1,720,956 research outputs found
Estimation of the sediment transport based on volume of sediment retained by check dams
No full textRečni transport materiala je proces, ki je stalno prisoten v vodotokih. Prisotnost tega procesa je posledica energije vodnega toka, pa tudi erozije, ki predstavlja vir materiala, ki se premešča v vodotokih. Prisotnost plavin v vodotoku vpliva na spreminjanje njegovih lastnosti in oblike, njihove posledice se na primer kažejo v spremembah rečne struge in pokrajine ter zapolnjevanju akumulacijskih pregrad. Poznavanje količin transporta materiala v vodotoku ima tako pomembno vlogo pri razumevanju naravnih procesov v vodotoku.
V diplomski nalogi obravnavamo dinamiko premeščanja sedimentov v hudournikih na območju Save Dolinke. Na podlagi zapolnjenosti in projektnih volumnov zaplavnih pregrad na hudourniških pritokih Save Dolinke skušamo oceniti količine materiala, ki se premeščajo v strugah teh hudournikov. S pomočjo primerjave lastnosti prispevnih območij vodotokov s premeščanjem sedimentov v njih skušamo ugotoviti kateri dejavniki imajo največji vpliv na količino transporta sedimentov v strugah hudournikov.
Cilj diplomske naloge je nadgraditi razumevanje dinamike transporta sedimentov in določiti bilance transporta sedimentov za posamezne pritoke Save Dolinke, ter ugotoviti kateri dejavniki imajo na transport sedimentov največji vpliv. Na podlagi analize v diplomski nalogi je ocenjeno, da se v strugah hudourniških vodotokov na območju Save Dolinke letno povprečno premesti 547 m3 rinjenih plavin oziroma 2,15 m3 rinjenih plavin na hektar prispevnega območja. Po ugotovitvah diplomske naloge imajo na transport sedimentov najizrazitejši vpliv lastnosti padavin in njihova erozivnost, ter pokrovnost tal.River transport of material is a process that is constantly present in watercourses. Its presence is due to the energy of the water flow, as well as erosion. The presence of sediments in the watercourse changes its characteristics and shape, which can be seen in changes of the riverbed and landscape. Knowledge about the amount of sediment transport in a watercourse has an important role in understanding its natural processes.
In the graduation thesis, we discuss the dynamics of sediment transport in torrents located in Sava Dolinka river catchment. Based on the volume of retained sediments and design volumes of check dams, we try to estimate the quantities of material that is transported by these torrents. By comparing the properties of watercourses’ drainage catchments with the transport of sediments in them, we try to determine which factors impact the rate of sediment transport.
The aim of the graduation thesis is to improve the understanding of sediment transport dynamics and to determine transport rates for individual torrents, as well as investigation which factors have the greatest impact on the sediment transport.
Based on the analysis conducted in the scope of the thesis, it is estimated, that an average of 547 m3 of sediments or 2,15 m3/ha of catchment area are transported annually in the torrents located in this territory. The erosivity of the precipitation and soil cover are indicated as two most dominant factors
Sediment transport modelling in the Sava Dolinka River
No full textV okviru magistrske naloge je obravnavana tematika modeliranja transporta (rinjenih) plavin. Predstavljene so teoretične osnove, potrebne za celovito obravnavo, pod kar spadajo tako določitev dotoka plavin iz zaledja, kot tudi lastnosti premeščanja plavin znotraj struge vodotoka. Pri prvi so predstavljene metode določitve potencialnega sproščanja sedimentov v zaledjih, pri drugi pa osnove o začetku prodnega premika, lastnostih različnih tipov premeščanja plavin in o različnih metodah določitve transportne zmogljivosti oz. količine premeščanja plavin v vodotoku. Premeščanje plavin je v nalogi obravnavano na konkretnem primeru Save Dolinke, ki predstavlja tipičen prodonosni vodotok. Obravnavan je bil odsek med sotočjem s Pišnico (Kranjska Gora) in prodnim zadrževalnikom Hrušica. Za omenjeni odsek je bil vzpostavljen enodimenzijski hidravlični model, dodatno prilagojen za modeliranje transporta sedimentov. Z njegovo uporabo je bila analizirana dinamika premeščanja rinjenih plavin na obravnavanem odseku. Dodatno je bil ocenjen vpliv lastnosti vodotoka (vodnatost, hrapavost podlage in zrnavost podlage), kot tudi nastavitev hidravličnega modela (izbira transportne funkcije itd.) na rezultate modeliranja transporta plavin. V zaključkih so na podlagi ugotovljenega vpliva posameznih parametrov podane smernice, ki določajo, čemu je pri modeliranju transporta potrebno posvetiti največ pozornosti, da bi zagotovili čim manjšo negotovost rezultatov. Predstavljene so prednosti in slabosti uporabljene metode modeliranja, ugotovljene tekom izdelave magistrske naloge. Na podlagi tega je bila posledično ocenjena njena uporabnost v različnih primerih.Within the Master\u27s thesis, we discuss the topic of modelling the transport of bedload sediments. We present the theoretical bases, which includes determination of sediment inflow from the hinterland, as well as the characteristics of sediment transport within the watercourse bed. Determination of sediment inflow wise, we describe the methods for determination of potential erosion of sediments in the hinterland. In the case of sediment transport within the riverbed, we introduce the basics of the start of bed load transport, the characteristics of different types of sediment transport as well as different methods of determining the transport capacity and the amount of sediment transport in the watercourse. In the thesis, the bed load transport is discussed on the concrete example of the Sava Dolinka river, which represents a typical gravel bed river. We focused on the section between the confluence with Pišnica (Kranjska Gora) and the dam Hrušica. A one-dimensional hydraulic model was established for the aforementioned section, additionally adapted for sediment transport modelling. It was used to analyse the dynamics of the bedload transport in this section. In addition, we evaluate the influence of watercourse qualities (water amount, roughness and grain size distribution), as well as hydraulic model settings (choice of transport function, etc.) on bed load transport modelling results. In the end, based on the established impact of individual parameters, we provide guidelines that highlight the priorities that should be given the most attention in bed load transport modelling in order to ensure the low uncertainty of the modelling results. The advantages and disadvantages of the applied modelling methods, established during the preparation of the Master\u27s thesis, are presented. Based on this, their usefulness in various cases was assessed
An analysis and comparison of business performance of municipalities: case of municipalities of Gorenja vas - Poljane and Žiri
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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