939 resultados para Earth and Environment
Resumo:
In northern China, the loess-soil sequence of the last 2.6 Ma, the Hipparion Red-Earth of eolian origin and recently reported Pliocene-Miocene loess-soil sequence provide a near continuous continental eolian record of climatic history for the past 22.0 Ma. This work aims to investigate the composition and structure of clay minerals contained in deposits, and to explore their implications for environmental evolutions over the last 22.0 Ma. Clay minerals, which were extracted from eolian samples collected at Xifeng (0-6.2 MaBP) and Qinan (6.2-22.0 MaBP) sections, were analyzed qualitatively and semi-quantitatively by using X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetric analysis (TG) and chemical analysis. The main conclusions are as follows: Over the last 22.0 Ma, the clay mineral assemblage among Quaternary loess-soils, Hipparion Red-Earth, and Miocene loess-soils shows similar components, mainly consisting of illite (55-80%), kaolinite (7-20%), chlorite (4-13%), smectite (2-23%) as results calculated by comparing major peak areas. There are no obvious differences in both types and amounts of clay minerals between loess and interbedded soils, suggesting that overwhelming part of the clay minerals is derived from the source. According to the components of clay minerals, the whole sequence of eolian deposits in the Loess Plateau can be divided into ten clay mineral assemblage zones over the last 22.0 Ma, whose corresponding ages are: 22.0-21.0 MaBP, 21.0-18.0 MaBP, 18-16.2 MaBP, 16.2-13.0 MaBP, 13.0-10.0 MaBP, 10.0-5.5 MaBP, 5.5-4.4 MaBP, 4.4-2.8 MaBP, 2.8-1.0 MaBP, 1.0-0 MaBP, respectively. This may imply that dust supply changed at least nine times over the past 22.0 Ma. The loess illite has a better crystaliinity, higher value of the FWHM and IC, than the interbedd soils. Previous studies indicated that irregular mixed layer minerals could form under relatively warm and humid conditions (Han, 1982). According to the general distribution of clay minerals of zonal soil (Chamley, 1989), the clay mineral assemblage of eolian deposits in Xifeng and Qinan sections is typical of temperature-humid and warm-subarid environment. Therefore, our results indicate climatic environment in Loess Plateau did not change remarkably since 22.0 Ma, and fluctuated between temperature-humid and warm-subarid climate. 4. The illite generally presents poorer crystaliinity during the period of 22.0 to 2.8 MaBP than in the last 2.8 Ma BP, especially at the intervals of 3.5-4.5 Ma BP, 14.0-17.0 MaBP and 20.0-22.0 Ma BP, which indicates that the weathering intensity was stronger in Neogene than in Quaternary. 5. The relatively low ice volume and high global temperature may be responsible for the strange weathering intensity during the interval of the 3.5-4.5 Ma BP, 14.0-17.0 Ma BP and 20.0-22.0 Ma BP.
Resumo:
Window design plays an important role in achieving energy efficient buildings and in providing thermal comfort of building occupants. This paper investigates a newly developed aerogel window and the potential improvement on the comfort factors of an office in relation to daylighting. Improved comfort levels can impact on health and wellbeing of building occupants leading to knock on effects on absenteeism and productivity. A simulation tool was presently created that will easily enable comparison of different façade design and their impact on heat and light transmission and therefore enable optimisation. One of the most important aspects of the present work was comparing the performance of the newly developed aerogel window against the more traditional Argon-filled, coated double-glazing. Whereas the aerogel window provided an extremely low heat-loss index of 0.3 W/m2K, the latter usually offered a centre-glazing U-value of 1.4 W/m2K. On a like-with-like basis the daylight transmission of the aerogel window was significantly lower than double-glazing. However, in view of low thermal loss larger areas of the former can be deployed. This article presents the influence of three key parameters that may lead to an optimum design: daylight, thermal loss and solar gain.
Resumo:
Huws, Catrin, 'Rural Housing, Affordable Housing and Speaking the Language of an Unaffordable Hearth', Journal of Planning and Environment Law, (2007) pp.1648-1660 RAE2008
Resumo:
Wilding, M. C., Benmore, C. J. (2006). Structure and Glasses and Melts. reviews in Mineralogy and Geochemistry, 63 (1), 275-311 RAE2008
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The fundamental phenotypes of growth rate, size and morphology are the result of complex interactions between genotype and environment. We developed a high-throughput software application, WormSizer, which computes size and shape of nematodes from brightfield images. Existing methods for estimating volume either coarsely model the nematode as a cylinder or assume the worm shape or opacity is invariant. Our estimate is more robust to changes in morphology or optical density as it only assumes radial symmetry. This open source software is written as a plugin for the well-known image-processing framework Fiji/ImageJ. It may therefore be extended easily. We evaluated the technical performance of this framework, and we used it to analyze growth and shape of several canonical Caenorhabditis elegans mutants in a developmental time series. We confirm quantitatively that a Dumpy (Dpy) mutant is short and fat and that a Long (Lon) mutant is long and thin. We show that daf-2 insulin-like receptor mutants are larger than wild-type upon hatching but grow slow, and WormSizer can distinguish dauer larvae from normal larvae. We also show that a Small (Sma) mutant is actually smaller than wild-type at all stages of larval development. WormSizer works with Uncoordinated (Unc) and Roller (Rol) mutants as well, indicating that it can be used with mutants despite behavioral phenotypes. We used our complete data set to perform a power analysis, giving users a sense of how many images are needed to detect different effect sizes. Our analysis confirms and extends on existing phenotypic characterization of well-characterized mutants, demonstrating the utility and robustness of WormSizer.
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Computer based analysis of evacuation can be performed using one of three different approaches, namely optimisation, simulation or risk assessment. Furthermore, within each approach different means of representing the enclosure, the population, and the behaviour of the population are possible. The myriad of approaches which are available has led to the development of some 22 different evacuation models. This article attempts to describe each of the modelling approaches adopted and critically review the inherent capabilities of each approach. The review is based on available published literature.
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Embedded electronic systems in vehicles are of rapidly increasing commercial importance for the automotive industry. While current vehicular embedded systems are extremely limited and static, a more dynamic configurable system would greatly simplify the integration work and increase quality of vehicular systems. This brings in features like separation of concerns, customised software configuration for individual vehicles, seamless connectivity, and plug-and-play capability. Furthermore, such a system can also contribute to increased dependability and resource optimization due to its inherent ability to adjust itself dynamically to changes in software, hardware resources, and environment condition. This paper describes the architectural approach to achieving the goals of dynamically self-configuring automotive embedded electronic systems by the EU research project DySCAS. The architecture solution outlined in this paper captures the application and operational contexts, expected features, middleware services, functions and behaviours, as well as the basic mechanisms and technologies. The paper also covers the architecture conceptualization by presenting the rationale, concerning the architecture structuring, control principles, and deployment concept. In this paper, we also present the adopted architecture V&V strategy and discuss some open issues in regards to the industrial acceptance.
Resumo:
Urban spectacles such as the Olympic Games have been long perceived as being able to impose desired effects in the city that act as host. This kind of urban boost may include the creation of new jobs and revenue for local community, growth in tourism and convention business, improvements to city infrastructure and environment, and the stimulation of broad reform in the social, political and institutional realm. Nevertheless at the other end of the debate, the potentially detrimental impacts of Olympic urban development, particularly on disadvantaged and vulnerable groups, have also been increasingly noticed in recent years and subsequently cited by a number of high profile anti-Olympic groups to campaign against Olympic bids and awards. The common areas of concern over Olympic-related projects include the cost and debts risk, environmental threat, the occurrence of social imbalance, and disruption and disturbance of existing community life. Among these issues, displacement of low income households and squatter communities resulting from Olympic-inspired urban renewal are comparatively under-explored and have emerged as an imperative area for research inquiry. This is particularly the case where many other problems have become less prominent. Changing a city’s demographic landscape, particularly displacing lower income people from the area proposed for a profitable development is a highly contentious matter in its own right. Some see it as a natural and inevitable outgrowth of the process of urban evolution, without which cities cannot move towards a more attractive location for consumption-based business. Others believe it reflects urban crises and conflicts, highlighting the market failures, polarization and injustice. Regardless of perception,these phenomena are visible everywhere in post-industrial cities and particularly cannot be ignored when planning for the Olympic Games and other mega-events. The aim of this paper is to start the process of placing the displacement issue in the context of Olympic preparation and to seek a better understanding of their interrelations. In order to develop a better understanding of this issue in terms of cause, process, influential factors and its implication on planning policy, this paper studies the topic from both theoretic and empirical angles. It portrays various situations where the Olympics may trigger or facilitate displacement in host cities during the preparation of the Games, identifies several major variables that may affect the process and the overall outcome, and explores what could be learnt in generic terms for planning Olympic oriented infrastructure so that ill-effects to the local community can be effectively controlled. The paper concludes that the selection of development sites, the integration of Olympic facilities with the city’s fabric, the diversity of housing type produced for local residents and the dynamics of the new socioeconomic structure.
Resumo:
The Fal Estuary System in West Cornwall has, over many centuries, received inputs of heavy metals from various mining activities. In this context its most important tributary is the Carnon River. Analyses of organisms from the Fal Estuary have shown that some species contain abnormally high concentrations of Cu, Zn and As, especially those living in Restronguet Creek.