Isolation and characterization of charge-tagged phenylperoxyl radicals in the gas phase : direct evidence for products and pathways in low temperature benzene oxidation

The phenylperoxyl radical has long been accepted as a critical intermediate in the oxidation of benzene and an archetype for arylperoxyl radicals in combustion and atmospheric chemistry. Despite being central to many contemporary mechanisms underpinning these chemistries, reports of the direct detection or isolation of phenylperoxyl radicals are rare and there is little experimental evidence connecting this intermediate with expected product channels. We have prepared and isolated two charge-tagged phenyl radical models in the gas phase [i.e., 4-(N,N,N-trimethylammonium) phenyl radical cation and 4-carboxylatophenyl radical anion] and observed their reactions with dioxygen by ion-trap mass spectrometry. Measured reaction rates show good agreement with prior reports for the neutral system (k(2)[(Me3N+)C6H4 center dot + O-2] = 2.8 x 10(-11) cm(3) molecule(-1) s(-1), Phi = 4.9%; k(2)[(-O2C)C6H4 center dot + O-2] = 5.4 x 10(-1)1 cm(3) molecule(-1) s(-1), Phi = 9.2%) and the resulting mass spectra provide unequivocal evidence for the formation of phenylperoxyl radicals. Collisional activation of isolated phenylperoxyl radicals reveals unimolecular decomposition by three pathways: (i) loss of dioxygen to reform the initial phenyl radical; (ii) loss of atomic oxygen yielding a phenoxyl radical; and (iii) ejection of the formyl radical to give cyclopentadienone. Stable isotope labeling confirms these assignments. Quantum chemical calculations for both charge-tagged and neutral phenylperoxyl radicals confirm that loss of formyl radical is accessible both thermodynamically and entropically and competitive with direct loss of both hydrogen atom and carbon dioxide.

A biomechanical analysis of anterior instrumentation used in the surgical correction of adolescent idiopathic scoliosis

Scoliosis is a deformity of the spine which affects children and adolescents, and remains a challenge to treat. This study measured the forces used during surgery to correct scoliosis and studied changes to spinal mechanics from the implantation of metal rods used to hold the spine straight. The results of this study will help surgeons and engineers understand how to straighten the spine more efficiently to provide patients with better outcomes.

Vocational education in science technology, engineering and maths (STEM) : Curriculum innovation through industry school partnerships

Governments have recognised that the technological trades rely on knowledge embedded traditionally in science, technology, engineering and mathematics (STEM) disciplines. In this paper, we report preliminary findings on the development of two curricula that attempt to integrate science and mathematics with workplace knowledge and practices. We argue that these curricula provide educational opportunities for students to pursue their preferred career pathways. These curricula were co-developed by industry and educational personnel across two industry sectors, namely, mining and aerospace. The aim was to provide knowledge appropriate for students moving from school to the workplace in the respective industries. The analysis of curriculum and associated policy documents reveals that the curricula adopt applied learning orientations through teaching strategies and assessment practices which focus on practical skills. However, although key theoretical science and maths concepts have been well incorporated, the extent to which knowledge deriving from workplace practices is included varies across the curricula. Our findings highlight the importance of teachers having substantial practical industry experience and the role that whole school policies play in attempts to align the range of learning experiences with the needs of industry.

More than simple living : a cultural perspective on sustainable living

This paper provides a cultural perspective to the sustainability research within HCI. I draw on the results from an ethnographic field study of sustainable household practices of ten women belonging to the so-called middle class in India. Focusing on their reuse practices, I provide examples of domestic artefacts that are creatively and resourcefully reused from worn-out artefacts. My initial findings show that the rationale behind creating such artefacts is not limited to the practicality and usefulness, but how cultural and religious beliefs are incorporated into such practices.

Designing for Awareness: An Experience-focused HCI Perspective

Within Human-Computer Interaction (HCI) and Computer Supported Cooperative Work (CSCW) research, the notion of technologically-mediated awareness is often used for allowing relevant people to maintain a mental model of activities, behaviors and status information about each other so that they can organize and coordinate work or other joint activities. The initial conceptions of awareness focused largely on improving productivity and efficiency within work environments. With new social, cultural and commercial needs and the emergence of novel computing technologies, the focus of technologically-mediated awareness has extended from work environments to people’s everyday interactions. Hence, the scope of awareness has extended from conveying work related activities to people’s emotions, love, social status and other broad range of aspects. This trend of conceptualizing HCI design is termed as experience-focused HCI. In my PhD dissertation, designing for awareness, I have reported on how we, as HCI researchers, can design awareness systems from experience-focused HCI perspective that follow the trend of conveying awareness beyond the task-based, instrumental and productive needs. Within the overall aim to design for awareness, my research advocates ethnomethodologically-informed approaches for conceptualizing and designing for awareness. In this sense, awareness is not a predefined phenomenon but something that is situated and particular to a given environment. I have used this approach in two design cases of developing interactive systems that support awareness beyond task-based aspects in work environments. In both the cases, I have followed a complete design cycle: collecting an in-situ understanding of an environment, developing implications for a new technology, implementing a prototype technology to studying the use of the technology in its natural settings.

Protecting web 2.0 services from botnet exploitations

Recently, botnet, a network of compromised computers, has been recognized as the biggest threat to the Internet. The bots in a botnet communicate with the botnet owner via a communication channel called Command and Control (C & C) channel. There are three main C & C channels: Internet Relay Chat (IRC), Peer-to-Peer (P2P) and web-based protocols. By exploiting the flexibility of the Web 2.0 technology, the web-based botnet has reached a new level of sophistication. In August 2009, such botnet was found on Twitter, one of the most popular Web 2.0 services. In this paper, we will describe a new type of botnet that uses Web 2.0 service as a C & C channel and a temporary storage for their stolen information. We will then propose a novel approach to thwart this type of attack. Our method applies a unique identifier of the computer, an encryption algorithm with session keys and a CAPTCHA verification.

Health monitoring of short-and medium-spen bridges using an improved modal strain energy method

Increasing the importance and use of infrastructures such as bridges, demands more effective structural health monitoring (SHM) systems. SHM has well addressed the damage detection issues through several methods such as modal strain energy (MSE). Many of the available MSE methods either have been validated for limited type of structures such as beams or their performance is not satisfactory. Therefore, it requires a further improvement and validation of them for different types of structures. In this study, an MSE method was mathematically improved to precisely quantify the structural damage at an early stage of formation. Initially, the MSE equation was accurately formulated considering the damaged stiffness and then it was used for derivation of a more accurate sensitivity matrix. Verification of the improved method was done through two plane structures: a steel truss bridge and a concrete frame bridge models that demonstrate the framework of a short- and medium-span of bridge samples. Two damage scenarios including single- and multiple-damage were considered to occur in each structure. Then, for each structure, both intact and damaged, modal analysis was performed using STRAND7. Effects of up to 5 per cent noise were also comprised. The simulated mode shapes and natural frequencies derived were then imported to a MATLAB code. The results indicate that the improved method converges fast and performs well in agreement with numerical assumptions with few computational cycles. In presence of some noise level, it performs quite well too. The findings of this study can be numerically extended to 2D infrastructures particularly short- and medium-span bridges to detect the damage and quantify it more accurately. The method is capable of providing a proper SHM that facilitates timely maintenance of bridges to minimise the possible loss of lives and properties.