Developing learners’ speaking skills in the language classroom is one of the most demanding tasks that foreign language teachers are confronted with. The difficulty results mainly from the fact that the target language functions here as both the medium and the goal of teaching. Research shows that active involvement in communication in the learning process helps in improving language skills. The article discusses the role of classroom communication in learning both the first and the foreign language in the light of selected literature and offers a number of teaching guidelines for effective classroom practice.

Energy storage technology (EST) is an effectiveway to improve the power quality of renewable energy generation (such as solar energy and wind energy), but a single energy storage system (ESS) is difficult to meet the demand for the safe operation of the grid. According to the structure and operation characteristics of the existing battery/super-capacitor hybrid energy storage system (HESS), a battery/super-capacitor HESS is proposed. The working principle and three working modes (the super-capacitor pre-charging cold stand-by mode, the boost mode and buck mode) of the HESS are analyzed in detail. The state equations of the boost mode and buck mode are derived. The state space average method is used to establish the small signal equivalent model under the buck/boost mode. More-over, the charge and discharge control strategy of the HESS is obtained by combining the voltage closed-loop control. The simulation model is built in Matlab/Simulink to verify the effectiveness of the proposed HESS and its control strategy. The results show that the HESS and its control strategy can ensure the DC bus voltage has good stability and superior anti-interference, and it can simultaneously provide large current, increase the battery life, and improve the technical economy of energy storage.

This paper presents the results of tests of selected physical and mechanical properties as well as the chemical composition of two types of natural aggregates: porphyry and diabase, as well as artificial aggregate based on steel slags. Based on the conducted tests, it was established that the physical and mechanical properties of the artificial aggregate exhibit slightly lower parameters as compared to the results obtained for porphyry and diabase aggregates. However, this does not limit the possibility of using the aggregate based on steel slags, as according to the applicable WT-4 and WT-5 standards, it can be used in mixtures unbound to the improved subsoil and layers of the road foundation as well as road mixtures with hydraulic binders for each category of traffic load. The chemical composition of the aggregate based on steel slags differs from the chemical composition of the tested natural aggregates. The slags contain lower amounts of SiO2 and Al2O3, while the concentration of CaO and Fe2O3 is greater. Additionally, heavy metals have also been exhibited in the slags. However, it was established that the alkaline nature of the slags, which is affected by low sulphur content and a significant proportion of CaO, as well as the way the metals occur limit the possibility of heavy metals release and migration from slags. The tested steel slags may constitute a prospective material used in road construction.

The Blue Dyke and Jardine Peak are subvertical hypabyssal intrusions cutting a stratiform volcanic sequence in the Admiralty Bay area on King George Island (South Shetlands, Antarctica ). The rocks are porphyritic, crystal-rich basaltic andesites. Tiny zircon crystals were used for single grain SHRIMP U-Pb dating. The mean ages calculated for the zircon populations from both intrusions indicates Late Oligocene (Chattian) formations. Zircon grains from the Blue Dyke gave the mean age of 27.9±0.3 Ma, whereas those from the Jardine Peak are slightly younger displaying the mean age of 25.4 ± 0.4 Ma: a Late Oligocene (Chattian) crystallization age the inferred of both these intrusions. These are much younger than previous Eocene K-Ar and Ar-Ar ages for such rocks and suggest that formation of the King George Island intrusions can be related to tectonic processes that accompanied the opening of the Drake Passage.

Observations of the surface of the Petuniabukta tidal flat showed the occurrence of dead forms indicating a relative lowering of the sea level. Under the silt deposits of the tidal flat a gravel-clay series was found to occur. Connecting this series with the glacial till covering the lowest marine terrace and with the erosion pavement in the lowest part of the outwaśh plain gave rise to the hypothesis that there might be a record of glacier oscillation. By dating a sample taken from the gravel series substrate, the age of the oscillation was estimated at less than 6370+/- 120 years BP.

In this paper, the PLC-based (Programmable Logic Controller) industrial implementation in the form of the general-purpose function block for ADRC (Active Disturbance Rejection Controller) is presented. The details of practical aspects are discussed because their reliable implementation is not trivial for higher order ADRC. Additional important novelties discussed in the paper are the impact of the derivative backoff and the method that significantly simplifies tuning of higher order ADRC by avoiding the usual trial and error procedure. The results of the practical validation of the suggested concepts complete the paper and show the potential industrial applicability of ADRC.

Active acoustics offers potential benefits in music halls having acoustical short-comings and is a relatively inexpensive alternative to physical modifications of the enclosures. One critical benefit of active architecture is the controlled variability of acoustics. Although many improvements have been made over the last 60 years in the quality and usability of active acoustics, some problems still persist and the acceptance of this technology is advancing cautiously. McGill's Virtual Acoustic Technology (VAT) offers new solutions in the key areas of performance by focusing on the electroacoustic coupling between the existing room acoustics and the simulation acoustics. All control parameters of the active acoustics are implemented in the Space Builder engine by employing multichannel parallel mixing, routing, and processing. The virtual acoustic response is created using low-latency convolution and a three-way temporal segmentation of the measured impulse responses. This method facilitates a sooner release of the virtual room response and its radiation into the surrounding space. Field tests are currently underway at McGill University involving performing musicians and the audience in order to fully assess and quantify the benefits of this new approach in active acoustics.

The subject of the performed experiments comprised standard XR 110 02, XR 110 04 nozzles, TT 110 02, TT 110 04 nozzles and AI 110 02, AI 110 04 air induction nozzles. The working speed of spraying was v_p = 7 km/h. Each nozzle was tested at the following three levels of working pressures: p₁ = 0.2 MPa, p₂ = 0.4 MPa ad p₃ = 0.6 MPa. The spray liquid was pure water at the temperature of 20°C. The plant coverage was determined: s_k – spray coverage, n_k – number of droplets per 1 cm². The analysis of results of maize spraying showed that both standard nozzles and both TT nozzles achieved better results with number of droplets and degree of surface coverage for each of applied operating pressure. The lowest results from all examined kind of nozzles for number of droplets achieved injector nozzles (AI). For operating pressure 0.4 MPa nozzles fulfilled agrotechnical requirements for using insecticids, herbicides and fungicides.

Energy based approach was used in the study to formulate a set of functions approximating the magnetic flux linkages versus independent currents. The simplest power series that approximates field co-energy and linked fluxes for a two winding core of an induction machine are described by a set of common unknown coefficients. The authors tested three algorithms for the coefficient estimation using Weighted Least-Squared Method for two different positions of the coils. The comparison of the approximation accuracy was accomplished in the specified area of the currents. All proposed algorithms of the coefficient estimation have been found to be effective. The algorithm based solely on the magnetic field co-energy values is significantly simpler than the method based on the magnetic flux linkages estimation concept. The algorithm based on the field co-energy and linked fluxes seems to be the most suitable for determining simultaneously the coefficients of power series approximating linked fluxes and field co-energy.

The present work deals with ultrasound assisted crystallisation of lactose from lactose solution. The crystallisation of lactose was completed rapidly by applying the ultrasound waves in the presence of an anti-solvent (n-propanol), at the room temperature (30±3°C). The yield of lactose was found to be more than 85% (w/w) in 4 minutes of sonication. The spread of the crystal size distribution was found to decrease with increase in sonication time.

The key feature of thermosensitive polymers is the reversible transition between the hydrophilic and hydrophopic forms depending on the temperature. Although the main research efforts are focused on their application in different kinds of drug delivery systems, this phenomenon also allows one to precisely control the stability of solid-liquid dispersions. In this paper research on the application of poly(N-isopropylacrylamide) copolymers in processing of minerals is presented. In the experiments tailings from flotation plant of one of the coal mines of Jastrzębska Spółka Węglowa S.A. (Poland) were used. A laser particle sizer Fritsch Analysette 22 was used in order to determine the Particle Size Distribution (PSD). It was proved that there are some substantial issues associated with the application of thermosensitive polymers in industrial practice which may exclude them from the common application. High salinity of suspension altered the value of Lower Critical Solution Temperature (LCST). Moreover, the co-polymers used in research proved to be efficient flocculating agents without any temperature rise. Finally, the dosage needed to achieve steric stabilization of suspension was greatly beyond economic justification.