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400 Uppsatser om Computational Fluid Dynamics - Sida 24 av 27
Energianalys av rörledning med överhettad vattenånga
Värmetransport är ett viktigt fysikaliskt fenomen med många olika industriella tillämpningar, till exempel värmning eller kylning av en fluid som strömmar i en rörledning. Den viktigaste mekanismen för värmetransport i strömmande eller stillastående fluider är konvektion. En bättre kunskap och förståelse för den bakomliggande fysiken skulle innebära att designen av systemen skulle kunna optimeras för att erhålla en ekonomisk process genom att minimera energiförluster och kostnader för material.En ångturbin i ett kraftvärmeverk producerar elektricitet genom att vattenånga strömmar igenom turbinen. Den överhettade vattenångan transporteras sedan från turbinen i en rörledning för att användas till uppvärmning av processer i ett närliggande massabruk. I detta arbete har en energianalys genomförts på rörledningen med överhettad vattenånga efter turbinen för att bestämma temperaturfördelningen. Valet av material i rörledningen är beroende på tryck och temperatur och med för dålig kunskap om temperaturfördelningen längs röret riskerar konstruktionen att bli onödigt kostsam.En matematisk modell ställdes upp med de energibalanser som verkar på rörledningen.
Emerging infectious diseases : using PCV2 as a model of disease transmission dynamics at the livestock-wildlife interface in Uganda
Uganda anses vara ett högriskland för utveckling av nya plötsligt uppdykande sjukdomar (emerging infectious diseases, EID). Grisproduktionen i Uganda har ökat drastiskt de senaste åren och en stor del av Ugandas grisar är frigående. De kan därför lätt komma i kontakt med vilda djur i deras närområde. Porcint circovirus 2 (PCV2) är ett ubikvitärt virus och etiologiskt agens för bland annat porcine multisystemic wasting syndrome (PMWS). Förutom att infektera tamgrisar över hela världen så har PCV2 också visats kunna infektera vildsvin.
Industriella avloppsvatten i Chile : Identifiering av problem samt förslag på åtgärder
Chile and Santiago are struggling with heavy environmental problems as a consequence of urbanisation and industrialisation. In the Santiago region the air is seriously contaminated and most of the rivers are classified as heavily polluted.The aim of this thesis is to survey the industrial fluid waste situation in the Santiago region and to make suggestions on technological improvements or process changes. The purpose is also to study five different enterprises more closely and to give more detailed suggestions for improvement. Another purpose is to summarize relevant Chilean legislation.Information, provided by the supervisory authority, about the release of industrial wastewater to rivers has been analysed. Deep interviews have been made with authorities and consultants.
Konceptstudie av drivmodul till bandskotare med hybriddrift
BAE Systems Hägglunds has a long history of producing high performance terrain tracked vehicles (mostly for military applications), and they are now aiming at developing a tracked forwarder with similar techniques.The forwarder will be of series hybrid type where a diesel engine via a generator will power the motors (one for each drive wheel). Thanks to individually controlled motors and the gentle rubber tracks, this forwarder is calculated to have a considerably higher average speed in the terrain and to be more gentle to the soil. The forwarder with a weight of 11 metric tons and a load capacity of 15 metric tons is specified to have an average working speed of 7-10 km/h, a top speed in terrain of 15 km/h and a top speed on roads of 40 km/h.This master?s thesis aims at developing a conceptual design of the forwarder?s drive module which includes electric motor, gear unit, brake and drive wheel.To investigate if the requirements can be fulfilled a study of the dimensioning loading scenarios has been carried out. The resulting needs regarding the torque has been considered in order to determine the required gear ratios for different motor options.
Askans inverkan på beläggningstendensen i ett biobränsleeldat kraftvärmeverk och växtplatsens påverkan på askegenskaperna :
This report was written by Sofia Ericson and describes the degree thesis with the title: ?Connections between the growing site of bio fuel, the chemical composition of bio fuel ash and the deposit growth in a bio fuel fired boiler.? The purpose of this degree thesis was to avoid melted deposit growth in the bio fuel fired boiler at ENA Kraft in Enköping.
Potassium and sodium are known to lower the melting point of bio fuel ashes and are therefore not wanted in the trees in higher amounts than necessary for the growth. Silicon is also known to be important for the deposit growth but it is not possible to say in general if higher or lower contents of silicon is better. The relation between silicon and other chemical substances is more important than the total amount of silicon.
Att motverka dehydrering hos äldre i teori och praktik
Syfte: Att kartla?gga likheter och skillnader i a?tga?rder och hja?lpmedel mot dehydrering hos a?ldre i teori och praktik.Metod: Initialt utfo?rdes litteraturstudier via universitetsbibliotekets so?ktja?nst OneSearch. Tre intervjuer utfo?rdes pa? undersko?terskor pa? gruppboende, demensboende och hemtja?nst. Dessa erbjuder en inblick i den praktiska verksamheten.Resultat: Fo?ljande faktorer av betydelse fo?r att fo?rebygga eller motverka dehydrering identifierades samsta?mmigt i litteratur och vid intervjuer: (1) kunskap om den a?ldre via dokumentation, (2) anpassning av tillva?gaga?ngssa?tt vid servering av dryck efter den a?ldres preferenser och tillsta?nd, (3) hemtrevlig miljo? med sociala interaktioner, (4) bedo?mning av va?tskeintag, va?skebalans och riskfaktorer via uppma?rksamhet, va?tskeregistrering och med hja?lp av flera andra yrkesgrupper samt med ha?nsyn till den a?ldres historik, (5) pa?minnelser (sa?rskilt vid demens) och en stor ma?ngd la?ttabsorberade drycker som intas succesivt vid diarre? och kra?kningar, (6) la?ttanva?nda och specialutformade hja?lpmedel.
Komfortsanalys med hänsyn till vibrationer orsakade av människoaktiviteter. : Ett modernt dimensioneringsproblem för huskonstruktörer
Comfort analyses regarding human induced vibrationsIt is not too common among civil engineers in Sweden to perform comfort analyses considering the vibrations caused by human activities. In addition, the Swedish standards lack requirements to be used for comfort analyses in design of floor-systems. The demand for large spans in combination with slender slabs, is today a reason to investigate the floor-system constructions, in order to prevent disturbing vibrations and oscillations.The purpose of this thesis is to create a guide for how a comfort analysis, considering vibrations, should be implemented. Göran Svedenbjörk who is an expert in structural dynamics has been interviewed where he presents his latest project Värtaterminalen and answers some questions about vibrations due to human activities.Floor-systems, consisting of concrete slabs supported by steel or concrete beams, have been investigated with simulations in the finite element program Abaqus. In the simulations, the influence of various factors on the natural frequency of floor-systems and the acceleration level caused by dynamic loads, is studied.
Lövängen i nordöstra Skåne :
The purpose of this paper is to study how the wooded hay meadow of the forest district of northeastern Scania is preserved today, and what local history it has, to thereby achieve a better understanding of the dynamics of the landscape and the complex of problems involved in keeping a historical element of the cultural landscape alive. To accomplish this, literature concerning the subject has been studied, experts have been consulted and an example, the old farm Sporrakulla in Östra Göinge municipality, has been studied. The paper states that the wooded hay meadow constitutes an important part of the history of northeastern Scania, where it provided leaf fodder and hay for the farmers keeping cattle. Today, however, only a few wooded hay meadows remain. One of these is the studied example at Sporrakulla, where juridical protection like Natura 2000 and financial support of maintenance like miljöersättningar make sure that the wooded hay meadow will remain.
Utvärdering av C6-peptid-baserad serologi på cerebrospinalvätska som komplement vid diagnostik av neuroborrelios
Borrelios är den vanligaste fästingburna infektionen på norra halvklotet, och orsakas av spiroketer tillhörande Borrelia burgdorferi sensu lato-komplexet. Dessa bakterier kan spridas till flera organ och ge upphov till olika symptom i bland annat hud, nervsystem, leder och hjärta. Omkring 15 % utvecklar neurologiska symptom, så kallad neuroborrelios. Den bästa indikatorn på aktiv neuroborrelios är framförallt karakteristiska neurologiska symptom samt tecken på en inflammatorisk förändring i cerebrospinalvätskan (CSV) i kombination med lokalt producerade antikroppar mot Borrelia burgdorferi s.l. i CSV.
Mikrosensorer i nätverk
The purpose of this thesis is to investigate the possibility to make small, cheap and ultra low power sensor platforms, connected in wireless networks for monitoring of home and industrial environments. The concept is based on ideas from our supervisor, Jerry Lindblom. The developed system consists of a generic platform for different sensors, a receiver and software. A GPRS module from RO Rollytech AB and a database from Gema Industri AB have been modified and used to demonstrate an example of a complete system. To the platform, it is possible to connect any resistive sensor and any sensor that can act as a switch.
Unga Bestånd - en tillgång i park- och landskap : woodlandkvarter från Alnarp till Jönköping
This is a thesis about design of young stands of trees. A big source of inspiration has been Västerskog and Tor Nitzelius Park in Alnarp which both consists of a structure of squares. I wanted to examine if this type of planting could be valuable from an aesthetic and recreational point of view. One problem today is that many people believe that we have to wait for decades for a planting to grow up so that we can enjoy the ?ready result?.
Årstidsdynamik för kvicksilver i ett sövattensediment :
The limit for mercury in fish, set by health authorities, is exceeded in about half of the lakes in Sweden. Methyl mercury (MeHg) is the most toxic form of mercury and accumulates in fish. Therefore transformation of inorganic mercury (Hg) to methylmercury (MeHg) is an important process that we need to understand in order to possibly counteract the negative effects of mercury in the environment.
The seasonal dynamics of mercury biogeochemistry is likely of great importance for the accumulation of MeHg in the aquatic food web. In thesis the chemical speciation and transformations of Hg and MeHg in bottom waters and sediments is followed in Ängessjön, a small lake located on the east coast in the middle of Sweden. The lake is not directly affected by any industrial pollution and concentrations of Hg in the sediment reflect the atmospheric deposition in this area, as well as processes taking place along the hydrological pathways from soil to lake.
Samples from sediment, bottom- and streamwater were collected in average every second month during the period Feb.
Kylning och torkning av ett högtryckskompressorinlopp
Examensarbetet utfördes på University of Florida vid Department of Mechanical and AerospaceEngineering i deras Energy and Gas Dynamics Systems Laboratory. Laboratoriet forskar på enny gasturbincykel som producerar kraft, värme, kyla och vatten. Cykeln är kallad High PressureRegenerative Turbine Engine (HPRTE) och kombinerat med gasturbincykeln är ettabsorptionskylsystem (VARS). Kylsystemet drivs av spillvärme från avgaser som cirkuleras igasturbinen, den producerade kylan används för att kyla ned högtryckskompressorinloppet.Syftet med det här examensarbetet är att undersöka möjligheten till att kyla ned inloppet tillkompressorn till temperaturer långt under fryspunkten för vattnet i den fuktiga gasen. Om gasenskall kylas till nivåer under fryspunkten måste vattnet föras bort från gasen.
Musik som socialt redskap - Musikens betydelse i arbetet med socialt utsatta barn, en studie ur ett rytmikmetodiskt perspektiv
The main purpose of this study is to inquire whether music can function as a supportive and compensating tool for children from various kinds of social exposure. Eurhythmics is the musical method focused on, since it consciously works out of a socializing perspective. The study involves a scheme with poor children in Argentin (autumn 2005) and is based upon two interviews with women working professionally with both the social and the musical aspect of the current question. Notes from the above mentioned project are added to the interviews. The possible conclusion from the end results is that the individual as well as the dynamics of the group (as a whole) draw positive benefits from not only the music itself but also the structure and the elements of it.
The Psychology Driving&Barriers to Skunk Work Project
The Psychology Driving and Barriers to Skunk Work Projects (referred to throughout this thesis as the paper) represents a study predominantly on Tetra Pak from a selective perspective, the innovators. Innovators both past&present whose initiatives contribute to the well being of Tetra Pak as well as one from Ericsson were consulted. As with individuals, organizations possess definable characters that are influenced by the various stages of their life cycle. Theories of corporate life cycle phases and organizational character analysis were therefore employed to identify and explain organizational barriers to skunk work leaders&managers. Predicated on the Organizational Character Index survey developed by William Bridges PhD (himself a recognized leader in the field of transition management) and administered to sixty-one managers within a Tetra Pak business unit established the benchmark.