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<p>Premature debonding of externally bonded FRP laminate from retrofitted reinforced concrete (RC) members can lead to inefficient use of FRP and can limit the level of strength increase that can be achieved. In this investigation, novel carbon FRP anchors were used in an attempt to delay the onset of premature debonding and to achieve superior strength. Nine double shear tests were performed on small scale concrete prisms to determine the most suitable epoxy for bonding the anchors to the laminate and the concrete. One type of epoxy increased the ultimate load of the prism retrofitted with two anchors at each end of the laminate 83.7% over the control specimens without anchors. The second phase of the investigation consisted of testing six large scale T-beams with a 4500 mm span, 400 mm height and 500 mm flange width under four point bending. Two beams were tested without FRP reinforcement as control beams, one beam was tested with FRP only epoxy bonded and the remaining three beams were tested with the FRP epoxy bonded and anchored. One of the beams with 30 anchors exhibited a 46% increase in the debonding load over the beam without anchors while the FRP laminate attained a maximum strain equal to 80% of its ultimate strain capacity, a 94% increase over the beam strengthened with only epoxy bonded FRP. The results demonstrate the anchoring system’s effectiveness and a feasible way to efficiently utilize the FRP laminate.</p>

Yes / This paper investigates how to facilitate users’ exploration through data graphs for knowledge expansion. Our work focuses on knowledge utility – increasing users’ domain knowledge while exploring a data graph. We introduce a novel exploration support mechanism underpinned by the subsumption theory of meaningful learning, which postulates that new knowledge is grasped by starting from familiar concepts in the graph which serve as knowledge anchors from where links to new knowledge are made. A core algorithmic component for operationalising the subsumption theory for meaningful learning to generate exploration paths for knowledge expansion is the automatic identification of knowledge anchors in a data graph (KADG). We present several metrics for identifying KADG which are evaluated against familiar concepts in human cognitive structures. A subsumption algorithm that utilises KADG for generating exploration paths for knowledge expansion is presented, and applied in the context of a Semantic data browser in a music domain. The resultant exploration paths are evaluated in a task-driven experimental user study compared to free data graph exploration. The findings show that exploration paths, based on subsumption and using knowledge anchors, lead to significantly higher increase in the users’ conceptual knowledge and better usability than free exploration of data graphs. The work opens a new avenue in semantic data exploration which investigates the link between learning and knowledge exploration. This extends the value of exploration and enables broader applications of data graphs in systems where the end users are not experts in the specific domain.

Due to close proximity of different civil engineering structures, the ultimate bearing capacity and failure pattern of adjoining footings/anchors are often influenced by their mutual interference. The present thesis is an attempt to examine the interference effects on the ultimate failure loads and the elastic settlements for a group of closely spaced strip footings and anchors. In this thesis, a new experimental setup has been proposed to examine the response of interfering strip footings and strip anchors subjected to vertical loads but without having any eccentricity. Through out the investigation, it has been assumed that the magnitudes of loads on all the footings/anchors at any stage of settlement remain exactly the same. Unlike the existing experimental works of the previous researchers reported in literature, in the proposed experimental setup, there is no need to use more than one footing/anchor. As a result a much smaller size of the tank, in which the soil sample needs to be prepared, is required. In the proposed setup, it has been attempted to satisfy the boundary conditions existing along the vertical planes of symmetry midway between any two adjoining footings/anchors. To satisfy the governing boundary conditions, along the planes of symmetry, the interface friction angle is kept as small as possible, with the employment of a very smooth high strength glass sheet, and the associated horizontal displacements are made equal to zero. For two interfering footings/anchors case, only single plane of symmetry on one side of the footing needs to be modeled. On the other hand, for an infinite number of multiple footings/anchors, two vertical planes of symmetry on both the sides of the footing need to be simulated in the experiments. The proposed experimental setup is noted to yield reasonably acceptable results both for the cases of interfering footings and interfering anchors. The magnitudes of ultimate failure loads for the interfering footings/anchors are expressed in terms of the variation of the efficiency factor ( ξγ) with respect to changes in the clear spacing(s) between the footings/anchors; wherein, an efficiency factor is defined as the ratio of the magnitude of the failure load for an intervening strip footing/anchor of a given width to that of an isolated strip footing/anchor having exactly the same width. From the experiments, the values of the efficiency factors are obtained for a group of two and an infinite number of multiple strip footings/anchors. The effect of two different widths of the footing/anchor on the magnitudes of the failure load is also studied. It is noted that for a group of two and infinite number of multiple footings, the magnitude of the ultimate failure load for an interfering footing becomes always greater than that for a single isolated footing. For the case of two footings, the value of ξγ becomes maximum corresponding to a certain critical s/B between two footings. At a given spacing, the value of ξγ is found to increase further with an increase in the value of φ. It is observed that, for a group of an infinite number of equally spaced multiple strip footings, the magnitude of ξγ increases continuously with a decrease in s/B; when the clear spacing between the footings approaches zero, the magnitude of ξγ tends to become infinity. The value of ξγ associated with a given s/B for the multiple footings case is found to become always greater than that for a two footing case. The effect of s/B on ξγ is found similar to that reported in theories in a qualitative sense. The value of ξγ at a given s/B associated for B = 4 cm both for two and multiple footings is found to become smaller as compared to that with B = 7 cm. In contrast to a group of interfering footings under compression, the magnitude of ξγ in the case of both two and multiple interfering anchors decreases continuously with a reduction in the value of s/B. For given values of s/B and embedment ratio ( λ = d/B ), the values of ξγ for the case of multiple anchors are found to be always lower than those for the case of two anchors; d = depth of the anchor. In comparison with the available theoretical values from the literature, the values of ξγ are found to be a little lower especially for smaller values of s/B. The comparison of the present experimental data with that reported from literature reveals that the interference of strip anchors will have relatively more reduction in the uplift resistance on account of interference as compared to a group of square and circular anchors; the present experimental data provides relatively lower values of ξγ as compared to the available experimental data (for square and circular footings). The value of s/B beyond which the response of anchors becomes that of an isolated anchor increases continuously with an increase in the value of λ. The magnitude of ξγ for given values of s/B and λ associated for B = 4 cm is found to become slightly greater as compared to that with B = 7 cm. Both for the cases of interfering footings and anchors, the ratio of the average ultimate pressure with the employment of the rough central plane (glass sheet glued with a sand paper) to that with the smooth central plane, is found to increase with (i) a decrease in the value of s/B, and (ii) an increase in the value of φ. The finite element analysis, based on a linear elastic soil-constitutive model, has also been performed for interfering footings and anchors to find the effect of interference on elastic settlements. The computations have revealed that for both the footings and anchors, a decrease in the spacing between the footings leads to a continuous increase in the magnitudes of the settlements. The increase in the settlement due to the interference becomes quite substantial for an infinite number of footings/anchors case as compared to two footings/anchors case. The effect of the Poisson’s ratio on the results is found to be practically insignificant.

The primary objective of the study was to explore the relationship between career anchors, job satisfaction and organisational commitment using a sample of 86 employees at four Information Technology companies in South Africa. A secondary objective was to determine whether individuals from various gender, race, position and age groups differed significantly regarding their career anchors, job satisfaction and organisational commitment. The instruments used were the Career Orientations Inventory (COI), Job Satisfaction Survey (JSS) and Organisational Commitment Questionnaire (OCQ). The research findings indicated that career anchors are partially related to participants’ job satisfaction and organisational commitment and participants’ levels of job satisfaction and organisational commitment are significantly related. The findings also showed that demographic groups differ significantly regarding their career anchors, job satisfaction and organisational commitment. It is recommended that interventions aimed at improving individual career decision making and organisational retention practices take cognisance of how these variables relate to individuals’ career anchors, job satisfaction and organisational commitment. The study is concluded with recommendations for Industrial and Organisational Psychology practices and further research.

Âncoras de glicosilfosfatidilinositol (GPI) são estruturas essenciais para a ancoragem de glicoconjugados e proteínas na superfície celular de protozoários. Trypanosoma cruzi produz uma gama de estruturas únicas de GPI, as quais ancoram mucinas e trans-sialidases, que participam de processos envolvidos na interação entre parasita e hospedeiro. Afim de estudar a biossíntese de âncora de GPI de T. cruzi e possivelmente utilizá-la como um potencial alvo anti-T.cruzi, este trabalho visa sintetizar análogos de âncoras de GPI e analisar o potencial destas moléculas como substratos da via biossintética de GPIs. Neste contexto, um pseudo-dissacarídeo 31 foi sintetizado através de O-glicosilação entre os doadores derivados de azido-glicopiranosídeo (32 ou 33a-d) e o acceptor de mio-inositol (34), preparados a partir de cloridrato de glucosamina (35) e metil-?-D-glucopiranósido (36), respectivamente, usando proteção/desproteção ortogonais. Cinco diferentes dadores de glicosídicos (32 e 33a-d) foram preparados para investigar a influcia dos seus grupos protetores na estereoselectividade da reações de O-glicosilação na presença de diferentes solventes para estudar o favorecimento da configuração ?, presente em GPIs. Ademais, a síntese do aceptor de mio-inositol 34 foi realizada em 12 etapas pela estratégia do rearranjo Ferrier para formar um derivado de ciclitol, além de diversas proteções/desproteções, funcionalizado que permite a introdução regiosselectiva da unidade de azido glicose (32-33a-d) e uma porção de fosfolípido no seu C-1 e posições C-6, respectivamente. Assim, O-glicosilação entre doador 33c e o acceptor 34, foi realizada utilizando TMSOTf como promotor para originar o composto 31c com boa estereoseletividade para ?, com elevado rendimento (~70%). Após a dealilação de 31c, a porção fosfodiéster contendo uma cadeia C-8 (87), preparada pela abordagem do H-fosfonato, foi anexada ao pseudo-dissacarídeo para gerar, após desprotecção global, o composto alvo 30a. A mesma estratégia sintética foi aplicada ao preparo do composto 91 contendo uma cadeia lateral alquil-naftil (90) que está em últmas etapas de desproteção para gerar o composto final 30c. Atualmente, o composto 30a está sendo testado como substrato da biossíntese de âncoras de GPI em membranas microssomais de Euglena gracilis, uma alga unicelular não patogênica, que pode potencialmente ser utilizada como modelo para parasitas humanos filogeneticamente relacionados. Após a incubação do potencial substrato de GPI 30a com membranas microssomais de E. gracilis para geração de metabólitos, será realizada análise do extrato por LC-MS e, eventualmente, isolamento dos produtos formados para posterior caracterização. Os produtos que apresentarem atividade como substrato ou como inibidores da biossíntese de GPI em E. gracilis serão também ensaiados na membrana microsomal do T. cruzi. / Glycosylphosphatidylinositol (GPI) anchors are essential molecules to attach glycoconjugates and proteins in protozoan\'s cell surface. Trypanosoma cruzi produces a range of unique GPI structures that anchor mucins and trans-sialidases which participate in important processes involved in the interaction between parasite and host. As an effort to study T. cruzi GPI anchor biosynthesis and possibly use it as a potential target for an antichagasic drug, this work aims to synthesize GPI anchor analogs (labelled or not) and analyze the potential of these molecules as substrates in the GPI biosynthetic pathway. In this context, a pseudo-disaccharide 31 was synthesized by O-glycosylation reaction between azide glycosyl donors (32 or 33a-d) and myo-inositol acceptor (34), prepared from glucosamine (35) hydrochloride and methyl ?-D-glucopyranoside (36), respectively, using orthogonal protection/ deprotection. Five different glycosyl donors (32 and 33a-d) were prepared to investigate the influence of their protective groups on the stereoselectivity of the O-glycosylation reaction in the presence of different solvents to afford the required GPI ?-linkage. In addition, the synthesis of the myo-inositol acceptor 34 was achieved using several protection/deprotection steps, besides the Ferrier rearrangement, to form a functionalized cyclitol derivative that enables the regioselective introduction of the azide glycoside unit and phospholipid moiety on its C-1 and C-6 positions, respectively. Then, O-glycosylation of acceptor 34 with donor 33c was accomplished in diethyl ether, using TMSOTf as promoter to give exclusively ?-anomer 31c in high yield. After deallylation of 31c, the phosphodiester moiety bearing an octyl chain (87), prepared by the H-phosphonate approach, was appended to the pseudo-disaccharide to yield, after deprotection, target compounds 30a. The same synthetic strategy was applied to the preparation of 30c, even though in the protective form, compound 91 bearing an alkyl-naphthyl side chain (90). Currently, compound 30a is being tested as substrates of GPI anchor biosynthesis in Euglena gracilis cell membranes, a non-pathogenic unicellular algae, which may potentially be used as a model for phylogenetically related human parasites. After incubation of the potential GPI substrate 30a with E. gracilis microsomal membranes for generation of metabolites, the analysis by LC-MS and, eventually, isolation of the products will be performed for further characterization. Products that show any substrate or inhibitory activities will be also assayed in T. cruzi microsomal membrane.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-26T09:23:06Z No. of bitstreams: 2 Dissertação - Emilly Dias da Silva - 2016.pdf: 6131512 bytes, checksum: 2ebac9ad8e2116f4ee2c3159379816ca (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-26T09:23:41Z (GMT) No. of bitstreams: 2 Dissertação - Emilly Dias da Silva - 2016.pdf: 6131512 bytes, checksum: 2ebac9ad8e2116f4ee2c3159379816ca (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-01-26T09:23:41Z (GMT). No. of bitstreams: 2 Dissertação - Emilly Dias da Silva - 2016.pdf: 6131512 bytes, checksum: 2ebac9ad8e2116f4ee2c3159379816ca (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-01-29 / The use of soil nailing technique can be an important alternative for the stabilization of a slope or an excavation. Nails are retaining elements that reinforce soil masses acting passively, requiring strains to mobilize their resistance. The mechanical behavior analysis of a structure with soil nailing technique can be made using limit equilibrium methods, being represented by loads applied to reinforcing layers or sub-horizontal slices of a slope. The slice has its base crossed by a reinforcing action line and the reinforcing nail is treated as a concentrated point load acting on the base point of intersection of a slice with the line of action. Thus, through analytical and numerical calculations, this dissertation studied the design of soil nailing structure considering variations of suction, which influences the soil resistance, simulating suction profiles of a typical soil of the Brazilian Midwest region. This study was conducted determining strength parameters on nail-soil interface by tests in the field, i.e. nail pullout tests, and soil strength and hydromechanical parameters determined in the laboratory. For this, two separate suction sections were studied, and in each case, numerically analyzed in soil nailing structures, obtaining the dimensions of the structure through a pre-sizing phase, and then analyzing the factor of safety of the structure using computer programming considering the Bishop method. In the first case, the distribution of suction was numerically simulated for the soil profile studied in a critical condition of rainfall in Goiania region. Then, the suction field profile was obtained for comparison with the first case. With the results of this research, it was possible to understand the increasement of resistance and safety fator of the structure when considering the suction effects at the design of soil nailed structures in a typical soil of Goiânia region. / A utilização de contenções em solo grampeado pode ser uma importante alternativa para a estabilização de um talude ou de uma escavação. Os grampos ou tirantes passivos são elementos de contenção ou de reforço de massas de solo que agem passivamente, requerendo deformações para mobilizar sua resistência. A análise do comportamento mecânico de uma estrutura onde existe solo grampeado pode ser feita através de métodos de equilíbrio limite, sendo representada por cargas de reforço aplicadas a camadas ou fatias sub-horizontais de um talude. A fatia tem a sua base atravessada por uma linha de ação de reforço e a carga de reforço é tratada como uma carga pontual concentrada agindo no ponto de intersecção da base de uma fatia com a linha de ação. Assim, através de cálculos por ferramentas analíticas e numéricas, o presente trabalho estudou o dimensionamento da estrutura de solo grampeado considerando a variação de sucção, que influencia a resistência do solo, simulando perfis de sucção de um solo típico da região do centro oeste brasileiro. Esse estudo foi realizado determinando parâmetros de resistência na interface grampo-solo por ensaios realizados em campo, como ensaios de arrancamento de grampo, e parâmetros de resistência e hidromecânicos do solo não saturado determinados em laboratório. Para isso, foram estudados dois perfis de sucção distintos e, para cada caso, analisou-se numericamente a estrutura de contenção em solo grampeado, obtendo-se as dimensões da estrutura através de um pré-dimensionamento, e, a seguir, analisando o fator de segurança da contenção utilizando programação computacional considerando o método de Bishop. No primeiro caso foi simulada numericamente a distribuição do perfil de sucção do solo estudado para uma condição de precipitação crítica na região de Goiânia. No segundo, foi obtido o perfil de sucção de campo para comparação com o primeiro caso. Com os resultados desta pesquisa, foi possível compreender o aumento da resistência e do fator de segurança da contenção ao considerar os efeitos de sucção no dimensionamento de uma estrutura de contenção em solo grampeado típico da região de Goiânia.

A presente dissertação versa sobre a determinação do parâmetro de adesão entre nata de cimento e rocha. Este parâmetro é de fundamental importância no dimensionamento de grampos e tirantes ancorados, sistemas de contenção frequentemente executados que utilizam da técnica de ancoragem. Ensaios de arrancamento in loco são comumente realizados para avaliar essa tensão de aderência, no entanto, muitas vezes, apenas se tornam viáveis financeiramente durante a etapa de execução das obras. A metodologia Composite Cylinder Bond Test (CCBT) permite a determinação da adesão de maneira mais simples e com menor custo, por meio de ensaios de laboratório utilizando corpos de prova mistos de rocha e nata de cimento, sendo, por isto, uma interessante alternativa para a etapa de definição paramétrica de projetos. Neste contexto, foram estudadas três litologias sedimentares do município de Caçapava do Sul/RS – aqui chamadas de conglomerado, arenito muito fino e arenito médio – pertencentes à Formação Varzinha. A caracterização dessas litologias foi realizada por meio de lâminas delgadas e outros ensaios de caracterização de laboratório A classificação textural do conglomerado é de conglomerado arenoso, o arenito muito fino é classificado como arenito lamoso e o arenito médio é classificado como arenito. Do ponto de vista composicional, o arenito muito fino é classificado como arcóseo, enquanto o arenito médio é classificado como arcóseo lítico. Noventa ensaios CCBT, além de ensaios de resistência à compressão simples das rochas e da nata de cimento foram realizados. As tensões de adesão médias obtidas dos ensaios de laboratório foram de 2,52 MPa para o conglomerado, 1,84 MPa para o arenito muito fino e 1,43 MPa para o arenito médio. Foi realizada uma avaliação de intervalos de confiança de valores de tensão de adesão, conforme a distribuição t-student. Concluiu-se que não apenas a resistência das rochas influencia nessa capacidade de adesão, mas também a capacidade de absorção d’água e a porosidade. Maiores valores dessas duas propriedades na rocha favorecem a adesão entre os dois materiais. Os valores encontrados em laboratório são compatíveis com dados de literatura de campo em rochas similares. / This dissertation evaluates the determination of the adhesion parameter between cement grout and rock. This parameter is of great importance on design of two systems frequently executed that use the technique of anchoring: rock anchors and bolts. Pull out field tests are commonly carried out to evaluate this bond strength, however, they are normally only economically feasible during the construction stage. The Composite Cylinder Bond Test (CCBT) methodology allows the adhesion determination in a simpler and cheaper way, by laboratory tests using mixed samples of rock and cement grout. Therefore, the CCBT is an interesting alternative to project definition of adhesion values. In this context, three different sedimentary lithologies from Caçapava do Sul/RS, Southern Brazil, were studied. The lithologies – called here as conglomerate, fine sandstone and medium sandstone – belong to Varzinha Formation. The characterization of these lithologies were made by thin sections and characterization laboratory tests The textural classification of the conglomerate was sandy conglomerate, the fine sandstone was classified as muddy sandstone, and the medium sandstone was classified as sandstone. In the view of their composition, the fine sandstone was classified as arkose, while the medium sandstone was classified as lithic arkose. Ninety CCBT tests, besides unconfined compression tests on rock and cement grout specimens were carried out. The average adhesion values obtained from laboratory tests were 2,52 MPa for the conglomerate, 1,84 MPa for the fine sandstone and 1,43 MPa for the medium sandstone. An evaluation of confidence intervals of adhesion was also carried out, according to t-student distribution. It was concluded that the adhesion strength was influenced not only by the unconfined compressive strength of the rocks, but also by their water absorption and porosity. Larger values of these two properties increased the adhesion between the two materials. The values obtained from laboratory tests are compatible with literature field data in similar rocks.