Cosimulation of Electromagnetics-Circuit Systems Exploiting DGTD and MNA

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A Resistive Boundary Condition Enhanced DGTD Scheme for the Transient Analysis of Graphene

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A hybrid time-domain discontinuous Galerkin-boundary integral method for 3-D electromagnetic scattering analysis

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Sustainable manufacturing of new construction material from alkali activation of volcanic tuff

The current climate emergency leads to reduction of virgin raw material extraction and promotes circular economy. In this framework, alkali activation of unemployed fraction of grey tuff, combined with glass waste, provides a range of sustainable construction materials. For the sake of sustainability, tuff powder was subjected to rapid attack (30 min), operated by a 'weak' alkaline solution (3 M NaOH), and then left to dry at low temperature (75 degrees C) for 72 h. The addition of Triton X-100 surfactant was considered to obtain foams starting from slurries with different liquid-to-solid ratio. A thermal treatment was applied to selected samples, at low temperature (700 degrees C). Despite the 'mild' activation conditions, all products survived after immersion in boiling water or acid solution, already in the unfired state, according to the formation of a multiphasic gel. The strength-to density ratio, especially for foams, in both unfired and fired form, compares well with that of already existing construction materials (e.g. it could exceed 5 MPa cm3/g)

How Do You Like Me in This: User Embodiment Preferences for Companion Agents

We investigate the relationship between the embodiment of an artificial companion and user perception and interaction with it. In a Wizard of Oz study, 42 users interacted with one of two embodiments: a physical robot or a virtual agent on a screen through a role-play of secretarial tasks in an office, with the companion providing essential assistance. Findings showed that participants in both condition groups when given the choice would prefer to interact with the robot companion, mainly for its greater physical or social presence. Subjects also found the robot less annoying and talked to it more naturally. However, this preference for the robotic embodiment is not reflected in the users’ actual rating of the companion or their interaction with it. We reflect on this contradiction and conclude that in a task-based context a user focuses much more on a companion’s behaviour than its embodiment. This underlines the feasibility of our efforts in creating companions that migrate between embodiments while maintaining a consistent identity from the user’s point of view

Casimir force between surfaces close to each other

Casimir interactions (due to the massless scalar field fluctuations) of two surfaces which are close to each other are studied. After a brief general presentation, explicit calculations for co-axial cylinders, co-centric spheres and co-axial cones are performed.Comment: Latex, 20 pages, added references, corrected typos, changed conten

On the Low-Frequency Behavior of Vector Potential Integral Equations for Perfect Electrically Conducting Scatterers

Low-frequency behavior of vector potential integral equations (VPIEs) for perfect electrically conducting scatterers is investigated. Two equation sets are considered: The first set (VPIE-1) enforces the tangential component of the vector potential on the scatterer surface to be zero and uses the fundamental field relation on its normal component. The second set (VPIE-2) uses the same condition as VPIE-1 for the tangential component of the vector potential but enforces its divergence to be zero. In both sets, unknowns are the electric current and the normal component of the vector potential on the scatterer surface and are expanded using Rao-Wilton-Glisson (RWG) and pulse basis functions, respectively. To achieve a conforming discretization, RWG, scalar Buffa-Christiansen, and pulse testing functions are used. Theoretical and numerical analyses of the resulting matrix systems show that the electric current obtained by solving VPIE-1 has the wrong frequency scaling and is inaccurate at low frequencies