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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
751

Zastřešení atletické haly / Roofing of Athletic Hall

Potůčková, Simona Unknown Date (has links)
The aim of this diploma thesis is a design of two versions of bearing roof construction of the athletic stadium in Brno and a smaller side roofing of changing rooms. The building has rectangular plan of dimension 67 x 102 m and the side construction has also rectangular plan of dimension 61x 8 m. The minimum height is given by requirements of various athletic sports. Material used for the main construction is steel strength class S355 and for the side construction it is steel strength class S235. All the calculations are according to valid norms ČSN EN.
752

Obecný bilanční srážko-odtokový model povodí / General Runoff Water Balance Model of a River Basin

Černý, Vojtěch Unknown Date (has links)
Modelling of the rainfall-runoff process is one of the basic scientific skills in hydrology. Rainfall-runoff modelling can help to improve water management, handling of the reservoir's storage volume, or also to facilitate adaptation to current climatic conditions. The aim of the diploma thesis is to create a functional rainfall-runoff model on the basis of water balance equations based on the lumped water balance principle of the hydrological model. Several modifications of the general rainfall-runoff model are approached in the diploma thesis. Four types of the daily evapotranspiration determination are used in the calculations. The rainfall-runoff model is compiled from temperature data and precipitation totals in a daily step. The practical application is carried out on a sub-basin of the river Dyje, which is located above Vranov water reservoir. The main output is a series of daily flow rates that were obtained from calibrated rainfall-runoff models. The best rainfall-runoff model takes into account the water from snow cover melting, the value of the Nash Sutcliffe calibration criterion of this model is 0.608. Finally, the hydrological simulation for the period 2021-2060 is performed in the diploma thesis.
753

Odtok ze sněhu při událostech deště na sníh v povodí Ptačího potoka vypočtený pomocí stabilních izotopů ve vodě / Snowmelt runoff during rain-on-snow events in the Ptačí brook basin calculated using stable water isotopes

Valdhansová, Klára January 2020 (has links)
Rain-on-snow events represent one of the basic mechanisms causing floods. Rain falling on the snow cover causes enhanced melting and the resulting runoff often exceeds the runoff caused by rain. During the winter seasons 2018 and 2019, water samples from the stream, snowpack and precipitation were repeatedly taken in the the Ptačí Brook catchment in the Šumava mountains, and the concentrations of 2 H and 18 O were measured in the laboratory. Based on the observed isotope ratios 18 O/16 O and 2 H/1 H in combination with other variables measured in the catchment, the two ROS events from 2019 were reconstructed. The ratio of heavy isotopes increased in the snowpack due to ROS events. Using the end member mixing equation, a hydrograph separation was performed for both investigated events. For the first event, it was not possible to clearly separate groundwater from rainfall, and thus the range of snow in the total runoff was determined by its separation from rainfall and subsequent separation from groundwater. The second event examined was separated directly into three components: rainfall, groundwater and snow. According to the analyses, the total runoff during ROS events in both cases was mostly formed by event water (a combination of rainfall and melt water). The melting water from the snow cover...
754

Autorská muzikálová pohádka z pohledu hudební výchovy / Author's Fairy Tale Musical from the Perspektive of Educating Music

Dejlová, Hana January 2020 (has links)
This thesis introduces two author's fairy tale musicals called Snow White and Cinderella. These musicals are intended for the early and late school-aged children. To understand the broader context and to provide for more information about this particular genre, the theoretical part discusses how musicals as a musical genre was created and then, it discusses its development, changes, forms and main features. It provides the information about the development of musicals in both the Czech Republic and abroad. Then, it elaborates on the professional musicals production for children (being the performers), again both abroad and in the Czech Republic. This is then followed by a practical part that introduces the two pieces mentioned above. It presents the information about their creation, realisation and motivation. In addition, it presents a critical analysis of their appropriateness for the child performers in light of their musical skills, abilities and the specifics of this age group while focusing on the music components of these pieces, such as melodic and harmonic aspects of the musicals, any key issues and issues of the transition from one key to another, rhythm, tempo changes and any challenges given by the dramatic expression and ability to speak other languages. The analysis was performed...
755

Samhällsekonomiska effekter av vinterväghållning för gående. : En kostnads- nyttoanalys av vinterväghållning och gångtrafikanters singelolyckor i Stockholms stad. / Socioeconomic impacts of winter maintenance for pedestrian. : A cost benefit analysis of injuries in single-pedestrian accidents and road maintenance in the city of Stockholm.

Mattsson, Angelina January 2017 (has links)
Gångtrafikanters singelolyckor är Stockholms i särklass vanligaste trafikolycka och bland orsakerna till olyckorna beror en majoritet på dålig snöröjning eller halkbekämpning. Kommunen antar därför att samhällskostnaderna är höga och för att kunna prioritera vinterväghållningen behöver anmälningar om halkolyckor studeras samt jämföras med olycksstatistiken. Syftet med arbetet är att beskriva ett tillvägagångssätt för att genomföra en samhällsekonomisk analys av vinterväghållning för gångtrafikanter. En kostnads-nyttoanalys illustrerar en metod för att utvärdera och analysera vinterväghållning ur ett samhällsperspektiv. Kostnads-nyttoanalysen appliceras på vinterväghållning i Stockholms stad och vidare diskuteras metodens utmaningar och möjligheter för ändamålet. Metoden är även applicerbar på andra kommuner i Sverige och organisationer som står inför likande problem och bidrar således med ett viktigt verktyg för beslutsfattare. Resultatet av kostnads-nyttoanalysen visar att gångtrafikanters situation i Stockholm sannolikt skulle gynnas av en förbättring. En generell satsning på vinterväghållning innebär en ökad nytta för gångtrafikanterna under antagandet att antal olyckor minskas. Nollalternativet visar att den samhällsekonomiska kostnaden för olyckor är betydligt högre än vinterväghållnings-kostnaderna i nuläget. Kostnads-nyttoanalysen är ett exempel på hur Stockholms stad kan lägga ett helhetsperspektiv på planering av drift och underhåll av gångytor. För att möjliggöra uppföljning och utvärdering av hur resurser används behövs mer specifikt bättre verktyg för rapportering av drift och underhåll.
756

Montagekvalité av solcellsinstallationer i Mellansverige : En utvärdering av hållfasthet för installerade solcellsanläggningar

Nyman, Joar January 2020 (has links)
Antal installerade solcellsanläggningar har ökat drastiskt de senaste åren i Sverige, och utsikten för ökad mängd solel i Sverige är mycket god, med prognoser på kraftig tillväxt av installerade solcellsanläggningar de kommande åren. Detta med bakgrund att utvecklingen av solcellspaneler har gjort att priset har sjunkit, samt politiska beslut har gjort det lönsamt att investera i solcellsanläggningar i Sverige. Dessa förutsättningar har lagt grunden för en ny växande bransch, solcellsinstallationer. Risken vid en ny och snabbt växande bransch är att kunskapen inom ämnet för de som är verksamma inom branschen kan vara bristfällig samt oseriösa företag kan lockas av att tjäna snabba pengar på en lukrativ marknad. Efter en omfattande litteraturstudie visades att någon större kvalitésundersökning av solcellsinstallationer i Sverige, med avseende på hållfasthet ej har gjorts tidigare. Detta motiverade att denna undersökning var av hög relevans. Syftet med denna studie var att ta reda på om solcellsanläggningar monteras tillräckligt hållfast i Gävle-Dalaregionen med avseende på snö- och vindlast. Fjorton anläggningar har besökts för att samla in data. Data har sedan utvärderats i tre kategorier per anläggning. För att en anläggning skall bedömas som en godkänd skall alla dessa tre kategorier vara godkända. Bedömningen av solcellsanläggningarna gjordes i de tre kategorierna: 1. montagesystemets antal infästningar, 2. mått mellan infästningarna, 3. placering av solcellspanelerna i förhållande till montagesystemet. Resultatet visade att ingen av dessa anläggningar var godkända i samtliga tre kategorier. Vissa anläggningar var godkända i två av tre kategorier, medan två anläggningar var ej godkänd i någon kategori. Vid en summering av bedömningsresultatet för alla anläggningar i de tre montagekategorierna, visades att ca 20% ej gick att fastställa (pga. bristande information) ca 40% var godkända och ca 40% var ej godkända. Bedömningar har gjorts utifrån beräkningsprogram och anvisningar tillhandahållna av tillverkarna av de montagesystem och solcellspaneler som har använts i anläggningarna. Att ingen anläggning var godkänd i samtliga tre kategorier som undersöktes indikerar att solcellsmontage på tegeltak byggs ej tillräckligt hållfast i Gävle-Dalaregionen. Detta kan dock inte generaliseras för solcellsanläggningar på tegeltak i hela Sverige då mängden undersökta anläggningar var relativt liten och endast fördelade på två län i landet. Då det antas att installatörer avser att bygga korrekta anläggningar visar denna studie att kunskap om solcellsmontage med avseende på hållfasthet är bristfällig. Detta kan vara en följd av den stora efterfrågan på solcellsinstallationer, som kan medföra att stort fokus ligger på att installera anläggningar snabbt, och inhämtning av kunskap ej blir prioriterat. / The number of installed PV-systems (Photovoltaic systems) has increased rapidly in Sweden the last years, and the forecast for even more installations shows an increase for the coming years. Due to the price for PV-panels har dropped and political decisions for subventions of PV-systems has made it more profitable to invest in PV-installations in Sweden. These reasons have paved the road for a new growing branch, PV-installations. The risk of a new profitable, fast growing branch is that there might be short of knowledge for new installers, and the possibility that dishonest companies just want to take the advantage of the situation to make quick money, which can lead to installations poorly made.   After a search of published literature in strength of mounting for PV-panels there the result was that this is a rather unexplored subject, which motivated this investigation.   The aim of this study was to find out if PV-panels on tiled roofs were installed correct due to the snow load and wind load in the region Dalarna and Gävleborg in Sweden.   Fourteen PV-systems has been studied and evaluated. When the evaluation of the PV-systems were made the following criteria were considered: number of fixing attached to the roof of the mounting, distance between mounting fixings and how the PV-panels were installed relative the construction of the mounting. A PV-system had to be installed correctly for all three criterias to be considered approved. The result of this work shows that none of the evaluated systems were installed correctly. Some systems were approved in two of the criteria, while two systems were not approved in any of the criteria. The evaluation was made due to calculation programs and instructions from the manufacturers of mounting and PV-panels.   The fact that none of the PV-systems were approved for all three criteria implies that the installations of PV-systems are not made strong enough. This result is not stated for all installations in Sweden because the number of studied PV-systems were not big enough, and the area of the studied installations were rather small. Basis of snow load and wind load variates quite much in Sweden depending on region. It is assumed that designers and constructors attempt to install PV-systems correct, therefor shows this work that there’s a lack of knowledge for construct installations strong enough. This may be a result of the fast increase of PV-installations, where the priority lays in installing many PV-systems, not in education and search of knowledge.
757

Beräkningsmall för vind- och snölast enligt Eurokoderna : Jämförelse mellan Stomstabiliseringssystem av en industribyggnad / Calculation model for wind- and snow load according to Eurocode : Comparison of lateral stability system in an industrial building

Klinga, Niloofar, Selvad, Tomas January 2015 (has links)
Examensarbetet kom som en förfrågan från företaget Northpower stålhallar AB som var i behov av en beräkningsmall för vind- och snölast. Beräkningsmallen utformas i Microsoft Excel och den ska möta de önskemål och krav som tillkommer vid projektering av en hallbyggnad. Beräkningsmallen grundas på en litteraturstudie av vind- och snölast kapitlen i Eurokoderna som inleder den teoretiska delen av rapporten. För att se skillnader mellan stomstabiliseringssystem som vanligen används i hallbyggnader, utfördes en litteraturstudie på vanligt förekommande systemen. En kraftanalys vid olika placeringar av företagets nuvarande stomstabiliseringssystem gjordes med hjälp av den tillverkade beräkningsmallen. Litteraturstudien och analysen sammanställdes till jämförelse av de olika stomstabiliseringssystemen. / The subject of this bachelor thesis was a query from Northpower stålhallar AB that was in need of a calculation model for wind- and snow loads. The Calculation model was created in Microsoft Excel and shall satisfy the requirements for the design of an industrial building. The calculation model is founded on a literature study of Eurocodes wind- and snow load chapters, which initializes the theoretical part of the report. To gain a better understanding of the differences between the different types of bracing systems that is normally used in industrial buildings, we performed a literature study on a selection of the usual systems.  Using the calculation model, a force analysis on different placing’s of the current lateral stability system the company use was carried out. The thesis ends with a comparison of the study and analysis of the different lateral stability systems that’s been studied.
758

Land surface heat exchange over snow and frozen soil

Gustafsson, David January 2001 (has links)
The energy exchange in the soil-snow-vegetation-atmospheresystem was studied to improve the quantitative knowledge of thegoverning processes. The lack of such knowledge contributes tothe uncertainty in the applicability of many existing modelsindependent of the temporal or spatial scale. The theoreticalbackground and available methods for measurements and numericalsimulations were reviewed. Numerical simulation models andavailable data sets representing open land and boreal forestwere evaluated in both diurnal and seasonal time-scales.Surface heat fluxes, snow depth, soil temperatures andmeteorological conditions were measured at an agriculturalfield in central Sweden over two winters, 1997-1999. Twoone-dimensional simulation models of different complexity wereused to simulate the heat and water transfer in thesoil-snow-atmosphere system and compared with the measurements.Comparison of simulated and observed heat fluxes showed thatparameter values governing the upper boundary condition weremore important than the formulation of the internal mass andheat balance of the snow cover. The models were useful toevaluate the lack of energy balance closure in the observedsurface heat fluxes, which underlined the importance ofimproved accuracy in eddy correlation measurements of latentflow during winter conditions. The representation of boreal forest in the land surfacescheme used within a weather forecast model was tested with athree-year data set from the NOPEX forest site in centralSweden. The formulation with separate energy balances forvegetation and the soil/snow beneath tree cover improvedsimulation of the seasonal and diurnal variations of latent andsensible heat flux compared with an older model version.Further improvements of simulated surface heat fluxes could beexpected if the variation of vegetation properties within andbetween years and a new formulation of the boundary conditionsfor heat flux into the soil is included. Keywords: Surface energy balance, Snow, Boreal forest,SVAT models, Eddy-correlation Measurements, Latent heat flux,Sensible heat flux, Net radiation, Soil temperature,Aerodynamic roughness, Surface resistance / QC 20100614
759

Time series analysis of ground frost conditions at Abisko, sub-Arctic Sweden, 1985-2010 / Tidserieanalys av marktemperatur i Abisko,Norra Sverige, under perioden 1985-2010

Schmidt, Anja January 2012 (has links)
Observed climatic change may result in modification of the ground thermal regime.The causes of shallow ground temperature variability, however, are not well documented.This thesis reports ground temperatures from Absiko Scientific Research Station, measured ata site currently not underlain by permafrost to illustrate the response of shallow groundtemperatures to changes in climatic parameters. Both air temperature and precipitationincreased at Abisko from 1985-2010. The strongest increase in air temperature occurred inwinter, whereas the precipitation increased mainly during the summer months. There was asignificant trend towards later onset of permanent snow cover, as well as a steadily earlierdisappearance of permanent snow cover in spring, resulting in reduced snow cover duration.Also the snow thickness decreased at Abisko during the study period. The ground experiencedapproximately five months of frost at 5 and 20 cm depth and approx. four, respectively two,months at 50 and 100 cm depth. Annual ground temperatures were found to be increasingfrom 1985-2010 with approx. 0.31 °C, 0.64 °C, 0.82 °C and 0.94 °C at 5, 20, 50, respectively100 cm depth from the surface. The duration and intensity of the seasonal frost cycles weredecreasing, which would reflect the increasing ground temperatures. Changes in short-termfrost cycles were not found to be significant. The changes in mean annual and winter groundtemperature were significantly correlated to the changes in mean annual and winter airtemperature, but surprisingly not to the changes in snow cover. However, seasonally theincreasing trend of ground temperatures was found in autumn and winter, whereas thesummer ground temperatures were decreasing. The cooling of ground temperature in summerat increasing air temperatures may be explained by increased precipitation totals and henceincreased soil moisture due to the so called soil-moisture feedback. From this fact, it can bededuced that the changes in air temperature alone cannot explain all variances in groundtemperatures. However, the results of the study may suggest that in sub-Arctic Swedenchanges in air temperatures may be used as indicator for changes in shallow groundtemperatures. / perioden 1985-2010 ökade både lufttemperatur och nederbörd i Abiskoområdet. Denstörsta ökningen av lufttemperatur skedde under vinterhalvåret medan nederbörden ökademest under sommarhalvåret. En signifikant förkortning i längden av vintersnötäckets existensunder året observerades under studieperioden. Reduceringen av vintesnötäcket skedde genomatt den första snön kom senare och bortsmältningen på våren skedde tidigare. Snötäcketstjocklek minskade också under studieperioden. Marktemperaturmätningarna visar frysgraderpå 5 och 20 cm djup fem månader och fyra respektive två månader på 50 och 100cm djup.Den årliga medeltemperaturen i marken ökade under perioden med 0.31 °C, 0.64 °C, 0.82 °Coch 0.94 °C vid 5, 20, 50 och 100 cm djup. Den årliga längden och intensiteten avfrysförhållandena i marken minskade vilket förmodligen är en konsekvens av de ökandemarktemperaturerna. Ingen trend i förekomsten av kortare svängningar i frysförhållandenakunde observeras. Förändringarna i årsmedetemperaturen i marken är signifikant korrelerademed förändringen i den årliga medeltemperaturen och vintertemperaturen i luften, men ingenkorrelation mellan marktemperaturen och förändringar i snötäckets tjocklek och längdobserverades. Studien avslöjade också att temperaturen i marken ökade under vinternhalvåretmedan den sjönk under sommaren. Avkylningen av marken under sommaren kan förklaras avökad nederbörd under sommaren som ger högre markfuktighet som ger en kylande effektgenom den så kallade jord-fuktighets återkopplingsmekanismen (soil-moisture feedback).Från detta kan vi dra slutsatsen att förändringar i enbart lufttemperatur inte kan förklara denhela observerade variansen av marktemperatur men att lufttemperaturen har en domineranderoll. Resultaten från denna studie indikerar således att förändringar lufttemperatur kananvändas som en indikator på marktemperaturförändringar i Abisko området.
760

Clear-cut Effects on Snow Accumulation and Evapotranspiration in a Boreal Catchment in Northern Sweden / Avverkningseffekter på snöackumulation och evapotranspiration i ett nordligt avrinningsområde i Sverige

Rudling, Mikaela January 2013 (has links)
The aim of this thesis was to investigate the processes behind an unexpected runoff behaviour after a clear-cut in a boreal forest in northern Sweden (Balsjö). The risks of increased flooding, erosion, nutrient leakage and changes in the local ecosystems are some reasons why it is important to fully understand the effect of clear-cuts on the water balance. In northern boreal forests the snow is of great importance as it results in the main hydrological event of the year, the spring flood. In general, open areas accumulate more snow, have a lower evapotranspiration and therefore maintain a higher runoff than a forest. In a recent paired catchment study at Balsjö the expected pattern after a clear-cut was only shown in three out of five years (2007-2011). The expected increase in runoff did not occur in 2010 and 2011. Two hypothesized alternatives were year-to-year variation of ET or changes in soil water storage. In order to investigate this further the rainfall-runoff model HBV was used. First, the model was calibrated for the forest catchment (Ref) and the clear-cut catchment (CC), using observed data from Balsjö. To account for parameter uncertainty the calibration was performed using parameter optimization, resulting in 100 different parameter sets. Model results were evaluated using observed snow data from Balsjö and ET from Flakaliden, a nearby forest. Both the simulated snow and ET were quite consistent with the observed values. Finally the annual and the spring water balance were studied, using the simulated data. The simulated results did not detect the unexpected runoff behavior for the two years as clearly as the observations. The reason for this was that the model was calibrated for all five years, which meant that annual variations were not taken into account. The hypothesis, that higher ET could be the reason for the unexpected runoff behavior, could neither be dismissed nor confirmed by this thesis. This was because there were no observed data for the clear-cut area and limitations within the HBV model, which meant that sublimation and interception processes could not be analyzed separately. The model results indicated that the change in soil water storage was a more likely explanation for the unexpected runoff behavior. The simulation result showed that the meltwater was stored in the soil water storage. However, this theory does not seem likely since a clear-cut is normally wetter than a forest. The results of this thesis are consistent with other studies as they indicate that clear-cut effects should be studied seasonally as well as annually. The special feature of this thesis was the opportunity to study observed ET and investigate its influence on the water balance.

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