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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

Leichte verformungsoptimierte Schalentragwerke aus mikrobewehrtem UHPC am Beispiel von Parabolrinnen solarthermischer Kraftwerke

Kämper, Christoph, Stallmann, Tobias, Forman, Patrick, Schnell, Jürgen, Mark, Peter 21 July 2022 (has links)
Parabolrinnen-Kraftwerke sind zurzeit die am häufigsten zum Einsatz kommende und wirtschaftlichste Technologie solarthermisch konzentrierender Systeme (Concentrated Solar Power – CSP) und gehören zu den linienfokussierenden Systemen [1]. In Spanien stellen die solarthermischen Parabolrinnen-Kraftwerke Andasol 1–3 mit einer Kollektorfläche von ca. 150 Millionen m² bereits 150 MW zur Verfügung, mit denen ca. 200.000 Einwohner jährlich mit Strom versorgt werden können [2]–[4]. Das Solarfeld besteht aus ca. 150 m langen, in Reihe angeordneten Kollektoren, die aus einzelnen Parabolrinnen-Kollektormodulen zusammengefasst und im Tagesverlauf der Sonne nachgeführt werden. Die Lagerung erfolgt an den Modulrändern im Schwerpunkt des Kollektormoduls, der mit der Rotationsachse zusammenfällt. Bisher werden die Kollektoren überwiegend als filigranes Stahlfachwerk mit über die Aperturweite parabelförmig, uniaxial gekrümmten und punktuell gestützten Spiegelelementen ausgeführt. Bei der Assemblierung der Stahlfachwerke und der Spiegelelemente ist schon im Bauzustand durchgehend eine hohe Präzision gefordert, um eine maximale Solarstrahlenkonzentration der einfallenden direkten solaren Strahlung auf ein in der Fokallinie befindliches Absorberrohr sicherzustellen [5]. In diesem wird ein Wärmeträgermedium, zumeist Thermoöl, auf eine Prozesstemperatur von ca. 400 °C erhitzt. In einem nachgeschalteten konventionellen Kraftwerksblock wird mittels Dampfturbine Elektrizität erzeugt. Das bisher kommerziell meist genutzte Kollektormodul ist der EuroTrough mit einer Aperturweite von ca. 5,80 m und einer Modullänge von 12 m [6], [7] (Bild 1), welches als Benchmark für die erste Förderphase des Projekts diente. Zur Verbesserung der Wirtschaftlichkeit zielen bisherige Entwicklungen auf eine Vergrößerung der Spiegelfläche zur Steigerung des Wirkungsgrades über einen erhöhten geometrischen Konzentrationsgrad, definiert als das Verhältnis von Reflektor- zu Absorptionsfläche, ab. Module wie der UltimateTrough und der SpaceTube erreichen dies durch die Vergrößerung der Aperturweite auf 7,5 m bzw. 8 m [8], [9]. Ein alternatives Strukturkonzept aus stahlfaserverstärkten Betonfertigteilen der Schweizer Firma Airlight mit einer Aperturweite von 9,7 m besteht aus durch Luftdruck in parabolische Form gebrachten Spiegelfolien als Reflektorsystem und wurde bisher in einem Pilot-Kraftwerk in Ait-Baha, Marokko, umgesetzt [10]. Wesentliche Arbeiten der zweiten Förderphase sind daher – dem Trend zu größerer Apertur folgend – an der visionären Entwicklung von Parabolschalen mit Öffnungsweiten von bis zu 10 m ausgerichtet. [Aus: Einleitung] / Parabolic trough power plants are currently the most frequently used and most economical technology of solar thermal systems (Concentrated Solar Power – CSP) and belong to the linear focus collector types [1]. In Spain, the solar thermal parabolic trough power plants Andasol 1–3 with a collector area of approx. 150 million m² already provide 150 MW, which means that approx. 200,000 inhabitants can be annually supplied with electricity [2]–[4]. The solar field consists of approx. 150 m long collectors arranged in rows, which are combined from individual parabolic trough collector modules and track the sun during the course of the day. The bearings are located at the edges of the module in the centre of gravity of the collector module, which corresponds to the axis of rotation. Up to now, the collectors have mainly been designed as a steel framework with parabolic, uniaxially curved and pointwise supported mirror elements. During the assembly of the steel framework and the mirror elements, high precision is required throughout the manufacturing in order to ensure a maximum solar radiation concentration of the incident direct solar radiation on an absorber tube located in the focal line [5]. A heat transfer medium, usually thermal oil, is heated to a process temperature of approx. 400 °C in the absorber tube. Electricity is generated in a downstream conventional power plant unit by means of a steam turbine. The most commercially used collector module is the EuroTrough with an aperture width of approx. 5.80 m and a module length of 12 m [6], [7] (Fig. 1), which served as a benchmark for the first funding phase of the project. In order to improve economic efficiency, previous developments have aimed to increase the size of the mirror surface in order to increase efficiency by a higher geometric degree of concentration, defined as the ratio of reflector surface to absorption surface. Modules like the UltimateTrough and the SpaceTube achieve this by increasing the aperture width to 7.5 m or 8 m, respectively, [8], [9]. An alternative structural concept consisting of prefabricated steel fibre-reinforced concrete elements from the Swiss company Airlight with an aperture width of 9.7 m consists of parabolic mirror foils as a reflector brought into parabolic shape by air pressure and has already been implemented in a pilot power plant in Ait-Baha, Morocco [10]. Therefore, in line with the trend towards a larger aperture, major work in the second funding phase aims at the visionary development of parabolic shells with aperture widths of up to 10 m. [Off: Introduction]
62

The Evolution from Late Miocene West Salton Detachment Faulting to Cross-Cutting Pleistocene Oblique Strike-Slip Faults in the SW Salton Trough, Southern California

Steely, Alexander N. 01 May 2006 (has links)
Field studies in the southwest Salton Trough between Yaqui Ridge and Borrego Mountain show that the West Salton detachment fault was active during the Pliocene and may have initiated during the latest Miocene. At Yaqui Ridge dominantly east-directed extension is recorded by slickenlines on the NW-striking detachment fault, and shows that the fault is actually a low-angle dextral oblique strike-slip fault. Crustal inheritance is responsible for the position of the fault at Yaqui Ridge, which reactivates a late Cretaceous reverse -sense mylonite zone at map scale. Late Miocene to Pliocene basin fill deposits at Borrego Mountain display progressive unconformities, contain detritus shed from the footwall and damage zone of the West Salton detachment fault, record the growth of a large hanging wall anticline, and document the initiation and evolution of the West Salton detachment fault. The Borrego Mountain anticline is a major hanging wall growth fold that trends - N60 °W and has at least 420 m of structural relief. The late Quaternary Sunset conglomerate is - 600 m thick, lies in angular unconformity on Pliocene basin fill, is bound on the SW by the dextral oblique Sunset fault, and coarsens upward and SW toward the fault. It is dominated by plutonic lithologies from nearby areas, contains up to 10% recycled sandstone clasts from Pliocene deposits, and was shed from the SW side of the then-active Sunset fault. Based on lithologic, stratigraphic, compositional similarities, we correlate this conglomerate to part of the - 1. I - 0.6 Ma Ocotillo Formation. The West Salton detachment fault was folded and deactivated at Yaqui Ridge by the dextral oblique San Felipe fault zone starting - 1. l - 1.3 Ma. The Sunset fault is in the middle of a complex left stepover between the San Felipe fault to the NW and the Fish Creek Mountains fault to the SE. Structural analyses and mapping show that syntec tonic conglomerate, the West Salton detachment fault, and footwall crystalline rocks all have similar fold geometries and record similar amounts of NE-SW shortening. The dominant SE-trending population of slip vectors on the Sunset fault is not present on the West Salton detachment fault and suggests limited or no activation of the older detachment fault by the younger fault zone.
63

EXPERIMENTAL STUDIES OF THE SATURATION LEVEL OF METHANE HYDRATE IN THE EASTERN NANKAI TROUGH SEDIMENTS

Kawasaki, Tatsuji, Fujii, Tetsuya, Nakamizu, Masaru, Lu, Hailong, Ripmeester, John A. 07 1900 (has links)
The pore saturation of natural gas hydrate in sediments is a key parameter for estimating hydrate resources in a reservoir. For a better understanding of gas hydrate distribution, the experimental study of the pore saturation of methane hydrate in sediments from a hydrate reservoir in the Eastern Nankai Trough have been carried out. In total, eleven samples, comprising sand, silty sand, silt, and representative of the main sediment types identified in the Eastern Nankai trough, were tested. The results obtained clearly indicate a particle size and clay content dependent trend: almost 100% of pores were saturated with methane hydrate in sand when little silt and clay were present, decreasing to ~ 13% in silty sand (sand 54%, silt 41% and clay 5%), and ~ 4% in clayey silt. These results are generally consistent with NMR logging results for high-saturation samples, but somewhat different for samples with medium or low saturation levels.
64

Structure et Origine de la Plaque Caraïbe. Implications Géodynamiques

Leroy, Sylvie 21 December 1995 (has links) (PDF)
La géodynamique du domaine Caraïbe, sa déformation et son évolution sont analysés à partir des données de géologie et de géophysique marine, telles que la bathymétrie, la sismique réflexion et réfraction, la gravimétrie et le magnétisme. Ce travail commence par une étude bibliographique du domaine Caraïbe établissant un état des recherches au début de notre étude. L'instrument géophysique majeur utilisé est la sismique multitrace, et notamment les données de la campagne Casis qui ont été traitées classiquement et plus spécifiquement par migration avant sommation (Leroy et al, 1996). Notre travail s'est divisé en deux parties, la première concerne le domaine Nord Caraïbe et plus particulièrement le fossé Cayman, et la deuxième examine, en détail, la Grande Province Volcanique Caraïbe, sa déformation et sa structure crustale. Dans le fossé Cayman, les deux marges conjuguées sont asymétriques, la marge du Belize est abrupte tandis que la marge Jamaïcaine est large et peu sédimentée. L'ensemble des données a permis de définir les blocs basculés de la croûte continentale, non enfouis sous les sédiments, une transition Continent-Océan constituée par un mont arrondi et par une importante dépression syn-rift, et le domaine océanique où les blocs océaniques sont basculés vers la dorsale. Des failles de détachements et les réflexions du Moho sont imagées grâce à la sismique de haute qualité. Les bordures Nord et Sud du fossé sont formées par des fosses profondes qui constituent des marges transformantes entre les croûtes Jamaïcaine et Cubaine épaisses et la croûte continentale amincie ou océanique. Dans le domaine océanique, une discontinuité majeure a été identifiée à l'axe d'expansion. L'identification des anomalies magnétiques sur l'ensemble du fossé conduit à la datation de la Transition Continent Océan (Lutétien inférieur; 49 Ma), à refermer le bassin et à proposer un modèle d'évolution de la zone Nord Caraïbe par le fonctionnement successif (du Nord au Sud) de failles transformantes senestres qui accommodent le mouvement de la plaque vers l'Est. La dorsale océanique s'est propagée vers le Sud entre les anomalies 6 et 8. A la même époque, au Néogène, la trace fossile de la faille transformante Swan a été réactivée entraînant la formation de structures compressives jusqu'à Hispaniola à l'Est. Une déformation Miocène compressive est observée sur la plaque Caraïbe, formée en majeure partie par un plateau volcanique d'âge Crétacé, et divisée en deux bassins (Colombien à l'Ouest, et Vénézuélien à l'Est). La compression augmente du Sud vers le Nord et les structures compressives sont décalées de manière dextre par des accidents orientés NE-SW. La partie centrale et occidentale de la ride de Beata est formée par des hauts topographiques orientés NS décalés de façon dextre. Le point culminant est situé au Nord, se reliant au massif montagneux de Hispaniola (Bahoruco). La tectonique compressive s'effectue sous une contrainte orientée E-W à NE-SW. Son maximum est situé dans la presqu'île Sud d'Haïti et se traduit par une collision avec le bâti Nord d'Hispaniola. On peut évaluer le raccourcissement à 170 km. Le bassin Caraïbe apparaît formé de deux microplaques et la microplaque Colombienne se déplace plus rapidement vers l'Est que la microplaque Vénézuélienne. Ce mouvement différentiel peut être la conséquence d'un mouvement de convergence plus important à l'Ouest qu'à l'Est des plaques Amériques et d'une influence de la rapide convergence de la plaque Cocos. La Grande Province Magmatique Caraïbe atteint 800 000 km2, dont une partie est accrétée sur le continent par obduction et/ou collision. La taille de la province magmatique est de 2500 km de diamètre. On distingue des petits plateaux séparés par des bassins. L'âge des formations volcaniques s'échelonne depuis l'Albien (110 Ma) jusqu'au Campanien (80 Ma), avec un épisode important à 88 Ma (Coniacien) qui affecte l'ensemble de la province magmatique et nous concluons que le volcanisme n'est pas instantané. Nous avons compilé les données de sismique réfraction et différencié une couche 2 (4.6 et 6 km/s) et une couche 3 (plus de 6 km/s). L'épaississement de la croûte s'effectue au niveau de la couche 3, comme sur le plateau des Kerguelen, par sous-placage. En effet, la couche 2 reste mince aussi bien sur les plateaux (4 km) que dans les bassins (2 km); cette disposition explique les affleurements de gabbros (couche 3) le long de l'escarpement Ouest de la ride de Beata. Nous optons pour une origine Pacifique de la plaque Caraïbe et on note de nombreuses analogies avec les Grandes Provinces Magmatiques du Pacifique Ouest (bassin de Nauru, Ontong Java et bassin de Pigafetta), mais nous rejetons l'hypothèse du panache géant situé dans le Pacifique, et nous rattachons la Grande Province Caraïbe au point chaud des Galápagos.
65

Μελέτη συγκεντρωτικού φωτοβολταϊκού συστήματος V-Trough

Νίνος, Μιχάλης 04 December 2012 (has links)
Η ηλιακή ενέργεια στο σύνολό της είναι πρακτικά ανεξάντλητη, και είναι η κυριότερη μορφή ανανεώσιμης πηγής. Η ηλιακή ακτινοβολία παρέχει ένα τεράστιο ποσό ενέργειας στη Γη. Τα ηλιακά φωτοβολταϊκά στοιχεία, γνωστά ως "φωτοβολταϊκά" ή "Φ/Β", αποτελούν μία προσέγγιση υψηλής τεχνολογίας για την άμεση μετατροπή του ηλιακού φωτός σε ηλεκτρική ενέργεια. Κατα τη διάρκεια αυτής της διπλωματικής εργασίας έγινε μια αναλυτική περιγραφή του τρόπου λειτουργίας τους και ιδιαίτερα υπό συνθήκες χαμηλής συγκέντρωσης. Πιο συγκεκριμένα, στο 1ο Κεφάλαιο γίνεται μια εισαγωγή στις ανανεώσιμες πηγές ενέργειας και ιδιαίτερα στην ηλιακή. Παρουσιάζεται η εξέλιξη των Α.Π.Ε. στον ελλαδικό χώρο και οι αιτίες που έστρεψαν τον άνθρωπο σε νέες μορφές ενέργειας πέραν τον ορυκτών καυσίμων. Στο Κεφάλαιο 2 γίνεται αναφορά στη θεωρία της Ηλιακής Γεωμετρίας που συνδέεται με τις δυο κύριες κινήσεις της Γης, την ημερήσια περιστροφή της και την ετήσια γύρω από τον Ήλιο. Παρουσιάζονται θεωρητικά μοντέλα πρόβλεψης της ηλιακής ακτινοβολίας και σχέσεις υπολογισμού της σε επιφάνειες στο επίπεδο της Γης. Στο Κεφάλαιο 3 παρουσιάζεται μια σύντομη περιγραφή της λειτουργίας των φωτοβολταϊκών κυττάρων και των φυσικών ιδιοτήτων αυτών των ημιαγώγιμων διατάξεων. Επίσης γίνεται λόγος για τις υπάρχουσες τεχνολογίες φωτοβολταϊκών με τα πλεονεκτήματα και τα μειονεκτήματά τους και για διάφορα φαινόμενα που επηρεάζουν τη λειτουργία τους. Το Κεφάλαιο 4 είναι αφιερωμένο στα συγκεντρωτικά συστήματα και σε όλες τις υπάρχουσες γεωμετρίες που χρησιμοποιούνται αυτή τη στιγμή και ιδιαίτερα στη γεωμετρία του V-Trough που χρησιμοποιήθηκε στο πειραματικό σκέλος. Επίσης γίνεται αναφορά για τα συστήματα παρακολούθησης του Ήλιου. Στο Κεφάλαιο 5 παρουσιάζονται διάφορες τεχνολογίες ψύξης που έχουν δημοσιευθεί σε επιστημονικές εργασίες και συνοδεύουν τα συγκεντρωτικά συστήματα, λόγω των υψηλών θερμοκρασιών που επιφέρουν στα κύτταρα. Στο Κεφάλαιο 6 γίνεται αναφορά στο πειραματικό κομμάτι της εργασίας με παρουσίαση των μετρητικών οργάνων και των αποτελεσμάτων των μετρήσεων που έγιναν στο συγκεντρωτικό σύστημα V-Trough, στο σταθερό φωτοβολταϊκό μονοκρυσταλλικού πυριτίου και στο φωτοβολταϊκό πλαίσιο μικρομορφικού πυριτίου (thin film). Στο Κεφάλαιο 7 παρουσιάζονται υπολογιστικές μέθοδοι για την εκτίμηση της ακτινοβολίας και της παραγόμενης ενέργειας από το V-Trough και το σταθερό φωτοβολταϊκό πλαίσιο σε ετήσια βάση. Επίσης παρουσιάζεται μέθοδος υπολογισμού της βέλτιστης κλίσης για κεκλιμένες επιφάνειες και μέθοδος για την αποφυγή σκιάσεων αυτών των επιφανειών. Επίσης γίνεται εξομοίωση φωτοβολταϊκών εγκαταστάσεων με χρήση του προγράμματος PV*SOL. Το Κεφάλαιο 8 περιέχει τα συμπεράσματα ως προς τη χρήση του συγκεντρωτικού συστήματος, τις υπολογιστικές μεθόδους και τα υπόλοιπα θέματα που παρουσιάσθηκαν σε αυτή τη διπλωματική. / The solar energy is practically inexhaustible, and it is the main form of renewable source. The solar radiation provides the Earth with a huge amount of energy. The solar cells, known as photovoltaics, compose an approach of high technology for the direct conversion of light into electricity. During this thesis an analytic description of their operation was made and specifically under low concentration conditions. Particularly, in the 1st Chapter is made an introduction to the renewable sources and specifically in solar. Showing the evolution of R.E.S. in Greece and the reasons that turned humans into new forms of energy than the fossil fuels. Chapter 2 refers to the theory of solar geometry associated with the two main movements of Earth, the daily rotation and the yearly around the Sun. Presented theoretical models, predicting and calculating the solar radiation on surfaces at the Earth’s level. Chapter 3 presents a brief description of the operation of photovoltaic cells and the physical properties of these semiconductor devices. Also refers to the existing photovoltaic technologies with their advantages and disadvantages and to various effects that influence their operation. Chapter 4 is devoted to the concentrating systems and all existing geometries used at this time and especially the V-Trough geometry that used in the experiments. A reference also is made to solar tracking systems. Chapter 5 presents various cooling technologies that have been published in scientific papers and accompanying concentrating systems due to high temperatures that cause to cells. Chapter 6 refers to the experimental part of this thesis with presentation of the experimental devices and the results of measurements made in the concentrating system V-Trough, the stable monocrystilline silicon photovoltaic panel and the micromorph silicon thin film panel. Chapter 7 presents computational methods for the estimation of radiation and the energy produced by the V-Trough and stable photovoltaic panel on an annual basis. Also presents method of calculating the optimum tilt for inclined surfaces and a method of avoiding the shading on this surfaces. Also a simulation of photovoltaic plants is made by the PV*SOL software. Chapter 8 contains the general conclusions related with the experimental results, the theoretical calculations and all the other issues that presented in this thesis.
66

La marge Nord du Fossé Basque à l'Albien : architecture sédimentaire et diapirisme dans un contexte décrochant (Pays Basque, Espagne) / The Albian northern margin of the Basque Trough : sedimentary architecture and diapirism in a strike-slip tectonic setting (Basque Country, Spain)

Poprawski, Yohann 27 January 2012 (has links)
L'objectif initial de cette thèse consistait à fournir un analogue de terrain de réservoirs pétroliers avec un modèle 3D des structures et de l'architecture des sédiments développés sur la bordure d'un basin étroit et confiné. La zone d'étude, située entre Bakio et Plenzia (Pays Basque, Espagne), appartient au fossé Basque, souvent interprété comme un basin en pull-apart. Nous avons focalisé ce travail sur le diapir de Bakio, sur les modalités de la montée du sel, sa chronologie et sur l'impact de la tectonique salifère sur sédimentation et la déformation des sédiments environnants. Un éventail sédimentaire composé de dépôts albiens, avec un amincissement vers le diapir montre la monté synsédimentaire du sel. Nous démontré l'existence d'une première phase de montée du sel réactive puis une seconde phase passive. La phase réactive est expliquée par l'extension régionale. Durand le stade passive, des séquences halokinetiques, qui résultent de variations entre la monté du sel et le taux de sédimentation, ont été formées. Nos données montre qu'une grande partie de la déformation est due à la rotation des flancs du diapir et non à un cisaillement significatif induit par la montée su sel. Nous avons aussi concentré ce travail sur les structures albiennes de notre zone d'étude. La comparaison avec l'ensemble du Bassin Basco Cantabrien montre deux stades d'activation des failles. De l'Aptien à l'Albien moyen, les nombreuses failles orientées NE-SO, largement distribuées,contrôlaient les plates formes urgoniennes et les fossés marneux associés. Quelques failles majeures héritées, orientées NO-SE contrôlaient aussi les dépocentres surtout dans la partie centrale du Basin Basco-Cantabrien. Ce premier stage est interprété comme le résultat d'un extension NO-SE. De l'Albien moyen à supérieur, la déformation était localisée essentiellement le long de la faille Guernika-Elgoibar, orientée NO-SE, qui contrôle un bassin asymétriques, étroit et allongé remplis par les Flyschs Noirs. Durant le second stage, les dépocentres du Flysch Noir sont interprétés comme des bassins en transtension et non en pull-apart, car une seule faille majeure contrôlait ces basins asymétriques. / The initial purpose of this thesis was to provide a field analogue for petroleum reservoirs with a 3D model of the main structures and of the architecture of deposits developed on the border of a narrow and confined basin. The study area, located between Bakio and Plenzia (Basque Country, Spain), belongs to the Basque Trough, commonly interpreted as a pull-apart basin. We focused on the Bakio diapir, which allows a discussion of the modalities of salt rising, its chronology and of the impacts of salt on the overburden deformation and on sedimentation. A well exposed wedge-shaped structure composed of Albian deposits, with thinning toward the diapir documents synsedimentary salt rising. We showed that the diapir rose firstly as a reactive diapir in response to regional extension and then as a passive diapir. During the passive stage, halokinetic sequences developed, induced by variations of the ratio between net salt rising and net sedimentation rate. All our data from the Bakio diapir show that an important part of deformation is related to diapir flank rotation and not to significant shear associated with salt rising. We also focused on the Albian structural geology in our study area. The comparison of the local Albian fault system with faults from the whole Basque-Cantabrian Basin emphasizes two stages of faults activity. From Aptian to Early-Middle Albian, widely distributed NE-SW striking faults controlled the development of the Urgonian platforms and associated marly troughs. Some major inherited NW-SE striking faults also controlled the localization of depocenters, especially in the central part of the Basque-Cantabrian Basin. The first stage is assumed to result of a NW-SE extension. From Middle to Late Albian, the deformation localized mainly along the Gernika-Elgoibar fault, striking NW-SE, and controlled the formation of a narrow and elongated asymmetric basin developed, filled by Black Flysch units. During this second stage, Black Flysch depocenter are interpreted to form in transtensional setting and cannot be interpreted as pull-apart basins, as only one major fault controlled asymmetric basins.
67

Concentrating Collector for Torsång District Heating System

Filatov, Artem January 2018 (has links)
In this thesis report for Dalarna University in Borlange and Absolicon company the study of a possibility to add an array of concentrating solar collectors to a Torsång district heating system was done. The whole idea of this work was to make a simulation of this kind of system, trying to get 15-20% of solar fraction, and make an economical evaluation. At the same time, another goal was to make two comparisons: between concentrating and flat-plate collector in the same system, and between two tools for collector analysis – Polysun and Absolicon tool, based on TRNSYS, which was designed to estimate the output of the collector for a certain temperature, without any load. During the study, the analysis of the simulating tools was made and the combination of those two tools was used. Using long iteration cycles, involving changing the field layout, number of collectors and distance between collector rows in flat-plate collector case, both types of collectors were analyzed. The method of the analysis was to get an equal output of the field and see the differences, which appear while using different collector types.
68

(O)motiverad Invandrarpolitik : en studie om motiven att frångå invandrarpolitik och införa integrationspolitik

Ekholm, Erika January 2007 (has links)
An effective Integration policy is important in Sweden while our government has decided and committed to be a country where everybody will be given the same opportunities. There is a greater awareness in today’s society of integration policy goals such as equal rights, responsibilities and opportunities for all. In a number of areas, however, the disparities between immigrants and Swedish-born citizens are still too large. The Swedish Riksdag decided on integration policy in 1997. The main task for this thesis will be to examine the motive behind the Government's decision to revoke immigrations policy and introduce integration policy. This task will be completed with two questions at issue; • Which were the obvious pronounced and underlying, extern- and intern sectorial motives and which immigrant policies could be identified during the three periods; 1, 2 and 3? • In what way have the extern- and intern sectorial motives, that where expressed in 1997, affected the douting in 2006 years integrationspolicy? The questions will be examined by using Lindbloms muddling through theory and Dahlströms “eigth faces of immigration politics” and for identifying motives a model inspired by Hadenius will be used. The empirical material has brought forward that the decision to introduce integrationpolicy was based on the central motive that earlier immigration policy produced assimilationpolitics. Which futher on caused the “perverse effect” – segregationpolitics. The adjustments have been clarifying of words sooner than improvement of concrete measures. The Swedish government has applied seven different immigrationpolitics during the periods 1, 2 and 3. Becides Dahlströms “eight faces of immigration politics” two more have been identified; “demanding politics and condition politics”. Seven of the ten different types have been noticed; assimilation-, segregation-, diversity-, demanding, condition-, residual-, universial politics. The motives that where observed during period 2 didn´t improve the conditions for the immigrant which were discriminated in society especially on the labourmarket. The motives from period 2 have therefore affected the motives for period 3. The recently appointed government will during it´s runningperiod try to leave the muddling through theory by the motives in creating conditions for a “self earned living” and participation. By doing this the esscense of diversity and integration policy will hopefully be reached.
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CHARACTERIZATIONS OF LINEAR GROUND MOTION SITE RESPONSE IN THE NEW MADRID AND WABASH VALLEY SEISMIC ZONES AND SEISMICITY IN THE NORTHERN EASTERN TENNESSEE SEISMIC ZONE AND ROME TROUGH, EASTERN KENTUCKY

Carpenter, Nicholas von Seth 01 January 2019 (has links)
The central and eastern United States is subject to seismic hazards from both natural and induced earthquakes, as evidenced by the 1811-1812 New Madrid earthquake sequence, consisting of at least three magnitude 7 and greater earthquakes, and by four magnitude 5 and greater induced earthquakes in Oklahoma since 2011. To mitigate seismic hazards, both earthquake sources and their effects need to be characterized. Ground motion site response can cause additional damage to susceptible infrastructure and buildings. Recent studies indicate that Vs30, one of the primary site-response predictors used in current engineering practice, is not reliable. To investigate site response in the New Madrid Seismic Zone, ratios of surface-to-bedrock amplitude spectra, TFT, from S-wave recordings at the two deep vertical seismic arrays in the sediment-filled upper Mississippi Embayment (i.e., VSAP and CUSSO) were calculated. The mean TFT curves were compared with theoretical transfer functions; the results were comparable, indicating that TFT estimates of the empirical, linear SH-wave site responses at these sites. The suitability of surface S-wave horizontal-to-vertical spectral ratios, H/V, for estimating the empirical site transfer function was also evaluated. The results indicate that mean S-wave H/V curves are similar to TFT at low frequencies (less than the fifth natural frequencies) at both CUSSO and VSAP. SH-wave fundamental frequency, f0, and fundamental-mode amplification, A0, were evaluated as alternatives to the Vs30 proxy to estimate primary linear site-response characteristics at VSAP, CUSSO, and nine other seismic stations in the CEUS. In addition, calculated f0 and A0 were compared with the first peaks of S-wave H/V spectral ratios. The f0 and A0 were found to approximate the 1-D linear, viscoelastic, fundamental-mode responses at most stations. Also, S-wave H/V from weak-motion earthquakes can be used to measure f0. However, S-wave H/V does not reliably estimate A0 in the project area. S-wave H/V observations reveal site response within the frequency band of engineering interest from deeper, unmodeled geological structures. Because damaging or felt earthquakes induced by hydraulic fracturing and wastewater disposal have occurred in the CEUS, characterizing background seismicity prior to new large-scale subsurface fluid injection is important to identify cases of and the potential for induced seismicity. The Rogersville Shale in the Rome Trough of eastern Kentucky is being tested for unconventional oil and gas potential; production of this shale requires hydraulic fracturing, which has been linked to induced seismicity elsewhere in the CEUS. To characterize natural seismicity and to monitor induced seismicity during testing, a temporary seismic network was deployed in the Rome Trough near the locations of new, Rogersville Shale oil and gas test wells. Using the real-time recordings of this network and those of other regional seismic stations, three years of local seismicity were cataloged. Only three earthquakes occurred in the Rome Trough of eastern Kentucky, none of which was associated with the deep Rogersville Shale test wells that were stimulated during the time the network was in operation.
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RC Trough Bridges: A Parametric Study using FEM and an Analysis of their Current State

Åkergren, David January 2021 (has links)
There are approximately 4000 railway bridges in Sweden managed by the Swedish Administration of Transport (Trafikverket), of which a common construction type is the reinforced concrete (RC) trough bridge, which is a structure that consists of a slab carried by two longitudinal main beams which transfer loads towards the supports. A substantial amount of the RC trough bridge population is approaching the end of their service lives which consequently implies that the replacement of some of these bridges can be expected in the near future. Extending their service lives can yield positive effects from a financial- as well as an environmental perspective, and therefore it is highly beneficial to evaluate their capacities as realistically as possible. One factor that may help improve accuracy during the determination of their capacities is an evaluation of how it is affected by the location of the railway track on the bridge.  In current design codes defined by Trafikverket, consideration is taken to horizontal track displacement for a minimum displacement of 0.1 m if there doesn’t exist data suggesting that a larger displacement is prevalent on the bridge. However, Trafikverket has received data which suggest that a considerable number of bridges could experience load eccentricities which exceed the standard minimum value. This raises the question whether or not 0.1m is the most optimal limit value for load eccentricity on railway bridges. For RC trough bridges, a larger load eccentricity may result in one main beam carrying a larger portion of the load which will decrease the axle load which the bridge can carry. It is therefore important to evaluate the influence of larger horizontal displacements than what is currently is considered as a preventive action.   In addition, several studies on Swedish concrete bridges constructed during the 20th century have pointed to a significant increase in concrete compressive- and tensile strength over time. This suggests that it is possible that a considerable amount of RC trough bridges have a higher capacity than what was originally intended, and further research is required in order to understand the behaviour of these bridges when key material parameters are altered.        There are three main tasks which this master thesis seeks to complete. The first part is a detailed analysis of a database named BaTMan (Bridge and Tunnel Management) that belongs to Trafikverket. In this analysis parameters such as span length, age, material type and damages for every identified railway bridge is extracted and further processed in Microsoft Excel in order to gain a clear overview of the RC trough bridge population. The second task regards the development of a non-linear finite element model of a typical RC trough bridge named Lautajokki. The model is analysed using ATENA Science and its behaviour is verified against test results obtained during a full-scale test of the bridge performed by Paulsson et al. (1996). The last task is to use the devolved model to perform a parametric study where the effects of changes in load eccentricity, compressive strength as well as tensile strength is studied.

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