Sample records for hollandite verre son68

  1. (Alpha, gamma) irradiation effect on the alteration of high-level radioactive wastes matrices (UO{sub 2}, hollandite, glass SON68); Effet de l'irradiation (alpha, gamma) sur l'alteration des matrices de dechets nucleaires de hautes activites (UO{sub 2}, hollandite, verre SON68)

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    Suzuki, T


    The aim of this work is to determine the effect of irradiation on the alteration of high level nuclear waste forms matrices. The matrices investigated are UO{sub 2} to simulate the spent fuel, the hollandite for the specific conditioning of Cs, and the inactive glass SON68 representing the nuclear glass R7T7) The alpha irradiation experiments on UO{sub 2} colloids in aqueous carbonate media have enabled to distinguish between the oxidation of UO{sub 2} matrix as initial and dissolution as subsequent step. The simultaneous presence of carbonate and H{sub 2}O{sub 2} (product resulting from water radiolysis) increased the dissolution rate of UO{sub 2} to its maximum value governed by the oxidation rate. ii) The study of hollandite alteration under gamma irradiation confirmed the good retention capacity for Cs and Ba. Gamma irradiation had brought only a little influence on releasing of Cs and Ba in solution. Electronic irradiation had conducted to the amorphization of the hollandite only for a dose 1000 times higher than the auto-induced dose of Ba over millions of years. iii) The experiences of glass irradiation under alpha beam and of helium implantation in the glass SON68 were analyzed by positon annihilation spectroscopy. No effect has been observed on the solid surface for an irradiation dose equal to 1000 years of storage. (author)

  2. Compared study of the local structure of alteration products of SON 68 glass and natural gels; Etude comparee de la structure locale des produits d'alteration du verre SON 68 et de gels naturels

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    Pellegrin, E


    This study is a contribution in the understanding of the long time behavior of alteration products of the glass SON 68, used to simulate the nuclear glass R7T7. The local structure around Zirconium and iron has been probed using X-ray absorption spectroscopy in altered surface layer of glass SON 68. Alteration products of this glass have been prepared for short (3 hours to 7 days) and long (17 months) time, using various indexes of saturation for the leaching solution with respect to the Si content of the glass (from 0 to 90 %). The evolution of the local structure around Fe has also been studied in recent and old natural ferric gels. Zr, Fe- L{sub 2,3} XANES and Zr, Fe-K EXAFS spectroscopies have shown that, in the pristine glass, these elements are connected to the polymeric network. Zr is found in an environment close to that of a zircon-silicate containing Na and Ca. Trivalent Fe is a network former. The leached layer of glass SON 68 is constituted of poorly ordered Zr-and Fe-(oxi-hydr)oxides that may have been formed by a mechanism of dissolution/precipitation; a relict phase with the same Zr local structure as that observed in the pristine glass, probably obtained thanks to in-situ solid condensation. The structural characteristics of the leached layer are observed from the first steps of alteration for Zr and Fe. Conversely to Fe, the structural status of Zr depends on the leaching kinetic as well as the contents of Ca and Si in the solid. Fe-K EXAFS results in recent natural ferri-hydrides present a clear structural similarity with that determined in glass SON 68 leached products. The study of old paleosols (between 1,800 and 200,000 years) has demonstrated the long time stability of ferric gels, although an increase of medium range order around Fe is seen. (author)

  3. Isotope tracing ({sup 29}Si and {sup 18}O) of the alteration mechanisms of the French glass 'SON68' used for the storage of nuclear waste; Tracage isotopique ({sup 29}Si and {sup 18}O) des mecanismes de l'alteration du verre de confinement des dechets nucleaires: 'SON68'

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    Valle, N


    This study aims to enhance our understanding of the mechanisms of aqueous corrosion of the glasses used for the storage of nuclear waste. Glass samples 'SON68', doped with a different rare earth element (La, Ce or Nd), were altered simultaneously with water enriched in {sup 29}Si and {sup 18}O, throughout a period of 20 months. The aim of such isotope tracing was (i) to follow the 'real' exchanges between glass and solution and (ii) to understand the reactions involving Si-O bonds in the leached layer during alteration. Leachates were analyzed by ICP-MS and -AES, and elemental and isotopic variations in the altered glass layer were measured by ion-probe, using a depth profiling technique. Elemental analyses enabled the distribution of the elements in the two layers of altered glass (phyllosilicates and gel) to be established, and the results reveal a selective partitioning of elements between the two layers. Isotopic analyses of altered layers and leachates allowed phyllosilicates to be distinguished from gel, and suggest two different mechanisms of formation. Whilst phyllosilicates grow on the surface of the glass by a mechanism of precipitation, gel is formed by a succession of hydrolysis / condensation reactions taking place mainly at the gel / pristine glass interface. This gel is formed by the in situ rearrangement of hydrated species, without reaching equilibrium with the solution. Moreover, an experimental technique has been developed enabling one to trace the transport of silicon from the solution into the altered glasses, under an isotopic gradient. Diffusion profiles, obtained by ion-probe, have been modeled and have allowed the determination of the apparent silicon diffusion coefficient (DSi) in gels. Therefore, our experiments have permitted the quantification of the influence of both the alteration conditions (dynamic or static tests) and the solution composition on the value of DSi. (author)

  4. SON68 glass dissolution driven by magnesium silicate precipitation

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    Fleury, Benjamin, E-mail: [CEA Marcoule, DEN/DTCD/SECM/LCLT, BP17171, 30207 Bagnols-sur-cèze (France); Godon, Nicole [CEA Marcoule, DEN/DTCD/SECM/LCLT, BP17171, 30207 Bagnols-sur-cèze (France); Ayral, André [IEM, University Montpellier 2, CC 047, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France); Gin, Stéphane [CEA Marcoule, DEN/DTCD/SECM/LCLT, BP17171, 30207 Bagnols-sur-cèze (France)


    Experimental results are reported on the effect of magnesium silicate precipitation on the mechanisms and rate of borosilicate glass dissolution. Leaching experiments with SON68 glass, a borosilicate containing no Mg, were carried out in initially deionized water at 50 °C with a glass-surface-area-to-solution-volume ratio of 20,000 m{sup −1}. After 29 days of alteration the experimental conditions were modified by the addition of Mg to trigger the precipitation of Mg-silicate. Additional experiments were conducted to investigate the importance of other parameters such as pH or dissolved silica on the mechanisms of precipitation of Mg-silicates and their consequences on the glass dissolution rate. Mg-silicates precipitate immediately after Mg is added. The amount of altered glass increases with the quantity of added Mg, and is smaller when silicon is added in solution. A time lag is observed between the addition of magnesium and the resumption of glass alteration because silicon is first provided by partial dissolution of the previously formed alteration gel. It is shown that nucleation does not limit Mg-silicate precipitation. A pH above 8 is necessary for the phase to precipitate under the investigated experimental conditions. On the other hand the glass alteration kinetics limits the precipitation if the magnesium is supplied in solution at a non-limiting rate.

  5. SON68 glass dissolution driven by magnesium silicate precipitation (United States)

    Fleury, Benjamin; Godon, Nicole; Ayral, André; Gin, Stéphane


    Experimental results are reported on the effect of magnesium silicate precipitation on the mechanisms and rate of borosilicate glass dissolution. Leaching experiments with SON68 glass, a borosilicate containing no Mg, were carried out in initially deionized water at 50 °C with a glass-surface-area-to-solution-volume ratio of 20,000 m-1. After 29 days of alteration the experimental conditions were modified by the addition of Mg to trigger the precipitation of Mg-silicate. Additional experiments were conducted to investigate the importance of other parameters such as pH or dissolved silica on the mechanisms of precipitation of Mg-silicates and their consequences on the glass dissolution rate. Mg-silicates precipitate immediately after Mg is added. The amount of altered glass increases with the quantity of added Mg, and is smaller when silicon is added in solution. A time lag is observed between the addition of magnesium and the resumption of glass alteration because silicon is first provided by partial dissolution of the previously formed alteration gel. It is shown that nucleation does not limit Mg-silicate precipitation. A pH above 8 is necessary for the phase to precipitate under the investigated experimental conditions. On the other hand the glass alteration kinetics limits the precipitation if the magnesium is supplied in solution at a non-limiting rate. The concentration of i in solution was analyzed as well as that of boron. The quantity of i released from the glass is estimated with the assumption that i and B are released congruently at the glass dissolution front. The remained quantity of the element i is then supposed to be in the gel or in the secondary phase. In this paper, we do not make a difference between gel and hydrated glass using the same word 'gel' whereas Gin et al. [40] makes this difference. Recent papers [40,41] discussed about different key issues related to the passivation properties of the alteration layer including the hydrated glass

  6. Helium mobility in SON68 borosilicate nuclear glass: A nuclear reaction analysis approach

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    Bès, R., E-mail: [CNRS, UPR3079 CEMHTI, 1D Avenue de la Recherche Scientifique, 45071 Orléans cedex 2 (France); Sauvage, T. [CNRS, UPR3079 CEMHTI, 1D Avenue de la Recherche Scientifique, 45071 Orléans cedex 2 (France); Université d’Orléans, Faculté des Sciences, Avenue du Parc Floral, BP 6749, 45067 Orléans cedex 2 (France); Peuget, S. [CEA/DEN/VRH/DTCD/SECM/LMPA Marcoule (France); Haussy, J. [CEA, DAM, DIF, F-91297 Arpajon (France); Chamssedine, F. [Université Libanaise, Faculté des Sciences V, Nabatiyeh (Lebanon); Oliviero, E. [CSNSM, CNRS/IN2P3 and Université Paris-Sud, Bât. 104-108, F-91405 Orsay (France); Fares, T. [CEA/DEN/VRH/DTCD/SECM/LMPA Marcoule (France); Vincent, L. [Institut d’Electronique Fondamentale, CNRS and Université Paris-Sud, UMR 8622, F-91405 Orsay (France)


    The {sup 3}He behavior in the non active R7T7 type borosilicate glass called SON68 has been investigated using the implantation method to introduce helium in the material. Nuclear Reaction Analysis (NRA) was performed to follow the helium concentration depth profile evolution as a function of annealing time and temperature. In addition, in situ Transmission Electron Microscopy (TEM) has been implemented to study the formation of helium bubbles during both implantation and annealing processes. Numerical modeling with two different approaches is proposed and discussed to investigate the helium mobility mechanisms. Our study reveals for helium incorporation by implantation at low temperature the presence of several helium populations with disparate diffusivities. The most mobile helium fraction would be attributed to atomic diffusion. The corresponding activation energy value (0.61 eV) extracted from Arrhenius graphs is in good agreement with literature data. The results also highlight that the damages associated to helium sursaturation are the source of small helium clusters formation, with a reduced mobility instead of the atomic mobility measured by the infusion technique. Small cavities that support this assumption have been observed by TEM at low temperature.

  7. Effect of Callovo-Oxfordian clay rock on the dissolution rate of the SON68 simulated nuclear waste glass (United States)

    Neeway, James J.; Abdelouas, Abdesselam; Ribet, Solange; El Mendili, Yassine; Schumacher, Stéphan; Grambow, Bernd


    Long-term storage of high-level nuclear waste glass in France is expected to occur in an engineered barrier system (EBS) located in a subsurface Callovo-Oxfordian (COx) clay rock formation in the Paris Basin in northeastern France. Understanding the behavior of glass dissolution in the complex system is critical to be able to reliably model the performance of the glass in this complex environment. To simulate this multi-barrier repository scenario in the laboratory, several tests have been performed to measure glass dissolution rates of the simulated high-level nuclear waste glass, SON68, in the presence of COx claystone at 90 °C. Experiments utilized a High-Performance Liquid Chromatography (HPLC) pump to pass simulated Bure site COx pore water through a reaction cell containing SON68 placed between two COx claystone cores for durations up to 200 days. Silicon concentrations at the outlet were similar in all experiments, even the blank experiment with only the COx claystone (∼4 mg/L at 25 °C and ∼15 mg/L at 90 °C). The steady-state pH of the effluent, measured at room temperature, was roughly 7.1 for the blank and 7.3-7.6 for the glass-containing experiments demonstrating the pH buffering capacity of the COx claystone. Dissolution rates for SON68 in the presence of the claystone were elevated compared to those obtained from flow-through experiments conducted with SON68 without claystone in silica-saturated solutions at the same temperature and similar pH values. Additionally, through surface examination of the monoliths, the side of the monolith in direct contact with the claystone was seen to have a corrosion thickness 2.5× greater than the side in contact with the bulk glass powder. Results from one experiment containing 32Si-doped SON68 also suggest that the movement of Si through the claystone is controlled by a chemically coupled transport with a Si retention factor, Kd, of 900 mL/g.

  8. Biological effect of Acidithiobacillus thiooxidans on some potentially toxic elements during alteration of SON 68 nuclear glass (United States)

    Bachelet, M.; Crovisier, J. L.; Stille, P.; Vuilleumier, S.; Geoffroy, V.


    Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH, with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 m french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25degC. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, trace and ultra-trace elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 m under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials are found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium as tracer, showed that the progressive formation of a biofilm on the surface of glass has a protective effect against its alteration. Uranium and rare earth elements (REE) are efficiently trapped in the biogenic compartment of the system (exopolysaccharides + bacterial cells). Besides, the ratio

  9. Frustrated Magnetism and Electronic Properties of Hollandite Oxide Materials (United States)

    Larson, Amber Marie

    Microporous transition metal oxides with the hollandite structure type have been prepared by standard solid-state techniques with varying compositions. With a nominal formula of Ax M8O16 and a framework of edge and corner-sharing MO6 octahedra, hollandites feature a pseudo-one dimensional tunnel occupied loosely by cation A. The metastability of these open-framework materials, combined with the ability of accommodating a variety of redox-active transition metals leads to unique and indispensable properties. Inherent to the triangular connectivity of the M cations in the hollandite framework, these materials frequently exhibit frustrated magnetic behavior. This thesis demonstrates that it is possible to significantly affect the magnetic and transport properties of these microporous materials through tuning of their chemical compositions. We have shown that it is possible to synthesize polycrystalline and single crystal hollandite materials under ambient conditions utilizing salt flux techniques. Our efforts to characterize the structure-property relationships provide some of the first magnetic structure determinations of these complex frameworks. The interesting behavior of these materials is a result of the interplay between charge, orbital, and spin degrees of freedom. This work shows that the hollandite framework is quite versatile, leading to the real possibility of tuning the material properties to achieve desired effects and opening up many potential applications for these microporous oxides.

  10. Radiation damage of hollandite in multiphase ceramic waste forms (United States)

    Clark, Braeden M.; Tumurgoti, Priyatham; Sundaram, S. K.; Amoroso, Jake W.; Marra, James C.; Shutthanandan, Vaithiyalingam; Tang, Ming


    Radiation damage was simulated in multiphase titanate-based ceramic waste forms using an ion accelerator to generate high energy alpha particles (He+) and an ion implanter to generate 7 MeV gold (Au3+) particles. X-ray diffraction and transmission electron microscopy were used to characterize the damaged surfaces and nearby regions. Simulated multiphase ceramic waste forms were prepared using two processing methods: spark plasma sintering and melt-processing. Both processing methods produced ceramics with similar phase assemblages consisting of hollandite-, zirconolite/pyrochlore-, and perovskite-type phases. The measured heavy ion (Au3+) penetration depth was less in spark plasma sintered samples than in melt-processed samples. Structural breakdown of the hollandite phase occurred under He+ irradiation indicated by the presence of x-ray diffraction peaks belonging to TiO2, BaTiO5, and other hollandite related phases (Ba2Ti9O20). The composition of the constituent hollandite phase affected the extent of damage induced by Au3+ ions.

  11. Chemical durability of hollandite ceramic for conditioning cesium (United States)

    Angeli, Frédéric; McGlinn, Peter; Frugier, Pierre


    The aqueous corrosion behavior of Cs-doped hollandite ceramic (BaCs 0.28Fe 0.82Al 1.46Ti 5.72O 16) was studied using several different static experimental protocols, with leachants of varying pH, and at different surface area to volume ratios, for periods ranging from six months to three years. All leach tests were carried out at 90 °C. X-ray diffraction (XRD) and scanning electron microscopy (SEM), coupled with energy dispersive X-ray spectroscopy (EDS), were used to characterize the surfaces of the hollandite before and after leaching. The most pronounced elemental releases, and corresponding changes to surface composition and microstructure, was evident at low pH, in particular pH 1. Cs and Ba releases were highest at low pH, with surface alteration exhibited by the formation of secondary rutile (prevalent at pH 1) and Al- and Ba-depleted hollandite (prevalent at pH 2). After rapid initial Cs release, the alteration rate was extremely low over the pH range from 2 to 10, as well as in pure water experiments with a sample-surface-area-to-solution-volume ratio ranging from 0.1 cm -1 to 1200 cm -1. The rates were about 10 -5 g m -2 d -1, corresponding to alteration thicknesses of a few nanometers per year. Higher rates (5 × 10 -3 g m -2 d -1) were observed only under very acidic conditions (pH 1). Congruency in Cs and Ba releases occurred only at pH 1, with incongruency between the two elements increasing with increasing pH. There were no apparent solubility constraints on Cs releases regardless of the SA/ V ratio, whereas geochemical modeling suggested that Ba releases could have been affected by the formation of BaCO 3, particularly at high SA/ V ratios. Extended leaching (with the leachant renewed once after 261 days of leaching) confirmed the high durability of hollandite with altered thicknesses of less than one nanometer per year over the last two years. Whilst Cs depletion of the hollandite surface was evidenced when leachates were replenished with the

  12. Experimentally determined dissolution kinetics of SON68 glass at 90 °C over a silica saturation interval: Evidence against a linear rate law (United States)

    Icenhower, Jonathan P.; Steefel, Carl I.


    Flow-through dissolution experiments were carried out on the SON68 glass—the inactive analog of the French high-level waste glass—at 90 °C and pH = 9 over a silica saturation interval [0-150 ppm Si(aq)]. Two types of specimens were subjected to dissolution studies: powders (249-150, 149-75 or 74-45 μm diameter size fractions) or monoliths (˜1 cm × 1 cm × 4 mm). At each Si concentration interval individual coupon and glass powder experiments were run at the same flow-to-surface area (q/S) conditions. Under dilute solution conditions, the dissolution rate becomes independent of q/S and define the forward rate of reaction of 0.30 g/(m2 d). Dissolution rates of powders normalized on either a geometric or a B.E.T. surface area basis were compared to rates determined on monoliths. In every case, the geometric surface area normalized rates matched those of the monoliths, conclusively showing that B.E.T. normalized rates are too low by a factor of ˜3×. In Si-free solutions changes in flow rates resulted in differences in Al released to solution (˜50 to 3140 ppb), correlating inversely with dissolution rates. Si was added to input solutions and kept constant ("direct"), but in select experiments Si concentrations were above target concentrations, and then dropped to their target values ("indirect"). Both "direct" and "indirect" Si addition experiments yielded identical dissolution rates within experimental uncertainty. Progressive addition of Si to the input solution caused a decrease in rates from 0.30 to 0.0020 g/(m2 d), or a factor of ˜150×, but the decrease is strongly non-linear with respect to Si. These data are inconsistent with simple models relating glass dissolution to the chemical affinity of reaction.

  13. Biodegradation of the french reference nuclear glass SON 68 by Acidithiobacillus thiooxidans : protective effect of the biofilm,U and REE retention (United States)

    Bachelet, M.; Crovisier, J.; Stille, P.; Boutin, R.; Vuilleumier, S.; Geoffroy, V.


    Although underground nuclear waste repositories are not expected to be favourable places for microbial activity, one should not exclude localized action of extremophilic bacteria on some materials involved in the storage concept. Among endogenous or accidentally introduced acidophiles, some are susceptible to lead to a locally drastic decreased in pH with potential consequences on materials corrosion. Experiments were performed with Acidithiobacillus thiooxidans on 100-125 μm french reference nuclear glass SON68 grains in a mineral medium under static conditions during 60 days at 25°C. Growth medium was periodically renewed and analyzed by ICP-AES and ICP-MS spectrometry for both major, traces and ultra-traces elements. Biofilm formation was evidenced by confocal laser microscopy, staining DNA with ethidium bromide and exopolysaccharides with calcofluor white. Biofilm thickness around material grains exceeded 20 μm under the chosen experimental conditions. It can be noticed that while numerous studies on biofilm formation upon interaction between Acidithiobacillus ferrooxidans and materials can be found in the literature, evidence for biofilm formation is still scarce for the case of the acidophilic bacterium A. thiooxidans. Presence of biofilm is a key parameter for material alteration at the solid/solution interface in biotic systems. Indeed, various constitutive elements of materials trapped in the polyanionic polymer of biofilm may also influence the alteration process. In particular, biofilm may reduce the alteration rate of materials by forming a protective barrier at their surface (Aouad et al., 2008). In this study, glass alteration rates, determined using strontium, molybdenum and caesium as tracers, showed that the biofilm has a protective effect against glass alteration. U and REE are efficiently trapped in the biogenic compartment of the system (exopolysaccharides (EPS) + bacterial cells). Biofilm analysis are in progress to determine whether these

  14. New phase hollandite-type VOOH quadrangular nanorods: a new smart electrical switch material. (United States)

    Wu, Changzheng; Wei, He; Ning, Bo; Yang, Jinlong; Xie, Yi


    New phase hollandite VOOH with a novel 2 x 2 octahedral molecular sieve has been successfully achieved via an ionic liquid-assisted route. Guided by the theoretical structural analysis, the unique structural characteristics of the infinitely linear V(3+)-V(3+) chains indeed lead to smart electrical switch behaviour as expected, representing the first semiconductor-insulator transition case among the hollandite-type structures.

  15. Hollandit a kryptomelan z Poniklé u Jilemnice, Česká republika

    Czech Academy of Sciences Publication Activity Database

    Jirásek, J.; Matýsek, D.; Vaculíková, Lenka; Sivek, M.

    -, č. 23 (2015), s. 1-6 ISSN 1211-0329 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : hollandite supergroup * coronadite group * mineralogy * infrared spectroscopy * Poniklá Group Subject RIV: DB - Geology ; Mineralogy

  16. Synthesis and structural and thermodynamical characterization of hollandite type material intended for the specific containment of cesium; Synthese et caracterisation de ceramiques de type hollandite destinees au conditionnement specifique du cecium

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    Leinekugel-Le-Cocq-Errien, A.Y


    This thesis deals with the characterization of the Ba{sub 1}Cs{sub 0.28}Fe{sub 0.82}Al{sub 1.46}Ti{sub 5.72}O{sub 16} hollandite envisaged for Cs containment. Techniques used are essentially classical powder XRD or synchrotron radiation at the absorption threshold of Ba and Cs, TEM and high-temperature calorimetry. Two syntheses have been studied: an alcoxide route and a dry route. After sintering, both routes lead to an incommensurate modulated tetragonal hollandite structure (space group: I4/m(00{gamma})00) with a modulation vector distribution. Before sintering, the material obtained by the alcoxide route is composed of three phases: a tetragonal hollandite like above, a monoclinic Ba-free hollandite and a weak-coherence-length phase containing only Ba. On contrary, the dry route already leads to the tetragonal hollandite at this step of the synthesis. High temperature oxide melt solution calorimetry was used to derive standard enthalpy of formation of hollandite to deduce its free enthalpy of formation. (author)



    Chaumont, C.; J. Bernier


    L'examen et l'interprétation des propriétés magnétiques de verres d'hypertrempe dans deux systèmes xFe2O3 (1-x) [BaO, B2O3] et xFe2O3 (1-x) [Li2O,B2O3] conduisent suivant la teneur en Fe2O3 à des modèles de coordination tétraédrique ou octaédrique déformés. Dans ces verres les atomes Fe3+ sont suivant les concentrations croissantes en Fe2O3 successivement -isolés, -sous forme de dimères ou trimères, -dans des clusters en interactions, -enfin dans des microcristaux.

  18. Formation of a metastable hollandite phase from amorphous plagioclase: A possible origin of lingunite in shocked chondritic meteorites (United States)

    Kubo, Tomoaki; Kono, Mari; Imamura, Masahiro; Kato, Takumi; Uehara, Seiichiro; Kondo, Tadashi; Higo, Yuji; Tange, Yoshinori; Kikegawa, Takumi


    We conducted high-pressure experiments in plagioclase with different anorthite contents at 18-27 GPa and 25-1750 °C using both a laser-heated diamond anvil cell and a Kawai-type multi-anvil apparatus to clarify the formation conditions of the hollandite phase in shocked chondritic and Martian meteorites. Lingunite (NaAlSi3O8-rich hollandite) was found first to crystallize from amorphous oligoclase as a metastable phase before decomposing into the final stable state. This process might account for the origin of lingunite found along with maskelynite in shocked chondritic meteorites. Metastable lingunite appeared at ∼20-24 GPa and ∼1100-1300 °C in laboratory tests lasting tens of minutes; however, it might also form at the higher temperatures and shorter time periods of shock events. In contrast, the hollandite phase was not observed during any stage of crystallization when using albite or labradorite as starting materials. The formation process of (Ca,Na)-hollandite in the labradorite composition found in Martian shergottites remains unresolved. The orthoclase contents of the hollandite phase both in shocked meteorites (2.4-8.2 mol%) and our oligoclase sample (3.9 mol%) are relatively high compared to the albite and labradorite samples (0.6 and 1.9 mol%, respectively). This might critically affect the crystallization kinetics of hollandite phase.

  19. The Verrès Castle Access Project

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    Tito Berti Nulli


    Full Text Available The article describes the access project of the Verrès castle, located in Aosta Valley in Italy, underlining some urban and transport planning and design elements. This project constitute in fact an interesting example of integration between transport infrastructure planning and design with urban planning strategy for tourism development. The transport infrastructure (in this case a vertical lift for tourism use has furthermore a deep attention to the landscape and social contest and a good architectural design. The Verrès castle access project represents and interesting example of sustainable mobility and of touristic area accessibility which is strong integrated with urban renewal and territorial development. The feasibility study, financed by the Verrès municipality, is part of a the INTERREG IIIA ACOLTRA Project financed by Italy and France with the aim of creating a network of transnational tourist itineraries. Through this initiative Aosta Valley and Haute-Savoy are developing a common tourism strategy that intends to promote cultural heritage and tourism mobility through the RITT (Reseaux d’Itineraires Touristiques Transfrontalieres. In this contest of intervention the study for the accessibility of the Verrès castle is inserted, with the aim of designing a mobility infrastructure for the main attraction of the valley and at the same of strengthening the appeal of tourist attraction of the whole area. The project is located in the small city of Verrés, that lies at 390m, on the banks of the river Evançon. As many of the Valdostani municipalities is characterized by several small urban centers, which are located in a around 8kmq, in a territory where live 2.700 inhabitants. The feasibility study examines three different alternative for a lift that should connect the Verrès centre with the castle. In particular different transport technology (inclined and vertical lift and several path alternatives have been evaluated. The final

  20. Maison de verre / Zonestraal. Relato de dos edificios

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    Jan Molema


    Full Text Available Desde los años sesenta del siglo XX el sanatorio Zonnestraal de Hilversum y la Maison de Verre en París han sido descritos extensamente en la literatura de la arquitectura moderna. Sin embargo, no se ha hecho ningún esfuerzo por colocarlos juntos en un mismo relato. Este ensayo es un esfuerzo para enmendar ese vacío. Ambos están relacionados íntimamente por sus autores: Bernard Bijvoet, como codiseñador de los planos de la Maison, y Johannes Duiker, quien trabajó con el anterior en los preliminares de Zonnestraal, aunque lo finalizó en solitario, al mismo tiempo que se terminó el diseño de la casa. En el trabajo se cuestiona además, ofreciendo fundadas conjeturas, la creencia establecida de que se precisó una nueva estructura metálica para sustentar la inalterada vivienda situada encima de la Maison de Verre.

  1. Lithium insertion into hollandite-type TiO{sub 2}

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    Noailles, L.D.; Johnson, C.S.; Vaughey, J.T.; Thackeray, M.M. [Argonne National Lab., IL (United States). Chemical Technology Div.


    Hollandite-type TiO{sub 2} compounds, isostructural with {alpha}-MnO{sub 2}, have been investigated as insertion electrodes for lithium batteries. Parent materials of K{sub x}Ti{sub 8}O{sub 16} (0hollandite-TiO{sub 2} contrasts strongly with {alpha}-MnO{sub 2} electrodes. The superior properties of {alpha}-MnO{sub 2} electrodes are attributed to the presence of oxygen ions, either as H{sub 2}O or Li{sub 2}O in the (2 x 2) channels; lithia-stabilized electrodes, 0.15Li{sub 2}O.MnO{sub 2}, show good cycling behavior and a rechargeable capacity of approximately 180 mA h/g. (orig.)

  2. Vitrail, verre et archéologie entre le ve et le xiie siècle

    Directory of Open Access Journals (Sweden)

    Christian Sapin


    Full Text Available Depuis longtemps, les fouilles archéologiques ont fait apparaître des fragments de verre en très grand nombre. L’intérêt des archéologues, orienté dans un premier temps vers les verres creux, se tourne de plus en plus vers les fragments de verre plat. Ceci conduit à poser de nouvelles questions sur les diverses utilisations du verre dans l’architecture, tant civile que religieuse, en particulier pour ce qui touche à la fermeture des baies ou au décor intérieur. Cette publication fait un point...

  3. Vitrail, verre et archéologie entre le ve et le xiie siècle


    Christian Sapin


    Depuis longtemps, les fouilles archéologiques ont fait apparaître des fragments de verre en très grand nombre. L’intérêt des archéologues, orienté dans un premier temps vers les verres creux, se tourne de plus en plus vers les fragments de verre plat. Ceci conduit à poser de nouvelles questions sur les diverses utilisations du verre dans l’architecture, tant civile que religieuse, en particulier pour ce qui touche à la fermeture des baies ou au décor intérieur. Cette publication fait un point...

  4. hollandite ceramics

    Indian Academy of Sciences (India)


    Thrissur, for extending the facilities to carry out this study. References. Cheary R W 1986 Acta Crystallogr. 42 229. Cheary R W and Squadrito R 1989 Acta Crystallogr. B45 205. Dubeau M L and Edgar A D 1985 Miner. Mag. 49 603. Fanchon E, Vicat J, Hodeau J L, Wolfers P, Qui D T and. Strobel P 1987 Acta Crystallogr.

  5. Cristallisation dans les verres de silicates contenant du molybdène et du phosphore (United States)

    Cousi, C.; Bart, F.; Phalippou, J.


    L'ajout de certains oxydes dans un verre initialement homogène peut entraîner des cristallisations plus ou moins importantes du mélange lors de son refroidissement. Parmi les oxydes connus pour induire de tels phénomènes dans des verres de silicates, se trouvent l'oxyde de molybdène MoO{3} et l'oxyde de phosphore P{2}O{5}. Les matériaux étudiés ici sont des verres silico-sodo-calciques auxquels ont été ajoutés MoO{3} et P{2}O{5} en quantité variable, ce qui provoque des cristallisations importantes. L'identification et la quantification des phases cristallines en présence par MEB et méthode Rietveld à partir des diffractogrammes permettent de comprendre les rôles respectifs du molybdène et du phosphore dans les phénomènes de cristallisation intervenant dans ces verres. Mots-clés: verres d'oxydes, cristallisation, diffraction des rayons X

  6. Fabrication, characterization and radiation damage stability of hollandite based ceramics devoted to radioactive immobilisation; Synthese, caracterisation et etude du comportement sous irradiation electronique de matrices de type hollandite destinees au confinement du cesium radioactif

    Energy Technology Data Exchange (ETDEWEB)

    Aubin-Chevaldonnet, V. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DETCD/SCDV), Dept. d' Etudes du Traitement et du Conditionnement des Dechets, Service de Conditionnement des Dechets et Vitrification, 30 - Marcoule (France)


    Research on treating specifically the long-lived and high level nuclear wastes, notably cesium, is currently carried out in France. Cesium immobilization in host matrices of high chemical durability constitutes the favoured option. Hollandite matrix is a good candidate because of its high cesium incorporation ability and its excellent chemical stability. During this study, different compositions of hollandite ceramics Ba{sub x}Cs{sub y}C{sub z}Ti{sub 8-z}O{sub 16} (C = Al{sup 3+}, Cr{sup 3+}, Ga{sup 3+}, Fe{sup 3+}, Mg{sup 2+}, Sc{sup 3+}), synthesized by oxide route, were characterized in terms of structure, microstructure and physical and chemical properties. Iron ions seems to be the most suitable of the studied C cations to get high-performance hollandites. The stability of these ceramics under external electron irradiation, simulating the {beta} particles emitted by radioactive cesium, were also estimated, at the macroscopic and atomic scale. The point defects creation and their thermal stability were followed by electron paramagnetic resonance. (author)

  7. Les verres phosphates : de la spécificité de l'atome de phosphore à la formation, la structure et la durabilité chimique de phosphates vitreux


    Videau, Jean-Jacques; Le Flem, Gilles


    1/ INTERETS DES VERRES PHOSPHATES 2/ QU'EST CE QU'UN VERRE ? 3/ VITRIFICATION DES PHOSPHATES ET STRUCTURES 4/DURABILITE CHIMIQUE ET PHOSPHATES VITREUX 5/ CONCLUSIONS Bibliographie ; Annexes; 3ème cycle; Le verre est l'un des plus vieux matériaux, utilisé et manufacturé par l'homme. Naturel, sous la forme d'obsidienne dans les temps anciens et synthétisé depuis cinq mille ans, il est issu, principalement, de la fusion de silicates. La part réservée aux autres familles de verre dit « verres spé...

  8. Preparation and characterization of (Ba,Cs)(M,Ti) 8O 16 (M = Al 3+, Fe 3+, Ga 3+, Cr 3+, Sc 3+, Mg 2+) hollandite ceramics developed for radioactive cesium immobilization (United States)

    Aubin-Chevaldonnet, V.; Caurant, D.; Dannoux, A.; Gourier, D.; Charpentier, T.; Mazerolles, L.; Advocat, T.


    Among the different matrices proposed for selective and durable immobilization of radioactive cesium, (Ba x,Cs y)(M,Ti) 8O 16 hollandite ceramics, with x + y risks of Cs vaporization during synthesis, calcined powders were sintered in air at moderate temperature (1200 °C). This oxide route appeared as an alternative to the alkoxide route generally proposed to prepare hollandite waste form. For y = 0, single phase Ba x(M,Ti) 8O 16 was obtained only for M 3+ = Al 3+, Cr 3+ and Fe 3+. For y ≠ 0 and Fe 3+, all cesium was incorporated in hollandite and ceramic was well densified. For Cr 3+ and Ga 3+, only 46% and 63%, respectively, of Cs were retained in hollandite phase. For these samples, a high fraction of Cs was either evaporated and/or concentrated in a Cs-rich parasitic phase. Mixed hollandite samples with M 3+ = Ga 3+ + Al 3+ and M 3+ = Fe 3+ + Al 3+ were also synthesized and the best results regarding Cs immobilization and ceramic density were obtained with iron + aluminum but the sample porosity was higher than that of the sample containing only iron. All results were discussed by considering cations size and refractory character of oxides and hollandite ceramics.

  9. Optimisation du poids de fabrication d'une bouteille de verre creux ...

    African Journals Online (AJOL)

    Dans l'industrie du verre d'emballage, la partie la plus importante des pertes financières, est la résultante des écarts des caractéristiques qualité du produit fabriqué par rapport aux spécifications exigées dans le cahier des charges. Nous avons choisi d'illustrer ce problème à travers un produit de référence portant le nom ...

  10. Etude du vieillissement des verres : corrélation entre émissivité apparente (IR) et transmittance (visible)


    Guiheneuf, Vincent; Delaleux, Fabien; Riou, Olivier; Logerais, Pierre-Olivier; Durastanti, Jean-Félix


    International audience; Le verre joue un rôle majeur comme protection supérieure, substrat et piégeage de la lumière dans la plupart des systèmes PV. Cependant, des travaux ont montré qu'au cours de sa durée de vie, un panneau solaire photovoltaïque perd entre 10 et 15% de son rendement, essentiellement à cause de pertes optiques. Nous avons testé une méthode de contrôle non destructif et non intrusif permettant de diagnostiquer l'état de vieillissement du verre sodocalcique, à l'aide d'une c...

  11. Heavy ion irradiations on synthetic hollandite-type materials: Ba{sub 1.0}Cs{sub 0.3}A{sub 2.3}Ti{sub 5.7}O{sub 16} (A=Cr, Fe, Al)

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Ming, E-mail: [Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Tumurugoti, Priyatham; Clark, Braeden; Sundaram, S.K. [Kazuo Inamori School of Engineering, The New York State College of Ceramics, Alfred University, Alfred, NY 14802 (United States); Amoroso, Jake; Marra, James [Materials Science & Technology Directorate, Savannah River National Laboratory, Aiken, SC 29808 (United States); Sun, Cheng [Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lu, Ping [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Wang, Yongqiang [Materials Science & Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Jiang, Ying-Bing [TEM Laboratory, University of New Mexico, Albuquerque, NM 87131 (United States)


    The hollandite supergroup of minerals has received considerable attention as a nuclear waste form for immobilization of Cs. The radiation stability of synthetic hollandite-type compounds described generally as Ba{sub 1.0}Cs{sub 0.3}A{sub 2.3}Ti{sub 5.7}O{sub 16} (A=Cr, Fe, Al) were evaluated by heavy ion (Kr) irradiations on polycrystalline single phase materials and multiphase materials incorporating the hollandite phases. Ion irradiation damage effects on these samples were examined using grazing incidence X-ray diffraction (GIXRD) and transmission electron microscopy (TEM). Single phase compounds possess tetragonal structure with space group I4/m. GIXRD and TEM observations revealed that 600 keV Kr irradiation-induced amorphization on single phase hollandites compounds occurred at a fluence between 2.5×10{sup 14} Kr/cm{sup 2} and 5×10{sup 14} Kr/cm{sup 2}. The critical amorphization fluence of single phase hollandite compounds obtained by in situ 1 MeV Kr ion irradiation was around 3.25×10{sup 14} Kr/cm{sup 2}. The hollandite phase exhibited similar amorphization susceptibility under Kr ion irradiation when incorporated into a multiphase system. - Graphical abstract: 600 keV Kr irradiation-induced amorphization on single phase hollandites compounds occurred at a fluence between 2.5×10{sup 14} Kr/cm{sup 2} and 5×10{sup 14} Kr/cm{sup 2}. The hollandite phase exhibited similar amorphization susceptibility under Kr ion irradiation when incorporated into a multiphase system. This is also the first time that the critical amorphization fluence of single phase hollandite compounds were determined at a fluence of around 3.25×10{sup 14} Kr/cm{sup 2} by in situ 1 MeV Kr ion irradiation. Display Omitted.

  12. Sobre la traducción de «Die Verrücktheit (Paranoia)», de Emil Kraepelin


    Vicente F. Donnoli; María Gabriela Ortiz; Mariela Pampaluna


    La obra «Die Verrücktheit (Paranoia)», de Emil Kraepelin, escrita en el siglo XIX con varias reediciones hasta principios del siglo XX, se tradujo al español en Argentina en 2006. En este artículo se aborda la importancia de la obra desde el punto de vista de la psicología clínica y la terminología psiquiátrica, se analizan las principales dificultades de su traducción al español y se presenta un glosario alemán-español de términos relacionados. -----------------------------------------------...

  13. Le moulage pour la reconstitution des lacunes en restauration de la céramique et du verre

    Directory of Open Access Journals (Sweden)

    Hélène Blanpain


    Full Text Available La technique de reconstitution des lacunes par moulage est très vaste. Elle présente une large gamme de produits et de procédés susceptibles d’être employés dans le domaine de la restauration de la céramique et du verre. Leur choix et leur bonne mise en œuvre dépendront de plusieurs facteurs comme la nature de l’élément à mouler, sa forme et la nature du matériau de comblement choisi.The technique of gap-filling by molding is very vast. It presents a wide range of products and processes than can be used in the field of the restoration of ceramic and glass objects. Their choice depends on several factors : the material of the object, its shape, and the choice of the filling product.

  14. Vieillissement des matériaux composites verre-polyester eb mileiu marin : délaminage d'origine osmotique


    Castaing, Philippe


    Les matériaux composites à matrice polymère et renfort minéral, revêtus de gelcoat (résine pigmentée de protection), sont largement utilisés en construction nautique, ou pour diverses applications courantes comme les canalisations, réservoirs, piscines et carrosseries. Cependant ces matériaux composites verre/polyester résistent de façon inégale au vieillissement climatique (humidité de l'air, rayonnement ultraviolet et immersion en eau de mer). En particulier, un endommagement d'origine osmo...

  15. Synthesis and stability under electron irradiation of a hollandite structure-type Ba{sub 1.16}Al{sub 2.32}Ti{sub 5.68}O{sub 16} ceramic envisaged for radioactive cesium immobilization; Synthese et stabilite sous irradiation electronique d'une ceramique Ba{sub 1,16}Al{sub 2,32}Ti{sub 5,68}O{sub 16} de structure hollandite envisagee pour le confinement de cesium radioactif

    Energy Technology Data Exchange (ETDEWEB)

    Aubin-Chevaldonnet, V.; Caurant, D.; Gourier, D. [Ecole Nationale Superieure de Chimie de Paris (ENSCPParisTech), Lab. de Chimie de la Matiere Condensee de Paris, 75 - Paris (France); Charpentier, Th. [CEA Saclay, Lab. de Structure et Dynamique par Resonance Magnetique, DSM/DRECAM/SCM - CEA CNRS (URA 331), 91 - Gif-sur-Yvette (France); Esnouf, St. [Ecole Polytechnique, Lab. des Solides Irradies, 91 - Palaiseau (France)


    Hollandite structure-type Ba{sub x}Cs{sub y}(M,Ti){sub 8}O{sub 16} (x + y {<=} 2, M trivalent cation) ceramics are currently envisaged as a specific waste form for radioactive cesium immobilization. In order to simulate the effect of cesium {beta} decay on this kind of matrix, the structural modifications and the paramagnetic point defects induced by external electron irradiations near room temperature in a simplified Ba{sub 1.16}Al{sub 2.32}Ti{sub 5.68}O{sub 16} hollandite composition were studied mainly by EPR and NMR. Modifications of Al{sup 3+} and Ti{sup 4+} ions' environment were observed and are due to both the formation of oxygen vacancies and to barium ions displacement. Electron (Ti{sup 3+}) and hole (O{sub 2}{sup -}) centres were observed. The stability of these centres was good at room temperature but thermal treatments performed between 50 and 850 C generated new paramagnetic defects originating from previous defects. These new defects correspond to titanyl-type Ti{sup 3+} ions located on grain surface and to oxygen aggregates in their bulk. (authors)

  16. Spectres infrarouges de verres à haute temperature par inversion de l'émission thermique de couches anisothermes (United States)

    Sakami, M.; Lallemand, M.


    The infrared absorption spectra of silicate glasses and boric anhydrid at high temperature are worked out by means of an inverse technique of optimization from the emission spectra. The sample's emission spectral intensities are measured by a Fourier Transform lnfra-Red spectrometer. Specimens are plane parallel slabs which are deposited on a crusible. Their lower face is in contact of the crusible and isothermal but the upper one exchanges heat with the atmosphere by natural convection. In such conditions the glass slabs are submitted to high thermal gradients and the optimization method used is a non-linear constainted iterative method. The resulting spectra are compared to absorption spectra obtained by transmission spectrometry. Les spectres d'absorption infrarouge de verres de silicate et d'anhydride borique portés à haute température sont obtenus par inversion des spectres d'émission au moyen d'une méthode d'optimisation. Les luminances spectrales émises par les échantillons sont mesurées à l'aide d'un spectromètre à transformée de Fourier. Les échantillons sont des lames planes parallèles déposées dans un creuset ; leur surface inférieure est maintenue vers 1 000 K, alors que leur surface supérieure échange sa chaleur à l'air libre par convection naturelle. Dans ces conditions les lames sont soumises à de forts gradients thermiques. En présence de ces gradients une méthode itérative d'optimisation non linéaire contrainte est mise en œuvre. On compare les résultats obtenus aux spectres d'absorption mesurés directement par spectrométrie de transmission.

  17. Archéologie du vitrail et du décor de verre en France (Ve-XIIe siècle

    Directory of Open Access Journals (Sweden)

    Christian Sapin


    Full Text Available Par l’organisation d’une table ronde de travail, il s’agit de réunir et de confronter les données récentes en France issues de découvertes de premiers vitraux et décors de verre provenant de fouilles archéologiques ou de fonds de musées. Seront mis en évidence, entre autres, les arguments chronologiques, les données d’analyses et la présence de premiers décors. Une publication de ces travaux est envisagée.15 juinIntroductions et synthèses Texte et archéologie. Point sur les origines, Francesc...

  18. Studies of (Cs,Ba)-hollandite dissolution under gamma irradiation at 95 °C and at pH 2.5, 4.4 and 8.6 (United States)

    Suzuki-Muresan, T.; Vandenborre, J.; Abdelouas, A.; Grambow, B.; Utsunomiya, S.


    In the frame of the former French 1991-law on waste management, which was extended in 2006-law, hollandite ceramic was studied as a potential specific conditioning matrix for caesium isotopes (long-life radionuclide 135Cs and the strong heat generating radionuclide 137Cs). In this general study of Cs-containment in a ceramic matrix, the chemical durability was pointed out as a key property. Leaching experiments in static mode were conducted during 240 days at various pH-values from acidic to alkaline range. The initial leaching rates between 0 and 45 days are faster for Cs than for Ba and the average for the caesium are (1.4 ± 0.1) × 10 -4 g/m 2/d (pH 2.5), (6.4 ± 0.9) × 10 -5 g/m 2/d (pH 4.4) and (3.1 ± 0.6) × 10 -5 g/m 2/d (pH 8.6), and for the barium (6 ± 1) × 10 -5 g/m 2/d (pH 2.5), (2.8 ± 0.3) × 10 -5 g/m 2/d (pH 4.4), and (2 ± 2) × 10 -6 g/m 2/d (pH 8.6). At the equilibrium between 45 and 240 days, the normalised mass losses average for caesium are (8.2 ± 0.3) × 10 -3 g/m 2 (pH 2.5), (5.2 ± 0.4) × 10 -3 g/m 2 (pH 4.4) and (4.1 ± 0.2) × 10 -3 g/m 2 (pH 8.6), and for barium (3.7 ± 0.4) × 10 -3 g/m 2 (pH 2.5), (2.0 ± 0.1) × 10 -3 g/m 2 (pH 4.4) and (4 ± 2) × 10 -4 g/m 2 (pH 8.6). Caesium and barium are incongruently released in solution with a correlation slope close to 0.5 at pH 2.5 and pH 4.4 and very low (near 0.02) in alkaline solution. Sorption experiments with radioactive isotopes ( 137Cs and 133Ba) were conducted on hollandite pre-leached in aqueous solutions. Caesium and barium release is controlled by the surface reactions. Leaching experiments and isotopic addition experiments ( 137Cs- and 133Ba-radiotracer) indicate that caesium behaviour is independent on pH-values, whereas barium behaviour is strongly dependent. Additional experiments in the presence of gamma irradiation ( 60Co source) did not show any significant effect on hollandite leaching process.

  19. Un verre de trop

    Directory of Open Access Journals (Sweden)

    Pascal Brissette


    Full Text Available Au nombre des mythes qui accompagnent la formation de la modernité littéraire, on compte celui de la bohème, qui témoigne, comme Nathalie Heinich l’a bien montré dans L’Élite artiste, des difficultés que les producteurs symboliques éprouvent à conjuguer les critères de la singularité et du travail en communauté. La théâtralité de la « vie de bohème », son excentricité, ses tics et son chic sont au fondement de regroupements d’écrivains qui défendent paradoxalement le caractère vocationnel de ...

  20. Verres pour la Photostructuration


    Maurel, Clément


    The increment of the need of new technologies in photonics is a perfect vector for the research and development of new components for integrated optics. The photostructuration of new glassy materials with novel optical properties is proposed. Two approaches have been conducted : Modification of the glass matrix or addition of photosensitive ions. - Germanium and gallium oxysulfide glasses have been elaborated into bulk glasses as well as amorphous thin films. They exhibit optical properties i...

  1. Etude par analyse enthalpique différentielle d'un verre métallique Fe-Cr-C-P-Si. Influence de la vitesse d'hypertrempe


    Fouquet, F.; Allemand, J.P.; Perez, J.; De Guillebon, B.


    Les rubans de verre métallique ont été obtenus par hypertrempe du liquide avec différentes vitesses du substrat rotatif donc différentes vitesses d'hypertrempe. L'influence de cette vitesse sur l'état structural des rubans bruts d'élaboration mais également sur la relaxation structurale ultérieure a été précisée en utilisant l'analyse enthalpique différentielle ; outre les informations concernant les effets thermiques associés à la relaxation ou à la cristallisation des différents rubans, cet...

  2. L’utilisation d’adhésifs optiques réticulables aux UV pour le collage d’objets d’art en verre transparent coloré, à surface d’encollage réduite

    Directory of Open Access Journals (Sweden)

    Viviane Bechoux


    Full Text Available La recherche porte sur une double problématique :1° La possibilité d’utiliser les adhésifs réticulables aux UV  pour coller le verre transparent coloré. 2° Le collage du verre  s’avère très complexe quand les éléments à assembler sont fins, fragiles et quand la surface d’encollage est réduite à quelques millimètres.Dans ce cas précis, la solidité mécanique du collage et la rapidité de polymérisation de l’adhésif sont les premiers critères à prendre en compte pour assurer un assemblage final fiable.This research focuses on two issues : 1° The possibility to use UV-crosslinkable adhesives to bond transparent coloured glass.2° The glass bonding is very complex when the parts to be joined are thin, fragile, and when the bonding surface is reduced to a few millimetres in size. In this case, the mechanical strength of the bonding and the speed of the curing process of the adhesive are the first criteria to be taken into account to ensure a reliable final bonding.

  3. Le verre à vitre et l’archéologie de la fin de l’Antiquité au XIIe siècle. Premières approches et perspectives

    Directory of Open Access Journals (Sweden)

    Christian Sapin


    Full Text Available Le vitrail a longtemps été considéré comme représentatif du plein Moyen Âge (XIe-XIIe siècle au plus tôt. Si quelques textes historiques impliquaient l’existence de vitrail à l’époque mérovingienne, la rareté des verres plats archéologiques, datés, ne permettait pas d’écrire avec précision une histoire du vitrail.Cette histoire est depuis quelques années revisitée par les sources archéologiques, aussi ténues puissent-elles paraître. La révolution la plus importante est, dans les années 1960,...

  4. Génération d'onde stokes du second ordre et effet laser dans une fibre optique a cœur suspendu en verre de chalcogénure AsSe


    Hey Tow, Kenny; Besnard, Pascal; Brilland, Laurent; Toupin, Périne; Troles, Johann; Méchin, David; Trégoat, Denis


    National audience; Une étude expérimentale sur les propriétés de la rétrodiffusion Brillouin stimulée dans une fibre optique à cœur suspendu en verre de chalcogénure AsSe est présentée. Avec seulement un mètre de fibre, nous générons suffisamment de gain Brillouin pour obtenir un laser à fibre monomode de type Fabry-Perot. Nous démontrons aussi la génération du second ordre Brillouin dans ces fibres avec 0,5 W de pompe.



    Guyot, F; Fouquet, F.; Perez, J.


    Les variations de l'effet ƊE et de l'amortissement magnétomécanique associées à l'évolution structurale d'un verre métallique ferromagnétique Fe-B-Si-C ont été étudiées. L'effet ƊE négligeable dans l'état brut d'hypertrempe devient très important après relaxation structurale de l'alliage puis disparait dès l'amorce de la cristallisation.

  6. Alteration of R7T7-type nuclear glass in deep geological storage conditions; Alteration du verre de confinement de dechets type R7T7 en condition de stockage geologique

    Energy Technology Data Exchange (ETDEWEB)

    Combarieu, G. de


    This PhD thesis is aimed to study the alteration of SON68 glass, French inactive glass of R7T7-type, in contact with near field materials of a deep geological storage (French concept from ANDRA) which are mainly metallic iron and Callovo-Oxfordian clay. Therefore, experiments involving a 'glass-iron-clay' system at lab-scale have been carried out. Interactions between glass, iron and clay have been characterised from submicron to millimeter scale by means of SEM, TEM, XRD and XAS and Raman spectroscopies in terms of chemistry and crystal-chemistry. In the mean time, a conceptual model of glass alteration has been developed to account for most of the experimental observations and known mechanisms of alteration. The model has been then transposed within the transport-chemistry code HYTEC, together with developed models of clay and iron corrosion, to simulate the experiments described above. This work is thus a contribution to the understanding of iron corrosion in Callovo-Oxfordian clay and subsequent glass alteration in the newly formed corrosion products, the whole process being considered as a lab-scale model of a deep geological storage of radioactive wastes. (author)

  7. Contribution to the study of stimulated emission in neodymium-doped glass; Contribution a l'etude de l'emission stimulee dans le verre dope au neodyme

    Energy Technology Data Exchange (ETDEWEB)

    Jego, J.M. [Commissariat a l' Energie Atomique, Limeil-Brevannes (France). Centre d' Etudes; Faculte des Sciences de Rennes, 35 (France)


    faut attendre cependant quelques quarante annees pour voir les premieres realisations. Le maser fonctionnant dans le domaine des ondes micrometriques apparait en 1954. Dans le domaine optique, le premier 'LASER' est realise par MAIMAN en 1960. L'atome actif etait le chrome au sein d'une matrice d'alumine (rubis). le monocristal fluorescent etait place entre deux reflecteurs charges de maintenir dans le mileu une inversion provoquee de population jusqu'a atteindre les conditions d'emission. L'effet laser a permis de realiser beaucoup de generateurs de raies (plusieurs centaines) couvrant la gamme optique avec les mileux tant gazeux que liquides ou solides. Parmi ceux ci, le neodyme presente une transition entre les niveaux 4 F{sub 3/2} et 4 I{sub 11/2} qui a permis la realisation de lasers de tres grande puissance. Ce travail etudie les conditions de formation d'une impulsion declenchee et de son amplification dans le verre dope au neodyme. Des mesures precises des divers rendements interessants dans ces processus nous ont permis de connaitre la valeur de l'inversion de population realisee dans le milieu et d'etudier le detail de l'emission stimulee. (auteur)

  8. Verre doelen, onmiddellijke frustraties: zelfregulatieprocessen in gezondheidsgedrag

    NARCIS (Netherlands)

    Ridder, D.T.D. de


    Wat mensen doen en laten in het perspectief van wat ze belangrijk vinden is een thema dat in psychologische termen wordt aangeduid met zelfregulatie – een begrip dat het hele scala aan gedragingen omvat dat te maken heeft met de manier waarop mensen doelen formuleren, de strategieën die ze toepassen

  9. Paranoia (Verrücktheit - 1904

    Directory of Open Access Journals (Sweden)

    Emil Kraepelin


    Full Text Available Aqui publicamos a tradução brasileira (1905 do capítulo sobre a paranoia, extraído da sétima edição alemã (1904 do tratado (Lehrbuch de psiquiatria de Emil Kraepelin. O autor discute o diagnóstico da paranoia e, particularmente, faz a distinção entre a paranoia e a demência precoce.

  10. Paranoia (Verrücktheit) - 1904


    Emil Kraepelin


    Aqui publicamos a tradução brasileira (1905) do capítulo sobre a paranoia, extraído da sétima edição alemã (1904) do tratado (Lehrbuch) de psiquiatria de Emil Kraepelin. O autor discute o diagnóstico da paranoia e, particularmente, faz a distinção entre a paranoia e a demência precoce. This is the Brazilian translation (1905) of the chapter on paranoia, in seventh German edition (1904) of Emil Kraepelin's Textbook (Lehrbuch). In it he discusses the diagnosis of paranoia and, especially, ma...

  11. Acquisition of rheological and calorimetric properties of borosilicate glass to determine the free energy of formation; Determination des energies libres de formation des verres borosilicates par des mesures calorimetriques et viscosimetriques

    Energy Technology Data Exchange (ETDEWEB)

    Linard, Y. [CEA Valrho, (DCC/DRRV/SCD), 30 - Marcoule (France)]|[Institut de Physique du Globe de Paris, Dept. des Geomateriaux, 75 - Paris (France); Advocat, Th. [CEA Valrho, (DCC/DRRV/SSCD), 30 - Marcoule (France)


    No fundamental thermodynamic data, such as the entropy {delta}{sub f}S T) and enthalpy {delta}{sub f}H T) of formation are currently available for nuclear borosilicate glasses. They are necessary to assess the glass thermodynamic stability in water, one of the most important potential long-term glass alteration vectors. Three glass composition ranges were investigated: - 8 compositions ranging from a ternary B{sub 2}O{sub 3}-SiO{sub 2}--Na{sub 2}O (BSN) glass to the simulated SON 68 industrial glass for containment of high active nuclear wastes after reprocessing spent uranium oxide fuel from light water reactors. The basic BSN glass was gradually modified with the additives: Al{sub 2}O{sub 3}, CaO, ZrO{sub 2}, Ce{sub 2}O{sub 3}, Li{sub 2}O and Fe{sub 2}O{sub 3}, and non-radioactive surrogate fission product oxides. - A second using another BSN ternary glass to which Al{sub 2}O{sub 3}, MgO and a group of non-radioactive surrogate fission product oxides, representative of natural uranium GCR fuel, were added. - A third range consisting of various BSN ternary glass compositions. All the glass specimens were fabricated by melting the oxides, carbonates anal nitrates at 1273 to 1473 K in a platinum crucible. Experimental methods based on calorimetry and viscosimetry techniques were used to determine the heat capacity Cp of each glass composition, a necessary parameter in addition to the known heat capacities of the basic glass component oxides, for calculating {delta}{sub f}S T) and {delta}{sub f}S T). The heat capacity Cp was measured between 273 K and 1480 K through a combination of three experimental devices: a low-temperature adiabatic calorimeter, a differential scanning calorimeter, and an ice calorimeter. The glass configuration entropy S{sup conf}(T{sub g}) necessary to obtain the glass entropy of formation (Eqn.(3)) was determined from tile glass rheological properties. A low-temperature viscosimeter was used to measure the strain {epsilon} of a glass specimen

  12. High-sensitivity gamma spectroscopy for extended sources. Application to activity measurements on the human body, on glass, and on soil; Spectrographie gamma a grande sensibilite pour sources etendues. Application a la mesure de l'activite du corps humain, du verre et du sol

    Energy Technology Data Exchange (ETDEWEB)

    Jouve, B


    (dosage du potassium dans les verres). (auteur)

  13. Pore-Scale Flow Simulations: Model Predictions Compared with Experiments on Bi-Dispersed Granular Assemblies Simulation d’écoulements à l’échelle porale : comparaison des prédictions du modèle et d’expériences sur mélanges de billes de verre bi-disperses

    Directory of Open Access Journals (Sweden)

    Tong A.-T.


    Full Text Available A method is presented for the simulation of pore flow in granular materials. The numerical model uses a combination of the discrete element method for the solid phase and a novel finite volume formulation for the fluid phase. The solid is modeled as an assembly of spherical particles, where contact interactions are governed by elasto-plastic relations. Incompressible Stokes flow is considered, assuming that inertial forces are small in comparison with viscous forces. Pore geometry and pore connections are defined locally through regular triangulation of spheres, from which a tetrahedral mesh arises. The definition of pore-scale hydraulic conductivities is a key aspect of this model. In this sense, the model is similar to a pore-network model. Permeability measurements on bi-dispersed glass beads are reported and compared with model predictions, validating the definition of local conductivities. Une méthode est présentée pour la simulation de l’écoulement porale dans les matériaux granulaires. Le modèle numérique est basé sur la méthode des éléments discrets pour la phase solide et sur une nouvelle méthode de type volumes finis pour la phase fluide. Le solide est modélisé comme un arrangement de particules sphériques avec des interactions de type élasto-plastique aux contacts. On considère un écoulement de Stokes incompressible en supposant que les forces inertielles sont négligeables par rapport aux forces visqueuses. La géométrie des pores et leur connectivité sont définies sur la base d’une triangulation régulière des sphères qui aboutit à un maillage tétraédrique. La définition des conductivités hydrauliques à l’échelle des pores est un point clef du modèle qui se rapproche sur ce point à des modèles de type pore-network. Des mesures de perméabilités sur des assemblages bi-disperses de billes de verre sont présentées et comparées aux prédictions du modèle ce qui valide la définition des

  14. Glass packages in interim storage; Les verres dans les stockages

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet-Francillon, N.


    This report summarize the current state of knowledge concerning the behavior of type C waste packages consisting of vitrified high-level solutions produced by reprocessing spent fuel. The composition and the physical and chemical properties of the feed solutions are reviewed, and the vitrification process is described. Sodium alumino-borosilicate glass compositions are generally employed - the glass used at la Hague for LWR fuel solutions, for example, contains 45 % SiO{sub 2}. The major physical, chemical, mechanical and thermal properties of the glass are reviewed. In order to allow their thermal power to diminish, the 3630 glass packages produced (as of January 1993) in the vitrification facilities at Marcoule and La Hague are placed in interim storage for several decades. The actual interim storage period has not been defined, as it is closely related to the concept and organization selected for the final destination of the packages: a geological repository. The glass behavior under irradiation is described. Considerable basic and applied research has been conducted to assess the aqueous leaching behavior of nuclear containment glass. The effects of various repository parameters (temperature, flow rate, nature of the environmental materials) have been investigated. The experimental findings have been used to specify a model describing the kinetics of aqueous corrosion of the glass. More generally all the ``source term`` models developed in France by the CEA or by ANDRA are summarized. (author). 152 refs., 33 figs.

  15. Etude rheologique des composites charges de fibres de verre courtes (United States)

    Sepehr, Maryam

    The rheological behavior of short-fiber polypropylene has been studied in shear flow. Because of some restrictions in the measurement and the complex behavior of the matrix, we chose to use model fiber suspensions in two different types of matrix, a Newtonian polybutene and a Boger fluid. The steady-state viscosity of the Newtonian polybutene increased by adding fibers and the behavior of the fiber suspensions essentially remained Newtonian. The Boger fluid was obtained by adding a high molecular weight polyisobutylene to the Newtonian polybutene. The transient behavior of all types of fiber suspensions (with the viscoelastic, the Newtonian and the Boger fluid matrices) in shear flow has been investigated. Following a first deformation, the sample has been sheared in the reverse direction and a viscosity overshoot called the "reverse overshoot" was measured at a larger strain in comparison with the primary viscosity overshoot. The reverse overshoot has been attributed to tumbling of fibers that are not totally aligned with the flow direction even after a very long time. When the flow was reversed, the normal stress difference took initially minimum values and depicted a smaller positive overshoot before reaching the steady-state plateau. Two models have been used to simulate the rheological behavior of fiber suspensions. The first model is based on the Folgar and Tucker equation for fiber motion and Lipscomb constitutive equation. This model describes qualitatively well the transient behavior of fiber suspensions in both forward and reverse direction flows. However, the fiber motions predicted by the model are faster than deducted from the experiments. This was tentatively explained by non-affined deformation and direct contacts with neighboring fibers, reducing fiber rotation. The second model investigated was the extended Jeffery model developed by Grmela et al. (2003) who generalized the Jeffery model, to include fiber-fiber interactions via angular momentum and effective inertia of fibers. With a correct choice for the free energy, the model can describe, in principle, the rheological behavior of fiber suspensions. (Abstract shortened by UMI.)

  16. Nitruration de verres conducteurs ioniques en couches minces


    Hamon, Yohann


    Thin films of nitrided ionic conducting glasses have been deposited by reactive rf magnetron sputtering. Glasses are particularly adapted for an use as electrolyte in electrochemical microsystems. In the case of phosphate glasses, it has already been shown that nitrogen incorporation in the vitreous network increases considerably the ionic conductivity of the deposited thin films. First of all, a measurement apparatus allowing the characterization of thin films conduction properties has been ...

  17. Modeling of glass fusion furnaces; Modelisation des fours de fusion de verre

    Energy Technology Data Exchange (ETDEWEB)

    Mechitoua, N. [Electricite de France (EDF), 78 - Chatou (France). Direction des Etudes et Recherches; Plard, C. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches


    The furnaces used for glass melting are industrial installations inside which complex and coupled physical and chemical phenomena occur. Thermal engineering plays a major role and numerical simulation is a precious tool for the analysis of the different coupling, of their interaction and of the influence of the different parameters. In order to optimize the functioning of glass furnaces and to improve the quality of the glass produced, Electricite de France (EdF) has developed a specialized version of the ESTET fluid mechanics code, called `Joule`. This paper describes the functioning principle of glass furnaces, the interactions between heat transfers and flows inside the melted glass, the interactions between heat transfers and the thermal regulation of the furnace, the interactions between heat transfers and glass quality and the heat transfer interactions between the melted glass, the furnace walls and the combustion area. (J.S.)

  18. Heterogeneities in nuclear waste glass; Heterogeneites dans le verre de confinement industriel

    Energy Technology Data Exchange (ETDEWEB)

    Ladirat, Ch. [CEA Valrho, Dir. de l' Energie Nucleaire, DEN, 30 - Marcoule (France)


    The industrial vitrification of high level radioactive wastes is a 2 stage process. During the first stage, the concentrated solution is heated in a spinning resistance oven at the temperature of 400 Celsius degrees till evaporation and calcination. The second stage begins when the dry residue falls into a melting pot that is maintained at a temperature of 1100-1150 Celsius degrees. Glass fretting is added and the glass is elaborated through the fusion of the different elements present in the melting pot. Heterogeneities in the glass may be associated to: - the presence in the solution to vitrify of insoluble elements from the dissolution of the fuel (RuO{sub 2}, Rh, Pd), - the presence of minuscule metal scraps (Zr) that have been produced during the cutting of the fuel element, - the failures to conform to the technical specifications of the vitrification process, for instance, temperatures or flow rates when introducing the different elements in the melting pot. (A.C.)

  19. Lage landen, verre horizonten. De verbinding van natuur, landschap en 'Nederlandse' identiteit in internationaal perspectief

    Directory of Open Access Journals (Sweden)

    K. Davids


    Full Text Available Karel Davids, Low countries, faraway horizons. The relation between nature, landscape and ‘Dutch’ identity in a comparative perspectiveHow did nature, landscape and identity in the Netherlands become intertwined during the course of the nineteenth and twentieth centuries? And more particularly, how was this development linked up with changes in the relationship between the Netherlands and other parts of the globe? These are the key questions addressed in this essay. The article argues that the growing interconnection between nature, landscape and identity can only partly be explained by home-grown traditions, such as the increased cooperation between science and capital or the presence of a highly developed art of landscape painting. In many respects, developments in the Netherlands showed in fact striking parallels and connections with developments in other areas of the world. Numerous elements in the newly-emerged view of nature and landscape were adopted from abroad and Dutchmen ardently projected their own national ambitions and pretensions in confrontations with wild nature and foreign rivals outside their territory along the North Sea. Thus, the `Dutch’ identity was also constructed in the jungle of the East-Indies and the thin air of the Alps.

  20. Metal–insulator transition tuned by magnetic field in Bi 1.7 V 8 O 16 hollandite

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Amber M.; Wilfong, Brandon; Moetakef, Pouya; Brown, Craig M.; Zavalij, Peter; Rodriguez, Efrain E.


    A metal–insulator transition tuned by application of an external magnetic field occurs in the quasi-one dimensional system Bi1.7V8O16, which contains a mix of S = 1 and S = 1/2 vanadium cations. Unlike all other known vanadates, the magnetic susceptibility of Bi1.7V8O16 diverges in its insulating state, although no long-range magnetic ordering is observed from neutron diffraction measurements, possibly due to the frustrated geometry of the triangular ladders. Magnetotransport measurements reveal that the transition temperature is suppressed upon application of an external magnetic field, from 62.5 K at zero field to 40 K at 8 T. This behavior is both hysteretic and anisotropic, suggesting t2g orbital ordering of the V3+ and V4+ cations drives a first-order structural transition. Single crystal X-ray diffraction reveals a charge density wave of Bi3+ cations with a propagation vector of 0.846c*, which runs parallel to the triangular chain direction. Neutron powder diffraction measurements show a first-order structural transition, characterized by the coexistence of two tetragonal phases near the metal–insulator transition. Finally, we discuss the likelihood that ferromagnetic V–V dimers coexist with a majority spin-singlet state below the transition in Bi1.7V8O16.

  1. Determination of the free enthalpies of formation of borosilicate glasses; Determination des enthalpies libres de formation des verres borosilicates. Application a l'etude de l'alteration des verres de confinement de dechets radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Linard, Y


    This work contributes to the study of the thermochemical properties of nuclear waste glasses. Results are used to discuss mechanisms and parameters integrated in alteration models of conditioning materials. Glass is a disordered material defined thermodynamically as a non-equilibrium state. Taking into account one order parameter to characterise its configurational state, the metastable equilibrium for the glass was considered and the main thermochemical properties were determined. Calorimetric techniques were used to measure heat capacities and formation enthalpies of borosilicate glasses (from 3 to 8 constitutive oxides). Formation Entropies were measured too, using the entropy theory of relaxation processes proposed by Adam and Gibbs (1965). The configurational entropy contribution were determined from viscosity measurements. This set of data has allowed the calculation of Gibb's free energies of dissolution of glasses in pure water. By comparison with leaching experiments, it has been demonstrated that the decreasing of the dissolution rate at high reaction progress cannot be associated to the approach of an equilibrium between the sound glass and the aqueous solution. The composition changes of the reaction area at the glass surface need to be considered too. To achieve a complete description of the thermodynamic stability, the equilibrium between hydrated de-alkalinized glass and/or the gel layer with the aqueous solution should also be evaluated. (author)

  2. 3 and 4 oxidation state element solubilities in borosilicate glasses. Implement to actinides in nuclear glasses; Solubilite des elements aux degres d'oxydation (3) et (4) dans les verres de borosilicate. Application aux actinides dans les verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Cachia, J.N


    In order to ensure optimal radionuclides containment, the knowledge of the actinide loading limits in nuclear waste glasses and also the comprehension of the solubilization mechanisms of these elements are essential. A first part of this manuscript deals with the study of the differences in solubility of the tri and tetravalent elements (actinides and surrogates) particularly in function of the melting temperature. The results obtained indicate that trivalent elements (La, Gd, Nd, Am, Cm) exhibit a higher solubility than tetravalent elements (Hf, Th, Pu). Consequently, it was planned to reduce plutonium at the oxidation state (III), the later being essentially tetravalent in borosilicate glasses. An innovating reduction process of multi-valent elements (cerium, plutonium) using silicon nitride has been developed in a second part of this work. Reduced plutonium-bearing glasses synthesized by Si{sub 3}N{sub 4} addition made it possible to double the plutonium solubility from 2 to 4 wt% at 1200 deg C. A structural approach to investigate the differences between tri and tetravalent elements was finally undertaken. These investigations were carried out by X-rays Absorption Spectroscopy (EXAFS) and NMR. Trivalent rare earth and actinide elements seem to behave as network modifiers while tetravalent elements rather present true intermediaries' behaviour. (author)

  3. Réponse vibrationnelle basse fréquence des verres de silice : modélisation et spectroscopie RAMAN


    Mantisi, Boris


    This thesis discusses the mechanical and vibrationnal behaviour of silica glasses. Here, classical molecular dynamics methods are used to model a glass using asmoothed and truncated BKS potential. The model is validated through structural and dynamical comparisons with X-rays and neutrons scattering experiments. The numerical sample in mechanically loaded, and the response to a strain (hydrostatic compression, shear at constant volume or pressure in the elastic domain and beyond) is studied i...

  4. Étude analytique et numérique de la transition Superfluide - verre de Bose à deuxdimensions


    Álvarez Zúñiga, Juan Pablo


    The interplay of disorder (i.e. impurities) and interactions is one of the most fundamentalquestions in Condensed Matter Physics that has received a lot attention in the past couple ofdecades. The quantum phase transition from Superfluid to Bose glass driven by disorder haspuzzled theoreticians and experimentalists alike, leaving unresolved questions despite their bestefforts. The work presented in this thesis addresses some of these questions for two models ofdisordered hard-core bosons in t...

  5. Thermodynamical modeling of nuclear glasses: coexistence of amorphous phases; Modelisation thermodynamique des verres nucleaires: coexistence entre phases amorphes

    Energy Technology Data Exchange (ETDEWEB)

    Adjanor, G


    Investigating the stability of borosilicate glasses used in the nuclear industry with respect to phase separation requires to estimate the Gibbs free energies of the various phases appearing in the material. In simulation, using current computational resources, a direct state-sampling of a glassy system with respect to its ensemble statistics is not ergodic and the estimated ensemble averages are not reliable. Our approach consists in generating, at a given cooling rate, a series of quenches, or paths connecting states of the liquid to states of the glass, and then in taking into account the probability to generate the paths leading to the different glassy states in ensembles averages. In this way, we introduce a path ensemble formalism and calculate a Landau free energy associated to a glassy meta-basin. This method was validated by accurately mapping the free energy landscape of a 38-atom glassy cluster. We then applied this approach to the calculation of the Gibbs free energies of binary amorphous Lennard-Jones alloys, and checked the correlation between the observed tendencies to order or to phase separate and the computed Gibbs free energies. We finally computed the driving force to phase separation in a simplified three-oxide nuclear glass modeled by a Born-Mayer-Huggins potential that includes a three-body term, and we compared the estimated quantities to the available experimental data. (author)

  6. Influence of microorganisms on the alteration of glasses; Influence des microorganismes sur l'alteration des verres

    Energy Technology Data Exchange (ETDEWEB)

    Besnainou, B.; Libert, M.F. [CEA Cadarache, 13 - Saint Paul lez Durance (France). Dept. d' Entreposage et de Stockage des Dechets


    Under specific conditions, microorganisms may enhance the alteration process of basaltic glass. However bacterial activity in the near field of a glass container would be possible only in environmental conditions provide nutrients and energetic substrates for bacterial growth. Depending of these conditions, microorganisms can: - modify the pH or the medium, - consume or produce soluble organic acids. To qualify the long term behaviour of glass, in presence of microorganisms, a qualitative and quantitative estimation of microbial activity potentialities and their consequences is needed. This must be achieved in studying the availability of the chemical species in the environment. (authors)

  7. Influence of nuclear glasses composition on their liability to deterioration; Influence de la composition des verres nucleaires sur leur alterabilite

    Energy Technology Data Exchange (ETDEWEB)

    Tovena, I.


    This contributes to the study of the nuclear glasses composition influence on their liability to deterioration. The methodology of the experimental research used has lead to define between the thirty oxides which form the reference glass light water, six oxides of interest. For each of these oxides, a composition variation area has been defined. A matrix of twenty glass compositions has then been defined. The preparation of materials of these compositions has sometimes lead to materials weakly heterogeneous which have been characterized before deterioration. This study has been completed by those of three glasses in a composition variation area narrower of the light water nuclear glass : the R7T7 and two glasses at limits having respectively an initial dissolution velocity at 100 degrees Celsius theoretically maximum and minimum. Some deterioration parameters in pure water have been experimentally measured on the twenty three glasses : 1) an initial dissolution velocity at 100 degrees (Vo{sub 1}00) Celsius and another one at 90 degrees Celsius (Vo{sub 9}0) 2) a dissolution velocity in conditions near the saturation at 90 degrees Celsius 3) an apparent solubility of glass based on the ortho silicic acid activity 4) the evolution of the dissolution kinetics at 90 degrees Celsius in sub-saturated medium towards saturated medium 5) the alteration films nature developed at the glasses surface during these last alteration tests. Some thermodynamic and structural models have been studied in order to predict Vo{sub 9}0 and Vo{sub 1}00. The dissolution kinetic law developed from reference glass dissolution results has been studied with the calculation code LIXIVER. It has not been able to be used for most of the glasses compositions studied. As a consequence, the glasses dissolution control by a surface reaction which are itself controlled by the only dissolved silica is an hypothesis which is not verified for the greater part of the glasses. (O.L.). refs., figs., tabs.

  8. La cultura che verrà. La comunicazione visiva come strumento trasparente, per un libero accesso a risorse e saperi

    Directory of Open Access Journals (Sweden)

    Enrico Parisio


    Full Text Available Oggi gli apparati tecnologico/comunicativi si garantiscono l’autosufficienza: la diffusione dei messaggi utilizza come “nodi” di propagazione noi stessi, gli utenti. Sono gli apparati che ci impiegano, non siamo noi ad utilizzarli. La  funzione progettuale, deve essere inserita in un contesto totalmente capovolto rispetto al passato: come progettisti dobbiamo favorire fondamentalmente il flusso di informazioni, del tutto eterodiretto. Lasciar accadere è la parola d’ordine, senza alcuna intenzionalità “rappresentativa”. Il soggetto autoritario viene sostituito dalla terza persona, dall’impersonalità degli eventi che incedono, dalle molteplicità, dai soggetti collettivi. L’autore oggi di un progetto è un non autore, un non soggetto, un “egli”. Il progetto di comunicazione visiva deve confrontarsi oggi non solo con i nuovi linguaggi della tecnologia, ma soprattutto con quelli ben più complessi che i soggetti reali attivano sperimentando nuove forme di socialità, di aggregazione, di conflitto.

  9. In situ study of glasses decomposition layer; Etude in situ de la couche d`alteration de verres

    Energy Technology Data Exchange (ETDEWEB)

    Zarembowitch-Deruelle, O


    The aim of this work is to understand the involved mechanisms during the decomposition of glasses by water and the consequences on the morphology of the decomposition layer, in particular in the case of a nuclear glass: the R{sub 7} T{sub 7}. The chemical composition of this glass being very complicated, it is difficult to know the influence of the different elements on the decomposition kinetics and on the resulting morphology because several atoms have a same behaviour. Glasses with simplified composition (only 5 elements) have then been synthesized. The morphological and structural characteristics of these glasses have been given. They have then been decomposed by water. The leaching curves do not reflect the decomposition kinetics but the solubility of the different elements at every moment. The three steps of the leaching are: 1) de-alkalinization 2) lattice rearrangement 3) heavy elements solubilization. Two decomposition layer types have also been revealed according to the glass heavy elements rate. (O.M.) 59 refs.

  10. Die Stigmatisierung der banlieues in Frankreich seit den 1980er Jahren als Verräumlichung und Ethnisierung gesellschaftlicher Krisen


    Glasze, Georg; Weber, Florian


    27. Oktober 2005 in Clichy-sous-Bois, einer Vorstadt von Paris: Zwei Jugendliche sterben auf der Flucht vor der Polizei in einem Umspannwerk. Im Nachgang entwickeln sich Unruhen zwischen Jugendlichen und der Polizei, die ein nationales Ausmaß erreichen und mehr als drei Wochen andauern. Die Ursachen und Hintergründe dieser Vorortunruhen werden in der öffentlichen Diskussion unterschiedlich gerahmt: als Konsequenz städtebaulicher und sozioökonomischer Problemlagen bestimmter Orte, als Ausdruck...

  11. Photostructuration par laser infrarouge femtoseconde de verres photosensibles de phosphates de zinc, d'argent et de gallium


    Bourhis, Kevin


    The development of new vitreous materials in the 40P2O5-55ZnO-xAg2O-(5-x)Ga2O3 diagram permits to take advantage of the Ag+ ion photosensitivity for structuring optical properties within the material. Increasing the gallium oxide content leads to the depolymerisation of the phosphate chains and the reticulation of the glass network by GaOx polyhedra (4 ≤ x ≤ 6). The formation of the latters does not affect the luminescence properties which are related to silver ions in various crystallographi...

  12. Localized Impact Damage in Ceramics. (United States)


    Milieux Vitreux. Applications aux mesures de Quelques Proprieter Physiques des Verres " from Communications Scientifiques et Techniques. 1. Sujet...Scientifiques et Recherches de Base. Congres International du Verre Versailles 27 Septembre-2 Octobre 1971, Edite par P. Institut de Verre Paris (1971), p

  13. Etude des conditions de confinement du plomb et du cadmium dans des verres à base de métaphosphates de zinc


    El Hadrami, Abdelouahab


    This study fits into the investigation of new phosphate glasses with optimal physical and chemical properties as part of storage of heavy toxic metals such as Pb and Cd. Glasses using (100-x) (50P2O5-15ZnO-35PbO)-xFe2O3 and (100-z) [50P2O5-15ZnO-(35-y)PbO-yCdO]-zAl2O3, mol%, batch composition have been synthesized. The addition of iron and aluminium oxides in the based phosphate glasses induces an improvement of the properties, in particular the aqueous corrosion resistance, which is comparab...

  14. Modeling of an electric arc transferred on a melted glass bath; Modelisation d`un arc electrique transfere sur un bain de verre

    Energy Technology Data Exchange (ETDEWEB)

    Mehlman, G.; Langlois, A. [SGN, 78 - Saint Quentin en Yvelines (France)


    The aim of this study is to propose a methodology allowing the simulation of melting processes involving electromagnetic phenomena. This methodology is based on the use of scientific calculation tools currently used elsewhere. The case considered in this study has been defined in collaboration with Electricite de France (EdF) and concerns more particularly an electric arc vitrification process for wastes. Basic data have been determined in order to obtain results representative of the tests performed by EdF with pilot installations. (J.S.)

  15. Water leaching of borosilicate glasses: experiments, modeling and Monte Carlo simulations; Alteration par l'eau des verres borosilicates: experiences, modelisation et simulations Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Ledieu, A


    This work is concerned with the corrosion of borosilicate glasses with variable oxide contents. The originality of this study is the complementary use of experiments and numerical simulations. This study is expected to contribute to a better understanding of the corrosion of nuclear waste confinement glasses. First, the corrosion of glasses containing only silicon, boron and sodium oxides has been studied. The kinetics of leaching show that the rate of leaching and the final degree of corrosion sharply depend on the boron content through a percolation mechanism. For some glass contents and some conditions of leaching, the layer which appears at the glass surface stops the release of soluble species (boron and sodium). This altered layer (also called the gel layer) has been characterized with nuclear magnetic resonance (NMR) and small angle X-ray scattering (SAXS) techniques. Second, additional elements have been included in the glass composition. It appears that calcium, zirconium or aluminum oxides strongly modify the final degree of corrosion so that the percolation properties of the boron sub-network is no more a sufficient explanation to account for the behavior of these glasses. Meanwhile, we have developed a theoretical model, based on the dissolution and the reprecipitation of the silicon. Kinetic Monte Carlo simulations have been used in order to test several concepts such as the boron percolation, the local reactivity of weakly soluble elements and the restructuring of the gel layer. This model has been fully validated by comparison with the results on the three oxide glasses. Then, it has been used as a comprehensive tool to investigate the paradoxical behavior of the aluminum and zirconium glasses: although these elements slow down the corrosion kinetics, they lead to a deeper final degree of corrosion. The main contribution of this work is that the final degree of corrosion of borosilicate glasses results from the competition of two opposite mechanisms : the rapid extraction of the soluble species and the reconstruction of the passivating altered layer. (author)

  16. Aqueous corrosion of borosilicate glasses: experiments, modeling and Monte-Carlo simulations; Alteration par l'eau des verres borosilicates: experiences, modelisation et simulations Monte-Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Ledieu, A


    This work is concerned with the corrosion of borosilicate glasses with variable oxide contents. The originality of this study is the complementary use of experiments and numerical simulations. This study is expected to contribute to a better understanding of the corrosion of nuclear waste confinement glasses. First, the corrosion of glasses containing only silicon, boron and sodium oxides has been studied. The kinetics of leaching show that the rate of leaching and the final degree of corrosion sharply depend on the boron content through a percolation mechanism. For some glass contents and some conditions of leaching, the layer which appears at the glass surface stops the release of soluble species (boron and sodium). This altered layer (also called the gel layer) has been characterized with nuclear magnetic resonance (NMR) and small angle X-ray scattering (SAXS) techniques. Second, additional elements have been included in the glass composition. It appears that calcium, zirconium or aluminum oxides strongly modify the final degree of corrosion so that the percolation properties of the boron sub-network is no more a sufficient explanation to account for the behavior of these glasses. Meanwhile, we have developed a theoretical model, based on the dissolution and the reprecipitation of the silicon. Kinetic Monte Carlo simulations have been used in order to test several concepts such as the boron percolation, the local reactivity of weakly soluble elements and the restructuring of the gel layer. This model has been fully validated by comparison with the results on the three oxide glasses. Then, it has been used as a comprehensive tool to investigate the paradoxical behavior of the aluminum and zirconium glasses: although these elements slow down the corrosion kinetics, they lead to a deeper final degree of corrosion. The main contribution of this work is that the final degree of corrosion of borosilicate glasses results from the competition of two opposite mechanisms : the rapid extraction of the soluble species and the reconstruction of the passivating altered layer. (author)

  17. Modelling of nuclear glasses by classical and ab initio molecular dynamics; Modelisation de verres intervenant dans le conditionnement des dechets radioactifs par dynamiques moleculaires classique et ab initio

    Energy Technology Data Exchange (ETDEWEB)

    Ganster, P


    A calcium aluminosilicate glass of molar composition 67 % SiO{sub 2} - 12 % Al{sub 2}O{sub 3} - 21 % CaO was modelled by classical and ab initio molecular dynamics. The size effect study in classical MD shows that the systems of 100 atoms are more ordered than the larger ones. These effects are mainly due to the 3-body terms in the empirical potentials. Nevertheless, these effects are small and the structures generated are in agreement with experimental data. In such kind of glass, we denote an aluminium avoidance and an excess of non bridging oxygens which can be compensated by tri coordinated oxygens. When the dynamics of systems of 100 and 200 atoms is followed by ab initio MD, some local arrangements occurs (bond length, angular distributions). Thus, more realistic vibrational properties are obtained in ab initio MD. The modelling of thin films shows that aluminium atoms extend to the most external part of the surface and they are all tri-coordinated. Calcium atoms are set in the sub layer part of the surface and they produce a depolymerization of the network. In classical MD, tri-coordinated aluminium atoms produce an important electric field above the surface. With non bridging oxygens, they constitute attractive sites for single water molecules. (author)

  18. heT BoeK PrediKer: een verrAssende en uiTdAgende sTem in de ...

    African Journals Online (AJOL)

    koning salomo. enerzijds is deze gebaseerd op het opschrift van het boek, dat qohelet 'zoon van david' en 'koning in Jeruzalem' noemt (Pr 1,1), en anderzijds leidt qohelet zelf de beschrijving van zijn grootse ondernemingen als koning in de eerste hoofdstukken in met het weinig aan de verbeelding overlatende 'ik, qohelet ...

  19. Le vieil homme et la cage de verre : Adolf Eichmann et la migration d'une iconographie sous-et surdéterminée


    Matthias Steinle


    International audience; This article discusses the image of Adolf Eichmann, which has haunted the screen ever since his spectacular kidnapping in Argentina. Characterized by a lack of archive images from the Nazi era and an abundance of images from the trial in Jerusalem in 1962, the man in the glass booth is an interesting example of the role of archive images in cultural memory and the mediality of history. Eichmann as a “media phenomenon” is analysed in his different dimensions: first a se...

  20. Synthesis on the durability of composite fiberglass/epoxy resin structures; Synthese sur la durabilite des structures composites en fibres de verre/resine epoxide

    Energy Technology Data Exchange (ETDEWEB)

    Thevenin, P. [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)


    The purpose of this paper is to collect together in a systematic way information and results relating to the durability of composite fiberglass/ epoxy resin structures. First it is a matter of assessing the average level of understanding the long term behaviour of these structures which change under the combined effects of varied mechanical loading and stresses of a physico-chemical type linked to the environment. Looking at phenomena encountered and facts from current analyses, it will then be advisable to specify a methodology which can be applied to industrial piping used in PWR cooling systems for transporting raw water under pressure. In fact assessment of their service life is at present based on long and costly testing (ASTM D 2992 B standard), the appearance of which is inherited from metal piping testing.. Therefore it appears essential to study substitution test procedures, more composite specific and at the same time which can be conducted in reasonable time. For this purpose, by coherently accelerating and combining them in order not to underestimate their effects, ageing tests shall reproduce mechanisms representative of operating conditions. (author). 113 refs.

  1. Thermal stability of the French nuclear waste glass - long term behavior modeling; Etude de la stabilite thermique du verre nucleaire. Modelisation de son evolution a long terme

    Energy Technology Data Exchange (ETDEWEB)

    Orlhac, X


    The thermal stability of the French nuclear waste glass was investigated experimentally and by modeling to predict its long-term evolution at low temperature. The crystallization mechanisms were analyzed by studying devitrification in the supercooled liquid. Three main crystalline phases were characterized (CaMoO{sub 4}, CeCO{sub 2}, ZnCr{sub 2}O{sub 4}). Their crystallisation was TO 4.24 wt%, due to the low concentration of the constituent elements. The nucleation and growth curves showed that platinoid elements catalysed nucleation but did not affect growth, which was governed by volume diffusion. The criteria of classic nucleation theory were applied to determine the thermodynamic and diffusional activation energies. Viscosity measurements illustrate the analogy between the activation energy of viscous flow and diffusion, indicating control of crystallization by viscous flow phenomena. The combined action of nucleation and growth was assessed by TTT plots, revealing a crystallization equilibrium line that enables the crystallized fractions to be predicted over the long term. The authors show that hetero-genetics catalyze the transformation without modifying the maximum crystallized fraction. A kinetic model was developed to describe devitrification in the glass based on the nucleation and growth curves alone. The authors show that the low-temperature growth exhibits scale behavior (between time and temperature) similar to thermo-rheological simplicity. The analogy between the resulting activation energy and that of the viscosity was used to model growth on the basis of viscosity. After validation with a simplified (BaO{sub 2}SiO{sub 2}) glass, the model was applied to the containment glass. The result indicated that the glass remained completely vitreous after a cooling scenario with the one measured at the glass core. Under isothermal conditions, several million years would be required to reach the maximum theoretical crystallization fraction. (author)

  2. Study of nuclear glasses alteration gel and synthesis of some model gels; Etude du gel d`alteration des verres nucleaires et synthese de gels modeles

    Energy Technology Data Exchange (ETDEWEB)

    Ricol, S.


    This work deals with the general problem of alteration of the reference nuclear glass R7T7. Attention is paid particularly to the altered layer formed at the glass surface during alteration process. In opposition to previous works, related essentially to glass dissolution kinetics based on chemical analyses of lixiviated elements, this thesis deals with alteration problems through structural studies of the reference glass and derived gel. This approach allows the determination of mechanisms for the gel formation and a better understanding of the behaviour of glasses towards lixiviation. Both approaches appeared complementary. Based on several spectroscopic techniques, this work showed the particular role of cations such as calcium, zirconium and iron. Studies of silica-based synthetic gels showed the synergic effect of formers cation and of one highly coordinated cation. The variation of the wavenumber related to Si-O-Si asymmetric stretching vibration can be correlated to O/Si ratio for ternary systems Si/Na/Zr. On the contrary, the Si losses of the materials depend on the number of non-bridging oxygen atoms. In the perspective of long-term behaviour, the alteration gel presents better characteristics than initial glass. It is therefore a highly stable material in static conditions. In the same way, synthetic gels are materials with very low solubilities (much lower than the alteration gel) and could be used as confining matrices. (authors). refs., 71 figs., 37 tabs.

  3. Optimisation structurale de dalles de chaussees en beton jointees avec des goujons en materiaux composites en Polymeres Renforces de Fibres de Verre (PRFV) (United States)

    Bricola, Julien

    In Quebec, the majority of the road network was built in the 60's - 70's and show obvious signs of ageing. Moreover, the increase of road traffic and the rigorous weather conditions, render the maintenance and the exploitation of roads in this Northern American part quite difficult. Indeed, these environmental conditions cause severe damages for roads, especially in winter. The degradation factor of the jointed rigid pavement is intensified by the highway salt. So, the phenomena of deteriorations appears mainly by the corrosion of the steel at the joints (structural elements) guaranteeing the durability of roads. The jointed rigid pavements or "short jointed pavements" are still mainly sized with steel dowels placed at the lining of joints. One of the main functions of these structures is to control the formation of cracking due to the thermal and environmental conditions. In order to reduce these , disorders, the Ministry of Transport of Quebec (MTQ) turned towards new techniques and innovative materials to ensure the longevity of roads. With the rapid evolution of specific methods and knowledge in roads design, joined with technologies and new products, the MTQ emphasizes the research and development. That way, advanced techniques and diverse technologies in the Quebecois context are settled. As a matter of fact, one of the axes of these development researches concerns the composite materials which have recently been given good results in the civil engineering area. That is why Glass Fibre-Reinforced Polymer (GFRP) dowels bars appear as a solution to the steel corrosion. In fact, they provide better durability with lower costs: the increase of service life as well as the decrease of maintenance persons and traffics impac. Thus, this project proposes an optimization of structural design of GFRP dowels for transverse jointed highway pavement slabs, also keeping in mind their use in new projects. The GFRP dowels which are given in this essay are made by the Pultrall Inc. Company from Thetford Mines (Quebec, Canada). The resin used for the polymer materials is only vinylester resin and the dowels have diameters going from 28.6 mm to 34.9 mm. Finally, only a stiff base is used for the road, its particularity is the modulus of subgrade reaction. Keywords: concrete pavement, dowelled slab, jointed concrete pavement, GFRP dowels, optimization, structural, design .

  4. Etude des effets du climat nordique sur la duree de vie en fatigue en tension des composites unidirectionnels de fibres de verre et d'epoxy (United States)

    Brassard, David

    Northern regions of Canada present a huge potential for wind energy production. Unfortunately, it introduces new challenges regarding the operating conditions. This thesis presents a study on the effects of northern climate on the fatigue life of unidirectional glass fibre/epoxy composites. Following a review of previous researches in that field, we provide the results of the present study. Under controlled experimental conditions, we examined the individual and combined effects of low temperatures, moisture content, and freeze-thaw cycles on the fatigue life under tension load of composites. These results were compared to dry and room temperature conditions that served as a baseline. Statistical analysis suggests that thermal cycles between 40 °C and -40 °C do not affect the average fatigue life of unidirectional composites. Freeze-thaw cycles detrimentally affects the interface observed after failure of the specimens. At high stresses, moisture content decreases fatigue life while at low stresses, moisture content increases fatigue life probably due to an increase in ductility of the epoxy matrix. Low temperature did not affect the fatigue life of dry samples, but increased the fatigue life of specimens for moisture conditioned samples. In dry conditions, Northern climates do not negatively affect the fatigue life of unidirectional composites. Freeze-thaw cycles also did not affect fatigue life of unidirectionnal composites. Future research should test its effect on the interface in multidirectional composites.

  5. « Un homme posant son regard sur le verre » : Éric Rohmer et David Hockney


    Dixon, Simon


    L’une des questions fondamentales qui se posent aux réalisateurs de la Nouvelle Vague porte sur l’ambition esthétique d’un film, sur son statut en tant qu’art. Où se trouve cet art chez Éric Rohmer ? D’une manière générale, il se cache dans l’ordinaire, le quotidien. Je voudrais utiliser ici le travail de l’artiste britannique David Hockney pour mettre au jour cet art caché ; utiliser sa peinture pour révéler le caractère unique de l’esthétique cinématographique de Rohmer. Le thème de la pein...

  6. Solubility of actinides and surrogates in nuclear glasses; Solubilite des actinides et de leurs simulants dans les verres nucleaires. Limites d'incorporation et comprehension des mecanismes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Ch


    The nuclear wastes are currently incorporated in borosilicate glass matrices. The resulting glass must be perfectly homogeneous. The work discussed here is a study of actinide (thorium and plutonium) solubility in borosilicate glass, undertaken to assess the extent of actinide solubility in the glass and to understand the mechanisms controlling actinide solubilization. Glass specimens containing; actinide surrogates were used to prepare and optimize the fabrication of radioactive glass samples. These preliminary studies revealed that actinide Surrogates solubility in the glass was enhanced by controlling the processing temperature, the dissolution kinetic of the surrogate precursors, the glass composition and the oxidizing versus reducing conditions. The actinide solubility was investigated in the borosilicate glass. The evolution of thorium solubility in borosilicate glass was determined for temperatures ranging from 1200 deg C to 1400 deg C.Borosilicate glass specimens containing plutonium were fabricated. The experimental result showed that the plutonium solubility limit ranged from 1 to 2.5 wt% PuO{sub 2} at 1200 deg C. A structural approach based on the determination of the local structure around actinides and their surrogates by EXAFS spectroscopy was used to determine their structural role in the glass and the nature of their bonding with the vitreous network. This approach revealed a correlation between the length of these bonds and the solubility of the actinides and their surrogates. (author)

  7. Souffleurs de verre, mémoires intimes « au travail »  Glassblowers, private memories « at work »

    Directory of Open Access Journals (Sweden)

    Marie-Ange Lasmènes


    Full Text Available Le recueil de mémoires réalisé à l’occasion d’une enquête ethnographique auprès de verriers montre l’intérêt d’observer le changement au sein d’une entreprise porteuse de projets à la fois artistiques, sociaux et politiques. Après avoir montré l’intérêt pour l’ethnologue d’étudier la mémoire dans une perspective diachronique et le jeu de temporalité qui s’en dégage, il s’agira d’exposer en quoi la patrimonialisation des métiers relatifs à l’artisanat d’art ouvre vers une nouvelle catégorie patrimoniale à la croisée entre des politiques nationales et le développement d’un sentiment identitaire local autour de ce secteur d’activité exprimé par des discours officiels comme par un ensemble de mémoires individuelles. Enfin, sans rechercher à retracer une vérité historique du passé, il s’agira de présenter certains éléments de mémoires intimes autour du travail en entreprise rendus tacites par le changement de contexte entrepreneurial et la réappropriation d’une mémoire « officielle ».Glassblowers’ collect of memories realized during an ethnographic investigation shows the interest to observe how a firm holding artistic, social and politic projects can change. After have shown the interest for the ethnologist to study memory in a diachronical way dealing with its temporality, it will be exposed how patrimonialisation of handcrafts offers a new category of heritage localized between national politics and the expansion of a local feeling of identity linked to this corporation expressed by official talks and individual memories. Finally, far from a search of a historical truth of past, some elements of private memories at work, in a glass firm, hidden by the change of an entrepreneurial context and the assimilation of an official memory, will be presented.

  8. Platinoids and molybdenum in nuclear waste containment glasses: a structural study; Les platinoides et le molybdene dans des verres d'interet nucleaires: etude structurale

    Energy Technology Data Exchange (ETDEWEB)

    Le Grand, M. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification (DRRV), 30 - Marcoule (France)]|[Paris-7 Univ., 75 (France)


    This work deals with the structure of borosilicate nuclear glasses and with some relationships between structure and macroscopic properties. Two types of elements which may disturb the industrial process - platinoids (Ru and Pd) and molybdenum - are central to this work. Platinoids induce weak modifications on the structure of the glass, causing a depolymerization of the glassy network, an increase of the {sup [3]}B/{sup [4]}B ratio and a modification of the medium range order around Si between 3.3 and 4.5 angstrom. The modifications of viscosity and density induced by platinoids in the glass are not due to the structural effect of the platinoids. The increase of viscosity is attributed to needle shaped RuO{sub 2}. It can be moderated by imposing reducing conditions during the elaboration of the glass. The slight difference between experimental and calculated densities is due to the increase of the volume percentage of bubbles in the glass with increasing platinoid content. Mo is either present in the glass as molybdic groupings, or mobilized in chemically complex molybdic crystalline phases. The chemical composition and mineralogy of these phases has been obtained using electronic microprobe data and XRD with Rietveld analysis. The distribution of the different elements between the crystalline phases and the glass is strongly influenced by the structural role of the various cations in the glass. The Mo present in the glass appears as MoO{sub 4} tetrahedra, independent of the borosilicate network. The formation of the crystalline phases can be explained by the existence of a precursor in which the MoO{sub 4} tetrahedra are concentrated in rich alkali and earth-alkali bearing areas of the glass. (author)

  9. Comparative evaluation of glasses reprocessing and reversible conditioning of calcinates; Evaluation comparative de la reprise des verres et du conditionnement reversible des calcinats

    Energy Technology Data Exchange (ETDEWEB)

    Boen, R


    Fission products and minor actinides separated during the spent fuel reprocessing treatment are industrially vitrified on-line and thus confined inside a glass matrix with admittedly durability properties. In the framework of the feasibility of a reversible conditioning, this document examines first the possible alternative ways of conditioning and storage of calcinates before vitrification, which may simplify the reversibility aspect. Such a conditioning must be compatible with the storage process, with a possible extraction of actinides and long-lived fission products, and with the vitrification process if no extraction is performed. Calcinates are pulverulent and comprise an important soluble fraction, a proportion of nitrates of about 30%, and release a high thermal power (17 kW/m{sup 3}) combined to a low thermal conductivity (0.1 to 0.15 W.m{sup -1} k{sup -1}). Among the different foreseeable solutions (denitration, mixing with another material, with or without compacting, dissolution inside another material..), the dissolution inside a borate seems to be the most acceptable with respect to the safety, feasibility and vitrification aspects. The thermal aspect of the storage remains complex as a specific container is necessary. In a second part, this report analyzes the possibility to re-extract back the long-lived radionuclides from vitrified wastes. The different possible ways to destroy the glass structure and to transfer the fission products and minor actinides in an aqueous solution compatible with an hydrometallurgical separation process are explored. Two processes are foreseeable: a low temperature dissolution process which requires a preliminary crushing and the handling of huge amounts of acids, and a both high and low temperature process which comprises the following steps: melting, fractionation by water tempering, addition of Na{sub 2}O or sodium tetraborate to make it sensible to hot leaching, separation of fission products and minor actinides, recycling of reagents, and vitrification of secondary wastes. This last process is the most feasible as it is accessible to existing technologies but its industrialization would require important developments. (J.S.)

  10. Effect of alumina on the dissolution rate of glasses; Role de l'alumine sur la vitesse initiale de dissolution des verres

    Energy Technology Data Exchange (ETDEWEB)

    Palavit, G.; Montagne, L. [Ecole Nationale Superieure de Chimie de Lille, Lab. de Cristallochimie et Physicochimie du Solide, URA CNRS 0452, 59 - Villeneuve d' Ascq (France)


    Small alumina addition to silicate glasses improves their chemical durability, but a large amount of alumina can also be beneficial to obtain a high dissolution rate. This paper describes the effect of Al{sup 3+} on the early stage of glass alteration, in relation with its coordination in the glass and also with the reactions involved (hydrolysis and ionic exchange). We describe briefly nuclear magnetic resonance tools available to characterize the aluminum environments in the glasses. The rote of alumina on the dissolution rate of phosphate glasses is also discussed in order to show that the effect of Al{sup 3+} is dependant upon the nature of the glass matrix. (author)

  11. Use of archaeological glasses leached in sea water for modelling the long-time behaviour of nuclear glasses in condition of deep geological storage; De l'utilisation des verres archeologiques alteres en milieu marin pour modeliser le comportement a long terme des verres nucleaires en condition de stockage geologique profond

    Energy Technology Data Exchange (ETDEWEB)

    Verney-Carron, A. [Institut National Polytechnique, 54 - Nancy (France)]|[CEA Valrho, Lab. d' Etudes du Comportement a Long Terme des Materiaux de Conditionnement (LCLT), 30 - Marcoule (France)


    The archaeological glasses studied in this thesis are blocks of some kilograms which come from a wreck stranded at 56 m of depth off the Embiez islands. Their composition are silico-sodo-calcic. They have been at a constant temperature of 12 C during 1800 years and are therefore leached. The main analogy between these objects and the nuclear glasses is the morphology of the blocks. Indeed, they have been both submitted to a fast cooling and on account of their brittle character, cracks have been formed and propagated to dissipate their mechanical stresses. Thus, an internal surface accessible to water has been formed. The accurate quantification of the contribution of the internal surfaces to the global alteration of the nuclear glass blocks in disposal is difficult because the performance and safety models depends to it. The surfaces accessible to water at the initial time have to be considered and then, a potential evolution of these surfaces during time and under the effect of thermal, chemical and mechanical stresses are to be considered. Therefore, cracks can clog up by the formation of mineral phases or open under the effect of external stresses effect. The archaeological analogues can then be interesting to make these scenarios. The experimental approach is described here and explained. (O.M.)

  12. Stress Corrosion of Ceramic Materials. (United States)


    Scientifique Continentale du Verre , Charleroi, Belgium, 1962. Dunning, J.M., Effects of Aqueous Chemical Environments on Crack Propagation in Quartz, this volume...Symposium on Mechanical Strength of Glass and Ways of Improving It. Florence, Italy, September 25-29, 1961. Union Scientifique Continentale du Verre ...Florence, Italy, September 25-29, 1961. Union Scientifique Continentale du Verre , Charleroi, Belgium, 1962., 24. T.A. Michalske, "The Stress

  13. Study of the performances of acoustic emission testing for glass fibre reinforced plastic pipes containing defects; Etude des performances du controle par emission acoustique de tubes en materiaux composites resine-fibre de verre contenant des defauts

    Energy Technology Data Exchange (ETDEWEB)

    Villard, D.; Vidal, M.C.


    Glass fibre reinforced plastic pipes are more and more often used, in nuclear power plants, for building or replacement of water pipings classified `nuclear safety`. Tests have been performed to evaluate the performances of acoustic emission testing for in service inspection of these components. The tests were focused on glass fibre reinforced polyester and vinyl-ester pipes, in as received conditions or containing impacts, and intentionally introduced defects. They have been carried out by CETIM, following the ASTM Standard E 1118 (code CARP), to a maximum pressure lever of 25 Bar The results show that the CARP procedure can be used for detection of defects and evaluation of their noxiousness towards internal pressure: most of the tubes containing low energy impacts could not be distinguished from tubes without defect; on the other hand the important noxiousness of lacks of impregnation of roving layer appeared clearly. Complementary tests have been performed on some tubes at a more important pressure lever, for which the damage of the tubes in enough to deteriorate there elastic properties. The results showed that CARP procedure give valuable informations on damage level. It would be interesting to evaluate acoustic emission on tubes containing realistic in-service degradations. (author). 11 refs., 15 figs., 6 tabs., 2 appends.

  14. Numerical modelling of coupled phenomena within molten glass heated by induction and mechanically stirred; Modelisation numerique de phenomenes couples dans des bains de verre brasses mecaniquement et elabores en creuset froid inductif

    Energy Technology Data Exchange (ETDEWEB)

    Jacoutot, L


    This study reports on a new vitrification process developed by the French Atomic Energy Commission (CEA, Marcoule). This process is used for the treatment of high activity nuclear waste. It is characterized by the cooling of all the metal walls and by currents directly induced inside the molten glass. In addition, a mechanical stirring device is used to homogenize the molten glass. The goal of this study is to develop numerical tools to understand phenomena which take place within the bath and which involve thermal, hydrodynamic and electromagnetic aspects. The numerical studies are validated using experimental results obtained from pilot vitrification facilities. (author)

  15. Doping influence by some transition elements on the irradiation effects in nuclear waste glasses; Influence du dopage par certains elements de transition sur les effets d'irradiation dans des verres d'interet nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Florent, Olivier


    High-level waste glasses are submitted to auto-irradiation. Modelling it using external irradiations on simple glasses revealed defects production and non negligible structural changes. This thesis aims at determining the impact of a more complex composition on these effects, especially the influence of adding polyvalent transition metals. Silicate, soda-lime and alumino-borosilicate glasses are doped with different iron, chromium and manganese concentrations then {beta} irradiated at different doses up to 10{sup 9} Gy. Non doped glasses show an increase of their density and polymerisation coupled with a molecular oxygen and point defects production. Adding 0.16 mol% Fe decreases the amount of defects by 85 % and all irradiation effects. A Fe{sup 3+} reduction is also observed by EPR, optical absorption and indirectly by Raman spectroscopy. A higher than 0.32 mol% Fe concentration causes complete blockage of the evolution of polymerisation, density and defect production. The same results are obtained on chromium or manganese doped glasses. An original in situ optical absorption device shows the quick decrease of Fe{sup 3+} amount to a 25 % lower level during irradiation. Stopping irradiation causes a lower decrease of 65 %, suggesting a dynamic (h{sup 0}/e-) consuming equilibrium. He{sup +} and Kr{sup 3+} ions and {gamma} irradiated glasses tend to confirm these phenomena for all kind of irradiation with electronic excitations. (author)

  16. Structure and aqueous reactivity of silicate glasses high-resolution nuclear magnetic resonance contribution; Structure et reactivite aqueuse des verres silicates apport de la resonance magnetique nucleaire haute-resolution

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, F


    This research aims at getting a better understanding of the relations which may exist between the chemical composition of the oxide silicate glasses, the structure and the aqueous reactivity. We study the cations present in most glasses, more particularly the radioactive waste glasses, and those which are more liable to bring information both about structure and reactivity. Among the experimental methods used, the nuclear magnetic resonance of multi-quantum magic-angle spinning (NMR MQ-MAS) has been carried out for the structural characterization of the pristine and altered glasses. In the first part, we discuss the possibility of deducting a type of information from a quantitative approach of the {sup 23}Na, {sup 27}Al and {sup 17}O NMR MQ-MAS. In the second part, we apply this method to glasses containing between two and six oxides. The vitreous compositions studied permit to focus our attention on the influence of sodium, aluminum and calcium on their local structural environment. We point out an evolution of the distributions of bond distances and angles in relation to the glass chemical composition. We show the strong potentiality of the {sup 17}O used to probe the pristine and altered glasses. The influence of the different cations studied on the rate of glass dissolution is debated from the alterations made on short periods. On the basis of all these data, we discuss the importance of the structural effect which may influence the kinetic phenomena of alteration. (author)

  17. Évaluation d’un module électro-optique hybride combinant la photonique sur silicium et sur verre pour des applications de multiplexage en longueur d’onde (WDM)


    Ayi-Yovo, Folly Eli


    The ever-increasing demand for telecommunications needs has highlighted the intrinsic limitations of electronics. Photonics has proven to be a suitable solution to its limitations. STMicroelectronics has developed a silicon photonic platform called PIC25G that allows single-channel transmission at 25 Gb/s. The data rate increase with wavelength division multiplexing (WDM) encounter some constraints. The proposed solution is based on a hybrid approach integrating silicon photonics and glass io...

  18. Structural and crystallisation study of a rare earth alumino borosilicate glass designed for nuclear waste confinement; Etude de la structure et du comportement en cristallisation d'un verre nucleaire d'aluminoborosilicate de terre rare

    Energy Technology Data Exchange (ETDEWEB)

    Quintas, A


    This work is devoted to the study of a rare earth alumino borosilicate glass, which molar composition is 61,81 SiO{sub 2} - 3,05 Al{sub 2}O{sub 3} - 8,94 B{sub 2}O{sub 3} - 14,41 Na{sub 2}O - 6,33 CaO - 1,90 ZrO{sub 2} - 3,56 Nd{sub 2}O{sub 3}, and envisaged for the immobilization of nuclear wastes originating from the reprocessing of high discharge burn up spent fuel. From a structural viewpoint, we investigated the role of the modifier cations on the arrangement of the glass network through different modifications of the glass composition: variation of the Na/Ca ratio and modification of the nature of the alkali and alkaline earth cations. The NMR and Raman spectroscopic techniques were useful to determine the distribution of modifier cations among the glass network and also to cast light on the competition phenomena occurring between alkali and alkaline earth cations for charge compensation of [AlO{sub 4}]{sup -} and [BO{sub 4}]{sup -} species. The neodymium local environment could be probed by optical absorption and EXAFS spectroscopies which enabled to better understand the insertion mode of Nd{sup 3+} ions among the silicate domains of the glass network. Concerning the crystallization behavior we were interested in how the glass composition may influence the crystallization processes and especially the formation of the apatite phase of composition Ca{sub 2}Nd{sub 8}(SiO{sub 4}){sub 6}O{sub 2}. In particular, this work underlined the important role of both alkaline earth and rare earth cations on the crystallization of the apatite phase. (author)

  19. Smoke filtration in the glass industry. Thomson Videoglass` global approach with closed loop recycling; Fitration des fumees dans l`industrie du verre. L`approche globale avec recyclage en boucle fermee de thomson videoglass

    Energy Technology Data Exchange (ETDEWEB)

    Mocek, L. [Thomson Videoglass, 77 - Bagneaux-sur-Loing (France)


    Thomson Videoglass, an ISO 9002 certified manufacturer of glass components for Tv sets in France, has introduced a global closed-loop recycling dust filtration system for glass kilns; electrostatic filters and bag filters (for the lead-containing flat glass kiln) have been selected and collected dusts are recycled in the cone glass kiln. Energy savings, operating conditions, investment and operating costs are discussed together with filter corrosion, clogging-up and service life issues and dust extraction performances

  20. Luminescence of devitrificated non-doped and Eu,Dy and Tm doped wollastonite crystal in glass; Luminescence de cristaux de devitrivication de wollastonite dans des verres non dopes et dopes en Eu,Dy et Tm

    Energy Technology Data Exchange (ETDEWEB)

    El Marraki, A.; Schvoerer, M.; Bechtel, F. [Univ. Michel de Montaigne-Bordeaux 3, Pessac (France). Centre de Recherche en Phys. Appliquee a l' Archeologie


    Wollastonite crystals (CaSiO{sub 3}), ''pure'' or doped with rare earth ions, were grown by a devitrification process of a ternary SiO{sub 2}-Na{sub 2}O-CaO glass. The nature of point defects in these crystals was studied. Concerning the non-doped crystals, two trap centers were revealed by thermoluminescence (TL) and identified by electron spin resonance (ESR) using preheating experiments: one is a hole center HC{sub 1} and the other one an electron center whose main characteristic feature is g = 2.0020. Cathodoluminescence (CL) studies showed an important emission band considered as intrinsic. As for the doped crystals (Eu, Dy, Tm), most CL emission bands were identified. With TL, it is shown that Eu acts in wollastonite crystals as an electron trap and also as an emission centre. (orig.)

  1. Study of archaeological analogs for the validation of nuclear glass long-term behavior models; Etude d'analogues archeologiques pour la validation des modeles de comportement a long terme des verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Verney-Carron, A


    Fractured archaeological glass blocks collected from a shipwreck discovered in the Mediterranean Sea near Embiez Island (Var) were investigated because of their morphological analogy with vitrified nuclear waste and of a known and stable environment. These glasses are fractured due to a fast cooling after they were melted (like nuclear glass) and have been altered for 1800 years in seawater. This work results in the development and the validation of a geochemical model able to simulate the alteration of a fractured archaeological glass block over 1800 years. The kinetics associated with the different mechanisms (interdiffusion and dissolution) and the thermodynamic parameters of the model were determined by leaching experiments. The model implemented in HYTEC software was used to simulate crack alteration over 1800 years. The consistency between simulated alteration thicknesses and measured data on glass blocks validate the capacity of the model to predict long-term alteration. This model is able to account for the results from the characterization of crack network and its state of alteration. The cracks in the border zone are the most altered due to a fast renewal of the leaching solution, whereas internal cracks are thin because of complex interactions between glass alteration and transport of elements in solution (influence of initial crack aperture and of the crack sealing). The lowest alteration thicknesses, as well as their variability, can be explained. The analog behavior of archaeological and nuclear glasses from leaching experiments makes possible the transposition of the model to nuclear glass in geological repository. (author00.

  2. Experimental investigation of the effects of aqueous species on the dissolution kinetics of R7T7 glass; Etude experimentale de l`influence d`especes aqueuses sur la cinetique de dissolution du verre nucleaire R7T7

    Energy Technology Data Exchange (ETDEWEB)

    Gin, S.


    This contribution to the study of aqueous corrosion of the French ``R7T7`` reference nuclear containment glass includes a bibliographic survey of prior investigations, highlighting the problems encountered in interpreting the interactions in systems containing clay materials in contact with the glass. An experimental methodology is proposed to investigate the effects of inorganic aqueous species separately from those of a few organic acids on the dissolution mechanisms and kinetics of R7T7 glass at 90 deg. C. The experimental results discussed support the idea that several glass network forming elements may have a kinetically limiting role. The most likely hypothesis to account for the absence of saturation conditions with respect to the glass in certain clay media involves the formation of complexes with kinetically limiting metallic elements such as aluminum released by glass corrosion. This work contributes to a better understanding of the basic mechanisms of nuclear glass dissolution in a geological repository environment. It facilitates the interpretation of glass alteration studies in realistic or actual solutions and may contribute to specifying near field chemical barriers in the form of additives (amorphous silica, aluminum hydroxides or phosphates) around the glass disposal package to enhance the stability of the glass matrix. (author). 148 refs., 40 figs., 32 tabs., 1 append.

  3. Catalyze and chemical inhibition of the R7T7 glass kinetics; Catalyse et inhibition de la cinetique d'alteration du verre de reference eau legere R7T7

    Energy Technology Data Exchange (ETDEWEB)

    Gin, St.; Advocat, Th. [CEA Valrho, Dir. de l' Energie Nucleaire, DEN, 30 - Marcoule (France)


    This article highlights some phenomena likely to modify the glass alteration kinetics and/or the nature of the alteration products according to the chemical composition of the leaching water. It discusses experimental results showing that in neutral and basic media, the presence of inorganic anions or organic acid (simple carboxylic acid and humic acid) has relatively little effect on the long-term glass matrix alterability Actinide mobility appears to be more dependent on the concentration of complexing agents in the leaching solution. The behavior of phosphate ions, which may inhibit or catalyze the R7T7 glass alteration kinetics depending on the experimental conditions, is discussed; the gel microstructure can be related to the glass alteration kinetics by detailed examination of the alteration products. (authors)

  4. Self-defects and self diffusion in a silica glass: a first-principles study; Etude ab-initio des auto-defauts et des mecanismes d'auto-diffusion dans un verre de silice

    Energy Technology Data Exchange (ETDEWEB)

    Martin, L.; Colomer, S


    SiO{sub 2} and silica based compounds are key materials in a variety of scientific and technological fields as, for instance, in microelectronics or nuclear technology. In all these fields, one of the still open questions is their long term aging in a radioactive environment. Due to the complexity of the effects of radiations upon matter, the understanding of the long term aging needs the knowledge of diffusion mechanisms at the atomic scale. In that context, numerical modelling appears as a way to access this scale. We present a first principles study on self-defects and self-diffusion in a silica model. As expected, at variance with SiO{sub 2} crystalline phases, the defects formation energies are distributed, due to the non-equivalence of defects sites. We prove that the formation energy dispersion is correlated to the local stress. Concerning the equilibrium concentrations and oxygen diffusion mechanism, we discuss how the shape of the distribution, as well as impurity levels within the gap, play a main role in the dominance of defect types. Finally we present the main oxygen diffusion mechanism in homogeneous and heterogeneous defect formation regime. (author)

  5. Structure and properties of rare earth-rich glassed for nuclear waste immobilisation; Etude des caracteristiques structurales et des proprietes de verres riches en terres rares destines au confinement des produits de fission et elements a vie longue

    Energy Technology Data Exchange (ETDEWEB)

    Bardez, I


    A new nuclear glass composition, able to immobilize highly radioactive liquid wastes from high burn-up UO{sub 2} fuel, was established and its structure studied. The composition of the selected rare earth-rich glass is (molar %): 61.79 SiO{sub 2} - 8.94 B{sub 2}O{sub 3} - 3.05 Al{sub 2}O{sub 3} - 14.41 Na{sub 2}O - 6.32 CaO - 1.89 ZrO{sub 2} - 3.60 RE{sub 2}O{sub 3} (with RE = La, Ce, Pr and Nd). The aim of this study was to determine the local environment of the rare earth in this glass and also to glean information about the effect of glass composition on the rare earth neighbouring (influence of Si, B, Al, Na and Ca contents). To this end, several series of glasses, prepared from the baseline glass, were studied by different characterisation methods such as EXAFS spectroscopy at the neodymium LIII-edge, optical absorption spectroscopy, Raman spectroscopy and {sup 29}Si, {sup 27}Al and {sup 11}B MAS-NMR. By coupling all the results obtained, several hypotheses about the nature of the rare earth neighbouring in the glass were proposed. (author)

  6. Measurement of population inversion obtained in a neodymium-doped glass rod; Mesure de l'inversion de population realisee dans un barreau de verre dope au neodyme

    Energy Technology Data Exchange (ETDEWEB)

    Jego, J.M.; Terneaud, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    After a definition of the yields involved in a laser, measured values of these yields are given and the population inversion in the medium is deduced. (authors) [French] Apres avoir defini les rendements intervenant dans un laser, on donne leurs valeurs mesurees et on en deduit l'inversion de population dans le milieu. (auteurs)

  7. Etude comparative des propriétés thermiques, électriques et optiques des verres du système argent-arsenic-sélénium (United States)

    Sagbo, E.; Houphouet-Boigny, D.; Eholié, R.; Jumas, J. C.; Olivier-Fourcade, J.; Maurin, M.; Rivet, J.


    Thermal, electrical, and optical properties of glass compositions situated along the "As2Se5"-Ag2Se (region I), AsSe-Ag2Se, and AsSe-Ag (region II) lines are investigated and compared. For glass compositions of region I, the glass transition temperature (Tg) and the electrical conductivity (σ) are weak (Tg = 375 ± 5 K and σ = 2,6 × 10-7 cm-1 at 294 K for a 20% concentration of silver). For glass compositions of region II, Tg and σ are higher (Tg = 420 ± 5K and σ = 8,1 × 10-6Ω;-1cm-1 at 298 K for a 20% concentration of silver). All the glasses investigated are high-resistivity and wide-gap semiconductors since their optical gap is higher than 1.4 eV. With increasing Ag content in the glasses, Tg is almost constant, the optical gap decreases slightly but the electrical conductivity increases, and the activation energy decreases.

  8. Ion beam assisted synthesis of nano-crystals in glasses (silver and lead chalcogenides); Synthese assistee par faisceau d'ions d'agregats dans les verres (argent et chalcogenures de plomb)

    Energy Technology Data Exchange (ETDEWEB)

    Espiau de Lamaestre, R


    This work deals with the interest in ion beams for controlling nano-crystals synthesis in glasses. We show two different ways to reach this aim, insisting on importance of redox phenomena induced by the penetration and implantation of ions in glasses. We first show that we can use the great energy density deposited by the ions to tailor reducing conditions, favorable to metallic nano-crystal precipitation. In particular, we show that microscopic mechanism of radiation induced silver precipitation in glasses are analogous to the ones of classical photography. Ion beams can also be used to overcome supersaturation of elements in a given matrix. In this work, we synthesized lead chalcogenide nano-crystals (PbS, PbSe, PbTe) whose optical properties are interesting for telecommunication applications. We demonstrate the influence of complex chalcogenide chemistry in oxide glasses, and its relationship with the observed loss of growth control when nano-crystals are synthesized by sequential implantation of Pb and S in pure silica. As a consequence of this understanding, we demonstrate a novel and controlled synthesis of PbS nano-crystals, consisting in implanting sulfur into a Pb-containing glass, before annealing. Choice of glass composition provides a better control of precipitation physico-chemistry, whereas the use of implantation allows high nano-crystal volume fractions to be reached. Our study of IR emission properties of these nano-crystals shows a very high excitation cross section, and evidence for a 'dark exciton' emitting level. (author)

  9. Contributions of vitreous natural analogs to the investigation of long-term nuclear glass behavior; Apports des analogues naturels vitreux a la validation des codes de prediction du comportement a long terme des verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Techer, I


    This study assesses the extend of the analogy between the alteration behavior in water and in a moist clay environment of aluminosilicate volcanic glass and alumino-borosilicate nuclear containment glass. Basaltic glass alteration in water initially occurs by hydrolysis processes with an activation energy on the order of 73 kJ.mol{sup -1}. As the reaction progresses, the alteration rate drops by over four orders of magnitude from the initial rate r{sub 0}, The alteration kinetics are not governed by the alteration solution chemistry alone, the glass alteration film appears to have a major role as a diffusion barrier limiting the transfer of reaction species and products. All these aspects highlight the behavioral analogy between basaltic glass and nuclear borosilicate glass in aqueous media. Conversely, the alteration reaction of obsidian-type volcanic glass involves other mechanisms than those governing the dissolution of borosilicate glass. Basaltic glass alteration is also examined in the presence of a clay environmental material, in a study of the natural basaltic glass and argillaceous pelites system of the Salagou basin in southern France, in an approach combining mineralogical, chemical and isotopic data to assess the interactions between a basaltic glass and the argillaceous pelites. Laboratory leach test results with basaltic glass and measured data for the Salagou glass in its natural environment are modeled using a code implementing a kinetic law coupling diffusive transfer of dissolved silica with a reaction affinity law. (author)

  10. Importance of space-time fluctuations and non-linearities for the transport inside insulating glasses; Importance des fluctuations spatio-temporelles et des non linearites pour le transport dans les verres isolants

    Energy Technology Data Exchange (ETDEWEB)

    Ladieu, F


    This work deals with transport in insulating glasses. In such solids, the discrete translational symmetry is lost, which means that the plane wave analysis is not a priori the right 'starting point'. As a result, the transport is more difficult to handle, and a huge amount of works have been devoted to many aspects of transport in disordered systems, especially since the seventies. Here we focus on three specific questions: (i) the heat transport in glasses submitted to micro-beams and the associated irreversible vaporization; (ii) the electronic d.c. transport, below 1 Kelvin, in Mott-Anderson insulators, i.e. in 'electron glasses' where both disorder and electron-electron interactions are relevant; (iii) the low frequency dielectric constant in 'structural glasses' (i.e. 'ordinary glasses') which, below 1 Kelvin, is both universal (i.e. independent on the chemical composition) and very different of that of crystals. For each topic, we present both original experiments and the new theoretical concepts that we have elaborated so as to understand the main experimental features. Eventually, it appears that, in any case, transport in insulating glasses is strongly dominated by quite a small part of the 'glass-applied field' ensemble and that the nonlinear response is a relevant tool to get informations on this 'sub-part' which dominates the transport in the whole system. (author)

  11. Contribution to the study of the effects of {alpha}-irradiation in nuclear glasses; Contribution a l'etude des effets de l'irradiation {alpha} sur les verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, A


    The main topic of this work is to characterise the effects of {alpha}-disintegration in nuclear waste glasses. Experimental and numerical approaches have been considered. The structure of the French nuclear waste glass (R7T7) has been simulated using four- and six-oxides simplified glasses which contain the main elements of the R7T7 glass: SiO{sub 2}, B{sub 2}O{sub 3}, Na{sub 2}O, ZrO{sub 2}, Al{sub 2}O{sub 3} and CaO. Four- and six-oxides glasses have been irradiated with 1 MeV-He{sup +} (ionisation) and 2.1 MeV-Kr{sup 3+} (ionisation and atomic collisions) ions in order to reproduce the effects of the {alpha}-particle and of the recoil nucleus emitted during {alpha}-disintegration of actinides, and also to differentiate electronic and ballistic effects. Irradiated glasses have been characterised using several techniques, which have been adapted to the peculiarities of our samples (isolated material, small irradiated depth). The results point out the salient role of sodium in the observed modifications: depth concentration profiles obtained with RBS show an accumulation of sodium at the irradiated surface. We found a apparent acceleration of sodium release in leaching experiments which confirm that point. Modifications observed in Raman spectra of irradiated glasses show an increase of the polymerisation (increase of Q{sub 3}/Q{sub 2} ratio) due to sodium migration. In simplified glasses we have found that the modifications of mechanical properties by external irradiations reproduce the modifications observed in actinide doped nuclear glass (decrease of hardness and increase of fracture toughness). At the same time, we performed Molecular Dynamics simulations of a six-oxides glass. We have shown that the surface modifies the glass structure down to a depth of 10 Angstrom: modification of depth concentration profiles, decrease of the atomic coordination number (A1, B and Si). During cascades, we found that atomic displacements are easier near the surface. This behaviour is also observed when the glass is submitted to an external electric field. In the energy range used, the efficiency of the glassy structure rebuilding seems to be unaffected by the surface. (author)

  12. Influence of clay environment and of corroding canister on the long-term behaviour of nuclear glasses; Influence des materiaux argileux et des produits de corrosion du conteneur metallique sur le comportement a long terme des verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    GIn, St. [CEA Valrho, Dir. de l' Energie Nucleaire, DEN, 30 - Marcoule (France)


    This article reviews the current state of knowledge of R77 glass alteration mechanisms in the presence of the clay materials under consideration for use in an engineered barrier, and in the presence of metal canister corrosion products. These issues are addressed by a phenomenological approach and by modeling. In most cases, the codes are unable to account for the glass alteration data obtained in clay media. The main reason for this discrepancy lies in the glass alteration kinetics (a first-order law based exclusively on silicon) that do not take into account other elements including aluminum, zirconium or the rare earths, which are strongly mobilized in clay media. (author)

  13. Phase separation and crystallization induced by adding molybdenum and phosphorus to soda-lime-silica glasses; Separation de phase et cristallisation induites par l'ajout de molybdene et de phosphore dans un verre silico-sodo-calcique

    Energy Technology Data Exchange (ETDEWEB)

    Cousi, C


    Vitrification of high-level liquid nuclear wastes with high-Mo and P contents causes phase separation and crystallization in silicate matrix. [MoO{sub 4}]{sup 2-} and [PO{sub 4}]{sup 3-} are not bonded to the silicate network and are surrounded by Na{sup +} and Ca{sup 2+} to guarantee their neutrality, involving a recondensation of the vitreous network (Si and P NMR results on SiO{sub 2}-Na{sub 2}O-CaO-MoO{sub 3}-P{sub 2}O{sub 5} glasses). For Mo-rich and P-rich glasses, different crystalline phases appear: Na{sub 2}MoO{sub 4}, Na{sub 2}Mo{sub 2}O{sub 7}, CaMoO{sub 4} and NaCaPO{sub 4}. Quantitative analysis by XRD (Rietveld refinement) has been conducted according to cooling rate and Mo and P contents. Phosphorus addition decreases the crystallization ability of molybdates. The chronology of the phenomena occurring during cooling in these glasses was determined: glass/glass phase separation (1170 deg C), phosphates crystallize at the border of these droplets before molybdates crystallize inside the droplets (920 deg C). (author)

  14. . ﻣﺪة اﻟﺤﻴﺎة ؛ اﻷ ﺎن ﻣ ؛ اﺣﺘﻤﺎل اﻻﻧﻜﺴﺎر ؛ ﺗﺸﺘﺖ اﻟﺨﺼﺎﺋﺺ ا

    African Journals Online (AJOL)

    élasticité pour des corps anisotropes avec application ... Mots clés : stratifié à base de tissus de verre; dispersion de caractéristiques mécaniques; probabilité de rupture; fiabilité; longévité ..... de tissus de verre utilisés pour la fabrication de bateaux.

  15. Micromechanisms of Crack Growth in Ceramics and Glasses in Corrosive Environments. (United States)


    This is a significant difference in behavior between chemical reactions in a pressurized fluid , and reactions at the surface of a stressed solid...Resistance Mecanique du Verre et les Moyens de l’Amelioree, Union Scientifique Continentale du Verre, Charleroix, Belgium, (1962). 8. B. A. Proctor, I

  16. High-Pressure Phases in Shock-induced Melt Veins from the Umbarger L6 Chondrite: Constraints on Shock Conditions (United States)

    Xie, Z.; Tomioka, N.; Sharp, T. G.


    The Umbarger L6 chondrite contains previously unknown high-pressure phases: ringwoodite, akimotoite (MgSiO3-ilmenite), augite, and hollandite phase. Crystallization of akimotoite suggests supercooling of the melt vein during adiabatic decompression.

  17. Author Details

    African Journals Online (AJOL)

    Adil, A. Vol 7, No 2 (2011) - Articles Optimisation du poids de fabrication d'une bouteille de verre creux (CC35) via l'approche Taguchi Abstract PDF · Vol 9, No 3 (2013) - Articles Calcul multi-caractéristique du coût du non-qualité via la fonction Perte de Taguchi (QLF) dans le procédé de fabrication d'un produit de verre ...

  18. Superomniphobic Surfaces for Military Applications: Nano- and Micro-Fabrication Methods. Chapter 2: Investigation of Wear for Superhydrophobic Surfaces and Development of New Coatings (United States)


    revêtement superhydrophobe polyvalent pouvant être appliqué sur des matériaux lisses et rugueux, dans une gamme allant du verre et de l’aluminium au carton...superhydrophobe polyvalent pouvant être appliqué sur des matériaux lisses et rugueux, dans une gamme allant du verre et de l’aluminium au carton et au bois, en

  19. Contribution to the study of the mechanism of crack in amorphous silica: study by the molecular dynamics of crack in amorphous silica; Contribution a l'etude des mecanismes de rupture dans les amorphes: etude par dynamique moleculaire de la rupture de verre de silice

    Energy Technology Data Exchange (ETDEWEB)

    Van Brutzel, L


    The aim of this thesis was to understand the mechanism which occurs during the crack at the atomic scale in amorphous silica. The difficulties of the experimental observations at this length scale lead us to use numerical studies by molecular dynamics to access to the dynamical and the thermodynamical informations. We have carried out large simulations with 500000 atoms and studied the structure of the amorphous silica before to studying their behaviours under an imposed strain. The structure of this simulated amorphous silica settled in three length scales. In small length scale between 0 and 5 angstrom glass is composed of tetrahedra, this is close to the crystalline structure. In intermediate length scale between 3 and 10 angstrom tetrahedra are connected together and build rings of different sizes composed in majority between 5 and 7 tetrahedra. In bigger length scale between 15 and 60 angstrom, areas with high density of rings are surrounded by areas with low density of rings. These structural considerations play an important role in initiation and propagation of a crack. Indeed. in this length scale. crack propagates by growth and coalescence of some small cavities which appear in area with low density of rings behind the crack tip. The cavities dissipate the stress with carries away a delay to propagation of the crack. This phenomenons seems ductile and leads to non linear elastic behaviour near the crack tip. We have also shown that the addition of alkali in the amorphous silica changes the structure by creation of nano-porosities and leads to enhance the ductility during the crack propagation. (author)

  20. Micro-ion beam analysis of physico-chemical reactions in vitro induced by nano-structured sol-gel derived bioactive glasses; Caracterisation par micro-faisceau d'ions des reactions physico-chimiques induites in vitro par des verres bioactifs nanostructures elabores par la methode sol-gel

    Energy Technology Data Exchange (ETDEWEB)

    Lao, J


    The study of bioactive glasses is a multi-field area of research aiming at a major goal: the development of new generation biomaterials that would be able to bond with host tissues through the formation of a strong interfacial bond, together with helping the body heal itself through the stimulation of specific cellular responses. Thus clinical applications of bioactive glasses mainly concern dental surgery and orthopedics, for filling osseous defects. For this purpose, we have elaborated bioactive glasses in the binary SiO{sub 2}-CaO system, ternary SiO{sub 2}-CaO-P{sub 2}O{sub 5} system, and for the first time, to our knowledge, strontium-doped SiO{sub 2}-CaO-SrO and SiO{sub 2}-CaO-P{sub 2}O{sub 5}-SrO glasses. The materials were elaborated using the sol-gel process, which allowed the synthesis of nano-porous materials with great purity and homogeneity. The bio-activity of the glasses was clearly demonstrated in vitro: in contact with biological fluids, the whole lot of mate-rials were able to induce the formation of a Ca-P-Mg layer a few microns thick at their surface. Our work is characterized by the use of PIXE-RBS nuclear microprobes to study the bioactive glass/biological fluids interface. Thanks to these methods we obtained chemical maps that made possible the analysis of major and trace elements concentrations at the interface. Moreover, quantitative information regarding the local reactivity of glasses were acquired. These data are important to evaluate the kinetics and amplitude of the physico-chemical reactions involved in the bio-activity process. Thus, we highlighted that the binary glass is the highest reactive regarding the dissolution of the glassy matrix as well as the first appearance of the Ca-P rich layer. However the Ca/P atomic ratio calculated at the glass/biological fluids interface decreases slowly, indicating that the Ca-P-Mg layer encounters difficulties to be changed into a more stable apatitic phase. For the P-containing glasses, the de-alkalinization of the matrix and the formation of the calcium phosphate layer are delayed. However, calculation of the interfacial Ca/P ratios along with supersaturation studies of the biological medium demonstrate that the Ca-P-Mg layer is quickly changed into an apatitic phase. Concerning the Sr-doped glasses, we highlighted that the dissolution of the material decreased and that the Ca-P-Mg layer was formed on a reduced depth. Nevertheless, according to the rapid decrease of the Ca/P ratio, there is evidence that the layer is more quickly changed into apatite, We also demonstrated that traces of Sr are both present at the glass/biological fluids interface and diffused in the biological medium. Knowing the positive effects of Sr on the cellular activity and on the bone modelling process, it might result in an improved bio-activity for the Sr-doped glasses in contact with a living system. (author)

  1. Irradiations effects on the structure of boro-silicated glasses: long term behaviour of nuclear waste glassy matrices; Effets d'irradiations sur la structure de verres borosilicates - comportement a long terme des matrices vitreuses de stockage des dechets nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Bonfils, J. de


    This work deals with the long term behaviour of R7T7-type nuclear waste glasses and more particularly of non-active boro-silicated glasses made up of 3 or 5 oxides. Radioactivity of active glasses is simulated by multi energies ions implantations which reproduce the same defects. The damages due to the alpha particles are simulated by helium ions implantations and those corresponding to the recoil nucleus are obtained with gold ions ones. Minor actinides, stemming from the used fuel, is simulated by trivalent rare-earths (Eu{sup 3+} and Nd{sup 3+}). In a first part, we have shown by macroscopic experiments (Vickers hardness - swelling) and optical spectroscopies (Raman - ATR-IR) that the structure of the glassy matrices is modified under implantations until a dose of 2,3.10{sup 13}{sup -2}, which corresponds to a R7T7 storage time estimated at 300 years. Beyond this dose, no additional modifications have been observed. The second part concerns the local environment of the rare-earth ions in glasses. Two different environments were found and identified as follows: one is a silicate rich one and the other is attributed to a borate rich one. (author)

  2. Electrical conductivity of oxides from molten state to glassy. Effect on the incorporation of RuO{sub 2} particles; Conductivite electrique des verres et fontes d'oxides. Effets de l'incorporation de particules RuO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Simonnet, C


    This study concerns the electrical conductivity of oxides from molten state to glassy state and, in particular, the effect of the incorporation of RuO{sub 2} particles in the context of vitrification of radioactive waste. The material of interest in the nuclear field is basically a viscous or vitreous borosilicate containing a dispersion of RuO{sub 2} microcrystals. A very simple model of this heterogeneous material has been studied in particular (SiO{sub 2}, B{sub 2}O{sub 3}, Na{sub 2}O, RuO{sub 2}). An original method of impedance measurement in the liquid at high temperature yields reliable electrical conductivity values over a temperature range covering the liquid and vitreous phases of the borosilicates studied. In the borosilicate matrix, alkaline transport is mainly responsible for the ionic conduction. The temperature dependence of the conductivity may thus be represented by an equation combining a VFT law and an Arrhenius law to represent the electrical conductivity above and below T{sub g}. Beyond a critical volume fraction V{sub c} {approx} 0.01 of RuO{sub 2}, an electronic contribution is added to the ionic contribution of the matrix and the electrical conductivity increases significantly with the RuO{sub 2} content. This effect is described in terms of electrical percolation of the particle network. An electronic mechanism by tunnel transfer between particles is demonstrated. A mathematical model is developed to describe this mechanism in the solid composite. Beyond T{sub g}, conduction by the tunnel effect persists and the partial solubilization of RuO{sub 2} appears to be mainly responsible for the significant increase in electronic conductivity with the temperature. (author)

  3. Partitioning of the rare earths and actinides between R7T7 nuclear glass alteration products and solution according to disposal conditions; Partage des terres rares et des actinides entre solution et produits d`alteration du verre nucleaire type R7T7 en fonction des conditions de stockage

    Energy Technology Data Exchange (ETDEWEB)

    Menard, O.


    The alteration of nuclear glass by water is liable to release radionuclides into the environment. Determining the release kinetics of these elements and their aqueous chemical forms are therefore essential steps in establishing the safety of a geological repository site. Leach tests were conducted with a nonradioactive specimen of the French ``R7T7`` light water containment glass spiked with U and Th, and with two R7T7 specimens spiked with {sup 237}Np and {sup 239}Pu, respectively. The alteration solution compositions were representative of deep groundwater and contained carbonate, sulfate, phosphate, fluorine and chlorine ions. The release of U, Th, Np and Pu, as well as of the rare earths La, Ce and Nd were monitored by ICP mass spectrometry and by {alpha} spectrometry. Scanning and transmission electron microscopic examination of the nonradioactive altered glass surfaces was also performed to assess the partitioning balance for the rare earths, U and Th between the glass alteration products and solution. The mobility of these elements depends on two competing mechanisms. The rare earths and thorium are incorporated in the alteration products (gel); the retention process is assumed to involve chemisorption or coprecipitation, enhanced in the gel layer by the presence of phosphate ions in particular. Conversely, the aqueous species in the alteration solutions (mainly anions) form complexes with the actinides and rare earths; this phenomenon is particularly evident with U and Np. The presence of carbonate ions favors this mobility. Plutonium differs from U and Np in that it is adsorbed mainly on colloids formed by glass dissolution, the principal factors governing its chemical evolution in solution. (author). refs., 122 figs., 185 tabs.

  4. Chemical durability and resistance to irradiation of LnYSiAlO (Ln=La or Ce) glasses, potential immobilization matrix of minor actinides; Durabilite chimique et comportement a l'irradiation des verres quaternaires LnYSiAlO (Ln = La ou Ce), matrice potentielle d'immobilisation d'actinides mineurs trivalents

    Energy Technology Data Exchange (ETDEWEB)

    Gavarini, St


    Rare earth aluminosilicate glasses are known for their interesting mechanical and optical properties. Recent studies have shown that their chemical durability was very good too, such they have the potential to be used in the nuclear industry for the specific immobilization of trivalent actinides. Initial dissolution rates of LaYSiAlO and CeYSiAlO were determined using a Soxhlet device (dynamic leaching). The differences linked to the nature of the rare earth element were studied by synthesizing analogous glasses that only differed in their rare earth element composition (%at.): Y-5%, La-5 %, Si-15%, Al-10% O-65%. The influence of pH on the dissolution mechanisms and kinetics was also studied by static leaching tests performed in dilute solutions of NaOH or HNO{sub 3}. Electronic defects and collision cascades, induced by a-disintegration of radioelements confined in storage matrix, can cause important modifications in the glass structure and, thus, influence its chemical durability. To simulate these effects, glass samples were irradiated with {beta} particles and heavy ions accelerated to 2,5 MeV and 200 keV, respectively. Monoliths were then leached in static bi-distilled water (pH{>=}{>=} 5.5) for one month in an autoclave heated to 90 degrees C. Initially, the structural changes caused by irradiation were determined using Raman, NMR and EPR spectroscopies. Ion {mu}-beams, SEM-EDS and XPS analysis were also performed to evaluate the potential modifications of the superficial composition. Finally, the leaching behavior was studied, for both irradiated and unirradiated samples, through solution and solid elementary characterization. (author)

  5. Wastes vitrification by plasma torch: study of a glass formulation compatible with a wide range of B wastes; Vitrification des dechets par torche a plasma: recherche d'une formulation de verre compatible avec un large eventail de dechets B

    Energy Technology Data Exchange (ETDEWEB)

    Poitou, S.; Richaud, D.; Fiquet, O.; Gramondi, P.; Massit, H. [CEA Cadarache, Dept. d' Entreposage et de Stockage des Dechets, 13 - Saint-Paul-lez-Durance (France)


    Within the context of radioactive waste management, CEA has equipped itself with a 'PLASMARC' device. The central element of this device is a plasma torch treatment furnace. It has been implemented and validated for the vitrification of low level radioactive wastes. Meanwhile, the plasma torch presents potentially interests for immobilizing under an inert form in vitreous matrices, B wastes which are generally divided and of complex chemical composition. The application of this process to this type of wastes has been studied here. The obtained results show that with the plasma torch it is possible to make glasses with a high amount of silicon and aluminium oxide and which are adapted to the treatment / packaging of the B wastes. (O.M.)

  6. Structure study and properties of rare earth-rich glassed for the conditioning of nuclear waste; Etude des caracteristiques structurales et des proprietes de verres riches en terres rares destines au confinement des produits de fission et elements a vie longue

    Energy Technology Data Exchange (ETDEWEB)

    Bardez, I


    A new nuclear glass composition, able to immobilize highly radioactive liquid wastes from high burn-up UO{sub 2} fuel, was established and its structure studied. The composition of the selected rare earth-rich glass is (molar %): 61.79 SiO{sub 2} - 8.94 B{sub 2}O{sub 3} - 3.05 Al{sub 2}O{sub 3} - 14.41 Na{sub 2}O - 6.32 CaO - 1.89 ZrO{sub 2} - 3.60 RE{sub 2}O{sub 3} (with RE = La, Ce, Pr and Nd) The aim of this study was to determine the local environment of the rare earth in this glass and also to glean information about the effect of glass composition on the rare earth neighbouring (influence of Si, B, Al, Na and Ca contents). To this end, several series of glasses, prepared from the baseline glass, were studied by different characterisation methods such as EXAFS spectroscopy at the neodymium L{sub III}-edge, optical absorption spectroscopy, Raman spectroscopy and {sup 29}Si, {sup 27}Al and {sup 11}B MAS-NMR. By coupling all the results obtained, several hypotheses about the nature of the rare earth neighbouring in the glass were proposed. (author)

  7. Methods for the preparation of ultra-pure anhydrous zirconium tetrafluoride from zirconium tetraborohydride, researches in connection with halide glasses; Methodes d`obtention du tetrafluorure de zirconium ultra pur anhydre a partir du tetraborohydrure de zirconium, recherches liees aux verres de fluorures

    Energy Technology Data Exchange (ETDEWEB)

    Tortevois, R.


    The synthesis of ultrapure zirconium tetrafluoride, the main component of fluorozirconate based optical fibers, was successfully attempted from zirconium tetraborohydride. Of the fluorinating agents used, nitrogen trifluoride doesn`t react with zirconium tetraborohydride while xenon difluoride reacts too violently and leads to phases which contain boron. The fluorination in a compatible solvent enabled us to minimize the degradation. The best results were obtained with the fluorination of Zr(BH{sub 4}){sub 4} dissolved in CFCl{sub 3} at -40 deg C by anhydrous HF. Using several analytical methods such as graphite furnace atomic absorption and proton activation, we analyzed the purity. The degree of transition element impurities is less than the ppm level for ZrF{sub 4}. The dehydration of ZrF{sub 4},H{sub 2}O and ZrF{sub 4},3H{sub 2}O at room temperature by CIF{sub 3} in gaseous and liquid state was also investigated. At exceptionally low temperature, this process allows oxide and oxyfluoride components to be reduced.

  8. R7T7 glass alteration mechanism in an aqueous closed system: understanding and modelling the long term alteration kinetic; Etude des mecanismes d'alteration par l'eau du verre R7T7 en milieu confine: comprehension et modelisation de la cinetique residuelle

    Energy Technology Data Exchange (ETDEWEB)

    Chave, T


    The long term alteration rate of the French R7T7 nuclear glass has been investigated since many years because it will define the overall resistance of the radionuclide containment matrix. Recent studies have shown that the final rate remains constant or is slightly decreasing with time. It never reaches zero. Though this residual rate is very low, only 5 nm per year at 50 C, it would be the dominant alteration phenomenon in a geological repository. Two mechanisms are suggested for explaining such behaviour: diffusion in solution of elements from glass through an amorphous altered layer and precipitation of neo-formed phases. The diffusion processes are in agreement with a solid state diffusion mechanism and can lead to secondary phase precipitation due to solution concentration increases. Observed phases are mainly phyllosilicates and zeolites, in specific conditions. Phyllosilicates are expected to maintain the residual kinetic rate whereas alteration resumption could be observed in presence of zeolites at very high pH or temperature (10.5 at 90 C or temperature above 150 C). Both diffusion and neo-formed phase precipitation have been investigated in order to better understand their impact on the residual alteration rate and have then been modelled by a calculation code, coupling chemistry and transport, in order to be able to better anticipate the long term behaviour of the glass R7T7 in an aqueous closed system. (author)

  9. The understanding of the R7T7 glass blocks long term behavior: chemical and transport coupling in fractured media; Comprehension de l'alteration a long terme des colis de verre R7T7: etude du couplage chimie transport dans un milieu fissure

    Energy Technology Data Exchange (ETDEWEB)

    Chomat, L


    The long term behavior of nuclear waste glass blocks depends highly on chemical reactions which occur at the surface in contact with water. Studies carried out on inactive fractured glass blocks show that fracture networks play a significant part in reactive surface area. Nevertheless, the complexity of results interpretation, due to a weak knowledge of fracture networks and local lixiviation conditions, does not allow us to comprehend the physical and chemical mechanisms involved. Model cracks are a key step to study chemical and transport coupling in fractured media. Crack lixiviation in aggressive conditions (pH{>=}11) show that the crack's position (horizontal or vertical) determines the dominant transport mechanism (respectively diffusion or convection induced by gravity). This gravity driven flow seems to be negligible in lower pH conditions. The convective velocity is estimated by a 1D model of reactive transport. Two other parameters are studied: the influence of thermal gradient and the influence of interconnected cracks on alteration. A strong retroactive effect of convection, due to thermal gradient, on the alteration kinetic is observed inside the crack. These works lead to a complete alteration experiment of a 163 crack network subject to a thermal gradient. The use of the geochemical software, HYTEC, within the framework of this study shows the potential of the software which is however limited by the kinetics law used. (author)

  10. Alteration of 'R7T7' type nuclear glasses: statistical approach, experimental validation, local evolution model; Alteration des verres nucleaires de type 'R7T7': demarche statistique, validation experimentale, modele local d'evolution

    Energy Technology Data Exchange (ETDEWEB)

    Thierry, F


    The aim of this work is to propose an evolution of nuclear (R7T7-type) glass alteration modeling. The first part of this thesis is about development and validation of the 'r(t)' model. This model which predicts the decrease of alteration rates in confined conditions is based upon a coupling between a first-order dissolution law and a diffusion barrier effect of the alteration gel layer. The values and the uncertainties regarding the main adjustable parameters of the model ({alpha}, Dg and C*) have been determined from a systematic study of the available experimental data. A program called INVERSION has been written for this purpose. This work lead to characterize the validity domain of the 'r(t)' model and to parametrize it. Validation experiments have been undertaken, confirming the validity of the parametrization over 200 days. A new model is proposed in the second part of this thesis. It is based on an inhibition of glass dissolution reaction by silicon coupled with a local description of silicon retention in the alteration gel layer. This model predicts the evolutions of boron and silicon concentrations in solution as well as the concentrations and retention profiles in the gel layer. These predictions have been compared to measurements of retention profiles by the secondary ion mass spectrometry (SIMS) method. The model has been validated on fractions of gel layer which reactivity present low or moderate disparities. (author)

  11. Shock-induced transformations in the system NaAlSiO4-SiO2 - A new interpretation (United States)

    Sekine, Toshimori; Ahrens, Thomas J.


    New internally consistent interpretations of the phases represented by the high pressure phase shock wave data for an albite-rich rock, jadeite, and nepheline in the system NaAlSiO4-SiO2, are obtained using the results of static high pressure investigations, and the recent discovery of the hollandite phase in a shocked meteorite. We conclude that nepheline transforms directly to the calcium ferrite structure, whereas albite transforms possibly to the hollandite structure. Shock Hugoniots for the other plagioclase and alkali feldspars also indicate that these transform to hollandite structures. The pressure-volume data at high pressure could alternatively represent the compression of an amorphous phase. Moreover, the shock Hugoniot data are expected to reflect the properties of the melt above shock stresses of 60-80 GPa. The third order Birch-Murnaghan equation of state parameters are given for the calcium ferrite type NaAlSiO4 and for albite-rich, orthoclase-rich, and anorthite-rich hollandites.

  12. Preparation of α-MnO 2with an Open Tunnel (United States)

    Muraoka, Yuji; Chiba, Hiroshi; Atou, Toshiyuki; Kikuchi, Masae; Hiraga, Kenji; Syono, Yasuhiko; Sugiyama, Shoko; Yamamoto, Sadaaki; Grenier, Jean-Claude


    A single-phaseα-MnO2without any large stabilizing cations was successfully prepared by starting from hollandite-type (NH4)xMn8O16and quenching from 440°C during heating in flowing Ar. The unit-cell dimension was determined by XRD analysis to bea=10.308(2) Å andc=2.854(1) Å. In comparison with that of the starting material (a=9.896(1) Å andc= 2.859(1) Å), theadimension increased while thecdimension changed little. No presence of ammonium ions in the structure of this specimen was shown by IR spectroscopy, the Kjeldahl analysis, or temperature-programmed-desorption (TPD) measurement. The structural change from the hollandite phase to Mn2O3was observed at 540°C. TPD analysis indicates the presence of nitrogen other than ammonium ions in the hollandite material we prepared, and also suggests that this nitrogen might have a strong chemical interaction to the hollandite structure.

  13. Wideband Detection and Classification of Practice Limpet Mines against Various Backgrounds (United States)


    d’étalonnage de RDDC Atlantique à l’aide d’une perche rotative. Deux disques ont été examinés : un en aluminium et l’autre, en fibre de verre . Les...fibre de verre . Dans le présent rapport, nous examinons certaines mines ventouses réelles d’entraînement placées sur deux disques de référence, que...l’aide d’une perche rotative. Deux disques ont été examinés : un en aluminium et l’autre, en fibre de verre . Les disques ont été tournés au-dessous d’un

  14. Wideband Detection and Classification of Mines in a Simulated ship Hull Scenario (United States)


    caoutchouc et de billes d’acier, sur une feuille de fibre de verre, par la suite suspendue dans le bassin d’étalonnage acoustique de RDDC Atlantique...expérience avait pour but d’établir la facilité avec laquelle on pouvait distinguer la « mine » attachée dans l’écho réfléchi par la feuille de fibre de...d’acier, sur une feuille de fibre de verre, par la suite suspendue dans le bassin d’étalonnage acoustique de RDDC Atlantique. Ce montage a été ensuite

  15. Observations on the Characteristics of the Exchange Flow in the Daranelles Strait (United States)


    cm/s) uerr b (cm/s) umax (cm/s) umin (cm/s) vmean (cm/s) vstd (cm/s) verr b (cm/s) vmax (cm/s) vmin (cm/s) M1/7.1 53.9 26.4 5.1 74.7 109.5 3.7 6.5...errors of velocity means (uerr, verr ), maximum (umax, vmax), and minimum (umin, vmin) values of the along- (u) and across-strait (v) velocity components

  16. Synthetic Aperture Processing of Wideband Scattering Measurements Made in the DRDC Atlantic Acoustic Calibration Tank (United States)


    Atlantique à l’aide d’une perche rotative. Deux disques ont été examinés : un en aluminium et l’autre en fibre de verre . Ces disques ont été tournés...Atlantique à l’aide d’une perche rotative. Deux disques ont été examinés : un en aluminium et l’autre en fibre de verre . Ces disques ont été tournés sous

  17. Current Flow Through Two Dimensional Arrays of Metal Nanoparticles as a Novel Sensor Platform (United States)


    sur du graphite pyrolytique de qualité élevée, du verre et des substrats de polyéthylène, formaient de tels films. L’implantation de 2-CEES é l’environnement du soldat. On a récemment expérimenté pour mieux résoudre ce problème en déposant des nanoparticules de métal sur du verre et

  18. Caractérisation de la rétrodiffusion Brillouin dans une fibre optique chalcogénure AS42S58 microstructurée


    Tchahame, J.C.; Beugnot, J-C; Brilland, L; Méchin, D; Troles, J; Maillotte, H; Sylvestre, T


    International audience; Dans ce document, nous présentons les résultats de caractérisation de la rétrodiffusion Brillouin dans une fibre optique microstructurée (FOM) en verre de chalcogénure As 42 S 58 . Les résultats obtenus montrent que cette fibre optique serait appropriée pour des applications en optique non-linéaire basées sur l'effet Brillouin. MOTS-CLEFS : Effet Brillouin ; verres chalcogénures ; fibres optiques microstructurées.

  19. Helicopter Fatigue. A Review of Current Requirements and Substantiation Procedures (United States)


    serait int~ressant de voir si ellas peuvent Ztre exploit~es dans notre optique . De toute fagon, la somme de travail restante et las d6iais n~cessaires...Gazelle en fibres de verre et r~sine qui totalisent 1 500 000 heures de vol sans probl~me maje-ur. Compar~es aux pales m6talliques, elles permettent...aliser des moyeux a partir de tissus et de fibres unidirectionnelles de verre impr6gn~s de r~sine 6poxyde. Cette construction nous a procure l’avantage

  20. De impact van de ziekte van Addison, AGS of het syndroom van Cushing op het dagelijks leven en de zorg: een onderzoek vanuit patiëntenperspectief.

    NARCIS (Netherlands)

    Heijmans, M.J.W.M.; Rijken, M.


    Negentig procent van de mensen met de ziekte van Addison, de ziekte van Cushing of het Adrenogenotaalsyndroom (AGS) is altijd moe. Dit is ruim tweemaal zoveel als in de algemene bevolking. Hoewel hun aandoening in medisch opzicht ‘onder controle’ is, is de kwaliteit van hun leven vaak verre van

  1. n groot letterkundige en geesverwant gesê: ,,De wereld blijft niet ...

    African Journals Online (AJOL)


    In hoe- verre hierdie boek sal inslaan en invloed sal uitoefen, moet die tyd ons nog leer. Nadat ons nou hierdie paar lyne getrek het, kan ons daarbo die veel- aangehaalde gedig van TENNYSON as paslike opskrif sit:—. „Flower in the crannied wall,. I pluck you out of the crannies;. I hold you here, root and all, in my hand,.


    African Journals Online (AJOL)

    Afrikaner koeie en verre binnc die oerste 3 weke vur die toeheiroen gcdek is en 95%Uinne ncge weke. Slcgr 67gohet draglig geraek. Nogatbrre korrelasies ven omgowingstemporttuur met die aantal ruksrvolle dekkbrys en beretting hct getoon det'n noue omgekeorde verwantshsp tulsGn ho€ tempcrature (> 30o) en die ...

  3. Translational Aspects of Behçet’s Disease : Genetics, cytokines and new treatment modalities

    NARCIS (Netherlands)

    J.H. Kappen (Jasper)


    markdownabstract__abstract__ De ziekte van Behçet is een multi-factoriele (auto)inflammatoire vascilitis die vooral voorkomt bij mensen uit landen van de Middellandse Zee gebied en langs de voormalige zijderoute naar het Verre Oosten, er zijn ongeveer 600 patiënten in Nederland. Algemeen wordt

  4. Identification of Flaws Responsible for Crack Initiation and Micromechanisms of Slow Crack Growth in the Delayed Fracture of Alumina. (United States)


    application of very high loads. Another apparatus to be considered area pressurized fluid layer between the matinq 72 73 surfaces and an air bearing as...R.J. Charles and W.B. Hillig, "Kinetics of Glass Failure of Stress Corrosion," Symposium sur la Resistance Mecanique du Verre et les Moyens de

  5. Author Details

    African Journals Online (AJOL)

    Assarar, M. Vol 24 (2015) - Articles Impact de la fatigue et du vieillissement hygrothermique en eau douce sur un composite unidirectionnel verre-époxy. Abstract PDF. ISSN: 2352-9717. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  6. Impact de la fatigue et du vieillissement hygrothermique en eau ...

    African Journals Online (AJOL)

    Impact de la fatigue et du vieillissement hygrothermique en eau douce sur un composite unidirectionnel verre-époxy. Younès Menail1, Bachir Redjel2, Abderrahim El Mahi3 & Mustapha Assarar4. 1LR3MI, Université Badji Mokhtar, BP 12, Annaba. 2 Laboratoire de Génie civil, Université Badji Mokhtar, BP 12, Annaba.

  7. Synthèse: Revue des Sciences et de la Technologie - Vol 24 (2015)

    African Journals Online (AJOL)

    Impact de la fatigue et du vieillissement hygrothermique en eau douce sur un composite unidirectionnel verre-époxy · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Y Menail, B Redjel, A El Mahi, M Assarar, 38-43 ...

  8. Nazis in the Netherlands: A social history of National Socialist collaborators, 1940-1945

    NARCIS (Netherlands)

    Damsma, J.M.


    ‘NSB’er’ is nog steeds een populair scheldwoord. De persoon in kwestie is lafhartig, in staat tot verraad, of in ieder geval iemand van wie je je verre moet houden als het erop aankomt in oorlogstijd. Dit beeld is grotendeels gebaseerd op de keuzes en daden van NSB’ers ten tijde van de Tweede

  9. Redaksioneel

    Directory of Open Access Journals (Sweden)

    Fika J. van Rensburg


    Full Text Available Toe ek die oproep uitgestuur het om bydraes vir hierdie Festschrift te vra, het kollegas van heinde en verre positief gereageer – ’n teken van die hoë agting, respek en waardering vir Tjaart van der Walt, ’n “slaaf van Christus” onder ’n wye kring navorsers!

  10. Propriétés structurales, optiques et électriques des couches minces ...

    African Journals Online (AJOL)

    Des couches minces de TiO2 dope au cuivre ont ete preparees par la methode Sol-Gel et deposees selon le procede dip-coating sur des substrats en verre. Les proprietes structurales, optiques et electriques des echantillons monocouches dopes 0, 3 et 7 % at. cuivre ont ete analysees par diffraction des ...

  11. Richard Poynder: lo stato dell’accesso aperto

    Directory of Open Access Journals (Sweden)

    Maria Chiara Pievatolo


    Full Text Available “La storia dell’accesso aperto, quando verrà scritta, narrerà la vicenda di un gruppo di spiriti nobili che, contro l’aspra resistenza degli editori, hanno demolito le barriere economiche attorno alla ricerca a finanziamento pubblico? O riferirà di come un’industria editoriale altamente...

  12. Tomáš Sedláček: l’economia del bene e del male

    Directory of Open Access Journals (Sweden)

    Maria Chiara Pievatolo


    Full Text Available Un sabato fatto per l’uomo Alla fine di ogni settennio concederai la remissione. Questa è la regola della remissione: ogni creditore rimetterà ciò che verrà prestato al suo prossimo; non costringerà al pagamento né il suo prossimo né il suo...

  13. Schouderarthrodese

    NARCIS (Netherlands)

    Fontijne, Willem


    SAMENVATTING Het na-onderzoek van een aantal patienten bij wie een schouderarthrodese was gedaan leerde dat de beweging van de arm in abductie verre ten achter bleef bij die in anteflexie, waarbij de stand der arthrodese een ankylose in grotere abductie dan in anteflexie werd nagestreefd en

  14. Crystallization behavior during melt-processing of ceramic waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Tumurugoti, Priyatham; Sundaram, S.K.; Misture, Scott T. [Kazuo Inamori School of Engineering, The New York State College of Ceramics, Alfred University, Alfred, NY, 14802 (United States); Marra, James C. [Savannah River National Laboratory, Aiken, SC, 29808 (United States); Amoroso, Jake, E-mail: [Savannah River National Laboratory, Aiken, SC, 29808 (United States)


    Multiphase ceramic waste forms based on natural mineral analogs are of great interest for their high chemical durability, radiation resistance, and thermodynamic stability. Melt-processed ceramic waste forms that leverage existing melter technologies will broaden the available disposal options for high-level nuclear waste. This work reports on the crystallization behavior in selected melt-processed ceramics for waste immobilization. The phase assemblage and evolution of hollandite, zirconolite, pyrochlore, and perovskite type structures during melt processing were studied using thermal analysis, x-ray diffraction, and electron microscopy. Samples prepared by melting followed by annealing and quenching were analyzed to determine and measure the progression of the phase assemblage. Samples were melted at 1500 °C and heat-treated at crystallization temperatures of 1285 °C and 1325 °C corresponding to exothermic events identified from differential scanning calorimetry measurements. Results indicate that the selected multiphase composition partially melts at 1500 °C with hollandite coexisting as crystalline phase. Perovskite and zirconolite phases crystallized from the residual melt at temperatures below 1350 °C. Depending on their respective thermal histories, different quenched samples were found to have different phase assemblages including phases such as perovskite, zirconolite and TiO{sub 2.} - Highlights: • Crystallization behavior during melt processing multiphase ceramics was studied. • Phase evolution order upon cooling was hollandite → perovskite → zirconolite → TiO{sub 2}. • Hollandite phases co-exists with a liquid phase at temperatures >1500 °C. • Zirconolite crystallization is complex and involves intermediate phases.

  15. Das Labor als Ort des Schreckens - Zur Repräsentation des Wissenschaftlers im Film

    Directory of Open Access Journals (Sweden)

    Karin Kaltenbrunner


    Full Text Available Die Wirkungsstätte der Wissenschaft ist im Film zumeist ein Ort des Grauens, ein Raum voller geheimnisvoller Flüssigkeiten, seltsamer Apparaturen und konservierter Körperteile, in dem ein verrückter Wissenschaftler perfide Experimente durchführt. Karin Kaltenbrunner geht dieser Überlappung von inszenierter Wissenschaft und Filmgeschichte anhand verschiedener Verfilmungen von Mary Shelleys "Frankenstein" nach. Die Wirkungsstätte der Wissenschaft ist im Film zumeist ein Ort des Grauens, ein Raum voller geheimnisvoller Flüssigkeiten, seltsamer Apparaturen und konservierter Körperteile, in dem ein verrückter Wissenschaftler perfide Experimente durchführt. In diesem Bild verbinden sich archaische Erzähltraditionen mit aktuellen Tendenzen der Forschung.

  16. Un cas particulier de la relation partie-tout: les compléments adnominaux en à avec et sans article défini anaphorique

    Directory of Open Access Journals (Sweden)

    Vassil Mostrov


    Full Text Available This paper deals with the syntax and the interpretation of French noun phrases of the type N à N where a part-whole relationship is involved. We focus on the differences arising from the presence (un verre au pied doré/cassé or absence of a determiner (un verre à pied [doré] before the N denoting the part. We argue that both the adnominal complements à N (Mod and à LE N Mod function as adjectival constituents that qualify the noun denoting the whole, but the actualization of the part noun can be linguistically effective only in cases where the definite determiner, A-bound according to Guéron’s (1985, 2005 hypothesis, is present. The discussion considers the consequences of our analysis.

  17. A hardware field simulator for photovoltaic materials applications.


    Massi Pavan, Alessandro


    2006/2007 Il presente lavoro riguarda la descrizione di un simulatore di campo fotovoltaico (in seguito simulatore). Il simulatore è un convertitore elettronico di potenza che, alimentato dalla rete elettrica, riproduce la caratteristica tensione corrente di un campo fotovoltaico (insieme di moduli fotovoltaici connessi in serie e in parallelo) operante in condizioni climatiche di temperatura e irraggiamento arbitrarie. Il nuovo dispositivo verrà impiegato nell’ambito del laborato...

  18. La largeur de bande pourrait permettre aux universités africaines de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2 févr. 2011 ... La largeur de bande idéale pour les universités utilise un câble à fibres optiques ─ c'est rapide, relativement peu coûteux et offre un grand débit. (Les câbles à fibres optiques utilisent de minces fibres de verre pour transmettre de grandes quantités de données sous forme d'impulsions lumineuses.) ...

  19. International Conference on Electromagnetic Windows (4th). (United States)


    Structure -Radioelectricite) for calculating in-flight radome effects. It is composed of 3 separate, independent parts, simulating respectively thermal... structural , and EM parameters. Experimental verification included measure- ment of a silicon-glass radome at Mach 6 in a wind tunnel and its EM measure...Diglectriques d’un StratifiA Verre-Rgsine PSP. (Di- clectric Property of Stratified Glass-Resin Poly[styrylpyridine]). (J. Touraine, Electronique Marcel

  20. Browse Title Index

    African Journals Online (AJOL)

    Vol 2, No 2 (2006), Caractérisation du comportement mécanique d'un composite (tissu de verre/résine époxyde) à différentes périodes de vieillissement hygrothermiques, Abstract PDF. A Naceri, A Vautrin. Vol 9, No 2 (2013), Caractérisation du matériau bois de structures utilisé en construction par la méthode vibratoire ...

  1. Inventaire et caractérisation des plantes médicinales utilisées en ...

    African Journals Online (AJOL)


    31 oct. 2016 ... pour l'alimentation, les soins, l'énergie, l'habillement et la construction des ... Les différents systèmes de soins mis en place, ont fait ..... Feuilles 3,19 Plaies. Panaris. Stérilité. Friction. Ecraser. Décoction. Déposer sur la plaie jusqu'à arrêt des saignements. Répartir autour de la partie atteinte. 1verre M et S ...

  2. Comportement expérimental aux cisaillements roulant et de voile de ...

    African Journals Online (AJOL)

    comme étant la conséquence de l'augmentation du taux d'humidité. Ils notent une solide corrélation ... de gonflement et ses conséquences négatives sur les performances mécaniques de l'OSB, ainsi que les ...... Impact de la fatigue et du vieillissement hygrothermique en eau douce sur un composite unidirectionnel verre-.

  3. Advanced Non-Intrusive Instrumentation for Propulsion Engines (United States)


    decouplage entre les reflexions parasites du rayonnement excitateur et la fluorescence est realise facilement au moyen d’un filtre en verre colore. Des ...l’expression du signal de fluorescence normalise par la puissance laser mesuree localement se resume ä une expression ä une seule variable, la...frequence d’emission et d’un Systeme de calagc et de pilotage en frequence dit Autoscan. En utilisant comme milieu actif le colorant Pyromethene 556

  4. Optimisation de la fermentation en milieu semi-solide pour la ...

    African Journals Online (AJOL)

    ... aucun effet significatif (P>0,05) du matériel de fermentation n'a été mis en évidence sur les paramètres mesurés. Le taux de levure, la température et la durée de fermentation avaient une influence positive significative (P<0,05) sur la quantité de mousse produite. Conclusion et application : Le dispositif en verre, suivi de ...

  5. Déchets solides encombrants les plages d'Annaba | Chaouch ...

    African Journals Online (AJOL)

    Les rejets des déchets solides sur nos plages constituent une véritable plaie qui dégrade la beauté des paysages. Pour cela, nous avons identifié et quantifié les détritus solides d'origine urbaine encombrant les plages du littoral d'Annaba. Nos résultats montrent que les verres et les métaux viennent en 1ère position avec ...

  6. Importance ethnobotanique et valeur d'usage de Picralima nitida ...

    African Journals Online (AJOL)

    Aux personnes souffrantes de l'angine et toutes autres douleurs de la gorge. -. Analgésique,. Stimulant. Décoction d'écorce de racine ou des graines séchées réduit en poudre. Un verre bambou une fois par jour jusqu'à la disparition de la douleur. Contre la jaunisse, les vers intestinaux et surtout l'ulcère gastrique. -. Contre.

  7. African Journal of Neurological Sciences - 2009 Vol. 28 No 1

    African Journals Online (AJOL)

    L'interrogatoire ne rapporte pas de trouble de la vigilance, de crise épileptique ni de signes d'hypertension intracrânienne. Ailleurs il présente dans ses antécédents une intoxication alcoolique chronique depuis plus de 30ans (alcool traditionnel, bières locales, vin et liqueur) à raison de 3 à 4 verres de. 40 ml de liqueur par ...

  8. Guided Optical Structures in the Military Environment (United States)


    Stanford University, 26A--1 VERRES FLUORES POUR GUIDES DIONDE INFRA ROUGE. J. Lucas, Professeur Laboratoire de Chimie Nlindrale D, Campus de matriraux oxistont A lista& vitroux at a fortiori des matdrisux ay Ant une large bande do transparence. L# chimie des vorros est largement dominde...toutolois remarquor quo beaucoup do matdriaux, dont Is tlsau humain,l ont peu absorbants ft cette longuour d’onde. Los matE- riaux organiques , on inclut idi

  9. Impact de la fatigue et du vieillissement hygrothermique en eau ...

    African Journals Online (AJOL)

    Le présent article contribue à mettre en relief l'impact de la fatigue en traction et du vieillissement naturel en eau douce sur deux composites, verre époxy. Deux séries d'essais ont été mises en place pour distinguer les effets de la fatigue et ceux du vieillissement hygrothermique. Durant la première série, nous avons gardé ...

  10. Author Details

    African Journals Online (AJOL)

    Vautrin, A. Vol 2, No 2 (2006) - Articles Caractérisation du comportement mécanique d'un composite (tissu de verre/résine époxyde) à différentes périodes de vieillissement hygrothermiques. Abstract PDF. ISSN: 1813-548X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

  11. Author Details

    African Journals Online (AJOL)

    Naceri, A. Vol 2, No 2 (2006) - Articles Caractérisation du comportement mécanique d'un composite (tissu de verre/résine époxyde) à différentes périodes de vieillissement hygrothermiques. Abstract PDF. ISSN: 1813-548X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

  12. Etude des potentialites germinatives pour une regeneration ...

    African Journals Online (AJOL)

    Les différents aspects germinatifs du fruit de Neocarya macrophylla, ressource génétique fruitière spontanée du Niger, ont fait l'objet d'analyses. L'étude des performances germinatives de cette espèce a donc porté sur des graines récentes et des graines conservées à la température ambiante dans des flacons en verre ...

  13. Procédé de l'étude de la rupture des fibres à partir d'un essai en ...

    African Journals Online (AJOL)

    Le travail consiste à solliciter en traction des mèches de fibres de verre, en utilisant l'émission acoustique pour suivre en temps réel l'endommagement du matériau. En effet, les ruptures de fibres s'accompagnent de libération d'énergie sous formes d'ondes acoustiques, qui sont localisés et analysés ensuite. Les objectifs ...

  14. breeding of sweetpotato and evaluation of imported cultivars in ...

    African Journals Online (AJOL)

    Le virus testé de collection de la maison en verre de 263 accessions locales et 52importées sert de base au programme. Les activités de reproduction àRoodplaat consistent aussi à l'importation des germplasmes originaux, au multi croisements (5309 graines), à la sélection rigoureuse de 3116 semis dans le jardin des ...

  15. Un champ de cratères d'impact au sommet du Nkol Nyara à Leboudi ...

    African Journals Online (AJOL)

    L'importance des fontes représentées par une couche et des veinules de verre de couleur noire recouvrant ou affectant des gneiss clairs à grenat et disthène la roche trame hébergeant ces cratères, rend compte d'un processus thermique lié à l'arrivée au sommet du Nkol Nyara, d'un essaim ou d'une pluie de minuscules ...

  16. Valorisation des plantes médicinales à coumarines des marchés de ...

    African Journals Online (AJOL)


    30 janv. 2015 ... Mpondo et al.. J. Appl. Biosci. Valorisation des plantes médicinales à coumarines des marchés de Douala Est (Cameroun). 7810. Flatulences. Feuilles fraiches, graines. Décoction (1,5 l d'eau avec. 750 ml pendant 30 mn, y ajouter du jus de carotte et de céleri). Voie orale (boire 1 verre tous les matins).

  17. Author Details

    African Journals Online (AJOL)

    ... en béton armé préfissurées renforcées par un matériau composite en toile de fibres de carbone (TFC) Abstract PDF · Vol 24 (2015) - Articles Impact de la fatigue et du vieillissement hygrothermique en eau douce sur un composite unidirectionnel verre-époxy. Abstract PDF. ISSN: 2352-9717. AJOL African Journals Online.

  18. Study on the formation of heterogeneous structures in leached layers during the corrosion process of glass

    Directory of Open Access Journals (Sweden)

    Willemien Anaf


    Full Text Available Le verre, corrodé dans des conditions naturelles, montre souvent des hétérogénéités dans la couche lixiviée, comme une structure lamellaire ou des inclusions de MnO2 ou Ca3(PO42. La formation de ces hétérogénéités n’est pas encore bien comprise. Des structures de ce type ont été produites artificiellement en laboratoire en immergeant des échantillons de verre dans des solutions riches en métaux. Les résultats expérimentaux ont été comparés avec des théories décrivant la corrosion du verre.Glass that corrodes under natural conditions often shows heterogeneities in the leached layer, such as a lamellar structure or inclusions of MnO2 or Ca3(PO42. The formation of these heterogeneities is still not well understood. By means of experiments under laboratory conditions, our aim was to artificially generate specific structures. Therefore, glass samples were immersed in metal-rich solutions. The experimental results were compared with theories describing glass corrosion from a molecular point of view.

  19. Report on the scientific feasibility of new matrices for the conditioning of long lived radionuclides; Rapport sur la faisabilite scientifique des matrices nouvelles de conditionnement des radionucleides a vie longue

    Energy Technology Data Exchange (ETDEWEB)



    New specific matrices for the conditioning of long lived radionuclides (I, Cs, Tc, minor actinides) have been developed. This report presents the conditions of their synthesis by sintering or melting and the quantifying of their crystallographic, physical and thermal properties. A 7% mass insertion of iodine can be reached with a phosphorus-vanadium-lead iodo-apatite. A 5% mass insertion of cesium is reached with the hollandite-type crystal structure (barium aluminate-titanate). An insertion level of at least 10% mass of rare earth oxides (simulating the presence of actinides) is reached for britholite, zirconolite, thorium phosphate, monazite, and zirconolite glass/ceramic materials. The chemical durability has been also determined. Enhanced aqueous corrosion resistance, 100 times better than for the glasses used today, are obtained for iodo-apatite (I), hollandite (Cs), britholite (actinides 3+/4+), thorium phosphate (actinides 4+) and monazite (3+/4+). The first elements of stability with respect to irradiation are reported for the minor actinide conditioning matrices. External post-irradiation examinations by heavy ion bombardment coupled to atomistic modeling have been performed. The characterization of self-irradiated natural analogues of britholite, zirconolite and monazite with more than 10{sup 20} {alpha}/g disintegrations confirms the very long time stability of these mineral structures (>10{sup 8} years). On the basis of the obtained results, it appears that the iodo-apatite, britholite, zirconolite, and thorium phosphate conditioning matrices have reached the stage of scientifical feasibility. The monazite matrice is on the way to reach the feasibility too. Other specific matrices for technetium (metal alloys) and cesium (hollandite) are also under development, but their long-term properties remain to be determined. (J.S.)

  20. Naturally occurring crystalline phases: analogues for radioactive waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Haaker, R.F.; Ewing, R.C.


    Naturally occurring mineral analogues to crystalline phases that are constituents of crystalline radioactive waste forms provide a basis for comparison by which the long-term stability of these phases may be estimated. The crystal structures and the crystal chemistry of the following natural analogues are presented: baddeleyite, hematite, nepheline; pollucite, scheelite;sodalite, spinel, apatite, monazite, uraninite, hollandite-priderite, perovskite, and zirconolite. For each phase in geochemistry, occurrence, alteration and radiation effects are described. A selected bibliography for each phase is included.

  1. New conditioning for enhanced separated long lived radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Advocat, T.; Fillet, C.; Bart, F.; Leturcq, G. [CEA Marcoule, Dept. d' Ingenierie et d' Etudes des Confinements DIEC, 30 (France); Audubert, F.; Lartigue, J.E.; Bertolus, M.; Campayo, L.; Guy, C. [CEA Cadarache, Dept. d' Etudes des Dechets DED, 13 - Saint Paul lez Durance (France)


    Long lived radionuclides such as I, Cs, and minor actinides can be conditioned in the crystalline structures of several specific materials, with high chemical durability. It was determined that apatite structures can incorporate iodine (up to 7 wt.%) when phosphate groups are combined with vanadate groups. Barium Hollandite-based ceramics have been investigated to confine cesium (1.6 wt.% Cs). Britholites and zirconolite-based ceramics can confine significant quantities (up to 10 wt.% oxide) of trivalent and tetravalent actinide surrogates such as REE's. (authors)

  2. FY16 Annual Accomplishments - Waste Form Development and Performance: Evaluation Of Ceramic Waste Forms - Comparison Of Hot Isostatic Pressed And Melt Processed Fabrication Methods

    Energy Technology Data Exchange (ETDEWEB)

    Amoroso, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dandeneau, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    FY16 efforts were focused on direct comparison of multi-phase ceramic waste forms produced via melt processing and HIP methods. Based on promising waste form compositions previously devised at SRNL, simulant material was prepared at SRNL and a portion was sent to the Australian Nuclear Science and Technology Organization (ANSTO) for HIP treatments, while the remainder of the material was melt processed at SRNL. The microstructure, phase formation, elemental speciation, and leach behavior, and radiation stability of the fabricated ceramics was performed. In addition, melt-processed ceramics designed with different fractions of hollandite, zirconolite, perovskite, and pyrochlore phases were investigated. for performance and properties.

  3. Topography and Mechanical Property Mapping of International Simple Glass Surfaces with Atomic Force Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, Eric M [ORNL


    Quantitative Nanomechanical Peak Force (PF-QNM) TappingModeTM atomic force microscopy measurements are presented for the first time on polished glass surfaces. The PF-QNM technique allows for topography and mechanical property information to be measured simultaneously at each pixel. Results for the international simple glass which represents a simplified version of SON68 glass suggests an average Young s modulus of 78.8 15.1 GPa is within the experimental error of the modulus measured for SON68 glass (83.6 2 GPa) with conventional approaches. Application of the PF-QNM technique will be extended to in situ glass corrosion experiments with the goal of gaining atomic-scale insights into altered layer development by exploiting the mechanical property differences that exist between silica gel (e.g., altered layer) and pristine glass surface.

  4. Characterization of Ceramic Material Produced From a Cold Crucible Induction Melter Test

    Energy Technology Data Exchange (ETDEWEB)

    Amoroso, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Marra, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    This report summarizes the results from characterization of samples from a melt processed surrogate ceramic waste form. Completed in October of 2014, the first scaled proof of principle cold crucible induction melter (CCIM) test was conducted to process a Fe-hollandite-rich titanate ceramic for treatment of high level nuclear waste. X-ray diffraction, electron microscopy, inductively coupled plasma-atomic emission spectroscopy (and inductively coupled plasma-mass spectroscopy for Cs), and product consistency tests were used to characterize the CCIM material produced. Core samples at various radial locations from the center of the CCIM were taken. These samples were also sectioned and analyzed vertically. Together, the various samples were intended to provide an indication of the homogeneity throughout the CCIM with respect to phase assemblage, chemical composition, and chemical durability. Characterization analyses confirmed that a crystalline ceramic with desirable phase assemblage was produced from a melt using a CCIM. Hollandite and zirconolite were identified in addition to possible highly-substituted pyrochlore and perovskite. Minor phases rich in Fe, Al, or Cs were also identified. Remarkably only minor differences were observed vertically or radially in the CCIM material with respect to chemical composition, phase assemblage, and durability. This recent CCIM test and the resulting characterization in conjunction with demonstrated compositional improvements support continuation of CCIM testing with an improved feed composition and improved melter system.


    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Brinkman, K.


    The Savannah River National Laboratory (SRNL) is developing crystalline ceramic waste forms to incorporate CS/LN/TM high Mo waste streams consisting of perovskite, hollandite, pyrochlore, zirconolite, and powellite phase assemblages. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase crystalline ceramics. Fiscal Year 2011 (FY11) activities included (i) expanding the compositional range by varying waste loading and fabrication of compositions rich in TiO{sub 2}, (ii) exploring the processing parameters of ceramics produced by the melt and crystallize process, (iii) synthesis and characterization of select individual phases of powellite and hollandite that are the target hosts for radionuclides of Mo, Cs, and Rb, and (iv) evaluating the durability and radiation stability of single and multi-phase ceramic waste forms. Two fabrication methods, including melting and crystallizing, and pressing and sintering, were used with the intent of studying phase evolution under various sintering conditions. An analysis of the XRD and SEM/EDS results indicates that the targeted crystalline phases of the FY11 compositions consisting of pyrochlore, perovskite, hollandite, zirconolite, and powellite were formed by both press and sinter and melt and crystallize processing methods. An evaluation of crystalline phase formation versus melt processing conditions revealed that hollandite, perovskite, zirconolite, and residual TiO{sub 2} phases formed regardless of cooling rate, demonstrating the robust nature of this process for crystalline phase development. The multiphase ceramic composition CSLNTM-06 demonstrated good resistance to proton beam irradiation. Electron irradiation studies on the single phase CaMoO{sub 4} (a component of the multiphase waste form) suggested that this material exhibits stability to 1000 years at anticipated self-irradiation doses (2 x 10{sup 10}-2 x 10{sup 11} Gy), but that

  6. El vidrio en la construcción. Situación actual y orientación de la l+D

    Directory of Open Access Journals (Sweden)

    Coto, José Antonio


    Full Text Available Not available.

    El vidrio, bajo sus diferentes formas y composiciones, constituye uno de los materiales más utilizados en la construcción. Desempeña múltiples funciones: Estética, Confort, Seguridad,... Aunque se trata de un material muy antiguo, gracias al esfuerzo de l+D, está teniendo una importante evolución durante estos últimos años. Se desarrollan nuevas propiedades y funciones mediante modificaciones en su composición, tratamientos de su superficie o asociación con otros productos. Se recoge, en esta comunicación, un extenso número de nuevos productos y sus procedimientos de obtención, destacando su aplicación y funcionalidad en la construcción. Se da cierta extensión a los diferentes tratamientos de superficie (principalmente, capas delgadas sobre vidrio plano, por su especial implantación en la construcción actual. Igualmente, se describen los productos compuestos y sus utilizaciones más funcionales. Los vidrios con propiedades variables a voluntad son objeto de múltiples desarrollos actuales y, sin duda, serán de gran aplicación en la construcción en un futuro próximo. Se termina esta comunicación con una referencia, necesariamente breve, a los vidrios estructurales y las diferentes fibras de vidrio (tanto de aislamiento térmico y acústico, como de refuerzo, también de gran interés y difusión en la construcción. [fr] Le verre dans la construction. Situation actuelle et orientation de la R+D. Le verre, sous des formes et compositions différentes, représente un matériau très utilisé dans le bâtiment. Ses fonctions sont multiples: Esthétique, Confort, Sécurité, ... Bien qu'il s'agit d'un matériau très ancien, grâce a l'effort de R+D, son évolution pendant les dernières années a été très importante. On a développé de nouvelles propriétés et fonctions en modifiant la composition, les traitements de surface ou l'association avec d'autres produits. Dans cette

  7. Çocukluk Çağında Anogenıtal Verru ve Cinsel İstismar

    Directory of Open Access Journals (Sweden)

    Dua Sumeyra Demirkıran


    Full Text Available Çocuklarda anogenital bölgede cinsel yolla bulaşan hastalıkların varlığı cinsel istismarın delilidir. Human papilloma virüs (HPV yetişkinlerin %80 ini etkileyen, en sık görülen cinsel yolla geçen hastalık kabul edilmektedir. Bu virüsün oluşturduğu verrülerin çocuklarda görülmesi cinsel istismar kanısı oluşturmaktadır. Çalışmamızda anogonital verrü (AGV ile ilgili literatür derlemesi yaparak AGV'li çocuk olgularına adli tıp yönünden yaklaşım önerilerini sunmayı amaçladık. Yapılan çalışmalara göre HPV'nin cinsel istismar dışında farklı bulaş yollarının olduğu bilimsel olarak saptanmıştır. Bu nedenle AGV'li çocuklara yaklaşımda cinsel istismar ön yargısının kırılması gerektiği kanaati oluşmuştur. Çocukların ve ailelerin "cinsel istismar" psikolojisinden uzak tutulmalıdır. Bu olgulara multidisipliner yaklaşılarak bulaş yolu hakkında kanaat oluştuktan sonra adli olgu açısından değerlendirilmelidir. Anahtar kelimeler: anogenital verrü, bulaş yolları, cinsel istismar

  8. 22 Étude des propriétés structurales, optiques et électriques des ...

    African Journals Online (AJOL)

    herve tchognia

    Les couches minces de ZnO dopées Aluminium (AZO) ont été déposées par la technique spray pyrolysis sur des substrats de verre ordinaire préchauffés à la température de 425°C. Des solutions aqueuses de chlorure de zinc de concentration 0.1M et dopées à partir du nitrate d'aluminium ont été utilisées pour le dépôt.

  9. Étude des propriétés structurales, optiques et électriques des ...

    African Journals Online (AJOL)

    Les couches minces de ZnO dopées Aluminium (AZO) ont été déposées par la technique spray pyrolysis sur des substrats de verre ordinaire préchauffés à la température de 425°C. Des solutions aqueuses de chlorure de zinc de concentration 0.1M et dopées à partir du nitrate d'aluminium ont été utilisées pour le dépôt.

  10. Lithogenic fluxes to the deep Arabian Sea measurEd. by sediment traps

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Nair, R.R.; Manganini, S.J.; Haake, B.; Ittekkot, V.

    al., 1981a; CAt,VERr, 1987). Mineralogy X-ray diffractien studies of the trap samples show illitc to bc the most dominant mineral, ranging from 25 to 50% (Table la--c). The other minerals identified are quartz, feldspar, smectitcs, mixcd layer... Arabian Sea sediments. Indian Jottrnal of Marine Science. I I. 514~2. Cat.vl~rr S. E. (1987) Oceant)graphic controls on the accumulatiun of organic matter in marine sediments. In: Marine pctroh'am source rocks. J. BItooKs :rod A. J. Ft.t~t~r, editors...

  11. spin coating

    African Journals Online (AJOL)


    Dans ce travail nous avons préparé des couches minces de l'oxyde de zinc ZnO dopées à l'aluminium et non dopées par la technique Sol-Gel associée au « spin coating » sur des substrats en verre « pyrex » à partir de l'acétate de zinc dissous dans une solution de l'éthanol. Nous avons ensuite effectué des analyses ...

  12. Étude floristique et ethnobotanique de la flore médicinale dans la ...

    African Journals Online (AJOL)


    30 sept. 2015 ... seule ou bien suivie du jaune d'un œuf ou d'un verre de thé contre la tuberculose pulmonaire. La poudre mélangée avec l'Ail (Allium sativa L.) et l'huile d'olive est conseillé le matin contre la tuberculose et le refroidissement. Fagaceae. Quercus suber L. (Chéne-liége, Dbagh). Le décocté de l'écorce des ...

  13. Propriétés structurales, optiques et électriques des couches minces

    African Journals Online (AJOL)

    SEI Joseph

    Des couches minces de TiO2 dopé au cuivre ont été préparées par la méthode Sol-Gel et déposées selon le procédé dip-coating sur des substrats en verre. Les propriétés structurales, optiques et électriques des échantillons monocouches dopés 0, 3 et 7 % at. cuivre ont été analysées par diffraction des rayons X (DRX),.

  14. Inhabiting adaptive architecture


    Schnädelbach, Holger


    Adaptive Architecture concerns buildings that are specifically designed to adapt to their inhabitants and to their environments. Work in this space has a very long history, with a number of adaptive buildings emerging during the modernist period, such as Rietveld’s Schröder house, Gaudi’s Casa Batlló and Chareau's Maison de Verre. Such early work included manual adaptivity, even if that was motor-assisted. Today, buildings have started to combine this with varying degrees of automation and de...

  15. La trasformazione dal DATUM catastale ai DATUM Roma 1940 e ETRF2000

    Directory of Open Access Journals (Sweden)

    Alberto Cina


    Full Text Available Nell’articolo verrà esposta una procedura geodetica di trasformazione dal DATUM catastale, verso il DATUM Roma 1940 oltre che ETRF2000, messa a punto presso il Politecnico di Torino – DIATI. Essa è stata applicata nella Regione Piemonte, realtà particolarmente complessa per la consistente presenza di sistemi d’asse di piccola estensione (circa 540, dopo una sperimentazione eseguita nell’ambito di una collaborazione scientifica tra l’Agenzia del Territorio e il Politecnico di Torino – DIATI e in base ad un accordo tra Politecnico di Torino, Regione Piemonte e CSI Piemonte.

  16. Le ex-colonie italiane nei racconti orali di Ribka Sibhatu e Kaha Mohamed Aden: I documentari La Quarta via. Mogadiscio, Italia e Aulò. Roma post-coloniale

    Directory of Open Access Journals (Sweden)

    Kombola Ramadhani Mussa


    Full Text Available La recensione dei due documentari La quarta via: Mogadiscio, Pavia e Aulò: Roma Postcoloniale è finalizzata a metterne in luce il valore testimoniale. Il racconto orale di Kaha Mohamed Aden, originaria della Somalia, e Ribka Sibhatu, originaria dell’Eritrea, due scrittrici da tempo risiedenti in Italia, attraverso la memoria e la condivisione delle loro esperienze personali, permette di recuperare il passato coloniale italiano, mettere in discussione il presente e, in particolare, le questioni relative alla migrazione italiana. I due documentari, inoltre, forniscono interessanti chiavi di lettura per comprendere e prepararci con una nuova consapevolezza critica a quello che verrà.

  17. 2181-IJBCS-Article-Halima El Hadji

    African Journals Online (AJOL)


    90 et 100 mM. ; 3% de sucre et 7 grammes d'agar agar par litre de milieu. Après avoir ajusté le pH à 5,8, le milieu a été autoclavé à. 120 °C pendant une durée de 20 minutes. Un volume de 25 ml de milieu a été coulé dans chacun des flacons en verre de 250 ml. Après une désinfection rapide avec de l'éthanol à.

  18. Combat Aircraft Maneuverability. (United States)


    interm~diaire. Ceci a 6t6 trait6 dans certains sympo- siums du Propulsion and Energetics Panel. II faut Egalement prendre en considdration le bilan pouss...R.D. CHILD, G. PANACEAS et P. GINGRICH (Rdf. 10) (Fig. 61) A propas du v~hicule tdldpilot6 Hi Mat. On doit jssn~diatement y associer le bilan pauss~e...formiage, fibres de verre. de carbone , Kevlar) afind’accrcttre au maximum lee capacitie d’emport du fuselage qui se trouve ainsi creux at tr~s l6ger tout en

  19. Correction de front d'onde d'une impulsion femtoseconde durant la génération de second harmonique dans un cristal doubleur (United States)

    Caumes, J.-P.; Videau, L.; Rouyer, Cl.; Freysz, E.


    Nous démontrons que la génération de second harmonique au voisinage de la condition d'accord de phase dans un cristal de BBO de 2 mm d'épaisseur permet la correction du front de l'onde d'une impulsion laser intense ayant traversée un morceau de verre de silice de 4 cm d'épaisseur. Cette démonstration est effectuée en enregistrant la déformation du front d'onde avec un analyseur de surface d'onde.

  20. Resistance, fiabilité et longévité de plastiques renforces comme ...

    African Journals Online (AJOL)

    Le but du travail est la construction d'une approche générale permettant de prendre en considération les particularités de la résistance à la rupture, la fiabilité et la longévité des stratifiés à base de tissus de verre utilisés à la construction navale avec l'examen de certaines particularités du comportement. Mots clés: stratifié à ...


    Directory of Open Access Journals (Sweden)



    par évaporation sur des substrats en verre présentent des coefficients d’absorption ( élevées de l’ordre de 5.104 cm-1. Le tracé de la fonction (h2 des couches minces recuites sous vide à différentes températures en fonction de l’énergie des photons incident a mis en relief la nature directe de la transition fondamentale est a permis également de calculer le gap Eg = 1.04 eV.

  2. Images in medicine

    African Journals Online (AJOL)


    15 janv. 2015 ... hyperdensités en verre dépoli diffuse (C). L'exploration fonctionnelle respiratoire mettait en évidence un trouble ventilatoire restrictif avec une baisse de la capacité vitale de 35%. La gazométrie artérielle au repos a retrouvé une hypoxémie à 55 mmHg de PaO2. L'interrogatoire poussé nous fait découvrir la ...

  3. MAQUETTE ORL Décembre 2004

    African Journals Online (AJOL)

    le chez 30 malades et partielle chez 17malades. Chez 4 malades la déformation de la pyramide nasale a été le motif de consultation. Les signes dʼhyper réactivité nasale à type de prurit nasal ont été retrouvés chez 6 malades. A lʼexamen physique nous avons trouvé une déviation de la cloison nasale en verre de montre ...

  4. Op weg na ’n Christelikke argeologiese wetenskap

    Directory of Open Access Journals (Sweden)

    J. H. Booyens


    Full Text Available Argeologie kan omskryf word as die studie van die menslike verlede soos dit op direkte en indirekte wyse weerspieel word in oorblyfsels van kultuurskeppinge en -aktiwiteite. Die veld van ondersoek van argeologie is egter nie slegs beperk tot die verre verlede nie, maar strek in beginsel oor die hele tydsduur van waameembare menslike aktiwiteit. Argeoloe onderskei dikwels hiervolgens tussen prehistoriese, protohistoriese en historiese argeologie. Die sentrale onderskeidende faktor is die aan- of afwesigheid van skrif. ’n Ander sienwyse is dat daar net tussen primêre en sekondêre prehistorie, onderskei moet word.

  5. Mesure du Deplacement de Frequence au Maximum de la Raie P20 un Laser CO2 a Ondes Guidees (Measurement of the Frequency Shift at the Peak of the P20 Line of a CO2 Waveguide Laser), (United States)


    6galement de bien cerner le maximum d𔄀mission de la rate P20 du mode fondamental; une stabilisation au maximum de la rate peut etre l4 rement fauss~e par...pourquoi nous avons utilisg par la suite un r~gulateur thermique beaucoup plus sta- ble. Ce travail porte surtout sur la variation de la fr~quence de...fondamental de la raie * .P20. On note 6galement les r~sultats obtenus avec un guide d’ondes en verre. a SANS CLASSIFICATION 2 Ce travail a 6t effectu6

  6. L'ordre du chaos

    CERN Document Server


    Le mouvement brownien ; la mémoire des atomes ; le chaos ; déterminisme et prédictabilité ; déterminisme et chaos ; les phénomènes de physique et les échelles de longueur ; un ordre caché dans la matière désordonnée ; les verres de spin et l'étude des milieux désordonnés ; la convection ; la croissance fractale ; la physique de la matière hétérogène ; la matière ultradivisée.

  7. Mécanismes et cinétique de dissolution de matériaux phosphatés cristallisés et amorphes en milieux acides chlorhydrique et citrique.


    Thirioux, Laurence



  8. Tanzendes Tier oder exzentrische Positionalität - Philosophische Anthropologie zwischen Darwinismus und Kulturalismus (United States)

    Fischer, Joachim

    Zunächst kurz vorweg zu den Formeln im Titel: "exzentrische Positionalität“ ist der Kategorienvorschlag der Philosophischen Anthropologie (genauer: von Helmuth Plessner) für den Menschen, für seine "Sonderstellung“ unter den Lebewesen - ich werde diesen Begriff erläutern. So viel kann man sagen: Der Terminus ist nicht schwieriger als "Transzendentalität“ oder das "Apriori“ oder "Autopoiesis“, also Begriffe, mit deren Orientierungswert in der intellektuellen Öffentlichkeit bereits gespielt wird, bietet aber möglicherweise mehr Erschließungskraft als die Kunstbegriffe z. B. von Kant, Maturana oder Luhmann. Und "tanzendes Tier“ ist ein glücklicher Anschauungsbegriff, eine Art Übersetzung für "exzentrische Positionalität“ - also ein "verrücktes“ Lebewesen, eine Verrückung im evolutionären Leben, die dieses Lebewesen von Natur aus zu einer bestimmten Art von Lebensführung, nämlich Kultur nötigt. Die Absicht des Beitrages ist es, die Philosophische Anthropologie als eine spezifische Theorietechnik zu präsentieren, um einen adäquaten Begriff des Menschen zu erreichen, und zwar eine Theoriestrategie angesichts des cartesianischen Dualismus - also des Dualismus zwischen Naturalismus und Kulturalismus.

  9. Il gradiente implicito nella verifica a fatica di giunzioni saldate sollecitate a fatica

    Directory of Open Access Journals (Sweden)

    R. Tovo


    Full Text Available L’incremento delle potenzialità di strumenti per la progettazione assistita (come modellatori solidi e strumenti per FEA in grado di gestire modelli molto complessi permette di ipotizzare lo sviluppo di strumenti numerici specifici per la previsione della resistenza a fatica delle giunzioni saldate. Tali strumenti potrebbero essere in grado di valutare l’influenza di geometria e carichi senza la necessità di elaborazioni successive, e spesso, del progettista (come nelle tensioni di Hot Spot. Il presente lavoro propone una metodologia di calcolo adatta alla previsione della vita a fatica di giunzioni saldate complesse. Un indice di resistenza è ottenuto innanzitutto risolvendo il problema tensionale completamente in modo numerico (agli elementi finiti. La previsione della resistenza a fatica, è calcolata facendo uso di un modello analitico basato sul gradiente implicito che assume come tensione efficace la tensione equivalente non locale derivante dalla tensione principale. Dapprima verrà tarato il metodo su prove sperimentali eseguite su giunzioni saldate a croce, successivamente il metodo verrà utilizzato per la verifica a fatica di giunzioni saldate più complesse a sviluppo tridimensionale.

  10. Un nouveau cristal laser largement accordable le BOYS dopé à l'ytterbium (United States)

    Chénais, S.; Druon, F.; Balembois, F.; Georges, P.; Gaumé, R.; Aka, G.; Viana, B.; Vivien, D.


    Nous avons étudié les performances laser en pompage par diode de puissance d'un nouveau cristal : le Sr3Y(BO3)3 (acronyme : BOYS), dopé à l'ytterbium. Son spectre d'émission particulièrement large en fait un matériau particulièrement prometteur pour la réalisation de lasers femtosecondes directement pompés par diode. Ses performances ont été comparées à celles d'un verre phosphate ainsi qu'à celles du cristal d' Yb:GdCOB dans les mêmes conditions. Nous démontrons que, tant du point de vue de l'efficacité laser que de la tenue aux fortes puissances, GdCOB et BOYS sont supérieurs au verre ; le BOYS est de surcroît plus accordable (sur 50 nm), mais son comportement thermique limite a priori son usage à des puissances de pompe modérées.

  11. Le Corbusier, Pierre Chareau and two masterpieces of modern architecture

    Directory of Open Access Journals (Sweden)

    Sílvia Amaral Palazzi Zakia


    Full Text Available Le Corbusier and Pierre Chareau are famously responsible for two projects considered iconic of modern architecture: Villa Savoye and Maison de Verre. Both are coeval and commissioned by clients with the same socioeconomic profile – the French haute bourgeoisie –, and with similar needs. Villa Savoye is a single family home, while Maison de Verre houses both residential and medical clinic functions in the same building structure. However, this difference does not interfere in our intended analysis. By comparing the client-architect relationships in both projects – Le Corbusier/Savoye and Chareau/Dalsace – we raise  questions regarding the professional behavior that modern architects have arrogated to themselves: to revolutionize customs and practices. The projects are modern and diverse responses to similar requests. In both cases, the role of women is indicative of their influence in that particular historical context as opinion setters. The house is the locus of the female dominium, and as such expresses women’s tastes and habits.

  12. Materiaux composites supraconducteurs (United States)

    Kerjouan, Philippe; Boterel, Florence; Lostec, Jean; Bertot, Jean-Paul; Haussonne, Jean-Marie


    The new superconductor materials with a high critical current own a large importance as well in the electronic components or in the electrotechnical devices fields. The deposit of such materials with the thick films technology is to be more and more developped in the years to come. Therefore, we tried to realize such thick films screen printed on alumina, and composed mainly of the YBa2CU3O{7-δ} material. We first realized a composite material glass/YBa2CU3O{7-δ}, by analogy with the classical screen-printed inks where the glass ensures the bonding with the substrate. We thus realized different materials by using some different classes of glass. These materials owned a superconducting transition close to the one of the pure YBa2CU3O{7-δ} material. We made a slurry with the most significant composite materials and binders, and screen-printed them on an alumina substrate preliminary or not coated with a diffusion barrier layer. After firing, we studied the thick films adhesion, the alumina/glass/composite material interfaces, and their superconducting properties. Les nouveaux matériaux supraconducteurs à haute température critique ont potentiellement un rôle important à jouer dans le domaine de l'électronique et de l'électrotechnique. En particulier, le dépôt d'oxydes supraconducteurs sur divers types de substrats est une technologie amenée à se développer. Nous avons donc entrepris une étude dont l'objet est la réalisation de conducteurs sérigraphiés sur alumine et composés essentiellement du matériau YBa2CU3O{7-δ}. Nous avons tout d'abord cherché à réaliser un composite verre/YBa2CU3O{7-δ}, par analogie au principe de réalisation de couches conductrices sérigraphiées, le verre permettant d'obtenir une liaison physico-chimique avec le substrat. Une étude préliminaire a permis de réaliser divers matériaux composites massifs, utilisant différentes familles de verres. Ces matériaux massifs, se présentant sous la forme de barreaux de

  13. Subduction recycling of continental sediments and the origin of geochemically enriched reservoirs in the deep mantle

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, R.P.; Irifune, T.; Shimizu, N.; Nishiyama, N.; Norman, M.D.; Inoue, T. (Ehime U); (WHOI); (UC); (ANU)


    the product of melting of deeply recycled (subducted) Archean-age metasediments in the mantle transition zone [Murphy, D.T., Collerson, K.D., Kamber, B.S., 2002. Lamproites from Gaussberg, Antartica: possible transition zone melts of Archaean subducted sediments. J. Petrol. 43, 981-1001]. Here we report the results of phase equilibria experiments on two different natural sedimentary compositions (a high-grade metapelite with < 1 wt.% H{sub 2}O, and a marine 'mud' with 8 wt.% H{sub O}) at 16-23 GPa. In both materials, the high-pressure mineral assemblages contain {approx} 15-30 wt.% K-hollandite (KAlSi{sub 3}O{sub 8}), in addition to stishovite, garnet, an Al-silicate phase (kyanite or phase egg), and a Fe-Ti spinel (corundum). Ion microprobe analyses of K-hollandite for a range of trace elements reveal that this phase controls a significant proportion of the whole-rock budget of incompatible, large-ion lithophile elements (LILEs, e.g., Rb, Ba, Sr, K, Pb, La, Ce and Th). Comparisons between the abundances and ratios of these elements in K-hollandite with those in EM-I type ocean-island basalts from Pitcairn Island and related seamounts, and with the Gaussberg lamproites, indicate the presence of deeply recycled, continent-derived sediments in these lavas sources. Our results suggest that the incompatible trace-element signature of EM-I OIB reservoirs in general and of the Gaussberg lamproites in particular can be attributed to recycling of K-hollandite-bearing continental sediments to transition zone depths.

  14. Alternative High-Performance Ceramic Waste Forms

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, S. K. [Alfred Univ., NY (United States)


    This final report (M5NU-12-NY-AU # 0202-0410) summarizes the results of the project titled “Alternative High-Performance Ceramic Waste Forms,” funded in FY12 by the Nuclear Energy University Program (NEUP Project # 12-3809) being led by Alfred University in collaboration with Savannah River National Laboratory (SRNL). The overall focus of the project is to advance fundamental understanding of crystalline ceramic waste forms and to demonstrate their viability as alternative waste forms to borosilicate glasses. We processed single- and multiphase hollandite waste forms based on simulated waste streams compositions provided by SRNL based on the advanced fuel cycle initiative (AFCI) aqueous separation process developed in the Fuel Cycle Research and Development (FCR&D). For multiphase simulated waste forms, oxide and carbonate precursors were mixed together via ball milling with deionized water using zirconia media in a polyethylene jar for 2 h. The slurry was dried overnight and then separated from the media. The blended powders were then subjected to melting or spark plasma sintering (SPS) processes. Microstructural evolution and phase assemblages of these samples were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion analysis of x-rays (EDAX), wavelength dispersive spectrometry (WDS), transmission electron spectroscopy (TEM), selective area x-ray diffraction (SAXD), and electron backscatter diffraction (EBSD). These results showed that the processing methods have significant effect on the microstructure and thus the performance of these waste forms. The Ce substitution into zirconolite and pyrochlore materials was investigated using a combination of experimental (in situ XRD and x-ray absorption near edge structure (XANES)) and modeling techniques to study these single phases independently. In zirconolite materials, a transition from the 2M to the 4M polymorph was observed with increasing Ce content. The resulting

  15. Physics colloquium: Electron counting in quantum dots in and out of equilibrium

    CERN Multimedia

    Geneva University


    GENEVA UNIVERSITY Ecole de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92olé   Lundi 31 octobre 2011 17h00 - Ecole de Physique, Auditoire Stueckelberg PHYSICS COLLOQUIUM « Electron counting in quantum dots in and out of equilibrium » Prof. Klaus Ensslin Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland   Electron transport through quantum dots is governed by Coulomb blockade. Using a nearby quantum point contact the time-dependent charge flow through quantum dots can be monitored on the basis of single electrons. This way electron transport has been investigated in equilibrium as well as out of equilibrium. Recently it has become possible to experimentally verify the fluctuation theorem. The talk will also address electron counting experiments in grapheme. Une verrée ...

  16. Ol'ga Slivickaja, Un ‘incontro ideale’: Lermontov e Tolstoj

    Directory of Open Access Journals (Sweden)

    Elizaveta Illarionova


    Full Text Available Il saggio indaga l’antropologia culturale in Un eroe del nostro tempo di Lermontov a confronto con i romanzi di Tolstoj. L’analisi della novella Maksim Maksimyč permette di scoprire nella contrapposizione di Pečorin e Maksim Maksimyč il tema del conflitto culturale tra un uomo eccezionale e un «uomo semplice» e, in una visione più ampia, tra l’intelligencija e il popolo. Tale conflitto, irrisolto nel romanzo di Lermontov ad eccezione del tema del fatalismo comune a tutti i personaggi, verrà sanato nella figura di Pierre Bezuchov di Guerra e pace. In conclusione, si riafferma il duplice ruolo di Lermontov come antesignano di Tolstoj ma anche artista autonomo dalle scelte artistiche non inferiori ma radicalmente diverse da quelle tolstoiane.

  17. Interfon

    CERN Multimedia



    Prochaine journée « Portes ouvertes » Mercredi 5 octobre de 16 h 00 à 20 h 00 Salle Jean Monnet à St-Genis Au cours de laquelle vous pourrez rencontrer nos partenaires devant un agréable buffet campagnard. Notre nouveau partenaire Centre commercial de ValThoiry     Tourné vers le bien-être, Lissac propose notamment une collection aussi légère qu’une… plume ! Ces montures « aériennes » (10 g en moyenne) se déclinent en 8 formes et 8 couleurs, pour répondre à toutes les envies : petites formes tendances, design étudié pour les verres progressifs, habillage des branches, etc. - 10% sur tous vos achats * * * * * Savoie Cheminées nous informe … L'entreprise Savoie Cheminées dépositaire des cheminées BRISA...

  18. Présentation : réflexions sur le miroir


    Pomel, Fabienne


    L’objet Si le Moyen Âge connaît comme l’Antiquité les miroirs métalliques généralement petits et bon marché, il voit le développement des miroirs de cristal de roche et de verre, parallèlement à l’essor de l’optique au xiiie siècle dans le sillage des travaux de l’Arabe Alhazen, de Robert Grossetête, Guillaume Peckam ou Vitellion. Le miroir métallique, rarement sans taches à cause de l’oxydation, est généralement de qualité médiocre. De plus, ses formes varient : le miroir peut être s...

  19. Le massacre de la mariée

    Directory of Open Access Journals (Sweden)

    Bastiaan van der Velden


    Full Text Available Le Massacre des innocents a été pour Marcel Duchamp l’une de ses sources en composant Le Grand Verre. Ce ‘massacre’ est dans ce cas plus précisément une attraction foraine. D’autre part l’infanticide à Bethlehem constitue un sujet maintes fois représenté par différents peintres. Pour Alfred Jarry, auteur littéraire et de théâtre qui a plus particulièrement inspiré Duchamp, le tableau Le Massacre des innocents de Breughel l’Ancien était une pièce clé qui lui permettait de démontrer pourquoi il rejetait l’art historisant en peinture et dans le théâtre.

  20. Ein unbekanntes Meisterwerk altdeutscher Glaskunst: Hans Wertingers gläserne Hostienschale von 1498

    Directory of Open Access Journals (Sweden)

    Koreny, Fritz


    Full Text Available This hitherto unknown glass paten with églomisé painting, dated 1498 and measuring 36 cm in diameter, depicts the meeting of Abraham and Melchisedek. The painting can be attributed to Hans Wertinger, an artist from Landshut, who is well known for his paintings and stained glass. The recently discovered paten is executed in a refined églomisé technique with painting, scratching-out and with underlayers of gold and silver leaf, making it one of the earliest and finest examples of this technique, not only for Bavarian early Renaissance art but worldwide. The paten thus sheds fresh light on Wertinger as it shows him as an highly trained artist who worked also with bravura in the art of verre églomisé.

  1. La Luxure, Jacques Demy, 1961


    Marie, Michel


    Voici d’abord un petit résumé du film, qui n’est quand même pas des plus connus, parmi les courts métrages de Jacques Demy. Paris, un jour d’été ensoleillé. Deux copains se retrouvent dans une rue du Quartier Latin. Jacques (Laurent Terzieff) passe son temps à aborder les filles qu’il croise. Jacques et Bernard (Jean-Louis Trintignant) évoquent l’un de leurs copains, René. Bernard achète un livre sur le peintre Jérôme Bosch. Ils vont prendre un verre ensemble sur les quais et feuillètent le l...

  2. Geneva University: Experiments in Physics: Hands-on Creative Processes

    CERN Multimedia

    Université de Genève


    Geneva University Physics Department 24, quai Ernest-Ansermet CH-1211 Geneva 4 Tel: (022) 379 62 73 Fax: (022) 379 69 92   Lundi 3 octobre 2011, 17h00 Ecole de Physique, Auditoire Stueckelberg «Experiments in Physics : Hands-on Creative Processes» Prof. Manfred Euler Leibniz-Institute for Mathematics and Science Education (IPN) University of Kiel, Deutschland Experiments play a variety of different roles in knowledge generation. The lecture will focus on the function of experiments as engines of intuition that foster insights into complex processes. The experimental presentations consider self-organization phenomena in various domains that range from the nanomechanics of biomolecules to perception and cognition. The inherent universality contributes to elucidating the enigmatic phenomenon of creativity. Une verrée en compagnie du conférencier sera offerte après le colloque.       &...

  3. Etude expérimentale et modélisation du comportement en fatigue multiaxiale d'un polymère renforcé pour application automobile


    Klimkeit, Bert


    This thesis...; Cette thèse contribue à la compréhension du comportement en fatigue des thermoplastiques renforcés par des fibres de verre courtes. Deux différents matériaux sont étudiés : Un mélange de polybutylène téréphtalate et polyéthylène téréphtalate (PBT+PET GF30) et un polyamide 66 (PA66 GF35). Les enjeux scientifiques de la thèse concernent les chargements multiaxiaux, l'influence de la contrainte moyenne et l'orientation de fibres sur la tenue en fatigue. En outre, les mécanismes d...


    CERN Multimedia

    Solar Club


    Le club tiendra son Assemblée générale le mercredi 13 avril 2011 à la suite de la conférence organisée par l'Association du personnel Sur la route du soleil levant Une première en vélo électrique solaire qui a lieu à 18 h 30 * * * * * * L’AG aura donc lieu vers 20 h 15. Ordre du jour habituel avec comptes rendus des Activités et finances, et présentations des projets pour le futur. Rejoignez-nous pour parler du solaire et des énergies renouvelables en général, proposer des projets et y participer. L’AG se termine avec le verre de l'amitié !

  5. Liberté, Égalité, Ébriété

    Directory of Open Access Journals (Sweden)

    Geneviève Lafrance


    Full Text Available « Allons, enfants de la Courtille, le jour de boire est arrivé. » Fusil à l’épaule, chanson aux lèvres et verre à la main, les patriotes qui célébraient, fin 1792, l’avènement de la République entendaient jouir d’un privilège que la mise à sac de l’Ancien Régime avait laissé intact : celui qu’ont les vainqueurs de trinquer à leurs succès. En cet automne où l’on s’apprêtait à voter la mort du roi, un parodiste anonyme profita des circonstances pour offrir au lectorat parisien une version burle...

  6. Contribution to the analytic study of ferrates; Contribution a l'etude analytique des ferrates

    Energy Technology Data Exchange (ETDEWEB)

    Becarud, N. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires


    Preparation and chemical properties of potassium, strontium and barium ferrates are described. Separation by glass-paper chromatography, electrochemical studies and infrared spectra are shown. A polarographic determination of ferrate ion have been worked. The stability of these compounds is studied with differential thermal analysis. (author) [French] Ce travail concerne la preparation de divers ferrates ainsi que la recherche de leurs proprietes chimiques. On a etudie les moyens specifiques de les detecter, leur chromatographie sur papier a fibre de verre et leurs proprietes electrochimiques. Une methode de dosage polarographique des ferrates est decrite. Les spectres d'absorption infra-rouge sont fournis. Enfin on a etudie leur decomposition par analyse thermique differentielle. (auteur)

  7. Italian comics and cinema: forms and functions of pornographic parody

    Directory of Open Access Journals (Sweden)

    Mauro Giori


    Full Text Available Il saggio si propone di indagare un fenomeno come il frequente ricorso alla parodia di testi preesistenti da parte della pornografia, un fenomeno tanto notorio quanto trascurato, anche dalla recente ondata di studi su questo particolare genere. Al centro dell’indagine viene posta una forma di pornografia che in Italia, tra gli anni ’60 e gli anni ’80, ha fatto da testa di ponte alla diffusione di quella cinematografica attraverso una produzione industriale vasta quanto peculiare: quella in forma di fumetto. Tale produzione verrà analizzata in una prospettiva intermediale, ovvero nelle sue molteplici relazioni con il mondo del cinema, che vanno dall’assegnazione di volti di attori celebri ad alcuni eroi delle sue serie fino alla vera e propria parodia di interi film. Si mettono così in luce caratteri e funzioni assolti dalla parodia nell’ambito specifico della pornografia.

  8. 'Paranoia and its historical development (systematized delusion)', by Eugenio Tanzi (1884). (United States)

    Castagnini, Augusto


    This was the first paper by the Italian alienist Eugenio Tanzi (1856-1934). It surveyed existing works and provided an analysis of clinical categories such as monomania, sensory madness, moral insanity, Wahnsinn, Verrücktheit and systematized delusions, which had been used in France, Germany, Britain and Italy since the early nineteenth century to deal with paranoia. As pointed out by Tanzi, discrepancies and discontinuities in diagnostic concepts affected both psychiatric nosology and practice. Paranoia (from the Greek παρά and νοια) made for greater clarity in psychiatric terminology, and denoted a broad category, including both acute and chronic delusional states which were considered to be distinct from mania and melancholia, and usually not to lead to mental deterioration. © The Author(s) 2016.

  9. Hahn AB, Hunsbruck, Germany. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F (United States)


    FREQUENCY OF WIND t- DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 34055 HAHN A2-I--iP:S LJCk VERr’.IY w.-77 _Ec STATMl STWATOI ILt YEARS -LL ,.- Td ...iFROM HOURLY OBSERVATIONS; % 0ly JE,", 2v 1 . ’. 22.7 i. 41.3 .. 4 2,.7 Z . 3 5. 73 ’ 1 t . t ’ . . _ -_. -,21 . 2 L" . 41d- -. c. - - - -’ 2 .1 19.7 c...8217;-12 13- 14 15. 16 - 1819 - 20 21 -2223- 2425-26 27-28129 .30 31 D.B.M.B.7,, B. We, B tD . P.. 76/ 75 L .4i 73 72/ 71 o 1 4L i 70/ ,9 . 1 .1. 2 2 68i

  10. Génération de seconde harmonique d'un laser bi-fréquence à 1,55 μm accordable sur plusieurs THz dans un cristal composite à quasi-accord de phase (United States)

    Lai, N. D.; Brunel, M.


    Nous étudions les propriétés d'un cristal de niobate de lithium à polarisation périodique (PPLN) à deux sections, l'une dont la période de retournement est fixe, et l'autre en éventail. Un modèle simple de quasi-accord de phase permet de calculer les périodes pour les deux sections, ainsi que les acceptances spectrale, thermique et spatiale. En utilisant un laser Er-Yb:verre bi-axe émettant deux ondes de fréquences accordables autour de 1,55 μm, nous obtenons une source bi-fréquence à 775 nm avec une différence de fréquence continûment accordable de 0 à 4,2 THz.

  11. Dorures des céramiques et tesselles anciennes : technologies et accrochage


    Colomban, Philippe; Calligaro, Thomas; Vibert-Guigue, Claude; Nguyen, Quang Liem; Edwards, Howell G.M.


    Les technologies de dorures des céramiques et verres et leurs évolutions historiques sont très mal documentées. Des échantillons d'époques et de technologies différentes (tesselles d'époque omeyyade, début VIIIe s., Qusayr 'Amra, Jordanie ; porcelaine de type « Kinran-de », épave de Cu Lao Cham, XVe s. Vietnam ; porcelaine phosphatique de Rockingham, début XIXe s., Angleterre) ont été analysés par PIXE et RBS sur l'accélérateur AGLAE et par micro-spectrométrie Raman. Dans tous ces cas, l'or e...

  12. Pluridisciplinaire

    Directory of Open Access Journals (Sweden)

    Eliana Magnani


    Full Text Available L’actualité de la recherche présentée dans ce onzième volume du Bulletin du CEM montre le renforcement pluridisciplinaire dans la plupart des programmes de recherche menés par les médiévistes de l’ARTeHIS (UMR 5594 – archéologues, historiens, historiens de l’art et musicologues – regroupés autour du Centre d’études médiévales d’Auxerre. L’analyse et l’étude des matériaux, du verre aux terres cuites architecturales, en passant par les pierres, les enduits et le stuc, sont depuis plusieurs ann...

  13. The Air Is on Fire

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    Thérèse Guilbert


    Full Text Available C’est un grand néon rose fluorescent accroché à la façade de verre de la Fondation Cartier qui affiche le nom de David Lynch et annonce l’exposition The Air Is on Fire (du 3 mars au 27 mai 2007. La forme froide des lettres intriquées évoque l’architecture industrielle qui fascine tant l’artiste et, sans surprise, le modèle du néon sera à chercher dans la collection de ses dessins soigneux. Car on connaissait David Lynch le cinéaste, mais voilà le plasticien : peintures et aquarelles, sculptu...

  14. Sammenhengen mellom livserfaringer og utvikling av langvarige muskelplager og fibromyalgi; en fenomenologisk livsverdenstudie av 5 kvinners livserfaringer i årene før de fikk diagnosen fibromyalgi

    Directory of Open Access Journals (Sweden)

    Anne Kristin Wanvik


    Resultater; En sterk andreorientering og smerter og trøtthet i kroppen og lange perioder med fysisk og psykisk stress i årene før de fikk diagnosen fibromyalgi. Plagene ble forsøkt skjøvet bort og ignorert og symptomene ble verre med årene. En opplevelse av kroppen som noe annet enn ”dem selv”. Konklusjon; Kvinner som utvikler fibromyalgi viser i denne studien en splittelse mellom kroppen og selvet, og at kroppen ofte oppleves som et objekt.  Dette kan sees som en manglende identifisering med og en objektgjøring av egen kropp.  Denne fremmedgjøringen og objektgjøringen av egen kropp synes å ha vært medvirkende til overbelastning av kroppen og utvikling av langvarige muskelplager for kvinnene i studien.

  15. El retorno inmanente del lenguaje: Impressions d’Afrique de Raymond Roussel y sus influencias en la obra de Marcel Duchamp

    Directory of Open Access Journals (Sweden)

    Pedro Alberto Cruz Sánchez


    Full Text Available La presencia de Marcel Duchamp en una de las representaciones de Impressions d’Afrique de Raymond Roussel en el Théâtre Antoine, de París, en mayo de 1912, constituye uno de los hitos ineludibles a la hora de estudiar la vida y obra del autor del Grand Verre. El objetivo de este artículo es ampliar el estrecho marco de reflexión en el que usualmente se abordan las conexiones entre ambas figuras de la vanguardia europea, y encontrar reflejos del célebre procédé de Roussel en la obra de Duchamp. Para ello se priorizarán aspectos clave dentro de la construcción de Impressions d’Afrique como su estructura bipartita, la homofonía y la materialidad del signo lingüístico.

  16. Your World in Pictures

    Directory of Open Access Journals (Sweden)

    Frédéric Perrier


    Full Text Available En association avec le groupe Time Inc., propriétaire de Life Magazine, dont la version papier a disparu des kiosques en 2007 du fait de son coût d’impression devenu trop lourd, le géant américain Google a mis en ligne une partie de la collection du magazine. Photographies, gravures, plaques de verre et diapositives (dont la grande majorité n’a jamais été publiée sont archivées sur un site qui leur sont dédiées: Google Images. Elles sont disponibles gratuitement pour un usage personnel ou po...

  17. Gallé, une vie au tournant du siècle.

    Directory of Open Access Journals (Sweden)

    Isabelle Debilly


    Full Text Available La collection Découvertes de Gallimard propose un nouveau volume dédié à Émile Gallé, le magicien du verre . Il s’agit là déjà, du 446 e numéro de cette collection destinée à l’origine aux adolescents. Ce principe a été en grande partie abandonné, même si l’on trouve encore les volumes de cette collection dans les rayons « jeunesse » de certaines librairies. Le grand public a depuis longtemps plébiscité ces ouvrages qui présentent une riche iconographie, ...

  18. L’Apprentissage inutile : roman actuel

    Directory of Open Access Journals (Sweden)

    Joël Goffin


    Full Text Available David Scheinert (1916-1996 est né à Częstochowa, la ville de la Vierge noire où affluent les pèlerins des quatre coins de la Pologne. Ses parents étaient des négociants et des souffleurs de verre, métiers qui assuraient une relative prospérité à la famille. Lorsque David eut huit ans, sa famille s’installa à Bruxelles, dans un univers qui leur était complètement inconnu. Très vite, l’enfant, à l’intelligence vive et brillante, montra une grande aptitude d’intégration. Mais il serait faux de ...

  19. Tracer sa route, en toute intransparence numérique ?

    Directory of Open Access Journals (Sweden)

    Philippe Vidal


    Full Text Available « Comme l’intransparence des vitres ferait tache dans une habitation et l’attristerait en obstruant le passage du regard, on a dû chercher au moyen de voir au travers sans être vu, et l’on a inventé le verre mousseline. » L’expression « tracer sa route » est souvent utilisée dans un sens familier. Elle signifie, ordinairement, partir à l’aventure, sans se soucier des éventuelles contraintes et conséquences d’un tel choix, qu’elles soient sociales, matérielles ou familiales. A l’image des trav...

  20. Honoré de Balzac : une autre image


    Derville, Nicolas


    "Quels qu'ils soient, privés ou publics, confidentiels ou officiels, rares sont les portraits de Balzac qui ne recèlent pas une énigme. Comme s'il avait organisé le mystère autour d'eux, comme s'il n'avait cessé de fomenter un complot propre à nous perdre dans le labyrinthe de ses "cent moi-même"." Le portrait présumé de Balzac que nous publions ici (fig. 1. P.-A. Richebourg, portrait présumé d'Honoré de Balzac, papier salé d'après négatif verre au collodion, 197 x 148 mm, v. 1853, cop...

  1. Prise en compte du vieillissement et de l'endommagement dans le dimensionnement de structures en matériaux composites


    Mercier, Julien


    La présente étude traite de la durabilité (vieillissement) en milieu humide et de l'endommagement par fissuration de matériaux composites à matrice organique (CMO).La diffusion d'eau dans le matériau (matrice époxy renforcée par des fibres de verre) est tout d'abord analysée expérimentalement par détermination des cinétiques d'absorption sous différentes conditions d'humidité. Des baisses de différentes propriétés mécaniques en fonction de la quantité d'eau absorbée sont mises en évidence et ...

  2. La trasformazione dell’esperienza. Antropologia e processi di cura

    Directory of Open Access Journals (Sweden)

    Ivo Quaranta


    Full Text Available Abstract – IT Sulla base di un approccio antropologico, l’incontro terapeutico verrà ripensato come un processo di produzione partecipativa del significato della realtà, capace di promuovere una rielaborazione dell’esperienza di malattia, consentendo inoltre l’individuazione di possibili forme di intervento capaci di generare socialmente tale trasformazione. Introducendo il concetto di “diritto al significato” come terreno per l’individuazione di quali altri diritti promuovere, il concetto di efficacia terapeutica verrà ripensato in termini di trasformazione: non solo nei termini delle possibili trasformazioni sul piano anatomico-fisiologico che le tecniche di intervento biomedico possono realizzare; non solo nei termini delle trasformazioni nei rapporti di senso che la relazione di cura incentrata sul diritto al significato può promuovere; ma anche nei termini di una trasformazione dei rapporti sociali in cui i pazienti sono coinvolti.  Abstract – EN In anthropological terms the therapeutic encounter will be reconsidered as a process of participatory production of the meaning, promoting a reformulation of the experience of illness and allowing the identification of possible forms of intervention capable of socially generating such a reformulation. The concept of “right to meaning” as a basis for the identification of other rights helps us to reframe the issue of therapeutic efficacy. The latter will be reconsidered through the concept of transformation, not only in terms of the possible transformations on the anatomo-physiological plane that can be performed by biomedical intervention, or in terms of the changes in the relationships of meaning that the right to meaning can promote, but also in terms of a transformation in the patients’ social relationships.

  3. Understanding of the mechanical and structural changes induced by alpha particles and heavy ions in the French simulated nuclear waste glass (United States)

    Karakurt, G.; Abdelouas, A.; Guin, J.-P.; Nivard, M.; Sauvage, T.; Paris, M.; Bardeau, J.-F.


    Borosilicate glasses are considered for the long-term confinement of high-level nuclear wastes. External irradiations with 1 MeV He+ ions and 7 MeV Au5+ ions were performed to simulate effects produced by alpha particles and by recoil nuclei in the simulated SON68 nuclear waste glass. To better understand the structural modifications, irradiations were also carried out on a 6-oxides borosilicate glass, a simplified version of the SON68 glass (ISG glass). The mechanical and macroscopic properties of the glasses were studied as function of the deposited electronic and nuclear energies. Alpha particles and gold ions induced a volume change up to -0.7% and -2.7%, respectively, depending on the glass composition. Nano-indentations tests were used to determine the mechanical properties of the irradiated glasses. A decrease of about -22% to -38% of the hardness and a decrease of the reduced Young's modulus by -8% were measured after irradiations. The evolution of the glass structure was studied by Raman spectroscopy, and also 11B and 27Al Nuclear Magnetic Resonance (MAS-NMR) on a 20 MeV Kr irradiated ISG glass powder. A decrease of the silica network connectivity after irradiation with alpha particles and gold ions is deduced from the structural changes observations. NMR spectra revealed a partial conversion of BO4 to BO3 units but also a formation of AlO5 and AlO6 species after irradiation with Kr ions. The relationships between the mechanical and structural changes are also discussed.

  4. Effect of natural and synthetic iron corrosion products on silicate glass alteration processes (United States)

    Dillmann, Philippe; Gin, Stéphane; Neff, Delphine; Gentaz, Lucile; Rebiscoul, Diane


    Glass long term alteration in the context of high-level radioactive waste (HLW) storage is influenced by near-field materials and environmental context. As previous studies have shown, the extent of glass alteration is strongly related to the presence of iron in the system, mainly provided by the steel overpack around surrounding the HLW glass package. A key to understanding what will happen to the glass-borne elements in the geological disposal lies in the relationship between the iron-bearing phases and the glass alteration products formed. In this study, we focus on the influence of the formation conditions (synthetized or in-situ) and the age of different iron corrosion products on SON68 glass alteration. Corrosion products obtained from archaeological iron artifacts are considered here to be true analogues of the corrosion products in a waste disposal system due to the similarities in formation conditions and physical properties. These representative corrosion products (RCP) are used in the experiment along with synthetized iron anoxic corrosion products and pristine metallic iron. The model-cracks of SON68 glass were altered in cell reactors, with one of the different iron-sources inserted in the crack each time. The study was successful in reproducing most of the processes observed in the long term archaeological system. Between the different systems, alteration variations were noted both in nature and intensity, confirming the influence of the iron-source on glass alteration. Results seem to point to a lesser effect of long term iron corrosion products (RCP) on the glass alteration than that of the more recent products (SCP), both in terms of general glass alteration and of iron transport.

  5. Low-temperature lithium diffusion in simulated high-level boroaluminosilicate nuclear waste glasses

    Energy Technology Data Exchange (ETDEWEB)

    Neeway, James J.; Kerisit, Sebastien N.; Gin, Stephane; Wang, Zhaoying; Zhu, Zihua; Ryan, Joseph V.


    Ion exchange is recognized as an integral, if underrepresented, mechanism influencing glass corrosion. However, due to the formation of various alteration layers in the presence of water, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other processes occurring simultaneously during corrosion. In this work, an operationally inert non-aqueous solution was used as an alkali source material to isolate ion exchange and study the solid-state diffusion of lithium. Specifically, the experiments involved contacting glass coupons relevant to the immobilization of high-level nuclear waste, SON68 and CJ-6, which contained Li in natural isotope abundance, with a non-aqueous solution of 6LiCl dissolved in dimethyl sulfoxide at 90 °C for various time periods. The depth profiles of major elements in the glass coupons were measured using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Lithium interdiffusion coefficients, DLi, were then calculated based on the measured depth profiles. The results indicate that the penetration of 6Li is rapid in both glasses with the simplified CJ-6 glass (D6Li ≈ 4.0-8.0 × 10-21 m2/s) exhibiting faster exchange than the more complex SON68 glass (DLi ≈ 2.0-4.0 × 10-21 m2/s). Additionally, sodium ions present in the glass were observed to participate in ion exchange reactions; however, different diffusion coefficients were necessary to fit the diffusion profiles of the two alkali ions. Implications of the diffusion coefficients obtained in the absence of alteration layers to the long-term performance of nuclear waste glasses in a geological repository system are also discussed.

  6. Single Silver Adatoms on Nanostructured Manganese Oxide Surfaces: Boosting Oxygen Activation for Benzene Abatement. (United States)

    Chen, Yaxin; Huang, Zhiwei; Zhou, Meijuan; Ma, Zhen; Chen, Jianmin; Tang, Xingfu


    The involvement of a great amount of active oxygen species is a crucial requirement for catalytic oxidation of benzene, because complete mineralization of one benzene molecule needs 15 oxygen atoms. Here, we disperse single silver adatoms on nanostructured hollandite manganese oxide (HMO) surfaces by using a thermal diffusion method. The single-atom silver catalyst (Ag1/HMO) shows high catalytic activity in benzene oxidation, and 100% conversion is achieved at 220 °C at a high space velocity of 23 000 h(-1). The Mars-van Krevelen mechanism is valid in our case as the reaction orders for both benzene and O2 approach one, according to reaction kinetics data. Data from H2 temperature-programmed reduction and O core-level X-ray photoelectron spectra (XPS) reveal that Ag1/HMO possesses a great amount of active surface lattice oxygen available for benzene oxidation. Valence-band XPS and density functional theoretical calculations demonstrate that the single Ag adatoms have the upshifted 4d orbitals, thus facilitating the activation of gaseous oxygen. Therefore, the excellent activation abilities of Ag1/HMO toward both surface lattice oxygen and gaseous oxygen account for its high catalytic activity in benzene oxidation. This work may assist with the rational design of efficient metal-oxide catalysts for the abatement of volatile organic compounds such as benzene.

  7. Effect of Sulfur Concentration and PH Conditions on Akaganeite Formation: Understanding Akaganeite Formation Conditions in Yellowknife Bay, Gale Crater, Mars (United States)

    Fox, A.; Peretyazhko, T.; Sutter, B.; Niles, P.; Ming, D. W.; Morris, R. V.


    The Chemistry and Mineralogy Instrument (CHEMIN) on board the Mars Science Laboratory (MSL) Curiosity Rover identified minor amounts of akaganeite (beta-FeOOH) at Yellowknife Bay, Mars. There is also evidence for akaganeite at other localities on Mars from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Akaganeite is an iron(III) hydroxide with a hollandite- like structure and Cl in its tunnels. Terrestrial akaganeite usually forms in Cl-rich environments under acidic, oxidizing conditions. Previous studies of akaganeite have revealed that akaganeite formation is affected by the presence of sulfate (hereafter denoted as S. The prediction of circumneutral pH coupled with the detection of S at Yellowknife Bay dictate that work is needed to determine how S and pH together affect akaganeite formation. The goal of this work is to study how changes in both S concentration and pH influence akaganeite precipitation. Akaganeite formation was investigated at S/Cl molar ratios of 0, 0.017, 0.083, 0.17 and 0.33 at pH 1.5, 2, and 4. Results are anticipated to provide combined S concentration and pH constraints on akaganeite formation in Yellowknife Bay and elsewhere on Mars. Knowledge of solution pH and S concentrations can be utilized in understanding microbial habitability potential on the Martian surface.

  8. Status of plutonium ceramic immobilization processes and immobilization forms

    Energy Technology Data Exchange (ETDEWEB)

    Ebbinghaus, B.B.; Van Konynenburg, R.A. [Lawrence Livermore National Lab., CA (United States); Vance, E.R.; Jostsons, A. [Australian Nuclear Science and Technology Organization, Menai (Australia)] [and others


    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R&D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi{sub 2}O{sub 7}), the desired actinide host phase, with lesser amounts of hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). Alternative actinide host phases are also being considered. These include pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}), zircon (ZrSiO{sub 4}), and monazite (CePO{sub 4}), to name a few of the most promising. R&D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO{sub 2} powder, cold press and sinter fabrication methods, and immobilization form formulation issues.

  9. Adsorption of Lanthanides by A{sub y}Mo{sub x}W{sub 1-x}O{sub 3} Hexagonal Tungsten Bronzes and Prospects for their Potential Use as Recyclable Inert Matrix Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Luca, Vittorio; Yang, Bin; Yaman, Ilkay; Griffith, Christopher S.; Scales, Nicholas; Sizgek, Erden [Australian Nuclear Science and Technology Organisation (ANSTO), Institute of Materials Engineering, New Illawarra Road, Lucas Heights, New South Wales, 2234 (Australia)


    The hexagonal tungsten bronze (HTB) based adsorbents of general formula A{sub y}M{sub x}W{sub 1-x}O{sub 3}.ZH{sub 2}O have been a particular focus of attention in our laboratory for some time. In the context of a potential partition and transmutation strategy our interest in these HTB materials has been stimulated by their particularly high affinity for lanthanide (LN) and minor actinide (MA). In addition to partitioning operations the materials can also be contemplated for mop-up and decontamination applications. With Cs{sup +} as the target species, HTBs can be converted to very effective waste form materials with performances comparable to the best Cs-containing ceramics such as hollandite. However, their excellent affinity for LNs and MAs suggest their use for MA recycling. When granular variants of the HTB adsorbents are loaded with LNs and are heated in air to relatively modest temperatures these elements preferentially partition into relatively soluble phases imbedded within a durable WO{sub 3} matrix. Since the LN-containing phase is relatively soluble, efficient recovery of the LNs or potentially MAs is feasible. This, together with potentially favorable irradiation properties, suggests they may have uses as recyclable inert matrix fuels. In this communication, we discuss LN and MA adsorption and thermal properties of HTB materials with variable x, as well as resistance to {gamma}-radiation and heavy ion bombardment. Finally, recoverability of the LNs is considered. (authors)

  10. Ultra-low thermal conductivity of TlIn5Se8 and structure of the new complex chalcogenide Tl0.98In13.12Se16.7Te2.3 (United States)

    Lefèvre, Robin; Berthebaud, David; Pérez, Olivier; Pelloquin, Denis; Boudin, Sophie; Gascoin, Franck


    TlIn5Se8 has been synthesized by means of solid-state reaction and densified by Spark Plasma Sintering. The compound is a semiconductor with a band gap of 1.62 eV estimated from reflectance measurements. Its thermal conductivity is about 0.45 W m-1. K-1 in the temperature range 300-673 K, an extremely low value attributed to its complex pseudo-1D structure reminiscent of the pseudo-hollandite. While attempting to dope TlIn5Se8 with Te, a new complex chalcogenide was discovered and characterized by the combination of TEM and XRD diffraction. It belongs to the A2In12X19 family, crystallizing in the R 3 ̅:H space group. Single crystal X-ray diffraction study led to a refined composition of Tl0.98In13.12Se16.7Te2.3 with cell parameters: a=13.839(5) Å and c=35.18(3) Å. A static disorder is found on one indium site situated in an octahedral environment. The single crystal XRD study is in agreement with TEM analyses in STEM-HAADF image mode that do not show any extended defects or disorder at atomic scale.

  11. Mineralogical aspects of Morro de Seis Lagos deposit (Amazonas, Brazil). (United States)

    Takehara, Lucy; Almeida, Marcelo; Silveira, Francisco


    The alkaline body Morro dos Seis Lagos, situated in the northwest Amazonian region, is a Nb bearing deposit formed by thick lateritic regolith as circular geological feature about 5 km in diameter. The host rock of this deposit is an intensely weathered siderite carbonatite. The alkaline intrusion body was formed during the late Mesozoic and enriched during the Cenozoic by process of denudation of the surrounding rocks and formation of lateritic cover with thickness in the order of hundreds of meters. In this process, enrichment of Nb, Fe, Ti, Mn, P and rare earth elements (REE) occurred where the lateritic regolith represents the major Nb mineralization, with estimated inferred reserves of 2.9 billion ton@ 2.8 % Nb2O5, one of the largest deposits of Nb in the world. The mineralogical composition of the lateritic regolith has the predominance of the goethite and hematite, followed by oxy - hydroxides of Mn, Ti - Nb oxides, pyrochlore, cerianite and phosphates. The lateritic regolith samples showed high contents of Fe2O3 40 %, and is followed by elevated Th concentration, which locally has concentration higher than (18%). Another REE mineral is the cerianite. The main manganese minerals are hollandite, romanechite (BaMn9O16[OH4] - mixtures of manganese oxides) and amorphous Mn oxy - hydroxides. The higher concentration of MnO2 (about 40 %) is restricted to manganesiferous range, where manganese minerals occur as layers and filling voids, indicating strong remobilization by later process.

  12. High-Pressure Phases in Shock-Induced Melt Veins from the Umbarger L6 Chondrite: Constraints on Shock Conditions (United States)

    Xie, Z.; Tomioka, N.; Sharp, T. G.


    Shock-induced melt veins in the Umbarger L6 (S6) chondrite contain a previously unknown set of high-pressure phases consisting of ringwoodite ((Mg, Fe)2SiO4), akimotoite ((Mg, Fe)SiO3-ilmenite), augite ((Ca, Na)(Mg, Fe, Al)(Si, Al)2O6), and hollandite-structured plagioclase ((Na, K, Ca)(Al, Si)4O8). Crystallization of akimotoite suggests supercooling of the melt vein during adiabatic decompression. High-pressure minerals are common in highly shocked (S6) L6 chondrites. These minerals, which occur within or adjacent to shock-induced melt veins, provide evidence of very high pressure and temperature conditions during impact events. The goal of this study is to characterize the high-pressure mineral assemblages of the melt veins in the L6 chondrite Umbarger to better understand crystallization conditions, and the shock history of meteorite parent body. Mineral assemblages in shock-induced melt veins have been used to estimate crystallization conditions during shock metamorphism. based on phase equilibrium data. Umbarger was previously classified as shock stage S4, based on deformation features not associated with melt veins. Based on previously unrecognized ringwoodite in the melt veins of Umbarger, we classified the shock stage as S6. Further transmission electron microscopy (TEM) study reveals several other high-pressure phases in melt veins that can be used to infer crystallization and shock conditions.

  13. Back-transformation of high-pressure phases in a shock melt vein of an H-chondrite during atmospheric passage: Implications for the survival of high-pressure phases after decompression (United States)

    Kimura, M.; Chen, M.; Yoshida, Y.; El Goresy, A.; Ohtani, E.


    We investigated the H6-chondrite Yamato 75267, in which a fusion crust cuts a shock melt vein. The shock vein region, more than 280 μm from the fusion crust, contains high-pressure phases, such as ringwoodite, majorite-pyrope ss garnet and NaAlSi 3O 8 hollandite. However, the shock vein close to the fusion crust entirely consists of the low-pressure polymorphs, olivine, low-Ca pyroxene and plagioclase glass. The boundary between low- and high-pressure phase regions is parallel to the fusion crust. During the atmospheric passage, the peripheral part of the chondrite was melted to form the fusion crust. Our microscopic, laser micro-Raman, electron microprobe investigations and calculations indicate an area up to 300 μm from the fusion crust experienced a temperature of 1400°C after 3 s during the melting of the peripheral part. The high-pressure phases would, at this conditions, quickly transform back to their low-pressure polymorphs. The result obtained here indicates that post-shock temperatures in the interior part of the veins were much lower than 1400°C, thus leading to the survival of high-pressure phases in heavily shocked chondrites.

  14. Formation of high-pressure minerals in shocked L6 chondrite Yamato 791384: constraints on shock conditions and parent body size (United States)

    Ohtani, Eiji; Kimura, Yukiko; Kimura, Makoto; Takata, Toshiko; Kondo, Tadashi; Kubo, Tomoaki


    We have studied the high-pressure phases observed in Yamato 791384 L6 chondrite. Host meteorite mainly consists of olivine, pyroxenes and plagioclase glass. Mineral fragments observed in the veins and the vein margin region of the host meteorite were partially or totally transformed into high-pressure phases; ringwoodite, majorite, akimotoite, NaAlSi 3O 8 hollandite and jadeite. Matrix of the shock vein contains majorite-pyrope solid solution. The spatial distribution indicates that high-pressure phases are present in the shock veins and host rocks adjacent to the shock veins. Investigation of the high-pressure phases revealed that, in Y791384, fragments and adjacent matrix were subjected to pressures around of 18-23 GPa and the vein experienced temperatures around 2300 °C during the shock event. Ringwoodite lamellae were observed in the host olivine adjacent to the vein. Kinetic investigation for ringwoodite lamellar growth in olivine indicates that the shocked meteorite experienced the pressure for at least 4 s. Such long duration of the pressure pulse indicates that the size of the parent body was greater than 10 km.

  15. Transformation textures, mechanisms of formation of high-pressure minerals in shock melt veins of L6 chondrites, and pressure-temperature conditions of the shock events (United States)

    Ozawa, S.; Ohtani, E.; Miyahara, M.; Suzuki, A.; Kimura, M.; Ito, Y.


    The high-pressure polymorphs of olivine, pyroxene, and plagioclase in or adjacent to shock melt veins (SMVs) in two L6 chondrites (Sahara 98222 and Yamato 74445) were investigated to clarify the related transformation mechanisms and to estimate the pressure-temperature conditions of the shock events. Wadsleyite and jadeite were identified in Sahara 98222. Wadsleyite, ringwoodite, majorite, akimotoite, jadeite, and lingunite (NaAlSi3O8-hollandite) were identified in Yamato 74445. Wadsleyite nucleated along the grain boundaries and fractures of original olivine. The nucleation and growth of ringwoodite occurred along the grain boundaries of original olivine, and as intracrystalline ringwoodite lamellae within original olivine. The nucleation and growth of majorite took place along the grain boundaries or fractures in original enstatite. Jadeite-containing assemblages have complicated textures containing “particle like,” “stringer-like,” and “polycrystalline-like” phases. Coexistence of lingunite and jadeite-containing assemblages shows a vein-like texture. We discuss these transformation mechanisms based on our textural observations and chemical composition analyses. The shock pressure and temperature conditions in the SMVs of these meteorites were also estimated based on the mineral assemblages in the SMVs and in comparison with static high-pressure experimental results as follows: 13-16 GPa, >1900 °C for Sahara 98222 and 17-24 GPa, >2100 °C for Yamato 74445.

  16. Divinacija prieš Cecilijų Cicerono retorikos kontekste. Divinatio in Caecilium in the context of Cicero’s rhetoric

    Directory of Open Access Journals (Sweden)

    Audronė Kučinskienė


    Full Text Available In the well known episode in the Divination against Caecilius (Divinatio in Caecilium 27–46, Cicero, assuming the role of a teacher, expounds issues of rhetoric to his opponent. In this article the following points are examined: 1 the relation of this episode to the theory of rhetoric of the time, as represented in the unknown author’s Rhetorica ad Herennium and Cicero’s De inventione, which he wrote as a young man; 2 the repercussions of this episode in Cicero’s later works of rhetoric; 3 the relation of this episode to the other speeches against Verres.In Div. Caec. 27–46, Cicero does not try to set forth his material systematically and sequentially, as it is customary in rhetorical treatises, but directs his attention first at the moral qualities of a good orator, as well as on his education and the innate personal traits that form a perfect orator. This allows us to connect the Divination against Caecilius with Cicero’s later treatises on rhetoric, in particular De oratore. Being a supporter of philosophical rhetoric, Cicero disdains the traditional Hellenistic manuals that expound rhetorical technique. He does not try to teach these things – which would be the aim of a rhetoric manual – but he presumes that his audience would understand them from the small hints about the topics that must be recognised as coming from the school of rhetoric. Such a stance corresponds well to the spirit of the treatise De oratore: in that work, Cicero does not teach rules and does not explain rhetorical technique either, but, having mastered these things perfectly himself, he addresses his work to those readers who know the art of rhetoric and who would certainly recognise and appreciate the hints on the art of rhetoric, which are scattered through the text rather than explicitly demonstrated.In the episode Div. Caec. 27–46, Cicero uses va­rious rhetorical figures copiously and inventively. It is obvious that, in explaining the issues of

  17. Efficacité du renforcement des poutres en béton armé par des matériaux composites Efficiency of strengthening concrete beams using FRP

    Directory of Open Access Journals (Sweden)

    Chemrouk M


    Full Text Available Pour réduire le coût et assurer un comportement relativement plus ductile pour des éléments en béton armés renforcés, l’addition des fibres de verre pourrait être considérée comme solution de rechange, puisqu’elles sont relativement plus déformables et meilleur marché que la fibre de carbone. Dans ce sens, le travail actuel vise à évaluer l’efficacité du renfort externe sur les poutres renforcées par le tissu de FRP (verre-carbone. Un total de sept poutres en béton armé a été renforcé en flexion et en cisaillement, et testé sous un chargement quatre points cyclique statique. Les champs des contraintes et de déformation ont été contrôlés par un système de caméra numérique “Gom-Aramis”. Les résultats ont été analysés en termes de résistance, rigidité, ductilité et mode de rupture. To reduce the cost and to ensure a behavior relatively more ductile for concrete strengthening elements, the addition of glass fibers could be regarded as solution of replacement, since they are relatively more deformable and cheaper than carbon fiber. In this sense, current work aims at evaluating the effectiveness of the external reinforcement on the beams strengthened by fabric of FRP (glass – carbon. Seven concrete beams reinforced were strengthening in bending and shearing, and were testing under four point cyclic static. The fields of the stresses and deformation were controlled by a numerical system of camera “Gom-Aramis”. The results were analyzing in term of resistance, rigidity, ductility and mode of failure

  18. Marcel Duchamp, Constantin Brancusi, Victor Brauner : leurs rencontres et les retombées sur leurs œuvres

    Directory of Open Access Journals (Sweden)

    Cristian-Robert Velescu


    Full Text Available Duchamp avait rencontré Brancusi en 1912, année qui marque le début d’une amitié consignée par l’histoire de l’art. Son parcours avait été fixé dans les pages de leur correspondance, conservées au Centre Georges Pompidou. Le lecteur est surpris de constater qu’il n’y a que des faits anodins qui soient consignés, tandis que les références aux conceptions artistiques sont presque totalement absentes. Toutefois, en lisant les témoignages de Duchamp conservés dans les célèbres Boîtes (verte et blanche, on se rend compte qu’il partage les conceptions platoniciennes de son ami sculpteur, chose importante, qui nous laisse formuler des suppositions concernant une influence dirigée de Brancusi dans la direction Duchamp. À son tour, durant l’intervalle 1925–1928, Victor Brauner était l’hôte de Brancusi dans l’atelier de l’impasse Ronsin. C’est ici qu’il a pu rencontrer Duchamp, qui s’y rendait fréquemment dans les années 20. Une rencontre qui a certainement eu des retombées sur l’oeuvre du futur peintre surréaliste. La preuve en est dans deux de ses toiles, Tête et deux boxeurs et Passivité courtoise. Faut-il s’étonner que le message que Duchamp avait mis dans les structures sémantiques de son chef-d’oeuvre La Mariée mise à nu par ses célibataires, même ou Le Grand Verre y avait été « logé » d’une manière évidente ? Mais alors on doit reconnaître que lors de leurs rencontres de chez Brancusi, Duchamp avait transmis à Brauner des informations très précises sur l’iconographie du Grand Verre, ainsi que sur la quatrième dimension, que le futur peintre surréaliste allait reconvertir dans les trois dimensions de l’espace ordinaire. Perçu dans cette perspective, l’atelier de l’impasse Ronsin nous semble un lieu où les idées des trois artistes ont pu communiquer d’une manière osmotique.

  19. L’arcipelago postmoderno. Oreste del Buono e gli anni Settanta

    Directory of Open Access Journals (Sweden)

    Andrea Chiurato


    Il tentativo di cooptazione postuma tra le file dei simpatizzanti da parte del Gruppo 63 avrà breve fortuna (verrà incluso nella prima antologia del gruppo, ma non nelle se-guenti, e Renato Barilli arriverà addirittura a porlo a capo di un improbabile «Polo Bu-tor» (Chiurato 14, uno sparuto gruppo di „infiltrati‟ (insieme a Raffaele La Capria, Emilio Tadini, e Giuliano Gramigna nelle file della compagine neoavanguardista. Quarant‟anni dopo la questione rimane aperta e l‟eredità di quel turbolento periodo è ancora oggetto di discussione. La nostra intenzione è proporre un approccio diverso, che cer-chi di restituire la fluidità e la ricchezza delle suggestioni di allora poi irrigiditesi in cate-gorie critiche spesso frutto di semplificazioni indebite. Del Buono, irriducibile outsider, ci permette così di riscoprire gli anni Settanta da un‟angolazione inedita e di colmare, nello stesso tempo, alcune improvvide lacune nella nostra memoria culturale

  20. Architectural Kansei of ‘Wall’ in The Façade Design by Le Corbusier (United States)

    Sendai, Shoichiro

    The purpose of this paper is to discuss the modern architect Le Corbusier's architectural Kansei (sensibility) on wall in site environment through the analysis of his façade design, using Œuvres complètes (1910-1965, 8 vols., Les éditions d'architecture, Artemis, Zurich) and Le Corbusier Archives (1982-1984, 32 vols., Garland Publishing, Inc. and Fondation Le Corbusier, New York, London, Paris). At first, I arrange five façade types, according to the explanation by Le Corbusier ; ‘fenêtre en longueur (strip window)’, ‘pan de verre (glass wall)’, ‘brise-soleil (sun-breaker)’, ‘loggia’ and ‘claustra’. Through the analysis of the relationship between these types and the design process of each building, we find that Le Corbusier's façade design includes the affirmation and the negation of the ‘wall’ at the same time. In fact, the nature of façade modification during design process is divers: increase in transparency, decrease in transparency and spatialization of façade. That means, Le Corbusier studied the environmental condition by these façade types, and tried to realize the phenomenal openness. This trial bases on the function of architectural Kansei as correspondence between body and environment beyond the physical design.

  1. Multi-Agent System Fault Protection with Topology Identification in Microgrids

    Directory of Open Access Journals (Sweden)

    Stephanus Antonius Ananda


    Full Text Available Data acquisition and supervisory control are usually performed using client-server architecture and centralized control in conventional power systems. However, the message transmission and fault clearing are too slow for large-scale complex power systems. Microgrid systems have various types of distributed energy resources (DERs which are quite different in characteristics and capacities, thus, the client-server architecture and centralized control are inadequate to control and operate in microgrids. Based on MATLAB/Simulink (ver.R2012a simulation software and Java Agent Development Framework (JADE (JADE 4.1.1-revision 6532, this paper proposes a novel fault protection technology that used multi-agent system (MAS to perform fault detection, fault isolation and service restoration in microgrids. A new topology identification method using the YBus Matrix Algorithm is presented to successfully recognize the network configurations. The identification technology can respond to microgrid variations. Furthermore, the interactive communications among intelligent electronic devices (IEDs, circuit breakers (CBs, and agents are clarified during fault occurrence. The simulation results show that the proposed MAS-based microgrids can promptly isolate faults and protect the system against faults in real time.

  2. Immagini dietro le sbarre: l’utilizzo della fotografia per lo sviluppo dell’intelligenza emotiva dei detenuti

    Directory of Open Access Journals (Sweden)

    Emanuela Saita


    Full Text Available Nel presente contributo verrà descritto un intervento che utilizza tecniche fotografiche in attività trattamentali rivolte a soggetti in condizione di detenzione, attività le cui finalità sono la risocializzazione e la rieducazione del reo. Scopo dell'intervento è favorire lo sviluppo dell'intelligenza emotiva (IE, intesa come la capacità di comprendere e riconoscere i propri e gli altrui stati emotivi; essa infatti è associata in letteratura ad una riduzione della recidiva e ad un aumentato benessere dei soggetti reclusi. Le tecniche fotografiche costituiscono uno strumento in grado di superare barriere linguistico-culturali ed eventuali resistenze individuali per far emergere contenuti simbolici connessi a stati emotivi, credenze o percezioni. L'intervento descritto prevede incontri di gruppo, una tipologia di setting che diviene possibile strumento di apprendimento, riflessione sul sé, oltre che luogo di confronto e possibile cambiamento. La struttura degli incontri è tale da perseguire sia l'obiettivo generale (sviluppo dell'IE che obiettivi più specifici, calibrati su differenti categorie di detenuti. Ad esempio, favorire il reinserimento dopo la detenzione in caso di pene medio/brevi, piuttosto che l’accettazione della pena e l’adattamento alla vita carceraria, nel caso di pene più lunghe. Il contributo si chiude con un’apertura sulle possibili modalità di valutazione di tale intervento, al fine di giungere alla formulazione di un protocollo generalizzabile e applicabile a differenti contesti.

  3. Geneva University

    CERN Multimedia


    École de physique - Département de physique nucléaire et corpusculaire 24, quai Ernest-Ansermet 1211 GENÈVE 4 Tél: (022) 379 62 73 - Fax: (022) 379 69 92 Lundi 6 avril 2009 PARTICLE PHYSICS SEMINAR àt 17:00 – Auditoire Stückelberg Hospital superbugs, nanomechanics and statistical physics Prof. Dr G. Aeppli / University College London The alarming growth of the antibiotic-resistant superbug, methicillin-resistant Staphylococcus aureus (MRSA) is driving the development of new technologies to investigate antibiotics and their modes of action. We report silicon cantilever based studies of self-assembled monolayers of mucopeptides which model drug-sensitive and resistant bacterial walls. The underlying concepts needed to understand the measurements will simplify the design of cantilevers and coatings for biosensing and could even impact our understanding of drug action on bacteria themselves. (Une verrée en compagnie du conférencier sera offerte après le colloque.) Organizer : Prof. Markus Büttiker ...

  4. Inclusive learning plans using ict: the Aessedi project

    Directory of Open Access Journals (Sweden)

    Vincenza Benigno


    Full Text Available Il contesto educativo è uno dei principali luoghi per prevenire l’esclusione sociale e per garantire delle opportunità di partecipazione attiva in tutti gli ambiti della vita per tutti i soggetti con bisogni speciali. La scuola e in generale i sistemi deputati all’istruzione hanno come obiettivo principale promuovere la partecipazione di tutti i soggetti ai processi di apprendimento e acquisizione di competenze. Nell’ambito di questo lavoro verrà presentato uno studio pilota finalizzato all’ideazione e sperimentazione in classe di percorsi di apprendimento basati sull’uso di tecnologie multimediali realizzati in una logica di completa inclusione dei soggetti con bisogni speciali. I percorsi didattici sono frutto della progettazione collaborativa di più docenti sia curricolari che di sostegno. La progettazione è stata supportata da un ambiente web-based, AESSEDI, che ha costituito una sorta di itinerario per i docenti che, attraverso una serie di indicatori, hanno potuto riflettere sulle questioni legate all’inclusione.

  5. Itinerari Musicali con la Wiild

    Directory of Open Access Journals (Sweden)

    Elisabetta Nanni


    Full Text Available La Wiild, acronimo di Wiimote Lavagna Digitale, è uno strumento didattico che utilizza il telecomando della Wii, il famoso gioco della Nintendo, insieme a un software libero, rendendolo così estremamente versatile. Non vincolato a software proprietario, il suo utilizzo è legato alla capacità dell’insegnante di ripartire dalla didattica, dalle risorse selezionate e dall’epistemologia di ogni singola disciplina, trovando così nel proprio contesto un ruolo per le tecnologie. Il contributo presenta ipotesi di lavoro per l’educazione musicale nella scuola secondaria di primo grado che si sviluppano sia attraverso lo studio del rapporto suono/segno con affinità pittoriche e successiva codificazione grafica, sia attraverso un’attività di laboratorio in cui co-costruire percorsi storico-musicali. La Wiild diventerà davvero utile ed efficace nel momento in cui, affiancando le risorse selezionate dal docente, verrà utilizzata senza essere notata, giocando un ruolo di strumento tecnologico «normale e trasparente».

  6. An experimental propane bubble chamber; Sur une chambre a bulles experimentale a propane

    Energy Technology Data Exchange (ETDEWEB)

    Rogozinski, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Describes a propane bubble chamber 10 cm in diameter and 5 cm deep. The body of the chamber is in stainless steel, and it has two windows of polished hardened glass. The compression and decompression of the propane are performed either through a piston in direct contact with the liquid, or by the action on the liquid, through a triple-mylar-Perbunan membrane, of a compressed gas. The general and also optimum working conditions of the chamber are described, and a few results are given concerning, in particular, the tests of the breakage-resistance of the windows and the measurements of the thermal expansion of the compressibility isotherm for the propane employed. (author) [French] Description d'une chambre a bulles a propane de 10 cm de diametre et de 5 cm de profondeur. La chambre, dont le corps est en acier inoxydable, est munie de deux fenetres en verre poli et trempe. La compression et la detente du propane sont effectuees, soit a l'aide d'un piston en contact direct avec le liquide, soit en faisant agir sur ce dernier un gaz comprime a travers une triple membrane de teflon-mylar-perbunan. On decrit les conditions generales, ainsi que les conditions optimales de fonctionnement de la chambre et l'on signale un certain nombre de resultats obtenus concernant, notamment, les essais de resistance a la rupture des fenetres et les mesures de dilatation thermique de compressibilite isotherme du propane utilise. (auteur)

  7. Padova e Johannesbug: farsi raccontare la zona di eccezione come pratica di cittadinanza

    Directory of Open Access Journals (Sweden)

    Elena Ostanel


    Full Text Available Via Anelli a Padova: una via che diventa un quartiere, un quartiere che diventa una città nell'immaginario collettivo. Uno spazio lasciato libero dalla distrazione del potere e delle discipline dello spazio nel quale gli abitanti "producono territorio" capace di mettere in crisi le forme consolidate di residenza e uso dello spazio pubblico. Uno spazio "difforme" che verrà chiuso da un muro, dispositivo di "controllo inverso" che esclude dalla visione e dalla comprensione di quello che accade. La "zona di eccezione" costruita dai migranti Mozambicani a Johannesburg: uno spazio distante dallo Stato dove si vive come invisibili delimitato da muri che prendono forma nei racconti dei migranti. Nella zona di eccezione vivono persone invisibili perché ai margini del sistema sociale. Ma è questa stessa marginalità che rende palese, giorno per giorno, lo scarto tra chi possiede formali requisiti di cittadinanza e chi invece "si fa cittadino" agendo sul territorio e trasformando lo spazio urbano. Se il rapporto tra popolazione e territorio è di forte interazione, allora la città diventa un luogo di mobilità, flusso e pratiche quotidiane dove le pratiche dell'abitare sono in grado di costruire esse stesse territori e popolazioni. Di fatto Via Anelli e la zona di eccezione di Johannesburg costruiscono popolazioni che ogni giorno, con il solo fatto di esistere, dimostrano la praticabilità di forme di cittadinanza ibride, multi-appartenenza e che sovrabbondano i confini dello Stato nazione.

  8. Exploration d'une expérience PV en champ électrique transverse, exploitant la détection par émission stimulée (United States)

    Jahier, E.; Guéna, J.; Lintz, M.; Jacquier, Ph.; Bouchiat, M. A.


    Nous présentons ici les premières étapes de la mise en place d'une expérience de violation de parité dans l'atome de césium, dans une nouvelle configuration expérimentale. II s'agit d'une expérience pompe-sonde, exploitant la détection par émission stimulée, où la transition d'excitation est assistée par l'application d'un champ électrique transverse. La possibilité d'appliquer un champ électrique transverse homogène dans une vapeur dense de césium vient de l'emploi de cellules en saphir, dont la conductivité électrique au contact du césium est de plusieurs ordres de grandeur inférieure à celles des cellules en verre.

  9. Die Kunst des klugen Handelns 52 Irrwege, die Sie besser anderen überlassen

    CERN Document Server

    Dobelli, Rolf


    Unzählige Leser begeistern sich für Rolf Dobellis gescheite Texte über unsere häufigsten Denkfehler. Doch wer Dobellis Ratschläge zum klaren Denken beherzigt, ist noch lange nicht aus dem Schneider, denn auf dem Weg vom Denken zum Handeln lauern weitere Fallstricke. Glücklicherweise kann man die umgehen - wenn man weiß, wie. Genau das verrät "Die Kunst des klugen Handelns": In 52 Kapiteln zeigt Dobelli, warum es sich lohnt, Türen zu schließen und auf Optionen zu verzichten, warum Informationsüberfluss zu unklugem Handeln anstiftet, warum Geld stets in emotionale Kleider gehüllt ist und wir es darum oft unbedacht ausgeben. Rolf Dobelli gibt Ihnen das nötige Rüstzeug: Schlagen Sie nicht jeden Irrweg ein, nur weil andere ihn gehen. Lernen Sie aus den Fehlern, die andere freundlicherweise für Sie machen. Denken Sie klar und handeln Sie klug!

  10. Interfon

    CERN Multimedia


    2013-01-01   Rendez-vous sur notre site pour toutes les « News » Interfon « News »   Situé au 1, rue de Lyon à Saint-Genis-Pouilly, « Optique du Lion » vous réserve un accueil chaleureux et un service personnalisé du mardi au vendredi. Tél :  04 50 28 05 33 –   Présentez votre carte de sociétaire et profitez de 14 % de remise ou d’une deuxième paire de lunettes en verres anti reflets Nous sommes indépendants et libres de pratiquer le métier que nous aimons comme nous l’aimons. Nous proposons les produits que nous avons personnellement sélectionnés. Nous prenons toujours le temps de vous écouter, pour cerner précisément vos attentes et vous recomma...

  11. La devozione alle icone medievali riscritta dal Concilio di Trento

    Directory of Open Access Journals (Sweden)

    Anita Paolicchi


    Full Text Available Il Concilio di Trento (1545-1563 determinò nuove esigenze liturgiche, che portarono a una rapida trasformazione e a un drastico rinnovamento delle chiese sia dal punto di vista strutturale che dell’arredo. Questo articolo desidera indagare i caratteri fondamentali di un fenomeno poco conosciuto e sicuramente sottovalutato della storia dell’arte moderna legata a questi cambiamenti: la ri-funzionalizzazione delle immagini medievali e bizantine, prendendo come esempio il caso toscano. In particolare verrà evidenziato come la percezione da parte dei fedeli di queste immagini si evolva nel corso dei secoli. || The Council of Trent (1545-1563 determined new liturgical requirements and specifications which brought to a rapid transformation and a radical renovation of churches from both a structural and an ornamental perspective. This article aims at investigating the fundamental features of a rarely studied and certainly underestimated artistic phenomenon of the post-Tridentine era: the changes in the function of medieval and Byzantine images, with a focus on Tuscan examples. In particular, we will examine how the worshippers’ perception of such images evolved over the centuries.

  12. A new LIFE: oltre la didattica d'aula.

    Directory of Open Access Journals (Sweden)

    Simona Scarsella


    Full Text Available A partire dal dibattito che oggi contrappone i Personal Learning Environment (PLE ai Virtual Learning Environment (VLE e le pratiche del cosidetto Learning 2.0 alle 'vecchie' pratiche educative on-line, il tutorial introdurrà€ gli uditori al Design di processi e ambienti educativi ispirati dall'idea che l'apprendimento è 'esperienza che si nutre di esperienze', nell'ambito delle quali deve essere possibile valorizzare sia le potenzialità€ della collettività€ che le caratteristiche del singolo.I partecipanti verranno altresì€ introdotti ad alcuni principi e metodiche del Design e del Co-Design che - secondo la filosofia del 'Person in Place Centered Design' - possono ispirare la trasformazione degli attuali 'learning space', spesso non-luoghi dell'apprendimento, in 'learning place', che in prospettiva potrebbero delocalizzarsi sino a diluirsi negli ambienti e nelle pratiche del vivere quotidiano assumendo caratteristiche di adattabilità€ e responsività€ tali da renderli 'place' ideali anche per trasformare e rendere più€ motivante l'attuale didattica d'aula.Il tutorial verrà€ sviluppato utilizzando LIFE (Learning in Interactive Framework to Experience, un ambiente di formazione on-line, open-source, il cui design è€ stato ispirato dai principi sopra descritti.

  13. L’esperienza della lettura in ottica cognitiva: un inquadramento teorico e un saggio di lettura di Mrs. Dalloway fra simulazione incarnata (embodied simulation e teoria della mente (theory of mind

    Directory of Open Access Journals (Sweden)

    Sara Boezio


    Full Text Available Scopo del presente lavoro è indagare il processo esperito da lettori di testi narrativi letterari in prosa. Ci si muoverà nell’ambito della narratologia cognitiva e, attingendo a recenti ricerche neuroscientifiche, ci si soffermerà in particolare su due nozioni: la nozione di ‘simulazione incarnata’, così come definita dal neurofisiologo Vittorio Gallese, membro dell’équipe che ha individuato i neuroni specchio, e la nozione di ‘teoria della mente’, elaborata in ambito filosofico e psicologico, di cui ha già cominciato a essere sondato il potenziale applicativo in campo letterario – seppur con alcuni limiti – da diversi narratologi, fra cui Lisa Zunshine e Alan Palmer. Verranno illustrati i capisaldi teorici di queste due nozioni, se ne mostreranno le divergenze e, infine, ne verrà testata l’efficacia attraverso l’analisi di alcuni brani tratti dal romanzo di Virginia Woolf Mrs. Dalloway. Emergerà come il meccanismo di simulazione incarnata alla base dell’‘embodied narratology’ si riveli uno strumento euristico fondamentale e necessario per integrare e completare la teoria della mente che, per quanto utile, non si dimostra in grado di spiegare la complessità dell’esperienza della lettura perché non rende conto del coinvolgimento corporeo che gli studi neuroscientifici hanno mostrato essere una componente di primaria importanza del nostro modo di interagire con gli altri nella realtà e, similmente, con le menti dei personaggi in un contesto finzionale.

  14. Formation des états x1 et x2 du charmonium dans l'annihilation p$\\overline{p}$ aux ISR

    CERN Document Server

    Fay, J


    Un des buts de l'expérience R704 est l'étude des états $\\chi_1$ et $\\chi_2$ du charmonium $(c\\bar{c)}$ dans leur annihilation J/$\\psi$ + photon. Ces états sont formés par interaction d'un jet moléculaire d'hydrogène sur un faisceau refroidi d'antiprotons. L'importance du bruit de fond hadronique conduit à ne s'intéresser qu'aux états finaux électromagnétiques. L'appareillage de détection est essentiellement constitué de deux bras symétriques non magnétiques en deux parties. La première s'intéresse seulement aux particules chargées : mesure de leur direction (chambres à fils scintillateurs) et identification des électrons (Cerenkov). La deuxième forme un calorimètre mesurant la position et l'énergie des photons et électrons (sandwiches plomb-scintillateur chambres proportionnelles à lecture cathodique et mur de verre au plomb). L'analyse des données est fondée sur la reconnaissance d'une paire d'électrons provenant d'un $\\Psi$, puis la recherche du photon associé, déduit de la re...

  15. O “espaço de morar” na arquitetura moderna: reflexões a partir de quatro residências de Irati – PR / The “dwelling space” in modern architecture: reflections on four residential buildings in Irati – Paraná (Brazil

    Directory of Open Access Journals (Sweden)

    Gigliese Aparecida Mendes


    Full Text Available Este artigo analisa o 'espaço de morar' influenciado pelo movimento modernista na cidade de Irati – PR, enfatizando seu aspecto espacial. A análise ocorre a partir de quatro residências unifamiliares construídas durante a década de 1950, projetadas por Eduardo Posfaldo, profissional local. Nestas são observados elementos arquitetônicos característicos do modernismo, como os pans de verr e pilotis. Valorizando-se as linhas retas, o 'espaço de morar' é concebido de forma racionalista. A partir da análise destas habitações, foi constatado que estas ocupam um percentual relativamente pequeno (31% de seus lotes, o que permite inferir a importância das áreas verdes e jardins nesta modalidade de 'espaço de morar'. No interior das habitações, a ênfase em termos de área está nos espaços íntimos (28,5%, seguidos dos espaços sociais (26%. Um aspecto singular encontrado em Irati é o compartilhamento do 'espaço de morar' com o 'espaço profissional'.

  16. Interfon

    CERN Document Server



      Assemblée générale de la Mutuelle Vendredi 25 novembre à 18h30 Cafétéria Jean Monnet – St-Genis Au cours de cette soirée vous seront présentés : le compte-rendu des activités de l’année 2011, le bilan de la gestion financière pour l’année 2010, les nouvelles cotisations pour l’année 2012. Enfin le traditionnel verre de l’amitié sera offert à l'issue de cette soirée. * * * * * * * Idées de cadeaux de Noël !!!   Découvrez le site internet : * * * * * * * Z.A. de la Maladière 01210 Ornex Votre spécialiste de l’image & du son dans le Pays de Gex Plus de 300 m² d’exposition dédiés &...

  17. Interfon

    CERN Document Server



    Les membres du Conseil d’Administration ainsi que le personnel de la Coopérative et de la Mutuelle vous souhaitent un Joyeux Noël et une Bonne Année 2012 ! Nos bureaux seront fermés : Au CERN du 22 décembre au 4 janvier inclus Au Technoparc du 23 décembre au 1er janvier inclus Quelques idées de cadeaux à offrir ou à s’offrir ! Des billets d’entrée ou des abonnements, à tarifs réduits (15 % de réduction), pour le Vitam’Parc. A la Vinothèque du Leman (zone de l’Allondon à St-Genis) vous trouverez : verres à dégustation, carafes, paniers à bouteilles, écrins cadeaux … tout pour le parfait œnologue. Remise de 5 à 10 %. Mais également,  coffrets bois, panie...

  18. Die verenigde state van Amerika en Suid-Afrika

    Directory of Open Access Journals (Sweden)

    C. F. Muller


    Full Text Available Die bedrywighede van die mens in Suid-Afrika is oor die eeue deur die burgers van baie lande beïnvloed en gevorm. Ontdekkingsreise, handel en kolonisasie het byvoorbeeld Portugese, Nederlanders, Engelse en Franse na die onherbergsam e kuste van ons Suidland gebring. Net nadat Diaz die Storm kaap omseil het, het Columbus die eilandegordel voor die Amerikaanse kuste en ’n groot kontinent aan Europa bekend gestel. Hierdie nuwe land na die verre noordweste van Suid-Afrika, wat in sekere opvallende opsigte parallel met Suid-Afrikaanse hoofstrominge ontwikkel het, en wie se lotgevalle terselfdertyd so verskillend uitgeval het, sou bestem wees om in latere eeue algaande ’n steeds belangriker invloed op Suid- Afrika uit te oefen. Vandag as leier van die W esterse moondhede (waaraan Suid-Afrika ook behoort is die Verenigde State van Amerika ’n transkontinentale reus van sowat 180 miljoen inwoners en is sy invloed op Suid- Afrika in resente jare so opvallend dat ons bykans elke week daarom trent in nuusblaaie en tydskrifte lees, of op die radio daarvan hoor.

  19. Editorial

    Directory of Open Access Journals (Sweden)

    Editorial Office


    Full Text Available Ons is weereens bevoorreg om nog ’n uitgawe van In die Skriflig aan ons lesers aan te bied. In hierdie uitgawe gee die bekende Potchefstroomse filosoof, B.J. van der Walt perspektiewe oor ’n Christelike samelewingsbeskouing. Hierdie tema is vir die gere- formeerde teologie van die uiterste belang, veral in die huidige tydsgewrig in Suid-Afrika waarin die godsdiens enersyds so maklik vergeestelik en andersyds so maklik veramptelik word. Dit is nodig dat ons weer wetenskaplik besin oor die aard en roeping van verskillende samelewingsverbande binne die koninkryk van God. Veral is die sosiale roeping van die geïnstitueerde kerk weer van belang soos blyk uit die teoenemende politieke rol wat kerke begin inneem as deel van die burgerlike samelewing se konfrontasie met die sterk sentrale regering. Is dit byvoorbeeld die taak van kerke om as moniteerders op te tree by verkiesings in buurlande en in hoe- verre moet die kerke hulle besig hou met voorgestelde wetgewing? Gaan dit nog om kerklike sake op ’n kerklike wyse soos art. 30 van die Dortse kerkorde bepleit? Hopelik stimuleer die besinning van Van der Walt diepsinnige nadenke oor die saak in gereformeerde kringe.

  20. Produktiwiteit en verantwoordelikheid, enkele sielkundige aspekte

    Directory of Open Access Journals (Sweden)

    A. P. Venter


    Full Text Available Some psychological aspects of Maslow's motivation theory are discussed with a view to pointing out the usefulness of this theory in the industrial situation. It is suspected that industrial psychologists do not always interpret Maslow's theory correctly. The aspect of responsibility in the need for selfactualization seems to be undervalued, in some instances completely unrecognized. A logical conclusion drawn is that self-actualization, in accordance with Maslow's own description, is related to productivity.OpsommingMaslow se motiveringsteorie wat uit die kliniese sielkunde ontspruit het, is ook deur bedryfsielkundiges van nader beskou, veral in hoe verre dit met produktiwiteit verband het. Enkele sielkundige aspekte word bespreek ten einde op die nut van hierdie teorie in die bedryfsituasie te wys. Die vermoede bestaan dat die teorie deur bedryfsielkundiges nie altyd korrek vertolk word soos Maslow dit self uiteensit nie; veral word die verantwoordelikheidsaspek in die selfuitlewingsbehoeftes misken en nie verreken nie; 'n Logiese konklusie is dat selfuitlewing, soos deur Maslow beskryf, wel verband met produktiwiteit het.

  1. Radial Fingering in a Porous Medium Digitation radiale dans un milieu poreux

    Directory of Open Access Journals (Sweden)

    Ni W.


    Full Text Available The theory of immiscible radial displacement in a Hele-Shaw cell is extended to the case of a porous medium contained between two closely-spaced parallel plates, and experiments are described for the displacement of glycerine by paraffin oil in such a system. Data are presented for the number of fingers, the breakthrough time, and the glycerine recovery, for a range of flowrates varying through three orders of magnitude. Good agreement between theory and experiment is observed. La théorie s'appliquant aux déplacements radiaux dans les cellules Hele-Shaw a été étendue à un système qui consiste en une couche mince de milieux poreux encapsulée entre deux plaques en verre. Dans cet article, on examine les déplacements de la glycérine par de l'huile de paraffine. En faisant varier le débit de l'huile de paraffine dans un intervalle de trois ordres de grandeur, on a étudié les variables telles que le nombre de digitations, le temps de percée et le taux de récupération de la glycérine. On a observé un bon accord entre la théorie et les résultats expérimentaux.

  2. Korte signaleringen

    Directory of Open Access Journals (Sweden)

    Harry A. Poeze


    Full Text Available J. Thomas Lindblad en Alicia Schrikker (red., Het verre gezicht: Politieke en culturele relaties tussen Nederland en Azië, Afrika en Amerika: Opstellen aangeboden aan prof.dr. Leonard BlusséBen Koolen, VOC & onderwijs: Een inventarisatieMyriam Everard en Ulla Jansz (red., De minotaurus onzer zeden: Multatuli als heraut van het feminismeMarita Mathijsen (red., Boeken onder druk: Censuur en personvrijheid in Nederland sinds de boekdrukkunstMargaret Leidelmeijer (red., Het verhaal van IndiëEsther Zwinkels, Het Overakker-complot: Indisch verzet tegen de Japanse bezetter op Sumatra 1942-1945Peter Schumacher, Ogenblikken van genezing: De gewelddadige dekolonisatie van IndonesiëEsther Captain en Guno Jones, Oorlogserfgoed overzee: De erfenis van de Tweede Wereldoorlog in Aruba, Curaçao, Indonesië en SurinameCasper van Bruggen, ‘Verget ons niet’: Het Papoea Vrijwilligers Korps (1961-1963Victor Kaisiëpo Msn, Een perspectief voor Papoea’s: Het verhaal van mijn leven en mijn strijd

  3. Ricerca empirico-sperimentale in pedagogia… Alcuni appunti su riflessione teorica e sistematicità metodologica.

    Directory of Open Access Journals (Sweden)

    Ira Vannini


    Full Text Available In questo breve saggio, si vogliono ripercorrere le fasi principali attraverso le quali si sviluppa un percorso di ricerca empirica e sperimentale in educazione, allo scopo di riflettere su alcune questioni importanti che si propongono al ricercatore durante il suo lavoro di indagine. Negli ultimi decenni, il dibattito nazionale e internazionale a questo proposito è stato molto vivace e complesso; la presente trattazione non pretende dunque di essere in alcun modo esaustiva, bensì mira a delineare i momenti più significativi che caratterizzano un itinerario di indagine e a sottolineare il valore del fare ricerca in educazione quale prassi – di pensiero e di azione – che esige di essere, da un lato, teoricamente fondata e, dall’altro lato, metodologicamente rigorosa. Nel saggio verrà prediletto l’approccio più propriamente sperimentale e quantitativo, al fine di evidenziarne le peculiarità e le valenze nell’ambito della ricerca empirica in pedagogia; tale approccio sarà tuttavia analizzato e discusso criticamente alla luce delle più recenti riflessioni sui paradigmi teorici della ricerca nelle scienze sociali e sulle possibilità e i limiti dell’integrazione, teorica e metodologica, tra approcci quantitativo e qualitativo.

  4. Pétrographie du kérogène dans le Paléozoïque inférieur : méthode de préparation et exemple d'application Petrography of Lower-Paleozoic Kerogen: Preparation Method and Applied Example

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    Bertrand R.


    Full Text Available Une nouvelle méthode de préparation des matières organiques dispersées, destinées à être étudiées au microscope, est décrite et proposée. Le montage de la matière organique est fait par des lames de verre. Il permet de faire tous les types d'observations microscopiques (lumière transmise, réfléchie ou fluorescente sur une même préparation. Ses avantages sur la méthode classique d'imprégnation sur des briquettes sont illustrés par un exemple dans la séquence ordovicienne et siluro-dévonienne de l'île d'Anticosti et de l'est des Appalaches québécoises au Canada. This paper presents a new method to be used in the preparation of dispersed organic matter for microscopic studies. The organic matter is spread on a glass slide in order to permit all types of microscopic observation (transmitted, reflected or fluorescent light on a single mount. An example of its application, taken from the Ordovician and Siluro-Devonian sequence of Anticosti Island and Eastern Appalachians of Quebec, shows the advantages of this new method over the traditional plugmethod.


    CERN Multimedia



    Assemblée Générale de la Mutuelle Mardi 16 novembre à 18h30 Salle du Business Center Technoparc de St-Genis (entrée nord)   Au cours de cette soirée vous seront présentés : Le compte-rendu des activités de l’année 2010 Le bilan de la gestion financière pour l’année 2009 Les nouvelles cotisations pour l’année 2011 Enfin le traditionnel verre de l’amitié Clôturera cette soirée.   ******   Nouveau … Nous venons de passer un accord de partenariat avec le Cellier Mövenpick (Ch. du Grand Pré à Meyrin) où vous pourrez prochainement bénéficier de tarifs avantageux sur tous les vins en provenance du monde entier. Cet avantage sera consenti, dès le dé...

  6. Geochemistry of olivine-hosted melt inclusions in the Baekdusan (Changbaishan) basalts: Implications for recycling of oceanic crustal materials into the mantle source (United States)

    Choi, Hyun-Ok; Choi, Sung Hi; Schiano, Pierre; Cho, Moonsup; Cluzel, Nicolas; Devidal, Jean-Luc; Ha, Kyoochul


    We determined the major and trace element concentrations of olivine-hosted melt inclusions in basalts from the active Baekdusan volcano situated on the border between China and North Korea in order to understand better the nature of the mantle source and the geodynamic processes that gave rise to volcanism at this site. Rehomogenized melt inclusions (after 'Fe-loss' correction) can be divided into three groups: a low-Si alkaline group, a high-Si alkaline group, and a high-Si sub-alkaline group. The low-Si group is composed of picrobasalt to basanite, and the high-Si group consists of (trachy)basalt to basaltic (trachy)andesite. The low-Si group has generally higher TiO2, CaO, and P2O5, but lower Al2O3, Na2O, and K2O contents at a given MgO concentration compared with those in the high-Si group. The CaO and P2O5 contents are positively correlated, indicating the presence of a calcium phosphate, probably tuite [γ-Ca3(PO4)2], in the source. The melt inclusions are enriched in light rare earth elements [(La/Yb)N = 7.8-30.4]. On a primitive-mantle-normalized incompatible element plot, the low-Si group has positive anomalies in Ba and P compared with typical oceanic island basalt (OIB). On the other hand, the high-Si group exhibits remarkable positive anomalies in Eu, Ba, Rb, K, Pb, P, and Ti, implying that K-hollandite and tuite are essential phases in the source. The high-Si subalkaline group has lower abundances of incompatible elements than the high-Si alkaline group, reflecting different degrees of partial melting from the same source. In contrast to OIB, Baekdusan magmatism is characterized by positively fractionated (Zr/Hf)N ratios, and is best approximated by admixture of partial melts derived from both clinopyroxene-rich eclogite and garnet peridotite. Intraplate volcanism in northeastern Asia is closely associated with deep subduction of the Pacific plate. The subducting Pacific slab flattens and stagnates in the mantle transition zone under northeastern Asia

  7. Identifying Key Structural Features of IrOx Water Splitting Catalysts. (United States)

    Willinger, Elena; Massué, Cyriac; Schlögl, Robert; Willinger, Marc Georg


    Hydrogen production by electrocatalytic water splitting will play a key role in the realization of a sustainable energy supply. Owing to their relatively high stability and activity, iridium (hydr)oxides have been identified as the most promising catalysts for the oxidation of water. Comprehensive spectroscopic and theoretical studies on the basis of rutile IrO2 have provided insight about the electronic structure of the active X-ray amorphous phase. However, due to the absence of long-range order and missing information about the local arrangement of structural units, our present understanding of the active phase is very unsatisfying. In this work, using a combination of real-space atomic scale imaging with atomic pair distribution function analysis and local measurements of the electronic structure, we identify key structural motifs that are associated with high water splitting activity. Comparison of two X-ray amorphous phases with distinctively different electrocatalytic performance reveals that high activity is linked to the ratio between corner- and edge-sharing IrO6 octahedra. We show that the active and stable phase consists of single unit cell sized hollandite-like structural domains that are cross-linked through undercoordinated oxygen/iridium atoms. In the less active phase, the presence of the rutile phase structural motif results in a faster structural collapse and deactivation. The presented results provide insight into the structure-activity relationship and promote a rational synthesis of X-ray amorphous IrOx hydroxides that contain a favorable arrangement of structural units for improved performance in catalytic water splitting.

  8. New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA (United States)

    Carmichael, Sarah K.; Doctor, Daniel H.; Wilson, Crystal G.; Feierstein, Joshua; McAleer, Ryan J.


    Manganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace and rare earth element (REE) geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered alluvial deposits that occur close to breccia-hosted Mn deposits in Virginia show geochemical signatures that are distinct from the breccia matrices and appear to reflect remobilization of earlier-emplaced Mn and concentration within supergene traps. Based on the proximity of all of the productive ore deposits to mapped faults or other zones of deformation, we suggest that the primary source of all of the Mn may have been deep seated, and that Mn oxides with supergene and/or biological characteristics resulted from the local remobilization and concentration of this primary Mn.

  9. Shock Metamorphism of L6 Chondrites Sahara 98222 and Yamato 74445: the P-T Conditions and the Shock age (United States)

    Ozawa, S.; Ohtani, E.; Suzuki, A.; Miyahara, M.; Terada, K.; Kimura, M.


    Impact phenomena are the fundamental processes of accretion of the terrestrial planets. Therefore, investigations of meteorites that experienced shock events are useful for understanding mechanisms of planetary impact events and formation of terrestrial planets. Heavily shocked meteorites contain abundant shock melt veins, where some high-pressure minerals have been discovered. In this study, we investigated mineralogy of shock melt veins of two L6 chondrites (Sahara 98222 and Yamato 74445) and estimated the P-T conditions during their impact events.We found that the shock melt veins of these meteorites contain several high-pressure minerals such as wadsleyite, jadeite and tuite for Sahara 98222 and ringwoodite (+ wadsleyite), akimotoite and lingunite for Yamato 74445. Tuite is a high-pressure polymorph of whitlockite and lingunite is a high-pressure polymorph of albite with hollandite structure. Based on mineralogy in the shock veins; we estimated the pressure and temperature conditions during their impact events: 13-15 GPa, > 2000°C for Sahara 98222 and 15- 24 GPa, > 2200°C for Yamato 74445, respectively.We also conducted a U-Pb dating of phosphates in and around the shock melt veins of Sahara 98222 using a Sensitive High Resolution Ion Micro Probe (SHRIMP-II) at Hiroshima University to reveal when this shock event occurred. We obtained following radioactive ages: Pb-Pb isochron age: 4466 ± 31 Ma; U-Pb isochron age: 4498 ± 150 Ma; Total U-Pb isochron age: 4467 ± 22 Ma. These ages seem to be slightly younger than the previously reported ages of chondrites, which are usually older than 4500 Ma. This could suggest that Sahara 98222 have recorded a shock event in the very early stage of the solar system where the planetary formation was going on.

  10. High-pressure minerals in shocked L6-chondrites: constraints on impact conditions (United States)

    Ohtani, E.; Kimura, Y.; Kimura, M.; Kubo, T.; Takata, T.


    We have studied the high-pressure phases observed in Yamato 791384 and ALH78003 L6-chondrites. Host meteorite consists mainly of olivine, pyroxenes, and plagioclase glass. Mineral fragments observed in the veins and the vein margin region of these meteorites were partially or totally transformed into high-pressure phases wadsleyite, ringwoodite, majorite, akimotoite, NaAlSi3O8 hollandite and jadeite. Whereas matrix of the shock vein contains majorite-pyrope solid solution in both meteorites. The spatial distribution indicates that high-pressure phases are present in the shock veins and host rocks adjacent to the shock veins. Investigation of the high-pressure phases revealed that, in Y791384, fragments and adjacent matrix were subjected to pressures around 18 23 GPa and the vein experienced temperatures around 2,000 2,300°C during the shock event. ALH78003 experienced the shock pressure of about 15 18 GPa at 2,000°C. Ringwoodite lamellae were observed in the host olivine adjacent to the vein in Y791384. Kinetic investigation for ringwoodite lamellar growth in olivine indicates that the meteorite experienced an impact with a pressure around 20 GPa for more than 4 s of the pressure pulse indicating a large impactor with the size greater than 10 km. ALH78003 contains wadsleyite ringwoodite aggregates in the shock veins. The ringwoodite grains have wadsleyite rim enriched in Mg2SiO4 component. The compositional profiles of wadsleyite rim and ringwoodite core of the fragments in the shock veins in ALH78003 cannot be explained by a simple Mg Fe inter-diffusion process.

  11. High-pressure phases in shock-induced melt veins of the Umbarger l6 chondrite: Constraints of shock pressure (United States)

    Xie, Zhidong; Sharp, Thomas G.


    We report a previously undocumented set of high-pressure minerals in shock-induced melt veins of the Umbarger L6 chondrite. High-pressure minerals were identified with TEM using selected-area electron diffraction, and energy-dispersive X-ray spectroscopy. Ringwoodite (Fa30), akimotoite (En11Fs89), and augite (En42Wo33Fs25) were found in the silicate matrix of the melt vein, representing the crystallization from a silicate melt during the shock pulse. Ringwoodite (Fa27) and hollandite-structured plagioclase were also found as polycrystalline aggregates in the melt vein, representing solid-state transformation or melting with subsequent crystallization of entrained host-rock fragments in the vein. In addition, Fe2SiO4-spinel (Fa66-Fa99) and stishovite crystallized from a FeO-SiO2-rich zone in the melt vein, which formed by shock melting of FeO-SiO2-rich material that had been altered and metasomatized prior to shock. Based on the pressure stabilities of the high-pressure minerals, ringwoodite, akimotoite, and Ca-clinopyroxene, the melt vein crystallized at approximately 18 GPa. The Fe2SiO4-spinel + stishovite assemblage in the FeO-SiO2-rich melts is consistent with crystallization of the melt-vein matrix at the pressure up to 18 GPa. The crystallization pressure of ?18 GPa is much lower than the 45-90 GPa pressure one would conclude from the S6 shock effects in melt veins (St?ffler et al. 1991) and somewhat less than the 25-30 GPa inferred from S5 shock effects (Schmitt 2000) found in the bulk rock.

  12. Host rock solid-state transformation in a shock-induced melt vein of Tenham L6 chondrite (United States)

    Xie, Zhidong; Sharp, Thomas G.


    The host-rock fragments entrained in a 580-μm-wide melt vein of the Tenham L6 chondrite were investigated using field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) to better understand the solid-state transformation mechanisms and the shock conditions. The melt vein consists of a matrix of silicate plus metal-sulfide that crystallized from immiscible melts, and sub-rounded host-rock fragments that have been entrained in the melt and transformed to polycrystalline high-pressure silicates by solid-state transformation mechanisms. These high-pressure phases include ringwoodite, low-Ca majorite, clinoenstatite, hollandite-structured plagioclase and Ca-rich majorite. The Ca-rich majorite occurs as a symplectitic intergrowth with a Ca-poor amorphous silicate phase in a 200 μm-diameter chondrule in the vein. This intergrowth seems to be the result of a disproportionate breakdown of a Ca-rich clinopyroxene precursor into Ca-rich majorite and (FeMg)SiO 3 perovskite, which subsequently vitrified upon pressure release. The TEM observations suggest that most solid-state transformations in the Tenham are reconstructive. The transformation of olivine to polycrystalline ringwoodite appears to involve incoherent intracrystalline nucleation and interface-controlled growth. Lamellae in partially transformed olivine are not continuous coherent lamellae, but rather lamellae of polycrystalline ringwoodite, which is inconsistent with a coherent lamellar transformation mechanism. Growth rate calculations based on published kinetic data suggest that the time required to grow 1 μm ringwoodite crystal is ˜ 100 ms at 1600 K, suggesting that the minimum shock pulse of approximately 100 ms.

  13. Effects of Optical Dopants and Laser Wavelength on Atom Probe Tomography Analyses of Borosilicate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaonan; Schreiber, Daniel K.; Neeway, James J.; Ryan, Joseph V.; Du, Jincheng


    Atom probe tomography (APT) is a novel analytical microscopy method that provides three dimensional elemental mapping with sub-nanometer spatial resolution and has only recently been applied to insulating glass and ceramic samples. In this paper, we have studied the influence of the optical absorption in glass samples on APT characterization by introducing different transition metal optical dopants to a model borosilicate nuclear waste glass (international simple glass). A systematic comparison is presented of the glass optical properties and the resulting APT data quality in terms of compositional accuracy and the mass spectra quality for two APT systems: one with a green laser (532 nm, LEAP 3000X HR) and one with a UV laser (355 nm, LEAP 4000X HR). These data were also compared to the study of a more complex borosilicate glass (SON68). The results show that the analysis data quality such as compositional accuracy and total ions collected, was clearly linked to optical absorption when using a green laser, while for the UV laser optical doping aided in improving data yield but did not have a significant effect on compositional accuracy. Comparisons of data between the LEAP systems suggest that the smaller laser spot size of the LEAP 4000X HR played a more critical role for optimum performance than the optical dopants themselves. The smaller spot size resulted in more accurate composition measurements due to a reduced background level independent of the material’s optical properties.

  14. On the Coordination of Actinides and Fission Products in Silicate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Haddi, Anne; /Marne la Vallee U.; Farges, Francois; /Marne la Vallee U. /Museum Nat. Hist., Paris /Stanford U., Geo. Environ. Sci.; Trocellier, Patrick; /Saclay; Curti,; /Paul Scherrer Inst.; Harfouche, Messaoud; /Marne la Vallee U.; Brown, Gordon E.; /Stanford U., Geo. Environ. Sci. /SLAC, SSRL


    The local structure around Th, U, Ce and Nd in leached silicate glasses was examined using XAFS spectroscopy at their L3 edges and also at the K edge of Fe, Co, Ni, Zr and Mo. Pellets of inactive borosilicate glasses with a simplified or a complex composition were leached statically at 90 C, at pH buffered to 0 or 6 for 28 days (surface/volume, S/V, ratios of 0.1 cm{sup -1}). These glasses are compared to another SON68 sample (denoted ''SP1'' in this paper) that was statically leached for 12 years under similar conditions, except for a higher S/V of 12 cm{sup -1} and a higher unconstrained pH of 9.6. The speciation of Fe, Co, Ni, Zr and Mo in the simple and the complex unleached are similar. In the statically leached glasses, the speciation of these transition metals is mostly identical to in the unleached glasses, except in the gels formed at the surface of the glasses leached at low pH, where large speciation differences are observed. Surface precipitates, especially for Fe (as ferrihydrite), Mo (possibly sidwillite) and Th (as ThO{sub 2}) were detected. Finally, the drying of the gels considerably affects the metal speciation by enhancing metal polymerization.

  15. Ion-Exchange Interdiffusion Model with Potential Application to Long-Term Nuclear Waste Glass Performance

    Energy Technology Data Exchange (ETDEWEB)

    Neeway, James J.; Kerisit, Sebastien N.; Liu, Jia; Zhang, Jiandong; Zhu, Zihua; Riley, Brian J.; Ryan, Joseph V.


    Abstract: Ion exchange is an integral mechanism influencing the corrosion of glasses. Due to the formation of alteration layers in aqueous conditions, it is difficult to conclusively deconvolute the process of ion exchange from other processes, principally dissolution of the glass matrix. Therefore, we have developed a method to isolate alkali diffusion that involves contacting glass coupons with a solution of 6LiCl dissolved in functionally inert dimethyl sulfoxide. We employ the method at temperatures ranging from 25 to 150 °C with various glass formulations. Glass compositions include simulant nuclear waste glasses, such as SON68 and the international simple glass (ISG), glasses in which the nature of the alkali element was varied, and glasses that contained more than one alkali element. An interdiffusion model based on Fick’s second law was developed and applied to all experiments to extract diffusion coefficients. The model expands established models of interdiffusion to the case where multiple types of alkali sites are present in the glass. Activation energies for alkali ion exchange were calculated and the results are in agreement with those obtained in glass strengthening experiments but are nearly five times higher than values reported for diffusion-controlled processes in nuclear waste glass corrosion experiments. A discussion of the root causes for this apparent discrepancy is provided. The interdiffusion model derived from laboratory experiments is expected to be useful for modeling glass corrosion in a geological repository when the silicon concentration is high.

  16. Improvement of Heavy Oil Recovery in the VAPEX Process using Montmorillonite Nanoclays Amélioration de la récupération d’huile lourde par utilisation de nanoargiles de Montmorillonite dans le procédé VAPEX

    Directory of Open Access Journals (Sweden)

    Pourabdollah K.


    hydrocarbures dans les chambres balayees au cours des procedes VAPEX nano-assiste et conventionnel. Les experiences ont ete realisees en utilisant une huile lourde iranienne et du propane : le dispositif experimental consistait en deux cellules garnies de sable, l’une garnie uniquement avec des billes de verre en tant que milieu poreux et l’autre avec des billes de verre et de la montmorillonite modifiee en tant que nanoargile; les deux avaient la meme porosite et la meme permeabilite. La teneur en asphaltene depose dans les zones balayees, le profil de propagation des chambres de vapeur ainsi que les taux de consommation de solvant et de production d’huile ont ete determines. Les resultats ont mis en evidence que la montmorillonite a modifie l’heterogeneite du milieu poreux et a conduit a former des percees accrues, a augmenter la surface interfaciale solvant/bitume et a accelerer la production d’huile. Il s’est avere que non seulement le debit d’injection de solvant a ete diminue, mais que la recuperation d’huile lourde a egalement ete sensiblement accrue de 30 (±4 %.

  17. Pseudoscorpionida (Arachnida em galerias de colônias de Passalidae (Coleoptera, Insecta em troncos caídos em floresta de terra firme da Amazônia, Brasil Pseudoscorpionida (Arachnida found in the galleries made by Passalidae (Coleoptera, Insecta colonies inside fallen wood of the Amazonian terra firme forest, Brazil

    Directory of Open Access Journals (Sweden)

    Nair Otaviano Aguiar


    Full Text Available Em sete municípios do Amazonas, um de Rondônia e um de Roraima, foram examinadas 71 colônias de 24 espécies de Passalidae (Coleoptera, pertencentes aos gêneros: Passalus Fabricius, 1792 (14 espécies; Paxillus Mac Leay, 1819 (três; Popilius Kaup, 1871 (três; Spasalus Kaup, 1869 (uma; Verres Kaup, 1871 (uma; Veturius Kaup, 1871 (duas. Foram registradas doze espécies de pseudoscorpiões, incluindo nove gêneros e cinco famílias, listadas a seguir: Chernetidae - Americhernes aff. incertus Mahnert, 1979, Cordylochernes scorpioides (Linnaeus 1758, Lustrochenes similis (Balzan 1892, L. aff. reimoseri Beier, 1932, L. intermedius (Balzan 1892, Phymatochernes crassimanus Mahnert 1979; Chthoniidae - Pseudochthonius homodentatus Chamberlin, 1929; Lechytiidae - Lechytia chthoniiformis (Balzan 1887; Tridenchthoniidae - Tridenchthonius mexicanus Chamberlin & Chamberlin 1945; Withiidae - Cacodemonius sp., Dolichowithius (D. emigrans (Tullgren 1907, D. (D. mediofasciatus Mahnert, 1979. Dentre as espécies mais freqüentes (T. mexicanus, L. intermedius e L. aff. reimoseri, ocorreram todos os estágios de desenvolvimento. Foram coletadas de uma a três espécies de pseudoscorpiões em cada colônia individual de besouros passalídeos. T. mexicanus foi a única espécie encontrada em todos os municípios, ocorrendo em 45 colônias de dezenove espécies de passalídeos, sendo a maioria dos exemplares encontrado no subcórtex. L. intermedius foi a segunda espécie mais abundante, ocorrendo em colônias de 11 espécies de Passalidae, a maioria também no subcórtex. L. aff reimoseri ocorreu em 13 colônias de Passalidae, sob a casca, alburno e cerne. L. aff. reimoseri foi a única espécie coletada somente no cerne.Seventy-one colonies from 24 species of Coleoptera, Passalidae, belonging respectively to the genera Passalus Fabricius, 1792 (14 species, Paxillus Mac Leay, 1819 (three species, Popilius Kaup, 1871 (three species, Spasalus Kaup, 1869 (one species

  18. Tests on dynamic corrosion by water. Influence of the passage of a heat flux on the corrosion kinetics. pH measurement in water at high temperature; Essais de corrosion dynamique par l'eau. Influence du passage d'un flux thermique sur la cinetique de corrosion. Mesure du pH dans l'eau a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Coriou, H.; Grall, L.; Hure, J.; Saint-James, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Berthod [Societe Grenobloise d' Etudes et d' Applications Hydrauliques, 38 (France); Le peintre [Centre National de la Recherche Scientifique (CNRS), 38 - Grenoble (France)


    'eau sous pression a une temperature voisine de 280 deg. C, la vitesse de circulation atteint 6 m/s. On etudie, du point de vue de la corrosion, les resultats obtenus, sur des gaines en aluminium, en attachant beaucoup d'attention aux phenomenes de cavitation susceptibles de causer de graves degats dans certaines circonstances particulieres. Apres avoir mis au point un dispositif d'electrode en verre pouvant supporter des pressions elevees les auteurs ont fait des recherches concernant les materiaux susceptibles de fonctionner comme electrode d'hydrogene et capables de resister convenablement a la corrosion par l'eau a 200 deg. C. Diverses possibilites ont ete examinees: electrodes de verres speciaux, de quartz, metallique, a membrane etc. On donne les resultats des differents essais et les limites pratiques d'utilisation. (auteur)

  19. Systèmes multimatériaux – Assemblage par collage Multimaterial systems – Adhesive bonding

    Directory of Open Access Journals (Sweden)

    Zuanna C. Dalla


    Full Text Available L'assemblage par collage multimatériaux (métal/composite, métal/verre, métal/plastiques, verre/plastiques… offre de nombreux avantages par rapport aux techniques d'assemblages traditionnelles (pas d'affaiblissement des matériaux par la température, tenues en fatigue et à la corrosion améliorées, esthétisme, étanchéité…. Cependant la qualité et la durabilité à long terme des assemblages collés dépendent d'une bonne conception de ces assemblages : Le choix de préparations de surfaces efficaces, robustes, facilement industrialisables et respectueuses de l'environnement, Le choix d'adhésifs aptes à répondre au cahier des charges fonctionnel de l'assemblage (performances mécaniques, thermiques, chimiques… dont la mise en œuvre est compatible avec les contraintes d'industrialisation (cadences, temps de manipulation des pièces, environnement du poste collage…, Le dessin et le dimensionnement de la liaison de façon à transmettre les efforts mécaniques spécifiés dans la plage de températures de fonctionnement des pièces collées (en tenant compte des dilatations différentielles des matériaux assemblés. Cette démarche sera développée en donnant l'état de l'art actuel et les avancées les plus récentes sur les trois thèmes cités ci-dessus. Adhesive-bonding offers many advantages over traditional joining techniques (no weakening of materials by temperature, required fatigue and improved corrosion resistance, aesthetics, sealing… for multimaterial assembly (metal/composite, metal/glass, metal/plastic, glass/plastic…. However the quality and long term durability of bonded assemblies depend on a correct design of the joint: Choice of eco-efficient surfaces preparations, robust, and easily processed, Choice of adhesive in good adequation with the functional specifications of the assembly (mechanical performance, thermal, chemical… whose implementation is compatible with industrialization constraints

  20. Ripensare l’integrazione attraverso lo sport: la partecipazione sportiva a livello comunitario dei migranti turchi in Francia

    Directory of Open Access Journals (Sweden)

    William Gasparini


    Full Text Available Storicamente, la Francia è una terra d’immigrazione già a partire dal XIX secolo, periodo in cui lo sport moderno si è sviluppato. Progressivamente, i migranti e i loro discendenti si sono mescolati nello “creuset français” anche attraverso il contributo che lo sport ha dato all’integrazione sociale di numerosi sportivi migranti. Lo sport (e più particolarmente il calcio si presenta dunque come un terreno di studio particolarmente interessante sia sull’ambito delle espressioni di identità che sulle nuove forme del “vivere insieme”. L’articolo propone di mettere questi aspetti alla prova dei fatti analizzando la pratica sportiva dei migranti turchi, l’ultima grande onda di migranti in Francia e prima comunità di migranti in Europa. I dati empirici raccolti nell’ambito dei club turchi nella regione d’Alsazia (nord-est della Francia mostrano la presenza, chiara, di un raggruppamento comunitario che pone una serie di domande: tali raggruppamenti esistono poiché costretti o derivano da una scelta fatta in senso militante ? Da questo punto di vista, in che modo lo sport permette la loro coesione e la loro integrazione sociale ? Al di là della sola “identità turca” verrà dimostrato che l’esistenza di un club “turco” nell’ambito della società di accoglienza e la partecipazione sportiva a livello comunitario sono legati a dei fattori sociali e politici. Nel mettere in luce le cause sociali dei raggruppamenti sportivi, l’articolo intende inoltre superare l’opposizione classica tra la socializzazione comunitaria e la socializzazione societaria.

  1. Effets de l'exposition à un insecticide carbamate, le carbofuran, sur les performances de jeunes stades de brochet (Esox lucius L., 1758 : résultats préliminaires

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    Full Text Available Des lots de jeunes brochets au stade embryon libre, stabulés dans des béchers en verre, ont été exposés en conditions statiques à des solutions (0-250 µg.L-1 de carbofuran, un insecticide carbamate inhibiteur de l'activité de l'acétylcholinestérase (AchE. A partir de 10 µg.L-1, une inhibition significative de l'activité globale de l'AchE des embryons libres a été constatée. A partir de 50 µg.L-1, une diminution significative de la hauteur moyenne de fixation des embryons libres sur les parois des béchers a été observée. L'exposition au carbofuran n'a pas eu d'effet significatif sur le nombre de proies zooplanctoniques ingérées par les jeunes brochets parvenus au début de la phase larvaire ; une diminution de ce paramètre en fonction de concentrations croissantes de carbofuran a cependant été enregistrée. A 250 µg.L-1 , la résorption de la vésicule vitelline ne s'effectuant plus que très partiellement, les embryons libres exposés ne se sont pas transformés en larves. Cette étude montre que l'exposition à des concentrations sublétales de carbofuran est susceptible d'affecter le développement ontogénétique et les performances de jeunes stades de brochet. Un approfondissement de ces travaux est envisagé dans différentes directions.

  2. Duplex real-time PCR method with internal amplification control for quantification of verrucosidin producing molds in dry-ripened foods. (United States)

    Rodríguez, Alicia; Córdoba, Juan J; Werning, María L; Andrade, María J; Rodríguez, Mar


    Verrucosidin, which is a tremorgenic mycotoxin responsible for neurological diseases, has been detected in different dry-ripened foods as consequence of the growth of toxigenic molds. To improve food safety, the presence of verrucosidin producing molds in these kind foods should be quantified. The aim of this study was to design a duplex real-time PCR (qPCR) protocol based on TaqMan methodology with an internal amplification control (IAC). Eleven verrucosidin producing and 11 non producing strains belonging to different species often reported in food products were used. Verrucosidin production was tested by micellar electrokinetic capillary electrophoresis (MECE) and high-pressure liquid chromatography-mass spectrometry (HPLC-MS). A primer pair (VerF1/VerR1) and a TaqMan probe (Verprobe) were designed from the SVr1 probe sequence of a verrucosidin producing Penicillium polonicum. The conserved regions of the β-tubulin gene were used to design primers (TubF1/TubR1) and probe (Tubprobe) of the non-competitive IAC. The functionality of the developed method was demonstrated by the high linear relationship of the standard curves which relating Ct values and DNA template of the tested verrucosidin producers using the verrucosidin and IAC primers. The ability to quantify verrucosidin producers of the developed TaqMan assay in all artificially inoculated food samples was successful, with a minimum detection limit of 1 log cfu per gram of food. This qPCR protocol including an IAC could be very useful to quantify verrucosidin producing molds in dry-ripened foods avoiding false negative results. This method should be proposed to monitor the target molds in HACCP programs to prevent the risk of verrucosidin formation and consequently avoid its presence in the food chain. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Shielded enclosure for handling radioactive material; Sorbonnes blindees pour manipulations radioactives

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, H.; Courouble, J.M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Two enclosures linked by an air-lock are described: they are designed for the safe handling of 5 curies 0.3 to 0.5 MeV {gamma} emitters, and each is composed of a semi-tight case, ventilated, clad in 80 mm steel plate, and suited for a wide variety of physics and chemistry operations. The equipment required for any given operation can be installed in the shortest possible time, access to the enclosure being via a removable front. Visual control is assured through a lead-glass screen. Each enclosure is fitted with a master-slave manipulator, Argon model 7, and plugs and air-locks are provided for the introduction of liquids and solids. (author) [French] On decrit deux enceintes reliees par un sas pour manipulation sur 5 curies d'emetteurs {gamma} de 0,3 a 0,5 MeV. Chacune des enceintes est constituee d'une boite semi-etanche, ventilee, entouree de toles d'acier de 80 mm. L'ensemble est concu pour y effectuer les operations physiques ou chimiques les plus variees. L'equipement necessaire a une manipulation donnee peut y etre installe dans le minimum de temps, l'acces se faisant par la face avant qui peut se deplacer. Une dalle de verre au plomb assure la vision. Chacune des sorbonnes est equipee d'une paire de telemanipulateurs Argonne modele 7. Des sas et des bouchons assurent le passage des solides et des fluides. (auteur)

  4. Coleridge e il Novecento italiano: Luzi, Fenoglio e Giudici traduttori della Rime of the Ancient Mariner

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    Laura Organte


    Full Text Available Questo lavoro propone un’analisi stilistica comparativa delle prime tre versioni “d’autore” novecentesche della Rime of the Ancient Mariner – quella di Mario Luzi (1949, quella di Beppe Fenoglio (1955, e quella di Giovanni Giudici (1987, con lo scopo di valutare i rapporti di forza che agiscono di volta in volta fra la tradizione letteraria del testo di partenza, quella della cultura di arrivo e gli idioletti dei traduttori. Verranno dunque messe a confronto in primo luogo le scelte – radicalmente diverse – adottate per trasporre il complesso e rigoroso meccanismo metrico della Rime, i suoi versi brevi e fortemente cadenzati e il fitto sistema delle rime e delle rispondenze foniche. In un secondo momento verrà esaminato l’atteggiamento di ciascun traduttore di fronte alla lingua, e la rassegna delle scelte lessicali sarà, infine, mirata a vagliare le tonalità utilizzate per rendere la difficile miscela messa a punto da Coleridge tra vocabolario poetico e «language really used by men».This paper provides a comparative stylistic analysis of the first three translations “d’autore” of the Rime of the Ancient Mariner published in Italy in the 20th century by Mario Luzi (1949, Beppe Fenoglio (1955 and Giovanni Giudici (1987. Such analysis aims to appraise the relationships acting in the translation process among the literary tradition of the original text, the Italian culture, and the translators’ idiolects. Therefore, the essay will compare the differences among the choices adopted to transpose the complex and rigorous metric mechanism of Coleridge’s Rime, the short and strongly rhythmic verses, and the dense system of rhymes and phonic correspondences. Secondly, the attitude of each translator will be addressed concerning the language, while the review of the lexical choices will finally aim to examine the tonalities deployed to convey the difficult mixture of poetic dictionary and “language really used by man”.

  5. Urologic surgery laparoscopic access: vascular complications. (United States)

    Branco, Anibal Wood


    Vascular injury in accidental punctures may occur in large abdominal vessels, it is known that 76% of injuries occur during the development of pneumoperitoneum. The aim of this video is to demonstrate two cases of vascular injury occurring during access in laparoscopic urologic surgery. The first case presents a 60-year old female patient with a 3cm tumor in the superior pole of the right kidney who underwent a laparoscopic partial nephrectomy. After the Verres needle insertion, output of blood was verified. During the evaluation of the cavity, a significant hematoma in the inferior vena cava was noticed. After the dissection, a lesion in the inferior vena cava was identified and controlled with a prolene suture, the estimated bloos loss was 300ml. The second case presents a 42-year old female live donor patient who had her right kidney selected to laparoscopic live donor nephrectomy. After the insertion of the first trocar, during the introduction of the 10mm scope, an active bleeding from the mesentery was noticed. The right colon was dissected and an inferior vena cava perforation was identified; a prolene suture was used to control the bleeding, the estimated blood loss was 200mL, in both cases the patients had no previous abdominal surgery. Urologists must be aware of this uncommon, serious, and potentially lethal complication. Once recognized and in the hands of experienced surgeons, some lesions may be repaired laparoscopically. Whenever in doubt, the best alternative is the immediate conversion to open surgery to minimize morbidity and mortality. Copyright® by the International Brazilian Journal of Urology.

  6. High speed pulsed magnetic fields measurements, using the Faraday effect; Mesures de champs magnetiques pulses rapides a l'aide de l'effet Faraday

    Energy Technology Data Exchange (ETDEWEB)

    Dillet, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    For these measures, the information used is the light polarization plane rotation induced by the magnetic field in a glass probe. This rotation is detected using a polarizer-analyzer couple. The detector is a photomultiplier used with high-current and pulsed light. In a distributed magnet (gap: 6 x 3 x 3 cm) magnetic fields to measure are 300 gauss, lasting 0.1 {mu}s, with rise times {<=} 35 ns, repetition rate: 1/s. An oscilloscope is used to view the magnetic field from the P.M. plate signal. The value of the field is computed from a previous static calibration. Magnetic fields from 50 to 2000 gauss (with the probe now used) can be measured to about 20 gauss {+-} 5 per cent, with a frequency range of 30 MHz. (author) [French] Pour faire de telles mesures, on utilise comme information la rotation du plan de polarisation de la lumiere provoquee par le champ magnetique dans une sonde en verre. On detecte cette rotation au moyen d'un polariseur et d'un analyseur, qui sont regles a 45 deg. pour conserver un phenomene lineaire. Le detecteur est un photomultiplicateur travaillant en fort courant en lumiere pulsee. Dans un aimant distribue d'entrefer 6 x 3 x 3 cm, on obtient des champs magnetiques a mesurer de 300 gauss, durant 0.1 {mu}s, avec des temps de montee {<=} 35 ns; au taux de 1 fois par seconde. L'observation du champ se fait sur oscilloscope a partir du signal de plaque du P.M. La valeur absolue du champ est obtenue au moyen d'un etalonnage statique prealable. On peut ainsi mesurer a 20 gauss et {+-} 5 pour cent pres environ des champs magnetiques de 50 a 2000 gauss (avec la sonde actuelle) et avec une bande passante de 30 MHz. (auteur)

  7. Copyright in the digital era: a pilot on behaviours, social perception and consciousness

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    Simone Aliprandi


    Full Text Available Questo paper illustra la predisposizione di una ricerca empirica condotta in occasione di una tesi di dottorato e fornisce un resoconto sommario dei risultati ottenuti. La ricerca è dedicata al tema “Il diritto d'autore nell'era digitale: comportamenti, percezione sociale e livello di consapevolezza” ed è stata condotta attraverso una web-survey disponibile online per la compilazione tra il febbraio e il giugno 2011. Nel paper si procederà dapprima a spiegare gli obbiettivi della ricerca e a presentare il questionario su cui è basata la survey. Si citeranno i principali nodi metodologici incontrati nella predisposizione della ricerca e i metodi utilizzati per la raccolta e l'analisi dei dati. Poi si renderà conto del numero totale delle risposte utili raccolte e della loro distribuzione per variabili demografiche (area geografica, età, titolo di studio, occupazione, tipologia di utenti. Si entrerà quindi nel cuore dei risultati raccolti, concentrandoci unicamente sui dati relativi allo Studio 1 – Italia, che denota la maggior rappresentatività delle risposte. Il commento dei dati raccolti (espressi in alcuni casi con l'ausilio di grafici a barre verrà condotto sulla base dei tre macro-temi della ricerca: comportamenti (ovvero come gli utenti della rete sono soliti acquisire contenuti creativi e software; opinioni e percezione (ovvero come gli utenti della rete si rapportano al problema del copyright, quali sono le loro opinioni e percezioni rispetto ai temi più caldi in materia; livello di consapevolezza (ovvero qual è l'effettivo livello di informazione e consapevolezza dei meccanismi di funzionamento del copyright da parte dei comuni utenti della rete e non degli “addetti ai lavori”.

  8. Dėl cirkumfleksinės metatonijos lietuvių kalbos dūriniuose

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    Danguolė Mikulėnienė


    Full Text Available ZUM PROBLEM DER ZIRKUMFLEXEN METATONIE IN LITAUISCHEN ZUSAMMEN­SETZUNGENZusammenfassungEs wird die Hypothese aufgestellt, daß die Metatonie in den litauischen Zusammensetzungen eine relativ späte Erscheinung ist, die bei der Umgestaltung des Paradigmas mit beweglichem Wortakzent entstanden ist, d. h. sie tauchte in der Zeit auf, als sich der Wortakzent in den Zusammensetzungen nach rechts verschob. Diese Annahme wird durch folgende Argumente bekräftigt: 1. Durch die im litauischen Schrifttum des 16. Jh. belegten Akzentuierungsvarianten, z. B. bei M. Daukša bedievỹs, -i und bediẽvis, -ė, svetimmóteris:svetimmotẽris; 2. Durch das Vorliegen der schwankenden Akzentuierung in den Zusammensetzungen der litauischen Sprache der Gegenwart – man tendiert dazu, den Akzent in Richtung der Morphemgrenze zu verrücken: jaunavedýs, aber auch jauñvedis; 3. Durch Fakten der lettischen Sprache, wo die Metatonie durch Verbreitung des Akuts in der entgegengesetzten Richtung zustande kam, vgl.: grūtdiẽnis ‘Armseliger’: dìena ‘Tag’.Obwohl sich die Akzentuierungssysteme der litauischen und lettischen Zusammensetzungen selbständig entwickelten, vollzog sich dieser Prozeß nach der Stimmbewegung auf Basis desselben bal­tischen modells:Es kann gefolgert werden, daß die in den litauischen Zusammensetzungen erscheinende Metato­nie, die als Ergebnis der Akzentverrückung anzusehen ist, funktionell mit der Verlegung des Akzents nach rechts während der Herausbildung der suffixalen Akzentuierung zusammenfällt.

  9. Il coraggio di essere sistemici: circolarità e riflessione nella pratica clinica in un contesto variamente culturale

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    Orietta Festa


    Full Text Available Nel presente articolo verrà presentata una ricerca condotta dalle autrici, volta a indagare gli aspetti specifici caratterizzanti la pratica terapeutica con i migranti. In particolare, attraverso il software ATLAS.ti, sono stati analizzati i trascritti di interviste condotte su otto terapeuti di differenti orientamenti teorici ma con esperienza di clinica con i migranti, al fine di individuare la frequenza di particolari codici attribuiti al testo. L’analisi di tali interviste si è avvalsa sia di un procedimento top down, partendo dalla teoria iniziale, sia di un processo bottom up, che implica un continuo ri-costruire le ipotesi sulla base delle scoperte fatte in fase di analisi. Dall'osservazione dei dati è emerso che, per quanto riguarda i contesti di intervento, sono stati nominati con la stessa frequenza contesti terapeutici e non; questi dati sono considerati dalle autrici una prova a favore del fatto che il lavorare con questo tipo di utenza richieda un cambiamento nella pratica clinica L’attenzione verte poi sui diversi tipi di setting: quello gruppale sembra essere considerato da tutti i terapeuti il più adatto con questo tipo di utenza; in relazione alla stessa emerge anche un nuovo livello di intervento, che coinvolge la sfera più spirituale. Dall’analisi degli strumenti, infine, viene evidenziato quello che dalle autrici è stato definito come il “Coraggio di essere sistemici”, cioè la necessità di estremizzare alcuni strumenti all’interno di contesti di lavoro con gli immigrati, portando alle potenzialità massime gli strumenti dell’approccio sistemico.

  10. Comparative Studies with N-Methyl-2-Pyrrolidone and Furfural As Solvents for Extraction of Lube Distillates Etude comparative de deux solvants, la n-methyl-2 pyrrolidone et le furfural, pour l'extraction de distillats pour huiles lubrifiantes

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    Krishna R.


    Full Text Available Solvent extraction of spindle raw lube distillate from Oman crude using n-methyl pyrrolidone (NMP containing 1. 5wt. % water has been studied using a six-stage all-glass mixer-settler. Results of three operating temperatures with NMP are reported. A 65-55°C extraction temperature appears to be most appropriate for this stock. Data obtained at this temperature have been compared with those for furfural on the basis of phase boundary curves, extraction and lube refining indices and selectivity. Comparison of the results shows NMP to be more selective as far as raffinate yield is concerned. It requires lower operating solvent-to-feed ratios and lower temperatures. On étudie dans cet article l'extraction par solvant de distillats bruts pour huiles lubrifiantes spindles au moyen de n-méthyl pyrrolydone (NMP contenant 1,5 % d'eau en poids, dans une unité en verre constituée par une batterie de six mélangeurs-décanteurs. On présente les résultats relatifs à trois températures de fonctionnement avec la NMP. Une température d'extraction de 66-55°C est celle qui convient le mieux pour cette huile de base. On compare les résultats obtenus à cette température avec ceux du furfural, en ce qui concerne les courbes de solubilité, les indices de raffinage et d'extraction, et les sélectivités. La comparaison des résultats montre que la NMP est plus sélective et conduit à un rendement de raffinat plus élevé. Elle nécessite des taux de solvant par rapport à la charge plus faibles ainsi que des températures d'extraction plus basses.


    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Billings, A.; Brinkman, K.; Marra, J.


    The Savannah River National Laboratory (SRNL) developed a series of ceramic waste forms for the immobilization of Cesium/Lanthanide (CS/LN) and Cesium/Lanthanide/Transition Metal (CS/LN/TM) waste streams anticipated to result from nuclear fuel reprocessing. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase ceramics containing hollandite-type phases, perovskites (particularly BaTiO{sub 3}), pyrochlores, zirconolite, and other minor metal titanate phases. Identification of excess Al{sub 2}O{sub 3} via X-ray Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) in the first series of compositions led to a Phase II study, with significantly reduced Al{sub 2}O{sub 3} concentrations and increased waste loadings. Three fabrication methodologies were used, including melting and crystallizing, pressing and sintering, and Spark Plasma Sintering (SPS), with the intent of studying phase evolution under various sintering conditions. XRD and SEM/EDS results showed that the partitioning of the waste elements in the sintered materials was very similar, despite varying stoichiometry of the phases formed. The Phase II compositions generally contained a reduced amount of unreacted Al{sub 2}O{sub 3} as identified by XRD, and had phase assemblages that were closer to the initial targets. Chemical composition measurements showed no significant issues with meeting the target compositions. However, volatilization of Cs and Mo was identified, particularly during melting, since sintering of the pressed pellets and SPS were performed at lower temperatures. Partitioning of some of the waste components was difficult to determine via XRD. SEM/EDS mapping showed that those elements, which were generally present in small concentrations, were well distributed throughout the waste forms. Initial studies of radiation damage tolerance using ion beam irradiation at Los

  12. Geodynamic and metabolic cycles in the Hadean

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    M. J. Russell


    interred in minerals such as ranciéite and hollandite in shallow marine manganiferous sediments, were sequestered and invaginated within the cyanobacterial precursor where, energized by light, they could oxidize water. Thus, a chemical sedimentary environment was required both for the emergence of chemosynthesis and of oxygenic photosynthesis, the two innovations that did most to change the nature of our planet.

  13. Petrogenesis of Variscan lamproites of the Bohemian Massif (United States)

    Krmíček, Lukáš; Romer, Rolf L.; Glodny, Johannes


    Paleozoic convergence of Laurussia and Gondwana-derived terranes with subduction of oceanic and continental crust of various compositions metasomatized the local mantle, a process which eventually led to a highly heterogeneous lithospheric mantle beneath the European Variscides. The eastern termination of the European Variscides (Moldanubian and Saxo-Thuringian zones of the Bohemian Massif in the Czech Republic, Austria, Germany, and Poland) is unusual as within a small area, the mantle had been modified by material from several subduction zones. Along the eastern border of the Bohemian Massif, mantle-derived dyke intrusions of peralkaline, perpotassic, and ultrapotassic compositions occur. The rocks are distinguished by mineral associations with K-amphibole and Fe-microcline and correspond mineralogically to a new variety of silica-rich lamproites. Lamproites from the Moldanubian Zone contain characteristic Ba-Ti-Zr accessory minerals (e.g., baotite, benitoite, hollandite), whereas lamproites from the Saxo-Thuringian Zone lack these minerals. Variscan lamproites from the Bohemian Massif sampled lithospheric mantle, whose chemical signature reflects extreme depletion (low CaO and Al2O3 contents) followed by strong metasomatic enrichment by material released from the subducted rocks, giving rise to crust-like trace element pattern, variably radiogenic Sr and unradiogenic Nd isotopic compositions, crustal Pb isotopic compositions, and a wide range of δ7Li ratios ranging from markedly positive to highly negative values. The metasomatic component is variably prominent in the lamproites, depending on the extent of partial melting, and the nature of the source of the metasomatic component. Preferential melting of the metasomatically enriched lithospheric mantle with stable K-amphibole resulted in lamproitic melts with very negative δ7Li values, which correlate positively with the peralkalinity, HFSE contents, and lower ɛNd of these rocks. Both, higher degree of

  14. Problemática de las pirolusitas de Ímini en la fabricación de ferromanganesos para aplicaciones metalúrgicas

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    Gómez-Pinilla, I.


    Full Text Available The possibility of eliminating lead impurities from the pyrolusite of Ímini (Morocco has been studied. The material undergoes a minerallurgical process which allows the separation of six fractions based on their differences in density and electromagnetic behaviour. Among the fifteen mineralogical species found, none of them contains lead in its theorical formulation. In order to detect the presence of this element the microanalysis by dispersive energies was used and a "mapping" of lead was made in each of the fractions. This element is concentrated in the psylomelane crystals. The chemical composition of the psylomelane was compared with that of the hollandite, taken from the references. The presence of lead inside the psylomelane crystalline structure avoids its separation by a classical minerallurgic of process and therefore the use of this material is not feasible for the production of ferromanganese.

    Se estudia la posibilidad de eliminar la impureza de plomo de la pirolusita de Ímini (Marruecos. El material se somete a un proceso mineralúrgico que permite separar seis fracciones basándose en su diferente densidad y comportamiento electromagnético. De las quince especies mineralógicas encontradas, ninguna incluye el plomo en su formulación teórica. Para detectar la presencia de este elemento se ha recurrido al microanálisis por dispersión de energías (EDX realizando un mapping de plomo en cada una de las fracciones. Este elemento se concentra en los cristales de psilomelana. La composición química de la psilomelana se ha comparado con la de una hollandita recogida de la bibliografía. La presencia del plomo la red de la psilomelana impide su separación por procedimientos mineralúrgicos convencionales y, por tanto, hace inviable la utilización de este material en la producción de ferromanganeso.

  15. Estimating Shock Pressures in Chondrites From High-Pressure Minerals in Shock-induced Melt Veins (United States)

    Xie, Z.; Sharp, T. G.


    High-pressure minerals are common in highly shocked (S6) L6 chondrites, occurring within or adjacent to shock-induced melt veins and melt pockets. They provide natural examples of high-pressure minerals that make up the Earth's transition zone (410 to 660 km depth) and lower mantle, as well as a record of high-pressure and temperature conditions during impact events on chondrite parent bodies. The high-pressure minerals that crystallize in melt veins and pockets can be used as an alternative means of investigating shock pressure. We used transmission electron microscopy (TEM) to characterize the shock-vein mineralogy in seven L6 chondrites ranging from shock stage S6 to S3: Tenham (S6), Umbarger (S6), Roy (S3-5), Ramsdorf (S4), Kunashak (S4), Nakhon Pathon (S4) and La Lande (S4). Tenham contains assemblages that reflect variable cooling rates during crystallization. Majorite plus magnesiow\\x81stite occur in the center of melt veins, whereas ringwoodite, akimotoite and round amorphous grains (probably vitrified MgSiO3-pervoskite) occur along melt-vein edges. In addition, a symplectitic intergrowth of majorite and an amorphous phase has been observed, which probably represents clinopyroxene that has disassociated into majorite plus CaSiO3-pervoskite. High pressure minerals in the Umbarger melt veins include: ringwoodite, akimotoite ((Mg,Fe)SiO3-ilmenite), augite, and hollandite-structured plagioclase. In addition, Fe2SiO4-spinel (new mineral) and stishovite occur in SiO2-FeO rich melt. High-pressure minerals in the Roy melt veins include ringwoodite and majorite. Melt veins in Ramsdorf, Kunashak, Nakhon Pathon and La lande contain fine-grained olivines and pyroxenes that are defect free and interpreted as having crystallized from the melt. Crystallization pressures can be inferred from the mineral assemblages in the melt veins and available phase equilibrium data. Melt veins in Tenham crystallized at pressure of approximately 25 GPa; Umbarger at pressure between 18

  16. Natural Occurrence of Fe2SiO4 - in Shocked Umbarger l6 Chondrite (United States)

    Xie, Z.; Sharp, T. G.


    Fe2SiO4 with the spinel structure was synthesized by Ringwood [1] and inferred to be important in Earth's upper mantle [1,2], but it has not previously been found in nature. Umbarger is an L6 chondrite, which contains a series of high-pressure phases: ring-woodite, akimotoite, augite and hollandite-structured plagioclase [3-6]. Transmission electron microscopy also revealed a Fe2SiO4-spinel and stishovite assem-blage in a Fe-rich zone of a melt pocket. Phyllosili-cates and glass are also associated with the Fe2SiO4-spinel, indicating post-shock aqueous glass alteration. The Fe2SiO4-spinel grains are equant to irregular, with sizes from 100 to 400 nm. Diffraction patterns can only be indexed as a spinel structure, but the unit cell is a little large (a= 8.46 Å) relative to synthetic Fe2SiO4-spinel (a=8.234 Å [1]). EDS analyses show that the spinel has a fayalite compositon with Fe/(Fe+Mg) ratio ranging from 62% to 97%. Stishovite occurs as elongated prismatic crystals up to 1 mm long and up to 100 mm wide. The alteration products in Umbarger are phyllosilicates rich in Fe and Si, with a basal layer spacing of about 9.7 Å. Crystallization of melt veins began with akimotoite and ringwoodite at pressures up to 25 GPa and ended with augite at pressure less than 18 GPa [3, 4]. Mg2SiO4-spinel and stishovite are stable in the pres-sure range from 15 GPa to 25 GPa in the enstatite-forsterite system [7], while Fe2SiO4-spinel and stishovite is stable at lower pressure. Fe2SiO4-spinel and stishovite assemblage, like that of Akimotoite plus ringwoodite, is a sub-solidus assemblage, indicating crystallization of a supercooled liquid during rapid cooling and decompression associated with shock pres-sure release. Reference: [1] Ringwood A.E. (1958) GCA,15, 18-29. [2] Irifune T. (1993) The Island Arc, 2, 55-71. [3] Xie Z. and Sharp T. G. (2000a) LPS XXXI, 2065.pdf. [4] Xie Z. and Sharp T. G. (2000b) MAPS, 35 A172. [5] Xie Z. et al.(2001) LPS XXXII, 1805.pdf. [6] Sharp T.G. (2001

  17. Anelasticity maps for acoustic dissipation associated with phase transitions in minerals (United States)

    Carpenter, Michael A.; Zhang, Zhiying


    Acoustic dissipation due to structural phase transitions in minerals could give rise to large seismic attenuation effects superimposed on the high temperature background contribution from dislocations and grain boundaries in the Earth. In addition to the possibility of a sharp peak actually at a transition point for both compressional and shear waves, significant attenuation might arise over wider temperature intervals due to the mobility of transformation twins or other defects associated with the transition. Attenuation due to structural phase transitions in quartz, pyroxenes, perovskites, stishovite and hollandite, or to spin state transitions of Fe2+ in magnesiowüstite and perovskite and the hcp/bcc transition in iron-nickel (Fe-Ni) alloy, are reviewed from this perspective. To these can be added possible loss behaviour associated with reconstructive transitions which might occur by a ledge mechanism on topotactic interfaces (orthopyroxene/clinopyroxene, olivine/spinel and perovskite/postperovskite), with impurities (Snoek effect) or with mobility of protons. There are experimental difficulties associated with measuring dissipation effects in situ at simultaneous high pressures and temperatures, so reliance is currently placed on investigation of analogue phases such as LaCoO3 for spin-state behaviour and LaAlO3 for the dynamics of ferroelastic twin walls. Similarly, it is not possible to measure loss dynamics simultaneously at the low stresses and low frequencies that pertain in seismic waves, so reliance must be placed on combining different techniques, such as dynamic mechanical analysis (low frequency, relatively high stress) and resonant ultrasound spectroscopy (high frequency, low stress), to extrapolate acoustic loss behaviour over wide frequency, temperature and stress intervals. In this context 'anelasticity maps' provide a convenient means of representing different loss mechanisms. Contouring of the inverse mechanical quality factor, Q-1, can be

  18. Silver-Containing α-MnO2 Nanorods: Electrochemistry in Na-Based Battery Systems. (United States)

    Huang, Jianping; Poyraz, Altug S; Lee, Seung-Yong; Wu, Lijun; Zhu, Yimei; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S


    Manganese oxides are considered attractive cathode materials for rechargeable batteries due to the high abundance and environmental friendliness of manganese. In particular, cryptomelane and hollandite are desirable due to their ability to host cations within their octahedral molecular sieve (OMS-2) α-MnO2 structure. In this work, we investigate silver containing α-MnO2 structured materials (AgxMn8O16, x = 1.22, L-Ag-OMS-2 or 1.66, H-Ag-OMS-2) as host materials for Li ion and Na ion insertion/deinsertion. The results indicate a significant difference in the lithiation versus sodiation process of the OMS-2 materials. Initial reduction of Ag1.22Mn8O16 to 1.0 V delivered ∼370 mAh/g. Cycling of Ag1.22Mn8O16 between voltage ranges of 3.8-1.7 V and 3.8-1.3 V in a Na battery delivered initial capacities of 113 and 247 mAh/g, respectively. In contrast, Ag1.66Mn8O16 delivered only 15 mAh/g, ∼ 0.5 electron equivalents, to 1.7 and 1.3 V. Study of the system by electrochemical impedance spectroscopy (EIS) showed a significant decrease in charge transfer resistance from 2029 Ω to 594 Ω after 1.5 electron equivalents per Ag1.22Mn8O16 formula unit of Na ion insertion. In contrast, both Ag1.22Mn8O16 and Ag1.66Mn8O16 exhibited gradual impedance increases during lithiation. The formation of silver metal could be detected only in the sodiated material by X-ray diffraction (XRD). Thus, the impedance of Ag-OMS-2 decreases upon sodiation coincident with the formation of silver metal during the discharge process, consistent with the more favorable formation of silver metal during the sodiation process relative to the lithation process.

  19. The Controversial Role of Inter-diffusion in Glass Alteration

    Energy Technology Data Exchange (ETDEWEB)

    Gin, Stephane; Neill, Lindsay; Fournier, M.; Frugier, Pierre; Ducasse, T.; Tribet, M.; Abdelouas, Abdessalam; Parruzot, Benjamin; Neeway, James J.; Wall, Nathalie


    Current kinetic models for nuclear waste glasses (e.g. GM2001, GRAAL) are based on a set of mechanisms that have been generally agreed upon within the international waste glass community. These mechanisms are: hydration of the glass, ion exchange reactions (the two processes are referred as inter-diffusion), hydrolysis of the silicate network, and condensation/precipitation of partly or completely hydrolyzed species that produces a porous and amorphous layer and crystalline phases on surface of the altered glass. Recently, a new idea with origins in the mineral dissolution community has been proposed that excludes inter-diffusion process as a potential rate-limiting mechanism. To understand how the so-called interfacial dissolution/precipitation model can change the current understanding of glass behavior, a key experiment used to account for this model was replicated to further revisit the interpretation. This experiment was performed at 50°C, with SON68 glass, in static mode, deionized water and S/V ratio of 10 m-1 for 6 months. It turn out that glass alters in an intermediate kinetic regime between the forward and the residual rate. According to previous and new solid characterizations, it is concluded that neither a simple inter-diffusion model nor the interfacial dissolution precipitation model can account for the observed elemental profiles within the alteration layer. More generally, far and close-to-saturation conditions must be distinguished and literature provides evidences that inter-diffusion takes place in slightly acidic conditions and far from saturation. However, closer to saturation, when a sufficiently dense layer is formed, a new approach is proposed requiring a full description of chemical reactions taking place within the alteration layer and involving water molecules as it is thought that water accessibility to the pristine glass is the rate-limiting process.

  20. Argon Cluster Sputtering Source for ToF-SIMS Depth Profiling of Insulating Materials: High Sputter Rate and Accurate Interfacial Information

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaoying; Liu, Bingwen; Zhao, Evan; Jin, Ke; Du, Yingge; Neeway, James J.; Ryan, Joseph V.; Hu, Dehong; Zhang, Hongliang; Hong, Mina; Le Guernic, Solenne; Thevuthasan, Suntharampillai; Wang, Fuyi; Zhu, Zihua


    For the first time, the use of an argon cluster ion sputtering source has been demonstrated to perform superiorly relative to traditional oxygen and cesium ion sputtering sources for ToF-SIMS depth profiling of insulating materials. The superior performance has been attributed to effective alleviation of surface charging. A simulated nuclear waste glass, SON68, and layered hole-perovskite oxide thin films were selected as model systems due to their fundamental and practical significance. Our study shows that if the size of analysis areas is same, the highest sputter rate of argon cluster sputtering can be 2-3 times faster than the highest sputter rates of oxygen or cesium sputtering. More importantly, high quality data and high sputter rates can be achieved simultaneously for argon cluster sputtering while this is not the case for cesium and oxygen sputtering. Therefore, for deep depth profiling of insulating samples, the measurement efficiency of argon cluster sputtering can be about 6-15 times better than traditional cesium and oxygen sputtering. Moreover, for a SrTiO3/SrCrO3 bi-layer thin film on a SrTiO3 substrate, the true 18O/16O isotopic distribution at the interface is better revealed when using the argon cluster sputtering source. Therefore, the implementation of an argon cluster sputtering source can significantly improve the measurement efficiency of insulating materials, and thus can expand the application of ToF-SIMS to the study of glass corrosion, perovskite oxide thin films, and many other potential systems.

  1. Pore-Level Investigation of Heavy Oil Recovery using Steam Assisted Gravity Drainage (SAGD Étude à l’échelle des pores de la récupération d’huiles lourdes par drainage gravitaire assisté par injection de vapeur (SAGD

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    Mohammadzadeh O.


    entrapment of steam due to the capillarity followed by condensation, steam condensation at the interface due to temperature gradient, and snap-off of liquid films are also illustrated using glass micromodels in pore-level visualization experiments. L’application réussie du procédé de drainage gravitaire assisté par injection de vapeur à l’aide de puits horizontaux lors de divers essais de champ, essentiellement au Canada, montre qu’on peut atteindre un taux de récupération élevé et des rapports vapeur injectée/pétrole récupéré économiquement viables. Le procédé de récupération par SAGD a été développé sur le plan théorique, testé sur pilote et commercialisé, tout cela au Canada; il reste cependant encore plusieurs problèmes techniques à résoudre dans ce procédé. Les phénomènes qui se développent à l’échelle des pores lors de la récupération d’huiles lourdes à l’aide du procédé SAGD ne sont pas encore très bien compris, ce qui conduit à intégrer la physique du processus au niveau des pores dans des modèles mathématiques. L’étude à l’échelle des pores des phénomènes physiques concernant la distribution des fluides et les types d’écoulement dans le milieu poreux dans ce procédé devrait apporter une nette amélioration de la compréhension des phénomènes macroscopiques observés aussi bien en laboratoire que sur le terrain. L’objectif principal de cet article est l’étude visuelle et la description des phénomènes à l’échelle des pores par l’utilisation d’un micromodèle en verre. Des expériences de SAGD ont été effectuées au laboratoire sur des micromodèles de réseaux capillaires gravés sur des plaques de verre qui, au départ, ont été saturés d’huile lourde. Ces expériences furent réalisées dans une chambre à vide pour éviter des pertes de chaleur excessives vers l’extérieur. Les premiers résultats montrent que lorsque l’interface huile lourde/vapeur est établie, un

  2. Dinamiche di manipolazione mentale ed organizzazioni di stampo mafioso / Dynamiques de manipulation mentale et organisations criminelles de type mafieux / Dynamics of mental manipulation and Mafia groups

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    Pomilla A.


    Full Text Available Questo articolo si focalizza sull’analisi delle dinamiche di manipolazione mentale che i gruppi mafiosi esercitano sui propri affiliati, in grado di determinare progressivi vincoli morali non già in virtù delle attività criminose che verranno poi svolte, bensì in relazione alle rappresentazioni mentali che gli stessi hanno verso di sé in quanto appartenenti a tale gruppo. Verranno quindi descritte le rappresentazioni mentali che gli affiliati hanno di se stessi, nonché quelle provenienti dalle disamine interpretative esterne. Verrà inoltre illustrato il “pensiero mafioso” quale profonda ed inconscia modalità ideativa che caratterizza il “gruppo mafia” con valori più saldi e forti di quelli familiari ed in virtù della quale si determinano proprio quei meccanismi di svincolo morale che sostanziano la dimensione criminologica delle organizzazioni di stampo mafioso.Cet article se concentre sur l'analyse des dynamiques de manipulation mentale que les groupes mafieux exercent sur leurs affiliés, des dynamiques capables de susciter un désinvestissement moral progressif, non pas lié aux activités criminelles qui seront développées par la suite, mais en relation avec les représentations mentales que les individus ont d’eux-mêmes, en tant que membres d’un tel groupe. Ainsi, nous décrirons les représentations mentales que les membres ont d’eux-mêmes, ainsi que celles tirées des analyses interprétatives externes. De plus, nous illustrerons « la pensée mafieuse » en tant que modalité idéative profonde et inconsciente qui caractérise « le groupe mafieux » marqué (et soudé par des valeurs plus solides et plus fortes que celles issues du milieu familial et grâce auxquelles se déterminent ces mécanismes de désinvestissement moral qui caractérisent la dimension criminologique des organisations de type mafieux.This article analyses the dynamics of mental manipulation that the Mafia groups impose on their own

  3. Borges, Ariosto e la vita segreta dei personaggi minori

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    Marco Dorigatti


    Full Text Available Inteso quale omaggio a Emilio Bigi, sia pure indiretto, lo studio prende spunto da un’intervista, tuttora inedita, rilasciata nel 1984 dallo scrittore argentino Jorge Luis Borges, in cui aveva citato, credendoli ariosteschi, dei versi che per lui, giunto in età ormai avanzata, erano diventati, più che un motto, una metafora di vita. Poco importa che, come verrà chiarito vagliando la loro storia e le relative fonti, quei versi, facenti capo alla misteriosa figura di un personaggio saraceno, Alibante di Toledo, in realtà appartenessero all’officina poetica di Francesco Berni: essi vengono ciò nondimeno assunti quale filo conduttore per un percorso esplorativo all’interno dell’Orlando furioso che ne vaglia la valenza per così dire “ariostesca”, giusta la reminiscenza borgesiana. Approdata infine a Cervantes, la discussione si conclude facendo ritorno a Borges e misurando l’impatto che quei medesimi versi hanno avuto sulla sua propria opera poetica.Intended as a heartfelt tribute to Emilio Bigi, albeit an indirect one, this essay draws on an interview, still unpublished, given by Argentine writer Jorge Luis Borges in 1984, in which he quoted a couple of lines of poetry which he firmly believed to be by Ariosto, and which for him, by then an old man, had become, more than a motto, a metaphor of life. It does not really matter that, as will become apparent retracing their history as well as their sources, these lines, centring on the mysterious figure of a Saracen character called Alibante of Toledo, actually belonged to Francesco Berni: they are here assumed as the main motif to be explored within Orlando furioso, in order to ascertain to what extent their nature may be regarded to be Ariostan, just as Borges thought. Having finally reached Cervantes, the discussion concludes by returning once more to Borges and considering the impact that these lines, which had remained engrained in his memory throughout his life, had on his own

  4. Fluid Displacement Efficiency in Layered Porous Media. Mobility Ratio Influence Efficacité de déplacement de fluides en milieu poreux stratifié. Influence du rapport de mobilité

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    Wright R. J.


    Full Text Available Important effects of petroleum reservoir stratification upon chemical enhanced oil recovery processes have been modelled using systems containing layers of two different permeabilities. Experimentally, visual models composed of glass bead packings have been exploited and miscible matched-density displacements performed. The results show a strong sensitivity to fluid mobility ratio. Flow pattern observation and mathematical analysis have shown that complex viscous crossflow processes are very influential. We present a non-empirical mathematical model for dual layer systems. Our calculation of crossflow effects using this analytical method compares favourably with experimental results from varions sources. Finally, we show how to apply this model to multilayer cross-sectional and three-dimensional problems. Des effets majeurs de la stratification de réservoirs pétroliers sur les procédés chimiques de récupération assistée du pétrole ont été modélisés au moyen de systèmes comprenant des couches à deux perméabilités différentes. Pour l'approche expérimentale, nous avons eu recours à des modèles d'observation composés de billes de verre où des déplacements de fluides miscibles de densités ajustées ont été réalisés. Les résultats indiquent une forte sensibilité au rapport de mobilité des fluides. L'observation du schéma d'écoulement et son analyse mathématique ont montré que des phénomènes d'écoulement visqueux interbancs ont une très grande influence. Nous présentons un modèle mathématique non empirique de systèmes à double couche. Nos calculs des effets des écoulements transversaux avec des méthodes analytiques sont bien vérifiés par les résultats expérimentaux provenant de sources diverses. Nous montrons enfin comment appliquer ce modèle à des problèmes à plusieurs bancs avec échanges entre couches et à trois dimensions.

  5. Quando lo Spirito Paracleto sarà venuto, „convincerà il mondo quanto al peccato, alla giustizia e al giudizio” (Gv 16, 8

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    Tomasz Maria Dąbek


    Full Text Available La misericordia di Dio è immensa, ma Dio aspetta la risposta dell’uomo libero. Molto importante è il riconoscimento del peccato e la coscienza del bisogno dell’aiuto divino, della grazia. Lo Spirito Consolatore (παράκλητος, quando verrà, mostra di nuovo la necessità della conversione, della preparazione al giudizio finale. Il “mondo” nel Vangelo di Giovanni designa tutta la creatura, il mondo materiale, ma anche la gente opposta a Dio. Il „principe di questo mondo” (possibile un senso ironico – cf. Gv 12, 31; 14, 30; 16, 11 è il diavolo. Lo Spirito „convincerà il mondo quanto al peccato, alla giustizia e al giudizio”. Il verbo „convincerà” rende il termine greco ἐλέγξει (cf. Gv 8, 46; 1 Cor 14, 24, che nel Nuovo Testamento può significare anche „correggere” (cf. Mt 18, 15, „riprendere” (cf. Lc 3, 19; 1 Tm 5, 20; 2 Tm 4, 2; Tt 1, 13; 2, 15; Ebr 12, 5; Ap 3, 19, „condannare” (Gv 3, 20; Ef 5, 11. 13; Gc 2, 9; „confondere” (Tt 1, 9; Gd 15. Il nome παράκλησις spesso si traduce come „consolazione” (cf. At 4, 36; 2 Cor 1, 3s; 7, 4, ma anche „esortazione” (cf. At 13, 15; 15, 31; Rm 12, 8; 1 Tm 4, 13, che può essere forte e scoprire i difetti degli esortati. Il peccato (la bestemmia contro lo Spirito (cf. Mt 12, 31s; Mc 3, 28ss; Lc 12, 10 ha luogo quando l’uomo rifiuta l’ispirazione di Dio, rigetta la testimoniaza di Gesù confermata dai segni della potestà divina (cf. Gv 15, 22-25; Mc 1, 22. 27; Lc 4, 32. 36; Mt 7, 28. I peccatori devono convertirsi, vivere nella vita nuova con il Cristo risorto nella forza dello Spirito (cf. Rm 6, 1-7. 13s; 1 Cor 15, 17; 2 Cor 12, 21; Gal 5, 1; 1 Tm 5, 20. 22. 24s; 1 Gv 1, 8-10. Quella è l’unica via per ciascuno che vive nel mondo, nel quale ancora opera il diavolo, ma per il quale il Dio Padre ha mandato il suo Figlio come Salvatore (cf. 1 Gv 4, 14; 4, 9; Gv 3, 16.

  6. Impact of nutrition since early life on cardiovascular prevention

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    Guardamagna Ornella


    nutrizione svolge un ruolo preventivo fondamentale sin dall’epoca prenatale e nelle diverse età della crescita. La condizione metabolica e neuro-endocrino cui è sottoposto il feto è rilevante per la “programmazione metabolica”. E’ dimostrata inoltre l’importanza delle modalità di allattamento e divezzamento con particolare interesse per l’assunzione di proteine nel controllo dei fattori di rischio cardiovascolari. La corretta distribuzione di macronutrienti (lipidi, proteine e carboidrati dall’infanzia all’adolescenza favorisce una crescita corretta e risulta utile a prevenire l’insorgenza dei determinanti di rischio di malattia cardiovascolare in età adulta. Nella presente review verrà esaminato l’impatto della nutrizione dalle più precoci fasi delle vita sul rischio cardiovascolare.

  7. Les milieux extrêmes. Journées d'études du CESTA, Paris, 4-5 octobre 1983 Extreme Environments. Cesta Conference, Paris, 4-5 October 1983

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    Bertrand A. R. V.


    Full Text Available Ces journées d'études étaient consacrées aux problèmes impliqués par l'exploration et l'exploitation des milieux extrêmes. On n'a pas cherché à approfondir la notion de milieu extrême mais à en étudier trois principaux : l'espace, les grands fonds marins, les enceintes soumises à de forts rayonnements nucléaires, à travers quatre thèmes de problèmes communs : la robotique, la sécurité, les matériaux et l'intervention humaine. Cette réunion a mis en évidence : - le dilemme constitué par la nécessité d'assurer d'une part la sécurité de la population par l'emploi de techniques fiables donc éprouvées et d'autre part le progrès scientifique dont les techniques nouvelles peuvent être fiables sans être encore éprouvées ; - l'emploi généralisé de la robotique (soudage sous-marin profond, engin submersible non habité à intelligence artificielle. . . ; - la création de matériaux nouveaux (composites à matrice métallique, fibres optique en verre chloré, lubrifiant opérant sous vide. . . - la mise au point de méthodes nouvelles pour l'analyse probabiliste des risques. This conference concentrated on the problems raised by the exploration and productive use of extreme environments. No effort was made to define the concept of an extreme environnent, but three specific ones were considered: space, great sea depths, enclosures subjected Io intense nuclear radiation. There were four topics covering problems encountered in such environments: robotics, safety, materials and human intervention. This meeting brought out the following points: - The dilemma brought on by the need to ensure part of the safety of the population by using reliable, hence proven, techniques at the saure time as scientific progress in which new techniques may be reliable without yet being proven. - The generalized use of robotics (deep subsea welding, unmanned submersible with artificial intelligence, etc. . - The creation of new materials

  8. Study of alkaline-earth element complexes in anhydrous acetic acid; Etude de complexes des elements alcalino-terreux dans l'acide acetique anhydre

    Energy Technology Data Exchange (ETDEWEB)

    Petit, N. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Institut National des Sciences et Technique Nucleaires, Saclay (France)


    We have studied the complexes of alkaline-earth elements in anhydrous acetic acid. Using glass-electrode potentiometry we have studied the titration of alkaline earth acetates with perchloric acid which is the strongest acid in anhydrous acetic acid. These titrations have shown that the basic strength of these acetates increases as follows: Mg < Ca < Si < Ba. The interpretation of the titration curves has made it possible to determine a certain number of reaction constants. A study has also been made of the dissociation, of alkaline earth perchlorates formed during these titrations, since the determination of the reaction constants involves their dissociation constants. During this work it has been possible to show that barium has a particular behaviour, giving a mixed compound (a lower acetate complex) not only in the presence of perchloric acid but also in the presence of sulfuric and hydrochloric acids. These are respectively: the mixed acetate-perchlorate complex of barium: Ba(OAc) (ClO{sub 4}); the mixed acetate-acid sulfate complex of barium: Ba (OAc)(HSO{sub 4}); the mixed acetate-chloride of barium: Ba (OAc)(Cl). (author) [French] Nous nous sommes interesses a l'etude de complexes des elements alcalino-terreux dans l'acide acetique anhydre. Par potentiometrie avec une electrode de verre, nous avons etudie les titrages des acetates alcalino-terreux par l'acide perchlorique, qui est l'acide le plus fort dans l'acide acetique anhydre. Ces titrages ont montre que la force basique de ces acetates croit selon: Mg < Ca < Sr < Ba. L'interpretation des courbes de titrages a permis la determination d'un certain nombre de constantes de reactions. D'autre part, nous avons etudie la dissociation des perchlorates alcalino-terreux formes au cours de ces titrages car leurs constantes de dissociation interviennent dans la determination des constantes de reactions. Au cours de ce travail, nous avons pu mettre en evidence le

  9. Thermic decomposition of biphenyl; Decomposition thermique du biphenyle

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    Liquid and vapour phase pyrolysis of very pure biphenyl obtained by methods described in the text was carried out at 400 C in sealed ampoules, the fraction transformed being always less than 0.1 per cent. The main products were hydrogen, benzene, terphenyls, and a deposit of polyphenyls strongly adhering to the walls. Small quantities of the lower aliphatic hydrocarbons were also found. The variation of the yields of these products with a) the pyrolysis time, b) the state (gas or liquid) of the biphenyl, and c) the pressure of the vapour was measured. Varying the area and nature of the walls showed that in the absence of a liquid phase, the pyrolytic decomposition takes place in the adsorbed layer, and that metallic walls promote the reaction more actively than do those of glass (pyrex or silica). A mechanism is proposed to explain the results pertaining to this decomposition in the adsorbed phase. The adsorption seems to obey a Langmuir isotherm, and the chemical act which determines the overall rate of decomposition is unimolecular. (author) [French] Du biphenyle tres pur, dont la purification est decrite, est pyrolyse a 400 C en phase vapeur et en phase liquide dans des ampoules scellees sous vide, a des taux de decomposition n'ayant jamais depasse 0,1 pour cent. Les produits provenant de la pyrolyse sont essentiellement: l' hydrogene, le benzene, les therphenyles, et un depot de polyphenyles adherant fortement aux parois. En plus il se forme de faibles quantites d'hydrocarbures aliphatiques gazeux. On indique la variation des rendements des differents produits avec la duree de pyrolyse, l'etat gazeux ou liquide du biphenyle, et la pression de la vapeur. Variant la superficie et la nature des parois, on montre qu'en absence de liquide la pyrolyse se fait en phase adsorbee. La pyrolyse est plus active au contact de parois metalliques que de celles de verres (pyrex ou silice). A partir des resultats experimentaux un mecanisme de


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    Marta Damato


    Full Text Available L’articolo si propone di mettere in luce alcuni aspetti sintattici della lingua usata da Camillo Golgi, medico e ricercatore, nonché Premio Nobel 1906 per la Medicina o la Fisiologia, per come si offrono nella sua produzione epistolare ufficiale e privata.In prima istanza verrà fornita una duplice contestualizzazione dell’analisi linguistica da condurre: si descriverà la scrittura epistolare come genere peculiare, sia per la sua particolare collocazione al crocevia della diamesia (tra scritto e parlato, sia in relazione alla cosiddetta grammatica epistolare; in seguito, si presenterà la figura purtroppo ancora poco nota di Camillo Golgi, con tutti i suoi meriti scientifici e con l’auspicio di una sua riscoperta. Poi si giungerà alla vera e propria analisi linguistica, che verterà, come si è scritto, sulla sintassi delle lettere golgiane: l’analisi farà emergere la parziale adesione dello scrivente al canone dell’epistolografia, mettendo anche in luce alcuni scarti rispetto a questo, scarti collegati a precise scelte del Golgi che si allontanano dal parlato tipicamente riprodotto nella comunicazione epistolare, in direzione di un modello scritto formale e controllato, rispondente, in particolare, alle modalità espressive tipiche della prosa scientifica e della lingua della burocrazia. The syntax of Camillo Golgi’s letters: epistolary grammar, the language of science and bureaucracy The article intends to illustrate some prominent syntactical aspects of the language used by Camillo Golgi, researcher and famous doctor, winner of the Nobel Prize for Medicine and Physiology in 1906, as these aspects appear in his official and private correspondence. First the context of the linguistic analysis will be explained. Epistolary writing is a particular genre, halfway between written and spoken language, featuring a special grammar. Then the little-known figure of Camillo Golgi, with his many scientific merits, will be presented and

  11. Entraînement de globules d'huile par un tensio-actif. Etude de la formation du banc Mobilization of Oil Ganglia by a Surfactant Analysis of Bank Formation

    Directory of Open Access Journals (Sweden)

    Moulu J. C.


    Full Text Available Lors de l'injection d'une solution de tensio-actif dans un gisement déjà balayé par de l'eau, l'huile résiduelle, piégée sous la forme de globules discontinus, est remise en mouvement et se regroupe éventuellement sous la forme d'un banc d'huile. Le but de la présente étude est d'expliquer la formation de ce banc au cours d'un tel déplacement. Les résultats d'expériences réalisées en micromodèles de billes de verre permettent de constater que : - la récupération globale est corrélable avec le nombre capillaire Nc= uVdf/O, u et Vdf étant la viscosité et la vitesse de Darcy du fluide injecté, O la tension interfaciale avec l'huile en place ; - la vitesse des globules varie différemment avec u, Vdf, O et tend vers la même limite plus grande que la vitesse du fluide injecté pour de grandes valeurs du nombre capillaire Nc ; - le banc d'huile ne se forme que dans le cas où la vitesse des globules atteint celle du fluide injecté. L'huile déplacée reste alors groupée avec une saturation importante au niveau du front de tensio-actif. When a surfactant solution is injected into a reservoir previously waterflooded, the residual oil trapped as discontinuous ganglia is mobilized and eventually bunched together forming an oil bank. The aim of this study is to explain the formation of this bank during such a drive. The results of experiments performed in micromodels of glass beads show that: a Overall recovery can be correlated with the capillary number, Nc = uVfd/O, in which u and Vfd are the viscosity a and Darcy velocity of the injected fluid and O is the interfacial tension with the oil in place. b Ganglia velocity varies differently with u, Vfd and O, and it tends towards the same limit faster than the velocity of the injected fluid for high values of the capillary number Nc. c The oil bank is formed only in the case where globule velocity attaints that of injected fluid. the dispaced oil then remains bunched, with high

  12. Initial experience with laparoscopic single-incision triangulated umbilical surgery (SITUS) in simple and radical nephrectomy. (United States)

    Nagele, Udo; Walcher, Ute; Herrmann, Thomas R W


    New transumbilical laparoendoscopic procedures are an emerging field in urologic surgery. We introduced the concept of single-incision triangulated umbilical surgery (SITUS) in 2009. SITUS technique uses straight optics and instruments in a triangulated fashion via three trocars placed through an umbilical incision resulting in a familiar laparoscopic environment. Aim of the study was to demonstrate the feasibility of SITUS in simple and radical nephrectomy in daily routine. From October 2009 to July 2010, in 3 patients with cirrhotic kidneys a simple and in 12 patients a radical nephrectomy was performed in SITUS technique. The umbilical fold was incised at three-fourth of its circumference; in the patient with radical nephrectomy, additionally small "c"-shaped skin flaps were removed. After achieving a pneumoperitoneum by Verres technique, a 5-mm camera port and then a cranial 5 mm and a caudal 11 mm working trocar were placed with at a distance of 5-10 cm with the aid of two Langenbeck hooks, thus allowing triangulation except in the radical nephrectomy patients, where an 11-mm caudal trocar (Endopath, Ethicon, Hamburg, GER) was used. Using long conventional laparoscopic instruments, En-Seal pressure coagulator and dissector (Erbe, Tuebingen, Germany), Hem-O-Lock clips (Weck, Teleflex, USA), and a 30° 5-mm optic (Karl Storz, Tuttlingen, GER), the interventions were executed like conventional laparoscopic transperitoneal procedures. OR time was mean 127 min [120, 153] for cirrhotic kidney nephrectomy group and mean 137 min [91, 185] in the radical nephrectomy group. Mean hemoglobin drop was 1.5 g/dl [1.2, 1.7] in benign cases and 2.4 [1.1, 4.9] in radial nephrectomies. All except one diabetic patient with wound infection had an uneventful follow-up without postoperative complications. The patients were discharged at postoperative day 5 [3, 29]. SITUS technique for simple and radical nephrectomy is an attractive alternative to conventional laparoscopy and single

  13. Vibrations et relaxations dans les molécules biologiques. Apports de la diffusion incohérente inélastique de neutrons (United States)

    Zanotti, J.-M.


    Le présent document ne se veut pas un article de revue mais plutôt un élément d'initiation à une technique encore marginale en Biologie. Le lecteur est supposé être un non spécialiste de la diffusion de neutrons poursuivant une thématique à connotation biologique ou biophysique mettant en jeu des phénomènes dynamiques. En raison de la forte section de diffusion incohérente de l'atome d'hydrogène et de l'abondance de cet élément dans les protéines, la diffusion incohérente inélastique de neutrons est une technique irremplaçable pour sonder la dynamique interne des macromolécules biologiques. Après un rappel succinct des éléments théoriques de base, nous décrivons le fonctionnement de différents types de spectromètres inélastiques par temps de vol sur source continue ou pulsée et discutons leurs mérites respectifs. Les deux alternatives utilisées pour décrire la dynamique des protéines sont abordées: (i)l'une en termes de physique statistique, issue de la physique des verres, (ii) la seconde est une interprétation mécanistique. Nous montrons dans ce cas, comment mettre à profit les complémentarités de domaines en vecteur de diffusion et de résolution en énergie de différents spectromètres inélastiques de neutrons (temps de vol, backscattering et spin-écho) pour accéder, à l'aide d'un modèle physique simple, à la dynamique des protéines sur une échelle de temps allant d'une fraction de picoseconde à quelques nanosecondes.

  14. Incontri e riflessioni con studentesse universitarie in Europa / Rencontres et réflexions avec des étudiantes universitaires en Europe / Meetings and reflections with European female university students

    Directory of Open Access Journals (Sweden)

    Sette Raffaella


    Full Text Available Con riferimento alla ricerca europea “Gender-Based Violence, Stalking and Fear of Crime – Prevention and Intervention”, nell’articolo vengono messi a confronto alcuni dati ricavati dalla somministrazione di un questionario a studentesse di 34 università ubicate in Germania, Inghilterra, Italia, Polonia e Spagna. In particolare, ci si soffermerà su aspetti relativi alle difficoltà riscontrate nel riconoscere la violenza e al raccontarla ad altri e su caratteristiche dell’esperienza subìta.Infine, verrà focalizzata l’attenzione su alcune tematiche che si collegano all’identificazione di buone prassi per prevenire ed intervenire in casi di violenza di genere a danno di studentesse universitarie. RésuméEn référence à la recherche européenne “Gender-Based Violence, Stalking and Fear of Crime – Prevention and Intervention”, dans cet article, l’auteur analyse des données provenant d’un questionnaire soumis aux étudiantes de 34 universités situées en Allemagne, en Angleterre, en Italie, en Pologne et en Espagne. L’auteur se concentre tout particulièrement sur certains aspects liés aux difficultés rencontrées pour reconnaître la violence et pour la raconter aux autres, et sur certaines caractéristiques de l’expérience vécue. Enfin, l’auteur concentre son attention sur les bonnes pratiques à adopter pour prévenir la violence de genre infligée aux étudiantes universitaires et intervenir contre celle-ci.AbstractReferring to the European research “Gender-Based Violence, Stalking and Fear of Crime – Prevention and Intervention”, in this article the author will compare some data gathered from a questionnaire carried out among female students of 34 universities situated in Germany, England, Italy, Poland and Spain. In particular, the author will dwell on some aspects related to difficulties in recognizing violence, disclosing this experience, and on some characteristics of it.In conclusion, the

  15. Study of various processes for marking sediments with gold-198; Etude de divers procedes de marquages de sediments par l'or 198

    Energy Technology Data Exchange (ETDEWEB)

    Jeanneau, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    The use of radioactive isotopes for the study of sediment deposits is based mainly on two methods: marking in the mass - a glass of an element which can be activated replaces the sediment; surface marking - a physico-chemical process is used to deposit a radio-element at the surface of the sediment. The second process is used in particular for sands when it is advantageous to have a large number of particles for statistical analysis. The aim of this work was to develop a rapid and simple method of marking which could be applied on the actual site of the experiment where equipment, may be limited. The method recommended for marking sand with gold-198 is a combination of the Petersen (treatment with tin chloride) and Campbell (treatment with silver) methods combined with prior treatments with nitric acid and caustic soda. Using this method it is possible to deposit 125 mg of gold per kilo of sediment with a yield of 95 per cent (i.e. 10 Ci/kg) using a hydrochloric acid solution containing gold. The problem of the solidity of the deposits, of their value and of their reproducibility is discussed from the point of view of the mineral constitution of the sand. (author) [French] L'utilisation d'isotopes radioactifs pour l'etude des deplacements sedimentaires fait, principalement appel a deux methodes: le marquage massique - un verre contenant un element activable remplace le sediment; le marquage superficiel - un traitement physico-chimique permet de deposer un radioelement a la surface du sediment. Le second procede est surtout employe pour les sables lorsqu'il est utile de disposer d'un grand nombre de grains pour des raisons statistiques. Le but de ce travail etait de mettre au point une methode simple et rapide de marquage pouvant etre appliquee sur le site meme de l'experience pour les utilisateurs disposant d'un equipement limite. Le procede preconise pour le marquage des sables par l'or 198 est une combinaison des methodes

  16. Comparison of analytical and numerical analysis of the reference region model for DCE-MRI. (United States)

    Lee, Joonsang; Cárdenas-Rodríguez, Julio; Pagel, Mark D; Platt, Simon; Kent, Marc; Zhao, Qun


    This study compared three methods for analyzing DCE-MRI data with a reference region (RR) model: a linear least-square fitting with numerical analysis (LLSQ-N), a nonlinear least-square fitting with numerical analysis (NLSQ-N), and an analytical analysis (NLSQ-A). The accuracy and precision of estimating the pharmacokinetic parameter ratios KR and VR, where KR is defined as a ratio between the two volume transfer constants, K(trans,TOI) and K(trans,RR), and VR is the ratio between the two extracellular extravascular volumes, ve,TOI and ve,RR, were assessed using simulations under various signal-to-noise ratios (SNRs) and temporal resolutions (4, 6, 30, and 60s). When no noise was added, the simulations showed that the mean percent error (MPE) for the estimated KR and VR using the LLSQ-N and NLSQ-N methods ranged from 1.2% to 31.6% with various temporal resolutions while the NLSQ-A method maintained a very high accuracy (<1.0×10(-4) %) regardless of the temporal resolution. The simulation also indicated that the LLSQ-N and NLSQ-N methods appear to underestimate the parameter ratios more than the NLSQ-A method. In addition, seven in vivo DCE-MRI datasets from spontaneously occurring canine brain tumors were analyzed with each method. Results for the in vivo study showed that KR (ranging from 0.63 to 3.11) and VR (ranging from 2.82 to 19.16) for the NLSQ-A method were both higher than results for the other two methods (KR ranging from 0.01 to 1.29 and VR ranging from 1.48 to 19.59). A temporal downsampling experiment showed that the averaged percent error for the NLSQ-A method (8.45%) was lower than the other two methods (22.97% for LLSQ-N and 65.02% for NLSQ-N) for KR, and the averaged percent error for the NLSQ-A method (6.33%) was lower than the other two methods (6.57% for LLSQ-N and 13.66% for NLSQ-N) for VR. Using simulations, we showed that the NLSQ-A method can estimate the ratios of pharmacokinetic parameters more accurately and precisely than the NLSQ-N and

  17. La nécropole de la basilique urbaine à Sirmium

    Directory of Open Access Journals (Sweden)

    Popović Ivana


    Full Text Available L’analyse des nécropoles située à l’intérieur et autour de la basilique urbaine, sur les sites 59, 46 et 47 de Sirmium, où 28 enterrements ont été enregistrés jusqu’à aujourd’hui, a démontré qu’il s’agissait de tombes de construction identique contenant un mobilier funéraires modeste mais homogène (peignes en os tripartites à deux rangées de dents, « petites » fibules ansées en arbalète en fer, « grandes » boucles ovales en fer, couteaux en fer et fragments de récipients en fin verre de couleur verte. En l’occurrence, dans la basilique même ont été découverts deux sarcophages miniatures et 13 tombes en briques. Ces petits sarcophages, ainsi que certaines tombes miniatures, contenaient des ossements d’individus adultes, ce qui incite à conclure que les dépouilles de défunts enterrés dans les nécropoles de Sirmium, situées hors de l’enceinte de la ville, ont été transportées à quelque moment dans la nécropole nouvellement formée intra muros. La création de cette nécropole est liée à l’érection de la basilique à l’intérieur de l’enceinte de la ville en 426. La nécropole était en fonction jusqu’à la destruction hunnique de la ville en 441. [Projekat Ministarstva nauke Republike Srbije, br. 177007: La romanisation, l’urbanisation et la transformation des centres urbains du charactère civil, militaire et résidentiel dansles provinces romaines sur la territoire de Serbie

  18. Characterization of Rock Wettability Though Dielectric Measurements Caractérisation de la mouillabilité des roches au moyen de mesures diélectriques

    Directory of Open Access Journals (Sweden)

    Bona N.


    Full Text Available The wettability of glass filters and Berea sandstone was investigated using the electric response in the interval 10² - 10 (to the power of 8 Hz. The natural wettability of the materials was modified to get two different sets of samples, one with strong water and the other with strong oil wettability. The samples were saturated to various degrees up to 40% with deionized water or brine. Measurements showed that the electric responses of water-wet and oil-wet samples were markedly different and more complex than those predicted by two standard models. The dispersivity and the loss tangent were found to be the most suitable parameters to check the wettability of the samples. La mouillabilité de filtres de verre et de grès de Béréa a été caractérisée par leur réponse électrique dans l'intervalle 10² - 10 puissance 8 Hz. Au moyen de traitements appropriés, la mouillabilité naturelle des matériaux a été modifiée afin d'obtenir deux séries différentes d'échantillons ayant respectivement de fortes mouillabilités à l'eau et à l'huile. Les échantillons ont été saturés à des degrés variés (pas plus de 40 % avec de l'eau permutée ou de la saumure. Les mesures ont montré que les réponses électriques des échantillons mouillables à l'eau ou mouillables à l'huile étaient nettement différentes et plus compliquées que celles prédites par deux modèles standard. En outre, on a pu constater que la dispersivité et la tangente de pertes constituent les paramètres les plus pertinents pour caractériser la mouillabilité des échantillons.

  19. Identification et prise en charge des femmes ayant des antécédents familiaux de cancer du sein (United States)

    Heisey, Ruth; Carroll, June C.


    Résumé Objectif Résumer les meilleures données portant sur les stratégies d’identification et de prise en charge des femmes qui présentent des antécédents familiaux de cancer du sein. Sources d’information Une recherche a été effectuée sur PubMed à l’aide des mots-clés anglais suivants : breast cancer, guidelines, risk, family history, management et magnetic resonance imaging screening, entre 2000 et 2016. La plupart des données sont de niveau II. Message principal Une bonne anamnèse familiale est essentielle lors de l’évaluation du risque de cancer du sein afin d’identifier les femmes qui sont candidates à une recommandation en counseling génétique pour un éventuel test génétique. On peut sauver des vies en offrant aux femmes porteuses d’une mutation au gène BRCA des interventions chirurgicales de réduction des risques (mastectomie bilatérale prophylactique, salpingo-ovariectomie bilatérale). Il faut encourager toutes les femmes qui présentent des antécédents familiaux de cancer du sein à demeurer actives et à limiter leur consommation d’alcool à moins de 1 verre par jour; certaines femmes sont admissibles à la chimioprévention. Il faut offrir aux femmes dont le risque à vie de cancer du sein est de 20 à 25 % ou plus un dépistage poussé par imagerie par résonance magnétique en plus d’une mammographie. Conclusion Une vie saine et la chimioprévention (chez les candidates) pourraient réduire l’incidence du cancer du sein; le dépistage poussé pourrait entraîner une détection plus précoce. Le fait d’aiguiller des femmes porteuses d’une mutation au BRCA vers la chirurgie de réduction des risques sauve des vies. PMID:27737991

  20. Axisymmetric Drainage in Hydrophobic Porous Media Micromodels Drainage en géométrie axisymétrique dans des milieux poreux hydrophobes à deux dimensions

    Directory of Open Access Journals (Sweden)

    Cuenca A.


    capillaires (Ca communément rencontrés lors des opérations d’extraction pétrolière. Nous utilisons deux types de micromodèles mouillables à l’huile : le premier est basé sur une méthode de déposition innovante permettant d’obtenir des monocouches de billes de verre de taille micronique, tandis que le second est microfabriqué dans du verre à partir de réseaux poreux aléatoires générés informatiquement. Chacun des modèles utilise un schéma d’injection central dans une géométrie radiale, ce qui engendre une variation continue du nombre capillaire pendant le drainage. Nous menons tout d’abord une analyse du drainage à l’échelle globale du micromodèle en couplant analyse d’image et mesures de pression et de débit. Les paramètres de base tels que perméabilité, porosité et saturation résiduelle en huile des modèles sont extraits dans cette première phase. Nous exploitons ensuite les possibilités de visualisation offertes par les micromodèles transparents pour mener une analyse locale du phénomène d’invasion. Les saturations locales et la largeur de front sont mesurées en fonction du nombre capillaire local. De façon intéressante, du fait de la géométrie radiale, nos expériences permettent de tracer continûment les courbes de désaturation capillaire sur plusieurs décades. Comme inféré, mais jamais observé précisément, les mesures de diverses expériences se regroupent sur une courbe maîtresse pour un micromodèle donné. Nous observons cependant des différences notables entre les deux types de micromodèle. Ces observations sont discutées à la lumière des différences géométriques existant entre les deux micromodèles à l’échelle du pore.

  1. Effects of Interfacial Reaction on the Radial Displacement of Oil by Alkaline Solutions Effets des réactions interfaciales sur le déplacement radial de l'huile par les solutions alcalines

    Directory of Open Access Journals (Sweden)

    Nasr-El-Din H. A.


    'eau, de géométrie radiale. Pour visualiser le processus de déplacement, on utilise un milieu poreux constitué de perles de verre fritté placées entre deux plaques de verre. Le milieu est initialement saturé avec la phase huileuse, à savoir l'huile de paraffine (non réactive, ou l'huile de paraffine enrichie de 1 % en poids d'acide linoléique (réactif. On étudie expérimentalement les effets du débit de l'injection et de la concentration en NaOH dans la phase aqueuse sur le schéma du déplacement. On mesure également la récupération en volume d'huile à l'épreuve de la filtration. Des mesures de tension interfaciale (IFT du système réactif ont été prises à l'aide d'un tensiomètre à goutte tournante. Une chute importante de la tension interfaciale traduit la réaction chimique à l'interface entre l'acide linéoléique de la phase huileuse et la soude NaOH de la phase aqueuse. On a également trouvé que l'évolution de la tension interfaciale IFT par rapport au temps dépendait de la concentration en NaOH, avec une activité interfaciale maximum (IFT minimum pour une concentration de 0,1 % de NaOH en poids. Les essais de déplacement font apparaître un changement significatif des schémas de déplacement au cours de la récupération secondaire du système réactif par rapport à ceux du système non réactif. Une chute significative de la récupération par filtration est obtenue pour les systèmes réactifs, particulièrement pour les débits d'injection élevés. On a trouvé que la récupération du système réactif variait suivant la concentration de NaOH dans la phase aqueuse, avec une récupération minimum pour 0,1 % de NaOH en poids.

  2. Crystal structures and thermal decomposition of permanganates AE[MnO{sub 4}]{sub 2} . n H{sub 2}O with the heavy alkaline earth elements (AE=Ca, Sr and Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Henning, Harald; Bauchert, Joerg M.; Conrad, Maurice; Schleid, Thomas [Stuttgart Univ. (Germany). Inst. fuer Anorganische Chemie


    next to amorphous phases. On the other hand, the already anhydrous Ba[MnO{sub 4}]{sub 2} thermally decomposes to hollandite-type BaMn{sub 8}O{sub 16} and BaMnO{sub 3} at 800 C.

  3. Understanding the residence of Co in ore minerals - towards the development of novel Co extraction strategies for laterite deposits (United States)

    Dybowska, Agnieszka; Norman, Rachel; Schofield, Paul; Herrington, Richard


    XRD. These low abundance minerals, identified in the samples using Raman spectroscopy, µXRD and EPMA, proved however to be very important Co-hosting phases. Electron microscopy and µ-XRF mapping revealed a strong Mn and Co association in all samples but little correlation between Co and Fe. The important determinant of Co concentration is thus its association with Mn oxides, a variety of which have been found in the samples studied. For example, in Shevchenko laterite asbolane was identified with Co concentrations varying from 0.25 to 12.4 wt% (6.3 wt% on average). Goethite was found to carry only minor Co i.e. below 0.03 wt% or 0.1-0.2 wt%. In samples from the Nkamouna laterite Mn oxide minerals were found to contain Co ranging widely from below 1 wt% in tectomanganate phases such as hollandite and pyrolusite, 5.5% wt% in lithiophorite and up to 21 wt% in lithiophorite-asbolane intermediates. No Co or minor Co (<0.1 wt%) was detected in Fe oxides and oxy-hydroxides. XANES spectroscopy shows that Co is bound in a range of Mn oxide minerals as Co3+. The structural environment of Co in these minerals is very similar with Co in octahedral coordination. Analysis of the EXAFS data for asbolane shows an apparent high degree of structural order around Co which suggest that Co is present as clustered aggregates. Our results indicate that Co should be efficiently and selectively removed from the studied laterites by targeted solubilisation of Mn oxides, which can be achieved via, for example, microbially mediated reductive mineral dissolution.

  4. Melting of carbonated pelites at 8-13 GPa: generating K-rich carbonatites for mantle metasomatism (United States)

    Grassi, Daniele; Schmidt, Max W.


    The melting behaviour of three carbonated pelites containing 0-1 wt% water was studied at 8 and 13 GPa, 900-1,850°C to define conditions of melting, melt compositions and melting reactions. At 8 GPa, the fluid-absent and dry carbonated pelite solidi locate at 950 and 1,075°C, respectively; >100°C lower than in carbonated basalts and 150-300°C lower than the mantle adiabat. From 8 to 13 GPa, the fluid-present and dry solidi temperatures then increase to 1,150 and 1,325°C for the 1.1 wt% H2O and the dry composition, respectively. The melting behaviour in the 1.1 wt% H2O composition changes from fluid-absent at 8 GPa to fluid-present at 13 GPa with the pressure breakdown of phengite and the absence of other hydrous minerals. Melting reactions are controlled by carbonates, and the potassium and hydrous phases present in the subsolidus. The first melts, which composition has been determined by reverse sandwich experiments, are potassium-rich Ca-Fe-Mg-carbonatites, with extreme K2O/Na2O wt ratios of up to 42 at 8 GPa. Na is compatible in clinopyroxene with D_{{Na}}^{{{{cpx}}/{{carbonatite}}}} = 10{-}18 at the solidus at 8 GPa. The melt K2O/Na2O slightly decreases with increasing temperature and degree of melting but strongly decreases from 8 to 13 GPa when K-hollandite extends its stability field to 200°C above the solidus. The compositional array of the sediment-derived carbonatites is congruent with alkali- and CO2-rich melt or fluid inclusions found in diamonds. The fluid-absent melting of carbonated pelites at 8 GPa contrasts that at ≤5 GPa where silicate melts form at lower temperatures than carbonatites. Comparison of our melting temperatures with typical subduction and mantle geotherms shows that melting of carbonated pelites to 400-km depth is only feasible for extremely hot subduction. Nevertheless, melting may occur when subduction slows down or stops and thermal relaxation sets in. Our experiments show that CO2-metasomatism originating from subducted

  5. Mineralogy of subducted clay and clay restite in the lower mantle (United States)

    Armstrong, L.; Skora, S. E.; Walter, M. J.


    Seismic tomography indicates that subducting oceanic lithosphere often penetrates the transition zone and eventually the lower mantle [e.g. 1, 2]. While mineralogical changes in the mafic and ultramafic portions of slabs have been well documented experimentally, the phase relations of overlying sediments at pressures above 25 GPa remain poorly studied. This is in part because sediments are expected to partially melt at sub-arc depth (P~2.5-4.5 GPa), and contribute to the genesis of arc magmas. Sediment restites left behind after the extraction of low pressure melts undergo major chemical changes, according to the melting reaction: Coe+Phen+Cpx+H2O = Grt+Ky+Melt [3]. However, sediments may not always melt depending on the thermal regime and volatile availability and composition [3]. Hence, chemically unmodified sediments as well as restites may be entrained to greater depths and contribute to compositional heterogeneity in the deep mantle. Indeed, mineral inclusions with compositions indicative of subducted sedimentary protoliths (CAS-phase; K-hollandite; stishovite) have been reported in 'ultradeep' diamonds and suggest that deep subduction and survival of sediments occurs to at least transition zone depths [4]. With this in mind, we have performed laser heated diamond anvil cell experiments at pressures of 8-80 GPa on two anhydrous glass starting materials: a marine clay and the restite that is left after 50% melt extraction of this clay at 3 GPa and 800 °C [3]. We chose to work with an anhydrous version of the marine clay given that the investigated pressure range exceeds that of phengite stability [5], and phengite is the only hydrous phase in subducted sediments at UHP conditions. The clay was heated along a P-T path representative of a cold subduction geotherm, whereas the clay restite was heated along a hotter subduction geotherm consistent with low pressure melting. Phases were identified by synchrotron X-ray micro-diffraction at beamline I15 of the Diamond

  6. La vocazione territoriale tra approccio sistemico e situazionista: analisi di una collaborazione culture driven tra aziende del made in Italy attraverso il caso del Contratto di Rete Polo Alta Moda Area Vestina / The territorial vocation between the “systemic” approach and the “situationist” approach: analysis of a culture-driven collaboration between Made-in-Italy firms. The case of the network contract of “Polo Alta Moda Area Vestina

    Directory of Open Access Journals (Sweden)

    Elena Cedrola


    Full Text Available Il presente lavoro si propone di mostrare come una collaborazione culture driven tra aziende del made in Italy possa innescare un processo virtuoso capace di alimentare la competitività d’impresa. Nello specifico, intende verificare la validità di una nuova chiave di lettura dei processi di governance del territorio, detta situazionista, che affianca la concezione prevalente in letteratura, definita unitaria o sistemica. Il punto di discrepanza principale tra le due visioni sembra essere quello della vocazione territoriale. Pur riconoscendo entrambe la presenza di interessi condivisi tra gli attori, la visione situazionista non riconosce alla vocazione la funzione “razionalizzante” riscontrabile nell’approccio sistemico. A seguito di una sintetica review della letteratura sui temi del territorio come cultura condivisa, sulla dimensione reticolare territoriale ed extraterritoriale e sul contratto di rete, verrà introdotto lo studio di un contratto di rete stipulato l’8 giugno 2010 tra le aziende che costituiscono il Polo Alta Moda Area Vestina. Attraverso le evidenze emerse da alcune interviste in profondità, sarà indagato il ruolo dell’azienda Brioni nella duplice veste di key player del territorio e di impresa capofila del contratto di rete analizzato e saranno esaminati gli altri attori che compongono il Polo Alta Moda. Le interviste realizzate hanno coinvolto i manager dell’impresa capofila del contratto di rete, il vice presidente Confindustria Pescara e presidente della Sezione Unificata Sistema Moda Chieti Pescara e il direttore delle fondazioni partecipanti al contratto.   This case study aims to validate how a culture-driven collaboration between firms could trigger the competitiveness of a Country, starting from a specific territorial culture. Specifically, it intends to investigate the validity of a new interpretation of the territorial governance processes, named “situationist”, that supports the prevailing

  7. Thermal and hydrodynamic study of a whirling liquid hydrogen layer under high heat flux; Etude thermique et hydrodynamique d'une couche tourbillonnaire d'hydrogenen liquide sous flux de chaleur eleve

    Energy Technology Data Exchange (ETDEWEB)

    Ewald, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires


    In order to achieve a cold neutrons source ({lambda} {>=} 4.10{sup -10} m) in a high flux reactor ({approx} 10{sup 15} neutrons/cm{sup 2}.s), a whirling liquid hydrogen layer (145 mm OD, effective thickness 15 mm, height about 180 mm) was formed, out-of-pile, in a cylindrical transparent glass vessel. The whirling motion was obtained by tangential injection of the liquid, near the wall. Thermal and hydrodynamical conditions of formation and laws of similarity of such a layer were studied. The characteristics of this whirling flow were observed as a function of mass flow rate (5 to 27 g/s; 4.3 to 23 l/mn), and of spillway width (18 and 25 mm). Six different nozzles were used : 1.0; 1.5; 1.9; 2.25; 2.65 and 3.0 mm ID. The total heat influx was found between 8.6 and 10.4 kW. The heat flux density was about 9.4 W/cm{sup 2} and the mean layer density around 80 per cent of that of the liquid hydrogen at 20.4 Kelvin. High speed movies were used to analyze the boiling regime. (author) [French] En vue de realiser une source de neutrons froids ({lambda} {>=} 4.10{sup -10} m) dans un reacteur a haut flux ({approx} 10{sup 15} neutrons thermiques/cm{sup 2}.s), on a forme dans un vase cylindrique transparent en verre, hors-pile, une couche tourbillonnaire ('vortex') d'hydrogene liquide (diametre exterieur 145 mm, epaisseur effective 15 mm, hauteur 180 mm environ). Le mouvement giratoire est obtenu par injection tangentielle du liquide pres de la paroi. L'etude porte sur la determination des conditions thermiques et hydrodynamiques de la formation d'une telle couche et sur les regles de similitude de ce phenomene. On a observe les caracteristiques de l'ecoulement giratoire en fonction du debit (de 5 a 27 g/s, soit de 4.3 a 23 1/mn), de la vitesse d'injection (entre 10 et 110 m/s) et de la largeur du deversoir (18 et 25 mm), ceci pour six diametres differents d'injecteur (1.0 ; 1.5; 1.9; 2.25; 2.65 et 3.0 mm). Le flux de chaleur total mesure

  8. Determinismo, analogia e preveggenza in Pierre Mabille. Basi per un raffronto con Juan Larrea

    Directory of Open Access Journals (Sweden)

    A. D’Urso


    col materialismo dialettico, in particolare mostrando quei passaggi del testo che sembrano rimandare ad alcune opere (anche minori di Marx ed Engels, piuttosto che indugiare sulla ricostruzione bio-bibliografica e approfondire l’influenza del monismo materialista, dell’ermetismo alchemico e della massoneria rivoluzionaria sulla costruzione “stilistica” stessa di questo breve saggio di Mabille.Intorno alle tematiche del determinismo, dell’analogia e della preveggenza verrà quindi messa in risalto l’originale rilettura di tesi fondamentali della dialettica hegeliana e del materialismo marxista, nella loro pos¬sibile sintesi coi principi del monismo cosmico. Interpretazione che consente di affrontare tali questioni dall’interno di un punto di vista pienamente surrealista, piuttosto che dall’esterno (e un po’ più metafisica¬mente come pretendeva Juan Larrea, così permettendo di gettare le basi per un possibile confronto tra quest’ultimo e l’amico Mabille, i quali non hanno mancato di influenzarsi a vicenda.Parole chiave: monismo; surrealismo; materialismo; Engels; marxismo.

  9. Les usages de la flexibilité temporelle chez les enseignantes du secondaire The uses of flexible time by female secondary-school teachers

    Directory of Open Access Journals (Sweden)

    Julie Jarty


    Full Text Available De par sa flexibilité temporelle, il existe une perception largement répandue selon laquelle la profession enseignante serait woman-friendly, « bien pour une femme ». Le « plafond de verre » est pourtant une réalité pour de nombreuses femmes au sein de l’enseignement du second degré. Centré sur une étude des perceptions et des pratiques temporelles au sein de ce groupe professionnel dans une perspective de genre, cet article s’appuie sur une analyse critique des discours de 40 entretiens individuels réalisés auprès d’hommes et de femmes enseignant-e-s du secondaire et de leurs « carnets-temps ». Il s’agit d’explorer la manière dont ils et elles utilisent leur temps et cette flexibilité professionnelle. Le résultat de cette recherche permet de montrer que les expériences temporelles sexuées sont particulièrement prédominantes, ce qui contribue à expliquer les difficultés des femmes enseignantes à accéder aux positions les plus prestigieuses et les mieux rémunérées de la hiérarchie. Néanmoins, la mobilisation d’une typologie des expériences temporelles des enseignantes nous conduit à identifier l’existence de discours alternatifs, reconnaissant ainsi les contrastes du degré selon lequel les rapports sociaux de sexe sont reproduits, reconfigurés ou transformés au sein de la profession.Because of its temporal flexibility, there is a widespread notion that the teaching profession is ‘woman-friendly’ or “good for women”. However, there is extensive evidence that a ‘glass ceiling’ exists for female secondary school teachers too. Based on a study of temporal perceptions and practices within the teaching profession in a gendered perspective, this paper draws on the critical discourse analysis of forty individual interviews conducted with male and female secondary school teachers and of their schedules. The aim was to examine the use they make of their time and professional flexibility

  10. Proposta di uno studio multicentrico per la valutazione del fenomeno delle infezioni correlate a pratiche assistenziali in residenze socioassistenziali in Italia

    Directory of Open Access Journals (Sweden)

    S. Brusaferro


    Full Text Available

    Razionale dello studio proposto In contesti come le Residenze Sanitarie Assistenziali (RSA, le Residenze Protette (RP, l’Assistenza Domiciliare Integrata (ADI la letteratura e le prime esperirne italiane evidenziano come il problema ICPA sia importante e, pur variando le tipologie di infezione prevalenti, i costi individuali, sociali ed economici ad esse collegati rimangono molto elevati.

    In questo scenario diventa importante che i Comitati per il Controllo delle Infezioni Ospedaliere (CIO aziendali affrontino il problema del controllo delle infezioni in ambito extraospedaliero e comincino a strutturare modelli organizzativi in grado di operare efficacemente. Il dimensionamento del problema, ovvero l’attività di sorveglianza epidemiologica, anche in questo caso è tra le prime attività necessarie di provata efficacia.

    Obiettivo dello studio: una prima valutazione della dimensione del problema ICPA nelle strutture RSA presenti nelle diverse regioni italiane attraverso uno studio di prevalenza nazionale. Materiali e metodi: l progetto prevede una prima fase con l’individuazione dei centri partecipanti e dei rispettivi referenti medici ed infermieristici. Successivamente si procederà, utilizzando la metodologia già testata in uno studio pilota, alla formazione del personale sull’uso degli strumenti. Saranno arruolati tutti i pazienti degenti da oltre 48 ore nelle RSA partecipanti, escludendo quelli in dimissione o in trasferimento nel giorno di rilevazione. I rilevatori, esterni alla struttura, raccoglieranno i dati consultando il quaderno infermieristico, il quaderno terapia, il diario clinico, la cartella clinica ed esaminando ciascun paziente per validare la eventuale presenza di “devices” e confermare sintomi e segni rientranti nelle definizioni di caso. Laddove necessario verrà consultato il personale medico ed infermieristico della struttura. Le variabili raccolte saranno centrate su dati

  11. L’exposition contrôlée à la lumière et à l’obscurité ajuste le rythme du cortisol salivaire chez les travailleurs de nuit

    Directory of Open Access Journals (Sweden)

    Anny Casademont


    Full Text Available Dans cette étude réalisée sur le terrain et en laboratoire, nous avons testé l’efficacité d’une intervention consistant à contrôler l’exposition à la lumière/obscurité de façon à favoriser l’adaptation circadienne au travail de nuit. Six travailleurs permanents de nuit (moyenne d’âge 37,1 ± σ : 8,1 ans avaient comme consigne de s’exposer de façon intermittente à une lumière blanche vive plein spectre (~2 000 lux au cours des 6 premières heures de leur quart de travail de 8 heures. Il leur était demandé de se protéger de la lumière solaire du matin avec des verres teintés (densité gris neutre, transmission visuelle de la lumière 15 % et de maintenir des épisodes réguliers de sommeil/obscurité dans une pièce très sombre. Ces épisodes devaient commencer 2 heures après la fin de chaque quart de travail de nuit. Cinq travailleurs du groupe contrôle (41,1 ± σ : 9,9 ans ont été étudiés alors qu’ils devaient uniquement maintenir un horaire régulier de sommeil/obscurité. Des procédures de routine constante, réalisées avant et après une série d’environ 12 quarts de travail de nuit s’échelonnant sur 3 semaines, ont montré chez les travailleurs du groupe traitement une variation significative dans l’heure d’apparition du pic de cortisol ainsi qu’un ajustement de ce rythme à un horaire de travail de nuit. Un plus petit changement de phase a été observé dans le groupe contrôle, ce qui suggère une adaptation partielle à l’horaire de travail de nuit. Nos résultats démontrent l’efficacité d’une exposition judicieuse à la lumière et à l’obscurité pour favoriser l’adaptation des rythmes physiologiques au travail de nuit.The efficacy of a light/darkness intervention designed to promote circadian adaptation to night shift work was tested in this combined field and laboratory study. Six permanent night shift workers (mean age: 37.1 / s: 8.1 years were instructed to

  12. Tel-Aviv a cent ans ! 1909-2009 : un siècle de globalisation au Proche-Orient

    Directory of Open Access Journals (Sweden)

    Caroline Rozenholc


    Full Text Available En mettant en perspective les grandes étapes du développement de Tel-Aviv, cet article propose de lire la capitale économique et culturelle d’Israël comme un lieu d’ancrage des idéologies du 20ème siècle européen au Proche-Orient. Sans faire l’impasse sur la mondialisation à l’œuvre dans la ville aujourd’hui, cette réflexion se déploie autour de la l’inscription récente de Tel-Aviv au patrimoine mondial de l’humanité. D’un quartier de Jaffa, Tel-Aviv est devenue la « Ville Blanche », la ville du Bauhaus, la vitrine des tendances du mouvement moderne en architecture. L’enchaînement raisonné de ces différents moments permet de mettre à jour la manière dont cette ville « sans histoire » est entrée de plain-pied dans l’Histoire. Ainsi, des maisons d’un étage qui marquent la naissance de la ville, à la tour de verre et d’aluminium de « l’architecte du blanc », Richard Meir, en passant par la reconnaissance de la ville comme inflexion « locale » d’une proposition architecturale internationale, Tel-Aviv se révèle comme un laboratoire exceptionnel de l’articulation local/global. Et l’engouement des architectes les plus prestigieux pour la ville ne fait que réactualiser Tel-Aviv comme lieu où jouent ces assemblages complexes d’espaces et de temporalités.Putting Tel Aviv’s development into perspective, this contribution suggests “reading” Israel’s economical and cultural capital – Tel-Aviv – as the successful implementation of 20th century European ideologies in the Middle East, Jaffa, Palestine. The starting point of this paper is the proclamation of Tel-Aviv as a World Cultural Heritage site for its unique urban and historical fabric, commonly known as the “White City” or the Bauhaus City. But how this city – generally considered as “devoid of history” – too set foot in History? And how from the one storey houses of the first neighborhood of Tel

  13. A survey of the current practice of the informed consent process in general surgery in the Netherlands. (United States)

    Leclercq, Wouter Kg; Keulers, Bram J; Houterman, Saskia; Veerman, Margot; Legemaate, Johan; Scheltinga, Marc R


    . METHODE: Alle chirurgen en andere leden van de Nederlandse Vereniging voor Heelkunde ontvingen een online multiple-choice vragenlijst betreffende de belangrijkste aspecten van SIC. RESULTATEN: In totaal waren er 453 bruikbare reacties uit meer dan 95% van alle Nederlandse ziekenhuizen (respons 30%). De kennis over SIC blijkt zeer beperkt. Slechts 55% van de chirurgen bleek bekend met de drie basiselementen van SIC ('beoordelen van de competentie van een patiënt', 'verstrekken van informatie' and 'adequaat vastleggen van de toestemming van de patiënt'). De dagelijkse praktijk liet behoorlijke verschillen tussen alle respondenten zien, maar chirurgen in opleiding scoorden significant slechter vergeleken met chirurgen. 17% van alle chirurgen kreeg de afgelopen vijf jaar te maken met een klacht betreffende SIC, wat zou kunnen wijzen op een suboptimale implementatie van SIC in de dagelijkse praktijk. De kwaliteit van het preoperatieve informed consent proces is in Nederland verre van goed. Chirurgen in opleiding scoorden minder goed dan chirurgen en dienen beter geschoold te worden. Het hele SIC proces zou geformaliseerd moeten worden in protocollen. Moderne hulpmiddelen zoals interactieve softwareprogramma's kunnen hierbij mogelijk helpen. Door het verbeteren van het SIC proces kan de patiëntentevredenheid verhoogd worden terwijl het aantal klachten mogelijk wordt verminderd.

  14. Composites organiques-inorganiques pour la substitution et la réparation osseuse : concepts, premiers résultats et potentialités Organic-inorganic composites for bone substitute and bone repair applications: concepts, first results and potentialities

    Directory of Open Access Journals (Sweden)

    Peroglio Marianna


    Full Text Available Ce document présente un très bref aperçu de l'intérêt des matériaux composites organique – inorganique pour la substitution et la réparation osseuse. Deux types de composites sont présentés. Dans une première partie, des matériaux poreux en céramique ou bio-verre élaborés par la technologie des poudres sont imprégnés par un polymère. Cette imprégnation se traduit par une forte augmentation de l'énergie à la rupture du squelette céramique, permettant de limiter le risque de rupture fragile. L'augmentation des propriétés mécaniques des substituts osseux céramiques par une phase polymère peut être mise en regard des mécanismes de renforcement présents dans l'os et du rôle du collagène sur la ténacité de celui-ci. Dans une deuxième partie, des composites denses sont élaborés par des technologies de plasturgie, qui permettent de réaliser des produits de formes complexes. Les phases polymères et céramiques sont ici choisies pour leurs caractères respectifs résorbable et ostéo-inducteur. Ces composites permettent la création rapide d'hydroxyapatite à leur surface et accélèrent la guérison osseuse. A terme, ils sont résorbés. Ces deux exemples démontrent les potentialités de tels multi-matériaux architecturés pour la réalisation de substituts osseux plus résistants mécaniquement et apportant de nouvelles fonctionnalités, ainsi que pour la production de produits d'ostéosynthèse favorisant les processus de guérison osseuse. Here we show a brief outline of organic-inorganic composites for bone substitute and bone repair applications. Two types of composites are presented. In a first strategy, porous ceramics and bioactive glasses processed by sintering methods are impregnated by a polymer. The strong improvement of the mechanical properties of the ceramic scaffolds by a polymer phase can be linked to the one present in bone with the role of collagen on bone toughness. In a second strategy, a

  15. L’aggressività della coppia criminale: la strage di Erba analizzata nell’ottica della coscienza intersoggettiva di D. Stern/L'agressivité des couples criminels : le massacre de Erba analysé par l'approche de la conscience intersubjective de Daniel Stern/The agressiveness of the criminal couples: the analysed massacre of Erba using the approach of the intersubjective conscience of Daniel Stern

    Directory of Open Access Journals (Sweden)

    Pasquale Caponnetto


    Full Text Available La coppia criminale è un fenomeno poco comune nell'ambito dei delitti in quanto la maggior parte dei criminali commette il crimine da solo o coinvolge altri individui solo per caso. Ciò nonostante, la letteratura rivela una serie di coppie criminali che hanno commesso diversi crimini, fino ad arrivare all’omicidio. Alcuni hanno ucciso per denaro, altri per odio, altri ancora per amore, per vendetta, per perversione. Bonnie e Clyde, Olindo e Rosa, Erika e Omar sono espressione di un viaggio nel fenomeno del “crimine di coppia” in cui manifestazioni di follia a due, al di là dell’infatuazione reciproca e della dipendenza psicologica, si svuotano di qualsiasi accezione romantica per concretizzarsi in qualcosa di spaventoso e incontenibile, capace di sfuggire ad ogni tipo di catalogazione e comprensione. Nel presente lavoro, in particolare, si andrà ad analizzare la coppia criminale degli autori della strage di Erba, che verrà esaminata nell’ottica della coscienza intersoggettiva di Stern. Le couple criminel est un phénomène rare puisque la majorité des crimes sont commis par des criminels seuls ou ce n’est que par hasard qu’ils impliquent d’autres personnes. Toutefois, la littérature parle d’une série de couples criminels qui ont commis des différents types de crimes (homicide inclus. Certains d’entre eux tuent pour de l’argent, certains autres à cause de la haine, de l’amour, de la revanche ou de la perversion. Bonnie et Clyde, Olindo et Rosa, Erika et Omar constituent des exemples du phénomène du « crime en couple ». Ce sont des situations de folie à deux qui n’ont aucune acception romantique et qui se traduisent en quelque chose d’horrifiant et d’incontrôlé. Dans cet article, les auteurs vont analyser le couple criminel composé par les responsables du massacre de Erba (Italie du Nord. L’objectif est d’examiner ce couple en utilisant l’approche de la conscience intersubjective de Daniel

  16. MONA, LISA and VINCI Soon Ready to Travel to Paranal (United States)


    Spatiale (DESPA) of the Paris Observatory. It was used in 1991 at the Kitt Peak National Observatory (Arizona, USA), for the first (coherent) combination of the light beams from two independent telescopes by means of optical fibers of fluoride glass. It has since been in operation for five years as a focal instrument at the IOTA Interferometer (Mount Hopkins, Arizona, USA) within a collaboration with the Harvard Smithsonian Center for Astrophysics), producing a rich harvest of scientific data. The VINCI partners The VINCI instrument is constructed in a collaboration between ESO (that also finances it) and the following laboratories and institutes: * DESPA (Paris Observatory) provides the expertise, the general concept, the development and integration of the optomechanics (with the exception of the camera) and the electronics, * Observatoire Midi-Pyrénées that produces the control software * The LISA infrared camera is developed by the Max-Planck-Institut für Extraterrestrische Physik (Garching, Germany), and * ESO provides the IR camera electronics and the overall observational software and is also responsible for the final integration. DESPA delivered VINCI to ESO in Garching on September 27, 2000, and is now assembling the instrument in the ESO optical workshop. It will stay here during three months, until it has been fully integrated and thoroughly tested. It will then be shipped to Paranal at the beginning of next year. After set-up and further tests, the first observations on the sky are expected in late March 2001. Fluoride fibers guide the light The heart of VINCI - named MONA - is a fiber optics beam combine unit. It is the outcome of a fertile, 10-year research partnership between Science (DESPA) and Industry ("Le Verre Fluoré" [2]). Optical fibers will be used to combine the light from two telescopes inside VINCI . Since the instrument will be working in the near-infrared region of the spectrum (wavelength 2-2.5 µm), it is necessary to use optical fibers

  17. Nucléation, ascension et éclatement d'une bulle de champagne (United States)

    Liger-Belair, G.


    People have long been fascinated by bubbles and foams dynamics, and since the pioneering work of Leonardo da Vinci in the early 16th century, this subject has generated a huge bibliography. However, only quite recently, much interest was devoted to bubbles in Champagne wines and carbonated beverages. Since the time of the benedictine monk dom Pierre Perignon (1638-1715), champagne is the wine of celebration. This fame is largely linked to the elegance of its effervescence and foaming properties. In this book, the latest results about the chemical physics behind the bubbling properties of Champagne and sparkling wines are collected and fully illustrated. The first chapter is devoted to the history of champagne and to a presentation of the tools of the physical chemistry of interfaces needed for a whole comprehension of the book. Then, the three main steps of a fleeting champagne bubble's life are presented in chronological order, that is, the bubble nucleation on the glass wall (Chap.2), the bubble ascent and growth through the liquid matrix (Chap.3), and the bursting of bubbles at the liquid surface (Chap.4), which constitutes the most intriguing, functional, and visually appealing step. L'objectif général de ce travail consacré à l'étude des processus physicochimiques liés à l'effervescence des vins de Champagne était de décortiquer les différentes étapes de la vie d'une bulle de champagne en conditions réelles de consommation, dans une flûte. Nous résumons ci-après les principaux résultats obtenus pour chacune des étapes de la vie de la bulle, depuis sa naissance sur les parois d'une flûte, jusqu'à son éclatement en surface. Nucléation À l'aide d'une caméra rapide munie d'un objectif de microscope, nous avons pu mettre à mal une idée largement répandue. Ce ne sont pas les anfractuosités de la surface du verre ou de la flûte qui sont responsable de la nucléation hétérogène des bulles, mais des particules adsorbées sur les parois du

  18. Calibrazioni a terra e prestazioni in volo di spettrometri ad immagine nel visibile e nel vicino infrarosso per l'esplorazione planetaria (United States)

    Filacchione, Gianrico


    progettuale e realizzativa dei parametri e de lle prestazioni strumentali; in generale infatti non solo sarà necessario mantenere le dimensioni, il peso, i consumi elettrici ed il data-volume entro i requisiti disponibili del satellite ma anche ottimizzare i disegni ottici, meccanici ed elettronici al fine di ottenere le massime prestazioni possibili in funzione della natura del target osservato e dei parametri orbitali della missione. Questa tesi descrive i metodi utilizzati per caratterizzare il funzionamento di spettrometri ad immagine per l’esplorazione planetaria. L’attività svolta ha riguardato sia la misura in laboratorio dei parametri strumentali fondamentali sia l’analisi dei dati in volo su cui verificarne ed eventualmente correggerne la risposta. Il funzionamento degli strumenti e la metodologia di calibrazione vengono descritti nelle due parti principali e nelle appendici di questa tesi per gli esperimenti Cassini-VIMS-V e Rosetta-VIRTIS-M. La prima parte è dedicata all’esperimento VIMS-V sul satellite Cassini, il cui disegno ottico, originariamente proposto da Francis Reininger, verrà successivamente riutilizzato e perfezionato su VIRTIS-M (Reininger et al., 1994; Miller et al., 1996). Il capitolo 1 contiene una descrizione dei parametri ottici, strutturali, termici ed elettronici di VIMS-V mettendone in risalto gli aspetti più innovativi del progetto. Vengono inoltre descritti la collocazione dell’esperimento sul satellite Cassini, il coallineamento con gli altri strumenti di remote sensing, i possibili modi operativi ed il formato dei dati scientifici. Il capitolo 2 riguarda il processo di calibrazione ed analisi dei dati in volo di VIMS-V. La procedura eseguita per calibrare radiometricamente lo strumento utilizzando i dati della superficie della Luna e per stimare il flat-field mediante i dati dell’atmosfera di Venere viene dettagliatamente descritta assieme agli algoritmi utilizzati per la rimozione di diversi effetti strumentali (read

  19. Conception et calibration d'un sonoreacteur pour l'oxydation de la cellulose par le systeme TEMPO/NaOCl/NaBr (United States)

    Paquin, Michel

    grande consommation d'energie et de reactif qui rend le procede difficilement accessible au milieu industriel. L'utilisation des ultrasons lors de la reaction d'oxydation permet de reduire de 50% le temps de reaction et d'autant la consommation de produits chimiques. Actuellement le processus d'oxydation s'effectue en mode discontinu pour une quantite de 20 grammes de pate dans un reacteur en verre dans un bain a ultrason. L'objectif principal de ce travail est d'elaborer un sonoreacteur en mode semi-continu afin d'etre en mesure de transferer une reaction d'oxydation du mode discontinu en mode semi-continu. Le transfert de reaction sera effectue en realisant la calibration de l'activite acoustique des deux differents reacteurs, discontinu et semi-continu, par la methode de Weissler. La methode de Weissler quantifie le taux de production radicalaire en mesurant la formation d'iode moleculaire d'une solution aqueuse d'iodure de potassium sous ultrason. Suite a sa calibration, le sonoreacteur pilote (mode semi-continu) a demontre une augmentation de la production radicalaire de 683 % a 170 kHz en comparaison avec l'utilisation d'un bain a ultrason a la meme frequence. Lors de la reaction d'oxydation, la puissance optimale utilisee dans le bain a ultrason a 170 kHz est de 1000 W. La puissance utilisee selon les resultats de calibration obtenue dans le sonoreacteur pilote est de 125 W soit une diminution de l'energie appliquee de 87,5 %. Lors de la reaction d'oxydation, le taux de production des groupements carboxylates est de 2,6 mmol COOH kg/min dans le bain a ultrason et de 6,87 mmol COOH kg/min dans le sonoreacteur pilote soit une augmentation de 164% du taux de formation. Selon les resultats obtenus, l'utilisation d'un sonoreacteur en mode continu peut etre envisageable pour la reaction d'oxydation de la cellulose par le systeme TEMPO-NaOCl-NaBr en industrie au niveau industriel.

  20. Il quadraturismo in Pallazzo Pitti da Cosimo II a Cosimo III de' Medici The quadraturism on the Pallazzo Pitti from Cosimo II to Cosimo III of Medici

    Directory of Open Access Journals (Sweden)

    Fauzia Farneti


    Full Text Available Nei primi decenni del Seicento la pittura decorativa a Firenze risulta ancora legata all'ornamentazione tradizionale tardomanierista attuata nei modi di Alessandro Allori o di Bernardino Barbatelli detto il Poccetti. L'interesse per le novità e per l'aggiornamento dell'ambiente artistico fiorentino portarono il granduca Ferdinando II a chiamare a Firenze tra il 1636 ed il 1637 Pietro da Cortona, Angelo Michele Colonna e Agostino Mitelli. I due bolognesi completarono il ciclo pittorico celebrativo del governo di Ferdinando cui aveva dato inizio Giovanni da San Giovanni, con la decorazione delle tre sale di rappresentanza del quartiere estivo di palazzo Pitti realizzata tra il 1637 ed il 1641. L'intervento, condotto secondo il più moderno linguaggio barocco che vede la perfetta integrazione dell'illusionismo architettonico, che supera i limiti dello spazio reale, con le scene figurative, verrà a costituire nell'ambiente fiorentino un ineludibile modello di riferimento nella decorazione d'interni, soluzioni di grande modernità su cui si formerà Jacopo Chiavistelli e i giovani della sua scuola. Anche Giovan Carlo, fratello del granduca, nel 1637 diede inizio ad una serie di trasformazioni che si protrassero per oltre un ventennio, trasformando gli ambienti a lui assegnati in Pitti in veri e propri luoghi di delizie, decorati dagli artisti più significativi del momento quali ad esempio Angelo Michele Colonna, Agostino Mitelli, Pietro da Cortona, Jacopo Chiavistelli. Fu quest'ultimo frescante che con i suoi 'scolari', fin dagli anni Cinquanta fu attivo in palazzo Pitti, decorando a quadratura gli ambienti dei quartieri dei membri della famiglia granducale, ambienti che in gran parte sono andati perduti in quanto interessati dalle ristrutturazioni lorenesi e sabaude. Con i lavori commissionati dal gran principe Ferdinando si chiude in palazzo Pitti la grande stagione del quadraturismo barocco fiorentino.Nos primeiros decênios do Seiscentos a

  1. Caracterisation experimentale de la transmission acoustique de structures aeronautiques (United States)

    Pointel, Vincent

    Le confort des passagers à l'intérieur des avions pendant le vol est un axe en voie d'amélioration constante. L'augmentation de la proportion des matériaux composites dans la fabrication des structures aéronautiques amène de nouvelles problématiques à résoudre. Le faible amortissement de ces structures, en contre partie de leur poids/raideur faible, est non favorable sur le plan acoustique, ce qui oblige les concepteurs à devoir trouver des moyens d'amélioration. De plus, les mécanismes de transmission du son au travers d'un système double paroi de type aéronautique ne sont pas complètement compris, c'est la raison qui motive cette étude. L'objectif principal de ce projet est de constituer une base de données pour le partenaire industriel de ce projet : Bombardier Aéronautique. En effet, les données expérimentales de performance d'isolation acoustique, de systèmes complets représentatifs d'un fuselage d'avion sont très rares dans la littérature scientifique. C'est pourquoi une méthodologie expérimentale est utilisée dans ce projet. Deux conceptions différentes de fuselage sont comparées. La première possède une peau (partie extérieure du fuselage) métallique raidie, alors que la deuxième est constituée d'un panneau sandwich composite. Dans les deux cas, un panneau de finition de fabrication sandwich est utilisé. Un traitement acoustique en laine de verre est placé à l'intérieur de chacun des fuselages. Des isolateurs vibratoires sont utilisés pour connecter les deux panneaux du fuselage. La simulation en laboratoire de la couche limite turbulente, qui est la source d'excitation prépondérante pendant la phase de vol, n'est pas encore possible hormis en soufflerie. C'est pourquoi deux cas d'excitation sont considérés pour essayer d'approcher cette sollicitation : une excitation mécanique (pot vibrant) et une acoustique (champ diffus). La validation et l'analyse des résultats sont effectuées par le biais des logiciels

  2. Visual Investigation of Retrograde Phenomena and Gas Condensate Flow in Porous Media Étude visuelle des phénomènes rétrogrades et de l'écoulement des gaz de condensat en milieux poreux

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    Danesh A.


    Full Text Available The mechanism of retrograde condensation and the flow of gas-condensate in horizontal porous media under simulated reservoir conditions were visually studied. Two-dimensional glass micromodels with homogeneous pore structures, as well as heterogeneous patterns, reproduced from real rock micrographs were employed in this study. Depletion tests were carried out using synthetic multicomponent hydrocarbon gas mixtures and also a North Sea gas condensate. The multiphase flow behaviour of the tested systems, as observed and recorded on video, is presented here along with the measured data. In water-wet pores, condensate was observed to be formed as a continuous thin film on connate water, which was the preferred site for condensation. Pressure reduction below the system cricondenbar resulted in the growth of the condensate almost exclusively on water rings at pore throats and dead end pores. The condensate was observed to flow through thin films even at low saturations, with little contribution to the condensate recovery. The rate of pressure depletion influenced the gas flow shear and was found to strongly affect the condensate propagation. Local instabilities could promote significant condensate movement in pore sections which would only be retarded further downstream by capillary effects diminishing the condensate recovery. Relative permeability-saturation relation-ships for gas-condensate flow should not be expected to take the same form as the oil-gas relative permeability for solution gas or external gas drive. Le mécanisme de la condensation rétrograde et l'écoulement des gaz de condensat en milieu poreux horizontal dans une simulation des conditions naturelles ont fait l'objet d'études visuelles. Des micromodèles en verre bi-dimensionnels à structure poreuse homogène, et des éléments hétérogènes reproduisant des micrographies de roches réelles, ont été utilisés pour cette étude. Des essais d'épuisement ont été effectu

  3. Restrizioni strutturali e teoria linguistica nel discorso bilingue

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    Antonio Piga


    grammatical’ and which on the other hand are those considered as ‘non-grammatical’ or ‘impossible’, (c the possible existence of grammatical constraints and models that may govern the compatibility of constituents of the two codes in contact. Riassunto - L’obiettivo del presente contributo è quello di offrire un panorama rappresentativo di un fenomeno largamente diffuso in Sardegna: l’alternanza linguistica da parte degli immigranti durante le varie interazioni con i parlanti sardi. La commutazione di codice rappresenta infatti una di quelle strategie discorsive cui ricorrono gli apprendenti durante le varie fasi di acquisizione di una L2, allo scopo di soddisfare eventuali esigenze comunicative e compensare le carenze nella competenza linguistica durante i vari scambi interazionali con gli interlocutori nativi nel paese in cui temporaneamente soggiornano. In questa indagine verrà esaminata non tanto la commutazione di codice italiano/inglese, italiano/spagnolo, ecc. quanto piuttosto l’inclusione della varietà dialettale sarda fra le lingue che gli immigrati adoperano nelle diverse interazioni sociali con i parlanti nativi allo scopo di “accelerare l’assimilazione nel gruppo dominante” (Loi Corvetto 2000: 42.Il corpus consiste di circa trenta ore di registrazione di parlato spontaneo. Si è ritenuta infatti prioritaria la possibilità di osservare e esaminare la produzione linguistica di parlanti che interagissero in contesti situazionali i più naturali possibili, pertanto le tecniche adoperate nella raccolta del corpus rispondono principalmente all’ esigenza di poter ottenere dati relativi al parlato naturale, non sorvegliato, di cui è possibile disporre solamente se i parlanti non sanno di essere registrati.Da un punto di vista metodologico, si tratterà in primo luogo di individuare: (a le caratteristiche morfologiche e sintattiche del discorso bilingue italiano/campidanese da parte degli apprendenti italiano L2, vale a dire quali categorie

  4. Composite Risers for Deepwater Applications Risers composites pour applications en mer profonde

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    Metivaud G.


    Full Text Available This paper is devoted to the high performance composite tubes developed by the Institut Français du Pétrole (IFP and Aerospatiale for deepwater risers applications. The design principles of the tubes are first presented, along with results of preliminary work carried out as part of the initial feasibility study. Applications of composite tubes to drilling riser Kill and Choke lines and to TLP production risers, both of which have been studied in detail, are then described. Technical and operational advantages obtained from such applications are discussed. Cet article présente les travaux réalisés par l'Institut Français du Pétrole et l'Aerospatiale dans le domaine des tubes composites haute performance pour les applications aux liaisons fond-surface de forage et de production en mer profonde. Les matériaux composites avancés sont une classe de matériaux très particulière, présentant à la fois des caractéristiques mécaniques élevées et une densité spécifique faible. Ils sont utilisés principalement par les industries de l'aéronautique et de l'espace, mais l'industrie pétrolière en mer profonde est un secteur où ils peuvent trouver dans l'avenir des applications très intéressantes, notamment les tubes de risers. Les tubes de risers pétroliers en mer présentent en effet une gamme de spécifications élevées (diamètres, pression, traction, fatigue dans un environnement sévère et leur poids suspendu peut pénaliser fortement les systèmes de forage ou de production par grande profondeur d'eau. Un premier concept de tube composite haute performance a été développé par IFP et Aerospatiale au début des années 1980 ; sa partie courante, réalisée par enroulement filamentaire de fibres de verre R ou de fibres de carbone, et son système d'embout ont été soumis à une série d'essais mécaniques (pression interne jusqu'à 105 MPa, traction supérieure à 1 000 kN pour un diamètre nominal de 0,1 m, millions de

  5. Determining concentration fields of tracer plumes for layered porous media in flow-tank experiments (United States)

    Yu, Zhongbo; Schwartz, Franklin W.

    In the laboratory, computer-assisted image analysis provides an accurate and efficient way to monitor tracer experiments. This paper describes the determination of detailed temporal concentration distributions of tracers in a flow-tank experiment by analyzing photographs of plumes of Rhodamine dye through the glass wall of the tank. The methodology developed for this purpose consists of four steps: (1) digitally scanning black and white negatives obtained from photographs of the flow-tank experiment; (2) calibrating and normalizing each digitized image to a standard optical-density scale by determining the relation between the optical density and pixel value for each image; (3) constructing standard curves relating the concentration in an optical density from five experimental runs with predetermined concentrations (2-97mg/L) and (4) converting the optical density to concentration. The spatial distribution of concentration for two photographs was determined by applying these calibration and conversion procedures to all pixels of the digitized images. This approach provides an efficient way to study patterns of plume evolution and transport mechanisms. Résumé Au laboratoire, l'analyse d'images assistée par ordinateur est un moyen précis et efficace pour suivre certaines expériences de traçage. Ce papier présente comment sont déterminées dans le détail les distributions temporelles de la concentration en traceur au cours d'une expérience d'écoulement en réservoir au moyen de l'analyse de photographies de panaches de rhodamine à travers la paroi de verre du réservoir. La méthodologie développée dans cette expérience suit quatre étapes: (1) digitalisation par balayage des négatifs noir et blanc des prises de vue de l'expérience d'écoulement en réservoir (2) calibration et normalisation de chaque image digitalisée par rapport à une échelle étalon de densité optique en déterminant la relation entre la densité optique et la valeur des pixels

  6. De strijd tegen sociale ongelijkheid en uitsluiting op de arbeidsmarkt

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    Pieter Decelle


    jobseekers. The social workers surveyed in this study are, however, well aware of the structural inequalities that exist in the labour market. Each respondent was able to describe some of these structural barriers, which impact on the employment opportunities of their clients. However, action to address these barriers is absent. SAMENVATTINGDe strijd tegen sociale ongelijkheid en uitsluiting op de arbeidsmarkt Sociale ongelijkheid en sociale exclusie zijn maatschappelijke problemen waarmee we in onze samenleving meer dan ooit worden geconfronteerd. Dit uit zich onder andere in hoge werkloosheidscijfers bij personen met een verre afstand tot de arbeidsmarkt. In Vlaanderen zet de sociale economie, een verzamelnaam voor organisaties die in hun doelstellingen de realisatie van bepaalde maatschappelijke meerwaarden vooropstellen, zich sinds de jaren 70 van de twintigste eeuw in om de werkloosheidsgraad bij personen uit de kansengroepen terug te dringen. Dit gebeurt via het aanbieden van opleidings- en tewerkstellingskansen. De Vlaamse Dienst voor Arbeidsbemiddeling en Beroepsopleiding (VDAB onderscheidt vier kansengroepen – personen van allochtone origine, kortgeschoolden, personen met een arbeidshandicap en ouderen (50-plussers – die omwille van het behoren tot één van deze groepen minder kansen op werk ondervinden. In mijn onderzoek breng ik in kaart hoe deze sector werkzoekenden tracht te activeren op de arbeidsmarkt. Meer specifiek onderzoek ik in welke mate een structurele visie op sociaal werk tot uiting komt in de dagelijkse werking van organisaties uit deze sector. Aanhangers van deze visie op armoedebestrijding pleiten ervoor om naast de individuele begeleiding van werkzoekenden ook aandacht te hebben voor de structurele drempels in onze samenleving, die ervoor zorgen dat personen uit de kansengroepen minder kansen op de arbeidsmarkt krijgen. Uit mijn kwalitatief onderzoek blijkt echter dat structureel werken in de sociale economie niet evident is en bijgevolg ook

  7. Les édifices néogothiques parisiens et leurs verrières : églises et chapelles catholiques

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    Martine Callias Bey


    une technique très maîtrisée, qui cependant s’ouvre à des procédés nouveaux comme l’impression de motifs répétitifs sur les verres de bordure ou de fond. Considérant l’éclectisme architectural du XIXe siècle comme un style à part entière, il convient de qualifier de même ce mélange fréquent des styles, pas nécessairement cohérents, utilisés soit pour les personnages soit pour les encadrements dans les verrières dites « archéologiques » ou les « verrières-tableaux ».Despite the interest elicited by 19th century religious art over the past thirty years, Paris has lost much of its 19th century religious stained glass. It was urgent to carry out an inventory of what remains. The aim of this article is to present the Catholic Gothic revival buildings in Paris and their stained glass. The corpus comprises five parish churches, 19 congregational chapels or chapel transformed into parish churches, and two other ancillary buildings. A total of 526 stained-glass works was surveyed and studied; 286 are designs with figures, 37 of these classifiable as stained-glass picture compositions. The remaining 240 works are ornamental. Behind this production, we find some 22 different stained-glass producers, amongst the most important of which are Didron, Lusson, Champigneulle, Hirsch and Gsell. Paris played a leading role in the revival of stained glass during the early years of the 19th century, thanks in part to the perspicacious inspiration of certain figures in power, such as the Prefect of Paris, the Comte de Chabrol, who was at the origins of the ‘resurrection’ of the skill of stained-glass painters with the 1825 creation of the works at the Foire Saint-Laurent. Further inspiration came from the first restoration work carried out on older stained-glass works, and the decisive role of diocesan architects. The iconography of these works reflects the evolution of France’s religious life during the period, from the liberty of the Concordat to

  8. Intergranular Pressure Solution in Nacl: Grain-To-Grain Contact Experiments under the Optical Microscope Dissolution sous contrainte dans NaCl : expériences de contact grain à grain sous microscope optique

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    Spiers C. J.


    effective diffusivity varying with contact force and on-going convergence. The results agree broadly with those of previous compaction creep experiments performed using wet halite powder. Discrepancies with other workers results for single-contact dissolution experiments can be explained in terms of differences in experimental configuration and competition between driving forces. La dissolution sous contrainte (IPS - Intergranular Pressure Solution représente un mécanisme de lithification, de compaction et de déformation à l'échelle géologique pour une large gamme de roches. Les études expérimentales d'IPS réalisées sur des agrégats de quartz n'ont pas été couronnées de succès en raison d'un taux faible d'IPS, et les expériences IPS réalisées en utilisant une halite saturée comme analogue de roche (Spiers et Schutjens, 1990 ; Hickman et Evans, 1991 ont laissé des incertitudes quant au détail des mécanismes IPS et à la structure/saturation au contact du grain dans ce matériau. La présente étude fait état de quatre expériences de dissolution de contact réalisées sous microscope optique afin d'étudier le mécanisme et la cinétique de l'IPS pour des contacts simples halite/halite et halite/verre, chargés en eau salée (température ambiante. Des forces normales de contact dans la gamme de 1,0 à 2,6 N ont été appliquées en présence d'eau salée saturée en NaCl, induisant des pressions de 0,8 à 7,4 MPa. Des pertes de masse et des convergences - fonction du temps - ont été observées pour tous les contacts. Dans tous les cas, le fait de charger le contact (ou d'augmenter la charge sur le contact a conduit à la formation immédiate d'une morphologie de contact rugueuse, composée d'un motif d'îles et de canaux, contrôlé par des caractéristiques cristallographiques, à l'échelle de quelques microns. Cette microstructure non équilibrée a évolué dans le temps vers une face de contact optiquement plate. Le processus de convergence

  9. Étude de la mouillabilité des roches réservoir à l'échelle du pore par cryomicroscopie électronique à balayage Wettability of Reservoir Rock At the Pore Scale: Contribution of Cryo-Scanning Electron Microscopy

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    Fassi-Fihri O.


    Full Text Available Le but de cette étude est de caractériser, à l'échelle du pore, la mouillabilité des roches réservoir, en relation avec leur géométrie et/ou leur minéralogie. Cette caractérisation se fait, après congélation des échantillons, par l'observation de la distribution des fluides au sein du milieu poreux (saumure et huile brute, en microscopie électronique à balayage. Les expériences ont d'abord été effectuées sur des roches modèles parfaitement mouillables à l'eau, verre fritté et grès naturels. Certains de ces minéraux ont été rendus hydrophobes par greffage de silane. L'étude de ces systèmes a mis en évidence une corrélation entre la mouillabilité et la distribution des fluides. Puis, une roche réservoir (grès argileux de la formation de Brent, de mer du Nord connue comme étant de mouillabilité intermédiaire a été étudiée. Un travail précédent (étude de déplacements eau/huile par tomographie X avait abouti à la conclusion que si ces roches présentaient des hétérogénéités de mouillabilité, l'échelle de ces hétérogénéités devait être inférieure au millimètre. Les études de cryomicroscopie ont montré le caractère hydrophobe de la kaolinite, tandis que les illites, le quartz et les feldspaths sont préférentiellement mouillables à l'eau. L'imbibition spontanée d'huile pourrait ainsi être attribuée à l'existence au sein de la roche d'un réseau de kaolinite, tandis que l'imbibition spontanée de saumure serait due à l'existence d'un second réseau plus ou moins imbriqué avec le premier et constitué des autres minéraux. Un autre cas de roche réservoir a été étudié, à savoir un carbonate du Moyen-Orient. Les mésopores intergranulaires y ont été observés comme étant mouillables à l'huile tandis que les micropores restaient mouillables à l'eau. Dans ce cas, la mouillabilité intermédiaire de ces échantillons s'explique par la géométrie plutôt que par la min