title: Development of blood meal protein thermoplastic

authors: Verbeek, Casparus Johan R.

abstract: Polymers are blended with other polymers to  combine their properties or improve physical characteristics and blending turns to be the most reliable techniques compare to synthesis of chemically new polymers. In the research of sustainable materials from non-potential food sources, bloodmeal is one of the best candidates for bioplastic manufacture. It is one of the highest non-synthetic sources of nitrogen coming from meat processing and approximately 80000 tonnes of raw blood is collected annually in New Zealand. Natural polymers often present processing difficulties as well as maintaining product quality over extended periods because of their hydrophilic nature. Blending bloodmeal with other polymers may offer a solution to this problem.  However, most blends are immiscible, and the processing are challenging because of dissimilar nature of natural and synthetic polymer, thus  requiring compatibilization to achieve good blends performance. The process to solve incompatibility is the compatibilizer should migrate to the interface, reducing the interfacial tension, stabilizing the blend morphology and improving the adhesion between phases in solid state, hence improving the mechanical properties. True thermodynamic term of miscibility of polymer blends is a mixture containing two or more components that form one phase system but this determination of miscibility may be rather ambiguous. In practice, polymer blend compositions is said compatible if they exhibit two phases on a microscopic level but the interactions between polymer groups might be reasonable in a manner that provides useful properties of the multicoponent system. In many instances, it is desirable to have two phases present, as long as we can control the multicomponent systems which depend on their structure, polymer interactions and phase sizes. We have identified several strategies in order to improve miscibility;

1. Addition of a small quantity of a third component that is miscible with both phases 
2. Addition of a copolymer whose one part is miscible with one phase and another with another phase 
3. Compounding blends in the presence of chemical reactants that lead to modification of at least one macromolecular species (reactive compatibilization), resulting in generation of an in-situ desired quantity of compatibilizer. 
The propose of this paper is to explore the potential of blending bloodmeal with other thermoplastic by taking account the type of polymer, type of compatibilization and processing condition in order to improve processability and mechanical properties.

text: Development of blood meal protein thermoplastic Polymers are blended with other polymers to  combine their properties or improve physical characteristics and blending turns to be the most reliable techniques compare to synthesis of chemically new polymers. In the research of sustainable materials from non-potential food sources, bloodmeal is one of the best candidates for bioplastic manufacture. It is one of the highest non-synthetic sources of nitrogen coming from meat processing and approximately 80000 tonnes of raw blood is collected annually in New Zealand. Natural polymers often present processing difficulties as well as maintaining product quality over extended periods because of their hydrophilic nature. Blending bloodmeal with other polymers may offer a solution to this problem.  However, most blends are immiscible, and the processing are challenging because of dissimilar nature of natural and synthetic polymer, thus  requiring compatibilization to achieve good blends performance. The process to solve incompatibility is the compatibilizer should migrate to the interface, reducing the interfacial tension, stabilizing the blend morphology and improving the adhesion between phases in solid state, hence improving the mechanical properties. True thermodynamic term of miscibility of polymer blends is a mixture containing two or more components that form one phase system but this determination of miscibility may be rather ambiguous. In practice, polymer blend compositions is said compatible if they exhibit two phases on a microscopic level but the interactions between polymer groups might be reasonable in a manner that provides useful properties of the multicoponent system. In many instances, it is desirable to have two phases present, as long as we can control the multicomponent systems which depend on their structure, polymer interactions and phase sizes. We have identified several strategies in order to improve miscibility;

1. Addition of a small quantity of a third component that is miscible with both phases 
2. Addition of a copolymer whose one part is miscible with one phase and another with another phase 
3. Compounding blends in the presence of chemical reactants that lead to modification of at least one macromolecular species (reactive compatibilization), resulting in generation of an in-situ desired quantity of compatibilizer. 
The propose of this paper is to explore the potential of blending bloodmeal with other thermoplastic by taking account the type of polymer, type of compatibilization and processing condition in order to improve processability and mechanical properties.

year: 2011

title: Deformation behaviour and processing of a powder metallurgy metastable beta titanium alloy

authors: Zhao, Qinyang

subjects: Powder metallurgy

abstract: Metastable beta titanium alloys have drawn great attention and became important structural materials in the aeronautical industry thanks to their overall physical and mechanical performance including ultra-high specific strength, excellent strength-ductility balance, outstanding corrosion resistance, wide service temperature range and great hardenability. However, the lack of enough understanding of the nature of their hot workability and deformation behaviour and insufficient data for optimising the respective hot processing conditions makes it difficult for the titanium manufacturing industry to implement the precise processing of metastable beta titanium alloys with required quality control. Furthermore, the exorbitant manufacturing cost limits their further widespread applications.

Our research group has initiated to fabricate titanium alloys from blended elemental powder mixtures by using the thermomechanical powder consolidation (TPC) approach, and it is demonstrated that the TPC process is a feasible method to cost-effectively produce titanium alloys from powder. In this research, a commercial metastable β titanium alloy, Ti-5Al-5V-5Mo-3Cr (Ti-5553), was fabricated via the TPC process from a blended elemental powder mixture, and its microstructure variation, mechanical properties, deformation behaviours and mechanisms (at both room temperature and elevated temperatures), workability, and post-heat treatment effects were systematically investigated. For comparison, similar research was undertaken for the ingot metallurgy (IM) counterpart Ti-5553 alloy that was prepared by conventional vacuum-arc melting and casting.

The as-consolidated power metallurgy (PM) Ti-5553 alloy has much finer grain size, higher β phase transformation temperature and higher interstitial element (oxygen and nitrogen) content than those of the IM counterpart. The PM alloy exhibits lower load-bearing capacity and tensile ductility than those of the IM alloy during the in-situ tensile test, and the coalesced grain boundary α (GB-α) and widened αʺ/β microcracks contribute to early brittle failure. The IM alloy has better compatible-slip-deformation capability than the PM alloy, and the serious cracking at the V-shape notch and the microcracks near α/β interfaces together lead to the gradual fracture of the IM alloy specimen. The residual pores and microvoids existed in the PM alloy have little effects on the alloy’s slip deformation and fracture behaviour.

The PM Ti-5553 alloy’s flow stress is increased with decreasing the deformation temperature and increasing the strain rate, and vice versa. The alloy’s deformation activation energy is 371.65 kJ/mol in the (α+β) region and 226.94 kJ/mol in the β region, respectively. The optimal processing window for PM Ti-5553 alloy is determined as: processing temperature of 900 °C-1050 °C combined with deformation strain rates below 1 s⁻¹ with a high deformation degree to at least 70% height reduction. Furthermore, the potential “best” processing condition is recommended as the medium deformation temperature (about 950 °C) and moderate-low strain rate (about 0.01 s⁻¹). Because of flow localization and external cracking, unstable deformation happens when the deformation temperature is lower than 1025 °C and the strain rate is higher than 1 s⁻¹, and this region should be avoided for processing the PM Ti-5553 alloy.

The PM Ti-5553 alloy exhibits lower flow stress, slighter discontinuous yielding phenomenon and less adiabatic temperature rising than its IM counterpart for the same processing condition. Comparing to the IM Ti-5553 alloy, the PM Ti-5553 alloy has lower average activation energy, larger optimal processing windows, smaller flow instability region and higher cracking resistance. Dynamic α globularization and coarsening are the dominated mechanisms for the PM Ti-5553 alloy deformed at low temperature (700 °C to 800 °C) and low strain rate (less than 0.1 s⁻¹), while the IM Ti-5553 alloy is governed by dynamic α precipitation at these conditions. The complete dynamic recrystallization temperature for the PM alloy is about 100 °C lower than that of the IM counterpart, and dynamic recrystallization (DRX) mechanism is controlled by discontinuous dynamic recrystallization (DDRX) for the PM alloy but continuous dynamic recrystallization (CDRX) for the IM counterpart.

Based on the guidance of the hot processing map, the as-consolidated PM Ti-5553 alloy is safely thermomechanically-processed (single uniaxial open-die forging) at the temperatures of 950 °C and 1050 °C, strain rates about 0.5 s⁻¹ and 0.01 s⁻¹ to the deformation degree of 75%. The alloy forged at the condition of 950 °C/~0.01 s-1 (FR-1 alloy) shows the highest mechanical properties (UTS: 1450.9 MPa, elongation: 3.23% and MH: 492.4 HV), comparing to those processed at either higher temperature or higher strain rate.

Various heat treatments were carried out for the forged PM Ti-5553 alloy to tailor the alloy’s microstructure for achieving desired strength-ductility balance. Attributed to the harmonious concurrence of hierarchical α precipitation and heterogeneous grain structure, superior strength-ductility combinations are achieved for the FR-1 alloy after the heat treatment at 700 °C and 750 °C, with the UTS and elongation values of 1386.5 MPa/6.76% and 1252.3 MPa/8.64%, respectively. These strength-ductility combinations are comparable and/or even better than other IM metastable β titanium alloys.

text: Deformation behaviour and processing of a powder metallurgy metastable beta titanium alloy Metastable beta titanium alloys have drawn great attention and became important structural materials in the aeronautical industry thanks to their overall physical and mechanical performance including ultra-high specific strength, excellent strength-ductility balance, outstanding corrosion resistance, wide service temperature range and great hardenability. However, the lack of enough understanding of the nature of their hot workability and deformation behaviour and insufficient data for optimising the respective hot processing conditions makes it difficult for the titanium manufacturing industry to implement the precise processing of metastable beta titanium alloys with required quality control. Furthermore, the exorbitant manufacturing cost limits their further widespread applications.

Our research group has initiated to fabricate titanium alloys from blended elemental powder mixtures by using the thermomechanical powder consolidation (TPC) approach, and it is demonstrated that the TPC process is a feasible method to cost-effectively produce titanium alloys from powder. In this research, a commercial metastable β titanium alloy, Ti-5Al-5V-5Mo-3Cr (Ti-5553), was fabricated via the TPC process from a blended elemental powder mixture, and its microstructure variation, mechanical properties, deformation behaviours and mechanisms (at both room temperature and elevated temperatures), workability, and post-heat treatment effects were systematically investigated. For comparison, similar research was undertaken for the ingot metallurgy (IM) counterpart Ti-5553 alloy that was prepared by conventional vacuum-arc melting and casting.

The as-consolidated power metallurgy (PM) Ti-5553 alloy has much finer grain size, higher β phase transformation temperature and higher interstitial element (oxygen and nitrogen) content than those of the IM counterpart. The PM alloy exhibits lower load-bearing capacity and tensile ductility than those of the IM alloy during the in-situ tensile test, and the coalesced grain boundary α (GB-α) and widened αʺ/β microcracks contribute to early brittle failure. The IM alloy has better compatible-slip-deformation capability than the PM alloy, and the serious cracking at the V-shape notch and the microcracks near α/β interfaces together lead to the gradual fracture of the IM alloy specimen. The residual pores and microvoids existed in the PM alloy have little effects on the alloy’s slip deformation and fracture behaviour.

The PM Ti-5553 alloy’s flow stress is increased with decreasing the deformation temperature and increasing the strain rate, and vice versa. The alloy’s deformation activation energy is 371.65 kJ/mol in the (α+β) region and 226.94 kJ/mol in the β region, respectively. The optimal processing window for PM Ti-5553 alloy is determined as: processing temperature of 900 °C-1050 °C combined with deformation strain rates below 1 s⁻¹ with a high deformation degree to at least 70% height reduction. Furthermore, the potential “best” processing condition is recommended as the medium deformation temperature (about 950 °C) and moderate-low strain rate (about 0.01 s⁻¹). Because of flow localization and external cracking, unstable deformation happens when the deformation temperature is lower than 1025 °C and the strain rate is higher than 1 s⁻¹, and this region should be avoided for processing the PM Ti-5553 alloy.

The PM Ti-5553 alloy exhibits lower flow stress, slighter discontinuous yielding phenomenon and less adiabatic temperature rising than its IM counterpart for the same processing condition. Comparing to the IM Ti-5553 alloy, the PM Ti-5553 alloy has lower average activation energy, larger optimal processing windows, smaller flow instability region and higher cracking resistance. Dynamic α globularization and coarsening are the dominated mechanisms for the PM Ti-5553 alloy deformed at low temperature (700 °C to 800 °C) and low strain rate (less than 0.1 s⁻¹), while the IM Ti-5553 alloy is governed by dynamic α precipitation at these conditions. The complete dynamic recrystallization temperature for the PM alloy is about 100 °C lower than that of the IM counterpart, and dynamic recrystallization (DRX) mechanism is controlled by discontinuous dynamic recrystallization (DDRX) for the PM alloy but continuous dynamic recrystallization (CDRX) for the IM counterpart.

Based on the guidance of the hot processing map, the as-consolidated PM Ti-5553 alloy is safely thermomechanically-processed (single uniaxial open-die forging) at the temperatures of 950 °C and 1050 °C, strain rates about 0.5 s⁻¹ and 0.01 s⁻¹ to the deformation degree of 75%. The alloy forged at the condition of 950 °C/~0.01 s-1 (FR-1 alloy) shows the highest mechanical properties (UTS: 1450.9 MPa, elongation: 3.23% and MH: 492.4 HV), comparing to those processed at either higher temperature or higher strain rate.

Various heat treatments were carried out for the forged PM Ti-5553 alloy to tailor the alloy’s microstructure for achieving desired strength-ductility balance. Attributed to the harmonious concurrence of hierarchical α precipitation and heterogeneous grain structure, superior strength-ductility combinations are achieved for the FR-1 alloy after the heat treatment at 700 °C and 750 °C, with the UTS and elongation values of 1386.5 MPa/6.76% and 1252.3 MPa/8.64%, respectively. These strength-ductility combinations are comparable and/or even better than other IM metastable β titanium alloys.

year: 2020

title: Digital Taniwha: Growing Māori participation in the IT industry

authors: Williams, Warren

subjects: Māori research

abstract: This study explores the influencing factors on the participation levels of Māori (indigenous people of New Zealand) in the national IT industry. It particularly focusses on Māori IT professionals and why their participation in IT sector events and activities are not as visible as non-Māori. The researcher, who is also a Māori IT professional, has engaged with Māori in IT during his career, and forms the initial question of “where are they?”. The researcher proposes that more IT entrants and current IT professionals, who hold a Māori worldview grounded in cultural values that promote innovation and creativity, would benefit not only Māori but the IT industry and the nation. 

This thesis employs qualitative aligned research approaches - Kaupapa Māori and Wayfinding, to enable culturally appropriate methods during the data collection and analysis stages. It uses these approaches to support the inclusion of key cultural tenets such as Te Reo Māori (Māori language) and Māori values and practice. This research introduces the term “digital kaitiaki” to appropriately refer to Māori IT professionals. It collects data using appreciative inquiry and action research approaches and specific methods from semi-structured interviews held with digital kaitiaki; through focus groups with over 70 people; and records from action committees and working groups; to field observations of over 30 people. 

It examines the fieldwork data using thematic analysis and cross-checks the themes against influencing factors from the participant’s (including his own) personal and professional careers. The analysis identifies the following key themes: Māori identity and culture, feelings of personal and cultural responsibility, motivational forces, and role models. To respond to these, the study proposes a “Waka Kaitiaki Matihiko” model that connects with widely known Māori metaphors and symbols. It deploys these to inform and capture existing and potential future processes involving digital kaitiaki and to suggest how a culturally supported vehicle for Māori worldview engagement could encourage more Māori to enter IT and lend support for leadership roles for existing Māori IT workers.

To realise that potential, the study looks at leadership styles of the past to recognise what leadership is needed to increase contemporary Māori participation in the IT sector. It compares and contrasts leadership styles over time and constructs a new “digital taniwha” leadership style as fit for purpose for the challenge of growing Māori participation and for steering more Māori into leadership roles. Finally, by building on categories in the Blue Ocean Leadership grid and interweaving them with elements from existing Māori leadership literature, metaphors and symbols, and the findings from participants, it recommends a series of action-oriented interventions. These are designed to address the challenges identified in the key themes and feature governance and leadership programmes, as well as talent and career pathways, Te Reo Māori digital projects, tuakana/teina support and mentoring models, research into diversity representation (e.g., women and youth), and models designed to provide space to support the interventions proposed.

text: Digital Taniwha: Growing Māori participation in the IT industry This study explores the influencing factors on the participation levels of Māori (indigenous people of New Zealand) in the national IT industry. It particularly focusses on Māori IT professionals and why their participation in IT sector events and activities are not as visible as non-Māori. The researcher, who is also a Māori IT professional, has engaged with Māori in IT during his career, and forms the initial question of “where are they?”. The researcher proposes that more IT entrants and current IT professionals, who hold a Māori worldview grounded in cultural values that promote innovation and creativity, would benefit not only Māori but the IT industry and the nation. 

This thesis employs qualitative aligned research approaches - Kaupapa Māori and Wayfinding, to enable culturally appropriate methods during the data collection and analysis stages. It uses these approaches to support the inclusion of key cultural tenets such as Te Reo Māori (Māori language) and Māori values and practice. This research introduces the term “digital kaitiaki” to appropriately refer to Māori IT professionals. It collects data using appreciative inquiry and action research approaches and specific methods from semi-structured interviews held with digital kaitiaki; through focus groups with over 70 people; and records from action committees and working groups; to field observations of over 30 people. 

It examines the fieldwork data using thematic analysis and cross-checks the themes against influencing factors from the participant’s (including his own) personal and professional careers. The analysis identifies the following key themes: Māori identity and culture, feelings of personal and cultural responsibility, motivational forces, and role models. To respond to these, the study proposes a “Waka Kaitiaki Matihiko” model that connects with widely known Māori metaphors and symbols. It deploys these to inform and capture existing and potential future processes involving digital kaitiaki and to suggest how a culturally supported vehicle for Māori worldview engagement could encourage more Māori to enter IT and lend support for leadership roles for existing Māori IT workers.

To realise that potential, the study looks at leadership styles of the past to recognise what leadership is needed to increase contemporary Māori participation in the IT sector. It compares and contrasts leadership styles over time and constructs a new “digital taniwha” leadership style as fit for purpose for the challenge of growing Māori participation and for steering more Māori into leadership roles. Finally, by building on categories in the Blue Ocean Leadership grid and interweaving them with elements from existing Māori leadership literature, metaphors and symbols, and the findings from participants, it recommends a series of action-oriented interventions. These are designed to address the challenges identified in the key themes and feature governance and leadership programmes, as well as talent and career pathways, Te Reo Māori digital projects, tuakana/teina support and mentoring models, research into diversity representation (e.g., women and youth), and models designed to provide space to support the interventions proposed.

year: 2020