title: A Review of the Dynamics and Oscillations of the Atmosphere

authors: Ross, Joseph

subjects: fluid dynamics

abstract: The atmosphere is a complex, dynamic system and the weather depends on its state. There are many different phenomena that affect the state of the atmosphere - some only involve the atmosphere, others involve the interaction between the atmosphere and the ocean. These phenomena can be modelled using many equations originating from fluid dynamics and thermodynamics, and many of them are considered here. Energy travels around the atmosphere in the form of waves, such as Kelvin waves and Rossby waves. It is possible for a triad of Rossby waves to interact with each other in a way such that resonance occurs. A computer simulation investigating the sensitivity of such waves to turbulence was completed, and it was found that the energetic dominance of the resonant triad does not persist, and the greater the turbulence added to the Rossby triad, the earlier in the integration the instabilities occur.

text: A Review of the Dynamics and Oscillations of the Atmosphere The atmosphere is a complex, dynamic system and the weather depends on its state. There are many different phenomena that affect the state of the atmosphere - some only involve the atmosphere, others involve the interaction between the atmosphere and the ocean. These phenomena can be modelled using many equations originating from fluid dynamics and thermodynamics, and many of them are considered here. Energy travels around the atmosphere in the form of waves, such as Kelvin waves and Rossby waves. It is possible for a triad of Rossby waves to interact with each other in a way such that resonance occurs. A computer simulation investigating the sensitivity of such waves to turbulence was completed, and it was found that the energetic dominance of the resonant triad does not persist, and the greater the turbulence added to the Rossby triad, the earlier in the integration the instabilities occur.

year: 2012

title: Joint effect of β-eutectoid content and heat treatment on the properties of binary Ti-Cu and Ti-Mn alloys

authors: Bolzoni, Leandro

subjects: Titanium alloys

abstract: The use of cheap alloying elements and alternative manufacturing techniques are two strategies that can be used to reduce the high cost of Ti alloys. Furthermore, heat treatments are an easy and cost effective method to tailor the mechanical behaviour by means of the modification of the microstructure. For that, this work analysed the quenching and aging heat treatment of binary Ti-Cu and Ti-Mn alloys manufactured via powder metallurgy. It is found that the post-processing solution treatment does not significantly affect the physical properties and residual porosity remains unchanged within the microstructure; however, the heat treatment changes the microconstituents. Serrated martensitic transformed β is formed in quenched Ti-Cu alloys and it is converted into a coarse lamellar or a hypoeutectoid structure as the Cu content increases with the subsequent aging treatment. Aging of the Ti-Mn alloys slightly coarsen the microstructural features where martensite or equiaxed metastable β grains are obtained after quenching. Enhancing of the mechanical behaviour is generally achieved and the solution treatment switches from improving the ductility to increasing the strength and the hardness as the amount of the alloying element increases.

text: Joint effect of β-eutectoid content and heat treatment on the properties of binary Ti-Cu and Ti-Mn alloys The use of cheap alloying elements and alternative manufacturing techniques are two strategies that can be used to reduce the high cost of Ti alloys. Furthermore, heat treatments are an easy and cost effective method to tailor the mechanical behaviour by means of the modification of the microstructure. For that, this work analysed the quenching and aging heat treatment of binary Ti-Cu and Ti-Mn alloys manufactured via powder metallurgy. It is found that the post-processing solution treatment does not significantly affect the physical properties and residual porosity remains unchanged within the microstructure; however, the heat treatment changes the microconstituents. Serrated martensitic transformed β is formed in quenched Ti-Cu alloys and it is converted into a coarse lamellar or a hypoeutectoid structure as the Cu content increases with the subsequent aging treatment. Aging of the Ti-Mn alloys slightly coarsen the microstructural features where martensite or equiaxed metastable β grains are obtained after quenching. Enhancing of the mechanical behaviour is generally achieved and the solution treatment switches from improving the ductility to increasing the strength and the hardness as the amount of the alloying element increases.

year: 2024

title: Editorial

authors: Clarkin-Phillips, Jeanette

abstract: As New Zealand contemplates wholesale review of the formal schooling system and the leadership implications thereof, the winds of educational change begin to swirl. Not the persistent, yet gentle flutter of change that evolves the educational landscape in almost imperceptible ways, but tumultuous paradigmatic gales that potentially change it beyond all recognition. Heralded by politicians, economists and capitalists, there is little doubt that the 1989 neoliberal tempest wrought havoc on notions of community and profession. The whirlwind shift from social democracy to market competition, managerialism and performativity saw critical voices silenced and educators disparagingly positioned as self-interested providers. In the rush to legislate Tomorrow’s Schools, 18,000 submissions remained unanalysed and therein lies a crucial lesson: we ignore research at our peril. As educators, we have a moral obligation to generate, disseminate and critique understandings of leadership, policy and practice; to remain open to counter perspectives; and to contribute positively and hopefully to research that empowers and emancipates. Consistent with JELPP’s commitment to honouring diversity in leadership focus, setting, and authorship, articles in this year’s general edition offer fresh insight into topics of interconnected and perennial importance: native knowledge, instructional leadership, indigenous teachers, appraisal, professional values, and safe schools.

text: Editorial As New Zealand contemplates wholesale review of the formal schooling system and the leadership implications thereof, the winds of educational change begin to swirl. Not the persistent, yet gentle flutter of change that evolves the educational landscape in almost imperceptible ways, but tumultuous paradigmatic gales that potentially change it beyond all recognition. Heralded by politicians, economists and capitalists, there is little doubt that the 1989 neoliberal tempest wrought havoc on notions of community and profession. The whirlwind shift from social democracy to market competition, managerialism and performativity saw critical voices silenced and educators disparagingly positioned as self-interested providers. In the rush to legislate Tomorrow’s Schools, 18,000 submissions remained unanalysed and therein lies a crucial lesson: we ignore research at our peril. As educators, we have a moral obligation to generate, disseminate and critique understandings of leadership, policy and practice; to remain open to counter perspectives; and to contribute positively and hopefully to research that empowers and emancipates. Consistent with JELPP’s commitment to honouring diversity in leadership focus, setting, and authorship, articles in this year’s general edition offer fresh insight into topics of interconnected and perennial importance: native knowledge, instructional leadership, indigenous teachers, appraisal, professional values, and safe schools.

year: 2019