Sulphur hexafluoride (SF6) gas owns remarkable properties as insulation medium and current
interrupter, which make it being widely used in gas-insulated equipment up to now. However, SF6 gas has
a drawback that gives adverse effect to the environment since it is a strong greenhouse gas. As the effort
to minimize the SF6 usage, this study was conducted to investigate the AC breakdown behavior of SF6/N2
gas mixtures with 10/90 ratio at low pressure levels (i.e. 0.11 MPa to 0.15 MPa) under non-uniform field
(i.e. R0.5-plane and R6-plane electrodes configurations). The results of the study indicate that
the breakdown voltage of SF6/N2 gas mixtures in non-uniform field increases linearly with the increase of
gas pressure and electrodes gap distance. As a function of gap distance, a higher increasing rate of
breakdown voltage values were achieved at lowest pressure of 0.11 MPa compared to other pressure
levels. In addition, it is also found that a higher breakdown voltage values was obtained under R6-plane
configuration. But, the difference in breakdown voltage values between R0.5-plane and R6-plane
configuration is less significant as the gap distance is increased. It is also observed that the field efficiency
factor of R6-plane is higher than R0.5-plane which indicates a more uniform field exists between
the electrodes.
Equations For Heavy Gases In Centrifugalsdieselpub
Centrifugal compressor performance prediction relies heavily on accurate modelling of thermodynamic properties using Equations of State (EOS); In particular, the gas compressibility factor (Z) and ratio of specific heat (k). There have been efforts to develop more generalised EOS such as GERG, but the challenge remains on identifying the best EOS fit for specific duties.
More recent EOS including AGA8 and REFPROP’s NIST EOS haven been explored in this paper, along with some earlier ones. The boundary limits of the various EOS are herein described with comparison of the results of all of these equations on various gas mixtures encountered in real applications.
The purpose of this work is to explore the more thermodynamically challenging heavy gas and mixtures. Operating points are selected to cover typical duties that are commonly encountered in LNG and offshore compression. Z and k derived from the EOS are then compared with REFPROP’s EOS as a reference and the deviations are tabulated.
More specifically, Mixed Refrigerant gases are typically used for LNG liquefaction applications while CO2 gas are common in sour gas fields, hence relevant for the intended investigation.
Discharge temperature is not calculated and compared between EOS in this paper; a reliable model for calculating polytropic exponents is open for further research.
Pressurized CF 3 I-CO Gas Mixture under Lightning Impulse and its Solid By-P...IJECEIAES
This paper describes tests results on the CF 3 I-CO gas mixtures as an alternative for SF 6 2 gas as to be used as insulating medium in high voltage applications. Pressurized CF 3 I-CO gas mixtures are subject under standard lightning impulse voltages at both positive and negative polarities. Under rod-plane configuration, the electrode gap length and gas pressure are varied accordingly. Upon completion of the laboratory tests, SEM and EDX analyses are carried out to assess the solid by-products. It was found that higher gas mixtures provide better insulation strength. In terms of weight, 50% of the solid by-product is found to be iodine.
Effect of Operating Temperatures on the Performance of a SOFC GT Hybrid Systemijtsrd
This article presents a steady state thermodynamic model of a solid oxide fuel cell gas turbine hybrid cycle which developed by using a simulation software, MATLAB®. The hybrid model integrates a zero dimensional level SOFC model with gas turbine. The hybrid system was used to study the effects of some operation parameter such as SOFC operating temperature, and current density on the specific work output, electrical efficiency, and exergy efficiency of a generic hybrid cycle. The results show that if the SOFC operating temperature, the power output, electrical efficiency, and exergy efficiency increase. The electrical efficiency of the hybrid system increase from 62 to 68 , and the exergy efficiency of the hybrid system increases from 60 to 66 when the operation temperature increases from 600°C to 750°C at a current density of 6000 A cm2. On the other hand, the system efficiency and exergy decreases with an increase in the current density. Abdulrazzak Akroot ""Effect of Operating Temperatures on the Performance of a SOFC/GT Hybrid System"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23412.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23412/effect-of-operating-temperatures-on-the-performance-of-a-sofcgt-hybrid-system/abdulrazzak-akroot
STUDY THE EFFECT OF METALLIC PARTICLE ON DIFFERENT SPACER IN A CO-AXIAL DUCT ...EditorIJAERD
Particle accelerators can be placed in two general classes, those which operate by direct time varying electric or
magnetic fields. The following discussion will relate primarily to the direct acceleration machine where the maximum
particle energy is determined by the voltage which can be insulated. In this work, it is proposed the breakdown of air gaps in
a co-axial geometry, due to the presence of metallic particle has been studied. Bare copper wire particles of different lengths
have been introduced in to a co-axial geometry and breakdown strength of air gap has been estimated. The testing high ac
voltage, positive dc voltage and negative dc voltage is carried out. The study repeated with dielectric covering to the control
conductor. When a sufficiently high electric field is applied to a gas, avalanche ionization (TOWNSEND PROCESS) occurs
which will lead to breakdown. Gas insulated systems are extensively used in air insulated system due to advantages of weight
and volume reduction, limited overall space requirements and easy maintenance. Even though case wise, GIS is very
expensive has compared to AIS, it is preferred because of better service, more reliable performance and facility of higher
operating stresses. In recent years, SF6 has been considered to green house gas and hence, all round efforts are made to
reduce emission of SF6 gas in to the atmosphere. This was successfully used in GITL (gas insulated transmission lines) and
experimental lines of few kilometers lengths are available
Equations For Heavy Gases In Centrifugalsdieselpub
Centrifugal compressor performance prediction relies heavily on accurate modelling of thermodynamic properties using Equations of State (EOS); In particular, the gas compressibility factor (Z) and ratio of specific heat (k). There have been efforts to develop more generalised EOS such as GERG, but the challenge remains on identifying the best EOS fit for specific duties.
More recent EOS including AGA8 and REFPROP’s NIST EOS haven been explored in this paper, along with some earlier ones. The boundary limits of the various EOS are herein described with comparison of the results of all of these equations on various gas mixtures encountered in real applications.
The purpose of this work is to explore the more thermodynamically challenging heavy gas and mixtures. Operating points are selected to cover typical duties that are commonly encountered in LNG and offshore compression. Z and k derived from the EOS are then compared with REFPROP’s EOS as a reference and the deviations are tabulated.
More specifically, Mixed Refrigerant gases are typically used for LNG liquefaction applications while CO2 gas are common in sour gas fields, hence relevant for the intended investigation.
Discharge temperature is not calculated and compared between EOS in this paper; a reliable model for calculating polytropic exponents is open for further research.
Pressurized CF 3 I-CO Gas Mixture under Lightning Impulse and its Solid By-P...IJECEIAES
This paper describes tests results on the CF 3 I-CO gas mixtures as an alternative for SF 6 2 gas as to be used as insulating medium in high voltage applications. Pressurized CF 3 I-CO gas mixtures are subject under standard lightning impulse voltages at both positive and negative polarities. Under rod-plane configuration, the electrode gap length and gas pressure are varied accordingly. Upon completion of the laboratory tests, SEM and EDX analyses are carried out to assess the solid by-products. It was found that higher gas mixtures provide better insulation strength. In terms of weight, 50% of the solid by-product is found to be iodine.
Effect of Operating Temperatures on the Performance of a SOFC GT Hybrid Systemijtsrd
This article presents a steady state thermodynamic model of a solid oxide fuel cell gas turbine hybrid cycle which developed by using a simulation software, MATLAB®. The hybrid model integrates a zero dimensional level SOFC model with gas turbine. The hybrid system was used to study the effects of some operation parameter such as SOFC operating temperature, and current density on the specific work output, electrical efficiency, and exergy efficiency of a generic hybrid cycle. The results show that if the SOFC operating temperature, the power output, electrical efficiency, and exergy efficiency increase. The electrical efficiency of the hybrid system increase from 62 to 68 , and the exergy efficiency of the hybrid system increases from 60 to 66 when the operation temperature increases from 600°C to 750°C at a current density of 6000 A cm2. On the other hand, the system efficiency and exergy decreases with an increase in the current density. Abdulrazzak Akroot ""Effect of Operating Temperatures on the Performance of a SOFC/GT Hybrid System"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23412.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23412/effect-of-operating-temperatures-on-the-performance-of-a-sofcgt-hybrid-system/abdulrazzak-akroot
STUDY THE EFFECT OF METALLIC PARTICLE ON DIFFERENT SPACER IN A CO-AXIAL DUCT ...EditorIJAERD
Particle accelerators can be placed in two general classes, those which operate by direct time varying electric or
magnetic fields. The following discussion will relate primarily to the direct acceleration machine where the maximum
particle energy is determined by the voltage which can be insulated. In this work, it is proposed the breakdown of air gaps in
a co-axial geometry, due to the presence of metallic particle has been studied. Bare copper wire particles of different lengths
have been introduced in to a co-axial geometry and breakdown strength of air gap has been estimated. The testing high ac
voltage, positive dc voltage and negative dc voltage is carried out. The study repeated with dielectric covering to the control
conductor. When a sufficiently high electric field is applied to a gas, avalanche ionization (TOWNSEND PROCESS) occurs
which will lead to breakdown. Gas insulated systems are extensively used in air insulated system due to advantages of weight
and volume reduction, limited overall space requirements and easy maintenance. Even though case wise, GIS is very
expensive has compared to AIS, it is preferred because of better service, more reliable performance and facility of higher
operating stresses. In recent years, SF6 has been considered to green house gas and hence, all round efforts are made to
reduce emission of SF6 gas in to the atmosphere. This was successfully used in GITL (gas insulated transmission lines) and
experimental lines of few kilometers lengths are available
Gas insulated switchgear (GIS) plays a vital role in high voltage transmission of electrical energy due to its advantages of high reliability and performance, compact in dimensions and outstanding compatibility with the environment. It uses sulphur hexafluoride gas as its insulant and coolant because of its high dielectric strength and excellent arc quenching ability. Gas insulated switchgear in operation suffers the challenge of its insulation decomposition and eventually failure due to the activities of partial discharge that arouses from defects. This failure is catastrophic and it will lead to entire power out stage that will affect all categories of human activities, so there is a need for Gas insulated switchgear condition monitoring and diagnoses in order to carry out preventive maintenance. This paper reviews diagnostic techniques and methods for Gas insulated switchgear insulation degradation caused by partial discharge for the purpose of carrying out preventive maintenance to avert its failure.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
PyTeCK: A Python-based automatic testing package for chemical kinetic modelsOregon State University
Combustion simulations require detailed chemical kinetic models to predict fuel oxidation, heat release, and pollutant emissions. These models are typically validated using qualitative rather than quantitative comparisons with limited sets of experimental data. This work introduces PyTeCK, an open-source Python-based package for automatic testing of chemical kinetic models. Given a model of interest, PyTeCK automatically parses experimental datasets encoded in a YAML format, validates the self-consistency of each dataset, and performs simulations for each experimental datapoint. It then reports a quantitative metric of the model's performance, based on the discrepancy between experimental and simulated values and weighted by experimental variance. The initial version of PyTeCK supports shock tube and rapid compression machine experiments that measure autoignition delay. PyTeCK relies on several packages in the SciPy stack and greater scientific Python ecosystem. In addition to providing an easy-to-use, automated tool for evaluating chemical kinetic model performance, a secondary objective of PyTeCK is to encourage greater openness and reproducibility in combustion research.
The effect of reduced pressure acetylene plasma treatment on physical charact...inventy
The capacitors are increasingly being used as energy storage devicesin various power systems. The scientists of the world are tryingto maximize the electrical capacity of the supercapacitors. To achieve this purpose, numerous method sare used: the surface activation of electrodes, the surface etching using the electronbeam, the electrode etching with variousgasplasma, etc. The purpose of this work is toresearch how the properties of carbon electrodes depend on the plasma parameters at whichtheywere formed. The largest surface area ofcarbonelectrodeof47.25m2 /gis obtainedat 15 ofAr/C2H2gasratio. Meanwhile, theSEMimages show that the disruption of structures with low bond energies and the formation of new onesare taking place when the carbon electrodes are etched at acetylene plasma and placed on carbon electrode. The measurements of capacitance showthat capacitors with affectedelectrodes have about10-15% highercapacity than those not treated with acetyleneplasma.
The Performance of an Integrated Transformer in a DC/DC ConverterTELKOMNIKA JOURNAL
The separation between the low-voltage part and high-voltage part of the converter is formed by a
transformer that transfers power while jamming the DC ring. The resonant mode power oscillator is utilized
to allow elevated competence power transfer. The on-chip transformer is probable to have elevated value
inductance, elevated quality factors and elevated coupling coefficient to decrease the loss in the
oscillation. The performance of a transformer is extremely dependent on the structure, topology and other
essential structures that create it compatible with the integrated circuits IC process such as patterned
ground shield (PGS). Different types of transformers are modeled and simulated in MATLAB; the
performances are compared to select the optimum design. The on-chip transformer model is simulated
and the Results of MATLAB simulation are exposed, showing an excellent agreement in radio frequency
RF.
An autoignition performance comparison of chemical kinetics models for n-heptaneOregon State University
Surrogate models of gasoline typically include the primarily reference fuel (PRF) n-heptane. The chemical kinetics literature contains many models for n-heptane, but no comprehensive survey or performance validation for these models exist. This paper objectively compares the performance of various chemical kinetics models for n-heptane for autoignition, using experimental data from a variety of sources. In doing so, recommendations for choosing appropriate models are made and areas of improvement identified. As a secondary goal, this work also collected and standardized a wide range of shock tube and rapid compression machine autoignition data for this neat fuel. This study represents the first step of a comprehensive study of models for n-heptane, isooctane, toluene, and ethanol alone and in binary, ternary, and quaternary mixtures.
Threshold Voltage Roll-off by Structural Parameters for Sub-10 nm Asymmetric ...TELKOMNIKA JOURNAL
This study is to analyze threshold voltage roll-off according to structural parameters of sub-10 nm
asymmetric double gate MOSFET. In case of sub-10nm channel length, because of short channel effects
resulting from the rapid increase of tunneling current, even asymmetric double gate (DG) MOSFET, which
has been developed for reducing short channel effects, will increase threshold voltage roll-off, and this is
an obstacle against the miniaturization of asymmetric DGMOSFET. Especially, since asymmetric
DGMOSFET can be produced differently in top and bottom oxide thickness, top/bottom oxide thickness will
affect the threshold voltage roll-off. To analyze this, thermal emission current and tunneling current model
have been calculated, and threshold voltage roll-off in accordance with the reduction of channel length has
been analyzed by using channel thickness and top/bottom oxide thickness as parameters. As a result, it is
found that, in short channel asymmetric double gate MOSFET, threshold voltage roll-off is changed greatly
according to top/bottom gate oxide thickness, and that threshold voltage roll-off, in particular, is generated
more greatly according to silicon thickness. In addition, it is found that top and bottom oxide thickness have
a relation of inverse proportion mutually for maintaining identical threshold voltage.
The Futures of the Physic-Chemical and Thermoelectric Properties of the InTe-...theijes
By the methods of the physic-chemical analysis as well the measurements of microhadness and picknomentric density the semiconducting system InTe-Cu2ZnSnS4 has been investigated and its state diagram has been plotted. Guazibinarity of the system with restricted homogeneous fields has established on the basis of both initial components. The boundaries of solid solutions at 300K reach on side of InTe ~ 2mol% and on side of Cu2ZnSnS4 ~ 13mol%. The coordinates of the system eutectic correspond to the composition ~23mol% Cu2ZnSnS4 and temperature ~813K. A study of thermoelectric and galvanomagnetic parameters of solid solutions (InTe)1-x(Cu2ZnSnS4)x showed dispersion of electrons from the ionized admixture at low temperatures, and at higher temperatures from thermal vibrations of crystalline lattice. Heat transfer takes place according to one-phonon mechanism. The alloy of solid solution (InTe)0,98(Cu2ZnSnS4)0,02 possesses a high value of thermoelectric efficiency.
Amazon products reviews classification based on machine learning, deep learni...TELKOMNIKA JOURNAL
In recent times, the trend of online shopping through e-commerce stores and websites has grown to a huge extent. Whenever a product is purchased on an e-commerce platform, people leave their reviews about the product. These reviews are very helpful for the store owners and the product’s manufacturers for the betterment of their work process as well as product quality. An automated system is proposed in this work that operates on two datasets D1 and D2 obtained from Amazon. After certain preprocessing steps, N-gram and word embedding-based features are extracted using term frequency-inverse document frequency (TF-IDF), bag of words (BoW) and global vectors (GloVe), and Word2vec, respectively. Four machine learning (ML) models support vector machines (SVM), logistic regression (RF), logistic regression (LR), multinomial Naïve Bayes (MNB), two deep learning (DL) models convolutional neural network (CNN), long-short term memory (LSTM), and standalone bidirectional encoder representations (BERT) are used to classify reviews as either positive or negative. The results obtained by the standard ML, DL models and BERT are evaluated using certain performance evaluation measures. BERT turns out to be the best-performing model in the case of D1 with an accuracy of 90% on features derived by word embedding models while the CNN provides the best accuracy of 97% upon word embedding features in the case of D2. The proposed model shows better overall performance on D2 as compared to D1.
Design, simulation, and analysis of microstrip patch antenna for wireless app...TELKOMNIKA JOURNAL
In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication.
More Related Content
Similar to AC breakdown behavior of SF6/N2 gas mixtures under non-uniform field electrode configurations
Gas insulated switchgear (GIS) plays a vital role in high voltage transmission of electrical energy due to its advantages of high reliability and performance, compact in dimensions and outstanding compatibility with the environment. It uses sulphur hexafluoride gas as its insulant and coolant because of its high dielectric strength and excellent arc quenching ability. Gas insulated switchgear in operation suffers the challenge of its insulation decomposition and eventually failure due to the activities of partial discharge that arouses from defects. This failure is catastrophic and it will lead to entire power out stage that will affect all categories of human activities, so there is a need for Gas insulated switchgear condition monitoring and diagnoses in order to carry out preventive maintenance. This paper reviews diagnostic techniques and methods for Gas insulated switchgear insulation degradation caused by partial discharge for the purpose of carrying out preventive maintenance to avert its failure.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
PyTeCK: A Python-based automatic testing package for chemical kinetic modelsOregon State University
Combustion simulations require detailed chemical kinetic models to predict fuel oxidation, heat release, and pollutant emissions. These models are typically validated using qualitative rather than quantitative comparisons with limited sets of experimental data. This work introduces PyTeCK, an open-source Python-based package for automatic testing of chemical kinetic models. Given a model of interest, PyTeCK automatically parses experimental datasets encoded in a YAML format, validates the self-consistency of each dataset, and performs simulations for each experimental datapoint. It then reports a quantitative metric of the model's performance, based on the discrepancy between experimental and simulated values and weighted by experimental variance. The initial version of PyTeCK supports shock tube and rapid compression machine experiments that measure autoignition delay. PyTeCK relies on several packages in the SciPy stack and greater scientific Python ecosystem. In addition to providing an easy-to-use, automated tool for evaluating chemical kinetic model performance, a secondary objective of PyTeCK is to encourage greater openness and reproducibility in combustion research.
The effect of reduced pressure acetylene plasma treatment on physical charact...inventy
The capacitors are increasingly being used as energy storage devicesin various power systems. The scientists of the world are tryingto maximize the electrical capacity of the supercapacitors. To achieve this purpose, numerous method sare used: the surface activation of electrodes, the surface etching using the electronbeam, the electrode etching with variousgasplasma, etc. The purpose of this work is toresearch how the properties of carbon electrodes depend on the plasma parameters at whichtheywere formed. The largest surface area ofcarbonelectrodeof47.25m2 /gis obtainedat 15 ofAr/C2H2gasratio. Meanwhile, theSEMimages show that the disruption of structures with low bond energies and the formation of new onesare taking place when the carbon electrodes are etched at acetylene plasma and placed on carbon electrode. The measurements of capacitance showthat capacitors with affectedelectrodes have about10-15% highercapacity than those not treated with acetyleneplasma.
The Performance of an Integrated Transformer in a DC/DC ConverterTELKOMNIKA JOURNAL
The separation between the low-voltage part and high-voltage part of the converter is formed by a
transformer that transfers power while jamming the DC ring. The resonant mode power oscillator is utilized
to allow elevated competence power transfer. The on-chip transformer is probable to have elevated value
inductance, elevated quality factors and elevated coupling coefficient to decrease the loss in the
oscillation. The performance of a transformer is extremely dependent on the structure, topology and other
essential structures that create it compatible with the integrated circuits IC process such as patterned
ground shield (PGS). Different types of transformers are modeled and simulated in MATLAB; the
performances are compared to select the optimum design. The on-chip transformer model is simulated
and the Results of MATLAB simulation are exposed, showing an excellent agreement in radio frequency
RF.
An autoignition performance comparison of chemical kinetics models for n-heptaneOregon State University
Surrogate models of gasoline typically include the primarily reference fuel (PRF) n-heptane. The chemical kinetics literature contains many models for n-heptane, but no comprehensive survey or performance validation for these models exist. This paper objectively compares the performance of various chemical kinetics models for n-heptane for autoignition, using experimental data from a variety of sources. In doing so, recommendations for choosing appropriate models are made and areas of improvement identified. As a secondary goal, this work also collected and standardized a wide range of shock tube and rapid compression machine autoignition data for this neat fuel. This study represents the first step of a comprehensive study of models for n-heptane, isooctane, toluene, and ethanol alone and in binary, ternary, and quaternary mixtures.
Threshold Voltage Roll-off by Structural Parameters for Sub-10 nm Asymmetric ...TELKOMNIKA JOURNAL
This study is to analyze threshold voltage roll-off according to structural parameters of sub-10 nm
asymmetric double gate MOSFET. In case of sub-10nm channel length, because of short channel effects
resulting from the rapid increase of tunneling current, even asymmetric double gate (DG) MOSFET, which
has been developed for reducing short channel effects, will increase threshold voltage roll-off, and this is
an obstacle against the miniaturization of asymmetric DGMOSFET. Especially, since asymmetric
DGMOSFET can be produced differently in top and bottom oxide thickness, top/bottom oxide thickness will
affect the threshold voltage roll-off. To analyze this, thermal emission current and tunneling current model
have been calculated, and threshold voltage roll-off in accordance with the reduction of channel length has
been analyzed by using channel thickness and top/bottom oxide thickness as parameters. As a result, it is
found that, in short channel asymmetric double gate MOSFET, threshold voltage roll-off is changed greatly
according to top/bottom gate oxide thickness, and that threshold voltage roll-off, in particular, is generated
more greatly according to silicon thickness. In addition, it is found that top and bottom oxide thickness have
a relation of inverse proportion mutually for maintaining identical threshold voltage.
The Futures of the Physic-Chemical and Thermoelectric Properties of the InTe-...theijes
By the methods of the physic-chemical analysis as well the measurements of microhadness and picknomentric density the semiconducting system InTe-Cu2ZnSnS4 has been investigated and its state diagram has been plotted. Guazibinarity of the system with restricted homogeneous fields has established on the basis of both initial components. The boundaries of solid solutions at 300K reach on side of InTe ~ 2mol% and on side of Cu2ZnSnS4 ~ 13mol%. The coordinates of the system eutectic correspond to the composition ~23mol% Cu2ZnSnS4 and temperature ~813K. A study of thermoelectric and galvanomagnetic parameters of solid solutions (InTe)1-x(Cu2ZnSnS4)x showed dispersion of electrons from the ionized admixture at low temperatures, and at higher temperatures from thermal vibrations of crystalline lattice. Heat transfer takes place according to one-phonon mechanism. The alloy of solid solution (InTe)0,98(Cu2ZnSnS4)0,02 possesses a high value of thermoelectric efficiency.
Amazon products reviews classification based on machine learning, deep learni...TELKOMNIKA JOURNAL
In recent times, the trend of online shopping through e-commerce stores and websites has grown to a huge extent. Whenever a product is purchased on an e-commerce platform, people leave their reviews about the product. These reviews are very helpful for the store owners and the product’s manufacturers for the betterment of their work process as well as product quality. An automated system is proposed in this work that operates on two datasets D1 and D2 obtained from Amazon. After certain preprocessing steps, N-gram and word embedding-based features are extracted using term frequency-inverse document frequency (TF-IDF), bag of words (BoW) and global vectors (GloVe), and Word2vec, respectively. Four machine learning (ML) models support vector machines (SVM), logistic regression (RF), logistic regression (LR), multinomial Naïve Bayes (MNB), two deep learning (DL) models convolutional neural network (CNN), long-short term memory (LSTM), and standalone bidirectional encoder representations (BERT) are used to classify reviews as either positive or negative. The results obtained by the standard ML, DL models and BERT are evaluated using certain performance evaluation measures. BERT turns out to be the best-performing model in the case of D1 with an accuracy of 90% on features derived by word embedding models while the CNN provides the best accuracy of 97% upon word embedding features in the case of D2. The proposed model shows better overall performance on D2 as compared to D1.
Design, simulation, and analysis of microstrip patch antenna for wireless app...TELKOMNIKA JOURNAL
In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication.
Design and simulation an optimal enhanced PI controller for congestion avoida...TELKOMNIKA JOURNAL
In this paper, snake optimization algorithm (SOA) is used to find the optimal gains of an enhanced controller for controlling congestion problem in computer networks. M-file and Simulink platform is adopted to evaluate the response of the active queue management (AQM) system, a comparison with two classical controllers is done, all tuned gains of controllers are obtained using SOA method and the fitness function chose to monitor the system performance is the integral time absolute error (ITAE). Transient analysis and robust analysis is used to show the proposed controller performance, two robustness tests are applied to the AQM system, one is done by varying the size of queue value in different period and the other test is done by changing the number of transmission control protocol (TCP) sessions with a value of ± 20% from its original value. The simulation results reflect a stable and robust behavior and best performance is appeared clearly to achieve the desired queue size without any noise or any transmission problems.
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Vehicular ad-hoc networks (VANETs) are wireless-equipped vehicles that form networks along the road. The security of this network has been a major challenge. The identity-based cryptosystem (IBC) previously used to secure the networks suffers from membership authentication security features. This paper focuses on improving the detection of intruders in VANETs with a modified identity-based cryptosystem (MIBC). The MIBC is developed using a non-singular elliptic curve with Lagrange interpolation. The public key of vehicles and roadside units on the network are derived from number plates and location identification numbers, respectively. Pseudo-identities are used to mask the real identity of users to preserve their privacy. The membership authentication mechanism ensures that only valid and authenticated members of the network are allowed to join the network. The performance of the MIBC is evaluated using intrusion detection ratio (IDR) and computation time (CT) and then validated with the existing IBC. The result obtained shows that the MIBC recorded an IDR of 99.3% against 94.3% obtained for the existing identity-based cryptosystem (EIBC) for 140 unregistered vehicles attempting to intrude on the network. The MIBC shows lower CT values of 1.17 ms against 1.70 ms for EIBC. The MIBC can be used to improve the security of VANETs.
Conceptual model of internet banking adoption with perceived risk and trust f...TELKOMNIKA JOURNAL
Understanding the primary factors of internet banking (IB) acceptance is critical for both banks and users; nevertheless, our knowledge of the role of users’ perceived risk and trust in IB adoption is limited. As a result, we develop a conceptual model by incorporating perceived risk and trust into the technology acceptance model (TAM) theory toward the IB. The proper research emphasized that the most essential component in explaining IB adoption behavior is behavioral intention to use IB adoption. TAM is helpful for figuring out how elements that affect IB adoption are connected to one another. According to previous literature on IB and the use of such technology in Iraq, one has to choose a theoretical foundation that may justify the acceptance of IB from the customer’s perspective. The conceptual model was therefore constructed using the TAM as a foundation. Furthermore, perceived risk and trust were added to the TAM dimensions as external factors. The key objective of this work was to extend the TAM to construct a conceptual model for IB adoption and to get sufficient theoretical support from the existing literature for the essential elements and their relationships in order to unearth new insights about factors responsible for IB adoption.
Efficient combined fuzzy logic and LMS algorithm for smart antennaTELKOMNIKA JOURNAL
The smart antennas are broadly used in wireless communication. The least mean square (LMS) algorithm is a procedure that is concerned in controlling the smart antenna pattern to accommodate specified requirements such as steering the beam toward the desired signal, in addition to placing the deep nulls in the direction of unwanted signals. The conventional LMS (C-LMS) has some drawbacks like slow convergence speed besides high steady state fluctuation error. To overcome these shortcomings, the present paper adopts an adaptive fuzzy control step size least mean square (FC-LMS) algorithm to adjust its step size. Computer simulation outcomes illustrate that the given model has fast convergence rate as well as low mean square error steady state.
Design and implementation of a LoRa-based system for warning of forest fireTELKOMNIKA JOURNAL
This paper presents the design and implementation of a forest fire monitoring and warning system based on long range (LoRa) technology, a novel ultra-low power consumption and long-range wireless communication technology for remote sensing applications. The proposed system includes a wireless sensor network that records environmental parameters such as temperature, humidity, wind speed, and carbon dioxide (CO2) concentration in the air, as well as taking infrared photos.The data collected at each sensor node will be transmitted to the gateway via LoRa wireless transmission. Data will be collected, processed, and uploaded to a cloud database at the gateway. An Android smartphone application that allows anyone to easily view the recorded data has been developed. When a fire is detected, the system will sound a siren and send a warning message to the responsible personnel, instructing them to take appropriate action. Experiments in Tram Chim Park, Vietnam, have been conducted to verify and evaluate the operation of the system.
Wavelet-based sensing technique in cognitive radio networkTELKOMNIKA JOURNAL
Cognitive radio is a smart radio that can change its transmitter parameter based on interaction with the environment in which it operates. The demand for frequency spectrum is growing due to a big data issue as many Internet of Things (IoT) devices are in the network. Based on previous research, most frequency spectrum was used, but some spectrums were not used, called spectrum hole. Energy detection is one of the spectrum sensing methods that has been frequently used since it is easy to use and does not require license users to have any prior signal understanding. But this technique is incapable of detecting at low signal-to-noise ratio (SNR) levels. Therefore, the wavelet-based sensing is proposed to overcome this issue and detect spectrum holes. The main objective of this work is to evaluate the performance of wavelet-based sensing and compare it with the energy detection technique. The findings show that the percentage of detection in wavelet-based sensing is 83% higher than energy detection performance. This result indicates that the wavelet-based sensing has higher precision in detection and the interference towards primary user can be decreased.
A novel compact dual-band bandstop filter with enhanced rejection bandsTELKOMNIKA JOURNAL
In this paper, we present the design of a new wide dual-band bandstop filter (DBBSF) using nonuniform transmission lines. The method used to design this filter is to replace conventional uniform transmission lines with nonuniform lines governed by a truncated Fourier series. Based on how impedances are profiled in the proposed DBBSF structure, the fractional bandwidths of the two 10 dB-down rejection bands are widened to 39.72% and 52.63%, respectively, and the physical size has been reduced compared to that of the filter with the uniform transmission lines. The results of the electromagnetic (EM) simulation support the obtained analytical response and show an improved frequency behavior.
Deep learning approach to DDoS attack with imbalanced data at the application...TELKOMNIKA JOURNAL
A distributed denial of service (DDoS) attack is where one or more computers attack or target a server computer, by flooding internet traffic to the server. As a result, the server cannot be accessed by legitimate users. A result of this attack causes enormous losses for a company because it can reduce the level of user trust, and reduce the company’s reputation to lose customers due to downtime. One of the services at the application layer that can be accessed by users is a web-based lightweight directory access protocol (LDAP) service that can provide safe and easy services to access directory applications. We used a deep learning approach to detect DDoS attacks on the CICDDoS 2019 dataset on a complex computer network at the application layer to get fast and accurate results for dealing with unbalanced data. Based on the results obtained, it is observed that DDoS attack detection using a deep learning approach on imbalanced data performs better when implemented using synthetic minority oversampling technique (SMOTE) method for binary classes. On the other hand, the proposed deep learning approach performs better for detecting DDoS attacks in multiclass when implemented using the adaptive synthetic (ADASYN) method.
The appearance of uncertainties and disturbances often effects the characteristics of either linear or nonlinear systems. Plus, the stabilization process may be deteriorated thus incurring a catastrophic effect to the system performance. As such, this manuscript addresses the concept of matching condition for the systems that are suffering from miss-match uncertainties and exogeneous disturbances. The perturbation towards the system at hand is assumed to be known and unbounded. To reach this outcome, uncertainties and their classifications are reviewed thoroughly. The structural matching condition is proposed and tabulated in the proposition 1. Two types of mathematical expressions are presented to distinguish the system with matched uncertainty and the system with miss-matched uncertainty. Lastly, two-dimensional numerical expressions are provided to practice the proposed proposition. The outcome shows that matching condition has the ability to change the system to a design-friendly model for asymptotic stabilization.
Implementation of FinFET technology based low power 4×4 Wallace tree multipli...TELKOMNIKA JOURNAL
Many systems, including digital signal processors, finite impulse response (FIR) filters, application-specific integrated circuits, and microprocessors, use multipliers. The demand for low power multipliers is gradually rising day by day in the current technological trend. In this study, we describe a 4×4 Wallace multiplier based on a carry select adder (CSA) that uses less power and has a better power delay product than existing multipliers. HSPICE tool at 16 nm technology is used to simulate the results. In comparison to the traditional CSA-based multiplier, which has a power consumption of 1.7 µW and power delay product (PDP) of 57.3 fJ, the results demonstrate that the Wallace multiplier design employing CSA with first zero finding logic (FZF) logic has the lowest power consumption of 1.4 µW and PDP of 27.5 fJ.
Evaluation of the weighted-overlap add model with massive MIMO in a 5G systemTELKOMNIKA JOURNAL
The flaw in 5G orthogonal frequency division multiplexing (OFDM) becomes apparent in high-speed situations. Because the doppler effect causes frequency shifts, the orthogonality of OFDM subcarriers is broken, lowering both their bit error rate (BER) and throughput output. As part of this research, we use a novel design that combines massive multiple input multiple output (MIMO) and weighted overlap and add (WOLA) to improve the performance of 5G systems. To determine which design is superior, throughput and BER are calculated for both the proposed design and OFDM. The results of the improved system show a massive improvement in performance ver the conventional system and significant improvements with massive MIMO, including the best throughput and BER. When compared to conventional systems, the improved system has a throughput that is around 22% higher and the best performance in terms of BER, but it still has around 25% less error than OFDM.
Reflector antenna design in different frequencies using frequency selective s...TELKOMNIKA JOURNAL
In this study, it is aimed to obtain two different asymmetric radiation patterns obtained from antennas in the shape of the cross-section of a parabolic reflector (fan blade type antennas) and antennas with cosecant-square radiation characteristics at two different frequencies from a single antenna. For this purpose, firstly, a fan blade type antenna design will be made, and then the reflective surface of this antenna will be completed to the shape of the reflective surface of the antenna with the cosecant-square radiation characteristic with the frequency selective surface designed to provide the characteristics suitable for the purpose. The frequency selective surface designed and it provides the perfect transmission as possible at 4 GHz operating frequency, while it will act as a band-quenching filter for electromagnetic waves at 5 GHz operating frequency and will be a reflective surface. Thanks to this frequency selective surface to be used as a reflective surface in the antenna, a fan blade type radiation characteristic at 4 GHz operating frequency will be obtained, while a cosecant-square radiation characteristic at 5 GHz operating frequency will be obtained.
Reagentless iron detection in water based on unclad fiber optical sensorTELKOMNIKA JOURNAL
A simple and low-cost fiber based optical sensor for iron detection is demonstrated in this paper. The sensor head consist of an unclad optical fiber with the unclad length of 1 cm and it has a straight structure. Results obtained shows a linear relationship between the output light intensity and iron concentration, illustrating the functionality of this iron optical sensor. Based on the experimental results, the sensitivity and linearity are achieved at 0.0328/ppm and 0.9824 respectively at the wavelength of 690 nm. With the same wavelength, other performance parameters are also studied. Resolution and limit of detection (LOD) are found to be 0.3049 ppm and 0.0755 ppm correspondingly. This iron sensor is advantageous in that it does not require any reagent for detection, enabling it to be simpler and cost-effective in the implementation of the iron sensing.
Impact of CuS counter electrode calcination temperature on quantum dot sensit...TELKOMNIKA JOURNAL
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
A progressive learning for structural tolerance online sequential extreme lea...TELKOMNIKA JOURNAL
This article discusses the progressive learning for structural tolerance online sequential extreme learning machine (PSTOS-ELM). PSTOS-ELM can save robust accuracy while updating the new data and the new class data on the online training situation. The robustness accuracy arises from using the householder block exact QR decomposition recursive least squares (HBQRD-RLS) of the PSTOS-ELM. This method is suitable for applications that have data streaming and often have new class data. Our experiment compares the PSTOS-ELM accuracy and accuracy robustness while data is updating with the batch-extreme learning machine (ELM) and structural tolerance online sequential extreme learning machine (STOS-ELM) that both must retrain the data in a new class data case. The experimental results show that PSTOS-ELM has accuracy and robustness comparable to ELM and STOS-ELM while also can update new class data immediately.
Electroencephalography-based brain-computer interface using neural networksTELKOMNIKA JOURNAL
This study aimed to develop a brain-computer interface that can control an electric wheelchair using electroencephalography (EEG) signals. First, we used the Mind Wave Mobile 2 device to capture raw EEG signals from the surface of the scalp. The signals were transformed into the frequency domain using fast Fourier transform (FFT) and filtered to monitor changes in attention and relaxation. Next, we performed time and frequency domain analyses to identify features for five eye gestures: opened, closed, blink per second, double blink, and lookup. The base state was the opened-eyes gesture, and we compared the features of the remaining four action gestures to the base state to identify potential gestures. We then built a multilayer neural network to classify these features into five signals that control the wheelchair’s movement. Finally, we designed an experimental wheelchair system to test the effectiveness of the proposed approach. The results demonstrate that the EEG classification was highly accurate and computationally efficient. Moreover, the average performance of the brain-controlled wheelchair system was over 75% across different individuals, which suggests the feasibility of this approach.
Adaptive segmentation algorithm based on level set model in medical imagingTELKOMNIKA JOURNAL
For image segmentation, level set models are frequently employed. It offer best solution to overcome the main limitations of deformable parametric models. However, the challenge when applying those models in medical images stills deal with removing blurs in image edges which directly affects the edge indicator function, leads to not adaptively segmenting images and causes a wrong analysis of pathologies wich prevents to conclude a correct diagnosis. To overcome such issues, an effective process is suggested by simultaneously modelling and solving systems’ two-dimensional partial differential equations (PDE). The first PDE equation allows restoration using Euler’s equation similar to an anisotropic smoothing based on a regularized Perona and Malik filter that eliminates noise while preserving edge information in accordance with detected contours in the second equation that segments the image based on the first equation solutions. This approach allows developing a new algorithm which overcome the studied model drawbacks. Results of the proposed method give clear segments that can be applied to any application. Experiments on many medical images in particular blurry images with high information losses, demonstrate that the developed approach produces superior segmentation results in terms of quantity and quality compared to other models already presented in previeous works.
Automatic channel selection using shuffled frog leaping algorithm for EEG bas...TELKOMNIKA JOURNAL
Drug addiction is a complex neurobiological disorder that necessitates comprehensive treatment of both the body and mind. It is categorized as a brain disorder due to its impact on the brain. Various methods such as electroencephalography (EEG), functional magnetic resonance imaging (FMRI), and magnetoencephalography (MEG) can capture brain activities and structures. EEG signals provide valuable insights into neurological disorders, including drug addiction. Accurate classification of drug addiction from EEG signals relies on appropriate features and channel selection. Choosing the right EEG channels is essential to reduce computational costs and mitigate the risk of overfitting associated with using all available channels. To address the challenge of optimal channel selection in addiction detection from EEG signals, this work employs the shuffled frog leaping algorithm (SFLA). SFLA facilitates the selection of appropriate channels, leading to improved accuracy. Wavelet features extracted from the selected input channel signals are then analyzed using various machine learning classifiers to detect addiction. Experimental results indicate that after selecting features from the appropriate channels, classification accuracy significantly increased across all classifiers. Particularly, the multi-layer perceptron (MLP) classifier combined with SFLA demonstrated a remarkable accuracy improvement of 15.78% while reducing time complexity.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Online aptitude test management system project report.pdfKamal Acharya
The purpose of on-line aptitude test system is to take online test in an efficient manner and no time wasting for checking the paper. The main objective of on-line aptitude test system is to efficiently evaluate the candidate thoroughly through a fully automated system that not only saves lot of time but also gives fast results. For students they give papers according to their convenience and time and there is no need of using extra thing like paper, pen etc. This can be used in educational institutions as well as in corporate world. Can be used anywhere any time as it is a web based application (user Location doesn’t matter). No restriction that examiner has to be present when the candidate takes the test.
Every time when lecturers/professors need to conduct examinations they have to sit down think about the questions and then create a whole new set of questions for each and every exam. In some cases the professor may want to give an open book online exam that is the student can take the exam any time anywhere, but the student might have to answer the questions in a limited time period. The professor may want to change the sequence of questions for every student. The problem that a student has is whenever a date for the exam is declared the student has to take it and there is no way he can take it at some other time. This project will create an interface for the examiner to create and store questions in a repository. It will also create an interface for the student to take examinations at his convenience and the questions and/or exams may be timed. Thereby creating an application which can be used by examiners and examinee’s simultaneously.
Examination System is very useful for Teachers/Professors. As in the teaching profession, you are responsible for writing question papers. In the conventional method, you write the question paper on paper, keep question papers separate from answers and all this information you have to keep in a locker to avoid unauthorized access. Using the Examination System you can create a question paper and everything will be written to a single exam file in encrypted format. You can set the General and Administrator password to avoid unauthorized access to your question paper. Every time you start the examination, the program shuffles all the questions and selects them randomly from the database, which reduces the chances of memorizing the questions.
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
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The focus of interest is given on the small pressure range (i.e. 0.11 MPa to 0.15 MPa) which
normally used for ring main unit (RMU) switchgear application.
2. Research Method
2.1. Experimental Setup
In order to investigate the breakdown behavior of SF6/N2 gas mixtures, a series of AC
breakdown test was conducted inside a custom made pressure vessel [22], where
the experimental setup is shown in Figure 1. The pressure vessel was designed with a volume
capacity of 205 liters and the maximum withstand voltage is 70 kV/min. In this study, the test
procedures of AC breakdown voltage test are complied with BS EN 60060-1 standard [23].
For the purpose of statistical analysis, a minimum of 30 consecutives breakdown data was
taken for each SF6/N2 gas mixtures tests. Throughout this study, the AC breakdown behavior
SF6/N2 gas mixtures was examined under non-uniform field for various gas pressure and
electrode gap distance. The SF6/N2 gas mixture ratio was fixed to 10/90, while the total gas
pressure is varied at small range (i.e. 0.11 MPa to 0.15 MPa with 0.01 MPa interval). To
represents different non-uniform field condition, two types of electrodes configurations were
used; R0.5-plane and R6-plane configurations (refer to Figure 1). The high voltage electrodes of
R0.5 and R6 have a tip radius of 0.5 mm and 6 mm, respectively, while the ground electrode of
plane has a 50 mm radius. The gap distances between the high voltage and ground electrode is
varied from 5 mm to 25 mm.
2.2. Experimental Method
The SF6/N2 gas mixture is prepared according to Dalton’s Law as shown in (1).
The equation describes that the total pressure of the gas mixture is equal to the sum of partial
pressures of its individual (pure) gases [24]. For instance, at 0.10 MPa and SF6/N2 (10/90) gas
mixtures ratio, the partial pressure of SF6 and N2 is 0.01 MPa and 0.09 MPa, correspondingly. In
this case, the pressure vessel was filled in with the low gas content of SF6 which is 10%,
followed by the other 90% of N2 gas. The SF6/N2 gas mixture is then left for 24 hours to ensure
a uniform gas mixture before conducting the AC breakdown voltage test [13, 14].
𝑃𝑆𝐹6/𝑁2
= 𝑃𝑆𝐹6
+ 𝑃 𝑁2
(1)
Figure 1. Experimental setup for AC voltage generations
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AC breakdown behavior of SF6/N2 gas mixtures under non-uniform field... (H. Zainuddin)
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3. Results and Analysis
3.1. AC Breakdown Voltage Distribution of SF6/N2 Gas Mixtures
Figure 2 shows the 3D visualization plot for mean AC breakdown voltage, Ua of SF6/N2
gas mixtures as a function of gas pressure (i.e. 0.11 MPa to 0.15 MPa) and electrodes gap
distances (i.e. 5 mm to 25 mm) under R0.5-plane and R6-plane configuration. By referring to
Figure 2, the distributions of Ua values at SF6/N2 (10/90) gas mixtures ratio is presented as
the probability of breakdown event that occur at certain voltage range. According to Figure 2,
the Ua values of SF6/N2 gas mixtures under R0.5-plane and R6-plane configurations are
classified into four voltage ranges (in kV); 10-20, 20-30, 30-40 and 40-50. It is noticed that both
electrode configurations have the lowest Ua values at 10-20 kV, while the highest Ua values are
at 40-50 kV. However, the distribution percentages of Ua values under both electrode
configurations seem different at all voltage ranges. For instance, the probability of the lowest
and the highest Ua values under R0.5-plane configuration are 20% and 8%, respectively. But,
as R6-plane configuration is used, the probability of the lowest Ua values decreases from 20%
to 4%, whereas the probability of the highest Ua values increases from 8% to 16%. This shows
that the use of R6-plane configuration has caused more breakdown event occur at high voltage
range (i.e. at 40-50 kV), which mainly due to its high electric field uniformity compared to
R0.5-plane configuration.
Figure 2. 3D visualization plot for mean AC breakdown voltage of SF6/N2 (10/90) gas mixtures
under different electrode configuration
3.2. Effect of Gap Distance to the AC Breakdown Voltage
As depicted in Figure 3, further analysis has been done on the effect of electrodes gap
distance to the Ua values of SF6/N2 gas mixtures at various gas pressures under different
electrode configurations; R0.5-plane and R6 plane. It is found that the Ua values increase
linearly as the gap distance between the electrodes are increased from 5 mm to 25 mm. For
R0.5-plane configuration, the Ua values of SF6/N2 (10/90) mixtures at 0.11 MPa and 0.15 MPa
increase by 134.7% and 99.0%, respectively, as the electrodes gap distances is varied from
5 mm to 25 mm. At the same pressure level, the increasing rates of Ua values for R6-plane
configuration are 78.7% and 70.3%, respectively. It can be seen that for both electrode
configurations, the increasing rate of Ua values decrease as the pressure are increased from
0.11 MPa to 0.15 MPa. That is to say, the effect of electrodes gap distance in affecting
the Ua values is more significant at 0.11 MPa. Meanwhile, as a function of pressure, it is
observed that there is not much difference in Ua values under R0.5-plane configuration as
the pressure is increased from 0.11 MPa to 0.15 MPa, especially at 25 mm electrodes gap
distance, compared to R6-plane configurations.
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Figure 3. Mean AC breakdown voltage of SF6/N2 gas mixtures as a function of gap distance
under different electrode configuration
3.3. Effect of Gas Pressure to the AC Breakdown Voltage
Figure 4 shows the Ua values of SF6/N2 gas mixtures as a function of pressure for two
different electrode configuration; R0.5-plane and R6-plane. For a comparison purpose, this
section will focus only at 10 mm and 20 mm electrodes gap distance. As one can expect, the Ua
values of SF6/N2 gas mixtures under R6-plane configuration are higher than R0.5-plane
configuration for all pressure and both electrodes gap distances. However, it is found that
the difference in Ua values between both electrodes configurations is more significant at 10 mm
gap distance for all pressure. At 0.11 MPa, the Ua values differ about 33.6%. But, as the gap
distance is increased to 20 mm, the effect of electrode configurations in affecting the Ua values
is weaken, where the difference in Ua values reduce to 4.1%. From other point of view, it can be
seen that the Ua values under R0.5-plane configuration with 20 mm gap is almost identical to
R6-plane configuration with 10 mm gap, especially when the pressure is above 0.13 MPa.
Figure 4. Comparison of AC breakdown voltage of SF6/N2 gas mixtures in
different electrode configuration
3.4. Effect of Electrode Configurations to the Electric Field Behavior
Figure 5 shows the field efficiency factor of R0.5-plane and R6-plane electrode
configurations at a pressure of 0.11 MPa and various gap distances. The field efficiency factor,
η is calculated using (2), where the average electric field, Emean for both electrode configurations
are calculated using (3), while the maximum electric field, Emax for R0.5-plane and R6-plane
configurations are calculated using (4) and (5), respectively [25]. To note, 𝑑 is the gap distance
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AC breakdown behavior of SF6/N2 gas mixtures under non-uniform field... (H. Zainuddin)
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between high voltage and ground electrodes, while 𝑟 is the tip radius of the high voltage
electrode. The η value indicates the uniformity of electric field between the electrodes where its
value lies between 0 to 1. The closer the value of η to 1, the more uniform the electric field
exists between the electrodes. Based on Figure 5, it can be seen that the value of η under
R6-plane is higher than R0.5-plane at all gap distances. Meanwhile, a decreasing pattern of η
values are observed for both electrode configurations as the gap distances are increased which
suggesting a more non-uniform field exists between the electrodes.
η =
𝐸 𝑚𝑒𝑎𝑛
𝐸 𝑚𝑎𝑥
(2)
𝐸 𝑚𝑒𝑎𝑛 =
𝑈 𝑎
𝑑
(3)
𝐸 𝑚𝑎𝑥 =
2𝑈 𝑎
𝑟 𝑙𝑛(
4 𝑑
𝑟
)
(4)
𝐸 𝑚𝑎𝑥 = 0.9
𝑈 𝑎
𝑑
𝑟+𝑑
𝑟
(5)
Figure 5. Field efficiency factor of SF6/N2 gas mixtures as a function of gap distance under
different electrode configurations
4. Conclusion
In this study, a breakdown test subjected to AC voltage were conducted on the SF6/N2
gas mixtures for various gas mixture ratio, gas pressure, and electrode gap distance, under
R0.5-plane and R6-plane electrode configurations. The amount of SF6 was set to 10%, while
the pressure levels were varied at small range of 0.11 MPa to 0.15 MPa. Meanwhile, the gap
distances between the electrodes were set at 5 mm to 25 mm with 5 mm interval. The results
show that, for both electrodes configurations, the mean AC breakdown voltage, Ua of SF6/N2
gas mixtures increases as the pressure and electrodes gap distances are increased. It is also
observed that the effect of electrodes gap distance is more significant at lowest pressure of
0.11 MPa compared to other pressure levels. Although the Ua values under R6-plane
configuration is higher than R0.5-plane configuration, but, the difference in Ua values between
these electrodes configuration is less significant as the gap distance is increased. In addition, it
is found that the field efficiency factor value under R6-plane is higher than
R0.5-plane configurations.
References
[1] A Haddad, D Warne. Advances in High Voltage Engineering. 1st
ed. United Kingdom. The Institution
of Engineering and Technology. 2004.
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[2] A Beroual, A Haddad. Recent Advances in the Quest for a New Insulation Gas with a Low Impact on
the Environment to Replace Sulphur Hexafluoride (SF6) Gas in High-Voltage Power Network
Applications. Energies. 2017; 10(8): 1216.
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