Assoc.Prof.Dr. Levent PARALI
Electrical Electronics Engineering
Wer nichts weiß, liebt nichts.
  Wer nichts tun kann, versteht nichts.
     Wer nichts versteht, ist nichts wert.
        Wer meint, alle früchte würden gleichzeitig
           Mit den erdbeeren reif, versteht nichts von den trauben.

Scientific Research


 SPRC: Scientific Research Project Committe 


Project Number        Foundation      Subject                                                                  


   2007-087                 SRPC             Computer Controlled Real Time Temperature Data Acquisition System (Completed)



The reliability of measurement techniques is ensured by taking advantage of accurate measurement methods and in addition to this by minimizing the measurement errors which would occur due to the external effects such as the interaction of product, observer, device or environment.

Among these, the temperature measurements done by thermocouple are really important. 

By the help of the real time meaurement method which is used to measure temperature, the temperatute change in the measuring point can be detected and taken into account in a very short time, to say in nanoseconds, by using computers.This gives us an idea about to what point the technological improvements come.

Related to this topic, an application named Computer Controlled Real Time Temperature Data  Acguisition System is developed by the help of configurable embedded system hardware which is produced by National Instruments and the virtual instrumentation program development platform, named LabView.  

By using “Computer Controlled Real Time Temperature Data Acguisition System” computer based measurement tracking and control display is created. Moreover, by this feature it is provided that all temperature measurements are recorded in the computer environment.



Project Number        Foundation      Subject                                                                  


   2008-064                 SRPC             Computer Controlled Real Time Measurement and Control System (Completed)



The system is a general purpose measurement and control system. Using the system such as temperature, pressure, strain, etc. with many physical quantities and such as current, voltage, etc. with many electrical variables can be measured. 

LabVIEW graphical program is used in order to save measurement data. Among the studies,monitoring of temperature data from a different points, a direct current electric motor speed control, position control of a two-axis pneumatic actuated manipulator arm, Neural Network fault diagnosis for a servopneumatic system and data collection using the photo voltaic panels from the Celal Bayar University Turgutlu Vocational School campus  are been numbered.



Project Number        Foundation      Subject                                                                  


   2012-014                 SRPC             Obtaining High-Resolution Radiation Spectroscopy by Digital Signal Processing

                                                        System (Completed)



Alpha, beta, gamma and X-Rays emitted by natural and artifical radiation sources used in many applications such as industrial, research, education, security and consumer products. Radiation applications in medicine have great importance in medical diagnosis and therapy such as nuclear imaging and tumor termination. The use of X and gamma rays in industry to determine the structural defects of industrial products such as pipes, steam boilers, machine parts, casting is called as radiography. Radiography is used in density, thickness and weights of materials such as iron, steel, rubber, paper, chipboard, sugar, yarn and glass especially in the production period. X-rays are used for imaging the inside of the luggage and cargo in the airports, customs and ports etc. for security. Prospecting of some minerals (iron, cupper and so on), grinding and production of materials related to these, sensitive structure analyses are also performed with the radiation sources. In the sterilization of medical tools and components, extension of the expiration date of foods, protection of dry foods and making better of physical conditions of plastic materials are utilized from the ionizing radiation. 

Precise measurement of radiation will decrease the errors in the anticipated works and lead to exact approaches especially in diagnosis and therapy subjects. 

By means of the proposed Digital Signal Processing (DSP) via this project, high resolution spectroscopy measurement have performed in a computer medium and precise, straight, sensitive and fast determination of the artificial radiation. In the spectroscopy system, an analog signal which has adequate amplitude was obtained by increasing the detector signal using both amplifier and a preamplifier. Obtained analog signal have been digitized by a PCI 5122 digital electronic device and this digitized datum have been analyzed by Labview software storing in a computer, leading to advanced spectral analysis process. The calibrated radiation sources called as 22Na, 137Cs, 60Co where located in the Centre of Advanced Technologies and Materials’ laboratory of  Palacky University from Czech Republic are used in this project.



Project Number        Foundation      Subject                                                                  


   2015-016              SRPC              The Design, Fabrication and Characterization of Piezoelectric Sensors (Completed)



Nowadays, piezoelectric sensors are used in many areas. such as in Robustness check of building structure as Health Structure Monitor, in electricity stroge systems as called Harvesting by converting mechanical energy to electrical energy, in body structure of aircrafts, in the moving parts of the mechatronics systems, in voice stimulator as buzzer, in microphones and headphones, in the underwater wireless ultrasonic communications. Smart materials that has piezoelectric properties, find a diverse range of applications in the technology, industry and other research department. Lead zirconatetitanate (PZT) families are the most used in this area, because of they have high piezoelectric properties such as; piezoelectric coefficient dij, piezosensitivity dij/ƐƐ0, Young modulus (Y), mechanical quality coefficient Qm, electromechanical boundary coefficient Kij and small loss tangents etc. There are many works about PZT and its applications, in addition, some scientist studied composite PZT material using Polyvinylidenefluoride (PVDF) polymer materials and investigated their electromechanical properties. PZT and PVDF composite materials exhibit different electromechanical features when it’s evaluated together as compared to individual.

In this project, firstly an industrial disagne of the hydraulic pres control which has 250 kgF is realized by using a programmable logic controllers (PLC), secondly, it is produced local PZT+PVDF sensors via hydraulic pressure system by controlling with PLC. After that d33 (piezoelectric coefficient), capacitance (C) of these sensors are determined by d33 meter, LCR meter respectively. Furthermore, the frequency-voltage charactrestics of the piezoelectric sensor that integrated on vibration measurement system are defined, It is seen that, fabricated these sensors have generelly 2.5 to 3.7 Vpp (pick to pick) voltage at 10Hz resonance frequency. d33 values of the mentioned sensors are characterized as 10.5-8.6 respectively.

 In lower frequency, these sensors which have maximum 4.0 Vpp voltage may use as strain sensor, vibration sensor, atomic force microscope cantilever piezoelectric sensor, etc. Within the scope of this project, for the first time, the local piezoelectric sensors are fabricated, and a PLC based hydraulic pressure system is designed to produce them in Turkey.



Project Number        Foundation      Subject                                                                  


   2015-127              SRPC               Piezoelectric Sensors Vibration Characterization by a Digital Measurement System                                                                                  Based on Laser (Completed)



Nowadays, piezoelectric sensors are used in many areas such as health monitoring of steel structures using thickness modes study of piezoelectric patches, in electricity storage systems for power harvesting by converting a mechanical energy into an electrical one, in monitoring a body structure of aircrafts, in the moving parts of the mechatronics systems. The piezoelectric sensors also are used in such voice stimulators as a buzzer, microphones, head phones, for pressure measurement, in the underwater wireless ultrasonic communication, and in the medical equipment.  


This project describes the innovative design of a digital measurement system based on a laser displacement sensor as a vibrometer. This laser displacement sensor is capable to measure a dynamic displacement response dependence on a stimulated vibration. The frequency response of a piezoelectric disc is obtained by proccessing the inpu/output signals obtained from the function generator and digitizer cards driven by a personel computer. Resonant frequencies of vibration are achieved utilizing the sweep-sine signal excitation following the peak values in the signal response measured by laser displacement sensor. The results of the resonance frequency together with the maximum displacement measurements highly depend on the fixation of the piezoelectric disc. The test measurement results show that the system can distinguish resonance frequencies of pizeoelectric discs up to 20 Mhz with the resolution 1 Hz. Also, piezoelectric disc’s piezoelectric coefficient-d33  and its linearity along the excited voltage amplitudes have been calculated by the applied methods. The results obtained are in the compliance with the reference value declared by the manufacturer of piezoelectric disc.


Another objective of this project is to determine a basic mathematical modelling of piezoelectric disc vibration using a single degree freedom mechanical model, with estimation of its elasticity modulus. Consistency between the mathematical modelling and experimental values have been observed from 97 to 80 % between excitation amplitudes of 0.5 and 3.5 V when the mathematical modelling of piezoelectric disc is normally taken into  consideration with a linear working range. There are adverse effects associated with the piezoelectric disc which typically include the nonlinear dynamics of the hysteresis, saturation and the linear vibration dynamics. If the piezoelectric disc exposed to the exciting voltage over 3.5V, the nonlinear conditions occur due to its limited capacity. In the nonlinear working environment the mentioned adverse effects on piezoelectric disc cause the loss of performance, resonance frequency shifting. Eventually, the piezoelectric disc may be damaged. The obtained mathematical modelling is valuable not only for elasticity charaterization of the piezoelectric disc but also for definations of both linear and nonlinear working conditions of piezo based materilas.