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1238 Uppsatser om Kinetic models - Sida 1 av 83

Torrefaction of biomass : a comparative and kinetic study of thermal decomposition for Norway spruce stump, poplar and fuel tree chips

Stump biomass is energy rich and stump harvesting for use as fuel become more and more interesting in Sweden. Swedish Forest Agency (2009) has estimated that stump harvesting in Sweden would respond to an annual energy supply of 57 TWh/year. However, stump has not been recognized as a bioenergy resource in Sweden. Suitable methods for pre-treatment of stump are probably of great importance to make it accepted as fuel. It is therefore rewarding to carry out an investigation in this area for stump. This report represents results from a diploma project, which was aimed to develop a fixed bed reactor for experimental study of biomass torrefaction, followed by TG analysis and kinetic modelling employing Ozawa method and different Kinetic models including one-step and three-pseudo-component models.

Kinetisk Keramik

Do ceramics have to be static? This was the question that spurred me into this work, and what kept me working on to achieve the possibility of motion in my ceramic objects. By combining the knowledge gained through my former education as an avionics technician with my interest in the ancient ceramic craft, I strive to create kinetic ceramic handicraft suitable for interaction with an audience.By a series of different phases I slowly go from understanding what kind of motion I want my objects to have, to actually realizing this motion in three-dimensional objects. Through the use of simple models made from corrugated fiberboard followed by more advanced plaster models, combined with different complementary materials such as bicycle inner-tubing and recycled aluminium cans among many others, I, through a vast series of testing, slowly build up a knowledge base later applied to the ceramic objects.The result is for me a success; I have found a way for me to combine ceramics with mechanics. Through this I have created kinetic ceramic handicraft intended for interaction with an audience..

Kinetisk Keramik

Do ceramics have to be static? This was the question that spurred me into this work, and what kept me working on to achieve the possibility of motion in my ceramic objects. By combining the knowledge gained through my former education as an avionics technician with my interest in the ancient ceramic craft, I strive to create kinetic ceramic handicraft suitable for interaction with an audience.By a series of different phases I slowly go from understanding what kind of motion I want my objects to have, to actually realizing this motion in three-dimensional objects. Through the use of simple models made from corrugated fiberboard followed by more advanced plaster models, combined with different complementary materials such as bicycle inner-tubing and recycled aluminium cans among many others, I, through a vast series of testing, slowly build up a knowledge base later applied to the ceramic objects.The result is for me a success; I have found a way for me to combine ceramics with mechanics. Through this I have created kinetic ceramic handicraft intended for interaction with an audience..

Analys av turbulensmodeller för CFD

This thesis has been a part of Forsmarks Kraftgrupp AB's evaluation of a turbulencemodel used in simulation of turbulent flow called PRNS (Partially Resolved NumericalSimulation). This model has promising properties and may be of use in savingcomputational resources. The purpose of this thesis was to analyze this model andcompare it with industrially applied models such as k-omega SST and LES (Large EddySimulations).PRNS works as a hybrid of the k-omega SST and DNS (Direct Numerical Simulation)where a constant, RCP (Resolution Control Parameter) with a value between 0 and 1are selected. This constant is then used in the calculations and determines thebehavior of the simulation. When RCP is set to zero the equation are the same as fora DNS simulation and when RCP is set to one the equations for k-omega SST issolved.

Dämpning av ljud i Shift-by-Wire växelväljare : Noise damping in a Shift-by-Wire gear shifter

Constantly growing demands from the costumers in the Automotive industry forces the subcontractors to seek alternative ways to compete. One parameter of quality is the components tolerance against NVH(Noise, Vibraion & Harshness) aspects. Kongsbergs Automotive has developed a new gear shifter platform (Shift-by-Wire) that is sold to Alfa Romeo and used in of their car models. However, the company is not pleased with the components sound quality, therefore the main purpose of this thesis is to develope a number of concepts that is supposed to enhance these NVH-aspects.To get an understanding of the problem an analysis of the causes of the emitted sound has been done parallell to a product decomposition, function decomposition and a Ishikawa-diagram. Together with these methods has a litterature study been performed to get familiar with the physics of an impact and especially the emittment of noise.

Förrotation till omrörare

The primary function of a mixer is to keep a fluid in constant motion. All mixing applicationsrequire varying degrees of small-scale turbulence and bulk flow. The performance of asubmersible mixer is measured by the thrust that it produces, while the strength of the bulkflow is dependent on the total amount of installed thrust.In a mixer, the fluid quickly flows past the propeller, and as a result, the current is mainlyaxial. The fluid will also obtain a rotating velocity, or a swirl, though this is significantly lessthan that of the propeller. During the process, the total amount of energy increases in the formof static pressure and kinetic energy.

Transferfunktionsmodeller modellering och prognoser av Sjötransportindex

We have by Statistics Sweden (SCB) been given the task of using different dynamic regression models in order to forecast service price index for sea transport. The aim is to see whether these models provide better forecasts than those previously used. This essay aim to identify, estimate and evaluate the selected prediction models. Through our data material we were given access to 28 sightings of sea transport index during the period of 2004 q1 to 2010 q4. We have chosen to evaluate three different transfer function models, one ARIMA model and one naive forecasting model. The input variables we decided to test in our transfer function models were the price of petroleum products, the port activity in Swedish ports and the lending rate of Swedish Central bank. The results of our study suggest that transfer function models generally provide better models than the ARIMA model and the naive forecast model.

Dose-related selection of Pradofloxacin resistant Escherichia coli

The study evaluated the Mutant Prevention Concentration (MPC) of Pradofloxacin on three Escherichia coli (E.coli) strains, 2 wildtypes and one first-step gyrA resistant mutant. We also measured the value of AUC (Under the Concentration)/MPC that prevents growth of resistant mutants. It is of importance to reach a concentration above MPC that prevent E.coli from developing resistance against the antibiotic.We used an in vitro kinetic model where we added bacteria? and antibiotic. The culture flask was attached to a pump with an adjustable pump-speed.

Va?gen till ett va?rdeskapande HR : En kvalitativ studie av personalarbete i en offentlig organisation

The field of work and employment is constantly undergoing changes. In order to help organizations to adjust to new conditions, different models for organizing have been developed. Many of these models are spread worldwide, due to the need for organizations to meet demands of flexibility and efficiency. In this study, a small number of models, which contains solutions of how to organize work in Human Resources, have been selected. The author and scientist Dave Ulrich, who has had a large influence on the development of the work in Human Resources, originally founded these models.The aim of this study was to examine how these models were functioning, in reference to the different departments of Human Resources labor within the township of Uppsala.

Dominerande affärsmodeller inom området informationssäkerhet

Computers together with Internet have been growing enormously, during the last decade and the area of information technology has been growing in the same speed. As long as the surrounding environment evolves, the business models must within the IT-area, keep the same pace. So, how do business corporations handle this change to attract customers? How do the dominant business models look like? In many cases, they are apparently much the same. But what differences can we see and what areas can be improved? We have showed that the IT area isn?t just one, it consist of several segments.

Börsvärdering av bioteknologiska forskningsbolag

Background: The valuation of Biotechnology companies is difficult in many ways. Patent and human capital are hard to value and also there is a great uncertainty about the success of the compaines research programs. Are traditional valuation models really useful when it comes to research companies or do they result in false values of the companies? Purpose: To study what values different valuation models gives biotechnology companies and how they correspond to the market value. Method:We have studied financial litterature och found the most common used models today.

Dominerande affärsmodeller inom området informationssäkerhet

Computers together with Internet have been growing enormously, during the last decade and the area of information technology has been growing in the same speed. As long as the surrounding environment evolves, the business models must within the IT-area, keep the same pace. So, how do business corporations handle this change to attract customers? How do the dominant business models look like? In many cases, they are apparently much the same. But what differences can we see and what areas can be improved? We have showed that the IT area isn?t just one, it consist of several segments.

Finansiella värderingsmodeller : En empirisk studie

This study tests two financial valuation models empirically by valuing three stocks from three industries, with the purpose of studying how well valuation models work empirically and to make a forecast. The models which will be tested are residual income valuation and discounted cash flow. Nine stocks will be picked strategically from the Swedish stock market and additional analysis will follow in the analysis chapter.Based on analysis and valuation, the commodities industry has decent valuation as the healthcare industry is undervalued thanks to the high valuation of AZN. The energy industry has low value due to the capital intensive nature of the industry. When it comes to the models and their practical implementation, DCF has been the most problematic to apply empirically whereas RIV was better but it still shows extreme values, which teaches the student the clear difference between theory and empiri..

Validering av vattenkraftmodeller i ARISTO

This master thesis was made to validate hydropower models of a turbine governor,Kaplan turbine and a Francis turbine in the power system simulator ARISTO atSvenska Kraftnät. The validation was made in three steps. The first step was to makesure the models was implement correctly in the simulator. The second was tocompare the simulation results from the Kaplan turbine model to data from a realhydropower plant. The comparison was made to see how the models could generatesimulation result that was similar to the reference power station.

Kvarnkretssimulering för test av styrsystem

This thesis has been carried out in autumn 2009 at Uppsala University for Boliden Mineral AB. Physical modelling has been used to model a comminution circuit. The model has then been linked to a PLC.When a concentrator is about to become operational Boliden Mineral AB have been looking for a way to test the PLC. The purpose of this report has therefore been to develop models for the subprocess in a concentrator and link these models to the PLC. The subprocess was a comminution circuit in Aitik36.

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