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Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: Freehand; inertial tracking; Ultrasound. Includes bibliographical references (leaves 221-223).

Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on Nov. 10, 2009. "June 2009." "In partial fulfillment of the requirements for the degree [of] Master of Science in Mechanical Engineering." "Presented to the faculty of California Polytechnic State University, San Luis Obispo." Major professor: John Ridgely, Ph.D. Includes bibliographical references (p. 91-97).

Στόχος της παρούσας διπλωματικής εργασίας, η οποία εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών, είναι η μελέτη και κατασκευή διάταξης για την παλμοδότηση και τον έλεγχο ενός κινητήρα τύπου ultrasonic, χρησιμοποιώντας ψηφιακό μικροελεγκτή ή FPGA. Αρχικά γίνεται μια παρουσίαση των χαρακτηριστικών των πιεζοηλεκτρικών κινητήρων, γίνεται αναφορά στην αρχή λειτουργίας τους και στα ισοδύναμα κυκλώματα που χρησιμοποιούνται για την ανάλυση της λειτουργίας τους. Στη συνέχεια παρουσιάζονται οι ηλεκτρονικοί μετατροπείς ισχύος που χρησιμοποιούνται για τον έλεγχο των κινητήρων αυτού του τύπου και γίνεται θεωρητική ανάλυση του τρόπου λειτουργίας τους και των μεθόδων παλμοδότησής τους και προσομοιώνεται ένας μονοφασικός αντιστροφέας παλμοδοτούμενος με τη μέθοδο ημιτονοειδούς διαμόρφωσης εύρους παλμών. Ακολουθεί μία περιγραφή των χαρακτηριστικών του μικροελεγκτή που χρησιμοποιήθηκε και του κώδικα του προγράμματός του. Στο επόμενο βήμα πραγματοποιείται η μελέτη και η κατασκευή ενός μετατροπέα συντονισμού για τον έλεγχο του κινητήρα, λόγω περιορισμών που τέθηκαν από το κύκλωμα παλμοδότησης και τέλος παρατίθενται παλμογραφήματα και μετρήσεις που προέκυψαν από τα πειράματα που διενεργήθηκαν. / The goal of this diploma thesis is the study and the construction of a converter in order to drive and control an ultrasonic motor, using digital microcontroller or FPGA.

Cooling channels are designed in blades to protect the blades from damage at high temperature in a gas turbine. ELE Advanced Technology Ltd. is a UK company specialised in machining cooling channels in turbine blades using electro-chemical techniques. The wall thicknesses between these cooling channels and the surface of the turbine blade influences the performance of cooling channels and are required to be accurately machined and then inspected. At present, the company measures the wall thicknesses using a hand-held contact ultrasonic probe, which is time-consuming and not very accurate. In this project, an inspection machine has been designed and built for the purpose of automating the procedure of measuring wall thicknesses in turbine blades. The inspection machine measures wall thicknesses based on immersion ultrasonic testing technique and the actuator is a six-axis industrial robot controlled by a computer. Control algorithms have been developed to automate the entire measuring process. Acquired ultrasonic data is also automatically processed using Matlab scripts for wall thickness evaluation. However, prior to the ultrasonic measurement, the probe path has to be calculated. Matlab script has been developed to automatically calculate a probe path using a point cloud of the blade digitized on a CMM as an input. The calculation of the probe path, in general, involves triangulation, parameterisation and B-spline surface approximation. Normal 3D triangulation methods were tested; nevertheless, the results were unsatisfactory. Therefore, a triangulation algorithm is developed based on B-spline curve and 2D Delaunay triangulation. After the probe path is calculated, a localisation method, based on iterative closest point algorithm, is implemented to transform the probe path from CMM to the inspection machine. Several experiments were designed and conducted to study the capability of the ultrasonic probe. Experimental results confirmed the feasibility of using an immersion ultrasonic probe for measuring the wall thicknesses; however, the experiments revealed several limitations of immersion ultrasonic testing, such as the angle of incidence of ultrasonic waves must be maintained within an angular deviation of ±1° from the surface normal to achieve accurate test results. Wall thicknesses of three turbine blades from one batch were measured on the inspection machine. A CT scan image was used as reference to compare the measured wall thicknesses with results obtained using contact probes. The comparison showed the wall thicknesses measured on the inspection machine were much more accurate than using contact probes.

AIM & HYPOTHESIS: We hypothesized that the piezoelectric knife increases bone remodeling. The effect of a piezotome 2 prototype with different puissance and modulation settings on bone biology was compared under different bone resorption and/or bone formation conditions using an ex-vivo live bone organ culture MATERIALS & METHODS: We utilized an ex-vivo mouse calvarial bone culture system a n d piezocision surgical techniques with variable puissance and modulation settings under conditions of static versus dynamic, and formation versus resorption in order to decipher cellular, molecular, biological and genetic perturbations induced by piezocision surgery. In addition, we tested its impact on calvarial bone organ cultures in the presence of drugs such as bisphosphonate (zolendronic acid, ZOL) and insulin or its impact on bone healing with bone graft material such as Enamel matrix derivative (Emdogain). RESULTS: The impact of the piezoelectric knife extends beyond the immediate site of mineralized bone defect/damage. The impact is ~6 times greater than the apparent initial mineralized bone injury, 1.6 mm2, and extends to immediate surrounding local periosteal and endosteal cell layers, 11 mm2, leaving the mineralized bone layer intact. There were also major differences between the static and dynamic model systems in bone defect viii healing, resorption and new bone formation. There are also differences between the piezoelectric knife and bur in bone resorption and formation models and in both treated before or at the same time of the injury with bisphosphonate. In the calvarial defect repair model the defect closed much faster with the piezoelectric knife than with the bur. In a comparative study with controls versus piezotome or bur, and piezotome versus bur complete genomic analysis of changes revealed a large number of major differences in genomic expression levels. CONCLUSION: The extended effect of piezocision on the surrounding bone lining cells of the bone defect including de-vitalization of the proximal osteocytes within the intact mineralized bone matrix thet primes the bone to undergo rapid turnover. Piezocision incorporates high-frequency vibrational energy that can be transmitted a significant distance within the mineral phase and exploits the inherent bone cellular response mechanism(s) as defined by the global genearray analysis. / 2020-06-13T00:00:00Z

Orientador: José Luiz Laus / Banca: Fabricio Vilella Mamede / Banca: Paola Castro Moraes / Resumo: A pesquisa foi desenvolvida visando-se a se avaliarem alterações nas dimensões de estruturas do bulbo de olho de cães da raça cocker spaniel inglês, machos e fêmeas, com e sem catarata, à ultrasonografia transcorneal nos modos A e B. Dezesseis pacientes (n = 16, 32 olhos, 10 machos, 6 fêmeas) com catarata e idade superior a 8 anos e um grupo controle sem catarata (n =7, 14 olhos, 2 manchos, 5 fêmeas) foram avaliados. Realizou-se ultrasonografia transcorneal nos modos A e B com transdutor de 10 MHz. Os dados referentes à ecobiometria, foram avaliados estatisticamente ao teste ANOVA de via única e os resultados expressos em média e desvio padrão (±DP). A incidência de catarata entre gênero foi avaliada estatisticamente ao teste de Fisher's. O comprimento axial do bulbo do olho dos pacientes com catarata e dos do grupo controle respectivamente, foi de 19.909 ± 1,103 mm; 19,958 ± 1,050mm. Para a câmara anterior, encontraram-se 3,041 ± 0,828 mm; 3,373 ± 1,040mm, respectivamente. Para o diâmetro lenticular foram de 6,817 ± 1,117 mm; 7,062 ± 0,477mm, respectivamente, e para o segmento posterior foram 10,056 ± 0,754mm; 9,523 ± 0,705mm. Não se encontraram diferenças significativas entre olhos com catarata e os controles, tampouco entre machos e fêmeas com e sem catarata. Tampouco foi encontrada diferença em quanto à incidência das cataratas entre ambos os sexos (P > 0.05). / Abstract: The present study was conceived to evaluate A- and B-mode ultrasonographic changes in the thickness of various structures of the eyeball in male and female English Cocker Spaniel dogs with and without cataracts. Sixteen dogs with cataracts (36 eyes, 10 males, 6 females), and seven normal dogs (14 eyes, 2 males, 5 females) older than eight years were selected. A- and B-mode ultrasonography was performed with a 10 MHz transducer. Echobiometry values were evaluated statistically by one way ANOVA. Incidence of cataract among gender was assessed by Fisher's excat test. Mean and standard deviations of various ocular structures for dogs with and without cataracts were, respectively, anterior chamber: 3.041 ± 0.828 mm, 3.373 ± 1.040 mm; lens: 6.817 ± 1.117 mm, 7.062 ± 0.477 mm; vitreous: 10.056 ± 0.754 mm, 9.523 ± 0.705 mm; and axial length: 19.909 ± 1.103 mm; 19.958 ± 1.050 mm. Ocular measurements between right and left eyes, males and females, as well as in eyes with and without cataract were not significantly different. Incidence between gender were not significantly (P > 0.05). / Mestre

This thesis is focused on non-contact air-coupled ultrasonic Non-Destructive Evaluation (NDE) of Carbon-Carbon (C/C) disc brake materials. The minimum detectable defect size in the C/C composite disc brakes up to the maximum thickness of 1 7/16" (36.33 mm) using 120, 225 and 400 kHz transducers was investigated in the experimental section of this thesis. The effect of scanning increment step size on resolution of the final C-scan image was also investigated. The results indicated that the 12.7 mm diameter flat bottom drilled holes were reliably detectable using 225 kHz transducers. The flat bottom drilled holes and the side drilled holes of 6.35 mm in diameter were detectable on the final C-scan images of 225 kHz testing mainly due to the known locations of the defects. Results showed that testing frequency of 120 kHz provides very transparent C-scans. Testing frequency of 225 kHz provides also good transparency and better resolution. Testing frequency of 400 kHz did not provide satisfactory results. No advanced signal filtering techniques were utilized during the experiments. The relationship between the speed of sound in C/C material and the carbon fiber orientation in the carbon matrix needs to be investigated. The air-coupled ultrasonic testing of the C/C composite disc brake samples was conducted at the Center for Non-Destructive Evaluation at Iowa State University.

Made available in DSpace on 2016-08-29T15:32:56Z (GMT). No. of bitstreams: 1 tese_5744_Dissertation_MartinsRS20131108-144619.pdf: 9401224 bytes, checksum: 3db21435dc365ec6e0dd83f6c3b5e644 (MD5) Previous issue date: 2012-05-23 / A indústria de petróleo e gás requer medições de vazão com baixa incerteza, uma vez que são estabelecidas por lei. Contudo, curvas e outros obstáculos são comumente encontrados nesse cenário, o que pode afetar a qualidade da medição de vazão em função de perturbações no escoamento, tais como swirl e assimetrias no peril de velocidades. Medidores de vazão por ultrassom de um canal são frequentemente utilizados em instalações de gás de queimadores, apesar de serem sensíveis a tais perturbações. O presente trabalho usa códigos comerciais de CFD para obter o escoamento à jusante de instalações com uma curva e duas curvas, visando a investigar a magnitude e o comportamento de tais efeitos na medição de vazão. Integração numérica é utilizada para diversos arranjos de caminho acústico, simulando medidores de vazão por ultrassom de um canal em várias condições para avaliar o desvio do fator de correção em escoamentos perturbados. Números de Reynolds de 1 x 104 a 2 x 106 são considerados. Ângulos de montagem dos transdutores de 0° a 180° são testados e posições axiais até 80D à jusante do obstáculo são avaliadas. Os resultados indicam que medidores de vazão por ultrassom são sensíveis aos efeitos de acidente de linha. O desvio do fator de correção mostra-se, em geral, consideravelmente maior que 2% em distâncias menores que 20D, conforme recomendado por alguns fabricantes e por leis. Não obstante, tais desvios podem atingir 0,01% em algumas configurações específicas, o que sugere que a medição de vazão por ultrassom pode ser melhorada pelo rearranjo do aparato em posição angular favorável e, principalmente, pela implementação de funções específicas para fatores de correção em condições perturbadas.