• Title/Summary/Keyword: Stress Deviation

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Classification of Shear Strength according to Breccia Content in Fault Core (단층각력 함량에 따른 전단강도의 분류)

  • Yun, Hyun-Seok;Moon, Seong-Woo;Seo, Yong-Seok
    • Economic and Environmental Geology
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    • v.53 no.2
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    • pp.167-181
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    • 2020
  • Analysis of variance (ANOVA) and multiple comparison analysis were performed for shear strengths categorized by breccia content of 5 wt.% (Case-I), 10 wt.%, (Case-II) and 15 wt.% (Case-III) in fault cores. The relationship between breccia contetnt and shear strength was quantitatively classified by calculating the mean and standard deviation of shear strength for each population in each case and then the grouping the breccia contents that had a statistically similar effect on the dispersion of shear strength. As a result, shear strength was clearly classified into group 1 (breccia content of 0-15 wt.%) and group 2 and 3 (breccia coantent of 15-30 wt.% and 30 wt.% or more) in Case-III. Shear strength of the standard line at breccia content of 15 wt.% were determined to be 43.6 kPa, 77.6 kPa, and 118.6 kPa at each normal stress (54 kPa, 108 kPa, and 162 kPa), respectively. In addition, the distribution range of cohesions is 0-43.6 kPa at breccia content of 15 wt.% or less, and 0-70.0 kPa at 15 wt.% or more. Distribution range of friction angles is 0-45.7 ° at breccia content of 15 wt.% or less, and 16.7-57.5 ° at 15 wt.% or more.

Comparative Research on Ego, Marriage and Parenting-Related Psychological Characteristics of Mothers of Normal Infants and Mothers of Infants with Developmental Risk: Focus on the 3rd Year Data from the Panel Study on Korean Children (위험 발달군 영아의 어머니와 일반 영아 어머니의 자아, 결혼, 양육관련 심리적 특성 비교연구: 한국 아동 패널 3차년도 자료를 중심으로)

  • Yu, Seung Yeon;Lim, Ji Sun;Kim, Yeon Ha
    • Korean Journal of Childcare and Education
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    • v.10 no.5
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    • pp.211-228
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    • 2014
  • The present study aims to identify the ego, marriage and parenting-related psychological characteristics of mothers of infants with developmental risk, as well as to perform comparative analysis between their psychological characteristics and those of mothers of normal infants. For this purpose, we used SPSS 21 statistical software to calculate the average and standard deviation values, and also conducted frequency analysis and t-tests. The study subjects were mothers of 1584 normal infants and 186 infants with developmental risk, who were classified by Korean Denver II developmental screening test from a total of 1802 families listed in the 3rd year data from the Panel Study on Korean Children in 2010. Our results revealed a significant difference in the martial satisfaction and husbands' parenting participation between two groups, among the marriage-related psychological characteristics. There was also a significant difference in the parenting knowledge, style and stress among the parenting-related psychological characteristics. However, a statistically significant difference was not observed in the ego-related psychological characteristics of mothers. These results are thought to serve as baseline data for the infants with developmental risk at the precautionary level.

A Study on Health Perception and Health Promoting Behavior in the Elderly (노인의 건강지각과 건강증진행위)

  • Lee, Kyeong-Sook;Chung, Young-Sook
    • Research in Community and Public Health Nursing
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    • v.9 no.1
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    • pp.72-88
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    • 1998
  • This study was designed to identify the relationship between health perception arid health promoting behavior in the elderly. The subjects for this study were 92 persons over 65, who could be easily met in households, pavilions for the aged, and parks. The data were collected during the period from March 24th to April 12th, 1997 by interviews with a structured questionnaire. The instruments used for this study are as follows: The Health Perception Questionnaire developed by Ware (1979) and translated by Yu Ji-Su(1985). The Health Promotion Lifestyle Profile(HPLP) developed by Walker, Sechrist & Pender (1987) and partially amended by the author of this study. The Health Promotion Lifestyle Profile(HPLP) was parameterized by nutrition, exercise, stress management, self actualization, health responsibility, and interpersonal support. The data was analyzed by frequency, percentage, mean, standard deviation, t - test, ANOVA, and Pearson's correlation using an SPSS program. The results of this study were as follows: 1. Hypothesis 1 : 'The higher the level of health perception in the elderly, the higher the practice of health promoting behavior in the elderly' was supported(r=0.449, p<0.001). 2. The health perception mean score on a four point scale was 2.564. 3. For health promoting behavior, the mean score on a four point scale was 2.560. The factor of the highest mean score was interpersonal support(2.850) and factor of the lowest mean score was exercise(1.964). 4. Among the general characteristic variables, sex(t=4.12, p<0.001), religion(t=2.47, p<0.05), education(F=3.27, p<0.05), marital status (t=2.22, p<0.05), living situation(F=3.50, p<0.05), and hobby(t= -2.57, p<0.05) showed strong connections to health perception. 5. Among the general characteristic variables, religion(t = 1.83, p<0.05), and marital status(t= 2.12, p<0.05) showed strong connections to health promoting behavior. In conclusion, this study revealed that health perception is an important factor related to health promoting behavior in the elderly. The general characteristic variables showed strong connections to health perception and health promoting behavior. Therefore, nurses should consider health perception and general characteristic variables when they plan nursing intervention for the elderly. Also, educational programs encouraging constructive health perception should be developed.

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Source Characteristics of the Recent Earthquakes for Seven Years in the Southwestern Region of the Korean Peninsula (최근 7년간 한반도 남서부 지역에서 발생한 지진의 진원 특성)

  • Jung, Mi Kyeong;Kyung, Jai Bok
    • Journal of the Korean earth science society
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    • v.34 no.1
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    • pp.59-68
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    • 2013
  • Focal mechanism solutions in the southwestern region of the Korean Peninsula ($34^{\circ}N-36^{\circ}N$, $126^{\circ}E-128^{\circ}E$) were obtained from the analysis of the recent 22 earthquakes ($M{\geq}2.0$) occurred from January, 2005 to March, 2011. The spatial differences between the epicenters recalculated by this study and those by KMA (Korea Meteorological Administration) and KIGAM (Korea Institute of Geoscience and Mineral Resources) are less than $0.05^{\circ}$, indicating a small deviation. However, they become a little bit larger in the coastal area due to a biased arrangement of seismic stations. Redetermined depths of hypocenters show a difference less than 12.7 km by comparison with the depth data announced by KIGAM. Most epicenters in inland area are located closely to the lineaments. Fault plane solutions were obtained from the analysis of P and SH wave polarities, and SH/P amplitude ratios. They show strike-slip faulting or strike-slip faulting with reverse components dominantly. The P-axes trends are mainly ENE-WSW or E-W directions. The direction of fault plane and auxiliary plane with 'NNE-SSW and WNW-ESE' or 'NE-SW and NW-SE' are dominant and almost parallel to the general trends of lineaments in the study area.

Microparticulation/Air Classification of Rice Bran: Characteristics and Application (초미세분쇄/공기분급을 이용한 탈지미강 분획의 특성과 응용)

  • Park, Dong-June;Ku, Kyung-Hyung;Mok, Chul-Kyoon
    • Korean Journal of Food Science and Technology
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    • v.25 no.6
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    • pp.769-774
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    • 1993
  • Defatted rice bran was microparticulated using fluidized bed opposed jet mill and air-classified at different air classifying wheel speed (ACWS) in Turboplex classifier. The median particle size and the standard deviation decreased, and concomitantly the specific surface area increased generally with increasing ACWS. The protein, fat and ash contents of the recovered rice bran increased with ACWS. The contents of minerals; magnesium, zinc, iron and manganese; increased positively with ACWS. The phytic acid content, however, was slightly higher at middle ACWS. The dietary fiber content was highest in the ACWS 15,000 rpm fraction showing 31.47%. Higher ACWS resulted in lighter colored powder. The water holding capacity (WHC) showed the maximum value at ACWS 12,000 rpm and decreased with increasing ACWS, while the oil holding capacity (OHC) increased with ACWS. The rheological property of the microparticulated rice bran/water suspension fitted to the linear model. The yield stress and viscosity of the suspension increased with ACWS. The shape of microparticulated rice bran at ACWS 21,000 rpm was spherical, and the median particle size was $3.7{\mu}m$. When cake was prepared with substitution of microparticulated rice bran at 5%, the cake height and volume increased remarkably.

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Self-Sensing of Single Carbon Fiber/Carbon Nanotube-Epoxy Composites Using Electro-Micromechanical Techniques and Acoustic Emission (전기적-미세역학시험법과 음향방출을 이용한 단일 탄소섬유/탄소나노튜브-에폭시 나노복합재료의 자체-감지능)

  • Park, Joung-Man;Jang, Jung-Hoon;Wang, Zuo-Jia;Kwon, Dong-Jun;Park, Jong-Kyu;Lee, Woo-Il
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.5
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    • pp.411-422
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    • 2010
  • Self-sensing on micro-failure, dispersion degree and relating properties, of carbon nanotube(CNT)/epoxy composites, were investigated using wettability, electro-micromechanical technique with acoustic emission(AE). Specimens were prepared from neat epoxy as well as composites with untreated and acid-treated CNT. Degree of dispersion was evaluated comparatively by measuring volumetric electrical resistivity and its standard deviation. Apparent modulus containing the stress transfer was higher for acid-treated CNT composite than for the untreated case. Applied cyclic loading responded well for a single carbon fiber/CNT-epoxy composite by the change in contact resistivity. The interfacial shear strength between a single carbon fiber and CNT-epoxy, determined in a fiber pullout test, was lower than that between a single carbon fiber and neat epoxy. Regarding on micro-damage sensing using electrical resistivity measurement with AE, the stepwise increment in electrical resistivity was observed for a single carbon fiber/CNT -epoxy composite. On the other hand, electrical resistivity increased infinitely right after the first carbon fiber breaks for a single carbon fiber/neat epoxy composite. The occurrence of AE events of added CNT composites was much higher than the neat epoxy case, due to micro failure at the interfaces by added CNTs.

Structural Capacity of High Strength Steel Pipe Pile After Pile Driving (고강도 강관말뚝의 항타후 구조성능 분석)

  • La, SeungMin;Yoo, Hankyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.6C
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    • pp.251-258
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    • 2011
  • Steel pipe piles have been used as various deep foundation materials for a long time. Recent increase in steel material cost has made engineers reluctant in using it even with its good quality and ease of construction. Therefore when constructing with steel pipe pile, the decision to reuse the excessive pile length that is cut off from the designed pile head elevation after pile driving can be cost saving. This has caused many constructors to reuse the pile leftovers with new piles, but the absence of quantitative structural capacity behaviors of steel pipe pile after pile driving or appropriate countermeasures and standards in reusing steel pipe pile has resulted in wrong applications, pile structural integrity problems, inappropriate limitation of reusable pile length, etc. The structural performance analysis between a new pile and a pile that has undergone working state and ultimate state stress level during pile driving was performed in this research by means of comparing the results between the dynamic pile load test, tensile load test, charpy energy test and fatigue test for high strength steel of $440N/mm^2$ yield strength. Test results show that under working load conditions the yield strength variation is less than 2% and for ultimate load conditions the variation is less than 5% for maximum total blow count of 3000. The results have been statistically analyzed to check the sensitivity of each factors involved. From the test results, reusability of steel pipe pile lies not in the main pipe yield strength deviation but in the reduction of absorb energy, strength changes and quality control at the welded section, shape deformation and local buckling during pile driving.

Evaluation of Coronary Artery Disease with Gated Blood Pool Scan Using Dipyridamole (Dipyridamole 부하 심장 풀 스캔을 이용한 관동맥질환의 평가)

  • Kim, Gwang-Weon;Choi, Chung-Il;Chung, Byung-Cheon;Lee, Jae-Tae;Lee, Kyu-Bo;Chae, Shung-Chull;Jun, Jae-Eun;Park, Wee-Hyun;Park, Hee-Myung
    • The Korean Journal of Nuclear Medicine
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    • v.25 no.1
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    • pp.27-36
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    • 1991
  • Thirty-one patients with coronary artery disease and twenty-sir normal subjects underwent $^{99m}Tc-GBPS$ before and after coronary vasodilatation was induced by dipyridamle 0.54 mg/kg given IV over 4 min. LVEF, ${\Delta}EF$ and regional wall motion by phase analysis were measured during rest and dipyridamole infusion. The results were as follows: 1) Mean LVEF of normal subjects was significantly higher than that of MI group (p=0.001), but similar to that of angina group during rest. Among MI group, mean LVEF of anterior MI group was significantly lower than that of inferior MI group during rest (p=0.024). 2) The normal subjects had a significaat increase in mean LVEF during dipyridamole infusion $(+12{\pm}3.8)$, while the CAD group had no increase $(+2{\pm}5.0)$ (p<0.001). If an increase of LVEF during stress is less than 5%, it suggests an abnormality. The sensitivity and specificity of LVEF changes after dipyridamole infusion were 81%, 96%, respectively. 3) With phase analysis, LV mean phase angle of normal subjects and CAD patients was $143{\pm}20.5^{\circ},\;132{\pm}20.6^{\circ}$ respectively, durign rest (p=0.049). But an ncrease of LV mean phase angle during dipyridamole infusion in these two groups was not significantly different. Dipyridamole infusion did not affect standard deviation and FWHM of phase angle. 4) Regional wall motion was abnormal in 5 patients (16%) during dipyridamole infusion. 5) Side effects with dipyridamole infusion include; headache, angina pain, chest discomfirt, nausea, weakness sense. In conclusion, dipyridamole GBPS might be useful in detection and follow up of CAD.

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Reproducibility of an Automatic Quantitation of Regional Myocardial Wall Motion and Systolic Thickening on Gated Tc-99m-MIBI Myocardial SPECT (게이트 Tc-99m-MIBI SPECT에서 국소 심근운동과 수축기 심근두꺼워짐 자동정량화법의 재현성)

  • Paeng, Jin-Chul;Lee, Dong-Soo;Cheon, Gi-Jeong;Kim, Yu-Kyeong;Chung, June-Key;Lee, Myung-Chul
    • The Korean Journal of Nuclear Medicine
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    • v.34 no.6
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    • pp.487-496
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    • 2000
  • Purpose: The aim of this study is to investigate the reproducibility of the quantitative assessment of segmental wall motion and systolic thickening provided by an automatic quantitation algorithm. Materials and Methods: Tc-99m-MIBI gated myocardial SPECT with dipyridamole stress was performed in 31 patients with known or suspected coronary artery disease (4 with single, 6 with two, 11 with triple vessel disease; ejection fraction $51{\pm}14%$) twice consecutively in the same position. Myocardium was divided into 20 segments. Segmental wall motion and systolic thickening were calculated and expressed in mm and % increase respectively, using $AutoQUANT^{TM}$ software. The reproducibility of this quantitative measurement of wall motion and thickening was tested. Results: Correlations between repeated measurements on consecutive gated SPECT were excellent for wall motion (r=0.95) and systolic thickening (r=0.88). On Bland-Altman analysis, two standard deviation was 2 mm for repeated measurement of segmental wall motion, and 20% for that of systolic thickening. The weighted kappa values of repeated measurements were 0.807 for wall motion and 0.708 for systolic thickening. Sex, perfusion, or segmental location had no influence on reproducibility. Conclusion: Segmental wall motion and systolic thickening quantified using $AutoeUANT^{TM}$ software on gated myocardial SPECT offers good reproducibility and is significantly different when the change is more than 2 mm for wall motion and more than 20% for systolic thickening.

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A Study on the Property Changes of Rigid Polyurethane Foams by Nucleating Effects of PFA and MWCNT (PFA 및 MWCNT의 기핵효과에 의한 경질 폴리우레탄 폼의 물성 변화에 대한 연구)

  • Ahn, WonSool
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.4
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    • pp.2945-2950
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    • 2015
  • While perfluoroalkane (PFA), a liquid state nucleating agent for a rigid polyurethane foam (RPUF) to enhance the thermal insulation property, has the excellent nucleating characteristics, it is very expensive as well as environmentally harmful due to the fluoride compound. Many researches, therefore, have been performed to develop the alternative nucleating agents to replace PFA. In the present work, a multi-wall carbon nanotube (MWCNT) was used as a sloid state nucleating agent, and thereby the effects on the property changes of the RPUF were carried out. Average cell size decreased from 165.6 for base RPUF to $162.9{\mu}m$ and cell uniformity was also enhanced, showing the standard cell-size deviation of 45.6 and 35.2, respectively. While k-factor of base PUF was $0.01763kcal/m.hr.^{\circ}C$, that of the sample with 0.01 phr MWCNT showed 1.02% reduced value of $0.01745kcal/m.hr.^{\circ}C$. Though the compressive yield stress is nearly the same as $0.030{\times}105Pa$ for the both samples, initial modulus of the sample with 0.01 phr MWCNT was higher than that of base sample. it was considered as the results that small amount of MWCNT could play a sufficient role as the effective nucleating agent for RPUF, showing that an echo-friendly RPUF with reduced-cost could be fabricated, which has an enhanced thermal and mechanical properties.