Glass casting

Abstract: The use of Dicor cast glass-ceramic material for fixed prosthodontic complete crowns has been described. The advantages of this material are chemical and physical uniformity, marginal accuracy, uncomplicated fabrication from wax-up to casting, ceramming, and coloring, ease of adjustment, excellent esthetics resulting from natural translucency, light absorption, light refraction, and natural color for the crown, and its inherent resistance to bacterial plaque.

Abstract: A novel glass brick facade has been designed and engineered to reproduce the original brick facade of a former townhouse in Amsterdam. Based on the original design the resulting facade comprises more than 6500 solid glass bricks, reinterpreting the traditional brick pattern, and elaborated cast glass elements for the replication of the window and door frames. To achieve unhindered transparency, the 10 by 12 m glass block facade has to be self-supporting. Previous experimental work by Oikonomopoulou et al. (J Facade Design Eng 2(3–4):201–222, 2015b. doi:10.3233/fde-150021) concluded that it was necessary to use a clear, UV-curing adhesive of high stiffness as bonding material. Experimental work on prototype elements indicated that the desired monolithic structural performance of the glass masonry system, as well as a homogeneous visual result, are only achieved when the selected adhesive is applied in a 0.2–0.3 mm thick layer. The nearly zero thickness of the adhesive together with the request for unimpeded transparency introduced numerous engineering challenges. These include the production of highly accurate glass bricks and the homogeneous application of the adhesive to achieve the construction of the entire facade with remarkably tight allowable tolerances. This paper presents the main challenges confronted during the construction of the novel facade and records the innovative solutions implemented, from the casting of the glass units to the completion of the facade. Based on the conclusions of the research and the technical experience gained by the realization of the project, recommendations are made on the further improvement of the presented glass masonry system towards future applications.

Abstract: In this paper, the feasibility to make molded glass–ceramics transparent in the second and third atmospheric window has been investigated. The thermodynamical and viscosity properties of the base glass have been measured confirming the possibility of generating crystals during molding at different temperatures. 71Ga nuclear magnetic resonance confirms that gallium plays the role of nucleating agent of gallium in this glass. Examination of X-rays diffraction patterns and optical properties indicates that the generation of nanocrystals of GeGa4Se8 allows the glass–ceramics to keep a wide transparency in the infrared range from 2 to 15 μm. The crystallization of large GeSe2 crystals of at higher temperature induces scattering and a reduced transparency window. The mechanical and structural properties of the as-prepared glass ceramics show an increase of toughness from 0.188 to 0.387 MPa m1/2 and elastic modulus from 22.7 to 26.55 GPa while the number and size of crystals increase. As a result, the preparation of molded IR glass–ceramics with high resistance to thermal and mechanical shocks has been clearly demonstrated.