Interfacial thermal resistance measurement between metallic wire and polymer in polymer matrix composites

The addition of thermally conductive particles is an effective way to increase thermal conductivity of polymers. For highly filled composites and therefore for a high effective thermal conductivity, the heat transfer at the matrix/particle interface becomes a key point to obtain further improvement. However the interfacial thermal resistance R_i between particles and matrix is difficult to measure because of the low sensitivity of temperature to R_i and because of the small size of the particles. A setup has been developed to measure R_i between nickel wires (fiber-like particles) of a few tens micrometer diameter and a polymer matrix. The temperature measurement of the heating wire associated with a thermal model allowed to estimate values of R_i between 0.3 × 10⁻⁵ and 1.6 × 10⁻⁵ m² K W⁻¹ and for various wire diameters and sample temperatures. Some R_i measurements have been validated using a thermo-elastic model.     

Development of an experimental technique to assess the permeability of metal coated polymer films

The experimental time required to measure water vapour permeability of barrier film using the cup method is extremely long. In this study, a new technique is proposed, based on light transmission. This fast and accurate method was first validated using model films constituted of aluminized PET (polyethylene terephthalate) with aluminium layers of different thicknesses (<100 nm). It was possible to show that the ‘illuminating’ method could advantageously be employed to control the film’s barrier properties during their fabrication. In a second step, the method was tentatively used to measure the changes in barrier properties over time, when the samples are submitted to severe hydrothermal ageing (70 °C, 90% relative humidity [RH]). It was concluded that the complex degradation mechanism prevents accurate measurement while ageing.     

Characterization of archaeological beeswax by electron ionization and electrospray ionization mass spectrometry

To better detect and identify beeswax in ancient organic residues from archaeological remains, we developed a new analytical methodology consisting of the analysis of (i) the trimethylsilylated organic extract by GC/MS and (ii) the crude extract by ESI-MS. Selective scanning modes, such as SIM or MRM, permit separate quantification of each chemical family (fatty acids, monoesters, monohydroxyesters, and diesters) and allow an improvement in sensitivity and selectivity, allowing the crude extract to be treated without further purification. GC/MS (SIM) was revealed to be a powerful method for the detection of components, with a detection limit down to a total lipid extract in the range of approximately 50 ng in a complex matix, such as archaeological degraded material, whereas ESI-MS/MS is instead used for the detection of nonvolatile biomarkers. Identification by GC/MS (SIM) and ESI-MS/ MS (MRM) of more than 50 biomarkers of beeswax in an Etruscan cup at the parts-per-million level provides the first evidence for the use of this material by the Etruscans as fuel or as a waterproof coating for ceramics.     

Isolated premature breast development in young girls. Results of the LH-RH test

Thirty-six cases of premature thelarche in girls 9 months to 7 years old have been studied. In most cases, breast development began before 3 years and came to regression. Onset after 3 years was less common and led usually to breast persistance. Height was lightly but significantly advanced. Plasma levels of estrone, estradiol (in 21 cases) and gonadotropins (FSH and LH, in 12 cases) were not significantly increased. However, LH-RH test (in 12 cases) suggested prolongation and/or increase of the physiologic gonadotropic hyperactivity of normal female infants.     

Iterative construction of Dupin cyclide characteristic circles using non-stationary Iterated Function Systems (IFS)

A Dupin cyclide can be defined, in two different ways, as the envelope of an one-parameter family of oriented spheres. Each family of spheres can be seen as a conic in the space of spheres. In this paper, we propose an algorithm to compute a characteristic circle of a Dupin cyclide from a point and the tangent at this point in the space of spheres. Then, we propose iterative algorithms (in the space of spheres) to compute (in 3D space) some characteristic circles of a Dupin cyclide which blends two particular canal surfaces. As a singular point of a Dupin cyclide is a point at infinity in the space of spheres, we use the massic points defined by Fiorot. As we subdivide conic arcs, these algorithms are better than the previous algorithms developed by Garnier and Gentil.     

Assessing the effect of nutrient mitigation measures in the watersheds of the Southern Bight of the North Sea

The Seine, Somme, and Scheldt Rivers (France, Belgium, and Netherlands) are the major delivering rivers flowing into the continental coastal zone of the Southern Bight of the North Sea, an area regularly affected by eutrophication problems. In the present work, the Seneque-Riverstrahler model was implemented in a multi-regional case study in order to test several planned mitigation measures aimed at limiting stream nutrient contamination and restoring balanced nutrient ratios at the coastal zone.This modeling approach, which is spatially distributed at the basin scale, allows assessing the impact of any change in human activities, which widely differ over the three basins. Here, we define realistic scenarios based on currently proposed measures to reduce point and non-point sources, such as the upgrading of wastewater treatment, the introduction of catch crops, and the development of extensive farming. An analysis of the current situation showed that a 47-72% reduction in P point-source emissions within the three basins could be reached if the intended P treatment was generalized to the largest treatment plants. However, only an overall 14-23% reduction in N could be achieved at the outlet of the three basins, by combining improved wastewater treatment and land use with management measures aimed at regulating agricultural practices. Nonetheless, in spite of these efforts, N will still be exported in large excess with respect to the equilibrium defined by the Redfield ratios, even in the most optimistic hypothesis describing the long-term response of groundwater nitrate concentrations.A comprehensive assessment of these mitigation measures supports the need for additional reductions of nutrient losses from agriculture to control harmful algae development. It also stresses the relevance of this mechanistic approach, in which nutrient transfers from land to sea can be calculated, as an integrated strategy to test policy recommendations.     

A New Transient Two-Wire Method for Measuring the Thermal Diffusivity of Electrically Conducting and Highly Corrosive Liquids Using Small Samples

The transient hot-wire (THW) technique is widely used for measurements of the thermal conductivity of most fluids, and some attempts have also been carried out for simultaneous measurements of the thermal diffusivity with the same hot wire. However, for some particular liquids like concentrated nitric acid solutions or similar nitric mixtures, for which the thermal properties are important for industrial or security applications, this technique may be difficult to use, because of possible technological incompatibilities between measurement probe materials and highly electrically conducting and corrosive liquids. Moreover, the possible highly energetic (explosive) character of these liquids requires minimum volume liquid samples and safety measurement devices and processes. It is the purpose of this paper to report on a modified THW technique (previously used for thermal-diffusivity measurements in soils), which is associated with a specific patented double-wire probe and is shown to be valid for direct thermal-diffusivity measurements in liquids. This method responds to the previous requirements and allows automatic and quasi-simultaneous thermal-conductivity and thermal-diffusivity measurements to be made safely on liquids compatible with the tantalum technology, with liquid sample volumes < 2 cm³. Low uncertainties are found for the thermal-diffusivity data when relative measurements are carried out with reference liquids like water or toluene.