Дисертації з теми "Mechanical ablation"
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Fu, Rui. "Thermo-Mechanical Coupling for Ablation." UKnowledge, 2018. https://uknowledge.uky.edu/me_etds/111.
Walsh, Conor James. "Image-guided robots for dot-matrix tumor ablation." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61613.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 203-208).
Advances in medical imaging now provides detailed images of solid tumors inside the body and miniaturized energy delivery systems enable tumor destruction through local heating powered by a thin electrode. However, the use of thermal ablation as a first line of treatment is limited due to the difficulty in accurately matching a desired treatment and a limited region of active heating around an electrode. The purpose of this research is to identify and quantify the current limitations of image-guided interventional procedures and subsequently develop a procedure and devices to enable accurate and efficient execution of image-based interventional plans and thus ablation of a tumor of any shape with minimal damage to surrounding tissue. Current limitations of probe placement for ablation therapy were determined by a detailed retrospective study of 50 representative CT-guided procedures. On average, 21 CT scans were performed for a given procedure (range 11-38), with the majority devoted to needle orientation and insertion (mean number of scans was 54%) and trajectory planning (mean number of scans was 19%). A regression analysis yielded that smaller and deeper lesions were associated with a higher number of CT scans for needle orientation and insertion; highlighting the difficulty in targeting. Another challenge identified was repositioning the instrument distal tip within tissue. The first robot is a patient-mounted device that aligns an instrument along a desired trajectory via two motor-actuated concentric, crossed, and partially nested hoops. A carriage rides in the hoops and grips and inserts an instrument via a two degree-of-freedom friction drive. An imagebased point-and-click user interface relates appropriate clicks on the medical images to robot commands. Mounting directly on the patient provides a sufficiently stable and safe platform for actuation and eliminates the need to compensate for chest motion; thereby reducing the cost and complexity compared to other devices. Phantom experiments in a realistic clinical setting demonstrated a mean targeting accuracy of 3.5 mm with an average of five CT scans. The second robot is for repositioning the distal tip of a medical instrument to adjacent points within tissue. The steering mechanism is based on the concept of substantially straightening a pre-curved Nitinol stylet by retracting it into a concentric outer cannula, and re-deploying it at different axial and rotational cannula positions. The proximal end of the cannula is attached to the distal end of a screw-spline that enables it to be translated and rotated with respect to the casing. Translation of the stylet relative to the cannula is achieved with a second concentric, nested smaller diameter screw that is constrained to rotate with the cannula. The robot mechanism is compatible with the CT images, light enough to be supported on a patient's chest or attached to standard stereotactic frames. Targeting experiments in a gelatin phantom demonstrated a mean targeting error of 1.8 mm between the stylet tip and that predicted with a kinematic model. Ultimately, these types of systems are envisioned being used together as part of a highly dexterous patient-mounted positioning platform that can accurately perform ablation of large and irregularly shaped tumors inside medical imaging machines - offering the potential to replace expensive and traumatic surgeries with minimally invasive out-patient procedures.
by Conor James Walsh.
Ph.D.
Chang, I.-Ta. "Excimer Laser Ablation of Polymer-Clay Nanocomposites." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1333995807.
Payne, Barry. "The role of chromophore on pulsed laser ablation of biological tissue." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43315.
Walter, Aaron Joseph. "Approximate Thermal Modeling of Radiofrequency Cardiac Ablation." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd1002.pdf.
Karim, Nejad Aliabadi Parya. "Development of thermoelectric cooling system for tissue ablation." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7536/.
Lv, Wener. "A novel means of cardiac catheter guidance for ablation therapy of ventricular tachycardia." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87978.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 118-123).
This work presents a system for identifying the site of origin of ventricular tachycardia (VT) and guiding a catheter to that site in order to deliver radio-frequency (RF) ablation therapy. Myocardial infarction (MI), also known as ischemic heart disease, is one of the most common pathophysiologic substrates for the development of ventricular tachycardia (VT). Implantable cardioverter defibrillators (ICDs) have been found to be successful in terminating VT but do not prevent the initiation of the arrhythmia. Alternatively, the radiofrequency (RF) ablation procedure has been recently used as a potentially curative therapy by delivering a high-frequency current at the arrhythmia site in order to disrupt the re-entrant circuit and to prevent the arrhythmia from occurring. However, RF ablation of VT presents a great challenge. The origin of the arrhythmia may be anywhere in the ventricles, and existing techniques used to locate the site require that patients be maintained in VT for 30 to 45 minutes, which leads to blood pressure collapse in 90% of the patients. Recently, we have developed a novel guidance system for the ablative treatment of VT. This system employs an Inverse Solution Guidance Algorithm (ISGA) based upon a single equivalent moving dipole (SEMD) model for the generation of body surface potentials and is able to localize both the arrhythmia site and the ablation catheter in real-time. With the proposed system VT need be induced and maintained for only a few seconds. This system has been shown in our tank experiment and in vivo animal studies to be highly accurate, low cost and reliable. An optimization analysis of the system is also included in this thesis for the purpose of further reducing the cost and surgical risk of the RF ablative therapy.
by Wener Lv.
Ph. D.
Simsek, Bugra. "Ablation Modeling Of Thermal Protection Systems Of Blunt-nosed Bodies At Supersonic Flight Speeds." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615414/index.pdf.
s specific heat capacity is changed by temperature and TGA is a technique in which the mass of a substance is monitored as a function of temperature. Moreover, oxyacetylene ablation tests are conducted for the subliming ablative specimens and measured recession values are compared with the analytically calculated values. Maximum difference between experimental results and analytical results is observed as 3% as seen in Table 7. For the finite element analyses, ANSYS Software is used. A numerical algorithm is developed by using programming language APDL (ANSYS Parametric Design Language) and element kill feature of ANSYS is used for simulation of ablation process. To see the effect of mesh size and time step on the solution of analyses, oxyacetylene test results are used. Numerical algorithm is also applied to the blunt-nosed section of a supersonic rocket which is made from subliming ablative material. Ablation analyses are performed for the nose section because nose recession is very important for a rocket to follow the desired trajectory and nose temperature is very important for the avionics in the inner side of the nose. By using the developed algorithm, under aerodynamic heating, shape change and temperature distribution of the nose section at the end of the flight are obtained. Moreover, effects of ablation on the trajectory of the rocket and on the flow around the rocket are examined by Missile DATCOM and CFD (computational fluid dynamics) analysis tools.
Dilwith, Jason. "Feasibility Study of Laser Ablation using Long Pulsed 300W, CW Single Mode Fiber Laser." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-06132005-191622/.
Ortiz, Luis G. "Design of a chemical sampling and analysis system using excimer laser ablation and quartz microcolumns." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43422.
Buratin, Stefano. "Pulsed laser ablation of silicon : the influence of beam parameters on ablated crater morphology." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8569/.
Tang, Chen. "Novel Performance Evaluation Method for Electrosurgical Ablation by Monopolar Hot Biopsy Forceps." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1461217424.
Devarakonda, Surendra B. "Enhanced Thermal Ablation of Biomaterials Using High-Intensity Focused Ultrasound (HIFU) Energized Nano-particles." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1544001995977567.
Aykan, Serap Fatma. "Numerical Analysis Of Ablation Process On A Two Dimensional External Surface." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606675/index.pdf.
Pearson, Stephen Herbert. "Nonlinear Ball Chain Waveguides For Acoustic Emission And Ultrasound Sensing Of Ablation." ScholarWorks @ UVM, 2014. http://scholarworks.uvm.edu/graddis/256.
Roper, Ryan Todd. "A Study of Radiofrequency Cardiac Ablation Using Analytical and Numerical Techniques." Diss., CLICK HERE for online access, 2003. http://contentdm.lib.byu.edu/ETD/image/etd262.pdf.
Mullenix, Nathan J. "A COUPLED GAS DYNAMICS AND HEAT TRANSFER METHOD FOR SIMULATING THE LASER ABLATION PROCESS OF CARBON NANOTUBE PRODUCTION." University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1131648970.
Journaux-Duclos, Justine. "Ciblage thérapeutique de l'adénocarcinome pancréatique par hyperthermie magnétique ou ablation magnéto-mécanique." Electronic Thesis or Diss., Toulouse 3, 2023. http://www.theses.fr/2023TOU30360.
Due to their physico-chemical properties, magnetic iron oxide nanoparticles (SPION) offer many advantages. They are biocompatible and functionalizable and therefore have already been used as a contrast agent for MRI diagnosis. They can respond to the application of magnetic fields: release thermal energy in response to the application of a high frequency alternating magnetic field (AMF), or generate mechanical forces when they are exposed to low frequency rotating magnetic fields (RMF). Clinical trials using magnetic hyperthermia mediated by SPION and AMF fields have been carried out on glioblastoma and prostate cancer in association with radiotherapy. Nevertheless, the benefit on life expectancy was negligible and adverse effects were noted on adjacent healthy tissues. But our team has previously shown that it is possible to specifically induce tumor cells and microenvironment cells death through the use of low concentrations of targeted magnetic nanoparticle that specifically accumulate in the lysosomes of the targeted cells. Then AMF fields specifically induce the death of target cells by targeted intra-lysosomal magnetic hyperthermia MILH. The mechanisms leading to the death of these cells have been characterized and show that it is initiated in the lysosomes by the generation of ROS according to the Fenton reaction which requires Fe ions and can be catalyzed by an acid pH and an increase of temperature (optimal at 40°C). However, the origin of the Fe ions involved in the Fenton reaction has not been elucidated. Another strategy was also established in the team; it is based on the application of RMF fields which will generate mechanical forces from the SPIONs and induce cell death by targeted intra-lysosomal mechanical ablation. We have chosen as a model, the pancreatic adenocarcinoma particularly resistant to conventional therapies and characterized by the presence of a large and dense microenvironment. In this microenvironment, CAFs (Cancer Associated Fibroblasts) play a key role, in particular through the secretion of extracellular matrix and soluble molecules, limiting the penetration and effectiveness of treatments and contributing to the acquisition of resistance. Cancer cells as well as CAF can overexpress the cholecystokinin receptor type 2 (RCCK2). This membrane receptor has the property of internalizing after binding of its specific agonist: the gastrin. The team has developed functionalized nanoparticles with high heating power vectorized with gastrin peptides (NF@Gastrin). These nanoparticles specifically recognize human pancreatic MiaPaca2 cells and CAFs expressing the CCK2 receptor and accumulate in their lysosomes. The application of AMF (275 kHz, 30 mT) or RMF (1 Hz, 40 mT) fields specifically induces the death of these cells by MILH or targeted intra-lysosomal mechanical ablation. First, we compared the effects of MILH induced by NF@Gastrin to those induced by the same nanoparticles covered with a hermetic silica shell (NF@SiO2@Gastrin), preventing the release of iron under the application of AMF field, in the presence or absence of Ferristatin-II, an inhibitor of iron uptake by the cell. This study demonstrate that the iron involved in the Fenton reaction at the origin of ROS production by MILH came from the endogenous pool of the cell and not from the release of iron by the iron oxide nanoparticles submitted to AMF. Then, we demonstrate that MILH and mechanical ablation increase the expression of damage-associated molecular patterns (DAMPs) on the surface of MiaPaca2 cells and CAFs having specifically internalized NF@Gastrin and stimulate their phagocytosis by macrophages. These two approaches, magnetic hyperthermia and mechanical ablation, could therefore be two new strategies to restore anti-tumor immunity in pancreatic adenocarcinoma. Finally, these two strategies can also modify the pro-tumoral phenotype of CAFs, by inhibiting their migration, decreasing their collagen secretion
Binti, Mohamad Noor Shafini. "Impact of P2RX7 purinoceptor ablation on the morphometric, mechanical and tissue properties in the murine model of Duchenne muscular dystrophy." Thesis, University of Portsmouth, 2016. https://researchportal.port.ac.uk/portal/en/theses/impact-of-p2rx7-purinoceptor-ablation-on-the-morphometric-mechanical-and-tissue-properties-in-the-murine-model-of-duchenne-muscular-dystrophy(60c82bbf-ce54-4054-aa0e-31a39affbd7c).html.
Sockalingam, Subramani. "Coupling of Fluid Thermal Simulation for Nonablating Hypersonic Reentry Vehicles Using Commercial Codes FLUENT and LS-DYNA." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1218801526.
Martin, Nicholas C. "Steady State Simulation of Pyrolysis Gases in an Inductively Coupled Plasma Facility." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/791.
Hanich, Maxwell James. "Analysis of Efficiency of Laser Ablation of Aluminum By Modeling of Plume Shielding Effect." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1595509756016075.
Mullenix, Nathan Joel. "Fully Coupled Model for High-Temperature Ablation and a Reative-Riemann Solver for its Solution." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1271035105.
Wang, Yeqing. "Modeling of lightning-induced thermal ablation damage in anisotropic composite materials and its application to wind turbine blades." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2164.
Boualleg, Abdelmadjid. "Investigations on post-processing of 3D printed thermoplastic polyurethane (TPU) surface." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-41203.
Tillson, Corey. "Investigation of Pyrolysis Gas Chemistry in an Inductively Coupled Plasma Facility." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/692.
Bessière, Francis. "Amélioration des techniques d’ablation pour le traitement des arythmies cardiaques : nouvelles modalités diagnostiques et thérapeutiques par ultrasons." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1225/document.
At the crossroads of medicine and physics, this work aimed to provide innovative diagnostic and therapeutic tools based on ultrasound, in the field of cardiac electrophysiology. A system capable of delivering HIFU into the heart by a transesophageal route using ultrasound (US) imaging guidance was developed and tested in vivo in six male pigs. HIFU exposures were performed on atria and ventricles. At the time of autopsy, visual inspection identified thermal lesions in the targeted areas in three of the animals. These lesions were confirmed by histologic analysis (mean size: 5.5 mm2 x 11mm2). No esophageal thermal injury was observed. One animal presented with bradycardia due to an atrio-ventricular block, which provides real-time confirmation of an interaction between HIFU and the electrical circuits of the heart. There was still a lack of accuracy, mainly related to cardiac motion, and to anatomical structures in between the targets and the transducer. It was mainly related to the in vivo model and its anatomy, far from the human’s. The search for a better model led to conclusive imaging tests on baboons. Additional experiments were conduced in order to improve the mapping of ventricular arrhythmias and the monitoring of lesion formation during ablation. First, experiments were conducted on left ventricles of four isolated working mode swine hearts. The protocol aimed at demonstrating that different patterns of mechanical activation could be observed whether the ventricle was in sinus rhythm, paced from the epicardium, or from the endocardium. Electromechanical wave imaging (EWI) acquisitions were recorded on the anterior, lateral, and posterior segments of the left ventricle. Loop records were blindly assigned to two readers. EWI sequences interpretations were correct in 89% of cases. The overall agreement rate between the two readers was 83%. When in a paced ventricle, the origin of the wave front was focal and originating from the endocardium or the epicardium. In sinus rhythm, wave front was global and activated within the entire endocardium towards the epicardium at a speed of 1.7±0.28 m.s-1. Wave front speeds were respectively measured when the endocardium or the epicardium were paced at a speed of 1.1 ± 0.35 m.s-1 vs 1.3±0.34 m.s-1 (p=NS). Lastly, we investigated the feasibility of a dual therapy and imaging approach with the same transoesophageal device. We demonstrated on ex-vivo samples that transoesophageal shear wave imaging (SWE) can map the extent of the HIFU lesions. HIFU ablation was performed with the transoesophageal probe on ex-vivo chicken breast samples (n=3), then atrium (left, n=2) and ventricle (left n=1, right n=1) of swine heart tissues. SWE provided stiffness maps of the tissues before and after ablation. Areas of the lesions were obtained by tissue color change with gross pathology and compared to SWE. Shear modulus of the ablated zones increased from 4.8±1.1 kPa to 20.5+/-10.0 kPa (ratio 5.0±3.2) in the chicken breast, from 12.2±4.3 kPa to 30.3±10.3 (ratio 3.2±2.0) in the atria and from 21.2±3.3kPa to 73.8±13.9kPa (ratio 3.7±1.2) in the ventricles. On gross pathology, the size of the lesions ranged from 0.1 to 1.5cm2 in the imaging plane area and morphometric characteristics were fitting with elasticity-estimated depths and widths of the lesions
Choi, Hae Woon. "Femtosecond laser material processing for micro-/nano-scale fabrication and biomedical applications." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1184883900.
Vesperini, Doriane. "Biomechanical study of cells in microfluidic flow : application to sorting and platelet production." Thesis, Compiègne, 2018. http://www.theses.fr/2018COMP2437/document.
When they mature in the bone marrow, the precursors of platelets, called megakaryocytes, grow and extend protrusions able to join blood circulation. There these protrusions elongate and break into platelets. Microfluidic techniques for in vitro platelet production represent a promising alternative to donation. In order to enhance platelet production and match the needs of clinical applications such as transfusion, we need to better understand the fragmentation of megakaryocytes into platelets. Our contribution will be described in this manuscript in two main axes. First, in order to know if mechanical properties of megakaryocytes can indicate their maturity stage, we develop a cell sorting method based on deformability. The method is first validated with microcapsules. Their mechanical properties are determined by inverse analysis from their shape under flow in straight microchannels. Then the device is downscaled. The characterization of cell mechanical properties are performed using inverse analysis and tipless atomic force microscopy. Second, we study megakaryocyte elongation and rupture in a microfluidic device. We quantify the spatial and temporal variations of the elongation rate and develop a laser ablation protocol to trigger and study the rupture of elongating cells
Vidal, José Tort. "Desenvolvimento de um sistema opto-mecânico para micro usinagem com laser de femtosegundos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-10082011-150643/.
Machining of very small structures has been made with nano, pico and femtosecond pulsed lasers. Among then, only femtosecond lasers may result in nonthermal interaction with matter, avoiding melting, formation of slag and heat affected zone. Mass production with such lasers yet can only be considered in cases where nonthermal effects are of prime importance. This is the case in machining of semiconductors and electric steels, the production of MEMS, microchannels, and many medical and biological devices. Hence, a workstation for production of such kind of microstructures was built with the capability of controlling the main parameters necessary for the machining process. Control of the laser fluence and focus positioning are the main concern in this kind of processing. So, the control of the laser beam diameter (in the focus) and of the pulse energy must be very precise. Positioning of focal point with micrometric precision in the three axes is also fundamental. The system built in this work provides solutions for these problems incorporating several sensors and positioning stages simultaneously controlled by a single software. The workstation receives a laser beam coming from another laboratory and delivers it to the surface of the sample managing with precision the main process parameters. The system can dynamically control the energy, number of pulses and positioning for each individual laser spot. Besides, the spatial distribution of the laser intensity, polarization and vibrations were also measured and optimized. The system was tested and calibrated with threshold ablation measurement for silicon, which is well studied in this regime of laser operation. The results where compared with data found in the literature and attested the reliability and precision of the system. Besides the increase in precision, the automation also turned much faster the data acquisition. Threshold ablation for metallic molybdenum was also obtained and resulted in data not found in the literature yet. Concluding the initial goal, the workstation was developed and is ready to be used in studies that can lead to production of micrometric structures.
Bessière, Francis. "Amélioration des techniques d’ablation pour le traitement des arythmies cardiaques : nouvelles modalités diagnostiques et thérapeutiques par ultrasons." Electronic Thesis or Diss., Lyon, 2019. http://www.theses.fr/2019LYSE1225.
At the crossroads of medicine and physics, this work aimed to provide innovative diagnostic and therapeutic tools based on ultrasound, in the field of cardiac electrophysiology. A system capable of delivering HIFU into the heart by a transesophageal route using ultrasound (US) imaging guidance was developed and tested in vivo in six male pigs. HIFU exposures were performed on atria and ventricles. At the time of autopsy, visual inspection identified thermal lesions in the targeted areas in three of the animals. These lesions were confirmed by histologic analysis (mean size: 5.5 mm2 x 11mm2). No esophageal thermal injury was observed. One animal presented with bradycardia due to an atrio-ventricular block, which provides real-time confirmation of an interaction between HIFU and the electrical circuits of the heart. There was still a lack of accuracy, mainly related to cardiac motion, and to anatomical structures in between the targets and the transducer. It was mainly related to the in vivo model and its anatomy, far from the human’s. The search for a better model led to conclusive imaging tests on baboons. Additional experiments were conduced in order to improve the mapping of ventricular arrhythmias and the monitoring of lesion formation during ablation. First, experiments were conducted on left ventricles of four isolated working mode swine hearts. The protocol aimed at demonstrating that different patterns of mechanical activation could be observed whether the ventricle was in sinus rhythm, paced from the epicardium, or from the endocardium. Electromechanical wave imaging (EWI) acquisitions were recorded on the anterior, lateral, and posterior segments of the left ventricle. Loop records were blindly assigned to two readers. EWI sequences interpretations were correct in 89% of cases. The overall agreement rate between the two readers was 83%. When in a paced ventricle, the origin of the wave front was focal and originating from the endocardium or the epicardium. In sinus rhythm, wave front was global and activated within the entire endocardium towards the epicardium at a speed of 1.7±0.28 m.s-1. Wave front speeds were respectively measured when the endocardium or the epicardium were paced at a speed of 1.1 ± 0.35 m.s-1 vs 1.3±0.34 m.s-1 (p=NS). Lastly, we investigated the feasibility of a dual therapy and imaging approach with the same transoesophageal device. We demonstrated on ex-vivo samples that transoesophageal shear wave imaging (SWE) can map the extent of the HIFU lesions. HIFU ablation was performed with the transoesophageal probe on ex-vivo chicken breast samples (n=3), then atrium (left, n=2) and ventricle (left n=1, right n=1) of swine heart tissues. SWE provided stiffness maps of the tissues before and after ablation. Areas of the lesions were obtained by tissue color change with gross pathology and compared to SWE. Shear modulus of the ablated zones increased from 4.8±1.1 kPa to 20.5+/-10.0 kPa (ratio 5.0±3.2) in the chicken breast, from 12.2±4.3 kPa to 30.3±10.3 (ratio 3.2±2.0) in the atria and from 21.2±3.3kPa to 73.8±13.9kPa (ratio 3.7±1.2) in the ventricles. On gross pathology, the size of the lesions ranged from 0.1 to 1.5cm2 in the imaging plane area and morphometric characteristics were fitting with elasticity-estimated depths and widths of the lesions
Crocker, Ryan Campbell. "Direct Numerical Simulation Of Ablative Boundaries In Turbulent And Laminar Flows." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/397.
VIDAL, JOSE T. "Desenvolvimento de um sistema opto-mecanico para micro usinagem com laser de fentossegundos." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9563.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Benchikh, Épouse Sbaï Nadia. "Couches minces nanostructurées de carbone amorphe dopées ou alliées : Elaboration par ablation laser femtoseconde et Caractérisations." Phd thesis, Université Jean Monnet - Saint-Etienne, 2005. http://tel.archives-ouvertes.fr/tel-00142211.
L'ablation laser en régime femtoseconde est la technique utilisée pour la synthèse des couches minces de DLC dopées ou alliées. Ce sujet met également en évidence l'apport de cette technique sur les propriétés morpho-structurales et physiques des DLC dopés ou alliés.
O'Brien, Daniel. "Ablation Laser de microparticules de Terfenol-D (Tb0.3Dy0.7Fe1.92) en aérosol etdépôt supersonique des nanoparticules en résultant pour la fabrication defilms magnétostrictifs épais." Phd thesis, Ecole Centrale de Lille, 2007. http://tel.archives-ouvertes.fr/tel-00137712.
Les couches déposées ont été caractérisées par la méthode des poutres pour déterminer le module élastique et le niveau de magnétostriction. Les couches étant poreuses en raison de leur nature granulée, leur module élastique était réduit à environ 15 GPa. Le niveau de magnétostriction des couches était d'environ 15 ppm ; cette magnétostriction réduite (1/30 de celui des couches fines) étant dû à un problème d'oxydation. Une analyse spectroscopique du plasma produit par l'ablation a permit la détermination de la source d'oxydation. L'étendue de l'oxydation des couches est apparue directement dépendante de la taille des microparticules utilisées initialement pour fabriquer les nanoparticules. Après calculs théoriques, pour des densités typiques d'aérosol utilisées dans le procédé LAM, il a été démontré que les nanoparticules fabriquées à partir de microparticules de plus de 3 µm de diamètre n'étaient pas affectées de façon significative par les impuretés présentes dans le gaz ou par l'oxydation de surface des microparticules. En revanche, les nanoparticules fabriquées à partir de microparticules de 0,3 µm de diamètre ou moins étaient, elles, oxydées et les couches en résultant l'étaient aussi. Experimentalement le diamètre des microparticules injectées en aérosol était présumé être entre ces deux cas.
Schroeder, Olivia. "Verification and Validation Studies for the KATS Aerothermodynamics and Material Response Solver." UKnowledge, 2018. https://uknowledge.uky.edu/me_etds/122.
Helvey, Jacob. "Experimental Investigation of Wall Shear Stress Modifications due to Turbulent Flow over an Ablative Thermal Protection System Analog Surface." UKnowledge, 2015. http://uknowledge.uky.edu/me_etds/57.
Clark, Ian Gauld. "Aerodynamic design, analysis, and validation of a supersonic inflatable decelerator." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/34708.
Avrit, Antoine. "Étude du comportement d’ablation d’une structure solide par un jet liquide chaud." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0281.
Safety studies for fast neutron reactors with sodium led to the development of mitigation systems for severe accidents. During a hypothetical severe accident, at least part of the reactor's core melts, leading to the formation of corium. The corium has to be relocated to prevent any criticality problems. Therefore, transfer tubes were integrated to the design of the core to relocate the corium from the core to a core-catcher. A jet of corium exits the transfer tubes and spreads on the core-catcher, allowing a better cooling of the corium. However, thermal ablation of the core-catcher will occur as the temperature of the corium is very high (~ 2000 - 3000 K). Thus, the core-catcher has to be dimensioned to prevent any breach due to the ablation. Experiments were performed during a previous thesis to improve understanding of the phenomenon of ablation by a free-surface jet, with a bench called HAnSoLO (Hot AblatioN of a SOlid by a Liquid - Observations). New results were obtained in the present work to address additional phenomenologies. For instance, the ablation of a solid by an immersed jet was studied. This is another situation that could occur in the real case. The effect of the roughness of the impacted solid was also addressed, and it was shown that taking roughness into account is important to design the core-catcher. All these results were used to validate a CFD code. In particular, the ablation result obtained through the numerical simulations were very similar to the experimental results for the immersed jet case. The simulations and experiments will be completed in the future to numerically treat the ablation of a metallic solid by a corium jet under reactor conditions
Davuluri, Raghava Sai Chaitanya. "Modeling of spallation phenomenon in an arc-jet environment." UKnowledge, 2015. https://uknowledge.uky.edu/me_etds/63.
Löffler, Markus. "Nanomanipulation and In-situ Transport Measurements on Carbon Nanotubes." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-33242.
Mit dem Aufkommen von Mikroelektronik und mikromechanischen Systemen wurden die Vorteile miniaturisierter Geräte augenscheinlich. Mit der Entdeckung von Kohlenstoff-Nanoröhren durch Iijima 1991 wurde ein Material gefunden, welches überlegene Eigenschaften wie hohe Festigkeit, exzellente elektrische und Wärmeleitfähigkeit zeigt, während es zeitgleich leicht und flexibel ist. Diese Eigentschaften können durch eine Änderung der spezifischen atomaren Anordnung in der Nanoröhrenhülle beeinflusst werden. Der erste Teil dieser Dissertationsschrift behandelt einen neuartigen Syntheseansatz, welche die bekannten Syntheserouten der chemischen Gasphasenabscheidung und Laserablation kombiniert. Die Ergebnisse bezüglich des Durchmessers und der Ausbeute lassen sich gut mit einem etablierten Modell der Nukleation und des Wachstums von Kohlenstoff-Nanoröhren beschreiben - sie erweitern es, indem sie einen größeren Parameterraum berücksichtigen. Des Weiteren wurde konventionelle Laserablation benutzt, um C-13 angereicherte Kohlenstoff-Nanoröhren herzustellen, deren Durchmesser nicht nur von den üblichen Parametern, sondern auch vom C-13 Anteil abhängt. Diese Abhängigkeit geht mit der veränderten thermischen Leitfähigkeit von Isotopenmischungen einher. Die Manipulation von Kohlenstoff-Nanoröhren in einem Transmission-Elektronenmikroskop formt den zweiten Teil der Dissertationschrift. Mit Hilfe eines in-situ Manipulators wurden vielfältige Experimente durchgeführt, um die mechanischen und elektrischen Eigenschaften der Kohlenstoff-Nanoröhren zu bestimmen. Zweipunktmessungen des Widerstands einzelner Nanoröhren und die Beobachtung des Versagens einzelner Kohlenstoffschichten erlaubte die Bestimmung der Stromtragfähigkeit einzelner Hüllen. Mit Hilfe eines elektrischen Stromes konnte eine Nanoröhre durch die veränderung der Struktur in ihren elektrischen Eigenschaften verändert werden. Unter Verwendung dauerhaften oder gepulsten Gleichstroms konnte die Eisen- oder Zementit-Füllung der Kohlenstoff-Nanoröhren in eine polaritätsabhängige Richtung bewegt werden. Die Füllung wurde dabei durch die Wände der Nanoröhre geführt. Abhängig von Strom, Form der Nanoröhre und Zusammensetzung der Füllung ließen sich verschiedene Bereiche des Materialtransports identifizieren, u.a. das Umarbeiten einiger innerer Kohlenstoffschichten. Ein hoher Strom hingegen bewirkt eine Umarbeitung der kompletten Nanoröhre und strominduziertes Wachstum von Kohlenstoff-Nanostrukturen mit veränderter Morphologie. Mit Hilfe der gewonnenen Resultate wurde ein Transportmodell entwickelt, welches den Impulstransfer von Elektronen an Füllungsatome sowie einen festen Füllungskern während des Transports diskutiert. Messungen der mechanischen Eigenschaften, welche mit Hilfe von resonanter oder nicht-resonanter elektrischer Anregung von Schwingungen im Transmissions-Elektronenmikroskop durchgeführt wurden bilden den Abschluss der Arbeit. Durch die Beobachtungen konnten mit einem modifizierten Euler-Bernoulli-Balkenmodell wichtige mechanische Eigenschaften bestimmt werden
Arnal, Bastien. "Elastographie pour le suivi des thérapies par ultrasons focalisés et nouveau concept de cavité à retournement temporel pour l'histotripsie." Phd thesis, Université Paris-Diderot - Paris VII, 2013. http://pastel.archives-ouvertes.fr/pastel-00786523.
Zhang, Lijun. "Thermal and mechanical phenomena in laser-material interaction." 2008. http://proquest.umi.com/pqdweb?did=1622196481&sid=6&Fmt=2&clientId=14215&RQT=309&VName=PQD.
Title from title screen (site viewed Mar. 5, 2009). PDF text: 97 p. : ill. (some col.) ; 3.12 Mb. UMI publication number: AAT 3331445. Includes bibliographical references. Also available in microfilm and microfiche formats.
Kurzawski, Andrew Joseph. "Ablation and ignition by impinging jet flows." Thesis, 2013. http://hdl.handle.net/2152/23684.
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Barr, Benjamin Witten. "Investigation and modeling of coupled thermochemical and thermomechanical erosion in thermally degrading systems." Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-05-5554.
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Wang, Xiaoliang. "Ultra-short pulsed laser surface processing and decontamination." 2008. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.000050472.
(10726149), Weirong Yuan. "PHASE CHANGE AND ABLATION STUDY OF METALS BY FEMTOSECOND LASER IRRADIATION USING HYBRID TTM/MD SIMULATIONS." Thesis, 2021.
Cloutier, Martin. "Healing of Calvarial Wounds Created by Er:YAG Laser Irradiation in Comparison with Conventional Mechanical and Femtosecond Laser Ablation in Presence or Absence of BMPs." Thesis, 2009. http://hdl.handle.net/1807/18264.
(10725372), Rajan Nitish Jain. "Intrinsic Self-Sensing of Pulsed Laser Ablation in Carbon Nanofiber-Modified Glass Fiber/Epoxy Laminates." Thesis, 2021.
Scharf, Thorsten. "Depositionsmechanismen, Struktur und mechanische Eigenschaften laserdeponierter Poly(methyl methacrylat)-Filme." Doctoral thesis, 2007. http://hdl.handle.net/11858/00-1735-0000-0006-B44E-9.