To understand spoken language, the human brain must have fast mechanisms for the representation and identification of speech sounds. Stimulus-induced synchronization of neural activity at gamma frequencies (20-80 Hz), occurring in humans at 200-300 msec from stimulus onset, has been suggested to be a possible mechanism for neural object representation. Auditory and visual stimuli also evoke an ...

Introduction:  The  success  of  hyperthermia  depends  on  the  accuracy  of  the  temperature  monitoring in the tumor and the surrounding normal tissue. In this study, the temperature changes  were determined by computing the speckle displacement in the ultrasound digital images. Speckle  tracking algorithm was used to compute the displacement.  Materials and Methods: The experiment was perf...

Thedensity(ρ) and speed of sound (u)of the binarymixture (diethylene glycol monoethyl ether (carbitol) + propylene glycol (PG)) have been reported at T= (288.15, 298.15, 308.15 and 318.15) K. The excess molar volume ( ) and isentropic compressibility deviation (Δκs) were calculated using the measured data. The obtained values of ( ) and (Δκs) are negative and positive,...

This paper examines a new technique for measuring gas composition through the use of a spirometer. A spirometer is high precision pressure transducer which measures the speed of sound in a gas through the emission and reception of ultrasonic pulses, commonly used in medicine to measure patient lung capacity. The spirometer was successfully calibrated to measure gas composition to an accuracy of...

In this paper, computer simulation of a three-phase synchronous motor drive is described. This drive/system is supplied with a new type of pulse-width modulated voltage source inverter (PWM VSI) whose amplitude of the first harmonic, compared to a conventional sinusoidal PWM VSI, is increased by about 17% and whose amplitude of higher harmonics is also reduced inversely proportional to their or...

workplace factors such as sound must have the minimum impact on the operators of combine harvester, so that they can guide and control many functions of the combine. in this study, some factors affecting the noise generated by two combine harvesters john deere 1055 and sampo 3065 were evaluated. research factors were engine speed, gear ratios, type of operation and microphone distance. the resu...

In this paper, computer simulation of a three-phase synchronous motor drive is described. This drive/system is supplied with a new type of pulse-width modulated voltage source inverter (PWM VSI) whose amplitude of the first harmonic, compared to a conventional sinusoidal PWM VSI, is increased by about 17% and whose amplitude of higher harmonics is also reduced inversely proportional to their or...

It is a deceptively simple question to ask how acoustic disturbances propagate in a non–homogeneous flowing fluid. If the fluid is barotropic and inviscid, and the flow is irrotational (though it may have an arbitrary time dependence), then the equation of motion for the velocity potential describing a sound wave can be put in the (3+ 1)–dimensional form ∆ψ ≡ ∂μ ( √−g g ∂νψ) / √−g = 0. The acou...

In this paper a novel hybrid algorithm for harmonics estimation in power systems is proposed. The estimation of the harmonic components is a nonlinear problem due to the nonlinearity of phase of sinusoids in distorted waveforms. Most researchers implemented nonlinear methods to extract the harmonic parameters. However, nonlinear methods for amplitude estimation increase time of convergence. Hen...

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...