نتایج جستجو برای: ultrasonic focusing
تعداد نتایج: 125732 فیلتر نتایج به سال:
Jumper's knee is a common cause of anterior knee pain among athletes and active populations. Numerous treatments have been described with variable results. To better delineate this, the authors reviewed all articles from 2000 to 2014 pertaining to the treatment of patellar tendinopathy, focusing namely on treatment of recalcitrant cases. Open and arthroscopic techniques were found to achieve si...
Friction stir welding (FSW) is a recently developed solid-state joining process that uses a specially shaped rotating tool to produce lap or butt joints. At the National Research Council, an inter-institute collaboration was started in 2007 with the goal of exploiting the NDE expertise and applying it for the characterization of friction stir welds for various industrial applications. In partic...
Ultrasonic testing and evaluation procedures typically depend on reference reflectors to establish detection sensitivity and evaluation of test data. Rules and regulations governing safety-related components emphasize on test procedures that assure the detectability of discontinuities at all over the component and oriented in any arbitrary direction. Existing procedures, however, do not provide...
Most frequently applied ultrasonic inspection techniques measure the reflectivity of geometric scatterers that are caused by impurities, flaws and defects in the material. Based on the echo sounder principles, the reflector has to be insonified by directed sound pulses. This requires a large number of transducers with different incident angles and sound field patterns, which are more and more r...
Modeling and experimental results of an ultrasonic aperiodic flat lens for use in air are presented. Predictive modeling of the lens is performed using a hybrid genetic-greedy algorithm constrained to a linear structure. The optimized design parameters are used to fabricate a lens. A method combining a fiber-disk arrangement and scanning laser vibrometer measurements is developed to characteriz...
Acoustic lenses are employed in a variety of applications, from biomedical imaging and surgery to defense systems and damage detection in materials. Focused acoustic signals, for example, enable ultrasonic transducers to image the interior of the human body. Currently however the performance of acoustic devices is limited by their linear operational envelope, which implies relatively inaccurate...
development of ultrasound technique has not been progressing for evaluating the internal quality of fruits as fast as that of processed foods. in this research for quality assessment of pear fruit (shah miveh variety) an ultrasonic measurement system was constructed to transmit and receive the ultrasonic waves. the apparatus included a pulser-receiver, a pair of 75 khz ultrasonic transducers wi...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید