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1
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Effects of B₂O₃ Addition on the Sintering Behavior of 0-5-10% ZrO₂ Doped BaTiO₃ Based Ceramics

100%
Öksüz K., Şen Ş., Şen U.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1086-1089
EN
In this study, the effect of B₂O₃ addition on the sintering behavior of 0-5-10% ZrO₂ doped barium titanate based microwave dielectric ceramics were investigated. For this purpose, the powder mixtures consisting of BaCO₃, TiO₂ and ZrO₂ were prepared by ball milling technique in alcohol using ZrO₂ balls at 200 cycle/min for 20 h. The prepared powders were calcined at 900°C for 2 h. Produced powders were mixed 0.5% B₂O₃ and 5% PVA and pressed as green body under the pressure of 100 MPa. The disc-shaped die-pressed samples were sintered at 1250°C, 1350°C and 1450°C for 4 h. X-ray diffraction analysis showed that the main phases formed in the sintered samples are BaTiO₃ and Ba(Ti_{1-x}Zr_{x})O₃. The scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to investigate microstructure of the sintered samples. The bulk densities of the sintered samples increased with the addition of B₂O₃ content due to the low number of pores trapped between the grains.
2
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Study of the Mechanochemical Reduction of Ilmenite Concentrate by Addition of Aluminum

80%
Achimovičová M., Gock E., Turianicová E., Kostova N., Velinov N., Kaňuchová M., Baláž P.
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vol. 126
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issue 4
867-870
EN
Mechanochemical reduction of ilmenite concentrate (FeTiO_{3}) with elemental aluminum powder was performed by high-energy milling in an industrial eccentric vibratory ball mill ESM 656-0.5 ks (Siebtechnik, Germany). The mechanochemically reduced ilmenite with various times of milling was characterized by X-ray diffraction analysis, which confirmed the presence of the Al_2O_3 and Fe_2Ti phases after 120 min of milling. Thermal analysis evidenced the completion of a mechanochemical reduction during milling. After 360 min of milling, the Fe_2Ti phase decomposed to α-(Fe,Ti) alloy, which was proven by ^{57}Fe Mössbauer spectroscopy. X-ray photoelectron spectroscopy detected the amorphous TiO phase in product after mechanochemical reduction, which is in accordance with thermodynamic prediction. Decreasing of specific surface area after 60 min of milling resulted from growing layers of the solid products of FeTiO_3 mechanochemical reduction.
3
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Modelling and Simulation of 3 Blade Helicopter's Rotor Model

61%
Latalski J., Bocheński M., Warmiński J., Jarzyna W., Augustyniak M.
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vol. 125
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issue 6
1380-1384
EN
Results of model tests of a rotating composite beam with integrated piezoelectric active element are presented in the paper. A proposed electromechanical system is a simplified model of the structure of a modern helicopter rotor blade. Numerical analysis of the considered system is developed by means of the finite element method. In addition, the laboratory setup has been built in order to perform real experimental studies. Selected static and dynamic characteristics of the object are determined by a series of numerical simulations. The results are compared with the outcomes of tests performed on the experimental setup. A very good agreement between numerical simulation and experiment results is observed.
4
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Efficiency Measurements of Ultrasonic Generator for Welding

61%
Kardyś W., Milewski A.
Acta Physica Polonica A
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2015
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vol. 128
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issue 3
456-460
EN
The paper presents results of theoretical analysis as well as practical measurements of efficiency in ultrasonic welding system with main focus on ultrasonic generator. Through analysis and tests were performed using 3 kW 20 kHz Sonic Blaster ultrasonic generator manufactured by ITR. Special equipment was used to perform accurate measurements of input and output power of such generator since an output signal of the ultrasonic generator has high voltage amplitude up to 3 kV and frequency of 20 kHz. Artificial load able to dissipate up to 6 kW of continuous power was designed to simulate ultrasonic transducer. Power measurements were performed on the mains supply of the generator using accurate true RMS power meter and load side measurements were performed using specially built power metering system able to measure high voltage 20 kHz signals based on calibrated high voltage resistive divider and high frequency current transducer.
5
Content available remote

Universal Ultrasonic Generator for Welding

61%
Kardyś W., Milewski A., Kogut P., Kluk P.
Acta Physica Polonica A
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2013
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vol. 124
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issue 3
456-458
EN
The paper presents design and parameters of a multifunction ultrasonic generator manufactured by Tele and Radio Research Institute. Efficient usage of ultrasonic welding and cutting technology depends on the ability to precisely control process parameters and tune those parameters to suit particular needs. Ultrasonic generator is responsible for such control and tuning. Presented design incorporates powerful 32 bit Cortex M4 microcontroller with floating point unit which allows using modern signal processing methods to calculate parameters of ultrasonic stack in real time. Calculated parameters, especially impedance of the stack are used to estimate load level and identify phases of the welding process such as melting of the welded material. Precise control of the output signal is possible due to innovative design of the direct digital signal synthesis unit implemented in programmable logic device (CPLD). Resonant inverter topology of the generator front end ensures high electrical efficiency of the device. Designed generator is equipped with various communication interfaces such as USB host and slave, Ethernet, Bluetooth, CAN and RS485. Multiple digital inputs and outputs together with load cell interface, 4-20 mA receiver and 0-10 V analog input enable the generator to monitor and control entire ultrasonic welding system without the need of a PLC unit.
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