• 한국환경과학회지
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• 제6권6호
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• pp.697-709
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• 1997

Sequencing Batch Reactor(SBR) experiments for organics and nutrients removal have been conducted to find an optimum anaerobic/anoxic/aerobic cycling time and evaluate the applicability of oxidation-reduction potential(ORP) as a process control parameter. In this study, a 61 bench-scale plant was used and fed with night-soil wastewater in K city which contained TCODcr : 10, 680 mg/l, TBm : 6, 893 mg/l, $NH_4^+-N$ : 1, 609 mg/l, $PO_4^{3-}-P$ : 602 mg/l on average. The cycling time In SBRs was adjusted at 12 hours and 24 hours, and then certainly included anaerobic, aerobic and inoxic conditions. Also, for each cycling time, we performed 3 series of experiment simultaneously which was set up 10 days, 20 days and 30 days as SRT From the experimental results, the optimum cycling time for biological nutrient removal with nlght-soil wastewater was respctively 3hrs, 5hrs, 3hrs(anaerobic-aerobic-anoxic), Nitrogen removal efficiency was 77.9%, 77.9%, 81.7% for each SRT, respectively. When external carbon source was fed in the anoxic phase, ORP-bending point indicating nitrate break point appeared clearly and nitrogen removal efficiency increased as 96.5%, 97.1%, 98.9%. Phosphate removal efficiency was 59.8%, 64.571, 68.6% for each SRT. Also, we finded the applicability of ORP as a process control parameter in SBRs.

• Structural Engineering and Mechanics
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• 제36권2호
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• pp.207-223
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• 2010

The aim of this study concerns with the construction stage analysis of highway bridges constructed with balanced cantilever method using time dependent material properties. K$\ddot{o}$m$\ddot{u}$rhan Highway Bridge constructed with balanced cantilever method and located on the 51st km of Elazi$\check{g}$-Malatya, Turkey, highway over Firat River is selected as an application. Finite element models of the bridge are modelled using SAP2000 program. Geometric nonlinearity is taken into consideration in the analysis using P-Delta plus large displacement criterion. The time dependent material strength variations and geometric variations are included in the analysis. Elasticity modulus, creep and shrinkage are computed for different stages of the construction process. The structural behaviour of the bridge at different construction stages has been examined. Two different finite element analyses with and without construction stages are carried out and results are compared with each other. As analyses result, variation of internal forces such as bending moment, axial forces and shear forces for bridge deck and column are given with detail. It is seen that construction stage analysis has remarkable effect on the structural behaviour of the bridge.

• 수산해양기술연구
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• 제19권2호
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• pp.117-124
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• 1983

정면규칙파중에서 Bow-flare부 충격은 선저충격에 비해서 작용 시간이 길고, 선체 수직운동진폭이 큰 상태이거나, 파고가 큰 입사파가 적용되는 경우에 선체에 작용하는 충격력은 상당히 크며, 파고가 높아지면, 발생하는 모우멘트도 증가한다. 2. Bow-flare부가 큰 선형의 경우에는 선저노출이 일어나지 않더라도 부가질량의 급격한 증가에 따라 상당히 큰 충격력이 작용한다. 3. Deckwetness, 불규칙파중에서의 응답해석, 상대변위를 구할 때 Dynamic Swell-up의 양을 고려한 계산 등의 검토가 요망된다.

• Structural Engineering and Mechanics
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• 제42권4호
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• pp.489-505
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• 2012

In this study, it is aim to perform the construction stage analysis of suspension bridges using time dependent material properties. Fatih Sultan Mehmet Suspension Bridge connecting the Europe and Asia in Istanbul is selected as an example. Finite element models of the bridge are modelled using SAP2000 program considering project drawing. Geometric nonlinearities are taken into consideration in the analysis using P-Delta large displacement criterion. The time dependent material strength variations and geometric variations are included in the analysis. Because of the fact that the bridge has steel structural system, only prestressing steel relaxation is considered as time dependent material properties. The structural behaviour of the bridge at different construction stages has been examined. Two different finite element analyses with and without construction stages are carried out and results are compared with each other. As analyses result, variation of the displacement and internal forces such as bending moment, axial forces and shear forces for bridge deck and towers are given with detail. It is seen that construction stage analysis has remarkable effect on the structural behaviour of the bridge.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.971-980
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• 2018

Using the concept of quasi-static decomposition and using three-noded isoparametric locking-free element, this article presents a formulation of the finite element method for Timoshenko beam subjected to spatially different time-dependent motions at supports. To verify the validity of the formulation, three fixed-hinged beams excited by the real seismic motions are examined; one is a slender beam, another is a stocky one, and the other is an intermediate one. The numerical results of time histories of motions of the three beams are compared with corresponding analytical solutions. The internal loads such as bending moment and shearing force at a specific time are also compared with analytic solutions. These comparisons show good agreements. The comparisons between static components of the internal loads and the corresponding total internal loads show that the static components predominate in the stocky beam, whereas the dynamic components predominate in the slender one. Thus, the total internal loads of the stocky beam, which is governed by static components, can be predicted simply by static analysis. Careful numerical experiments indicate that the fundamental frequency of a beam can be used as a parameter identifying such a stocky beam.

• Steel and Composite Structures
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• 제43권6호
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• pp.809-819
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• 2022

This paper proposes a method to predict the deflection of prestressed concrete (PC) beams with corrugated steel web (CSW) under constant load concerning time-dependent variation in concrete material. Over time, the top and bottom concrete slabs subjected to asymmetric compression experience shrinkage and creep deformations. Here, the classical Euler-Bernoulli beam theory assumption that the plane sections remain plane is not valid due to shear deformation of CSW. Therefore, this study presents a method based on the first-order shear deformation to find the long-term deflection of the composite beams under bending by considering time effects. Two experimental prestressed beams of this type were monitored under their self-weight over time, and the theoretical results were compared with those data. Additionally, 3D analytical models of the experimental beams were used according to material properties, and the results were compared with two previous cases. There was good consistency between the analytical and numerical results with low error, which increased by wave radius. It is concluded that the proposed method could reliably be used for design purposes.

• Journal of the Korean Wood Science and Technology
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• 제12권2호
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• pp.20-26
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• 1984

내화처리(耐火處理)된 합판(合板)의 내부(內部)에 잔존(殘存)하고 있는 내화약제(耐火藥劑)의 종류(種類) 및 그 양(量)이 합판(合板) 특유(特有)의 장점(長點)인 휨 강도(强度)에 어떠한 영향(影響)을 미치는 가를 조사(調査)하기 위(爲)해 황산(黃酸) 암모늄(Ammonium sulfate), 제1인산(第一燐酸) 암모늄(Ammonium phosphate, mono basic), 제2인산(第二燐酸) 암모늄(Ammonium phosphate, di basic), 그리고 복합약제(複合藥劑)인 붕사(硼砂) 붕산(硼酸)(Borax-Boric acid) 및 미나리스(Minalith) 등(等) 5종(種)의 내화제(耐火劑)를 20% 수용액(水溶液)으로 조제(調劑)한 다음 3.5mm 메란티 합판(合板)을 3시간(時間)부터 12시간(時間) 동안 3시간(時間) 간격(間隔)으로 침지처리(浸漬處理)를 한 후(後) $120^{\circ}C$의 열판(熱板)으로 재건조(再乾燥)하여 휨 강도시험(强度試驗)을 행(行)하였다. 비례한계(比例限界)에서의 응력(應力), 탄성계수(彈性係數), 파괴계수(破壞係數) 및 비례한계(比例限界)까지의 단위체적(單位體積) 당(當) 일등(等)을 조사(調査)한 바, 약제처리(藥劑處理)한 합판(合板)의 경우가 수분처리합판(水分處理合板)(대희구(對熙區))에 비(比)해 대부분(大部分) 높게 나타났으며 붕사(硼砂) 붕산(硼酸) 처리합판(處理合板)의 경우가 4부간(部間)에서 공(共)히 가장 높은 치(値)를 보여주었다. 그리고 처리시간(處理時間)이 연장(延長)됨에 따라, 즉 약액(藥液)의 흡수량(吸收量)(약제(藥劑) 잔존량(殘存量))이 증가(增加)함에 따라 휨 강도(强度)는 대체적(大體的)으로 향상(向上)하는 것으로 나타났다. 강도적(强度的) 측면(側面)이나 침지처리시(浸漬處理時) 발생(發生)하는 결함(缺陷) 등을 고려(考慮)할 때 복합약제(複合藥劑)인 붕사(硼砂) 붕산(硼酸)이 가장 바람직한 합판용(合板用) 내화처리약제(耐火處理藥劑)로 사료되는 바이다.

• 한국실내디자인학회논문집
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• 제27권1호
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• pp.29-38
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• 2018

This research is to analyze the change of pupil size in gender through the eye-tracking experiment in large complex cultural space. It is meaningful that figured out the common characteristics and differences from gender observation characteristics. Through this research, the analyzed results of the observation time measurement that appeared from the fixation and saccades pupil indicator able to define as follows. Firstly, it was suggested that there were differences between each gender and participants through extract pupil size that can be the standard examples for the case from male and female and the process of extracting the relative pupil size change on the hourly range. From the specific time range, it was possible to indicate bending characteristics and reversal phenomena of Fixation and Saccades. Second, the result was found equally from both male and female group that the rapid increment of pupil size at initial time range immediately after the eye-tracking experiment has been initiated. This can be considered to actively accepting the stress given by the subject through the extended pupil after 10 seconds that compare to indicated very low pupil size between 0 to 10 seconds after starting the experiment. Third, meanwhile 0 to 10 seconds after initial observation are the time of sudden change in the pupil size, therefore these time range data cannot be regarded as observed in the appropriate condition. Thus, it able to define the highest times of emotional processing for male as 10 to 80 seconds, and for female as 10 to 70 seconds. There was no definition of the time range data for observation experiment from previous research, this data can be considered to stable time to observation through the pupil extension. Therefore, it is possible to set suitable time of observation experiment to be around 70 to 80 seconds exclude initial experiment time.

• 콘크리트학회논문집
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• 제24권6호
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• pp.633-641
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• 2012

이 논문에서는 비탄성 시간이력해석을 통해 보-기둥 접합부 비탄성 전단거동이 구조물 거동에 미치는 영향을 알아보기 위해 지반조건 $S_B$ 내진설계범주 C에 대해서 5층 철근콘크리트 보통모멘트골조를 KBC2009에 맞게 구조설계 하였다. 보 및 기둥 부재의 휨모멘트-곡률 관계는 fiber model로 확인하였으며 보-기둥 접합부 모멘트-회전각 관계는 simple and unified joint shear behavior model과 보-기둥 접합부 모멘트 평형관계를 이용하여 확인하였다. 이력거동은 IDARC 프로그램의 three-parameter model을 활용하여 나타내었다. 2400년 재현주기 수준의 최대지반가속도에 대한 비탄성 시간이력해석 결과 비탄성 보-기둥 접합부를 고려하는 경우 최대밑면전단력은 감소하나 최대지붕층변위, 최대층간변위는 차이가 없었으며 발생한 최대층간변위도 KBC2009의 허용층간변위를 만족하여 구조설계 과정에서 보-기둥 접합부의 비탄성 전단거동을 고려하지 않아도 문제가 없을 것으로 판단된다.

• 한국강구조학회 논문집
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• 제22권3호
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• pp.281-291
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• 2010

본 연구에서는 횡력을 받는 구조물 거동에 대한 보-기둥 접합부의 영향을 확인하기 위하여 5층 철골구조물을 KBC2005 건축구조 설계기준에 맞게 구조설계 하였으며 접합부를 완전 강접합부로 이상화한 경우와 반강접 접합부로 설계하였다. 철골 보 및 기둥의 모멘트-곡률관계는 화이버모델을 이용하여 확인하였으며 반강접 접합부의 모멘트-회전각 관계는 파워모델 그리고 철골 보, 기둥 및 접합부의 이력거동은 3-매개변수 모델을 이용하여 나타내었다. 5층 철골구조물은 개별골조와 연결골조의 2차원 구조물로 이상화하였다. 4개 지진파의 재현주기 수준별로 산정한 최대지반가속도와 푸쉬오버해석의 최대밑면전단력을 위한 지반가속도에 대하여 시간이력해석을 실시하여 지붕층 변위, 밑면전단력, 층간변위, 접합부 요구연성도, 기둥, 보 및 접합부의 최대모멘트 그리고 소성힌지 분포 등을 확인하였다. 반강접 접합부 골조는 완전 강접합 골조에 비해 적은 밑면전단력이 발생하였으며 기둥, 보 및 접합부에 발생하는 휨모멘트의 크기와 증가율도 적었다. TSD 접합부는 우리나라 설계수준의 지진하중에 대하여 예제 구조물에서 경제성과 안전성을 확보 할 수 있음을 확인할 수 있었다.