The effect of laser remelting on the surface chemistry of Ti6al4V components fabricated by selective laser melting

Surface remelting/skin scanning of components is generally performed during the selective laser melting (SLM) process to improve the surface quality of a part. However, the chemical effects of surface remelting are not well understood. In this study, cuboidal parts fabricated with and without laser remelting were characterised using scanning electron microscopy (SEM), surface profilometry and X-ray photoelectron spectrophotometry (XPS). The SEM images showed a low-amplitude undulating pattern was observed on both surfaces. The surface chemistries of the surface remelted/skin scanned (SK) and non-surface remelted/non-skin scanned (NSK) samples were observed to significantly differ in their elemental composition. The thickness of the surface oxide layer of the SK surface was double that of the NSK surface. Also, the contribution of the major alloying elements, including titanium and aluminium, on the surface oxide layer varied for both NSK and SK surfaces. The surface chemistry of the NSK and SK surface was significantly different to a conventionally forged (CF) Ti6Al4V surface. The rate of decrease of oxide with depth was in the order of CF > NSK > SK. Although surface remelting is useful in rendering improved surface quality, its impact on surface chemistry should be carefully considered

Functionalisation of Ti6Al4V components fabricated using selective laser melting with a bioactive compound

Surface modification of an implant with a biomolecule is used to improve its biocompatibility and to reduce post-implant complications. In this study, a novel approach has been used to functionalise phosphonic acid monolayers with a drug. Ti6Al4V components fabricated using selective laser melting (SLM) were functionalised with Paracetamol (a pharmaceutically relevant biomolecule) using phosphonic acid based self-assembled monolayers (SAMs). The attachment, stability of the monolayers on the SLM fabricated surface and functionalisation of SAMs with Paracetamol were studied using X-ray photoelectron spectroscopy (XPS) and surface wettability measurements. The obtained results confirmed that SAMs were stable on the Ti6Al4V surface for over four weeks and then began to desorb from the surface. The reaction used to functionalise the phosphonic acid monolayers with Paracetamol was noted to be successful. Thus, the proposed method has the potential to immobilise drugs/proteins to SAM coated surfaces and improve their biocompatibility and reduce post-implant complications

Domestic Violence and Health Care: Opening Pandora¿s Box ¿ Challenges and Dilemmas

In this article we take a critical stance toward the rational progressive narrative surrounding the integration of domestic violence within health care. Whilst changes in recent UK policy and practice have resulted in several tangible benefits, it is argued that there may be hidden dilemmas and challenges. We suggest that the medical model of care and its discursive practices position women as individually accountable for domestic violence-related symptoms and injuries. This may not only be ineffective in terms of service provision but could also have the potential to reduce the political significance of domestic violence as an issue of concern for all women. Furthermore, it is argued that the use of specific metaphors enables practitioners to distance themselves from interactions that may prove to be less comfortable and provide less than certain outcomes. Our analysis explores the possibilities for change that might currently be available. This would appear to involve a consideration of alternative discourses and the reformulation of power relations and subject positions in health care

Ultra high hole mobilities in a pure strained Ge quantum well

Hole mobilities at low and room temperature (RT) have been studied for a strained sGe/SiGe heterostructure using standard Van der Pauw resistivity and Hall effect measurements. The range of magnetic field and temperatures used were − 14 T 3 cm2/V s was determined for a sheet density (ps) 9.8 × 1010 cm-2 (by ME-MSA) and (3.9 ± 0.2) × 103 cm2/V s for a sheet density (ps) 5.9 × 1010 cm-2 (by BAMS)