• Journal of Hydrospace Technology
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• v.1 no.1
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• pp.125-145
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• 1995

In this paper, three kinds of the existing idealized structural units, namely the idealized beam-column units the idealized unstiffened plate unit and the idealized stiffened plate unit are expanded to deal with the excessive tension-deformation effects. A simplified mechanical model far the stress-strain relationship of steel members under tensile load is suggested. The 1/3-scale hull model for a leander class frigate under sagging moment tested by Dow is analyzed, and it is shown that the excessive tension-deformation is a significant factor affecting the progressive collapse behavior, particularly in the post-collapse range.

• Smart Structures and Systems
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• v.29 no.3
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• pp.475-484
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• 2022

The loss of cable tension for civil infrastructure reduces structural bearing capacity and causes harmful deformation of structures. Currently, most of the structural health monitoring (SHM) approaches for cables rely on contact transducers. This paper proposes a cable tension identification technology using percussion sound, which provides a fast determination of steel cable tension without physical contact between cables and sensors. Notably, inspired by the concept of tensioning strings for piano tuning, this proposed technology predicts cable tension value by deep learning assisted classification of "percussion" sound from tapping a steel cable. To simulate the non-linear mapping of human ears to sound and to better quantify the minor changes in the high-frequency bands of the sound spectrum generated by percussions, Mel-frequency cepstral coefficients (MFCCs) were extracted as acoustic features to train the deep learning network. A convolutional neural network (CNN) with four convolutional layers and two global pooling layers was employed to identify the cable tension in a certain designed range. Moreover, theoretical and finite element methods (FEM) were conducted to prove the feasibility of the proposed technology. Finally, the identification performance of the proposed technology was experimentally investigated. Overall, results show that the proposed percussion-based technology has great potentials for estimating cable tension for in-situ structural safety assessment.

• Journal of the Korean Applied Science and Technology
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• v.4 no.2
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• pp.43-48
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• 1987

Isoelectric point and surface tension of twelve of the alkylcarboxy betaines such as 2-(trimethylammonio) dodecanoate, 2-(trimethyammonio) tetradecanoate, 2-(trimethylammonio) hexadecanoate, (dimethyldodecylammonio)ethanoate, (dimethyltetradecylammonio)ethanoate, (dimethylhexadecylammonio) ehtanoate, 2-(dimethylododecylammonio) propanoate, 2-(dimethyltetradecylammonio)proopanoate, 2-(dimethylhexadecylammonio)propanoate, 2-(dimethyltetradecylammonio)-3-phenyl propanoate, 2-(dimethyltetradecylammonio)-3-phenyl propanoate are tested. From the measurement of the isoelectric point, it was found that the isoelectric point were leaned toward the alkaline zone for c-alkylarbrxybetaines, and toward the acidic zone for N-alkylcarboxybetaines. At the range of the carboxybetaine concentration $2\;{\times}\;10^{-2}{\sim}2\;{\times}\;10^{-5}$mole/l, the surface tension of the aqueous solution were decreased to 30-38 dyne/cm, showing the tendency that the ability of lowering the surafce tension was depending on the increase of carbon atom number in the lipophilic alkyl chain. The critical micelle concetration measured by the surface tension and concentration curves have been found at the range of $10^{-2}{\sim}10^{-5}$mole/l.

• Journal of the Korean Chemical Society
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• v.8 no.1
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• pp.1-4
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• 1964

Relative surface tensions of aqueous solutions of KCl, KI and NaI have been measured at 25$^{circ}C$(30$^{circ}C$ for KCl) over a concentration range of 0.0001 to 3M solution. It was observed that there was a minimum in the surface tension-concentration curve for the extremely dilute solutions. Appearance of the minimum has been reported for the other salt solutions so far reported. At moderate and high concentration, these three salts increase the surface tension of water almost linearly as concentration increased, and behaved as a typical "capillary inactive substance", whereas they acted as a capillary active substance in very dilute solutions. Since the Onsager-Samaras equation for the surface tension as a function did not agree with the experimental data, the following empirical equations for the whole concentration range used were obtained. ${\sigma}_r\;=\;1\;+\;0.00072{\sqrt{c}}\;-\;0.0011c\;+\;0.023c^2\; for\;KCl\;at\;30^{\circ}C$ ${\sigma}_r\;=\;1\;+\;0.0077{\sqrt{c}}\;-\;0.0015c\;+\;0.024c^2\;for\;KI\;at\;25^{\circ}C$ ${\sigma}_r\;=\;1\;+\;0.00011{\sqrt{c}}\;-\;0.0090c\;+\;0.077c^2\;for\;NaI\;at\;25^{\circ}C$

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.156-165
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• 2009

This study is to consider the character of cables in six World-Cup stadiums constructed in 2002 and to inspect problems on measurement natural frequencies interpretation and application of existing theory. The results of the experiment were shown that it was possible to determine the tension force of the real cables with an accuracy of 8% by taking the cable bending stiffness. But for the range of cable affected greatly by bending stiffness(${\xi}{\leq}7$), it was appeared the tendency to increase estimated error and was considered to need additional study of this range. Estimated tension error could not be improved so much in comparison to the case using single mode of vibration even through multiple modes of vibration were used.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.32-38
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• 1999

A biosurfactant produced by Tsukamurella sp. 26A was purified by procedures including acid precipitation, ethylacetate extraction, and adsorption chromatography. The purified biosurfactant reduced the surface tension of water from 72 mN/m to 30 mN/m at a concentration of 250 mg/l, whereas the minimum interfacial tension against n-hexadecane was lowered to 1.5 mN/m at a concentration of 40 mg/i. The compound stabilized oil-in-water emulsions with a variety of commercial oils and had strong emulsification and stabilization activities when compared to those of commercial emulsifiers and stabilizers. Surface tension was stable over a broad range of pH (2-12) and temperature ($100^{\circ}C$, 3h). The biosurfactant was identified as glycolipid having a hydrophilic moiety of trehalose.

• Journal of Families and Better Life
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• v.16 no.4
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• pp.83-83
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• 1998

The purpose of this study is to investigate interpersonal support, tension in lifechanges & satisfaction. The selected sample is composed of 387 housewives in ChongJoo city. SAS pc program was used for the statistical analysis of the data. Data was analyzed by frequency, F-test, percentage, mean, Duncan's Multiple Range Test, Pearson's correlation coefficient, Regression Analysis. Major findings as follows: 1)At wedding & funeral ceremony, kin networks of her parents & parents-in law side were variables to have influence on tension in life changes. And the number of social organization participated were a variable to have influence on the satisfaction. The age of couple, education of couple, duration of marriage, income, family lifecycle, the number of children, pattern of family were variables to influence tension in life changes, but were not variables to influence on the satisfaction. 2) At usual or wedding & funeral ceremony, kin networks of her parents side were variables to influence on instrumental & companionship support. And the number of friends was a variable to influence on companionship & informational support. The number of neighbors was a variable to influence on instrumental, companionship & informational support. The number of social organization participated was a variable to influence on companionship & emotional support. The age of couple, education of couple,income, duration of marriage, family life cycle, number of children, family size, family type were variables to influence on interpersonal support. 3)The relationship between tension and satisfaction in life changes was negative, and between instrumental support and satisfaction was negative also. But between companionship support and satisfaction was positive relationship and between tension of personal &social life and instrumental support was positive relationship. The relationship between tension of marriage life and companionship support was negative and between tension of family life and information support was negative relationships. The received companionship support was lower tension in life changes than not received it. But the received instrumental support was higher tension of personal & social life. The received companionship & informational support was higher satisfaction than not received them. But the received instrumental support was lower satisfaction than not received it. 4) Instrumental & companionship support, at usual kin network of her parents in taw side, at wedding & funeral ceremony kin network of her parents side,were variables to influence on tension in life changes. Instrumental, companionship& informational support, at wedding & funeral ceremony kin network of her parents side, were variables to influence on the satisfaction

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1127-1134
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• 2002

The present paper provides an engineering J estimation equation for surface cracked plates under combined bending and tension. The proposed equation is based on the reference stress approach, and the most relevant normalising loads to define the reference stress for accurate J estimations are given for surface cracked plates under combined bending and tension. Comparisons with J results from extensive 3-D FE analyses, covering a wide range of crack geometry, plate geometry and loading combination, show overall good agreement not only at the deepest point but also at arbitrary points along the crack front. for pure tension, agreement between the estimated J and the FE results is excellent, even at the surface point. On the other hand, for pure bending and combined bending and tension, the estimated J values become less accurate for locations close to the surface point. Thus the results in this paper will be useful to assess short-term fracture or low cycle fatigue of surface defects in plates under combined bending and tension.

• International Journal of Concrete Structures and Materials
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• v.10 no.2
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• pp.143-147
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• 2016

In recent years, some modifications were introduced in the stress-strain relationship of the steel in order to develop a more efficient shear model for reinforced concrete members. The last contribution in this sense corresponding to the Refined Compression Field Theory (RCFT, 2009); this theory proposed a steel constitutive model that has account the tension stiffening area prescribed by technical codes, what simplifies all the design process. However, under certain design conditions supported by such codes, the RCFT model does not provide a real (non-complex) solution for the steel yield strain when the prescribed tension stiffening area is considered; then the load-strain response cannot be computed. In this technical note, the tension stiffening area is fixed in order to guarantee the application of the embedded steel constitutive model for all the standard design range.

• Steel and Composite Structures
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• v.9 no.2
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• pp.173-189
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• 2009

This paper presents a study on the behavior and design of bolted stainless steel plates under in-plane tension. Using an experimentally validated finite element (FE) program strength of stainless steel bolted plates under tension is examined with an emphasis on plate bearing mode of failure. A numerical parametric study was carried out which includes examining the behavior of stainless steel plate models with various proportions, bolt locations and in two different material grades. The models were designed to fail particularly in bolt tear-out and material piling-up modes. In the numerical simulation of the models, non-linear stress-strain material behavior of stainless steel was considered by using expressions which represent the full range of strains up to the ultimate tensile strain. Using the results of the parametric study, the effect of variations in bolt positions, such as end and edge distance and bolt pitch distance on bearing resistance of stainless steel bolted plates under in-plane tension has been investigated. Finally, the results obtained are critically examined using design estimations of the currently available international design guidance.