abstract: This dissertation presents research findings on the three materials systems: lateral Si nanowires (SiNW), In₂Se₃/Bi₂Se₃ heterostructures and graphene. The first part of the thesis was focused on the growth and characterization of lateral SiNW. Lateral here refers to wires growing along the plane of substrate; vertical NW on the other hand grow out of the plane of substrate. It was found, using the Au-seeded vapor – liquid – solid technique, that epitaxial single-crystal SiNW can be grown laterally along Si(111) substrates that have been miscut toward [11− 2]. The ratio of lateral-to-vertical NW was found to increase as the miscut angle increased and as disilane pressure and substrate temperature decreased. Based on this observation, growth parameters were identified whereby all of the deposited Au seeds formed lateral NW. Furthermore, the nanofaceted substrate guided the growth via a mechanism that involved pinning of the trijunction at the liquid/solid interface of the growing nanowire. Next, the growth of selenide heterostructures was explored. Specifically, molecular beam epitaxy was utilized to grow In₂Se₃ and Bi₂Se₃ films on h-BN, highly oriented pyrolytic graphite and Si(111) substrates. Growth optimizations of In₂Se₃ and Bi₂Se₃ films were carried out by systematically varying the growth parameters. While the growth of these films was demonstrated on h-BN and HOPG surface, the majority of the effort was focused on growth on Si(111). Atomically flat terraces that extended laterally for several hundred nm, which were separated by single quintuple layer high steps characterized surface of the best In₂Se₃ films grown on Si(111). These In₂Se₃ films were suitable for subsequent high quality epitaxy of Bi₂Se₃ . The last part of this dissertation was focused on a recently initiated and ongoing study of graphene growth on liquid metal surfaces. The initial part of the study comprised a successful modification of an existing growth system to accommodate graphene synthesis and process development for reproducible graphene growth. Graphene was grown on Cu, Au and AuCu alloys at varioua conditions. Preliminary results showed triangular features on the liquid part of the Cu metal surface. For Au, and AuCu alloys, hexagonal features were noticed both on the solid and liquid parts. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2014

M. Ing. / This work describes the establishment of an intelligent control system on board an AGV for automatic adaptation to the motions and actions of industrial robots. The movements can represent an assembly sequence or material loading sequence. A relationship is established between the workspaces of the industrial robot and the AGV. The coordinate systems are integrated for the AGV to respond to the movements of the industrial robot in the correct way. The integration of these two different coordinate systems leads to the creation of a common workspace. Within this common workspace, the AGV interacts with the robot using the same reference points. The mathematical analysis and practical implementation of this transient workspace is described. The adaptive control presented allows for an intelligent decision making process to be performed on line with the use of an expert system.

The present paper is devoted to the investigation of the guided wave problem. This problem is formulated as the eigenvalue problem with a compact self-adjoint operator pencil. Applying the minimax principle for the compact operators in the Hilbert space we obtain a necessary and sufficient condition for the existence of a preassigned number of linearly independent guided modes. As a consequence of this result we also derive simple sufficient conditions, which can be easily applied in practice. We give a statement of the problem in a bounded domain and propose an efficient method for solving the problem.

Automated Guided Vehicles hav gained much attention in the industry especially with relevance to container handling at the seaports.

Near-infrared dyes can be used as theranostic agents in cancer management based on their optical imaging and localized hyperthermia capabilities. However, their clinical translatability is limited by issues such as photobleaching, short circulation times, and non-specific biodistribution. We studied the applications of IR820 in optical imaging and hyperthermia, and we prepared nanoconjugate formulations to overcome some of the aforementioned limitations. Free IR820 can be used for optical imaging, with a strong signal still present 24 hours after i.v. injection, an elimination plasma half-life in the order of hours, and primary biodistribution to liver, lung, and kidneys. After 808-mn laser exposure, IR820 can also raise in vitro temperatures to the 41-43°C range that can selectively inhibit cancer cell growth. We conjugated IR820 with PEG-diamine via ionic interactions to create nanoconjugates (IR820-PDNCs) with diameters of approximately 50-nm per SEM and a zeta potential of 2.0±0.9 mV. IR820-PDNCs enhanced cellular internalization compared to IR820 for imaging in SKOV-3, MES-SA, and Dx5 cancer cells. The nanoconjugates also significantly enhanced hyperthermia-mediated cytotoxicity in MES-SA and Dx5 compared to the free dye (p

Orientador: Enilson Antonio Sallum / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-26T23:34:09Z (GMT). No. of bitstreams: 1 Franca_IsabelaLima_M.pdf: 1330190 bytes, checksum: 6782efacdca31e69f907222817356c7c (MD5) Previous issue date: 2015 / Resumo: O objetivo deste estudo foi avaliar, clinicamente, a utilização do Retalho Semilunar Posicionado Coronariamente (RSPC) para tratamento de recessões gengivais, com ou sem associação à proteína derivada da matriz do esmalte (EMD). Foram selecionados 30 pacientes, que foram randomizados e alocados em dois grupos: teste (RSPC + EMD) e controle (RSPC sozinho). Para serem incluídos no estudo, os indivíduos deveriam apresentar recessões gengivais vestibulares localizadas classe I de Miller com altura maior ou igual a 2,0mm e menor que 4,0 mm, em caninos ou pré-molares superiores. Parâmetros clínicos avaliados: altura da recessão gengival (ARG), largura da recessão gengival (LRG), nível de inserção clínica (NIC), profundidade de sondagem (PS), altura de tecido queratinizado (ATQ), espessura de tecido queratinizado (ETQ) e altura (AP) e largura (LP) das papilas mesial e distal, além de índice de placa (IPL) e índice gengival (IG). Estes parâmetros foram medidos nos seguintes períodos: baseline, 90 dias e 180 dias após o procedimento cirúrgico. Nenhuma diferença estatisticamente significante foi observada entre os grupos em relação à redução da retração gengival com 6 meses de acompanhamento, embora tenha sido encontrada maior porcentagem de cobertura radicular no grupo RSPC+EMD (91%), quando comparado ao RSPC (87%) (p>0,05). Cobertura radicular completa foi obtida em 60% dos sítios no RSPC enquanto no grupo RSPC+EMD foi observada em 66,67% dos sítios. Dentro dos limites do presente estudo pôde-se concluir que o RSPC, associado ou não a EMD, levou a redução da recessão gengival, sem diferença estatística entre os grupos, após 6 meses de acompanhamento pós-operatório / Abstract: The aim of this study was to evaluate clinically the use of the Semilunar Coronally Positioned Flap (SCPF) for the treatment of gingival recessions, with or without Enamel Matrix Derivative (EMD). Thirty patients were selected, randomized and allocated in two groups: test (SCPF + EMD) and control (SCPF alone). To attend the study, subjects should present buccal Miller class I gingival recessions with height greater than or equal to 2.0 mm and less than to 4.0 mm in maxillary canines or premolars. Clinical parameters evaluated: gingival recession height (GRH), gingival recession width (GRW), clinical attachment level (CAL), probing depth (PD), height (HKT) and thickness (TKT) of keratinized tissue and papillas height (HP) and width (LP), as well as plaque and gingival index. These data were collected at baseline, 90 days and 180 days after surgery. No statistically significant difference was observed between the groups regarding the reduction of gingival recession after 6 months of follow-up, although a higher percentage of root coverage was found in SCPF + EMD group (91%), when compared to the SCPF (87%) (p> 0.05). Complete root coverage was observed in 60% of the sites of the control group (SCPF alone) and in 66,67% of the sites of the test group (SCPF+EMD). Within the limits of this study it was concluded that SCPF, associated or not with EMD may provide a reduction in gingival recession, with no statistical difference between groups / Mestrado / Periodontia / Mestra em Clínica Odontológica

Low levels of learner performance in Mathematics in the Senior Phase (Grades 7-9) in South Africa is often attributed to insufficient mathematics content knowledge among teachers. Although this view might be justifiable, it is often incorrect to assume that content knowledge alone will solve the problem of low performance in mathematics. This study, therefore, argues that understanding learner misconceptions and/or errors and their underlying intricacies could provide the basis for instructional decision making, subsequently improved performance in mathematics. The purpose of the study was to explore the implications of teachers’ understanding of learner errors for mathematics learning. The study was guided by qualitative methods using a case study design which involved data collection from two schools, followed by in-depth data analysis. Two theoretical lenses, namely, Cognitively Guided Instruction (CGI) and Constructivist theory were used to explore the main research question: What are the implications of the teachers’ understanding of learner errors on the learning of school mathematics in the Senior Phase (specifically Grade 9)? Data was collected through lesson observations, analysis of learners’ test responses and interviews. The findings revealed that teachers’ understanding of learner errors from written responses differed notably from intricacies of same errors emanating from interviewing the learners as well as the same errors analysed by the researcher. The implications of these findings suggest the likelihood of a mismatch between teachers’ instructional decision making and learner misconception/errors and this may hamper effective learning of mathematics. / Dissertation (MEd)--University of Pretoria, 2020. / Science, Mathematics and Technology Education / MEd / Unrestricted

As mental health is becoming increasingly prioritized, the disparity between the amount of undergraduate students who need mental health services and the amount of undergraduate students that actually receive this help is also becoming more noticeable. Over the past decade, there have been an increasing number of students seeking mental health services, with more students being diagnosed with mental health conditions. There have also been a rising number of students reporting heightened stress and anxiety due to COVID-19. With the increasing mental health diagnoses, especially during COVID-19, it is more important than ever to provide effective options for students to reduce their anxiety. To address this issue, we examined the effects of short easily accessible interventions including chair yoga, visual meditation and sound therapy to decrease anxiety in healthy college students. We report that a single session of five-minute chair yoga (p = 0.001) or visual meditation (p = 0.026) significantly reduced anxiety, as measured by the State-Trait Anxiety Inventory. We propose that results of this study be considered preliminary data in starting a self-help system for undergraduate students, especially during periods of exceptionally high stress, such as midterms or finals.

<p>Automated Guided Vehicles (AGV) are becoming an increasingly popular system for performing materials handling functions in industry today. The design and implementation of an Automated Guided Vehicle System (AGVS) is a complex issue and involves many aspects. It is highly advisable to design and plan the system prior to its implementation. This project considers some of the key issues and parameters in the initial design phase of an AGVS for a company manufacturing anti lock braking systems for automobiles. The design of the AGVS is carried out using simulation-animation techniques. PROMODEL pc, a popular manufacturing simulator is used for developing the simulation models. Different AGVS alternatives are considered. A multi-attribute framework is used for developing and analyzing the AGVS alternatives. The recommended AGVS design alternative is chosen based on economic justification and satisfaction of the company's throughput requirements. / Master of Engineering

see document / Master of Science