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The concept and design of a novel drag enhancement system called the Ultra-thin Wires Drag Enhancement System (UWDES), is presented. The UWDES uses numerous ultra-thin wires to form a three dimensional (3D) web through electrostat...
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The concept and design of a novel drag enhancement system called the Ultra-thin Wires Drag Enhancement System (UWDES), is presented. The UWDES uses numerous ultra-thin wires to form a three dimensional (3D) web through electrostatic charging. UWDES is designed with the objective of mitigating space debris, particularly in low altitude Earth orbits (LEOs) for pico/nano/micro-satellites by causing their rapid orbital decay. The ultra-thin drag-wires are stowed inside the container module of UWDES and at the end of spacecraft's mission life, deployed by releasing the container lid, followed by electrostatic charging. In comparison to drag sails, the UWDES drag-wires provide more effective area experiencing drag (EAED) for a given mass and size of the material used to fabricate the drag enhancing structure. For a unit cube of side 1 cm, (i) beaten into a square sheet of 1 micron thickness and (ii) drawn into a round wire of same thickness, the EAED for (i) is 1 m~2 and (ii) is 1.2732 m~2. The ultra-thin drag-wires of the UWDES are held straight in a tuft with all strands fused together at both ends. When they are electrostatically charged, due to mutual repulsion on acquiring like charges, they unwind from spool and deploy out of container module to gradually arrange into a 3D web structure. With this, all the individual ultra-thin drag-wire strands are exposed to incoming atoms and ions of space atmosphere and thus augment the effective area experiencing drag (EAED) of the host spacecraft and the resultant aero drag. As the drag wires are electrostatically charged, they mutually repel with like-charged particles of space atmosphere that collide with them resulting in Coulomb drag. Hybrid-drag effect of both Aero drag and Coulomb drag are responsible for stretching the ceiling altitude for UWDES application up to 6000 km. Based on the amount of charges supplied to the wires, the UWDES is designed to arrange itself into various 3D configurations (boat-shape, spindle/pear
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An interdisciplinary Research-based Education Program for Engaging Plant/Agriculture sciences,Chemical sciences and Engineering students(iREP-4-PACE)is envisioned with the underlying intent to improve Tuskegee University's(TU's)ST...
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An interdisciplinary Research-based Education Program for Engaging Plant/Agriculture sciences,Chemical sciences and Engineering students(iREP-4-PACE)is envisioned with the underlying intent to improve Tuskegee University's(TU's)STEM retention through the introduction of interdisciplinary,guided,inquiry experiments focused on the production of high-value chemicals from plants.At large,chemicals are synthesized from petroleum resources and it is well established that the continued extraction of these resources is detrimental to the environment.On the contrary,synthesizing chemicals from"plant factories"may be a boon to the environment and have a negative carbon footprint.The program uses three initiatives:a)expanded professional development activities for developing,teaching inquiry-based lectures and experiments,b)inclusion of sustainable high-value chemical production from plants across the laboratory curriculum,and c)increase of student hands-on access,competency with instrumentation and cutting-edge techniques.The overarching goal of the iREP-4-PACE program is to engage a cohort of undergraduates from plant/agriculture sciences,chemical sciences,and engineering disciplines in the research,education of engineering chemicals from plants of high commercial and medicinal value.The program will educate the undergraduates in engineering environment friendly chemicals.The year-long program will train students in seeking/learning the interdisciplinary knowledge,techniques of molecular synthesis of plant-based chemicals and in doing so,it will train the students in broadly applicable research methods such as literature review,instrument training,basic statistical analysis,and proposal writing.The article describes the design of the iREP-4-PACE program and activities conducted to gauge the interest of potential participants.
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This research was undertaken at the author's previous institution, which has a special status in Aerospace Engineering and shoulders the responsibility of graduating the most African Americans in Aerospace Engineering at an instit...
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This research was undertaken at the author's previous institution, which has a special status in Aerospace Engineering and shoulders the responsibility of graduating the most African Americans in Aerospace Engineering at an institution. Due to its established credibility, the university recruit aspirants from across the nation but particularly so from in and around its state. Quite often, the aspirants seeking a career in Aerospace Engineering are under prepared as freshman and it carries over even when they transition to becoming juniors and seniors. To maximize the chances of graduation for these underprepared students, several courses are repeated in the same year. To facilitate revision of the material presented in class, the author recorded his lectures as videos and archived them on YouTube - a popular online repository for multimedia content. Based on this archive, created over several years, the author implemented a flipped classroom model for an experimental offering of a course in Aerospace Engineering. The article discusses the need for a flipped classroom, the approach, and its impact on the students.
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摘要 :
This research was undertaken at the author's previous institution, which has a special status in Aerospace Engineering and shoulders the responsibility of graduating the most African Americans in Aerospace Engineering at an instit...
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This research was undertaken at the author's previous institution, which has a special status in Aerospace Engineering and shoulders the responsibility of graduating the most African Americans in Aerospace Engineering at an institution. Due to its established credibility, the university recruit aspirants from across the nation but particularly so from in and around its state. Quite often, the aspirants seeking a career in Aerospace Engineering are under prepared as freshman and it carries over even when they transition to becoming juniors and seniors. To maximize the chances of graduation for these underprepared students, several courses are repeated in the same year. To facilitate revision of the material presented in class, the author recorded his lectures as videos and archived them on YouTube - a popular online repository for multimedia content. Based on this archive, created over several years, the author implemented a flipped classroom model for an experimental offering of a course in Aerospace Engineering. The article discusses the need for a flipped classroom, the approach, and its impact on the students.
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In a compactly designed satellite, particularly those hosting magnetic or electric motor based actuators, the magnetic field distribution is continuously changing and can adversely affect the sensor/instrument measurements capture...
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In a compactly designed satellite, particularly those hosting magnetic or electric motor based actuators, the magnetic field distribution is continuously changing and can adversely affect the sensor/instrument measurements captured for attitude/orbit computations or science data collection. The purpose of this study is to elaborate on a 2-step process for mapping the magnetic field of a compactly designed satellite. The 2-step process involves, (i) carrying out experiments in a Helmholtz cage (HHC) to obtain discrete measurements of the satellite magnetic field, and (ii) performing a Fourier analysis to extrapolate the discrete measurements into a continuous map. A tri-axial HHC with precision magnetometers is set up to facilitate the measurement of magnetic field of CubeSat components - permanent magnets, magnetic torquers, etc, in a three dimensional (3D) space. Upon satisfactory calibration of the HHC, an electromagnet emulating a CubeSat magnetic torquer is placed on a rotating platform inside the HHC. The HHC is pre-configured to negate the effect of Earth's magnetic field. Using a DC supply as a power source, various intensities of currents are passed through the torquers. For various values of the current flowing through the torquers, precision magnetometers are used to measure the magnetic field generated by the torquers. The discrete magnetometer measurements are used in a Fourier analysis to develop continuous maps of magnetic fields. The magnetic maps, thus developed, facilitate an understanding of the adverse effects of satellite magnetic field on sensors, instruments. The underlying intent of the research is to investigate compensation approaches to address the adverse effects of the satellite magnetic field on its sensors and instruments.
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摘要 :
In a compactly designed satellite, particularly those hosting magnetic or electric motor based actuators, the magnetic field distribution is continuously changing and can adversely affect the sensor/instrument measurements capture...
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In a compactly designed satellite, particularly those hosting magnetic or electric motor based actuators, the magnetic field distribution is continuously changing and can adversely affect the sensor/instrument measurements captured for attitude/orbit computations or science data collection. The purpose of this study is to elaborate on a 2-step process for mapping the magnetic field of a compactly designed satellite. The 2-step process involves, (i) carrying out experiments in a Helmholtz cage (HHC) to obtain discrete measurements of the satellite magnetic field, and (ii) performing a Fourier analysis to extrapolate the discrete measurements into a continuous map. A tri-axial HHC with precision magnetometers is set up to facilitate the measurement of magnetic field of CubeSat components - permanent magnets, magnetic torquers, etc, in a three dimensional (3D) space. Upon satisfactory calibration of the HHC, an electromagnet emulating a CubeSat magnetic torquer is placed on a rotating platform inside the HHC. The HHC is pre-configured to negate the effect of Earth's magnetic field. Using a DC supply as a power source, various intensities of currents are passed through the torquers. For various values of the current flowing through the torquers, precision magnetometers are used to measure the magnetic field generated by the torquers. The discrete magnetometer measurements are used in a Fourier analysis to develop continuous maps of magnetic fields. The magnetic maps, thus developed, facilitate an understanding of the adverse effects of satellite magnetic field on sensors, instruments. The underlying intent of the research is to investigate compensation approaches to address the adverse effects of the satellite magnetic field on its sensors and instruments.
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摘要 :
In a compactly designed satellite, particularly those hosting magnetic or electric motor based actuators, the magnetic field distribution is continuously changing and can adversely affect the sensor/instrument measurements capture...
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In a compactly designed satellite, particularly those hosting magnetic or electric motor based actuators, the magnetic field distribution is continuously changing and can adversely affect the sensor/instrument measurements captured for attitude/orbit computations or science data collection. The purpose of this study is to elaborate on a 2-step process for mapping the magnetic field of a compactly designed satellite. The 2-step process involves, (i) carrying out experiments in a Helmholtz cage (HHC) to obtain discrete measurements of the satellite magnetic field, and (ii) performing a Fourier analysis to extrapolate the discrete measurements into a continuous map. A tri-axial HHC with precision magnetometers is set up to facilitate the measurement of magnetic field of CubeSat components - permanent magnets, magnetic torquers, etc, in a three dimensional (3D) space. Upon satisfactory calibration of the HHC, an electromagnet emulating a CubeSat magnetic torquer is placed on a rotating platform inside the HHC. The HHC is pre-configured to negate the effect of Earth's magnetic field. Using a DC supply as a power source, various intensities of currents are passed through the torquers. For various values of the current flowing through the torquers, precision magnetometers are used to measure the magnetic field generated by the torquers. The discrete magnetometer measurements are used in a Fourier analysis to develop continuous maps of magnetic fields. The magnetic maps, thus developed, facilitate an understanding of the adverse effects of satellite magnetic field on sensors, instruments. The underlying intent of the research is to investigate compensation approaches to address the adverse effects of the satellite magnetic field on its sensors and instruments.
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The design and development of an Electrostatic Charge Generator (ECG) presented in this article is a mechanism for deployment of drag-wires of Ultra-thin Wires Drag Enhancement System (UWDES). The UWDES is a hybrid de-orbiting sys...
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The design and development of an Electrostatic Charge Generator (ECG) presented in this article is a mechanism for deployment of drag-wires of Ultra-thin Wires Drag Enhancement System (UWDES). The UWDES is a hybrid de-orbiting system being developed for nano/micro-satellites in low/medium altitude Earth orbits. The ECG on-board the UWDES accomplishes electrostatic charging of drag wires on command. Here, it is preferred to charge the drag wires positively as altitudes of target spacecraft, which lie in the inner Van Allen radiation belt, are dominant of positive charges. For this purpose, the spacecraft bus voltage is stepped up to high potentials of 10 kV - 15 kV DC. This is supplied to an anode-cathode setup constituting the charge transfer mechanism, which works on the principle of field electron emission, to remove electrons from the wires, thereby charging it positively. The emitted electrons are collected and supplied to the spacecraft ground. The ECG and its related circuitry are designed for implementation on a circuit board, which will be housed within a hermetically sealed case of the UWDES. The design, simulation, construction and testing of ECG for experimental validation is reported here. We find that the high voltage generation system consisting of a DC - DC voltage multiplier circuit with AC link provides a robust method to achieve the desired high potentials. A grid like structure for anode and needle like structure for cathode is designed for the field emission to facilitate charge transfer. Alongside, the regulation and distribution will be taken care by an on-board electron gun and the spacecraft ground.
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摘要 :
The design and development of an Electrostatic Charge Generator (ECG) presented in this article is a mechanism for deployment of drag-wires of Ultra-thin Wires Drag Enhancement System (UWDES). The UWDES is a hybrid de-orbiting sys...
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The design and development of an Electrostatic Charge Generator (ECG) presented in this article is a mechanism for deployment of drag-wires of Ultra-thin Wires Drag Enhancement System (UWDES). The UWDES is a hybrid de-orbiting system being developed for nano/micro-satellites in low/medium altitude Earth orbits. The ECG on-board the UWDES accomplishes electrostatic charging of drag wires on command. Here, it is preferred to charge the drag wires positively as altitudes of target spacecraft, which lie in the inner Van Allen radiation belt, are dominant of positive charges. For this purpose, the spacecraft bus voltage is stepped up to high potentials of 10 kV - 15 kV DC. This is supplied to an anode-cathode setup constituting the charge transfer mechanism, which works on the principle of field electron emission, to remove electrons from the wires, thereby charging it positively. The emitted electrons are collected and supplied to the spacecraft ground. The ECG and its related circuitry are designed for implementation on a circuit board, which will be housed within a hermetically sealed case of the UWDES. The design, simulation, construction and testing of ECG for experimental validation is reported here. We find that the high voltage generation system consisting of a DC - DC voltage multiplier circuit with AC link provides a robust method to achieve the desired high potentials. A grid like structure for anode and needle like structure for cathode is designed for the field emission to facilitate charge transfer. Alongside, the regulation and distribution will be taken care by an on-board electron gun and the spacecraft ground.
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A multi-band spectrometer onboard a nano/micro-class CubeSat is a cost-effective solution to create spectral maps of G-H gases from space. Such maps would be critical in identifying regions with high concentrations of G-H gases an...
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A multi-band spectrometer onboard a nano/micro-class CubeSat is a cost-effective solution to create spectral maps of G-H gases from space. Such maps would be critical in identifying regions with high concentrations of G-H gases and addressing the risk associate with such exposure. The article presents the design and simulation of a dual-band (infrared and ultraviolet - IR and UY) imaging spectrometer for nano/micro-class CubeSat applications. By using multi-spectral imaging systems, we can measure broad spectral signatures. The design study is conducted for two basic configurations. The irradiance map and surface relief maps reveals the efficiency of this system. The design of the dual-band spectrometer is constrained by the size, weight and power limitations of the CubeSat form factor.
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