Analysis of eccentric press shaft of fatigue fractures

The paper presents selected eccentric press stress analysis aspects. This approach is based on the assumption that fractures can be present in the analyzed constructions. Calculations define the current state of the component in view of fracture mechanics. Calculations were performed using analytical, numerical and experimental methods for construction element durability assessment

Virtual testing in terms of pedestrian safety improvements

Pedestrian fatalities in traffic accidents continue to be a significant social burden and pose a costly hospitalization problem. Statistical research conducted in European countries onfirms that pedestrians account for 12-35% of severely injured or illed victims of road traffic accidents. The paper outlines the European test procedure and a pedestrian safety guideline drawn up by the EEVC (European Enhanced Vehicle-Safety Committee). In addition, the emphasis is put on the Virtual Testing regarding the current regulations. The great development of computation power and expansion of Finite Element Method enables to widen the possibilities and application fields including pedestrian safety in terms of a collision with the front of a motor vehicle

Child safety on various bicycle-mounted seats during vehicle impact

This research addresses an important gap in the state of the art by investigating the safety of vulnerable road users – children transported on bicycle seats. The article focuses on three forms of bicycle-mounted child seats and their kinematics during an accident scenario involving a motor vehicle. The front, rear-frame and rear-rack mounted child seat mounting configurations were considered in this study. The research covers the impact of a sports sedan vehicle against a bicycle equipped with the child seat. The assessment of the child safety was done through numerical simulations by coupling the codes of MADYMO and LS-DYNA. The after-impact kinematics for various baby carriers is presented with the emphasis on child’s head and neck injuries. The results were compared to the full-scale test available in the literature. The findings prove a low protection level for the child provided by the bicycle carriers in all considered cases. The study is further devoted to directions of increasing child safety in this means of transportation. First published online 18 March 201

Measurements, Models, Systems and Design

531 s.

Three-dimensional numerical model of heat losses from district heating network pre-insulated pipes buried in the ground

The purpose of the paper is to investigate the challenges in modelling the energy losses of heating networks and to analyse the factors that influence them. The verification of the simulation was conducted on a test stand in-situ and based on the measurements of the testing station, a database for the final version of the numerical model was developed and a series of simulations were performed. Examples of the calculated results are shown in the graphs. The paper presents an innovative method of identify the energy losses of underground heating network pipelines and quantify the temperature distribution around them, in transient working conditions. The presented method makes use of numerical models and measured data of actual objects.The dimensions of the pipelines used were 6m wide, 8m high and 1m in depth, while they were simulated under conditions of zero heat flow in the ground, in the perpendicular to the sides direction of the calculated area and considering the effects of ground's thermal conductivity. The mesh was developed using advanced functions, which resulted its high quality with the average orthogonal quality of 0.99 (close to 1.00) and Skewness of 0.05 (between 0.00 and 0.25). To achieve better accuracy of the simulation model, the initial conditions were determined based on the numerical results of a three-dimensional analysis of heat losses, in steady state conditions in a single moment. The validation process confirmed the high quality of the model, as the differences between the ground temperatures were approximately 0.1°C

Professor Stanisław Borowski as an Economics Historian

Professor Stanisław Borowski, though professionally connected with statistics and demography, stalled his economic activity with research on economic and social history. As a participant of a seminar conducted by Prof. Jan Rutkowski, who was one of co-originators of the science of economic history in Poland, he earned first knowledge on research methods of economic historian. First of all, he learned to- esteem and use in practice principles of closeness and reliability in all scientific undertakings. He stayed true to the principles until the end of this life. After Prof. Rutkowski's death (1949) Stanisław Borowski put forth further scientific activity under direction of the author. The protection turned into a sincere, obliging friendship later on. Scientific output of Professor Borowski is impressive in the scope of economic history. It is mainly devoted to the history of Wielkopolska agriculture and country in the 19th and the 20th centuries. It comprises a few voluminous monographic works, f. ex. a great monographs entitled „Genesis and Labour Conditions of Agrarian Workers in Wielkopolska During Great Agrarian Reforms (1816 - 1860)", the work qualifying for assistant-professorship entitled „Stratification of Wielkopolska Country in the Years 1807 - 1914", numerous minor treatises and articles, methodic studies, papers prepared for scientific congresses and conferences (in which Prof. Borowski participated intensely) and critics of Polish and foreign publications in the scope of economic and social history. All Prof. Borowski's works are based on very profound source data. Owing to wide utilization of statistical methods and stress put on research on social structures they liken the trend represented by the French „histoire quantitative" Unusual dilligence of Professor Borowski won over the common respect for him. The premature death, unfortunately, put an end to his further scientific plans. His voluminous output, however, in the scope of economic history has remained. It occupies a very important place in Polish historiography.Digitalizacja i deponowanie archiwalnych zeszytów RPEiS sfinansowane przez MNiSW w ramach realizacji umowy nr 541/P-DUN/201

Properties of serial-parallel active compensator in renewable energy source and power grid interface

Today in practice for generating electrical energy in energetic grid often are using renewable energy source. For correct electrical energy transmission form the renewable energy source to energetic grid it is necessary apply interconnection system. In a paper are present results of simulation and experimental researches of series-parallel active compensator using as interconnection of renewable energy source and energetic grid