• Title/Summary/Keyword: Static attitude control

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Design modification and structural behavior study of a CFRP star sensor baffle

  • Vinyas, M.;Vishwas, M.;Venkatesha, C.S.;Rao, G. Srinivasa
    • Advances in aircraft and spacecraft science
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    • v.3 no.4
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    • pp.427-445
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    • 2016
  • Star sensors are the attitude estimation sensors of the satellite orbiting in its path. It gives information to the control station on the earth about where the satellite is heading towards. It captures the images of a predetermined reference star. By comparing this image with that of the one captured from the earth, exact position of the satellite is determined. In the process of imaging, stray lights are eliminated from reaching the optic lens by the mechanical enclosures of the star sensors called Baffles. Research in space domain in the last few years is mainly focused on increased payload capacity and reduction in launch cost. In this paper, a star sensor baffle made of Aluminium is considered for the study. In order to minimize the component weight, material wastage and to improve the structural performance, an alternate material to Aluminium is investigated. Carbon Fiber Reinforced Polymer is found to be a better substitute in this regard. Design optimisation studies are carried out by adopting suitable design modifications like implementing an additional L-shaped flange, Upward flange projections, downward flange projections etc. A better configuration of the baffle, satisfying the design requirements and achieving manufacturing feasibility is attained. Geometrical modeling of the baffle is done by using UNIGRAPHICS-Nx7.5(R). Structural behavior of the baffle is analysed by FE analysis such as normal mode analysis, linear static analysis, and linear buckling analysis using MSC/PATRAN(R), MSC-NASTRAN(R) as the solver to validate the stiffness, strength and stability requirements respectively. Effect of the layup sequence and the fiber orientation angle of the composite layup on the stiffness are also studied.

A Study on Health Belief and Health Behaviors of the Elderly (노인의 건강신념과 건강관행에 관한 연구)

  • Wang, Myoung-Ja;Cha, Nam-Hyun
    • Journal of East-West Nursing Research
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    • v.8 no.1
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    • pp.103-112
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    • 2003
  • This paper focused on providing the groundwork for the development of proper nursing interventions to enhance the quality of life for the elderly by identifying the factors that may affect their health beliefs and behaviors. A survey was conducted on a group of people aged between 60 and 86 years residing in S and K cities from January to March of 2003, who agreed to participate in the research. Data was collected using instruments measuring health beliefs and health behaviors, and was analyzed by using SPSS. The results of this study are as follow. 1) Those in the group were aged between60 and 86 years, and the average age was 66.94 years old. Most of them were living together with their spouses. From the survey, 83.5% replied "above average" on the question regarding their current health condition, whereas, 46.0% mentioned that they had some sort of diseases. 2) Overall average score of the health belief was 516.05, with a mean $3.71{\pm}4.07$. This indicates that the studied group held a high level of health belief, which affects their attitude and intention to lead a healthy life by placing the present life under control in harmony with nature. 3) Overall average score of the health behaviors was 392.24 with a mean $2.82{\pm}.52$. For health purposes, the behaviors that the elderly people were taking were mostly static ones requiring a low level of activity. The analysis showed that they generally were involved in self-trained, individualized health care. Thus, the elderly place a higher priority on regular dietary behaviors than on physical activity. 4) The correlation between health belief, a cognitive aspect on health, and health behaviors, a behavioral aspect showed a very high linear relationship (r=.520, p<.000). Consequently, it is found that those who have higher cognitive health belief are involved in higher level of behavioral health practice. These findings concluded that the Korean elderly have good health beliefs, well controlling their minds and being harmonious with nature. Health behaviors that they are engaged in are mostly static, requiring low level activity, while they place higher priority on regular dietary habits and conducting self-trained individualized health care. Important factor affecting their health beliefs and health behaviors was found to be their health practice. Since higher health belief is highly related with good health behaviors, development of health activity programs is in need as a means for an efficient health improvement, where motivating environment may be established to enhance the health belief of the elderly and to satisfy individual values.

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