• 대한조선학회논문집
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• 제54권2호
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• pp.151-160
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• 2017

Growing demand and rapid development of the synthetic fiber rope in mooring system have taken place since it has been used in deep water platform lately. Unlike a chain mooring, synthetic fiber rope composed of lightweight materials such as Polyester(polyethylene terephthalate), HMPE(high modulus polyethylene) and Aramid(aromatic polyamide). Non-linear stiffness and another failure mode are distinct characteristics of synthetic fiber rope when compared to mooring chain. When these ropes are exposed to environmental load for a long time, the length of rope will be increased permanently. This is called 'the creep phenomenon'. Due to the phenomenon, The initial characteristics of mooring systems would be changed because the length and stiffness of the rope have been changed as time goes on. The changed characteristics of fiber rope cause different mooring tension and vessel offset compared to the initial design condition. Commercial mooring analysis software that widely used in industries is unable to take into account this phenomenon automatically. Even though the American Petroleum Institute (API) or other classification rules present some standard or criteria with respect to length and stiffness of a mooring line, simulation guide considers the mechanical properties that is not mentioned in such rules. In this paper, the effect of creep phenomenon in the fiber rope mooring system under specific environment condition is investigated. Desiged mooring system for a Mobile Offshore Drilling Unit(MODU) with HMPE rope which has the highest creep is analyzed in a time domain in order to investigate the effects creep phenomenon to vessel offset and mooring tension. We have developed a new procedure to an analysis of mooring system reflecting the creep phenomenon and it is validated through a time domain simulation using non-linear mooring analysis software, OrcaFlex. The result shows that the creep phenomenon should be considered in analysis procedure because it affects the length and stiffness of synthetic fiber rope in case of high water temperature and permanent mooring system.

• 패션비즈니스
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• 제19권4호
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• pp.120-134
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• 2015

This study aimed to determine the physical properties of silk and nylon fabrics that are treated with persimmon juice in accordance with irradiation time of ultraviolet spectrum. Persimmon juice dyeing has the advantage of using the tannin component of the persimmon. Tannin plays an important role in inhibiting photodegradation of fibers or polymers. Among fibrous materials, silk and nylon are prone to deterioration by light. Hence, this study aimed to reduce these weaknesses of silk and nylon by applying persimmon juice treatment. We accordingly carried out investigation and experiments on ultraviolet irradiation, and physical characteristics of treated fabrics. The persimmon juice treatment process led to increased weight and thickness. In addition, the air permeability of silk fabric was increased, as compared to the control specimen; whereas, that of nylon fabric was decreased. Both drape stiffness and flex stiffness of silk and nylon tended to be high in textiles processed with persimmon juice treatment, as compared to the control textile. Peak load and elongation at peak load of untreated samples clearly decreased in both silk and nylon fabrics with the increase of ultraviolet irradiation time, while those of persimmon juice treated samples increased. Furthermore, ultraviolet blocking ratio measurement indicated that the fabric specimens treated with persimmon juice blocked U.V. spectrum better than the control specimen.

• 한국해양공학회지
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• 제32권6호
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• pp.466-473
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• 2018

This paper presents an estimation method for the static configuration of a steel lazy wave riser (SLWR) using the dynamic relaxation method applied to estimate the configuration of structures with strong geometric non-linearity. The lumped mass model is introduced to reflect the flexible structural characteristics of the riser. In the lumped mass model, the tensions, shear forces, buoyancy, self-weights, and seabed reaction forces at nodal points are considered in order to find the static configuration of the SLWR. The dynamic relaxation method using a viscous damping formulation is applied to the static configuration analysis. Fictitious masses are defined at nodal points using the sum of the largest direct stiffness values of nodal points to ensure the numerical stability. Various case studies were performed according to the bending stiffness and size of the buoyancy module using the dynamic relaxation method. OrcaFlex was employed to validate the accuracy of the developed numerical method.

• 한국의류학회지
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• 제19권6호
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• pp.955-967
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• 1995

This study was performed to investigate the physical and chemical properties of the 5 kinds of fabrics dyed with persimmon juice and undyed fabrics. The difference between dyed and undyed fabrics was checked experimentally. Obtained results are as follows. 1. Bending length and flex stiffness were increased after dyeing, and tensile strength of waif i3l fabrics except Ramie was also increased. 2. Abrasion resistance was improved in Ramie and Hemp after dyeing but the rest of fabrics were decreased. 3. Crease resistance of dyed fabrics was roughly worse than that of undyed fabrics. 4. Air permeability remarkably increased after dyeing and this fact estabilished that the traditional Gal-01 was cool clothing. 5. Water repellency in Cotton 1 and Polyester rises but the rest of fabrics were not changed. Therefore it is found that this repellency related to the their fabric counts. 6. Blocking effect of UV light and visible ray was increased in all dyed fabrics. Especially dyed Cotton 1 and Polyester blocked UV light almost perfectly. 7. The colorfastness to soaping and sunlight was proved to less than 3 grade in all fabrics after dyeing. It indicates that this colorfastness became worse owing to dyeing. 8. The colorfastness to dry cleaning and water was decided to more than 3 grade in all fabrics. 9. The colorfastness of the dyed fabrics to sweat after exposing to man-made acid sweat solution was good so that was decided above 3 grade. However after exposing to man-made alkalic sweat solution it became worse owing to dyeing.

• 한국의류학회지
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• 제25권7호
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• pp.1193-1202
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• 2001

The goal of this research is to investigate the effect of fusible interlinings on the mechanical characteristics and appearance related values for the Lyocell fabrics. In this study, to establish optimum fusing conditions, peel strength of the fused fabrics depending on the fusing temperature, pressure and time was measured. Appearance related properties and mechanical characteristics of the fused fabrics ere determined. The reulst are as follows: In the fusing condition of $120^{\circ}C,\;3kgf/textrm{cm}^2$, 15sec, peel strength was excellent. Peel strength was excellent in the case of tencel/cotton fabric, with increasing cover factor of woven interlining, with twill and nonwoven interlining. Flex stiffness was increased in the case of tencel/cotton fabric, with increasing weight of woven interlining, with twill and nonwoven interlining. Drapability was excellent in the case of 100% tencel fabric, with decreasing weight of woven interlining, with plain and woven interlining. Crease recovery was excellent in the case of 100% tencel fabric, with increasing weight of woven interlining, with twill and woven interlining. Shear and bend properties were increased in the case of tencel/cotton fabric, with increasing weight of woven interlining, with plain and nonwoven interlining.

• 한국의류학회지
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• 제21권7호
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• pp.1196-1204
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• 1997

Cotton, rayon/cotton, and Tencel twill weave fabrics were used to investigate the effect of fiber types on the cellulase washing finish. And twill. basket, and derivative weave cotton fabrics were used to study the weave effect. Various fabrics were treated with neutral cellulase varying treatment times and with acid cellulase, stone, and stone-neutral cellulase respectively for two hours in a rotary washer. Weight loss decreased in the order of rayon/cotton> cotton> Tencel, and basket and derivative weave fabrics lost more weight than twill weave fabric. Color difference decreased in the order of cotton> Tencel> rayon/cotton, and twill weave fabric had larger color difference than derivative and basket weave fabrics. Back staining decreased in the order of cotton> rayon/cotton> Tencel, and twill weave fabric had larger back staining than derivative and basket weave fabrics. Tear strength retention decreased in the order of rayon/cotton> cotton> Tencet and twill weave fabric had larger tear strength retention than derivative and basket weave fabrics. Flex stiffness retention decreased in the order of cotton> Tencel> rayon/cotton, and in the order of derivative> twill> basket weave. In cotton fibers, damage of primary wall was observed. And the cellulase treatment on Tencel seemed to roughen the fabric surface slightly, and to fibril fibers along the fiber axis.

• Steel and Composite Structures
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• 제43권1호
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• pp.67-77
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• 2022

In the current study, ordinary design of Represstessed Pre-Flex (RPF) girder by classical beam theory and numerical model taking buckled shape into consideration were compared with field-survey data to find imperfections on the RPF girder before prestressing and after preflexion. It should be noted that the ordinary design do not consider deformed shape of steel girder in RPF beam. The deformed shapes of steel girder due to the incomplete fabrication that could be caused by self-weight, preflexion misalignment, existence of lateral bracing at mid-span and stiffness of reaction frame were found using a newly developed model which was verified against a deformation survey conducted on actual RPF girder in the field. The final observed deformed shapes of RPF after concrete shrinkage and before prestressing were classified into W, C and Unsymmetric shapes in regard to both survey and analytical results. The deformation survey showed negligible amount of unwanted deformation compared to the large size of the RPF girders. The shallower width of the bottom flange of steel girder caused amount of lateral torsional buckling under self-weight and preflexion thereby affecting the unwanted final overall shape of the RPF girders. However, it was found that the unwanted deformation of RPF girders by fabrication errors even though it is negligible compared to the size of the girder, caused unsymmetrical stress contours in concrete and additional tensile stress and raise some safety issues.

• 대한치과교정학회지
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• 제30권4호
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• pp.467-473
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• 2000

각형 호선이 edgewise 브라켓에 삽입되면 first, second order는 bending에 의해, third order는 torsion(비틀림)에 의해 3차원적인 force system이 발생한다. Bending에 관하여는 분석적 그리고 실험적인 많은 연구가 보고 되어 있는 반면 비틀림에 관해서는 상대적으로 많은 연구가 이루어 지지 않았다. 본 연구의 목적은 각형 와이어의 재료와 단면의 형태가 와이어의 비틀림 모멘트에 어떻게 영향을 주는지를 이론적, 실험적으로 밝혀서 임상적으로 적절한 모멘트를 가할 때 호선의 재료와 굵기를 합리적으로 선택할 수 있도록 하는데 있다. 실험재료로는 third order조절을 위해 가장 많이 사용하는 호선을 사용하였다. 크기별로 0.016x0.022, 0.017x0.025, 0.019x0.025인치 그리고 재료로는 stainless steel (Ormco), TMA(Ormco), NiTi(Ormco), 그리고 braided stainless steel(DentaFlex, Dentauum) 네 가지를 사용하여 총 12개의 조합을 사용하였다. Torsion formula를 이용하여 비틀림 강성 (torque/twist rate)을 계산하였고 torque gauge를 이용하여 비틀림 강성, 항복 비틀림 모멘트 (yield torsional moment), 그리고 최대 비틀림 모멘트 (ultimate torsional moment)를 측정하였다. Torsion formula에 의하면 비틀림 강성 (T/$\theta$)은 재료적인 특성(G)과 호선의 단면의 특성(J)에 비례하고 호선의 길이(L)에 반비례한다. 대부분의 실험치는 이론적인 값과 비슷하게 나타났다.

• Physical Therapy Rehabilitation Science
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• 제13권1호
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• pp.95-105
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• 2024

Objective: The purpose was to investigate changes in mechanical properties, range of motion, and grip strength of the forearm muscle in 13 students depending on the wrapping direction of the floss band. Design: A single-blind, crossover study Methods: Subjects were randomly assigned to the wrapping direction of the flossing band and then performed a concentric exercise of the wrist flexors using a Flex-Bar. Intervention A applied the flossing band in a right spiral direction, Intervention B applied the flossing band in a left spiral direction, and Intervention C performed the exercise alone. All subjects used their dominant right hand, and pre- and post-assessments were conducted between interventions. To analyze differences in changes between groups pre- and post-, all results were subjected to one-way ANOVA, followed by Scheffe's test as a post-hoc analysis. The paired samples t-test was used to analyze the difference between pre- and post-change within groups. Results: First, in the mechanical properties of the Flexor carpi ulnaris (FCU) muscle, interventions A and B significantly improved muscle tone and stiffness than intervention C (p<0.05), and intervention A showed a significant decrease in decrement (muscle elasticity) than intervention B (p<0.05). Second, interventions A and B showed significant improvement in grip strength than intervention C (p<0.05). Conclusions: The right spiral direction of the flossing band tended to increase the elasticity of the muscles compared to the left spiral direction. Therefore, in future studies, it is necessary to choose the direction of the flossing band to increase the elasticity of the muscles.

• 대한한의학원전학회지
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• 제3권
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• pp.151-217
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• 1989

In this thesis, I intend to study the translational and clinical interpretation through the theory of Ja-Yeol, and reached the following conclusions. 1. Liver-Heat-Disease due to absess of the function of expelling and lifting off, that Liver-Yang cannot lift up to upper-warmer, and stagnate liver. I think the symptoms of yellowish urine, abdominal pain, somnolence, fever belong to the syndrome of 'Gi-Bun(氣分)', and the symptoms of ravings with surprising, distending pain of hypochondrium, restless involuntary movement of the limbs, unable to lie flat belong to the syndrome of 'Hyeol-Bun(血分)'. 2. Heart-Heat-Disease due that 'Eum-Gi(陰氣)' in heart cannot lay down and reach to stagnate at heart, inner part. I think the symptoms of unjoy, acute cardiac pain, fidgetiness, well-nausea, headeche, reddish face, anhidrosis, etc. reveal with Heart-Heat-Disease. 3. Spleen-Beat-Disease due that 'Eum-Gi' in spleen cannot lay down and Yin of spleen changs heat. I think the symptoms of heaviness of head, cheek pain, fidgetiness, cyanosis, well-nausea, fever, not to let flex and reflex with back pain, diarrhea with abdominal pain, left and right cheek pain reveal with Spleen-Heat-Disease. I think symptoms of fever, diarrhea with abdominal pain belong to the syndrome of Yin-exhausion. 4. Lung-Heat-Disease due to that 'Eum-Gi' in lung cannot lay down. When 'Wi-Gi(衛氣)' stagnates at external part, I think, the symptoms of intolerance to wind and cold, yellowish fur, fever reveal. When Wi-Gi stagnates at lung, inner part, I think, the symptoms of dispnea with cough, pain on chest and back, unable to breath deeply, hydrosis and chilling reveal. 5. Kidney-Heat-Disease, in that the symptoms of back pain, leg aching, extreme thirst and frequently drink, fever, pain and stiffness of nape, cooling and aching leg, heat on plantar pedis, not trying to speak reveal is regarded external heat disease of 'Tai-Yang-Gyeong's(太陽經)' disease that asthenic fever open 'Tai-Yang-Gyeong' and lift by not enough of 'Yang-Gi(陽氣)' lifeing up from Kidney space, the water space of five elements.