title: The effect of silane coupling agent on iron sand for use in magnetorheological elastomers Part 1: Surface chemical modification and characterization

authors: Pickering, Kim L.

subjects: Science & Technology

abstract: Bis-(3-triethoxysilylpropyl) tetrasulphane (TESPT) was employed for surface modification of iron sand for use in magnetorheological elastomers (MREs). The amount of TESPT was varied at five levels (2, 4, 6, 8 and 10 wt%) relative to iron sand content to assess the optimum amount of coupling agent for interfacial bonding and damping performance. Evidence that coupling had occurred between iron sand and TESPT was identified by Raman Spectroscopy and the grafting percentage was determined by thermogravimetric analysis. Subsequently, isotropic MREs containing unmodified and modified iron sand particles and natural rubber were prepared. Crosslink density assessment by swelling testing provided evidence that the tetrasulphane group of TESPT formed crosslinks with the rubber chains. The results exhibited the advantages of TESPT as a coupling agent between iron sand particles and rubber and also revealed that 6% TESPT content produced the highest crosslink density. The effects of the amount of TESPT on dynamic mechanical properties the morphological characteristics of the MREs were also investigated.

text: The effect of silane coupling agent on iron sand for use in magnetorheological elastomers Part 1: Surface chemical modification and characterization Bis-(3-triethoxysilylpropyl) tetrasulphane (TESPT) was employed for surface modification of iron sand for use in magnetorheological elastomers (MREs). The amount of TESPT was varied at five levels (2, 4, 6, 8 and 10 wt%) relative to iron sand content to assess the optimum amount of coupling agent for interfacial bonding and damping performance. Evidence that coupling had occurred between iron sand and TESPT was identified by Raman Spectroscopy and the grafting percentage was determined by thermogravimetric analysis. Subsequently, isotropic MREs containing unmodified and modified iron sand particles and natural rubber were prepared. Crosslink density assessment by swelling testing provided evidence that the tetrasulphane group of TESPT formed crosslinks with the rubber chains. The results exhibited the advantages of TESPT as a coupling agent between iron sand particles and rubber and also revealed that 6% TESPT content produced the highest crosslink density. The effects of the amount of TESPT on dynamic mechanical properties the morphological characteristics of the MREs were also investigated.

year: 2015-01-01

title: Wegerif's 21st century advance on dialogic space [Review of Dialogic: Education for the Internet age by Wegerif, R]

authors: White, Elizabeth Jayne

abstract: Book review for Dialogic Pedagogy Journal: Wegerif, R. (2013). Dialogic: Education for the Internet age, London, Routledge.

text: Wegerif's 21st century advance on dialogic space [Review of Dialogic: Education for the Internet age by Wegerif, R] Book review for Dialogic Pedagogy Journal: Wegerif, R. (2013). Dialogic: Education for the Internet age, London, Routledge.

year: 2013

title: The first accurate and precise calendar dating of New Zealand Māori Pā, using Otāhau Pā as a case study.

authors: Hogg, Alan G.

subjects: Māori pā

abstract: This research investigates the potential of radiocarbon wiggle-match dating of palisade posts to provide precise and accurate calendar ages for Māori pā (forts), using Otāhau Pā in the inland Waikato region, New Zealand, as a case study. Even though pā are a dominant element of the pre-European North Island archaeological landscape, they are poorly understood archaeologically, with systematic investigations hampered by the relative lack of precision in radiocarbon dating within the context of New Zealand’s comparatively short prehistory. Using the Southern Hemisphere calibration curve SHCal13, we determine wiggle-match calibrated ages for three palisade posts, using different sampling resolutions to determine the cost- effectiveness of the method. We also test the accuracy of the wiggle-match by obtaining new Southern Hemisphere calibration data from known calendar-age kauri.

text: The first accurate and precise calendar dating of New Zealand Māori Pā, using Otāhau Pā as a case study. This research investigates the potential of radiocarbon wiggle-match dating of palisade posts to provide precise and accurate calendar ages for Māori pā (forts), using Otāhau Pā in the inland Waikato region, New Zealand, as a case study. Even though pā are a dominant element of the pre-European North Island archaeological landscape, they are poorly understood archaeologically, with systematic investigations hampered by the relative lack of precision in radiocarbon dating within the context of New Zealand’s comparatively short prehistory. Using the Southern Hemisphere calibration curve SHCal13, we determine wiggle-match calibrated ages for three palisade posts, using different sampling resolutions to determine the cost- effectiveness of the method. We also test the accuracy of the wiggle-match by obtaining new Southern Hemisphere calibration data from known calendar-age kauri.

year: 2017