• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.407-412
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• 2014

A new apparatus for seawater desalination, based on the principle of gas hydrates, is suggested. The equipment continuously produces and pelletizes gas hydrates by a squeezing operation in a dual cylinder unit, which is able to extract pure hydrate pellets from the seawater-containing reactor. Desalination efficiency for each dissolved ion from seawater samples was tested by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and ion chromatography (IC) analysis. This study demonstrates that the suggested method and the stated apparatus may solve the difficulty of separating hydrate crystals from concentrated brine solutions, and therefore may be applied to improve the efficiency of existing desalination processes.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.3 s.116
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• pp.72-78
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• 2006

The extraction properties of the biological waste originated from the Tobacco industry were evaluated. The biological waste have been recycled and transformed into a valuable material, so called a reconstituted tobacco sheet(Recon) by the papermaking process. In this process, The mechanical extraction process, which divides the mixed raw material slurry into the soluble stock and the insoluble stock, could affect not only the quality of final Recon product but also the productivity of whole Recon making process. This study investigated the effects of the extraction process on the slurry properties in detail. In order to quantify the amounts of the solubles which resided in the insoluble fibers, the washing treatment of the stock before and after squeezing process was applied. The amounts of the residual solubles showed little changes according to each stage of the extraction process. The fractionation of the slurry showed the difference in the amount of soluble in the stock depending on the size of the biological waste. After the extraction process, the bigger size fiber portion contained about 19%(by weight) in soluble after pressing but the smaller size fiber portion 9% in soluble. The fractionation ratio of the stocks also was changed by the screw press process, which could demonstrate the physical effects of the mechanical extraction.

• Composites Research
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• v.12 no.1
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• pp.11-18
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• 1999

The compression molding is widely used in the automotive industry to produce products that are large, thin, lightweight and stiff. The molded product is formed by squeezing a fiber-reinforced plastic composites. During a molding process of fiber reinforced thermoplastic composites, control of filling patterns in mold, orientation and distribution of fibers are needed to predict the effects of molding parameters on the flow characteristics. It is the objective of this paper to develop an isothermal compression molding simulation that can handle both thin and thick charges and motion of the flow front, and can predict pressure distributions and accurate velocity gradients. The composites are treated as an incompressible Newtonian fluid. The effects of slip parameter $\alpha$ and extensional/shear viscosity ratio $\zeta$ on the mold filling parameters are also discussed.

• Korean System Dynamics Review
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• v.3 no.1
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• pp.5-42
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• 2002

The main purpose of this paper is analyzing long-term growth possibility of a telecommunication Company (Telco) H. First of all, to achieve this purpose, the precise understanding about causal relations among growth and decay factors of Telco H is required. Based upon the causal analysis, a basic computer simulation model is developed. Finally, several predictive examinations about growth possibility and pattern of the Telco H are conducted using three scenarios. From simulation results, the most important policy leverages are capabilities of market share sustenance, improvement of service quality and squeezing current network facility to elevate profitability and efficiency. Recently, telecommunication industry has become more and more competitive due to introduction of Internet and deregulation. Internet has brought about global competition as well as confusion between telecommunication and broadcasting industries. At the almost same time, deregulation is a universal tendency and a catalyst of unlimited competition. Telco H has been a dominant company in Korea for last century. However, the dominant position of Telco H has been threatened by the change of competition environment. The competitive environment has many elements and keeps changing dynamically. Therefore, System Dynamics simulation methodology is adopted to examine the problem.

• Childhood Kidney Diseases
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• v.22 no.2
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• pp.75-80
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• 2018

Nutcracker syndrome is a phenomenon that the left renal vein (LRV) is pressed between the superior mesenteric artery (SMA) and the aorta. Clinical characteristics include gross or microscopic hematuria, orthostatic proteinuria, abdominal pain, and back pain. It occurs due to LRV squeezing caused by narrowed aortomesenteric angle. SMA syndrome is a disease that the third part of the duodenum is prone to intestinal obstruction by narrowed angle between the SMA and the abdominal aorta. Clinical symptoms include postprandial abdominal distension, epigastric pain, nausea, and vomiting. SMA syndrome and nutcracker syndrome have common features that result from narrowed aortomesenteric angle. However, it is very rare for both syndromes to occur simultaneously, so the two syndromes are regarded as separate diseases. This is a report on a case of nutcracker syndrome with SMA syndrome in a child who presented gross hematuria, recurrent abdominal pain and vomiting. To our knowledge, nutcracker syndrome simultaneous with SMA syndrome has not been previously reported in pediatric patient, especially with an exhibition of gross hematuria. This case suggests that the simultaneous presence of SMA syndrome with the same pathogenesis needs to be considered when nutcracker syndrome is suspected in pediatric patients with hematuria.

• Journal of Korea Foundry Society
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• v.19 no.1
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• pp.47-53
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• 1999

Squeeze casting process has been used in the field of a commercial manufacturing method, in which metal is enforcedly solidified under pressure enough to prevent the cast defects such as either gas porosity or shrinkage defect. In this paper, to clarify the relationship between applied pressures and macro ${\cdot}$ microstructural behaviors in gravity and direct squeeze casts, specimens were cast by various squeezing pressures during solidification of 7000 series Al wrought alloy in the metal die designed specially. The applied pressures used in this study were 0, 25, 50, and 75 MPa. The microstructural morphologies of squeeze cast were more fine and dense with increasing the applied pressures, because of the greater solidification rate of billet resulting from the applied pressure. A normal segregation phenomenon of an increasing in amount of eutectics towards the center of the billet was observed for squeeze casts, whereas gravity cast showed an inverse segregation phenomenon of an increasing in amount of eutectics towards the edge in the billet. This change in segregation pattern which is normal or inverse is due to a higher radial temperature gradient and reduced time in the semi solid state for squeeze casting.

• Journal of Korea Foundry Society
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• v.20 no.4
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• pp.269-276
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• 2000

So far, the study on semi-solid process has been carried out to develop and research new advanced materials without some casting defects. In this study, A356 billets consisted of various dendritic shapes were prepared using electro-magnetic stirring process continuously. As-cast respectively has liquidus temperature of $625.6^{\circ}C$ and solidus temperature of $573.55^{\circ}C$ A356 slugs were reheated homogeneously at different temperatures of 580, 590 and $605^{\circ}C$, followed by squeezing in a mold insulated with applied pressures(0, 25, 50 and 70 MPa). In order to investigate on aging responce for casts, 50 MPa squeezed specimen among all specimens was prepared in aging treatments, which conditions are aging temperature of $160^{\circ}C$ and holding times of 0, 45, 90, 270, 360, 720, 1440 and 2880 min after solution treatment ($540^{\circ}C$ for 10 hr). SSM ingot with the output velocity of 150mm/min appeared more spheroidal shape and fine structure than that with the output velocity of 250 mm/min. According to increasing in reheating temperature, numbers of fatigue cycles, U.T.S and elongation increased at same time.

• Journal of Korea Foundry Society
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• v.24 no.6
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• pp.331-339
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• 2004

Melt-extrusion process, a metallic melt poured and solidified up to semisolid state in the container can be directly extruded through the die exit to form a product of bar shape without other intermediate processes. In this study, the fabrication characteristics of the process were evaluated with various process parameters, such as preheating temperature of extrusion dies, extrusion temperature and extrusion ratio. AI-Cu alloys were successfully extruded after squeezing out of liquid during melt-extrusion with smaller force compared to the solid extrusion. Soundly AI-Cu alloy bar was fabricated at the preheating temperature of $500{\sim}520^{\circ}C$. The range of extrusion temperature for soundly melt-extruded AI-Cu alloy bar was increased with increasing extrusion ratio. Mechanical properties of melt-extruded AI-Cu alloy bars were found change with Cu content of the melt-extruded bars due to the occurrence of segregation. The various extrusion temperature yielded equiaxed structure with a grains size about 200 ${\mu}m$.

• The Research Journal of the Costume Culture
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• v.10 no.5
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• pp.578-589
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• 2002

The purpose of this research was to analyze the residual water retention and to determine the number and species of microorganisms from the wet cotton fabrics in dehydration and drying process during washing. The drying rates of terrycloth and interlock knit under the rainy seasons were measured according to the dehydration and hanging methods, layers of fabric and pre-treatment agents. Microorganisms were isolated from the dried terrycloth by pure culture, and were identified by Biolog system. The results are as follow: The initial water retention of fabrics after dehydration decreased in the order of dripping>centrifuge>squeezing method, which affected the drying rate. The drying rates were faster by increasing surface area of fabrics. There was no significant difference in drying rate among the fabrics pre-treated with detergent, or fabric softener, or cationic surfactants such as Cetyltrimethylammonium bromide(CTAB) and Benzalkonium chloride(BC). Puedomonas aureginosa was found in the fabrics treated with a powder-type detergent. On the other side, there was no growth of microorganism in the fabrics treated with a liquid-type detergent (containing antibacterial agent), CTAB and BC.

• Geomechanics and Engineering
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• v.21 no.6
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• pp.551-564
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• 2020

High-stress and complex geological conditions impose great challenges to maintain excavation stability during deep underground mining. In this research, large anisotropic deformation and its management by support system at a deep underground mine in Western Australia were simulated through three-dimensional finite-difference model. The ubiquitous-joint model was used and calibrated in FLAC3D to reproduce the deformation and failure characteristics of the excavation based on the field monitoring results. After modeling verification, the roles of mining depth also the intercept angle between excavation axis and foliation orientation on the deformation and damage were studied. Based on the results, quantitative relationships between key factors and damage classifications were presented, which can be used as an engineering tool. Subsequently, the performance of support system installation sequences was simulated and compared at four different scenarios. The results show that, first surface support and then reinforcement installation can obtain a better controlling effect. Finally, the influence of bolt spacing and ring spacing were also discussed. The outcomes obtained in this research may play a meaningful reference for facing the challenges in thin-bedded or foliated ground conditions.