Investigating the effects of particle shape on normal compression and overconsolidation using DEM

Discrete element modelling of normal compression has been simulated on a sample of breakable two-ball clumps and compared to that of spheres. In both cases the size effect on strength is assumed to be that of real silica sand. The slopes of the normal compression lines are compared and found to be consistent with the proposed equation of the normal compression line. The values of the coefficient of earth pressure at rest K0,nc are also compared and related to the critical state fiction angles for the two materials. The breakable samples have then been unloaded to establish the stress ratios on unloading. At low overconsolidation ratios the values of K0 follow a well-established empirical relationship and realistic Poisson ratios are observed. On progressive unloading both samples head towards passive failure, and the values of the critical state lines in extension in q–p' space are found to be consistent with the critical state angles deduced from the values of K0 during normal compression. The paper highlights the important role of particle shape in governing the stress ratio during both normal compression and subsequent overconsolidation

Realizing autonomy in responsive relationships

The goal of this article is to augment the ethical discussion among nurses with the findings from empirical research on autonomy of older adults with type 2 diabetes mellitus. There are many factors influencing autonomy. These include: health conditions, treatment, knowledge, experience and skills, personal approach as well as familial patterns, type of relationship, life history and social context. Fifteen older adults with type 2 diabetes mellitus were interviewed in a nurse-led diabetes clinic. These participants perceive three processes which support autonomy in responsive relationships: preserving patterns of concern and interaction, nurturing collaborative responsibilities and being closely engaged in trustful and helpful family relations. People with diabetes realize autonomy in various responsive relationships in their unique life context. Next, we performed a literature review of care ethics and caring in nursing with regard to relational autonomy. We classified the literature in five strands of care: attitude-oriented, dialogue-oriented, activity-oriented, relationship-oriented and life-oriented. According to our respondents, autonomy in responsive relationships is fostered when patient, nurses, professionals of the health team and family members carry out care activities supported by a relational attitude of care. They can best realize autonomy in relationships with others when several essential aspects of care and caring are present in their lives. Therefore, we advocate a comprehensive approach to care and caring

The Dynamic Response of Etnean Sand and the Effect of Its Impingement on Ti-6Al-4 V Alloy

Quasi static and dynamic experiments were conducted to characterise the mechanical response of Etnean volcanic sand. Stress and strain histories were measured in near-uniaxial strain and near-uniaxial stress conditions at strain rates ranging between 5·10 −4 and 1.5·10 3 s −1 using bespoke experimental setups. The effects of the lateral confinement and initial consolidation state were assessed. Etnean volcanic sand exhibited a noticeable strain rate dependent behaviour when characterised in its loose consolidation state but not when densely packed before loading. The effect of volcanic particles impingement on Ti-6Al-4 V alloy was assessed by conducting dynamic experiments at different incident angles using targets of different geometry. The texture of thus eroded surfaces was analyzed by means of non-contact 3D-profilometry. The surface analysis provided insights on the erosion mechanisms and quantitative data on the roughness increment caused by the collision and rubbing with volcanic sand

Effect of Particle Morphology, Compaction, and Confinement on the High Strain Rate Behavior of Sand

The effect of grain shape, size distribution, intergranular friction, confinement, and initial compaction state on the high strain rate compressive mechanical response of sand is quantified using Long Split Hopkinson Pressure Bar (LSHPB) experiments, generating up to 1.1 ms long load pulses. This allowed the dynamic characterisation of different types of sand until full compaction (lowest initial void ratio) at different strain rates. The effect of the grain morphology and size on the dynamic compressive mechanical response of sand is assessed by conducting experiments on three types of sand: Ottawa Sand with quasi-spherical grains, Euroquartz Siligran with subangular grains and Q-Rok with polyhedral grain shape are considered in this study. The adoption of rigid (Ti64) and deformable (Latex) sand containers allowed for quasi-uniaxial strain and quasi-uniaxial stress conditions to be achieved respectively. Additionally, the effect of intergranular friction was studied, for the first time in literature, by employing polymer coated Euroquartz sand. Appropriate procedures for the preparation of samples at different representative initial consolidation states are utilized to achieve realistic range of naturally occurring formations of granular assembly from loose to dense state. The results identify material and confining sample state parameters which have significant effect on the mechanical response of sand at high strain rates and their interdependency for fut ure integration into rate dependent constitutive models

How do surgeons experience and cope with the death and dying of their patients? A qualitative study in the context of life-limiting illnesses

BackgroundThe present qualitative study explores surgeons' experiences and coping mechanisms with the death of their patients in the context of life-limiting illnesses.MethodsNine Australian surgeons participated in in-depth interviews. Thematic analysis of the interview transcriptions allowed for identification of themes and subthemes. Methodological trustworthiness and rigor were preserved at all stages of the research process.ResultsThe essence of surgical practice, comprising participants' descriptions of their identity as surgeons, influenced their experiences and coping mechanisms when dealing with death and dying. The following subthemes were identified: distancing from patients, wanting to fix problems, doing in terms of operating on a patient, prominence of the surgeon's personal ability, and high personal responsibility for patient outcomes. Giving hope and having a mixed surgical practice were some of the coping mechanisms described by participants.DiscussionDeath and dying are a part of surgical practice, and surgeons face challenges as they care for dying patients. Although participants stated that they felt less affected by dealing with patients dying of life-limiting illnesses than by unexpected deaths, their descriptions of their encounters, reactions, and behaviors, as well as their use of language, suggest that these deaths have a lasting impact. Potential areas for improvement of surgical practice and approaches to teaching about death and dying in surgery are addressed. Furthermore, the results of this study suggest the need to expand research in this area.Sofia C. Zambrano, Anna Chur-Hansen, Gregory B. Crawfor