title: Preparation and Properties of Natural, Demineralized, Pure, and Doped Carbons from Biomass; Model of the Chemical Structure of Carbonized Charcoal.

authors: Bourke, Jared

subjects: Flash Carbonization

abstract: Pioneering work performed by Rosalind Franklin over half a century ago provided the first structural models of two distinct carbon types: those that become graphitic during carbonization at high temperatures, and those that do not. Moreover it is known that certain properties of carbonaceous materials including combustion, surface area, electrical resistivity, and catalytic properties are influenced by mineral impurities.  The nature of this division in biocarbon structure and the known effects of minerals on carbon properties have led to this work; three principal topics were addressed; (1) the investigation of the solid state structure of biocarbons derived from various biomass feedstocks, (2) the removal of inorganic minerals from biomass, and (3) the investigation of biocarbon electronic structure subsequent to doping with select inorganic minerals.

Charcoals and carbonized charcoals (i.e. biocarbons) were prepared from a wide variety of biomass substrates, including pure sugars containing 5- and 6-membered rings with furanose and pyranose configurations, lignin, agricultural residues (corncob and nut shells) and a hard wood.  These biocarbons were subject to proximate and elemental analysis, gas sorption analysis, and analysis by ICP-MS, SEM, XRD, ESR, 13C CPMAS NMR, and MALDI-TOF MS.  All the carbonized charcoals contained oxygen heteroatoms, had high surface areas, and were excellent conductors of electricity.  Doping the biocarbon with boron or phosphorus resulted in a slight improvement in its electrical conductivity.  The XRD analysis indicated that the carbonized charcoals possess an aromaticity of about 71% that results from graphite crystallites with an average size of about 20  .  The NMR analysis confirmed the highly aromatic content of the carbonized charcoals.  The ESR signals indicated two major types of carbon-centered organic radicals.  A number of techniques employed highlighted differences between carbonized charcoals and synthetic graphite but none more so than MALDI-TOF spectrometry.  The biocarbons contained readily desorbed discrete ions with m/z values of 701, 685, 465, 453, 429, and 317.  All of the above findings were used to develop a model for the structure of carbonized charcoal that is consistent with the biocarbon's oxygen content, microporosity and surface area, electrical conductivity, radical content, and its MALDI-TOF spectra.

The removal of inorganic mineral constituents from various biomass feedstocks was achieved via simple washing/soaking techniques using two different aqueous media; deionized water and citric acid.  The most effective and consistent demineralization treatment for removing minerals from biomass involved a hot 0.1 molL-1 citric acid percolation treatment, ca.  67% of inorganic mineral matter was removed.  Mineral matter at the levels present in typical biomass derived charcoals and carbons had no significant influence upon the surface area or the electrical resistivity in carbonaceous materials after high heat treatment (950  C).

text: Preparation and Properties of Natural, Demineralized, Pure, and Doped Carbons from Biomass; Model of the Chemical Structure of Carbonized Charcoal. Pioneering work performed by Rosalind Franklin over half a century ago provided the first structural models of two distinct carbon types: those that become graphitic during carbonization at high temperatures, and those that do not. Moreover it is known that certain properties of carbonaceous materials including combustion, surface area, electrical resistivity, and catalytic properties are influenced by mineral impurities.  The nature of this division in biocarbon structure and the known effects of minerals on carbon properties have led to this work; three principal topics were addressed; (1) the investigation of the solid state structure of biocarbons derived from various biomass feedstocks, (2) the removal of inorganic minerals from biomass, and (3) the investigation of biocarbon electronic structure subsequent to doping with select inorganic minerals.

Charcoals and carbonized charcoals (i.e. biocarbons) were prepared from a wide variety of biomass substrates, including pure sugars containing 5- and 6-membered rings with furanose and pyranose configurations, lignin, agricultural residues (corncob and nut shells) and a hard wood.  These biocarbons were subject to proximate and elemental analysis, gas sorption analysis, and analysis by ICP-MS, SEM, XRD, ESR, 13C CPMAS NMR, and MALDI-TOF MS.  All the carbonized charcoals contained oxygen heteroatoms, had high surface areas, and were excellent conductors of electricity.  Doping the biocarbon with boron or phosphorus resulted in a slight improvement in its electrical conductivity.  The XRD analysis indicated that the carbonized charcoals possess an aromaticity of about 71% that results from graphite crystallites with an average size of about 20  .  The NMR analysis confirmed the highly aromatic content of the carbonized charcoals.  The ESR signals indicated two major types of carbon-centered organic radicals.  A number of techniques employed highlighted differences between carbonized charcoals and synthetic graphite but none more so than MALDI-TOF spectrometry.  The biocarbons contained readily desorbed discrete ions with m/z values of 701, 685, 465, 453, 429, and 317.  All of the above findings were used to develop a model for the structure of carbonized charcoal that is consistent with the biocarbon's oxygen content, microporosity and surface area, electrical conductivity, radical content, and its MALDI-TOF spectra.

The removal of inorganic mineral constituents from various biomass feedstocks was achieved via simple washing/soaking techniques using two different aqueous media; deionized water and citric acid.  The most effective and consistent demineralization treatment for removing minerals from biomass involved a hot 0.1 molL-1 citric acid percolation treatment, ca.  67% of inorganic mineral matter was removed.  Mineral matter at the levels present in typical biomass derived charcoals and carbons had no significant influence upon the surface area or the electrical resistivity in carbonaceous materials after high heat treatment (950  C).

year: 2007

title: Primary teachers, policy, and physical education

authors: Petrie, Kirsten Culhane

subjects: physical education

abstract: This article focuses on the challenges arising for primary school teachers who have responsibility for teaching physical education (PE) and who are working in particularly complex and contestable policy contexts. In New Zealand provision of physical education is identified as occurring amidst multiple, and not necessarily compatible, sets of expectations, associated with government priorities, initiatives focusing on children’s health, sport, and improved national achievement outcomes. This article examines the contemporary educational policy landscape, and the effect constantly shifting policy initiatives have on teachers’ work in physical education in primary schools. Key themes characterizing primary PE teaching/teachers’ situation currently centre on pressures to adhere to policies that have stricter accountability measures, the utilization of ‘external providers’, limited time for teacher learning and what appears to paralysis by policy. Discussion considers possible alternative approaches to the development of policy that would arguably better support teachers of physical education in primary schools.

text: Primary teachers, policy, and physical education This article focuses on the challenges arising for primary school teachers who have responsibility for teaching physical education (PE) and who are working in particularly complex and contestable policy contexts. In New Zealand provision of physical education is identified as occurring amidst multiple, and not necessarily compatible, sets of expectations, associated with government priorities, initiatives focusing on children’s health, sport, and improved national achievement outcomes. This article examines the contemporary educational policy landscape, and the effect constantly shifting policy initiatives have on teachers’ work in physical education in primary schools. Key themes characterizing primary PE teaching/teachers’ situation currently centre on pressures to adhere to policies that have stricter accountability measures, the utilization of ‘external providers’, limited time for teacher learning and what appears to paralysis by policy. Discussion considers possible alternative approaches to the development of policy that would arguably better support teachers of physical education in primary schools.

year: 2011

title: Older men gardening on the marae: Everyday practices for being Māori

authors: King, Pita

subjects: manaakitanga

abstract: Like indigenous peoples globally, Māori are over- represented among the homeless population due to processes of colonialism, disruptions and continued socio- economic marginalization. This article explores how, through gardening and other everyday practices, a group of older Māori men who are homeless find respite, reconnection, a sense of belonging, and remember Māori ways of being. We consider how the regular participation of these men also contributes to the reconciliation of the marae (communal complex used for everyday Māori life) space that has been reclaimed by Ngāti Whātua (local Auckland tribe) after a lengthy hiatus. Our analysis foregrounds the importance of core values of manaakitanga (care for others), whanaungatanga (relationships based on shared experience or kinship) and wairuatanga (spirituality) for responses to Māori homelessness.

text: Older men gardening on the marae: Everyday practices for being Māori Like indigenous peoples globally, Māori are over- represented among the homeless population due to processes of colonialism, disruptions and continued socio- economic marginalization. This article explores how, through gardening and other everyday practices, a group of older Māori men who are homeless find respite, reconnection, a sense of belonging, and remember Māori ways of being. We consider how the regular participation of these men also contributes to the reconciliation of the marae (communal complex used for everyday Māori life) space that has been reclaimed by Ngāti Whātua (local Auckland tribe) after a lengthy hiatus. Our analysis foregrounds the importance of core values of manaakitanga (care for others), whanaungatanga (relationships based on shared experience or kinship) and wairuatanga (spirituality) for responses to Māori homelessness.

year: 2015