The findings of this PhD provide a significant contribution to early intervention research. The ability to detect those at ultra-high risk for psychosis (UHR) has been made possible in recent years. It is well known that people with serious mental illness have poor physical health, yet prior to this PhD little was known about the physical health of UHR individuals. This PhD explores the physical health and lifestyle of the UHR group, and makes recommendations for the development of a physical health intervention. A range of methods have been used including quantitative and qualitative methods, systematic reviews and meta-analyses, and a clinical audit. Therefore, a multifaceted approach to investigate the physical health and lifestyle of UHR individuals has been taken. Papers 1-3 suggest UHR individuals are more likely to live an unhealthy lifestyle than their peers. This includes lower levels of physical activity, and higher levels of substance use (generally cannabis, tobacco and alcohol). Paper 4 contains a clinical audit showing physical health and lifestyle factors are not monitored routinely in early detection services, despite the UHR phase being an ideal opportunity to intervene. Living an unhealthy lifestyle can have a detrimental effect on physical and mental health. Papers 1-4 emphasise the need to intervene to promote a healthy lifestyle for the UHR group. In line with the Medical Research Guidelines for the development of complex interventions, a theoretical model is applied in Paper 5. The final paper presents a qualitative study with UHR individuals, their parents and clinicians to explore barriers and facilitators to living a healthy lifestyle and inform the development of a physical health intervention. A final evidence synthesis includes recommendations for future work and the clinical implications of this thesis. The findings of this PhD provide an important and timely contribution to early intervention research. Prior to this work, the physical health of UHR individuals had been largely under researched. For the first time, this PhD presents evidence to suggest individuals at ultra-high risk for psychosis experience cardiovascular risk, and there is an opportunity to intervene to promote physical health. Although not all UHR individuals will develop psychosis, many will continue to experience difficulties with their mental health. Given that this group are also more likely to live an unhealthy lifestyle, it is important to take a holistic approach to treating those at imminent risk for psychosis, considering both mental and physical health.

This dissertation provides a brief introduction into scanning tunneling microscopy, and then Chapter III reports on the design and operation of a cryogenic ultra-high vacuum scanning tunneling microscope (STM) coupled to a closed-cycle cryostat (CCC). The STM is thermally linked to the CCC through helium exchange gas confined inside a volume enclosed by highly flexible rubber bellows. The STM is thus mechanically decoupled from the CCC, which results in a significant reduction of the mechanical noise transferred from the CCC to the STM. Noise analysis of the tunneling current shows current fluctuations up to 4% of the total current, which translates into tip-sample distance variations of up to 1.5 picometers. This noise level is sufficiently low for atomic-resolution imaging of a wide variety of surfaces. To demonstrate this, atomic-resolution images of Au(111) and NaCl(100)/Au(111) surfaces, as well as of carbon nanotubes deposited on Au(111), were obtained. Other performance characteristics such as thermal drift analysis and a cool-down analysis are reported. Scanning tunneling spectroscopy (STS) measurements based on the lock-in technique were also carried out and showed no detectable presence of noise from the CCC. These results demonstrate that the constructed CCC-coupled STM is a highly stable instrument capable of highly detailed spectroscopic investigations of materials and surfaces at the atomic-scale. A study of electron transport in single-walled carbon nanotubes (SWCNTs) was also conducted. In Chapter IV, STS is used to study the quantum-confined electronic states in SWCNTs deposited on the Au(111) surface. The STS spectra show the vibrational overtones which suggest rippling distortion and dimerization of carbon atoms on the SWCNT surface. This study experimentally connects the properties of well-defined localized electronic states to the properties of their associated vibronic states. In Chapter V, a study of PbS nanocrystals was conducted to study the effect of localized sub-bandgap states associated with surface imperfections. A correlation between their properties and the atomic-scale structure of chemical imperfections responsible for their appearance was established to understand the nature of such surface states. This dissertation includes both previously published/unpublished and co-authored material.

abstract: With increasing concerns of the intrinsic toxicity of lead (Pb) in electronics, a series of tin (Sn) based alloys involving silver (Ag) and copper (Cu) have been proposed as replacements for Pb-Sn solder and widely accepted by industry. However, they have a higher melting point and often exhibit poorer damage tolerance than Pb-Sn alloys. Recently, a new class of alloys with trace amount of rare-earth (RE) elements has been discovered and investigated. In previous work from Prof. Chawla's group, it has been shown that cerium (Ce)-based Pb-free solder are less prone to oxidation and Sn whiskering, and exhibit desirable attributes of microstructural refinement and enhanced ductility relative to lanthanum (La)-based Sn-3.9Ag-0.7Cu (SAC) alloy. Although the formation of RESn3 was believed to be directly responsible for the enhanced ductility in RE-containing SAC solder by allowing microscopic voids to nucleate throughout the solder volume, this cavitation-based mechanism needs to be validated experimentally and numerically. Additionally, since the previous study has exhibited the realistic feasibility of Ce-based SAC lead-free solder alloy as a replacement to conventional SAC alloys, in this study, the proposed objective focuses on the in in-depth understanding of mechanism of enhanced ductility in Ce-based SAC alloy and possible issues associated with integration of this new class of solder into electronic industry, including: (a) study of long-term thermal and mechanical stability on industrial metallization, (b) examine the role of solder volume and wetting behavior of the new solder, relative to Sn-3.9Ag-0.7Cu alloys, (c) conduct experiments of new solder alloys in the form of mechanical shock and electromigration. The research of this new class alloys will be conducted in industrially relevant conditions, and the results would serve as the first step toward integration of these new, next generation solders into the industry. / Dissertation/Thesis / Ph.D. Materials Science and Engineering 2012

abstract: For this project, the diffuse supernova neutrino background (DSNB) has been calculated based on the recent direct supernova rate measurements and neutrino spectrum from SN1987A. The estimated diffuse electron antineutrino flux is ∼ 0.10 – 0.59 /cm2/s at 99% confidence level, which is 5 times lower than the Super-Kamiokande 2012 upper limit of 3.0 /cm2/s, above energy threshold of 17.3 MeV. With a Megaton scale water detector, 40 events could be detected above the threshold per year. In addition, the detectability of neutrino bursts from direct black hole forming collapses (failed supernovae) at Megaton detectors is calculated. These neutrino bursts are energetic and with short time duration, ∼ 1s. They could be identified by the time coincidence of N ≥2 or N ≥3 events within 1s time window from nearby (4 – 5 Mpc) failed supernovae. The detection rate of these neutrino bursts could get up to one per decade. This is a realistic way to detect a failed supernova and gives a promising method for studying the physics of direct black hole formation mechanism. Finally, the absorption of ultra high energy (UHE) neutrinos by the cosmic neutrino background, with full inclusion of the effect of the thermal distribution of the background on the resonant annihilation channel, is discussed. Results are applied to serval models of UHE neutrino sources. Suppression effects are strong for sources that extend beyond z ∼ 10. This provides a fascinating probe of the physics of the relic neutrino background in the unexplored redshift interval z ∼ 10 – 100. Ultimately this research will examine the detectability of DSNB, neutrino bursts from failed supernovae and absorption effects in the neutrino spectrum. / Dissertation/Thesis / Ph.D. Physics 2013

Aplicações de aço de ultra-alta resistência, como aqueles aplicados em aeronaves, exigem materiais com uma combinação excepcional de propriedades mecânicas, dentre as quais, elevada resistência mecânica, tenacidade e resistência à fadiga. O VART 100 é um novo desenvolvimento da Indústria Villares Metals e apresenta-se como uma nova alternativa de aços de ultra-alta resistência atualmente no mercado internacional, sendo sua composição química diferenciada, devido a um maior teor de níquel, cromo, molibdênio, adição de cobalto e baixo teor de carbono. O presente trabalho tem como objetivo estudar a tenacidade ao impacto e a vida em fadiga (S-N) do aço VART 100 e compará-lo com valores obtidos na literatura para os aços de ultra-alta resistência tais como os aços SAE 300M e AerMet100. Para o atendimento deste objetivo, foram executadas análises metalográficas, ensaio de impacto conforme norma ASTM E23, ensaios de fadiga rotativa em controle de tensão para obtenção das curvas tensão versus vida, S-N, conforme especificado pela norma DIN 50113, análise das superfícies fraturas e microestruturas, observados em microscópios óticos, eletrônico de varredura e transmissão.Quanto a composição química do VART 100 observa-se que com excessão do \'AL\' este atendeu a especificação da norma SAE AMS6532 acarretando a formação de inclusões não metálicas de alumina. Com relação aos ensaios de impacto, a energia absorvida superou os resultados do aço 300M, mas ficou muito inferior ao Aermet100. Observou-se a presença de fratura intergranular em alguns CPS o que nos leva a suspeitar da presença de cementita nos contornos de grão. Quanto ao médio do limite de resistência a fadiga dos três aços, encontramos valores de 800, 850 e 936 MPa para o 300M, VART 100 e AerMet100, respectivamente. Analisando as superfícies fraturadas após ensaio de fadiga, identificamos e localizamos partículas de alumina na superfície, sub-superficie e internamente no material, com diâmetro variando entre 12,2 e 15,6 &#956m, que atuaram como núcleos para a formação de trincas por fadiga e possivelmente reduzindo a tenacidade ao impacto do VART 100. De forma geral o VART 100 apresenta boas propriedades mecânicas de resistência, de tenacidade e de limite de resistência a fadiga, os quais são superiores aos valores do 300M mas ainda inferior ao AerMet100. / Ultra high strength steel applications, such as those in aircrafts, require materials with an exceptional combination of mechanical properties, including high strength, toughness and fatigue resistance. The VART 100 is a new development of Villares Metals Industry and presents itself as a new alternative of steel with ultra-high strength currently on the international market, with its distinctive chemical composition, due to a higher content of nickel, chromium, molybdenum, adding cobalt and low carbon. The present work aims to study the impact toughness and life in fatigue (S-N) steel VART 100 and compare it with values from the literature for ultra high-strength steels such as steel and SAE 300M AerMet100. To meet this objective, metallographic analysis, impact test according to ASTM E23, rotative fatigue testing in tension control to obtain the stress versus life curves, S-N were performed as specified by DIN 50113, analysis of fracture surfaces and microstructures observed in optical microscopes, scanning electron and transmission.The results indicate that the VART steel exhibits excellent mechanical properties its upper than 300M steel, but some of those lower than AerMet100. The chemical composition of VART100 is observed that with the exception of \'AL\' is accord to specification SAE AMS6532 leading to formation of non-metallic inclusions of alumina. Regarding the impact tests, the absorbed energy is upper than results of the 300M steel, but was much lower than Aermet100. We observed the presence of intergranular fracture in some CPS which leads us to suspect the presence of cementite at grain boundaries. As for the average fatigue endurance limit of the three steels, the values found were 800, 850 and 936 MPa for the 300M, and VART 100 AerMet100 respectively. Analyzing the fractured surfaces after fatigue test, we identified and located alumina particles on the surface, sub-surface and inside the material, with diameters ranging between 12.2 and 15.6 µm, which acted as nuclei for the formation of cracks by fatigue and possibly reducing the impact toughness of the VART 100. Generally the VART 100 has good mechanical properties of strength, toughness and fatigue endurance limit, which values are greater than 300M but still lower than AerMet100.

Orientador: Pilar Rodriguez de Massaguer / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T11:41:03Z (GMT). No. of bitstreams: 1 Sanches_CristianaDePaulaPacheco_D.pdf: 39491118 bytes, checksum: 1b9b67b564e9684ca74114092ff37150 (MD5) Previous issue date: 2005 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Doutorado / Doutor em Ciência de Alimentos

Orientador: Vitor Baranauskas / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-11T10:03:42Z (GMT). No. of bitstreams: 1 Roos_Mathias_M.pdf: 4816472 bytes, checksum: 51a357faa29ccbd01723b1d6ca5abf27 (MD5) Previous issue date: 2007 / Resumo: Na primeira parte deste trabalho amostras de diamante poli-cristalino dopado com boro foram crescidas por deposição química a vapor assistida por filamento quente. As características de emissão de campo foram investigadas. A dopagem (NB) em amostras diferentes foi variada pelo controle da concentração B/C no fluxo de gases durante o processo de crescimento. Os campos limiares (Eth) para emissão de campo foram medidos e relacionados com as concentrações B/C usadas. Assim, a influência das bordas entre os grãos, a dopagem e a morfologia da superfície na emissão de campo foram investigadas. A saturação da dopagem foi observada para altas concentrações B/C. O transporte de cargas através das bordas entre os grãos e as propriedades locais de emissão na superfície foram modeladas por dois mecanismos que afetam a emissão de campo. Correntes de emissão de 500 nA·cm-2 foram obtidas para campos elétricos de 8 V·µm-1. Na segunda parte desta tese, a construção de um novo sistema de ultra alto vácuo (UHV) para realizar medições de emissão de campo é descrita. A construção inclui o projeto integral de uma câmara de UHV com sistema de bombas, conjunto de manipuladores, suportes mecânicos e a infraestrutura do laboratório / Abstract: In the first part of this thesis, the study of field emission properties of hot filament chemical vapor deposited boron doped polycrystalline diamond is described. The doping level (NB) of different samples was varied controlling the B/C concentration in the gas feed during the growth processes. The threshold field (Eth) for electron emission in dependence on different B/C concentrations was measured and the influence of grain boundaries, doping level and surface morphology on the field emission properties was investigated. For high B/C ratios doping saturation was observed. Carrier transport through conductive grains and local emission properties of surface sites figured out to be two independent limiting effects on field emission. Emitter currents of 500 nA·cm-2 were obtained using electric fields less than 8 V·µm-1. In the second part the construction of a new UHV system for field emission measurements is described, including the complete project of a UHV chamber with pump system, manipulators and sample transfer system, mechanical supports and the infrastructural requirements of the laboratory / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Nos últimos 30 anos o crescimento paralelo das Ciências de Superfície tradicionais, em ambiente de ultra-alto vácuo (UHV), com a Eletroquímica levou ao nascimento de um novo campo interdisciplinar: Física de Superfície e Eletroquímica. Técnicas de ambas as áreas dão informações complementares e assim, quando realizadas em conjunto podem fornecer muitas respostas em nível atômico, estrutural e eletrônico quando o eletrodo está em contato com a solução eletrolítica. A intenção primordial dessa Dissertação foi o estudo fundamental das fases ricas em oxigênio presentes na superfície de Ru(0001) através de caracterizações eletroquímicas e morfológicas utilizando um sistema que permitiu o acoplamento de uma célula eletroquímica miniatura de fluxo a câmaras de UHV. Inicialmente exibi-se a modificação e a construção de equipamentos necessários para a preparação do sistema binário Au-Pt(111) e do óxido monocristalino Ru2O(110). Imagens de STM em escala morfológica mostraram o crescimento anisotrópico do filme de RuO2(110) sobre um substrato monocristalino de Ru(0001). Resultados obtidos através da técnica de Voltametria Cíclica na eletrooxidação de CO em RuO2(110) corroboraram cálculos teóricos sobre a estrutura da superfície quando esta em ambiente úmido. Superfícies modelos baseadas em ouro, crescido epitaxialmente sobre um substrato de Pt(111), foram preparadas no sistema de UHV. Dados eletroquímicos foram correlacionados às composições superficiais destas, mostrando o efeito do substrato prevalecendo sobre o efeito eletrônico. / In the last 30 years the parallel growth of the traditional Surface Science, under UHV environment, and Electrochemistry gave rise to a new interdisciplinary field: Surface Science and Electrochemistry. Techniques from both sciences give complementary information. Thus, in tandem, they are able to elucidate many atomic, structural and electronic phenomena, of an electrode in contact with a solution. The main goal of this Dissertation was the fundamental study of the Oxygen-rich Ru(0001) surface through electrochemical and morphologic characterizations using a coupled system which allowed the attachment of a miniature flow cell to UVH-chambers. Initially it is shown the construction and modifications of required equipments for the preparation of the binary system Au-Pt(111) and single crystal RuO2(110) oxide. Attainable morphological STM images demonstrated the anisotropic growth of the RuO2(110) over a Ru(0001) substrate. Results of the electrooxidation of CO on RuO2(110), obtained by means of Cyclic Voltammetry, corroborated theoretical calculations concerning the oxide superficial structure in a humid environment. Model surfaces based on Au, epitaxialy grown on a Pt(111) substrate, were prepared under UHV conditions. Electrochemical data and superficial composition were correlated, confirming that the substrate effect overcomes electronic strain effects.

Spark plasma sintering (SPS), also known as direct current sintering (DCS) is an advanced sintering technique that and uses a continuous pulsed direct current to rapidly process materials through Joule heating and offers significant advantages and versatility over conventional sintering methods. The technique features in energy saving owing to high heating rates and is very suitable for consolidation as well as diffusion bonding of electrical conductive advanced ceramic materials such as ultra high temperature ceramics (UHTCs). However, cooling rate in SPS also plays an important role as it directly influences the generation of residual stress especially for specimens consist of dissimilar phases such as composites and laminates primarily due to CTE mismatch. Therefore, in order to produce high quality materials, a zirconium diboride with addition of silicon carbide (ZrB2-SiC) ultra high temperature ceramic composite is selected to investigate the effect of cooling rate in SPS on microstructure and mechanical properties. After being densified at the target temperature, ZrB2-25vol%SiC specimens are cooled from 1800°C using controlled cooling rates of 10 °C/minute to ~225.5 °C/minute (free cooling). A time dependent finite element analysis (FEA) model is used to simulate the temperature gradients across the specimens at dwell times and during the cooling processes. The residual stress within the specimens are experimentally verified using X-ray diffraction (XRD) and Raman spectrometry, and found maximum residual stress within the specimen cooled at 225.5 °C/minute. Peak Hardness and moderate elastic modulus is found for specimen sintered at 1800 °C and cooled at 100 °C/minute, which make this temperature and cooling rate appropriate conditions for future fabrication of UHTCs with similar thermal and electrical properties. These materials are of great interest for their excellent high-temperature capabilities, wear and corrosion resistance, and are regarded as material candidates for engineering applications in extreme environments. Therefore, development of an effective joining technique is important since near-net shape fabrication is challenging, and joints formed by brazing or conventional solid-state diffusion bonding limit the mechanical strength and high temperature applications of the base materials. Using SPS we have rapidly and successfully joined ZrB2 to hafnium diboride (HfB2) at 1750 and 1800 °C within a minute through electric current assisted solid-state diffusion bonding. The electric current enables localized Joule heating as well as plastic deformation of the mating surface asperities, and enhances the elemental interdiffusion process at the HfB2/ZrB2 interfaces owing to electromigration, which leads to the formation of ZrxHf1-xB2 solid solution. A series of characterization and analytical techniques including scanning electron microscopy (SEM), wavelength dispersive spectroscopy (WDS), electron backscatter diffraction (EBSD), and scanning transmission electron microscopy (S/TEM) are employed to study the microstructure and chemical composition at of the HfB2/ZrB2 interfaces. Apart from enhanced diffusion as a result of electromigration, the applied electric current can also be use to promote plastic deformation in ZrB2, which does not go through gross plastic deformation due to its extremely high melting point and brittle nature even when elevated temperature and pressure are applied. Through “electroplastic effect” (an effect based on electromigration) the mobility and multiplication of the existing dislocations in ZrB2 is enhanced, and a “metal-like” primary recrystallization phenomenon in the ZrB2 is observed meaning the material has experienced a sufficient amount of plastic deformation and reached the critical dislocation density and configuration for nucleation of “strain-free” grains. The average grain size of the recrystallized grain is only ½ of its original value. These findings suggest great potentials in microstructural tailoring and grain refinement of conductive advanced ceramics using SPS, and provide promising ideas for future fabrications and applications.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第17154号 / 工博第3644号 / 新制||工||1553(附属図書館) / 29893 / 京都大学大学院工学研究科建築学専攻 / (主査）教授 中島 正愛, 教授 吹田 啓一郎, 教授 金子 佳生 / 学位規則第4条第1項該当