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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.
31

Ett gemensamt verktyg för tillverkning av telekrigsbibliotek?

Träff, Magnus January 2015 (has links)
Försvarsmaktens telekrigsstödenhet (TKSE) har uppgiften att försörja Försvarsmaktens Varning- och motverkanssystem (VMS) med telekrigsbibliotek. Telekrigsbibliotek krävs för att VMS, skall fungera. Med ett gemensamt verktyg för flera VMS, kan den militära nyttan höjas. Genom att möjliggöra att flera system kan samverka vid produktionen, kan flera svaga hypoteser kan blir starkare. Dock kommer detta inte att vara enkelt på grund av den finansiering modell som Försvarsmakten arbetar med. Den som ansvarar för plattformutrustning och producerande enhet har inte alltid möjlighet att nå den optimala lösningen på grund av andra hänsynstaganden.
32

Ore Petrology and Alteration of the West Ansil Volcanic-hosted Massive Sulphide Deposit of the Noranda Mining Camp, Rouyn-Noranda, Quebec

Boucher, Stéphanie January 2011 (has links)
The West Ansil deposit was the first Cu discovery in 25 years in the Noranda Central Camp. It has a combined indicated and inferred resource of ~1.2 Mt. Grades for the indicated resource are 3.4% Cu, 0.4% Zn, 1.4 g/t Au and 9.2 g/t Ag. The bulk of the resource is located in three massive sulphide lenses (Upper, Middle and Lower) that are entirely within the Rusty Ridge Formation above the Lewis exhalite. The mineralization in all three ore lenses consists of massive pyrrhotite + chalcopyrite + magnetite. Semi-massive sphalerite is restricted to the upper and lower parts of the Middle lens. Massive magnetite occurs at the center of the Upper and Middle lenses, where it replaces massive pyrrhotite. A striking feature of West Ansil is the presence of abundant colloform and nodular pyrite (+marcasite) in the massive sulphides. Late-stage replacement of massive pyrrhotite by colloform pyrite and marcasite, occurs mostly along the upper and lower contacts of the lenses.
33

Mineralization and Alteration of the Late Triassic Glacier Creek Cu-Zn VMS Deposit, Palmer Project, Alexander Terrane, Southeast Alaska

Steeves, Nathan January 2013 (has links)
The Glacier Creek volcanogenic massive sulfide (VMS) deposit is hosted within Late Triassic, oceanic back-arc or intra-arc, rift-related, bimodal volcanic rocks (Hyd or Tats Group) of the allochthonous Alexander terrane known as the Alexander Triassic Metallogenic Belt (ATMB). The deposit presently consists of four tabular massive sulfide lenses with a resource of 4.75 Mt. at 1.84% Cu, 4.57% Zn, 0.15% Pb, 0.28 g/t Au and 29.07 g/t Ag. A deposit-scale thrust fault offsets stratigraphy along the axial surface of a deposit-scale anticline. The massive sulfide lenses are barite-rich and are divided into 6 main ore-types based on mineral assemblages. There is a large range of sphalerite compositions, with low-Fe sphalerite dominant throughout the lenses and high-Fe sphalerite at the top and bottom of the lenses in pyrrhotite-rich zones. Lenses contain anomalous Sb, Hg and Tl. Gangue minerals include barite, quartz, barian-muscovite, calcite, albite, highly subordinate chlorite and locally hyalophane and celsian. Overlying massive sulfide is a tuffaceous hydrothermal sediment with anomalous REE patterns and local hyalophane. The general footwall to all four lenses is a thick unit of coherent to volcaniclastic feldspar-phyric basalt containing extensive lateral alteration. Four alteration facies are recognized based on mineral assemblages. Mass balance calculations for the footwall indicate general gains of S, Fe, Si and K with coincident loss of Ca, Na and Mg, along with trace element gains of Tl, Sb, Hg, Ba, Zn, Cu, As and loss of Sr with increased alteration intensity. Short wavelength infrared (SWIR) spectroscopy shows a general decrease in Na, K and Al content of muscovite and increase of Fe+Mg and Ba content towards ore. Integrated petrographic, mineral, chemical and sulfur-isotope data suggest a transition during deposit formation, from high-temperature, acidic, reduced hydrothermal fluids mixing with oxidized, SO4-rich seawater, to later cooler, low fO2-fS2 conditions of formation and a lack of SO4 in seawater.
34

Geology of the Kidd Creek Deep Orebodies - Mine D, Western Abitibi Subprovince, Canada

Gemmell, Thomas P. January 2013 (has links)
The giant Kidd Creek Mine is an Archean Cu-Zn-Ag deposit in the Abitibi Greenstone belt, located in the Superior Province of Canada and is one of the largest known base metal massive sulfide mines in the world with a tonnage of 170.7 Mt (Past production, Resource and Reserve). The massive sulfides in Mine D comprise a number of ore lenses that are interpreted to be the downplunge continuation of the Central orebody from the upper mine. These are referred to as the West, Main, and South lenses. The massive sulfides overlie a silicified rhyolitic unit at the top of a mixed assemblage of rhyolite flows, volcaniclastic sediments and ultramafic flows. The sheared nature of the fragmental units in the hanging wall of the deposit, at depth, illustrates the greater deformation that has occurred than in the upper mine. Metal zonation and the distribution of Cu stringer mineralization suggest that the West and Main lenses may be part of a single massive sulfide body (Main orebody) that has been structurally dismembered. The South Lens is a detached body, separated by late faults. The large Cu stringer zone beneath the West and Main lenses has a thickness of up to 150 metres, and is much broader and structurally remobilized in Mine D partially due to a newly identified series of vertically trending offset faults, that extends along the entire length of the massive sulfide bodies. A number of features of the North, Central and South orebodies in the upper part of the mine (e.g., Se-rich halo around Cu-rich zones) have been recognized in Mine D and provide an important framework for correlating the deep orebodies with the upper levels of the mine. Drilling below the current mine levels indicates that the massive sulfide and Cu stringer zones continue below 10,200 feet (3109 m) and highlight the remarkable continuity of the deposit downplunge with no end in sight. Two main ore suites have been recognized in the upper part of the mine and in Mine D: a low-temperature, polymetallic assemblage of Zn, Ag, Pb, Cd, Sn, Sb, As, Hg, ±Tl, ±W, and a higher-temperature suite of Cu, Co, As, Bi, Se, In, ±Ni. More than 25 different ore minerals and ore-related gangue minerals are present, including Co-As-sulfides, Cu-Sn-sulfides, Ag-minerals, and selenides. The massive ores consist mainly of pyrite, pyrrhotite, sphalerite, magnetite and chalcopyrite, together with minor galena, tetrahedrite, arsenopyrite, and native silver with a quartz and siderite gangue. Despite the high Ag content of the ores, the majority of the massive sulfides are remarkably Au poor except for a local gold zone that has been recognized in the deep mine in association with high-temperature mineralization. The trace elements in the ores exhibit strong zonation and diverse mineralogy. Spectacular albite porphyroblasts, up to 1 cm in size occur in the most Cu-rich ores of Mine D which are coincident with the peak of regional metamorphism and likely represent higher metamorphic or hydrothermal temperatures. Overall the orebodies have remained remarkably similar downplunge. However, unlike the upper part of the mine, pyrrhotite is dominantly hexagonal, only tetrahedrite was observed as the dominant sulfosalt, and magnetite occurs as both blebby porphyroblasts and as abundant intergrowths with sphalerite-chalcopyrite ores and siderite. These characteristics suggest that the deep mine has been subjected to higher metamorphic temperatures, possibly related to depth of burial, and that the original hydrothermal fluids may of had a lower H2S/CO2 and/or higher temperatures.
35

Návrh soupravy pro vytvoření zásobovacího místa elektrickou energií vytvořenou z obnovitelných zdrojů / Design of a kit for the creation of a supply point for electricity generated from renewable sources

Fridrich, Jiří January 2021 (has links)
This project deals with the design and realisation of a set that will work as a power supply point with electricity generated from renewable energy sources. The theoretical part deals with information about renewable energy sources and energy storage options. In the practical part, a mobile kit for powering variable message traffic signs is designed. It uses photovoltaic panels and stores energy in a lead-acid battery. A methanol fuel cell is used for backup power. The device is adapted for use in road traffic and meets the requirements of the relevant authorities. To verify the stability of the structure, there were performed static calculations, which proved the ability of the device to withstand wind stress. Part of the work was to draw a complete production documentation, which was used to create a test sample. Long-term measurements of energy flows in the system were performed on that sample. These measurements confirmed the ability of the device to operate autonomously and the possibility of using it for the required purpose.
36

Assessment Of The Safety Benefits Of Vms And Vsl Using The Ucf Driving Simulator

Dos Santos, Cristina 01 January 2007 (has links)
Researchers at the University of Central Florida (UCF) have been working during the past few years on different strategies to improve freeway safety in real-time. An ongoing research at UCF has investigated crash patterns that occurred on a stretch of Interstate-4 located in Orlando, FL and created statistical models to predict in real-time the likelihood of a crash in terms of time and space. The models were then tested using PARAMICS micro-simulation and different strategies that would reduce the risk of crashes were suggested. One of the main recommended strategies was the use of Variable Speed Limits (VSL) which intervenes by reducing the speed upstream the segment of high risk and increasing the speed downstream. The purpose of this study is to examine the recommendations reached by the micro-simulation using the UCF driving simulator. Drivers' speed behavior in response to changes in speed limits and different information messages are observed. Different scenarios that represent the recommendations from the earlier micro-simulation study and three different messages displayed using Variable Message Signs (VMS) as an added measure to advice drivers about changes in the speed limit were created. In addition, abrupt and gradual changes in speed were tested against the scenarios that maintained the speed limit constant or did include a VSL or VMS in the scenarios' design (base case). Dynamic congestion was also added to the scenarios' design to observe drivers' reactions and speed reductions once drivers approached congestion. A total of 85 subjects were recruited. Gender and age were the controlling variables for the subjects' recruitment. Each of the subjects drove 3 out of a total of 24 scenarios. In addition, a survey was conducted and involved hypothetical questions, including knowledge about VMS and VSL, and questions about their driving behavior. The survey data were useful in identifying the subjects' compliance with the speed limit and VSL/VMS acceptance. Two statistical analytical techniques were performed on the data that were collected from the simulator: ANOVA and PROC MIXED. The ANOVA test was used to investigate if the differences in speed and reaction distances between subjects were statistically significant for each sign compared to the base case. The PROC MIXED analysis was used to investigate the differences of all scenarios (24x24) based on the spot speed data collected for each driver. It was found from the analyses that drivers follow better the message displayed on VMS that informs them that the speed is changing, whether it is or not, strictly enforced as opposed to providing the reason for change or no information. Moreover, an abrupt change in speed produced immediate results; however both abrupt and gradual changes in speed produced the same reduction in speed at the target zone. It was also noticed that most drivers usually drive 5 mph above the speed limit, even though in the survey analysis the majority of them stated that they drive in compliance with the speed limit or with the flow of traffic. This means that if a modest speed reduction of 5 mph is requested they will ignore it, but if a 10 mph reduction is recommended they will reduce the speed by at least 5 mph. Consequently, it was noticed that drivers arrived at the congestion zone with a slower speed than the base speed limit due to the combination of VMS and VSL signage. By having drivers approaching congestion with a slower speed, potential rear-end crashes could be avoided. Comparing the two genders indicated that females are more likely to follow the VMS's recommendations to reduce the speed. Also females in general drive above the speed limit between 2 mph and 3 mph, while males drive above the speed limit between 5 mph and 8 mph. From the analysis of the age factor, it was concluded that drivers from the 16-19 age group drive faster and drivers from the 45 and above age group drive slower, than the drivers from the other groups. In general, all drivers reduced and/or increased their speed accordingly when a VMS and/or VSL was present in the scenario advising for this change in the speed limit. The investigations conducted for this thesis proved that the recommendations suggested previously based on the crash risk model and micro-simulation (Abdel-Aty et al., 2006) aid drivers in reducing their speed before they approach a segment of high risk and by doing so reduce the likelihood of a crash. Finally, the real-time safety benefits of VMS and VSL should be continuously evaluated in future studies.
37

U-Pb age constraints on the host rocks of the Barsele Norra Volcanogenic Massive Sulphide deposit, northern Sweden

Sandlund, Maria January 2021 (has links)
The Barsele area is located in the "Gold Line", southwest of the volcanogenic massive sulphide (VMS) Skellefte district which hosts more than 85 known VMS-deposits where some are gold-bearing. The Barsele area consists of the Central, Avan and Skiråsen intrusion hosted gold deposits, the Norra gold-bearing VMS-deposit and the Risberget zone. This study includes a geochronological study of two coherent volcanic rocks from the Norra zone using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry and Scanning Electron Microscope images of zircons and also includes petrographic microscopy of thin sections and lithogeochemical data used in classification diagrams.  This study presents two new LA-ICP-MS zircon U-Pb ages for VMS-hosting volcanic rocks from the Barsele area: o   1956.8 ± 6.47 Ma (n: 17, MSWD: 0.99), sample A from a hydrothermally altered volcanic rock  o   1952.2 ± 14.5 Ma (n: 6, MSWD: 1.1), sample B from a rhyolite-dacite  The new U-Pb age constraints presented in this study indicate that the volcanic rocks of the Norra zone are older than the volcanic rocks in the Skellefte Group. The results presented in this report together with the earlier dated c. 1.96 Ga metadacite suggests that the volcanic rocks of the Barsele area are located at a lower chronostratigraphic level than the Skellefte Group, i.e., at the chronostratigraphically lower Bothnian Supergroup. Additionally, the results presented here conclude that two VMS-events can be delineated by geochronological data which further opens up for the question if the Barsele area belong to an older arc system (e.g., the Knaften arc) or were part of an arc system evolving continuously between 1.95-1.88 Ga (e.g., the Knaften-Skellefte arc). / Barsele, Västerbottens län, norra Sverige, ligger i ett område som kallas för Guld linjen och är beläget sydväst om Skelleftefältet där mer än 85 kända förekomster av massiva sulfidmalmer (VMS), vissa guldförande, förekommer. Barseleområdet är uppdelat i Central, Avan och Skiråsen zonen, Norra zonen och Risberget zonen där Norra zonen är en guldförande VMS-fyndighet. Denna studie inkluderar en geokronologisk studie av zirkoner från två vulkaniter från Norra zonen som har analyserats med Laser Ablation Inductively Coupled Plasma Mass Spectrometry och avbildats med svepelektronmikroskop samt petrografisk studie av två tunnslip och klassificeringsdiagram baserade på litogeokemisk data. Denna studie presenterar två nya LA-ICP-MS zirkon U-Pb åldrar för VMS-förande vulkaniter i  Barseleområdet:  o   1956.8 ± 6.47 Ma (n: 17, MSWD: 0.99), prov A från en hydrotermalt omvandlad vulkanisk bergart o   1952.2 ± 14.5 Ma (n: 6, MSWD: 1.1), prov B från en ryolit-dacit De två nya  U-Pb zirkon åldersbestämningarna som presenteras i denna studie indikerar att de vulkaniska bergarterna i Norra zonen är äldre än de vulkaniska bergarterna som tillhör Skelleftegruppen. Vidare antyder de presenterade åldrarna i denna studie tillsammans med den tidigare genomförda dateringen av en metadacit (cirka 1.96 Ga) på att de vulkaniska bergarterna i Barseleområdet kan tillhöra suprakrustala bergarter tillhörande Bottniska bassängen. Barseleområdet föreslås därför förekomma vid en lägre kronostratigrafisk nivå jämfört med Skelleftegruppen, det vill säga vid samma kronostratigrafisk nivå som Bottniska Supergruppen. Utifrån de resultat som presenteras här kan slutsatsen att två VMS-områden kan avgränsas av geokronologiska data som ytterligare öppnar för frågan om Barsele-området tillhör ett äldre bågsystem (t.ex. Knaften-bågen) eller var en del av ett bågsystem som utvecklades mellan 1.95-1.88 Ga (t.ex. Knaften-Skelleftebågen).
38

Simulation numérique d'écoulements autour de corps non profilés par des modèles de turbulence hybrides et un schéma multirate / Numerical simulation of flows around bluff bodies with hybrid models and a multirate scheme

Itam, Emmanuelle 30 November 2017 (has links)
Ce travail est une contribution à la simulation numérique d'écoulements turbulents autour de corps non profilés. Après avoir précisé les ingrédients numériques et les modèles de turbulence utilisés dans nos simulations, nous présentons une étude sur l'évaluation des effets de la procédure dynamique des modèles de sous-maille dans un modèle VMS-LES et une approche hybride RANS/VMS-LES. Des problèmes d'écoulements autour d'un cylindre seul et en tandem sont considérés. Nous étudions ensuite le comportement de modèles de turbulence hybrides pour la simulation d'écoulements en régime sous-critique autour d'un cylindre circulaire. Le calcul de l'écoulement autour d'un cylindre de section rectangulaire par l'approche VMS-LES est aussi présenté. Enfin, dans une dernière partie, après avoir fait une revue des travaux importants sur les schémas d'avancement en temps multirate, nous proposons une nouvelle approche explicite multirate par agglomération de volumes finis que nous appliquons à des calculs d'écoulements turbulents complexes en utilisant un modèle de turbulence hybride. / This work is a contribution to the numerical simulation of turbulent flows around bluff bodies. After specifying the numerical ingredients and the turbulence models used in our simulations, we present a study on the impact of the dynamic sub-grid scale modeling in VMS-LES model and a RANS/VMS-LES hybrid turbulence approach. Simulations of flows around a cylinder and a tandem are performed. Next, we assess the behaviour of some hybrid turbulence models for the simulation of flows around a circular cylinder in the subcritical regime. The computation of the flow around a rectangular cylinder with the VMS-LES approach is also presented. At last, after a review of some important works on multirate time advancing schemes, we propose a new volume-agglomeration explicit multirate approach that is applied to the computation of complex turbulent flows by a hybrid turbulence model.
39

VMS data analyses and modeling for the monitoring and surveillance of Indonesian fisheries / Analyse et modélisation des données VMS pour le suivi et la surveillance des pêches indonésiennes

Marzuki, Marza Ihsan 27 March 2017 (has links)
Le suivi, le contrôle et la surveillance (MCS) des pêches marines sont des problèmes essentiels pour la gestion durable des ressources halieutiques. Dans cette thèse, nous étudions le suivi spatial des activités des navires de pêche en utilisant les données de trajectoire du système de surveillance des navires (VMS) dans le cadre du projet INDESO (2013-2017). Notre objectif général est de développer une chaîne de traitement des données VMS afin de: i) effectuer un suivi de l'effort de pêche des flottilles de palangriers indonésiens, ii) détecter les activités de pêche illégales et évaluer leur importance. L'approche proposée repose sur des modèles de mélange gaussien (GMM) et les modèles de Markov cachés (HMM), en vue d'identifier les comportements élémentaires des navires de pêche, tels que les voyages, la recherche et les activités de pêche, dans un cadre non supervisé. Nous considérons différentes paramétrisations de ces modèles avec une étude particulière des palangriers indonésiens, pour lesquels nous pouvons bénéficier de données d'observateurs embarqués afin de procéder à une évaluation quantitative des modèles proposés et testés.Nous exploitons ensuite ces modèles statistiques pour deux objectifs différents: a) la discrimination des différents flottilles de pêche à partir des trajectoires des navires de pêche et l'application à la détection et à l'évaluation des activités de pêche illégale, b) l'évaluation d'un effort de pêche spatialisé à partir des données VMS. Nous obtenons de très bons taux de reconnaissance (environ 97%) pour la première tâche et nos expériences soutiennent le potentiel d'une exploration opérationnelle de l'approche proposée. En raison du nombre limité de données d'observateurs embarqués, seules des analyses préliminaires on pu être effectuées pour l'estimation de l'effort de pêche à partir des données VMS. Au-delà des développements méthodologiques potentiels, cette thèse met l'accent sur l'importance de la qualité de données d'observation en mer représentatives pour développer davantage l'exploitation des données VMS tant pour la recherche que pour les questions opérationnelles. / Monitoring, control and surveillance (MCS) of marine fisheries are critical issues for the sustainable management of marine fisheries. In this thesis we investigate the space-based monitoring of fishing vessel activities using Vessel Monitoring System (VMS) trajectory data in the context of INDESO project (2013-2017). Our general objective is to develop a processing chain of VMS data in order to: i) perform a follow-up of the fishing effort of the Indonesian longline fleets, ii) detect illegal fishing activities and assess their importance. The proposed approach relies on classical latent class models, namely Gaussian Mixture Models (GMM) and Hidden Markov Models (HMM), with a view to identifying elementary fishing vessel behaviors, such as travelling, searching and fishing activities, in a unsupervised framework. Following state-of-the-art approaches, we consider different parameterizations of these models with a specific focus on Indonesian longliners, for which we can benefit from at-sea observers¿ data to proceed to a quantitative evaluation. We then exploit these statistical models for two different objectives: a) the discrimination of different fishing fleets from fishing vessel trajectories and the application to the detection and assessment of illegal fishing activities, b) the assessment of a spatialized fishing effort from VMS data. We report good recognition rate (about 97%) for the former task and our experiments support the potential for an operational exploration of the proposed approach. Due to limited at-sea observers¿ data, only preliminary analyses could be carried out for the proposed VMS-derived fishing effort. Beyond potential methodological developments, this thesis emphasizes the importance of high-quality and representative at-sea observer data for further developing the exploitation of VMS data both for research and operational issues.
40

Projection based Variational Multiscale Methods for Incompressible Navier-Stokes Equations to Model Turbulent Flows in Time-dependent Domains

Pal, Birupaksha January 2017 (has links) (PDF)
Numerical solution of differential equations having multitude of scales in the solution field is one of the most challenging research areas, but highly demanded in scientific and industrial applications. One of the natural approaches for handling such problems is to separate the scales and approximate the solution of the segregated scales with appropriate numerical method. Variational multiscale method (VMS) is a predominant method in the paradigm of scale separation schemes. In our work we have used the VMS technique to develop a numerical scheme for computations of turbulent flows in time-dependent domains. VMS allows separation of the entire range of scales in the flow field into two or three groups, thereby enabling a different numerical treatment for the different groups. In the context of computational fluid dynamics(CFD), VMS is a significant new improvement over the classical large eddy simulation (LES). VMS does away with the commutation errors arising due to filtering in LES. Further, in a three-scale VMS approach the model for the subgrid scale can be contained to only a part of the resolved scales instead of effecting the entire range of resolved scales. The projection based VMS scheme that we have developed gives a robust and efficient method for solving problems of turbulent fluid flows in deforming domains, governed by incompressible Navier {Stokes equations. In addition to the existing challenges due to turbulence, the computational complexity of the problem increases further when the considered domain is time-dependent. In this work, we have used an arbitrary Lagrangian-Eulerian (ALE) based VMS scheme to account for the domain deformation. In the proposed scheme, the large scales are represented by an additional tensor valued space. The resolved large and small scales are computed in a single unified equation, and the effect of unresolved scales is confined only to the resolved small scales, by using a projection operator. The popular Smagorinsky eddy viscosity model is used to approximate the effects of unresolved scales. The used ALE approach consists of an elastic mesh update technique. Moreover, a computationally efficient scheme is obtained by the choice of orthogonal finite element basis function for the resolved large scales, which allows to reformulate the ALE-VMS system matrix into the standard form of the NSE system matrix. Thus, any existing Navier{Stokes solver can be utilized for this scheme, with modifications. Further, the stability and error estimates of the scheme using a linear model of the NSE are also derived. Finally, the proposed scheme has been validated by a number of numerical examples over a wide range of problems.

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