Dynamic Decals

Pervasive interfaces can present relevant information anywhere in our environment, and they are thus challenged by the non rectilinearity of the display surface (e.g. circular table) and by the presence of objects that can partially occlude the interface (e.g. a book or cup on the table). To tackle this problem, we propose a novel solution based on two core contributions: the decomposition of the interface into deformable graphical units, called Dynamic Decals, and the control of their position and behaviour by a constraint-based approach. Our approach dynamically deforms the interface when needed while minimizing the impact on its visibility and layout properties. To do so, we extend previous work on implicit deformations to propose and experimentally validate functions defining different decal shapes and new deformers modeling decal deformations when they collide. Then, we interactively optimize the decal placements according to the interface geometry and their interrelations. Relations are modeled as constraints and the interface evolution results from an easy and efficient to solve minimization problem. Our approach is validated by a user study showing that, compared to two baselines, Dynamic decals is an aesthetically pleasant interface that preserves visibility, layout and aesthetic properties.

Effect of Interface Geometry on Strength of Single Lap Adhesive Joint of Sisal-Glass/Epoxy Laminates

In this project, experimental work on tensile behaviour of single lap adhesive joints of sisal, glass and hybrid sisal-glass/epoxy composite laminates has been carried out. Composite laminates were fabricated by hand lay-up method using chopped strand mat sisal and glass fibers with epoxy resin matrix. Lab joints of four interface geometries; straight flat, triangular, rectangular and sinusoidal were fabricated. Tensile load-displacement relations were drawn and discussed. Effect of interface geometry and material type on maximum load and strength of the single lap joint was investigated. Failure mechanism of the fractured specimens was discussed. Results show that the glass/epoxy lap joints with semi-circular adhesive interface geometry supported load higher respectively 14.26%, 26.13%, and 30.79% than rectangular, triangular and straight flat interface geometries. Glass/epoxy lap joint with semi-circular interface geometry supported tensile load higher 5.61% and 21.83% than that obtained from hybrid sisal-glass and sisal/ epoxy adhesive joints. While the shear strength was found higher respectively 6.19% and 18.69%. Adhesive failure mode was observed for most of the single lap joints investigated. Mixed failure mode of adhesive and adherend materials was observed on the sisal/epoxy lap joints.

Reformulation of Parker–Oldenburg's method for Earth's spherical approximation

SUMMARY Parker–Oldenburg's method is perhaps the most commonly used technique to estimate the depth of density interface from gravity data. To account for large density variations reported, for instance, at the Moho interface, between the ocean seawater density and marine sediments, or between sediments and the underlying bedrock, some authors extended this method for variable density models. Parker–Oldenburg's method is suitable for local studies, given that a functional relationship between gravity data and interface geometry is derived for Earth's planar approximation. The application of this method in (large-scale) regional, continental or global studies is, however, practically restricted by errors due to disregarding Earth's sphericity. Parker–Oldenburg's method was, therefore, reformulated also for Earth's spherical approximation, but assuming only a uniform density. The importance of taking into consideration density heterogeneities at the interface becomes even more relevant in the context of (large-scale) regional or global studies. To address this issue, we generalize Parker–Oldenburg's method (defined for a spherical coordinate system) for the depth of heterogeneous density interface. Furthermore, we extend our definitions for gravity gradient data of which use in geoscience applications increased considerably, especially after launching the Gravity field and steady-state Ocean Circulation Explorer (GOCE) gravity-gradiometry satellite mission. For completeness, we also provide expressions for potential. The study provides the most complete review of Parker–Oldenburg's method in planar and spherical cases defined for potential, gravity and gravity gradient, while incorporating either uniform or heterogeneous density model at the interface. To improve a numerical efficiency of gravimetric forward modelling and inversion, described in terms of spherical harmonics of Earth's gravity field and interface geometry, we use the fast Fourier transform technique for spherical harmonic analysis and synthesis. The (newly derived) functional models are tested numerically. Our results over a (large-scale) regional study area confirm that the consideration of a global integration and Earth's sphericty improves results of a gravimetric forward modelling and inversion.

Correcting for physical distortions in visual stimuli improves reproducibility in zebrafish neuroscience

Optical refraction causes light to bend at interfaces between optical media. This phenomenon can significantly distort visual stimuli presented to aquatic animals in water, yet refraction has often been ignored in the design and interpretation of visual neuroscience experiments. Here we provide a computational tool that transforms between projected and received stimuli in order to detect and control these distortions. The tool considers the most commonly encountered interface geometry, and we show that this and other common configurations produce stereotyped distortions. By correcting these distortions, we reduced discrepancies in the literature concerning stimuli that evoke escape behavior, and we expect this tool will help reconcile other confusing aspects of the literature. This tool also aids experimental design, and we illustrate the dangers that uncorrected stimuli pose to receptive field mapping experiments.

ON THE PROBLEM OF STRAIN LOCALIZATION AND FRACTURE SITE PREDICTION IN MATERIALS WITH IRREGULAR GEOMETRY OF INTERFACES

The interfacial mechanisms of the stress-strain localization in non-homogeneous media are investigated, using a steel substrate - iron boride coating composition subjected to tension as an example. A dynamic boundary-value problem in a plane-strain formulation is solved numerically by the finite-difference method. The curvilinear substrate-coating interface geometry is assigned explicitly in calculations and is in agreement with experiment. Constitutive relations accounting for an elastic-plastic response of the isotropically-hardened substrate and for a brittle fracture of the coating are employed. Three stages of the plastic strain localization in the steel substrate are found to occur due to the irregular interface geometry. Distributions of the stress concentration regions in the coating are shown to be different at different stages. The stress concentration in the coating is demonstrated to increase nonlinearly during the third stage. The location of fracture is found to depend on the strength of the coating.

Cytoskeletal tension and Bazooka tune interface geometry to ensure fusion fidelity and sheet integrity during dorsal closure

Epithelial fusion establishes continuity between the separated flanks of epithelial sheets. Despite its importance in creating resilient barriers, the mechanisms that ensure stable continuity and preserve morphological and molecular symmetry upon fusion remain unclear. Using the segmented embryonic epidermis whose flanks fuse during Drosophila dorsal closure, we demonstrate that epidermal flanks modulate cell numbers and geometry of their fusing fronts to achieve fusion fidelity. While fusing flanks become more matched for both parameters before fusion, differences persisting at fusion are corrected by modulating fusing front width within each segment to ensure alignment of segment boundaries. We show that fusing cell interfaces are remodelled from en-face contacts at fusion to an interlocking arrangement after fusion, and demonstrate that changes in interface length and geometry are dependent on the spatiotemporal regulation of cytoskeletal tension and Bazooka/Par3. Our work uncovers genetically constrained and mechanically triggered adaptive mechanisms contributing to fusion fidelity and epithelial continuity.