859 research outputs found

    Reactive Extraction of Citric Acid Using Different Extractants: Equilibrium, Kinetics and Modeling

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    Recovery of citric acid from biotechnologically produced low concentration aqueous solution has attracted several separation techniques for the downstream processing. Amongst them, reactive extraction is a convenient, cheap, and effective method. Three different extractants are used in this study, namely tri-n-butyl phosphate (TBP), tri-n-octylamine (TOA), and Aliquat 336 (A336), all diluted in methyl-iso-butyl ketone (MIBK). The isothermal batch experiments were performed for the equilibrium and kinetic studies at T = 300.15±1 K. Around 92 % extraction efficiency (E %) was obtained using 20 % (v/v) TOA in MIBK. Based on the overloading of amine (Z > 0.5), (2:1) acid:extractant complex in TOA+MIBK phase was proposed. Kinetics of extraction of citric acid (0.2–0.8 kmol m–3) was also performed in a Lewis-type stirred cell, using TOA in MIBK. The extraction reaction was occurring in the diffusion film. The second order rate constant was calculated as k2 = 0.0351 m3 kmol–1 s–1. The extraction parameters were estimated by differential evolution optimization technique. Optimal value of equilibrium constant, KE, was found to be 3.6 · 10–3 (m3 kmol–1)2, for the reactive extraction of citric acid using 20 % TOA in MIBK, and was found in close agreement with experimental values. This work is licensed under a Creative Commons Attribution 4.0 International License

    Study of hyperfragments. Part V. Analysis of light hyperfragments

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    464 non-mesic and 65 mesic decay of hyperfragments (HFs) produced by pions of momenta 3·5 GeV/c. and 17·2 GeV/c. and protons of momentum 23 GeV/c., have been used to obtain information on Q-, the ratio of non-mesic to π- mesic events and S, the ratio of neutron to proton stimulated events as a function of charge of HFs. Q- is found to increase rapidly with the increase in charge of HFs; the value of Q- for HFs of Z≥3 is 14·6±3·0 which is high compared to the theoretical value of about 4 to 5. The value of S is found to be >1 for all HFs of Z≥2

    Yield Stability in Pigeon pea Hybrids [Cajanus cajan (L.) Millsp.] Under Varying Agro-Climatic Regions

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    Twelve pigeonpea genotypes comprising ten hybrids and two controls were evaluated at three environments during rainy season of 2012-13, to study genotype × environment interaction for yield and related traits. Analysis of variance in each environment and on a pooled basis expressed a significant difference among genotypes for yield and yield contributing characters except for 100 seed weight. Genotype × environment (linear) interactions were found significant for days to 50% flowering, plant height, primary and secondary branches per plant, pods per plant, seeds per pod, grain yield per plant and yield (kg/ha) except days to maturity and 100 seed weight. The regression and GGE biplot methods were used for analysis. Both methods identified ICPH 2671, ICPH 2740, ICPH 3933 and ICPH 3762 as stable hybrids. The GGE biplot explained higher proportion of the mean sum of squares of the G×E interaction and was more informative with regards to environments and their genotypic performance than the regression method. Hybrids ICPH 2671, ICPH 2740, ICPH 3762 and ICPH 3933 showed stability for the yield and yield components and could be recommended for cultivation

    The ratio of non-mesic to &#960;<SUP>-</SUP>-mesic decay of light hyperfragments

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    A new method of obtaining the charge spectrum of light hyperfragments from their residual range distribution is described. This method has been used to determine the ratio (Q-) of non-mesic to &#960;--mesic decay of light hyperfragments. The values of Q- for hyperfragments of different charges are found to be in good agreement with theoretical calculations of Dalitz

    Stability of Cytoplasmic Genetic Male Sterility and Fertility Restoration in Pigeonpea

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    In cytoplasmic genetic male sterility-based (CGMS) hybrid seed production, instability of expression of male-sterility and fertility restoration across a wide range of environments are two of the major difficulties. Therefore, the present study was carried out to investigate the stability of male sterility of nine CGMS lines under three dates of sowing and the fertility restoration of 10 CGMS-based pigeonpea ( Cajanus cajan (L.) Millsp.) hybrids at three different locations. Significant variability existed for pollen fertility among hybrids and sterility among cytoplasmic male sterile (CMS) lines. All the hybrids except ICPH 3494 and ICPH 3491 exhibited high (>80%) pollen fertility across locations. Hybrids ICPH 2671, ICPH 2740, and ICPH 3933 had 100% male-fertile plants across locations. All the CMS lines had completely male-sterile plants across sowing dates. The CMS lines BRG1 A, Hy3C A, BRG3 A, and TTB7 A exhibited 100% pollen sterility at different sowing dates. The pooled analysis revealed a significant genotype × environment interaction for pollen fertility and sterility. The genotypic main effect + GE (GGE) biplot of hybrids showed that hybrids ICPH 2671, 2740, 3933, and 3461 were stable for fertility restoration. With the exception of ICPA 2047 and ICPA 2051, all the CMS lines were highly stable with high mean performance and least distance from AEA (average environmental axis). Male-sterility in A4 cytoplasm was independent of environmental conditions. Different dates of sowing did not affect expression of male sterility of these CMS lines

    Binding energy and &#960;<SUP>+</SUP> decay of light hyperfragments

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    Binding energy values of hyperfragments from a sample of 541 uniquely identified mesic decays with mass numbers A=3 to 14 are presented. There does not seem to be any detectable difference in the binding energy value of &#923; in AH4 obtained from its two-body and three-body decay modes. Within statistical error, the binding energy values of &#923; in AH4 and AH4 are also the same. From a sample of 2&#960; + decay events of hyperfragments the branching ratio of AH4 decaying by &#960; + to &#960; - mode is found to be (1&#183;5&#177;1&#183;0)%

    Phenomenological BCS theory of the high-TcT_c cuprates

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    A BCS model characterized by a phenomenological pair potential with on-site (V0V_0), nearest (V1V_1), and next nearest (V2V_2) neighbour coupling constants, and an empirical quasiparticle dispersion taken from angle-resolved photoemission spectra is considered. The model can consistently explain the experimental data concerning the pair state of the hole doped cuprates. Three ingredients are required to make the interpretation possible: the existence of flat bands, a very small effective on-site repulsion, and a slightly dominating effective nnn attraction V2V_2 of the order of 60-80meV with a ratio V2/V11.5V_2/V_1 \approx 1.5.Comment: 13 pages, uuencoded Postscrip

    Phase transition from a dx2y2d_{x^2-y^2} to dx2y2+dxyd_{x^2-y^2}+d_{xy} superconductor

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    We study the phase transition from a dx2y2d_{x^2-y^2} to dx2y2+dxyd_{x^2-y^2}+d_{xy} superconductor using the tight-binding model of two-dimensional cuprates. As the temperature is lowered past the critical temperature TcT_c, first a dx2y2 d_{x^2-y^2} superconducting phase is created. With further reduction of temperature, the dx2y2+dxy d_{x^2-y^2}+d_{xy} phase is created at temperature T=Tc1T=T_{c1}. We study the temperature dependencies of the order parameter, specific heat and spin susceptibility in these mixed-angular-momentum states on square lattice and on a lattice with orthorhombic distortion. The above-mentioned phase transitions are identified by two jumps in specific heat at TcT_c and Tc1T_{c1}.Comment: Latex file, 5 pages, 6 postscript figures, Accepted in Physical Review
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