Volumen 23 (2019): Heft 1 (March 2019)

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“.

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 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

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

Paper presents research concerned utilization of natural gas in a liquid state as a new source of electrical energy generation in country side areas of Russia to use it in a small family farms and bigger agriculture enterprises. The experiment shows that alcohol and gasoline are more expensive products to be a source for electricity generation as a reserve energy supply in agriculture production areas of the country. Introduction of natural gas generator as an alternative fuel makes possible to produce low cost of electrical energy in any part of the country, what gives great potential to alternative energy supply, but especially for agriculture production on small households and also bigger enterprises

The second-generation liquid biofuels are fuels derived from non-food raw materials, i.e. waste cooking oils and animal fats. They are waste raw materials from the agri-food industry, hence their quantity is limited, and their quality depends, inter alia, on the place of their acquisition. Considering the fact that rheological properties of liquid biofuels are closely correlated with the quality of raw materials from which they are obtained, the industrial production of biofuels from waste fats requires development of new analytical methods, allowing for a quick assessment of the quality of the obtained products. The aim of the study was to confirm the possibility of using near infrared spectrometry to assess the content of methyl palmitate in biofuels produced from waste cooking oil. The calibration models were based on 41 absorbance spectra recorded in the range of 400-2170 nm for samples containing from 0 to 5 % of methyl palmitate. The obtained results confirmed that there is a possibility of effective detection of the concentration of this ester in biofuel using the spectrum in the range of 1644-1778 nm. The developed PLS calibration models are characterized by a determination co-efficient (R²) exceeding the value of 0.99.

The paper presents kinetics of osmotic dehydration of plums in relation to the treatment time and concentration of sucrose solution. The main aim of the study was polyoptimisation of the preservation process, namely selection of optimal parameters of osmotic dehydration processes including changes in selected quality indicators. Defining of optimal conditions of the entire course of preservation may influence limitation of consumption of preserving substances (osmotic substances) and reduction of the energy demand. Based on the research which was carried out, it was found that parameters of osmotic dehydration had a significant impact on mass transfer coefficients and physico-chemical indicators of fruit - along with the increase of concentration of osmotic solution and extension of the time of the process, the increase of the investigated sizes was observed. In the second part of the paper, optimization of the fruit preservation process was performed. The idea of the objective function consisted in minimization of the difference between the expected values of criteria and the values obtained from the experimental results. For the defined scalar optimization criterion an explicit relation between quality and cost of the product was showed.

Currently in Russia and other countries in family farms there is a demand for lowering cost of animal production. Main direction to achieve new terchnological solutions characterized by low energy constumption and high efficiency with maintaining high quality of product (mineral). For example, lately in animal production are acquired concentrates with low unity costs. Realising targets releated with lowering costs of forage production with usage comminution and crease of grain. Previously conducted own researches and literature analises shows, that currently used solutions are characterized by big errors made by construction of the devices, and technology effect of obtained product (grain). The paper presents the criteria for optimalization of technical indicators of shredding devices affecting the quality of the product.

The paper presents a concept of determination of pre-compression stress. It assumes that the stress value is close to the unit pressure value which is indispensable to increase the initial degree of soil compaction. Thus, an attempt was made to develop an empirical model for predicting the value of stress at which the initial compaction of a soil sample increases by a determined value. Samples with the so-called intact structure (NS) and soil material in the form of loose mass were collected from subsoil, and they were used to form model samples. Both types of samples were uniaxially compressed. For the study, data on moisture and dry bulk density of model samples were used, as well as determined ratios (conversion factors) that present relations between the results of compaction of model samples and samples with the intact structure. It was reported that the pressure necessary for the increase of the initial compaction of the model samples with the value of +0.05 or +0.10 g∙cm⁻³ were higher than the formation pressure respectively by 1.03-1.11 and 1.42-1.93 times. It was proved that for determination of the pre-compression stress of the NS samples models of linear regression for prediction the pressure needed to increase the initial compaction of the model sample by the value of +0.05 g∙cm⁻³, combined with a coefficient calculated for the present state of the soil properties, can be applied.

A liner is the only part of the milking unit which has a direct contact with a cow’s teat. It ensures a correct circulation of body liquids in a teat with its suitable massage and creates conditions for a teat to open and milk to flow out and maintains a milking cup on a teat. The result of the last task is generation of a suction force that sucks a teat into a liner. During milking, when a cup is placed on a teat, counter forces are generated that try to remove a liner from a teat and forces that cause that a teat moves up to a liner producing a phenomenon of “a climbing cup”. Forces that tend to separate a teat from a liner depend on the mass of a milking cup set and the value of the friction force. A counter force that tends to suck a teat into a liner is proportional to the level of negative pressure in a liner and the surface of cross-section of a teat that is subjected to negative pressure. We should also assume that also the structure of a liner will influence this force. The paper presents results of the laboratory tests on the impact of the shape of the cross-section of a rubber core and construction solutions of liners on the vacuum force of a liner when a teat is sucked into a teat chamber. Eight liners, popular in milking machines used in our country were used in the tests. Various penetrations of a teat (50, 62, 75 and 100 mm), working pressure (25-55 kPa) and a working stage of the milking cup were additional variables. In order to determine whether and what is the degree of the impact of variability sources on shaping the suction forces of a liner, a static processing of results was carried out using a multi-variance analysis. It was proved that at the significance level of α=0.05, the source of variability assumed in the experiment in the form of the liner shape, negative pressure and penetration affected the analysed sizes, i.e. Average values of suction forces in the suction phase (F_ws) and massage phase (F_wm). The investigation of the impact of the rubber core part on the determined values of the suction force in the function of variable negative pressure proved that at teat penetration of 50 and 62 mm (the most popular lengths of teats in milked cows), the lowest suction force was observed in case of a liner with a triangular cross-section, slightly bigger with a square cross-section and the highest suction force is generated by round and oval liners.