Delft University of Technology

About: Delft University of Technology is a education organization based out in Delft, Zuid-Holland, Netherlands. It is known for research contribution in the topics: Computer science & Catalysis. The organization has 37681 authors who have published 94404 publications receiving 2741710 citations. The organization is also known as: TU-Delft & Technische Hogeschool Delft.

Solar air conditioning in Europe—an overview

Abstract: Summer air conditioning represents a growing market in buildings worldwide, with a particularly significant growth rate observed in European commercial and residential buildings. Heat-driven cooling technologies are available, which can be used in combination with solar thermal collectors to alleviate the burden caused by air conditioning on the electric utilities and the environment. Solar air conditioning has progressed considerably over the past years as a result of efforts toward environmental protection and new developments in components and systems, and significant experience has been gained from demonstration projects. The main obstacles for large scale application, beside the high first cost, are the lack of practical experience and acquaintance among architects, builders and planners with the design, control and operation of these systems. This paper describes the main results of the EU project SACE (Solar Air Conditioning in Europe), aimed to assess the state-of-the-art, future needs and overall prospects of solar cooling in Europe. A group of researchers from five countries has surveyed and analyzed over 50 solar-powered cooling projects in different climatic zones. The paper presents a short overview on the state-of-the-art and potential of solar-assisted cooling and air conditioning technologies. The results of the study, including a database of the surveyed projects, an evaluation of these projects on a uniform basis, an economic analysis tool, user guidelines and a multimedia tool—are presented. The potential energy savings and limitations of solar thermal air conditioning in comparison to conventional technologies are illustrated and discussed.

The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

Abstract: There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost effective at greater depths. Nature-based defence projects also report benefits ranging from reductions in storm damage to reductions in coastal structure costs.

The State of the Art in Flow Visualization : Dense and Texture-Based Techniques

Abstract: Flow visualization has been a very attractive component of scientific visualization research for a long time. Usually very large multivariate datasets require processing. These datasets often consist of a large number of sample locations and several time steps. The steadily increasing performance of computers has recently become a driving factor for a reemergence in flow visualization research, especially in texture-based techniques. In this paper, dense, texture-based flow visualization techniques are discussed. This class of techniques attempts to provide a complete, dense representation of the flow field with high spatio-temporal coherency. An attempt of categorizing closely related solutions is incorporated and presented. Fundamentals are shortly addressed as well as advantages and disadvantages of the methods.

The glass transition as a free volume related kinetic phenomenon

Abstract: The glass transition, observed in glasses during DSC experiments at a constant heating rate, is described as a kinetic phenomenon caused by the continuous approach of free volume towards equilibrium during the warming up. At a certain temperature below the glass temperature T g , the amount of free volume becomes smaller than the equilibrium value at that temperature. The glass transition is caused by a rather sudden increase of free volume towards equilibrium near T g . This can be calculated by making use of the well known kinetics of free volume annilation and production in some metallic glasses. Calculations performed on this basis are in good agreement with available experimental data, both on structural relaxation and the glass transition.

Cross-linked enzyme aggregates (CLEAs): stable and recyclable biocatalysts.

Abstract: The key to obtaining an optimum performance of an enzyme is often a question of devising an effective method for its immobilization. In the present review, we describe a novel, versatile and effective methodology for enzyme immobilization as CLEAs (cross-linked enzyme aggregates). The method is exquisitely simple (involving precipitation of the enzyme from aqueous buffer followed by cross-linking of the resulting physical aggregates of enzyme molecules) and amenable to rapid optimization. We have shown it to be applicable to a wide variety of enzymes, including, in addition to a wide variety of hydrolases, lyases, e.g. nitrile hydratases and oxynitrilases, and oxidoreductases such as laccase and galactose oxidase. CLEAs are stable, recyclable catalysts exhibiting high catalyst productivities. Because the methodology is essentially a combination of purification and immobilization into one step, the enzyme does not need to be of high purity. The technique is also applicable to the preparation of combi-CLEAs, containing two or more enzymes, for use in one-pot, multistep syntheses, e.g. an oxynitrilase/nitrilase combi-CLEA for the one-pot conversion of benzaldehyde into (S)-mandelic acid, in high yield and enantiomeric purity.