• Title/Summary/Keyword: Work Capacity

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Analytical study of the failure mode and pullout capacity of suction anchors in sand

  • Liu, Haixiao;Peng, Jinsong;Zhao, Yanbing
    • Ocean Systems Engineering
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    • v.5 no.4
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    • pp.279-299
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    • 2015
  • Suction anchors are widely adopted and play an important role in mooring systems. However, how to reliably predict the failure mode and ultimate pullout capacity of the anchor in sand, especially by an easy-to-use theoretical method, is still a great challenge. Existing methods for predicting the inclined pullout capacity of suction anchors in sand are mainly based on experiments or finite element analysis. In the present work, based on a rational mechanical model for suction anchors and the failure mechanism of the anchor in the seabed, an analytical model is developed which can predict the failure mode and ultimate pullout capacity of suction anchors in sand under inclined loading. Detailed parametric analysis is performed to explore the effects of different parameters on the failure mode and ultimate pullout capacity of the anchor. To examine the present model, the results from experiments and finite element analysis are employed to compare with the theoretical predictions, and a general agreement is obtained. An analytical method that can evaluate the optimal position of the attachment point is also proposed in the present study. The present work demonstrates that the failure mode and pullout capacity of suction anchors in sand can be easily and reasonably predicted by the theoretical model, which might be a useful supplement to the experimental and numerical methods in analyzing the behavior of suction anchors.

Performance Characteristics of a Mixed Refrigerant OTEC Power Cycle Using Hot Waste Water (온배수를 이용한 혼합냉매용 해양온도차 발전 사이클의 성능 특성)

  • Yoon, Jung-In;Son, Chang-Hyo;Heo, Jeong-Ho;Ye, Byoung-Hyo;Kim, Hyun-Ju;Lee, Ho-Saeng
    • Journal of Power System Engineering
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    • v.17 no.6
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    • pp.102-107
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    • 2013
  • In this paper, the performance analysis for evaporation capacity, total work and efficiency of the ocean thermal energy conversion(OTEC) power system using mixed refrigerant(R32,R152a) is conducted to find the effect of hot wasted water on OTEC power system. The system in this study is applied with two stage turbine, regenerator, cooler and separator on Organic Rankine Cycle. The commercial program HYSYS is used for the performance analysis. The main results were summarized as follows : The efficiency of the OTEC power cycle has a largely effect on the evaporation capacity and total work. As increasing temperature of heat source water, evaporator's capacity is decreased but total work increase. Otherwise, using hot wasted water bring effects not only increasing system efficiency but also declining evaporator's capacity. Thus With a thorough grasp of these effect, it is necessary to find way to use hot wasted water emitted by power plant and so on.

Organizational Capacity and Performance of Local Public Health in Korea (지역공공보건조직의 역량과 조직성과)

  • Kim, Jae Hee
    • Journal of agricultural medicine and community health
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    • v.41 no.4
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    • pp.183-194
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    • 2016
  • Objectives: The purpose of this study was to investigate the differences of capacity of local health organization to regional characteristics and the influence of organizational capacity on organizational performance. Methods: The study used the secondary data for 160 local public health organizations from $5^{th}$ Community Health Plans and 2009 Community Health Survey. The collected data were analyzed using one-way ANOVA and multiple regression analysis. Results: Work force and budget showed differences in regional size and elderly population rate. And consumer satisfaction and health care utilization showed differenced in work force and budget. The regression model with total number of employee, number of registered nurses, number of doctors and budget against consumer satisfaction was statistically significant (F=14.70, p=<.001), and number of registered nurses was identified as a factor influencing consumer satisfaction. This model also explained 20.5% of service satisfaction. The regression model for consumer satisfaction was statistically significant (F=45.98, p=<.001), and total number of employee nurses was identified as a factor influencing health care utilization. This model also explained 53.1% of utilization. Conclusions: The findings of this study imply that organizational capacity as work force and budget should be increased to improve the organizational performance as consumer satisfaction and health care utilization.

The Fundamental Research on Lifting-Work for Excavator Safety Management (굴삭기 안전 관리를 위한 인양작업에 관한 기초연구)

  • Lee, Yongsu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.6D
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    • pp.811-818
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    • 2011
  • Though an excavator is classified as an equipment utilizing a shovel in earthworks, it has been frequently used in lifting work. In this view, lifting capacity is classified as the main functions of the excavator. Thus, its accurate functions need to be provided. However, in domestic conditions, the necessity for the functions of lifting capacity are not perceived. This study shows 1) Many researches about lifting-work of excavators abroad are used as basic data necessary for domestic introduction. 2) For domestic excavators without the information of lifting-work, methodologies of lifting-work available are suggested and reviewed. 3)Lifting zones are divided into safety and caution lifting zones. The information on lifting capacity and lifting zones will be able to used as objective and substantive bases to operational planning and safety management.

A Study on Job Techinique of Aquarium related Prospective Occupation in Korea (우리나라 수족관 관련 유망 직업의 직무기술에 관한 연구)

  • KIM, Sam-Kon;HA, Eun-Jong
    • Journal of Fisheries and Marine Sciences Education
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    • v.21 no.2
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    • pp.213-229
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    • 2009
  • The purpose of this study is not only to provide students in the fishery high schools with source materials and opportunity, but also to contribute to a comprehensive development in educational program of the fishery high schools. It investigated various factors of aquarium related 6 new occupations : job contents, educational-level for job performance, training period, worker's capacity, the degree of physical activity, working place, and working environment. First, the work intensity is a normal work. The physical activities such as crawling, bending, accurately seeing a nearby thing and using hands are frequently used. The work is mainly conducted inside a room. The condition for a work environment is very moist and humid. Second, the work intensity is a light work. The physical activities such as using hands, speaking and accurately seeing a nearby thing are frequently used. The work is mainly conducted inside and outside a room. The work environment factor did not have any effect on the work. Third, the work is mainly conducted inside and outside a room. The risk in the condition for a work environment is found out as miscellaneous. Fourth, the physical activities such as bending, touching, and accurately seeing a nearby thing are frequently used. The work is mainly conducted inside a room. The work environment factor did not have any effect on the work. Fifth, the work is mainly conducted inside a room. The condition for a work environment is very moist and humid. Sixth, the work is mainly conducted inside a room. The work environment factor did not have any effect on the work.

Gender differences of anaerobic capabilities in untrained adults (비훈련 성인남여의 무산소성 운동능력 차이)

  • Jeong, Jinwon
    • Journal of Digital Convergence
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    • v.16 no.5
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    • pp.463-468
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    • 2018
  • The purpose of the study was to investigate the gender differences of anaerobic capabilities between anaerobic capacity(AC) from Wingate test and anaerobic work capacity(AWC) from critical power test in untrained male and female adults. Both tests were carried out to 12 male and 13 female subjects on a Monark cycle ergometer. The results of this study demonstrated that men were higher than women in AC for the Wingate test, but no gender difference(J/kg) in AWC for the Critical Power test. There was a significant relationship between AC(J/kg) and AWC(J/kg) in women(r=0.61, p<0.05), but no significant relationship in men(r=-0.32, p>0.05). ANCOVA analyses using $VO_{2max}$ and body weight as covariates had significant influence on the AWC gender difference. The study provides preliminary data on gender differences of anaerobic capabilities.

Suppression of Strategic Capacity Withholding by Capacity Payment in a Competitive Generation Market (경쟁적 전력시장에서 용량요금에 의한 전략적 용량철회 억제)

  • Lee, Kwang-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.7
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    • pp.1199-1204
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    • 2007
  • In a cost based pool market, the generation capacity can be used as strategic bids by generation companies (Gencos) with the cost functions open to the market. Competition using strategic capacities is modeled by Cournot and Perfect Competiton (PC) model, and transformed into two by two payoff matrix game with Gencos' decision variables of Cournot and PC model. The payoff matrices vary when capacity payments are given to Gencos in accordance with their capacity bids. Nash Equilibrium (NE) in the matrices also moves with capacity price changes. In order to maximize social welfare of the market, NE should locate in a certain position of the payoff matrices, which corresponds to a PC NE. A concept of a critical capacity price is proposed and calculated in this paper that is defined as a minimum capacity price leading to PC NE. The critical capacity price is verified to work as a tool for suppressing a strategic capacity withholding in simulations of a test system.

Capacity Estimation Models for Work-zones Under Traffic Signal Influence and the Empirical Validation (신호영향권 하 도로공사구간에서의 용량산정모형 개발과 실증)

  • Shin, Chi-Hyun
    • Journal of Korean Society of Transportation
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    • v.31 no.1
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    • pp.77-86
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    • 2013
  • This paper focuses on the development of analytical models for estimating the changes in saturation flow rates (SFR) at the stop-lines of a signalized intersection due to the existence of nearby work-zones, and thereby calculating the prevailing capacity values for specific lane groups. Major changes were incorporated in the logics of previous models and significant revisions have been made to secure the accuracy and simplicity. Furthermore, much attention was paid to model validation by making comparisons to both extensive simulation results and empirical data from various sites. It was found that SFRs are highly sensitive to the location of work-zones, the distance to each work-zone from the stop-line of a concerned approach, the number of lanes open and closed, and the effective green time. Using such geometric and operating conditions that constitute work-zone environment, the proposed models successfully estimated SFR values with a miniscule margin of error.

The Effects of Individual Characteristics of IPP Work-Learning Trainees and Field Teachers of Participating Companies on Trainees' Employability - Focusing on Social Integration and Absorption Capabilities of Companies - (IPP일학습 훈련생과 참여기업 현장교사의 개인특성이 훈련생의 고용가능성에 미치는 영향 -기업의 사회적통합과 흡수역량 중심으로-)

  • Bae, Yong Il;Seo, Young Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.83-93
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    • 2019
  • The purpose of this study is to suggest implications for maximizing the effectiveness and efficiency of IPP work-learning by studying the effects of the personal characteristics of trainees and firm's field teacher on trainees' employability. The following conclusions were drawn by verifying the causal relationship between factors based on a questionnaire (157 copies) distributed to 200 trainees (learning workers) of 9 universities participating in IPP work-learning training. First, in order to increase the employability of IPP trainees, it is necessary to select trainees with strong core competencies and failure tolerance by verifying individual characteristics of trainees. Secondly, companies should appoint senior staff with strong leadership and teaching capacity as corporate field teachers, and corporate field teacher training institutions should reinforce the training to improve their leadership. Third, work-learning companies should be selected as those with high social integration and absorption capacity, and those companies should try to build an organizational culture of acquiring and learning new technologies. The results of this study are expected to contribute to enhancing the effectiveness of work-learning training by establishing a training system that can systematically select trainees and participating companies and enhance the training capacity of companies and field teachers.

Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • Hwang, Chang-Muk;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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