Synthesis, Structure and Characterization of Nd_2XCd_2-3XSiO₄ (0.01≤X≤0.21) Solid-Solutions

Ramesh, S.,Das, B.B. Korean Chemical Society 2011 대한화학회지 Vol.55 No.3

[ $Nd_{2x}Cd_{2-3x}SiO_4$ ]($0.01{\leq}x{\leq}0.21$) [S1-S3: x=0.01, 0.11 and 0.21] 고용체를 졸-겔 방법을 통해 합성하였다. X선 분말회절(XRD) 측정은 $P2_1$/m 공간군의 단사정계를 보여준다. 평균 결정 크기는 20-45 nm이다. 주사전자현미경(SEM)으로 살펴본 모양은 구형의 특성을 보인다. 에너지 분산 X 선 분광기(EDS) 결과로부터 모든 구성 원소의 존재를 확인하였다. ~750 nm에서의 흡수 밴드는 $Nd^{3+}$ 이온의 $^4I_{9/2}{\rightarrow}^4F_{7/2}+^4S_{3/2}$ 전이에 기인한다. 10, 40, 77, 300 K에서 S1-S3의 전자 상자성 공명 (EPR) 선모양은 $Nd^{3+}$ 이온의 빠른 스핀 격자 이완에 기인하는 폭이 넓은 구분되지 않은 등방성의 선모양을 보여준다. Synthesis of $Nd_{2x}Cd_{2-3x}SiO_4$ ($0.01{\leq}x{\leq}0.21$) [S1-S3: x=0.01, 0.11 and 0.21] solid solutions were prepared by solgel method. Powder x-ray diffraction (XRD) results show monoclinic unit cell with space group P21/m. The average crystallite sizes are found to be 20 to 45 nm. The Scanning Electron Microcopy (SEM) images show morphology of the sample is in globular nature. The energy dispersive analysis of x-rays (EDX) and X-ray mapping results confirmed that all the constituent elements of the composites were present and that were distributed in uniformly. The optical absorption band at ~750 nm was due to $^4I_{9/2}{\rightarrow}^4F_{7/2}+^4S_{3/2}$ transition optically active $Nd^{3+}$ ions. Electron Paramagnetic Resonance (EPR) lineshapes of S1-S3 at 10, 40, 77 and 300 K show a broad unresolved isotropic lineshapes were observed due to rapid spin lattice relaxation of $Nd^{3+}$.

Oxide Scale Characterization and Study of Oxidation Kinetics in T91 Steel Exposed to Dry Air at High Temperatures (873–1073 K)

S. Das,S. Sanyal,P. Halder,A. Varma,Y. Ravi Kumar,S. Mandal 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

In this study, the oxidation response of a T91 steel in dry air environment has been investigated by performing cyclic oxidationtests at 873, 973 and 1073 K for a total duration of 1000 h with intermediate intervals. The temperature range for thisstudy is chosen to be higher than the operating temperature range of the alloy to accelerate the oxidation kinetics. Developinga comprehensive understanding of the mechanisms and kinetics involved at such accelerated oxidation environmentswould help to formulate better strategies for countering oxidation related failure events. The results of this study showedthat the oxidation rate is greatly influenced by temperature as well as exposure time, and follows a near-parabolic rate law. Characterization of the oxide scales revealed formation of dual oxide layers where the inner layer is primarily rich in Feand Cr, and the outer layer in Fe only. At 1073 K, formation of cracks can be observed in the oxide scales after 24 h, whichbecame more severe after 1000 h. The oxidation kinetics, when fitted to an Arrhenius type equation, can be associated withactivation energy (Q) and parabolic rate constant (kp) values. The Q values lie within 104–109 kJ/mol, whereas the kp valuesincrease with temperature due to increase in the reaction rate. The kinetic equation developed based on the Q and kp valuescan be used to predict the thickness (inner, outer and overall) of the oxide scales in T91 steel at any temperature and timewithin the studied ranges.

Combinatorial expression of bacterial whole mevalonate pathway for the production of β-carotene in E. coli

Yoon, S.H.,Lee, S.H.,Das, A.,Ryu, H.K.,Jang, H.J.,Kim, J.Y.,Oh, D.K.,Keasling, J.D.,Kim, S.W. Elsevier Science Publishers 2009 Journal of biotechnology Vol.140 No.3

The increased synthesis of building blocks of IPP (isopentenyl diphosphate) and DMAPP (dimethylallyl diphosphate) through metabolic engineering is a way to enhance the production of carotenoids. Using E. coli as a host, IPP and DMAPP supply can be increased significantly through the introduction of foreign MVA (mevalonate) pathway into it. The MVA pathway is split into two parts with the top and bottom portions supplying mevalonate from acetyl-CoA, and IPP and DMAPP from mevalonate, respectively. The bottom portions of MVA pathway from Streptococcus pneumonia, Enterococcus faecalis, Staphylococcus aureus, Streptococcus pyogenes and Saccharomyces cerevisiae were compared with exogenous mevalonate supplementation for β-carotene production in recombinant Escherichia coli harboring β-carotene synthesis genes. The E. coli harboring the bottom MVA pathway of S. pneumoniae produced the highest amount of β-carotene. The top portions of MVA pathway were also compared and the top MVA pathway of E. faecalis was found out to be the most efficient for mevalonate production in E. coli. The whole MVA pathway was constructed by combining the bottom and top portions of MVA pathway of S. pneumoniae and E. faecalis, respectively. The recombinant E. coli harboring the whole MVA pathway and β-carotene synthesis genes produced high amount of β-carotene even without exogenous mevalonate supplementation. When comparing various E. coli strains - MG1655, DH5α, S17-1, XL1-Blue and BL21 - the DH5α was found to be the best β-carotene producer. Using glycerol as the carbon source for β-carotene production was found to be superior to glucose, galactose, xylose and maltose. The recombinant E. coli DH5α harboring the whole MVA pathway and β-carotene synthesis genes produced β-carotene of 465mg/L at glycerol concentration of 2% (w/v).

Relationship of Nitrate Reductase Activity to Leaf Yield, Protein, Sugar and Physiological Attributes in Mulberry (Morus alba L.)

Ghosh, M.K.,Das, B.K.,Das, C.,Mishra, A.K.,Mukherjee, P.K.,Urs, S.Raje Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.8 No.1

Ten improved mulberry varieties (Vl, C1730, C2016, C2017, Anantha, RFS-175, Thallaghatapura, Vishala, S1 and S1635) were evaluated through enzyme assay and estimation of soluble protein content followed by regression analysis, grown under irrigated conditions in the alluvial soils of Gangetic plains of West Bengal in India for five successive crops in a year, The nitrate reductase (EC No. 1.6.6.1) activity (NRA, $\mu$mol N $O_2$- $h^{-1}$ $g^{-1}$ fr, wt.), total soluble protein (mg $g^{-1}$ fr, wt.) was estimated which showed to vary significantly in the tested varieties. In addition to these, the other parameters like unit leaf fresh and dry weight (g), moisture %, unit leaf area ($\textrm{cm}^2$), specific leaf weight (g c $m^{-2}$ ), total soluble sugar (mg $g^{-1}$ fr, wt.), leaf yield/plant (kg), shoot yield/plant (kg) and net photosynthetic rate (NPR, $\mu$㏖ $m^{2}$ $s^{-1}$ ) were also studied which showed to vary significantly in tested varieties. Among them, S1635, haying higher NRA (13.25 $\mu$㏖ N $O_2$- $h^{-l}$ $g^{-1}$ fr, wt.), total soluble protein (39.63mg $g^{-1}$ fr, wt.), NPR(16.66 $\mu$㏖ $m^{-2}$ $s^{-1}$ ), total soluble sugar (48.44 mg $g^{-1}$ fr. wt.), leaf yield/plant (0.689 kg) and shoot yield/plant (1.135 kg) showed its superiority over other tested varieties. Regression and correlation coefficients were analysed, and a strong positive correlation was found between NRA & total soluble protein, NRA & NPR, NRA & total soluble sugar, NRA af unit leaf weight, NRA & specific leaf weight, NRA & leaf yield/plant, NRA & shoot yield/plant, NPR & leaf yield and NPR & specific leaf weight.t.

Relationship of Nitrate Reductase Activity to Leaf Yield, Protein, Sugar and Physiological Attributes in Mulberry (Morus alba L.)

M. K. Ghosh,B. K. Das,C. Das,A. K. Mishra,P. K. Mukherjee,S. Raje Urs 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.1

Ten improved mulberry varieties (V1, C1730, C2016, C2017, Anantha, RFS-175, Thallaghatapura, Vishala, S1 and S1635) were evaluated through enzyme assay and estimation of soluble protein content followed by regression analysis, grown under irrigated conditions in the alluvial soils of Gangetic plains of West Bengal in India for five successive crops in a year. The nitrate reductase (EC No. 1.6.6.1) activity (NRA, mmol NO2 - h-1g-1 fr. wt.), total soluble protein (mg g-1 fr. wt.) was estimated which showed to vary significantly in the tested varieties. In addition to these, the other parameters like unit leaf fresh and dry weight (g), moisture%, unit leaf area (cm2), specific leaf weight (g cm-2), total soluble sugar (mg g-1 fr. wt.), leaf yield/plant (kg), shoot yield/plant (kg) and net photosynthetic rate (NPR, mmol m-2 s-1) were also studied which showed to vary significantly in tested varieties. Among them, S1635, having higher NRA (13.25 mmol NO2 - h-1g-1 fr. wt.), total soluble protein (39.63 mg g-1 fr. wt.), NPR (16.66 mmol m-2 s-1), total soluble sugar (48.44 mg g-1 fr. wt.), leaf yield/plant (0.689 kg) and shoot yield/plant (1.135 kg) showed its superiority over other tested varieties. Regression and correlation coefficients were analysed, and a strong positive correlation was found between NRA & total soluble protein, NRA & NPR, NRA & total soluble sugar, NRA & unit leaf weight, NRA & specific leaf weight, NRA & leaf yield/plant, NRA & shoot yield/plant, NPR & leaf yield and NPR & specific leaf weight.

GREY-FUZZY TAGUCHI APPROACH FOR MULTI-OBJECTIVE OPTIMIZATION OF PERFORMANCE AND EMISSION PARAMETERS OF A SINGLE CYLINDER CRDI ENGINE COUPLED WITH EGR

S. ROY,A. K. DAS,R. BANERJEE 한국자동차공학회 2016 International journal of automotive technology Vol.17 No.1

The present study attempts to address the challenges of the multiobjective optimization problem of the BSFCNOx- PM trade-off paradox of an existing diesel engine by harnessing the synergetic benefit of PM and BSFC reduction through CRDI operation and simultaneous NOx reduction by EGR application. Load, FIP and EGR were chosen as the input parameters while NOx, PM and BSFC were the response variables. In order to reduce the experimental effort, the Taguchi L16 orthogonal array technique was employed to obtain the corresponding values of the response variables. The grey relational analysis coupled with fuzzy logic has been employed as the optimization routine. The optimal combination of the input parameters corresponding to the calibrated values of the response variables were obtained by employing the Grey-Fuzzy Grade and S-N ratio strategy as a performance index. The computed optimal combination so obtained were further validated through actual experimentation. EGR was found to be the most influencing factor in the present optimization endeavour. The study also established that the Grey-Fuzzy-Taguchi method was not only comparable but superior to the Grey-Taguchi method usually employed for such optimization studies.

Developing Short Term Drought Severity-Duration-Frequency Curves for Kerala Meteorological Subdivision, India Using Bivariate Copulas

Adarsh S.,Karthik S.,Shyma M.,Prem G. Das,Shirin Parveen A. T.,Sruthi Narayan 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.3

Severity-duration-frequency (S-D-F) curve is a useful hydrological tool for drought mitigation. This paper presents a bivariate copula approach for developing SDF relationships for Kerala meteorological subdivision, India based on the three month standardized precipitation index (SPI-3). First the univariate models were developed considering Gamma and Weibull distributions to represent the probability of severity and duration of SPI-3 series of the subdivision prepared from the area weighted precipitation data. The joint association of these drought variables is modeled by three Archimedean copulas namely Clayton, Frank and Gumbel- Hougaard (GH). The results showed that the difference between the joint SDF relations with the type of copulas is marginal upto return period 100 (~) whereas the conditional dependency of drought variables showed distinct differences. The conditional SDF relationships between severity and return period showed larger differences for longer duration and the behaviour is identical in the relationships between duration and return period for conditional severity values. Further, to outline the spatial variability of short term drought, a detailed examination on SDF relations of different districts in Kerala is made by considering representative fine resolution gridded rainfall (0.25o × 0.25o) datasets. SDF relationships of different locations in Kerala showed a shorter duration drought of less severity magnitude is prominent in districts like Wayanad, Kottayam and Pathanamthitta. The highest value of equilibrium severity for longer drought duration for all return periods is noticed for Palakkad while lowest value is observed for the district of Wayanad, which are the two low rainfall regions of the subdivision.

Relationship of Nitrate Reductase Activity to Leaf Yield, Protein, Sugar and Physiological Attributes in Mulberry (Morus alba L.)

( M. K. Ghosh ),( B. K. Das ),( C. Das ),( A. K. Mishra ),( P. K. Mukherjee ),( S. Raje Urs ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.1

Ten improved mulberry varieties (Vl, C1730, C2016, C2017, Anantha, RFS-175, Thallaghatapura, Vishala, S1 and S1635) were evaluated through enzyme assay and estimation of soluble protein content followed by regression analysis, grown under irrigated conditions in the alluvial soils of Gangetic plains of West Bengal in India for five successive crops in a year. The nitrate reductase (EC No. 1.6.6.1) activity (NRA, μmol NO2-h-1 g-1 fr, wt.), total soluble protein (mg g-1 fr, wt.) was estimated which showed to vary significantly in the tested varieties. In addition to these, the other parameters like unit leaf fresh and dry weight (g), moisture %, unit leaf area (㎠), specific leaf weight (g ㎝-2), total soluble sugar (mg g-1 fr, wt.), leaf yield/plant (kg), shoot yield/plant (kg) and net photosynthetic rate (NPR, μ㏖ m-2 g-1) were also studied which showed to vary significantly in tested varieties. Among them, S1635, haying higher NRA (13.25 μ㏖ NO2-h-1g-1 fr, wt.), total soluble protein (39.63 mg g-1 fr, wt.), NPR (16.66 μ㏖ m-2 S-1), total soluble sugar (48.44 mg g-1 fr. wt.), leaf yield/plant (0.689 kg) and shoot yield/plant (1.135 kg) showed its superiority over other tested varieties. Regression and correlation coefficients were analysed, and a strong positive correlation was found between NRA & total soluble protein, NRA & NPR, NRA & total soluble sugar, NRA & unit leaf weight, NRA & specific leaf weight, NRA & leaf yield/plant, NRA & shoot yield/plant, NPR & leaf yield and NPR & specific leaf weight.

Use of a Mexican lime (Citrus aurantifolia Swingle) edible coating to preserve minimally processed mango (Mangifera indica L)

Daniela Sánchez Aldana,Cristobal Noé Aguilar,Juan Carlos Contreras-Esquivel,Marthyna Pessoa Souza,Maria das Graças Carneiro-da-Cunha,Guadalupe Virginia Nevárez-Moorillón 한국원예학회 2021 Horticulture, Environment, and Biotechnology Vol.62 No.5

This work aimed to develop an edible coating based on Mexican lime ( Citrus aurantifolia Swingle) pectic extract and essentialoil on Haden mango ( Mangifera indica L.) to extend its shelf life. Mango cubes were coated by immersion in a lime pecticextract (1% pectin w/v), lime essential oil (0.05% v/v), and glycerol (0.7% v/v) solution for 2, 5, and 10 min. Subsequently,coated and uncoated (control) test samples were stored for 21 days, and physical–chemical and microbiological analyseswere performed every 3 days. The results showed no signifi cant diff erences for total soluble solids, pH, and fi rmness. On thesixth day, bacterial growth was signifi cantly lower in coated mangos than in the control (log 6.08 ± 0.49 and 7.63 ± 0.20 UFCg −1 , respectively). The application of the edible coating extended the shelf life of minimally processed mangos by 3 days,delaying physical and chemical changes as well as bacterial growth.

Anthelmintic activity of $Clerodendrum$ $viscosum$

Das, Jayanta Kumar,Choudhury, S.,Adhikary, S.,Das, B.,Samanta, S.,Mandal, S.C.,Dey, S.P. 경희한의학연구센터 2011 Oriental Pharmacy and Experimental Medicine Vol.11 No.2

The juice of the fresh leaves of $Clerodendrum$ $viscosum$ is widely used in the treatment of helminthiasis in folklore medicine. In this present study we have investigated the folklore claim methodically and scientifically. The ethanolic and aqueous extracts of leaves and roots of the plant are tested against $Pheretima$ $posthuma$ & $Ascardia$ $galli$ to ascertain their anthelmintic potential. All the extracts showed significant anthelmintic activity in dose dependent manner; the ethanolic extract of root at a dose of 200 mg/ml exhibited better anthelmintic activity than the reference drug, Piperazine citrate (10 mg/ml) against both type of worms.