• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.697-706
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• 2006

Tower crane's wall tie is generally used for extending of mast height according to rising of lifting height. In order to get wall tie member force this problem, this study concerning wall tie is based on load data described in manual book of 290HC model. This study made the equation of wall tie member force and computer programming for calculating wall tie member force and then get ${\theta}-P$ curves(angle-wall tie force). After considering the ${\theta}-P$ curves, optimum angle range ($48.4^{\circ}{\sim}77.2^{\circ}$) about wall ties (A), (C) members was obtained. Member force of wall tie (B) was changed from tension to compression or from compression to tension at $74^{\circ}$ in service and $54^{\circ}$ in out of service. When both horizontal force($H_A$) and torsional moment ($M_D$) were varied from (+) to (-), wall tie force(A, B, C) were changed almost symmetrically about ${\theta}$-axis. Because this study was based on wall tie analysis conditions, wall tie members in symmetric and ideal geometry shape used for analizing wall tie of tower crane, it is necessary to have more careful verification in order to apply generally the results of this study.

• Applied Biological Chemistry
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• v.30 no.1
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• pp.65-70
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• 1987

In Girder to measure the pressure and weight decrease of drying sample during the vacuum drying process of food, sensing devices were designed and constructed with strain gauge. Microcomputer based vacuum drying system was made up of these devices interfaced to apple II microcomputer. The electrical output signal from vacuum sensor which constituted with Bourdon tube whereon strain gauge attached were digitalized and input to microcomputer through the MC 6821 interface I.C. chip. The relationship between read-out digital value (D) from microcomputer and readings of vacuum gauge (P, mmHg) was P=-146.136+3.620D'(r=0.9994) The pressure control of vacuum dryer was successfully conducted in the range of $400{\sim}600\;mmHg$ accuracy. The digitalized load cell output (D) could be correlated with the real weight (W, g) as W=-14,000+0.585D (r=0.9998) Drying curves of green red pepper under $64^{\circ}C$, $400{\sim}600\;mmHg$ was similar to those of red pepper and differently affected by the degree of vacuum pressure but was varied according to their shape (cut or whole). Moisture movement of green red pepper during the vacuum drying process was fitted to Page model. The empirical equations obtained were $M-M_e/M_o-M_e={\exp}\;(-0.0673{\theta}^{1.177})$ and $M-M_e/M_o-M_e={\exp}\;(-0.0655\;{\theta}^{1.477})$ for whole and cut green red pepper, respectively.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.351-360
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• 2009

This study is a series of experimental investigations of the buckling strengths of eccentrically compressed, cold-formed, stainless-steel, circular, hollow-section beam columns. The principal parameters that were used in this study were the slenderness ratios (Lk/r = 30, 50, 70) and the magnitude of eccentricity e(one way: 0, 25, 50, 75, and 100mm: the other way: 0, 12.5, 25, 37.5, and 50mm) on the asymmetrical end-moment of a double curvature. The objectives of the study were to obtain the maximum loads through an experiment and to compare the experimental behaviors with the analysis results. The ultimate buckling strength of the square section members were evaluated using a numerical method, in accordance with the bending moment-axial force(M-P) interaction curves. The behavior of each specimen was displayed in the form of the strength-displacement and moment-angle(M-$\theta$) relationship.