title: Advances in Quaternary tephrostratigraphy and tephrochronology in New Zealand

authors: Lowe, David J.

abstract: This paper summarises recent studies on Quaternary tephra deposits in New Zealand, and refers to a range of tephrochronological applications including sequence stratigraphy, palaeoclimatic reconstruction, and archaeology. Topics touched upon include tephrostratigraphy, geochronology, geochemical correlation techniques, volcanology, and volcanic hazards and impacts. Some key tephra marker beds, ranging in age from 0.65 ha to 1.63 Ma, are identified. Recently-acquired tephra-bearing cores from both terrestrial and deep-sea environments, extending through or beyond the Quaternary, provide great potential for detailed, fine-resolution volcanological and palaeoenvironmental studies. The tephra-based research in New Zealand demonstrates the importance of tephra deposits as stratigraphic markers, dating tools, and recorders of volcanic eruption history. An extensive reference list is provided.

text: Advances in Quaternary tephrostratigraphy and tephrochronology in New Zealand This paper summarises recent studies on Quaternary tephra deposits in New Zealand, and refers to a range of tephrochronological applications including sequence stratigraphy, palaeoclimatic reconstruction, and archaeology. Topics touched upon include tephrostratigraphy, geochronology, geochemical correlation techniques, volcanology, and volcanic hazards and impacts. Some key tephra marker beds, ranging in age from 0.65 ha to 1.63 Ma, are identified. Recently-acquired tephra-bearing cores from both terrestrial and deep-sea environments, extending through or beyond the Quaternary, provide great potential for detailed, fine-resolution volcanological and palaeoenvironmental studies. The tephra-based research in New Zealand demonstrates the importance of tephra deposits as stratigraphic markers, dating tools, and recorders of volcanic eruption history. An extensive reference list is provided.

year: 1999

title: Comparison of blended elemental (BE) and mechanical alloyed (MA) powder compact forging into Ti-6Al-4V rocker arms

authors: Jia, Mingtu

subjects: Powder compact forging

abstract: Ti-6Al-4V rocker arms for internal combustion engines were produced by forging of compacts of blended powder consisting of elemental hydride-dehydride (HDH) titanium powder and Al60V40 (wt%) master alloy powder or mechanical alloyed (MA) powder synthesized by high energy mechanical milling of a mixture of HDH titanium and Al60V40 master alloy powders. The powder compacts were made by warm compaction, and their relative density was 90%. The mechanical properties and microstructures of as-forged parts made using blended powder were improved significantly with increasing holding time at forging temperature, and close to those of as-forged parts produced by powder compact forging of HDH Ti-6Al-4V pre-alloyed powder. However, the as-forged part produced by powder compact forging of MA powder was brittle, and fractured prematurely during tensile testing.

text: Comparison of blended elemental (BE) and mechanical alloyed (MA) powder compact forging into Ti-6Al-4V rocker arms Ti-6Al-4V rocker arms for internal combustion engines were produced by forging of compacts of blended powder consisting of elemental hydride-dehydride (HDH) titanium powder and Al60V40 (wt%) master alloy powder or mechanical alloyed (MA) powder synthesized by high energy mechanical milling of a mixture of HDH titanium and Al60V40 master alloy powders. The powder compacts were made by warm compaction, and their relative density was 90%. The mechanical properties and microstructures of as-forged parts made using blended powder were improved significantly with increasing holding time at forging temperature, and close to those of as-forged parts produced by powder compact forging of HDH Ti-6Al-4V pre-alloyed powder. However, the as-forged part produced by powder compact forging of MA powder was brittle, and fractured prematurely during tensile testing.

year: 2012

title: The Effects of Contaminated Rena Sediments on Juvenile Paua (Haliotis iris)

authors: McSweeney, Caleb S.

subjects: contamiant

abstract: The grounding of the MV Rena on Otaiti resulted in the release of heavy fuel oil and container debris contaminants into the surrounding environments including the rocky shores of the adjacent Mōtītī Island. This is the habitat where significant populations of benthic paua reside. Paua (Haliotis iris) are a staple and consistent food source for Mōtītī Island. Being an offshore island with no amenities, Mōtītī Island residents are reliant on the ocean as a pataka kai (food cupboard) and are therefore acutely aware of environmental influences to the harvest of kaimoana.
This thesis aimed to address concerns relating to the effects of contaminated boundary layer water emanating from contaminated ‘Rena’ sediment on juvenile paua. Research was focused in two areas: 1) the sublethal behavioural effects of contaminated Rena sediment to Paua and 2) the accumulation of trace metals in the edible tissue and viscera mass. The experiments were carried out with the use of a close circuit aquaria in a laboratory environment, followed by a field experiment.
In all experiments, paua in control treatments were healthy by comparison to paua exposed to treatments with Rena contaminated sediments and copper as judged by survivorship and behaviour. The most likely cause of of behavioural aberrations and mortality observed was deemed to be copper as demonstrated by Diffusive Gradient in thin film (DGT) and ambient water analyses in both experiments. Copper that is bioavailable can increase quickly in the edible tissue and viscera mass as was identified as the visceral mass of Rena and copper exposed paua had a higher mean concentration of this and other trace metals.
On Otaiti, the effects to paua from the Rena ship wreck and lost container contents, know to include a medly of metals and other contaminants, is not likely to be limited to copper alone. Results demosntrate the relevance of examining the effects of water borne contaminated plumes emanating from complex mixtures of contaminants. This is rarely done in ecotoxicological studies which tend to focus on individual contaminant compounds.

text: The Effects of Contaminated Rena Sediments on Juvenile Paua (Haliotis iris) The grounding of the MV Rena on Otaiti resulted in the release of heavy fuel oil and container debris contaminants into the surrounding environments including the rocky shores of the adjacent Mōtītī Island. This is the habitat where significant populations of benthic paua reside. Paua (Haliotis iris) are a staple and consistent food source for Mōtītī Island. Being an offshore island with no amenities, Mōtītī Island residents are reliant on the ocean as a pataka kai (food cupboard) and are therefore acutely aware of environmental influences to the harvest of kaimoana.
This thesis aimed to address concerns relating to the effects of contaminated boundary layer water emanating from contaminated ‘Rena’ sediment on juvenile paua. Research was focused in two areas: 1) the sublethal behavioural effects of contaminated Rena sediment to Paua and 2) the accumulation of trace metals in the edible tissue and viscera mass. The experiments were carried out with the use of a close circuit aquaria in a laboratory environment, followed by a field experiment.
In all experiments, paua in control treatments were healthy by comparison to paua exposed to treatments with Rena contaminated sediments and copper as judged by survivorship and behaviour. The most likely cause of of behavioural aberrations and mortality observed was deemed to be copper as demonstrated by Diffusive Gradient in thin film (DGT) and ambient water analyses in both experiments. Copper that is bioavailable can increase quickly in the edible tissue and viscera mass as was identified as the visceral mass of Rena and copper exposed paua had a higher mean concentration of this and other trace metals.
On Otaiti, the effects to paua from the Rena ship wreck and lost container contents, know to include a medly of metals and other contaminants, is not likely to be limited to copper alone. Results demosntrate the relevance of examining the effects of water borne contaminated plumes emanating from complex mixtures of contaminants. This is rarely done in ecotoxicological studies which tend to focus on individual contaminant compounds.

year: 2015