Passive noise reduction means are commonly used to reduce noise in the industry but, unfortunately, their effectiveness is poor in the low frequency range. By applying active structural acoustic control to the enclosure walls significant improvement of the insulating properties in this frequency range can be achieved. In this paper a model of double panel structure with ASAC is presented. The structure consists of two aluminium plates separated by an air gap. Two inertial magnetoelectric actuators and two piezoceramic MFC sensors were used for controlling the structure. A multichannel FxLMS algorithm with virtual error microphone technique is used as a control algorithm. The signal of a virtual error microphone is extrapolated basing on signals from MFC sensors. Performance of this actively controlled structure for tonal signals at selected frequencies is presented in the article. During the study, a double panel structure was mounted on one wall of sound insulating enclosure located in an acoustic chamber. During the measurements local and global reduction of noise test signal was investigated.

The purpose of the studies was to estimate efficiency of delivering nebulised drugs into the lower respiratory tract through endotracheal tubes (ET tubes) which are commonly used in the treatment of uncooperative patients. Water solution of Disodium Cromoglycate (DSCG) was nebulised with a constant air flow (25 l/min). Experimental studies were done for eight ET tubes with varying sizes (internal diameter, length) and made of two different materials. Size distribution of aerosol leaving ET tubes was determined with the use of aerosol spectrometer. Fine Particle Fraction (FPF) and Mass Median Aerodynamic Diameter (MMAD) were calculated for the aerosol leaving each tube. Additionally, mass of the Disodium Cromoglycate deposited into each endotracheal tube was determined. ET tubes can significantly influence the parameters of delivered aerosol depending on their diameter. FPF of aerosol delivered in to the respiratory tract is lower if small endotracheal tubes are used. However, MMAD and FPF for large endotracheal tubes are almost identical with MMAD and FPF from nebuliser. The results indicate that a substantial fraction of large droplets is eliminated from the aerosol stream in long endotracheal tubes (270 mm). In this case the mass of drug delivered through ET tubes is reduced but the content of small droplets increases (high value of FPF).

This paper outlines a measurement method of properties of microstructured optical fibers that are useful in sensing applications. Experimental studies of produced photonic-crystal fibers allow for a better understanding of the principles of energy coupling in photonic-crystal fibers. For that purpose, fibers with different filling factors and lattice constants were produced. The measurements demonstrated the influence of the fiber geometry on the coupling level of light between the cores. For a distance between the cores of 15 μm, a very low level (below 2%) of energy coupling was obtained. For a distance of 13 μm, the level of energy transfer to neighboring cores on the order of 2-4% was achieved for a filling factor of 0.29. The elimination of the energycoupling phenomenon between the cores was achieved by duplicating the filling factor of the fiber. The coupling level was as high as 22% in the case of fibers with a distance between the cores of 8.5 μm. Our results can be used for microstructured-fiber sensing applications and for transmission-channel switching in liquid-crystal multi-core photonic fibers.

Processing of metal alloys in semi-solid state is a way of producing many near net-shape parts and nowadays is commercially successful. Particular behaviour of alloys in the partially liquid state, having non-dendritic microstructure, is a base for thixoforming processing. Processing materials in the semi-solid state concerns alloys with relatively wide solidification range. Thermodynamic modelling can be used as a one of a potential tools that allow to identify alloys with proper temperature range. It means that the key feature of alloys suitable for thixoforming is a widely enough melting range, allowing for precise control of material temperature. The data gathered from thermodynamics calculations can also pay off in the industrial thixoforming processes design. The goal of this paper is to identify copper alloys which can be successfully shaped in the semi-solid state. Apart to thermodynamic calculations, the observations on high temperature microscope was carried out. During experiments the solidus, liquidus and also deformation temperatures can be determined. An experimental work allows confirming results obtained within the confines of thermodynamic calculations and firstly to determine the deformation temperatures which are the optimal for shaping processes. The basic achievement of this work is an identification of copper alloy groups possible for shaping in the semi-solid state. At the first part of the paper, the basic criteria of suitable alloys were described. Next, both the solid fraction curves for copper alloys with different alloying elements using ProCAST software and the phase diagrams were determined to identify the solidification temperature ranges of these alloys. In the second part of these paper, the identification of the deformation temperatures was carried out with use of high temperature microscope observation.

Software power protection tester implemented in a real-time operating system (RTOS) might replace the conventional testing setups in IEC 61850 protection systems. This paper describes an open power protection testing platform. Linux RT capabilities related to runtime environment for such a tester are examined and OS latency sources are identified and evaluated. An algorithm for a multithreaded tester operation is proposed, including Sampled Values (SV) publisher, GOOSE input/output and time synchronization. SV and GOOSE services implemented in RT Linux environment are evaluated in accordance with IEC 61850‒5 transfer time requirements. Linux PTP time synchronization service of two similar systems controlling its electrical ports is evaluated in different synchronization scenarios. The developed tester is compared to an equivalent conventional setup during the test of IED over-current function. The conducted tests show that the Linux implementation of power protection tester in the case of scheduler latency, time synchronization accuracy and transfer time all meet the requirements of IEC 61850.