• New Physics: Sae Mulli
• /
• v.69 no.10
• /
• pp.1107-1114
• /
• 2019

Producing extremely stable high temperature and pressure condition is crucial in order to synthesize novel materials with various functions and to investigate their static and dynamic properties. Already a high pressure in the Mbar range, which is necessary to make novel materials, can be acquired by using a Diamond Anvil Cell (DAC), In this study, a laser-heating system combined with the DAC was designed and installed using two 1064-nm, 100-W fiber lasers on different sides of the DAC to heat the sample and three spectrometers to measure the temperature, pressure, and Raman spectra. A stainless-steel gasket, which is generally used as a sample chamber in high-pressure experiments, was heated to make a thermal radiation source, and the temperature of the heated gasket was obtained by measuring the spectrum of the radiation. By applying this technique, we were able to make various materials and to investigate their physical properties under extreme conditions.

• Safety and Health at Work
• /
• v.15 no.1
• /
• pp.17-23
• /
• 2024

Background: The present study aimed to analyze several aspects of the working conditions and health status of platform workers in the Republic of Korea, such as ergonomic and emotional hazards. We also compared the health status of the platform workers with that of the general population. Methods: A total of 1,000 platform workers participated in this survey from August 7 to August 17, 2022. The participants included 400 designated drivers, 400 food-delivery drivers, and 200 housekeeping managers. A face-to-face survey with a structured questionnaire was conducted by researchers who had received specific instructions. The focus of the survey extended to the work environment, encompassing factors such as workplace violence, as well as physical, chemical, and ergonomic hazards. Health-related data for the previous year were also collected, covering a range of issues such as hearing problems, skin problems, musculoskeletal symptoms, headaches, injuries, mental health issues, and digestive problems. Subsequently, we compared the health symptom data of the responders with those of the general population in the Republic of Korea. Results: Platform workers, including designated drivers, food-delivery drivers, and housekeeping managers, existed in the blind spot of social insurance, facing frequent exposure to physical and chemical hazards, ergonomic risk factors, and direct or indirect violence. The prevalence of health problems, including musculoskeletal symptoms, general fatigue, and depressive symptoms, in each occupational group was statistically higher than that in the general population after standardization for age and gender. Conclusion: The results revealed unfavorable working environment and inferior occupational health of platform workers compared with those of the general population.

• Journal of ILASS-Korea
• /
• v.29 no.3
• /
• pp.105-111
• /
• 2024

Although the classic Kelvin-Helmholtz model of aerodynamically driven jet breakup(primary breakup) has been widely employed in engine CFD codes for the last three decades, the model is not generally predictive. This lack of predictive capability points to the likelihood of an incorrect physical basis for the model formulation. As such, there have been more recent spray-model development efforts that incorporate additional sources of jet instability and breakup, including nozzle-generated turbulence and cavitation but predictive capabilities have remained elusive. Meanwhile, it should be noted that modern combustors increasingly operate under low-temperature combustion(LTC) conditions, where ambient densities and aerodynamic forces are much lower than under classical operating conditions. Therefore, further consideration of physical model formulation is needed. The previous literature introduced a new primary atomization modeling approach premised on experimental measurements by the Faeth group, which demonstrate that breakup is governed by nozzle-generated turbulence under low ambient density conditions. In this new modeling approach, termed the KH-Faeth model, two different primary breakup models are combined to allow the hybrid breakup modeling approach, i.e. Kelvin- Helmholtz instability breakup mechanism and turbulence-induced breakup are competed via dominant breakup rate evaluation. In the current work, we implement this hybrid KH-Faeth model within the open-source CFD framework OpenFOAM and validate the model against detailed drop sizing measurements stemming from collaborative experiments between Georgia Tech and Argonne National Laboratory.

• Physical Therapy Rehabilitation Science
• /
• v.5 no.4
• /
• pp.210-214
• /
• 2016

Objective: The aim of this study was to measure the muscle architectural parameters of abdominal muscles in healthy individuals by rehabilitative ultrasound imaging (RUSI) and to investigate their changes after bridging exercise in various environments. Design: Cross-sectional study. Methods: The study included 40 healthy participants (19 men, 21 women). Subjects were randomly allocated to a stable surface group (SG, n=20) or an unstable surface group (UG, n=20). The participants assumed three positions in rest, bridging exercise with knee flexion $60^{\circ}$, and bridging exercise with knee flexion $90^{\circ}$ for the measurement of abdominal muscle thickness by RUSI. For the resting position, the participants held the head neutral in a hook-lying position and the dominant side was measured. For contraction, the participants performed the bridging exercise with the knee joint in $60^{\circ}$ and $90^{\circ}$ of flexion for 10 seconds each. Results: For transversus abdominis, external oblique muscle thickness, within the stable surface group and the unstable surface group, no significant contraction difference was observed in both the $60^{\circ}$ and $90^{\circ}$ bridge exercise conditions. Contraction difference of internal oblique muscle was significantly larger at $90^{\circ}$ than at $60^{\circ}$ within the SG (p<0.05). But within the UG, no significant contraction difference was shown. There was no significant contraction difference between the surface group and the unstable SG at $60^{\circ}$ condition and at $90^{\circ}$ condition in all measured muscles. Conclusions: The contraction difference is different for each muscle during bridge exercise with knee flexion $60^{\circ}$ and bridging exercise with knee flexion $90^{\circ}$. Muscle contraction difference is generally large when exercised on an unstable surface than a stable surface, but these are not statistically significant when bridging exercise is performed using dynamic air cushion for unstable surface.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.322-322
• /
• 2017

To avoid drought stress under rainfed upland conditions, it is important for rice to efficiently utilize water at shallow soil layers supplied by rainfall, and access to water retained in deer soil layers. The root developmental characteristics of rice, which play important role in the adaptability to drought conditions, vary depending on the variety. Moreover, water availability for plant differs depending on the soil types that have different physical properties such as water holding capacity, permeability, capillary force, penetration resistance, etc. In this study, we evaluated growth and yield responses of rice varieties to various soil water deficit conditions under three different soil types. The experiment was conducted in a plastic greenhouse at the Kenya Agricultural and Livestock Research Organization-Mwea from October 2016 to January 2017. Two upland varieties (NERICA 1 and 4) and one lowland variety (Komboka) were grown in handmade PVC pots (15.2 cm diameter and 85.0 cm height) filled with three different types of soil collected from major rice-growing areas of the country, namely black cotton (BC), red clay (RC), and sandy clay (SC). Three watering methods, 1) supplying water only from the soil surface (W1), 2) supplying water only from the bottom of the pots (W2), and 3) supplying water both from the soil surface and the bottom of pots (W3), were imposed from 40 days after sowing to maturity. Soil water content (SWC) at 20, 40, and 60 cm depths was measured regularly. At the harvesting stage, aboveground and root samples were collected to determine total dry weight (TDW), grain yield, and root length at 0-20, 20-40, 40-60, and 60-80 cm soil layers. Irrespective of the watering methods, the greatest root development was obtained in RC, while that in BC was less than other two soils. In BC, the degree of yield reduction under W1 was less than that in RC and SC, which could be attributed to the higher water holding capacity of BC. In RC, the growth and yield reduction observed in all varieties under W1 was attributed to the severe drought stress. On the other hand, under W2, SWC at the shallow soil depth in RC was maintained because of its higher capillary force compared with BC and SC. As the result, growths and yields in RC were not suppressed under W2. In SC, deep root development was not promoted by W2 irrespective of the varieties, which resulted in significant yield losses. Under W1, the rice growth and yield in SC was decreased although shallow root development was enhanced, and the stomatal conductance was maintained higher than RC. It was suspected that W1 caused nutrients leaching in SC because of its higher permeability. Under rainfed conditions, growth and yield of rice can be strongly affected by soil types because dynamics of soil water conditions change according to soil physical properties.

• Science of Emotion and Sensibility
• /
• v.19 no.3
• /
• pp.3-14
• /
• 2016

This study is aimed to measure the physical colorimetric property according to three conditions, natural dyestuffs (Gardenia, Sappan wood, Lac, Gardenia blue, Mugwort, and Indigo), fabric types (cotton, silk), and presence of mordant (without, with), and then to evaluate the psychological sensibility. Also, to perform analysis of variance (ANOVA) to find out the differences of physical properties according to the three natural dyeing conditions, and to analyze the relationship between physical property and psychological property by Pearson's correlation analysis and then suggest the prediction model by regression analysis using SPSS program (ver. 21.0). Finally, to propose a certain sensibility image map of naturally dyed fabrics, MDS (Multidimensional Scaling) was used, and as a result, Gardenia dyed fabrics having the color sensibilities such as 'hard' and 'heavy' were suggested to evoke masculine image, and to evoke feminine image, Sappan wood and Lac having 'bright', 'transparent', 'soft' and 'light' sensibilities were suggested. Natural image might be induced by using 'subdued' Mugwort dyed fabrics, and active image might be induced by using 'showy' Indigo dyed fabric.

• Research in Community and Public Health Nursing
• /
• v.7 no.2
• /
• pp.183-202
• /
• 1996

This study was designed out to develop a home health care service for nurses working in community care services. This study investigates actual conditions at welfare institutions related to health needs the demands of clients, and the state of home health care services we hope that this study will improve upon the current service system. In Korea home health care services are still developing and only new becoming a part of the health care supply system. The data was collected by recording the client home nursing assessments modified to the situation of UTMB home health agency. In this study 107 clients were selected for home care who needed care for physical and mental deficits. The study lasted from March to November of 1995 at one of the welfare service institutions in Chunchon city. The results show that those who most frequently needed care services were over 50 years old with a health deficit of 80.3%, followed by sex as women who needed care at 59.8%. 50.5% of the clients had very little education. 99.1% of the clients live with their family, and a medical diagnostic analysis reveals that 73.9% of the 5 year period of illnesses were the following : 38.8% - muscular -skeleton system disorder, 24.4% - hypertension and stroke, 25.7% sole disease of arthritis. For behavioral conditions 43.3% of the patients were without care services, 56.6% of the patients were taking treatment that 73.5% of those were taking medication. The most main complaint of patients were 22.4% of pain in the extremities, next were 16.8% of a limitation of body activities, 15.0% was lumbo-sacralgia. According to the investigator who was a senior student nurse, the following suggestions were made: 32.7% for curative medical services, 29.9% for physical exercise, 19.6% for emotional support. Consultation nursing services consisted of 67.2% for physical therapy, 11.2% for the maintaining healing, 9.4% for counseling. The patients at home, required assistance most frequently for muscular-skeleton problems under the category of physical systems (33.3%). But, on the other hand, 49.5% of the patients required care givers at home, 28.2% had a knowledge deficit, 21.0% had malnutrition, 18.4% had bad impaired communication. The character of health problems were devided into chronic disease(67.0%), accidents(I3.1%), and general disease(15.9%). 86% of the disabled client had an impairment of the physical system. Eating (86.9%) , Toileting(77.6%), and personal care showed much the same of ADL condition, the level and range of achievement of mobility, the most frequently self performed was 81.3% only in a room size area, and 40.2% were completely dependent when going out. Although there were a large number of home care services in th community at these welfare institutions, many clients needed a variety of curative services. As policy changes have gathered momentum, responsibility for the development of a more suitable program was demanded by the clients from the community.

• Journal of the Korean Wood Science and Technology
• /
• v.30 no.4
• /
• pp.106-113
• /
• 2002

This research was performed to investigate the effect of moulding conditions on properties of the table top for student desk manufactured by wood waste materials. The table top manufactured using the mat mixed properly with fine particles and coarse particles generally showed better physical properties than those manufactured using either fine particles or coarse particles did/ Especially, highest performance for overlaying was observed when fine particles were used for face layer and coarse particles were used for core layer. The internal bond (IB) strength, the bending strength and thickness swelling increased with the increase of density. Most of physical properties were improved with the increase of hot pressing temperature. The best physical properties were found at 190℃ when the first hot pressing and the second hot pressing times were two minutes. However, the effect of the second hot pressing time of two minutes on the physical properties was not markedly different from that of one minute. This result suggests that the second hot pressing time of one minute is enough to increase the productivity in manufacturing the table top with the least decrease of the physical properties.

• Korean Journal of Childcare and Education
• /
• v.16 no.4
• /
• pp.1-29
• /
• 2020

Objective: The present study aimed to explore the experiences of mothers who have abandoned their additional birth plans since their first child was born. Methods: During in-depth interviews, mothers were asked to recall their own experiences of motherhood. The interview data were analyzed using the grounded theory. Results: The central phenomenon was 'The burden of raising a child is too heavy for mothers to carry alone.' The causal conditions were 'First experience: Unpredictable life', 'Physical and psychological difficulty', and 'Spouse's absence.' The contextual conditions were 'Expectations and reality of parenting' and 'Workplace conditions.' The mothers used interaction strategies of 'Defusing conflict only on a surface level: Giving up', 'Reliance on grandmothers', and 'Downgrading career aspirations.' These strategies were mediated by intervening conditions, 'Stereotypes and experiences of non-family nanny', 'Child's development', and 'Family conflict.' The results were 'Endless guilt', 'Ambivalence between independence versus interdependence' and 'Unfairness: Why only me?' Finally, the process of psychological conflict was identified to account for the steps leading mothers to give up on their birth plans. Conclusion/Implications: During the first experience of motherhood, mothers' conflict gets escalated despite their struggles. These experiences might discourage their additional birth plans. These results provide implications for policies to increase fertility rates.

• Korean Journal of Environmental Biology
• /
• v.23 no.4
• /
• pp.367-373
• /
• 2005

We conducted a year-long survey in 2000 to examine seasonal fluctuations in the abundance of the demersal copepod Pseudodiaptomus sp., the dominant copepod in the Seomjin River estuary, where the spring tide strongly affects changes in salinity gradients. Pseudodiaptomus sp. was found throughout the year in the entire range of salinities measured, but most individuals appeared at oligohaline conditions below 5.0 psu, and less than $2\%$ were observed in polyhaline conditions above 18.0 psu. The peak abundance occurred during autumn in oligohaline waters, and the density was relatively low during the rainy season in summer. In spring and autumn, copepodites were most abundant in oligohaline waters, although they were also fairly abundant in mesohaline conditions $(5\~18\;psu)$. Females with egg sacs appeared in oligo- and mesohaline waters during spring and autumn but were seldom found in polyhaline conditions throughout the year. Our results indicate that, despite the strong physical influence of the tide, Pseudodiaptomus sp. can manipulate its position to remain at its preferred salinity. We also found that spawning mainly occurred in oligohaline waters twice a year.