Alessandro Bellina

University of Illinois, Urbana-Champaign, Urbana, Illinois, United States

Are you Alessandro Bellina?

Claim your profile

Publications (3)3.29 Total impact

  • Hearing Research - HEAR RES. 01/2010; 263:248-248.
  • Jared McNew, Alessandro Bellina, William D O'Brien
    [Show abstract] [Hide abstract]
    ABSTRACT: Flight deck crews are subject to high intensity sounds for prolonged periods of time. Even while using current hearing protection devices such as ear plugs, ear muffs, and helmets, hearing loss is still possible. It is likely that this hearing loss is due to the cochlear stimulation through pathways other than the usual air conduction pathways. In order to develop new hearing protection devices to prevent hearing loss due to these nonair conduction pathways, ray tracing from the full wave equation solution is being used to determine and visualize these dominant pathways. Numerical techniques for performing ray tracing are presented along with the validation of the method by comparing with Snell's law. For small changes in sound speed, angle of transmission errors are less than 20%. As the frequency of the incident pulse is increased, these errors are reduced as would be expected. Results of ray tracing performed on simulation data from two concentric fluid spheres as an approximation to the human head are also presented. Using this model, an insertion loss of 26 dB is observed. [Work supported by AFOSR FA9550-06-0128.].
    The Journal of the Acoustical Society of America 11/2008; 124(4):2456. · 1.65 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The influence of static force on bone conduction threshold measurement behavioral bone conduction thresholds are evaluated in clinical settings using a standard headband. The standard headband is designed to apply 5.4 N of static force to the oscillator (ANSI S3.6-1996 R2004), but in practice the static force varies with head size over a range of several Newtons. The influence of the varied force on behavioral thresholds is uncertain. These thresholds have clinical utility in determining the type and severity of hearing loss and research utility in modeling bone-conducted sound pathways. Behavioral bone conduction thresholds for a group of normal-hearing young adult listeners (ages 18-30) were obtained in 1-dB steps as a function of several force levels (2 N, 5 N, variable force) using custom-calibrated and standard headbands for mastoid and forehead oscillator placements across a frequency range from 250 to 8 kHz in sixth-octave bands. No significant differences in behavioral thresholds were obtained as a function of the static force levels tested, although the results supported previous findings that bone conduction thresholds are more sensitive for mastoid than forehead placement. The impact of static force levels on performance for speech understanding with bone conduction listening systems requires further study. [Work supported by AFOSR FA9550-06-0128.].
    The Journal of the Acoustical Society of America 11/2008; 124(4):2456. · 1.65 Impact Factor