Science and Engineering Papers

This collection houses research from the School of Science and from the School of Engineering at the University of Waikato.

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Now showing 1 - 5 of 3245
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    Utuhina Stream 2006-2020: In-stream alum dosing effects on fish and aquatic invertebrates
    (Report, Environmental Research Institute, School of Science, The University of Waikato, 2021-06) Ling, Nicholas
    This report presents the results of an on-going assessment of the fish and aquatic macroinvertebrate communities of the Utuhina Stream, Lake Rotorua, from 2006 to 2020, and an assessment of the bioavailability of aluminium in fish and kōura to satisfy Bay of Plenty Regional Council’s annual resource consent conditions 9.6, 9.8 and 9.7, respectively, for consent 65321 for the discharge of alum to the Utuhina Stream. Macroinvertebrates, fish and kōura (freshwater crayfish) were sampled from one control and two treatment reaches of the Utuhina Stream annually. Common bully (Gobiomorphus cotidianus) is the dominant species in the fish community of the Utuhina Stream. Kōura (Paranephrops planifrons) and juvenile trout were always present at all sites but variable in abundance. Differences in species abundance from year to year are most likely due to flood-related disturbances to stream bank morphology and in-stream vegetative cover or physical displacement of fish. No obvious effects of alum dosing on stream fish or macroinvertebrate communities were observed between the upstream control site and sites downstream of the alum discharge. Several other fish species were occasionally captured during sampling and the regular occurrence of juvenile koaro from 2016 to 2019 is possible evidence of this taonga species becoming established in the Utuhina. Analysis of stream macroinvertebrates also showed no consistent differences between the upstream control site and the sites downstream of the alum dosing. Overall, all sites were characterised as fair to good quality for a soft-bottomed stream. Some evidence of aluminium bioaccumulation was seen in some tissues of common bully (gills and liver) in some years, resulting from continuous alum dosing of the Utuhina Stream, but there was no evidence of bioaccumulation of aluminium in the tissues of kōura. Alum exposure in these species does not appear to affect their health or abundance in the stream. iii Overall, continuous alum discharge does not appear to negatively impact the ecology of the lower Utuhina and improvements in the ecological condition of the Utuhina Stream will be achieved by ongoing riparian restoration and mitigation of the impacts of flood flows.
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    Use of sisal microfibres and bleached eucalyptus pulp as reinforcement of MgO-SiO2 fibre cement
    (Conference Contribution, Zenodo, 2022-05-26) Gauss, Christian; Mármol, Gonzalo; Fioroni, Carlos; Savastano Jr., Holmer
    In this work, minimally processed sisal microfibres along with commercial eucalyptus pulp were used as reinforcement of composites based on magnesium oxide and silica cement (60/40 ratio by weight of MgO/SiO2) with high filler content. The fibre cement composites were submitted to a fast carbonation process, resulting in the formation of hydrated magnesium carbonate, which contributed to improved physical and mechanical properties. All composites presented a strain-hardening behaviour and high specific energy under flexural loading, in special the composites with 10% of fibres. We demonstrated that the sisal microfibres produced by a chemical/mechanical process can be used as an efficient reinforcing material in combination with commercial cellulose pulp for MgO-SiO2 composites.
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    Cultural and ethical implications of wearable technology uses
    (Report, University of Waikato, 2024-02) Miller, Jadon; Head, Mitchell Antony; Owen, Mahonri; Hoskens, Merel Cornelie Janna; König, Jemma Lynette; Bowen, Judy
    For Human-Computer Interaction (HCI) practitioners, interacting with people is a fundamental part of our work. When running any kind of user study, it is important to critically consider any ethical or cultural biases that we (or our data or methods) may have. While this is not a new consideration, the introduction of wearable technology has introduced new aspects to user studies which may not have been apparent previously. In this paper, we present a wearable technology-based user study as a case study to highlight cultural and ethical considerations. Cultural considerations centre on both the cultural considerations that should be made towards participants and considerations for their data. Ethical considerations centre on the immediate impact on participants’ privacy and agency and the longer-term impact on their mental and physical safety. Finally, we suggest that in situations where cultural and racial disparities affect participant expectations and technical results, it is essential to proactively explore these factors.
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    Rolling Our Eyes Towards God: An Intervention Arising from Mormon Missionary YouTube Activity and The Cultural (Mis)Appropriation of Haka
    (Journal Article, Taylor and Francis Group, 2023-02-05) Simon, Hemopereki
    This Kaupapa Māori Research writing inquiry explores the (mis)appropriation of haka and the social media video-sharing platform YouTube in that (mis)appropriation. The article examines the specific case of a group of Latter-day Saint missionaries in Wangarratta, Australia, who wrote and performed an English- language haka that the author finds violent and offensive. The article outlines Aileen Moreton-Robertson’s White Possessive doctrine in relation to the Church and white patriarchal salvation. Haka’s cultural background and appropriation are explained. Theoretical explanations of collective and cultural memory and YouTube as a social media platform and cultural archive follow. The author highlights YouTube grey literature sources on haka cultural (mis)appropriation. The 2006 case study “missionary haka” video is critiqued and analysed. Case study issues are discussed. The Church’s history of racial discrimination and violence and its religious aetiology of skin colour make this video ”misappropriated,” according to research. This performance uses haka to promote white and religious supremacy and the idea that you must be white and/or religious to be fully human. This message helps the LDS Church mission of possessing Indigenous souls and remaining the “true religion”.
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    The distribution and relative ecological roles of autotrophic and heterotrophic diazotrophs in the McMurdo Dry Valleys, Antarctica
    (Journal Article, OXFORD UNIV PRESS, 2020-03-01) Coyne, Kathryn J.; Parker, Alexander E.; Lee, Charles Kai-Wu ; Sohm, Jill A.; Kalmbach, Andrew; Gunderson, Troy; Leon-Zayas, Rosa; Capone, Douglas G.; Carpenter, Edward J.; Cary, S. Craig
    The McMurdo Dry Valleys (MDV) in Antarctica harbor a diverse assemblage of mat-forming diazotrophic cyanobacteria that play a key role in nitrogen cycling. Prior research showed that heterotrophic diazotrophs also make a substantial contribution to nitrogen fixation in MDV. The goals of this study were to survey autotrophic and heterotrophic diazotrophs across the MDV to investigate factors that regulate the distribution and relative ecological roles of each group. Results indicated that diazotrophs were present only in samples with mats, suggesting a metabolic coupling between autotrophic and heterotrophic diazotrophs. Analysis of 16S rRNA and nifH gene sequences also showed that diazotrophs were significantly correlated to the broader bacterial community, while co-occurrence network analysis revealed potential interspecific interactions. Consistent with previous studies, heterotrophic diazotrophs in MDV were diverse, but largely limited to lakes and their outlet streams, or other environments protected from desiccation. Despite the limited distribution, heterotrophic diazotrophs may make a substantial contribution to the nitrogen budget of MDV due to larger surface area and longer residence times of lakes. This work contributes to our understanding of key drivers of bacterial.
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