• Title/Summary/Keyword: Under-tension system

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Cardiovascular Effects of Propofol Infused for Maintenance of Anesthesia in Dogs (개에서 Propofol 점적투여율 변화가 심혈관계에 미치는 영향)

  • 권영삼;장광호;장환수;박현정;임재현;오태호;엄기동;장인호
    • Journal of Veterinary Clinics
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    • v.19 no.2
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    • pp.199-203
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    • 2002
  • Cardiovascular effects of propofol, were assessed after premedication with xylazine(1.0 mUkg, IM) under oxygen supply(200 ml/kg/min) via a endotracheal tube. Twelve adult mixed-breed dogs were divided into four groups; 0.2(Group 1), 0.4(Group 2), 0.6(Group 3) and 0.8 mg/kg/min(Group 4) of propofol respectively. Arterial blood pressure and electrocardiogram were monitored with a physiograph after an arterial catheter was inserted into the femoral artery. pH, arterial carbon dioxide tension($PaCO_2$and arterial oxygen tension($PaO_2$) were evaluated with arterial blood collected through the inserted catheter. Diastolic arterial pressure, systolic arterial pressure and mean arterial pressure were decreased slightly in Group I IIand III, but decreased significantly in Group IV. They were increased rapidly after stopping propofol infusion in Group IV pH was maintained in normal range in Group I, II and m, but was decreased in proportion to time passing in Group IV. $PaCO_2$ was increased significantly only in Group IV but $PaO_2$ was maintained in normal range in all groups Although heart rate was recorded in normal range for 90 minutes, arythmia was noted after stopping propofol infusion in all groups. It was concluded that propofol depressed the cardiovascular system in proportion to infusion dosage, and 0.8 mg/kg/min of propofol infusion rate was not appropriated in canine anesthesia with xylazine premedication.

Effect of Solvents on the Structure of Electrospun PVP Fiber (PVP의 전기방사 섬유 제조에서 용매에 따른 구조 변화)

  • Park, Ju-Young;Lee, In-Hwa
    • Applied Chemistry for Engineering
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    • v.19 no.5
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    • pp.484-490
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    • 2008
  • Electrospun of PVP (polyvinylpyrrolidone) ultra fine fibers were fabricated using various solvents including methanol, ethanol, 2-propanol, butanol, acetone, methylene chloride, and DMF, which possess different properties such as boiling point, dielectric constant, and dipole moment. Electrospun PVP fiber was influenced by viscosity, conductivity, and surface tension of spinning solution. Therefore, the electrospun PVP fiber was successfully prepared under critical conditions of viscosity > $0.114kg/m{\cdot}s$, conductivity > 1.02 mS/m, surface tension < 30.0 mN/m. In case of an ethanol solvent system, average diameter of PVP fiber increased from 1701 nm to 5454 nm as increased the applied voltage from 10 kV to 20 kV.

The Study of Characteristics of Electrolytic Water (전해수의 특성에 관한 연구)

  • Lee, Chan-Woo;Bae, Kie-Seo
    • Textile Coloration and Finishing
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    • v.18 no.6 s.91
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    • pp.43-48
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    • 2006
  • Electrolytic water(EW), studied in recent decades in the Japan, Russia and United State of America, have shown promise as a method of disinfection whereby low levels of free chlorine, sodium hypochlorite, or hypochlorous acid may be produced in situ in Nacl-containing solution. These methods have shown promise in destruction of microorganisms in medical, dental environment, and in the agriculture and food industry. A recently EW treatment system was evaluated for reducing scouring agent and other surfactants in the washing and scouring process of textile industry Unfortunately, there is, to my knowledge, no serious studies of the properties of EW for textile industry In order to study the characteristics of EW and confirm the possibility of applications in textile industry processes, the pH, surface activity, penetration force, surface tension, and contact angle of EW was measured under various conditions. In general terms, What all this shows is that there is fundamental difference between the properties of EW and that of distilled water.

Analysis of Process Characteristics by Single Yarn Production in Ring Spinning (링 정방공정에서 단사제조에 의한 공정특성 분석)

  • Lee, Choon-Gil;Oh, Bong-Hyo;Park, Sung-Diuk
    • Textile Coloration and Finishing
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    • v.9 no.5
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    • pp.1-9
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    • 1997
  • In the single yarn spinning process by the ring spinning system, the finer the fineness of yarn and the lower the twist coefficient, the lower the breaking strength and breaking elongation. The change of yarn specific volume to yarn number agreed with Peirce's formula in the range of Ne 50 to 70, but above that range the values of the experiment are higher than that of the formula. The change of diameter of yarn to the reciprocal of the square root of yarn number agreed with Peirce's formula in the range of under 0.14, but above that value the values of the experiment are higher than that of the formula. In breaking strength variation according to twist constant of single yarn, as the twist coefficient increased, breaking strength increased. At 5.8∼6.0 of twist coefficient the maximum breaking strength was shown, but above that value breaking strength decreased. Breaking elongation also showed a similar tendency. But at 6.0∼6.5 of twist coefficient the maximum breaking elongation was shown. Also spinning tension increased as twist coefficient increased. Twist coefficient, breaking strength and breaking elongation according to the number of coils stayed almost the same. Yarn spinning tension according to the number of coils at the maximum of diameter was the lowest value. The speed of the traveller at the maximum of diameter was the highest value.

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Experimental investigation of interlaminar mechanical properties on carbon fiber stitched CFRP laminates

  • Iwahori, Yutaka;Ishikawa, Takashi;Watanabe, Naoyuki;Ito, Akira;Hayashi, Yoichi;Sugimoto, Sunao
    • Advanced Composite Materials
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    • v.16 no.2
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    • pp.95-113
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    • 2007
  • Experimental investigations of interlaminar mechanical properties for carbon fiber reinforced plastic (CFRP) laminates were carried out using aramid fiber ($Kevlar^{(R)}$-29 1000d) and carbon fiber (TR40-1K 612d, Mitsubishi Rayon) stitching. Various carbon fiber (CF) stitch densities were used to prepare a number of CF stitched CFRP laminates for double cantilever beam (DCB) tests. An insert tongue-type loading fixture, developed by the Japan Aerospace Exploration Agency (formerly the National Aerospace Laboratory of Japan), was also employed in the DCB test. Interlaminar tension tests were carried out under an out-of-plane directional loading using a single CF stitch thread in the CFRP laminates. The DCB test results clarified that the relationship between the volume fractions of the CF stitch thread ($V_{ft}$) and mode I critical energy release rate ($G_{Ic}$) showed a mostly linear function with a higher gradient than that of the $Kevlar^{(R)}$ stitched CFRP laminates. The CF stitched CFRP tension test results indicated that the consumption energy per unit area ($E_i$) was larger than that of $Kevlar^{(R)}$ stitched CFRP laminates.

A Study on the Ink Transfer Using the Roughness and Substrate Energy of Substrate in Roll to Roll Printing Systems (롤투롤 인쇄 시스템에서의 기판 소재의 거칠기와 표면에너지를 이용한 잉크 전이에 대한 연구)

  • Shin, Kee-Hyun;Kim, Ho-Joon
    • Journal of the Semiconductor & Display Technology
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    • v.9 no.2
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    • pp.103-109
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    • 2010
  • An ink transfer is modeled and experimentally verified using roll-to-roll electric direct gravure printing process. The ink transfer model based on the physical mechanism for the maximum ink transfer rate is proposed, and experimented by the electric printing machine in FDRC for the relations of the maximum ink transfer rates to the printing pressure, the operating speed, the operating tension, the surface roughness of substrates, and the contact angle between substrate and silver ink. The free ink split coefficient and immobilized ink under the maximum ink transfer rate are calculated by the physical parameter in a printing process and contact angle between substrates and ink. Numerical simulations and experimental studies were carried out to verify performances of the proposed ink transfer model. Results showed that the proposed ink transfer model was effective for the prediction of the amount of transferred ink to the substrate in a direct gravure printing systems.

Evolution of post-peak localized strain field of steel under quasi-static uniaxial tension: Analytical study

  • Altai, Saif L.;Orton, Sarah L.;Chen, Zhen
    • Structural Engineering and Mechanics
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    • v.83 no.4
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    • pp.435-449
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    • 2022
  • Constitutive modeling that could reasonably predict and effectively evaluate the post-peak structural behavior while eliminating the mesh-dependency in numerical simulation remains to be developed for general engineering applications. Based on the previous work, a simple one-dimensional modeling procedure is proposed to predict and evaluate the post-peak response, as characterized by the evolution of localized strain field, of a steel member to monotonically uniaxial tension. The proposed model extends the classic one-dimensional softening with localization model as introduced by (Schreyer and Chen 1986) to account for the localization length, and bifurcation and rupture points. The new findings of this research are as follows. Two types of strain-softening functions (bilinear and nonlinear) are proposed for comparison. The new failure criterion corresponding to the constitutive modeling is formulated based on the engineering strain inside the localization zone at rupture. Furthermore, a new mathematical expression is developed, based on the strain rate inside and outside the localization zone, to describe the displacement field at which bifurcation occurs. The model solutions are compared with the experimental data on four low-carbon cylindrical steel bars of different lengths. For engineering applications, the model solutions are also compared to the experimental data of a cylindrical steel bar system (three steel bars arranged in series). It is shown that the bilinear and nonlinear softening models can predict the energy dissipation in the post-peak regime with an average difference of only 4%.

A Study on Creep Effect of Synthetic Fiber Rope Mooring System on Motion Response of Vessel and Tension of Mooring Line (섬유로프 계류시스템의 크리프 효과가 부유체의 운동응답 및 계류선의 장력 변화에 미치는 영향에 관한 연구)

  • Park, Sung Min;Lee, Seung Jae;Kang, Soo Won
    • Journal of the Society of Naval Architects of Korea
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    • v.54 no.2
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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.

Effect of Cosurfactant on Microemulsion Phase Behavior in NP7 Surfactant System (보조계면활성제가 NP7 계면활성제 시스템의 마이크로에멀젼 형성에 미치는 영향에 관한 연구)

  • Lim, HeungKyoon;Lee, Seul;Mo, DaHee;Lim, JongChoo
    • Applied Chemistry for Engineering
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    • v.22 no.4
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    • pp.416-422
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    • 2011
  • In this study, the effect of cosurfactant on the phase equilibrium and dynamic behavior was studied in systems containing NP7 nonionic surfactant solutions and nonpolar hydrocarbon oils. All cosurfactants used during this study such as n-pentanol, n-octanol and n-decanol acted as a hydrophobic additive and thus promoted the transition from an oil in water (O/W) microemulsion (${\mu}E$) in equilibrium with an excess oil phase to a three-phase region containing excess water, excess oil, and a middle-phase microemulsion and further to a water in oil (W/O) ${\mu}E$ in equilibrium with the excess water phase. The transition temperature was found to decrease with both increases in the chain length and amount of addition of a cosurfactant. Dynamic behavior studies under O/W ${\mu}E$ conditions showed that an oil drop size decreased with time due to the solubilization into micelles. On the other hand, both the spontaneous emulsification of water into the oil phase and the expansion of oil drop were observed under W/O ${\mu}E$ conditions because of the diffusion of surfactant and water into the oil phase. Under conditions of a three-phase region including a middle-phase ${\mu}E$, both the rapid solubilization and emulsification of the oil into aqueous solutions were found mainly due to the existence of ultra-low interfacial tension. Dynamic interfacial tension measurements have been found to be in a good agreement with dynamic behavior results.

Cable Tension Force Management Using Vibration Method at Cable Stayed Bridge Construction Stages (진동법을 이용한 사장교 시공단계별 케이블 장력관리)

  • Park, Yeon-Soo;Cheon, Dong-Ho;Cheon, Yang-Bae;Kang, Kyoung-Koo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.4
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    • pp.127-134
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    • 2005
  • Design and construction of long-span bridge are recently increasing by development of computer technology. Specially, cable stayed bridge and suspension bridge having cable component are representative of long-span bridge may do. Therefore, this paper a present a methodology for cable tension force monitoring in cable-stayed bridge under construction using acceleration data acquired by the vibration method. To improve accuracy construction, all stay cables are measured, according to 4-step construction stage and change of temperature.