Models and Analysis of Vocal Emissions for Biomedical Applications

The International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA) came into being in 1999 from the particularly felt need of sharing know-how, objectives and results between areas that until then seemed quite distinct such as bioengineering, medicine and singing. MAVEBA deals with all aspects concerning the study of the human voice with applications ranging from the neonate to the adult and elderly. Over the years the initial issues have grown and spread also in other aspects of research such as occupational voice disorders, neurology, rehabilitation, image and video analysis. MAVEBA takes place every two years always in Firenze, Italy

Application of spontaneous Raman scattering for measurements of thermal non-equilibrium in high-speed mixing and combustion

Mixing-induced vibrational non-equilibrium is studied in the turbulent shear layer between a high-speed jet and a surrounding hot-air coflow. The vibrational and rotational temperatures of N2 and O2 are determined by fitting measured spontaneous Raman scattering spectra to a model that allows for different equilibrium distributions of the vibrational and rotational states. The mixing of the jet fluid with the coflow gases occurs over microsecond time scales, which is sufficiently fast to induce vibrational non-equilibrium in the mixture of hot and cold gases. I measured the non-equilibrium on the hot side of the shear layer, but not on the cold side where the vibrational population in the first hot band is negligible. The effect of fluctuating temperatures on the time-averaged Raman measurement was quantified using single-shot Rayleigh thermometry. The Raman scattering results were found to be insensitive to fluctuations except where the flame is present intermittently. It was also found that the measured non-equilibrium increases in the shear layer when N2 is removed from the jet fluid, indicating that the measurements average two competing processes that occur simultaneously at a molecular scale: vibrationally hot N2 cooled by the fast jet fluid and vibrationally cold jet fluid heated by a hot coflow. An interesting inference is that the averaging effect is always present, regardless of the measurement resolution. No measurable vibrational non-equilibrium is found in the O¬2¬ molecules in the same non-reacting regions. This difference between species temperatures violates the two-temperature assumption often used in the modeling of high-temperature non-equilibrium flow. A new technique was developed to obtain spontaneous Raman scattering temperature measurements from a single laser pulse. This technique required the construction of a multiple-pass cell to obtain adequate scattered signal. Additionally, the pulse was stretched temporally with a system of partial reflectors and time-flight-delay ring cavities in order to reduce the peak power of the 1 J laser pulses. These measurements were found to be in agreement with the previous time-average results and allowed for measurement to be made near the fluctuating base of a lifted flame – a region where time-averaged measurements do not give meaningful results.Aerospace Engineerin

A comparison of two auditory front-end models for horizontal localization of concurrent speakers in adverse acoustic scenarios

Ears are complex instruments which help humans understand what is happening around them. By using two ears, a person can focus his attention on a specific sound source. The first auditory models appeared in literature in the previous century; nowadays, new approaches extend previous findings. Extensive research has been carried out through the years, but many details of the auditory processing remain unclear. In this thesis, two auditory models will be analyzed and compared

Attitude-referenced radiometer study. Volume 2 - Precision radiometric system

Attitude reference radiometer study for earth orbiting spacecraf