Study of the Interactions between Elodea canadensis and CuO Nanoparticles

Copper is one of the key heavy metals that pollute environment and constitute a serious threat to thehealth of humans and ecosystems. Copper may enter the aquatic environment in both soluble and nanoparticleform. It was previously found in a series of studies that nanoparticles, including those of several metal oxides,exercise both negative and positive effects on the higher plants which makes necessary further research on theinteraction between metal oxide nanoparticles and plants. Interactions between aquatic plants and copper–containingnanoparticles were not suffi ciently studied. The goal of this study was to contribute to the investigation of theinteractions between CuO nanoparticles and the aquatic plant Elodea canadensis under the conditions of experimentalmicrocosms. It was found that CuO nanoparticles demonstrated some phytotoxicity to Elodea canadensis.After the incubation of Elodea canadensis in the aquatic medium contaminated with CuO nanoparticles there wasa signifi cant increase (by two orders of magnitude) of the concentration of copper in the biomass of the plants

Immobilization of Scandium and Other Chemical Elements in Systems with Aquatic Macrophyte

The possibility of immobilization of scandium and other chemical elements by biogenic materialsderived from an aquatic macrophyte was explored. The concentrations of scandium and some other chemicalelements were measured in the dried biomass (mortmass) of aquatic plants Myriophyllum aquaticum. In theexperiments, the mortmass was incubated in aquatic systems where some chemical elements were added to theaquatic medium. After the incubation, the concentrations of these chemical elements in the mortmass weremeasured using inductively coupled plasma atomic emission spectroscopy (ICP-AES), also referred to asinductively coupled plasma optical emission spectrometry (ICP-OES). Increases in the concentrations ofscandium and some other chemical elements (Ce, In, Se, Ru, Pd, U, and Zr) were observed in the biogenic materia

Feasibility study of a 2 GeV superconducting H−H^{-} linac as injector for the CERN PS

This preliminary feasibility study is based on the availability of the CERN LEP2 superconducting RF system after LEP de-commissioning. The option that is explored is to use this system as part of a high energy H- linac injecting at 2 GeV into the CERN PS, with the aim of reliably providing at its output twice the presently foreseen transverse beam brightness at the ultimate intensity envisaged for LHC. This requires the linac to be pulsed at the PS repetition rate of 0.8 Hz with a mean beam current of 10 mA which is sufficient for filling the PS in 240 ms (i.e. about 100 turns) with the ultimate intensity foreseen for injection for the LHC. The linac is composed of two RFQs with a chopping section, a room temperature DTL, a superconducting section with reduced beta cavities up to 1 GeV, and a section of LEP2 cavities up to 2 GeV. This study deals, in particular, with the problems inherent in H- acceleration up to high energy and in the pulsed operation of SC cavities. Means for compensating microphonic vibrations in the SC cavities are considered, with the aim of reducing the final overall energy spread to the tight requirements for injection into a synchrotron. Other possible applications of such a machine are also briefly reviewed, that make use of its potential for working at a higher duty cycle than required for LHC alone

Abordagem contextual nos capítulos de estequiometria e de soluções dos livros didáticos de Química aprovados pelo PNLD (Programa Nacional do Livro Didático - Brasil) /2012

A contextualização tem sido proposta no currículo escolar com o propósito de promover mudanças de comportamentos, atitudes e valores. Nessa abordagem, entende-se que o ensino de química deve se desenvolver de forma ampla, envolvendo também aspectos sociais, políticos, econômicos,ambientais e culturais, e não somente aspectos científicos. Tendo em vista a grande importância dada ao livro didático (LD) na prática docente, buscamos analisar a abordagem contextual nos capítulos de estequiometria e soluções nos LD de química aprovados pelo PNLD/2012. Os resultados mostraram que os autores dos LD analisados reconhecem a contextualização como elemento central para a formação da cidadania, porém a abordagem é diferente em cada obra. As leituras dos LD possibilitaram a identificação de alguns "níveis" de contextualização que percorreram quatro categorias de análise

Report of the study group on a superconducting proton linac as a PS Injector

A proposal was made at the end of 1996 to use the large inventory of RF hardware available after the decommissioning of LEP-2 for the construction of a 2 GeV Superconducting Proton Linac (SPL) to inject directly into the PS [1.1]. The brightness of the beam in the PS at low energy would double, helping the injector complex to satisfy the requirements of the LHC and benefiting the planned proton physics programme. Additional users could also be accommodated thanks to the capability of the SPL to operate at a much larger duty factor than that required for high-energy physics. Consequently, a small study group has been set up to analyse the major technical aspects of the SPL design as well as the processes of injection and capture in the PS. This report summarises the work done so far, and provides some information about the other possible uses of the SPL beam. The feasibility of such a cascade of accelerators is confirmed, although an in-depth design study is still required before the realistic performance and detailed design of that facility can be announced

Science Requirements and Conceptual Design for a Polarized Medium Energy Electron-Ion Collider at Jefferson Lab

This report presents a brief summary of the science opportunities and program of a polarized medium energy electron-ion collider at Jefferson Lab and a comprehensive description of the conceptual design of such a collider based on the CEBAF electron accelerator facility.Comment: 160 pages, ~93 figures This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177, DE-AC02-06CH11357, DE-AC05-060R23177, and DESC0005823. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purpose

Advanced surface treatments for medium-velocity superconducting RF cavities for high accelerating gradient continuous-wave operation

Nitrogen-doping and furnace-baking are advanced high-Q0 recipes developed for 1.3 GHz TESLA-type cavities. These treatments will significantly benefit the high-Q0 linear accelerator community if they can be successfully adapted to different cavity styles and frequencies. Strong frequency- and geometry- dependence of these recipes makes the technology transfer amongst different cavity styles and frequencies far from straightforward, and requires rigorous study. Upcoming high-Q0 continuous-wave linear accelerator projects, such as the proposed Michigan State University Facility for Rare Isotope Beam Energy Upgrade, and the underway Fermilab's Proton Improvement Plan-II, could benefit enormously from adapting these techniques to their beta_opt = 0.6 ~650 MHz 5-cell elliptical superconducting rf cavities, operating at an accelerating gradient of around ~17 MV/m. This is the first investigation of the adaptation of nitrogen doping and medium temperature furnace baking to prototype 644 MHz beta_opt = 0.65 cavities, with the aim of demonstrating the high-Q0 potential of these recipes in these novel cavities for future optimization as part of the FRIB400 project R&D. We find that nitrogen-doping delivers superior Q0, despite the sub-GHz operating frequency of these cavities, but is sensitive to the post-doping electropolishing removal step and experiences elevated residual resistance. Medium temperature furnace baking delivers reasonable performance with decreased residual resistance compared to the nitrogen doped cavity, but may require further recipe refinement. The gradient requirement for the FRIB400 upgrade project is comfortably achieved by both recipes.Comment: 16 pages, 5 figure