Our publications

• Acoustics Course for Industry

  XVIII International Symposium on News in Audio and Video Technology, Wrocław 2020

  Marcin Łuczak, Karolina Jaruszewska, prof. Andrzej Dobrucki

  Protection from noise and provision of the comfort of life and work for society is presently one of the most significant challenges of our civilization. Noise is one of the most widely and most frequently experienced problems in the industrial working environment. The idea of implementing new e-learning and teaching methods originated from the need to enhance practical industrial acoustic knowledge. The main purpose of the courseware is to innovatively fill the gap in recent VET education programs and to increase specialists’ awareness about the role acoustic comfort plays in the life of human beings.

  Acoustics Course for Industry (ACI) consists of few modules: Noise, Impact of noise on humans, Environmental and occupational noise, and Noise management. Educational materials include case studies, sound samples, interactive content, and VR-360 videos. Effects can be watched on a computer or using the VR headset. Results of this project constitute an example of synergy between initiatives undertaken in research and innovation as well as promoting to use of new technologies to transfer scientific and engineering knowledge.

   

  ACI

• Acoucou Platform to Acquire Professional Skills and Knowledge in the Field of Acoustics

  23rd International Congress on Acoustics, Aachen 2019

  Karolina Jaruszewska; Filip Barański; Magdalena Piotrowska; Manuel Melon; Oliver Dazel; Michael Vorländer; Lukas Aspöck; Marko Horvat; Kristian Jambrošic; Monika Rychtáriková; Leopold Kritly; Andreas Herweg.

  Today, in the digital era, education must meet the needs and adapt to modern forms of knowledge transfer.
  While this is often implemented in higher education programs (distance learning, OpenCourseWare platforms), vocational education and training seems to be the most traditional branch of education, especially in the field of specialized courses for engineers. Our goal is to create space for new, innovative and multidisciplinary approaches for teaching and e-learning acoustics (e.g., based on gamification, VR, or web simulators).

  The ACOUCOU Platform (http://acoucou.org/) is a part of a strategy aimed at expanding and strengthening acoustic knowledge, supporting the development of innovative teaching methods based on attractive and effective delivery of content, services, teaching methodologies and practices at national and international levels. The form of materials and courses published on the Acoustic Courseware Platform are suitable to be used for self-learning as well as in blended learning, where an educator uses materials from platform to carry out training among employees/students. Technical, professional knowledge is usually presented as text including equations and technical drawings. Presenting it in a visually attractive form is more appealing and increases the motivation of the users. The visualization of phenomena simplifies the understanding of problems and makes it easy to acquire knowledge in similar, practical situations of an engineer’s work.

  ACOUCOU

  Poster

• The Effect of the Weld Type on Ensemble Average in SEA

  23rd International Congress on Acoustics, Aachen 2019

  Paweł Nieradka, Sebastian Szarapow

  Statistical energy analysis (SEA) predicts the average response of a population. This population consists of similar vibroacoustic structures subjected to white noise forces at high frequencies. However, usually in engineering applications, the SEA method is used to determine the response of a particular structure. It results from the assumption, that in the case of complex structures the response of a single member from the population will not significantly differ from the average.

  The aim of the research was to check the above assumption on a simple structures. Six similar mechanical structures were tested. Each structure consisted of two plates welded together at right angles. The vibration (velocity) level reduction between the plates was determined. From the point of view of the SEA, each of the six L-shaped structures is represented by the same SEA system composed of two 2D subsystems connected by line junction. However, the resulting line junctions have been achieved by two different welding techniques. This detail is omitted during SEA calculations. Vibration reduction obtained on a single structure was compared with ensemble average covering the entire six-element sample. The influence of the weld type on transmission was considered. The obtained results were compared with the SEA prediction.

  https://www.researchgate.net/publication/335813371_The_Effect_of_the_Weld_Type_on_Ensemble_Average_in_SEA

• Environmental Acoustics - What, For what and Why?

  Noisy Exchange PWR, 2019

  Tomasz Malec

  The presentation is an introduction to the topic of Environmental Acoustics and provides exhaustive description of issues related to the topic. Is starts from presenting a broad view on the sources of sound and proceeds with detailed explanation of topics such as: environmental acoustics’ research areas, basic principles, targets for acoustic analysis, identification methods and selection of solutions. The closing part of the presentation shows the connections between Environmental Acoustics and other fields of knowledge and it’s applications.

  http://www.noisyexchange.pwr.edu.pl/wp-content/uploads/2019/10/Environmental-acoustic-what-for-what-and-why-Tomasz-Malec.pdf

• Insertion Loss of Enclosures with Lined Slits

  Euronoise 2018, Heraklion, Crete

  Paweł Nieradka, Andrzej Dobrucki

  An air slit with one of the boundaries created by an absorbing lining is an acoustic system that can introduce the transmission loss (TL) of high values, especially in the high range. The aim of this paper is evaluation of overall insertion loss (IL) in acoustic enclosures caused by air slits. For this purpose, two MDF sound insulating enclosures with dierent sizes were constructed. Enclosures were elevated in order to create slits with adjustable height. Because enclosures were acoustically adapted, an absorbing boundary was naturally created. Mechel’s model was utilized to predict TL of that kind of absorbing slits. The insertion losses of both enclosures were measured according to ISO 11546-1. Next, simulation of insertion loss has been performed (two models have been used: a well-known simple formula and a SEA model). It was noticed that the diference between results obtained with using simple formula and with SEA model is negligible, because a transmission across slits (modelled in SEA as an non-resonant transmission) is much higher than a transmission across enclosure walls in a wide frequency range.

  Results of simulations and measurements have been compared. A good agreement occurs in a case of narrow slits. Furthermore, results confirmed the importance of providing high modal overlap conditions while using statistical models in acoustic simulation.

  https://www.researchgate.net/publication/325540701_Insertion_loss_of_enclosures_with_lined_slits

• Strategic Partnership in the Field of Acoustics

  6th Conference on Building Physics and Applied Technology in Architecture and Building, Leuven 2018

  Karolina Jaruszewska, Christ Glorieux, Vojtech Chmelik, Daniel Urban, Kristian Jambrosic, Monika Rychtarikova

  The aim of the Strategic Partnership is to connect entities from various sectors and disciplines to create business and scientific partnership oriented to the development and promotion of education, training, and reseach in the field of acoustics. Result of partnership work is a creative space for teaching and e-learning acoustics (ACOUCOU). The construction of trainings let engineers not only work independently and bring their skills in acoustics to perfection, but also it delivers a modern tools for constant professional improvement of teachers, trainers and educational mentors at a workspace.

  The large project partnership with many institutional presences has a significant impact at the European level, accelerating effective cooperation and improvement in the fields of acoustics.

   

  Strategic Partnership

• Comparison of Low Frequency Signals emitted by Wind Turbines of Two Different Generator Types

  International Conference Energy, Environment and Material Systems (EEMS 2017), Polanica-Zdrój

  Tomasz Malec, Tomasz Boczar, Daria Wotzka and Paweł Frącz

  The paper presents results of comparative analysis of infrasound noise generated by wind turbines of two types: asynchronous type REPOWER MM92 with power equal to 2 MW and synchronous type Vensys 62 with power equal to 1.2 MW. Frequency spectra of sound pressure levels generated during operation by both turbines for exemplary chosen wind speed values are depicted. Within the shown spectra the resonant frequencies have been indicated, for which sound pressure variations over time are shown. Based on the achieved frequency spectra it was stated that in general the asynchronous type turbine produces lower pressure levels, which are less stable over time, and indicates higher pressure values around the resonant frequencies as compared to the synchronous type turbine. Also it was stated that the asynchronous type turbine is more influenced by the wind conditions and generates higher pressure values by higher wind speeds then the synchronous type turbine.

  The main contribution of this paper lies in indication that the type of wind turbine generator has significant impact on the level of infrasound noise emitted to the environment.

  https://www.e3s-conferences.org/articles/e3sconf/abs/2017/07/e3sconf_eems2017_01001/e3sconf_eems2017_01001.html

   

  article EEMS 2017

• Good Wind for Regions - Experts about Wind Energy

  POLISH WIND ENERGY ASSOCIATION, 2016

  Tomasz Malec

  In the publication, Dr. Eng. Tomasz Malec (Head of the KFB Acoustic Department) wrote the chapter about the assessment of the impact of noise generated by wind turbines on the environment.

   

  Dobry wiatr dla regionów - Eksperci o energetyce wiatrowej

• Measurements and Analysis of Infrasound Noise emitted by High Power Wind Turbine

  Faculty of Electrical Engineering, Automatic Control and Informatics, Opole University of Technology, 2016

  On 14 January 2016, at the Faculty of Electrical Engineering, Automatic Control and Informatics at the Opole University of Technology, a public defense of the doctoral dissertation of Tomasz Malec (Head of the Department of Acoustics KFB) took place in the discipline of Electrical Engineering. The subject of the dissertation was: “Measurements and analysis of infrasound noise emitted by high power wind turbine”.

  As part of the work, measurements of wind turbines were performed. Then, a multi-variant analysis of acoustic signals generated by high-power wind turbines operating in real conditions was carried out. The infrasound signals, low frequency signals, and audible signals were analyzed. The influence of a number of parameters and external factors on the obtained measurement results was also examined. For the tested representative high-power wind turbines, no excessive levels of sound pressure levels were found, regardless of wind speed, meteorological conditions, design solutions, operating time, rated power value and the amount of electric power delivered to the power system.

  Get file

• Reduction of Occupational Noise Exposure for Metalworking Workstations

  Noise Control 2016, Gniew, Poland

  Bartosz Chmielewski

  Metalworking using hand-held pneumatic tools are the cause of exceedances of permitted noise levels at the workplace. In these operations exposure is caused by emission of noise from the tool itself and the noise generated by the contact of the tool with the workpiece.
  The methodology of the acoustic analysis leading to the development of the acoustic guidelines, concept, design and implementation of solutions was discussed in general. This paper presents a prototype solution built by a KFB Poland team. Conceptual design,
  calculations and results of acoustic measurements of effectiveness of the solution were presented.

  Reduction of Occupational Noise Exposure

• ArAc - Multibook of Architectural Acoustics

  6th International Building Physics Conference, IBPC 2015, Torino

  Karolina Jaruszewska, Monika Rychtarikova, Thomas Wulfrank, Joanna Jablonska, Magdaelna Boeck

  ArAc- Multibook of Architectural Acoustics (an interactive publication) is a didactic tool, whose main objective is to innovatively fill the gap in technical literature and to increase architects’ awareness about the role acoustic comfort plays in the life of human beings. The ArAc project demonstrates an innovative approach to education and professional development of architects in the area of acoustics. Professional books on architectural acoustics are aimed chiefly at readers with mathematical or technical background, usually graduates of electronics or physics faculties. Such studies have only a limited usefulness to architects, who intend not to study architectural acoustics as a separate area of knowledge, but to search for an inspiration regarding acoustically correct architectural solutions. The materials included in the multibook are to help architects in correct and unassisted solving of common and unsophisticated noise protection and interior acoustics problems. This type of knowledge is most useful in conceptual design works related to architectural acoustics, as well as in mutual understanding of different priorities that architects and acoustician working together may have.

  ArAc-Multibook of Architectural Acoustics is a four-language application for mobile devices (tablets, smartphones both for iOS and Android) and on website. The Multibook is the first application of this kind in the form of a acoustics manual for architects enriched with audio, image galleries, animations, instructional videos and elements of interactive infographics.

  ArAc - Multibook of Architectural Acoustics

• Evaluation of Influence of Work Analysis Data on Determination of Occupational Noise Exposure...

  InterNoise 2013, Innsbruck

  Bartosz Chmielewski, Filip Barański

  Evaluation of Influence of Work Analysis Data on Determination of Occupational Noise Exposure for Fitter–Welder Workstation

  In article authors present results of determination of occupational noise exposure (performed in accordance with standard PN-EN ISO 9612:2011) for fitter–welder working in one of manufacturing plant in Poland. The main objective was to verify the measurement results contained in two earlier reports of other laboratories, who obtained noise indicators by measurements using task-based method (strategy 1). The results varied considerably, despite the lack of change in the production cycle for the workstation. To verify that issue, an additional measurement session with full-day measurement (strategy 3) was performed, extended by highly detailed recording of work activities (tasks, operations with tools, events) and their duration. Emphasis was placed on matter of determination and identification of tasks. Finally, for both strategies, the comparison of the contribution from each identified task to daily noise exposure level was
  made. The equivalent sound level values (total and octave bands) was obtained for each identified operation.

  Analysis of collected results led to evaluation of influence of work analysis data on determination of occupational noise indicators. The authors point out that, apart from the issue of noise exposure, significant differences in periodic measurements do not allow employers to monitor the effectiveness of anti-noise solutions, but in most cases, employers require from acoustic companies warranty on the effectiveness of the proposed acoustic solutions.

  Internoise 2013

• A New Method for the Acoustic Analysis of Noise Sources in Industry Halls

  EURONOISE 2012, Prague

  Karolina Jaruszewska, Filip Barański

  The paper describes the method for the acoustic analysis of noise sources in industry halls using new measurement technologies. Measurements were carried out by an acoustic camera (system using beamforming method) and 3D laser used for scanning closed-spaces geometry. The purpose of these measurements is to locate and identify noise sources on a production line in a complicated acoustic situation (reverberation conditions, many and various noise sources).

  The results of these measurements are used as an input in computer simulations with software for noise prediction which leads to creation of noise sources ranking and finding possibilities to reduce the noise level. The measurements show the potential of new measurement technologies of faster and more precise acoustic analysis of noise sources in industry halls.

   

  Euronoise 2012

• Workstation Design in Industrial Halls with Many Noise Sources Using Acoustic Modeling...

  Proceedings of the 12th European Conference on Noise Control EURONOISE 2012, Prague

  Bartosz Chmielewski, Filip Barański

  Workstation Design in Industrial Halls with Many Noise Sources Using Acoustic Modeling and Substitute Sources

  This paper presentsthe authors’ approach for acoustic modelling of component production hall where lots of hand-held tools and machinery are used. The goal is both to create an acoustic map and to determine average daily noise levels at workstations. In order to optimize calculations, substitute sources for each production station were created and the interrelations between the geometry of source-workersystem and the average noise levels for workers of the station were defined. The detailed approach would require the simulation for each specific setup of sources and employees. The proposed approach allows to reduce the number of sources in the model and
  allows to consider only one setup. This paper compares the results of detailed simulations and simulations using the presented methodology. Paper presents the potential of this method and possible applications.

  Workstation design

• Studies on Infrasound Noise emitted by Wind Turbines of Large Power

  ACTA PHYSICA POLONICA A, No.5, Vol. 122 (2012)

  Tomasz Boczar, Tomasz Malec and Daria Wotzka
  Faculty of Electrical Engineering, Automatic Control and Computer Science, Opole University of Technology

  The subject area of this article applies to study of infrasound signals generated by the work of modern wind turbines. Infrasound noise measurements were conducted in accordance with assumptions of the EN 61400-11 standard. The object of study was a newly commissioned wind farm with a total electrical power equal to 30 MW. The considered power station consisted of 15 new wind turbines, each with a capacity of 2 MW. Scope of the analysis performed included designation of time runs, depicting temporal changes, and designation of frequency spectra of the recorded infrasound signals. Evaluation of the impact of changes in wind speed was made.

  Moreover, the scope of analysis, performed in this field, concerned assessment of the impact on the obtained results values of meteorological parameters related to the applied measurement system. Values obtained from measurements were related to and compared with the limits specified in standards and regulations existing in this field.

   

  Infrasound Noise Emitted by Wind Turbines of Large Power (1)

• Analysis of Vibro-Acoustic Signals Generated during Operation of Micro Wind Turbines

  ACTA PHYSICA POLONICA A, No.3, Vol 124 (2013)

  Daria Wotzka, Tomasz Boczar, Tomasz Malec and Radosław Pierzga
  Faculty of Electrical Engineering, Automatic Control and Informatics, Opole University of Technology

  Results of a measurement and analysis of vibro-acoustic signals generated by two low power vertical-axis wind turbines that are installed on the roof of the Electric Power Institute at Opole University of Technology are presented in the paper. The study considers a Darrieus and a Savonius type wind turbines of rated power 1 kW each. For registration of the vibrations of the turbine mast three uniaxial accelerometers and a measurement equipment from Brüel & Kjær were applied.

  The measurement setup is presented in the paper. A comparative analysis of the registered data in the time and time-frequency domains was performed. Results depict changes in the recorded signals in time and frequency under different meteorological conditions, i.e. for different wind speed values. Based on the achieved results significant differences in the mast vibrations of the two kinds of wind turbines were stated.

   

  Analysis of Vibro-Acoustic Signals Generated

• Microphone column

  XIV International Symposium on Engineering and Sound Engineering ISSET 2011, Wrocław

  Bartosz Chmielewski

  The work is an analysis of properties and design methodology of a microphone column as a microphone system with specific directivity characteristics, which could be useful in sound systems for lecture and seminar rooms. The article presents results of a computer simulation run by the author in MATLAB program. Based on these results, characteristics of the microphone column were determined as we as relationships useful in designing a microphone column.

  Microphone column