title: Production and characterization of titanium based alloys with potential for antifouling and biofouling

authors: Alshammari, Yousef Namlan

subjects: Titanium

abstract: Biofouling is the settlement and accumulation of microorganisms on the surface of a material submerged in sea water, and most of the time is an unwanted phenomenon and constitutes a financial burden. Titanium is a lightweight high strength metal characterised by good corrosion resistance, better than stainless steel, and would be the ideal material to be used in marine applications. However, biofouling would still happen in structures made out of titanium.
The aim of this study is to gain understanding of the biofouling process to be able to design Ti-based materials with the potential to prevent, or conversely enhance, biofouling, as both scenarios could have relevant industrial applications. In particular, it was planned to manufacture the Ti-based materials via powder metallurgy to take advantage of the intrinsic benefits of these techniques which include the freedom of designing new alloys, without the limits imposed by binary phase diagrams.
From literature, it was found that Cu and Mn could have respectively, the ability to reduce or promote biofouling. Therefore, various binary Ti-xCu and Ti-yMn compositions, where x = 0.5%, 2.5%, 5%, and y = 1%, 5%, 10%, were targeted and successfully manufactured via the conventional powder metallurgy route of cold uniaxial pressing plus vacuum sintering, obtaining fully homogeneous materials. 
It is well known that residual porosity is still present in sintered Ti-based materials, and for that the binary Ti-xCu and Ti-yMn alloys were also a thermomechanical process via forging. This hot deformation process should reduce the amount of residual porosity, but it can also be used to tailor the microstructure, and thus the mechanical behaviour, which is paramount for many industrial applications. Along this line, it was decided to investigate the effect of the forging temperature (i.e. of the starting microfeatures) and thus forging from the β and within the α+β region was considered.
From the characterisation performed, the Ti-5Cu and Ti-5Mn alloys were chosen as the most promising alloys for the investigation of the antifouling and biofouling capability of the binary Ti-xCu and Ti-yMn alloys developed

text: Production and characterization of titanium based alloys with potential for antifouling and biofouling Biofouling is the settlement and accumulation of microorganisms on the surface of a material submerged in sea water, and most of the time is an unwanted phenomenon and constitutes a financial burden. Titanium is a lightweight high strength metal characterised by good corrosion resistance, better than stainless steel, and would be the ideal material to be used in marine applications. However, biofouling would still happen in structures made out of titanium.
The aim of this study is to gain understanding of the biofouling process to be able to design Ti-based materials with the potential to prevent, or conversely enhance, biofouling, as both scenarios could have relevant industrial applications. In particular, it was planned to manufacture the Ti-based materials via powder metallurgy to take advantage of the intrinsic benefits of these techniques which include the freedom of designing new alloys, without the limits imposed by binary phase diagrams.
From literature, it was found that Cu and Mn could have respectively, the ability to reduce or promote biofouling. Therefore, various binary Ti-xCu and Ti-yMn compositions, where x = 0.5%, 2.5%, 5%, and y = 1%, 5%, 10%, were targeted and successfully manufactured via the conventional powder metallurgy route of cold uniaxial pressing plus vacuum sintering, obtaining fully homogeneous materials. 
It is well known that residual porosity is still present in sintered Ti-based materials, and for that the binary Ti-xCu and Ti-yMn alloys were also a thermomechanical process via forging. This hot deformation process should reduce the amount of residual porosity, but it can also be used to tailor the microstructure, and thus the mechanical behaviour, which is paramount for many industrial applications. Along this line, it was decided to investigate the effect of the forging temperature (i.e. of the starting microfeatures) and thus forging from the β and within the α+β region was considered.
From the characterisation performed, the Ti-5Cu and Ti-5Mn alloys were chosen as the most promising alloys for the investigation of the antifouling and biofouling capability of the binary Ti-xCu and Ti-yMn alloys developed

year: 2017

title: The description and modification of children's views of plant nutrition

authors: Barker, Miles

abstract: This study lies within the constructivist tradition in science education which holds that the learner's prior knowledge is a key factor in concept development. The topic was photosynthesis, which was known to be difficult for students although little was known of their prior understandings about plant activities. A three phase research programme was designed to arrive at a description of these pre-teach views (Part 1) and to use this knowledge in an action research programme which modified children's existing knowledge more effectively than current classroom practice (Part 2), 
Phase I comprised interviews with 28 pupils (aged 8 to 17 years). This lead to Phase II in which nearly 6000 pencil-and-paper survey responses were obtained from students from standard four (10- year-olds) to first year university (18+ years). The interviews and surveys showed that pre-teach children had a number of separate views about plant drinking, plant breathing, plant growth, how plants acquire energy, and plant feeding (these were collectively identified as views about 'plant nutrition'), but the children did not possess knowledge directly comparable with photosynthesis. As with earlier scientists' explanations, analogies and metaphors relating plants to animals were important in children's understandings. In contrast with what is known about children's prior knowledge generally, their views about plant nutrition were held with varying degrees of conviction and on some issues no views were evident. 
Phase III approached classroom action research by evaluating three existing strategies. Each of these (the guided discovery, element analysis, and trophic conflict strategies) was found to be deficient because children's prior knowledge was not considered and/or the scientists' view was not adequately addressed (i.e. food-making was considered at the expense of carbohydrate production or energy storage). A new strategy which explored the material aspects of photosynthesis (carbohydrate production)and which was based on the generative learning model was developed.
The new strategy resulted in a teaching package entitled "Where Does The Wood Come From?" which was trialled by an experienced and sympathetic teacher with a middle ability class of 26 fourth formers (14-year-olds). The class was observed throughout the four weeks of teaching, and individual students were also interviewed out of class at key times. After this unit, 71% of the students had acquired a view of photosynthesis as a carbohydrate-producing process. This contrasted with the usual guided discovery strategy, where a foodmaking view was the major outcome. Important observations were that the students perceived the unit as non-threatening, and that they underestimated the importance of their own ideas.
The study also documented some practical applications of the generative learning model (and constructivist theory generally) in the classroom. Investigations 1 surveys, a self-teach booklet, and a series of checkpoints were developed, and these features of the teaching package may have wider application. Also, it was suggested that the apparent similarities between children's views and those of earlier scientists may be used to facilitate classroom discussion and expose ideas. The findings of the action research resulted in suggested modifications to the generative learning model itself, especially its apparently sequential nature.

text: The description and modification of children's views of plant nutrition This study lies within the constructivist tradition in science education which holds that the learner's prior knowledge is a key factor in concept development. The topic was photosynthesis, which was known to be difficult for students although little was known of their prior understandings about plant activities. A three phase research programme was designed to arrive at a description of these pre-teach views (Part 1) and to use this knowledge in an action research programme which modified children's existing knowledge more effectively than current classroom practice (Part 2), 
Phase I comprised interviews with 28 pupils (aged 8 to 17 years). This lead to Phase II in which nearly 6000 pencil-and-paper survey responses were obtained from students from standard four (10- year-olds) to first year university (18+ years). The interviews and surveys showed that pre-teach children had a number of separate views about plant drinking, plant breathing, plant growth, how plants acquire energy, and plant feeding (these were collectively identified as views about 'plant nutrition'), but the children did not possess knowledge directly comparable with photosynthesis. As with earlier scientists' explanations, analogies and metaphors relating plants to animals were important in children's understandings. In contrast with what is known about children's prior knowledge generally, their views about plant nutrition were held with varying degrees of conviction and on some issues no views were evident. 
Phase III approached classroom action research by evaluating three existing strategies. Each of these (the guided discovery, element analysis, and trophic conflict strategies) was found to be deficient because children's prior knowledge was not considered and/or the scientists' view was not adequately addressed (i.e. food-making was considered at the expense of carbohydrate production or energy storage). A new strategy which explored the material aspects of photosynthesis (carbohydrate production)and which was based on the generative learning model was developed.
The new strategy resulted in a teaching package entitled "Where Does The Wood Come From?" which was trialled by an experienced and sympathetic teacher with a middle ability class of 26 fourth formers (14-year-olds). The class was observed throughout the four weeks of teaching, and individual students were also interviewed out of class at key times. After this unit, 71% of the students had acquired a view of photosynthesis as a carbohydrate-producing process. This contrasted with the usual guided discovery strategy, where a foodmaking view was the major outcome. Important observations were that the students perceived the unit as non-threatening, and that they underestimated the importance of their own ideas.
The study also documented some practical applications of the generative learning model (and constructivist theory generally) in the classroom. Investigations 1 surveys, a self-teach booklet, and a series of checkpoints were developed, and these features of the teaching package may have wider application. Also, it was suggested that the apparent similarities between children's views and those of earlier scientists may be used to facilitate classroom discussion and expose ideas. The findings of the action research resulted in suggested modifications to the generative learning model itself, especially its apparently sequential nature.

year: 1986

title: The presence of the past: Maori history in contemporary reflection

authors: Mahuika, Nepia

abstract: This is the opening line of a famous saying in my tribe. For our people - Ngāti Porou - these words have become embedded in our tribal identity as important directives that we are encouraged to aspire to. In the “days destined to you”, Ngata reminds us that each generation has its own mana (or authority), our own responsibilities and challenges, our own dreams and destinies to fulfil, and our own histories to tell about Ngāti Porou: who we are, our past, present, and future. If we consider this expectant, and I think hopeful, affirmation as a gift and responsibility, then taking real ownership of the “days destined to us” requires us to know what our forebears have entrusted us with. What are those historical gifts that we might use to “centre” and assert ourselves as Māori, as Ngāti Porou? We might look at this directly, i mua: the past before us because it is our history that is so crucial to us as we walk consciously, and with determination, into the future. Our past before us helps us to know where we are going, it helps us correc our course when we stray, keeps us mindful of the “kaupapa”: whatever that might be in our generation and corner of the Maori universe. We’ve heard already today from both Enoka and Arini how Māori, in our own ways, are engaging with our past, drawing on our korero tuku iho (our oral histories passed down across the generations), on our whakairo (our carving), to illuminate the many ways Māori do, and think about, the past.

text: The presence of the past: Maori history in contemporary reflection This is the opening line of a famous saying in my tribe. For our people - Ngāti Porou - these words have become embedded in our tribal identity as important directives that we are encouraged to aspire to. In the “days destined to you”, Ngata reminds us that each generation has its own mana (or authority), our own responsibilities and challenges, our own dreams and destinies to fulfil, and our own histories to tell about Ngāti Porou: who we are, our past, present, and future. If we consider this expectant, and I think hopeful, affirmation as a gift and responsibility, then taking real ownership of the “days destined to us” requires us to know what our forebears have entrusted us with. What are those historical gifts that we might use to “centre” and assert ourselves as Māori, as Ngāti Porou? We might look at this directly, i mua: the past before us because it is our history that is so crucial to us as we walk consciously, and with determination, into the future. Our past before us helps us to know where we are going, it helps us correc our course when we stray, keeps us mindful of the “kaupapa”: whatever that might be in our generation and corner of the Maori universe. We’ve heard already today from both Enoka and Arini how Māori, in our own ways, are engaging with our past, drawing on our korero tuku iho (our oral histories passed down across the generations), on our whakairo (our carving), to illuminate the many ways Māori do, and think about, the past.

year: 2016