Rozina Steigmann - Academia.edu (original) (raw)

Papers by Rozina Steigmann

Mg alloys have been designed to meet the requirements of bone repair implant materials by adding ... more Mg alloys have been designed to meet the requirements of bone repair implant materials by adding Calcium and Yttrium. Usually Ca is added to control corrosion rate of Mg alloys and thinning grain boundaries. The system is defined as Mg-0.5Ca-xY (x=0.5, 1, 1.5), varying the Y concentration in order to slow the degradation process. This morphological characterization with SEM, EDX, noninvasive testing is required to be carried out the determination of mechanical characteristics. The paper present the influence of Yttrium over elastic properties of these alloys in order to choose the best values appropriate with human bones, using Resonant Ultrasound Spectroscopy and ultrasound method.

Metamaterials are special one-, twoor three-dimensional artificial structures with electromagneti... more Metamaterials are special one-, twoor three-dimensional artificial structures with electromagnetic properties generally not found in the nature. Due to the simultaneous negative values of permittivity (ɛ) and permeability (μ), the wave vector and the vectors of electricand magnetic-field intensity form a left-handed triplet with the result of antiparallel phase and group velocity and back wave propagation [1]. These unique properties of the left-handed materials have allowed novel applications and devices to be developed [2]. This paper is devoted to the application of metamaterials to the design of microwave sensor for dielectric properties of any solid sample detection. The sensor was projected based on the metamaterial structure consisting of the split ring resonators (SRR) etched on the appropriate dielectric substrate. The most interesting application of SRR is due to its resonant nature and strong response on applied electromagnetic field [3]. Using this characteristic the die...

The paper present the possibility to use a sensor with metamaterial lens for the nondestructive e... more The paper present the possibility to use a sensor with metamaterial lens for the nondestructive evaluation of metallic strip gratings and carbon fiber reinforced plastics. The sensor has enhanced spatial resolution due to the apparition of evanescent waves in the space between strips and respectively between carbon fibers at the excitation with a transversal magnetic along z axis polarized electromagnetic field. The evanescent waves can be manipulated by a lens made from two conical Swiss rolls that act as a field concentrator. The detection is made with spatial resolution better than λ/2000.

IOP Conference Series: Materials Science and Engineering, 2020

Materiale Plastice, 2018

Composites made from metallic fillers embedded in polymer matrix have good shielding properties a... more Composites made from metallic fillers embedded in polymer matrix have good shielding properties as electrical point of view and tribology properties from mechanical point of view. These properties depend on amounts, shapes, sizes, and combinations of fillers and matrix. This paper proposes an electromagnetic method for determination of metallic fillers concentration in composite materials from metallic fillers embedded in polyester matrix. The bulk resistivity and dielectric permittivity were measured but these measurements are less influenced by the fillers concentration. The amplitude measurement of e.m.f induced in the reception coil of the focalized electromagnetic transducer and their averaging for the scanning of a relative large zone of the composite has proven to be an efficient method. The average amplitude linearly decreases with the increasing of fillers concentration, and has different values for Cu and AISI 316 fillers.

Advanced Materials Research, 2020

The paper proposes to present the results of the evaluation of glass fiber reinforced plastics (G... more The paper proposes to present the results of the evaluation of glass fiber reinforced plastics (GFRP) used in the construction of wind turbine blades. In a wind turbine, the blades are the most exposed to damages and the defects which appear are various and are connected with the type of manufacture, simple/complex loading, environmental conditions etc. In order to increase the lifetime span and to analyze the degradation phenomena during the materials functioning, destructive evaluation tests are performed to determine the mechanical property, by testing pure shear on specimens Iosipescu, from GFRP with woven reinforcement at [± 45°] and [0°/90°], with the shear fixture, endowment of Technical University Gh.Asachi Iasi.

Matéria (Rio de Janeiro), 2018

In this work the reversion of the strain-induced '-martensite to '-austenite was studied in a s... more In this work the reversion of the strain-induced '-martensite to '-austenite was studied in a series of AISI 316 stainless steels (SS) specimens. The samples were submitted to 63% reduction in thickness by rolling at a temperature of-70ºC, to achieve high martensite content. The reversion of martensite to austenite was made by means of isochronic, isothermal heat treatments at temperatures between 200 and 900ºC, so as to induce partial martensite-austenite phase transformation. The samples were studied by optical and electronic microscopy, X-ray diffraction, magnetization measurements, microhardness, and electromagnetic non destructive methods: feritscope, conductivity measurements using Van der Pauw's technique, and magnetic permeability assessments by an eddy current inverse method. The metalography study showed an ' lath martensite type structure and a similar one for the reverted austenite ('). Magnetization measurements and magnetic permeability showed that the reversion is active between 400 and 800°C. From the magnetic saturation measurements, a new calibration curve for the assessment of %' through the feritscope readings was obtained. The results of the different techniques were compared, in order to assess the scope of the studied techniques in the characterization of rolled SS products, and in the evaluation of progress of reversion reaction.

IOP Conference Series: Materials Science and Engineering, 2018

The paper proposes the use a metamaterial structure for improving the transmission properties of ... more The paper proposes the use a metamaterial structure for improving the transmission properties of open waveguide probe, developing a frequency selective sensor in microwave frequency X band sensitive to changing of properties of investigated dielectric material. This assembly can be used for properties of dielectric material investigation. The numerical simulations of electromagnetic wave propagation in rectangular waveguide with metamaterial structure were performed using the FEM and FDTD. The numerical results were proved with experiments, testing two types of biological materials.

MATEC Web of Conferences, 2017

The most important part of wind turbine is the blade that must be tested during the fabrication a... more The most important part of wind turbine is the blade that must be tested during the fabrication and during the functioning when can be damaged by moisture absorption, fatigue, wind gusts or lightning strikes. The novelty of the paper is represented by the employing of wireless sensors embedded in a scalable wind turbine blade made from Glass Fiber Reinforced Plastics together with Fiber Bragg Gratings in order to effectuate structural health monitoring in static conditions. The sensors are placed on critical location on blade determined by FEM simulation and a comparison between the complementary methods is done.

IOP Conference Series: Materials Science and Engineering, 2016

The paper analyses the elasto-plastic behavior of ten samples of E355 steel pipe of the same inne... more The paper analyses the elasto-plastic behavior of ten samples of E355 steel pipe of the same inner diameter, but with wall thickness ranging between 1.100 and 2.500 mm and length about 100 mm. The samples were subjected to variable internal pressure which was increased from 0 to 600-800 bar (up to the breaking of the pipe), being used the hydraulic oil, type HM46. The outer diameter of the tested pipes was measured successive for each increase of pressure with 100 bars, thus being determined the flow curve of the pipe material characterized by the elasto-plastic behavior and a tenacious failure. It was found that thin pipes, with the ratio between the inner and outer diameter less than 1.1, shows a different flow curve compare to pipes with thick walls, having the ratio between the inner and outer diameter greater than 1.1, the deformations being about two times higher. The rheological models of each type of pipes were identified.

IOP Conference Series: Materials Science and Engineering, 2016

In this paper, we investigate the cholesterol sensors consisting of a mixture of cholesterol oxid... more In this paper, we investigate the cholesterol sensors consisting of a mixture of cholesterol oxidase (ChOx) and zinc oxide (ZnO) nanoparticles were grown on ITO/glass substrates by vacuum thermal evaporation method and their sensing characteristics are examined in air. Also, the interest in surface waves appeared due to evanescent waves in the metallic strip grating in sub-wavelength regime. Before testing the transducer with metamaterials lens in the sub-wavelength regime, a simulation of the evanescent wave's formation has been performed at the edge of Ag strips, with thicknesses in the range of micrometers.

IOP Conference Series: Materials Science and Engineering, 2016

CFRP have applications among most different domains due their low density, high elastic modulus a... more CFRP have applications among most different domains due their low density, high elastic modulus and high ultimate strength along the carbon fibers direction, no fatigue and the expansion coefficient is small. This paper presents the behavior of carbon fiber woven-PPS composites at low velocity impacts. The transversal electrical conductivity is modified due to the plastic deformation following the impacts, and thus electromagnetic procedures can be used for assessment of CFRP using a high resolution sensor with metamaterials lens and comparing the results with those obtained from ultrasound testing with phased array sensor. The area of the delamination is overestimated when the method of phased array ultrasound is used and substantially underestimated by the electromagnetic testing. There were a good agreement between the simulations with finite element method and experimental measurements.

AIP Conference Proceedings, 2005

ABSTRACT

Journal of Clean Energy Technologies, 2016

Wind turbine blades (WTB) are one of the most damageable components of a wind turbine system and ... more Wind turbine blades (WTB) are one of the most damageable components of a wind turbine system and due to their importance must be tested during the fabrication and before installing. WTB are produced from composite materials with polymeric matrices, most of the stages of producing are manufacturing and can result in different types of defects. Therefore, non-destructive testing (NDT) techniques that provide surface and internal information of the blade are required. In this paper, ultrasonic testing using noncontact transducers for the control of composites type Glass Fiber Reinforced Plastics (GFRP) with orthophthalic polyester resins matrix is presented in order to prove its capabilities for such applications. The mechanical properties determined by above mentioned method are confirmed by destructive tests using Dynamic Mechanical Analysis.

Proceedings of the 6th International Conference on Emerging Technologies in Non-Destructive Testing (Brussels, Belgium, 27-29 May 2015), 2015

The current stage of non-destructive evaluation techniques imposes the development of new electro... more The current stage of non-destructive evaluation techniques imposes the development of new electromagnetic methods that are based on high spatial resolution and increased sensitivity. Printed circuit boards, integrated circuit boards, composite materials with polymeric matrix containing conductive fibers, as well as some types of biosensors are devices of interest in using such evaluation methods. In order to achieve high performance, the work frequencies must be either radiofrequencies or microwaves. At these frequencies, at the dielectric/conductor interface, plasmon polaritons can appear, propagating between conductive regions as evanescent waves. Detection of these waves, containing required information, can be done using sensors with metamaterial lenses. We propose in this paper the enhancement of the spatial resolution using electromagnetic methods, which can be accomplished in this case using evanescent waves that appear in the current study in slits of materials such as the spaces between carbon fibers in Carbon Fibers Reinforced Plastics or in materials of interest

This paper presents the results obtained at nondestructive examination of unirradiated pressure t... more This paper presents the results obtained at nondestructive examination of unirradiated pressure tubes (PT) samples with artificial discontinuities, the probabilities of detection/evaluation being determined and a model for life/maintenance time prediction based on hidden Markov chains. 1.

Zr 2.5%Nb alloys have wide utilization in nuclear energy engineering, being used at the fabricati... more Zr 2.5%Nb alloys have wide utilization in nuclear energy engineering, being used at the fabrication of pressure tubes from Pressurized Heavy Water Reactors (PHWR). This paper proposes to present an electromagnetic method for determination of diffused hydrogen/deuterium content based on the measurement of conductivity, correlating the theoretical results with those experimental obtained on samples cropped from non-irradiated pressure tubes. The methods can be used directly, the results being obtained by data inversion.

OR Insight

This paper presents an eddy current non-destructive evaluation (NDE) method to locate unique and ... more This paper presents an eddy current non-destructive evaluation (NDE) method to locate unique and multiple discontinuities of plate conductive materials using an eddy current sensor array, made up from an emission coil andseveral reception coils. The procedure of signal post-processing is a variant of the 'maximum likelihood' super resolution method.

Mg alloys have been designed to meet the requirements of bone repair implant materials by adding ... more Mg alloys have been designed to meet the requirements of bone repair implant materials by adding Calcium and Yttrium. Usually Ca is added to control corrosion rate of Mg alloys and thinning grain boundaries. The system is defined as Mg-0.5Ca-xY (x=0.5, 1, 1.5), varying the Y concentration in order to slow the degradation process. This morphological characterization with SEM, EDX, noninvasive testing is required to be carried out the determination of mechanical characteristics. The paper present the influence of Yttrium over elastic properties of these alloys in order to choose the best values appropriate with human bones, using Resonant Ultrasound Spectroscopy and ultrasound method.

Metamaterials are special one-, twoor three-dimensional artificial structures with electromagneti... more Metamaterials are special one-, twoor three-dimensional artificial structures with electromagnetic properties generally not found in the nature. Due to the simultaneous negative values of permittivity (ɛ) and permeability (μ), the wave vector and the vectors of electricand magnetic-field intensity form a left-handed triplet with the result of antiparallel phase and group velocity and back wave propagation [1]. These unique properties of the left-handed materials have allowed novel applications and devices to be developed [2]. This paper is devoted to the application of metamaterials to the design of microwave sensor for dielectric properties of any solid sample detection. The sensor was projected based on the metamaterial structure consisting of the split ring resonators (SRR) etched on the appropriate dielectric substrate. The most interesting application of SRR is due to its resonant nature and strong response on applied electromagnetic field [3]. Using this characteristic the die...

The paper present the possibility to use a sensor with metamaterial lens for the nondestructive e... more The paper present the possibility to use a sensor with metamaterial lens for the nondestructive evaluation of metallic strip gratings and carbon fiber reinforced plastics. The sensor has enhanced spatial resolution due to the apparition of evanescent waves in the space between strips and respectively between carbon fibers at the excitation with a transversal magnetic along z axis polarized electromagnetic field. The evanescent waves can be manipulated by a lens made from two conical Swiss rolls that act as a field concentrator. The detection is made with spatial resolution better than λ/2000.

IOP Conference Series: Materials Science and Engineering, 2020

Materiale Plastice, 2018

Composites made from metallic fillers embedded in polymer matrix have good shielding properties a... more Composites made from metallic fillers embedded in polymer matrix have good shielding properties as electrical point of view and tribology properties from mechanical point of view. These properties depend on amounts, shapes, sizes, and combinations of fillers and matrix. This paper proposes an electromagnetic method for determination of metallic fillers concentration in composite materials from metallic fillers embedded in polyester matrix. The bulk resistivity and dielectric permittivity were measured but these measurements are less influenced by the fillers concentration. The amplitude measurement of e.m.f induced in the reception coil of the focalized electromagnetic transducer and their averaging for the scanning of a relative large zone of the composite has proven to be an efficient method. The average amplitude linearly decreases with the increasing of fillers concentration, and has different values for Cu and AISI 316 fillers.

Advanced Materials Research, 2020

The paper proposes to present the results of the evaluation of glass fiber reinforced plastics (G... more The paper proposes to present the results of the evaluation of glass fiber reinforced plastics (GFRP) used in the construction of wind turbine blades. In a wind turbine, the blades are the most exposed to damages and the defects which appear are various and are connected with the type of manufacture, simple/complex loading, environmental conditions etc. In order to increase the lifetime span and to analyze the degradation phenomena during the materials functioning, destructive evaluation tests are performed to determine the mechanical property, by testing pure shear on specimens Iosipescu, from GFRP with woven reinforcement at [± 45°] and [0°/90°], with the shear fixture, endowment of Technical University Gh.Asachi Iasi.

Matéria (Rio de Janeiro), 2018

In this work the reversion of the strain-induced '-martensite to '-austenite was studied in a s... more In this work the reversion of the strain-induced '-martensite to '-austenite was studied in a series of AISI 316 stainless steels (SS) specimens. The samples were submitted to 63% reduction in thickness by rolling at a temperature of-70ºC, to achieve high martensite content. The reversion of martensite to austenite was made by means of isochronic, isothermal heat treatments at temperatures between 200 and 900ºC, so as to induce partial martensite-austenite phase transformation. The samples were studied by optical and electronic microscopy, X-ray diffraction, magnetization measurements, microhardness, and electromagnetic non destructive methods: feritscope, conductivity measurements using Van der Pauw's technique, and magnetic permeability assessments by an eddy current inverse method. The metalography study showed an ' lath martensite type structure and a similar one for the reverted austenite ('). Magnetization measurements and magnetic permeability showed that the reversion is active between 400 and 800°C. From the magnetic saturation measurements, a new calibration curve for the assessment of %' through the feritscope readings was obtained. The results of the different techniques were compared, in order to assess the scope of the studied techniques in the characterization of rolled SS products, and in the evaluation of progress of reversion reaction.

IOP Conference Series: Materials Science and Engineering, 2018

The paper proposes the use a metamaterial structure for improving the transmission properties of ... more The paper proposes the use a metamaterial structure for improving the transmission properties of open waveguide probe, developing a frequency selective sensor in microwave frequency X band sensitive to changing of properties of investigated dielectric material. This assembly can be used for properties of dielectric material investigation. The numerical simulations of electromagnetic wave propagation in rectangular waveguide with metamaterial structure were performed using the FEM and FDTD. The numerical results were proved with experiments, testing two types of biological materials.

MATEC Web of Conferences, 2017

The most important part of wind turbine is the blade that must be tested during the fabrication a... more The most important part of wind turbine is the blade that must be tested during the fabrication and during the functioning when can be damaged by moisture absorption, fatigue, wind gusts or lightning strikes. The novelty of the paper is represented by the employing of wireless sensors embedded in a scalable wind turbine blade made from Glass Fiber Reinforced Plastics together with Fiber Bragg Gratings in order to effectuate structural health monitoring in static conditions. The sensors are placed on critical location on blade determined by FEM simulation and a comparison between the complementary methods is done.

IOP Conference Series: Materials Science and Engineering, 2016

The paper analyses the elasto-plastic behavior of ten samples of E355 steel pipe of the same inne... more The paper analyses the elasto-plastic behavior of ten samples of E355 steel pipe of the same inner diameter, but with wall thickness ranging between 1.100 and 2.500 mm and length about 100 mm. The samples were subjected to variable internal pressure which was increased from 0 to 600-800 bar (up to the breaking of the pipe), being used the hydraulic oil, type HM46. The outer diameter of the tested pipes was measured successive for each increase of pressure with 100 bars, thus being determined the flow curve of the pipe material characterized by the elasto-plastic behavior and a tenacious failure. It was found that thin pipes, with the ratio between the inner and outer diameter less than 1.1, shows a different flow curve compare to pipes with thick walls, having the ratio between the inner and outer diameter greater than 1.1, the deformations being about two times higher. The rheological models of each type of pipes were identified.

IOP Conference Series: Materials Science and Engineering, 2016

In this paper, we investigate the cholesterol sensors consisting of a mixture of cholesterol oxid... more In this paper, we investigate the cholesterol sensors consisting of a mixture of cholesterol oxidase (ChOx) and zinc oxide (ZnO) nanoparticles were grown on ITO/glass substrates by vacuum thermal evaporation method and their sensing characteristics are examined in air. Also, the interest in surface waves appeared due to evanescent waves in the metallic strip grating in sub-wavelength regime. Before testing the transducer with metamaterials lens in the sub-wavelength regime, a simulation of the evanescent wave's formation has been performed at the edge of Ag strips, with thicknesses in the range of micrometers.

IOP Conference Series: Materials Science and Engineering, 2016

CFRP have applications among most different domains due their low density, high elastic modulus a... more CFRP have applications among most different domains due their low density, high elastic modulus and high ultimate strength along the carbon fibers direction, no fatigue and the expansion coefficient is small. This paper presents the behavior of carbon fiber woven-PPS composites at low velocity impacts. The transversal electrical conductivity is modified due to the plastic deformation following the impacts, and thus electromagnetic procedures can be used for assessment of CFRP using a high resolution sensor with metamaterials lens and comparing the results with those obtained from ultrasound testing with phased array sensor. The area of the delamination is overestimated when the method of phased array ultrasound is used and substantially underestimated by the electromagnetic testing. There were a good agreement between the simulations with finite element method and experimental measurements.

AIP Conference Proceedings, 2005

ABSTRACT

Journal of Clean Energy Technologies, 2016

Wind turbine blades (WTB) are one of the most damageable components of a wind turbine system and ... more Wind turbine blades (WTB) are one of the most damageable components of a wind turbine system and due to their importance must be tested during the fabrication and before installing. WTB are produced from composite materials with polymeric matrices, most of the stages of producing are manufacturing and can result in different types of defects. Therefore, non-destructive testing (NDT) techniques that provide surface and internal information of the blade are required. In this paper, ultrasonic testing using noncontact transducers for the control of composites type Glass Fiber Reinforced Plastics (GFRP) with orthophthalic polyester resins matrix is presented in order to prove its capabilities for such applications. The mechanical properties determined by above mentioned method are confirmed by destructive tests using Dynamic Mechanical Analysis.

Proceedings of the 6th International Conference on Emerging Technologies in Non-Destructive Testing (Brussels, Belgium, 27-29 May 2015), 2015

The current stage of non-destructive evaluation techniques imposes the development of new electro... more The current stage of non-destructive evaluation techniques imposes the development of new electromagnetic methods that are based on high spatial resolution and increased sensitivity. Printed circuit boards, integrated circuit boards, composite materials with polymeric matrix containing conductive fibers, as well as some types of biosensors are devices of interest in using such evaluation methods. In order to achieve high performance, the work frequencies must be either radiofrequencies or microwaves. At these frequencies, at the dielectric/conductor interface, plasmon polaritons can appear, propagating between conductive regions as evanescent waves. Detection of these waves, containing required information, can be done using sensors with metamaterial lenses. We propose in this paper the enhancement of the spatial resolution using electromagnetic methods, which can be accomplished in this case using evanescent waves that appear in the current study in slits of materials such as the spaces between carbon fibers in Carbon Fibers Reinforced Plastics or in materials of interest

This paper presents the results obtained at nondestructive examination of unirradiated pressure t... more This paper presents the results obtained at nondestructive examination of unirradiated pressure tubes (PT) samples with artificial discontinuities, the probabilities of detection/evaluation being determined and a model for life/maintenance time prediction based on hidden Markov chains. 1.

Zr 2.5%Nb alloys have wide utilization in nuclear energy engineering, being used at the fabricati... more Zr 2.5%Nb alloys have wide utilization in nuclear energy engineering, being used at the fabrication of pressure tubes from Pressurized Heavy Water Reactors (PHWR). This paper proposes to present an electromagnetic method for determination of diffused hydrogen/deuterium content based on the measurement of conductivity, correlating the theoretical results with those experimental obtained on samples cropped from non-irradiated pressure tubes. The methods can be used directly, the results being obtained by data inversion.

OR Insight

This paper presents an eddy current non-destructive evaluation (NDE) method to locate unique and ... more This paper presents an eddy current non-destructive evaluation (NDE) method to locate unique and multiple discontinuities of plate conductive materials using an eddy current sensor array, made up from an emission coil andseveral reception coils. The procedure of signal post-processing is a variant of the 'maximum likelihood' super resolution method.