The paper presents analysis of the stress-strain behaviour due to creep in statically determinate composite steel-concrete beam according to Eurocode 2, ACI209R-92 and Gardner&Lockman models. The mathematical model involves the equation of equilibrium, compatibility and constitutive relationship, i.e. an elastic law for the steel part and an integral-type creep law of Boltzmann-Volterra for the concrete part considering the above mentioned models. On the basis of theory of the viscoelastic body of Maslov-Arutyunian-Trost-Zerna-Bažant for determining the redistribution of stresses in beam section between concrete plate and steel beam with respect to time ‘t‘, two independent Volterra integral equations of the second kind have been derived. Numerical metod based on linear approximation of the singular kernel function in the integral equation is presented. Example with the model proposed is investigated. and Obsahuje seznam literatury
Inspired by the work of Sellars, Cumpa (2014, 2018) and Buonomo (2021) have argued that we can evaluate our metaphysical proposals on fundamental categories in terms of their capacity for reconciling the scientific and the manifest image of the world. This criterion of fundamentality would allow us to settle the question of which categories among those proposed in the debate—e.g., substance, structure or facts—have a better explanatory value. The aim of this essay is to argue against a central assumption of the criterion: semantic descriptivism. Specifically, I aim at showing that the criterion rests on the idea that the manifest picture is mostly a description of the world, and thus, it commits us with certain realism. Instead, I argue that at least some of the vocabulary we use to construct our manifest picture of the world, mental vocabulary, is evaluative rather than descriptive and thus creates problems in reconciling the manifest picture with scientific psychology and neurosciences. I conclude with some remarks on alternatives that could provide a way out of the fundamentality criterion.
Examination of 4055 molluscs of 10 species from cenotes (= sinkholes) and other freshwater bodies in the Yucatan Peninsula, Mexico revealed the presence of-larval stages of 13 trematodes. The following species were found: Echinochasmus leopoldinae Scholz, Ditrich et Vargas-Vázquez, 1996, E. macrocaudatus Ditrich, Scholz et Vargas-Vázquez, 1996 (Echi-nostomatidae), Saccocoelioides sp. (? sogandaresi Lumsden, 1963) (Haploporidae), Crassicutis cichlasomae Manter, 1936, pleurolophocercous ophthalmocercaria sp. (Homalometridae), Ascocotyle (Ascocotyle) sp., Ascocotyle (Phagicola) nana Ransom, 1920 (Heterophyidae), Oligogonotylus manieri Watson, 1976 (Cryptogonimidae), Genarchella astyanactis (Watson, 1976) (Derogenidae), xiphidiocercariae sp. 1, 2 and 3 (Lecithodendriidae?), and furcocercaria gen. sp. (Fellodistomidae). The life-cycle of the derogenid Genarchella astyanactis was studied for the first time. It was found that it differs from that of G. genarchella: the first intermediate host, Pyrgophorus coronatus (Pfeiffer, 1839), released cystophorous furcocercariae of G. astyanactis that developed, after ingestion by the second intermediate host, copepods (experimentally Mesocyclops chaci Fiers, Reid, Ilife et Suárez-Morales, 1996), into metacercariae resembling by their morphology juvenile trematodes found in the stomach of Aslya-nax fasciatus. No progenetic cercariae (metacercariae) found in G. genarchella were observed in the life-cycle of G. astyanactis. Rediae and cystophorous furcocercariae were recovered from naturally infected snails and snails experimentally kept in contact with eggs from the uterus of G. astyanactis adults.