Interpreting electrochemical noise resistance as a statistical linear polarisation resistance

A theoretical analysis on the electrochemical noise resistance is carried out based on basic electrochemical corrosion theory. It is proven that the noise resistance is equivalent to the polarisation resistance and is in fact a special form of linear polarisation resistance, namely statistical linear polarisation resistance.

Dynamic nuclear polarisation enhanced (14)N overtone MAS NMR spectroscopy.

Dynamic nuclear polarisation (DNP) has been used to obtain magic angle spinning (14)N(OT) (nitrogen-14 overtone) solid-state NMR spectra from several model amino acids, with both direct and indirect observation of the (14)N(OT) signal. The crystalline solids were impregnated with biradical solutions of organic liquids that do not dissolve the crystalline phase. The bulk phase was then polarized via(1)H spin diffusion from the highly-polarized surface (1)H nuclei, resulting in (1)H DNP signal enhancements of around two orders of magnitude. Cross polarisation from (1)H nuclei directly to the (14)N overtone transition is demonstrated under magic angle spinning, using a standard pulse sequence with a relatively short contact time (on the order of 100 μs). This method can be used to acquire (14)N overtone MAS powder patterns that match closely with simulated line shapes, allowing isotropic chemical shifts and quadrupolar parameters to be measured. DNP enhancement also allows the rapid acquisition of 2D (14)N(OT) heteronuclear correlation spectra from natural abundance powder samples. (1)H-(14)N(OT) HETCOR and (13)C-(14)N(OT) HMQC pulse sequences were used to observe all single-bond H-N and C-N correlations in histidine hydrochloride monohydrate, with the spectra obtained in a matter of hours. Due to the high natural abundance of the (14)N isotope (99.6%) and the advantages of observing the overtone transition, these methods provide an attractive route to the observation of C-N correlations from samples at natural isotopic abundance and enable the high resolution measurement of (14)N chemical shifts and quadrupolar interaction parameters.

For goodness sake! Postlogographically de-(dis)positioning education research

How are education researchers and their research now positioned? Where are education research and researchers now positioned in the public/private debate? What is the position of practitioner research in these circumstances? My paper introduces 'post logography' as a researching trope for perturbing structuralist analytic methods towards interpreting post structuralising complexities that challenge the 'positioning' of education/research/researchers.

I discuss interpreting researching with and in (with-in) educating as intertwining ways, for turning the analytical objectivity that 'positions' subjective 'facts' as essentialised 'goods', towards exploring generative states of 'goodness'.

Education and its research are typically cast as separate constructs (like teaching and outcomes) for defining the subjectification of educational objects as valuable 'goods' - especially those with private economic value.

I argue that researched educational 'goods' are mostly teaching and outcomes focussed, and mainly privately positioned, whereas researching with-in educating for 'goodness' concerns a public disposition of exploring-learning-generativity for social knowing-acting.

I am theorising that through postlogographically de-positioning the predominance of 'facts' as private 'goods', and thereby recognising interpretive states concerning and generating 'goodness', the reductive polarisation of education/research, public/private, theorist/practitioner turns towards understanding complex continua for exploring-learning-generativity, which introduce new horizons of significance for social knowing-acting.

Doing justice' : stories of everyday life in disadvantaged schools and neighbourhoods

I worked as a school administrator in 'disadvantaged schools' for many years. In this study I asked colleagues from sixteen schools in the northern and western suburbs of Adelaide to co - theorise about changes in their neighbourhood, school populations and programs, now that their schools are no longer recognised by policy as 'disadvantaged1. I explore the use of narrative method and arts based approaches by constructing a 'literary' research text that uses conventional sociological forms together with images, poetry and personal stories. I use anthropological and geographical theoretical constructs to look at the changing material, economic, cultural and social landscapes and the mosaic of inequalities in the city of Adelaide. I suggest that this is not a simple binary polarisation, although large numbers of people are similarly positioned by de-industrialisation and the diminishing social wage. After examining the literature on poverty in Australia, I am eventually prepared to call this space class, understanding that this is a sociological metaphor. Through a theorisation of each school as a 'place' within a specific neighbourhood, I look at the similarities and differences across sites. I suggest that 'disadvantaged schools' are similarly positioned as sites for the mediation of social inequalities, and that this can be readily seen in the time consuming 'housework' of discipline and welfare. I indicate how each school is differently able to 'do more with less', because of their unique neighbourhood and its narratives, knowledges, histories, teleologies and people. I show that the common coercive regimes of market devolution, new public management and the 'distributive curriculum' frame the work of teachers, students and administrators in ways that are not conducive to 'doing justice', despite the policy rhetoric of equity and community. I provide evidence that the neoliberal imaginary of context free schooling enshrined in effective schools literatures is Utopian and irrational. I argue that the capacity of the school to 'generate context' is always paradoxically dependent on 'context derived'. I discuss the notion of 'doing justice' and the benefits of 'disadvantaged schools' having a local set of principles that guide their decisions and actions and provide evidence that the school administrator's understandings of 'doing justice' are important. I also suggest that, despite being increasingly isolated and hindered by policy directions, the majority of the sixteen schools continue to work for and with principles of justice and equity, drawing on a range of emotional and intellectual resources and deep, longstanding commitments. I conclude by speculating on the kinds of policy and research agendas that might take account of both the commonalities and differences amongst 'disadvantaged schools', and what might be included in a comprehensive and systematic approach to 'doing justice'.

Paths to Buddhahood : the "sudden" and "gradual" awakening models in Mah ̄y n̄a and Vajray n̄a Buddhism

Examines the graduated paths of Mah ȳn̄a and Vajrayn̄a Buddhism and the instantaneous paths of Ch'an/Zen, rDzogs chen and Mahm̄udr.̄ The main contention between these approaches relates to how the mental defilements are to be purified and how the positive qualities of Buddhahood are to be realised. After comparing and examining the paths it is argued that the polarisation of the "sudden" and "gradual" approaches is the result of the critical philosophies of late Indian and Tibetan Buddhism, rather than a real spiritual dilemma for adherents of either path.

Research paradigms in environmental education : post war reconciliation?

Methodological self-reflection is an aspect of research rigour. Yet the "politics of method" perspective has been slow to take hold in North American environmental education. While arguments have been made concerning the need for deliberation about and congruence among the political theories of substance and method, polarisation of quantitative and qualitative researchers has tended to persist. This presentation provides an outline of the issues arising at a recent forum which aimed to transcend this polarisation of research in environmental education.

Monitoring the corrosion of concrete reinforcement using control curves

Corrosion testing (half-cell and LPR) was carried out on a number reinforced concrete panels which had been taken from the fascia of a twenty five year old high rise building in Melbourne, Australia. Corrosion, predominantly as a result of carbonation of the concrete, was associated with a limited amount of cracking. A monitoring technique was established in which probe electrodes (reference and counter) were retro-fitted into the concrete. The probe electrode setup was identical for all panels tested. It was found that the corrosion behaviour of all panels tested closely fitted a family of results when the corrosion potential is plotted against the polarisation resistance (Rp). This enabled the development of a so-called 'control curve' relating the corrosion potential to the Rp for all of the panels under investigation. This relationship was also confirmed on laboratory samples, indicating that for a fixed geometry and experimental conditions a relationship between the potential and polarisation resistance of steel can be established for the steel-concrete system. Experimental results will be presented which indicate that for a given monitoring cell geometry, it may be possible to propose criteria for the point at which remediation measures should be considered. The establishment of such a control curve has enabled the development of a powerful monitoring tool for the assessment of a number of proposed corrosion remediation techniques. The actual effect of any corrosion remediation technique becomes clearly apparent via the type and magnitude of deviation of post remediation data from the original (preremediation) control curve.

Transient response analysis of steel in concrete

A new approach is presented for the analysis of galvanostatically induced transients allowing for the rapid evaluation of the corrosion activity of steel in concrete. This method of analysis is based on the iterative fitting of a non-exponential model based on a modified KWW (Kohlrausch–Williams–Watt) formalism. This analysis yields values for the parameters related to corrosion such as the concrete resistance, polarisation resistance, interfacial capacitance and β, the non-ideality exponent.

On the electrochemical response and interfacial properties of steel–Ca(OH)2 and the steel–concrete system measured using galvanostatic pulses

The interfacial properties of the steel–concrete system are examined via a new approach for evaluation of galvanostatic pulse data. This methodology allows for rapid determination of the corrosion activity of steel, and readily yields values for parameters related to corrosion such as the polarisation resistance and interfacial capacitance. The method of analysis is based on the iterative fitting of a non-exponential model based on a modified Kohlrausch–Williams–Watt (KWW) formalism. The transient behaviour of steel in concrete is non-exponential in its form and, when analysed this way, an exponent β can be determined characterising the exponential non-ideality of the transient. This non-ideality parameter is found to differ significantly for actively corroding and passive specimens, thereby serving as a useful index to the level of corrosion being experienced. Furthermore, the investigation of the interfacial characteristics of the system, previously unobtainable in a reproducible manner via other electrochemical methods, reveal information regarding the kinetic factors governing corrosion of steel in concrete.

The corrosion inhibition mechanism of new rare earth cinnamate compounds — electrochemical studies

A combination of linear polarisation resistance (LPR) and cyclic potentiodynamic polarisation (CPP) measurements demonstrated that the lanthanum-4 hydroxy cinnamate compound could inhibit both the cathodic and anodic corrosion reactions on mild steel surfaces exposed to 0.01 M NaCl solutions. However, the dominating response was shown to vary with inhibitor concentration. At the concentrations for which the highest level of protection was achieved, both REM-4 hydroxy cinnamate (REM being lanthanum and mischmetal) displayed a strong anodic behaviour for mild steel and their inhibition performance, including their resistance against localised attack, improved with time.

Electrochemical impedance spectroscopy (EIS) measurements and modelling were carried out so as to propose a simple electrical model and correlate the extracted parameters to the inhibition mechanism put forward for REM-cinnamate based compounds. The results supported the high corrosion inhibition performance of the compounds as well as the build-up of a protective film with time. Based on a two-layer model the results suggested that the upper layer of the inhibitor film seemed to offer less resistance to the diffusion of electrochemically active species than the highly resistive inner layer at the film/metal interface.

Corrosion protection of AA2024-T3 using rare earth diphenyl phosphates

Existing corrosion protection technologies for aluminium alloys utilising chromates are environmentally damaging and extremely toxic. This paper presents a preliminary investigation into rare earth diphenyl phosphates as new environmentally benign corrosion inhibitors. Full immersion weight loss experiments, cyclic potentiodynamic polarisation measurements and Raman spectroscopy were used in this study. Results show cerium diphenyl phosphate (Ce(dpp)₃) acts as a cathodic inhibitor, decreasing cathodic current density and E_corr by passivating cathodic intermetallic particles on the alloy surface. Mischmetal diphenyl phosphate (Mm(dpp)₃) acts a mixed inhibitor, shifting E_corr to more noble values, decreasing cathodic current density, increasing the breakdown potential and suppressing pitting.