This paper presents research on the impact of printing speed on the strength of a manufactured object and is the next stage of the author's research on the impact of technological parameters of 3D printing on the strength of printed models. The tested universal specimens were printed using the FDM (Fused Deposition Modeling) method from PLA (polylactic acid, polylactide). The paper presents the maximum breaking force of the samples and the time of printing samples depending on the printing speed, which varied from 20 mm·s−1 to 100 mm·s−1. The research indicates that the strength of samples decreases with increasing speed. In the range of 50-80 mm·s−1, the strength of the specimens remined at a similar level, however, above 80 mm·s−1, it decreased significantly.
Development investment capacity of farms depends on their potential and scale of production, and thus its revenue, which determines the scale of investment purchases. Most specialized farms have growth potential. Farmers take great interest in modernization and investing in new technologies, machinery and agricultural land, as confirmed by market analysis. Literature references offer information regarding the needs and investment opportunities of territorially diversified farms running conventional production, however the aim of the work is to determine the investment possibilities of organic farms with various production branches. The research included 50 farms certified as ecological producers. In order to answer the question which type of business has the greatest development potential, the examined facilities were divided into branch groups.
The objective of the paper was to determine the costs of production and production effectiveness of pellets made of sawdust and characteristics of logistics of raw material carriage and distribution of pellets. The scope of the paper covered the research carried out in the branch of DREWEX company located in Chotelek town (Świętokrzyskie voivodeship, Province of Busko Zdrój). Unit costs of pellets production were: 513.4 PLN∙t−1 for option 1, 423.3 PLN∙t−1 for option 2 and 393.3 PLN∙t−1 for option 3. The most favourable was option 3 when the pellets were produced on the technology line in the 3-shift system day and night. The average distance to seven cities from which sawdust was delivered was 43.6 km and the distance to which production was distributed to ten cities was on average 105.5 km.
The article presents an algorithm for calculating selected energy assessment indexes for grain driers. Particular attention was paid to the conversion of the equations obtained for the operating conditions of the drying process into equations allowing the calculation of indexes for the standard drying conditions. The indexes obtained allow a proper comparison of dryers operating in varied atmospheric conditions, as well as humidity and temperature of the dried material.
Georgij Tajanowskij, Wojciech Tanaś and Mariusz Szymanek
Conclusions on the analysis of the state of development in the tractor industry are formulated, aspects of the forecasting concept of transformation, general layout solutions and the theory of promising tractor units with new propulsion systems are considered, a general approach to the pre-design substantiation of new generation tractors is presented.
The aim of the work was to determine the influence of screw speed and variable amounts of fresh vegetable additives on selected aspects of extrusion-cooking of corn-vegetable blends. Corn grit as a basic component was supplemented with a fresh pulp of beetroot, carrot, leek and onion in amounts of 2.5-10% in the recipe. The extrusion-cooking was carried out using a single-screw extruder in the temperature range 120-145°C and extrudates were formed into directly expanded snacks. Two indicators were measured: the production efficiency (Q) and the specific mechanical energy (SME) consumption. As a result of the findings it was noted that the rotational speed of the extruder’s screw showed a greater impact on both production efficiency and SME as compared to the variable amounts of applied additives. A tendency to increased efficiency and specific mechanical energy consumption was observed along with the increase of screw speed during processing. The highest production efficiency was observed if fresh leek and onion were used as additives and the highest extrusion speed screw was applied. The largest specific energy consumption was noted during the extrusion-cooking of blends containing fresh carrot and onion addition at high screw speed.
Wojciech Gołębiowski, Grzegorz Zając and Artur Wolak
The paper presents results of research on selected physico-chemical parameters of engine oils from farm tractors based on the date of their change assumed by the user. 17 samples of used engine oil from farm tractors of various producers and with a varied exploitation course were analysed. Oils for research were collected during oil change, registering the service life of oil each time. They were obtained from service points that repair farm tractors in the region of Lublin Province. The studies were to verify whether a decision concerning oil change taken by tractor users after specific time of operation of an engine was good. Number of exceedings of the threshold values of parameters of engine oil which are responsible for correct lubrication were the basis for evaluation
Jarosław Czarnecki, Marek Brennensthul, Włodzimierz Białczyk, Weronika Ptak and Łukasz Gil
The paper presents results of the research on traction properties of two tractor tyres used on two agricultural grounds. The first ground was a stubble and the second one cropland. The investigated tyres had the same structure (diagonal, with a traditional tyre tread but different external dimensions. The research was carried out in field conditions with the use of a stand aggregated with a farm tractor. Analysis covered traction efficiency, slide, towing power and power lost on the rolling resistance and wheel slide. Based on the obtained results it was concluded that on a ground with lower compaction, the values of power losses were higher and traction efficiency was lower. Moreover, it was proved that the value of the power lost for rolling resistance had a decisive impact on the values of traction efficiency
The objective of the paper is to review the present state of knowledge on health threats that occur as a result of some thermal processing of food products. Depending on the type and properties of raw materials and conditions of processes, carcinogenic, mutagen and genotoxic substances may be formed out of them, which may be treated as a process contamination. They are produced in processing plants, where their content is obligatorily controlled and organic, as well as in the conditions of food production in gastronomic units and households. The paper emphasises the second area of food processing, in particular, house-holds and popularised grilling processes, where there are no other possibilities of control of the threat level and awareness of people who prepare food and consumers is insufficient. The paper presents the most often occurring hazardous compounds, the most important regulations and admissible limits of consumption, as well as principles of thermal processing in a safe manner, and possibilities of limiting the levels of those substances in products
Peter Bajus, Miroslav Mraz, Ivan Rigo, Pavol Findura, Adam Fürstenzeller, Pawel Kielbasa and Urszula Malaga-Tobola
Evaluation of harvest and postharvest treatment quality of the grains is affected by usage of appropriate equipment and technology. The grain damage depends on its physical and mechanical features. The corn planting has significant representation in European conditions, mainly for food industry purposes. In the work, we were focused on observing of the drying temperature’s impact on the micro-damage of the seeds. The solution of the issue described in the work is closely related to the preparation and solution of the education project KEGA 039SPU-4/2017, and a scientific research project VEGA 1/0718/17 „Study about the effect of technological parameters of the surface coating in agricultural and forestry techniques for qualitative parameters, safety and environmental acceptability“.