• Title/Summary/Keyword: regularity effect

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The aerostatic response and stability performance of a wind turbine tower-blade coupled system considering blade shutdown position

  • Ke, S.T.;Xu, L.;Ge, Y.J.
    • Wind and Structures
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    • v.25 no.6
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    • pp.507-535
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    • 2017
  • In the strong wind shutdown state, the blade position significantly affects the streaming behavior and stability performance of wind turbine towers. By selecting the 3M horizontal axis wind turbine independently developed by Nanjing University of Aeronautics and Astronautics as the research object, the CFD method was adopted to simulate the flow field of the tower-blade system at eight shutdown positions within a single rotation period of blades. The effectiveness of the simulation method was validated by comparing the simulation results with standard curves. In addition, the dynamic property, aerostatic response, buckling stability and ultimate bearing capacity of the wind turbine system at different shutdown positions were calculated by using the finite element method. On this basis, the influence regularity of blade shutdown position on the wind-induced response and stability performance of wind turbine systems was derived, with the most unfavorable working conditions of wind-induced buckling failure of this type of wind turbines concluded. The research results implied that within a rotation period of the wind turbine blade, when the blade completely overlaps the tower (Working condition 1), the aerodynamic performance of the system is the poorest while the aerostatic response is relatively small. Since the influence of the structure's geometrical nonlinearity on the system wind-induced response is small, the maximum displacement only has a discrepancy of 0.04. With the blade rotating clockwise, its wind-induced stability performance presents a variation tendency of first-increase-then-decrease. Under Working condition 3, the critical instability wind speed reaches its maximum value, while the critical instability wind speed under Working condition 6 is the smallest. At the same time, the coupling effect between tower and blade leads to a reverse effect which can significantly improve the ultimate bearing capacity of the system. With the reduction of the area of tower shielded by blades, this reverse effect becomes more obvious.

Experimental study on models of cylindrical steel tanks under mining tremors and moderate earthquakes

  • Burkacki, Daniel;Jankowski, Robert
    • Earthquakes and Structures
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    • v.17 no.2
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    • pp.175-189
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    • 2019
  • The aim of the study is to show the results of complex shaking table experimental investigation focused on the response of two models of cylindrical steel tanks under mining tremors and moderate earthquakes, including the aspects of diagnosis of structural damage. Firstly, the impact and the sweep-sine tests have been carried out, so as to determine the dynamic properties of models filled with different levels of liquid. Then, the models have been subjected to seismic and paraseismic excitations. Finally, one fully filled structure has been tested after introducing two different types of damages, so as to verify the method of damage diagnosis. The results of the impact and the sweep-sine tests show that filling the models with liquid leads to substantial reduction in natural frequencies, due to gradually increasing overall mass. Moreover, the results of sweep-sine tests clearly indicate that the increase in the liquid level results in significant increase in the damping structural ratio, which is the effect of damping properties of liquid due to its sloshing. The results of seismic and paraseismic tests indicate that filling the tank with liquid leads initially to considerable reduction in values of acceleration (damping effect of liquid sloshing); however, beyond a certain level of water filling, this regularity is inverted and acceleration values increase (effect of increasing total mass of the structure). Moreover, comparison of the responses under mining tremors and moderate earthquakes indicate that the power amplification factor of the mining tremors may be larger than the seismic power amplification factor. Finally, the results of damage diagnosis of fully filled steel tank model indicate that the forms of the Fourier spectra, together with the frequency and power spectral density values, can be directly related to the specific type of structural damage. They show a decrease in the natural frequencies for the model with unscrewed support bolts (global type of damage), while cutting the welds (local type of damage) has resulted in significant increase in values of the power spectral density for higher vibration modes.

The Effect of Departmental Accounting Practices on Organizational Performance: Empirical Evidence from the Hospital Sector in India

  • MISHRA, Nidhish Kumar;ALI, Ijaz;SENAN, Nabil Ahmed Mareai;UDDIN, Moin;BAIG, Asif;KHATOON, Asma;IMAM, Ashraf;KHAN, Imran Ahmad
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.4
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    • pp.273-285
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    • 2022
  • Using data from a departmental profit and loss management questionnaire survey conducted for a group of hospitals consisting of various establishment entities, this study evaluates the effectiveness of departmental profit and loss management practices, such as break-even analysis, based on objective performance data. The study also examines whether the implementation of departmental profit and loss accounting is still effective in improving profitability in the financial year 2021 and whether the effectiveness of the implementation of departmental profit and loss accounting is robust. This study reconfirmed that the implementation of departmental profit-and-loss accounting has a positive effect on objective financial performance in hospitals and that the effect of improving profitability can be enhanced by implementing it monthly with high frequency and regularity and by using the accounting results more actively. It was also found that the department's implementation of break-even analysis had a positive impact on financial performance, which was enhanced by more active use of the data. Given the current economic climate, a hospital organization's active participation in income statement management, not only for the hospital as a whole but also for each department, would be an effective management activity.

Effect of Majoon Idraare Haiz in Polycystic Ovarian Syndrome - A pilot study

  • Firdose, Kouser fathima;Begum, Wajeeha
    • CELLMED
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    • v.12 no.1
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    • pp.3.1-3.7
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    • 2022
  • Background & Objectives: Polycystic ovarian syndrome (PCOS) is one of the commonest endocrine abnormality in women of reproductive age affecting from 4% - 21% of the reproductive women and is characterized by chronic anovulation and hyperandrogenism. The aim of the study was to evaluate the effect of majoon idraare haiz in menstrual regulation and morphological changes in ovaries in poly cystic ovarian syndrome. Methods: A Pilot study was carried out in the department of Ilmul qabalat wa amraze niswan, National institute of unani medicine, hospital, Bengaluru. Fifteen Patients of PCOS aged 18-35 diagnosed using Rotterdam criteria were included in the study. Patients with insulin sensitizing treatment within 3 months, hormonal treatment and those with h/o diabetes mellitus, hypertension, pregnant and lactating women were excluded.Majoon idraare haiz was administered orally at a dose of 10 g with 20 ml arqbed mushk once daily from fifth day of cycle for 21 days for three consecutive cycles. Primary outcome measure was menstrual regularity while changes in USG pelvis(normal ovarian morphology) was considered as secondary outcome measure. In addition, duration of flow and changes in basal metabolic index (BMI), modified Ferriman Gallwey (mFG) score, acanthosis nigricanswere observed. Data were analyzed using, ANOVA, paired student 't' test, fisher exact test. Results: Changes in duration of cycle, duration and amount of flow was achieved in 93.3% patients with p<0.0001 and 46.6% patients showed normal findings on pelvic ultrasonography with p=0.006. In addition, significant changes were also observed in BMI, hirsutism and acanthosis nigricans with p value of 0.0001, p=0.003 and p=0.009 respectively Conclusion: Majoonidraare haiz can be used as an effective alternative in management of PCOS patients. It has significant effect on menstrual regulation and changes in polycystic ovarian morphology to normal.

Effect of MgB6 Addition on Synthesis of Hexagonal Boron Nitride (Hexagonal Boron Nitride의 합성에 있어서 MgB6 첨가의 효과)

  • Lee, Dae-Jin;Jee, Mi-Jung;Choi, Byung-Hyun;Lee, Mi-Jai;Cho, Nam-Hee;Cha, Mi-Sun
    • Journal of the Korean Ceramic Society
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    • v.46 no.1
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    • pp.53-57
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    • 2009
  • The h-BN powder was synthesized by amorphous $B_2O_3$ and activated carbon at $1550^{\circ}C$ in nitrogen atmosphere, whose properties were examined according to $MgB_6$ addition. Amount of $MgB_6$ addition was varied in the range of $0{\sim}$10\;wt% of the initial mixture. It was observed that $MgB_6$ addition led to an increase in the amount and the grain size of h-BN and decrease in the amount of $B_4C$ forming. When $MgB_6$ added 5 wt%, the amount and crystallinity of h-BN increased as the holding time at the synthesis temperature was prolonged. It was also confirmed that the regularity of three-dimensional ordering of h-BN increases.

The Effect of Human Resource Development on Employed Workers' Job Satisfaction and Wage (남녀직장인의 인적자원개발이 직무만족과 임금수준에 미치는 영향)

  • Kwak, In-Sook;Hong, Sung-Hee
    • Journal of Families and Better Life
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    • v.26 no.1
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    • pp.107-120
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    • 2008
  • The purpose of this study was to analyze the effects of human resource development on the job satisfaction and wage among employed workers. A sample of 3,578 employed workers was selected from Korea Labor Panel Data. For data analysis, t-test and multiple regression were used. The major findings were as follows: First, the employed workers who had experiences of human resource development had more certificates of job-related qualification, more employed in government-invested organization or foreign company regularly than the counterpart. Second, the employed workers' wage was affected by gender, age, educational attainment, as well as whether they had experiences of human resource development. Third, the factors that influence employed workers' job satisfaction were gender, age, educational attainment, job regularity, having certificate of job-related qualification or not, and having experiences of human resource development or not. From the findings, it can be concluded that the employed workers' wage and job satisfaction were improved by the human resource development.

The Dietary Behavior and Food Preference according to Personality Types of High School Students in Gyeongju (경주지역 고등학생의 성격유형에 따른 식생활 태도 및 식품기호도)

  • 유지은;유두련;박금순
    • Journal of the East Asian Society of Dietary Life
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    • v.13 no.5
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    • pp.371-378
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    • 2003
  • The purpose of this study was to investigate the dietary behavior and food preference based on the personality types of the high school students in Gyeongju. According to the survey on the personality types of the students, the type of SP(Sensing-perceiving) occupied the highest ratio, 46% and NF(Intuition-Feeling) 8.6% and NT(Intuition-Thinking) 8.2% and SJ(Sensing-Judging) 7.1%. The difference between the ratio of SP(Sensing-perceiving) and NF was the highest. There was a difference according to the personality types in the effect of knowledge learned in school on the choice of food; the types of NT and NF did not influence on it. The degree of regularity in the amount of every meal showed a significant difference according to the personality types (p<.05); students with NT and SJ types had the regular meals. The factors which could influence on the dietary behavior were parents(60.7%), friends(16.9%) and mass media and books(13.8%), etc. School education had a little influence on the dietary behavior, only 8.0%. Therefore, more practical education was needed. In the food preference, the type of NF preferred the foods with sweet taste while the others with hot taste.

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Job Characteristics and Poverty Status of Working Poor -Sex Differences- (근로빈곤층의 일자리 특성과 빈곤 지위 - 성별 비교를 중심으로-)

  • Kim, Eun-Ha
    • Korean Journal of Social Welfare
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    • v.60 no.4
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    • pp.5-29
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    • 2008
  • The purpose of this study is to investigate the effect of job characteristics of working poor on poverty status, focused on sex differences. The results are as follows. First, there are sex differences in career year, job position and industry for determining poverty entry. And second, career year, job regularity and occupy are different variables for men and women in determining poverty exit. This result says that job characteristics partially affects on poverty status of sex differently. Thus we need to sensitive policy that considers different experiences of men and women working poor as to poverty status mobility.

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Maternal Perception of Children's Temperament & Parenting Stress (어머니가 지각한 유아의 기질과 양육 스트레스)

  • Jo, Yeong-Shin;Chong, Young-Sook
    • Korean Journal of Human Ecology
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    • v.9 no.3
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    • pp.271-281
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    • 2000
  • The purpose of this study was to explore the effect of maternal perception of children's temperament on parenting stress. The subjects of this study were 303 mothers of four to six-year-old. Evaluations of Parent and Teacher temperament questionnaire for Children 3-7 years of age(Tomas, Chess, & Kom, 1977)(korean version) was used to measure children's temperament, and PDH(Parenting Daily Hassles) was used to measure maternal perception of parenting stress. Data were analyzed by descriptive analysis, t-test, ANOVA, Peasons's Correlation and multiple regression analysis and Duncan test for post test by SPSS WIN program. The results of this study were as follows; First, the average level of maternal perception of children's temperament was the highest in the category of adaptability and the lowest in the category of threshold of responsiveness. Second, maternal perception of children's temperament was significantly different according to children's sex. Boys were perceived higher than girls for the category of activity level. Third, the degree of daily hassles was explained by adaptability, the quality of mood, and activity level relatively, while the intensity of parenting stress could be predicted orderly by adaptability, threshold of responsiveness, attention span & persistence, regularity, and activity level. Fourth, mother's daily hassles was explained 22% valiance by children's temperament such as adaptability, the quality of mood, and activity level. Future research should be done to identify the interaction of temperamental factors.

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A study on the effects of vertical mass irregularity on seismic performance of tunnel-form structural system

  • Mohsenian, Vahid;Nikkhoo, Ali
    • Advances in concrete construction
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    • v.7 no.3
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    • pp.131-141
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    • 2019
  • Irregular distribution of mass in elevation is regarded as a structural irregularity by which the modes with high energy levels are excited and in addition, it can lead the structure to withstanding concentration of nonlinear deformations and consequently, suffer from unpredictable local or global damages. Accordingly, with respect to the lack of knowledge and insight towards the performance of concrete buildings making use of tunnel-form structural system in seismic events, it is of utmost significance to assess seismic vulnerability of such structures involved in vertical mass irregularity. To resolve such a crucial drawback, this papers aims to seismically assess vulnerability of RC tunnel-form buildings considering effects of irregular mass distribution. The results indicate that modal responses are not affected by building's height and patterns of mass distribution in elevation. Moreover, there was no considerable effect observed on the performance levels under DBE and MCE hazard scenarios within different patterns of irregular mass distribution. In conclusion, it appears that necessarily of vertical regularity for tunnel-form buildings, is somehow drastic and conservative at least for the buildings and irregularity patterns studied herein.