Subject(s)
Air Pollutants, Occupational/adverse effects , Air Pollution, Indoor/adverse effects , Metallurgy , Nitrogen/adverse effects , Occupational Health , Refrigeration , Air Movements , Air Pollution, Indoor/analysis , Air Pollution, Indoor/prevention & control , Asphyxia/chemically induced , Asphyxia/epidemiology , Asphyxia/prevention & control , Equipment Failure , Equipment Failure Analysis , Humans , Hypoxia/chemically induced , Hypoxia/epidemiology , Hypoxia/prevention & control , Metallurgy/methods , Occupational Diseases/chemically induced , Occupational Diseases/epidemiology , Occupational Diseases/prevention & control , Refrigeration/adverse effects , Refrigeration/instrumentation , United States/epidemiologySubject(s)
Halogens/adverse effects , Hazardous Substances/adverse effects , Lighting , Mercury/adverse effects , Occupational Health , Safety Management/methods , Accidents, Occupational/prevention & control , Equipment Failure , Fluorescence , Humans , Lighting/adverse effects , Lighting/instrumentation , United States , United States Environmental Protection AgencySubject(s)
Cumulative Trauma Disorders/prevention & control , Ergonomics/methods , Industry/instrumentation , Occupational Diseases/prevention & control , Occupational Health Nursing/organization & administration , Printing/instrumentation , Body Height , Cumulative Trauma Disorders/etiology , Humans , Male , Middle Aged , Nurse's Role , Occupational Diseases/etiology , Risk Factors , Safety Management , Task Performance and Analysis , WorkloadABSTRACT
Low power, radarlike electromagnetic (EM) wave sensors, operating in a homodyne interferometric mode, are being used to measure tissue motions in the human vocal tract during speech. However, when these and similar sensors are used in front of the laryngeal region during voiced speech, there remains an uncertainty regarding the contributions to the sensor signal from vocal fold movements versus those from pressure induced trachea-wall movements. Several signal-source hypotheses are tested by performing experiments with a subject who had undergone tracheostomy, and who still was able to phonate when her stoma was covered (e.g., with a plastic plate). Laser-doppler motion-measurements of the subject's posterior trachea show small tissue movements, about 15 microns, that do not contribute significantly to signals from presently used EM sensors. However, signals from the anterior wall do contribute. EM sensor and air-pressure measurements, together with 3-D EM wave simulations, show that EM sensors measure movements of the vocal folds very well. The simulations show a surprisingly effective guiding of EM waves across the vocal fold membrane, which, upon glottal opening, are interrupted and reflected. These measurements are important for EM sensor applications to speech signal de-noising, vocoding, speech recognition, and diagnostics.