Detection of DNA Methylation Changes during Somatic Embryogenesis of Siberian Ginseng (Eleuterococcus senticosus)

Debasis Chakrabarty,Kee-Won Yu(유기원),Kee Yoeup Paek(백기엽) 한국원예학회 2002 한국원예학회 학술발표요지 Vol.2002 No.6

범용 Hoek-Brown 파괴기준식의 직접 및 간접적 적용에 관한 수치해석과정의 비교 분석

Debasis Deb,최성웅 한국암반공학회 2005 터널과지하공간 Vol.15 No.3

Friction angle and cohesion of rock masses can be estimated from Hoek and Brown failure criterion and then plastic corrections can be applied using Mohr-Coulomb yield function. This study finds that this estimation procedure would not be appropriate for weak rock masses and for cases where low confining stress is expected to develop. A procedure is outlined in this paper for estimating plastic corrections directly from Hoek and Brown material model. Comparative study shows that direct procedure would simulate non-linear failure surface better than indirect procedure especially in the low confining stress regime.KeyWords Hoek and Brown failure criterion, Mohr-Coulomb yield function, plastic correction, direct procedure, indirect procedure Hoek-Brown의 파괴기준식으로부터 암반의 내부마찰각 및 점착강도를 계산한 후, Mohr-Coulomb의 항복함수를 이용하여 소성 보정이 적용될 수 있는 것으로 알려져 있다. 하지만 본 연구에서는 이러한 계산 과정이 연약 암반이나 낮은 봉압 조건의 암반에 대해서는 적합하지 않다는 사실을 보여주고자 한다. 즉, Hoek-Brown 재료 모델로부터 직접 및 간접적 적용에 의해 소성 보정을 수행하는 과정을 제시하였으며, 이를 통해 직접적 적용이 간접적 적용에 비해, 비선형 파괴면을 더욱 효과적으로 모사할 수 있고, 특히 봉압이 낮은 응력 조건에서 효과적임을 보여주고자 한다.

Physiological Genomic Approach to Access the Anti-metabolic Syndrome Potential of a Novel Calcium/Potassium Salt of [-]-Hydroxycitric Acid [HCA-SX]

Debasis Bagchi 한국식품영양과학회 2010 한국식품영양과학회 산업심포지움발표집 Vol.2010 No.1

Comparison between Direct and Indirect Implementation of Generalized Hoek and Brown Failure Criterion in Numerical Analysis Procedure

Debasis Deb,Sung O. Choi(최성웅) 한국암반공학회 2005 터널과지하공간 Vol.15 No.3

Hoek-Brown의 파괴기준식으로부터 암반의 내부마찰각 및 점착강도를 계산한 후, Mohr-Coulomb의 항복함수를 이용하여 소성 보정이 적용될 수 있는 것으로 알려져 있다. 하지만 본 연구에서는 이러한 계산 과정이 연약 암반이나 낮은 봉압 조건의 암반에 대해서는 적합하지 않다는 사실을 보여주고자 한다. 즉, Hoek-Brown 재료 모델로부터 직접 및 간접적 적용에 의해 소성 보정을 수행하는 과정을 제시하였으며, 이를 통해 직접적 적용이 간접적 적용에 비해, 비선형 파괴면을 더욱 효과적으로 모사할 수 있고, 특히 봉압이 낮은 응력 조건에서 효과적임을 보여주고자 한다. Friction angle and cohesion of rock masses can be estimated from Hoek and Brown failure criterion and then plastic corrections can be applied using Mohr-Coulomb yield function. This study finds that this estimation procedure would not be appropriate for weak rock masses and for cases where low confining stress is expected to develop. A procedure is outlined in this paper for estimating plastic corrections directly from Hoek and Drown material model. Comparative study shows that direct procedure would simulate non-linear failure surface better than indirect procedure especially in the low confining stress regime.

Hyperhydricity: Ultrastuctural and Physiological Aspects

Debasis Chakrabarty,So-Young Park(박소영),Kong-Sik Shin(신공식),Kee-Yoeup Paek(백기엽) 한국원예학회 2002 한국원예학회 학술발표요지 Vol.2002 No.6

Analysis of Sinkhole Formation over Abandoned Mine using Active-Passive-Active Finite Elements

Debasis Deb,Sung O. Choi(최성웅),Hee-Soon Shin(신희순) 한국암반공학회 2004 터널과지하공간 Vol.14 No.6

폐광지역에서 흔히 발생하는 싱크홀 형태의 지반침하는 인근 지역 주민의 안전은 물론, 지상구조물에 심각한 위해 요소로 작용할 수 있다. 본 연구에서는, 이러한 싱크홀의 발생양상을 수치해석적으로 규명하기 위해, 아주 특별한 형태의 유한요소해석을 실시하였다 특히, 갱도 천반의 붕락에 의해 야기되는 공간이나, 파쇄된 암반이 쌓여서 이루는 폐석더미 등 기존의 수치해석기법으로서는 쉽사리 표현할 수 없었던 현실적인 문제들을 수치적으로 모사하기 위해 active-passive-active 유한요소를 사용하였다. Active 요소 즉 고체 요소는 싱크홀이 형성되는 영역 내에서 인장파괴 기준식을 만족하게 되면 passive 요소 즉 공간 요소로 전환될 수 있다. 싱크홀이 완전히 형성되게 되면 이들 passive 요소들은 다시 active 요소로 바뀌면서 폐석더미를 수치적으로 모사할 수 있게 된다. 채굴적의 폭, 심도 천반의 상태 및 붕락 암반의 부피팽창율 등이 싱크홀에 미치는 영향을 검토하기 위해 여러 가지 조건에 의한 유한요소모델이 해석되었다. 본 연구는, 이와 같이 싱크홀이 발생하는 과정이나 천반이 붕락하는 현상 등을 해석하기 위해 수치해석상에서 active-passive-active 유한요소들이 효과적으로 사용될 수 있음을 보여준다. Sinkhole subsidence occurs over abandoned mine workings and can be detrimental to human lives, damage to properties and other surface structures. In this study, simulation of sinkhole development process is performed using special finite element procedure. Especially, creation of mine voids due to roof falls and generation of goaf from broken rocks are simulated using active-passive-active finite elements. An active or solid element can be made passive or void once the tensile failure criterion is satisfied in the specified sinkhole formation zone. Upon completion of sinkhole development process, these passive elements can again be made active to simulate goaf region. Several finite element models are analyzed to evaluate the relationships between sinkhole formation with width of gallery, depth of mine, roof condition and bulking factor of roof rocks. This study demonstrates that the concept of passive elements in numerical analysis can be used effectively for analyzing sinkhole formation or roof fall phenomenon in general.

In vitro regeneration and plantlet formation from adventitious roots of Rehmannia glutinosa

Debasis Chakrabarty,Kee Won Yu,Kee Yoeup Paek,Jae Hun Jeong,Sun Ja Kim 한국육종학회 2001 한국육종학회 학술발표회 발표요지 Vol.2001 No.9

In vitro Meristem Tip Culture of Rosa hybrida

Debasis Chakrabarty,Subodh Kumar Datta 한국원예학회 2006 Horticulture, Environment, and Biotechnology Vol.47 No.2

A micropropagation method for Rosa hybrida cv. Contempo and Mrinalini is presented using shoot tip proliferation onto Murashige and Skoog (MS) medium with 0.2 ㎎ㆍL?¹ indole-3-acetic acid (IAA) along with different concentrations of 6-benzylaminopurine (BAP). Percent of explant producing multiple shoots, number of shoots per responded explant and growth of shoots varied with BAP concentration. The optimum results were recorded in 2 ㎎ㆍL?¹ BA. Addition of AgNO₃ in the medium reduced leaf abscission of the in vitro developed shoots. The regenerated plants were transferred to rooting medium (×1/4 MS with 0.1 ㎎ㆍL?¹ IAA, 0.1 ㎎ㆍL?¹ indole-3-butyric acid, 30 gㆍL?¹ sucrose, and 0.6% agar). The highest percentage of root formation was observed in ‘Contempo’ (57.1%), whereas very low percentage of rooting (16.6%) was observed in ‘Mrinalini’. When rooting medium was supplemented with different concentrations of activated charcoal, increase in rooting percentage with increasing the concentration was recorded in the case of ‘Mrinalini’. At the end of 21-28 days, however, the shoots were deteriorated due to yellowing of leaflets. When the plantlets were rooted in liquid medium, on the contrary, the percentage of yellowing leaflets was almost zero. The resulting plantlets were acclimatized and grown in potted soil where they developed normally.

Hyperhydricity: Stress related phenomenon?

Debasis Chakrabarty,Y. H. Dewir,M. B. Ali,E. J. Hahn(한은주),K.Y. Paek(백기엽) 한국원예학회 2005 한국원예학회 학술발표요지 Vol.2005 No.5

Monensin Enriched Urea Molasses Mineral Block on Feed Intake, Nutrient Digestibility and Blood Glucose in Cattle Fed on Wheat Straw Based Diet

De, Debasis,Singh, G.P. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.11

Twelve adult male crossbred (Sahiwal${\times}$Holstein Friesian) cattle were distributed into four groups of three each on body weight basis. Animals were given wheat straw as a basal diet. The animals of group I and II were supplemented with concentrate mixture and animals of group III and IV were supplemented with cold processed urea molasses mineral block (UMMB). Thirty mg monensin/day/animal was supplemented to the animals of group II and 35 ppm monensin were incorporated in the UMMB supplemented to the animals of group IV. Vit.A and D mixture was given to all the animals once a week. Dry matter (DM) intake (kg/d) through wheat straw was 19.0 percent higher in the UMMB (without monensin) supplemented group (group III) than those of the concentrate mixture (without monensin) supplemented group i.e. group I. Total DM intake (kg/d) was lower in the monensin supplemented groups than those of non-supplemented groups though differences were not statistically significant. Digestible dry matter, organic matter (OM), crude protein (CP) and total digestible nutrients (TDN) intake were similar in all the groups. Average block consumption for 45 d period in the group III (0.95 kg/d) and group IV (0.84 kg/d) did not differ significantly. DM digestibility (%) was significantly (p<0.01) higher in the group II (58.9) as compared to the group I (52.7) and group III (54.0) but similar to the group IV (57.2). OM digestibility was also significantly (p<0.05) higher in the group II (63.2) as compared to that of the group I (54.9) but similar to the group III (57.8) and IV (59.2). Ether extract (EE) digestibility was significantly (p<0.01) higher in the group I (76.9) and II (80.3) as compared to the group III (59.87) and IV (55.77). Nitrogen free extract (NFE) digestibility was significantly (p<0.05) higher in the group II (62.38) as compared to that of the other groups. Crude protein (CP) and crude fibre (CF) digestibilities were not affected either due to UMMB or monensin. Nitrogen balance did also not differ significantly among the groups. However, Ca and P balance (g/d) in the group III (3.1, 1.3) and IV (3.0, 1.4) were significantly (p<0.01) higher than those of the group I (0.6, 0.2) and II (0.4, 0.3). Blood glucose (mg/100ml) was significantly (p<0.01) higher in the group II (65.2) and IV (65.2) as compared to the group I (55.2) and group III (53.9). Plasma urea-N level (mg/100 ml) in the group III (19.0) and IV (17.8) were significantly (p<0.01) higher than that of the group I (10.5) and II (12.3). So, monensin supplementation either with cold process UMMB or concentrate mixture did not show any additional effect on feed intake and digestibility but increases blood glucose level in adult cattle.