title: Identification of the floral source of New Zealand honeys

authors: Petchell, Laura Eleanor

subjects: Honey

abstract: Depending on the nectar source, honey is either unifloral (derived mostly from one plant type), or polyfloral (derived from multiple plant types). Unifloral honey has characteristic sensory properties, and is therefore of greater commercial value. Currently, identification of floral source involves pollen counting, a specialised and labour intensive process. The current research was aimed at developing an alternative, rapid, chemistry-based method of floral identification. The aroma of honey depends on volatile compounds present; these may be derived from the plant from which nectar was taken. Therefore by identifying volatiles in honey it could be possible to identify floral source. Solid-phase microextraction (SPME) is a technique that is useful for the headspace analysis of volatile compounds; when coupled with GC-MS it provides a powerful tool for fingerprinting volatiles in honey. GC-MS chromatograms of ten New Zealand unifloral honey types were obtained after headspace SPME extraction. Statistical analysis of the GC-MS chromatographic data was used to discriminate between floral types. Probability plots were used to identify compounds indicative of floral source; this method discriminated between honey types with 90% success. Hierarchical cluster analysis and principal component analysis were used to study the structure of the data. Learning algorithms in Weka (machine-learning software) were used to build models of data to classify honey types. The logistic model tree algorithm classified 89.8% of samples correctly. Such a model has the potential to be used to classify future honey samples, once further samples have been tested to validate the model.

text: Identification of the floral source of New Zealand honeys Depending on the nectar source, honey is either unifloral (derived mostly from one plant type), or polyfloral (derived from multiple plant types). Unifloral honey has characteristic sensory properties, and is therefore of greater commercial value. Currently, identification of floral source involves pollen counting, a specialised and labour intensive process. The current research was aimed at developing an alternative, rapid, chemistry-based method of floral identification. The aroma of honey depends on volatile compounds present; these may be derived from the plant from which nectar was taken. Therefore by identifying volatiles in honey it could be possible to identify floral source. Solid-phase microextraction (SPME) is a technique that is useful for the headspace analysis of volatile compounds; when coupled with GC-MS it provides a powerful tool for fingerprinting volatiles in honey. GC-MS chromatograms of ten New Zealand unifloral honey types were obtained after headspace SPME extraction. Statistical analysis of the GC-MS chromatographic data was used to discriminate between floral types. Probability plots were used to identify compounds indicative of floral source; this method discriminated between honey types with 90% success. Hierarchical cluster analysis and principal component analysis were used to study the structure of the data. Learning algorithms in Weka (machine-learning software) were used to build models of data to classify honey types. The logistic model tree algorithm classified 89.8% of samples correctly. Such a model has the potential to be used to classify future honey samples, once further samples have been tested to validate the model.

year: 2009

title: Effect of processing condition and composition on the microhardness of Cu-(2.5-10)vol.%Al₂O₃ nanocomposite powder particles produced by high energy mechanical milling

authors: Mukhtar, Aamir

subjects: processing conditions

abstract: Nanostructured Cu-(2.5-10vol.%)Al₂O₃ nanocomposites were produced using high energy mechanical milling. For the as-milled Cu- Al₂O₃ composite powder particles having Al₂O₃  volume fractions of 2.5% and 5%, the increase in average microhardness is significant with the increase of milling time from 12 hours to 24 hours. With the increase of the content of Al₂O₃ nanoparticles the microhardness increases and in the range of 255HV-270HV. The milled nanocomposite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the powder particles as a function of annealing temperature. The average microhardness increased/decreased for the Cu- Al₂O₃ composites after annealing at 150°C due to the dislocation density, while increasing the annealing temperature to 300°C and 400°C the average microhardness almost remained mostly unchanged. Further increasing the annealing temperature to 500°C causes significant decrease in average microhardness due to reduction in dislocation density and coarsening of Cu grains of the Cu- Al₂O₃ composite powders produced after 24 hours of milling. This paper is to report and discuss the changes of the microhardness of the material, caused by the compositions and processing conditions, used to fabricate the Cu-(2.5-10)vol.% Al₂O₃ nanocomposite powders.

text: Effect of processing condition and composition on the microhardness of Cu-(2.5-10)vol.%Al₂O₃ nanocomposite powder particles produced by high energy mechanical milling Nanostructured Cu-(2.5-10vol.%)Al₂O₃ nanocomposites were produced using high energy mechanical milling. For the as-milled Cu- Al₂O₃ composite powder particles having Al₂O₃  volume fractions of 2.5% and 5%, the increase in average microhardness is significant with the increase of milling time from 12 hours to 24 hours. With the increase of the content of Al₂O₃ nanoparticles the microhardness increases and in the range of 255HV-270HV. The milled nanocomposite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the powder particles as a function of annealing temperature. The average microhardness increased/decreased for the Cu- Al₂O₃ composites after annealing at 150°C due to the dislocation density, while increasing the annealing temperature to 300°C and 400°C the average microhardness almost remained mostly unchanged. Further increasing the annealing temperature to 500°C causes significant decrease in average microhardness due to reduction in dislocation density and coarsening of Cu grains of the Cu- Al₂O₃ composite powders produced after 24 hours of milling. This paper is to report and discuss the changes of the microhardness of the material, caused by the compositions and processing conditions, used to fabricate the Cu-(2.5-10)vol.% Al₂O₃ nanocomposite powders.

year: 2010

title: Land/seascapes of exclusion: social order on the coastal margins

authors: Ryks, John

abstract: The hegemonic discourse of coastal planning and development has an impact on the social ordering of Aotearoa/New Zealand’s coastal communities in a number of ways. One way in which social order is controlled and maintained is through the (ab)use of boundaries. Boundaries constructed and maintained under the authority of government and/or funded by development dictate where people may or may not live. In many cases these boundaries are used as instruments of exclusion. Boundaries constructed by hegemonic groups exclude those who define the coast according to other criteria. The hegemonic deployment of boundaries and the domination of coastal people and place generally is explored through an analysis of discourse. This analysis is structured according to differences in social order, coded as places of Otherness (heterotopia), Euclidean coasts, and places in transition reflecting images of both the former and the latter.
Drawing on a number of coastal communities, including the Northland community of Otia (otherwise known as the Seaweed Pickers), Taylor’s Mistake, Whitianga and the wealth enclave of Pauanui, it is shown that the land/seascape of coastal Aotearoa/New Zealand is gradually being disciplined through the design of coasts that are accommodating of a particular patronage. These ‘exclusive’ coasts appear in stark contrast to those places where an alternative social ordering takes place. Here, in the absence of a Euclidean spatiality, uncertainty and liminality feature in the social construction of the coast. Residents of these places mark out and define the coast in a way that is quite different from the accepted norm, a fact that determines a particular ‘cartographic anxiety’ on the part of the dominant. This anxiety is instrumental in the construction of Otherness and the (re)production of exclusion.

text: Land/seascapes of exclusion: social order on the coastal margins The hegemonic discourse of coastal planning and development has an impact on the social ordering of Aotearoa/New Zealand’s coastal communities in a number of ways. One way in which social order is controlled and maintained is through the (ab)use of boundaries. Boundaries constructed and maintained under the authority of government and/or funded by development dictate where people may or may not live. In many cases these boundaries are used as instruments of exclusion. Boundaries constructed by hegemonic groups exclude those who define the coast according to other criteria. The hegemonic deployment of boundaries and the domination of coastal people and place generally is explored through an analysis of discourse. This analysis is structured according to differences in social order, coded as places of Otherness (heterotopia), Euclidean coasts, and places in transition reflecting images of both the former and the latter.
Drawing on a number of coastal communities, including the Northland community of Otia (otherwise known as the Seaweed Pickers), Taylor’s Mistake, Whitianga and the wealth enclave of Pauanui, it is shown that the land/seascape of coastal Aotearoa/New Zealand is gradually being disciplined through the design of coasts that are accommodating of a particular patronage. These ‘exclusive’ coasts appear in stark contrast to those places where an alternative social ordering takes place. Here, in the absence of a Euclidean spatiality, uncertainty and liminality feature in the social construction of the coast. Residents of these places mark out and define the coast in a way that is quite different from the accepted norm, a fact that determines a particular ‘cartographic anxiety’ on the part of the dominant. This anxiety is instrumental in the construction of Otherness and the (re)production of exclusion.

year: 2002