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81.
Instantaneous, two-dimensional velocity measurements were conducted in the axial plane of a self-similar turbulent axisymmetric jet. The velocity fields were high-pass filtered to expose the vortical structures. An automated method was used to identify the radial and axial coordinates of the vortex centers and rotational sense, and to measure their size, circulation, vorticity, and energy. New insights into turbulent jets are obtained by plotting statistical distributions for vortex properties as functions of Reynolds number and radial position. While the probability of finding a vortex is uniform up to the edge of the jet, the strongest eddies in the high-pass filtered field occur near the jet axis. The average circulation is directly proportional to the vortex size. The Reynolds number strongly affects the average vorticity, circulation, and energy of the eddies. However, the normalized curves show a good collapse implying that the jet is indeed self-similar. Results for the left and right half-planes of the jet are also presented. Interestingly, we find that contrary to customary drawings of jet flows, a substantial number of both clockwise and counter-clockwise rotating eddies exist on both sides of the jet axis, with almost equal numbers of oppositely rotating vortices close to the jet axis. Further, the disparity in the number of oppositely rotating eddies in each half-plane increases with the eddy size. Nevertheless, these results are consistent with the well-known radial vorticity distribution of axisymmetric jets. 相似文献
82.
Smithia conferta Sm. (Leguminasae), is a commonly used plant in Indian traditional medicine. In the current study anti-ulcer activity of its petroleum ether, alcohol and aqueous extracts of leaves were investigated using different animal models. All extracts were also subjected to phytochemical analysis and their toxic potential. Petroleum ether extract was found to contain steroids; alcohol extract revealed the presence of isoflavonoids, alkaloids and carbohydrates; while aqueous extract was found to contain amino acids, carbohydrates and flavonoids. S. conferta aqueous and alcoholic extracts were found to be non-toxic up to 5000 mg/kg dose level while petroleum ether extract was safe only up to a dose of 2000 mg/kg after single dose administration of the extracts.During confirmation of the claimed anti-ulcer activity, treatment with aqueous and alcoholic extracts showed significant reduction in ulcer index, free acidity as well as total acidity in pylorus ligated rats. However, petroleum ether extract showed relatively less profound reduction in all these indices. The anti-ulcer activity observed in aqueous extract treatment group was nearly equivalent to the standard group. 相似文献
83.
Ramesh Sundar Amalraj Nagarathinam Selvaraj Ganesh Kumar Veluswamy Rahul Pathirickal Ramanujan Raveendran Muthurajan Malathi Palaniyandi Ganesh Kumar Agrawal Randeep Rakwal Rasappa Viswanathan 《Electrophoresis》2010,31(12):1959-1974
Sugarcane is an important commercial crop cultivated for its stalks and sugar is a prized commodity essential in human nutrition. Proteomics of sugarcane is in its infancy, especially when dealing with the stalk tissues, where there is no study to date. A systematic proteome analysis of stalk tissue yet remains to be investigated in sugarcane, wherein the stalk tissue is well known for its rigidity, fibrous nature, and the presence of oxidative enzymes, phenolic compounds and extreme levels of carbohydrates, thus making the protein extraction complicated. Here, we evaluated five different protein extraction methods in sugarcane stalk tissues. These methods are as follows: direct extraction using lysis buffer (LB), TCA/acetone precipitation followed by solubilization in LB, LB containing thiourea (LBT), and LBT containing tris, and phenol extraction. Both quantitative and qualitative protein analyses were performed for each method. 2‐DE analysis of extracted total proteins revealed distinct differences in protein patterns among the methods, which might be due to their physicochemical limitations. Based on the 2‐D gel protein profiles, TCA/acetone precipitation‐LBT and phenol extraction methods showed good results. The phenol method showed a shift in pI values of proteins on 2‐D gel, which was mostly overcome by the use of 2‐D cleanup kit after protein extraction. Among all the methods tested, 2‐D cleanup‐phenol method was found to be the most suitable for producing high number of good‐quality spots and reproducibility. In total, 30 and 12 protein spots commonly present in LB, LBT and phenol methods, and LBT method were selected and subjected to eLD‐IT‐TOF‐MS/MS and nESI‐LC‐MS/MS analyses, respectively, and a reference map has been established for sugarcane stalk tissue proteome. A total of 36 nonredundant proteins were identified. This is a very first basic study on sugarcane stalk proteome analysis and will promote the unexplored areas of sugarcane proteome research. 相似文献
84.
In the present article, the authors have proposed a modified projective adaptive synchronization technique for fractional‐order chaotic systems. The adaptive projective synchronization controller and identification parameters law are developed on the basis of Lyapunov direct stability theory. The proposed method is successfully applied for the projective synchronization between fractional‐order hyperchaotic Lü system as drive system and fractional‐order hyperchaotic Lorenz chaotic system as response system. A comparison between the effects on synchronization time due to the presence of fractional‐order time derivatives for modified projective synchronization method and proposed modified adaptive projective synchronization technique is the key feature of the present article. Numerical simulation results, which are carried out using Adams–Boshforth–Moulton method show that the proposed technique is effective, convenient and also faster for projective synchronization of fractional‐order nonlinear dynamical systems. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
85.
In this paper, we explore how firms can manage their raw material sourcing better by developing appropriate sourcing relationships with their raw material suppliers. We detail three empirical case studies of firms explaining their different raw material sourcing strategies: (a) firms can adopt a hands-off approach to raw material management, (b) firms can supply raw material directly to their suppliers, and this may be beneficial for some agents in the supply chain, and (c) firms can bring their component suppliers together, and the resulting cooperation between suppliers can be beneficial for supply chain. We then analytically model the three raw material scenarios encountered in our empirical work, examine the resulting profits along the supply chain, and extend the results to a competitive buyer scenario. Overall, our results show that active management of raw material sourcing can add value to supply chains. 相似文献
86.
Himanshu Joshi Arpit Agarwal Bhalchandra Puranik Chang Shu Amit Agrawal 《国际流体数值方法杂志》2010,62(4):403-427
The lattice Boltzmann method (LBM) has established itself as an alternative approach to solve the fluid flow equations. In this work we combine LBM with the conventional finite volume method (FVM), and propose a non‐iterative hybrid method for the simulation of compressible flows. LBM is used to calculate the inter‐cell face fluxes and FVM is used to calculate the node parameters. The hybrid method is benchmarked for several one‐dimensional and two‐dimensional test cases. The results obtained by the hybrid method show a steeper and more accurate shock profile as compared with the results obtained by the widely used Godunov scheme or by a representative flux vector splitting scheme. Additional features of the proposed scheme are that it can be implemented on a non‐uniform grid, study of multi‐fluid problems is possible, and it is easily extendable to multi‐dimensions. These features have been demonstrated in this work. The proposed method is therefore robust and can possibly be applied to a variety of compressible flow situations. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
87.
Vijay K. Agrawal Shahnaz Bano Keshav C. Mathur Padmakar V. Khadikar 《Journal of Chemical Sciences》2000,112(2):137-146
The paper gives a brief account of the recently introduced Szeged index (Sz). Using this index antitubercular activities of
N-2,4-difluorophenyl quinolones are subjected to quantitative structure-activity relationship analysis. The potential of Sz
related to the Wiener index (W) is critically discussed. In addition, Huckel molecular orbital energies:E
HOMO,E
LUMO andE
total were also used for comparing and modelling antitubercular activities of the quinolones. The results, based on univariate
as well as multivariate regressions, have shown that W, SZ andE
total give better results and that the correlations improve in multivariate regression analyses. 相似文献
88.
It is emphasized that any equation of state (EOS) based on the generalized Lennard-Jones potential or the Mie potential, suffers
from two main shortcomings as pointed out by Stacey and Davis [2]. One of the shortcomings viz. the problem related to imaginary numbers for the exponents in the potential function, has been removed recently by Jiuxun
[11] by using a relationship between the exponents. However, the modified EOS obtained by Jiuxun suffers from the second shortcoming
viz. it gives lower values for −B
0
B″0, an important equation of state parameter related to the second pressure derivative of the bulk modulus. Values of B
0
B″0 obtained by Jiuxun are not consistent with those reported by Stacey and Davis.
相似文献
89.
Prof. O. P. Agrawal Prof. M. M. Stanišić Prof. S. Saigal 《Archive of Applied Mechanics (Ingenieur Archiv)》1988,58(1):9-14
Summary The problem considered is that of heavy masses moving on lightweight rectangular plates of orthotropic materials, slated for use in space structures. The dynamic equation of motion for orthotropic plates which contains singularities in both space and time variables is first presented. The response is expressed as a summation of double series of eigenfunctions. The equation of motion is transformed into an integro-differential equation for modal amplitudes using the Green's function. The Green's function is chosen to satisfy the initial conditions, the boundary conditions, and the transient conditions due to the moving masses. The solution series exhibits a good convergence. The effect of orthotropicity on natural frequencies and dynamic responses is demonstrated.
Dynamische Antwort orthotroper Platten auf bewegte Massenpunkte
übersicht Behandelt wird die Bewegung von Massenpunkten auf rechteckigen Leichtbau-Platten aus orthotropem Werkstoff, die für Raumfahrtkonstruktionen vorgesehen sind. ZunÄchst wird die Bewegungsgleichung orthotroper Platten mit singulÄren Ausdrücken in den Raum- und Zeitkoordinaten angegeben. Die Antwort wird als Doppelsumme einer zweifachen Reihenentwicklung dargestellt und die Bewegungsgleichung mit Hilfe der Greenschen Funktion in eine Integro-Differentialgleichung für die Modalamplituden transformiert. Die Greensche Funktion ist so gewÄhlt, da\ sie die Anfangs- und Randbedingungen sowie die übergangsbedingungen unter der bewegten Masse erfüllt. Die Lösung durch Reihenentwicklung zeigt gute Konvergenz. Der Einflu\ der Orthotropie auf die Eigenfrequenzen und die dynamischen Antworten wird veranschaulicht.相似文献
90.
Ruchi Ruchi Nurhayat Ispir P. N. Agrawal 《Mathematical Methods in the Applied Sciences》2017,40(16):5687-5706
Ren and Zeng (2013) introduced a new kind of q‐Bernstein–Schurer operators and studied some approximation properties. Acu et al. (2016) defined the Durrmeyer modification of these operators and studied the rate of convergence and statistical approximation. The purpose of this paper is to introduce a Kantorovich modification of these operators by using q‐Riemann integral and investigate the rate of convergence by means of the Lipschitz class and the Peetre's K‐functional. Next, we introduce the bivariate case of q‐Bernstein–Schurer–Kantorovich operators and study the degree of approximation with the aid of the partial modulus continuity, Lipschitz space, and the Peetre's K‐functional. Finally, we define the generalized Boolean sum operators of the q‐Bernstein–Schurer–Kantorovich type and investigate the approximation of the Bögel continuous and Bögel differentiable functions by using the mixed modulus of smoothness. Furthermore, we illustrate the convergence of the operators considered in the paper for the univariate case and the associated generalized Boolean sum operators to certain functions by means of graphics using Maple algorithms. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献