title: The effect of inlet conditions on the air side hydraulic resistance and flow maldistribution in industrial air heaters

authors: Hoffmann-Vocke, Jonas

subjects: flow maldistribution

abstract: Experimental system hydraulic resistance measurements on a scale air heater unit have highlighted the excessive hydraulic resistance of typical industry configurations. Both poor header inlet conditions and large header expansion angles are shown to contribute to system hydraulic resistance magnitudes 20–100% higher than suitable benchmark cases. Typical centrifugal fan system efficiencies well under 80% multiply the system resistance effects resulting in larger fan power penalties. Velocity profile measurements taken upstream and downstream of the test heat exchanger under flow maldistribution conditions provide insight into the flow maldistribution spreading caused by the heat exchanger resistance. The anisotropic resistance of the plate fin-and-tube heat exchanger is shown to result in resistance induced flow dispersion being concentrated in the axis parallel to the plate fins.

text: The effect of inlet conditions on the air side hydraulic resistance and flow maldistribution in industrial air heaters Experimental system hydraulic resistance measurements on a scale air heater unit have highlighted the excessive hydraulic resistance of typical industry configurations. Both poor header inlet conditions and large header expansion angles are shown to contribute to system hydraulic resistance magnitudes 20–100% higher than suitable benchmark cases. Typical centrifugal fan system efficiencies well under 80% multiply the system resistance effects resulting in larger fan power penalties. Velocity profile measurements taken upstream and downstream of the test heat exchanger under flow maldistribution conditions provide insight into the flow maldistribution spreading caused by the heat exchanger resistance. The anisotropic resistance of the plate fin-and-tube heat exchanger is shown to result in resistance induced flow dispersion being concentrated in the axis parallel to the plate fins.

year: 2011

title: Nb-based heterogeneous nuclei for enhanced α-Mg nucleation in Mg(-Al) alloys

authors: Bolzoni, Leandro

subjects: Cast

abstract: The effect of the introduction of in-situ formed Nb-based compounds on Al-including Mg alloys has been investigated. It is found that grain refinement is consistently achieved. Nb-based intermetallic particles are responsible of the effective heterogeneous nucleation of Al-including Mg alloys. The refining mechanism is discussed on the base of crystallography.

text: Nb-based heterogeneous nuclei for enhanced α-Mg nucleation in Mg(-Al) alloys The effect of the introduction of in-situ formed Nb-based compounds on Al-including Mg alloys has been investigated. It is found that grain refinement is consistently achieved. Nb-based intermetallic particles are responsible of the effective heterogeneous nucleation of Al-including Mg alloys. The refining mechanism is discussed on the base of crystallography.

year: 2016-04-15

title: Reconnection with DNA: Policy and issues with direct-to-consumer DNA testing for indigenous Māori identity reclamation

authors: Turanga, Karen

abstract: The disconnection of tangata whenua (indigenous people born of the land) impacts all social determinants. A clear sense of identity and connection to the land and culture is an important solution to this problem. The purpose of this research is to share a personal and whānau (family group) story of using direct-to-consumer (DTC) autosomal DNA genetic testing (GT) to determine ancestry and show others a potential path forward to identity reclamation. To fulfil this purpose and explain the policy context, the research examines historical assimilation policies of closed cross-cultural adoption, and the possibilities DNA technology offers for whakapapa (genealogy, lineage descent, family history) reconnection. This includes addressing two key research questions: How does DTC-GT facilitate reconnection to Māori identity and whakapapa for cross-cultural adoptees? What are the short, medium and long-term risks and advantages of DTC autosomal DTC-GT testing for iwi Māori? A bricolage methodology frames this research and draws on kaupapa Māori (Māori approach, principles, and ideology), autoethnography, and interpretive phenomenology, which are used to analyse academic commentary and key policy decisions. An autoethnographic layered practice approach presents insights and key findings by combining personal narratives with various media types, academic research, policy documents and popular culture. The research highlights how the implicit processes of policy-led assimilation and colonisation still need to be challenged today. Existing literature has identified the importance of giving Māori pathways to reconnect with their identity. The personal story shared explains how DNA technology offers a way to do that, but the research completed for this thesis demonstrates this approach has serious risks and limitations that require consideration before utilising this technology.

text: Reconnection with DNA: Policy and issues with direct-to-consumer DNA testing for indigenous Māori identity reclamation The disconnection of tangata whenua (indigenous people born of the land) impacts all social determinants. A clear sense of identity and connection to the land and culture is an important solution to this problem. The purpose of this research is to share a personal and whānau (family group) story of using direct-to-consumer (DTC) autosomal DNA genetic testing (GT) to determine ancestry and show others a potential path forward to identity reclamation. To fulfil this purpose and explain the policy context, the research examines historical assimilation policies of closed cross-cultural adoption, and the possibilities DNA technology offers for whakapapa (genealogy, lineage descent, family history) reconnection. This includes addressing two key research questions: How does DTC-GT facilitate reconnection to Māori identity and whakapapa for cross-cultural adoptees? What are the short, medium and long-term risks and advantages of DTC autosomal DTC-GT testing for iwi Māori? A bricolage methodology frames this research and draws on kaupapa Māori (Māori approach, principles, and ideology), autoethnography, and interpretive phenomenology, which are used to analyse academic commentary and key policy decisions. An autoethnographic layered practice approach presents insights and key findings by combining personal narratives with various media types, academic research, policy documents and popular culture. The research highlights how the implicit processes of policy-led assimilation and colonisation still need to be challenged today. Existing literature has identified the importance of giving Māori pathways to reconnect with their identity. The personal story shared explains how DNA technology offers a way to do that, but the research completed for this thesis demonstrates this approach has serious risks and limitations that require consideration before utilising this technology.

year: 2025-08-08