjected to internal pressure have been obtained using a special device allowed to produce an internal pressure up to 700 bars. The crack aspect ratio development is similar to that of a crack in a plate submitted to tension.