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1184 Uppsatser om Plant Simulation - Sida 24 av 79
Tillämpning av en markprofilmodell för hydrologiska beräkningar i avrinningsområdesskala
There is a great need to reduce nutrient leaching from arable land into lakes and oceans. By using several different types of models it has previously been possible to describe nutrient losses in a catchment area with a minimum unit of sub-catchment level. At present, it is instead desirable to model a smaller catchment with an opportunity to re-connect the results to the corresponding fields in the catchment. Such models already exist but they are not fully able to properly describe Swedish conditions and land characteristics in our region.With the approach of creating such a model, SLU has developed a project with this work as its first stage. The model is expected to be created under the working name SWE-model which stands for Soil Water Environment and is in this first stage supposed to apply the SOIL model in catchment scale. During the procedure to describe the first step in the process of developing such a model adapted to Swedish conditions and which works in the catchment scale with an area of about 10-30 km2, focus has been set on calculating the transport of water flow from different hydrological response units. Regardless of the processes occurring in the soil after the water has been added, it is assumed that all the water which flows from each simulated unit is drained.In the first step the hydrologic response units were identified based on land use and soil type in the study area. With the help of a script with functions that retrieve and transform data, certain units were chosen for simulation. The script was also created in this project. Finally, the model results were aggregated and summarized for each unique unit, for each sub-catchment, and also for the whole catchment.From the results it is possible to see similarities in the flow dynamics between modeled and measured data. The efficiency coefficient has been calculated to correspond to the mean of the measured values for the whole simulation period. With an automated calibration process the model should be able to perform better. The volume error gives an indication of overestimation from the model..
Energieffektivisering av färskvattensystemet på Skärblacka pappersbruk
The purpose of this master thesis was to study the water system for mechanically cleaned water at Skärblacka mill, in order to find and evaluate possibilities of using energy more efficiently. The thesis also includes an evaluation of the software tool ?Pumpanalys?Skärblacka mill produces pulp and paper. The large amount of water required is cleaned mechanically through filters and called mechanically cleaned water (MR0). The MR0 water is pumped out to the factory by four crude water pumps.
Forsmark 3 ?Ett Framtida Biobränslekraftverk?
Recent turmoil surrounding nuclear power as an energy source, especially since the accidentat Fukushima, has largely contributed to the debate of whether or not nuclear power should beused as an energy source. This study has examined the economic feasibility of replacingForsmark?s 3rd nuclear reactor with a bio fueled power plant, and find out how this could bedone.The power generation that has to be replaced is equal to 1170 MWe. To replace this, 6 largescaleCFB-boilers, each providing over 200 MWe, were necessary. In addition to this, eachboiler required their respective turbine sets, comprising one high-pressure-, and one lowpressureturbine with intermediate reheating capacities.Based on this, a rankine-cycle was modeled using the software EES, to be able to calculatethe total heat required in the power plant.
Värmeöverföring i bergvärmesystem : En numerisk analys av den ringformade koaxiala borrhålsvärmeväxlaren
The borehole heat exchangers of today suffer from poor thermal and hydrodynamic performance. The purpose of this thesis is to improve the performance of ground source heat pump systems and thermal energy storages by increasing the energy efficiency of the borehole heat exchangers. For this reason, the annular coaxial borehole heat exchanger (CBHE) has been analyzed. This type of heat exchanger is interesting in terms of both thermal and hydrodynamic performance. A model has been set up in the program Comsol Multiphysics in order to investigate the heat transfer characteristics along the borehole.
Effect of plant maturity at harvest of haylage on digestibility and faecal particle size in horses fed forage-dominated diets
Time of harvest affects nutritional value and digestibility of haylage since plants are in different developmental stages. The aim of this study was to examine the effect of plant maturity of haylage cut in June, July and August on digestibility and faecal particle size in horses.Forage and faecal samples used for the analysis of apparent dry matter digestibility (DMd) and particle size distribution in faeces were from a feed-study performed in the autumn of 2009. Twelve horses were used in the study, divided into three groups in a change-over experiment. Each group was fed haylage harvested in June, July or August during three periods. Faecal grab samples were taken from each horse and pooled so that one sample represented one horse during one period.
Planteringar på Marieholm med 1800-tals växtmaterial och tillhörande skötselplan
Uppsats för avläggande av filosofie kandidatexamen iKulturvård, Trädgårdens hantverk och design, 22,5 hp, 2014.
Nyckeltal för älg och fodertillgång på tall Pinus sylvestris och rönn Sorbus aucuparia
It has been shown that moose can affect plant community composition and structure. Selective browsing with other damages of large herbivores on tree species with different tolerance to disturbance could reshape the tree layer in both managed and natural forests. Rowan Sorbus aucuparia is widely distributed throughout Sweden and Europe. Research has shown that browsing by moose may prevent rowan from reaching browsing safe heights. The goal has been formulated that, where rowan is indigenous, it should have a good competition status and be able to reach tree level.
Patotyptest av potatiscystnematoden :
There are two species of potato cyst nematode (PCN), the yellow, Globodera rostochiensis, and the white, Globodera pallida. Each of them can appear in different pathotypes. These are separated by testing the nematode ability to multiply on a number of potato cultivars with different resistance properties. The aim of this project was to examine the virulence of Swedish and foreign PCN populations and to compare two test methods. Biotests are today the only available tests used to study virulence.
Simulering av översvämningar i Byälven
Severe floods caused by heavy autumn rains in year 2000 raised the question whether measures to reduce the damage from high water levels, in the area surrounding lake Glafsfjorden and along the river Byälven down to lake Vänern, are possible. One option is to reduce flow resistance along the river and thereby lower the maximum water level a given inflow would cause. Good knowledge of hydraulic and hydrological conditions is necessary in order to estimate the effect of such flow-reducing measures. In order to quantify such effect a 1-dimensional hydraulic flow model has been set up for the river Byälven using the software package MIKE 11. The model is more detailed, especially concerning topography and bathymetry, than earlier models used for studies of the river.
Sammankoppling av fjärrvärmenäten i Nyköping och Oxelösund : miljö- och systemkonsekvenser
District heating covers most of the residential areas and industries in the twoneighbouring Swedish municipalities Nyköping and Oxelösund. In Nyköping,Vattenfall AB Värme produces heat in a bio-fuelled CHP plant. In Oxelösund,waste heat and use of waste gases from the steel production at SSABOxelösund is the basis in the district heating system.This report examines the environmental consequences of a connection betweenthe two district heating systems. A broad system approach is used and the focusis on environmental effects in the system.A system analysis has been performed on the result of simulations of differentheat and electricity production alternatives. The alternatives simulated wereone where Vattenfall Nyköping covers the base load in the joint district heatingsystem and two where the power plant at SSAB Oxelösund supplies the heatbase load.The conclusion in this report is that the consequences of connecting the twodistrict heating systems can be both positive and negative, depending onsystem boundaries and on the environmental focus.
Träd och buskar i kantzoner : en undersökning av kanteffekter i några av östersjöregionens skogar
Around the world, forests are generally being fragmented and as plant populations decline in both sizeand number of individuals, the genetic variation will also decrease whitch in the end leads to totalextinction of the plant. In this paper, I wanted to investigate what specific species of trees and shrubsyou usually find in the edge and core habitats in some of the forests in the Baltic Sea region. I alsowanted to identify the edge effects and their sources and finally compare the results between thedifferent regions.The data sources used are derived from the ongoining research project Landscape structures, patterns ofbiodiversity and conservation strategies in the Baltic Sea region by Kari Lehtilä, Patrik Dinnétz ochTiina Vinter who have made a record of all herbaceous plant species in four randomly chosen forestregions situated around the Baltic Sea: Estonia, Skåne, Södermanland and Germany. I made statisticalanalyses, using the computer program R, concerning the distribution of species in the edge habitats ofthe forests as well as in the core habitats. I performed generalized linear models and then variationanalyses with the factors light and biomass in order to investigate wether edge effects might appear dueto these factors.
Process optimization in the steel plant
Blast furnace is the heart of every steel plant. Steel production is based on the blast furnace process, as it is where the iron is extracted from the iron ore and turned into liquid iron, which will subsequently be used to make liquid steel. Therefore, without hot iron, steel can not be produced. Blast furnaces in this process are supplied among others with pulverized coal. Raw coal should be prepared for the blast furnaces in the form of fine coal powder.
Effektivisering av destruktionsprocess : En förstudie om hur Fresenius Kabi kan effektivisera befintlig destruktionsprocess
This thesis is a feasibility study into how Fresenius Kabi may rationalize their destruction process in regards to cost, recycling, and work environment. The two main objectives are to identify scrap flows and the possibility to improve or replace the equipment that is now carrying out the physical scrapping. The flow has been visualized by a flow chart of the material and communication. A chart of the problem established to visualize where improvements are necessary. Based on the problems proposals are presented on how to improve the flow thru the plant.During analyze of the physical scrapping equipment it was also necessary to take a deeper look at how they are carrying out there work today, how does the procedure look like, working environment and where are the weaknesses.
Modellstudie av föroreningsretention i Bäckaslövs våtmark : Tillämpning av modellverktygen MIKE SHE WET och MIKE 21
During the nineties, ecological handling of urban storm water became very popular in Sweden. Together with Chalmers University of Technology and two Swedish communities, DHI Water and Environment has been doing research of storm water ponds and constructed wetlands. This thesis work is a part of that research project. The work has been applied at the Bäckaslöv storm water treatment plant in Växjö, Sweden. The plant consists of one storm water pond and a downstream constructed wetland.
Beteende inför lek hos odlad respektive vild lax (Salmo salar L.) i Klarälven
In many regulated rivers, authorities have stocked hatchery salmon to compensate for loss of wild populations. However, hatchery fish have not always behaved as wild fish do, and stocking them has not always fully compensated for the loss of wild fish. The purpose of this study was to compare swimming behaviour in the river before spawning, the choice of spawning areas and body size between wild and hatchery-reared salmon in the river Klarälven. Salmon behaviour in the river before spawning was analyzed using radio telemetry. The salmon were caught at Forshaga power plant, radio-tagged and returned to Klarälven at Ekshärad, 107 km from the river?s mouth.