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Alp Ozkan - One of the best experts on this subject based on the ideXlab platform.
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dbd in burst Mode Solution for more efficient co2 conversion
arXiv: Plasma Physics, 2016Co-Authors: Alp Ozkan, Thierry Dufour, Tiago Silva, Nikolay Britun, Rony Snyders, Francois Reniers, Annemie BogaertsAbstract:CO2 conversion into value-added products has gained significant interest over the few last years, as the greenhouse gas concentrations constantly increase due to anthropogenic activities. Here we report on experiments for CO2 conversion by means of a cold atmospheric plasma using a cylindrical flowing dielectric barrier discharge (DBD) reactor. A detailed comparison of this DBD ignited in a so-called burst Mode (i.e. where an AC voltage is applied during a limited amount of time) and pure AC Mode is carried out to evaluate their effect on the conversion of CO2 as well as on the energy efficiency. Decreasing the duty cycle in the burst Mode from 100% (i.e. corresponding to pure AC Mode) to 40% leads to a rise in the conversion from 16--26% and to a rise in the energy efficiency from 15 to 23%. Based on a detailed electrical analysis, we show that the conversion correlates with the features of the microfilaments. Moreover, the root-mean-square voltage in the burst Mode remains constant as a function of the process time for the duty cycles \textless{}70%, while a higher duty cycle or the usual pure AC Mode leads to a clear voltage decay by more than 500 V, over approximately 90 s, before reaching a steady state regime. The higher plasma voltage in the burst Mode yields a higher electric field. This causes the increasing the electron energy, and therefore their involvement in the CO2 dissociation process, which is an additional explanation for the higher CO2 conversion and energy efficiency in the burst Mode.
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dbd in burst Mode Solution for more efficient co2 conversion
Plasma Sources Science and Technology, 2016Co-Authors: Alp Ozkan, Thierry Dufour, Tiago Silva, Nikolay Britun, Rony Snyders, Francois Reniers, Annemie BogaertsAbstract:CO2 conversion into value-added products has gained significant interest over the few last years, as the greenhouse gas concentrations constantly increase due to anthropogenic activities. Here we report on experiments for CO2 conversion by means of a cold atmospheric plasma using a cylindrical flowing dielectric barrier discharge (DBD) reactor. A detailed comparison of this DBD ignited in a so-called burst Mode (i.e. where an AC voltage is applied during a limited amount of time) and pure AC Mode is carried out to evaluate their effect on the conversion of CO2 as well as on the energy efficiency. Decreasing the duty cycle in the burst Mode from 100% (i.e. corresponding to pure AC Mode) to 40% leads to a rise in the conversion from 16–26% and to a rise in the energy efficiency from 15 to 23%. Based on a detailed electrical analysis, we show that the conversion correlates with the features of the microfilaments. Moreover, the root-mean-square voltage in the burst Mode remains constant as a function of the process time for the duty cycles <70%, while a higher duty cycle or the usual pure AC Mode leads to a clear voltage decay by more than 500 V, over approximately 90 s, before reaching a steady state regime. The higher plasma voltage in the burst Mode yields a higher electric field. This causes the increasing the electron energy, and therefore their involvement in the CO2 dissociation process, which is an additional explanation for the higher CO2 conversion and energy efficiency in the burst Mode.
Annemie Bogaerts - One of the best experts on this subject based on the ideXlab platform.
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dbd in burst Mode Solution for more efficient co2 conversion
arXiv: Plasma Physics, 2016Co-Authors: Alp Ozkan, Thierry Dufour, Tiago Silva, Nikolay Britun, Rony Snyders, Francois Reniers, Annemie BogaertsAbstract:CO2 conversion into value-added products has gained significant interest over the few last years, as the greenhouse gas concentrations constantly increase due to anthropogenic activities. Here we report on experiments for CO2 conversion by means of a cold atmospheric plasma using a cylindrical flowing dielectric barrier discharge (DBD) reactor. A detailed comparison of this DBD ignited in a so-called burst Mode (i.e. where an AC voltage is applied during a limited amount of time) and pure AC Mode is carried out to evaluate their effect on the conversion of CO2 as well as on the energy efficiency. Decreasing the duty cycle in the burst Mode from 100% (i.e. corresponding to pure AC Mode) to 40% leads to a rise in the conversion from 16--26% and to a rise in the energy efficiency from 15 to 23%. Based on a detailed electrical analysis, we show that the conversion correlates with the features of the microfilaments. Moreover, the root-mean-square voltage in the burst Mode remains constant as a function of the process time for the duty cycles \textless{}70%, while a higher duty cycle or the usual pure AC Mode leads to a clear voltage decay by more than 500 V, over approximately 90 s, before reaching a steady state regime. The higher plasma voltage in the burst Mode yields a higher electric field. This causes the increasing the electron energy, and therefore their involvement in the CO2 dissociation process, which is an additional explanation for the higher CO2 conversion and energy efficiency in the burst Mode.
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dbd in burst Mode Solution for more efficient co2 conversion
Plasma Sources Science and Technology, 2016Co-Authors: Alp Ozkan, Thierry Dufour, Tiago Silva, Nikolay Britun, Rony Snyders, Francois Reniers, Annemie BogaertsAbstract:CO2 conversion into value-added products has gained significant interest over the few last years, as the greenhouse gas concentrations constantly increase due to anthropogenic activities. Here we report on experiments for CO2 conversion by means of a cold atmospheric plasma using a cylindrical flowing dielectric barrier discharge (DBD) reactor. A detailed comparison of this DBD ignited in a so-called burst Mode (i.e. where an AC voltage is applied during a limited amount of time) and pure AC Mode is carried out to evaluate their effect on the conversion of CO2 as well as on the energy efficiency. Decreasing the duty cycle in the burst Mode from 100% (i.e. corresponding to pure AC Mode) to 40% leads to a rise in the conversion from 16–26% and to a rise in the energy efficiency from 15 to 23%. Based on a detailed electrical analysis, we show that the conversion correlates with the features of the microfilaments. Moreover, the root-mean-square voltage in the burst Mode remains constant as a function of the process time for the duty cycles <70%, while a higher duty cycle or the usual pure AC Mode leads to a clear voltage decay by more than 500 V, over approximately 90 s, before reaching a steady state regime. The higher plasma voltage in the burst Mode yields a higher electric field. This causes the increasing the electron energy, and therefore their involvement in the CO2 dissociation process, which is an additional explanation for the higher CO2 conversion and energy efficiency in the burst Mode.
Yizen Chu - One of the best experts on this subject based on the ideXlab platform.
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a line source in minkowski for the de sitter spacetime scalar green s function massless minimally coupled case
Journal of Mathematical Physics, 2014Co-Authors: Yizen ChuAbstract:Motivated by the desire to understand the causal structure of physical signals produced in curved spacetimes – particularly around black holes – we show how, for certain classes of geometries, one might obtain its retarded or advanced minimally coupled massless scalar Green's function by using the corresponding Green's functions in the higher dimensional Minkowski spacetime where it is embedded. Analogous statements hold for certain classes of curved Riemannian spaces, with positive definite metrics, which may be embedded in higher dimensional Euclidean spaces. The general formula is applied to (d ≥ 2)-dimensional de Sitter spacetime, and the scalar Green's function is demonstrated to be sourced by a line emanating infinitesimally close to the origin of the ambient (d + 1)-dimensional Minkowski spacetime and piercing orthogonally through the de Sitter hyperboloids of all finite sizes. This method does not require solving the de Sitter wave equation directly. Only the zero Mode Solution to an ordinary differential equation, the “wave equation” perpendicular to the hyperboloid – followed by a one-dimensional integral – needs to be evaluated. A topological obstruction to the general construction is also discussed by utilizing it to derive a generalized Green's function of the Laplacian on the (d ≥ 2)-dimensional sphere.
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a line source in minkowski for the de sitter spacetime scalar green s function massless minimally coupled case
Journal of Mathematical Physics, 2014Co-Authors: Yizen ChuAbstract:Motivated by the desire to understand the causal structure of physical signals produced in curved spacetimes – particularly around black holes – we show how, for certain classes of geometries, one might obtain its retarded or advanced minimally coupled massless scalar Green's function by using the corresponding Green's functions in the higher dimensional Minkowski spacetime where it is embedded. Analogous statements hold for certain classes of curved Riemannian spaces, with positive definite metrics, which may be embedded in higher dimensional Euclidean spaces. The general formula is applied to (d ≥ 2)-dimensional de Sitter spacetime, and the scalar Green's function is demonstrated to be sourced by a line emanating infinitesimally close to the origin of the ambient (d + 1)-dimensional Minkowski spacetime and piercing orthogonally through the de Sitter hyperboloids of all finite sizes. This method does not require solving the de Sitter wave equation directly. Only the zero Mode Solution to an ordinary diff...
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a line source in minkowski for the de sitter spacetime scalar green s function massless minimally coupled case
arXiv: General Relativity and Quantum Cosmology, 2013Co-Authors: Yizen ChuAbstract:Motivated by the desire to understand the causal structure of physical signals produced in curved spacetimes -- particularly around black holes -- we show how, for certain classes of geometries, one might obtain its retarded or advanced minimally coupled massless scalar Green's function by using the corresponding Green's functions in the higher dimensional Minkowski spacetime where it is embedded. Analogous statements hold for certain classes of curved Riemannian spaces, with positive definite metrics, which may be embedded in higher dimensional Euclidean spaces. The general formula is applied to $(d \geq 2)$-dimensional de Sitter spacetime, and the scalar Green's function is demonstrated to be sourced by a line emanating infinitesimally close to the origin of the ambient $(d+1)$-dimensional Minkowski spacetime and piercing orthogonally through the de Sitter hyperboloids of all finite sizes. This method does not require solving the de Sitter wave equation directly. Only the zero Mode Solution to an ordinary differential equation, the "wave equation" perpendicular to the hyperboloid -- followed by a one dimensional integral -- needs to be evaluated. A topological obstruction to the general construction is also discussed by utilizing it to derive a generalized Green's function of the Laplacian on the $(d \geq 2)$-dimensional sphere.
L G Kazovsky - One of the best experts on this subject based on the ideXlab platform.
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ultraflow access testbed experimental exploration of dual Mode access networks
IEEE\ OSA Journal of Optical Communications and Networking, 2013Co-Authors: Shuang Yin, Ahmad R Dhaini, Thomas Shun Rong Shen, Benjamin A Detwiler, Marc De Leenheer, Talip Ucar, L G KazovskyAbstract:Electrical packet switching is well known as a flexible Solution for small data transfers, whereas optical flow switching (OFS) might be an effective Solution for large Internet file transfers. The UltraFlow project, a joint effort of three universities, Stanford, Massachusetts Institute of Technology, and University of Texas-Dallas, aims at providing an efficient dual-Mode Solution (i.e., IP and OFS) to the current network. In this paper, we propose and experimentally demonstrate UltraFlow Access, a novel optical access network that enables dual-Mode service to the end users: IP and OFS. The new architecture cooperates with legacy passive optical networks (PONs) to provide both IP and novel OFS services. The latter is facilitated by a novel optical flow network unit (OFNU) that we have proposed, designed, and experimentally demonstrated. Different colored and colorless OFNU designs are presented, and their impact on the network performance is explored. Our testbed experiments demonstrate concurrent bidirectional 1.25 Gbps IP and 10 Gbps per-wavelength Flow error-free communication delivered over the same infrastructure. The support of intra-PON OFS communication, that is, between two OFNUs in the same PON, is also explored and experimentally demonstrated.
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ultraflow access networks a dual Mode Solution for the access bottleneck
International Conference on Transparent Optical Networks, 2013Co-Authors: L G Kazovsky, Shuang Yin, Ahmad R Dhaini, Thomas Shun Rong Shen, Marc De Leenheer, Benjamin A DetwilerAbstract:Optical Flow Switching (OFS) is promised to be an efficient Solution for large Internet data transfers. In this paper, we introduce UltraFlow Access, a novel optical access network architecture that offers dual-Mode service to its end-users: IP and OFS. With UltraFlow Access, we design and implement a new control plane and a novel dual-Mode network stack to ensure efficient connection setup, and reliable and optimal data transmission. Experimental testbed results demonstrate concurrent error-free transmission of 10 Gbps per-wavelength OFS and 1.25 Gbps conventional IP, delivered over the same infrastructure.
Takahito Arai - One of the best experts on this subject based on the ideXlab platform.
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asynchronous development of the benjamin feir unstable Mode Solution of the davey stewartson equation
Physical Review E, 2001Co-Authors: Masayoshi Tajiri, Kiyohiro Takeuchi, Takahito AraiAbstract:The long time evolution of the Benjamin-Feir unstable Mode in two dimension is described by the growing-and-decaying Mode Solution to the Davey-Stewartson equation. The Solution of the hyperbolic Davey-Stewartson (the so-called Davey-Stewartson I) equation is analyzed to show that the resonance between line soliton and growing-and-decaying Mode exists. If the resonant condition is exactly satisfied, the growing-and-decaying Mode exists only in the forward region of propagation of soliton and the soliton is accelerated (or decelerated). Under the quasiresonant condition, the growing-and-decaying Mode grows at first in the forward region, and after the sequence of the evolution has done in the forward region the Mode starts to grow in the backward region of the soliton.
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growing and decaying Mode Solution to the davey stewartson equation
Physical Review E, 1999Co-Authors: Masayoshi Tajiri, Takahito AraiAbstract:The growing-and-decaying Mode Solution to the Davey-Stewartson equation are presented, which describe the long time evolution of the Benjamin-Feir unstable Mode in two dimensions. A Solution consisting of a line soliton and a growing-and-decaying Mode shows that the Benjamin-Feir unstable Mode does not destroy the structure of the line soliton. The breather Solution and rational growing-and-decaying Mode Solution are also presented.