Dissertations / Theses: 'Glider analysis' – Grafiati (2024)

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Thesis (Master of Engineering in Mechanical Engineering)--Cape Peninsula University of Technology, 2018.
Underwater glider wings are the lifting surfaces of unmanned underwater vehicles UUVs depending on the chosen aerofoil sections. The efficiency as well as the performance of an underwater glider mostly depends on the hydrodynamic characteristics such as lift, drag, lift to drag ratio, etc of the wings. Among other factors, the geometric properties of the glider wing are also crucial to underwater glider performance. This study presents an opportunity for the numerical investigation to improve the hydrodynamic performance by incorporating curvature at the trailing edge of a wing as oppose to the standard straight or sharp trailing edge. A CAD model with straight leading edge and trailing edge was prepared with NACA 0016 using SolidWorks 2017. The operating conditions were setup such that the inlet speed varies from 0.1 to 0.5 m/s representing a Reynolds number 27.8 x 10ᵌ and 53 x 10ᵌ.The static pressure at different angles of attack (AOA) which varies from 2 to 16degrees at the increment of 2degrees for three turbulent models (K-Ԑ-standard, K-Ԑ-RNG and K-Ԑ-Realizable), was computed for upper and lower surfaces of the modified wing model using ANSYS Fluent 18.1. Thereafter the static pressure distribution, lift coefficient, drag coefficient, lift to drag ratio and pressure coefficient for both upper and lower surfaces were analysed. The findings showed that the lift and drag coefficient are influenced by the AOA and the inlet speed. If these parameters change the performance of the underwater glider changes as depicted by figure 5.6 and figure 5.7. The hydrodynamics of the underwater glider wing is optimized using the Cʟ/Cᴅ ratio as function of the operating conditions (AOA and the inlet speed). The investigation showed that the optimal design point of the AOA of 12 degrees and a corresponding inlet speed of 0.26m/s. The critical AOA matched with the optimal design point AOA of 12 degrees. It was also observed that Cp varies across the wing span. The results showed the Cp is higher closer to the fuselage while decreasing towards the mid-span and at the tip of the wing. This showed that the wing experiences more stress close to the fuselage than the rest of the wing span which implies that a higher structural rigidity is required close to the fuselage. The results of the drag and lift curves correspond to the wing characteristics typical observed for this type of aerofoil.

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Currently, buoyancy driven underwater gliders are deployed globally to gather oceanographic data from across the worlds oceans. This thesis examines the utility of underwater gliders within the context of providing additional U.S. Navy capabilities. An extensive survey of available underwater gliders was undertaken and the resultant survey pool of ten gliders down selected to five gliders of fixed wing configuration. A comprehensive architectural analysis was then conducted of seven key architectural attributes of the five selected gliders. The architectural analysis compared various implementations of the key architectural attributes relative to desirable traits and capabilities for a notional U.S. Navy glider. Following the architectural analysis a proposed architecture for a U.S. Navy underwater glider was developed which includes a compendium of best features gleaned from the architectural analysis. Drivers and rationale for selection of specific key architectural attributes and features are also provided. Additionally, a comparison of constraints and capabilities of underwater gliders is provided. Finally, a comparison of the current and proposed capabilities of underwater gliders versus other Autonomous Undersea Vehicles, specifically Unmanned Undersea Vehicles, is proffered.

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A preliminary theoretic flutter analysis of the new JS1 18m-class glider was performedby means of analytic methods. This analysis consisted of a detailed modal analysisusing finite element modelling followed by the flutter prediction.The modal analysis was computed with the aid of the commercial FE-code ANSYS inwhich a model of the complete glider was generated. This model was created in such away as to effectively simulate the composite characteristics, while also ensuring that theresults were easily extractable for flutter prediction input. By using the Block-Lanczosmethod, the 1st, 2nd, and 3rd main wing bending and torsion modes as well as the T-tailconfiguration modes were all extracted in the frequency range from 0 - 30 Hz. Thesemodal results, which included the natural frequencies, mode shapes and displacementswere then used as the input for the flutter code.The flutter prediction was done with the software code SAF (Subsonic AerodynamicFlutter). This prediction made use of a complete panel model for the glider, while theflutter algorithm was solved with the p-k method. The flutter results, in the form of V-gand V-f graphs, all showed main mode stability over the entire velocity range of 1.2V,up to an altitude of 25000 ft.
Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.

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In this study, Computational Fluid Dynamics (CFD) simulations have been carried out in order to investigate and improve the performance of the Standard Cirrus glider, using different Navier-Stokes methods and solving the equations for the steady flow. The work has been divided in two parts: First, a study is performed to test the quality of the transition model (Gamma-ReTheta). The two dimensional results of the glider´s airfoil are compared against the results from panel’s methods and the open-source CFD codes: SU2 and OpenFoam. In addition, three dimensional glider´s models are simulated using the transition model with the purpose of creating a validated reference model of the glider’s performance in steady level flight. The simulations are carried out in two dimensions for the outer wing airfoil for a 1.5 e+06 Reynolds number and in three dimensions for the Wing & Fuselage model and Tail & Fuselage model under a range of velocities. Both simulations are validated against experimental data. In the second part of the study, the validated model is used to developed possible improvements in the glider´s external geometry that could produce possible benefits in the performance and handling qualities of the glider.

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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2004.220 leaves single printed pages ,preliminary pages i-xiv and numberd pages 1-188.Includes bibliography.list of figures and used a Hp Scanjet 8250 Scanner to pdf format (OCR),
ENGLISH ABSTRACT: This thesis describes the process followed to determine the short-term control and stabilityderivatives of an ASK-13 glider (ZS-GHB). The short-term control and stability derivatives areobtained by parameter estimation done using data recorded in flight. The algorithm used is theMMLE3 implementation of a maximum likelihood estimator.To collect the flight data sensors were installed in the ZS-GHB. Sensors measuring thecontrol surface deflections, translation acceleration, angular rates and the dynamic and staticpressure are needed to provide enough data for the estimation. To estimate accurate derivativesspecific manoeuvres were flown by the pilot, to ensure that all the modes of the glider werestimulated.The results reveal that the control and stability derivatives estimated from the flight data arenot very accurate but are still suitable to be used in simulating the glider's motion.
AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die proses wat gebruik is om die kort periode beheer en stabiliteit afgeleidesvan 'n ASK-13 sweeftuig vas te stel. Die kort periode beheer en stabiliteit afgeleides isverkry deur parameter afskatting op data wat gedurend vlugte van die sweeftuig opgeneem is.Die algoritme wat gebruik is om die parameters af te skat is die MMLE3 voorstelling van 'nmaksimale moontlikheid afskatter.Om vlug data te versamel sensore moes in die sweeftuig geinstalleer word. Die sensore meetbeheer oppervlak hoeke, versnellings, hoeksnellhede en die dinamies en statiese lugdruk om teverseker dat daar genoeg data is vir die afskatting. Om die afgeskatte parameters akkuraad tekry moet die loods spesefieke manoeuvres vlieg om seker te maak dat al die moduse van diesweeftuig is gestimuleer.Die resultate wat gelewer is 'n stel kort periode beheer en stabiliteit afgeleides wat nieakkuraad is nie, maar wat weI goed genoeg is or ie bewegings van die sweeftuig te simuleer.

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Diplomová práce se zabývá aerodynamickou analýzou a optimalizací wingletu kluzáku. Winglet je uvažován s možností změny tvaru v průběhu letu a optimalizační proces je zaměřen na odhalení optimálních tvarů v odlišných letových režimech. První část práce popisuje současné snahy v oblasti návrhu a vývoje wingletů s měnitelnou geometrií. Druhá část je zaměřena na popis funkce wingletu, následována třetí částí, která popisuje optimalizační metody, které mohou být použity během optimalizace. Další částí práce je popis letadla vybaveného wingletem, který byl vybrán pro optimalizaci. Tato část je následována požadavky stavebního předpisu kategorie letadla, které bylo vybráno. Následuje model typického letu tohoto letadla. Zbytek práce je organizován dle procesu hledání optimálních tvarů wingletu. Popis tvorby CAD modelu je následován popisem tvorby CFD modelu a popisem přípravy CDF simulací. V předposlední kapitole jsou odhaleny detaily optimalizačního procesu. Závěrečná část práce obsahuje vyhodnocení výsledků optimalizačního procesu.

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This master thesis is focused on aerodynamic design of transonic glider, which is assigned for following an airliner at cruising regime of flight. Main goal of the thesis is to determine basic geometrical design of airplane with respect to Whitcomb aera rule, mass analysis and drag polar. Weight analysis includes determining center of gravity according to longitudinal static stability margin. The drag polar of the airplane is determine for cruising regime of flight, that means the regime of following an airliner.

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L'équilibre énergétique de l'océan traduit des échanges d'énergie entre les termes sources aux échelles planétaires et la dissipation aux micro-échelles. Cette cascade d'énergie, cruciale dans la compréhension du système océanique, demande à être mieux comprise et quantifiée. La plus grande part de l'énergie dans l'océan est associée à la dynamique mésoéchelle. Les échelles spatiales correspondantes sont aussi celles des marées internes et dans les régimes océaniques où l'énergie des ondes internes est suffisamment forte celles-ci représentent un transfert d'énergie majeur vers les échelles dissipatives. La nouvelle mission satellite SWOT (Surface Water Ocean Topography) permettra d'observer globalement pour la première fois ces processus de fines échelles. Une motivation de cette thèse est l'observabilité du niveau de la mer SWOT avec le challenge de comprendre la part respective de la dynamique méso et sous-mésoéchelle et des ondes internes. La région d'étude se situe autour de la Nouvelle Calédonie dans le Pacifique sud-ouest et plus particulièrement dans la région sud survolée par une fauchée SWOT lors de la phase de cal-val du satellite caractérisée par une orbite à 1 jour. La thèse s'appuie sur une simulation régionale dédiée à haute résolution (1/60°) forcée ou pas par la marée barotrope en plus des forçages "classiques". Pour la première fois la dynamique des marées internes autour de la Nouvelle-Calédonie est décrite. Cette région s'avère être un hot spot de génération de marées internes associé aux principales structures bathymétriques,. La marée interne est principalement semi diurne. Elle se caractérise par un premier mode barocline très important et une forte signature dans la SSH (>6cm). Cette énergie de marée interne se propage dans l'océan ouvert à partir de deux zones localisées au nord et au sud de la Nouvelle Calédonie malgré des taux de dissipation d'énergie élevés à proximité des zones de génération. Cette propagation est majoritairement associée à de la marée interne cohérente mais l'activité méso-échelle s'avère être une source potentielle de perte de cohérence de la marée interne (marée incohérente). Cette marée interne incohérente est associée aux interactions avec les tourbillons océaniques soit par la réfraction de la propagation de l'énergie du faisceau de marée par les courants à méso-échelle lors de la propagation de l'énergie de marée, soit par les variations de la conversion de l'énergie barotrope en énergie barocline dues aux changements de stratification induits par les tourbillons à méso-échelle. Des observations in situ obtenues par des planeurs sous-marins autonomes révèlent le réalisme du modèle numérique quant à la simulation des marées internes tout en s'avérant être une plateforme in-situ appropriée pour documenter les marées internes, y compris leur signature de la SSH. Dans les régions de forte marée interne, celle-ci domine la variance de la SSH pour des longueurs d'onde jusqu'à 200 km correspondant. Une attention particulière est accordée à la marée incohérente, qui se manifeste dans la SSH à des échelles inférieures à 100 km. Cette thèse initie également l'étude de l'impact des marées internes sur la circulation à méso-échelle et sous-méso-échelle, avec des voies prometteuses pour les travaux futurs sur les échanges d'énergie entre les échelles et la fermeture du bilan énergétique océanique. Ces travaux participeront à la valorisation des données SWOT dans le cadre de SWOT-AdAC avec la campagne SWOTALIS. Enfin, ils sont une première initiative dans l'implication des marées internes en lien avec l'écosystème marin de la Nouvelle-Calédonie associée à un objectif de mise en place d'aires marines protégées au sein du parc naturel de la mer de Corail
The oceanic energy cascade and the associated redistribution of energy from planetary scales to microscales are crucial to achieve climate equilibrium, yet they remain to be fully understood and quantified. Among the submesoscale flow regime which is characterized by equal contributions from rotational (balanced) and non-rotational (unbalanced) effects, it is internal tides (internal gravity waves at tidal frequency) which have been shown to represent a major energy transfer toward dissipative scales. The Surface Water Ocean Topography (SWOT) satellite mission will push forward global sea surface height (SSH) observations of fine-scale physics of combined balanced and unbalanced motions, and their interactions. Our understanding of these processes will ultimately depend on our ability to disentangle these two different dynamical flow regimes. This thesis aims to tackle SWOT SSH observability of balanced and unbalanced motions around New Caledonia, an area with pronounced internal tide activity alongside elevated level of mesoscale to submescale eddy variability located beneath two swaths of SWOT's fast-sampling phase during which SWOT orbited on a 1-day repeat cycle to collect high-frequency measurements. As an initial step, this thesis provides the first comprehensive description of internal-tide dynamics around New Caledonia, an internal generation hot spot in the southwestern tropical Pacific that has not yet been explored in the literature, based on a tailored regional high-resolution (1/60°) numerical modeling effort. Internal tide generation around New Caledonia is associated with the main bathymetric structures, i.e. continental slope, shelf breaks, small- and large-scale ridges, and seamounts, strongly dominated by the semidiurnal tide and low-vertical modes, with a strong signature in SSH. It is found to be a major source of tidal energy propagation toward the open ocean despite enhanced energy dissipation rates close to the generation sites. Mesoscale eddy variability is shown to be a potential source for the loss of tidal coherence (or tidal incoherence) due to eddy-internal tide interactions, either through the refraction of tidal beam energy propagation by mesoscale currents toward the open ocean or by mesoscale-eddy induced variations of barotropic-to-baroclinic energy conversion. Important insight is provided by in-situ observations of autonomous underwater gliders. They reveal the numerical model's realism of internal-tide dynamics while proving to be a suitable in-situ platform to infer internal tides, including SSH signature. SWOT SSH observability of balanced and unbalanced motions represent a challenge around New Caledonia as the internal tide dominates SSH variance at wavelengths similar to those of balanced motion at scales less than 200~km wavelength. Particular emphasis is given to the incoherent tide, which manifests in SSH at scales less than 100~km, while restricting the observability of mesoscale and submesoscale motions. An outlook is given on the impact of internal tides on the mesoscale to submesoscale circulation with promising routes for future work on cross-scale energy exchanges and the closure of the oceanic energy budget. Finally, the comprehensive description of internal-tide dynamics conducted in this thesis has important implications for the New Caledonia marine ecosystem, with the hope of paving the way for the island's efforts in the conservation of marine protected areas

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Thesis (M.S.)--West Virginia University, 2007.
Title from document title page. Document formatted into pages; contains viii, 59 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 51-52).

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In this thesis, we analyze the electromagnetic wave propagation in waveguidestructuresexhibiting periodical geometry, including glide symmetry. The analysisis performed using a mode matching technique which correlates the different modecoefficients from separate but, connected regions in the structure. This technique isused to obtain the dispersion diagrams for two one-dimensional periodic structures:a glide-symmetric corrugated metasurface and a coaxial line loaded with periodicholes. The mode matching formulation is presented in Cartesian and cylindricalcoordinate system for the former and the later, respectively. The mode matchingresults are compared to simulated results obtained from the Eigenmode Solver inCST Microwave Studio and are found to agree very well.
I detta examensarbete, analyseras elektromagnetisk v°agutbredning i periodiskav°agledarstrukturer som uppvisar glid symmetri. Analysen genomf¨ordes genom enmod matchnings-teknik som korrelerar de olika mod-koefficienterna fr°an separeraderegioner i strukturen med varandra. Denna teknik anv¨ands f¨or att ta framdispersionsrelationen f¨or tv°a endimensionella periodiska strukturer: en glid symmetriskkorrugerad meta-yta och en koaxial ledare belagd med periodiskt urgr¨opdah°aligheter. Mod matchnings-formuleringen presenteras i Kartesiska och cylindriskakoordinatsystem respektive f¨or de ovan n¨amnda fallen. Mod matchnings-resultatenj¨amf¨ors med data-simulerade resultat erh°allna fr°an CST Microwave Studio och de¨overenst¨ammer v¨al med varandra.

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Les tumeurs cérébrales primaires sont extrêmement agressives, et souvent incurables. Des cellules partageant de nombreuses caractéristiques des cellules souches neurales (CSNs) ont été identifiées dans plusieurs tumeurs cérébrales primaires. Celles-ci sont appelées cellules souches cancéreuses (CSCs) et présentent un potentiel d'autorenouvellement avec une prolifération illimitée. Les tumeurs dépendent fortement de leur microenvironnement cellulaire, qui résulte en parti du remodelage de populations préexistantes, telles que les cellules gliales et les vaisseaux sanguins (la barrière hémato-encéphalique). Dans ce projet, le système nerveux central de la drosophile est utilisé comme modèle in vivo afin de suivre les tumeurs cérébrales tout au long de la vie de l’hôte. Les CSNs de la drosophile représentent un modèle de cellules souches bien caractérisé à partir duquel des tumeurs peuvent être générées au cours du développement de l’hôte, puis survivre et proliférer largement à l’âge adulte. Dans ce système, je peux distinguer différentes populations de cellules dans la niche et explorer leur comportement par rapport aux CSC pendant la croissance tumorale. Je me suis particulièrement intéressé aux mécanismes d'interaction cellulaire qui se produisent dans les cellules gliales à l'interface avec les tumeurs. Mes résultats montrent qu'une sous-population de cellules gliales (les cellules gliales du cortex) subit une apoptose lors de la croissance tumorale, un mécanisme qui semble favoriser la propagation de la tumeur. Lorsque la mort des cellules gliales du cortex est stoppée, la croissance tumorale est réduite, ce qui suggère que la tumeur a, en partie, besoin de la mort des cellules gliales afin de se développer. En retour, une apoptose précoce des cellules gliales du cortex favorise la croissance tumoral, soulignant une interaction à double sens entre ces deux populations. Une analyse transcriptionnelle des cellules gliales du cortex durant la croissance tumorale a révélé des voies de signalisation augmentées ou réduites, et dont la fonction est en train d'être testée. En parallèle, prenant avantage d'une analyse transcriptionnelle de telles tumeur déjà disponible, j'ai sélectionné plusieurs candidats potentiels servant de médiateurs des interactions entre protéines à l'interface entre la tumeur et les cellules gliales. Enfin, j'ai évalué le rôle des protéines Rab dans la croissance tumorale. Ces travaux permettront de mieux comprendre comment les tumeurs des CSN envahissent et progressent dans les tissus sains
Primary brain tumours are extremely aggressive, and often incurable. Interestingly, cells sharing many of the features of neural stem cells (NSCs) have been identified in several primary brain tumors. These cells are coined cancer stem cells (CSCs), and display self-renewal potential with illimited proliferation. Tumours strongly depend on a cellular microenvironment, which results in part from the remodelling of pre-existing populations, such as glial cells and blood vessels (the blood-brain barrier). The project uses the Drosophila Central Nervous System as an in vivo model to track brain tumors during the entire life of the host. The fly NSCs are a well-characterised stem cell model from which tumous can be generated during development, are CSC-driven and can survive and proliferate extensively during adulthood. In this system I can discriminate between different cell populations within the niche, and explore their behavior with respect to the CSCs during tumor growth. In particular I am interested in the mechanisms of cellular interactions happening in glial cells at the interface with the tumors. My results show that a sub-population of glial cells (cortex glia) undergoes apoptosis upon tumor growth, a mechanism that appears to promote tumor propagation. Interestingly, preventing cortex glia death leads to reduced tumor growth, suggesting that the tumour is at least in part required to eliminate glia to grow. In return, precocious killing of cortex glia favors tumor growth, pinpointing a reciprocal relationship between these two cell populations. Performing a transcriptional analysis of cortex glia during tumor growth has revealed multiple signalling pathways with a changing expression, and whose functional relevance is currently being assessed. In parallel, taking advantage of a published tumor transcriptome, I have selected several potential candidates mediating protein protein interactions at the interface between the tumour and the glia cells. Finally, I have also evaluated the role of known Rab proteins in the context of tumor development. This on-going work will shed light on how CNS tumors progress within and invade the healthy tissue

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The North Atlantic Caledonides are a continent-continent collision type orogeny found in WesternScandinavia, Svalbard, Greenland and the British Isles. They are thought to have formed as a result of a complex history consisting of repeated ocean opening and closure. The tectonostratigraphy of the Scandinavian Caledonides consists of four allochthons that overlay the crystalline, autochthonous basem*nt. The allochthons are thought to have been transported hundreds of kilometers eastward during the Scandian collision.To investigate the complex history of the Scandinavian Caledonides, a scientific drilling initiative called the Collisional Orogeny in the Scandinavian Caledonides (COSC) project began in 2014. The first phase of the project was to drill a borehole to approximately 2500m depth, to sample a thick section of the Lower Seve Nappe of the Middle Allochthon, as well as the underlying thrust zone.The current hypothesis is that the Middle Seve Nappe has been juxtaposed with the Lower Seve Nappe while still in the subduction channel. Both Seve nappes were emplaced onto the underlying units somewhat later. To test this hypothesis, Rb-Sr dating and Ar-Ar dating has been conducted on white and dark mica found in samples taken from the shear zones. Rb-Sr dating yielded an age of 413 ± 12 Ma and Ar-Ar dating yielded an average age of 424.1± 2.9 Ma. Since the Rb-Sr and Ar-Ar ages overlap, it is interpreted that the crystallization age of the samples is recorded in both cases. Likely, the rocks cooled rather quickly, resulting in a negligible difference in Rb-Sr and Ar-Ar ages. Comparing these results to previous age dating work completed in the same area illustrate a complex subduction/exhumation history. At c. 455 Ma, the Middle and Lower Seve nappes were subducted beneath an island arc and peak pressure metamorphic conditions were reached. Shortly afterwards,exhumation of the subducted sheet began, as a result of the buoyancy of the subducted crust, as well as tectonic under pressure caused by wedge extraction. At c. 424 Ma, the Middle Seve was juxtaposed over the Lower Seve while still in the subduction channel, and at c. 424 - 421.2 Ma both the Middle and Lower Seve nappes were exhumed and transported eastward, where they were thrust above the underlying Särv Nappe and Lower Allochthon, creating the lower shear zone which is the focus of this study. Data from this study will help to establish a coherent model of mid-Palaeozoic mountain building, and provide insight on how this mountain chain, as well as its Himalaya-Tibet analogue have formed.
Den kaledoniska bergskedjan är en kontinent-kontinent kollison orogenes som återfinns i västra Skandinavien, Svalbard, Grönland och på de brittiska öarna. Bergskedjan har formats som ett resultat av en komplicerad historia av repeterad öppning och stängning av Iapetushavet. Skandinaviska kaledoniderna består av fyra allochthoner som täcker urberggrunden. Allochthonerna tros ha blivit transporterade hundratals kilometer i östlig riktning under den Skandiska kollisionen.För att kunna utreda den komplicerade historia som de skandinaviska Kaledoniderna har så har ett borrningsprojekt tagits fram under år 2014 med namnet “Collisional Orogeny in the Scandinavian Caledonides” (COSC). Det första skedet i projektet var att borra ett 2500 meter djupt borrhål för att ta prover från den undre Seveskollan som belägen i den mellersta allochthonen, samt den underliggande överskjutningszonen.Hypotesen är att den mellersta Seveskollan har placerats intill den undre Seveskollan då de befann sig i en subduktionskanal. Både mellersta och undre Seveskollan har placerats uppepå den underliggande bergsenheten något senare. För att testa hypotesen har Rb-Sr och Ar-Ar datering utförts på prover med vitt glimmer som tagits från skjuvzonen. Kompositionskartor av vitt glimmer påvisar inga uppenbara tecken på zonation, vilket innebär att glimmerkornen nyligen bildats eller omkristalliserats under skjuvning. Rb-Sr dateringen gav en ålder på 413 ± 12 miljoner år och Ar-Ar dateringen gav en ålder på424.1 ± 2.9 miljoner år. Detta tolkas som åldern på de omkristalliserade glimmerkornen.Resultatet har jämförts med tidigare åldersdateringar i samma område och påvisar en komplicerad subduktionshistoria. För 460 miljoner år sedan subducerade mellersta och undre Seveskollan under en öbåge. För ungefär 440 miljoner år började upplyftandet av de subducerade skollorna som ett resultat av bärkraften av den subducerande jordskorpan, även av tektoniska rörelser orsakad av en kilutdragning. För 424 miljoner år sedan blev mellersta Seveskollan placerad ovanpå undre Seveskollan när de befann sig i subduktionskanalen. slu*tligen, för cirka 415 miljoner år sedan blev både den mellersta och undre Seveskollan upplyfta och transporterade i östlig riktning där de skjuvade över den underliggande Särvskollan och den undre allochthonen.Data från denna studie kommer att bidra till skapandet av en följdriktig modell av den mitt-Paleozoiskabergskedjebildningen och

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Ispitivani su dvostruki slojeviti hidroksidi, LDH i mešoviti oksidi nastali njihovomrazgradnjom, sa različitim sadržajem Mg-Al-Fe i proširenom supstitucijom aluminijuma.Koprecipitacione metode male i velike prezasićenosti odabrane su za sintezu LDH opšteformule [Mg1_-x M(III)_x (OH)₂](CO₃)_x/2 ⋅ mH₂O, gde M(III) pretstavlja Al i/ili Fe, a x udeotrovalentnih anjona, x = M(III) / [M(II) + M(III)], variran u intervalu 0,15 < x < 0,7.Katalizatori na bazi mešovitih oksida sa gvožđem pogodni za upotrebu u redoksreakcijama, formirani su nakon termičke aktivacije - razlaganja LDH. Izvršena jekarakterizacija mešovitih oksida nastalih iz LDH, kao i netretiranih LDH, ispitivanjemkristalne strukture (XRD), termičke stabilnosti (TG-DTA), teksture (adsorpcija N₂), redoks(H₂ TPR) i kiselo-baznih karakteristika (NH₃ TPD), a utvrđena je i priroda prisutnih vrstagvožđa (Moessbauer spektroskopija). Pokazano je kako metoda pripreme i obimsupstitucije M(III) jona utiču na strukturne, površinske i redoks karakteristike LDH injihovih mešovitih oksida u korelaciji sa katalitičkim svojstvima u odabranim testreakcijama (razgradnja N₂O i redukcija sa NH₃). Utvrđeno je da na katalitičku aktivnostdominantno utiču redoks karakteristike i priroda vrste gvožđa u mešovitom oksidu, alitakođe i strukturne karakteristike polaznog LDH, pri čemu je površinska struktura aktivnihcentara intervalentnog Fe²⁺-Fe³⁺ gvožđa ključna za redoks procese ispitivanih reakcija.Kod svih mešovitih oksida dobijenih iz LDH aktivni centri imaju relativno jednake jačine,dok razlike u katalitičkom ponašanju potiču od razlika u dostupnosti aktivnih centara.Najbolje performanse u katalitičkim reakcijama pokazali su uzorci sa najmanjomstabilnošću inicijalnih LDH kod kojih je količina supstituisanih M(III) jona bila blizugranice za inkorporaciju u LDH matricu (x = 0,5), a naročito uzorak sintetisan metodomvelike prezasićenosti sa malom količinom dodatne Al(OH)₃ faze.
Layered double hydroxides (LDHs) and derived mixed oxides with different Mg-Al-Fe content and extended aluminum substitution were investigated. High and low supersaturation precipitation methods were used for the synthesis of LDHs with general formula [Mg1_-x M(III)_x (OH)₂](CO₃)_x/2 ⋅ mH₂O where M(III) presents Al and/or Fe and x the content of trivalent ions, x = M(III) / [M(II) + M(III)], varied between 0.15 < x < 0.7. Iron-containing mixed oxides, suitable as catalysts for redox reactions, were formed after thermal activation - decomposition of LDH. Both, LDHs and derived mixed oxides were characterized with respect to crystalline structure (XRD), thermal stability (TG-DTA), textural (N₂ adsorption), redox (H₂ TPR) and acid-base properties (NH₃ TPD) as well as the nature of the iron species (Moessbauer spectroscopy). It was demonstrated how preparation method and the extent of M(III) substitution influence the structure, surface and redox properties of LDHs and derived mixed oxides in correlation to catalytic properties in chosen test reactions (N₂O decomposition and reduction with NH3). The catalytic behavior is mainly determined by the redox properties and the nature of the iron species in mixed oxides, but also by the structural properties of initial LDHs. It was confirmed that surface structure of intervalent Fe²⁺-Fe³⁺ iron active sites is crucial for the redox processes in chosen reactions. The strength of active sites is similar for all mixed oxides derived from LDH, but the differences in catalytic behavior arise from the differences in active sites accessibility. The best catalytic results were obtained when the stability of the initial LDH matrix was lowest e.g. when the amount of substituted M(III) was near the limit for the incorporation into LDH matrix (x = 0.5), especially for the sample synthesized with high superasaturation method containing a small amount of additional Al(OH)₃ phase.

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The underlying research that resulted in this doctoral dissertation was performed at the Division of Economic Geology and Petrology of the Department of Mineralogy, TU Bergakademie Freiberg between 2011 and 2014. It was the primary aim of this thesis to develop and test novel applications for the technology of ‘Automated Mineralogy’ in the field of economic geology and geometallurgy. A “Mineral Liberation Analyser” (MLA) instrument of FEI Company was used to conduct most analytical studies. This automated system is an image analysis system based on scanning electron microscopy (SEM) image acquisition and energy dispersive X-ray spectrometry which can be used to determine both quantitative mineralogical data and mineral processing-relevant parameters. The analyses can be conducted with unconsolidated and solid rocks but also with ores and products of the mineral processing and recycling industry. In consequence of a first-time broadly-based and comprehensive literature review of more than 1,700 publications related to all types of automated SEM-based image analysis systems several trends in the publication chronicle were observed. Publications related to mineral processing lead the field of automated mineralogy-related publications. However, this is with a somewhat smaller proportion than expected and with a significant decrease in share between around 2000 and 2014. The latter is caused by a gradual but continuous introduction of new areas of application for automated mineralogical analysis such as the petroleum industry, petrology or environmental sciences. Furthermore, the quantity of automated mineralogy systems over time was carefully assessed. It is shown that the market developed from many individual developments in the 1970s and 1980s, often conducted from research institutes, e.g., CSIRO and JKMRC, or universities, to a duopoly - Intellection Pty Ltd and JKTech MLA - in the 1990s and 2000s and finally to a monopoly by FEI Company since 2009. However, the number of FEI’s competitors, such as Zeiss, TESCAN, Oxford Instruments, and Robertson CGG, and their competing systems are increasing since 2011. Particular focus of this study, published in three research articles in peer-reviewed international journals, was the development of suitable methodological approaches to deploy MLA to new materials and in new contexts. Data generated are then compared with data obtained by established analytical techniques to enable critical assessment and validation of the methods developed. These include both quantitative mineralogical analysis as well as methods of particle characterisation. The first scientific paper “Use of Mineral Liberation Analysis (MLA) in the Characterization of Lithium-Bearing Micas” deals with the field of mineral processing and describes the characterisation of lithium-bearing zinnwaldite mica - as potential natural resource for lithium - by MLA as well as the achievement of mineralogical association data for zinnwaldite and associated minerals. Two different approaches were studied to comminute the samples for this work, conventional comminution by crusher as well as high-voltage pulse selective fragmentation. By this study it is shown that the MLA can provide mineral data of high quality from silicate mineral resources and results very comparable to established analytical methods. Furthermore, MLA yields additional relevant information - such as particle and grain sizes as well as liberation and grade-recovery data. This combination of quantitative data cannot be attained with any other single analytical method. The second article “Characterisation of graphite by automated mineral liberation analysis” is also located in the field of mineral processing. This research article is the first published contribution on the characterisation of graphite, an important industrial mineral, by MLA respectively an automated mineralogy-related analytical method. During this study graphite feeds and concentrates were analysed. By this study it is shown that it is possible to gather statistically relevant data of graphite samples by MLA. Furthermore, the MLA results are validated by quantitative X-ray powder diffraction as well as particle size determinations by laser diffraction and sieve analysis. The third research paper “Nature and distribution of PGE mineralisation in gabbroic rocks of the Lusatian Block, Saxony, Germany” deals with the scientific field of geoscience. In this study it is shown that it is possible to obtain a significant body of novel mineralogical information by applying MLA analysis in a region previously regarded as being well-studied. The complex nature and relatively large distribution of the occurring platinum group minerals (PGM) is well illustrated by this contribution. During previous light microscopic studies and infrequent electron microprobe measurements only a handful isolated PGM grains were identified and characterised. In this investigation, using the samples of previous studies, 7 groups of PGM and 6 groups of associated tellurides as well as in total more than 1,300 mineral grains of both mineral groups were identified. Based on the data obtained, important insight regarding mineral associations, mineral paragenesis and the potential genesis of the PGM is obtained. Within this context, the value of MLA studies for petrological research focused on trace minerals is documented. MLA yields results that are both comprehensive and unbiased, thus permitting novel insight into the distribution and characteristics of trace minerals. This, in turn, is immensely useful when developing new concepts on the genesis of trace minerals, but may also give rise to the development of a novel generation of exploration tools, i.e., mineralogical vectors towards exploration akin to currently used geochemical vectors. The present dissertation shows that automated mineralogy by using a Mineral Liberation Analyser is able to deliver a unique combination of quantitative data on mineralogy and several physical attributes that are relevant for ore geology and mineral processing alike. It is in particular the automation and unbiasedness of data, as well as the availability of textural data, size and shape information for particles and mineral grains, as well as mineral association and mineral liberation data that define major advantages of MLA analyses - compared to other analytical methods. Despite the fact that results are obtained only on 2-D polished surfaces, quantitative results obtained compare well/very well to results obtained by other analytical methods. This is attributed mainly due to the fact that a very large and statistically sound number of mineral grains/particles are analysed. Similar advantages are documented when using the MLA as an efficient tool to search for and characterise trace minerals of petrological or economic significance
Die Forschung die der vorliegenden kumulativen Dissertation (‚Publikationsdissertation‘) zugrunde liegt wurde im Zeitraum 2011-2014 am Lehrstuhl für Lagerstättenlehre und Petrologie des Institutes für Mineralogie der TU Bergakademie Freiberg durchgeführt. Das primäre Ziel dieser Arbeit war es neue Einsatzmöglichkeiten für die Technik der Automatisierten Mineralogie im Gebiet der Lagerstättenkunde und Geometallurgie zu entwickeln und zu testen. Im Mittelpunkt der wissenschaftlichen Studien stand die analytische Nutzung des Großgerätes „Mineral Liberation Analyser“ (MLA) der Firma FEI Company. Dieses automatisierte System ist ein Bildanalysesystem und basiert auf der Erfassung von Rasterelektronenmikroskopiebildern und energiedispersiver Röntgen-spektroskopie. Mit Hilfe der MLA-Analysetechnik lassen sich sowohl statistisch gesichert quantitative mineralogisch relevante als auch Aufbereitungsprozess-relevante Parameter ermitteln. Die Analysen können sowohl an Locker- und Festgesteinen als auch an Erzen und Produkten der Aufbereitungs- und Recyclingindustrie durchgeführt werden. Infolge einer erstmaligen, breit angelegten und umfassenden Literaturrecherche von mehr als 1.700 Publikationen im Zusammenhang mit allen Arten von automatisierten REM-basierten Bildanalysesystemen konnten verschiedene Trends in der Publikations¬historie beobachtet werden. Publikationen mit Bezug auf die Aufbereitung mineralischer Rohstoffe führen das Gebiet der Automatisierte Mineralogie-bezogenen Publikationen an. Der Anteil der Aufbereitungs-bezogenen Publikationen an der Gesamtheit der relevanten Publikationen ist jedoch geringer als erwartet und zeigt eine signifikante Abnahme des prozentualen Anteils zwischen den Jahren 2000 und 2014. Letzteres wird durch eine kontinuierliche Einführung neuer Anwendungsbereiche für die automatisierte mineralogische Analyse, wie zum Beispiel in der Öl- und Gasindustrie, der Petrologie sowie den Umweltwissenschaften verursacht. Weiterhin wurde die Anzahl der Systeme der Automatisierten Mineralogie über die Zeit sorgfältig bewertet. Es wird gezeigt, dass sich der Markt von vielen einzelnen Entwicklungen in den 1970er und 1980er Jahren, die oft von Forschungsinstituten, wie z. B. CSIRO und JKMRC, oder Universitäten ausgeführt wurden, zu einem Duopol - Intellection Pty Ltd und JKTech MLA - in den 1990er und 2000er Jahren und schließlich seit 2009 zu einem Monopol der FEI Company entwickelte. Allerdings steigt die Anzahl der FEI-Konkurrenten, wie Zeiss, TESCAN, Oxford Instruments und Robertson CGG, und deren Konkurrenzsysteme seit 2011. Ein Schwerpunkt der drei von Experten begutachteten und in internationalen Fachzeitschriften publizierten Artikel dieser Studie war die Entwicklung eines geeigneten methodischen Ansatzes um die MLA-Technik für neue Materialien und in neuem Kontext zu verwenden. Die erzeugten Daten wurden mit Daten die von etablierten analytischen Techniken gewonnen wurden verglichen, um eine kritische Bewertung und Validierung der entwickelten Methoden zu ermöglichen. Dazu gehören sowohl quantitative mineralogische Analysen als auch Methoden der Partikelcharakterisierung. Der Schwerpunkt der Studie zum ersten Fachartikel „Use of Mineral Liberation Analysis (MLA) in the Characterization of Lithium-Bearing Micas“ liegt im Gebiet der Aufbereitung mineralischer Rohstoffe. Er beschreibt die Charakterisierung von Zinnwaldit-Glimmer - einem potentiellen Lithium-Rohstoff - durch die MLA-Technik sowie das Erringen von Mineralverwachsungsdaten für Zinnwaldit und assoziierter Minerale. Dabei wurden zwei unterschiedliche Wege der Probenzerkleinerung des Rohstoffes untersucht. Zum einen erfolgte eine konventionelle Zerkleinerung der Proben mittels Brecher und Mühle, zum anderen eine selektive Zerkleinerung durch Hoch¬spannungsimpulse. Es konnte aufgezeigt werden, dass die automatisierte Rasterelektronen¬mikroskopie-basierte Bildanalyse mittels MLA von silikatischen Rohstoffen Mineral¬informationen von hoher Güte zur Verfügung stellen kann und die Ergebnisse gut vergleichbar mit etablierten analytischen Methoden sind. Zusätzlich liefert die MLA weitere wertvolle Informationen wie zum Beispiel Partikel-/Mineralkorngrößen, Aussagen zum Mineralfreisetzungsgrad sowie Gehalt-Ausbring-Kurven des Wertstoffes. Diese Kombination von quantitativen Daten kann mit keiner anderen analytischen Einzelmethode erreicht werden. Der zweite Fachartikel „Characterisation of graphite by automated mineral liberation analysis“ ist ebenfalls im Fachgebiet der Aufbereitung mineralischer Rohstoffe angesiedelt. Während dieser Studie wurden Edukte und Produkte der Aufbereitung von Graphit-Erzen untersucht. Der vorliegende Artikel ist der erste in einer internationalen Fachzeitschrift publizierte Beitrag zur Charakterisierung des Industrieminerals Graphit mittels MLA-Technik bzw. einer Analysenmethode der Automatisierten Mineralogie. Mit der Studie konnte gezeigt werden, dass es möglich ist, auch mit der MLA statistisch relevante Daten von Graphitproben zu erfassen. Darüber hinaus wurden die Ergebnisse der MLA-Analysen durch quantitative Röntgenpulverdiffraktometrie sowie Partikelgrößen-bestimmungen durch Laserbeugung und Siebanalyse validiert. Der dritte Fachartikel „Nature and distribution of PGE mineralisation in gabbroic rocks of the Lusatian Block, Saxony, Germany“ ist im Gegensatz zu den ersten beiden Artikeln im Gebiet der Geowissenschaften angesiedelt. In dieser Studie wird gezeigt, dass es möglich ist mittels MLA-Analyse eine signifikante Anzahl neuer Daten von einem eigentlich schon gut untersuchten Arbeitsgebiet zu gewinnen. So konnte erst mit der MLA die komplexe Natur und relativ große Verbreitung der auftretenden Platingruppenelement-führenden Minerale (PGM) geklärt werden. Während früherer lichtmikroskopischer Analysen und einzelner Elektronenstrahlmikrosonden-Messungen konnten nur eine Handvoll weniger, isolierter PGM-Körner nachgewiesen und halbquantitativ charakterisiert werden. In der vorliegenden Studie konnten nun, an den von früheren Studien übernommenen Proben, 7 PGM-Gruppen und 6 assoziierte Telluridmineral-Gruppen mit insgesamt mehr als 1.300 Mineralkörnern beider Mineralgruppen nachgewiesen werden. Auf der Grundlage der gewonnenen Daten wurden wichtige Erkenntnisse in Bezug auf Mineralassoziationen, Mineralparagenese und zur möglichen Genese der PGM erreicht. In diesem Zusammenhang wurde der Wert der MLA-Studien für petrologische Forschung mit dem Fokus auf Spurenminerale dokumentiert. Die MLA liefert Ergebnisse, die sowohl umfassend und unvoreingenommen sind, wodurch neue Einblicke in die Verteilung und Charakteristika der Spurenminerale erlaubt werden. Dies wiederum ist ungemein nützlich für die Entwicklung neuer Konzepte zur Genese von Spurenmineralen, kann aber auch zur Entwicklung einer neuen Generation von Explorationswerkzeugen führen, wie zum Beispiel mineralogische Vektoren zur Rohstofferkundung ähnlich wie derzeit verwendete geochemische Vektoren. Mit der vorliegenden Dissertationsschrift wird aufgezeigt, dass Automatisierte Mineralogie mittels Mineral Liberation Analyser eine einzigartige Kombination an quantitativen Daten zur Mineralogie und verschiedene physikalische Attribute, relevant sowohl für die Lagerstättenforschung als auch für die Aufbereitung mineralischer Rohstoffe, liefern kann. Im Vergleich zu anderen etablierten analytischen Methoden sind es insbesondere die Automatisierung und Unvoreingenommenheit der Daten sowie die Verfügbarkeit von Gefügedaten, Größen- und Forminformationen für Partikel und Mineralkörner, Daten zu Mineralassoziationen und Mineralfreisetzungen welche die großen Vorteile der MLA-Analysen definieren. Trotz der Tatsache, dass die Ergebnisse nur von polierten 2-D Oberflächen erhalten werden, lassen sich die quantitativen Ergebnisse gut/sehr gut mit Ergebnissen anderer Analysemethoden vergleichen. Dies kann vor allem der Tatsache zugeschrieben werden, dass eine sehr große und statistisch solide Anzahl von Mineralkörnern/Partikeln analysiert wird. Ähnliche Vorteile sind bei der Verwendung der MLA als effizientes Werkzeug für die Suche und Charakterisierung von Spurenmineralen von petrologischer oder wirtschaftlicher Bedeutung dokumentiert

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Wir haben blau, grün und orange leuchtende organische Nanofäden oder Nanonadeln und Mikroringe aus para-Hexaphenyl (p-6P), alpha-Quaterthiophen (alpha-4T) und alpha-Sexithiophen (alpha-6T) mittels Organischer Molekularstrahlepitaxie (OMBE) auf Muskovit Glimmer hergestellt. Die Aggregate haben wir mit der Atomkraftmikroskopie, mit der Fluoreszenz-Mikroskopie und durch UV-vis Spektroskopie charakterisiert. Auf der Muskovit Oberfläche wachsen p-6P Fäden parallel zueinander auf und zeigen zwei verschiedene Orientierungsdomänen entlang [110] und [1-10]. Mit Hilfe einer systematischen statistischen Analyse diskutieren wir das Wachstum dieser p-6P Nadeln für verschiedene Wachstumsbedingungen. Zusätzlich zu den Fäden haben wir p-6P Cluster auf der Oberfläche beobachtet. Nadeln werden durch die Aggregation solcher Cluster gebildet. Ein Realraummodell der Morphologie der Nadeln sowie ein Modell für deren Wachstum werden vorgestellt. Indem wir Glimmer zunächst mit einer dünnen Goldschicht bedecken und die Wachstumsparameter variieren, erreichen wir eine weitgehende Kontrolle der Morphologie der Nadeln (Länge von 0,5 Mikrometer bis 1 mm, Höhe von 25 bis 300 nm und Breite von 100 bis 600 nm). Im Gegensatz zu p-6P orientieren Thiophene ihre Wachstumsrichtungen an allen hoch symmetrischen Richtungen von Glimmer. Es wird gezeigt, dass die Mechanismen für das Fadenwachstum von beiden Oligomere gleich sind, nämlich eine Kombination aus Epitaxie und einer Dipol-unterstützten Ausrichtung. Auch die Strukturen dieser Fäden sind ähnlich: die Moleküle liegen parallel angeordnet auf der Oberfläche, ihre Längsachsen orientieren sich schräg zur Längsachse der Fäden. Auf mit Wasser oder Methanol vorbehandeltem Glimmer wachsen diese beiden Oligomere als gebogene Fäden und Mikroringe auf. Diese Oberflächenvorbehandlungen sowie das Wachstum von p-6P auf Gold/Glimmer unterstützen auch den Wachstumsmechanismus auf der sauberen Glimmer-Oberfläche.
By using organic molecular beam epitaxy (OMBE) blue, green and orange light emitting organic nanofibers or nanoneedles and microrings from para-hexaphenyl (p-6P), alpha-quaterthiophene (alpha-4T) and alpha-sexithiophene (alpha-6T), respectively, on muscovite mica surfaces are generated. The aggregates are characterized by atomic force microscopy, fluorescence microscopy and UV-vis spectroscopy. On muscovite mica, p-6P fibers usually grow mutually parallel showing two domains of their orientations with an angle of 120 degree in between. The detail growth of nanofibers from p-6P by performing a systematic statistical analysis of fibers as a function of various growth conditions is discussed. Furthermore, the morphology exhibits p-6P clusters, which are found to be fibers´ building blocks. A real space model of the fiber and a model for their growth are also presented. By introducing a thin gold layer on mica prior to p-6P deposition together with varying growth parameters, the morphology of fibers is controlled in a wide range (length from 0.5 micrometer to 1 mm, height from 25 to 300 nm and width from 100 to 600 nm). In contrast to p-6P, thiophene fibers exhibit various orientations close to mica high symmetry directions. It is shown that the mechanism behind the fiber growth from all molecules on mica is the same, i.e. a combination of epitaxy and dipole assisted growth process. The fiber microscopic structures are similar, too: molecules take lying orientations and they hold themselves parallel pointing their long axes along an oblique direction off the long fiber axis. The growth of both types of oligomers on water or methanol treated mica surfaces leads to the formation of bent fibers and microrings. This surface pretreatment and the growth of p-6P on gold/mica support the fiber growth mechanism on plain mica.

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碩士
國立臺灣大學
工程科學及海洋工程學研究所
96
Autonomous Underwater Glider is a new invention of Autonomous Underwater Vehicle (AUV) in recent years. Underwater Glider has long duration and long range, especially for an apparatus is called CTD sensor that could also collect many physical data of the ocean.Most of CTD sensors are placing for underneath one side of wing of underwater glider therefore the dynamic characteristics of an underwater glider depends on its hydrodynamic coefficients significantly. The variety of geometry has extremely effect to hydrodynamic coefficients, so it is important to estimate or analyze the difference between hydrodynamic coefficients which has the set of CTD sensor or not of underwater glider.The computation of fluid dynamics software “FLUENT” is used for this study. In order to make sure the numerical approaches and mesh arrangement in determining the hydrodynamic coefficients of an underwater glider are appropriate. The first stage is using the data of 4621 axial symmetric submerged body reported by DTNSRDC to simulate the hydrodynamic coefficients. As the result of 4621 simulation is closed to experimental data, then we can use the same numerical approaches and mesh arrangement to calculate the hydrodynamic coefficients of underwater glider at angles of pitch from -25 to +25 degrees which has CTD sensor or not.

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碩士
國立臺灣大學
工程科學及海洋工程學研究所
96
Autonomous underwater glider is a kind of underwater vehicles which is suitable for measuring and collecting large-scale underwater hydrographic information. The gliding principle of an underwater glider is being means of buoyancy engines to inside the glider control a ballast tank for intaking and expelling water. Thereby, difference between buoyancy and weight, and also difference in distance between center-of-buoyancy and center-of-gravity can be produced. These differences will result in an inclination and up-and-down motion of the fuselage. Furthermore, in cooperation with shifting and rotating of the internal moving weight and control of the operable rudder for producing pitch , roll and yaw motion.The purpose of this study is to develop a computer-aided design tool for an underwater glider. Rhino is a commercial CAD software which provides software development kit for building up a design tool to meet special purpose. One can use this development kit to connect with functions of Rhino, assemble different existing programs and export various information such as volume, mass, coordinates of center-of-buoyancy, and center-of-gravity, etc. Besides, the tool exports some files including engineering drawing, three dimensions solid model, Microsoft excel charts, and animation of simulating results for glider motion, etc. The designer can use this information to enhance efficiency for design work and reduce computation errors, so the time needed for design of an underwater glider can be shortened to a large extent.

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Finite element analysis with explicit time integration is widely used in commercial crash solversto accurately simulate transient structural problems involving large-deformation and nonlinearity.Technological advances in computer software and hardware have expanded the boundaries ofcomputational expense, allowing designers to analyse increasingly complex structures ondesktop computers. This dissertation is a review of the use of finite element analysis for crashsimulation, the principles of crashworthy design and a practical application of these methodsand principles in the development of a concept energy absorber for a sailplane. Explicitnonlinear finite element analysis was used to do crash simulations of the glass, carbon andaramid fibre co*ckpit during the development of concept absorbers. The SOL700 solutionsequence in MSC Nastran, which invokes the LS-Dyna solver for structural solution, was used.Single finite elements with Hughes-Liu shell formulation were loaded to failure in pure tensionand compression and validated against material properties. Further, a simple composite crashbox in a mass drop experiment was simulated and compared to experimental results. FEA wasused for various crash simulations of the JS1 sailplane co*ckpit to determine its crashworthiness.Then, variants of a concept energy absorber with cellular aluminium sandwich construction weresimulated. Two more variants constructed only of fibre-laminate materials were modelled forcomparison. Energy absorption and specific energy absorption were analysed over the first 515mm of crushing. Simulation results indicate that the existing JS1 co*ckpit is able to absorbenergy through progressive crushing of the frontal structure without collapse of the main co*ckpitvolume. Simulated energy absorption over the first 515 mm was improved from 2232 J for theexisting structure, to 9 363 J by the addition of an energy absorber. Specific energy absorptionduring the simulation was increased from 1063 J/kg to 2035 J/kg.
MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

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Abstract:

碩士
臺灣大學
工程科學及海洋工程學研究所
95
In order to investigate the dynamic characteristics of an autonomous underwater glider, which is under developing in National Taiwan University, it’s necessary to develop a tool to simulate its maneuvering motions. In the present study, modular modeling is adapted to construct the mathematical model for the 6 degree of freedom of maneuvering motions of an AUG for the sake of easy application of existing database or empirical formula in estimating the hydrodynamic forces of elements, such as fuselage, wings, stern vertical fin and interaction among them, at preliminary design stage. It’s a similar way as MMG mathematical model to simulate ship maneuvering motions. In numerical simulation, the derived nonlinear equations of motions are linearized for obtaining the equations that governing the increment of motions at each time step, and then the solved motions increments are integrated and the coupled nonlinear motions of 6 degree of freedom are simulated. Firstly, the dynamic performances of vertical motions of the two types of underwater gliders were investigated by simulation. One type is controlled by longitudinal moving weight and buoyancy engine located fore, another type is controlled by two buoyancy engines located fore and aft but without longitudinal moving weight. Then the effects of main wing location to the dynamic performances are investigated. Finally, the coupled nonlinear motions of 6 degree of freedom controlled by rolling a transverse moving weight were simulated, and applied to investigate the effects of the locations of main wing and vertical tail fin to lateral stability and turning ability. It was confirmed that the simulation tool developed in the present study may be used as a practical tool for designing an underwater glider in the preliminary design stage.

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Abstract:

碩士
臺灣大學
工程科學及海洋工程學研究所
95
Autonomous Underwater Glider (AUG) is a novel kind of autonomousunderwater vehicle that has very long range and very long duration. An underwaterglider is driven by buoyancy engine which could change net buoyancy by expellingor infusing water, and moving weight. Since the dynamic characteristics of anunderwater glider depend on its hydrodynamic coefficients significantly, it’simportant to analyze or estimate the hydrodynamic coefficients with accuracyenough.In the present study, the CFD commercial software FLUENT was used toanalyze the flow field and determine the hydrodynamic coefficients of anunderwater glider. In order to confirm the numerical approaches and mesharrangement in determining the hydrodynamic coefficients of an underwater gliderare appropriate, a comparison calculation was carried out firstly using theexperimental data of 4621 axial symmetric submerged body tested by DTNSRDCand NTU. Then the same numerical approaches and mesh arrangement are appliedto an underwater glider to determine its hydrodynamic coefficients. Estimation usingDATCOM database is also examined by comparing with the CFD results usingFLUENT.

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Abstract:

碩士
國立臺灣師範大學
體育學系
91
Purpose: The purpose of this study was to analyze performances of two male shot-putters who use the rotational and glide technique, to compare the two techniques and to compare them with world-level shot-putters. Three-dimensional analysis method was used. Method: Two Redlake high-speed digital cameras (125Hz) were genlocked to record the three-dimensional shot put motions. The images were digitized by KWON 3D motion analysis system. Conclusions: The main factor affecting the subjects’ releasing velocities is that their rotational throwing movements of preparation and delivery cannot increase the shot velocities. Better shot-putter who used rotational technique prone to have larger toque. A shot-putter who had better performance had larger velocity-change at thrusting. Rotational technique got more angular momentum of body than glide technique. Suggestions: In rotational technique aspect: Accelerating the shot from the preparative duration. Increasing the velocity-change in the duration of delivery and thrusting. In glide technique aspect: Increasing the velocity of the shot at left foot first breaking the contact of the ground. Enhancing the fluency during delivery to accelerate the shot.

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碩士
國立台北師範學院
體育學系碩士班
93
The Biomechanical Analysis of Glide Hitting and Kick Hitting in Baseball Abstract The purpose of this study were to analyze the biomechanical characteristics of glide and kick hitting in baseball which exerted by professional baseball players in Taiwan. Five professional baseball players were selected as the subjects, which body information in average were 29±1.78 in years, 176.4±4.03 cm in height, 78.6±4.15 Kg in weight. The experiment used two JVC-DV 9800 high-speed digital cameras（120Hz）and one AMTI force plate（1200Hz）. The video data was treated by Kwon3D 3.0 motion analysis system. After processing direct linear transformation, we could get actual coordinate data of individual joints. First, the raw data was filtered by which called Butterworth Fourth-order Zero Lag Digital Filter. Thus we could get all of the kinematical parameters include all joint angle and the horizontal displacement of the body center of gravity. Second, processing the calibration of the force plate. We used the software of DASY Lab 6.0 to transfer the voltage data into Newton（nt）. Next, getting the ground reaction force in three axial directions, we built a module in DASY Lab 6.0 to smoothen the raw data with Butterworth low-pass filter. The following are the main results: 1. In kick hitting, the moving forward velocity of bat is the highest when the ball was hit at the right moment, which the left elbow angle is almost 180 degrees and the right elbow angle is between 100-110 degrees. In the hitting process, the displacement of body in backward/forward direction and the resultant velocity with kick hitting are larger than those with glide hitting. In the stride phase, the average angle of left hip and knee joint with glide hitting is smaller than that with kick hitting. The kick hitting withdrawing the forefoot makes the angle of hip and knee small and transfers the body weight distribution. 2. The initial velocity of the ball affects the ball flight distance. In the kick hitting, the average swing velocity is 21.27±0.533m/s and the average instant velocity at hitting moment is 20.37±0.72m/s. The average value with kick hitting is larger than that with glide hitting. Therefore, the faster the swing velocity is, the faster the ball initial velocity is. 3. In all the hitting motion, the force in vertical direction is lager in back-foot during the stance phase. With motion processing, the force move toward forefoot. The largest force of the forefoot in vertical and horizontal direction appears right before the ball hitting moment. And the average value of kick hitting is larger than glide hitting. The reason comes from the different lifting height and the different exerting force. The player exerts the force to ground and to affects all the body segmental to use the ground reaction force to make body rotation and then transfer the force to the bat. 4. The kick hitting could get better rotation benefit and optimum. In the stride phase, angular momentum of the body is increasing by body inertia .In the rotation phase, the velocity increasing of the body center of gravity makes the angular momentum increase. The largest angular momentum appears right before the ball hit. Because the body inertia in ball hitting moment was very small, the angular momentum was mainly affected by angular velocity. In the phase, the average value, largest value and hitting moment value of angular momentum with kick hitting are larger than those with glide hitting. Therefore, the kick hitting could get larger linear and angular momentum. Conclusion：First, in kick hitting, the bat moving forward velocity is the highest when the ball was hit at the right moment, which the left elbow angle is almost 180 degrees. Second, lifting the fore-foot could increase the velocity of body of gravity and hitting velocity. Third, the ground reaction force and body angular momentum in the rotational phase with kick hitting are larger than those in glide hitting. Thus, the hitting velocity, initial velocity of ball and ball velocity at hitting moment with kick hitting are better than those in glide hitting. Therefore, the kick hitting with larger ground reaction force makes the body get faster rotation velocity, more linear momentum and angular momentum.

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A performance analysis for skip and glide is being studied to investigate the potential usage of waverider technology for interplanetary explorations. While the skip and glide equations themselves were first explored by Eggers, this thesis will implement his equations, but then add waverider technology, to determine the possibility of using trajectory assist to navigate around four planets (Earth, Mars, Jupiter and Venus). All trajectory calculations will be based on the waverider lift-to-drag ratios for various planets to determine the maximum range distance. For this research, skip and glide trajectory will be handled separately to determine which is best suited in covering the most distance for a given planet. Ballistic trajectory will only be mentioned in reference to the derivation of the skip trajectory equation, but will not be covered by itself in this research. Hence, it is possible to study a total of 98 cases of skip trajectories, 12 cases of glide trajectories and any additional cases for the four planets.Even though the skip and glide equations bear no planetary effect, all results listed in this research are based on Earth with a waverider lift-to-drag (L/D) ratio of 8.61. For a skip trajectory, the maximum number of skips is set to be 3. A high velocity ratio of 1.0 results in a low incidence angle of 0.1° with the highest range parameter of 3.52 after 3 skips. A low velocity ratio of 0.2, on the other hand, would result in a high incidence of angle of 39.5° with the least range parameter coverage of 0.05.lying the same velocity ratio and lift-to-drag to both skip and glide trajectory calculations result in a big percent difference. For example, a L/D = 8.61 and a velocity ratio (Vf) of 1.0 will have a skip range parameter of 3.52 (22,451.09 km) after 3 skips. The glide range parameter, on the other hand, comes out to be 20.60 (131,389.89 km). The percent increase turns out to be around 485.23%. Based on these numbers, it is clear that using a glide trajectory by itself would gain the most range distance for Earth.

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碩士
國立清華大學
語言學研究所
104
This thesis gives an overview of the Yami phonemic inventory, syllabification, stress, and the interaction of vowel-glide sequences. The three topics are interrelated to each other.This thesis is divided into three parts. The first part discusses the phonemic status of segments through phonological, morphological, and historical evidence. The phonemic statuses of the affricates and pharyngeal segments are the focuses. Yami syllable structure and their constraints for derived syllables [CGV(C)] are depicted in the second part. The third part introduces the underlying glides and derived glides in the OT framework.The voiced uvular fricative /ʁ/ is proved to block vowel deletion in /aʁa/ sequence. Tautosyllabic consonant clusters do not exist in Yami. Epenthesis, affixation or cross-morphemic resyllabification are ways for Yami to repair ill-formed syllables.As for derived syllables, a potential acoustic account for onset and the following vocalic glide [w] in derived syllable [CwV(C)]. I assume that [t͡ɕjV(C)] or [d͡z jV(C)] syllables are developed from optionally derived syllable [CjV(C)] of /CVV(C)/ but now the affricate is phonemic and [CjV(C)] is the surface form of /CV(C)/. It implies that the [CjVC] syllable causes affricates to go through phonemicization, and the glide [j] therefore becomes a transitional segment. It is likely for [ɲ, ɕ, ɮ] becoming phonemic in the future because /n, ʂ, l/ have tendency to form [CjV(C)] syllable.In the third part, the underlying glides and the derived glides are delineated and distinguished. The hierarchy of OT constraints accounts for how underlying glides, epenthetic glides, and vocalic glides interact in prosodic words. The consistent [vocalic] feature and the syllable position are correlated: the [vocalic] feature of the segment determines the segment’s position in a syllable; the [vocalic] feature of an epenthetic glide must fit the syllable structure.

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博士
國立成功大學
醫學工程研究所
105
Manual therapists frequently employ manual techniques such as posterior/anterior (PA) glide techniques to treatment patient with joint hypomobility disorders. Such tasks involve force generated at the tip of the thumb with the relevant muscles assuming the role of stabilizers for the multiarticular chain of the thumb. However, the exact roles of thumb muscles and kinematics while performing manual tasks are not clear. This part of the study had three objectives: (1) To investigate the effect of the experience and different techniques on kinematics and kinetics while performing three posteroanterior (PA) glide mobilization techniques. (2) To investigate the effect of the IP joint flexibility (hitchhiker’s thumb or not) and techniques (two PA glide mobilization and two pinch tasks) on thumb biomechanics. (3) To construct a biomechanical model to estimate forces acting on the joints and individual muscles of the thumb.In part1 (chapter 2), 23 novice participants without any exposure to manual therapy and 15 physical therapists with at least 3 years of orthopedic experience participated. Each participant exerted maximum thumb-tip force on a 6-axis load cell with three different posterior-anterior (PA) glide techniques including unsupported PA glide (T1), PA glide with digits supported (T2) and PA glide with thumb interphalangeal (IP) joint supported by index finger (T3). Surface electromyographic activities of flexor pollicis brevis (FPB), adductor pollicis (ADP), abductor pollicis brevis (APB), and first dorsal interosseus (1stDI)) and kinematics of each thumb joint were collected for analyses. The magnitude of the thumb-tip force generated is influenced not only by the differences in technique employed by the therapists, but also by the general flexibility of the therapists. While participants of both groups generated the same magnitude of force, experienced participants generated less intrinsic muscle activity with a more flexed position at the CMC joint during PA glide mobilization. Novice participants increased activity of their intrinsic muscles in accordance with the stability status of the technique and performed with the CMC angles closer to the neutral position. Physical therapists with excessive thumb flexibility are advised to perform PA glide with IP joint supported (T3) which generated a greater tip force and was more stable among the three techniques employed in the present study. It produced the smallest relative errors in the thumb tip force generated and was executed in a more flexed position in the metacarpophalangeal (MCP) joints.In part 2 (Chapter 3), 33 apparently healthy young participants (hitchhiker group: 8 males and 8 females; non-hitchhiker group: 8 males and 9 females) participated. Each participant exerted 1) thumb tip force on a 6-axis load cell from 25% to 100% maximum force at a 25% increments with two PA glide techniques (unsupported PA glide, T1, and PA glide with digits support, T2); and 2) tip pinch and lateral pinch tasks on a single axis load cell. Surface EMG of extensor pollicis longus (EPL), extensor pollicis brevis (EPB), flexor pollicis longus (FPL), flexor pollicis brevis (FPB), adductor pollicis (ADP), abductor pollicis longus (APL), abductor pollicis brevis (APB), and first dorsal interosseus (1stDI) were collected. Signficant main effects of technque on normalized thumb-tip force generated and on normalized EMG at all force levels except at 25% of maximum were shown. No obvious group (with or without hitchhiker’s thumb) difference (F=0.894, p=0.352) were revealed. While executing pinch tasks, FPL is required to help distal phalanx of the thumb to resist the forces exerted by the index. A greater ADP EMG activity was observed as it serves as a prime mover and is in a mechanically advantageous position. The EMG activity level of the FPB, FPL and ADP suggest that these muscles assume the roles of prime movers in pinch type of activities. However, their roles change to that of stabilizers during the performance of PA glide techniques. Non-hitchhikers seem to be more capable of maintaining the thumb in more neutral position. In part 3 (Chapter 4), a biomechanical model was constructed to estimate joint constraint forces and individual muscle forces while performing unsupported PA glide (T1) and PA glide with digits support (T2). The mobilization technique results in a greater volar-ulnar directed force at the MCP joint and the largest contact forces were found at CMC joint in both groups. In both techniques, larger joint contact force in all three joints and smaller muscle forces (especially FPB, APB, EPB) were estimated in the Experienced Group than the Novice Group. This model, however, failed to estimate a muscle force pattern consistent with the activation pattern of the thumb muscles identified by surface EMG.

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碩士
國立中正大學
運動與休閒教育研究所
103
Purpose: The study was to analysis the crucial kinematics between both of the difference shot put technique at the double-support phase, throwing phase and release phase, and the correlation analysis with the crucial kinematics among the different shot put technique. Methods: By using a camera to capture the throwing motion of the 8 elite shot putters. The 2-D video of the digital and raw data smoothing are using the Kwon 3D motion analysis system. To calculate the step-length, release height, release velocity, release angle, and the angular and angular velocity vary in the lower extremity at the throwing motion phases. Using the Independent-Samples t Test to understand the different throwing technique during the throwing motion, in addition, the different throwing technique for the all kinematics parameters of the relationship were used the Pearson product-moment correlation coefficient for the test, the significant difference was set α = .05. Results: Between the shot put techniques, there was no significant difference in the throwing distance, step-length, release height, release velocity and release angle, but the vary in the angle and angle velocity of the shank, and the total time was found the significant difference between the different shot put techniques. The total time, vary in the angle of the trunk, and vary in the angle velocity of the shank of the glide technique were significant negative relationship with release velocity, but there were significant positive relationship of vary in the angle velocity of the trunk at the release phase and double support phase with the release height. For the rotational technique, we found the release height was significant positive relationship with vary in the angle thigh at the release phase, with vary in the angle of the thigh at the throwing phase, and vary in the angle of the shank at the release, but the release height was significant negative relationship with the vary in the angle velocity of the thigh, the release velocity was significant negative relationship with vary in the angle of the shank at the throwing phase and vary in the angle of the thigh at the release phase, and vary in the angle velocity of the trunk, thigh, and shank. Discussion: Different throwing techniques, there are differences between the action and the overall performance of the operating time compared to rotary short, but each stage is similar to the action time

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碩士
國立成功大學
物理治療研究所
93
Background and Purpose: Pain in joints of the thumb is one of the major occupation- related disorders for orthopaedic physical therapists. Extensive manual tasks involved in their daily activity appear to be the major culprits; among these tasks are the posteroanterior (PA) glide techniques for spinal mobilization/manipulation. Several different PA glide techniques are commonly employed by manual therapists. The performance of these manual techniques is likely to be influenced by factors such as experience and general flexibility as well. However, the differential effects of these PA manipulative techniques on the kinematics and kinetics of the thumb and the EMG activities of related muscles have not yet been studied. The purpose of this study was to investigate the influence of clinical experience, general flexibility and different manipulative techniques on the performance in the thumb.Methods: Fifteen novice subjects (4 males and 11 females, aged 21.9±2.2 yrs) with no clinical experience and fifteen clinical physical therapists (5 males and 10 females, aged 28.0±2.1 yrs) with at least 3 years of orthopaedic experience participated in this study. Each subject performed three different PA glide techniques (PA glide with the thumb unsupported, PA glide with digital support and the PA glide with interphalangeal joint supported by the index) on a force plate while interphalangeal (IP), metacarpophalangeal (MCP) and carpometacarpal (CMC) joints kinematics were tracked by a motion analysis system. The joint angles, maximum thumb-tip force, surface EMG activities of 8 thumb muscles and the Beighton score of each subject were recorded for analyses.Results: There was a negative correlation between the sagittal plane angles (flexion/extension) of the IP and MCP joints except PA glide with IP support in Novice Group (p<0.05). Such relationship was also found between sagittal plane angles of MCP and CMC joints in the Experienced Group (p<0.05). A negative correlation was also found between the Beighton score and the maximum thumb-tip force (p<0.01). The thumb-tip force and EMG activity of the first dorsal interosseous muscle during PA glide with IP support were greater than those of the other two techniques (p<0.05). EMG values in the Experienced Group were smaller than the Novice Group in abductor pollicis brevis (APB), abductor pollicis longus (APL), flexor pollicis brevis (FPB), and flexor pollicis longus (FPL). EMG activities of the extensor pollicis longus (EPL), abductor pollicis longus (APL) and extensor pollicis brevis (EPB) were greater during the unsupported PA glide (p<0.01), comparing with the other two techniques.Conclusions: The results of the present study revealed negative correlation between angles of the IP and MCP, and between those of the MCP and CMC. Subjects with less general flexibility (smaller Beighton score) or when using IP support techniques are capable of exerting greater thumb-tip force. Experienced therapists exhibited less EMG activities and, thus, more efficiency comparing with their novice counterparts in maintaining the stability of the thumb joints.Clinical Relevance: Physical therapists with excessive thumb flexibility are advised to perform the PA glide with IP joint supported to protect the thumb joints from injury.

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碩士
國立臺中教育大學
音樂學系碩士班
101
The French Horn Concerto by Reinhold Moritzevich Glière of the Russia wascomposed in 1951. Glière wrote this concerto in 1951 and dedicated it to ValeriyPolekh. The date and place of the first performance was fixed--May 10, 1951, inLeningrad. The purpose of research is to discuss Glière《Horn Concerto, Op.91 》’sperformance style. In chapter one of this article is about research purposes andmethods. In the second chapter, describes the growing up of Glière 's and his life story, and the creation background of the musical composition. In the third chapter is directed against the concerto that he created《Horn Concerto, Op.91》entering analysing of this concerto. In the fourth chapter is directed against present author's play annotation explanatory note of this composition. The fifth chapter is conclusions. This concerto was possession of the status of the importance of french horn. This concerto ordeal performer endurance and player skills （like fast Staccato, long phrase legato, con sord. ……）Three movements have different melody stytle, sometimes very beautiful melody, but sometimes very strong. Thus become one of important track of french horn.

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The analysis of diaspora and its characteristics have constituted a substantial body of recent studies and researchers in different disciplines have tried to provide a new definition of diaspora. There are several reasons for the growing interest in the notion of diaspora, the most important of which is the possibility it provides to question the basic, yet fundamental concepts. Diaspora breaks the conceptual relations between concepts and their meanings and acts as a third space for them to be redefined all over again. Diaspora deconstructs the meaning of home, identity, culture, language, memories, ethnicity, belonging and traditions and by doing so, forces those in diaspora to re-evaluate the meanings, re-establish the connections and reread themselves using the newly defined concepts.Given that diaspora provides a space for concepts to be in the process of becoming and not being, it also makes it possible for the stereotypes to be revisited and redefined. South Asian Americans are one of the most significant minority groups in the United States who not only contributed to the advancement of the Diaspora literature but also tried to redefine themselves and the existing stereotypes about them. This study aimed to uncover the central framework of the South Asian American Diasporic literature and to investigate the linguistic and literary patterns of it.The evaluation was carried out through the employment of the corpus analytical methods, including keywords, concordance, and collocations on the compiled corpus for this study.The analyses of the corpus revealed the distinguishing features of the South Asian American Diaspora literature written by the female authors and identified the embedded ideas within the context of this group. This study also illustrated the similarities and the differences between thefindings of this study using corpus analytical methods and the literary readings. The findings of this study can be helpful in identifying the benefits of computational criticism in the study of literature.

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碩士
中國文化大學
音樂學系碩士班西洋音樂組
101
In this thesis investigate about Reinhold Gliere

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Ionic polymer metal composites (IPMC) are a new class of smart materials that have attractive characteristics such as muscle like softness, low voltage and power consumption, and good performance in aqueous environments. Therefore, there is a significant motivation for research on design and development of IPMC based biomimetic propulsion systems for underwater vehicles. In aerospace, underwater vehicles finds application for forensic studies of spaceship wrecks, missile fragments and any airplane accidents in sea and ocean terrains. Such vehicles can also survey moons and planets that house water oceans. Among biomimetic swimming systems, fish inspired swimming has gained interest since fish like swimming provides high maneuverability, high cruising speed, noiseless propulsion and efficient stabilization compared to conventional propulsion systems. In this work, the paired pectoral fin based oscillatory propulsion using IPMC for aquatic propulsor applications is studied. Dynamic characteristics of IPMC fin are analyzed using numerical simulations and optimization is used to improve the fin design. A complex hydrodynamic function is used to describe the behavior of an active IPMC fin actuator in water. The structural model of the IPMC fin is obtained by modifying the classical dynamic equation for a slender beam to account for the electromechanical dynamics of the IPMC beam in water. A quasi-steady blade element model that accounts for unsteady phenomena such as added mass effects, dynamic stall, and the cumulative Wagner effect is used to estimate the hydrodynamic performance of the flapping fin. It is shown that the use of optimization methods can lead to significant improvement in performance of the IPMC fin. Further, three fish species with high performance flapping pectoral fin locomotion are chosen and performance analysis of each fin design is conducted to discover the better configurations for engineering applications. Dynamic characteristics of IPMC actuated flapping fins having the same size as the actual fins of three different fish species, Gomphosus varius, Scarus frenatus and Sthethojulis trilineata, are also analyzed. Finally, a comparative study is performed to analyze the performance of the three different biomimetic IPMC flapping pectoral fins.

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Abstract:

Ionic polymer metal composites (IPMC) are a new class of smart materials that have attractive characteristics such as muscle like softness, low voltage and power consumption, and good performance in aqueous environments. Therefore, there is a significant motivation for research on design and development of IPMC based biomimetic propulsion systems for underwater vehicles. In aerospace, underwater vehicles finds application for forensic studies of spaceship wrecks, missile fragments and any airplane accidents in sea and ocean terrains. Such vehicles can also survey moons and planets that house water oceans. Among biomimetic swimming systems, fish inspired swimming has gained interest since fish like swimming provides high maneuverability, high cruising speed, noiseless propulsion and efficient stabilization compared to conventional propulsion systems. In this work, the paired pectoral fin based oscillatory propulsion using IPMC for aquatic propulsor applications is studied. Dynamic characteristics of IPMC fin are analyzed using numerical simulations and optimization is used to improve the fin design. A complex hydrodynamic function is used to describe the behavior of an active IPMC fin actuator in water. The structural model of the IPMC fin is obtained by modifying the classical dynamic equation for a slender beam to account for the electromechanical dynamics of the IPMC beam in water. A quasi-steady blade element model that accounts for unsteady phenomena such as added mass effects, dynamic stall, and the cumulative Wagner effect is used to estimate the hydrodynamic performance of the flapping fin. It is shown that the use of optimization methods can lead to significant improvement in performance of the IPMC fin. Further, three fish species with high performance flapping pectoral fin locomotion are chosen and performance analysis of each fin design is conducted to discover the better configurations for engineering applications. Dynamic characteristics of IPMC actuated flapping fins having the same size as the actual fins of three different fish species, Gomphosus varius, Scarus frenatus and Sthethojulis trilineata, are also analyzed. Finally, a comparative study is performed to analyze the performance of the three different biomimetic IPMC flapping pectoral fins.

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Οι τεχνολογίες κατανεμημένου υπολογισμού, όπως τα δίκτυα πλέγματος και οι υποδομές Νέφους, έχουν διαμορφώσει πλέον ένα καινούργιο περιβάλλον σχετικά με τον τρόπο που εκτελούνται οι εργασίες των χρηστών, αποθηκεύονται τα δεδομένα και γενικότερα χρησιμοποιούνται οι εφαρμογές. Τα δίκτυα πλέγματος αποτέλεσαν το επίκεντρο της σχετικής ερευνητικής δραστηριότητας για μεγάλο χρονικό διάστημα, με βασικό στόχο τη δημιουργία υποδομών για την εκτέλεση ερευνητικών εφαρμογών με πολύ υψηλές υπολογιστικές και αποθηκευτικές απαιτήσεις. Ωστόσο είναι πλέον προφανές ότι υπάρχει μια στροφή προς τις υποδομές Νέφους που προσφέρουν υπηρεσίες κατανεμημένου υπολογισμού και αποθήκευσης μέσω πλήρως διαχειρίσιμων πόρων. Η συγκεκριμένη μετάβαση έχει ως αποτέλεσμα μια μετατόπιση από το μοντέλο των πολλών και ισχυρών πόρων που βρίσκονται κατανεμημένοι σε διάφορες περιοχές του κόσμου (όπως στα δίκτυα πλέγματος) προς σχετικά λιγότερα αλλά πολύ μεγαλύτερα ως προς το μέγεθος κέντρα δεδομένων τα οποία αποτελούνται από χιλιάδες υπολογιστικούς πόρους οι οποίοι φιλοξενούν ακόμη περισσότερες εικονικές μηχανές.Η έρευνα που διεξάγαμε ακολούθησε αυτή την αλλαγή, μελετώντας αλγοριθμικά θέματα για δίκτυα πλέγματος και υποδομές Νεφών και αναπτύσσοντας μια σειρά από εργαλεία και εφαρμογές που διαχειρίζονται, παρακολουθούν και αξιοποιούν τους πόρους που προσφέρουν οι συγκεκριμένες υποδομές.Αρχικά, μελετούμε τα ζητήματα που προκύπτουν κατά την υλοποίηση αλγορίθμων χρονοπρογραμματισμού, που είχαν προηγουμένως μελετηθεί σε περιβάλλοντα προσομοίωσης, σε ένα πραγματικό σύστημα ενδιάμεσου λογισμικού για δίκτυα πλέγματος, και συγκεκριμένα το gLite. Το πρώτο ζήτημα που αντιμετωπίσαμε είναι το γεγονός ότι οι πληροφορίες που παρέχει το ενδιάμεσο λογισμικό gLite στους αλγορίθμους χρονοπρογραμματισμού δεν είναι πάντα έγκυρες, γεγονός που επηρεάζει την αποδοσή τους. Για την αντιμετώπιση του προβλήματος αναπτύξαμε ένα εσωτερικό, στο χρονοπρογραμματιστή, μηχανισμό που καταγράφει τις αποφάσεις του σχετικά με ποιές εργασίες ανατέθηκαν σε ποιούς υπολογιστικούς πόρους και λειτουργεί συµπληρωµατικά µε την υπηρεσία πληροφοριών του gLite. Επιπλέον, εξετάζουμε το ζήτημα του δίκαιου διαμοιρασμού της υπολογιστικής χωρητικότητας ενός πόρου στις εργασίες που έχουν ανατεθεί σε αυτόν. Για το σκοπό αυτό, επεκτείνουμε το ενδιάμεσο λογισμικό gLite ώστε να περιλαμβάνει ένα νέο μηχανισμό που μέσω της αξιοποίησης της τεχνολογίας εικονικοποίησης επιτρέπει τον ταυτόχρονο διαμοιρασμό της υπολογιστικής χωρητικότητας ενός κόμβου σε πολλές εργασίες.Στην συνέχεια εξατάζουμε το πρόβλημα της συνδυασμένης μεταφοράς πολλαπλών εικονικών μηχανών σε σύγχρονες υπολογιστικές υποδομές. Πιο συγκεκριμένα, προτείνουμε μια μεθοδολογία που στοχεύει στην καλύτερη χρησιμοποίηση των διαθέσιμων υπολογιστικών και δικτυακών πόρων, λαμβάνοντας υπόψη στις αποφάσεις σχετικά με τη συνδυασμένη μεταφορά εικονικών μηχανών τις αλληλεξαρτήσεις που δημιουργούνται από την επικοινωνία τους. Η προτεινόμενη μεθοδολογία χρησιμοποιεί την προσέγγιση πολλαπλών κριτηρίων για την επιλογή των εικονικών μηχανών που θα μετακινηθούν, αναθέτοντας διαφορετικά βάρη στα διάφορα κριτήρια ενδιαφέροντος. Επιπλέον, επιλέγει τους υπολογιστικούς κόμβους όπου οι μετακινούμενες εικονικές μηχανές θα φιλοξενηθούν, λαμβάνοντας υπόψη τον τρόπο με τον οποίο οι μετακινήσεις επηρεάζουν τις λογικές (ή εικονικές) τοπολογίες που σχηματίζονται από την επικοινωνία τους και αντιμετωπίζοντας τη συγκεκριμένη επιλογή ως ένα πρόβλημα αναδιάρθρωσης λογικών τοπολογιών. Η αξιολόγηση επιβεβαίωσε τη δυνατότητα της μεθοδολογίας να επιλύει, μέσω των κατάλληλων μετακινήσεων, ένα σημαντικό αριθμό προβλημάτων που οφείλονται σε ελλείψεις υπολογιστικών ή επικοινωνιακών πόρων, ελαχιστοποιώντας παράλληλα τον αριθμό των μετακινήσεων και την προκαλούμενη επιβάρυνση του δικτύου.Το επόμενο θέμα που εξετάζουμε αφορά το πρόβλημα της ανάλυσης δεδομένων επικοινωνίας μεταξύ εικονικών μηχανών οι οποίες φιλοξενούνται σε ένα κέντρο δεδομένων. Προτείνουμε και αξιολογούμε, μέσω της ανάλυσης δεδομένων από ένα πραγματικό κέντρο δεδομένων, την εφαρμογή μετρικών και τεχνικών από τη θεωρία ανάλυσης κοινωνικών δικτύων για τον προσδιορισμό σημαντικών εικονικών μηχανών, για παράδειγμα εικονικές μηχανές οι οποίες απαιτούν περισσότερο εύρος ζώνης σε σχέση με άλλες, και ομάδων εικονικών μηχανών που συσχετίζονται με κάποιο τρόπο μεταξύ τους. Μέσω της συγκεκριμένης προσέγγισης έχουμε τη δυνατότητα να εξάγουμε σημαντικές πληροφορίες οι οποίες μπορούν να αξιοποιηθούν για τη λήψη καλύτερων αποφάσεων σχετικά με τη διαχείριση του πολύ μεγάλου πλήθους των εικονικών μηχανών που φιλοξενούνται στα σύγχρονα κέντρα δεδομένων.Στη συνέχεια προσδιορίζουμε τρόπους με τους οποίους οι πληροφορίες παρακολούθησης που συλλέγονται από τη λειτουργία μιας δημόσιας υποδομής Υπολογιστικού Νέφους, και ιδίως από την υπηρεσία Amazon Web Services (AWS), μπορούν να χρησιμοποιηθούν με ένα αποδοτικό τρόπο προκειμένου να εξάγουμε πολύτιμες πληροφορίες, που μπορούν να αξιοποιηθούν από τους τελικούς χρήστες για την αποτελεσματικότερη διαχείριση των εικονικών πόρων τους. Πιο συγκεκριμένα, παρουσιάζουμε το σχεδιασμό και την υλοποίηση ενός εργαλείου ανοιχτού κώδικα, του SuMo, στο όποιο έχουμε υλοποίησει όλη την απαραίτητη λειτουργικότητα για τη συλλογή και ανάλυση δεδομένων παρακολούθησης από την υπηρεσία AWS. Επιπλέον, προτείνουμε ένα μηχανισμό για τη βελτιστοποίηση του κόστους και της αξιοποίησης (Cost and Utilization Optimization - CUO) των εικονικών υπολογιστικών πόρων της υπηρεσίας AWS. Ο μηχανισμός CUO χρησιμοποιεί πληροφορίες (πλήθος, ακριβή χαρακτηριστικά, ποσοστό αξιοποίησης) για τους διαθέσιμους εικονικούς πόρους ενός χρήστη και προτείνει ένα νέο (βέλτιστο) σύνολο πόρων που θα μπορούσαν να χρησιμοποιηθούν για την αποδοτικότερη εξυπηρέτηση του ίδιου φορτίου εργασίας με μειωμένο κόστος. Τέλος, παρουσιάζουμε την υλοποίηση ενός ολοκληρωμένου εργαλείου, που ονομάζουμε Mantis, για το σχεδιασμό και τη λειτουργία των μελλοντικών ευέλικτων (flex-grid) οπτικών δικτύων που υποστηρίζει επιπλέον οπτικά δίκτυα σταθερού πλέγματος τόσο μοναδικού ρυθμού μετάδοσης όσο και πολλαπλών ρυθμών μετάδοσης. Οι χρήστες έχουν τη δυνατότητα να καθορίζουν δικτυακές τοπολογίες, απαιτήσεις κίνησης, παραμέτρους για το κόστος απόκτησης και λειτουργίας των δικτυακών συσκευών, ενώ επιπλέον έχουν πρόσβαση σε αρκετούς αλγορίθμους για το σχεδιασμό, λειτουργία και αξιολόγηση διαφόρων οπτικών δικτύων. Το εργαλείο έχει σχεδιαστεί ώστε να μπορεί να λειτουργεί είτε ως υπηρεσία (Software as a Service) είτε ως κλασσική εφαρμογή (Desktop Application). Λειτουργώντας ως υπηρεσία παρέχει κλιμάκωση με βάση τις απαιτήσεις των χρηστών, αξιοποιώντας τα πλεονεκτήματα των υποδομών Υπολογιστικού Νέφους, εκτελώντας γρήγορα και αποτελεσματικά τις εργασίες των χρηστών. Για τη λειτουργία αυτή, μπορεί να χρησιμοποιεί τόσο δημόσιες υποδομές Υπολογιστικού Νέφους όπως η υπηρεσία Amazon Web Services (AWS) και η υπηρεσία της ΕΔΕΤ (~okeanos), όσο και ιδιωτικές που βασίζονται στο OpenStack. Επιπλέον, η αρθρωτή αρχιτεκτονική και η υλοποίηση των διαφόρων λειτουργικών τμημάτων επιτρέπουν την εύκολη επέκταση του εργαλείου ώστε να υποστηρίζει μελλοντικά περισσότερες υποδομές Υπολογιστικού Νέφους.
Distributed computing technologies, like grids and clouds, shape today a new environment, regarding the way tasks are executed, data are stored and retrieved, and applications are used. Though grids and desktop grids have been the focus of the research community for a long time, a shift has become evident today towards cloud and virtualization related technologies in general, which are supported by large computing factories, namely the data centers. As a result there is also a shift from the model of several powerful resources distributed at various locations in the world (as in grids) towards fewer huge data centers consisting of thousands of “simple” computers that host Virtual Machines.The research performed over the course of my PhD followed this shift, investigating algorithmic issues in the context of grids and then of clouds and developing a number of tools and applications that manage, monitor and utilize these kinds of resources. Initially, we describe the steps followed, the difficulties encountered, and the solutions provided in developing and evaluating a scheduling policy, initially implemented in a simulation environment, in the gLite grid middleware. Our focus is on a scheduling algorithm that allocates in a fair way the available resources among the requested users or jobs. During the actual implementation of this algorithm in gLite, we observed that the validity of the information used by the scheduler for its decisions affects greatly its performance. To improve the accuracy of this information, we developed an internal feedback mechanism that operates along with the scheduling algorithm. Also, a Grid computation resource cannot be shared concurrently between different users or jobs, making it difficult to provide actual fairness. For this reason we investigated the use of virtualization technology in the gLite middleware. We implement and evaluate our scheduling algorithm and the proposed mechanisms in a small gLite testbed.Next, we present a methodology, called communication-aware virtual infrastructures (COMAVI), for the concurrent migration of multiple Virtual Machines (VMs) in computing infrastructures, which aims at the optimum use of the available computational and network resources, by capturing the interdependencies between the communicating VMs. This methodology uses multiple criteria for selecting the VMs that will migrate, with different weights assigned to each of them. COMAVI also selects the computing sites where the migrating VMs will be hosted, by accounting for the way migration affects the logical (or virtual) topologies formed by the communicating VMs and viewing this selection as a logical topology reconfiguration problem. We apply COMAVI to two basic computing infrastructures that exhibit different constraints/criteria and characteristics: a grid infrastructure operating over a wide area network (WAN) and a data center infrastructure operating over a local area network (LAN). Through the presented methodology different communication-aware VM migration algorithms can be tailored to the needs of the resource provider. The algorithms presented resolve the maximum possible number of VM violations (due to computing or communication resource shortages), while tending to minimize the number of migrations performed, the induced network overhead, the logical topology reconfigurations required, and the corresponding service interruptions. We evaluate the proposed methods through simulations in realistic computing environments, and we exhibit their performance benefits.We also consider the use of social network analysis methods on communication traces, collected from Virtual Machines (VMs) located in computing infrastructures, like a data center. Our aim is to identify important VMs, for example VMs that require more bandwidth than other VMs or VMs that communicate often with other VMs. We believe that this approach can handle the large number of VMs present in computing infrastructures and their interactions in the same way social interactions of millions of people are analyzed in today’s social networks. We are interested in identifying measures that can locate these important VMs or groups of interacting VMs, missed through other usual metrics and also capture the time-dynamicity of their interactions. In our work we use real traces and evaluate the applicability of the considered methods and measures.In addition, we consider the analysis and optimization of public clouds. For this reason, we identify important algorithmic operations that should be part of a cloud analysis and optimization tool, including resource profiling, performance spike detection and prediction, resource resizing, and others, and we investigate ways in which the collected monitoring information can be processed towards these purposes. The analyzed information is valuable since it can drive important virtual resource management decisions. We also present an open-source tool we developed, called SuMo, which contains the necessary functionalities for collecting monitoring data from Amazon Web Services (AWS), analyzing them and providing resource optimization suggestions. We also present a Cost and Utilization Optimization (CUO) mechanism for optimizing the cost and the utilization of a set of running Amazon EC2 instances, which is formulated as an Integer Linear Programming (ILP) problem. This CUO mechanism receives information regarding the current set of instances used (their number, type, utilization) and proposes a new set of instances for serving the same load, so as to minimize cost and maximize utilization and performance efficiency.Finally, we present a network planning and operation tool, called Mantis, for designing the next generation optical networks, supporting both flexible and mixed line rate WDM networks. Through Mantis, the user is able to define the network topology, current and forecasted traffic matrices, CAPEX/OPEX parameters, set up basic configuration parameters, and use a library of algorithms to plan, operate, or run what-if scenarios for an optical network of interest. Mantis is designed to be deployed either as a cloud service or as a desktop application. Using the cloud infrastructures features Mantis can scale according to the user demands, executing fast and efficiently the scenarios requested. Mantis supports different cloud platforms either public such as Amazon Elastic Compute Cloud (Amazon EC2) and ~okeanos the GRNET’s cloud service or private based on OpenStack, while its modular architecture allows other cloud infrastructures to be adopted in the future with minimum effort.