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Currently, composite resins are used in many restorative procedures. Previous studies showed that drinking beverages may affect the mechanical properties such as microhardness or flexural strength of dental composite resins. The aim of the present study was to investigate the influence of common beverages on the mechanical properties of composite resins. Samples of the materials were prepared according to the ISO 4049:2010 standard and producer’s recommendations. The samples were next conditioned in tested fluids: distilled water, sparkling water, Coca-Cola, Red Bull and orange juice for 7 days. Vickers microhardness and flexural strength testing was performed after 7 days. Performed statistic tests confirmed the significance of microhardness changes of the tested materials in terms of both different conditioning of the samples and different composite materials. The mean flexural strength of composites was highest in distilled water and it was reduced after one week in different beverages. We conclude that all tested beverages influenced on Vickers microhardness of tested composite resins. Flexural strength only in one material was statistically significantly influenced by tested beverages. The results of this study should be taken into consideration by a dentist preparing recommendations for the patients after dental treatment with usage of composite material or after cementing composite based fixed dentures.

Indoor navigation and vehicle tracking require special measurement techniques. The reference points and routes used by classic AGV (Automated Guided Vehicle) systems are usually buried under floor surface or painted directly on the floor, thus limiting the set of possible transportation paths. However, the indoor environment of an industrial warehouse is dynamic, the number and location of objects inside are subject to frequent changes and these changes might not be reflected in the map of the area. In such conditions, navigation according to the on-board instruments (dead-reckoning) could provide valuable information about the position and orientation of the vehicle. This paper reports test results from a smart sensor using a 6-axis MEMS IMU unit and a self-calibrating procedure for indoor vehicle orientation tracking. The smart sensor, integrated with information from wheel encoders can produce 2D position coordinates suitable for navigation. Original data processing algorithm, applied in the sensor, was developed by the authors as a part of the research project on mobile robotics.

Searching for new ways to utilize rubber and polymer waste has been the focus of many studies conducted by research centers and companies worldwide. In this study, the influence of extrusion conditions on the properties of thermoplastic compositions containing post-production recycled high density polyethylene (PE-HD) and ground tire rubber (GTR) at 50:50 mass ratio was examined. Response Surface Methodology (RSM) was used to determine the effects of the barrel temperature (160-240 °C), screw speed (250-650 rpm) and feed rate of extrusion (1-2.5 kg/h) on the quality of the obtained products. Empirical models for determining the relationship between extrusion conditions, mechanical properties and the mass flow rate of obtained thermoplastic compositions were developed. It has been determined that tensile strength, elongation at break, hardness and the mass flow rate of thermoplastic compositions depend mainly on the barrel temperature. Properties of PE-HD/GTR blends deteriorated with increased barrel temperature, which was due to degradation of polyethylene and reclaiming of ground tire rubber. In studied extrusion conditions the influence of screw speed and feed rate on the properties of recycled high density polyethylene/ground tire rubber compositions was negligible.

The article presents some of the research on the wider work related to testing and improving a new rotary cleaning device. The new cereal grain cleaning and separation device can support the development of sustainable agriculture in terms of seed purity and quality. This device is especially useful for small and medium-sized farms. This device has the characteristics of a multi-stage screen aided by an air stream (i.e., by pneumoseparation). The prototype was constructed at the University of Life Sciences in Lublin. The research was conducted at a test stand, which allowed changes in the operating parameters of the cleaner and their measurement. The scope of the tests included determining the influence of the inclination angle of the sieve unit (α) on the effectiveness and efficiency of oat grain cleaning. The experiment was carried out using two rotational spindle speeds: 5 and 75 rpm. The quality of the separation and cleaning of oat grains was evaluated using six cleaning process parameters: plump grain mass separation coefficient (Spg), fine grain separation coefficient (Sfg), fine impurities separation coefficient (Sfi), chaff separation coefficient (Sch), total coefficient of cleaning effectiveness (E), plump grain cleaning efficiency (qpg). Results showed the significant effect of the sieve drum inclination angle on the efficiency and effectiveness of oat grain cleaning.

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