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Abstract

This paper presents an experimental analysis of flexural capacity and deformability of structural concrete slabs prepared as composite members consisting of two concrete layers made of reinforced ordinary concrete (N) and fiber reinforced concrete (SFRC). The reinforced concrete composite slabs used in the tests were prepared in the dimensions of 600 x 1200 x 80 mm. The basis was composed of two layers consisting of SFRC, one as the top layer, and one as ordinary concrete. The results of the analysis confirm a significant improvement of structural properties of the composite slab in comparison to the slabs prepared wholly of ordinary concrete.

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Authors and Affiliations

B. Sadowska-Buraczewska
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Abstract

The aim of the study was to examine the efficiency of the thermal wave type adsorption refrigerating equipment working on a pair of activated carbon and methanol. Adsorption units can work in trigeneration systems and in applications driven by waste heat. They can be built also as a part of hybrid sorption-compressor systems, and they are very popular in solar refrigeration systems and energy storage units. The device examined in this study operates in a special mode called thermal wave. This mode allows to achieve higher efficiency rates than the normal mode of operation, as a significant contributor to transport heat from one to the other adsorber. To carry out the experiment a test bench was built, consisting of two cylindrical adsorbers filled with activated carbon, condenser, evaporator, oil heater and two oil coolers. Thermal oil circulation was responsible for providing and receiving heat from adsorbers. In order to perform the correct action a special control algorithm device was developed and implemented to keep the temperature in the evaporator at a preset level. The experimental results show the operating parameters changes in both adsorbers. Obtained COP (coefficient of performance) for the cycle was 0.13.

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Authors and Affiliations

Artur Rusowicz
Andrzej Grzebielec
Rafał Laskowski
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Abstract

The accumulation of moisture from autumn and winter precipitation in poorly draining soil for plants in arid conditions during the initial stage of the vegetation period in the northern region of Kazakhstan was a severe production problem. Research methods included theoretical and experimental studies. In theoretical studies, the area of the treated surface by a chain harrow is determined. Then, the design of an improved harrow is proposed, including how the tooth chain tillage tools are positioned. Either as a “single action disc harrow” type with mounting four teeth on each chain link, or as a serial harrow with the tooth chain tillage tools located in a “diamond-shaped” double-action scheme with two teeth on each chain link. Experimental studies show that an improved harrow steadily performs the early spring harrowing process with a quality that meets normative requirements. In doing, so the working capacity is 4–5% higher than a serial harrow with a 4–5% lower fuel consumption. Furthermore, it is revealed that the early spring soil harrowing performed by tooth chain harrows allows the loss of productive moisture in the spring pre-sowing period by 1.8–1.9 times to be reduced compared to the untreated background.
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Authors and Affiliations

Vladimir L. Astafyev
1
ORCID: ORCID
Alexandr A. Kurach
1
ORCID: ORCID
Maxat A. Amantayev
1
ORCID: ORCID

  1. Kostanay Branch of “Scientific Production Center of Agricultural Engineering” LLC, 110011, Abai Avenue, 34, Kostanay, 110011, Kazakhstan
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Abstract

The paper concerns the computations of mast guys taking into account both geometric and physical nonlinearities. Experimental studies have been conducted, the aim of which was to determine σ - ε (stress – deformation) relation for steel rope and to determine the value of modulus of elasticity after its pre-stretching. Results of the research were used to create appropriate computational cable models within the elastic and inelastic range in SOFiSTiK software, based on FEM. The computational cable models were then used to perform parametric analyses of single cables with horizontal and diagonal chords and computations of a lattice guyed mast. The computational single cables results obtained in the SOFiSTiK software were confronted with the results obtained by the analytical method, based on the cable equation. The FEM analyses performed for single cables have proven usefulness of presented analytical procedure for computation of structures with cable elements (e.g. guyed masts) taking into account both the geometric and physical nonlinearity of the cables. It has been shown that while using steel ropes without pre-stretching, permanent deformations in the cables may occur, which affect the shape of the cable and may significantly reduce values of forces in the cables. This phenomenon can be particularly dangerous in the case of guyed masts, as it may affect the reduction in rigidity of the mast structure.
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Bibliography

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Authors and Affiliations

Monika Matuszkiewicz
1
ORCID: ORCID
Renata Pigoń
1
ORCID: ORCID

  1. Koszalin University of Technology, Faculty of Civil Engineering, Environmental and Geodetic Sciences, Sniadeckich 2, 75-453 Koszalin, Poland

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