Purpose. Female runners are known to be at greater risk from chronic running injuries than age-matched males, although the exact mechanisms are often poorly understood. The aim of the current investigation was to determine if female recreational runners exhibit distinct limb and joint stiffness characteristics in relation to their male counterparts. Methods. Fourteen male and fourteen female runners ran over a force platform at 4.0 m · s -1 . Lower limb kinematics were collected using an eight-camera optoelectric motion capture system operating at 250 Hz. Measures of limb and joint stiffness were calculated as a function of limb length and joint moments divided by the extent of limb and joint excursion. All stiffness and joint moment parameters were normalized to body mass. Sex differences in normalized limb and knee and ankle joint stiffness were examined statistically using independent samples t tests. Results. The results indicate that normalized limb (male = 0.18 ± 0.07, female = 0.37 ± 0.10 kN · kg · m -1 ) and knee stiffness (male = 5.59 ± 2.02, female = 7.34 ± 1.78 Nm · kg · rad -1 ) were significantly greater in female runners. Conclusions. On the basis that normalized knee and limb stiffness were shown to be significantly greater in female runners, the findings from the current investigation may provide further insight into the aetiology of the distinct injury patterns observed between sexes.

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Volatile organic compounds are released during 3D printing, which can irritate the throat mucosa, cause cardiovascular disease and even, in extreme cases, cause a stroke. The survey research was carried out regionally, in the Greater Poland area, with students and lecturers of Poznań University of Technology. The survey was conducted in October and November 2021 among 31 students and 4 lecturers. Students in their third year of engineering studies in Mechanics and Machine Design, Mechatronics, and Biomedical Engineering who are interested in 3D printing have contact with additive manufacturing, personally print on their printers at home or at someone else’s, or submit their projects for printing outside. The survey showed how long, how often and from what materials the items are most often printed. The survey also showed that over 60% of respondents keep the printer in a room where they spend most of the day or sleep. A simulation was made of how contaminants were extracted from the printer when opening the door during or just after additive manufacturing. The tests were carried out in the ANSYS Fluent 2021 simulation environment. Three experiments were carried out, which show how the contamination, depending on the density, circulates around the printer operator and how quickly it spreads around. It has been identified that the operator, in less than 3 s after opening the door, is exposed to the pollution previously accumulated inside the chamber. The pollutants emanating from the chamber take the form of a cloud surrounding the operator’s head.

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In this paper, the application of multi-agent system to support decision-making process in design for recycling is presented. The design for recycling term is highlighted either as the design problem or from the point of view of regulations. The structure of agent system supporting the designer during the design process is showed. The basis of special kind of product model, that is the extension of standard 3D product model, called recycling-oriented product model, is described. The example results of analysis, based on real household appliance model, are presented.