1,148 research outputs found
Studies of Intermediate Vector Boson Production at the CERN Proton-Antiproton Collider
No full textAn extensive study of production and decay
properties of charged and neutral Intermediate Vector
Bosons (IVB) at the CERN proton-antiproton
collider is presented. Intermediate Vector Bosons were detected in the electron, muon, and tau decay
modes at centre-of-mass energies of 0.546 and
0.630 TeV. This paper is a summary, based on all
the available data from the UA1 experiment
Measurement of momentum and angular distributions of punchthrough muons with the RD5 experiment
No full textNorth American import? Charting the origins of an enigmatic Trypanosoma cruzi domestic genotype.
No full textBACKGROUND: Trypanosoma cruzi, the agent of Chagas disease, is currently recognized as a complex of six lineages or Discrete Typing Units (DTU): TcI-TcVI. Recent studies have identified a divergent group within TcI - TcI(DOM). TcI(DOM). is associated with a significant proportion of human TcI infections in South America, largely absent from local wild mammals and vectors, yet closely related to sylvatic strains in North/Central America. Our aim was to examine hypotheses describing the origin of the TcI(DOM) genotype. We propose two possible scenarios: an emergence of TcI(DOM) in northern South America as a sister group of North American strain progenitors and dispersal among domestic transmission cycles, or an origin in North America, prior to dispersal back into South American domestic cycles. To provide further insight we undertook high resolution nuclear and mitochondrial genotyping of multiple Central American strains (from areas of México and Guatemala) and included them in an analysis with other published data. FINDINGS: Mitochondrial sequence and nuclear microsatellite data revealed a cline in genetic diversity across isolates grouped into three populations: South America, North/Central America and TcI(DOM). As such, greatest diversity was observed in South America (A(r) = 4.851, π = 0.00712) and lowest in TcI(DOM) (Ar = 1.813, π = 0.00071). Nuclear genetic clustering (genetic distance based) analyses suggest that TcI(DOM) is nested within the North/Central American clade. CONCLUSIONS: Declining genetic diversity across the populations, and corresponding hierarchical clustering suggest that emergence of this important human genotype most likely occurred in North/Central America before moving southwards. These data are consistent with early patterns of human dispersal into South America
Design, Test and Analysis of a Gyrotron Cavity Mock-Up Cooled Using Mini Channels
No full textIn 2016, we have designed, built and finally tested at the FE200 facility in Le Creusot (France) a planar mock-up mimicking the water-cooled cylindrical resonance cavity of the European 170 GHz, 1 MW gyrotron to be used for electron cyclotron plasma heating in ITER. The aim of the mock-up is the characterization of the cooling capability of the cavity. A Glidcop® target is heated with an electron beam gun with resulting peak heat fluxes relevant for the full-size cavity. Underneath the target surface, whose temperature is monitored by means of a pyrometer, a set of parallel semi-circular mini-channels, with diameter of 1.5 mm, allows the flow of pressurized water, entering the mockup at ~ 9 bar and 40 °C. Several thermocouples measure the target temperature, at different distances from the heated target surface. The experimental results show that the mock-up is capable to withstand a heat fluxes of 21 MW/m2, while the cooling system keeps the heated surface below ~ 400 °C, for flow conditions comparable to those of the full-size cavity. The test results are used to first calibrate the uncertain model parameters and then, with frozen parameters, to validate a previously developed CFD model, showing good agreement with the experiment. In view of its reliability, this model might eventually be a useful tool for the simulation of the full-size gyrotron cavity operation
Analysis of an actively-cooled coaxial cavity in a 170 GHz 2 MW gyrotron using the multi-physics computational tool MUCCA
No full textContinuous Wave gyrotrons are the key elements for Electron Cyclotron Resonance Heating and Current Drive(ECRH&CD) in present fusion experiments and future fusion reactors. In the frame of the EUROfusion activities,a 170 GHz, 2 MW short-pulse (∼1 ms), water-cooled coaxial gyrotron, already tested at Karlsruhe Institute ofTechnology (KIT), is being upgraded for operation at longer pulses (∼100–1000 ms).Here we use the MUlti-physiCs tool for the integrated simulation of the CAvity (MUCCA), recently developedin collaboration between Politecnico di Torino and KIT, to analyze the evolution of the operating condition ofthe coaxial gyrotron cavity, self-consistently coupling thermal-hydraulic, thermo-mechanical and electro-dy-namic models. The main results are presented in terms of evolution of temperature, heat load and deformation ofthe heated surface of the resonator and of the coaxial insert during thefirst few seconds of operation. We showthat the system evolves towards stable operating conditions (no beam loss), with a peak temperature stronglydependent on the cooling configuration, where a large room for the improvement of the current cavity coolingdesign is found.1. IntroductionIn the EU-DEMO perspective [1], high power coaxial-cavity gyro-trons for heating the plasma and for driving a non-inductive currentinto it are under development at the Karlsruhe Institute of Technology(KIT) within the framework of EUROfusion activities [2]. The aim is toextend the∼1 ms pulse length of the existing 170 GHz, 2 MW coaxial-cavity tube up to 1 s [3,4]. Fig. 1shows the cross section of the bottompart of the 170 GHz, 2 MW gyrotron which is characterized by thepresence, inside the∼150 mm long cavity, of the coaxial insert (∼1200 mm long, in total). The high-frequency wave is generated insidethe cavity by resonant interaction between the electron beam, producedby a Magnetron Injection Gun (MIG) at the lower part of the gyrotron,and the high-frequency electromagneticfield in the cavity [5].A very high ohmic heat-load results on the cavity and insert sur-faces; therefore, both are subject to a deformation that modifies theresonating volume and changes the working condition of the gyrotron.A forcedflow of pressurized subcooled water, passing around the re-sonator as well as through the insert by means of two independentcooling circuits, is used to maintain the cavity region as cold as possibleto avoid damages (Tmax< 250 °C) and to reduce the thermal de-formation of the surfaces.2. Description of the coaxial cavity geometryThe cross section of the cavity and coaxial insert are shown inFig. 2a, where the internal structure of the two components is alsodisplayed.The cavity is made of two different regions: the resonator and theexternal structure. The coolantflows in the annular region between theresonator and the external structure (seeFig. 2a, blue arrows) and exitsfrom the outlet pipe on the top–inlet and outlet pipe are located onopposite parts of the cavity, inducing a non-fully uniform massflowaround the cavity. The part of the coaxial insert, which is simulated inthis work is shown in purple inFig.2a. The main coolant pathway in thetop region of the coaxial insert is described by blue arrows inFig. 2b.The waterflows toward the upper region of the insert in the innerchannel, then moves to the external region by means of four rectangular
Multi-physics analysis of a 1MW gyrotron cavity cooled by mini-channels
No full textThe interaction cavity of the European 170 GHz, 1 MW Continuous Wave (CW) gyrotron for ITER, whichcould also be water-cooled using mini-channels as recently proposed, experiences during operation avery large heat load (>15 MW/m2) localized on a very short (<1 cm) axial length. Such heat loads aretypical for high power gyrotrons.As the thermal deformation of the cavity influences the electromagnetic field structure and con-sequently the gyrotron operation, the analysis of the cavity performance requires the simultaneoussolution of the coupled thermal-hydraulic, thermo-mechanic and electro-magnetic fields. In this paper,the thermal behaviour of the cavity under nominal heat load is computed first by CFD. Then a 3Dthermo-mechanical model of the cavity is developed, based on the temperature maps computed byCFD, to evaluate the resulting deformation of the inner cavity surface. Finally the deformation is usedto compute the updated heat load coming from the electromagnetic field generated by the electronbeam in the deformed cavity, which becomes the input for a new iteration of the thermal-hydraulic,thermal-mechanical and electromagnetic analyses. It is shown that this iterative procedure converges toa self-consistent heat-load/temperature-field/deformation-field picture in nominal operating conditions,without exceeding a temperature of ∼230◦C on the inner surface of the cavity
sj-docx-3-wso-10.1177_17474930231203133 – Supplemental material for Iatrogenic cerebral amyloid angiopathy: A multinational case series and individual patient data analysis of the literature
No full textSupplemental material, sj-docx-3-wso-10.1177_17474930231203133 for Iatrogenic cerebral amyloid angiopathy: A multinational case series and individual patient data analysis of the literature by Slaven Pikija, Janja Pretnar-Oblak, Senta Frol, Branko Malojcic, Thomas Gattringer, Kinga Rak-Frattner, Dimitre Staykov, Andrea Salmaggi, Riccardo Milani, Jozef Magdic, Sarah Iglseder, Eugen Trinka, Theo Kraus, Andreea Toma, Jacopo C. DiFrancesco, Payam Tabaee Damavandi, Natalia Fabin, Anna Bersano, Patricia de la Riva Juez, Ines Albajar Gomez, Benedetta Storti and Simon Fandler-Höfler in International Journal of Stroke</p
sj-docx-1-wso-10.1177_17474930231203133 – Supplemental material for Iatrogenic cerebral amyloid angiopathy: A multinational case series and individual patient data analysis of the literature
No full textSupplemental material, sj-docx-1-wso-10.1177_17474930231203133 for Iatrogenic cerebral amyloid angiopathy: A multinational case series and individual patient data analysis of the literature by Slaven Pikija, Janja Pretnar-Oblak, Senta Frol, Branko Malojcic, Thomas Gattringer, Kinga Rak-Frattner, Dimitre Staykov, Andrea Salmaggi, Riccardo Milani, Jozef Magdic, Sarah Iglseder, Eugen Trinka, Theo Kraus, Andreea Toma, Jacopo C. DiFrancesco, Payam Tabaee Damavandi, Natalia Fabin, Anna Bersano, Patricia de la Riva Juez, Ines Albajar Gomez, Benedetta Storti and Simon Fandler-Höfler in International Journal of Stroke</p
- …
