This research has three parts. Part 1: The Policy on Geometric Design of Highways and Street provides 5 methods of superelevation (e) distribution. Many states use methods 2 and 5 for low speed, urban and rural high-speed facilities. Method 5 aims to address speed variations; but is complicated, computationally intractable and may violate design consistency. Design recommendation by NCHRP439 accounts for speed variation, tractable; but is cumbersome along with irregular/step-wise design curves. New reliability based e distribution method is developed that addresses the speed variation; which is simple in determining and evaluating acceptable required e rates. At 95% level of reliability, the e rate obtained is lower than that from current practice resulting in cost savings. Part 2: Current practice/research does not address safety issue of the left-turn-bay at high degree of saturation (x). Left-Turn-Bay distance has three components: clearance, breaking to a stop and queue. The variation in the queue length reduces clearance and breaking distance resulting in unsafe breaking. Failure = clearance plus breaking distance < demand. The reliability of the left-turn-bay defined as the availability of the three components for left-turning vehicles to complete clearance and breaking maneuver safely; measured as increase in the deceleration rate over limit of 11.2ft/s2, safety index and probability of failure. Results show that at 95% reliability, current design practice fails when x exceeds 50%. Part 3: Current practice uses mean traffic volumes (Vd) as input for traffic signal control at roadway intersections. Variations in traffic flows affect the performance of intersection measured by the delay per vehicle traversing the intersection in seconds. Peak hour factor (PHF), the hourly volume divided by the peak 15-min flow rate within the peak hour is adopted by Highway Capacity Manual (HCM) to control surge. HCM suggests PHF design value of 0.92 for urban and 0.88 for rural areas. Fixed PHF may lead to increase in delay. Effects of variation of peak hour volumes on intersection signal delays are examined with large data. A new model is developed for PHF and Vd and used in signal timing to minimize intersection delay. The results show that the assumption of Poisson distribution for Vd is not reliable; delay reduction of 6.2 seconds per vehicle is achieved. Annual savings in travel time, fuel consumption and emissions cost is estimated in billions of dollars.

The distribution of benthic polychaetes in the Mississippi Canyon was examined to evaluate impacts of environmental variables on species assemblages. Environmental variables considered included depth, bathymetric slope, hydrographic features, sediment grain size, food availability and sediment contamination. Samples were collected using GOMEX boxcorer. Density decreased with increasing depth exponentially. Diversity exhibited a unimodal pattern with depth with a maximum value in the intermediate depth range (about 1269 m). Deposit feeders were the most abundant feeding guild. Both the feeding guilds and faunal composition could be divided into three groups along the depth gradient: shallow (300 – 800 m), intermediate (800 – 1500 m) and deep (> 1500 m). Results of statistical analyses revealed that depth was the most important determinant in organizing polychaete assemblages in the study area. The Mississippi Canyon and the Central Transect (a non-canyon area) were found not contaminated by trace metals or Polynuclear Aromatic Hydrocarbons (PAHs) in sediments, although the highest PAHs concentration occurred at the head of the Canyon, MT1. The mean density was higher in the Mississippi Canyon (1668 N/m2) than in the Central Transect (979 N/m2), while the mean diversity in the Canyon (ES(100) = 26.9 ) was lower than the Central Transect (ES(100) = 33.1). Large amounts of terrigenous input from the Mississippi River to the Canyon could enhance polychaete density and accelerate competitive exclusion, and thus lead to lower diversity. The faunal composition was significantly different between the two transects, with higher species richness in the Mississippi Canyon (301 species). This could be attributed to structure complexity in the Mississippi Canyon. The distribution of feeding guilds was similar between two transects. The differences observed in polychaete assemblages between two transects may be largely due to high terrigenous sediment and organic matter input to the Mississippi Canyon by the Mississippi River.

Made available in DSpace on 2014-10-09T12:26:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:20Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:26:43Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:20Z (GMT). No. of bitstreams: 0 / A interferência antrópica no meio ambiente e conseqüente alteração do clima, é hoje um consenso. Esta interferência climática se dá de forma local, regional e, conjuntamente com os gases de efeito estufa, de forma também global. Essa alteração climática, de maneira reversa, interfere por sua vez, no meio ambiente. Tal ciclo de interferências se processa sob várias formas e resulta em várias conseqüências. Porém o chamado Aquecimento Global é, certamente, o efeito de conseqüências globais de maior impacto. A causa principal do aumento da temperatura (Efeito Estufa) está no uso intensivo que se faz de energéticos fósseis. Assim, para minimizar as mudanças climáticas deve-se focar o esforço principalmente em ações que visem à diminuição, substituição e o uso mais eficiente dos energéticos fósseis. Olhando para o passado, parece que os antigos agricultores podem ter lançado gases estufa desde milênios atrás, alterando de maneira lenta, mas significativa, o clima do planeta muito antes do que na Era Industrial. Confirmada essa teoria, suas conseqüências seriam decisivas para a história do homem na Terra. Por exemplo, as temperaturas atuais de partes da América do Norte e Europa poderiam ser até 4 graus Celsius menores, o suficiente para inviabilizar nessas áreas, a agricultura e, conseqüentemente, o desenvolvimento humano e histórico dessas regiões. Este trabalho tem como foco principal fazer uma retrospectiva sobre algumas culturas que colapsaram frente a problemas ambientais e fazer um histórico das atividades humanas ao longo do tempo, desde os primórdios do homem até a Revolução Industrial, notadamente com o que diz respeito à vi agricultura e pecuária, no sentido da sua interferência na dinâmica natural do clima global e no meio ambiente. Mostrando, através de comparações de dados e inferências, que as emissões dessas atividades tiveram uma magnitude até significativa, comparativamente as mudanças induzidas após a própria Revolução Industrial. Demonstra-se, também, que essa interferência climático-ambiental era inevitável, no sentido que a evolução humana deveu-se a essas mesmas atividades. Outro ponto importante é uma reflexão sobre como a evolução humana (e conseqüentemente sua ciência e tecnologia) irá, porventura, encontrar as soluções dos problemas causados por essas mudanças climáticas e ambientais e a importância, neste contexto, para as soluções de problemas de ordem social / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Impactos no Meio Físico decorrentes da construção de barragens e enchimento de reservatórios e as possíveis soluções aplicáveis com vistas a eliminá-los ou mitigá-los. Apresentados também os programas de monitoramento dos aspectos físicos afetados, com freqüência e duração das observações. / This Dissertation aims the presentation of a general analysis of the environmental physical impacts arised from the construction of dams and the creation of reservoirs. Presents also the suggestion of a series of measures to be implemented in order to avoid or to mitigate those impacts and the subjects that would be monitored.

In the last couple of decades, there has been an increased awareness of the effects that electricity generation has on the environment through the emission of greenhouse gases and the depletion of natural resources. This realisation, coupled with an increased drive towards ensuring the sustainability of the energy supply system, has lead many, including the United Kingdom government to investigate the options for moving away from traditional fossil fuel-burning generation methods towards “lowcarbon” generators, such as renewables and nuclear power. Specifically, wind power, the more mature systems (with the exception of hydro power) of the available renewable energy supply, and nuclear power, a technology seen as producing large amounts of electricity with very few associated greenhouse emissions, have been promoted but also pitted against each other by analysts and policy makers. This work aims to provide a balanced analysis of wind power and nuclear power with respect to their effects on the natural environment. As such, modeling has been undertaken of a Generation III+ nuclear reactor, an onshore wind farm located in southern Scotland and an offshore wind farm near the Thames estuary while environmental indicators have been created to permit the comparative assessment of these three electricity generation technologies, in a U.K. context. These indicators thus facilitate an assessment of the energy requirements, the associated greenhouse gas emissions, the natural resource requirements, as well as the displaced carbon dioxide emissions from operation of each power plant. A parametric analysis has also been conducted to show the range of likely variations in each indicator’s values. The results of this research show that all three technologies demonstrate similar performance with respect to their energetic and environmental impacts. More specifically, the wind farms demonstrate better energy gain ratios than the nuclear power plant when they are credited for not depleting non-renewable fuel sources. The wind farms also are shown to pay back their energy investments faster than the nuclear power plant. On the other hand, the nuclear power plant is found to produce slightly lower greenhouse gas emissions than either onshore or offshore wind farms. With respect to the assessment of natural resource depletion, it is estimated that both wind farms need more land per unit of electricity produced than the nuclear power plant, but all three power plants permanently sequester similar amounts of water. The wind farms and the nuclear power plant are found to have similar performance with respect to their material requirements, while the calculation of the avoided emissions factors for all technologies are of similar orders of magnitude. All results are shown to be highly sensitive to the assumptions made about the prospective lifecycles, and as such caution should be exercised when drawing conclusions about any comparative advantages. Nethertheless both technologies are clearly shown to have lower environmental impacts than traditional electricity generation technologies.

Este trabalho tem por objetivo quantificar o impacto da vegetação nos microclimas urbanos abaixo do dossel, em função das interações solo-vegetação-atmosfera. Essas interações consideram os efeitos: 1) do dossel propriamente dito, expressos pelas variáveis índice de área foliar - IAF (Leaf Area Index - LAI) e distribuição geométrica das aberturas na copa (gap fraction); 2) da cobertura do solo, expressa pela composição do solo, sua temperatura e teor de umidade, e 3) das variáveis microclimáticas locais (temperatura do ar, umidade do ar, radiação solar, temperatura radiante media, temperatura superficial, direção e velocidade dos ventos). Considerando-se que o impacto da vegetação nos microclimas urbanos é função das interações solo-vegetação-atmosfera, e tendo em vista resultados de estudos anteriores, a hipótese deste trabalho é que, para o clima de São Paulo, em função dos processos de evapotranspiração e do sombreamento, a redução na temperatura do ar abaixo do dossel em parques urbanos será de cerca de 1o C e a redução da temperatura superficial será de cerca de 20oC, ambas em relação às áreas não sombreadas pela vegetação, e que esses efeitos limitam-se à borda do parque sob condições de baixa velocidade do vento, de cerca de 1 m/s. O método é 1) indutivo, por meio de medições de campo durante o período de dias quentes e frios no Parque Tenente Siqueira Campos (Trianon), na cidade de São Paulo, para o registro de dados microclimáticos e para o levantamento das variáveis do dossel e do solo; e 2) dedutivo, com a calibração entre dados medidos e simulados pelo modelo ENVI-met 3.1 Beta 5 e a simulação de diferentes cenários, variando-se as características do dossel. Para se estimar a densidade foliar média das copas foram adotados dois métodos não-destrutivos indiretos: a medição do IAF com o equipamento LAI-2000 (LI-COR) e a análise das fotos hemisféricas, utilizando-se o aplicativo Can-Eye. De acordo com os resultados das simulações, variando-se as caraterísticas do dossel, verificou-se uma redução máxima de 1ºC na temperatura do ar e de 19°C na temperatura superficial, ao se comparar os valores obtidos abaixo de uma copa densa (forma elíptica e IAF 5m2/m2) em relação às condições do entorno, fora do parque. Esse efeito se estende por, no máximo, 5m de distância a partir dos limites do parque, com velocidade do ar de 1m/s e umidade de 40% na camada superficial do solo (0-20cm). Foi feita a aplicação do TEP - Temperatura Equivalente Percebida e verificou-se que a redução de 1°C na temperatura do ar pode representar de 3°C a 5°C no conforto térmico das pessoas. Esses resultados comprovam a hipótese inicial e mostram não apenas a importância do tipo de vegetação escolhida (formato da copa, IAF e distribuição geométrica das aberturas na copa) como as características do meio em que ela está inserida (condições microclimáticas locais e de solo). Os resultados podem contribuir para a formulação de políticas públicas visando à mitigação dos efeitos de aquecimento urbano, particularmente diurnos, em climas tropicais. / The objective of this work is to quantify the impact of vegetation on urban microclimates, under the canopy, due to soil-vegetation-atmosphere interactions. It considers the following effects: 1) the canopy itself, expressed by the variable leaf area index - LAI and the geometric openness distribution in the canopy (gap fraction); 2) the soil coverage, expressed by soil composition, soil temperature and soil humidity, and 3) the local microclimatic variables (air temperature, humidity, solar radiation, mean radiant temperature, surface temperature, wind direction and wind speed). Considering the impact of vegetation on urban microclimates as a function of soil-vegetation-atmosphere, and based on the outcomes of preview studies, this work starts from the hypothesis that for São Paulo climate and as a result of evapotranspiration and shadowing process, the reduction of air temperature under the canopy will be between 1°C to 2°C and for surface temperature, it will be around 20°C, both in relation to an area without tree shadowing. These effects are restricted to the borders of the park, especially under the conditions of low wind speed, approximately 1m/s. The methods are: 1) inductive, based on field measurements in summer and winter at Tenente Siqueira Campos Park (Trianon Park), in the city of São Paulo, registering microclimatic data and collecting information for canopy and soil; and 2) deductive, with the calibration of measured and simulated data by ENVI-met 3.1 Beta 5 and the simulation for different scenarios varying the canopy characteristics. To estimate the average leaf density for trees canopy two no-destructive indirect methods were applied: measurement of LAI using the equipment LAI-2000 (LI-COR) and the analysis of hemispheric photographs, using a software application Can-Eye. According to the simulation results, for different characteristics for canopy, it could be verified a maximum reduction of 1ºC in air temperature and 19°C for surface temperature, when comparing the obtained value under a dense canopy (elliptical form and LAI of 5m2/m2) to the conditions on the street. The maximum extension of these effects were up to 5m from the limits of the park, considering 1m/s for wind speed and 40% for soil humidity in the upper layer (0-20cm). The thermal index TEP calculated and it could be seen that the reduction of 1°C for air temperature can represent from 3°C to 5°C in terms of thermal comfort of people. By these results, the initial hypothesis has proven to be correct and showed not only the importance of the type of vegetation selected (canopy form, LAI values and geometric distribution of canopy openness) but also the characteristics of the surrounding environment (microclimatic and soil conditions). Furthermore, it will contribute to formulate public politics aiming to mitigate urban warming effect, mainly during daytime, in tropical cities.