Laser Diagnostic Techniques with Ultra-High Repetition Rate for Studies in Combustion Environments

When conducting laser based diagnostics in combustion environments it is often desirable to obtain temporally resolved information. This can be due to several factors such as combustion taking place in a turbulent flow field, flame propagation from a spark plug in an initially quiescent combustible mixture, or rapid, multi-point fuel consumption in a homogeneous charge as a result of compression ignition in an engine cycle. A multi-YAG laser cluster and a high-speed framing camera capable of recording sequences of up to eight image frames, and having a framing rate up to the megahertz range were originally set up for these types of studies. Within the framework of this thesis, further developments of this high-speed diagnostic system aiming at extending the wavelength palette and thus the range of detectable species, was carried out. In addition, the system was used for measurements with ultra-high repetition rates for the detection of different flame species in a variety of combustion devices. The high-speed laser system was redesigned for the generation of laser radiation at 355 nm, in addition to the original 532 nm and 266 nm, and a successful feasibility test for high-speed formaldehyde planar laser-induced fluorescence (PLIF) was carried out for the new design. Moreover, a novel multi-dye laser cluster has been set up. By pumping each of the four dye lasers individually using the Nd:YAG lasers in the multi-YAG cluster, tunable laser radiation with an ultra-high repetition rate can be produced, without the drawback of either losses in laser pulse energy or significant deterioration of the beam intensity profile often occurring when a single dye laser is pumped at ultra-high repetition rates. The multi-YAG and multi-dye laser clusters were used for high-speed visualization of the OH radical by means of planar laser-induced fluorescence in a low-swirl methane/air flame for tracking flame front movements over time while simultaneously measuring the flow-velocity field. Simultaneous high-speed OH visualization and imaging of the temperature field was also performed. The work carried out was a first step in the development of a detailed Large Eddy Simulation validation database for turbulent, premixed methane/air flames. High-speed OH PLIF using a single dye laser was employed in several other studies of the reaction zone, including an investigation of the ignition properties of hot jets in explosive environments, a study of combustion processes in a pulse combustor, and an investigation of the governing processes leading to electrical signals in an ion-current sensor. The last of these also included high-speed fuel tracer LIF. An alternative technique for flame studies involving measurement of the chemiluminescence from OH and CH in order to determine the equivalence ratio was investigated in terms of spatial and temporal resolution. The capability of the technique for resolving flame fronts was compared to reference measurements of OH PLIF. The tests showed that the spatial resolution in the depth direction suffered from line-of-sight detection, which significantly reduced the resolution. As the sensor was designed for monitoring spatial and temporal inhomogenities in mixtures within industrial gas turbine combustors, the temporal and spatial scales in such a combustor were evaluated using the high-speed laser diagnostic system for time-resolved visualization of OH. Also, fuel tracer PLIF was performed in order to visualize the fuel distribution in the combustor. The multi-YAG laser cluster was used in several studies of combustion processes in a homogeneous charge compression ignition (HCCI) engine, involving both high-speed fuel tracer PLIF and formaldehyde PLIF, with the aim of studying different types of ignition control. Acetone was used as a fuel tracer in investigating the effects of combustion chamber geometry on combustion. In studies of spark-assisted HCCI operation, the engine was run on a fuel mixture containing n-heptane, which produces formaldehyde early in the cool-flame region. Formaldehyde can thus be used as a fuel marker, eliminating the need of an added fuel tracer in this situation. Furthermore, three-dimensional imaging of formaldehyde in a laboratory flame as well as of Jet-A vapour in a slow non-reacting flow was demonstrated. This was achieved by rapidly scanning the laser sheet across a measurement volume spatially separating the eight laser pulses. A stack of closely spaced PLIF images was acquired by the framing camera, which could be used to re-create the three-dimensional shape of the investigated species by means of interpolation between the sheets

High-Speed LIF Imaging for Cycle-Resolved Formaldehyde Visualization in HCCI Combustion

High-speed laser diagnostics was utilized for singlecycle resolved studies of the formaldehyde distribution in the combustion chamber of an HCCI engine. A multi- YAG laser system consisting of four individual Qswitched, flash lamp-pumped Nd:YAG lasers has previously been developed in order to obtain laser pulses at 355 nm suitable for performing LIF measurements of the formaldehyde molecule. Bursts of up to eight pulses with very short time separation can be produced, allowing capturing of LIF image series with high temporal resolution. The system was used together with a high-speed framing camera employing eight intensified CCD modules, with a frame-rate matching the laser pulse repetition rate. The diagnostic system was used to study the combustion in a truck-size HCCI engine, running at 1200 rpm using n-heptane as fuel. By using laser pulses with time separations as short as 7

Att plaska i vatten. Kommunala grundskolors simundervisning i Göteborg, inriktad på årskurserna 5-9

Bakgrund Under vår tid som studerande, på vår Verksamhetsförlagda utbildning och under våra första år som idrottslärare har vi fått erfara att ekonomiska frågor ofta styr hur simundervisningen bedrivs och att simundervisningen skiljer sig mellan olika skolor. Detta har lett till en nyfikenhet hos oss. Vi vill se hur det fungerar med simundervisningen på andra grundskolor i Göteborgs kommun. Syftet med undersökningen är att få en bild över ett antal kommunala grundskolors definition på simkunnighet i Göteborgs kommun. Syftet är även att se vad som görs för de elever i årskurs 5-9 som inte uppnår målen i momentet simning, samt ge en bild över hur simundervisningen finansieras och hur det är med simkunnigheten hos eleverna på de undersökta grundskolorna. Metod Vi har använt oss av enkäter, kompletterande intervjuer och deltagandeobservationer. Enkätundersökningen skickade vi ut till 4 stycken kommunala grundskolor i Göteborgs kommun. Intervjuerna var av kompletterande art och till för att minska bortfallet i undersökningen. Undersökningens totala bortfall var fyra stycken enkätsvar. Dessa fyra bortfall bestod av två stycken F-5 skolor, en F-9 skola samt en 6-9 skola. Dessa besvarade aldrig enkäten. Det förekommer bortfall på vissa frågor. Den deltagande observationen gjorde vi under ett simtest för alla femteklasser på en skola. Resultat Vi fann att definitionen av att vara simkunnig skiljde sig i många avseenden bland de skolor vi frågade. Dock såg vi också att den vanligaste definitionen av att vara simkunnig är den definition som formulerats med hjälp av Svenska Livräddningssällskapet. Vad som görs för de elever som inte når upp till målen i simning skiljde sig. Majoriteten av de undersökta skolorna erbjuder extra stöd för sina elever i simundervisningen. Dock finns det skolor som inte erbjuder någon simundervisning till dessa elever. Vår undersökning visade att det skiljer sig mellan skolorna hur simundervisningen finansieras. Enligt undersökningen står majoriteten av skolorna för kostanden. Vår enkätundersökning pekar på att det finns oroväckande många elever som går ut årskurs fem och som inte uppnått målen för simkunnighet

Sol, sand, surf och sex : En kvalitativ postkolonial diskursanalys om den mediala turismrapporteringen från Haiti och Dominikanska Republiken

The essay is about how Swedish media have chosen to report on tourism from Haiti and the Dominican Republic in 1993-2018. There may be many different aspects to look into within this but the aspects that have been studied are the degree to which nature and culture are seen in this reporting. The analysis of the articles of the newspaper Dagens Nyheter has been made based on a postcolonial discourse analysis where certain postcolonial concepts have been applied to the selected articles. It is in what ways the different writers have chosen to describe the nature and culture of the two countries that have been analyzed and an analysis will be made of whether reporting differs between the countries. The result shows that the writers are clearly governed by a Eurocentric world order where We, Europe, have a clear overarching relationship in relation to Them, Haiti and the Dominican Republic, who have a clear subordination. This clear boundary is clearly visible in the words chosen by the writers by normalizing concepts that are under the category We and nonnormalizing concepts that belong to Them. The conclusion is that Haiti is described in a lesser way than the Dominican Republic, which may be because Haitians are more strange to us than Dominicans depending on the countries different histories where the Haitians are seen as a Creole language speaking African society and the Dominicans are seen as a Spanish speaking European society.Uppsatsen handlar om på vilket sätt som svenska medier har valt att rapportera om turism utifrån länderna Haiti och Dominikanska Republiken under åren 1993-2017. Det kan finnas många olika aspekter att kolla på inom detta men de aspekter som det har studerats om är i vilken grad som natur och kultur syns i denna rapportering. Analyseringen av Dagens Nyheters tidningsartiklar har gjorts utifrån en postkolonial diskursanalys där vissa postkoloniala begrepp har applicerats på de valda artiklarna. Det är på vilka sätt som de olika skribenterna har valt att beskriva naturen och kulturen i de båda länderna som har analyserats och det kommer att göras en analys på om rapporteringen skiljer mellan länderna. Resultatet visar att skribenterna är tydligt styrda i en eurocentrisk världsordning där Vi, Europa, har en tydlig överordning jämfört med De, Haiti och Dominikanska Republiken, har en tydlig underordning. Denna tydliga gränsdragning syns tydligt i de ordval som skribenterna gör genom att normalisera begrepp som är under kategorin Vi och icke-normalisera begrepp som tillhör De. Slutsatsen är att Haiti beskrivs på ett undermåligare sätt än Dominikanska Republiken som kan bero på att haitier är mer främmande för oss än vad dominikaner är beroende på att de sistnämnda passar in mer under kategorin Vi

Positionell diskriminering på fotbollsplanen : En studie om fenomenet stacking i 2017 års säsong av Herrallsvenskan i fotboll jämfört med 2012 års upplaga

Sports in general and football in particular have often been considered a good arena for integration, all of which should be of equal value and not discriminated because of, for example, their ethnicity or skin color. In this study, I have tried to look at the phenomenon stacking, disproportionate division of positions, existing in Allsvenskan during the 2017 edition, thus revealing whether there is discrimination in this elite race. It was found that stacking still occurred in Allsvenskan in 2017 but since the essay has been made in comparison with a similar study from 2012, it has turned out that stacking has now become a lesser issue in Swedish football. Why stacking has diminished may be due in part to the struggle of various non-profit organizations and the Swedish Football Association for increased integration

Weak concepts as direction of operation : A study of how Tillväxtverket’s project Stronger local appeal for municipalities has been translated on local level

The overall aim of this essay has been to study how Swedish municipalities translate politics to hands-on action. More specifically by analysing how participating pilot municipalities within Tillväxtverket’s project Stronger local appeal in effect translated the project to local efforts. A second, underlying, aim was to identify the local projects understanding of fundamental but inadequately defined concepts included in the policy they were translating. This was done through a qualitative interview research approach with the pilot project leaders from each participating municipality. The empirical data was analysed through thematical analysis. The study concludes that the project leaders’ interpretation and understanding of fundamental concepts vary. The understanding of method, bond to be developed by the participating pilots, was lacklustre. Appeal within municipalities, however, was generally interpreted to be varying different things, e.g. conflicting focus on already existing occupants versus attracting new ones. Analysis show that local efforts had a few different themes, establishing central groups with focus on the constellation of the group as well finding the right dialogue with or to whomever was targeted, was one. Working with different types of plans and strategies or visualizing what you as a municipality can offer presumptive developers, to mention a few others. Generally speaking, translation helps the study explain that there is no right or wrong in the different types of local efforts, as also proven by the many type of different themes and local efforts. Further research should focus on why the national level use weak concepts as direction of operation, the intention of it specifically.En examination, inte en presentation.</p

Quality assurance – An investigation about self-inspections in the design phase

I de flesta kvalitetsledningssystem som företag inom byggbranschen använder sig av idag finns krav på projektörer att utföra och dokumentera egenkontroller på handlingar. Detta för att kvalitetssäkra handlingar för att upprätta en bättre kundrelation. Utan utförda egenkontroller finns inget som styrker att handlingar verkligen är upprättade enligt gällande regler och normer vilket försvårar arbetet för konsulter vid reklamation. TM Konsult arbetar i dagsläget med kvalitetssäkring på en rad olika sätt. Företaget bedömer dock att arbetet med egenkontroller för att säkra kvalitén av handlingar kan förbättras. De hävdar att en bättre och tydligare rutin om hur egenkontroller ska användas bör utvecklas. På grund av detta vill TM Konsult undersöka hur arbetet med kvalitetssäkring av bygghandlingar kan förbättras och skräddarsys för just de anställda på företaget. Syftet med studien är att förbättra arbetet med egenkontroller vid kvalitetssäkring av bygghandlingar. Målet med studien är att komma med förslag på hur arbetet med kvalitetssäkring av bygghandlingar kan förbättras, där ett antal av förslag ska verkställas genom uppdatering av befintlig checklista. För att uppnå resultatet har en litteratur­studie och en fall­­studie utförts. I fallstudien intervjuas flera anställda på företaget genom semistrukturerade intervjuer. Studien påvisar tydligt att alla anställda använder sig av egenkontroller förutom när projekten är små. Åsikterna går isär när det handlar om hur de anställda ser på checklistans uppbyggnad, där flera anser att listan är bra medan andra hävdar att den är för utdragen. Flera hävdar att utföra egenkontroller är trist, dels på grund av en tungarbetad checklistan, dels för avsaknaden av påminnelser. Respondenterna presenterar problem inom organisa­tionen, avsaknaden av egenkontroller i tidiga skeden och programvaran som checklistan är upprättad i. De förslag som presenteras i studien grundar sig i de anställdas åsikter och idéer. När det gäller uppbyggnaden av checklistan är förslagen bland annat att byta programvara till Microsoft Excel, upprätta listan med trädstruktur och krympa listan genom att slå ihop checkpunkter. Vid förbättringar angående arbetet med egenkontroller föreslås bland annat att förbättra samordningen mellan chefer på olika orter, etablera kontinuerliga påminnelser, och förse anställda med utbildning. Två förslag på uppdatering av checklistan presenteras där alternativen är minskad i omfång och delvis upprättad med en trädstruktur. Såvida de förslag som presenteras implementeras finns förhoppningar om att arbetet med kvalitetssäkring av bygghandlingar ska kännas motiverande för de anställda. Resultatet ska förhoppningsvis på sikt generera en tydlig och begriplig rutin för hur kvalitetsarbetet ska utföras, som är lätthanterlig för de anställda. Det befaras dock att programvaran för att erhålla en fullständig trädstruktur bäst lämpar sig i en onlinetjänst som upprättas av en dataprogrammerare. Svårigheten för människor att granska och åtgärda sina egna fel och misstag riskerar också att påverka inverkan av förslagen. Förmodligen åtgärdas problemet när varje enskild individ identifierar och börjar använda det mest optimala tillvägagångssättet för just dem. Det är dock viktigt att förutsättningarna för detta finns hos företaget med tydliga rutiner och lättarbetade checklistor.

Weak concepts as direction of operation : A study of how Tillväxtverket’s project Stronger local appeal for municipalities has been translated on local level

The overall aim of this essay has been to study how Swedish municipalities translate politics to hands-on action. More specifically by analysing how participating pilot municipalities within Tillväxtverket’s project Stronger local appeal in effect translated the project to local efforts. A second, underlying, aim was to identify the local projects understanding of fundamental but inadequately defined concepts included in the policy they were translating. This was done through a qualitative interview research approach with the pilot project leaders from each participating municipality. The empirical data was analysed through thematical analysis. The study concludes that the project leaders’ interpretation and understanding of fundamental concepts vary. The understanding of method, bond to be developed by the participating pilots, was lacklustre. Appeal within municipalities, however, was generally interpreted to be varying different things, e.g. conflicting focus on already existing occupants versus attracting new ones. Analysis show that local efforts had a few different themes, establishing central groups with focus on the constellation of the group as well finding the right dialogue with or to whomever was targeted, was one. Working with different types of plans and strategies or visualizing what you as a municipality can offer presumptive developers, to mention a few others. Generally speaking, translation helps the study explain that there is no right or wrong in the different types of local efforts, as also proven by the many type of different themes and local efforts. Further research should focus on why the national level use weak concepts as direction of operation, the intention of it specifically.En examination, inte en presentation.</p

Positionell diskriminering på fotbollsplanen : En studie om fenomenet stacking i 2017 års säsong av Herrallsvenskan i fotboll jämfört med 2012 års upplaga

Sports in general and football in particular have often been considered a good arena for integration, all of which should be of equal value and not discriminated because of, for example, their ethnicity or skin color. In this study, I have tried to look at the phenomenon stacking, disproportionate division of positions, existing in Allsvenskan during the 2017 edition, thus revealing whether there is discrimination in this elite race. It was found that stacking still occurred in Allsvenskan in 2017 but since the essay has been made in comparison with a similar study from 2012, it has turned out that stacking has now become a lesser issue in Swedish football. Why stacking has diminished may be due in part to the struggle of various non-profit organizations and the Swedish Football Association for increased integration

Weak concepts as direction of operation : A study of how Tillväxtverket’s project Stronger local appeal for municipalities has been translated on local level

The overall aim of this essay has been to study how Swedish municipalities translate politics to hands-on action. More specifically by analysing how participating pilot municipalities within Tillväxtverket’s project Stronger local appeal in effect translated the project to local efforts. A second, underlying, aim was to identify the local projects understanding of fundamental but inadequately defined concepts included in the policy they were translating. This was done through a qualitative interview research approach with the pilot project leaders from each participating municipality. The empirical data was analysed through thematical analysis. The study concludes that the project leaders’ interpretation and understanding of fundamental concepts vary. The understanding of method, bond to be developed by the participating pilots, was lacklustre. Appeal within municipalities, however, was generally interpreted to be varying different things, e.g. conflicting focus on already existing occupants versus attracting new ones. Analysis show that local efforts had a few different themes, establishing central groups with focus on the constellation of the group as well finding the right dialogue with or to whomever was targeted, was one. Working with different types of plans and strategies or visualizing what you as a municipality can offer presumptive developers, to mention a few others. Generally speaking, translation helps the study explain that there is no right or wrong in the different types of local efforts, as also proven by the many type of different themes and local efforts. Further research should focus on why the national level use weak concepts as direction of operation, the intention of it specifically.En examination, inte en presentation.</p