Toward a better understanding of tool wear effect through a comparison between experiments and SPH numerical modelling of machining hard materials

The aim of this study is to improve the general understanding of tungsten carbide (WC–Co) tool wear under dry machining of the hard-to-cut titanium alloy Ti6Al4V. The chosen approach includes experimental and numerical tests. The experimental part is designed to identify wear mechanisms using cutting force measurements, scanning electron microscope observations and optical profilometer analysis. Machining tests were conducted in the orthogonal cutting framework and showed a strong evolution of the cutting forces and the chip profiles with tool wear. Then, a numerical method has been used in order to model the machining process with both new and worn tools. The use of smoothed particle hydrodynamics model (SPH model) as a numerical tool for a better understanding of the chip formation with worn tools is a key aspect of this work. The redicted chip morphology and the cutting force evolution with respect to the tool wear are qualitatively compared with experimental trends. The chip formation mechanisms during dry cutting process are shown to be quite dependent from the worn tool geometry. These mechanisms explain the high variation of the experimental and numerical feed force between new and worn tools

Community-based doulas for migrant and refugee women: a mixed-method systematic review and narrative synthesis.

BACKGROUND: Community-based doulas share the same cultural, linguistic, ethnic backgrounds or social experiences as the women they support. Community-based doulas may be able to bridge gaps for migrant and refugee women in maternity settings in high-income countries (HICs). The aim of this review was to explore key stakeholders' perceptions and experiences of community-based doula programmes for migrant and refugee women during labour and birth in HICs, and identify factors affecting implementation and sustainability of such programmes. METHODS: We conducted a mixed-method systematic review, searching MEDLINE, CINAHL, Web of Science, Embase and grey literature databases from inception to 20th January 2022. Primary qualitative, quantitative and mixed-methods studies focusing on stakeholders' perspectives and experiences of community-based doula support during labour and birth in any HIC and any type of health facility were eligible for inclusion. We used a narrative synthesis approach to analysis and GRADE-CERQual approach to assess confidence in qualitative findings. RESULTS: Twelve included studies were from four countries (USA, Sweden, England and Australia). There were 26 findings categorised under three domains: (1) community-based doulas' role in increasing capacity of existing maternity services; (2) impact on migrant and refugee women's experiences and health; and (3) factors associated with implementing and sustaining a community-based doula programme. CONCLUSION: Community-based doula programmes can provide culturally-responsive care to migrant and refugee women in HICs. These findings can inform community-based doula organisations, maternity healthcare services and policymakers. Further exploration of the factors that impact programme implementation, sustainability, strategic partnership potential and possible wider-reaching benefits is needed

Microstructural characterization of AISI 431 martensitic stainless steel laser-deposited coatings

High cooling rates during laser cladding of stainless steels may alter the microstructure and phase constitution of the claddings and consequently change their functional properties. In this research, solidification structures and solid state phase transformation products in single and multi layer AISI 431 martensitic stainless steel coatings deposited by laser cladding at different processing speeds are investigated by optical microscopy, Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), orientation imaging microscopy (OIM), ternary phase diagram, Schaeffler and TTT diagrams. The results of this study show how partitionless solidification and higher solidification rates alter the microstructure and phase constitution of martensitic stainless steel laser deposited coatings. In addition, it is shown that while different cladding speeds have no effect on austenite–martensite orientation relationship in the coatings, increasing the cladding speed has resulted in a reduction of hardness in deposited coatings which is in contrast to the common idea about obtaining higher hardness values at higher cladding speeds.

cAMP-Signalling Regulates Gametocyte-Infected Erythrocyte Deformability Required for Malaria Parasite Transmission.

Blocking Plasmodium falciparum transmission to mosquitoes has been designated a strategic objective in the global agenda of malaria elimination. Transmission is ensured by gametocyte-infected erythrocytes (GIE) that sequester in the bone marrow and at maturation are released into peripheral blood from where they are taken up during a mosquito blood meal. Release into the blood circulation is accompanied by an increase in GIE deformability that allows them to pass through the spleen. Here, we used a microsphere matrix to mimic splenic filtration and investigated the role of cAMP-signalling in regulating GIE deformability. We demonstrated that mature GIE deformability is dependent on reduced cAMP-signalling and on increased phosphodiesterase expression in stage V gametocytes, and that parasite cAMP-dependent kinase activity contributes to the stiffness of immature gametocytes. Importantly, pharmacological agents that raise cAMP levels in transmissible stage V gametocytes render them less deformable and hence less likely to circulate through the spleen. Therefore, phosphodiesterase inhibitors that raise cAMP levels in P. falciparum infected erythrocytes, such as sildenafil, represent new candidate drugs to block transmission of malaria parasites

Controlling the net: European approaches to content and access regulation

This article has been accepted for publication in the journal, Journal of Information Science [© CILIP] and the final (edited, revised and typeset) version of this paper will be published in Journal of Information Science, by SAGE Publications Ltd, All rights reserved. © CILIP. For more information please visit: http://jis.sagepub.co.uk