Análise numérica de escorregamento em encostas

O perfeito entendimento de deslizamentos de terra tem sido objeto de grande interesse na engenharia geotécnica há muitos anos. Encostas naturais representam um desafio constante para os engenheiros, mais do que os taludes artificiais. Não é incomum que os escorregamentos causam perdas de vidas humanas e também danos materiais. As informações obtidas a partir de retro-análise de casos históricos, têm servido como uma ferramenta valiosa para a compreensão da estabilidade de taludes. Vale a pena notar que o primeiro método de cálculo de estabilidade de taludes, usando divisão de fatia, foi desenvolvido após um acidente na Noruega. Métodos de estabilidade por Equilíbrio Limite, desenvolvidos no século passado são atualmente utilizados na prática da engenharia. Apesar de suas deficiências, eles provaram ser confiáveis na determinação do Fator de Segurança. A geometria 2D e a abordagem completa da condição saturada são provavelmente as questões mais relevantes dos métodos atuais. A condição do solo não saturado está geralmente presente em taludes naturais e os métodos ignoram a influência da sucção do solo sobre a estabilidade do talude. O desenvolvimento de computadores no meio do século passado, tornaram os cálculos Equilíbrio Limite fáceis de serem executados. Por outro lado, eles não podem explicar a natureza do problema ou prever o comportamento do solo antes da ruptura. A década de 1960 marcou o início do desenvolvimento de programas de computador baseados em métodos numéricos que, entre outros, destaca-se, em geotecnia, a aplicação dos métodos de Elementos Finitos (FEM). Este método é ideal para muitos fins, uma vez que permite a simulação da sequência de construção e também a incorporação de diferentes modelos constitutivos. Este trabalho mostra a influência da sucção sobre a estabilidade de encostas naturais. Uma retroanálise de um escorregamento no Morro dos Cabritos, no Rio de Janeiro, foi feita através de um programa de análise de tensão (Plaxis 2D). Os resultados foram comparados com o FS obtido por programa de Equilíbrio Limite (Slide v5). O efeito de sucção do solo foi incorporada nas análises, através de sua influência sobre os parâmetros de resistência do solo e por diferentes possibilidades de infiltração de água na encosta. Este caso histórico foi estudado anteriormente por Gerscovich (1994), que na época, fez analise de fluxo e estabilidade utilizando um abordagem de Equilíbrio Limite 3D. Os resultados mostraram boa concordância entre a análise de Elementos Finitos e a simulação de Equilíbrio Limite, sem a presença de nível de água. Os resultados confirmaram que foi necessário haver pressões positivas para explicar a ruptura do talude.

Colonização natural por espécies nativas e exóticas das encostas degradadas da Serra do Mar

Os deslizamentos são eventos inerentes à dinâmica da Serra do Mar, nos trechos mais declivosos. Contudo, devido a alguns fatores de intervenção, como a poluição atmosférica, ocupação da base dos morros e outros, a incidência desses eventos tem aumentado. Diante disso, este estudo objetivou avaliar a dinâmica de colonização de áreas de encosta degradadas, como forma de subsidiar ações de recuperação. Para tanto, foram adotadas duas áreas experimentais, localizadas em trechos da serra do Mar próximos à Baixada Santista, onde foram lançadas parcelas de 1 m² e obtidos dados fitossociológicos. em seguida, as áreas foram limpas e os mesmos parâmetros da avaliação inicial, registrados, mensalmente, ao longo de um ano. Foram encontradas 20 espécies, pertencentes a 14 famílias botânicas, em sua maioria espécies exóticas ou nativas não regionais.

Particle and gaseous emissions from compressed natural gas and ultralow sulphur diesel-fuelled buses at four steady engine loads

Exhaust emissions from thirteen compressed natural gas (CNG) and nine ultralow sulphur diesel in-service transport buses were monitored on a chassis dynamometer. Measurements were carried out at idle and at three steady engine loads of 25%, 50% and 100% of maximum power at a fixed speed of 60 kmph. Emission factors were estimated for particle mass and number, carbon dioxide and oxides of nitrogen for two types of CNG buses (Scania and MAN, compatible with Euro 2 and 3 emission standards, respectively) and two types of diesel buses (Volvo Pre-Euro/Euro1 and Mercedez OC500 Euro3). All emission factors increased with load. The median particle mass emission factor for the CNG buses was less than 1% of that from the diesel buses at all loads. However, the particle number emission factors did not show a statistically significant difference between buses operating on the two types of fuel. In this paper, for the very first time, particle number emission factors are presented at four steady state engine loads for CNG buses. Median values ranged from the order of 1012 particles min-1 at idle to 1015 particles km-1 at full power. Most of the particles observed in the CNG emissions were in the nanoparticle size range and likely to be composed of volatile organic compounds The CO2 emission factors were about 20% to 30% greater for the diesel buses over the CNG buses, while the oxides of nitrogen emission factors did not show any difference due to the large variation between buses.

A natural model for architecture : the nature of the evolutionary model 1995

John Frazer's architectural work is inspired by living and generative processes. Both evolutionary and revolutionary, it explores informatin ecologies and the dynamics of the spaces between objects. Fuelled by an interest in the cybernetic work of Gordon Pask and Norbert Wiener, and the possibilities of the computer and the "new science" it has facilitated, Frazer and his team of collaborators have conducted a series of experiments that utilize genetic algorithms, cellular automata, emergent behaviour, complexity and feedback loops to create a truly dynamic architecture. Frazer studied at the Architectural Association (AA) in London from 1963 to 1969, and later became unit master of Diploma Unit 11 there. He was subsequently Director of Computer-Aided Design at the University of Ulter - a post he held while writing An Evolutionary Architecture in 1995 - and a lecturer at the University of Cambridge. In 1983 he co-founded Autographics Software Ltd, which pioneered microprocessor graphics. Frazer was awarded a person chair at the University of Ulster in 1984. In Frazer's hands, architecture becomes machine-readable, formally open-ended and responsive. His work as computer consultant to Cedric Price's Generator Project of 1976 (see P84)led to the development of a series of tools and processes; these have resulted in projects such as the Calbuild Kit (1985) and the Universal Constructor (1990). These subsequent computer-orientated architectural machines are makers of architectural form beyond the full control of the architect-programmer. Frazer makes much reference to the multi-celled relationships found in nature, and their ongoing morphosis in response to continually changing contextual criteria. He defines the elements that describe his evolutionary architectural model thus: "A genetic code script, rules for the development of the code, mapping of the code to a virtual model, the nature of the environment for the development of the model and, most importantly, the criteria for selection. In setting out these parameters for designing evolutionary architectures, Frazer goes beyond the usual notions of architectural beauty and aesthetics. Nevertheless his work is not without an aesthetic: some pieces are a frenzy of mad wire, while others have a modularity that is reminiscent of biological form. Algorithms form the basis of Frazer's designs. These algorithms determine a variety of formal results dependent on the nature of the information they are given. His work, therefore, is always dynamic, always evolving and always different. Designing with algorithms is also critical to other architects featured in this book, such as Marcos Novak (see p150). Frazer has made an unparalleled contribution to defining architectural possibilities for the twenty-first century, and remains an inspiration to architects seeking to create responsive environments. Architects were initially slow to pick up on the opportunities that the computer provides. These opportunities are both representational and spatial: computers can help architects draw buildings and, more importantly, they can help architects create varied spaces, both virtual and actual. Frazer's work was groundbreaking in this respect, and well before its time.

The role of natural ventilation in building sustainable subdivisions in south east Queensland

The objective of the consultative phase is to examine the role that natural ventilation has and can play in the subdivision planning process in SEQ. The Centre for Subtropical Design at QUT coordinated the consultative phase and has conducted a workshop, and interviews, with stakeholders including developers, land development consultants, land surveyors, urban designers and regulators, to identify current understanding of the impact of urban subdivision on natural ventilation, and the role of natural ventilation in achieving energy efficiency for dwellings. This report details the findings.

Report : effect of natural cleaning on salt deposition on Queensland bridges

Maintenance of bridge structures is a major issue for the Queensland Department of Main Roads. In the previous phase of this CRC project an initial approach was made towards the development of a program for lifetime prediction of metallic bridge components. This involved the analysis of five representative bridge structures with respect to salt deposition (a major contributor to metallic corrosion) to determine common elements to be used as “cases” - those defined for buildings are not applicable. The five bridges analysed included the Gladstone Port Access Road Overpass, Stewart Road Overpass, South Johnstone River Bridge, Johnson Creek Bridge and the Ward River Bridge.

The impact of natural disasters on residential property markets

Over the past ten years various residential property markets throughout Australia in general and NSW in particular have been subject to substantial natural disasters. These occurrences have included floods, bushfires and hailstorms. In extreme cases the actual rectification costs have been up to AUD$1.5 billion, which occurred with the severe hailstorm in Sydney in April 1999 and cyclone Tracey in Darwin in 1974. Natural disasters such as severe storms and hailstorms have tended to be very indiscriminate in relation to frequency and the actual location of damage, whereas the nature of bushfire and flooding tends to be more defined. Although these extreme natural disasters tend to be infrequent, occurrences of floods and bushfires in residential property areas are more frequent, particularly as urban sprawl encroaches closer to national Parks, State recreation Parks and State forests. Considerable work has been carried out on flood effects on property markets by Bell (1999), Donnelly (1988), McClusky and Rausser (2001), Skrantz and Strickland (1987) in the US, and Chou and Shih (2001) in Taiwan. Fibbens (1994), Lambley and Cordery (1991) and Eves (1999, 2001, 2002) have carried out studies in relation to the effect of flooding on residential property values in the Sydney region, including the tracking of flood prone property values over time. However, no similar rigorous research has been carried out in relation to the impact of bushfires on residential property markets in the Sydney region.

Electron paramagnetic resonance spectral studies on natural sapphire

EPR study of both blue and green sapphire samples confirms the presence of Cr(III) in four different octahedral sites. The g (1.98) value is the same but D values differ for the two the samples. The EPR spectra suggest that the blue sapphire contains more chromium than the green sapphire. No Fe(III) impurity was noted in the EPR spectrum.

Natural enemies of Paropsis atomaria Olivier (Coleoptera: Chrysomelidae) in south-eastern Queensland eucalypt plantations

Abstract A field survey for natural enemies of Paropsis atomaria was conducted at two south-eastern Queensland Eucalyptus cloeziana plantation sites during 2004–2005. Primary egg and larval parasitoids and associated hyperparasitoids were identified to genus or species, and parasitism rates were determined throughout the season. Predators were identified to family level but their impact was not quantified. P. atomaria adults were also examined as potential hosts for parasitic mites and nematodes. An undescribed species of Neopolycystus (Pteromalidae) was the major primary egg parasitoid species reared from egg batches, parasitising half of all egg batches collected. Three hyperparasitoid species (Baeoanusia albifunicle (Encyrtidae), Neblatticida sp. (Encyrtidae) and Aphaneromella sp. (Platygasteridae) were present, representing around one-quarter to one-third of all emergent wasps; this is the first host association record for Neopolycystus–B. albifunicle. In contrast to populations of P. atomaria from the Australian Capital Territory, primary larval parasitism was very low, around 1%, and attributable only to the tachinid flies Anagonia sp. and Paropsivora sp. However, the presence of the sit-and-wait larval hyperparasitoid, Perilampus sp. (Perilampidae) was high, emerging from around 17% of tachinid pupae, with planidia infesting a further 40% of unparasitised hosts. Three species of podapolipid mites parasitised sexually mature P. atomaria adults, while no nematodes were found in this study. Spiders were the most common predators and their abundance was positively correlated with P. atomaria adult and egg numbers. Although natural enemy species composition was identical between our two study sites, significant differences in abundance and frequency were found between sites