• Structural Engineering and Mechanics
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• 제24권5호
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• pp.601-620
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• 2006

The paper presents an effective stiffness model for deformational analysis of reinforced concrete cracked members in bending throughout the short-term loading up to the near failure. The method generally involves the analytical derivation of an effective moment of inertia based on the smeared crack technique. The method, in a simplified way, enables us to take into account the non linear properties of concrete, the effects of cracking and tension stiffening. A statistical analysis has shown that proposed technique is of adequate accuracy of calculated and experimental deflections data provided for beams with small, average and normal reinforcement ratios.

• Nuclear Engineering and Technology
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• 제51권7호
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• pp.1715-1720
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• 2019

Jozef Stefan Institute (JSI), TRIGA Mark II reactor employs the homogeneous mixture of uranium and zirconium hydride fuel type. Since its upgrade, a series of fresh fuel steady state experimental benchmarks have been conducted. The benchmark results have provided data for testing computational neutronics codes which are important for reactor design and safety analysis. In this work, we investigated the JSI TRIGA Mark II reactor neutronics characteristics: the effective multiplication factor and two safety parameters, namely the control rod worth and the fuel temperature reactivity coefficient using SuperMC. The modeling and real-time cross section generation methods of SuperMC were evaluated in the investigation. The calculation analysis indicated the following: the effective multiplication factor was influenced by the different cross section data libraries; the control rod worth evaluation was better with Monte Carlo codes; the experimental fuel temperature reactivity coefficient was smaller than calculated results due to change in water temperature. All the results were in good agreement with the experimental values. Hence, SuperMC could be used for the designing and benchmarking of other TRIGA Mark II reactors.

• Journal of the Korean Wood Science and Technology
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• 제36권6호
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• pp.59-68
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• 2008

본 연구에서는 엔드테이핑(End-taping) 처리가 두께가 20~75 mm이고, 직경이 120~470 mm인 백합나무 원반들의 고주파진공건조중 건조결함 예방 미치는 영향에 대하여 조사하였다. Inside end-taping (Inside-ET)과 Outside end-taping (Outside-ET)의 경우 두께 33 mm, 직경 270 mm 이하 원반에서 할렬의 예방효과가 우수하게 나타났다. 직경이 30 cm 이하이고, 두께 60 mm와 두께 75 mm의 원반에서도 전처리을 통하여 경계할렬을 예방할 수 있을 것으로 기대되었다. 경계할렬의 발생위치는 0.50~0.63 diameter 지점으로서 직경에 따라서 상이하였으며, 따라서 횡단면의 부분 엔드테이핑 처리의 경계선도 원반의 직경 따라 적정하게 선정할 필요가 있는 것으로 조사되었다. 중경재의 경우 0.3 diameter 지점이 경계할렬 예방을 위한 전처리의 경계점일 가능성이 높을 것으로 해석된다. 대경재의 경우 경계할렬과 V형 크랙에 의한 손상이 매우 심하였으며, 이는 방사방향으로의 함수율 분포변이가 극심한 백합나무 고유의 재질특성에 기인한 것으로 해석된다. 따라서 대경재의 경우 원반으로 활용하는 것은 적절하지 않는 것으로 생각된다.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.424-427
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• 2017

This study investigated the effect of strain on hole mobility and hole effective mass in a p-channel rectangular nanowire with two-dimensional confinement. We obtained the valence energy band structure using the six-band k.p method and calculated the mobility and effective mass of the hole in the [100] direction taking the strain effect into account in the inversion region. The hole mobility of strained silicon was calculated using Kubo-Greenwood formalism. As a result, it showed good performance compared to relaxed silicon, but its magnitude was insignificant.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.291-294
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• 2005

In the present study, a numerical analysis was performed for interior connections of continuous flat plate to analyze the effect of column section shape on the behavioral characteristics of the connections. For the purpose, a computer program for nonlinear FE analysis was developed, and the validity was verified. Through the parametric study, the variations of shear stress distribution around the connection were investigated. According to the result of numerical analysis, the column section shape has a serious effect on the behavior of the connections. As the length of the cross section of column in the direction of lateral load increases, the effective area and the shear strength at the sides providing the torsional resistance decrease considerably. Therefore the strength model for the flat plate-column connections should be modified by considering the effect of column section shape on the behavior of the connections.

• Mass Spectrometry Letters
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• 제8권4호
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• pp.79-89
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• 2017

Ion mobility mass spectrometry (IM-MS) combines the advantages of ion mobility spectrometry (IMS) and MS for effective gas-phase ion analysis. Separation of ions based on their mobilities prior to MS can be performed without a great loss in other analytical figures of merit, and the extra dimension of analysis offered by IM can be beneficial for isomer and complex sample analyses. In this review, basic principles of IMS and IM-MS are described in addition to an introduction to various IMS techniques and commercial IM-MS instruments. The nature of collision cross-section (${\Omega}_D$), an important parameter determining the transport properties of ions in IMS, is also explained in detail.

• Computers and Concrete
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• 제34권1호
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• pp.49-61
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• 2024

The present study concerns a removal of chloride ions and structural behaviour of concrete beam at electrochemical chloride extraction (ECE). The electrochemical properties included 1000 mA/m2 current density for 2, 4 and 8 weeks. It was found that an increase in the duration of ECE resulted in an increase in the extraction rate of chlorides, in the range of 35-85%, irrespective of chloride contamination. In structural behaviour, the strength and maximum bending moment of specimen was always lowered by ECE. Moreover, the flexural rigidity and bending stiffness were reduced by the loss of effective cross-section area in the linear elastic range. Simultaneously, the inertia moment was substantially subjected to 70% loss of the cross-section by the tensile strain at the condition of the failure. However, a lower rate of the inertia moment reduction was achieved by ECE, implying the higher resistance to the cracking, but the higher risk of deformation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.605-610
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• 2002

The purpose of this study is to develop an analytic model which can describe the behavior or concrete compressive member strengthened by CFS(Carbon Fiber Sheet) with various cross-sectional shapes such as circular. square, and octagonal and various laminate angles. The failure criterion of laminated CFS is based on Tsai-Wu failure criterion. The stress strain model of confined concrete compressive member is based on an equation proposed by Mander. The effective lateral confining pressure is considered and modified according to various cross-sectional shapes. Octagonal cross-section shows the best results in the aspect of ductility, while circular does in compressive strengthening effects. In addition, [0/0/0/0] laminate in which the direction of fiber is parallel to the direction of principal stress shows the superior strength and ductility than other laminates. The analytic results show that strength and ductility of the analytic model depend on the cross-sectional shapes as well as the laminate angles.

• 한국구조물진단유지관리공학회 논문집
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• 제18권2호
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• pp.90-98
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• 2014

철근콘크리트 구조물의 전단거동은 수년간의 많은 연구에도 불구하고, 이론적으로 명확하게 규명하기에 어려운 문제중에 하나이다. 중공 슬래브의 휨강도와 전단강도는 중공부로 인하여 감소되기 때문에, 이에 따른 구조물의 성능을 예측하는 것은 중요한 문제라 할 수 있다. 현재 각국의 중공슬래브 전단설계기준은 실험에 의한 기준식을 제시하고 있다. 따라서 본 연구에서는 철근비에 따른 일방향 중공슬래브 전단강도 산정방법에 관한 연구를 수행하기 위해 실험결과를 분석하고, 전단강도 산정식들을 비교, 분석하였다.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2607-2612
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• 2020

The present work was aimed to show the possibility of using hydrogel (acrylic/boric acid) for evaluation of the neutron radiation shielding. The influence of acrylic acid concentration, different gamma doses and relative contents of boric acid were studied. The physical properties and the thermomechanical stability of the studied samples were investigated. The shielding property of the composite for neutron was tested by Pu-Be neutron source (5 Ci) under room temperature. The neutron fluence rates and gamma fluxes were measured using a stilbene organic scintillator. The macroscopic effective removal cross-section Σ_R (cm^-1) of fast neutrons and total attenuation coefficient μ (cm^-1) of gamma rays has been studied experimentally. The transmission parameters, the relaxation length (??) and the half-value layer (HVL) were obtained. The obtained results indicated that the addition of boric acid to acrylic acid tends to increase the macroscopic effective removal cross-section Σ_R (cm^-1) to 0.141 compared to 0.094 of ordinary concrete.