Dimensionnement optimal d'une pompe à chaleur thermoélectrique pour le chauffage de bâtiments à haute efficacité

International audienc

Investigation of the Nozzle Diameter as a Control Parameter of the Properties of Melt-Spun Sb2−x Bi x Te3.

International audienceThree kinds of Sb1.6Bi0.4Te3.1 samples were prepared by the melt-spinning technique using quartz tubes with different nozzle’s diameters (1.0, 0.7 and 0.5 mm) to study the sensitivity of the thermoelectric properties to the variations of this parameter. The melt-spun ribbons were densified by spark plasma sintering (SPS). The melt-spun samples were characterized by powder x-ray diffraction and scanning electron microscopy. The dimensionless figures of merit (ZT) were calculated from the data obtained by measuring the Seebeck coefficient, electrical resistivity and thermal conductivity in the direction perpendicular to the uniaxial pressing direction of SPS. All ZT values for this set of samples were close to 1.0 around 380 K. The highest ZT value was obtained for the sample prepared using the largest nozzle diameter of 1.0 mm. Despite some variations in the carrier concentrations of the samples being observed, these results indicate a weak sensitivity of the melt-spun Sb1.6Bi0.4Te3.1 samples to the nozzle’s diameter during the melt-spinning process

Influence of Preparation Processing on the Transport Properties of Melt-Spun Sb2−x Bi x Te3+y .

International audienceIn this work, we present our attempt to improve the thermoelectric performance of melt-spun (MS) Sb2−x Bi x Te3+y samples densified by spark plasma sintering (SPS) through two different methods: (1) alignment of the MS ribbons in the SPS die; (2) repetitive SPS sintering. A microstructural study of the dense samples was performed by scanning electron microscopy supported by x-ray diffraction analyses. The thermoelectric and galvanomagnetic properties were measured in the direction perpendicular to the uniaxial pressing direction of SPS. Alignment of the ribbons gives rise to improved thermoelectric performances with an increase of up to 26% with respect to the reference sample, yielding a peak dimensionless figure of merit ZT value of 1.1 at 355 K. Yet, in contrast to recent studies, we observed a decrease in the thermoelectric efficiency of ∼10% in the Sb1.5Bi0.5Te3.1 sample prepared by double-SPS compared to the sample densified with a single SPS process. Nevertheless, all MS samples possess improved thermal and electrical properties compared to the reference samples, proving the positive influence of this method

Application du plasma atmosphérique froid en oncologie : une revue systématique

Introduction : Le plasma atmosphérique froid est un gaz ionisé produit à pression atmosphérique. Plusieurs applications médicales sont étudiées, notamment la cicatrisation des plaies chroniques et l’effet antimicrobien. En effet, le traitement par plasma permet de générer de nombreuses espèces réactives de l’oxygène et de l’azote. L’application d’un tel traitement in-vitro sur des cellules eucaryotes a montré de nombreux effets cellulaires tel que l’apoptose. Les applications dans le domaine de l’oncologie ont par conséquent été étudiées. Objectif : L’objectif de cette revue systématique est d’analyser l’utilisation du plasma atmosphérique froid en oncologie ainsi que les méthodologies (lignées cellulaires ciblées, paramètres physiques, thérapies directes ou indirectes) mises en oeuvre jusqu’à ce jour. Matériels et méthodes : Les bases de données Pubmed, ICTRP et Google Scholar ont été explorées jusqu’au 17/01/2017 afin de recenser les études traitant de l’utilisation du plasma en oncologie, que ce soit des études in-vitro, in-vivo ou des essais cliniques. Résultats : 150 articles originaux ont été inclus. Les Jets de plasma sont les systèmes de production de plasma les plus utilisés (73,3%). L’hélium est le gaz le plus utilisé (34%) suivi par l’air (28%) et l’argon (19,3%). Les études sont principalement in-vitro (94%). L’application directe du plasma est la plus représentée (84,2%). Les lignées cellulaires ciblées sont la plupart dérivées de lignées cancéreuses humaines (82%), en particulier des lignées issues de cancer du cerveau (16,6%). Conclusions : Cette étude met en évidence la multiplicité de moyens de production et d’applications clinques du plasma atmosphérique froid en oncologie. Alors que certains dispositifs peuvent être utilisés directement sur les patients, d’autres ouvrent la voie au développement de nouveaux produits pharmaceutiques qui pourraient être produits à échelle industrielle. L’utilisation clinique du plasma nécessite la mise au point de protocoles fiables et standardisés afin de déterminer le plasma le plus adapté à chaque type de cancers et d’envisager son association avec les traitements conventionnels

J Clin Periodontol

AIM: To assess whether periodontal treatment can lead to clinical, glycaemic control and quality of life improvements in metabolically unbalanced diabetic patients (type 1 or type 2) diagnosed with periodontitis. METHODS: In this open-labelled randomized controlled trial, diabetic subjects (n = 91) were given "immediate" or "delayed" periodontal treatment (full-mouth non-surgical scaling and root planing, systemic antibiotics, and oral health instructions). The main outcome was the effect on glycated haemoglobin (HbA1C ) and fructosamine levels. The General Oral Health Assessment Index and the SF-36 index were used to assess quality of life (QoL). RESULTS: Periodontal health significantly improved after periodontal treatment (p < 0.001). Periodontal treatment seemed to be safe but had no significant effects on glycaemic control based on HbA1C (adjusted mean difference with a 95% confidence interval (aMD) of 0.04 [-0.16;0.24]) and fructosamine levels (aMD 5.0 [-10.2;20.2]). There was no obvious evidence of improvement in general QoL after periodontal treatment. However, there was significant improvement in oral health-related QoL (aMD 7.0 [2.4;11.6], p = 0.003). CONCLUSION: Although periodontal treatment showed no clinical effect on glycaemic control in this trial, important data were provided to support periodontal care among diabetic patients. Periodontal treatment is safe and improves oral health-related QoL in patients living with diabetes. ISRCTN15334496

High-resolution solid state NMR experiments for the characterization of calcium phosphate biomaterials and biominerals

Calcium phosphates form a vast family of biominerals, which have attracted much attention in fields like biology, medicine, and materials science, to name a few. Solid state Nuclear Magnetic Resonance (NMR) is one of the few techniques capable of providing information about their structure at the atomic level. Here, examples of recent advances of solid state NMR techniques are given to demonstrate their suitability to characterize in detail synthetic and biological calcium phosphates. Examples of high-resolution 31P, 1H (and 17O), solid state NMR experiments of a 17O-enriched monocalcium phosphate monohydrate-monetite mixture and of a mouse tooth are presented. In both cases, the advantage of performing fast Magic Angle Spinning NMR experiments at high magnetic fields is emphasized, notably because it allows very small volumes of sample to be analyzed