144 research outputs found

    Pulp Production by Acetosolv Process

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    Cellulose is the most abundant organic polymer on Earth and a fascinating compound for a vast variety of applications. It is mostly received from wood, thus it is a renewable resource and a CO2 storing material. One of the most important cellulose products are pulp and paper. The major goal of this work was to obtain a material with a high amount of cellulose through a pulping process of wood. Therefore, it is necessary to separate the wood bers and to remove a component of wood, which is called lignin (deligni cation). The conventional way to delignify wood is the Kraft process that causes serval problems like contamination of lignin with sulfur and the emission of toxic volatile sulfur compounds. Hence, there are alternative processes without sulfur, such as the Acetosolv process. It uses simple chemicals like acetic acid and is easy to handle. After cutting a spruce tree (Picea abies L. Karst.), debarking and chipping, the wood chips were cooked in the laboratory. The research included the chemical analysis of the obtained pulp and the manufacturing and testing of paper sheets. The yield of pulp ranged widely due to the di erent parameters of the cooking. FT-IR and Raman spectroscopy were used to observe the decrease of aromatic substances (lignin) and the acetylation of the pulp. With the means of Design of Experiments and statistical analysis the most important factors were identi ed and a mathematical regression model was calculated. The manufactured paper sheets showed good mechanical properties and high transparency. Finally, the Acetosolv process could be considered as a contribution to the upcoming bio-based economy because, in addition to the cellulose bers, the industry would be capable of adding value utilization of the separated lignin. It could be one step to a more sustainable paper and pulp production

    A New Cleanroom With Facilities for Cleaning and Assembly of Superconducting Cavities at Helmholtz-Institut Mainz

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    The Helmholtz-Institut Mainz HIM will operate a clean room facility for the assembly and possible re-treatment of superconducting cavities. This is mandatory for several SRF accelerator projects, like the advanced demonstrator for a dedicated sc heavy ion cw-linac at HIM or other projects pursued by research facilities or universities close by. While the installation of the clean room is in progress, the procurement of the appliances is ongoing. The present equipment planned and the current status of the installation will be presented

    Further R&D For A New Superconducting Cw Heavy Ion Linac@GSI

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    A low energy beam line (1.4 MeV/u) behind the GSI High Charge State Injector (HLI) will provide cw-heavy ion beams with high beam intensity. It is foreseen to build a new cw-heavy ion LINAC for post acceleration up to 7.3 MeV/u. In preparation an advanced R&D program isdefined: The first LINAC section (financed by HIM andpartly by HGF-ARD-initiative) comprising a sc CH-cavity embedded by two sc solenoids will be tested in2014/15 as a demonstrator. After successful testing theconstruction of an advanced cryo module comprising fourCH cavities is foreseen. As an intermediate step towardsan entire cw-LINAC the use of a double of two CH-cavities is planned: A short 5 cell cavity should bemounted directly behind the demonstrator cavity inside ashort cryostat. The design of the cw LINAC based onshorter sc CH-cavities would minimize the overalltechnical risk and costs. Besides with this cavity anoptimized operation of the whole LINAC especially withrespect to beam quality could be achieved. Last but notleast the concept of continuous energy variation applyingphase variation between the two cavities with constantbeta profile could be tested

    UNILAC Upgrades for Coulomb Barrier Energy Experiments

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    The GSI linear accelerator UNILAC provides heavy ion beams at Coulomb barrier energies for search and study of super heavy elements. Typical cross-sections of 55 fb require beam doses of 1.4·10¹⁹ according to a beam time of 117 days. Several upgrades will reduce the beam time to only 16 days. A second injection branch with a 28GHz-MS-ECRIS anticipates a factor of 10 in particle intensity. By a new cw rfq-structure all accelerator tanks are suitable for a duty cycle of at least 50% instead of 25% presently. Due to this, thermal power increase of 19 rf-amplifiers eased by higher ion charge states of the ECRIS is necessary. Finally the UNILAC timing system controlling 50Hz pulse-to-pulse operation of up to six beams differing in ion species and energy has to be modified considering beam diagnostics electronics and pulsable magnets. The front end comprising ECRIS, rfq- and IH-structure is cw suitable and will serve as injector for a new future sc-cw-linac

    Superconducting CH Cavities for Heavy Ion Acceleration

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    To demonstrate the operation ability of superconducting (sc) Crossbar-H-mode (CH) cavity technology a 217 MHz structure of this type is under development at the Institute for Applied Physics (IAP) of Frankfurt University. The cavity has 15 accelerating cells and a design beta of 0.059. It will be equipped with all necessary auxiliaries like a 10 kW power coupler and a tuning system. Currently, the cavity is under construction. Furthermore, this cavity will serve as demonstrator for a sc continuous wave (cw) LINAC at GSI. The proposed cw LINAC is highly requested to fulfil the requirements of nuclear chemistry and especially for a competitive production of new Super Heavy Elements (SHE) in the future. A full performance test by injecting and accelerating a beam from the GSI High Charge Injector (HLI) is planned in 2014. The current status of the sc CH cavity and the demonstrator project is presented
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