Change in the ratio of the weight of the finished glass article to the gob

1974 ◽  
Vol 31 (8) ◽  
pp. 543-544
Author(s):  
A. A. Rudakov ◽  
G. Sh. Pruslin
Keyword(s):  
Glass Article ◽  
Finished Glass

scholarly journals Laser finished glass edges with compressive stress

2020 ◽  
Vol 10 (2) ◽  
pp. 597
Author(s):  
Stuart Gray ◽  
Todd L. Heck ◽  
Miya Hsieh
Keyword(s):  
Compressive Stress ◽  
Finished Glass

scholarly journals Separation and Surface Nuclei Effects in a Cavitation Susceptibility Meter

1991 ◽  
Vol 113 (4) ◽  
pp. 695-698 ◽  
Author(s):  
L. d’Agostino ◽  
A. J. Acosta
Keyword(s):  
Laminar Flow ◽  
Flow Velocity ◽  
Flow Separation ◽  
Laser Doppler Velocimeter ◽  
Local Flow ◽  
Applied Tension ◽  
Upstream Pressure ◽  
Finished Glass ◽  
Cavitation Nuclei ◽  
Glass Surfaces

This work is concerned with the effects of flow separation and surface nuclei on the operation of a fixed geometry Cavitation Susceptibility Meter (CSM) with laminar flow. Cavitation is induced under controlled conditions at the throat of a glass venturi tube for the measurement of the active nuclei concentration in water samples as a function of the applied tension. Both cavitation and flow velocity are monitored optically by a Laser Doppler Velocimeter. The throat pressure is determined indirectly from the upstream pressure and the local flow velocity. The results show that laminar flow separation and surface nuclei effects are the most stringent operational limitations. Separation in the diffuser increases the minimum attainable throat pressure above the susceptibility of most cavitation nuclei commonly found in technical waters. Surface nuclei can generate extensive sheet or spot cavitation at relatively high tensions even on optically finished glass surfaces. These phenomena are difficult to eliminate and bring therefore into question the practical utility of CSM’s with laminar flow and fixed geometry for the measurement of the dependence of the cavitating nuclei concentration over wide ranges of the applied tension, as required for cavitation studies.

scholarly journals Semi-finished glass from Ile-Ife, Nigeria: implications for the archaeology of glass in sub-Saharan Africa

Antiquity ◽  
2020 ◽  
Vol 94 (375) ◽  
Author(s):  
Abidemi Babatunde Babalola ◽  
Adisa Benjamin Ogunfolakan ◽  
Thilo Rehren
Keyword(s):  
Sub Saharan Africa ◽  
Finished Glass ◽  
Sub Saharan

Abstract

scholarly journals The Glass Making Crucibles from Ile-Ife, SW Nigeria

2018 ◽  
Vol 16 (1) ◽  
pp. 31-59 ◽  
Author(s):  
A.B. Babalola ◽  
Th. Rehren ◽  
A. Ige ◽  
S. McIntosh
Keyword(s):  
Raw Materials ◽  
Compositional Analysis ◽  
Refractory Clay ◽  
Sub Saharan Africa ◽  
15Th Century ◽  
Southwest Nigeria ◽  
Finished Glass ◽  
Sub Saharan ◽  
Glass Working

Abstract Crucibles to melt glass are very rare in archaeological contexts in sub-Saharan Africa. Recent archaeological excavations at Igbo Olokun, Ile-Ife (Southwest Nigeria) revealed abundant fragments of glass crucibles from 11th-15th century AD deposits, matching the complete and near complete examples earlier reported from Ile-Ife. This paper provides an in-depth examination of these crucible fragments in order to understand the material quality of the crucibles, their typology, and their functions in glass- working/making. Optical microscopic and scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) analyses were carried out on ten crucible samples. The composition of ceramic fabrics and the adhering glass are presented and discussed in view of their function. The crucibles were produced from specifically selected highly refractory clay and used for melting glass from its raw materials; colorants were added to the melt in the crucible. The useable capacity of the crucibles varied from 1 to 7 liters, equivalent to about 2.5 to 17.5 kg of finished glass for each crucible. Compositional analysis of a sample of the thousands of glass beads from the excavations indicates that the crucibles were used to melt the glass used in the beads. Archaeological evidence of glass bead making at this scale has not previously been reported from West Africa. The crucibles are unique evidence of indigenous glass-working/making in Sub-Saharan Africa from early through mid-second millennium AD.

scholarly journals ON COBALT USAGE IN THE OLD RUSSIAN PRODUCTION OF LEAD GLASS

2020 ◽  
Vol 23 ◽  
pp. 144-152
Author(s):  
A. EGOR’KOV ◽  
Keyword(s):  
Detection Limit ◽  
Analytical Methods ◽  
Glass Article ◽  
Lead Glass ◽  
Old Russian ◽  
New Information ◽  
The City ◽  
Different Sources ◽  
Blue Coloration ◽  
Cobalt Blue

In the Old Russian glassmaking, beginning in XI century and based on the production of lead glass, cobalt was used very rare. Until recently only three assured cases of cobalt usage for blue coloration of bracelets and beads were fixed. In addition, two cases of probable cobalt coloration were published in the middle of the preceding century, but owing to weakness of analytical methods of those times, the presence of cobalt was under detection limit. During the last twenty years another seven samples containing cobalt were analyzed by the author. These bracelets and beads were excavated in Old Russian towns and cities such as Suzdal, Vladimir, Smolensk, Tver, Dmitrov. All artifacts occurred from the strata of pre-Mongolian time dated to XI–XIII centuries and manufactured of potash lead glass. In addition, one blue bracelet of this type comes from Bolgar, the city of medieval Volga Bulgaria, and was analyzed in Kazan University. These analyses together with the two earlier ones are present in the table. The earliest Russian glass article, coming from Kievan St. Sophia Cathedral founded in 1036, only with a high portion of doubt can be determined as a product of Russian workshop. As opposed to all other analyzed artifacts it is a piece of tessera from one of the earliest Russian temples, and demonstrates an extremely high content of cobalt side by side with enhanced content of sodium. This glass, as well as two other artifacts, contains antimony, probably used as opacifier. Another common feature of all samples with antimony is higher content of calcium. One artifact has an enhanced content of manganese, whereas in two others the blue coloration had not been achieved. In spite of some new information for cobalt usage these facts indicate that cobalt blue colorant was imported to Russia occasionally from different sources and tradition of its usage in the pre-Mongolian time had not been developed.

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