• 한국지반공학회논문집
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• 제24권12호
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• pp.13-22
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• 2008

지반조건과 말뚝의 테이퍼각도가 태야퍼말뚝의 지지력에 미치는 영향을 조사하기 위해서 원통형말뚝과 테이퍼각도가 다른 두 개의 메이퍼딸뚝을 이용해서 모형말뚝재하시험을 수행하였다. 시험결과에 띠르면 지반의 평균응력과 상대밀도가 커지면 테이퍼말뚝의 단위 선단지지력은 증가하였고, 말뚝의 테이퍼각도가 커집에 따라 느슨한 지반에서는 단위 선단지지력은 증가하였으나 조밀한 지반에서는 단위 선단지지력이 반대로 감소하였다. 그리고 테이퍼말뚝의 단위 주면마찰력은 지반의 수평 및 연직응력과 상대밀도, 말뚝의 테이퍼각도가 커짐에 따라 증가하는 것으로 나타났다. 한편, 모형말뚝재하시험의 결과에 근거해서 형상계수를 표함한 테이퍼말뚝의 지지력 산정식을 제안하였고, 이 제안식에서는 지반조건과 테이퍼각도가 말뚝의 지지력에 미치는 영향이 고려되였다. 제안한 지지력 산정식에 대한 정확도를 검증하기 위해서 점토질 모래지반에 설치된 중간규모의 원통형말뚝과 테이퍼말뚝에 대한 현장재하시험이 실시되었고, 이때 측정된 지지력이 제안식에서 얻은 예측치와 비교되었다. 그 결과 제안된 지지력 산정식은 테이퍼말뚝의 지지력을 비교적 정확하게 예측하는 것으로 나타났다.

• 대한물리치료과학회지
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• 제15권2호
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• pp.41-51
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• 2008

Background: The purpose of this study is to determine how the cognitive state of the elderly influences the activities of daily living(ADL) in order to increase their achievement capacity and their ability to exercise this capacity in daily life. The MMSE-K(Mini-Mental State Examination-Korean) was used to evaluate the daily activities and cognitive state of a group of subjects more than 65 years of age. The goal was to understand (1) How their achievement level in their daily activities changes according to the increase and decrease of their cognition points by analyzing and comparing their achievement points in the mental state examination, and (2) What variables influence that daily achievement level. Methods: The survey was conducted by a group of students from AnSan College who were trained for this method of data collection. The group surveyed 224 senior citizens older than 65 to determine their ADL performance. The subjects were selected from Silver Care Centers in the Gyounggi Province area including centers in Suwon, Anyang, Kwachun, and Sanbon City. The subjects were given enough information to fully understand the purpose of the study and the method by which it would be conducted. The survey method was a direct interview: which involved an interviewer reading the questionnaire to the subject and recording the answer. Result: The following results were calculated using SPSS WIN ver. 13.0: In the lower score of the MMSE-K regarding ADL performance (K-MBI) for activities such as individual hygiene, bathing activity, food activity, toilet management, going up stairs, getting dressed ad undressed, controlling stools and urination, walking, and chair/bed movement, most of the subjects responded that they could not perform these activities by themselves (p<.01). In the higher scores for the same activities, most response that they could perform the tasks by themselves (p<.01). In the results of the multiple regression analysis, there influence of the variables for ADL performance (K-MBI) and MMSE-K score was higher for females than males. Conclusion: This study evaluated the cognitive state of the elderly using the MMSE-K, which is the most convenient method, and examined how the cognitive state influences the achievement capacity of the daily lives with other variables. In conclusion, the higher the score on the MMSE-K, the more independent the elders are in the activities of daily living, especially among women more than men.

• 한국구조물진단유지관리공학회 논문집
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• 제19권1호
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• pp.13-22
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• 2015

본 연구에서는 기존 강도증진형 내진보강법의 단점을 보완 개선할 수 있는 새로운 개념의 내진보강법인 RCSF (Reinforced Concrete Steel Frame) 외부접합형 내진보강공법을 제안하였다. RCSF 보강법은 거주자가 거주가 가능하면서 내진보강 공사를 실시할 수가 있으며, 접합부 시공성이 탁월하며, 특히 필요 내진보강량 산정이 간편한 전형적인 강도증진형으로 전단파괴가 지배적인 비내진상세를 가지는 국내 중 저층 철근콘크리트 건물에는 내력확보가 용이한 내진보강공법이다. 본 연구에서 제안한 RCSF 외부접합형 공법의 유용성을 검증 할 목적으로 기존 중 저층 철근콘크리트 학교건물의 골조를 대상으로 유사동적실험을 실시하여 검증함과 동시에 내진보강효과를 검토하였다. 그 결과, 국내에서 발생 가능한 최대 지진규모 (300gal)에서 비보강 골조는 붕괴를 하였지만, RCSF 외부접합형 내진보강법으로 보강한 골조는 경미한 지진피해가 예상되었으며, 대규모 지진 (400, 500gal)을 상정한 경우에도 소규모 이하의 지진피해가 예상되어 본 연구에서 개발한 RCSF 내진보강법의 유효성이 검증되었다고 사료된다.

• 콘크리트학회논문집
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• 제27권2호
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• pp.147-155
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• 2015

본 연구에서는 기존 강도증진형 내진보강법의 단점을 보완 개선할 수 있는 새로운 개념의 내진보강법인 SRCF (Steel Reinforced Concrete Frame) 외부접합형 내진보강법을 제안하였다. SRCF 보강법은 거주자가 거주가 가능하면서 내진보강 공사를 실시할 수가 있으며, 접합부 시공성이 탁월하며, 특히 필요 내진보강량 산정이 간편한 전형적인 강도증진형으로 전단파괴가 지배적인 비내진상세를 가지는 국내 중 저층 철근콘크리트 건물에는 내력확보가 용이한 내진보강공법이다. 본 연구에서 제안한 SRCF 외부접합형 공법의 유용성을 검증 할 목적으로 기존 중 저층 철근콘크리트 학교건물의 골조를 대상으로 유사동적실험을 실시하여 내진보강효과를 검토하였다. 그 결과, 국내에서 발생 가능한 최대 지진규모(300gal)에서 비보강 골조는 붕괴를 하였지만, SRCF 외부접합형 내진보강법으로 보강한 골조는 경미한 지진피해가 예상되었으며, 대규모 지진(400, 500gal)을 상정한 경우에도 소규모 이하의 지진피해가 예상되어 본 연구에서 개발한 SRCF 내진보강법의 유효성이 검증되었다고 사료된다.

• 한국연초학회지
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• 제21권1호
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• pp.10-16
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• 1999

Leaves harvested were separated with visual characters into 2 classes such as immature and mature leaves. In the curing process, the prolonged yellowing treatment during yellowing stage was automatically controlled at the different stalk position, and condition of curing process after this period was all the same with conventional ones. In case of prolonged yellowing in immature leaves, increase of price per kg reached to 8 % compared with those of conventional ones. In physical properties, filling capacity and shatter index was decreased with the degree of maturity, and it was equal level in filling capacity of immature leaves between curing method, while shatter index was decreased in prolonged yellowing treatment than that of conventional ones. There was no difference in chemical components between immature leaves of prolonged yellowing and conventional ones. As to the prolonged yellowing of immature leaves, there was decreased in citric and malic acid contents of the nonvolatile organic acids, and it was equal level in all higher fatty acids content of leaves cured by prolonged yellowing treatment compared with in that of conventional curing method. The contents of key compounds such as solanone, damascenone, damascone in the essential oil were lower in prolonged yellowing of immature leaves than those of mature leaves cured by conventional ones.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.73-74
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• 2010

콘크리트 보의 휨 보강을 위한 FRP 플레이트가 콘크리트 하면에 직접 부착될 경우 콘크리트-FRP 부착경계면에서 대부분 콘크리트 박리파괴에 의한 최종파괴가 주로 발생된다. 본 연구에서는 이들 콘크리트 박리에 의한 취성파괴를 지연시켜 부착 보강재의 수명을 보다 더 연장시키기 위하여 콘크리트와 보강재 접착경계면 사이에 얇은 두께의 중간 삽입재(알루미늄, 티타늄)를 앵커와 에폭시로 부착, 기존의 FRP 플레이트 보강방법 보다 개선된 휨 성능 보강방법에 관한 연구이다. 이를 위하여 본 연구에서는 상대적으로 가격이 저렴한 알루미늄과 재료적 성능이 우수한 티타늄을 중간삽입제로 이용, 콘크리트와 보강재 사이의 부착하였으며 이들의 활용에 따른 휨 연성 개선과 콘크리트 박리파괴 지연에 대한 효과를 측정하였다.

• Tribology and Lubricants
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• 제30권2호
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• pp.77-85
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• 2014

This study set out to predict the load capacity and rotordynamic coefficients of tilting-pad journal bearings, taking the pivot stiffness into account. The analysis uses rocker-back (cylindrical) and ball in socket (spherical) pivot models, both of which are based on Hertzian contact stress theory. The models ascertain the non-linear elastic deformation of the pivots according to the applied load, pivot geometry, and material properties. At present, the Reynolds equation for an isothermal, isoviscous, and incompressible fluid is used to calculate the film pressure by using the finite-element method, after which the Newton-Raphson method is used to simultaneously find the journal center location, pad angles, and pivot deflections. The bearing analysis, excluding the pivot models, is validated using predictions those are readily available in the literature. As the rotor speed increases, the predicted journal eccentricity and damping coefficients decrease, but the stiffness coefficients increase, as expected. Most importantly, the implementation of the pivot models increases the journal eccentricity but significantly decreases the stiffness and damping coefficients of the tilting-pad journal bearings.

• Steel and Composite Structures
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• 제27권4호
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• pp.453-464
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• 2018

The objective of this study is to devise an alternative strengthening method to the ones available in the literature. So, external steel members were used to enhance both flexural and shear capacities of reinforced concrete (RC) beams having insufficient shear capacity. Two types of RC beams, one without stirrups and one with lacking stirrups, were prepared in the study. These beams were strengthened with external steel clamps devised by the authors and with external longitudinal reinforcements. Although the use of clamps alone didn't have a significant effect on the load carrying capacity of the tested beams, the ductility increased approximately tenfold and the failure behavior changed from brittle to ductile. Although the use of clamps and longitudinal reinforcements together did not significantly increase the ductility of the beams, it approximately doubled their load capacities. The results of the experimental study were compared to the ones obtained from nonlinear finite element analysis (NLFEA) and it was observed that they were compatible. Finally, it can be concluded that the devised method could be applied to structural members as an alternative to methods in application due to lightness, low-cost, easy applicable and reliable.

• 대한조선학회지
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• 제17권1호
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• pp.1-10
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• 1980

The nonlinear analysis of ship plating with flat bar stiffners has been carried out by the finite element method based on the load incremental approach. The large deflection analysis has been done by using the Lagrangian description. The elastoplastic analysis has been performed by adopting the flow theory of plasticity and the von Mises yield condition. The layered elements are used to show the process of yielding through the plate thickness in the elasto-plastic analysis. The following results are obtained; 1) According to the large deflection analysis, it is shown that the small deflection theory to the plate is applicable in the range of the lateral deflection-the thickness ratio $w/h{\leqq}0.3$ and ship plating in the range of $w/h{\leqq}0.5$. 2) By means of the elasto-plastic analysis, it is found that the maximum load-carrying capacity of the plate increases as much as 1.8 times of the initial yield load in the case of the simply supported condition and 2.2 times in the clamped condition. It is also shown that the maximum load-carrying capacity of ship plating increase as much as 4.3 times in the simply supported condition and 4.2 times in the clamped condition. This method would be applied and extended to solve combined nonlinear problems which involve both material nonlinearity and geometric nonlinearity.

• 한국농공학회논문집
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• 제54권5호
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• pp.103-111
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• 2012

In this study, the full-scale laboratory model test on utilization of recycled aggregates and crushed stone as vertical drains to use an alternative material of sand in soft ground is performed. The settlement and pore water pressure were measured to evaluate the discharge capacity and filed application, and the results were compared and analyzed through the finite element method. The measured and estimated settlement in all vertical drain materials decreases gradually with the load increase. The measured settlement 6.55~8.63 mm, and the estimated by the Hyperbolic model was 7.45~7.92 mm. So the model used for the analysis can be applied to the settlement estimation of the actual field. The variations of pore water pressure with time showed constantly regardless of the load in all vertical drainage materials. The pore water pressure was similarity to that of sand after rapid drawdown. Therefore, it was applicable to the field because discharge capacity was enough to be an alternative material to the sand which had been being used as the vertical drains.