• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.311-316
• /
• 2002

The following results are achieved from a mortar flow test depending on stainless steel slag fineness, rate of replacement, and a research on material age compressive strength, strength activity index. 1. Flow is proportional to the stainless steel slag fineness. 2. Mixing stainless steel slag decreases compressive strength 3. Material age compressive strength has the maximum value when stainless steel slag fineness is 6000$cm^2$/g. 4. Material age 7day strength activity index satisfies KSCE 95-01 at all conditions except the case of fineness 8000$cm^2$/gㆍstainless steel slag rate of replacement 30%. 5. Material age 28day strength activity index satisfies KSCE 95-01 in case of stainless steel slag fineness 4000$cm^2$/gㆍrate of replacement 10%, fineness 6000$cm^2$/gㆍ10%, or 20%.

• Resources Recycling
• /
• v.26 no.1
• /
• pp.11-15
• /
• 2017

The amount of the wood chip ash is expected to increase continuously as demand of wood chip-based heat and electricity increase. Thus, there is increased interest in wood chip ash utilization. In this study, as a program of utilization in wood chip ash, the physical and chemical properties of wood chip ashes generated from a combined heat and power plant were investigated. The chemical analysis showed that the main contents of wood chip ash are composed of silica, alumina and alkali. A possibility of reuse as secondary cementitious materials was investigated by the analysis of strength activity index, and compared with coal ash. The highest value for Strength activity index of wood chip fly ash was 78% at 90 days curing time. This result revealed that wood chip fly ash has the potential to be utilized as the admixture for cementitious material.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2002.05a
• /
• pp.69-74
• /
• 2002

The following results are achieved from a mortar flow test depending on stainless steel slag fineness, replacement ratio, and a research on material age compressive strength, strength activity index. 1. Flow is proportional to the stainless steel slag fineness within the limits of 4000~8000$\textrm{cm}^2$/g, but in the case of fineness 20000$\textrm{cm}^2$/g flow decreases at all conditions except the case of replacement ratio 10%. 2. As stainless steel slag replacement ratio increases, Mortar of flow somewhat decreases. 3. As stainless steel slag blends, compressive strength decreases, but in proportion to the increase of age, compressive strength increases. 4. As stainless steel slag replacement ratio, compressive strength decreases. 5. In the case of stainless steel slag fineness 6000$\textrm{cm}^2$/g and 20.000$\textrm{cm}^2$/g, compressive strength of revelation ratio has the maximum value when it's replacement ratio is 10%.

• Journal of The Korean Society of Integrative Medicine
• /
• v.11 no.2
• /
• pp.181-196
• /
• 2023

Purpose : The purpose of this study was to investigate the effects of physical activity on impaired fasting glucose in adults aged 20 years or older. Methods : This study utilized raw data from the 8th National Health and Nutrition Examination survey (2019~2021). The subjects of this study were 5,344 adults aged 20 years or older who were confirmed to be free of diabetes. The control variables in this study model are health behavior characteristics (subjective health status, smoking, drinking), anthropometric characteristics (body mass index), and personal background characteristics (gender, age, income level, education level, marital status). As for the analysis method, the degree of physical activity was made into a dummy variable, and a probit model was used. Results : As a result of this study, compared to quartile 1 of the relative grip strength value obtained by dividing the grip strength by the body mass index (body mass index, kg, m²), fasting blood glucose levels were significantly higher in quartile 2 (.05, p<.01), quartile 3 (.04, p<.01), and quartile 4 (.04, p<.01). It was found that the probability of belonging to the normal category was higher than that of impaired fasting glucose. In addition, in the group of adults aged 20 or older who had a lot of aerobic and anaerobic physical activity, fasting blood sugar was more likely to be in the normal category. Conclusion : Based on the results of this study, it was suggested that diabetes should be managed through physical activity in the pre-diabetic stage, as prevention is important as well as treatment. From a practical point of view, muscle strength, such as grip strength, can be identified as a reliable indicator for identifying impaired fasting glucose.

• International Journal of Concrete Structures and Materials
• /
• v.8 no.2
• /
• pp.173-182
• /
• 2014

An experimental investigation was carried out to evaluate the mechanical properties of concrete mixtures in which coarse aggregate was partially (30, 50 or 70 %) replaced with pre-washed municipal solid waste incineration (MSWI) bottom ash. Results indicated that bottom ash reduced the compressive strength, elastic modulus, and levels of heavy metals in leachate when used as a replacement for gravel, and that the maximum amount of MSWI bottom ash in concrete should not exceed 50 %. To analyze the effect mechanism of bottom ash in concrete, the degree of hydration and the following pozzolanic reaction characterized by the pozzolanic activity index, and the porosity distribution in cement mortar. The study indicates that improved properties of concrete are not solely later strength gain and reduced levels of heavy metals in leachate but also the progression of pozzolanic reactions, where a dense structure contains a higher proportion of fine pores that are related to durability.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.883-888
• /
• 2001

In Korea, countermeasures against earthquake disasters such as the seismic performance evaluation and/or retrofit scheme of buildings have not been fully performed since Korea had not been experienced many destructive earthquakes in the past. The main objective of this paper is to propose the basic seismic protection index (Es) suitable to Korean buildings based on the seismic evaluation of existing reinforced concrete buildings using modified strength index. This paper will focus on 1) the selection of weak and moderate earthquake waves representing Korean seismic zone, 2) the creation of the required strength ratio spectra by seismic response analysis, and 3) the proposition of the basic seismic protection index (Es) suitable to Korean seismic activity based on required strength ratio spectra

• Korean Journal of Exercise Nutrition
• /
• v.25 no.2
• /
• pp.26-32
• /
• 2021

[Purpose] This study aimed to analyze the prevalence of hypertension according to the body mass index (BMI) and relative handgrip strength (RHGS) among elderly individuals in Korea. [Methods] We analyzed the data of 44,183 Korean elderly individuals over 65 years old (men: n = 15,798, age = 73.31 ± 5.04 years, women: n = 28,385, age = 72.14 ± 5.04 years) obtained from the Korean National Fitness Assessment in 2019. All the participants were categorized into three groups according to the BMI and RHGS; additionally, one-way ANOVA and logistic regression analysis were performed. [Results] Overweight (men: 1.16 odds ratio [OR] 1.06-1.26, 95% confidence interval [CI]; women: 1.15 OR, 1.07-1.23 95% CI) and obese (men: 1.54 OR, 1.42-1.66 95% CI; women: 1.44 OR, 1.36-1.53 95% CI) elderly individuals showed a higher prevalence of hypertension than elderly individuals with normal weight, after controlling for age. In men, a lower RHGS was associated with a higher prevalence of hypertension after controlling for age (weak RHGS: 1.09 OR, 1.00-1.17 95% CI; middle RHGS: 1.21 OR, 1.12-1.31 95% CI vs. strong RHGS). [Conclusion] A higher BMI was associated with the prevalence of hypertension in the elderly Korean population. In addition, a lower RHGS was associated with the prevalence of hypertension in elderly Korean men.

• Computers and Concrete
• /
• v.11 no.2
• /
• pp.93-104
• /
• 2013

The use of rock wool waste, an industrial by-product, in cement-based composites has positive effects on the environment because it reduces the problems associated rock wool disposal. The experiments in this study tested cement-based composites using various rock wool waste contents (10, 20, 30 and 40% by weight of cement) as a partial replacement for Portland cement in mortars. The pozzolanic strength activity test, flow test, compressive strength test, dry shrinkage test, absorption test, initial surface absorption test and scanning electron microscope observations were conducted to evaluate the properties of cement-based composites. Test results demonstrate that the pozzolanic strength activity index for rock wool waste specimens is 103% after 91 days. The inclusion of rock wool waste in cement-based composites decreases its dry shrinkage and initial surface absorption, and increases its compressive strength. These improved properties are the result of the dense structure achieved by the filling effect and pozzolanic reactions of the rock wool waste. The addition of 30% and 10% rock wool wastes to cement is the optimal amount based on the results of compressive strength and initial surface absorption for a w/cm of 0.35 and 0.55, respectively. Therefore, it is feasible to utilize rock wool waste as a partial replacement of cement in cement-based composites.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.4
• /
• pp.295-309
• /
• 2013

In order to investigate of technology competitiveness for domestic engineering enterprise, using the quantitative and objective patent. In these result, the technology competitiveness(Patent Activity Index, Patent Family Size Index, Patent Impact Index, Technology strength) of our enterprise is far inferior to another country. So we should try to achieve our superiority in competitive power, we devote ourself to put through technical improvements of our domestic engineering enterprise in many ways.

• Physical Therapy Rehabilitation Science
• /
• v.13 no.1
• /
• pp.134-142
• /
• 2024

Objective: This study aimed to compare the subjective health status, physical activity index, and perceived stress rate of obese children with those of healthy children through propensity matching analysis and to use the results to help manage obese children. Design: Descriptive correlation study. Methods: This study conducted a secondary analysis using raw data from the National Health and Nutrition Examination Survey. Propensity matching (1:2) was conducted between obese and healthy adolescents. Results: The number of days of physical activity was 1.22 days for the obese adolescent group and 1.01 days for the non-obese adolescent group, which was higher in the obese group (p=0.003). The subjective health status was 3.43 and 3.81 in the obese and non-obese adolescent groups, respectively, showing a higher difference in the normal group (p<0.001). No statistical difference was observed in the perceived stress rate (p=0.871) or strength exercises (p=0.190) between the two groups. Conclusion: This study suggests the need for development measures to effectively improve youth physical activity, muscle-strengthening programs, stress management, and subjective health status in obese and normal groups.