A Note on the Energy Release Rate in Quasi-Static Elastic Crack Propagation

This paper considers analytical issues associated with the notion of the energy release rate in quasi-static elastic crack propagation

On shock waves in solids

This paper describes some recent theoretical results pertaining to the experimentally-observed relation between the speed of a shock wave in a solid and the particle velocity immediately behind the shock. The new feature in the present analysis is the assumption that compressive strains are limited by a materially-determined critical value, and that the internal energy density characterizing the material is unbounded as this critical strain is approached. It is shown that, with this assumption in force, the theoretical relation between shock speed and particle velocity is consistent with many experimental observations in the sense that it is asymptotically linear for strong shocks of the kind often arising in the laboratory

CAPITAL FOR THE AGRICULTURE OF THE FUTURE

Agricultural Finance,

Part 1: Supporting the Reduction of Suicide in the General Population of Wales via the use of Structured Professional Judgement; Part 2: Identifying the Factors Moderating Suicidal Thoughts and Suicide Attempts During the COVID-19 Pandemic.

Part 1: Early identification of individuals at risk of suicide represents a crucial component of effective suicide prevention. However, many of the current suicide risk assessment procedures are limited in their ability to identify and prevent future suicide attempts. This thesis aimed to investigate whether the structured professional judgement approach was an effective method of suicide risk assessment within an accident and emergency department. Chapter 1 outlined the major challenges facing the field of suicide risk assessment and introduced the structured professional judgement approach to risk assessment. Chapter 2 reviewed the various methods used to assess the risk of suicide within accident and emergency services, evaluated the efficacy of the structured professional judgement approach and outlined the new structured professional judgement scheme, the Risk of Suicide Protocol, that was investigated in this thesis. Chapter 3 compared the Risk of Suicide Protocol and assessment as usual in their ability to identify future suicide attempts in 107 participants referred for a suicide risk assessment with the accident and emergency-based Psychiatric Liaison Team. Chapter 3 also evaluated the inter-rater reliability of the Risk of Suicide Protocol, with two independent assessors completing assessments on the same 12 patients. Chapter 7 reviewed the research relating to the RoSP and discussed the wider meaning and clinical implications of the findings. The findings demonstrated that risk judgements made using the Risk of Suicide Protocol were significantly better at identifying future suicide attempts compared to assessment as usual. Additionally, the risk judgements made using the Risk of Suicide Protocol demonstrated excellent inter-rater reliability. These results indicate that the Risk of Suicide Protocol is a valid and reliable assessment for the structured clinical evaluation of suicide risk within an accident and emergency department. Overall, this thesis demonstrates that the Risk of Suicide Protocol represents a valuable method for the evaluation of suicide risk and may offer an important solution to some of the challenges facing the field of suicide risk assessment. Part 2: The COVID-19 pandemic resulted in a wide range of difficulties for populations across the world, with research indicating that the pandemic had negatively impacted population mental health. This thesis aimed to identify and understand the factors influencing suicidal thoughts and attempts during the COVID-19 pandemic. Chapters 1 and 4 reviewed how the COVID-19 pandemic affected population mental health and suicidality and explored the rationale for this research. Chapters 5 and 6 reported the results of an online survey administered to a large sample of adults (N > 13,000) living in Wales between the 18th of January 2021 to the 7th of March 2021. Chapter 5 aimed firstly, to identify the demographic groups most vulnerable to suicidal thoughts and attempts and secondly, to examine whether various pandemic related stressors (e.g., social isolation, food insecurity) were associated with suicidal thoughts and attempts. Chapter 6 investigated whether hope, social connectedness, resilience or pandemic acceptance could protect against the presence of suicidal thoughts during the COVID-19 pandemic. Chapter 7 reviewed the research and considered the wider implications of the findings. The findings from chapter 5 revealed that men, younger adults and socioeconomically deprived individuals were more likely to experience suicidal thoughts during the pandemic, with younger adults also more likely to attempt suicide. Chapter 5 also found that domestic abuse, food insecurity, difficulty accessing healthcare, social isolation, relationship problems, financial problems and being made redundant were the pandemic related stressors most strongly related to suicidal thoughts and attempts. Chapter 6 found that hope, resilience and pandemic acceptance all protected against suicidal thoughts during the pandemic, with higher levels of hope, resilience and pandemic acceptance weakening the relationship between pandemic stress and suicidal thoughts. Overall, this thesis has enhanced our understanding of the factors influencing suicidal thoughts and attempts during the COVID-19 pandemic. The findings provide valuable insights that can be used to inform outreach and support structures in their efforts to prevent suicide

Eli Sternberg Memoriam

Eli Sternberg, perhaps the best known scholar in the field of elasticity during most of the past half-century, died suddenly in Pasadena, California, on October 8, 1988, shortly before his seventy-first birthday

An Energy Estimate for the Biharmonic Equation and its Application to Saint-Venant's Principle in Plane Elastostatics

A new energy estimate is given for a boundary value problem for the biharmonic equation. The result is applied to the estimation of stresses in a plane elasticity problem

A note on anti-plane shear for compressible materials in finite elastostatics

This note gives a necessary and sufficient condition that a compressible, isotropic elastic material should admit non-trivial states of finite anti-plane shear

A bifurcation study of a dynamic model of a nose landing gear mechanism subjected to external disturbances

This paper presents a new modelling approach for the analysis of landing gear mechanisms. By replacing the mechanism's rotational joints with equivalent high-stiffness elastic joints, numerical continuation methods can be applied directly to dynamic models of landing gear mechanisms. The effects of using elastic joints are considered through two applications --| an overcentre mechanism, and a nose landing gear mechanism. In both cases, selecting a suffcient stiffness for the elastic joint is shown to provide accurate contiuation results. The advantages of this new modelling approach are then demonstrated by considering the unlocking of a nose landing gear with a single uplock/downlock mechanism, when subjected to different orientations and magnitudes of gravitational loading. The unlocking process is shown to be qualitatively insensitive to changes in both load angle and load magnitude, ratifying the robustness of a previously- proposed control methodology for unlocking a nose landing gear with a single uplock/downlock mechanism

Becoming Prospective Medicine Students. A Case Study of Access to Medicine Students’ Descriptions of Their Experiences of a Further Education Course in the UK as Determined Through Narrative Enquiry and Poststructuralist Discourse Analysis

‘Becoming prospective medicine students' is about how ‘Access to medicine’ students at a college of Further Education (FE) in England describe their experiences of the course and how they become positioned through discourses as they prepare to progress from an ‘Access’ course to medical schools. The research explores students’ descriptions of their experiences of an ‘Access to medicine’ course and discusses whether the course is promoting equity and inclusion for socially and educationally disadvantaged students. The thesis contributes to the literature on widening participation in Higher Education (HE), mainly widening participation in medicine. Only the second educational research report into an ‘Access to medicine’ course, the thesis extends understandings of the same course at the same FE college eighteen years later. The novel contribution is that this is the first report to investigate the students' experiences of an ‘Access to medicine’ course using Foucauldian discourse analysis. I argue that the dominant ‘learning market’ approach to FE undermines the aims of ‘Access to HE’ courses which are designed to widen participation in HE and promote equity and inclusion of students. Policymakers and OFSTED need to wake up and recognise that dominating discourses based around the hard work ethic and vocational biases towards the purposes of FE promote capitalism and reproduce the social and educational inequalities which consecutive governments since 1979 have claimed to aim to reduce. ‘Becoming prospective medicine students' offers an alternative to existing research into widening participation in medicine through reporting the students’ subjective experiences of an ‘Access to medicine’ course while exploring whether and how the course actually widens participation in medicine. It is hoped that ‘Becoming prospective medicine students’ will prove useful to anyone interested in students' experiences of FE courses, anyone questioning the political motives of policymakers and exposing them or anyone wondering what it is like to aspire to study medicine at university

Bifurcation study of a dynamic model of a landing gear mechanism

This paper presents a new modelling approach for the analysis of landing gear mecha- nisms. By replacing the mechanism's rotational joints with equivalent high-sti ness elas- tic joints, numerical continuation methods can be applied directly to dynamic models of landing gear mechanisms. The e ects of using elastic joints are considered through two applications | an overcentre mechanism, and a nose landing gear mechanism. In both cases, selecting a su cient sti ness for the elastic joint is shown to provide accurate con- tiuation results. The advantages of this new modelling approach are then demonstrated by considering the unlocking of a nose landing gear with a single uplock/downlock mechanism, when subjected to di erent orientations and magnitudes of gravitational loading. The un- locking process is shown to be qualitatively insensitive to changes in both load angle and load magnitude, ratifying the robustness of a previously-proposed control methodology for unlocking a nose landing gear with a single uplock/downlock mechanism