• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.5
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• pp.14-20
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• 2012

In this paper, the flame-retardant wall paper was successfully prepared with recycled polyethylene terephthalate (PET) short cut fiber with flame-retardant property and wood pulp using polyvinyl alcohol (PVA) as binder followed by treatment of non-halogen flame retardant. Physical properties such as formation index, tensile strength, elongation, and burst strength increased as defibrillation increased except tear strength. Bulk increased but formation index, tensile strength, elongation and burst strength decreased along with addition of PET short cut fiber. It was also found that tear strength rose significantly up to 30% of PET short cut fiber and then declined (fell) rapidly. As addition level of PVA increased tensile strength, elongation and burst strength increased, but tear strength decreased slightly. Addition of 20% of PET short cut fiber and 13% of PVA provided the flame-retardant wall paper with both improved flameproofing and physical properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.39-42
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• 2006

Recently, more highly effective construction materials are needed for the reasonable and economical structure system is required as the construction structures become more multi storied, large-sized and diversified. That is to say, the highly qualified concrete, the molt universal construction material is positively promoted as a part of plan to establish the effective space according to the dead load of structures and diminish of segment profile and to build up the economic structures. In particular, it is tendency of that the study for high strength concrete increases and construction example of reinforced concrete (RC) using the high strength concrete partially increases. However, the high strength concrete has the problems such high brittleness and low ductility. Specially, for the high strength concrete, it has different strength from normal concrete as the internal temperature goes up steadily due to high heat of hydration by the quantities of highly level of cement, so the concrete which is mixed with various scible materials is used. This study conducted a basic experiment to conclude an adequate selection of materials and to calculate an optimal mixing proportion of those materials to produce High-strength concrete. And also we conducted an experiment to find out basic properties of this concrete such as slump-flow, strength.

• The Journal of Korean Physical Therapy
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• v.32 no.6
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• pp.335-340
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• 2020

Purpose: This study was performed to investigate the influence of the condition with and without external support on the strength of hip flexor in supine position in subjects without core stabilization. Hip flexor muscles are very functional in the hip joint structures. Therefore, it is essential to evaluate the strength of hip flexor in a clinical and precise way. Methods: Twenty subjects participated in this study. The double bent leg-lower test was used to evaluate subjects without core stabilization. The strength of hip flexor muscles was evaluated in supine position, both with and without external support condition. The paired t-test was used to compare the strength of hip flexor muscles according to external support. The level of statistical significance was at α=0.05. The intra-rater reliability of the repeated measures of hip flexor strength was estimated by calculating the intra-class correlation coefficients (ICC). Results: In subjects without core stabilization, the strength of hip flexor in supine was greater with external support than that without external support (p<0.05). In addition, the intra-rater reliability with an ICC (3, 1) of the strength measurement of hip flexor with external support was higher than that without external support. Conclusion: In subjects without core stabilization, the condition with external support can contribute to the strength of hip flexor in supine position and the strength measurement of hip flexor should be considered with the condition with and without external support.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.683-690
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• 2002

Static and fatigue tests were performed to evaluate fatigue strength in scallop at field bolted joints of longitudinal rib and deck plate in orthotropic steel decks. Numerical parametric studies using finite elemtn analysis were also conducted to show the influence of parameters such as length and radius of scallop, and thickness of deckplate on the stress concentration at the scallop. In the low stress level, fatigue tests yielded cracks at the scallop while in the high stress level, catastrophic failure of longitudinal rib occurred following the failure of handhole cover plate. Fatigue strength was compared with JSSC specification and the predicted S-N curves using Shigley and Juvinall methods, and a satisfactory result was obtatined.

• Journal of Welding and Joining
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• v.13 no.4
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• pp.46-54
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• 1995

The cold cracking susceptibility of a variety of weld metals deposited by GMAW with several kinds of commercial solid wires for high strength-toughness steel was investigated. G-BOP test and LB-TRC test were carried out to study the effects of preheat, chemical composition and hydrogen level on the weld metal cold cracking. The results obtained are as follows. 1) 10% CPT obtained by G-BOP test was the most valuable criteria for evaluating the cold cracking susceptibility of weld metals compared with percentage of cracking at room temperature and crack free temperature, and it had good correlation with the results of LB-TRC test. 2) Cold cracking susceptibility of weld metals was high in the row of MG100A, MG100C, MG100D and MG100B. Welds deposited with MG130 and MG80 showed similar icidents of cracking with MG100C and MG100B respectively, even though their strength levels were different. 3) Diffusible hydrogen level in weld metals which has good relation with hydrogen content in wire itself was the most critical factor for controlling the cold cracking susceptibility of weld metal.

• Steel and Composite Structures
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• v.2 no.5
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• pp.379-396
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• 2002

The paper describes the mechanical behavior of short concrete-filled steel tube (CFT) columns with circular section. The efficiency of the steel tube in confining the concrete core depending on concrete strength and the steel tube thickness was examined. Fifteen columns were tested to failure under concentric axial loading. Furthermore, a mechanical model based on the interaction between the concrete core and the steel tube was developed. The model employs a volumetric strain history for the concrete, characterized by the level of applied confining stress. The situation of passive confinement is accounted for by an incremental procedure, which continuously updates the confining stress. The post-yield behavior of the columns is greatly influenced by the confinement level and is related to the efficiency of the steel tube in confining the concrete core. It is possible to classify the post-yield behavior into three categories: strain softening, perfectly plastic and strain hardening behavior. The softening behavior, which is due to a shear plane failure in the concrete core, was found for some of the CFT columns with high-strength concrete. Nevertheless, with a CFT column, it is possible to use high-strength concrete to obtain higher load resistance and still achieve a good ductile behavior.

• Journal of East-West Nursing Research
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• v.17 no.2
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• pp.164-170
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• 2011

Purpose: The aim of this study was to examine the factors that affect nurses' communication. Methods: This study employed a descriptive survey design. The sample of this study consisted of 174 nurses at hospital in Korea from June 1st to 18th, 2009. The data were analyzed SPSS/WIN 17.0 program and factors affecting nurses' communication were analyzed by multiple regression. Results: 1) Level of nurses' communication was average of 3.44, ego strength 0.36, self-image 3.53, ego distribution 2.92, interpersonal relations 3.52, and family function 3.39. 2) Nurses' communication had significant positive correlation with interpersonal relations, self-image, family function, and ego strength. On the other hand, it had not significant correlation with ego distribution. 3) Interpersonal relations (t=9.68, p<.001), ego strength (t=3.11, p=.002), and family function (t=2.26, p=.025) significantly predicted the level of nurses' communication (Adjusted $R^2$=.418, p<.001). Conclusion: The study finding suggested to develop hospitals' management program for increasing nurses' communication.

• Computers and Concrete
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• v.19 no.5
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• pp.477-488
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• 2017

In this paper, an innovative technique for finite element (FE) modeling of steel tube-confined concrete (STCC) columns with active confinement under axial compressive loading is presented. In this method, a new constitutive model for the stress-strain relationship of actively-confined concrete is proposed. In total, 14 series of experimental STCC stub columns having active confinement were modeled using the ABAQUS software. The results obtained from the 3D model including the compressive strength at the initial peak point and failure point, as well as the axial and lateral stress-strain curves were compared with the experimental results to verify the accuracy of the 3D model. It was found that there existed a good agreement between them. A parametric study was conducted to investigate the effect of the concrete compressive strength, steel tube wall thickness, and pre-stressing level on the behavior of STCC columns with active confinement. The results indicated that increasing the concrete core's compressive strength leads to an increase in the compressive strength of the active composite column as well as its earlier failure. Furthermore, a reduction in the tube external diameter-to-wall thickness ratio affects the axial stress-strain curve and the confining pressure, while increasing the pre-stressing level has a negligible effect on the two.

• Computers and Concrete
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• v.26 no.5
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• pp.385-395
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• 2020

The influence of combination of nano silica and silica fume, as partial cement replacement materials, on the properties of concrete has been studied through the measurement of compressive strength. The compressive strength of concrete in terms of mean, standard deviation and with-in-test coefficient of variation related to the variation in the nominated parameters have also been developed. The compressive strength data developed experimentally has been analyzed using normal-probability distribution and partial safety factors of composite concretes have been evaluated by using first order second moment approach with Hasofer Lind's method. The use of Nano silica and silica fume in concrete decreases the partial safety factor of concrete i.e., increase the reliability of concrete. The experimental results show that the properties of concrete having nano silica and silica fume in combination were better than that of a plain concrete. The SEM test results showing the level of Ca(OH)₂ in plain concrete and consumption level Ca(OH)₂ of concrete containing nano silica & silica fume have also been presented.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.83-87
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• 2002

종강도 위주의 일반 상선의 LMC 의 경우는 단지 선박을 l 차원 Beam Model 로 단순화하여 선미로부터 선수까지의 Weight Distribution 과 Buoyancy Distribution 을 계산하여 두 값의 차이를 Shear Force 로 계산하고 Shear Force 적분값을 Bending Moment 로 계산한다. 횡강도가 중요시되는 Barge 선의 경우 Global Transverse Strength 같은 경우에는 위의 식을 적용할 수 있으나 복수의 바지선을 Hinge Type 이 아닌 Fixed Type 으로 고정시켜 사용할 경우 각각의 Connector 에 작용하는 Strength 값이 횡강도의 큰 비중을 차지한다. 일반적인 Load Master Computer 의 경우 이와 같은 계산이 불가능하며 NAPA 와 같은 전용 계산 프로그램의 경우 하나의 Condition 을 계산하는데 소요되는 시간이 많아 실질적인 Monitoring 은 불가능하다. 이에 특수목적의 Load Master Computer(ShipManager-88) 를 제작하게 되었고 이 Program 을 이용하여 Loadout 과 Floatoff 의 Simulation 을 수행하고 Monitoring 하였다. ShipManager-88 은 Barge 선의 종강도 횡강도, Stability, Trim & Draft 등을 계산하며 Sequence 기능으로 실제 LOADOUT 과 FLOATOFF 시의 모의시뮬레이션을 수행해 볼 수 있으며 Online Interlace 제공으로 Tank 에 설치된 센서에서 Level 값을 받아 실시간으로 현재 선박의 상태를 정확하게 계산할 수 있다. 실제 LOADOUT and FLOATOFF 를 수행하면서 Check 한 부분은 종강도, 횡강모 Stability, Deform, Connector Strength, Level 등을 Check 하였고 종방향의 LOADOUT 이 불가능한 Project 를 위해 Transverse LOADOUT 을 이용할 계획이다.