Automated Impact Damage Detection Technique for Composites Based on Thermographic Image Processing and Machine Learning Classification.

Composite materials are one of the primary structural components in most current transportation applications, such as the aerospace industry. Composite material diagnostics is a promising area in the fight against structural damage in aircraft and spaceships. Detection and diagnostic technologies often provide analysts with a valuable and rapid mechanism to monitor the health and safety of composite materials. Although many attempts have been made to develop damage detection techniques and make operations more efficient, there is still a need to develop/improve existing methods. Pulsed thermography (PT) technology was used in this study to obtain healthy and defective data sets from custom-designed composite samples having similar dimensions but different thicknesses (1.6 and 3.8). Ten carbon fibre-reinforced plastic (CFRP) panels were tested. The samples were subjected to impact damage of various energy levels, ranging from 4 to 12 J. Two different methods have been applied to detect and classify the damage to the composite structures. The first applied method is the statistical analysis, where seven different statistical criteria have been calculated. The final results have proved the possibility of detecting the damaged area in most cases. However, for a more accurate detection technique, a machine learning method was applied to thermal images; specifically, the Cube Support Vector Machine (SVM) algorithm was selected. The prediction accuracy of the proposed classification models was calculated within a confusion matrix based on the dataset patterns representing the healthy and defective areas. The classification results ranged from 78.7% to 93.5%, and these promising results are paving the way to develop an automated model to efficiently evaluate the damage to composite materials based on the non-distractive testing (NDT) technique.

Evaluation and Selection of Video Stabilization Techniques for UAV-Based Active Infrared Thermography Application.

Unmanned Aerial Vehicles (UAVs) that can fly around an aircraft carrying several sensors, e.g., thermal and optical cameras, to inspect the parts of interest without removing them can have significant impact in reducing inspection time and cost. One of the main challenges in the UAV based active InfraRed Thermography (IRT) inspection is the UAV's unexpected motions. Since active thermography is mainly concerned with the analysis of thermal sequences, unexpected motions can disturb the thermal profiling and cause data misinterpretation especially for providing an automated process pipeline of such inspections. Additionally, in the scenarios where post-analysis is intended to be applied by an inspector, the UAV's unexpected motions can increase the risk of human error, data misinterpretation, and incorrect characterization of possible defects. Therefore, post-processing is required to minimize/eliminate such undesired motions using digital video stabilization techniques. There are number of video stabilization algorithms that are readily available; however, selecting the best suited one is also challenging. Therefore, this paper evaluates video stabilization algorithms to minimize/mitigate undesired UAV motion and proposes a simple method to find the best suited stabilization algorithm as a fundamental first step towards a fully operational UAV-IRT inspection system.

Induction thermography of steel coupons with cracks.

The induction thermography technique was assessed experimentally and numerically on notched steel coupons using two coil configurations: straight line and loop conditions. The coupons had different lengths of fatigue crack varying from zero to 3 mm. The numerical predictions showed that the peak temperature was always located at the crack tip or the notch tip position. The loop coil resulted in higher temperatures than those of the straight line coil. Results showed that the numerical methods effectively supported the application assessment of this nondestructive evaluation (NDE) technique for the steel material, but crack geometry remains a challenge as the exact shape of a natural crack is typically unknown. It is shown that induction thermography can detect a crack as small as 1 mm in the notched steel coupons. Commentary on the application of the NDE technique with the numerical modeling support was provided.

Pulsed micro-laser line thermography on submillimeter porosity in carbon fiber reinforced polymer composites: experimental and numerical analyses for the capability of detection.

In this article, pulsed micro-laser line thermography (pulsed micro-LLT) was used to detect the submillimeter porosities in a 3D preformed carbon fiber reinforced polymer composite specimen. X-ray microcomputed tomography was used to verify the thermographic results. Then, finite element analysis was performed on the corresponding models on the basis of the experimental results. The same infrared image processing techniques were used for the experimental and simulation results for comparative purposes. Finally, a comparison of experimental and simulation postprocessing results was conducted. In addition, an analysis of probability of detection was performed to evaluate the detection capability of pulsed micro-LLT on submillimeter porosity.

Incidence, diagnostic methods, and evolution of left ventricular thrombus in patients with anterior myocardial infarction and low left ventricular ejection fraction: a prospective multicenter study.

BACKGROUND AND OBJECTIVES: We aimed to assess the incidence and evolution of left ventricular (LV) thrombi in a high-risk population of patients with LV systolic dysfunction after anterior myocardial infarction (ant-MI). We also compared the accuracy of transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging with contrast-delayed enhancement (CMR-DE) in detecting LV thrombi. METHODS: We prospectively included 100 consecutive patients with LV ejection fraction (LVEF) <45% at the first TTE performed <7 days after ant-MI. A second evaluation with TTE and CMR-DE (by blinded examiners) was performed at 30 days. A third TTE and assessment of clinical status were performed between 6 and 12 months after ant-MI. RESULTS: Patients (males 71%; mean age 59.1 ± 12.1 years; mean LVEF 33.5% ± 6.0%) were included at a median of 5.5 days (interquartile range 25th-75th percentile 4.25-6.0 days) after ant-MI. Thrombi were detected among 26 (26%) patients at a median of 12.0 days after ant-MI (7 patients at 1-7 days after MI; 15 at 8-30 days; and 4 after day 30). Sensitivity and specificity for LV thrombi detection were 94.7% and 98.5%, respectively, for TTE as compared with CMR-DE. Most thrombi (n = 24; 92.3%) disappeared after triple antithrombotic therapy (vitamin K antagonist in addition to dual antiplatelet therapy). CONCLUSION: Left ventricular thrombus is a frequent complication after ant-MI with systolic dysfunction. When a search for thrombus is prespecified, the accuracy of TTE is high as compared with CMR-DE. The best antithrombotic strategy is not known.

A familial form of conduction defect related to a mutation in the PRKAG2 gene.

We describe four members of the same family with a very similar ECG pattern characterized by conduction defects (right bundle branch block, frequent left anterior hemiblock, atrial hypertrophy, and sometimes severe nodal dysfunction) contrasting with a short PR interval. Significant clinical events were reported only after 60 years of age. A mutation in the gamma2 subunit of the AMP activated protein kinase gene (PRKAG2) was identified in the four members of the family, with an autosomal dominant inheritance. The phenotype observed in this family appears different from that previously described as associated with this gene as neither left ventricular hypertrophy nor Wolff-Parkinson-White syndrome was present. These findings extend the phenotype associated with the PRKAG2 gene and emphasize an additional cause of familial conduction defect.

[Changes in the management of cardiac arrest]. / Changements dans la prise en charge de l'arrêt cardiaque.

NEW RECOMMENDATIONS: for cardio-pulmonary resuscitation Methods such as mouth to mouth or the search for a pulse, until now the fundamental preliminaries, have now become second line. Everything must be organised to allow for defibrillation as rapidly as possible. NEW MODALITIES FOR CARDIAC MASSAGE: The frequency of compressions recommended is currently 100 per minute in the adult with a rhythm of compression-ventilation reaching 15/2 before intubation. Concerning the haemodynamic agents for cardiac arrest, the efficacy of high doses of adrenalin is not greater than with conventional doses. Vasopressin is not superior to intravenous adrenalin regarding survival at 24 hrs exepet in case of asystoly. Dopamine at a "renal" dose is no longer used. ANTIARRYTHMICS: Amiodarone is part of the decisional tree in the case of ventricular fibrillation or ventricular tachycardia without a pulse. Semi-automatic defibrillator accessibility should be generalized. INFUSED SOLUTIONS: Sodium bicarbonate does not improve the survival except in particular cases. Physiological serum should be preferred to glucosed serum during reanimation.

[Acute coronary syndromes without ST segment elevation]. / Les syndromes coronariens aigus sans sus-décalage du segment ST.

NEW DENOMINATIONS: With the arrival of new therapeutic strategies requiring rapid intervention, acute coronary syndromes required classification on earlier data than the Q-wave or MB creatinine kinase. In a patient with anginal pain and depending on the electrocardiogram, we now distinguish syndromes with or without ST segment elevation. REGARDING ANTIPLATELET DRUGS: Aspirin is used in all cases, as well as clopidogrel. Anti PG IIb-IIIa agents are set aside only for the forms at risk, when an angioplasty is envisaged in the short term. ANTICOAGULANTS: Enoxaparin has demonstrated its superiority over unfractionated heparin. In general, the biological controls are not indispensables; they can however be used in certain cases (notably elderly patients). OTHER TREATMENTS: These are beta-blockers (first dose via the intravenous route in the case of persisting pain, then relay to the oral route), calcium-channel blockers (diltiazem, verapamil) when beta-blockers are contraindicated, nitrate derivatives with demonstrated antalgic effect but not to be used if an extension to the right ventricle or low blood pressure is suspected, nasal oxygen in the case of cyanosis or respiratory distress, enzyme conversion inhibitors if hypertension persists, and repeated intravenous injections of morphine in the case of persisting intense pain. CORONARY REVASCULARISATION: In all the patients considered at high risk, coronary revascularisation is recommended within the first 24 hours, when technically possible.

[Diagnostic and therapeutic progress. Venous thromboembolism, cardiac insufficiency and radio contrast agents]. / Progrès diagnostiques et thérapeutiques. Maladie veineuse thrombo-embolique, insuffisance cardiaque, produits de contraste.

MODALITIES FOR THE DIAGNOSIS OF VENOUS THROMBOEMBOLISM: Currently rely on the confrontation of the initial clinical data and the results of D-dimer measurements, a venous Doppler, although reliable, is not a first-line exploration. REGARDING TREATMENT: Indications for thrombolysis are currently limited to massive pulmonary oedema with shock. Alteplase added to heparin improves the progression of severe embolism; it spares the patients from heavy interventions of resuscitation but the mortality remains the same. Concerning anticoagulant treatments, prolonged antivitamin K at classical doses is more effective than low doses and for limited duration if phlebitis is an idiopathic one. FOR HEART FAILURE WITH PRESERVED EJECTION FRACTION: Treatment of these heart failures, formerly know as 'diastolic' is similar to that of the acute phase of systolic heart failure. However, care should be taken with vasodilatators. CONCERNING HEART FAILURE IN GENERAL: The brain natriuretic peptide (BNP) represents a remarkable progress for the aetiological diagnosis of dyspnoea (inferior to 80 pg/ml in the case of pulmonary origin, superior to 300 pg/ml in the case of cardiac origin or severe pulmonary embolism). Regarding treatment, for acute heart failure, it is still the association of nitrates and diuretics, with oxygen therapy and eventually inotropics. Beta-blockers, which have revolutionized the treatment of chronic heart failure, must be maintained whenever possible in the case of the onset of acute pulmonary oedema. Multisite pacing is increasingly used in refractory chronic heart failure. Implantable defibrillation has become common practice. Non-invasive ventilation (Bi or C-PAP) is interesting in acute cardiogenic pulmonary oedema. THE PREVENTIVE ROLE OF N ACETYL-CYSTEINE: N acetyl cysteine reduces the incidence of nephropathies induced by the radio contrast products in patients with chronic kidney failure. Combined with hydratation, it must be proposed the day before and on the day of the procedure in any patient with diabetes or kidney failure.

[Acute coronary syndromes with ST-segment elevation]. / Les syndromes coronariens aigus avec sus-décalage du segment ST.

UNBLOCK THE CORONARY ARTERIES: For the treatment of acute coronary syndromes with ST-segment elevation, emergency repermeabilisation is of the artery is crucial, generally by primary angioplasty than by fibrinolysis. The other treatments have little beneficial effects on mortality. Primary angioplasty is the technique of choice when it can be performed in the intensive care units with staff with sufficient experience and within the 90 minutes following the preliminary medical management, and benefiting from the supply of PG IIb-IIIa. THROMBOLYSIS: Performed before the twelfth hour, thrombolysis reduces mortality. The earlier it is performed the greater the benefits. A significant reduction is mortality is observed even in patients aged over 75. The indications for coronography are determined by the existence of clinical risk factors and by the data of supplementary non-invasive examinations (sonography, scintigraphy, effort testing). When clinical risk factors exist from the start, a coronography must be performed. In the absence of initial risks, and if the non-invasive examination reveals risk factors, then a coronarography should be performed.