5,000 research outputs found

    Compact Measurement Station for Low Energy Proton Beams

    Full text link
    A compact, remote controlled, cost efficient diagnostic station has been developed to measure the charge, the profile and the emittance for low energy proton beams. It has been installed and tested in the proton beam line of the Project Prometheus at SANAEM of the Turkish Atomic Energy Authority.Comment: 7 pages 2 column

    Electrode Fixation with Bone Cement or Stimloc (R) in Deep Brain Stimulation Surgery: A Comparative Study

    Get PDF
    AIM: To examine the postoperative outcomes of electrode fixation using bone cement and Stimloc?? in patients with Parkinson???s MATERIAL and METHODS: Between 2016 and 2018, permanent electrode fixation was performed in 30 patients with PD, of which 15 received bone cement and the remaining 15 received Stimloc??. Data regarding preoperative Unified Parkinson???s Disease Rating Scale (UPDRS) III scores, levodopa equivalent daily dose (LEDD) values, surgery duration, and the fixation technique used were recorded. Brain computed tomography was performed for early postoperative evaluation of pneumocephalus and possible hematoma as well as for the determination of migration 1 year postoperatively. UPDRS III scores and LEDD values were re-evaluated 1 year postoperatively; surgery duration, clinical effectiveness, and complication rates were compared between the two fixation techniques. RESULTS: A statistically significant difference in application time was observed between the two techniques (bone cement: 21 min, Stimloc??: 6 min). After 1 year from surgery, 0.92- and 0.88-mm migrations were observed in the bone cement and Stimloc?? groups, respectively. A significant correlation between migration and the pneumocephalus volume was observed in both groups. No differences were observed between the groups regarding infection, migration, pneumocephalus volume, wound erosion, and CONCLUSION: Stimloc?? is preferred over bone cement for electrode fixation in DBS surgeries as it is associated with shorter application duration; this increases patient comfort and tolerance during awake surgery. Clinical efficacy and complication rates associated with both techniques are similar

    Determination of trace elements in the plants of Mt. Bozdag, Izmir, Turkey

    Get PDF
    The aim of this study was to determine the current level of atmospheric heavy metal content on the Bozdag Mountain of the Aegean Region, Turkey. Twenty nine different plants were selected to study their potential as biomonitors of trace elements such as Ni, Zn, Fe, Pb, Mn and Cd (μg g-1, dry weight). The samples were collected from two different altitudes of Mt. Bozdag. The concentrations of trace elements were determined by atomic absorption spectrometry. The mean concentrations determined at 1000 m altitude ranged from 0.025 to 1.609, 0.232 to 0.731, 0.578 to 5.983, 0.287 to 0.565 and 0.176 to 2.659 (μg g-1, dry weight), for Ni, Zn, Fe, Pb and Mn, respectively. At the altitude of 1600 m, the values ranged from 0.023 to 0.939, 0.258 to 1.254, 0.839 to 5.176, 0.301 to 1.341 and 0.405 to 3.351 (μg g-1, dry weight) for Ni, Zn, Fe, Pb and Mn, respectively. No Cd was detected at either altitude. Statistical significance was determined by the independent sample t-test and comparisons were made in order to determine if there were any differences between the averages of herbaceous and woody plants.

    A comparative study on the abundance and elemental composition of POM in three interconnected basins: the Black, the Marmara and the Mediterranean Seas

    Get PDF
    The abundance and elemental composition of suspended particulate organic matter in the upper layers of the interconnected Mediterranean, Marmara and Black Seas having different ecosystems were determined in 1990-1998. The aim was principally to compare the C:N:P ratio of seston and understand factors controlling the seston composition in near- and off-shore waters of these seas. In the Marmara Sea, euphotic zone average particulate concentrations varied regionally and seasonally between 10-35 ìM for POC, 0.4-4.5 ìM for PON and 0.05-0.45 ìM for PP. These concentrations are mostly above the off-shore Black Sea values but much greater than those measured in the open waters of the north-eastern Mediterranean whose near-shore data are comparable with the seston content of the deep Black Sea. Comparison of C:N:P ratios of seston reveals that atmospheric and land-based phosphorus input influences the C:P and N:P ratios in the near-shore waters. Apparent nutrient deficiencies observed in the water column were not as remarkable in the elemental composition of seston. Unexpectedly, in the NE Mediterranean, N:P ratios from regression analyses of particulate data are very low (7-9) in the coastal region but slightly increase to levels of 10-15 in the open sea. In the Sea of Marmara, the N:P ratios (7-12) of seston are as low as in the Mediterranean, being consistent with the particulate ratios of the Black Sea inflow and NO3:PO4 ratios of the Marmara sub-halocline water. The Black Sea seston is relatively rich in carbonaceous compounds with N:P ratio ranging merely between 15-17 in the open sea but 9-27 in coastal waters where riverine discharges markedly influence the stoichiometry of seston

    Pulsed Beam Tests at the SANAEM RFQ Beamline

    Full text link
    A proton beamline consisting of an inductively coupled plasma (ICP) source, two solenoid magnets, two steerer magnets and a radio frequency quadrupole (RFQ) is developed at the Turkish Atomic Energy Authority's (TAEA) Saraykoy Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of 2016, the RFQ was installed in the beamline. The high power tests of the RF power supply and the RF transmission line were done successfully. The high power RF conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was tested in two different conditions, CW and pulsed. The characterization of the proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter. Beam transverse emittance was measured in between the two solenoids of the LEBT. The measured beam is then reconstructed at the entrance of the RFQ by using computer simulations to determine the optimum solenoid currents for acceptance matching of the beam. This paper will introduce the pulsed beam test results at the SANAEM RFQ beamline. In addition, the high power RF conditioning of the RFQ will be discussed.Comment: 6 pages, 6 figures. Proceedings of the International Particle Accelerator Conference 2017 (IPAC'17), May 14-19, 2017, TUPAB015, p. 134

    Color Reflection Invariance and Monopole Condensation in QCD

    Get PDF
    We review the quantum instability of the Savvidy-Nielsen-Olesen (SNO) vacuum of the one-loop effective action of SU(2) QCD, and point out a critical defect in the calculation of the functional determinant of the gluon loop in the SNO effective action. We prove that the gauge invariance, in particular the color reflection invariance, exclude the unstable tachyonic modes from the gluon loop integral. This guarantees the stability of the magnetic condensation in QCD.Comment: 28 pages, 3 figures, JHEP styl

    Enhanced catalytic performance of MnxOy-Na2WO4/SiO2 for the oxidative coupling of methane using an ordered mesoporous silica support

    Get PDF
    The oxidative coupling of methane is a highly promising reaction for its direct conversion. Silica supported MnxOy–Na2WO4 is a suitable catalyst for this reaction. In this study, a variety of different SiO2 materials have been tested as supports. Surprisingly, the application of ordered mesoporous silicas, here exemplarily shown for SBA-15 as support materials, greatly enhances the catalytic performance. The CH4 conversion increased two fold and also the C2 selectivity is strongly increased

    Исследование парогазовой установки, работающей на генераторном газе

    Get PDF
    Выпускная квалификационная работа 116 страниц, 25 рисунков, 25 таблиц, 35 источников, 2 приложения. Ключевые слова: газификация угля, парогазовая установка, газотурбинная установка, генераторный газ, анализ, котел-утилизатор, показатели эффективности. Объектом исследования является ПГУ, работающая на генераторном газе. Цель работы – анализ работоспособности такой ПГУ с ГТУ, работающей на генераторном газе. В процессе исследования проводилось изучение различных способов газификации угля; производился выбор расчетной схемы ПГУ с газификацией; проводился расчет состава и характеристик генераторного газа и определение основных показателей тепловой эффективности ПГУ. В результате исследования был сделан анализ эффективности работы парогазовой установки.Final qualifying work of 116 pages, 25 figures, 25 tables, 35 sources, 2 annexes. Keywords: coal gasification combined cycle plant, a gas turbine plant, the product gas analysis, waste heat boiler, performance indicators. The object of this study is to CCGT running on syngas. The purpose of work - performance analysis of a CCGT with a gas turbine, operating on syngas. The study was carried out to study different methods of coal gasification; selects the estimated PSU circuit with gasification; conducted calculation and composition of the product gas characteristics and the definition of the main indicators of the thermal efficiency of the CCGT. The survey was made the analysis of the efficiency of the combined-cycle plant
    corecore