Mark C. Lay

Enhancing access to experiential learning in a science and technology degree programme

Abstract The research reported in this work concerned access to experiential learning offered in the form of work-based learning in a science and technology degree programme. The work-based learning comprises work placements within science and technology institutions relevant to the students discipline of academic study. Access to work placements was enhanced by improving student performance in pre-placement interviews and the study comprised the administration of an intervention, namely the use of trial interviews, to improve performance in pre-placement interviews. The study resulted in the development of a model for trial interviews based on models of competency identified in the literature and by examination of documentation from a variety of multi-national organisations. The data suggests that the students perceive trial interviews enhance performance during pre-placement interviews.

Scientists’ Habits of Mind as Evidenced by the Interaction Between their Science Training and Religious Beliefs

The science education literature suggests that the public and students often hold narrow stereotypical views of scientists and science. Here we argue that it is important that students and the public understand the basis on which scientists make scientific claims. The inquiry sought to develop an understanding of the scientific mind, explored through Gauld’s (2005) notion of ‘habits of mind’. The vehicle used to explore these ideas consisted of an inquiry into how scientists rationalise conflicts between scientific theories and religious beliefs which are not in agreement with consensually‐accepted scientific theories. Twenty scientists from different scientific disciplines and levels of seniority were interviewed using as a basis an instrument containing a series of religious‐based item statements that a panel of scientific and religious experts considered were in agreement with a variety of religious doctrines yet in disagreement with current scientific thinking, or for which there is at present no supporting evidence from a variety of scientific disciplines. These statements acted as an interview protocol and formed the basis for interactive discourse, which was audio‐taped, transcribed verbatim and participant‐validated. These data provide a window into scientific thinking as practiced by modern scientists, and helps develop a picture of these scientists’ ‘habits of mind’. The findings suggest that these scientists, unlike their stereotype, hold idiosyncratic views of what constitutes good scientific evidence and sound, credible testimony.

Effect of oxidative treatment on the secondary structure of decoloured bloodmeal

Bloodmeal can be decoloured using peracetic acid resulting in a material with a pale-yellow colour which only needs sodium dodecyl sulphate, water and triethylene glycol to extrude into a semi-transparent bioplastic. Fourier-transform infrared (FTIR) spectroscopy using Synchrotron light was used to investigate the effect of peracetic acid treatment at various concentrations on the spatial distribution of secondary structures within particles of bloodmeal. Oxidation caused aggregation of helical structures into sheets and acetic acid suppressed sheet formation. Decolouring with peracetic acid led to particles with a higher degree of disorder at the outer edges and higher proportions of ordered structures at the core, consistent with the expected diffusion controlled heterogeneous phase decolouring reaction. The degradation of stabilizing intra- and intermolecular interactions and the presence of acetate ions results in increased chain mobility and greater amorphous content in the material, as evidenced by reduction in Tg and greater enthalpy of relaxation with increasing PAA concentration.

DECOLORING HEMOGLOBIN AS A FEEDSTOCK FOR SECOND-GENERATION BIOPLASTICS

The color of red blood cell concentrate (RBCC) limits its application in human food, but there is potential to use it for second-generation bioplastics. Several methods have been developed to remove color from RBCC, but they are expensive or may produce difficult-to-remove toxic residues. Hydrogen peroxide treatment is a cheaper alternative. The effects of RBCC concentration, pH, and reaction temperature were the most important factors influencing the decolorizing process. They were investigated with the aim of developing a method that could be scaled to commercial level for producing a bioplastic feedstock. Initial trials showed pH was an important factor for decolorization and foaming. At pH 15 there was a 96% reduction in solution color and 8.4% solids were lost due to foaming. There was a 76% reduction in solution color at pH 2 and only 2.6% solids were lost due to foaming. The optimal reaction conditions were to centrifuge 9% w/w, pH 2 aqueous RBCC solution to remove aggregates. The solution was reacted at 30°C with 7.5 g of 30% (w/w) hydrogen peroxide. These conditions achieved a 93% reduction in solution color after 3 hr and the molecular weight of the decolored protein was not significantly reduced.

An ecoprofile of thermoplastic protein derived from blood meal Part 2: thermoplastic processing

PurposeThe purpose of this research was to develop a nonrenewable energy and greenhouse gas emissions ecoprofile of thermoplastic protein derived from blood meal (Novatein thermoplastic protein; NTP). This was intended for comparison with other bioplastics as well as identification of hot spots in its cradle-to-gate production. In Part 1 of this study, the effect of allocation on the blood meal used as a raw material was discussed. The objective of Part 2 was to assess the ecoprofile of the thermoplastic conversion process and to compare the cradle-to-gate portion of the polymers life cycle to other bioplastics.MethodsInventory was collected to aggregate nonrenewable primary energy use and greenhouse gas emissions. Data were collected from a variety of sources including published papers, reports to government agencies, engineering models and information from a single blood meal production facility. Several assumptions regarding the thermoplastic conversion process were evaluated by way of a sensitivity analysis.ResultsThe allocation procedure chosen for the impacts of farming and meat processing had the greatest effect on results. Excluding farming and meat processing, blood drying had the greatest contribution to nonrenewable energy use and GHGs, followed by the petrochemical plasticizer used. Other assumptions, such as scarcity of water or inclusion of pigments, although significant when considered for blood meal conversion to NTP alone, were found not to be significant when production of blood meal was included in the analysis. Qualitative differences were observed between NTP and other bioplastics. For example, the profiles of some other bio-based polymers were dominated by fermentation and polymer recovery processes. In the case of NTP, it is the production of the raw material used that is most significant, and thermoplastic modification has a relatively low contribution to GHGs and nonrenewable energy use.ConclusionsFor a truly attributional scenario, production of any ruminant animal products does have an associated GHG. Deriving this for blood meal on a mass-based allocation seems to indicate that NTP is less favorable than other cradle-to-gate bioplastic production systems from a global warming perspective.On the other hand, the motivation for developing the material in the first place was to make use of an existing waste product. If it is assumed that the magnitude of blood meal production is independent of fertilizer or plastics demand and, instead, reflects demand for major products such as meat, further development of NTP is justified.

Changes to amino acid composition of bloodmeal after chemical oxidation

Bovine-derived bloodmeal can be decoloured using peracetic acid, extruded and injection moulded into a yellow translucent bioplastic. This plastic has different properties to extruded and injection moulded bloodmeal, in that it does not require sodium sulfite or urea to be extrudable. The effect of oxidation on the physical and chemical characteristics of the proteins during bloodmeal decolouring with PAA was studied by assessing changes in the amino acid profile. Polymer interactions, hydrophilicity and the destruction of cysteine crosslinks were measured indirectly by assessing protein solubility, molecular weight distribution and by synchrotron FT-IR analysis. Increasing peracetic acid concentration resulted in an increased loss of iron due to destruction of the porphyrin groups, increased solubility due to destruction or conversion of aromatic amino acids into hydrophilic groups, destruction of lysine, reduced protein content due to increased salt content in the final product, and a larger amount of smaller protein peptides but with a similar average molecular weight to bloodmeal. Amino acid analysis showed an increase in cysteine content in the product, FT-IR of the sulfur groups revealed that these were heavily oxidised, such that some would be unable to participate in disulfide bonds thereby increasing protein solubility.

Blending Novatein® thermoplastic protein with PLA for carbon dioxide assisted batch foaming

The convenience of polymeric foams has led to their widespread utilisation in everyday life. However, disposal of synthetic petroleum-derived foams has had a detrimental effect on the environment which needs to be addressed. This study uses a clean and sustainable approach to investigate the foaming capability of a blend of two biodegradable polymers, polylactic acid (PLA) and Novatein® Thermoplastic Protein (NTP). PLA, derived from corn starch, can successfully be foamed using a batch technique developed by the Biopolymer Network Ltd. NTP is a patented formulation of bloodmeal and chemical additives which can be extruded and injection moulded similar to other thermoplastics. However, foaming NTP is a new area of study and its interaction with blowing agents in the batch process is entirely unknown. Subcritical and supercritical carbon dioxide have been examined individually in two uniquely designed pressure vessels to foam various compositions of NTP-PLA blends. Foamed material were characterised in term...

Extrusion foaming of protein-based thermoplastic and polyethylene blends

Currently the extrusion foamability of Novatein® Thermoplastic Protein (NTP) is being investigated at the University of Waikato in collaboration with the Biopolymer Network Ltd (NZ). NTP has been developed from bloodmeal (>86 wt% protein), a co-product of the meat industry, by adding denaturants and plasticisers (tri-ethylene glycol and water) allowing it to be extruded and injection moulded. NTP alone does not readily foam when sodium bicarbonate is used as a chemical blowing agent as its extensional viscosity is too high.The thermoplastic properties of NTP were modified by blending it with different weight fractions of linear low density polyethylene (LLDPE) and polyethylene grafted maleic anhydride (PE-g-MAH) compatibiliser. Extrusion foaming was conducted in two ways, firstly using the existing water content in the material as the blowing agent and secondly by adding sodium bicarbonate. When processed in a twin screw extruder (L/D 25 and 10 mm die) the material readily expanded due to the internal moi...

Effect of pore forming agents on geopolymer porosity and mechanical properties

Generation of industrial waste materials such as fly ash and slag in bulk provides an opportunity to convert these wastes into eco-friendly, value-added products. A geopolymer, a strong, porous and environmentally friendly material, was synthesized by mixing fly-ash with an alkaline activator, followed by addition of a pore forming agent (PFA) which created voids of varied pore sizes within the mixture. This polymer has potential applications as an adsorbent or membrane material; however, there is no established technology to regulate the pore size. Corn oil, waste palm oil and starch were investigated as potential organic additives to produce geopolymer materials with pore sizes suitable for water treatment membranes. Geopolymer without additives had a compressive strength of 30.93 MPa. Corn oil induced the highest porosity of up to 26.6 % with a compressive strength of 9.9 MPa, waste palm oil at 21.3 % and 9.0 MPa and starch at 17.9 % and 20.41 MPa. SEM analysis revealed that the voids and tunnels formation increased with increased PFA dosage.Generation of industrial waste materials such as fly ash and slag in bulk provides an opportunity to convert these wastes into eco-friendly, value-added products. A geopolymer, a strong, porous and environmentally friendly material, was synthesized by mixing fly-ash with an alkaline activator, followed by addition of a pore forming agent (PFA) which created voids of varied pore sizes within the mixture. This polymer has potential applications as an adsorbent or membrane material; however, there is no established technology to regulate the pore size. Corn oil, waste palm oil and starch were investigated as potential organic additives to produce geopolymer materials with pore sizes suitable for water treatment membranes. Geopolymer without additives had a compressive strength of 30.93 MPa. Corn oil induced the highest porosity of up to 26.6 % with a compressive strength of 9.9 MPa, waste palm oil at 21.3 % and 9.0 MPa and starch at 17.9 % and 20.41 MPa. SEM analysis revealed that the voids and tunnels forma...

Morphology and Mechanical Properties of Itaconic Anhydride Grafted Poly(lactic acid) and Thermoplastic Protein Blends

Abstract Blends between Novatein thermoplastic protein and polylactic acid (PLA) have been prepared by reactive extrusion using itaconic anhydride grafted PLA. At equal proportions of Novatein and PLA, the absence of a compatibilizer formed a dispersed phase morphology of Novatein in PLA and the incorporation of compatibilizer formed a co-continuous morphology. Incorporating PLA in Novatein can improve the tensile strength of Novatein by 42% and the impact strength by 36% at an equal proportion blend (50/50) in the presence of a compatibilizer. Thermal analysis revealed that 50/50 was the phase inversion point, above and below this composition the material behaved similarly. The effect of compatibilizer was evident in wide-angle X-ray scattering. In the absence of compatibilizer three phases were detected: crystalline Novatein, amorphous Novatein, and amorphous PLA phases. With compatibilizer, the blend was moving towards two phases: crystalline Novatein, and an amorphous blend of Novatein and PLA. Itaconic anhydride grafted PLA improved miscibility between Novatein and PLA, and its use can potentially lead to the production of Novatein/PLA foams.