Michal Dubovský

ABSTRACT Nowadays, the airline industry and worldwide companies in the aerospace industry have been forced to find new ecological alternatives to traditional fuels to substitute as aviation fuels and kerosene. In aero turbo engines, rubber seals based on nitrile–butadiene rubber (NBR) with different contents of acrylonitrile are the most commonly used for the production of seals. This NBR is characterized by excellent physical and mechanical properties. In this article, we present the effects of critical operating conditions and the addition of the methyl ester of rapeseed oil to aviation fuel in relation to seals for aircraft engines. In this study, we evaluated changes in the physical and mechanical properties of rubber blends that were produced from NBR rubber. The exact composition and material properties were obtained from the producer. Static immersion tests in B10 (10% biodiesel in diesel), B50 (50% biodiesel in diesel), B75 (75% biodiesel in diesel), and B100 (100% biodiesel) were carried out at a higher temperature (100°C) for 500 h and at laboratory temperature (23 ± 2°C) for 3000 h. At the end of the immersion test, the degradation behavior was investigated by the measurement of the relative changes in the weight, hardness, tensile strength, and elongation. The change in the rubber surface morphology was studied by optimal microscopy and with a digital camera. The results show that the extent of rubber blend degradation was observed for samples that were exposed to a higher concentration of biodiesel and to a higher temperature. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42254.

Barley thrips, Limothrips denticornis, Haliday, 1836 (Thysanoptera: Thripidae), a grass-dwelling Holarctic species represents a model example to study transport mechanisms of Thysanoptera into nests. In samples from more than 1,500 nests, barley thrips were recorded in nests of 20 vertebrate species, both birds and mammals. Applying appropriate statistics (nonparametric methods) clear clustering among nest materials and a strong relationship between presence of thrips and grass as the nest material was found. Occurrence of thrips was not associated with nest size, location or height. To validate our statistical analyses 15 wooden boxes were installed and equipped with sticky traps to record the whole year migration dynamics. Barley thrips infiltrate nests by various ways (e. g. dwelling on bark, landing from atmosphere), however most of them (88%) invade passively on nest material (grass) in spring (1st summer nesting) and autumn (winter nest building).

Abstract Three spare modules of the ATLAS Tile Calorimeter were exposed to test beams from the Super Proton Synchrotron accelerator at CERN in 2017. The detector’s measurements of the energy response and resolution to positive pions and kaons, and protons with energies ranging from 16 to 30 GeV are reported. The results have uncertainties of a few percent. They were compared to the predictions of the Geant4-based simulation program used in ATLAS to estimate the response of the detector to proton-proton events at the Large Hadron Collider. The determinations obtained using experimental and simulated data agree within the uncertainties.

Abstract The COVID-19 pandemic represents one of the most significant healthcare challenges that humanity faces. We developed a stochastic, individual-based model of transmission of COVID-19 in Slovakia. The proposed model is based on current clinical knowledge of the disease and takes into account the age structure of the population, distribution of the population into the households, interactions within the municipalities, and interaction among the individuals travelling between municipalities. Furthermore, the model incorporates the effect of age-dependent severity of COVID-19 and realistic trajectories of patients through the healthcare system. We assess the impact of the governmental non-pharmacological interventions, such as population-wide social distancing, social distancing within specific subsets of population, reduction of travel between the municipalities, and self-quarantining of the infected individuals. We also evaluate the impact of relaxing of strict restrictions, efficacy of the simple state feedback-based restrictions in controlling the outbreak, and the effect of superspreaders on the disease dynamics. Our simulations show that non-pharmacological interventions reduce the number of infected individuals and the number of fatalities, especially when the social distancing of particularly susceptible subgroups of the population is employed along with case isolation.

The aim of the study is to determine the valence and collocational links and relations between the units of English-language and Russian-language multi-component attributive phrases. The scientific novelty of the study lies in systematising the theoretical and practical knowledge within the theory of the combination of linguistic units in relation to the analysis of multi-component attributive phrases in English and Russian, assessment of their valence potential and its manifestation through specific combinations. As a result, it has been found that valence and collocability in multi-component attributive phrases in the compared language formats are recorded primarily at the syntactic, lexical and semantic levels. Various forms of collocability emerge between the units of attributive construct with active and passive valence, such as formal and conceptual, arbitrary and conditioned, contact and distant, intrinsic and extrinsic, open and closed, absolute and relative, stylistic, emotionally expressive, associative proper, ontological and cognitive-semantic. By taking into account collocability, it is possible to penetrate deeper into the structure of multi-component attributive phrases and factor in their nature when analysing the linguocreative activity of the speaker.

Introduction. Corrosion damage of reinforcement and concrete is an important factor reducing durability of industrial facilities. The article presents the methodology and results of probabilistic calculation of residual life of separate reinforced concrete structures of an industrial building as well as of reinforced concrete structures working in the system. A three-storey open stand with dimensions in terms of 30 × 15 m and 25 m in height is considered. The calculated parameters of the actual state of the structures are obtained on the basis of experimental diagnostic studies.
 
 Materials and methods. According to the results of a full-scale field engineering inspection using standard and non-standard methods of non-destructive testing, the most damaged structures of the framework — reinforced concrete floor beams have been determined. The degree of corrosion damage of working reinforcement and compressed concrete has been determined. The method of probabilistic calculation of a reinforced concrete beam with regard for corrosion deterioration is outlined. The limiting bending moment in the beam section is considered as a nonlinear function of two random arguments — the strength of concrete and the strength of reinforcement. A linear law of corrosion damage accumulation is adopted. The probabilistic characteristics of the limiting bending moment are found by the Monte Carlo method on the basis of the normative method of calculation of a rectangular reinforced concrete section with double reinforcement. The reliability index has been used to determine the numerical values of the probability of failure and operating time.
 
 Results. Statistical characteristics of bending moment limit changing in time from the beginning of concrete protective properties exhaustion to element failure have been obtained. Lifetime before failure for a given guaranteed safety is found out.
 
 Conclusions. The practical application of the probabilistic method combined with field survey data to solve the problem of assessing the residual service life of reinforced concrete beams of a real industrial building is shown.

Abstract The article presents the studies’ results on the safety characteristics of the most damaged load-bearing structures in a monolithic reinforced concrete building. Reliability assessment was carried out at the stage of putting the building into operation. The analysis of the numerical reliability characteristics is carried out taking into account design and actually implemented strength parameters of the considered structures.