• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.1-9
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• 2017

Spiral reinforcement in a circular column plays an effective role in the ductile behavior of a column through position fixing and buckling restraining of the longitudinal reinforcement, and confining core-concrete. Each country has suggested the minimum volumetric ratio of spiral reinforcement in order to secure the ductility of concrete columns. The minimum volumetric ratio of spiral reinforcement suggested by ACI 318-14 and the national concrete structure design standard was developed based on the theory of Richard et al. (1928); furthermore it has been used until now. However, their theory cannot consider the effects of high strength concrete and high strength reinforcement, and arrangement condition of the spiral reinforcement. In this study, a modified minimum volumetric ratio equation is suggested, which is required to improve the ductility of reinforced concrete circular columns and to recover their stress. The modified minimum volumetric ratio equation suggested here considers the effect of the compressive strength of concrete, the yield strength of spiral reinforcement, the cross sectional area of columns, the pitch of spiral reinforcements and the diameter of spiral reinforcement. In this paper, the validity of the minimum volumetric ratios from ACI 318-14 and this study was investigated and compared based on the results of uniaxial compression experiment for specimens in which the material strength and the spiral reinforcements ratio were used as variables. In the end of the study, the modification method for the suggested equation was examined.

• Fire Science and Engineering
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• v.33 no.4
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• pp.112-120
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• 2019

Benzene is a class 4 hazardous material according to the Act on the Safety Control of Hazardous Substances. This study qualitatively evaluated the damage size of a "toxic" accident and "pool fire" accidents based on benzene in a virtual scenario of a fire and leakage accident during unloading at a port facility. The KORA program was used as an evaluation method, which is supported as a universal program by the National Institute of Chemical Safety. The range of damage effects of a benzene-induced fire and leakage accident was predicted. In the case of toxic damage range, the accident's damage effect range for the "worst case scenario" was reduced by up to 5.11% with a decrease in the size of the leakage hole. In the case of the leakage time, the damage effect range increased to 145.12% with a 10 min leakage time compared to that of a 5 min leakage time and went up to 20 min (212.29%) with a 20 min leakage time. In the case of pool-fire-induced damage, the damage effect range by radiant heat in the "worst case scenario" was 228.8 m in radius from the center of the handling facility. In the "alternative scenario," the damage effect range by radiant heat was reduced by up to 8.26% compared to that in the "worst case scenario" since the size of the leakage hole was decreased by reducing the cross-sectional area of the pipe.

• Restorative Dentistry and Endodontics
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• v.31 no.6
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• pp.445-451
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• 2006

The purposes of this study were to compare the effects of one or two applications of all-in-one adhesives on microtensile bond strengths (${\mu}$TBS) to unground enamel and to investigate the morphological changes in enamel surfaces treated with these adhesives using a scanning electron microscopy (SEM). Twenty-five noncarious, unrestored human mandibular molars were used. The unground enamel surfaces were cleansed with pumice. The following adhesives were applied to lingual, mid-coronal surfaces according to manufacture's directions; Clearfil SE bond in SE group, Adper Prompt L-Pop$^{TM}$1 coat in LP1 group, 2 coats in LP2 group, Xeno$^{\R}$III1 coat in XN1 group, and 2 coats in XN2 group. After application of the adhesives, a hybrid light-activated resin composite was built up on the unground enamel. Each tooth was sectioned to make a cross-sectional area of approximately 1.0 mm$^2$ for each stick. The microtensile bond strength was determined. Each specimen was observed under SEM to examine the morphological changes. Data were analyzed with one-way ANOVA. The results of this study were as follows; 1. The microtensile bond strength values were; SE (19.77 ${\pm}$ 2.44 MPa), LP1 (13.88 ${\pm}$ 3.67 MPa), LP2 (14.50 ${\pm}$ 2.52 MPa), XN1 (14.42 ${\pm}$ 2.51 MPa) and XN2 (15.28 ${\pm}$ 2.79 MPa). SE was significantly higher than the other groups in bond strength (p < 0.05). All groups except SE were not significantly different in bond strength (p < 0.05). 2. All groups were characterized as shallow and irregular etching patterns.

• Journal of agricultural medicine and community health
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• v.23 no.2
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• pp.193-204
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• 1998

Cardiovascular diseases are the leading cause of death and disability in Korea. Their risk factors can be classified as either modifiable or nonmodifiable and among modifiable factors are high bood pressure, elevated blood cholesterol, obesity and cigarette smoking. The purpose of this study was to evaluate the risk factors for the cardiovascular diseases in a rural community and to get basic data for the development of a community-based rick reduction intervention program. Evaluation involved population-based, cross-sectional samples of adult residents in a rurual community. We measured blood pressure, body fat percent by bioelectric impedance fatness analyzer and serum cholesterol and interviewed adult residents over 20-year-old age. Blood pressure was checked twice and hypertension was classified by the sixth report of the Joint National Committee on Detection. Evaluation, and Treatment of High Blood Pressure. The Cutpoints for high blood cholesterol was used National Cholesterol Treatment Guidelines and those for obesity was 25% in male. 30% in female. The results were as follows: 1. Prevalence of definitive hypertension was 59.7% in males and 54.4% in female. 2. Prevalence of hypercholesterolemia was 14.3% in male and 18.2% in female. 3. Prevalence of obese was 10.7% in male and 41.1% in female. 4. Among definitive hypertension, hypercholesterolemia, and obesity 52.1% possessed one risk factor, 12.6% two risk factors and 2.5% three risk factors in males. In females 41.4% possessed one risk factor and 27.6%. 5.7% respectively. 5. The smoking rate was 65.8% in males and 5.2% in females. Our results are used effectively for the community-based intervention towards cardiovascukr diseases risk reduction. However, because of limitations in our study design, further datas are needed including other risk factors and in-person clinical datas.

• Physical Therapy Korea
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• v.23 no.3
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• pp.21-28
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• 2016

Background: The toe-spread-out (TSO) exercise has been introduced as a strengthening exercise for the abductor hallucis muscle in subjects with hallux valgus. Visual biofeedback using ultrasound imaging during exercise, may increase the ability to selectively contract the abductor hallucis muscle, compared with exercise alone. Objects: The aim of this study was to investigate the effects of ultrasound imaging visual feedback during the TSO exercise with respect to its influence on the angle of the first metatarsophalangeal joint (1st MPJ) and the cross-sectional area (CSA) of the abductor hallucis muscle in subjects with hallux valgus. Methods: Twenty-five healthy young subjects with a mean average age of 22.5 years, and a standard deviation of 2.3 years, were recruited for this study. Hallux valgus was defined as an angles greater than $15^{\circ}$ angle of 1st MPJ. Goniometric measurement was used to determine the angle of 1st MPJ. In addition, an ultrasound system was used to collect the CSA of the abductor hallucis muscle in each foot. The angle of the 1st MPJ and CSA of the abductor hallucis were measured in three positions; the resting position, during TSO exercise, and during TSO exercise in conjunction with real-time ultrasound imaging feedback. All data analyzed using a repeated analysis of variance with Bonferroni correction in order to compare the dependent variables in all three positions. Statistical level of significance was set up as p<.05. Results: The angle of the 1st MPJ was noted to be significantly reduced and the CSA of the abductor hallucis to be significantly greater during TSO exercise used in conjunction with ultrasound imaging visual feedback, compared to when the values were recorded during TSO exercise alone (p<.05). Conclusion: Based on these findings, it can be concluded that the application of ultrasound imaging visual feedback during TSO exercise is more effective in contracting selectively the abductor hallucis than the use of exercise alone.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1025-1032
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• 2005

This paper presents experimental and analytical studies on long-term behavior of square CFT columns with diaphragm. In order to investigate the effect of the diaphragm on the long~term behavior, experiments for six specimens with two diaphragms and three different column length, and three-dimensional finite element analysis for each specimen have been performed. The finite element models considering the interface behavior between the steel tube and the inner concrete were verified from comparison of the test results with the analysis results. From the test and the analysis results, the following conclusions were obtained. The confinement effect created by the diaphragm does not depends on column length and influences only a part of the whole column that is from the end to the depth which is the same to the width of the column. The shortening of the column with diaphragm which covers more than a half of the cross sectional area of the inner concrete is the same as that of the column under a load applied on the steel tube and the entire section of the inner concrete.

• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.321-330
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• 2011

Recently, the effects of high temperature and fiber content on the residual mechnical properties of high-strength concrete were experimentally investigated. In this paper, residual mechanical properties of concrete with water to cement (w/c) ratios of 0.55, 0.42 and 0.35 exposed to high temperature are compared with those obtained in fiber reinforced concrete with similar characteristics ranging from 0.05% to 0.20% polypropylene (PP) fiber volume percentage. Also, factors including pre-load levels of 20% and 40% of the maximum load at room temperature are considered. Outbreak time, thermal strain, length change, and mass loss were tested to determine compressive strength, modulus of elasticity, and energy absorption capacity. From the results, in order to prevent the explosive spalling of 50 MPa grade concretes exposed to high temperature, more than 0.05 vol. % of PP fibers is needed. Also, the cross-sectional area of PP fiber can influence the residual mechanical properties and spalling tendency of fiber reinforced concrete exposed to high temperature. Especially, the external loading increases not only the residual mechanical properties of concrete but also the risk of spalling and brittle failure tendency.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.1
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• pp.33-39
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• 1996

The aim of this study is to estimate the prevalence of obesity and factors with it Ulsan secondary school girls. A cross-sectional study involving a sample of 485 students aged 12 to 15 years was obtained form secondary schools. Obesity was determined using body mass index(BMI=wt/Ht$^2$). The findings revealed that the average BMI was 19.3, and 4.5% of girls were either overweight and obese(BMI$\geq$25). Subjects were grouped into three categories based on the BMI, sibling obesity, self-consciousness of obesity, eating patterns such as eating snack after dinner and prejudice in food selection, and food frequency score were significantly associated nth BMI, while nutrition knowledge score was not associated with BMI. The fact that several social, environmental and health factors are associated with obesity means that a multisectorial intervention program must be considered in order to decrease the problem of overweight among secondary girls. Such program should include dietary intervention to modify food habits, nutrition education through mass media, introducing information on prevention and control obesity in school curriculum, and allocating sufficient time in the school schedule for exercise activities.

• The Journal of Fisheries Business Administration
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• v.30 no.1
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• pp.119-147
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• 1999

This article is subject to the rationalization of the cold-storage warehouse management, which gives the stabilization of the fishery production and the food life with respect to fisheries industry. In this point of view, the article examines to the structure of the cold-storage warehouse industry from the perspective of the industrial organization. To put it concretely, the article intends to apprehend the state of the structure of the industry and analyze the cold-storage warehouse's management activities. In addition, I try to find know the factors that affect the management performance(profitablity) of the industry through the cross-sectional correlation analysis. Finally, the conclusion of the article can be described as follows : \circled1 On the basis of the cold-storage capacity, there is the tendency that the industry concentrate in the area of Pusan(41.7%). \circled2 By formulating step of development of the industry, it is divided by six types. Type I is designed as raw material-storage warehouse for self-processing. Type IIis the raw material-storage warehouse for self-processing and storage-sale warehouse. Type III is the raw material-storage warehouse for self.distribution. Type IV is the raw material-storage warehouse for self-distribution and storage-sale warehouse. Type V is the net storage-sale warehouse. Type Ⅵ is the physical distribution center warehouse. Although each region has one representative type,6 types exist in all regions. \circled3 The competition structure of the industry has double structure on the basis of cold-storage capacity. \circled4 With respect to the management activity of the cold-storage warehouse, there is no change or even a decrease not increasing or not any change in sales from 1996 to 1997 \circled5 In order to try to induce the amount of shipper's materials, services that a cold-storage warehouse supply with its users include a custody-fee discount, a distribution-process service, a finance service, quality management service and so on. One of the best attractive services is the custody-fee service. \circled6 In the structure and management activity of the industry, the factors that affect management performance (profitablity) are a custody-fee discount, sales ability and capital structure of individual firm. Positive factor is sales ability and capital structure of individual firm. But, The custody-fee discount turns out to be a negative capital structure of individual film.

• Korean Journal of Community Nutrition
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• v.15 no.4
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• pp.513-524
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• 2010

This study was designed to examine nutrition label use, self-efficacy, snacking and eating behaviors of middle school students, and to investigate if these characteristics were different by nutrition label use. A cross-sectional survey was conducted to 348 middle school students in Kyunggi, Korea. About a third of subjects read nutrition labels when they purchased snacks/packaged foods. Most nutrition label users were interested in reading information on calories, fat and trans-fat. Self-efficacy of eating/selecting snacks or general nutrition behavior was moderate (mean score: 44.4 out of 60), with significantly higher score in nutrition label users compared to nonusers (p < 0.001). Nutrition label users felt more confident in 9 items out of 15 items of self-efficacy, such as "taking fruits instead of cookies/candy for snack" (p < 0.001), "choosing milk instead of soft drink" (p < 0.01), "not having snacks after dinner" and "avoiding processed foods for snacks" (p < 0.05). Subjects had snacks 1.3 times a day, and nutrition label nonusers consumed snacks more frequently than the counterparts (p < 0.01). About 55% of nutrition label users and 64.7% of nonusers mainly purchased snacks for themselves (p < 0.05). Commonly purchased snacks by adolescents were ice cream, cookies/chips, breads and ramen. Major considerations in purchasing snacks were taste (46.9%) and price (34.6%). In selecting snacks, the influence of friends and parents was greater than the other sources. Based on eating frequency of snacks, nutrition label users were more likely to consume healthy snacks, such as fruit juices, vegetables, milk, yogurt, and potato/sweet potato than nonusers (p < 0.05). Eating behaviors measured by 15 items scored 33.6 out of 45. Nutrition label users showed better eating behaviors, such as "eating meals slowly", "eating foods cooked with plant oil", and "eating out less frequently" (p < 0.05). Study results showed that majority of adolescents did not read nutrition labels, selected snacks for themselves and had somewhat unhealthy foods for snacks. This study also showed the differences in self-efficacy, snacking and eating behaviors between nutrition label users and nonusers. In nutrition education, it is necessary to stress the importance and skills for reading nutrition labels. It is also needed to help adolescents to select healthy snacks and have desirable eating behaviors, as well as increasing self-efficacy.