A Finite Element approach to understanding constitutive elasto-plastic, visco-plastic behaviour in lead free micro-electronic BGA structures

This work investigates the non-linear elasto-plastic and visco-plastic behaviour of lead free solder material and soldered joints. Specifically, Finite Element (FE) tools were used to better understand the deformations within Ball Grid Array solder joints (BGA), and numerical and analytical methods were developed to quantify the identified constituent deformations. FE material models were based on the same empirical constitutive models (elastic, plastic and creep) used in analytical calculations. The current work recognises the large number of factors influencing material behaviour which has led to a wide range of published material properties for near eutectic SnAgCu alloys. The work discovered that the deformation within the BGA was more complex than is generally assumed in the literature. It was shown that shear deformation of the solder ball could account for less than 5% of total measured displacement in BGA samples. Shear displacement and rotation of the solder balls relative to the substrate are sensitive to the substrate orthotropic properties and substrate geometry (relative to solder volume and array pattern). The FE modelling was used to derive orthotropic FR4 properties independently using published data. An elastic modulus for Sn3.8Ag0.7Cu was measured using homologous temperatures below 0.3. Suggested values of Abaqus-specific creep parameters m and f (not found in literature) for Sn3.8Ag0.7Cu have been validated with published data. Basic verification against simple analytical calculations has given a better understanding of the components of overall specimen displacement that is normally missing from empirical validation alone. A combined approach of numerical and analytical modelling of BGAs, and mechanical tests, is recommended to harmonise published work, exploit new material data and for more informed analysis of new configurationsEPSRC-funded PhD studentshi

Envisat - taking the measure of North Atlantic storms

Envisat carries a number of sensors able to provide quantitative information on raining clouds: AATSR delivers information on cloud microphysics (particle size, temperature etc.), MWR-2 gives columnar totals for liquid and vapour forms of water, and RA-2 yields rain rate and wind speed. This paper examines the complementarity of these sensors, with a focussed study on significant rain events in the N. Atlantic, covering both coherent large storms and fronts with smaller scale structure. The difference in liquid water estimates from the infra-red and passive systems appears to be related to the temperature and sizes of drops being detected

Holding On/Letting Go: Situating Trauma and Memory in Theatrical Spaces

In this essay, I review my development as a playwright in the MFA Dramatic Writing program and examine the shifting, overlapping goals of playwright-as-educator and playwright-as-entertainer. In Part One, I position my academic exploration of trauma in relation to ethics in journalism, embodied knowledge, and intersectional feminism and outline my creative experiments in staging trauma through the process of witnessing, retelling, and abstraction. In Part Two, I detail the artistic and personal roots of my dissertation play, The Great Maverick Adventure of 2007, and the structural and dramaturgical tools I employed to rebuild a sense of play and theatricality in my work

Identification of group B respiratory syncytial viruses that lack the 60-nucleotide duplication after six consecutive epidemics of total BA dominance at coastal Kenya

Respiratory syncytial virus BA genotype has reportedly replaced other group B genotypes worldwide. We report the observation of three group B viruses, all identical in G sequence but lacking the BA duplication, at a coastal district hospital in Kenya in early 2012. This follows a period of six consecutive respiratory syncytial virus (RSV) epidemics with 100% BA dominance among group B isolates. The new strains appear only distantly related to BA variants and to previously circulating SAB1 viruses last seen in the district in 2005, suggesting that they were circulating elsewhere undetected. These results are of relevance to an understanding of RSV persistence

Is practice placement capacity helping the NHS to recruit healthcare professionals?

YesPractice placements are a fundamental aspect of preparing students for working in the NHS and will influence where, and in what specialities, students work. Additionally, NHS leaders now consider the issues of recruitment and retention of NHS staff to be as serious as concerns over funding. NHS Providers have outlined the issues although there appears to be little, or no, consideration in terms of plans required for the most immediate future workforce. It is hypothesised that there is link between student healthcare placement capacity and workforce gaps. The policy of increasing training places and of funding practice placements may have a positive effect on practice placement provision and if so contribute to increasing the NHS workforce, but without further detail this impact remains unknown. Along with most aspects of service delivery, planning practice placements using the best available evidence will ensure that the impact on service delivery is minimised while maximising the experience for the next generation of NHS employees

Gender and capacity building : a multi-layered study of empowerment

This study shifts the focus from building individual capacities to understanding the relational acts through which empowerment and education acquire their value and meaning. Conceptually, the paper employs social cognitive theory to explore the interplay between social learning, relational agency, and culture. This interplay builds the foundation for the development of an empowerment model of capacity building that proposes an interlinked system of community capacity and empowerment dimensions. The model is explored in the context of the Education for All project in the High Atlas Mountains of Morocco. The research combines participant observation, qualitative interviews and visual methods to provide rich insights to situated knowledges of learning and empowerment. Findings reveal that the meaning of education equates to the capacity to aspire to a different life. This problematizes the way gender and gender relations are understood in the rural Berber villages. The girls’ education unsettles the repeating cycle of female educational deprivation, and leads them to become role models within their communities. This instills the image of educated women in community consciousness, leading to an incipient change in perceptions of what girls and women can be and do

What not to write:an intervention in written communication skills for accounting students

Abstract: This study considers the evidence that many accounting students struggle to write accurately and appropriately, which in turn has negative implications on their wider employability. Using an intervention approach, initiatives were taken to address this problem for first year accounting undergraduates at the University of Portsmouth. The results indicate that some improvements are possible and students' self-awareness of the issue was raised, but that in order to sustain any improvements an increased focus on the teaching of writing skills would be required. This may have resource implications but the potential benefits to students in the wider realm could be significant. The initiative is targeted specifically at the enhancement of employability and, although based around extracts from the accounting literature, could readily be transferred to other subject areas. 126 word

Harbour porpoises (Phocoena phocoena) and minke whales (Balaenoptera acutorostrata) observed during land-based surveys in The Minch, north-west Scotland

Peer reviewedPublisher PD