• 가정과삶의질연구
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• 제27권1호
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• pp.165-179
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• 2009

The purpose of this study is to analyze the effectiveness of a host family experience program on the adaptive behavior and self-management skills of children with severe disabilities and to suggest its applicability into clinical practice. The investigators developed a host family experience program and researched the pre-test and post-test designs with nonequivalent groups. The experiment and comparison groups were comprised of 34 children with severe disabilities that lived at S, a care facility for the severely disabled. They were examined for the program's effects on them before and after the application. After analyzing 17 cases for differences in the subjects' quantitative scores, a qualitative analysis was carried out on one representative case. The quantitative analysis results reveal that the experiment group showed a significant increase in their scores of adaptive behavior and self-management skills compared to the comparison group. Positive changes were also observed among the former group in the qualitative analysis. Thus the host family experience program was effective in improving the adaptive behavior and self-management skills of the children with severe disabilities at the facility. These findings indicate that the host family experience program played a positive role in enhancing the adaptive behavior and self-management skills of the children with severe disabilities at the facility and that such host family experience programs should be applied and reinforced in the field of social welfare practice.

• Steel and Composite Structures
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• 제16권5호
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• pp.491-506
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• 2014

Buckling-restrained braces (BRBs) have excellent hysteretic behavior while buckling-restrained braced frames (BRBFs) are susceptible to residual lateral deformations. To address this drawback, a novel self-centering (SC) BRB with Basalt fiber reinforced polymer (BFRP) composite tendons is presented in this work. The configuration and mechanics of proposed BFRP-SC-BRBs are first discussed. Then an 1840-mm-long BFRP-SC-BRB specimen is fabricated and tested to verify its hysteric and self-centering performance. The tested specimen has an expected flag-shaped hysteresis character, showing a distinct self-centering tendency. During the test, the residual deformation of the specimen is only about 0.6 mm. The gap between anchorage plates and welding ends of bracing tubes performs as expected with the maximum opening value 6 mm when brace is in compression. The OpenSEES software is employed to conduct numerical analysis. Experiment results are used to validate the modeling methodology. Then the proposed numerical model is used to evaluate the influence of initial prestress, tendon diameter and core plate thickness on the performance of BFRP-SC-BRBs. Results show that both the increase of initial prestress and tendon diameters can obviously improve the self-centering effect of BFRP-SC-BRBs. With the increase of core plate thickness, the energy dissipation is improved while the residual deformation is generated when the core plate strength exceeds initial prestress force.

• 한국콘텐츠학회논문지
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• 제15권11호
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• pp.154-164
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• 2015

본 연구의 목적은 진로집단상담프로그램이 보호관찰소 청소년의 진로태도성숙도와 진로결정자기효능감에 어떠한 영향을 미치는가를 검증하고자 하였다. 본 연구결과 진로집단상담프로그램은 보호관찰소 청소년의 진로태도성숙도의 하위 영역 가운데 현실성, 준비성 영역에서는 통계적으로 유의미한 차이를 보였으나, 결정성 영역에서는 유의미한 차이를 보이지 않았다. 또한 진로집단상담프로그램이 보호관찰소 청소년의 진로결정자기효능감 하위 영역 가운데 목표선택, 직업정보, 미래계획 영역에서 통계적으로 유의미한 차이를 보였으나, 문제해결에서는 유의미한 차이를 보이지 않았다. 이와 같은 연구결과는 진로집단상담프로그램이 보호관찰소 청소년의 진로태도성숙도와 진로결정자기효능감에 유의미한 영향을 미치는 것을 증명한 것이다. 앞으로 보호관찰소 청소년의 진로태도성숙도와 진로결정자기효능감의 향상을 위해 더욱더 체계적인 진로집단상담프로그램에 대한 연구가 필요하며 실제로 활용도를 높여 가야 할 것이다.

• Advances in nano research
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• 제15권6호
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• pp.495-511
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• 2023

In this research, the impact of micro-silica, nano-silica, and polypropylene fibers on the fracture energy of self-compacting concrete was thoroughly examined. Enhancing the fracture energy is very important to increase the crack propagation resistance. The study focused on evaluating the self-compacting properties of the concrete through various tests, including J-ring, V-funnel, slump flow, and T50 tests. Additionally, the mechanical properties of the concrete, such as compressive and tensile strengths, modulus of elasticity, and fracture parameters were investigated on hardened specimens after 28 days. The results demonstrated that the incorporation of micro-silica and nano-silica not only decreased the rheological aspects of self-compacting concrete but also significantly enhanced its mechanical properties, particularly the compressive strength. On the other hand, the inclusion of polypropylene fibers had a positive impact on fracture parameters, tensile strength, and flexural strength of the specimens. Utilizing the response surface method, the relationship between micro-silica, nano-silica, and fibers was established. The optimal combination for achieving the highest compressive strength was found to be 5% micro-silica, 0.75% nano-silica, and 0.1% fibers. Furthermore, for obtaining the best mixture with superior tensile strength, flexural strength, modulus of elasticity, and fracture energy, the ideal proportion was determined as 5% micro-silica, 0.75% nano-silica, and 0.15% fibers. Compared to the control mixture, the aforementioned parameters showed significant improvements of 26.3%, 30.3%, 34.3%, and 34.3%, respectively. In order to accurately model the tensile cracking of concrete, the authors used softening curves derived from an inverse algorithm proposed by them. This method allowed for a precise and detailed analysis of the concrete under tensile stress. This study explores the effects of micro-silica, nano-silica, and polypropylene fibers on self-compacting concrete and shows their influences on the fracture energy and various mechanical properties of the concrete. The results offer valuable insights for optimizing the concrete mix to achieve desired strength and performance characteristics.

• Composites Research
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• 제33권5호
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• pp.256-261
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• 2020

본 연구에서는 Al-Ti-C 반응계의 점화온도에 대해 고찰하고, 자전연소합성법 및 교반주조 공정을 통해 TiC/Mg 금속복합재료를 제조하여 미세조직 및 기계적 특성을 분석하였다. 0, 10, 20, 30 vol.% TiC 입자가 균일하게 분산된 Mg 복합재료를 제조하였고, 강화재의 양이 증가할수록 기지 대비 우수한 압축강도 및 내마모특성을 보였다. 이는 in-situ 자전연소합성법에 의해 결함이나 불순물 등의 오염이 적은 TiC/Mg 금속복합재료 제조로 기지에서 강화재로의 효과적인 하중 전달에 의한 것으로 판단된다.

• 보건의료산업학회지
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• 제8권4호
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• pp.109-119
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• 2014

The purpose of this research is to determine oriental hospital staffs' education status, their knowledge, overall attitudes and self-confidence in conducting cardiopulmonary resuscitation (CPR) and how those factors influence their performance of CPR. This research was conducted from September 1st to 15th in 2014 and involved 104 participants who worked at P Oriental Hospital at Y city, and well-structured surveys were used throughout the research. The collected data underwent descriptive statics, t-test, ANOVA, Scheffe' test, Pearson correlation coefficients and stepwise multiple regression by the SPSS WIN 19.0 program. The results revealed the staffs' knowledge of CPR (r=.27, p=.007), attitude (r=.42, p=.001), and confidence in conducting cardiopulmonary resuscitation (r=.48, p=.001), which indicates all the factors are positively correlated. In conclusion, as the knowledge of CPR increased, CPR attitude and CPR performance confidence increased. We also found that a positive attitude toward CPR increases CPR performance confidence. Therefore, education in CPR should be included in workplaces. Through education, CPR performance and performance confidence can be reinforced at the time of emergency.

• Computers and Concrete
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• 제3권4호
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• pp.249-260
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• 2006

Self-consolidating concrete (SCC) in the fresh state is known for its excellent deformability, high resistance to segregation, and use, without applying vibration, in congested reinforced concrete structures characterized by difficult casting conditions. Such a concrete can be obtained by incorporating either mineral or chemical admixtures. This paper presents the results of an investigation to asses the applicability of Abram's law in predicting the compressive strength of SCC to any given age. Abram's law is based on the assumption that the strength of concrete with a specific type of aggregate at given age cured at a prescribed temperature depends primarily on the water-to-cement ratio (W/C). It is doubtful that such W/C law is applicable to concrete mixes with mineral or chemical admixtures as is the case for SCC where water to binder ratio (W/B) is used instead of W/C as the basis for mix design. Strength data of various types of SCC mixtures is collected from different sources to check the performance of Abram's law. An attempt has been made to generalize Abram's law by using various optimization methodologies on collected strength data of various SCC mixtures. A set of generalized equations is developed for the prediction of SCC strength at various ages. The performance of generalized equations is found better than original Abram's equations.

• Steel and Composite Structures
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• 제33권5호
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• pp.641-652
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• 2019

This paper investigates the effect of aftershocks on the seismic performance of self-centering (SC) prestressed concrete frames using the probabilistic seismic demand analysis methodology. For this purpose, a 4-story SC concrete frame and a conventional reinforced concrete (RC) frame are designed and numerically analyzed through nonlinear dynamic analyses based on a set of as-recorded mainshock-aftershock seismic sequences. The peak and residual story drifts are selected as the demand parameters. The probabilistic seismic demand models of the SC and RC frames are compared, and the SC frame is found to have less dispersion of peak and residual story drifts. The results of drift demand hazard analyses reveal that the SC frame experiences lower peak story drift hazards and significantly reduced residual story drift hazards than the RC frame when subjected to the mainshocks only or the mainshock-aftershock sequences, which demonstrates the advantages of the SC frame over the RC frame. For both the SC and RC frames, the influence of as-recorded aftershocks on the drift demand hazards is small. It is shown that artificial aftershocks can produce notably increased drift demand hazards of the RC frame, while the incremental effect of artificial aftershocks on the drift demand hazards of the SC frame is much smaller. It is also found that aftershock polarity does not influence the drift demand hazards of both the SC and RC frames.

• 한국분말재료학회지
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• 제26권5호
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• pp.383-388
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• 2019

To improve the mechanical properties of aluminum, graphene has been used as a reinforcing material, yielding graphene-reinforced aluminum matrix composites (GRAMCs). Dispersion of graphene materials is an important factor that affects the properties of GRAMCs, which are mainly manufactured by mechanical mixing methods such as ball milling. However, the use of only mechanical mixing process is limited to achieve homogeneous dispersion of graphene. To overcome this problem, in this study, we have prepared composite materials by coating aluminum particles with graphene by a self-assembly reaction using poly vinylalcohol and ethylene diamine as coupling agents. The scanning electron microscopy and Fourier-transform infrared spectroscopy results confirm the coating of graphene on the Al surface. Bulk density of the sintered composites by spark plasma sintering achieved a relative density of over 99% up to 0.5 wt.% graphene oxide content.

• Corrosion Science and Technology
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• 제18권3호
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• pp.92-101
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• 2019

This study investigates how rivet head height affects the corrosion performance of carbon fiber reinforced plastic (CFRP) to aluminum alloy self-piercing riveted joints. Specimens with two different head heights were prepared. A rivet head protruding out of the top CFRP laminate forms the proud head height while a rivet head penetrating into the top CFRP generates the flush head height. The salt spray test evaluated corrosion performance. The flush head joints suffered from severe corrosion on the rivet head. Thus, the tensile shear load of flush head joints was substantially reduced. Electrochemical corrosion tests investigated the corrosion mechanisms. The deeper indentation of the flush head height damaged the CFRP around the rivet head. The exposure of damaged fibers from the matrix increased the cathodic potential of local CFRP. The increased potential of damaged CFRP accelerated the galvanic corrosion of the rivet head. After the rivet head coating material corroded, a strong galvanic couple was formed between the rivet head base metal (boron steel) and the damaged CFRP, further accelerating the flush rivet head corrosion. The results of this study suggest that rivet head flushness should be avoided to enhance the corrosion performance of CFRP to aluminum alloy self-piercing riveted joints.