Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 7
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

Badania ostatnich lat nie tylko wzbogaciły naszą wiedzę o mechanizmach słodkiego smaku, ale też o jego inhibitorach. Słodziki i inhibitory odkryte przez Polaków zostały opatentowane.
Go to article

Authors and Affiliations

Piotr Krajewski
Download PDF Download RIS Download Bibtex

Abstract

Research conducted in recent years has greatly improved our understanding of the underlying mechanisms of sweet taste, as well as its inhibitors. A number of sweeteners and inhibitors discovered by Polish researchers have been patented.
Go to article

Authors and Affiliations

Piotr Krajewski
ORCID: ORCID
Download PDF Download RIS Download Bibtex

Abstract

The subject of the wind tunnel tests is a steel chimney 85 m high of cylindrical – type structure with a grid-type curtain structure situated at its upper part. The model of the upper part of the chimney made in the scale of 1:19 was equipped with 3 levels of wind pressure measurement points. Each level contained 24 points connected with pressure scanners. On the base of the pressure measurements, both mean and instantaneous aerodynamic drag and side force coefficients were determined. Next wind gust factors for these two wind action components were determined. Moreover, for each pressure signal Fast Fourier Transform was done. Mean wind action components were also determined using stain gauge aerodynamic balance. Obtained results make possible to conclude that the solution applied in the upper part of the designed chimney is correct from building aerodynamics point of view. Some minor vortex excitations were observed during model tests of the upper part of the chimney. The basic dynamic excitation of this part of the chimney is atmospheric turbulence.
Go to article

Bibliography



[1] Zdravkovich M.M., “Review and classification oof various aerodynamic and hydrodynamic means for suppressing vortex shedding”. J.Wind Eng. Ind. Aerodyn., 7(2): pp. 145-189, 1981.
[2] Arunachalam, S., & Lakshmanan, N. (2015). “Across-wind response of tall circular chimneys to vortex shedding”. Journal of Wind Engineering and Industrial Aerodynamics, 145, pp. 187–195, https://doi.org/10.1016/j.jweia.2015.06.005.
[3] Wang, L., & Fan, X. (2019). “Failure cases of high chimneys: A review”. Engineering Failure Analysis, 105, pp. 1107–1117, https://doi.org/10.1016/j.engfailanal.2019.07.032.
[4] Vickery, B. J., & Basu, R. I., “The response of reinforced concrete chimneys to vortex shedding”. Engineering Structures, 6(4), pp. 324–333, 1974
[5] Flaga A., “Wind vortex-induced excitation and vibration of slender structures-single structure of circular cross-section normal to flow”. Monograph No. 202. Cracow University of Technology, Cracow 1996.
[6] Lipecki, T., & Flaga, A. (2013). “Vortex excitation model. Part I. mathematical description and numerical implementation”. Wind and Structures, 16(5), pp. 457–476.
[7] Lipecki, T., & Flaga, A. (2013). “Vortex excitation model. Part II. application to real structures and validation”. Wind and Structures, 16(5), pp. 477–490, https://doi.org/10.12989/was.2013.16.5.477.
[8] Brownjohn, J. M. W., Carden, E. P., Goddard, C. R., & Oudin, G. (2010). “Real-time performance monitoring of tuned mass damper system for a 183 m reinforced concrete chimney”. Journal of Wind Engineering and Industrial Aerodynamics, 98(3), pp. 169–179, https://doi.org/10.1016/j.jweia.2009.10.013.
[9] Christensen, R. M., Nielsen, M. G., & Støttrup-Andersen, U. (2017). “Effective vibration dampers for masts, towers and chimneys”. Steel Construction, 10(3), pp. 234–240, https://doi.org/10.1002/stco.201710032.
[10] Belver, A. V., Ibán, A. L., & Lavín Martín, C. E. (2012). “Coupling between structural and fluid dynamic problems applied to vortex shedding in a 90m steel chimney”. Journal of Wind Engineering and Industrial Aerodynamics, 100(1), pp. 30–37. .
[11] Verboom, G. K., & van Koten, H. (2010). “Vortex excitation: Three design rules tested on 13 industrial chimneys”. Journal of Wind Engineering and Industrial Aerodynamics, 98(3), pp. 145–154, https://doi.org/10.1016/j.jweia.2009.10.008.
[12] Kawecki, J., & Żurański, J. A. (2007). ”Cross-wind vibrations of steel chimneys – A new case history”. Journal of Wind Engineering and Industrial Aerodynamics, 95(9–11), pp. 1166–1175.
[13] Lupi, F., Höffer, R., & Niemann, H.-J. (2021). “Aerodynamic damping in vortex resonance from aeroelastic wind tunnel tests on a stack”. Journal of Wind Engineering and Industrial Aerodynamics, 208, pp. 104–438.
[14] Lupi, F., Niemann, H.-J., & Höffer, R. (2017). “A novel spectral method for cross-wind vibrations: Application to 27 full-scale chimneys”. Journal of Wind Engineering and Industrial Aerodynamics, 171, pp. 353–365, https://doi.org/10.1016/j.jweia.2017.10.014.
[15] Rahman, S., Jain, A. K., Bharti, S. D., & Datta, T. K. (2020). “Comparison of international wind codes for across wind response of concrete chimneys”. Journal of Wind Engineering and Industrial Aerodynamics, 207, pp. 104–401.
[16] Ruscheweyh H., “Dynamische Windwirkung an Bauwerken. Band 2: Praktische Anwendungen. Bauverlag”. Wiesbaden und Berlin, 1982.
[17] Blevins R.D., “Flow-induced vibration. Second edition”. Van Nostrand Reinhold, New York 1990.
[18] Flaga A., “Wind engineering – fundamentals and applications” (in Polish), Arkady, Warsaw (2008).
Go to article

Authors and Affiliations

Andrzej Flaga
1
ORCID: ORCID
Renata Kłaput
1
ORCID: ORCID
Łukasz Flaga
1
ORCID: ORCID
Piotr Krajewski
1
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Civil Engineering, Wind Engineering Laboratory, Jana Pawła II 37/3a, 31-864 Cracow
Download PDF Download RIS Download Bibtex

Abstract

It is highly important to determine eigenvalues before and after certain extreme events that may cause damage accumulation, such as earthquake, blasts and mining or seismic tests on research models. Unique experiment design and shake table testing was performed to investigate seismic performance of a 3D RC building model with infill walls and advanced protection with polyurethane-based joints and fiber polymer reinforced light and emergency jackets. For the purpose of wider experimental activities, three methods for determination of the dynamic characteristics were used during multiple successive shake table tests following a dynamic pushover approach, and they are presented in detail. They are: inertance function through impact hammer tests, standard Fourier transformation of measured acceleration time history and digital image correlation. The expected differences in the results are related to the type and intensity of excitation used, the involvement of materials with different mechanical and physical properties, and with the different rate and extent of damage accumulation, as well as to local or global measurements. Y et, all methods lead to reliable results when a consistent methodology is being used, that takes into account locality or globality of measurements, leaving a choice for the most suitable one, depending on the site conditions. The inertance function method presented manifested its high efficiency in analysis of dynamic properties of large-scale structures and in monitoring of their changes caused by the damage and repair process. It offers quite a wide range of useful information, does not require very expensive equipment and its transportation cost is negligible. This method seems to be a proper diagnostic tool for simple experimental modal analysis of real structures and their structural elements, where detection of changes in the structural condition and in dynamic properties is required, also as a non-destructive testing and monitoring method. Digital image correlation proved to be a promising non-contact tool, strongly supporting the conventional instrumentation of shake table testing, while the Fourier transformation was used as a benchmark method yielding the most reliable results.
Go to article

Authors and Affiliations

Arkadiusz Kwiecień
1
ORCID: ORCID
Zoran Rakicevic
2
Jarosław Chełmecki
1
Aleksandra Bogdanovic
2
Marcin Tekieli
1
Łukasz Hojdys
1
Matija Gams
3
Piotr Krajewski
1
ORCID: ORCID
Filip Manojlovski
2
Antonio Soklarovski
2
Omer Faruk Halici
4
Theodoros Rousakis
Vachan Vanian
5

  1. Faculty of Civil Engineering, Cracow University of Technology, Cracow, Poland
  2. IZIIS, Ss. Cyril and Methodius University, Skopje, North Macedonia
  3. Faculty of Civil and Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia
  4. Istanbul Technical University, Istanbul, Turkey
  5. Democritus University of Thrace, Xanthi, Greece

This page uses 'cookies'. Learn more