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Papers by Valerie Leveille
Thermal Spray 2003: Proceedings from the International Thermal Spray Conference
In this study, two complementary techniques of diagnostic are used to study the properties of a s... more In this study, two complementary techniques of diagnostic are used to study the properties of a supersonic HF plasma flow: namely, an enthalpy probe measurement and a flow visualization. A PL-35 induction plasma torch operating with three convergent-divergent Laval-type nozzles generates the plasma: a Mach 3.0 velocity water-cooled (wc) nozzle, a Mach 1.5 velocity wc nozzle and a Mach 2.45 velocity radiation-cooled (rc) nozzle. The plasma plate power is fixed at 20 kW and chamber pressure varies between 1 and 10 kPa. The plasma gas is argon and its flow is fixed at 60 slpm. The enthalpy probe profiles of local enthalpy and stagnation pressure are measured, from which, temperature, velocity and Mach number are obtained. The effect of nozzle design on plasma properties is investigated. The RC nozzle creates a plasma jet hotter with a steeper thermal profile and a higher mean velocity than the wc nozzle. The enthalpy probe calculations imply the assumption that the static pressure of t...
IEEE International Conference on Plasma Science, 2002
Summary form only given. HF plasma has been used for numerous applications. HF plasma of subsonic... more Summary form only given. HF plasma has been used for numerous applications. HF plasma of subsonic flow is used for densification and spheroidization of powders, thermal protection deposition and liquid and gaseous waste destruction. As for HF plasma supersonic flow, in spite of its less frequent use, its diagnostic is crucial in order to improve processes involving this type of
Une étude sur le diagnostic du jet de plasma haute fréquence (H.F.) supersonique est présentée da... more Une étude sur le diagnostic du jet de plasma haute fréquence (H.F.) supersonique est présentée dans ce mémoire. Pour réaliser cette étude, des instruments complémentaires de diagnostic dont certains ont une bonne résolution spatiale (mm) et d'autres ont une bonne résolution temporelle ([micromètre]) sont utilisés. Le premier instrument employé est la sonde enthalpique avec laquelle des profils d'enthalpie, de température, de vitesse et de nombre de Mach sont mesurés. Ces profils donnent lieu à une détermination sommaire de la structure supersonique du jet de plasma HF et de l'influence du type de buse sur ce dernier. Ensuite, le design de la sonde est modifié afin de tenter de mesurer une pression se rapprochant de la pression statique dans le jet de plasma. L'étude se poursuit avec un second instrument: une caméra haute vitesse permettant de visualiser le jet de plasma avec une bonne résolution temporelle ([micromètre]). Finalement, l'étude se termine avec le système optique Schlieren qui permet de découvrir des gradients de densité dans un milieu et c'est pour cela qu'il est utilisé afin de caractériser le jet supersonique de plasma."--Résumé abrégé par UMI
Plasma Sources Science and Technology, 2005
The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the re... more The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the results of its preliminary electrical and spectroscopic characterization are presented. A capacitively-coupled pulsed RF (13.56 MHz) helium plasma jet is formed in a converging confinement tube and O2 is injected downstream in the plasma afterglow region through a capillary electrode. With 1 SLM He, the APGD-t
Plasma Processes and Polymers, 2006
... Email: Valérie Léveillé (valerie.leveille1@mail.mcgill.ca). *Correspondence: Valérie Léveillé... more ... Email: Valérie Léveillé (valerie.leveille1@mail.mcgill.ca). *Correspondence: Valérie Léveillé, Department of Chemical Engineering, McGill University, 3610 University Street, Montréal (Québec), Canada, H3A 2B2. Fax: +1 514 398 6678. Publication History. ...
Measurement Science and Technology, 2006
The paper highlights and provides solutions to the difficulties encountered with electrical probe... more The paper highlights and provides solutions to the difficulties encountered with electrical probe measurements performed on a miniature, high capacitive impedance plasma device excited at 13.56 MHz. It is shown that a proper calibration of the phase angle between the circuit current and load voltage signals is required when commercial capacitive voltage probes (Tektronix P6139A and P5100 models) are used.
Pure and Applied Chemistry, 2006
The operating parameters of a miniature atmospheric pressure glow discharge torch (APGD-
Journal of Physics D: Applied Physics, 2006
A miniature atmospheric pressure glow discharge plasma torch was used to detach cells from a poly... more A miniature atmospheric pressure glow discharge plasma torch was used to detach cells from a polystyrene Petri dish. The detached cells were successfully transplanted to a second dish and a proliferation assay showed the transplanted cells continued to grow. Propidium iodide diffused into the cells, suggesting that the cell membrane had been permeabilized, yet the cells remained viable 24 h after treatment. In separate experiments, hydrophobic, bacteriological grade polystyrene Petri dishes were functionalized. The plasma treatment reduced the contact angle from 93 • to 35 • , and promoted cell adhesion. Two different torch nozzles, 500 µm and 150 µm in internal diameter, were used in the surface functionalization experiments. The width of the tracks functionalized by the torch, as visualized by cell adhesion, was approximately twice the inside diameter of the nozzle. These results indicate that the miniature plasma torch could be used in biological micropatterning, as it does not use chemicals like the present photolithographic techniques. Due to its small size and manouvrability, the torch also has the ability to pattern complex 3D surfaces.
The paper highlights and provides solutions to the difficulties encountered with electrical probe... more The paper highlights and provides solutions to the difficulties encountered with electrical probe measurements performed on a miniature, high capacitive impedance plasma device excited at 13.56 MHz. It is shown that a proper calibration of the phase angle between the circuit current and load voltage signals is required when commercial capacitive voltage probes (Tektronix P6139A and P5100 models) are used. A method to calculate the electrical characteristics of the plasma source and accounting for this calibration is described. The P6139A probe, which has the largest input capacitance and shortest cable length, introduced the smallest phase angle (−2 ± 1 • ), while the P5100 probe, which is used for higher input voltages and has a longer cable length, introduced a considerably larger phase angle (−34 ± 1 • ) for typical resistive loads. Simple circuit models are developed in an attempt to isolate the phase induced by the probe capacitance and cable length. The application of the proposed calibration to a miniature atmospheric pressure glow discharge source considerably reduced the error in the calculation of the power dissipated in the plasma device, though it remained relatively high (1 W ± 42%) due to the highly capacitive nature of the device.
The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the re... more The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the results of its preliminary electrical and spectroscopic characterization are presented. A capacitively-coupled pulsed RF (13.56 MHz) helium plasma jet is formed in a converging confinement tube and O 2 is injected downstream in the plasma afterglow region through a capillary electrode. With 1 SLM He, the APGD-t produced a non-thermal plasma jet of 500 µm-diameter and ≈2.5 mm-long at power levels ranging from 1 to 5 W. At ≈1 W, the gas temperature and He excitation temperature near the nozzle exit were ≈50˚C and slightly below 2000 K, respectively. The breakdown voltage in 1 SLM He is approximately 220 V pk-to-0 . Careful electric probe measurements and circuit analysis revealed the strong effect of the voltage probe on the total load impedance. The injection of 10 SCCM O 2 through the capillary electrode led to the transport of atomic O further downstream in the plasma jet and to a slight increase of the He excitation temperature without significant effects on the electrical properties and jet length. Alternatively, the addition of an equivalent amount of O 2 (1 v/v%) to the plasma-forming gas affected the electrical properties slightly, but led to a drastic contraction of the plasma jet. The atomic oxygen production and transport conditions provided by the APGD-t are promising for precise bio-applications such as the treatment of skin tissues and cells.
Plasma Processes and Polymers, 2006
Pure and Applied Chemistry, 2006
The operating parameters of a miniature atmospheric pressure glow discharge torch (APGD-t) are op... more The operating parameters of a miniature atmospheric pressure glow discharge torch (APGD-t) are optimized for the production of excited atomic oxygen, and the effect of the plasma jet on endothelial cells grown in Petri dishes is studied. We first demonstrate the importance of accounting for the effect of the voltage probe used to measure the electrical parameters of the torch on its ignition and operation characteristics. When operated with a main plasma gas flow rate of 1 SLM He and a power level of ~1 W, the torch shows an optimum in the production of excited atomic oxygen for a O 2 flow of ~3.5 SCCM injected downstream from the plasma-forming region through a capillary electrode (i.e., 0.35 v/v % O 2 /He). It is shown that endothelial cells are detached from the Petri dishes surface under the action of the optimized plasma jet and that this effect does not originate from heating and fluid shearing effects. It is postulated that the cell detachment is caused solely by plasma-induced biochemical processes taking place at the cell-substrate interface.
Thermal Spray 2003: Proceedings from the International Thermal Spray Conference
In this study, two complementary techniques of diagnostic are used to study the properties of a s... more In this study, two complementary techniques of diagnostic are used to study the properties of a supersonic HF plasma flow: namely, an enthalpy probe measurement and a flow visualization. A PL-35 induction plasma torch operating with three convergent-divergent Laval-type nozzles generates the plasma: a Mach 3.0 velocity water-cooled (wc) nozzle, a Mach 1.5 velocity wc nozzle and a Mach 2.45 velocity radiation-cooled (rc) nozzle. The plasma plate power is fixed at 20 kW and chamber pressure varies between 1 and 10 kPa. The plasma gas is argon and its flow is fixed at 60 slpm. The enthalpy probe profiles of local enthalpy and stagnation pressure are measured, from which, temperature, velocity and Mach number are obtained. The effect of nozzle design on plasma properties is investigated. The RC nozzle creates a plasma jet hotter with a steeper thermal profile and a higher mean velocity than the wc nozzle. The enthalpy probe calculations imply the assumption that the static pressure of t...
IEEE International Conference on Plasma Science, 2002
Summary form only given. HF plasma has been used for numerous applications. HF plasma of subsonic... more Summary form only given. HF plasma has been used for numerous applications. HF plasma of subsonic flow is used for densification and spheroidization of powders, thermal protection deposition and liquid and gaseous waste destruction. As for HF plasma supersonic flow, in spite of its less frequent use, its diagnostic is crucial in order to improve processes involving this type of
Une étude sur le diagnostic du jet de plasma haute fréquence (H.F.) supersonique est présentée da... more Une étude sur le diagnostic du jet de plasma haute fréquence (H.F.) supersonique est présentée dans ce mémoire. Pour réaliser cette étude, des instruments complémentaires de diagnostic dont certains ont une bonne résolution spatiale (mm) et d'autres ont une bonne résolution temporelle ([micromètre]) sont utilisés. Le premier instrument employé est la sonde enthalpique avec laquelle des profils d'enthalpie, de température, de vitesse et de nombre de Mach sont mesurés. Ces profils donnent lieu à une détermination sommaire de la structure supersonique du jet de plasma HF et de l'influence du type de buse sur ce dernier. Ensuite, le design de la sonde est modifié afin de tenter de mesurer une pression se rapprochant de la pression statique dans le jet de plasma. L'étude se poursuit avec un second instrument: une caméra haute vitesse permettant de visualiser le jet de plasma avec une bonne résolution temporelle ([micromètre]). Finalement, l'étude se termine avec le système optique Schlieren qui permet de découvrir des gradients de densité dans un milieu et c'est pour cela qu'il est utilisé afin de caractériser le jet supersonique de plasma."--Résumé abrégé par UMI
Plasma Sources Science and Technology, 2005
The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the re... more The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the results of its preliminary electrical and spectroscopic characterization are presented. A capacitively-coupled pulsed RF (13.56 MHz) helium plasma jet is formed in a converging confinement tube and O2 is injected downstream in the plasma afterglow region through a capillary electrode. With 1 SLM He, the APGD-t
Plasma Processes and Polymers, 2006
... Email: Valérie Léveillé (valerie.leveille1@mail.mcgill.ca). *Correspondence: Valérie Léveillé... more ... Email: Valérie Léveillé (valerie.leveille1@mail.mcgill.ca). *Correspondence: Valérie Léveillé, Department of Chemical Engineering, McGill University, 3610 University Street, Montréal (Québec), Canada, H3A 2B2. Fax: +1 514 398 6678. Publication History. ...
Measurement Science and Technology, 2006
The paper highlights and provides solutions to the difficulties encountered with electrical probe... more The paper highlights and provides solutions to the difficulties encountered with electrical probe measurements performed on a miniature, high capacitive impedance plasma device excited at 13.56 MHz. It is shown that a proper calibration of the phase angle between the circuit current and load voltage signals is required when commercial capacitive voltage probes (Tektronix P6139A and P5100 models) are used.
Pure and Applied Chemistry, 2006
The operating parameters of a miniature atmospheric pressure glow discharge torch (APGD-
Journal of Physics D: Applied Physics, 2006
A miniature atmospheric pressure glow discharge plasma torch was used to detach cells from a poly... more A miniature atmospheric pressure glow discharge plasma torch was used to detach cells from a polystyrene Petri dish. The detached cells were successfully transplanted to a second dish and a proliferation assay showed the transplanted cells continued to grow. Propidium iodide diffused into the cells, suggesting that the cell membrane had been permeabilized, yet the cells remained viable 24 h after treatment. In separate experiments, hydrophobic, bacteriological grade polystyrene Petri dishes were functionalized. The plasma treatment reduced the contact angle from 93 • to 35 • , and promoted cell adhesion. Two different torch nozzles, 500 µm and 150 µm in internal diameter, were used in the surface functionalization experiments. The width of the tracks functionalized by the torch, as visualized by cell adhesion, was approximately twice the inside diameter of the nozzle. These results indicate that the miniature plasma torch could be used in biological micropatterning, as it does not use chemicals like the present photolithographic techniques. Due to its small size and manouvrability, the torch also has the ability to pattern complex 3D surfaces.
The paper highlights and provides solutions to the difficulties encountered with electrical probe... more The paper highlights and provides solutions to the difficulties encountered with electrical probe measurements performed on a miniature, high capacitive impedance plasma device excited at 13.56 MHz. It is shown that a proper calibration of the phase angle between the circuit current and load voltage signals is required when commercial capacitive voltage probes (Tektronix P6139A and P5100 models) are used. A method to calculate the electrical characteristics of the plasma source and accounting for this calibration is described. The P6139A probe, which has the largest input capacitance and shortest cable length, introduced the smallest phase angle (−2 ± 1 • ), while the P5100 probe, which is used for higher input voltages and has a longer cable length, introduced a considerably larger phase angle (−34 ± 1 • ) for typical resistive loads. Simple circuit models are developed in an attempt to isolate the phase induced by the probe capacitance and cable length. The application of the proposed calibration to a miniature atmospheric pressure glow discharge source considerably reduced the error in the calculation of the power dissipated in the plasma device, though it remained relatively high (1 W ± 42%) due to the highly capacitive nature of the device.
The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the re... more The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the results of its preliminary electrical and spectroscopic characterization are presented. A capacitively-coupled pulsed RF (13.56 MHz) helium plasma jet is formed in a converging confinement tube and O 2 is injected downstream in the plasma afterglow region through a capillary electrode. With 1 SLM He, the APGD-t produced a non-thermal plasma jet of 500 µm-diameter and ≈2.5 mm-long at power levels ranging from 1 to 5 W. At ≈1 W, the gas temperature and He excitation temperature near the nozzle exit were ≈50˚C and slightly below 2000 K, respectively. The breakdown voltage in 1 SLM He is approximately 220 V pk-to-0 . Careful electric probe measurements and circuit analysis revealed the strong effect of the voltage probe on the total load impedance. The injection of 10 SCCM O 2 through the capillary electrode led to the transport of atomic O further downstream in the plasma jet and to a slight increase of the He excitation temperature without significant effects on the electrical properties and jet length. Alternatively, the addition of an equivalent amount of O 2 (1 v/v%) to the plasma-forming gas affected the electrical properties slightly, but led to a drastic contraction of the plasma jet. The atomic oxygen production and transport conditions provided by the APGD-t are promising for precise bio-applications such as the treatment of skin tissues and cells.
Plasma Processes and Polymers, 2006
Pure and Applied Chemistry, 2006
The operating parameters of a miniature atmospheric pressure glow discharge torch (APGD-t) are op... more The operating parameters of a miniature atmospheric pressure glow discharge torch (APGD-t) are optimized for the production of excited atomic oxygen, and the effect of the plasma jet on endothelial cells grown in Petri dishes is studied. We first demonstrate the importance of accounting for the effect of the voltage probe used to measure the electrical parameters of the torch on its ignition and operation characteristics. When operated with a main plasma gas flow rate of 1 SLM He and a power level of ~1 W, the torch shows an optimum in the production of excited atomic oxygen for a O 2 flow of ~3.5 SCCM injected downstream from the plasma-forming region through a capillary electrode (i.e., 0.35 v/v % O 2 /He). It is shown that endothelial cells are detached from the Petri dishes surface under the action of the optimized plasma jet and that this effect does not originate from heating and fluid shearing effects. It is postulated that the cell detachment is caused solely by plasma-induced biochemical processes taking place at the cell-substrate interface.