Accelerating Scientific Discovery Through Computation and Visualization

The rate of scientific discovery can be accelerated through computation and visualization. This acceleration results from the synergy of expertise, computing tools, and hardware for enabling high-performance computation, information science, and visualization that is provided by a team of computation and visualization scientists collaborating in a peer-to-peer effort with the research scientists.In the context of this discussion, high performance refers to capabilities beyond the current state of the art in desktop computing. To be effective in this arena, a team comprising a critical mass of talent, parallel computing techniques, visualization algorithms, advanced visualization hardware, and a recurring investment is required to stay beyond the desktop capabilities.This article describes, through examples, how the Scientific Applications and Visualization Group (SAVG) at NIST has utilized high performance parallel computing and visualization to accelerate condensate modeling, (2) fluid flow in porous materials and in other complex geometries, (3) flows in suspensions, (4) x-ray absorption, (5) dielectric breakdown modeling, and (6) dendritic growth in alloys.     

Diffusion in partially-saturated porous materials

The diffusive transport of ions in two classes of porous media was studied as a function of fluid saturation and wetting properties. A lattice Boltzmann method was used to model phase separation of a binary mixture, including wetting effects, in porous media. Diffusive transport is then evaluated in each separate phase. It is found that the degree of saturation of each phase can strongly affect the transport of ions that are limited to diffusing in either the wetting or non-wetting phase. At high saturations, good agreement is found between our estimates of diffusivity and that predicted by the semi-empirical Archie's second law. At lower saturations it is found that Archie's second law breaks down as percolation effects become important.

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Résumé Le transport d'ions par diffusion dans deux milieux poreux différents est étudié en fonction de leurs saturation en fluide et mouillabilité. Un maillage selon la méthode de Boltzmann est utilisé pour modéliser la séparation de phase du mélange binaire constituant le milieu poreux. Le modèle prend en compte les effets de mouillabilité. Le transport par diffusion est ensuite évalué dans chaque phase. Il est observé que le degré de saturation de chaque phase peut grandement affecter le transport des ions pour lesquels la diffusion est limitée à la phase mouillable ou à la phase non mouillable. Aux fortes saturations, nos estimations concernant la diffusivité sont en accord avec celles prévues par la seconde loi d'Archie laquelle est semi-empirique. Aux faibles saturations, la seconde loi d'Archie n'est plus valable lorsque les effets de percolation deviennent importants.

     

MINIATURE LANDSCAPES

This visual essay examines Sharqi, a collection of 27 polaroid photographs that are the result of Nicos Philippou’s decade-long photographic and theoretical investigation of Cypriot topography. The essay explores the ways in which Sharqi challenges existing photographic representations of Cyprus, produced mainly in the early-to-mid twentieth century by photographers, by travellers and by the state itself, while raising relevant questions about how: (a) Cypriot landscape photography often carries a romanticized and orientalizing gaze that attests as much to the island’s specific colonial past as to photography’s ties to imperialism, and (b) photography has often become a vehicle for perpetuating a Greek-Cypriot nationalism on the island. Finally, the essay addresses the documentary, autobiographical and self-referential nature of polaroid photography by discussing specific photographs from the Sharqi series. This article also looks at Sharqi in relation to relevant historic examples from the work of Ed Ruscha and Walker Evans.     

Remotely Sensed Methodologies for Crop Water Availability and Requirements in Precision Farming of Vulnerable Agriculture

Water Resources Management - Agriculture is mainly impacted by water availability. Differences in climate conditions and the appearance of severe events, like droughts, has a significant imprint on...     

Relating Fresh Concrete Viscosity Measurements from Different Rheometers

Concrete rheological properties need to be properly measured and predicted in order to characterize the workability of fresh concrete, including special concretes such as self-consolidating concrete (SCC). It was shown by a round-robin test held in 2000 [1,2] that different rheometer designs gave different values of viscosity for the same concrete. While empirical correlation between different rheometers was possible, for a procedure that is supposed to “scientifically” improve on the empirical slump tests, this situation is unsatisfactory. To remedy this situation, a new interpretation of the data was developed. In this paper, it is shown that all instruments tested could be directly and quantitatively compared in terms of relative plastic viscosity instead of the plastic viscosity alone. This should eventually allow the measurements from various rheometer designs to be directly calibrated against known standards of plastic viscosity, putting concrete rheometry and concrete workability on a sounder materials science basis.     

A multiagent system enhancing home-care health services for chronic disease management.

In this paper, a multiagent system (MAS) is presented, aiming to enhance monitoring, surveillance, and educational services of a generic medical contact center (MCC) for chronic disease management. In such a home-care scenario, a persistent need arises for efficiently monitoring the patient contacts and the MCC's functionality, in order to effectively manage and interpret the large volume of medical data collected during the patient sessions with the system, and to assess the use of MCC resources. Software agents were adopted to provide the means to accomplish such real-time information-processing tasks, due to their autonomous, reactive and/or proactive nature, and their effectiveness in dynamic environments by incorporating coordination strategies. Specifically, the objective of the MAS is to monitor the MCC environment, detect important cases, and inform the healthcare and administrative personnel via alert messages, notifications, recommendations, and reports, prompting them for actions. The main aim of this paper is to present the overall design and implementation of a proposed MAS, emphasizing its functional model and architecture, as well as on the agent interactions and the knowledge-sharing mechanism incorporated, in the context of a generic MCC.