• Title/Summary/Keyword: Duncan

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Study on Mohr-Coulomb and Duncan-Chang Models in Tunnel Analysis (터널해석에 있어서 Mohr-Coulomb 및 Duncan-Chang 모델의 비교 연구)

  • Kim Dae-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.3
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    • pp.414-419
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    • 2006
  • In this paper, the numerical results using the Mohr-Coulomb and the Duncan-Chang models, on the stresses and strains of a tunnel under a deep open-cut site and the surrounding ground, were compared with each other. The Mohr-Coulomb model produced larger values than the Duncan-Chang model in stress and displacement of tunnel and ground.

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Study on the Estimation of Duncan & Chang Model Parameters-initial Tangent Modulus and Ultimate Deviator Stress for Compacted Weathered Soil (다짐 풍화토의 Duncan & Chang 모델 매개변수-초기접선계수와 극한축차응력 산정에 관한 연구)

  • Yoo, Kunsun
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.12
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    • pp.47-58
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    • 2018
  • Duncan & Chang(1970) proposed the Duncan-Chang model that a linear relation of transformed stress-strain plots was reconstituted from a nonlinear relation of stress-strain curve of triaxial compression test using hyperbolic theory so as to estimate an initial tangent modulus and ultimate deviator stress for the soil specimen. Although the transformed stress-strain plots show a linear relationship theoretically, they actually show a nonlinearity at both low and high values of strain of the test. This phenomenon indicates that the stress-strain curve is not a complete form of a hyperbola. So, if linear regression analyses for the transformed stress-strain plot are performed over a full range of strain of a test, error in the estimation of their linear equations is unavoidable depending on ranges of strain with non-linearity. In order to reduce such an error, a modified regression analysis method is proposed in this study, in which linear regression analyses for transformed stress-strain plots are performed over the entire range of strain except the range the non-linearity is shown around starting and ending of the test, and then the initial tangent modulus and ultimate deviator stresses are calculated. Isotropically consolidated-drained triaxial compression tests were performed on compacted weathered soil with a modified Proctor density to obtain their model parameters. The modified regression analyses for transformed stress-strain plots were performed and analyzed results are compared with results estimated by 2 points method (Duncan et al., 1980). As a result of analyses, initial tangent moduli are about 4.0% higher and ultimate deviator stresses are about 2.9% lower than those values estimated by Duncan's 2 points method.

Comparative effects of Apitoxin(Bee Venom) & Regular Acupuncture therapy on the knee joint arthritis induced by carrageenin solution in rats (침자(鍼刺) 및 봉독요법(蜂毒療法)이 Carrageenin으로 유발(誘發)된 흰쥐의 슬관절(膝關節) 염증성(炎症性) 부종(浮腫)에 미치는 효능(效能)에 대(對)한 비교(比較) 연구(硏究))

  • Kim, Kap-Sung
    • The Journal of Korean Medicine
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    • v.16 no.1
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    • pp.379-402
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    • 1995
  • This study was performed to investigate the comparative effects of Apitoxin(0.1% bee venom 0.1cc) & Acupuncture therapy on the knee joint arthritis induced by 0.1% carrageenin solution at Rt. knee joint in rats. After carrageenin injection, the apitoxin was injected for two times (Experimental group I : 1 & 24hours later, Experimental group II : 48 & 72hours later) into the corresponding loci to Rt. $ST_{35}$(Group 3) & $EX-LE_4$(group 4) of the human body in rats. Acupuncture therapy was done same as above. And then the comparative effects of apitoxin and acupuncture therapy on the knee joint arthritis were estimated by the WBC count, RBC count, hemoglobin level, hematocrit level and ASO titer in serum. The results were summerized as follows : 1. The effects of apitoxin & acupuncture on WBC count showed remarkable decrease at group 3 & group 4 as compared with the control group in both experimental group I & experimental group II. There were not any statistical difference from apitoxin and acupuncture therapy by Duncan's multiple range test. 2. The effect of apitoxin on RBC count showed noticeable decrease at group 3 & group 4 as compared with the control group in both experimental group I & experimental group II. The acupuncture was not showed decrease at group 3 & group 4 as compared with the control group in both experimental group I & experimental group II. There were not any statistical difference from apitoxin and acupuncture therapy by Duncan's multiple range test. 3. The effects of apitoxin & acupuncture on hemoglobin level showed noticeable decrease at group 3 & group 4 as compared with the control group in both experimental group I & experimental group II. There were not any statistical difference from apitoxin and acupuncture therapy by Duncan's multiple range test. 4. The effect of apitoxin on hematocrit level showed noticeable decrease at group 3 & group 4 as compared with the control group in both experimental group I & experimental group II. The acupuncture was not showed decrease at group 3 & group 4 as compared with the control group in both experimental group I & experimental group II. There were not any statistical difference from apitoxin and acupuncture therapy by Duncan's multiple range test. 5. The effect of apitoxin on ASO titer showed noticeable decrease at group 3 & group 4 as compared with the control group only in experimental group I. The apitoxin & acupuncture showed decrease at group 3 & group 4 as compared with the control group in experimental group II. There were significantly statistical difference from apitoxin and acupuncture therapy by Duncan's multiple range test. The effect of apitoxin showed slightly decrease as compared with the acupuncture therapy by Duncan's multiple range test.

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A Study on the Application of Simple Reliability Analysis for Soil Improvement (연약지반개량에 대한 신뢰성해석 간편법의 적용성 연구)

  • Jang, Yeon-Soo;Park, Joon-Mo
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.759-767
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    • 2009
  • Recently, there is a trend to introduce a reliability approach to the design of al large scale improvement of weak ground due to the uncertainty of the influence factors in the consolidation. Since the reliability analysis is not easily adopted to geotechnical engineers because of some difficulties in working up the theories, Duncan(2000) proposed a simplified method for using reliability method to goetechnical problems. In this study, the applicability of Duncan's simplified reliability approach is evaluated by comparing the traditional reliability results with Duncan's. In the sensitivity analysis, the two results were quite similar. However, the probability of failure showed an error range of 20~50% and further Duncan's approach could not make a distinction for the distribution of geotechnical random variables. The simplified reliability method seems to be used properly in preliminary design if it is used supplementary with the deterministic method.

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Sliding Knots and the Effect of Additional Half-Hitch Knots on Optimal Knot-Holding Capacity (체이동 매듭과 추가적인 반 매듭 증가에 따른 매듭의 장력 변화와 최적 유지력)

  • Hur, Chang-Yong;Kim, Seung-Ho;Kim, Byung-Kwan;Yoo, Jae-Chul
    • Journal of the Korean Arthroscopy Society
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    • v.8 no.1
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    • pp.37-44
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    • 2004
  • Purpose: To evaluate the optimal number of additional half hitches for achieving an optimal knot-holding capacity (KHC) of Lockable sliding knots. Methods: Four configurations of arthroscopic knots (Duncan loop, Field knot, Giant knot, and SMC knot) were tested for their knot-holding capacity. For each knot configuration, 6 sequential knots were made including the initial sliding knot and additional 5 knots by incrementing one half hitches at a time. Each added half-hitch were in reversing half-hitches with alternate posts (RHAPs) fashion. For each sequential knot configuration, 12 knots were made by No. 2 braided sutures. On the servo-hydraulic material testing system (Instron 8511, MTS, Minneapolis, MN), cyclic loading, load to clinical failure (3-mm displacement), load to ultimate failure, and mode of failure were measured. Results: Most of the initial loop without additional half-hitch showed dynamic failure with cyclic loading. The mean displacement after the end of cyclic loading decreased with each additional half-hitches. SMC and Giant knot reached plateau to 0.1 mm or less displacement after one additional half-hitch, shereas Field and Duncan loop needed 3 additional half-hitches. The SMC and Duncan knots needed 1 additional half-hitch to reach greater than 80N at clinical failure, whefeas the other 2 knots needed2 additional half-hitches. For the load exceeding 100N for clinical failure, the SMC knot required 3 additional half-hitches and the other three knots needed 4 additional half-hitches. As the number of additional half-hitches incremented, the mode of failure switched from pure loop failure (slippage) to material failure (breakage). Duncan loop showed poor loop security in that even with 5 additional half-hitches, some failed by slippage (17%). On the other hand, after 3 additional half-hitches, the 3 other knots showed greater than 75% of failure by material breakage mode (SMC and Field 92%, Giant 75%). Conclusion: Even with its own locking mechanism, lockable sliding knot alone does not withstand the initial dynamic cyclic load. For all tested variables, SMC knot requires a minimum of 2 additional half-hitches. Duncan knot may need more than 3 additional half-hitches for optimal security. All knots showed a mear plateau in knot security with 3 or more additional half-hitches.

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A Study of the Body Development of Infant and Child (유유아의 월령에 따른 신체 발달 연구 -12개월에서 59개월을 대상으로-)

  • 최유경;이순원
    • Journal of the Korean Society of Clothing and Textiles
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    • v.19 no.5
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    • pp.790-800
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    • 1995
  • This study was done to provide basic data for better fittness of infants and children's clothes and to get the developmental aspect of the subjects. The subjects were total 610 infants and children, 302 boys and 308 girls between month 12 to 59. 67 dependent variables were analyzed by the method of Duncan Test as Multiple Range Test among 8 groups anti T-test between male and female of same age groups. Following results were obtained: 1. In Duncan Test of the direct measurement items, the most subjects between group 1 and 8 were significantly different in the majority of dependent varibles, especially in height and length items 2. In Duncan Test of the body indices, as the subjects 'ages are higher, their bodies were balanced with the growth of the girth of their lower body. 3. In T-test, the significant difference between male and female of same month group was appeared mainly from 4th group to 7th group.

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The Relationship among Land Use, Vegetation and Surface Temperature in Urban Areas -The Case of Deagu City- (도시지역 지표온도와 토지이용 및 식생상태와의 상관관계에 관한 연구 : 대구광역시의 경우)

  • Kim, Jae Ik;Yeo, Chang-Hwan
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.2
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    • pp.21-30
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    • 2005
  • The primary purpose of this paper is to prove a clear relationship among land use type, vegetation level and surface temperature. For this purpose, this paper presents series of spatial distribution maps of the three features obtained through the visual interpretation of digital images. The result of study tells us that the spatial distribution of the vegetation level is very similar with that of surface temperature. By analyzing the relationship between surface temperature and land use types, this study categorizes the eighteen urban land uses into 7-8 groups according to their average surface temperature. The Duncan test was conducted to categorize the land uses. The surface temperature of manufacturing related land use is the highest, semi-residential use is the next, non-residential land use is the next to the lowest, and the agricultural and forest land use is the lowest. This paper provides another strong evidence of the relationship by showing the regression result.

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Study on the mechanical properties test and constitutive model of rock salt

  • Zhao, Baoyun;Huang, Tianzhu;Liu, Dongyan;Liu, Yang;Wang, Xiaoping;Liu, Shu;Yu, Guibao
    • Geomechanics and Engineering
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    • v.18 no.3
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    • pp.291-298
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    • 2019
  • In order to study the mechanical properties of rock salt, triaxial compression tests under different temperatures and confining pressure are carried out on rock salt specimens, the influence of temperature and confining pressure on the mechanical properties of rock salt was studied. The results show that the temperature has a deteriorative effect on the mechanical properties of rock salt. With the increase of temperature, the peak stress of rock salt decreases visibly; the plastic deformation characteristics become much obvious; the internal friction angle increases; while the cohesion strength decreases. With the increase of confining pressure, the peak stress and peak strain of rock salt will increase under the same temperature. Based on the test data, the Duncan-Chang constitutive model was modified, and the modified Duncan-Chang rock salt constitutive model considering the effect of temperature and confining pressure was established. The stress-strain curve calculated by the modified model was compared with the stress-strain curve obtained from the test. The close match between the test results and the model prediction suggests that the modified Duncan-Chang constitutive model is accurate in describing the behavior of rock slat under different confining pressure and temperature conditions.

Favorable Colors on the Facial Color Types of Korean Adult Females (한국 여성의 얼굴 피부색 유형에 어울리는 색채에 대한 연구)

  • Kim Ku-Ja
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.6
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    • pp.971-980
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    • 2006
  • The colors of apparel have a close relationship with the facial color types of consumers. To extract the favorable colors that flatter to consumer's facial color types, the facial colors of Korean females were analyzed. With color meter JX-777, 2 points of face were measured and classified into 3 clusters that had similar hue, value and chroma. Other new 10 college girls were measured and 3 subject among them were selected by the criteria that choose new subjects who have the classified facial color types. 175 respondents answered the degree of becomingness of color samples on three subjects. Data were analyzed by K-means cluster analysis, ANOVA and Duncan multiple range test using SPSS Win. 12. Findings were as follows: 1) 324 subjects who had YR facial colors were classified into 3 facial color groups. The average facial color Type 1 was 4.82YR 6.47/3.70 and composed 48.88% among total observations. Type 2 was 5.99YR 6.12/4.12 and 30.25%. Type 3 was 5.15YR 7.07/4.97 and 20.99% respectively. 2) Favorable colors for Type 1 were 18 colors that belonged to 'a' group from among colors that were divided into a, b, c group by Duncan post hoc test. 3) Type 2 showed that this type had many unfavorable colors. Unfavorable colors were 18 colors that belonged to 'c' by Duncan test. 4) Type 3 showed that black is the most favorable color and 18 colors were at middle level, which belonged to 'b' from among 18 colors that were divided into a, b, and c by Duncan test.

Clustering of Facial Color Types and Their Favorable Colors on Korean Adult Males (한국 남성의 얼굴 피부색 분류와 유형에 어울리는 색채 연구)

  • Kim, Ku-Ja
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.2
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    • pp.316-325
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    • 2006
  • The colors of apparel are getting more important to give the differentiated character on fiber and fabrics. This study was to extract the favorable colors that become to facial color types. Research was carried out to classify the facial colors into several similar facial color groups. With JX-777, 2 points of face: forehead and cheek, were measured and classified into 3 facial color types. Sample size was 418 Korean adult males and other 15 of new males subjects. New chosen 3 subjects who had the classified facial color types, wore silver gown and black hat on his head to minimize the interaction of the clothe color an hair. The 40 standardized color samples were used to extract the favorable colors. 187 respondents answered the degree of becomingness of color samples on 3 facial color types. Data were analyzed by K-means cluster analysis, ANOVA and Duncan multiple range test using SPSS Win. 12. Findings were as follows: 1. 418 subjects who had YR colors were classified into 3 kinds of facial color groups. Type 1 was 4.59YR 5.89/5.12, Type 2 was 5.61 YR 5.41/4.79 and Type 3 was 4.38YR 6.49/4.89 respectively. 2. Favorable colors for Type 1 were 2 colors that belonged to ' a ' group from among colors that were divided into a, b, c group and 18 colors that belonged to ' a ' group from among colors that were divided into a, b group by Duncan post hoc test. 3. Type 2 showed that this type had many unfavorable colors. Unfavorable colors were 16 colors that belonged to ' c ' by Duncan test. 5. Favorable colors for Type 3 were 14 colors that belonged to ' a ' from among colors that were divided into a, b, c and 16 colors that belonged to ' a ' from among colors that were divided into a, b by Duncan test.