• Journal of the Korean Society for Precision Engineering
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• v.30 no.7
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• pp.741-748
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• 2013

A conventional packing ring was designed with a large clearance to prevent damage due to the vibration of the rotor, which can lead to an increase in steam leakage. In this study, a flexible packing ring using winding springs was developed to prevent damage to the rotor teeth by minimizing vibration, while maintaining a smaller clearance than that of conventional rotor designs. Theoretical analysis and finite element analysis (FEA) were used to design the winding spring to satisfy the specified allowable stress limit and minimum load requirements. The shape of the winding spring was designed by applying curves to the center and end parts of a flat spring. Computational fluid dynamics (CFD) analysis was used to predict the leakage of the flexible packing ring. Flow rate measurement tests were performed to verify the leakage reduction efficiency and the reliability of the CFD analysis.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.57-62
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• 2017

Recently, the use of electronic control units in vehicle has increased. The ECUs are connected to in vehicle networks to process a large amount of information. In this paper, for an actuator that is interconnected to CAN and FlexRay, a FlexRay-CAN gateway is presented and a data packing algorithm with a bisection method of a FlexRay slot is proposed. And, a network based actuator control system and packing map is implemented. With the proposed packing method, contact force sensor data are transferred within the maximum allowed delay to ensure the stability. The proposed method is useful for control of distributed system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.12
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• pp.477-482
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• 2016

Airtight containers have been widely used in many industries and household. They need a packing for sealing between the inside and outside. Previous packing materials have some drawbacks like stench, stickiness, and difficulty of applying to automated manufacturing systems. So, a new packing material which is harmless and suitable for automation is needed. This study performed a hot plate welding process of thermoplastic elastomer (TPE) as the packing material. The hot plate welding process included a phase change process of solidification and melting. The porosity-enthalpy method was adopted in order to simulate phase change problems. The TPE showed non-Newtonian fluid characteristics during the melting process. Since properties of SEBS are not well-defined, we established TPE properties by observing the melting behavior of TPE. In order to find an optimized condition, a parametric study including packing thickness, shapes, hot plate temperature, and thermal resistance, was conducted.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.1004-1014
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• 2001

The fully automatic algorithm from initial finite element mesh generation to remeshing in two dimensional geometry is introduced using bubble packing method (BPM) for finite element analysis. BPM determines the node placement by force-balancing configuration of bubbles and the triangular meshes are made by Delaunay triangulation with advancing front concept. In BPM, we suggest two node-search algorithms and the adaptive/recursive bubble controls to search the optimal nodal position. To use the automatically generated mesh information in FEA, the new enhanced bandwidth minimization scheme with high efficiency in CPU time is developed. In the remeshing stage, the mesh refinement is incorporated by the control of bubble size using two parameters. And Superconvergent Patch Recovery (SPR) technique is used for error estimation. To verify the capability of this algorithm, we consider two elasticity problems, one is the bending problem of short cantilever beam and the tension problem of infinite plate with hole. The numerical results indicate that the algorithm by BPM is able to refine the mesh based on a posteriori error and control the mesh size easily by two parameters.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.59-65
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• 2019

In many industries, particle packing is adopted quite frequently. In the particle packing process, the Discrete Element Method (DEM) can analyze the multi-collision of particles efficiently. Two types of contact models are frequently used for the DEM. One is the linear spring model, which has the fastest calculation time, and the other is the Hertz-Mindlin model, which is the most frequently used contact model employing the DEM. Meanwhile, very tiny particles in the micrometer order are used in modern industries. In the micro length order, surface force is important to decreased particle size. To consider the effect of surface force in this study, we performed a simulation with the Hertz-Mindlin model and added the Johnson-Kendall-Roberts (JKR) theory depicting surface force with surface energy. In addition, three contact models were compared with several parameters. As a result, it was found that the JKR model has larger residual stress than the general contact models because of the pull-off force. We also validated that surface force can influence particle behavior if the particles are small.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.253-256
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• 2022

실사 영상 기반의 메타버스 환경을 구축하기 위한 다수의 카메라를 통한 영상 취득 및 부호화, 전송 기술이 활발히 연구되고 있고, 이를 위해 영상 압축 표준화 단체인 moving picture experts group (MPEG) 에서는 MPEG immersive video (MIV) 표준을 개발하였다. 하지만, 현재 널리 사용되는 가상 현실 영상을 스트리밍 가능한 장비의 연산 능력으로는 MIV 기반 몰입형 영상을 스트리밍 시 복호기 동기화 문제가 발생할 수 있다. 따라서 본 논문은 저사양 및 고사양 장비에서 적응적으로 복호기 개수를 조절 가능한 geometry packing 기법을 MIV 의 참조 소프트웨어인 test model for immersive video (TMIV)에서 구현한다. 제안하는 패킹 기법은 지오메트리 영상을 패킹하여 텍스쳐 영상과 같은 높이를 가지도록 한 후 각각 단일 서브픽쳐 (subpicture) 로 부호화한다. 이후 부호화된 서브픽쳐들에 적응적으로 비트스트림 병합이 적용되어 장비의 복호기 사양에 대응한다.

• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.23-28
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• 2007

This paper presents an experimental investigation on the sealing defects and cracks of O-rings and a valve packing of a gas valve for a LPG cylinder. O-ring in which stops a gas leakage of a liquefied petroleum gas is very important for a LPG valve safety. Valve packing is to open and close a gas flow port for supplying and charging a LPG fuel. The sealing performance of two sealing units ism related to the leak safety and long lift of a gas valve. The investigated results show that most of O-rings was failed due to a circumferential crack in which is caused by partial press bonding failure near the partition zone and an excess compression rate. Some of the O-ring failure was originated by an extrusion of an excessive leak pressure of a LP gas. Thus, this paper strongly recommends a tight quality control and a safety guarantee system of O-rings and valve packing to guarantee a leak safety and to extend a service lift of a gas valve. At the end, a warranty policy of the sealing units should be adopted for increasing a product quality and safety of a gas valve.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.3
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• pp.307-317
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• 2020

The barrier structure of the skin's epidermis is a key structure to prevent the loss of water inside the body and the invasion of foreign substances, and is composed of keratinocytes and intercellular lipids. At this time, the intercellular lipids of the skin barrier has the strongest structure when packed in an orthorhombic structure. However, it is damaged by various external causes and changes to a hexagonal structure. This change in physical structure can be analyzed non-invasively by analyzing the signal of the CH₂-CH₂ scissoring band of lipids using FT-IR. In this study, SDS was treated on porcine skin to construct a skin barrier damage model, and the degree of change in packing structure was quantified by analyzing FT-IR signals. We then judged whether the barrier of the damage model was recovered according to the treatment of the cosmetic formulation. From these results, an indirect method of measuring the water evaporation of the skin barrier to date can be supplemented. In addition, physical changes in the structure of the skin barrier can be utilized in a direct and efficient manner to identify the function and verify the formulation of various materials.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.323-330
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• 2023

The skin's barrier structure is formed through the differentiation process of epidermal keratinocytes. It consists of corneocytes that are composed of keratin proteins and lipids that fill the spaces between them. During this process, the lipids such as phospholipid that made up the membrane of the basal layer cells of the epidermis are decomposed and replaced with newly synthesized components like ceramide. In this study, the effect of ginsenoside Rg3 components on the packing of the intercellular lipid structure of the skin barrier and the barrier function was confirmed. To confirm this, Rg3 components were treated during the differentiation process of 3D epidermal cells. The FT-IR and TEWL analysis on 3D epidermis showed an enhancement in the orthorhombic lipid packing and an improvement in barrier function. Additionally, in HaCaT cells, an increase in the expression of EVOL1 and EVOL4, which synthesize long-chain lipids, was detected, along with a decrease in CERS6, which synthesizes short-chain ceramide, and an increase in ACER6, which decomposes ceramide using phytosphingosine. This suggests the possibility that Rg3 affects lipid synthesis during the epidermal differentiation process, resulting in changes in barrier function.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.715-720
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• 2001

The main reason for applying positive pressure variable clearance packing in fossil power plant is high efficiency and energy saving movement in the government. This study intends to analyze the turbine efficiency through the shaft packing improvement in thermal power plant and makes its comparison to that of the used packing.