28 research outputs found
The Vocational Education in the Context of Decentralization of Power in Ukraine: Achievements and Threats
The article is aimed at analyzing and estimating the achievements and threats to the development of vocational education in the context of decentralization of power, defining of directions of improvement of efficiency of administration of vocational education in Ukraine. The status of vocational education development is analyzed, achievements and threats to the development of vocational education are identified. The necessity of decentralization of education administration is substantiated and, on the basis of studying of foreign experience and system analysis of legislative initiatives of the profile ministry, a number of directions of improvement of administration efficiency of vocational education in Ukraine are proposed (introduction of a new model of financing; change of administration system of vocational education; activation of local self-government bodies on administration and financing of vocational education; development of dual form of education and others). Prospect for further research in this direction is to estimate the financial and non-financial benefits of reforming the vocational education for employees, employers, regions, and the State
Coated conductor technology for the beamscreen chamber of future high energy circular colliders
The surface resistance of state-of-the-art REBa2Cu3O7-x coated conductors has been measured at 8 GHz versus temperature and magnetic field. We show that the surface resistance of REBa2Cu3O7-x strongly depends on the microstructure of the material. We have compared our results to those determined by the rigid fluxon model. The model gives a very good qualitative description of our data, opening the door to unravel the effect of material microstructure and vortex interactions on the surface resistance of high temperature superconductors. Moreover, it provides a powerful tool to design the best coated conductor architecture that minimizes the in-field surface resistance. We have found that the surface resistance of REBa2Cu3O7-x at 50 K and up to 9 T is lower than that of copper. This fact poses coated conductors as strong candidate to substitute copper as a beamscreen coating in CERN's future circular collider. To this end we have also analyzed the secondary electron yield (SEY) of REBa2Cu3O7-x and found a compatible coating made of sputtered Ti and amorphous carbon that decreases the SEY close to unity, a mandatory requirement for the beamscreen chamber of a circular collider in order to prevent the electron-cloud phenomenon.Peer ReviewedPostprint (author's final draft
RF characterisation of new coatings for future circular collider beam screens
For the future high energy colliders being under the design at this moment, the choice of a low surface impedance beam screen coating material has become of fundamental importance to ensure sufficiently low beam impedance and consequently guaranteed stable operation at high currents. We have studied the use of high-temperature superconducting coated conductors as possible coating materials for the beam screen of the FCC-hh. In addition, amorphous carbon coating and laser-based surface treatment techniques are effective surface treatments to lower the secondary electron yield and minimise the electron cloud build-up. We have developed and adapted different experimental setups based on resonating structures at frequencies below 10 GHz to study the response of these coatings and their modified surfaces under the influence of RF fields and DC magnetic fields up to 9ÂżT. Taking the FCC-hh as a reference, we will show that the surface resistance for REBCO-CCs is much lower than that of Cu. Further we show that the additional surface modifications can be optimised to minimise their impact on the surface impedance. Results from selected coatings will be presented.Work supported by CERN under Grants FCC-GOV-CC-0210 (KE4945/ATS), FCC-GOV-CC-0209 (KE4946/ATS) and FCC-GOV-CC0208 (KE4947/ATS). ICMAB funding through RTI2018-095853-B-C21 SuMaTe from MICINN and co-financing by the European Regional Development Fund, 2017-SGR 1519 from Generalitat de Catalunya, and COST Action NANOCO-HYBRI (CA16218) from EU, the Center of Excellence award Severo Ochoa CEX2019-000917-S. UPC funding through the Unit of Excellence Maria de Maetzu MDM2016-0600. N. Tagdulang and A. Romanov acknowledge MSCA-COFUND-2016-754397 for the PhD grant.Peer ReviewedPostprint (published version
Evaluation of the nonlinear surface resistance of REBCO coated conductors for their use in the FCC-hh beam screen
To assess the feasibility of using high-temperature superconductors for the beam screens of future circular colliders, we have undertaken a study of the power dependence of the microwave surface resistance in state-of-the-art REBCO coated conductors at about 8 GHz and 50 K. We have employed a dielectric resonator to produce radio-frequency (RF) electromagnetic fields on the surface of the coated conductors having amplitudes similar to those generated by proton bunches circulating in the vacuum chamber of the proposed future circular collider Hadron-Hadron (FCC-hh) at CERN We show that surface resistances in REBCO coated conductors without artificial pinning centers are more affected by a RF magnetic field than those containing nano-inclusions. Despite that, at 8 GHz, 50 K, and 9 T, most REBCO coated conductors studied outperform copper in terms of surface resistance, with the best sample having a 2.3 mΩ surface resistance while being subject to an RF field 2.5 times stronger than that in the FCC-hh. We also extrapolate the measured data to 16 T and 1 GHz, the actual FCC-hh dipole magnetic field, and the mid-beam frequency spectrum, demonstrating the possibility of lowering the surface resistance of the vacuum chamber by up to two orders of magnitude compared to copper. Further, we discuss the correlation between the time structure of the electromagnetic fields provided by vector network analyzers compared to the proton bunches' time structure in the collider and present the effect of low alternating magnetic fields on vortex displacement and the possibility of demagnetization of superconducting samples.The authors acknowledge the support and samples provided by Bruker HTS GmbH, Fujikura Ltd, SuNAM CO Ltd SuperOx, SuperPower Inc. and Theva DĂŒnnschichttechnik GmbH. This work was supported by CERN under Grant Nos. FCC-GOV-CC-0072/KE3358, FCC-GOV-CC-0153/KE4106 and FCC-GOV-CC-0208/KE4947/ATS. UPC funding was also provided through the Unit of Excellence MarĂa de Maeztu MDM2016-0600. N Tagdulang and A Romanov acknowledge MSCA-COFUND-2016-754397 for the PhD Grant. ICMAB authors acknowledge RTI2018-095853-B-C21 SuMaTe from MICINN and co-financing by the European Regional Development Fund; 2017-SGR 1519 from Generalitat de Catalunya and COST Action NANOCO-HYBRI (CA16218) from EU, the Center of Excellence award Severo Ochoa CEX2019-000917-S.With funding from the Spanish government through the âSevero Ochoa Centre of Excellenceâ accreditation (CEX2019-000917-S).Peer reviewe
Superconducting Coated Conductors for Proton Beam Screens in High-Energy Particle Accelerators
A fi d'impulsar la investigaciĂł de la fĂsica d'altes energies mĂ©s enllĂ de la vida Ăștil del Gran Col·lisionador d'Hadrons (LHC), l'OrganitzaciĂł Europea per a la Recerca Nuclear (CERN) va iniciar una iniciativa de R + D per a un col·lisionador de protons de 100 TeV amb 100 km de circumferĂšncia, l'anomenat Future Circular Collider (FCC). Part de l'estudi del FCC Ă©s repensar el disseny de la pantalla del feix de protons, un component de l'accelerador que allotja el feix de protons i protegeix tĂšrmicament els imants superconductors de la radiaciĂł de sincrotrĂł. El concepte de la pantalla del feix de protons del LHC es basa en un tub d'acer inoxidable recobert al seu interior amb coure. No obstant aixĂČ, en les condicions operatives previstes pel FCC, Ă©s a dir, temperatures d'entre 40-60 K, sota camps magnĂštics de 16T i amb corrents induĂŻts a la pantalla del feix de 0-1 GHz, Ă©s possible que el recobriment de coure no mostri una impedĂ ncia superficial prou baixa per garantir un feix de protons estable. L'Ășnica classe de material coneguda que presenta menys resistĂšncia superficial en determinades condicions, Ă©s la formada pels superconductors. Des del gener del 2017, el grup de Materials Superconductors i Nanoestructures a Gran Escala de l'Institut de CiĂšncia de Materials de Barcelona (ICMAB-CSIC) va iniciar una col·laboraciĂł amb el CERN per avaluar la idoneĂŻtat i optimitzaciĂł de les cintes superconductores (CC, una estructura que consisteix en una capa de material superconductor sobre un substrat metĂ l·lic flexible) de REBa2Cu3O7 (RE = terres rares), com una possible alternativa al coure com a recobriment de la pantalla del feix de protons. En el marc d'aquesta tesi, hem caracteritzat les propietats elĂšctriques de diversos CC de REBCO disponibles comercialment, tant a DC com a corrents alterns d'alta freqĂŒĂšncia, en un ampli rang de temperatures criogĂšniques i sota camps magnĂštics de fins a 9T, on hem fet servir un ressonador dielĂšctric de tipus Hakki-Coleman amb una freqĂŒĂšncia de ressonĂ ncia de 8 GHz per a mesures d'impedĂ ncia superficial. ComplementĂ riament a aixĂČ, hem explorat la compatibilitat dels CC de REBCO amb els requisits de buit i qualitat de camp magnĂštic dins de la pantalla del feix del FCC, i hem desenvolupat una tĂšcnica de recobriment que permet cobrir a gran escala superfĂcies metĂ l·liques corbes, com ara la cĂ mera de la pantalla de feix, amb REBCO CC. Els resultats generats no nomĂ©s demostren que els CC de REBCO disponibles al mercat compleixen la promesa de mostrar propietats d'alta freqĂŒĂšncia excepcionalment bones sota les condicions de mesura, sinĂł que tambĂ© proporcionen solucions prĂ ctiques a problemes que abans dificultaven l'Ășs de REBCO a la cambra de la pantalla del feix o altres aplicacions de microones d'alt camp.Con el fin de impulsar la investigaciĂłn de la fĂsica de altas energĂas mĂĄs allĂĄ de la vida Ăștil del Gran Colisionador de Hadrones (LHC), la OrganizaciĂłn Europea para la InvestigaciĂłn Nuclear (CERN) iniciĂł una iniciativa de I + D para un colisionador de protones de 100 TeV con 100 km de circunferencia, el llamado Future Circular Collider (FCC). Parte del estudio del FCC es repensar el diseño de la pantalla del haz de protones, un componente del acelerador que alberga el haz de protones y protege tĂ©rmicamente los imanes superconductores de la radiaciĂłn de sincrotrĂłn. El concepto de la pantalla del haz de protones del LHC se basa en un tubo de acero inoxidable recubierto en su interior con cobre. Sin embargo, en las condiciones operativas previstas para el FCC, es decir, temperaturas de entre 40-60 K, bajo campos magnĂ©ticos de 16T y con corrientes inducidas en la pantalla del haz de 0-1 GHz, es posible que el recubrimiento de cobre no muestre una impedancia superficial lo suficientemente baja como para garantizar un haz de protones estable. La Ășnica clase de material conocida que presenta una menor resistencia superficial en determinadas condiciones, es la formada por superconductores. Desde enero de 2017, el grupo de Materiales Superconductores y Nanoestructuras a Gran Escala del Instituto de Ciencia de Materiales de Barcelona (ICMAB-CSIC) iniciĂł una colaboraciĂłn con el CERN para evaluar la idoneidad y optimizaciĂłn de las cintas superconductoras (CC, una estructura que consiste en una capa de material superconductor encima de un sustrato metĂĄlico flexible) de REBa2Cu3O7 (RE = tierras raras), como una posible alternativa al cobre como recubrimiento de la pantalla del haz de protones. En el marco de esta tesis, hemos caracterizado las propiedades elĂ©ctricas de varios CC de REBCO disponibles comercialmente, tanto en DC como en corrientes alternas de alta frecuencia, en un amplio rango de temperaturas criogĂ©nicas y bajo campos magnĂ©ticos de hasta 9T, donde hemos usado un resonador dielĂ©ctrico de tipo Hakki-Coleman con una frecuencia de resonancia de 8 GHz para medidas de impedancia superficial. Complementariamente a esto, hemos explorado la compatibilidad de los CC de REBCO con los requisitos de vacĂo y calidad de campo magnĂ©tico dentro de la pantalla del haz del FCC, y hemos desarrollamos una tĂ©cnica de recubrimiento que permite cubrir a gran escala superficies metĂĄlicas curvas, como la cĂĄmara de la pantalla de haz, con CC de REBCO. Los resultados generados no solo demuestran que los CC de REBCO disponibles en el mercado cumplen la promesa de mostrar propiedades de alta frecuencia excepcionalmente buenas bajo las condiciones de mediciĂłn, sino que tambiĂ©n proporcionan soluciones prĂĄcticas a problemas que antes dificultaban el uso de REBCO en la cĂĄmara de pantalla de haz u otras aplicaciones de microondas de alto campo.In order to drive high-energy research beyond the lifetime of the Large Hadron Collider (LHC), the European Organization for Nuclear Research (CERN) kicked off an R&D initiative for a 100 TeV proton-proton collider with 100 km circumference, the so-called Future Circular Collider (FCC). Part of the FCC study is to rethink the design of the beam screen, an accelerator component that houses the particle beam and thermally shields the cold bores of the steering magnets from the synchrotron radiation. The concept of the LHC beam screen is based on a stainless steel tube coated in its interior with copper. However, in the foreseen operating conditions of the FCC, i.e. 40-60 K, 16T and 0-1 GHz proton bunch frequency, the copper coating might not display a low enough surface impedance to guarantee a stable beam. The only known material class, which exhibits a lower surface resistance at given conditions, is formed by superconductors. Since January 2017, the Superconducting Materials and Large Scale Nanostructures group at the Material Science Institute in Barcelona (ICMAB-CSIC) started a collaboration with CERN to evaluate the suitability and optimization of REBa2Cu3O7 (RE = rare-earth) coated conductors (CCs), a structure consisting of a superconducting material layer on top of a flexible, metallic substrate, as a possible beam screen coating alternative to copper. In the framework of this thesis, we characterized the electrical properties of several commercially available REBCO CCs with both direct and high-frequency current excitation in a wide cryogenic range and at large magnetic fields up to 9T, where we employed a Hakki-Coleman type dielectric resonator with resonant frequency 8 GHz for surface impedance measurements. Complementary to this, we explored the compatibility of REBCO CCs with vacuum and field-quality requirements within the FCC beam screen and developed an attachment technique which enables the large-scale coating of curved, metallic surfaces, like the beam screen chamber, with REBCO CCs. Generated results not only demonstrate that commercially available REBCO CCs fulfill the promise of exceptionally good high-frequency properties at measurement conditions, but also propose practical solutions to issues which previously hindered the usage of REBCO in the beam screen chamber or other high-field microwave applications.Universitat AutĂČnoma de Barcelona. Programa de Doctorat en FĂsic
Gender and Identity Negotiation Through Talk-In-Interaction by Female Students of Computer and Systems Sciences
This study explores identity negotiation through talk-in-interaction by undergraduate female students at a male dominated study program of Computer and Systems Sciences at Stockholm University. The main aim of this study is to investigate what interactional identities are occupied by the female students in relation to Membership Categorisation Device âGenderâ. Theoretical framework that has been developed and used in this study is a combination of Grounded Theory and Membership Categorisation Analysis which is a part of Conversation Analysis developed by Harvey Sacks. The data has been collected through ten semi-structured interviews that have been conducted with undergraduate female students of Computer and Systems Sciences at Stockholm University. The results demonstrate that there are various ways in which the female students negotiate their interactional identity in relation to Membership Categorisation Device âGenderâ. The use of Membership Categorisation Device âGenderâ is both appropriated and rejected in negotiation of interactional identity. The results of this study might be useful in providing a better understanding of how interactional identity is negotiated by undergraduate female students of Computer and Systems Sciences at Stockholm University. In turn, that might facilitate effort of making gender ratio in male dominated IT-areas more equal. Moreover, the results of this study may contribute to further research on the relationship between gender identity negotiation by women in male dominated IT-areas and the phenomenon of âGender Paradoxâ
Priests' View on the Human Nature in Relation to Cyborgs
FoÌljande studie aÌmnar studera hur en grupp praÌster inom Svenska Kyrkan ser paÌ den maÌnskliga naturen i relation till cybernetiska organismer. Syftet med studien var att ta reda paÌ deras uppfattningar av graÌnsen mellan maÌnniska och maskin. Detta ansaÌgs vara viktigt eftersom deras syn paÌ maÌnniskans natur kan ge en djupare inblick i den paÌgaÌende debatten om maÌnsklig foÌrbaÌttring mellan forskare och religioÌsa foÌretraÌdare. Teorier som har anvaÌnts i studien aÌr transhumanism, biokonservatism, posthumanism samt Donna Haraways cyborgteori. FoÌr datainsamling har det genomfoÌrts fyra semi-strukturerade intervjuer med praÌster fraÌn olika foÌrsamlingar inom Svenska Kyrkan. Totalt har det identifierats fyra olika kategorier som har angetts utgoÌra den maÌnskliga naturen: âInnehav av en komplex inre vaÌrldâ; âKoppling till naÌgonting stoÌrre aÌn den fysiska/materiella verklighetenâ; âFoÌrfogande av en fri vilja inom en begraÌnsad ramâ samt âHaÌrkomst fraÌn âdet naturligaââ. Resultatet har visat att dessa kategorier har en rad olika relationer till cyborgkonceptet och maÌnsklig foÌrbaÌttring
Gender and Identity Negotiation Through Talk-In-Interaction by Female Students of Computer and Systems Sciences
This study explores identity negotiation through talk-in-interaction by undergraduate female students at a male dominated study program of Computer and Systems Sciences at Stockholm University. The main aim of this study is to investigate what interactional identities are occupied by the female students in relation to Membership Categorisation Device âGenderâ. Theoretical framework that has been developed and used in this study is a combination of Grounded Theory and Membership Categorisation Analysis which is a part of Conversation Analysis developed by Harvey Sacks. The data has been collected through ten semi-structured interviews that have been conducted with undergraduate female students of Computer and Systems Sciences at Stockholm University. The results demonstrate that there are various ways in which the female students negotiate their interactional identity in relation to Membership Categorisation Device âGenderâ. The use of Membership Categorisation Device âGenderâ is both appropriated and rejected in negotiation of interactional identity. The results of this study might be useful in providing a better understanding of how interactional identity is negotiated by undergraduate female students of Computer and Systems Sciences at Stockholm University. In turn, that might facilitate effort of making gender ratio in male dominated IT-areas more equal. Moreover, the results of this study may contribute to further research on the relationship between gender identity negotiation by women in male dominated IT-areas and the phenomenon of âGender Paradoxâ