Margaret Jollands

Project-based learning as a contributing factor to graduates’ work readiness

This paper explores what work readiness means for two cohorts of graduate engineers, one from a traditional curriculum, the second from a largely project-based curriculum. Professional bodies and employers have defined a set of attributes for engineering graduates so that graduates will be ‘work ready’. Problem-based learning (PBL) is claimed to be a suitable approach to develop such skills. The graduates were interviewed some months after starting work, along with their managers. All the graduates recognised the benefits of taking PBL subjects as well as vacation work, with success in communication attributed more to PBL. Both cohorts had similar learning outcomes, high skill levels in project management, problem solving, communication skills, research and sustainability. A skills gap in ethics was identified for both cohorts of graduates and their managers. Further work is planned to link skill development with undergraduate learning experience.

Influence of phase structure on impact toughening of isotactic polypropylene by metallocene-catalyzed linear low-density polyethylene

In the present study isotactic polypropylene (PP) and metallocene-catalyzed linear low-density polyethylene (mLLDPE) were blended together to obtain thermoplastic materials (compositions) with improved toughness. Structure-property relationships were determined for these compositions with the help of scanning electron microscopy (SEM). Special emphasis was made on tracing the morphological features that led to the optimum mechanical performance. A co-continuous type of structure was found to have much superior toughness as compared to a dispersed-matrix structural type, for blends comprised of the same components (PP and mLLDPE). The study showed the fascinating possibility of creating toughened PP blends by inducing a co-continuous structure.

Miscibility Studies on cross-linked EVA/LLDPE Blends by TMDSC

Cross-linked polymers have particular rheological responses during reprocessing, e. g. if the material is recycled, special processing conditions are required. Other virgin polymers can be used as a blending component to enhance rheological properties.Bi-layer film of EVA/LLDPE was produced on a blown film line and cross-linked by high-energy radiation. This film was ‘agglomerated’ then reprocessed in a twin-screw extruder with virgin LLDPE and blown into film. The miscibility of the blend components was then studied using a TA Instruments temperature modulated differential scanning calorimeter (TMDSC).It was found that the cross-linked EVA/LLDPE scrap and the LLDPE have a slight miscibility in the liquid state. A bigger portion of LLDPE was miscible (dissolved) in EVA in low LLDPE blends. A positive deviation in the heat capacity of the LLDPE component compared to the additivity rule indicated melting to be more reversible in the first heating cycle. This initial miscibility was attributed to being induced by high shear during processing. A smaller positive deviation also occurred in the second heating cycle. This was attributed to intrinsic miscibility.

Crystallinity of polypropylene-silica ash composites affected by the mixing conditions - DSC studies

For particulate polymeric composites, mixing is a crucial step to be optimised; and in the process-control stage, identification of the factors that influence mixing is important for a deeper understanding of the composite mechanical performance. A mixing study of a hydrophobic polymer matrix (polypropylene) filled with a hydrophilic particulate-filler (silica from rice husk ash) was carried out using a batch mixer at a constant filler fraction of 20% (w/w). The study involved varying the mixing-time, screw speed and mixing-chamber temperature used to prepare the composites. Mechanical analysis of the samples showed that the tensile strength and modulus values were dependent on the mixing conditions. Furthermore, DSC studies of the samples revealed that the degree of crystallinity was also affected by the mixing conditions. The observed increase in the tensile strength was attributed to the increased filler-matrix interactions; however, there was difficulty in analysing how the mixing conditions influenced the tensile strength because of a lack of extensive data on filler dispersion. The increase in crystallinity, as affected by mixing conditions, was thought to improve the filler-matrix interaction leading to an increased tensile modulus. Interestingly, samples showed permanent morphological changes after their previous thermal histories were erased, suggesting that there was significant interaction between the silica ash particles and the polymer matrix, even though they are quite incompatible. A statistical analysis based on the tensile data was carried out to optimise the state of mixing. The results indicate that (i) the optimised state of mixing correlated with higher crystallinity and (ii) changes in the parameters of physical mixing might significantly affect the homogeneity and crystallinity, both of which are related to the mechanical performance of the composites. Furthermore, reducing the particle size of the silica ash was also found to increase the crystallinity, which was in turn related to the improved tensile properties of the composites. The investigation attempts to highlight that for apparent incompatible system, homogeneity is very important but it alone cannot explain the moderate filler-matrix interactions and filler bonding characteristics that are known to contribute to improved tensile properties. Somehow, composites mechanical properties are improved by optimising the physical mix-state, and by modifying the particle size but it seems like that the net effect is due to increased interactions. In any case, it is clear that optimisation of interactions can be achieved by obtaining a homogeneous phase.

Comparison of structure and properties of conventional and “high crystallinity” isotactic polypropylenes and their blends with metallocene‐catalyzed linear low density polyethylene. II. Morphological studies

The morphology of high crystallinity polypropylene (h.cr.PP) and metallocene-catalyzed linear low density polyethylene blends has been investigated using optical microscopy, scanning electron microscopy, and wide-angle X-ray scattering. The data obtained were analyzed and compared with results from physical testing. It was concluded that the improved physical performance of pure h.cr.PP, as well as its blends, compared with conventional PP and its blends was due to the alteration (suppression) of spherulitic structure of the former caused by the presence of nucleating agents. These additives (nucleating agents) appear also to cause the formation of fine lamellae in h.cr.PP, which could be an additional factor contributing to the improvement of the properties. A co-continuous structure of the blends comprised from two phases is shown to be superior to a matrix-dispersed one for improving the balance of mechanical properties. Co-continuity can exist and contribute to the improvement of the properties in systems either with or without spherulites.

Mechanical and thermal properties of melt processed PLA/organoclay nanocomposites

Polylactic acid (PLA) and organically modified layered silicates (organoclay) with concentrations of 2-10 wt% were prepared by melt intercalation technique. The effects of organoclay on the mechanical and thermal properties of PLA were studied. Tensile properties were evaluated using an Instron Universal Tester. Modulated differential scanning calorimetry (MDSC) and Thermogravimetric analyses (TGA) were performed to study the thermal behaviour of the prepared composites. The nanocomposites exhibited superior improvement of practical materials properties such as Youngs modulus and thermal stability, as compared to the neat PLA. The Youngs modulus drastically increased, whereas tensile strength and elongation at break decreased. The maximum degradation temperature of the hybrid increased linearly with an increasing amount of organoclay. However, MDSC has determined that the glass transition, cold crystallisation, and melting point temperatures were not significantly influenced by the presence of organoclay.

A Comparison of Assessment Methods for Engineering Students’ Understanding of Sustainability

Developing the ability of students to think critically and systemically about sustainability issues is assessed in a variety of ways in different disciplines and institutions but there are few reports in the literature about what methods are the most successful. This paper discusses a range of assessment methods and characterises them in terms of Bloom’s taxonomy of cognitive processes. Examinations are efficient, standardisable and objective but are not suitable for measuring sustainability learning. They promote surface learning and fail to measure higher order cognitive processes characteristic of sustainability competence. Project based learning (PjBL) is a common approach in engineering disciplines as it mirrors engineering work. PjBL assessment tasks such as reports and presentations can be marked using taxonomies such as the SOLO taxonomy which measure the higher order cognitive processes that are required for sustainability competence. However, markers need a high level of skill to mark reliability with rubrics based on the SOLO taxonomy. Graphical tools such as concept maps are also effective in measuring higher order cognitive processes.

What do Life Science employers look for in graduates

As part of an Australian Government Office for Learning and Teaching (OLT) grant to develop graduate employability through partnerships with industry and professional associations, RMIT University invited industry representatives from Life Science (microbiology focused) professions to a focus group to discuss their views on desirable graduate traits and attitudes. Subsequently current Life Science students at RMIT were also invited to focus groups. Using an expanded framework for graduate employability, their responses were coded and analysed and compared with responses from similar focus groups from other RMIT programs.