• Title/Summary/Keyword: 항복값

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Rheological Properties of Radish Juice Concentrates (무우쥬스 농축액의 Rheological Properties)

  • Lee, Se-Eun;Lee, Boo-Yong;Jin, Jae-Soon;Kim, Dong-Man;Kim, Kil-Hwan
    • Korean Journal of Food Science and Technology
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    • v.24 no.3
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    • pp.261-265
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    • 1992
  • To improve preservation and utilization of radish juice concentrates, radish juice were concentrated by reverse osmosis(RO) and thin layer evaporator(TLE) and their rheological properties were investigated. Radish juice concentrates were considered as nowtonian fluids. The apparent viscosity of conc. 1 (Heat treatment radish juice, concentrated by TLE), conc. 2 (Raw radish juice, concentrated by TLE), conc. 3 (Heat treatment radish juice, concentrated by RO) were 0.0503, 0.0578 and 0.0655 Pa.s at 10(1/s), respectively. The yield stress of these concentrates were ranged from 0.0001 to 0.0580 Pa. The activation energy for the flow of the radish juice conc. 1 were increased from 2.7057 to $4.1159{\times}10^4KJ/kg.mol$ by increasing concentration of radish juice.

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Effect of Phosphate on Rheological Properties of Rice Starch Suspension (인산염이 쌀전분 현탁액의 리올로지에 미치는 영향)

  • Kim, Il-Hwang;Kim, Sung-Kon;Lee, Shin-Young
    • Korean Journal of Food Science and Technology
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    • v.19 no.3
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    • pp.239-244
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    • 1987
  • Rheological properties of 5% starch suspension were investigated using a capillarity tube viscometer. Nonglutinous and glutinous rice starch suspensions at $30-60^{\circ}C$, and $30-55^{\circ}C$, respectively, had no yield stress and showed dilatant flow behavior in the absence or presence of phosphate. However, flow behavior of nonglutinuous starches at $65^{\circ}C$ and glutinous starch at $60^{\circ}C$ was pseudopalastic. Flow activation energies for rice starch suspensions were 0.88-1.45 kcal/mole at $30-50^{\circ}C$ and about 45-73 kcal/mole $60-65^{\circ}C$. Flow activation energy in the presence of phosphate was 90-182 kcal/mole at $60-65^{\circ}C$. Akibare starch had the highest activation energy, and glutinous starch the lowest.

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Development of Manufacturing Process of Pure Titanium Wire to make Eyewear Frame (안경용 순티타늄 wire 제조 공정개발)

  • Choi, Gye-Hun;Kim, Sang-Yeoun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.3
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    • pp.1105-1110
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    • 2011
  • After pure titanium Ingot(G2) with 400mm in diameter was manufactured, the analysis of its ingredients showed that the oxygen content was 0.073wt% and the iron content was 0.03wt%, which made ASTM Gr.2 standardization satisfactory. The processed titanium ingot produced 42mm wire rod, and hot rolling of 18th phase produced 9mm wire rod. The hardness analysis of 15.8mm wire rod, which was processed in hot rolling of 10th phase from the surface to the center, resulted in almost constant value with Hv150~200. The last 9mm wire rod had a different yield strength and elongation percentage depending on the temperature as it was led in to a hot roller. However, tensile strength revealed an approximate value and made ASTM B863 standardization satisfactory.

Ultimate Behavior of Reinforced Concrete Hyperbolic Cooling Tower (R/C 쌍곡 냉각탑의 극한 거동)

  • Min, Chang Shik;Kim, Saeng Bin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.4
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    • pp.59-70
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    • 1992
  • Inelastic nonlinear behavior of a hyperbolic cooling tower under wind loading is studied using a finite element program developed on a Cray Y-MP. Convergence studies for the elastic and inelastic analyses are performed using three mesh models. It is shown that the mesh convergence plays an important role in accurately predicting the inelastic behavior of a cooling tower. Even though the cooling tower resists the applied forces through membrane stresses, it is found that the bending stresses play an important role in the failure and behavior of the cooling tower. The present analysis gives a shape factor of 1.48, which indicates a significant redistribution of meridional stresses. It is further evidenced by the distribution of meridional reinforcement yielding which reaches up to $30^{\circ}$ from the windward meridian. The present practice of using elastic analysis for calculating the design stresses appears to be at least safe and conservative. A more comprehensive study should lead to conclusions that would allow use of a higher-than-one shape factor, thus requiring less meridional reinforcement than the present design method does.

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FEA of Beam-Column Connection with Bolted Web (웨브를 볼트로 접합한 보-기둥 접합부의 유한요소해석)

  • Shin, Kyung-Jae;Lim, Bo-Hyuk;Lee, Swoo-Heon;Choi, Sung-Mo
    • Journal of Korean Society of Steel Construction
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    • v.23 no.3
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    • pp.305-316
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    • 2011
  • As the building structures are higher and bigger, the high-performance steels of high strength, toughness, and low yield ratio had been required and developed. In this paper the behavior of the moment connection with bolted web and high strength steel was studied by using the finite-element analysis computer program of ABAQUS. The analysis model is based on the test results and the same cyclic load history was applied at the FE(Finite Element) model until it failed in the test. Through the FEA, several indicators hardly measured from the test were acquired. These indicators related to stress and strain were selected from three plastic rotation stages: 0.003 rad, 0.03 rad, and final failure rotation. Specifically, at the final failure stage, the strain indicators producing the full plastic behavior were suggested as a mechanical property for steel.

Seismic Safety Enhancement of Damage-Controlled Reinforced Concrete Frames (손상제어 설계된 철근 콘크리트 프레임의 내진력 향상)

  • ;;Kim, Se Yoll
    • Computational Structural Engineering
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    • v.4 no.3
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    • pp.89-97
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    • 1991
  • Conventional aseismic design methods of R/C frame all but disregard the state of damage over the entire building frame. This paper presents an automated damage-controlled design method for R/C frames which aims at an uniform energy dissipation rate throughout the building frame, so that the resulting damage is uniformly distributed as much as possible over all element. The accuracy of the basic hystertic model and the damage model for R/C members is verified by reproducing the experimental load-deformation curves of one-bay one-story frames. Application of this design method to various frame structures indicate that 1) regardless of the structural properties or input earthquake characteristics, damage-controlled frames generally survive more severe earthquake excitations and suffer less damage than conventionally designed frames, and 2) member yielding strength in the lower stories of damage-controlled frames is larger than that for conventionally designed frames, while the trend is opposite in the upper stories.

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Evaluation of Foil Strength by Full Scale Strain Measurement (실선 계측에 의한 수중익 강도 평가)

  • I.H. Choe;K.Y. Chung;O.H. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.32 no.3
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    • pp.37-43
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    • 1995
  • The procedure and the results of the full scale strain measurement of the long-range high-speed foil catamaran are described. The wave induced stresses at the center struts of the foils were measured during the sea trials in order to evaluate the hydrodynamic force acting on the foils and to verify the structural safety of the foil structures. From the statistical properties of the measured response of the stress, the most probable maximum values of the lift force and the stresses at the foils in service life of the ship are predicted and compared with the design parameters of the foils which were applied in the design of the subject ship. The available prediction processes of the measured stress are studied and the results of the applied processes are compared with each other.

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Study on the Improvement of Strength Capacity for Glulam-to-bolt Connection (집성재 볼트 결합부의 강도 성능 개선에 관한 연구)

  • Kim, Gwang-Chul
    • Journal of the Korean Wood Science and Technology
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    • v.33 no.6 s.134
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    • pp.31-37
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    • 2005
  • This research investigated the increase in strength capacity for the difference of various connection conditions. Connections were constructed with a main member, glulam and side members, 3 mm steel plates. Connections were varied in the number of inserted 1 mm steel plate. The strength capacity considerably increased by inserting the very thin steel plate within structural glulam connection. Glulam connections were classified as the number of inserted steel plate, group A was none, group B was one, group C was two, and group D was three. Ultimate and design values of the group B were 18% and 13% greater than the group A, the group C were 27% and 20% than the group A, and the group D were 33% and 24% than the group A. However, the increase in strength capacity and the additional difficulty should be considered on economic and technical view.

Thixotropic Properties of Gelatinized Rice Starch Solutions (쌀 전분 호화액의 틱소트로픽 성질)

  • Kim, Ju-Bong;Kim, Young-Suk;Lee, Shin-Young;Pyun, Yu-Ryang
    • Korean Journal of Food Science and Technology
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    • v.16 no.4
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    • pp.451-456
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    • 1984
  • Rheological properties of gelatinized rice starch solutions were investigated with Brookfield rotational viscometer. The 8% starch solution showed thixotropic behavior with yield stress. The alkali gelatinized starch was more thixotropic than the thermal gelatinized one. The time dependent characteristics of starch solutions followed Tiu's model. The value of rate constant $(a_1)$ in Tiu's model increased linearly with shear rate, and was exponentially dependent on concentration and temperature. Temperature dependency of rate constant and apparent viscosity followed Arrhenius type equation and the activation energy were about 14.3 and 6.8 Kcal/g mole, respectively. The $a_1-value$ was found to be useful to evaluate changes in structaral decay on the shearing time of gelatinized rice starch solutions.

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The Characteriastics of Viscosity Behavior of EMC for Semi-conductor Encapsulant - Containing One Kind of Spherical Silica (반도체 봉지재용 EMC의 점도거동 특성 - 한 종류의 구형 실리카 포함)

  • Kim, In Beom;Lee, Myung Cheon;Lee, Euy Soo
    • Applied Chemistry for Engineering
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    • v.10 no.8
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    • pp.1175-1179
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    • 1999
  • The rheological properties of highly filled epoxy molding compound(EMC) for semi-conductor encapsulants are greatly affected by the content of filler loaded. In this study, the change of viscosity of EMC for semi-conductor encapsulants with the filler content was investigated. Also, both of Cox-Merz and modified Cox-Merz equations were applied to convert the viscosity change as a function of frequency to that of shear rate. It was ovserved that shear thinning and yield stress occured at high filler contents and that the Cox-Merz equation could not be applied at high filler contents because of the difference of viscosity according to the various strains. When the modified Cox-Merz equation was applied, the all the curves having different strain tend to be represented by one master curve, even though some deviation was obseved at high filler content and strain.

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