Methodology proposal for the life cycle sustainability assessment applied to retrofitting in a local context

In the European context of upgrading the housing stock energy performance, multiple barriers hinder the wide uptake of sustainable retrofitting practices. Moreover, some of these may imply negative effects often disregarded. Policy makers need to identify how to increase and improve retrofitting practices from the comprehensive point of view of sustainability. None of the existing assessment tools addresses all the issues relevant for sustainable development in a local situation from a life cycle perspective. Life cycle sustainability assessment methodology, or LCSA, analyzes environmental and socioeconomic impacts. The environmental part is quite developed, but the socioeconomic aspect is still challenging. This work proposes socioeconomic criteria to be included in a LCSA to assess retrofitting works in the specific context of Brussels-Capital Region. LCSA feasibility and challenging methodology aspects are discussed

Spectral analysis and experimental study of lateral capillary dynamics for flip-chip applications

This article presents a study on the dynamics of lateral motion of a liquid meniscus confined by a pad and a chip moving parallel to the pad. This problem is a typical flip-chip case study, whose use is widespread in industrial assembly. The proposed model describing this dynamics is built upon two coupled physics: the Navier-Stokes equation governing the liquid flow between the pad and the chip, and the Newton's law describing the motion of the chip. This coupled problem is solved with a spectral method based on Chebyshev polynomials, by assuming a linear analytical expression of the lateral stiffness of the meniscus in the cases of circular and square pads. The theoretical results are benchmarked with literature results and thoroughly experimentally validated. From these results, we propose a map giving the characteristic time of the chip dynamics according to only two non-dimensional parameters, constructed with the physical (density, surface tension, and viscosity), geometrical (pad area and gap), or dynamical (chip mass) parameters of the problem

Étude numérique comparative de l'écoulement de fluides compressibles non visqueux dans des tuyères bidimensionnelles et axisymétriques

info:eu-repo/semantics/publishe

Two-Fluid-Layer Flow Stability

The hydrodynamic stability of the flow of two superposed, immiscible, viscous fluids has attracted considerable theoretical and practical interest over many years. The practical applications for such a configuration are in coating and lubrication technologies, polymer processing and de-/anti-icing of aircraft wings in winter. Many aspects of this generic stability problem were explored intensively via perturbation and asymptotic methods (with their inherent limitations as to regions of validity) ever since late Professor C.-S. Yih tackled it in his JFM (Vol. 27, Part 2, pp. 337-352, 1997) paper and showed the destabilizing effect of viscosity stratification per se. He connected this work to an investigation (JFM, Vol. 212, pp. 41-53, 1990) on the interfacial wave formation on de-icing liquids sprayed on aircraft. In view of the ongoing certification studies on anti-/de-icing fluids being conducted over the years at the Von Karman Institute for Fluid Dynamics and the continuing development of such fluids by industry it was felt appropriate to look at the problem more comprehensively and generate a theoretical data base to complement the experimental data base being built up. In this process extensive parameter studies have been carried out on superposed fluid layers of finite and semi-infinite extent keeping newtonian and non- newtonian flows in view since many of the anti-icing fluids being designed by industry are in fact non-newtonian in character and quit often have been found to satisfy a power-law stress-rate-of-strain relationship. Since the parameters here are rather numerous: viscosity ratio (m), density ratio (r), thickness of the liqiud layer (l), surface tension (S), Froude number (F), and also the power-law index of the liquid (n), sweeping generalizations as to the dominance of the different instability mechanisms and their practical consequences do not seem advisable. However our studies taken together with those of Yih and his followers on 2D Couette, Poiseuille and boundary layer type of flows allow a reasonably well-rounded picture of the linear stability characteristics of this generic two-fluid layer configuration. An accurate and semi-automatic shooting search method for solving the associated eigenvalue problems has been developed and used for elaborate parameter studies. Results of these more comprehensive ongoing studies are presented and discussed against the backdrop of those available in the literature. New aspects treated here are the non-newtonian character of the fluids and effects of a turbulent profile (which is rather the rule in aeronautical practice) in the airflo

Impact carbonique et énergétique de capteurs solaires thermiques plans

Le bilan environnemental (carbone, énergie) de trois capteurs solaires thermiques produits en Belgique de 1979 à nos jours est proposé, en tenant compte des postes suivants : la production des matières premières, leur mise en forme. Les impacts respectifs de chaque fraction de matériau sont évalués. Le bilan est comparé avec les performances de ces capteurs, qui permettent de réduire la consommation en énergies fortement émettrices de CO2. Le temps de retour énergétique s’améliore sur le long terme, grâce à une meilleure sélection des matériaux. Le bénéfice de la réutilisation de certains composants est évalué, en tenant compte de la facilité de démontage