Contents of issue 1, vol. 30 (2005)

  1. Professor Robert Christopher Chivers, In Memoriam, Archives of Acoustics, 30, 1, 3-4
  2. M. Kordus, A. Sęk, J. Kociński, Binaural masking of amplitude modulation, Archives of Acoustics, 30, 1, 5-17
  3. E. Walerian, R. Janczur, M. Czechowicz, Noise level spread in the vicinity of a crossroads, Archives of Acoustics, 30, 1, 19-55
  4. M. Meissner, The response of a Helmholtz resonator to external excitation. Part II: Flow-induced resonance, Archives of Acoustics, 30, 1, 57-71
  5. L. Björnö, Contemporary aspects of the theory and application of nonlinear acoustics, Archives of Acoustics, 30, 1, 73-85
  6. D. Bochenek, Z. Surowiak, S.V. Gavrilyachenko, M.F. Kupriyanov, Multicomponent ceramic materials on the basis of PZT for the production of piezoelectric resonators, Archives of Acoustics, 30, 1, 87-107
  7. K. Szemela, W.P. Rdzanek Jr., W. Rdzanek, The acoustic power radiated by a circular membrane excited for vibration both by means of the edge and by external surface load, Archives of Acoustics, 30, 1, 109-119
  8. P. Ranachowski, Z. Ranachowski, F. Rejmund, J. Stankiewicz, Acoustic examination of epoxy-glass insulator material, Archives of Acoustics, 30, 1, 121-130
  9. Chronicle, 34-th Winter School on Wave and Quantum Acoustics, Archives of Acoustics, 30, 1, 131-142
In Memoriam: Professor Robert Christopher Chivers
Professor Robert Christopher Chivers

Professor Robert C. Chivers, a long-standing Associate Editor of the ARCHIVES OF ACOUSTICS and a former English Editor of the ACUSTICA journal passed away at home on 25-th November 2004.
Graduate from Exeter College, Oxford, he first completed his BA (1969) and MA (1973) in Natural Philosophy - Physics. He then continued his research at the University of London, Institute of Cancer Research, where he was awarded PhD in Radiation Biology, 1973. In the same year he received PhD of the University of London. From 1973 to 1996 Robert Chivers was a member of the academic staff at the University of Surrey where he obtained Readership in 1993. Prof. Robert Chivers was outstanding scientist and fantastic academic teacher. He received a commendation in the UK 1992 Partnership Awards for the use of the Socratic method for science teaching.
Prof. Chiver's scientific interests focused on a wide range of acoustic research, particularly this concerning the interaction of ultrasonic waves with inhomogeneous media materials and its practical application in medicine and industry. He concentrated on various types of materials including biological tissue, sea-bed sediments, composites polycrystalline materials, and wood. He developed new, experimental methods for investigation of the fields radiated by ultrasonic transducers. For his work prof. Chivers was granted the RWB Stephens Medal of the Institute of Acoustics in 1997. Prof. Chivers was awarded 13 patents and published almost 270 papers.
He supervised 13 Ph D students, and facilitated completion of several doctorates from abroad, particularly those written in Poland at Gdańsk University of Technology.
Despite the numerous national, and international prestige scientific stands and positions he was one of the establishers and then long-standing Consulting Editor of the Polish scientific quarterly ARCHIVES OF ACOUSTICS,
For over thirty years - since his first encounter with prof. Zenon Jagodziński and Andrzej Stepnowski from Gdańsk University of Technology during 7-th International Congress on Acoustics in 1974 in London - he manifested his great interest and friendliness towards Poland.
He visited our country many times and got many friends in Gdańsk, Warszawa, Gliwice, Kraków and elsewhere. Moreover, he was also very generous host and "cicerone" of tens of Poles visiting United Kingdom thorough 40 years.
For his work and deserts Professor Chivers was granted the Medal of Merit (2001) and the Jubilee Medal (2004) from Gdańsk University of Technology. He was also awarded by Westerplatte Medal of the Polish Naval Academy.
Prof. R. Chivers was also an initiator of awarding an honorary degree of "doctor honoris causa" of the University of Surrey to prof. Zenon Jagodziński in 1996.
The measure of prof. R. Chivers friendliness and interest to our country and its contemporary history was his enormous success in reaching almost perfect Command of Polish language.
We will always remember Bob Chivers as a great friend of Poland and Poles, as an outstanding scientist, as a colleague deeply committed to his work, and as a very generous, noble and amiable human being of fascinating personality.

prof. Andrzej Stepnowski
prof. Roman Salamon
prof. Henryk Lasota
Editorial Board of Archives of Acoustics

M. Kordus, A. Sęk, J. Kociński, Binaural masking of amplitude modulation
Institute of Acoustics, Adam Mickiewicz University
Umultowska 85, 60-614 Poznań, Poland
(received February 17, 2004; accepter October 26, 2004)
A new concept concerned with the transformation of acoustic stimuli in the auditory system postulates the existence of a form of spectral analysis applied to the amplitude changes of the stimuli. It is assumed that this analysis takes place in the so-called modulation filters, i.e. bandpass linear filters tuned to different rates of the amplitude changes. The most striking argument supporting this idea is an effect of masking in the amplitude modulation domain whose nature can be easily explained basing on this concept. As the modulation filters are situated on the higher levels of the auditory system, it is also assumed that this form of masking is entirely a central process. However, most of the studies concerned with masking in the modulation domain used monaural listening only. Therefore, the main purpose of the presented here experiments was to investigate whether this type of masking is entirely a central process.
Using a Three-Alternative Forced-Choice (3AFC) procedure the binaural and monaural masked thresholds of amplitude modulation were determined. A sinusoidal carrier at a frequency of 4 kHz was amplitude modulated by a specially designed band of noise characterized by a very low value of the crest factor, which was used as a masking signals. Different bandwidths of the modulating masking signals were used as well as different center frequencies to investigate whether the masking patterns in the modulation domain depend on the masker bandwidth and its center frequency. The modulating target (masked) signal was a pure tone at a frequency range from 2 to 256 Hz. Both modulating signals were applied to the same sinusoidal carrier signal.
The most effective masking was noticed when the rate of the sinusoidal modulation was close to the center frequency of the masking signal or when it was in its spectral range and decreased outside of this range. The character of this dependence confirms the existence of some form of a frequency selectivity in the modulation rate domain similarly to the audible frequency domain. The thresholds for monaural and binaural listening were very close to each other. This implies that masking in the modulation domain is a central process.
Key words: masking, masking in the modulation domain, modulation filterbank.

E. Walerian, R. Janczur, M. Czechowicz, Noise level spread in the vicinity of a crossroads
Institute of Fundamental Technological Research
Polish Academy of Sciences
Świętokrzyska 21, 00-049 Warszawa, Poland
(received October 30, 2003; accepter September 23, 2004)
In the paper, the PROP10 program is used to present the time-average sound level on façades of buildings in the vicinity of a crossroads. The propagation model within an urban system forming canyon streets includes the wave interaction with obstacles, multi-reflections from building walls and single and double diffraction at their wedges. For the current purpose the program is provided with a road model in which the vehicle route is divided into sub-segments with lengths and linear densities of emitted energy that depend on the traffic organization in the vicinity of the crossroads. The lengths of the sub-segments, where vehicles wait and are forced to a subsequent start and stop, depend on the flow rates on lanes, the equivalent vehicle length, the red and green light times and the speed of leaving a crossroads. The linear energy density at these sub-segments depends on a parameter characterizing the energy emitted during the starting of a vehicle. The time-average sound level is analyzed as a function of the enumerated parameters.
Key words: traffic noise, interrupted movement, canyon street.

M. Meissner, The response of a Helmholtz resonator to external excitation. Part II: Flow-induced resonance
Institute of Fundamental Technological Research
Polish Academy of Sciences
Świętokrzyska 21, 00-049 Warszawa, Poland
(received May 24, 2004; accepter September 23, 2004)
In the paper a phenomenon of sound production in a resonator driven by an air jet has been investigated. Measurements of sound spectra at the closed end of the resonator cavity were performed to determine the influence of the jet velocity on the frequency and amplitude of excited acoustic oscillations. It was found that in the sound generation process two ranges of the jet velocity could be distinguished where different variations of the oscillation frequency with the growing jet velocity were observed. After the onset of oscillation the frequency increased fast with growing jet velocity and the frequency increment was directly proportional to a value of jet velocity. At higher flow velocities an increase in the frequency was still observed, but the frequency growth was much smaller. The experiment has shown also that due to an excitation of mechanical vibrations of the resonator elements a rapid change in the oscillation frequency occurred. Finally, the experimental data were compared to calculation results to examine the accuracy of the theoretical model, in which a force driving the resonator was predicted from the vortex sound theory and the resonator was modelled by an equivalent impedance circuit.
Key words: sound generation, flow-induced resonance, acoustic resonators.

L. Björnö, Contemporary aspects of the theory and application of nonlinear acoustics
UltraTech Holding
Stendiget 19, DK-2630 Taastrup, Denmark
(received October 1, 2004; accepter December 20, 2004)
The foundations of nonlinear acoustics may be traced nearly 250 years back in time, but only the last 50 years have shown an increasing number of attempts to exploit the research results in nonlinear acoustics. Based upon the fundamental equations of fluid dynamics, the second-order acoustic equations may be derived which can be reduced to a compound equation describing several of the most important and fast developing areas of research in nonlinear acoustics. The relations between this compound equation and Burgers' equation, Korteweg-DeVries equation, the K-Z-K equation, Westervelt's equation and the general second-order wave equation are discussed in depth. Finally, it is shown how the derivatives of the compound equation can be applied to nonlinear acoustic research related to materials characterisation by use of the B/A-ratio, to underwater acoustics by use of the parametric acoustic array and to focused, high-power ultrasonic fields.
Key words: nonlinear acoustics, absorption, diffraction, dispersion, focused fields, underwater applications, second-order nonlinearity parameter.

D. Bochenek*, Z. Surowiak*, S.V. Gavrilyachenko**, M.F. Kupriyanov**, Multicomponent ceramic materials on the basis of PZT for the production of piezoelectric resonators
* University of Silesia, Department of Materials Sciences
Śnieżna 2, 41-200 Sosnowiec, Poland
** Rostov State University, Faculty of Physics
Zorge St. 5, 344-104 Rostov-on-Don, Russia
(received December 30, 2003; accepter October 26, 2004)
Investigations on the influence of the PbTiO3 content on the crystalline and domain structure of PZT-based four-component solid solutions have been performed. It has been shown that there is a close relation between the structure and temperature stability of the resonance frequency (fr) of the fabricated piezoceramic transducers. Better and more stable results have been obtained by doping and modifying the basic chemical composition obtaining Pb(Zr1-xTix)O3.
The compositions with minimal Δfr/fr, within the temperature range T=213-358K (in relation to room temperature Tr=293K), exhibited (i) the smallest internal friction (Qm-1), (ii) the highest mechanical quality (Qm), (iii) high values of spontaneous deformation of the elementary cell (δT and δRe), (iv) the complex a-c-domain structure in the tetragonal phase (T) and the simple domain structure in the rhombohedral phase (Re).
The practical result of the present work was the fabrication of piezoceramic electric band filters exhibiting Δfr/fr<0.2% and a high mechanical quality factor (Qm=3225).
Key words: PZT, piezoelectric transducers, resonance frequency, thermal stability.

K. Szemela, W.P. Rdzanek Jr., W. Rdzanek, The acoustic power radiated by a circular membrane excited for vibration both by means of the edge and by external surface load
University of Rzeszów
Rejtana 16a, 35-310 Rzeszów, Poland
(received April 6, 2004; accepter October 26, 2004)
In this paper the acoustic power of the circular membrane, excited both by the edge and external exciting forces uniformly distributed over the whole surface, is examined. Some different amplitudes of exciting factors and some differences between the phases of excitations were considered. It has been assumed that the source of a sound is located in a flat, rigid and infinite baffle and is sourrounded by a lossless and homogeneous fluid medium. The vibrations are axisymmetric and time-harmonic. Employing the Cauchy's theorem of residues and asymptotic formulae for the Bessel functions, the asymptotes for active and reactive power consisting of elementary functions are obtained. The acoustic power radiated by the membrane was shown graphically in terms of the parameters describing both kinds of excitations.
Key words: acoustic radiation power, vibrations of a spherical membrane, excitation produced by edge and surface loads, amplitude-phase effects.

P. Ranachowski*, Z. Ranachowski*, F. Rejmund*, J. Stankiewicz**, Acoustic examination of epoxy-glass insulator material
* Institute of Fundamental Technological Research
Polish Academy of Sciences
Świętokrzyska 21, 00-049 Warszawa, Poland
** Electrotechnical Institute, Division of Electrotechnology and Materials Science
Skłodowskiej-Curie 55/61, 50-369 Wrocław, Poland
(received March 2, 2004; accepter September 23, 2004)
Ultrasonic, microscopic and acoustic emission (AE) methods were applied to investigate the microstructure of composite rods, used as a carrying element of the medium voltage insulators. Such features of material structure as homogeneity level and the appearance of defects were discussed. The research was aimed at determining the influence of the technology of epoxy-glass fabrication on quality parameters of the insulator rods. The results of acoustic testing were compared with the effects of microscopic investigation.
Key words: composite insulator, epoxy-glass material, nondestructive ultrasonic measurements, acoustic emission.

Chronicle, 34-th Winter School on Wave and Quantum Acoustics
Gliwice-Ustroń, 28-th February - 4-th March 2005
The conference is a forum of all fields of acoustics where the wave and quantum ideas are already used or could be used in the future. In particular, it concerns the following issues: quantum acoustics, molecular acoustics, acoustooptics, photoacoustics, solid state acoustics, and similar problems (in brief: widely comprehended as physical acoustics). During the conference theoretical, experimental and technical (applied) works are presented. The works still in progress, not fully finished, are often reported.
As usual, the conference lectures are presented within the framework of the following groups: molecular acoustics, Brillouin and Raman scattering, acoustooptics, magnetoacoustics, acoustoelectronics, acoustic emission, acoustic fields, surface acoustic waves, ultrasound materials, sensors, photoacoustics, photothermics, and the like. As new lectures concerning other issues are delivered, other thematic groups may be formed.
Traditionally, the languages of the conference are Polish and English.
In order to encourage more people to participate in our School, we have decided to extend its workshops offer. The Winter Workshop on Photoacoustics and Photothermics will be conducted for the 10-th time. However, we are glad to invite you to participate in Winter Workshop on Molecular and Quantum Acoustics and in Winter Workshop on Acoustoelectronics and Optoelectronics for the 1-st time. As these problems were traditionally presented on previous occasions, their formation into workshops seems to be natural. Participants can take part in a single workshop or in the whole School.