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11681 Uppsatser om Emission data - Sida 14 av 779
Utveckling av en Multi-Zonsmodell för NOx Bildning i Diesel Motorer
This thesis work is the last part of the Master of Science education inmechanical engineering at KTH, Stockholm.The aim of this project was the development of a Multi-zone modelfor NOxformation in Diesel engines. Because of the stringent emissionlegislations, great effort is made to decrease the fuel consumption and theharmful emissions of internal combustion engines. Computer simulationsplay a decisive role in this context because they substitute the expensiveand time-consuming laboratory tests.The model is based on a multi-zone approach and uses the wellknownExtended Zeldovich Mechanism which gives a relation to calculatethe NO formation rate using the concentration of different gas speciesinvolved in the process.All the most important phenomena involved in the Diesel combustionhave been modelled. A special attention is then paid to the equilibriumconcentration calculation; this is a significant part of the model whichstrongly influences the following steps.A Simulink model has also been developed. This second version isbased on the previous model and it is made especially to allow theconnection with other external softwares, GT-power in this case.
Metoder för kartläggning och analys av nätförluster i lågspänningsnät
An important process for grid companies in order to reduce power losses in electricity distribution grids is to figure out where and how they appear. This report describes the factors that cause power losses in low voltage distribution grids and methods for how they could be measured and analyzed. Measurement data for consumed and injected energy were collected for twelve low voltage distribution grids owned by Gävle Energi AB in order to analyze the size of the power losses and how the measurement uncertainty affects the collected data. Then models of three of the grids were created in MATLAB in order to analyze the data and the power losses were calculated to be compared to the collected data. Curve fitting were also used as a method in order to analyze the power losses from collected data.The results show that the losses in the studied grids are low.
Dagvattensystem i järnbrott - Reducering av trycknivåer mha fördröjningsmagasin
IP-adresserna under IPv4 är inte tillräckliga och har på många delar i världen redan tagit slut. IPv6 erbjuder många fler tillgängliga adresser och övergången till protokollet har redan börjat. Det Gävlebaserade företaget Interlan erbjuder en tjänst som kontrollerar om kommuner och myndigheter i de nordiska länderna är nåbara via IPv6 samt om de är säkrade med DNSSEC. Denna rapport beskriver jobbet med att förbättra och göra deras tjänst anpassningsbar för flera länder. Processen som beskrivs är parametriseringen av skripten som samlar data, skapandet av en databas att lagra data i, och ändringar till hur data presenteras så att det går att lägga till flera länder..
Miljöarbete inom den civila luftfarten
The main environmental problem for aviation is the great amount of exhaust gases, mainly nitrogen oxides, carbon monoxide, carbon dioxide and hydrocarbons - mostly "greenhouse gases" leading to climate changes. I decided to sort out what is being done to decrease these problems and what regulations there are concerning air pollution by the means of searching the internet and using publications from aviation authorities for current figures. I chose to scrutinize authorities on political, authority and company level, resulting in summarizing the work of UN and EU respectively, ICAO (International Civil Aviation Organization), JAA (Joint Aviation Authorities) and LFV (Swedish Civil Aviation Authority), and finally SAS, representing the airline companies. Conclusion that I have drawn are thatthere are regulations for air pollution, written down in ICAO's Annex 16, that are to be followed. Secondly, LFV are environmentally controlling their nineteen airports and since economy is an important reason for not giving priority to environmental issues in aviation emission charge and noise charge are added to the landing fees.
Termisk hantering av litium-jon- batterier i elektriska drivsystem
The automotive market is currently undergoing a historical change where stricter emission legislations and ever increasing fuel costs have intensified the search for effective alternatives to the conventional internal combustion engine, which has resulted in a substantial trend towards electrification of powertrains. Storage of electrical energy is the fundamental component in this technology where the lithium-ion batteries are currently considered as the most appropriate solution. Lithium-ion batteries, however, as other types of batteries, can only be used efficiently and durably within a specific temperature range.This Master thesis has been carried out in collaboration with Electroengine in Sweden AB, situated in Uppsala, which has an ongoing project regarding development of a modular battery system for electric powertrains. The project is at a stage where an initial prototype has been developed which provides the foundation for this thesis. The study has addressed the battery system performance from a thermal perspective, in order to validate the ability of the system to create a thermally serviceable environment for the lithium-ion battery cells.
Fördröjning och bortfall av nätverkskorrektioner : osäkerhetskällor för nätverks-RTK
Network RTK is a real-time technique for accurate positioning with Global Navigation Satellite Systems (GNSS). The technology means the use of correction data from a network of GNSS receivers with known positions (reference stations) to reduce the uncertainty in position for the user´s GNSS receiver (rover). However, this requires that the correction data can be transferred seamlessly to the user in real time. Commonly the corrections are transferred via mobile phones. The Swedish National Land Survey operates a nationwide Network RTK service, where users can receive correction data via GSM or mobile Internet (GPRS).
Studier av nitreringskinetiken för järn-kromlegeringar i
ammoniak-vätgasmiljö
Kinetiken för nitrering av en järn-kromlegering med en gasblandning av ammoniak och vätgas har studerats vid temperaturer mellan 500°C och 600°C. För ett gasatomiserat pulver (Fe-7%Cr) har inverkan av syrepotential (H2O/ H2) och olika förbehandlingar (förreduktion och förnitrering) studerats med hjälp av en termogravimetrisk metod. Dessutom har laserablering som förbehandlingsmetod för nitrering av solida ytor studerats med hjälp av GD-OES-analys (Glow Discharge Optical Emission Spectrometry). Resultaten har diskuterats och tolkats med avseende på faktorer som kan påverka ytreaktionens hastighet, kärnbildningsförhållanden samt diffusionsvillkor. Syrepotentialen har visats påverka nitreringshastigheten via komplicerade samband mellan syrepotentialens storlek, kvävehalt i materialet och nitreringstemperatur.
Ljusspridningsvariationer i finpapperstillverkning
The purpose of this Master's thesis is to find possible explanations of variation in light scattering in a fine paper. Samples were collected from each second tambour during a time period of two weeks from a paper machine at MoDo Paper, Husum. Two data sets, consisting of 20 and 95 observations, were selected for extensive analysises of tensile and structual properties. The data was evaluated with multivariate data techniques using the programs Simca and Extract. The results of PCA- and PLS- analysises pointed out 3 of 52 variables as important for the variations in light scattering.
Identifiering av röjningsbestånd med hjälp av flygburen laserskanning
Bergvik Skog is one of the leading forest companies in Sweden who use airborne laser scanning for forestry information. They utilize laser data retrieved by the Swedish National Land Survey to describe the forest holdings and facilitate planning for thinning and final felling operations. However, the possibility to identify stands with clearing needs by using laser scanning data has not been tested in a large scale. The data used in the current study are field data from The Swedish National Forest Inventory in combination with laser data from the Swedish National Land Survey acquired in 2009. The collected data is used to find one or several laser variables that best describe the relationship of the field measured samples with clearing needs.
Studie av belagda kolvringarmot plasmasprutat cylinderfoder : Med avseende på friktion och nötningsmotstånd
Future emission legislation puts great emphasis on increasing the efficiency of the engine, thereby reducing fuel consumption. The tribological contact between cylinder liner and piston ring is where an great amount of energy is lost due to friction, and by reducing these losses an reduction in fuel consumption can be achieved.The aim of this thesis was to evaluate the tested piston ring coatings against a plasma sprayed cylinder liner and rank these combinations of materials for friction and wear resistance. The coatings that were tested was Cr + Al2O3, (Al,Cr)N, two types of CrN and WC / C.The experimental tests were performed with a so-called pin-plate, where used oil with addition of an acidic mixture of sulfuric and nitric acid to mimic the acidic condensate formed when exhausts recirculate, were added with a continuous flow. The results were then analyzed by weighing, studies by optical microscopy and scanning electron microscopy (SEM) and profile measurements.The results from each material combination were that the plasma coated cylinder liner wears too aggressively in order to yield a ranking of the piston ring coatings based on the parameters of friction and wear resistance. It is therefore proposed that an alternative coating on the cylinder liner should be developed, lacking the large abrasive wear on piston rings and that can withstand the corrosive environment resulting in engines equipped with EGR.
Deduplicerings påverkan på effektförbrukningen : en studie av deduplicering i ZFS
Uppsatsen beskriver arbetet och undersökning för hur deduplicering i filsystemet ZFS påverkar effektförbrukningen. En större mängd redundant data förekommer i centraliserade lagringssystem som förser virtualiserade servrar med lagringsutrymme. Deduplicering kan för den typen av lagringsmiljö eliminera redundant data och ger en stor besparing av lagringsutrymme. Frågan som undersökningen avsåg att besvara var hur ett lagringssystem påverkas av det extra arbete som det innebär att deduplicera data i realtid.Metoden för att undersöka problemet var att utföra fem experiment med olika typer av scenarion. Varje scenario innebar att filer kopierades till ett lagringssystem med eller utan deduplicering för att senare kunna analysera skillnaden.
Gallringsinventering från helikopter utrustad med profilerande laser och kamera för låghöjdsfotografering
Today Holmen Skog finds and selects suitable thinning stands using data on upper height and basal area. These figures are often based on basic forest data that has been updated with the help of growth prediction models. The problem is that these figures are not always correct. The aim of this study was to investigate if a combination of data from a profiling laser and a digital camera for low elevation photography, can be used for collecting data on number of stems per ha, tree species mixture as well as basal area weighted mean height and upper height for stands. The possibility to use these data to assess the need for thinning cutting was also investigated.Laser data and aerial photographs were collected from a helicopter operating at an approximate height of 100 meters.
Implementation av Microsoft Exchange ActiveSync mot en molntjänst
This report describes a bachelor thesis work performed at the cloud storage company CloudMe in Linköping, Sweden. The storage service provided by CloudMe allows users to access their files seamlessly from multiple units at the same time. In the cloud there is storage provided for contacts, calendar and e-mail, which is data nowadays normally used by smart phones.Exchange ActiveSync is a protocol developed by Microsoft which, among much more, provides functionality to synchronize the previously described data. This protocol is supported by the smart phone developers and the ability to synchronize over the exchange protocol is implemented in products by default. Due to this fact it would be preferable to implement support for synchronization from CloudMe to phones over this protocol.
Metadatadriven transformering mellan datamodeller
För att flytta information från en databas till ett datalager används det idag olika tekniker. Existerande transformeringstekniker baseras på att en applikation hanterar detta. Detta examensarbete går ut på att skapa och undersöka en metod som istället genomför transformeringen i en databas. Denna transformering är metadatadriven, eftersom metadata är den information om data som krävs för att en transformering ska vara möjlig. Arbetet bygger därför på en metadatastudie som behandlar representation och struktur av metadata.
Mjölkureahalten som mått på vommikrobernas kväveförsörjning och kons miljöbelastning
The aim of this literature study was to analyze how milk urea concentration is working as a measure of the nitrogen supply to rumen microbes and indicator of the environmental load. Questions included in this literature study were how to improve the dairy cattle nitrogen efficiency and what correlations there are between milk urea, nitrogen efficiency and crude protein content in the feed. Effects on the reproduction from high ration protein content are also addressed. Dairy cattle are today fed with large proportions of protein which could lead to high expenditure of feed and environmental pollutions. The nitrogen can be lost to the environment by different pathways; leaching, denitrification or by emission to the air.