Thesis (M.S.)--University of Michigan, 1984.

Thesis (Ph. D.)--University of Southern California, 1999. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Southern California, 1999. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Charles Link, Dept. of Economics. Includes bibliographical references.

Thesis (Ph.D.)--Baylor University, 2009. / Includes bibliographical references (p. 77-79).

In 1998, the Philippines introduced book-building pricing mechanisms for Initial Public Offerings. Almost all capital raised through IPOs in the Philippines is done using a book-building pricing method, however a significant number of IPOs still occur using non-book-building methods. Understanding why book-building has become the dominant pricing mechanism but yet non-book-building methods still survive is the aim of this paper. I find that unlike other countries where the introduction of book-building leads to higher total issue costs for individual issuers and unlike theory which suggests the increased effort of book-building should come with increased costs, IPOs that use book-built pricing in the Philippines actually have a lower total issue cost as a percentage of the total issue size compared to issuers who use non-book-building methods. This being the case, explaining why non-book-built IPOs still occur is even more interesting. I find that the large variance in size and the low volume of IPOs in the Philippines creates a bifurcated market where it is uneconomical for underwriters to use book-building to service small firms who want to IPO. The harder phenomenon to explain is the choice by firms who are large enough to book-build to use non-book-built methods. I suggest that the developing sophistication of the local market as well as the relationship driven aspect of business in the Philippines are two possible explanations.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This dissertation presents the design and practical demonstration of a flight control system (FCS) that is capable of autonomously landing a fixed-wing, unmanned aerial vehicle (UAV) on a stationary platform aided by a high-precision differential global positioning system. This project forms part of on-going research with the end goal of landing a fixed-wing UAV on a moving platform (for example a ship’s deck) in windy conditions. The main aim of this project is to be able to land the UAV autonomously, safely and accurately on the runway. To this end, an airframe was selected and equipped with an avionics payload. The equipped airframe’s stability derivatives were analysed via AVL and the moment of inertia was determined by the double pendulum method. The aircraft model was developed in such a way that the specific force and moment model (high bandwidth) is split from the point-mass dynamics of the aircraft (low bandwidth) [1]. The advantage of modelling the aircraft according to this unique method, results in a design that has simple decoupled linear controllers. The inner-loop controllers control the high-bandwidth specific accelerations and roll-rate, while the outer-loop controllers control the low-bandwidth point-mass dynamics. The performance of the developed auto-landing flight control system was tested in software-in-the-loop (SIL) and hardware-in-the-loop (HIL) simulations. A Monte Carlo non-linear landing simulation analysis showed that the FCS is expected to land the aircraft 95% of the time within a circle with a diameter of 1.5m. Practical flight tests verified the theoretical results of the developed controllers and the project was concluded with five autonomous landings. The aircraft landed within a circle with a 7.5m radius with the aiming point at the centre of the circle. In the practical landings the longitudinal landing error dominated the landing performance of the autonomous landing system. The large longitudinal error resulted from a climb rate bias on the estimated climb rate and a shallow landing glide slope. / AFRIKAANSE OPSOMMING: Hierdie skripsie stel die ontwikkeling en praktiese demonstrasie van ʼn self-landdende onbemande vastevlerkvliegtuigstelsel voor, wat op ʼn stilstaande platform te lande kan kom met behulp van ʼn uiters akkurate globale posisionering stelsel. Die projek maak deel uit van ʼn groter projek, waarvan die doel is om ʼn onbemande vastevlerkvliegtuig op ʼn bewegende platform te laat land (bv. op ʼn boot se dek) in onstuimige windtoestande. Die hoofdoel van die projek was om die vliegtuig so akkuraat as moontlik op die aanloopbaan te laat land. ʼn Vliegtuigraamwerk is vir dié doel gekies wat met gepaste avionica uitgerus is. Die uitgeruste vliegtuig se aerodinamsie eienskappe was geanaliseer met AVL en die traagheidsmoment is deur die dubbelependulum metode bepaal. Die vliegtuigmodel is op so ‘n manier onwikkel om [1] die spesifieke krag en momentmodel (vinnige reaksie) te skei van die puntmassadinamiek (stadige reaksie). Die voordeel van hierdie wyse van modulering is dat eenvoudige ontkoppelde beheerders ontwerp kon word. Die binnelusbeheerders beheer die vinnige reaksie-spesifieke versnellings en die rol tempo van die vliegtuig. Die buitelusbeheerders beheer die stadige reaksie puntmassa dinamiek. Die vliegbeheerstelsel is in sagteware-in-die-lus en hardeware-in-die-lus simulasies getoets. Die vliegtuig se landingseienskappe is ondersoek deur die uitvoer van Monte Carlo simulasies, die simulasie resultate wys dat die vliegtuig 95% van die tyd binne in ʼn sirkel met ʼn diameter van 1.5m geland het. Praktiese vlugtoetse het bevestig dat die teoretiese uitslae en die prakties uitslae ooreenstem. Die vliegtuig het twee suksesvolle outomatiese landings uitgevoer, waar dit binne ʼn 7.5m-radius sirkel geland het, waarvan die gewenste landingspunt die middelpunt was. In die outomatiese landings is die longitudinale landingsfout die grootse. Die groot longitudinale landingsfout is as gevolg van ʼn afset op die afgeskatte afwaartse spoed en ʼn lae landings gradiënt.

Orientador: José Roberto Cury Saad / Resumo: Buscando o melhor entendimento sobre as forças oclusais que influenciam diretamente na longevidade dos materiais fresados em CAD/CAM, tecidos e, consequentemente, tratamentos reabilitadores, este estudo pretende avaliar a distribuição de tensão mecânica em coroas implantossuportadas e na interface osso-implante, analisando de que maneira diferentes materiais de cobertura protética (dissilicato de lítio, resina composta e composto híbrido Enamic ) se comportam em situações clínicas simuladas com implantes curtos, utilizando a análise fotoelástica com observação e análise das franjas isocromáticas. Dois implantes hexágono externo de diâmetro 5 milímetros e comprimento de 5,5 e 13 milímetros foram incluídos cada um em um bloco de resina fotoelástica de dimensões 65 x 30 x 15 mm (largura, comprimento e profundidade), instalados coroas fresadas em CAD/CAM sendo uma de compósito, outra de cerâmica dissilicato de lítio e uma terceira de um composto cerâmico híbrido. Ao conjunto foi-se submetido uma força vertical de 10 N suficiente para gerar uma resposta mecânica na coroa. Foram colhidas imagens das franjas isocromáticas observadas em frente a um polaroscópio circular com o uso de uma câmera semi-profissional e os dados foram analisados em 5 pontos diferentes ao redor do implante de acordo com a intensidade de cor gerada pelas franjas isocromáticas. Após análise estatística não se observou diferença na dissipação de força na resina fotoelástica quando comparadas as diferentes coroa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In order to better understand the occlusal forces that directly influence the longevity of materials machined in CAD / CAM, tissues and, consequently, rehabilitation treatments, this study intends to evaluate the mechanical stress distribution in implant-supported crowns and the bone-implant interface, analyzing (Lithium disilicate, zirconium dioxide and Enamic hybrid compound) behave in simulated clinical situations with short implants using photoelastic analysis with observation and analysis of the isochromatic fringes. Two external hexagon implants with a diameter of 5 mm and a height of 5.5 and 13 mm were each included in a block of photoelastic resin of dimensions 65 x 30 x 15 mm (width, height and depth), installed crowns in CAD / CAM being one of composite, another of disilicate lithium ceramic and a third of a hybrid ceramic compound. A vertical force of 10 N was sufficient to generate a mechanical response on the resin. Images were taken from the isochromatic fringes observed in front of a circular polaroscope with the use of a semi-professional camera and the data were analyzed in 5 different points around the implant according to the color intensity generated by the isochromatic fringes. After statistical analysis, it was not observed a difference in force distribution on photoelastic resin when compared the different crowns tested, however when the comparison was made between short and long implant, a higher and statistically significant mechanical stress intensit... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2014-06-11T19:28:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-03-03Bitstream added on 2014-06-13T19:16:51Z : No. of bitstreams: 1 ribeiro_jgr_me_arafo.pdf: 3291389 bytes, checksum: 7433b8057e44c506b548538c7a3e997e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste estudo foi avaliar o efeito de três tratamentos superficiais na resistência de união de um cimento resinoso a três cerâmicas dentais: Duceram Plus (DP), IPS Empress II (IPS) e In-Ceram Alumina (INC), e analisar a topografia superficial dessas cerâmicas submetidas aos mesmos tratamentos superficiais. Para o teste de resistência de união foram confeccionadas 18 amostras de cada material (7,5mm de diâmetro x 3,0mm de espessura), incluídas em resina acrílica e polidas até lixa nº 600. As amostras foram divididas em três grupos: a) jateamento com partículas de óxido de alumínio de 50 æm; b) condicionamento com ácido fluorídrico 10%; c) associação de a e b. As amostras foram lavadas e secas. A área de adesão da cerâmica foi delimitada com matriz metálica perfurada (5,0mm de diâmetro e 3,0mm de espessura). Foi aplicado silano, adesivo e cimento resinoso Variolink II, fotoativado por 40 segundos. As amostras receberam 1000 ciclos térmicos de 5 a 55°C. O ensaio de cisalhamento foi realizado em máquina de ensaios MTS 810, com célula de carga de 10 kN e velocidade de 0,5 mm/min. Para a topografia superficial foram confeccionados um coping de IPS, um do INC e uma coroa de DP, seguindo as recomendações dos fabricantes. Cada coping ou coroa foi cortado com disco diamantado em quatro partes: uma delas não recebeu nenhum tratamento, e as demais receberam um dos tratamentos acima descritos. Fotomicrografias foram obtidas por meio de microscopia eletrônica de varredura e a análise foi feita de acordo com a característica da superfície. Pode-se concluir que: o tratamento associado não ofereceu vantagens em relação ao condicionamento ácido, para os materiais DP e IPS; para o INC o tratamento associado não ofereceu vantagens em relação ao jateamento. A DP e o IPS apresentaram resultados melhores em relação ao INC, independentemente dos tratamentos... / The aim of this study was to evaluate the effect of three surface treatments on the shear bond strength of a resin luting cement to three ceramics materials: Duceram Plus (DP), IPS Empress II (IPS) and In-Ceram Alumina (INC), and to assess its surface topography after these treatments. Eighteen specims were fabricated to each material (7,5 mm in diameter x 3,0 mm in thickness), embebed in acrylic resin and ground up to 600 grit. The specims were randomly divided into 3 groups of 6 specims: (a) airborne particle abrasion with 50 æm aluminum oxide; (b) 10% hydrofluoric acid etching; (c) a and b treatments. The specims were cleaned and dried. Silane, adhesive and resin luting cement Variolink were applied in 5,0 mm in diameter and 3,0 mm height to ceramic surface and then light cured. All specims were termocycled (1000, 5-55°C). The shear bond strength was then measured in a testing machine MTS 810, at a crosshead speed of 0,5 mm/min. To asses the surface topography, one coping each of IPS and INC, and a DP crown were fabricated following the manufacturer's instructions. Each coping or crown was sectioned into 4 equal parts by a diamond disk. One part didn't receive any treatment, and the others, received treatments as above described. Photomicrographs were obtained by a SEM, and the superficial characteristic was described. In conclusion, the associate treatment didn't offer advantages in relation to the acid etching, for DP and IPS; for INC the associate treatment didn't offer advantages in relation to the airborne. DP and IPS presented the best results, independently of the superficial treatments. The photomicrographs showed compatible correlation of the superficial characteristic with the bond strength values.

Made available in DSpace on 2015-03-03T11:52:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-18Bitstream added on 2015-03-03T12:06:08Z : No. of bitstreams: 1 000795787.pdf: 571234 bytes, checksum: f635d0ca5e8e957bf53c65ab8998057a (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Objetivo: O objetivo deste estudo foi avaliar a adaptação marginal de infraestruturas de próteses fixas confeccionadas pelo Sistema CAD/CAM com três diferentes sistemas de aquisição de dados. Material e Métodos: Confeccionaram-se 50 corpos de prova; Convencional (Ni-Cr) (n = 10), GI: iTero (n = 10), GII: CerecBluecam/fresadora industrial (n = 10), GIII: 3S (n = 10) e GIV: CerecBlueCam/Sirona (n = 10). Os corpos de prova foram numerados e randomizados, realizou-se análise da desadaptação marginal vertical. Resultados: A análise intra observador indicou que não houve diferença estatisticamente significante (teste t pareado, p = 0.822) no período antes e depois das análises. O sistema convencional (321 ?m) apresentou maior desadaptação quando comparado com o sistema CAD/CAM (89 ?m) (p<0.001). O sistema intra oral (iTero) apresentou menor índice de desadaptação marginal, quando comparado com o sistema extra oral (3S), (p<0.001). O sistema aberto apresentou maior índice de desadaptação marginal (114 ?m) quando comparado com intra oral (iTero), sendo p<0.001. Além disto, no sistema convencional, observou-se que os pré-molares apresentaram índice de desadaptação maior quando comparado (361 ?m) com o molar (283 ?m) (p<0.001), porém no sistema CAD/CAM não houve diferença estatisticamente significante na comparação de dentes pré-molares (93,7 ?m) e molares (84,9 ?m). Significância: O sistema CAD/CAM pode atuar mais favoravelmente, reduzindo o índice de desadaptação marginal, quando comparado com o sistema convencional de confecção de próteses dentárias. O sistema intra oral (iTero) comportou-se melhor quando comparado com os demais sistemas. / Objective: The aim of this study was to evaluate the marginal fit of frameworks produced by CAD/CAM systems with three different data acquisition. Material and Methods: We fabricated 50 frameworks: conventional (Ni-Cr) (n = 10), GI:iTero (n = 10), GII:CerecBluecam/industrial milling (n = 10), GIII:3S (n = 10), and GIV:CerecBlueCam/Sirona (n = 10). We numbered the specimens and analyzed them randomly. Results: Intra-observer analysis indicated no statistically significant difference (paired t-test, p = 0.822) before and after the analysis. The conventional system (321 ?m) showed greater misfit than the CAD/CAM (89 ?m) (p<0.001) system. The intraoral system (iTero) showed a lower rate of marginal misfit than the extra-oral system (3S), (p<0.001). The open system presented a higher marginal discrepancy (114 ?m) than intraoral (iTero), with p<0.001. Moreover, in the conventional system, premolars (361 ?m) showed a higher index of misfit than molars (283 ?m) (p<0.001), but for the CAD/CAM system, there was no statistically significant difference between premolars (93.7 ?m) and molars (84.9 ?m). Significance: The CAD/CAM system can to act more favorably reducing the rate of marginal discrepancy than the conventional impression system of dental prosthesis. The intra oral system (iTero) was better than other systems. / FAPESP: 11/06311-5