PhD positions

Division of Environmental Physics, Faculty of Mathematics, Physics and Informatics of Comenius University in Bratislava is currently seeking highly qualified applicants for 4-year doctoral program starting in September 2024.

PhD position 1: Use of cold plasma and photocatalytic effect in indoor air decontamination
under supervision of Prof. Zdenko Machala
 

Keywords: Cold plasma, photocatalysis, UV, indoor air, decontamination

Annotation:
The impact of humans on closed air environment (e.g., ambulances, waiting rooms, aircraft cabins, spacecraft manned modules) results in a contaminated atmosphere with viruses, bacteria, particulate matter, and chemical pollutants. This indoor contamination has far-reaching effects on the human health, and traditional filtration-based air cleaning technologies are often inadequate in mitigating the issue. Thus, to address this pressing environmental and health issue, a new approach based on a combination if cold air plasma with photocatalytic effect is proposed. Cold atmospheric plasmas generated by electrical discharges are efficient sources of reactive oxygen and nitrogen species. They produce strong oxidative environment and induce antimicrobial and cytotoxic effects in cells and tissues. Multiple applications based on cold plasmas are being developed, such as water cleaning, bio-decontamination and sterilization, surface decontamination with impact in dentistry, disinfection, wound healing, and potential cancer therapies, or stimulation of germination and plant growth in agriculture. The plasma effects are often enhanced by humidity or water aerosols. Plasma interactions with liquids is a novel way/approach to research, and it greatly contributes to a more complex understanding of the interaction of cold plasmas with complex biological systems.

Objectives:
The key objectives are investigations of the use of cold plasma and and photocatalytic effect in indoor air decontamination.
The particular objectives are:

  • Experimental investigations of electrical parameters of various dielectric barrier setups in (contaminated) airflows
  • FTIR and UV-vis spectroscopic measurements of gaseous contaminants (e.g. formaldehyde) and reactive species (ozone, NOx)
  • Testing the performance of the DBD setup alone and in combination with UV-photocatalyst (TiO2 layer) against selected chemical pollutants in a closed-loop and single-pass setting
  • Testing the performance of the DBD setup alone and in combination with UV-photocatalyst (TiO2 layer) against selected bio-aerosols contaminated with bacteria/yeasts
Note:
The potential candidate should be an enthusiastic person with a solid knowledge and experience with experimental physics/spectroscopy/plasma physics/biophysics/microbiology. He/she will work in the dynamic multi-disciplinary research group conducting studies at the frontiers of cold plasma science and environmental technologies. His/her work will be related to the European Space Agency (ESA) project CLEAN (if funded). The collaboration will be between Environmental Physics group of Comenius University Bratislava, Mechanical Engineering faculty of TUKE, SME IQ Capital, and international partner Thales Alenia Space Italy. Previous practical experience in working with non-thermal plasma and air decontamination will be welcome. Laboratory research experience is required. The minimal requirements include a completed Master level degree in the intended area of study or a closely related area. The topic is also related to our project of the Slovak Research and Development Agency (APVV): Plasma-liquid interactions and the effects/applications of plasma activated liquids in medicine and agriculture.

 
PhD position 2: Plant growth promotion by foliar and hydroponic application of plasma activated water
under supervision of Assoc.Prof. Karol Hensel
 

Objectives:
The objective of the thesis would be:

  • Investigation of gaseous discharges and cold plasmas, their interaction with water and formation of plasma activated water (PAW).
  • Physical and chemical analysis of PAWs - pH, ORP, concentration of reactive (e.g. H2O2, NO2, NO3-, NH4+.)
  • Foliar application of PAW and also plasma activated organic fertilizers to plants
  • Hydroponic cultivations of plants in PAW and later its optimization.
  • Biological analysis of the effect of PAW on plant growth and quality including growth parameters, concentration of photosynthetic pigments, activity and in situ analysis of antioxidant enzymes, changes of the root lignification, and radicals (H2O2 and O2•¯) visualisation.
  • Monitoring the plant response to stress factors (heavy metals, radiation, drought) in the presence of PAW.
Note:
The potential candidate should be an enthusiastic person with a solid knowledge and experience either in physics of plasmas, or experience in plant biology, biology or biotechnology.

PhD position 3: Inactivation pathways induced in bacteria and biofilms by cold atmospheric plasma
under supervision of Assoc.Prof. Karol Hensel
 

Annotation:
Cold atmospheric plasma shows its potential as it presents itself as a new effective and affordable method capable of inactivating bacteria, biofilms, moulds and even viruses. It is believed that the effects of plasma are mediated mainly by the action of reactive oxygen and nitrogen species promoted by the influence of electric fields and UV radiation.

Objectives:
Investigating the inactivation mechanisms of different bacterial strains and biofilms induced by pulsed streamer corona discharge and self-pulsating transient spark discharge in atmospheric air. The discharges will be applied directly to planktonic bacteria in water and in saline and to single and mixed species bacterial biofilms on various surfaces. Bacterial viability will be investigated, metabolic activity, cell membrane integrity, cell morphology, accumulation of intracellular ROS as well as biofilm biomass, its damage and removal of its layers as well as suppression of intracellular metabolism. Physical and chemical properties of solutions, e.g. pH, conductivity, oxidative reduction potential and production of reactive substances in liquid solutions, as well as in the gas phase, will be monitored and correlated with bactericidal efficacy.

Note:
The potential candidate should be an enthusiastic person with a solid knowledge and experience either in physics of plasmas, or experience in biology or biotechnology.

Eligibility and requirements
The minimal requirements include a completed Master level degree in the intended area of study or a closely related area. Applicants are required to submit following documents by en e-mail to a potential supervisor:

  • CV with the list of publications
  • brief motivation letter
  • proof of receiving of the MSc degree (e.g. scan of the diploma)

Application and evaluation process
The deadline for application is April 24, 2024. Received applications will be briefly evaluated and the best applicants will be selected for a pre-interview. If the pre-interview is successful the applicants will be approved to enroll in the main application process at the Faculty level with a deadline of April 30. The main faculty interview will be held in the middle of June.

PhD study
A candidate who will pass the faculty interview will be accepted for a PhD studies starting from September 2024. A standard duration of the PhD program is 4 years. Every year the student's activity and achievements is evaluated. If the evaluation is successful the student is allowed to pass to the next year of the study.

Scholarship and accommodation]
The student is entitled to receive a tax-free monthly scholarship of 1025 EUR, further increased to 1194 EUR after passing qualification exams. Accommodation in a student dormitory is guaranteed. Additional funds are often available to the most successful and productive students.

Additional details on PhD studies at Comenius University
link 1
link 2

Contact
Prof. Zdenko Machala (machala@fmph.uniba.sk)
Assoc. Prof. Karol Hensel (hensel@fmph.uniba.sk)