Modelling an abrasive wear experiment by the boundary element method

This Note presents a computational technique for simulating friction-induced wear in a tribology experiment on a plan/plan, ring-on-disc contact configuration. The boundary element method results in modest computing times and facilitates the mesh modifications used for tracking the wear profile evolution. A typical wear simulation result is presented and discussed

Socio-economic influences on anthropometric status in urban South African adolescents: sex differences in the Birth to Twenty Plus cohort.

OBJECTIVE: To investigate the associations of household and neighbourhood socio-economic position (SEP) with indicators of both under- and overnutrition in adolescents and to explore sex differences. DESIGN: Analysis of anthropometric, household and neighbourhood SEP data from the Birth to Twenty Plus cohort born in 1990. Anthropometric outcomes were BMI (thinness, overweight and obesity) and percentage body fat (%BF; low, high). Associations between these and the household wealth index, caregiver education and neighbourhood SEP tertile measures were examined using binary logistic regression. SETTING: Johannesburg-Soweto, South Africa. SUBJECTS: Adolescents aged 17-19 years (n 2019; 48·2% men). RESULTS: Women had a significantly higher combined prevalence of overweight/obesity (26·2%) than men (8·2%) whereas men had a significantly higher prevalence of thinness than women (22·2% v. 10·6%, respectively). Having a low neighbourhood social support index was associated with higher odds of high %BF in women (OR=1·59; 95% CI 1·03, 2·44). A low household wealth index was associated with lower odds of both overweight (OR=0·31; 95% CI 0·12, 0·76) and high %BF in men (OR=0·28; 95% CI 0·10, 0·78). A low or middle household wealth index was associated with higher odds of being thin in men (OR=1·90; 95% CI 1·09, 3·31 and OR=1·80; 95% CI 1·03, 3·15, respectively). For women, a low household wealth index was associated with lower odds of being thin (OR=0·49; 95% CI 0·25, 0·96). CONCLUSIONS: The study highlights that even within a relatively small urban area the nutrition transition manifests itself differently in men and women and across SEP indicators. Understanding the challenges for different sexes at different ages is vital in helping to plan public health services

On a multiscale strategy and its optimization for the simulation of combined delamination and buckling

This paper investigates a computational strategy for studying the interactions between multiple through-the-width delaminations and global or local buckling in composite laminates taking into account possible contact between the delaminated surfaces. In order to achieve an accurate prediction of the quasi-static response, a very refined discretization of the structure is required, leading to the resolution of very large and highly nonlinear numerical problems. In this paper, a nonlinear finite element formulation along with a parallel iterative scheme based on a multiscale domain decomposition are used for the computation of 3D mesoscale models. Previous works by the authors already dealt with the simulation of multiscale delamination assuming small perturbations. This paper presents the formulation used to include geometric nonlinearities into this existing multiscale framework and discusses the adaptations that need to be made to the iterative process in order to ensure the rapid convergence and the scalability of the method in the presence of buckling and delamination. These various adaptations are illustrated by simulations involving large numbers of DOFs

Neighbourhood and household socio-economic influences on diet and anthropometric status in urban South African adolescents

Background and Aims Many low- and middle-income countries are undergoing epidemiological and health transitions. South Africa has one of the highest prevalences of overweight and obesity in Sub-Saharan Africa. This research examined neighbourhood and household socio-economic influences on the risk of overweight and obesity in terms of anthropometric status and dietary intake among urban South African adolescents. A further aim was to conduct a qualitative study on the potential for religious groups such as Churches to be used as community-based organisations for obesity intervention. Methods A secondary analysis of neighbourhood and household socio-economic status (SES), anthropometric and dietary data was carried out on adolescents aged 17-19 years from the Birth to Twenty Plus cohort study in Johannesburg-Soweto. Qualitative data were collected through focus groups discussions and a community readiness survey with church leaders. Results No significant associations were observed between SES (household and neighbourhood) and energy, protein, fat, or carbohydrate intakes in males. Some significant associations were found between SES and dietary intake in females. Females had a higher prevalence of overweight and obesity than males (26.2% vs. 8.2%, p<0.0001). In males, poor household SES was associated with lower odds of overweight, fatness and high waist-to-height ratio (WHTR). For females, household SES was not significantly associated with overweight, fatness and high WHTR. The qualitative research showed that there was a very low level of community readiness among church leaders for obesity prevention programmes. Conclusions The dietary results suggest that the diet of these adolescents is transitioning to that seen in high income countries. It also highlights that even within the same relatively small urban area, nutrition transition does not affect different groups in uniform ways. The qualitative results indicate that programmes should focus around raising awareness of the problem of overweight/obesity in this community

Niveau d’énonciation, niveaux de culture en anglais informatique

Dans cet énoncé, les deux grandes variables ou paramètres sont les mots clés suivants : qualification professionnelle et compétence linguistique. Ils constituent la base de cette étude qui a pour objectif de démontrer l’incidence de ces deux paramètres sur le type d’enseignement de spécialité à dispenser. Ainsi l’enseignant doit bien maîtriser les deux axes et être capable de situer l’apprenant sur une grille à double entrée, à partir de laquelle il doit déduire les besoins de l’apprenant et ..

Tribological and corrosion wear of graphite ring against Ti6Al4V disk in artificial sea water

Severe degradations result from the friction of two antagonists in sea water environment. It is proposed to evaluate materials resistance to wear with a tribocorrosion experimental set-up which is mechanically and electrochemically instrumented. The method is illustrated with graphite and Ti6Al4V.The deposition of graphite on Ti6Al4V samples is observed and modifies the contact characteristics. Processes of graphite wear due to mechanical effect are characterised. Observations clearly indicate that Ti6Al4V degradations depend on the electrochemical potential imposed and more precisely on the electrochemical conditions in the contact zone

Effect of Isoenergetic Substitution of Cheese with Other Dairy Products on Blood Lipid Markers in the Fasted and Postprandial State: An Updated and Extended Systematic Review and Meta-analysis of Randomized Controlled Trials in Adults

Consumption of fat as part of a cheese matrix may differentially affect blood lipid responses, when compared to other dairy foods. This systematic review was conducted to compare the impact of consuming equal amounts of fat from cheese and other dairy products on blood lipid markers in the fasted and postprandial state. Searches of PubMed (Medline), Cochrane Central and Embase databases were conducted up to mid-June 2022. Eligible human randomized controlled trials (RCTs) investigated the effect of isoenergetic substitution of hard or semi-hard cheese with other dairy products on blood lipid markers. Risk of bias was assessed using the Cochrane RoB 2.0 tool. Random-effects meta-analyses assessed the effect of ≥2 similar dietary replacements on the same blood lipid marker. Of 1,491 identified citations, 10 articles were included (risk of bias: all some concerns). Pooled analyses of 7 RCTs showed a reduction in fasting total cholesterol, LDL-cholesterol and HDL-cholesterol concentrations following ≥ 14 d mean daily intake of 135 g cheese (weighted mean difference (WMD): −0.24 mmol/L; 95% CI: −0.34, −0.15; I2 = 59.8 %, WMD: −0.19 mmol/L; 95% CI: −0.27, −0.12; I2 = 42.8%, and WMD: −0.04 mmol/L; 95% CI: −0.08, −0.00; I2 = 58.6%, respectively) relative to ∼52 g/d butter. We found no evidence of a benefit from replacing cheese for ≥ 14 d with milk on fasting blood lipid markers (n = 2). Limited postprandial RCTs, described in narrative syntheses, suggested that cheese-rich meals may induce differential fed-state lipid responses compared to some other dairy matrix structures, but not butter (n ≤ 2). In conclusion, these findings indicate that dairy fat consumed in the form of cheese has a differential effect on blood lipid responses relative to some other dairy food structures. However, owing to considerable heterogeneity and limited studies, further confirmation from RCTs is warranted. This systematic review protocol was registered at https://www.crd.york.ac.uk/PROSPERO/ as CRD42022299748

Niveau d’énonciation, niveaux de culture en anglais informatique

Dans cet énoncé, les deux grandes variables ou paramètres sont les mots clés suivants : qualification professionnelle et compétence linguistique. Ils constituent la base de cette étude qui a pour objectif de démontrer l’incidence de ces deux paramètres sur le type d’enseignement de spécialité à dispenser. Ainsi l’enseignant doit bien maîtriser les deux axes et être capable de situer l’apprenant sur une grille à double entrée, à partir de laquelle il doit déduire les besoins de l’apprenant et ..