Papers by Keyword: Acoustic Measurement

Abstract: Classroom speech intelligibility has become one of the main concerns in schools and other learning institutions development nowadays. This is because the qualities of student’s perceptions towards teacher are essentials in learning development. Measures have been introduced by the acoustical association to tackle the speech intelligibility problems in the classroom such as room renovations. Room’s acoustics standards have been introduced in several countries but still the questions on whether the standards fits on every classroom in different countries are still arise. Studies have also shown that most of the researches that have been conducted were only focusing on the conventional type classroom which depends only on the teacher’s vocal power. This paper will formulate the measurement protocol on measuring the speech intelligibility in the sound reinforced (multiple speaker) classroom. Finally it was found that the speech intelligibility in the sound reinforced classroom is better than the conventional classroom by using Linear Discriminant Analysis.

Abstract: Tire puncture is the main factor for traffic accidents, especially for the expressway traffic accidents. In this paper, the voice signal is used to distinguish the abnormal conditions of the car tires. which can identify the tire fault signal, timely find tire abnormal condition and send out warning information. It can ensure the safe driving. Experiments show that the system can monitor the tire effective working state.

Abstract: Acoustic thermometry method is used to measure two-dimensional temperature distribution of a circular boundary temperature field experimentally. The measured temperature field is compared with a point-by-point temperature measurement, the results shows that the acoustic method is consistent with the point-by-point measurement which proves that it is reliable to use this method to measure the two-dimensional temperature distribution.

Abstract: This paper briefly described borehole wave velocity test and the principle and method of wave velocity test technique, by using acoustic measurement and control technology of tunnel rock mass test, integrality index of rock mass is obtained, ultimately, we evaluate the rock mass integrity. The actual application effect is good and provides an important basis for the engineering rock mass quality evaluation.

Abstract: Simulation analysis and experiment research are performed on the aeroacoustic noise of a landing gear component in this paper. Detached Eddy Simulation (DES) is used to produce the flow field of the model. The Ffowcs-Williams/Hawkings (FW-H) equation is used to calculate the acoustic field. The sound field radiated from the model is measured in the acoustic wind tunnel. A comparison shows that the simulation results agree well with the experiment results under the acoustic far field condition. The results show that the noise radiated from the model is broadband noise. The directivity of the noise source is like a type of dipole. The wheel is the largest contributor and the strut is the least contributor to the landing gear noise. The results can provide some reference for low noise landing gear design.

Abstract: Simulation analysis and experiment research are performed on the aeroacoustic noise of a landing gear component in this paper. Detached Eddy Simulation (DES) is used to produce the flow field of the model. The Ffowcs-Williams/Hawkings (FW-H) equation is used to calculate the acoustic field. The sound field radiated from the model is measured in the acoustic wind tunnel. A comparison shows that the simulation results agree well with the experiment results under the acoustic far field condition. The results show that the noise radiated from the model is broadband noise. The directivity of the noise source is like a type of dipole. The location between shock absorber and strut, shock absorber and bogie can induce the interaction noise which is presented by two energy peaks in the spectra. The shock absorber and the bogie is the main contributor while the strut is the least contributor to the total noise.

Abstract: This paper briefly introduces the use of sound-absorbing materials and sound-proof materials in the buildings, concisely summarizes the factors taken into account in the acoustic design, and then introduces the requirements of architectural acoustics materials in sports venues. It ultimately introduces the general requirements for acoustic measurement. Therefore, we can draw some conclusions. On the one hand, it is necessary to strengthen basic research, technical measures and organizational management practices in acoustic materials. On the other hand, we should pay more attention to transmission channels and reception conditions. At last, it is necessary to establish cooperation with various professions for comprehensive study, with a view to obtaining the best technical performance and economic benefits.

Abstract: Due to increased product requirements, usual conditions for materials cannot be applied anymore. To reduce energy consumption, lightweight constructions are demanded but they cannot stand necessary mechanical stress. Therefore, local reinforced elements are applied for instance. According to actual research in material sciences, it is prerequisite to verify the position of this strengthening. Various physical principles can be used for non-destructive testing of this effect. In this article, an approach based on acoustic signals is presented. On the one hand a strategy could be to do comparative studies between nominal and sample and on the other to predetermine the place just by acoustic parameters like eigenmodes. In preliminary test, vibration characteristics of these innovative materials (e.g. bake-hardening plate and sandwich structure) are determined and reveal capabilities for acoustic methodologies. So, this approach could be a promising tool to localize reinforced elements.