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Abstract The primary objective of this work is to study and model the fracture process and durability of paperboard cores in cyclic loading. The results are utilized in creating analytic model to estimate the life time of cores in printing industry. The life time means here the maximum number of winding-unwinding cycles before the core delaminates. This study serves also as an example of use of board as a constructional engineering material. Board is an example of complicated, fibrous, porous, hydroscopic, time dependent and statistic material. Different core board grades are typically made of recycled fibers. The material model in this work is linear-elastic, homogeneous and orthotropic. The material characteristics, elastic and strength properties are studied first. Then the material is studied from the points of view of fracture and fatigue mechanics. Some of the analysis and test methods are originally developed for fiber composites but have been applied successfully here also for laminated board specimen. An interesting finding is that Scott Bond correlates well with the sum of mode I and mode II critical strain energy release rates. It was also possible to apply Paris' law and Miner's cumulative damage theory in the studied example situations. The creation of the life time model starts by FEM-analysis of cracked and non cracked cores in a typical loading situation. The elastic-linear material model is used here. The calculated stresses are utilized in analytic J-integral model. The agreement between analytic and numerical J-integral estimations is good. The analytic life time model utilizes the analytic J-integral model, Miner's cumulative damage theory and analytically formulated Wöhler-curves which were constructed by applying the Paris' law. The Wöhler-curves were constructed also by testing cores to validate the theoretical results. The testing conditions are validated by FEM-analysis. The cores heat up when tested or used with non expanding chucks and a temperature correction was needed in the life time model to consider this. Also, single or multi crack model was used depending on the studied case. The calculated and tested durability prediction curves show good correspondence. The results are finally reduced to correspond to certain confidence level.

k-core is a notion capturing the cohesiveness of a subgraph in a social network graph. Most of the current research work only consider pure network graphs and neglect an important property of the nodes: influence. Li, Qin, Yu, and Mao introduced a novel community model called k-influential community which is based on the concept of k-core enhanced with node influence values. In this model, we are interested not only in subgraphs that are well-connected but also have a high lower-bound on their influence. More precisely, we are interested in finding top r (with respect to influence), k-core communities. We present novel approaches that provide an impressive scalability in solving the problem for graphs of billions of edges using only a consumer-grade machine. / Graduate

The existence of a thermotropic biaxial nematic liquid crystal phase has been a topic of great interest for almost half a century. Of the various mesogenic shapes suggested as being able to form this phase, theory has suggested that the V-shaped or "bent-core" molecule is one of the most promising candidates. In this thesis we use a simple mesogenic model of a bent-core molecule, constructed from a number of repulsive Weeks-Chandler-Andersen potentials that are assembled into a rigid V shape. Using this model we explore the spontaneous phase behaviour that occurs in a wide array of different systems of mesogens, using molecular dynamics simulations and isotropic initial conditions. We study the relationship between molecular bend angle and phase behavior for molecules constructed from 11 potentials. We find that the phase behaviour splits into two regions, above and below a critical bend angle. Molecules wider than this angle exhibit isotropic, uniaxial nematic and smectic A phases. Narrower molecules show no uniaxially aligned phases, and instead have a clustered phase with short-range ordering and no global alignment director. Increasing system size improves the smectic layering in the wider molecules, but does not affect the global alignment of the narrower molecules. Our model is extended to include the effect of the arm length of the molecule by changing the number of potentials from which the mesogens are constructed. As the molecule is reduced in size, the critical bend angle is seen to move slowly towards more linear molecules, reducing the size of the parameter space in which uniaxial nematic alignment is possible. At 5 beads, all mesophases are seen to disappear and systems remain isotropic. We also study the behaviour of binary mixtures of bent-core molecules, both of differing arm lengths and of differing bend angles. For arm length mixtures, molecules are seen to remain mixed in the isotropic and nematic phases, and phase separate on transition to a smectic phase. In addition, uniaxial nematic phases are induced in systems that have no nematic phase of their own in isolation. For mixtures of different bend angles, systems remain fully mixed in the smectic phases for differences of up to 10 degrees, and beyond this the two components begin to separate at the nematic–smectic transition.

The University of Pretoria is an international institution that has seen many of its alumni carry its good reputation and high standards into the global community. A well rounded student is one who has not only achieved academically, but also has learnt life skills through exposure to different people from all walks of life. The Core Student Centre is the heart of the University's campus that belongs to the students. It is a place where students will feel like they belong, and be unconsciouslyb encouraged to interact with fellow students. Branding in architecture is the vehicle through which centralised management,student ownership and consistency in high standards of service will keep the Core Student Centre as the hub of student activity on the University's campuses. The main campus in Hatfield is the pilot project, then the rest of the University's campuses will have their student centres adapted to have the Core brand be a campus-wide initiative. The students will then know to expect nothing but high quality standards associated with the brand. Copyright 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Bhebhe, T 2008, Rejuvenation of the campus core, MInt(Prof) dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-11272008-154959 / > C169/eo / Dissertation (MInt(Prof))--University of Pretoria, 2009. / Architecture / unrestricted

Made available in DSpace on 2014-06-12T23:04:14Z (GMT). No. of bitstreams: 2 arquivo8851_1.pdf: 4717828 bytes, checksum: 592acd5b2b91d1cead758a1666f091db (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007 / As indicações clínicas da core biopsy obedece aos mesmos critérios utilizados para biópsia cirúrgica, mas não há consenso na literatura quanto a sua indicação para avaliação das lesões na categoria mamográfica BI-RADS® 5 (ACR/Breast Imaging Reporting and Data System). Objetivo: Determinar a associação entre as alterações mamográficas e o diagnóstico histopatológico de material obtido por core biopsy estereotáxica de lesões mamárias impalpáveis classificadas na categoria mamográfica BI-RADS® 5, estabelecendo o valor preditivo positivo da mamografia nas lesões altamente suspeitas de malignidade. Materiais e métodos: Por meio de estudo retrospectivo, transversal, analítico, de comparação entre métodos diagnósticos, foram analisadas 70 core biopsies de lesões mamárias impalpáveis, classificadas radiologicamente como altamente suspeitas de malignidade (BI-RADS® 5), de 70 pacientes, atendidas em serviços privados de Anatomia Patológica e Radiologia da cidade do Recife, Pernambuco, no período de 2001 a 2006. Resultados: Eram do sexo feminino 68 (97,1%) pacientes e 2 (2,9%), do masculino. A idade variou de 17 a 87 anos, com média de 58 ± 15 anos. A mama esquerda foi acometida em 42 (60%) casos e a direita, em 28 (40%). Predominaram localização das lesões no QSE (44 casos; 62,9%) e nódulos irregulares espiculados (49 casos; 70%), 11 (15,7%) dos quais associados a microcalcificações. As microcalcificações estavam presentes em 31(44,3%) casos; sendo 16 (22,9%) casos não associados a nódulos, distorção arquitetural ou densidade assimétrica. As core biopsies foram constituídas por 3 a 16 fragmentos (média: 6±2). Não houve diferença na distribuição de freqüência de número de fragmentos em função dos diagnósticos histopatológicos (p>0,05) ou radiológicos (p=0,63). Houve diagnóstico de: 59 (84,3%) casos de carcinoma, 7 (10%) casos de lesões benignas e 4 (5,7%) com lesão borderline. O carcinoma invasivo foi o mais freqüente (49 casos; 70%) e em 15 (21,4%) casos associou-se a componente in situ. O carcinoma in situ puro correspondeu a 10 (14,3%) casos. Houve associação significante entre nódulos irregulares espiculados e carcinoma invasivo (41 casos; 58,6%; p=0,005). O tipo histológico mais encontrado foi o carcinoma ductal invasivo (34 casos; 69,4%). Dentre os carcinomas invasivos, 36 (73,5%) casos tiveram grau histológico 2, com predomínio da soma dos escores igual a 6 (34 casos; 69,4%). O CDIS padrão comedônico puro associou-se mais freqüentemente às microcalcificações. O valor preditivo positivo da avaliação mamográfica na categoria BI-RADS® 5 foi de 84,3%. O maior valor preditivo positivo foi verificado em nódulo irregular espiculado com microcalcificações, com ou sem, sem microcalcificações e microcalcificações sem nódulo (100%, 87,8%, 84,2% e 75%, respectivamente). Conclusões: A avaliação mamográfica das lesões impalpáveis enquadradas como altamente suspeitas de malignidade foi de alto valor preditivo para o diagnóstico de câncer, a maioria correspondendo a carcinoma invasivo. Os nódulos irregulares espiculados tiveram um alto valor preditivo para o diagnóstico de carcinoma, particularmente, quando associados às microcalcificações

This diploma thesis deals with creation of reduction core problem mainly in fired roofing tiles. With those is the emphasis on the impermeability and frost resistance. Black reduction core is reducing frost resistance but depends on firing temperature. At 1060 °C the reduction in frost resistance is not as unfavorable as at 900 °C. This thesis includes overview of research conducted on reduction core topic. There is enough literature focusing on frost resistance, experimental part is focused mainly on the impact of reduction core on impermeability and compares two types of production mixtures used in Czech Republic (calcium-containing type from Hranice and non-calcium type from Stod). It includes comparison of mixtures with fluidized fly ash and dust from grinding masonry elements. It opens discussion if those mixtures can be used for reduction core elimination.

Thesis advisor: Udayan Mohanty / The high surface area and atomic-level tunability offered by nanoparticles has defined their promise as heterogeneous catalysts. While initial studies began with nanoparticles of a single metal assuming thermodynamic shapes, modern work has focused on using nanoparticle composition and geometry to optimize nanocatalysts for a wide variety of reactions. Further optimization of these refined nanocatalysts remains difficult, however, as the factors that determine catalytic activity are intertwined and a fundamental understanding of each remains elusive. In this work, precise synthetic methods are used to tune a number of factors, including composition, strain, metal-to-metal charge transfer, atomic order, and surface faceting, and understand their impact on catalysis. The first chapter focuses on current achievements and challenges in the synthesis of intermetallic nanocatalysts, which offer long-range order that allows for total control of surface structure. A particular focus is given to the impact of the synthetic approach on the activity of the resulting nanoparticles. In the second chapter, multilayered Pd-(Ni-Pt)x nanoparticles serve as a controlled arena for the study of metallic mixing and order formation on the nanoscale. The third chapter controls the shell thickness of Au@PdPt core-alloyed shell nanoparticles on a nanometer scale to isolate strain at the nanoparticle surface. In the fourth chapter, the synthetic approaches of chapters two and three are applied to catalysis. In totality, the work presented here represents a brick in the foundation of understanding and exploiting structure-function relationships on the nanoscale, with an eye toward the rational design of tailored nanocatalysts. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.