One postdoctoral position is open immediately in the Plasma Research Laboratory at Clarkson University. The position is linked to a project funded through the New York State Pollution Prevention Institute to investigate electrical discharge plasma treatment on inactivation of microorganisms in liquid foods. The goal is to optimize and scale-up an energy-efficient plasma reactor that achieves >5 log reduction of pathogenic and other spoilage microorganisms in milk and fruit juices while preserving nutritional and organoleptic properties of the treated food. Research objectives of this project include:

• Optimization of the liquid plasma reactor
• Reactor scale up to increase the treatment capacity
• Assessment of treatment of raw milk, apple cider, apple, strawberry, raspberry, grape, and blueberry fruit juices contaminated with bacteria, yeast, and mold, and
• Examination of the physicochemical and organoleptic properties of the treated food.

This position requires a candidate with a strong work ethic, ability to work in a team, and excellent written and communication skills. The candidate must have (or be about to obtain) a PhD or equivalent in a relevant engineering or science field and publication record. Technical experience in electrical discharge plasmas, disinfection technologies, food science, or microbial analyses is advantageous.

Please address all inquiries and submit your application materials electronically including a cover letter, CV, three personal references, and two sample publications to:

Dr. Selma Mededovic Thagard, Assistant Professor, Chemical and Biomolecular Engineering, Clarkson University (smededov@clarkson.edu)

Selma received funding from the New York State Pollution Prevention Institute for studying the effect of liquid plasmas on inactivation of pathogens and spoilage organisms in fruit juices

Josh, Xiangru, and Selma will be giving talks at the International Symposium on Non-Thermal/Thermal Plasma Pollution Control Technology and Sustainable Energy (ISNTP-9) in Dalian, China this June. The presentations will be posted to Research Gate after the conference.

Lauren, a ChemE undergraduate who will be joining our lab this summer received the National Grid scholarship for conducting research on electrical discharge plasmas. Congratulations!

Group Photo, September 2013

Name
Designer

Principal Investigator

Teammember Selma Mededovic Thagard
Selma Mededovic Thagard
Assistant Professor

Dr. Thagard’s research interests lie in applications of electrical discharge plasmas for  drinking and wastewater remediation, exhaust gas cleaning, hydrogen production from renewable sources, and food sterilization as well as in the mathematical modeling of such systems.

PROFESSIONAL APPOINTMENTS

  1. Assistant Professor (August 2010-Present)
    Department of Chemical  and Biomolecular Engineering, Clarkson University, Potsdam, New York.
  2. Postdoctoral Researcher (August 2009-July 2010)
    Department of Chemistry, Colorado State University, Fort Collins, Colorado.
  3. Postdoctoral Researcher (August 2007-April 2009)
    Department of Ecological Engineering, Toyohashi University of Technology, Toyohashi, Japan.
  4. Graduate Research Assistant (August 2003-June 2007)
    Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida.
  5. Research and Development Engineer (January 2002-May 2003), Katran, Zagreb, Croatia.

EDUCATION

  • Ph.D in Chemical Engineering (August 2003-June 2007)
    Department of Chemical and Biomedical Engineering, Florida State University, Tallahassee, Florida.
    Dissertation Title: Chemical Processes in Aqueous Phase Pulsed Electrical Discharges: Fundamental Mechanisms and Applications to Organic Compound Degradation. Dissertation advisor: Bruce R. Locke.
  • BS Chemical Engineering (September 1997-May 2002)
    Faculty of Chemical Engineering and Technology, University of Zagreb, Zagreb, Croatia.

Current Graduate Students

 

Teammember Gunnar Stratton
Gunnar Stratton
Graduate Student
Gunnar is working on plasma reactor scale up for drinking water treatment.

 

Teammember Josh Franclemont
Josh Franclemont
Graduate Student
Josh is studying the effects of bulk liquid composition on the properties of liquid-phase electrical discharge plasmas. He is also working on the optimization of the production of hydrogen-rich gas from glycerol and biodiesel from vegetable oil.

 

Teammember Xiangru Fan
Xiangru Fan
Graduate Student

 

Teammember Tomislava Vukusic
Tomislava Vukusic
Graduate Student
Tomislava is working on the implementation of liquid-phase electrical discharge plasmas in sterilization of fruit juices and milk.

Current Summer Undergraduate Students 

 

Teammember Sean Eustace
Sean Eustace
Undergraduate Student

 

Teammember Kate Price
Kate Price
Undergraduate Student

 

Teammember Abby Lueber
Abby Lueber
Undergraduate Student

Previous Graduate Students 

 

Teammember Make Geng
Make Geng
MS Student
Make worked on the ultrasonic degradation of dyes in aqueous solutions and the fundamental processes in electrical discharges. Make completed his studies, graduating in May 2012.

Previous Summer Undergraduate Students 

 

Teammember Kevin Fischer
Kevin Fischer
Honors Student

 

Teammember Tom Jacobsen
Tom Jacobsen
Honors Student

 

Teammember Tessora Young
Tessora Young
REU Student
Summer of 2011, University of Utah

Journal Publications

  • Joshua Franclemont and Selma Mededovic Thagard, “Pulsed electrical discharges in water: Can non-volatile compounds diffuse into the plasma channel?”, DOI 10.1007/s11090-014-9550-4, Plasma Chemistry and Plasma Processing, 2014
  • Parag R. Gogate, Selma Mededovic Thagard, Jamar Blackmon,Robert Cathey, and George Chapas, “Hybrid Reactor Based on Combined Cavitation and Ozonation: From Concept to Practical Reality”, Ultrasonics Sonochemistry, 21, pp.590-598, 2014
  • Verica Batur, Selma Mededovic Thagard, Anet Režek Jambrak, Tomislava Vukušić and Zoran Herceg , “Effect of Tribomechanical Micronisation and Activation Treatment on Textural and Thermophysical Properties of Wheat and Potato Starch Gels”, Food Technology and Biotechnology, 51, pp.278-283, 2013
  • Tessora Young, Make Geng, Lin Lin and Selma Mededovic Thagard, “Oxidative Degradation of Bisphenol A: A comparison between Fenton reagent, UV, UV/H2O2 and ultrasound”, Journal of Advanced Oxidation Technologies, 16, pp.89-101, 2013
  • Ravindra P. Joshi and Selma Mededovic Thagard, “Streamer-like electrical discharges in water: Part II. Environmental applications”, Plasma Chemistry and Plasma Processing, 33, pp.17-49, 2013
  • Ravindra P. Joshi and Selma Mededovic Thagard, “Streamer-like electrical discharges in water: Part I. Fundamental mechanisms”, Plasma Chemistry and Plasma Processing,33, pp.1-15,2013
  • Make Geng and Selma Mededovic Thagard, “The effects of externally applied pressure on the ultrasonic degradation of Rhodamine B”, Ultrasonics Sonochemistry, 20, pp.618–625, 2013
  • Bruce R. Locke and Selma Mededovic Thagard, “Analysis and Review of Chemical Reactions and Transport Processes in Pulsed Electrical Discharge Plasma Formed Directly in Liquid Water”, Plasma Chemistry and Plasma Processing, 32, pp.875-917, 2012
  • Selma Mededovic Thagard, Graciela Prieto, Kazunori Takashima and Akira Mizuno, “Identification of Gas Phase Byproducts Formed During Electrical Discharges in Liquid Fuels”, IEEE Transactions on Plasma Science, 40, pp.2016-2111, 2012
  • Kevin B. Fisher and Selma Mededovic Thagard, “Transformation of Organic Solvents into Carbon-based Materials by Liquid-Phase Plasmas”, Plasma Chemistry and Plasma Processing, 32, pp.919-931, 2012
  • Zoran Herceg, Anet Rezek Jambrak, Vesna Lelas and Selma Mededovic Thagard, “Application of High Intensity Ultrasound Treatment on Amount of Staphylococcus aureus and Escherichia coli in Milk”, Food Technology and Biotechnology, 50, pp. 46-52, 2012
  • Selma Mededovic Thagard, Yohei Kinoshita, Hiromitsu Ikeda, Kazunori Takashima, Shinji Katsura, and Akira Mizuno, “NO3- Reduction for NOx Removal Using Wet-Type Plasma Reactor”, IEEE Transactions on Industry Applications, 46, pp. 2165-2171, 2010
  • Selma Mededovic Thagard, Ellen R. Fisher, Graciela Prieto, Kazunori Takashima and Akira Mizuno, “Production of Hydrogen from Sugar by a Liquid Phase Electrical Discharge”, International Journal of Plasma Environmental Science and Technology, 4, pp. 163-168, 2010
  • Selma Mededovic Thagard, Kazunori Takashima and Akira Mizuno, “Electrical Discharge in Relatively Polar Organic Liquids”, Plasma Processes and Polymers, 6, pp. 741-750, 2009
  • Selma Mededovic Thagard, Kazunori Takashima and Akira Mizuno, “Chemistry of the Positive and Negative Electrical Discharges Formed in Liquid Water and Above a Gas-Liquid Interface”, Plasma Chemistry and Plasma Processing, 29, pp.455-473, 2009
  • Selma Mededovic Thagard, Kazunori Takashima and Akira Mizuno, “Plasma Chemistry in Pulsed Electrical Discharge in Liquid”, Transaction of the Material Research Society of Japan, 34, pp. 257-262, 2009
  • Selma Mededovic Thagard, Adrian Mihailcioiu, Kazunori Takashima and Akira Mizuno, “Analysis of the Byproducts in the Ammonia Production from Urea by Dielectric Barrier Discharge”, IEEE Transactions on Plasma Science, 37, pp. 444-448, 2009
  • Bruce R. Locke and Selma Mededovic Thagard, “Analysis of Chemical Reactions in Gliding-Arc Reactors With Water-Spray Into Flowing Oxygen”, IEEE Transactions on Plasma Science, 37, pp. 494-501, 2009
  • Selma Mededovic Thagard, Kazunori Takashima and Akira Mizuno, “Decolorization of Indigo Carmine Dye by Spark Discharge in Water”, International Journal of Plasma Environmental Science and Technology, 2, pp. 56-66, 2008
  • Selma Mededovic and Bruce R. Locke, “Primary Chemical Reactions in Pulsed Electrical Discharge Channels in Water”, Journal of Physics D: Applied Physics, 40, pp. 7734-7746, 2007
  • Selma Mededovic, Wright C. Finney and Bruce R. Locke, “Electrical Discharges in Mixtures of Light and Heavy Water”, Plasma Processes and Polymers, 56, pp. 76-83, 2007
  • Selma Mededovic and Bruce R. Locke, “Side Chain Degradation of Atrazine by Pulsed Electrical Discharge in Water”, Industrial and Engineering Chemistry Research, 46, pp. 2702-2709, 2007
  • Selma Mededovic and Bruce R. Locke, “Aqueous Phase Mineralization of s-Triazine Using a Pulsed Electrical Discharge”, International Journal of Plasma Environmental Science and Technology, 1, pp. 2-9, 2007
  • Selma Mededovic and Bruce R Locke, “The Role of Platinum as the High Voltage Electrode in the Enhancement of Fenton’s Reaction in Liquid Phase Pulsed Electrical Discharge”, Applied Catalysis B: Environmental, 72, pp. 342-350, 2006
  • Selma Mededovic and Bruce R Locke, “Platinum Catalyzed Decomposition of Hydrogen Peroxide in Aqueous-Phase Pulsed Corona Electrical Discharge”, Applied Catalysis B: Environmental, 67, pp. 149-159, 2006
Conference Proceedings
  • Selma Mededovic and Bruce R. Locke, “The Role of Platinum High Voltage Electrode in the Enhancement of Fenton’s Reaction in Pulsed Corona Aqueous Phase Discharge, 5th International Symposium on Non-Thermal Plasma Technology for Pollution Control and Sustainable Energy Development, June 19-23, 2006, Ile d’Oleron, France
Presentations
  • Christopher Bellona, Fei Dai, Joshua Franclemont, Thomas Holsen, Gunnar Stratton, and Selma Mededovic Thagard, “Pursuing a Viable Plasma-Based Water Treatment Process: Identifying Treatment Limitations and Investigating the Effect of Reactor Design on the Degradation of Phenytoin”, The 19th International Conference on Advanced Oxidation Technologies for Treatment of Water, Air and Soil (AOTs-19), San Diego, California, USA November 17-21, 2013
  • Selma Mededovic Thagard, Christopher Bellona, Fei Dai, Joshua Franclemont, Thomas Holsen, Gunnar Stratton and Chao Zhang, “Pursuing a Viable Plasma-Based Water Treatment Process: Identifying Transport Limitations and Investigating the Effect of Reactor Design On the Degradation of Bisphenol A”, AIChE Annual Meeting, San Francisco, California, USA, November 3-8, 2013
  • Joshua Franclemont, Gunnar Stratton and Selma Mededovic Thagard, “Electrical Discharges Directly in Liquid Glycerol for the Production of Hydrogen”, IEEE Pulsed Power and Plasma Science, San Francisco, California, USA, June 16-21, 2013
  • Joshua Franclemont and Selma Mededovic Thagard, “Electrical discharges in water: which molecules can diffuse inside the plasma channels?”, Department of Chemical and Biomolecular Engineering, Clarkson University, Graduate Seminar, April 11, 2013
  • Joshua Franclemont and Selma Mededovic Thagard, “Mathematical Modeling of Electrical Discharges in Liquid Water: The Chemistry Inside the Plasma Channel”, AIChE Annual Meeting, Pittsburgh, Pennsylvania, USA, October 28-November 2, 2012
  • Selma Mededovic Thagard, “Chemical Properties and Degradation Efficiency of Radio-Frequency Plasmas in Water”, AIChE Annual Meeting, Minneapolis, Minnesota, USA, October 16-21, 2011
  • Selma Mededovic Thagard, “Electrical Discharges in Organic Liquids for Material Sythesis”, CAMP Annual Spring Symposium, Fairport, New York, March 6-7, 2011
  • Selma Mededovic Thagard, Kazunori Takashima, Hirofumi Takikawa and Akira Mizuno, “Production of Diamond-Like Carbon (DLC) Coatings by the Liquid-Phase Electrical Discharge”, AIChE Annual Meeting, Salt Lake City, Utah, USA, November 7-12, 2010
  • Selma Mededovic Thagard, “Electrical Discharges in Liquids: Fundamental Studies and Applications”, Invited talk, Tennessee Tech, Oct 26th, 2010
  • Selma Mededovic Thagard, Ellen R. Fisher, Graciela Prieto, Kazunori Takashima and Akira Mizuno, “The Production of Hydrogen by the Electrical Discharge in Sugar Solution”, AIChE Spring National Meeting, San Antonio, Texas, USA, March 21-25, 2010
  • Graciela Prieto, Oscar Prieto, Carlos R. Gay, Selma Mededovic Thagard, Ellen R. Fisher, Kazunori Takashima and Akira Mizuno, “Hydrogen Production from Residual Heavy Oil”, AIChE Spring National Meeting, San Antonio, Texas, USA, March 21-25, 2010
  • Selma Mededovic Thagard, Graciela Prieto, Kazunori Takashima and Akira Mizuno, “Electrical Discharge in Liquid Ethanol: By-products Identification”, Japanese Institute of Electrostatics, Symposium, Tokyo, Japan, March 9-11, 2009
  • Selma Mededovic Thagard, Kazunori Takashima and Akira Mizuno, “Plasma Chemistry in Pulsed Electrical Discharge in Liquid”, Invited talk, IUMRS-ICA International Conference, Nagoya, Japan, December 9-13, 2008
  • Selma Mededovic Thagard, Kazunori Takashima and Akira Mizuno, “The Chemistry of Ammonium and Nitrate Ions in an Electrical Discharge”, International Workshop on Electrostatics, Ishigaki, Japan, November 12-15, 2008
  • Selma Mededovic Thagard, Kazunori Takashima and Akira Mizuno, “Comparison of the Positive and Negative Electrical Discharge in Water”, International Electrostatics Symposium, Okinawa, Japan, November 9-12, 2008
  • Selma Mededovic Thagard, Kazunori Takashima, Hirofumi Takikawa and Akira Mizuno, “Production of Diamond-Like Carbon Coatings by the Electrical Discharge in Different Organic Solvents”, 6th International Symposium on Non-Thermal Plasma, Taipei, Taiwan, May 12-16, 2008
  • Selma Mededovic and Bruce R. Locke, “The Role of Platinum High Voltage Electrode in the Enhancement of Fenton’s Reaction in Pulsed Corona Aqueous Phase Discharge”, 5th International Symposium on Non-Thermal Plasma, Oleron Island, France, June 19-23, 2006

 

Presentations (As Contributor)
  • Christopher Bellona, Selma Mededovic Thagard Thomas Holsen, and Eric Dickenson, “Integration of Filtration and Advanced Oxidation: Development of a Liquid-Phase Plasma Reactor: ICOSSE ’13 – 3rd International Congress on Sustainability Science & Engineering Cincinnati, OH, August 11 2013
  • Parag R. Gogate, Dennis McGuire, Selma Mededovic Thagard, Robert Cathey, J. Blackmon, and George Chapas, “Application of Ozonix Technology for Treatment of Wastewater and Intensified Processing in Coal Mining”, The 19th International Conference on Advanced Oxidation Technologies for Treatment of Water, Air and Soil (AOTs-19), San Diego, California, USA November 17-21, 2013
  • Bruce R. Locke and Selma Mededovic Thagard, “Chemical Reaction Analysis of the Formation of Hydrogen Peroxide and Hydrogen in Water-Spray Gliding Arc Reactors”, 35th IEEE International Conference on Plasma Science, Karlshrue, Germany, June 15-19, 2008
  • Adrian Mihailcioiu, Selma Mededovic Thagard, Kazunori Takashima and Akira Mizuno, ”Ammonia Generation From Solid Urea in Needle Array DBD Reactor”, Symposium of the Institute of Electrostatics Japan, September 18th, Kyoto, Japan, 2008
  • Mayank Sahni, Frank Holzer, Selma Mededovic, Wright C. Finney and Bruce R. Locke, “Analysis of Reactive Species Formation in High Voltage Electrical Discharges in Gas-Liquid Systems”, 4th Asia Pacific International Symposium on Basics and Applications of Plasma Science and Technology, Yunlin, Taiwan, December 12-14, 2005
Current Projects

Direct-In-Liquid Electrical Discharge for the Production of Hydrogen-Rich Gas CBET Award #1336385

Manufacturing of hydrogen from hydrocarbons is needed for a variety of applications, especially for the production of hydrogen-rich gas for fuel cell powered vehicles and plasma treatment of exhaust gas. Compared to other reforming technologies, electrical discharge plasmas provide several advantages including fast response time, durability, compactness, low weight, and high conversion efficiencies. However, to maximize the conversion of hydrocarbons and increase the byproduct selectivity, it is important to elucidate chemical reaction mechanisms and develop complete reaction schemes.

This project investigates the fundamental chemical process occurring during plasma-assisted reforming of liquid hydrocarbons and alcohols using direct-in-liquid pulsed streamer-like electrical discharges. Due to the relatively unexplored field of plasma-chemical reactions in liquid plasmas, and especially in organic liquids, the focus is on elucidating chemical pathways responsible for the formation of hydrogen, short-chained hydrocarbons and syngas during direct reforming of liquid fuels, reforming in the presence of water (termed water-assisted reforming), and reforming in the presence of air (oxidative reforming). It is expected that the unique combination of the experimental approach coupled to mathematical modeling and plasma imaging will lead to new insights and novel means of analyzing liquid plasmas.

The experimental approach will use radical scavenging techniques, plasma spectroscopy, as well as deuterated and isotopically labeled solvents to elucidate chemical reactions responsible for the formation of stable gaseous and liquid byproducts. The major hypothesis underlying the research is that in the absence of oxidants, the main decomposition byproducts of <C8 hydrocarbons and aromatic compounds will be short-chained hydrocarbons (<C4) and hydrogen. Hydrocarbons with >C8 will also produce alkanes with five or more carbon atoms. The presence of water and air will scavenge carbon atoms in plasma, lower the concentrations of light hydrocarbons, and increase the yield of CO (and possibly CO2). Experiments will first be conducted in simple fuel surrogates (e.g. parrafins, toluene, cyclohexane, etc.) followed by electrical discharges in real fuels (diesel, gasoline and kerosene).

Chemical kinetic models for fuels are a critical part of engine models. Unfortunately, increases in engine efficiency and decreases in engine emissions are being inhibited by an inadequate ability to simulate in-cylinder combustion and emission formation processes. To address this need and predict experimentally measured concentrations of stable byproducts, kinetic models for an electrical discharge in ethanol and in iso-octane will also be developed.

Imaging studies will be performed in order to characterize the discharge and its growth as a function of several parameters and, in particular, electrode polarity and molecular structure of the starting liquid. The mentioned techniques include fast optical imaging of the discharge, schlieren and shadowgraphic imaging of the discharge, and interferometry. The results of these measurements will yield valuable information about the streamer velocity, shock velocity branching, pressure in front of and behind the shock, plasma volume and possible electron density, all of which will be used to advance the understanding of the chemistry behind the discharge interaction with the fuel.

Production of biodiesel using liquid-phase electrical discharge plasmas BRIGE Award #1125592

Over the past ten years, the PI has studied the fundamental phenomena that occur during  electrical discharges in water and strived to expand the applications of liquid-phase plasmas to mediums other than water. She has demonstrated that an electrical discharge in dimethyl sulfoxide yields diamondlike carbon and that discharges in methanol and sucrose solutions yield hydrogen gas and ethanol, respectively. More recently, she discovered that within thirty minutes of plasma treatment, the viscosity of vegetable oil is reduced by about sixty percent. Because this later result could be important in the area of biodiesel (alkyl ester) production, the PI believes it must be explored further. Thus, the main goal of this proposal is to investigate and assess electrical discharges as a novel technology for the production of biodiesel and to study the fundamental chemistry of plasmas in oils. The first objective will be achieved by conducting electrical discharges in different vegetable oils (sunflower oil, palm oil and coconut oil) with or without additives (methanol, glycerol and sucrose), identifying reaction by-products and characterizing physical properties of the liquids after the discharge. In order to elucidate and categorize chemical processes inside the plasma and thus achieve the second objective, it is critical to examine the nature of chemical reactions. There has always been a suspicion that chemical reactions in plasmas are not driven purely by the electron impact dissociation but also, because of the high plasma temperatures, the pyrolysis. Thus, the development of a mathematical model to predict the plasma temperature will assist in answering fundamental questions regarding the types of chemical reactions in plasma and facilitate the understanding of the reaction pathways for the conversion of vegetable oil into biodiesel.

Membrane liquid phase plasma reactor

The main objective of this study is to engineer, develop and demonstrate an innovative water treatment technology that could potentially replace conventional water treatment unit processes for small water treatment systems. To this end, the PIs propose to integrate membrane technology (i.e., ceramic NF, UF or MF) with electrical discharge plasma generated via a novel reticulated vitreous carbon (RVC) electrode material. The reasons for the integration of these two processes are four-fold: (1) the novel RVC electrode material will significantly improve the efficiency and longevity of the electrical discharge; (2) the membrane process protects the porous electrode material from clogging and removes constituents targeted in conventional water treatment processes and that reduce the effectiveness of the AOP; (3) both the membrane and electrical discharge remove pathogens; and (4) electrical discharge is effective for the destruction of a wide variety of organic contaminants and contaminant precursors.

A tiered approach will be undertaken to achieve the overall project goal of demonstrating the integrated membrane/plasma process as an innovative, affordable, sustainable and effective treatment technology for small treatment systems. The team will first use a regimented approach to carefully select contaminants to investigate and evaluate the plasma process. Fundamental bench-scale studies will then be undertaken to investigate and optimize the plasma and membrane systems as individual and integrated processes. Findings from fundamental studies will be used to develop a scalable engineered membrane/plasma process that will be tested under carefully controlled conditions. Finally, long-term testing will be conducted with the developed system at small treatment systems to fully demonstrate the scalable membrane/plasma system.

The successful development of this process will result in a technology that is scalable, robust, requires minimal chemical input, has a small foot-print, and achieves a finished water quality better than treatment systems that require multiple technologies. The developed process will have unique treatment capabilities (i.e., targets both suspended and dissolved constituents) enabling the production of high-quality water from impaired sources, which will foster water recycling, a decreased reliance on imported water, and more efficient management of water supplies.

Drop us a line

ErrorPlease check your entries!

Office

Location: CAMP 243
Mailing Address: Department of Chemical and Biomolecular Engineering, Box 5705, 8 Clarkson Avenue, Potsdam, NY 13699
Ph#: 315-268-4423
Fax: 315-268-6654
Email: smededov@clarkson.edu

Laboratory

Location: CAMP 245 & CAMP 248
Ph#: 315-268-2124

ToTop