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FITTING OF ELASTIC MODULUS ON THE INTERFACE BETWEEN TWO MATERIALS
Kocmanová, Lenka; Materna, A.; Haušild, P.; Matějíček, Jiří
2014 - Czech
The paper is aimed to determinate of Young modulus near a sharp interface. The 3D elastic numeric model was used for prediction of the Young modulus. The simulated specimen was composed of tungsten and steel. The interface was plane which a normal vector was perpendicular to the indentation force. The indenter geometry for which numerical solutions were accomplished was a rounded cone indenter. An indentation depth is studied as function of a distance indenter-interface. The distance was normalized by depth of indentation. All values of Young modulus lay on one curve after distance normalization due to elasticity. The curve was fitted by inverse beta function. The curve determine the size of area of one material influenced by a second material. Příspěvek je zaměřený na určování elastického modulu pružnosti na ostrém rozhraní mezi dvěma materiály. K určení elastického modulu pružnosti byl použit 3D numerický model nanoindentace s kuželovým indentorem. Nasimulovaný vzorek byl vytvořený z wolframu a oceli. Rozhraní je rovina s normálou kolmou ke směru vtisku. Je studován vliv vzdálenosti od rozhraní a hloubky vtisku. Dále byla vzdálenost od rozhraní normována hloubkou vtisku. Geometrická podobnost vtisků zapříčinila, že hodnoty elastického modulu pružnosti v závislosti na normované vzdálenost od rozhraní leží na jedné křivce. Tato křivka byla fitována beta funkcí a inverzní beta funkcí metodou nejmenších čtverců a beta funkcí vypočítanou jako nejmenší rozdíl ploch pod křivkou. Nejvhodnější pro fitování rozhraní byla inverzní beta funkce. Díky fitování bylo možné určit velikost oblasti ovlivněné druhou fází.
Keywords:
Nanoindentation; finite element method; material interface
Available at various institutes of the ASCR
FITTING OF ELASTIC MODULUS ON THE INTERFACE BETWEEN TWO MATERIALS
The paper is aimed to determinate of Young modulus near a sharp interface. The 3D elastic numeric model was used for prediction of the Young modulus. The simulated specimen was composed of tungsten ...
Simulation of Residual Optical Aberrations of Objective Lens 210/3452 of Solar Spectrograph of Ondřejov Observatory
Rail, Zdeněk; Jareš, Daniel; Melich, Radek
2014 - Czech
At the end of 2012 was done measuring and clean the lens 210/3452 of the solar spectrograph Observatory Astronomical Institute Academy of Sciences in Ondrejov. The spectrograph is working in line H-alpha and is formed by a birefringent lens-polarizing filter, positioned in front of the focal plane. The measured values are enumerated in the optical properties. In a report to present to the results of mathematical quantification of residual defects and new optical system design suitable for use Fabry-Perot filters. Koncem roku 2012 bylo provedeno přeměření a vyčištění objektivu 210/3452 slunečního spektrografu observatoře AsÚ AVČR v Ondřejově. Spektrograf pracuje v čáře H-Alfa a je tvořen tímto objektivem a dvojlomně-polarizačním filtrem, umístěným před jeho ohniskovou plochou. Z naměřených hodnot jsme vyčíslili jeho optické vlastnosti. V referátu předkládáme jak výsledky matematického vyčíslení zbytkových vad, tak nové optické návrhy systémů vhodných pro použití filtrů Fabry-Perota.
Keywords:
Optical design of solar spectrograph; chromospheric observation; measurement of parameters of dublet lens; evaluation of residual optical aberrations; stigmatic imaging; narrow-band Šolc birefringent filter; Fabry-Perot filter; Day-Star filter; Ondrejov observatory
Available at various institutes of the ASCR
Simulation of Residual Optical Aberrations of Objective Lens 210/3452 of Solar Spectrograph of Ondřejov Observatory
At the end of 2012 was done measuring and clean the lens 210/3452 of the solar spectrograph Observatory Astronomical Institute Academy of Sciences in Ondrejov. The spectrograph is working in line ...
Plasmachemical reactors for special syntheses and decomposition
Brožek, Vlastimil; Janča, J.; Mastný, L.
2013 - Czech
In the contribution the design of laboratory plasmachemical reactors for performing chemical reactions with high activation energy is described. It concerns RF-reactors with the capacity or induction excitation of the plasma, plasmachemical reactor with the unipolar microwave discharge, low-frequency gliding plasma reactor (Glid-Arc), and particularly the high-performance generator with water stabilized plasma of Czech provenience WSP®. Operation, effectiveness and output of these reactors are demonstrated on the syntheses of boron carbide and boron nitride of both solid and gaseous precursors, on the syntheses of inorganic pigments on the basis of zirconia, fluorite or condensed polyphosphates and also on tungsten carbide. All of them can be prepared in nanometric particle size with high specific surface area (tens of m2/g). V příspěvku jsou popsány konstrukce laboratorních a poloprovozních plazmochemických reaktorů, ve kterých mohou probíhat chemické reakce s vysokou hodnotou aktivační energie. Jedná se o RF-reaktory s kapacitním nebo indukčním buzením plazmatu, dále o plazmochemické reaktory s jednopólovým mikrovlnným výbojem, nízkofrekvenční plazmové reaktory s klouzavým výbojem (Glid-Arc) a zejména o vysoce výkonný generátor vodou stabilizovaného plazmatu české provenience, WSP®. Funkce, účinnost a efektivnost reaktorů je dokumentována na příkladech syntézy karbidu boru a nitridu boru z pevných i plynných prekurzorů, na syntéze anorganických pigmentů na bázi zirkonu, fluoritu nebo kondenzovaných polyfosfátových pigmentů a dále karbidu wolframu, které lze připravit v nanometrické granulometrii s vysokým měrným povrchem (desítky m2/g).
Keywords:
Plasmachemical reactors; plasma generator WSP; RF-plasma; MW-plasma; Glid-Arc; nanoparticle syntheses
Available at various institutes of the ASCR
Plasmachemical reactors for special syntheses and decomposition
In the contribution the design of laboratory plasmachemical reactors for performing chemical reactions with high activation energy is described. It concerns RF-reactors with the capacity or induction ...
Preparation of quasicrystals Al-Cu-Fe by mechanical alloying and SPS
Novák, P.; Kubatík, Tomáš František; Hendrych, R.; Voděrová, M.; Vojtěch, D.
2013 - Czech
This work deals with the preparation of fine-grained material based on quasicrystalline phase of Al-Fe-Cu powder metallurgy using mechanical alloying and compaction method "Spark Plasma Sintering". Described the dependence of the microstructure and phase composition of powders depending on the conditions of the mechanical alloying. It was studied the stability of the quasicrystalline phase at various temperatures and times of compacting Tato práce se zabývá přípravou jemnozrnného materiálu na bázi kvazikrystalické fáze Al-Fe-Cu technologií práškové metalurgie využívající mechanického legování a kompaktizace metodou „Spark Plasma Sintering“. Byla popsána závislost mikrostruktury a fázového složení prášků v závislosti na podmínkách mechanického legování. Byla studována stabilita kvazikrystalické fáze při různých teplotách a dobách kompaktizace.
Keywords:
Quasicrystals; mechanical alloying; Spark Plasma Sintering
Available at various institutes of the ASCR
Preparation of quasicrystals Al-Cu-Fe by mechanical alloying and SPS
This work deals with the preparation of fine-grained material based on quasicrystalline phase of Al-Fe-Cu powder metallurgy using mechanical alloying and compaction method "Spark Plasma Sintering". ...
Planar acoustic metamaterials with the active control of acoustic impedance using a piezoelectric composite actuator
Nováková, Kateřina; Mokrý, P.; Václavík, J.; Marton, P.; Cernik, M.; Psota, Pavel; Doleček, Roman; Lédl, Vít
2013 - English
In the Paper, there are presented methods for a precise active control of the acoustic impedance of large planar structures, e.g glass plates or shells, by means of distributed flexible piezoelectric composite actuators which are connected to passive or active electronic shunt circuits. Design of tunable acoustic metamaterials is realized using Finite Element Method simulations and their acoustic properties are evaluated using acoustic transmission loss measurements. Static and dynamic displacements of the metamaterials produced by electric voltage are measured using Digital Holographic Interferometry. We believe that deep understanding of presented systems should result in future applications that improve the quality of everyday life.
Keywords:
Planar acoustic metamaterials; Active control of acoustic impedance; Piezoelectric composite actuator
Available at various institutes of the ASCR
Planar acoustic metamaterials with the active control of acoustic impedance using a piezoelectric composite actuator
In the Paper, there are presented methods for a precise active control of the acoustic impedance of large planar structures, e.g glass plates or shells, by means of distributed flexible piezoelectric ...
Reactor for the preparation of nanoparticles in plasma discharge
Brožek, Vlastimil; Benešová, L.; Mastný, L.; Sýkora, V.
2013 - Czech
New variety of a plasmachemical reactor for the preparation of nanoparticles from liquid or aerosol precursors in which liquid precursors were brought into the current of plasma in the places where the temperature reached 4000K–5000K was reconstructed. As a generator of plasma was used the plasma torch WSP® which was developed and patented by IPP AS CR. We worked on liquid precursors which were H[AuCl4],AgNO3 and H2[PtCl6],that decomposed in the high temperature environment and so colloidal solutions of metallic nanoparticles of gold, silver and platinum were emerged in concentration of 5mg/l–50mg/l with the size of particles 25nm–100nm depending on the starting point of the precursor concentration. Further experiments for preparation so-called double oxides served us as a check of universality of this method but also its wide adaptability.That was the preparation of spinel MgAl2O4 and ferrite CoFe2O4 from the sulfate solutions.By the horizontal device arrangement it is possible to Pro přípravu nanočástic z kapalných nebo aerosolových prekurzorů byla zkonstruována nová varianta rozprašovacího plazmového reaktoru (liquid flame spray reactor),ve kterém byly kapalné prekurzory vnášeny do proudu vodou stabilizovaného plazmatu z generátoru WSP® v místech,kde teplota dosahovala 4000K–5000K.Kapalné prekurzory - roztoky H[AuCl4],AgNO3 a H2[PtCl6]-se v prostředí nízkoteplotního plazmatu rozkládaly a vznikaly sférické kovové nanočástice s velikostí 25nm-100nm v závislosti na výchozí koncentraci roztoku. K ověření univerzálnosti metody a její široké adaptability posloužily experimenty přípravy podvojných oxidů, spinelu MgAl2O4 a feritu CoFe2O4 ze síranových nebo dusičnanových roztoků.Po zachycení v kapalinovém separátoru byly získány koloidní roztoky kovů nebo oxidů o koncentraci 5-50mg/l.Aparatura umožňuje funkci jak ve vertikálním, tak i horizontálním uspořádání.Při horizontálním uspořádání je možno vytvářet nanostrukturované povlaky na vybraných substrátech.
Keywords:
water stabilized plasma; plasmachemical reactor; plasma spraying; nanoparticles formation; nanostructured coatings
Available at various institutes of the ASCR
Reactor for the preparation of nanoparticles in plasma discharge
New variety of a plasmachemical reactor for the preparation of nanoparticles from liquid or aerosol precursors in which liquid precursors were brought into the current of plasma in the places where ...
Thermal spraying of suspensions and solutions
Mušálek, Radek
2013 - Czech
Recently beginning to be selected for some applications of thermal spraying interesting administration of nanometric or micrometric powders in suspension, or preparation of particles from a solution directly over zinc deposition. This paper provides basic information about this new route of administration and its benefits for technical practice. V poslední době začíná být pro některé vybrané aplikace žárového stříkání zajímavé podávání nanometrických či mikrometrických prášků ve formě suspenze, případně příprava částic z roztoku přímo během žárové depozice. Tento příspěvek podává základní informaci o tomto novém způsobu podávání a jeho výhodách pro technickou praxi.
Keywords:
thermal spraying; suspensions; solutions
Available at various institutes of the ASCR
Thermal spraying of suspensions and solutions
Recently beginning to be selected for some applications of thermal spraying interesting administration of nanometric or micrometric powders in suspension, or preparation of particles from a solution ...
Possibilities of welding observation with regard of sielding gas
Rohan, P.; Vojtíšek, Petr
2013 - English
MAG welding is characterized by very rapid processes in extreme condition of electric arc. To describe welding is necessary to use sufficiently quick equipment. Especially in the transition region between dip and spray transfer the processes develop quickly. Characterization of transition area in active three component shielding gas was carried out visually by hi speed camera equipment and electrically by quick response electronic measurement system.
Keywords:
Welding; direct observation; welding gas
Available at various institutes of the ASCR
Possibilities of welding observation with regard of sielding gas
MAG welding is characterized by very rapid processes in extreme condition of electric arc. To describe welding is necessary to use sufficiently quick equipment. Especially in the transition region ...
Tungsten coatings and free standing parts
Brožek, Vlastimil; Ctibor, Pavel; Matějíček, Jiří; Mušálek, Radek; Weiss, Z.
2013 - English
Tungsten powders, 20 – 100 µm in size, were melted in the jet of thermal plasma generated by a water-stabilized spray system WSP®. The molten tungsten was deposited on steel and graphite or boron nitride substrates, whereas the spray-ability itself was tested as well as cohesion with other substrates. One of the goals of this experimentation was to gain skills for covering variously shaped walls of nuclear fusion devices (Tokamaks). Also spraying of free-standing tungsten bodies was realized, by means of substrates easily machainable-out after deposition, as graphite and BN. Other option consists of covering a tungsten mesh or plates armored with tungsten wires. Protection of tungsten against oxidation in the plasma jet was a problem to be solved – the best results were gained with shroud gas, Ar with 7% hydrogen, and simultaneous placement of the substrates into graphite cells. The whole spray process was maintained to avoid temperatures over 700°C at which the oxidation is
Keywords:
tungsten coatings; tungsten filters; plasma spraying; shrouding; tungsten plasma spraying; protection against oxidation
Available at various institutes of the ASCR
Tungsten coatings and free standing parts
Tungsten powders, 20 – 100 µm in size, were melted in the jet of thermal plasma generated by a water-stabilized spray system WSP®. The molten tungsten was deposited on steel and graphite or boron ...
Preparation of gold, silver and platinum colloid solutions by precursors decomposition in low temperature plasma
Brožek, Vlastimil; Kutílek, Zdeněk; Mastný, L.; Sýkora, V.; Benešová, L.; Sofer, Z.
2013 - English
Liquid precursor decomposition in the low temperature plasma generated by WSP® was used for synthesis of precious metals nanoparticles. The gold in the form of H[AuCl4], silver in the form of AgNO3 and platinum in the form of H2[PtCl6] were used to generate colloid solutions with concentration of 5 mg.l-1 – 70 mg.l-1 and particle size of 20 nm – 120 nm. The solution contained elevated concentration of nitrite and nitrate ions due to the reaction of plasma with nitrogen form air. In order to reduce the concentration of nitrite and nitrate ions the plasma generated nanoparticles was projected by plasma torch to the ammonium chloride solution. Other way used for reduction of NO3- and NO2- concentration was optimization of geometry of plasma system. The other way was also by application of shrouding effect by nitrogen and ammonia gas. The size of nanoparticles and their concentration can be influenced by geometry of plasma torch, composition of carrier gas and by geometry of
Keywords:
colloidal suspension; gold nanoparticles; silver nanoparticles; platinum nanoparticles; plasma generator; low temperature plasma
Available at various institutes of the ASCR
Preparation of gold, silver and platinum colloid solutions by precursors decomposition in low temperature plasma
Liquid precursor decomposition in the low temperature plasma generated by WSP® was used for synthesis of precious metals nanoparticles. The gold in the form of H[AuCl4], silver in the form of AgNO3 ...
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