The educational power of heritage sites

The aim of this article is to problematise the use of visits to heritage sites in history education in primary school. The empirical basis is a questionnaire and interviews with teachers in Sweden. Theoretically, the perspective is linked to the discussion of affective practices. The results show the connection that some, but not all, teachers recognise between different forms of historical knowledge. According to these teachers, visits to heritage sites activate the sensory experiences of the pupils, which has a positive impact on the pupils’ learning. Two ideal approaches can be discerned when it comes to the use of visits to heritage sites in history education. Such visits form either a teacher-driven, integral part of the education, or the teacher assigns the display of the site to local guides. The two approaches can be related to the history subject that appears in education, although this is ultimately determined by the educational setting

Geotechnical properties of Dublin boulder clay

Geotechnical characteristics of Dublin Boulder Clay (DBC) based on detailed site investigation and site experience from some recent large projects in Dublin are presented. This paper attempts to synthesise available information in parallel with recent work by Skipper et al (2005), who provide an updated understanding of the geology of the DBC. Having assessed the effects of sampling disturbance, the paper characterises the various formations and sub-units of the DBC. The interpreted material behaviour is related to observed engineering performance. It was found from the behaviour of earth retained structures that intact, clayey, DBC formations are 2 to 3 times stiffer than assessed from high quality laboratory tests on block samples. DBC is shown to be significantly stiffer than other well-characterised tills. Relatively inexpensive Multi Channel Surface Wave techniques (MASW) can give very reliable estimates of in situ small strain stiffness. High undrained triaxial compression strengths were measured and it appears that simple UU tests on high quality specimens give good results. Significant strength anisotropy was suggested by undrained triaxial extension strengths that were only 30% to 50% of the triaxial compression strengths. Field horizontal permeability values of the intact clayey till units have a representative mean of about 10-9 m/s and when compared to laboratory values suggest that the material may exhibit some degree of anisotropy of permeability. Overall, the measured engineering parameters for the DBC are favourable for many construction projects. Further work is required in order to understand the in situ horizontal stress profile and the stiffness anisotropy of the till. KEYWORDS: Glacial soils, In situ testing, laboratory tests, site investigation, strength, stiffness.Not applicabl

Optimization, Yield Studies and Morphology of WO₃Nano-Wires Synthesized by Laser Pyrolysis in C₂H₂and O₂Ambients—Validation of a New Growth Mechanism

<p>Abstract</p> <p>Laser pyrolysis has been used to synthesize WO₃nanostructures. Spherical nano-particles were obtained when acetylene was used to carry the precursor droplet, whereas thin films were obtained at high flow-rates of oxygen carrier gas. In both environments WO₃nano-wires appear only after thermal annealing of the as-deposited powders and films. Samples produced under oxygen carrier gas in the laser pyrolysis system gave a higher yield of WO₃nano-wires after annealing than the samples which were run under acetylene carrier gas. Alongside the targeted nano-wires, the acetylene-ran samples showed trace amounts of multi-walled carbon nano-tubes; such carbon nano-tubes are not seen in the oxygen-processed WO₃nano-wires. The solid&#8211;vapour&#8211;solid (SVS) mechanism [B. Mwakikunga et al., J. Nanosci. Nanotechnol., 2008] was found to be the possible mechanism that explains the manner of growth of the nano-wires. This model, based on the theory from basic statistical mechanics has herein been validated by length-diameter data for the produced WO₃nano-wires.</p