The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Taegyu Kim - One of the best experts on this subject based on the ideXlab platform.
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mems solid propellant thruster array with micro membrane Igniter
Sensors and Actuators A-physical, 2013Co-Authors: Jongkwang Lee, Taegyu KimAbstract:Abstract A microIgniter with improved membrane for MEMS solid propellant thruster array is proposed. Although existing Igniters using dielectric SiN x membranes consume low power, they cannot withstand shocks during the propellant charging process. A glass wafer is selected as the material for the Igniter. A glass membrane is fabricated by the anisotropic wet etching of photosensitive glass. Platinum is used for the ignition coil. A 30–40-μm thick glass membrane exhibited sufficient strength to withstand accidental impacts during the propellant charging process. Further, the microIgniter using the glass membrane had an appropriate power consumption to ignite the solid propellant. The thermal, electrical, and mechanical characteristics of the fabricated microIgniter were measured. The proposed microIgniter provided the sufficient heat for the propellant to be ignited with the given electric power. The fracture pressure of the glass membrane was thrice higher than the conventional microIgniter. A solid propellant lead styphnate was filled into the microIgniter without any additional processes. Ignition tests with fully assembly MEMS thrusters were performed successfully. Thus, it is demonstrated that a simpler, robust, and low-cost fabrication process of an Igniter that performs well when assembled into a micro solid propellant thruster (MSPT) array is possible.
Sejin Kwon - One of the best experts on this subject based on the ideXlab platform.
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design fabrication and testing of mems solid propellant thruster array chip on glass wafer
Sensors and Actuators A-physical, 2010Co-Authors: Sejin KwonAbstract:This paper presents the internal ballistic design, fabrication procedure, and performance evaluation of a micro-electro mechanical systems (MEMS) solid propellant thruster array chip. The internal ballistic design was carried out to predict the performance of the thruster. Two different ignition models were used. The numerical results gave a maximum thrust of 3840 mN, and a total impulse of 0.42 mNs at the local ignition model. A photosensitive glass wafer only was used as the bare material for the thruster. The stability of the micro-Igniter was improved by using a glass membrane with a thickness of tens of microns. The average thickness of the membrane was 35 μm. The proposed micro-Igniter had a level of power consumption appropriate to ignite the solid propellant. The thermal, electrical, and mechanical characteristics of the fabricated micro-Igniter were measured. The solid propellant was loaded into the propellant chamber without resort to a special technique due to the high structural stability of the glass membrane. An MEMS solid propellant thruster (MSPT) array was fabricated through anisotropic etching of photosensitive glass. An ignition control system was developed to control the ignition sequence. Ignition and combustion tests of the fully assembly MEMS thruster were performed successfully. The minimum ignition delay was 27.5 ms with an ignition energy of 19.3 mJ. The average of the measured maximum thrust and total impulse were 3619 mN and 0.381 mNs, respectively.
Jongkwang Lee - One of the best experts on this subject based on the ideXlab platform.
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mems solid propellant thruster array with micro membrane Igniter
Sensors and Actuators A-physical, 2013Co-Authors: Jongkwang Lee, Taegyu KimAbstract:Abstract A microIgniter with improved membrane for MEMS solid propellant thruster array is proposed. Although existing Igniters using dielectric SiN x membranes consume low power, they cannot withstand shocks during the propellant charging process. A glass wafer is selected as the material for the Igniter. A glass membrane is fabricated by the anisotropic wet etching of photosensitive glass. Platinum is used for the ignition coil. A 30–40-μm thick glass membrane exhibited sufficient strength to withstand accidental impacts during the propellant charging process. Further, the microIgniter using the glass membrane had an appropriate power consumption to ignite the solid propellant. The thermal, electrical, and mechanical characteristics of the fabricated microIgniter were measured. The proposed microIgniter provided the sufficient heat for the propellant to be ignited with the given electric power. The fracture pressure of the glass membrane was thrice higher than the conventional microIgniter. A solid propellant lead styphnate was filled into the microIgniter without any additional processes. Ignition tests with fully assembly MEMS thrusters were performed successfully. Thus, it is demonstrated that a simpler, robust, and low-cost fabrication process of an Igniter that performs well when assembled into a micro solid propellant thruster (MSPT) array is possible.
Cheng-che Hsu - One of the best experts on this subject based on the ideXlab platform.
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Plasmas in Saline Solution Sustained Using Bipolar Pulsed Power Source: Tailoring the Discharge Behavior Using the Negative Pulses
Plasma Chemistry and Plasma Processing, 2013Co-Authors: Hung-wen Chang, Cheng-che HsuAbstract:Plasmas in saline solution driven by a repetitive bipolar pulsed power source are studied. We use a negative pulse to generate electrolytic gas with a controllable amount, followed by a positive pulse to ignite the plasma. With an increase in the negative voltage pulse amplitude from 0 to −80 V, we observed an increase in the amount of electrolytic gas (hydrogen) formation, resulting in a reduced time delay, from 65 to 6 μs, required to ignite the plasma upon the onset of the positive pulse. A decrease, from 1.75 to 1.0 A, in the peak currents within the positive voltage pulse is also observed. Optical emission spectroscopy shows that the intensity ratio of the H_α (656 nm) to Na (588 nm) emission lines increases from zero to 0.0035. These observations can be well explained by the increase in the gas coverage on the electrode surface and the change in the gas composition within which the plasma is ignited with the application of the negative pulse.
Koshun Iha - One of the best experts on this subject based on the ideXlab platform.
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Qualification of Magnesium/Teflon/Viton Pyrotechnic Composition Used in Rocket Motors Ignition System
Journal of Aerospace Technology and Management, 2016Co-Authors: Luciana De Barros, Afonso Paulo Monteiro Pinheiro, Josemar Da Encarnação Câmara, Koshun IhaAbstract:The application of fluoropolymers in highenergy-release pyrotechnic compositions is common in the space and defense areas. Pyrotechnic compositions of magnesium/Teflon/Viton are widely used in military flares and pyrogen Igniters for igniting the solid propellant of a rocket motor. Pyrotechnic components are considered highrisk products as they may cause catastrophic accidents if initiated or ignited inadvertently. To reduce the hazards involved in the handling, storage and transportation of these devices, the magnesium/Teflon/Viton composition was subjected to various sensitivity tests, DSC and had its stability and compatibility tested with other materials. This composition obtained satisfactory results in all the tests, which qualifies it as safe for production, handling, use, storage and transportation.
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qualification of magnesium teflon viton pyrotechnic composition used in rocket motors ignition system
Journal of Aerospace Technology and Management, 2016Co-Authors: Luciana De Barros, Afonso Paulo Monteiro Pinheiro, Josemar Da Encarnação Câmara, Koshun IhaAbstract:The application of fluoropolymers in highenergy-release pyrotechnic compositions is common in the space and defense areas. Pyrotechnic compositions of magnesium/Teflon/Viton are widely used in military flares and pyrogen Igniters for igniting the solid propellant of a rocket motor. Pyrotechnic components are considered highrisk products as they may cause catastrophic accidents if initiated or ignited inadvertently. To reduce the hazards involved in the handling, storage and transportation of these devices, the magnesium/Teflon/Viton composition was subjected to various sensitivity tests, DSC and had its stability and compatibility tested with other materials. This composition obtained satisfactory results in all the tests, which qualifies it as safe for production, handling, use, storage and transportation.
