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127 Uppsatser om Particle filtering - Sida 8 av 9
Biomass losses during short-term storage of bark and recovered wood
Storage of biomass is associated with problems like heat development, biomasslosses, and reduction of the fuel quality. Certain processes such as biological- andchemical degradation are responsible for these storage problems. This master?sthesis was carried out at Vattenfall Research and Development AB and is alignedtowards quantifying the biomass losses from short-term storage (1-2 months) ofbark and recovered wood. The biomass was stored in outdoor piles during differentseasons, campaign 1 (summer) and campaign 2 (autumn).
MCNP-modell för beräkning av neutrondos och DPA på reaktortanken vid Ringhals 2
In this report an MCNP (Monte Carlo N-Particle) model is described for the reactor vessel at Ringhals 2. The model is validated against the specific activity in neutron dosimeters, extracted in 1977, 1984 and 1994. The validation showed that the calculations of the model are within the requirements of a maximum of 20 percent uncertainty for every neutron dosimeter except one, extracted after the first cycle. The uncertainty of this cycle was mostly due to the operation data rather than to the MCNP model.The model has been used to investigate various questions concerning radiation damage. The reliability of the traditional measure of radiation damage, fast neutron flux (En > 1MeV) has been evaluated. This has been done by taking the ratio for this and another measure of radiation damage, DPA (Displacement Per Atom), for various positions and layers.
Mätning av Emissioner från en Diesel Motor under Transient Driftförhållande
Transient driftförhållande blir allt mer intressant för forskare och tillverkare och de största svårigheterna är att minska emissionerna utan att påverka bränsleförbrukningen eller motorns respons vid gaspådrag negativt. Huvudmålet med det här examensarbetet var utvärdera olika metoder för att mäta NOx och antal partiklar med hög tidsupplösning för att möjliggöra studier av emissioner under transient driftförhållande.I arbetet har en Horiba MEXA 120NOx NOx-sensor studerats med avseende på linearitet, mätsäkerhet och responstid. Försök för att öka noggrannheten har också gjorts genom att kompensera för varierande skalfaktor för utsignalen och för responstiden.Ett spädsytem har arbetats fram för att ge hög tidsupplösning och god repeterbarhet. I detta ingick en Rotating Disc spädare och en två-stegs Dekati spädare. Spädsystemet var kopplat till en TSI Ultrafine Condensation Particle Counter 3025 A (CPC) och var nödvändigt för att hålla koncentrationen inom det mätbara området.
Kvantfysiken och den nya myten? : En studie av Fritjof Capras och Danah Zohars böcker om kvantandlighet
This study is about quantum physics and the role it can play in a religious perspective. I intend to examine how moderna physics may be related and understood as New age and Myths. My material consists of two books in the new age genre: "The Tao of Physics" by Fritjof Capra and "The Quantum Self" by Danah Zohar. My first two question to these books are which 1) religious and 2) scientific content they have. My other questions are too 3) investigate and demonstrate how these books are new age and 4) to exanine how the books can function as myths and adopt mythical features.
Syntaxbaserad författarigenkänning
The writing style of a particular author can be divided into many subfeatures, for example use of words, language and syntax. Focusing on the latter, this study aims to show how well syntactic information alone can attribute the correct author to a document. Syntactic information is defined as overlapping syntactic subtrees of height one (1) for all sentences of all included documents. The performance is compared to that of the previously very successful method of comparing stop word frequencies. These are words normally excluded from search engine queries, because they are present in all sorts of texts regardless of topic.
En organisation för stor för sin egna kompetens : En kvalitativ forskningsstudie på polismyndigheten Värmlands internkommunikation
Denna uppsats behandlar ämnet internkommunikation. Vi har valt att genomföra en undersökning om Polismyndigheten Värmlands internkommunikation då de innehar ett stort ansvar att bevara trygghet och säkerhet i samhället. Polismyndigheten har även stora krav på sig idag gällande dialog och grad av kommunikation inom organisationen för att effektivisera det polisiära arbetet. Syftet med denna uppsats är att erhålla en insikt om den interna kommunikationens funktion och hur den gestaltas utifrån chefernas och de anställdas perspektiv. I denna uppsats använder vi oss utav relevanta teorier inom organisationskommunikation, internkommunikation, organisationsidentitet, organisationskultur och kommunikationsmodeller.
Hur uppnår vi god inomhusmiljö i förskolan idag?
Abstract:This thesis work has been conducted at the Real Estate Department in Halmstad.The department consists of a construction/project management-unit and an operation/management-unit.Like many other towns in Sweden, Halmstad has had a long lasting problem with indoor environment. Not at least at their preschools.Today they are constructing from current building regulations. They have learned from negative experiences which have occurred in the indoor environment in older buildings.Focus is now on healthy materials, like low emission value, energy efficiency and optimization of the building, but still with soft parameters such as cleaning, interior and choice of materials.The fixtures is provides by the real estate department and the furnishings are provides by the children and youth administration. Together they are trying to provide a great indoor environment.I have, together with the real estate department and the children and youth administration of Halmstad, investigated how to provide a good indoor environment in the preschools with small funds.In my thesis there is one theoretical part with a questionnaire survey of how the preschool staff is experiencing their indoor environment to determine where the problems often start. And a practical part with measurements to try and come down to a result that analysis the cause of the problems and also to make sure that the ventilation systems are fulfilling projected values.The measurements and the questionnaire surveys was made at Lokes preschool in Frösakull, Askens preschool in Oskarström and Gullbrandstorps preschool.There were some differences between the staff-responses at the three different preschools.At Askens preschool they feel that the premises are cleaned poorly.At Gullbrandstorps preschool they feel that the indoor-air is bad because they can´t open the windows.
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.
Punktmolnshantering i anläggningsprojekt : Utvärdering av programvaror för framtagande av markmodell
An increased number of participants in the construction industry is asking for accompanying terrain models to the project in order to get a better understanding of the field. When the desire to create buildings that fit together nicely with the surrounding area is increasing, it becomes more and more important to have a broad base of knowledge about the ground on which the building is to be erected. Terrain models are also very useful in the planning of logistics, documentation for landscape architecture projects, and billings for mass calculations.Surveys for creating terrain models can be performed with laser scanning. The advantage of laser scanning is the time-effective surveying, the detailed information as well as the ability of application in complex environments resulting in a cost-efficient project. With this in mind our thesis was defined in collaboration with the company Bjerking AB in Uppsala in order to investigate if there were any softwares suitable for terrain modeling.
Rekommendationssystem för interaktiva musiktjänster : en utredning av aktuella trender och attityder gentemot framtidens rekommendationssystem diskuterat ur forskar-, industri- & användarperspektiv
Parallel to new technological advancements, including the development of interactive recommender systems, digital music services on the Internet, such as Spotify, have in a short time span gradually replaced former physical media such as CDs and MP3-players and become pioneers on a market with an otherwise uncertain future. By subscribing to the service, users have access to a vast library of music and from any device with Internet access. In order to provide a satisfactory and useful musical experience, different ways of coping with the vastness is required - which is precisely what recommender systems are for. Improved filtering techniques and use of devices built in sensors, make way for new opportunities of more precise and contextually tailored suggestions for track selection, which in turn leads to potential privacy issues when using interactive music services. But where do we stand today? By compiling, exemplifying and discussing three different perspectives with relating to the development of interactive music recommender systems, the objective for this paper is to provide a for science, industry and user, objectively nuanced account of current potentials and expectations.
Utveckling av en LC-MS-metod för analys av gamma-hydroxibutyrat, gamma-butyrolakton, 1,4-butandiol, amfetamin och metadon
In this project a LC-MS-method for the analysis of gamma-hydroxybutyrate, gamma-butyrolactone, 1,4-butanediol, amphetamine and methadone was developed.Initially, the efficiency of the ionisation of the analytes was evaluated with respect to the ionisation technique (ESI, APCI and APPI) and the composition of the mobile phase. In the next step a number of different columns was tested in order to find the one with the greatest potential for separation of the substances in question. Using the selected column, the separation was optimised by means of experimental design and the software The Unscrambler 7.8. The parameters studied were the flow rate, the column temperature and the mobile phase composition. The response variables were the resolution between the target compounds and the retention time of the last eluting compound.These experiments showed that, in order to obtain the best ionisation, the mobile phase should consist of 5 mM formic acid in water and acetonitrile.
Energy efficient storage of biomass at Vattenfall heat and power plants
Storage of biomass is often associated with problems such as heat development, dry
matter losses and reduction of fuel quality. The rise in temperature can potentially
cause a risk of self-ignition in the fuel storage. Moreover, emissions from storage piles
can cause health problems in the surrounding. The dry matter losses and reduction of
fuel quality can have economical effects. The aim of this thesis project is to develop
guidelines on how to store large amount of biomass at Vattenfalls heat and power
plants in an optimal way.
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.
Kalkningens påverkan på fosforlöslighet : skakförsök baserade på två svenska långliggande kalk- och fosforgödslingsförsök
Eutrophication is an environmental problem that affects more than ten percent of Swedish lakes. Excess nutrients increase the growth of algae, and cause major problems in the ecosystem through oxygen-free bottoms, fish kills, and at worst dead bottoms. Agriculture accounts for 44% of human emissions of phosphorus to lakes and rivers. Leaching occurs of particle bound phosphorus and of dissolved
phosphate. The amount of phosphate in the soil solution that may be leached is partly due to the prevailing pH in the soil solution.
The purpose of this study was to investigate how the relationship between phosphate solubility and pH was affected by liming.
Modellering och styrning av flis till en sulfatkokare
At the Skoghall pappermill, sulphatepaper pulp is produced in a continuous digester originally from 1969. To be able to maintain a high level of production there is a need for a process with few disturbances. Variations in how well the wooden chips are packed in the digester is one form of disturbance. Today there are no available measurements on how well the chips are packed. Instead this is regarded as being constant.