No description available.

No description available.

No description available.

No description available.

Syfte: Syftet med föreliggande in-vitro-studie är att utvärdera brotthållfastheten av singelkronor utformade som en central överkäksincisiv framställda av monolitisk högtranslucent Y-TZP, buckalt porslinsskiktad underkonstruktion av translucent Y-TZP eller monolitisk litiumdisilikatbaserad glaskeram. Material och metod: Sexton monolitiska kronor av högtranslucent Y-TZP framställdes med CAD/CAM-teknik, Coprasmile®(HTW) och Prettau® Anterior®(HTZ). Sexton kronor av translucent Y-TZP med buckal porslinspåbränning framställdes med CAD/CAM-teknik och manuell porslinsuppläggning, Copran HT®(LTW) och Prettau® Zircon(LTZ). Åtta monolitiska kronor av litiumdislikatbaserad glaskeram framställdes med pressteknik, IPS e.max® Press(LD). Samtliga kronor genomgick termocykling före cementering till stansar. Därefter genomgick kronorna cyklisk mekanisk förbelastning innan de frakturerades i en universal testmaskin. Resultat: Kronorna av translucent Y-TZP med buckal porslinyta visade högst brotthållfasthetsvärde. Gruppen LTW visade signifikant högre brotthållfasthetsvärde jämfört med de andra grupperna: HTW, HTZ, LTZ och LD. Slutsats: Fortsatt utveckling av testmetod för kronor utformade som incisiver är nödvändigt för att öka förståelsen kopplat till material, utformning av ersättning och testmetod med klinisk relevans. Det finns behov av vidare studier för högtranslucent Y-TZP samt semimonolitiska kronor av translucent Y-TZP. Beroende på materialval och kronutformning visades skillnader, men med studiens begränsningar kan ingen generell slutsats dras gällande brotthållfastheten. / Purpose: The purpose of this in-vitro-study is to evaluate the fracture resistance between high translucent monolithic Y-TZP, translucent Y-TZP with buccal porcelain veneering and monolithic lithium disilicate based glass-ceramic, designed as a single central maxilla crown. Material and method: Sixteen monolithic high translucent Y-TZP crowns were fabricated using CAD/CAM technique, Coprasmile®(HTW) and Prettau® Anterior®(HTZ). Sixteen crowns of translucent Y-TZP and buccal porcelain veneering were fabricated using CAD/CAM technique and manually layered porcelain, Copran HT®(LTW) and Prettau® zircon(LTZ). Eight monolithic crowns of lithium disilicate based glass-ceramic were fabricated using pressing techniques, IPS e.max® Press(LD). All crowns underwent thermo cycling prior to cementation to dies. Subsequently all crowns were subjected to a cyclic mechanical preload before being exposed to load-to-fracture in a universal testing machine. Result: Translucent Y-TZP with buccal veneering showed the highest rupture strength amongst the groups. The group LTW showed significantly higher fracture strength compared to the other groups: HTW, HTZ, LTZ and LD. Conclusion: Further development of testing methods for anterior crowns are necessary to increase the understanding connected to materials, crown designs and test methods for clinical relevance. There is a need in further studies for high-translucent Y-TZP and semi monolithic crowns made of translucent Y-TZP. There showed differences depending on the choice of material and crown form, but within the limitation of this study, no general conclusion can be drawn regarding the fracture strength.

A low-cost, low-temperature packaging concept is proposed for localized sealing and control of the ambient of a device cavity appropriate for Radio-Frequency (RF) Micro- Electro-Mechanical (MEMS) devices, such as resonators and switches. These devices require application specific packaging to facilitate their integration, provide protection from the environment, and control interactions with other circuitry. In order to integrate these devices into standard integrated circuit (IC) process flows and minimize damage due to post-fabrication steps, packaging is performed at the wafer level. In this work Indium and Silver are used to seal a monolithic localized hermetic pack- age. The cavity protecting the device is formed using standard lithography-based processing techniques. Metal walls are built up from the substrate and encapsulated by a glass or silicon lid to create a monolithic micro-hermetic package surrounding a predefined RF microsystem. The bond for the seal is then formed by rapid alloying of Indium and Silver using a temperature greater than that of the melting point of Indium. This ensures that the seal formed can subsequently function at temperatures higher than the melting temperature of pure Indium. This method offers a low-temperature bonding technique with thermal robustness suitable for wafer-level process integration. The ultimate goal is to create a seal in a vacuum environment. In this dissertation, design trade-offs made in wafer-level packaging are explained using thermo-mechanical stress and electrical performance simulations. Prototype passive microwave circuits are packaged using the developed packaging process and the performance of the fabricated circuits before and after packaging is analyzed. The effect of the package on coplanar waveguide structures are characterized by measuring scattering parameters and models are developed as a design tool for wafer-level package integration. The small scale of the localized package is expected to provide greater reliability over conventional full chip packages. / Ph. D.

This thesis presents the design, modeling, and development of adaptive robot hands that are capable of performing dexterous, in-hand manipulation. The robot hand comprises of anthropomorphic robotic fingers, which employ an adaptive actuation mechanism. The mechanism achieves both flexion/extension and adduction/abduction, on the finger's metacarpophalangeal joint, by using two actuators. Moment arm pulleys are employed to drive the tendon laterally, such that an amplification on the abduction motion occurs, while also maintaining the flexion motion. Particular emphasis has been given to the modeling and the analysis of the actuation mechanism. Also, a model for spatial motion is provided that relates the actuation modes with the finger motion and the tendon force with the finger characteristics. For the hand design, the use of differential mechanisms simplifies the actuation scheme, as we utilize only two actuators for four fingers, achieving affordable dexterity. A design optimization framework assess the results of hand anthropometry studies to derive key parameters for the bio-inspired actuation design. The model assumptions are evaluated with the finite element method. The proposed finger has been fabricated with the Hybrid Deposition Manufacturing technique and the actuation mechanism's efficiency has been validated with experiments that include the computation of the finger workspace, the assessment of the force exertion capabilities, the demonstration of the feasible motions, and the grasping and manipulation capabilities. Also, the hand design is fabricated with off-the-shelf materials and rapid prototyping techniques while its efficiency has been validated using an extensive set of experimental paradigms that involved the execution of grasping and in-hand manipulation tasks with everyday objects. / Master of Science / This thesis presents the design, modeling, and development of adaptive robot hands that are capable of performing selective interdigitation, robust grasping, and dexterous, in-hand manipulation. The robotic fingers employ an adaptive actuation mechanism. The design is minimal and the hand is capable of performing selective interdigitation, robust grasping, and dexterous, in-hand manipulation. Particular emphasis has been given to the modeling and the analysis of the actuation mechanism. For the hand design, the use of differential mechanisms simplifies the actuation scheme, as we utilize only two actuators for four fingers, achieving affordable dexterity. A design optimization framework assess the results of hand anthropometry studies to derive key parameters for the actuation design. The robotic fingers and the anthropomorphic hand were fabricated using off-the-self materials and additive manufacturing techniques. Several experiments were performed to validate the efficacy of the robot hand.

There has been increased interest in exploring high frequency (mm-wave) spectrum (particularly the 30 and 60 GHz ranges), and utilizing silicon-based technology for reduced-cost monolithic millimeter integrated circuits (MMIC), for applications such as WLAN, inter-vehicle communication (IVC) automotive radar and local multipoint distribution system (LMDS). Although there has been a significant increase in silicon-based implementations recently, this area still has significant need for research and development. For example, one microwave/mm-wave front-end component that has seen little development in silicon is the power amplifier (PA). Two potential technologies exist for providing a solution for low-cost microwave/mm-wave power amplifiers: 1) Silicon-Germanium (SiGe) HBT and 2) Complementary metal-oxide semiconductor (CMOS). SiGe HBT has become a viable candidate for PA development since it exhibits higher gain and higher breakdown voltage limits compared to CMOS, while remaining compatible with BiCMOS technology. Also, SiGe is potentially lower in cost compared to other compound semiconductor technologies that are currently used in power amplifier design. Hence, this research focuses on design of millimeter-wave power amplifiers in SiGe HBT technology. The work presented in this thesis will focus on design of different power amplifiers for millimeter-wave operating frequencies. Amplifiers present the fundamental trade-off between linearity and efficiency. Applications at frequencies highlighted above tend to be point-to-point, and hence high linearity is required at the cost of lowered efficiency for these power amplifiers. The designed power amplifiers are fully differential topologies based on finite ground coplanar waveguide (FGC) transmission line technology, and have on-chip matching networks and bias circuits. The selection and design of FGC lines is supported through full-wave EM simulations. Tuned single stub matching networks are realized using FGC technology and utilized for input and output matching networks. Two 30-GHz range SiGe HBT PA designs were carried out in Atmel SiGe2RF and IBM BiCMOS 8HP IC technologies. The designs were characterized first by simulations. The performance of the Atmel PA design was characterized using microwave/mm-wave on wafer test measurement setup. The IBM 8HP design is awaiting fabrication. The measured results indicated high linearity, targeted output power range, and expected efficiency performance were achieved. This validates the selection of SiGe HBT as the technology of choice of high frequency point-to-point applications. The results show that it is possible to design power amplifiers that can effectively work at millimeter-wave frequencies at lower cost for applications such as mm-wave WLAN and IVC where linearity is important and required transmitted power is much lower than in cellular handset power amplifiers. Moreover, recommendations are made for future research steps to improve upon the presented designs. / Master of Science

Yes / This paper presents an integrated model for shear friction strength of monolithic concrete interfaces derived from the upper-bound theorem of concrete plasticity. The model accounts for the effects of applied axial stresses and transverse reinforcement on the shear friction action at interfacial shear cracks. Simple equations were also developed to generalize the effectiveness factor for compression, ratio of effective tensile to compressive strengths and angle of concrete friction. The reliability of the proposed model was then verified through comparisons with previous empirical equations and 103 push-off test specimens compiled from different sources in the literature. The previous equations considerably underestimate the concrete shear transfer capacity and the underestimation is notable for the interfaces subjected to additional axial stresses. The proposed model provides superior accuracy in predicting the shear friction strength, resulting in a mean between experimental and predicted friction strengths of 0.97 and least scatter. Moreover, the proposed model has consistent trends with test results in evaluating the effect of various parameters on the shear friction strength.

Capillary electrochromatography (CEC) is a major capillary electrophoresis (CE) mode that have been interfaced to mass spectrometry (MS) for sensitive and selective analysis of chiral compounds. This research expands CEC applications in cancer biomarker and chiral CE analysis. Chapter 1 is a review of liquid chromatography-mass spectrometry (LC/MS), gas chromatography-mass spectrometry (GC/MS), and capillary electrophoresis mass spectrometry (CE/MS) for analysis of metabolites in prostate cancer diagnostics and therapies. In this chapter, a literature survey was performed within the databases PubMed, 4 Caplus/Webline and Web of Sciences. A total 17 studies reporting on various analytical platforms for metabolite identification in prostate cancer research, which often include case-control comparison were identified and reviewed. Chapter 2 described the analysis of metabolite biomarkers in prostate cancer tissues by capillary electrochromatography mass spectrometry. In this chapter, a capillary CEC–MS/MS method was developed for the simultaneous determination and separation of eight proofs of concept (POC) metabolites (betaine, malate, proline, N-acetyl aspartate, N-acetylglucosamine, uracil, xanthine, and alanine) as potential prostate cancer diagnostic markers. A polymeric monolith column with a hydrophilic crosslinker and strong anion-exchange mixed-mode has been fabricated by an in situ copolymerization of vinyl benzyl trimethylammonium chloride, and bisphenol A glycerolate dimethacrylate (BisGMA) in the presence of methanol and dodecyl alcohol as porogens and AIBN as initiator. After CEC separation, samples were analyzed by a triple–quadrupole mass spectrometer operated in positive ion mode. After optimization, the data showed that the CEC-MS/MS method using monolithic column achieved a much better chromatographic selectivity compared to coated columns and increased sensitivity than bare fused silica column The effect of mobile phase pH, ACN percentage and additive were studies. Under the optimum mobile phase conditions, this method was carried out to separate and detect eight metabolites in the biopsy sample. The LOD for the metabolites is between 50nM-100nM. This method has successfully used to examine patients’ prostate cancer with an accuracy of 95%. Chapter 3 demonstrates Insights into Chiral Recognition Mechanisms in CEC using linear salvation energy relationship. By varying the linker (amide and carbamate), head group (alanine, leucine, and valine) and chain length (C8, C10 and C12) of the amino acid bound surfactants; monolithic column was made to ultimately understand the factors governing chiral stationary solid phase. Through the comparison of system parameters, we can see that surfactant head group, linker and chain length affect the separation of achiral and chiral compounds. Also, with the same type surfactant, data was presented to show how the trend of LSER parameters and how it affects separation between in CEC. This study showed the predictive capability of LSER to understand the aforementioned intermolecular processes controlling retention and by doing so, be able to quantitatively predict the experimental conditions to achieve an acceptable chiral separation.