• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.5
• /
• pp.607-616
• /
• 2022

Corrosion and degradation of reinforced structures due to abnormal climates and natural disasters further accelerate the aging of structures. Coping with the decrease in structure performance, many old structures are being repaired and reinforced with low-weight and high-strength materials such as glass fiber composite material (GFRP). To further contribute, this paper focus on a more economical and eco-friendly material, basalt fiber composite (BFRP), which provide a more effective lateral constraint effect for seismic reinforcement. The main variables considered in this study are the curing temperature during the manufacturing of BFRP and the material characteristics of the target concrete member. The lateral constraint reinforcement effect was investigated through the evaluation of the performance of normal concrete and those with improved durability through fiber reinforcement. The reinforcement effect was 3.15 times for normal concrete and 3.72 times for fiber reinforced concrete, and the difference in reinforcement effect due to the improvement of the durability characteristics of the compression member was not significant. Lastly, the performance of the BFRP was compared with the results of the GFRP reinforcement from the previous study. The effect of the BFRP reinforcement was 1.18 times better than that of the GFRP reinforcement.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.5
• /
• pp.395-409
• /
• 2022

To overcome the limitation of conventional rock excavation methods, the excavation with abrasive waterjet has been actively developed. The abrasive waterjet excavation method has the effect of reducing blasting vibration and enhancing the excavation efficiency by forming a continuous free surface on the rock. However, the waterjet cutting performance varies with rock fracturing characteristics. Thus, it is necessary to analyze the cutting performance for various rocks in order to effectively utilize the waterjet excavation. In this study, cutting experiments with the high pressure waterjet system were performed for basalt and granite specimens. Water pressure, standoff distance, and traverse speed were determined as effective parameters for the abrasive waterjet cutting. The cutting depth and width of basalt specimens were analyzed to compare with granite results. The averaged cutting depth of basalt was shown in 41% deeper than granite; in addition, the averaged cutting width of basalt was formed by 18.5% narrower than granite. The results of this study are expected to be useful basic data for applying rock excavation site with low strength and high porosity such as basalt.

• Korean Chemical Engineering Research
• /
• v.60 no.4
• /
• pp.564-573
• /
• 2022

Calcium carbonate (CaCO₃) exhibits three polymorphs: calcite with arhombohedral, vaterite with a spherical, and aragonite with a needle-like structure. Qualitative and quantitative analyses of the morphology of CaCO₃ are very important to investigate the synthesis of single-crystal vaterite and aragonite. In this work, the polymorphs of calcium carbonate were quantitatively analyzed using XRD. Pure vaterite and pure aragonite were synthesized and the peak distribution of a single phase was analyzed. The vaterite fraction of a mixture of calcite and vaterite was calculated based on the intensity of a specific diffraction peak, and compared to the results based on the peak area. The mean value of f_sV (the correction factor for the peak area of vaterite) was 0.654. The phase analysis of calcite-aragonite mixtures was performed, and the mean value of f_sA (the correction factor for the peak area of aragonite) was obtained as 0.6713. Using these factors, Eq. (24)~Eq. (32) for the quantitative analysis based on the total peak area of XRD were derived to calculate the phase contents of ternary phase CaCO₃. And three-component XRD section was defined considering overlapping sections.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.2
• /
• pp.497-510
• /
• 2021

The purpose of this study is to investigate the mediating effect on intellectual wellness between the physical and emotional wellness of the caregivers of children with disabilities and to provide the relevant data necessary for the response of the caregivers of disabled children. The study subjects were 177 caregivers of children with disabilities, and data were collected from June 2019 to November 2019. Data analysis was performed using the PROCESS macro. Independent sample t-test and one-way batch analyses were conducted to analyze the general characteristics and variables of the collected data. Through this, Scheffé's post-test was performed for variables with statistically significant differences. The relationship between variables was analyzed by Pearson correlation and hierarchical multiple accounting analyses. The results of the study indicate that the physical and intellectual wellness of the main caregivers of children with disabilities provide a direct effect on their emotional wellness as well, and that intellectual wellness provides a mediating effect between physical wellness and emotional wellness. It was found that the influence of the physical environment of children with disabilities is also important, but emotional wellness can be improved only when the main caregivers are provided with an appropriate and sufficient intellectual education. Therefore, the expansion of various educational programs for the main caregivers of children with disabilities could contribute to the improvement of their own overall wellness.

• Journal of Aerospace System Engineering
• /
• v.16 no.3
• /
• pp.23-34
• /
• 2022

Cities around the world are increasing their demand for Urban Air Mobility (UAM) aircraft due to traffic congestion with population concentration. Aircraft with various shapes depending on fixed-wing and propulsion systems, are being prepared for commercialization. Airworthiness certification is required as it is a manned transportation vehicle that flies in the city center and transports people on board. UAM aircraft are vulnerable to lightning and HIRF environments due to the increasing use of composite materials, the use of electric motors, and use of electronic equipment. Currently, the development of certification technology, guidelines, and requirements in lightning and HIRF environments for UAM aircraft is incomplete. In this study, the certification procedures for lightning and HIRF indirect impacts of rotorcraft shown in AC 20-136B and AC 20-158A issued by the Federal Aviation Administration (FAA), were verified and applied to the computerized simulation of UAM aircraft. The impact of lightning and HIRF on ducted fan UAM aircraft was analyzed through computerized simulation, and the basis for establishing practical guidelines for certification of UAM aircraft to be operated in the future is presented.

• Journal of Family Resource Management and Policy Review
• /
• v.27 no.1
• /
• pp.25-39
• /
• 2023

This study aims to analyze the differences in the strength of single-parent families based on family characteristics. Using a sample of 267 female single parents, we explore the factors that impact family strength. We found that several variables impact the strength of families headed by a female single parent: the length of time members had lived together as a single-parent family, co-residents, interactions with ex-spouses, full-time work, and household income. Based on these findings, we suggest that the length of time that single-parent families have lived together is an important criterion for planning and evaluating the family policies and services offered by healthy family support centers. Furthermore, in the context of family resource management, family policies and programs that address time management and family life planning for full-time single parents should be developed and implemented.

• Science of Emotion and Sensibility
• /
• v.26 no.2
• /
• pp.103-116
• /
• 2023

This study aims to investigate the interaction between inward bias and canonical viewpoint, which are factors known to affect preference for meaningful objects. It also considered the familiarity of each entity in terms of their influence on the existence of a canonical viewpoint and demonstrated whether the relative strength of two preferences varies depending on familiarity. To confirm this, we conducted a behavior experiment using a two-alternative forced-choice task. The experimental stimuli were eight single objects for familiarity level (high/low), whereas the entity's inward bias and canonical viewpoint were observed or violated. Results showed that when inward bias was obeyed, the frequency of being chosen as a preferred option was higher, and the reaction time for preference judgment was shorter. However, the observation of a canonical viewpoint did not affect frequency and reaction time. Moreover, familiarity played an interference role in aesthetic judgment. These results indicate that inward bias is stronger than canonical viewpoint, ultimately implying that a single object's interaction with the visual context is superior to the entity's attribute as regards to preference judgment.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.3
• /
• pp.249-258
• /
• 2019

The health care services are the most basic social institutions that are provided to citizen including disabled persons for improvement of health. However, the study of the difference of health care services according to the speech therapy use in the people with speech-language disorders was insufficient. The aim of this investigation was to compare the awareness of health care services and characteristics of people with speech-language disorders according to speech therapy use. The researchers selected 229 people with language disorder using raw data of National Survey of the Disabled Person (2017). We compared the characteristics and health care services of people with speech-language disorders by distinguishing between speech therapy non-users and speech therapy users. Among the 229 people with language disorder, speech therapy users were 37 persons (16.2%). In comparison with non-users, users were younger, more preschoolers, more family incomes, and intellectual disabilities and autistic disorder were the most common types of disability enrollment. Users had a lower proportion of unmet medical needs than non-users. For the reasons of unmet medical need, there were 6.8% and 6.3% of the "economic reasons" and "communication difficulties" Both users and non-users responded that "disability management services" need to be strengthened by the government. In conclusion, we suggest that access to health care services needs to be increased to lower the barriers of speech therapy use.

• The Journal of Korean Academy of Prosthodontics
• /
• v.61 no.2
• /
• pp.125-134
• /
• 2023

When the patient with class III malocclusion needs extensive oral rehabilitation due to multiple missing teeth, accurate diagnosis, and careful analysis, such as the patient's occlusal relationship, facial changes, and evaluation of the temporomandibular joint are essential. Orthognathic surgery is often performed for aesthetic improvement, depending on the patient's chief complaint. If it is not possible due to certain circumstances, partial aesthetic improvement can be achieved through minimal elevation of the vertical dimension. As this patient may have unexpected issues, such as temporomandibular joint disorder, oral habits like bruxism, and masticatory muscle tension, it was determined whether the patient could adjust to a reversible temporary removable partial denture. After this, the maxillary implant-supported fixed prostheses and the mandibular fixed prostheses were used to achieve stable posterior support and to partially improve the maxillary anterior esthetics. The patient was satisfied with the results both aesthetically and functionally. The prognosis is expected to be good if regular check-ups are conducted.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.7 no.11
• /
• pp.447-455
• /
• 2017

At the modern industry, the composite material has been widely used. Particularly, the material of carbon fiber reinforced plastic hardened with resin on the basis of fiber is excellent. As the specific strength and rigidity are also superior, it receives attention as the light material. Among these materials, the carbon fiber reinforced plastic using carbon fiber has the superior mechanical property different from another fiber. So, it is utilized in vehicle and airplane at which high strength and light weight are needed at the same time. In this paper, the tensile property due to the fiber design is investigated through the analysis study with CT specimen composed of carbon plastic reinforced plastic. At the stress analysis of CFRP composite material with hole, the fracture trend at the tensile environment is examined. Also, it is shown that the lowest stress value happens and the deformation energy of the pre-crack becomes lowest at the analysis model composed of the stacking angle of 60° through the result due to the stacking angle. On the basis of this study result, it is thought to apply the foundation data to anticipate the fracture configuration at the structure applied with the practical experiment.