Chemical analyses of ancient glass findings excavated in the Venetian lagoon

Although Venice is regarded as being one of the most important centres of glass manufacture and trade in Western Europe, little is known about the origins of the Venetian glassmaking. Some archaeologists suggest there is a continuity in the history of glass making, in its transplantation from the Roman centres of the mainland (Altino and Aquileia), first to some islands of the lagoon, and later to the town. Some others, instead, think that there was no continuity at all and that the art of glassmaking was imported in Venice from the Islamic glass factories of the Middle East. Of great help in answering this and other technological questions is the information about the composition of ancient glass from well-dated excavations that allows to conclude on the early technology, sources of raw materials and long-distance trade. Some significant glass findings, including fragments of pots used for glass melting, were found on the island of Torcello and, more recently, in two emergency excavations in the historic centre of Venice. In this paper, the chemical composition of a large set of glass findings (and related materials) from the Venetian lagoon dating from the 7th to the 13th centuries is determined by X-ray microanalysis in order to throw new light on the glassmaking technology in the early centuries of the Venetian tradition. The results show that in this period there occurred a gradual transition from the Roman technique (a two-ingredient formulation with silica-lime sand and natron as a fluxer), towards the use of silica sand and soda plant ash. There is evidence, therefore, for a production continuity with the Roman period (melting pots and glass scraps with a natron-based composition), yet restricted to transparent blown items. No evidence was found for a local production of glass tesserae for the mosaics of the church of St. Maria Assunta in Torcello.     

Optimal control of end-port glass tank furnace regenerator temperature based on artificial neural network

1 Introduction1 The principle controlled target of an end-port glass tank furnace regenerator is the melting temperature which is regulated by the flow of oil or gas. The disturbances stem from feed-in glass powder, the pressure, value and atomization of fuel, the secondary wind, the tank furnace pressure, etc. Among them, some can be controlled and some cannot. In order to keep the temperature steady, a cascade ratio regulating system is designed, in which the temperature adjustment functions…     

Two Stangengläser from the collection of the Museum of Decorative Arts in Prague: Decorative techniques,material analyses,and conservation

Abstract

The two Stangengläser, tall cylindrical vessels from the beginning of the seventeenth century, are described in detail. The severely damaged Stangengläser, decorated with diamond-point engraving and cold-painting, were challenging to treat. Research preceding the conservation revealed differences in decorating techniques. Samples of the paint layers were analyzed using micro-Fourier transform infrared spectroscopy. Two layers of resinous varnish with a middle layer of paint containing a plant gum were found on the Stangenglas with Allegory of Caritas and Zierotin coat of arms. In the plain paint layer of the Stangenglas with dancing couples, egg white was identified as the binder. The glasses, analyzed using scanning electron microscopy with energy dispersive X-ray spectrometry, had similar potash–lime–silica compositions, which seems to be characteristic for glass from Bohemian lands. Results of analysis contributed to the discussion about the possible provenance of the Stangengläser, the glassworks at Wilhelmberg, South Bohemia.     

The Absence of Father in The Glass Menagerie

In English literature, the absence of father is not a new theme. In The Glass Menagerie, the father Mr. Wingfield as the fifth character is absent. This paper will discuss from the angle of the father's absence, through analyzing the effects of his absence,the reader can realize the importance of father's existence and see the social realities reflected from the play.     

The glass-melting furnace and the crucibles of Südel (1723–1741, Switzerland): provenance of the raw materials and new evidence of high thermal performances

Fifty crucible fragments and 10 fragments of the melting furnace of the forest glassworks of Südel (1723–1741, Ct. Luzern), were analyzed by petrographic, mineralogical and chemical techniques in order to assess the temperature reached in the melting chamber and to find out which raw materials were used to make the crucibles and the melting furnace. Since the crucibles were used in the melting furnace, the temperature estimations were based on both the crucibles and the refractory fragments, as they were parts of the same system. The temperature range in the melting chamber, estimated by the structural order of the new-formed cristobalite, points to a temperature range between 1350 and 1500 °C. However, three crucible samples recorded extreme temperatures as high as 1650 °C, suggesting very high flame temperatures for wood fuel. The analyzed red bricks were made with local calcium-poor clay. One of them was tempered with refractory fragments, demonstrating an in-house production and the recycling of such a material after its use. The crucibles and the refractory bricks were made with the same refractory clay. The former using unprocessed clay and the latter blending clay with chamotte. A comparison with Sidérolithique clayey sand samples from the Swiss Jura, shows strong affinities which may rule out the archaeological hypothesis of an exclusive provenance of such clays from Germany, suggesting an import from the Swiss Jura mountains.     

“寻找你自己”——解读巴塞尔姆的《玻璃山》

即使是被描述为无意义写作的后现代小说．也是作者思考的产物,是作家人生观、价值观、社会观等意识形态的体现。巴塞尔姆在《玻璃山》中颠覆了日渐腐朽的“美国梦”,提出“寻找你自己”,鼓励现代社会的美国人走出混乱的精神领域,寻找自我的精神升华。     

美,从未缺席——论曹文轩《蜻蜓眼》的诗性追求

曹文轩是一位学者型作家,他认为文学作品需要思想,也需要美感。他的最新作品《蜻蜓眼》通过对美好的女性形象、优美的意象和永恒的人性之美的书写,构建了一个充满诗意和美的世界,体现了他的古典美的美学追求。     

浮法玻璃缺陷检测中的模式识别处理

目前,在基于机器视觉的浮法玻璃质量在线监测系统中,首先需要对玻璃图像进行采集,对其进行处理和分析,以进行玻璃缺陷识别,然后用于后续操作中。本文根据对浮法玻璃各类缺陷的特征研究,通过分析反向传播学习神经网络识别算法的优缺点,采用一种改进方式用于浮法玻璃的缺陷分类和字符识别。经过实验数据测试表明,改进后的算法具有收敛速度快、识别误判率低的特点,能够为浮法玻璃质量在线检测系统中的玻璃打标和切割等操作提供准确、有效的信息,对于减少人工误差、保证产品质量等方面具有重要的意义。     

Nonlinear effect induced in thermally poled glass waveguides

INTRODUCTION Because of high transparency of glass to light and the very stable physical properties of glass, waveguides made of it are popular structures and building blocks in optoelectronic applications. Par- ticularly they are often used to fabricate passive components or devices with good compatibility with optical fibers in optical communication. By adopting the technology available in microelectronics, fabri- cation of glass waveguides can be a standard process with mass production,…