25,322 results for Journal article

  • Storm-driven changes in rip channel patterns on an embayed beach

    Gallop, Shari L.; Bryan, Karin R.; Coco, Giovanni; Stephens, S.A. (2010)

    Journal article
    University of Waikato

    This paper introduces a semi-automatic computer algorithm designed to detect rip current channels in video imagery. As a case study, this method is applied to 3.3 years of video data from an embayed beach to demonstrate the link between antecedent surf zone morphology, wave energy and up/down transitions in beach state. An objective measure of rip channel change was developed to define six significant rip reconfiguration events and relate these events to wave energy. Over the period of study no complete resets of the nearshore morphology occurred. The analysis indicates that direct correlation of rip patterns with the instantaneous wave conditions is not a useful way to demonstrate how rips and waves interact. The average wave energy over a period of ten days, combined with storm duration were good indicators of rip channel change, demonstrating that in general, beach morphology responds with a time lag to changes in forcing. Rip channels with a short cross-shore length and narrow alongshore spacing responded faster to changes in wave conditions than rips with a long cross-shore length and wider alongshore spacing. To force changes in the rip morphology, longer rip channels required wave events of higher energy and/or a longer duration. Offshore islands protect the beach under certain wave approach angles, sometimes resulting in a dual-width surf zone, which was narrow at the sheltered end and wide at the exposed end of the beach. The wider surf zone end was characterised by three dominant and persistent rip channels, whereas the narrow surf zone section contained a number of smaller rips which evolved rapidly under wave forcing. Our observations demonstrate the importance of rip channel size in controlling the response time of nearshore morphology.

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  • Government policies and Indigenous tourism in New Caledonia

    d'Hauteserre, Anne-Marie (2010)

    Journal article
    University of Waikato

    Governments in New Caledonia are supporting ecotourism initiatives as the French state has mandated efforts to increase the income of Kanak people. As it is generally asserted that tourism development provides economic benefits, this article will examine whether tourism (both entrepreneurs and visitors) can treat indigenous cultures and their environment with dignity. It scrutinizes in particular the role of government policies in fostering such an outcome. Post-colonialism, as a theoretical framework, questions existing inequitable power relations and demands a rethinking of the construction of knowledge and accumulation of wealth. In New Caledonia, it took two major Accords for the Kanak to be able to participate in its economic development. Post-colonialism supports the indigenization of the production of destinations. The Kanak do not refute economic development; they want it within the Kanak concept of land use and on their customary lands. The article describes the various efforts of the Northern Province, within the policy framework of the territory of New Caledonia, to foster forms of tourism development that rely on the local market. The accent has been on supporting the development of potentialities before outside investors catch them and on empowering enterprising individuals. Unfortunately, at this stage tourism development in the Northern Province provides some income but has yet truly to elevate livelihoods.

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  • High temperature mechanical properties of Ti-47Al-2Cr (at %) alloy produced using powder compact forging of a mechanically milled powder

    Nadakuduru, Vijay Navaratna; Zhang, Deliang; Cao, Peng; Gabbitas, Brian (2009)

    Journal article
    University of Waikato

    Ultrafine grained (UFG) Ti-47Al-2Cr (at %) alloy was prepared using a combination of high energy ball milling of a mixture of elemental powders to produce a Ti/Al/Cr composite powder and forging of compacts of this composite powder. The microstucture of the powder forged alloy was found to be dependent on the initial condition of the powder. The alloy produced by this method has demonstrated good formability, both in tensile and compression testings at elevated temperatures. A ductility of 80–165% in tension has been observed, while in a compression plastic strain of ~ 50% was found to be easily achievable, without causing cracking. The deformation behaviour of the particular alloy in tension and compression at elevated temperature has been discussed in detail. The results from the present investigation indicate that UFG Ti-47Al-2Cr (at %) alloy produced using powder compact forging has good formability, and is suitable precursor for near-net shaping using thermomechanical processes such as forging and superplastic forming.

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  • The efficacy of systematic desensitization for treating the separation-related problem behaviour of domestic dogs

    Butler, Rynae; Sargisson, Rebecca J.; Elliffe, Douglas (2010)

    Journal article
    University of Waikato

    The evaluation of systematic desensitization to treat separation-related problem behaviours, such as destruction of property, excessive barking, or house-soiling, has tended to rely on single case-studies. Eight dogs exhibiting separation-related behaviour, and their owners, participated in a controlled experiment using a within-subjects design to evaluate the efficacy of a combination of systematic desensitization and counter-conditioning. Treatment produced significant reductions in both the frequency (T(9)) = 0.0, P = 0.008) and the severity (T(9)) = 0.0, P = 0.008) of separation-related behaviours compared to baseline. Six dogs, for which follow-up data were obtained three months after treatment ended, showed almost complete elimination of the problem behaviour. The use of counter-conditioning, and other behavioural advice, did not appear to be related to the success of the treatment, suggesting that systematic desensitization was the critical element. Speed of progress and final success was not related to the consistency with which the owners applied systematic desensitization, indicating that even when owners apply systematic desensitization haphazardly, it can still be successful in treating separation-related behaviour in dogs.

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  • Drymatter content and fruit size affect flavour and texture of novel Actinidia deliciosa genotypes

    Nardozza, Simona; Gamble, Joanna; Axten, Lauren G.; Wohlers, Mark W.; Clearwater, Michael J.; Feng, Jinquan; Harker, F. Roger (2010)

    Journal article
    University of Waikato

    BACKGROUND: Previous studies with commercial kiwifruit cultivars have demonstrated that the taste of fruit with higher dry matter content (DM) is more liked by consumers. A unique replicated trial of kiwifruit genotypes (10 high/low DM × small/large-fruited genotypes) has provided an opportunity to consider how the genetic propensity for a kiwifruit to accumulate DM affects fruit flavour and texture. In the present study, eating-ripe fruit from each of the genotypes were assessed using a trained sensory panel and the relationships between these sensory attributes and fresh weight, DM, flesh firmness and soluble solids content (SSC) were explored. RESULTS: The genotypes provided a diversity of flavour and texture attributes, each of which varied in perceived intensity of the sensory experience. High-DM genotypes had higher SSC and were perceived as sweeter than low-DM genotypes. Sweet taste was closely associated with the perception of the tropical flavour and high-DM genotypes were found to have more tropical notes. Fruit size was associated with fruit texture, and small fruit were characterised by a firmer and more fibrous core. Large high-DM fruit were perceived as juicier than those of all other genotypes. CONCLUSIONS: Genotypes were perceived differently from one another, and differences in fruit size and DM content were reflected in fruit sensorial properties. This study is unique in demonstrating interactions between fruit size, DM and sensory properties. These findings could be relevant not only to kiwifruit but to fruiting crop breeders in general, because of the demonstrated potential for effects of fruit size and DM content on sweetness, flavour and fruit texture.

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  • Modeling of inundation dynamics on Banda Aceh, Indonesia during the great Sumatra tsunamis December 26, 2004

    Prasetya, Gegar Sapta; Borrero, Jose; de Lange, Willem P.; Black, Kerry P.; Healy, Terry R. (2011)

    Journal article
    University of Waikato

    The tsunami inundation flows on Banda Aceh, Indonesia reached 5 km inland during the December 26, 2004, event and devastated most of the houses, buildings, and infrastructure along the coast and killed more than 167,000 people. The overland flows from the northwest coast and the west coast collided at Lampisang village approximately 3.7 km from Ulee Lheue (northwest coast) and 6.8 km from Lhok Nga (west coast) as reported by survivors. Inundation modeling based on the nonlinear shallow-water wave equations reproduces the inundation pattern and demonstrates a colliding of the overland flows. The model suggests that wave characteristics on the northwest coast of Banda Aceh were different from those on the waves that impacted upon the west coast. The areas, which experienced higher inundation levels, did not always experience greatest overland flow speeds, and the damage areas mostly coincide with the flow speed distribution rather than the runup and inundation depth.

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  • Mixed glauconitic-carbonate-siliciclastic surficial sediments on the north Kaipara continental margin, northwestern North Island, New Zealand

    Payne, Danielle Sarah; Nelson, Campbell S.; Hood, Steven D. (2010)

    Journal article
    University of Waikato

    A mosaic of siliciclastic and mixed carbonate-siliciclastic sediments and authigenic minerals occurs at shelf and slope depths (30-1015 m water depth) on the open, wave-dominated north Kaipara continental margin (NKCM) off northern New Zealand. Texture and composition define five surficial sediment facies. Facies 1 (siliciclastic sand) comprises generally well-sorted fine sands that extend to outer shelf depths. Facies 2 (glauconitic sand) is composed of 30-95% authigenic glauconite grains at 150-400 m water depth in central to northern portions of NKCM. Facies 3 (mixed bryozoan-siliciclastic sand) occurs only in northernmost NKCM and involves a conspicuous (>40%) bryozoan carbonate content. Facies 4 (pelletal mud) occupies the mid shelf (100-150 m water depth) in northern NKCM and consists of muddy sediment with >30% mixed carbonate-siliciclastic pellets of probable fecal origin. Facies 5 (foraminiferal mud and sand) contains >30% foraminiferal tests at slope depths in southern NKCM and at both slope and mid-outer shelf depths towards the north. The siliciclastic mineralogy is consistent with mainly distant provenances to the south of the NKCM in central North Island and northern South Island, while much of the bryozoan material is likely reworked from the Three Kings carbonate platform to the north. No single shelf sedimentation model explains the complex facies distributions on the NKCM because the deposits record the interplay of several present and past hydrodynamic and sediment supply controls. While truly modern deposits may occur inshore, the bulk of NKCM surficial sediments are mainly palimpsest and/or relict deposits.

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  • Industrial engineering priorities for improved demand chain performance

    Towill, Denis R.; Childerhouse, Paul (2011)

    Journal article
    University of Waikato

    Purpose – The purpose of this paper is to exploit site-based research evidence from a range of value streams so as to prioritise the industrial engineering (IE) foci necessary to move towards the goal of a seamless demand chain. Design/methodology/approach – A sample of 40 real-world value streams have been audited to produce codified scores assessing the usage of 12 Simplicity Rules leading to streamlined material flow. The rules are partitioned into “local” (Internal) and “holistic” (External) actions. Exploratory statistics are used to explore the different uptake of these two groups. Research limitations/implications – The sample is neither random nor fully representative of all supply chain scenarios. This paper confirms, via site based research, the validity of first actioning the improvements necessary to enable “our process” to deliver efficiently and effectively, in response to internal demands. Practical implications – Expending effort into effective engineering of “our process(es)” as first priority offers a double advantage compared to starting at the systems level. Such a strategy generates both competence and confidence. Once this level is achieved the business is in a good position for upgrading the external interfaces. Originality/value – This paper shows that modern industrial engineering concepts transpose into two groups of Simplicity Rules, which can move a business forward towards the seamless demand chain goal. The rich field data confirm a logical industrial engineering sequence when enhancing demand chain performance.

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  • Does ‘acoustic anchoring’ reduce post-translocation dispersal of North Island robins?

    Bradley, David William; Ninnes, Calum Edward; Valderrama Ortiz, Sandra Viviana; Waas, Joseph R. (2011)

    Journal article
    University of Waikato

    Context: Animal translocations are an important conservation tool; however, post-release dispersal can hinder successful population establishment. Playback of conspecific song attracts dispersing individuals in some species, although its application following animal translocation has yet to be rigorously investigated. Aims: To determine whether conspecific song can be used as an ‘acoustic anchor’, we adopted an experimental approach during the translocation of 60 North Island robins (Petroica longipes). Methods: At one of two release locations, we broadcast song at natural rates from four speakers (4 h per morning), for 9 days following release; we set the second release location as a control where identical conditions were established but no playback occurred. To assess the impact of playback, we monitored speaker and control locations, surveyed tracks around the release areas, and radio-tracked robins over nine playback days and an additional 9 days. Key results: Most robins left both immediate release areas; however, our results showed that (1) more robins (6 birds on 14 of the 18 days), in particular females (3 birds), approached the playback location than the ‘flagged’ control location (3 male birds on 5 of the 18 days), (2) individual robins returned to the playback location repeatedly, unlike those at the control site, and (3) robins also visited the playback location longer after playback than they did silent control locations. In contrast, radio-telemetry data from five robins suggested that general dispersal was not influenced by playback. Two radio-tracked females moved over long distances (some to >3 km from their release location), whereas two radio-tracked males remained relatively close to the release sites. Conclusions: We demonstrated a short-term attraction effect of playback over a period of several weeks for some birds, particularly females. In contrast, we detected fewer birds over a shorter period at the silent control release site, where no females were detected. However, long-term monitoring at both sites suggested that the effect of playback on reducing post-release dispersal was transitory. Implications: The lack of a clear and lasting effect of acoustic anchoring on dispersal in the present study has provided information on the limited utility of song playback as a conservation management tool for this species. Consideration of the species’ ecology and suitability for ‘acoustic anchoring’ must be made before playback is employed as a conservation measure to reduce excess post-translocation dispersal.

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  • Volcano-meteorological tsunamis, thec. AD 200 Taupo eruption (New Zealand) and the possibility of a global tsunami

    Lowe, David J.; de Lange, Willem P. (2000)

    Journal article
    University of Waikato

    Meteorological tsunamis are long-period waves that result from meteorologically driven disturbances. They are also generated by phase coupling with atmospheric gravity waves arising through powerful volcanic activity. The AD 1883 Krakatau eruption generated volcano-meteorological tsunamis that were recorded globally. Because of its extreme violence and energy release (≥150±50 megatons explosive yield), and by analogy with the Krakatau event, it is highly possible that the ignimbrite-emplacement phase of the c. ad 200 Taupo eruption of North Island, New Zealand, generated a similar volcano-meteorological tsunami that may have reached coastal areas worldwide. Tsunami deposits of identical age to the Taupo eruption occur in central coastal New Zealand and probably relate to that event; definitive evidence elsewhere has not yet been found. In theory, volcano-meteorological tsunamis are likely to be produced during comparable eruptive events at other explosive volcanoes, and thus represent an additional volcanic hazard at coastal sites far from source. We suggest that evidence for such tsunamis, both for marine and lacustrine environments, may be preserved in geological records, and that further work searching for this evidence using a facies approach is timely.

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  • Consequences of human-mediated marine intrusions on the zooplankton community of a temperate coastal lagoon

    Duggan, Ian C.; White, Michelle A. (2010)

    Journal article
    University of Waikato

    Barrier bars separating lagoons from oceans are frequently breached as a management tool to prevent flooding of terrestrial ecosystems. The effects of such human-mediated openings on zooplankton have been investigated only in one tropical system. We investigated the temperate Waituna Lagoon, New Zealand, over a 2-year period when the barrier bar was 'artificially' breached on three occasions. Increases in salinity associated with opening of the barrier bars greatly influenced zooplankton community composition, and recovery of communities was dependent on the rate at which salinity returned to pre-disturbance conditions. As such, resilience of zooplankton in coastal lagoons is a function of the lagoon conditions returning to those experienced prior to barrier breach, rather than being a result of the zooplankton community simply recovering from a single defined disturbance event. In contrast to the tropical lagoon studies, temperature in Waituna Lagoon was inferred to explain a significant proportion of the variability in zooplankton community composition, independent of salinity. Appropriate timing for the opening of barrier bars by management authorities in temperate lagoons, which would allow the greatest opportunity for freshwater zooplankton communities to recover rapidly, will rely on determining the best time for rapid barrier bar reformation and high freshwater inflow rates (i.e. the recovery of zooplankton relies on return to initial conditions). However, such an approach is in direct conflict with the opening of barrier bars for management of water levels.

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  • A micromorphological study of pedogenic processes in an evolutionary soil sequence formed on Late Quaternary rhyolitic tephra deposits, North Island, New Zealand

    Bakker, L.; Lowe, David J.; Jongmans, A.G. (1996)

    Journal article
    University of Waikato

    The influence of time as a soil forming factor was studied on an evolutionary sequence of five soils (1850 radiocarbo years BP-ca. 120,000 BP) developed in rhyolitic tephra deposits in New Zealand. New micromorphological observations were combined with existing macromorphological, chemical, textural, and clay mineralogical analyses to assess the extent of polygenesis in the soils. The younger soils (1850 BP to ca. 22,600 BP) are characterised by initial weathering and little secondary mineral formation. This status is expressed by abundant pumice fragments and fresh, easily weatherable minerals, as well as a low clay content with an isotropic character. Comminution and neoformation are the main pedological processes. The older soils (ca. 120,000 BP) are characterised by a high degree of alteration of primary minerals, little or no pumice fragments, clay illuviation, gleying, and a high clay content (>80%) consisting of a range of crystalline clay minerals including halloysite, gibbsite, kaolinite, and vermiculite, plus crystalline iron oxides. Evidence of polygenesis can be observed in the micromorphology of the older soils: (1) the range of secondary minerals is the result of the integration and succession of soil-forming processes through time; (2) the accumulatory character of the tephra deposits has resulted in stronger weathering of the lower horizons than upper horizons because of continuous pedogenesis. Such polygenesis in the older soils supports the view that the older the soil, the more polygenetic it is likely to be.

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  • Measurement of feeding motivation in sheep and the effects of food restriction

    Verbeek, Else; Waas, Joseph R.; McLeay, Lance M.; Matthews, Lindsay R. (2011)

    Journal article
    University of Waikato

    The availability of food is a crucial factor determining the health and growth of animals. Prolonged or severe food restriction will trigger the subjective state of hunger, which could potentially reduce welfare. We refined a methodology for the measurement of feeding motivation as an indicator of hunger, evaluated the effects of food restriction on feeding motivation in ewes (Ovis aries) and applied a behavioural demand analysis to the data. Sixteen ewes were exposed to five different cost levels (i.e., 2, 6.6, 12.1, 22, or 40 m walking distances per reward) and two feeding levels (24 h restriction and an un-restricted control). We found that 24 h restricted ewes worked for a higher number of rewards (P < 0.001), walked a greater total distance (P < 0.001) and approached the feeding station faster on the first visit (P < 0.001). Therefore, the methodology was able to detect differences in feeding motivation between restricted and control ewes and is a potential indirect indicator of hunger. A generic demand function fitted to the data showed that the elasticity of demand, the maximum price paid (Pmax) and maximum expenditure (Omax) were not sensitive indicators of motivation, probably because we did not generate a complete demand curve. Imposing a cost by providing sheep with the opportunity to walk for their food could be a valuable tool in establishing acceptable feeding levels from an animals’ perspective. However, more research on validating behavioural demand measures as indicators of motivation is needed.

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  • Controlled intoxication: the self-monitoring of excessive alcohol use within a New Zealand tertiary student sample

    McEwan, Brett James; Swain, David; Campbell, Maxine M. (2011)

    Journal article
    University of Waikato

    Aims: Drawn from a study aimed at exploring students’ drinking behaviour and attitudes, this article focuses upon findings that revealed how heavy-drinking students monitored and managed their experiences of alcohol intoxication. Methods: 819 students residing within three university student residences were invited to participate in three phases of data collection. Utilising a combination of qualitative and quantitative research methods, a total of 15 focus group interviews and 18 indepth interviews were undertaken, and 501 students (61%) completed a written survey questionnaire. Results: Sixty percent of students agreed with the statement “I usually know beforehand if I am going to get drunk”. One-half of male drinkers and one-third of female drinkers reported they were intoxicated on a weekly basis. When drinking to intoxication, the majority of students monitored a range of drinking effects (a total of 14 were identified) which they considered were signals for the need to either slow down or stop drinking. Conclusions: The majority of drinkers in this study who consume alcohol with the intention of getting intoxicated, typically drink to a predetermined level of intoxication, and maintain that level by monitoring a range of drinking effects—this behaviour has been termed controlled intoxication. Future harm-minimisation strategies could be developed that encourage heavy-drinkers to adopt ‘safer’ drinking-effect signals as indicators to slow down or stop drinking.

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  • Reformed and engaged boards – not activist shareholders

    Ingley, Coral; Rennie, Morina; Mueller, Jens; Cocks, Graham; Warrick, Donald D.; Erakovic, Liljana (2011)

    Journal article
    University of Waikato

    This study considers the legitimacy of shareholder activism as a means of exercising influence in the corporate decision-making process and identifies self-reformed boards as a superior solution to the issues that activists attempt to address. We conceptualise the board of directors' role as representing the interests of multiple principals. When any one principal is able to serve its own interests by influencing corporate decision-making through shareholder activism, other principals' interests may be compromised. We argue that a better long-term solution lies not with activist shareholders, but with culturally reformed boards. We suggest a set of self-reform initiatives that would help them to achieve their potential. We develop a conceptual framework for the arguments in favour of boards taking a leadership role in corporate engagement with shareholders and stakeholders. To the extent that boards are unable to implement self-reform, governments may need to develop public policy initiatives for corporate governance reform.

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  • Laptops for teachers: practices and possibilities

    Cowie, Bronwen; Jones, Alister; Harlow, Ann (2011)

    Journal article
    University of Waikato

    The Laptops for Teachers scheme in New Zealand provides teachers whose schools opt into the scheme access to a laptop for their exclusive use. This paper reports on the findings of the three‐year evaluation of the impact of the laptops on secondary teachers’ work. The findings indicate that school leadership has been pivotal to the provision of the technological infrastructure and organisational support needed for teacher use of the laptops. Departmental leadership has been crucial in supporting teacher use of laptops for teaching and learning. Teachers described gains in expertise, indicating that they used the laptop for a range of purposes to support their teaching. These included lesson planning and preparation, and reporting. Where teachers had easy access to a laptop‐plus‐data projector they found that students responded to material that included images and up‐to‐date real‐world examples. Colleagues were identified as the main source of professional development for the use of the laptop for teaching purposes. The findings of the study suggest schools are advised to consider how to support teachers to work collaboratively to share expertise as a way of supporting and extending teacher use of laptops.

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  • Sustainable development: what it means to CFOs of New Zealand

    Dimitrov, Dara K.; Davey, Howard (2011)

    Journal article
    University of Waikato

    Purpose – The purpose of this research is to evaluate and better understand the Chief Financial Officers' (CFOs) role in sustainability reporting of New Zealand's (NZ) publicly listed companies. Design/methodology/approach – The research uses a questionnaire sent to the CFOs of 88 of New Zealand's largest listed companies; the CFOs were telephoned beforehand and introduced to the nature of the research and asked if they would participate. A total of 33 fully completed responses were returned. Findings – CFOs expressed their agreement with the adoption of sustainable development as they believed there were benefits to be made for their firms; the survey identified reputation enhancement and good corporate governance as the two main benefits. However they were reluctant to have their firms' information scrutinised by stakeholders. They believed that stakeholders are largely unaware of the difficulties of adopting sustainable development practices, and furthermore, stakeholders have unrealistic expectations of what their firms could achieve by adopting sustainable development. CFOs did not believe that sustainable development would cut costs and improve their profits – rather they believed that sustainable development adoption was very inconvenient as it is costly. Thus the influence for firms to adopt sustainable development practices is driven largely by non-financial factors rather than any economic gains. This corroborates earlier findings. Research limitations/implications – The research utilises primary data collected in 2008. A useable response rate of 38 per cent was achieved. The research is restricted to New Zealand listed companies. Practical implications – In gaining a deeper appreciation of where CFOs gain their understanding of sustainable development issues, and how they participate in the discourse around sustainable development, we are potentially better able to provide information to this key group of people. Originality/value – Very little research has been undertaken into how CFOs gain their knowledge about sustainability reporting nor about their views on the subject. This research attempts to fill this gap and opens the way for similar work to be undertaken overseas.

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  • Mechanical behaviour of Titanium, Ti-6Al-4V (wt %) alloy and Ti-47Al-2Cr (at %) alloy produced using powder compact forging

    Nadakuduru, Vijay Navaratna; Zhang, Deliang; Raynova, Stiliana (Stella) Rousseva; Cao, Peng; Gabbitas, Brian (2011)

    Journal article
    University of Waikato

    Powder compact forging was used to produce bulk consolidated titanium and Ti-6Al-4V (wt %) and Ti-47Al-2Cr (at%) alloy disks from hydrogenated and dehydrogenated (HDH) and gas atomised powders (GA) powders (in the case of titanium and Ti-6Al-4V) and a mechanically milled powder (in the case of Ti-47Al-2Cr alloy). The bulk titanium and Ti-6Al-4V (wt %) alloy have been produced by forging of the powder compacts. The Ti-47Al-2Cr (at %) alloy was produced using canned powder compact forging of a Ti/Al/Cr composite powder. The purpose of the present study is to investigate the deformation and fracture behaviour of the bulk consolidated as-forged materials, by conducting tensile testing at room temperature (RT) and examination of the fractured specimens which had near-α, α + β and γ phase structures, respectively. It was found that as-forged bulk titanium disk produced using HDH powder showed a yield point with a yield strength of ~700 MPa and with a considerable amount of ductility. While the as-forged Ti-6Al-4V (wt %) alloy produced using HDH powder, fractured prematurely without any yielding. On the other hand yielding was observed in the as-forged Ti-6Al-4V (wt %) alloy produced using GA powder, showing a yield strength of ~970 MPa and a considerable amount of plastic strain to fracture. The bulk consolidated Ti-47Al-2Cr (at %) alloy also fractured prematurely with fracture strength of ~125 MPa. The mechanical behaviour of the as-forged bulk materials was found to be dependent on several factors such as initial powders used, green density of the powder compact, forging parameters used during forging. It was expected that the entrapped gas in green compacts, absorbed oxygen, porosity and inter-particle bonding play an important role on the quality of the as-forged material, which in turn affected the mechanical behaviour of the bulk material.

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  • Behavior-based assessment of the auditory abilities of brushtail possums

    Osugi, Mizuho; Foster, T. Mary; Temple, William; Poling, Alan (2011)

    Journal article
    University of Waikato

    Brushtail possums (Trichosurus vulpecula) were trained to press a right lever when a tone was presented (a tone-on trial) and a left lever when a tone was not presented (a tone-off trial) to gain access to food. During training the tone was set at 80 dB(A), with a frequency of 0.88 kH for 3 possums and of 4 kH for the other 2. Once accuracy was over 90% correct across five consecutive sessions, a test session was conducted where the intensity of the tone was reduced by 8 dB(A) over blocks of 20 trials until accuracy over a block fell below 60%. After each test session, training sessions were reintroduced and continued until accuracy was again over 90%, when another test session was conducted. This process continued until there were at least five test sessions at that tone frequency. The same procedure was then used with frequencies of 0.20, 0.88, 2, 4, 10, 12.5, 15, 20, 30, and 35 kHz. Percentage correct and d9 decreased approximately linearly for all possums as tone intensity reduced. Both sets of lines were shallowest at the higher frequencies and steepest at the lower frequencies. Hit and false alarm rates mirrored each other at high frequencies but were asymmetric at lower frequencies. Equal d9 contours showed that sensitivity increased from 2 to 15 kHz and continued to be high over 20 to 35 kHz. The possums remained sensitive to the 20 to 35 kHz tones even at low intensities. The present study is the first to report the abilities of possum to detect tones over this range of frequencies and its results support the findings of a microelectrode mapping survey of possums’ auditory cortex.

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  • The Education and training of clinical medical physicists in 25 European, 2 North American and 2 Australasian countries: Similarities and differences

    Stefanoyiannis, Antonis P.; Prentakis, A.; Christofides, Stelios; Gerogiannis, I.; Round, W. Howell; Geronikola-Trapali, Xenia; Armeniakos, Ioannis; Kaplanis, Prodromos A.; Chatziioannou, S. N. (2011)

    Journal article
    University of Waikato

    Purpose: The clinical medical physicist is part of a team responsible for safe and competent provision of radiation-based diagnostic examinations and therapeutic practices. To ensure that the physicist can provide an adequate service, sufficient education and training is indispensable. The aim of this study is to provide a structured description of the present status of the clinical medical physicist education and training framework in 25 European, 2 North American and 2 Australasian countries. Methods: For this study, data collection was based on a questionnaire prepared by the European Federation of Organizations in Medical Physics (EFOMP) and filled-in either by the corresponding scientific societies-organizations or by the authors. Results: In the majority of cases, a qualified medical physicist should have an MSc in medical physics and 1–3 years of clinical experience. Education and training takes place in both universities and hospitals and the total duration of the programs ranges from 2.5 to 9 years. In 56% of all European countries, it is mandatory to hold a diploma or license to work as a medical physicist, the situation being similar in Australasian and 4 states of USA. Generally, there are national registers of medical physicists with inclusion on the register being voluntary. There are renewal mechanisms in the registers usually based on a Continuing Professional Development (CPD) system. Conclusions: In conclusion, a common policy is followed in general, on topics concerning education and training as well as the practice of the medical physicist profession, notwithstanding the presence of a few differences.

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