Search Results

You are looking at 1 - 10 of 12 items for

  • Author or Editor: Endre Kiss x
  • All content x
Clear All Modify Search
Restricted access

In recent years there has been increasing research interest in the removal of nitrogen-oxides from exhaust gases using a pulsed corona discharge reactor. The pulsed streamer corona produces energetic electrons that excite, ionize and dissociate gas molecules, and by forming radicals that enhance the gas-phase chemical reactions which reduce the pollutant’s concentration.In this paper a method is presented, where the reaction rates of the electron-molecule collision are determined. The model is based on calculation of the energy of free electrons in the time and space varying field, considering the mean free path and the energy-dependent reaction cross sections of molecules. Knowing the rates, it is possible to solve the reaction kinetic equations, and to get the time-evolution of by-products, and the decomposition ratio of the pollutant gases.

Restricted access

As it is well known, the non-thermal plasma discharge is an effective way to clean the flue and exhaust gases of hazardous pollutants, like sulphur-oxides, nitrogen-oxides. The decomposition ratio of these substances depends on the gas composition, concentration, energy distribution of fast electrons, and other parameters. For a detailed analysis of the phenomena, the first step is the mathematical description of corona pulses which determines the electric field. The second step is the determination of the electric field distribution inside the reaction chamber.In this paper the authors give an easy model for the pulsed corona current and a simplified model for the electric field by using the corona current and the displacement current pulse shapes. The result of the model is the space and time dependent field distribution, which is suitable for calculating the rate coefficients of chemical reactions.

Restricted access

Abstract  

A typical 3-dimensional (in short '3D') Voronoi cell of a 3Dlattice has six families of parallel edges. We call any six representants of these six families the generating edges of the Voronoi cell. The sum s of lengths of generating edges of a Voronoi-cell of a lattice unit sphere packing in the 3-dimensional Euclidean space is a special case of intrinsic 1-volumes of 3Dzonotopes with inradius 1 which are investigated accurately in [B]. However, the minimum of this value is unknown even in this special case. As the regular rhombic dodecahedron shows optimal properties in many similar problems, it was reasonable to conjecture that it also has the minimal s value. In this note we present a construction of a lattice unit ball packing whose Voronoi cell possesses an intrinsic 1-volume strictly less than the one of the proper regular rhombic dodecahedron, hence providing a smaller upper bound for s than it was conjectured. A further issue of the note is a formula for edge-lengths of Voronoi cells of lattice unit ball packings that can be used efficiently in similar calculations.

Restricted access

In this paper the field distribution of different electrode arrangements and voltage supply systems has been investigated, and a new method has been developed to analyze them. The ozone production of the electrode arrangement has been investigated experimentally with the voltage supply system, and significant differences were found. The aim of this paper is to highlight the reasons for these differences in ozone production in relation to the potential and electric field distribution. For electrode arrangements the characteristics of the electric field, have been calculated by Finite Element Method completed with the Donor-Cell method for the space charge calculation. The index numbers related to the analysis of the field distribution and the ozone production have strong regression, which makes possible the estimation of the ozone production of the different arrangement.

Restricted access

Abstract  

In this note, first, we give a very short new proof of the theorem which yields a lower bound for the surface area of Voronoi cells of unit ball packings in E d and implies Rogers' upper bound for the density of unit ball packings in E d for all d ≥ 2. Second we sharpen locally a classical result of Gauss by finding the locally smallest surface area Voronoi cells of lattice unit ball packings in E 3.

Restricted access
Acta Geologica Hungarica
Authors: Tibor Zelenka, Endre Balázs, Kadosa Balogh, János Kiss, and at. al.

Surface Neogene volcanics in Hungary are abundantly documented in the literature, but buried volcanic structures are little known. Early burial of the volcanic centers beneath latest Miocene to Pliocene sediments preserved much of their original relief, permitting their classification into genetic types. More than two-thirds of Hungary is covered by thick Neogene and Quaternary sediments, below which buried volcanic eruptive centers and the extent of their products may only be recognized by complex geologic-geophysical methods. Our study is based on the data of several thousand wells, more than 60,000 km of seismic sections, as well as airborne and surface geophysical (gravimetric, magnetic, electromagnetic, radiometric) data. Results of chemical, mineralogical studies and K/Ar dating of deep cores were also included. The data were evaluated in terms of the regional deep structure of the Carpathian-Balkan region, the Miocene evolution of which was determined by the position, movement and welding of individual microplates. Integration of all available data reveals that the Miocene volcanic centers are concentrated near microplate boundaries. In the volcanic centers the lavas and pyroclastic deposits far exceed 50 m in thickness. The data show that the buried volcanic rocks below the Transdanubian region (Little Hungarian Plain and Somogy-Baranya Hills), the Danube-Tisza Interfluve and the Great Hungarian Plain extend over a much larger area than do the outcropping volcanoes in Northern Hungary (from the Visegrád to the Tokaj Mts). In the southern part of Transdanubia (W. Hungary) a major calcalkaline, rhyolitic, ignimbritic event took place early, in Eggenburgian and Ottnangian (Early Miocene) times. The centers and tuff sheets of this volcanic event can be traced from the Mecsek Mts to the Salgótarján Basin, the southwestern Bükk Basin and the central part of the Great Hungarian Plain. This event was followed by andesitic volcanism. The rhyolite and dacite volcanic centers of Karpatian age are predominantly situated in Transdanubia, whereas the Badenian (Mid-Miocene) andesite and dacite series of large stratovolcanoes are buried below southern Transdanubia, the Danube-Tisza Interfluve and the Great Hungarian Plain. In Sarmatian and early Pannonian (Late Miocene) times, pyroclastic sheets several thousand meters thick and lava domes were formed; they are predominantly rhyolitic, subordinately andesitic and dacitic, and are situated in the eastern part of the Great Hungarian Plain (Nyírség).  With the end of microplate motion, as the plate consolidated in the late Miocene, thick but areally restricted alkali-trachite (Little Hungarian Plain) and alkali-basalt lava domes and tuff craters formed in the Little Hungarian Plain, Transdanubia and the Danube-Tisza Interfluve.

Restricted access
Orvosi Hetilap
Authors: Balázs Németh, Péter Kustán, Ádám Németh, Zsófia Lenkey, Attila Cziráki, István Kiss, Endre Sulyok, and Zénó Ajtay

Absztrakt

A szív-ér rendszeri megbetegedések világszerte a leggyakrabban előforduló betegségek. Felelősek a globális halálozás egyharmadáért, vezető okai a rokkantságnak. A prevenció különböző szintjeinek hatékony kockázatbecsléssel együtt történő alkalmazása sokat javított a fent említett statisztikai adatokon. A klasszikus kockázati tényezőkön alapuló kockázatbecslés az utóbbi időben számos új markerrel egészült ki. Ilyen biomarker az aszimmetrikus dimetilarginin, amely a nitrogén-monoxid-szintáz endogén kompetitív inhibitora. Emelkedett szintjét leírták többek között elhízott, dohányos, hypercholesterinaemiás, hypertoniás, diabeteses betegcsoportokban. Irodalmi adatok szerint az aszimmetrikus dimetilarginin képes jelezni az atherosclerosis megelőző állapotának tartott endotheldiszfunkciót. Számos nagy betegszámú kutatás talált pozitív összefüggést a magasabb aszimmetrikus dimetilarginin koncentráció és a coronariabetegségek kialakulása, illetve a már meglévő coronariabetegség progressziója között. Egy 3000 fős beteganyagot vizsgáló tanulmány szerint az aszimmetrikus dimetilarginin független kockázati faktorként önmagában is képes előre jelezni a cardiovascularis okokból bekövetkező halálozást a coronariabetegségben szenvedők körében. Jelen írásukban a szerzők összefoglalják az aszimmetrikus dimetilarginin cardiovascularis betegségek előrejelzésében betöltött szerepét, és hangsúlyozzák kiemelt fontosságát a cardiovascularis prevencióban. Orv. Hetil., 2016, 157(13), 483–487.

Restricted access
Orvosi Hetilap
Authors: Zoltán Járai, Endre Kolossváry, Ildikó Szabó, István Kiss, Csaba Farsang, and Katalin Farkas

Absztrakt:

Bevezetés: A boka-kar index meghatározása során az oszcillometriás eszközök a hagyományos Doppler-elven működő eszközökkel összevetve több ígéretes előnyt mutatnak. A speciális képzés szükségtelensége, a gyorsabb kivitelezés, valamint a mérés operátortól független volta sorolható ezek közé. Célkitűzés: A boka-kar index oszcillometriás és a Doppler-elven működő meghatározásának összehasonlító elemzése. Módszer: A vizsgálati egyének esetében folyamatos hullámú Doppler és automata oszcillometriás (BOSO ABI-system 100) módszerrel a boka-kar index egyidejű meghatározását végeztük. Az összehasonlító elemzés Bland−Altman- és ROC-analízis alkalmazásával történt. Eredmények: A két módszerrel végzett vizsgálat (734 mérés) jó egyezést mutatott a boka-kar index tartomány 0,9 értékéhez közel. Ezen érték alatt és felett az egyezés mértéke csökkent. Az oszcillometriás mérés során optimálisnak tekinthető diagnosztikus boka-kar index határérték 0,96 volt. Következtetések: A boka-kar index oszcillometriás meghatározása nem helyettesíti a Doppler-alapú mérést a teljes boka-kar index tartományban. Mindazonáltal a hatékony diszkriminációs tulajdonságának köszönhetően a tünetmentes egyének szűrésekor hathatós eszköz lehet. Orv Hetil. 2018; 159(5): 176–182.

Restricted access