Minimizing last mile delivery costs is of paramount importance for all shipping companies that strive to stay competitive on the market. A potential solution to the problem is the use of crowdsourcinga model where individuals voluntarily take on a task proposed by another entity (e.g. a company). In this paper, we present the results of a comparison of performance for three types of crowdsourced delivery fleets likely to be used in an urban setting. The fleets differ in the mode of transport the couriers use: bicycles, cars or both. The performance is quantified by the total number of deliveries made and the on-time delivery rates. Experimental results were obtained through a simulation that closely resembles real-world traffic conditions in a city with developed cycling infrastructure and takes into account the variations in the speed of couriers. The research shows that bicycle-based crowdsourced fleets outperform other kinds of fleets under simulated conditions. This makes them a faster, more environmentally-friendly and potentially cheaper alternative to traditional fleets that rely on cars.

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On average, approximately 22 thousand tons of new lubrication oil were marketed annually in Serbia in the period 2015–2019. Less than 20% of the waste lubrication oil (WLO) generated was treated, whereas the remainder was mostly uncollected or improperly disposed of. The purpose of this study is to examine different WLO management scenarios that could be implemented in Serbia in the future and to quantify their potential environmental benefits. Different WLO treatment processes (namely the re-refining of used oil for base oil recovery, the use of WLO as a substitute to fossil fuels in cement kilns, and the combustion of WLO in waste incinerators with energy recovery) were evaluated using the life cycle assessment (LCA) and ReCiPe 2016 impact assessment methods. The LCA results obtained indicate that no single WLO treatment process consistently exerts diminished environmental impacts according to all the impact categories considered. From a human health perspective, the incineration of WLO in waste incinerators was found more favourable than the other treatment processes considered, whereas the combustion in cement kilns was the most favourable approach with regard to ecosystem protection. In terms of fossil fuel savings, re-refining technologies performed slightly better than the other processes considered. This can be accounted for by significant amounts of marketable co-products generated in the re-refining process, which can be used as a substitute to fossil-based primary products. Furthermore, a total of four possible WLO management scenarios were developed on the basis of the annual quantities of untreated WLO and a mix of treatment options. The results obtained indicate that up to 22,100 t CO2 equivalent and 34,300 t oil equivalent could be saved annually in Serbia provided the most favourable WLO management scenario is considered.

The paper analyzes the problem of friction stir welding (FSW) technology. The mechanism of thermo-mechanical process of the FSW method has been identified and a correlation between the weld zone and its microstructure established. Presented are the basic analytical formulations for the definition of temperature fields. Analysis of influential parameters of welding FSW technology at the zone of the weld material and mechanical properties of the realized joint was performed. Influential welding parameters were defined based on tool geometry, technological parameters of processing and the axial load of tool. Specific problems with the FSW process are related to gaps (holes) left behind by a tool at the end of the process and inflexibility of welding regarding the degree of variation of material thickness. Numerical simulation of process welding FSW proceeding was carried out on the example of Aluminum Alloy (AA 2219) using the ANSYS Mechanical ADPL (Transient Thermal) software package. The defined was the temperature field in the welding process at specified time intervals.

The purpose of this paper is to evaluate the relations of originality, efficiency, conformism, and entrepreneurial potential. The sample consisted of a student population from Serbia and Bosnia and Herzegovina as EU candidate countries and from the EU member country, Belgium. Research results can help policy makers receive valuable information on how to improve student attitude towards entrepreneurship. Data was collected from a sample of 1008 university students from these three countries. The Kirton Adaptation Innovation Inventory (KAI), Questionnaire on Entrepreneurial Traits (QET), and The Scale of Entrepreneurial Potential (SEP) were applied in the research in order to obtain data. Canonical correlation analysis revealed a significantly strong relation between originality, efficiency, conformism, and dimensions of the Entrepreneurial Traits model, as well as significant relation to the entrepreneurial potential model. Findings from this study may provide data that could be used to develop and foster the entrepreneurship potential of students and help improve the economy in the region.