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The UC Research Repository collects, stores and makes available original research from postgraduate students, researchers and academics based at the University of Canterbury.
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Recent Submissions
Shifting Perspectives in Polar Research: Global Lessons on the Barriers and Drivers for Securing Academic Careers in Natural Sciences
(Frontiers Media SA, 2021) Figuerola , Blanca; Valiente , Nicolas; Barbosa , Andres; Brasier , Madeleine J.; Colominas-Ciuró , Roger; Convey , Peter; Liggett , Daniela; Fernández-Martínez , Miguel Angel; Gonzalez , Sergi; Griffiths , Huw J.; Jawak , Shridhar D; Merican , Faradina; Noll , Daly; Prudencio , Janire; Quaglio , Fernanda; Pertierra , Luis R.
The polar regions provide valuable insights into the functioning of the Earth’s regulating systems. Conducting field research in such harsh and remote environments requires strong international cooperation, extended planning horizons, sizable budgets and long-term investment. Consequently, polar research is particularly vulnerable to societal and economic pressures during periods of austerity. The global financial crisis of 2008, and the ensuing decade of economic slowdown, have already adversely affected polar research, and the current COVID-19 pandemic has added further pressure. In this article we present the outcomes of a community survey that aimed to assess the main barriers and success factors identified by academic researchers at all career stages in response to these global crises. The survey results indicate that the primary barriers faced by polar early and mid-career researchers (EMCRs) act at institutional level, while mitigating factors are developed at individual and group levels. Later career scientists report pressure toward taking early retirement as a means of institutions saving money, reducing both academic leadership and the often unrecognized but vital mentor roles that many play. Gender and social inequalities are also perceived as important barriers. Reorganization of institutional operations and more effective strategies for long-term capacity building and retaining of talent, along with reduction in non-research duties shouldered by EMCRs, would make important contributions toward ensuring continued vitality and innovation in the polar research community.
Stress-density model validation: Free-field liquefaction analysis
(Elsevier BV, 2024) Zakerinia , Majid; Hayden , Connor P.; McGann, Christopher; Wotherspoon , Liam M.
Liquefaction has caused severe damage to buildings and infrastructure during numerous earthquakes, leading
researchers to develop constitutive models that can capture complex soil behaviour in liquefaction-induced
phenomena. Constitutive models require validation against laboratory or real-world data to assess their capa bility. This paper first discusses the recent implementation of the stress-density (S-D) model in the OpenSees
finite element platform. Subsequently, calibration and validation phases evaluate the performance of the S-D
model against two previously conducted centrifuge tests. Single-element simulations of cyclic simple shear tests
inform the parameter calibration for the Nevada sand, which comprises the two main layers in the centrifuge
tests. The validation phase consists of eight 1-D site response analyses in OpenSees compared to the centrifuge
tests in terms of accelerations, spectral accelerations, pore water pressures, and settlements. The current study
shows that the model reasonably predicts the soil behaviour in terms of acceleration and pore water pressure,
particularly in the liquefiable layer
Vibration Effect Produced by Raised Pavement Markers on the Exit Ramp of an Expressway
(Hindawi Limited, 2019) Liang , Guohua; Yin , Yujie; Zhang , Dong; Li , Rui; Wu , Yan; Li , Yu
Driving over raised pavement markers (RPMs) spaced at different spacing, the human body will experience different vibrations. To explore whether RPMs situated at the exit ramp of an expressway induce a good vibration warning effect, this paper determines the spacing of RPMs situated along a deceleration lane and curved ramp. Models of roads, vehicles, and RPMs are first established in the ADAMS software, after which an integrated human-chair model constructed in SolidWorks is imported into ADAMS, and then the complete model is formed so that vibration simulations of different types of vehicle at different spacing and speeds can be carried out. The results show that the vibration warning effects of the spacing proposed by the existing Chinese specifications and this paper are basically between level III and level IV, the driver’s subjective feeling is between less comfortable and uncomfortable, and both induce a good vibration warning effect. For a linear deceleration lane, when considering traffic safety, a spacing of 3 m is recommended; when considering the economy, a spacing of 6 m is recommended. For a curved deceleration lane and curved ramp, according to the actual curve radius, the spacing of RPMs can refer to the spacing recommended in the paper. In addition, the vibration warning effect for cars and semi-trailer trucks initially increases with an increase in the speed; then, after reaching a certain peak speed, the effect decreases with an increase in the speed, and finally, it tends to become gentle at speeds exceeding 100 km/h. The vibration warning effect for a semi-trailer truck is better than that for a car under the same spacing and speed.
A Study on the Calculation of Platform Sizes of Urban Rail Hub Stations Based on Passenger Behavior Characteristics
(Hindawi Limited, 2020) Zhang , Na; Chen , Feng; Zhu , Yadi; Peng , Hui; Wang , Jianpo; Li, Yu
The Chinese national rail transit design specification decides the size of urban rail transit platforms in China. This suggested method treats passengers as homogeneous individuals when calculating the walking area within a platform. However, the heterogeneity of passenger behavior in a rail hub station has not been considered. It is not reasonable to see passengers as homogeneous individuals. In this study, by observing passenger behavior characteristics at rail hub platforms, two parameters were obtained, walking speed and luggage size. Passengers were then accordingly put into different groups, and dynamic spatial demands for each passenger group were calculated by parameter fitting functions. Based on the theory of spatiotemporal consumption, the nonlinear constraint model was constructed to determine the space-time consumption of each passenger group, and finally the area demands of different types of passengers were obtained for different time and passenger flows. An application was made to Beikezhan Station on Xi’an Metro line 2. The calculation results show the area demands ranges of four passenger groups with distinct characteristics, and their space-time consumption varied. The study can calculate the space demands for all passenger varieties within a rail hub transit platform and provide suggestions for the determination of the ideal walking area size of rail transit platforms.
The effect of age on emotion processing in individuals with mood disorders and in healthy individuals
(Frontiers Media SA, 2024) Gray , Vanessa; Moot , William; Frampton , Christopher M. A.; Douglas , Katie M.; Gallagher , Peter; Jordan , Jennifer; Carter, Janet; Inder , Maree; Crowe , Marie; McIntosh, Virginia; Porter , Richard J.
Introduction: Emotion processing is an essential part of interpersonal relationships and social interactions. Changes in emotion processing have been found in both mood disorders and in aging, however, the interaction between such factors has yet to be examined in detail. This is of interest due to the contrary nature of the changes observed in existing research - a negativity bias in mood disorders versus a positivity effect with aging. It is also unclear how changes in non-emotional cognitive function with aging and in mood disorders, interact with these biases. Methods and results: In individuals with mood disorders and in healthy control participants, we examined emotional processing and its relationship to age in detail. Data sets from two studies examining facial expression recognition were pooled. In one study, 98 currently depressed individuals (either unipolar or bipolar) were compared with 61 healthy control participants, and in the other, 100 people with bipolar disorder (in various mood states) were tested on the same facial expression recognition task. Repeated measures analysis of variance was used to examine the effects of age and mood disorder diagnosis alongside interactions between individual emotion, age, and mood disorder diagnosis. A positivity effect was associated with increasing age which was evident irrespective of the presence of mood disorder or current mood episode. Discussion: Results suggest a positivity effect occurring at a relatively early age but with no evidence of a bias toward negative emotions in mood disorder or specifically, in depressed episodes. The positivity effect in emotional processing in aging appears to occur even within people with mood disorders. Further research is needed to understand how this fits with negative biases seen in previous studies in mood disorders.