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499 Uppsatser om Fluid simulation - Sida 2 av 34
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.
Elektrolytlösningar som vätsketerapi hos mjölkkor med löpmagsförskjutning :
Ten cows suffering from displacement of abomasum (DA) were treated with two different electrolytesolutions. The DA cows showed symptoms typical for the disease. Four out of 10 cows had a metabolic alkalosis and two a metabolic acidosis. The cows were mildly hypocalcemic, and 9 out of 10 were mildly to moderately hypokalemic. Six out of 10 cows showed muscle fasciculations.
Vätsketerapi : experimentell studie med två infusionsaggregat
Background: In small animal healthcare fluid therapy is an important area. To get an adequate treatment there are several factors that may play important roles in this matter. One of these factors is the correct use of the administration technique.
Aim: The aim was to investigate how correct the amount of prescribed fluid was given when different people set up a fluid administration set.
Method: An experimental study was performed to compare two different infusion techniques.
Value-at-Risk : Historisk simulering som konkurrenskraftig beräkningsmodell
Value-at-Risk (VaR) is among financial institutions a commonly used tool for measuring market risk. Several methods to calculate VaR exists and different implementations often results in different VaR forecasts. An interesting implementation is historical simulation, and the purpose of this thesis is to examine whether historical simulation with dynamic volatility updating is useful as a model to calculate VaR and how this differs in regard to type of asset or instrument. To carry out the investigation six different models are implemented, which then are tested for statistical accuracy through Christoffersens test. We find that incorporation of volatility updating into the historical simulation method in many cases improves the model.
Virtuellt ledarskap i näringslivet: Hur affärssimulering kan skapa kompetens, samsyn, och ökad ekonomisk förståelse i en organisation
The purpose of this thesis has been to explore the topic of business simulation from a theoretical foundation in social constructivism and theories concerning leadership as the management of meaning. The most important findings are that business simulation can be used for strategical leadership by management to create a common vision in the organisation members, which affects their perception of the business and the decisions and actions they make, which in turn can lead to a more efficient organisation that becomes better at meeting set goals. This can be viewed in different ways from different theoretical viewpoints: as inducing targeted changes in mental models to create changes in decision making and actions; as a secondary socialization process where the vision of management is externalized as a business simulation that is in turn internalized by the organisation members that participate in the business simulation, or as a way to frame and define the reality of the organisational members which creates a shared reference point against which a feeling of organisation and direction can emerge. In the future, business simulations may become increasingly used by organizations to create a common vision or to communicate a new decision to the organization members..
Tillfällen då hemodialyspatienter anser det vara svårast att undvika vätskeintag : En empirisk studie
The aim of this study was to investigate which situations haemodialysis patients consider as the hardest for avoiding fluid intake. The data collection was performed with a questionnaire which was distributed to haemodialysis patients who fulfilled the inclusioncriteria. Of 158 haemodialysis patients 103 haemodialysis patients chose to participate in the study. The participants were chosen from different dialysis centres (n=12) in north and south of sweden, excluding the middle of Sweden. The questionnaire that was given out consisted of 32 situations, the response format included nine alternatives, that included different kind of difficultes.
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.
Framtagning av ritplattestyrd penselsimulation för GIMP
The project was intended to produce a brush simulation plugin to the image processing program GIMP which would use a 6DOF drawing tablet for user input.Too ambitious goals coupled with compability issues between the resources used resulted in that no meaningful software was produced. Experience was however obtained, and this paper is intended to give an overview of relevant concepts for- and the process ofcreating a brush simulation..
Lanczos potentialer i kosmologiska rumtider
We derive the equation linking the Weyl tensor with its Lanczos potential, called the Weyl-Lanczos equation, in 1+3 covariant formalism for perfect fluid Bianchi type I spacetime and find an explicit expression for a Lanczos potential of the Weyl tensor in these spacetimes. To achieve this, we first need to derive the covariant decomposition of the Lanczos potential in this formalism. We also study an example by Novello and Velloso and derive their Lanczos potential in shear-free, irrotational perfect fluid spacetimes from a particular ansatz in 1+3 covariant formalism. The existence of the Lanczos potential is in some ways analogous to the vector potential in electromagnetic theory. Therefore, we also derive the electromagnetic potential equation in 1+3 covariant formalism for a general spacetime.
En undersökning av VaR-modeller med Kupiecs Backtest
SAMMANDRAGHistorisk Simulation, Delta-Normal och RiskMetrics prestation utvärderas med hjälp av Kupiecs Backtest. Value at Risk (VaR) beräknas med tre olika konfidensnivåer utifrån Affärsvärldens Generalindex och HSBC kopparindex. Utifrån överträdelser från verkligt utfall undersöks vilken VaR-modell som estimerar marknadsrisken bäst. VaR-modellernas prestation jämförs, och i analysen utreds hur konfidensnivå och tillgångars egenskaper påverkar VaR-modellernas prestation. Resultaten visar att Historisk Simulation presterar bättre än Delta-Normal och RiskMetrics på den högsta konfidensnivån vilket troligtvis beror på att RiskMetrics och Delta-Normal antar normalfördelning.
Beräkningsverktyg för plattformar till seriekompenseringsanläggningar
ABB is one of the world?s leading engineering companies in power and automation technologiesand their solutions improve performance while lowering environmental impacts for energycompanies and industries. ABB FACTS designs equipment and plants for series and phasecompensation.This thesis has been performed at ABB FACTS on the Mechanical Design (DM) department inVästerås, Sweden. The purpose of the thesis was to develop and design calculations andsimulation tools for ABB FACTS?s standard series capacitor platforms.
Jämförelse av olika metoder att generera Bernoullifördelade slumptal givet deras summa
In this master?s thesis the problem of simulating conditional Bernoulli distributed stochastic variables, given the sum, is considered. Three simulation methods are considered, namely the acceptance/rejection technique, Bondesson?s method and the Markov chain Monte Carlo method.To compare the three methods the bias and the standard deviations of the simulated variables are evaluated. The results of the simulation study shows that the Markov chain Monte Carlo method is not the best method for this type of simulation.
Glycerol till mjölkkor : effekter på våmmetabolismen
Glycerol is essential for the lipid metabolism of both plants and animals. Glycerol is formed in the rumen by hydrolysis of lipids from the feed. Glycerol is also a by-product from the production of biodiesel from rapeseed oil and other fat sources. Glycerol might be used as a dietary glucose precursor for dairy cows in similar ways as propylene glycol. Due to increased production of biodiesel more glycerol has been available to a lower price.
Säkerhetsegenskaper hos en rymdreaktor
A Monte Carlo simulation of the ELECTRA reactor using (U,Zr)N fuel and a liquid lithium coolant is performed using the Serpent simulation code. The results show a reactor with a total reactivity coefficient of the coolant, fuel and material expansion that is strongly negative. These properties make the ELECTRA reactor a good candidate for a safe space reactor that could be used for propulsion of manned and unmanned space vehicles to Mars and other parts of our solar system..
Risk för dehydrering och svält preoperativt. : En kartläggning av preoperativa fasteperioden hos patienter med kroniskt subduralhematom
ABSTRACT The purpose of this medical record research was to study 30 patients with chronic subdural hematoma on a neurosurgical clinic, mapping documented nutritional status, preoperative fasting and hydration and energy supply before surgery. In addition peroperative administration of fluid and vasoactive drugs, as well as postoperative complications and length of hospital stay were studied. The mean age of the patients was 71 years. Nutritional status was evaluated in 12 patients, out of these seven were judged to be at risk for under nutrition. Fifteen patients had surgery day 1 (total fasting time on average m 11 h), eleven had surgery day 2(29 h), three had surgery day 3 (35 h).