Finite element analysis of transonic flows in cascades: Importance of computational grids in improving accuracy and convergence

The finite element method is applied for the solution of transonic potential flows through a cascade of airfoils. Convergence characteristics of the solution scheme are discussed. Accuracy of the numerical solutions is investigated for various flow regions in the transonic flow configuration. The design of an efficient finite element computational grid is discussed for improving accuracy and convergence

Effect of zinc fertilizer applications on yield and element contents of some registered chickpeas varieties

In this study, the effect of zinc fertilizer applications on different chickpea varieties and the most suitable zinc application dose were investigated under the field conditions in May to September of 2003 and 2004. Three types of chickpeas (Cicer arietinum cv.Canitez-87, cv. ILC-482 and cv. Gokce) were studied under irrigated conditions. Zinc was applied to the soil at four doses 0, 0.5, 1.0 and 1.5 kg da-1 before sowing. During the experiment, leaf samples were regularly collected every week to determine the chlorophyll content of fresh leaf tissue. The changes in the total chlorophyll content were followed. Chickpea samples of each variety were harvested mainly taking into account maturation periods. Leaf chlorophyll concentration, grain phytic acid, zinc, nitrogen and phosphorus contents were determined in chickpea varieties. According to the results of the statistical analysis, the chlorophyll content in the leaves showed a significant difference among the varieties for both years (P < 0.01).The values of P, phytic acid and Zn contents in the seed and the Zn content in the leaf of ILC-482 variety were found to be higher when compared with other varieties. According to correlation test results, there were significant (P < 0.05) differences among the described criteria. Significant correlations were observed between phosphorus content in seed and grain yield (r= 0.75*); total chlorophyll content of leaves and grain yield (r= 0.78*); total chlorophyll content of leaves and phytic acid (r= 0.93**); total chlorophyll content of leaves and phosphorus content in seed (r= 0.72*) particularly in ILC -482 variety. The application of zinc fertilizer did not provide a significant increase in the yield. However, significant increases were observed in phosphorus, phytic acid and zinc content in the seed and the chlorophyll concentration in the leaf through zinc fertilizer application at a dose of 1.0 kg da-1 (P < 0.01).Key words: Cicer arietinum L., chlorophyll concentration, phytic acid, zinc, nitrogen, phosphorus

Effect of zinc fertilizer applications on yield and element contents of some registered chickpeas varieties

In this study, the effect of zinc fertilizer applications on different chickpea varieties and the most suitable zinc application dose were investigated under the field conditions in May to September of 2003 and 2004. Three types of chickpeas (Cicer arietinum cv.Canitez-87, cv. ILC-482 and cv. Gokce) were studied under irrigated conditions. Zinc was applied to the soil at four doses 0, 0.5, 1.0 and 1.5 kg da-1 before sowing. During the experiment, leaf samples were regularly collected every week to determine the chlorophyll content of fresh leaf tissue. The changes in the total chlorophyll content were followed. Chickpea samples of each variety were harvested mainly taking into account maturation periods. Leaf chlorophyll concentration, grain phytic acid, zinc, nitrogen and phosphorus contents were determined in chickpea varieties. According to the results of the statistical analysis, the chlorophyll content in the leaves showed a significant difference among the varieties for both years (P < 0.01).The values of P, phytic acid and Zn contents in the seed and the Zn content in the leaf of ILC-482 variety were found to be higher when compared with other varieties. According to correlation test results, there were significant (P < 0.05) differences among the described criteria. Significant correlations were observed between phosphorus content in seed and grain yield (r= 0.75*); total chlorophyll content of leaves and grain yield (r= 0.78*); total chlorophyll content of leaves and phytic acid (r= 0.93**); total chlorophyll content of leaves and phosphorus content in seed (r= 0.72*) particularly in ILC -482 variety. The application of zinc fertilizer did not provide a significant increase in the yield. However, significant increases were observed in phosphorus, phytic acid and zinc content in the seed and the chlorophyll concentration in the leaf through zinc fertilizer application at a dose of 1.0 kg da-1 (P < 0.01).Key words: Cicer arietinum L., chlorophyll concentration, phytic acid, zinc, nitrogen, phosphorus

Dissipation in a finite-size bath

Cataloged from PDF version of article.We investigate the interaction of a particle with a finite-size bath represented by a set of independent linear oscillators with frequencies that fall within a finite bandwidth. We discover that when the oscillators have particular frequency distributions, the finite-size bath behaves much as an infinite-size bath exhibiting dissipation properties and thus allowing irreversible energy absorption from a particle immersed in it. We also present a reinterpretation of the Langevin equation using a perturbation approach in which the small parameter represents the inverse of the number of oscillators in the bath, elucidating the relationship between finite-size and infinite-size bath responses

Trapping of vibration energy into a set of resonators: Theory and application to aerospace structures

Cataloged from PDF version of article.This paper presents the theory of a novel mechanism of energy absorption and induced damping in structural systems and its application to aerospace industry. The underlying principles of the physical phenomena have been addressed in several earlier publications, which focused on prototypical systems of absorbers that consist of a set of single-degree-of-freedom resonators. This paper generalizes those theoretical developments to the case of a cluster of beams attached to a continuous primary structure, to develop predictive methods for the expected performance of this new type of absorber, with particular emphasis on its optimal design. An embodiment of the conceived device is illustrated for an aerospace structure, a satellite, with the purpose of reducing the vibration of the electronic components on board during lift-off. Experimental results illustrate the feasibility and the attractiveness of this new absorption technique. (C) 2011 Elsevier Ltd. All rights reserved

Frequency intermittency and energy pumping by linear attachments

Cataloged from PDF version of article.The present paper considers the problem of realizing an effective targeted energy pumping from a linear oscillator to a set of ungrounded linear resonators attached to it. Theoretical as well as numerical results demonstrate the efficacy of using a complex attachment as a passive absorber of broadband energy injected into the primary structure. The paper unveils also the existence of an instantaneous frequency associated with the master response characterized by intermittency: a rather surprising result for a linear autonomous system. Comparison with nonlinear energy sinks demonstrates that the two systems have some analogies in this respect and that the linear complex attachment is a very efficient energy trap. (C) 2014 Elsevier Ltd. All rights reserved