• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.921-930
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• 2001

A new theoretical critical heat flux (CHF) model was developed for the forced convective flow boiling at high pressure, high mass velocity, and low quality. The present model for an intermittent vapor blanket was basically derived from the sublayer dryout theory without including any empirical constant. The vapor blanket velocity was estimated by an axial force balance, and the thickness of vapor blanket was determined by a radial force balance for the Marangoni force and lift force. Based on the comparison of the predicted CHF with the experimental data taken from previous studies, the present CHF model showed satisfactory results with reasonable accuracy.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.45-59
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• 2002

Evaluation of the mechanical properties of Bi-2223/Ag HTS tapes was carried out by the tension and bending tests. Most of the Bi-2223/Ag tapes retained critical current up to 10 kgf/mm$_2$ axial tension stress, and 0.2% tension strain at room temperature. Applied tension strain exceeding 0.3% in superconducting tapes at 77 K leaded to rapid degradation of the critical current. It was observed that the more filaments, the better axial tension property at 77 K, self-field The influence of bending strain on critical current degradation was revealed to be less sensitive for Bi-2223/Ag HTS tapes with a more number of filaments and higher silver ratio.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.291-298
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• 2001

When the compression members have the variable cross sections along their member axes, the determination of the elastic critical loads by classical methods becomes impossible and if possible involves complicated calculation only to obtain the approximate values of critical load. In this paper the elastic critical load coefficients of the tapered members with simply supported ends were determined by finite element method. And then the results were represented by simple algebraic equations of two parameters, a( =taper parameter) and m ( = sectional property parameter). One the basis of algebraic equations, the equivalent moment of inertia concept originally proposed by Bleich for a spesific case, are extended to the general cases.

• Progress in Superconductivity and Cryogenics
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• v.16 no.4
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• pp.7-16
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• 2014

Rare-earth barium copper oxide (REBCO) coated conductor (CC) tapes have already been commercialized but still possess some issues in terms of manufacturing cost, anisotropic in-field performance, $I_c$ response to mechanical loads such as delamination, homogeneity of current transport property, and production length. Development on improving its performance properties to meet the needs in practical device applications is underway and simplification of the tape's architecture and manufacturing process are also being considered to enhance the performance-cost ratio. As compared to low temperature superconductors (LTS), high temperature superconductor (HTS) REBCO CC tapes provide a much wider range of operating temperature and a higher critical current density at 4.2 K making it more attractive in magnet and coil applications. The superior properties of the REBCO CC tapes under magnetic field have led to the development of superconducting magnets capable of producing field way above 23.5 T. In order to achieve its optimum performance, the electromechanical properties under different deformation modes and magnetic field should be evaluated for practical device design. This paper gives an overview of the effects of mechanical stress/strain on $I_c$ in HTS CC tapes due to uniaxial tension, bending deformation, transverse load, and including the electrical performance of a CC tape joint which were performed by our group at ANU in the last decade.

• Progress in Superconductivity and Cryogenics
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• v.19 no.3
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• pp.18-22
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• 2017

Addition of $BaSnO_3$ (BSO) to $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) is reported to enhance the flux pinning property of GdBCO thick films. To investigate the effect of growth condition on the pinning properties, 700 nm-thick BSO-added GdBCO films deposited with varying temperatures and growth rates were prepared by using a pulsed laser deposition method. As the deposition temperature increases, the critical current density and the pinning force density show an improved field dependence up to $750^{\circ}C$ due to the increase in the formation of the a-axis growth and the BSO nanostructures. The films deposited at higher temperatures show degraded surfaces and as a result, degraded pinning behaviors. For the change in growth rate, the critical current density and the pinning force increase as the repetition rate increase at low magnetic fields, but this behavior is reversed in high magnetic fields. These results indicate that the film growth conditions significantly affect the formation of BSO nanostructures and the pinning properties of BSO-added GdBCO films.

• Progress in Superconductivity and Cryogenics
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• v.25 no.3
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• pp.34-37
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• 2023

The practical application of REBCO coated conductor (CC) tapes, vital for energy transmission (e.g., cable application) and high-field magnets (e.g., coil application), necessitates efficient and simple quality assessment procedures. This study introduces a systematic approach to assess the electromechanical properties of REBCO CC tapes under 77 K and self-field conditions. The approach involves customized tensile and bending tests that clarify the critical current (I_c) response of the CC tapes under mechanical loads induced by tension and bending. This study measures the retained Ic values of commercially available GdBCO CC tapes under 250 MPa tensile stress and 40 mm bending diameter. Through experimentation, the study demonstrates the resilience of these tapes and their suitability for applications. By presenting a simplified stress-based analysis and a bending test of the tapes, the study contributes to effective quality assessment methods for the development of practical superconducting products.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.11
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• pp.777-783
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• 2012

The hardness and strength test was performed to make the manufacturing process of SA213 P92 boiler pipe steel. And the microstructure change was studied to find out the cause of room temperature property of P92 steel, ie, low hardness and strength property. The room temperature property of P92 steel depends on the improper normalizing and cooling rate. Especially, Ferrite was formed and the steel had low hardness when the temperature was decreased slowly under the cooling rate $1^{\circ}C$/min after normalizing at the temperature around $A_{c1}$ to $A_{c3}$. The critical heat treatment temperature and cooling rate was over $900^{\circ}C$ and over $10^{\circ}C$/min to satisfy the minimum yield and tensile stress which was laid down by ASME Code.

• Journal of Arbitration Studies
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• v.29 no.3
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• pp.75-97
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• 2019

The growing importance of biological resources as sovereign rights to healthcare, energy, and food has sparked international discussions on Genetic Resources (GRs) and Traditional Knowledge (TK). As the bio-industry continues to grow, research and development utilizing patented biological resources are advocated. Currently, World Intellectual Property Organization (WIPO) is actively discussing GRs and TK, and an effective response to national interest has been sought. Of late, there have been growing disputes over issues like ownership, control, and access and benefit-sharing between indigenous peoples and users of GRs and TK resources. Resolution of disputes concerning GRs and TK are thus becoming critical not only to stakeholders such as the indigenous peoples and corporations, but also to third-party users. Due to the weakness of the current IP and court system however, such disputes are not addressed adequately. This paper will address the use of Alternative Dispute Resolution (ADR), which is an out-of-court dispute resolution system, on conflicting issues regarding GRs and TK. It will consider the WIPO as a forum for ADR and ADR for GRs and TK disputes and it will seek both parties in the dispute to benefit from the use of the ADR process.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.339-347
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• 2008

This study was carried out to assess quantitatively the safety of a tunnel by using critical strains in the ground. Critical strain is a new material property of the ground. It can be applied as deformation limits in the ground due to excavation using the measured displacement at the tunnel construction site. To achieve this purpose, the critical strain concept was reviewed and applied to assess the tunnel safety. First of all, the calculated excavation displacements of a circular tunnel by commercial programs were investigated and inputted into a feedback analysis module to calculate strains in the ground. Then the safety of tunnels was evaluated based on the critical strain concept. Subsequently the measured displacements obtained in the field are utilized practically to assess the safety of tunnels using the critical strain concept. Through this study, it was confirmed that the critical strain concept is useful to assess the safety of tunnels quantitatively.

• Korean Journal of Materials Research
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• v.24 no.11
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• pp.625-631
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• 2014

To investigate the deformation properties of TiC-(5-20) mol% Mo solid solution single crystals at high temperature by compression testing, single crystals of various compositions were grown by the radio frequency floating zone technique and were deformed by compression at temperature from 1250K to 2270K at strain rates from $5.1{\times}10^{-5}$ to $5.9{\times}10^{-3}/s$. The plastic flow property of solid solution single crystals was found to be clearly different among a three-temperature range (low, intermediate and high temperature ranges) whose boundaries were dependent on the strain rate. From the observed property, we conclude that the deformation in the low temperature range is controlled by the Peierls mechanism, in the intermediate temperature range by the dynamic strain aging and in the high temperature range by the solute atmosphere dragging mechanism. The work softening tends to become less evident with an increasing experimental temperature and with a decreasing strain rate. The temperature and strain rate dependence of the critical resolved shear stress is the strongest in the high temperature range. The curves are divided into three parts with different slopes by a transition temperature. The critical resolved shear stress (${\tau}_{0.2}$) at the high temperature range showed that Mo content dependence of ${\tau}_{0.2}$ with temperature and the dependence is very marked at lower temperature. In the higher temperature range, ${\tau}_{0.2}$ increases monotonously with an increasing Mo content.