• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.96-102
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• 2022

Reactants of PEMFC are hydrogen and oxygen in gas phases and fuel cell overpotential could be reduced when reactants are smoothly transported. Numerous studies to modify cathode flow field design have been conducted because oxygen mass transfer in high current density region is dominant voltage loss factor. Among those cathode flow field designs, a block in flow field is used to forced supply reactant gas to porous gas diffusion layer. In this study, the block was installed on a simple fuel cell model. Using computational fluid dynamics (CFD), effects of forced convection due to blocks on a polarization curve and local current density contour were studied when different air flow rates were supplied. The high current density could be achieved even with low air supply rate due to forced convection to a gas diffusion layer and also with multiple blocks in series compared to a single block due to an increase of forced convection effect.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1676-1685
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• 2021

We develop a new high-fidelity multiphysics model to simulate boron chemistry in the porous Chalk River Unidentified Deposit (CRUD) deposits. Heat transfer, capillary flow, solute transport, and chemical reactions are fully coupled. The evaporation of coolant in the deposits is included in governing equations modified by the volume-averaged assumption of wick boiling. The axial offset anomaly (AOA) of the Seabrook nuclear power plant is simulated. The new model reasonably predicts the distributions of temperature, pressure, velocity, volumetric boiling heat density, and chemical concentrations. In the thicker CRUD regions, 60% of the total heat is removed by evaporative heat transfer, causing boron species accumulation. The new model successfully shows the quantitative effect of coolant evaporation on the local distributions of boron. The total amount of boron in the CRUD layer increases by a factor of 1.21 when an evaporation-driven increase of soluble and precipitated boron concentrations is reflected. In addition, the concentrations of B(OH)₃ and LiBO₂ are estimated according to various conditions such as different CRUD thickness and porosity. At the end of the cycle in the AOA case, the total mass of boron incorporated in CRUD deposits of a reference single fuel rod is estimated to be about 0.5 mg.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.3
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• pp.210-214
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• 2022

Objective: Platelet-rich plasma (PRP) therapy has received a considerable attention as an adjunct to fertility treatments, especially in women with very low ovarian reserve and premature ovarian insufficiency. Although recent studies have demonstrated that PRP led to improvements in folliculogenesis and biomarkers of ovarian reserve, the effect of intraovarian PRP administration on embryo genetics has not been studied. Methods: We report a pilot study of patients who had preimplantation genetic testing for aneuploidy (PGT-A) before and then within 3 months following PRP administration. Twelve infertile women with at least one prior failed in vitro fertilization (IVF) cycle underwent ovarian stimulation (cycle 1) with a gentle stimulation protocol and PGT-A performed at the blastocyst stage. Following cycle 1, autologous intraovarian PRP administration was performed. Within 3 months following PRP administration, the patients underwent cycle 2 and produced blastocysts for PGT-A. The percentage of euploid embryos between both cycles was compared. Results: The mean age of all participants was 40.08±1.46 years, and their mean body mass index was 26.18±1.18 kg/m². The number of good-quality embryos formed at the blastocyst stage was similar between cycle 1 and cycle 2 (3.08±0.88 vs. 2.17±0.49, respectively; p=0.11). Among all patients in cycle 1, 3 of 37 embryos were euploid (8.11%) while in cycle 2, 11 out of 28 embryos were euploid (39.28%, p=0.002). Three clinical pregnancies were noted among this patient group. Conclusion: This novel study is the first to present an improvement in the embryo euploidy rate following intraovarian PRP application in infertile women with prior failed IVF cycles. The growth factors present in PRP may exhibit a local paracrine effect that could improve meiotic aberrations in human oocytes and thus improve euploidy rates. Whether PRP improves live birth rates and lowers miscarriage rates remains to be determined in large trials.

• Wind and Structures
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• v.34 no.2
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• pp.185-197
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• 2022

This study aimed to analyze the wind-induced mechanical energy (WME) of a proposed super high-rise and long-span transmission tower-line system (SHLTTS), which, in 2021, is the tallest tower-line system with the longest span. Anew index - the WME, accounting for the wind-induced vibration behavior of the whole system rather than the local part, was first proposed. The occurrence of the maximum WME for a transmission tower, with or without conductors, under synoptic winds, was analyzed, and the corresponding formulae were derived based on stochastic vibration theory. Some calculation data, such as the drag coefficient, dynamic parameters, windshielding areas, mass, calculation point coordinates, mode shape and influence function, derived from wind tunnel testing on reducedscale models and finite element software were used in calculating the maximum WME of the transmission tower under three cases. Then, the influence of conductors, wind speed, gradient wind height and wind yaw angle on WME components and the energy transfer relationship between substructures (transmission tower and conductor) were analyzed. The study showed that the presence of conductors increases the WME of transmission towers and changes the proportion of the mean component (MC), background component (BC) and resonant component (RC) for WME; The RC of WME is more susceptible to the wind speed change. Affected by the gradient wind height, the WME components decrease. With the RC decreasing the fastest and the MC decreasing the slowest; The WME reaches the its maximum value at the wind yaw angle of 30°. Due to the influence of three factors, namely: the long span of the conductors, the gradient wind height and the complex geometrical profile, it is important that the tower-line coupling effect, the potential for fatigue damage and the most unfavorable wind yaw angle should be given particular attention in the wind-resistant design of SHLTTSs

• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.87-95
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• 2023

On October 29, 2022, a very large number of people gathered in Itaewondong, Yongsan-gu, Seoul, Korea for a Halloween festival, and as crowds pushed through narrow alleys, 159 deaths and 195 injuries occurred, making it the largest crushing incident in Korea. There have been a number of stampede deaths where crowds gathered at large-scale festivals, event venues, and stadiums, both at home and abroad. When the density increases, the physical contact between bodies becomes very strong, and crowd turbulence occurs when the force of the crowd is suddenly added from one body to another; thus, the force is amplified and causes the crowd to behave like a mass of fluid. When crowd turbulence occurs, people cannot control themselves and are pushed into he crowd. To prevent a stampede accident, investigation and management of areas expected to be crowded and congested must be systematically conducted, and related ministries and local governments are planning to establish a crowd management system to prepare safety management measures to prevent accidents involving multiple crowds. In this study, based on national data, a continuous digital topographic map is modeled in 3D to analyze the risk of crowding and present a plan for selecting high-risk walking routes. Areas with a high risk of crowding are selected in advance based on various data (numerical data, floating population, and regional data) in a realistic and feasible way, and the analysis is based on the visible results from 3D modeling of the risk area. The study demonstrates that it is possible to prepare measures to prevent cluster accidents that can reflect the characteristics of the region.

• Archives of Craniofacial Surgery
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• v.24 no.4
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• pp.189-192
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• 2023

An intraosseous hemangioma of the frontal bone is typically removed via a coronal incision. This procedure, while effective, can be lengthy and may result in complications such as a prominent scar and hair loss. An alternative approach involves a direct incision in the forehead, which leaves a less noticeable scar and allows a quicker recovery. However, in this specific case, the patient declined both coronal surgery and surgery through a direct forehead incision due to cosmetic concerns. Therefore, we proposed an anterior hairline incision. A 35-year-old woman presented with a firm, non-mobile, palpable mass on her right forehead. Preoperative non-contrast computed tomography revealed a heterogeneous osteolytic lesion. We performed an excisional biopsy through the anterior hairline. Postoperative non-contrast computed tomography was conducted 2 and 6 months after surgery. The wound was clean and free of complications, and there was no local recurrence. Partial resection can reduce scarring for patients who are concerned about cosmetic outcomes. However, the potential for recurrence remains a significant concern. We present this case of an anterior hairline incision for a hemangioma located in the forehead, evaluated using serial computed tomography for both preoperative and postoperative imaging.

• Parasites, Hosts and Diseases
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• v.61 no.2
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• pp.216-224
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• 2023

In several schistosomiasis-endemic countries, the prevalence has remained high in some areas owing to reinfection despite repeated mass drug administration (MDA) interventions; these areas are referred to as persistent hot spots. Identifying hotspots is critical for interrupting transmission. This study aimed to determine an effective means of identifying persistent hot spots. First, we investigated the differences between Schistosoma haematobium and Schistosoma mansoni prevalence among school-aged children (SAC) estimated by a community-based survey, for which local key informants purposively selected communities, and a randomly sampled school-based survey. A total of 6,225 individuals residing in 60 villages in 8 districts of North Kordofan, Blue Nile, or Sennar States, Sudan participated in a community-based survey in March 2018. Additionally, the data of 3,959 students attending 71 schools in the same 8 districts were extracted from a nationwide school-based survey conducted in January 2017. The community-based survey identified 3 districts wherein the prevalence of S. haematobium or S. mansoni infection among SAC was significantly higher than that determined by the randomly sampled school survey (e.g., S. haematobium in the Sennar district: 10.8% vs. 1.1%, P<0.001). At the state level, the prevalence of schistosomiasis among SAC, as determined by the community-based survey, was consistently significantly higher than that determined by the school-based survey. Purposeful selection of villages or schools based on a history of MDA, latrine coverage, open defecation, and the prevalence of bloody urine improved the ability for identifying persistent hot spots.

• Journal of Environmental Health Sciences
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• v.48 no.1
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• pp.52-58
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• 2022

Background: Few studies have evaluated the exposure to phthalates via inhalation of floor dust in children's living areas. Objectives: This study evaluated the concentration and exposure level of phthalates emitted from indoor floor dust in children's living areas. Methods: This study utilized the results of a survey conducted by the Ministry of Environment in 2019. Indoor dust was collected from 150 households with children aged 3~7 and 67 daycare centers or local children's centers by using vacuum cleaners. It was analyzed by gas chromatography mass spectrometry. Six types of phthalates were analyzed: Bis (2-ethylhexyl) phthalate (DEHP), Dibutyl phthalate (DBP), Benzyl butyl phthalate (BBP), Di-N-octyl phthalate (DNOP), Diisononyl phthalate (DINP), Di -isodecyl phthalate (DIDP). Results: The medians of DEHP concentrations were 1,028 and 1,937 mg/kg in homes and daycare centers, respectively. The median and maximum values of daily intake were calculated by applying the median and 95th percentile values (the upper 5% of the total concentration) in dust measured in the homes. The DEHP median value was 1.6 ㎍/kg/bw/day, and a maximum A value of 7.8 ㎍/kg/bw/day was calculated. When the childcare center values were applied, the median daily intake of DEHP was 3.1 ㎍/kg/bw/day and the maximum value was 29.2 ㎍/kg/bw/day. As a result of calculating the daily intake by integrating the values of home and childcare facilities, the median and maximum values of daily intake were 1.9 and 10.9 ㎍/kg/bw/day, respectively. Conclusions: This study derives phthalate concentrations among the floor dust in homes and childcare facilities where children mainly spend time, and suggests their intake of phthalates through this. In particular, it was newly suggested that the phthalate concentrations in homes and childcare facilities are different, resulting in differences in intake.

• Journal of the Korean Society of Food Culture
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• v.23 no.6
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• pp.693-704
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• 2008

In this study, the preference for Korean Kimchi by Chinese people in Shandong Province was evaluated. Specifically, this study was conducted to aid in the introduction of Kimchi to China by providing information and developing local types designed to meet regional taste preferences. The subjects were comprised of 298 Chinese (male 108, female 190) residents of Weihai, Yantai and Qingdao, in Shandong province, China. The subjects were provided with a self administered questionnaire form designed to evaluate their views on Korean Kimchi. The collected data were then analyzed using the SAS software package. The results revealed that 95.3% of the respondents were aware of Korean Kimchi. In addition, 100% of the respondents who had visited Korea and 98.1% of the respondents who had an interest in Korea were aware of Kimchi. With regard to the origins of their interest in Kimchi, 26.8% of the subjects answered 'through mass media', while 23.9% reported that they learned about Kimchi 'through friends'. Most subjects recognized Kimchi as a 'Korean traditional food' (92.6%), a 'delicious food' (53.2%), and a 'fermented food' (38.0%). Baechu Kimchi was found to be the most well-known Kimchi, followed by Kkakdugi, Oi Kimchi, Yoelmu Kimchi and Nabak Kimchi. Additionally, 69.1% of the subjects knew how it was prepared, most of whom reported that they learned how Kimchi was prepared through 'Korean movie and/or drama'. Moreover, 88.9% of the subjects had eaten Kimchi. Overall, 43.8% of the subjects reported that they ate Kimchi $1{\sim}2$ times per month, while 32.1% reported that they ate Kimchi $1{\sim}2$ time per year. The most common places that Kimchi was eaten were a 'Korean restaurant' (67.6%) or with a 'colleague' (32.8%). The primary reasons for not having eaten Kimchi were 'no knowledge or dislike of Kimchi by family' (30.3%), 'difficulty purchasing Kimchi' (21.2%), 'high priced Kimchi' (21.2%), and 'dislike the smell and shape of Kimchi' (12.1%).

• Journal of the Daesoon Academy of Sciences
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• v.18
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• pp.149-164
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• 2004

Various social surveys conducted by mass media and government agencies in recent years in Japan suggest that the percentage of those who believe in religion are between twenty and thirty percent. However, more than seventy percent of Japanese visit Shinto shrines or Buddhist temples during the New year period. Although there are varying interpretations on whether Japanese people are religious or not, detailed research shows the existence of certain religious tendencies among Japanese. I base my estimates on research surveys of college students covering a period of almost ten years. It is helpful for understanding the religiosity of the Japanese to differentiate between "clear-cut religion" and "peripheral religious phenomena." The exact boundary between these two categories, however, is difficult to clearly demarcate. "Clear-cut religion" refers here phenomena which are directly related to established religious organizations such as shrine Shinto, Buddhist sects, or Christianity. "Peripheral religious phenomena" covers such phenomena as fortune telling, mystical phenomena, religious customs and similar matters. It is often said that the younger generations are less concerned with religion. Our seven surveys questioning several thousand college students, conducted between 1995 and 2001, show that only between six and seven percent of the students state that they believe in religion. Additionally, the extent of negative attitudes toward religion quite remarkable. On the other hand, students who take part in conventional ritual such as a New year's visit to a shrine or temple and visiting the graves of ancestors amount to about fifty percentage. In spite of the prevailing negative attitude toward religious groups, these students have apparently kept a certain level of interest in religious customs. Moreover, they show a relatively strong interest in fortune telling, mystical phenomena, or supernatural phenomena. The exact degree of a positive attitude toward peripheral religious phenomena differs according to the level of being informed on these matters. As a whole, they largely rely on information gained from their families and local communities. Therefore, we can conclude that there is a degree of transmission of religious culture among younger generations.