Mohamed Mokhtar Saad Fahim Hefny

22/02/2023

https://www.nature.com/articles/s41598-023-29774-8

Mohamed Mokhtar Saad Fahim Hefny

14/06/2022

https://www.nature.com/articles/s41598-022-13444-2

Mohamed Mokhtar Saad Fahim Hefny

02/06/2022

https://www.mdpi.com/2073-8994/14/6/1146

Mohamed Mokhtar Saad Fahim Hefny

03/06/2021

https://www.mdpi.com/2504-3110/5/2/51

Mohamed Mokhtar Saad Fahim Hefny

12/04/2021

https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/slct.202004716

Mohamed Mokhtar Saad Fahim Hefny

David Nečas, Lenka Zajíčková, and Jan Benedikt

01/03/2019

A remote microscale atmospheric pressure plasma jet with a He/O2 gas mixture is used to etch a hydrogenated amorphous carbon layer. The etched profiles are measured by means of imaging spectroscopic reflectometry, a powerful technique providing a 2D map of the film thickness (etched profile) and also film properties. Additionally, the 2D axially symmetric fluid model of the gas flow and species transport combined with the basic kinetic model of the reaction of O atoms with O2 molecules has been solved to study the transport and surface reactivity of O atoms. The model provides a spatially resolved and surface-integrated O atom loss rate at the surface. The situation with convection-dominated species transport and fast recombination reactions of O atoms in the volume leads to a strong dependence of the etched profile on the O2 admixture and O atom surface loss probability β. By comparing etched profiles with the simulation results, the O atom surface reaction probability of β = 0.2%–0.6% could be estimated. The modeled O atom loss rate at the surface was always higher and with the same trend as the etching rate, corroborating that O atoms are the main etching species. The presented data and simulation results show that the fastest surface-integrated etching rate is achieved not under conditions with the highest O density on the jet axis, but at lower O2 admixtures due to reduced recombination losses in the gas phase.

Mohamed Mokhtar Saad Fahim Hefny

19/04/2018

https://pubs.rsc.org/en/content/articlelanding/2018/cp/c8cp00197a

Mohamed Mokhtar Saad Fahim Hefny

J. Benedikt, A. Shaw, B. R. Buckley, F. Iza, S. Schäkermannf and J. Bandow

01/04/2018

Non-equilibrium radio-frequency driven atmospheric-pressure plasma in He/0.6%O2 gas mixture has been used to study the reaction mechanism of plasma-generated oxygen atoms in aqueous solutions. The effluent from the plasma source operated with standard and 18O-labeled O2 gas was used to treat water in the presence of phenol as a chemical probe. Comparing the mass spectrometry and gas chromatography-mass spectrometry data of the solutions treated with plasma under normal and labeled oxygen provides clear evidence that O(aq) originating from the gas phase enters the liquid and reacts directly with phenol, without any intermediate reactions. Additionally, the atmospheric-pressure plasma source demonstrates great potential to be an effective source of O(aq) atoms without the requirement for any precursors in the liquid phase.

Mohamed Mokhtar Saad Fahim Hefny

05/06/2017

https://www.nature.com/articles/s41598-017-03131-y.pdf

Mohamed Mokhtar Saad Fahim Hefny

01/01/2012

The One Atmosphere Uniform Glow Discharge Plasma Panel (OAUGDP) is a kind of panel that allows making some sharp and clear pictures of glow and cold discharge plasma. The panel is a sheet that made of polystyrene foam. The (OAUGDP) in our laboratory was created by two techniques; manual and electronic. The electric fields employed to create the OAUGDP are normally less than 10 kV/cm in air and 2–3 kV/cm in argon and helium. The aim of this work is to measure and calculate the electrical parameters of plasma using these two different circuits. A high voltage probe is used to measure the plasma voltage and current for both manual and electronic circuits.

Mohamed Mokhtar Saad Fahim Hefny

01/01/2012

The One Atmosphere Uniform Glow Discharge Plasma Panel (OAUGDP) is a kind of panel that allows making some sharp and clear pictures of glow and cold discharge plasma. The panel is a sheet that made of polystyrene foam. The (OAUGDP) in our laboratory was created by two techniques; manual and electronic. The electric fields employed to create the OAUGDP are normally less than 10 kV/cm in air and 2–3 kV/cm in argon and helium. The aim of this work is to measure and calculate the electrical parameters of plasma using these two different circuits. A high voltage probe is used to measure the plasma voltage and current for both manual and electronic circuits.