Advances in shape-morphing materials, such as hydrogels, shape-memory polymers and light-responsive polymers have enabled prescribing self-directed deformations of initially flat geometries. However, most proposed solutions evolve towards a target geometry without considering time-dependent actuation paths. To achieve more complex geometries and avoid self-collisions, it is critical to encode a spatial and temporal shape evolution within the initially flat shell. Recent realizations of time-dependent morphing are limited to the actuation of few, discrete hinges and cannot form doubly curved surfaces. Here, we demonstrate a method for encoding temporal shape evolution in architected shells that assume complex shapes and doubly curved geometries. The shells are non-periodic tessellations of pre-stressed contractile unit cells that soften in water at rates prescribed locally by mesostructure geometry. The ensuing midplane contraction is coupled to the formation of encoded curvatures. We propose an inverse design tool based on a data-driven model for unit cells' temporal responses.

We present a computational approach for designing CurveUps, curvy shells that form from an initially flat state. They consist of small rigid tiles that are tightly held together by two pre-stretched elastic sheets attached to them. Our method allows the realization of smooth, doubly curved surfaces that can be fabricated as a flat piece. Once released, the restoring forces of the pre-stretched sheets support the object to take shape in 3D. CurveUps are structurally stable in their target configuration. The design process starts with a target surface. Our method generates a tile layout in 2D and optimizes the distribution, shape, and attachment areas of the tiles to obtain a configuration that is fabricable and in which the curved up state closely matches the target. Our approach is based on an efficient approximate model and a local optimization strategy for an otherwise intractable nonlinear optimization problem. We demonstrate the effectiveness of our approach for a wide range of shapes, all realized as physical prototypes.

Cold bent glass is a promising and cost-efficient method for realizing doubly curved glass façades. They are produced by attaching planar glass sheets to curved frames and must keep the occurring stress within safe limits. However, it is very challenging to navigate the design space of cold bent glass panels because of the fragility of the material, which impedes the form finding for practically feasible and aesthetically pleasing cold bent glass façades. We propose an interactive, data-driven approach for designing cold bent glass façades that can be seamlessly integrated into a typical architectural design pipeline. Our method allows non-expert users to interactively edit a parametric surface while providing real-time feedback on the deformed shape and maximum stress of cold bent glass panels. The designs are automatically refined to minimize several fairness criteria, while maximal stresses are kept within glass limits. We achieve interactive frame rates by using a differentiable Mixture Density Network trained from more than a million simulations. Given a curved boundary, our regression model is capable of handling multistable configurations and accurately predicting the equilibrium shape of the panel and its corresponding maximal stress. We show that the predictions are highly accurate and validate our results with a physical realization of a cold bent glass surface.

A method to determine the emission measure and hence the effective extension of solar flares is described. The conditions for the Balmer continuum to be visible in disk flares is also considered. The concept of the effective mass is introduced and it is shown that this mass is a little less than that of a plasma filling the whole spectroscopic volume and including thin and dense filaments and the intervals between them as well. In this connection it is necessary to have high energy electron fluxes. It is assumed that these electrons maintian a high temperature in the interval volume; being a source of powerful X-rays, such hot intervals can heat cool filaments and they in their turn reradiate in the visible and ultraviolet regions of the flare spectrum. Taking one flare as an example, we give curves of the emission measure, effective mass and numbers of hydrogen atoms in the second quantum state versus time. These curves agree qualitatively with the light curve characteristics for most of the flares.According to modern concepts solar flares are structural features consisting of many thin and dense filaments. One of the methods to give evidence of such filamentary structures is the study of Balmer continuum in flares. This idea was first proposed by Svestka (1963). This problem was also studied by Kurochka (1970). It became necessary to explain the physics of the formation of such thin and dense filaments. A first attempt was made by Guseinov et al. (1971). Unlike selected limb flares, in disk flares the Balmer continuum has never been observed. Therefore one cannot estimate its emission measure nZ~L and hence the effective extension L for a known electron density n e. From the non-existence of the Balmer continuum we can only determine the upper limit of the emission measure and thus with a known ne value only the upper limit of the effective extension L.In our method for determining the emission measure the ionization-recombination equilibrium is taken into account for every individual level (Polupan and Yakovkin, 1965). We also assume that the Balmer continuum may be discovered in disk flares only when its intensity Iz2 amounts to >~2% of the intensRy of the continuous spectrum of the solar disk i.e. I~2 ~> 5.4 x 1012 erg cm-3 s-1 ster-1.

BYAmong the A1' BV1 binary systems, one of the most complex and little studied is the In-S system in which three stable compounds exist, namely Ins, p -In2S3, and In6S7 crystallizing in an orthorhombic (Dzh), a tetragonal (Dqh)? and a monoclinic (sh) structure, respectively /I to 4/.The long-wave optical phonons of Ins and p-In2S3 compounds were studied elsewhere /5 to 9/. In another study /lo/, non-polarized IR reflection spectra of an In S single crystal were measured in the frequency region from 100 to 400 cm , and only two reststrahlen bands with frequencies of 203 and 313 cm" were found. In an earlier study /11/ we investigated IR reflection spectra of In S single crystals in the frequency range from 40 to 400 cm" at 3 1 g, as a result of which we revealed and identified 16 modes.