61 research outputs found
A short historical overview on the use of lead
This historical introduction to the use of lead in art and technology was originally written to give context to lead conservation studies by the authors. The intention is to bring many rel- evant studies on lead together starting a discussion, which stresses that it was once impossi- ble to imagine a life without lead, and its alloys and compounds. Despite its environmental and health problems, lead remains ubiquitous even in modern technology for example in roofing, as an important component in low melting point or low friction alloys, in batteries and munitions
How to preserve lead artifacts for future generations
This paper discusses the advantages and disadvantages of different conservation treatments that have been developed over the years to protect the lead cultural heritage. The chemical and aesthetic points of view are looked at
Intergroup reconciliation between Flemings and Walloons : the predictive value of cognitive style, authoritarian ideology, and intergroup emotions
Testifying to the gap in fundamental research on positive intergroup outcomes, we investigated reconciliation attitudes in a non-violent intergroup context (i.e., the linguistic conflict in Belgium). By incorporating both important predictors of negative outgroup attitudes (i.e., individual differences in rigid cognitive styles and authoritarian ideologies), and important predictors of reconciliation (i.e., intergroup emotions), we aimed to contribute to a more comprehensive theoretical framework for the analysis of intergroup relations. We recruited one Flemish ('N' = 310) and one Walloon ('N' = 365) undergraduate students sample to test the proposed model. Structural equation analyses with maximum likelihood estimation were conducted using the Lavaan package. In both samples, similar patterns were found. More in particular, the need for cognitive closure appeared to be the basic predictor of right-wing attitudes (i.e., right-wing authoritarianism and social dominance orientation) and essentialist thinking, which were then associated with less outgroup empathy and trust, and more outgroup anger. Furthermore, outgroup trust and empathy were positively related to reconciliation. Interestingly, some differences between the Flemish and Walloon sample were found, such as the direct effects of need for closure and social dominance orientation in the first sample, and the non-significant effects of essentialism in the latter sample. Considering the ongoing public and political debate about the linguistic conflict in Belgium, these findings shed a new light on how individual differences relate to specific outgroup emotions, and how these are associated with important intergroup outcomes in the face of intergroup conflict
Effects of activated ceria and zirconia nanoparticles on the protective behaviour of silane coatings in chloride solutions
This work investigates the effect of CeO2 and ZrO2 nanoparticles on the corrosion protection performance of non-inhibited and cerium inhibited silane coatings in 3.5% and 5% NaCl solutions on electro-galvanized steel substrates. Atomic force microscopy (AFM) results show relatively uniform coating thickness and varying nanoparticle distribution depending on coating composition. The corrosion behaviour of the sol–gel coatings revealed that CeO2-ZrO2 nanoparticles reinforce the barrier properties of the silane films and seem to act as nano-reservoirs providing a prolonged release of cerium ions. This prolonged release of inhibitor from oxide nanoreservoirs confers longer protection to the metallic substrate
Towards a new method for coating heritage lead
Ethanolic solutions of long-chain carboxylic acids can be applied to lead metal substrates to form a coating of lead carboxylate which provides protection against atmospheric pollutants. In this paper we describe the optimal inhibitor concentration for the coating on lead. Electrochemical impedance data taken before and after immersion in media modelling oak emitted volatile organic compounds (VOCs) polluted atmospheres show that coating effectiveness decreases after exposure, but the effect is lessened if longer chain carboxylates are used
Sustainability effects of including concrete cracking and healing in service life prediction for marine environments
With today’s focus on sustainable design, it is necessary to adequately predict and prolong service life of concrete in marine environments. By introducing self-healing properties, service life extension can be achieved. However, in prediction models, the required concrete mix specific input is usually not available. Moreover, little attention goes to the unavoidable presence of cracks. Finally, autonomous crack healing has almost never been taken into account. In this paper, the relevant model input was estimated from experimental chloride profiles. It enabled an adequate prediction of the chloride-induced steel depassivation period for cracked and uncracked 15% fly ash concrete (8–104 years, respectively). Comparison with self-healing by means of encapsulated polyurethane indicated a 48–76% self-healing efficiency. It could extend the corrosion initiation period to 36–68 years. Being much less subject to time-dependent repair, PU based self-healing concrete has a 77–88% lower environmental impact than traditional (cracked) concrete
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