• International Journal of Concrete Structures and Materials
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• v.9 no.4
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• pp.463-473
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• 2015

Three full-scale instrumented test slabs were constructed and tested using a heavy vehicle simulator (HVS) to evaluate the structural behavior of internally cured concrete (ICC) for use in pavements under Florida condition. Three mix designs selected from a previous laboratory testing program include the standard mixture with 0.40 water-cement ratio, the ICC with 0.32 water-cement ratio, and the ICC mixture with 0.40 water-cement ratio. Concrete samples were prepared and laboratory tests were performed to measure strength, elastic modulus, coefficient of thermal expansion and shrinkage properties. The environmental responses were measured using strain gages, thermocouples, and linear variable differential transformers instrumented in full-scale concrete slabs. A 3-D finite element model was developed and calibrated using strain data measured from the full-scale tests using the HVS. The results indicate that the ICC slabs were less susceptible to the change of environmental conditions and appear to have better potential performance based on the critical stress analysis.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.146-146
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• 2009

• Proceedings of the Korean Geotechical Society Conference
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• 1998.10a
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• pp.305-312
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• 1998

• Membrane Journal
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• v.11 no.3
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• pp.97-108
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• 2001

Bipolar membranes have gained increasing interest as a tool for an efficient production of acids and bases from the corresponding salts. A large number of potential applications have been identified in the chemical and biochemical industry have been identified and evaluated on a laboratory scale. In spite of extensive research efforts and laboratory and pilot plat test, there are hardly any large-scale commercial plants. In this paper the basic concept of the electrodialytic water dissociation with bipolar membranes are briefly reviewed. The limitations of today\`s bipolar membranes are indicated. Selected examples of successful applications of the bipolar membrane technology are discussed.

• ETRI Journal
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• v.39 no.2
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• pp.292-299
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• 2017

We propose pulse-mode dynamic $R_on$ measurement as a method for analyzing the effect of stress on large-scale high-power AlGaN/GaN HFETs. The measurements were carried out under the soft-switching condition (zero-voltage switching) and aimed to minimize the self-heating problem that exists with the conventional hard-switching measurement. The dynamic $R_on$ of the fabricated AlGaN/GaN MIS-HFETs was measured under different stabilization time conditions. To do so, the drain-gate bias is set to zero after applying the off-state stress. As the stabilization time increased from $ 0.1{\mu}s$ to 100 ms, the dynamic $R_on$ decreased from $160\Omega$ to $2\Omega$. This method will be useful in developing high-performance GaN power FETs suitable for use in high-efficiency converter/inverter topology design.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.305-326
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• 2019

Discriminative correlation filter (DCF) based tracking algorithms have recently shown impressive performance on benchmark datasets. However, amount of recent researches are vulnerable to heavy occlusions, irregular deformations and so on. In this paper, we intend to solve these problems and handle the contradiction between accuracy and real-time in the framework of tracking-by-detection. Firstly, we propose an innovative strategy to combine the template and color-based models instead of a simple linear superposition and rely on the strengths of both to promote the accuracy. Secondly, to enhance the discriminative power of the learned template model, the spatial regularization is introduced in the learning stage to penalize the objective boundary information corresponding to features in the background. Thirdly, we utilize a discriminative multi-scale estimate method to solve the problem of scale variations. Finally, we research strategies to limit the computational complexity of our tracker. Abundant experiments demonstrate that our tracker performs superiorly against several advanced algorithms on both the OTB2013 and OTB2015 datasets while maintaining the high frame rates.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1902-1912
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• 2024

This paper presents results from system-level modeling of a water-based reactor cavity cooling system using RELAP5-3D. The computational model is benchmarked with experimental data from a half-scale RCCS test facility at Argonne National Laboratory. The model prediction is first compared with a two-phase oscillatory baseline experimental case where mixed accuracy is obtained. The model shows reasonable prediction of mass flow rate, pressure, and temperature but significant overprediction of void fraction. The model prediction is then compared with a fault case where the inlet of the risers is gradually reduced using a throttling valve. As the valve is closed, the model is able to predict some major flow phenomena observed in the experiment such as the dampening of oscillations, the reintroduction of oscillations, as well as boiling, flashing, and geysering in the risers. However, the timeline of these events are not well captured by the model. The model is also used to investigate the evolution of flow regime in the chimney. This work highlights that the semi-empirical constitutive relations used in RELAP-3D could have a strong influence on the accuracy of the model in two-phase oscillatory flows.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.2
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• pp.143-155
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• 2010

Fouling by inorganic scales needs to be prevented to effectively operate sea water reverse osmosis(SWRO) membrane systems. The extents of inorganic scaling with different array designs including one-pass, two-pass and several hybrid designs were evaluated using seawater from southern sea near the city of Chang-Won. The used methods for evaluation were Stiff and Davis Index(S&DSI) calculation and several laboratory experiments. The formation potential of inorganic scale fouling was quite great under the examined conditions, which was confirmed by the laboratory experimental results. The inorganic scale was not avoidable fouling if any anti-scaling measures were not applied. The RO showed decreased flux under the scale formation conditions. The increases in S&DSI from 1.43 to 5 made small decreases in flux, which indicated that formation of inorganic scales had more substantial effects on RO flux than amount of inorganic scales.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.3
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• pp.251-259
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• 2019

The aim of this study is to evaluate the economic feasibility of domestic on-site steam methane reforming (SMR) hydrogen refueling stations. We evaluated the levelized cost of hydrogen (LCOH) for the SMR hydrogen refueling stations, which have production capacities of 100 kg/day (SMR 100), 200 kg/day (SMR 200), and 500 kg/day (SMR 500) utilizing the scale factor. The main results indicated that the LCOH of SMR 100, SMR 200, and SMR 500 were 14,367 won/kg, 11,122 won/kg, and 8,157 won/kg, if the utilizations of hydrogen stations were 70%. These results imply that the production capacity of the domestic SMR hydrogen station should be greater than 500 kg/day to compete with other hydrogen stations when we consider the current sale price of hydrogen at the hydrogen stations.

• Steel and Composite Structures
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• v.49 no.5
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• pp.517-532
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• 2023

Tower structures have been widely used in communication and transmission engineering. The failure of joints is the leading cause of structure failure, which make it play a crucial role in tower structure engineering. In this study, the aluminum alloy three tube tower structure is taken as the prototype, and the middle joint of the tower was selected as the research object. Three different stainless steel-aluminum alloy composite joints (SACJs), denoted by TA, TB and TC, were designed. Finite element (FE) modeling analysis was used to compare and determine the TC joint as the best solution. Detail requirements of fasteners in the TC stainless steel-aluminum alloy composite joint (TC-SACJ) were designed and verified. In order to systematically and comprehensively study the mechanical properties of TC-SACJ under multi-directional loading conditions, the full-scale experiments and FE simulation models were all performed for mechanical response analysis. The failure modes, load-carrying capacities, and axial load versus displacement/stain testing curves of all full-scale specimens under tension/compression loading conditions were obtained. The results show that the maximum vertical displacement of aluminum alloy tube is 26.9mm, and the maximum lateral displacement of TC-SACJs is 1.0 mm. In general, the TC-SACJs are in an elastic state under the design load, which meet the design requirements and has a good safety reserve. This work can provide references for the design and engineering application of aluminum alloy tower structures.