We studied the corrosion of Roman copper alloy coins that experienced alternations or progressive changes in their burial environment. We used coins that were still embedded in soil or in a... Show moreWe studied the corrosion of Roman copper alloy coins that experienced alternations or progressive changes in their burial environment. We used coins that were still embedded in soil or in a concretion selected from three professional excataved sites - Berlicum and Krommenie in the Netherlands and Kempraten in Switserland. mCT scanning and neutron scanning were used to record the 3-D properties of these coins prior to (destructive) analyses. It proved possible to tentatively identify the coins. Microscope observations and SEM-EDX analyses revealed complex corrosion processes, related to changing burial environments. In soil horizon with fluctuating groundwater levels in a region with upwelling reducing, iron-rich groundwater, the copper in a gunmetal coin is essentially replaced by iron oxides while tin remains and forms tin-oxide bands. Fluctuating redox conditions in marine-influenced environments was shown to transform a copper-alloy coin into strongly laminated copper sulphides with embedded gypsum crystals, with an outer surface of copper and copper-iron sulphides. Burial of bronze in a charcoal rich layer probably caused temporary highly alkaline soil conditions. This caused most of the copper to leach from this coin, leaving behind a laminated tin-dominated mass, with only a limited amount of (malachite) corrosion products remaining in the surrounding groundmass. In all three cases, corrosion processes tend to be anisotropic, probably because of cold-hammering of the coins during their manufacture. Such corrosion processes on massive copper alloy coins may produce features that may lead to their incorrect classification as subferrati, i.e. copper alloy coins with an iron core. Our results may help in future to distinguish strongly corroded massive coins from subferrati. Show less
The widespread use of private military and security companies (PMSCs) in United Nations peacebuilding missions often undermines the effectiveness of these missions. PMSCs tend to encourage, in... Show moreThe widespread use of private military and security companies (PMSCs) in United Nations peacebuilding missions often undermines the effectiveness of these missions. PMSCs tend to encourage, in unnecessary ways, what is called security risk management and promote the militarization of humanitarian efforts. They encourage humanitarian aid organizations to protect their personnel with barbed wire fences, security guards, armed convoys, and secure aid compounds, even if the security risks are relatively low. Consequently, these militarized humanitarian efforts heighten the perception of risks and intensify security measures, which create physical and psychological barriers between humanitarian aid personnel and the local communities in which they carry out their tasks. This situation undermines local ownership of peacebuilding efforts and makes them less responsive to the local communities involved in these efforts. This article provides a comparative analysis of the nature of this problem and its effects in the Global South. Show less
Claes, L.M.G.F.E.; Groot, T. de; Huisman, H.; Kort, J.W. de; Os, B. van 2021
Een artikel schrijven voor Bestuurskundige Berichten is niet de enige manier om invloed uit te oefenen binnen de vakgroep. Er zijn ook officiële organen met studenten in hun gelederen. Eén hiervan... Show moreEen artikel schrijven voor Bestuurskundige Berichten is niet de enige manier om invloed uit te oefenen binnen de vakgroep. Er zijn ook officiële organen met studenten in hun gelederen. Eén hiervan is de studierichtingscommissie en zij stelt zich hier voor. Show less
Naar aanleiding van de vele reakties, en dit is niet gelogen, op onze brief waarin wij verzoeken of jullie willen komen met vragen, problemen en of kritiek lijkt het ons juist jullie op de hoogte... Show moreNaar aanleiding van de vele reakties, en dit is niet gelogen, op onze brief waarin wij verzoeken of jullie willen komen met vragen, problemen en of kritiek lijkt het ons juist jullie op de hoogte te houden over de vorderingen op democratisch gebied binnen de vakgroep bestuurskunde. Ook willen we je in dit artikel informatie verschaffen over de plaats van de vakgroep bestuurskunde binnen de universiteit, de opbouw van de vakgroep en de problemen die spelen binnen onze vakgroep. Show less
