Magnetospheric Structure and Atmospheric Joule Heating of Habitable Planets Orbiting M-dwarf Stars

We study the magnetospheric structure and the ionospheric Joule Heating of planets orbiting M-dwarf stars in the habitable zone using a set of magnetohydrodynamic models. The stellar wind solution is used to drive a model for the planetary magnetosphere, which is coupled with a model for the planetary ionosphere. Our simulations reveal that the space environment around close-in habitable planets is extreme, and the stellar wind plasma conditions change from sub- to super-Alfvénic along the planetary orbit. As a result, the magnetospheric structure changes dramatically with a bow shock forming in the super-Alfvénic sectors, while no bow shock forms in the sub-Alfvénic sectors. The planets reside most of the time in the sub-Alfvénic sectors with poor atmospheric protection. A significant amount of Joule Heating is provided at the top of the atmosphere as a result of the intense stellar wind. For the steady-state solution, the heating is about 0.1%-3% of the total incoming stellar irradiation, and it is enhanced by 50% for the time-dependent case. The significant Joule Heating obtained here should be considered in models for the atmospheres of habitable planets in terms of the thickness of the atmosphere, the top-side temperature and density, the boundary conditions for the atmospheric pressure, and particle radiation and transport. Here we assume constant ionospheric Pedersen conductance similar to that of the Earth. The conductance could be greater due to the intense EUV radiation leading to smaller heating rates. We plan to quantify the ionospheric conductance in future study.

50,000-years of vegetation and climate change in the southern Namib Desert, Pella, South Africa

This paper presents the first continuous pollen record from the southern Namib Desert spanning the last 50,000 years. Obtained from rock hyrax middens found near the town of Pella, South Africa, these data are used to reconstruct vegetation change and quantitative estimates of temperature and aridity. Results indicate that the last glacial period was characterised by increased water availability at the site relative to the Holocene. Changes in temperature and potential evapotranspiration appear to have played a significant role in determining the hydrologic balance. The record can be considered in two sections: 1) the last glacial period, when low temperatures favoured the development of more mesic Nama-Karoo vegetation at the site, with periods of increased humidity concurrent with increased coastal upwelling, both responding to lower global/regional temperatures; and 2) the Holocene, during which time high temperatures and potential evapotranspiration resulted in increased aridity and an expansion of the Desert Biome. During this latter
period, increases in upwelling intensity created drier conditions at the site.
Considered in the context of discussions of forcing mechanisms of regional climate change and environmental dynamics, the results from Pella stand in clear contrast with many inferences of terrestrial environmental change derived from regional marine records. Observations of a strong precessional signal and interpretations of increased humidity during phases of high local summer insolation in the marine records are not consistent with the data from Pella. Similarly, while high percentages of Restionaceae pollen has been observed in marine sediments during the last glacial period, they do not exceed 1% of the assemblage from Pella, indicating that no significant expansion of the Fynbos Biome has occurred during the last 50,000 years. These findings pose interesting questions regarding the nature of environmental change in southwestern Africa, and the significance of the diverse records that have been obtained from the region.

Effect of the interaction layer on the mechanical properties of Ti–6Al–4V alloy castings

The interaction between the face coat material of a mould and the titanium alloy will cause oxygen penetration during the casting and solidification process, resulting in the formation of an α-case interaction layer at the metal surface that influences the mechanical properties of the cast components. In this study, the influence of α-case thickness and loading positions in a Ti–6Al–4V (Ti64) alloy on metal hardness, impact properties and bending strength was investigated. The results showed that the metal surface α-case consisted of many coarse α laths which has a higher hardness than metal matrix. The mechanical properties of the alloy are influenced by the α-case. The alloy bending strength was observed to have changed linearly with the thickness of sample.

The Value of Full Scale Prototype Data - Testing Oyster 800 at EMEC, Orkney

This paper demonstrates the unparalleled value of full scale data which has been acquired from ocean trials of Aquamarine Power’s Oyster 800 Wave Energy Converter (WEC) at the European Marine Energy Centre (EMEC), Orkney, Scotland.
High quality prototype and wave data were simultaneously recorded in over 750 distinct sea states (comprising different wave height, wave period and tidal height combinations) and include periods of operation where the hydraulic Power Take-Off (PTO) system was both pressurised (damped operation) and de-pressurised (undamped operation).
A detailed model-prototype correlation procedure is presented where the full scale prototype behaviour is compared to predictions from both experimental and numerical modelling techniques via a high temporal resolution wave-by-wave reconstruction. This unquestionably provides the definitive verification of the capabilities of such research techniques and facilitates a robust and meaningful uncertainty analysis to be performed on their outputs.
The importance of a good data capture methodology, both in terms of handling and accuracy is also presented. The techniques and procedures implemented by Aquamarine Power for real-time data management are discussed, including lessons learned on the instrumentation and infrastructure required to collect high-value data.

Corrosion Fatigue Behaviour of Laser-welded Shape Memory NiTi Wires in a Simulated Body Fluid

Corrosion fatigue is a fracture process as a consequence of synergistic interactions between the material structure, corrosive environment and cyclic loads/strains. It is difficult to be detected and can cause unexpected failure of engineering components in use. This study reveals a comparison of corrosion fatigue behaviour of laser-welded and bare NiTi wires using bending rotation fatigue (BRF) test coupled with a specifically-designed corrosion cell. The testing medium was Hanks’ solution (simulated body fluid) at 37.5 oC. Electrochemical impedance spectroscopic (EIS) measurement was carried out to monitor the change of corrosion resistance of sample during the BRF test at different periods of time. Experiments indicate that the laser-welded NiTi wire would be more susceptible to the corrosion fatigue attack than the bare NiTi wire. This study can serve as a benchmark for the product designers and engineers to understand the corrosion fatigue behaviour of the NiTi laser weld joint and determine the fatigue life safety factor for NiTi medical devices/implants involving laser welding in the fabrication process.

The Promise of Peace:Revisiting the Northern Irish Model

The Northern Ireland peace process is often eulogized as a successful model of conflict transformation. Although the process exhibited many of the problems that beset other societies seeking to move from conflict to a negotiated peace (including disagreements over the functioning of institutions and the meanings of cultural symbols, unresolved issues relating to the effects of political violence on victims and survivors and society at large; and the residual presence of violent and political ‘spoiler’ groups), the resilience of political dialogue has proven remarkable.
This collection revisits the promise of ‘a truly historic opportunity for a new beginning’ a decade and a half on from the signing of the Belfast/Good Friday Agreement in 1998. The book will bring together academics from across a number of disciplines, including management and organizational behaviour, law, politics, sociology, archaeology and literature.

The different contributions aim to assess what impact it has made in the legal, policy, and institutional areas it specifically targeted: political reform, human rights and equality provision, working through legacies of the past (including police reform, prisoner release and victims' rights) and the building of new relationships within the island of Ireland and between Ireland and Britain. With the emergence of first-time voters who had no direct experience of the violence the book explores what the Agreement offers for future generations.

The book is the culmination of a 12-month research project sponsored by the British Academy and Leverhulme that addressed the following aspects of the peace process:
Peace walls: The euphemistically named peace walls remain one of the most visible reminders of Northern Ireland’s divisions and they are famously the only material manifestations of the conflict that have grown in number and extent since the 1998 Agreement. They were originally placed between antagonistic neighbouring communities – often at their request – at times of heightened tensions. Research under this theme explored the lack of ongoing engagement with their continuing presences, evolving meanings and impact on the communities that reside beside them needs to be overtly addressed.
Cultural division: Cultural differences have often been seen as lying at the heart of the ‘Irish problem’. Despite this, art and artists have increasingly been seen as having the potential to develop new discourses. Research explored the following questions: What role can the arts play in re-imagining the spaces opened up by the promises of the 1998 Agreement? What implication does the confrontation with the legacies of conflict have for artistic practices? What impact do the arts have on constructions of identity, on narratives of history, and on electoral politics?
Institutional transformation: This strand of research explored the significance of the process of organizational change which followed the establishment of the 1998 on political and other public policy institutions such as the police and prison services. It suggested that the experience and lessons learned from such periods of transition have much to contribute to how Northern Ireland begins to address political polarization in other areas of public service infrastructure, chiefly around the sectarian monoliths of education and housing.
Working through the past: ‘Legacy’ issues have gained increasing prominence since 1998: issues to do with public symbolism (particularly relating to the flying of flags and parading), defining victimhood, securing victims’ rights, recovery of the ‘disappeared’, reintegrating ex- prisoners back into society, and the possibilities for truth recovery and reconciliation have all acquired salient and emotive force. Although the 1998 Agreement promised to ‘honour the dead’ through a ‘new beginning’, it is increasingly unclear as to whether an agreed narrative about the past is possible – or even worthwhile pursuing. Research under this theme looked at the complex relationship between memory, commemoration and violence; how commemorative events are performed, organized, policed and represented. It also addressed the fraught issue of how to come to terms with Northern Ireland’s divided and bloodied past.

The editors are in the process of guiding contributors to adapt their papers, which were presented to a series of workshops on the above themes, to the purposes of the book. In particular, the contributors will be guided to focus on the related aims of assessing the extent of change that has occurred and providing an assessment of what remains to be done. To that end, contributors are asked to engage directly with the questions that close the ‘Introduction’, namely: To what extent has the ‘promise’ of the 1998 Agreement been fulfilled? To what extent has the 1998 Agreement given rise to forms of exclusion? To what extent has the 1998 Agreement shaped new forms of debate, dispute and engagement? In the absence of that guidance having been sent out yet, the outlines below are, for the time being, the abstracts of their original papers.