Glass Articles Research Articles

Beykoz Glassware and Elements that Shaped It in the Nineteenth Century

Introduction Beykoz glassware owes its name to a region in Istanbul, Turkey where glass articles were produced in glass workshops and factories during most of the nineteenth century. Although the production of Beykoz-style items continues today, the number of original nineteenth-century Beykoz glass products is relatively small. Found only in museums and in private collections, they have become precious collectors’ items that represent a cultural heritage. This article provides a short history of this particular product family and an examination of the intangible elements that shaped it. We explore the links between the cultural elements, cultural transformation, daily life, industrial developments, and design of Beykoz glassware in a historical context. Although a rich variety of Beykoz ware was created, characteristic products included laledan or tulip vases, rose water sprinklers, bird-shaped perfume containers, ewers, sherbet cups, and Venetian-style products known as cesmibulbul (cheshmibulbul). The production of glassware was supported by the Ottoman court as part of a large-scale industrialization effort. Luxurious glass and porcelain items flooded the Ottoman capital as a new market emerged—on that resulted from the modernization efforts of the Sultans. Glass items produced at Beykoz could only partially satisfy the appetite of the elite Ottoman families and the nonMuslims leading the cultural transformation. The remaining demand was satisfied mostly by glass products imported from France and Bohemia.1

J045014 ガラス製品の最終処理による脆性改善 : ガラスの低環境負荷強靭化処理([J045-01]知的材料・構造システム(1))

J045014 ガラス製品の最終処理による脆性改善 : ガラスの低環境負荷強靭化処理([J045-01]知的材料・構造システム(1))

Relaxation phenomena in glass technology

Investigations of relaxation phenomena in glasses are reviewed. The role of such phenomena in the formation and heat-treatment as well as in other technological processes is shown. The characteristics of the surface layer are indicated from the standpoint of the physics of mesomechanics and the general structural features of inorganic glasses. A number of operational reliability factors for glass articles are examined.

Application of the Abel inversion in case of a tensor field

Abel's integral equations arise in many areas of natural science and engineering, particularly in plasma diagnostics. The axisymmetric physical field is determined using the Abel inversion. Until now, the Abel inversion has been applied almost exceptionally for the determination of scalar fields, i.e. fields, which at a point are characterized by a scalar. In several areas of engineering, the need to determine axisymmetric tensor fields arises, for example by measuring residual stress in axisymmetric glass articles with photoelasticity. In this article, we show how the Abel inversion can be used for the determination of an axisymmetric stress tensor field. The peculiarity in determining the tensor field is that on every ray two integrals of the field are measured and for complete determination of all the components of the stress tensor, equations of the theory of elasticity are used. The method is illustrated by an example.

Characteristics of the changes in the deformation properties of glass-forming melts

The basic principles of rheology are stated. The basic rheological properties during flow and some structural characteristics of silicate glass-forming melts are presented. The characteristics of the changes occurring in the deformation properties of molten glass during the manufacture of glass articles, specifically, glass containers, are indicated.

Edge-strengthening of flat glass with acrylate coatings

Edge-strengthening is a novel technology used to strengthen glass by applying a coating only on the edges. In this work, edge flaws of flat glass articles were examined in detail via scanning electron microscope (SEM) imaging. Then the effect of using weatherable acrylate coatings on edge-strengthening of flat glass was determined. Four-point bending measurement showed that the coatings provided more than twofold increase of the mean flexural strength and a factor of about two increase of the tensile stress needed to reach 0.8% cumulative probability of failure. The coatings were found to cover the flaw zone at the glass edges and partially fill in the cracks. Different surface treatments led to different levels of strengthening, indicating the importance of coating adhesion. The coating’s thermal and mechanical properties affected the extent of strengthening effect. A coating formulation with a higher glass transition temperature tended to provide a better strengthening effect, indicating the importance of closure stress within cracks generated during film curing process. Challenges of applying the edge-strengthening technology are also discussed.

Dishwasher Corrosion of Glasses

Dishwasher resistance of glass articles is one of the most important quality criteria for glass tableware manufacturer. Dishwasher corrosion of glass and the resulting formation of unacceptable appearance limits the lifetime of glass tableware in private households and even more in professional catering business where constant replacement of glass tableware is a considerable cost factor. Usually glasses undergo through some reactions in an atmospheric corrosion process, which is known as “weathering” or “warehouse effect”. This phenomenon is found to trigger the formation of defects during dishwashing and, visible defects such as cloudiness and iridescence are formed on the glass surface after certain dishwasher cycles depending upon the degree of the atmospheric corrosion that has already been formed on the surface prior to washing. Consequently atmospheric corrosion resistance is an important parameter for dishwasher resistance. The present paper comprehensively investigates the glass corrosion behavior during dishwashing and the effect of glass composition on improved dishwasher resistance by rendering the glass less prone to atmospheric corrosion even under severe conditions.

Modern Photoelasticity for Residual Stress Measurement in Glass

Abstract: This paper gives a review of modern photoelastic technology for residual stress measurement in various glass articles, including glass articles of complicated shape. For residual stress measurement in axisymmetric glass articles, integrated photoelasticity is being used by many glass companies and research laboratories. In case of non‐axisymmetric glass articles of complicated shape, photoelastic tomography is used. As for automotive and architectural glass panels used in buildings, surface stress can be measured with the mirage method. More complete stress analysis can be carried out with the scattered light method. The paper is illustrated by numerous examples.

Editorial

Editorial

Light losses in sol-gel coatings

It is shown that the translucence of a substrate strongly influences light transmission by glass articles modified by sol-gel coatings. In contrast to glass, where light scattering is proportional to the refractive index, an inverse proportionality has been found in the films studied, which can be explained by the influence of porosity on the decrease of the refractive index of the coating.

Approximate Solution of the Inverse Problem of Axisymmetric Thermoelasticity for Residual Stress Measurement in Glass

By the measurement of residual stresses in axisymmetric glass articles with integrated photoelasticity the stress components σ z and σ rz can be measured directly. For determining also the stress components σ r and σθ, equations of equilibrium and those of axisymmetric thermoelasticity can be used. However, solution of the inverse problem of the equations of thermoelasticity is not unique. Using the perturbation method it is shown that if stress gradient in the direction of the z axis is constant, a unique solution of the problem is obtained.

Experience in using separators based on rare-earth permanent magnets to enrich nonmetalliferous materials

Erga NPF is the leading manufacturer of rare-earth permanent magnets and equipment based on them. When used for enriching the initial materials for making glass such equipment sharply reduces the Fe2O3 content in the initial materials and thereby improves the quality of the manufactured glass articles.

Characteristics of colored inorganic–organic hybrid materials

Inorganic–organic hybrid glasses are relatively new nanometric materials of Ormosil’s group (organic modified silicates). There co-existence, on a molecular scale, exists between inorganic structures in the form of silica-oxide network and organic structures based on carbon links. Properties of these materials are intermediate between those of inorganic glasses (hardness, chemical and thermal resistance) and organic polymers (low temperature of obtaining, elasticity of structure). The hybrid materials are compatible matrices for organic compounds such as organic dyes, laser dyes, photo-chromic compounds, etc. Inorganic–organic hybrid glasses are usually produced in the form of thin coatings on various bases using a low-temperature sol-gel process. These coatings, depending on the kind and amount of units, building their structure, show various properties: refractive index changing in a wide range, anti-static properties, anti-reflection, corrosion protection, intensive color, luminescence and others. That is why these materials found application as protective and colored covering of glass articles as well as in new technical areas. The aim of this paper is obtaining and characterizing colored inorganic–organic coatings on glass, considering both protective and colored properties. These materials have been produced from phenyltriethoxysilane (PhTES), 3-glycidoxypropyltrimethoxysilane (GPTMS), aluminium tri-sec-butylate (TBA); (PGT matrix). The structure of PGT matrix was determined using the FTIR, 29Si MAS NMR and 27Al MAS NMR examinations. It has been found that chemical bonds occur between structural units. The two groups of organic dyes were used for coloring the coatings. The first group consisted of ORASOL dyes, chiefly based on various metal complexes. These dyes have a wide range of commercial utilization. The second group included the organic, intensive dyes obtained in the laboratory and are inaccessible for sale. The coloring coatings were coated on flat glass using the dip-coating method. The samples were submitted for thermal treatment at temperatures of 100 and 200 °C. Investigation of chemical resistance (boiling in water for 1 h) was made for coated materials after thermal treatment at 100 °C. UV–VIS transmission of colored coatings was examined after each stage of thermal treatment and also after hydrolytic resistance examination. The quality of the coatings and their thickness were estimated by SEM observations. The obtained, inorganic–organic coatings were characterized by good chemical resistance and stability of color.

Chemical behaviour of metallic inclusions in glass melts

Inclusions of all kinds cannot be accepted in glass articles. Most of them are non-metallic stones, silicon spheres, cords, bubbles, and sometimes metallic inclusions. Identification of every appearance is not possible, since body structure and chemical composition do not compare. Laboratory experiments regarding the behaviour of the metals copper, brass and iron and their dissolution mechanisms in glass melts at technological relevant temperatures were analysed. Besides partial oxidation processes, sulphidic species were found. The experiments have been compared with thermodynamic calculations of several reaction mechanisms.

Color control and redox balance monitoring in container glass

Modern methods and systems for monitoring the redox balance in glass as a key parameter for stabilizing the glassmaking process and attaining reproducible prescribed functional properties of glass and glass articles are examined. It is shown that the value of the trichromatic characteristics — the dominant wavelength, purity, and brightness of the color — must be used to monitor the light protection function of glass.

Modelling of heat transfer at glass/mould interface in press and blow forming processes

Numerical models may play an important role in the optimization of the quality of hollow-ware glass articles in glass industry. Due to the complexity of the phenomena involved a coupling between thermal and mechanical aspects is crucial. One of the key aspects required is a deep knowledge of the heat transfer at the glass/mould interface, a factor that may influence dramatically the final product. In this work an interface element developed to deal with heat transfer between glass and moulds in glass forming processes was introduced in a commercial code as a user element. The initial purpose was to make it possible to consider the dependence of the interface heat transfer resistance on process parameters like glass temperature and viscosity, mould temperature and contact pressure. In addition its implementation also proved to be an efficient tool to eliminate some perturbations introduced by the penalised form adopted in the commercial code to deal with non-matching meshes. A press and blow forming simulation of a Champagne flute was performed to assess the element performance on a real case study.

Micro- and macro-cellular sintered glass-ceramics from wastes

Glass obtained from melting a mixture of industrial wastes (panel glass from dismantled cathode ray tubes, mining residues from feldspar excavation and lime from fume abatement systems of the glass industry) has been employed for manufacturing micro- and macro-cellular sintered glass-ceramics. Micro-cellular glass-ceramics, with a closed porosity, were prepared by the direct foaming of the glass mass, determined by viscous flow sintering of fine powders (<37 μm), due to addition of a SiC-based waste (from the polishing of glass articles). The surface crystallization of glass, upon sintering, limited the porosity (being about 50%), but imparted a remarkable crushing strength to the products (up to about 80 MPa), useful for construction applications. Micro- and macro-cellular glass-ceramics, with an open porosity and very low relative density (from 40 to less than 10%), were prepared by the sintering of fine glass powders mixed with sacrificial poly-methyl methacrylate microbeads or deposited on sacrificial poly-urethane sponges. The crystallization, besides imparting a good mechanical strength, allowed the maintenance of the open-celled morphology, useful for filtering applications.

Reutilization and stabilization of wastes by the production of glass foams

Glass foams are known to represent highly valuable products for thermal and acoustic insulation, often produced by employing wastes. Although the usage of recycled glass is widely reported for developing the glass matrix, little research has been due to the usage of wastes for the foaming reaction. In this work the cellular structure is achieved after oxidation of SiC-based wastes coming from the polishing of glass articles. The foamed recycled soda-lime glass incorporated the residues from oxidation and provided a reasonably good chemical stability. The addition of MnO 2 to the starting mixtures of wastes led to a certain improvement of the oxidation of SiC, and a complex effect on the correlation between density and mechanical strength. For selected additions, a more homogeneous foaming was found to provide a stronger cellular structure.

Production of white pigments based on zirconates and titanates using the precipitation method

Experimental data on the synthesis of zirconates and titanates of s and d elements of group II by the precipitation method are summarized. It is established that a chemical reaction takes place between the components under alkaline precipitation. Subsequent thermal treatment of the obtained precipitate makes it possible to synthesize materials with a perovskite-like structure, which are recommended as white pigments for producing paints suitable for decorating glass and enamel articles.

Lead-Free Paint Coatings for Glass Articles

The effect of binders on the quality of paint coatings based on lead-free enamels and meeting the requirements of standard TU RB 100029049.030 is considered. It is established that enamel compositions can be prepared using 20% solution of oxyterpene resin in turpentine and 2% alcoholic solution of Na-carboxymethyl cellulose of grade 7MF. The use of an aqueous solution of dextrin as a binder deteriorates the quality of enamel coatings: it produces color modifications, loss of luster, and formation of crackle.