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

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

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

How to Understand Your Gender: A Practical Guide for Exploring Who You Are

This helpful guide presents ways we can all better understand gender, and how people can change and express their gender identity. Considering biological and cultural understandings of gender, gender expression, and relationships and sexuality, this is an excellent starting point for anybody thinking about what gender means to them

Psychotherapy

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

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

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

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% to6.5%. 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

The Relationship Between Use of Sexually Explicit Media and Sexual Risk Behavior in Men Who Have Sex with Men:Exploring the Mediating Effects of Sexual Self-Esteem and Condom Use Self-Efficacy

This study tests the following three hypotheses: 1) there is a direct association between consumption of sexually explicit media (SEM) depicting non-condom use and STI-related sexual risk behavior among men who have sex with men (MSM), 2) The association between SEM consumption and STI-related sexual risk behavior is mediated by men’s sexual self-esteem, and 3) the relationship between SEM consumption and sexual risk behavior is mediated by condom use self-efficacy. A cross-sectional, Internet-based survey on exposure to SEM and sexual behavior of 1,391 MSM in the USA was conducted in 2011. The results confirmed hypothesis 1 and 3 while hypothesis 2 was rejected. Accordingly, a significant association between the use of SEM picturing condom use and STI related sexual risk behavior among MSM was found. Likewise, we found that the association between the use of SEM and sexual risk behavior was mediated by condom use self-efficacy in an indirect path. However, SEM did not influence sexual risk behavior via sexual self-esteem. To promote STI prevention, the actors in SEM may be used as role models in managing condom use in sexual contexts