The paper deals with the variability of mechanical properties of EPSTAL steel rods produced in Polish steelworks, i.e. yield stress Re, tensile strength Rm, and elongation Agt. Our study is based on fundamental engineering static room-temperature tensile tests for large series specimens which have been made by manufacturers as the part of a factory quality control. Statistical analysis of these results shows that the stressstrain relationship of steel tensile tests should be described by a one-dimensional stochastic process, and three the most important mechanical parameters, i.e. the yield stress, tensile strength, and elongation by random variables. Based on the statistical elaboration of experimental data, it was found that the yield stress and tensile strength of steel rods produced in the years 2016-2017 had the coefficients of variation of less than 3%, and there is a reasonable basis for the manufacturer to increase the characteristic value of EPSTAL steel rods yield stress by a few percentages.
Czujniki skonstruowane przez polskich inżynierów pomagają wykrywać ślady żywych organizmów w kosmosie. O tym, co jeszcze potrafią, opowiada dr Adam Piotrowski, prezes zarządu Vigo System.
The paper presents general solutions for fractional state-space equations. The analysis of the fractional electrical circuit in the transient state is described by the equation of the state and space equations. The results are presented for the voltage of a capacitor and current in a coil, for different alpha values. The Caputo and conformable fractional derivative definitions have been considered. At the end, the results have been obtained.
An analysis of a given electrical circuit using a fractional derivative. The statespace equation was developed. The dynamics of tensions described by Kirchhoff’s laws equations. The paper used the definition of the integral derivative Caputo and CDF conformable fractional definition. An electrical circuit solution using Caputo and CDF defini- tions for rectangular with zero initial conditions was developed. The results obtained using the Caputo and CDF definitions were compared. The solutions are shown for capacitor voltages, for fractional derivative orders of 0.6, 0.8, 1. The results were compared using graphs.
W 1900 roku, na II międzynarodowym kongresie matematyków, wybitny matematyk niemiecki David Hilbert, ogłaszając listę 23 ważnych problemów do rozwiązania, snuł wizję matematyki jako nauki uniwersalnej, pewnej i oczywistej, która rozwiąże każdy problem. Była to odpowiedź uczonego na III kryzys podstaw matematyki. Rodzi się jednak pytanie o to, czy ocena ta odnosi się do matematyki dzisiejszej. Celem mojego artykułu jest nawiązanie do badań tzw. klasycznych kierunków filozofii matematyki (formalizm, intuicjonizm, logicyzm), zwrócenie uwagi na znaczenie twierdzeń K. Gödla dla rozwoju filozofii matematyki oraz na powstanie nowych nurtów (kierunek kulturowy, quasi-empiryzm, społeczny konstruktywizm, etnomatematyka), nadto uwzględnienie tendencji zachodzących w najnowszej nauce i filozofii matematyki, jak i wskazanie na niektóre cele i zadania stojące przed „nową filozofią matematyki”.
The study presents the results of theoretical investigations into lateral torsional buckling (LTB) of bi-symmetric I-beams, elastically restrained against warping at supports. Beam loading schemes commonly used in practice are taken into account. The whole range of stiffness of the support joints, from free warping to warping fully restrained, is considered. To determine the critical moment, the energy method is used. The function of the beam twist angle is described with power polynomials that have simple physical interpretation. Computer programs written in symbolic language for numerical analysis are developed. General approximation formulas are devised. Detailed calculations are performed for beams with end-plate joints. Critical moments determined with programs and approximation formulas are compared with the results obtained by other researchers and with those produced by FEM. Very good accuracy of results is obtained.
This article takes as its starting point the Greek term μεταξύ, a preposition meaning ‘between’, first turned into a noun in Plato’s Symposium, and in that substantivized form adapted for their own ends by a number of 20th-century philosophers, most notably by Simone Weil. In her Gravity and Grace (French: La Pesanteur et la grâce) she defines le metaxu as in-betweenness, a social and metaphysical category which embraces all that connects and divides (as, for example, a wall that both separates two prisoners and can be used by them to tap messages). In this article Weil’s concept of metaxu is applied to the language and then to various readings of two of Wisława Szymborska’s poems, ‘Funeral’ and ‘Elegiac Calculation’. Pragmalinguistics and semantics, too, play a role in the interpretation of these poems.
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