Savanyú vulkáni üvegek ásványtan-geokémiai vizsgálata, petrológiai és vulkanológiai kiértékelése = Mineralogical and geochemical study of acid volcanic glasses, and its interpretation from petrological and volcanological point of view

Változatos lemeztektonikai környezetben képződött obszidián minták fő- és nyomelemtartalmának összehasonlító vizsgálata során megállapítottuk, hogy az eredetileg gránitokra kidolgozott diszkriminációs diagramok alkalmazhatók a savanyú kiömlési kőzetek esetében is. Megállapítottuk, hogy az óceáni sziget bazaltok (OIB) és a szigetív mészalkáli bazaltok (IAB) chondritra normált spiderdiagramjainak néhány alapvető jellegzetessége (pl. a relatív Nb-Ta minimum, ill. relatív Nb-Ta maximum) az obszidiánminták spiderdiagramjának patternjénél is felismerhető. Vizsgáltuk a mikro-PIXE elemzések megbízhatóságát és felhasználhatóságát, s bemutattuk, hogy az ezzel a módszerrel készített piroxénelemzési eredmények alkalmasak geotermometriai számítások elvégzésére. Savanyú vulkáni üvegek mállási folyamatát riolittuffa mintákon vizsgáltuk. A minták ásványos és főelem-összetételének valamint termoanalitikai paramétereinek (TG) összehasonlítása alapján megállapítottuk, hogy a mállási fok jellemzésére egyes TG paraméterek a nemzetközi gyakorlatban elterjedt indexhez (CIA) hasonló megbízhatósággal rendelkezik. Részt vettünk egy olyan berendezés kifejlesztésében, ami magas hőmérsékleten direkt mintavételt tesz lehetővé tömegspektrometriai vizsgálatokhoz. E berendezést vulkáni üvegek termális bomlási folyamatainak tanulmányozásánál is hasznosítani lehet. | Major and trace element spectra of obsidian samples from various tectonic settings were performed by LA-ICP-MSand PIGE techniques. The results suggest that discrimination diagrams for granites may be used for acidic volcanic rocks, too. We found that some characterisctic patterns of chondrite normalised spider diagram of OIB and IAB (such as relative Nb-Ta minimum and relative Nb-Ta maximum, respectively) can be observed in the case of obsidians, too. We demonstrate that analytical data yielded by micro-PIXE measurements can be applied even for geothermometric estimations. Weathering process of acidic volcanic glasses was studied on rhyolite tuff samples. Comparing mineralogical and major element composition as well as some thermoanalytical parameters of the samples it can be stated on the basis of some TG parameters weathering degree of rhyolite tuffs can be determined with a reliability that similar to that of the internationally accepted CIA index. We participated in construction of high temperature direct probe coupled to a quadrupole MS. This device can be also used for monitoring thermal decomposition of volcanic glasses

Protonnyalábos mikromegmunkálás = Proton beam Micromachinig

A téma keretében a mikromegmunkálás módszerét telepítettük az ATOMKI pásztázó proton mikroszondájához. Második lépésben különböző nyomdetektor és más reziszt anyagokat vizsgáltunk a mikromegmunkálás szempontjából. A megmunkált anyagok különböző jellemzőit vizsgáltuk a besugárzási paraméterek függvényében. Az előállított eszközök (mikrostruktúrák) alkalmazási lehetőségeit fel kívántuk kutatni, mikrostruktúrákat állítottuk elő demonstrációs és konkrét alkalmazási célból. A világon második kutatócsoport lettünk e témában, szerepünk azonban nem másodrendű. Kihasználva saját adottságainkat, a nemzetközi irodalomhoz új kutatási eredményekkel járultunk hozzá. Az ATOMKI pásztázó proton mikroszondája így egy új, perspektivikus alkalmazási területet nyert. | We have installed the Proton Beam Micromachining (PBM) / P-beam Writing (PBW) method on the Scanning Nuclear Microprobe of ATOMKI. We have investigated various solid state nuclear track detector and other resist materials for micromachining properties. We have characterized various properties of materials as a function of irradiation parameters. We have explored the potential application areas of the produced microstructures. We have created products for demonstration and real application purposes. We became the second research group in the world in this field, but our role is not of secondary importance. Exploiting our resources, we have added new scientific results to the literature. The Scanning Nuclear Microprobe of ATOMKI has gained a new, prosperous application area

Characterization of urban aerosol sources in Debrecen, Hungary

Debrecen is an average middle European city from the point of view of aerosol pollution. Its locationmakes the city an ideal place for observing aerosol transport processes. Systematic investigation ofatmospheric aerosol of the east-Hungarian region has been performed in the Institute of NuclearResearch of the Hungarian Academy of Sciences for 20 years by accelerator based elementalanalytical technique. As a complementation of this research we observed the size distribution andshort-term time variation of the elemental component of fine (PM2.5) and coarse (PM10-PM2.5) urbanaerosol in the frame of sampling campaigns during 2007 and 2008 in a downtown site of Debrecen.Meteorological parameters were also recorded parallel to the aerosol sampling. Elementalconcentrations (Z ≥ 12) were determined by particle induced X-ray emission (PIXE) analyticaltechnique at the Laboratory of Ion Beam Applications (IBA) of the ATOMKI. On the obtaineddatabase six sources of the urban aerosol were identified: 2 types of soil, domestic heating, sulphateoriginating from long range transport processes, an unidentified source enriched with chlorine andtraffic. Emission episodes were also observed. The short-time variation of urban aerosol combinedwith meteorological data and with mass size distribution serves as a basis to reach a betterunderstanding of the aerosol sources in receptor areas, to select local emission and long rangetransport episodes, to follow the evolution of aerosol, and to make a better estimate on the healthimpact

MOLYBDENUM DOPED CARBON AEROGELS WITH CATALYTIC POTENTIAL

Mo-doped carbon aerogels were obtained in the polycondensation reaction of aqueous resorcinol and formaldehyde by adding Mo-salt at two different stages of the synthesis: i) to the initial sol; ii) by incipient wetting impregnation of the supercritically dried polymer gel. Molybdenum added during the polymerization yielded a more compact gel structure with practically no mesoporosity. With post-impregnation, by contrast, mesopores of diameter 3-15 nm were generated. Carbonization appreciably enhanced the microporous character of both samples, but in the mesopore range their pore size distribution was conserved. The Mocontent of the samples was also different: Mo was lost during the solvent exchange before the supercritical drying (i.e., the Mo failed to bind chemically to the polymer matrix). The residual Mo congregated into 25-60 nm bulk clusters of α-Mo2C. In the other carbon aerogel, finely dispersed α-Mo2C and η-Mo3C2 crystals formed, of size 8-20 nm. On the surface of both carbons the Mo formed oxides. In the model test reaction (acetic acid hydroconversion) the catalytic activity of both carbon aerogels was enhanced by molybdenum. The more open pore structure, higher concentration and finer Mo distribution, as well as its chemical form, may all be responsible for the greater conversion and higher value products obtained with the post-impregnated sample

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements