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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.
301

“Hon pratar som en svensk, en assimilerad invandrare” : En kvalitativ studie om kvinnors identitet i förorter / “She talks like a Swede, I assume an assimilated immigrant”

Noura, Emma, Bekir, Zeyneb January 2020 (has links)
Bakgrund: Kvinnors identitet i förorter Syfte: Uppsatsens syfte är att studera hur kvinnor i förorten utformar identiteter i spänningsfältet mellan olika identitetserbjudanden och hur kvinnor förhåller sig till dessa identitetserbjudanden. Metod: En kvalitativ studie har genomförts utifrån fokusgruppsintervjuer där vi har lyssnat på respondenternas personliga upplevelser. Sammantaget deltog 4 kvinnliga respondenter i åldern 22-45 år som sedan analyserades. Resultat: Studiens resultat vittnar om att respondenterna delar gemensamma åsikter kring utanförskapet som existerar i deras respektive bostadsområde. Kvinnorna nämner kontinuerliga anpassningar som behöver tas ställning till när de befinner sig utanför förorten. Respondenterna delar också uppfattningen att utseende och bostadsområdet (förorten) begränsar handlingsutrymmet exempelvis när de söker arbete. Kvinnorna antyder även att omgivningen och miljön är företeelser som begränsar och reglerar möjligheten att utforma den egna identiteten.
302

Mapping glacier change in Sweden between the end of ‘Little Ice Age’ and 2008 with orthophotos and a Digital Elevation Model

Hamré, Moa January 2015 (has links)
No description available.
303

Höjdmodellering med laserdata : Studie av Kärsön, Ekerö med fokus på upplösning, datalagring samt programvara

Löfquist, Johanna January 2012 (has links)
The New National Elevation Model (NNH) is a new high-resolution digital elevation model (DEM) of Sweden from airborne laser scanning. It creates many new opportunities, particularly in the area of flood mapping. NNH is provided by Lantmäteriet in two formats, both in raw LIDAR (Light Detection and Ranging) data and in grid format with two meter resolution. These alternatives have advantages and disadvantages and the aim of this thesis research is to identify these. One of the focuses of the study is data storage and thus data structure analysis, resolution and storage facilities. The research questions are: Why and in what context the different NNH-products from the National Land Survey are used (DEM 2+ or point cloud)? What constraints and opportunities are created by the different options, mainly in terms of different software, resolution, and data storage? The study area is Kärsön in Ekerö municipality located in Stockholms län and has an approximate area of 25 square kilometers. The study is divided into two parts. The first objective is to identify the consequences of using different software to create DEM from pointcloud compared to the DEM2+ model. Height models with a two meter resolution are created in FME and ArcGIS. The models are then compared with the grid from Lantmäteriet, created in TerraScan. The second objective is to examine the impact of the change in resolution, both the storage aspect and both the accuracy aspect. Inverse Distance Weighted (IDW) is an interpolation method which in previous studies proved to have the best results on high resolution LIDAR data. This model was tested and compared with a model from FMEs built-in function and the model from Lantmäteriet wich are based on triangulation (also proved a good method in previous studies).  The grid created in TerraScan has good properties such as accuracy. The results show that the built-in ArcGIS model is not sufficient for the purposes of the model. Flood mapping requires continuous surfaces and the model lacks large areas of data. However, there are other aspects such as the break lines, these cannot be added to the TerraScan model or in the IDW but in the FME-modeler it is possible. In addition, it is not possible to edit the model that is delivered from Lantmäteriet. If there are outliers in the data, they will have much impact on the result. With a model created from the point cloud it is easy to remove these outliers. Increased resolution gives a quadratic increase in storage space so it is considered important not to use a resolution that is not really necessary.  If the purpose of the analysis requires higher resolution than two meters it is possible to achieve higher accuracy for areas with high point density. The raw data format also provides opportunities to create additional models with other uses, building models or forest inventory application can for example be extracted from the data. If the purpose is that the finished grid model is adequate, there is no direct reason to spend time creating a new model. But for a user with knowledge of laser data structure and processing, creating elevation models from raw LIDAR data could give advantages.
304

Modeling Biomass Transport in a Compression Screw Feeder

Nathaniel Hall Gasteyer (9234404) 12 August 2020 (has links)
<p>Biorefineries which seek to convert biomass into ethanol face many different challenges, and among them, mechanical failure of equipment is common. Unfortunately, the resulting downtime can significantly reduce the profitability and the viability of bioethanol plants. One important piece of mechanical equipment in this setting is the compression screw feeder, which is used both to convey and compress biomass into pressurized chemical reactors. However, due to the variability of feedstock properties, this feeding operation is challenging. An analytical model for predicting the operational steady-state torque of a compression screw feeder can assist the identification of optimal processing conditions, as well as predict and prevent equipment failure.<br></p> <p>Since these models have not yet been proposed, this thesis restricts attention to milled corn stover and investigates the application of the discrete element method (DEM) and analytical techniques to develop predictive models for the stresses and torques developed inside a compression screw feeder. Specifically, DEM simulations are used to identify and study the stresses within the different sections of a representative compression screw feeder for three backpressures, three screw pitches, and three internal friction angles. Using these numerical results, a suite of analytical models is then developed to predict the operational torque required to drive the screw feeder. In this thesis, the DEM results are also used in lieu of experimental data to provide a point of comparison for the models.</p> <p>The analytical models predict stresses on the correct order of magnitude and are not prohibitively sensitive to input properties, but the operational steady-state torque is overpredicted by the model in all cases. The mispredictions of the model are likely due to the assumption of constant material properties along the densification process, and the assumption of hydrostatic conditions throughout the compression screw feeder (especially near the boundaries). Despite these limiting assumptions, the proposed procedure for calculating the torque provides a first-order estimate of the required screw torque, demonstrates the sensitivity of the screw feeder to different inputs, and outlines the necessary steps to improve the model. The DEM simulations proved an invaluable tool in analyzing the behavior of bulk material within a compression screw feeder, but more experiments and simulations (possibly using the finite element method) are needed to further understand the biomass feeding operation.</p>
305

Pandemiberedskap: handhygien och självisolering? : En kritisk diskursanalys av myndighetsuttalanden under covid-19

Kowalska, Aleksandra, Svarva Helenius, Matilda January 2022 (has links)
Folkhälsomyndigheten är en viktig aktör i det nationella smittskyddsarbetet mot covid-19. Sedan pandemins start har myndigheten haft det primära uppdraget att förse befolkningen med viktig information om det aktuella läget kring covid-19. I ett försök att kontrollera smittspridningen av viruset har riktlinjer och rekommendationer formulerats till befolkningen. Individer som är 70 år och äldre identifierades tidigt som en huvudsaklig riskgrupp att skydda från den allvarliga sjukdom eller död som covid-19 kan orsaka.  Med avsikt att medvetengöra ålderistiska inslag i officiella myndighetsuttalanden, syftar denna uppsats att undersöka hur språket som förmedlas i presskonferenserna kan tänkas konstruera och reproducera föreställningar av ålder. I denna studie kommer de förändringar i levnadsvanor som riktlinjerna medförde att problematiseras utifrån ett sociologiskt perspektiv. Frågeställningen fokuserar på hur myndigheter mobiliserar åldersrelaterade diskurser i sitt pandemisvar. Det material som avser att granskas utgår från transkript av myndighetsgemensamma presskonferenser. Med hjälp av en kritisk diskursanalys kan språket undersökas närmare. I analysen av datamaterialet fungerar Norman Faircloughs tredimensionella modell som ett vägledande redskap tillsammans med teorierna om ålderism, stigma och diskurs.  Resultaten visar att presskonferenser gällande covid-19 tenderar att kategorisera  åldersrika som en homogen och sårbar grupp i behov av skydd. Vidare bygger presskonferenserna på kronologiska ålderskategorier som kan försätta åldersgrupper i motsättning till varandra och därmed orsaka ett ”vi” och ”dem”-tänk. Studien kan bidra till att medvetengöra problematiska diskursiva uttryck om ålder som riskerar att skapa diskriminerande strukturer på såväl mikro- som makronivå.
306

Satellite derived data to support flood modelling : An application to the Po River

Ortiz Peña, Victor Alejandro, Dinic, Milos January 2018 (has links)
Satellite derived data has become an essential input in hydraulic modelling. Digital ElevationModels (DEMs) derived from different sources through remote sensing techniques have become a powerful tool for poorly gauged regions. This paper analyses the capabilities of DEMS derived from Shuttle Radar Topography Mission (SRTM) and a Light Detection and Ranging (LiDAR) and compares their accuracy against each other in a 1D hydraulic model. The study tests two different methods for inferring the river bathymetry under the water surface level for the SRTM derived DEM in order to enhance its performance, the study further analyze the reliability of remotely sensed altimetry data derived from different satellite missions (TOPEX and ENVISAT) and its suitability to complement spaceborne topographic data in hydraulic modelling.
307

Geospatial Variation of an Invasive Forest Disease and the Effects on Treeline Dynamics in the Rocky Mountains

Smith-McKenna, Emily Katherine 22 November 2013 (has links)
Whitebark pine is an important keystone and foundation species in western North American mountain ranges, and facilitates tree island development in Rocky Mountain treelines. The manifestation of white pine blister rust in the cold and dry treelines of the Rockies, and the subsequent infection and mortality of whitebark pines raises questions as to how these extreme environments harbor the invasive disease, and what the consequences may be for treeline dynamics. This dissertation research comprises three studies that investigate abiotic factors influential for blister rust infection in treeline whitebark pines, how disease coupled with changing climate may affect whitebark pine treeline dynamics, and the connection between treeline spatial patterns and disease. The first study examined the spatial variation of blister rust infection in two whitebark pine treeline communities, and potential topographic correlates. Using geospatial and field approaches to generate high resolution terrain models of treeline landscapes, microtopography associated with solar radiation and moisture were found most influential to blister rust infection in treeline whitebark pines. Using field-based observations from sampled treeline communities, the second study developed an agent-based model to examine the effects of disease and climate on treeline pattern and process. Treeline dynamics were simulated under five hypothetical scenarios to assess changes in tree spatial patterns and populations. Blister rust-induced loss of whitebark pines resulted in a decline of facilitative processes, and an overall negative treeline response to disease—despite the beneficial effects of climate amelioration. The objective of the third study was to explore whether spatial patterns of tree proximity, size, and growth infer disease patterns. Comparing spatial patterns of tree characteristics between diseased and undiseased treeline communities, I found that trees growing near trees with larger stem diameters, and larger tree islands, tended to have more blister rust cankers, and displayed clustered spatial patterns. Undiseased treeline patterns revealed near neighbors smaller in stem diameter and tree island size, and were randomly dispersed. Blister rust diseased whitebark pines reveal spatial autocorrelation, despite the complex blister rust disease life cycle. Overall, findings from this dissertation reveal the implications of invasive disease on sensitive treeline ecotones dependent on a keystone species. / Ph. D.
308

Quantification of Numerical and Modeling Errors in Simulation of Fluid Flow through a Fixed Particle Bed

Volk, Annette January 2015 (has links)
No description available.
309

Envisioning an ideal state: the literary politics of Bettina von Arnim from 1830 to 1852

Hallihan, Kathleen M. 14 July 2005 (has links)
No description available.
310

Multi-scale Modeling of Droplet’s Drying and Transport of Insoluble Solids, with Spray-drying Applications

Siavash Zamani (13140789) 22 July 2022 (has links)
<p>Understanding the drying of droplets is of interest for processes such as spray drying, where particulate materials are produced by evaporating moisture. Even though spray-drying is a widely used method, there are still challenges, such as undesired agglomeration or controlling the morphology and size of the final dried product. This dissertation develops a physics based model that is used to examine the droplet dynamics and drying kinetics at large and small scales.  In addition, the model simulates the internal motion of insoluble particles and  is used to better understand particle formation during spray drying type processes.</p> <p><br></p> <p>The first part of this work examines the effect of droplet-droplet collisions on evaporation and the size distribution at a large scale. Droplet collision dynamics are implemented into an Eulerian-Lagrangian framework, where droplets are tracked in the Lagrangian frame, and the background gas is modeled as a continuum. The modeling framework includes fully coupled interphase heat and momentum transfer between the droplet and gas phases. Binary collision of droplets could result in coalescence, reduction in surface area, or separation of droplets, resulting in the generation of satellite droplets and an increase in total surface area. By capturing the change in size distribution due to the collision of particles, our results show a linear relationship between the Weber number and the evaporation rate at low droplet number densities. Further, it is shown that droplet number density is a critical factor influencing the evaporation rate. At high droplet number densities, the relationship between the evaporation rate and the Weber number becomes non-linear, and at extremely high droplet number densities, the evaporation rate decreases even at high Weber numbers.</p> <p><br></p> <p>In the next part of this dissertation, the drying of a single droplet containing insoluble solid particles is investigated. Using a volume-of-fluid framework coupled with the Lagrangian phase, we study the particle transport within a droplet, and how it is affected by airflow, phase properties (e.g., viscosity and density of each phase), surface tension, and evaporation. Unlike the traditional one-dimensional modeling approach, our multi-dimensional model can capture the generation of internal flow patterns due to shear flow and the accumulation of solid particles on the surface of the drying droplet. Our results show that the surface tension effect is more pronounced at larger droplet diameters and low airflow velocities. Our approach also provides a quantitative method for modeling crust growth and formation. </p> <p>Our results show that increasing solids mass fraction, and decreasing particle diameter, slow down the internal transport of solid particles, leading to a more quick accumulation near the surface of the droplet. Further, despite the droplet undergoing a constant-rate drying stage, the accumulation of solids near the surface is non-linear. In addition, the inclusion of solids within the droplet drastically reshapes the formation of internal vortices compared to the uncoupled case, which determines solids distribution.</p>

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