"2009" / Thesis (MSc (Hons))--Macquarie University, Faculty of Science, Dept. of Physics and Engineering, 2010. / Bibliography: p. 163-166. / Introduction -- Design theory and process technology -- 15GHz oscillator implementations -- 24GHz oscillator implementation -- Frequency prescaler implementation -- MMIC fabrication and measurement -- Conclusion. / Advances in Silicon Germanium (SiGe) Bipolar Complementary Metal Oxide Semiconductor (BiCMOS) technology has caused a recent revolution in low-cost Monolithic Microwave Integrated Circuit (MMIC) design. -- This thesis presents the design, fabrication and measurement of four MMICs for frequency synthesis, manufactured in a commercially available IBM 0.18μm SiGe BiCMOS technology with ft = 60GHz. The high speed and low-cost features of SiGe Heterojunction Bipolar Transistors (HBTs) were exploited to successfully develop two single-ended injection-lockable 15GHz Voltage Controlled Oscillators (VCOs) for application in an active Ka-Band antenna beam-forming network, and a 24GHz differential cross-coupled VCO and 1/6 synchronous static frequency prescaler for emerging Ultra Wideband (UWB) automotive Short Range Radar (SRR) applications. -- On-wafer measurement techniques were used to precisely characterise the performance of each circuit and compare against expected simulation results and state-of-the-art performance reported in the literature. -- The original contributions of this thesis include the application of negative resistance theory to single-ended and differential SiGe VCO design at 15-24GHz, consideration of manufacturing process variation on 24GHz VCO and prescaler performance, implementation of a fully static multi-stage synchronous divider topology at 24GHz and the use of differential on-wafer measurement techniques. -- Finally, this thesis has llustrated the excellent practicability of SiGe BiCMOS technology in the engineering of high performance, low-cost MMICs for frequency synthesis in millimeterwave (mm-wave) devices. / Mode of access: World Wide Web. / xxii, 166 p. : ill (some col.)

Magister Commercii (Information Management) - MCom(IM) / No organisation has an endless and unlimited supply of money, especially in a recessive economy, and therefore decisions have to be made as to which areas an organisation will invest in. As organisations, such as YZ1 financial services organisation, are focused on seeing returns on investment (ROI), implementing software that is not being used will not render any benefits to the organisation. Research problem: Project Managers (PMs) in YZ organisation’s IT department need to perform mandated processes, as defined in their centralised repository. PMs need to use Financial and Planning Software (FPS)2 software to perform certain project management activities, as required by their job function. However, it was found that MPP3 software, another tool, was used for more detailed project schedules, as well as activities that were not strictly enforced by management, the Project Office or the Quality Assurance team. Therefore, from this discovery, it was not clear whether the intended benefit of implementing this mandatory software (FPS) was being realised – since implementing software that is not being utilised fully would not deliver the intended benefits to the IT department (Devaraj & Kohli 2003), even if the software is termed ‘mandatory’. Objective: The primary objective of this research was to explore and optimise the key success factors for an effective implementation of mandatory software in a department, in order to derive the intended business benefits. Literature Review: Literature was reviewed in the search for models or theories that explore the relationship between the use of mandatory software and the achievement of business benefits. The Information Management Body of Knowledge (IMBOK) was selected as this framework defines the relationship between IT and the realisation of business benefits, and ultimately the achievement of any business strategy. The literature review focused predominantly on the level of user involvement, change management, as well as factors that influence the usage of mandatory software by individuals. 1. The name of the organisation utilised has been changed. Refer to Ethical Consideration 2. The name of the tools utilised has been changed. Refer to Ethical Consideration and list of acronyms 3. The name of the tools utilised has been changed. Refer to Ethical Consideration and list of acronyms. Focus was given to organisational factors affecting usage, such as top management support and organisational processes. A model was compiled using unique constructs in the Technology Acceptance Model (and TAM2), the Motivational Model (MM) and the Model of PC Utilisation (MPCU) – in order to test user acceptance of mandatory software. The literature study concludes with a review of an approach to benefits management including five stages, namely: identifying and structuring benefits, planning for the realisation of benefits, executing the plan, in addition to the evaluation and the review. Research design and methodology: A case study was used in this research, as it examined the phenomenon in its natural setting, employing multiple methods of data collection to gather information from a few entities (groups and data sources). In this way, it was not limited to only qualitative or quantitative approaches, but utilised mixed methods instead. A mixed methods approach was used in order to elaborate, enhance and clarify the results from the qualitative research through the results of the quantitative analysis. Findings: The main finding, based on the compilation of three models of user acceptance, proved that FPS was not being utilised as intended. There was also no evidence of an improvement in business operations. Therefore, benefits management was negatively impacted. Organisational processes were dentified as the most important organisational factor, influencing the usage of FPS software. Own technological capability was considered to be the least important factor, as respondents believed that they had sufficient IT skills in order to learn how to use FPS software. Change management was rated negatively; and as a result, it impacted the usage of FPS, as users were not involved in the decision to implement, and had limited interaction in the implementation process. In addition, there was no evidence found that benefits management was conducted in the IT department; and therefore, the impact of using alternative software could not be quantitatively assessed. Recommendations: In concluding this research, it is recommended that the “best practice”, derived from the pertinent literate should be followed more diligently if YZ organisation is to benefit from the implementation of mandatory software. For example, in this research, it was found that top management’s support of FPS (second most important organisational factor influencing use) was lacking, despite the literature suggestion that senior management involvement in changing technology is crucial for organisational commitment. It is suggested that a more formal approach to benefits management should be implemented. It is also recommended that further study should be conducted – in order to explore the applicability of the Japanese framing (achieving benefits from IT software through the concept of strategic instinct, rather than strategic alignment) in the context of a developing country (such as South Africa). / South Africa

Magister Commercii (Information Management) - MCom(IM) / No organisation has an endless and unlimited supply of money, especially in a recessive economy, and therefore decisions have to be made as to which areas an organisation will invest in. As organisations, such as YZ1 financial services organisation, are focused on seeing returns on investment (ROI), implementing software that is not being used will not render any benefits to the organisation.Research problem: Project Managers (PMs) in YZ organisation’s IT department need to perform mandated processes, as defined in their centralised repository. PMs need to use Financial and Planning Software (FPS)2 software to perform certain project management activities, as required by their job function. However, it was found that MPP3 software, another tool, was used for more detailed project schedules, as well as activities that were not strictly enforced by management, the Project Office or the Quality Assurance team.Therefore, from this discovery, it was not clear whether the intended benefit of implementing this mandatory software (FPS) was being realised – since implementing software that is not being utilised fully would not deliver the intended benefits to the IT department (Devaraj & Kohli 2003), even if the software is termed ‘mandatory’.Objective: The primary objective of this research was to explore and optimise the key success factors for an effective implementation of mandatory software in a department, in order to derive the intended business benefits.Literature Review: Literature was reviewed in the search for models or theories that explore the relationship between the use of mandatory software and the achievement of business benefits. The Information Management Body of Knowledge (IMBOK) was selected as this framework defines the relationship between IT and the realisation of business benefits, and ultimately the achievement of any business strategy.The literature review focused predominantly on the level of user involvement, change management, as well as factors that influence the usage of mandatory software by individuals.1 The name of the organisation utilised has been changed. Refer to Ethical Consideration 2 The name of the tools utilised has been changed. Refer to Ethical Consideration and list of acronyms 3 The name of the tools utilised has been changed. Refer to Ethical Consideration and list of acronyms Focus was given to organisational factors affecting usage, such as top management support and organisational processes. A model was compiled using unique constructs in the Technology Acceptance Model (and TAM2), the Motivational Model (MM) and the Model of PC Utilisation (MPCU) – in order to test user acceptance of mandatory software.The literature study concludes with a review of an approach to benefits management including five stages, namely: identifying and structuring benefits, planning for the realisation of benefits, executing the plan, in addition to the evaluation and the review.Research design and methodology: A case study was used in this research, as it examined the phenomenon in its natural setting, employing multiple methods of data collection to gather information from a few entities (groups and data sources). In this way, it was not limited to only qualitative or quantitative approaches, but utilised mixed methods instead. A mixed methods approach was used in order to elaborate, enhance and clarify the results from the qualitative research through the results of the quantitative analysis.Findings: The main finding, based on the compilation of three models of user acceptance, proved that FPS was not being utilised as intended. There was also no evidence of an improvement in business operations. Therefore, benefits management was negatively impacted. Organisational processes were identified as the most important organisational factor, influencing the usage of FPS software. Own technological capability was considered to be the least important factor, as respondents believed that they had sufficient IT skills in order to learn how to use FPS software.Change management was rated negatively; and as a result, it impacted the usage of FPS, as users were not involved in the decision to implement, and had limited interaction in the implementation process. In addition, there was no evidence found that benefits management was conducted in the IT department; and therefore, the impact of using alternative software could not be quantitatively assessed.Recommendations: In concluding this research, it is recommended that the “best practice”,derived from the pertinent literate should be followed more diligently if YZ organisation is to benefit from the implementation of mandatory software. For example, in this research, it was found that top management’s support of FPS (second most important organisational factor influencing use) was lacking, despite the literature suggestion that senior management involvement in changing technology is crucial for organisational commitment.It is suggested that a more formal approach to benefits management should be implemented. It is also recommended that further study should be conducted – in order to explore the applicability of the Japanese framing (achieving benefits from IT software through the concept of strategic instinct, rather than strategic alignment) in the context of a developing country (such as South Africa).

This thesis analyzes and defines requirements of framework, which helps with quick and effortless development of business information systems. The main goal of the framework is development acceleration, price reduction and overall improvement of product quality. The thesis also compares and evaluates existing tools. The result is detailed design and implementation of own flexible solution that fulfills all defined requirements and removes disadvantages of existing solutions. In the scope for further studies framework development possibilities and directions are listed.

A 5 GHz continuous unlicensed bandwidth is available at millimeter-wave (mm-wave) frequencies around 60 GHz and offers the prospect for multi gigabit wireless applications. The inherent atmospheric attenuation at 60 GHz due to oxygen absorption makes the frequency range ideal for short distance communication networks. For these mm-wave wireless networks, the low noise amplifier (LNA) is a critical subsystem determining the receiver performance i.e., the noise figure (NF) and receiver sensitivity. It however proves challenging to realise high performance mm-wave LNAs in a silicon (Si) complementary metal-oxide semiconductor (CMOS) technology. The mm-wave passive devices, specifically on-chip inductors, experience high propagation loss due to the conductivity of the Si substrate at mm-wave frequencies, degrading the performance of the LNA and subsequently the performance of the receiver architecture. The research is aimed at realising a high performance mm-wave LNA in a Si BiCMOS technology. The focal points are firstly, the fundamental understanding of the various forms of losses passive inductors experience and the techniques to address these issues, and secondly, whether the performance of mm-wave passive inductors can be improved by means of geometry optimising. An associated hypothesis is formulated, where the research outcome results in a preferred passive inductor and formulates an optimised passive inductor for mm-wave applications. The performance of the mm-wave inductor is evaluated using the quality factor (Q-factor) as a figure of merit. An increased inductor Q-factor translates to improved LNA input and output matching performance and contributes to the lowering of the LNA NF. The passive inductors are designed and simulated in a 2.5D electromagnetic (EM) simulator. The electrical characteristics of the passive structures are exported to a SPICE netlist which is included in a circuit simulator to evaluate and investigate the LNA performance. Two LNAs are designed and prototyped using the 13μ-m SiGe BiCMOS process from IBM as part of the experimental process to validate the hypothesis. One LNA implements the preferred inductor structures as a benchmark, while the second LNA, identical to the first, replaces one inductor with the optimised inductor. Experimental verification allows complete characterization of the passive inductors and the performance of the LNAs to prove the hypothesis. According to the author's knowledge, the slow-wave coplanar waveguide (S-CPW) achieves a higher Q-factor than microstrip and coplanar waveguide (CPW) transmission lines at mm-wave frequencies implemented for the 130 nm SiGe BiCMOS technology node. In literature, specific S-CPW transmission line geometry parameters have previously been investigated, but this work optimises the signal-to-ground spacing of the S-CPW transmission lines without changing the characteristic impedance of the lines. Optimising the S-CPW transmission line for 60 GHz increases the Q-factor from 38 to 50 in simulation, a 32 % improvement, and from 8 to 10 in measurements. Furthermore, replacing only one inductor in the output matching network of the LNA with the higher Q-factor inductor, improves the input and output matching performance of the LNA, resulting in a 5 dB input and output reflection coefficient improvement. Although a 5 dB improvement in matching performance is obtained, the resultant noise and gain performance show no significant improvement. The single stage LNAs achieve a simulated gain and NF of 13 dB and 5.3 dB respectively, and dissipate 6 mW from the 1.5 V supply. The LNA focused to attain high gain and a low NF, trading off linearity and as a result obtained poor 1 dB compression of -21.7 dBm. The LNA results are not state of the art but are comparable to SiGe BiCMOS LNAs presented in literature, achieving similar gain, NF and power dissipation figures. / Dissertation (MEng)--University of Pretoria, 2012. / Electrical, Electronic and Computer Engineering / unrestricted

[ES] La creciente preocupación sobre el efecto de la emisión de gases nocivos provenientes de motores de combustión interna alternativos (ICE) a la atmósfera ha llevado a los gobiernos a lo ancho del planeta a limitar la cantidad de dichas emisiones, particularmente en Europa a través de las normas EURO. La dificultad en cumplir dichas limitaciones ha llevado a la industria automovilística a cambiar el foco de motores de encendido por compresión (CI) o provocado (SI) hacia la electrificación o los combustibles libres de carbono. Sin embargo, esta transición no se puede llevar a cabo de manera sencilla en el corto y medio plazo, mientras que combustibles libres de carbono como el Hidrógeno (H2 ) o el Amoniaco (NH3 ) siguen produciendo algunos contaminantes como los Óxidos de Nitrógeno (NOx ), con los cuales hay que lidiar. Estas emisiones pueden ser particularmente dañinas para el ser humano ya que incrementan el riesgo de cáncer de pulmón. La Reducción Catalítica Selectiva (SCR) ha demostrado ser una tecnología eficaz para la reducción de este contaminante en particular. A través de una inyección de una Solución de Urea-Agua, junto con la energía térmica de los gases de escape, se genera una cantidad suficiente de NH 3 capaz de neutralizar los indeseados NOx en un catalizador de reducción. Con la inclusión de los SCR en automóviles ligeros además de su presencia tradicional en automóviles pesados, los SCR han sido el foco de la comunidad científica para mejorar el entendimiento de su principio de actuación, y mejorar su eficiencia en un entorno legislativo en el que los limites de emisión se han estrechado enormemente. Esta Tesis intenta ser parte de ese esfuerzo científico en caracterizar el proceso de inyección de UWS en su totalidad a través de un entorno computacional. El presente estudio tiene como objetivo proveer de un mejor entendimiento del proceso de atomización y degradación sufrido por los chorros de UWS. Las dinámicas no estacionarias que se dan lugar en la zonas cercana del chorro, añadido a la gran influencia de las características internas del inyector sobre el desarrollo del spray hacen que los métodos experimentales sean complicados para poder entender dicho proceso. Por otro lado, la Mecánica de Fluidos Computacional (CFD) presenta una alternativa. Para el propósito de esta Tesis, el CFD ha sido utilizado para caracterizar los sprays de SCR. Se intenta desarrollar y seleccionar los modelos más apropiados a chorros de baja velocidad, y establecer un conocimiento Una vez adquiridos dichos métodos, los mecanismos principales de rotura del chorro y de degradación de la urea se han analizan. En ese sentido, el uso de técnicas experimentales podrían ser sustituídos en el futuro para esta aplicación. Los métodos CFD son validados tanto en el campo cercano como en el lejano. Para el campo cercano, el tratamiento multi-fase se lleva a cabo a través de métodos de Modelo de Mezclas, o el método Volume-Of-Fluid. A través de ellos, la caracterización hidráulica de dos reconstrucciones del inyector de UWS se lleva a cabo. Subsiguientes análisis se llevan a cabo sobre las dinámicas de rotura de la vena líquida, descubriendo que mecanismos rigen el proceso. El estudio de campo lejano usa un Discrete Droplet Model (DDM) para lidiar con las fases líquidas y gaseosas. En él, la evaporación del agua y el proceso de termólisis de la urea han sido considerados y comparados con resultados experimentales con el fin de obtener una metodología fiel para su caracterización. Todo el conocimiento adquirido se aplica más tarde a un Close-Coupled SCR, en el cual condiciones de trabajo realista han sido consideradas. Además, una herramienta llamada Maximum Entropy Principle (MEP) es presentada. Por tanto, esta Tesis aporta una metodología valiosa capaz de predecir tanto el campo cercano como el lejano de chorros de UWS de una manera precisa. / [CA] La creixent preocupació sobre el efecte de l'emissió de gasos nocius provenients the motors de Combustió Interna Alternatius (ICE) a l'atmosfera ha dut als governs de tot el planeta a limitar la quantitat d'aquestes emisions, particularment a Europa mitjant les normes EURO. La dificultat de complir aquestes limitacions ha portat a l'industria automovilística a cambiar el focus de motors d'encedut per compresió (CI) o provocat (SI) cap a la electrificació o els combustibles lliures de carbó. No obstant això, aquesta transició no es pot dur a terme de manera senzilla , mentres que els combustibles lliures de carbó como l'Hidrogen (H2 ) o l'Amoniac (NH3 ) seguirien produint contaminants como els Óxids de Nitrogen (NOx ), amb els quals n'hi ha que bregar. Estes emissions poden ser particularment nocives per a l'esser humà ja que incrementen el risc de càncer de pulmó. La Reducció Catalítica Selectiva (SCR) ha demostrat ser una tecnología eficaç per a la reducció d'este contaminant en particular. Mitjançant una injecció d'una Solució D'Urea i Aigua, junt a l'energía térmica dels gasos d'fuita, es pot generar una quantitat suficiente de NH 3 capaç de neutralitzar els indesitjats NO x a un catalitzador de reducció. Amb l'inclusió dels SCR en automòvils lleugers a més de la seua tradicional presència en automòvils pesats, els SCR han segut el foc per a mijorar l'enteniment del seu principi d'actuació, i mijorar la seua eficiencia. Este estudi té como a objectiu proveir d'un mijor entenement del procés d'atomizació y degradació patit pels dolls de UWS. Les dinàmiques no estacionaries que es donen lloc en la zona propenca al doll, afegit a la gran influència de les característiques internes del injector sobre el desentroll de l'esprai, fan que els métods experimentals siguen complicats d'aplicar per entendre dit procés. Per un altre costat, la Mecànica de Fluïts Computacional (CFD) supon una alternativa que té certes avantatges. Per al propòsit d'esta Tesi, el CFD ha sigut utilitzat com la principal metodología per a caracteritzar elsesprais de SCR. Per mitjà de dits métodes, la Tesi vol desentrollar i seleccionar els models més apropiats que mitjos s'adapten a sprays de baixa velocitat, i establir un coneiximent per a posteriors estudis desentrollats sobre la mateixa temàtica. Una volta adquirits dits métodes, els mecanismes principals de trencament del doll, així com els de degradació de l'urea en amoníac s'analitzaran. En aquest sentit, l'us de técniques experimentals podría no ser utilitzat més en el futur per aquesta aplicació.Els métods CFD son aplicats i validats tant el el camp propenc com en el llunyà. Per al camp propenc, el tractament multi-component es porta a terme a través de métodes Eulerians-Eulerians, com el Model de Mescles, o el métode Volume-Of-Fluid. La caracterització hidràulica de dos reconstruccions de l'injector es porta a terme, els resultats del qual són comparats amb resultats experimentals. Subsegüents anàlisis es porten a terme sobre les dinàmiques de trencament de la vena líquida, descobrint qué mecanismes regeixen el procés. L'estudi de camp llunyà usa un Discrete Droplet Model (DDM) per a bregar en la fase líquida i gaseosa. En ell, l'evaporació del aigua y el procés de termòlisis de l'urea han sigut considerats i comparats amb el resultats experimentals amb la finalitat d'obtindre una metodología fidel per a la seua caracterització. Tot el coneixement obtingut s'aplica més tard a un Close-Coupled SCR, en el qual condicions de treball realistes han sigut considerades. Dels resultats obtinguts dels distints estudis, una ferramenta adicional anomenada Maximum Entropy Principle (MEP),capaç de predir el fenomen d'atomització dels doll de UWS sense la necessitat de realitzar simulacions del camp propenc, es presentat. Per tant, esta Tesi aporta una metodología capaç de predir tant el camp proper como el llunyà d'una manera precisa. / [EN] The increasing awareness of the effect of emitting harmful gases from Internal Combustion Engines (ICE) into the atmosphere has driven the governments across the globe to limit the amount of these emissions, par ticularly in Europe through the EURO norms. The difficulty to meet such limitations has driven the automotive industry to shift from traditional Compression Ignited (CI) or Spark Ignited (SI) engines toward electrification or carbon-free fuels. Nonetheless, this transition will not be easily done in the short and medium time frames, while carbon-free fuels such as Hydrogen (H2 ) and Ammonia (NH3 ) will keep producing certain pollutants such as Nitrogen Oxides (NOx ) which need taking care of. These emissions can be particularly hazardous for humans, increasing the risk of developing lung cancer. Selective Catalytic Reduction (SCR) is an effective technology for reducing this specific ICE contaminant. An injection of a Urea-Water Solution (UWS), together with the thermal energy of the combustion gases can generate a sufficient amount of NH 3 capable of neutralizing the unwanted NO x in a catalyst. With the fitting of SCR systems within light-duty applications, in addition to their traditional presence on heavy-duty usage, SCR has been on the focus to understand their working principle and improve their efficiency . This Thesis tries to become part of that scientific ensemble by characterizing the whole UWS injection process within a computational framework. The present research aims to provide a better understanding of the atomizing and degradation processes undergone by the UWS sprays. The transient dynamics taking place in the near-field region, added to the great influence of the inner-injector characteristics on the development of the spray make experimental approaches on such sprays challenging in providing such knowledge. Computational Fluid Dynamics (CFD) provide an alternative that has certain advantages. For this Thesis they have been adopted as the main methodology on characterizing SCR sprays. The Thesis tries to develop and select the appropriate models that best suit low-velocity sprays. With the suitable methods that best predict these sprays, the main jet breakup mechanisms, together with the urea-to-ammonia transformation will have their behavior analyzed. In that way, experimental techniques could be avoided for such applications. CFD is applied and validated both in the near-field and far-field regions. For the near-field, multi-component flows are treated through Eulerian-Eulerian such as the Mixture Model or the Volume-Of-Fluid method. Through them, a hydraulic characterization on two recon structions of the UWS injector is performed, with results compared with experimental data. Further analysis is done on the jet-to-droplet dynamics, assessing which mechanisms drove the process. The far-field analy sis uses a Discrete Droplet Model (DDM) for dealing with the gas and liquid phases. In it, the evaporation of water and the thermolysis process of the urea have been considered and again compared with experimental results to have a faithful methodology for its characterization. All the acquired knowledge has been later applied to a commercial Close-Coupled SCR, in which real-working conditions have been considered. From the results obtained from several studies, an additional tool called Maximum Entropy Principle (MEP), capable of predicting the UWS spray atomization phenomenon without the need to perform near-field simulations, has been provided. Accordingly, this Thesis provides a valuable methodology capable of predicting the near-field and far-field dynamics accurately thanks to its validation against experimental results from literature. Additionally, the MEP tool can be used independently for computational and experimental works to predict the performance of UWS atomizers.The work carried out presents a significant leap in the application of CFD tools in predicting low-velocity sprays. / Javier Marco Gimeno has been founded through a grant from the Government of Generalitat Valenciana with reference ACIF/2020/259 and financial support from the European Union. These same institutions, Government of Generalitat Valenciana and The European Union, supported through a grant for pre-doctoral stays out of the Comunitat Valenciana with reference CIBEFP/2021/11 the research carried out during the stay at Energy Systems, Argonne National Laboratory, United States of America. / Marco Gimeno, J. (2023). Computational study of Formation and Development of Liquid Jets in Low Injection Pressure Conditions. Focus on urea-water solution injection for exhaust gas aftertreatment [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/198699

Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this study was to evaluate the fracture resistance of three post and core systems in endodontically treated teeth by loading to failure, and to measure marginal gaps before and after cyclic loading. Sixty extracted canines were assigned to three groups. The groups tested were: 1) Single cast post and core (Group CP). 2) Prefabricated metal post and composite resin core (Group MR). 3) Glass fiber post and composite resin core (Group FR). All teeth were obturated and prepared to receive a post and core with a coping. Thirty teeth (10 from each group) were loaded to failure, and the other 30 teeth were fatigue-loaded. The marginal gaps on the facial and lingual surface of the fatigue-loaded group were measured before and after cyclic loading. There were two hypotheses for this study. The first was that the FR group would have less marginal gap opening on the lingual surface than the other groups. The second was that the CP group would have a higher load at failure than the other groups. Group CP was found to have a significantly smaller pre-loading marginal gap than group FR (p = 0.0265) and group MR (p = 0.0273), while groups FR and MR did not have a significantly different pre-loading marginal gaps (p = 0.86). Group FR had significantly less change in marginal gap than group MR (p = 0.0013). Groups CP and MR did not have significantly different changes in marginal gap (p = 0.09). Groups CP and FR did not have significantly different changes in marginal gap (p = 0.11). The three post types did not have significantly different maximum loads to failure (p= 0.49), moments of inertia at cervical area (p = 0.75), or moments of inertia at fracture site (p=0.12). There was no significant difference between groups CP, FR, and MR in the load-to-failure test. Group CP demonstrated the highest load-to-failure values; however, the highest load-to-failure mean was for group MR. All fractures observed in this study were catastrophic. Group FR demonstrated better stress distribution and caused no early fractures in the fatigue-loading group. All groups demonstrated significant marginal gap changes on the lingual surface after fatigue loading; however, group FR demonstrated <45 μm marginal gap opening. In group FR, the reduced marginal gap opening was attributed to the use of Panavia 21 with the proper surface treatments to bond to the tooth structure, the resin composite, and the metal coping.

Tato práce se se zabývá návrhem kinematiky zavěšení kol obou náprav. Na základě analýz jízdních dat, multi-body simulací v softwaru Adams Car, simulací v Matlabu a analytických kalkulací v Mathcadu, je navržena řada změn s cílem zlepšit jízdní vlastnosti vozu Formule student, tyto změny jsou následně implementovány do CAD modelu vozu. Jednotlivé změny kinematiky náprav jsou provedeny na základě analýzy konkrétního problému, který se snaží řešit. Jednou z problematik je zástavbová náročnost systému odpružení a zavěšení zadních kol, zde je cílem snížit hmotnost, výšku těžiště a moment setrvačnosti. Další problematikou je geometrie předního kola, kde je cílem zlepšit využití pneumatik a snížit síly v řízení. Dále se práce zabývá simulacemi elastokinematiky zadní nápravy, součástí je také návrh měřícího zařízení. V poslední části je zkoumán vliv provedených změn i elastokinematiky na jízdní dynamiku vozu v ustálených stavech za pomocí MM metody simulované s modelem celého vozu v Adams Car a zpracované v Matlabu.

utilization of current structures, concrete buildings, system of concrete buildings T06B, spank, portative parts of the structure, structure modifications, model of the solution

O controle da extrusão apical durante a reintervenção endodôntica é essencial para o sucesso do novo tratamento. Nesse contexto, o presente estudo teve como objetivo comparar a quantidade de material sólido extruído na desobturação de canais radiculares variando-se a técnica de esvaziamento e o limite de obturação. Foram utilizados 40 incisivos inferiores previamente tratados divididos em dois grupos de acordo com o limite de obturação estabelecido. Cada grupo foi subdividido em dois subgrupos levando-se em conta a técnica de desobturação empregada; manual (subgrupos A1 e B1) e mecânico-rotatória com limas de Ni-Ti (Quantec LX) (subgrupos A2 e B2). O material sólido extruído foi coletado por meio do sistema de filtração Millipore, levado à secagem em dessecador de sílica e pesado em balança analítica de precisão. Os resultados obtidos foram submetidos a ANOVA para dois fatores de variação sendo em seguida empregado o Teste de Tukey (&#945; = 5%). A técnica de desobturação mecânico-rotatória produziu menor extrusão (0,66mg) que a manual (1,11mg), havendo diferença estatística significante entre elas (p < 0,05). Os canais preenchidos até o vértice radiográfico apresentaram maior quantidade de extrusão (1,38mg) do que os obturados 1 mm aquém do forame (0,39mg), observando-se diferença estatística significante entre eles (p < 0,05). A menor quantidade extrusão foi observada no subgrupo A2 (0,20mg), em que foi empregada a técnica rotatória de desobturação em canais obturados 1mm aquém do forame apical, sendo constatada diferença estatisticamente significante deste subgrupo com os demais (p < 0,05). A extrusão de material sólido durante a desobturação de canais radiculares é influenciado pela técnica empregada e pelo limite apical de obturação. / The apical extrusion control during the endodontic retreatment is essential for the success of the new treatment. The purpose of this study was to compare the quantity of solid apically extruded material during filling removal according the gutta-percha removal technique and root filling limit. Forty mandibular incisors with a single straight canal were selected. The canals were previously endodontically treated and then divided into two groups according the filling level. Each group was subdivided in two groups considering the retreatment technique: stainless steel hand files (subgroups A1 and B1) versus niquel-titanium rotatory instruments (subgroups A2 and B2). The extruded solid material was collected by Millipore filtration system, dried in silica desiccators and weighed in an eletrobalance. The results were analyzed using ANOVA with two variation factors and Tukey Test (&#945; = 5%). The niquel-titanium rotatory instruments produced less extrusion (0,66mg) than the stainless steel hand files (1,11mg), with significant statistical difference between them (p < 0,05). The canals filled until the radiographic apex showed larger amount of extruded material (1,38mg) than those filled 1 mm beyond the foramen (0,39mg). It was observed significant statistical difference between them (p < 0,05). The smaller extruded debris amount was observed in subgroup A2 (0,20mg), in which one the rotary technique was used to remove the gutta-percha of canals filled 1mm beyond the apical foramen. It was verified significant statistical difference of this subgroup with the other ones (p < 0,05). The extrusion of solid material during the gutta-percha removal is influenced by the technique as well as the apical filling limit.