44 research outputs found
Tribological properties of duplex plasma oxidised, nitrided and PVD coated Ti-6Al-4V
The authors gratefully acknowledge financial support from the UK
Technology Strategy Board under Technology Programme project
TP/22076, for underpinning research carried out at Sheffield University,
on which the work presented in this paper was partially based.Sequential triode plasma oxidation and nitriding have been used to provide enhanced load support for
physical vapour deposited (PVD) hard coatings. The diffusion process has been designed to maximise process
efficiency and coating adhesion, thereby significantly improving the tribological properties of the Ti–6Al–4V
alloy — particularly at high contact pressures. This has been demonstrated using unlubricated linear
reciprocating-sliding ball-on-plate wear tests and micro-scratch adhesion testing. Also, surface micro-
profilometry, nano/micro-indentation hardness testing, scanning electron microscopy (SEM), energy-
dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and glow-discharge optical emission
spectroscopy (GDOES) data are presented to corroborate the effect of the several plasma diffusion processes
and duplex diffusion/coating combinations discussed here. The results presented show that the novel
processing technique developed permits the use of oxygen diffusion in order to obtain relatively large case
depths in shorter treatment times without compromising the adhesion strength of subsequently deposited
PVD layers.peer-reviewe
An investigation into the effect of Triode Plasma Oxidation (TPO) on the tribological properties of Ti6Al4V
The authors gratefully acknowledge the UK Technology Strategy
Board for financial support under the collaborative project LIB-TEC,
project No TP 22076.Improving the tribological properties of titanium alloys has been the subject of extensive research for many
years. A number of thermochemical processes have been developed for that purpose. In this study, surface
hardening of Ti6Al4V is achieved by Triode Plasma Oxidation (TPO) which differs from conventional diode
plasma treatments through the use of a third electrode; a negatively biased tungsten filament to enhance
the ionisation levels in the plasma. The resultant surface generally consists of a top oxide layer with an oxy-
gen diffusion zone lying immediately underneath it. The effects of process parameters such as substrate tem-
perature, current density and oxygen partial pressure have been investigated. Surface hardness
measurements at various indentation loads were carried out to assess the changes in hardness with depth
across the diffusion layer. The hardness profiles obtained confirmed the gradual decrease in hardness with
treatment depth and provided an indication of the thickness of the hardened layer produced. Ball-on-plate
reciprocating sliding wear data and glancing angle XRD analyses of the oxidised samples are also presented.
The results indicate that a harder and deeper case is achieved at both high substrate temperature and high
oxygen partial pressure. Furthermore, XRD data show that the substrate temperature strongly affects the
structure of the oxide layer produced. All TPO-treated samples exhibit significantly better wear performance
compared to the untreated material.peer-reviewe
Corrigendum to ‘Guideline No. 412: Laparoscopic Entry for Gynaecological Surgery’ [Journal of Obstetrics and Gynaecology Canada 43 (2021) 376−389](S1701216320310343)(10.1016/j.jogc.2020.12.012)
The authors regret that the print version of this article contained the incorrect reference 51. Reference 51 should have been: Bernante P, Foletto M, Toniato A. Creation of pneumoperitoneum using a bladed optical trocar in morbidly obese patients: technique and results. Obes Surg. 2008 Aug;18(8):1043-6. doi: 10.1007/s11695-008-9497-8. The online version of the article has now been corrected The authors would like to apologize for any confusion this caused. DOI of original article: https://doi.org/10.1016/j.jogc.2021.03.00
Enabling lightweight, high load aero-bearings
Environmental and commercial considerations are strongly driving research into weight saving in
aircraft. In this research, innovative manufacturing processes were developed to produce
lightweight titanium alloy bearings capable of withstanding high bearing pressures. This will
enable the replacement of heavier conventional bearing materials with titanium alloy bearings of
the same size thereby saving weight. Plasma processing and PVD coating techniques were
refined and combined and a sound scientific understanding of the resulting novel processes
developed to assure high performance, reliability and repeatability. These techniques were
applied to test discs and small bearing (bush) samples, which were tested under progressively
greater loads (pressures). FEA was also used to evaluate pressure distribution in a bush test
assembly. The novel treatment has potential applications for many bearings and bearing surfaces
throughout aircraft.peer-reviewe
Improving uptake of Fracture Prevention drug treatments: a protocol for Development of a consultation intervention (iFraP-D).
Funder: Wellcome TrustINTRODUCTION: Prevention of fragility fractures, a source of significant economic and personal burden, is hindered by poor uptake of fracture prevention medicines. Enhancing communication of scientific evidence and elicitation of patient medication-related beliefs has the potential to increase patient commitment to treatment. The Improving uptake of Fracture Prevention drug treatments (iFraP) programme aims to develop and evaluate a theoretically informed, complex intervention consisting of a computerised web-based decision support tool, training package and information resources, to facilitate informed decision-making about fracture prevention treatment, with a long-term aim of improving informed treatment adherence. This protocol focuses on the iFraP Development (iFraP-D) work. METHODS AND ANALYSIS: The approach to iFraP-D is informed by the Medical Research Council complex intervention development and evaluation framework and the three-step implementation of change model. The context for the study is UK fracture liaison services (FLS), which enact secondary fracture prevention. An evidence synthesis of clinical guidelines and Delphi exercise will be conducted to identify content for the intervention. Focus groups with patients, FLS clinicians and general practitioners and a usual care survey will facilitate understanding of current practice, and investigate barriers and facilitators to change. Design of the iFraP intervention will be informed by decision aid development standards and theories of implementation, behaviour change, acceptability and medicines adherence. The principles of co-design will underpin all elements of the study through a dedicated iFraP community of practice including key stakeholders and patient advisory groups. In-practice testing of the prototype intervention will inform revisions ready for further testing in a subsequent pilot and feasibility randomised trial. ETHICS AND DISSEMINATION: Ethical approval was obtained from North West-Greater Manchester West Research Ethics Committee (19/NW/0559). Dissemination and knowledge mobilisation will be facilitated through national bodies and networks, publications and presentations. TRIAL REGISTRATION NUMBER: researchregistry5041
Ethnic and social inequalities in COVID-19 outcomes in Scotland:protocol for early pandemic evaluation and enhanced surveillance of COVID-19 (EAVE II)
Introduction: Evidence from previous pandemics, and the current COVID-19 pandemic, has found that risk of infection/severity of disease is disproportionately higher for ethnic minority groups, and those in lower socioeconomic positions. It is imperative that interventions to prevent the spread of COVID-19 are targeted towards high-risk populations. We will investigate the associations between social characteristics (such as ethnicity, occupation and socioeconomic position) and COVID-19 outcomes and the extent to which characteristics/risk factors might explain observed relationships in Scotland.
The primary objective of this study is to describe the epidemiology of COVID-19 by social factors. Secondary objectives are to (1) examine receipt of treatment and prevention of COVID-19 by social factors; (2) quantify ethnic/social differences in adverse COVID-19 outcomes; (3) explore potential mediators of relationships between social factors and SARS-CoV-2 infection/COVID-19 prognosis; (4) examine whether occupational COVID-19 differences differ by other social factors and (5) assess quality of ethnicity coding within National Health Service datasets.
Methods and analysis: We will use a national cohort comprising the adult population of Scotland who completed the 2011 Census and were living in Scotland on 31 March 2020 (~4.3 million people). Census data will be linked to the Early Assessment of Vaccine and Anti-Viral Effectiveness II cohort consisting of primary/secondary care, laboratory data and death records. Sensitivity/specificity and positive/negative predictive values will be used to assess coding quality of ethnicity. Descriptive statistics will be used to examine differences in treatment and prevention of COVID-19. Poisson/Cox regression analyses and mediation techniques will examine ethnic and social differences, and drivers of inequalities in COVID-19. Effect modification (on additive and multiplicative scales) between key variables (such as ethnicity and occupation) will be assessed.
Ethics and dissemination: Ethical approval was obtained from the National Research Ethics Committee, South East Scotland 02. We will present findings of this study at international conferences, in peer-reviewed journals and to policy-makers
Vitamin D and SARS-Co V-2 virus/COVID-19 disease
Summary for social mediaVitamin D is essential for good health, especially bone and muscle health. Many people have low blood levels of vitamin D, especially in winter or if confined indoors, because summer sunshine is the main source of vitamin D for most people. Government vitamin D intake recommendations for the general population are 400 IU (10 µg) per day for the UK7 and 600 IU (15 µg) per day for the USA (800 IU (20 µg) per day for >70 years) and the EU.9 Taking a daily supplement (400 IU /day (10 µg/day) in the UK) and eating foods that provide vitamin D is particularly important for those self-isolating with limited exposure to sunlight. Vitamin D intakes greater than the upper limit of 4000 IU (100 µg) per day may be harmful and should be avoided unless under personal medical/clinical advice by a qualified health professional