Transport of argon ions in an inductively coupled high-density plasma reactor

The first direct observation of the velocity distribution of the metastable Ar1*~2G9/2! ions in the presheath of an inductively coupled plasma has been achieved by using the Doppler shifted laser induced fluorescence technique. Drift of the ions along the electric field in the presheath is observed and distribution functions of the velocity in both parallel and perpendicular directions, relative to the E field, are deduced at 5 and 40 mTorr. Present results show that in high density plasmas the velocity distribution of the metastable ions is directly related to that of the ground state argon ions. Neutral gas temperature of around 600 K is also measured from the absorption profile of a diode laser beam, set on one of the 772.4 nm argon lines

Application of pre-stressed un-bonded CFRP for strenghthening of metallic structures

Application of carbon fiber-reinforced polymer (CFRP) composites for retrofitting reinforced concrete structures has been extensively investigated and used in practice. Many studies demonstrated the beneficial influence of such composite materials for the flexural and shear strengthening of concrete girders, as well as for confinement of concrete columns. However, the strengthening techniques and the accompanying theories for metallic structures have not been developed as thoroughly as those for concrete structures. There are several differences between the behavior of bonded joints in CFRP-strengthened concrete and metallic members, which will be briefly explained in this paper. Furthermore, one of the main aims of the paper is to give an overview on different techniques for carbon-fibre reinforced polymer (CFRP) strengthening of steel plates and beams. Different bonded and un-bonded retrofit systems will be discussed with particular focus on application of pre-stressed un-bonded retrofit (PUR) systems. Furthermore, some details about design and testing procedure of a new so called flat PUR (FPUR) system will be given. Finally, the paper gives some details about CFRP strengthening and wireless sensor monitoring of two old metallic bridges in Switzerland and Australia

Neogeography and the democratization of GIS: a metasynthesis of qualitative research

Neogeography is the name given to the phenomenon of the vastly expanded Geographic Information Systems (GIS) user base. It consists of a collection of practices, tools and users generally found outside of traditional, authoritative GIS. GIS are computer applications that allow users to contribute geotagged data and to access and utilize geospatial data sets in combination with attribute information for a variety of purposes. This paper investigates questions of whether neogeography furthers the democratization of GIS and if increased access translates to empowerment or, conversely, to further marginalization. The research is interpretative and involves a literature review of the topic and a metasynthesis of recent qualitative research. Metasynthesis involves critical evaluation of data to identify an appropriate research sample and synthesis of findings by a compare-and-contrast exercise followed by reciprocal translation of each study into the other studies to reveal overarching metaphors. This is followed by conclusions and recommendations. The findings show that, depending on circumstances, neogeography can result in the democratization of GIS and geospatial data but may also constitute new methods of exclusion depending on technological and societal barriers. Neogeography can also result in empowerment, but this is difficult to define and is often highly contingent on local context

Enantioselective synthesis of polysubstituted prolines by Binap-silver-catalyzed 1,3-dipolar cycloadditions

The enantioselective 1,3-dipolar cycloaddition reaction of stabilized azomethine ylides, generated from iminoesters, with maleimides was efficiently achieved by intermediacy of an equimolar mixture of chiral (R)- or (S)-Binap and AgClO4. The high stability of the titled catalytic metal-complex to light exposure and its insolubility in toluene made possible its recovery and reutilization in other new process. In order to get a better understanding of the behavior of these chiral catalysts, we have carried out DFT1 calculations demonstrating the experimentally observed high enantio- and endo-selectivity through a very asynchronous transition state.This work has been supported by the DGES of the Spanish Ministerio de Educación y Ciencia (MEC) (Consolider INGENIO 2010 CSD2007-00006, CTQ2007-62771/BQU, and CTQ2004-00808/BQU), Generalitat Valenciana (CTIOIB/2002/320, GRUPOS03/134 and GV05/144), and by the University of Alicante. M.G. Retamosa thanks the University of Alicante for a predoctoral fellowship

Enantioselective synthesis of proline derivatives by 1,3-dipolar cycloadditions

Research devoted to the synthesis of highly substituted prolines, which are hepatitis C virus inhibitors, using 1,3-dipolar cycloadditions (1,3-DC) of azomethine ylides is described. In the first part, a diastereoselective approach using an inexpensive lactate-derived acrylate as dipolarophile is described. In the second part, our efforts using simple and easily accessible chiral silver(I) and gold(I) complexes as catalysts for enantioselective synthesis of proline derivatives are reviewed. In this case, chiral phosphoramidites and binap have been used as privileged ligands. Parallel to these experimental results, considerable effort was dedicated to run semiempirical density functional theory (DFT) calculations to explain and justify the stereoselectivity of each process.This work has been supported by the DGES of the Spanish Ministerio de Ciencia e Innovación (MICINN) (Consolider INGENIO 2010 CSD2007-00006, FEDER-CTQ2007-62771/BQU, and by the Hispano-Brazilian project PHB2008-0037-PC), Generalitat Valenciana (PROMETEO/2009/039), and by the University of Alicante (GITE-09020-UA)