Design of the crusher for plastic and rubber waste produced in automotive industry

According to European Tyre&Rubber Manufacturers' Association (ETRMA), there are about 1 billion cars all over the world. If the interest in cars does not change, the number of cars is going to be increased and in 2030 there is going to be more than 2 billion cars in the world - regardless of whether they will be powered by a petrol engine or a completely different one at that time. Based on the studies, we focused on the design of the crusher whose task is to effectively recover plastic and rubber waste from used cars. The paper describes the stress - strain analysis of the cutting device of the crusher using a defined material for its production. The basic parameters of the crusher were investigated for a determined final cutting force. Based on the cutting force and the designed crusher, a finite element analysis (FEM) was performed confirming the correctness of the selected material for the production of the crusher for the processing waste materials. The basic parameters of the crusher were observed for determination of the final cutting force.

Planning and regulation of pre-final cuttings in Poland – a proposal for change

Scheduling and regulation of the forest use are of much importance in forest management. Decisions regarding the manner, timing, and intensity of tree felling result in long-term effects, as these affect the species and age structure of forests, along with the direction and dynamics of changes in forest resources. Above all, serious doubts concern the way of determining and accounting for the prescribed forest utilization, and in particular, the possibilities of the pre-final cuttings. In recent times, the precise determination of the pre-final cuttings by volume has been given up. According to the law, the area of pre-final cuttings is now obligatory taken into account. Consequently, it is not possible to determine the total volume limiting the amount of timber to be harvested, thus, there is decreased the value of the forest management plan as the document approved by the minister responsible for forestry as well as the basis for forest management. For practical reasons, the specified pre-final cuttings by volume are considered as indicative. Connecting the planned pre-final cutting volume with the expected volume increment of the stand has not been relinquished. In the present paper, the authors called attention to a necessity for further improvement of the medium-term planning of pre-final cutting volume. A need to change the definition of the incidental cutting was emphasized. As said by the authors, the term “incidental cutting” should denote harvesting wood from diseased and dying or dead trees, along with eliminating the effects of tree damage caused by fortuitous events. Accordingly, the incidental cuttings that are inherently unpredictable, should not be directly attributed to pre-final cutting products. Keeping in mind the incidental cuttings, the authors proposed the method of reckoning the forest use, which would allow for correct accounting with regard to the prescribed pre-final cuttings.

A Preliminary Microbiological Assessment of Process Hygiene of Traditional Outdoor Camel Slaughter in Sahrawi Refugee Camps†

The aim of this study was to investigate the hygiene performance of a camel (Camelus dromedarius) slaughtering process as carried out with the traditional method in the Sahrawi refugee camps located in southwestern Algeria. The camel slaughtering process in this region differs significantly from that carried out in commercial abattoirs. Slaughtering is performed outdoors in desert areas, and dehiding of the carcass is approached via the dorsoventral route rather than the classic ventrodorsal route. Samples were taken from 10 camel carcasses from three different areas: the hide, the carcass meat immediately after dehiding, and the meat after final cutting. Enterobacteriaceae counts (EC) were enumerated employing conventional laboratory techniques. Carcass meat samples resulted in EC below the detection limit more frequently if the hide samples from the same carcass had also EC counts below the detection limit. Because of the low number of trials, the calculation of statistical significance of the results was not possible. Further experimental research is needed in order to validate the results presented in this study. The comparison of the microbiological hygiene performance between dorsal dehiding and traditional ventral dehiding of slaughtered animals could serve to validate the hypothesis of the potential positive impact of the dorsal dehiding method in carcass meat hygiene.

Forest yield index and its applicability to the assessment of future forest yields

The paper suggests and examines a simplified relative indicator of forest production, with special regard to possibilities of its use in projecting future forests. Forest yield index (<I>I</I>_Y), based on an economic parameter “value of final cutting yield” was proposed, and examined in the model territory of Kysuce in north-western Slovakia. The current values of final cutting yield, dependent on tree species, site index and the length of rotation period served as a basis for the assessment of expected yields. The possibilities and limitations of index applicability in long-term strategic forest management decision-making are discussed, considering the uncertainty of ecological and economic conditions during the long forest production cycle, as well as the complexity of tree species growth and production in the mixed forests, uneven aged forests and forests under climate change.