A sensitivity study of parameters affecting residual stress predictions in finite element modelling of the inertia friction welding process

This study presents a finite element (FE) model capable of predicting the final residual stress field in an inertia friction welded component of a CrMoV steel considering the elastic and inelastic components of strain resulting from mechanical deformation, temperature changes in the material and volumetric changes associated with phase transformations. The material database was improved to include the properties of the child phases involved in the polymorphic transformation during inertia friction welding (IFW) of CrMoV steels, i.e. austenite and quenched martensite, taking different approaches based on existent experimental data from the parent phase (tempered martensite) and material characterisation of the heat affected zone (HAZ) in weld trials. This is the only FE model available in the literature that takes into consideration the effects induced by the transformation strain component of multiple phases in the total strain generated during IFW. Several simulations were run using this FE model in order to address for the first time the sensitivity of the final residual stress field to the individual effects of the microstructural changes, the interrelationship of multiple phases, and to different processing parameters such as the die geometry, clamping history and cooling rates

Characterisation of material property variation across an inertia friction welded CrMoV steel component using the inverse analysis of nanoindentation data

In this study, a new application of the inverse analysis of the depth-sensing indentation technique based on the optimization theory has been satisfactorily demonstrated. The novel approach for determining the mechanical properties from experimental nanoindentation curves has been applied in order to generate the elastic–plastic stress–strain curves of three phases located across the joint of a like-to-like inertia friction weld of a CrMoV steel, i.e. the parent phase of tempered martensite and two child phases formed during the IFW process, martensite in the quenched and over-tempered condition. The inverse analysis carried out in this study consists of an optimization algorithm implemented in MATLAB, which compares an experimental nanoindentation curve with a predicted indentation curve generated by a 3D finite element model developed using the ABAQUS software; the optimization algorithm modifies the predicted curve by changing the material properties until the best fit to the experimental nanoindentation curve is found. The optimized parameters (mechanical properties) have been used to generate the stress–strain relationships in the elastic–plastic regime that can be used to simulate numerically the effects of the variation in material properties arising from phase transformations occurring across the joint during the IFW process of a CrMoV steel. The proposed inverse analysis was capable of fitting experimental load–depth (P–h) curves produced with a Nanoindentation Nanotest NTX unit from three characteristic regions located across the joint where the above mentioned phases are known to exist. The capability of the inverse analysis to build the stress–strain relationship in the elastic–plastic regime using the optimized mechanical properties of the parent metal has been validated using experimental data extracted from the compressive test of an axisymmetric sample of tempered martensite [1]. According to previous experimental studies, the presence of martensite in the quenched and over-tempered condition formed during the IFW of shaft sections of CrMoV steel are responsible of the 1.52:1 harder and 0.75:1 softer regions, compared to the region where the tempered martensite is located [2], [3] and [4]. These ratios are in very good agreement with the optimized magnitudes of yield stress provided by the inverse analysis, that is, 1.54:1 for the quenched martensite and 0.68:1 for the over-tempered martensite, compared to the optimized value of yield stress of the tempered martensite. Moreover, a relative difference of less than 1.5% between the experimental and predicted maximum depth (hmax) supports the capability of the method for extracting the elastic–plastic mechanical properties defining each of the indented regions

Spinning, Spooning and the Seductions of Flirtatious Masculinity in Contemporary Politics

This paper explores the relationships between masculinity, flirtation and fantasy within the promotional arena of politics and PR. Flirtation is associated with coquetry and play, connoting a lack of seriousness, and in political flirtation, the desire to move between different opinions and ideas. Flirtation is often linked with femininity. Yet against a backdrop of masculinity in crisis, the study of flirtation, with its connotations of ambiguity and frustrated desire, is useful to explore the uncertainties of masculinities today. Dilemmas about flirtation as a tantalising performance resonate with misgivings about the seductive nature of political spin and the desire of politicians to woo audiences by flirting to the camera. Taking examples of politicians such as Tony Blair, Gordon Brown and Barack Obama, this paper discusses the possibilities of flirtatious masculinity as a counter-hegemonic strategy within the symbolic battleground of Western politics, a struggle largely played out in print and digital media

Antimicrobial consumption and resistance in adult hospital inpatients in 53 countries:results of an internet-based global point prevalence survey

Summary: Background: The Global Point Prevalence Survey (Global-PPS) established an international network of hospitals to measure antimicrobial prescribing and resistance worldwide. We aimed to assess antimicrobial prescribing and resistance in hospital inpatients. Methods: We used a standardised surveillance method to collect detailed data about antimicrobial prescribing and resistance from hospitals worldwide, which were grouped by UN region. The internet-based survey included all inpatients (adults, children, and neonates) receiving an antimicrobial who were on the ward at 0800 h on one specific day between January and September, 2015. Hospitals were classified as primary, secondary, tertiary (including infectious diseases hospitals), and paediatric hospitals. Five main ward types were defined: medical wards, surgical wards, intensive-care units, haematology oncology wards, and medical transplantation (bone marrow or solid transplants) wards. Data recorded included patient characteristics, antimicrobials received, diagnosis, therapeutic indication according to predefined lists, and markers of prescribing quality (eg, whether a stop or review date were recorded, and whether local prescribing guidelines existed and were adhered to). We report findings for adult inpatients. Findings: The Global-PPS for 2015 included adult data from 303 hospitals in 53 countries, including eight lower-middle-income and 17 upper-middle-income countries. 86 776 inpatients were admitted to 3315 adult wards, of whom 29 891 (34·4%) received at least one antimicrobial. 41 213 antimicrobial prescriptions were issued, of which 36 792 (89·3%) were antibacterial agents for systemic use. The top three antibiotics prescribed worldwide were penicillins with β-lactamase inhibitors, third-generation cephalosporins, and fluoroquinolones. Carbapenems were most frequently prescribed in Latin America and west and central Asia. Of patients who received at least one antimicrobial, 5926 (19·8%) received a targeted antibacterial treatment for systemic use, and 1769 (5·9%) received a treatment targeting at least one multidrug-resistant organism. The frequency of health-care-associated infections was highest in Latin America (1518 [11·9%]) and east and south Asia (5363 [10·1%]). Overall, the reason for treatment was recorded in 31 694 (76·9%) of antimicrobial prescriptions, and a stop or review date in 15 778 (38·3%). Local antibiotic guidelines were missing for 7050 (19·2%) of the 36 792 antibiotic prescriptions, and guideline compliance was 77·4%. Interpretation: The Global-PPS showed that worldwide surveillance can be accomplished with voluntary participation. It provided quantifiable measures to assess and compare the quantity and quality of antibiotic prescribing and resistance in hospital patients worldwide. These data will help to improve the quality of antibiotic prescribing through education and practice changes, particularly in low-income and middle-income countries that have no tools to monitor antibiotic prescribing in hospitals. Funding: bioMérieux

Joining of advanced materials

Provides an unusually complete and readable compilation of the primary and secondary options for joining conventional materials in non-conventional ways. Provides unique coverage of adhesive bonding using both organic and inorganic adhesives, cements and mortars. Focuses on materials issues without ignoring issues related to joint design, production processing, quality assurance, process economics, and joining performance in service.Joining of advanced materials is a unique treatment of joining of both conventional and advanced metals andalloys, intermetallics, ceramics, glasses, polymers,