• Title/Summary/Keyword: Mass changes

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Numerical Analysis of the Sessile Droplet Evaporation on Heated Surfaces (가열된 표면에 고착된 액적의 증발 특성에 관한 수치해석 연구)

  • Jeong, Chan Ho;Lee, Hyung Ju;Yun, Kuk Hyun;Lee, Seong Hyuk
    • Journal of ILASS-Korea
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    • v.26 no.1
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    • pp.1-8
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    • 2021
  • Droplet evaporation has been known as a common phenomenon in daily life, and it has been widely used for many applications. In particular, the influence of the different heated substrates on evaporation flux and flow characteristics is essential in understanding heat and mass transfer of evaporating droplets. This study aims to simulate the droplet evaporation process by considering variation of thermal property depending on the substrates and the surface temperature. The commercial program of ANSYS Fluent (V.17.2) is used for simulating the conjugated heat transfer in the solid-liquid-vapor domains. Moreover, we adopt the diffusion-limited model to predict the evaporation flux on the different heated substrates. It is found that the evaporation rate significantly changes with the increase in substrate temperature. The evaporation rate substantially varies with different substrates because of variation of thermal property. Also, the droplet evaporates more rapidly as the surface temperature increases owing to an increase in saturation vapor pressure as well as the free convection effect caused by the density gradient.

Changes in eating habits and lifestyle during COVID-19 curfew in children in Saudi Arabia

  • Hanbazaza, Mahitab;Wazzan, Huda
    • Nutrition Research and Practice
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    • v.15 no.sup1
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    • pp.41-52
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    • 2021
  • BACKGROUND/OBJECTIVES: Curfew due to the coronavirus disease 2019 (COVID-19) pandemic could influence health behaviors in people, especially in children, who can easily acquire unhealthy eating habits. This study aimed to investigate the effect of COVID-19 on weight, health behaviors including eating habits, physical activity, and sedentary behavior in children aged 6-15 years in Saudi Arabia. SUBJECTS/METHODS: We conducted a cross-sectional online survey that included 280 children aged 6-15 years in Saudi Arabia during the COVID-19 curfew. The survey included questions on sociodemographic characteristics, anthropometric measures, and health behaviors including eating habits, physical activity, and sedentary behavior. RESULTS: We observed a significant difference in the body mass index before and after the COVID-19 pandemic (P < 0.001). Children significantly tended to skip breakfast, along with a decreased intake of dairy products and fast food (P < 0.001). Moreover, children were less physically active and significantly tended to be involved in leisure screen-based activities, including watching TV and use of computer/games (P < 0.001). CONCLUSIONS: This study provides evidence for the negative influences of the COVID-19 curfew on health behaviors, including eating habits, physical activity, and sedentary behavior in children in Saudi Arabia.

A Case Report of Taeeumin Patient with Diabetes Treated with Yeoldahansotang-Gamibang (태음인 당뇨 환자의 열다한소탕가미방 치험 1례)

  • Han, Suzy;Ahn, Da-Young;Yu, Jun-Sang
    • Journal of Sasang Constitutional Medicine
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    • v.34 no.2
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    • pp.75-83
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    • 2022
  • Objectives The aim of this study is to report the improvement in Taeeumin's dryness-heat symptom of a 54-year-old man diagnosed with type-II diabetes mellitus after treated by herbal medicine. Methods The Taeeumin patient took Yuldahansotang-gamibang for 9 months to manage Taeeumin's dryness-heat symptom. We examined the changes of Body Mass Index(BMI), Fating Blood Sugar(FBS), Hemoglobin A1c(HbA1c), and ketouria. Results Type-II diabetes mellitus symptoms in the patient with Taeeumin's dryness-heat symptom were thirst, fatigue, and increased body weight. All numerical levels for blood sugar, HbA1c, and ketouria were reduced after taking Yuldahansotang-gamibang. Conclusions The treatment of the patient with Taeeumin's dryness-heat symptom and type-II diabetes mellitus with Yuldahansotang-gamibang was efficient, and further research is needed to prove the effect of Yuldahansotang-gamibang for treating such patients.

Analysis of colliding index on impact behavior of RC columns under repeated impact loading

  • Tantrapongsaton, Warakorn;Hansapinyo, Chayanon;Wongmatar, Piyapong;Limkatanyu, Suchart;Zhang, Hexin;Charatpangoon, Bhuddarak
    • Computers and Concrete
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    • v.30 no.1
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    • pp.19-32
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    • 2022
  • This paper presents an investigation into the failure of RC columns under impact loadings. A numerical simulation of 19 identical RC columns subjected to single and repeated impact loadings was performed. A free-falling hammer was dropped at midspan with the same total kinetic energy input but varying mass and momentum. The specimens under the repeated impact test were struck two times at the same location. The colliding index, defined as the impact energy-momentum ratio, was proposed to explain the different impact responses under equal-energy impacts. The increase of colliding index from low to high indicates the transition of the impact response from static to dynamic and failure mode from flexure to shear. This phenomenon was more evident when the column had a greater axial load and was impacted with a high colliding index. The existence of the axial load had an inhibitory effect on the crack development and increased the shear resistance. The second impact changes the failure mode from flexural to brittle shear as found in the specimen with 20% axial load subjected to high a colliding index. Moreover, a deflection prediction equation based on the impact energy and force was limited to the low colliding index impact.

An image-based deep learning network technique for structural health monitoring

  • Lee, Dong-Han;Koh, Bong-Hwan
    • Smart Structures and Systems
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    • v.28 no.6
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    • pp.799-810
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    • 2021
  • When monitoring the structural integrity of a bridge using data collected through accelerometers, identifying the profile of the load exerted on the bridge from the vehicles passing over it becomes a crucial task. In this study, the speed and location of vehicles on the deck of a bridge is reconfigured using real-time video to implicitly associate the load applied to the bridge with the response from the bridge sensors to develop an image-based deep learning network model. Instead of directly measuring the load that a moving vehicle exerts on the bridge, the intention in the proposed method is to replace the correlation between the movement of vehicles from CCTV images and the corresponding response by the bridge with a neural network model. Given the framework of an input-output-based system identification, CCTV images secured from the bridge and the acceleration measurements from a cantilevered beam are combined during the process of training the neural network model. Since in reality, structural damage cannot be induced in a bridge, the focus of the study is on identifying local changes in parameters by adding mass to a cantilevered beam in the laboratory. The study successfully identified the change in the material parameters in the beam by using the deep-learning neural network model. Also, the method correctly predicted the acceleration response of the beam. The proposed approach can be extended to the structural health monitoring of actual bridges, and its sensitivity to damage can also be improved through optimization of the network training.

Analysis of the change in appearance according to the hardening method of leather (가죽의 경화방법에 따른 외형변화 분석)

  • Youshin, Park
    • Journal of Fashion Business
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    • v.26 no.5
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    • pp.122-134
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    • 2022
  • This study is conducted on hardening leather with improved firmness and stability of shape, based on research on types and thickness of leather. The purpose of this study is to test the physical properties of the leather for molding to prepare the foundation for leather molding based on the test results using four methods by thickness of Vegetable and Split. The tests were conducted using a total of five leather types, including three types of vegetable leathers and two types of split, by thickness. Based on the testing method for leathers in KS M 6882, the tests were performed at 27℃ with relative humidity of 65±20%. The samples were prepared with cowhide, size 9cm× 2cm. The measurement parameters are length and width. thickness, volume, mass, density. Regarding the hardening treatment method, changes in appearance and major physical characteristics of leather were reviewed by soaking in hot water, dry heating, hammering, waxing, and olive oil coating. The study results are as follows. In planar works, it is judged that hardening work using a hammer is more suitable for stiffness or density in order to prevent easy breakage with adult muscle density, rather than boiling water or baking. In conclusion, there is no curling, soot, or breaking phenomenon, and the densest curing method is 50℃ for 20 sec of V2 and 75℃ for 60 sec of V2 in boiling water. The combination of paraffin treatment improve waterproof and quality.

Effects of leucine-enriched essential amino acid supplementation on muscular fatigue and inflammatory cytokines in wheelchair basketball players

  • An, Young Hwan;Kim, Jisu;Kim, Hee-Jae;Lim, Kiwon
    • Korean Journal of Exercise Nutrition
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    • v.24 no.2
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    • pp.38-46
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    • 2020
  • [Purpose] This study aimed to investigate the effects of leucine-enriched essential amino acid (LEAA) supplementation on muscle fatigue and the level of inflammatory cytokines in wheelchair basketball players after a basketball game and interval training. [Methods] Of the ten recruited wheelchair basketball players (aged 34.5±8.9 years; lean body mass of 34.3±10.0 kg) who had spinal cord injury (SCI) and had undergone amputation, nine participated in the final test. These nine athletes received LEAA supplements (3 times 4.0 g/day) or placebo treatment in a double-blind, randomized, crossover study. We measured variables related to muscular fatigue and inflammatory response before the intense exercise and 4 days after recovery. [Results] The significant effect of LEAA supplementation was inhibition of circulating IL-6 levels in the LEAA-treated group compared with the placebo group (P < .05). However, no changes were observed in the TNF-α and creatinine kinase levels. Moreover, analysis of variance analysis showed no significant difference in the relative values of muscle soreness. However, the effect size analysis with Cohen's d reported a significant improvement in the relative values of whole body and back muscle soreness. [Conclusion] Our results revealed that LEAA supplementation before and after intense exercise could help reduce muscle soreness and IL-6 levels in wheelchair basketball players.

Evaluation of Ammonia Removal Mechanisms and Efficiencies Through Batch Experiments (배치 실험을 이용한 암모니아 제거 기작 및 효율 평가)

  • Jang, Jieun;Kang, Jiyoung;Kim, Hye Won;Shin, Kyu Jin;Jeen, Sung-Wook
    • Journal of Soil and Groundwater Environment
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    • v.27 no.6
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    • pp.37-46
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    • 2022
  • As the amount of livestock wastewater increases, ammonia contamination in surface water and groundwater is also increasing, and its treatment is urgently needed. In this study, indigenous soil bacteria was utilized for ammonia removal in artificial wastewater and associated removal mechanisms and efficiencies were evaluated. Two batch reactors were configurated to contain natural soil and artificial wastewater at 1:10 mass ratio, and incubated for 84 and 168 hours, respectively. The results showed that ammonia was completely removed within 48 and 72 hours in the first and second reactors, respectively. There were no significant changes in ammonia concentrations in the control groups without soil. Nitrate was formed in the reactors, indicating that the main removal mechanism of ammonia was nitrification by nitrifying bacteria. Nitrate was further converted to nitrogen gas by denitrification in the anaerobic environment, which was caused by consumption of oxygen during the nitrification process.

The effect of fibroblast growth factor receptor inhibition on resistance exercise training-induced adaptation of bone and muscle quality in mice

  • Cho, Suhan;Lee, Hojun;Lee, Ho-Young;Kim, Sung Joon;Song, Wook
    • The Korean Journal of Physiology and Pharmacology
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    • v.26 no.3
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    • pp.207-218
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    • 2022
  • Aging in mammals, including humans, is accompanied by loss of bone and muscular function and mass, characterized by osteoporosis and sarcopenia. Although resistance exercise training (RET) is considered an effective intervention, its effect is blunted in some elderly individuals. Fibroblast growth factor (FGF) and its receptor, FGFR, can modulate bone and muscle quality during aging and physical performance. To elucidate this possibility, the FGFR inhibitor NVP-BGJ398 was administrated to C57BL/6n mice for 8 weeks with or without RET. Treatment with NVPBGJ398 decreased grip strength, muscular endurance, running capacity and bone quality in the mice. FGFR inhibition elevated bone resorption and relevant gene expression, indicating altered bone formation and resorption. RET attenuated tibial bone resorption, accompanied by changes in the expression of relevant genes. However, RET did not overcome the detrimental effect of NVP-BGJ398 on muscular function. Taken together, these findings provide evidence that FGFR signaling may have a potential role in the maintenance of physical performance and quality of bone and muscles.

Glutaric Aciduria Type I: The Newborn Screening Program Changes the Outcomes of the Disease (글루타르산뇨증 1형: 신생아 대사이상 검사 시행 이후 변화를 중심으로)

  • Kim, Su Jin
    • Journal of The Korean Society of Inherited Metabolic disease
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    • v.22 no.1
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    • pp.9-14
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    • 2022
  • Glutaric aciduria type 1 (GA1; OMIM #231670) is a rare autosomal recessive inherited neurometabolic disorder caused by the deficiency of glutaryl-CoA dehydrogenase. Infantile-onset GA1 is the most common form characterized by striatal injury and progressive movement disorder, and it is often triggered by an acute encephalopathic crisis within the first three years of life. Once this crisis occurs, there is a high likelihood for ineffective or limited conventional interventions, neurological disorders, or even death. Therefore, early diagnosis and immediate preventive management, such as dietary therapy, is essential. In the past decades, newborn screening (NBS) by tandem mass spectrometry for GA1 has been largely introduced in many countries including Korea, and it has led to improvements in the neurological outcomes of patients with GA1. In this review, the clinical symptoms, natural histories, and outcomes before and after the introduction of NBS in patients are discussed.