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Abstract

This article presents some results of work on the selection of the most promising types of lamps for various objects in industry, in commercial and residential buildings. It is shown that the use of a particular type of lamp depends on the conditions of a particular country (the cost of credit resources, the availability of different types of lamps on the market, and government incentives or restrictions), as well as on the conditions of the specific object (cost of lamps, duration of operation during the day, tariffs for energy resources, the cost of equipment and its installation (dismantling, utilization), the cost of replacing the equipment after leaving it, the term of service of various types of lamps). It is also necessary to consider the possible risks of changes in tariffs and the cost of money.
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Authors and Affiliations

Volodymyr Mamalyga
1
ORCID: ORCID

  1. National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Ukraine
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Abstract

Use of the poroelasticity theory by Biot in the description of rock behaviour requires the value of the e.g. Biot coefficient α to be determined. The α coefficient is a function of two moduli of compressibility: the modulus of compressibility of the rock skeleton Ks and the effective modulus of compressibility K. These moduli are determined directly on the basis of rock compressibility curves obtained during compression of a rock sample using hydrostatic pressure. There is also a concept suggesting that these compressibility moduli might be determined on the basis of results of the uniaxial compression test using the fact that, in the case of an elastic, homogeneous and isotropic material, the modulus of compressibility of a material is a function of its Young modulus and its Poisson ratio. This work compares the results obtained from determination of the Biot coefficient by means of results of compressibility test and uniaxial compression test. It was shown that the uniaxial compression test results are generally unsuitable to determine the value of the coefficient α. An analysis of values of the determined moduli of compressibility shows that whereas the values of effective moduli of compressibility obtained using both ways may be considered as satisfactorily comparable, values of the relevant rock skeleton moduli of compressibility differ significantly.
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Bibliography

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[6] J . Gustkiewicz, Compressibility of rocks with a special consideration given to pore pressure. In: Thismus et al. (Eds.), Poromechanics – A Tribute to Maurice A. Biot. Proceedings of the Biot Conference on Poromechanics, Louvain-la-Neuve (Belgium), 14-16 September 1998, Balkema, Rotterdam (1998).
[7] M. Lion, F. Skoczylas, B. Ledésert, Determination of the main hydraulic and poroelastic properties of a limestone from Bourgogne, France. Int. J. Rock Mech. Min. Sci. 41, 915-925 (2004).
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[12] H .F. Wang, Theory of Linear Poroelasticity with Applications to Geomechanics and Hydrogeology. 2000 Princeton University Press, Princeton & Oxford.
[13] Z .T. Bieniawski, J.A. Franklin, M.J. Bernede, P. Duffaut, F. Rumpel, T. Horibe, F. Broch, E. Rodrigues, W.E. van Heerden, U.W. Vogler, I. Hansagi, J. Szlavin, B.T. Brady, D.U. Deere, I. Hawkes, D. Milovanovic, Suggested Methods for Determining the Uniaxial Compressive Strength and Deformability of Rock Materials. Int. J. Rock Mech. Min. Sci. & Geomech. Abstr. 16 (2), 135-140 (1979).
[14] K . Kovári, A. Tisa, H.H. Einstein, J.A. Franklin, Suggested Methods for Determining the Strength of Rock Materials in Triaxial Compression: Revised Version. Int. J. Rock Mech. Min. Sci. & Geomech. Abstr. 20 (6), 283-290 (1983).
[15] M. Długosz, J. Gustkiewicz, A. Wysocki, Apparatus for investigation of rock in three-axial state of stress. Part I. Characteristics of the apparatus and of the investigation method. Arch. Min. Sci. 26 (1), 17-28 (1981).
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[19] R. Přikryl, J. Prikrylová, M. Racek, Z. Weishauptová, K. Kreislová, Decay mechanism of indoor porous opuka stone: a case study from the main altar located in the St. Vitus Cathedral. Environmental Earth Sciences 76 (2017).
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Authors and Affiliations

Andrzej Nowakowski
1
ORCID: ORCID
Janusz Nurkowski
1
ORCID: ORCID

  1. Strata Mechanics Research Institute of the Polish Academy of Science, 27 Reymonta Str., 30-059 Kraków, Poland
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Abstract

The objective of the presented paper is to investigate the performance of concrete containing volcanic scoria as cement replacement after 7, 28, 90, and 180 days curing. Five performance indicators have been studied. Compressive strength, water permeability, porosity, chloride penetrability, and reinforcement corrosion resistance have all been evaluated. Concrete specimens were produced with replacement levels ranging from 10 to 35%. Test results revealed that curing time had a large influence on all the examined performance indicators of scoria-based concrete. Water permeability, porosity, and chloride penetrability of scoria-based concrete mixes were much lower than that of plain concrete. Concretes produced with scoria-based binders also decelerated rebar corrosion, particularly after longer curing times. Furthermore, an estimation equation has been developed by the authors to predict the studied performance indicators, focusing on the curing time and the replacement level of volcanic scoria. SEM/EDX analysis has been reported as well.

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Authors and Affiliations

A. M. al-Swaidani

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