Pub Date : 2021-02-01DOI: 10.1051/EPJAP/2021200249
J. Naceur, R. Ouertani, F. Jrad, S. Khamlich, W. Dimassi, R. Chtourou
In this paper, we report the photoelectrochemical performances of CdS nanoparticles (NPs) decorated TiO2 photoanodes. The TiO2 nanofiber arrays (NFAs) were fabricated into Titanium substrate by a hydrothermal method. Afterwards, the deposited TiO2 NFAs were decorated with CdS NPs by employing a successive ionic layer adsorption and reaction (SILAR) method. The obtained samples of CdS covered and uncovered TiO2 NFAs were characterized by X-ray diffraction, Scanning Electron Microscopy and UV-visible Diffuse Reflectance Spectroscopy. The size of the CdS nanoparticles increases with the number of SILAR cycles and leads to an additional broad absorption peak in the visible part of the spectrum. Consequently, the photo-electrochemical performance of the CdS decorated TiO2 was enhanced substantially resulting in a better electron-hole separation and transport. This enhancement has been discussed and assigned to a better sun light harvesting and an efficient charge transfer between the CdS nanoparticles and the TiO2 NFAs.
{"title":"Enhanced photoelectrochemical performance of TiO2 nanofiber arrays decorated with CdS nanoparticles via SILAR method","authors":"J. Naceur, R. Ouertani, F. Jrad, S. Khamlich, W. Dimassi, R. Chtourou","doi":"10.1051/EPJAP/2021200249","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200249","url":null,"abstract":"In this paper, we report the photoelectrochemical performances of CdS nanoparticles (NPs) decorated TiO2 photoanodes. The TiO2 nanofiber arrays (NFAs) were fabricated into Titanium substrate by a hydrothermal method. Afterwards, the deposited TiO2 NFAs were decorated with CdS NPs by employing a successive ionic layer adsorption and reaction (SILAR) method. The obtained samples of CdS covered and uncovered TiO2 NFAs were characterized by X-ray diffraction, Scanning Electron Microscopy and UV-visible Diffuse Reflectance Spectroscopy. The size of the CdS nanoparticles increases with the number of SILAR cycles and leads to an additional broad absorption peak in the visible part of the spectrum. Consequently, the photo-electrochemical performance of the CdS decorated TiO2 was enhanced substantially resulting in a better electron-hole separation and transport. This enhancement has been discussed and assigned to a better sun light harvesting and an efficient charge transfer between the CdS nanoparticles and the TiO2 NFAs.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83224900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.1051/EPJAP/2021200354
Imen Houiji, M. Mahdouani, Mahfoudh Raïssi, R. Bourguiga
Much research has been conducted to improve the performance of photovoltaic solar cells. Transparent conductive film and interconnection layers have a significant impact on the performance of photovoltaic cells. In this work, we analyze the experimental results obtained on tandem organic photovoltaic solar cells with simple inverted structures using silver nanowires AgNW as transparent conductive electrode (TE) and as interconnection layer (ICL) between PEDOT: PSS and ZnO. This type of contact leads to a strong ohmic contact in both sub-cells having P3HT: ICBA as the lower active layer and having PTB7: PC71BM (1: 1.5) as the upper active layer with a good complement of the absorption spectrum. To study the advantages of using AgNWs as an interconnection layer (PEDOT: PSS/AgNWs/ZnO) in tandem photovoltaic solar cells and as an anode and its impact on the performance of these organic cells, we have simulated the electrical characteristics obtained by these tandem organic photovoltaic cells using an equivalent circuit model. This model is based on a single diode model with five photovoltaic parameters. We therefore extracted all the physical parameters of the illuminated photovoltaic cell from its experimental characteristics (J–V), such as the diode saturation current density (J0 ), the series and shunt resistors (RS , RSh ), the ideality factor (n) and the photogenerated current density (JPh ). For this we have solved the analytical equations of the current density using Newton Raphson's method. The equations are derived from the single diode equivalent circuit proposed to simulate the measured current density as a function of the voltage of the manufactured tandem type organic solar cells. A good agreement was obtained between the theoretical model and the experimental electrical characteristics. This confirms that the use of AgNWs between PEDOT: PSS and ZnO as an interconnection layer in reverse geometry of these tandem devices, has improved the efficiency (PCE = 9.24%) and is proving to be an efficient recombination layer for tandem organic photovoltaic solar cells.
{"title":"Modeling and optimization of organic tandem photovoltaic solar cells using silver nanowires as electrode and interconnecting layer","authors":"Imen Houiji, M. Mahdouani, Mahfoudh Raïssi, R. Bourguiga","doi":"10.1051/EPJAP/2021200354","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200354","url":null,"abstract":"Much research has been conducted to improve the performance of photovoltaic solar cells. Transparent conductive film and interconnection layers have a significant impact on the performance of photovoltaic cells. In this work, we analyze the experimental results obtained on tandem organic photovoltaic solar cells with simple inverted structures using silver nanowires AgNW as transparent conductive electrode (TE) and as interconnection layer (ICL) between PEDOT: PSS and ZnO. This type of contact leads to a strong ohmic contact in both sub-cells having P3HT: ICBA as the lower active layer and having PTB7: PC71BM (1: 1.5) as the upper active layer with a good complement of the absorption spectrum. To study the advantages of using AgNWs as an interconnection layer (PEDOT: PSS/AgNWs/ZnO) in tandem photovoltaic solar cells and as an anode and its impact on the performance of these organic cells, we have simulated the electrical characteristics obtained by these tandem organic photovoltaic cells using an equivalent circuit model. This model is based on a single diode model with five photovoltaic parameters. We therefore extracted all the physical parameters of the illuminated photovoltaic cell from its experimental characteristics (J–V), such as the diode saturation current density (J0 ), the series and shunt resistors (RS , RSh ), the ideality factor (n) and the photogenerated current density (JPh ). For this we have solved the analytical equations of the current density using Newton Raphson's method. The equations are derived from the single diode equivalent circuit proposed to simulate the measured current density as a function of the voltage of the manufactured tandem type organic solar cells. A good agreement was obtained between the theoretical model and the experimental electrical characteristics. This confirms that the use of AgNWs between PEDOT: PSS and ZnO as an interconnection layer in reverse geometry of these tandem devices, has improved the efficiency (PCE = 9.24%) and is proving to be an efficient recombination layer for tandem organic photovoltaic solar cells.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78799412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.1051/EPJAP/2021200259
Sharaf Eddine Kramti, Jaouher Ben Ali, L. Saidi, M. Sayadi, M. Bouchouicha, Eric Bechhoefer
Condition monitoring of High-Speed Shaft Bearing (HSSB) in Wind Turbine Generators (WTGs) remains a challenging subject for industrial and academic studies. The investigation of mechanical vibration signals presents the most popular method in the literature. Consequently, this work involves a novel data-driven approach for direct HSSB prognosis using the vibration analysis. The proposed method is based on the computation of traditional statistical metrics derived both from the time-domain and frequency-domain via Spectral Kurtosis (SK). Then, the selection of the most suitable features was made using three metrics (monotonicity, trendability, prognosablity) to guarantee a better generalization of the trained Elman Neural Network (ENN). The validation of the proposed method was done using the benchmark of the center for Intelligent Maintenance Systems (IMS) for training and real measured Green Power Monitoring Systems (GPMS) data for testing. We have provided two links for downloading these data sets. The experimental results show that the proposed approach presents a powerful prediction tool. Comparative results with previous work show several advantages for the proposed combination of statistical metrics and ENN, such as the external prediction and real online estimation of the Remaining Useful Life (RUL). Also, some new practical findings are provided in the discussion.
{"title":"A neural network approach for improved bearing prognostics of wind turbine generators","authors":"Sharaf Eddine Kramti, Jaouher Ben Ali, L. Saidi, M. Sayadi, M. Bouchouicha, Eric Bechhoefer","doi":"10.1051/EPJAP/2021200259","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200259","url":null,"abstract":"Condition monitoring of High-Speed Shaft Bearing (HSSB) in Wind Turbine Generators (WTGs) remains a challenging subject for industrial and academic studies. The investigation of mechanical vibration signals presents the most popular method in the literature. Consequently, this work involves a novel data-driven approach for direct HSSB prognosis using the vibration analysis. The proposed method is based on the computation of traditional statistical metrics derived both from the time-domain and frequency-domain via Spectral Kurtosis (SK). Then, the selection of the most suitable features was made using three metrics (monotonicity, trendability, prognosablity) to guarantee a better generalization of the trained Elman Neural Network (ENN). The validation of the proposed method was done using the benchmark of the center for Intelligent Maintenance Systems (IMS) for training and real measured Green Power Monitoring Systems (GPMS) data for testing. We have provided two links for downloading these data sets. The experimental results show that the proposed approach presents a powerful prediction tool. Comparative results with previous work show several advantages for the proposed combination of statistical metrics and ENN, such as the external prediction and real online estimation of the Remaining Useful Life (RUL). Also, some new practical findings are provided in the discussion.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75008958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.1051/EPJAP/2021200349
Buren Duan, Haonan Zhang, Lizhi Wu, Zuohao Hua, Zijing Bao, N. Guo, Y. Ye, R. Shen
As a new concept of space propulsion system, laser-ablation propulsion has attracted more and more attention due to its characteristics of low power consumption, high specific impulse, variable and controllable thrust. With an aim to further raise up the movement velocity of plasma, we combine the laser with high-voltage electrostatic field to accelerate the Cu plasma induced by laser ablation. To demonstrate the acceleration characteristics of plasma under different electric field intensity, the plasma conductivity, plasma shockwave intensity and plasma plume movement process were tested using parallel electrode plate device, self-made torsion pendulum impulse test bench and high-speed ICCD camera. The results showed that the conductive current and impulse formed by the plasma obviously increased under the applied electric field. The images captured by high-speed ICCD camera showed the plasma cross-sectional area was 0.194 mm2 at 900 ns and 0.217 mm2 at 1600 ns when the electric field intensity was 0 V/mm. With the electric field intensity increased to 30 V/mm, the plasma cross-sectional area elevated to 0.280 mm2 at 900 ns and 0.288 mm2 at 1600 ns. The acquisitions prove that the idea of this paper is feasible and favorable, which provide a theoretical basis for the combination of laser ablation propulsion and electric field.
{"title":"Acceleration characteristics of laser ablation Cu plasma in the electrostatic field","authors":"Buren Duan, Haonan Zhang, Lizhi Wu, Zuohao Hua, Zijing Bao, N. Guo, Y. Ye, R. Shen","doi":"10.1051/EPJAP/2021200349","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200349","url":null,"abstract":"As a new concept of space propulsion system, laser-ablation propulsion has attracted more and more attention due to its characteristics of low power consumption, high specific impulse, variable and controllable thrust. With an aim to further raise up the movement velocity of plasma, we combine the laser with high-voltage electrostatic field to accelerate the Cu plasma induced by laser ablation. To demonstrate the acceleration characteristics of plasma under different electric field intensity, the plasma conductivity, plasma shockwave intensity and plasma plume movement process were tested using parallel electrode plate device, self-made torsion pendulum impulse test bench and high-speed ICCD camera. The results showed that the conductive current and impulse formed by the plasma obviously increased under the applied electric field. The images captured by high-speed ICCD camera showed the plasma cross-sectional area was 0.194 mm2 at 900 ns and 0.217 mm2 at 1600 ns when the electric field intensity was 0 V/mm. With the electric field intensity increased to 30 V/mm, the plasma cross-sectional area elevated to 0.280 mm2 at 900 ns and 0.288 mm2 at 1600 ns. The acquisitions prove that the idea of this paper is feasible and favorable, which provide a theoretical basis for the combination of laser ablation propulsion and electric field.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83260521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.1051/epjap/2021200325
Jin Yang, Zhenghao He, Zhuoyu Zhang, Yuchen Liu, Ming Yin
In order to optimize the shock wave generated by underwater pulsed discharge, the relationship between cavity parameters and shock wave propagation is further studied by three-dimensional numerical simulation. According to the sound pressure field distribution obtained by the simulation, the reflection of the shock wave by the reactor wall can be clearly observed. The reflected pressure wave will reach its maximum value and then gradually attenuate. The study also found that when the deposition energy is constant, when the initial radius of the arc channel increases from 0.1 mm to 2.5 mm, the maximum amplitude of the shock wave will increase from 0.22 × 105 Pa to 1.70 × 105 Pa. When the initial radius of the arc channel is constant, as the deposition energy increases, the time to radiate the shock wave becomes earlier, and the maximum amplitude of the shock wave will increase. This means that a higher pressure can be generated by increasing the input of the deposition energy. When the deposition energy is constant, a higher-pressure level can be obtained by increasing the initial radius of the channel. The excitation frequency also affects the shock wave amplitude. Higher excitation frequency can obtain higher pressure amplitude. These methods will increase the efficiency of underwater pulse discharge treatment of bacteria.
{"title":"Effect of cavity parameters on the propagation of shock wave generated by underwater pulsed discharge","authors":"Jin Yang, Zhenghao He, Zhuoyu Zhang, Yuchen Liu, Ming Yin","doi":"10.1051/epjap/2021200325","DOIUrl":"https://doi.org/10.1051/epjap/2021200325","url":null,"abstract":"In order to optimize the shock wave generated by underwater pulsed discharge, the relationship between cavity parameters and shock wave propagation is further studied by three-dimensional numerical simulation. According to the sound pressure field distribution obtained by the simulation, the reflection of the shock wave by the reactor wall can be clearly observed. The reflected pressure wave will reach its maximum value and then gradually attenuate. The study also found that when the deposition energy is constant, when the initial radius of the arc channel increases from 0.1 mm to 2.5 mm, the maximum amplitude of the shock wave will increase from 0.22 × 105 Pa to 1.70 × 105 Pa. When the initial radius of the arc channel is constant, as the deposition energy increases, the time to radiate the shock wave becomes earlier, and the maximum amplitude of the shock wave will increase. This means that a higher pressure can be generated by increasing the input of the deposition energy. When the deposition energy is constant, a higher-pressure level can be obtained by increasing the initial radius of the channel. The excitation frequency also affects the shock wave amplitude. Higher excitation frequency can obtain higher pressure amplitude. These methods will increase the efficiency of underwater pulse discharge treatment of bacteria.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86921522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1051/epjap/2020200283
Zhanfeng Guo, Yunna Sun, Yan Wang, Guangyuan Wang, Xutong Song, G. Ding
With the power level of diode-pumped solid-state laser (DPSSL) rising continuously, its thermal effect has become the main problem limiting the laser performance. In this paper, based on the heat distribution of diode partially end-pumped slab (Innoslab) laser, a shunt rectangular microchannel heat sink with locally enhanced heat dissipation is designed. Firstly, multi-stage parallel short channels are designed in the heat concentration area to enhance the solid-liquid heat exchange in this area, and the effects of structure and working conditions on its heat dissipation performance are investigated. Secondly, the copper layer is introduced into the end face of the low thermal conductivity crystal to form a high thermal conductivity path, which alleviates the heat accumulation inside the crystal. Under a certain condition, compared with the traditional liquid-cooled plate system, the maximum temperature of the laser crystal is reduced from 169.62 to 118.18 °C, the pressure drop is reduced by 66.75%, and the total mass of the system is reduced to 4.87% of the original system, which effectively improves the practical performance of the device.
{"title":"Design and simulation of locally enhanced microchannel heat sink for diode partially pumped slab laser","authors":"Zhanfeng Guo, Yunna Sun, Yan Wang, Guangyuan Wang, Xutong Song, G. Ding","doi":"10.1051/epjap/2020200283","DOIUrl":"https://doi.org/10.1051/epjap/2020200283","url":null,"abstract":"With the power level of diode-pumped solid-state laser (DPSSL) rising continuously, its thermal effect has become the main problem limiting the laser performance. In this paper, based on the heat distribution of diode partially end-pumped slab (Innoslab) laser, a shunt rectangular microchannel heat sink with locally enhanced heat dissipation is designed. Firstly, multi-stage parallel short channels are designed in the heat concentration area to enhance the solid-liquid heat exchange in this area, and the effects of structure and working conditions on its heat dissipation performance are investigated. Secondly, the copper layer is introduced into the end face of the low thermal conductivity crystal to form a high thermal conductivity path, which alleviates the heat accumulation inside the crystal. Under a certain condition, compared with the traditional liquid-cooled plate system, the maximum temperature of the laser crystal is reduced from 169.62 to 118.18 °C, the pressure drop is reduced by 66.75%, and the total mass of the system is reduced to 4.87% of the original system, which effectively improves the practical performance of the device.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84416193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-16DOI: 10.1051/epjap/2020200320
Houaida Becharguia, M. Mahdouani, R. Bourguiga
In this paper, we have study two types of thin-film organic transistors and their application to release the organic inverter. For manufacturing p-type and n-type organic thin film transistors (OTFT), pentacene and N,N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13H27) have been used as organic semiconductors active layers. These organic thin film transistors have been shown excellent ambipolar operation. We proceeded initially to model and study these complementary organic transistors individually. Therefore we present the various electrical parameters resulting from the modeling of these two types of organic transistors (n-type and p-type) as well as the various parameters characterizing the organic inverter. Very good agreement is obtained between the experimental electrical characteristics of the two types of organic transistors and the characteristics obtained by the analytical model, as well as the experimental characteristics of the organic inverter thus produced.
{"title":"Modeling of two complementary ambipolar organic thin film transistors: application to organic inverter","authors":"Houaida Becharguia, M. Mahdouani, R. Bourguiga","doi":"10.1051/epjap/2020200320","DOIUrl":"https://doi.org/10.1051/epjap/2020200320","url":null,"abstract":"In this paper, we have study two types of thin-film organic transistors and their application to release the organic inverter. For manufacturing p-type and n-type organic thin film transistors (OTFT), pentacene and N,N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13H27) have been used as organic semiconductors active layers. These organic thin film transistors have been shown excellent ambipolar operation. We proceeded initially to model and study these complementary organic transistors individually. Therefore we present the various electrical parameters resulting from the modeling of these two types of organic transistors (n-type and p-type) as well as the various parameters characterizing the organic inverter. Very good agreement is obtained between the experimental electrical characteristics of the two types of organic transistors and the characteristics obtained by the analytical model, as well as the experimental characteristics of the organic inverter thus produced.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2020-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77689259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-08DOI: 10.1051/epjap/2020200277
Mojtaba Sarafpour, I. Ebrahimi, Nadia Rahimi Tanha
Various methods have been used by the researchers in order to improve the interfacial adhesion of para aramid fibers. In the present research, poly para-phenylene terephthalamide (PPTA) fibers were treated by an innovative method through the utilization of plasma jet in atmospheric pressure using a mixture of oxygen and argon as inlet gases. The effect of the volume ratio of O2/Ar and the treatment time were investigated on the interfacial properties of the fibers via SEM, AFM, ATR-FTIR analyses, and moisture sorption as well as the mechanical tests. SEM images demonstrated significant effect on the surface morphology of the fibers. In addition, ATR-FTIR spectra resulted in the creation of COOH, NH2, and OH groups on the surface of fibers. The increase in the surface functionality led to an improvement in the surface adhesion of the fibers, as observed from the pull-out tests (a maximum of 31% improvement) and moisture sorption tests (a maximum of 54% improvement). According to the results of the tensile and pull-out tests via the design expert software, the optimum condition predicted that using atmospheric pressure plasma jet employing O2/Ar volume ratio of 45.54/54.46% for 20 min results the best adhesion between the fibers and resin.
{"title":"Improving the interfacial properties of para aramid fibers by surface treatment via plasma jet method in atmospheric pressure","authors":"Mojtaba Sarafpour, I. Ebrahimi, Nadia Rahimi Tanha","doi":"10.1051/epjap/2020200277","DOIUrl":"https://doi.org/10.1051/epjap/2020200277","url":null,"abstract":"Various methods have been used by the researchers in order to improve the interfacial adhesion of para aramid fibers. In the present research, poly para-phenylene terephthalamide (PPTA) fibers were treated by an innovative method through the utilization of plasma jet in atmospheric pressure using a mixture of oxygen and argon as inlet gases. The effect of the volume ratio of O2/Ar and the treatment time were investigated on the interfacial properties of the fibers via SEM, AFM, ATR-FTIR analyses, and moisture sorption as well as the mechanical tests. SEM images demonstrated significant effect on the surface morphology of the fibers. In addition, ATR-FTIR spectra resulted in the creation of COOH, NH2, and OH groups on the surface of fibers. The increase in the surface functionality led to an improvement in the surface adhesion of the fibers, as observed from the pull-out tests (a maximum of 31% improvement) and moisture sorption tests (a maximum of 54% improvement). According to the results of the tensile and pull-out tests via the design expert software, the optimum condition predicted that using atmospheric pressure plasma jet employing O2/Ar volume ratio of 45.54/54.46% for 20 min results the best adhesion between the fibers and resin.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75640419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-08DOI: 10.1051/epjap/2020200315
L. Omari, A. Lekdadri, R. Chami, E. Hlil
The critical behavior and magnetic properties of Pr0.65Sr0.35MnO3 (symbolized here by PSMO) were studied using Monte Carlo Simulation (MCS). The thermal bath algorithm and Ising model in which exchange interactions via the third nearest neighbor were used to calculate the magnetic and magneto-caloric properties. The effects of temperature (T) and external magnetic field (h) on the magnetic behavior of PSMO were examined. The results show that the Curie temperature (TC) is close to the experimental value. The magnetic entropy shows a maximum value around the TC that increases linearly with the increase of the external field. The critical behavior of the PSMO compound was studied by analyzing the magnetization isotherms and by exploiting Arrott plots. The obtained values of the critical exponents are β = 0.336, γ = 1.121, and δ = 4.335. These values are very close to those reported for the 3D-Ising model. The variation of maximum magnetic entropy (ΔSmmax) and relative cooling power (RCP) around the Curie temperature were calculated; the obtained values of ΔSmmax and those of RCP ranging from 3.612 and 92.7 for 1T to 6.191 and 209.9 for 5T, respectively. These results are sufficiently interesting to consider the PSMO compound as a promising candidate for magnetic refrigeration.
{"title":"Critical behavior of Pr0.65Sr0.35MnO3 compound investigated by a Monte Carlo Simulation","authors":"L. Omari, A. Lekdadri, R. Chami, E. Hlil","doi":"10.1051/epjap/2020200315","DOIUrl":"https://doi.org/10.1051/epjap/2020200315","url":null,"abstract":"The critical behavior and magnetic properties of Pr0.65Sr0.35MnO3 (symbolized here by PSMO) were studied using Monte Carlo Simulation (MCS). The thermal bath algorithm and Ising model in which exchange interactions via the third nearest neighbor were used to calculate the magnetic and magneto-caloric properties. The effects of temperature (T) and external magnetic field (h) on the magnetic behavior of PSMO were examined. The results show that the Curie temperature (TC) is close to the experimental value. The magnetic entropy shows a maximum value around the TC that increases linearly with the increase of the external field. The critical behavior of the PSMO compound was studied by analyzing the magnetization isotherms and by exploiting Arrott plots. The obtained values of the critical exponents are β = 0.336, γ = 1.121, and δ = 4.335. These values are very close to those reported for the 3D-Ising model. The variation of maximum magnetic entropy (ΔSmmax) and relative cooling power (RCP) around the Curie temperature were calculated; the obtained values of ΔSmmax and those of RCP ranging from 3.612 and 92.7 for 1T to 6.191 and 209.9 for 5T, respectively. These results are sufficiently interesting to consider the PSMO compound as a promising candidate for magnetic refrigeration.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78690670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-04DOI: 10.1051/epjap/2020200222
M. Bghour, A. Labrag, H. E. Hamidi, A. Hassan, A. Taoufik
In this work, we analyze the behavior of the magnetoresistance R (H, T) of a high temperature superconductor YBa 2 Cu 3 O 7−δ thin film optimally doped. Measurements of the magnetoresistance were carried out in the mixed state for a magnetic field up to 14 T applied parallel to c − axis then parallel to ab − plane with a dc transport current of 100 and 500 nA, 0.1 and 0.3 mA perpendicular to the magnetic field direction in both cases. The obtained results show that the magnetoresistance is in a good agreement with the thermally assisted flux creep. However, the magnetoresistance in the flux flow regime cannot be described by the Barden-Stephen model which conjectures another origin of these results. In this sense, the quantum fluctuations of the order parameter is a good alternative to understanding the shape of the magnetoresistance. The comparison of the magnetoresistance of the two directions shows that [see formula in PDF] is larger than [see formula in PDF] with anisotropy factor [see formula in PDF] depending on temperature and magnetic field. The irreversibility line H irr (T) as well as H C2 (T) are determined and the first one is fitted with the phenomenological model H irr (T) = H irr (0) (1 − T/T o ) α where H irr (0), T o and α are parameters obtained from the fit. The investigation of the scaling law allows us to prove that a crossover from 3D to 2D behavior is a feature of our sample which justifies the existence of the decoherence effect.
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