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	Author	Wang, W.-C.
	Title	Quantitative analysis of electron exit waves with single atom sensitivity			Type	Doctoral thesis
	Year	2011	Publication		Abbreviated Journal
	Volume		Issue		Pages
	Keywords	Doctoral thesis; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Antwerpen	Editor
	Language		Wos		Publication Date	0000-00-00
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ lucian @ c:irua:93201			Serial	2745
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	Author	Wang, W.; Patil, B.; Heijkers, S.; Hessel, V.; Bogaerts, A.
	Title	Nitrogen fixation by gliding arc plasma : better insight by chemical kinetics modelling			Type	A1 Journal article
	Year	2017	Publication	Chemsuschem	Abbreviated Journal	Chemsuschem
	Volume	10	Issue	10	Pages	2145-2157
	Keywords	A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	The conversion of atmospheric nitrogen into valuable compounds, that is, so-called nitrogen fixation, is gaining increased interest, owing to the essential role in the nitrogen cycle of the biosphere. Plasma technology, and more specifically gliding arc plasma, has great potential in this area, but little is known about the underlying mechanisms. Therefore, we developed a detailed chemical kinetics model for a pulsed-power gliding-arc reactor operating at atmospheric pressure for nitrogen oxide synthesis. Experiments are performed to validate the model and reasonable agreement is reached between the calculated and measured NO and NO2 yields and the corresponding energy efficiency for NOx formation for different N2/O2 ratios, indicating that the model can provide a realistic picture of the plasma chemistry. Therefore, we can use the model to investigate the reaction pathways for the formation and loss of NOx. The results indicate that vibrational excitation of N2 in the gliding arc contributes significantly to activating the N2 molecules, and leads to an energy efficient way of NOx production, compared to the thermal process. Based on the underlying chemistry, the model allows us to propose solutions on how to further improve the NOx formation by gliding arc technology. Although the energy efficiency of the gliding-arc-based nitrogen fixation process at the present stage is not comparable to the world-scale HaberBosch process, we believe our study helps us to come up with more realistic scenarios of entering a cutting-edge innovation in new business cases for the decentralised production of fertilisers for agriculture, in which low-temperature plasma technology might play an important role.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Weinheim	Editor
	Language		Wos	000402122100006	Publication Date	2017-03-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1864-5631	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	7.226	Times cited	42	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 7.226
	Call Number	UA @ lucian @ c:irua:143261			Serial	4672
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	Author	Kong, L.; Wang, W.; Murphy, A.B.; Xia, G.
	Title	Numerical analysis of direct-current microdischarge for space propulsion applications using the particle-in-cell/Monte Carlo collision (PIC/MCC) method			Type	A1 Journal article
	Year	2017	Publication	Journal of physics: D: applied physics	Abbreviated Journal	J Phys D Appl Phys
	Volume	50	Issue	16	Pages	165203
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Microdischarges are an important type of plasma discharge that possess several unique characteristics, such as the presence of a stable glow discharge, high plasma density and intense excimer radiation, leading to several potential applications. The intense and controllable gas heating within the extremely small dimensions of microdischarges has been exploited in microthruster technologies by incorporating a micro-nozzle to generate the thrust. This kind of microthruster has a significantly improved specific impulse performance compared to conventional cold gas thrusters, and can meet the requirements arising from the emerging development and application of micro-spacecraft. In this paper, we performed a self-consistent 2D particle-in-cell simulation, with a Monte Carlo collision model, of a microdischarge operating in a prototype micro-plasma thruster with a hollow cylinder geometry and a divergent micro-nozzle. The model takes into account the thermionic electron emission including the Schottky effect, the secondary electron emission due to cathode bombardment by the plasma ions, several different collision processes, and a non-uniform argon background gas density in the cathode-anode gap. Results in the high-pressure (several hundreds of Torr), high-current (mA) operating regime showing the behavior of the plasma density, potential distribution, and energy flux towards the hollow cathode and anode are presented and discussed. In addition, the results of simulations showing the effect of different argon gas pressures, cathode material work function and discharge voltage on the operation of the microdischarge thruster are presented. Our calculated properties are compared with experimental data under similar conditions and qualitative and quantitative agreements are reached.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	London	Editor
	Language		Wos	000398856300001	Publication Date	2017-02-22
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0022-3727	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.588	Times cited	8	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.588
	Call Number	UA @ lucian @ c:irua:143642			Serial	4674
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	Author	Wang, W.; Kong, L.; Geng, J.; Wei, F.; Xia, G.
	Title	Wall ablation of heated compound-materials into non-equilibrium discharge plasmas			Type	A1 Journal article
	Year	2017	Publication	Journal of physics: D: applied physics	Abbreviated Journal	J Phys D Appl Phys
	Volume	50	Issue	7	Pages	074005
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	The discharge properties of the plasma bulk flow near the surface of heated compound-materials strongly affects the kinetic layer parameters modeled and manifested in the Knudsen layer. This paper extends the widely used two-layer kinetic ablation model to the ablation controlled non-equilibrium discharge due to the fact that the local thermodynamic equilibrium (LTE) approximation is often violated as a result of the interaction between the plasma and solid walls. Modifications to the governing set of equations, to account for this effect, are derived and presented by assuming that the temperature of the electrons deviates from that of the heavy particles. The ablation characteristics of one typical material, polytetrafluoroethylene (PTFE) are calculated with this improved model. The internal degrees of freedom as well as the average particle mass and specific heat ratio of the polyatomic vapor, which strongly depends on the temperature, pressure and plasma non-equilibrium degree and plays a crucial role in the accurate determination of the ablation behavior by this model, are also taken into account. Our assessment showed the significance of including such modifications related to the non-equilibrium effect in the study of vaporization of heated compound materials in ablation controlled arcs. Additionally, a two-temperature magneto-hydrodynamic (MHD) model accounting for the thermal non-equilibrium occurring near the wall surface is developed and applied into an ablation-dominated discharge for an electro-thermal chemical launch device. Special attention is paid to the interaction between the non-equilibrium plasma and the solid propellant surface. Both the mass exchange process caused by the wall ablation and plasma species deposition as well as the associated momentum and energy exchange processes are taken into account. A detailed comparison of the results of the non-equilibrium model with those of an equilibrium model is presented. The non-equilibrium results show a non-equilibrium region near the plasma-wall interaction region and this indicates the need for the consideration of the influence of the possible departure from LTE in the plasma bulk on the determination of ablation rate.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	London	Editor
	Language		Wos	000394097200001	Publication Date	2017-01-24
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0022-3727	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.588	Times cited	19	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.588
	Call Number	UA @ lucian @ c:irua:141965			Serial	4702
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	Author	Wang, H.; Wang, W.; Yan, J.D.; Qi, H.; Geng, J.; Wu, Y.
	Title	Thermodynamic properties and transport coefficients of a two-temperature polytetrafluoroethylene vapor plasma for ablation-controlled discharge applications			Type	A1 Journal article
	Year	2017	Publication	Journal of physics: D: applied physics	Abbreviated Journal	J Phys D Appl Phys
	Volume	50	Issue	39	Pages	395204
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg-Waage equation according to van de Sanden et al's derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto's electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman-Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	London	Editor
	Language		Wos	000410390100001	Publication Date	2017-07-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0022-3727	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.588	Times cited	3	Open Access	Not_Open_Access
	Notes				Approved	Most recent IF: 2.588
	Call Number	UA @ lucian @ c:irua:145603			Serial	4754
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	Author	Zhang, H.; Wang, W.; Li, X.; Han, L.; Yan, M.; Zhong, Y.; Tu, X.
	Title	Plasma activation of methane for hydrogen production in a N₂ rotating gliding arc warm plasma : a chemical kinetics study			Type	A1 Journal article
	Year	2018	Publication	Chemical engineering journal	Abbreviated Journal	Chem Eng J
	Volume	345	Issue	345	Pages	67-78
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	In this work, a chemical kinetics study on methane activation for hydrogen production in a warm plasma, i.e., N-2 rotating gliding arc (RGA), was performed for the first time to get new insights into the underlying reaction mechanisms and pathways. A zero-dimensional chemical kinetics model was developed, which showed a good agreement with the experimental results in terms of the conversion of CH4 and product selectivities, allowing us to get a better understanding of the relative significance of various important species and their related reactions to the formation and loss of CH4, H-2, and C2H2 etc. An overall reaction scheme was obtained to provide a realistic picture of the plasma chemistry. The results reveal that the electrons and excited nitrogen species (mainly N-2(A)) play a dominant role in the initial dissociation of CH4. However, the H atom induced reaction CH4+ H -> CH3+ H-2, which has an enhanced reaction rate due to the high gas temperature (over 1200 K), is the major contributor to both the conversion of CH4 and H-2 production, with its relative contributions of > 90% and > 85%, respectively, when only considering the forward reactions. The coexistence and interaction of thermochemical and plasma chemical processes in the rotating gliding arc warm plasma significantly enhance the process performance. The formation of C-2 hydrocarbons follows a nearly one-way path of C2H6 -> C2H4 -> C2H2, explaining why the selectivities of C-2 products decreased in the order of C2H2 > C2H4 > C2H6.
	Address
	Corporate Author				Thesis
	Publisher	Elsevier Sequoia	Place of Publication	Lausanne	Editor
	Language		Wos	000430696500008	Publication Date	2018-03-24
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1385-8947; 1873-3212	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.216	Times cited	25	Open Access	OpenAccess
	Notes				Approved	Most recent IF: 6.216
	Call Number	UA @ lucian @ c:irua:151450			Serial	5036
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	Author	Trenchev, G.; Nikiforov, A.; Wang, W.; Kolev, S.; Bogaerts, A.
	Title	Atmospheric pressure glow discharge for CO₂ conversion : model-based exploration of the optimum reactor configuration			Type	A1 Journal article
	Year	2019	Publication	Chemical engineering journal	Abbreviated Journal	Chem Eng J
	Volume	362	Issue	362	Pages	830-841
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	We investigate the performance of an atmospheric pressure glow discharge (APGD) reactor for CO2 conversion in three different configurations, through experiments and simulations. The first (basic) configuration utilizes the well-known pin-to-plate design, which offers a limited conversion. The second configuration improves the reactor performance by employing a vortex-flow generator. The third, “confined” configuration is a complete redesign of the reactor, which encloses the discharge in a limited volume, significantly surpassing the conversion rate of the other two designs. The plasma properties are investigated using an advanced plasma model.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000457863500084	Publication Date	2019-01-18
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1385-8947; 1873-3212	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.216	Times cited	4	Open Access	Not_Open_Access: Available from 15.10.2019
	Notes				Approved	Most recent IF: 6.216
	Call Number	UA @ admin @ c:irua:157459			Serial	5269
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	Author	Wang, W.; Butterworth, T.; Bogaerts, A.
	Title	Plasma propagation in a single bead DBD reactor at different dielectric constants : insights from fluid modelling			Type	A1 Journal article
	Year	2021	Publication	Journal Of Physics D-Applied Physics	Abbreviated Journal	J Phys D Appl Phys
	Volume	54	Issue	21	Pages	214004
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Packed bed dielectric barrier discharge (PB-DBD) plasma reactors are very promising for various plasma catalysis applications, but the exact mechanisms of plasma-catalyst interaction are far from understood, because the plasma discharge and catalyst/packing properties are mutually dependent. To better understand the effect of packing dielectric material on the electrical plasma properties, we study here a single bead DBD plasma reactor operating in dry air, with beads of different dielectric constant and for different applied voltages, by means of fluid modelling validated by optical imaging experiments. Our study reveals that the plasma in the single bead DBD reactor can manifest itself in two different modalities, i.e. (a) polar discharges at the bead poles in contact with the electrodes, and (b) a streamer discharge caused by surface ionization waves, which bridges the gas gap. Beads with high dielectric constant result in localised electric field enhancement and hence yield a reduction of the applied voltage required for plasma production. At low applied voltage, the discharge appears as polar discharges between the bead and the electrodes, and upon higher voltage it undergoes a transition into a bridging streamer discharge. The transition voltage to the streamer mode rises for beads with higher dielectric constant. These observations are important for plasma catalysis applications. A higher dielectric constant yields a higher electric field and thus higher average electron energy and density, giving rise to more reactive species, but it also yields a confined discharge near the contact points of packing beads, limiting the interaction area between the catalyst and the active plasma species. In addition, our model reveals that the dielectric bead behaves as a capacitor and traps charges, which can explain the significant occurrence of partial discharging in PB-DBDs and non-parallelogram shaped Lissajous plots. Hence, equivalent circuit modelling of PB-DBDs should take into account the role of packing beads in charge trapping as a capacitor.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000626451000001	Publication Date	2021-02-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0022-3727	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.588	Times cited		Open Access	Not_Open_Access
	Notes				Approved	Most recent IF: 2.588
	Call Number	UA @ admin @ c:irua:177571			Serial	6772
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