Determination of the color temperature in laser-produced shocks

Experimental results on the determination of the color temperature in shock waves produced with lasers are presented. The method is based on imaging the target rear side in two different spectral windows and on using phased zone plates to produce high-quality shocks. The shock velocity is also measured, allowing, with the use of the equation of state, the real shock temperature to be deduced and compared with the measured color temperature

Cristal trapézoïdal en spectroscopie X d'implosion par laser

Elastically bent, trapezoidal crystals for Bragg diffraction of X-rays allow designing broadband spectrometers with flat field, normal incidence and high resolution. This is applied to study microballoon implosions driven by six laser beams.En courbant élastiquement un cristal trapézoïdal pour la diffraction de Bragg des rayons X, on réalise un spectrographe à champ plan, large bande et haute résolution, sous incidence normale. Grâce à lui, on étudie des implosions de microballons par un laser à six faisceaux

Synthesis And Thermal Characterization Of Polypropylene/Aluminum Composites

The present work investigates the heat transfer and specifically, thermal conductivity, diffusivity and specific heat in Aluminium composite materials. The composites were obtained by mixing polypropylene (PP) with oxidized Aluminium (Al) under various volume fractions. Two sizes of filler are used in the sample composite preparation. A nonlinear least-square criterion is used on experimental transfer functions to identify the thermal conductivity and the diffusivity of polypropylene/Aluminium (PP/Al) composites. The thermal parameters of the PP/Al composites having two sizes were determined through identification procedure. Then the density measurements were also carried out in order to deduce the specific heat and thereafter they were compared to values given by differential scanning calorimetry (DSC) measurement. The theoretical results are compared with the experimental ones. Both the Agari and Bruggeman models provide a good estimation for thermal conductivity. Both thermal conductivity and diffusivity show a better heat transport for the composite having large particles, and the heat transfer in this case combine the contribution of phonon and electron transport mode. KEY WORDS: Thermal properties, polypropylene/Aluminium, material composites. Global Journal of Pure and Applied Sciences Vol.11(1) 2005: 63-7

Thermophysical properties of ethylene-vinyl acetate copolymer (EVA) filled with wollastonite fibers coated by silver

A new type of thermally conductive fibers based on silver coated wollastonite was prepared and characterized. The fibers were used for the preparation of elastic, highly thermally conductive polymeric composites based on ethylene-vinylacetate copolymer (EVA). It was shown that silver coated fibers significantly improved the thermal conductivity of composites despite the low silver volume content. The experimental results were discussed and compared to various theoretical models. The specific heat and the specific density of the composites were also characterized and reported. (c) 2008 Elsevier Ltd. All rights reserved

Thermophysical and Electrical Properties of Nanocomposites Based on Ethylene-Vinylacetate Copolymer (EVA) Filled with Expanded and Unexpanded Graphite

Over the last few years, conducting polymer/graphite nanocomposites have attracted considerable interest because of their exceptional electrical, thermal, and mechanical properties. Polymeric nanocomposites prepared from high aspect ratio layered graphite nanofillers achieve significant improvements in thermophysical and electrical properties at low filler concentrations, compared to conventional composites, without a significant increase in density. In this work, various aspects of the electrical and thermophysical behavior of nanocomposites are presented based on the ethylene-vinylacetate matrix filled with nanostructured expanded graphite and standard, (nano)/micro-sized graphite

Fate of carbamazepine and anthracene in soils watered with UV-LED treated wastewaters

International audienceWater disinfection technologies based on ultraviolet (UV) radiations emitted by Light-Emitting Diodes (LED), as a wastewater tertiary treatment, have been shown to be promising for water reuse. Here, we assessed the fate of two ubiquitous pollutants, carbamazepine and anthracene, in soil watered with either UV-LED treated wastewaters or irrigation water. After 3 months, anthracene and carbamazepine were transformed two and three times faster respectively, in soils watered with UV-LED wastewater than in soils watered with tap water (probably because of the addition of organic matter by the effluent). Laccase activity was induced in the presence of the pollutants and anthraquinone was found as anthracene product of oxidation by laccases. Moreover, the addition of these pollutants into soil did not affect the functional diversity of autochthonous microbial communities assessed by Ecolog plates. Cellulase, protease and urease activities increased in soils watered with UV-LED treated wastewaters (UV-LED WW), showing transformation of organic matter from the effluent and lipase activity increased by anthracene addition, confirming the potential role of these enzymes as indicators of hydrocarbon contamination

Unconventional experimental technologies used for phase change materials (PCM) characterization: Part 2 - Morphological and structural characterization, physico-chemical stability and mechanical properties

Due to the high interest of appropriate characterization of PCM and hybrid PCM composites, different research centres and universities are using several material characterization techniques not commonly used with PCM, to study the structure and morphology of these materials. Likewise, physico-chemical stability is a crucial parameter for the performance of latent storage materials during time and its evaluation has been done by using molecular spectroscopy, chemiluminiscence or calorimetric tests. Atomic force microscopy and nanoindentation are also reported to characterize hybrid PCM composites. Other chemical aspects studied are related with the compatibility of the PCM and its container and also considered in this compilation of characterization work. ©2014 Elsevier Ltd. All rights reserved.Departament d'Universitats, Recerca i Societat de la Informació ENE2011-28269-C03-01, ENE2011-22722, ENE2011-28269-C03-02 European Commission COST TU0802The work is partially funded by the European Union (COST Action COST TU0802 ) and the Spanish government ( ENE2011-28269-C03-01 , ENE2011-28269-C03-02 and ENE2011-22722 ). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA ( 2014 SGR 123 ) and their research group DIOPMA ( 2014 SGR 1543 ). Aran Solé would like to thank the Departament d’Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for her research fellowship

Impact of watering with UV-LED-treated wastewater on microbial and physico-chemical parameters of soil

International audienceSoil microbial activity Faecal indicator Catabolic activity Enzymatic activities a b s t r a c t Advanced oxidation processes based on UV radiations have been shown to be a promising wastewater disinfection technology. The UV-LED system involves innovative materials and could be an advantageous alternative to mercury-vapor lamps. The use of the UV-LED system results in good water quality meeting the legislative requirements relating to wastewater reuse for irrigation. The aim of this study was to investigate the impact of watering with UV-LED treated wastewaters (UV-LED WW) on soil parameters. Solid-state 13 C NMR shows that watering with UV-LED WW do not change the chemical composition of soil organic matter compared to soil watered with potable water. Regarding microbiological parameters, laccase, cellulase, protease and urease activities increase in soils watered with UV-LED WW which means that organic matter brought by the effluent is actively degraded by soil microorganisms. The functional diversity of soil microorganisms is not affected by watering with UV-LED WW when it is altered by 4 and 8 months of watering with wastewater (WW). After 12 months, functional diversity is similar regardless of the water used for watering. The persistence of faecal indicator bacteria (coliform and enterococci) was also determined and watering with UV-LED WW does not increase their number nor their diversity unlike soils irrigated with activated sludge wastewater. The study of watering-soil microcosms with UV-LED WW indicates that this system seems to be a promising alternative to the UV-lamp-treated wastewaters.