• Title/Summary/Keyword: gap joint

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A comparative study of gold UCLA-type and CAD/CAM titanium implant abutments

  • Park, Ji-Man;Lee, Jai-Bong;Heo, Seong-Joo;Park, Eun-Jin
    • The Journal of Advanced Prosthodontics
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    • v.6 no.1
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    • pp.46-52
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    • 2014
  • PURPOSE. The aim of this study was to evaluate the interface accuracy of computer-assisted designed and manufactured (CAD/CAM) titanium abutments and implant fixture compared to gold-cast UCLA abutments. MATERIALS AND METHODS. An external connection implant system (Mark III, n=10) and an internal connection implant system (Replace Select, n=10) were used, 5 of each group were connected to milled titanium abutment and the rest were connected to the gold-cast UCLA abutments. The implant fixture and abutment were tightened to torque of 35 Ncm using a digital torque gauge, and initial detorque values were measured 10 minutes after tightening. To mimic the mastication, a cyclic loading was applied at 14 Hz for one million cycles, with the stress amplitude range being within 0 N to 100 N. After the cyclic loading, detorque values were measured again. The fixture-abutment gaps were measured under a microscope and recorded with an accuracy of ${\pm}0.1{\mu}m$ at 50 points. RESULTS. Initial detorque values of milled abutment were significantly higher than those of cast abutment (P<.05). Detorque values after one million dynamic cyclic loadings were not significantly different (P>.05). After cyclic loading, detorque values of cast abutment increased, but those of milled abutment decreased (P<.05). There was no significant difference of gap dimension between the milled abutment group and the cast abutment group after cyclic loading. CONCLUSION. In conclusion, CAD/CAM milled titanium abutment can be fabricated with sufficient accuracy to permit screw joint stability between abutment and fixture comparable to that of the traditional gold cast UCLA abutment.

A study of pants pattern for bowlegged females in their twenties (O자형 다리 20대 여성의 팬츠 패턴 연구)

  • Seo, Yoo Ra;Kim, Hyo Sook
    • Journal of the Korea Fashion and Costume Design Association
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    • v.23 no.2
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    • pp.79-91
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    • 2021
  • This study aims to rectify the disfigurement of bowlegged, (which means they have a gap between knees due to knee joint problems) females in their twenties through the development of pants patterns. The contents of the study are as follows: First, two types of basic pattern-making methods were selected. Two mock-ups, which were made by using these pre-selected basic patterns, were worn by three bowlegged participants and evaluated with a fit test. A basic pattern, which had good body fit was selected, which had a bubble or a wedge at in crotch area and roomy or snug upper thigh. Second, the mock-up, which was made by using the selected basic pattern, led to the outward movement of crease lines. Two types of patterns that were adjusted were evaluated through a fit test. As a result, an effective adjustment for moving the crease line to the outside or to the center was to cut along the slash line of a horizontal balance line to, but not through the crotch seam to spread the pattern at the hip. Third, three patterns were readjusted using the chosen alteration pattern, and the crotch seam and spread patterns of 1 cm, 2 cm, and 3 cm at the hip were applied. As a result of the evaluation of the fit test, three participants-the majority-showed a better fit when the spread amount in the pattern was 2 cm, although every participant did have a different gap between the knees. This study has significance in which rectifies the disfigurement of bowlegged individuals through the development of patterns for females in their twenties who are bowlegged.

Necessity and Expected Effects of Introducing the Korean Version of Tax Lease Scheme for Ships (한국형 선박 조세리스제도 도입 필요성과 기대효과)

  • Sung-Hwa Park;Hanna Kim
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2022.06a
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    • pp.369-370
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    • 2022
  • In Korea's ship finance, due to the nature of pro-cyclical investment, the private sector's ship finance greatly shrinks during the shipping recession, and policy financial institutions take the lead in ship finance. Meanwhile, the government established the 「Strategy for the Realization of Shipping Industry Leader」 (June 29, '2) and set a development goal by 2030 through support such as securing new high-efficiency ships. To promote financial investment. However, investment in the shipping industry is not easy to induce due to risks and uncertain market conditions. Therefore, it is necessary to review tax benefits that can induce joint investment of investors at the government level. Therefore, it is necessary to introduce a Korean version of tax lease scheme for ships in order to resolve the liquidity gap in the domestic ship finance market and successfully implement the five-year plan for reconstruction of shipping industry.

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A design approach of integral-abutment steel girder bridges for maintenance

  • Kim, WooSeok;Jeong, Yoseok;Lee, Jaeha
    • Steel and Composite Structures
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    • v.26 no.2
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    • pp.227-239
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    • 2018
  • Integral abutment bridges (IABs) have no joint across the length of bridge and are therefore also known as jointless bridges. IABs have many advantages, such as structural integrity, efficiency, and stability. More importantly, IABs have proven to be have both low maintenance and construction costs. However, due to the restraints at both ends of the girder due to the absence of a gap (joint), special design considerations are required. For example, while replacing the deck slabs to extend the service life of the IAB, the buckling strength of the steel girder without a deck slab could be much smaller than the case with deck slab in place. With no deck slab, the addition of thermal expansion in the steel girders generates passive earth pressure from the abutment and if the applied axial force is greater than the buckling strength of the steel girders, buckling failure can occur. In this study, numerical simulations were performed to estimate the buckling strength of typical steel girders in IABs. The effects of girder length, the width of flange and thickness of flange, imperfection due to fabrication and construction errors on the buckling strengths of multiple and single girders in IABs are studied. The effect of girder spacing, span length ratio (for a three span girder) and self-weight effects on the buckling strength are also studied. For estimation of the reaction force of the abutment generated by the passive earth pressure of the soil, BA 42/96 (2003), PennDOT DM4 (2015) and the LTI proposed equations (2009) were used and the results obtained are compared with the buckling strength of the steel girders. Using the selected design equations and the results obtained from the numerical analysis, equations for preventing the buckling failure of steel girders during deck replacement for maintenance are presented.

The sequential management of recurrent temporomandibular joint ankylosis in a growing child: a case report

  • Cho, Jung-Won;Park, Jung-Hyun;Kim, Jin-Woo;Kim, Sun-Jong
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.38
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    • pp.39.1-39.6
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    • 2016
  • Background: Temporomandibular joint (TMJ) ankylosis in children often leads to facial deformity, functional deficit, and negative influence of the psychosocial development, which worsens with growth. The treatment of TMJ ankylosis in the pediatric patient is much more challenging than in adults because of a high incidence of recurrence and unfavorable growth of the mandible. Case report: This is a case report describing sequential management of the left TMJ ankylosis resulted from trauma in early childhood. The multiple surgeries including a costochondral graft and gap arthroplasty using interpositional silicone block were performed, but re-ankylosis of the TMJ occurred after surgery. Alloplastic TMJ prosthesis was conducted to prevent another ankylosis, and signs or symptoms of re-ankylosis were not found. Additional reconstruction surgery was performed to compensate mandibular growth after confirming growth completion. During the first 3 years of long-term follow-up, satisfactory functional and esthetic results were observed. Conclusions: This is to review the sequential management for the recurrent TMJ ankylosis in a growing child. Even though proper healing was expected after reconstruction of the left TMJ with costal cartilage graft, additional surgical interventions, including interpositional arthroplasty, were performed due to re-ankylosis of the affected site. In this case, alloplastic prosthesis could be an option to prevent TMJ re-ankylosis for growing pediatric patients with TMJ ankylosis in the beginning.

Study on copper end-tab shape for maximum heat discharging performance (방열 성능 향상을 위한 구리 엔드 탭의 최적형상 연구)

  • Choi, Yeou-Myeong;Choi, Yoon-Hwan;Cho, Sang-Myung;Park, Jung-Hyun;Lee, Yeon-Won
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.1
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    • pp.1-7
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    • 2017
  • When implementing butt joint welding of two plates, it is useful to attach end-tabs made of a metal with high heat conductivity (e.g., copper) at the front and back sides of the welded plates to prevent the bead from rolling down and prevent defects that may occur at the tips of the weld zone. In this study, the fin shape, which is known to have good heat discharging characteristics by natural convection, has been applied to enhance the cooling performance of the end-tab. From both experiment and numerical analysis, it was confirmed that end-tabs with fin-shaped holes have better heat discharging performance than end-tabs without holes. Through thermal and fluid flow analysis, the cooling rates of end-tabs with different hole shapes were estimated in order to figure out characteristics of shape factor that are important for the heat discharging performance. As a result, we found that the structure including vertical fins with optimal fin gap was the best-performing shape.

The Effect of Cold Air Therapy in Release of Inflammation on Rheumatoid Arthritis (류머티스 관절염 환자에게 한랭치료가 염증완화에 미치는 효과)

  • Nam, Ki-San;Han, Kyoung-Ju;Lee, In-Hak;Moon, Sung-Ki
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.5 no.2
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    • pp.85-93
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    • 2007
  • Summary of background data: It is researched until now and the researches against the effect of position cold treatment the effect which pain threshold, change of skin temperature, researches the effective stiffness, the coldness in the patient it applied and relax an inflammation do the researches against were insufficient. Purpose: This project was to see how much it gives effect by using the cold air therapy an inflammation relief of rheumatoid arthritis patient. Methods: The medical subjects were 10 people from standard to diagnosis category of American College of Rheumatology(ACR) who had rheumatoid arthritis and to inspect informations about inflammation relief, have inspected ESR(erythrocyte sedimentation rate) and WBC(white blood cells). The experiment method was to let the patient bend the joint and lay down flat and treat with cold air from 10 cm away from joint line repeating 5 minutes treatment 1 minute rest and 3 minutes treatment. ESR and WBC cold air therapy reported with 5 days gap and each patient has been applied for 3 times. Result: The 5th day and 10th days ESR and WBC value shows when using cold air therapy, there was a reduction on rejected group but didn't last long, but 15th day it showed only on WBC it had its attention. Conclusions: So the cold air therapy shows it has positive effects on inflammation relief of rheumatoid arthritis patient.

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Study on the Relationship Between Emission Signals and Weld Defect for In-Process Monitoring in CO2 Laser Welding of Zn-Coated Steel (아연코팅 강판의 CO2 레이저용접시 인프로세스 모니터링을 위한 측정신호와 용접결함과의 관련성 연구)

  • Kim, Jong-Do;Lee, Chang-Je
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.10
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    • pp.1507-1512
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    • 2010
  • In this study, the plasma induced by $CO_2$ laser lap welding of 6t Zn coated steel used for ship building was measured using photodiodes and a microphone. Then, the welding phenomenon with gap clearance of lap joint was compared with RMS-treated signal. Thus, we found that intensity of the RMS-treated signal increased with Zn vaporization; further, the presence of defects results in rapid variations with the RMS value as a function of lap-joint parameters. Besides, the FFT value of the raw signal with variations of changing welding parameters was calculated, and then the calculated FFT frequency value was set as the bandwidth of digital filter for a more accurate in-process monitoring. The RMS values were acquired by filtering the raw signal. By matching the weld beads and the calculated RMS values, we confirmed that there is a strong relationship between the signals and the defects.

Segmental Hard Shell Design of Knee Protector for Children Using 3D Printing (3차원 프린팅을 이용한 어린이용 무릎보호대의 분절형 하드쉘 설계)

  • Lee, Hyojeong;Lee, Yejin
    • Journal of Fashion Business
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    • v.21 no.4
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    • pp.116-126
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    • 2017
  • This study applied a segmented hard shell design on knee protectors for children with the objective of increasing mobility. The prototype of the hard shell that does not correspond to movement of the body among components of the knee protector was developed. Surface modeling was conducted based on 3D knee data to enhance comfort through optimized fit on the knee joint where the hard shell would be worn. For this, previous studies on changes in skin near the knee joint during knee flexion were reviewed to establish basic segmental lines. The basic design included six segments, and the number of segments was used as the design variable by increasing or decreasing it to 0, 3, 6, 9, and 14 segments. A prototype was produced from 3D printing with TPU material, worn for wearing assessment. Results revealed fewer numbers of segments resulting in less fit with the body, while actual appearance was stable. Meanwhile, the number of proper segments improved better fit with the body during movement. The wearing assessment revealed the amount of gap reflects change in skin length depending on movement. Assessment results demonstrated basic segment design, S6 with 6 segments, had the best design and most optimized fit. Findings in this study can provide key data for designing knee protection products for children.

Heat Loss Audit and Assessment of the Greenhouses Using Infrared Thermal Image Analysis (적외선 열화상 분석을 통한 온실의 열손실 진단 및 평가)

  • Moon, Jong-Pil;Yun, Nam-Kyu;Lee, Sung-Hyoun;Kim, Hak-Joo;Lee, Su-Jang;Kim, Young-Hwa
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.2
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    • pp.67-73
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    • 2010
  • Unlike Urban building, horticultural facilities has a lot of heat loss through plastic or glass covering material which could be much influential to growing plant and consuming energy for heating greenhouse. In many cases, heat loss from a break of cover, a gap of joint sealing, the entrance to greenhouse and windows for ventilation are the main factors considered in calculating the heating load for horticultural facilities. however the normal observation through human eye and digital camera could not recognize where the heat loss occurred. but the infrared thermal image camera with detecting thermal difference could be very effective for noticing heat loss by analyzing infrared thermal image. In this study, greenhouse structure, covering material, internal and external provisions for Horticultural facilities were surveyed in different sites and Infrared thermal camera shooting and image analysis were performed for auditing heat loss from cultivation facilities The results from this study were that unexpected heat loss had been noticed in 7 representative cases of greenhouse such as side wall covered with single or double plastic, and the joint of horizontal thermal curtain, roof without horizontal thermal curtain, entrance to greenhouse, windows for ventilation. the most important factors for keeping heat energy were whether the horizontal thermal curtain with multifold thermal material was installed or not. The internal or external covering using multifold thermal curtain proved to be the most effective ways to keep heat energy from losing through heat transmission, heat radiation. from inside to outside the horticultural facilities.