In parallel to the ultrasonic noise assessment procedures and research activity in the field there have appeared several papers in the domain of so called high-frequency audiometry which covers the range of frequencies 8-20 kHz. They are important for recognizing the harmfulness and hazard of the audible high frequency sound components in the same range as the one of the low frequency ultrasonic noise. On the other hand there exists a certain inconsequent situation in the general approach to the problem of ultrasonic noise hazard assessment in work places environment which concerns the convention to include the frequency range of 10-20 kHz to the domain of ultrasonics. The range consists of one third octave bands of central frequencies: 10, 12.5, 16, 20 kHz and conventionally is called low frequency ultrasonic noise though at least the components of the two lowest bands are naturally audible by a majority of population (mainly young people).The paper presents a discussion related to some achievements of the two domains and some conclusions which could be useful for a more consequent description of the subject and could be taken into account in the future regulations for the ultrasonic noise assessment in work places environment.
The hazard assessment of ultrasonic noise impact on human body at workplaces presents an open problem; it is not satisfactorily solved comparing the fund of knowledge and standard regulations established for the case of audible noise. Some research carried on in the Central Institute of Labour Protection - National Research Institute, Poland, are essential for elaboration reliable procedures for the assessment of ultrasonic noise hazard and they have to bring to modernization and creation the corresponding standards in this field. In the presentation, some problems related to measurement procedures applied as well as to the interpretation of results essential for hazard assessment of ultrasonic noise impact on human body will be considered; in particular such cases where some procedures elaborated for audible noise assessment are being transferred to apply in the ultrasonic range without taking fully into account some specific aspects of the high frequency components of the noise.
The International Congress on Ultrasonics'2011 held in Gda?sk, Poland was the third one (after Viena'2007, Austria and Santiago'2009, Chile) over the world meeting of the ultrasonics community, continuing a long tradition of Ultrasonics International Conferences (organized every second year since 1963 to 2005), as well as World Congresses on Ultrasonics (organized every second year since 1995 to 2005). Last 6 years experience of foundation of ICU congresses have shown a real progress in global integration process of the ultrasonics community and provided an excellent platform for the professional knowledge, exchange among scientists and engineers from academic and industrial centers as well as from other institutions and places of ultrasonics studies and applications. Ultrasonics as multi-disciplinary field covers a great number of topics from fundamental physical aspects through chemical, biological, medical, material inspections and others branches to many applications. All contributions of topics of the field of ultrasonics were presented during the ICU'2011 in Gdańsk, and the meeting provided a valuable and unique opportunity for participants to exchange their achievements and experience as well as to enlarge their international contacts on the field.
The Committee on Acoustics of the Polish Academy of Sciences was founded in 1964 by the reso lution of the General Assembly of the Polish Academy of Sciences, within its Division of Engineering Sci ences (Division 4). The idea of creating the Committee was brought up by Professor Ignacy Malecki, a distinguished scientist, an academic teacher, and an internationally acclaimed authority on acoustics.