1,662 research outputs found
Cenários futuros para cana-de-açucar no Estado de São Paulo.
Com a atual contribuição econômica e tecnológica alcançada pelo setor canavieiro no Brasil é de altíssima importância a preocupação sobre os cenários futuros na agricultura e avaliação do impacto gerado pelas mudanças climáticas. Sobre a vulnerabilidade dos sistemas agrícolas, conseqüentemente, torna se de grande utilidade para o planejamento de médio e longo prazo do setor no País, adaptando-se aos possíveis impactos e observando as diferenças regionais quanto aos efeitos da mudança no clima. Portanto a necessidade de estudos com modelagem e análise de dados visando à avaliação dos possíveis impactos das mudanças climáticas sobre atividades humanas, recursos naturais e, particularmente, sobre a agricultura brasileira contém enormes valores econômicos e sociais com grande potencial de impacto no desenvolvimento nacional.Trabalho apresentado na V Mostra de Trabalhos de Estagiários e Bolsistas, Campinas, out. 2009
O eletromagnetismo no contexto de um sistema elétrico : uma abordagem apoiada no enfoque Ciência - Tecnologia - Sociedade
Environmental fate of pesticides applied on coffee crops in southeast of Brazil
The aim of this paper was evaluate the environmental fate of pesticides applied in coffee crops in southeast of Brazil, using the level I fugacity model. Chemical and physical characteristics of the pesticides were considered in different environmental compartments and applied fugacity equations. The preliminary evaluation of contamination risk due the use of pesticides in coffee crops, using fugacity models, proved to be good tools to be used in the process of making decision to select pesticides with less impact on the environment, as well to prioritize the pesticides to be monitored. For most of the pesticides evaluated, the soil/sediment compartment was the most vulnerable.Key words: Environmental fate, fugacity, organic micropollutants, pesticide
Sustainable development aspects of biodiesel production and application in Brazil
Concerns about climate change effects have prompted many countries to search for solutions to reduce fossil fuel consumption. In the last few years biodiesel production has gained world attention, as it is seen as a sustainable and renewable energy source. Biodiesel is a natural substitute for diesel oil, and can be obtained from different oleaginous plants. However, there are worries about devastation of forests and biodiversity-rich areas to produce biodiesel. Even considering biodiesel as a promising solution, the impacts of its production must be carefully evaluated. This work examines the Brazilian scenario for biodiesel production and use as an automotive fuel. Native and adapted oleaginous in many Brazilian regions and their potentiality for biodiesel production are presented. Experimental results of hydrocarbons (HC), carbon monoxide (CO), and carbon dioxide (CO2) emissions from a diesel power generator fuelled by blends of diesel oil and castor oil or soybean biodiesel are also presented
Further developments on biodiesel production and applications in brazil
Environmental concerns have motivated many countries to search for solutions to reduce fossil fuel consumption. In the last few years, biodiesel has attracted attention as a possible sustainable and renewable energy source to substitute diesel oil. Biodiesel can be produced from different oleaginous plants, but there are worries about food competition and forests and biodiversity-rich areas devastation to produce biodiesel. Even considering biodiesel as a promising solution, its production impacts must be carefully evaluated. This work examines the Brazilian prospects for biodiesel production and use as an engine fuel for automotive propulsion and power generation. The potential for biodiesel production of many native and adapted oleaginous plants in Brazilian territory is discussed. Experimental results of hydrocarbons, carbon monoxide, and carbon dioxide emis-sions from a diesel power generator fuelled by blends of diesel oil and castor oil or soybean biodiesel are also presented
Measuring AGN Feedback with the Sunyaev-Zel'dovich Effect
One of the most important and poorly-understood issues in structure formation
is the role of outflows driven by active galactic nuclei (AGN). Using
large-scale cosmological simulations, we compute the impact of such outflows on
the small-scale distribution of the cosmic microwave background (CMB). Like
gravitationally-heated structures, AGN outflows induce CMB distortions both
through thermal motions and peculiar velocities, by processes known as the
thermal and kinetic Sunyaev-Zel'dovich (SZ) effects, respectively. For AGN
outflows the thermal SZ effect is dominant, doubling the angular power spectrum
on arcminute scales. But the most distinct imprint of AGN feedback is a
substantial increase in the thermal SZ distortions around elliptical galaxies,
post-starburst ellipticals, and quasars, which is linearly proportional to the
outflow energy. While point source subtraction is difficult for quasars, we
show that by appropriately stacking microwave measurements around early-type
galaxies, the new generation of small-scale microwave telescopes will be able
to directly measure AGN feedback at the level important for current theoretical
models.Comment: 12 pages, 12 figures, submitted to ApJ (comments welcome
- …