62 research outputs found

    Auxetic response of additive manufactured cubic chiral lattices at large plastic strains

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    Auxetic lattices exhibit a negative Poisson’s ratio and excellent energy absorption capability. Here, we investigate the compressive performance of auxetic cubic chiral structures. By utilising finite element analysis (FEA) verified by interrupted mechanical testing and x-ray computed tomography, the auxeticity and failure mechanisms at the large strain deformation have been evaluated. The FEA results show that the initial elastic–plastic response agrees with the prediction of the classic scaling laws of bending-dominated lattices. At increasing plastic deformation, the energy absorption and auxeticity are dependent on relative density, i.e., the slenderness ratio, of the constitutive struts. In the plastic regime, the auxeticity decreases with relative density. Ductile fracture precedes densification in relative densities above 1.2%, thus dictating a new scaling law for the variation of the maximum energy absorbed with density. The numerical model predicts the scaling of mechanical properties, fracture strains, and energy absorption of the constitutive unit cell and finite-sized specimens in the relative density ranging from 0.3% to 6.5%. However, to accurately model the failure mechanism, geometrical imperfections should be included. The scaling laws derived from this work may aid the design of next generation auxetic lattices with tailored mechanical properties

    Oxidation induced mechanisms during directed energy deposition additive manufactured titanium alloy builds

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    To prevent oxygen contamination, additive manufacturing (AM) techniques normally operate in an inert gas chamber (GC). An alternative method, useful for large builds and components repair, is the application of localised shielding gas (LSG). The effect of oxygen contamination on Ti6242 during directed energy deposition (DED) AM using an inert GC compared to LSG was investigated by in situ synchrotron x-ray experiments. When processing in LSG mode, the amount of oxygen absorbed from the atmosphere was sufficient to reverse the Marangoni flow leading to an alteration of the molten pool geometry and strongly influencing defect formation. Microstructural analysis reveals that, at high oxygen levels, the commonly developed α' martensitic microstructure was completely suppressed, forming precipitation of a tetra modal microstructure of α phase consisting of globular, primary and secondary lamellae (in colonies) and basketweave structure. These results help elucidate the influence of oxygen contamination in additively manufactured Ti alloys, potentially enabling improved industrial practices for AM of titanium alloy

    Scientific output on transsexuality in the Spanish biomedical literature: Bibliometric and content analysis (1973-2011)

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    Objetivo: Explorar la evolución del conocimiento científico sobre transexualidad durante los últimos 40 años, a través de un análisis bibliométrico y de contenido de la producción de la literatura biomédica española sobre la transexualidad entre los años 1973 y 2011. Método: Descriptivo y transversal. Universo: artículos biomédicos españoles sobre transexualidad publicados entre 1973 y 2011. Fuente: ÍndiceMédico Español e ISOC-Ciencias Sociales y Humanidades. Análisis: bibliométrico y de contenido de las publicaciones biomédicas. Resultados: 65 artículos biomédicos analizados. Entre 1973 y 1984, en España, el conocimiento sobre transexualidad se produce y circula en revistas médicas. En 1996 se inicia una década de gran productividad, y en los años siguientes el número de revistas que publican sobre transexualidad se multiplica. Hasta 2006, año de mayor productividad biomédica, los discursos biomédicos reproducen representaciones de la transexualidad ancladas en el determinismo biológico. En el período 2008-2011, los y las profesionales incorporan teorías feministas y perspectivas sociales en sus discursos. Conclusiones: En el último cuarto del siglo xx, el discurso médico dominante ha considerado las manifestaciones de las personas transexuales desde una perspectiva biologicista que concibe la transexualidad como un error de correspondencia sexo/género. En los últimos años, la aparición de nuevas categorías de identidad y la reflexión desde posturas no esencialistas y normativas del género favorece la gestión clínica de la transexualidad.Objective: To explore the scientific output on transsexuality in the Spanish biomedical literature between 1973 and 2011, through bibliometric and content analyses. Methods: We carried out a descriptive, cross-sectional study of Spanish biomedical articles on transsexuality published between 1973 and 2011. The data sources consisted of Índice Médico Español and ISOC-Ciencias Sociales y Humanidades. Bibliometric and content analyses were performed. Results: A total of 65 papers were analyzed. Knowledge on transsexuality in Spain began to appear in medical journals between 1973 and 1984. A decade of intense productivity began in 1996 and the number of journals publishing articles on transsexuality multiplied in the following years. Until 2006, the year with the most biomedical productivity, biomedical discourses reproduced representations of transsexuality anchored in biological determinism. From 2008-2011, professionals writing on the topic incorporated feminist theories and social perspectives in their discourses. Conclusions: In the last quarter of the twentieth century, the dominant medical discourse considered manifestations of transsexual people from a biologist perspective that conceives transsexuality as a configuration mismatch between sex and gender. The emergence of new identity categories and medical reflection from non-essentialist and non-normative gender perspectives has improved the clinical management of transsexuality

    Polyamorous Families – Parenting Practice, Stigma and Social Regulation

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    As a response to the greater visibility of alternative relationship and family forms, polyamory (i.e. the practice of consensual multi-partner relationships) has recently moved to the centre of public media attention. Questions of polyamory have emerged as a major concern within law, social policy, family sociology, gender and sexuality studies. Yet certain core issues have remained underexplored. This includes the distinctive nature of polyamorous intimacy, the structure of poly household formations and the dynamics of care work within poly families. In particular, poly parenting has been subject to tabooisation and scandalisation. Governing bodies, the judiciary and educational institutions have remained largely ignorant of polyamorous relationships. Research documents the exclusions of poly families (and individuals) from access to legal provisions and protections and their common discrimination in the courts, namely in custody cases. It further highlights the discrimination of polyidentified adolescents in school and college settings and the predicament that poly families face when interacting with public institutions (including schools and kindergardens). Insights into parenting practices and the organisation of childcare is vital for understanding the transformative potential of polyamorous ways of relating. It is also important for challenging the common demonisation and stigmatisation of polyamory within conservative family politics that perceives polyamory exclusively from a harm perspective. This paper will review and critically analyse existing research on poly parenting focussing on three dimensions: (a) parenting practices, (b) social and legal discrimination, and (c) parental response to stigmatisation. The paper argues for a stronger incorporation of queer perspectives within the guiding frameworks of research into parenting in consensually non-monogamous and polyamorous relationships to highlight the transformative potential of the ‘queer bonds’ that sustain many of these practices

    Psychotherapy

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    In this chapter we provide an overview of psychotherapeutic and counselling practice with non-binary clients. After a brief introduction to non-binary clients and the general mental health of this client group, we explore the ways in which the major psychotherapeutic approaches (humanistic, psychodynamic, and cognitive-behavioural) conceptualise gender identity and expression, and the potential tensions and possibilities of these conceptualisations in relation to non-binary experience. We also offer ideas and practices from the existential and systemic therapeutic approaches, which often utilise less binary conceptualisations of gender

    Social models of disability and sexual distress

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    In this chapter we suggest that there is much to be gained from bringing social models of disability into dialogue with current understandings of sexual distress. First, sexologists and sexual health practitioners could benefit hugely from applying the shift from medical to social thinking about disability to the arenas of sexual ‘disorders’ or ‘dysfunctions’. Secondly, it is fruitful for those studying and working with disability to extend social models to include considerations of sex and sexuality, as in some of the more recent, intersectional revisions of these models. In order to explore the potential of such a dialogue we devote the first half of this chapter to examining how prevailing norms of sex and sexuality position many of us as mentally disordered or dysfunctional, and could therefore be said to actively disorder or disable people in a manner akin to the way in which certain material features and social norms disable certain bodies and sensory and cognitive experiences. We consider how features of the shift from medical to social models of disability can be applied in this area, to the benefit of those who are struggling with sexual distress and in ways which enhance understandings of sex and sexuality more widely. By ‘sexual distress’ we mean mental distress which occurs specifically around sex, for example feeling anxious about sexual situations or ashamed of sexual desires. Following this, in the second half of the chapter, we examine the ways in which medicalised understandings of both sex and disability constrain and restrict the sexual experience and expression of disabled people. We draw out the potential benefits of applying social models of disability to this area, building particularly on recent intersectional work to enable a fuller understanding of the ways in which sexuality, disability, and other aspects of identity and experience combine. In the concluding section of the chapter we weave these strands together to suggest how social, critical and intersectional understandings of sexuality and disability could inform thinking and practice around both these areas
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