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499 Uppsatser om Fluid simulation - Sida 23 av 34
Förstudie till flödesackumulering på Astra Tech
Syftet med arbetet var att undersöka möjligheten för optimering av produktflödet. Företagets produkter transporteras på ett transportband till en gemensam process. Det nuvarande flödet till processen är inte optimerat vilket resulterar i att processen körs ineffektivt. Ackumulering av produkter innan processen ska därför undersökas som en lösning till problemet.Fyra olika ackumuleringsförslag har analyserats och jämförts: hängande bansystem, palleteringssystem, depalleteringssystem och kombination av bansystem och palleteringssystem.Förslagen har blivit bedömda och jämförda utifrån följande parametrar: yta, investeringskostnad, flexibilitet, arbetsbelastning, arbetsmiljö och tid. Hängande bansystem fick det högsta snittvärdet och valdes därför för fortsatt analys med stöd av simulering.
Simulation of rattan harvests in Indonesia : different harvesting pressures and the resulting patterns
The objectives of this research were to determine whether the natural rattan resources in Sulawesi, Indonesia can cope with the strongly increased harvesting pressure that has occurred over the last centuries. I was furthermore looking for patterns in the rattan population dynamics that might give a hint on how the harvesting system could be improved to ensure a maximum sustainable yield. To
answer these questions, I developed an individual-based model to analyse the dynamics of rattan growth in connection with rattan harvests by locals to identify sustainable levels of rattan harvests around villages in Sulawesi, Indonesia. Scenarios with different harvesting intensities were run to compare the change in harvest amount. For a given harvesting pressure, scenarios with a high number of harvesters and a low harvesting frequency had the same effect as scenarios with high harvesting frequencies and a low number of harvesters.
Ett första steg mot högre matematik : om gymnasieelevers upplevelse av en kurs i högskolematematik vid Kungliga Tekniska Högskolan i Stockholm
Forskning med hjälp av mikroskopi har med tiden ställt merspecialicerade krav på utrustning som används. Utrustningenhar blivit mer bättre men samtidigt också dyrare. Enhög kostnad innebär att avancerad mikroskopi inte kan användassom ett utbildningsverktyg inom grundutbildning.Dagens studenter tvingas på så sätt förberedas för framtidensforskning genom att använda gårdagens utrustning.I detta arbete visar vi hur virtuell mikroskopi kan användasför utbildning och forskning. Virtuell mikroskopi kananvändas som komplement, eller möjligtvis ersättning, förbefintlig undervisning. Vi har demonstrerat detta genomatt utveckla en pilotapplikation som simulerar de två metodernaFLIP och FRAP.
Partikelformulering av fluider. Flödessimulering utifrån en partikelbaserad beräkningsalgoritm.
I fo?ljande arbete underso?ks en partikelbaserad simuleringsmetod som kallas Fluid-partikelmetoden, FPM. FPM a?r designad fo?r att simulera komplexa fluiders beteenden pa? mesoskalan, vilken sammanla?nkar kontinuumskalan med den molekyla?ra skalan. Metoden utvecklades av Pep Espan?ol i slutet av 1990-talet och a?r en vidareutveckling och generallisering av Dissipative Particle Dynamics som togs fram av Hoogerbrugge och Koelman under tidigt 1990-tal.
Vad kostar deltid? Kvinnors deltidsarbete ur ett pensionsperspektiv
Mothers of small children often work part-time in Sweden. Since old age pensions are based on lifetime income, part-time work leads to lower pensions, as long as there is no compensation from non-actuarial benefits such as minimum pensions. In this paper, I investigate whether different components of the Swedish pension system provide incentives for part-time work among women. The analysis is performed through a simulation of future pensions for 9 typical women in a certain cohort. For three levels of education, I compare pensions of women with different labor market participation rates in different growth scenarios.
Klassningssällskapens regelverk, ett möjligt verktyg för att skapa stryktålighet på örlogsfartyg?
I denna uppsats behandlas hur klassningssällskapens regelverk kan bidra till ett örlogsfartygs överlevnad vid vapenverkan. Syftet är att undersöka om regelverken kan användas för att implementera stryktålighet genom sina notationer och krav på redundans, separation och skydd mot splitter.Arbetet inleds genom kunskapsuppbyggnad av teorier som behandlar örlogsfartygs överlevnad, vilka sedermera bildar arbetets teoriram. Sedan sker en analys av regelverken samt en fiktiv operativ miljö skapas för att ta fram taktiska uppgifter samt hot, vilka sedan omvandlas till verkansdelar och kritiska system. Därefter skapas modellerna som tillsammans med verkansdelarna används i simuleringen som genomförs i simuleringsverktyget Semiautomatsikt fartygs verktyg för AVAL. Simuleringarna mäter utslagssannolikheter av olika funktioner ombord vid påverkan från de framtagna verkansdelarna.
Passivhus, detaljutformning och dess köldbryggor
Along with rising energy prices and increasing awareness of environmental issues, the criteria for buildings energy performance have been sharpened through the years. Today, ?passive house? and ?low energy house? are commonly used phrases in the construction industry and is expected to become increasingly common in the future.For houses with well-insulated building envelope the importance of well constructed details increases when minimizing the heat losses. Examples of these details are floor-wall junction and window openings in the wall. In such connections thermal bridges occur, which means that heat more easily is transported out of the building, compared to the rest of the building envelope.This report deals with detail solutions around windows and a comparison between a traditional slab and a foundation from Koljern consisting of foam glass.
Modellbaserad temperaturregleringav partikelfiltrets regenereringsprocess
Due to increasing regulations regarding new diesel vehicles particulate matteremissions the new Scania truck, Scania Euro 6, has been equipped with a particulatefilter. This component effectively stores the particles in the exhaust gas but must becleaned in order to prevent itself from clogging. The filter is cleaned through aprocess named regeneration which is a thermodynamic process in which thetemperature of the filter is raised through fuel supplied to the exhaust gas.The purpose of this thesis is to contribute to the development of improved controlstrategies of the temperature during the regeneration process through thedevelopment of model-based controllers. These controllers are designed in order tohave good performance in stationary as well as automatic regeneration.In order to develop these model-based controllers a model of the system isconstructed. The model is described as a linear thermodynamic grey-box model withflow varying parameters, showing good results in validation.The model provides a simulation environment during the controller design, which isfocused around the development of linear regulators with the exhaust gas mass flowas a scheduling variable whose size determines controllers? mode of operation.
Optimization of Burner Kiln 7, Cementa Slite
In this report focus is put on the combustion process at a cement plant. Combustion is the
heart of the cement making process and absolutely crucial to have under full control and well
optimized.
The fuel is put into the process through a burner pipe and this burner pipe is modified to
reach a more efficient combustion. The primary target is to enable burning of heterogeneous
alternative fuels and increase the production level. Other positive effects from this type of
optimization is lowered specific fuel consumption and lowered CO2 emissions.
A redundant burner is chosen for the project and overall the project steps are the following:
1. Installing a Jet air nozzle ring in a way so it can move both axially and radially due to
temperature changes.
2.
Klinisk gradering av hästens luftvägsstatus : en jämförande studie av kliniska graderingsprotokoll samt deras relation till luftvägshälsa och neutrofilförekomst i BAL-vätska
Respiratory disease with airway inflammation as main characteristic is common in the horse. It is a syndrome that is not yet fully understood. The etiology, pathogenesis and classification into different disease states are subjects for discussion and under continuous revision. Despite a number of modern techniques, the diagnostic procedure is challenging. There is no test considered to be gold standard when diagnosing these diseases.
Förstudie för skapandet av ett miljöövervakningsprogram : en styrkeanalys angående vattendrag i västerhavets vattendistrikt för fastställandet av provantal i tid och rum för ett effektivt omdrevsprogram
The environmental monitoring in Sweden has been developed by several different parties and is now being coordinated and made more effective in order to meet the current demands on high quality information regarding the state of the environment. Sweden has been divided into five different water districts based on watershed areas because of requirements in the Water Directive of the EU. In Sweden there are two common types of environmental monitoring programs used to gather information on changes in time and in space. Currently both these two types are used for lakes in the water district of the western sea but only one is used for watersheds.
The purpose of this report is to supply basic information regarding the possible need for a second environmental monitoring program for watersheds in order to better describe the spatial variation within the district as well as to determine the number of samples necessary in order to describe the district over time and space.
Development of Liquid Cooling for PCs
In recent years, existing solutions for cooling personal computer CPUs have been supplemented by a new product category, factory sealed water cooling loops. These systems, consisting of a water block with an integrated pump, a fan and a radiator, perform well compared to the air cooling solutions but are less effective than larger, custom-built water cooling systems.This project aims to explore the most important aspects of a factory sealed system and to identify possible cost-effective enhancements of the performance.The most significant differences between the different groups of water cooling loops are the block design and the pumping power. The performance of both categories is also largely dependent on the fan power, but increasing fan power has a large negative impact on the noise level.Both radiator size and fan model choice appear, in tests, to be relatively unimportant, presuming that the noise level is kept constant. The position and direction of the fan, however, has significant impact on both the temperature and the sound level.Water blocks can be designed in several different ways, both regarding the heatsink design and the flow direction. In simulation, flow with the inlet centered above the heatsink result in considerably lower pressure drop and slightly higher temperatures than flow through the block, for heatsinks with fin arrays.Creating a competitive product in this product segment certainly seems possible, as there are performance-increasing changes to be made that seemingly has little impact on the production cost.
Molekylärgenetisk analys av dilaterad cardiomyopati hos hund :
Canine dilated cardiomyopathy (DCM) is a disease with high morbidity and mortality and with a high prevalence in certain breeds. Predominatly large breeds are affected, such as Great danes, Newfoundlands, Deerhounds and Dobermanns. One exception is Cocker spaniels, where both American and English Cocker spaniels are affected in a quite high frequency.
Cardiomyopathy is characterised as a disease that affects the myocardium and gives an impaired heart function. To diagnose DCM following criteria have to be observed:
1. Dilation of the left ventricle.
2. Reduced systolic heart function.
3. Increased sphericity of the left ventricle.
To be certain of the diagnosis, alternative reasons for the symptoms such as lung- and heart diseases with other etiologies have to be excluded
Two different types of DCM have been found upon histological examination.
Vätskepreferenser hos unga kalvar
Den vanligast förekommande sjukdomen hos unga kalvar med infektiös orsak i Sverige är diarré. Enterit kan leda till uttorkning, acidos, rubbningar i elektrolytbalansen och i värsta fall dödsfall. Snabbt insatt behandling är avgörande. Till kalvar med fungerande digestionssystem rekommenderas i första hand behandling med oral vätsketerapi. Endast lite forskning har utförts om hur kalvar helst dricker sitt vatten.
Sommar, landsbyggd och natur : att skapa ett varumärke med grön image
Bakgrund: I och med att Basel II har instiftats i Sverige så måste finansiella institutioner beräkna sin marknadsrisk på sina portföljer. Detta kan göras genom olika VaR metoder. Dessa ger dock olika uppskattningar på marknadsrisken. De finansiella instituten får använda sig av den metod som de anser reflektera marknadsrisken bäst. Det finns dock ingen metod som utsetts till standard.Syfte: Syftet med detta arbete är att jämföra olika VaR-metoders skattning av marknadsrisken utifrån verkligt utfall, för att urskilja vilken metod som är funktionsdugligast.Avgränsningar: Denna undersökning inkluderar fyra olika VaR metoder.