A kisfeszültségű villamos elosztóhálózat hibacím ütemező rendszerelméleti megközelítése = System Theory Approach of the Low Voltage Distribution Network Fault Scheduler

A villamosenergia-szolgáltatásban számos ok miatt — például szélsőséges időjárási viszonyok — keletkeznek hibák. A nem tervezett, áramszünetet okozó hibák javítását a szerelők ütemezetten végzik. Az ütemezést speciális informatikai támogatás segíti. A szerelőknek jól meghatározott szabályrendszer szerint osztják ki a feladatokat. Jelen cikk írói arra vállalkoztak, hogy a meglévő ütemező rendszert új megközelítésben, tudományos módszerekkel vizsgálják és javaslatokat tegyenek új és hatékonyabb eljárások bevezetésére. Az új megközelítés alkalmazásával az ütemező rendszerek hatékonyságának mérése valósul meg, míg az új eljárások bevezetésével az ütemező optimálisabban működik

AMS 14C and OSL/IRSL dating of the Dunaszekcső loess sequence (Hungary): chronology for 20 to 150 ka and implications for establishing reliable age-depth models for the last 40 ka

As revealed by 18 AMS radiocarbon and 24 OSL/IRSL ages the Dunaszekcső loess-paleosol sequence is an excellent terrestrial record of paleoenvironmental change in the Carpathian Basin for the last 130 ka, with significant soil forming episodes during the Eemian interglacial (130 to 115 ka, MIS 5e) and in some subsequent MIS 5 stages, and distinct periods of loess accumulations during the MIS 4 and MIS 2. Charcoals from the sequence made it possible to test the accuracy of 14C ages from mollusc shells. This approach revealed that 14C ages from some gastropods having small shells (<10 mm) (Succinella oblonga, Vitrea crystallina) are statistically indistinguishable from the ages of charcoals, while others (Clausiliidae sp., Chondrula tridens) show age anomalies up to 600-800 years. OSL and pIRIR@290 ages are found to be consistently older, while post-IR OSL ages are younger than the 14C ages from charcoals and molluscs by some thousands of years, except for pIRIR@225 ages that match the radiocarbon ages quite well. OSL and IRSL ages have scatters up to 7-10 thousand years within 40 ka, while charcoals and small molluscs yield consistent ages with relatively low variability. Beyond the observation that some small molluscs seem to yield reliable 14C ages, calibrated 2σ age ranges of the radiocarbon data (ca. 500‒800 years for 20 to 30 ka) are an order of magnitude narrower than those of the OSL/IRSL methods (1800 to 4000 years for 25 to 35 ka). Thus, for establishing chronologies within 40 ka, which are both accurate and precise enough to address issues like synchroneity of millennial-scale paleoenvironmental events across regions (e.g. North Atlantic and Europe), AMS radiocarbon dating of shells of specific loess molluscs and charcoals may probably be a powerful chronological tool. However, additional work is definitely required involving 14C and OSL/IRSL dates from other loess sequences to further test the performance of these two supposedly robust chronometers

Lösz-paleotalaj sorozatokban megőrződött fitolitkészletek környezettörténeti és környezet régészeti vonatkozású kutatási lehetőségei = Environmental History and Environmental Archaeological Research Opportunities of Phytoliths Preserved in Loesspaleosoil Series

A fitolitok növények által termelt opálszemcsék, amelyek bizonyos tulajdonságaiknak köszönhetően (pl. nagy mennyiségben termelődnek, diagnosztikai értékkel bíró morfotípusok létezése, viszonylag nagy ellenállóképesség) az egykori (lokális) vegetáció indikátorai. Talajokból, üledékekből, üledékes kőzetekből kinyert fitolitkészlet értékes proxy adatot jelenthet a környezetrekonstrukciós vizsgálatokhoz. Régészeti kontextusból gyűjtött fitolitok az ember táj- és növényhasznosításának rekonstrukciójában játszhatnak fontos szerepet. A fitolitkészlet megfelelő kiértékeléséhez elengedhetetlen a fitolitkészletet ért tafonómiai folyamatok ismerete, hatásuk becslése. Lösz-paleotalaj sorozatok jelentős kiterjedésben és vastagságban borítják a szárazföldek felszínét. A lösz-paleotalaj sorozatokból kinyert fitolitkészleteket ennélfogva nagy kiterjedésű területen, jelentős időtávot (elsősorban a negyedidőszakot) átfogva lehet felhasználni a környezetrekonstrukciós vizsgálatok során. A fitolitkészlet környezetrekonstrukciós vizsgálatokban történő megfelelő kiértékeléséhez szükséges ismerni a lösz-paleotalaj sorozatok esetében érvényesülő főbb tafonómiai folyamatokat. A fitolitok lösz-paleotalaj sorozatokban történő megőrződését befolyásoló folyamatok jobb megismerése megbízhatóbb környezetrekonstrukciót tesz lehetővé

Pleistocene vertebrate faunas of the Süttő Travertine Complex (Hungary)

Numerous fossil remains (vertebrates, molluscs and plants) were found in more than twenty sites of the Süttő Travertine Complex during the last 150 years. The majority of these remains were recovered from fissures of the travertine, but also from the travertine and an overlying loess-paleosol sequence. The aims of this study were to review the fossil content, to determine the stratigraphical positions of the various vertebrate faunas of Süttő and provide paleoecological interpretation of the periods on the basis of their faunas and floras. In addition, this paper describes new faunas and floras from the sites Süttő 16–20 and provides 14C dates for Süttő 16. On the basis of the new uranium series isotope and optical dating (OSL), the age of the travertine complex is Middle Pleistocene (235±21–314±45 ka, MIS 7–9), while the age of the loess-paleosol sequence in superposition of the travertine is Middle-Late Pleistocene (MIS 2–MIS 6). In contrast, the fossils of the travertine indicated an older, Pliocene–Early Pleistocene age. A fissure (Süttő 17) and a red clay layer (Süttő 19) contained mammal faunas of Early–Middle Pleistocene age. These results indicated the existence of older travertine in certain quarries (Hegyháti quarry, Cukor quarry). Sedimentological and OSL data of well-dated layers of the loess-paleosol sequence (Süttő/LPS) at Süttő allowed a correlation with the layers of Süttő 6. The paleosol layer in the upper part of the sequence of Süttő 6, was correlated with a pedocomplex of the overlying loess-paleosol sequence, which was dated to MIS 5c (upper, dark soil) and MIS 5e (lower, reddish brown soil). The paleoecological analysis of the mammal and mollusc faunas supported the former interpretation of Novothny et al., inferring warm, dry climate during the sedimentation of the upper layers, and more humid climate for the lower layers). However, the fauna of the lower soil layer indicated cold climate, so an age of MIS 5d is suggested. Dating of the fissure faunas is based on similarity studies. For some faunas, this method cannot be used, because of the low number of species. On the basis of the species compositions and former interpretations, these faunas originated mainly from sediments that were deposited under cold climatic conditions. Other fissure faunas were dated by AMS 14C (Süttő 16), or by correlation with soil layers of Süttő 6. According to these results, most of the fissure faunas can be correlated with different phases of MIS 5. However, there are a younger (MIS 2) and an older (Early–Middle Pleistocene) fissure fauna.status: publishe

Lessons from the AMS 14C and OSL/IRSL-dating of the Dunaszekcső loess record, Hungary

Reliable chronologies are prerequisites of appropriate proxy interpretations from terrestrial archives of Quaternary climate and environmental change. Loess records may provide a wealth of paleoenvironmental information, yet they are usually poorly dated. This mostly means low resolution dating of loess profiles and also imprecise chronologies, i.e. age-depth models that have uncertainties of millennial magnitude. This prevents us from addressing issues like synchroneity of abrupt climatic/environmental events on millennial time scales. Two different means of dating are commonly applied for loess sequences: luminescence and radiocarbon dating. Major problems are low precision of luminescence ages and the general lack of organic macrofossils (e.g. charcoal) in loess that can reliably be dated using 14C. Other datable phases in loess are mollusc shells, rhizoliths and organic matter. Evidences are growing that rhizoliths are unreliable phases for 14C-dating and organic matter 14C ages are often seriously compromised by rejuvenation in loess sequences. Also mollusc shells are often regarded as unreliable material for 14C-dating, as they may incorporate 14C-deficient (or dead) carbon from the local carbonate-rich substrate during shell formation, thereby producing anomalously old ages by up to 3000 years. In this study an attempt has been made to address some of the dating issues and problems mentioned above by triple-dating (AMS 14C and OSL/IRSL) of the Dunaszekcső loess-paleosol sequence (South-Hungary). While the OSL/IRSL techniques directly date the sediment (quartz and K-feldspar grains) and provide burial ages, radiocarbon yield ages from phases like organic matter, mollusc shells and rhizoliths and determines the time elapsed since the living system was last in equilibrium with atmospheric 14C and became closed after burial. As revealed in this study all loess rhizoliths sampled at three different depths (4.00 m: 9744-10156 2σ age range in cal yr BP, 5.00 m: 8013-8167 cal yr BP and 6.00 m: 9534-9686 cal yr BP) yield Holocene ages, so absolute ages cannot be gained this way for loess deposition. As charcoals are widely accepted as phases yielding very reliable 14C ages, mollusc shell 14C ages were tested against charcoal ages. Here we focused on molluscs with smaller (< 10 mm) shells as some evidence exists that some species do not incorporate dead carbon into their shells or at least in low amounts. Our results demonstrate that Succinella oblonga and Vitrea crystallina yield statistically indistinguishable ages (2σ age ranges: 29990-30830 and 29600-30530 cal yr BP) when compared with the charcoal 14C age (29960-30780 cal yr BP, depth 8.20 m), and others like Clausilia sp. and Chondrula tridens give slightly older ages than the charcoals and show larger age anomalies (500-900 14C yr). Compared to the charcoal ages at 8.20-8.25 m depth, the post-IR IRSL225 age of 28520±1120 yr (2σ age range: 26280-30760 yr) from a depth of 7.75 m match quite well the charcoal ages (Dsz-Ch1, 2σ: 29960-30780 cal yr BP and Dsz-Ch2, 2σ: 29350-30150 cal yr BP). At the same time, the post-IR OSL approach seems to slightly underestimate (2σ: 20640-26960 yr), while the post-IR IRSL290 overestimate (2σ: 30260-37100 yr) the expected/true age of deposition at the respective depth (7.75 m). At a depth of 4.00 m, slight underestimation of mollusc AMS 14C ages (Trochulus hispidus, 2σ: 22370-22740 cal yr BP, Arianta arbustorum, 2σ: 24470-25120 cal yr BP) by post-IR OSL (2σ: 17140-21980 yr) and a moderate to significant overestimation by OSL (2σ: 26760-33800 yr) and post-IR IRSL290 (2σ: 27660-35740 yr) has been recognized. Again, the post-IR IRSL225 age (2σ: 23180-26900 yr) lies the closest to the AMS 14C ages. To decide which technique, AMS 14C or OSL/IRSL yields more accurate ages is not possible without independent absolute chronological data based on another method. Yet, we think that the consistent 14C ages of charcoals and small molluscs (two phases having very different origin and genesis) suggest that these ages are reliable and may reflect the real age of sedimentation. Clearly, the precision of 14C ages are an order of magnitude better (calibrated 2σ age ranges 500-800 yr) than the luminescence ages (2σ age ranges: 3700-7900 yr) and this may be another reason for creating age-depth models based purely on 14C ages, if high precision is needed. The use of a mixture of ages (i.e. 14C and OSL/IRSL) seems to counterproductive in this respect and we suggest to separate the results of the two techniques in modeling. OSL/IRSL-based age models are useful in checking the accuracy of 14C-based chronologies for the last 50 ka and vice versa and proxy interpretations should be tested against both 14C and OSL/IRSL age models independently

Tectonic and climatic control on terrace formation: Coupling in situ produced 10Be depth profiles and luminescence approach, Danube River, Hungary, Central Europe

International audience\textcopyright 2015 Elsevier Ltd.The terrace sequence of the Hungarian part of the Danube valley preserves a record of varying tectonic uplift rates along the river course and throughout several climate stages. To establish the chronology of formation of these terraces, two different dating methods were used on alluvial terraces: exposure age dating using in situ produced cosmogenic 10Be and luminescence dating. Using Monte Carlo approach to model the denudation rate-corrected exposure ages, in situ produced cosmogenic 10Be samples originated from vertical depth profiles enabled the determination of both the exposure time and the denudation rate. Post-IR IRSL measurements were carried out on K-feldspar samples to obtain the ages of sedimentation.The highest terrace horizon remnants of the study area provided a best estimate erosion-corrected minimum 10Be exposure age of \textgreater700 ka. We propose that the abandonment of the highest terrace of the Hungarian Danube valley was triggered by the combined effect of the beginning tectonic uplift and the onset of major continental glaciations of Quaternary age (around MIS 22). For the lower terraces it was possible to reveal close correlation with MIS stages using IRSL ages. The new chronology enabled the distinction of tIIb (~90 ka; MIS 5b-c) and tIIIa (~140 ka; MIS 6) in the study area. Surface denudation rates were well constrained by the cosmogenic 10Be depth profiles between 5.8 m/Ma and 10.0 m/Ma for all terraces. The calculated maximum incision rates of the Danube relevant for the above determined \textgreater700 ka time span were increasing from west (\textless0.06 mm/a) to east (\textless0.13 mm/a), toward the more elevated Transdanubian Range. Late Pleistocene incision rates derived from the age of the low terraces (~0.13-0.15 mm/a) may suggest a slight acceleration of uplift towards present

Late Pleistocene millennial scale cycles of aeolian sedimentation in the Dunaszekcső loess record, south Hungary: preliminary data and interpretations

Millennial scale warm-cold oscillations in air temperature over Greenland and rapid sea surface temperature changes were recorded in ice cores and North Atlantic sediments for the last glaciation. These events must have been associated with profound environmental changes in Europe, and indeed, millennial scale oscillations in grain size records have been found in loess deposits of Europe and Asia. Unfortunately, the timing of these events are still unresolved due to chronological uncertainties on the order of thousands of years. Major problems are the low precision of luminescence ages and the general lack of materials that can reliably be dated using 14C. As demonstrated by 24 OSL/IRSL ages, the Dunaszekcső loess-palaeosol sequence is an archive of climate and environmental changes of the last glacial-interglacial cycles. For the upper part of the section (<33 cal yr BP), the chronology is further refined based on charcoal and mollusc shell radiocarbon ages. Here we show that AMS 14C ages of some mollusc species having small shells (<10 mm) seem to yield reliable ages in a comparison with charcoal 14C ages. These radiocarbon ages are consistent, have low variability and define age-depth models with sufficient precision to examine the timing of paleoenvironmental changes in the context of North Atlantic climatic variations. Bayesian age-depth modeling was performed using Bacon for a depth of 865-500 cm and a time span of 33-25 kyr based on 16 radiocarbon ages. Mean confidence ranges are 674 yr with a minimum of 416 yr at 630 cm and a maximum of 917 yr at 865 cm. Such a sub-millennial scale age model precision has formerly been unprecedented for loess profiles. Sedimentation rates calculated from the Bayesian age-depth model vary between 0.3 and 1.1 mm year‒1 (=m kyr‒1) with the maximum at 27.390±230 cal yr BP. Estimated bulk dust flux for the studied site and the given time span range from 493 to 1666 g m‒2 yr‒1, calculating with a dry density of loess of 1500 kg m‒3. Both the sedimentation rate and dust flux show millennial scale variations, together with the median grain size (Md) of bulk loess that is considered an integrated proxy of wind strength, dust source distance and source aridity. The Md proxy reveal sub-millennial scale variations, too, but the interpretation of such oscillations are far from straightforward. Nevertheless, the millennial scale variations in the Aeolian sedimentation imply strong and rapid changes in the frequency (and magnitude?) of dust storm events for the period of 33-25 kyr. Further preliminary observations are that grain size (Md) maxima lag behind the NGRIP dust peaks (Ca2+) by ca. 300-500 years and grain size minima closely follows Ca2+ and δ18O minima (GI-4 and 3). It must be noted, however, that the 300-500 years lags are within age model uncertainties

Integration of new and revised chronological data to constrain the terrace evolution of the Danube River (Gerecse Hills, Pannonian Basin)

Terrace ages deduced from diverse geochronological records yielded inconsistent data in the Danube valley in Hungary. The problem of discrepancies in the different chronological datasets has to be resolved before the Quaternary tectonic and climatic processes leading to valley incision and terrace formation may be properly evaluated. To establish a more robust chronology of the Danube valley in Hungary, new cosmogenic nuclide- (⁠10Be depth profiles, ⁠26Al/⁠10Be burial durations and burial depth profile) and luminescence-based (pIRIR⁠290) terrace ages were acquired and compared to revised paleontological and published U/Th and magnetostratigraphic data. All the applied geo-chronometers led to concordant terrace ages, with the exception of the U/Th method applied on travertine deposits covering terraces. U/Th ages predating the last interglacial manifest a bias towards younger ages, and so they were ignored in relation to the quantification of terrace ages. As a result, terrace ages from the Late Pliocene to Late Pleistocene were settled. With regard to data from the Middle Pleistocene onwards, the combination of diverse methodologies led to a tighter bracketing of terrace ages than would be possible using a single dating method. The modelling of cosmogenic ⁠26Al and ⁠10Be concentrations enabled to derive surface denudation rates and their combination with paleontological data also allowed us to decide between diverse landscape evolution scenarios