Premonolayer oxidation of nanostructured gold : an important factor influencing electrocatalytic activity

The study of the electrodeposition of polycrystalline gold in aqueous solution is important from the viewpoint that in electrocatalysis applications ill-defined micro- and nanostructured surfaces are often employed. In this work, the morphology of gold was controlled by the electrodeposition potential and the introduction of Pb(CH3COO)2•3H2O into the plating solution to give either smooth or nanostructured gold crystallites or large dendritic structures which have been characterized by scanning electron microscopy (SEM). The latter structures were achieved through a novel in situ galvanic replacement of lead with AuCl4−(aq) during the course of gold electrodeposition. The electrochemical behavior of electrodeposited gold in the double layer region was studied in acidic and alkaline media and related to electrocatalytic performance for the oxidation of hydrogen peroxide and methanol. It was found that electrodeposited gold is a significantly better electrocatalyst than a polished gold electrode; however, performance is highly dependent on the chosen deposition parameters. The fabrication of a deposit with highly active surface states, comparable to those achieved at severely disrupted metal surfaces through thermal and electrochemical methods, does not result in the most effective electrocatalyst. This is due to significant premonolayer oxidation that occurs in the double layer region of the electrodeposited gold. In particular, in alkaline solution, where gold usually shows the most electrocatalytic activity, these active surface states may be overoxidized and inhibit the electrocatalytic reaction. However, the activity and morphology of an electrodeposited film can be tailored whereby electrodeposited gold that exhibits nanostructure within the crystallites on the surface demonstrated enhanced electrocatalytic activity compared to smaller smooth gold crystallites and larger dendritic structures in potential regions well within the double layer region.

Electrochemical formation of porous copper 7, 7, 8, 8-tetracyanoquinodimethane and copper 2, 3, 5, 6-tetrafluoro-7, 7, 8, 8-tetracyanoquinodimethane honeycomb surfaces with superhydrophobic properties

The electrochemical formation of highly porous CuTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) and CuTCNQF4 (TCNQF4 = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) materials was undertaken via the spontaneous redox reaction between a porous copper template, created using a hydrogen bubbling template technique, and an acetonitrile solution containing TCNQ or TCNQF4. It was found that activation of the surface via vigorous hydrogen evolution that occurs during porous copper deposition and TCNQ mass transport being hindered through the porous network of the copper template influenced the growth of CuTCNQ and CuTCNQF4. This approach resulted in the fabrication of a honeycomb layered type structure where the internal walls consist of very fine crystalline needles or spikes. This combination of microscopic and nanoscopic roughness was found to be extremely beneficial for anti-wetting properties where superhydrophobic materials with contact angles as high as 177° were created. Given that CuTCNQ and CuTCNQF4 have shown potential as molecular based electronic materials in the area of switching and field emission, the creation of a surface that is moisture resistant may be of applied interest.

Structural characterization and vibrational spectroscopy of the arsenate mineral wendwilsonite

In this paper, we have investigated on the natural wendwilsonite mineral with the formulae Ca2(Mg,Co)(AsO4)2⋅2(H2O). Raman spectroscopy complimented with infrared spectroscopy has been used to determine the molecular structure of the wendwilsonite arsenate mineral. A comparison is made with the roselite mineral group with formula Ca2B(AsO4)2⋅2H2O (where B may be Co, Fe2+, Mg, Mn, Ni, Zn). The Raman spectra of the arsenate related to tetrahedral arsenate clusters with stretching region shows strong differences between that of wendwilsonite and the roselite arsenate minerals which is attributed to the cation substitution for calcium in the structure. The Raman arsenate (AsO4)3− stretching region shows strong differences between that of wendwilsonite and the roselite arsenate minerals which is attributed to the cation substitution for calcium in the structure. In the infrared spectra complexity exists of multiple to tetrahedral (AsO4)3− clusters with antisymmetric stretching vibrations observed indicating a reduction of the tetrahedral symmetry. This loss of degeneracy is also reflected in the bending modes. Strong Raman bands around 450 cm−1 are assigned to ν4 bending modes. Multiple bands in the 350–300 cm−1 region assigned to ν2 bending modes provide evidence of symmetry reduction of the arsenate anion. Three broad bands for wendwilsonite found at 3332, 3119 and 3001 cm−1 are assigned to OH stretching bands. By using a Libowitzky empirical equation, hydrogen bond distances of 2.65 and 2.75 Å are estimated. Vibrational spectra enable the molecular structure of the wendwilsonite mineral to be determined and whilst similarities exist in the spectral patterns with the roselite mineral group, sufficient differences exist to be able to determine the identification of the minerals.

A Raman spectroscopic comparison of calcite and dolomite

Raman spectroscopy was used to characterize and differentiate the two minerals calcite and dolomite and the bands related to the mineral structure. The (CO3)2− group is characterized by four prominent Raman vibrational modes: (a) the symmetric stretching, (b) the asymmetric deformation, (c) asymmetric stretching and (d) symmetric deformation. These vibrational modes of the calcite and dolomite were observed at 1440, 1088, 715 and 278 cm−1. The significant differences between the minerals calcite and dolomite are observed by Raman spectroscopy. Calcite shows the typical bands observed at 1361, 1047, 715 and 157 cm−1, and the special bands at 1393, 1098, 1069, 1019, 299, 258 and 176 cm−1 for dolomite are observed. The difference is explained on the basis of the structure variation of the two minerals. Calcite has a trigonal structure with two molecules per unit cell, and dolomite has a hexagonal structure. This is more likely to cause the splitting and distorting of the carbonate groups. Another cause for the difference is the cation substituting for Mg in the dolomite mineral.

Computer simulation of the fatigue behaviour of roof cladding during the passage of a tropical cyclone

This paper describes the development of an analytical model used to simulate the fatigue behaviour of roof cladding during the passage of a tropical cyclone. The model incorporated into a computer program uses wind pressure data from wind tunnel tests in combination with time history information on wind speed and direction during a tropical cyclone, and experimental fatigue characteristics data of roof claddings. The wind pressure data is analysed using a rainflow form of analysis, and a fatigue damage index calculated using a modified form of Miner's rule. Some of the results obtained to date and their significance in relation to the review of current fatigue tests are presented. The model appears to be reasonable for comparative estimation of fatigue life, but an improvement of Miner's rule is required for the prediction of actual fatigue life.

Local plastic mechanisms in thin steel plates under in-plane compression

Thin-walled steel plates subjected to in-plane compression develop two types of local plastic mechanism, namely the roof-shaped mechanism and the so-called flip-disc mechanism, but the intriguing question of why two mechanisms should develop was not answered until recently. It was considered that the location of first yield point shifted from the centre of the plate to the midpoint of the longitudinal edge depending on the b/t ratio, imperfection level, and yield stress of steel, which then decided the type of mechanism. This paper has verified this hypothesis using analysis and laboratory experiments. An elastic analysis using Galerkin's method to solve Marguerre's equations was first used to determine the first yield point, based on which the local plastic mechanism/imperfection tolerance tables have been developed which give the type of mechanism as a function of b/t ratio, imperfection level and yield stress of steel. Laboratory experiments of thin-walled columns verified the imperfection tolerance tables and thus indirectly the hypothesis. Elastic and rigid-plastic curves were them used to predict the effect on the ultimate load due to the change of mechanism. A finite element analysis of selected cases also confirmed the results from simple analyses and experiments.

Removal of bisphenol A from wastewater by Ca-montmorillonite modified with selected surfactants

Organo Arizona SAz-2 Ca-montmorillonite was prepared with different surfactant (DDTMA and HDTMA) loadings through direct ion exchange. The structural properties of the prepared organoclays were characterized by XRD and BET instruments. Batch experiments were carried out on the adsorption of bisphenol A (BPA) under different experimental conditions of pH and temperature to determine the optimum adsorption conditions. The hydrophobic phase and positively charged surface created by the loaded surfactant molecules are responsible for the adsorption of BPA. The adsorption of BPA onto organoclays is well described by pseudo-second order kinetic model and the Langmuir isotherm. The maximum adsorption capacity of the organoclays for BPA obtained from a Langmuir isotherm was 151.52 mg/g at 297 K. This value is among the highest values for BPA adsorption compared with other adsorbents. In addition, the adsorption process was spontaneous and exothermic based on the adsorption thermodynamics study. The organoclays intercalated with longer chain surfactant molecules possessed a greater adsorption capacity for BPA even under alkaline conditions. This process provides a pathway for the removal of BPA from contaminated waters.

Experimental studies of hollow flange channel beams subject to combined bending and shear actions

This paper presents the details of an experimental study of a cold-formed steel hollow flange channel beam known as LiteSteel Beam (LSB) subject to combined bending and shear actions. The LSB sections are produced by a patented manufacturing process involving simultaneous cold-forming and electric resistance welding. Due to the geometry of the LSB, as well as its unique residual stress characteristics and initial geometric imperfections resultant of manufacturing processes, much of the existing research for common cold-formed steel sections is not directly applicable to LSB. Experimental and numerical studies have been carried out to evaluate the behaviour and design of LSBs subject to pure bending actions and predominant shear actions. To date, however, no investigation has been conducted into the strength of LSB sections under combined bending and shear actions. Combined bending and shear is especially prevalent at the supports of continuous span and cantilever beams, where the interaction of high shear force and bending moment can reduce the capacity of a section to well below that for the same section subject only to pure shear or moment. Hence experimental studies were conducted to assess the combined bending and shear behaviour and strengths of LSBs. Eighteen tests were conducted and the results were compared with current AS/NZS 4600 and AS 4100 design rules. AS/NZS 4600 design rules were shown to grossly underestimate the combined bending and shear capacities of LSBs and hence two lower bound design equations were proposed based on experimental results. Use of these equations will significantly improve the confidence and cost-effectiveness of designing LSBs for combined bending and shear actions.

Application of texture analysis in tear film surface assessment based on videokeratoscopy

Purpose Videokeratoscopy images can be used for the non-invasive assessment of the tear film. In this work the applicability of an image processing technique, textural-analysis, for the assessment of the tear film in Placido disc images has been investigated. Methods In the presence of tear film thinning/break-up, the reflected pattern from the videokeratoscope is disturbed in the region of tear film disruption. Thus, the Placido pattern carries information about the stability of the underlying tear film. By characterizing the pattern regularity, the tear film quality can be inferred. In this paper, a textural features approach is used to process the Placido images. This method provides a set of texture features from which an estimate of the tear film quality can be obtained. The method is tested for the detection of dry eye in a retrospective dataset from 34 subjects (22-normal and 12-dry eye), with measurements taken under suppressed blinking conditions. Results To assess the capability of each texture-feature to discriminate dry eye from normal subjects, the receiver operating curve (ROC) was calculated and the area under the curve (AUC), specificity and sensitivity extracted. For the different features examined, the AUC value ranged from 0.77 to 0.82, while the sensitivity typically showed values above 0.9 and the specificity showed values around 0.6. Overall, the estimated ROCs indicate that the proposed technique provides good discrimination performance. Conclusions Texture analysis of videokeratoscopy images is applicable to study tear film anomalies in dry eye subjects. The proposed technique appears to have demonstrated its clinical relevance and utility.

Risk factors for ocular surface squamous neoplasia recurrence after treatment with topical mitomycin C and interferon alpha-2b

Purpose To determine the rate of recurrence and associated risk factors following the use of mitomycin C (MMC) and/or interferon alpha-2b (IFN) for management of non-invasive ocular surface squamous neoplasia (OSSN). Design Retrospective non-comparative interventional case series. Methods Clinical practice setting of 135 patients treated consecutively with topical MMC (0.4 mg/mL) and/or IFN (1 million units/mL) for OSSN observed for clinical recurrence. Results Clinical recurrences were diagnosed in 19 of 135 (14.1%) eyes following topical treatment. The mean time to recurrence was 17.2 months (range 4 - 61) with 14 (73.7%) recurring within a two year period. There was no greater risk of recurrence identified for variables including lesion size, lesion location, gender, age, treatment type or duration. Post-hoc log-Rank pairwise comparisons revealed that lesions initially treated using surgery alone had significantly reduced time to recurrence (21.1 ± 5.6 months) compared to previous topical treatment with MMC (with or without surgery) (29.6 ± 4.7 months) (p = 0.04) and primary OSSN (23.2 ± 1.8 months) (p = 0.09). Conclusions Topical MMC and IFN are an effective treatment modality for a wide range of non-invasive OSSN. Topical therapy avoids the morbidity of excisional surgery with equivalent or reduced recurrence rates and should be considered as primary therapy.

Research trends of post disaster reconstruction : the past and the future

Natural disasters can have adverse effect on human lives. To raise the awareness of research and better combat future events, it is important to identify recent research trends in the area of post disaster reconstruction (PDR). The authors used a three-round literature review strategy to study journal papers published in the last decade that are related to PDR with specific conditions using the Scopus search engine. A wide range of PDR related papers from a general perspective was examined in the first two rounds while the final round established 88 papers as target publications through visual examination of the abstracts, keywords and as necessary, main texts. These papers were analysed in terms of research origins, active researchers, research organisations, most cited papers, regional concerns, major themes and deliverables, for clues of the past trends and future directions. The need for appropriate PDR research is increasingly recognised. The publication number multiplied 5 times from 2002 to 2012. For PDR research with a construction perspective, the increase is sixfold. Developing countries such as those in Asia attract almost 50% researchers' attention for regional concerns while the US is the single most concentrated (24%) country. Africa is hardly represented. Researchers in developed countries lead in worldwide PDR research. This contrasts to the need for expertise in developing countries. Past works focused on waste management, stakeholder analysis, resourcing, infrastructure issue, resilience and vulnerability, reconstruction approach, sustainable reconstruction and governance issues. Future research should respond to resourcing, integrated development, sustainability and resilience building to cover the gaps. By means of a holistic summary and structured analysis of key patterns, the authors hope to provide a streamlined access to existing research findings and make predictions of future trends. They also hope to encourage a more holistic approach to PDR research and international collaborations.

Kaleidoscope : Reframing learning and teaching evaluation through a shared stakeholder lens

Sector wide interest in Reframe: QUT’s Evaluation Framework continues with a number of institutions requesting finer details as QUT embeds the new approach to evaluation across the university in 2013. This interest, both nationally and internationally has warranted QUT’s collegial response to draw upon its experiences from developing Reframe into distilling and offering Kaleidoscope back to the sector. The word Reframe is a relevant reference for QUT’s specific re-evaluation, reframing and adoption of a new approach to evaluation; whereas Kaleidoscope reflects the unique lens through which any other institution will need to view their own cultural specificity and local context through an extensive user-led stakeholder engagement approach when introducing new approaches to learning and teaching evaluation. Kaleidoscope’s objectives are for QUT to develop its research-based stakeholder approach to distil the successful experience exhibited in the Reframe Project into a transferable set of guidelines for use by other tertiary institutions across the sector. These guidelines will assist others to design, develop, and deploy, their own culturally specific widespread organisational change informed by stakeholder engagement and organisational buy-in. It is intended that these guidelines will promote, support and enable other tertiary institutions to embark on their own evaluation projects and maximise impact. Kaleidoscope offers an institutional case study of widespread organisational change underpinned by Reframe’s (i) evidence-based methodology; (ii) research including published environmental scan, literature review (Alderman, et al., 2012), development of a conceptual model (Alderman, et al., in press 2013), project management principles (Alderman & Melanie, 2012) and national conference peer reviews; and (iii) year-long strategic project with national outreach to collaboratively engage the development of a draft set of National Guidelines. Kaleidoscope’s aims are to inform Higher Education evaluation policy development through national stakeholder engagement, the finalisation of proposed National Guidelines. In correlation with the conference paper, the authors will present a Draft Guidelines and Framework ready for external peer review by evaluation practitioners from the Higher Education sector, as part of Kaleidoscope’s dissemination strategy (Hinton & Gannaway, 2011) applying illuminative evaluation theory (Parlett & Hamilton, 1976), through conference workshops and ongoing discussions (Shapiro, et al., 1983; Jacobs, 2000). The initial National Guidelines will be distilled from the Reframe: QUT’s Evaluation Framework’s Policy, Protocols, and incorporated Business Rules. It is intended that the outcomes of Kaleidoscope are owned by and reflect sectoral engagement, including iterative evaluation through multiple avenues of dissemination and collaboration including the Higher Education sector. The dissemination strategy with the inclusion of Illuminative Evaluation methodology provides an inclusive opportunity for other institutions and stakeholders across the Higher Education sector to give voice through the information-gathering component of evaluating the draft Guidelines, providing a comprehensive understanding of the complex realities experienced across the Higher Education sector, and thereby ‘illuminating’ both the shared and unique lenses and contexts. This process will enable any final guidelines developed to have broader applicability, greater acceptance, enhanced sustainability and additional relevance benefiting the Higher Education sector, and the adoption and adaption by any single institution for their local contexts.

Kaleidoscope : shaping a better future through a stakeholder approach to widespread organisational change

The main focus of ‘Kaleidoscope: Reframing evaluation through a stakeholder approach to sustainable, cultural change in Higher Education’ is to develop a set of principles to guide user-led engagement in widespread organisational change and maximise its impact. The word kaleidoscope represents the unique lens through which each institution will need to view their cultural specificity and local context through an extensive process of collaboration and engagement, followed by communication and dissemination. Kaleidoscope has particular relevance when new approaches to learning and teaching evaluation are introduced by tertiary institutions. Building on the Reframe Project, which involved three years of user-led consultation and was designed to meet stakeholders’ needs, QUT successfully introduced a new evaluation framework in 2013 across the university. Reframe was evidence based, involved scholarly reflection and was founded on a strong theoretical framework. The evolution of the evaluation framework included analysis of scholarly literature and environmental scans across the higher education sector (Alderman, et al., 2012), researched development of conceptual theory (Alderman, et al., in press 2013), incorporated the stakeholder voice and framed within project management principles (Alderman & Melanie, 2012). Kaleidoscope’s objectives are for QUT to develop its research-based stakeholder approach to distil the successful experience exhibited in the Reframe Project into a transferable set of guidelines for use by other tertiary institutions across the sectors. These guidelines will assist others to design, develop, and deploy, their own culturally specific widespread organisational change informed by stakeholder engagement and organisational buy-in. It is intended that these guidelines will promote, support and enable other tertiary institutions to embark on their own projects and maximise the impact. In correlation with a our conference paper, this round table presents the Draft Guidelines and Framework ready for external peer review by evaluation practitioners, as part of Kaleidoscope’s dissemination (Hinton & Gannaway, 2011) applying illuminative evaluation theory (Parlett & Hamilton, 1976), through conference workshops and linked round table discussions (Shapiro, et al., 1983; Jacobs, 2000).

Visibility-related characteristics of crashes involving bicyclists and motor vehicles – Responses from an online questionnaire study

Bicyclists are among the most vulnerable of road users, with high fatal crash rates. Although visibility aids have been widely advocated to help prevent bicycle-vehicle conflicts, to date no study has investigated, among crash-involved cyclists, the kind of visibility aids they were using at the time of the crash. This study undertook a detailed investigation of visibility factors involved in bicyclist-motor-vehicle crashes. We surveyed 184 bicyclists (predominantly from Australia via internet cycling forums) who had been involved in motor vehicle collisions regarding the perceived cause of the collision, ambient weather and general visibility, as well as the clothing and bicycle lights used by the bicyclist. Over a third of the crashes occurred in low light levels (dawn, dusk or night-time), which is disproportionate given that only a small proportion of bicyclists typically ride at these times. Importantly, 19% of these bicyclists reported not using bicycle lights at the time of the crash, and only 34% were wearing reflective clothing. Only two participants (of 184) nominated bicyclist visibility as the cause of the crash: 61% attributed the crash to driver inattention. These findings demonstrate that crash-involved bicyclists tend to under-rate and under-utilise visibility aids as a means of improving their safety.

Influence of drying conditions on the moisture diffusion and fluidization quality during multi-stage fluidized bed drying of bovine intestine for pet food

In order to establish the influence of the drying air characteristics on the drying performance and fluidization quality of bovine intestine for pet food, several drying tests have been carried out in a laboratory scale heat pump assisted fluid bed dryer. Bovine intestine samples were heat pump fluidized bed dried at atmospheric pressure and at temperatures below and above the materials freezing points, equipped with a continuous monitoring system. The investigation of the drying characteristics have been conducted in the temperature range −10 to 25 ◦C and the airflow in the range 1.5–2.5 m/s. Some experiments were conducted as single temperature drying experiments and others as two stage drying experiments employing two temperatures. An Arrhenius-type equation was used to interpret the influence of the drying air temperature on the effective diffusivity, calculated with the method of slopes in terms of energy activation, and this was found to be sensitive to the temperature. The effective diffusion coefficient of moisture transfer was determined by the Fickian method using uni-dimensional moisture movement in both moisture, removal by evaporation and combined sublimation and evaporation. Correlations expressing the effective moisture diffusivity and drying temperature are reported. Bovine particles were characterized according to the Geldart classification and the minimum fluidization velocity was calculated using the Ergun Equation and generalized equation for all drying conditions at the beginning and end of the trials. Walli’s model was used to categorize stability of the fluidization at the beginning and end of the dryingv for each trial. The determined Walli’s values were positive at the beginning and end of all trials indicating stable fluidization at the beginning and end for each drying condition.