Residual stresses in condition monitoring and repair of thermal power generation components

Residual stresses have a significant impact on fatigue and fracture of engineering components and structures, with an effect that is largely dependent on the sign of the residual stress relative to that of the applied stress, i.e. on whether they add to, or subtract from, the applied stress. The present paper will emphasise the importance of detailed knowledge of residual stresses to applications in thermal power generation. The context of the examples is condition monitoring and repair procedures where assessment of the influence of residual stress fields is important to both fatigue and fracture performance, and to certification of the repair procedure itself. The main conclusion in the paper is that the innovative use of solid-state friction taper hydro-pillar processes can offer additional capability in condition monitoring of through-thickness creep damage in thermal power plant, as well as provide cost-effective local repair of creep or fatigue damage in, for example, thick-walled steam pipe and blade-disc attachment holes

Post-traumatic, intrapulmonary arteriovenous fi stula: Diagnosis by trans-oesophageal echocardiography

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Post-traumatic, intrapulmonary arteriovenous fistula : diagnosis by trans-oesophageal echocardiography

CITATION: Van der Bijl, P., Herbst, P. G., Doubell, A. F. & Pecoraro, A. J. 2015. Post-traumatic, intrapulmonary arteriovenous fistula : diagnosis by trans-oesophageal echocardiography. SA Heart, 12(1):26-27, doi:10.24170/12-1-1731.The original publication is available at http://www.journals.ac.za/index.php/SAHJAbstract not availableAFRIKAANSE OPSOMMING: Geen opsomming beskikbaarhttp://www.journals.ac.za/index.php/SAHJ/article/view/1731Publisher's versio

Speckle tracking echocardiography in acute lupus myocarditis : comparison to conventional echocardiography

CITATION: Du Toit, R., et al. 2017. Speckle tracking echocardiography in acute lupus myocarditis : comparison to conventional echocardiography. Echo Research and Practice, 4(2):9-19, doi:10.1530/ERP-17-0005.The original publication is available at http://www.echorespract.comAims: Lupus myocarditis occurs in 5–10% of patients with systemic lupus erythematosus (SLE). No single feature is diagnostic of lupus myocarditis. Speckle tracking echocardiography (STE) can detect subclinical left ventricular dysfunction in SLE patients, with limited research on its utility in clinical lupus myocarditis. We report on STE in comparison to conventional echocardiography in patients with clinical lupus myocarditis. Methods and results: A retrospective study was done at a tertiary referral hospital in South Africa. SLE patients with lupus myocarditis were included and compared to healthy controls. Echocardiographic images were reanalyzed, including global longitudinal strain through STE. A poor echocardiographic outcome was defined as final left ventricular ejection fraction (LVEF) <40%. 28 SLE patients fulfilled the criteria. Global longitudinal strain correlated with global (LVEF: r = −0.808; P = 0.001) and regional (wall motion score: r = 0.715; P < 0.001) function. In patients presenting with a LVEF ≥50%, global longitudinal strain (P = 0.023), wall motion score (P = 0.005) and diastolic function (P = 0.004) were significantly impaired vs controls. Following treatment, LVEF (35–47% (P = 0.023)) and wall motion score (1.88–1.5 (P = 0.017)) improved but not global longitudinal strain. Initial LVEF (34%; P = 0.046) and global longitudinal strain (−9.5%; P = 0.095) were lower in patients with a final LVEF <40%. Conclusions: This is the first known report on STE in a series of patients with clinical lupus myocarditis. Global longitudinal strain correlated with regional and global left ventricular function. Global longitudinal strain, wall motion score and diastolic parameters may be more sensitive markers of lupus myocarditis in patients presenting with a preserved LVEF ≥50%. A poor initial LVEF and global longitudinal strain were associated with a persistent LVEF <40%. Echocardiography is a non-invasive tool with diagnostic and prognostic value in lupus myocarditis.http://www.echorespract.com/content/4/2/9.full?sid=c26dad46-d821-4592-8805-ad0bba805a46Publisher's versio