• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.233-236
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• 2004

The major objective of this paper is to clarify the effect of constitutive laws on bulk forming design based on the ideal flow theory. The latter theory is in general applicable for perfectly/plastic materials. However, its kinematics equations constitute a closed-form system, which are valid for any incompressible materials, therefore enabling us to extend design solutions based on the perfectly/plastic constitutive law to more realistic laws with rate sensitive hardening behavior. In the present paper, several constitutive laws commonly accepted for the modeling of cold and hot metal forming processes are considered and the effect of these laws on one particular plane-strain design is demonstrated. The closed form solution obtained describes a non-trivial nonsteady ideal process. The design solutions based on the ideal flow theory are not unique. To achieve the uniqueness, the criterion that the plastic work required to deform the initial shape of a given class of shapes into a prescribed final shape attains its minimum is adopted. Comparison with a non-ideal process is also made.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.29-29
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• 2010

Surface contamination and leakage current have caused operating problems. A flashover in a substation may result in destruction of an insulator or many others electrical equipment. Engineering plastics have good characteristic (light weight, good productivity and little of void) as compare with epoxy or porcelain insulators. Outdoor insulator must have resistance to contamination. However, it isn't suited to outdoor insulator because it is not hydrophobic. RTV(Room temperature vulcanizing) has a good property of hydrophobic and micro-filler. nano-filler have characteristics of obstructing exothermic reaction. In order to reduce the incidence of insulator flashover and damage, the silicon rubber contained with micro, nano-filler coating on surface of engineering plastics. In this paper, it compares tracking resistance, leakage current of the engineering plastic coated RTV with that of non-coated engineering plastic. And filled-composites performed much better than non-filled composites.

• Archives of Plastic Surgery
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• v.33 no.4
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• pp.399-406
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• 2006

Purpose: The authors accessed the anthropometric measurements of fourty non-cleft normal a three-month-old infant and using this obtained data as a basic guideline, authors applied the modified Noordhoff technique for the treatment of bilateral cleft lip. Methods: Over a period of 10 years, a total of 21 bilateral cleft lips were operated. 13 cases of complete and 8 cases of incomplete bilateral cleft lip and palate. In the complete type of bilateral cleft palate, elastic head cap and passive intraoral appliance were applied at 1 to 2 week of age for 2 months duration. The definitive cheiloplasty was performed at 3 months of age using the modified Noordhoff technique. Results: After a follow-up period ranging one to nine years, most patients presented with cosmetically and functionally satisfying results, with an exception of two cases where an undesired peaking effect of the vermilion and dimpling of the vermilion mucosa was encountered. Conclusion: Accessing the anthropometric measurements of fourty non-cleft normal three-month-old infant and using this obtained dara as a guideline, the modified Noordhoff technique can be applied to either complete or incomplete bilaterally cleft lip providing more naturally pleasing and cosmetically satisfying scars that lie in harmony with the philtral ridges, lip tubercle positioned just below the vermilion and a distinct white line and Cupid's bow.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1740-1747
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• 2000

Under repeated rolling, initial plastic deformation introduces residual stresses which render the steady cyclic state purely elastic. This is called the process of shakedown. Many studies have been done about the shakedown in semi-infinite half space using calculated Hertizian pressure. In this paper shakedown processes in a shaft are studied by finite element analyses of a two dimensional(plane strain) model with elastic-linear-kinematic-hardening-plastic material subjected to repeated, frictionless rolling contact. Symmetric and non-symmetric pressure distributions are obtained using a simplified model of the bearing-shaft assembly. The rolling contact is simulated by repeatedly translating both pressure distributions along the surface of the shaft. By the influence of the non-symmetric pressure, larger residual radial tensile stress is generated in the immediate subsurface layer, which may make a crack propagate and, the subsurface undergoes a zigzag plastic deformation during the shakedown process, which may lead to a crack initiation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.4
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• pp.19-30
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• 2002

The stability of slope using root-pile like to the reinforcements is affected by the interaction behavior mechanism of soil-reinforcements. Through the studying on the interaction in joint of its, therefore, the control roles can be find out in installed slope. In study, the stress level ratio based on the insert angle of installed reinforcements in soil used to numerical analysis, which was results from the duty direct shear test in Lab. The maximum shear strain variation on the reinforcements was observed at insert angle, which was approximately similar to the calculated angle based on the equation proposed by the Jewell. The elasto-plastic joint model on the contact area of soil-reinforcements was presumed, the reinforced soil assumed non-linear elastic model and the reinforcements supposed elastic model, respectively. The finite element analysis of assumed models was performed. The shear strain variation of non-reinforced state obtained by the FEM analysis including elasto-plastic joint elements were shown the rationality of general limit equilibrium analysis for the slope failure mode on driving zone and resistance zone, which based on the stress level step according to failure ratio. Through the variation of shear strain for the variation of inserting angle of reinforcements, the different mechanism on the bending and the shear resistance of reinforcements was shown fair possibility.

• Archives of Craniofacial Surgery
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• v.19 no.4
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• pp.287-290
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• 2018

Tumoral calcinosis is a condition characterized by deposition of calcium salts in the skin and subcutaneous tissue, commonly found around the joints. However, tumoral calcinosis of the auricle is extremely rare. We present the case of a 13-year-old boy with tumoral calcinosis of the helix of the ear auricle. A 13-year-old boy presented with a 10-year history of an enlarging mass on the left auricle. The mass was hard, non-tender, and non-compressible. The patient had no history of trauma. Complete surgical excision and pathological examination of the specimen was performed. The final diagnosis of the excised mass was tumoral calcinosis. After 9 months of follow-up, there were no signs of recurrence of the tumor and the patient was satisfied with the surgical results. Tumoral calcinosis of the auricle is extremely rare and may be misdiagnosed as other tumors. Pathological examination is essential for definitive diagnosis and complete surgical excision should be considered as the treatment of choice.

• Archives of Craniofacial Surgery
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• v.20 no.1
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• pp.66-70
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• 2019

Mucosa-associated lymphoid tissue (MALT) lymphoma is an uncommon form of non-Hodgkin lymphoma involving the mucosa-associated lymphoid tissue. Most commonly affected organ is the stomach. But, it could affect almost every organ in the whole body. If they have suspicious lesion, excision biopsy could be made. For staging, blood test including blood smear, abdomen and chest tomography or scan will be checked. Also, bone marrow test can be done if it is needed. The patient had visited the clinic for palpable mass on right lower eyelid. With excisional biopsy, it was diagnosed as lymphoid hyperplasia on pathologic test. But 2 years later, the patient came with recurrent symptom for our department with worry. At that time, we recommended excisional soft tissue biopsy under general anesthesia. Unfortunately, it was revealed MALT lymphoma on pathologic finding. It turned out to be stage 3 in Ann Arbor staging system without B symptoms. Hematologic consultation was made and she was treated with adjuvant chemotherapy for eight cycles to complete remission. We report a case of MALT lymphoma on subcutaneous tissue at right lower eyelid previously diagnosed as lymphoid hyperplasia.

• Structural Engineering and Mechanics
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• v.14 no.5
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• pp.611-624
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• 2002

In this paper, a complete solution is presented for dynamic plastic response of a rigid, perfectly plastic hinged-free beam, of which one end is simply supported or hinged and the other end free, subjected to a transverse strike by a travelling mass at an arbitrary location along its span. The governing differential equations are expressed in non-dimensional forms and solved numerically to obtain the instantaneous deflection of the beam and the plastic dissipated energy in the beam. The dynamic behavior for a hinged-free beam is more complicated than that of a free-free beam. It transpires that the mass ratio and impact position have significant influence on the final deformation. In the aspect of energy dissipation, unlike simply supported or clamped beams for which the plastic deformation consumes almost the total input energy, a considerable portion of the input energy would be transferred as rigid-body motion of hinged-free beam, and the energy dissipated in its plastic deformation is greatly reduced.

• Archives of Plastic Surgery
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• v.33 no.2
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• pp.249-251
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• 2006

Human cysticercosis is an infestation with C. cellulosae, the larval stage of the tapeworm T. solium. It prevails in regions of poverty and where personal hygiene is poor. They can lodge in almost any tissue, but cysticerci are most frequently found in brain, skeletal muscle, subcutaneous tissues. We experienced a 41-year old male with $5{\times}12cm$ sized movable non tender brownish hard mass at lateral abdominal wall. The laboratory study didn't show any specific symptoms except peripheral blood eosinophilia and positive parasite ELISA screen for cysticercosis. The ultrasonogram revealed multiple ill-defined mixed echoic inflamatory lesion. Excisied cyst showed multiple severe foul-odor gelatinous subcutaneous mass. Microscopic examination disclosed necrotic body with foreign body reaction, massive eosinophilia and dead parasitic organism, compatible with cysticercosis. There was no evidence of recurrence during 12 months follow-up.

• Structural Engineering and Mechanics
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• v.36 no.5
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• pp.575-598
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• 2010

The shape and size of the plastic zone around the crack tip are analyzed under pure mode I, pure mode II and mixed mode (I+II) loading for small scale yielding and for both plane stress and plane strain conditions. A new analytical formulation is presented to determine the radius of the plastic zone in a non-dimensional form. In particular, the effect of T-stress on the plastic zone around the crack tip is studied. The results of this investigation indicate that the stress field with a T-stress always yields a larger plastic zone than the field without a T-stress. It is found that under predominantly mode I loading, the effect of a negative T-stress on the size of the plastic zone is more dramatic than a positive T-stress. However, when mode II portion of loading is dominating the effect of both positive and negative T-stresses on the size of the plastic zone is almost equal. For validating the analytical results, several finite element analyses were performed. It is shown that the results obtained by the proposed analytical formulation are in very good agreements with those obtained from the finite element analyses.