• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.308-311
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• 2004

Nowadays, plastic industry has needed to produce parts that require high precision and quality. To make a high precision and quality part, before injection molding, plastic material is investigated about their properties such as shrinkage, warpage, etc. In this study, experiments were conducted with PA6(polyamid) to figure out shrinkage behavior according to three type aspect ratio of samples. The injection speed that affects on shear rate, molecular orientation within plastic part was determined as main variable of experiment. As a result of experimental study, part shrinkage had a tendency to be decreased by increasing injection speed and aspect ratio of samples.

• Structural Engineering and Mechanics
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• v.35 no.6
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• pp.699-715
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• 2010

This paper investigates the structural responses of axially restrained steel beams under fire conditions by a nonlinear finite element method. The axial restraint is represented by a linear elastic spring. Different parameters which include beam slenderness ratio, external load level and axial restraint ratio are investigated. The process of forming a mid-span plastic hinge at the mid-span under a rising temperature is studied. In line with forming a fully plastic hinge at mid-span, the response of a restrained beam under rising temperature can be divided into three stages, viz. no plastic hinge, hinge forming and rotating, and catenary action stage. During catenary action stage, the axial restraint pulls the heated beam and prevents it from failing. This study introduces definitions of beam limiting temperature $T_{lim}$, catenary temperature $T_{ctn}$ and warning time $t_{wn}$. Influences of slenderness ratio, load level and axial restraint ratio on $T_{lim}$, $T_{ctn}$ and $t_{wn}$ are examined.

• Structural Engineering and Mechanics
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• v.26 no.5
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• pp.483-498
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• 2007

In case of considering the shear effect, the complete solutions are obtained for dynamic plastic response of a rigid, perfectly plastic hinged-free beam, of which one end is hinged and the other end free, subjected to a transverse strike by a travelling rigid mass at an arbitrary location along its span. Special attention is paid to new deformation mechanisms due to shear sliding on both sides of the rigid mass and the plastic energy dissipation. The dimensionless numerical results demonstrate that three parameters, i.e., mass ratio, impact position of mass, as well as the non-dimensional fully plastic shear force, have significant influence on the partitioning of dissipated energy and failure mode of the hingedfree beam. The shear effect can never be negligible when the mass ratio is comparatively small and the impact location of mass is close to the hinged end.

• Journal of The Korea Institute of Healthcare Architecture
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• v.7 no.1
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• pp.33-44
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• 2001

This study is about the Spatial Composition and Area Calculation in Plastic Surgical Clinics. 1. The space of the plastic surgical clinics are divided into 4 sections; exam, exam support, the staffs, and waiting and reception area. 2. The average G/N ratio of width was 1.46. The Plastic surgical clinics which had great deviation in the ratio showed these characteristics; first, when they were planned at first, the operation rooms were not assigned enough space; second. space for supporting exam and the activities of staffs was given too little consideration in their first drafts. 3. The average size of operation rooms was $21.76m^2$. The most desirable size was found to be $26.4m^2$ when we put the number of staffs, the movement area of stretcher, and the movement lines of operation room into consideration.

• Transactions of Materials Processing
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• v.12 no.5
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• pp.504-512
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• 2003

The plastic strain ratios(R-values) of low carbon steel sheets were determined by the automatic strain measurement method using two extensometers, the indirect photo method for the same tensile specimen during tensile test and the indirect method for the specimen after tensile test. The experimental results showed that the measured plastic strain ratios from the automatic strain measurement method using two extensometers coincided with those from the indirect photo method and the indirect method for all tensile specimens. In addition, the strain dependence of plastic strain ratios could be continuously recorded and the anisotropy of the strength coefficient, K, and strain hardening exponent, n, could be automatically calculated in three directions by computer through the use of two extensometers. The experimental results showed that the strain dependence of R-value was related to the anisotropy of strain hardening exponent in low carbon steel sheets.

• Archives of Plastic Surgery
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• v.33 no.2
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• pp.168-174
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• 2006

For over two thousand years, many artists and scientists have tried to understand or quantify the form of the perfect, ideal, or the most beautiful face both in art and in vivo(life). However, this mathematical relationship has been consistently and repeatedly reported to be present in beautiful things. This particular relationship is referred to as the golden ratio. It is a mathematical ratio of 1.618 : 1 that seems to appear recurrently in beautiful things in nature as well as in other things that are seen as beautiful. Dr. Marquardt made the facial golden mask that contains and includes all of the 1-dimensional and 2-dimensional geometric golden element formed from the golden ratio. The purpose of this study is to evaluate the usefulness of the golden facial mask. In our cases(n=40), the authors applied the facial golden mask to the preoperative and postoperative photographs, and scored each photograph. Compared with the average scores of the facial mask applied photographs and none applied photographs using non-parametric test, statistical significance was not checked (p > 0.05). It means that the facial golden mask can be used for facial analysis. The facial golden mask is easy to apply, cheap and relatively objective. So, the authors introduce the one of useful facial analyses.

• Earthquakes and Structures
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• v.11 no.5
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• pp.823-840
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• 2016

The plastic hinge lengths of beams and columns are a critical demand parameter in the nonlinear analysis of structures using the finite element method. The numerical model of a plastic hinge plays an important role in evaluating the response and damage of a structure to earthquakes or other loads causing the formation of plastic hinges. Previous research demonstrates that the plastic hinge length of reinforced concrete (RC) columns is closely related to section size, reinforcement ratio, reinforcement strength, concrete strength, axial compression ratio, and so on. However, because of the limitations of testing facilities, there is a lack of experimental data on columns with large section sizes and high axial compression ratios. In this work, we conducted a series of quasi-static tests for columns with large section sizes (up to 700 mm) and high axial compression ratios (up to 0.6) to explore the propagation of plastic hinge length during the whole loading process. The experimental results show that besides these parameters mentioned in previous work, the plastic hinge of RC columns is also affected by loading amplitude and size effect. Therefore, an approach toward considering the effect of these two parameters is discussed in this work.

• Resources Recycling
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• v.9 no.6
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• pp.23-30
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• 2000

Since most of the waste plastics are incinerated and landfilled for the plastic treatment, the environmental friendly processes must be introduced. The plastic utilization of plastic to the blast furnace as a substitutional fuel was developed as a useful recycling method of waste plastics, and commercialized in several ironmaking company in Europe and Japan. Present study was carried out to understand the effect of plastic injection on blast furnace process continuously by using the foundry blast furnace in POSCO. The coke replacement ratio turned out to be 0.98 with the waste plastic injection up to 13.8 kg/thm of injection rate, and there were no significant effect of the kinds of injection plastics on the replacement ratio in this test operation. The permeability in the furnace became worse and the heat load in the lower part of blast furnace was increased with increasing the injection rate of waste plastics. As the rate of plastic injection were increased, the top gas utilization and shaft efficiency were also decreased from the Rist diagram analysis.

• Earthquakes and Structures
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• v.5 no.4
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• pp.461-475
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• 2013

A new experimental system of base-isolated structures is proposed. There are two kinds of dampers usually used in the base-isolated buildings, one is a viscous-type damper and the other is an elastic-plastic hysteretic-type damper. The base-isolated structure with a viscous damper and that with an elastic-plastic hysteretic damper are compared in this paper. The viscous damper is modeled by a mini piston and the elastic-plastic hysteretic damper is modeled by a low yield-point steel. The capacity of both dampers is determined so that the dissipated energies are equivalent at a specified deformation. When the capacity of both dampers is determined according to this criterion, it is shown that the response of the base-isolated structure with the elastic-plastic hysteretic damper is larger than that with the viscous damper. This characteristic is demonstrated through the comparison of the bound of the aspect ratio. It is shown that the bound of aspect ratio for the base-isolated structure with the elastic-plastic hysteretic damper is generally smaller than that with the viscous damper. When the base-isolated structure is subjected to long-duration input, the mechanical property of the elastic-plastic hysteretic damper deteriorates and the response of the base-isolated structure including that damper becomes larger than that with the viscous damper. The effect of this change of material properties on the response of the base-isolated structure is also investigated.

• Archives of Plastic Surgery
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• v.34 no.1
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• pp.44-51
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• 2007

Purpose: Blow-out fracture is one of the most common fractures in facial trauma. It is diagnosed by Computed Tomography(CT) scan, which is considered as the most effective diagnostic tool. Since, the Picture Archiving Communication System(PACS) has been provided recently to many hospitals, doctors are more familiar with imaging software of PACS. Because this software has many useful measuring tools, doctors can measure orbital structure easily and make a plan for treatment with its data. Therefore, authors intended to analyze the data of orbital structure measured with PACS imaging software and evaluate its usefulness. Methods: The charts and CT images of 100 patients, which were 50 patients with medial wall fracture and 50 patients with floor fracture, were reviewed. Patients were selected by pre-determined criteria and their CT images were measured with image software of PACS. 'Extraocular muscle thickness', 'Defect ratio'(ratio of defect area to normal area) and 'Globe position index' were measured and analyzed statistically. Results: The thickness of inferior rectus muscle and medial rectus muscle was simultaneously increased in acute-stage of blow-out fracture. The medial rectus muscle was more thickened in medial wall fracture and inferior rectus was more thickened in floor fracture, respectively. In acute blow-out fracture, globe position is exophthalmic rather than enophthalmic. Especially in floor fracture, numerical value summed up thickness of all extraocular muscle is correlated to the defect ratio and globe position index. Conclusion: Clinicians can decide globe position or presume defect ratio in inferior wall fracture by measurement of CT image in acute blow-out fracture using PACS.