• Steel and Composite Structures
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• v.42 no.6
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• pp.827-841
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• 2022

The rotation capacities of the plastic hinges located at beam-ends are significantly reduced in traditional steel framed-tube structures (SFTSs) because of the small span-to-depth ratios of the deep beams, leading to the low ductility and energy dissipation capacities of the SFTSs. High-strength steel framed-tube structures with replaceable shear links (HSSFTS-RSLs) are proposed to address this issue. A replaceable shear link is located at the mid-span of a deep spandrel beam to act as a ductile fuse to dissipate the seismic energy in HSSFTS-RSLs. A 2/3-scaled HSSFTS-RSL specimen with a shear link fabricated of high-strength low-alloy Q355 structural steel was created, and a cyclic loading test was performed to study the hysteresis behaviors of this specimen. The test results were compared to the specimens with soft steel shear links in previous studies to investigate the feasibility of using high-strength low-alloy steel for shear links in HSSFTS-RSLs. The effects of link web stiffener spaces on the cyclic performance of the HSSFTS-RSLs with Q355 steel shear links were investigated based on the nonlinear numerical analysis. The test results indicate that the specimen with a Q355 steel shear link exhibited a reliable and stable seismic performance. If the maximum interstory drift of HSSFTS-RSL is designed lower than 2% under earthquakes, the HSSFTS-RSLs with Q355 steel shear links can have similar seismic performance to the structures with soft steel shear links, even though these shear links have similar shear and flexural strength. For the Q355 steel shear links with web height-to-thickness ratios higher than 30.7 in HSSFTS-RSLs, it is suggested that the maximum intermediate web stiffener space is decreased by 15% from the allowable space for the shear link in AISC341-16 due to the analytical results.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3260-3267
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• 2023

Zr-Nb alloy have been widely used as fuel rods in nuclear power plants. However, from the Fukushima nuclear accident, the weakness of the rod was revealed under harsh conditions, and research on the safety of these types of rods was conducted after the disaster. The method of depositing chromium onto the existing Zr-Nb alloy fuel rods is being considered as a means by which to compensate for the weakness of Zr-Nb alloy rods because chromium is strong against oxidation at high temperatures and has high strength. In order to secure these advantages, it is important to maintain the Cr thickness of the rods and properly inspect the rods before and during their use in power generation. Eddy current testing is a typical means of evaluating the thickness of thin metals and detecting surface defects. Depending on the size and shape of the inspected object, various eddy current sensors can be applied. In particular, because pancake sensors can be manufactured in very small sizes, they can be used for inspections even in narrow spaces, such as a nuclear fuel assembly. In this study, an eddy current technique was developed to confirm the feasibility of Cr coating thickness evaluations. After determining the design parameters of the pancake sensor by means of a FEM simulation, a FPCB pancake sensor was manufactured and the optimal frequency was selected by measuring minute changes in the Cr-coating thickness using the developed sensor.

• Journal of Wellbeing Management and Applied Psychology
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• v.5 no.4
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• pp.19-31
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• 2022

Purpose: This study was conducted to identify indoor air quality in various living spaces using sensors that can measure noise, vibration, fine dust, and odor in real time and to propose optimal indoor air quality maintenance management using Internet of Things(IoT). Research design, data and methodology: Using real-time sensors to monitor physical factors and environmental air pollutants that affect the comfort of the residential environment, Noise, Vibration, Atmospheric Pressure, Blue Light, Formaldehyde, Hydrogen Sulfide, Illumination, Temperature, Ozone, PM10, Aldehyde, Amine, LVOCs and TVOCs were measured. It were measured every 1 seconds from 4 offices and 4 stores on a small scale from November 2018 to January 2019. Results: The difference between illuminance and blue light for each measuring point was found to depend on lighting time, and the ratio of blue light in total illumination was 0.358 ~ 0.393. Formaldehyde and hydrogen sulphide were found to be higher than those that temporarily attract people in an indoor office space that is constantly active, requiring office air ventilation. The noise was found to be 50dB higher than the office WHO recommendation noise level of 35 ~ 40dB. The most important factors for indoor environmental quality were temperature> humidity> illumination> blue light in turn. Conclusions: Various factors that determine the comfort of indoor living space can be measured with real-time sensors. Further, it is judged that the use of IoT can help maintain indoor air quality comfortably.

• Journal of Korean Society of Rural Planning
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• v.29 no.4
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• pp.13-26
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• 2023

Recently, South Korea has prepared laws and systems to systematically manage rural spaces in response to the era of population decline and is making various efforts to promote related policies. However, various basic studies that can support this are still insufficient. In particular, in this study, the functions and roles of each settlement class were established along with the classification of the sedentary classes in rural areas, and the classification system for rural living services was established, and the hierarchy by functional facilities and the minimum standards for vulnerable areas (accessibility) were established. Specifically, in this study, the settlement class was divided into 4 classes of "central area - midpoint area - small point area - hinterland", and each function and role was presented, and the rural living service classification system was finally reestablished as 10 sectors and 31 functional facilities. In addition, the hierarchy and accessibility standards of rural living service functional facilities was set within 5 to 15 minutes for 'lower and basic services', within 10 to 20 minutes for 'medium and basic services', within 15 to 30 minutes for 'intermediate and complex services', within 20 to 60 minutes for 'high car/complex service' and within 10 minutes for 'urgent service'.

• Tribology and Lubricants
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• v.39 no.5
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• pp.197-202
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• 2023

Recently, research on experimental and analytical techniques utilizing microfluidic devices has been pursued. For example, lab-on-a-chip devices that integrate micro-devices onto a single chip for processing small sample quantities have gained significant attention. However, during sample preparation, unnecessary gases can be introduced into the internal channels, thus, impeding device flow and compromising specific function efficiency, including that of analysis and separation. Several methods have been proposed to mitigate this issue, however, many involve cumbersome procedures or suffer from complexities owing to intricate structures. Recently, some approaches have been introduced that utilize hydrophobic device structures to remove gases within channels. In such cases, the permeability of gases passing through the structure becomes a crucial performance factor. In this study, a method involving the deposition and sintering of diluted Ag-ink onto a silicon wafer surface is presented. This is followed by unstructured nano-pattern creation using a Metal Assisted Chemical Etching (MACE) process, which yields a nanostructured surface with unstructured pillar shapes. Subsequently, gas permeability in the spaces formed by these surface structures is investigated. This is achieved by experiments conducted to incorporate a pressure chamber and measure gas permeability. Trends are subsequently analyzed by comparing the results with existing theories. Finally, it can be confirmed that the significance of this study primarily lies in its capability to effectively evaluate gas permeability through unstructured pillar-like nanostructures, thus, providing quantitative values for the appropriate driving pressure and expected gas removal time in practical device operation.

• Journal of Veterinary Clinics
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• v.41 no.2
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• pp.101-105
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• 2024

Ehlers-Danlos syndrome (EDS) is a rare genetic disorder in dogs and cats and has been mostly reported in purebred cats. In this study, we report a case of a 1-year-old castrated male Korean shorthair cat, who presented with multiple small skin tears and bruises distributed over the entire trunk area. The cat's skin was hyperextensible and easily torn with gentle touch. The skin extensibility index of the cat was 25%, indicating the possibility of EDS. The cat exhibited no signs of pruritus or inflammation, and no underlying disease was found. However, radiography revealed hip joint subluxation and arthritis. Following this, biopsy of the lacerated skin was performed. Histopathological examination of the skin revealed that in the dermis adjacent to the lesions, the collagen fibers were irregular in size and width, with a slightly thinner epidermis, and increased interfibrillar spaces containing low numbers of scattered well-differentiated fibroblasts and mast cells. Histopathological examination of the skin confirmed EDS. The symptoms observed in the cat, including skin hyperextensibility, multiple bruising, hip joint subluxation, and arthritis, corresponded to the classical subtype of EDS in humans. Thus, this study is a rare report of a classical EDS case in a Korean shorthair cat. This study suggests that skin extensibility index and biopsy are useful diagnostic procedures for confirming EDS in animals until a more definitive genetic test is established.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.209-214
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• 2024

The purpose of this study is to analyze the spatial structure of laboring classes in Manchester in the 19th century. Manchester had districts where laboring classes lived in destitution. Elizabeth Gaskell's Mary Barton demonstrates the miserable state of laboring classes by depicting their small, dirty living residential spaces. Engels's The Condition of the Working Class in England analyzes the laboring classes in industrial areas in England, especially Manchester. The laboring classes' districts formed in a set pattern were separated from the area for bourgeois. It lied in the old district near commercial areas, while upper classes were outside areas. It was the dominant ideology that drove the transformation of Manchester as an industrial city characterized by separation.

• Safety and Health at Work
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• v.15 no.3
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• pp.284-291
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• 2024

Background: This study aimed to identify the prevalence of workplace hazards and organizational protection resources according to the size of the enterprise in the manufacturing industry of the Republic of Korea. Methods: We analyzed data of waged workers (weighted N = 5,879) from the Fifth Korean Working Conditions Survey (2017). Enterprise sizes were categorized as "micro enterprises" (less than five employees), "small enterprises" (5-49 employees) and "medium-large enterprises" (50 or more employees). Self-reported exposure to 18 physical, chemical, ergonomic, and psychological hazards were measured. The presence of organizational protection resources such as a labor union, a safety delegate working at the company, designated spaces to deal with safety, and the provision of health and safety information was evaluated. Results: Compared to workers in medium-large enterprises, those in micro enterprises showed a higher proportion of exposure to most of physical, chemical, ergonomic, and psychological hazards, except for exposure to solvents, prolonged sitting, and experiencing a state of emotional unrest. On the other hand, workers in micro enterprises had the lowest proportion of access to organizational protection resources. Conclusion: Our study demonstrates that manufacturing workers at the micro enterprise in the Republic of Korea are exposed to the most hazardous work environment and yet have access to the fewest organizational protection resources.

• Asian Journal of Turfgrass Science
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• v.21 no.1
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• pp.9-21
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• 2007

Research was initiated to examine establishment efficiency of zoysiagrass by plugging. Zoysiagrass is known to be a slowly establishing turfgrass species. Properly-treated zoysiagrass seed can speed up the establishment rate, while initial irrigation practice is intensively required after seeding. A planting method with small plugs($2.5{\times}2.5cm$) from seeding can overcome initial watering requirement. Establishment speed, however, can vary with planting dates, planting spaces, and plastic film cover in early stage. Establishment characteristics were investigated for two years by planting dates that were April 5, May 18, July 13, August 24 and October 29 in 2004 and April 6 in 2005. They were also compared with three different spaces($20{\times}20,\;25{\times}25,\;and\;30{\times}30cm$) and three different fertilizer levels(15, 30, and $45g\;N{\cdot}m^{-2}$). Ground coverage reached to 90% in plugs of 'Zenith' zoysiagrass planted on April 5. It increased suddenly in period of July to August, resulting in about 50% of full establishment rate. Establishment rates were significantly faster over 9% in plugs spaced at $20{\times}25cm$ than in those at $30{\times}30cm$. No significant differences were observed on the stolen number and stolen length in the study. Survival rate in zoysiagrass plug was over 90% at all plantings. These results demonstrated that zoysiagrass establishment using small plug from seeding is considered to be a safe and efficient method.

• Korean Journal of Environment and Ecology
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• v.30 no.3
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• pp.344-352
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• 2016

The goal of this study was to identify the water temperature and sound environment of oviposition sites of the Huanren brown frog (Rana huanrensis), which breeds in valleys in early spring. The study was conducted in Chiak National Park, central Korea, between March 23 and April 24, 2015. Correlation analysis of the physical factors of oviposition sites revealed that the number of egg clutches was positively correlated (p < 0.05) with the water temperature and negatively correlated (p < 0.05) with the sound volume of the oviposition sites. However, no correlation was found between clutch number and the total area or depth of water. The water temperature of the oviposition sites was $2.2^{\circ}C$ higher on average than that of the mainstream (p < 0.001). To avoid the low early spring temperatures, R. huanrensis spawned in sites with accumulated water, in which the depths were less than 10cm and the temperature was relatively high. Further, eggs were spawned in clusters in small spaces to maximize the thermal insulation effect. In terms of noise levels, oviposition sites were found to be 6.9 dB quieter than the mainstream (p<0.001). In conclusion, R. huanrensis was found to spawn in warm, quiet, and small oviposition sites in valleys to avoid low early spring temperatures and loud water noise. This study is significant because it is the first to characterize the sound environment of amphibian oviposition sites.