Dr. Abdur Razzak - Academia.edu (original) (raw)

Papers by Dr. Abdur Razzak

Research paper thumbnail of Sustainable Microgrid Analysis for Kutubdia Island of Bangladesh

IEEE Access

Uninterrupted power supply with sustainable microgrid remains a big challenge for Kutubdia Island... more Uninterrupted power supply with sustainable microgrid remains a big challenge for Kutubdia Island in Bangladesh. However, the majority of study has been focused on the techno-economic aspects of producing electricity in support of this isolated area. To bridge the gap, the present study proposes a methodology for assessing off-grid hybrid microgrid pertaining to the priorities of four key sustainability performance indicators (KSPI): economy, environment, technology, and society. The evaluation process also includes total 13 sets of sub-indicators under KSPI, such as levelized cost of energy, return on investment, CO 2 emissions, renewable fraction, excess electricity, unmet load, land usage, job creation etc. The comprehensive value of KSPI regarding economic, environmental, technical, and social priorities are computed using fuzzy logic Mamdani type rules, which facilitates human judgment in linguistic terms and eliminates weightage ambiguity. Seven microgrid scenarios integrating locally accessible resources have been scored and ranked to identify suitable configuration. According to the findings, the PV/Wind/Diesel/Converter/Battery combination reveals best option considering economic priority. On the other hand, the PV/Wind/Converter/Battery alternative receives excellent performance scores and is recommended in both environmental and social categories. However, the PV/Diesel/Converter/Battery arrangement outperforms the others architectures and gets preference for technical reasons. Additionally, the electrical, financial, emission, and sensitivity analysis are carried out for a selected microgrid in Kutubdia. This assessment framework can assist academics, policymakers and investors for planning microgrid in a better way based on sustainable dimensions.

Research paper thumbnail of A Cost Effective UV Robot for Disinfecting Hospital and Factory Spaces for Covid-19 and Other Communicable Diseases

2021 IEEE World AI IoT Congress (AIIoT), 2021

This paper presents a cost effective UV robot for applications of disinfecting hospital and facto... more This paper presents a cost effective UV robot for applications of disinfecting hospital and factory spaces from Covid-19 and other communicable diseases. This is based on a disinfection method using a remotely controlled UltraViolet (UV) disinfection robot. The robot is equipped with 3 UVC lamps in a 360 degree beam coverage setting, on a mobile base which is equipped with motors, controllers and sensors that allow the lamps to move around and disinfect surfaces with ease. The robot can automatically detect human and or other types of non-living presence over which machine learning models are built that allows for some degree of autonomous control. Its main control unit is operated via WiFi using the mobile as a transceiver device allowing for remote safe control of UVC lamp disinfection.

Research paper thumbnail of Measurement of electromagnetic field in a radio frequency inductively coupled plasma at atmospheric pressure

The 33rd IEEE International Conference on Plasma Science, 2006. ICOPS 2006. IEEE Conference Record - Abstracts., 2006

ABSTRACT

Research paper thumbnail of Design and Implementation of a Low-Cost Power Diagnosis Node for Monitoring the Stand-Alone PV System in the Mockery of IoT

Advances in Automation, Signal Processing, Instrumentation, and Control, 2021

Research paper thumbnail of Electric Cooking Diary in Bangladesh: Energy Requirement, Cost of Cooking Fuel, Prospects, and Challenges

Energies, 2021

Detrimental effects exerted by biomass-based traditional cookstoves on health, environment, hygie... more Detrimental effects exerted by biomass-based traditional cookstoves on health, environment, hygiene, and the soaring price of gas makes it imperative to investigate the feasibility of electric cooking as a promising clean cooking fuel in the context of Bangladesh. However, the adoption of electric cooking is unlikely to be welcomed if the monthly cost of electricity consumed by the electric cooking appliances is not comparable to traditional cooking fuels. So far, no study has been reported in this respect. Therefore, this paper is aimed to assess the energy consumption of available electric cooking appliances for cooking typical Bangladeshi dishes. Estimated monthly electricity cost of electric cooking is also reported and then compared to that of traditional cooking fuels. For the study purpose, three respondent families were provided with a rice cooker, hot plate, induction cooker and electric pressure cooker for cooking their daily meals. After four months of use, data related t...

Research paper thumbnail of Performance Evaluation of a PID-Controlled Synchronous Buck Converter Based Battery Charging Controller for Solar-Powered Lighting System in a Fishing Trawler

Energies, 2018

A Proportional-Integral-Derivative (PID)-controlled synchronous buck converter (SBC)-based batter... more A Proportional-Integral-Derivative (PID)-controlled synchronous buck converter (SBC)-based battery charging system was designed to charge a lead-acid cell battery using commercially available Photovoltaic (PV) panel. The proposed system was installed aboard a fishing trawler to power its electrical system replacing the conventional system, which uses a diesel generator and a few kerosene lamps for lighting purposes. A PID algorithm instead of traditional Maximum power point tracker (MPPT) is used in the proposed system since the charging process of the battery requires a maximum current instead of maximum power. The proposed control algorithm is compared with the popular MPPT technique Perturb and Observation (P&O) to validate its dynamic performance at different solar irradiance levels using MATLAB/Simulink®. The simulation and the experimental results have demonstrated that the dynamic response of the proposed algorithm is significantly improved by considering higher charging curr...

Research paper thumbnail of 01pC23P Effects of Tungsten Electrode on the Initiation of High-Pressure Induction Plasmas

プラズマ 核融合学会年会予稿集, Nov 20, 2005

Research paper thumbnail of Coupling Characteristics of Induction Coil in Atmospheric Pressure Inductively Coupled Plasmas

IEEE International Conference on Plasma Science

ABSTRACT

Research paper thumbnail of Transient Behaviors of a Radio Frequency Pulse-Modulated Argon Inductively Coupled Plasma in Atmospheric Pressure

Research paper thumbnail of Design of a transformer-less grid-tie inverter using dual-stage buck & boost converters

International Journal of Renewable Energy Research

This paper introduces a topology for transformer-less pure sine wave grid-tie inverter (GTI) for ... more This paper introduces a topology for transformer-less pure sine wave grid-tie inverter (GTI) for photovoltaic (PV) applications. The proposed GTI employs a dual-stage switch mode boost converter, a dual-stage switch mode buck converter, an H-bridge inverter and a T-LCL immittance conversion circuit. For switching of GTI power circuit, a combination of sinusoidal pulse width modulation (SPWM) and square wave signal under grid synchronization conditions are applied. As the suggested method is entirely transformer-less, it astonishingly reduces Total Harmonic Distortion (THD) which is less than 0.1%, minimizes the size of the inverter and increases inverter efficiency up to 97%. The T-LCL immittance conversion circuit not only reduces the harmonic distortation of inverter output but also provides a nearly constant output current thereby stabilizing the system instanteously. Using the designed values of circuit components, the overall performance of the proposed inverter is simulated by using PSIM software. The simulation results not only show that the proposed inverter eliminates vast harmonics but also prove that it is highly efficient, compact in size and cost effective due to being transformer-less.

Research paper thumbnail of Design of a Novel T-LCL Immittance Conversion Circuit for Dynamic and Non-Linear Loads

2006 International Conference on Electrical and Computer Engineering, 2006

... Bangladesh DESIGN OF A NOVEL T-LCL IMMITTANCE CONVERSION CIRCUIT FOR DYNAMIC AND NON-LINEAR L... more ... Bangladesh DESIGN OF A NOVEL T-LCL IMMITTANCE CONVERSION CIRCUIT FOR DYNAMIC AND NON-LINEAR LOADS M Abdur Razzak', Shuichi Takamura2, Noriyasu Ohno3, and Yoshihiko Uesugi4 'School ofEngineering ...

Research paper thumbnail of Single phase grid-connected photovoltaic inverter for residential application with maximum power point tracking

2013 International Conference on Informatics, Electronics and Vision (ICIEV), 2013

Research paper thumbnail of On the performance of M-ary modulation schemes for efficient communication systems

2007 10th International Conference on Computer and Information Technology, 2007

Abstract—In this paper, the performances of M-ary modulation schemes (MPSK, MQAM and MFSK) are an... more Abstract—In this paper, the performances of M-ary modulation schemes (MPSK, MQAM and MFSK) are analyzed in terms of symbol error probability as a function of SNR per bit. The channel capacity in terms of bit rate per bandwidth is also investigated to analyze the ...

Research paper thumbnail of Multiple description image coding: A low complexity approach for lossy networks

TENCON 2008 - 2008 IEEE Region 10 Conference, 2008

Abstract The development of an efficient and reliable multiple descriptions coding (MDC) scheme o... more Abstract The development of an efficient and reliable multiple descriptions coding (MDC) scheme over lossy communication networks has been described. The advantage of MDC is that, if all the channels work, a high quality, possibly lossless, reconstruction can be achieved from all the received descriptions. On the other hand, a lower but still acceptable quality can be achieved if some of the channels are not received at all. In this article, a general framework of an efficient multiple description robust communication system with 2 ...

Research paper thumbnail of A π-CLCL Type Immittance Converter for Constant Current and Dynamic Load Applications

International Journal of Electrical and Computer Engineering (IJECE), 2014

Impedance-admittance converter is shortly termed as immittance converter. In this converter, the ... more Impedance-admittance converter is shortly termed as immittance converter. In this converter, the output current is proportional to the input voltage and the output voltage is proportional to the input current. The output current is thus independent of the load. This research evaluates the characteristics of a proposed π-CLCL immittance converter, which is a combination of the typical π-and T-type configurations, for constant current and dynamic load applications. The input-output characteristics and efficiency characteristics are analyzed and simulated. The characteristics are compared to that of the typical π-and T-type converters. The input-output characteristics and efficiency characteristics are then examined experimentally. It is observed that the experimental results agree with those of the simulation ones, and confirm that the π-CLCL configuration is more efficient than the typical πand T-type immittance converters while maintaining a nearly constant output current and thus applicable for dynamic loads.

Research paper thumbnail of Validity of Electron Temperature Measurement by Using Boltzmann Plot Method in Radio Frequency Inductive Discharge in the Atmospheric Pressure Range

Plasma and Fusion Research, 2006

The validity of electron temperature measurement using the Boltzmann plot method was investigated... more The validity of electron temperature measurement using the Boltzmann plot method was investigated in a radio frequency (rf) inductive discharge in the atmospheric pressure range. Since the Boltzmann plot method requires local thermal equilibrium (LTE), the parameter regions of electron temperature and electron density, in which the Boltzmann plot method is applicable, were analyzed in terms of a comparison of the spontaneous emission and collisional excitation to the excited states. It is observed that in our rf-inductive plasma near the atmospheric pressure range the Boltzmann plot method does not provide an exact measurement of electron temperature because of relatively low electron density, which does not satisfy the calculation criteria. An alternative method employing a combination of the Stark broadening measurement and the Saha-Boltzmann equation was demonstrated to more accurately determine the plasma parameters (electron temperature and electron density).

Research paper thumbnail of Measurement of Electric Field Distribution along the Plasma Column in Microwave Jet Discharges at Atmospheric Pressure

Plasma and Fusion Research, 2009

A new technique for the direct measurement of electric field distribution along the plasma column... more A new technique for the direct measurement of electric field distribution along the plasma column in microwave jet discharges is developed and employed. The technique is based on a servomotor-controlled reciprocating antenna moving along the nozzle axis and plasma column. The measurement technique is applied to a rectangular waveguide-based 2.45 GHz argon and helium plasma jets generated by using the modified TIAGO nozzle at atmospheric pressure with a microwave power of less than 500 W. The measurement has been done with and without igniting the plasma jet in order to investigate the standing wave propagation along the nozzle axis and plasma column. It is observed that the electric field decay occurs slowly in space with plasma ignition than that of without plasma, which indicates the surface electromagnetic wave propagation along the plasma column in order to sustain the plasma jet. This study enables one to design, determine and optimize the size and structure of launcher nozzle, which plays an important role for the stable and efficient microwave plasma generators.

Research paper thumbnail of Multiple description discrete cosine transform-based image coding using DC coefficient relocation and AC coefficient interpolation

Journal of Electronic Imaging, 2013

ABSTRACT Abstract. The development of an effective and dependable multiple description coding sch... more ABSTRACT Abstract. The development of an effective and dependable multiple description coding scheme over a lossy communication system is described. A general framework of an effective multiple description robust communication system with two-channel and four-channel cases is presented with a proposed block-based DC coefficient relo- cation and AC coefficient interpolation approach. A benefit of such system is that, if all the channels work properly, a very good quality, probably lossless, reconstruction can be obtained from the received descriptions. On the other hand, if some of the channels do not work properly, a lower but still quiet satisfactory quality of reconstruction can be obtained. The performance of the proposed scheme is mea- sured with mean squared error, peak signal-to-noise ratio, entropy, and bit rate to analyze the reconstruction quality, and the computed results are matched with that of the other schemes. The system complexity is also computed and compared. Comparing the simula- tion results, it is observed that the proposed scheme, which uses a DC coefficient relocation and AC coefficient interpolation scheme, gives comprehensive enhancements over the other recently devel- oped schemes. © 2013 SPIE and IS&T [DOI: 10.1117/1.JEI.22.2 .023030]

Research paper thumbnail of Transition from electrostatic-to-electromagnetic mode in a radio-frequency Ar inductively coupled plasma in atmospheric pressure

Journal of Applied Physics, 2004

The dynamics of mode transition from the electrostatic ͑E͒ to electromagnetic ͑H͒ mode of a radio... more The dynamics of mode transition from the electrostatic ͑E͒ to electromagnetic ͑H͒ mode of a radio-frequency argon inductively coupled plasma ͑ICP͒ in atmospheric pressure is investigated, both experimentally and theoretically. High-speed ͑4500 f/s͒ camera imaging is performed to investigate the dynamics of E-H discharge mode transition. The temporal plasma loading impedance of Ar inductive discharges at the E-H transition stage is also observed to investigate the transition dynamics. The experimental observations reveal that the formation of the multiple streamerlike electrostatic discharge paths followed by the strong ring-shaped azimuthal discharges leads to ignite the high-pressure ͑around 1 atm or more͒ ICPs. The time scale of E-H discharge mode transition is estimated by using proposed models and the estimated results are compared with that of the experimental one. It is found that the estimated results agree well with that of the experimental one.

Research paper thumbnail of Development of asymmetric double probe formula and its application for collisional plasmas

Journal of Applied Physics, 2010

ABSTRACT The ratio of the electron and ion saturation currents in single probe I-V characteristic... more ABSTRACT The ratio of the electron and ion saturation currents in single probe I-V characteristics for microwave-sustained plasma jets at atmospheric pressure are found to be much smaller than the value expected from the standard high-pressure single probe theory providing an over estimation of electron temperatures. By assuming that the single probe characteristic behaves as an asymmetric double probe when the electron to ion saturation current ratio is reduced, the whole characteristics may be fitted and significantly lower electron temperatures may be derived. In this study, asymmetric double probe theory for collisional plasmas is developed and employed to microwave-sustained helium plasma jets in order to estimate the plasma parameters (electron temperature and plasma density) at atmospheric pressure avoiding the overestimation of electron temperature.

Research paper thumbnail of Sustainable Microgrid Analysis for Kutubdia Island of Bangladesh

IEEE Access

Uninterrupted power supply with sustainable microgrid remains a big challenge for Kutubdia Island... more Uninterrupted power supply with sustainable microgrid remains a big challenge for Kutubdia Island in Bangladesh. However, the majority of study has been focused on the techno-economic aspects of producing electricity in support of this isolated area. To bridge the gap, the present study proposes a methodology for assessing off-grid hybrid microgrid pertaining to the priorities of four key sustainability performance indicators (KSPI): economy, environment, technology, and society. The evaluation process also includes total 13 sets of sub-indicators under KSPI, such as levelized cost of energy, return on investment, CO 2 emissions, renewable fraction, excess electricity, unmet load, land usage, job creation etc. The comprehensive value of KSPI regarding economic, environmental, technical, and social priorities are computed using fuzzy logic Mamdani type rules, which facilitates human judgment in linguistic terms and eliminates weightage ambiguity. Seven microgrid scenarios integrating locally accessible resources have been scored and ranked to identify suitable configuration. According to the findings, the PV/Wind/Diesel/Converter/Battery combination reveals best option considering economic priority. On the other hand, the PV/Wind/Converter/Battery alternative receives excellent performance scores and is recommended in both environmental and social categories. However, the PV/Diesel/Converter/Battery arrangement outperforms the others architectures and gets preference for technical reasons. Additionally, the electrical, financial, emission, and sensitivity analysis are carried out for a selected microgrid in Kutubdia. This assessment framework can assist academics, policymakers and investors for planning microgrid in a better way based on sustainable dimensions.

Research paper thumbnail of A Cost Effective UV Robot for Disinfecting Hospital and Factory Spaces for Covid-19 and Other Communicable Diseases

2021 IEEE World AI IoT Congress (AIIoT), 2021

This paper presents a cost effective UV robot for applications of disinfecting hospital and facto... more This paper presents a cost effective UV robot for applications of disinfecting hospital and factory spaces from Covid-19 and other communicable diseases. This is based on a disinfection method using a remotely controlled UltraViolet (UV) disinfection robot. The robot is equipped with 3 UVC lamps in a 360 degree beam coverage setting, on a mobile base which is equipped with motors, controllers and sensors that allow the lamps to move around and disinfect surfaces with ease. The robot can automatically detect human and or other types of non-living presence over which machine learning models are built that allows for some degree of autonomous control. Its main control unit is operated via WiFi using the mobile as a transceiver device allowing for remote safe control of UVC lamp disinfection.

Research paper thumbnail of Measurement of electromagnetic field in a radio frequency inductively coupled plasma at atmospheric pressure

The 33rd IEEE International Conference on Plasma Science, 2006. ICOPS 2006. IEEE Conference Record - Abstracts., 2006

ABSTRACT

Research paper thumbnail of Design and Implementation of a Low-Cost Power Diagnosis Node for Monitoring the Stand-Alone PV System in the Mockery of IoT

Advances in Automation, Signal Processing, Instrumentation, and Control, 2021

Research paper thumbnail of Electric Cooking Diary in Bangladesh: Energy Requirement, Cost of Cooking Fuel, Prospects, and Challenges

Energies, 2021

Detrimental effects exerted by biomass-based traditional cookstoves on health, environment, hygie... more Detrimental effects exerted by biomass-based traditional cookstoves on health, environment, hygiene, and the soaring price of gas makes it imperative to investigate the feasibility of electric cooking as a promising clean cooking fuel in the context of Bangladesh. However, the adoption of electric cooking is unlikely to be welcomed if the monthly cost of electricity consumed by the electric cooking appliances is not comparable to traditional cooking fuels. So far, no study has been reported in this respect. Therefore, this paper is aimed to assess the energy consumption of available electric cooking appliances for cooking typical Bangladeshi dishes. Estimated monthly electricity cost of electric cooking is also reported and then compared to that of traditional cooking fuels. For the study purpose, three respondent families were provided with a rice cooker, hot plate, induction cooker and electric pressure cooker for cooking their daily meals. After four months of use, data related t...

Research paper thumbnail of Performance Evaluation of a PID-Controlled Synchronous Buck Converter Based Battery Charging Controller for Solar-Powered Lighting System in a Fishing Trawler

Energies, 2018

A Proportional-Integral-Derivative (PID)-controlled synchronous buck converter (SBC)-based batter... more A Proportional-Integral-Derivative (PID)-controlled synchronous buck converter (SBC)-based battery charging system was designed to charge a lead-acid cell battery using commercially available Photovoltaic (PV) panel. The proposed system was installed aboard a fishing trawler to power its electrical system replacing the conventional system, which uses a diesel generator and a few kerosene lamps for lighting purposes. A PID algorithm instead of traditional Maximum power point tracker (MPPT) is used in the proposed system since the charging process of the battery requires a maximum current instead of maximum power. The proposed control algorithm is compared with the popular MPPT technique Perturb and Observation (P&O) to validate its dynamic performance at different solar irradiance levels using MATLAB/Simulink®. The simulation and the experimental results have demonstrated that the dynamic response of the proposed algorithm is significantly improved by considering higher charging curr...

Research paper thumbnail of 01pC23P Effects of Tungsten Electrode on the Initiation of High-Pressure Induction Plasmas

プラズマ 核融合学会年会予稿集, Nov 20, 2005

Research paper thumbnail of Coupling Characteristics of Induction Coil in Atmospheric Pressure Inductively Coupled Plasmas

IEEE International Conference on Plasma Science

ABSTRACT

Research paper thumbnail of Transient Behaviors of a Radio Frequency Pulse-Modulated Argon Inductively Coupled Plasma in Atmospheric Pressure

Research paper thumbnail of Design of a transformer-less grid-tie inverter using dual-stage buck & boost converters

International Journal of Renewable Energy Research

This paper introduces a topology for transformer-less pure sine wave grid-tie inverter (GTI) for ... more This paper introduces a topology for transformer-less pure sine wave grid-tie inverter (GTI) for photovoltaic (PV) applications. The proposed GTI employs a dual-stage switch mode boost converter, a dual-stage switch mode buck converter, an H-bridge inverter and a T-LCL immittance conversion circuit. For switching of GTI power circuit, a combination of sinusoidal pulse width modulation (SPWM) and square wave signal under grid synchronization conditions are applied. As the suggested method is entirely transformer-less, it astonishingly reduces Total Harmonic Distortion (THD) which is less than 0.1%, minimizes the size of the inverter and increases inverter efficiency up to 97%. The T-LCL immittance conversion circuit not only reduces the harmonic distortation of inverter output but also provides a nearly constant output current thereby stabilizing the system instanteously. Using the designed values of circuit components, the overall performance of the proposed inverter is simulated by using PSIM software. The simulation results not only show that the proposed inverter eliminates vast harmonics but also prove that it is highly efficient, compact in size and cost effective due to being transformer-less.

Research paper thumbnail of Design of a Novel T-LCL Immittance Conversion Circuit for Dynamic and Non-Linear Loads

2006 International Conference on Electrical and Computer Engineering, 2006

... Bangladesh DESIGN OF A NOVEL T-LCL IMMITTANCE CONVERSION CIRCUIT FOR DYNAMIC AND NON-LINEAR L... more ... Bangladesh DESIGN OF A NOVEL T-LCL IMMITTANCE CONVERSION CIRCUIT FOR DYNAMIC AND NON-LINEAR LOADS M Abdur Razzak', Shuichi Takamura2, Noriyasu Ohno3, and Yoshihiko Uesugi4 'School ofEngineering ...

Research paper thumbnail of Single phase grid-connected photovoltaic inverter for residential application with maximum power point tracking

2013 International Conference on Informatics, Electronics and Vision (ICIEV), 2013

Research paper thumbnail of On the performance of M-ary modulation schemes for efficient communication systems

2007 10th International Conference on Computer and Information Technology, 2007

Abstract—In this paper, the performances of M-ary modulation schemes (MPSK, MQAM and MFSK) are an... more Abstract—In this paper, the performances of M-ary modulation schemes (MPSK, MQAM and MFSK) are analyzed in terms of symbol error probability as a function of SNR per bit. The channel capacity in terms of bit rate per bandwidth is also investigated to analyze the ...

Research paper thumbnail of Multiple description image coding: A low complexity approach for lossy networks

TENCON 2008 - 2008 IEEE Region 10 Conference, 2008

Abstract The development of an efficient and reliable multiple descriptions coding (MDC) scheme o... more Abstract The development of an efficient and reliable multiple descriptions coding (MDC) scheme over lossy communication networks has been described. The advantage of MDC is that, if all the channels work, a high quality, possibly lossless, reconstruction can be achieved from all the received descriptions. On the other hand, a lower but still acceptable quality can be achieved if some of the channels are not received at all. In this article, a general framework of an efficient multiple description robust communication system with 2 ...

Research paper thumbnail of A π-CLCL Type Immittance Converter for Constant Current and Dynamic Load Applications

International Journal of Electrical and Computer Engineering (IJECE), 2014

Impedance-admittance converter is shortly termed as immittance converter. In this converter, the ... more Impedance-admittance converter is shortly termed as immittance converter. In this converter, the output current is proportional to the input voltage and the output voltage is proportional to the input current. The output current is thus independent of the load. This research evaluates the characteristics of a proposed π-CLCL immittance converter, which is a combination of the typical π-and T-type configurations, for constant current and dynamic load applications. The input-output characteristics and efficiency characteristics are analyzed and simulated. The characteristics are compared to that of the typical π-and T-type converters. The input-output characteristics and efficiency characteristics are then examined experimentally. It is observed that the experimental results agree with those of the simulation ones, and confirm that the π-CLCL configuration is more efficient than the typical πand T-type immittance converters while maintaining a nearly constant output current and thus applicable for dynamic loads.

Research paper thumbnail of Validity of Electron Temperature Measurement by Using Boltzmann Plot Method in Radio Frequency Inductive Discharge in the Atmospheric Pressure Range

Plasma and Fusion Research, 2006

The validity of electron temperature measurement using the Boltzmann plot method was investigated... more The validity of electron temperature measurement using the Boltzmann plot method was investigated in a radio frequency (rf) inductive discharge in the atmospheric pressure range. Since the Boltzmann plot method requires local thermal equilibrium (LTE), the parameter regions of electron temperature and electron density, in which the Boltzmann plot method is applicable, were analyzed in terms of a comparison of the spontaneous emission and collisional excitation to the excited states. It is observed that in our rf-inductive plasma near the atmospheric pressure range the Boltzmann plot method does not provide an exact measurement of electron temperature because of relatively low electron density, which does not satisfy the calculation criteria. An alternative method employing a combination of the Stark broadening measurement and the Saha-Boltzmann equation was demonstrated to more accurately determine the plasma parameters (electron temperature and electron density).

Research paper thumbnail of Measurement of Electric Field Distribution along the Plasma Column in Microwave Jet Discharges at Atmospheric Pressure

Plasma and Fusion Research, 2009

A new technique for the direct measurement of electric field distribution along the plasma column... more A new technique for the direct measurement of electric field distribution along the plasma column in microwave jet discharges is developed and employed. The technique is based on a servomotor-controlled reciprocating antenna moving along the nozzle axis and plasma column. The measurement technique is applied to a rectangular waveguide-based 2.45 GHz argon and helium plasma jets generated by using the modified TIAGO nozzle at atmospheric pressure with a microwave power of less than 500 W. The measurement has been done with and without igniting the plasma jet in order to investigate the standing wave propagation along the nozzle axis and plasma column. It is observed that the electric field decay occurs slowly in space with plasma ignition than that of without plasma, which indicates the surface electromagnetic wave propagation along the plasma column in order to sustain the plasma jet. This study enables one to design, determine and optimize the size and structure of launcher nozzle, which plays an important role for the stable and efficient microwave plasma generators.

Research paper thumbnail of Multiple description discrete cosine transform-based image coding using DC coefficient relocation and AC coefficient interpolation

Journal of Electronic Imaging, 2013

ABSTRACT Abstract. The development of an effective and dependable multiple description coding sch... more ABSTRACT Abstract. The development of an effective and dependable multiple description coding scheme over a lossy communication system is described. A general framework of an effective multiple description robust communication system with two-channel and four-channel cases is presented with a proposed block-based DC coefficient relo- cation and AC coefficient interpolation approach. A benefit of such system is that, if all the channels work properly, a very good quality, probably lossless, reconstruction can be obtained from the received descriptions. On the other hand, if some of the channels do not work properly, a lower but still quiet satisfactory quality of reconstruction can be obtained. The performance of the proposed scheme is mea- sured with mean squared error, peak signal-to-noise ratio, entropy, and bit rate to analyze the reconstruction quality, and the computed results are matched with that of the other schemes. The system complexity is also computed and compared. Comparing the simula- tion results, it is observed that the proposed scheme, which uses a DC coefficient relocation and AC coefficient interpolation scheme, gives comprehensive enhancements over the other recently devel- oped schemes. © 2013 SPIE and IS&T [DOI: 10.1117/1.JEI.22.2 .023030]

Research paper thumbnail of Transition from electrostatic-to-electromagnetic mode in a radio-frequency Ar inductively coupled plasma in atmospheric pressure

Journal of Applied Physics, 2004

The dynamics of mode transition from the electrostatic ͑E͒ to electromagnetic ͑H͒ mode of a radio... more The dynamics of mode transition from the electrostatic ͑E͒ to electromagnetic ͑H͒ mode of a radio-frequency argon inductively coupled plasma ͑ICP͒ in atmospheric pressure is investigated, both experimentally and theoretically. High-speed ͑4500 f/s͒ camera imaging is performed to investigate the dynamics of E-H discharge mode transition. The temporal plasma loading impedance of Ar inductive discharges at the E-H transition stage is also observed to investigate the transition dynamics. The experimental observations reveal that the formation of the multiple streamerlike electrostatic discharge paths followed by the strong ring-shaped azimuthal discharges leads to ignite the high-pressure ͑around 1 atm or more͒ ICPs. The time scale of E-H discharge mode transition is estimated by using proposed models and the estimated results are compared with that of the experimental one. It is found that the estimated results agree well with that of the experimental one.

Research paper thumbnail of Development of asymmetric double probe formula and its application for collisional plasmas

Journal of Applied Physics, 2010

ABSTRACT The ratio of the electron and ion saturation currents in single probe I-V characteristic... more ABSTRACT The ratio of the electron and ion saturation currents in single probe I-V characteristics for microwave-sustained plasma jets at atmospheric pressure are found to be much smaller than the value expected from the standard high-pressure single probe theory providing an over estimation of electron temperatures. By assuming that the single probe characteristic behaves as an asymmetric double probe when the electron to ion saturation current ratio is reduced, the whole characteristics may be fitted and significantly lower electron temperatures may be derived. In this study, asymmetric double probe theory for collisional plasmas is developed and employed to microwave-sustained helium plasma jets in order to estimate the plasma parameters (electron temperature and plasma density) at atmospheric pressure avoiding the overestimation of electron temperature.