نتایج جستجو برای: ultrasonic parameters
تعداد نتایج: 604637 فیلتر نتایج به سال:
Matching pursuit is an iterative method whereby a signal is decomposed into a linear combination of functions that are selected from a redundant dictionary. In the original paper by Mallat and Zhang [1], a dictionary of Gabor functions is proposed. Each Gabor function is the product of a Gaussian function with a complex sinusoid, and is specified by time, frequency and scale. Since these functi...
There are several techniques that may be used in the tomographic imaging of structural and geotechnical systems. X-ray tomography and ultrasonic imaging are two of the extreme techniques as functions of resolution and costs. On one hand, X-ray tomography allows the collection of high-resolution images in small specimens that may be removed from the structure. The application of X-rays in the fi...
AIMS The aim of this clinical trial was to compare clinical and biochemical healing outcomes following ultrasonic mechanical instrumentation versus ultrasonic mechanical instrumentation associated with topical subgingival application of amino acids and sodium hyaluronate gel. METHODS Eleven systemically healthy subjects with moderate-severe chronic periodontitis, who had four sites with pocke...
To achieve a precise noninvasive temperature estimation, inside patient tissues, would open promising research fields, because its clinic results would provide early-diagnosis tools. In fact, detecting changes of thermal origin in ultrasonic echo spectra could be useful as an early complementary indicator of infections, inflammations, or cancer. But the effective clinic applications to diagnosi...
Ultrafiltration (UF) of whey is a major membrane based process in the dairy industry. However, commercialization of this application has been limited by membrane fouling, which has a detrimental influence on the permeation rate. There are a number of different chemical and physical cleaning methods currently used for cleaning a fouled membrane. It has been suggested that the cleaning frequency ...
High resolution ultrasonic imaging requires high frequency wide band ultrasonic transducers, which produce short pulses and highly focused beam. However, currently the frequency of ultrasonic transducers is limited to below 100 MHz, mainly because of the challenge in precise control of fabrication parameters. This paper reports the design, fabrication, and characterization of sensitive broadban...
There are many techniques available to study physical properties to interpret the molecular interaction in liquids, liquid mixtures and solutions. The study of ultrasonic waves through solution is found to be quite interesting. The study of ultrasonic waves through solution is used for knowing the nature and strength of intermolecular forces and their interaction in liquids, liquid mixtures and...
Most ultrasonic systems employing guided waves for flaw detection require information such as dispersion curves, transducer locations, and expected propagation loss. Degraded system performance may result if assumed parameter values do not accurately reflect the actual environment. By characterizing the propagating environment in situ at the time of test, potentially erroneous a priori estimate...
Ultrasonic characterization of porous silicon using a genetic algorithm to solve the inverse problem
This paper presents a method for ultrasonic characterization of porous silicon in which a genetic algorithm based optimization is used to solve the inverse problem. A one dimensional model describing wave propagation through a water immersed sample is used in order to compute transmission spectra. Then, a water immersion wide bandwidth measurement is performed using insertion/substitutionmethod...
conclusions the present research demonstrated that the ultrasonic (us) process can be utilized as an effective and simple method for treatment of mg dye in an aqueous solution. moreover, the eeo is directly proportional to the mg concentration and power density and inversely proportional to temperature and mechanical agitation, which can be predicted by the obtained empirical kinetics model. co...
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