Designing for Online Collaborative Consumption: A Study of Sociotechnical Gaps and Social Capital

This study attempts to investigate sociotechnical gaps in online collaborative consumption (OCC) to improve user experience andprovide better design requirements. A new approach is proposed to evaluate usability and sociability of the OCC communities. The formation of social capital within OCC will also be studied to gain insights into design requirements. Due to its features as a community where OCC takes place, ETSY will be the focus of this study

Hexanuclear Iridium Clusters Supported on Magnesium Oxide

[Ir4(C0)12o] n the surface of MgO reacts to give [HIr4(CO)ll]-,w hich upon treatment with co at 200 OC gives [Ir6(C0)15]2- on the surface in high yield. Treatment of the latter with a solution of [PPN][CI] leads to extraction of [Ir6(C0)15]2b-y cation metathesis. The surface-bound [Ir6(CO)15]2w- as characterized by extended X-ray absorption fine structure (EXAFS) sk :e icnt rcolsocsoep ayg,r weeimthe tnhte w diatht at hined piucabtliinshge adn c rayvsetraalgloeg Irra-plrh icc odoartad ifnoart itohnis naunmiobne rin o tfh 4e. 1so alindd s taant ea.v Terhaeg er eIarc-Itrio ndsi sotfa nthcee iorfi d2iu.7m7 carbonyls on the basic MgO surface closely parallel those of iridium carbonyl anions in basic solutions. Treatment of the MgO-supported [h6(CO)IS]2- in He followed by H2 at 300 OC gives decarbonylated surface species shown by EXAFS spectroscopy to have iridium cluster frames substantially unchanged from those of the carbonyl anion precursor. The decarbonylated iridium clusters are among the most nearly uniform supported metals

Structure and Nature of the Metal-Support Interface: Characterization of Iridium Clusters on Magnesium Oxide by Extended X-Ray Absorption Fine Structure Spectroscopy.

X-ray absorption spectroscopy was used to characterize the metal-support interface in catalysts consisting of very small Ir clusters of nearly uniform nuclearity on the surface of MgO powder. [Ir4(CO)12] on MgO was converted in high yield into [HIr4(CO)11]- and separately into [Ir6(CO)15l2-. Extended X-ray absorption fine structure (EXAFS) data are consistent with the hypothesis that each cluster retained its nuclearity upon decarbonylation. The average Ir-Ir coordination in Ir,/MgO is 2.6 neighbors at a distance of 2.72 A, and the structure is modeled as a mixture of 40-50% tetrahedra and the remainder four-atom rafts on MgO. The average Ir-Ir coordination in Ir6/MgO is 2.7 neighbors at a distance of 2.12 A, and the structure is modeled as a mixture of about 25% Ir6 octahedra and the remainder Ir rafts on MgO. Another sample was treated in H2 at 623 K to give a typical supported metal catalyst having a distribution of Ir clusters averaging 10 8, in diameter. The Ir-support interfaces in Ir4/MgO and Irb/MgO are characterized by single Ir-Mg coordinations at 1.6 A and fourfold Ir-O coordinations at 2.6 A; the interface It atoms are suggested to be atop Mg ions in the (100) faces of MgO. However, this structural model is simplified, and the Ir-Mg interactions are not fully understood. The results demonstrate that the structurally simple supported Ir clusters are among the simplest supported metals; the metal-oxygen distances of approximately 2.6 Aare quite generally characteristic of metal particles and clusters supported on metal oxides and zeolites; the long distance is attributed to metal atoms interacting with oxygen of the support with hydrogen present at the interface

Avaliação do potencial de utilização da madeira de Schizolobium amazonicum "Paricá" e Cecropia hololeuca "Embaúba" para produção de painéis aglomerados Evaluation of potential use of the wood of Schizolobium amazonicum "Paricá" and Cecropia hololeuca "Embaúba" to particleboard manufacture

Esta pesquisa teve por objetivo avaliar o potencial de utilização de madeira de Schizolobium amazonicum (Paricá) e Cecropia hololeuca (Embaúba) para produção de painéis aglomerados. Foram produzidos painéis experimentais com densidade nominal de 0,70 g/cm³, utilizando a resina uréia-formaldeído e partículas de madeira de Paricá e Embaúba, e mistura destas, em proporções de 75, 50 e 25%. A madeira de Pinus taeda foi utilizada como testemunha. Os painéis foram prensados com pressão específica de 40 kgf/cm², temperatura de 160ºC e tempo de prensagem de 8 minutos. Os resultados das avaliações de propriedades de absorção de água, inchamento em espessura, ligação interna, módulo de elasticidade e módulo de ruptura, indicaram que as madeiras de Schizolobium amazonicum (Paricá) e Cecropia hololeuca (Embaúba) são tecnicamente viáveis para produção de painéis aglomerados.<br>This research was developed to evaluate the potential use of the woods Schizolobium amazonicum (Paricá) and Cecropia hololeuca (Embaúba) for manufacturing particleboard. Were made panels with the densities of 0.70 g/cm³, using mixtures of urea-formaldehyde resin and wood particles of Paricá and Embaúba, in proportions of 75, 50 and 25%. The Pinus taeda wood was used as the reference. The panels were pressed at the temperature of 160ºC, pressure of 40 kgf/cm², for 8 minutes. The evaluations of the properties of water absorption, thickness swelling, internal bond, modulus of elasticity and modulus of ruptures, showed that the woods of Schizolobium amazonicum (Paricá) e Cecropia hololeuca (Embaúba) are technically feasible for particleboard manufacture