• Steel and Composite Structures
• /
• v.52 no.5
• /
• pp.595-608
• /
• 2024

This study presents a static analysis of thin shallow cylindrical and spherical panels, as well as plates (which are a special case of shells), under Levy-type mixed boundary conditions and various loading conditions. The study utilizes the boundary discontinuous double Fourier series method, where displacements are expressed as trigonometric functions, to analyze the system of partial differential equations. The panels are subjected to a simply supported type 3 (SS3) boundary condition on two opposite edges, while the remaining two edges are subjected to clamped type 3 (C3) boundary conditions. The study presents comprehensive tabular and graphical results that demonstrate the effects of curvature on the deflections and moments of thin shallow shells made from symmetric and antisymmetric cross-ply laminated composites, as well as isotropic steel materials. The proposed model is validated through comparison with existing literature, and the convergence characteristics are demonstrated. The changing trends of displacements and moments are explained in detail by investigating the effect of various parameters, such as stacking lamination, material types, curvature, and loading conditions.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.909-911
• /
• 2002

Rises of current level at power applications, such as transformer, motor, power cable need for using stacked HTS tapes. In this paper, we measured rises of temperature and tap voltage in 4-stacked HTS tapes under over-current condition. We measured 4-stacked HTS tapes properties under over-current condition with a little temperature rise as well as a large temperature rise. Rises of temperature and tap voltage are measured by using E-type thermocouples and voltage taps, respectively. According to the results of measurement, rises of tap voltage under over-current condition with a large temperature rises depends on rises of temperature.

• 보존과학연구
• /
• s.25
• /
• pp.133-150
• /
• 2004

Once the object has been excavated at underwater condition, it should be subjected to condition that may cause its deterioration. Therefore, it is important that the object immediately keeps stable environment. It means that the object was excavated at underwater and it exposed the deterioration condition, as soon as possible it was not dried on surface, especially metallic and organic material. Iron objects is particularly notorious for rapid disintegration that it kept wet or stored in a stable environment. Ceramics, glass and stone were handled carefully that it prevented physical damage by mishandling. Organic materials of wood, leather, rope, bone must not be allowed to dry out because the creaking, shrinking and warping are well known disintegration. Therefore objects is basis of keeping stable condition in on-site and then it will have to pass through a detailed conservation process in the laboratory.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.91-92
• /
• 2002

Most studies of elsatohydrodynamic lubrication are oriented only to the measurement of film thickness itself with optical interferometer. In order to exactly investigate the characteristics of a certain lubricant under the condition of additives. especially for traction performance. it is also important to get the information of traction force as well. In this work. we developed the device for measuring friction force of EHL contact condition, which can trace the film thickness over the contact area with optical interferometer. To verify the validity of the measuring system, the friction force and film thickness under EHL condition are measured with the variation of additive ratios of viscosity Index improvers.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.6
• /
• pp.1035-1046
• /
• 2002

Time Delay Control(TDC) is a robust nonlinear control scheme using Time Delay Estimation(TDE) and also has a simple structure. To apply TDC to a real system, we must design Time Delay Controller to guarantee stability. The earlier research stated sufficient stability condition of TDC for general plants. In that research, it was assumed that time delay is infinitely small. But, it is impossible to implement infinitely small time delay in a real system. So, in this research we propose a new sufficient stability condition of TDC for general plants with finite time delay. And the simulation results indicate that the previous sufficient stability condition does not work even for small time delay, while our proposed condition works well.

• Journal of Veterinary Clinics
• /
• v.16 no.1
• /
• pp.8-12
• /
• 1999

The erythrocyte sedimentation rate (ESR) test could be applied well in clinic of men, horses or dogs. But the ESR test was not applied to clinic ruminants except for buffaloes since it was too low measure. To overcome this problem angled tube method was developed. This method was found to be useful for making diagnosis and prognosis. The results were summarized as follows. 1. In the early pregnancy condition, corrected ESR did not changed when compared with normal valures. 2. In the middle pregnancy condition, corrected ESR was increased when compeared with normal valures. 3. In the latter pregnancy condition, corrected ESR was increased when compeared with normal valures. 4. After parturition condition, corrected ESR did not changed when compeared with normal valures.

• Journal of the Korean Society of Safety
• /
• v.7 no.4
• /
• pp.23-32
• /
• 1992

Surface treatment and chemiluminescence characteristics of the polymer film. It was studied that the Intensities and rates of treatments are in proportional to condition of the treatment, considering the results of study on treatments to polymer film with discharge and ultraviolet irradiation through the methods such as surface resistance, contact angle, dyeing method, solace ten-sion and so on. It was also studied that the said has a nice correlation with the concerned result studied by chemiluminescence. Since the chemiluminescence will enable the Investigators to grasp a eertain condition caused by quitely slight deterioration with high sensitivity, it can be also used as a way for getting an information regarding the decision for degradation-condition and life-estimating of insulation material basically related to some security matters as well as surface condition of treatments through the above method.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.11a
• /
• pp.803-808
• /
• 2001

Mathematical basis of interpretation of data from nondestructive evaluation (NDE) methods in bridge inspection is presented. In bridge inspection with NDE methods, NDE data are not assessments. NDE data must be interpreted as condition of element. Interpretation is then assessment. Correct assessments of conditions of bridge elements depend on the accuracy and variability in test data as well as on the uncertainty of correlations between attributes (what is measured) and conditions (what is sought in the inspection). Inaccuracy and variability in test data defines the qualify or NDE test. The qualify or test itself is important, but in view of condition assessment, the significance of uncertainty in correlations of attributes and conditions must be combined. NDE methods that are accurate in their measurements may still be found to be poor methods if attributes are uncertain indicators of condition of bridge elements. This paper reports mathematical presentation of inaccuracy and variability in test data and of uncertainty in correlation of attributes to element conditions with three examples of NDE methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.453-456
• /
• 2007

The purpose of this study is to explain the importance of Vibration Monitoring Device by introducing an example of Predictive Maintenance System using Condition Monitoring System of Hydro-turbine generator. Confirming vibration of generation equipment is commissioning procedure during equipment completion for checking guaranteed items. Data from Generator output range are used to determine output band to continue the performance of equipment. The Vibration Monitoring System is not absolute method of maintenance, but if it is used well with expert, it will be visible, data-analyzed, scientific maintenance more than others. And also, Condition Monitoring System is very important for remote controlled small hydro-power plant although most of it is installed in Large hydro-power plant.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.43 no.4
• /
• pp.67-75
• /
• 2011

Sulfuric acid hydrolysis is a typical approach for producing cellulose nanocrystals. The method has been widely used, but it has a disadvantage of low yield of cellulose nanocrystals compared to mechanical method. To expand the application of cellulose nanocrystals in practical, we should be able to produce them with higher yield and the controlled properties. In this study, therefore, we intended to investigate the effect of sulfuric acid hydrolysis condition on the characteristics of the prepared cellulose nanocrystals. The concentration of sulfuric acid, temperature and hydrolysis time were varied, and the yield as well as diverse properties including the morphology, size and zeta potential were examined. We could obtain cellulose nanocrystals up to 70% of yield and found that the properties were dependent on the reaction condition. It would be helpful to select an appropriate condition for producing cellulose nanocrystals.