Pub Date : 2017-06-18DOI: 10.1109/PPC.2017.8291172
J. O. Rossi, F. S. Yamasaki, E. Schamiloglu, Joaquim J. Barroso
This paper deals with the study of the gyromagnetic effect since it has proven to be an excellent way of generating radiofrequency (RF) using ferrite loaded nonlinear lines in the range of GHz. Using a proper mathematical model based on the analysis of the LLG (Landau-Lifshitz-Gilbert) equation will be demonstrated the dependence of the center frequency generated on both the intensity of the axial magnetic applied and the incident pulse amplitude.
{"title":"Analysis of nonlinear gyromagnetic line operation using LLG equation","authors":"J. O. Rossi, F. S. Yamasaki, E. Schamiloglu, Joaquim J. Barroso","doi":"10.1109/PPC.2017.8291172","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291172","url":null,"abstract":"This paper deals with the study of the gyromagnetic effect since it has proven to be an excellent way of generating radiofrequency (RF) using ferrite loaded nonlinear lines in the range of GHz. Using a proper mathematical model based on the analysis of the LLG (Landau-Lifshitz-Gilbert) equation will be demonstrated the dependence of the center frequency generated on both the intensity of the axial magnetic applied and the incident pulse amplitude.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123370427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-18DOI: 10.1109/PPC.2017.8291267
C. Y. Wu, Y. Cheng, C. Liao, H. P. Chang, C. Fann, D. Lee, K. Tsai, K. K. Lin, K. Hu, K. Hsu
The Taiwan Photon Source (TPS) is among the latest 3rd-generation 3-GeV synchrotron light source. Power supplies to control injection and extraction of the TPS pulsed magnets have been designed and implemented. Embedded Programmable Logic Controllers (PLCs) were developed to control the pulsed power supplies via the experimental physics and industrial control system (EPICS), which is remotely accessible with EPICS client tools. The timing system provides synchronous trigger signals for pulsed power supplies. Data acquisition systems with EPICS support are employed to observe the output current of the pulsed power supplies. The control system of these pulsed power supplies satisfies complete system integration, rich graphical user interfaces and useful diagnostic tools. It has been running without problems since mid-2014, which indicates its excellent reliability. A detailed description of the control system, operational interfaces, real-time monitoring system and diagnostic tools for the pulsed power supplies is presented in this paper.
{"title":"Control system and diagnostic tools for the TPS pulsed power supplies","authors":"C. Y. Wu, Y. Cheng, C. Liao, H. P. Chang, C. Fann, D. Lee, K. Tsai, K. K. Lin, K. Hu, K. Hsu","doi":"10.1109/PPC.2017.8291267","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291267","url":null,"abstract":"The Taiwan Photon Source (TPS) is among the latest 3rd-generation 3-GeV synchrotron light source. Power supplies to control injection and extraction of the TPS pulsed magnets have been designed and implemented. Embedded Programmable Logic Controllers (PLCs) were developed to control the pulsed power supplies via the experimental physics and industrial control system (EPICS), which is remotely accessible with EPICS client tools. The timing system provides synchronous trigger signals for pulsed power supplies. Data acquisition systems with EPICS support are employed to observe the output current of the pulsed power supplies. The control system of these pulsed power supplies satisfies complete system integration, rich graphical user interfaces and useful diagnostic tools. It has been running without problems since mid-2014, which indicates its excellent reliability. A detailed description of the control system, operational interfaces, real-time monitoring system and diagnostic tools for the pulsed power supplies is presented in this paper.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123761517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-18DOI: 10.1109/PPC.2017.8291297
H. Canacsinh, F. A. Silva, L. Redondo, P. Botelho
This paper proposes solutions to increase the range of the voltage droop compensation needed to generate long pulses in the generalized solid-state Marx modulator. A novel design method based on the use of resonant circuits in generalized bipolar solid-state Marx modulator is described and evaluated. The increase of the compensation range is obtained by adding an extra auxiliary resonant stage to the existing Marx stages without changing the modularity of the circuit. The compensation is obtained by synchronously adding the voltages of the auxiliary compensation stages to the output voltage. Simulation results are presented for eight stages Marx circuit, ~17% voltage droop, using 6kV bipolar pulses, 100ps pulse duration and 50Hz repetition frequency.
{"title":"Increasing the voltage droop compensation range in generalized bipolar solid-state Marx modulador","authors":"H. Canacsinh, F. A. Silva, L. Redondo, P. Botelho","doi":"10.1109/PPC.2017.8291297","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291297","url":null,"abstract":"This paper proposes solutions to increase the range of the voltage droop compensation needed to generate long pulses in the generalized solid-state Marx modulator. A novel design method based on the use of resonant circuits in generalized bipolar solid-state Marx modulator is described and evaluated. The increase of the compensation range is obtained by adding an extra auxiliary resonant stage to the existing Marx stages without changing the modularity of the circuit. The compensation is obtained by synchronously adding the voltages of the auxiliary compensation stages to the output voltage. Simulation results are presented for eight stages Marx circuit, ~17% voltage droop, using 6kV bipolar pulses, 100ps pulse duration and 50Hz repetition frequency.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123775167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-18DOI: 10.1109/PPC.2017.8291287
Xinyue Chang, Xinjie Yu, Xukun Liu, Zhen Li
As a new kind of kinetic-energy weapon system, electromagnetic railgun possesses one major advantage of high muzzle velocity which can be controlled artificially and accurately. Since the muzzle velocity error has a great influence on the hit rate, accurate velocity control is of importance. However, studies on muzzle velocity control are still inadequate. In order to solve this problem, the paper proposes a method to calculate the triggering strategy of the PFUs (Pulsed Forming Unit) of the pulsed power supplies. The armature acceleration process is equivalent to the uniform acceleration motion. And several velocity detecting devices are equidistantly placed along the rails. The triggering time of each PFU group is the moment when the armature passes by each velocity detecting device. The number of each PFU group is selected, based on the principle of minimizing the absolute error between the actual velocity and the ideal velocity (uniform acceleration) at the next velocity detecting device. In this way, the actual armature velocity waveform can coincide quite well with that of the ideal uniform acceleration process, thus the armature muzzle velocity can be controlled quite accurately. Simulations show that, with 0.15-kg armature mass and 6-m barrel length, if the target velocity is between 1.5 to 2 km/s, the control precision of the muzzle velocity is within 0.5%.
{"title":"Triggering strategy of railgun power supply for the accurate control of the armature muzzle velocity","authors":"Xinyue Chang, Xinjie Yu, Xukun Liu, Zhen Li","doi":"10.1109/PPC.2017.8291287","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291287","url":null,"abstract":"As a new kind of kinetic-energy weapon system, electromagnetic railgun possesses one major advantage of high muzzle velocity which can be controlled artificially and accurately. Since the muzzle velocity error has a great influence on the hit rate, accurate velocity control is of importance. However, studies on muzzle velocity control are still inadequate. In order to solve this problem, the paper proposes a method to calculate the triggering strategy of the PFUs (Pulsed Forming Unit) of the pulsed power supplies. The armature acceleration process is equivalent to the uniform acceleration motion. And several velocity detecting devices are equidistantly placed along the rails. The triggering time of each PFU group is the moment when the armature passes by each velocity detecting device. The number of each PFU group is selected, based on the principle of minimizing the absolute error between the actual velocity and the ideal velocity (uniform acceleration) at the next velocity detecting device. In this way, the actual armature velocity waveform can coincide quite well with that of the ideal uniform acceleration process, thus the armature muzzle velocity can be controlled quite accurately. Simulations show that, with 0.15-kg armature mass and 6-m barrel length, if the target velocity is between 1.5 to 2 km/s, the control precision of the muzzle velocity is within 0.5%.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115437090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-18DOI: 10.1109/PPC.2017.8291170
K. Thomas, P. Beech, S. Clough, R. Moodhoo, A. Stevens, K. Wales, M. Sinclair, J. Buck, J. Burscough, K. Davis, A. Hindle, A. White, J. Nicholls, D. Traylen, P. Bryant, C. Ewing, C. Younger, S. Jones, D. Grant, A. Jones, D. Goude, R. Williams, J. Threadgold, J. Nesbitt, P. Kilminster, H. Holmes, R. Shaw, M. Bell, B. Ambrose, J. Soulsby, S. Fraser, A. Gray, I. Huckle, A. Page, H. Seward, M. Toury, L. Hourdin
The MERLIN accelerator being commissioned at AWE in a new Technology Development Centre will provide one of the flash radiographic sources at a joint UK/French facility for hydrodynamic testing in support of the two nations' nuclear deterrents. The ten module Induction Voltage Adder (IVA) has been designed to provide a 60 ns long TerraWatt pulse to drive a Self Magnetic Pinch (SMP) electron beam diode at 7.5 MV. The design work for MERLIN was carried out by L3 Pulse Sciences in San Leandro, California and builds on previous IVA experience in the USA. Prototyping of sub-systems was also carried out by L3 to confirm that the performance and reliability requirements for the overall accelerator can be met. However, it is only now that all the components of the accelerator have been brought together and its overall function can be characterised and compared with predictions. Commissioning of the accelerator has involved setting to work the ancillary systems which provide and control oil, deionised water, sulphur hexafluoride gas, vacuum, control and instrumentation, diagnostics and data acquisition. With these operating satisfactorily testing of the pulsed power systems was able to commence. Commissioning of the pulsed power systems started with a run up of the Marx generator into a resistive load to its operating voltage of 2.5 MV, including characterisation of the trigger systems and the diverter switches. These are intended to short the Marx output after it reaches peak voltage, or if a prefire occurs, in order to reduce the risk of electrical breakdowns. The waveforms produced during factory tests in the US were successfully reproduced and the jitter of the trigger systems shown to meet specification. This allowed the commissioning programme to proceed to the active commissioning phase where an X-ray output is generated. Active commissioning is enabled by the Marx generator being connected via an oil insulated transfer line to the Pulse Forming Lines (PFLs). Each module of MERLIN comprises an induction cell driven by one of these PFLs. The upstream section of each PFL receives its 2.5 MV charge from the Marx generator on a microsecond timescale before its pulse forming action is initiated by a laser triggered gas switch. The laser triggering should provide nanosecond order synchronisation, and hence excellent pulse reproducibility, when the pulses are combined in the adder. The 60ns duration 1.1 MV outputs of the PFLs are fed to their corresponding induction cells which act to perform voltage addition along a 28 metre long 80 Ohm MITL. This delivers an 11 MV forward going wave to the e-beam diode. The pulsed radiographic source driven by MERLIN will be a SMP diode developed in an AWE led research programme in collaboration with US National Laboratories. This diode operates at approximately 40 Ohms with the result that retrapping of the MITL sheath current occurs transforming the 11 MV forward wave down to ∼ 7.5 MV while increasing the load current
{"title":"The MERLIN Induction Voltage Adder radiographic accelerator","authors":"K. Thomas, P. Beech, S. Clough, R. Moodhoo, A. Stevens, K. Wales, M. Sinclair, J. Buck, J. Burscough, K. Davis, A. Hindle, A. White, J. Nicholls, D. Traylen, P. Bryant, C. Ewing, C. Younger, S. Jones, D. Grant, A. Jones, D. Goude, R. Williams, J. Threadgold, J. Nesbitt, P. Kilminster, H. Holmes, R. Shaw, M. Bell, B. Ambrose, J. Soulsby, S. Fraser, A. Gray, I. Huckle, A. Page, H. Seward, M. Toury, L. Hourdin","doi":"10.1109/PPC.2017.8291170","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291170","url":null,"abstract":"The MERLIN accelerator being commissioned at AWE in a new Technology Development Centre will provide one of the flash radiographic sources at a joint UK/French facility for hydrodynamic testing in support of the two nations' nuclear deterrents. The ten module Induction Voltage Adder (IVA) has been designed to provide a 60 ns long TerraWatt pulse to drive a Self Magnetic Pinch (SMP) electron beam diode at 7.5 MV. The design work for MERLIN was carried out by L3 Pulse Sciences in San Leandro, California and builds on previous IVA experience in the USA. Prototyping of sub-systems was also carried out by L3 to confirm that the performance and reliability requirements for the overall accelerator can be met. However, it is only now that all the components of the accelerator have been brought together and its overall function can be characterised and compared with predictions. Commissioning of the accelerator has involved setting to work the ancillary systems which provide and control oil, deionised water, sulphur hexafluoride gas, vacuum, control and instrumentation, diagnostics and data acquisition. With these operating satisfactorily testing of the pulsed power systems was able to commence. Commissioning of the pulsed power systems started with a run up of the Marx generator into a resistive load to its operating voltage of 2.5 MV, including characterisation of the trigger systems and the diverter switches. These are intended to short the Marx output after it reaches peak voltage, or if a prefire occurs, in order to reduce the risk of electrical breakdowns. The waveforms produced during factory tests in the US were successfully reproduced and the jitter of the trigger systems shown to meet specification. This allowed the commissioning programme to proceed to the active commissioning phase where an X-ray output is generated. Active commissioning is enabled by the Marx generator being connected via an oil insulated transfer line to the Pulse Forming Lines (PFLs). Each module of MERLIN comprises an induction cell driven by one of these PFLs. The upstream section of each PFL receives its 2.5 MV charge from the Marx generator on a microsecond timescale before its pulse forming action is initiated by a laser triggered gas switch. The laser triggering should provide nanosecond order synchronisation, and hence excellent pulse reproducibility, when the pulses are combined in the adder. The 60ns duration 1.1 MV outputs of the PFLs are fed to their corresponding induction cells which act to perform voltage addition along a 28 metre long 80 Ohm MITL. This delivers an 11 MV forward going wave to the e-beam diode. The pulsed radiographic source driven by MERLIN will be a SMP diode developed in an AWE led research programme in collaboration with US National Laboratories. This diode operates at approximately 40 Ohms with the result that retrapping of the MITL sheath current occurs transforming the 11 MV forward wave down to ∼ 7.5 MV while increasing the load current","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129532752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-18DOI: 10.1109/PPC.2017.8291281
A. Civil, Ö. Cavbozar, M. Karagöz, E. Tan, Y. Çevik
Pulsed power supplies (PPS) deliver high currents in a short period of time. Designing a pulse shaping inductor (PSI) requires major effort because of the electromagnetic forces exerted on the windings due to high pulse currents. A pulse shaping foil inductor is simulated with the help of finite element software COMSOL Multiphysics. Two different mechanical structures are designed in order to increase the strength of the inductor. The PSIs are manufactured and tested as a component of a 200 kJ PPS module. Test results show that the final PSI prototype can operate without any significant damage when the PSI current reach to 160 kA. Improvement process still continues to make the PSI more enduring.
{"title":"Design and improvement of a pulse shaping inductor for a pulsed power system","authors":"A. Civil, Ö. Cavbozar, M. Karagöz, E. Tan, Y. Çevik","doi":"10.1109/PPC.2017.8291281","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291281","url":null,"abstract":"Pulsed power supplies (PPS) deliver high currents in a short period of time. Designing a pulse shaping inductor (PSI) requires major effort because of the electromagnetic forces exerted on the windings due to high pulse currents. A pulse shaping foil inductor is simulated with the help of finite element software COMSOL Multiphysics. Two different mechanical structures are designed in order to increase the strength of the inductor. The PSIs are manufactured and tested as a component of a 200 kJ PPS module. Test results show that the final PSI prototype can operate without any significant damage when the PSI current reach to 160 kA. Improvement process still continues to make the PSI more enduring.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123413596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-18DOI: 10.1109/PPC.2017.8291162
Anton I. Gusev, S. Lyubutin, A. Ponomarev, S. Rukin, B. Slovikovsky, S. Tsyranov
Operation of the thyristor-based switches triggered in impact-ionization wave mode has been investigated. The thyristor switch contained two series connected tablet thyristors having a silicon wafer of 56 mm in diameter. At applying across the switch a triggering pulse with a voltage rise rate dU/dt of over 1 kV/ns the thyristors transition time to conductive state was less than 1 ns. It is shown that the maximum amplitude of no-failure current is increased with increasing dU/dt at the triggering stage. A possible mechanism of the dU/dt value effect on the thyristors breakdown current is discussed. In safety operation regime at dU/dt = 6 kV/ns (3 kV/ns per a single thyristor) the switch discharged 1-mF capacitor, which was charged to a voltage of 5 kV, to a resistive load of 18 mΩ. The following results were obtained: a peak current was 200 kA, an initial dI/dt was 58 kA/ps, a FWHM was 25 ps, and switching efficiency was 0.97. It is shown that a temperature of the silicon wafer is one of the main factors that affects on the thyristor switching process. Results of the thyristors testing in pulse repetition mode are given also.
{"title":"High current and current rise rate thyristor based switches","authors":"Anton I. Gusev, S. Lyubutin, A. Ponomarev, S. Rukin, B. Slovikovsky, S. Tsyranov","doi":"10.1109/PPC.2017.8291162","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291162","url":null,"abstract":"Operation of the thyristor-based switches triggered in impact-ionization wave mode has been investigated. The thyristor switch contained two series connected tablet thyristors having a silicon wafer of 56 mm in diameter. At applying across the switch a triggering pulse with a voltage rise rate dU/dt of over 1 kV/ns the thyristors transition time to conductive state was less than 1 ns. It is shown that the maximum amplitude of no-failure current is increased with increasing dU/dt at the triggering stage. A possible mechanism of the dU/dt value effect on the thyristors breakdown current is discussed. In safety operation regime at dU/dt = 6 kV/ns (3 kV/ns per a single thyristor) the switch discharged 1-mF capacitor, which was charged to a voltage of 5 kV, to a resistive load of 18 mΩ. The following results were obtained: a peak current was 200 kA, an initial dI/dt was 58 kA/ps, a FWHM was 25 ps, and switching efficiency was 0.97. It is shown that a temperature of the silicon wafer is one of the main factors that affects on the thyristor switching process. Results of the thyristors testing in pulse repetition mode are given also.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128874141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-18DOI: 10.1109/PPC.2017.8291260
L. Dougall, Jonathan Gillespie, M. Maclean, I. Timoshkin, Mark P. Wilson, S. Macgregor
Airborne transmission of infectious organisms is a major public health concern, particularly within healthcare and communal public environments. Methods of environmental decontamination utilising pulsed ultraviolet (UV) light are currently available, however it is important that germicidal efficacy against airborne contamination is established. In this study bacterial aerosols were generated and exposed to short duration pulses (~20 μs) of UV-rich light emitted from a xenon-filled flashlamp. The lamp was operated using a 1 kV solid-state pulsed power source, with a pulse frequency of 1 Hz, and output energy of 20 J/pulse. Post-treatment, air samples were extracted from the chamber and the surviving fraction was enumerated using standard microbiological culture methods. Results demonstrate successful aerosol inactivation, with a 92.1% reduction achieved with only 5 pulses of UV-rich light (P=<0.0002). Inactivation using continuous UV light was also investigated in order to quantify the comparative efficacy of these antimicrobial light sources. Overall, results provide evidence of the comparative efficacy of pulsed and continuous UV light for inactivation of airborne bacterial contamination. For practical application, given the safety restrictions limiting its application for decontamination of unoccupied environments, or within sealed enclosures such as air handling units, the reduced treatment times with PUV provides significant operational advantages over continuous light treatment.
{"title":"Pulsed ultraviolet light decontamination of artifically-generated microbiological aerosols","authors":"L. Dougall, Jonathan Gillespie, M. Maclean, I. Timoshkin, Mark P. Wilson, S. Macgregor","doi":"10.1109/PPC.2017.8291260","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291260","url":null,"abstract":"Airborne transmission of infectious organisms is a major public health concern, particularly within healthcare and communal public environments. Methods of environmental decontamination utilising pulsed ultraviolet (UV) light are currently available, however it is important that germicidal efficacy against airborne contamination is established. In this study bacterial aerosols were generated and exposed to short duration pulses (~20 μs) of UV-rich light emitted from a xenon-filled flashlamp. The lamp was operated using a 1 kV solid-state pulsed power source, with a pulse frequency of 1 Hz, and output energy of 20 J/pulse. Post-treatment, air samples were extracted from the chamber and the surviving fraction was enumerated using standard microbiological culture methods. Results demonstrate successful aerosol inactivation, with a 92.1% reduction achieved with only 5 pulses of UV-rich light (P=<0.0002). Inactivation using continuous UV light was also investigated in order to quantify the comparative efficacy of these antimicrobial light sources. Overall, results provide evidence of the comparative efficacy of pulsed and continuous UV light for inactivation of airborne bacterial contamination. For practical application, given the safety restrictions limiting its application for decontamination of unoccupied environments, or within sealed enclosures such as air handling units, the reduced treatment times with PUV provides significant operational advantages over continuous light treatment.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130078492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.1109/PPC.2017.8291274
B. Song, I. Timoshkin, M. Maclean, M. Wilson, M. Given, S. Macgregor, K. Satoh, H. Kawaguchi
Pulsed electric field (PEF) may cause irreversible damage to bio-membranes of microorganisms, as electromechanical stresses induced across their membranes can stretch and rupture these phospholipid bi-layers. Local heating is important for further understanding of the biological action of the externally applied electric field as typically the PEF treatment is considered to be a nonthermal process: any increase in the global temperature of the microbial liquid suspension during this process does not result in the thermal inactivation of microorganisms. This paper is aimed at investigation of the transient local heating and transient mechanical stresses across biomembranes of model microorganisms stressed with the external electric field using a model developed in COMSOL Multiphysics. The obtained results demonstrate that high-field impulses can result in the development of strong local electro-mechanical stresses across the membrane, and significant local over-heating of the membrane and the cell wall, as compared with the global temperature of the external suspension. These results and the developed model can help in further understanding the biological action of the impulsive electric fields, and in further development and optimisation of the PEF technology.
{"title":"Local heating and stresses across membranes of microorganisms stressed with electric field","authors":"B. Song, I. Timoshkin, M. Maclean, M. Wilson, M. Given, S. Macgregor, K. Satoh, H. Kawaguchi","doi":"10.1109/PPC.2017.8291274","DOIUrl":"https://doi.org/10.1109/PPC.2017.8291274","url":null,"abstract":"Pulsed electric field (PEF) may cause irreversible damage to bio-membranes of microorganisms, as electromechanical stresses induced across their membranes can stretch and rupture these phospholipid bi-layers. Local heating is important for further understanding of the biological action of the externally applied electric field as typically the PEF treatment is considered to be a nonthermal process: any increase in the global temperature of the microbial liquid suspension during this process does not result in the thermal inactivation of microorganisms. This paper is aimed at investigation of the transient local heating and transient mechanical stresses across biomembranes of model microorganisms stressed with the external electric field using a model developed in COMSOL Multiphysics. The obtained results demonstrate that high-field impulses can result in the development of strong local electro-mechanical stresses across the membrane, and significant local over-heating of the membrane and the cell wall, as compared with the global temperature of the external suspension. These results and the developed model can help in further understanding the biological action of the impulsive electric fields, and in further development and optimisation of the PEF technology.","PeriodicalId":247019,"journal":{"name":"2017 IEEE 21st International Conference on Pulsed Power (PPC)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121239750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.1109/PPC.2017.8291099
I. Bunin, V. Chanturiya, M. Ryazantseva, I. Khabarova, N. Anashkina
The application of High-Power Electromagnetic Pulses (HPEMP) in dressing of resistant gold-containing ores appears attractive as this technique provides for a significant increase in precious metal recovery in hydrometallurgical (gold and silver) and gravitational (PGM) processes [1-3]. The present work studies the effect of high-voltage nanosecond pulses on the phase composition of surface layers, physical-chemical and technological (flotation) properties of sulfide minerals with different semiconductor properties and natural dielectric minerals using a complex of physical and chemical methods (XPS, SEM-EDX, AFM), microhardness measurement (Vickers indentation method).
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