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Nguyen, Bich-Châu. "Control-Rod Guide Tube wear inspection: implementation of the surveillance". Thesis, KTH, Fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103269.
Pełny tekst źródłaBernardi, Pierre. "Utilisation et Amélioration du Modèle Discret d'Excitation d'un Guide d'Onde Périodique pour la Simulation Pratique du Tube à Onde Progressive en Domaine Temporel". Phd thesis, Université de Provence - Aix-Marseille I, 2011. http://tel.archives-ouvertes.fr/tel-00708349.
Pełny tekst źródłaNekvapil, Jan. "Vliv optických prvků na účinnost světlovodu". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-318498.
Pełny tekst źródłaBessard, Gilles. "Caractérisation de matériaux de découplage à l'aide d'un tube à ondes progressives". Valenciennes, 1995. https://ged.uphf.fr/nuxeo/site/esupversions/e4a4a16f-0fa8-410d-80df-f3a641cf6b61.
Pełny tekst źródłaGeulin, Eléonore. "Contribution to the modeling of pellet injection : from the injector to ablation in the plasma". Electronic Thesis or Diss., Aix-Marseille, 2023. http://www.theses.fr/2023AIXM0066.
Pełny tekst źródłaThe preferred method of fueling fusion device is the use of D and/or T pellets injected into the plasma. They are currently used, but the results cannot be extrapolated to future larger reactors where the design of the injection system and the construction of scenarios will be mainly based on simulations. It is therefore important to fill in the gaps in the existing models from the manufacture of pellets to the deposition of material in the plasma. Two lacks of knowledge appear: the modeling of the pellet transport in the injection pipe and the validation of the ablation process. This work aims to fill these gaps and consists of 3 parts.- Describe the physics of material deposition, then the state of the art of the main results and finally the description of the pellet injection systems planned for the next machines.- Model the transport of the pellet in the injection pipe. The effects taken into account in the model are the weakening of the ice during rebounds, the increase in its temperature and its erosion. The model gives in particular the slowing down and the loss of mass of the pellet during the journey, as well as the stored elastic energy linked to its integrity on leaving the tube.- Contribute to the validation of the HPI2 ablation code, by comparing its predictions to data measured in ablation clouds. The method used is a calculation of synthetic data sets from simulations and comparing them to measurements. This method made it possible to validate the assumptions and approximations of the ablation model
Trdak, Kresimir. "Intensités vibratoire et acoustique dans les tuyaux". Phd thesis, Université de Technologie de Compiègne, 1995. http://tel.archives-ouvertes.fr/tel-00424848.
Pełny tekst źródłaAl-Ayoubi, Samer. "Guide tubes for ultracold neutrons". Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344066.
Pełny tekst źródłaKaspar, Lucas J. "The Bass Trombonist's Guide to the Tuba Repertoire". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu153193743404808.
Pełny tekst źródłaDaniels, Barret R. "Magnetic Resonance Guided Nasojejunal Feeding Tube Placement for Neonates". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439281638.
Pełny tekst źródłaRobinson, Ryan J. "A Performance Guide for the Unique Challenges in Concerto for Tuba and Chamber Orchestra by Jan Bach". Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc699963/.
Pełny tekst źródłaРябова, Світлана Олександрівна. "Гідродинамічне удосконалення поворотно-лопатевої гідротурбіни на основі використання просторового профілювання лопатей робочого колеса". Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/29700.
Pełny tekst źródłaThe dissertation for the degree of Candidate of Technical Sciences in the specialty 05.05.17 – hydraulic machines and hydropneumatic units. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2017. The thesis is devoted to solving of important scientific and technical problem of improving the energy characteristics of the flow part of Kaplan turbine. A review of the scientific and technical literatures on the methods of testing of hydrodynamic processes in flow parts of the Kaplan turbines has been carried out. According to the results of numerical investigations of the spatial flow of a viscous incompressible fluid in the flow part of the Kaplan turbine PL 20/3271у of the Kremenchug HPP detailed information on the structure of flow in all elements of the flow part in a wide range of operating modes has been received using software complex IPMflow developed at IPMash NAS of Ukraine. The influence of flow parameters at the inlet to the computational domain on the characteristics of the flow part has been investigated, a range of operation modes of Kaplan turbine that provide uniform distribution of the hydrodynamic values in circular direction at the inlet to the runner has been established. The approach to spatial profiling of the runner blades of Kaplan turbines based on the use of complex offsets in the axial and circular directions, which allows improving the energy characteristics of a flow part has been proposed. The influence of complex axial and circular offsets of the runners on flow structure and integral energy parameters that can be used in the design and modernization of the flow parts of Kaplan turbines have been established. The runner with combined peripheral offset of the modern high-performance Kaplan turbine ПЛ20/3271у Kremenchug HPP with improved energy performance has been developed.
Рябова, Світлана Олександрівна. "Гідродинамічне удосконалення поворотно-лопатевої гідротурбіни на основі використання просторового профілювання лопатей робочого колеса". Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/29696.
Pełny tekst źródłaThe dissertation for the degree of Candidate of Technical Sciences in the specialty 05.05.17 – hydraulic machines and hydropneumatic units. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2017. The thesis is devoted to solving of important scientific and technical problem of improving the energy characteristics of the flow part of Kaplan turbine. A review of the scientific and technical literatures on the methods of testing of hydrodynamic processes in flow parts of the Kaplan turbines has been carried out. According to the results of numerical investigations of the spatial flow of a viscous incompressible fluid in the flow part of the Kaplan turbine PL 20/3271у of the Kremenchug HPP detailed information on the structure of flow in all elements of the flow part in a wide range of operating modes has been received using software complex IPMflow developed at IPMash NAS of Ukraine. The influence of flow parameters at the inlet to the computational domain on the characteristics of the flow part has been investigated, a range of operation modes of Kaplan turbine that provide uniform distribution of the hydrodynamic values in circular direction at the inlet to the runner has been established. The approach to spatial profiling of the runner blades of Kaplan turbines based on the use of complex offsets in the axial and circular directions, which allows improving the energy characteristics of a flow part has been proposed. The influence of complex axial and circular offsets of the runners on flow structure and integral energy parameters that can be used in the design and modernization of the flow parts of Kaplan turbines have been established. The runner with combined peripheral offset of the modern high-performance Kaplan turbine ПЛ20/3271у Kremenchug HPP with improved energy performance has been developed.
Nguyen, Bich-Châu. "CONTROL-ROD GUIDE TUBES WEAR INSPECTION: IMPLEMENTATION OF THE SURVEILLANCE". Thesis, KTH, Fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174066.
Pełny tekst źródłaQuach, Lucian. "Application of gestural guided continuum robots in orthopaedic surgery". Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/208080/1/Lucian_Quach_Thesis.pdf.
Pełny tekst źródłaHynds, Aaron Michael. "The Composer's Guide to the Tuba: Creating a New Resource on the Capabilities of the Tuba Family". Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1558255903237631.
Pełny tekst źródłaMachová, Petra. "Denní osvětlení prostor světlovody". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240303.
Pełny tekst źródłaRamsay, Thomas A. "An analysis of component breakout for the Tube Launched Optically Tracted Wire-Guided Missile System". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA306657.
Pełny tekst źródłaThesis advisor(s): Mark W. Stone, John T. Dillard. "December 1995." Includes bibliographical references. Also available online.
Grosjean, Catherine. "Anisotropie de comportement en fluage thermique de tubes gaine et de tubes guide en alliages de Zirconium. Développements expérimentaux et résultats". Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT019G.
Pełny tekst źródłaFuel rods and cladding tubes in zirconium are essential structural parts of Pressurized Water Reactors. There are submitted in service to aggressive environment (vapour at ~320°C, 155 bars, and irradiation) and to multiaxial mechanical loadings leading to thermal creep which has to be quantified. The present work aims to determine the effects of 3 parameters on the mechanical behaviour of different zirconium alloys: the loading path, the metallurgical state (stress-relieved, recrystallized) and the chemical composition. The first step to take was to develop a new device adapted to different geometries of tubes, and to validate it by comparing experimental results obtained upon the stress-relieved Zircaloy 4 to bibliographical results. Second, a large database has been constituted on the M5® in order to highlight the effects of an overloading or of cycling on the circumferential stress, and of the loading path (application of the axial then the circumferential stress, or the contrary or proportional loading). Then by comparing the behaviour of the recrystallized and the stress-relieved Zircaloys 4, the effects of the metallurgical state on this hexagonal alloy on the creep behaviour have also been studied. Lastly, the effects of oxygen, stain and iron have been quantified due to 5 other alloys (M5® low and high oxygen, Q12, Q32 and Q42). The last step of this work corresponds to the model of the macroscopic behaviour of 2 alloys (M5® and Zircaloy 4) with isotropic and anisotropic criteria to prove the necessity of developing a new and strong model adapted to highly anisotropic alloys like Zirconium alloys
Atig, Merouane. "Non-linéarité acoustique localisée à l'extrémité ouverte d'un tube : mesure, modélisation et application aux instruments à vent". Le Mans, 2004. http://cyberdoc.univ-lemans.fr/theses/2004/2004LEMA1018.pdf.
Pełny tekst źródłaThe study deals with localised non-linear acoustic losses at the open end of a tube. Three aspects are considered : firstly, a description of the phenomenon by the measurement of the terminal Impedance of the tube, secondly, the physical modeling of the phenomenon and finally the application to woodwind instruments. In a first part,measurements of the terminal impedance using a two microphone method show that losses at the open end of the tube - real part of the terminalion impedance in the first harmonic approximation - increase with the acoustical velocity amplitude. Results show that the losses highly depend on the radius of curvature of the tube's inner edges. Moreover, for low values of the radius of curvature, two behaviours are observed. Particle image velocimetry (PIV) visualisations carried out at the University of Edinburgh confirm these two behaviours : in both cases, a vortex ring is created at the open end but it stays in the vicinity of the exit for low acoustical velocities whereas it is expelled for higher acoustical velocities. The second part deals with the physical modeling of the phenomena. The application of the vortex-sound theory allows a direct estimation of the losses at the open end. Three calculations using this theory are carried out. The first calculation is analylical and is based on a discrete vortex ring which can be either fixed or mobile; the second one cornes from PIV visualisations; and the third one is numerical, using the lattice Boltzmann method. The three calculations lead to similar results : non-linear losses find their origin in the formation of vortex rings at the end of the tube. These results are succesfully compared to impedance measurements. The third part analyses the influence of non-linear losses on the behaviour of a side-holed wind instrument. Experiments and simulations show that the playing range of a wind instrument depends on the losses in the instrument and that the playing range can be extended by reducing the non-linear losses at the open end
Atig, Merouane Dalmont Jean-Pierre Gilbert Joël. "Non-linéarité acoustique localisée à l'extrémité ouverte d'un tube mesure, modélisation et application aux instruments à vent /". [S.l.] : [s.n.], 2004. http://cyberdoc.univ-lemans.fr/theses/2004/2004LEMA1018.pdf.
Pełny tekst źródłaOaker, Bradley. "The detection of defects in tubes and plates using guided waves". Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11182.
Pełny tekst źródłaYucel, Deniz. "Stem Cell Based Nerve Tissue Engineering On Guided Constructs". Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610399/index.pdf.
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-Tubulin III whereas astrocytes expressed glial fibrillary acidic protein (GFAP), an astrocyte marker. RT-PCR showed that early neural markers, nestin and Nurr 1, were expressed at passage 4 by undifferentiated MSCs and by MSCs induced to neural differentiation, while these markers were not expressed in undifferentiated MSCs at passages 2 and 3. The cells aligned along the axis of the micropattern of the film and along the axis of the fiber on the fibrous mat. This behavior was also maintained after construct formation. MTS and confocal microscopy revealed that the cells were viable and homogeneously distributed over the two parts of the scaffold. This indicates that the construct has a potential to be tested in vivo for nerve tissue engineering purposes.
Yi, Chung-han. "A performance guide to Heejo Kim's choral arrangements based on traditional Korean folk tune and rhythmic patterns". connect to online resource, 2009. http://digital.library.unt.edu/permalink/meta-dc-9818.
Pełny tekst źródłaMograne, Mohamed Abderrahmane. "Viscosimétrie ultrasonore ultra large bande". Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS089/document.
Pełny tekst źródłaThe main goal of this thesis is to set specific piezoelectric elements emitting longitudinal waves (L) on a well-known container in the field of biomedical and chemistry (a test tube) and to implement with some optimizations various ultrasonic methods to measure viscosities quickly, without changing the measurement bench. The measurement has to be done from a few Hz to several tens of megahertz around room temperature. Up to now it is possible to determine in a few minutes the rheological behavior of the liquid studied thanks to the evaluation of its shear viscosity. Furthermore, the viscosity range reached is extremely wide: the measurements are possible from a few tens of mPa.s to several hundred Pa.s. Finally, beyond quantitative results in terms of viscosity, the measurement bench can also be used to qualitatively monitor reactions (polymerization for example)
Tignor, Scott Edward. "A Performance Guide to Luigi Nono's Post-Prae-Ludium No. 1 "Per Donau"". Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc11006/.
Pełny tekst źródłaBouvier, Yves. "Le drainage percutané guidé par imagerie des abcès abdominaux en pathologie digestive : de l'initiation à la réalisation en pratique courante". Montpellier 1, 1992. http://www.theses.fr/1992MON11104.
Pełny tekst źródłaWojda, Franck. "Mesure de l'amplitude d'une onde de plasma créée par sillage laser guidé". Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00485671.
Pełny tekst źródłaAtig, Mérouane. "Non-linéarité acoustique localisée à l'extrémité ouverte d'un tube. Mesure, modélisation et application aux instruments à vent". Phd thesis, Université du Maine, 2004. http://tel.archives-ouvertes.fr/tel-00009283.
Pełny tekst źródłaDans une première partie, des mesures de l'impédance terminale réalisées à l'aide d'une méthode à deux microphones montrent que les pertes à la sortie du tube - partie réelle de l'impédance terminale dans le cadre de l'approximation du premier harmonique - augmentent avec l'amplitude de la vitesse acoustique. Les résultats montrent que l'importance de ces pertes dépend fortement du rayon de courbure des bords intérieurs à la sortie de tube. En outre, pour les faibles rayons de courbure, deux régimes sont mis en évidence. L'existence de ces deux régimes est confirmée par des observations utilisant la vélocimétrie par imagerie de particules (PIV) réalisées en collaboration avec l'Université d'Edimbourg : dans les deux cas un anneau tourbillonnaire est formé à la sortie du tube mais dans le cas du premier régime (faibles vitesses acoustiques) l'anneau reste accroché aux bords du tube alors que dans le cas du second régime (fortes vitesses acoustiques) il est expulsé.
La seconde partie concerne la modélisation du phénomène dans le but de mieux comprendre les mécanismes physiques mis en jeu. La théorie du bruit tourbillonnaire (``vortex sound theory'') est appliquée afin d'estimer directement les pertes à la sortie du tube. Trois calculs utilisant cette théorie sont menés : le premier, analytique, sur la base d'un unique anneau tourbillonnaire fixe ou mobile, le second à partir des mesures par PIV et le troisième par la méthode numérique dite des réseaux de Boltzmann. Les trois calculs conduisent à des résultats similaires qui démontrent que les pertes non linéaires trouvent leur origine dans la formation d'anneaux tourbillonnaires en sortie de tube. Ces résultats sont confrontés avec succès aux résultats issus des mesures d'impédance.
La troisième partie analyse les conséquences que peuvent avoir les pertes non linéaires dans le fonctionnement d'un instrument de musique à trous latéraux. Il est montré expérimentalement et à l'aide de simulations numériques que la dynamique de jeu d'un instrument à vent dépend directement des pertes dans l'instrument et que cette dynamique peut être étendue lorsque les pertes à la sortie sont minimisées par exemple en chanfreinant les bords des trous latéraux.
Oldham, Jonathan Reed. "Development of a Multiple Microphone Probe Calibrator". Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2042.pdf.
Pełny tekst źródłaStowman, William J. (William John). "A Guide for the Preparation, Analysis and Performance of the Brass Quintet Literature of Thom Ritter George, with Three Recitals of Selected Works by Bach, Bitsch, Handel, Torelli, Suderberg, Ketting and Others". Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc935818/.
Pełny tekst źródłaBUENO, REGIS C. "Detecção de contornos em imagens de padrões de escoamento bifásico com alta fração de vazio em experimentos de circulação natural com o uso de processamento inteligente". reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26817.
Pełny tekst źródłaMade available in DSpace on 2016-11-11T13:03:47Z (GMT). No. of bitstreams: 0
Este trabalho desenvolveu um novo método para a detecção de contornos em imagens digitais que apresentam objetos de interesse muito próximos e que contêm complexidades associadas ao fundo da imagem como variação abrupta de intensidade e oscilação de iluminação. O método desenvolvido utiliza lógicafuzzy e desvio padrão da declividade (Desvio padrão da declividade fuzzy - FuzDec) para o processamento de imagens e detecção de contorno. A detecção de contornos é uma tarefa importante para estimar características de escoamento bifásico através da segmentação da imagem das bolhas para obtenção de parâmetros como a fração de vazio e diâmetro de bolhas. FuzDec foi aplicado em imagens de instabilidades de circulação natural adquiridas experimentalmente. A aquisição das imagens foi feita utilizando o Circuito de Circulação Natural (CCN) do Instituto de Pesquisas Energéticas e Nucleares (IPEN). Este circuito é completamente constituído de tubos de vidro, o que permite a visualização e imageamento do escoamento monofásico e bifásico nos ciclos de circulação natural sob baixa pressão.Os resultados mostraram que o detector proposto conseguiu melhorar a identificação do contorno eficientemente em comparação aos detectores de contorno clássicos, sem a necessidade de fazer uso de algoritmos de suavização e sem intervenção humana.
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IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Koussi, Erieta-Katerina. "Micro patterning of complex Waveguide Resonant Gratings (WRG)". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSES027.
Pełny tekst źródłaThis PhD thesis entitled “Micro patterning of complex Waveguide Resonant Gratings (WRG)” studies the optical sensing devices, which involve various photolithography techniques and nanotechnology tools with clean room processes for their fabrication. These devices, in their classic form, consist of a diffraction grating formed by microscopic lines engraved periodically on a photosensitive surface, which is deposited on a dielectric layer, the waveguide. Both layers are supported on a substrate. To enable sensing functions, the diffraction grating must be extremely selective, i.e. it must have the ability to reject all the received spectral components, while selecting only one wavelength to couple it into the waveguide. After the out coupling, a reflection with a very large amplitude and great finesse occurs. Different types of components depending on the intended application can be produced on different types of substrates, materials or geometries (plane, cylindrical).One of the projects of this thesis engineers WRG on the interior walls of a tube to couple TE and TM modes into the waveguide. The fabrication is achieved by a specially designed radial phase mask, whereas the optical function is highlighted by the use of a conical mirror, able to reflect light isotropically for mode excitation. In addition, innovative materials can be used for their integration into flat WRG. One of the materials under study is the Vanadium Dioxide (VO2), which undergoes first-order phase transitions (Insulator to Metal) at low and high temperatures respectively. The fabrication of such a delicate compound is completed by two different synthesis methods, the Pulsed Laser Deposition and Magnetron Sputtering. The ability to induce resonance by thermally triggering the device is intended for laser safety applications to avoid damage during overheating
Maréchal, Romain. "Modélisation par méthode mixte analytique-numérique de la matrice de diffusion d'un conduit traité de longueur finie avec tubes Herschel-Quincke intégrés : application à la réduction du bruit de soufflante". Compiègne, 2011. http://www.theses.fr/2011COMP1988.
Pełny tekst źródłaIn aeronautic industry, the efficiency of acoustic liners in bypass and inter-stage regions of the turbofan engine is reached the limit, especially at the Blade Passage Frequencies (BPF), due to the interaction between the fan blades and the struts. Then, pure tones are produced in the noise spectrum for all flight phases, in addition of acoustic liners, Herschel-Quincke (HQ) tubes provide an alternative to improve the attenuation at the BPF. These tubes are placed in the periphery of the main duct and produce phase differences between acoustic waves in the main duct and in the HO tubes in order to attenuate the transmitted acoustic power. A mixed numerical-analytical model was developed for the fast computation of the scattering matrix of a ring of HO tubes integrated in a finite length line wall circular duct. This technic takes into account the exact shape of HO tube and the possibility of a non uniform acoustic velocity at the interfaces between the main duct and the HO tube. This model also allows a study of HQ tube parameters with a time swing compared to a standard element method. Finally, the mixed model has no frequency limit
Mignot, Rémi. "Réalisation en guides d'ondes numériques stables d'un modèle acoustique réaliste pour la simulation en temps-réel d'instruments à vent". Phd thesis, Télécom ParisTech, 2009. http://tel.archives-ouvertes.fr/tel-00456997.
Pełny tekst źródłaKarpfinger, Florian. "Modelling borehole wave signatures in elastic and poroelastic media with spectral method". Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/2447.
Pełny tekst źródłaPinho, Ana Catarina da Silva. "Peripheral nerve regeneration – development and evaluation of biodegradable polymers guide-tube". Doctoral thesis, 2018. http://hdl.handle.net/10316/80428.
Pełny tekst źródłaThe main goal of this PhD work was the development and evaluation of novel nerve guide conduits based on biocompatible and biodegradable polymers for regenerative medicine, namely peripheral nerve regeneration. The injury of the peripheral nerves are a quite common, especially in the young male population due to accidental traumatic events. The degree of injury may vary, being the most severe cases associated with permanent disability. Since the last century, new strategies to improve peripheral nerve regeneration after injury have been studied. The first technique proposed and still nowadays showing the best results is the use of nerve autograph. Nevertheless, this technique is associated to some disadvantages, which include the need of two surgeries and site morbidity. In this sense, nerve guide conduits, which consist in hollow tubes that are sutured to both nerve ends have been proposed as alternative. These conduits should guide the newly formed axons to the opposite nerve stump while providing a suitable environment for the enhancement of axon regeneration. Among several materials tested for the preparation of these devices, polymers have presented the most promising results. However, a device, which could reproduce results comparable to nerve autograph with suitable degradation ratio in vivo remains to be developed. In an attempt to overcome these limitations, the present work involved the use of the polysaccharide dextran as core material in the preparation of nerve guide conduits. The choice of this polymer relies on its well stablished biocompatibility and biodegradability. In addition, dextran is frequently reported for biomedical applications, being approved by the US Food and Drug Administration (FDA). The initial work undertaken aimed to modify the chemical structure of dextran by the incorporation of double bonds in its chains, for further crosslinking. In this sense, dextrans with different molecular weights were modified with two different monomers, Glycidyl methacrylate (GMA) and 2-Isocyanatoethyl methacrylate (IEMA). Circular transparent membranes were prepared by ultraviolet (UV)-photocrosslinking and the physico-chemical characteristics of the resulting products were evaluated. After the washing and drying stages, the final membranes presented a fragile structure. For this reason, a poly (ε-caprolactone) (PCL) macromonomer modified with IEMA was added to the membrane formulations. As a result, the flexibility of the membranes increased considerably. Additionally, the incorporation of PCL_IEMA did not affect the thermal-mechanical properties. On the other hand, the swelling capacity and in vitro degradation ratio decreased. The work continued with the evaluation of the cytotoxicity of the most promising membranes, using human dental pulp stem cells (hDPSCs). The intracellular concentration of the calcium ion was also measured after the cell viability test. All membranes were considered suitable substrates for cell adhesion and proliferation based on their morphology and healthy calcium ion concentration, suggesting the absence of any apoptosis process. Considering the promising results obtained, the next step focused on the evaluation of the extension of immune response due to implantation of the membranes in rats dorsum. After 15 days of implantation, membranes prepared with dextran modified with GMA and PCL derivative caused an immune response that was classified as “non-irritant”, by the scoring system of the standard ISO 10-998-6. After the relevant results obtained for the prepared materials in a membrane shape, the next step of the work was to achieve the tube conformation. In this regard, molds composed by a quartz tube with an internal 316L stainless steel rod, and with different dimensions were prepared. In order to tailor the final dimensions of the prepared tubes, shrinkage studies were conducted. The formulation, which presented the final dimensions more similar to the commercial product Neurolac®, was then chosen for the further characterization. The structures revealed to be very compact, showing no porosity. For this reason, in order to enhance permeability, D-mannitol was added to the formulations, as porogenic agent, to create voids in the structure of the tubes. The obtained pores presented a mean size in the range between 10-20μm. Posteriorly, the physico-chemical properties of the normal tube and porous tube were evaluated. With the incorporation of D-mannitol, the swelling capacity of the tubes decreased, which may be related to a lower crosslinking density. Moreover, for the porous structure, the in vitro degradation ratio increased, as expected, since the contact surface area also increases. Furthermore, after six months under in vitro hydrolytic tests, both tube structures were able to maintain their structural integrity. The mechanical properties of the tubes were evaluated by performing tensile tests, which revealed that both tubes have the ability to support tension and elongation forces slightly higher than the ones reported for the rat sciatic nerve. It is noteworthy to state that the tubes also were able to resist to preliminary suture tests without visible fragmentation. Finally, nerve guide conduits were tested in the rat sciatic nerve after a neurotmesis injury, for 20 weeks. The functional evaluation results showed that the recovery percentage of motor function is similar for both tubes. In what concerns the sensorial function, the rat group, which received the porous tube revealed higher percentage of recovery. In this sense, porosity seems to induce a positive effect on nerve regeneration. To sum up, this PhD work allowed the validation of dextran as core material for the preparation of nerve guide conduits for peripheral nerve regeneration. The obtained materials present a set of characteristics and properties, which may be relevant for the regeneration process. Furthermore, the fine-tuning of these properties can be easily achieved by changing the formulations used to prepare the tubes.
O principal objetivo deste trabalho de doutoramento consistiu no desenvolvimento e avaliação de novos tubos guia preparados a partir polímeros biocompatíveis e biodegradáveis, com aplicação em medicina regenerativa, nomeadamente regeneração de nervos do sistema nervoso periférico. As lesões de nervo periférico são bastante comuns, sendo que as principais causas de incidência desta patologia estão associadas à população jovem masculina, por ocorrência de eventos traumáticos acidentais. A severidade destas lesões varia bastante, no entanto, nos casos mais graves, pode mesmo resultar em incapacidade nervosa permanente. Por este motivo, ao longo do último século têm sido estudadas novas formas de melhorar a regeneração de nervo periférico após uma lesão. A utilização da técnica do autoenxerto revelou ser apresenta resultados mais satisfatórios, provando melhorar a qualidade do nervo regenerado. Contudo, esta técnica implica o recurso a duas cirurgias. Na perspetiva de evitar esta desvantagem, surge o conceito de tubo guia que consiste num tubo oco cuja principal função é fornecer um meio adequado à regeneração do novo nervo guiando o seu crescimento até à extremidade oposta. Nos últimos anos vários materiais têm sido utilizados na preparação destes dispositivos, sendo os materiais poliméricos aqueles que melhores resultados produziram. Porém, ainda não foi desenvolvida uma solução comparável à técnica de autoenxerto com um tempo de degradação in vivo que acompanhe o crescimento do nervo. No sentido de dar resposta a estas limitações, este trabalho envolve a utilização do polissacarídeo dextrano para a preparação de tubos guia. Este polímero foi escolhido como material base devido à sua biocompatibilidade e biodegradabilidade. Com efeito, o dextrano é recorrentemente reportado para aplicações biomédicas, sendo aprovado pela “US Food and Drug Administration” (FDA). Numa fase inicial do trabalho pretendeu-se modificar a estrutura química do dextrano, através da incorporação de ligações duplas nas suas cadeias, para posterior reticulação. Assim, dextrano de pesos moleculares diferentes foi modificado com dois monómeros diferentes, metacrilato de glicidilo (GMA) e metacrilato de 2-isocianoetilo (IEMA). Seguidamente, membranas circulares transparentes foram preparadas através da reticulação das cadeias dos materiais preparados, por radiação ultravioleta (UV). As suas características físico-químicas foram posteriormente avaliadas. Devido à fragilidade demonstrada por estas membranas, foi adicionado às formulações iniciais um macro monómero de base poli (ε-caprolactona) (PCL) modificado com IEMA. Como resultado, as membranas preparadas com dextrano modificado juntamente com o co monómero revelaram maior flexibilidade comparativamente às membranas previamente preparadas. Com a incorporação deste macro monómero verificou-se uma diminuição na capacidade de inchaço e da velocidade de degradação in vitro, não prejudicando, contudo, as propriedades térmo-mecânicas das membranas. O trabalho prosseguiu com a avaliação da citotoxicidade das membranas que apresentaram propriedades mais apropriadas para a aplicação em questão, com recurso a células da polpa dentária humana (hDPSC). A concentração do ião cálcio intracelular foi medida para atestar a viabilidade celular das células aderidas às membranas. Todas as membranas mostraram ser substratos apropriados para a adesão e proliferação celular, sugerindo a ausência de início do processo apoptótico. Seguidamente foi avaliada a extensão da reação imunológica provocada pela implantação subcutânea destas membranas no dorso de ratos. Neste caso, as membranas preparadas com dextrano modificado com GMA, e com a adição de PCL modificado com IEMA provocaram uma resposta imunológica, ao fim de 15 dias, que foi classificada de “não irritante”, através do sistema de pontuação proposto pela norma ISO 10-998-6. Face aos resultados relevantes, a etapa seguinte do trabalho consistiu na preparação de um tubo, utilizando as melhoras formulações de membranas. Neste sentido, foi preparado um molde de quartzo com uma vara de aço inoxidável 316L por forma a criar tubos ocos. Os moldes foram preparados com vista à obtenção de dimensões finais semelhantes às do produto comercial Neurolac®. Foram conduzidos estudos para avaliar o encolhimento das estruturas tubulares, permitindo assim a escolha da formulação mais adequada. Através de microscopia electrónica de varrimento (SEM) foi possível avaliação a superfície dos tubos, que se revelou ser bastante compacta. Neste sentido, foi adicionado D-Mannitol como agente porogénico, de modo que aumentar a permeabilidade dos tubos, por meio de indução de porosidade. Com recurso a esta técnica foi possível obter porosidade com tamanho médio compreendido entre 10-20µm. Posteriormente foi feito um estudo comparativo das propriedades físico-químicas do tubo sem porosidade e com porosidade. Com a introdução do D-mannitol, a capacidade de inchamento dos tubos diminuiu, o que pode denotar uma estrutura com menor densidade de reticulação. No entanto, com a porosidade, a velocidade de degradação dos tubos aumentou, como seria de esperar, visto que a superfície de contacto com o meio também é superior. Contudo, ao fim de seis meses, em solução de PBS os dois tubos mantiveram a sua integridade estrutural. As propriedades mecânicas destes tubos foram também avaliadas através de ensaios de tração uniaxial. Estes testes revelaram que os tubos têm capacidade de resistir a forças de tensão e elongação ligeiramente superiores às do nervo ciático de rato. De notar que estes tubos revelaram ser resistentes a testes preliminares de perfuração com sutura, sem fragmentação visível. Finalmente, os tubos guia foram testados em nervos ciáticos de ratos, após uma lesão de neurotmese induzida. Ao longo de 20 semanas os resultados da avaliação funcional do nervo lesionado mostram que em termos de função motora, a recuperação é semelhante para o tubo não poroso e para o tubo poroso. No que concerne a função sensorial, o grupo de ratos que recebeu o tubo poroso mostrou maior índice de recuperação. Assim, a porosidade aparenta ter um efeito positivo na regeneração do nervo. Este trabalho permitiu validar o dextrano como material base para a preparação de tubos-guia para a regeneração de nervo periférico. Os materiais obtidos apresentam um conjunto de características e propriedades relevantes para o processo regenerativo. Com efeito, estas podem ainda ser facilmente adaptadas através da alteração das formulações utilizadas para preparar os tubos.
Fundação para a Ciência e Tecnologia (FCT) - bolsa de doutoramento PD/BD/52626/2014
Sumathy, M. "Analysis Of Broad-band And High-Efficiency Folded-Waveguide Slow-Wave Structure For Millimeter-Wave Traveling-Wave Tubes". Thesis, 2011. https://etd.iisc.ac.in/handle/2005/2372.
Pełny tekst źródłaSumathy, M. "Analysis Of Broad-band And High-Efficiency Folded-Waveguide Slow-Wave Structure For Millimeter-Wave Traveling-Wave Tubes". Thesis, 2011. http://hdl.handle.net/2005/2372.
Pełny tekst źródłaRichard-Tremblay, Audrey-Ann. "La prise d’acide folique en période périconceptionnelle : une étude sur la concordance aux directives cliniques canadiennes et sur l’impact sur la prévalence des malformations congénitales au Québec". Thèse, 2012. http://hdl.handle.net/1866/9171.
Pełny tekst źródłaThe use of folic acid during the preconceptionnal period reduces the risk of neural tube defects (NTD), a malformation of the nervous system. In order to reduce it’s prevalence, the Society of Obstetricians and Gynaecologists of Canada proposed new practice clinical guidelines, in 2007, on the use of pre-conceptional vitamin/folic acid supplementation for the prevention of NTDs, with specific recommendations to prevent recurrences and occurrences among women with intermediate to high health risk factors and for whom the dose was different. The objectives of this study were to evaluate the concordance between the new guidelines and folic acid use in real life; 2) to identify predictors associated with a recommended folic acid supplementation, and 3) to evaluate if the use of folic acid could reduce the risk of congenital malformations other than NTDs. A cross-sectional study and an ecological study have been conducted. 361 women were recruited in obstetrics outpatient clinic at the CHU Ste-Justine for the first study and 152,392 pregnancies and babies were identified in the Quebec Pregnancy Registry, which results from the linkage of three administrative health care databases from Quebec (RAMQ, Med-Echo and ISQ) for the second study. Only 27% of the wowen recruited for the first study had periconceptional folic acid supplementation intake that was concordant with guideline. Concordance varied according to their health risk factors profile for NTD. Our ecological study showed that the annual prevalence of periconceptional folic acid use increased from 0.17% to 0.80% (p < 0,0001) from 1998 to 2008 and birth prevalence of major congenital malformations increased by 15% (3.35% to 3.87%, p < 0,0001) during the same period. Our findings highlight the fact that folic acid is not widely used by women of childbearing age, regardless of the dose. There is a need for new public health programs to encourange women to consume folic acid every day before and during pregnancy. Moreover, the use of high dose folic acid does not seem to be correlated with a decline in the prevalence of major congenital malformations, on a populational level.
Lou, Ton Shun, i 駱東春. "Guides Waves in Circular Cylindrical Tubes". Thesis, 1994. http://ndltd.ncl.edu.tw/handle/81726988249304491718.
Pełny tekst źródłaRau, Jing-Long, i 饒景隆. "Guided Waves in Filament Wound Composite Tubes". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/36277639862425976655.
Pełny tekst źródła國立交通大學
機械工程研究所
86
Filament wound composite pressure vessels are being increasingly used in industry. This has resulted in a critical neeed for reliable and effective nondestructive testing methods for quality assurance and safety assessment. This study presents an analysis of guided wave propagation in laminated composite tubes by using finite element method based on Hamilton's principle. Each lamina of the composite tube is assumed to be transversely isotropic medium with five independent material stiffness components. The phase velocities were determined by numerical computation and compared with measurements. The transient guided waves were excited by a Q-switched Nd;YAG laser and were detected by a broadband conical transducer mounted on the surface of a composite tube. After transformation from local coordinates of eaxh lamina to the global coordinates of the tube, the number of independent material constants is still the same for the ones manufactured with symmetric filament winding at ±a angles .Three of the material constants are directly measured by pulse-echoes of pressure wave and shear wave and shear waves propagating along the thickness of the tube. The remaining two stiffness components are determined by inversion of simplex based on phase velocities of the guided waves.
"Pilot Tube Microtunneling: Profile of an Emerging Industry". Master's thesis, 2011. http://hdl.handle.net/2286/R.I.9519.
Pełny tekst źródłaDissertation/Thesis
M.S. Construction 2011
Chu, Pao-Sheng, i 朱寶聖. "Guided Wave Propagation in a Filament Wound Composite Tube and Determination of Anisotropic Elastic Constants". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/68252099257922711684.
Pełny tekst źródła國立交通大學
機械工程系
89
The first order shear deformation theory for analysis of guided wave propagation in anisotropic circular cylindrical shells is developed in this thesis to determine the elastic stiffness constants of a filament wound composite tube. The phase velocity and group velocity dispersion curves of circumferential waves, torsional waves, longitudinal waves and flexural waves are numerically calculated. The approximate theory with the best fit of shear deformation correction factors has a very good agreement with the exact solution for isotropic tubes within the framework of elasticity and save a large number of computation time. The best determination of the shear deformation correction factor in circumferential direction approaches to Mindlin’s estimation, but the axial one converges to a slightly larger value. The material in each filament of a composite tube is assumed to be transversely isotropic with its symmetry at the winding angle to the axis. As the winding angle increases, phase velocities of the torsional waves become greater and those of the longitudinal waves are decreasingly less. But changes in wave speeds of the flexural waves depend on each individual mode. Six effective stiffness constants, corresponding to five independent elastic constants and winding angle of the composite tube, are determined using simplex algorithm to search the best fit of the least squares of errors among those predicated and measured phase velocities of and modes. The results indicate that the stiffness components , , and achieve proper convergence in a broad range of initial guess values, but and converge under limited conditions.
Gomes, Joana Maria da Silva. "Regeneration of the Peripheral Nerve - Development and Evaluation of Guide Tubes of Biodegradable Polymer". Master's thesis, 2014. https://repositorio-aberto.up.pt/handle/10216/73439.
Pełny tekst źródłaGomes, Joana Maria da Silva. "Regeneration of the Peripheral Nerve - Development and Evaluation of Guide Tubes of Biodegradable Polymer". Dissertação, 2014. https://repositorio-aberto.up.pt/handle/10216/73439.
Pełny tekst źródłaJhang, Jhih-Ming, i 張誌銘. "Measurement and Modeling for the Dispersion Behaviors of Guided Waves Propagating in Two-Layered Tubes". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/31621275794283748423.
Pełny tekst źródła長庚大學
機械工程研究所
93
Zircaloy material often been used in fuel cladding of nuclear power station. When the operation time, it will produce “hydrogen absorbed” in Zircaloy tubes. When reaching the threshold limit value, hydrogen embrittlement will be happened. It will precipitate a layer of ZrH2 on the outer surface of Zircaloy tubes. The hydrogen embrittlement reduces the ductility of Zircaloy tubes. It will influence the structure reliable in nuclear power station. In the past, we detected the hydrogen concentration of Zircaloy tubes by destructive method, for example, hot vacuum extraction method, inert gas fusion method and SEM method. However, these techniques require destructive inspection and cost a lot of money and time, too. Ultrasonic technique can appear the hydrogen concentration of Zircaloy tubes in the dispersion cuves. In the past studies, they ever researched the dispersion relations of uniform distributed hydrogen in Zircaloy tubes. However, It is more complex that precipitating ZrH2 on the outer surface of Zircaloy tubes. It can be seen for two-layered composite material tubes. So, I study the dispersion relations of two-layered tubes in this research, and it is convenient to inspect the hydrogen concentration of Zircaloy tubes. Theory and experiment are separated to research in two stages that is one-layered tubes and two-layered tubes. The theory of one-layered tubes was derived by Gazis. The results are given of a numerical evaluation of a characteristic equation derived by Gazis. The theory of two-layered tubes was derived by Armenakas. The results are given of a numerical evaluation of a characteristic equation derived by him. At the same time, this study also uses non-destructive laser ultrasonic technique to measure the dispersion relations of Zircaloy tubes with precipitating ZrH2. It appears that Theory and experiment conform well, and can use laser ultrasonic technique to measure the dispersion relations of Zircaloy tubes correctly.
Liu, I.-Hung, i 劉一宏. "Inversion Calculation of Material and Geometrical Properties of Two-layered Tubes Based on Dispersion Relation of Guided Waves". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/63916581512804367937.
Pełny tekst źródłaWehinger, Johanna Luise. "A strategy revision to guide Biovilla on the path towards environmental, social, and financial sustainability - recommendations to fine-tune Biovilla´s growth strategy". Master's thesis, 2021. http://hdl.handle.net/10362/132561.
Pełny tekst źródłaHuang, Yi-Yan, i 黃奕彥. "Translation and Interpretation of ""Meditation Chapter"" of ""A Guide to the Bodhisattva's Way of Life"" Explained by Tub bsTan Chos Grags". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/92055922539907482419.
Pełny tekst źródłaCheng-Hong, Yeh, i 葉承鴻. "Inversion Calculation of Material and Geometrical Properties of One-layer Tubes Based on Dispersion Relation of Circumferential Guided Waves". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/74087200754113302469.
Pełny tekst źródła長庚大學
機械工程研究所
95
The characterization of hydrogen concentration (HC) in Zircaloy cladding tubes is an important task. At the same HC, material property (strength and ductility) grown worse quickly with radial hydride than circumferential hydride. So that the important task is not only HC but also RH. Guided waves (GW) propagating in tubes have been extensively used to characterize properties of tubes. In previous study, Axially propagating guided waves (AGW) has been reported to characterize HC in Zircaloys. So, This study is focused on circumferentially propagating guided waves (CGW) to inspect direction of hydride. In this study, a NDE technique employing the LUT and a simplex inversion process is reported for the characterization of radial and circumferential hydride. It’s shown that Young’s modulus of radial hydride be higher than circumferential hydride with CGW, but unchanged with AGW.