• Structural Engineering and Mechanics
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• v.36 no.4
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• pp.447-461
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• 2010

Fiber reinforced polymer (FRP) bars have been widely used as reinforcement for concrete structures. However, under elevated temperatures, the difference between the transverse coefficients of thermal expansion of FRP rebars and concrete may cause the splitting cracks of the concrete cover. As a result, the bonding of FRP-reinforced concrete may not sustain its function to transfer load between the FRP rebar and the surrounding concrete. The current study investigates the cracking resistance of FRP reinforced concrete against the thermal expansion based on a mechanical model that accounts for the tensile softening behavior of concrete. To evaluate the efficacy of the proposed model, the critical temperature increments at which the splitting failure of the concrete cover occurs and the internal crack radii estimated are compared with the results obtained from the previous studies. Simplified equations for estimating the critical temperature increments and the minimum concrete cover required to prevent concrete splitting failure for a designated temperature increment are also derived for design purpose.

• Culinary science and hospitality research
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• v.15 no.1
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• pp.296-308
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• 2009

According to Lee In-ja's research into the cooks of Korea, there are more than 1.2 million culinary professionals in Korea. However, it is hard to find studies on their work environment. From this point, this study aims to examine the shoes worn by culinarians in their workplace and facilitate the improved environment to protect culinary professionals against potential dangers such as slips, occupational and industrial injuries and fatigue, on the basis of the shoes they wear. The research was conducted on a representative cross section of safety shoes currently worn by culinary professionals. The four factors to be tested and measured for the study were weight, slip resistance, internal tearing strength and splitting resistance. Findings on inquiry showed that the shoes tested were quite heavy, slippery and readily liable to splitting under low stress - when compared to standardized base figures. In accordance with the results of this experiment, guidelines for four factors of manufacture were suggested. First, chef's shoes should weigh not more than 1% of a wearers weight. Second, they should exhibit more than 0.50 $\mu$ slip resistance. Third, they should withstand at least 50.0 N/mm tearing strength. And finally, they should have upwards of 3.0 kg/cm splitting resistance.

• International Journal of Concrete Structures and Materials
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• v.8 no.4
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• pp.301-307
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• 2014

Rice husk ash (RHA) is classified as a highly reactive pozzolan. It has a very high silica content similar to that of silica fume (SF). Using less-expensive and locally available RHA as a mineral admixture in concrete brings ample benefits to the costs, the technical properties of concrete as well as to the environment. An experimental study of the effect of RHA blending on workability, strength and durability of high performance fine-grained concrete (HPFGC) is presented. The results show that the addition of RHA to HPFGC improved significantly compressive strength, splitting tensile strength and chloride penetration resistance. Interestingly, the ratio of compressive strength to splitting tensile strength of HPFGC was lower than that of ordinary concrete, especially for the concrete made with 20 % RHA. Compressive strength and splitting tensile strength of HPFGC containing RHA was similar and slightly higher, respectively, than for HPFGC containing SF. Chloride penetration resistance of HPFGC containing 10-15 % RHA was comparable with that of HPFGC containing 10 % SF.

• Computers and Concrete
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• v.18 no.1
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• pp.113-137
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• 2016

Extensive experimental studies on remarkable mechanical properties Polypropylene Fibre Reinforced Self-compacting Concrete (PFRSCC) have been executed, including different fibre volume fractions of Polypropylene fibers (0.25%, 0.5%, 0.75%, and 1%) and different water to cement ratios (0.21, 0.34, 0.38, and 0.41). The experimental program was carried out by using two hundred and sixteen specimens to obtain the impact resistance and mechanical properties of PFRSCC materials, considering compressive strength, splitting tensile strength, and flexural strength. Statistical and analytical studies have been mainly focused on experimental data to correlate of mechanical properties of PFRSCC materials. Statistical results revealed that compressive, splitting tensile, and flexural strengths as well as impact resistance follow the normal distribution. Moreover, to correlate mechanical properties based on acquired test results, linear and nonlinear equations were developed among mechanical properties and impact resistance of PFRSCC materials.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.112-115
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• 2004

Bond between reinforcing bar and surrounding concrete is supposed to transfer load safely in the process of design of reinforced concrete structures. Bond failure of reinforcing bar generally take place by splitting of the concrete cover as bond force between concrete and reinforcing bars exceeds the confinement of the concrete cover and reinforcement. However, the confinement force has a limitation. Thus, the only variable is the bearing angle corresponding to the change of bond force. Higher rib height bars possessing higher shearing resistance can maintain higher bearing angle and higher splitting resistance when bars are highly confined, and consequently higher bond strength, than lower rib higher bars. In this study, from the evaluate bond strength of high Relative Rib Area Bars Using beam-end test specimens are compared with the current provisions for development of reinforcement, and the improved design method of bond strength is proposed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.36-40
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• 2009

Concrete poles(CP) are popular supports for distribution lines. Various types of grounding electrode, such as copper-clad rods, have been used to maintain CP's ground resistance under the required value. The buried part of CP can also have structural grounding effect because of its iron reinforcing rods inside CPs. In this paper, we measured the total ground current injected into CP ground while measuring the ground current splitting to the metal electrode as well as the total injecting current. By this, it was able to measure the ground current splitting to CP structure. Based on the measured results, interrelationship between ground resistance of metal electrodes and current split factor to CP structure was analyzed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.2
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• pp.131-135
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• 2004

The purpose of this study was to evaluate the resistant force of medial pterygoid muscles against the mandibular advancement and distraction to anterior, and inquire into the relationship between medial pterygoid muscles and cephalometric variables. Sixty six patients with class III malocclusion underwent bilateral sagittal splitting of ramus with intraoralvertico-sagittal ramus osteotomy for mandibular set-back. The spring scale was used to measure the resistance of medial pterygoid muscles after splitting of ramus. Skeletaldental cephalometric analysis was made and statistic package was used for correlation between resistance and cephalometric variables. The resistant force of the right medial pterygoid muscle was greater than the left one in Koreans with class III malocclusion, and the force had a linear regression relationship with facial depth. The results suggested that facial depth has significant correlation with the resistance of medial pterygoid muscle, which can be acquired from patient's cephalometric analysis.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.464-465
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• 2008

Concrete poles(CP) are popular supports for distribution lines. Various types of grounding electrode, such as copper-clad rods, have been used to maintain CP's ground resistance under the required value. The buried part of CP can also have structural grounding effect because of its iron reinforcing rods inside CPs. In this paper, we measured the total ground current injected into CP ground while measuring the ground current splitting to the metal electrode as well as the total injecting current. By this, it was able to measure the ground current splitting to CP structure. Based on the measured results, interrelationship between ground resistance of metal electrodes and current split factor to CP structure was analyzed.

• Membrane Journal
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• v.25 no.2
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• pp.152-161
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• 2015

In this study, novel pore-filled anion-exchange membranes (PFAEMs) with low electrical resistance, high permselectivity, and low water-splitting flux property under a concentration polarization condition have been developed for the enhancement in the efficiency of electrochemical water treatment processes. The base membranes have been prepared by filling a copolymer containing quaternary ammonium groups with an excellent ion-exchange capability into a porous polyolefin substrate, showing a high performance superior to that of a commercial membrane. In addition, it was confirmed that the electrochemical membrane performances are preserved while the water-splitting flux is effectively controlled by coating an imidazolium polymer onto the surface of the base membrane. The prepared PFAEMs revealed remarkably low electrical resistances of about 1/6~1/8 compared to those of a commercial membrane, and simultaneously low water-splitting flux comparable with that of cation-exchange membranes under a concentration polarization condition.

• Journal of the Korean Electrochemical Society
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• v.24 no.2
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• pp.13-27
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• 2021

Stainless steel, which includes Ni and Cr with Fe balance, is most often applied for a wide range of applications such as structure and equipment material. It is not only suitable for use in these applications due to its good corrosion resistance, but also can be applied to catalyst, supporting material, and current collector due to intrinsic properties of Ni and Fe contained in stainless steel. Therefore, in recent years, a lots of surface treatment methods have been studied to activate stainless steel, developing application of water splitting system. In this review paper, the research on the surface treatment technology of stainless steel for water splitting is summarized. It is expected to be able to propose the diverse surface treatment approaches of stainless steel for application to low-cost and highly efficient water splitting electrode.