Using acoustic emission to characterize friction and wear in dry sliding steel contacts

Acoustic emission (AE) was recorded during tribological tests on 52,100 steel specimens under different loads. AE signals were transformed to the frequency domain using a Fast Fourier Transform and parameters such as power, RMS amplitude, mean frequency, and energy were analyzed and compared with friction coefficient and wear volume measurements. Results show that certain acoustic frequencies reflect friction while others reflect wear. If frequencies are chosen optimally, AE and friction signals are highly correlated (Pearson coefficients >0.8). SEM and Raman analysis reveal how plastic deformation and oxide formation affect friction, wear and AE simultaneously. AE recordings contains more information than conventional friction and wear volume measurements and are more sensitive to changes in mechanism. This all demonstrates AE's potential as a tool to monitor tribological behavior.This work was supported by the Overseas Study Program of Jiangsu Higher Education Institutions; the Natural Science Foundation of Jiangsu Province, China (Grant no. BK20160353); the Natural Science Foundation of Jiangsu Higher Education Institutions (Grant no. 16KJB460032); the Key Laboratory of Suzhou (SZS201815); the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP) (Grant no. PPZY2015B186) and the Scientific Research Foundation of SIIT (Grant no. 2017kyqd015)

Exploiting air cushion effects to optimise a superhydrophobic/hydrophilic patterned liquid ring sealed air bearing

© 2019 Elsevier Ltd A thrust bearing consisting of an air cushion formed within a liquid ring has been developed, which takes advantage of the Laplace pressure induced by the liquid/air surface tension. As forces induced by Laplace pressure and surface tension scales down much more slowly than gravity and inertial forces, such a bearing has great potential when scaled down to the micro-scale. The liquid ring between the rotor and the stator of the bearing is anchored there by alternating hydrophilic and superhydrophobic patterns. An important discovery is that the performance of this bearing is greatly enhanced by the sealed cushion of air within the ring. This air cushion and thin liquid ring arrangement mean that the solid/solid contact of the bearing is replaced by solid/air and solid/liquid contact which significantly reduces the friction and wear. The factors which affects the performance of the bearing have been studied both experimentally and numerically providing results that can be used to optimise the design of this new type of bearing.The project was funded by the CSC Imperial Scholarship (Grant no. 201700260048). The authors also acknowledge the support received by the Engineering and Physical Sciences Research Council via Professor Dini's Established Career Fellowship, EP/N025954/1

Lactobacillus reuteri: novajlija u tehnologiji mlijeka

Lactobacillus reuteri is an inhabitant of the gastrointestinal of humans and animals and has been isolated also from food (sausages, cheese, sour dough). It is suggested that L. reuteri, a dominant heterofermentative Lactobacillus species with unique taits, may interact beneficially in stabilizing the intestinal microflora, thus, having a protective function against pathogenic microorganisms. L. reuteri as a newcomer in dairy technology and products are appearing on the market which are supplemented with this microorganism (sweet milk and fermented milk products). It is not quite clear which role L. reuteri plays in the intestinal ecosystem and how important it is for health and well-being of the host-organism. L. reuteri is an obligatory heterofermentative Lactobacillus and produces under certain conditions reuterin (ß-hydroxypropionaldehyd), a potent broad-spectrum antimicrobial substance acting as inhibitor of a number of undersirable bacteria, yeasts, fungi and protozoa.Lactobacillus reuteri je stanovnik gastrointestinalnog trakta ljudi i Životinja, a izoliranje i iz hrane (kobasice, sir, kiselo tijesto). Navodi se da je L. reuteri dominantna heterofermentativna vrsta Lactobacillus jedinstvenih svojstava. Mote povoljno djelovati na stabiliziranje intestinalne mikroflore, prema tome, štiti od patogenih mikroorganizama. L. reuteri je novajlija u tehnologiji mlijeka i proizvodima koji se pojavljuju na tržištu, a taj se mikroorganizam dodaje (slatko mlijeko i fermentirani mliječni proizvodi). Nije posve jasna uloga L. reuteri u intestinalnom ekosustavu i koliko je važan za zdravlje i dobrobit domaćina. L. reuteri je obligatni heterofermentativni Lactobacillus i proizvodi u određenim uvjetima reuterin (ß-hidroksipropionaldehid), antimikrobnu tvar širokog spektra, koja priječi razvoj niza nepoželjnih bakterija, kvasaca, gljiva i protozoa

Transient aspects of plasma luminescence induced by triboelectrification of polymers

Transient electric gas discharges that occur around sliding interfaces during contact electrification of polymers were studied at millisecond timescales and with micrometre resolution. Deduced vibrational temperatures indicate cold plasma resulting from positive corona discharge. At millisecond timescales, previously unseen rapid discharge events are observed, and modelling suggests that these result from streamer development, triggered by electron emission from the polymer surface. Those which occur over a period of several seconds are shown to be caused by competition between charge generation and the formation of polymer films. The findings explain the interplay between charging and plasma generation and their dependence on wear processes.UK Engineering and Physical Sciences Research Council (EP/J002100/1), Additional equipment funding provided by the Taiho Kogyo Tribology Research Foundation (11A01). Spanish Ministry of Economy, Industry and Competitivity through the grant BIA2016-79582-

Respiratory rehabilitation after acute exacerbation of COPD may reduce risk for readmission and mortality – a systematic review

BACKGROUND: Acute exacerbations of chronic obstructive pulmonary disease (COPD) represent a major burden for patients and health care systems. Respiratory rehabilitation may improve prognosis in these patients by addressing relevant risk factors for exacerbations such as low exercise capacity. To study whether respiratory rehabilitation after acute exacerbation improves prognosis and health status compared to usual care, we quantified its effects using meta-analyses. METHODS: Systematic review of randomized controlled trials identified by searches in six electronic databases, contacts with experts, hand-searches of bibliographies of included studies and conference proceedings. We included randomized trials comparing the effect of respiratory rehabilitation and usual care on hospital admissions, health-related quality of life (HRQL), exercise capacity and mortality in COPD patients after acute exacerbation. Two reviewers independently selected relevant studies, extracted the data and evaluated the study quality. We pooled the results using fixed effects models where statistically significant heterogeneity (p < or = 0.1) was absent. RESULTS: We identified six trials including 230 patients. Respiratory rehabilitation reduced the risk for hospital admissions (pooled relative risk 0.26 [0.12-0.54]) and mortality (0.45 [0.22-0.91]). Weighted mean differences on the Chronic Respiratory Questionnaire were 1.37 (95% CI 1.13-1.61) for the fatigue domain, 1.36 (0.94-1.77) for emotional function and 1.88 (1.67-2.09) for mastery. Weighted mean differences for the St. Georges Respiratory Questionnaire total score, impacts and activities domains were -11.1 (95% CI -17.1 to -5.2), -17.1 (95% CI -23.6 to -10.7) and -9.9 (95% CI -18.0 to -1.7). In all trials, rehabilitation improved exercise capacity (64-215 meters in six-minute walk tests and weighted mean difference for shuttle walk test 81 meter, 95% CI 48-115). CONCLUSION: Evidence from six trials suggests that respiratory rehabilitation is effective in COPD patients after acute exacerbation. Larger trials, however, are needed to further investigate the role of respiratory rehabilitation after acute exacerbation and its potential to reduce costs caused by COPD

Outcomes in studies regarding older patients with prostate cancer: A systematic review

INTRODUCTION: Older patients are often deemed ineligible for clinical research, and many frequently-used endpoints and outcome measures are not as relevant for older patients for younger ones. This systematic review aimed to present an overview of outcomes used in clinical research regarding patients over the age of 65 years with prostate cancer. MATERIALS AND METHODS: PubMed and Embase were systematically searched to identify studies on prostate cancer (treatment) in patients aged ≥65 between 2016 and 2023. Data on title, study design, number of participants and age, stage of disease, treatment, and investigated outcomes were synthesized and descriptively analyzed. RESULTS: Sixty-eight studies were included. Of these most included patients over 65 years, while others used a higher age. Overall, 39 articles (57.3%) reported on survival-related outcomes, 22 (32.4%) reported on progression of disease and 38 (55.9%) used toxicity or adverse events as an outcome measure. Health-related quality of life and functional outcomes were investigated in 29.4%, and cognition in two studies. The most frequently investigated survival-related outcomes were overall and cancer-specific survival (51.3%); however, 38.5% only studied overall survival. DISCUSSION: The main focus of studies included in this review remains survival and disease progression. There is limited attention for health-related quality of life and functional status, although older patients often prioritize the latter. Future research should incorporate outcome measures tailored to the aged population to improve care for older patients with prostate cancer

Nationwide implementation of the self-management program "Living well with COPD": Process and effectiveness evaluation using a mixed-methods approach.

To evaluate the nationwide implementation of the "Living well with COPD" program by the Swiss Lung Association in various cantons in Switzerland. For the process evaluation, we used qualitative (interview, focus group) and quantitative (questionnaires, documentation analysis) methods to assess the implementation outcomes reach, dose, fidelity and acceptability. For the effectiveness, we performed a pre-post analysis of patient data collected at baseline and program end (after 14 months). Seven Cantonal Lung Associations implemented the program into their services according to plan, conducted it 13 times and included 122 COPD patients. Patients' attendance rate was 81% and coaches' fidelity to protocol 94%. Acceptance and satisfaction of all involved persons was high. Integration of the coaches' additional workload, uncertainties regarding roles and responsibilities and sustainable reimbursement were major challenges. Patients significantly improved in COPD specific quality of life and increased exercise capacity with on average 3.2 more repetitions in the 1-minute sit-to-stand test. The program was successfully implemented throughout Switzerland with high acceptability and positive association with patients' quality of life. Our findings support the broader multiplication throughout Switzerland and serves the international community since it is one of the first nationwide implementations beyond study settings

Combining scores from different patient reported outcome measures in meta-analyses: when is it justified?

BACKGROUND: Combining outcomes and the use of standardized effect measures such as effect size and standardized response mean across instruments allows more comprehensive meta-analyses and should avoid selection bias. However, such analysis ideally requires that the instruments correlate strongly and that the underlying assumption of similar responsiveness is fulfilled. The aim of the study was to assess the correlation between two widely used health-related quality of life instruments for patients with chronic obstructive pulmonary disease and to compare the instruments' responsiveness on a study level. METHODS: We systematically identified all longitudinal studies that used both the Chronic Respiratory Questionnaire (CRQ) and the St. George's Respiratory Questionnaire (SGRQ) through electronic searches of MEDLINE, EMBASE, CENTRAL and PubMed. We assessed the correlation between CRQ (scale 1 – 7) and SGRQ (scale 1 – 100) change scores and compared responsiveness of the two instruments by comparing standardized response means (change scores divided by their standard deviation). RESULTS: We identified 15 studies with 23 patient groups. CRQ change scores ranged from -0.19 to 1.87 (median 0.35, IQR 0.14–0.68) and from -16.00 to 3.00 (median -3.00, IQR -4.73–0.25) for SGRQ change scores. The correlation between CRQ and SGRQ change scores was 0.88. Standardized response means of the CRQ (median 0.51, IQR 0.19–0.98) were significantly higher (p < 0.001) than for the SGRQ (median 0.26, IQR -0.03–0.40). CONCLUSION: Investigators should be cautious about pooling the results from different instruments in meta-analysis even if they appear to measure similar constructs. Despite high correlation in changes scores, responsiveness of instruments may differ substantially and could lead to important between-study heterogeneity and biased meta-analyses

Respiratory rehabilitation after acute exacerbation of COPD may reduce risk for readmission and mortality – a systematic review

BACKGROUND: Acute exacerbations of chronic obstructive pulmonary disease (COPD) represent a major burden for patients and health care systems. Respiratory rehabilitation may improve prognosis in these patients by addressing relevant risk factors for exacerbations such as low exercise capacity. To study whether respiratory rehabilitation after acute exacerbation improves prognosis and health status compared to usual care, we quantified its effects using meta-analyses. METHODS: Systematic review of randomized controlled trials identified by searches in six electronic databases, contacts with experts, hand-searches of bibliographies of included studies and conference proceedings. We included randomized trials comparing the effect of respiratory rehabilitation and usual care on hospital admissions, health-related quality of life (HRQL), exercise capacity and mortality in COPD patients after acute exacerbation. Two reviewers independently selected relevant studies, extracted the data and evaluated the study quality. We pooled the results using fixed effects models where statistically significant heterogeneity (p ≤ 0.1) was absent. RESULTS: We identified six trials including 230 patients. Respiratory rehabilitation reduced the risk for hospital admissions (pooled relative risk 0.26 [0.12–0.54]) and mortality (0.45 [0.22–0.91]). Weighted mean differences on the Chronic Respiratory Questionnaire were 1.37 (95% CI 1.13–1.61) for the fatigue domain, 1.36 (0.94–1.77) for emotional function and 1.88 (1.67–2.09) for mastery. Weighted mean differences for the St. Georges Respiratory Questionnaire total score, impacts and activities domains were -11.1 (95% CI -17.1 to -5.2), -17.1 (95% CI -23.6 to -10.7) and -9.9 (95% CI -18.0 to -1.7). In all trials, rehabilitation improved exercise capacity (64–215 meters in six-minute walk tests and weighted mean difference for shuttle walk test 81 meter, 95% CI 48–115). CONCLUSION: Evidence from six trials suggests that respiratory rehabilitation is effective in COPD patients after acute exacerbation. Larger trials, however, are needed to further investigate the role of respiratory rehabilitation after acute exacerbation and its potential to reduce costs caused by COPD

Thermal Behaviour of Synovene and Oleamide in Oil Adsorbed on Steel

Abstract: Oleamide and Synovene lubricant additives when mixed together show a clear co-operative effect leading to friction and wear reduction. Sum Frequency Generation vibrational spectroscopy has been used to record in situ spectra of these additives with the aim of understanding the behaviour of these molecules when adsorbed on steel immersed in a model base oil at pre-selected temperatures. The spectra of the individual components and of mixtures have been recorded up to 130 °C. Individual spectra from both molecules have been distinguished using per-deuterated oleamide. The temperature at which maximum ordered adsorption of pure Synovene molecules occurs drops from ~ 130 to ~ 70 °C in the mixture with oleamide. Our results show that co-adsorption occurs, which causes a change in net polar orientation of the oleamide component suggesting the hydrocarbon chains of the oleamide molecules reverse their polar orientation when Synovene is present. The net effect of co-adsorption and change in orientation as well as conformation of the two molecules could explain the reduction of friction and wear observed at the metal–metal interface