Background: Normal Eustachian tube function is one of the important factor required for successful tympanoplasty outcome. A clinically useful test for assessment of Eustachian tube function is still lacking. Aims And Objectives: To evaluate Eustachian tube function by impedance audiometry and compare the outcome of surgery with respect to graft take up in normal and abnormal Eustachian tube fun...

In impedance control for force tracking, it is well known that the reference trajectory of the robot is calculated from known environmental stiffness. The authors present a simple technique for determining the reference trajectory under the condition that the environment is unknown. The technique is developed based on the replacement of the unknown stiffness with a function of the measured forc...

Multichannel intraluminal impedance (MII) is a new technique for evaluation of bolus transport. We evaluated esophageal function using bolus transport time (BTT) and contraction wave velocity (CWV) of liquid, semisolid, and solid boluses. Ten healthy subjects underwent MII swallow evaluation with various boluses of sterile water (pH 5), applesauce, three different sized marshmallows, and iced a...

A novel beam-based method for measuring the longitudinal impedance spectrum is demonstrated using experimental data from the PEP-II High Energy Ring (HER). The method uses a digital longitudinal feedback system from which the charge and synchronous phase are measured for every bucket. Calculation of the transfer function from ll shape to synchronous phase yields the impedance seen by the beam a...

We evaluated impedance pharyngography (IPG), a new method to assess swallowing function based on changes in the electrical impedance of the neck during swallowing. The electrical impedance of the neck, recorded by the 4-electrode method, changed with the equivalent cross-sectional area of the route of the electric current due to reflex activities of related organs during swallowing. IPG wavefor...

Thoracic impedance is modulated by events within the respiratory cycle, which represents a source of "noise" in impedance cardiography. Respiration itself, however, is a physiological rhythm of interest to psychophysiologists. We report here methods and validation for deriving impedance pneumographic measures of respiration from impedance cardiography signals, based on standard tetrapolar band ...

The measurement of the electrical impedance inside the esophagus provides information about its status, and is being explored in the study of the gastroesophageal reflux. This paper presents theoretical computation of impedance inside the esophagus. The results of the numerical solution for a simple geometry are compared against the solution formulated from the Green's function approach. The ef...

This paper presents a model of sound propagation in a duct, for the purpose of active noise control. A physical model generally different from those explored in much of the literature is derived, with non-constant acoustic load impedance at the one end, and a coupled disturbance loudspeaker model at the other end. Experimental results are presented which validate the derived transfer function. ...

In this paper, we consider the Dirichlet and impedance boundary value problems for the Helmholtz equation in a non-locally perturbed half-plane. These boundary value problems arise in a study of timeharmonic acoustic scattering of an incident eld by a sound-soft, in nite rough surface where the total eld vanishes (the Dirichlet problem) or by an in nite, impedance rough surface where the total ...

The electromechanical (E/M) impedance method is a powerful technique in active structural health monitoring (SHM). E/M impedance method utilizes as its main apparatus an impedance analyzer that reads the in-situ E/M impedance of piezoelectric wafer active sensors (PWAS) attached to the monitored structure. Present-day impedance analyzer equipments (e.g.HP4194) are bulky, heavy and expensive lab...