• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.35-44
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• 2015

The resilient modulus model of EPS geofoam to be used for a flexible pavement design was developed. In this study, the model was applied to design the flexible pavement and to predict the magnitude of the deformation of EPS geofoam blocks as a subgrade in the flexible pavement structure by using the resilient modulus model of EPS geofoam (RMEG) program. The RMEG program presented how much the EPS geofoam subgrade settled over the designed duration and the AASHTO flexible pavement design equation with the resilient modulus of EPS geofoam noted that how long the flexible pavement endured under traffic loads with 70% reliability for the estimated duration with less than 5mm vertical deformation during 20.6 years without the significant pavement distress as a substitute material for the natural soils.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.41-48
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• 2011

Warm-Mix Asphalt(WMA) mixtures, which meet environmental protection and have high energy efficiency, are emerging as an alternative to hot-mix asphalt mixtures. The objective of this study is to evaluate WMA made with Aspha-min in the laboratory and to compare the design results accomplished by new Mechanistic-Empirical Pavement Design Guide(MEPDG) with control mixture. An asphalt mixture with a nominal maximum size of 12.5mm and PG64-28 binder was used. Resilient modulus tests for a control mixture and WMA with 0.3% and 0.5% of Aspha-min were conducted. The results obtained by MEPDG after inputting the test output into the design indicated that the predicted rut depth of WMA using Aspha-min was much lower than that of control mixture, and showed that WMA was more resistant to rutting than control mixture.

• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.195-205
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• 2001

This Paper describes a numerical method to evaluate the flexural strength of reinforced concrete members exposed to fire. An analytical method is developed for the moment-curvature relationship for the cross section which is subjected to high temperature. The method performs heat-transfer analysis for the cross sections and subsequently performs numerical analysis using the stress-strain relationships of concrete and reinforcing steel in various heat conditions. The results of the numerical studies are ; 1) the residual flexural strength exposing at high temperature is affected by the heating time, the depth of concrete cover and reinforcement ratio, 2) the residual flexural strength after exposed at high temperature is recovered of its original strength at minimum ratio of reinforcement, while members having half of maximum ratio and maximum ratio of reinforcement do not recover its original strength, 3) furthermore, the concrete may reach its maximum capacity before reinforcement yields in reinforced concrete members having maximum ratio of reinforcement.

• Journal of dental hygiene science
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• v.10 no.6
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• pp.459-464
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• 2010

The purpose of this study was to evaluate the physical properties of hydrophilic polyvinyl siloxane impression materials as change of material's storage temperatures. Working time, strain-in-compression, elastic recovery and consistency were tested according to ISO Standard NO. 1563. The results are as followed. 1. Working time decreased in cold storage. 2. Strain-in-compression was different in storage temperatures. Material's strain-in compression in cold temperatures were higher than in room temperature and in incubator. 3. A coefficient of elastic recovery varied by storage temperatures. The rate in cold temperature was the lowest and in incubator was the highest. 4. Consistency of impression substance different in storage temperatures. The extent in cold temperature is the highest and in incubator was the lowest. Statistical analysis(SPSS 14.0k, p>0.05) showed that storage temperature affect to material's physical properties. We recognized that the physical properties of polyvinyl siloxane impression materials were changed according to storage temperature.

• Composites Research
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• v.37 no.4
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• pp.301-309
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• 2024

Shape memory stents are used for treating vascular conditions like myocardial infarction, angina, and arteriosclerosis through their shape memory behavior. These stents are inserted into blood vessels to expand them, and their performance in terms of flexibility, elastic recovery, and deformation is influenced by their design. In this study, parameters affecting stent structural design were analyzed using Taguchi method, aiming to design structures that consider flexibility, elastic recovery, and deformation. Reflecting the actual conditions faced by stents, ISO standards were incorporated, and finite element analysis was conducted, considering shape memory composite material properties obtained from tensile tests, specifically hyperealstic properties. Ultimately, statistical significance of stent structural design was evaluated through ANOVA (Analysis of Variance), and an improved optimal design model compared to the existing one was proposed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.941-951
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• 1994

The resilient behavior of subbase materials, locally used in Korea. were evaluated in this study by performing laboratory MR tests. The variations of the MR value according to LVDT's location in experiments and moisture conditions, respectively, were evaluated. And, in order to determine the relevant MR characteristics of the prototype materials, laboratory model tests containing smaller particles than those of the prototype were conducted. Based on above results, the relationship of the MR and the bulk stress (${\theta}$) was suggested. The case using internal LVDT. gave much larger $M_R$ value than that using external LVDT, since the external LVDT somewhat overestimates the resilient strain. The measured $M_R$ in damp conditions ($S_r$=40%) was larger than that in wet conditions ($S_r$=70%) by about 10%. The relationship between the $M_R$ and the void ratio was linear according to particle size effect. The relationship of the $M_R$ and the bulk stress (${\theta}$) on subbase materials in damp conditions to be used in Korea could be recommended as $M_R=3960{\cdot}{\theta}^{0.60}$ psi.

• Composites Research
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• v.12 no.3
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• pp.45-54
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• 1999

In this paper, an experimental study on the buckling and postbuckling control of a laminated composite beam with eccentrically embedded SMA wire actuators is performed. For the purpose of enhancing the critical buckling load, buckling control is investigated through the use of reactive moment associated with the shape recovery force of SMA wire actuators. To improve the control authority for the buckling and postbuckling control of the SMA-composite beam, closed-loop control is used. The buckling and postbuckling control behaviours are presented and discussed qualitatively and quantitatively on loaddeflection plots considering the stacking sequence of the laminate, slenderness ratio of the beam and activation conditions of the SMA wire actuators. By maintaining the desired deflection shape with the proper reactive moment, buckling control can be extended to the postbuckling of the SMA-composite beam subjected to an external load.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.165-173
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• 1996

The dimensional accuracy of a final product is mainly affected by elastic die deformation during the forging and elastic recovery after the ejection in cold forging process. The investigations on elastic recovery are not so much as those of elastic die deformation. The elastic recovery can be determined by using the elastic-plalstic finite element analysis, but, this method has some limits such as poor conver- gence and long computational time, etc. In this paper, a theoretical analysis for predicting the elastic recovery of a final product in axi-symmetric forging process by using the rigid-plastic finite element method is presented. The rigid-plastic finite element analysis of a cold forward extrusion process involving loading, ejecting process is accomplished by rigid-plastic FE code, DEFORM. The effect of elastic die deformation on the final product dimenmsion is also considered. The calculated elastic recovery is compared is compared with the analysis result of elastic-plastic FE code. ABAQUS.

• Journal of Chest Surgery
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• v.34 no.1
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• pp.51-56
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• 2001

배경: 이상적인 판막의 개발이 있기 전에는 가능하다면 원래의 판막을 보수하는 것이 좋을 것이라는 생각이 당연하며 실제 임상연구가들은 기술적으로 가능하다면 판막재건술이 판막치환에 비해 대단히 좋은 임상경과를 취한다고 보고하고 있다. 그러나 판막 치환례에서 수술성적과 임상성적이 오히려 좋게 나타나는 경우 이유가 있을 것이고 그 근본원인은 심실의 기능에 따라 좌우되리라는 가설 하에 이를 규명하고자 하였다. 대상 및 방법: 순수승모판막폐쇄부전증으로 수술 받은 40명의 환자를 대상으로 하여 고전적 판막 치환술을 시행한 12례를 1군으로, 후엽을 보전한 18례를 2군으로 그리고 성형수술을 시행한 10례를 3군으로 나누어 수술전의 심에코 소견을 포함하여 입원시에 시행한 전신상태와 수술 후 4주 이내에 시행한 심에코도의 각종 지표를 시행하였다. 결과: 일반적인 환자의 상태변화로는 1군에 비해 2군, 3군에서는 더 나은 결과를 보였으나, 통계적인 차이는 발견할 수 없었다. 뉴욕 심장협회의 분류에 따라서는 수술전보다 많은 호전이 보였으나 세군간의 유의한 차이는 발견할 수 없었다. 심에코도에 따른 심기능을 비교한 바에 의하면 1군에서는 오히려 나빠졌으며 2군, 3군에서는 수술직후에는 술전에 비해 별 차이가 없으며 회복후에는 모든 지표에서 의미있는 호전을 발견할 수 있었으나, 구별분획에 있어 두 군간에는 수술전, 수술후, 회복후의 상호간의 통계적으로 의미 있는 차이는 발견되지 않았다. 결론: 심기능의 차이가 나므로 승모판막폐쇄부전증에 대한 수술로는 가능한한 판막 성형술이 좋고, 판막 성형술이 불가능한 변형이 많은 경우 판엽 일부를 보전이라도 하는 것이 좋다.

• The Korean Nurse
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• v.23 no.3 s.126
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• pp.68-76
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• 1984

본 환자를 간호하면서 절단으로 인해 신체적 고통을 받고 있는 존재로서, 생각과 정서, 욕구를 지닌 존재로서의 환자를 돕고자 시도해 보았다. 신체적인 적응을 돕기 위해서 근력강화와 관절가동역증진, 통증조절, 보조기 착용을 위한 단단의 관리, 잔여관절의 변형예방에 중점을 두었다. 심리적인 적응을 돕기 위해서 환자가 절단 수술과 수술 후 변화된 신체외모를 수용하는 과정을 증시했다. 끝으로 사회적인 면에서는 의미있는 사람들의 집단속에서 존재하는 인간으로서의 환자에게 관심을 두었다. 환자의 우측 슬관절 가동역은 완전히 회복된 상태는 아니지만 목발을 이용하여 걷거나 기타 일상생활을 하는데 불편함은 없으며 앞으로 계속적인 노력을 통해 회복될 수 있을 것이다. 그의 좌측 고관절 가동역은 정상유지되고 있으며 절단부위는 보조기 착용에 적합하게 형성되어 가고 있다. 비슷한 처지에 있는 이씨환자의 도움과 환자의 독립적인 생활태도는 환자가 자신의 불구에 적응하고 일상생활에 적응하는데 많은 도움이 되었다. 협조적이고 동정적인 환자들과 의료진의 도움으로 환자는 보호된 병원환경내에서 신체적 제한점을 주목하고 자신의 불구에 적응하면서 타인들과 원만한 관계를 유지해 왔다. 그는 앞으로 사회에 돌아가서 생활하게 될 것이다. 우리 사회는 아직도 그들에 대해 편견을 가지고 있으며 직업적 교육적 의료치료적 배려가 부족한 상태이다. 사회속에서의 적응은 병원에서의 적응보다 훨씬 더 어려울 것이며 때로는 그를 좌절하게 할 것이다. 그의 신체적 결함이 자기 자신만의 책임은 아니며 어느 누구나 사고에 희생될 가능성은 있다. 사회인들이 그들에게 관심있고 수용적인 태도를 지니고 그들의 정상 요구와 인간으로서 동등하게 살아갈 권리를 인정하고 받아들인다며 좀더 쉽게 자신의 슬픔을 극복할 수 있을 것이다.