National Repository of Grey Literature 141 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Local referendum in the Czech republic
Vnoučková, Lucie ; Moravec, Marek (advisor) ; Čermák, Jiří (referee)
This bachelor's thesis deals with the topic of organizing and holding a local referendum in municipalities in Czech republic. The thesis is focused mainly on legal regulation of a local referendum in Czech republic and description of holding a local referendum. The practical part studies functioning of a local referendum in practice based on a research carried out by the Ministry of Interior
Administrative procedure of long-term residence permit for the purpose of study
Lašťovková, Karolina ; Moravec, Marek (advisor) ; Čermák, Jiří (referee)
(in English): This work aims to analyze and critically evaluate the legislation of long-term residence for the purpose of study. Formally, the work is divided into four chapters, which are then divided into individual subchapters. The first chapter presents the issue of the stay of foreigners, a brief outline of the historical development of the Aliens Act and legislation in this area. The second chapter contains the characteristics of administrative proceedings in general and explains the purpose of the study of long-term residence. In the third, main chapter, an analysis of administrative proceedings in the matter of long-term residence for the purpose of study for foreigners from third countries and related legislation is performed. The last, fourth chapter evaluates the provisions of the Commission for decision- making in matters of residence of foreigners and explains its meaning. Finally, the topic is summarized, subjectively evaluated and possible solutions to shortcomings are proposed.
PHASE COMPOSITION OF CHOSEN Mg-BASED MATERIALS DURING HYDROGEN SORPTION
Čermák, Jiří ; Král, Lubomír ; Roupcová, Pavla
Phase transformation during hydrogen sorption was investigated in ten chosen magnesium-based hydrogen storage (HS) materials. Chemical composition of the materials consisted of Mg, as a principal hydrogen-binding element, additive X and amorphous carbon (CB), as an anti-sticking component. In order to assess the effect of X itself upon the structure, values of concentration of both X and CB were fixed to about 12 wt. %. The influence of X = Mg2Si, Mg2Ge, Mg17Al12, Mg5Ga2, NaCl, LiCl, NaF, LiF and two combinations Ni+Mg17Al12 and Ni+Mg2Si upon the changes in phase composition was tested. Phase content in HS materials was observed (i) after the intensive ball milling (BM), (ii) after the BM followed by hydrogen charging at 623 K and (iii) after the BM and one hydrogen charging/discharging cycle (C/D) at temperature 623 K. The study was carried out by SEM and XRD. It was found that, the C/D is approximately structurally reversible for X = Mg2Ge, Mg17Al12, NaF and LiF. However, additives X = Mg17Al12 and NaF decompose already during the BM. In alloys with combination of Ni with Mg17Al12, new phases NimAln are formed. Phase composition changed during C/D for X = Mg2Si Mg5Ga2 and Ni+Mg2Si due to equilibration of phases composition. Observed structure changes of HS materials with chloride ionic additives NaCl and LiCl are, most likely caused by the relatively strong affinity between Mg and Cl. Hydrogen storage capacity of all studied alloys was 6.0 +/- 0.3 wt. % H-2.
HYDROGEN SORPTION IN ORDERED Mg-In ALLOYS
Čermák, Jiří ; Král, Lubomír ; Roupcová, Pavla
Hydrogen storage (HS) performance of three Mg- x In- y CB alloys (CB - amorphous carbon, x = 55, 64, 73 y =\n10 wt%) was studied. Indium concentration covered an area of ordered β structures. Alloys were prepared by\nball-milling in hydrogen atmosphere. Kinetic curves and PCT isotherms were measured in the temperature\ninterval from 200 °C to 325 °C. X-ray diffraction spectroscopy (XRD) was used for structure investigation. Alloy\nwith x = 73 wt% In ( β ’’ structure) showed reversible amorphization during temperature cycling between about\n100 °C and 350 °C. Hydrogen sorption experiments were done by the Sieverts method under the hydrogen\ngas pressure ranging from 0.1 MPa to 2.5 MPa. It was found that hydrogen sorption capacity varied between\n0.47 and 1.1 wt% H 2 . Hydride formation enthalpy ∆H calculated from desorption PCT experiments was\nsignificantly lower than ∆H , known for pure Mg. This invoked an idea that atomic order of Mg-based HS\nmaterials might decrease the high thermodynamic stability of hydride phase.
HYDROGEN STORAGE PROPERTIES OF GRAPHENE OXIDE MATERIALS PREPARED BY DIFFERENT WAYS
Král, Lubomír ; Čermák, Jiří ; Bytesnikova, Z.
Graphene-based materials show unique properties. These single layered materials consist of 2D structure of carbon atoms, belong to the strongest known materials, that are very mechanically flexible, optically transparent and that are excellent electrical and thermal conductors. Recently, several studies on these types of materials have highlighted the potential of this material for hydrogen storage (HS) and raised new hopes for the development of an effective solid-state HS media. In the present paper, the structure and HS properties of graphene oxide (GO) and chemically reduced graphene oxide (rGO) produced by different procedures were studied. Hydrogen sorption characteristics of GO and rGO were measured using the Sieverts-type gas sorption analyzer PCT-Pro Setaram Instrumentation. The study of HS was carried out at temperature range from 198 K to 423 K under hydrogen pressure from 1x10(-4) to 4 MPa. \n\nFor the HS point of view, the advantage of GO or rGO compared to graphene, is the presence of multiple chemical groups that can be used for introducing modifiers and their superior spreading on the materials surface. The suitably functionalized GO or rGO materials could potentially exhibit outstanding HS properties.
HYDROGEN STORAGE PROPERTIES OF GRAPHENE OXIDE MATERIALS PREPARED BY DIFFERENT WAYS
Král, Lubomír ; Čermák, Jiří ; Bytesnikova, Z.
Graphene-based materials show unique properties. These single layered materials consist of 2D structure of carbon atoms, belong to the strongest known materials, that are very mechanically flexible, optically transparent and that are excellent electrical and thermal conductors. Recently, several studies on these types of materials have highlighted the potential of this material for hydrogen storage (HS) and raised new hopes for the development of an effective solid-state HS media. In the present paper, the structure and HS properties of graphene oxide (GO) and chemically reduced graphene oxide (rGO) produced by different procedures were studied. Hydrogen sorption characteristics of GO and rGO were measured using the Sieverts-type gas sorption analyzer PCT-Pro Setaram Instrumentation. The study of HS was carried out at temperature range from 198 K to 423 K under hydrogen pressure from 1x10(-4) to 4 MPa.
INFLUENCE OF GRAPHITE UPON THE KINETICS OF HYDROGEN SORPTION IN Mg@Mg17Al12
Čermák, Jiří ; Král, Lubomír ; Roupcová, Pavla
Influence of graphite addition to the ball-milling charge composed of Mg splinters and Mg17Al12 particles upon the hydrogen sorption was investigated at sorption temperature 623 K. Measurements were carried out by Sieverts method. Graphite facilitates the ball-milling: It prevents re-agglomeration of crushed particles into large secondary particles. It also suppresses sticking the milled material to the balls and walls of the milling jar. It was found that an increase of carbon concentration up to a certain limit c(L) lying between 14 and 23 wt. % C, carbon increases both the absorption and the desorption rates and hydrogen storage capacity. Above c(L), carbon causes a considerable decrease in HS capacity, which spoils the application potential of Mg@Mg17Al12/C. Crystallite size of the material under study, obtained by XRD, is in the order of tens of nm.
ESTIMATION OF EQUILIBRIUM HYDROGEN PRESSURE - A NEW METHOD
Čermák, Jiří ; Král, Lubomír
A new method is proposed to estimation of hydrogen pressure in equilibrium with hydride phase in a hydrogen\nstorage material. It is applicable both for hydrogen absorption and desorption in cases where the hydride phase\nis formed by nucleation and growth mechanism. The proposed method saves considerably the experimental\ntime replacing the conventional time consuming measurement of pressure-composition isotherms, the so\ncalled PCT curves. The proposed evaluation procedure is illustrated using hydrogen chemi-sorption at\ntemperatures 623 K, 573 K and 523 K in chosen hydrogen storage alloys Mg-Si-C, Mg-Li-C and Mg-Na-C.
Estimation of equilibrium hydrogen pressure - A new method
Čermák, Jiří ; Král, Lubomír
A new method is proposed to estimation of hydrogen pressure in equilibrium with hydride phase in a hydrogen\nstorage material. It is applicable both for hydrogen absorption and desorption in cases where the hydride phase\nis formed by nucleation and growth mechanism. The proposed method saves considerably the experimental\ntime replacing the conventional time consuming measurement of pressure-composition isotherms, the so\ncalled PCT curves. The proposed evaluation procedure is illustrated using hydrogen chemi-sorption at\ntemperatures 623 K, 573 K and 523 K in chosen hydrogen storage alloys Mg-Si-C, Mg-Li-C and Mg-Na-C.
HYDROGEN SORPTION BEHAVIOR OF CHOSEN BINARY MAGNESIUM-CONTAINING INTERMETALLICS
Čermák, Jiří ; Král, Lubomír ; Roupcová, Pavla
Hydrogen absorption in chosen binary Mg-X (X-Al, Ga, In, Si and Sn) intermetallics was studied. These compounds are prospective as additives in other Mg-based hydrogen storage materials. From this point of view it is desirable to know the hydrogen solubility in Mg-X and their resistivity against hydride formation. The present study was carried out at temperatures up to 623 K.

National Repository of Grey Literature : 141 records found   1 - 10nextend  jump to record:
See also: similar author names
12 ČERMÁK, Jakub
85 ČERMÁK, Jan
5 ČERMÁK, Jaromír
65 ČERMÁK, Jiří
1 Čermák, J.
12 Čermák, Jakub
85 Čermák, Jan
5 Čermák, Jaromír
10 Čermák, Jaroslav
1 Čermák, Josef
2 Čermák, Justin
Interested in being notified about new results for this query?
Subscribe to the RSS feed.