Mass Transfer and Friction in Near-Wall Film Flows in Conditions of High-Velocity Co-Current Gas Flow

We present the experimental research on the interaction of co-current gas flow with near-wall liquid film for gas velocities up to 300 m/s. Local parameters of near-wall liquid film are measured by using capacity-type probes. It is shown that co-current gas flow has strong influence on near-wall liquid film, leading to intensive wave formation, detachment of droplets from the film surface and their entrainment by the gas flow. Thus it is shown that the relative amount of liquid carried away by co-current gas flow is well characterized by Weber number of gas flow. A model for the motion of a film with co-current flow, connecting a thickness and velocity of the film with value of shearing stress at gas-liquid boundary, is suggested. It is shown that intensive wave formation leads to essential increase of the interphase friction value.     

Translating visual art into tactile art to produce equivalent aesthetic experiences.

An argument is put forward to show that visual art may actually be translated into tactile objects that produce equivalent aesthetic experiences for blind or visually impaired people. This is shown by delineating the information required for such a translation in general, demonstrating that such a translation is already achievable from color vision to color vision and theoretically possible from spatial vision to spatial touch, and outlining that an analogous procedure could be applied to aesthetic experience. Limitations of such translations of visual works of art into tactile objects, and implications of such a procedure for artistic experience and education, are also mentioned. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Local Minima and Gradients of Stiffness and Conductivity as Indicators of Strength Reduction of Brittle-Elastic Materials

It is often suggested in literature to use change in the effective elastic properties (stiffness loss) as an indicator of reduction of strength due to defects such as cracks and pores. We argue that the key parameter is not the reduction of the average (over the specimen) stiffness but its local minimal values caused by formation of defect clusters. These defect clusters can be identified by the emergence of spatial gradients of elastic stiffness on a smaller scale. A convenient tool of detecting these gradients is provided by the elasticity-conductivity connection: the electric conductance gradient is usually easier to measure than the stiffness gradient. This concept is supported by computational and experimental results reported in two accompanying papers published in the present issue (by Sevostianov et al and Caiulo and Kachanov).     

Scalable approach to uncertainty quantification and robust design of interconnected dynamical systems

Development of robust dynamical systems and networks such as autonomous aircraft systems capable of accomplishing complex missions faces challenges due to the dynamically evolving uncertainties coming from model uncertainties, necessity to operate in a hostile cluttered urban environment, and the distributed and dynamic nature of the communication and computation resources. Model-based robust design is difficult because of the complexity of the hybrid dynamic models including continuous vehicle dynamics, the discrete models of computations and communications, and the size of the problem. We will overview recent advances in methodology and tools to model, analyze, and design robust autonomous aerospace systems operating in uncertain environment, with stress on efficient uncertainty quantification and robust design using the case studies of the mission including model-based target tracking and search, and trajectory planning in uncertain urban environment. To show that the methodology is generally applicable to uncertain dynamical systems, we will also show examples of application of the new methods to efficient uncertainty quantification of energy usage in buildings, and stability assessment of interconnected power networks.     

Experimental Study of Film Condensation of FC-72 Vapour on Disk-Shaped Fin

The results of activity made in the framework of preparation of the experiment SAFIR (Single fin condensAtion: FIlm local measuRements) of European Space Agency are presented. First prototype of the test cell has been developed and tested. Confocal technique has been adopted for condensate film thickness measurements. Experiments on condensation of the liquid FC-72 have been carried out. Average heat transfer coefficient has been measured in the range of 880–1440 W/m² K and compared to the Nusselt theory.     

Experimental Study of Laminar Convective Condensation of Pure Vapor Inside an Inclined Circular Tube

Convective condensation of pure ethanol vapor inside a smooth tube of inner diameter 4.8 mm and of length 200 mm is studied. The experiments have been carried out at temperature 58°C corresponding to the pressure of 440 mbar, the vapor mass velocity varying from 0.24 to 2.04 kg/(m² s). The dependency of the Heat Transfer Coefficient (HTC) is investigated experimentally both subject to the temperature difference between the saturated vapor and the wall and subject to the condenser inclination. The results show that the HTC reduces with growth of the temperature difference. The dependency of the HTC on inclination has a maximum in the range 15°–35° due to the complex gravity drainage mechanism of the condensed liquid. The results could be useful for development of compact effective cooling systems for space and ground application.     

Energy demand in the Norwegian building stock: Scenarios on potential reduction

A model has been developed for studying the effect of three hypothetical approaches in reducing electricity and energy demand in the Norwegian building stock: wide diffusion of thermal carriers, heat pumps and conservation measures, respectively. Combinations of these are also considered. The model has a demand side perspective, considers both residential and service sectors, and calculates energy flows from net to delivered energy. Energy demand is given by the product of activity and intensity matrices. The activity levels are defined for the stock and the new construction, renovation and demolition flows. The intensity properties are defined in archetypes, and are the result of different energy class and heating carriers share options. The scenarios are shaped by combining the activity flows with different archetypes. The results show that adopting conservation measures on a large scale does allow reducing both electricity and total energy demand from present day levels while the building stock keeps growing. The results also highlight the importance of making a clear distinction between the assumptions on intensity and activity levels.     

Experimental observation of speckle instability in a two-dimensional disordered medium

Temporal fluctuations of the speckle pattern formed upon backscattering of a laser beam from an interface between gold and nonlinear polymer film have been observed as a function of optical power. The instability can be explained by coupling of laser light to surface plasmons and other guided modes, which experience multiple scattering while propagating in the film along the interface. The speckle pattern produced in this process is extremely sensitive to fluctuations of the scattering potential near the interface.     

Semantic Mediation for Standard-Based B2B Interoperability

The authors discuss a semantic-mediation architecture to advance traditional approaches for standards-based business-to-business (B2B) interoperability. The architecture is supported by the Athena Knowledge Representation and Semantics Mediation tool suite. Initial experimentations with the architecture and the toolset offer discussions of key architectural and functional aspects and suggest directions for future tools enhancements.