• Journal of Institute of Control, Robotics and Systems
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• v.12 no.11
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• pp.1119-1123
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• 2006

The flame image processing and analysis system has been investigated for the optimal pulverized coal firing of thermal power plant, especially for lower nitrogen oxide generation and more safe operation. We aimed at gaining the relationship between burner flame image information and emissions of nitrogen oxide and unburned carbon in furnace utilizing the flame image processing methods, by which we quantitatively determine the condition of combustion on the individual humors. Its feasibility test was undertaken with a pilot furnace for coal firing, through which the system was observed to be effective for the monitoring of the combustion condition of pulverized coal firing boilers.

• Advances in concrete construction
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• v.8 no.3
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• pp.165-172
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• 2019

Progressive collapse is one of the factors which if not predicted at the time of structure plan; its occurrence will lead to catastrophic damages. Through having a glance over important structures chronicles in the world, we will notice that the reason of their collapse is a minor damage in structure caused by an accident like a terrorist attack, smashing a vehicle, fire, gas explosion, construction flaws and its expanding. Progressive collapse includes expanding rudimentary rupture from one part to another which leads to total collapse of a structure or a major part it. This study examines the progressive collapse of a 5-story concrete building with three column eliminating scenarios, including the removal of the corner, side and middle columns with the ABAQUS software. Then the beams and the bottom of the concrete slab were reinforced by (reinforcement of carbon fiber reinforced polymer) FRP and then the structure was re-analyzed. The results of the analysis show that the reinforcement of carbon fiber reinforced polymer sheets is one of the effective ways to rehabilitate and reduce the progressive collapse in concrete structures.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.67-75
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• 2021

This work studies the behaviour of a steel portal frame selection under fire exposure, considering both span lengths and fire exposure times as variables. Such structures combine carbon steel (S275), fireproof micro-alloyed steel (FR), and coatings of intumescent paint with variable thicknesses, improving thereby the flame retardant behaviour of the steel structure. Thus, the main contribution of this study is the optimization of the portal frames by combining both steels, analysing the resulting costs influence on the final dimensions. Besides, the topological optimization of each steel component within the structure is also defined, in accordance with the following variables: weather conditions, span, paint thickness, and cost of steel. The results mainly confirmed that using both FR and S275 grades with intumescent painting is the Pareto optimum when considering performance, feasibility and costs of such portal frames widely used for industrial facilities.

• Environmental Analysis Health and Toxicology
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• v.20 no.4 s.51
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• pp.259-271
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• 2005

Engineered nanoparticles exhibit a variety of unique and tunable chemical and physical properties. These unique properties make the nanoparticles central components and widespread potential applications in nanoindustry. However, the potential toxicities of nanoparticles have not been fully evaluated. Recently, the impacts of nanoparticles to human and environment became the emerging issue of toxicology. In this article, physicochemical properties and toxicities of carbon nanotube, fullerene, quantum dots, and other types of nanomaterials were reviewed and the strategy of risk assessment were suggested based on the frame of chemical assessment.

• Proceedings of the Korean Magnestics Society Conference
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• 2014.11a
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• pp.137-137
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• 2014

• Journal of the Korean Society for Advanced Composite Structures
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• v.5 no.1
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• pp.28-36
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• 2014

This study describes the development of innovative connections between steel beams and concrete-filled tube columns that utilize a combination of low-carbon steel and super-elastic shape memory alloy components. The intent is to combine the recentering behavior provided by the shape memory alloys to reduce building damage and residual drift after a major earthquake with the excellent energy dissipation of the low-carbon steel. The analysis and design of structures requires that simple yet accurate models for the connection behavior be developed. The development of a simplified 2D spring connection model for cyclic loads from advanced 3D FE monotonic studies is described. The implementation of those models into non-linear frame analyses indicates hat the recentering systems will provide substantial benefits for smaller earthquakes and superior performance to all-welded moment frames for large earthquakes.

• Journal of Microbiology and Biotechnology
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• v.8 no.1
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• pp.14-20
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• 1998

Syntheses of the B. stearothermophilus xylanolytic enzymes such as xylanases, ${\beta}$-xylosidases, ${\alpha}$-arabinofurano-sidases, and esterases, were observed to be regulated by the carbon source present in the culture media. Xylan induced synthesis of ${\beta}$-xylosidase at the highest level while xylose gave about 30% of the ${\beta}$-xylosidase activity induced by xylan. The lowest syntheses of the xylanolytic enzymes above mentioned were detected in the basal medium containing glucose as a sole carbon source. When a mixture of xylan and glucose was used as a carbon source, we could observe glucose repression of xylanase (about 70-fold) and ${\beta}$-xylosidase (about 40-fold) syntheses. Whereas, the level of the glucose repression of the expression of the xylA gene encoding the major ${\beta}$-xylosidase of B. stearothermophilus was assessed to be about l0-fold when the relative amounts of the xylA transcript were determined. From the sequence of the xylA gene, we could find two CRE-like sequences (CRE-l: nucleotides ＋124 to ＋136 and CRE-2:＋247 to ＋259) within the reading frame of the xylA gene, either or both of which were suspected to be involved in catabolite repression of the xylA gene.

• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.177-182
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• 2018

In this paper, the fracture behaviour at CFRP laminated structure due to the vertical falling impact of the fight drone frame composed of CFRP was investigated through the analytical study. As CFRP consists of fiber differently from the existing plastic material, the fracture behaviour becoms complex. So, the preceding study is important through the analytical study before this experiment. By comparing with the existing study model at the same condition as the result of this study, the applied stress value is shown to decrease greatly at the analysis model with the center notch hole of the laminated CFRP drone frame. On the basis of this study result, the esthetic sense can be shown as the foundation data about the notch hole of drone frame are grafted onto the convergence technique.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.265-270
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• 2013

Strength design for a lightweight bicycle frame made of carbon/epoxy composite laminates was studied using Tsai-Wu's failure criterion. For the design of bicycle frames, reducing the weight of the frame is of great importance. Furthermore, the frame should satisfy the required strength under specific loading cases. In accordance with the European EN 14764 standard for bicycle frames, three loading cases-pedaling, vertical, and level loadings-were investigated in this study. Because of the anisotropic characteristics of composite materials, it is important to decide the appropriate stacking sequence and the number of layers to be used in the composite bicycle frame. From finite element analysis results, the most suitable stacking sequence of the fiber orientation and the number of layers were determined. The stacking sequences of $[0]_{8n}$, $[90]_{8n}$, $[0/90]_{2ns}$, $[{\pm}45]_{2ns}$, $[0/{\pm}45/90]_{ns}$ (n = 1, 2, 3, 4) were used in the analysis. The results indicated that the $[0/{\pm}45/90]_{3s}$ lay-up model was suitable for a composite bicycle frame. Furthermore, the weakest point and layer were investigated.

• Earthquakes and Structures
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• v.20 no.2
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• pp.215-224
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• 2021

The carbon dioxide present in the atmosphere is one of the main reasons for the corrosion of bridges, buildings, tunnels, and other reinforced concrete (RC) structures in most industrialized countries. With the growing use of fossil fuels in the world since the Industrial Revolution, the amount of carbon dioxide in urban and industrial areas of the world has grown significantly, which increases the chance of corrosion caused by carbonation. The process of corrosion leads to a change in mechanical properties of rebars and concrete, and consequently, detrimentally impacting load-bearing capacity and seismic behavior of RC structures. Neglecting this phenomenon can trigger misleading results in the form of underestimating the seismic performance metrics. Therefore, studying the carbonation corrosion influence on the seismic behavior of RC structures in urban and industrial areas is of great significance. In this study, a 2D modern RC moment frame is developed to study and assess the effect of carbonation corrosion, in 5-year intervals, for a 50 years lifetime under two different environmental conditions. This is achieved using the nonlinear static and incremental dynamic analysis (IDA) to evaluate the reinforcement corrosion effects. The reduction in the seismic capacity and performance of the reinforced concrete frame, as well as the collapse probability over the lifetime for different corrosion scenarios, is examined through the capacity curves obtained from nonlinear static analysis and the fragility curves obtained from IDA.