The Experts below are selected from a list of 26199 Experts worldwide ranked by ideXlab platform
Fuzhu Han - One of the best experts on this subject based on the ideXlab platform.
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on sustainable manufacturing titanium alloy by high speed edm milling with moving Electric Arcs while using water based diElectric
Journal of Cleaner Production, 2018Co-Authors: Zhaojun Kou, Fuzhu HanAbstract:Abstract In order to solve the environmental pollution and low machining efficiency of conventional EDM process, a sustainable manufacturing method of high-speed EDM milling while using water-based diElectric is proposed. Firstly, the machining principle of moving Electric Arcs was investigated. Then, models were established and utilized to explain the characteristics of high-speed EDM milling with moving Electric Arcs. Experiments on machining titanium alloy with this method were carried out to analyze the machining characteristics. The experimental results showed that the material removal rate (MRR) was significantly improved. The maximum MRR was almost five times greater than that of conventional EDM. Moreover, the lower tool-electrode wear in high-speed EDM milling was obtained, which can be attributed to the high-speed rotation of tool-electrode and protective layer formation on the tool-electrode surface caused by sputtering and deposition of Ti-6Al-4V.
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machining characteristics and removal mechanisms of moving Electric Arcs in high speed edm milling
Journal of Manufacturing Processes, 2018Co-Authors: Zhaojun Kou, Fuzhu HanAbstract:Abstract Low machining efficiency is the major challenges of conventional Electrical discharge machining (EDM). To resolve this problem, a novel machining method of high-speed EDM milling with moving Electric Arcs was developed, which can remove material continuously without discharge intervals of pulse power supply and achieve extremely low tool-electrode wear for the direct-current power supply employed. An EDM milling equipment was devised to explore machining characteristics and removal mechanisms of moving Electric Arcs in high-speed EDM milling process. Firstly of all, the motion characteristics of moving Electric Arcs were investigated. The theoretical analysis shows that the Arcs maintain an independent movement relative to the tool-electrode and workpiece. Then, the plasma channels were captured by high-speed video camera, which contributed to develop the model of removal mechanisms of moving Electric Arcs. Finally, the machining experiments were carried out based on titanium alloy, which verified that a much higher material removal rate could be easily achieved by moving Electric arc. Moreover, the tool-electrode wear in high-speed EDM milling is much lower than conventional EDM due to the protective layer formation.
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machining mechanisms and characteristics of moving Electric Arcs in high speed edm milling
Procedia CIRP, 2018Co-Authors: Zhaojun Kou, Fuzhu HanAbstract:Abstract A novel machining process of high-speed EDM milling with moving Electric Arcs was developed, which can remove material continuously without discharge intervals of pulse power supply and achieve extremely low electrode tool wear for the direct-current power supply employed. An EDM equipment was devised to explore machining characteristics and removal mechanisms of moving Electric arc in high-speed EDM milling process. Firstly, the motion characteristics and resistance properties of moving Electric arc were investigated. The theoretical analysis shows that the Arcs maintain a relatively independent movement between the electrode and workpiece. Then, the plasma channel of Electric arc was captured by high-speed video camera to explore the machining mechanisms of the moving Electrical arc. Finally, the machining experiments were carried out based on titanium alloy, which verified the above mechanisms and a much higher material removal rate could be easily achieved by moving Electric arc. Moreover, the tool electrode wear in high-speed EDM milling is much lower than conventional EDM due to the protective layer formation.
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High-speed EDM milling with moving Electric Arcs
International Journal of Machine Tools and Manufacture, 2009Co-Authors: Fuzhu Han, Yongxain Wang, Ming ZhouAbstract:A novel high-speed Electrical discharge machining (EDM) milling method using moving Electric Arcs has been proposed in this study. We connected a copper electrode rotating rapidly around its axis and a work piece to a DC power supply to generate a moving Electric arc. To ensure high relative speed of any point on the electrode with respect to the work piece, the electrode was shaped like a pipe. It was observed that the Electric Arcs move rapidly within the discharge gap due to the revolution of the tool electrode, removing the materials on the electrode along the track of the arc roots. To explore the characteristics of machining with moving Electric Arcs, an EDM milling apparatus was devised. Two planes with approximately the same roughness were machined separately by this equipment and a traditional EDM machine for comparison. It was found that a much higher material removal rate can be easily achieved by EDM milling with moving Electric Arcs. In the meanwhile, wear of the tool electrode in this new method is negligible, which is greatly favorable for machining accuracy. The microstructures of these surfaces were also investigated for further information.
Jeanphilippe Monchoux - One of the best experts on this subject based on the ideXlab platform.
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spark plasma sintering mechanisms at the necks between tial powder particles
Acta Materialia, 2016Co-Authors: Zofia Trzaska, Alain Couret, Jeanphilippe MonchouxAbstract:Abstract In order to precise the role of the Electric current involved in the spark plasma sintering (SPS) technique on the microscopic mechanisms occurring at the necks between TiAl powder particles during densification, transmission electron microscopy thin foils have been extracted at the necks on interrupted states, for the first time, by focused ion beam. Microscopic plasticity mechanisms and recovery-recrystallization phenomena have been identified. The densification rate, which has been shown in this study to occur by deformation of the powder particles at a deformation rate of 10 −3 s −1 , can be accounted for by these phenomena. In particular, no specific effect, as signs of Electric Arcs, plasma or local overheating for example, induced by the SPS current, have been detected.
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Spark plasma sintering mechanisms at the necks between TiAl powder particles
Acta Materialia, 2016Co-Authors: Zofia Trzaska, Alain Couret, Jeanphilippe MonchouxAbstract:In order to precise the role of the Electric current involved in the spark plasma sintering (SPS) technique on the microscopic mechanisms occurring at the necks between TiAl powder particles during densification, transmission electron microscopy thin foils have been extracted at the necks on interrupted states, for the first time, by focused ion beam. Microscopic plasticity mechanisms and recovery-recrystallization phenomena have been identified. The densification rate, which has been shown in this study to occur by deformation of the powder particles at a deformation rate of 10−3 s−1, can be accounted for by these phenomena. In particular, no specific effect, as signs of Electric Arcs, plasma or local overheating for example, induced by the SPS current, have been detected. © 2016 Acta Materialia Inc.
Flavien Pillet - One of the best experts on this subject based on the ideXlab platform.
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Electrical discharges in water induce spores' DNA damage
PLoS ONE, 2018Co-Authors: Camille Lamarche, Marie-pierre Rols, Charlotte Da Silva, Gauthier Demol, Etienne Dague, Flavien PilletAbstract:Bacterial spores are one of the most resilient life forms on earth and are involved in many human diseases, such as infectious diarrhea, fatal paralytic illnesses and respiratory infections. Here, we investigated the mechanisms involved in the death of Bacillus pumilus spores after exposure to Electric Arcs in water. Cutting-edge microscopies at the nanoscale did not reveal any structural disorganization of spores exposed to Electric Arcs. This result suggested the absence of physical destruction by a propagating shock wave or an exposure to an Electric field. However, Pulsed-Field Gel Electrophoresis (PFGE) revealed genomic DNA damage induced by UV radiation and Reactive Oxygen Species (ROS). UV induced single-strand DNA breaks and thymine dimers while ROS were mainly involved in base exci-sion. Our findings revealed a correlation between DNA damage and the treatment of spores with Electrical discharges.
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Electric Arcs do not induce morphological damage on spores.
2018Co-Authors: Camille Lamarche, Marie-pierre Rols, Charlotte Da Silva, Gauthier Demol, Etienne Dague, Flavien PilletAbstract:(a) SEM image showing a population of untreated spores. Inset shows the location of a zoomed individual spore. (b) High resolution image of a control spore. The white arrow exhibited the protein ridges on spore coat surface. (c) Exposed spores visualized by SEM image after 500 Electric Arcs exposure. (d) High resolution image of an exposed spore. The Electric Arcs did not induce disruption of protein ridges (white arrow). Scale bars: 500 nm. (e) Statistical analysis of the spore volume. No variation was observed between untreated and exposed spores. (f) Frequency distribution of the volume of spores in control condition (black bars) and spores exposed (grey bars). Lines indicated the fitted gauss curves. The volumes were calculated from 100 spores in both conditions.
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Electric Arcs do not lead to the destruction of the spore structure.
2018Co-Authors: Camille Lamarche, Marie-pierre Rols, Charlotte Da Silva, Gauthier Demol, Etienne Dague, Flavien PilletAbstract:(a) Example of TEM image of an untreated spore. Inset revealed the structure of the spores at the nanoscale. The core (Co), the cortex (Cx) and the coat (Ct) are visualized. (b) TEM image of a typical spore exposed to Electric Arcs. The spore structure is similar to that of untreated spore. Scale bars: 50 nm. At least, 10 spores were imaged for each condition and one representative image was shown.
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Schematic illustration of the phenomenon involved in spore inactivation during Electric Arcs exposure.
2018Co-Authors: Camille Lamarche, Marie-pierre Rols, Charlotte Da Silva, Gauthier Demol, Etienne Dague, Flavien PilletAbstract:The core contained DNA supercoiled, SASPs, water, dipicolinic acids and Ca2+. The morphology and the spore structure were not affected during Electric Arcs exposure. Many DNA damage were observed after spore inactivation. UV radiation induced single-strand DNA breaks and pyrimidine dimers formation (thymine or cytosine dimers). Reactive Oxygen Species (ROS) were mainly implicated in base excision and moderately involved in single-strand DNA breaks and thymine dimer. Red dots represent ROS.
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Inactivation of spores by Electric Arcs
BMC Microbiology, 2016Co-Authors: Flavien Pillet, Igor Marjanovič, Matej Reberšek, Marie-pierre Rols, Damijan Miklavčič, Tadej KotnikAbstract:BackgroundIn the context of spore contamination involved in bio-terrorism and food preservation, the development of new techniques for spore inactivation is an important challenge.ResultsHere, a successful application of Electric arc discharges resulting in spore death was reported. Two types of Electric Arcs were compared, different with respect to their durations. The discharges with 0.5 μs duration induced a small inactivation area of 0.6 % of surface treated around their point of entry into the sample, while those with 20 μs duration induced a much larger inactivation area from 7 to 55 % of surface treated roughly proportional to the number of discharges delivered. In particular, 50 discharges of 20 μs duration induced inactivation in more than 55% of surface treated at an inactivation rate above 3.6 log10.ConclusionsThese results are promising and warrant developing Electric arcing as a novel method for spore inactivation.
Zofia Trzaska - One of the best experts on this subject based on the ideXlab platform.
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spark plasma sintering mechanisms at the necks between tial powder particles
Acta Materialia, 2016Co-Authors: Zofia Trzaska, Alain Couret, Jeanphilippe MonchouxAbstract:Abstract In order to precise the role of the Electric current involved in the spark plasma sintering (SPS) technique on the microscopic mechanisms occurring at the necks between TiAl powder particles during densification, transmission electron microscopy thin foils have been extracted at the necks on interrupted states, for the first time, by focused ion beam. Microscopic plasticity mechanisms and recovery-recrystallization phenomena have been identified. The densification rate, which has been shown in this study to occur by deformation of the powder particles at a deformation rate of 10 −3 s −1 , can be accounted for by these phenomena. In particular, no specific effect, as signs of Electric Arcs, plasma or local overheating for example, induced by the SPS current, have been detected.
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Spark plasma sintering mechanisms at the necks between TiAl powder particles
Acta Materialia, 2016Co-Authors: Zofia Trzaska, Alain Couret, Jeanphilippe MonchouxAbstract:In order to precise the role of the Electric current involved in the spark plasma sintering (SPS) technique on the microscopic mechanisms occurring at the necks between TiAl powder particles during densification, transmission electron microscopy thin foils have been extracted at the necks on interrupted states, for the first time, by focused ion beam. Microscopic plasticity mechanisms and recovery-recrystallization phenomena have been identified. The densification rate, which has been shown in this study to occur by deformation of the powder particles at a deformation rate of 10−3 s−1, can be accounted for by these phenomena. In particular, no specific effect, as signs of Electric Arcs, plasma or local overheating for example, induced by the SPS current, have been detected. © 2016 Acta Materialia Inc.
Marie-pierre Rols - One of the best experts on this subject based on the ideXlab platform.
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Electrical discharges in water induce spores' DNA damage
PLoS ONE, 2018Co-Authors: Camille Lamarche, Marie-pierre Rols, Charlotte Da Silva, Gauthier Demol, Etienne Dague, Flavien PilletAbstract:Bacterial spores are one of the most resilient life forms on earth and are involved in many human diseases, such as infectious diarrhea, fatal paralytic illnesses and respiratory infections. Here, we investigated the mechanisms involved in the death of Bacillus pumilus spores after exposure to Electric Arcs in water. Cutting-edge microscopies at the nanoscale did not reveal any structural disorganization of spores exposed to Electric Arcs. This result suggested the absence of physical destruction by a propagating shock wave or an exposure to an Electric field. However, Pulsed-Field Gel Electrophoresis (PFGE) revealed genomic DNA damage induced by UV radiation and Reactive Oxygen Species (ROS). UV induced single-strand DNA breaks and thymine dimers while ROS were mainly involved in base exci-sion. Our findings revealed a correlation between DNA damage and the treatment of spores with Electrical discharges.
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Electric Arcs do not induce morphological damage on spores.
2018Co-Authors: Camille Lamarche, Marie-pierre Rols, Charlotte Da Silva, Gauthier Demol, Etienne Dague, Flavien PilletAbstract:(a) SEM image showing a population of untreated spores. Inset shows the location of a zoomed individual spore. (b) High resolution image of a control spore. The white arrow exhibited the protein ridges on spore coat surface. (c) Exposed spores visualized by SEM image after 500 Electric Arcs exposure. (d) High resolution image of an exposed spore. The Electric Arcs did not induce disruption of protein ridges (white arrow). Scale bars: 500 nm. (e) Statistical analysis of the spore volume. No variation was observed between untreated and exposed spores. (f) Frequency distribution of the volume of spores in control condition (black bars) and spores exposed (grey bars). Lines indicated the fitted gauss curves. The volumes were calculated from 100 spores in both conditions.
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Electric Arcs do not lead to the destruction of the spore structure.
2018Co-Authors: Camille Lamarche, Marie-pierre Rols, Charlotte Da Silva, Gauthier Demol, Etienne Dague, Flavien PilletAbstract:(a) Example of TEM image of an untreated spore. Inset revealed the structure of the spores at the nanoscale. The core (Co), the cortex (Cx) and the coat (Ct) are visualized. (b) TEM image of a typical spore exposed to Electric Arcs. The spore structure is similar to that of untreated spore. Scale bars: 50 nm. At least, 10 spores were imaged for each condition and one representative image was shown.
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Schematic illustration of the phenomenon involved in spore inactivation during Electric Arcs exposure.
2018Co-Authors: Camille Lamarche, Marie-pierre Rols, Charlotte Da Silva, Gauthier Demol, Etienne Dague, Flavien PilletAbstract:The core contained DNA supercoiled, SASPs, water, dipicolinic acids and Ca2+. The morphology and the spore structure were not affected during Electric Arcs exposure. Many DNA damage were observed after spore inactivation. UV radiation induced single-strand DNA breaks and pyrimidine dimers formation (thymine or cytosine dimers). Reactive Oxygen Species (ROS) were mainly implicated in base excision and moderately involved in single-strand DNA breaks and thymine dimer. Red dots represent ROS.
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Inactivation of spores by Electric Arcs
BMC Microbiology, 2016Co-Authors: Flavien Pillet, Igor Marjanovič, Matej Reberšek, Marie-pierre Rols, Damijan Miklavčič, Tadej KotnikAbstract:BackgroundIn the context of spore contamination involved in bio-terrorism and food preservation, the development of new techniques for spore inactivation is an important challenge.ResultsHere, a successful application of Electric arc discharges resulting in spore death was reported. Two types of Electric Arcs were compared, different with respect to their durations. The discharges with 0.5 μs duration induced a small inactivation area of 0.6 % of surface treated around their point of entry into the sample, while those with 20 μs duration induced a much larger inactivation area from 7 to 55 % of surface treated roughly proportional to the number of discharges delivered. In particular, 50 discharges of 20 μs duration induced inactivation in more than 55% of surface treated at an inactivation rate above 3.6 log10.ConclusionsThese results are promising and warrant developing Electric arcing as a novel method for spore inactivation.