2019, Vol. 17, No. 2

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/5393

Sirvi

Nüüd näidatakse 1 - 20 30

Properties of soil and peat humic substances from Latvia
(2019) Klavins, M.; Purmalis, O.; Grandovska, S.; Klavina, L.
The acidity, elemental, functional and spectral (UV, fluorescence, IR spectra) characteristics of humic substances isolated from soils of different origin and peat in Latvia are described and compared with values common for humic substances of different origin, to evaluate the character of processes during humification. Substantial dependence of properties of humic substances on the humification conditions are found.
The course of drying and colour changes of alfalfa under different drying conditions
(2019) Kic, P.
One of the conditions for successful livestock breeding and efficient livestock production is to ensure quality feed. High quality feed for livestock is alfalfa, which has a very high nutritional value and its cultivation is also important for crop production in terms of improving the soil structure and nitrogen enrichment. The aim of this paper is to inform about the experimental investigations of alfalfa drying and colour changes under different drying conditions. The results of natural convection at 27.5 °C and 40% relative air humidity are compared with forced convection at 1.2 m s -1 air flow velocity at the same air temperature and with results of drying by natural convection at 50 °C. The dry matter content was measured gravimetrically after drying in a hot air dryer at 105 °C. Higher drying rates shorten the time required for drying and earlier preservation and storage in the hayloft or in the hay bales. This reduces the risk of wetting of feed such by rain and degradation by fungi, etc. A shorter drying time is also important in terms of energy savings. The precise knowledge of the drying process and drying curves allows also to determine the appropriate time for storage and conservation for production of another type of fodder e.g. haylage or silage. The measurement results show a positive effect of higher drying speeds as well as increased air temperature. Higher drying air temperature during convection led to the partial lightening and greater yellowing of the feed.
The environmental noise level in the rejuvenation pruning on centuries-old olive tree
(2019) Abenavoli, L.M.; Zimbalatti, G.; De Rossi, A.; Papandrea, S.; Proto, A.R.
In the Italian agricultural economy, olive cultivation plays a fundamental role, and this is especially true for the southern regions where almost all cultivation is spread. In Calabria, in particular, olive cultivation has seen over the last few decades significantly improve the quality of production also as a result of investments aimed at the creation of new mechanizable plants and/or the modernization of existing ones; today some areas have got both PDO and PGI certification. In the ‘Piana di Gioia Tauro’, located north-west of the Reggio Calabria metropolitan area, olive growing extends over 20,000 hectares and the presence of centuries-old olive tree is still widespread. The olive varieties mainly belong to the local cultivars of ‘Sinopolese’ and ‘Ottobratica’, characterized by a remarkable rusticity and high development, perhaps unique in the world; they reach 20–25 meters high, forming what is called a ‘forest of olive trees’. The pruning operations are carried out by means of chainsaws of different power and size whereby, in addition to the previously described difficulties, operators are exposed to prolonged periods of noise levels. The purpose of this study is precisely to assess the exposure of operators to this particular olive grove. The aim is to identify the acoustic levels generated by the two pruning and cross-cutting activities, the risk thresholds and the exposure to which the individual workers of the two work sites are subjected, giving indications on the appropriate safety distances to maintain (according to current regulations) compared to noise sources.
Spatial distribution of thermal variables, acoustics and lighting in compost dairy barn with climate control system
(2019) Damasceno, F.A.; Oliveira, C.E.A.; Ferraz, G.A.S.; Nascimento, J.A.C.; Barbari, M.; Ferraz, P.F.P.
The main objective of this research was to evaluate the spatial distribution of the thermal variables, acoustics and lighting in climate controlled compost dairy barn. The experiment was conducted in October 2017, in a farm located in the west of Minas Gerais state, Brazil. For the study, the interior of the animal facility was divided into 120 meshes equidistant points, in which air temperature (tdb), relative humidity (RH), noise, illuminance, and air speed (Vair) were manually collected. The technique of geostatistics was used to evaluate the distribution and spatial dependence of variables. Spatial distribution maps showed the occurrence of high variability of attributes and content within the animal facility. Thermal environment variables showed alert situations throughout practically the entire facility. The noise and luminance levels were within the recommended values.
Spatial variability of litter temperature, relative air humidity and skin temperature of chicks in a commercial broiler house
(2019) Ferraz, P.F.P.; Ferraz, G.A.S.; Schiassi, L.; Nogueira, V.H.B.; Barbari, M.; Damasceno, F.A.
The thermal environment inside a broiler house has a great influence on animal welfare and productivity during the production phase. Among the importance of the chicken litter is the function of absorbing moisture, provide thermal insulation and provide a soft surface for broilers. The skin temperature is an important physiological parameter to quantify the thermal comfort of animals, its variations may occur as a function of thermal variables. So, the aim of this work was to analyse the magnitude and spatial variability of chicken litter temperature and relative humidity of the air and to correlate them with the spatial distribution of chicks’ skin surface temperature throughout the broiler house during the 7th, 14th and 21st days of the chicks’ life, using geostatistical techniques. The experiment was performed in a commercial broiler house located in the western mesoregion of Minas Gerais, Brazil, where 28,000 male Cobb chicks were housed. The heating system consisted of an industrial indirect-fired biomass furnace. The heated air was inflated by an AC motor, 2,206 W of power, 1,725 RPM. Geostatistical techniques were used through semivariogram analysis and isochore maps were generated through data interpolation by kriging. The semivariogram was fitted by the restricted maximum likelihood method. The used mathematical model was the spherical one. After fitting the semivariograms, the data were interpolated by ordinary kriging. The semivariograms along with the isochore maps allowed identifying the non-uniformity of spatial distribution of the broiler litter temperature throughout the broiler house for 3 days of chicks’ life. It was observed that skin surface presented a positive correlation with the litter temperature and a negative correlation with the air humidity. The semivariograms along with the isochore maps allowed identifying the non-uniformity of spatial distribution of the litter temperature, air humidity and skin temperature of chicks throughout the broiler aviary for the three days. In addition, the use of geostatistics and distribution maps made possible to identify different environmental conditions in regions inside the broiler house that may harm the development of chicks.
Thermal comfort of pigs housed in different installations
(2019) Cecchin, D.; Ferraz, P.F.P.; Campos, A.T.; Sousa, F.A.; Amaral, P.I.S.; Castro, J.O.; Conti, L.; Cruz, V.M.F.
In an intensive production system, the environment directly influences the comfort and welfare of pigs. Animals under heat stress may exhibit behavioural changes and changes in physiological parameters, such as increased body temperature, respiratory and cardiac movements. The aim of this study was to evaluate the thermal comfort of growing and finishing pigs housed in facilities with different construction typologies. The evaluated pens were: pen with water depth (WDP) and pen with partially slatted floor (SLF). Data on the ambient thermal environment in the pens and in the outside were collected automatically using Hobo dataloggers, model U12-013. This equipment recorded the air temperature, relative humidity of the air and black globe temperature in intervals of five minutes. Subsequently the variables were used in the calculation of the temperature index of the globe and humidity. The physiological responses of the animals were collected: Surface Temperature (ST) and Respiratory Rate (RF). When analyzing the parameters: ST and RF, it was observed that the WDP pen presented a significant difference in all the observed hours, with an increase observed throughout the day, and the SLF pen presented a difference at 9:00 a.m. presenting a lower value than the other schedules evaluated. The BGHI inside the pens showed average values in the hottest period of the day slightly above what is recommended for adult pigs. Both facilities during the hottest time of the day demonstrated a similar trend in relation to the evaluated variables, so it was concluded that both pens provided the same conditions of thermal comfort for the animals.
Assessment of applied microwave power of intermittent microwave-dried carrot powders from Colour and NIRS
(2019) Keskin, M.; Soysal, Y.; Sekerli, Y.E.; Arslan, A.; Celiktas, N.
Applied microwave (MW) power level is an essential factor on the quality of the dried agricultural products. Even if higher MW powers result in shorter drying times, they lead to quality degradations. It is almost impossible to know the applied MW power of a dried and powdered product by human vision. Thus, the aim of this study was to predict the applied MW power of carrot powders by using two different instruments, a chromameter and FT-NIRS. The experiments were carried out at nine different power levels (100–500 W) with three replications (N = 27). The colour and NIR reflectance was measured using a chromameter and NIRS system. The data was analysed using PLS regression. The drying time of intermittent MW drying at the highest applied power of 500 W was 1.12–5.47 times shorter than those of other lower applied powers. Applied MW power was a crucial factor on all colour parameters of the powdered carrots. Brightness (L*) decreased significantly with the increase of applied MW power resulting in darker product colours. Data analysis results showed that the NIRS system (R2 = 0.99; SEP = 16.1 W) can predict the microwave power of powdered carrots with significantly better performance than a chromameter (R2 = 0.95; SEP = 29.9 W). But, the chromamater is far more inexpensive when compared with the NIRS system and hence, it can also be used to predict the applied MW power from the colour data relatively well. Also, a mathematical model was developed to predict applied MW power from the colour parameters.
Variety, seeding rate and disease control affect faba bean yield components
(2019) Plūduma-Pauniņa, I.; Gaile, Z.; Bankina, B.; Balodis, R.
Faba beans (Vicia faba L.) have been grown since 8000 years B.C. in the Middle East. Despite their long growing history in the world, there are only few researches carried out in Baltic region in last decades about variety, seeding rate and disease control effect on faba beans’ growth, development and yield formation. Research was carried out at the Latvia University of Life Sciences and Technologies during 2015–2017. Three factors were researched: A – variety (‘Laura’, ‘Boxer’, ‘Isabell’), B – seeding rate (30, 40 and 50 germinate able seeds m-2 ), C – treatment with fungicide (with and without application of fungicide Signum (1 kg ha-1 )). Meteorological conditions were diverse and sometimes caused stress for crop, but in general they favoured faba beans’ growth and development. High average yield of the field beans was obtained during all three trial years, however, yield differed significantly among them. Sowing time was constantly quite early, germination took longer time as expected due to the low air temperature, but later, temperature and humidity level improved and conditions were suitable for plant growth and development with some exceptions during flowering and pod filling. Number of productive stems per 1 m2 was significantly affected only by seeding rate. Plant height in trial site was affected by variety (p < 0.001), fungicide application (p = 0.008) and meteorological conditions (p < 0.001) of the year. Number of pods per plant differed depending on trial year (p < 0.001). Number of seeds per plant had a close positive correlation with number of pods per plant. Whereas number of seeds per pod was a relatively stable and typical characteristic for variety. We can observe correlation between faba bean yield and number of productive stems per 1 m2 at harvest, plant height, number of pods and seeds per plant.
Estonian dairy farms’ technical efficiency and factors predicting it
(2019) Luik-Lindsaar, Helis; Põldaru, Reet; Roots, Jüri; Estonian University of Life Sciences. Institute of Economics and Social Sciences
Milk production is a complex process whose efficiency depends directly on the inputoutput ratio and indirectly on the decisions made at farm and animal level. Decisions made about farm hygiene, dairy cows’ milk yield, cows’ age at first calving etc. affect farms’ efficiency. The aim of this study is to provide an understanding of the factors that affect dairy farms’ technical efficiency. A two-stage approach was used in this study, consisting of a data envelopment analysis (DEA) in the first stage, and classification and regression tree (CART) in the second stage. DEA determined technical efficiency scores (TE), and CART enabled to detect the main factors that influenced efficiency in dairy farms. The analysis studied at the Estonian national level FADN dataset and Estonian Livestock Performance Recording data. 147 Estonian dairy farms were included in this analysis, all of which are specialized in dairy production. DEA results demonstrated that more than half of the farms (55%) were operating efficiently or rather efficiently (TE ≥ 0.900). CART results revealed that the main variables determining efficiency are milk yield per cow's lifetime (kg day-1 ), feed costs (€ kg milk-1 ), and somatic cell count (SCC; 103 ml-1 ). Milk yield per cow's lifetime is a complicated factor as it is influenced by a lot of components (e.g. milk yield, number of lactations, age at first calving, and calving interval), but if it is known at farm level, it is also a useful variable for predicting efficiency. Feed costs per milk kg is an economic variable, i.e. lower costs are related with higher efficiency. Better hygiene (lower SCC) is also related with higher efficiency. The analysis showed that integrating farm accounts data, herd-level genetic information, and milk quality attributes enables to use more specific factors to explain the variation of TE between dairy farms.
Model for ammonia emissions’ assessment and comparison of various dairy cattle farming systems and technologies
(2019) Aboltins, A.; Melece, L.; Priekulis, J.
A dairy cattle farming is an important source of ammonia emissions, particularly in Latvia. Models using a wide range in level of detail have been developed to represent or predict these emissions. Besides, models are useful for improving the understanding of various farm processes and their interacting effects on ammonia emissions. The model for ammonia emissions’ assessing or representing, predicting and comparing for manure management chain of dairy cattle was created. The model provides a tool for evaluating mitigation and management strategies, abatement measures and techniques to reduce of ammonia emissions and improve the sustainability of dairy production systems both on the dairy farm and at the national level. It could be used as a supplement tool for officials and experts. The model estimates those ammonia abatement measures and techniques that have the highest emission reduction potential and opportunities for implementation on Latvia’s dairy farms. The simulation model assesses the ammonia emissions into each stage of the farming: animal housing, manure management - manure handling and storage, and manure application. An important stage in reducing ammonia emissions is manure storage. It should be noted that the main task of the model was to compare the impact of the ammonia emission reduction options. When entering the number of animals, the average nitrogen quantity per animal, the percentage distribution of manure quantities, the first three levels of the program can be used to estimate the amount of nitrogen to be incorporated into the soil and, as the difference; and the amount of ammonia emissions.
Modeling the functional role of the microorganisms in the daily exchanges of carbon and nitrogen in intercropping system under Mediterranean conditions
(2019) Latati, M.; Rebouh, N.Y.; Aouiche, A.; Laouar, M.
Carbon (C) and nitrogen (N) sequestration in plants and soil micro-organisms is considered as a major phenomenon against global warming. The modeling of this phenomenon aims at highlighting the role that the legumes-cereals mixed crop can play in the reduction of greenhouse gases. It is based on field experiments in maize (Zea mays L.)-common bean (Phaseolus vulgaris L.) intercropped system of the cereal agroecosystem in Setif region of Algeria. For this purpose, the MOMOS model was selected and validated in a calcareous soil and low phosphorus (P) conditions. It revealed some mechanisms that control the C and N sequestration in the compartments of the complex soil-plant-atmosphere-microorganism system. CN modeling results show that the daily growth of intercropped maize with common beans is positively correlated with the microbial CN transformation during the cropping cycle, under limited P and N conditions. Thus, this approach revealed the functional role of rhizobial symbiosis in maintaining the balance between the different C and N exchanges from soil to atmosphere and from atmosphere to soil.
Modular sensory hardware and data processing solution for implementation of the precision beekeeping
(2019) Komasilovs, V.; Zacepins, A.; Kviesis, A.; Fiedler, S.; Kirchner, S.
For successful implementation of the Precision Apiculture (Precision Beekeeping) approach, immense amount of bee colony data collection and processing using various hardware and software solutions is needed. This paper presents standalone wireless hardware system for bee colony main parameters monitoring (temperature, weight and sound). Monitoring system is based on Raspberry Pi 3 computer with connected sensors. Power supply is granted by the solar panel for reliable operation in places without constant source for power. For convenient data management cloud based data warehouse (DW) is proposed and developed for ease data storage and analysis. Proposed data warehouse is scalable and extendable and can be used for variety of other ready hardware solutions, using variety of data-in/data-out interfaces. The core of the data warehouse is designed to provide data processing flexibility and versatility, whereas data flow within the core is organized between data vaults in a controllable and reliable way. Our paper presents an approach for linking together hardware for bee colony real-time monitoring with cloud software for data processing and visualisation. Integrating specific algorithms and models to the system will help the beekeepers to remotely identify different states of their colonies, like swarming, brood rearing, death of the colony etc. and inform the beekeepers to make appropriate decisions/actions. This research work is carried out within the SAMS project, which is funded by the European Union within the H2020-ICT-39-2016-2017 call. To find out more visit the project website https://sams-project.eu/.
The effect of Minituber Weight on their Field Performance under a Northern European environment
(2019) Dimante, I.; Mežaka, I.; Gaile, Z.
Weight of potato minitubers as well cultivar affects field performance of minitubers. The aim of this study was to compare minitubers of four weight classes (MtC) (3 to 4.99 g, 5 to 9.99 g, 10 to 19.99 g, and > 20 g) with respect to their field performance. Three year experiments were conducted at AREI, Latvia (57°19′ N, 25°20′ E) between 2014 and 2016. Cultivars ‘Monta’, ‘Prelma’ and ‘Mandaga’ were used. A significant relationship between the number of stems and the number of progeny tubers per plant was detected and the number of stems explained 74% of variation in progeny tuber number. Multiplication rate, expressed as the number of progeny tubers > 25 mm per planted minituber, was in range from 4.2 to 13.1 tubers and was significantly affected by the cultivar and MtC. Cultivar and MtC had significant effect on the number of tubers and tuber yield per m2 . The number of progeny tubers and yield increased with increases for MtC. The highest number of progeny tubers (size > 25 mm) per m2 were obtained from minitubers > 20 g of ‘Prelma’ (93.4), but the highest yield was from minitubers > 20 g of ‘Mandaga’ (4.92 kg m-2 ). The effect of MtC was more pronounced on number of tubers than on tuber yield. Cultivar and MtC determined mean size (diameter (μ)) of progeny tubers. Mean size increased as MtC decreased. MtC had a significant effect on standard deviation (σ) only for ‘Prelma’. When σ was recalculated to coefficient of variation (CV), no significant effect of MtC remained.
Principal components in the study of soil and plant properties in precision coffee farming
(2019) Ferraz, G.A.S.; Ferraz, P.F.P.; Martins, F.B.; Silva, F.M.; Damasceno, F.A.; Barbari, M.
In this work, a principal component analysis was performed to evaluate the possibility of discarding obsolete soil and plant variables in a coffee field to eliminate redundant and difficult-to-measure information in precision coffee farming. This work was conducted at Brejão Farm in Três Pontas, Minas Gerais, Brazil, in a coffee field planted with 22 ha of Topázio cultivar. The evaluated variables were the yield, plant height, crown diameter, fruit maturation index, degree of fruit maturation, leafing, soil pH, available phosphorus (P), remaining phosphorus (Prem), available potassium (K), exchangeable calcium (Ca2+), exchangeable magnesium (Mg2+), exchangeable acidity (Al3+), potential acidity (H + Al), aluminium saturation (N(Al)), potential CEC (CECp), actual CEC (CECa), sum of bases (SB), base saturation (BS) and organic matter (OM). The data were evaluated by a principal component analysis, which generated 20 components. Of these, 7 representing 88.98% of the data variation were chosen. The variables were discarded based on the preservation of the variables with the greatest coefficients in absolute values corresponding to the first component, followed by the variable with the second highest absolute value corresponding to the second principal component. Based on the results, the variables V, OM, fruit maturity index, plant height, yield, leafing and P were selected. The other variables were discarded.
Ranking irrigation schemes based on principle component analysis in the arid regions of Turkey
(2019) Kartal, S.; Değirmenci, H.; Arslan, F.
Water is a scarce resource and thus irrigation schemes in arid regions have become more important. The irrigation sector which uses most of the water resources has to cope with global warming, disasters and water scarcity around the world, particularly in the Mediterranean countries, including Turkey. Irrigation schemes, which were built by DSI (State Hydraulic Works) and whose operation and maintenance management was transferred to water user associations, play a crucial role in irrigated agriculture in Turkey. In order to improve the performance, weakness and strengths of irrigation schemes are determined by performance indicators (system operation, financial and production efficiency) which show the overall information about them. In the present study, seven irrigation schemes located in an arid region of central Anatolia were chosen to assess the irrigation performance using principal component, correlation and cluster analysis while quality index showed the rank of the irrigation schemes. We found that the average total annual volume of irrigation supply was 7648.58 m3 ha−1 and the average relative water supply was 1.91 during the 11 years between 2006 and 2016. In this region, higher inverse correlations were due to using surface irrigation methods (51.3%). As of 2017, the irrigation schemes have weak water distribution systems, on an average, consisting of 55.5% open canals, 22.5% canalette and only 10% pipes. According to the quality index, financial and system operation indicators are more effective than that of production efficiency indicators. In conclusion, average irrigation ratio (55.68%) can be increased by improving the water distribution system, and the technology used on both management and farm levels.
Assessment of production zones modelling accuracy based on satellite imaging and yield measurement of selected agriculture plot
(2019) Jelínek, Z.; Starý, K.; Kumhálová, J.
Currently, remote sensing or yield monitor equipment offer possibilities how to estimate productivity of the agriculture field. That is why the main aim of this study is to assess how the latest satellite images from vegetation season and final yield data from combine harvester can be used to predict yield and to assess site-specific zones productivity. The study is focused on the accuracy of these systems for the field productivity estimation. The 24.7 ha experimental field is located near to Vendoli village (the Czech Republic) and it is cultivated by conventional agricultural practices with emphasis on typical agricultural crops growing in the Czech Republic (winter wheat, spring barley and winter rape). The results showed that both methods of estimation can be used for yield prediction. Nevertheless, each of them need specific processing and has typical limitations.
Properties of biofuel fly ash and capabilities of its use for agricultural needs
(2019) Kulokas, M.; Zaleskas, V.; Pedišius, N.; Praspaliauskas, M.; Buinevičius, K.
The use of various types of biomass for energy production provides great prospects for reducing the consumption of fossil fuels and the negative impact on the environment. However, the use of biomass, in particular agromass for this purpose, results in relatively large amounts of bottom ashes and fly ashes, the composition and properties of which also raise a number of additional environmental problems. The composition and properties of fly ash are investigated in the paper, taking into account the possibilities of utilizing them for soil fertilization and other applications. Fly ash samples were collected from bunkers of flue gas cleaning equipment (electrostatic precipitator and cyclones) installed after water heating boilers, which are firing wood chips and chuffed straw. The composition of fly ash was determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) while particle size distribution was obtained using scattered-light aerosol spectrometer. Electrical Low Pressure Impactor (ELPI) was used to separate fly ash into 14 groups by particle diameter, and the analysis of their composition showed differences in the composition of the fly ash collected in cyclones and Electrostatic Precipitators (ESP). An analysis of the composition of samples in regard to the existing heavy metals norms and considering concentrations of elements beneficial to the growth of plants, enables to prepare recommendations for fertilization. The determined alkalinity of fly ash pH 13 confirms the possibility of their use for reducing soil acidity. The analysis of fly ash composition has shown that they contain elements, important for plant growth (Ca, Mg, K, P, N, S), and their concentrations determine the further use for soil quality improvement because the amount of these elements in the acid soils is reduced.
Comparison of lycopene and β-carotene content in tomatoes determined with chemical and non-destructive methods
(2019) Alsina, I.; Dubova, L.; Duma, M.; Erdberga, I.; Avotiņš, A.; Rakutko, S.
Tomatoes are one of the most popular vegetables due of their wide use as food. Tomatoes are not only tasty fruit, but one of its benefits - high carotenoids content is well-known. Non-destructive analyses methods are used more and more in different industries. It is cheaper, faster and environmentally friendly way of analyse than traditional chemical methods. But these methods need references to the traditional ones. The aim of this study was to find the correlation between lycopene and β-carotene content in tomatoes determined with reflectance spectrometer and extraction of pigments. Content of two carotenoids (lycopene and β-carotene) was determined in 27 varieties of tomatoes. Red, pink, orange, yellow and brown fruits were included in experiment. Reflectance spectrums of tomatoes fruits were obtained with remote sensing portable spectroradiometer RS-3500 (Ltd.Spectral Evolution). Tetrahydrofuran was used for extraction of pigments. Absorption spectra of extract were obtained by spectrophotometer UV-Vis -1800 (Ltd. Shimadzu). Linear regression analyses were performed to correlate spectral data with lycopene and β-carotene concentrations measured by pigment extraction. The best reflectance region for lycopene spectral detection was 570 ± 5 nm, but for β-carotene 487 ± 5 nm. Reflectance indexes for both pigments were worked out. High linear correlation (R2 > 0.9) between spectral parameters and lycopene concentration was detected. Correlation between results obtained with methods used for β-carotene determination was lower and depended of colour of tomatoes fruits.
Measurements of wireless detectors used to monitor animal movements in livestock farms
(2019) Hart, J.; Hartová, V.
At present, there is a great interest in monitoring and automating farm animals and livestock farming. There are many systems and methods to check the movement of animals in certain areas. One option is to use motion detectors. However, some installations are so specific that they require the use of wireless motion detectors. They not only have to fulfill their functional part but also have a sufficiently strong signal that should not interfere outside the defined ISM bands. Due to the frequent deployment of different types of these detectors, research has been carried out to monitor shortcomings in frequently used types of wireless detectors. This research defines which tested detectors are fully usable according to the standards and which need to be modified by the manufacturer. Also, based on measurements, the basic risks and recommendations for the use of individual types of tested detectors are defined.
Discrete element simulation of rapeseed shear test
(2019) Kuře, J.; Hájková, L.; Hromasová, M.; Chotěborský, R.; Linda, M.
SuiTable equipment are required for storage and transportation of rapeseed which are developed according to rules for bulk matters. It is one of reasons where bulk matter properties are important to the design. Bulk matter properties are important to known as angle of repose, internal friction, external friction, adhesivity force and other bulk properties. Experimental values of bulk properties are added to mathematical models. The model should be calibrated with adequate experiment. The shear test is one of popular calibration test for bulk matters so that be able done experiment and numerical model in one. The aim of this paper is simulation of rapeseed bulk properties during shear strain and flow and its evaluation and calibration with experimental tests. RockyDEM software was used for numerical simulation of rapeseed. Shear test, angle of repose, static and dynamic friction test were used to calibration of the numerical rapeseed model. Sensitivity of numerical model is discussed on the bulk properties.

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