12 research outputs found

    Application of selected probability distributions of extreme values to flood risk assessment in the Odra River catchment in Lower Silesia

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    Analizie poddano maksymalne dobowe przepływy w Odrze zmierzone w latach 1971–2013 w stacji hydrologicznej w Malczycach. Z całego zbioru danych wyselekcjonowano maksymalne przepływy roczne i do ich rozkładu empirycznego dopasowano trzy rozkłady teoretyczne – Gumbela, Frecheta i logarytmiczno-normalny. Przedstawiony przykład analizy probabilistycznej zagrożenia powodziowego w dorzeczu Odry na Dolnym Śląsku może być skutecznym narzędziem w ocenie wystąpienia ryzyka powodziowego. Otrzymane w ten sposób wyniki mogą zostać wykorzystane do szacowania prawdopodobieństwa wystąpienia określonych zdarzeń związanych z zagrożeniem powodziowym, a także do porównywania wybranych obszarów dorzecza pod względem zagrożenia powodziowego.The maximum daily flows in the Oder river from the period of 1971 to 2013 were analyzed in Malczyce hydrological station. From the entire data set the maximum annual flows were selected and their empirical distributions were fitted against the three theoretical distribution models: Gumbel, Frechet and the lognormal. The presented case of probabilistic flood risk analysis for the Oder catchment in Lower Silesia may become an effective flood risk assessment tool. The results may be employed to probability assessment of certain events related to flood risk and also to compare the flood risk in selected catchment regions

    Application of the Extreme Values Theory to Assess the Dynamics of Flood Risk in the River Odra Basin on the Example of the Hydrological Station in Town Trestno

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    The aim of the article is to assess the variability of the floods’ risk with the use of maximal values distribution. In the authors’ researches, the hydrometric data in the form of daily water levels from the period of years 1981-2013 will be used. The collected data come from the hydrological station in town Trestno, located in the 242.1 km of Odra River (in southern-west Poland). For the purpose of estimating the flood risk, quarterly highs from the collected data have been selected. Authors have taken the probability of exceeding the alarm states for the analyzed section of the river as a measure of the risk of appearing floods. This risk has been calculated by using the theoretical cumulative distribution of quarterly highs of the water levels. The Frechet distribution was used in the studies as well. At the same time, the article has paid significant attention to the possibility of adapting the shown solutions for the integrated flood risk management process in accordance with the current National and European legislations

    DC Magnetic Properties of Amorphous Vitrovac Ribbon

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    Soft magnetic amorphous Co-based materials prepared by rapid quenching method in the form of thin ribbon are well-known due to their excellent soft magnetic properties as high permeability, low coercivity, and low magnetic losses in kHz range. The amorphous Co-Fe-B-Si material Vitrovac® 6155 U55 produced by Vacuumschmelze GmbH & Co. KG belongs to this class of materials and was investigated in as-delivered state. The aim of this work was to study DC magnetization process by various experimental methods. We have measured magnetization curve by fluxmeter based hysteresis graph and hysteresis loops by three different fluxmeter based hysteresis graphs, exhibiting significant differences. The first and the second hysteresis graph perform the hysteresis loops measurement by the point-by-point method, either with commutative or with summing steps. The third one is AC hysteresis graph working at very low frequencies down to 7 mHz, performing the continuous method. The explanation of this result is based on the structural after effect influencing the domain wall displacement. We assumed that the domain structure consists of very small number of domain walls responsible for magnetization process, which was confirmed by the visualization of static domain structure by a computer-controlled setup based on the Kerr effect

    Changes in elm (Ulmus) populations of mid-westernPolandduringthepast35years

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    Abstract: Three elm species are native to Poland: wych elm (Scots elm) (Ulmus glabra Huds.), field elm (U. minor Mill.), and European white elm (fluttering elm) (U. laevis Pall.). The epidemic of Dutch elm disease (DED) has led to a decrease in the popularity of elm cultivation. An analysis of forestry data was the first step in the assessment of elm resources. The area of forest stands where elms are dominant has more than doubled since 1978. Lowland alluvial forests rank first in regards to the number of elm localities per unit area of a given forest site type. While this site type is clearly preferred by elms, the majority of elm trees are actually scattered among sites of oak-hornbeam or closely related forests (of the alliance Carpinion betuli). Field research revealed a clear dominance of U. laevis, a species which in the past was predominantly located out of woodland and rarely cultivated. Data analysis indicated that all trees greater than 70 cm in diameter belonged to this species. Data from plots surveyed directly also suggest that the three elm species have slightly different habitat preferences. U. laevis prefers riparian habitats, although the major part of its resources is now on potential sites of oak-hornbeam or closely related forests. U. minor even more often than U. laevis occurs at less humid sites (mostly potential sites of oak-hornbeam or closely related forests), while U. glabra prefers moist slopes. In general, it appears that the impact of DED in the last 20-30 years has been smaller than in the preceding period, however, the disappearance of the disease has not been established. Undoubtedly, U. laevis is the elm species that is least impacted by DED

    Effect of pre-planting soil preparation on biological activity of soil towards root rot pathogens in 40-year-old Scots pine stand

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    Effects of pre−planting soil preparation on the clear−cut on the community structure of soil fungi and bacteria, their possible biological activity towards Armillaria and Heterobasidion, and mortality of Scots pine trees were studied in 40−year−old Scots pine plantation in Międzychód Forest District (W Poland). Pre−planting soil preparation included: (i) deep ploughing, (ii) shallow furrowing, (iii) making holes for planting, and (iv) shallow turning of the topsoil. The soil−dilution method was used for detection of fungi and bacteria in soil. Morphotyping was used for identification of fungi. Phenotypic traits and biochemical properties were used for identification of bacteria. Molecular method, MID−66 or BIOLOG® systems were additionally applied for identification of the most common bacteria. Deep furrowing, making holes for planting or shallow turning of the topsoil before planting increased abundance of fungi and bacteria in soil 40 years after treatment. Increased abundance of fungi and bacteria was associated with increased presence of taxa considered as antagonistic to Armillaria and Heterobasidion. The highest mortality of Scots pines was observed on sites with deep ploughing or shallow furrowing before planting, while the lowest mortality was found on sites with making holes for planting or shallow turning of the topsoil. The majority of dead trees were infected by H. annosum. Moderate intervention into the soil habitat on the clear−cut site before planting of Scots pine seedlings seems to create the habitat beneficial for the future growth of trees

    Deep Level Transient Spectroscopy Studies of CdMnTe

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    Deep levels in Ga doped n-type CdMnTe of 1% and 5% Mn contents and In doped n-type CdMnTe of 20% Mn content were studied using deep level transient spectroscopy technique. Our deep level transient spectroscopy results show presence of several groups of different traps

    SUR LE MINIMUM DE LA SECTION EFFICACE TOTALE DANS LA RÉGION DES NOYAUX ATOMIQUES AVEC A = 60 POUR DES PARTICULES ALPHA DE 24,7 MeV

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    La section efficace totale pour l'interaction des particules alpha à l'énergie 24,7 MeV avec les noyaux atomiques de Cr, Fe, Ni, Co, Cu et Zn a été mesurée à l'aide de la méthode de transmission. Les corrections aux résultats des mesures de la transmission pour la diffusion élastique et pour les particules chargées issues des réactions étaient déterminées dans les expériences effectuées spécialement. Les résultats pour les sections efficaces totales des réactions sont en accord avec les calculs faits à l'aide du modèle optique. Aucun minimum dans la courbe représentant les valeurs σR vers A n'a été observé pour les noyaux atomiques de nickel.The total reaction cross-section for the interaction of alpha particles of the energy of 24.7 MeV with Cr, Fe, Ni, Co, Cu, and Zn nuclei has been measured by means of the transmission method. The corrections to the transmission measurements for the elastic scattering and for the charged products of reactions have been determined from a specially performed experiment. The results for the total reaction cross-sections are in agreement with optical model calculations. No minimum in the σR versus A curve for the nickel atomic mass-numbers is observed

    Microarthropods Living on the Endemic Tree Zelkova abelicea (Ulmaceae) with Particular Attention to Collembola Diversity

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    Zelkova abelicea is an endemic tree species growing in several localities in the mountainous regions of Crete, Greece. To date, the microarthropod species associated with this tree species have not been identified. Since Z. abelicea populations are isolated and fragmented, it was hypothesized that the characteristics of microarthropod assemblages, particularly in the case of springtails (Collembola), would vary and differ among localities. Moreover, rare microarthropod species that colonize microhabitats not included in previous studies on Zelkova trees were expected to be recorded. Samples were collected from the bark and twigs of Z. abelicea at eight localities in all main mountain ranges. Among the collected material, Collembola were the most numerous (10,285), followed by Acari (2237) and representatives of Psocoptera (422). The obtained material and statistical analyses showed that the arthropod assemblages differed considerably at each experimental site, with the most distinct assemblage characteristics observed at the Gerakari site on Mt. Kedros in central Crete. The most numerous specimens were species of Collembola: Xenylla maritima (3844), Xenylla sp. 2 (maritima complex) (3364) and Xenylla sp. 1 (maritima complex) (2631). A total of 33 Collembola species were recorded, of which 19 had not been previously reported in Crete. Among them, 11 species were likely new to science and will be the subject of separate taxonomic studies
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