Advances in Development of Quartz Crystal Oscillators at Liquid Helium Temperatures

This work presents some recent results in the field of liquid helium {bulk acoustic wave} oscillators. The discussion covers the whole development procedure starting from component selection and characterization and concluding with actual phase noise measurements. The associated problems and limitations are discussed. The unique features of obtained phase noise power spectral densities are explained with a proposed extension of the Leeson effect.Comment: Cryogenics, 201

Paysage urbain et rural à Limoux d'après une source méconnue : le terrier royal de 1316

Throughout XIIIe century, the town of Limoux (Aude) radically changed. The Albigensian crusade has for consequence to modify urban space. But it is also the fruit of the economic growth and large trade. Limoux did not see only drapery, but makes also vigorous great strides of the work of skins and of leathers. A new document restores part of the face of the city and its territory at the beginning of XIVe century: the royal terrier of 1316 whose copy of the XVIIIe century is preserved at the Archives Nationales.Tout au long du XIIIe siècle, la ville de Limoux (Aude) a profondément changé. La croisade albigeoise a pour conséquence de modifier l'espace urbain. Mais c'est aussi le fruit de la croissance économique et du grand commerce. Limoux ne vit pas seulement de la draperie, mais connaît aussi un vigoureux essor du travail des peaux et des cuirs. Un document inédit restitue une partie du visage de la ville et de son territoire au début du XIVe siècle : le terrier royal de 1316 dont une copie du XVIIIe siècle est conservée aux Archives Nationales

XI. On the theory of the structure of crystals

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Extremely Low Loss Phonon-Trapping Cryogenic Acoustic Cavities for Future Physical Experiments

Low loss Bulk Acoustic Wave devices are considered from the point of view of the solid state approach as phonon-confining cavities. We demonstrate effective design of such acoustic cavities with phonon-trapping techniques exhibiting extremely high quality factors for trapped longitudinally-polarized phonons of various wavelengths. Quality factors of observed modes exceed 1 billion, with a maximum $Q$-factor of 8 billion and $Q\times f$ product of $1.6\cdot10^{18}$ at liquid helium temperatures. Such high sensitivities allow analysis of intrinsic material losses in resonant phonon systems. Various mechanisms of phonon losses are discussed and estimated

Mass transfer and hydrodynamic characteristics of new carbon carbon packing: Application to CO2 post-combustion capture

A novel structured packing, the 4D packing, has been characterized in terms of hydrodynamics, effective area and gas side mass transfer coefficient. The increase of the 4D opening fraction allows to reduce pressure drop and to get a better capacity than Mellapak 500Y and 750Y, for which the geometric areas are similar. The 50% open 4D packing, 4D-50%, leads to effective areas which are higher than Mellapak 500Y ones, and doubled compared with Mellapak Plus 252Y ones. Effective areas for the 4D do not decrease when the opening fraction increases from 30 to 50%, this indicates that a non-negligible amount of droplets is generated at 50%. Gas side mass transfer coefficient had been measured with an original experimental method: water evaporation. Corresponding results seem to be in agreement with the literature, and with the fact that a large amount of droplets is generated. Correlations are proposed for both effective area and gas side mass transfer coefficient for the 4D-50%.The 4D-50% packing could be very interesting for post-combustion CO2 capture since it generates low pressure drop and a very high interfacial area. This will be further confirmed by an economic study for which the absorber plant will be designed with a rate based model

L'eau et la terre. Les transformations des milieux humides en Languedoc-Roussillon au Moyen Âge

The landscapes and the new parcels resulting from the draining of the ponds result from an action on the very long term, since Antiquity at our days. As well in Languedoc as in all Europe, the behavior of the populations is of the economic situation, answers different choices following the moment and the place, takes into account factors economic, social and probably such natural, bioclimatic and hydrological in particular. During the Middle Ages, the behaviors strongly appear to have evolved/moved. The drainage of the ponds is at the origin of an original landscape whose print is always quite visible today and constitutes a heritage of the medieval centuries whose patrimonial quality deserves to be taken into account.Les paysages et les nouveaux parcellaires issus de l'assèchement des étangs résultent d'une action sur le très long terme, depuis l'Antiquité à nos jours. Aussi bien en Languedoc que dans toute l'Europe, le comportement des populations est conjoncturel, répond à des choix différents suivant le moment et le lieu, prend en compte des facteurs économiques, sociaux et probablement aussi naturels, bioclimatiques et hydrologiques en particulier. Pendant le Moyen Âge, les comportements paraissent avoir fortement évolué. Le drainage des étangs est à l'origine d'un paysage original dont l'empreinte est toujours bien visible aujourd'hui et constitue un héritage des siècles médiévaux dont la qualité patrimoniale mérite d'être prise en compte

Performance characteristics of a new structured packing

A new structured packing using carbon fibres, called Sepcarb® 4D, is presented. This packing has several attractive properties, such as high voidage (ε=94%) and high effective area (a=420 m2 m−3). These properties are advantageous for packing used as a gas–liquid contactor for separation units. To determine the internal characteristics of this packing, we performed several experiments using a 150-mm-internal-diameter column. Firstly, hydrodynamics experiments were conducted using an air–water counter current flow to determine the pressure drop (for both dry and wet packing) and flooding point. Secondly, the mass transfer efficiency was determined in terms of HETP (height equivalent to theoretical plate) by total reflux experiments with an n-heptane/cyclohexane mixture at atmospheric pressure. Hydrodynamic performance and mass transfer efficiency were compared with those of packings generally used in distillation and absorption

Contribution de l’Autonomisation des Femmes au Développement Humain dans l’UEMOA

L’objectif de cette étude est de vérifier l’existence d’un lien entre l’autonomisation des femmes et le développement humain dans les pays de la zone UEMOA. Pour ce faire, l’analyse est basée sur la Méthode des Moments Généralisés (MMG) appliquée aux huit (08) pays de l’UEMOA sur la période de 2001–2015 en données de panel. Les résultats mettent en évidence que la population active féminine, l’inscription des filles à l’école secondaire et la participation des femmes parlementaires agissent positivement et significativement sur l’IDH, ce qui contribuerait à une amélioration du développement humain. Par ailleurs cet article montre que l’indice d’inégalités de genre agit également positivement et non significativement sur l’IDH. Ainsi, cette étude suggère qu’une réduction de l’indice d’inégalités de genre pourrait agir de manière significative sur l’Indice du Développement Humain. This paper focuses on verifying the existence of a link between the empowerment of women and human development in countries of the WAEMU zone. To do this, the analysis is based on the Generalized Moment Method (GMM) applied to the eight (8) WAEMU countries over the period 2001–2015 in panel data. The results show that the female workforce, the enrolment of girls in secondary school, and the participation of women parliamentarians have a positive and significant impact on the HDI, contributing to an improvement in human development. This paper further shows that the gender inequality index also acts positively and not significantly on the HDI. This study suggests that a reduction in the index of gender inequalities could have a significant effect on the Human Development Index