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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Les Centres sidérurgiques des rivages de la mer du Nord et leur influence sur l'organisation de l'espace Brême, IJmuiden, Gand, Dunkerque : recherches sur l'expression et sur la signification géographiques de l'activité industrielle /

Malézieux, Jacques. January 1981 (has links)
Thesis (doctoral)--Université de Paris I, Panthéon-Sorbonne, 1979. / Includes bibliographical references (p. 959-1004).
62

Variabilité des concentrations cellulaires phytoplanctoniques de diméthylsulfoniopropionate (DMSP) et de diméthylsulfoxyde (DMSO) en Baie Sud de la Mer du Nord

Speeckaert, Gaelle 21 November 2018 (has links) (PDF)
The eutrophication of the Southern Bight of the North Sea has been benefitting to the prymnesiophyte Phaeocystis globosa (P. globosa). This species is a known high dimethylsulfoniopropionate (DMSP) producer whose bloom accounts for 95% of spring phytoplankton biomass. An increase in DMS(P) and its oxidation product dimethylsulfoxide (DMSO) cellular contents have been frequently observed in cellular stress conditions. To test this, we have first analysed the natural distribution of DMS(P,O) cellular contents in the North Sea. Secondly, we have measured DMS(P,O) cellular contents in monospecific cultures of several key species of the North Sea and their responses to salinity variations. Our main working hypothesis is that DMSP acts as an osmoregulator and/or as an antioxidant, depending on the species. The DMS(P,O) annual cycle in the Southern Bight of the North Sea revealed a seasonality linked to the spring phytoplankton communities succession: (1) colonial diatoms (reappearing in autumn), (2) Chaetoceros spp. (3) P. globosa, (4) large-size summer diatoms (mainly Guinardia spp.), and (5) dinoflagellates. Spatial gradients of DMS(P) were related to those of phytoplankton biomass, itself related to the inputs of nutrients from the Scheldt estuary. It also discharges suspended matter in which DMSO may have been produced by anaerobic oxidation of DMS. Laboratory measurements confirmed a large variability in DMSP cellular contents between the six studied diatoms (Nitzschia closterium, Skeletonema costatum, Thalassiosira rotula, Chaetoceros socialis, Chaetoceros debilis, and Guinardia delicatula), low producers in comparison with P. globosa and even more with Heterocapsa triquetra (Dinoflagellate). In particular, communities 2 and 4 have lower DMSP cellular contents than community 1 (N. closterium, S. costatum and T. rotula). Senescence induces a decrease in DMSP/DMSO suggesting an oxidative stress caused by nutrients and/or light limitation in DMSP producers. In S. costatum, DMSP seems to play an osmoregulatory role and is oxidised into DMSO in hyposaline conditions. In P. globosa and H. triquetra, an oxidative stress appears in hypo- and hypersaline conditions diverging from their salinity optimum. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
63

Target strength variability in Atlantic herring (Clupea harengus) and its effect on acoustic abundance estimates

Fässler, Sascha M. M. January 2010 (has links)
Acoustic survey techniques are widely used to quantify abundance and distribution of a variety of pelagic fish such as herring (Clupea harengus). The information provided is becoming increasingly important for stock assessment and ecosystem studies, however, the data collected are used as relative indices rather than absolute measures, due to the uncertainty of target strength (TS) estimates. A fish’s TS is a measure of its capacity to reflect sound and, therefore, the TS value will directly influence the estimate of abundance from an acoustic survey. The TS is a stochastic variable, dependent on a range of factors such as fish size, orientation, shape, physiology, and acoustic frequency. However, estimates of mean TS, used to convert echo energy data from acoustic surveys into numbers of fish, are conveniently derived from a single metric - the fish length (L). The TS used for herring is based on TS-L relationships derived from a variety of experiments on dead and caged fish, conducted 25-30 years ago. Recently, theoretical models for fish backscatter have been proposed to provide an alternative basis for exploring fish TS. Another problem encountered during acoustic surveys is the identification of insonified organisms. Trawl samples are commonly collected for identification purposes, however, there are several selectivity issues associated with this method that may translate directly into biased acoustic abundance estimates. The use of different acoustic frequencies has been recognised as a useful tool to distinguish between different species, based on their sound reflection properties at low and high frequencies. In this study I developed theoretical models to describe the backscatter of herring at multiple frequencies. Data collected at four frequencies (18, 38, 120 and 200 kHz) during standard acoustic surveys for herring in the North Sea were examined and compared to model results. Multifrequency backscattering characteristics of herring were described and compared to those of Norway pout, a species also present in the survey area. Species discrimination was attempted based on differences in backscatter at the different frequencies. I examined swimbladder morphology data of Baltic and Atlantic herring and sprat from the Baltic Sea. Based on these data, I modelled the acoustic backscatter of both herring stocks and attempted to explain differences previously observed in empirical data. I investigated the change in swimbladder shape of herring, when exposed to increased water pressures at deeper depths, by producing true shapes of swimbladders from MRI scans of herring under pressure. The swimbladder morphology representations in 3-D were used to model the acoustic backscatter at a range of frequencies and water pressures. I developed a probabilistic TS model of herring in a Bayesian framework to account for uncertainty associated with TS. Most likely distributions of model parameters were determined by fitting the model to in situ data. The resulting probabilistic TS was used to produce distributions of absolute abundance and biomass estimates, which were compared to official results from ICES North Sea herring stock assessment. Modelled backscatter levels of herring from the Baltic Sea were on average 2.3 dB higher than those from herring living in northeast Atlantic waters. This was attributed to differences in swimbladder sizes between the two herring stocks due to the lower salinity Baltic Sea compared to Atlantic waters. Swimbladders of Baltic herring need to be bigger to achieve a certain degree of buoyancy. Morphological swimbladder dimensions of Baltic herring and sprat were found to be different. Herring had a significantly larger swimbladder height at a given length compared to sprat, resulting in a modelled TS that was on average 1.2 dB stronger. Water depth, and therefore the increase in ambient pressure, was found to have a considerable effect on the size and shape of the herring swimbladder. Modelled TS values were found to be around 3 dB weaker at a depth of 50 m compared to surface waters. At 200 m, this difference was estimated to be about 5 dB. The Bayesian model predicted mean abundances and biomass were 23 and 55% higher, respectively, than the ICES estimates. The discrepancy was linked to the depth-dependency of the TS model and the particular size-dependent bathymetric distribution of herring in the survey area.
64

Évaluation des flux sédimentaires sur le littoral du Nord-Pas de Calais : vers une meilleure compréhension de la morphodynamique des plages macrotidales / In situ sediment transport measurements on the coast of Northern France : towards a better understanding of the morphodynamics of macrotidal barres beaches

Cartier, Adrien 13 December 2011 (has links)
Nos connaissances et notre compréhension de la dynamique sédimentaire des plages macrotidales sont encore limitées de nos jours en raison d'un manque de données lié à la plus faible proportion de ces plages à l'échelle mondiale. Trois plages macrotidales à barres et à bâches du littoral de la Côte d'Opale dans le Nord de la France ont été choisies pour mener cette étude. Elle se base sur trois approches différentes visant à caractériser (1) le régime tidal et les conditions hydrodynamiques, (2) la morphologie de la zone intertidale et (3) les flux sédimentaires longitudinaux (FL) et transversaux (FC) dans diverses conditions tidales et énergétiques. Le transport a été mesuré dans la zone proche du déferlement à l’aide de pièges à sédiment de type Kraus (1987) permettant de caractériser le débit solide à plusieurs niveaux au dessus du fond au cours de conditions d'agitation faibles à modérées (Hs < 1 m). Malgré une uniformité des flux le long de la plage, les phénomènes de vidange des bâches par l’intermédiaire de chenaux perpendiculaires au trait de côte permettent l’introduction de volumes de sédiment significatifs, augmentant localement le FL. La distribution des flux à travers l’estran présente, quant à elle, une décroissance nette du bas de plage vers le haut de plage. Les mesures simultanées de FL et de FC ont démontré que le FC dirigé vers le haut de plage et la résultante du FC sont dans la plupart des cas supérieurs aux FL en raison de la plus forte intensité des vitesses de courant oscillatoire. Ces résultats mettent en évidence des mouvements significatifs de volume de sable à travers la zone intertidale à l’échelle de la mesure, ce qui influence fortement la morphodynamique de la plage. L’ensemble de la zone intertidale est toutefois apparue relativement stable, avec des changements plus significatifs à court terme qu'à plus long terme. Les mesures de transport ont permis de mettre en lumière le rôle fondamental des bâches dans la dynamique des plages macrotidales. Ces dépressions inter-barres sont en effet responsables de la canalisation du sédiment le long du rivage, limitant ainsi les transports sédimentaires transversaux et par conséquent la migration des barres intertidales. Il est vraisemblable que le temps de résidence et l'intensité des processus hydro-sédimentaires jouent un rôle prépondérant dans la dynamique des barres intertidales. Les mesures ont également été comparées avec plusieurs estimations du transport sédimentaire issues de modèles numériques et morphodynamiques. Bien que les flux calculés surestiment en général le transport mesuré, certaines formules semblent plus adaptées pour déterminer le FL dans la zone de levée. / Our knowledge and understanding of the sediment dynamics of sandy macrotidal beaches is still limited by a lack of data from these macrotidal environments. This limitation is due to the relatively small proportion of macrotidal coasts in the world. Three sandy beaches on the coast of Northern France were chosen to conduct this study. Three scientific approaches were used: 1) characterization of tidal and waves energy conditions using wave and current meters deployed on the foreshore; 2) beach morphology survey and 3) estimation of longshore (FL) and cross-shore (FC) sediment transport using streamer traps similar to those designed by Kraus (1987). Sand transport was measured about 1 m water, next to the breaker zone and either in the shoaling zone or in the surf zone; under low to moderate waves energy conditions (Hs < 1 m). In spite of a low longshore variability in sediment transport due to a high degree of hydrodynamic uniformity along the shore, runnel drainage can locally increase sediment transport rates. Cross-shore distribution appeared to be more variable as sediment transport decreased from the lower to the upper part of the beach. Onshore, offshore and longshore sediment transport measured simultaneously showed that under various energetic conditions, FC appeared to be generally higher than FL. Although net littoral drift is directed towards the Belgian coast, these results suggest that significant volumes of sand move across the intertidal zone. These significant volumes of sand most likely have a strong influence on the morphodynamics of the beach. Daily topographical survey has shown little morphological variations while sediment transport rates appeared very variable and very significant, especially during the highest wave energy conditions. Sediment transport measurements across the foreshore highlight the important role played by inter-bar troughs in the morphodynamics of macrotidal beaches. Higher bed roughness in these depressions is responsible for an increase in sediment resuspension through the water column. Suspended transport is therefore favoured in troughs and hinders the cross-shore sediment transport, which is responsible for the bar migration across the intertidal zone. Morphological changes are dependent of the time residence of the hydrodynamic zones, but the morphodynamics of the intertidal bars appear to be strongly controlled by the amplitude of the incident waves. FL were also compared with calculated data computed using from numerical and morphodynamic model. Although computed transport rates are generally higher than in situ measurements, it appears that some formulae provide better estimate of FL, especially in the shoaling zone
65

Changements ontogéniques de la condition larvaire chez une espèce de poisson à reproduction hivernale, le hareng des Downs / Ontagenetic shift in the larval condition of Downs herring, a winter spawning fish

Denis, Jeremy 13 December 2016 (has links)
La condition des larves de hareng des Downs durant la période critique a été caractérisée entre 2008 et 2015, en Manche orientale et dans la Baie sud de la Mer du Nord à partir des données collectées, durant la campagne International Bottom Trawl Surveys (IBTS). Tout d'abord, l'étude de la stratégie alimentaire, à partie de l'observation des proies dans les contenus digestifs par deux méthodes complémentaires (microscopie électronique et mesure de la fluorescence) a montré un changement de régime en fonction de la taille. Les larves inférieures à 13 mm avaient un régime omnivore très diversifié et composé de protistes et de petites proies zooplanctoniques, tandis que les larves plus grandes avaient un régime moins diversifié et composé principalement de plus grandes proies zooplanctoniques. En parallèle du changement de régime alimentaire, la combinaison de quatre indices de condition (taux d'ingestion, rapports ARN/ADN et ADN/C et otolithes) à l'échelle individuelle a également révélé un changement de l'état nutritionnel et de la croissance de ces larves. Les larves inférieures à 13 mm avaient une nutrition et une croissance soutenues, tandis que la croissance des larves plus grandes était faible. Ceci peut traduire un changement dans la stratégie d'allocation de l'énergie à partir de 13 mm, qui serait plus orientée vers du stockage que vers de la croissance. Ces changements ontogéniques dans la condition larvaire suggèrent que le changement de régime alimentaire qui s'opère à partir de 13 mm, pourrait constituer le coeur de la période critique pour les larves de hareng des Downs. / The larval condition of Downs herring during the critical period was investigated between 2008 and 2015 in the eastern English Channel and Southern Bight of North Sea from data collected during the International Bottom Trawl Survey (IBTS). First, the study of the feeding strategy from gut contents analysis using two complementary approaches (electronical microscopy and measure of fluorescence) revealed a shift in the feeding diet occuring at a larval size of 13 mm. Smaller larvae had an omnivorous and a more diversified diet composed of numerous protists and small zooplanktonic preys whereas bigger larvae had a less diversified diet composed mainly of bigger zooplanktonic prey. Along with the diet shift, combination of four condition indices (ingestion rate, RNA/DNA and DNA/C ratios and otoliths) also revealed important changes in the nutritional status and growth of these larvae. Larvae smaller than 13 mm had a sustainable nutrition and growth whereas larger larvae depicted low growth rate. This could reflect a change in the energy-allocation strategy from a growth-oriented strategy towards a more storage-oriented strategy. These ontogenetic changes in the larval condition suggest that the diet shift occurring at 13 mm could constitute the core of the critical period for Downs herring larvae.
66

Etude biostratigraphique des assemblages de diatomées pyritisées des sédiments du Paléocène supérieur et de l'Eocène inférieur des Bassins Danois, de Dieppe-Hampshire et Belge - apports paléoenvironnementaux/Biostratigraphic study of the pyritised diatom assemblages from the Upper Paleocene and Lower Eocene sediments of the Danish, Dieppe-Hampshire and Belgian Basins

Van Eetvelde, Yoann 15 June 2005 (has links)
La distribution stratigraphique des diatomées pyritisées et leur répartition paléogéographique sont étudiées dans les sédiments du Paléocène supérieur et principalement de l’Eocène inférieur des Bassins Danois (Ølst et Hinge), de Dieppe-Hampshire (Saint-Josse et Ailly) et Belge (Knokke). Différents types de fossilisation ont été observés. D’une part, dans un stade précoce de la diagenèse, un moulage du frustule est construit par la croissance de minéraux authigéniques (pyrite et barytine). D’autre part, le frustule siliceux est remplacé épigénitiquement par de la pyrite. Ces deux processus de fossilisation, pouvant coexister, gardent les diatomées identifiables. Une méthodologie fiable et reproductible pour l’extraction de ces dernières a été mise en point. Une évolution des zones de diatomées (zonation) est mise en évidence : quatre zones (D0 à D3) d’association ou d’abondance et deux sous-zones (D3a et D3b) sont reconnues. Cette zonation est établie pour les bassins méridionaux et orientaux du Bassin de la Mer du Nord. Elle est corrélable avec les biozonations de King (1983), Fenner (1985), Mudge & Copestake (1992a) et Mitlehner (1994, 1996) valables pour la partie centrale du Bassin de la Mer du Nord. Les zones D0 à D3 autorisent les corrélations entre les unités lithostratigraphiques des différents bassins étudiés et celui de la Mer du Nord. Cela a permis, entre autres, de corréler les sédiments des faciès sparnaciens du Bassin de Dieppe-Hampshire aux formations de la Mer du Nord. Enfin, les diatomées pyritisées sont un nouvel argument pour encadrer la position de la C.I.E. (dont la base est le critère de reconnaissance de la limite Paléocène-Eocène), celle-ci étant située dans la partie inférieure de la zone D1 sous le pic d’abondance de l’espèce Coscinodiscus morsianus var. moelleri. / The stratigraphic distribution of the pyritized diatoms and their paleogeographic repartition are studied in Upper Paleocene and especially Lower Eocene from the Danish (Ølst Hinge), Dieppe-Hampshire (Saint-Josse and Ailly) and Belgian (Knokke) Basins. Different kinds of fossilisation are observed. In a first step of the diagenesis, a mould of the frustule is built thanks to the growth of authigenic minerals (pyrite and barite). The siliceous skeleton may also be completely replaced epigenetically by pyrite. These two types of fossilisation, that may coexist, keep diatoms identifiable. A reliable and reproducible methodology for the extraction of pyritized diatoms has been developed. The evolution of the diatom zones is underlined : four zones (D0 until D3) of association or abundance are recognized. This zonation is established for the southern and eastern basins of the North Sea Basin. It is interrelated with the biozonations of King (1983), Fenner (1985), Mudge & Copestake (1992a) and Mitlehner (1994, 1996) valid for the central part of the North Sea Basin. The zones D0-D3 allow correlations between the lithostratigraphic units of the various studied basins and the one of the North Sea. This enables among others to correlate the sediments of the sparnacien facies of the Dieppe-Hampshire with the formations of the North Sea. At last, the pyritized diatoms represent a new argument to locate the C.I.E. which base is the criterion for the identification of the Paleocene-Eocene boundary. The C.I.E. is located in the lower part of the D1 zone under the abundance peak of the Coscinodiscus morsianus var. moelleri species.
67

A reconnaissance geophysical survey of the North, Norwegian, Greenland, Kara and Barents Seas and the Arctic Ocean

Vogt, Peter R. January 1968 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 127-133).
68

En merkantilistisk början : Stockholms textila import 1720–1738 / A Mercantilistic Beginning : The Import of Textiles to Stockholm 1720-1738

Aldman, Lili-Annè January 2008 (has links)
<p>The purpose of this thesis is to, from an institutional approach, study how the Stockholm importers within the textile sector adapted their foreign trade to the change in economic policy 1720 through 1738. The focus is to investigate to what extent the introduction of new laws, regulations etc. can be an explanation for what happened to Stockholm’s foreign trade, mainly imports, particularly textile imports during the period. It is mainly the economic policies that had been enacted during the Hornian government and their effects that have been studied. This is a period that has seldom been studied in other research.</p><p>This thesis begins when the Russian raids were over. This was a year when the foreign trade still was relatively free and was untouched by the 17th century’s regulations. After 1721 the policies that would be introduced to increase Sweden's level of self-sufficiency and strengthen ties with the North Sea area had several components. Besides the economic policy, the main sources for the thesis are the city toll records.</p><p>The trade policies in the shape of tolls and fees, import and consumption bans etc. and the commercial policies together became different kinds of political tools used for several purposes. The conclusion of this thesis is that the economic policies made the Stockholm importers adapt their trade to the change. The import bans and sumptuary laws had an effect. The economic policies gave rise to an increase in the import of textile raw materials. The rise in toll costs and import fees contributed to displacing the foreign trade towards other areas. The change in the economic policies was successful in the sense that it gave rise to new conditions for domestic production within the textile sector and forced Stockholm's importers to adapt their foreign trade.</p>
69

Réservoirs silicoclastiques très enfouis : caractérisation diagénétique et modélisation appliquées aux champs pétroliers du Viking Graben (Mer du Nord) / Deeply buried siliciclastic reservoirs : diagenetic characterization and modelling of oil fields in the Viking Graben (North sea)

Ong, Anthony 06 May 2013 (has links)
Dans les réservoirs silicoclastiques, la perte de porosité avec l'enfouissement est due à la fois à la compaction mécanique lors des 2-3 premiers kilomètres d'enfouissement, à la compaction chimique, et à la précipitation minérale (quartz, argiles, carbonates). Dès lors, la compréhension des processus responsables de l'inhibition de la compaction et/ou de la cimentation représente un triple enjeu: i) contribuer à la connaissance des mécanismes d'interactions eau-hydrocarbures-solides en milieu diagénétique profond; ii) apporter de nouveaux arguments pour reconstituer les chemins de migration des fluides à l'échelle du bassin iii) développer des guides de prospection pour l'industrie pétrolière. Les techniques analytiques telles que la pétrographie quantitative, les inclusions fluides ainsi que les modélisations diagénétiques et de bassin ont été couplées afin de comprendre les processus régissant le contrôle de la qualité du réservoir du Brent (Jurassique Moyen) à travers 8 champs pétroliers (et 11 puits) dans le bloc Q3 (Viking Graben, Northern North Sea). L'étude pétrographique quantitative du réservoir du Tarbert a permis de définir des compositions minéralogiques et des paramètres pétrophysiques (porosité) relativement similaires sur les 183 échantillons étudiés. Une paragenèse diagénétique commune à tous les champs étudiés a été établie, dominée par les ciments de quartz, de deux générations de kaolinite (K1, associée à la déstabilisation des micas et K2, associée à la dissolution des feldspaths potassiques), et de précipitation d'illite. L'approche comparative des ciments d'enfouissement n'a pas permis de rendre compte des larges gammes de porosité et perméabilité mesurées allant de 8 à 27 % et de 0,2 à 5000 mD. Contrairement au modèle diagénétique souvent évoqué, l'inhibition des ciments de quartz ne joue pas un rôle majeur dans la préservation de la porosité des réservoirs du bloc Q3. Les estimations P-V-T-X-t du piégeage des inclusions fluides couplées au modèle de bassin ont permis de reconstituer trois chemins de migration des fluides aqueux et hydrocarbonés associés à la mise en place de surpressions fluides au sein des réservoirs du Tarbert. 1) La partie Nord de la kitchen du Viking Graben alimente les champs de Hild, Jura et Islay en huiles légères très précocement (65-42 Ma) et en gaz à condensat à partir de 35-15 Ma. Ces deux migrations sont associées à une montée en surpression fluide du réservoir de 100 à 200 bar. 2) la partie Est de la kitchen de l'East Shetland alimente les champs d'Alwyn, Dunbar, et Grant en huiles lourdes à légères à partir de 42-35 Ma, associée à une faible surpression fluide (30-40 bar). 3) la partie Sud de la kitchen de l'East Shetland (longue distance de migration) alimente quant à elle les champs de Forvie Central et North très tardivement en gaz à condensat (> 15 Ma). Le timing relatif entre la mise en place de la surpression fluide et l'avancement de la compaction mécanique/chimique s'est révélé être le paramètre de premier ordre régissant la préservation de la porosité des réservoirs observée dans le bloc Q3. La présence d'inclusions hydrocarbonées atypiques HT-BP (haute température-basse pression) datées du Jurassique supérieur dans les champs proches du Viking Graben, pourrait être à l'origine d'une génération d?hydrocarbures très précoce sous un régime de pression hydrostatique. Bien que n'ayant aucun impact sur l'inhibition de la contrainte effective, cette migration fluide pourrait être attribuée aux anomalies thermiques du Nord-Ouest de l'Europe liée à l'ouverture de l'Atlantique Nord. Le couplage des outils de pétrographie quantitative, inclusions fluides et modélisation de bassin a donc permis de soulever l'importance d'intégrer une vision régionale à l'étude ponctuelle de la diagenèse dans le but de comprendre le rôle des migrations fluides sur la préservation de la qualité des réservoirs silicoclastiques / In siliciclastic reservoirs, porosity loss is mainly due to the mechanical compaction in the first 2-3 km of burial, the chemical compaction and mineral precipitation (quartz, clays, carbonates). Therefore, understanding the processes responsible of the inhibition of compaction and/or cementation permits to: i) contribute to the knowledge of the water-hydrocarbon-solid interaction mechanisms in deep diagenetic environment, ii) give new arguments for the reconstruction of fluid pathways at the basin scale iii) assist the oil industry for the intensive exploration. Analytical techniques such as quantitative petrography, fluid inclusion and basin/diagenesis modelling were coupled across 8 oil fields (and 11 wells) located in the Q3 block (Viking Graben, Northern North Sea) in order to understand the processes driving the variation of the Brent reservoir quality (Middle Jurassic). Quantitative petrographic study of Tarbert reservoir allowed to define similar depositional settings (mineralogy, porosity) among the 183 studied samples. The common diagenetic paragenesis is dominated by quartz cement, two generations of kaolinite (K1, associated with the destabilization of micas and K2, associated with the dissolution of feldspars), and precipitation of illite. The petrographic data do not explain the wide range of measured porosity and permeability on plugs from 8 to 27% and from 0.2 to 5000 mD respectively. In contrast with the conventional diagenetic model, the present study shows that inhibition of quartz cements did not play a major role in the preservation of porosity in the Q3 block. P-V-T-X-t estimates of fluid inclusion trapping coupled with basin modelling allowed reconstruction of three fluid migration pathways, associated with fluid overpressures in the Tarbert reservoir. 1) The northern part of the Viking Graben kitchen supplies Hild, Jura and Islay fields with an early migration of light oils (65-42 m.y.) and condensate from 35-15 m.y. Both migrations are associated with a great fluid overpressure from 100 to 200 bar. 2) The eastern part of the East Shetland kitchen supplies Alwyn, Dunbar, Grant fields, with heavy to light oils from 42-35 m.y., associated with a low fluid overpressure (30-40 bar). 3) The southern part of the East Shetland kitchen (long distance migration) supplies Forvie North and Central fields with a very late gas condensate migration (> 15 Ma). The relative timing of the fluid overpressure build-up with the degree of mechanical and chemical compaction appears to be the first order parameter governing the preservation of reservoir porosity across the Q3 block. The presence of unusual HT-LP (high temperature-low pressure) hydrocarbon inclusions in the fields near the graben could indicate an early heavy oil generation under hydrostatic pressure conditions. Although having no impact on the inhibition of effective stress, this high-temperature fluid migration could be attributed to thermal anomalies in the Northwest of Europe related to the North Atlantic opening. The combination of quantitative petrography, fluid inclusion and basin modelling allowed to point out the impact of regional fluid migrations on the well scale diagenesis and on the siliciclastic reservoir quality preservation
70

En merkantilistisk början : Stockholms textila import 1720–1738 / A Mercantilistic Beginning : The Import of Textiles to Stockholm 1720-1738

Aldman, Lili-Annè January 2008 (has links)
The purpose of this thesis is to, from an institutional approach, study how the Stockholm importers within the textile sector adapted their foreign trade to the change in economic policy 1720 through 1738. The focus is to investigate to what extent the introduction of new laws, regulations etc. can be an explanation for what happened to Stockholm’s foreign trade, mainly imports, particularly textile imports during the period. It is mainly the economic policies that had been enacted during the Hornian government and their effects that have been studied. This is a period that has seldom been studied in other research. This thesis begins when the Russian raids were over. This was a year when the foreign trade still was relatively free and was untouched by the 17th century’s regulations. After 1721 the policies that would be introduced to increase Sweden's level of self-sufficiency and strengthen ties with the North Sea area had several components. Besides the economic policy, the main sources for the thesis are the city toll records. The trade policies in the shape of tolls and fees, import and consumption bans etc. and the commercial policies together became different kinds of political tools used for several purposes. The conclusion of this thesis is that the economic policies made the Stockholm importers adapt their trade to the change. The import bans and sumptuary laws had an effect. The economic policies gave rise to an increase in the import of textile raw materials. The rise in toll costs and import fees contributed to displacing the foreign trade towards other areas. The change in the economic policies was successful in the sense that it gave rise to new conditions for domestic production within the textile sector and forced Stockholm's importers to adapt their foreign trade.

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