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Number of results: 9
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Abstract

The article presents results of the author’s bachelor thesis, which deals with detailed cataloguing and analysing of findings of so-called Scythian character in the Moravia in the late Early Iron Age period. The author based this article on catalogue from his thesis. Relevant analogies and typological assignments were studied for concerning every subject in the catalogue and on their basis there was made general chronological classification of each piece. The aim of this article is to present observations that resulted from a detailed evaluation, on its basis occurrence of the subjects of so-called Scythian origin in the Moravia were divided into three time horizons.

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Authors and Affiliations

Ondřej Klápa
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Abstract

A large number of infrastructural concrete buildings are protected against aggressive environments by coating systems. The functionality of these coating systems is mainly affected by the composition and thickness of the individual polymeric layers. For the first time ever, a mobile nuclear magnetic resonance (NMR) sensor allows a non-destructive determination of these important parameters on the building site. However, before this technique can be used on steel-reinforced concrete elements, the potential effect of the reinforcement on the measurement, i.e. the NMR signal, needs to be studied. The results show a shift of the NMR profile as well as an increase of the signals amplitude in the case of the reinforced samples, while calculating the thickness of concrete coating leading to identical results.

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Authors and Affiliations

J. Orlowsky
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Abstract

Two fundamental challenges in investigation of nonlinear behavior of cantilever beam are the reliability of developed theory in facing with the reality and selecting the proper assumptions for solving the theory-provided equation. In this study, one of the most applicable theory and assumption for analyzing the nonlinear behavior of the cantilever beam is examined analytically and experimentally. The theory is concerned with the slender inextensible cantilever beam with large deformation nonlinearity, and the assumption is using the first-mode discretization in dealing with the partial differential equation provided by the theory. In the analytical study, firstly the equation of motion is derived based on the theory of large deformable inextensible beam. Then, the partial differential equation of motion is discretized using the Galerkin method via the assumption of the first mode. An exact solution to the obtained nonlinear ordinary differential equation is developed, because the available semi analytical and approximated methods, due to their limitations, are not always sufficiently reliable. Finally, an experiment set-up is developed to measure the nonlinear frequency of oscillations of an aluminum beam within a domain of initial displacement. The results show that the proposed analytical method has excellent convergence with experimental data.

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Authors and Affiliations

Majid Jamal-Omidi
Mahdi Shayanmehr
Saeid Sazesh
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Abstract

The environment in general and the marine environment in particular forms an ecosystem. Such ecosystem is characterized by high interconnectivity and interdepen-dence of species inhabiting it. Often enough, marine ecosystems far exceed the limits of the State’s sovereignty. Thus, their effective protection and preservation shall be carried out on a cooperative basis, engaging all States sharing common environment. The first international treaty to tackle the issue of marine environmental protection on a systemic basis is the United Nations Convention on the Law of the Sea (UNCLOS). It is also a treaty which directly established an obligation to cooperate in ensuring this protection. However, homogenous international regulation is not capable of addressing regional varying circumstances of marine environment. As the example of the South China Sea shows, lack of cooperation between coastal States can result in an irreversible damage to the environment. On the other hand, a remarkable model of effective realization of the obligation to cooperate has been established in the region of the Baltic Sea. What we can learn from these experiences is that fulfillment of the obligation to cooperate on a re-gional basis is a prerequisite for effective protection and preservation of the marine environment.

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Authors and Affiliations

Karolina Letniowska
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Abstract

Washing is very popular technological operation removing clay particles from aggregates. The amount of mineral washing sludges increases. Besides filling the excavations, there is no common method of their utilization. The usage of sludges from washing aggregates in building ceramics might be environmentally friendly way to utilize them.

This paper presents laboratory research on two type of sludges: from dolomite and limestone aggregates washing. Selected properties of sludges such as water content, particle size distribution (sieve and areometric method), chemical composition (XRF), mineral composition (XRD), thermal properties (STA/EGA, dilatometry, heating microscopy) and stability of fired materials during steam exposure were determined.

It was found that dolomite sludge contains more clay minerals and less carbonates, it is more finely grained than limestone sludge. Limestone sludge has large fluctuations in water content and has high content of potentially hazardous calcite grains. During heating up to 1300°C of both dried sludges decarbonation and sintering take place. Dolomite sludge softens, melts and flows below 1300°C. After firing sludges at 1000°C material made of limestone sludge is not resistant to steam.

The obtained result suggests that dolomite sludge can be used in building ceramics technology without processing as main component of ceramic mass. Limestone sludge have to be ground before its application in building ceramic materials. Results suggest that it can not be used as the main raw material in ceramic masses, but only as an additive.

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Authors and Affiliations

Ewelina Kłosek-Wawrzyn
Anna Bugaj
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Abstract

Due to high performance demands of grid-connected pulse-width modulation (PWM) converters in power applications, backstepping control (BSC) has drawn wide research interest for its advantages, including high robustness against parametric variations and external disturbances. In order to guarantee these advantages while providing high static and dynamic responses, in this work, a robust BSC (RBSC) with consideration of grid-connected PWM converter parameter uncertainties is proposed for three-phase grid-connected four-leg voltage source rectifiers (GC-FLVSR). The proposed RBSC for GC-FLVSR is composed of four independent controllers based on the Lyabonov theory that control DC bus voltage and input currents simultaneously. As a result, unit power factor, stable DC-bus voltage, sinusoidal four-leg rectifier input currents with lower harmonics and zero-sequence (ZS), and natural currents can be accurately achieved. Furthermore, the stability and robustness against load, DC capacitor, and filter inductance variations can be tested. The effectiveness and superiority of the proposed RBSC compared to the PI control (PIC) have been validated by processor-inthe- loop (PIL) co-simulation using the STM32F407 discovery-development-board as an experimental study.
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Authors and Affiliations

Ali Chebabhi
1
Abdelhalim Kessal
2

  1. Electrical Engineering Laboratory (EEL), Faculty of Technology, University of M’sila, M’sila 28000, Algeria
  2. LPMRN Laboratory, Faculty of Sciences and Technology, University of Bordj Bou Arreridj, 34000, Algeria
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Abstract

Mature males of a wild boar-pig crossbreed, during the long and short day season, were used for the study which demonstrates that the chemical light carrier CO regulates the expression of biological clock genes in the hypothalamus via humoral pathways. Autologous blood with experimentally elevated concentrations of endogenous CO (using lamps with white light-emitting diodes) was infused into the ophthalmic venous sinus via the right dorsal nasal vein. Molecular biology methods: qPCR and Western Blot were used to determine the expression of genes and biological clock proteins. The results showed that elevated endogenous CO levels, through blood irradiation, induces changes in genes expression involved in the functioning of the main biological clock located in suprachiasmatic nuclei. Changes in the expression of the transcription factors Bmal1, Clock and Npas2 have a similar pattern in both structures, where a very large decrease in gene expression was shown after exposure to elevated endogenous CO levels. The changes in the gene expression of PER 1-2, CRY 1-2, and REV-ERB α-β and ROR β are not the same for both POA and DH hypothalamic structures, indicating that both structures respond differently to the humoral signal received.
The results indicate that CO is a chemical light molecule whose production in an organism depends on the amount of light. An adequate amount of light is an essential factor for the proper functioning of the main biological clock.
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Authors and Affiliations

P. Gilun
1
M. Koziorowska-Gilun
2
B. Wąsowska
1
M. Sowa-Kućma
3
K. Kozioł
4
M. Romerowicz-Misielak
4
W. Kordan
2
M. Koziorowski
4

  1. Department of Local Physiological Regulations, Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences in Olsztyn, Tuwima 10, 10-748, Olsztyn, Poland
  2. Department of Animal Biochemistry and Biotechnology, Faculty of Animal Bioengineering, University of Warmia and Mazury, Oczapowskiego 5, 10-719 Olsztyn, Poland
  3. Department of Human Physiology, Institute of Medical Sciences, Medical College of Rzeszow University, Kopisto 2a, Rzeszow, 35-959, Poland
  4. Department of Animal Physiology and Reproduction, Institute of Biology and Biotechnology, Collegium Scientarium Naturalium, University of Rzeszow, Werynia 502, 36-100 Kolbuszowa, Poland
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Abstract

The research paper reviews issues associated with the impact of groundwater flow on soil characteristics and parameters, hence, the entire structure of a building set on it.Water seepage through the ground, building subsoil or structural elements of buildings made of soil affects the soil skeleton and may lead to changes in the arrangement of individual grains relative to each other, i.e., a modified soil structure. Soil solid phase (soil skeleton) deformations resulting from seepage forces are called seepage-induced deformations. The article characterizes typical seepage-induced deformations and specifies a criterion defining the beginning of the phenomenon. The case study involved using data on cracks and deformations in a historic building, as well as water seepage in its subsoil. Seepage was analysed, and zones where the seepage process initiation criterion was exceeded, were determined based on subsoil water level monitoring data. The determined zones coincide with the location of building cracks and scratches and confirm the possible cause behind building damage.
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Authors and Affiliations

Paweł Popielski
1
ORCID: ORCID
Bartosz Bednarz
1
ORCID: ORCID
Tomasz Majewski
2 3
ORCID: ORCID
Maciej Niedostatkiewicz
4
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Building Services, Hydro and Environmental Engineering, Department of Hydro Engineering and Hydraulics, ul. Nowowiejska 20, 00-653 Warsaw, Poland
  2. Gdansk University of Technology, Doctoral School of Implementation, ul. Gabriela Narutowicza11/12, 80-233 Gdansk, Poland
  3. Pracownia Projektowo-Inzynierska [Design and Engineering Studio] Tomasz Majewski, Os. Sierakowskich 9B lok. 3. 82-400 Sztum, Poland
  4. Gdańsk University of Technology, Faculty of Civil and Environmental Engineering, Department of Concrete Structures, Gdańsk, Poland
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Abstract

This paper describes a fiber-based model proposed for computing the nonlinear longitudinal shear distribution in composite steel-concrete beams. The presented method incorporates the accurate stress-strain relationship with strain softening for concrete and bi-linear constitutive relation for structural steel, both in agreement with Eurocodes, however any one-dimensional constitutive relation can be used. The numerical solution for a simply supported beams loaded with the uniform load, concentrated force and both was presented. The results indicate that the highest value of the shear flow for a beam under an uniform load is at the ends and in the one third of the span length and for the point load, the maximum shear is in the proximity of the concentrated force.

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Authors and Affiliations

B. Grzeszykowski
E. Szmigiera

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