The aim of the study was the assessment of the influence of EM-A preparation on the properties of soil structure of medium and fine texture. Soil material for the incubation experiment was collected from humus arable horizons of four mineral soils: Gleyic Chernozem (soils A, B and D) and Haplic Fluvisol (soil C). The experiment was conducted in containers of 2000 cm3, where soil material of about 3 kg was placed and three doses of EM-A were added. After a 12-month incubation, aggregates of 1 cm3 were cut out. Their basic physical properties (density, porosity) were determined, as well as the parameters which characterize the structure: dynamic and static water resistance, secondary aggregation after dynamic and static water resistance and capillary water capacity. The effect of additions of EM-A was not significant for majority of analyzed soil properties.
The paper presents a sensorless control of permanent magnet synchronous generator (PMSG) in a variable-speed wind energy conversion system. The system of wind turbine consists of PMSG and back-to-back power converter. The back-to-back converter system is composed of machine side converter (MSC) and grid side converter (GSC). In the control of MSC and GSC the methods of vector control have been applied. For operation of MSC the method of Rotor Field Oriented Control (RFOC) with MPPT algorithm has been used. For estimation of angular rotor position and angular speed the flux linkage estimator with synchronous frame phase locked loop (SF-PLL) has been used. In the control of GSC the method of Voltage Oriented Control (VOC) has been considered. Simulation studies have been carried out in order to evaluate the system of sensorless strategy. The results of simulation studies demonstrate the high efficiency and high accuracy of the sensorless control system considered.
The article presents control strategy for the operation of a variable-speed wind energy conversion system with permanent magnet synchronous generator (PMSG). The electrical system of wind turbine consists of PMSG, Switch Mode Rectifier (SMR) and Grid Side Converter (GSC). The SMR converter is composed of an uncontrolled diode bridge and a DC/DC boost converter. In the control of the DC/DC boost converter the algorithm of Maximum Power Point Tracking (MPPT) has been applied. The MPPT algorithm allows the wind turbine to operate at maximum value of power coefficient in a wide range of wind speed. In the control of Grid Side Converter a method of Voltage Oriented Control (VOC) has been applied. High efficiency and accuracy of this control system were confirmed by simulation studies.
This work presents the results of a four-year study on the determination of the range of soil groundwater drainage caused by the operation of the Tomisławice lignite open-cast mine. The performed analyses covered the area of 9600 ha which included 24 villages. It was found that operation of Tomisławice open-cast mine caused noticeable changes of soil groundwater level in the areas adjacent to the excavation. It consequently resulted in considerable changes in soil water regimes types on grassland areas but it did not always lead to soil degradation processes. However, the deterioration of soils hydrological conditions may cause disappearance of certain hydrophilous grass species.
The paper presents physical and water properties of six soils located in the areas directly adjacent to “Drzewce” lignite open cast mine (KWB Konin). The conducted works included preparation of pits of various soil types in points characteristic to large and representative soil allotments. The selected soil types represented mineral and organic soils. Samples of disturbed and undisturbed structure were taken from various genetic horizons for laboratory analysis. Such properties as content of total carbon, texture, specific density, bulk density, total and drainage porosity, moisture, saturated hydraulic conductivity, the potential of water bonding, total and readily available water, and total retention were determined in the samples from the horizons of 0–100 cm. The investigated soils showed mostly sandy texture with few local loam insertions. Texture and the content of organic matter were the most important parameters which influenced all analyzed properties. Morphology and the properties of the examined soils as well as deep level of soil – ground water were decisive factors when categorizing them as a precipitation-water type. Such soils will not undergo degradation caused by the dehydrating depression cone of open cast mine.
Understanding the effect of long-term drainage of peatland areas is helpful in future peatland management and regulations of water conditions. The aim of this work was to assess the current state of fen peatland soils in the Grójecka Valley (eastern part of the Wielkopolskie voivodeship, central Poland), affected by long-term agricultural use (pastures, meadows) since the 1960s and potentially by lignite open pit mining industry (KWB Konin) since 1980s. Field studies were carried out in 2015 in selected fen peatland areas. Soil material for laboratory analysis was collected from genetic horizons from four soil profiles. The surface horizons of studied organic and organo-mineral soils were built with well-developed moorsh material. They were classified as medium moorshiefied – MtII (profile 1, 3 and 4) and strongly moorshiefied – MtIII (profile 2). Obtained results of physical and physico-chemical analysis indicate that long-term peatland utilization connected with potential impact of the lignite mining, transformed mainly the upper horizons of studied organic and organo-mineral soils. However, despite obvious strong human impact on peatlands ecosystems, we cannot exclude the climate variables, what should be confirmed by long-term monitoring program. Furthermore, presented paper indicated that new subtype moorsh-muddy soils (in Polish: gleby murszowo-mułowe) within the type of gleyic soils should be implemented in the next version of Polish Soil Classification.
The paper presents the characteristics of selected physical, chemical, and water properties of four mineral arable soils characterized with heavy and very heavy texture. Soil samples from genetic horizons of black earths from areas near Kętrzyn, Gniew and Kujawy, and alluvial soils from Żuławy were used. The following properties were determined in the samples of undisturbed and disturbed structure: texture, particle density, bulk density, porosity, natural and hygroscopic moistures, maximal hygroscopic capacity, saturated hydraulic conductivity, potential of water bonding in soil, total and readily available water, total retention in the horizon of 0–50 cm, drainage porosity, content of organic carbon and total nitrogen Parent rocks of these soils were clays, silts and loams of various origin. High content of clay fraction strongly influenced the values of all the analyzed properties. All the examined soils had high content of organic carbon and total nitrogen and reaction close to neutral or alkaline. High content of mineral and organic colloids and, what follows, beneficial state of top horizons’ structure, determined – apart from heavy texture – low soil bulk density and high porosity. The investigated soils were characterized by high field water capacity and wide scopes of total and readily available water. The saturated hydraulic conductivity was low and characteristic to heavy mineral arable soils. The parameter which influenced the variability of analyzed parameters most was texture.
Research into the influence of ethoxylated alcohols on the citric acid transport through polymer inclusion membranes (PIMs) has been carried out. This process may be used in the future as one of the methods of citric acid isolation. Ethoxylated alcohols, which were GENAPOL® X020, X060 and X150, served as both: plasticizer and carrier. The results showed that the maximum values of citric acid fl ux [mol/(m2.s)] were equal to: 1.02.10-4 (X020), 1.57.10-4 (X060) and 1.77.10-4 (X150). The obtained results allow proceeding further study on using the polymer inclusion membranes, as an alternative to traditional methods of citric acid separation, which are precipitation and extraction.