RESUMEN
In this work, a method for measuring tow angles in carbon fiber components, based on the use of a polarized camera, is analyzed from a metrological point of view. Carbon fibers alter the direction of the reflected light's electrical field, so that in each point of the surface of a composite piece, the angle of polarization of reflected light matches the fiber orientation. A statistical analysis of the angle of linear polarization (AoLP) in each pixel of each examined area allows to evaluate the average winding angle. An evaluation of the measurement uncertainty of the method on a cylinder obtained by a filament winding process is carried out, and the result appears adequate for the study of the distribution of angles along the surface of the piece, in order to optimize the process.
RESUMEN
Sensors based on MEMS technology, in particular Inertial Measurement Units (IMUs), when installed on vehicles, provide a real-time full estimation of vehicles' state vector (e.g., position, velocity, yaw angle, angular rate, acceleration), which is required for the planning and control of cars' trajectories, as well as managing the in-car local navigation and positioning tasks. Moreover, data provided by the IMUs, integrated with the data of multiple inputs from other sensing systems (such as Lidar, cameras, and GPS) within the vehicle, and with the surrounding information exchanged in real time (vehicle to vehicle, vehicle to infrastructure, or vehicle to other entities), can be exploited to actualize the full implementation of "smart mobility" on a large scale. On the other hand, "smart mobility" (which is expected to improve road safety, reduce traffic congestion and environmental burden, and enhance the sustainability of mobility as a whole), to be safe and functional on a large scale, should be supported by highly accurate and trustworthy technologies based on precise and reliable sensors and systems. It is known that the accuracy and precision of data supplied by appropriately in-lab-calibrated IMUs (with respect to the primary or secondary standard in order to provide traceability to the International System of Units) allow guaranteeing high quality, reliable information managed by processing systems, since they are reproducible, repeatable, and traceable. In this work, the effective responsiveness and the related precision of digital IMUs, under sinusoidal linear and curvilinear motion conditions at 5 Hz, 10 Hz, and 20 Hz, are investigated on the basis of metrological approaches in laboratory standard conditions only. As a first step, in-lab calibrations allow one to reduce the variables of uncontrolled boundary conditions (e.g., occurring in vehicles in on-site tests) in order to identify the IMUs' sensitivity in a stable and reproducible environment. For this purpose, a new calibration system, based on an oscillating rotating table was developed to reproduce the dynamic conditions of use in the field, and the results are compared with calibration data obtained on linear calibration benches.
RESUMEN
In this paper, a methodology is discussed concerning the measurement of yarn's angle of two different glass-reinforced polypropylene matrix materials, widely used in the production of automotive components. The measurement method is based on a vision system and image processing techniques for edge detection. Measurements of angles enable, if accurate, both useful suggestions for process optimization to be made, and the reliable validation of the simulation results of the thermoplastic process. Therefore, uncertainty evaluation of angle measurement is a mandatory pre-requisite. If the image acquisition and processing is considered, many aspects influence the whole accuracy of the method; the most important have been identified and their effects evaluated with reference to two different materials, which present different optical-type characteristics. The influence of piece geometry has also been taken into account, carrying out measurements on flat sheets and on a semi-spherical object, which is a reference standard shape, to verify the effect of thermoforming and to tune the process parameters. Complete uncertainty in the order of a few degrees has been obtained, which is satisfactory for purposes of simulation validation and consequent process optimization. The uncertainty budget also allowed individuation of the most relevant causes of uncertainty for measurement process improvement.
RESUMEN
BACKGROUND: Pre-hospital triage with ECG-transmission may reduce time to reperfusion in patients with ST-elevation acute myocardial infarction (STEMI). Less, however, is known on potential benefit of ECG-transmission triage in mountain areas, with complex orography. METHODS: Patients admitted for STEMI and primary coronary angioplasty (pPCI) in a mountain area served by a single cathlab and triaged with ECG-transmission were enrolled in the study and compared with controls: patients' demographics and time to coronary wire were recorded. RESULTS: Forty-seven consecutive patients were enrolled in the study: 23 patients following ECG transmission and 24 STEMI patients who presented directly to the Emergency Department. At multivariable regression analysis, pre-hospital ECG-transmission electrocardiogram was an independent predictor of shorter time-to-wire (beta -0.34, pâ¯<â¯0.05). In case of transport times >30â¯min, ECG-transmission triage achieved time-to-wire times 20% shorter. Excluding unreducible transport time, avoidable delay was reduced by 38% in the whole population, by 48% in case of peripheral areas (transport timeâ¯>â¯30â¯min from cathlab) and elderly (>80â¯years) patients (pâ¯<â¯0.05 in all cases). CONCLUSIONS: Pre-hospital triage with ECG-transmission is associated with shorter ischemic time even in mountain areas with a complex orography profile. The benefit is greater in elderly patients and remote areas.
Asunto(s)
Electrocardiografía/instrumentación , Intervención Coronaria Percutánea/normas , Infarto del Miocardio con Elevación del ST/diagnóstico , Anciano , Anciano de 80 o más Años , Electrocardiografía/métodos , Electrocardiografía/estadística & datos numéricos , Servicios Médicos de Urgencia , Femenino , Humanos , Difusión de la Información/métodos , Masculino , Persona de Mediana Edad , Intervención Coronaria Percutánea/estadística & datos numéricos , Infarto del Miocardio con Elevación del ST/fisiopatología , Telemedicina/métodos , Telemedicina/normas , Telemedicina/estadística & datos numéricos , Factores de Tiempo , Triaje/métodos , Triaje/normas , Triaje/estadística & datos numéricosRESUMEN
In this paper, a methodology is described aiming at emphasizing physical and metrological criteria in feature selection for condition monitoring of a real scale mechatronic system. The device is used for packaging applications according to the movements of its end effector, driven by a couple of brushless servomotors and a kinematic mechanical linkage. The approach is hybrid, meaning that the starting feature set is built with reference to both experimental data from different sensors and to the indication of a simplified kinematic and dynamic model of the mechanical linkage itself. A critical comparison and mixing of theoretical and experimental data, based also on a physical interpretation of differences, suggests some more features, with respect to the classical ones, of hybrid type, which could be mostly correlated to the effects of statuses and defects of the system to be identified. The whole procedure is step by step validated, in order to evaluate the variability of features, throughout the whole procedure. The variability is analyzed depending on the actions that are realized in order to define, select, and use the proposed features for data processing by advanced algorithms, like the most typically used classifiers and artificial neural networks. A comparison with the state-of-the-art automatic feature's selection procedure is also presented. Experimental results show that the proposed methodology is able to classify with high accuracy many statuses of the mechatronic system, which are only slightly different as for set-up settings and/or mechanical wear and lubrication conditions of mechanical parts of the mechatronic system. Issues to be pursued to a more effective generalization of the method are also discussed.
RESUMEN
BACKGROUND: Epithelial splenic cysts (ESC) are uncommon lesions of the spleen. The etiopathogenesis of these cysts is controversial, even if Burrig's theory is the most accredited. The histological distinction between epidermoid and mesothelial cysts may be difficult, particularly for monostratified epithelium. PATIENTS AND METHODS: In the period between January 1986 and February 2004, 11 patients with ESC were studied. The history, physical findings, all relevant diagnostic studies and treatment were reviewed. All histological material was reviewed in detail with immunohistochemistry for CEA, CA 19-9, cytokeratin and calretinin. RESULTS: Epidermoid cysts were positive for CEA, CA 19-9, and cytokeratin, but negative for calretinin. Mesothelial cysts were positive for cytokeratin and calretinin, but negative for CEA and CA 19-9. CONCLUSION: Immunohistochemistry allows differential diagnosis between epidermoid and mesothelial cysts. With regard to etiopathogenesis, these data could mean that epidermoid and mesothelial cysts have distinct origins, though at variance with Burrig's theory. Although the ESC in this series were treated by open splenectomy, the recent approach by conservative and laparoscopic techniques offers great promise.