title: Computational and empirical thermal modelling of a proposed SOFC stack housing design

authors: Fenton, Basil

abstract: Solid oxide fuel cells (SOFC) generate electricity cleanly, efficiently and quietly. There has been much effort in commercialising planar and large tubular SOFCs in the past two decades. Some research has involved modelling the mass, thermal and electrical energy flows in SOFC stack designs. Due to increased thermo-mechanical strength, a minitubular configuration offers quicker start up than planar designs, higher power densities than large tubular designs, and the potential for easier sealing. 
A stack housing design that bundled the small tubular fuel cells inside a three-way heat exchanger was proposed. Effluent fuel from the fuel cells was combusted to form an integrated burner. The air required is supplied by natural convection generated from the exhaust and hot gasses flowing up a flue (chimney). Experimental trials were done with a fabricated test rig (verification cell) to assess the stack housing design when operated with hydrogen-air. Temperature profiles data were collected to investigate the effect of varying fuel flow rate, chimney dimensions, and insulation. 
Code was written for the finite element program ANSYS® to model the verification cell. This included a simple model for the flame in the verification cell. Robustness of the model was investigated by varying software settings, and comparing predicted temperature profiles with measured temperature profiles for varying fuel flow rates, chimney dimensions, and insulation. 
The verification cell operated successfully on hydrogen-air but the temperature was not high or uniform enough to support a fuel cell stack. Using insulation increased temperatures and produced a more uniform temperature distribution. Increasing flue length increased temperatures marginally but increasing flue width decreased temperatures by 10%. 
A simple model for the hydrogen flame was used as the heat source in the verification cell to predict temperature profiles for a given set of flow rates and operating conditions. Temperature profiles could be correlated with flow rate within 10% of actual data for the air and exhaust manifolds, but accuracy was not translated for other fuel flow rates. The benefits and drawbacks of the ANSYS® program for modelling the SOFC stack are discussed and recommendations on further research given.

text: Computational and empirical thermal modelling of a proposed SOFC stack housing design Solid oxide fuel cells (SOFC) generate electricity cleanly, efficiently and quietly. There has been much effort in commercialising planar and large tubular SOFCs in the past two decades. Some research has involved modelling the mass, thermal and electrical energy flows in SOFC stack designs. Due to increased thermo-mechanical strength, a minitubular configuration offers quicker start up than planar designs, higher power densities than large tubular designs, and the potential for easier sealing. 
A stack housing design that bundled the small tubular fuel cells inside a three-way heat exchanger was proposed. Effluent fuel from the fuel cells was combusted to form an integrated burner. The air required is supplied by natural convection generated from the exhaust and hot gasses flowing up a flue (chimney). Experimental trials were done with a fabricated test rig (verification cell) to assess the stack housing design when operated with hydrogen-air. Temperature profiles data were collected to investigate the effect of varying fuel flow rate, chimney dimensions, and insulation. 
Code was written for the finite element program ANSYS® to model the verification cell. This included a simple model for the flame in the verification cell. Robustness of the model was investigated by varying software settings, and comparing predicted temperature profiles with measured temperature profiles for varying fuel flow rates, chimney dimensions, and insulation. 
The verification cell operated successfully on hydrogen-air but the temperature was not high or uniform enough to support a fuel cell stack. Using insulation increased temperatures and produced a more uniform temperature distribution. Increasing flue length increased temperatures marginally but increasing flue width decreased temperatures by 10%. 
A simple model for the hydrogen flame was used as the heat source in the verification cell to predict temperature profiles for a given set of flow rates and operating conditions. Temperature profiles could be correlated with flow rate within 10% of actual data for the air and exhaust manifolds, but accuracy was not translated for other fuel flow rates. The benefits and drawbacks of the ANSYS® program for modelling the SOFC stack are discussed and recommendations on further research given.

year: 2004

title: Evaluating the total factor productivity growth of national parks in china with data enveloped analysis

authors: Ma, Xiao-Long

subjects: national parks in China

abstract: The aim of this paper is to evaluate the total factor productivity (TFP) growth of national parks in China. The method of Malmquist Productivity Index based on data enveloped analysis is used. The result shows that 58.33% of national parks in China improved their TFP, and their mean score reached 3.42 in 2001-2005. When the decompositions are considered, 90.28% of them decreased their efficiency and 98.59% of them increased their technology. Correlation analysis indicates that these national parks' TFP is more constrained by their efficiency change than technology change. The correlation coefficients of them with Malmquist Productivity Index (MPI) reach to 0.7834 and 0.9367, respectively. Overall, the authors hold the opinion that most national parks in China increased their TFP during this period, but hindered by their inputs scale for preservation function, the efficiency of them deteriorated but the technology increased, further influencing the TFP. Finally, some methods to improve the performance of national parks for the governments and managers are discussed.

text: Evaluating the total factor productivity growth of national parks in china with data enveloped analysis The aim of this paper is to evaluate the total factor productivity (TFP) growth of national parks in China. The method of Malmquist Productivity Index based on data enveloped analysis is used. The result shows that 58.33% of national parks in China improved their TFP, and their mean score reached 3.42 in 2001-2005. When the decompositions are considered, 90.28% of them decreased their efficiency and 98.59% of them increased their technology. Correlation analysis indicates that these national parks' TFP is more constrained by their efficiency change than technology change. The correlation coefficients of them with Malmquist Productivity Index (MPI) reach to 0.7834 and 0.9367, respectively. Overall, the authors hold the opinion that most national parks in China increased their TFP during this period, but hindered by their inputs scale for preservation function, the efficiency of them deteriorated but the technology increased, further influencing the TFP. Finally, some methods to improve the performance of national parks for the governments and managers are discussed.

year: 2009

title: Whānau Stories: Creating meaningful engagement and wellbeing for the indigenous culture of Aotearoa New Zealand

authors: Cruse, Diana Caroline Annavale

subjects: Engagement

abstract: This research sees my interests coalesce into a particular focus on how collaborative partnerships with parents/caregivers can provide whānau Māori with opportunities to strengthen wellbeing in their own lives. It is located in Aotearoa New Zealand and within the context of Te Whāriki (Ministry of Education, 1996), Aotearoa New Zealand’s early childhood curriculum.  The Ministry of Education has a target that 98% of all children in Aotearoa New Zealand under 5 will attend an early childhood education setting (Ministry of Education, 2016), with Māori children having lower participation rates than the national participation rate (Ministry of Education, 2013).  The premise for this thesis is that meaningful whānau engagement in early learning contexts within Aotearoa New Zealand can empower whānau Māori, and honour the promises made in Te Tiriti o Waitangi of partnership, participation, and protection.
Therefore, this thesis sets out to examine what constitutes meaningful engagement for whānau Māori in an early childhood setting in Aotearoa New Zealand, and how meaningful engagement can assist whānau to enjoy an increase of wellbeing.
To explore this issue, I conducted research within an early childhood setting in Aotearoa New Zealand, using methodologies of Kaupapa Māori Research and Narrative Inquiry.  I listened to the narratives of whānau Māori indicating how meaningful engagement was created for them, and investigated if links were generated between engagement and wellbeing for their whānau. These links were identified in the literature as significant levers for educational success.
This research discovered three stages of engagement for the whānau Māori who participated in this study: establishing engagement, developing engagement and solidifying engagement.  Once created, meaningful engagement can lead to flourishing, indicating that there is relationship between meaningful engagement and whānau wellbeing.

text: Whānau Stories: Creating meaningful engagement and wellbeing for the indigenous culture of Aotearoa New Zealand This research sees my interests coalesce into a particular focus on how collaborative partnerships with parents/caregivers can provide whānau Māori with opportunities to strengthen wellbeing in their own lives. It is located in Aotearoa New Zealand and within the context of Te Whāriki (Ministry of Education, 1996), Aotearoa New Zealand’s early childhood curriculum.  The Ministry of Education has a target that 98% of all children in Aotearoa New Zealand under 5 will attend an early childhood education setting (Ministry of Education, 2016), with Māori children having lower participation rates than the national participation rate (Ministry of Education, 2013).  The premise for this thesis is that meaningful whānau engagement in early learning contexts within Aotearoa New Zealand can empower whānau Māori, and honour the promises made in Te Tiriti o Waitangi of partnership, participation, and protection.
Therefore, this thesis sets out to examine what constitutes meaningful engagement for whānau Māori in an early childhood setting in Aotearoa New Zealand, and how meaningful engagement can assist whānau to enjoy an increase of wellbeing.
To explore this issue, I conducted research within an early childhood setting in Aotearoa New Zealand, using methodologies of Kaupapa Māori Research and Narrative Inquiry.  I listened to the narratives of whānau Māori indicating how meaningful engagement was created for them, and investigated if links were generated between engagement and wellbeing for their whānau. These links were identified in the literature as significant levers for educational success.
This research discovered three stages of engagement for the whānau Māori who participated in this study: establishing engagement, developing engagement and solidifying engagement.  Once created, meaningful engagement can lead to flourishing, indicating that there is relationship between meaningful engagement and whānau wellbeing.

year: 2017