The COVID‐19 crisis and complexity: A soft systems approach

The COVID‐19 pandemic is a crisis with high complexity and should be understood as such by scholarship. A complexity science approach situates increasingly divergent ideological and epistemological perspectives about the crisis within the practical exigencies of containment and mitigation measures. We ask which of the seven stages of soft systems methodology contributes to deeper understandings about COVID‐19 as a policy issue, beyond the contributions of current and conventional perspectives. The discussion outlines implications for practice and places them within broader debates about tensions between scientific facts and political values.     

Biocatalytic electrode improvement strategies in microbial fuel cell systems

Microbial fuel cells (MFCs) produce electricity as a result of the microbial metabolism of organic substrates, hence they represent a sustainable approach for energy production and waste treatment. If the technology is to be implemented in industry, low cost and sustainable bioelectrodes must be developed to increase power output, increase waste treatment capacity, and improve service intervals. Although the current application of abiotic electrode catalysts, such as platinum and electrode binders such as Nafion leads to greater MFC performance, their use is cost prohibitive. Novel bioelectrodes which use cost effective and sustainable materials are being developed. These electrodes are developed with the intention to reduce start-up time, reduce costs, extend life-span and improve core MFC performance metrics (i.e. power density, current density, chemical oxygen demand (COD) reduction and Coulombic efficiency (CE)). Comparison of different MFC systems is not an easy task. This is due to variations in MFC design, construction, operation, and different inocula (in the case of mixed-culture MFCs). This high intra-system variability should be considered when assessing MFC data, operation and performance. This review article examines the major issues surrounding bioanode and biocathode improvement in different MFC systems, with the ultimate goal of streamlining and standardising improvement processes. © 2018 Society of Chemical Industry     

Impact of graphite impurities on the structure and optical properties of the sodium borate oxide glass

For the carbon-based glass fabrication/manufacture process, different amounts of pure graphite powder were added up to 100 wt.% of sodium tetraborate oxide (the weight of one mole of the sodium tetraborate is 381.372 g/mol) and then melted at 950 °C for 2 h before fast quenching in the air at RT. The resulted solids were examined by the XRD and SEM techniques, which confirmed the amorphous natures for studied samples. FTIR spectroscopy showed that some C-atoms are shared in the glass network as C–O and CO₂. In contrast, the UV–Vis showed that the increase in the graphite contents/impurities causes a red shift in the value of the optical edge and the value of Fermi energy. Also, the increase of the graphite impurities causes a decrease in the bandgap values of both direct and indirect electronic transitions. Both the values of Urbach energy and the metallization indicated an increase in the crystallinity degree as the graphite content increase. A graphite-based glass is a promising material for wide-scale applications.

     

Effect of exchanging PbO with NiO on the structure and optical parameters action of some lanthanum borate oxide glasses

Journal of Materials Science: Materials in Electronics - This work is an attempt to estimate the effect of the exchanging of PbO with NiO on the optical and structural parameters for some...     

Extrusion of silicon-rich AlMgSi alloys

As a part of on-going research on phase transformations during the deformation of light alloys, the effect of silicon excess on the extrudability and mechanical properties of the standard AlMgSi1 alloy within AA6082 alloy is investigated in this study. The AlMgSi1 alloy and three experimental aluminum alloys with a silicon content of 1.98%, 3.73% and 5.51% were direct-chilled cast into billets 95 mm in diameter, homogenized at 540 °C for 4 h and extruded into 12 mm diameter rods at different extrusion speeds. The results showed that an increase in the silicon content reduced the extrudability of the AlMgSi1 alloy by lowering the limiting extrusion speed. However, the extruded alloys with 3.73% and 5.51% silicon, generally characterized by a fine grained microstructure, exhibited higher strength levels compared with the 1.98% silicon alloy. Nonetheless, the mechanical properties of these alloys, in the T6 temper condition, were below those of the AlMgSi1 base alloy.     

Debiasing overoptimistic beliefs about braking capacity

We investigated, using questionnaires, different strategies for removing drivers’ overoptimism (Svenson et al., 2012a) about how fast their speed could be decreased when they were speeding compared with braking at the speed limit speed. Three different learning groups and a control group made collision speed judgments. The first learning group had the distance a car travels during a driver's reaction time for each problem. The second group had this information and also feedback after each judgment (correct speed). The third group judged collision speed but also braking distance and received correct facts after each problem. The control group had no information at all about reaction time and the distance traveled during that time. The results suggested the following rank order from poor to improved performance: control, group 1, group 3 and group 2 indicating that information about distance driven during a driver's reaction time improved collision speed judgments and that adding stopping distance information did not add to this improvement.