1,014 research outputs found

    SWAP Version 3.2. Theory description and user manual

    Get PDF
    SWAP 3.2 simulates transport of water, solutes and heat in the vadose zone. It describes a domain from the top of canopy into the groundwater which may be in interaction with a surface water system. The program has been developed by Alterra and Wageningen University, and is designed to simulate transport processes at field scale and during whole growing seasons. This is a new release with special emphasis on numerical stability, macro pore flow, and options for detailed meteorological input and linkage to other models. This manual describes the theoretical background, model use, input requirements and output tables

    The Critical Aggregation Concentration of ß-Lactoglobulin-Based Fibril Formation

    Get PDF
    The critical aggregation concentration (CAC) for fibril formation of ß-lactoglobulin (ß-lg) at pH 2 was determined at 343, 353, 358, 363, and 383 K using a Thioflavin T assay and was approximately 0.16 wt%. The accuracy of the CAC was increased by measuring the conversion into fibrils at different stirring speeds. The corresponding binding energy per mol, as determined from the CAC, was 13 RT (~40 kJ mol¿1) for the measured temperature range. The fact that the CAC was independent of temperature within the experimental error indicates that the fibril formation of ß-lg at pH 2 and the measured temperature range is an entropy-driven process

    Modelling the role of the design context in the design process: a domain-independent approach

    Get PDF
    Domain-independent models of the design process are an important means for facilitating interdisciplinary communication and for supporting multidisciplinary design. Many so-called domain-independent models are, however, not really domain independent. We state that, to be domain independent, the models must abstract from domain-specific aspects, be based on the study of several design disciplines, and be useful for many design disciplines and for multidisciplinary design teams. This paper describes a domain-independent descriptive design model that is developed by studying similarities and differences between design processes in a few design disciplines. The model is based on the general theory of state transitions. We modelled a design situation as a state at a certain moment and a design activity as a transition. We also explicitly modelled the role of the design context in design processes. In our empirical studies, we noticed the influence of the design context on the product being designed and the design process and the importance of communication between designers and stakeholders in the design context regularly during the design process. Making designers aware of the role of the design context can improve the quality of both the product being designed and the design process. The role of the design context is, however, often not explicitly taken into account in design models. We modelled the design context as part of the state at a certain moment and interaction with the design context as one of the activities performed by designers

    Exposure Render: An Interactive Photo-Realistic Volume Rendering Framework

    Get PDF
    The field of volume visualization has undergone rapid development during the past years, both due to advances in suitable computing hardware and due to the increasing availability of large volume datasets. Recent work has focused on increasing the visual realism in Direct Volume Rendering (DVR) by integrating a number of visually plausible but often effect-specific rendering techniques, for instance modeling of light occlusion and depth of field. Besides yielding more attractive renderings, especially the more realistic lighting has a positive effect on perceptual tasks. Although these new rendering techniques yield impressive results, they exhibit limitations in terms of their exibility and their performance. Monte Carlo ray tracing (MCRT), coupled with physically based light transport, is the de-facto standard for synthesizing highly realistic images in the graphics domain, although usually not from volumetric data. Due to the stochastic sampling of MCRT algorithms, numerous effects can be achieved in a relatively straight-forward fashion. For this reason, we have developed a practical framework that applies MCRT techniques also to direct volume rendering (DVR). With this work, we demonstrate that a host of realistic effects, including physically based lighting, can be simulated in a generic and flexible fashion, leading to interactive DVR with improved realism. In the hope that this improved approach to DVR will see more use in practice, we have made available our framework under a permissive open source license

    Аграрне перенаселення в українських губерніях Російської імперії початку ХХ ст.

    Get PDF
    Sustainable urban development is a critical issue in the Netherlands. The country is densely populated, which causes conflicts between environmental concerns and spatial development. Environmental policy integration is proposed as a way to improve the integration of environmental values into spatial planning with the help of learning processes. This chapter evaluates the extent to which the combination of a map-based touch table and an area-specific environmental profile are of added value to environmental policy integration. The case study is the application of the map-based touch table, called MapTable® for the development of a sustainable neighborhood in the region of Utrecht, the Netherlands. It was found that MapTable® facilitates learning processes by providing a platform for communication among stakeholders from different backgrounds. Nonetheless, it must be ensured that all stakeholders are equally included, and that the process suits the application of a map-based touch table in combination with an area-specific environmental profile

    Towards a Conceptualization of Sociomaterial Entanglement

    Get PDF
    In knowledge representation, socio-technical systems can be modeled as multiagent systems in which the local knowledge of each individual agent can be seen as a context. In this paper we propose formal ontologies as a means to describe the assumptions driving the construction of contexts as local theories and to enable interoperability among them. In particular, we present two alternative conceptualizations of the notion of sociomateriality (and entanglement), which is central in the recent debates on socio-technical systems in the social sciences, namely critical and agential realism. We thus start by providing a model of entanglement according to the critical realist view, representing it as a property of objects that are essentially dependent on different modules of an already given ontology. We refine then our treatment by proposing a taxonomy of sociomaterial entanglements that distinguishes between ontological and epistemological entanglement. In the final section, we discuss the second perspective, which is more challenging form the point of view of knowledge representation, and we show that the very distinction of information into modules can be at least in principle built out of the assumption of an entangled reality

    Forces on a boiling bubble in a developing boundary layer, in microgravity with g-jitter and in terrestrial conditions

    Get PDF
    Terrestrial and microgravity flow boiling experiments were carried out with the same test rig, comprising a locally heated artificial cavity in the center of a channel near the frontal edge of an intrusive glass bubble generator. Bubble shapes were in microgravity generally not far from those of truncated spheres,which permitted the computation of inertial lift and drag from potential flow theory for truncated spheres approximating the actual shape. For these bubbles, inertial lift is counteracted by drag and both forces are of the same order of magnitude as g-jitter. A generalization of the Laplace equation is found which applies to a deforming bubble attached to a plane wall and yields the pressure difference between the hydrostatic pressures in the bubble and at the wall, p. A fully independent way to determine the overpressure p is given by a second Euler-Lagrange equation. Relative differences have been found to be about 5% for both terrestrial and microgravity bubbles. A way is found to determine the sum of the two counteracting major force contributions on a bubble in the direction normal to the wall from a single directly measurable quantity. Good agreement with expectation values for terrestrial bubbles was obtained with the difference in radii of curvature averaged over the liquid-vapor interface, (1/R2 − 1/R1), multiplied with the surface tension coefficient, σ. The new analysis methods of force components presented also permit the accounting for a surface tension gradient along the liquid-vapor interface. No such gradients were found for the present measurements
    corecore