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Investigating the charge storage mechanisms in electrochemical capacitors: separating faradaic and non-faradaic processes using step potential electrochemical spectroscopy
No full textIn this work a new method for characterising the charge storage mechanisms in electrochemical capacitors has been developed. This technique, step potential electrochemical spectroscopy (SPECS), has been used to separate the capacitive contributions from faradaic and non-faradaic charges storage processes in a range of electrode materials. Activated carbon electrodes in aqueous electrolytes were analysed and shown to exhibit significant pseudo-capacitive behaviour which can be attributed to redox active functional groups and decomposition of the electrolyte at the anodic or cathodic potential limits. The charge storage behaviour was examined as a function of scan rate and was found to transition from predominantly double layer capacitive behaviour at high scan rates to battery-like behaviour, characterised by significant pseudo-capacitance contributions, at low scan rates. A range of manganese dioxide electrodes with different material properties have been studied to examine the effects that material composition, structure and morphology have on the performance of these materials as electrochemical capacitor electrodes. The relationships between each of the contributions to total capacitance and the material properties have been identified. The charge storage mechanism has been shown to transition from predominantly pseudo-capacitive behaviour to predominantly double layer behaviour as the scan rate is increased. The relative contributions from each of these processes to the overall specific energy and power of each manganese dioxide samples has been analysed and related to the properties of each material
Nanoparticle effects on partial and complete oxidation of isobutane over metal oxide catalysts
No full textGold nanoparticles, derived from preformed n-alkanethiolate-stabilised gold nanoparticles, have been supported on metal oxide catalysts and pyrovanadates for the complete oxidation of isobutane and the oxidative dehydrogenation of isobutane to isobutene, respectively. The initial adsorption of gold nanoparticles on metal oxides depends on the length of the alkyl carbon chain and the surface area of the metal oxide, and also forms alkyl-sulfoxide and -sulfone species. On thermolysis (340°C) to decompose the organic alkylthiolate ligands, residual adsorbed sulfate (0.2-0.3 wt%) remains on the catalyst surface. TEM/STEM studies have shown that the sizes of gold nanoparticles, originally 1.8-2.0 nm, increase in diameter following adsorption and thermolysis. This depends on the surface area of the support. n-Hexanethiolate-stabilised gold nanoparticles were used to obtain 5 wt% Au nanoparticles supported on β-MnO₂, α-Fe₂O₃, Co₃O₄ and NiO. The oxides, with and without gold nanoparticles, were investigated for the complete oxidation of isobutane. Some effect from residual sulfate was detected, although this depended on the metal oxide. TEM/STEM and XRD studies were used to monitor the sizes of the gold nanoparticles, which were 2-4 nm in size. Analogous studies, with and without gold nanoparticles, on supported metal oxides of the type MOx/γ-Al₂O₃ and MOx/CeO₂ (M = Mn, Fe, Co, Ni), were studied for the complete oxidation of isobutane. Gold 4f XPS studies showed that it was likely that gold nanoparticles were the key to the oxidation catalysis and not any higher oxidation states of gold. The transition metal pyrovanadates, M₂V₂O₇ (MII = Mn, Co, Ni, Cu and Zn), again with and without gold nanoparticles (5 wt%) have been investigated for the oxidative dehydrogenation of isobutane to isobutene from 300-450°C under reducing conditions (isobutane:O₂ = 20:1). Pyrovanadate reduction occurred to produce V(IV) and/or V(III) products that depended on the identity of M(II) and the presence of gold nanoparticles. The conversions reached as high as 11% and 16% in the absence and presence of gold nanoparticles, and the selectivities to isobutene were as high as 40-50%. Gold 4f XPS studies showed that the highest yields of isobutene correlated with a lower Au(I) content. Co₂VO₄ and ZnV₂O₄ were also found to be active catalysts for
this reaction
Perceptions of second year nursing students on the relevance of science in nursing
No full textPrompted by the observations made while teaching bioscience to nursing students, the researcher undertook a survey to identify the perceptions of second year nursing students on the relevance of science in nursing. The three part questionnaire developed by the researcher addressed the general characteristics of the respondents and their responses to a series of science-related statements. Personal comments relating to the topic could be made if desired. The questionnaire was refined by cross-checking with existing tools and consulting with experts in nursing, science and teaching. A pilot study established face and construct validity and identified necessary modifications. The main study was administered to 182 second year nursing students with a response rate of 60% (n=109). An SPSS database and analysis of emergent themes were utilised to analyse the data. Data analysis revealed that although respondents believe science to be inherently valuable and relevant to nursing, the subject was not necessarily being taught in a way that enabled students to grasp the relevance of scientific concepts to clinical practice
Ischemic penumbra as a trigger for intracranial pressure rise: a potential cause for collateral failure and infarct progression?
No full textWe have recently shown that intracranial pressure (ICP) increases dramatically 24 hours after minor intraluminal thread occlusion with reperfusion, independent of edema. Some of the largest ICP rises were observed in rats with the smallest final infarcts. A possible alternate mechanism for this ICP rise is an increase of cerebrospinal fluid (CSF) volume secondary to choroid plexus damage (a known complication of the intraluminal stroke model used). Alternatively, submaximal injury may be needed to induce ICP elevation. Therefore we aimed to determine: i. if choroid plexus damage contributes to the ICP elevation; ii. If varying the patency of an important internal collateral supply to the middle cerebral artery (MCA), the anterior choroidal artery (AChA), produces different volumes of ischemic penumbra iii. if presence of ischemic penumbra (submaximal injury) is associated with ICP elevation. We found: i. no association between choroid plexus damage and ICP elevation; ii. animals with a good internal collateral supply through the AChA during MCAo had significantly larger penumbra volumes; iii. ICP elevation at ≈24 hours post-stroke only occurred in rats with submaximal injury, shown in 2 different stroke models. We conclude that active cellular processes within the ischemic penumbra may be required for edema-independent ICP elevation
Towards the development of processable molecular imprinted polymers
No full textThe synthesis of processable core crosslinked star (CCS) polymers via iniferter and RAFT mediated radical polymerisation has been investigated for their potential application in the field of molecular recognition. Molecular imprinted CCS polymers have potential as delivery systems in solution and, by virtue of its improved processability, may be used to produce thin films with recognition capability for sensing applications. Synthesis of CCS polymers, consist of poly(ethylene glycol dimethacrylate) core and polystyrene (PS) arms, via the arm-first method proved to be more straightforward than the core-first method. The length of the PS arm could be controlled by varying the ratio of styrene monomer to the iniferter or RAFT agent and polymerisation time. Although lower polydispersity (PDI) of PS arms were produced via RAFT (PDI values between 1.2 – 1.6) compared to those of the iniferter (PDI values between 1.8 – 12.2), synthesis of arm-first CCS polymers via iniferter was more successful than RAFT. Synthesis of CCS polymers via the core-first method was deemed more suitable for the preparation of molecular imprinted CCS since the imprinted core can be accessed for a more comprehensive characterisation and, unlike the CCS via arm-first, there is no contamination from unreacted PS arms. CCS molecular imprinted polymers (MIPs) were synthesised employing the core-first method. The molecular imprinted microspheric cores were prepared using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as crosslinker at various concentrations of iniferter/RAFT (i.e. 5, 10 and 20 mol % with respect to the total monomer) in the presence of benzylpiperazine (BZP) as template. The large difference in size between the MIPs and their NIP counterparts, which translated to a large difference in the specific surface areas of the microspheres, has implications on the assessment of binding efficiency generally normalised against NIPs with respect to mass. Therefore, the binding efficiency of the MIPs was also expressed with respect to specific surface area. Among the formulations, MIP microspheres prepared with 5% BDDC and MCEBTTC exhibited the best binding performance in their respective series, with BDDC MIP cores exhibiting higher binding capacity and greater specific binding compared to the RAFT MIPs. Further investigation revealed that the 5% BDDC MIP exhibited higher maximum number of binding sites (N) and greater high affinity binding sites (about 90% and 2.5-fold higher, respectively) as well as stronger affinity towards the BZP template (lower Kd value) compared to those of the 5%RAFT MIP. Selectivity studies were carried out on the 5% BDDC MIP against 1-phenylpiperazine (PHP) and (1R,2S)-(-)-ephedrine (EPH) having closely related structures to that of BZP. The MIP exhibited better selectivity towards BZP over PHP but better selectivity towards EPH over BZP in the non-competitive binding environment. In the competitive binding environments, the MIP exhibited better selectivity towards BZP over PHP but showed equivalent selectivity towards both BZP and EPH, which was attributed to the smaller size and stronger hydrogen bonding ability of EPH compared to BZP. Several fractions of CCS MIPs, which differ in their degree of dispersibility in THF, were obtained when polystyrene (PS) arms were grafted to 5% BDDC MIP. Our results show that dispersibility improved with increasing arm length, although it did not necessarily contribute to better binding performance. The presence of PS arms around the imprinted core resulted in a decrease in binding capacity of the CCS MIPs compared to the core precursor in acetonitrile, a bad solvent for the arm. Similar results are obtained in THF, a good solvent for the PS arm. However, contrary to the binding results in acetonitrile where binding capacity seemed to decrease with increasing arm length, greater binding capacity was exhibited by the CCS MIPs with longer arms than those with shorter arms in THF. In this study, we have demonstrated that processability of MIP microspheres can be readily introduced by attaching linear polymeric arms. However, it was difficult to obtain comprehensive binding assessment using the conventional comparison of the MIP with the NIP due to the presence of difference number and/or arm length around the CCS polymers.</p
Factors influencing the physiological and perceptual decision-making demands of Australian football field umpires
No full textTeam sport officials are an essential component of sport to ensure a fair and safe competition by enforcing the laws of the game. Some team sport officials (including but not limited to Australian football, soccer, rugby league and rugby union) have been referred to as “interactor” officials (MacMahon et al., 2014). Interactors are suggested to have “high interaction and physical movement demands and often a large number of cues to process” (MacMahon et al., 2014). These interactor officials are often exposed to extensive physical demands to maintain an ideal position around play to make perceptual judgements, based upon the actions of the players. Both the physical and perceptual decision-making tasks are performed simultaneously to apply the laws of the game. Despite this dual-task requirement of match play, the physical and perceptual decision-making training methods are typically applied in isolation, which fails to provide ecologically valid training strategies. Therefore, the overall aim of this thesis was to observe the physical and perceptual decision-making demands of match play and examine the effects of combined training methods to best replicate the match environment. An examination of the specific match demands of elite Australian football (AF) umpires has remained relatively unknown. No data have detailed the free kick decision-making performance of an umpire during match play, despite this being considered his/her primary role. Of further interest, the physical demands of different field umpire positions (mid-zone or end-zone) are yet to be examined. Therefore, to quantify the overall match demands of AF umpiring, 29 elite AF field umpires (age: 32.4 ± 6.1 yr; height: 181.7 ± 5.7 cm; body mass: 73.6 ± 5.4 kg) were assessed during 20 Australian Football League (AFL) matches (Study 1). Time-motion analysis data was collected from 5 Hz MinimaxX global positioning system (GPS) devices, and free kick decision-making accuracy was assessed by elite umpire coaches following each match. [More detail in thesis abstract]. Overall, 44 ± 8 free kicks were awarded throughout a match, at an accuracy of 84 ± 6%. The number of free kicks awarded and decision-making accuracy (% correct) were consistent (p > 0.05) across quarters. Separately, the results show that despite reductions in the physical demands following the first quarter, decision-making accuracy is maintained throughout a match. Therefore, decision-making performance was not directly compromised by the intermittent running demands that were completed by the AF umpires. The reduced physical demands of the end-zone (compared to the mid-zone) position allow for some physical recovery between bouts within the mid-zone, and these rotations permit the match demands are shared amongst all umpires. As such, the results of Study 1 provide current information regarding the physical and perceptual decision-making requirements of elite field umpires within AFL match play. In addition to Study 1, there is limited data available on sub-elite AFL umpires and comparison of the demands of elite and sub-elite AF umpires is important to compare the performance characteristics between the two levels of competition. Sub-elite AF competitions are vital for the development of umpire skills in their progression towards officiating elite match play. It is however unknown if these matches adequately prepare sub-elite umpires for the requirements of elite competition. Study 2 aimed to compare the physical and decision-making demands of elite and sub-elite competition. During 27 matches, time-motion analysis and free kick decision-making performance as described in Study 1 were examined for 36 AF umpires (elite: n = 29, age: 32.4 ± 6.1 yr, height: 181.7 ± 5.7 cm, body mass: 73.6 ± 5.4 kg; sub-elite: n = 7, age: 23.2 ± 2.3 yr, height: 178.2 ± 11.3 cm, body mass: 70.9 ± 7.3 kg). Significant differences (p 0.05). In addition, the movement speed at the time of a decision had no effect on decision-making (p > 0.05). However, the running speed immediately prior to incorrect decisions was significantly higher (p < 0.05) than for correct decisions. These findings demonstrate that while there is no effect of distance from play or instantaneous velocity on decision-making accuracy, a higher running speed prior to a decision increases the likelihood of a decisional error. As such, superior anticipatory skills that would reduce the running demands prior to a decision may improve the decision-making accuracy of umpires. Despite the knowledge of the physical and physiological demands of interactor sports officials, little is known as to the relationship of these demands with decision-making performance, during intermittent exercise typical of field-based team sport competition. Numerous laboratory-based studies have suggested that upon the onset of exercise, psychomotor performance continues to improve during steady state and incremental exercise before decreasing at higher exercise intensities, yet limited data is available for intermittent exercise. As such, the purpose of Study 4 was to examine changes in psychomotor performance of interactor sports officials during a laboratory-based match simulation. Twelve elite interactor sports officials (age: 32.5 ± 5.5 yr; height: 180.0 ± 6.8 cm; body mass: 78.8 ± 7.6 kg) completed an intermittent match simulation on a non-motorised treadmill, while repeatedly completing a psychomotor task (Eriksen Flanker). Significant reductions (p < 0.05) in physical performance measures were observed towards the end of the simulation, however psychomotor performance was maintained throughout. However [more detail in thesis abstract]. Collectively, it appears that interactor sports officials can maintain their psychomotor performance through a laboratory simulation, despite reductions in the physical performance measures. Further, short duration bouts of HSR may promote psychomotor performance during intermittent exercise; possibly due to changes in central nervous system (CNS) arousal and cerebral blood flow (CBF) because of the increased running speed. Finally, the aim of Study 5 was to examine the effects of a combined high-intensity interval training (HIIT) and psychomotor training program on performance during an intermittent laboratory protocol. Ten sub-elite interactor sports officials (age: 22.5 ± 4.1 yr; height: 181.8 ± 8.3 cm; body mass: 75.7 ± 9.7 kg) initially completed a match simulation on the non-motorised treadmill (like that used in Study 4). Based on individual psychomotor performance, participants were placed either in a psychomotor training (n = 5) or physical conditioning (n = 5) group. Both groups completed a 6-week HIIT program (2 sessions per week; 4 sets of 3 or 4 min running efforts @ 90-95% maximum heart rate), with the psychomotor training group completing additional psychomotor training during the 3 min inter-interval recovery periods. Significant improvements (p < 0.05) were identified in maximal oxygen consumption (V̇O₂max) and velocity at V̇O₂max for both groups. Magnitude-based inferences suggest that the combined psychomotor and physical conditioning program provided a beneficial effect on psychomotor performance during and following the match simulation. The outcomes of the current study present a framework for the application of replicating the match environment for the acquisition of psychomotor skill of interactor sport officials. Collectively, these findings demonstrate the extensive physical and perceptual decision-making demands of AF umpires during match play. A considerable gap exists between elite and sub-elite umpires free kick decision-making accuracy thus highlighting the importance of developing decision-making performance through training. Further, traditional training methods used within interactor sports officials typically isolate the physical and decision-making aspects and as a result, they do not replicate the match demands. Overall, the findings of this thesis highlight the physical and decision-making demands of interactor sports officials and provides a potential framework for the development of training strategies to replicate the physical and perceptual decision-making demands of match play
The original bishops: office and order in the first Christian communities (book review)
No full textReview of The Original Bishops: Office and Order in the First Christian Communities by Alistair C. Stewart
A 3-DOF SOI MEMS ultrasonic energy harvester for implanted devices
No full textThis paper reports the design and testing of a microelectromechanical systems (MEMS) energy harvester that is designed to harvest electrical energy from an external source of ultrasonic waves. This mechanism is potentially suited to applications including the powering of implanted devices for biomedical applications. The harvester employs a novel 3-degree of freedom design, with electrical energy being generated from displacements of a proof mass via electrostatic transducers. A silicon-on-insulator MEMS process was used to fabricate the device, with experimental characterization showing that the harvester can generate 24.7 nW, 19.8 nW, and 14.5 nW of electrical power respectively through its x-, y-, and z-axis vibrational modes
Business ethics education and faculty teaching expertise: are business school educators equipped, trained and capable to teach normative ethical theory?
No full textBusiness schools are increasingly introducing the teaching of ethics into their academic programs and in particular to MBA’s, partially in response to recent business scandals. Nevertheless, the overwhelming trend is to teach ethics within another subject rather than as a compulsory and stand-alone subject. The reason is partially because empirical researches into the effectiveness of business ethics education do not reach uniform conclusions. A portion of studies have found that ethics education is ineffective and therefore concluded that ethics cannot be taught. However, there is a growing call to investigate variables that were never explored in these studies, and in particular: the subject knowledge of the educators and their teaching methods. Therefore, in response to that call, this study sought to find out if currently employed business school educators have an appropriate level of knowledge in the subject of normative ethical theory, and if any particular variable increases an educator’s level of teaching expertise for teaching ethics. This quantitative study surveyed 128 academics that teach ethics to business students in 29 Australian universities in order to test their ability to teach ethics effectively. It found that academics, highly educated in business and management but who have themselves not studied ethics as a stand-alone subject, do not have a reasonable understanding of normative ethical theory and concluded that they are therefore unlikely to be able to teach ethics successfully. It found that an overwhelming majority of business school educators are not equipped, trained or capable to teach ethics to business students. However, it also found that educators who had themselves been taught ethics as a stand-alone subject did have a reasonable understanding of ethics theory and therefore concluded that there is a higher likelihood that ethics can be taught effectively if it is taught by educators who themselves have studied ethics, critical thinking or philosophy as a stand-alone subject
How should debriefing be undertaken in web-based studies?: findings from a randomized controlled trial
No full textBackground: Internet research may raise older ethical issues in new forms or pose new issues. It has been recommended that debriefing information online be kept very short, with further information including study results made available if requested by participants. There are no empirical studies that compare possible alternative methods of debriefing in online studies. Objective: To undertake a randomized controlled trial evaluating how to implement the recommended approach by assessing the effects of two different approaches on accessing of additional information. Methods: All 11,943 participants in the Effects of Study Design and Allocation (ESDA) study, which employed deception, were randomly assigned to one of two methods of debriefing: Group A received the debriefing information in the body of an email with links to protocol and results pages; Group B was presented with these links after clicking on an initial link in the body of the email to view the debriefing information on a website. Outcomes assessed were the proportions clicking on the links to the protocol and results summary and the time spent on these pages by those accessing them. Results: The group who were presented with no debriefing information in the body of the email and went to a website for this information (Group B) were approximately twice as likely to subsequently access the protocol and the results summary. These differences between the two groups were highly statistically significant. Although these differences are clear, the overall proportions accessing such information were low, and there were no differences in mean time spent reading these pages. Only one quarter of Group B actually accessed debriefing information.
Conclusions: In circumstances where the uptake of fuller information on study design, methods, and findings is deemed important, debriefing information may be better provided via a link and not included in the body of an email. Doing so may, however, reduce the extent of receiving any debriefing information at all. There is a wider need for high quality empirical studies to inform ethical evaluations. Trial Registration: Australian New Zealand Clinical Trials Registry, ACTRN12610000846022 (http://www.anzctr.org.au/