• Transactions of Materials Processing
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• v.11 no.4
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• pp.312-322
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• 2002

In this study, an innovative semi-solid die casting technology to replace heavier cast iron compressor parts with lightweight aluminum castings was proposed, and the application possibility for home-appliance component was investigated. The most important factors regarding the semi-solid die casting process are the reheating process of the raw materials to the semi-solid state, specifications of the forming machine, the optimal injection conditions and die design. Materials used in this study were A3S7 and hSn alloys fabricated by the electromagnetic stirring process. The optimal injection conditions for semi-solid die casting process were Presented with the reheating conditions of the semi-solid materials. To investigate the effect of plunger tip shape on the formability and mechanical properties in semi-solid die casting process for complicated shape part, two kinds of plunger tip shape with long and short plunger tip taper are proposed.

• Korean Journal of Materials Research
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• v.11 no.11
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• pp.991-996
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• 2001

This study is the manufacture of solid lubricant oilless bearing using sintered parts. PTFE was as organic solid lubricant and $MoS_2$ as inorganic solid lubricant, and its characteristics were studied. Thickness of lubricant was suited 25~$100\mu\textrm{m}$ for lubricant characteristics. Curring temperature of MoS_2$ film was 12$0^{\circ}C$, 2 hours and that of PTFE film was $260^{\circ}C$, 20 minutes. The solid weight and solid volume of $MoS_2$ film was 51.7% and 27.4%, and that of PTFE was 44.9% and 24.3%. Chemical resistant of PTFE solid lubricant oilless bearing was excellent as salt test was 520hours, and usable temperature range was $-200~+280 ^{\circ}C$. Conduction of electricity can be increase by addition of graphite or $$\alpha$- PbO_2$. The electric conductivity was 100~180$\Omega$.

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.79-82
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• 2012

The gas-solid reactor, such as rotary kiln, sintering bed, incinerator and CFB boiler, is the one of most widely used industrial reactors for contacting gases and solids. the gas-solid reactor are mainly used for drying, calcining and reducing solid materials. In the gas-solid reactor, heat is supplied to the outside of the wall or inside of the reactor. The heat transfer in gas-solid reactor encompasses all the modes of transport mechanisms, that is, conduction, convection and radiation. The chemical reactions occurring in the bed are driven by energy supplied by the heat transfer. This paper deal with the effect of heat transfer and chemical reaction in the gas-solid reactor.

• Journal of Environmental Health Sciences
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• v.29 no.4
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• pp.35-41
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• 2003

The objective of this study was investigate the generation rates, composition, proportion and calorific values each of material in the municipal solid wastes as well as the effect of incineration residual leachate on the environment in Yangsan sanitary landfill site. The results were as follows ; The annual average generation rate of municipal solid wastes in Yang-san is approximately 2.0 kg/cㆍd. The weight percent of combustible matters is on average 78∼87% and the lower heating values of municipal solid wastes is measured to be more than 2,151 kcal/kg after removing the briquette component. The food waste was major source of solid wastes in Yang-san city as 35% and its variation by seasons was negligible. Combustible part was larger than incombustible part of the domestic solid wastes in spring and summer. It is recommended that municipal solid wastes be treated by multiple methods such as the sanitary landfill, resources and recovery, composting and incineration.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.442-447
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• 2008

This paper presents a new approach to simulate fluid-solid interaction problems involving non-matching interfaces. The coupling between fluid and solid domains with dissimilar finite element meshes consisting of 4-node quadrilateral elements is achieved by using the interface element method (IEM). Conditions of compatibility between fluid and solid meshes are satisfied exactly by introducing the interface elements defined on interfacing regions. Importantly, a consistent transfer of loads through matching interface element meshes guarantees the present method to be an efficient approach of the solution strategy to fluid-solid interaction problems. An arbitrary Lagrangian-Eulerian (ALE) description is adopted for the fluid domain, while for the solid domain an updated Lagrangian formulation is considered to accommodate finite deformations of an elastic structure. The stabilized equal order velocity-pressure elements for incompressible flows are used in the motion of fluids. Fully coupled equations are solved simultaneously in a single computational domain. Numerical results are presented for fluid-solid interaction problems involving nonmatching interfaces to demonstrate the effectiveness of the methodology.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.960-962
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• 1999

Organically modifidied montmorillonites were synthesized from sodium montmorillonite and alkylammonium halids (stearyltrimethyl bromide and cetyltrimethyl bromide) by solid-solid reaction. The structure of the products by solid-solid reactions was similar to that observed in a conventional solution method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.4
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• pp.67-75
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• 1993

This study was carried out to investigate the applicability of Solid Contact Process for the improvement of Moving Media Complete Mixing Activated Sludge(MMCMAS) effluents. Laboratory MMCMAS Reactor and MMCMAS/Solid Contact were operated at the hydraulic loading of 122~340 L/m$^2$/d. The conclusions from this study were as follows ; The addition of Solid Contact tank to the MMCMAS reactor has increased the SCOD and SBOD removal efficiencies of 4 to 67% and 2 to 41%, respectively. In addition, the increments of nitrification rates were about 13 to 46%. It was also observed that the addition of Solid Contact tank has greatly increased the organic removal efficiencies at the higher hydraulic loading rates and also decrement of sludge production rates was 0.1 gVSS/gBODrem. It was therefore concluded that the addition of Solid Contact tank could have polished the effluent of MMCMAS at the higher hydraulic loading rates.

• Transactions of Materials Processing
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• v.6 no.4
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• pp.319-328
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• 1997

A flow stress involving strain, solid fraction, and breakage ratio, and solid fraction updating algorithm were proposed to depict the deformation behavior of materials at the semi-solid state. In case of isothermally simple upsetting of Sn-15%Pb alloy at the semi-solid state, by comparing the results of finite element analysis with the existing experimental results, the reliability of both the developed flow stress and updating algorithm were investigated. It was found that the verified program can effectively be used in the rigid-viscoplastic finite element analysis of the semi-solid forging processes.

• Journal of Pharmaceutical Investigation
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• v.19 no.2
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• pp.63-69
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• 1989

Dissolution characteristics of indomethacin (IMC) from hydrophobic polymer solid dispersions were investigated. IMC-polyvinyl chloride (PVC) and IMC-ethylcellulose (EC) solid dispersions were prepared. The dissolution patterns of pure IMC, IMC-PVC and IMC-EC solid dispersions prepared at various ratios (1:1, 1:3, 1:5, 1:9 and 1:19 w/w), and those of corresponding physical mixtures were compared. It was found that the dissolution rates of IMC from solid dispersions with PVC or EC decreased in the order of 1:1>1:3>1:5>1:9>1:19 as the drug to polymer ratios decreased. Also the dissolution rates of IMC from EC solid dispersions increased according to flow rate, but PVC solid dispersions were not affected significantly. After all, PVC and EC matrices could be applied in sustained-release preparation of IMC.

• Journal of the Korea Computer Graphics Society
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• v.3 no.2
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• pp.77-84
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• 1997

Solid modeling refers to techniques for unambiguous representations of three- dimensional objects. The most widely used techniques for solid modeling have been Constructive Solid Geometry (CSG) and Boundary Representation (BRep). Contemporary solid modeling systems typically support both representations, and bilateral conversions between CSG and BRep are essential. However, computing a CSG from a BRep is largely an open problem. This paper presents 3D geometric reasoning algorithms for converting a BRep into a special CSG, called Destructive Solid Geometry (DSG) whose Boolean operations are all subtractions. The major application area of BRep-to-DSG conversion is feature recognition, which is essential for integrating CAD and CAM.