Sökresultat:
370 Uppsatser om Numerical simulations - Sida 14 av 25
Systemidentifiering och reglering av en luftningsbassäng på ett reningsverk
A wastewater treatment plant has the task to refine the wastewater from substances that should not be released into the environment. The decomposition process can, in a simple way, be described as follows: micro-organisms breathe oxygen and eat unwanted substances. The environment in which the micro-organism lives is known as sludge and the correct amount of oxygen available in the sludge is important for the decomposition to be effective. The oxygenation of the sludge alone stands for about 30% of the plant?s energy consumption.
Numeriska simuleringar av betongkonstruktioner med minimiarmering för sprickbreddsbegränsning
Efter introduktionen av Eurokoderna har mängden minimiarmering i betongkonstruktioner ökat. Denna ökning beror på skillnader i metoderna som nu används för att beräkna mängden minimiarmering i olika typer av betongkonstruktioner och de som användes tidigare då BKR var den gällande normen. Minimiarmering används i betongkonstruktioner för att omfördela tvångsdeformationer. I detta arbete undersöks om mängden minimiarmering kan minskas utan att dess huvudsakliga funktion går förlorad. I arbetet har ett antal metoder för att beräkna minimiarmering jämförts för att se hur stora skillnaderna i armeringsmängd blir, varför dessa uppkommer och vilka för- och nackdelar som finns med metoderna.
Radioräckviddsberäkningar för flygande plattformar
There exist several known methods for calculation of radio coverage for ground-based systems. As far as we know there are no equivalent methods for the case of flying platforms when the altitudes and speeds are significantly different to those of ground-based systems. This thesis describes the theoretical concepts behind calculations of radio coverage for flying platforms. An investigation is made to sort out what is important and possible to employ in a model for simulations. A method is described and implemented in a program for evaluation of flying radio systems.
Cykeltidsoptimering av sjuaxligt robotsystem
This master thesis studies how much the cycle time, i.e. the time it takes for an industrial robot to perform a given task, can be reduced if an extra degree of freedom (DOF) is added to the robot system. The extra DOF consists of a linear track, which is supposed to be used in an optimal way. The problem has been studied using simulations in the robot simulation tool RobotStudio. To be able to run an optimization in Matlab, with the RobotStudio simulation cycle time as the object function, communication between Matlab and RobotStudio has been set up with an interface written in Visual Basic.
Computer Modelling of the Influence of Surface Topography on Water Repellency and a Study on Hydrophobic Paper Surfaces with Partly Controlled Roughness
A computer model based on minimization of the free energy, capable to predict contact angles and spreading transitions between Wenzel and Cassie mode for drops placed on surfaces with different topography were implemented in matlab. Simulations were compared with experiments documented in the literature. These showed that reported transitions between Cassie and Wenzel mode can be explained by minimization of the free energy. In this report, a study on the possibility of constructing water repellent paper surfaces with a combination of treatment with octadecyltrichlorosilane and topography changes, is included..
CFD simulering av kallras : Undersökning av temperatur- och luftbeteende intill höga glasfasader och i vistelsezon med golvvärme som en värmekälla
Glass has sophisticated front properties and are used as facades in high buildings. During cold periods, these glass facades could cause thermal discomfort, due to cold downdraught. Cold downdraught can be countered by placing heaters under glass surfaces. Nowadays technology offers highly insulating windows, which is why there is an interest to investigate the indoor climate with only underfloor heating. The research in this area is limited, and few empirical methods are available.
Uppfattning om information avseende kost och fysisk aktivitet vid adjuvant behandling mot bröstcancer
Aim: To describe perceptions about written and verbal information regarding diet and physical activity in women with breast cancer and to study possible differences between ages and perception. Method: A cross-sectional study was conducted and consisted of 57 women with breast cancer stages I-III who started adjuvant chemotherapy within a year (2007-2008). A questionnaire, regarding their perceptions about the written and verbal information they had received about diet and physical activity, was responded to three months following treatment completion. Between 67-93 % of the participants responded to the questions. The answers was analyzed with descriptive statistics and Mann Whitney U-test.
Patientens akuta smärta underskattas av sjuksköterskan och läkaren
Smärta är en unik upplevelse som enbart den drabbade kan bedöma. I sjuksköterskans arbetsuppgifter på en akutmottagning ingår att se till varje patients unika behov. För att inte ett vårdlidande skall skapas för patienter med smärta är det viktigt att en korrekt behandling för smärtan ges. För att detta skall kunna ske krävs att sjuksköterskan på akutmottagningen, dels har god kunskap om smärtlindring dels vet hur smärta kan utvärderas på ett adekvat sätt. Syftet är att beskriva resultat från kvantitativa studier som undersökt överensstämmelse mellan patientens subjektiva smärtskattning av akut smärta och vårdpersonalens skattning av densamma.
Att spegla verkligheten - en studie av simuleringar i geografiundervisning på gymnasienivå
I arbetet görs ett försök att genom litteratur och elevintervjuer närma sig frågan om vilka förutsättningar för lärande som simuleringar i geografi erbjuder och vilka lärandeteorier som då blir relevanta. Intervjuer har därför gjorts med elever efter att de genomfört ett för undersökningen utvalt simuleringsspel. I arbetet ställs också frågan om hur elever uppfattar simuleringen som didaktiskt verktyg och ett antal svarskategorier struktureras. Slutsatserna är att lärandet i simuleringar i första hand tycks vara beroende av den egna praktiska erfarenheten, den sociala interaktionen mellan deltagarna och den emotionella laddningen. Elevernas uppfattningar av lärandeformen stödjer dessa kvalitéer, men tillfogade också betydelsen av variation i undervisningen och det inneboende spelrummets betydelse för kreativiteten..
DISPUTERAD OCH KLAR- ÄNDÅ INTE ANSTÄLLNINGSBAR. Personalens upplevelser av anställningstrygghet och karriärmöjligheter vid ett svenskt universitet
This study examines university employees? perception of their employment situation and career opportunities. By tradition, fixed term contracts are used in the Swedish research community due to dependency on insecure funding. There is a current debate that questions this use of insecure employments. The employments are said to negatively affect the university?s societal role and international competitiveness.
Chinese Remainder Theorem
Chinese Remainder Theorem is used to solving problems in computing, coding and cryptography. In computing we can compute with shorter numbers instead of large numbers and this will make the computing-process faster and easier. In coding it can be used for error-searching and error-regulating.Cryptography means that we can send a coded message and that no one will be able to read it without the decode-key which is based on prim-numbers. I am writing about the history of mathematics and how the number- and decimal number-system is used in Babylon, Egypt, Greece and in China. Abacus was a very important aid to calculate advanced mathematical problems.
Småskalig säsongslagring av solenergi för uppvärmning av bostäder : Simulering av lagerutformning och konsekvensen av adderade uppvärmningsbehov motsvarande en pool och ett atrium
The sun is a huge energy source with great potential of providing energy to the heating of homes and other buildings in an environmentally sustainable manner. In order to provide buildings with energy from the sun it is necessary to transfer the energy supply over time to when the demand arises. By storing the heat in a seasonal storage, solar energy from the summer can be used in the winter when the demand for heating is greatest.Today's existing plants are mainly in Europe and particularly in Germany. These facilities are designed to supply heat demands greater than 400 MWh and covers about 40-50 % of this need which consists of energy for space heating and domestic hot water. How much of the heat demand that is covered, the solar fraction, is partly due to losses from the storage which in turn is connected to the surface area of the storage.
Effektiv betong för småhusproduktion : Betong med högt luftinnehåll för platta på mark
This Masters thesis work describes a comparison between two different methods for estimation of the down channel (base station to mobile subscriber) in Wide-band Code Division Multiple Access (WCDMA). The first estimation method, Optimal Feed-forward Channel Estimation (OFCE), is a conventional method that bases the estimates on data that is known to both sender and receiver, so called pilots. The second method, Decision Directed Channel Estimation (DDCE), is an elaboration of OFCE. It also uses user data for estimation. Simulations show that DDCE, in comparison to OFCE, does not attain an improvement in signal-to-noise-ratio (SNR) for high bit error rates (BER).
Icke-linjära modelleringsteknikerav förspänd betongkonstruktion : Reaktorinneslutningen på Forsmark 3
A new material model, for the FE-program ADINA, has been verified against twoexperiments. One unreinforced concrete beam and one reinforced concrete beam.The model, DF-concrete, has the possibility to estimate true concrete. However theresults indicate that in order to be sure that the estimations are true, there ought tobe data from the true concrete to verify against.Two FE-models have simulated the behavior of a ring-shaped part of the nuclearcontainment vessel. The results from the first, frictionless, model agree with similarsimulations and hand calculations for high pressures in the containment vessel. Thesimulations of the nuclear containment vessel show cracking in the concrete after10-11 bars of over pressurization.
Modellering av rotationssystem
This master thesis was conducted during the spring of 2014 at Atlas Copco Rock Drills AB in Örebro. The purpose of the thesis was to develop a simulation model of the rotation system for a hydraulic rock drill. In the future, the model will be used to investigate the phenomena called ?jerky rotation?. In order to validate the simulation model a test bench was designed and tests were made.