• Steel and Composite Structures
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• 제42권2호
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• pp.209-219
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• 2022

Offshore platforms in seismically active areas must be designed to survive in the face of intense earthquakes without a global structural collapse. This paper scrutinizes the seismic performance of a newly designed and established jacket type offshore platform situated in the entrance of the Gulf of Suez region based on the API-RP2A normalized response spectra during seismic events. A nonlinear finite element model of a typical jacket type offshore platform is constructed taking into consideration the effect of structure-soil-interaction. Soil properties at the site were manipulated to generate the pile lateral soil properties in the form of load deflection curves, based on API-RP2A recommendations. Dynamic characteristics of the offshore platform, the response function, output power spectral density and transfer functions for different elements of the platform are discussed. The joints deflection and acceleration responses demands are presented. It is generally concluded that consideration of the interaction between structure, piles and soil leads to higher deflections and less stresses in platform elements due to soil elasticity, nonlinearity, and damping and leads to a more realistic platform design. The earthquake-based analysis for offshore platform structure is essential for the safe design and operation of offshore platforms.

• Applied Microscopy
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• 제47권3호
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• pp.110-120
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• 2017

Non-isothermal thermogravimetry (TG) measurements on melt-quenched $Bi_xSe_{100-x}$ specimens (x=0, 2.5, 7.5 at%) were made at a heating rate ${\beta}=10^{\circ}C/min$ in the range $T=35^{\circ}C{\sim}950^{\circ}C$. The as-measured TG curves confirm that $Bi_xSe_{100-x}$ samples were thermally stable with minor loss at $T{\leq}400^{\circ}C$ and mass loss starts to decrease up to $600^{\circ}C$, beyond which trivial mass loss was observed. These TG curves were used to estimate molar (Se/Bi)-ratios of $Bi_xSe_{100-x}$ samples, which were not in accordance with initial composition. Shaping features of conversion curves ${\alpha}(T)-T$ of $Bi_xSe_{100-x}$ samples combined with a reliable flow chart were used to reduce kinetic mechanisms that would have caused their thermal mass loss to few nth-order reaction models of the form $f[{\alpha}(T)]{\propto}[1-{\alpha}(T)]^n$ (n=1/2, 2/3, and 1). The constructed ${\alpha}(T)-T$ and $(d{\alpha}(T)/dT)-T$ curves were analyzed using Coats-Redfern (CR) and Achar-Brindley-Sharp (ABS) kinetic formulas on basis of these model functions, but the linearity of attained plots were good in a limited ${\alpha}(T)-region$. The applicability of CR and ABS methods, with model function of kinetic reaction mechanism R0 (n=0), was notable as they gave best linear fits over much broader ${\alpha}(T)-range$.

• Journal of Microbiology
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• 제42권2호
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• pp.126-132
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• 2004

A single chain variable fragment (scFv) specific towards B. pseudomallei exotoxin had previously been generated from an existing hybridoma cell line (6E6AF83B) and cloned into the phage display vector pComb3H. In this study, the scFv was subcloned into the pComb3X vector to facilitate the detection and purification of expressed antibodies. Detection was facilitated by the presence of a hemagglutinin (HA) tag, and purification was facilitated by the presence of a histidine tag. The culture was grown at 30$^{\circ}C$ until log phase was achieved and then induced with 1 mM IPTG in the absence of any additional carbon source. Induction was continued at 30$^{\circ}C$ for five h. The scFv was discerned by dual processes-direct enzyme-linked immunosorbent assays (ELISA), and Western blotting. When compared to E. coli strains ER2537 and HB2151, scFv expression was observed to be highest in the E. coli strain Topl0F'. The expressed scFv protein was purified via nickel-mediated affinity chromatography and results indicated that two proteins a 52 kDa protein, and a 30 kDa protein were co-purified. These antibodies, when blotted against immobilized exotoxin, exhibited significant specificity towards the exotoxin, com-pared to other B. pseudomallei antigens. Thus, these antibodies should serve as suitable reagents for future affinity purification of the exotoxin.

• 토지주택연구
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• 제6권3호
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• pp.129-138
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• 2015

최근 국내의 건축구조는 공간활용을 극대화할 수 있도록 계획되고 있다. 공간활용의 장점을 실현하기 위하여 하이브리드 OCB(Optimized Composite Beam)보를 개발하였다. 본 논문에서 개발된 건축용 OCB보는 부모멘트 구간에서는 노출강연선으로 보강된 H형강으로 구성되고 정모멘트 영역에서는 프리텐션 방식의 PSC 구조로 구성된다. 본 연구에선 유한요소법을 이용하여 건축용 OCB보의 휨성능을 조사하였다. 15m, 20m, 30m 길이의 OCB모형을 구성하여 재료 및 기하학적 비선형 정적해석을 수행하였다. 해석결과로부터 다음과 같은 결과를 얻었다. 1)해석모델의 초기균열은 사용하중이상에서 모두 발생되었다. 2)사용하중단계에서 처짐은 건축구조설계기준에 제시된 허용처짐량 이내로 만족하였다. 3)유한요소모델의 파괴 시 극한하중은 모두 단면의 설계공칭강도 이상에서 발생되었다. 해석결과로부터 건축용 OCB보의 구조적인 신뢰성이 입증되었다.

• Computers and Concrete
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• 제34권1호
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• pp.33-48
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• 2024

This paper presents the detailed experimental and analytical investigation on the evolution of static (E_s) and dynamic modulus of elasticity (E_d) of concrete having 0%, 35%, and 50% FA used as partial cement replacement. Destructive and non-destructive tests were conducted on cylindrical specimens to evaluate the compressive strength and MoE of concrete in compression at the age of 28, 56, 90, and 150 days for all mixes. Experimental results show that the concrete having 35% FA achieved compressive strength and MoE similar to plain concrete at the age of 90 days, while 50% FA concrete attained satisfactory compressive strength and MoE at the age of 150 days. The comprehensive statistical analysis has been carried out in two ways on the basis of the experimental results. Firstly, the 28-day crushing strength of plain concrete in compression was used to design the models for the prediction of E_s and E_d of fly ash concrete at any age and percentage replacement of FA. Secondly, using the values of UPV and RHN, models have been developed to predict the age or time-dependent E_s and E_d of fly ash concrete. These models will be helpful in assessing the E_s and E_d of fly ash concrete without knowing the 28-day crushing strength of plain concrete in compression in the laboratory. Hence, the suggested models in the present study will be beneficial in conducting the health assessment of fly ash based concrete structures.

• Journal of Nutrition and Health
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• 제53권6호
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• pp.583-595
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• 2020

본 연구에서는 괭생이 모자반 추출물의 소포체 스트레스 억제 효능을 연구하기 위하여 HepG2 간세포에 PA를 처리하여 소포체 스트레스를 유발한 후 추출물을 처리하여 UPR 관련 인자 발현 정도를 측정하였다. PA 750 μM 처리 시 UPR 관련 인자 (p-IRE1α, p-eIF2α, CHOP)의 단백질 발현이 가장 높게 나타나 소포체 스트레스를 효과적으로 유도함을 확인하였고 PA 750 μM를 12시간 처리 시 UPR 관련 인자 (p-IRE1α, p-eIF2α, CHOP)의 단백질 발현이 가장 높음을 확인하였다. 괭생이 모자반 처리 시 PA에 의해 상향 조절된 UPR 관련 인자의 mRNA 및 단백질 발현이 감소하여 PA로 유도된 소포체 스트레스에 대한 억제 효능이 있음을 보여주었다. 또한, 괭생이 모자반은 SIRT2, SIRT6 및 SIRT7의 mRNA의 발현을 증가시킴으로써 괭생이 모자반의 소포체 스트레스 억제 효능이 SIRT에 의한 것으로 확인되었다. 이러한 결과는 괭생이 모자반이 다양한 소포체 스트레스 관련 질병의 예방과 치료에 활용가능성이 있음을 시사한다.

• 생명과학회지
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• 제15권4호
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• pp.626-632
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• 2005

폴리아민은 모든 진핵세포에서 발견되는 다가 양이온성의 저분자 물질이며 세포성장에 필수적인 것으로 알려져 있다. 본 논문에서는 폴리아민의 역할 중에서 산화적인 스트레스에 대한 세포보호 효과를 연구하였다. 쥐의 간세포주인 $Ac_2F$에 산화 스트레스를 유발하기 위하여 2,2'-azobis(2-amidinopropane)dehydrochloride (AAPH)를 처리하였을 때, 세포증식은 농도 의존적으로 감소하였다. 배지에 폴리아민을 첨가하였을 때 세포성장은 농도 의존적으로 증가하였으며 ROS 발생은 현저히 감소하였다. 폴리아민 가운데 특히 spermidine과 spermine이 뚜렷한 세포증식효과를 보였다. Spermine의 경우, $20{\mu}M$농도에서 AAPH에 의해 유도된 ROS발생을 $45\%$나 감소시켰다. 산화 스트레스에 관여하는 효소들 가운데 주된 효소인 superoxide dismutate (SOD)와 catalase (CAT)의 세포 내 단백질을 Western blotting으로 조사한 결과, AAPH는 이 두 가지 단백질의 생성을 억제한 것으로 나타났다. 그러나 spermine을 처리하였을 때 두 단백질의 생산은 모두 정상적으로 회복이 되었다. 또한 세포주기의 중요한 조절 단백질인 cyclin E 역시 AAPH에 의하여 생성이 억제되었다. 이는 AAPH에 의하여 생성된 ROS가 세포주기의 S phase의 진행을 억제한 것으로 생각된다. AAPH에 의한 cyclin E의 억제는 spermine에 의하여 정상적으로 회복되었다. 위와 같은 Spermine의 항산화 효과는 ethidium bromide와 acridine orange를 이용하여 형태학적으로도 증명되었다.

• Earthquakes and Structures
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• 제1권1호
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• pp.109-127
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• 2010

This work aims at introducing structural sensitivity analysis capabilities into existing commercial finite element software codes for the purpose of mapping retrofit strategies for a broad group of structures including heritage-type buildings. More specifically, the first stage sensitivity analysis is implemented for the standard deterministic environment, followed by stochastic structural sensitivity analysis defined for the probabilistic environment in a subsequent, second phase. It is believed that this new generation of software that will be released by the industrial partner will address the needs of a rapidly developing specialty within the engineering design profession, namely commercial retrofit and rehabilitation activities. In congested urban areas, these activities are carried out in reference to a certain percentage of the contemporary building stock that can no longer be demolished to give room for new construction because of economical, historical or cultural reasons. Furthermore, such analysis tools are becoming essential in reference to a new generation of national codes that spell out in detail how retrofit strategies ought to be implemented. More specifically, our work focuses on identifying the minimum-cost intervention on a given structure undergoing retrofit. Finally, an additional factor that arises in earthquake-prone regions across the world is the random nature of seismic activity that further complicates the task of determining the dynamic overstress that is being induced in the building stock and the additional demands placed on the supporting structural system.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1991년도 추계학술발표회 논문집 지반공학에서의 컴퓨터 활용 COMPUTER UTILIZATION IN GEOTECHNICAL ENGINEERING
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• pp.312-331
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• 1991

런던시내의 역사적 건물들 주변에서 LONDON CLAY층을 굴착하고 지하 5층의 주차장 건설에 TOP-DOWN공법이 적용되었다. 인접 구조물들의 안전진단을 수치해석(F.E.M)으로 예측하고 현장에서 실측한 자료와 비교분석하였다. 사용된 탄소성 COMPUTER 모델은 현장계측값들과 비교적 잘 일치하고 있으며, 지하 연속벽(DIAPHRAGM WALL)을 이용한 TOP-DOWN공법이 주변지반 변형을 감소시킬 수 있는 가장 효과적인 방법으로 판명되었다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권3호
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• pp.104-109
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• 1999

In order to design and predict the performance of the harmonic side drive motor, it is necessary to analyze the torque generated by the structure. In this paper, an analytical model is proposed for design. Conformal mapping is used to model the capacitance and torque of the motor as a function of the rotor angular position with two-dimensional approximation. Then the result of conformal mapping analysis is verified with F.E.M result.