Oxygen Tracer Diffusion in Vitreous Silica

Oxygen diffusion in vitreous silica glass is studied using the gas exchange technique. The tracer concentration profiles are consistent with a model based on two mechanisms, one network and the other interstitial. These processes are coupled through limited network–interstitial exchange. Nuclear reaction analysis and secondary ion mass spectrometry techniques are performed and compared. These results are compared to experiments on transport in thin silica films grown on single-crystal silicon.     

Cognitive-bias toward gaming-related words and disinhibition in World of Warcraft gamers

This study investigated cognitive biases toward gaming-related words and differences in cognitive performance among twelve World of Warcraft players (WWP) and thirty non-players (NP). We measured response to valenced common English and WoW jargon words using a computer-based go/no-go task. Sometimes positive valence words were the targets for the ‘go’ response, with negative-valence words as the distracters, sometimes the reverse. Target discrimination (d′) and response disinhibition (C) were calculated using a signal detection analysis. Based on questionnaire responses, there were no differences between groups in depression, anxiety, smoking or drinking, but WWP reported significantly more screen and gaming time (17.31 h/week versus 4.12 among NP). WWP had faster reaction time (RT) and better discrimination of targets from distracters (high d′) but also showed higher disinhibition (low C). WWP also showed cognitive-bias toward game-related words in the form of higher d′ for WoW jargon than common English and more disinhibition to positive-valence WoW jargon. Similar to past studies which have found alcoholics to have cognitive biases toward alcohol-related words, WWP who play frequently showed cognitive biases toward words related to the World of Warcraft game.     

“Leagile” software development: An experience report analysis of the application of lean approaches in agile software development

In recent years there has been a noticeable shift in attention from those who use agile software development toward lean software development, often labelled as a shift “from agile to lean”. However, the reality may not be as simple or linear as this label implies. To provide a better understanding of lean software development approaches and how they are applied in agile software development, we have examined 30 experience reports published in past agile software conferences in which experiences of applying lean approaches in agile software development were reported. The analysis identified six types of lean application. The results of our study show that lean can be applied in agile processes in different manners for different purposes. Lean concepts, principles and practices are most often used for continuous agile process improvement, with the most recent introduction being the kanban approach, introducing a continuous, flow-based substitute to time-boxed agile processes.     

Experimental and numerical evaluation of electromagnetic acoustic transducer performance on steel materials

Electromagnetic Acoustic Transducers (EMATs) are an attractive alternative to standard piezoelectric probes in a number of applications thanks to their contactless nature. EMATs do not require any couplant liquid and are able to generate a wide range of wave-modes; however these positive features are partly counterbalanced by a relatively low signal-to-noise ratio and by the dependence of EMAT performance on the material properties of the test object. A wide variety of steel materials is employed in many industrial applications, so it is important to assess the material-dependent behaviour of EMATs when used in the inspection of different types of steel. Experimental data showing the performance of bulk shear wave EMATs on a wide range of steels is presented, showing the typical range of physical properties encountered in practice. A previously validated Finite Element model, including the main transduction mechanisms, the Lorentz force and magnetostriction, is used to evaluate the experimental data. The main conclusion is that the Lorentz force is the dominant transduction effect, regardless of the magnitude and direction of the bias magnetic field. Differently from magnetostriction, the Lorentz force is not significantly sensitive to the typical range of physical properties of steels, as a consequence the same EMAT sensor can be used on different grades of ferritic steel.     

Artificial disbonds for calibration of transient thermography inspection of thermal barrier coating systems

Transient thermography is commonly used for the detection of disbonds in thermal barrier coatings (TBC). As for other NDT techniques, reference test specimens are required for calibration, but unfortunately, real disbonds are very difficult to use because it is difficult to control their size, and large ones tend to spall. Flat bottomed holes are commonly used, but these over-estimate the thermal contrast obtained for a defect of a given diameter. This paper quantifies the differences in thermal response using finite element analysis validated by experiments, and proposes a form of artificial disbond that gives a better representation of the thermal responses seen with real defects. Real disbonds tend to have a non-uniform gap between the disbonded surfaces across the defect, and the effect of this on the thermal response is evaluated using finite element simulations. It is shown that the effect can be compensated for by adjusting the diameter of the calibration defect compared to the real defect.     

On a fast, compact approximation of the exponential function

Recently Schraudolph (1999) described an ingenious, fast, and compact approximation of the exponential function through manipulation of the components of a standard (IEEE-754 (IEEE, 1985)) floating-point representation. This brief note communicates a recoding of this procedure that overcomes some of the limitations of the original macro at little or no additional computational expense.     

Peer reviewed: environmental sleuth at work

A combination of technical approaches and forensic tools can determine historic causes, timing, and impacts of site contamination.     

Integrin receptors and hairy cell leukaemia

The ability of a cell to recognize and specifically localise within an appropriate tissue environment is essential to the proliferation and survival of that cell. The integrin family of cell-surface adhesion-receptors are essential to such tissue localisation, allowing a migrating cell to specifically recognise, localise within-, and respond to- the cellular or extracellular matrix ligands that characterise a given tissue. We have investigated how the expression and activity of integrin receptors underlies the consistent and unusual tissue distribution of the malignant B lymphocytes of hairy cell leukaemia (HCL). In this report we review our published work in this area. Our findings are then discussed within the context of current knowledge of integrin receptors and their ligands, and in relation to the clinical features of HCL.     

Literacy and computer literacy: Definitions and comparisons

This paper analyzes the prevailing definitions of literacy and computer literacy. It is shown that similar factors confound our understanding of both these terms. In addition we argue that the term computer literacy is highly inappropriate. In order to clarify the meaning of these terms we suggest a hierarchy of definitions, from the operational level to the broader socio-political definitions.The paper proposes the following. Firstly a definition for the operational skills of reading and writing, for which Papert's term letteracy is used. Secondly a corresponding definition for the operational skills required to use a computer, for which the new term comperacy is proposed. Both these terms represent a continuum of skill levels and a classification for these levels is also developed. The paper concludes with an examination of the interdependencies between letteracy and comperacy which can serve as the first step in a broader analysis of the relationship between literacy and computer literacy.