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Yildirim T.,University of Wollongong | Ghayesh M.H.,University of AdelaideSouth Australia | Li W.,University of Wollongong | Alici G.,University of Wollongong
Energy Conversion and Management | Year: 2016

An energy harvester has been designed, fabricated and tested based on the nonlinear dynamical response of a parametrically excited clamped-clamped beam with a central point-mass; magnets have been used as the central point-mass which pass through a coil when parametrically excited. Experiments have been conducted for the energy harvester when the system is excited (i) harmonically near the primary resonance; (ii) harmonically near the principal parametric resonance; (iii) by means of a non-smooth periodic excitation. An electrodynamic shaker was used to parametrically excite the system and the corresponding displacement of the magnet and output voltages of the coil were measured. It has been shown that the system displays linear behaviour at the primary resonance; however, at the principal parametric resonance, the motion characteristic of the magnet substantially changed displaying a strong softening-type nonlinearity. Theoretical simulations have also been conducted in order to verify the experimental results; the comparison between theory and experiment were within very good agreement of each other. The energy harvester developed in this paper is capable of harvesting energy close to the primary resonance as well as the principal parametric resonance; the frequency-band has been broadened significantly mainly due to the nonlinear effects as well as the parametric excitation. © 2016

Afroughsabet V.,Polytechnic of Milan | Ozbakkaloglu T.,University of AdelaideSouth Australia
Construction and Building Materials | Year: 2015

This study investigates the effect of the addition of steel and polypropylene fibers on the mechanical and some durability properties of high-strength concrete (HSC). Hooked-end steel fibers with a 60-mm length were used at four different fiber volume fractions of 0.25%, 0.50%, 0.75%, and 1.0%. Polypropylene fibers with a 12-mm length were used at the content of 0.15%, 0.30%, and 0.45%. Some mixtures were produced with the combination of steel and polypropylene fibers at a total fiber volume fraction of 1.0% by volume of concrete, in order to study the effect of fiber hybridization. All the fiber-reinforced concretes contained 10% silica fume as a cement replacement. The compressive strength, splitting tensile strength, flexural strength, electrical resistivity, and water absorption of the concrete mixes were examined. Results of the experimental study indicate that addition of silica fume improves both mechanical and durability properties of plain concrete. The results also indicate that incorporation of steel and polypropylene fibers improved the mechanical properties of HSC at each volume fraction considered in this study. Furthermore, it was observed that the addition of 1% steel fiber significantly enhanced the splitting tensile strength and flexural strength of concrete. Among different combinations of steel and polypropylene fibers investigated, the best performance was attained by a mixture that contained 0.85% steel and 0.15% polypropylene fiber. Finally, the results show that introducing fibers to concrete resulted in a decrease in water absorption and, depending on the type of fibers, significant or slight reduction in the electrical resistivity of concrete compared to those of the companion plain concrete. ©2015 Elsevier Ltd. All rights reserved.

He X.-F.,China University of Geosciences | He X.-F.,University of AdelaideSouth Australia | Santosh M.,China University of Geosciences | Santosh M.,University of AdelaideSouth Australia | And 5 more authors.
Lithos | Year: 2016

Among the various Precambrian crustal blocks in the North China Craton (NCC), the geology and evolution of the Ordos Block remain largely enigmatic due to paucity of outcrop. Here we investigate granulite-facies metapelites obtained from deep-penetrating drill holes in the Ordos Block and report petrology, calculated phase equilibria and in-situ monazite LA-ICP-MS geochronology. The rocks we studied are two samples of cordierite-bearing garnet–sillimanite–biotite metapelitic gneisses and one graphite-bearing, two-mica granitic gneiss. The peak metamorphic age from LA-ICP-MS dating of monazite in all three samples is in the range of 1930–1940 Ma. The (U + Pb)–Th chemical ages through EPMA dating reveals that monazite occurring as inclusions in garnet are older than those in the matrix. Calculated metamorphic phase diagrams for the cordierite-bearing metapelite suggest peak P–T conditions ca. 7–9 kbar and 775–825 °C, followed by decompression and evolution along a clockwise P–T path. Our petrologic and age data are consistent with those reported from the Khondalite Belt in the Inner Mongolia Suture Zone in the northern part of the Ordos Block, suggesting that these granulite-facies metasediments represent the largest Paleoproterozoic accretionary belt in the NCC. © 2016 Elsevier B.V.

Peacock A.,University of New South Wales | Peacock A.,University of TasmaniaTasmania | Bruno R.,University of New South Wales | Bruno R.,University of TasmaniaTasmania | And 6 more authors.
Drug and Alcohol Dependence | Year: 2016

Objective The aims were to determine: (i) quantity and frequency of same-day use of opioids with benzodiazepines and/or alcohol amongst people who regularly tamper with pharmaceutical opioids; and (ii) socio-demographic, mental health, harms and treatment profile associated with same-day use of high doses. Method The cohort (n = 437) completed a retrospective 7-day diary detailing opioid, benzodiazepine, and alcohol intake. Oral morphine equivalent (OME) units and diazepam equivalent units (DEU) were calculated, with >200 mg OME, >40 mg DEU and >4 standard alcoholic drinks (each 10 g alcohol) considered a “high dose”. Results One-half (47%) exclusively consumed opioids without benzodiazepines/alcohol; 26% had days of opioid use with and without benzodiazepines/alcohol; and 26% always used opioids and benzodiazepines/alcohol. Same-day use of opioids with benzodiazepines/alcohol typically occurred on 1–3 days in the past week. Six in ten (61%) participants reported high dose opioid use on at least one day; one in five (20%) reported high dose opioid and high dose benzodiazepine/alcohol use on at least one day. The latter group were more likely to use prescribed opioid substitution therapy, often alongside diverted pharmaceutical opioids. Socio-demographic and clinical profiles did not vary according to high dose opioid, alcohol and benzodiazepine use, and there was no association with harms. Conclusions Same-day use of opioids with benzodiazepines/alcohol, and high dose combinations, are common amongst people who tamper with pharmaceutical opioids. Assessment of concomitant benzodiazepine/alcohol use during opioid therapy, implementation of real-time prescription monitoring systems, and research to clarify upper safe limits for polydrug depressant use, are potential implications. © 2016 Elsevier Ireland Ltd

He Z.,University of AdelaideSouth Australia | Kotousov A.,University of AdelaideSouth Australia | Fanciulli A.,University of AdelaideSouth Australia | Fanciulli A.,University of Padua | And 2 more authors.
International Journal of Solids and Structures | Year: 2016

Three-dimensional effects near crack front were subject of many analytical, numerical and experimental studies over the past 50 years. These studies were facilitated by obvious discrepancies between experimental evidences and predictions of two-dimensional theories of elasticity, which singular solutions currently form through a framework of contemporary Fracture Mechanics. In particular, the classical plane solutions of the theory of elasticity fail to describe the displacement, stress and strain fields in the close vicinity of the crack tip. Subsequently, the existing experimental techniques for determining stress intensity factor fully rely on the measurements taken outside the region affected by the three-dimensional effects, and, in particular, by 3D corner (vertex) singularity. In the present paper, we attempt for the first time to develop and validate an experimental procedure for accurate evaluation of mode I stress intensity factor from surface measurements of the transverse (out-of-plane) displacements over the area encapsulating the crack tip with a radius less than five per cent of the plate thickness. The proposed procedure can have several advantages in comparison with the existing experimental techniques. These are discussed in the paper. © 2015 Elsevier Ltd.

Wang B.,University of AdelaideSouth Australia | Wang B.,Womens and Childrens HospitalSouth Australia | Giles L.,University of AdelaideSouth Australia | Afzali H.H.A.,University of AdelaideSouth Australia | And 5 more authors.
Vaccine | Year: 2016

Introduction There is limited knowledge of adolescent views and attitudes towards immunisation. Our study investigated adolescent attitudes to immunisation and compared differences in vaccination attitudes between adolescents and adults. Methods This study was a cross-sectional, national online survey. Recruitment was stratified by state and gender to ensure findings were nationally representative. Regression analyses were performed to assess and compare adolescent and adult views on vaccine benefits, community protection, risks, side effects, sources of information, and decision-making preference. Results In 2013, 502 adolescents and 2003 adults completed the online survey. Lower levels of vaccine confidence were observed in adolescents with adolescents less likely to believe vaccines are beneficial and/or safe compared to adults (p = 0.043). Compared to females, males were less confident of vaccine benefits (p < 0.05) but less concern about vaccine side effects (p < 0.05). Adolescents were more concerned about vaccine side effects than adults for pain (p < 0.001), redness or swelling (p < 0.001), and fever (p = 0.006). Adolescents were less likely than adults to consider health professionals (p < 0.001) and the media (e.g. internet) (p = 0.010) as important sources of information, and were more likely to seek information from social networks (p < 0.001) including families and schools. Although 62.0% of adolescents agreed that parents should make the decision about vaccination for them, adolescents were more likely to prefer a joint decision with parents (p < 0.001) or by themselves (p = 0.007) compared with adults. Conclusion Adolescents have a lesser understanding of vaccine safety and benefits than adults and have higher concerns about potential vaccine reactions. Improving adolescent awareness and knowledge of the benefits and risks of vaccination through school-based educational programs may improve confidence in and uptake of vaccines for adolescents and increase vaccine confidence in the next generation of parents. © 2016 Elsevier Ltd

Hodyl N.A.,University of AdelaideSouth Australia | Hodyl N.A.,Womens and Childrens Hospital | Crawford T.M.,University of AdelaideSouth Australia | McKerracher L.,Womens and Childrens Hospital | And 4 more authors.
Early Human Development | Year: 2016

Background Neurotrophins are proteins critically involved in neural growth, survival and differentiation, and therefore important for fetal brain development. Reduced cord blood neurotrophins have been observed in very preterm infants (< 32 weeks gestation) who subsequently develop brain injury. Antenatal steroid exposure can alter neurotrophin concentrations, yet studies to date have not examined whether this occurs in the late preterm infant (33–36 weeks gestation), despite increasing recognition of subtle neurodevelopmental deficits in this population. Aim To assess the impact of antenatal steroids on cord blood neurotrophins in late preterm infants following antenatal steroid exposure. Study design Retrospective analysis. Subjects Late preterm infants (33–36 weeks; n = 119) and term infants (37–41 weeks; n = 129) born at the Women's and Children's Hospital, Adelaide. Outcome measures Cord blood neurotrophin-3 (NT-3), NT-4, nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) concentrations measured by ELISA. Results Cord blood NT-4 and NGF were increased at term compared to the late preterm period (p < 0.001), while BDNF and NT-3 were not different. In the late preterm period, cord blood NT-3 was reduced when antenatal steroids were administered > 24 h prior to delivery (p < 0.01). Conclusion This study identified an association between reduced cord blood NT-3 and antenatal steroid exposure in the late preterm period. The reduced NT-3 may be a consequence of steroids inducing neuronal apoptosis, thereby reducing endogenous neuronal NT3 production, or be an action of steroids on other maternal or fetal NT-3 producing cells, which may then affect neuronal growth, differentiation and survival. Regardless of the specific mechanism, a reduction in NT-3 may have long term implications for child neurodevelopment, and emphasizes the ongoing vulnerability of the fetal brain across the full preterm period. © 2016 Elsevier Ireland Ltd

Liu Y.,University of AdelaideSouth Australia | Wang T.,University of The Sunshine Coast | Calabrese A.N.,University of AdelaideSouth Australia | Carver J.A.,Australian National University | And 2 more authors.
Peptides | Year: 2015

The amphibian host-defense peptide caerin 1.8 [1GLFKVLGSV10AKHLLPHVVP20VIAEKL(NH2)] inhibits fibril formation of amyloid β 1-42 [1DAEFRHDSG10YEVHHQKLVF20FAEDVGSNKG30AIIGLMVGGV40VIA] [Aβ42] (the major precursor of the extracellular fibrillar deposits of Alzheimer's disease). Some truncated forms of caerin 1.8 also inhibit fibril formation of Aβ42. For example, caerin 1.8 (1-13) [1GLFKVLGSV10AKHL(NH2) and caerin 1.8 (22-25) [KVLGSV10AKHLLPHVVP20VIAEKL(NH2)] show 85% and 75% respectively of the inhibition activity of the parent caerin 1.8. The synthetic peptide KLVFFKKKKKK is a known inhibitor of Aβ42 fibril formation, and was used as a standard in this study. Caerin 1.8 is the more effective fibril inhibitor. IC50 values (±15%) are caerin 1.8 (75 μM) and KLVFFKKKKKK (370 μM). MALDI mass spectrometry shows the presence of a small peak corresponding to a protonated 1:1 adduct [caerin 1.8/Aβ42]H+. Molecular dynamics simulation suggests that both hydrogen bonding and hydrophobic interactions between Aβ42 and caerin 1.8 facilitate the formation of a 1:1 complex in water. Fibril formation from Aβ42 has been proposed to be based around the 16KLVF20F region of Aβ42; this region in the 1:1 complex is partially blocked from attachment of a further molecule of Aβ42. © 2015 Published by Elsevier Inc.

Hudson R.J.,University of AdelaideSouth Australia | Falcinella A.,University of AdelaideSouth Australia | Metha G.F.,University of AdelaideSouth Australia
Chemical Physics | Year: 2016

Titanium oxide and gold-titanium oxide clusters of stoichiometry MxOy (Mx = Ti3, Ti4 & AuTi3; y = 0 − (2x + 2)) have been investigated using density functional theory. Geometries of determined global energy minimum structures are reported and other isomers predicted up to 0.5 eV higher in energy. The Ti3On geometries build upon a triangular Ti3 motif, while Ti4On stoichiometries template upon a pseudo-tetrahedral Ti4 structure. Addition of a gold atom to the Ti3On series does not significantly alter the cluster geometry, with the gold atom preferentially binding to titanium atoms over oxygen atoms. Adiabatic ionization energies, electron affinities and HOMO/LUMO energies increase in magnitude with increasing oxygenation. The HOMO-LUMO energy gaps reach the bulk anatase band gap energy at stoichiometry (Au)TimO2m−1, and increase above this upon further oxygen addition. The most stable structural moieties are found to be a cage-like, C3v symmetric Ti4O6/7 geometry and a Ti3O6 structure with an η3-bound oxygen atom. © 2016

Mo K.H.,University of Malaya | Visintin P.,University of AdelaideSouth Australia | Alengaram U.J.,University of Malaya | Jumaat M.Z.,University of Malaya
Engineering Structures | Year: 2016

This paper presents the investigation on the local bond stress-slip behaviour of lightweight oil palm shell concrete (OPSC). The bond properties of the OPSC specimen with varying reinforcing bar diameters (12 and 16 mm), concrete cover sizes (50, 75 and 100 mm) and compressive strengths (25 and 35 MPa) were explored. A concrete cover size to reinforcing bar diameter (C/D) ratio of more than 4.17 resulted in pull-out failure while the ratio of 3.13 caused splitting cracks in the OPSC specimens. The reinforcing bar diameter, concrete cover size and compressive strength affected the normalized bond strength, provided that the splitting failure occurred in the concrete specimens. The proposed bond model for splitting failure incorporating the C/D ratio used in the closed-form solution for prediction of the serviceability crack width was found to give good estimation of the experimental results obtained from the full-scale beam tests. © 2016 Elsevier Ltd

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