Abstract: A multilayer model of a single coated nanoparticle has been refined through finite elements method based simulations and resulted in a successful matching of the experimental UV–visible spectra of ligand-coated silver nanoparticles. The computational matching of the surface plasmon resonance (SPR) band reveals both a ligand-type dependence of the effective plasma frequency and a size dependence of the SPR damping effect within the modeled nanoparticle. The observed differences of effective plasma frequency between thiol and amine-coated nanoparticles are consistent with the already known stronger bonding of thiols on silver compared to amines.

Abstract: A series of water-soluble Au nanocrystals with different core sizes coated by either negatively or positively charged ligands are synthesized. We find a ligand interexchange process takes place when positively and negatively charged nanocrystals are mixed together and heated, resulting in mixed charged zwitterionic nanocrystals. The ligand exchange process between nanocrystals is studied in detail by electrophoresis...

Abstract: Long-term chemical and structural stability of an ion conducting ceramic is one of the main criteria for its selection as an electrolytic membrane in energy plant devices. Consequently, medium density SrZr0.9Er0.1O3-δ (SZE) anhydrous proton conducting ceramic – a potential electrolyte of SOFC/PCFC, was analysed by neutron diffraction between room temperature and 900°C...

Abstract: South Africa has in recent years gained increasing importance for our understanding of the evolution of 'modern human behaviour' during the Middle Stone Age (MSA). A key element in the suite of behaviours linked with modern humans is heat treatment of materials such as ochre for ritual purposes and stone prior to tool production. Until now, there has been no direct archaeological evidence for the exact procedure used in the heat treatment of silcrete.

Abstract: This paper reports on a molecular dynamics investigation of the molecular organization of alkanethiolates (from ethane to dodecanethiolate) on octahedral and cubic gold nanocrystals with diameters up to 10 nm. We show that the average surface per adsorbed thiolate only slightly depends on the nanocrystal shape and the alkane chain length. Two different organizations of thiolates are observed on the facet centers and edges of octahedral nanocrystals, while on cubic nanocrystals only one appears...

Abstract: The Kirkendall effect is a classical phenomenon in materials science, and it is referred to as a nonreciprocal interdiffusion process through an interface of two metals with strikingly different atomic diffusivities, leading to a formation of vacancies called Kirkendall voids. The nanoscale Kirkendall effect has been vastly applied in the fabrication of hollow nanostructures after the first report on the synthesis of Co-based hollow nanocrystals...

Twenty-one glazed red stoneware objects, with gilded or gold-painted decor from different collections (Cité de la Céramique, Sèvres, France; Art Institute of Chicago, USA; a private collection) attributed to 18 th century Böttger, Meissen (Saxony) have been analyzed with a portable X-ray fluorescence spectrometer (XRF) and portable or fixed Raman micro-spectrometer in laboratory/museum/collector rooms. Analysis was aimed at gaining a deeper understanding of the technology of production of the gilding and black glaze, to augment what is known from the limited literature. Three different techniques to obtain a golden décor emerged as a result of this study: i) a true gilding with gold, ii) gold with mercury, and iii) an alloy of copper and zinc.

Abstract: This study was carried out to elucidate the causes of irregularities and discolorations on the surface of parts of a weathering steel sculpture which had been in contact with wood pallets. Non-destructive analysis of the samples by Raman spectroscopy revealed the presence of iron oxalates and calcium oxalates. Thermodynamic modeling suggested that the detected oxalates were produced by the reaction of oxalic acid, a potential metabolite excreted by microorganisms, and elements present in the steel surface such as iron...

Abstract: During decades the use of gypsum in different buildings has been very common, especially in the Atlantic lands of Europe. Decay compounds like salt crystallizations are ones of the principal deterioration factors of such historical buildings. In this study, gypsum-based plasters from different inner rooms of the Igueldo Lighthouse (San Sebastian, Spain), a building dated back to 1860 that has been subjected to several repairs within these years, were investigated in order to ascertain the main mineral phases produced during the weathering process...

Abstract: The in situ generation of an anionic initiator X– obtained by the deprotonation of various secondary amides with tBuP4 phosphazene base was tested as possible way to initiate the polymerization of 1,2-epoxybutane. The initiation efficiency of different amide-containing molecules was investigated. Particular attention was given to the detection of eventual transfer or side reactions, especially due to nucleophilic attacks on the initiator moiety at the α-chain end. In all cases, the initiation of the polymerization by the amidate anion was effective. And in most cases, the polymerization proceeded in a controlled manner to afford amide end-capped poly(butylene oxide) with narrow molar mass distribution and expected molar masses.