• Biomedical Science Letters
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• v.26 no.3
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• pp.186-191
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• 2020

This study was designed to investigate the median nerve cross-sectional area of the upper extremity which is the main cause of CTS in the 20s and 30s. The median nerve cross-sectional area (MNC-area) of each part of the upper limb was measured in healthy 20s and 30s females and males without neurological diseases or other diseases. This MNC-area was compared with the hand, wrist, finger, and other body indexes. The research group was divided into 20s female and male groups, and the 30s were also divided into female and male groups. In the comparison between the ages, the hand, and wrist configurations in the 30s were significantly higher than those of the 20s. The mean median nerve cross-sectional area was significantly larger in the male group than in the female group in both 20s and 30s, and it was larger in both men and women than in the 20s. Hand and wrist configurations were also positively correlated with the median nerve cross-sectional area in both 20s and 30s. The median values of hand ratio and wrist ratio were 2.26 and 0.65, respectively. This median value of hand ratio was inversely correlated with the median nerve cross-sectional area. The median nerve cross-area of the 20s was 6.88~7.38 ㎟ in the male group and 5.69~6.99 ㎟ in the female group, respectively. The median nerve cross-area of the 30s was 6.32~8.89 ㎟ in the male group and 6.15~7.17 ㎟ in the female group, respectively. The mean median nerve cross-sectional area was positively correlated with body mass index in both groups. Most of the variables were higher in their 30s than in their 20s.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.187-193
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• 1999

As the slenderness ratio increases, it is necessary to examine the increased sectional area of member by means of increasing buckling strength because the sectional area of compressive member is designed in accordance with buckling. In this reason tn reinforce insufficient strength it don not have to reinforce the whole sectional area of member. Force of member can be increased in a way to restrict buckling mode by means of the partially increased sectional area of member. Therefore, in this study, we put emphasis on compressive members among many members that constitute space frame and try to get basic data about the reinforcement of space frame by means of investigating the bucking characteristic according to the size and length of partially increased sectional area of member.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.619-625
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• 2019

It is difficult to design because of the plug-holing phenomenon in which the amount of smoke discharged from the vertical vent is smaller than the designed amount of smoke. In this study, the effect of cross-sectional area ratio of tunnel and natural ventilation and heat release rate of fire source on plug-holing phenomenon occurring in natural ventilation system was experimentally analyzed. In the experiment model reduced to 1/20 size, the aspect ratio of the tunnel and the vertical vent was fixed, and the influence on the plug-holing phenomenon was confirmed by varying the sectional area ratio of the tunnel and the vertical vent. Experimental results show that the plug-holing phenomenon is caused by the comparison of the smoke boundary layer temperature with the temperature in the vertical vents, and the flow and temperature distribution characteristics under the vertical vents are changed as the cross-sectional area ratio of the tunnel and vertical vents increases. The plug-holing phenomenon is affected by the cross-sectional area ratio between the tunnel and the vertical ventilation. The greater the cross-sectional area ratio, the greater the probability of plug-holing.

• Geomechanics and Engineering
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• v.14 no.2
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• pp.175-185
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• 2018

Sand Compaction Piles (SCPs) are constructed by feeding and compacting sand into soft clay ground. Sand piles have been installed with irregular cross-sectional shapes, and mixtures of both sand and clay, which violate the design requirement of circular shape according to the replacement area ratio due to various factors, including side flow pressure. Therefore, design assumptions cannot be satisfied according to the conditions of the ground and construction and the replacement area ratio. Two case histories were collected, examined, and interpreted in order to study the effect of the shape of SCPs. The effects of the distortion of SCP shape and the mixture of sand and clay were studied with the results of large direct shear tests. The design internal friction angle was secured with the irregular cross-sectional sand piles regardless of the replacement area ratio. The design internal friction angle was secured regardless of mixed condition when the mixture of sand and clay was higher than the replacement area ratio of 65%. Therefore, systematic construction management is recommended with a replacement area ratio below 65%.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1454-1459
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• 2004

The major parameters governing the fluid dynamical and thermo-dynamical behavior in the large pipeline network system are friction loss and the pipeline length. But in local pipeline networks and relatively short distance pipeline system, secondary loss and the considerations of the moving states of the fluid machine are also important. One of the major element in local pressure control system is pressure regulator. It causes the variations of the physical properties in that pipeline system. When it is under working, the accurate analysis of the flow properties is so difficult. In this study, some numerical approaches to investigate the critical-flow-characteristics of the pressure regulator have been done according to the variations of the opening ratio or cross-sectional area and the detail examinations and considerations of the pressure regulator as a pipeline network elements have been carried. Finally the flow-flied distributions and critical-flow-characteristics have been presented in detail and the critical flow phenomena and the relation to the opening ratio or cross-sectional-area ratio have been studied.

• Structural Engineering and Mechanics
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• v.37 no.3
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• pp.309-320
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• 2011

As a new type of large-span space structure, suspendome is composited of the upper single-layer reticulated shell and the lower cable-strut system. It has better mechanical properties compared to single-layer reticulated shell, and the overall stiffness of suspendome structure increases greatly due to the prestress of cable. Consequently, it can cross a larger span reasonably, economically and grandly with high rigidity, good stability and simple construction. For a better assessment of the advantages of mechanical characteristic of suspendome quantitatively, the static behavior of Kiewitt6 suspendome was studied by using finite element method, and ADINA was the software application to implement the analysis. By studying a certain suspendome, the internal forces, deformation and support constrained forces of the structure were obtained in this paper. Furthermore, the influences of parameters including prestress, stay bar length, cross-sectional area and rise-to-span ratio were also discussed. The results show that the increase of prestress and vertical stay bar length can improve the stiffness of suspendome; Cross-sectional area has nearly no impact on the static behavior, and the rise-to-span ratio is the most sensitive parameter.

• Progress in Superconductivity and Cryogenics
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• v.2 no.2
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• pp.15-19
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• 2000

The stability of variable cross-sectional area HTS current lead is considered. The cross-sectional area is varied to have a constant safety factor which is defined as the ratio of operating current and critical current of superconductor. As the constant area HTS lead, the variable cross-sectional area HTS lead also has three steady states above the bifurcation point and only one steady state below the bifurcation point. The temperature profiles and current sharing ratios for each steady state are calculated. The heat dissipation into cryogenic system for super-conducting, intermediate, and upper states are compared. For Bi-2333 sheathed with silver-gold alloy 2m length of current lead, and the maximum temperature of upper state seems to be burn-out free below 5m length.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.6
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• pp.460-472
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• 2023

This study was conducted based on the case of an accident (excessive deformation) that occurred during the hydraulic test of a shipboard tank manufactured in accordance with the design regulations. Over-pressure phenomenon was noted as the main cause of accidents in the process of testing tanks without physical damage, which can be found in external factors such as cross-sectional difference between inlet pipe and air pipe and higher water filling rate than the recommended one. The main goal of this paper is to establish a safe water filling rate according to the range of sectional area ratio(SAR) reduced below the regulations for each test situation. The simulation was conducted in accordance with the hydraulic test procedure specified in the Ship Safety Act, and the main situation was divided into two types: filling the tank with water and increasing the water head to the test pressure. The structural safety evaluation of the pressure generated inside the tank and the effect on the structure during the test was reviewed according to the SAR range. Based on the results, guidelines for the optimal filling rate applicable according to SAR during the hydraulic test were presented for the shipboard tanks used in this study.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.9
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• pp.1139-1148
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• 1997

Compression waves propagating in a high-speed railway tunnel develops large pressure fluctuations on the train body or tunnel structures. The pressure fluctuations would cause an ear discomfort for the passengers and increase the aerodynamic resistance of trains. As a fundamental research to resolve the pressure wave phenomenon in the tunnel, experiments were carried out by using a shock tube with an open end. A blockage to model trains inside the tunnel was installed on the lower wall of shock tube, thus forming a sudden cross-sectional area reduction. The compression waves were obtained by the fast opening gate valve instead of a conventional diaphragm of shock tube and measured by the flush mounted pressure transducers with a high sensitivity. The experimental results were compared with the previous theoretical analyses. The results show that the ratio of the reflected to the incident compression wave at the sudden cross-sectional area reduction increases but the ratio of the passing to the incident compression wave decreases, as the incident compression wave becomes stronger. This experimental results are in good agreements with the previous theoretical ones. The maximum pressure gradient of the compression wave abruptly increases but the width of the wave front does not vary, as it passes over the sudden cross-sectional area reduction.

• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.117-127
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• 2007

In this study, we evaluate the strength of steel box beam-to-column connections subjected to axial loads in steel frame piers. The T-connection strength was reduced due to the column axial force in the two-story pier structure. To examine this phenomenon, non-linear FEM analysis was carried out and the analytical procedure was verified by comparing it with experimental results. To clarify the effect of the axial force and major design parameters in connection with strength, influence of panel zone width-thickness ratio, sectional area, and axial force was investigated using FEM analysis. Also, the theoretical strength equations were suggested by stress distribution of panel zone. The strength of the T-connection was compared with one of the one-story pier structure connections. As a result, the strength evaluation equations are proposed in consideration of the panel zone width-thickness ratio and sectional area ratio for the T-connections.