Direct ink writing of bismuth molybdate microwave dielectric ceramics

Additive manufacturing via direct ink writing and microwave dielectric characterisation of commercially produced low sintering temperature bismuth molybdenum oxide ceramics, have been both performed for the first time, following a powder-to-product holistic approach. We demonstrated that direct ink writing is an excellent candidate for producing dielectric substrates to be used for wireless telecommunication applications operating at microwave (MW) frequencies, with great repeatability and properties comparable to ceramics fabricated via conventional processing routes. The optimum density (relative density of ρ_r ≈ 93%) of the 3D printed test samples was obtained by sintering at 660 °C for 2 h, resulting in a relative permittivity ε_r = 35.7, dielectric loss tanδ = 0.0004 and microwave quality factor Q × f = 14,928 GHz. Sintering at higher temperatures promoted a porosity increase due to mismatching grain growth mechanisms and phase decomposition, that collectively hindered the test samples’ microwave dielectric performance in terms of achievable relative permittivity (ε_r) and dielectric loss (tanδ).     

Electromagnetic interference shielding effectiveness of carbon-based materials prepared by screen printing

Screen printing, as a simple and efficient method, is used to fabricate a carbon-based film for electromagnetic interference (EMI) shielding applications. The results show that carbon nanotube (CNT) sheets are more effective in providing EMI shielding compared to graphite and carbon black sheets in abroad-band frequency range due to better electron transmission. A thin printed 150 μm 15 wt% CNT film exhibits similar shielding performance to a thicker 1.5 mm 15 wt% CNT epoxy composites, illustrating that screen printing could be a promising approach to fabricate thin EMI shielding films for commercial applications.     

Design and Implementation of the Robotic Platform

The diversity of robotic research areas along with the complex requirements of hardware and software for robotic systems have always presented a challenge for system developers. Many past robot control platforms were complex, expensive, and not very user friendly. Even though several of the previous platforms were designed to provide an open architecture system, very few of the previous platforms have been reused. To address previous disadvantages, this paper describes the design and implementation of the Robotic Platform, an object-oriented development platform for robotic applications. The Robotic Platform includes hardware interfacing, servo control, trajectory generation, 3D simulation, a graphical user interface, and a math library. As opposed to distributed solutions, the Robotic Platform implements all these components in a homogenous architecture that utilizes a single hardware platform (a standard PC), a single programming language (C++), and a single operating system (the QNX Real-Time Platform) while guaranteeing deterministic real-time performance. This design leads to an open architecture that is less complex, easier to use, and easier to extend. Particularly, the area of multiple cooperating robots benefits from this kind of architecture, since the Robotic Platform achieves a high integration of its components and provides a simple and flexible means of communication. The architecture of the Robotic Platform builds on the following state-of-the-art technologies and general purpose components to further increase simplicity and reliability: (i) PC technology, (ii) the QNX Real-Time Platform, (iii) the Open Inventor library, (iv) object-oriented design, and (v) the QMotor control environment.     

Quantitative online prediction of peptide binding to the major histocompatibility complex

With its implications for vaccine discovery, the accurate prediction of T cell epitopes is one of the key aspirations of computational vaccinology. We have developed a robust multivariate statistical method, based on partial least squares, for the quantitative prediction of peptide binding to major histocompatibility complexes (MHC), the principal checkpoint on the antigen presentation pathway. As a service to the immunobiology community, we have made a Perl implementation of the method available via a World Wide Web server. We call this server MHCPred. Access to the server is freely available from the URL: http://www.jenner.ac.uk/MHCPred. We have exemplified our method with a model for peptides binding to the common human MHC molecule HLA-B*3501.     

Providing assistance to older users of dynamic Web content

The much vaunted Web 2.0 sees once static pages evolving into hybrid applications. Content that was once simple to surf is now becoming increasingly complicated due to the many updating components “dotted” throughout the page. In previous studies, we have shown that unlike younger users, older users have more varied interaction patterns when using dynamic content. In addition, some older users are not aware of what to expect when interacting with dynamic content and show signs of hesitancy when completing tasks. Therefore, a tool was developed to assist older users as they interacted with these kinds of pages. The tool used simple language and video demonstrations to explain how the dynamic content operated and what users could expect to happen as they were interacting with it. We found that: older users tend to deny the need for assistance technology even when non-subjective measures suggest they do use it; technology assists but cannot replace initial human training; Assistance Tools are seen as a ‘security blanket’ incase things go wrong; and that the actual needs of users are not that well understood by those users.     

Non-negative Matrix Factorization with Orthogonality Constraints and its Application to Raman Spectroscopy

We introduce non-negative matrix factorization with orthogonality constraints (NMFOC) for detection of a target spectrum in a given set of Raman spectra data. An orthogonality measure is defined and two different orthogonality constraints are imposed on the standard NMF to incorporate prior information into the estimation and hence to facilitate the subsequent detection procedure. Both multiplicative and gradient type update rules have been developed. Experimental results are presented to compare NMFOC with the basic NMF in detection, and to demonstrate its effectiveness in the chemical agent detection problem.     

The moderating role of subordinate political skill on supervisors' impressions of subordinate ingratiation and ratings of subordinate interpersonal facilitation.

Nearly 2 decades ago, social influence theorists called for a new stream of research that would investigate why and how influence tactics are effective. The present study proposed that political skill affects the style of execution of influence attempts. It utilized balance theory to explain the moderating effect of employee political skill on the relationships between self- and supervisor-reported ingratiation. Additionally, supervisor reports of subordinate ingratiation were hypothesized to be negatively related to supervisor ratings of subordinate interpersonal facilitation. Results from a combined sample of 2 retail service organizations provided evidence that subordinates with high political skill were less likely than those low in political skill to have their demonstrated ingratiation behavior perceived by targets as a manipulative influence attempt. Also, when subordinates were perceived by their supervisors to engage in more ingratiation behavior, the subordinates were rated lower on interpersonal facilitation. Implications of these findings, limitations, and future research directions are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Saving a creek one bid at a time: A uniform price auction for urban stormwater retention

Urban stormwater runoff degrades waterway health. We describe a market-based approach to identify the most efficient investments to reduce urban stormwater impacts at minimum cost. The framework involves the joint consideration of public and private supply of environmental services across scales; a metric to compare the benefits of interventions across and within scales; an environmental procurement auction to reveal and minimise the cost of private interventions; and an endogenous reserve price to select the optimal portfolio of investments. The paper discusses the economic and environmental rationale for the proposed approach, along with the results of Stormwater Tender, a field trial in Melbourne, Australia. To conceptualize the optimal portfolio of investments we draw the aggregate supply curve and the production possibility frontier (PPF) using data from the field trial. We find considerable heterogeneity in both the private and public cost of providing environmental benefits, highlighting the need to consider interventions across a range of scales. We also find that existing theory is limited in its ability to predict bidders' behaviour. Despite this, it is evident that using the PPF to select projects considerably improves the cost effectiveness of the investment. We therefore conclude that the approach is an effective way of maximising the benefits of policy interventions to reduce the impacts of stormwater on urban waterways.