• 제목/요약/키워드: Opening characteristics

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Shotcrete-Retrofit of Shear Walls with an Opening (개구부를 가지는 전단벽의 숏크리트 보강)

  • Choi, Youn-Cheul;Choi, Chang-Sik;Kim, Hyun-Min;Lee, Li-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.5
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    • pp.71-80
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    • 2007
  • Because of the characteristics relating to high tensile ductility, High Performance Fiber Reinforced Cementitious Composites (HPFRCC) are studied to be adopted in repair and retrofit of buildings. A series of three shear wall specimens was tested under constant axial stress and reversed cyclic lateral loading in order to evaluate the seismic retrofit that had been proposed for the shear wall with the opening. The retrofit involved the use of newly developed ECC and MDF(Macro Defect Free), both of which are sprayed through the high pressure pump, over the entire face of the wall. The results indicate that two difference types of retrofitting strategy make the different effects of a rise in the strength and ductility of each specimen.

The study on the entry of dental technicians in the public health center for a manpower supply and demand plane (Centering around a denture insurance policy in 2012) (인력수급 대책을 위한 치과기공사의 보건지소 진출에 관한 연구 - 2012년 틀니보험화 정책을 중심으로 -)

  • Lee, Jong-Do;Kim, Jeong-Sook;Park, Kwang-Sig
    • Journal of Technologic Dentistry
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    • v.32 no.4
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    • pp.417-433
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    • 2010
  • Purpose: This study evaluated the manpower planning of dental technicians. Methods: Methods : Survey was conducted regarding subject's general characteristics, characteristics of dental technician's occupational view and working conditions, and reason to enter into branches of the public health enter. The survey sample consisted of 323 dental technicians (221 male/ 102 female). Survey was conducted for one month from August 1 to September 1 in 2010. Following results were obtained. Results: 1. Regarding general characteristics of the subjects, there was a slight male predilection with 68.4%. Subjects in their 40s occupied the highest proportion of 32.2%. Majority of subjects worked in the big cities (71.5%). Favored working places were dental laboratory (57.6%) and dental hospital or dental clinic (19.5%). Although no position is available in the public sector such as public health center or health care civil servant, 9.3% preferred working in the public health center. Public sector is more favored than 2-year technical colleges or dental supply and equipment companies. In respect to education, 57% of the subjects graduated college. 67.8% were married. Subjects who specialize in the porcelain or all-ceramic were 57.9%. With regard to current position, head of the dental laboratory was most common. 2. Following occupation characteristics were found. Economic reason took the highest proportion when deciding their occupation (39.9%) followed by gaining social experience (36.5%). Majority of the subjects (76.5%) wanted to work as dental technicians until their retirement. 71.5% pursuit to become a manager of the dental laboratory. 76.1% agreed on opening a dental technician position in the public health center. Regarding an authority to lead developing the dental technician position in the public sector, majority of the subject chose ministry of health and welfare (35.6%) and Korean dental technologist association (34.7%). Employment (average, 30%) and turnover rate (average, 36.5%) of dental technology college graduates ranged from 40% to 60%. Most important factors for the employment were practical experience (41.2%) and competency (34.4%). With regard to job satisfaction, so-so as 46.7% and satisfactory was 42.7% 3. In respect to the reason for opening a position in the public health center, 'It is needed to continue denture rogram for elderly patients' obtained the highest score (4.14 point). 'Institutional devices are required to open a position for dental technicians as a public healthcare provider' received high score (4.11 point). 4. Concerning the working conditions, 'professional knowledge is required' received the highest score (4.23) followed by 'too short maternity and parental leave' (4.21). 5. Relationship between general characteristics of the subjects and favor of working in the public health center was investigated. Significant differences were found according to the current and favored working area, favored occupation, education level, marital status, and specialty. Working in the public health center was favored by following subjects: working in mid- or small-sized cities (4.16 point, p<0.05); PhD degree-holder (4.59 point, p<0.01). 6. Among general characteristics of the subjects, significant difference of working conditions was found in the following factors: gender; working areas; favored working areas; favored working positions, and education level. Majority of subjects favored working in big cities and currently work in big cities although satisfaction was comparatively low (3.75 score). 7. Future plan to work in public health center was evaluated according to occupational characteristics. Subject's intention to work in the public healthcare center was significantly affected by opening of dental technician position, leading authority, average turnover rate, and factors affecting employment. Working in the public health care center was favored by the following subjects: Dental technicians who actively supported opening of the dental technician position (4.34 point, p<0.001); subjects who thought the Korean dental technologist association is responsible for the opening of positions in the public sector (4.26 point, p<0.001); and subjects who thought that attitude and character are important for the employment (p<0.001). 8. Concerning difference of working conditions according to the occupational characteristics, significant difference was demonstrated by factors such as a reason to choose to be a dental technician, work plan, pursuing position, responsible authority, average employment rate, and job satisfaction. High standard of working conditions was required in subjects who selected to be a dental technician for the leisure time after work (s.05 point, p<0.01), who planted to work until their marriage (4.25 point, p<0.001), and who pursuit to be a manager (3.98, p<0.05). 9. In respect to influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.068 and age affected the working condition with significant difference according to the pvalue. 10. Regarding influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.335 and work plan, opening of dental technician position in the public sector, and responsible authority had significant influence over the subject's intention to work in the public health center according to the p-value. 11. With regard to the influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.091 and reason to choose to be a dental technician, work plan, and responsible authority significantly affected subject's working conditions. Conclusion: Korean society is becoming a super-aged society according to several statistics. As aged population is rapidly increasing, national health insurance plans to cover denture for senior citizen over 75 years old from 2012. Therefore, dental technicians are urgently needed in the public health centers all over the nation. Many subjects in this study planed to work until their retirement and recognized dental technician's expertise. Ministry of health and welfare and Korean dental technologist association should co-operate each other to prepare foundation and institutional devices for dental technicians to advance into the public health center. This will improve oral health of the population. This study showed urgency of medical facilities and services which meets increasing number of aged population and welfare of the population.

Development of Basic Pants Patterns for Women in Their 20s (20대 성인여성의 팬츠원형 개발)

  • Lee, Mi Sung;Kim, Sora
    • Journal of Fashion Business
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    • v.19 no.1
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    • pp.17-33
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    • 2015
  • This study aimed to develop basic pants patterns reflecting somatotype characteristics of the women in their 20s. In order to develop basic pants patterns for women in their 20s, wearing tests were conducted. With the results of wearing tests, drafting methods were applied by using regression equation for the parts that were found to improper. For the parts where regression equation was not applicable, the results of wearing tests were applied. The results and the conclusion of development of basic pants patterns for women in their 20s were as follows. The waist height was applied for the regression equations of waist to hip length, crotch length, and knee length, and the hip circumference was applied for the regression equations of front leg opening. Also, back leg opening, front knee width and back knee width were calculated based on the front leg opening. For the waistline the ease of 2cm was added, and for the hipline the ease of 4cm was added. H/16 - 1cm was applied for the drafting of front crotch width, and H/8 was applied for the drafting of back crotch width. Pants patterns for women in their 20s on the methods mentioned above were tested for the $2^{nd}$ research wearing tests, and they received good ratings on the items and demonstrated that the developed pants patterns had excellent body fit.

Performance Characteristics of an Electronically Controlled EGR Valve for Diesel Engines (디젤엔진용 전자식 EGR 밸브의 성능 특성)

  • Chung, Jin-Eun;Chin, Young-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.2
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    • pp.185-188
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    • 2007
  • Lately, the modulated EGR system that includes EGR valve and EGR cooler is being installed in diesel engines fur the purpose of the simultaneous reduction of NOx and PM. In this study. we designed and constructed a test bench for the performance evaluation of the modulated EGR system, and tested an electronically controlled EGR valve for 2.0 L diesel engines. The performance of the EGR valve was evaluated in terms of the valve lift behavior. the valve opening/closing response, and the mass flow rate through the valve. The valve lift with respect to the duty ratio of PWM signal was non-linear, and followed a different path fur valve opening and closing, that is, hysteresis. The valve opening response was concluded satisfactory falling within the usual standard response time. For the duty ratio of 40 to 60%, the mass flow rate through the valve was observed to depend on the pressure difference across the valve as well as the duty ratio, while it solely depended on the pressure difference fur the duty ratio above 60%.

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A Study on the Typology and the Characteristics of the Architectural Zenithal Opening -Focused on the Inflow Methods of the Zenithal Light- (천창의 유형및 특성에 관한 연구 -빛의 유입 방법을 중심으로-)

  • Ryu, Joohi;Kim, Young-Suk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.8
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    • pp.5619-5626
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    • 2015
  • The zenithal light is the one that is entered down into the interior space or the spaces such as the inner court, through windows high located in the wall or openings of the roof. The aim of this study is to analyze the types of mechanism for the zenithal light by studying some examples related to the zenithal opening, and to investigate those characteristics. One of the most important features is a structural unit of the skylight entering the room. In this study, according to the structural unit, the direct light type, the duct-type and the shade type was distinguished, and each type can be divided into several modified types. Precisely, the direct light type is divided into an unexposed type and an exposed type of the source of light. The duct type is also divided into an intensive duct type and a distributed duct type. The shade type is classified into a ceiling surface shade, a reflections objet shade, a double ceiling shade and a wall shade.

Comparison of Loss Coefficient using 1-inch Ball and Glove Valve Opening Ratio (1인치 볼 밸브 및 글로브 밸브에 대한 개도율에 따른 손실계수(k) 비교에 관한 연구)

  • Kang, Chang-Won;Yi, Chung-Seob;Lee, Chi-Woo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.9
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    • pp.63-69
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    • 2021
  • This study aims to determine the flow characteristics of a one-inch small ball valve and glove valve used in industrial plants. The flow was changed through an experimental equipment, and the internal flow characteristics of the valves were compared. Considering the pressure drop, the decrease in the slope of the ball valve based on the degree of the valve opening was relatively greater than that of the glove valve; further, the slope of the glove valve was gentle while the pressure drop was high. The flow velocity of the ball valve remains consistent after the valve was opened by 70%, whereas the flow velocity of the glove valve constantly increased. The valve loss factor of the ball valve was relatively low compared with that of the glove valve. When the valve was opened by 20%, which is the beginning stage of the valve opening, the valve loss factor of the ball valve was high and gradually became low. This is a structural problem of the ball valve, and the loss factor is significant because the flow path installed at the ball valve has a considerably small area. However, the overall loss factor of glove valve is high because it has a complicated structure of flow path.

Steady-Flow Characteristics and Its Influence on Spray for Direct Injection Diesel Engine

  • Jeon, Chung-hwan;Park, Seung-hwan;Chang, Young-june
    • Journal of Mechanical Science and Technology
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    • v.16 no.7
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    • pp.986-998
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    • 2002
  • Flow and spray characteristics are critical factors that affect the performance and exhaust emissions of a direct injection diesel engine. It is well known that the swirl control system is one of the useful ways to improve the fuel consumption and emission reduction rate in a diesel engine. However, until now there have only been a few studies on the effect of flow on spray. Because of this, the relationship between the flow pattern in the cylinder and its influence on the behavior of the spray is in need of investigation. First, in-cylinder flow distributions for 4-valve cylinder head of DI (Direct Injection) Diesel engine were investigated under steady-state conditions for different SCV (Swirl Control Valve) opening angles using a steady flow rig and 2-D LDV (Laser Doppler Velocimetry). It was found that swirl flow was more dominant than that of tumble in the experimented engine. In addition, the in-cylinder flow was quantified in terms of swirl/tumble ratio and mean flow coefficient. As the SCV opening angle was increased, high swirl ratios more than 3.0 were obtained in the case of SCV -70° and 90°. Second, spray characteristics of the intermittent injection were investigated by a PDA (Phase Doppler Anemometer) system. A Time Dividing Method (TDM) was used to analyze the microscopic spray characteristics. It was found that the atomization characteristics such as velocity and SMD (Sauter Mean Diameter) of the spray were affected by the in-cylinder swirl ratio. As a result, it was concluded that the swirl ratio improves atomization characteristics uniformly.

A Parameter Study on the Frequency Characteristics of the Structural-acoustic Coupled System (구조-음향 연성계의 경계값 변화에 따른 방사음 변화)

  • 김양한;서희선
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.7
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    • pp.604-611
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    • 2004
  • It is well known that wall impedance essentially determines how sound wave transmits from one place to another. The wall impedance is related with its dynamic properties : for example, the mass, stiffness, and damping characteristics. It is noteworthy, however, that the wall impedance is also function of spatial characteristics of two spaces that is separated by the wall. This is often referred that the wall is not locally reacting. In this paper, we have attempted to see how the acoustic characteristics of the two spaces is affected by various structure parameters such as density, applied tension, and a normalized length of the wall. Calculations are conducted for two different modally reacting boundary conditions by modal expansion method. The variation of the Helmholtz mode and the structural-dominated mode are analyzed as the structure parameters vary. The displacement distribution of the structure, pressure and active intensity of the inside and outside cavity are presented at the Helmholtz mode and the structure-dominated mode. It is shown that the frequency characteristics are governed by both structure-and fluid-dominated mode. The results exhibit that the density of the structure is the most sensitive design parameter on the frequency characteristics for the coupling system as we could imagine in the beginning. The Helmholtz mode frequency decrease as density increases. However. it increases as applied tension and an opening size increase. The bandwidth of the Helmholtz mode is mainly affected by density of the structure and its opening size.