Search results for "Decibel"
showing 3 items of 3 documents
Discrimination of early/intermediate and advanced/complicated coronary plaque types by radiofrequency intravascular ultrasound analysis
2002
Radiofrequency intravascular ultrasound (IVUS-RF) analysis, as an extension of conventional IVUS imaging, may provide more accurate plaque discrimination. Thirty-two autopsy atherosclerotic coronary arteries were investigated. Corresponding sectors in different plaques were matched by histologic and RF analysis. Histologic analysis utilized the American Heart Association plaque classification. The backscattered ultrasound RF signal was analyzed by fast-Fourier transform, providing the underlying frequency components of its power spectrum. The normalized backscattered signal power (in decibels [dB]) for frequencies between 15.3 and 40.3 MHz was then measured for plaque discrimination. Advanc…
Noise Levels in an Urban Hospital and Workers' Subjective Responses
1995
Internal noise levels were measured in a 232-point grid that encompassed the main building of a major University Hospital in Valencia, Spain. Most noise equivalent sound levels that were obtained exceeded 55 dBA, and in some instances these sound levels were very high. Hospital workers' subjective responses to noise were evaluated with a self-answered questionnaire. A total of 295 workers volunteered to participate. Their answers revealed that the most important noise sources were located primarily inside the hospital. Noise levels were perceived to be sufficiently high to interfere with their work, and noise levels were also thought to affect patients' comfort and recovery. Most subjects t…
Demo 56. Sensibilidad acústica: curvas isofónicas
2013
Objetivo: Comprender el comportamiento no lineal del oído mediante el experimento de Fletcher y Mundson sobre la sensación sonora.