• 제목/요약/키워드: Model Experimental Research

검색결과 4,750건 처리시간 0.035초

The RTD Measurement on a Submerged Bio-Reactor using a Radioisotope Tracer and the RTD Analysis

  • Seungkwon Shin;Kim, Jongbum;Sunghee Jung;Joonha Jin
    • International Journal of Control, Automation, and Systems
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    • 제1권2호
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    • pp.210-214
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    • 2003
  • This paper presents a residence time distribution (RTD) measurement method using a radioisotope tracer and the estimation method of RTD model parameters to analyze a submerged bio-reactor. The mathematical RTD models have been investigated to represent the flow behavior and the existence of stagnant regions in the reactor. Knowing the parameters of the RTD model is important for understanding the mixing characteristics of a reactor The radioisotope tracer experiment was carried out by injecting a radioisotope tracer as a pulse into the inlet of the reactor and recording the change of its concentration at the outlet of the reactor to obtain the experimental RTD response. The parameter estimation was performed by the Levenberg-Marquardt optimization algorithm. The proposed scheme allowed the parameter estimation of RTD model suggested by Adler-Hovorka with very low deviations. The estimation procedure is shown to lead to accurate estimation of the RTD parameters and to a good agreement between experimental and simulated response.

A methodology for remaining life prediction of concrete structural components accounting for tension softening effect

  • Murthy, A. Rama Chandra;Palani, G.S.;Iyer, Nagesh R.;Gopinath, Smitha
    • Computers and Concrete
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    • 제5권3호
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    • pp.261-277
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    • 2008
  • This paper presents methodologies for remaining life prediction of plain concrete structural components considering tension softening effect. Non-linear fracture mechanics principles (NLFM) have been used for crack growth analysis and remaining life prediction. Various tension softening models such as linear, bi-linear, tri-linear, exponential and power curve have been presented with appropriate expressions. A methodology to account for tension softening effects in the computation of SIF and remaining life prediction of concrete structural components has been presented. The tension softening effects has been represented by using any one of the models mentioned above. Numerical studies have been conducted on three point bending concrete structural component under constant amplitude loading. Remaining life has been predicted for different loading cases and for various tension softening models. The predicted values have been compared with the corresponding experimental observations. It is observed that the predicted life using bi-linear model and power curve model is in close agreement with the experimental values. Parametric studies on remaining life prediction have also been conducted by using modified bilinear model. A suitable value for constant of modified bilinear model is suggested based on parametric studies.

Type III 수소 저장 용기에서 난류 모델(Turbulence Model)에 따른 충전(Filling)현상의 수치 해석적 연구 (Numerical Analysis of Fillling Flow in Type III Hydrogen Tank with Different Turbulence Models)

  • 김무선;류준형;이성권;최성웅
    • 한국수소및신에너지학회논문집
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    • 제32권6호
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    • pp.483-488
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    • 2021
  • With continuous emission of environmental pollutants and an increase in greenhouse gases such as carbon dioxide, demand to seek other types of energy sources, alternative energy, was needed. Hydrogen, an eco-friendly energy, is attracting attention as the ultimate alternative energy medium. Hydrogen storage technology has been studied diversely to utilize hydrogen energy. In this study, the gas behavior of hydrogen in the storage tank was numerically examined under charge conditions for the Tpe III hydrogen tank. Numerical results were compared with the experimental results to verify the numerical implementation. In the results of pressure and temperature values under charge condition, the Realizable k-ε model and Reynold stress model were quantitatively matched with the smallest error between numerical and experimental results.

Analysis of signal cable noise currents in nuclear reactors under high neutron flux irradiation

  • Xiong Wu;Li Cai;Xiangju Zhang;Tingyu Wu;Jieqiong Jiang
    • Nuclear Engineering and Technology
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    • 제55권12호
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    • pp.4628-4636
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    • 2023
  • Cables are indispensable in nuclear power plants for transmitting data measured by various types of detectors, such as self-powered neutron detectors (SPNDs). These cables will generate disturbing signals that must be accurately distinguished and eliminated. Given that the cable current is not very significant, previous research has focused on SPND, with little attention paid to cable evaluation and validation. This paper specifically focuses on the quantitative analysis of cables and proposes a theoretical model to predict cable noise. In this model, the reaction characteristics between irradiated neutrons and cables were discussed thoroughly. Based on the Monte Carlo method, a comprehensive simulation approach of neutron sensitivity was introduced and long-term irradiation experiments in a heavy water reactor (HWR) were designed to verify this model. The theoretical results of this method agree quite well with the experimental measurements, proving that the model is reliable and exhibits excellent accuracy. The experimental data also show that the cable current accounts for approximately 0.2% of the total current at the initial moment, but as the detector gradually depletes, it will contribute more than 2%, making it a non-negligible proportion of the total signal current.

동기유발을 위한 ARCS 이론을 적용한 수업이 지구과학 학업성취도와 태도에 미치는 영향 (The Effects of the ARCS Model for Learners' Achivement and Motivation in Highschool Earth Science)

  • 박수경;김영환;김상달
    • 한국과학교육학회지
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    • 제16권4호
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    • pp.429-440
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    • 1996
  • This study examined the effects of the ARCS model for science education and found a way of improving ARCS while finding any weaknesses. More specific research questions were as follows: 1) Does the ARCS model enhance the learners' achivement in highschool Earth Science significantly?; 2) Does the ARCS model enhance the learners' motivation in highschool Earth Science significantly?; 3) What are the weaknesses of the prescriptions of the ARCS model for designing a lesson, if any?; 4) How can the weaknesses of the prescriptions of the ARCS modeI be overcome? In order to fulfill the purpose of this study, the two major research methodologies were implemented: pretest-posttest control group design and formarive research. This study was conducted in two distinct phases: 1) designing a set of instructions for 4 weeks with the principles of the ARCS model (to find the weaknesses of the ARCS model) and 2) teaching the instructions and checking the effectiveness of the ARCS model by pretest and posttest with control and experimental groups(to find weaknesses of the underlying theory of the ARCS). After the experiment, each group took an achievement test and an attitude test on the given instruction and gathered data were analyzed with t-tests. Also, from each four classes 7$\sim$8 students were randomly sampled and individually interviewed about the instructional effectiveness and their preference on the instructions. The results of this study are summarized as follows: Significant differences between the control group and experimental group are seen in three components; Attention, relevance, and satisfaction. No significant differences are seen in the attitude of confidence. The weakness of the prescriptions of the ARCS model, are insufficient of strategy for 'confidence'. For overcoming the weaknesses of the prescriptions of the ARCS model, developmental type research is needed.

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An improved polynomial model for top -and seat- angle connection

  • Prabha, P.;Marimuthu, V.;Jayachandran, S. Arul;Seetharaman, S.;Raman, N.
    • Steel and Composite Structures
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    • 제8권5호
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    • pp.403-421
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    • 2008
  • The design provisions for semi-rigid steel frames have been incorporated in codes of practice for steel structures. In order to do the same, it is necessary to know the experimental moment-relative rotation (M-${\theta}_r$) behaviour of beam-to-column connections. In spite of numerous publications and collection of several connection databases, there is no unified approach for the semi-rigid design of steel frames. Amongst the many connection models available, the Frye-Morris polynomial model, with its limitations reported in the literature, is simple to adopt at least for the linear design space. However this model requires more number of connection tests and regression analyses to make it a realistic prediction model. In this paper, 3D nonlinear finite element (FE) analysis of beam-column connection specimens, carried out using ABAQUS software, for evaluating the M-${\theta}_r$ behaviour of semi-rigid top and seat-angle (TSA) bolted connections are described. The finite element model is validated against experimental behaviour of the same connection with regard to their moment-rotation behaviour, stress distribution and mode of failure of the connections. The calibrated FE model is used to evaluate the performance of the Frye-Morris polynomial model. The results of the numerical parametric studies carried out using the validated FE model have been used in proposing modifications to the Frye-Morris model for TSA connection in terms of the powers of the size parameters.

Two-dimensional deformation measurement in the centrifuge model test using particle image velocimetry

  • Li, J.C.;Zhu, B.;Ye, X.W.;Liu, T.W.;Chen, Y.M.
    • Smart Structures and Systems
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    • 제24권6호
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    • pp.793-802
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    • 2019
  • The centrifuge model test is usually used for two-dimensional deformation and instability study of the soil slopes. As a typical loose slope, the municipal solid waste (MSW) landfill is easy to slide with large deformation, under high water levels or large earthquakes. A series of centrifuge model tests of landfill slide induced by rising water level and earthquake were carried out. The particle image velocimetry (PIV), laser displacement transducer (LDT) and marker tracer (MT) methods were used to measure the deformation of the landfill under different centrifugal accelerations, water levels and earthquake magnitudes. The PIV method realized the observation of continuous deformation of the landfill model, and its results were consistent with those by LDT, which had higher precision than the MT method. The deformation of the landfill was mainly vertically downward and increased linearly with the rising centrifugal acceleration. When the water level rose, the horizontal deformation of the landfill developed gradually due to the seepage, and a global slide surface formed when the critical water level was reached. The seismic deformation of the landfill was mainly vertical at a low water level, but significant horizontal deformation occurred under a high water level. The results of the tests and analyses verified the applicability of PIV in the two-dimensional deformation measurement in the centrifuge model tests of the MSW landfill, and provide an important basis for revealing the instability mechanism of landfills under extreme hydraulic and seismic conditions.

SYNERGISTIC INTERACTION OF ENVIRONMENTAL TEMPERATURE AND MICROWAVES: PREDICTION AND OPTIMIZATION

  • Petin, Vladislav G.;Kim, Jin-Kyu;Kolganova, Olga I.;Zhavoronkov, Leonid P.
    • Journal of Radiation Protection and Research
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    • 제36권1호
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    • pp.1-7
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    • 2011
  • A simple mathematical model of simultaneous combined action of environmental agents has been proposed to describe the synergistic interaction of microwave and high ambient temperature treatment on animal heating. The model suggests that the synergism is caused by the additional effective damage arising from an interaction of sublesions induced by each agent. These sublesions are considered to be ineffective if each agent is taken individually. The additional damage results in a higher body temperature increment when compared with that expected for an independent action of each agent. The model was adjusted to describe the synergistic interaction, to determine its greatest value and the condition under which it can be achieved. The prediction of the model was shown to be consistent with experimental data on rabbit heating. The model appears to be appropriate and the conclusions are valid.

Schematic of mean thickness distribution on the lateral aspect of the canine frontal sinus as an experimental model of sinus surgery

  • Bae, Jung-Hee;Kim, Han-Seok;Won, Sung-Yoon;Kim, Da-Hye;Jung, Ui-Won;Kim, Hee-Jin;Hu, Kyung-Seok
    • Anatomy and Cell Biology
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    • 제51권4호
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    • pp.236-242
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    • 2018
  • The dog frontal sinus may represent an alternative model dental implant research; its topographical resemblance to the maxillary sinus renders it a potentially favorable experimental environment. The aim of this study was thus to elucidate the anatomical configuration of the canine frontal sinus and histological characteristics, and to determine whether it could be a new canine experimental model for dental implant research. Twenty-four sides of canine frontal bones were harvested. The distance from the nasion to the emerging point of the lateral aspect of the canine frontal sinus was measured with the aid of Lucion software. The thicknesses of the canine frontal sinus wall were measured, and the two specimens stained with hematoxylin and eosin. The mean distance from the nasion to the emerging point of the lateral aspect of the canine frontal sinus was 16.0 mm. The mean thicknesses of the canine frontal bone at 3, 6, 9, 12, and 15 mm lateral to the midsagittal plane were 2.3, 2.7, 3.2, 3.8, and 3.7 mm, respectively. The canine frontal sinus was lined with pseudostratified ciliated columnar epithelium. These data suggest that the canine frontal sinus is a suitable alternative to the canine maxillary sinus as a model for studying various sinus augmentation protocols.

Experimental and numerical studies on concrete encased embossments of steel strips under shear action for composite slabs with profiled steel decking

  • Seres, Noemi;Dunai, Laszlo
    • Steel and Composite Structures
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    • 제11권1호
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    • pp.39-58
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    • 2011
  • The subject of the ongoing research work is to analyze the composite action of the structural elements of composite slabs with profiled steel decking by experimental and numerical studies. The mechanical and frictional interlocks result in a complex behaviour and failure under horizontal shear action. This is why the design characteristics can be determined only by standardized experiments. The aim of the current research is to develop a computational method which can predict the behaviour of embossed mechanical bond under shear actions, in order to derive the design characteristics of composite slabs with profiled steel decking. In the first phase of the research a novel experimental analysis is completed on an individual concrete encased embossment of steel strip under shear action. The experimental behaviour modes and failure mechanisms are determined. In parallel with the tests a finite element model is developed to follow the ultimate behaviour of this type of embossment, assuming that the phenomenon is governed by the failure of the steel part. The model is verified and applied to analyse the effect of embossment's parameters on the behaviour. In the extended investigation different friction coefficients, plate thicknesses, heights and the size effects are studied. On the basis of the results the tendencies of the ultimate behaviour and resistance by the studied embossment's characteristics are concluded.