Application of scanning tunnelling microscopy to the quality control of tungsten carbide (WC-Co) ball bearings

Scanning tunnelling microscopy (STM) has been applied to the topographical study of tungsten carbide (with 6% Co) ball bearings in air. It is shown that, for this material, scanning tunnelling microscopy can provide not only general topographical information on the surface microtexture with a resolution of nearly 0.1 nm if required, but also quantitative information for the measurement of surface roughness. Thus, scanning tunnelling microscopy has utility as a quality control tool of particular relevance in the submicron range. The STM topographical results from specific tungsten carbide ball bearings are presented, and the limitations and applicability of the STM technique when used as a quality control tool are discussed.     

Forming an intention to act on recommendations given via online social networks

Online social networks (OSN) are technology-enabled relationship tools in which a user creates a profile, connects to other individuals, and shares user-generated content with them. One of the many features OSN offer is the ability to post messages in the form of product and service recommendations. Although word-of-mouth research has examined this type of personal communication to intentionally influence consumer decisions, limited understanding exists regarding when a user acts upon a recommendation received from one of their contacts. In this study, we draw on relationship theories and research on trust to analyze the impact relationship characteristics and behaviors of the OSN contacts have on trust in the recommendation that subsequently leads a user to act on this OSN contact’s recommendation. The results of a survey of 116 OSN users showed that closeness, excessive posting behavior, and past recommendation experience have a positive impact on trust and intention to act on the recommendation. One characteristic of the relationships, that is, similarity, however, does not affect recommendation trust in the context of OSN. The findings enhance our understanding of relationships and their defining characteristics in OSN. The results also provide insights into how companies might leverage OSN in their marketing efforts.     

Psychometric Evaluation of the EMO and the SUS in the Context of a Large-Sample Unmoderated Usability Study

This article describes the psychometric properties of the Emotional Metric Outcomes (EMO) questionnaire and the System Usability Scale (SUS) using data collected as part of a large-sample unmoderated usability study (n = 471). The EMO is a concise multifactor standardized questionnaire that provides an assessment of transaction-driven personal and relationship emotional outcomes, both positive and negative. The SUS is a well-known standardized usability questionnaire designed to assess perceived usability. In previous research, psychometric evaluation using data from a series of online surveys showed that the EMO and its component scales had high reliability and concurrent validity with loyalty and overall experience metrics but did not find the expected four-factor structure. Previous structural analyses of the SUS have had mixed results. Analysis of the EMO data from the usability study revealed the expected four-factor structure. The factor structure of the SUS appeared to be driven by item tone. The estimated reliability of the SUS (.90) was consistent with previous estimates. The EMO and its subscales were also quite reliable, with the estimates of reliability for the various EMO scales ranging from .86 to .96. Regression analysis using SUS, EMO, and Effort as predictors revealed different key drivers for the outcome metrics of Satisfaction and Likelihood-to-Recommend. The key recommendations are to include the EMO as part of the battery of poststudy standardized questionnaires, along with the SUS (or similar questionnaire), but to be cautious in reporting SUS subscales such as Usable and Learnable.     

Security through diversity: moving from rhetoric to practice

In response to a range of contemporary urban water challenges, there is an increasingly urgent need to change the way water is used in our cities. In Australia, the 'Security through Diversity' policy has been introduced in a number of cities to help facilitate a shift towards sustainable urban water management. This qualitative case study research investigated the interpretation and implementation of this radically different urban water policy approach across the case study cities of Perth and Melbourne. To focus the research and allow for more reliable comparative analysis across the cities, the introduction of desalination and permanent water saving rules as new initiatives in these cities were of particular interest. The research results are drawn from a synthesis of over 65 semi-structured interviews with senior urban water practitioners in the case study cities, and a content analysis of key policy and guidance documents, as well as organizational literature where available. The key finding of this research was that because of an entrenched technological paradigm, and the difficulty in breaking this pattern of lock-in, practitioners are currently interpreting and implementing Security through Diversity in a way that does not fully realise the potential of this strategy. More specifically the interview results revealed that the urban water practitioner community believed that the introduction of seawater desalination would discharge their city's responsibility for achieving Security through Diversity and that demand management initiatives, while nice, are not essential to this policy position. Interestingly, despite context evidence to the contrary, the practitioners believed supply and demand planning to be an integrated practice within their city. The paper concludes by offering some recommendations to facilitate a more comprehensive implementation of Security through Diversity and outlines areas for possible future research.     

Working towards sustainable urban water management: the vulnerability blind spot

The unprecedented water scarcity in Australia coincides with the adoption of a new urban water rhetoric. The 'Security through Diversity' strategy has been adopted in a number of Australian cities as a new and innovative approach to urban water management. Although this strategy offers a more holistic approach to urban water management, in practice, the Security through Diversity strategy is largely being interpreted and implemented in a way that maintains the historical dependence on large scale, centralised water infrastructure and therefore perpetuates existing urban water vulnerabilities. This research explores the implementation of Security through Diversity as the new water scarcity response strategy in the cities of Perth and Melbourne. Through a qualitative study with over sixty-five urban water practitioners, the results reveal that the practitioners have absorbed the new Security through Diversity language whilst maintaining the existing problem and solution framework for urban water management. This can be explained in terms of an entrenched technological path dependency and cognitive lock-in that is preventing practitioners from more comprehensively engaging with the complexities of the Security through Diversity strategy, which is ultimately perpetuating the existing vulnerability of our cities. This paper suggests that greater engagement with the underlying purpose of the security though diversity strategy is a necessary first step to overcome the constraints of the traditional technological paradigm and more effectively reduce the continued vulnerability of Australian cities.     

Sensitivity analysis for the SimpleTreat model to simulate fate of chemicals in sewage treatment plants

SimpleTreat 3.1 predicts the distribution and elimination of chemicals by sewage treatment. The model is used as the default calculation in EUSES 2.0 to estimate exposure concentration in the receiving water, soil and air. A sensitivity analysis was performed to rank input parameters according to their influence on model predictions. Triclosan was selected for the base case. The sewage flow, degradation rates and parameters describing the raw sewage were shown to be the most sensitive inputs. The pH and dissociation constant are very sensitive parameters when working with ionisable compounds. Variation in certain input parameters was propagated through the model to yield greater variation in output parameters with a maximum ratio of 4.0. SimpleTreat 3.1 is a steady state model describing a highly non-steady system. A large variability in the most sensitive parameters is expected within a single sewage plant and parameters should therefore be selected to cover this variability.     

Learning market prices in real-time supply chain management

This paper proposes a model for dynamic pricing that combines knowledge of production capacity and existing commitments, reasoning about uncertainty and learning of market conditions in an attempt to optimise expected profits. In particular, the market conditions are represented as a set of probabilities over the success rate of product prices, and those prices are learned online as the market develops. The dynamic pricing model is integrated into a real-time supply chain management agent using the Trading Agent Competition Supply Chain Management game as a test framework. We evaluate the agent experimentally in competition with other supply chain agents, and demonstrate the benefits of incorporating more market data into the dynamic pricing mechanism.     

Postural support strategies of disabled drivers and the effectiveness of postural support aids

The paper discusses a series of driving trials that were conducted to investigate postural stability of disabled drivers and to assess the effectiveness of a representative sample of support aids. Twenty-three disabled drivers with varying levels of physical disability and seven non disabled drivers participated in the study. The test car was equipped with transducers to measure vehicle velocity and acceleration (longitudinal and lateral), steering wheel movement and torque, and the bracing forces exerted by the driver on the steering wheel. Video cameras were installed to record postural support strategies and displacement of the driver and to record deviation of the car from the specified path. Subjective data regarding driver attitudes and acceptance were also collected through the administration of questionnaires. Findings from the study showed that support aids significantly improved driving performance and reduced physical exertion to maintain an upright driving position for disabled drivers. However, ergonomics design aspects regarding the ease of use and acceptance of the support aids by the end users were identified as obstacles to their sustained use in everyday driving.     

Physicochemical properties of calcific deposits isolated from porcine bioprosthetic heart valves removed from patients following 2-13 years function

The purpose of this study was to characterize the physicochemical properties of calcific deposits that cause the failure of tissue-derived heart valve bioprostheses. This was done in an effort to understand the mechanism of pathologic biomineralization in the cardiovascular system and potentially prevent deterioration of bioprostheses. Calcific deposits taken from 10 failed bioprosthetic valves that had been implanted in patients for 2-13 years were characterized by chemical analysis, x-ray diffraction, FTIR spectroscopy, scanning electron microscopy, polarized light microscopy, and solubility measurements. The combined results identified the biomineral as an apatitic calcium phosphate salt with substantial incorporation of sodium, magnesium and carbonate. The average Ca/PO4 ratio for this "young" pathologic biomineral was approximately 1.3, considerably lower than approximately 1.7 found in mature atherosclerotic plaque biomineral and mature skeletal biomineral, both of which approximate hydroxyapatite in composition. Deproteinated calcific deposits from bioprostheses had thermodynamic solubilities comparable to those of both atherosclerotic plaque, typical pathologic biomineral and hydrolyzed octacalcium phosphate (OCP, Ca4H(PO4)3 x 2.5 H2O), a proposed precursor phase to biomineral apatite. This later finding, together with chemical composition and structural details of the bioprosthetic deposits themselves, supports a mechanism of cardiovascular calcification in which OCP plays a crucial role in the formation of the final apatitic phase. This suggests an approach toward prevention of bioprosthetic tissue calcification through control of the formation of the kinetically favored OCP precursor and/or its transformation into bioapatite.