Social capital and sustainability of urban environmental groups in Perth

Community based environmental groups have become an integral component of urban environmental stewardship initiatives in Perth metropolitan area. While the utility of Urban Environmental Groups (UEGs) has been recognized by several environmental policies and programs, the challenges of sustaining UEGs remain under-explored, especially, in Western Australia. This paper responds to this gap and explores the prospect of UEGs’ sustainability through the lens of social capital. The findings of a quantitative survey of 81 groups as well as qualitative observations suggest UEGs that are better at building and maintaining social capital are more likely to overcome resource-scarcities and sustain over time. Based on the findings, the paper views social capital as a necessary ingredient of sustainable community groups and discusses the strategic needs to support UEGs

Evaluating residential satisfaction with an innovative dual water supply system in water sensitive urban development

The Australian water industry is facing two major challenges: a rise in water demand due to a growing population and a decrease in rainfall availability due to a drying climate. This situation has triggered a re-evaluation of traditional water schemes and promoted consideration of alternatives for sustainable urban water management. One possibility is to replace drinking water usage in garden and outdoor irrigation with non-potable groundwater. This could save almost half of the water supplied in the residential sector, which is the biggest consumer of scheme water in most Australian cities. A major hurdle for the success of such fit-for-purpose groundwater schemes can be the lack of the resident’s participation and support. Currently there are uncertainties about the dynamic nature of individual’s attitudes in terms of satisfaction and accepting behaviours towards the fit-for-purpose water use. This can cause ambiguity in planning and implementation of such projects. The main purpose of this thesis is to address the following specific research questions: What are the factors that determine residential satisfaction with and behaviours towards the fit-for-purpose groundwater system? and What are the implications of such water system for community, water utilities and urban planners? These questions have been addressed through a quasi-experimental study utilizing two northern suburbs in Perth metropolitan: Ridgewood and “The Green”. “The Green” is selected as an experimental suburb and Ridgewood is selected as a control suburb, which is a standard metropolitan suburb having the usual main drinking water system. The use of non-drinking groundwater through the dual water supply system in “The Green” began in 2008 alongside the main water scheme. A broad spectrum of parallel literature from many disciplines was drawn upon to inform the research. Concurrent preliminary informal conversations with local residents and a number of field observations were helpful in refining and contextualising the research hypotheses regarding the determinants of residential satisfaction with the fit-for-purpose groundwater supply system in the context of water sensitive urban development. An exploratory mixed method approach was adopted starting with qualitative preliminary interviews with local residents to inform the development of a survey instrument. This was followed by the administration of the survey questionnaires at household level to collect quantitative data to measure the relationship among variables and test a model of residential satisfaction. The survey data and the secondary data about residential water consumption were analysed to develop a workable model for residential satisfaction with and behaviour towards the dual water supply system and water sensitive urban environment. Finally, qualitative information during stakeholder interviews, meetings, and seminars was used to interpret the planning implications of the model and behavioural responses towards the water system and urban development. The research results indicated that the majority of residents (70%) are satisfied with the nondrinking groundwater supply system in their home and neighbourhood. In “The Green”, the household drinking water consumption was reduced by 40% compared to the metropolitan average; however, excessive garden watering exemptions for new garden establishment caused 30% more water usage in “The Green” than the metropolitan average. This study found that the major components of residential environment satisfaction were the neighbourhood, neighbours, and home. Home satisfaction in “The Green” was determined mainly by home attributes and the garden satisfaction, which in turn was dependent upon garden attributes and satisfaction with the groundwater system. In this way, groundwater satisfaction had an indirect impact on home satisfaction mediated by garden satisfaction. The major determinants of groundwater satisfaction were: positive perceptions of operational issues, and risk of groundwater use (negative relationship), and preference for continuation of the groundwater system after its trial period. The major research findings are explained in Chapter Six, Seven, and Eight. The dynamic nature of community attitudes and community behaviours towards the fit-for-purpose water projects at urban settings were explored, and the planning and development consequences of the implementation of the alternative water systems were explained. The results of this study are highly applicable for water providers, urban planners, and community developers in promoting the successful implementation as well as improvement of fit-for-purpose water systems from a policy perspective. This thesis equally contributes to building knowledge and understanding of residential satisfaction and its relationship to innovative dual water systems in water sensitive urban environments. It facilitates the sustainable management and planning of urban water resources. The research also demonstrates the need to integrate general models of community satisfaction with specific water system attitudes to provide an indication of the role of water supply systems in the overall success of water sensitive developments

Development of sustainable biodegradable lignocellulosic hemp fiber/polycaprolactone biocomposites for light weight applications

Biocomposites with poly(ε-caprolactone) (PCL) as matrix and lignocellulosic hemp fiber with varying average aspect ratios (19, 26, 30 and 38) as reinforcement were prepared using twin extrusion process. The influence of fiber aspect ratio on the water absorption behavior and mechanical properties are investigated. The percentage of moisture uptake increased with the aspect ratio, following Fickian behavior. The hemp fiber/PCL biocomposites showed enhanced properties (tensile, flexural and low-velocity impact). The biocomposite with 26 aspect ratio showed the optimal properties, with flexural strength and modulus of 169% and 285% respectively, higher than those of neat PCL. However, a clear reduction on the mechanical properties was observed for water-immersed samples, with reduction in tensile and flexural moduli for the aspect ratio of 26 by 90% and 62%, respectively than those of dry samples. Summarily, the optimal sample provides an eco-friendly alternative to conventional, petroleum-based and non-renewable composites for various applications.Peer reviewedFinal Accepted Versio

Effectiveness of earthquake selection and scaling method in New Zealand

In New Zealand, time history analysis is either the required or preferred method of assessing seismic demands for torsionally sensitive and other important structures, but the criteria adopted for the selection of ground motion records and their scaling to generate the seismic demand remains a contentious and debatable issue. In this paper, the scaling method based on the least squares fit of response spectra between 0.4-1.3 times the structure's first mode period as stipulated in the New Zealand Standard for Structural Design Actions: Earthquake Actions (NZS1170.5) [1] is compared with the scaling methods in which ground motion records are scaled to match the peak ground acceleration (PGA) and spectral acceleration response at the natural period of the structure corresponding to the first mode with 5% of critical damping; i.e. Sa(TI, 5%). Incremental dynamic analysis (IDA) is used to measure the record-torecord randomness of structural response, which is also a measure of the efficiency of the intensity measure (IM) used. Comparison of the dispersions of IDA curves with the three different IMs; namely PGA, Sa(Ti, 5%) and NZS1170.5 based TM, shows that the NZS1170.5 scaling method is the most effective for a large suite of ground motions. Nevertheless, the use of only three randomly chosen ground motions as presently permitted by NZS1170.5 is found to give significantly low confidence in the predicted seismic demand. It is thus demonstrated that more records should be used to provide a robust estimate of likely seismic demand

Machine Learning-Based Prediction of Compressive Performance in Circular Concrete Columns Confined with FRP

This article presents a comprehensive investigation, focusing on the prediction and formulation of the design equation of compressive strength of circular concrete columns confined with Fiber Reinforced Polymer (FRP) using advanced machine learning models. Through an extensive analysis of 170 experimental data specimens, the study examines the effects of six key parameters, including concrete cylinder diameter, concrete cylinder-FRP thickness, compressive strength of concrete without FRP, initial compressive strain of concrete without FRP, elastic modulus and tensile strength of FRP, on the compressive strength of the circular concrete columns confined with FRP. The predictive model and design equation of compressive strength is developed using a machine learning technique, specifically the artificial neural networks (ANN) model. The results demonstrates strong correlations between the compressive strength of the circular concrete columns confined with FRP and certain factors, such as the compressive strength of the concrete and compressive strain of the concrete column without FRP, elastic modulus of FRP, and tensile strength of FRP. The ANN model specifically developed using Neural Designer, exhibits superior predictive accuracy compared to other constitutive models, showcasing its potential for practical implementation. The study's findings contribute valuable insights into accurately predicting the compressive performance of circular concrete columns confined with FRP, which can aid in optimizing and designing civil engineering structures for enhanced performance and efficiency

Effects of Row Spacings and Varieties on Grain Yield and Economics of Maize

Maize is the second most important crop of Nepal. The yield of the crop is low due to lack of appropriate plant density for the varieties. The field experiment was carried out to study the effect of different row spacings on different maize varieties at Deupur, Lamahi municipality of the dang district in province No. 5, Nepal during the rainy season from June to September, 2018. Four levels of spacings (boardcasting and three row spacings of 45, 60 and 75 cm) and two maize varieties (Rampur Composite and Arun-2) were evaluated using randomized complete block design with three replications. The highest grain yield was found in Rampur Composite and Arun-2 while they were planted with row spacing of 60 cm with plant to plant spacing of 25 cm. The highest grain yield, cob length, cob circumference, number of rows per cob, thousand grain weight  were reported when maize was planted in the  row spacing 60×25cm. Among the maize varieties, Rampur Composite produced the highest grain yield, cob length, cob circumference, number of rows per cob as compared to Arun-2. This study suggested that maize production can be maximized by cultivating maize varieties with row spacing of 60 cm with plant to plant spacing of 25 cm

Direct-write, focused ion beam-deposited,7 K superconducting C-Ga-O nanowire

We have fabricated C-Ga-O nanowires by gallium focused ion beam-induced deposition from the carbon-based precursor phenanthrene. The electrical conductivity of the nanowires is weakly temperature dependent below 300 K, and indicates a transition to a superconducting state below Tc = 7 K. We have measured the temperature dependence of the upper critical field Hc2(T), and estimate a zero temperature critical field of 8.8 T. The Tc of this material is approximately 40% higher than that of any other direct write nanowire, such as those based on C-W-Ga, expanding the possibility of fabricating direct-write nanostructures that superconduct above liquid helium temperaturesComment: Accepted for AP