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What Are Rockets?
Published in Travis S. Taylor, Introduction to Rocket Science and Engineering, 2017
Currently, the ESA has the Ariane 5 and the Soyuz launch vehicles. The Ariane 5 is truly an ESA vehicle, whereas the Soyuz is purchased from the Russians. Figure 1.17 shows the details of the Ariane 5. More details of the Soyuz will be discussed in Section 1.2.7. It should also be noted that the ESA is developing a launch vehicle called Vega in cooperation with the Italian Space Agency. The Vega rocket is expected to be a single-body launcher with three solid stages and one upper liquid stage. It should be noted that CNES is also a partner with the Ariane 5 launch vehicle, and it is its primary vehicle as well.
Microwave and combustion methods: a comparative study of synthesis, characterization, and applications of NiO nanoparticles
Published in Inorganic and Nano-Metal Chemistry, 2023
S. Pramila, V. Lakshmi Ranganatha, G. Nagaraju, C. Mallikarjunaswamy
A Field Emission Scanning Electron Microscope (FE-SEM) was used to examine the surface morphology of NiO nanoparticles produced by microwave and solution combustion methods. Besides, an energy-dispersive X-ray spectrometer (TESCAN Vega 3LMU) is used to analyze the chemical composition of the nanoparticles. Further, Powder X-ray diffraction (P-XRD) patterns were recorded using Rigaku smart lab diffractometer with Cu-Kα radiation (1.5418) for the microstructural analysis. Whereas the functional groups present in the NiO nanoparticles were identified by Fourier Transform Infrared spectrometer (FTIR) between the wavelengths of 4000–400 cm−1. The optical property and dye concentrations were also studied by using Agilent Cary 60 UV–Vis spectrophotometer with a reflection mode of 200–800 nm wavelength. Photodegradation experiments were conducted by using Heber visible annular type photoreactor.
Plasma Waves Around Comets
Published in IETE Technical Review, 2022
The erstwhile USSR launched Vega-1 and Vega-2 within a week in December 1984 to Venus and then onto an encounter with comet Halley. In fact, Vega-1 was the first spacecraft to reach comet Halley at a closest approach of 8890 km. Later, Vega-2 also reached comet Halley (only second spacecraft to do so) but approached the comet at a closer distance than Vega-1 at 8030 km [40,41]. Vega-1 and Vega-2 were identical spacecrafts with magnetometer (MISCHA, Magnetic field in Interplanetary Space during Comet Halley’s Approach) [42], low-frequency plasma-wave analyzer (APV-N), high-frequency plasma-wave analyzer (APV-V) onboard for plasma and wave studies. APV-N was designed to measure the low-frequency electric field in two channels –0–0.5 Hz and 0.1–8 Hz while APV-V was designed to measure the electric field in range 8 Hz–300 kHz using 16 frequency filters with an 11 m baseline dipole antenna [43].
Evolutionary system design using a generalized component–resource model
Published in Engineering Optimization, 2021
Matthew L. Marcus, Raymond J. Sedwick
The CR optimization problem can be stated as follows: find the combination of allowable components and system-level design variables that optimize objective performance while meeting all required resource flows, ensuring proper functioning of the system. Formally, where each is a surplus constraint and each is a deficit constraint as described above, and each and is a constant constraining the corresponding resource. M and N are the total number of surplus and deficit constraints, respectively. is the set of all components comprising an individual design, and is the vector of system-level variables beyond component selection. is the objective function, which varies with the specific design problem. A specialized GA, the Vehicle Encoding GA (VEGA) was developed to perform this optimization. The ‘vehicle’ reference alludes to the eventual intention to use VEGA to optimize spacecraft designs.