Development of Geopolymer Systems for High Temperature Applications

Geopolymers are amorphous, inorganic structures based on silicate and aluminate tetrahedrons and could be beneficial in thermal and fire resistant applications. The outcomes from this work suggest that fly ash geopolymer composites suitable for thermal applications can be produced. When compared to OPC based systems geopolymers showed extended thermal resistance (from 500 °C to 800 °C). Improved thermal properties were achieved with increases in compressive strength after firing to 1000 °C and the near elimination of expansive events at high temperature

Online Clinical Legal Education: Challenging the Traditional Model

It has been suggested that the “Digital Age provides an opportunity to revitalize and modernize legal education and to make it more individualized, relevant, human, and accessible”. Delivery of law degree programs fully online is one way the internet has begun to change, if not (yet) revolutionise, legal education in the twenty-first century.  In Australia, law students have been able to obtain their law degree online for a number of years.  Online clinical legal education, however, is still in its infancy.In this article, the authors argue that the greater use of technology in legal education is inevitable, and law schools offering degrees fully online will continue to increase, at least in Australia. The rewards and risks of online legal education are considered from the perspective of a law school in which over 80% of its 855 students study law fully online. The development and implementation of clinical opportunities for students studying online also is discussed.

A comparison between different foaming methods for the synthesis of light weight geopolymers

Foaming to reduce the density of geopolymeric materials is increasingly being reported in the literature as it has been shown to be effective in improving their insulating properties. However, there is no consistency in foaming methods and as such this study was performed to compare methods in order to better understand their effect on the properties of geopolymers. A surfactant and two chemical foaming agents (hydrogen peroxide and aluminium powder) were added to a fly ash based geopolymer matrix. Surfactant was also combined with each of the chemical foaming agents in order to stabilise the foam in the geopolymer matrix and to reduce coarse pores. The physical, mechanical and microstructural properties of the low density geopolymers are presented and the effects of the foaming agents’ characteristics on the hardened product is discussed, as well as the relative merits of the different procedures to synthesise the foamed geopolymer. It was found that homogeneous microstructures with small pores can be obtained by adding surfactant and hydrogen peroxide. The combination of hydrogen peroxide (0.1 wt%) and surfactant (1.0 wt%) produced geopolymer foams with density and compressive strength values of 0.94 g/cm3 and 4.6 MPa, respectively

In situ elevated temperature testing of fly ash based geopolymer composites

In situ elevated temperature investigations using fly ash based geopolymers filled with alumina aggregate were undertaken. Compressive strength and short term creep tests were carried out to determine the onset temperature of viscous flow. Fire testing using the standard cellulose curve was performed. Applying a load to the specimen as the temperature increased reduced the temperature at which viscous flow occurred (compared to test methods with no applied stress). Compressive strength increased at the elevated temperature and is attributed to viscous flow and sintering forming a more compact microstructure. The addition of alumina aggregate and reduction of water content reduced the thermal conductivity. This led to the earlier onset and shorter dehydration plateau duration times. However, crack formation was reduced and is attributed to smaller thermal gradients across the fire test specimen

New high-resolution age data from the Ediacaran-Cambrian boundary indicate rapid, ecologically driven onset of the Cambrian explosion

The replacement of the late Precambrian Ediacaran biota by morphologically disparate animals at the beginning of the Phanerozoic was a key event in the history of life on Earth, the mechanisms and the timescales of which are not entirely understood. A composite section in Namibia providing biostratigraphic and chemostratigraphic data bracketed by radiometric dating constrains the Ediacaran–Cambrian boundary to 538.6–538.8 Ma, more than 2 Ma younger than previously assumed. The U–Pb-CA-ID TIMS zircon ages demonstrate an ultrashort time frame for the LAD of the Ediacaran biota to the FAD of a complex, burrowing Phanerozoic biota represented by trace fossils to a 410 ka time window of 538.99±0.21 Ma to 538.58±0.19 Ma. The extremely short duration of the faunal transition from Ediacaran to Cambrian biota within less than 410 ka supports models of ecological cascades that followed the evolutionary breakthrough of increased mobility at the beginning of the Phanerozoic

STARD 2015: An Updated List of Essential Items for Reporting Diagnostic Accuracy Studies.

Incomplete reporting has been identified as a major source of avoidable waste in biomedical research. Essential information is often not provided in study reports, impeding the identification, critical appraisal, and replication of studies. To improve the quality of reporting of diagnostic accuracy studies, the Standards for Reporting of Diagnostic Accuracy Studies (STARD) statement was developed. Here we present STARD 2015, an updated list of 30 essential items that should be included in every report of a diagnostic accuracy study. This update incorporates recent evidence about sources of bias and variability in diagnostic accuracy and is intended to facilitate the use of STARD. As such, STARD 2015 may help to improve completeness and transparency in reporting of diagnostic accuracy studies

Performance of fibre reinforced, low density metakaolin geopolymers under simulated fire conditions

This paper presents a study on the thermal behaviour of metakaolin based geopolymers that have been foamed and fibre reinforced in order t1o assess their suitability for high temperature applications such as thermal barriers and fire resistant panels. An international standard fire curve (ISO 834, 1999) was used to simulate the heating conditions of a fire. Fire testing was conducted on 50 mm thick panels with an exposure size of 200 mm×200 mm. Fire ratings of more than one hour were achieved for all samples

Strategies to control the high temperature shrinkage of fly ash based geopolymers

Strategies to control thermally induced shrinkage in fly ash based geopolymers are investigated. The useof low (100 MPa). Wollastonite addition also improved the flexural strength of the samples which was attributed to its acicular shape imparting fibre-like qualities. Microstructural investigations showed that unfired samples predominantly consisted of spherical particles coated with reaction product. Firing to 1000 °C converted the morphology to a more compact phase with increased pore size

Présentation de la plénière d'ouverture : tendances internationales de l'enseignement post-obligatoire /

Titre de départ"Une conférence internationale par le Programme de l'OCDE pour la construction et l'équipement de l'éducation et le Ministère de l'éducation de la Province de Québec"En-tête du titre: Les locaux de l'enseignement professionnel et techniqu