title: Low-Cost α+β PM Ti Alloys by Fe/Ni Addition to Pure Ti

authors: Bolzoni, Leandro

subjects: Elemental titanium

abstract: Ti and its alloys can deliver a very interesting combination of properties such as low density, high strength, corrosion resistance and biocompatibility and, therefore, are very flexible materials which can be adapted to various applications. Nonetheless, Ti and Ti alloys are only employed in critical applications (i.e. aeronautical and aerospace, nautical, medical, etc.) or in products for leisure. In both of these cases the higher fabrication costs of Ti in comparison to its competitors (i.e. steel and aluminium) is not the limiting factor as it is for many structural applications, especially for mass production (i.e. automotive sector). The use of creative techniques and the decrement of the starting price of Ti have been identified as the two main routes to follow to decrease the fabrication costs. In this study, the production of low-cost α+β Ti alloys has been assessed by combining the addition of cheap alloying elements (in particular a Fe/Ni powder) with the classical powder metallurgy route (pressing and sintering). Physical and mechanical properties as well as microstructural analysis of these low-cost alloys were measured and correlated to the processing parameters used to sinter them. It is found that the low-cost Ti alloys show similar behaviour to conventional α+β Ti alloys and, thus, have the potential to be used for non-critical applications.

text: Low-Cost α+β PM Ti Alloys by Fe/Ni Addition to Pure Ti Ti and its alloys can deliver a very interesting combination of properties such as low density, high strength, corrosion resistance and biocompatibility and, therefore, are very flexible materials which can be adapted to various applications. Nonetheless, Ti and Ti alloys are only employed in critical applications (i.e. aeronautical and aerospace, nautical, medical, etc.) or in products for leisure. In both of these cases the higher fabrication costs of Ti in comparison to its competitors (i.e. steel and aluminium) is not the limiting factor as it is for many structural applications, especially for mass production (i.e. automotive sector). The use of creative techniques and the decrement of the starting price of Ti have been identified as the two main routes to follow to decrease the fabrication costs. In this study, the production of low-cost α+β Ti alloys has been assessed by combining the addition of cheap alloying elements (in particular a Fe/Ni powder) with the classical powder metallurgy route (pressing and sintering). Physical and mechanical properties as well as microstructural analysis of these low-cost alloys were measured and correlated to the processing parameters used to sinter them. It is found that the low-cost Ti alloys show similar behaviour to conventional α+β Ti alloys and, thus, have the potential to be used for non-critical applications.

year: 2016

title: Infrastructure new findings for New Zealand

authors: Grimes, Arthur

subjects: economics

abstract: Infrastructure is a crucial input into economic production, and provision of infrastructure is a key avenue through which government may materially raise economic productivity. Recognising the importance of infrastructure investment, the Foundation for Research, Science and Technology granted Motu and its research partners a four-year research grant to examine the impacts that infrastructure investments have on New Zealand’s economic development. The programme has resulted in a range of empirical research studies that examine the impacts of specific and general infrastructure investments in this country. It has also resulted in contributions addressing theoretical and funding aspects related to infrastructure investment.

text: Infrastructure new findings for New Zealand Infrastructure is a crucial input into economic production, and provision of infrastructure is a key avenue through which government may materially raise economic productivity. Recognising the importance of infrastructure investment, the Foundation for Research, Science and Technology granted Motu and its research partners a four-year research grant to examine the impacts that infrastructure investments have on New Zealand’s economic development. The programme has resulted in a range of empirical research studies that examine the impacts of specific and general infrastructure investments in this country. It has also resulted in contributions addressing theoretical and funding aspects related to infrastructure investment.

year: 2010

title: Time to Diagnosis and Persistence: The Two Major Determinants of Effective Tuberculosis Control

authors: Ruthe, Alaine Tess

subjects: tuberculosis

abstract: The greatest challenge confronting effective tuberculosis (TB) eradication is the time to diagnosis, and duration of treatment of chronically infected individuals which represent a pool of infection. In an attempt to help limit the spread of TB in New Zealand, a fast SNP based diagnostic test was developed, to quickly identify the highly transmissible and virulent endemic Rangipo strain. The role of VapBC toxin-antitoxin systems in M. tuberculosis has been the subject of great interest recently, due to their expanded number in the genome and links with virulence and the regulation of cell growth in response to environmental stress. Their ability to regulate growth under adverse conditions for presumed survival advantages possibly leading to dormancy or persistence, make them ideal candidates for the development of new M. tuberculosis treatments. To establish differential expression of vapC, and therefore identify possible pathways and functions of the VapBC proteins, RT-qPCR was used to assess the expression levels of vapB and vapC in M. smegmatis under conditions of stress. No consistant changes in vapC mRNA levels were observed, resulting in the hypothesis that it is not the transcriptional differences which are important in the regulation of VapC, but post-transcriptional factors. In order to investigate the function(s) of M. tuberculosis VapBCs, these VapBC proteins were expressed and purified in M. smegmatis, and the VapC toxin tested for RNase activity. The purification, expression, RNase testing and bioinformatic analysis of M. tuberculosis VapCs suggested that VapCRv2530c, VapCRv0065 and VapCRv0617 may all target the same recognition sequence, UA*GG. Bioinformatic analysis revealed an abundance of this target sequence in horizontal gene transfer and TA genes, raising the possibility that VapC toxins could be functioning as selfish elements, or initiating transcriptional regulation cascades when a rapid change in the proteomic response and metabolic state of the cell is required. It is intriguing that the three M. tuberculosis VapC proteins tested thus far appear to target the same recognition sequence, possibly suggesting that all 47 VapCs are RNases and are targeting the same sequence. Alternatively; VapCs may belong to sub-groups targeting different sequences, allowing M. tuberculosis to exude both gross and fine metabolic control; or, they may share the same target, but are regulated by different activators triggered in response to different environmental stimuli.

text: Time to Diagnosis and Persistence: The Two Major Determinants of Effective Tuberculosis Control The greatest challenge confronting effective tuberculosis (TB) eradication is the time to diagnosis, and duration of treatment of chronically infected individuals which represent a pool of infection. In an attempt to help limit the spread of TB in New Zealand, a fast SNP based diagnostic test was developed, to quickly identify the highly transmissible and virulent endemic Rangipo strain. The role of VapBC toxin-antitoxin systems in M. tuberculosis has been the subject of great interest recently, due to their expanded number in the genome and links with virulence and the regulation of cell growth in response to environmental stress. Their ability to regulate growth under adverse conditions for presumed survival advantages possibly leading to dormancy or persistence, make them ideal candidates for the development of new M. tuberculosis treatments. To establish differential expression of vapC, and therefore identify possible pathways and functions of the VapBC proteins, RT-qPCR was used to assess the expression levels of vapB and vapC in M. smegmatis under conditions of stress. No consistant changes in vapC mRNA levels were observed, resulting in the hypothesis that it is not the transcriptional differences which are important in the regulation of VapC, but post-transcriptional factors. In order to investigate the function(s) of M. tuberculosis VapBCs, these VapBC proteins were expressed and purified in M. smegmatis, and the VapC toxin tested for RNase activity. The purification, expression, RNase testing and bioinformatic analysis of M. tuberculosis VapCs suggested that VapCRv2530c, VapCRv0065 and VapCRv0617 may all target the same recognition sequence, UA*GG. Bioinformatic analysis revealed an abundance of this target sequence in horizontal gene transfer and TA genes, raising the possibility that VapC toxins could be functioning as selfish elements, or initiating transcriptional regulation cascades when a rapid change in the proteomic response and metabolic state of the cell is required. It is intriguing that the three M. tuberculosis VapC proteins tested thus far appear to target the same recognition sequence, possibly suggesting that all 47 VapCs are RNases and are targeting the same sequence. Alternatively; VapCs may belong to sub-groups targeting different sequences, allowing M. tuberculosis to exude both gross and fine metabolic control; or, they may share the same target, but are regulated by different activators triggered in response to different environmental stimuli.

year: 2015