title: Microstructural evolution during mechanical milling of Ti/Al powder mixture and production of intermetallic TiAl cathode target

authors: Gabbitas, Brian

subjects: titanium aluminides

abstract: Titanium aluminides are of great technological interest because of their attractive mechanical properties. Mechanical milling/alloying is a promising powder metallurgical technique, which can achieve ultrafine, uniform and manipulable microstructures. In this study, we employed a recently revisited discus mill to produce a composite Ti– (50–57) at.%Al powder feedstock, which is suitable for hot consolidation to produce bulk cathode targets for physical vapour deposition (PVD) coatings. The effects of milling time, quantity of process control agent (PCA) and discus-topowder weight ratio (DPR) on the microstructure evolution of the attendant Ti/Al composite powder were investigated in detail. It was found that to produce Ti/Al composite powders with a fine particle size and a uniform microstructure, the practicable processing parameters should be 2 or 3% isopropanol addition as PCA, 12 h of milling time and at least 13:1 DPR weight ratio. Cathode targets were produced by hot isostatic pressing (HIPing) the as-milled powders. The targets were then used to produce a PVD TiAlN coating which had an average microhardness of 2400 HV.

text: Microstructural evolution during mechanical milling of Ti/Al powder mixture and production of intermetallic TiAl cathode target Titanium aluminides are of great technological interest because of their attractive mechanical properties. Mechanical milling/alloying is a promising powder metallurgical technique, which can achieve ultrafine, uniform and manipulable microstructures. In this study, we employed a recently revisited discus mill to produce a composite Ti– (50–57) at.%Al powder feedstock, which is suitable for hot consolidation to produce bulk cathode targets for physical vapour deposition (PVD) coatings. The effects of milling time, quantity of process control agent (PCA) and discus-topowder weight ratio (DPR) on the microstructure evolution of the attendant Ti/Al composite powder were investigated in detail. It was found that to produce Ti/Al composite powders with a fine particle size and a uniform microstructure, the practicable processing parameters should be 2 or 3% isopropanol addition as PCA, 12 h of milling time and at least 13:1 DPR weight ratio. Cathode targets were produced by hot isostatic pressing (HIPing) the as-milled powders. The targets were then used to produce a PVD TiAlN coating which had an average microhardness of 2400 HV.

year: 2011

title: Submerged Thin Plate Weirs With Unequal Upstream and Downstream Beds

authors: Nalder, Guinevere Vivianne

subjects: thin plate weirs

abstract: This thesis describes a short study to examine the behaviour of submerged flow over a thin plate weir with differing upstream and downstream bed levels i.e. an unequal bed weir as opposed to an equal bed weir where the upstream and downstream beds are at the same level.

As submerged weir flow is a function of downstream conditions, it was thought that a lower downstream bed would make submerged flow over the weir easier, This is turn suggested that;
 	The shape of the upstream head (Hu) vs downstream head (Hd) graph would change, being initially more steep in the unequal bed case.
 	The Froude Number of the approaching flow would be lower for the unequal bed weir than for an equal bed weir at the same submergence.
 	Using one of the existing submerged flow formula would lead to an erroneous calculated value.

A series of measurements was done on two model weirs of different sizes subject to successive levels of submergence. Analysis of the readings of upstream and downstream heads indicated that the difference in bed levels was significant and the three effects above were noted.

The work also suggested a new form of equation to calculate flow over a submerged weir. This was looked at briefly.

text: Submerged Thin Plate Weirs With Unequal Upstream and Downstream Beds This thesis describes a short study to examine the behaviour of submerged flow over a thin plate weir with differing upstream and downstream bed levels i.e. an unequal bed weir as opposed to an equal bed weir where the upstream and downstream beds are at the same level.

As submerged weir flow is a function of downstream conditions, it was thought that a lower downstream bed would make submerged flow over the weir easier, This is turn suggested that;
 	The shape of the upstream head (Hu) vs downstream head (Hd) graph would change, being initially more steep in the unequal bed case.
 	The Froude Number of the approaching flow would be lower for the unequal bed weir than for an equal bed weir at the same submergence.
 	Using one of the existing submerged flow formula would lead to an erroneous calculated value.

A series of measurements was done on two model weirs of different sizes subject to successive levels of submergence. Analysis of the readings of upstream and downstream heads indicated that the difference in bed levels was significant and the three effects above were noted.

The work also suggested a new form of equation to calculate flow over a submerged weir. This was looked at briefly.

year: 2006

title: The Impact of Colonisation on the Maori community: An exploration of the attitudes and perspectives held by Maori in relation to the active reclamation of Maori sovereignty/tino rangatiratanga.

authors: Baty, Tina Amy

subjects: Maori

abstract: Whāia te iti kahurangi ki te tūohu koe me he maunga teitei
Seek the treasure you value most dearly: If you bow your head, let it be to a lofty mountain
The purpose of my research was twofold. I first sort to explore the attitudes and perspectives held by Māori in relation to the active reclamation of Māori sovereignty, tino rangatiratanga. I further wanted to know how Māori sovereignty, tino rangatiratanga could lead to the improvement of Māori health.
My research collected information pertinent to these two inquiries from current literature and from interviews I conducted with five Māori individuals from different iwi, hapu groups. All whom were actively engaged with the Māori community in some form. My research data found that colonisalism has and continues to negatively impact the Māori community. This negative impact manifests in a variety of behaviours that effect Māori health and leads to poor outcomes for Māori. Māori sovereignty, tino rangatiratanga was thought of as the solution to overcome and neutralise the negative effects of colonialism experienced by Māori. Māori sovereignty, tino rangatiratanga was found to be related with Māori idenity and instrumental in all things pertinent to the Māori communities.
My research found that Māori sovereignty, tino rangatiratanga can be identified as existing on a philosophical level, governance-structural level, and on a day-to-day basis. This research found that the reclamation of Māori sovereignty, tino rangatiratanga is a process that is currently in motion. Finally, the exercising of Māori sovereignty, tino rangatiratanga in relation to Māori health provides a well-established argument that it can produce positive health benefits to the Māori community, because it is responsive to Māori and better meets the needs of our Māori community simply because it is a Māori way of being, doing and knowing.

text: The Impact of Colonisation on the Maori community: An exploration of the attitudes and perspectives held by Maori in relation to the active reclamation of Maori sovereignty/tino rangatiratanga. Whāia te iti kahurangi ki te tūohu koe me he maunga teitei
Seek the treasure you value most dearly: If you bow your head, let it be to a lofty mountain
The purpose of my research was twofold. I first sort to explore the attitudes and perspectives held by Māori in relation to the active reclamation of Māori sovereignty, tino rangatiratanga. I further wanted to know how Māori sovereignty, tino rangatiratanga could lead to the improvement of Māori health.
My research collected information pertinent to these two inquiries from current literature and from interviews I conducted with five Māori individuals from different iwi, hapu groups. All whom were actively engaged with the Māori community in some form. My research data found that colonisalism has and continues to negatively impact the Māori community. This negative impact manifests in a variety of behaviours that effect Māori health and leads to poor outcomes for Māori. Māori sovereignty, tino rangatiratanga was thought of as the solution to overcome and neutralise the negative effects of colonialism experienced by Māori. Māori sovereignty, tino rangatiratanga was found to be related with Māori idenity and instrumental in all things pertinent to the Māori communities.
My research found that Māori sovereignty, tino rangatiratanga can be identified as existing on a philosophical level, governance-structural level, and on a day-to-day basis. This research found that the reclamation of Māori sovereignty, tino rangatiratanga is a process that is currently in motion. Finally, the exercising of Māori sovereignty, tino rangatiratanga in relation to Māori health provides a well-established argument that it can produce positive health benefits to the Māori community, because it is responsive to Māori and better meets the needs of our Māori community simply because it is a Māori way of being, doing and knowing.

year: 2018