Synthesis and optimisation of IrO2 electrocatalysts by Adams fusion method for solid polymer electrolyte electrolysers

IrO2 as an anodic electrocatalyst for the oxygen evolution reaction (OER) in solid polymer electrolyte (SPE) electrolysers was synthesised by adapting the Adams fusion method. Optimisation of the IrO2 electrocatalyst was achieved by varying the synthesis duration (0.5 – 4 hours) and temperature (250 - 500°C). The physical properties of the electrocatalysts were characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction (XRD). Electrochemical characterisation of the electrocatalysts toward the OER was evaluated by chronoamperometry (CA). CA analysis revealed the best electrocatalytic activity towards the OER for IrO2 synthesised for 2 hours at 350oC which displayed a better electrocatalytic activity than the commercial IrO2 electrocatalyst used in this study. XRD and TEM analyses revealed an increase in crystallinity and average particle size with increasing synthesis duration and temperature which accounted for the decreasing electrocatalytic activity. At 250°C the formation of an active IrO2 electrocatalyst was not favoured

Optimization of gas diffusion electrode for polybenzimidazole-based high temperature proton exchange membrane fuel cell: Evaluation of polymer binders in catalyst layer

Gas diffusion electrodes (GDEs) prepared with various polymer binders in their catalyst layers (CLs) were investigated to optimize the performance of phosphoric acid doped polybenzimidazole (PBI)-based high temperature proton exchange membrane fuel cells (HT-PEMFCs). The properties of these binders in the CLs were evaluated by structure characterization, electrochemical analysis, single cell polarization and durability test. The results showed that polytetrafluoroethylene (PTFE) and polyvinylidene difluoride (PVDF) are more attractive as CL binders than conventional PBI or Nafion binder. At ambient pressure and 160 o C, the maximum power density can reach w 0.61 W cm-2 (PTFE GDE), and the current density at 0.6 V is up to ca. 0.52 A cm-2 (PVDF GDE), with H2/air and a platinum loading of 0.5 mg cm-2 on these electrodes. Also, both GDEs showed good stability for fuel cell operation in a short term durability test.Web of Scienc

Management of ICT in education: A meta-study on the local (South African and International research landscape

Despite early optimism, the benefits and impact of information and communication technology investments in education have not been successfully noticeable to date. This is particularly challenging in view of the continual global pressure for the digitisation of education. This paper addresses the quantifiable array of research on the management of information and communication technology in education (MICTED). Articles published between January 2010 and December 2014 in ten free, open-source, peer-reviewed electronic journals were collected to ascertain current research trends on MICTED. Through a meta- analysis a representative sample was obtained that enabled generalisation across local and international boundaries on the MICTED. A humanist approach was used to develop post- priori quantitative analysis. The data indicates a vacuity in research on MICTED. A need for empirical research on MICTED exist that will inform and guide all role players in the South African education and global context on the implementation, use and sustainability of ICT in education

Management of penetrating neck injuries

Background: Routine surgical exploration after penetrating neck injury (PNI) leads to a large number of negative neck explorations and potential iatrogenic injury. Selective non-operative management (SNOM) of PNI is gaining favour. The present study assessed the feasibility of SNOM in PNI. Methods: Seventy-seven consecutive patients with PNI presenting to a tertiary trauma centre were included in this prospective study from September 2009 to December 2009. All patients were managed according to Advanced Trauma Life Support guidelines, and either underwent emergency surgery or were managed without surgery, based on clinical presentation and/or outcome of special investigations. Results: Eight patients (10 per cent) were haemodynamically unstable at presentation. Foley catheter balloon tamponade (FCBT) was successful in stopping active bleeding in six of these patients, and diagnostic angiography revealed an arterial injury in five. The remaining 69 patients were managed using SNOM. Angiography or computed tomography was done in 41 patients (53 per cent), and showed arterial injury in 15. These injuries were treated surgically (7 patients), radiologically (stenting in 3) or conservatively. Contrast swallow and/or endoscopy were performed in 37 patients (48 per cent) for suspected oesophageal injury, but yielded no positive results. During follow-up no missed injuries were detected. Conclusion: FCBT was useful in patients with PNI and active bleeding. Stable patients should undergo additional investigation based on clinical findings only. Copyrigh

Type VI secretion: a beginner's guide

Type VI secretion is a newly described mechanism for protein transport across the cell envelope of Gram-negative bacteria. Components that have been partially characterised include an IcmF homologue, the ATPase ClpV, a regulatory FHA domain protein and the secreted VgrG and Hcp proteins. Type VI secretion is clearly a key virulence factor for some important pathogenic bacteria and has been implicated in the translocation of a potential effector protein into eukaryotic cells by at least one organism (Vibrio cholerae). However, type VI secretion systems (T6SSs) are widespread in nature and not confined to known pathogens. In accordance with the general rule that the expression of protein secretion systems is tightly regulated, expression of type VI secretion is controlled at both transcriptional and post-transcriptional levels

Towards Overcoming Millennial Classroom Barriers: Reflections from Engineering Students on Blended Teaching and Learning Innovations

A proposition for the use of a blended teaching and learning approach maintains that(a)ease of access  and  flexibility,(b)an increase in  the  degree of  active  learning,  and  (c) an improvement  in  learning experiences  and learning outcomes for  students  are  expected accomplishments to  implementation success. In  this  paper,  we  present  an  analysis  of  how  a blended  teaching  and  learning  approach  influenced  the  experiences  of engineering faculty students.  Our  empirical  analysis  found  that  a  blended  teaching  and  learning  approach  is students’ preferred teaching strategy, and traditional face-to-face teaching strategies alone are no longer sufficient for achieving success with new generation engineering students. Further, we  show  how the  blended  teaching  and  learning  approach  can  enhance  understanding  of engineering knowledge and support students who would otherwise lag behind. We also show how active  support from faculty management enhances the  implementation subtleties and advance  the  development of  a  dynamic  pedagogy. Our  findings  offer  lecturers  important insights into students’ preferences, as well a show lecturers can endorse and design a teaching and learning approach that is agile and adaptable, meeting the challenges of the environment in which they are working, which is similarly in endless flu

Technological Advances in Winery Wastewater Treatment: A Comprehensive Review

The commercial production of wine is directly linked to the use of large amounts of fresh water coupledwith the generation of copious amounts of wastewater containing significant amounts of organic andinorganic substances. The impact of this waste stream on the environment has required the wine industryto implement certain protocols in wastewater management to comply with respective effluent dischargeregulations as set out by local authorities. Reduced accessibility to good quality water resources in recentyears has forced wineries to consider more efficient wastewater management strategies to improve waterrecovery and re-use, thereby promoting more sustainable wine production and minimizing the impact onstressed water resources. This review presents a comprehensive overview of established and emerging,physicochemical, biological, advanced oxidation and hybrid wastewater treatment technologies specificallyapplicable to the wine producing industry. Herein, winery wastewater composition and treatmenttechniques, environmental implications, knowledge gaps, technological operational challenges, alternativedisposal and recycling options of treated winery wastewater are critically evaluated

Membrane electrode assemblies with low noble metal loadings for hydrogen production from solid polymer electrolyte water electrolysis

High performance membrane electrode assemblies (MEAs) with low noble metal loadings (NMLs) were developed for solid polymer electrolyte (SPE) water electrolysis. The electro- chemical and physical characterization of the MEAs was performed by IeV curves, elec- trochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Even though the total NML was lowered to 0.38 mg cm-2, it still reached a high performance of 1.633 V at 2 A cm-2 and 80 o C, with IrO2 as anode catalyst. The influences of the ionomer content in the anode catalyst layer (CL) and the cell temperature were investigated with the purpose of optimizing the performance. SEM and EIS measurements revealed that the MEA with low NML has very thin porous cathode and anode CLs that get intimate contact with the electrolyte membrane, which makes a reduced mass transport limitation and lower ohmic resistance of the MEA. A short-term water electrolysis operation at 1 A cm-2 showed that the MEA has good stability: the cell voltage maintained at ~1.60 V without distinct degradation after 122 h operation at 80 o C and atmospheric pressure.Web of Scienc