title: Studying carbonisation with raman spectroscopy

authors: McDonald-Wharry, John

abstract: Raman spectroscopy can provide fast and non-destructive analysis of carbonaceous materials. As it is able to detect nanometre-sized structural features, Raman spectroscopy is widely used in the study of carbon nanotubes, fullerenes, graphenes, and many other carbon-rich materials. Raman analysis has previously shown potential for estimating the heat treatment temperatures (HTT) employed in the preparation of Japanese cedar charcoals which suggested future usefulness in quality control . In the current work, Raman spectroscopy was used to investigate the nanostructural development which had occurred within various chars prepared and carbonised at a range of heat treatment temperatures between ≈ 340°C and 1000°C. Chars were produced from sucrose sugar as standard precursor of high purity and two sources of biomass common in New Zealand (Radiata pine wood and Harakeke leaf fibres). In chars produced at lower HTTs, signals could be detected which were interpreted as representing hydrogen-rich amorphous carbon structures. In contrast, the Raman spectra of well-carbonised chars produced at higher HTTs featured signals consistent with graphene-like structures with coherent domains limited in size to below a few nanometres across. Measurement of such signals provides the ability to evaluate the extent of nanostructural development, identify char samples which are ‘undercooked’ when compared to other char samples, and estimate effective HTTs used in the production of a given char sample. More detailed Raman analysis of Radiata-derived chars was carried out, including analysis of chars produced from carbonising pyrolysis tars. Results of Raman analysis were correlated to H/C atom ratios obtained through elemental analysis for these chars produced from Radiata pine.

text: Studying carbonisation with raman spectroscopy Raman spectroscopy can provide fast and non-destructive analysis of carbonaceous materials. As it is able to detect nanometre-sized structural features, Raman spectroscopy is widely used in the study of carbon nanotubes, fullerenes, graphenes, and many other carbon-rich materials. Raman analysis has previously shown potential for estimating the heat treatment temperatures (HTT) employed in the preparation of Japanese cedar charcoals which suggested future usefulness in quality control . In the current work, Raman spectroscopy was used to investigate the nanostructural development which had occurred within various chars prepared and carbonised at a range of heat treatment temperatures between ≈ 340°C and 1000°C. Chars were produced from sucrose sugar as standard precursor of high purity and two sources of biomass common in New Zealand (Radiata pine wood and Harakeke leaf fibres). In chars produced at lower HTTs, signals could be detected which were interpreted as representing hydrogen-rich amorphous carbon structures. In contrast, the Raman spectra of well-carbonised chars produced at higher HTTs featured signals consistent with graphene-like structures with coherent domains limited in size to below a few nanometres across. Measurement of such signals provides the ability to evaluate the extent of nanostructural development, identify char samples which are ‘undercooked’ when compared to other char samples, and estimate effective HTTs used in the production of a given char sample. More detailed Raman analysis of Radiata-derived chars was carried out, including analysis of chars produced from carbonising pyrolysis tars. Results of Raman analysis were correlated to H/C atom ratios obtained through elemental analysis for these chars produced from Radiata pine.

year: 2013

title: Testing the human factor: Radiocarbon dating the first peoples of the South Pacific

authors: Petchey, Fiona

subjects: Oceania

abstract: Archaeologists have long debated the origins and mode of dispersal of the immediate predecessors of all Polynesians and many populations in Island Melanesia. Such debates are inextricably linked to a chronological framework provided, in part, by radiocarbon dates. Human remains have the greatest potential for providing answers to many questions pertinent to these debates. Unfortunately, bone is one of the most complicated materials to date reliably because of bone degradation, sample pretreatment and diet. This is of particular concern in the Pacific where humidity contributes to the rapid decay of bone protein, and a combination of marine, reef, C₄, C₃ and freshwater foods complicate the interpretation of ¹⁴C determinations. Independent advances in bone pretreatment, isotope multivariate modelling and radiocarbon calibration techniques provide us, for the first time, with the tools to obtain reliable calibrated ages for Pacific burials. Here we present research that combines these techniques, enabling us to re-evaluate the age of burials from key archaeological sites in the Pacific.

text: Testing the human factor: Radiocarbon dating the first peoples of the South Pacific Archaeologists have long debated the origins and mode of dispersal of the immediate predecessors of all Polynesians and many populations in Island Melanesia. Such debates are inextricably linked to a chronological framework provided, in part, by radiocarbon dates. Human remains have the greatest potential for providing answers to many questions pertinent to these debates. Unfortunately, bone is one of the most complicated materials to date reliably because of bone degradation, sample pretreatment and diet. This is of particular concern in the Pacific where humidity contributes to the rapid decay of bone protein, and a combination of marine, reef, C₄, C₃ and freshwater foods complicate the interpretation of ¹⁴C determinations. Independent advances in bone pretreatment, isotope multivariate modelling and radiocarbon calibration techniques provide us, for the first time, with the tools to obtain reliable calibrated ages for Pacific burials. Here we present research that combines these techniques, enabling us to re-evaluate the age of burials from key archaeological sites in the Pacific.

year: 2010

title: Health equity and wellbeing among older people's caregivers in New Zealand during COVID-19: Protocol for a qualitative study.

authors: Burholt, Vanessa

subjects: Aged

abstract: BACKGROUND: Knowledge of the challenges unpaid caregivers faced providing care to older people during the COVID-19 pandemic is limited. Challenges may be especially pronounced for those experiencing inequitable access to health and social care. This participatory action research study, located in New Zealand, has four main objectives, (i) to understand the challenges and rewards associated with caregiving to older care recipients during the COVID-19 pandemic restrictions; (ii) to map and collate resources developed (or mobilised) by organisations during the pandemic; (iii) to co-produce policy recommendations, identify useful caregiver resources and practices, prioritise unmet needs (challenges); and, (iv) to use project results in knowledge translation, in order to improve caregivers access to resources, and raise the profile and recognition of caregivers contribution to society. METHODS AND ANALYSIS: Māori, Pacific and rural-dwelling caregivers to 30 older care-recipients, and 30 representatives from organisations supporting caregivers in New Zealand will be interviewed. Combining data from the interviews and caregivers letters (from an archive of older people's pandemic experiences), framework analysis will be used to examine the interrelated systems of the human ecological model and the impact on caregiving experiences during the pandemic. Resources that service providers had created or used for caregivers and older people will be collated and categorised. Through co-production with caregivers and community partners we will produce three short films describing caregivers' pandemic experiences; identify a suite of resources for caregivers to use in future events requiring self-isolation, and in everyday life; and generate ideas to address unresolved issues.

text: Health equity and wellbeing among older people's caregivers in New Zealand during COVID-19: Protocol for a qualitative study. BACKGROUND: Knowledge of the challenges unpaid caregivers faced providing care to older people during the COVID-19 pandemic is limited. Challenges may be especially pronounced for those experiencing inequitable access to health and social care. This participatory action research study, located in New Zealand, has four main objectives, (i) to understand the challenges and rewards associated with caregiving to older care recipients during the COVID-19 pandemic restrictions; (ii) to map and collate resources developed (or mobilised) by organisations during the pandemic; (iii) to co-produce policy recommendations, identify useful caregiver resources and practices, prioritise unmet needs (challenges); and, (iv) to use project results in knowledge translation, in order to improve caregivers access to resources, and raise the profile and recognition of caregivers contribution to society. METHODS AND ANALYSIS: Māori, Pacific and rural-dwelling caregivers to 30 older care-recipients, and 30 representatives from organisations supporting caregivers in New Zealand will be interviewed. Combining data from the interviews and caregivers letters (from an archive of older people's pandemic experiences), framework analysis will be used to examine the interrelated systems of the human ecological model and the impact on caregiving experiences during the pandemic. Resources that service providers had created or used for caregivers and older people will be collated and categorised. Through co-production with caregivers and community partners we will produce three short films describing caregivers' pandemic experiences; identify a suite of resources for caregivers to use in future events requiring self-isolation, and in everyday life; and generate ideas to address unresolved issues.

year: 2022