Multidimensional Imaging of Density Driven Convection in a Porous Medium

Carbon dioxide (CO2) sequestration is a climate change mitigation technique which relies on residual and solubility trapping in injection locations with saline aquifers. The dissolution of CO2 into resident brines results in density-driven convection which further enhances the geological trapping potential. We report on the use of an analogue fluid pair to investigate density-driven convection in 3D in an unconsolidated bead pack. X-ray computed tomography (CT) is used to image density-driven convection in the opaque porous medium non-invasively. Two studies have been conducted that differ by the Rayleigh number (Ra) of the system, which in this study is changed by altering the maximum density difference of the fluid pair. We observe the same general mixing pattern in both studies. Initially, many high density fingers move downward through the bead pack and as time progresses these coalesce and form larger dominate flow paths. However, we also observe that a higher Rayleigh number leads to the denser plume moving faster towards the bottom of the system. Due to the finite size of the system, this in turn leads to early convective shut-down

Managing careers and managing fairness : an organisational justice theory perspective on employee evaluations of, and reactions to, organisational career management practices

This thesis presents the results of a multi-method investigation of employee perceptions of fairness in relation to their career management experiences. Organisational justice theory (OJT) was developed as a theoretical framework and data were gathered via 325 quantitative questionnaires, 20 semi-structured interviews and the analysis of a variety of company documents and materials. The results of the questionnaire survey provided strong support for the salience of employee perceptions of justice in regard to their evaluations of organisational career management (OCM) practices, with statistical support emerging for both an agent-systems and interaction model of organisational justice. The qualitative semi-structured interviews provided more detailed analysis of how fairness was experienced in practice, and confirmed the importance of the OJT constructs of fairness within this career management context. Fairness themes to emerge from this analysis included, equity, needs, voice, bias suppression, consistency, ethicality, respect and feedback drawing on many of the central tenants of distributive, procedural, interpersonal and information justice. For the career management literature there is empirical confirmation of a new theoretical framework for understanding employee evaluations of, and reactions to, OCM practices. For the justice literatures a new contextual domain is explored and confirmed, thus extending further the influence and applicability of the theory. For practitioners a new framework for developing, delivering and evaluating their own OCM policies and systems is presented

The role of line managers in employee career management:an attachment theory perspective

Line managers increasingly play a key role in organizational career development systems, yet few studies have examined the nature of this role or its implications for employee career attitudes and behaviors. In two studies, we used attachment theory to explore this issue. In Study 1, in-depth interviews (N = 20) showed that employees viewed career management as a relational process in which line managers are expected to act as ‘caregiver’ to support individualized career development. Study 2 was a large-scale international survey (N = 891). Participants scoring higher on attachment avoidance in their line manager relationships reported more negative perceptions of career growth opportunities, lower participation in organizational career development activities and higher turnover intentions. Trust in the organization partially mediated the relationship. Theoretical and practical implications for HRM are discussed

Services just for men? Insights from a national study of the well men services pilots.

Men continue to have a lower life expectancy in most countries compared to women. Explanations of this gendered health inequality tend to focus on male risk taking, unhealthy lifestyle choices and resistance to seeking help from health services. In the period 2005-2008 the Scottish Government funded a nationwide community health promotion programme aimed at improving men's health, called Well Men Service Pilots (henceforth WMS)

Multidimensional observations of dissolution-driven convection in simple porous media using X-ray CT scanning

We present an experimental study of dissolution-driven convection in a three-dimensional porous medium formed from a dense random packing of glass beads. Measurements are conducted using the model fluid system MEG/water in the regime of Rayleigh numbers, Ra=2000−5000. X-ray computed tomography is applied to image the spatial and temporal evolution of the solute plume non-invasively. The tomograms are used to compute macroscopic quantities including the rate of dissolution and horizontally averaged concentration profiles, and enable the visualisation of the flow patterns that arise upon mixing at a spatial resolution of about (2×2×2)mm3. The latter highlights that under this Ra regime convection becomes truly three-dimensional with the emergence of characteristic patterns that closely resemble the dynamical flow structures produced by high-resolution numerical simulations reported in the literature. We observe that the mixing process evolves systematically through three stages, starting from pure diffusion, followed by convection-dominated and shutdown. A modified diffusion equation is applied to model the convective process with an onset time of convection that compares favourably with the literature data and an effective diffusion coefficient that is almost two orders of magnitude larger than the molecular diffusivity of the solute. The comparison of the experimental observations of convective mixing against their numerical counterparts of the purely diffusive scenario enables the estimation of a non-dimensional convective mass flux in terms of the Sherwood number, Sh=0.025Ra. We observe that the latter scales linearly with Ra, in agreement with both experimental and numerical studies on thermal convection over the same Ra regime

“Men Behaving Badly”: Patriarchy, Public Policy and Health Inequalities

Gender is under-represented in the literature on health inequalities and social determinants of health; the latter are in turn under-represented in the literature on gender in general and on men and masculinities in particular. Furthermore, research and policy on gender and health frequently individualise issues of inequality, neglecting structural and systemic root causes of differential rates and experiences of morbidity and mortality. This article highlights the patriarchal social structures, attitudes and practices that, we argue, are common antecedents of these inequalities and suggests ways in which research and public policy can begin to address them. Patriarchy and hegemonic masculinity must be challenged as part of a wider set of social structural determinants of health