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1
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Sonolysis and Sonoacidification οf Ultrasonic Disintegration οf Excess Sludge

100%
Zielewicz E.
Acta Physica Polonica A
|
2008
|
vol. 114
|
issue 6A
A-259-A-264
EN
The expected effect of ultrasonic disintegration of excess sludge is particle dispergation and cell lysis i.e. the elimination of sludge microorganisms and the release of the contents of dead cells into the sludge liquid which results in an increase in chemical oxygen demand. Sonolysis also formed the basis for the intensification of volatile fatty acids production during the acid fermentation of excess sludge treated ultrasonically. In this study the investigations into the direct effects of excess sludge ultrasonic treatment revealed an increase in volatile fatty acid concentration directly (without fermentation process) after the ultrasonic treatment which is closely related to sonolysis.
2
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Piezoceramic Transducers Selection Method for High Power Ultrasonic Devices

38%
Kluk P., Milewski A.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 3
719-722
EN
A universal method for selecting piezoceramic transducers used in high power ultrasonic devices such as ultrasonic welding and cutting systems has been presented. The key element of such systems is a high power ultrasonic sandwich transducer consisting of a stack of piezoceramic transducers mounted between two masses. Because of relatively large dispersion of piezoceramic transducer parameters between production lots, they must be selected in order to obtain a high quality and long-life sandwich transducer. Presented selection method consists of three stages. First, the parametric identification of the Butterworth-Van Dyke equivalent circuit model is performed based on piezoceramic transducer electrical impedance measurements. Next, the electrical impedance frequency samples are estimated using the identified Butterworth-Van Dyke model. Finally, the k-means clustering algorithm is used to select the best fitted piezoceramic transducer sets.
3
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Efficiency Measurements of Ultrasonic Generator for Welding

38%
Kardyś W., Milewski A.
Acta Physica Polonica A
|
2015
|
vol. 128
|
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.
4
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Universal Ultrasonic Generator for Welding

38%
Kardyś W., Milewski A., Kogut P., Kluk P.
Acta Physica Polonica A
|
2013
|
vol. 124
|
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.
5
Content available remote

Measurement System for Parameter Estimation and Diagnostic of Ultrasonic Transducers

32%
Kluk P., Milewski A., Kardyś W., Kogut P., Michalski P.
Acta Physica Polonica A
|
2013
|
vol. 124
|
issue 3
468-470
EN
The paper presents an architecture and design of measurement system and methods for parameter estimation and diagnostic of ultrasonic transducers used in ultrasonic welding and cutting systems manufactured by Tele and Radio Research Institute. The key element of the ultrasonic welding and cutting system is a high power ultrasonic transducer implemented as a sandwich transducer consisting of a stack of piezoelectric ceramic rings mounted between two masses. High quality welding and cutting demand predetermined frequency characteristic of transducer impedance. Also important are: high energy efficiency, high coupling coefficient, low dielectric loss, and the optimal radiation pattern. In order to manufacture high quality and long-life transducers the piezoelectric rings must be selected and the sandwich transducers diagnosed on the basis of their measured parameters. Presented measurement system takes advantage of the virtual instrument technique in the NI LabVIEW environment. It uses Agilent U2761A Function Generator, U2531A Data Acquisition Unit, and the linear amplifier to measure impedance frequency characteristic in the frequency range of 10 kHz to 100 kHz. Moreover, the system can measure the vibration amplitude in the range of 1 μm up to 100 μm, using an optical sensor, and the temperature of the transducer using a pyrometer sensor.
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