The diatom flora and vegetation of Lake Balaton from sediment cores according to Márta Hajós's legacy

The diatoms of bottom sediment core samples were studied from Lake Balaton. During the 1980s altogether 33 boreholes were drilled into the Quaternary layers down to 10-12 m. This paper presents the diatom flora and vegetation of 17 boreholes based on the legacy of Márta Hajós who spent 16 years working on this subject. The enumeration contains occurrences of 385 diatom taxa. It is hoped that this scientific account will serve as a “diatom databank” and helps better understanding of recent environmental changes in the larger area. Kulcsszavak Hungary, Hungary, Lake Balaton, diatoms, palaeolimnology, shallow lake

A coupled geothermal model of the Alpokalja area, Hungary—Austria

A coupled groundwater flow and heat transport model was developed for a trans-boundary geothermal reservoir located in the Alpokalja area. The study area lies in the western part of the Pannonian Basin, at the border between Hungary and Austria. The study area contains several famous geothermal water utilizations on both sides of the border, which has an impact on natural groundwater conditions. The aim of the modeling study was to evaluate the natural-state and production-state groundwater conditions, and to make predictions on cross-boundary interferences. A three-dimensional finite element-type coupled geothermal model was constructed to provide a coherent quantitative representation of geothermal flow systems. The model described the hydraulic behavior of the flow system, the interaction between different reservoirs, and geothermal conditions

Distribution and composition of Mg-calcite and dolomite in the water and sediments of Lake Balaton

Lake Balaton is a large and shallow lake that is of great economic and cultural importance in landlocked Hungary. Even though the lake has been studied extensively in the last century from a large number of scientific aspects, the mineralogy of its sediments has not been fully explored. The mud at the bottom of the lake consists mostly of silt-sized grains of carbonate minerals with compositions between those of calcite (CaCO3) and dolomite CaMg (CO3)2. In order to understand the processes of carbonate precipitation and the influence of water budget fluctuations on the mineralogical character of the sediment, we used X-ray powder diffraction to analyze the changes of cell parameters of carbonate minerals in the upper half meter of the sediment. The major carbonate phase is Mg-calcite that shows a distinct reduction in cell parameters from west to east, reflecting an increase of its Mg-content, in parallel with a gradient of dissolved Mg/Ca ratio in the water. Intriguingly, dolomite, the other widespread carbonate phase in the sediment, also shows a change in cell parameters from west to east, with the deviations from values of stoichiometric dolomite being largest in the Eastern Basin of the lake. The similar pattern of cell parameter changes of Mg-calcite and dolomite suggests that ordered dolomite with slightly anomalous, Ca-rich composition also forms in the lake, probably by direct precipitation from the water. In contrast, protodolomite forms within the sediment through diagenetic processes. Based on our X-ray powder diffraction measurements, we propose a model of carbonate mineral formation and transformation in Lake Balaton. Since the Mg/Ca ratio of the water appears to be the major factor in controlling the compositions of carbonate minerals, and this ratio in turn is governed by the amount of water supply, the properties of the precipitating carbonate minerals are affected by the actual level of the lake water

Az atomi környezet hatása erősen kötött elektronok atomi átmeneteire = Effects of the atomic environment on atomic transitions of strongly bound electronic states

3d átmeneti fémek (Cu, Ni, Co) rezonáns KLL Auger átmeneteiben rezonáns Raman folyamatokat azonosítottunk és a spektrumok alakját értelmezni tudtuk a 4p be nem töltött elektronállapotok segítségével. Eredményeink szerint a 3d elemek KLL Auger átmeneteiben a multiplett felhasadást a szilárdtest környezet csak kis mértékben változtatja meg. A Cu és Ni fémek rezonáns KLL Auger spektrumaiban kezdeti, ill. végállapoti gerjesztéseknek megfelelő szatelliteket azonosítottunk modellszámításaink és a szatellit-intenzitások fotonenergiától való megfigyelt függése alapján. Szilárd Si és Ge belsőhéj fotoelektron és KLL Auger spektrumaiban meghatároztuk a különböző módusú plazmongerjesztésekből származó járulékokat, függésüket a fotonenergiától és a kísérleti geometriától, kimutatva a belsőhéj-vakanciakeltés jelentős szerepét. Elektron-visszaszórási kísérleteinkkel és az elektrontranszport modellezésével meghatároztuk Ge esetében az elektronok rugalmatlan szórási hatáskeresztmetszetét és közepes szabad úthosszát (IMFP) széles energiatartományban. Eljárásokat dolgoztunk ki és alkalmaztunk különböző anyagoknál az IMFP felületi effektusokra történő korrigálására. Igazoltuk, hogy a rugalmasan visszaszórt elektronok spektroszkópiája alkalmas a felületi H kimutatására és a többszörös szórást figyelembe vevő szimulációnkkal kvantitatíve értelmeztük a polietilénről rugalmasan visszaszórt elektronok spektrumát. A kemény röntgensugárzással keltett elektronok nagy energiafelbontású spektroszkópiájának módszerét sikeresen alkalmaztuk röntgendetektor-válaszfüggvények, ill. ötvözetek komponensei közötti töltésátadás meghatározásában | Resonant Raman processes were identified in the resonant KLL Auger transitions of 3d metals (Cu, Ni, Co). The shape of the Auger lines was interpreted by the help of the unoccupied 4p electronic states. Our results show that the solid environment causes only a small change in the multiplet structure of the KLL Auger spectra of 3d metals. Satellites due to initial or final state excitations were identified in the resonant KLL Auger spectra of Cu and Ni metals, on the basis of our model calculations and of the observed dependence of the satellite intensities on the photon energy. In the core photoemission and KLL Auger spectra of solid Si and Ge, the contributions of plasmon excitations of various mode (dependending on photon energy and experimental geometry) were quantitatively interpreted, showing the great role of core vacancy production. From electron backscattering experiments and modeling the electron transport the cross section of inelastic scattering and the inelastic mean free path (IMFP) of electrons in Ge were determined in a wide energy range. Procedures were elaborated and applied for various materials for correcting IMFPs for surface effects. The applicability of the elastic peak electron spectroscopy for identification of surface H was proved and using our simulation accounting for multiple scattering, the spectrum of electrons backscattered elastically from polyethylene was interpreted quantitatively. The high resolution spectroscopy of electrons excited by hard X-rays was used successfully in determining response function of X-ray detectors and charge transfer between components of alloys