922017 research outputs found
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Experimental and numerical investigations into electrochemical milling
No full textThis paper presents experimental and numerical investigations into electro-chemical (EC) milling of simple features such as slots and pockets. Preliminary experimental investigations into the machining of a slot enabled appropriate process parameters to be selected; these were then used to machine a simple square pocket and finally a pocket with a human-being shaped protrusion. These features were machined with tools having circular and square cross-sections. The pocket with the protrusion was machined with tool paths of zig–zag and contour-parallel type. The experimental results indicated that the machining accuracy depends upon, amongst other things, on the tool shape and process parameters. A boundary element of the EC machining process was used to predict the shape of the pockets and in most cases, the predicted shapes compared favourably with the actual machined features
Linking adaptation science to action to build food secure Pacific Island communities
No full textClimate change is a major threat to food security in Pacific Island countries, with declines in food production and increasing variability in food supplies already evident across the region. Such impacts have already led to observed consequences for human health, safety and economic prosperity. Enhancing the adaptive capacity of Pacific Island communities is one way to reduce vulnerability and is underpinned by the extent to which people can access, understand and use new knowledge to inform their decision-making processes. However, effective engagement of Pacific Island communities in climate adaption remains variable and is an ongoing and significant challenge. Here, we use a qualitative research approach to identify the impediments to engaging Pacific Island communities in the adaptations needed to safeguard food security. The main barriers include cultural differences between western science and cultural knowledge, a lack of trust among local communities and external scientists, inappropriate governance structures, and a lack of political and technical support. We identify the importance of adaptation science, local social networks, key actors (i.e., influential and trusted individuals), and relevant forms of knowledge exchange as being critical to overcoming these barriers. We also identify the importance of co-ordination with existing on-ground activities to effectively leverage, as opposed to duplicating, capacity
H εκπαίδευση στην κοινωνική εργασία την εποχή της κρίσης στην Ελλάδα: εκπαιδεύοντας το ανθρώπινο δυναμικό να καταπολεμήσει τις ανισότητες
No full textSince 2010, Greece has experienced an unprecedented economic and humanitarian crisis, which continues to have tremendous social impact. Austerity measures and policy cuts have included a dis-investment in social work and social care and more recently the abolition of one of the four national Social Work Departments providing qualifying social work education. In this context, this study addresses the following question: how does pre-qualifying social work education in Greece influence students’ ability to manage value tensions in relation to anti-oppressive practice? Using a case study methodology, the research was based in one Social Work Department (subsequently abolished). Data were collected through semi-structured interviews from social work students at two points in their professional education (n=32) and once from academic staff/placement supervisors (n=10). Data were analysed drawing on grounded theory techniques. In this paper only one particular dataset is considered in detail: the attitudes and experiences of final year students. The main findings indicate students’ narrow understandings and individualistic approaches towards oppression, reflecting an urgent need to redefine social work education and practice in Greece according to current social justice concerns. Specifically, social work education needs to give greater weight to a structural perspective on the dynamics of oppression
Value assessment and quantitative benefit-risk modelling of biosimilar infliximab for Crohn’s disease
No full textAim: Regulatory approval of biosimilars often depends on extrapolating evidence from one clinical indication to all of those of the originator biologic. We aimed to develop a quantitative benefit-risk analysis to assess whether the resulting increase in the uncertainty in the clinical performance of biosimilars (i.e. risk) may be countered by their lower pricing (benefit).Methods: A one-year decision-analytic model was developed for the biosimilar infliximab (Inflectra®) for Crohn’s disease. The perspective was that of the NHS in the UK and costs were valued to 2015/16. A hypothetical cohort of biologic-naïve patients with moderate-to-severe Crohn’s disease were simulated through the model. Immunogenicity to infliximab was a key modifier, influencing rates of non-response and infusion reactions. Net health benefit was estimated based on quality-adjusted life years (QALYs). A range of sensitivity analyses tested the robustness of the results and explored how the biosimilar price must respond to varying immunogenicity to remain the preferred option. Results: The base-case analysis predicted a positive incremental net health benefit of 0.04 (95% Central Range 0.00-0.09) favouring the biosimilar, based on 0.803 QALYs, and costs of £18,087 and £19,176 for biosimilar and originator, respectively. Two-way sensitivity analyses suggested that if 50% of patients developed antibodies, the value-based price of £410 per vial must be lower than that of the originator (£420), but remain higher than the actual market price (£378). Conclusions: The model supports the use of Inflecta® for Crohn’s disease in the UK, and provides a framework for the quantitative evaluation of biosimilars in the context of health technology assessment. Value-based pricing using this methodology could protect health systems from the potential risks of biosimilars where they are untested in the approved populations.<br/
Stability analysis for time-dependent nonlinear systems. An interval approach
No full textOne of the most important issues in control is determining the stability of a system. Since the 1960’s, Lyapunov-based methods have been developed to determine the stability of linear and nonlinear systems. However, when the system is nonlinear, time-dependent and uncertain, in a set-membership context, stability analysis is challenging and no reliable methods have been developed. This paper proposes an original set-membership based approach for establishing the stability of non-linear, uncertain, time-dependent systems. Two new concepts G-Stability (which is the stability of nonlinear time-dependent uncertain trajectories) and capture tubes (which is an invariant stability region for time-dependent systems) are introduced and illustrated for an autonomous, uncertain, robotic sailboat. Then, G-Stability is used to formulate and prove the safety for a set of capture tubes. This result is then used to analyse the safety of a squad of uncertain, robotic sailboat moving in their environment (no collision among the robots)
On the approximate zeroth and first order consistency in the presence of irregular boundaries in SPH obtained by the virtual boundary particle methods
No full textFitting the bill? (Dis)embodied disclosure of sexual identities in the workplace
No full textThe disclosure of lesbian, gay or bisexual identity is generally presented as a conscious act of leaving heterosexuality (Ragins, 2004). Such interpretation fails to take into account the dynamic processes involved in constructing non-heterosexual identities and to what degree such identities are embodied or disembodied. Supported by interview data among lesbian and gay employees in six British workplaces, this article explores how non-heterosexual identities become known in organisational settings by arguing that lesbians and gay men continue to collide with social expectations and stereotypical ideas of how sexual identities should be “worn” and performed. These both shape colleagues’ assumptions about their non-heterosexual identities and can expose lesbians and gay men to negative behaviour at work in highly gendered ways
On the use of Dynamic Thermal Line Ratings for Improving Operational Tripping Schemes
No full textThe increasing volume of renewable and intermittent generation that is being connected to power systems means that system operators need more advanced dynamic control tools to manage the increase in congestion and the resulting pressure on system constraints. Dynamic thermal line rating (DTLR) is the thermal rating of a transmission line that is calculated in real-time based on online measurements of the loading of the asset and local weather conditions. This dynamic rating will usually be greater than the static rating that is currently used, as the static rating is defined for the worst case scenario. Therefore, using the dynamic rating allows the thermal constraint on a line to be relaxed and the maximum loading increased. An Operational Tripping Scheme (OTS) is a type of System Integrity Protection Scheme (SIPS) that is used to relieve overloads on transmission lines during stressed system conditions by tripping pre-selected generation assets that are connected to the protected lines. . An OTS is used to increase power flow on overhead lines, without building new assets or compromising security, but doing so results in potential generation constraints and higher system risk. This paper presents the novel integration of DTLRs into an existing OTS in order to improve its performance by reducing the likelihood of unnecessary generation tripping due to overly conservative line ratings. This novel OTS affords the system economic benefits, by avoiding unnecessary tripping, and improves system security, by limiting the propagation of disturbed conditions and avoiding unnecessary tripping actions that could initiate dangerous cascading events that might lead to system blackouts. The new scheme is an example of a Wide Area Monitoring, Protection and Control (WAMPAC) application