Quantitative morphological analysis in a SEM-microcomputer system-II. Morphological analysis of complex SEM images

A Multiproxy Approach to the Reconstruction of an Ancient Manufacturing Technology: A Case Study of a Faience Ptolemaic Bowl from Tell Atrib (Nile Delta)

Faience objects produced from the fourth millennium BC in ancient Egypt are considered as the first high-tech ceramics in human history. Despite extensive studies on manufacturing technology, many aspects of this complex technology remain a mystery and there is no methodology in place to unravel the techniques of Egyptian faience object production. Detailed studies presented herein fill the gaps, verifying standing opinions and allowing certain aspects of faience manufacturing technology to be reconstructed. The object of this innovative investigation is a hemispherical faience bowl discovered by archaeologists excavating a Ptolemaic workshop district at the site of Tell Atrib in the southern Nile Delta. The multiproxy analysis included the application of specialised software and preparation techniques coupled with complementary methods of light and digital microscopy, SEM with EDS, XRD, STA with EGA, as well as image analysis. Sources of raw and accessory materials (mineral and organic binders, fluxes, colourants) used for preparing the silica paste and glaze slurry were determined. The results helped to reconstruct how the raw material was prepared and how faience vessels were made. The bowl was moulded by compression using a two-part mould. The moulded and dried bowl was then covered by glaze slurry using the application method. A synthetic colourant, Egyptian Blue, was probably used to colour the glaze. The item was fired once at a temperature of 1050–1150 °C. Oxidised conditions were maintained in the kiln during the firing process and firing at the maximal temperature was relatively short. Application of the multiproxy approach has shed light on the technological aspects of faience bowl manufacturing. The obtained results have confirmed the usefulness of the comprehensive methodology that was applied for the reconstruction of particular manufacturing stages of faience objects.

The formation of a structural framework in gelled Wyoming bentonite: direct observation in aqueous solutions

HYPOTHESIS

Particle space arrangement is a very important factor that determines the physico-mechanical properties of soil. Formations of three-dimensional (3D) structured networks within gelled or flocculated suspension may prevent clay particles and aggregates from settling under gravity force and by encapsulate water within such a network, lead to poor sludge dewatering. To better understand this phenomenon, a microstructural investigation of a smectite clay (SWy2) suspension was conducted.

EXPERIMENTS

SWy-2 was diluted in water and a moderately salty aqueous solution and was studied with the aid of a synchrotron-powered transmission X-ray microscope (TXM) and cryogenic transmission electron microscope (Cryo-TEM). Observations of mutual particle arrangement in 3D spaces were conducted within a natural water environment after vitrification without drying.

FINDINGS

A new type of micro-architecture in particle space arrangement was observed. Smectite flakes were mostly in edge-to-edge (EE) contact and formed a 3D network, confirming a "net of flakes" structural model. Clay particles form a complex and multi-hierarchic flocculated structure with characteristic cellular chained networking. Chained aggregates build cellular elements, encapsulating water inside closed voids. Increasing ionic strength results in the development of multi-hierarchic voids categories, with most water retained within nano-pores.