997 resultados para transient absorption-spectrocospy


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Abstract is not available.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Two key quality traits in milling wheat are flour yield (FY) and water absorption (WA). Ideally, breeders would prefer to use markers to select promising lines rather than time consuming rheology tests. In this study, we measured FY and WA on a wheat mapping population (Lang/QT8766) of 162 individuals grown in two replicated field experiments at three locations over 2 years. We also carried out near infrared reflectance spectroscopy (NIRS) predictions on the grain for these traits to see if NIRS phenotypic data could provide useful mapping results when compared to the reference phenotypic data. Several common QTLs were identified for FY and WA by both sets of data. The QTL on chromosome 4D was a consistently recurring QTL region for both traits. The QTL on chromosome 2A was positively linked to protein content which was supported by genetic correlation data. The results also indicated it was possible to obtain useful phenotypic data for mapping FY and WA using NIRS data. This would save time and costs as NIRS is quicker and cheaper than current rheology methods.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

An analysis of gas absorption accompanied by chemical reaction in the presence of interfacial resistance is presented. The analysis indicates that the effect of interfacial resistance on interphase mass transfer is significantly higher in presence of a reaction compared to the pure absorption case. For fixed values of surface resistance and contact time, the difference between the amount of gas transferred across the interface with and without surface resistance increases as the value of reaction velocity increases. For ranges of contact time and surface resistance of practical relevance, the influence of surface resistance is too high to be neglected while designing gas-liquid contactors.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper a method of solving certain third-order non-linear systems by using themethod of ultraspherical polynomial approximation is proposed. By using the method of variation of parameters the third-order equation is reduced to three partial differential equations. Instead of being averaged over a cycle, the non-linear functions are expanded in ultraspherical polynomials and with only the constant term retained, the equations are solved. The results of the procedure are compared with the numerical solutions obtained on a digital computer. A degenerate third-order system is also considered and results obtained for the above system are compared with numerical results obtained on the digital computer. There is good agreement between the results obtained by the proposed method and the numerical solution obtained on digital computer.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Several alkylidene malononitriles (1b,1d,1e,2b and4b) and alkylidene cyanoacetates (1a,2a and4a) studied exhibit a long wavelength UV absorption band around 355 nm which shows a hyperchromic effect in the presence of ethanolic alkali. This band has been assigned to the ketenimine tautomer (5). Addition of water to1b,1e and2b gives the corresponding pyridine diols (7a,7b and8a) respectively. Similarly, addition of ethanol to1e and2b gave the corresponding ethoxypyridine derivatives (7c and8b). Mechanism of formation of these compounds is discussed. Structures, as well as mechanism of formation of1c,7c and10 obtained from1b,1e and2b respectively on standing at room temperature are also discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Several alkylidene malononitriles (1b,1d,1e,2b and4b) and alkylidene cyanoacetates (1a,2a and4a) studied exhibit a long wavelength UV absorption band around 355 nm which shows a hyperchromic effect in the presence of ethanolic alkali. This band has been assigned to the ketenimine tautomer (5). Addition of water to1b,1e and2b gives the corresponding pyridine diols (7a,7b and8a) respectively. Similarly, addition of ethanol to1e and2b gave the corresponding ethoxypyridine derivatives (7c and8b). Mechanism of formation of these compounds is discussed. Structures, as well as mechanism of formation of1c,7c and10 obtained from1b,1e and2b respectively on standing at room temperature are also discussed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

IR absorption spectra of As-Se glasses have been studied over a wide range of compositions. Various two-phonon, multiphonon (combination tones) and impurity absorptions have been identified. Compositional variation of relative band intensities has been explained in terms of the chemically ordered network model.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

X-ray absorption edge and X-ray photoelectron spectroscopic studies of As-Se glasses seem to support a chemical ordering model.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

1. The mechanism of absorption of phosphatidylcholine was studied in rats by injecting into the intestine phosphatidylcholine specifically labelled either in the fatty acid or in the glycerol moiety or with 32P, when considerable amounts of 1-acyl-lysophosphatidylcholine were found in the intestinal lumen. 2-([14C]Acyl)phosphatidylcholine gave markedly more radioactive unesterified fatty acids in the lumen, compared with the 1-([14C]acyl) derivative. Some of the radioactivity from either the fatty acid or the glycerol moiety of the injected phosphatidylcholine appeared in the mucosal triacylglycerols. 2. Injection of 32P-labelled phosphatidylcholine or 32P-labelled lysophosphatidylcholine led to the appearance of radioactive glycerylphosphorylcholine, glycerophosphate and Pi in the mucosa. 3. Rat mucosa was found to contain a highly active glycerylphosphorylcholine diesterase. 4. It was concluded that the dietary phosphatidylcholine is hydrolysed in the intestinal lumen by the pancreatic phospholipase A to 1-acylglycerylphosphorylcholine, which on entering the mucosal cell is partly reacylated to phosphatidylcholine, and the rest is further hydrolysed to glycerylphosphorylcholine, glycerophosphate, glycerol and Pi. The fatty acids and glycerophosphate are then reassembled to give triacylglycerols via the Kennedy (1961) pathway.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

On interrupting polarisation, the magnesium anode exhibits a negative overshoot in potential followed by a slow recovery to a steady state value. A model has been proposed to explain the opencircuit potential-time transient in terms of a spontaneous passivation of the metal and the consequent changes in the corrosion potential. Theoretical expressions have been derived for the timedependence of the open-circuit electrode potential. Calculated, potential-time curves thus obtained are in qualitative agreement with experimental data. A possible application of this phenomenon to develop non-destructive quality control tests of Mg, Li and Al-based dry cells has been pointed out.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mixed valency in CePd3 has been examined by a study of the LIII (Ce) absorption edge in this compound as well as other model compounds. In CePd3, peaks characteristic of 3+ and 4+ states of Ce are found to be separated by 2 eV.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper deals with an approximate method of analysis of non-linear, non-conservative systems of two degrees of freedom. The approximate equations for amplitude and phase are obtained by a generalized averaging technique based on the ultraspherical polynomial approximation. The method is illustrated by an example of a spring-mass-damper system.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper the response of a gyrostabilized platform subjected to a transient torque has been analyzed by deliberately introducing non-linearity into the command of the servomotor. The resulting third-order non-linear differential equation has been solved by using a transformation technique involving the displacement variable. The condition under which platform oscillations may grow with time or die with time are important from the point of view of platform stabilization. The effect of deliberate addition of non-linearity with a view to achieving the ideal response—that is, to bring the platform back to its equilibrium position with as few oscillations as possible—has been investigated. The conditions under which instability may set in on account of the small transient input and small non-linearity has also been discussed. The analysis is illustrated by means of a numerical example. The results of analysis are compared with numerical solutions obtained on a digital computer.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Due to the advent of varied types of masonry systems a comprehensive failure mechanism of masonry essential for the understanding of its behaviour is impossible to be determined from experimental testing. As masonry is predominantly used in wall structures a biaxial stress state dominates its failure mechanism. Biaxial testing will therefore be necessary for each type of masonry, which is expensive and time consuming. A computational method would be advantageous; however masonry is complex to model which requires advanced computational modelling methods. This thesis has formulated a damage mechanics inspired modelling method and has shown that the method effectively determines the failure mechanisms and deformation characteristics of masonry under biaxial states of loading.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

1. The biopotencies relative to beta-carotene of several apocarotenoids, such as 8'-, 10'- and 12'-apo-beta-carotenal and methyl 8'-apo-beta-carotenoate, were investigated in rats, on a molar basis, by both curative-growth assay and liver-storage tests. 2. In the curative-growth assays, on a molar basis the biopotencies of 8'-, 10'- and 12'-apo-beta-carotenal and methyl 8'-apo-beta-carotenoate were 72, 78, 72 and 53% respectively, whereas on a weight basis the corresponding values were 93, 111, 111 and 63%, with respect to beta-carotene taken as 100%. In terms of yield of vitamin A, these values were much lower in the liver-storage tests. 3. When 8'-apo-beta-carotenal was fed, the unchanged aldehyde together with small amounts of the corresponding alcohol and larger proportions of the acid rapidly appeared in the tissues of both rats and chickens. The 8'-apocarotenol, 8'-apocarotenoic acid and its methyl ester were absorbed unchanged. The free acid disappeared most rapidly from the tissues, but its methyl ester persisted in the tissues longest. 4. On the basis of these observations it is suggested that most of an apocarotenal is oxidized to the corresponding acid, which, in turn, is mostly degraded to retinoic acid, with small proportions of it being attacked by the dioxygenase system giving retinal.