In this thesis, partial discharge (PD) phenomenon in oil-impregnated paper (OIP) is investigated under accelerated electrical stress. The thesis is mainly focused on the characteristic of PD activity and the influence it has on the insulation properties of OIP. PD source was created by introducing an air filled cavity embedded between layers of OIP. PD activity is investigated from the initiation up to final puncture breakdown of the OIP. The time-evolution of number, maximum magnitude and average magnitude of PD is investigated for cavities with different diameter and height. It was found that time to breakdown is shorter if the cavity diameter is larger and cavities with higher depth produce larger PDs. Comparison between PD activity in three cases, i.e. unaged OIP, thermally aged OIP and OIP samples with higher moisture content is performed. In general, it is found that for all cases the number and the maximum magnitude of PD follows a similar trend versus ageing time. During the very beginning of the experiment large discharges occur and they disappear after a short ageing time. Number and maximum magnitude of PD increase with time until reaching a peak value. Finally both parameters decrease with time and puncture breakdown occurs in the sample. Even though PD activity in thermally aged OIP is higher compared to the unaged OIP samples, the time to breakdown for new and thermally aged OIP samples is similar while it is shorter for OIP samples with higher moisture content. In this thesis, partial discharge (PD) phenomenon in oil-impregnated paper (OIP) is investigated under accelerated electrical stress. The thesis is mainly focused on the characteristic of PD activity and the influence it has on the insulation properties of OIP. PD source was created by introducing an air filled cavity embedded between layers of OIP. PD activity is investigated from the initiation up to final puncture breakdown of the OIP. The time-evolution of number, maximum magnitude and average magnitude of PD is investigated for cavities with different diameter and height. It was found that time to breakdown is shorter if the cavity diameter is larger and cavities with higher depth produce larger PDs. Comparison between PD activity in three cases, i.e. unaged OIP, thermally aged OIP and OIP samples with higher moisture content is performed. In general, it is found that for all cases the number and the maximum magnitude of PD follows a similar trend versus ageing time. During the very beginning of the experiment large discharges occur and they disappear after a short ageing time. Number and maximum magnitude of PD increase with time until reaching a peak value. Finally both parameters decrease with time and puncture breakdown occurs in the sample. Even though PD activity in thermally aged OIP is higher compared to the unaged OIP samples, the time to breakdown for new and thermally aged OIP samples is similar while it is shorter for OIP samples with higher moisture content. Breakdown strength of OIP samples is measured before and after ageing with PDs. It is found that the breakdown strength of OIP samples decreases by around 40% after the sample is exposed to accelerated electrical ageing. Furthermore a thermal model was developed to investigate the possible transition of breakdown mechanism from erosion to thermal breakdown in OIP dielectrics. It was found that PD activity can lower the thermal breakdown voltage of OIP up to four times. / <p>QC 20150206</p>

Introduktion: Befuktning vid mekanisk ventilation är nödvändigt för att inte skador skall uppstå i luftvägarna. Luften kan befuktas aktivt eller passivt och då tekniken ständigt utvecklas kan tidigare riktlinjer för vilken metod som är bäst behöva revideras. Syfte: Studiens syfte var att undersöka evidensen för användning av aktiv befuktning hos intuberade eller trakeostomerade patienter. Metod: I enlighet med Whittemore &amp; Knafls metod utfördes en integrerad litteraturstudie. Litteratursökning gjordes i databaserna PubMed, CINAHL och Cochrane. Även en manuell sökning i referenslistor utfördes och ledde till att totalt 14 artiklar valdes ut, varav 13 var kvantitativa och 1 kvalitativ. Resultat: Analysen av de 14 artiklarna resulterade i fyra huvudkategorier med efterföljande underrubriker: Aktiv befuktnings påverkan på nosokomiala infektioner: Infektionsincidens och Infektionstyp; Aktiv befuktnings påverkan på luftvägsproblem: Ocklusionsproblemoch Sekretviskositet/sekretmängd; Aktiv befuktnings påverkan på mekanisk ventilation: Vårdtid med mekanisk ventilation och Påverkan på andningsarbete;Upplevelse av aktiv befuktning: Upplevd påverkan på hälsa och Negativ påverkanpå vårdmiljön. Konklusion: Denna studie var att aktiv befuktning har en viktigfunktion att fylla hos vissa patienter, men borde inte användas slentrianmässigt.Sjuksköterskan har en viktig roll i att hitta de patienter som är mest hjälpta av det. / Introduction: Humidification during mechanical ventilation is necessary to avoid damage in the airways. The air can be humidified actively or passively and since thetechnique is constant developing the guidelines for which of the alternative that’sthe best may need to be revised. Aim: The aim of the study was to examine the evidence of using active humidification in intubated patients or in patients withtracheostomy. Method: An integrated literature review according to Whittemore &amp;Knafl was carried through. The literature search was done in the databases PubMed, CINAHL and Cochrane. A manual search in reference lists was also made and resulted in a total of 14 articles whereof 13 were quantitative and one was qualitative. Result: The analysis of the 14 articles led to four main categories with the following subcategories: Active humidifications influence on nosocomial infections: Infectionincidence and Infection type; Active humidifications influence on airway problems: Occlusion problems and Mucus viscosity/mucus volume; Active humidifications influence on mechanical ventilation: Time on mechanical ventilation and Influenceon respiratory work; Experience of active humidification: Experienced influence on health and Negative impact on hospital environment. Conclusion: The conclusion of this study was that active humidification is the better choice among certain patientgroups but should not be used routinely. The nurse plays an important role in finding the patients who can benefit the most of it.

Vast amounts of carbon are stored forest soils, a product of decaying organic matter. Increased CO2 in the atmosphere is predicted to lead to increasing global temperatures, and more extreme moisture regimes. Such increases in mean temperature could accelerate the rate of organic matter decay in soils and lead to additional release of CO2 into the atmosphere, thus exacerbating climate change. However, due to its impact on plant metabolism, high atmospheric CO2 concentrations may also lead to greater condensed tannins (CT) and reduced nitrogen (N) content in leaf litter. This reduction in litter quality has the potential to slow decay of organic matter in soil and therefore offset the accelerated decay resulting from a warmer climate. My research aimed to quantify the effects of climate and litter chemistry, specifically CT and N, on litter decay, N mineralization and associated microbes in the field. Strings of litterbags were laid on the forest floor along climate transects of mature Douglas-fir stands of coastal British Columbia rain-shadow forests. In-situ climate was monitored alongside carbon and nitrogen loss over 3.58 years of decay along three transects located at different latitudes, each transect spanning the coastal Western Hemlock and Douglas-fir biogeoclimatic zones. Microbial communities in the decaying litter and in forest soils were also analyzed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Microbial biogeography at field sites was partially influenced by climate, soil characteristics and spatial distance, but did not improve best fit decay models using climate and litter chemistry variables. Litter with greater initial CT and smaller N concentration slowed down early decay (0 - 0.58 yr) and net N mineralization. Warmer temperatures accelerated later decay (0.58 - 3.58 yr) and net N mineralization. Water-soluble CT were rapidly lost during decay, while other forms of CT were likely responsible for slower decay. The composition of fungal communities on decaying litter was affected by initial concentrations of CT and N. On a yearly basis, the slower decay of litter with high CT and reduced N content can offset accelerated rates of decay associated with warmer temperatures. Concurrent shifts in microbial communities and net N mineralization suggest potential benefits to trees. / Graduate / 2017-12-19

Wood products play a key role in the transformation to a more sustainable society based on renewable bio-based resources, together with the positive effects on climate mitigation by replacing fossil fuels. However, to increase the use of forest fuel in practice it is important to understand the effects of handling and storage on its quality and removal of nutrients from the forest. This thesis addresses these effects with special focus on a comparative evaluation of the traditional dried-stacked with “new” and to some extent more controversial fresh-stacked methods for extraction of logging residues from Norway spruce (Picea abies (L.) Karst). The results indicate that a normal extraction of logging residues will leave at least 20% of logging residues at the clear-felled area, in accordance with Swedish Forest Agency recommendations. However, the results also indicate that the ambition of the dried-stacked method to leave the majority of the needles well spread over the clear-felled area does not meet these recommendations. In fact, the harvesting operation is more important than the extraction method, with respect to how much logging residues (nutrients) being left in the forest. The results also show that the quality of fuel yielded by the two handling methods differs only to minor extent, indicating that other factors have stronger effects, where “dried-stacked” and “fresh-stacked” logging residues from different clear-felling areas is often similar. Generally, logging residues stored over summer (regardless method), seem to provide sufficiently dry forest fuel, with a needle content of about 5–10%. There is a clear correlation between drying and effective loss of needles from twigs, but the loss does not necessarily mean that the needles will remain in the forest.  However, needle color (green or brown) is not a strong indicator for a reduction in needle content. Acceptance of the fresh-stacked method would provide opportunities for the development of new technologies, more efficient use of machinery throughout the whole year, reduced costs, shorter lead times and increased amounts of logging residues extracted from each clear-felled area. This is mainly because it would enable extraction at optimal times from a logistical, financial and/or forestry perspectives. Written in English with summary and conclusion in Swedish. / Skogen och dess produkter har en nyckelroll i omställningen till ett framtida hållbart samhälle eftersom användande av träråvara har en positiv effekt på klimatet, t.ex. genom träbyggande eller att fossila bränslen ersätts med bioenergi. Men för att kunna ta tillvara mer skogsbränsle i form av grenar och toppar (grot) från bestånd dominerade av gran (Picea abies (L.) Karst) är det viktigt att förstå hur hanteringen påverkar såväl bränslekvalitet som bortförsel av näringsämnen från skogen. Denna avhandling belyser hanteringens effekter på bränslekvalitet och näringsförluster genom att jämföra den traditionella metoden (skotning av torkad grot, ”brunrisskotning”), med den ”nya” och till viss del ifrågasatta skotningen av färsk grot (”grönrisskotning”). Resultatet visar att ett normalt grot-uttag kommer att lämna minst 20 % av groten kvar på hygget, helt i linje med Skogsstyrelsens rekommendationer. Däremot uppfylls inte rekommendationerna med avseende på att lämna merparten av barren väl spridda på hygget, detta trots att det är ambitionen med den traditionella hyggestorkningen av grot. Hur mycket grot (och således näringsämne) som lämnas kvar på hygget påverkas i själva verket mer av hur avverkningen utförs, än när groten skotas ihop. Resultatet visar också en skillnad i bränslekvalitet mellan de båda beskrivna hanteringsmetoderna. Denna skillnad är dock så liten att andra faktorer sannolikt påverkar mer än hanteringsmetoden. Hyggestorkad grot från ett enskilt hygge i södra Sverige, kan i verkligheten ofta vara ganska likt färskskotad grot från ett annat hygge. Grot som har lagrats över sommaren kan alltså förväntas ha torkat tillräckligt, samt ha en barrandel på ca 5–10 % oavsett hanteringsmetod. Det verkar också finnas ett klart samband mellan torkning och att barren släpper från kvisten, men det betyder inte nödvändigtvis att barren blir kvar i skogen. Hur som helst, barrens färg (gröna eller bruna) är inte en rättvisande indikator på avbarrning. Om skotning av färsk grot accepteras ger det möjligheter för utveckling av ny teknik, effektivare användning av maskinresurser över hela året, minskade kostnader, kortare ledtider, samt möjligt ökat grot-uttag från enskilda hyggen. Detta beror främst på att det skulle vara möjligt att utföra grot-uttaget när det passar bäst ur ett logistiskt, ekonomiskt och/eller skogligt perspektiv. Skriven på engelska, men med sammanfattning och slutsatser på svenska / <p><strong>Tidigare handledare har också varit:</strong></p><p>Thomas Thörnqvist, Professor, Linnéuniversitetet</p><p>Dick Dandberg, Professor, Linnéuniversitetet</p><p>Åsa Blom, Docent, Linnéuniversitetet</p><p><strong>Sammanläggningsavhandlingen består av totalt fyra Paper:</strong></p><p>Paper I</p><p>Nilsson, B., Blom, Å., Thörnqvist, T. 2013. The influence of two different handling methods on the moisture content and composition of logging residues. <em>Biomass and Bioenergy</em>, 52, 34–42.</p><p>Paper II</p><p>Nilsson, B., Nilsson, D., Thörnqvist, T. 2015. Distributions and losses of logging residues at clear-felled areas during extraction for bioenergy: Comparing dried- and fresh-stacked method. <em>Forests</em>, 6, 4212–4227.</p><p>Paper III</p><p>Nilsson, D., Nilsson, B., Thörnqvist, T., Bergh, J. 2016. Amount of nutrients extracted and left behind at the clear-felled area using the fresh- and dried-stacked method of logging residue extraction. Submitted to <em>Scandinavian Journal of Forest Research </em>(2016-11-01).</p><p>Paper IV</p><p>Nilsson, B., Lerman, P. 2016. Experimental study of relations between defoliation, moisture content and color change in logging residues. Department of Forestry and Wood Technology, Linnaeus University, Växjö, Sweden. <em>Manuscript</em>.</p>

Ce mémoire visait à déterminer les pratiques et les facteurs favorables au succès des réintroductions du carex faux-lupulina (Carex lupuliformis), une espèce vivace menacée poussant dans divers types de milieux humides ouverts du nord-est de l’Amérique du Nord. Pour répondre à cet objectif, des expériences de germination en serres ont été réalisées, et la survie, la vigueur et le microhabitat de chaque plant de carex faux-lupulina connu au Québec (sauvage ou réintroduit) ont été mesurés. Nos résultats montrent que le carex faux-lupulina est une espèce facile à propager ex situ. Une stratification froide (4°C) des semences dans du sable humide pendant un mois induit des taux de germination élevés. Nos résultats montrent également que des pucerons exotiques, ainsi qu’une transplantation dans des habitats inadaptés aux besoins de l’espèce en termes d’humidité du sol et de lumière disponible, ont causé la mort prématurée d’un grand nombre de transplants. Notre programme de réintroduction a permis d’établir une nouvelle population de l’espèce au Québec, et a potentiellement permis de sextupler la taille des populations de la province. Globalement, cette étude a permis de mieux comprendre l’écologie du carex faux-lupulina, et ainsi de faciliter la restauration de ses populations. / This study aimed to determine the practices and factors influencing the success of the reintroductions of false hop sedge, an endangered perennial species growing in North American open wetlands. To do so, germination experiments were performed, and the survival, vigour and microhabitat of each false hop sedge plant known in Québec (wild or reintroduced) were measured. Our results show that false hop sedge is easy to propagate ex situ. A cold stratification (4°C) of seeds in wet sand for one month induced higher germination rates. Our results also show that exotic aphids, as well as a transplantation in habitats that did not meet the false hop sedge requirements in terms of soil moisture and available light, caused the premature death of many transplants. Our reintroduction program allowed the establishment of at least one new false hop sedge population in Québec, and potentially contributed to sextupling the size of the provincial population. Overall, this study allowed us to better understand the ecology of false hop sedge, and thus facilitate the restoration of its populations.

Le plâtre est un matériau de grande disponibilité et très connu pour ses qualités : il est favorable à la protection de l’environnement, assez malléable, de faible densité, aux propriétés fonctionnelles remarquables (coupe-feu, isolant thermique, régulateur de l’hygrométrie des enceintes), décoratif, ... Ce qui justifie l’intérêt accordé à ce matériau pour les constructions. Sa grande fragilité préoccupante est à l’origine des travaux de recherches dans le monde entier en vue de son renforcement. Les fibres de verre et de sisal sont les renforts les plus utilisés à ce jour. Le renforcement par des fibres végétales est de plus en plus recherché. La texture micro structurale poreuse du plâtre favorise son caractère d’isolant thermique. Les textures mises en œuvre jusqu’à présent sont limitées à des porosités comprises entre 30 et 55%. La réduction du coût de ce matériau pour une large utilisation est encore possible et souhaitée. Deux leviers sont exploités dans ce travail, notamment un allègement de la masse de plâtre pour augmenter le taux de porosité et un renforcement de la tenue mécanique par incorporation de fibres végétales produites localement. L’objectif de ce travail est d’évaluer les caractéristiques mécaniques, thermiques et hygrométriques d’un matériau constitué de plâtre pris, à grande porosité, renforcé d’une nouvelle fibre végétale : le Rhecktophyllum Camerunense (RC), une fibre des forêts humides équatoriales. La fibre de sisal, d’utilisation connue pour le renforcement du plâtre, sert de référence à des fins de comparaison. Une série d’expérimentations est menée à cet effet. Une caractérisation physico-chimique des constituants est effectuée, des essais mécaniques de traction et de flexion sont effectués sur les constituants et les matériaux composites plâtre/fibres résultants, la cinétique d’adsorption d’humidité par les constituants et le matériau fibreux est suivie. Le comportement thermique des matériaux plâtre et plâtre/fibres est aussi mesuré. Les fibres utilisées, le sisal et le RC, sont à fort taux de cellulose (entre 49 et 78,8%), la fibre de RC est tubulaire avec 35,5% de porosité. Le plâtre est gâché à l’eau déminéralisée à un rapport massique E/P égal à 1 à partir de la poudre de semihydrate β. Sa microstructure cristalline est constituée de cristaux de gypse sous forme d’aiguilles enchevêtrées avec des vides intercristallins. Sur le plan du comportement mécanique, les résultats obtenus révèlent que le plâtre se montre fragile et présente un module d’élasticité en traction de 1,72 GPa, une résistance à la traction de 0,86 MPa et un allongement à la rupture de 1,16%. En flexion trois points, son module d’élasticité est de 0,64 GPa et sa contrainte à la rupture, de 0,13 MPa. La fibre de sisal est raide et fragile. Son module d’élasticité est compris entre 9 et 21 GPa, elle admet un allongement à rupture de 3 à 7%. Par contre, la fibre de RC est assez ductile avec un module d’Young moyen de 0,7 GPa et un allongement à rupture de 24,2%. L’adhésion du plâtre sur les fibres est faible : il adhère plus sur le sisal que sur le RC. Le sisal renforce mieux le plâtre par une augmentation plus sensible du module d’élasticité de 42,5%, contre 16,3% pour le RC, ce dernier lui apportant plutôt une grande ductilité élastique. Les fibres de RC apportent le maximum de renforcement en traction au plâtre lorsqu’elles sont tissées en unidirectionnel et en flexion lorsqu’elles sont uniformément réparties dans le volume suivant la direction longitudinale de la structure. (...) / The plaster is a material of high availability and very known for its qualities : it is favourable to the protection of the environment, quite malleable, of low density, its functional properties are remarkable (firewall, thermal insulation, regulator of the hygroscopy of enclosures), decorative, ... What justifies the interest attached to this material for constructions. Its great alarming brittleness is at the origin of the research tasks in the whole world for its strengthening. The glass fibers and sisal are the more used reinforcements to this day. The strengthening by plant fibers is more and more researched. The microstructure of the plaster is porous ; that promotes its heat insulation character. The textures implemented so far are limited to porosities ranging between 30 and 55%. The reduction of cost of this material for a wide use is still possible and desired. Two levers are exploited in this work, in particular a lightening of the plaster weight to increase the proportion of air voids and a reinforcement of the mechanical resistance with locally produced fibers. The objective of this work is to evaluate the mechanical, thermal and hygrometrical characteristics of a material made up of harden plaster, with high porosity, strengthened by a new plant fiber : the Rhecktophyllum Camerunense (RC), a fiber of humid equatorial forests. The sisal fiber, of known use for the strengthening of the plaster, serves as a reference for comparison purposes. A serie of experiments is conducted to this effect. A physicochemical characterization of constituents is performed. Mechanical tests of tensile and of bending are performed on the constituents and the resulting plaster/fiber composite materials. The kinetic adsorption of moisture by the constituents is followed. The thermal behaviour of plaster and plaster/fiber is also measured. The fibers used, sisal and RC are with high rates of cellulose (between 49 and 78.8% ), the fiber of RC is tubular with 35.5 % of porosity. The plaster is dissolved in demineralized water to a mass ratio W/P equals to 1 from the powder of semihydrate β. Its crystalline microstructure is composed of gypsum crystals in the form of needles tangled with the empty intercristallins. As far as the mechanical behavior is concerne, the result reveals that the plaster is weak, its Young’s modulus in tensile is 1.72 GPa, its tensile strength is 0.86 MPa and its elongation at break is 1.16 %. In three points bending test, its modulus of elasticity is 0.64 GPa and its constraint at break is 0.13 MPa. The sisal fiber is stiff and fragile. Its Young’s modulus is between 9 and 21 GPa, it admits an elongation at break of 3 to 7 %. On the other side, the fiber of RC is quite ductile : the means of Young’s module is 7 GPa and the elongation at break is 24.2 %. The adhesion of the plaster on the fiber surface is low : it adheres more on the sisal than on the RC. The sisal strengthened better the plaster with a sensitive increase of the Young’s modulus of 42.5 %, against 16.3 % for the RC. But the RC fiber gives rather high elastic ductility. The fibers of RC deliver maximum capacity in tensile to the plaster when they are woven into unidirectional. They offer high capacity in bending when they are uniformly distributed inside the volume according to the longitudinal direction of the structure. (...)

Le climat du bassin méditerranéen est caractérise par un fort impact du déficit hydrique sur la croissance de la végétation. Dans ces régions fréquemment affectées par les sècheresses, l'humidité des sols est un facteur essentiel des processus hydrologiques et de la croissance de la végétation. Des études climatiques récentes ont montré qu'il est probable que le changement climatique accroitra encore l'impact des sècheresses et la pression sur les ressources en eau. Le bassin méditerranéen peut donc être qualifié de "point chaud" du changement climatique. Dans ce contexte, il est important de construire des synergies entre les systèmes d'observation satellitaire et in situ des surfaces continentales et les plateformes de modélisation. Cette thèse a été réalisée en lien avec le programme international HyMEX (Hydrological cycle in the Mediterranean Experiment), consacré à l'étude du cycle de l'eau et de la prévisibilité des risques hydro- étéorologiques en Méditerranée, notamment des sècheresses. Une climatologie des variables biogéophysiques (humidité du sol, indice foliaire de la végétation ou LAI -Leaf Area Index-) et des débits des cours d'eau a été construite sur la période 1991-2008, sur une zone couvrant l'Europe, le Moyen-Orient et l'Afrique du Nord. Pour cela, des simulations du modèle du système sol-plante ISBA-A-gs et du modèle hydrologique TRIP ont été réalisées. ISBA-A-gs simule la photosynthèse et son lien avec la conductance stomatique, ainsi que le cycle annuel de la biomasse foliaire. ISBA-A-gs a été pilote par les variables atmosphériques de surface de la réanalyse ERA-Interim du CEPMMT. Le ruissellement et le drainage simules par ISBA-A-gs ont été convertis en débits des rivières par TRIP. Dans un premier temps, la qualité des forçages ERA-Interim a été évaluée sur la France a l'aide de mesures in situ du rayonnement solaire incident et de la réanalyse SAFRAN, qui fournit des précipitations fondées sur un réseau dense de mesures in situ. Des biais ont été mis en évidence sur les deux variables : ERA-Interim sous-estime les précipitations (-27%) et surestime le rayonnement solaire incident (+7%). A l'échelle de l'Europe et du bassin méditerranéen, les biais des précipitations ERA-Interim ont été corriges sur une base mensuelle à partir des précipitations du GPCC. L'impact du biais des précipitations sur la simulation des débits par TRIP a été étudié, ainsi que l'impact des différences des variables biophysiques produites par plusieurs versions du modèle ISBA (dont ISBA-A-gs). L'utilisation d'ISBA-A-gs permet une meilleure représentation des débits d'étiage et l'emploi de données satellitaires pour contraindre le LAI améliore les débits au printemps. Le volume et les variations inter annuelles des débits d'eau douce vers la Méditerranée sont en accord avec les estimations pré-existantes. Enfin, les simulations d'humidité du sol et du LAI ont été comparées aux données in situ et satellitaires disponibles durant la période 1991-2008 sur l'Europe et le bassin méditerranéen, ainsi qu'au modèle ORCHIDEE de l'IPSL. Un bon accord est observe entre (1) l'humidité superficielle du sol simulée par ISBA-A-gs et tirée des observations satellitaires micro-ondes par le projet ESA-CCI Soil Moisture, et (2) la variabilité inter annuelle du LAI simule et le LAI produit par le projet GEOLAND2. Les variations inter annuelles de l'humidité du sol et du LAI sont corrélées lors de périodes clés, mais sur des zones plus étendues avec le modèle qu'avec les observations satellitaires. / The climate of the Mediterranean basin is characterized by marked impact of the soil water deficit on vegetation growth. In these areas, frequently affected by droughts, soil moisture is a key variable for understanding the hydrological processes and the vegetation growth. Recent climatic studies have shown that climate change will probably increase the impact of droughts together with the demand for water resources in this area. As such, the Mediterranean basin is recognized as a "hot spot" of the climate change. In this context, it is important to build synergies between in situ and satellite remote sensing observing systems of the continental areas and modeling platforms. This PhD thesis was performed in the framework of the international HyMEX (Hydrological cycle in the Mediterranean EXperiment) project, which is focused on the water cycle and on the prediction of hydrometeorological hazards (and particularly droughts) over the Mediterranean basin. A climatology of the biophysical variables (soil moisture, vegetation biomass or LAI –Leaf Area Index-) and river discharges was built for the 1991-2008 period over Europe, the Middle East and North Africa. In particular, simulations were performed by the ISBA-A-gs land surface model and by the TRIP hydrological model. ISBA-A-gs simulates photosynthesis and its link with the stomatal conductance, together with the leaf biomass annual cycle. ISBA-A-gs was driven by surface atmospheric variables derived from the ECMWF ERA-Interim reanalysis. Unoff and deep drainage simulated by ISBAA- gs were converted into river discharges by the TRIP model. First, the ERA-Interim forcing was evaluated over the France domain. This evaluation was performed using in situ measurements of the incoming solar radiation (ISR) and with the SAFRAN reanalysis, which provides precipitation data based on a dense network of in situ observations. Biases were evidenced for the two variables: ERA-Interim underestimates precipitation (-27%) and overestimates ISR (+7%). At the scale of Europe and of the Mediterranean basin, ERA-Interim precipitation biases were rescaled on a monthly basis using the GPCC precipitation data. The impact of precipitation biases on the river discharges simulated by TRIP was assessed, as well as the impact of the differences in biophysical variables values generated by several versions of ISBA (including ISBA-A- s). It was shown that the use of ISBA-A-gs permits a better representation of the river discharges at low water levels. The use of satellite-derived product to force the LAI improves river discharge simulations at springtime. The river freshwater inputs (volume and interannual variability) to the Mediterranean Sea are close to pre-existent estimates. Finally, the soil moisture and LAI simulations were compared to in situ and satellite observations, available over the 1991- 2008 period over Europe and the Mediterranean basin, as well as to the IPSL ORCHIDEE model. A good agreement is observed between (1) the surface soil moisture simulated by ISBA-A-gs and derived from satellite microwave observations by the ESA-CCI Soil Moisture project, and (2) the interannual variability of the simulated LAI and of the LAI produced by the GEOLAND2 project. The interannual soil moisture and LAI variations are correlated during key period, but over larger areas with the model than with the remote sensing data

Une grande partie du patrimoine bâti provençal a été érigé à l’aide d’un matériau connu sous le nom de « Pierre du Midi ». L’exposition de ces pierres aux intempéries conduit à des dégradations particulières. Parmi celles-ci, la desquamation en plaques a la particularité de se développer en dehors des zones de remontées capillaires ainsi qu’en l’absence des facteurs communs de dégradation. Elle est donc induite par les propriétés intrinsèques du matériau. Ce travail a eu pour objectif d’en comprendre les mécanismes et d’établir le rôle joué par les minéraux argileux. La variabilité du degré de desquamation en plaques a tout d’abord été mise en évidence sur des monuments de périodes de construction équivalentes. Puis, un échantillonnage représentatif de cette variabilité a été mené en carrières. Le cortège argileux de chaque échantillon a été caractérisé en combinant la microscopie électronique en transmission, à la simulation des diffractogrammes de rayons X. La nature et la quantité de chacune des phases argileuses ont ainsi été déterminées et la quantité des feuillets expansifs peut être corrélée au degré de desquamation en plaques. Par ailleurs, les propriétés de stockage et de transfert des fluides de ces matériaux ont été évaluées. Elles ont permis d’appréhender les modalités de transport de l’eau et son impact sur les propriétés mécaniques. La combinaison de la perte de résistance mécanique et d’une forte dilatation au cours de la variation de la teneur en eau semble être à l’origine du processus de desquamation en plaques. Ce travail permet en outre de définir des critères de sélection de pierres de remplacement pertinents du point de vue de leur durabilité. / Most of the Provence built heritage was erected using a material named « Pierre du Midi ». The natural weathering of these limestones leads to specific deterioration patterns. Among these, spalling tends to develop in areas apart from capillary rise and free from the commun decay factors. This phenomenon seems induced by the intrinsic properties of the material. The present study aims to understand the mechanisms at play and to establish the role of the clay minerals. A wide variability of spalling degree has been observed on historical buildings of equivalent construction periods. A representative sampling of the different limestones types has thus been realized in the respective quarries. The clay minerals assemblage of each sample has been defined thanks to an adapted methodological approach combining TEM-EDX characterization to XRD profile modeling. It allowed determining both the nature and the quantity of each clay mineral phase. The link between the expansive layers quantity and the spalling degree has been evidenced. The storage and transport properties of the different types of limestones were also defined. Moreover, the macroscopic behavior upon water content variation was assessed through dilation and compressive strength experiences. The results suggest that the mechanism leading to spalling decay is triggered by the interaction between the expansive clay mineral layers and the water molecules. The hydromechanic behavior of the stone constitutes the macroscopic symptom of this interaction. This behavior is highly controlled by the fluid storage and transport properties that condition the macroscopic transmission of the deformation.

A subestrutura ferroviária é uma parte importante da via permanente, pois seu comportamento pode afetar significativamente o desempenho global da via, impactando em manutenção e custos. O fato é que os materiais da subestrutura, como o subleito, estão no estado não-saturado na maior parte do tempo, e suas propriedades hidromecânicas dependem diretamente do grau de saturação e dos valores de sucção. Além disso, o estado não-saturado do solo é regido pelas ações atmosféricas e climáticas, o que torna fundamental a análise da influência de características ambientais e geotécnicas, tais como a precipitação, evaporação, tipo de solo e drenagem na resposta estrutural do subleito. Países de clima tropical/subtropical, como o Brasil, possuem elevada taxa de precipitação anual, e, por isso, merecem atenção especial quando se trata da interação via-clima. Mudanças da umidade ou sucção ou da taxa de infiltração no interior do subleito podem impactar significativamente no seu estado de tensões. O principal objetivo desta pesquisa foi avaliar a influência da variação da umidade e sucção no comportamento hidromecânico de um subleito ferroviário, localizado na região costeira do estado de São Paulo, considerando-se as características geotécnicas e climáticas locais. A interação via-clima foi investigada através de análises numéricas em elementos finitos (MEF) de infiltração saturada/não-saturada, aplicando-se parâmetros determinados em laboratório e monitoramento de campo. Para as simulações numéricas foi utilizado o software SEEP/W, enquanto no monitoramento de campo foram empregados sensores de matriz granular para medição do potencial matricial no solo. A caracterização mecânica do solo de subleito se baseou em resultados de módulo de resiliência obtidos por ensaios triaxiais cíclicos, em diferentes condições e ciclos de umidade e sucção. As simulações numéricas apresentaram importantes variações da sucção no solo em função das condições geotécnicas e climáticas, verificando-se a significância dos aspectos climáticos no comportamento hidráulico e mecânico do subleito da via férrea. / The track substructure is an important part of a railway that requires attention when considering its whole global mechanical performance. Improving the long-term resistance to deformation behavior and therefore reducing maintenance problems during the operation of a track is always presented between engineers and researchers. The fact is that the substructure materials, such as the subgrade, are mostly in unsaturated state, and their hydro-mechanical properties are directly dependent on saturation degree and suction values. Besides, unsaturated state of the soil is controlled by atmospheric actions and climate conditions. Considering this, it is fundamental to analyze the influence of the environmental and geotechnical characteristics such as precipitation, evaporation, soil type, and drainage in the subgrade structural response. Countries with tropical/subtropical climate, such as Brazil, which have a high average annual precipitation rate, deserve special attention concerning climate-track interaction in railway performance. A little variation in the water content or infiltration rate into the subgrade may affects significantly their stress state. The main objective of this paper is to evaluate the influence of the water content and suction changes on mechanical behavior of a track substructure in a Brazilian coastal region, at São Paulo state, considering geotechnical characteristics and local climate. The climate-track interaction was evaluated through field monitoring and finite element numerical analysis with parameters obtained in the laboratory for all the materials involved. Numerical simulations were performed using SEEP/W software and the field monitoring was realized through granular matrix sensors (GMS). Soil mechanical characterization was based on resilient modulus values determined through cyclic triaxial tests in different moisture/suction conditions. Numerical results showed an important variation of soil suction over time in function of geotechnical and climate data. In the simulated scenario, considering tropical local climate it was observed the importance of climate aspects in the hydraulic and mechanical behavior of the geotechnical components of the railway track.

Cementproduktion står idag för totalt 5 % av koldioxidutsläppen globalt, vilket t.ex. är mer än dubbelt så mycket som den globala flygindustrin. Nya cement- och betongrecept, med nya egenskaper, utvecklas med målet att minska klimatbelastningen. I produkten Bascement ersätts delar av klimatbelastande cementklinker med mineraltillsatsen flygaska, en restprodukt från andra industrier. Detta ska alltså leda till en minskad klimatbelastning. Betong med Bascement har dock orsakat förseningar och extra kostnader i produktion på grund av långa torktider som inte stämt överens med simuleringar i TorkaS 3.2, en programvara baserad på betong med Byggcement. TorkaS ska ersättas av programvaran Produktionsplanering Betong (PPB) som kan simulera uttorkning i betong med Bascement. Målet med studien är att undersöka hur fuktsimuleringar i PPB skiljer sig jämfört med genomförda fuktmätningar i fyra betongprover med två olika vattencementtal, vct. Genom att förvara proverna i olika miljö är målet att experimentellt mäta hur omgivningen påverkar uttorkningen. Målet är vidare att visa skillnader mellan fuktsimuleringar med inbyggd klimatdata i PPB och med egna uppmätta klimatdata. Resultaten från de experimentella undersökningarna visar att uttorkningen blev större i betongprover med vct 0,40 än för motsvarande prover med vct 0,55 efter 70 dagar. Prover som hade förvarats i en stabil inomhusmiljö hade torkat mer än prover som hade förvarats i en varierande utomhusmiljö, vilket i denna studie inte stämde överens med simuleringar i PPB. Resultatet i denna studie visar att simuleringar i PPB tenderar att visa något större uttorkning jämfört med genomförda fuktmätningar. Denna överskattning blir större vid simuleringar med en varierande utomhusmiljö än med en stabil inomhusmiljö. Överskattningen blir större vid simuleringar med inbyggd klimatdata i PPB än med egna uppmätta klimatdata. Vid justering av betongens maxtemperatur i PPB till verkligt uppmätt maxtemperatur påverkas fuktsimuleringarna positivt så att de närmar sig de experimentellt erhållna resultaten. Betong med låga vct påverkas mer av en sådan justering än höga vct. Slutsatsen i denna studie är baserad på simuleringar och fuktmätningar i ett fåtal betongprover, vilka kan ha utsatts för störningar. Fler studier behövs för att validera reliabiliteten hos programvaran PPB. Val av härdningsmetod samt maxtemperatur under härdning kan påverka uttorkningen och simuleringar i PPB. Experimenten indikerar att simuleringar med PPB tenderar att avvika om betong med höga vct utsätts för vattentillskott kort efter gjutning. Korrekt maxtemperatur i PPB är viktigt för en mer verklig simulering av uttorkning i betong, särskilt vid låga vct. Simuleringar i PPB tenderar att bli mer korrekta med egna klimatdata än med inbyggd klimatdata. / Cement production currently accounts for a total of 5 % of carbon dioxide emissions globally, which for example is more than twice as much as the global aviation industry. New cement and concrete recipes, with new properties, are being developed with the aim of reducing the climate load. In the Portland fly ash cement, parts of climate-stressing cement clinkers are replaced with the mineral-added fly ash, a residual product from other industries. This should lead to a reduced climate impact. Concrete with Portland fly ash cement, however, has caused delays and extra costs in production due to long drying times that did not match with simulations in the software TorkaS 3.2, which is based on concrete with Portland-limestone cement. TorkaS will be replaced by the software Production Planning Concrete, PPB, which can simulate dehydration in concrete with Portland fly ash cement. The aim of the study is to investigate how moisture simulations in PPB differ from executed moisture measurements in four concrete samples with two different w/c ratio. By storing the samples in different environments, the goal is to experimentally measure how the environment affects the dehydration. The goal is also to show differences between moisture simulations with the built-in climate data in PPB and with the own measured climate data. The results from the experimental studies show that the dehydration became larger in concrete samples with w/c ratio 0.40 than for samples with w/c ratio 0.55 after 70 days. Samples that had been stored in a stable indoor environment had dried more than samples that had been stored in a varying outdoor environment, which in this study did not correspond to simulations in PPB. The result of this study shows that simulations in PPB tend to show slightly greater dehydration than executed moisture measurements. This overestimation is greater in simulations with a varying outdoor environment than with a stable indoor environment. The overestimation is greater in simulations with the built-in climate data in PPB than with the own measured climate data. When adjusting the maximum temperature of the concrete in PPB to the actual measured maximum temperature, the moisture simulations is positively affected so that they approach the experimentally obtained results. Concrete with low w/c ratio is more affected by such an adjustment than concrete with high w/c ratio. The conclusion in this study is based on simulations and moisture measurements in a few concrete samples, which may have been exposed to disturbances. More studies are needed to validate the reliability of the PPB software. Choice of curing method and maximum temperature during curing can affect the drying and simulations in PPB. The experiments indicate that simulations with the PPB software tend to deviate if concrete with a high w/c ratio is exposed to water shortly after casting. Correct maximum temperature in PPB is important for a more real simulation of dehydration in concrete, especially at high w/c ratio. Simulations in PPB tend to be more accurate when using own climate data than using the built-in climate data.