353 research outputs found

    Secondary succession of overgrazed Pannonian sandy grasslands

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    We assessed vegetation changes on acidic sandy soils in permanent plots to follow secondary succession after cessation of intensive goose breeding in E Hungary.We also aimed to estimate the time required for vegetation regeneration and indicate differences in secondary succession patterns at different altitudes in sand dunes. Two sites in the low and two in the high parts of the dunes were chosen and sampled for twelve years. The initial stages are characterized by ruderal communities dominated by nitrophilous annual weeds. Ruderal vegetation was soon replaced by nutrient-poor communities dominated by short-lived pioneer dicotyledonous plants and grasses. In the last few years of the study, coinciding with a rainy period, the low sites were dominated by the perennial grasses, Poa angustifolia, P. pratensis and Cynodon dactylon. In contrast, in the high sites a less dense cover of perennials developed. The influence of initial composition on vegetation development decreased with time and the influence of altitude increased during succession. The altitude of the site had a significant effect on regeneration. Species richness and Shannon diversity of the high sites increased during vegetation development and that of the lowsites decreased. Most annuals persisted in the high sites but became extinct in the low sites. The mean species turnover rate, irrespective of altitude, decreased during the study

    Engineering Geological Survey for Railway Extension in the Nile Valley

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    Egyptian National Railway (ENR) called for a tender for doubling the railway line Edfu/ Aswan in the mountainous terrain. The engineering geological works were carried out by the authors for MÁVTI Co. Ltd. The study includes two parts El Serag and El Gaafera sections having a length of 6.5 km. One side of the railway track is bordered by steep sandstone cliffs of 30 - 40 m in height that forms the edge of rugged low relief topography often dissected by wades. The other side is on the right bank of the Nile where a narrow flood plain is cultivated and covered by dense vegetation. Several alternatives were studied for the second rail track including tunnel open cut, rock excavation, land bridge and gabion versions. ENR chose the rock excavation version. As a consequence the cliff wall geometry, joint system and rock formations were studied in details. By using these data the necessary rate of rock excavations, the schedule of works, machinery, safety conditions and excavation methods - blasting, swelling cement - were prepared. Finally swelling cement was used by Egyptians. No Hungarian expertise was used during the construction phase

    ÖkolĂłgiai szemlĂ©letƱ gyeptelepĂ­tĂ©s elmĂ©lete Ă©s gyakorlata - mĂĄsodik kiadĂĄs

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    A könyv mĂĄsodik, bƑvĂ­tett kiadĂĄsa a mƱvelĂ©s alĂłl kivett terĂŒletek ökolĂłgiai szemlĂ©letƱ gyepgazdĂĄlkodĂĄssal törtĂ©nƑ hasznosĂ­tĂĄsa esetĂ©n nyĂșjt ĂĄtfogĂł segĂ­tsĂ©get. RĂ©szletezi többek között az ökolĂłgiai gyeptelepĂ­tĂ©s szempontjait, gyakorlatĂĄt, a vĂĄrhatĂł gĂ©p- Ă©s költsĂ©gszĂŒksĂ©gletet

    Recenzió: A nemes- és színesfémek régészete, története és népraja a Kårpåt-medencében - Készítéstechnikai, archeometriai és tårsadalomtörténeti megközelítések

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    Az ELKH BölcsĂ©szettudomĂĄnyi KutatĂłközpont Ă©s az MTA BTK RI LendĂŒlet MobilitĂĄs KutatĂłcsoport tĂĄmogatĂĄsĂĄval 2021-ben kiadott konferenciakötet kĂ©t olyan mƱhelykonferencia elƑadĂĄsaibĂłl kĂ©szĂŒlt tanulmĂĄnyok reprezentatĂ­v vĂĄlogatĂĄsa, amelyek a bronzmƱvessĂ©g, illetve a szĂ­nes- Ă©s nemesfĂ©mek rĂ©gĂ©szetĂ©t, korabeli technikĂĄjĂĄt-technolĂłgiĂĄjĂĄt tĂĄrgyaltĂĄk kifejezetten multidiszciplinĂĄris fĂłkuszban. Az ankĂ©tokon, igen szĂ©les idƑsĂ­kot ĂĄtölelve, esettanulmĂĄnyok Ă©s ĂĄtfogĂł, tematikus elƑadĂĄsok formĂĄjĂĄban a KĂĄrpĂĄt-medence szĂ­nes- Ă©s nemesfĂ©m-kultĂșrĂĄjĂĄnak kisebb-nagyobb szeletĂ©t, valamint az azokhoz kötƑdƑ kutatĂĄsok eredmĂ©nyeit prezentĂĄltĂĄk rĂ©gĂ©szek, törtĂ©nĂ©szek, nĂ©prajzosok, mƱszaki Ă©s termĂ©szettudomĂĄnyi szakemberek

    Recension: The archaeology, history and ethnography of the precious and non-ferrous metals in the Carpathian basin

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    This conference proceedings, published in 2021, is a representative selection of studies from two workshops which discussed the bronze working and archaeology as well as contemporary technologies and techniques of non-ferrous and precious metals, with a specific multidisciplinary focus. At the conferences, archaeologists, historians, experts of ethnography, technology, and natural sciences presented case studies and comprehensive thematic presentations covering a very broad time span, as well as the results of research on various aspects of the non-ferrous and precious metal culture of the Carpathian Basin

    IntegrĂĄlt (botanikai Ă©s zoolĂłgiai) konzervĂĄciĂł-ökolĂłgiai kutatĂĄsok gyepek termĂ©szetközeli ĂĄllapotĂĄnak visszaĂĄllĂ­tĂĄsĂĄra, biodiverzitĂĄsĂĄnak megƑrzĂ©sĂ©re Ă©s növelĂ©sĂ©re = Integrated botanical and zoological research in conservation ecology to restore, conserve and increase grassland biodiversity

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    A biodiverzitĂĄs-vĂ©delem egyik jelentƑs feladata a fogyatkozĂł fajok szĂĄmĂĄra megfelelƑ Ă©lƑhelyek lĂ©tesĂ­tĂ©se. KutatĂĄsunkban a termĂ©szetes növĂ©ny- Ă©s ĂĄllatfajok visszatelepĂŒlĂ©sĂ©t vizsgĂĄltuk EurĂłpa legnagyobb terĂŒletƱ, szĂĄntĂłkon vĂ©gzett gyeprekonstrukciĂłs programjĂĄban. A tervek szerint kiĂ©pĂ­tettĂŒk mintavĂ©teli helyeinket Ă©s elvĂ©geztĂŒk a terepi felmĂ©rĂ©seket. ElkĂ©szĂ­tettĂŒk a vizsgĂĄlt 7000 hektĂĄros tĂĄj Ă©lƑhelytĂ©rkĂ©peit Ă©s kialakĂ­tottuk a projekt egysĂ©ges adatbĂĄzisĂĄt. Az adatok alapjĂĄn Ă©rtelmeztĂŒk a gyeprekonstrukciĂł elsƑ hĂĄrom Ă©vĂ©ben zajlĂł ökolĂłgiai folyamatokat. Kimutattuk, hogy kevĂ©s fajt tartalmazĂł magkeverĂ©kek vetĂ©se is jelentƑsen felgyorsĂ­thatja a növĂ©nyzet visszatelepĂŒlĂ©sĂ©t a felhagyott lucernaföldeken. Hajdani gabona- Ă©s napraforgĂł-földeken a gyeptakarĂł lassabban alakul vissza Ă©s a gyomok visszaszorĂ­tĂĄsĂĄra tovĂĄbbi kezelĂ©sek (legeltetĂ©s, kaszĂĄlĂĄs) szĂŒksĂ©gesek. A termĂ©szetes gyepekre jellemzƑ Ă­zeltlĂĄbĂș fajok a rekonstrukciĂłt követƑ mĂĄsodik Ă©vre vĂĄltottĂĄk fel a szĂĄntĂłkra jellemzƑ tĂĄgtƱrĂ©sƱ fajokat. A madarak közĂŒl a rekonstrukciĂł elsƑsorban a mezƑgazdasĂĄgi terĂŒletekhez kötƑdƑ, EurĂłpa-szerte fogyatkozĂł fajoknak kedvezett. A tapasztalatok alapjĂĄn ĂĄttekintƑ tanulmĂĄnyban bemutattuk a tĂĄjszintƱ Ă©lƑhely-rekonstrukciĂł elƑnyeit, gyakorlati kivitelezĂ©si lehetƑsĂ©geit Ă©s költsĂ©geit. A pĂĄlyĂĄzat rĂ©vĂ©n 9 impakt faktoros Ă©s 7 hazai cikket jelentettĂŒnk meg, 12 elƑadĂĄst tartottunk nemzetközi konferenciĂĄkon Ă©s lefektettĂŒk egy nemzetközi szinten is versenykĂ©pes kutatĂłcsoport alapjait. | The creation or restoration of habitats suitable for declining species is an important task in biodiversity conservation. We studied the recolonisation of natural plant and animal species in the largest grassland restoration programme in Europe. We established permanent plots and carried out field surveys as planned. We prepared the habitat maps of the 7000-ha landscape and developed a unified database for the project. We interpreted the ecological processes occurring in the first three years after restoration based on the data collected. We showed that restoration using low-diversity seed mixtures can considerably accelerate the recolonisation of natural vegetation on former alfalfa fields. On former wheat and sunflower fields, grass cover forms slower and further management (grazing, mowing) is necessary to control weeds. Arthropod species characteristic to natural grasslands replaced generalist species characteristic to croplands by the second year after restoration. Within birds, the restoration primarily favoured those species of agricultural areas that are declining all over Europe. Based on the experience gained, we demonstrated the benefits, practical implementation and costs of landscape-scale restoration in Europe in a review. As a result of the project, we published 9 papers in ISI-listed journals, 7 papers in Hungarian journals, presented 12 talks at international conferences and laid the foundations of an internationally competitive research group

    A mezƑgazdasĂĄgban alkalmazott axiĂĄlis ĂĄtömlĂ©sƱ ventilĂĄtorok nyomĂĄs- Ă©s sebessĂ©gterĂ©nek meghatĂĄrozĂĄsĂĄra alkalmas vizsgĂĄlati mĂłdszer tovĂĄbbfejlesztĂ©se = Developing of the method for measurement of velocity- and pressure field of axial flow fan and its application in agriculture

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    A mezƑgazdasĂĄgban alkalmazott egyszerƱ geometriĂĄjĂș Ă©s egyszerƱen gyĂĄrthatĂł ventilĂĄtorok mĂ©rĂ©sĂ©nek Ă©s mĂ©retezĂ©sĂ©nek tovĂĄbbfejlesztĂ©se terĂ©n lĂ©ptĂŒnk elƑre. A mĂ©rĂ©s tovĂĄbbfejlesztĂ©sĂ©ben a nyomĂĄs Ă©s sebessĂ©gtĂ©r mĂ©rĂ©sĂ©t pontosĂ­tottuk a mintavĂ©telezĂ©s Ă©s kiĂ©rtĂ©kelĂ©s tovĂĄbbfejlesztĂ©sĂ©vel. Az egyszerƱ ventilĂĄtorok nĂ©hĂĄny tĂ­pusĂĄnĂĄl a perdĂŒletapadĂĄs kimĂ©rĂ©sĂ©vel mĂłdosĂ­tani tudtuk a mĂ©retezĂ©si eljĂĄrĂĄst a lapĂĄtszĂĄmra vonatkozĂł ideĂĄlis nyomĂĄsnövekedĂ©s bevezetĂ©sĂ©vel. Ezen a terĂŒleten fƑkĂ©nt MolnĂĄr IldikĂł tevĂ©kenykedett Ă©s majdnem elkĂ©szĂŒlt PhD Ă©rtekezĂ©sĂ©nek ez alkotja a fƑ gerincĂ©t. A nagyobb lĂ©gteljesĂ­tmĂ©nyekre kĂ©pes ventilĂĄtorok csoportjĂĄnak tervezĂ©sĂ©vel is foglalkoztunk, fƑkĂ©nt a rĂĄcsszĂĄmĂ­tĂĄs irodalmi ĂĄttekintĂ©sĂ©vel Ă©s az anomĂĄliĂĄk feltĂĄrĂĄsĂĄval Ă©s a helyes eredmĂ©nyek alkalmazĂĄsĂĄval. Ezt elsƑsorban Fenyvesi DĂĄniel dolgozta ki a szintĂ©n majdnem elkĂ©szĂŒlt PhD Ă©rtekezĂ©sĂ©ben. A fenti tĂ©mĂĄkban több TDK dolgozat is szĂŒletett. CFD szĂĄmĂ­tĂĄsĂĄra több irĂĄnyban lĂ©ptĂŒnk. EgyĂŒttmƱködĂŒnk a koreai CEDIC co. Ltd-vel, az ĂĄltaluk kifejlesztett kĂłd eredmĂ©nyeivel összehasonlĂ­tjuk a mĂ©rĂ©si eredmĂ©nyeinket. | We have made some steps at the development of design and measurement of simple geometry and simply manufacturing axial flow fans used in agriculture. In the measuring the pressure and velocity field it was refined the data logger system and the evaluation. It was measured the vortex shrinkage at different simple axial flow fans and we have modified the ideal total pressure rise for infinite blade number to total pressure rise for finite blade number. IldikĂł MolnĂĄr investigated in this field and she will have finished the PhD thesis in the not far future. It was also investigated the higher efficiency group of axial flow fans, where the blade numbers are higher, like a grid. Fenyvesi DĂĄniel, PhD student investigated the different types of design method. He had found some discrepancies in the literatures and he worked out a design method with the help of correct grid calculation method. He will have finished the PhD thesis in the not far future, too. Some TDK theses were worked in this OTKA program. We have made some steps forward with the CFD calculation, too. There is cooperation with the Korean CEDIC co. Ltd, and we can do a comparison between the measured result and their calculation results
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