Karen Privat

Chemical characterisation of archaeological glasses from the Hellenistic site of Jebel Khalid, Syria by electron probe microanalysis

BackgroundJebel Khalid is a single period Hellenistic site on the west bank of the Euphrates River in northern Syria. The occupation of the site dates from the early 3rd century BCE until its abandonment in the late 70s BCE. The so-called Governor’s Palace, an administrative centre on the Acropolis of the site, overlooked this walled Greek garrison city. A considerable quantity of glass, predominantly drinking bowls, was excavated from this building complex. This study concerns the elemental analysis of glass samples from this assemblage by electron probe microanalysis (SEM-WDS).ResultsThe preliminary analyses presented in this report reveal that the Jebel Khalid glasses are of the silica-soda-lime type fluxed with mineral soda, typical of late 1st millennium BCE glass composition. Manganese was employed as the chief decolourant. Glass compositions of monochrome bowls, core-formed and mosaic glass vessels are very similar, despite the different forms, colours and manufacturing techniques of the vessels.ConclusionsWhile the production centre for the Jebel Khalid glass remains elusive, the similarity to other published Hellenistic glasses from Greek mainland sites, Rhodes, Tel Anafa in Israel, and Gordion in central Turkey, indicates a tightly controlled composition with comparable batch ingredients. Without more comparative material of this date from the Near East and Greece, it is difficult to determine whether production of the vessel glass from this Seleucid site in the Near East occurred in the Aegean region or the Syro-Palestinian Levant, or both. Vessel style and archaeological context lean towards an Aegean connection, but until more comparative glass is analysed, and trace element and isotope data are considered, questions of primary and secondary production remain unresolved.

Biochar aging in contaminated soil promotes Zn immobilization due to changes in biochar surface structural and chemical properties

Adding biochar to Zn-contaminated soil can immobilize excess Zn and promote plant biomass growth. This was seen previously over the course of a 180-day planted pot trial involving two types of biochar (cattle manure, CM, and grain husk, GH) in a Zn-contaminated soil. Both biochars alleviated Zn-induced phytotoxicity to Ficus by immobilizing Zn and reducing its uptake by the plant, but to different extents. The aim of the current study was to delve into the in-soil mechanisms involved in biochar-mediated Zn immobilization. Biochar particles were excavated from the pot soils. Fresh and aged biochar particles were examined by high-resolution scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), field-emission electron probe micro-analyzer (EPMA), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The physical and chemical properties of the biochars had changed over the 180 days. SEM-EDS and EPMA indicated that organo-mineral micro-agglomerates had formed on biochar surfaces and in pores. Some of the Zn immobilized by the biochars was bound in the organo-mineral complexes of these agglomerates. XPS and FTIR showed that the complexes had a high concentration of oxygenated functional groups which facilitated Zn binding and encapsulation. The micro-agglomerates were similar in structure and composition to those observed on biochars having resided for much longer times in soils, or having been subjected to accelerated aging. Overall, Zn immobilization by the CM biochar was greater than by the GH biochar, due to its higher alkalinity, higher concentration of available negatively charged groups, and greater accretion of organo-mineral layers. These findings are suggestive that biochar-assisted phytorestoration of heavy metal-contaminated soils can be optimized through selection of biochar having such traits. It is hypothesized that metals may be continually taken up in such micro-agglomerates, since they continue to form over the lifetime of the biochar in the soil.

Engulfment Behavior of Inclusions in High-Carbon Steel: Theoretical and Experimental Investigation

Previous studies on inclusions behavior at the front of the solidifying steel shell have mainly focused on low-carbon steels. However, with the increasing applications of high-carbon steel in recent years because of its superior properties, it is crucial to understand this behavior in high-carbon steel. Most of the high-carbon steels are deoxidized by silicon, calcium treated, and contain higher sulfur percentage. Also, higher carbon content has a determining influence on the viscosity and surface tension, which will affect the inclusion behavior. In this study, we have investigated the engulfment behaviors of inclusions in front of the solidifying interface in high-carbon steels using concentric solidification method. The critical velocity of the growing shell, at which the particle is engulfed in the solidifying shell, instead of being pushed by this shell, was determined. The inclusion identified in this study is a bi-component form of CaO-SiO2-based oxide and CaS. It was revealed that engulfment behavior is strongly affected by convection of liquid steel that originates from carbon push out in high-carbon steels. This study provides new crucial information to produce high-carbon steel with fewer inclusions, which opens new application pathways for this emerging grade of steel.

Enhancing steel properties through in situ formation of ultrahard ceramic surface

Abrasion and corrosion resistant steel has attracted considerable interest for industrial application as a means of minimising the costs associated with product/component failures and/or short replacement cycles. These classes of steels contain alloying elements that increase their resistance to abrasion and corrosion. Their benefits, however, currently come at a potentially prohibitive cost; such high performance steel products are both more technically challenging and more expensive to produce. Although these methods have proven effective in improving the performance of more expensive, high-grade steel components, they are not economically viable for relatively low cost steel products. New options are needed. In this study, a complex industrial waste stream has been transformed in situ via precisely controlled high temperature reactions to produce an ultrahard ceramic surface on steel. This innovative ultrahard ceramic surface increases both the hardness and compressive strength of the steel. Furthermore, by modifying the composition of the waste input and the processing parameters, the ceramic surface can be effectively customised to match the intended application of the steel. This economical new approach marries industry demands for more cost-effective, durable steel products with global imperatives to address resource depletion and environmental degradation through the recovery of resources from waste.

Analysis of Molded and Coreformed Glass from 1 st Millennium BC Gordion, Anatolia

We report the analysis of glass vessels recovered from 1st millennium BC contexts at the site of Gordion, the ancient capital of the Anatolian Kingdom of Phrygia (in modern day Turkey). The Phrygians (c.8 th -7 th century BC) were renowned for their metalworking skills and produced vessels in a distinctive “Phrygian” style. While no archaeological evidence has yet been found to support local glassmaking, the presence of a highly-developed metalworking industry coupled with the discovery of colorless glass vessels molded in a typical Phrygian shape at Gordion have opened the question of a local glassmaking or glassworking industry within the kingdom [1]. Due to the significant concentration of molded glass vessels found at Assyrian Nimrud, and because of the well-established political interactions between Phrygia and Assyria, von Saldern has suggested that some vessels reached Gordion from Nimrud as diplomatic gifts [2]. EPMA of molded colorless glass vessels from Gordion was used to investigate vessel provenance and manufacturing techniques. In addition to the Phrygian material, molded colorless glass vessel fragments recovered from later Hellenistic (4 th -3 rd c. BC) contexts at Gordion were analyzed to examine changes in glassmaking technology and provenance over time.

Materials design considerations involved in the fabrication of implantable bionics by metallization of ceramic substrates

The Pt metallization of co-fired Al2O3/SiO2 substrates containing Pt feedthroughs was shown to be a suitable means to construct implantable bionics. The use of forge welding to join an electrode to such a metallized feedthrough was demonstrated and subsequently evaluated through the use of metallography and electron microscopy. Metallurgical phenomena involved in forge welding relevant to the fabrication of all types of biomedical implants are discussed within this paper. The affect of thermal profiles used in brazing or welding to build implantable devices from metal components is analysed and the case for considered selection of alloys in implant design is put forward.

Technology and Trade at Ancient Gordion: Insights from Microanalysis of First Millennium BCE Glass

In the first half of the first millennium BCE, the ancient city of Gordion, in central Anatolia, was the capital of the kingdom of Phrygia. Still famous as the home of King Midas, Gordion was situated on major east-west trade routes and arterial rivers, and provided a link between surrounding Near Eastern states and between these states and the Greek world further to the west. Excavations at Gordion have yielded a number of monochrome glass objects, mainly vessels, from the Phrygian period (Iron Age, 9-7 c. BCE) and later Hellenistic period (mid-4 to early 2 c. BCE). We undertook electron microprobe analysis (WDS) of a set of 51 glass samples from Phrygian, Hellenistic and undated contexts at Gordion in order to examine similarities and differences among glass of the two periods, and to investigate broader technological and economic relationships between Phrygian and Hellenistic Gordion and its neighbors.