165 research outputs found
Ecological Connectivity Research in Urban Areas
No full textThe successful movement of individuals is fundamental to life. Facilitating these movements by promoting ecological connectivity has become a central theme in ecology and conservation. Urban areas contain more than half of the world's human population, and their potential to support biodiversity and to connect their citizens to nature is increasingly recognized. Promoting ecological connectivity within these areas is essential to reaching this potential. However, our current understanding of ecological connectivity within urban areas appears limited.We reviewed the published scientific literature to assess the state-of-the-art of ecological connectivity research in urban areas, summarized trends in study attributes and highlighted knowledge gaps.We found 174 papers that investigated ecological connectivity within urban areas. These papers addressed either structural (48) or functional connectivity (111), and some addressed both (15), but contained substantial geographic and taxonomic biases. These papers rarely defined the aspect of connectivity they were investigating and objective descriptions of the local urban context were uncommon. Formulated hypotheses or a priori predictions were typically unstated and many papers used suboptimal study designs and methods.We suggest future studies explicitly consider and quantify the landscape within their analyses and make greater use of available and rapidly developing tools and methods for measuring functional connectivity (e.g. biotelemetry or landscape genetics). We also highlight the need for studies to clearly define how the terms ‘urban’ and ‘connectivity’ have been applied.Knowledge gaps in ecological connectivity in urban areas remain, partly because the field is still in its infancy and partly because we must better capitalize on the state-of-the-art technological and analytical techniques that are increasingly available. Well-designed studies that employed high-resolution data and powerful analytical techniques highlight our abilities to quantify ecological connectivity in urban areas. These studies are exemplary, setting the standards for future research to facilitate data-driven and evidence-based biodiversity-friendly infrastructure planning in urban areas
Effects of Roads and Traffic on Wildlife Populations and Landscape Function: Road Ecology is Moving toward Larger Scales
No full textRoad ecology has developed into a significant branch of ecology with steady growth in the number of refereed journal articles, books, conferences, symposia, and "best practice" guidelines being produced each year. The main objective of this special issue of Ecology and Society is to highlight the need for studies that document the population, community, and ecosystem-level effects of roads and traffic by publishing studies that document these effects. It became apparent when compiling this special issue that there is a paucity of studies that explicitly examined higher order effects of roads and traffic. No papers on landscape function or ecosystem-level effects were submitted, despite being highlighted as a priority for publication. The 17 papers in this issue, from Australia, Canada, the Netherlands, and USA, all deal to some extent with either population or community-level effects of roads and traffic. Nevertheless, many higher order effects remain unquantified, and must become the focus of future studies because the complexity and interactions among the effects of roads and traffic are large and potentially unexpected. An analysis of these complex interrelations requires systematic research, and it is necessary to further establish collaborative links between ecologists and transportation agencies. Many road agencies have "environmental sustainability" as one of their goals and the only way to achieve such goals is for them to support and foster long-term and credible scientific research. The current situation, with numerous small-scale projects being undertaken independently of each other, cannot provide the information required to quantify and mitigate the negative effects of roads and traffic on higher levels. The future of road ecology research will be best enhanced when multiple road projects in different states or countries are combined and studied as part of integrated, well-replicated research projects
Transport Verschijnselen in Vallende-Film Absorbers van het Plaat-Vin Type
No full textMechanical Maritime and Materials Engineerin
Metamorfosen: Beeldtypen van architectuur en landschap
No full textHet landschapstheater omvat een veel grotere rijkdom aan decors, zetstukken en requisieten, dan er in een catalogus valt te etaleren. Toch hebben wij geprobeerd in deze eerste voorlopige versie van het boekje om een aantal van zulke beeldtypen te documenteren en de grenzen ervan af te tasten. Voor de voorbeelden hebben wij vrij geput uit onze eigen ervaring. Het is de bedoeling dat wijzelf en alle gebruikers dit boekje blijven herzien en aanvullen met eigen beeldelementen en fascinaties. Deze beeldencatalogus kan het best gebruikt worden naast het handboek Architectuur en Landschap waarin landschapsarchitectonische compositie- en ensceneringstechnieken zijn behandeld. In het bijzonder wordt deze catalogus ontwikkeld als hulpmiddel en inspiratiebron bij de ontwerpopgaven in de D 3 differentiatiemodule Architectuur en Landschap. Maar ook alle andere ontwerpstudenten en geïnteresseerden bieden wij dit materiaal gaarne aan, als inspiratiebron en ter creatieve bewerking, aanvulling en becommentariëring.UrbanismArchitectur
Modeling of indoor thermal conditions for comfort control in buildings
No full textMechanical Maritime and Materials Engineerin
Simultaneous heat and mass transfer in a horizontal tube absorber: Numerical tools for present and future absorber designs
No full textMechanical Maritime and Materials Engineerin
Fluidized bed ice slurry generator for enhanced secondary cooling systems
No full textIce slurries are liquid solutions of a freezing point depressant in water, in which small ice crystals are present. Ice slurries are efficient secondary cooling fluids because they utilize the latent heat effect involved with the ice/water phase change. A high heat capacity is available at relatively constant temperatures, while ice slurries are also pumpable. Furthermore, ice slurries can be stored in tanks for later use, which allows for benefits of peak load reduction and also allows for shifting of cooling loads to the nighttime, when electricity tariffs are low and the primary cycle efficiency is high. Ice slurries may for example be utilized in air-conditioning, supermarket cooling and cooling in (food) industry. The objective of the research was to enhance secondary cooling system performance by using a fluidized bed ice slurry generator. The research was initiated because ice slurries, though efficient cold carriers, are not applied widely in secondary cooling systems yet, the main obstacle being the lack of an efficient ice slurry generator. In the research the heat and mass transfer processes in the fluidized bed ice slurry generator were studied in detail. An accurate heat transfer model was developed. Ice crystallization, ice adhesion and liquid/solid fluidization phenomena were investigated to determine the processes that are responsible for freeze-up of the ice slurry generator. Also the thermophysical properties of the ice slurries and their behavior in secondary cooling cycles were evaluated. The results were implemented in a dynamic simulation model in which the economic and energetic performance of the fluidized bed ice slurry generator could be evaluated in detail. It was shown that the novel technique may be a competitive option even in air-conditioning applications in the Netherlands.Mechanical Maritime and Materials Engineerin
Modelling of cooled-ceiling air-conditioning systems: Influences on indoor environment and energy consumption
No full textMechanical Maritime and Materials Engineerin
Development of wet compressor for application in compression-resorption heat pumps
No full textMechanical Maritime and Materials Engineerin
Bad roads, good roads
No full textRoads greatly influence the footprint of human activity, but they are often constructed with little consideration of their environmental impacts, especially in developing nations. Here, differences between environmentally 'good' and 'bad' roads are highlighted, and it is argued that a proactive road‐zoning system is direly needed at international and national scales. Such a zoning system could identify areas where the environmental costs of roads are likely to be high and their socioeconomic benefits low, as well as areas where road improvements could have modest environmental costs and large societal benefits.
2.1 Land‐use pressures will rise sharply this century and will be strongly influenced by roads.
2.2 Agricultural yield increases alone will not spare nature – land‐use zoning is crucial too.
2.3 Roads in pristine areas are environmentally dangerous – the first cut is critical.
2.4 Paved highways have especially large‐scale impacts.
2.5 Roads can be environmentally beneficial in certain contexts.
2.6 Roads are amenable to policy modification.
2.7 A recently proposed global road‐mapping scheme could serve as a potential model for these efforts.
This road‐planning scheme could be an important tool for prioritising road investments and for underscoring the transformative role of roads in determining environmental change. An overriding priority is to proactively zone roads at a range of spatial scales while highlighting their critical role in provoking environmental change. Keeping roads out of surviving irreplaceable natural areas is among the most tractable and cost‐effective ways to protect crucial ecosystems and the vital services they provide, whereas roads in the right places can facilitate increases in agricultural productivity and efficiency
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