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EN
This paper presents the results of comparison of vibration reduction levels between standard square based piezo actuators and piezoelectric sensor-actuator hybrids. Modelling was done using FEM method in ANSYS software. Model consisted of a steel plate with piezo elements attached. One of the elements was used as an actuator to excite plate’s vibrations. The other was either a standard homogeneous square based actuator or a sensor actuator hybrid with 2 possible sizes of the sensor part of said hybrid. Harmonic analyses were performed for the 1st, 2nd, 4th and 5th mode shapes with the goal function being the minimalization of displacement vector sum of a number of nodes (there were 3 possible cases). Significant vibration reduction levels were obtained with no significant differences in said levels between standard actuators and sensor-actuator hybrids. Reducing the size of sensor part of sensor-actuator allowed for lower voltages needed to achieve vibration reduction levels.
EN
The development of our civilization and increasing noise pollution are strongly connected. In 2021, the Tatra National Park was visited by a record number of tourists - about 4 million 600 thousand. The previous record was broken in 2018 - then the Polish Tatra Mountains were visited by 3 million 800 thousand. people. The aim of the paper is the analysis of noise pollution and soundscape of the most popular national park in Poland - Tatra National Park. The Koscieliska Valley was selected for the study, because it is the second area in the park in terms of the number of tickets sold according to the statistics kept by the Tatra National Park. The paper presents the results of the analysis of acoustic measurements and ambisonic recordings made during four seasons using classical method and the soundscape method. In addition, psychoacoustic parameters and soundecology indicators such as: loudness, sharpness or roughness, ACI (acoustic complexity index), NDSI (normalized difference soundscape index), BIO (bioacoustic index), ADI (acoustic diversity index), AEI (acoustic evenness index) were calculated.
3
Content available Acoustic Panels Inspired by Nature
EN
The article presents the approach to the design process of acoustic panels based on the scientific research. This approach is based on combining the technical and the design competences to develop the innovative product value for the concept of acoustic panels. The article presents the concepts of two new acoustic panels – an absorbing and scattering panel and a panel reflecting sound waves. The first part of the article presents the starting point for the presented project – the acoustic research and the inspiration for both types of presented solutions. Next, the materials possible to use were discussed, which could reproduce the natural acoustic properties of the lava and glacier caves. The next part presents consecutive stages of the product development in a modern form, ensuring the expected acoustic properties. The last part of the article presents a fully functional solution and proposes further research and development directions.
EN
This paper presents numerical analyses of the impact of the size of the sensor-actuator part on sensor-actuator efficiency. For that purpose, numerical models of a steel plate clamped on all sides were created with two piezoelectric actuators attached to it. One was used to excite the plate and the second (which could be either a standard actuator or a sensor-actuator, having different shapes and sensor part size) to reduce plates vibrations. Harmonic analyses were performed with the goal function being the minimum of the displacement vector sum of n nodes, where n can have different values depending on the case study.
5
Content available remote Vibrotactile amplitude discrimination on the wrist of visually impaired people
EN
Support for spatial orientation and mobility of the blind and partially sighted people is still a hot and unsolved topic. It is well known that in supporting devices non-acoustic communication is recommended due to the role of the sense of hearing in the spatial orientation of the visually impaired people. Knowledge about discriminative ability of touch is crucial when designing devices which use tactile interfaces. The paper presents results of psychophysical studies connected with vibration perception on the wrist of blind and partially sighted people. The presented research examined the ability to identify the changes of amplitude of vibration on the wrist. Research was carried out on students of Special Schools for the Blind and Partially Sighted Children in Krakow. Thirty blind, partially and normal sighted people were examined. Transformed up/down method was used to determine vibrotactile amplitude discrimination threshold. Thresholds were obtained on the ventral wrist at 5 frequencies: 25, 32, 63, 125 and 250 Hz. Results were examined to find factors which could influence the threshold value.
EN
This paper deals with numerical analyses of plates vibration reduction effectiveness of an integrated disc based piezoelectric sensor-actuator compared to standard type disc based piezoelectric actuator. For that purpose 400 x 400 x 2 mm plate clamped on all sides was modelled with 2 piezo elements attached to it. One was a standard square based piezoelectric actuator used to excite the plate. The second one is disc based and can be either a standard element or an integrated sensor-actuator and is used for vibration reduction. The harmonic analyses were performed for the 1st, 2nd, 4th and 5th mode. Voltage used for plates excitation was always set to 100 V. The amplitude of voltage applied to the actuator was selected using internal ANSYS optimization procedures. The goal function for this was the minimum of the displacement vector sum of n nodes of the plate, with n having 3 possible values.
EN
This article shows acoustic measurements from Svalbard archipelago in the Arctic, located in the Arctic Ocean. The aim of the research was to show the Svalbard soundscape as well as to record and analyse the spatial-temporal dynamics of the acoustic environment, the human impact on the soundscape and to collect baseline data for future comparative research. Svalbard is interesting for many science disciplines because it has an arctic climate and, at the same time, it is relatively easily accessible. Climatologists, geologists, glaciologists, biologists and even anthropologists could find interesting themes to investigate here. Additionally, the soundscape of Spitsbergen is worthy of detailed examination. This paper presents comparative analysis of the soundscape of various spots near Longyearbyen in Management Area 10. The soundscape analysis of selected valleys shows the strong influence of human activity on the soundscape as well as the variability and characteristic features of the natural Arctic soundscape.
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