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Number of results: 5
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Abstract

The specific working conditions of the wind turbine in strong wind cause a number of problems in the measurement of noise indicators used in its short and long-term assessment. The wind is a natural working environment of the turbine, but it also affects the measurement system, moreover, it can be a secondary source of other sounds that interfere with the measurement. One of the effective methods of eliminating the direct impact of wind on the measurement system is placing the microphone on the measurement board at ground level. However, the obtained result can not be directly compared with the admissible values, as it has to be converted to a result at a height of 4 m. The results of previous studies show that this relation depends, inter alia, on the speed and direction of the wind. The paper contains the results of measurements on the measurement board, according to EN 61400-11:2013, and at a height of 4 m above ground made simultaneously in three points around the 2 MW turbine at various instantaneous speeds and changing wind directions. Analysis of the impact of measuring point location on the measurement result of noise indicators and the occurrence of additional features affecting the relationship between the values measured on the board and at the height of 4 m, and especially the tonality, amplitude modulation and content of low frequency content, was m

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Authors and Affiliations

Tadeusz Wszołek
Paweł Pawlik
Dominik Mleczko
Jagna Chronowska
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Abstract

Richard B. Brand, twórca podręcznika Etyka. Zagadnienia etyki normatywnej i metaetyki, oraz Richard M. Hare, autor książki Myślenie moralne: jego płaszczyzny, metody i istota, w swoich dziełach nawiązali dyskusję, która wniosła istotne argumenty do debaty nad zagadnieniem relatywizmu etycznego. Brandt analizuje dwie trudności, z którymi mierzy się Hare. Pierwsza dotyczy akceptacji niewolnictwa na gruncie utylitaryzmu. Według Brandta koncepcja Hare’a broni się przed tym zarzutem dzięki zawartemu w niej wymogowi uniwersalizacji. Natomiast Brandt zarzuca Hare’owi, że zgodnie z jego założeniami różni ludzie mogą formułować w sposób poprawny sprzeczne twierdzenia etyczne. W artykule zostają przedstawione argumenty za tym, że teoria Hare’a uniemożliwia uzasadnienie na jej gruncie sprzecznych twierdzeńetycznych, nie wyklucza jednak możliwości usprawiedliwienia takich praktyk jak niewolnictwo.

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Authors and Affiliations

Michał Piekarz
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Abstract

The work presents investigation on the water droplet impingement at a substrate with three different surface coating. The experiments are carried out for two temperatures of the surface: 23ºC (room temperature) and -10ºC. The water droplet contact is recorded via ultra-fast camera and simultaneously via fast thermographic camera. The wetting properties are changing for subzero temperatures of substrates.

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Bibliography

[1] A. Alizadeh,V. Bahadur, S. Zhong,W. Shang, R. Li, J. Ruud, M.Yamada, L. Ge, A. Dhinojwala, and M. Sohal. Temperature dependent droplet impact dynamics on flat and textured surfaces. Applied Physics Letters, 100(11):111601, 2012. doi: 10.1063/1.3692598.
[2] M. Nosonovsky and V. Hejazi. Why superhydrophobic surfaces are not always icephobic. ACS Nano, 6(10):8488–8491, 2012. doi: 10.1021/nn302138r.
[3] K.K. Varanasi, T. Deng, M. Hsu, and N. Bhate. Hierarchical superhydrophobic surfaces resist water droplet impact. In Technical Proceedings of the 2009 NSTI Nanotechnology Conference and Expo, Houston, Texas, USA, 3-7 May 2009. Nano Science and Technology Institute. http://hdl.handle.net/1721.1/64767.
[4] L. Mishchenko, B. Hatton, V. Bahadur, J.A. Taylor, T. Krupenkin, and J. Aizenberg. Design of ice-free nanostructured surfaces based on repulsion of impacting water droplets. ACS Nano, 4(12):7699–7707, 2010. doi: 10.1021/nn102557p.
[5] R. Ramachandran, K. Sobolev, and M. Nosonovsky. Dynamics of droplet impact on hydrophobic/icephobic concrete with the potential for superhydrophobicity. Langmuir, 31(4):1437–1444, 2015. doi: 10.1021/la504626f.
[6] T. Bobinski, G. Sobieraj, K. Gumowski, J. Rokicki, M. Psarski, J. Marczak, and G. Celichowski. Droplet impact in icing conditions – the influence of ambient air humidity. Archives of Mechanics, 66(2):127–142, 2014. http://am.ippt.pan.pl/index.php/am/article/view/v66p127.
[7] R. Rioboo, M. Marengo, and C. Tropea. Time evolution of liquid drop impact onto solid, dry surfaces. Experiments in Fluids, 33(1):112–124, 2002. doi: 10.1007/s00348-002-0431-x.
[8] N. Laan, K.G. de Bruin, D. Bartolo, C. Josserand, and D. Bonn. Maximum diameter of impacting liquid droplets. Physical Review Applied, 2(4):044018, 2014. doi: 10.1103/PhysRevApplied.2.044018.
[9] B.B.J. Stapelbroek, H.P. Jansen, E.S. Kooij, J.H. Snoeijer, and A. Eddi. Universal spreading of water drops on complex surfaces. Soft Matter, 10(15):2641–2648, 2014. doi: 10.1039/c3sm52464g.
[10] M. Remer, M. Psarski, K. Gumowski, J. Rokicki, G. Sobieraj, M. Kaliush, D. Pawlak, and G. Celichowski. Dynamic water contact angle during initial phases of droplet impingement. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 508:57–69, 2016. doi: 10.1016/j.colsurfa.2016.08.028.
[11] C.T. Crowe. Multiphase Flow Handbook, volume 59 of Mechanical and Aerospace Engineering Series. CRC Press, 2005.
[12] C. Stanley, R. Jackson, N. Karwa, and G. Rosengarten. The effects of surface wettability on droplet fingering. In The Proceedings of the 19th Australasian Fluid Mechanics Conference, Melbourne, Australia, 8-11 December 2014. Paper No. 49.
[13] A. Latka, A. Strandburg-Peshkin, M.M. Driscoll, C.S. Stevens, and S.R. Nagel. Creation of prompt and thin-sheet splashing by varying surface roughness or increasing air pressure. Physical Review Letters, 109(5):054501, 2012. doi: 10.1103/PhysRevLett.109.054501.
[14] T.G. Myers, J.P.F. Charpin, and C.P. Thompson. Slowly accreting ice due to supercooled water impacting on a cold surface. Physics of Fluids, 14(1):240–256, 2002. doi: 10.1063/1.1416186.
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Authors and Affiliations

Tomasz Lizer
1
Michał Remer
1
Grzegorz Sobieraj
1
Maciej Psarski
2
Daniel Pawlak
2
Grzegorz Celichowski
2

  1. Institute of Aeronautics and Applied Mechanics, Warsaw University of Technology, Poland.
  2. Faculty of Chemistry, Department of Materials Technology and Chemistry, University of Lodz, Poland.
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Abstract

In 2018 we celebrate the 250th anniversary of the Jędrzej Śniadecki’s birth. This work aims to show the importance of his thoughts for the development of natural sciences. He studied at some of the largest universities in Europe, where he met great scientists of the Enlightenment. The effects can be seen in his works. He was remembered as a founder of Polish biochemistry, anthropology and pathology, also as the author of chemical terminology and language. The essence of his thoughts is Theory of organic being, which is an attempt to answer the question: „what is life?”. Jędrzej Śniadecki introduced a new definition of life based on the term „organic power”. This work shows how import are the thoughts of Jędrzej Śniadecki in the context of the times in which he lived, as well as the following development of natural sciences, what makes him and his theories worth memory.

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Authors and Affiliations

Aniela Zubek
Jakub Barciszewski
Agnieszka Belter
Jan Barciszewski
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Abstract

Jerzy Kołodziejczak, who died on August 1st, 2022 at the age of 87, was a distinguished Polish physicist and a visionary science manager. He graduated at the Physics Faculty of Warsaw University in 1958, received PhD in 1961, habilitation in 1963, and became Professor in 1968. From the beginning of his brilliant and rapid scientific career he worked at the newly created Polish Academy of Sciences Institute of Physics in Warsaw, of which he became director in 1970 (for 12 years) and then the creator of the new institute site and its structure of today. His major theoretical and experimental contributions to science of semiconductors followed the observation that understanding of galvanomagnetic and optical phenomena of medium and narrow-gap semiconductors cannot be done without proper account of the nonparabolicity of their bands. He then formulated general theory of these properties, what brought him not only international acclaim, but also several highest recognitions in Poland (first Maria Skłodowska-Curie Scientific Prize of the Polish Academy of Sciences (PAS) in 1967, the State Award of the first class 1978, Polonia Restituta Commander Order with the Star 2005) and membership to the Polish Academy of Sciences (Corresponding Member 1973 and Ordinary Member in 1991). He served several highest offices in the Academy up to the Academy Presidency in 2002. In 1983 was elected a Fellow of the Warsaw scientific Society. He published well over 100 scientific papers and was a Ph Thesis advisor of his 15 associates.
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Authors and Affiliations

Jerzy M. Langer
1

  1. Instytutu Fizyki PAN, Warszawa

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