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Number of results: 5
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Abstract

The paper describes a mathematical model of gas flow through crevices between the piston, rings and cylinder in internal combustion engines. The model has been developed to study the influence of numerous. design parameters and engine operation condition on piston ring pack behaviour and the exhaust gases blowby from the combustion chamber to the crankcase. The model integrates the gas flow and axial rings displacements in the grooves, and separately treats lands between piston, cylinder and adjacent rings and regions in the grooves behind the rings. The heat transfer between the gas and the surrounding surfaces is calculated and emphasis is placed on considering the influence of wear and thermal deformations of elements on ring pack performance.
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Authors and Affiliations

Grzegorz Koszałka
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Abstract

The paper presents the results of laboratory tests of SCB (semi-circular beam) samples of asphalt concrete, subjected to the destructive effect of water and frost as well as the aging processes. The determined values of material parameters show significant dispersions, which makes the design of mixtures difficult. Statistical analysis of the test results supplemented by computer simulations made with the use of the proprietary FEM model was carried out. The main distinguishing feature of the model is the assignment of material parameters of coarse aggregate and bituminous mortar to randomly selected finite elements. The parameters of the mortar are selected by trial and error to match the numerical results to the experimental ones. The stiffness modulus of the bituminous mortar is, therefore, a substitute parameter, taking into account the influence of many factors, including material degradation resulting from the aging and changing environmental conditions, the influence of voids, and contact between the aggregate and the bituminous mortar. The use of the Monte Carlo method allows to reflect the scattering of the results obtained based on laboratory tests. The computational algorithm created in the ABAQUS was limited only to the analysis of the global mechanical bending response of the SCB sample, without mapping the failure process in detail. The combination of the results of laboratory tests usually carried out on a limited number of samples and numerical simulations provide a sufficiently large population of data to carry out a reliable statistical analysis, and to estimate the reliability of the material designed.
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Authors and Affiliations

Cezary Szydłowski
1
ORCID: ORCID
Łukasz Smakosz
2
ORCID: ORCID
Marcin Stienss
1
ORCID: ORCID
Jarosław Górski
2
ORCID: ORCID

  1. Gdansk University of Technology, Faculty of Civil and Environmental Engineering, Department of Highway and Transportation Engineering, 11/12 Gabriela Narutowicza Street, 80-233 Gdansk, Poland
  2. Gdansk University of Technology, Faculty of Civil and Environmental Engineering, Department of Structural Mechanics, 11/12 Gabriela Narutowicza Street, 80-233 Gdansk, Poland
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Abstract

The aim of this research was to model the performances of energy and exergy on a Trombe wall system to enable an adequate thermal comfort. The main equations for the heat transfer mechanisms were developed from energy balances on subcomponents of the Trombe wall with the specification of the applicable initial and boundary conditions. During the incorporation of the PCM on the Trombe wall, the micro-encapsulation approach was adopted for better energy conservation and elimination of leakage for several cycling of the PCM. The charging and discharging of the PCM were equally accommodated and incorporated in the simulation program. The results of the study show that an enhanced energy storage could be achieved from solar radiation using PCM-augmented system to achieve thermal comfort in building envelope. In addition, the results correspond with those obtained from comparative studies of concrete-based and fired-brick augmented PCM Trombe wall systems, even though a higher insolation was used in the previous study.
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Bibliography

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[2] A. Mastrucci. Experimental and Numerical Study on Solar Walls for Energy Saving, Thermal Comfort and Sustainability of Residential Buildings. Ph.D. Thesis, University Politecnica delle Marche, Italy, 2013.
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[4] L. Zalewski, A. Joulin, S. Lassue, Y. Dutil, and D. Rousse. Experimental study of small-scale solar wall integrating phase change material. Solar Energy, 86(1):208–219, 2012. doi: 10.1016/j.solener.2011.09.026.
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[7] F. Kuznik and J. Virgone. Experimental assessment of a phase change material for wall building use. Applied Energy, 86(10):2038–2046, 2009. doi: 10.1016/j.apenergy.2009.01.004.
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[10] L. Cao, F. Tang, and G. Fang. Synthesis and characterization of microencapsulated paraffin with titanium dioxide shell as shape-stabilized thermal energy storage materials in buildings. Energy and Buildings, 72:31–37, 2014. doi: 10.1016/j.enbuild.2013.12.028.
[11] F. Abbassi and L. Dehmani. Experimental and numerical study on thermal performance of an unvented Trombe wall associated with internal thermal fins. Energy and Buildings, 105:119–128, 2015. doi: 10.1016/j.enbuild.2015.07.042.
[12] M.J. Huang, P.C. Eames, and N. J. Hewitt. The application of a validated numerical model to predict the energy conservation potential of using phase change materials in the fabric of a building. Solar Energy Materials and Solar Cells, 90(13):1951–1960, 2006. doi: 10.1016/j.solmat.2006.02.002.
[13] S.A. Ajah, B.O. Ezurike, and H.O. Njoku. A comparative study of energy and exergy performances of a PCM-augmented cement and fired-brick Trombe wall systems. International Journal of Ambient Energy, 1–18, 2020. doi: 10.1080/01430750.2020.1718753.
[14] H.O. Njoku, B.E. Agashi, and S.O. Onyegegbu. A numerical study to predict the energy and exergy performances of a salinity gradient solar pond with thermal extraction. Solar Energy, 157:744–761, 2017. doi: 10.1016/j.solener.2017.08.079.
[15] C. Ji, Z. Qin, S. Dubey, F.H. Choo, and F. Duan. Three-dimensional transient numerical study on latent heat thermal storage for waste heat recovery from a low temperature gas flow. Applied Energy, 205:1–12, 2017. doi: 10.1016/j.apenergy.2017.07.101.
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Authors and Affiliations

Benjamin O. Ezurike
1
ORCID: ORCID
Stephen A. Ajah
1
ORCID: ORCID
Uchenna Nwokenkwo
1
ORCID: ORCID
Chukwunenye A. Okoronkwo
1
ORCID: ORCID

  1. Department of Mechanical/Mechatronics Engineering, Alex Ekwueme Federal University Ndufu-Alike, Nigeria
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Abstract

In the article the question about the issue of beauty and energy in Polish architecture is considered in the context of experience in the design of buildings and housing estates collected in the last twenty years by the Warsaw studio Grupa 5 Architekci. The conceptual, urban and architectural assumptions are illustrated by three examples representative of different, key problem issues.

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Authors and Affiliations

Michał Leszczyński
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Abstract

Punktem wyjścia rozważań jest dysproporcja w udziale obu płci w tworzeniu filozofii w Polsce, Wielkiej Brytanii i w wielu innych krajach na świecie. Dysproporcja ta skłania do postawienia pytania o to, co z perspektywy samej filozofii mogłoby zostać zrobione w celu zapobiegania tej oraz innym formom filozoficznej i intelektualnej dyskryminacji. Celem artykułu jest pokazanie, iż to klasyczny pragmatyzm (koncepcje Peirce’a, Jamesa i Deweya) jest źródłem metafilozoficznych idei pluralizmu, egalitaryzmu oraz włączania (inclusiveness), które pozwalają na nowo zdefiniować podmiot, przedmiot i cele praktyki filozoficznej.

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Authors and Affiliations

Agnieszka Hensoldt

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