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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.

<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>

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.

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.

Yes / Numerical simulation of wet granulation in a continuous granulator is carried out using Discrete Element Method (DEM) to discover the possibility of formation of seeded granules in a continuous process with the aim of reducing number of experimental trials and means of process control. Simple and scooped drum granulators are utilized to attain homogenous seeded granules in which the effects of drum rotational speed, particles surface energy, and particles size ratio are investigated. To reduce the simulation time a scale-up scheme is designed in which a dimensionless number (Cohesion number) is defined based on the work of cohesion and gravitational potential energy of the particles. Also a mathematical/numerical method along with a MATLAB code is developed by which the percentage of surface coverage of each granule is predicted precisely. The results show that use of continuous granulator is promising provided that a high level of shear is considered in the granulator design, e.g. it is observed that using baffles inside the drum granulators is essential for producing seeded granules. It is observed, moreover, that the optimum surface energy for scooped granulator with rotational speed of 50 rpm is 3 J/m2 which is close to the number predicted by Cohesion number. It is also shown that increasing the seed/fine size ratio enhances the seeded granulation both quantitatively (60% increase in seeds surface coverage) and qualitatively (more homogeneous granules).

Environmental concerns are becoming increasingly relevant during a period of hemorrhaging ecosystem goods and services. Restoring these would result in positive outcomes for public health and economic benefit. This thesis seeks to address two environmental concerns: (1) accurate soil mapping and (2) treatment of nitrogen to affect water quality change.The current method of soil mapping, SSURGO (USDA‐NRCS Soil survey), is often erroneous and misleading. Two studies in this dissertation are conducted to evaluate the potential that different resolution digital elevation models (DEMs) have to distribute soil characteristics successfully. These studies are conducted in southwest Virginia and western Vermont. The aforementioned studies evaluated 36 and 59 soil samples, respectively. Spatial characteristics, including slope, catchment area, and topographic wetness, are derived from several DEMs. In chapter 2, these characteristics are spatially compared, and we found that small resolution rasters result in narrow flow paths relative to coarser rasters. In chapter 3, we isolate the analysis to focus on resolution size, instead of a mix of both resolution size and generation method. This is done by recursively coarsening small rasters, deriving spatial attributes from said rasters and evaluating their potential to fit the soil characteristics of interest. Here we found that slopes generated from resolutions smaller than 11m were poor predictors of soil characteristics. Both chapters are finished by proposing and evaluating a soil map. Proposed regressions beat SSURGO in all investigated properties. Furthermore, proposed maps consistently beat out uninformed smallest resolution derived maps.Chesapeake bay water quality managers are struggling to achieve targets for nitrogen loading. This is in part due to the widespread presence of legacy nitrogen. Legacy nitrogen is an emerging issue, and springs exporting high levels of nitrogen are not uncommon in northern Virginia. This thesis explores, in part, a novel concept of treating large loads of nitrogen exported from a spring with a bioreactor. Bioreactors are a young science that most typically pair carbon heavy subterranean receptacles to agricultural drainage. This provides a location for nitrogen fixing bacteria to consume nitrate/nitrite, turning these into inert nitrogen gas. A spring fed bioreactor is studied for 10 months, and bioreactor conditions including influent and effluent nitrogen concentrations, bioreactor flow, and temperature are collected. A model driven by first order reaction equations is found to be most accurate with inputs of temperature and bioreactor age. The resulting marginal effects of these inputs were consistent with previously reported studies. / Doctor of Philosophy / Centuries of industrialization have resulted in widespread human progress but have, at times, adversely impacted the environment. Constituents rely heavily on environmental services, such as clean air and water, to subsist. Environmental degradation has resulted in detrimental effects to public health, and remediation is currently economically viable. As such, there are strong incentives for researchers to understand environmental processes at a fundamental level. One such process is soil characteristic distribution. The distribution of soil characteristics, such as soil texture or organic matter, is especially important for agriculturalists, hydrologists and geotechnicians. Soil texture and organic matter distribution can affect crop yield, nitrogen export to surface waters, and structural stability of soils. Thus, accurate characterization of measured soil properties is paramount to multiple fields. The most typically used soil map is USDA‐NRCS Soil survey (commonly referred to as SSURGO). Currently, the SSURGO database is a poor predictor of soil characteristics. There is an opportunity to improve soil characteristic distribution using digital elevation models (DEMs). As DEMs become cheaper to develop, they are typically available in multiple resolutions and generation methods. In this research, several DEMs are used to better soil maps for watersheds in Southwest Virginia and Western Vermont. Both studies showed that DEMs can better distribute soils when compared to the current SSURGO maps. Additionally, we showed that the finest resolution dataset was not always best, and mixed resolution topographic wetness indices to be most advantageous for distributing soils.Another such process is remediation of surface waters from high loads of nitrogen and phosphorus. The Haber-Bosch method of producing nitrogen fertilizer is one of the most important human innovations in recent history. This method is likely responsible for the aversion of widespread famine in the early 1900s. However, residents of multiple river systems, including the Chesapeake Bay and the Mississippi River, are suffering from the adverse effects of widespread hypoxic/anoxic (with little/no oxygen, respectively) zones within water. These have partially been responsible for the decline of commercial ventures such as fisheries and tourism. These zones are caused by eutrophication, a process of unsustainable plant growth in the presence of nitrogen and phosphorus. Water quality managers typically target agricultural runoff and point source polluters when trying to eliminate anthropogenic nitrogen. However, legacy nitrogen (nitrogen stored in groundwater in excess of a year) has become an emerging concern for water quality. It is not uncommon for springs in karst areas to be contaminated with high concentrations of nitrogen. These springs present a point source that can be treated by an emerging technology: bioreactors. Bioreactors are subterranean, woodchip filled basins that provide a location for microbes to exchange water soluble nitrogen for inert nitrogen gas. The consistency in nitrogen loading and constant flow provide stability relative to more traditional bioreactor installations. Most typically, bioreactors are installed downstream of agricultural drainage systems, and influent flow and nitrogen load depend wholly on precipitation/irrigation and nitrogen application. In this thesis, a novel spring fed bioreactor is studied. Removal rates of nitrogen are quantified using a regression driven by reaction kinetics. The analysis showed bioreactor efficiency was intimately related to hydraulic residence time, nitrogen loading, bioreactor bed temperature, and bioreactor age. The spring fed bioreactor is found to be advantageous because of its consistency, and disadvantages because springs are colder and thus less efficient than typical irrigated runoff.

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.

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