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A Study on Machinability of SM55C for Deep Hole Drilling (Deep Hole 가공시 SM55C의 절삭성에 관한 연구)

  • 장성규
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.7 no.4
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    • pp.56-63
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    • 1998
  • The purpose of this is to analyze experimentally how the change of cutting speed have effects on hole over size of cutting hole, surface roughness of workpiece and roundness during the deep hole machining of SM55C with solid BTA drill using BTA drilling system. Conclusion reached is as follows. (1) The diameter was expanded for 25$\mu$m at the first section and then was reduced 0$\mu$m and 15$\mu$m respectively at the 10m and 20m section comparing to the diameter of tool with respect to the variation of cutting length at 70m/min of cutting speed. 0.15mm/rev of feed. (2) It was proved that roughness was below 8.67$\mu$m for the whole section of cutting length. (3) The roundness has been below 12$\mu$m. Regarding the polygon phenomenon, it has been proved that not only uneven best at 70m/min of cutting speed. 0.15mm/rev of feed.

Bending Characteristic Evaluations Circular Cross-section Carbon Composite and Hybrid Structural Material (원통단면 탄소복합재와 혼성 구조부재의 굽힘 특성 평가)

  • Kim, Jung-Ho;Jeong, Jong-An;Kim, Ji-Hoon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.3
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    • pp.421-424
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    • 2012
  • Carbon Fiber reinforced composite material can be designed for the optimized performances of structural member that have achieve appropriate mechanical properties with cross-sectional shape, fiber direction, stacking sequence and thickness. So there are needed extensive databases each optimal design of CFRP structural member by impact through the preparation of different shape, interface number, thickness and stacking angle. When pressure is applied to structural member, compression, bending and torsion is shown on the corresponding member. For the effective utilization of fiber reinforced composite material as main structural member, optimized design technology should be established to maximize mechanical properties for compression, bending and torsion. In this paper, CFRP prepreg sheet with different stacking angle is manufactured in CFRP and hybrid(Al+CFRP) with circular cross-section. Strength and stiffness is gotten respectively by flexure test. CFRP structure and hybrid structure can be compared with each other. The best design guideline can be analyzed by use of this study result.

Variation in Resistance of Poplar Clones to Melampsora Leaf Rust (Melampsora 잎녹병에 대한 포플러 클론의 저항성 변이)

  • Woo, Kwan-Soo
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.13 no.4
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    • pp.171-175
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    • 2011
  • This study was conducted to determine the susceptibility of 15 clones of native and foreign poplar species and their hybrids to Melampsora leaf rust and to select resistant clones at a nursery stool bed. Rust severities of individual trees were determined by estimating the percentage of infected leaves on the trees in addition to comparing the infected leaves with the infection diagrams. Three hybrids out of 15 clones were selected as resistant clones to the Melampsora leaf rust in Korea. Bong-wha 1 and Hyunsasi 3 belong to section Leuce, and Dorskamp belongs to section Aigeiros. Based on our results, we recommend Dorskamp as the best resistant clone to poplar leaf rust.

Gestational Diabetes in a Yorkshire Terrier Dog (요크셔테리어종 개에서 발생한 임신성 당뇨병)

  • Yoon, Won-Kyoung;Suh, Sang-Il;Hyun, Changbaig
    • Journal of Veterinary Clinics
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    • v.32 no.2
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    • pp.180-182
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    • 2015
  • A 3 year-old pregnant female Yorkshire terrier dog was presented with major complaints of polyuria and polydipsia. Laboratory tests found persistent hyperglycemia and glucosuria. Abdominal ultrasound study found 2 dead fetuses. Ovarian hysterectomy was performed to remove the dead fetuses. After ovarian hysterectomy, the level of blood glucose was returned to normal range. In addition, the clinical signs and urine glucose were all disappeared. Based on findings on laboratory tests and follow-up study, the case was diagnosed as gestational diabetes mellitus. To our best knowledge, this is the first case report describing a gestational diabetes mellitus of dog in Korea.

Impacts of the Digital Economy on Manufacturing in Emerging Asia

  • Kim, Jaewon;Abe, Masato;Valente, Fiona
    • Asian Journal of Innovation and Policy
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    • v.8 no.1
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    • pp.1-30
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    • 2019
  • The advent of digitalisation has transformed economies into more integrated, but increasingly complex systems. This new trend has brought dynamic changes in the manufacturing sector through advanced ICT infrastructure, smart factories, digitally-controlled logistics, and skilled ICT-labour. The impacts of the digital economy on manufacturing could be best illustrated through "Industry 4.0." With this wave of technological advancement, countries aim to establish an industrial ecosystem where every manufacturing process and function is connected and interacts through digital networks. Industry 4.0 presents opportunities for Emerging Asia, as the region has emerged as a fast-growing manufacturing hub and particularly a production base for ICT goods. However, growing production capacity, increased exports, and increases in FDI in the field of ICT goods manufacturing have so far contributed little to the development and diffusion of ICT. A huge gap exists in the ICT uptake amongst countries and between small and large firms. This paper highlights the level of Industry 4.0 readiness of Emerging Asia and key factors that determine its enhancement.

Effectiveness of Active Warming Intervention for Women Undergoing Cesarean Section: A Systematic Review and Meta-analysis (제왕절개 환자에서 적극적 가온 요법의 효과: 체계적 문헌고찰 및 메타분석)

  • Choi, Jung Eun;Kim, Mee Sun;Song, Jin Ran
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.24 no.3
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    • pp.167-180
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    • 2017
  • Purpose: The aim of this study was to synthesize the best available evidence for active warming interventions during cesarean section. Methods: A database search was done for randomized controlled trials utilizing active warming interventions. Maternal temperature, shivering and neonatal temperature were evaluated as outcome variables. Data were analyzed using Cochrane Review Manager software Version 5.3. Results: Thirteen studies including 1306 patients were reviewed. The degree of lowering of maternal temperature decreased in the warmed fluids (MD 0.51; p=.004) and warming mattress interventions (MD 0.22; p<.001) compared with control groups. Incidence of shivering was also lower in the active warming group (OR 0.55; p=.003). There was no statistically significant difference in maternal temperature with a forced air warming intervention (MD 0.64; p=.15) or in neonatal temperature (MD 0.12; p=.26). Conclusion: Findings show that with warmed fluids and warming mattresses applied during cesarean sections maternal temperature decline was reduced and also the incidence of shivering declined, but no significant effect was observed for forced air warming interventions. These findings provide a basis for developing a warming guideline for women having a cesarean section and will help to improve the quality of care for cesarean section patients.

Influence of implant misplacement on the success of the final prosthesis: Subjective evaluation by a prosthodontist of dental implants placed by an oral and maxillofacial surgeon (임프란트 식립오류가 최종 보철물의 성공에 미치는 영향: 구강악안면외과의사에 의해 식립된 치과임프란트에 대한 보철의사의 주관적 평가)

  • Kim, Young-Kyun;Hwang, Jung-Won;Lee, Hyo-Jung;Yeo, In-Sung;Yun, Pil-Young
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.35 no.6
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    • pp.437-441
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    • 2009
  • Purpose: In many cases, the erroneous placement of a dental implant brings about undesirable results. Here, the effect of dental implant placement on the success of the final prosthesis was evaluated from the point of view of the prosthodontist. Materials and Methods: All surgical operations were performed by the same oral surgeon with the same surgical protocol and all prosthodontic procedures were performed by the same prosthodontist. The problems faced by the prosthodontist, their causes, and their effect on prosthesis success were identified. The success of the final prostheses was evaluated by the same prosthodontist. Results: Only 53% (238 implants in 105 patients) of dental implants were not associated with prosthodontic problems. Multiple implant placement (more than three implants) was associated more frequently with prosthodontic problems. Conclusions: The data indicate that the satisfactory construction of a prosthesis is highly dependent on the placement of the dental implant in the best possible position. It is strongly recommended that the oral surgeon and the prosthodontist engage in pre-operative discussions to establish a top-down treatment plan, as this will improve implant placement and ultimately the success of the prosthesis.

The Architecture of Tool server in MPEG-21

  • Kim, Kwang-Yong;Hong, Jin-Woo;Kim, Jin-Woong
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.272-275
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    • 2003
  • This paper presents the role and its function of Tool server. MPEG-21 means multimedia framework for delivery and consumption of multimedia which is being discussed in ISO/IEC 21000. A view of MPEC-21 aims to define multimedia framework to enable transparent use of multimedia resource across a wide range of networks and devices used by different communities. MPEG-21 will enable all-electronic creation delivery and trade of digital multimedia content and transparent usage of various content types on network device. Therefore, we can provide access to information and services from almost anywhere at anytime with various terminals and networks. In order to support multimedia delivery chain that contains content creation, production, delivery and consumption, we need many standards(elements) for identify, describe, manage and protect the content. Thus, we define Digital Item Player(DIP), Digital Item Adaptation(DIA) server and Tool server as primary objects of MPEG-21 multimedia framework. DIP provides a function which creates and consumes Digital Item(DI) as a kind of a digital object by user. A DI contains both media resources and metadata including rights information. DIA server deals with the usage environment description schema of the user characteristics, terminal and network characteristics and natural environments. DIA server adapts the original DI to the usage environment description sent from the terminal and transmits the adapted DI to the terminal. Tool server searches for a tool requested from DIP or DIA and downloads the best tool to DIP or DIA server. In this paper, we present how Tool sewer is organized and is used among 2 primary objects. The paper is structured as followings: Section 1 briefly describes why MPEG-21 is needed and what MPEG-21 wants. We see requirement that tool server must equip functionally in section 2. The proposed tool server,its structure and its functionality are presented in section 3. Section 4 explains a scenario that tool server transmits tool to DIP and shows the experimental result. The paper concludes in section 5.

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Mapping the water table at the Cheongju-Gadeok site of the Korea National Groundwater Monitoring Network using multiple geophysical methods

  • Ju, Hyeon-Tae;Sa, Jin-Hyeon;Kim, Ji-Soo
    • The Journal of Engineering Geology
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    • v.27 no.3
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    • pp.305-312
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    • 2017
  • The most effective way to distinguish subsurface interfaces that produce various geophysical responses is through the integration of multiple geophysical methods, with each method detecting both a complementary and unique set of distinct physical properties relating to the subsurface. In this study, shallow seismic reflection (SSR) and ground penetrating radar (GPR) surveys were conducted at the Cheongju-Gadeok site of the Korea National Groundwater Monitoring Network to map the water table, which was measured at 12 m depth during the geophysical surveys. The water table proved to be a good target reflector in both datasets, as the abrupt transition from the overlying unsaturated weathered rock to the underlying saturated weathered rock yielded large acoustic impedance and dielectric constant contrasts. The two datasets were depth converted and integrated into a single section, with the SSR and GPR surveys conducted to ensure subsurface imaging at approximately the same wavelength. The GPR data provided detailed information on the upper ~15 m of the section, whereas the SSR data imaged structures at depths of 10-45 m. The integrated section thus captured the full depth coverage of the sandy clay, water table, weathered rock, soft rock, and hard rock structures, which correlated well with local drillcore and water table observations. Incorporation of these two geophysical datasets yielded a synthetic section that resembled a simplified aquifer model, with the best-fitting seismic velocity, dielectric constant, and porosity of the saturated weathered layer being $v_{seismic}=1000m/s$, ${\varepsilon}_r=16$, and ${\phi}=0.32$, respectively.

Study on the Determination of Fire Protection Thickness based on Section Factor (강재의 단면형상에 따른 내화피복두께 산정 연구)

  • 정청운;지남용;권인규
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.05a
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    • pp.139-142
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    • 2003
  • Traditionally, the thickness of fire protection materials of structural elements such as beam and column have been decided by fire test using the predominant steel section of $H-300{\times}300{\times}10{\times}15$ for column and $H-400{\times}200{\times}8{\times}13$ for beam in Korea. But this way of determination of fire protection thickness yields very unduly results. Because the temperature-increment rate of structural steel elements depends mainly on magnitude of their cross-areas. In general, the thicker size of cross-areas for structural elements, the lower temperature shows up. It had already proved that the fire protection thickness only depends on the size of cross-areas and the fire protection method for three-fide or four-side exposed conditions in European countries, the United State of America and so on. To demonstrate there would be differences among various cross-areas for structural elements, we conducted several fire tests with full-scale specimens of beams and columns. For the determination of critical temperature for steel section when the fire resistant performance is needed to be decided, we conducted with a loaded fire test for beam and column, respectively. The small column in 1.0 meter length and beam in 1.5 meter length were used in order to deprive the rational fire protection thickness of structural elements such as beam and column, respectively. After test, we could obtain there were significant temperature lass between higher cross-areas and lower cross-areas. The critical temperature of steel as a criterion is used 538$^{\circ}C$ for column and 593$^{\circ}C$ for beam which is from ASTM E 119 because we don't make provisions as critical temperature by elements. We could consider that the best way of determination of fire protection thickness is using the following multi-regression equation which was deprived from several fire tests using the concept of section factor, FR(column) = 0.17 +5191.49t A/Hp + 40.77t, FR(beam) = 0.25 +6899.31t A/Hp + 32.60t(where, FR means fire resistant time, t means thickness, A means cross-area and Hp means heated parameter).

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