No description available.

Ultra-high performance concrete (UHPC) is a recently developed concrete gaining a lot of interest worldwide, and a lot research has been conducted to determine its material properties. UHPC is known for its very high strength and high durability. Association Francaise de Genie Civil (AFGC) has defined UHPC as a concrete exhibiting compressive strength greater than 150 MPa (22 ksi). To utilize the full compressive strength of UHPC, complementary tension reinforcement is required. A recent research study to find light weight yet high strength alternative deck systems for Florida movable bridges demonstrated that a composite UHPC and high strength steel (HSS) reinforcement deck system is a viable alternative. However, failure modes of the deck system observed during experimental testing were shear failures rather than flexural failures. Interestingly, the shear failures were ductile involving large deformations and large sectional rotations. The purpose of this research is to quantify the sensitivity of UHPC structural member mechanical response to different shear and normal stress demands, and investigate the underlying failure modes. An experimental investigation on small-scale prisms without reinforcement, prisms reinforced with ASTM Grade 60 steel, and prisms reinforced with high strength steel was carried out to capture load-deflection behavior as well as modes of failure of the UHPC specimens. Numerical analysis based on modified compression field theory (MCFT) was developed to verify experimental results at the section level, and further verification using continuum methods was performed using MCFT/DSFM (disturbed stress field method) based finite element analysis software (VecTor2). Results from the numerical analysis could reasonably predict the load-displacement as well as the failure modes of the experimental specimens. Obvious flexural failure was observed on unreinforced UHPC specimens where wide crack opening gradually widened at the bottom fiber of the concrete to the loading position. Whereas UHPC-Grade 60 steel specimens experienced ductile flexural failure with similar wide crack opening after the rebar yielded. On the other hand, UHPC-MMFX specimens largely failed in shear from a diagonal tension crack and crush of concrete top fiber.

No description available.

No description available.

The primary aim of this study was to ascertain whether teacher burnout is accompanied by physiological, psychological and behavioural symptoms. The Maslach Burnout Inventory was used to ascertain the levels of burnout among a sample of 282 Indian teachers of all ranks in ex - House of Delegates schools in the Kwazulu - Natal region. The Burnout Manifestations Scale was used to elicit those symptoms which burned out subjects exhibited the most. While 23 % of the sample appeared vulnerable to burnout, 7% appeared to be already burned out. It was found that with a few exceptions, the sample was susceptible to a lesser or greater degree to almost all of the symptoms listed in the Burnout Manifestations Scale. As no significant differences between the groups was detected in the selected demographic variables, it can be concluded that anyone, irrespective of their sex, marital status or any other variable, can become vulnerable to burnout. / Psychology of Education / M. Ed. (Psychology of Education)

[pt] A compreensão da estrutura e funcionalidades ecológicas inscritas na transformação da Mata Atlântica fluminense, compreendida por fragmentos florestais em meio à crescente urbanização, são de suma importância ao entendimento do conteúdo da paisagem via história ambiental e ecologia da paisagem. A complexidade ambiental característica da contemporaneidade geográfica instaura a coadunação de diversas abordagens tanto epistemológicas quanto metodológicas na apreensão da paisagem enquanto mosaico e resultante das multiescalares intervenções de seus elementos fundantes: estruturais e funcionais. Tais elementos encontram-se estabelecidos sob diferenciadas condições devido à orientação da encosta –vertentes soalheiras e Noruega - apresentam níveis de umidade, temperatura e precipitações diferenciadas em até 160 porcento. O estudo utiliza os parâmetros e métodos de análise ambientais como: fitossociologia, físico-química do solo, aporte, decomposição e retenção hídrica de serrapilheira na compreensão da resultante ecológica das distintas orientações e sítios topográficos. Para tanto a influência de tais variáveis na produtividade florestal foram analisadas utilizando-se 12 coletores de serrapilheira no sítio amostral da bacia do Camorim – sítio St. Agostinho, relancionando-os aos dados de pluviosidade da estação meteorológica do Riocentro (GEORIO). Foram realizadas coletas quinzenais para a produção e trimestrais para o estoque de serrapilheira durante um ano. A produção de serrapilheira na orientação NE (bacia do Camorim) foi de 10.733,80 kg.ha.ano-1 e superior em relação à orientação SW no mesmo período (Bacia do Caçambe), com 9.463,88 kg.ha.ano-1, sendo a fração folhas preponderante às demais. Os resultados sugerem a influência tanto dos usos pretéritos – legado dos carvoeiros, quilombolas e agricultores tradicionais – quanto das variáveis ecológicas – orientação de encosta, sítio topográfico, precipitação e a condição vegetacional da floresta atlântica, etc. Entretanto, os limites analíticos vão além da impossibilidade de generalizar e simplificar a paisagem. As imprecisões científicas – comuns aos diversos campos epistemológicos – inscrevem-se na abordagem co-evolutiva ao apontar os desafios da padronização e modelagem da paisagem. A transformação da Mata Atlântica mesmo que no recorte espacial (bacias do Camorim e Caçambe) adotado, não é passível de simplificação analítica e os resultados obtidos confirmam tais limitações. / [en] The comprehension of the ecological structure and functions wrote by transformation of Atlantic Rainforest, understood as forest fragments involved by rising urbanization, is of basic importance in the understanding of the landscape by Environmental History and Landscape Ecology. The characteristically environmental complexity of the contemporary Geography settles the approaches convergence both epistemological as methodological in the landscape understandings, so as a patch and as a resultant of the multiscalar actions of their foundations elements: structurals and functionals ones. These elements are found under different conditions due to slope aspect – with different humidity, temperature and rainfall almost as 160 percent in the north slope. The currently study uses some parameters and environmental analysis as: phytosociology, soil phical-chemestry and litterfall production, decomposition and hydrological retention capacity in the understanding of the ecological resultants of the different orientation and topographic sites – soalheira and noruega slope. To investigate the influence of these variables on the forest productivity the litter dynamics were analyzed employing 12 littertraps randomly distributed at the sample site in Camorim basin – St. Agostinho site, and investigating the relation between pluviosity regime using rainfall data from GEORIO Metereological Station of Riocentro. The samples were collected at each 15 days for litter production and at three months for litter stock during one year. The litter production at NE aspect (Camorim Basin) was 10.733,80 kg.ha.ano-1 and greater than that found at Caçambe Basin (SW) - 9.463,88 kg.ha.ano-1, with leaf fraction greater than the others. The results suggest that the past uses - environmental legacy of the use of the coal collectors, quilombolas and traditional agriculture – and the ecological variables – slope aspects, topographic sites, precipitation, and rainforest vegetal condition etc. Despite that, the analytical limits bypass the impossibilities of landscape simplification. The science inaccuracies – common to all epistemological science areas – are written on the coevolutive approache when shows the challenges of landscape standardization and modeling. The rainforest transformation, even in the case of a well known adopted area (Camorim and Caçambe basins), were not easy to an analytical simplification as was demonstrated by the observed results.

The primary aim of this study was to ascertain whether teacher burnout is accompanied by physiological, psychological and behavioural symptoms. The Maslach Burnout Inventory was used to ascertain the levels of burnout among a sample of 282 Indian teachers of all ranks in ex - House of Delegates schools in the Kwazulu - Natal region. The Burnout Manifestations Scale was used to elicit those symptoms which burned out subjects exhibited the most. While 23 % of the sample appeared vulnerable to burnout, 7% appeared to be already burned out. It was found that with a few exceptions, the sample was susceptible to a lesser or greater degree to almost all of the symptoms listed in the Burnout Manifestations Scale. As no significant differences between the groups was detected in the selected demographic variables, it can be concluded that anyone, irrespective of their sex, marital status or any other variable, can become vulnerable to burnout. / Psychology of Education / M. Ed. (Psychology of Education)

One main goal of this thesis is to show that for every K it is possible to find K consecutive natural numbers that cannot be written as sums of three nonnegative cubes. Since it is believed that approximately 10% of all natural numbers can be written in this way, this result indicates that the sums of three cubes distribute unevenly on the real line. These sums have been studied for almost a century, in relation with Waring's problem, but the existence of ``arbitrarily long gaps'' between them was not known. We will provide two proofs for this theorem. The first is relatively elementary and is based on the observation that the sums of three cubes have a positive bias towards being cubic residues modulo primes of the form p=1+3k. Thus, our first method to find consecutive non-sums of three cubes consists in searching them among the natural numbers that are non-cubic residues modulo ``many'' primes congruent to 1 modulo 3. Our second proof is more technical: it involves the computation of the Sato-Tate distribution of the underlying cubic Fermat variety {x^3+y^3+z^3=0}, via Jacobi sums of cubic characters and equidistribution theorems for Hecke L-functions of the Eisenstein quadratic number field Q(\sqrt{-3}). The advantage of the second approach is that it provides a nearly optimal quantitative estimate for the size of gaps: if N is large, there are >>\sqrt{log N}/(log log N)^4 consecutive non-sums of three cubes that are less than N. According to probabilistic models, an optimal estimate would be of the order of log N / log log N. In this thesis we also study other gap problems, e.g. between sums of four fourth powers, and we give an application to the arithmetic of cubic and biquadratic theta series. We also provide the following additional contributions to Number Theory and Combinatorics: a derivation of cubic identities from a parameterization of the pseudo-automorphisms of binary quadratic forms; a multiplicity estimate for multiprojective Chow forms, with applications to Transcendental Number Theory; a complete solution of a problem on planar graphs with everywhere positive combinatorial curvature.