• Journal of the Korean Institute of Gas
• /
• v.19 no.6
• /
• pp.105-109
• /
• 2015

In this paper is proposed for the oil return device developed to perform efficient emergency operation in the event the sea oil spill. Oil recovery apparatus for spilled oil on marine aims to quickly purged with high recovery. Oil recovery apparatus can prevent secondary pollution which may occur in the purification method using the adhesion agent and chemicals. Also it has excellent properties oil recovery. Adopted by the vapor explosion-proof mechanism to remove the risks that may occur during oil recovery operations.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.6
• /
• pp.604-608
• /
• 2015

In this paper, we study the characteristics of heat transfer for an insulated multi-core tube using glass wool as an insulator for the multi-core tube. By performing experiments and modeling, we examine the variations in the temperature characteristics of hydraulic oil inside the multi-core tube with atmosphere temperature, inlet temperature, and the flow rate of hydraulic oil for the insulated multi-core tube that we developed. When the minimum inlet flow rate of hydraulic oil employed within the scope of the research is 0.29 l/min, the temperature difference obtained in the experiments and numerical analysis was a maximum of $3^{\circ}C$. For a constant atmospheric temperature, as the inlet temperature of the hydraulic oil increases, the outlet temperature of the hydraulic oil will also increase, regardless of its inlet flow rate. Further, when the inlet flow rate of the hydraulic oil is more than 1.01 l/min, the effect of the atmospheric temperature on the temperature drop of the hydraulic oil is low.

• Journal for History of Mathematics
• /
• v.26 no.2_3
• /
• pp.131-148
• /
• 2013

Euler's formula provides the topological characteristics of geometrical objects including polyhedra, and so an important mathematical concept. Descriptions on Euler's formula had been in the textbooks according to the 3rd through 7th National Mathematics Curriculum. However, they are gone after that. In this study, we focus on Euler characteristic and Euler's formula as an educational material for educations for the gifted or after-school educations. We first look at the mathematical history and the applications of Euler's formula and national curriculums to search for its mathematical and educational meaning. We further make a suggestion for a learning environment which provides a better education relying on search activities, not just depending on memorization, illuminated from the education of Euler's formula.

• Economic and Environmental Geology
• /
• v.47 no.3
• /
• pp.247-254
• /
• 2014

The compressibility of fracture in naturally fractured reservoir is larger than the compressibility of matrix in rock, although the compressibility of a typical rock is very small. The effective compressibility including the fracture compressibility should be considered to predict oil recovery correctly. It is hard to quantify changes of fracture aperture and pore volume in reservoir without the effective compressibility. In this study, oil recovery is analyzed by commercial simulator concerning the fracture compressibility based on fracture properties. We found that the effective compressibility affects oil recovery with change of polymer flooding factors such as polymer molar weight, concentration and injection rate. The estimated cumulative oil production is smaller with the effective compressibility than without it. Also, bottomhole pressure decreases rapidly without considering effective fracture compressibility.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.5
• /
• pp.541-548
• /
• 2017

A theoretical study on gas-liquid two-phase flow flushing systemnitrogen gas to the oil used for existing flushing equipment was conducted on the basis of ISO code so as to improve performance of existing high-temperature oil flushing equipment used in ocean plant facility drying field. For study, we analyzed process simulation results mixed fluid mixing ratio, temperature, Reynolds number and liquid hold up affectcleaning performance after designing oil-nitrogen gas mixture flushing system process. As a result, as the volume flow rate of mixed fluid increases with the tube diameter the volume fraction of the gas phase constant, the liquid fraction difference value at the inlet and outlet of horizontal hydraulic piping increases. It was found that the phase distribution between oil and nitrogen gas bubbles varies depending on the position the pipe lengthdirection. This change in phase distribution is expected to have a significant impact on the clean performance of an oil-nitrogen gas mixture flushing system.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.1
• /
• pp.579-584
• /
• 2017

The damper oil seal of a high-speed railway vehicle is made from nitrile butadiene rubber (NBR) in order to prevent lubricant from leaking into the damper and to stop harmful contaminants from entering the external environment while in service. Oil leakage through the seal primarily occurs from fatigue failure of the damper. Cumulative damage of the seal occurs due to the contact force between the rod and the rubber during movement due to track irregularities and cants, among other factors. Thus, the design of the oil seal should minimize the maximum principal strain at weak points. In this study, the optimal cross section of the damper oil seal was found using the multi-island genetic algorithm method to improve the durability of the damper. The optimal shape of the oil seal was derived using process automation and design optimization software. Nonlinear material properties for finite element analysis (FEA) of the rubber were determined by Marlow's model. The nonlinear FEA confirmed that the maximum principal strain at the oil leakage point was decreased 24% between the initial design and the optimum design.

• Korean Journal of Construction Engineering and Management
• /
• v.8 no.1 s.35
• /
• pp.116-123
• /
• 2007

Recently orders of project in the field of oil & gas plant have been increased due to raising oil prices and consumptions. Domestic oil & gas companies are expanding into the Middle East area and all over the world. In the field of oil & gas plant, it is important to manage a technical control and a license that is occurred when developing the manufacturing processes and technologies. Because the oil & gas market has a lot of executions of the oversea construction, competitions between the advanced companies is more important. Therefore, we have to adopt systematic management style for achievements of the technical competitive power and the higher position. However, domestic oil & gas plant companies have not enough competitive powers of the license and the design phase. So, they are faced with difficulties of adopting the technology which is maximizing the effect of investments and scheduling a long-range plan. To achieve the technology management and the competitive power, this study proposes a long-range plan through the analysis of execution methods for technology management.

• Applied Chemistry for Engineering
• /
• v.24 no.2
• /
• pp.144-147
• /
• 2013

Sweating, which is the excretion of oil on the surface of a solid product containing several kinds of pigments in oil and is also solidified with wax, is a unique phenomenon often observed on the surface of cover make-up or lipstick. The cause of sweating is an imbalanced formula. Many studies have been conducted to decrease the symptoms of sweating in the field of cosmetics. Differential scanning calorimetry (DSC) is a thermo-analytical technique that measures the amount of heat required to increase the temperature of a sample as a function of temperature or time under certain conditions. DSC has been used to determine the thermal properties of oil/wax structures. This study investigates how the thermal characteristics correlate with the sweating symptoms. An oil/wax formulation with an optimal melting point was studied in an attempt to make a stable product by considering the thermal properties that represent minimal structural changes with temperature variation. In addition, the sweating of the oil/wax formulation was observed over a various temperature range. As a result, it was found that sweating was minimized when the structure remained static or little bit changed over a variety of temperatures.

• The Korean Journal of Applied Statistics
• /
• v.14 no.1
• /
• pp.39-57
• /
• 2001

Categorical data has sometimes misclassification errors. If this data will be analyzed, then estimated cell probabilities could be biased and the standard Pearson X2 tests may have inflated true type I error rates. On the other hand, if we regard wellclassified data with misclassified one, then we might spend lots of cost and time on adjustment of misclassification. It is a necessary and important step to ask whether categorical data is misclassified before analyzing data. In this paper, when data is misclassified at one of two variables for two-dimensional contingency table and marginal sums of a well-classified variable are fixed. We explore to partition marginal sums into each cells via the concepts of Bound and Collapse of Sebastiani and Ramoni (1997). The double sampling scheme (Tenenbein 1970) is used to obtain informations of misclassification. We propose test statistics in order to solve misclassification problems and examine behaviors of the statistics by simulation studies.

• Asian Journal of Turfgrass Science
• /
• v.26 no.1
• /
• pp.35-43
• /
• 2012

These studies were carried out to ascertain the effects of paraffin oil on prolongation of the green leaf color period in Zoysiagrass. Fifty-fold diluted 98% paraffin oil treatment obtained the lowest reduction rate of green color. In early October we sprayed 50-fold, 100-fold and 200-fold diluted 98% paraffin oil in a Zoysia japonica field in Hapcheon of Gyeongnam and Sangju of Gyeongbuk and in a Z. matrella field in Gumjung of Busan and Anseong of Gyeonggii. Leaf color maintained for 60 days after treatment in Zoysia japonica. Leaf color remained for 60 days after treatment in Anseong, Hapcheon and Sangju when treated in the mid-October. Chlorophyll content was higher in paraffin oil treatment areas than in control areas in early October. Weight reduction rate was lower in the paraffin oil treated than in untreated leaves of Zoysiagrass when sprayed in Gumjung and Anseong in early October and mid-October, respectively. The chlorophyll content in leaves of Z. japonica was increased by increasing the spray volume of paraffin oil in the same dose treated in Lexington, Kentucky, USA. Paraffin oil can be used to prolongate of Zoysiagrass leaf color.