title: Fabrication and characterization of micro-tubular solid oxide fuel cells

authors: Du, Yanhai

abstract: Solid oxide fuel cells (SOFC) are an energy efficient, low pollution technology for generating power and have the potential to revolutionize energy generation. Tubular and planar concepts are the most common SOFC systems. The primary objective of this study was to develop a cost-effective process for fabricating micro-tubular SOFCs and to investigate how to improve fuel cell performance. 
Two technical approaches were investigated for increasing the cell performance and reducing SOFC costs: (a) reducing electrolyte resistance by minimizing the electrolyte thickness, which consequently increases oxygen flux to the anode; and (b) using new electrolyte materials thereby making it possible for the fuel cell to operate at lower temperatures. 
The new material primarily investigated for the SOFC was strontium- and magnesium-doped lanthanum gallate (LSGM), in which the single-phase perovskite LSGM region was determined. Yttria-stabilized zirconia (YSZ) and gadolinium doped ceria (CGO) electrolyte systems were also studied. 
Paste extrusion was identified as a suitable method for high-speed manufacture of the tubular support components of SOFCs. Procedures were developed to extrude dense, straight, round (OD: 4.0±0. l mm), thin walled (0.2±0.02 mm) tubular LSGM and YSZ electrolytes. The research systematically investigated developing a fabrication process, designing the extrusion die, the effects of formulation and process additives and how to handle, dry and sinter the extrudate. 
The three-point bending strength of extruded and sintered LSGM was determined to be 287 MPa, 195 MPa, 184 MPa and 147 MPa at room temperature, 600°C, 800°C and 1000°C respectively. Room temperature burst strengths of the tubular electrolytes made from YSZ, LSGM and CGO were 127 MPa, 40 MPa and 63 MPa respectively. The average thermal expansion coefficients between room temperature and 800°C were 10.18xl0-6 /°C, 11.0lxl0-6 /°C and 12.04x10-6/°C, for YSZ, LSGM, and CGO respectively. 
The maximum power density at 800°C for a 220-μm thick LSGM electrolyte was 460-482 mW/cm2, which is more than double the power density for YSZ cells (200-220 mW/cm2) at 850°C. Reducing LSGM thickness from 550 μm to 220 μm increased the maximum power densities by more than 30%. Repeatable cell power outputs per cell of 2.5 W at 800°C and 2.8 W at 850°C were obtained. Cell performance degradation was measured at 12% during the 500-hour test. 
A novel tubular stack design concept was developed to significantly increase stack volumetric power packing density by 84% for a three-cell module or 116% for a five-cell module, compared to a single-tube cell design. This design can also increase fuel efficiency. 
Recommendations for future work are given. It is suggested that (1) an anodesupported nanosize LSGM electrolyte system be used for the next generation of intermediate-temperature SOFCs; (2) the LSGM layer be applied by plasma spraying; and (3) nickel-free anodes for LSGM electrolyte systems are developed. 
This comprehensive study discusses the relationship between the materials, processing, manipulation of the microstructure, properties and tubular SOFC performance. The unique process developed for producing tubular support components has been scaled to commercial production and represents a significant scientific, engineering and commercial perspective contribution to fuel cell technology.

text: Fabrication and characterization of micro-tubular solid oxide fuel cells Solid oxide fuel cells (SOFC) are an energy efficient, low pollution technology for generating power and have the potential to revolutionize energy generation. Tubular and planar concepts are the most common SOFC systems. The primary objective of this study was to develop a cost-effective process for fabricating micro-tubular SOFCs and to investigate how to improve fuel cell performance. 
Two technical approaches were investigated for increasing the cell performance and reducing SOFC costs: (a) reducing electrolyte resistance by minimizing the electrolyte thickness, which consequently increases oxygen flux to the anode; and (b) using new electrolyte materials thereby making it possible for the fuel cell to operate at lower temperatures. 
The new material primarily investigated for the SOFC was strontium- and magnesium-doped lanthanum gallate (LSGM), in which the single-phase perovskite LSGM region was determined. Yttria-stabilized zirconia (YSZ) and gadolinium doped ceria (CGO) electrolyte systems were also studied. 
Paste extrusion was identified as a suitable method for high-speed manufacture of the tubular support components of SOFCs. Procedures were developed to extrude dense, straight, round (OD: 4.0±0. l mm), thin walled (0.2±0.02 mm) tubular LSGM and YSZ electrolytes. The research systematically investigated developing a fabrication process, designing the extrusion die, the effects of formulation and process additives and how to handle, dry and sinter the extrudate. 
The three-point bending strength of extruded and sintered LSGM was determined to be 287 MPa, 195 MPa, 184 MPa and 147 MPa at room temperature, 600°C, 800°C and 1000°C respectively. Room temperature burst strengths of the tubular electrolytes made from YSZ, LSGM and CGO were 127 MPa, 40 MPa and 63 MPa respectively. The average thermal expansion coefficients between room temperature and 800°C were 10.18xl0-6 /°C, 11.0lxl0-6 /°C and 12.04x10-6/°C, for YSZ, LSGM, and CGO respectively. 
The maximum power density at 800°C for a 220-μm thick LSGM electrolyte was 460-482 mW/cm2, which is more than double the power density for YSZ cells (200-220 mW/cm2) at 850°C. Reducing LSGM thickness from 550 μm to 220 μm increased the maximum power densities by more than 30%. Repeatable cell power outputs per cell of 2.5 W at 800°C and 2.8 W at 850°C were obtained. Cell performance degradation was measured at 12% during the 500-hour test. 
A novel tubular stack design concept was developed to significantly increase stack volumetric power packing density by 84% for a three-cell module or 116% for a five-cell module, compared to a single-tube cell design. This design can also increase fuel efficiency. 
Recommendations for future work are given. It is suggested that (1) an anodesupported nanosize LSGM electrolyte system be used for the next generation of intermediate-temperature SOFCs; (2) the LSGM layer be applied by plasma spraying; and (3) nickel-free anodes for LSGM electrolyte systems are developed. 
This comprehensive study discusses the relationship between the materials, processing, manipulation of the microstructure, properties and tubular SOFC performance. The unique process developed for producing tubular support components has been scaled to commercial production and represents a significant scientific, engineering and commercial perspective contribution to fuel cell technology.

year: 2004

title: Job vacancy monitoring in New Zealand

authors: Silverstone, Brian

subjects: job vacancies

abstract: The now widespread use of the internet as a source of information on job vacancies may have undermined the usefulness of newspaper advertisements - and possibly surveys - as the traditional sources of timely, cost-effective and accurate information on labour market openings. This paper outlines the New Zealand Department of Labour job vacancy series.  This is followed by selected international illustrations, measurement options, job vacancy reporting and an assessment of the Department of Labour’s experience with vacancy monitoring. The overall aims of this paper are to raise the awareness, in principle, of job vacancy data as a useful indicator of labour market conditions and the challenges, in practice, of creating appropriate series.

text: Job vacancy monitoring in New Zealand The now widespread use of the internet as a source of information on job vacancies may have undermined the usefulness of newspaper advertisements - and possibly surveys - as the traditional sources of timely, cost-effective and accurate information on labour market openings. This paper outlines the New Zealand Department of Labour job vacancy series.  This is followed by selected international illustrations, measurement options, job vacancy reporting and an assessment of the Department of Labour’s experience with vacancy monitoring. The overall aims of this paper are to raise the awareness, in principle, of job vacancy data as a useful indicator of labour market conditions and the challenges, in practice, of creating appropriate series.

year: 2009-01

title: The use of trastuzumab in New Zealand women with breast cancer

authors: Lawrenson, Ross

subjects: Breast Neoplasms

abstract: Aim

Trastuzumab was first funded in New Zealand for use in HER2+ve stage I–III breast cancer in 2007. This observational study aims to ascertain the patterns of use of trastuzumab in women with invasive HER2+ve breast cancer, and assess the effectiveness of adjuvant trastuzumab in women with stage I–III HER2+ve breast cancer.
Methods

The Waikato and Auckland Breast Cancer Registries have clinical details of 12 372 women diagnosed with invasive breast cancer between June 2000 and May 2013. The proportion of women with HER2+ve breast cancer treated with trastuzumab was examined by age, ethnicity, stage and year of diagnosis. Differences in outcomes including the development of metastases and death were assessed for women with stage I–III HER2+ve breast cancer treated with both chemotherapy and trastuzumab, compared to women treated with chemotherapy alone.
Results

Among the 1587 HER2+ve breast cancer patients, 888 (56.0%) women received trastuzumab. The probability of having trastuzumab decreased with higher age and comorbidity score and increased with year of diagnosis, tumor size and cancer stage. Māori and Pacific women were less likely to be treated with trastuzumab. After adjustment for potential confounding factors, the treatment with trastuzumab improved breast cancer-specific mortality (adjusted hazard ratio 0.57, 95% CI: 0.35–0.93).
Conclusion

Overall, this observational study has shown a substantial improvement in survival for women with HER2+ve stage I–III breast cancer, and much of this improvement can be attributed to the introduction of trastuzumab. Changes in chemotherapy also appear to have led to improved outcomes.

text: The use of trastuzumab in New Zealand women with breast cancer Aim

Trastuzumab was first funded in New Zealand for use in HER2+ve stage I–III breast cancer in 2007. This observational study aims to ascertain the patterns of use of trastuzumab in women with invasive HER2+ve breast cancer, and assess the effectiveness of adjuvant trastuzumab in women with stage I–III HER2+ve breast cancer.
Methods

The Waikato and Auckland Breast Cancer Registries have clinical details of 12 372 women diagnosed with invasive breast cancer between June 2000 and May 2013. The proportion of women with HER2+ve breast cancer treated with trastuzumab was examined by age, ethnicity, stage and year of diagnosis. Differences in outcomes including the development of metastases and death were assessed for women with stage I–III HER2+ve breast cancer treated with both chemotherapy and trastuzumab, compared to women treated with chemotherapy alone.
Results

Among the 1587 HER2+ve breast cancer patients, 888 (56.0%) women received trastuzumab. The probability of having trastuzumab decreased with higher age and comorbidity score and increased with year of diagnosis, tumor size and cancer stage. Māori and Pacific women were less likely to be treated with trastuzumab. After adjustment for potential confounding factors, the treatment with trastuzumab improved breast cancer-specific mortality (adjusted hazard ratio 0.57, 95% CI: 0.35–0.93).
Conclusion

Overall, this observational study has shown a substantial improvement in survival for women with HER2+ve stage I–III breast cancer, and much of this improvement can be attributed to the introduction of trastuzumab. Changes in chemotherapy also appear to have led to improved outcomes.

year: 2017