Evaluation of Cyclic Deformation Behavior of Laser-welded Shape Memory NiTi Alloys at Different Working Temperatures

Post-weld heat-treatment (PWHT) has been established as one of the cost-effective ways to improve the functional properties, namely shape memory and super-elastic effects (SME and SE), of laser-welded NiTi alloys. However, the functional performance of the laser-welded joint at different working temperatures has not been explored yet. The purpose of this study is to investigate the effect of different working temperatures on the functional properties of the laser-welded NiTi alloys before and after PWHT by applying cyclic deformation tests. Two laser-welded samples: as-welded and heat-treated sample (after PWHT at 350 oC or 623 K) were tested in this work at room temperature, 50 oC (or 323 K) and 75 oC (or 348 K) respectively. The samples were cyclically loaded and unloaded for 10 cycles up to 4 % strain. The critical stress to induce the martensitic transformation and the residual strain after the cyclic tests were recorded. The results indicate that the heat-treated sample exhibited better functional properties than the as-welded sample at room temperature and 50 oC (or 323 K). However, both the as-welded and heat-treated samples failed in the cyclic tests at 75 oC (or 348 K). These findings are important to determine the feasible working temperature range for the laser-welded NiTi components to exhibit desirable functional properties in engineering applications involving cyclic loading.

The Routledge Guide to Interviewing: Oral History, Social Enquiry & Investigation

The Routledge Guide to Interviewing sets out a well-tested and practical approach and methodology: what works, difficulties and dangers to avoid and key questions which must be answered before you set out. Background methodological issues and arguments are considered and drawn upon but the focus is on what is ethical, legally acceptable and productive:
-Rationale (why, what for, where, how)
-Ethics and Legalities (informed consent, data protection, risks, embargoes)
-Resources (organisational, technical, intellectual)
-Preparation (selecting and approaching interviewees, background and biographical research, establishing credentials, identifying topics)
-Technique (developing expertise and confidence)
-Audio-visual interviews
-Analysis (modes, methods, difficulties)
-Storage (archiving and long-term preservation)
-Sharing Resources (dissemination and development)

From death row to the mansion of a head of state, small kitchens and front parlours, to legislatures and presbyteries, Anna Bryson and Seán McConville’s wide interviewing experience has been condensed into this book. The material set out here has been acquired by trial, error and reflection over a period of more than four decades. The interviewees have ranged from the delightfully straightforward to the painfully difficult to the near impossible – with a sprinkling of those that were impossible.
Successful interviewing draws on the survival skills of everyday life. This guide will help you to adapt, develop and apply these innate skills. Including a range of useful information such as sample waivers, internet resources, useful hints and checklists, it provides sound and plain-speaking support for the oral historian, social scientist and investigator.

'Whatever You Say, Say Nothing' : Researching Memory & Identity in Mid-Ulster, 1945-1969

The influence of collective memory on political identity in Ireland has been well documented. It has particular force in Northern Ireland where there is fundamental disagreement about how and why the conflict erupted and how it should be resolved. This article outlines some of the issues encountered by an ‘insider’ when attempting to record and analyse the conflicting memories of a range of Protestants and Catholics who grew up in Mid-Ulster in the decades preceding the Troubles. In particular, it considers the challenges and opportunities presented by a two-pronged approach to oral history: using testimony as evidence about historical experience in the past and as evidence about historical memory – both collective and individual – in the present.

A New Stereocontrolled Total Synthesis of the Mast Cell inhibitory Alkaloid, (+)-Monanchorin, via the Wittig Reaction of a Stabilized Ylide with a Cyclic Guanidine Hemiaminal

Abstract Image

An asymmetric total synthesis of the mast cell inhibitor (+)-monanchorin is reported in which a Sharpless AD on 11 and a cyclic sulfate ring opening with an azide feature as key steps. After further manipulation, a novel guanidine-controlled ester reduction provided the guanidine-hemiaminal 25 which underwent Wittig olefination to give 27. Hydrogenation and a second guanidine-controlled reduction of the ester in 28, to obtain aldehyde 29, then set up a trifluoroacetic acid mediated cyclization to give (+)-monanchorin TFA salt.

Reactions of enantiopure cyclic diols with sulfuryl chloride

Monocyclic allylic cis-1,2-diols reacted with sulfuryl chloride at 0 °C in a regio- and stereo-selective manner to give 2-chloro-1-sulfochloridates, which were hydrolysed to yield the corresponding trans-1,2-chlorohydrins. At −78 °C, with very slow addition of sulfuryl chloride, cyclic sulfates were formed in good yields, proved to be very reactive with nucleophiles and rapidly decomposed on attempted storage. Reaction of a cyclic sulfate with sodium azide yielded a trans-azidohydrin without evidence of allylic rearrangement occurring. An enantiopure bicyclic cis-1,2-diol reacted with sulfuryl chloride to give, exclusively, a trans-1,2-dichloride enantiomer with retention of configuration at the benzylic centre and inversion at the non-benzylic centre; a mechanism is presented to rationalise the observation.

System level DSP synthesis using voltage overscaling, unequal error protection & adaptive quality tuning

In this paper, we propose a system level design approach considering voltage over-scaling (VOS) that achieves error resiliency using unequal error protection of different computation elements, while incurring minor quality degradation. Depending on user specifications and severity of process variations/channel noise, the degree of VOS in each block of the system is adaptively tuned to ensure minimum system power while providing "just-the-right" amount of quality and robustness. This is achieved, by taking into consideration system level interactions and ensuring that under any change of operating conditions only the "lesscrucial" computations, that contribute less to block/system output quality, are affected. The design methodology applied to a DCT/IDCT system shows large power benefits (up to 69%) at reasonable image quality while tolerating errors induced by varying operating conditions (VOS, process variations, channel noise). Interestingly, the proposed IDCT scheme conceals channel noise at scaled voltages. ©2009 IEEE.

The barriers & solutions to providing good quality palliative care in dementia in the GP practice

BACKGROUND: Dementia is a significant worldwide health issue, however, it is often insidious in onset and difficult to diagnose, therefore GPs have expressed a limited confidence in their diagnostic skills, extending into their prognostication of the disease. As a result diagnosing the terminal phase of dementia has been identified as a significant challenge to delivering effective palliative care. Therefore, identifying the challenges faced by the GPs in this field will help to guide their training and support, and as a result could assist in the provision of sustained and effective palliative care for their dementia patients.

Conductivity/activation energy relationships for cement-based materials undergoing cyclic thermal excursions

The electrical conductivity of a range of concrete mixes, with and without supplementary cementitious materials (SCM), is studied through multiple cycles of heating and cooling over the extended temperature range −30/+70 °C. When presented in an Arrhenius format, the experimental results display hysteresis effects at the low-temperature end of the thermal cycle and, in those concretes containing supplementary cementitious materials at higher water/binder ratios, hysteresis effects were evident over the entire temperature range becoming more discernible with increasing number of thermal cycles. The depression in both the freezing and thawing point could be clearly identified and was used to estimate pore-neck and pore-cavity radii. A simplified approach is presented to evaluate the volumetric ratio of frozen pore water in terms of conductivity measurements. The results also show that the conductivity and activation energy of the concrete specimens were related to the water/binder ratio, type of SCM, physical state of the pore water and the thermal cycling regime.