Naim Derebasi - Academia.edu (original) (raw)

Papers by Naim Derebasi

Research paper thumbnail of GMI effect in CuO coated Co-based amorphous ribbons

Journal of Alloys and Compounds, 2009

A Copper oxide (CuO) film has been grown on a surface of Co-based amorphous ribbon using chemical... more A Copper oxide (CuO) film has been grown on a surface of Co-based amorphous ribbon using chemical successive ionic layer adsorption and reaction technique, at room temperature and atmosphere pressure. The influence of coating and width of ribbon on giant magneto impedance have been investigated over a frequency range from 0.1 to 3 MHz and under a static magnetic field between −8 and +8 kA/m. The results showed that Co-based amorphous ribbons, which are coated CuO film, have a significant effect on the magnitude and operation frequency for the giant magneto impedance effect as compared to the samples without coating. The highest giant magneto impedance effect was found to be 14.90 on 5 mm width coated ribbon, which is 60% higher than the sample without coating. A surface observation of these samples has been carried out by an atomic force microscope. The AFM images reveal the difference between surfaces of coated and as-cast sample. .tr (A. Peksoz). This paper is concentrated on the GMI effect to understand the influence of coating, geometrical factors and surface roughness of Co-based amorphous ribbons.

Research paper thumbnail of Giant Magneto–Impedance Effect in Thin Zinc Oxide Coated on Co-Based (2705 X) Amorphous Ribbons

IEEE Transactions on Magnetics, 2010

ZnO film coated Co-based (2705 X) amorphous ribbons are prepared by the successive ionic layer ad... more ZnO film coated Co-based (2705 X) amorphous ribbons are prepared by the successive ionic layer adsorption and reaction technique. The influence of coating on giant magneto-impedance (GMI) has been investigated over a frequency range from 0.1 to 3.5 MHz and under a static magnetic field between 8 and +8 kA/m. The highest GMI ratio of 15.63% was obtained in the coated Co-based amorphous ribbons which is 80% higher than the sample without coating. The results indicate that the surface coating process plays an important role in the GMI effect.

Research paper thumbnail of Influence of cutting stress on magnetic field and flux density distribution in non-oriented electrical steels

Journal of Magnetism and Magnetic Materials, 2000

Magnetic properties of sheets of electrical steel with di!erent permeability, grain size and sili... more Magnetic properties of sheets of electrical steel with di!erent permeability, grain size and silicon content were measured before and after cutting into strips. Cutting caused a reduction in permeability and the degraded area close to the cut edge. Silicon content was less in#uential than the grain size. The degraded area was found to be up to 15 mm depending on the type of material.

Research paper thumbnail of Large gyromagnetic effect in as-cast and post-production treated amorphous wires

Sensors and Actuators A-physical, 2003

The large gyromagnetic effect (LGE) in highly positive magnetostrictive Fe 77.5 Si 7.5 B 15 amorp... more The large gyromagnetic effect (LGE) in highly positive magnetostrictive Fe 77.5 Si 7.5 B 15 amorphous as-cast, furnace annealed with and without axial tension, current annealed, and transverse field annealed wires was investigated. A slight decrease in the rotation frequency of the LGE was observed in the annealed samples. Results on the influence of a localised dc bias field on the LGE of as-cast and furnace annealed samples are reported for the first time. The localised dc bias field applied along the length of the wires significantly influences both frequency and direction of the wires' rotation.

Research paper thumbnail of Computerised DC bridge method of thermistor measurement of localised power loss in magnetic materials

IEEE Transactions on Magnetics, 1992

A b s f r o c t L o c a l i s e d power loss is a n important criterion in understanding loss dis... more A b s f r o c t L o c a l i s e d power loss is a n important criterion in understanding loss distribution in various parts of large electrical machines. A thermistor and associated electronics were used to measure the localised power loss from the initial rate of rise of temperature in magnetic aterials. The designed system was calibrated by using ?R Joule loss obtained from a known dc current through a copper strip sample.

Research paper thumbnail of Effect of tension and surface properties on domain wall motion in amorphous materials

Journal of Magnetism and Magnetic Materials, 1994

Research paper thumbnail of Influence of scratching on domain structure and power loss in amorphous ribbons

IEEE Transactions on Magnetics, 1994

Abstrwt-Static domain observations were performed not only on polished and annealed samples but a... more Abstrwt-Static domain observations were performed not only on polished and annealed samples but also on scratched samples with different scratching intervals by using the Kerr effect technique. The domain observations and loss measurements were carried out on 2605SC amorphous ribbon under 20 MPa tension to emulate a typical condition in a 100 kVA transformer. Loss measurements were carried out using the initial rate of rise of temperature technique over a frequency range of SO to 400 Hz at flux densities from 0.8 to 1.4 Tesla The transverse scratching of the sample surface was very effective on decreasing domain wall spacing, The anomaly factor was also found to alter due to changes in the domain wall spacing. A scratching interval of 3 mm was found to be the optimum for maximum energy saving on surface treated amorphous ribbons.

Research paper thumbnail of Giant magneto-impedance effect in diamagnetic organic thin film coated amorphous ribbons

Sensors and Actuators A-physical, 2010

We grew a diamagnetic thin film on the surface of Co-based amorphous ribbon (Fe5.85Co70.15Mo4B15S... more We grew a diamagnetic thin film on the surface of Co-based amorphous ribbon (Fe5.85Co70.15Mo4B15Si5) to investigate the effect of this coating on giant magneto-impedance (GMI). We investigated GMI over a frequency range of 0.1–3.0MHz and under a static magnetic field. The results show that GMI for amorphous ribbons can be enhanced by this coating process. A changing in GMI as

Research paper thumbnail of Dynamic hysteresis modelling for nano-crystalline cores

Expert Systems With Applications, 2009

This paper presents an artificial neural network approach based on dynamic Preisach model to comp... more This paper presents an artificial neural network approach based on dynamic Preisach model to compute hysteresis loops of nano-crystalline cores. The network has been trained by a Levenberg-Marquardt learning algorithm. The model is fast and does not require tremendous computational efforts. The results obtained by using the proposed model are in good agreement with experimental results.

Research paper thumbnail of Aspects of the cut-edge effect stress on the power loss and flux density distribution in electrical steel sheets

Journal of Magnetism and Magnetic Materials, 2000

This paper describes some e!ects of cutting on power loss, localised #ux distribution and B}H cur... more This paper describes some e!ects of cutting on power loss, localised #ux distribution and B}H curves of a fully processed, high permeability non-oriented electrical steel. Cutting a single sheet into narrow strips increased the power loss by up to 30% and signi"cantly changed the B}H characteristics. The change in #ux distribution caused by cutting was lower when magnetised at 400 Hz than at 50 Hz.

Research paper thumbnail of A novel system for rapid measurement of high-frequency magnetic properties of toroidal cores of different sizes

Journal of Magnetism and Magnetic Materials, 2000

A novel system for power loss and B}H measurements on toroidal magnetic cores was built to operat... more A novel system for power loss and B}H measurements on toroidal magnetic cores was built to operate up to 200 kHz. Measurement data taken using sophisticated software at 10 MHz sampling rate and 16-bit resolution shows the system is versatile and can be used to test a wide range of core sizes and materials with an error ($3%.

Research paper thumbnail of Variation of magnetic properties of toroidal cores with magnetizing frequency

Journal of Magnetism and Magnetic Materials, 2000

AC magnetic properties of toroidal cores made from six di!erent soft magnetic materials were meas... more AC magnetic properties of toroidal cores made from six di!erent soft magnetic materials were measured. A solid steel core exhibited the highest remanance, coercivity and core loss as expected whereas a nanocrystalline core had the lowest remanance of the cores tested. Increase in dynamic core loss with frequency in steel particle and iron powder cores was low compared with the other cores but was low in permeability.

Research paper thumbnail of Mathematical model for cutting effect on magnetic flux distribution near the cut edge of non-oriented electrical steels

Computational Materials Science, 2008

Basic magnetic properties of non-oriented electrical steel sheets with different grain size and s... more Basic magnetic properties of non-oriented electrical steel sheets with different grain size and silicon content have different behaviour before and after cutting into strips. Cutting process causes a significant drop in flux density and deterioration of magnetic properties occurs over a region up to 10 mm from close to the cut edge. Therefore some degraded regions are formed at each side of the cut. A new mathematical model was formed for the degree of deterioration on flux distribution near the cut edge. The variation of magnetic induction in the cutting region was given as a function of four different parameters depending on the material. The model also included the variation of these parameters with the grain size and silicon content. It is observed that the change in the parameters until 2.5% Si content is not significant, while it has a remarkable variation for them after 2.5% Si content and similar effect was found to be for grain size. The mathematical model gives the degree to which the magnetic properties of the region around the edge degrade after the cutting process. The calculated results of the model showed good agreements with the experimental results.

Research paper thumbnail of Effect of stress on localised flux direction in amorphous toroidal transducers

Sensors and Actuators A-physical, 1997

... Article Outline. • References. ,,,,, ELSEVIER Sensors and Actuators A 59 (1997) 342..fi A Eff... more ... Article Outline. • References. ,,,,, ELSEVIER Sensors and Actuators A 59 (1997) 342..fi A Effect of stress on localised flux directions in amorphous toroidal transducers Naim Derebasi u., Turgut Meydan Uhulag Uail!ersity. Physics Deparrtaenl, 16059 Gorukle Bursa, Turkey h I Jl ...

Research paper thumbnail of Prediction of dynamic hysteresis loops of nano-crystalline cores

Expert Systems With Applications, 2009

Dynamic hysteresis loops of a range of nano-crystalline cores have been obtained over a wide freq... more Dynamic hysteresis loops of a range of nano-crystalline cores have been obtained over a wide frequency range (1-50 kHz). A dynamic hysteresis model from measurements using an artificial neural network trained by the delta-bar-delta learning algorithm has been developed. The input parameters include the geometrical dimensions of cores, peak magnetic induction and magnetizing frequency. The results show the neural network model has an acceptable estimation capability for dynamic hysteresis loops of toroidal nano-crystalline cores.

Research paper thumbnail of A neural network-based tool for magnetic performance prediction of toroidal cores

Journal of Magnetism and Magnetic Materials, 2003

Geometrical and building parameters have a strong influence on magnetic performance of wound toro... more Geometrical and building parameters have a strong influence on magnetic performance of wound toroidal cores made from electrical steel or similar strip products. This paper presents a neural network-based approach to predict losses and permeability in such cores of varying geometries over an induction range of 0.2-1.8 T (50 Hz). The approach is shown to be successful. r

Research paper thumbnail of Prediction of induction parameters on toroidal wound cores using neural network

Journal of Magnetism and Magnetic Materials, 2007

This paper presents a new approach based on neural network to predict the induction parameters of... more This paper presents a new approach based on neural network to predict the induction parameters of the toroidal wound cores. The input parameters were the geometrical dimensions of the toroidal core, frequency and magnetic flux density. A total of 3176 input vector from previously measured 52 varied dimensions and built 27M4 material toroidal samples were available in the training set to a backpropagation feed forward neural network. The sigmoid and hyperbolic tangent transfer functions and full connectivity were used in the hidden layers. The correlation coefficients for the total harmonic distortion and form factor were found to be 0.99 and 0.98, respectively after the network was trained.

Research paper thumbnail of Influence of bending stress on domain motion in amorphous material based magneto-elastic transducers

Journal of Magnetism and Magnetic Materials, 1992

Research paper thumbnail of Effect of surface roughness and tension on dynamic domain motion in grain oriented 3% silicon iron

Journal of Magnetism and Magnetic Materials, 1992

Research paper thumbnail of Sensitivity analysis for estimation of power losses in magnetic cores using neural network

Journal of Physics and Chemistry of Solids, 2006

Experimental data from a sample of 42 cores made from grain oriented 0.27 mm thick 3% SiFe electr... more Experimental data from a sample of 42 cores made from grain oriented 0.27 mm thick 3% SiFe electrical steel with dimensions ranging from 35 to 160 mm outer diameter, 25-100 mm inner diameter and 10-70 mm strip width and a flux density range 0.2-1.7 T have been obtained at 50 Hz and used as training data to a feed forward neural network. An analytical equation for prediction of power loss as depends on input parameters from the results of sensitivity analysis has been obtained. The calculated power losses with the analytical expression have also been compared with power loss obtained from the Preisach model after it has been applied to toroidal cores. The results show the proposed model can be used for estimation of power losses in the toroidal cores. r

Research paper thumbnail of GMI effect in CuO coated Co-based amorphous ribbons

Journal of Alloys and Compounds, 2009

A Copper oxide (CuO) film has been grown on a surface of Co-based amorphous ribbon using chemical... more A Copper oxide (CuO) film has been grown on a surface of Co-based amorphous ribbon using chemical successive ionic layer adsorption and reaction technique, at room temperature and atmosphere pressure. The influence of coating and width of ribbon on giant magneto impedance have been investigated over a frequency range from 0.1 to 3 MHz and under a static magnetic field between −8 and +8 kA/m. The results showed that Co-based amorphous ribbons, which are coated CuO film, have a significant effect on the magnitude and operation frequency for the giant magneto impedance effect as compared to the samples without coating. The highest giant magneto impedance effect was found to be 14.90 on 5 mm width coated ribbon, which is 60% higher than the sample without coating. A surface observation of these samples has been carried out by an atomic force microscope. The AFM images reveal the difference between surfaces of coated and as-cast sample. .tr (A. Peksoz). This paper is concentrated on the GMI effect to understand the influence of coating, geometrical factors and surface roughness of Co-based amorphous ribbons.

Research paper thumbnail of Giant Magneto–Impedance Effect in Thin Zinc Oxide Coated on Co-Based (2705 X) Amorphous Ribbons

IEEE Transactions on Magnetics, 2010

ZnO film coated Co-based (2705 X) amorphous ribbons are prepared by the successive ionic layer ad... more ZnO film coated Co-based (2705 X) amorphous ribbons are prepared by the successive ionic layer adsorption and reaction technique. The influence of coating on giant magneto-impedance (GMI) has been investigated over a frequency range from 0.1 to 3.5 MHz and under a static magnetic field between 8 and +8 kA/m. The highest GMI ratio of 15.63% was obtained in the coated Co-based amorphous ribbons which is 80% higher than the sample without coating. The results indicate that the surface coating process plays an important role in the GMI effect.

Research paper thumbnail of Influence of cutting stress on magnetic field and flux density distribution in non-oriented electrical steels

Journal of Magnetism and Magnetic Materials, 2000

Magnetic properties of sheets of electrical steel with di!erent permeability, grain size and sili... more Magnetic properties of sheets of electrical steel with di!erent permeability, grain size and silicon content were measured before and after cutting into strips. Cutting caused a reduction in permeability and the degraded area close to the cut edge. Silicon content was less in#uential than the grain size. The degraded area was found to be up to 15 mm depending on the type of material.

Research paper thumbnail of Large gyromagnetic effect in as-cast and post-production treated amorphous wires

Sensors and Actuators A-physical, 2003

The large gyromagnetic effect (LGE) in highly positive magnetostrictive Fe 77.5 Si 7.5 B 15 amorp... more The large gyromagnetic effect (LGE) in highly positive magnetostrictive Fe 77.5 Si 7.5 B 15 amorphous as-cast, furnace annealed with and without axial tension, current annealed, and transverse field annealed wires was investigated. A slight decrease in the rotation frequency of the LGE was observed in the annealed samples. Results on the influence of a localised dc bias field on the LGE of as-cast and furnace annealed samples are reported for the first time. The localised dc bias field applied along the length of the wires significantly influences both frequency and direction of the wires' rotation.

Research paper thumbnail of Computerised DC bridge method of thermistor measurement of localised power loss in magnetic materials

IEEE Transactions on Magnetics, 1992

A b s f r o c t L o c a l i s e d power loss is a n important criterion in understanding loss dis... more A b s f r o c t L o c a l i s e d power loss is a n important criterion in understanding loss distribution in various parts of large electrical machines. A thermistor and associated electronics were used to measure the localised power loss from the initial rate of rise of temperature in magnetic aterials. The designed system was calibrated by using ?R Joule loss obtained from a known dc current through a copper strip sample.

Research paper thumbnail of Effect of tension and surface properties on domain wall motion in amorphous materials

Journal of Magnetism and Magnetic Materials, 1994

Research paper thumbnail of Influence of scratching on domain structure and power loss in amorphous ribbons

IEEE Transactions on Magnetics, 1994

Abstrwt-Static domain observations were performed not only on polished and annealed samples but a... more Abstrwt-Static domain observations were performed not only on polished and annealed samples but also on scratched samples with different scratching intervals by using the Kerr effect technique. The domain observations and loss measurements were carried out on 2605SC amorphous ribbon under 20 MPa tension to emulate a typical condition in a 100 kVA transformer. Loss measurements were carried out using the initial rate of rise of temperature technique over a frequency range of SO to 400 Hz at flux densities from 0.8 to 1.4 Tesla The transverse scratching of the sample surface was very effective on decreasing domain wall spacing, The anomaly factor was also found to alter due to changes in the domain wall spacing. A scratching interval of 3 mm was found to be the optimum for maximum energy saving on surface treated amorphous ribbons.

Research paper thumbnail of Giant magneto-impedance effect in diamagnetic organic thin film coated amorphous ribbons

Sensors and Actuators A-physical, 2010

We grew a diamagnetic thin film on the surface of Co-based amorphous ribbon (Fe5.85Co70.15Mo4B15S... more We grew a diamagnetic thin film on the surface of Co-based amorphous ribbon (Fe5.85Co70.15Mo4B15Si5) to investigate the effect of this coating on giant magneto-impedance (GMI). We investigated GMI over a frequency range of 0.1–3.0MHz and under a static magnetic field. The results show that GMI for amorphous ribbons can be enhanced by this coating process. A changing in GMI as

Research paper thumbnail of Dynamic hysteresis modelling for nano-crystalline cores

Expert Systems With Applications, 2009

This paper presents an artificial neural network approach based on dynamic Preisach model to comp... more This paper presents an artificial neural network approach based on dynamic Preisach model to compute hysteresis loops of nano-crystalline cores. The network has been trained by a Levenberg-Marquardt learning algorithm. The model is fast and does not require tremendous computational efforts. The results obtained by using the proposed model are in good agreement with experimental results.

Research paper thumbnail of Aspects of the cut-edge effect stress on the power loss and flux density distribution in electrical steel sheets

Journal of Magnetism and Magnetic Materials, 2000

This paper describes some e!ects of cutting on power loss, localised #ux distribution and B}H cur... more This paper describes some e!ects of cutting on power loss, localised #ux distribution and B}H curves of a fully processed, high permeability non-oriented electrical steel. Cutting a single sheet into narrow strips increased the power loss by up to 30% and signi"cantly changed the B}H characteristics. The change in #ux distribution caused by cutting was lower when magnetised at 400 Hz than at 50 Hz.

Research paper thumbnail of A novel system for rapid measurement of high-frequency magnetic properties of toroidal cores of different sizes

Journal of Magnetism and Magnetic Materials, 2000

A novel system for power loss and B}H measurements on toroidal magnetic cores was built to operat... more A novel system for power loss and B}H measurements on toroidal magnetic cores was built to operate up to 200 kHz. Measurement data taken using sophisticated software at 10 MHz sampling rate and 16-bit resolution shows the system is versatile and can be used to test a wide range of core sizes and materials with an error ($3%.

Research paper thumbnail of Variation of magnetic properties of toroidal cores with magnetizing frequency

Journal of Magnetism and Magnetic Materials, 2000

AC magnetic properties of toroidal cores made from six di!erent soft magnetic materials were meas... more AC magnetic properties of toroidal cores made from six di!erent soft magnetic materials were measured. A solid steel core exhibited the highest remanance, coercivity and core loss as expected whereas a nanocrystalline core had the lowest remanance of the cores tested. Increase in dynamic core loss with frequency in steel particle and iron powder cores was low compared with the other cores but was low in permeability.

Research paper thumbnail of Mathematical model for cutting effect on magnetic flux distribution near the cut edge of non-oriented electrical steels

Computational Materials Science, 2008

Basic magnetic properties of non-oriented electrical steel sheets with different grain size and s... more Basic magnetic properties of non-oriented electrical steel sheets with different grain size and silicon content have different behaviour before and after cutting into strips. Cutting process causes a significant drop in flux density and deterioration of magnetic properties occurs over a region up to 10 mm from close to the cut edge. Therefore some degraded regions are formed at each side of the cut. A new mathematical model was formed for the degree of deterioration on flux distribution near the cut edge. The variation of magnetic induction in the cutting region was given as a function of four different parameters depending on the material. The model also included the variation of these parameters with the grain size and silicon content. It is observed that the change in the parameters until 2.5% Si content is not significant, while it has a remarkable variation for them after 2.5% Si content and similar effect was found to be for grain size. The mathematical model gives the degree to which the magnetic properties of the region around the edge degrade after the cutting process. The calculated results of the model showed good agreements with the experimental results.

Research paper thumbnail of Effect of stress on localised flux direction in amorphous toroidal transducers

Sensors and Actuators A-physical, 1997

... Article Outline. • References. ,,,,, ELSEVIER Sensors and Actuators A 59 (1997) 342..fi A Eff... more ... Article Outline. • References. ,,,,, ELSEVIER Sensors and Actuators A 59 (1997) 342..fi A Effect of stress on localised flux directions in amorphous toroidal transducers Naim Derebasi u., Turgut Meydan Uhulag Uail!ersity. Physics Deparrtaenl, 16059 Gorukle Bursa, Turkey h I Jl ...

Research paper thumbnail of Prediction of dynamic hysteresis loops of nano-crystalline cores

Expert Systems With Applications, 2009

Dynamic hysteresis loops of a range of nano-crystalline cores have been obtained over a wide freq... more Dynamic hysteresis loops of a range of nano-crystalline cores have been obtained over a wide frequency range (1-50 kHz). A dynamic hysteresis model from measurements using an artificial neural network trained by the delta-bar-delta learning algorithm has been developed. The input parameters include the geometrical dimensions of cores, peak magnetic induction and magnetizing frequency. The results show the neural network model has an acceptable estimation capability for dynamic hysteresis loops of toroidal nano-crystalline cores.

Research paper thumbnail of A neural network-based tool for magnetic performance prediction of toroidal cores

Journal of Magnetism and Magnetic Materials, 2003

Geometrical and building parameters have a strong influence on magnetic performance of wound toro... more Geometrical and building parameters have a strong influence on magnetic performance of wound toroidal cores made from electrical steel or similar strip products. This paper presents a neural network-based approach to predict losses and permeability in such cores of varying geometries over an induction range of 0.2-1.8 T (50 Hz). The approach is shown to be successful. r

Research paper thumbnail of Prediction of induction parameters on toroidal wound cores using neural network

Journal of Magnetism and Magnetic Materials, 2007

This paper presents a new approach based on neural network to predict the induction parameters of... more This paper presents a new approach based on neural network to predict the induction parameters of the toroidal wound cores. The input parameters were the geometrical dimensions of the toroidal core, frequency and magnetic flux density. A total of 3176 input vector from previously measured 52 varied dimensions and built 27M4 material toroidal samples were available in the training set to a backpropagation feed forward neural network. The sigmoid and hyperbolic tangent transfer functions and full connectivity were used in the hidden layers. The correlation coefficients for the total harmonic distortion and form factor were found to be 0.99 and 0.98, respectively after the network was trained.

Research paper thumbnail of Influence of bending stress on domain motion in amorphous material based magneto-elastic transducers

Journal of Magnetism and Magnetic Materials, 1992

Research paper thumbnail of Effect of surface roughness and tension on dynamic domain motion in grain oriented 3% silicon iron

Journal of Magnetism and Magnetic Materials, 1992

Research paper thumbnail of Sensitivity analysis for estimation of power losses in magnetic cores using neural network

Journal of Physics and Chemistry of Solids, 2006

Experimental data from a sample of 42 cores made from grain oriented 0.27 mm thick 3% SiFe electr... more Experimental data from a sample of 42 cores made from grain oriented 0.27 mm thick 3% SiFe electrical steel with dimensions ranging from 35 to 160 mm outer diameter, 25-100 mm inner diameter and 10-70 mm strip width and a flux density range 0.2-1.7 T have been obtained at 50 Hz and used as training data to a feed forward neural network. An analytical equation for prediction of power loss as depends on input parameters from the results of sensitivity analysis has been obtained. The calculated power losses with the analytical expression have also been compared with power loss obtained from the Preisach model after it has been applied to toroidal cores. The results show the proposed model can be used for estimation of power losses in the toroidal cores. r