A multicriteria decision support model and geographic information system for systainable development planning of the Greek islands

This presents an evaluation of various scenarios for sustainable development on the Greek island of Alonnisos using the new information technology of geographic information systems (GIS). The most desirable development option was very clear after the analysis, but any policy choice must take into account the various actors involved and their conflicting interests. At best the GIS-based decision support system tools may increase awareness of current frictions and future incompatibilities in economic development, environmental sustainability and land-use shifts

Concrete shell structures revisited : introducing a new and 'low-tech' construction method using vacuumatics formwork

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Segmented Barrel-Vaulted Glass Roof

A structural system for segmented barrel-vaulted glass roofs has been developed,aiming at maximum transparency due to structural optimization. This has led to astructural system with small connections, integrated into the glass, as well as clear,transparent joints. Finite element analysis and a full-scale test has been performed,showing PVB-laminated glass, 101010.4, could be sufficient to create spans up to20 meters with slightly prestressed cables measuring just 3 mm in diameter

Discrete Element Modelling of VACUUMATICS

Vacuumatics consist of independent particles inside an airtight enclosed membrane, that are prestressed due to a difference in (air) pressure. Analytical and numerical research of vacuum prestressing has illustrated that the effective prestressing forces can be divided into two interrelated prestressing components. Due to the granular characteristics of Vacuumatics, the material behaviour can be modelled by means of the Discrete Element Method (DEM). The individual prestressing components acting on the edge particles of vacuumatic structures can be simulated by means of a specialised Atmospheric Pressure Model in HADES (by Habanera). Analytically defined equations form the basic input in this simulation process. These simulations enable us to analyse (visually as well as numerically) the prestressing forces, but also the contact forces and the displacements of each particle due to this vacuum prestressing. Furthermore, bending phenomena of beam-shaped Vacuumatics can be analysed in detail, providing us with insight to describe and predict the structural properties of any type of vacuumatic structure

VACUUMATICS; Systematic Flexural Rigidity Analysis

The structural integrity of vacuumatics relies on the principle of prestressing unbound particles inside an enclosed membrane. By introducing a negative pressure (partial vacuum) inside this airtight flexible enclosure, the membrane is tightly wrapped around the outer particles, hence effectively bonding the particle filling to create (adaptable) load-bearing structures. Analytical and numerical studies on the fundamental prestress derivation of vacuumatically prestressed structures have shown that the effective prestressing forces between the particles largely depend, apart from the differential in (air) pressure differential, on the elastic properties of the skin material. The flexural rigidity of vacuumatics is mainly determined by the material properties of the particles and membrane used. Variations in elasticity of the skin and particle filling, and with this the shape, size, compressiveness, roughness, and packing density of the individual particles, highly influence the structural behaviour of vacuumatic structures. In order to explore the influence of different particle and skin characteristics (or parameters) on the flexural rigidity, experimental research has been carried out by means of four point bending tests. Different types of particles were used to discover behavioural trends dependent on the parameters varied. The results of this study provide an enhanced understanding of the true overall structural response of vacuumatics. By systematically elaborating the different parameters, we are able to determine what specific material properties are desired to design the ‘most efficient’ vacuumatic structure for every application

Map-based multicriteria analysis to support interactive land use allocation

This article focuses on the use of map-based multicriteria analysis to develop a negotiation support tool for land use allocation. Spatial multicriteria analysis is used to make explicit trade-offs between objectives and to provide guidance and feedback on the land use changes negotiated by the participants. Digital maps are the means of communication among workshop participants, and an interactive mapping device (the 'Touch table') is used as the interface. Participants are informed about the relevant trade-offs on the map and use this information to change the land use maps. The approach is tested during a negotiation session as part of the land use planning process of the Bodegraven polder, a peat meadow area in the Netherlands. © 2011 Copyright Taylor and Francis Group, LLC

Gag- and env-specific serum antibodies in cats after natural and experimental infection with feline immunodeficiency virus.

In order to monitor the antibody response to feline immunodeficiency virus (FIV) in cats, following experimental and natural infection, enzyme-linked immunosorbent assays (ELISAs) were developed using recombinant env and gag proteins and p24-specific monoclonal antibodies. It was shown that in experimentally infected cats an env protein-specific antibody response was directly followed by a gag protein-specific response. Furthermore, an ELISA for the detection of env protein-specific serum antibodies proved more sensitive in identifying experimentally and naturally infected cats than ELISAs demonstrating gag protein-specific antibodies. It was concluded that, like in HIV infection of humans, the detection of env protein-specific serum antibodies in addition to gag protein-specific antibodies is not only an important tool in the diagnosis of the infection but also in studies concerning the pathogenesis of the disease