• Animal cells and systems
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• 제2권4호
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• pp.477-481
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• 1998

Previous studies have postulated that isometric animals exert similar locomotory capacity (speed, distance) because the amount of energy available for the motion would be the same regardless of body mass (m). To test propriety of this theory, we examined body shape and take-off potential of two frog species, Rana nigromaculata (powerful jumpers) and Bombina orientalis (slow hoppers). Morphological measurements included thigh muscle mass (indicative of total muscle force), hindlimb length (L, determining acceleration distance), and interilial width (shaping take-off motion). To gauge locomotory capacity, take-off speed (v) and take-off angle ($\theta$) were measured from video analyses, and jump distance (R) and take-off Power ($P_{t}$ ) were calculated from equations $R=V^{2}sin2\theta/g$ and ($P_{t}$＝$㎷^{3}/2L$(where g is the gravitational constant). Scaling exponents of morphometric variables for both species were 0.96-1.11 for thigh muscle mass, 0.28-0.29 for hindlimb length, and 0.30-0.36 for interilial width. Scaling exponents of locomotory performance for the two species were -0.01-0.14 for take-off speed, 0.24-0.31 for jump distance, and 0.66-0.84 for take-off power. The results demonstrate that the frogs of this study showed isometric body shape within species, but that take-off response changed allometrically with body mass, indicating that these data did not fully support the previous proposition. An exception was found in take-off speed of B. orientalis, in which the speed changed little with body mass (slope＝-0.01). These findings suggest that the energy availability approach did not properly explain the apparent allometric relations of the take-off response in these animals and that an alternative model such as a power production approach may be worth addressing.

• 한국구조물진단유지관리공학회 논문집
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• 제22권1호
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• pp.90-98
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• 2018

최근 철근 콘크리트 구조물에 다양한 철근 이음이 사용되고 있다. 이에 따라 커플러 이음 철근의 인장 특성에 대한 파악이 중요해졌다. 본 연구에서는 커플러 이음 철근의 연성도에 대한 평가를 위하여 ASTM A615 기준에 따라 생산된 Grade 60 D22(#7), D29(#9), 그리고 두 종류의 커플러를 상대로 1축 인장시험을 수행하였다. 보다 정확하고 다양한 지점에서 자유로운 계측이 가능한 이미지 프로세싱 방법을 사용하여 변형률을 계측하였다. 1축 인장시험 결과, 응력-변형률 관계와 응력 단계별 종방향 변형률 분포를 산출할 수 있었고, 이를 통하여 동일한 표점거리 내에서 커플러 이음 부분이 많이 차지할수록 평균변형률이 낮아지는 것을 알 수 있었다. 또한 커플러 이음철근의 극한거동 및 파단 시변형률에 대한 평가를 통해 커플러의 길이에 대한 한계상태변형률과 파단변형률과의 상관관계를 정식화하였다.

• The Journal of Advanced Prosthodontics
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• 제8권1호
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• pp.62-69
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• 2016

PURPOSE. The purpose of this study was to evaluate the effects of abutment screw length and cyclic loading on the removal torque (RTV) in external hex (EH) and internal hex (IH) implants. MATERIALS AND METHODS. Forty screw-retained single crowns were connected to external and internal hex implants. The prepared titanium abutment screws were classified into 8 groups based on the number of threads (n = 5 per group): EH 12.5, 6.5, 3.5, 2.5 and IH 6.5, 5, 3.5, 2.5 threads. The abutment screws were tightened with 20 Ncm torque twice with 10-minute intervals. After 5 minutes, the initial RTVs of the abutment screws were measured with a digital torque gauge (MGT12). A customized jig was constructed to apply a load along the implant long axis at the central fossa of the maxillary first molar. The post-loading RTVs were measured after 16,000 cycles of mechanical loading with 50 N at a 1-Hz frequency. Statistical analysis included one-way analysis of variance and paired t-tests. RESULTS. The post-loading RTVs were significantly lower than the initial RTVs in the EH 2.5 thread and IH 2.5 thread groups (P<.05). The initial RTVs exhibited no significant differences among the 8 groups, whereas the post-loading RTVs of the EH 6.5 and EH 3.5 thread groups were higher than those of the IH 3.5 thread group (P<.05). CONCLUSION. Within the limitations of this study, the external hex implants with short screw lengths were more advantageous than internal hex implants with short screw lengths in torque maintenance after cyclic loading.

• 한국의상디자인학회지
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• 제12권2호
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• pp.131-138
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• 2010

The purposes of this study are for current manufacturing status of the formal knit slacks for the middle aged women. As for the methodology, five manufacturers specializing in formal knitwear brands were subjected to the study, to examine the current manufacturing status of the knit slacks for the middle aged women, by conducting interviews and questionnaire with patterner and designer. The questionnaire items are 20 ones including general questions on manufacturing of the knit slacks, questions on materials used in manufacturing, and on sewing. The results are as followings : First, as for the manufacturing structure of the knit slacks manufacturer, all manufacturers directly manufactured knit slacks in their own factory, and the manufacturing was comprised of 10% in woven slacks and 90% in knit slacks. Second, as for the type of yarn mostly used in fabric knitting for the knit slacks, wool was used mostly for F/W, and acrylic or Saint yarn for S/S. As for the types of knit, Milano rib stitch and Half Milano rib stitch were used for wool and acrylic knitting, and plain stitch was used for Saint yarn. As for the gauge, 12G and 14G were used, whereas 7G, 12G was used for Saint yarn. Repair requests of the knit slacks were mostly on the length of the pants, such as shortening hip circumference and crotch length, or widening waist and hip area. The study shows that the size of knit slacks did not fit the body type of customers.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.149-152
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• 2008

광섬유센서 계측시스템의 대표적인 방식인 광섬유격자센서(FBG센서)는 포인트 센서 개념의 센서로써 측정하고자 하는 지점에 설치되는 반영구적이며, 분해능이 우수한 센서이다. 광섬유센서는 유리섬유의 코어(Core)/클래딩(Cladding)부분과 유리섬유를 보호하기 위한 코팅(Coating)으로 구분된다. 이와 같이 구성된 광섬유에 외력이 작용할 경우 유리섬유부분과 코팅부분 사이에서 미끄러짐(Slip)현상이 쉽게 발생하는 단점이 있어 패키징을 한 후 데이터에 오류가 생기는 경우가 있었다. 두 재료 간에 발생하는 미끄러짐(Slip)현상을 방지하기 위해서 광섬유의 코팅을 부분적으로 박피한 후 유리섬유부분을 직접 특정한 고정구로 고정하는 방식을 적용하고 프리스트레인을 부가하여 외력에 의한 변형을 정밀하게 측정할 수 있게 하였다. 콘크리트의 변형률을 측정하기 위하여 1미터의 게이지길이를 갖는 광섬유격자센서를 고정하고 프리스트레인을 부가함으로서 광섬유센서의 장점을 더욱 높여 콘크리트구조물의 인장 및 압축 거동을 정밀하고도 장기간 지속적으로 측정할 수 있게 하였으며, 이를 이용하여 인근의 전력구 공사 기간 동안 지하철 콘크리트 라이닝구조물의 안전을 감시하였다.

• 펄프종이기술
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• 제47권5호
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• pp.80-84
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• 2015

Softness is considered one of the most important attributes of hygiene paper such as tissue and towel. Being subjective in nature, however, softness attribute has been generally believed to be impossible to evaluate using objective methods. Hallmark in his pioneering work proposed that tissue subjective softness should be mainly consisted of the bulk softness component and surface softness component. The bulk softness component can be determined by tensile stiffness; the surface softness component by surface tester. The surface friction turns out far more important than the surface roughness in determining the surface softness component. It cannot be too much emphasized that both results of the tensile stiffness and the surface friction should depend on measuring conditions such as an instrument used, sample sizes (e.g., basis weight, length, and width) and operating conditions of the instrument (e.g., gauge length, cross-head speed, size of stylus, and its scanning speed). This indicates that a direct comparison of the test results would be impossible or misleading unless they have been tested under the identical conditions. This may explain why the standard objective test method for tissue softness has not been available at present.

• 한국전산구조공학회논문집
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• 제21권6호
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• pp.607-613
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• 2008

광섬유의 클래딩 부분을 별도의 고정구에 직접 부착하는 방식으로 고정하여, 변형발생 시 광케이블을 구성하는 재료들 사이에서 발생하는 미끄러짐(Slip)현상을 방지하고, 외력에 의해 발생하는 변형을 정확하게 측정이 가능하도록 함과 기존 광섬유격자센서가 자체적으로 압축변형의 측정이 곤란한 점을 개선하기 위해 미리 긴장(Pre-Strain)상태를 유지하기 위하여 두 개의 접점사이를 볼트와 너트로 조절하여 프리스트레인 가변이 가능하도록 하여 인장/압축변형 측정을 가능하게 한 광섬유격자센서 패키지를 사용하는 지하구조물 변위 모니터링시스템이 본 연구에 의해 개발되었다. 이러한 광섬유격자센서 패키지는 콘크리트 라이닝구조물에 콘크리트의 불균일성을 극복하고 대표성을 가지기 위해 1미터 게이지 길이를 갖도록 하여 모니터링시스템에 적용되었으며, 대구 지하철 지하구조물에 현재 운영 중인 이 시스템은 한국전력 공동구 설치공사가 진행되면서 구조물에 미치는 영향을 판단하기 위한 모니터링시스템으로 적용되었다.

• 대한가정학회지
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• 제35권4호
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• pp.79-94
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• 1997

This study was performed to develop a basic stacks pattern for middle-aged women reflecting the characteristics of their lower body types. Anthropometric measurements using sliding guage method were carried out for 4 women 40's For the analysis of the lower body types horizontal and vertical section maps obtained by sliding gauge method and 2 indices were produced. Based on the slacks construction components produced by the drafts of their lower body surface experimental slacks pattern was designed. Multiple comparison test was used to compare 3 existing slacks patterns with the experimental pattern. 1. The results of the body section map analysis were as follows: 1) In the frontal view silhouette of vertical section maps there were less individual differences in items with skeleton landmarks than those without them. 2) In the shape of horizontal section maps waist section represented more round shape than the others and thigh maximum width section had the flattest shape. Flat ratios(depth/width) of subjects were much higer than those of young women which clarified the change of depth was bigger than that of width with aging process. 2. The slacks construction components for pattern drafting were as follows: 1)Ease amount of waist was 0.5cm and front and back waist girth difference was 1.2cm Ease amount of hip was 1,8cm and front and back hip girth difference was 0.7 cm 2) The amount of dart intake incresed in the order of side(4cm) back(3,6cm) from (2.8cm) The length of dart leg incresed in the order of front side back.

• 한국생산제조학회지
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• 제6권4호
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• pp.80-88
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• 1997

An experimental investigation of the fatigue through crack growth behavior under simple stepped variable loading condition has been performed using Al7075-T651. Experiments were carried out by using cantilever bending type specimens, with chevron notches on a small electro-magnetic test machine. Tensile overloads have a retarding effect on the fatigue crack growth rates, therefore tensile overloads were used for the beneficial effect on the fatigue life. While in most cases compressive overloads have only a vanishing effect on crack growth rates, some experiments with single edge crack tension specimens reveal a marked growth retardation. The stress ratios used in this investigations varies from R=0.32 to 0.81, from R=0.04 to 0.76, from R=-0.15 to 0.73, and from R=-0.33 to 0.68 and the peak load for each case was not varied. The crack growth and crack closure were measured by Kikukawa's compliance method with a strain gauge mounted on the backside of each specimens. The results obtained are as follows. When the stepped variable load was applied, the smaller the stress ration was, the larger the delayed retardation of the crack growth rate was. The fatigue crack growh rate data obtained for through cracks were plotted well against the effective stress intensity factor range from 4.0 to 20.0MP{a^{SQRT}m}. It was found that the effective stress intensity factor range ratio was related well to the opening stress intensity factor, the maximum stress intensity factor, and crack length.

• 대한기계학회논문집A
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• 제24권6호
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• pp.1540-1546
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• 2000

Recently, force measurement systems are commonly used in many industrial fields and the precision of the measurement system is getting more important as the industry needs more precise tools and in struments to make high quality products. However, a high precision force measurement system is hard to make unless we know precisely the causes, quality and quantity of measurement errors in advance. In this work, many possible mechanical causes of measurement errors are reviewed including ratio of length to diameter of sensing part, radius of contact area, radius of bearing part, ratio of material properties and change of boundary conditions. Also, the measurement errors are analyzed by nonlinear finite element method and the nonlinear behavior of the errors are investigated. The results can be used to design force measurement systems and expected to be very useful especially for compact type load cells.