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Number of results: 6
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Abstract

Steam discharge produces noise due to rapid expansion and a temperature drop of ejected steam. This is why steam silencers are used to change one-stage into multi-stage expansion, which reduces the intensity of pressure and temperature drop during this process and shifts emitted noise into higher frequencies, which are easier to dampen. This paper presents a flow-acoustic numerical model of a steam silencer. It is meant to help to obtain a precise analysis of phenomena occurring in steam silencers and improve the process of designing this type of device. The model described in this paper was based on the parameters of a real working unit manufactured in the Institute of Power Engineering – Thermal Technology Branch. Most of the steam silencers are designed based on construction guidelines that have not been changed for a long time. This restrained an increase in the acoustics efficiency of the steam silencers. An improvement of their flow and acoustic properties allows for the development of smaller, more efficient, and lighter construction. The current version of the model was used for the analysis of flow and acoustic changes which occur after modifying the lower region of a shell of the steam silencer. The proposed modification allowed for a 19% increase in mass flow rate through the silencer and noise reduction in the low-frequency range.
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Bibliography

[1] Karczewski J., Kopania J., Bogusławski G.: Reduction of noise from industrial installations, i.e. steam blow-off silencers. Energetyka Cieplna i Zawodowa 712(2018), 14–19 (in Polish).
[2] Vincent P., Larsonnier F., Rodrigues D., Durand S.: Analytical modeling and characterization of an infrasound generator in the air. Appl. Acoust. 148(2019), 476–483.
[3] Nowicki G., Nowicki T.J., Prystup A., Slusarska B., Chemperek E.: Effects of infrasound generated in urban areas on health of people and animals – an attempt to localize environmental infrasound sources using computer simulations. J. Pre-Clin. Clin. Res. 8(2014), 2, 81–85.
[4] Sorokin L.I.: Calculation and Measurements of the Characteristics of Noise Created in a Far Noise Field by Jet Planes. Mashinostroenie, Moscow 1968 (in Russian).
[5] Klyuevl V.V.: Handbook on the Control of Industrial Noises. Mashinostroenie, Moscow 1979 (in Russian).
[6] Dragun D.K., Perfil’ev Yu.P., Liukevich N.V., Khotulev V.A.: Shaft-Type Launchers. Bauman MGTU, Moscow 2003 .
[7] Lukashchuk V.N.: Noise generated during operations for purging steam superheaters and development of measures to reduce its influence on the environment. PhD thesis, Moscow 1988.
[8] Hockle M., Muller H.A.: A Handbook on Technical Acoustics. Sudostroenie, Leningrad 1980 (in Russian).
[9] Kurlze G.: Physik und Technik der Lermbergdampfung. G. Brann Buchverlag, Karlsruhe 1963 (in German).
[10] Middelberg J.M., Barber T.J., Leong S.S., Byrne K.P., Leonardi E.: Computational fluid dynamics analysis of the acoustic performance of various simple expansion chamber mufflers. In: Proc. Acoustics 2004, Gold Coast, 3-5 Now. 2004.
[11] Hu X., Zhou Y., Fang J., Man X., Zhao Z.: Computational fluid dynamics research on pressure loss of cross-flow perforated muffler. Chin. J. Mech. Eng. 20(2007), 2, 88–93 (English Edn.).
[12] Tupov V.B., Taratorin A.A.: The choice of turbulence models for steam jet. Procedia Engineer. Dynamic and Vibroacoustics of Machines (DVM2016) 176(2017), 199–206.
[13] Taratorin A.A., Tupov V.B.: Detection techniques of acoustical centre of noise source, Therm. Eng. 62(2015), 7, 480–483.
[14] Journal of Laws of the Republic of Poland (Dziennik Ustaw Rzeczypospolitej Polskiej), Item 2288, Attachment 7, 21/11/2019.
[15] Mohanty A.R, Pattnaik S.P.: An Optimal Design Methodology for a Family of Perforated Mufflers. SAE Tech. Pap. 2005-26-053, 2005.
[16] Zheng S., Kamg Z.X., Lian X.M.: Acoustic Matching Simulation of Muffler with Hybrid Approach. SAE Tech. Pap. 2011-01-1516, 2011.
[17] Comsol Multiphysics 5.6 Release Highlights. https://www.comsol.com/release/5.6 (acessed 24 March 2021).

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Authors and Affiliations

Patryk Gaj
1
Krzysztof Sobczak
2
Joanna Kopania
3
Kamil Wójciak
1

  1. Institute of Power Engineering, Mory 8, 01-330 Warsaw, Poland
  2. Lodz University of Technology, Wólczanska 219, 90-924 Lodz, Poland
  3. Lodz University of Technology, Piotrkowska 266, 90-924 Lodz, Poland
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Abstract

The stance of mysticism on language is located in the field of tensions between the fundamental inability to express the essence of God through the medium of language and the imperative, or the need, to talk about it. In the space betwixt and between, there extends mystic silence as a paradoxical, but effective way of communication and insight. Depending on individual mystics, whose selection from the Middle Ages to the Baroque is presented in the text, silence receives also various additional aspects.

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Authors and Affiliations

Cezary Lipiński
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Abstract

‘Return to nature’ has become a buzzword in both scientific and public discourse. The growing interest in this phenomenon calls for the development of reliable tools for scientific research, for example the adaptation of various connectivity to nature (CN) scales developed by researchers from other cultural circles and other countries. The purpose of this study is to evaluate the psychometric properties of a Polish version of the AIMES scale for multidimensional assessment of CN as conceptualized by Ives et al. (2018). Validation studies were conducted using a survey administered on Prolific, an online platform, with a sample of 516 Poles (56% of them women) aged 18-66. The Polish version of AIMES showed high internal consistency (α = .92). Confirmatory factor analysis confirmed that the scale structure consists of a unified second-order factor with five first-order factors: attachment, identity, materialism, experiential, and spiritual. Relevance analysis showed significant positive associations of CN with perception of nature and silence, pro- environmental attitude and behaviour, psychological well-being, gratitude/awe, forgiveness, spirituality, extraversion, conscientiousness, and agreeableness, and a marginal positive association with openness to experience. The results strengthen the psychometric qualities of the AIMES scale, indicating its applicability to the study of CN in Polish contexts.
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Authors and Affiliations

Janusz Surzykiewicz
1 2
ORCID: ORCID
Sebastian Binyamin Skalski-Bednarz
1 3
ORCID: ORCID
Loren L Toussaint
4
ORCID: ORCID
Łukasz Kwadrans
5
ORCID: ORCID
Anna Kwiatkowska
6
ORCID: ORCID
Karol Konaszewski
7
ORCID: ORCID

  1. Catholic University of Eichstätt-Ingolstadt, Eichstätt, Germany
  2. Cardinal Stefan Wyszyński University in Warsaw, Warsaw, Poland
  3. University of Economics and Human Sciences in Warsaw, Warsaw, Poland
  4. Luther College, Department of Psychology, Decorah, IA, USA
  5. University of Silesia in Katowice, Institute of Pedagogy, Katowice, Poland
  6. Polish Academy of Sciences, Institute of Psychology, Warsaw, Poland
  7. University of Białystok, Faculty of Education, Białystok, Poland
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Abstract

This paper proposes an active noise control (ANC) application to attenuate siren noise for the patient lying inside ambulance with no sound proofing. From the point of cost effectiveness, a local ANC system based on feedforward scheme is considered. Further, to handle the limitation of limited Zone of Silence (ZoS), the ANC based on virtual sensing is explored. The simulations are done in MATLAB for the recorded ambulance siren noise signal. The results indicate that ANC can be an effective solution for creating a silent environment for the patient.
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Authors and Affiliations

Sharma Manoj Kumar
Vig Renu
Pal Ravi
Shantharam Veena

Authors and Affiliations

Agnieszka Ozga
1
Jacek Wierzbicki
1
Dominik Mleczko
1

  1. Faculty of Mechanical Engineering and Robotics, Department of Mechanics and Vibroacoustics, AGH University of Krakow, Kraków, Poland
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Abstract

Jonas Hassen Khemiri, born in 1978, is one of the most interesting contemporary Swedish and European writers with a Tunisian immigrant background. His second novel Montecore: en unik tiger ( Montecore: The Silence of the Tiger), published in 2006, has got an epistolary form deducted from the exchange of letters between Kadir and Jonas. However, the main character of the novel is Abbas Khemiri – the disappearing, estranged father of Jonas – a figure close to the real writer. Khemiri’s book has got an innovative linguistic form and contains many erudite references to the phenomena of popular culture. It is also a complex portrayal of the different generations of (mainly Arab-based) immigrant and post-immigrant communities in Sweden coupled with a nuanced look on bright and dark sides of the Swedish state, model of identity and integration. This material is enriched by the examples taken from Khemiri’s novel Everything I Don’t Remember and short story As You Would Have Told It To Me (Sort Of) If We Had Known Each Other Before You Died.

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Authors and Affiliations

Michał Moch
ORCID: ORCID

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