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On characteristics of stable boundary layer flow fields and their influence on wind turbine loadsPark, Jinkyoo 30 September 2011 (has links)
Fourier-based stochastic simulation of wind fields commonly used in wind turbine loads computations is unable to account for contrasting states of atmospheric stability. Flow fields in the stable boundary layer (SBL), for instance, have characteristics such as enhanced wind shear and veering wind direction profiles; the influence of such characteristics on utility-scale wind turbine loads has not been studied. To investigate these influences, we use large-eddy simulation (LES) to generate inflow wind fields and to estimate load statistics for a 5-MW wind turbine model. In the first part of this thesis, we describe a procedure employing LES to generate SBL wind fields for wind turbine load computations. In addition, we study how large-scale atmospheric conditions affect the characteristics of wind fields and turbine loads. Next, in the second part, we study the contrasting characteristics of LES-SBL and stochastic NBL flow fields and their influences on wind turbine load statistics by isolating effects of the mean wind (shear) profile and of variation in wind direction and turbulence levels over the rotor sept area.
Among large-scale atmospheric conditions, the geostrophic wind speed and surface cooling rate have the greatest influence on flow field characteristics and, thus, on wind turbine loads. Higher geostrophic winds lead to increased mean and standard deviation values of the longitudinal wind speed at hub height. Increased surface cooling rates lead to steeper shear profiles and appear to also increase fatigue damage associated with out-of-plane blade root moments. In summary, our studies suggest that LES may be effectively used to model wind fields in the SBL, to study characteristics of turbine-scale wind fields, and to assess turbine loads for conditions that are not typically examined in design standards. / text
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Vliv změny pravidel v roce 2010 na střelbu hráčů NBL / The effect of the rules change in 2010 on shooting of NBL playersSVOBODA, Václav January 2014 (has links)
The aim of our diploma thesis is to identify and evaluate the impact of rules changes in 2010 on success of two-point shooting and three-point shooting between selected Czech and foreign players taking part in National Basketball League who have met with our specified conditions in examined seasons 2009/10 and 2010/11. There are following methods used in the very research in the empirical part: Student´s paired t-test, Two-sample F-test, Student´s unpaired t-test of equality of variances and Size of effect. The results of these tests has statistically confirmed our hypotheses H1 and H2 it means decreasing of two-point shooting success in season 2010/11 for all examined players and reducing of success at three-point throws between players with Czech nationality. On the contrary, it has not confirmed the hypothesis H3, thus increasing of three-point shooting success in season 2010/11 between foreign players. Substantively, I consider as a essential result the 20,1% impact of the rules changes on success of three-point shooting for players of Czech nationality.
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Komparácia systémov odmeňovania rozhodcov v profesionálnych ligách / Comparison of systems of remuneration referees in the professional leaguesVansa, Miroslav January 2012 (has links)
This thesis, which is divided into theoretical and analytical part, deals with the analysis of the remuneration of referees in professional basketball leagues in the U.S. and Europe. Consequently, it compares and evaluates these systems. In the theoretical section first it explains the rules of basketball and its popularity in the world compared to other sports. It mentions here about the two most prestigious competitions of the world basketball - the NBA and Euroleague. Analytical section begins with an explanation of the functions and work of a basketball referees. There is also explained the process of how to become a basketball referee. After that, it analyzes the two options of their remuneration system on the example of Czech basketball league NBL and American league NBA. It also compares these different evaluation systems. Referees had a chance to say their opinion through interviews and questionnaires, which is summarized in the penultimate chapter of the analytical work. In the last chapter it presents a SWOT analysis of the American way of remuneration of arbitrators and the possibility of its application to the European competitions.
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Benford’s Law and its Ramifications, especially in the Context of COVID-19 Infections and DeathsGhaderian, Mostafa January 2021 (has links)
No description available.
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Paprastosios pušies (Pinus sylvestris L.) formos pagal žievės raštą Punios šile / Bark forms of Scots pine (Pinus sylvestris L.) in Punios ŠilasGražulevičius, Gintaras 15 June 2009 (has links)
Darbo objektas: Alytaus miškų urėdijos Punios girininkijos Punios šilas.
Darbo metodai: vizualinis žievės formų ir medžių būklės vertinimas; taksacinių rodiklių ir morfometrinių parametrų matavimai; pHCaCh2, suminių anglies, azoto ir sieros koncentracijų nustatymas.
Darbo rezultatai: nustatyta skirtingų žievės formų pušų įvairovė ir paplitimas, būklė ir augimas, morfologiniai ir morfometriniai bei cheminiai rodikliai. Rastos gūbriuotosios (40-70 proc), plokštelinės (27-31 proc), egliažievės (10-15 proc.) ir apykaklinės (pavienės) formų geros būklės pušys. Pušynuose 75-100 proc. gūbriuotųjų, plokštelinių ir apykaklinių pušų pušynuose priklausė viršaujantiems ir vyraujantiems medžiams. Apie 60 proc. egliažievių pušų medžių arde buvo stelbiamos ar užstelbtos. Todėl gūbriuotųjų, plokštelinių ir apykaklinių pušų augimo rodikliai (skersmuo, aukštis, lajos parametrai) iš esmės nesiskyrė, o pas egliažievės pušis buvo mažesni. Gamtinės brandos amžiuje pušies formos pagal žievės raštą būna išreikštos vidutiniškai iki 10-12 m aukščio nuo žemės paviršiaus. Gūbriuotosios ir egliažievės f. vidutinis žievės storis siekė 5 cm, plokštelinės - apie 4 cm. Žiauberyje storiausios (apie 3 cm) plokštelės būdingos gūbriuotajai pušiai, plonesnės (1,5 cm) - gūbriuotosioms, o ploniausia (apie 1 cm) - egliažievėms pušims. Pas egliažievės pušis plokštelių vidutinis ilgis (aukštis) siekė 5 cm, plokštelinėje žievėje - 19 cm, o gūbriuotoje - 28 cm ilgį. Apykaklinės f. pušyse apykaklės gali susiformuoti... [toliau žr. visą tekstą] / The aim of the study: to evaluate the morphological forms of Scots pine bark, the abundance, growth and the condition of trees with different bark forms, morphological, morfometrical and chemical parameters of bark forms.
The object of the study: Punios šilas in Punios forest district of Alytus forest enterpsise.
Methods: visual assessment of different bark forms and the condition of pine trees; measurements of tree growth parameters and the parameters of morphological bark forms; determination of pH and carbon, nitrogen and sulphur concentrations.
The results: It was determined that 3 forms prevailed in Scots pine stands: P. s. f. kienitzii Seitz. – 40-70%; P. s. f. seitzii Schwerin – 27-31%; P. s. f. bonapartei – 10-15%. Meanwhile P. s. f. annulata Caspary occurred seldom only on Nbl forest site. The growth and the condition of the trees of f. kienitzii and f. seitzii not differed, while the trees of f. bonapartei were more suppressed. Mentioned bark forms were expressed up to 10-12 meters from the ground level in pine stems. Mean bark thickness comprised 5 cm for f. kienitzii and f. bonapartei, and 4 cm for f. seitzii. The thickest bark plates were found in the f. kienitzii (about 3 cm), meanwhile were lower in f. seitzii (1.5 cm) and f. bonapartei (1 cm). Mean length of the bark plates comprised: in f. bonapartei – 5 cm; in f. seitzii – 19 cm; in f. kienitzii – 28 cm. The number of the bark rings reached n=5-21 in the stems of f. annulata. The bark of different forms... [to full text]
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Národnostní struktura hráčů extraligy mužů v basketbalu od roku 1998 a její dopad na basketbal v České republice\\ / The national structure of players of Czech national basketball league since year 1998 and its impact on basketball in the Czech Republic\\BUBÁK, Jiří January 2010 (has links)
The diploma thesis studies the evolution of the national structure of players in the highest Czech basketball league, the `Extraliga{\crq}, between seasons 1998/1999 and 2008/2009. This research is based on analysis of technical registers from individual games. The author splits the studied sample of players into three groups (Czech players aged 20+, foreign players and Czech players below 20 years of age) and evaluates statistical characteristics by virtue of the comparative method. These include the number of players, minutes played, points scored and a coefficient of usefulness. The results confirm the expected increase of the number of foreign players as well as their continuously growing impact on the game. In contrast to this, the trend of participation and usefulness of Czech players under 20 years is shown to be diminishing. Both the hypotheses of the thesis are therefore proven valid. The presented work further utilizes the analysis of references in several directions, namely it points to existing basketball youth centres in the Czech Republic, warns against the diminishing member base of this sport, highlights the change in trend of evolution of imposed limits on the number of foreign players in Extraliga and finally discusses some of the current issues of Czech basketball.
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DNA Origami Mechanisms and MachinesMarras, Alexander Edison 25 July 2013 (has links)
No description available.
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