4,371 research outputs found

    Influence of the anion specificity on the anodic polarization of titanium

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    The anodic polarization of titanium in the presence of selected electrolytes at 0.1 mol/L concentration has been investigated. The results were interpreted according to the categorization of anions based on their cosmotrope/chaotrope character. The aggressiveness of the anions is found to be related for a part to their proneness to loose their hydration shell during the penetration of the passive film, provided they can access sufficiently to the passive surface

    Influence of the anion specificity on the electrochemical corrosion of anodized aluminum substrates

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    The electrochemical corrosion of anodized aluminum substrates in the presence of various electrolyte solutions at 0.01 mol L−1 concentration has been investigated. The comparative results were found to exhibit a correlation between the aggressiveness of the anions and their cosmotrope/chaotrope nature. The origin of the observed behavior was assumed to result from a variable resistance against dehydration during the pitting process

    Overview of the mean of production used for FSW

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    The Friction Stir welding process is now introduced in production plants. More and more applications are developed and the most part of the work is now centered on the mean of production to be used. Institut de Soudure and Arts et Métiers ParisTech are working on this subject since mid of 2005. The results of this work is a recognize knowledge on the methodology for qualifying a Friction Stir Welding Equipment [1]. In the same time, and based on this work, Institut de Soudure has bought a new kind of Friction Stir Welding machine based on a KUKA Robot

    Experimental investigation of the influence of the FSW plunge processing parameters on the maximum generated force and torque

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    The paper presents the results of an experimental investigation, done on the friction stir welding (FSW) plunging stage. Previous research works showed that the axial force and torque generated during this stage were characteristic for a static qualification of a FSW machine. Therefore, the investigation objectives are to better understand the relation between the processing parameters and the forces and torque generated. One of the goals is to find a way to reduce the maximum axial force and torque occurring at the end of the plunging stage in order to allow the use of a flexible FSW machine. Thus, the influence of the main plunge processing parameters on the maximum axial force and torque are analysed. In fact, forces and torque responses can be influenced by the processing parameter. At the end, a diagram presenting the maximum axial force and torque according to the processing parameters is presented. It is an interesting way to present the experimental results. This kind of representation can be useful for the processing parameters choice. They can be chosen according to the force and torque responses and consequently to the FSW machine capacities

    Statistical model of the tool/workpiece mechanical interactions in FSW

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    The robotization of the FSW process is facing two challenges which are to support the amplitude of the tool / workpiece mechanical interaction generated by welding and to apply the process parameters and in particular the axial force. To design the control laws of the robot it is necessary to model the mechanical interaction between the tool and the workpiece as function of the fsw process parameters

    Decompletion of cyclotomic perfectoid fields in positive characteristic

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    Let EE be a field of characteristic pp. The group Zp×\mathbf{Z}_p^\times acts on E((X))E((X)) by af(X)=f((1+X)a1)a \cdot f(X) = f((1+X)^a-1). This action extends to the XX-adic completion E~\tilde{\mathbf{E}} of n0E((X1/pn))\cup_{n \geq 0} E((X^{1/p^n})). We show how to recover E((X))E((X)) from the valued EE-vector space E~\tilde{\mathbf{E}} endowed with its action of Zp×\mathbf{Z}_p^\times. To do this, we introduce the notion of super-H\"older vector in certain EE-linear representations of Zp\mathbf{Z}_p. This is a characteristic pp analogue of the notion of locally analytic vector in pp-adic Banach representations of pp-adic Lie groups.Comment: v3: final version, accepted for publication in Annales Henri Lebesgue. Prop 3.2.9 and coro 3.2.10 are new. v2: added remarks 1.1.5 (an example), 1.2.7 (related work of Rodriguez Camargo), 1.3.4 (related work of Gulotta and Johansson-Newton) and 3.2.9 (exercise for the reader

    A quantitative ecological study of selected nearshore marine plants and animals at the Diablo Canyon power plant site: a pre-operational baseline, 1973-1978

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    Biologists of the California Department of Fish and Game, under contract with the Pacific Gas and Electric Company, conducted surveys or intertidal and subtidal plants and animals 1n the vicinity of the Diablo Canyon Nuclear Power Plant for the summer of 1973 through 1978. Abundances of the dominant plants and animals were obtained at random as well as permanent stations in Diablo Cove as well as nearby control areas. A total of 643 permanent and random stations were surveyed, 262 in the intertidal and 381 in the subtidal. Natural as well as man-caused occurrences have resulted in several significant changes in plant and animal abundance in the study areas; these include the arrival of the southern front or the sea otter population in Diablo Cove in 1974; a strong red tide bloom in the fall of 1974; and the release of copper ions from the power plant condenser tubes into Diablo Cove during the summer of 1974. Our intertidal and subtidal random station data have shown a strong decline in giant red sea urchin, Strongylocentrotus franciscanus, densities and the surface canopy kelp, Nereocystis/leutkeana, and a corresponding increase in the subcanopy kelps, Pterygophora and Laminaria. Seasonal patterns of abundance of foliose red algae at random intertidal stations occurred at all study areas. Several species intertidal and subtidal invertebrates showed increasing or decreasing trends in levels of abundance during the five year study period covered by the report. Some of these changes in abundance may be related to the natural man-caused impacts mentioned above. (Document has 728 pages
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