The present work evaluates the application of artificial neural networks for pattern recognition of ultrasonic signals using pulse-echo and TOFD (Time of Flight Diffraction) techniques in weld beads. In this study pattern classifiers are implemented by artificial neural network of backpropagation type using MATLAB. The ultrasonic signals acquired from pulse-echo and TOFD were introduced, separ...

Among the ultrasound based NDT methods and techniques, some are used for materials characterization. In a typical situation, some of the measurable properties of a tested object’s material are used as a data set for characterization. The basis of measurements are properties of an ultrasonic pulse that can propagate through the object. In order to obtain intense enough registered ultrasonic puls...

OBJECTIVES The objective of this study was to evaluate the efficacy of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation in different energy outputs versus ultrasonic in gutta-percha removal during the endodontic retreatment. MATERIALS AND METHODS A total of 21 extracted human lower premolars were divided into three groups (n = 7). Following the standardized preparation of the r...

The recently developed laser-induced phonon spectroscopy (LIPS) technique is applied to the determination of dynamic mechanical properties of aligned dilauroylphosphatidylcholine (DLPC) multibilayer arrays containing 2 and 20% water by weight. Sample excitation by two crossed 100-ps laser pulses generates a longitudinal ultrasonic wave whose wavelength depends on the crossing angle. In these ex...

Increasing number of ultrasonic applications reflects the potential of this method. As broader is the range of areas involved in ultrasonic measurement, the more essential becomes the question of a universal concept of the equipment for generating and acquiring the ultrasonic data. Ideas and problems met here we would like to share in this publication. The ultrasonic non-destructive evaluation ...

Failures detection in composite laminates is complicated respect to conventional non-destructive testings for metal structures, due their sensibility echoes drown noise depending by the different properties of constituent materials and multi-layered composites structures. The latter, particular, are sensitive impact damage also a low-energy can results severe loss load capacity as result delami...

The conventional ultrasonic imaging techniques including the holographic one give a high resolution in angle, but a relatively poor resolution in range, because the resolution in range is obtained only by use of selective focus or parallax useful only with a small focal ratio. This paper presents the principle and some experimental results of new ultrasonic imaging techniques that use a linear ...

Four different composite mixtures with varying amounts of expanded vermiculite were exposed to high temperatures of 300, 600, 900 and 1100uC for 6 h. Physical and mechanical properties including unit weight, porosity, water absorption, residual compressive strength, residual splitting tensile strength and also ultrasonic pulse velocity were determined after air cooling. Microstructures were inv...

Solid burnt brick sized 290 × 140 × 65 mm or 303 × 145 × 70 mm respectively, represents one of most widespread brick building material, both structural and nonbearing ones, in Czech historical buildings. During their rebuilding and reconstruction, we frequently ask for brickwork material strength. Most exact method is to take test samples just from the construction and put them to trial neverth...