Pinch-menetelmän soveltaminen sellutehtaassa

Työn tarkoituksena oli tutkia pinch-menetelmän soveltuvuutta toiminnassa olevassa UPM-Kymmene Oyj:n kaukaan sellutehtaassa ja kartoittaa pinch-analyysin avulla keittämön sekä haihduttamon lämpöenergiatarpeet sekä ylijäämät kesä ja talvitilanteissa vuodelle 1999. Kesätilanteeksi on katsottu riittävän elokuu ja talvitilanteeksi helmikuu. Työn alussa on lyhyesti käyty läpi pinch-tekniikkaan liittyvää teoriaa ja tutustutaan yleisesti työssä käytettyyn Pro_pi2 laskentaohjelmaan. Laskennan tulokset on muodostettu käsittelemällä tiedonkeruujärjestelmistä haettu virtaavien nesteiden tulo- ja kohdelämpötiloista sekä massavirroista muodostuva data Pro_pi2 laskentaohjelmalla. Tulokset on esitetty kappaleessa 5, jossa kesä ja talvitilanteista saatuja tuloksia on verrattu keskenään. Mielenkiinnon vuoksi mukaan vertailuun on otettu vuoden 1999 tietojen lisäksi myös tiedot vuoden 2000 talvelle. Pinch-menetelmään perustuvan Pro_pi2 laskentaohjelman todettiin soveltuvan ennemminkin lämmön talteenottojärjestelmän sekä tehtaan energiakäytön esisuunnitteluun kuin jo olemassa olevan tehtaan tutkimiseen.

Water consumption and soil moisture distribution in melon crop with mulching and in a protected environment

Mulching has become an important technique for land cover, but there are some technical procedures which should be adjusted for these new modified conditions to establish optimum total water depth. It is also important to observe the soil-water relations as soil water distribution and wetted volume dimensions. The objective of the present study was to estimate melon evapotranspiration under mulching in a protected environment and to verify the water spatial distribution around the melon root system in two soil classes. Mulching provided 27 mm water saving by reducing water evaporation. In terms of volume each plant received, on average, the amount of 175.2 L of water in 84 days of cultivation without mulching, while when was used mulching the water requirement was 160.2 L per plant. The use of mulching reduced the soil moisture variability throughout the crop cycle and allowed a greater distribution of soil water that was more intense in the clay soil. The clayey soil provided on average 43 mm more water depth retention in 0.50 m soil deep relative to the sandy loam soil, and reduced 5.6 mm the crop cycle soil moisture variation compared to sandy loam soil.

Characteristics of 2D convective structures in Catalonia (NE Spain): an analysis using radar data and GIS

Flood simulation studies use spatial-temporal rainfall data input into distributed hydrological models. A correct description of rainfall in space and in time contributes to improvements on hydrological modelling and design. This work is focused on the analysis of 2-D convective structures (rain cells), whose contribution is especially significant in most flood events. The objective of this paper is to provide statistical descriptors and distribution functions for convective structure characteristics of precipitation systems producing floods in Catalonia (NE Spain). To achieve this purpose heavy rainfall events recorded between 1996 and 2000 have been analysed. By means of weather radar, and applying 2-D radar algorithms a distinction between convective and stratiform precipitation is made. These data are introduced and analyzed with a GIS. In a first step different groups of connected pixels with convective precipitation are identified. Only convective structures with an area greater than 32 km2 are selected. Then, geometric characteristics (area, perimeter, orientation and dimensions of the ellipse), and rainfall statistics (maximum, mean, minimum, range, standard deviation, and sum) of these structures are obtained and stored in a database. Finally, descriptive statistics for selected characteristics are calculated and statistical distributions are fitted to the observed frequency distributions. Statistical analyses reveal that the Generalized Pareto distribution for the area and the Generalized Extreme Value distribution for the perimeter, dimensions, orientation and mean areal precipitation are the statistical distributions that best fit the observed ones of these parameters. The statistical descriptors and the probability distribution functions obtained are of direct use as an input in spatial rainfall generators.

Fluoriditasetarkastelu ja päästöjen hallinta ferrokromi- ja terästeollisuudessa

Työn alkuosassa kartoitettiin AvestaPolarit –yhtiöiden Tornion tehtaiden keskeiset fluoridilähteet kuten fluspaatti, valukuonat, valupulverit ja fluorivetyhappo. Valupulverien ja kuonien haihtumis- ja liukoisuuskäyttäytymistä valaistiin kotimaisten ja kansainvälisten tutkimusten avulla. Tutkimustuloksia sovellettiin pääpiirteittäin Tornion tehtaiden tilanteeseen ottamalla huomioon tekijät, jotka saattoivat lieventää tai vahvistaa fluoridien vaikutusta ympäristöön. Yleisesti fluoridien ympäristö- ja terveysvaikutukset arvioitiin vähäisiksi. Työn kokeellisessa osassa määritettiin Tornion tehtaiden ferrokromitehtaan, terässulaton, kuumavalssaamon ja kylmävalssaamon fluoriditaseet. Jokaisen osastojen syötteiden fluoridipitoisuudet selvitettiin tuottajien ilmoittamien tuotekoostumuksien, spesifikaatioiden ja fluoridianalyysien perusteella. Fluoridien kokonaismäärät laskettiin jokaiselle syötteelle ja ne suhteutettiin kunkin osaston vuoden 2001 tuotantotasoon. Tasetarkastelussa suurimpina fluoridisyötteinä nousivat odotetusti esiin terässulaton käyttämä kuonanmuodostaja-aine fluspaatti (CaF2) ja kylmävalssaamon peittaushappo, 70 prosenttinen fluorivetyhappo (HF). Lisäksi muita merkittäviä syötteitä olivat kylmävalssaamon käyttämä kalkkipitoinen sekakuona ja ferrokromitehtaan sulatuskoksi. Tuotoksien eli päästöjen fluoridipitoisuudet saatiin selville päästömittauksin. Jätevesistä otettiin pääosin viikoittaisia kokoomanäytteitä, jotka analysoitiin tehtaan laboratoriossa. Kaasumaiset tuotokset oli määritetty kertamittauksien perusteella. Kiinteiden tuotoksien eli sakkojen ja kuonien fluoridimittaukset suoritettiin 3 sulatuksen kuonanäytteistä ja sakan vuosinäytteestä. Tuotoksista suurimmat ominaispäästökertoimet olivat juuri terässulaton AOD-konvertterin ja senkkauunin kuonilla ja kylmävalssaamon neutraloidulla regenerointisakalla ja neutralointisakoilla. Näistä ei aiheutunut varsinaista päästöä lähiympäristöön, koska sakat ja kuonat loppusijoitetaan tehtaan kaatopaikalle tai niitä käytetään liukenemattomassa muodossa. Tornion tehtaiden fluoridisyötteiden ja -tuotoksien mittausepätarkkuudet vaikuttivat fluoriditaseeseen. Ferrokromitehtaan fluoridisyötteet olivat kokonaismäärältään selvästi suurempia kuin tuotokset. Terässulaton fluoriditaseen tuotokset olivat suurempia kuin syötteet ja kylmävalssaamon syötteet sekä tuotokset olivat karkeasti arvioiden samaa suuruusluokkaa. Kuumavalssaamon fluoridisyötteet ja -tuotokset olivat mitättömiä. Fluoriditaseen epävarmuustekijöitä voidaan vähentää suorittamalla esimerkiksi useita fluoridimittauksia kaasumaisista päästöistä.

Biogeochemical processes controlling oxygen and carbon isotopes of diatom silica in Late Glacial to Holocene lacustrine rhythmites

Biogeochemical cycles and sedimentary records in lakes are related to climate controls on hydrology and catchment processes. Changes in the isotopic imposition of the diatom frustules (δ 18 O diatom and δ 13 C diatom ) in lacustrine sediments can be used to reconstruct palaeoclimatic and palaeoenvironmental changes. The Lago Chungará (Andean Altiplano, 18°15 ′ S, 69°10 ′ W, 4520 masl) diatomaceous laminated sediments are made up of white and green multiannual rhythmites. White laminae were formed during short-term diatom super-blooms, and are composed almost exclusively of large-sized Cyclostephanos andinus.These diatoms bloom during mixing events when recycled nutrients from the bottom waters are brought to the surface and/or when nutrients are introduced from the catchment during periods of strong runoff. Conversely, the green laminae are thought to have been deposited over several years and are composed of a mixture of diatoms (mainly smaller valves of C. andinus and Discostella stelligera ) and organic matter. These green laminae reflect the lake's hydrological recovery from a status favouring the diatom super-blooms (white laminae) towards baseline conditions. δ 18 O diatom and δ 13 C diatom from 11,990 to 11,530 cal years BP allow us to reconstruct shifts in the precipitation/evaporation ratio and changes in the lake water dissolved carbon concentration, respectively. δ 18 O diatom values indicate that white laminae formation occurred mainly during low lake level stages, whereas green laminae formation generally occurred during high lake level stages. The isotope and chronostratigraphical data together suggest that white laminae deposition is caused by extraordinary environmental events. El Niño-Southern Oscillation and changes in solar activity are the most likely climate forcing mechanisms that could trigger such events, favouring hydrological changes at interannual-to-decadal scale. This study demonstrates the potential for laminated lake sediments to document extreme pluriannual events.

Paperikoneen kuivatusosan haihdutuksen tehostaminen

Tässä diplomityössä käsitellään paperikoneen kuivatusosan haihdutuksen tehostamista. Tutkimuksen aikana toteutettiin pienmittakaavakoe, ja suunniteltiin tuotantokonekoe. Molemmat kokeet perustuvat tutkimuksen aikana johdettuun teoriaan ja niiden tarkoituksena on kerätä lisää tietoa haihdutuksesta. Pienmittakaavakokeessa löydettiin uusi tapa tehostaa haihdutusta. Kokeen perusteella ei kuitenkaan voida varmuudella arvioida tavan hyötyjä ja soveltuvuutta tuotantokoneelle. Suositeltavaa onkin jatkossa toteuttaa työssä esitetty tuotantokonekoe, jotta auki jäävät kysymykset saavat vastauksensa ja saadaan selkeä käsitys uuden tavan hyödynnettävyydestä paperikoneen kuivatusosalla.

Measurement Problems and Problem-Solving in Kraft Pulping

Tämän työn tarkoituksena on koota yhteen selluprosessin mittausongelmat ja mahdolliset mittaustekniikat ongelmien ratkaisemiseksi. Pääpaino on online-mittaustekniikoissa. Työ koostuu kolmesta osasta. Ensimmäinen osa on kirjallisuustyö, jossa esitellään nykyaikaisen selluprosessin perusmittaukset ja säätötarpeet. Mukana on koko kuitulinja puunkäsittelystä valkaisuun ja kemikaalikierto: haihduttamo, soodakattila, kaustistamo ja meesauuni. Toisessa osassa mittausongelmat ja mahdolliset mittaustekniikat on koottu yhteen ”tiekartaksi”. Tiedot on koottu vierailemalla kolmella suomalaisella sellutehtaalla ja haastattelemalla laitetekniikka- ja mittaustekniikka-asiantuntijoita. Prosessikemian paremmalle ymmärtämiselle näyttää haastattelun perusteella olevan tarvetta, minkä vuoksi konsentraatiomittaukset on valittu jatkotutkimuskohteeksi. Viimeisessä osassa esitellään mahdollisia mittaustekniikoita konsentraatiomittausten ratkaisemiseksi. Valitut tekniikat ovat lähi-infrapunatekniikka (NIR), fourier-muunnosinfrapunatekniikka (FTIR), online-kapillaarielektroforeesi (CE) ja laserindusoitu plasmaemissiospektroskopia (LIPS). Kaikkia tekniikoita voi käyttää online-kytkettyinä prosessikehitystyökaluina. Kehityskustannukset on arvioitu säätöön kytketylle online-laitteelle. Kehityskustannukset vaihtelevat nollasta miestyövuodesta FTIR-tekniikalle viiteen miestyövuoteen CE-laitteelle; kehityskustannukset riippuvat tekniikan kehitysasteesta ja valmiusasteesta tietyn ongelman ratkaisuun. Työn viimeisessä osassa arvioidaan myös yhden mittausongelman – pesuhäviömittauksen – ratkaisemisen teknis-taloudellista kannattavuutta. Ligniinipitoisuus kuvaisi nykyisiä mittauksia paremmin todellista pesuhäviötä. Nykyään mitataan joko natrium- tai COD-pesuhäviötä. Ligniinipitoisuutta voidaan mitata UV-absorptiotekniikalla. Myös CE-laitetta voitaisiin käyttää pesuhäviön mittauksessa ainakin prosessikehitysvaiheessa. Taloudellinen tarkastelu pohjautuu moniin yksinkertaistuksiin ja se ei sovellu suoraan investointipäätösten tueksi. Parempi mittaus- ja säätöjärjestelmä voisi vakauttaa pesemön ajoa. Investointi ajoa vakauttavaan järjestelmään on kannattavaa, jos todellinen ajotilanne on tarpeeksi kaukana kustannusminimistä tai jos pesurin ajo heilahtelee eli pesuhäviön keskihajonta on suuri. 50 000 € maksavalle mittaus- ja säätöjärjestelmälle saadaan alle 0,5 vuoden takaisinmaksuaika epävakaassa ajossa, jos COD-pesuhäviön vaihteluväli on 5,2 – 11,6 kg/odt asetusarvon ollessa 8,4 kg/odt. Laimennuskerroin vaihtelee tällöin välillä 1,7 – 3,6 m3/odt asetusarvon ollessa 2,5 m3/odt.

Effect of radar rainfall time resolution on the predictive capability of a distributed hydrologic model

The performance of a hydrologic model depends on the rainfall input data, both spatially and temporally. As the spatial distribution of rainfall exerts a great influence on both runoff volumes and peak flows, the use of a distributed hydrologic model can improve the results in the case of convective rainfall in a basin where the storm area is smaller than the basin area. The aim of this study was to perform a sensitivity analysis of the rainfall time resolution on the results of a distributed hydrologic model in a flash-flood prone basin. Within such a catchment, floods are produced by heavy rainfall events with a large convective component. A second objective of the current paper is the proposal of a methodology that improves the radar rainfall estimation at a higher spatial and temporal resolution. Composite radar data from a network of three C-band radars with 6-min temporal and 2 × 2 km2 spatial resolution were used to feed the RIBS distributed hydrological model. A modification of the Window Probability Matching Method (gauge-adjustment method) was applied to four cases of heavy rainfall to improve the observed rainfall sub-estimation by computing new Z/R relationships for both convective and stratiform reflectivities. An advection correction technique based on the cross-correlation between two consecutive images was introduced to obtain several time resolutions from 1 min to 30 min. The RIBS hydrologic model was calibrated using a probabilistic approach based on a multiobjective methodology for each time resolution. A sensitivity analysis of rainfall time resolution was conducted to find the resolution that best represents the hydrological basin behaviour.

The snow storm of the 8th of March 2010 in Barcelona: a paradigmatic case

A heavy precipitation event swept over Catalonia (NE Spain) on 8 March 2010, with a total amount that ex- ceeded 100mm locally and snowfall of more than 60cm near the coast. Unusual for this region and at this time of the year, this snowfall event affected mainly the coastal region and was accompanied by thunderstorms and strong wind gusts in some areas. Most of the damage was due to"wet snow", a kind of snow that favours accretion on power lines and causes line-breaking and subsequent interruption of the electricity supply. This paper conducts an interdisciplinary analysis of the event to show its great societal impact and the role played by the recently developed social networks (it has been called the first"Snowfall 2.0"), as well to analyse the meteorologi- cal factors associated with the major damage, and to propose an indicator that could summarise them. With this aim, the paper introduces the event and its societal impact and com- pares it with other important snowfalls that have affected the Catalan coast, using the PRESSGAMA database. The sec- ond part of the paper shows the event"s main meteorological features and analyses the near-surface atmospheric variables responsible for the major damage through the application of the SAFRAN (Système d"analyse fournissant des renseigne- ments atmosphériques à la neige) mesoscale analysis, which, together with the proposed"wind, wet-snow index" (WWSI), allows to estimate the severity of the event. This snow storm provides further evidence of our vulnerability to natural haz- ards and highlights the importance of a multidisciplinary ap- proach in analysing societal impact and the meteorological factors responsible for this kind of event.

Mesoscale numerical analysis of the historical November 1982 heavy precipitation event over Andorra (Eastern Pyrenees)

From 6 to 8 November 1982 one of the most catastrophic flash-flood events was recorded in the Eastern Pyrenees affecting Andorra and also France and Spain with rainfall accumulations exceeding 400 mm in 24 h, 44 fatalities and widespread damage. This paper aims to exhaustively document this heavy precipitation event and examines mesoscale simulations performed by the French Meso-NH non-hydrostatic atmospheric model. Large-scale simulations show the slow-evolving synoptic environment favourable for the development of a deep Atlantic cyclone which induced a strong southerly flow over the Eastern Pyrenees. From the evolution of the synoptic pattern four distinct phases have been identified during the event. The mesoscale analysis presents the second and the third phase as the most intense in terms of rainfall accumulations and highlights the interaction of the moist and conditionally unstable flows with the mountains. The presence of a SW low level jet (30 m s-1) around 1500 m also had a crucial role on focusing the precipitation over the exposed south slopes of the Eastern Pyrenees. Backward trajectories based on Eulerian on-line passive tracers indicate that the orographic uplift was the main forcing mechanism which triggered and maintained the precipitating systems more than 30 h over the Pyrenees. The moisture of the feeding flow mainly came from the Atlantic Ocean (7-9 g kg-1) and the role of the Mediterranean as a local moisture source was very limited (2-3 g kg-1) due to the high initial water vapour content of the parcels and the rapid passage over the basin along the Spanish Mediterranean coast (less than 12 h).

A look to the HyMeX program (Una mirada al programa HyMeX)

The international HyMeX (Hydrological Mediterranean Experiment) program aims to improve our understanding of the water cycle in the Mediterranean, using a multidisciplinary and multiscale approach and with emphasis on extreme events. This program will improve our understanding and our predictive ability of hydrometeorological hazards including their evolution within the next century. One of the most important results of the program will be its observational campaigns, which will greatly improve the data available, leading to significant scientific results. The interest of the program for the Spanish research groups is described, as the active participation of some of them in the design and execution of the observational activities. At the same time, due to its location, Spain is key to the program, being a good observation platform. HyMeX will enrich the work of the Spanish research groups, it will improve the predictive ability of the weather services, will help us to have a better understanding of the impacts of hydrometeorological extremes on our society and will lead to better strategies for adapting to climate change.

Activity of daptomycin- and vancomycin-loaded poly-epsilon-caprolactone microparticles against mature staphylococcal biofilms.

The aim of the present study was to develop novel daptomycin-loaded poly-epsilon-caprolactone (PCL) microparticles with enhanced antibiofilm activity against mature biofilms of clinically relevant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and polysaccharide intercellular adhesin-positive Staphylococcus epidermidis. Daptomycin was encapsulated into PCL microparticles by a double emulsion-solvent evaporation method. For comparison purposes, formulations containing vancomycin were also prepared. Particle morphology, size distribution, encapsulation efficiency, surface charge, thermal behavior, and in vitro release were assessed. All formulations exhibited a spherical morphology, micrometer size, and negative surface charge. From a very early time stage, the released concentrations of daptomycin and vancomycin were higher than the minimal inhibitory concentration and continued so up to 72 hours. Daptomycin presented a sustained release profile with increasing concentrations of the drug being released up to 72 hours, whereas the release of vancomycin stabilized at 24 hours. The antibacterial activity of the microparticles was assessed by isothermal microcalorimetry against planktonic and sessile MRSA and S. epidermidis. Regarding planktonic bacteria, daptomycin-loaded PCL microparticles presented the highest antibacterial activity against both strains. Isothermal microcalorimetry also revealed that lower concentrations of daptomycin-loaded microparticles were required to completely inhibit the recovery of mature MRSA and S. epidermidis biofilms. Further characterization of the effect of daptomycin-loaded PCL microparticles on mature biofilms was performed by fluorescence in situ hybridization. Fluorescence in situ hybridization showed an important reduction in MRSA biofilm, whereas S. epidermidis biofilms, although inhibited, were not eradicated. In addition, an important attachment of the microparticles to MRSA and S. epidermidis biofilms was observed. Finally, all formulations proved to be biocompatible with both ISO compliant L929 fibroblasts and human MG63 osteoblast-like cells.

Simultaneous determination of gross alpha, gross beta and Ra-226 in natural water by liquid scintillation counting.

The determination of gross alpha, gross beta and 226Ra activity in natural waters is useful in a wide range of environmental studies. Furthermore, gross alpha and gross beta parameters are included in international legislation on the quality of drinking water [Council Directive 98/83/EC].1 In this work, a low-background liquid scintillation counter (Wallac, Quantulus 1220) was used to simultaneously determine gross alpha, gross beta and 226Ra activity in natural water samples. Sample preparation involved evaporation to remove 222Rn and its short-lived decay daughters. The evaporation process concentrated the sample ten-fold. Afterwards, a sample aliquot of 8 mL was mixed with 12 mL of Ultima Gold AB scintillation cocktail in low-diffusion vials. In this study, a theoretical mathematical model based on secular equilibrium conditions between 226Ra and its short-lived decay daughters is presented. The proposed model makes it possible to determine 226Ra activity from two measurements. These measurements also allow determining gross alpha and gross beta simultaneously. To validate the proposed model, spiked samples with different activity levels for each parameter were analysed. Additionally, to evaluate the model's applicability in natural water, eight natural water samples from different parts of Spain were analysed. The eight natural water samples were also characterised by alpha spectrometry for the naturally occurring isotopes of uranium (234U, 235U and 238U), radium (224Ra and 226Ra), 210Po and 232Th. The results for gross alpha and 226Ra activity were compared with alpha spectrometry characterization, and an acceptable concordance was obtained.

Refráns meteorolóxicos e atlas románicos, paremioloxía e territorio

Tras unha presentación da Base de datos sobre refranes del calendario y meteorológicos en la Romania (BADARE) e do progresivo baleirado nela de diversos atlas lingüísticos da Romania, preséntanse tres mostras da variación diatópica deste tipo de refráns no espazo iberorromance: (1) coa implicación do arco da vella, (2) dos roibéns e (3) das imaxes de ceo ovellado e afíns. Cómpre destacar o grande interese dos materiais contidos nos atlas románicos, que se poden complementar cos doutras obras vinculadas á lingua e ao territorio: repertorios paremiográficos, monografías dialectais, achegas diversas. Aínda que non parece factible un grande atlas paremiolóxico romance nin sequera de segunda xeración, pois os refráns (meteorolóxicos o de outros tipos) son nos atlas de primeira xeración unha propina ocasional, coidamos que mediante a base de datos BADARE se poden administrar eses materiais de xeito que faciliten o estudo da paremioloxía románica ligada ao territorio.

Inférence de source de traces d'essence retrouvées dans des débris d'incendie: Evaluation de la contribution de la chromatographie en phase gazeuse couplée à la spectrométrie de masse à rapport isotopique

Lorsque de l'essence est employée pour allumer et/ou propager un incendie, l'inférence de la source de l'essence peut permettre d'établir un lien entre le sinistre et une source potentielle. Cette inférence de la source constitue une alternative intéressante pour fournir des éléments de preuve dans ce type d'événements où les preuves matérielles laissées par l'auteur sont rares. Le but principal de cette recherche était le développement d'une méthode d'analyse de spécimens d'essence par GC-IRMS, méthode pas routinière et peu étudiée en science forensique, puis l'évaluation de son potentiel à inférer la source de traces d'essence en comparaison aux performances de la GC-MS. Un appareillage permettant d'analyser simultanément les échantillons par MS et par IRMS a été utilisé dans cette recherche. Une méthode d'analyse a été développée, optimisée et validée pour cet appareillage. Par la suite, des prélèvements d'essence provenant d'un échantillonnage conséquent et représentatif du marché de la région lausannoise ont été analysés. Finalement, les données obtenues ont été traitées et interprétées à l'aide de méthodes chimiométriques. Les analyses effectuées ont permis de montrer que la méthodologie mise en place, aussi bien pour la composante MS que pour l'IRMS, permet de différencier des échantillons d'essence non altérée provenant de différentes stations-service. Il a également pu être démontré qu'à chaque nouveau remplissage des cuves d'une station-service, la composition de l'essence distribuée par cette station est quasi unique. La GC-MS permet une meilleure différenciation d'échantillons prélevés dans différentes stations, alors que la GC-IRMS est plus performante lorsqu'il s'agit de comparer des échantillons collectés après chacun des remplissages d'une cuve. Ainsi, ces résultats indiquent que les deux composantes de la méthode peuvent être complémentaires pour l'analyse d'échantillons d'essence non altérée. Les résultats obtenus ont également permis de montrer que l'évaporation des échantillons d'essence ne compromet pas la possibilité de grouper des échantillons de même source par GC-MS. Il est toutefois nécessaire d'effectuer une sélection des variables afin d'éliminer celles qui sont influencées par le phénomène d'évaporation. Par contre, les analyses effectuées ont montré que l'évaporation des échantillons d'essence a une forte influence sur la composition isotopique des échantillons. Cette influence est telle qu'il n'est pas possible, même en effectuant une sélection des variables, de grouper correctement des échantillons évaporés par GC-IRMS. Par conséquent, seule la composante MS de la méthodologie mise en place permet d'inférer la source d'échantillons d'essence évaporée. _________________________________________________________________________________________________ When gasoline is used to start and / or propagate an arson, source inference of gasoline can allow to establish a link between the fire and a potential source. This source inference is an interesting alternative to provide evidence in this type of events where physical evidence left by the author are rare. The main purpose of this research was to develop a GC-IRMS method for the analysis of gasoline samples, a non-routine method and little investigated in forensic science, and to evaluate its potential to infer the source of gasoline traces compared to the GC-MS performances. An instrument allowing to analyze simultaneously samples by MS and IRMS was used in this research. An analytical method was developed, optimized and validated for this instrument. Thereafter, gasoline samples from a large sampling and representative of the Lausanne area market were analyzed. Finally, the obtained data were processed and interpreted using chemometric methods. The analyses have shown that the methodology, both for MS and for IRMS, allow to differentiate unweathered gasoline samples from different service stations. It has also been demonstrated that each new filling of the tanks of a station generates an almost unique composition of gasoline. GC-MS achieves a better differentiation of samples coming from different stations, while GC-IRMS is more efficient to distinguish samples collected after each filling of a tank. Thus, these results indicate that the two components of the method can be complementary to the analysis of unweathered gasoline samples. The results have also shown that the evaporation of gasoline samples does not compromise the possibility to group samples coming from the same source by GC-MS. It is however necessary to make a selection of variables in order to eliminate those which are influenced by the evaporation. On the other hand, the carried out analyses have shown that the evaporation of gasoline samples has such a strong influence on the isotopic composition of the samples that it is not possible, even by performing a selection of variables, to properly group evaporated samples by GC-IRMS. Therefore, only the MS allows to infer the source of evaporated gasoline samples.