Exploring a Multi‐modal Experimental Approach to Investigation of Local Embedment Behaviour of Wood under Steel Dowels

A multi‐modal experimental approach for analysing the embedment behaviour of timber connections with steel dowels is proposed in this study. In this approach, a standard mechanical embedment test on single‐dowel connections is combined with an optical measurement of surface deformations of the connection based on digital image correlation principle and an X‐ray micro‐computed tomography examination of the deformations in the dowel‐wood interface. The latter is conducted on cylindrical cores including the dowel hole, physically extracted from the loaded specimen at three characteristic points of the load‐deformation curves. The major challenge of this procedure is disrupted load transfer between the cylindrical core specimens and the external material they were plugged in for further analysis. Despite its challenges and limitations, the method revealed a potential for an unprecedented insight into the micromechanics of dowel connections and for effective correlation of the micro‐level observations with the external macroscopic load‐deformation characteristics.     

The strength of hybrid glass/carbon fibre composites

The tensile mechanical properties of hybrid composites fabricated from glass and carbon fibres in an epoxy matrix have been evaluated over a range of glass: carbon ratios and states of dispersion of the two phases. The failure strain of the carbon phase increased as the relative proportion of carbon fibre was decreased, and as the carbon fibre was more finely dispersed. This behaviour is commonly termed the hybrid effect, and failure strain enhancement of up to 50% has been measured. Only part of the effect may be attributed to internal compressive strains induced in the carbon phase by differential thermal contraction as the composite is cooled from its cure temperature. The laminae or ligaments of carbon fibre dispersed in the glass fibre phase show a multiple failure mode, and when the constitution is favourable catastrophic failure does not occur until a considerable number of ligament fractures have accumulated. Failure is thus progressive, and the material is effectively tougher than equivalent all-carbon fibre composites.     

DETERMINATION OF INFINITE DILUTION ACTIVITY COEFFICIENTS FOR ORGANIC-AQUEOUS SYSTEMS USING A DILUTE VAPOR-LIQUID EQUILIBRIUM METHOD

A low pressure vapor-liquid equilibrium apparatus has been developed, tested and verified for the measurements of dilute solution activity coefficients for different organic solutes in aqueous systems. Activity coefficient data were measured for aqueous binary mixtures involving methanol, acetone, and benzene at 25°C. The experimental measurements targeted the range of solute liquid compositions extending from the Gas Chromalograph detection limit to 0.3 mole fraction for methanol and acetone, and to the miscibility mole fraction for benzene. Precise extrapolation to determine the infinite dilution activity coefficients (γ_i^∞) was achieved. Instrumental, external and internal consistency tests performed on the acquired data indicate a good level of experimental consistency.     

Der Koordinatenoszillograph

Übersicht Durch den Koordinatenoszillographen wird die Aufgabe gelöst, in Lichtschrift den Zusammenhang zwischen zwei oder mehr Meßgrößen zu liefern, welche einzeln mit Oszillographenschleifen erfaßt werden.     

气泡城市

Spacebuster是个动态的充气结构，它是便携式、可拓展的场馆。设计旨在将各种公共空间转变为可以进行社交集会的场所。事实上，Spacebuster是Raumlabo健筑设计事务所对上一个项目Kuechenmonumenl的迭代创新，它使得曼哈顿和布鲁克林的春天大放异彩，承办了很多各种社交和公众活动。     

Modelling cadmium flows in Australia on the basis of a substance flow analysis

This paper, which is an extension of the Suphaphat Kwonpongsagoon’s PhD thesis (2006), investigates a stationary model designed to evaluate substance flows for a case study of cadmium (Cd) in Australia. It covers the mining industry, the production and use of goods for agriculture, construction and households as well as the environmental sectors of agriculture, surface water and landfills. The model is calibrated with Cd flow data obtained in a previous study. The results of the calibrated model are consistent with those of other studies from other countries. Possible measures and options to reduce the Cd flows to various environmental sectors are discussed by applying sensitivity analysis and parameter variations to the calibrated model. As “agriculture” was used to illustrate one of the most important processes discussed in this paper, the results show that the most effective measures are the reduction of the Cd content in fertilizers and of atmospheric Cd deposition. It is concluded that a mathematical model is very useful for understanding a system that is crucial for environmental management.     

Policies for the transition towards a hydrogen economy: the EU case

This paper reviews the current EU policy framework in view of its impact on hydrogen and fuel cell development. It screens EU energy policies, EU regulatory policies and EU spending policies. Key questions addressed are as follows: to what extent is the current policy framework conducive to hydrogen and fuel cell development? What barriers and inconsistencies can be identified? How can policies potentially promote hydrogen and fuel cells in Europe, taking into account the complex evolution of such a potentially disruptive technology? How should the EU policy framework be reformed in view of a strengthened and more coherent approach towards full deployment, taking into account recent technology-support activities?     

Evaluation of Osseointegration of Titanium Alloyed Implants Modified by Plasma Polymerization

By means of plasma polymerization, positively charged, nanometre-thin coatings can be applied to implant surfaces. The aim of the present study was to quantify the adhesion of human bone cells in vitro and to evaluate the bone ongrowth in vivo, on titanium surfaces modified by plasma polymer coatings. Different implant surface configurations were examined: titanium alloy (Ti6Al4V) coated with plasma-polymerized allylamine (PPAAm) and plasma-polymerized ethylenediamine (PPEDA) versus uncoated. Shear stress on human osteoblast-like MG-63 cells was investigated in vitro using a spinning disc device. Furthermore, bone-to-implant contact (BIC) was evaluated in vivo. Custom-made conical titanium implants were inserted at the medial tibia of female Sprague-Dawley rats. After a follow-up of six weeks, the BIC was determined by means of histomorphometry. The quantification of cell adhesion showed a significantly higher shear stress for MG-63 cells on PPAAm and PPEDA compared to uncoated Ti6Al4V. Uncoated titanium alloyed implants showed the lowest BIC (40.4%). Implants with PPAAm coating revealed a clear but not significant increase of the BIC (58.5%) and implants with PPEDA a significantly increased BIC (63.7%). In conclusion, plasma polymer coatings demonstrate enhanced cell adhesion and bone ongrowth compared to uncoated titanium surfaces.