Liquid phase heterogeneous catalysis — deeper insight : novel transient response technique with ESI-MS as a detector

Processes in the chemical industry convert readily available startingmaterials tomore\ud valuable product molecules. Catalytic materials are used in these processes to accelerate\ud chemical transformations so that reactions proceed in a highly efficient manner,\ud achieving high yields of desirable products and avoiding unwanted by-products.\ud Compared to classical stoichiometric procedures, catalysts often allowmore economical\ud and environment-friendly production.\ud Development of heterogeneous catalysts for liquid the phase processes requires\ud detailed knowledge about phenomena that occur on the catalyst surface during the\ud catalytic reaction in liquid phase. Transient response techniques with detectors that\ud can perform continuous, rapid, multi-component and simultaneous detection are\ud ideal for such studies. However, there are hardly any transient techniques available\ud that allow experimental investigation of the adsorption of reactants, intermediates\ud and probe-molecules from liquid phase on the surface of catalysts. The existing liquid\ud phase detectors are not able to detect more than one specie simultaneously and\ud rapidly, making the more detailed study of the catalytic reaction mechanisms impossible.\ud The work described in this thesis focuses on development and application of a\ud transient response technique for studies of adsorption and catalytic reactions over\ud heterogeneous catalysts in liquid phase with Electro-Spray Ionization (ESI-MS) and\ud Membrane Inlet Mass Spectrometry (MIMS) as detectors. Two test reactions, i.e. reduction\ud of nitrite over Pt/SiO2 and oxidation of glucose over Pt/CNF/Ni catalysts, were\ud used to demonstrate that it is possible to monitor reactants, intermediates and products\ud during reaction in (semi)quantitative manner. Nitrite hydrogenation is a relevant\ud reaction for both nitrate to nitrogen de-nitrification of drinkingwater, aswell as nitrate\ud hydrogenation to hydroxyl-amine, an intermediate in the production of caprolactam.\ud Oxidative conversion of glucose is important in view of the anticipated shift towards\ud renewable feedstocks for the chemical industry. Glucose can be upgraded to more\ud valuable compounds e.g. gluconic acid, a building block for production of chelating\ud agents

Pločnik: technology of metal production

Metallurgical materials recovered during the excavation campaigns of 2012 and 2013 in Pločnik show similar characteristics to samples already studied and published previously (Radivojević 2012, 2015; Radivojević and Kuzmanović Cvetković 2014; Radivojević and Rehren 2016; Radivojević et al. 2013). They include, as for Belovode (Chapter 11), predominantly malachite minerals and ores (Table 1), that occur as roughly beneficiated pieces and without a distinct spatial patterning in Trench 24. In comparison to Belovode, they occur less frequently across all five horizons, partially explained by the fact that most of Trench 24 is a large rectangular feature – a house (F1=F2=F4=F5=F6=F10), and there is very little economic area surrounding it

Description of three populations of Xiphinema dentatum Sturhan, 1978 from Yugoslavia and observation on X. turcicum Luc & Dalmasso, 1964 (Nematoda : Longidoridae)

Trois populations de #Xiphinema dentatum provenant de régions montagneuses de Yougoslavie sont décrites. Les caractéristiques morphologiques et biométriques sont étudiées et comparées avec celles des autres populations de #X. dentatum précédemment décrites pour réévaluer la variabilité et les limites de cette espèce. Des épines ont été observées pour la première fois dans l'utérus de spécimens de la population type de #X. turcicum$. (Résumé d'auteur

Belovode: past, present and future

The 2012 and 2013 excavations and subsequent post- excavation analyses by The Rise of Metallurgy in Eurasia project team at the site of Belovode built upon two decades of earlier work led by the National Museum of Belgrade and the Museum in Požarevac (Jacanović and Šljivar 2003; Šljivar 2006; Šljivar and Jacanović 1996b, 1996c, 1997c; Šljivar et al. 2006). This earlier work across 17 trenches had identified four building horizons (Belovode A–D), the presence of the entire Vinča culture ceramic sequence from Vinča Tordoš (A–B1) to the Gradac Phase (I–III) as well as stone tools, figurines, obsidian blades, animal bone and, most importantly for the current research, evidence for the smelting of copper ores. As detailed in Chapter 5, it was the archaeometallurgical analysis of five small copper slags from Trench 3 together with the radiocarbon dating of the excavated horizon in which they were found that provided evidence for copper smelting at c. 5000 BC (Radivojević et al. 2010a) and the foundation for The Rise of Metallurgy in Eurasia project. However, in the absence of any detailed publication on these earlier excavations at Belovode, further questions relating to broader context of the earliest evidence for copper smelting could not be explored

Balkan metallurgy in a Eurasian context

As outlined in Chapter 2, three key lines of enquiry shaped The Rise of Metallurgy in Eurasia project and underpinned the research questions. Firstly, there are competing views about whether metallurgy in Eurasia had a single origin or arose in multiple places. There are also different perspectives regarding the ways in which pre-existing technical knowledge influenced and inspired the emergence of this new technology. Further discourse relates to the manner in which this early metallurgy was organised across the chaîne opératoire of metal production and use and developed across a range of metals and alloys. Each of these three themes are fundamental to early metallurgy across the world (see papers in Roberts and Thornton 2014). These are areas of investigation with a deep history of scholarship and a wide range of competing explanatory models

Belovode excavation results

The Neolithic–Chalcolithic site of Belovode covers approximately 40 ha (Figure 1). In the two fieldwork campaigns of 2012 and 2013, only 31.5 m2 was excavated due to the archaeometallurgical focus of the project. The trench was positioned on the eastern platform of the settlement, where previous excavations had uncovered significant metallurgical evidence in Trenches 3 (Šljivar and Jacanović 1997c, Radivojević et al. 2010a) and 17, which are located to the north and the south of Trench 18 respectively. A 5 x 5 m area was opened in the 2012 season and then, based on the preliminary spatial analysis of metallurgical finds, in 2013 the trench was slightly expanded with a 2 x 3 m extension on the eastern side