Optimization of mixing parameters through a water model for metal matrix composites synthesis

The influence of the mixing parameters on the synthesis of Al–SiCp reinforced metal matrix composites (MMCs) by the stir casting technique is investigated through a water model. The effects of some important mixing parameters such as impeller blade angle, rotating speed, direction of impeller rotation and effect of baffles are investigated and optimized. The results have shown that the axial concentration variation of natural graphite during stirring in the presence of four vertical baffles is 1.0 wt% against in the absence of baffles it is increased to 2.3 wt%. The variations observed in natural graphite concentration in water during mixing are in close agreement with the earlier modeling and limited experimental studies reported on the real molten aluminum–SiC system. Semi-empirical correlations arrived at between the dimensionless numbers for stirred water – natural graphite slurries are Po = Re−0.0545 Fr−1.099 and Po = Re−0.0219 Fr−1.0382 for clockwise and counter clockwise rotation respectively.

Influence of mechanical mixing rates on sludge characteristics and membrane fouling in MBRs

The influence of shear intensity (G) induced by mechanical mixing on activated sludge characteristics as well as membrane fouling propensity in membrane bioreactors (MBRs) was investigated. Four MBRs were operated at different mechanical mixing conditions. The control reactor (MBR0) was operated with aeration only supplemented by mechanical stirring at 150, 300, and 450 rpm in MBR150, MBR300, and MBR450, respectively. It was found that the MBR300 demonstrated minimum rate of membrane fouling. The fouling potential of the MBR300 mixed liquor was lowest characterized by the specific cake resistance and the normalized capillary suction time (CSTN). Moreover, it was found that the mean particle size reduced with an increase in the shear intensity. These results reveal that membrane fouling can be significantly mitigated by appropriate shear stress on membrane fibers induced by mechanical mixing condition.

Surf and turf: music education riding the wave and/or planted firmly in teacher education arts courses across two Australian universities

Tertiary Arts educators are exhorted to offer The Australian Curriculum: The Arts (Dance, Drama, Media Arts, Music and Visual Arts) in their teacher education programs. This paper situates itself across two interstate universities (Deakin in Victoria and Griffith in Queensland) where both authors are music educators at these institutions. They discuss the two different ways that primary Arts education is offered at their universities by focusing on the Bachelor of Primary course (program/degree). The focus at Griffith University is on integrating the Arts whereas at Deakin University, the Arts are taught as a discipline within the unit (subject). Across both universities two teaching units for primary Arts education is core within the four-year program. Drawing on the author’s narrative reflection, observation, student questionnaire data, anecdotal feedback and student end of semester evaluations we discuss two different methods of delivery, assessment and challenges the units present to the authors and students. Though tertiary Arts educators are challenged to be inclusive of a rich and diverse arts curriculum as music educators we question whether the students are merely surfing the crest of the wave or being firmly planted in the ground to effectively implement music education in their future primary classrooms. We invite dialogue with other music educators who face similar situations where the delivery of music education is not located within the Arts and is dependent on staffing, resourcing and time limits and in some situations is almost drowning.