The article lists the fi rst applications of the Joseph Monier patent for the construction of reinforced concrete bridges that took place on the Polish lands. The history of the construction of Monier reinforced concrete arch bridges by Biuro Techniczne Arnold Bronikowski & S-ka Inżynierowie in the Kingdom of Poland was described on the basis of written sources, iconography, literature and current records. In particular, these included the bridge on the pond in the Ujazdów Park in Warsaw, the Reformacki Bridge on the Rypinowski Canal in Kalisz, the bridge over the Czechówka River in Lublin and the viaduct along the Karowa Street in Warsaw. The basic technical parameters of these constructions, dates of implementation and current status were specifi ed. The life and professional achievements of engineer Arnold Bronikowski were presented in the context of his constructions, both beautiful and innovative at the time. Three of the engineering objects described in the article survived the ravages of war and remain in use today.
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Purpose: A review of the literature regarding the occurrence of fretting wear in orthodontics and its test methods have been presented. Design/methodology/approach: The influence of micro-movements occurring in the oral cavity on the occurrence of fretting wear in a fixed orthodontic appliance is discussed. The fretting test methods were analysed, taking into account tine shape of the samples and the amplitude of the movements, calculated according to the Hertz contact problem. Fretting-corrosion tests on tines wear of materials are included. Findings: Fretting occurs between the bracket and the orthodontic archwire in a fixed appliance. The test of the amount of wear material mainly uses samples created for the needs of the device. The test of ready-made components of a fixed appliance usually relate to the value of the coefficient of friction. The use of coatings increases the coefficient with the simultaneous reduction of the amount of wear material. Fretting-corrosion occurring in the oral environment has a negative impact on the wear of materials. The value of the total area of abraded material after fretting is unknown. Research limitations/implications: Particles of fretting wear
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W artykule przedstawiono opracowywane obecnie algorytmy obliczeń, które będą wykonywane w programie komputerowym MUGO służącym do wyznaczania przesunięć toru i robót ziemnych. Program jest związany z modernizacją układów geometrycznych toru kolejowego. W pracy scharakteryzowano aktualny stan zaawansowania programu.
EN
The article presents actually developed calculating algorithms used in computer program MUGO. The aim of the program is to consider changes of the curve geometrical layout due to modernization. The paper characterizes the current progress of the program.
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W artykule przedstawiono wyniki badań doświadczalnych przeprowadzonych na pięciu sklepieniach walcowych. Sklepienia wykonano z cegły ceramicznej pełnej układanej na zaprawie wapiennej. Grubość sklepień wynosiła 125 mm. Rozpiętość sklepień mierzona w świetle podpór była równa 2000 mm, a strzałka 730 mm. Obciążenie przekazywane było bezpośrednio do górnej powierzchni sklepień w 1/4 ich rozpiętości. Opisano wyniki badań dwóch sklepień niewzmocnionych oraz trzech sklepień wzmocnionych powierzchniowo kompozytem o matrycy mineralnej zbrojonym siatką z włókien szklanych. Badano sklepienia wzmacniane przy powierzchni grzbietowej lub przy powierzchni podniebienia. Określono wpływ zastosowanej metody wzmocnienia na nośność i schemat zniszczenia sklepień.
EN
This paper presents results of experimental tests on five masonry barrel vaults. The vaults were made of clay bricks and lime mortar. Thickness, internal span and rise of the vaults were 125 mm, 2000 mm and 730 mm respectively. Two of them were tested without strengthening whereas three of them were strengthened with composite material. A glass grid embedded in a cement-based matrix was used. The vaults were strengthened at its extrados or at its intrados. In all tests the load was applied at a quarter span. The main aim of the research was the experimental study of the influence of strengthening on load bearing capacity and failure mechanism of masonry vaults. The influence of strengthening location was also discussed.
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The history of spring construction is chronologically characterized. A description of various mechanisms with elastic elements is presented. Subsequent phases of development are illustrated by examples of inventions in the domain of military and transportation technology, significant to humankind.
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