title: Yield of cyclic vs heat-and-hold induction sintering on the mechanical behaviour of the low-cost Ti-5Fe alloy

authors: Bolzoni, Leandro

abstract: The high cost of Ti alloys is hindering their industrial implementation and, therefore, the quest for low-cost Ti alloys entails lowering the intrinsic cost using cheaper alloying elements and developing more efficient manufacturing methods. In this study, the yield of manufacturing the novel low-cost Ti-5Fe alloy via heat-and-hold and cyclic induction sintering around the allotropic α→β phase transformation was compared as the latter is expected to enhance densification. It is demonstrated that induction sintering is extremely efficient due to its characteristic high heating rates and simultaneously permits to obtain homogenous chemical compositions at low homologous sintering temperatures. Cyclic sintering yields faster sintering kinetics, which results in higher densification with respect to heat-and-hold, achieving uniform residual porosity distributions within the microstructure, comparable relative density, and on average smaller and more spherical pores. Consequently, higher strength but not necessarily higher ductility is obtained for the cyclic sintered Ti-5Fe alloy as the failure mode entails crack propagation through irregularly shaped pores.

text: Yield of cyclic vs heat-and-hold induction sintering on the mechanical behaviour of the low-cost Ti-5Fe alloy The high cost of Ti alloys is hindering their industrial implementation and, therefore, the quest for low-cost Ti alloys entails lowering the intrinsic cost using cheaper alloying elements and developing more efficient manufacturing methods. In this study, the yield of manufacturing the novel low-cost Ti-5Fe alloy via heat-and-hold and cyclic induction sintering around the allotropic α→β phase transformation was compared as the latter is expected to enhance densification. It is demonstrated that induction sintering is extremely efficient due to its characteristic high heating rates and simultaneously permits to obtain homogenous chemical compositions at low homologous sintering temperatures. Cyclic sintering yields faster sintering kinetics, which results in higher densification with respect to heat-and-hold, achieving uniform residual porosity distributions within the microstructure, comparable relative density, and on average smaller and more spherical pores. Consequently, higher strength but not necessarily higher ductility is obtained for the cyclic sintered Ti-5Fe alloy as the failure mode entails crack propagation through irregularly shaped pores.

year: 2025-06

title: Time Perception: A Test of Weber's Law in Possums

authors: Lockhart, Rachael Anne

abstract: The performance of brushtail possums, Trichosurus vulpecula, was investigated in two experiments that used the peak procedure to investigate their ability to time. For Experiment 1 five possums lever pressed for food reinforcers on 3 different Fixed Interval (FI) schedules that included FI 15-s, FI 30-s and FI 60-s. The possums also experienced Peak Interval (PI) schedules that did not provide reinforcement for 20% of trials. The PI trials were 3 times longer than the FI schedule that was in effect on the other 80% of trials when responding was reinforced. Response rates increased to a maximum at about the time the responses were normally reinforced on FI trials and then decreased to a minimum at around 2 times the FI schedule duration that was in effect on a given condition. When relative response rates were plotted as a function of relative time the distributions generally superposed for the ascending, but not descending portions of the function. There was evidence of resurgence in response rates towards the end of the PI trials. The amount of resurgence appeared to be a function of the amount of experience animals had with the schedule and decreased across days, however, it was never eliminated. In Experiment 2, five possums lever pressed for food reinforcers on an FI 30-s schedule. Once again on 80% of trials responding was reinforced. For the other 20% of trials, responding was not reinforced and trials lasted either 3 (Experiment 2, Condition 1) or 10 (Experiment 2, Condition 2) times longer than the FI schedule that was in effect, and these extinction trials ended automatically when the specific time had passed. Resurgence was still evident at the end of the PI trials when they were 3 times longer than the FI, but decreased dramatically when they were 10 times longer than the FI that was in effect, resulting in the conclusion that that resurgence was dependent on the duration of the PI trials.

text: Time Perception: A Test of Weber's Law in Possums The performance of brushtail possums, Trichosurus vulpecula, was investigated in two experiments that used the peak procedure to investigate their ability to time. For Experiment 1 five possums lever pressed for food reinforcers on 3 different Fixed Interval (FI) schedules that included FI 15-s, FI 30-s and FI 60-s. The possums also experienced Peak Interval (PI) schedules that did not provide reinforcement for 20% of trials. The PI trials were 3 times longer than the FI schedule that was in effect on the other 80% of trials when responding was reinforced. Response rates increased to a maximum at about the time the responses were normally reinforced on FI trials and then decreased to a minimum at around 2 times the FI schedule duration that was in effect on a given condition. When relative response rates were plotted as a function of relative time the distributions generally superposed for the ascending, but not descending portions of the function. There was evidence of resurgence in response rates towards the end of the PI trials. The amount of resurgence appeared to be a function of the amount of experience animals had with the schedule and decreased across days, however, it was never eliminated. In Experiment 2, five possums lever pressed for food reinforcers on an FI 30-s schedule. Once again on 80% of trials responding was reinforced. For the other 20% of trials, responding was not reinforced and trials lasted either 3 (Experiment 2, Condition 1) or 10 (Experiment 2, Condition 2) times longer than the FI schedule that was in effect, and these extinction trials ended automatically when the specific time had passed. Resurgence was still evident at the end of the PI trials when they were 3 times longer than the FI, but decreased dramatically when they were 10 times longer than the FI that was in effect, resulting in the conclusion that that resurgence was dependent on the duration of the PI trials.

year: 2011

title: "It's about empowering the whānau": Māori adult students succeeding at university

authors: Williams, Daphne Christina (Tina)

subjects: māori academic success

abstract: A large number of studies have demonstrated that Māori students are not performing well in education. The literature in the general area of Māori education paints a very grim picture that demonstrates a clear preoccupation with failure and underachievement. These studies often overlook the experiences of Māori adult students who return to study long after leaving school and experience considerable success. This paper focuses on the academic success of 16 indigenous students at a New Zealand university. It is based on the findings of a qualitative investigation that explored the experiences of Māori adult students who entered university with very few formal school qualifications and then went on to attain undergraduate degrees. This paper pays particular attention to the role of the whānau in facilitating Māori educational success at university.

text: "It's about empowering the whānau": Māori adult students succeeding at university A large number of studies have demonstrated that Māori students are not performing well in education. The literature in the general area of Māori education paints a very grim picture that demonstrates a clear preoccupation with failure and underachievement. These studies often overlook the experiences of Māori adult students who return to study long after leaving school and experience considerable success. This paper focuses on the academic success of 16 indigenous students at a New Zealand university. It is based on the findings of a qualitative investigation that explored the experiences of Māori adult students who entered university with very few formal school qualifications and then went on to attain undergraduate degrees. This paper pays particular attention to the role of the whānau in facilitating Māori educational success at university.

year: 2011