title: Optimization of thermo-mechanical densification of bamboo

authors: Kadivar, Marzieh

abstract: Due to its reliability, strength, and ease of access, bamboo has become an attractive material for engineering applications. However, heterogeneous properties and durability issues still hinder the widespread use of bamboo as a building material. Thermo-mechanical treatment is a method to decrease the heterogeneity of bamboo culms and enhance mechanical properties and durability, but it may negatively impact dimensional stability. The objective of this study was to achieve the minimum spring back, water absorption, and thickness swelling for densified bamboo. Accordingly, the behavior of bamboo samples subjected to different thermo-mechanical (TM) treatments using a two-step analysis was investigated. In the first step, the optimum TM treatment for achieving the highest critical densification degree (DD) without shear failure was determined. In the second step, the three key elements of dimensional stability were studied for this optimum case. According to the first step results, the maximum achievable DD in which no shear failure happens and the texture is not disturbed is about 43.6%, and it can be obtained at 200 °C with a compression rate of 2 mm/min. X-ray densitometry analysis confirmed that DD of around 50% achieved the highest value of density, 1.30 g.cm−3. The results of step 2 revealed that the lowest values of spring back, water absorption, and thickness swelling, 4.72%, 23.80%, and 17.70% respectively, for densified bamboo occur when the densification process is conducted at 200 °C and adopting a compression rate of 6.7 mm/min. In conclusion, by manipulating and optimizing process parameters, the dimensional stability and final quality of densified bamboo can be improved, opening new opportunities for this class of material.

text: Optimization of thermo-mechanical densification of bamboo Due to its reliability, strength, and ease of access, bamboo has become an attractive material for engineering applications. However, heterogeneous properties and durability issues still hinder the widespread use of bamboo as a building material. Thermo-mechanical treatment is a method to decrease the heterogeneity of bamboo culms and enhance mechanical properties and durability, but it may negatively impact dimensional stability. The objective of this study was to achieve the minimum spring back, water absorption, and thickness swelling for densified bamboo. Accordingly, the behavior of bamboo samples subjected to different thermo-mechanical (TM) treatments using a two-step analysis was investigated. In the first step, the optimum TM treatment for achieving the highest critical densification degree (DD) without shear failure was determined. In the second step, the three key elements of dimensional stability were studied for this optimum case. According to the first step results, the maximum achievable DD in which no shear failure happens and the texture is not disturbed is about 43.6%, and it can be obtained at 200 °C with a compression rate of 2 mm/min. X-ray densitometry analysis confirmed that DD of around 50% achieved the highest value of density, 1.30 g.cm−3. The results of step 2 revealed that the lowest values of spring back, water absorption, and thickness swelling, 4.72%, 23.80%, and 17.70% respectively, for densified bamboo occur when the densification process is conducted at 200 °C and adopting a compression rate of 6.7 mm/min. In conclusion, by manipulating and optimizing process parameters, the dimensional stability and final quality of densified bamboo can be improved, opening new opportunities for this class of material.

year: 2021

title: The distribution of fish in the urban gully system streams of Hamilton City

authors: Aldridge, Brenda Michelle Te Aroha

abstract: The distribution of fish in the urban gully system streams of Hamilton City was investigated using various methods of fishing. Fishing methods used in the city wide survey included trap netting using Gee minnow and fyke nets, electric fishing, and spotlighting at selected sites. Water quality and habitat parameters were assessed at each of the sites to add information to instream freshwater fish assemblages (i.e., preferred habitat). Culverts were assessed downstream of all sites because, native freshwater fish of New Zealand are largely migratory, having both freshwater and marine life histories. Freshwater fish migrate between habitats, therefore barriers to swimming fish passage may determine the presence of fish species at inland sites. Pest fish were less common than native fish in this survey, although they represent a greater proportion of the fish caught, because the small pest fish mosquitofish are prolific breeders and were present in very high numbers at a few sites. This study has shown that some urban streams can support diverse fish assemblages where water quality and habitat conditions permit. Threatened species were found to be present in streams previously thought of as supporting little stream life with low fish habitat or biodiversity value. The need for restoration and management of these streams is vital if the diversity and distribution of native fish is to be maintained.

text: The distribution of fish in the urban gully system streams of Hamilton City The distribution of fish in the urban gully system streams of Hamilton City was investigated using various methods of fishing. Fishing methods used in the city wide survey included trap netting using Gee minnow and fyke nets, electric fishing, and spotlighting at selected sites. Water quality and habitat parameters were assessed at each of the sites to add information to instream freshwater fish assemblages (i.e., preferred habitat). Culverts were assessed downstream of all sites because, native freshwater fish of New Zealand are largely migratory, having both freshwater and marine life histories. Freshwater fish migrate between habitats, therefore barriers to swimming fish passage may determine the presence of fish species at inland sites. Pest fish were less common than native fish in this survey, although they represent a greater proportion of the fish caught, because the small pest fish mosquitofish are prolific breeders and were present in very high numbers at a few sites. This study has shown that some urban streams can support diverse fish assemblages where water quality and habitat conditions permit. Threatened species were found to be present in streams previously thought of as supporting little stream life with low fish habitat or biodiversity value. The need for restoration and management of these streams is vital if the diversity and distribution of native fish is to be maintained.

year: 2006-11-27

title: On the Role of Literature and Translation in Language Maintenance

authors: Harlow, Ray

subjects: literature

abstract: The paper investigates the actual and potential role which is played by the promotion of traditional and innovative literature in efforts to maintain minority language under threat from a dominant language. The arguments advanced in the controversy surrounding the incorporation of translated material in a minority language’s corpus are discussed, and the view represented that the appropriateness or otherwise of translating material into a minority language depends on the (sometimes implicit) ideological goals of the maintenance movement. Fishman’s (1991, 2001) Graded Intergenerational Disruption Scale provides a framework for this discussion.

text: On the Role of Literature and Translation in Language Maintenance The paper investigates the actual and potential role which is played by the promotion of traditional and innovative literature in efforts to maintain minority language under threat from a dominant language. The arguments advanced in the controversy surrounding the incorporation of translated material in a minority language’s corpus are discussed, and the view represented that the appropriateness or otherwise of translating material into a minority language depends on the (sometimes implicit) ideological goals of the maintenance movement. Fishman’s (1991, 2001) Graded Intergenerational Disruption Scale provides a framework for this discussion.

year: 2002-02