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Number of results: 8
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Abstract

The article presents a synthetic analysis of the crude oil market in Poland. As of today, this safety is provided mainly on the basis of native lignite and hard coal resources. However, the analysis of the hard coal market conducted by the authors indicates that the carried out mining restructuring (among others) led to an excessive reduction of mining volume and employment level in the hard coal mining sector. This led to a precedent situation when Poland became an importer of this energy carrier. In addition, the European Union’s requirements for greenhouse gas emissions must be taken into account. In connection with the above, it is necessary to search for new energy sources or technologies that enable hard coal to meet the requirements. It is possible to apply the so-called clean coal technologies that allow the greenhouse gas emissions generated during coal combustion to be reduced. As of today, they are not used on a mass scale, because the use of this type of technology involves additional financial expenses. However, taking into account that technologies have been growing faster and faster, are modernized in a shorter time, making a breakthrough discovery took hundreds of years, now it is often a few months, clean coal technologies can become the optimal solution in the near future. It is also necessary to diversify the sources of obtaining imported energy carriers.

The article describes coal and crude oil in terms of their mutual substitution. The article is a continuation of research conducted by the authors. Previous publications presented considerations on analogous topics related to natural gas and renewable energy sources. The crude oil market in Poland was analyzed and forecasts for oil extraction and the demand in the world and Poland by 2023 were presented. The SARIMA model was also created. The model made it possible to obtain oil an prices forecast.

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Authors and Affiliations

Aurelia Rybak
ORCID: ORCID
Anna Manowska
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Abstract

The article examines the trends in the development of renewable energy in Ukraine in accordance

with the long-term strategy of the energy sector of the state in the context of the transformation

of employment in the energy sector of the country. It is emphasized that investments in renewable

energy technologies create more jobs compared to traditional electricity generation technologies.

It is defined that in Ukraine there is a significant untapped potential for energy efficiency, which

requires accelerating the pace of modernization and development of renewable energy sources and

raises the issue of labor supply to the industry. It was emphasized that there are a number of opportunities

for the development of the energy sector of Ukraine related to the development of renewable

energy sources. It is underlined that the formation of territorial-industrial clusters in Ukraine

for the production of equipment for solar and wind energy with a closed production cycle forms

long-term prerequisites for socio-economic stability in the country and stimulates employment. It is

substantiated that an important reserve for increasing employment in Ukraine is to ensure the energy

efficiency of buildings. At the same time, it was noted that in the field of renewable energy and

energy efficiency in Ukraine there is a significant shortage of qualified technicians and specialists

in the field of innovative technologies, which confirms the importance of studying the problem of

labor support in the industry. It is determined that today the solution of the issue of labor supply

of the industry takes place mainly at the level of enterprises that invest in the development of their

own staff.

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Authors and Affiliations

Svitlana Kalinina
ORCID: ORCID
Olena Lyndiuk
ORCID: ORCID
Volodymyr Buchyk
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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 well-known Manning formula is usually used for the calculation of the calculative volumetric flow rate in a river or open canal. The discharge depends on the geometry of the channel, i.e. the water area, the wetted perimeter and the slope, as well as on the roughness coefficients. All these quantities are determined with some uncertainty. The article proposes a methodology for calculating the uncertainty of the roughness coefficients of the riverbed and the floodplain as well as the uncertainty of the geometric dimensions of the riverbed. Then, the method of calculating the uncertainty of the calculative discharge is then given. If these uncertainties are taken into consideration in the process of discharge calculation, then, as has been demonstrated for a hypothetical river channel, the ratio of the uncertainty to the calculated value of the discharge will change from several dozen percent in case of small flows to about ten percent in case of big, flood flows. It has also been shown that the uncertainty of the roughness coefficients has the biggest influence on the uncertainty of the flow rate. The presented calculations show that in order to take into account the influence of uncertainty of linear dimensions and roughness coefficients, the engineer designing the riverbed should assume for the calculations the flow rate increased by 10% then design flow. The obtained results can be used for homogeneous flows only, which is usually assumed in practical engineering calculations.
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Authors and Affiliations

Leszek Oprychał
1
ORCID: ORCID
Aleksandra Bąk
1
ORCID: ORCID

  1. Military University of Technology, Department of Civil Engineering and Geodesy, ul. gen. Sylwestra Kaliskiego 2, 00 -908 Warsaw, Poland
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Abstract

The aim of the study is to determine the mercury content in hard coal, randomly taken from the USCB and in by-products of hard coal mining (fresh mining waste), i.e. aggregates (gangue) and hard coal sludge and mining waste from the Siersza dump (weathered waste). The 34 samples were intended for analysis. The total mercury content and the amount of mercury leaching from solid samples was determined. The percentage of the leaching form in the total element content, i.e. the level of mercury release from the material (leaching level), was also calculated. The amount of mercury leaching was determined by a static method using a batch test 1:10. The highest possibility of leaching mercury is characterized by weathered waste from the Siersza dump and slightly lower analyzed hard coal from the U pper Silesian Coal Basin (USCB). For hard coal samples, the total mercury content is between 0.0275–0.1236 mg/kg. However, the amount of mercury leaching from coal samples is 0.0008–0.0077 mg/kg. The aggregate is characterized by a higher total mercury content in the finest fraction 0–6 mm, within 0.1377–0.6107 mg/kg and much lower in the 80-120 mm fraction, within 0.0508–0.1274 mg/kg. The amount of elution is comparable in both fractions and amounts to 0.0008–0.0057 mg/kg. Coal sludge has a total mercury content of 0.0937–0.2047 mg/kg. L ow leaching values of 0.0014–0.0074 mg/ kg are also observed. Weathered mining waste has a total mercury content of 0.0622–0.2987 mg/kg. However, leaching values from weathered waste are much higher than from fresh mining waste. This value is 0.0058–0.0165 mg/kg. In the hard coal extracted from U SCB, the leaching level is 4.7% on average. Mining waste is characterized by a large variation in the proportion of mercury leaching form and the differences result from the seasoning time of the samples. Waste or by-products of hard coal production, such as aggregates and coal sludge, show a mercury washout form at an average level of 1.7%. The proportion of leachable form in weathered waste increased strongly to 7.3%. Elution characteristics vary for different groups of materials tested. Factors such as the type and origin of samples, their granulometric composition and the seasoning time of the material are of fundamental importance and demonstrated in the work.

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Authors and Affiliations

Beata Klojzy-Karczmarczyk
Janusz Mazurek
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Abstract

Contemporary school is exposed to a number of tensions and conflicts arising from the difference in expectations of everyday interactions. in particular, this can manifest itself in difficult situations for which shall be the student's social maladjustment or a threat to social maladjustment, because the multiplicity of involved actors can express different beliefs about the same substance and procedure changes desired and their effectiveness. The solution thus understood the conflict of expectations may be an institutional alliance, instead too far-reaching assumptions about the collaboration.

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Authors and Affiliations

Ilona Fajfer-Kruczek
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Abstract

The paper presents a proposal for the assessment of the reliability of steel truss (both statically determinate and indeterminate) in the persistent and accidental design situation. In the analysis, a probabilistic approach was used. The global Hasofer-Lind reliability index was employed, computed in successive time steps for the whole structure, not for individual elements. The statically determinate truss was modelled as a serial system from the reliability standpoint. For the statically indeterminate truss, kinematically admissible failure mechanisms were determined by means of the examination of the singularity of the stiffness matrix of the structure, converting the truss into a geometrically variable system. For the problem thus formulated, a serial-parallel reliability model was constructed. Monitoring the reliability index in the successive minutes of the fire makes it possible to estimate the probability of the structure failure, and to decide whether the required safety level is maintained.

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Authors and Affiliations

K. Kubicka
U. Radoń

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