Volume 21 (2017): Edizione 1 (March 2017)

The paper evaluates operation of the separation unit of NH CR9080 combine harvester. A considerable technical and technological progress has taken place in presently used harvesters. Among others, efficiency increased and equipment has been enhanced with elements which improve the operation quality. The objective of the paper was to determine the quality of the separating unit of a combine harvester New Holland CR9080. During the research, losses on screens and rotor, cutting height of rapeseed, mowing speed, rotation of fans, rotors and engine were determined. Relation of losses on screens to combine operation parameters was determined with a model of multiple regressions. The rotational speed of rotors, mowing speed and rotational speed of the combine engine have a significant effect on losses on screens at the rapeseed harvesting with the investigated combine.

The objective of the paper was to verify previously obtained results of research on the impact of the plate diameter on the determined value of pre-compaction stress of soil (NG) with a wider selection of dimensions of samples. Tests were carried out on samples with a diameter (D) of 100 mm and heights (H) of 30, 50 or 100 mm produced from the soil material (M) or collected (NNS) from subsoil with the granulation group of: silt loam, loam, sandy loam, sandy clay loam. The following soil properties were determined: granulation type, density of the solid phase, content of humus and calcium carbonate, reaction, plastic and liquid limit. Properties of samples were described with moisture, dry density of solid particles, porosity of aeration, degree of plasticity and saturation. Samples were loaded with plates of varied diameters. The NG value was calculated with the method of searching for the crossing point of tangents with the secondary stress curve and the virgin stresses curve (a traditional method). It was stated that the plate diameter (d) and sample height (H) do not influence the measurement results when the relation d/D is within 0.5 ≤ d/D ≤ 0.8 and the ratio D/H equals 2. It is possible to omit the condition d/D in a situation when soil is low cohesive and its degree of moisture is ca. 0.41-0.44.

The paper analyses technical equipment of the selected dairy farms. Data from questionnaires carried out in 96 farms in 2015 constituted a research material. Municipalities Lszewo-Borki in Mazowieckie Voivodeship were covered by the survey. A survey questionnaire, which consisted of two parts, was a research instrument. The first concerned general information on a farm and its owner, and the other consisted of eight questions on technical equipment used for breeding dairy cows. The research allowed to determine that farmers assessed the condition of their machinery park as average (50%) or good (40%). One out of ten farmers claimed that the used machinery park in a farm is in a bad condition. Majority of respondents have allotted from PLN 20 to 50 thousand for investments related to enhancement of a machinery park within the last 5 years. On the other hand, a considerable part of farms allotted up to PLN 20 thousand for development of a machinery park. The investigated group included also farms, which allotted more than PLN 500 thousand for development of a park.

The objective of the study was to determine the effect of extrusioncooking conditions (moisture content and screw speed) and recipe formulation on process efficiency and energy consumption during the extrusion-cooking of gluten-free rice-legumes products, shaped for spaghetti-type pasta. Process efficiency (Q) was determined through measurement of the pasta weight and energy consumption was determined using specific mechanical energy consumption (SME). According to the obtained results, screw speed had a great significant impact on Q and SME values which increased as screw speed increased. Moisture content of raw materials had also a significant effect on Q and SME mainly at low screw speed applied. The process efficiency increased with the increase of raw materials moisture content while reverse observations were noted for the energy consumption. On the contrary, variations of recipe formulations did not affect the measured parameters.

The object of the research consisted of a roller threshing unit with a profile elastic working surface of a parabolic type and a triangle one with rollers which turn concurrently with various angular speeds. Two rollers with 150 and 300 mm were investigated. The process of seeds separation from the threshing mass took place at its moisture of 10 to 35%. The relation of mixtures in the straw mass in a mass relation was changing within 10 to 35% with the length of stalks from 20 to 400 mm. The amount of the material provided for threshing was varied from 0.27 to 0.52 kg∙s^-1∙m^-1 and the slot between the rollers from 1.0 to 6.0 mm. The width of the base of notches located on the working surface of drums was within 25 to 150 mm, the height of notches on rollers was within 10 to 60 mm. Kinematic conditions of rollers operation were within 1.0 to 1.5. As a result of the research it was determined that a parabola is the optimal form of the profiled surface of rollers in a cross section. It ensures more effective seeds separation than a triangle configuration of drums. This conclusion is also confirmed by a theoretical discussion and is explained with the fact that the parabolic form of notches has a bigger surface than the triangle one and that they affect more seed-bags which leads to the increase of the seeds separation degree. The laboratory research allowed determination of rational ranges of parameters changes during flax mass threshing.

The objective of the paper was to investigate the moisture change ability of bean, broad bean, pea, lupine, radish, beetroot, winter wheat, maize, cucumber, pumpkin and sunflower seeds. Seeds absorbed water in the system for measurement of the water absorption kinetics with the capillary and weighting method. The research results were presented in the form of plots of the relation of kinetics of the moisture change of seeds in the time for the first and second stage of the process which precedes germination. Moreover, the water content in seeds for the time of the end of the second stage of water absorption was determined and the maximum water absorption speed coefficient and the time of its obtaining was calculated. The water content for the end of the 2nd stage of its collection was the highest for seeds which include a hard caryopsis and for broad bean plant seeds. The maximum water absorption speed coefficient was the highest for seeds with low initial moisture - radish, beetroot, cucumber and pumpkin. The measurement of the water absorption speed with the use of the capillary and weighting method enabled investigation of seeds with a varied size, construction of a seed coat and chemical composition for a long period of time to the moment seedlings were obtained.

Research on the selected population of students with a standardized questionnaire method concerning the use of IT technologies has been carried out since 2008/09. Results for the data from the first and the last year of research (2009 and 2016) for agricultural students were compared. It was reported that students use IT technologies in the process of learning. Majority of students − 94% (2009) and 98% (2016) positively assessed the usefulness of these technologies in the learning process. The Internet was used mainly for communication (respectively in the investigated years 82.5% and 99.1%). Usefulness of the Internet in the process of studying was marked very high - in 2009 it was 51% positive answers and in 2016 − 77%.

The paper presents possibilities of using by ‒ products of the agri-food sector, in the form of sunflower husks, for energy purposes. Physical and chemical properties in the form of heat of combustion, calorific value for three moisture levels and ash content for two temperatures of combustion were determined and the carbon content (C), hydrogen content (H) and nitrogen content (N) were calculated pursuant to the PN-EN 15104 standard. Analysis of the heat of combustion and calorific value proved good energy properties of the investigated biomass. For the moisture level of 9%, 16%, 32% the heat of combustion was respectively 19.44 MJ∙kg^-1, 17.94 MJ∙kg^-1, 15.03 MJ∙kg^-1, and the calorific value 18.09 MJ∙kg^-1, 16.28 MJ∙kg^-1, 13.16 MJ∙kg^-1. The average ash content of the investigated biomass for the combustion temperature of 600°C and 815°C was respectively 2.12% and 2.04. In the analyzed biomass the nitrogen content was determined at the level of 1.57%, carbon of 43.87% and hydrogen of 6.29%.

The objective of the research was to evaluate soil compaction with selected indexes and to determine the relation between them including results obtained with Proctor’s method. Measurements of penetration resistance and shear vane, dry density of soil particles (ρ_d) and their moisture were made in layers in the following depths: 25-30, 35-40, 45-50 and 55-60 cm. Moreover, the maximum volumetric density of soil particles, particles size distribution, content of calcium carbonate and humus, density of solid particles, reaction, plastic and liquid limit were determined with Proctor's method (ρ_ds). Also, packing density and natural density were measured. It was found out that the investigated soils may be generally included to excessively compacted and susceptible to compaction to an average and small degree. It was shown that soil may be recognized as excessively compacted when the quotient ρ_d/ρ_ds exceeds the value of 0.87.

The continuous technological development requires the use of modern materials also in agricultural engineering. Knowledge of the characteristics of tribological materials pairs cooperating with each other is useful for developing sliding nodes of agricultural machinery. Tribological properties of materials should be assessed for selection of technological materials beyond the economic criterion. The article presents analysis of the characteristics of tribological ball-on-disc wear of polymeric materials used as sliding elements for farm machines. Tribological tests were carried out under dry friction for a polymer-metal pair, and a wear rate and friction coefficient of the sample; the signs of wear were submitted to SEM observations.