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Preliminary Measurements of Neutrons From The D-D Reaction in The Compass Tokamak
Dankowski, J.; Janky, Filip; Kurowski, A.; Stöckel, Jan; Twarog, D.
2014 - anglický
Recent results of measured fast neutrons created in the D-D reaction on the COMPASS tokamak during ohmic discharges are presented in this paper. Two different type detectors were used during experiment. He-3 detectors and bubble detectors as a support. The measurements are an introduction for neutron diagnostic on tokamak COMPASS and monitoring neutrons during discharges with Neutral Beam Injection (NBI). The He-3 counters and bubble detectors were located in two positions near tokamak vacuum chamber at a distance less than 40 cm to the centre of plasma. The neutrons flux was observed in ohmic discharges. However, analysis of our results does not indicate any clear source of neutrons production during ohmic discharges.
Klíčová slova:
fusion; tokamak; neutrons; plasma diagnostics; COMPASS; bubble detectors
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Preliminary Measurements of Neutrons From The D-D Reaction in The Compass Tokamak
Recent results of measured fast neutrons created in the D-D reaction on the COMPASS tokamak during ohmic discharges are presented in this paper. Two different type detectors were used during ...
Poisson Equation Solver Parallelisation for Particle-in-Cell Model
Podolník, Aleš; Komm, Michael; Dejarnac, Renaud; Gunn, J. P.
2014 - anglický
Numerical simulations based on PIC technique like the SPICE2 model developed at IPP ASCR are often used in tokamak plasma physics to investigate the interaction of edge plasma with plasma-facing components. The SPICE2 model has been parallelised with the exception of the Poisson equation solver which considerably slows down the simulations. It is now being upgraded to a parallelised version to be efficient enough to perform more demanding tasks like the ITER tokamak baseline scenario edge plasma whose conditions like high density (up to 1020 m−3) and low temperature (1–2 eV) result in simulations taking several months to compute. Performance and scaling are compared for different cases in order to choose the optimal candidate for aforementioned applications.
Klíčová slova:
plasma; tokamak; ITER
Dokument je dostupný na externích webových stránkách.
Poisson Equation Solver Parallelisation for Particle-in-Cell Model
Numerical simulations based on PIC technique like the SPICE2 model developed at IPP ASCR are often used in tokamak plasma physics to investigate the interaction of edge plasma with plasma-facing ...
Influence of isothermal exposure on microstructural changes resulting in delamination of eutectic Al2O3+ZrO2+SiO2 thermal barrier coatings
Jech, D.; Čelko, L.; Chráska, Tomáš; Slámečka, K.; Klakurková, L.; Dubský, Jiří; Švejcar, J.
2014 - anglický
Eutectic ceramic Al2O3-ZrO2-SiO2 also termed Eucor (as a top coat) and CoNiCrAlY (as a bond coat) coatings were sprayed onto the surface of recently developed fine-grained cast polycrystalline nickel-based superalloy Inconel 713 LC by means of water stabilized plasma (WSP) and atmospheric plasma spraying (APS) techniques, respectively.Specimens were subjected to isothermal oxidation at 1050 °C for 10, 50, 100, 200 and 500 hours in ambient atmosphere,prior to which a half of the as-sprayed specimens was annealed at the temperature of 950 °C for 10 hours.Influence of short-time and long-time isothermal exposure on interactions at the bond-coat/top-coat interface was studied.The uniform and continuous oxide layer,also termed the thermally grown oxide (TGO),was formed and grew at the bond-coat/top-coat interface in all samples, both with and without the heat pre-treatment. Relationship between the dwell time, heat treatment and TGO growth kinetics was quantified.Microstructural changes
Klíčová slova:
Electron microscopy-scanning; Heat treatment; Image analysis; Thermal barrier coatings; Thermal plasma spraying
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Influence of isothermal exposure on microstructural changes resulting in delamination of eutectic Al2O3+ZrO2+SiO2 thermal barrier coatings
Eutectic ceramic Al2O3-ZrO2-SiO2 also termed Eucor (as a top coat) and CoNiCrAlY (as a bond coat) coatings were sprayed onto the surface of recently developed fine-grained cast polycrystalline ...
Thermal Coatings for Glass Industry
Chráska, Pavel; Neufuss, Karel
2014 - anglický
A new type of plasma torch with combined stabilization of electric arc by water vortex and gas flow is presented. This hybrid water/gas stabilization offers the possibility of adjusting plasma jet parameters within a wide range from high-enthalpy low-density plasmas typical for liquid stabilized torches to lower enthalpy higher density plasmas generated in gas stabilized torches. Moreover, gas flow in the cathode part protects a cathode tip and thus a consumable graphite cathode used in water-only stabilized plasma torches could be replaced by a fixed tungsten cathode. Examples of hybrid WSP torch utilization for high temperature application are given.
Klíčová slova:
glass melts; high temperature loading; glass forming tools; service life; coatings
Dokument je dostupný na externích webových stránkách.
Thermal Coatings for Glass Industry
A new type of plasma torch with combined stabilization of electric arc by water vortex and gas flow is presented. This hybrid water/gas stabilization offers the possibility of adjusting plasma jet ...
Klimatické změny - aktuality do roku 2012
Oupický, Pavel
2014 - český
V článku je uveden přehled o klimatických změnách aktuálně do roku 2012 There is reported in this paper about climate changes in the year 2012
Klíčová slova:
Global warming; Typhoons; Glaciation; plants; aerosols; flooding
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Klimatické změny - aktuality do roku 2012
V článku je uveden přehled o klimatických změnách aktuálně do roku 2012
There is reported in this paper about climate changes in the year 2012
Composites of titanium carbide with scandium matrix
Brožek, Vlastimil; Pala, Zdeněk; Vilémová, Monika; Kubatík, Tomáš František; Mušálek, Radek; Nevrlá, Barbara; Mastný, L.
2014 - anglický
First reference about existence of ultrahard composite in the TiC-ScCx system was made by G.V. Samsonov in the year 1962. Further research performed on ICT Prague and University of Vienna proved a discrepancy in the structure and stoichiometry of scandium carbide. Analogously to cubic carbides and nitrides of 3rd period metals, Scandium was also expected to have extreme hardness, high chemical stability and to enable solid solution formation (Vegard rule) with controlled regulation of physical parameters. Higher hardness of the cubic carbides is related to the decrease of lattice parameter, thus is was expected that smaller atomic radius of Sc in TixSc1-xC solid solution will lead to increase in hardness. However it was discovered that scandium carbide differs chemically as well as structurally, e.g. Sc15C19 is hydrolyzed and the product of the reaction is hydrogen, allylen and other hydrocarbons. Due to high price of Sc compounds, CVD and PVD layers of TiAlN or TiScAlN on sintered
Klíčová slova:
hard compounds; titanium carbide; scandium oxycarbide; spark plasma sintering
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Composites of titanium carbide with scandium matrix
First reference about existence of ultrahard composite in the TiC-ScCx system was made by G.V. Samsonov in the year 1962. Further research performed on ICT Prague and University of Vienna proved a ...
Selective Leaching as a Method of Metallic Nanoparticles Preparation
Michalcová, A.; Vojtěch, D.; Kubatík, Tomáš František; Marek, I.; Svobodová, P.; Novák, P.
2014 - anglický
Selective leaching is process used mainly in analytical praxis–alloy matrix is dissolved and the residuum can be study by different methods. In this article, modification of selective leaching determined for production of metallic nanoparticles is described.Selective leaching technique lays in preparation of supersaturated solid solution of desired element in matrix metal –by convenient heat treatment or by rapid solidification of the binary alloy. Consequently, the matrix metal is selectively dissolved and metal nanoparticles from other metal are formed. The size, shape and agglomeration of forming metallic nanoparticles are dependent on many factors such as reaction temperature, concentration of leaching solution, additives present in leaching solution. The metal mainly used as matrix component is aluminium due to is amphoteric behaviour. It enables aluminium dissolution in sodium hydroxide without affecting the minor metal. Nobel metals like silver or copper forms
Klíčová slova:
Nanocrystaline materials; selective leaching
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Selective Leaching as a Method of Metallic Nanoparticles Preparation
Selective leaching is process used mainly in analytical praxis–alloy matrix is dissolved and the residuum can be study by different methods. In this article, modification of selective leaching ...
Netradiční techniky studia porušování materiálů zpracovaných plazmovou technologií
Mušálek, Radek
2014 - český
V příspěvku je uvedeno několik příkladů použití vybraných netradičních metod pro studium porušování materiálů připravených plazmovou technologií - plazmovým stříkáním a slinováním v pulzním elektrickém poli (Spark Plasma Sintering – SPS). Tyto materiály mají mikrostrukturu, která se zásadně liší od struktury konvenčních materiálů a možnosti použití klasických metod studia porušování jsou značně omezené. Například také proto, že často není k dispozici dostatečný objem materiálu. Cílem příspěvku je ilustrovat výhody propojení studia změn mikrostruktury během zatěžování a makroskopických vlastností zkoumaných materiálů. This paper presents examples of several methods, which may be used for failure study of materials prepared by plasma processing - plasma spraying or plasma sintering. Microstructure of these materials significantly differs from that of bulk construction materials which limits use of conventional methods. Typically, because not enough volume of material in one piece is available for testing. Aim of this paper is to ilustrate benefits of using combined study of materials changes during loading and their macroscopic properties
Klíčová slova:
plasma-processed materials; failure; micromechanisms
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Netradiční techniky studia porušování materiálů zpracovaných plazmovou technologií
V příspěvku je uvedeno několik příkladů použití vybraných netradičních metod pro studium porušování materiálů připravených plazmovou technologií - plazmovým stříkáním a slinováním v pulzním ...
THERMAL AND MECHANICAL PROPERTIES OF TUNGSTEN COMPACTS PREPARED BY SPS
Nevrlá, Barbara; Vilémová, Monika; Matějíček, Jiří
2014 - anglický
Tungsten is a promising candidate material for use in the tokamak device aimed at future production of nuclear fusion power. Here, tungsten is intended for the application in the part called first wall,with the function of a heat-resistant plasma facing armor.In the present work,two fractions of tungsten powder (2 and 4 μm) were used to prepare two consolidated samples by spark plasma sintering (SPS),using a combination of pressure,temperature and electric power.This sintering technique produces samples of near theoretical density which is positive for the application.Tungsten compacts were then studied to determine some basic thermal and mechanical properties, namely thermal conductivity using the laser-flash method and hardness by Vickers test.The measurements were focused on thermal conductivity of the compacts because high thermal conductivity is crucial for the material of tokamak first wall,loaded by high heat flux from the plasma.High hardness is desirable for good resistance
Klíčová slova:
spark plasma sintering; tungsten; thermal properties
Dokument je dostupný na externích webových stránkách.
THERMAL AND MECHANICAL PROPERTIES OF TUNGSTEN COMPACTS PREPARED BY SPS
Tungsten is a promising candidate material for use in the tokamak device aimed at future production of nuclear fusion power. Here, tungsten is intended for the application in the part called first ...
Global Power Balance in Non-Stationary Discharge Phases in the COMPASS Tokamak
Havlíček, Josef; Imríšek, Martin; Kovařík, Karel; Weinzettl, Vladimír
2014 - anglický
The global power balance between different input power and sink/loss channels is important for understanding of tokamak physics, particularly for various scaling laws. The power balance is measured easily during stationary discharge phases because the terms for both magnetic field energy and plasma thermal energy build-up can be neglected. However, many important events in tokamak plasmas occur during non-stationary phases of the discharge. This article describes, quantifies and discusses the terms of the global power balance, including time dependent parts, and exemplifies them on the typical ohmic discharge of the COMPASS tokamak.
Klíčová slova:
tokamak; global power balance; power through separatrix; COMPASS
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Global Power Balance in Non-Stationary Discharge Phases in the COMPASS Tokamak
The global power balance between different input power and sink/loss channels is important for understanding of tokamak physics, particularly for various scaling laws. The power balance is measured ...
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