Performance of a demand controlled mechanical extract ventilation system for dwellings

The main aim of ventilation is to guarantee a goodindoor air quality, related to the energy consumed forheating and fan(s). Active or passive heat recoverysystems seem to focus on the reduction of heatingconsumption at the expense of fan electricityconsumption and maintenance. In this study, demandcontrolledmechanical extract ventilation systems ofRenson (DCV1 and DCV2), based on natural supply inthe habitable rooms and mechanical extraction in thewet rooms (or even the bedrooms), was analysed forone year by means of multi-zone Contam simulationson a reference detached house and compared withstandard MEV and mechanical extract ventilationsystems with heat recovery (MVHR). To this end, IAQ, total energy consumption,CO2 emissions and total cost of the systems aredetermined. The results show that DCV systems withincreased supply air flow rates or direct mechanicalextract from bedrooms can significantly improve IAQ,while reducing total energy consumption comparedto MEV. Applying DCV reduces primary heatingenergy consumption and yearly fan electricityconsumption at most by 65% to 50% compared toMEV. Total operational energy costs and CO2emissions of DCV are similar when compared toMVHR. Total costs of DCV systems over 15 years aresmaller when compared to MVHR due to lowerinvestment and maintenance costs

Targeting surface nucleolin with a multivalent pseudopeptide delays development of spontaneous melanoma in RET transgenic mice

<p>Abstract</p> <p>Background</p> <p>The importance of cell-surface nucleolin in cancer biology was recently highlighted by studies showing that ligands of nucleolin play critical role in tumorigenesis and angiogenesis. By using a specific antagonist that binds the C-terminal tail of nucleolin, the HB-19 pseudopeptide, we recently reported that HB-19 treatment markedly suppressed the progression of established human breast tumor cell xenografts in the athymic nude mice without apparent toxicity.</p> <p>Methods</p> <p>The <it>in vivo </it>antitumoral action of HB-19 treatment was assessed on the spontaneous development of melanoma in the RET transgenic mouse model. Ten days old RET mice were treated with HB-19 in a prophylactic setting that extended 300 days. In parallel, the molecular basis for the action of HB-19 was investigated on a melanoma cell line (called TIII) derived from a cutaneous nodule of a RET mouse.</p> <p>Results</p> <p>HB-19 treatment of RET mice caused a significant delay in the onset of cutaneous tumors, several-months delay in the incidence of large tumors, a lower frequency of cutaneous nodules, and a reduction of visceral metastatic nodules while displaying no toxicity to normal tissue. Moreover, microvessel density was significantly reduced in tumors recovered from HB-19 treated mice compared to corresponding controls. Studies on the melanoma-derived tumor cells demonstrated that HB-19 treatment of TIII cells could restore contact inhibition, impair anchorage-independent growth, and reduce their tumorigenic potential in mice. Moreover, HB-19 treatment caused selective down regulation of transcripts coding matrix metalloproteinase 2 and 9, and tumor necrosis factor-α in the TIII cells and in melanoma tumors of RET mice.</p> <p>Conclusions</p> <p>Although HB-19 treatment failed to prevent the development of spontaneous melanoma in the RET mice, it delayed for several months the onset and frequency of cutaneous tumors, and exerted a significant inhibitory effect on visceral metastasis. Consequently, HB-19 could provide a novel therapeutic agent by itself or as an adjuvant therapy in association with current therapeutic interventions on a virulent cancer like melanoma.</p

Salmonellosis with Salmonella typhi murium in the foal

Les auteurs décrivent l’apparition de foyers importants de Salmonel lose équine en France en 1981, provoquant la mort de jeunes poulains de 1 à 3 mois et quelques avortements sur les juments. Le portage par les animaux adultes apparemment sains est important. Cette épidémie de Salmonelloses est due à Salmonella typhimurium V. Copenhague, si cette salmonelle appartient à un biotype particulier (biotype b) connu, elle appartient par contre à un lyzotype encore inconnu en France. Cette salmonelle a d’autre part la particularité d’être multirésistante aux antibiotiques et, de ce fait, les auteurs attirent l’attention des vété rinaires, éleveurs et médecins en leur demandant une grande vigilance et une certaine prudence concernant des traitements intempestifs et « aveu gles » avec des antibiotiques.The authors describe some outbreaks of equine salmonellosis which occured in France during 1981, inducing the death of 1 to 3 months old foals and some abortions on the mares. This epizooty was due to Salmonella typhimurium v. Copenhagen, this salmonella belongs to a special biotype (biotype b) already known but to a lysotype still un know in France. This salmonella has also the characteristic of being multiresistant to antibiotics and the authors draw the attention of the veterinarians, breeders, and physicians on this fact and ask hem to be vigilant and cautions toward the use of «blind» treatements with antibiotics

Characterization by PIV of the Effect of Vortex Generators in a Transonic Separated Flow

The present study is aimed to analyse the effect of passive vortex generators in a transonic interaction between a shock-wave and a turbulent boundary layer in a channel flow at Mach number M = 1.45. Control of the boundary layer detachment downstream of the shock is obtained thanks to momentum transfer given by passive control devices, mechanical vortex generators (VG), located upstream of the shock and distributed in the spanwise direction. The channel\u92s lower wall is equipped with a contour profile - a bump - allowing flow separation. Two-component PIV velocity measurements are performed using the iterative gradient-based cross-correlation algorithm FOLKI-SPIV developed at ONERA. The evolution of the bulk flow and of the separated bubble due to the shock-wave boundary layer interaction is accurately quantified. Changes in the turbulent behaviour are also analysed thanks to the fluctuating fields. Comparisons with the already known flow without control give an appraisal of the effectiveness of such devices

Mesure par velocimetrie laser a franges classique a 50 #mu#m d'une paroi

Communication to : 9eme congres francophone de velocimetrie laser, Bruxelles (Belgique), 14-17 septembre 2004Available from INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.2004 n.209 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Simulation experimentale et numerique du comportement d'un ventilateur de climatisation automobile

Communication to : 5e congres francophone de velocimetrie laser, Rouen (France), 24-27 septembre 1996Available from INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.1997 n.210 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Les expériences en mécanique des fluides s'orientent vers le 3D : Nouveaux traitements numériques pour l'imagerie 3D instantanée quantitative de fluides

International audienceWe review recent developments made between three departments at ONERA (DTIM, DAFE, DMAE) with regard to 3D imagery used in fluid mechanics experiments. We first discuss 3D PIV (Particle Image Velocimetry) and present original contributions on the modeling of the imaging process, the reconstruction of the 3D volume of particles and the estimation of the 3D motion field between two time instants. These three contributions emphasize the pointwise character of particles in PIV, in contrast with classical Tomo-PIV approaches, and have been shown to outperform state-of-the-art methods, yielding more accurate 3D velocity estimations. Then, we consider 3DBOS (Background Oriented Schlieren), which is aimed at estimating the instantaneous 3D density field of a moving fluid. We have recently proposed an original one-step numerical approach for 3DBOS. This method has been successfully used in several experiments conducted in various ONERA facilities, in particular in the F2 and S1MA wind tunnels. Finally, we draw some important perspectives, especially for the study of compressible flows by combining both techniques.Nous présentons les résultats récents concernant la mesure volumique 3D par imagerie en mécanique des fluides expérimentale, issus de développements menés entre les trois départements DTIM, DAFE et DMAE de l’ONERA. Nous discutons d’abord de la mesure 3D de vitesse par imagerie de particules (3D PIV). Nos contributions originales concernent le modèle d’imagerie lui-même, la méthode de reconstruction 3D du volume de particules et l’estimation du champ de déplacements 3D. Leur principe est globalement d’exploiter le caractère ponctuel des particules et de chercher à recourir à des méthodes parcimonieuses (sparse). Ces approches nous ont permis d’atteindre ou même de dépasser l’état de l’art en termes de qualité d’estimation et d’efficacité algorithmique. Nous abordons ensuite la mesure 3D instantanée de la masse volumique par des méthodes de strioscopie BOS (Background Oriented Schlieren). Nous avons proposé récemment une structure originale d’estimation en une étape de la masse volumique à partir des mesures de déviation de la lumière traversant un fluide inhomogène. Cette méthode a été utilisée avec succès dans plusieurs installations expérimentales de l’ONERA, notamment dans les souffleries F2 et S1MA. Enfin, nous traçons quelques perspectives de ces développements en particulier pour la caractérisation expérimentale des fluides compressibles

Lucas–Kanade fluid trajectories for time-resolved PIV

International audienceWe introduce a new method for estimating fluid trajectories in time-resolved PIV. It relies on a Lucas-Kanade paradigm and consists in a simple and direct extension of a two-frame estimation proposed in that context. The so-called Lucas-Kanade Fluid Trajectories (LKFT) are assumed to be polynomial in time, and are found as the minimizer of a global functional, in which displacements are sought so as to match the intensities of a series of image pairs in the sequence, in the least-squares sense. All pairs involve the central image, similar to other recent time-resolved approaches (FTC and FTEE). As switching from a two-frame to a time-resolved objective simply amounts to adding terms in a functional, no significant additional algorithmic element is required, and similar to FOLKI-SPIV, the method has an important potential for GPU acceleration. Tests on synthetic data with translating and rotating motions show that in the current implementation, and using a cubic B-Spline interpolator for image deformation, LKFT has a total error comparable to that of FTEE, while improvements can still be brought to the algorithm. Besides, results on case B of the third PIV challenge confirm its ability to drastically reduce the random error in situations with low signal-to- noise ratio