http://hdl.handle.net/2117/3448 2013-06-19T16:25:00Z http://hdl.handle.net/2117/19448 Title: Ultrasonic inspection system for powder metallurgy parts Authors: Turó Peroy, Antonio; Chávez Domínguez, Juan Antonio; García Hernández, Miguel J.; Bulkai, András; Tomek, Péter; Tóth, Gabor; Gironés, Ana; Salazar Soler, Jorge Abstract: The demand for powder metallurgy (P/M) parts in its traditional automotive market is predicted to grow, but future sector expansion depends directly upon its capability to manufacture zero-defect parts for industries such as aerospace and medicine. The lack of adequate inspection systems has important implications from the point of view of quality assurance, since it increases the costs, time and wasted material. In recent years the applicability of several techniques for the inspection of P/M parts has been investigated, such as Eddy current testing, computer tomography or X-ray imaging, but studies have revealed that all of them have deficiencies that make them unavailable for a complete and reliable flaw detection and density defect recognition. A new inspection tool has been developed based on pulse echo ultrasonic technology combined with robotics, which makes it possible to provide a global density map of sintered. 2013-05-29T17:39:54Z http://hdl.handle.net/2117/16170 Title: Process design involving ultrasound Authors: Salazar Soler, Jorge; Turó Peroy, Antonio; Chávez Domínguez, Juan Antonio; García Hernández, Miguel J. 2012-07-04T15:01:35Z http://hdl.handle.net/2117/14036 Title: Implementación y primeros resultados de la asignatura de introducción a la ingeniería en los nuevos grados de la ETSETB-UPC Authors: Sayrol Clols, Elisa; Onrubia, Raúl; García Hernández, Miguel J.; Oliveras Vergés, Albert; Bragós Bardia, Ramon; Pegueroles Vallés, Josep R.; Alarcón Cot, Eduardo José; Camps Carmona, Adriano José; Sardà Ferrer, Joan; Consolación Segura, Carolina María; Mussons Sellés, Jaume; Pons Peregort, Olga Abstract: En este trabajo se describe la asignatura "Introducción a la Ingeniería de las TIC" que, basándose en restricciones y especificaciones iniciales, ha sido concebida, diseñada e implementada en la ETSETB de la UPC. Es la primera de una serie de cuatro asignaturas de proyectos distribuidas a lo largo de los grados. Está organizada en tres itinerarios paralelos que cubren la visión de sistema TIC complejo, los conceptos básicos de economía, empresa y gestión de proyectos y la realización física de un proyecto. En los primeros 5 años este proyecto se lleva a cabo sobre la plataforma SeaPerch, un pequeño robot subacuático desarrollado en el MIT Sea Grant, sobre el que se diseñan y construyen sistemas de medida y comunicaciones. Después de probarla con grupos pequeños durante dos cuatrimestres, se acomete su explotación con una previsión de 250 estudiantes en el cuatrimestre de primavera de este año. 2011-11-23T16:22:17Z http://hdl.handle.net/2117/11421 Title: Análisis y diseño de un oscilador en banda V Authors: Salazar Soler, Jorge; Corbella Sanahuja, Ignasi Abstract: In this paper the analysis and design of an oscillator in V ban is presented. Taking advantage of a coaxial oscillation, some results related with frequency stability have been obtained. A special attention has been paid in the design of the RF choke 2011-02-17T12:50:41Z http://hdl.handle.net/2117/10985 Title: Laser interferometric measurements of air-coupled lamb waves Authors: García Rodríguez, Mercedes; Yañez, Y.; García Hernández, Miguel J.; Salazar Soler, Jorge; Turó Peroy, Antonio; Chávez Domínguez, Juan Antonio Abstract: In this paper, experimental measurements of the vibration pattern that results when an air-coupled A0 Lamb wave mode propagates in a plate are presented. Lamb waves are generated using an air-coupled piezoelectric transducer array. The measurements were performed in 304 stainless steel using laser interferometry. Air coupled piezoelectric ultrasonic array transducers are a novel tool that could lead to interesting advances in the area of non-contact laminar material testing using Lamb wave’s propagation techniques, and it is interesting to know the vibration pattern in the plate. Using this system, some snapshots of the interaction of the A0 Lamb wave mode with a crack-defect in the plate are also presented. 2011-01-12T12:40:50Z http://hdl.handle.net/2117/10984 Title: High voltage pulser for NDE air-coupled lamb wave ultrasonic system Authors: García Rodríguez, Mercedes; Arjones, V.; Yañez, Y.; García Hernández, Miguel J.; Salazar Soler, Jorge; Turó Peroy, Antonio; Chávez Domínguez, Juan Antonio Abstract: This paper describes a high voltage pulser developed for an air-coupled ultrasonic array NDE system based on Lamb waves. Unlike the classical single pulse excitation circuits, this pulser is able to generate a bipolar return-to-zero square-wave burst signal up to ±250 V of amplitude. The system is composed of two 32 elements concave array with a resonant frequency of 800 kHz. To excite all the transducers an array of pulsers with small volume and weight to be able to place it close to the concave array has been designed. 2011-01-12T12:32:05Z http://hdl.handle.net/2117/10982 Title: Guided wave sensing in a carbon steel pipe using a laser vibrometer system Authors: Ruiz Toledo, Abelardo; Salazar Soler, Jorge; Chávez Domínguez, Juan Antonio; García Hernández, Miguel J.; Turó Peroy, Antonio Abstract: Non-Destructive Evaluation (NDE) techniques have achieved a great development during the last decades as a valuable tool for material characterization, manufacturing control and structural integrity tests. Among these tools, the guided wave technology has been rapidly extended because it reduces inspection time and costs compared to the ordinary point by point testing in large structures, as well as because of the possibility of inspecting under insulation and coating conditions. This fast development has motivated the creation of several inspection and material characterization systems including different technologies which can be combined with this technique. Different measurements systems based on laser techniques have been presented in order to inspect pipes, plates and diverse structures. Many of them are experimental systems of high cost and complexity which combine the employment of a laser for generation of waves in the structure and an interferometer for detection. Some of them employ air-coupled ultrasound generation transducers, with high losses in air and which demand high energy for exciting waves in materials of high stiffness. The combined employment of a commercial vibrometer system for Lamb wave sensing in plates has been successfully shown in the literature. In this paper we present a measurement system based on the combined employment of a piezoelectric wedge transducer and a laser vibrometer to sense guided acoustic waves in carbon steel pipes. The measurement system here presented is mainly compounded of an angular wedge transducer, employed to generate the guided wave and a commercial laser vibrometer used in the detection process. The wedge transducer is excited by means of a signal function generator whose output signal has been amplified with a power signal amplifier. A high precision positioning system is employed to place the laser beam at different points through the pipe surface. The signal detected by the laser vibrometer system is amplified with a signal amplifier and then it is displayed in a digital storage oscilloscope. This set-up offers the possibility of analyzing in a simpler way the wave propagation and the material evaluation in pipes of certain wall thickness. The material characterization considering distinct wave propagation modes can be easily achieved, changing the different incident angles of the wedge piezoelectric probe and their combined employment with several driving signals. Moreover, this experimental sensing system offers other possibilities of inspecting and analyzing the wave propagation in some features (bends, flange joints, welds,...) of the pipe surface which cause very large reflections and mode conversions and which in practice limits the inspection range when are inspected with conventional receiving transducer arrangements. 2011-01-12T12:11:12Z http://hdl.handle.net/2117/10968 Title: Análisis de masas alimenticias mediante sensores electrónicos de ultrasonido: aplicación al estudio de masas de cereales Authors: García Álvarez, Javier; Gomez, M.; Rosell, C. M.; Turó Peroy, Antonio; Chávez Domínguez, Juan Antonio; García Hernández, Miguel J.; Salazar Soler, Jorge 2011-01-11T19:14:55Z http://hdl.handle.net/2117/10518 Title: Adaptación de una asignatura de electronica digital a la semipresencialidad y al Espacio Europeo de Educación Superior Authors: Bermejo Broto, Sandra; Chávez Domínguez, Juan Antonio; Domínguez Pumar, Manuel; Pons Nin, Joan Abstract: Este trabajo describe y analiza la evolución del formato semipresencial de la asignatura Sistemas Digitales 1, inicialmente impartida dentro de una titulación de segundo ciclo y actualmente adaptada al EEES e impartida dentro de Master de Ingeniería Electrónica de la Escuela Superior de Ingeniería de Telecomunicación de Barcelona de la Universidad Politécnica de Catalunya. Del estudio de distintos indicadores de calidad y rendimiento se concluye que el formato semipresencial es una alternativa excelente al presencial. Este primero aporta flexibilidad y permite la posibilidad, entre otras, de cursar una doble titulación. Los resultados de la evaluación demuestran que esta flexibilidad no va en detrimento de la calidad y la eficiencia del proceso de aprendizaje. 2010-12-10T09:49:21Z http://hdl.handle.net/2117/8074 Title: Técnicas de ultrasonidos aplicadas al reconocimiento "in situ" de discontinuidades visibles en soleras de hormigón armado Authors: Zamora i Mestre, Joan-Lluís; García Hernández, Miguel J. 2010-07-08T11:26:10Z