Plume Characterization of Busek 600W Hall Thruster

The BHT-600W thruster has a high potential to place on various commercial and military satellites as a main propulsion system for orbit maintenance and orbit maneuvering. Therefore, the thruster\u27s performance characteristics and parameters were evaluated for various operating conditions. These parameters include thrust, power consumption, mass flow rate, and efficiencies. Various plume properties were measured and characterized for the thruster to include exhaust beam profile and ion species distribution. The faraday probe was used to examine the thruster plume current density while the ion species fractions were determined by the ExB probe. The inverted pendulum thrust stand was also utilized to determine the thrust performance of the thruster. This research determined optimal performance for this thruster was lower but closed to values stated by Busek Co. The measured values were 34.8+-1.3 mN of thrust, 1,267+-39s specific impulse, and had a measured propulsive efficiency of 36.2+-2.4 %. Last, beam efficiency from Faraday probe measurements yielded 52.1+-0.27%. Charge exchanges were observed to appear around 40o divergence angles. Higher charge ion species were found to dominate with increasing discharge voltage. Lastly, there were minimal effects of magnet currents on thruster\u27s performance. The results from the research will hopefully be of use in future developments and will contribute to operational applications. This research could potentially be used to improve or confirm numerical models, help to develop future designs, and improve comparison of experimentation with on-orbit plume simulations

Vai trò của nhóm nghiên cứu đối với việc công bố quốc tế trong lĩnh vực khoa học tự nhiên và kỹ thuật

Công bố khoa học được xem là một trong những thước đo trình độ phát triển khoa học công nghệ và sức cạnh tranh của mỗi một quốc gia do đó nó luôn là chủ đề gây chú ý đối với toàn xã hội trong những năm gần đây. Nâng cao số lượng và chất lượng nghiên cứu khoa học, công bố quốc tế được xem là một trong những yếu tố quan trọng quyết định đến sự hình thành và phát triển của các nhóm nghiên cứu cũng như quyết định cho sự thành công của các hoạt động khoa học công nghệ của bất kỳ cơ quan tổ chức nghiên cứu, giáo dục nào. Nghiên cứu này được thực hiện nhằm đánh giá vai trò của các nhóm nghiên cứu đối với việc công bố quốc tế riêng trong lĩnh vực khoa học tự nhiên và kỹ thuật

Implementation of a new Layer-Subroutine for fractional sediment transport in SISYPHE

Water Qualit

Numerical simulation of scour development due to submerged horizontal jet

River engineeringNumerical modelling in river engineerin

A 3D numerical model of graded sediment transport in nonequilibrium condition

Proceedings of the Seventh International Conference on Hydroscience and Engineering, Philadelphia, PA, September 2006. http://hdl.handle.net/1860/732The computer code FAST3D has been developed to calculate flow and sediment transport in open channels. In the code the flow field is calculated by solving the full Reynolds-averaged Navier-Stokes equations with k- ε turbulence model; the bed-load transport is simulated with a non-equilibrium model containing an important parameter the so-called non-equilibrium adaptation length, which characterizes the distance for sediment to adjust from a non-equilibrium state to an equilibrium state; the bed deformation is obtained from an overall mass-balance equation for sediment transport. The governing equations are solved numerically with a finitevolume method on an adaptive, non-staggered grid. The former model assumed uniform bed material. In order to take into account the influence of grain size distribution of the bed-surface on the evolution of the bed topography and consequently also on the flow field, a sediment transport module has been presently developed at the Institute of Hydraulic Engineering, University of Innsbruck, Austria, for fractional sediment transport using a multiple layer model. This paper presents the numerical results for sediment sorting and the bed deformation in a curved alluvial channel under unsteady flow conditions according to Yen and Lee (1995). The calculations were compared with data from laboratory measurements. Further, the sensitivity of the simulated results to the non-equilibrium adaptation length is investigated

Numerical Modelling of Sediment Transport at Weirs

Hydrodynamic

Neural network based patient recovery estimation of a PAM-based rehabilitation robot

Rehabilitation robots have shown a promise in aiding patient recovery by supporting them in repetitive, systematic training sessions. A critical factor in the success of such training is the patient’s recovery progress, which can guide suitable treatment plans and reduce recovery time. In this study, a neural network-based approach is proposed to estimate the patient’s recovery, which can aid in the development of an assist-as-needed training strategy for the gait training system. Experimental results show that the proposed method can accurately estimate the external torques generated by the patient to determine their recovery. The estimated patient recovery is used for an impedance control of a 2-DOF robotic orthosis powered by pneumatic artificial muscles, which improves the robot joint compliance coefficients and makes the patient more comfortable and confident during rehabilitation exercises

Language independent transfer of assembly knowledge

Transferring assembly knowledge for workers with different cultural and linguistic background is challenging. The established solution of translating written instructions into multiple languages is mostly cost intensive, holds a potential for mistakes and the result might be hard to understand. To cope with this challenge, three different assembly instructions with language reduced or language independent content have been tested in a study with students in Vietnam and Germany. The types of instructions were interactive 3D-PDF, Utility-Film and illustrated manual. Assembly errors, assembly time, safety symbol awareness and assembly sequences understanding are compared and evaluated based on students’ technical pre-knowledge and experience. The 3D-PDF showed to be the best solution to be applied in this complex environment, because users were able to assemble the parts faster and experienced a higher degree of interactivity compared to the other instructions