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111.
The aim of the paper is to propose two efficient algorithms for the numerical evaluation of Hankel transform of order ν, ν>−1 using Legendre and rationalized Haar (RH) wavelets. The philosophy behind the algorithms is to replace the part xf(x) of the integrand by its wavelet decomposition obtained by using Legendre wavelets for the first algorithm and RH wavelets for the second one, thus representing Fν(y) as a Fourier-Bessel series with coefficients depending strongly on the input function xf(x) in both the cases. Numerical evaluations of test functions with known analytical Hankel transforms illustrate the proposed algorithms. 相似文献
112.
K. Janardhan Reddy J. Rajesh KumarC. Ramachandraiah T. ThriveniA. Varada Reddy 《Food chemistry》2007,101(2):585-591
N-ethyl-3-carbazolecarboxaldehyde-3-thiosemicarbazone (ECCT) is proposed as a new sensitive reagent for the extractive spectrophotometric determination of zinc(II). The ECCT forms yellow colored species of zinc(II) at pH range 3.0–5.5 and the complex was extracted into benzene. The Zn(II)–ECCT complex shows maximum absorbance at 420 nm with molar absorptivity and Sandell’s sensitivity being 1.55 × 104 lit mol−1 cm−1 and 4.212 × 10−3 μg cm−2, respectively. The system obeys Beer’s law in the range of 0.4–6.0 mg/l, with an excellent linearity in terms of correlation coefficient value of 0.999. Most of the common metal ions generally found associated with zinc do not interfere. The repeatability of the method was checked by finding relative standard deviation (RSD). The developed method has been successfully employed for the determination of zinc(II) in foods. Various certified reference materials (NIST 1573, NBS 1572 and NIST SRM 8435) have been tested for the determination of zinc for the purpose of validation of the present method. 相似文献
113.
Effect of water depth on internal heat and mass transfer for active solar distillation 总被引:1,自引:0,他引:1
Rajesh Tripathi 《Desalination》2005,173(2):187-200
In this communication, an attempt has been made to find out the convective heat transfer coefficient for active solar distillation system. It is a well-known fact that the distillate output (the yield) decreases significantly with the increase of water depth in the basin of the solar still. It is also known that more yield is obtained in case of active solar distillation system as compared to passive solar still due to higher temperature difference between the water and inner glass cover temperatures in the active mode. For the present study, experiments have been conducted for 24 hours during winter months for different water depths in the basin (0.05, 0.1 and 0.15 m) for passive as well as active solar distillation system. The objective of the present paper is to study the effect of different water depths in the basin on the heat and mass transfer coefficients. It is inferred that the convective heat transfer coefficient between water and inner condensing cover depends significantly on the water depth in the basin. It is also observed that more yield is obtained during the off shine hours as compared to daytime for higher water depths in solar still (0.10 m and 0.15 m) due to storage effect. 相似文献
114.
This paper examines the reaction pathways and the nature of active sites for CO hydrogenation in general and C2+ oxygenate synthesis over Rh catalysts in particular. 相似文献
115.
Experiments have been carried out with jet mixers to study the solid suspension characteristics. The jet velocities required for solid suspension in 0.5 and 1 m ID tanks were measured experimentally. The nozzle diameter was varied from 0.0156 to 0.05 m. The nozzle clearance from the tank bottom was varied from 0.1 to 0.9 m. Tap water and sand of average sizes 100, 300, and 500 µm were used. The solid loading was varied from 1 to 5% (wt.). The effect of nozzle angle was also studied. A semi‐empirical model has been developed to predict the jet velocity needed to achieve a certain degree of suspension. 相似文献
116.
The effect of immobile water content on contaminant advection and dispersion in unsaturated porous media has been studied using a formulation which assumes that even in the immobile liquid zone, there occurs minor liquid flow. An approach is proposed for computing this liquid velocity. One dimensional numerical simulation is carried out to study the effect of immobile water content on the time of appearance of contaminant at the bottom of an unsaturated column. The numerical model developed is verified using analytical solutions for simple advective-dispersive cases. From the simulations, it was observed that increase in the immobile water content leads to quicker appearance of contaminant. 相似文献
117.
Sajal Ghosh Rajesh Ganesan R. Sridharan T. Gnanasekaran 《Journal of Phase Equilibria and Diffusion》2018,39(6):916-932
The ternary phase diagram of LiCl-KCl-NdCl3 system has been investigated by differential thermal analysis (DTA), followed by characterization of the coexisting phases in the solid state by x-ray diffraction, in order to understand the interactions in the NdCl3-LiCl-KCl ternary system. The results of these experiments showed that LiCl and K2NdCl5 form a non binary join section. This divides the LiCl-KCl-NdCl3 system into two quasi-ternary sections, namely (1) LiCl-KCl-K2NdCl5 and (2) LiCl-K2NdCl5-NdCl3 systems. Both are simple eutectic ternary phase diagrams. The ternary eutectic temperatures and eutectic compositions are determined to be 316?±?3 °C and 53.9 mol.% LiCl-38.7 mol.% KCl-7.4 mol.% K2NdCl5 in the LiCl-KCl-K2NdCl5 quasi-ternary section, while the other eutectic temperature and composition are determined to be 376?±?9 °C and 46.2 mol.% LiCl-32.5 mol.% K2NdCl5-21.3 mol.% NdCl3 in the LiCl-K2NdCl5-NdCl3 quasi-ternary section. A quasi-ternary peritectic reaction is observed at 37.7 mol.% LiCl-36.2 mol.% KCl-26.1 mol.% K2NdCl5 at 445?±?1°C. The primary and secondary crystallization temperatures for the samples are deduced from the heating runs of DTA traces, and the phases responsible for the various thermal events are ascertained. Isothermal sections at chosen temperatures and polythermal liquidus projection with isothermal contours are drawn over the ternary phase field. 相似文献
118.
Daniel Lepek Jose Manuel Valverde Robert Pfeffer Rajesh N. Dave 《American Institute of Chemical Engineers》2010,56(1):54-65
We show experimental results on a proposed technique to enhance the fluidization of nanoparticle beds. This technique consists of the application of an alternating electric field to the nanofluidized bed. Three different field configurations have been tested: co‐flow field, cross‐flow field, and variable field configurations. Nanoparticle agglomerates are naturally charged by contact and tribo charging mechanisms and therefore are agitated by the action of the externally applied field, which enhance fluidization. According to our observations, the best results are obtained for the variable field configuration. In this configuration, the electric field strength is higher at the bottom of the bed, whereas it is almost negligible at the free surface. Thus, the larger agglomerates, which tend to sink at the bottom of the bed due to stratification, and usually impede uniform fluidization, are strongly agitated. It is thought that the strong agitation of the bigger agglomerates that usually sink to the bottom of the bed contributes to further homogenize the distribution of the gas flow within the bed by destabilizing the development of gas channels close to the gas distributor. On the other hand, the smaller agglomerates at the vicinity of the free surface are just weakly excited. Consequently, fluidization is greatly enhanced, whereas at the same time excessive elutriation is avoided. It is demonstrated that this technique is even suitable to achieve highly expanded fluidization of unsieved nanopowder samples even though the fluidization state returns to be heterogeneous upon the electric field being turned off. © 2009 American Institute of Chemical Engineers AIChE J, 2010 相似文献
119.
Rajesh Patel VishnuP. Srivastava Lal DharS. Yadav 《Advanced Synthesis \u0026amp; Catalysis》2010,352(10):1610-1614
The first procedure to access N‐tosylimines directly from alcohols under mild and neutral conditions is reported. The protocol involves saccharin‐lithium bromide‐catalyzed oxidation of alcohols to aldehydes/ketones with chloramine‐T followed by their condensation with the in situ generated oxidation by‐product p‐toluenesulfonamide in the same reaction vessel to afford N‐tosylimines in 40–90% overall yields. The present work opens up a new and efficient synthetic route to N‐tosyimines directly from alcohols in a one‐pot procedure. 相似文献
120.
A method of optimal beamforming for flat Rayleigh faded channels using the Fractional Fourier Transform (FRFT) is considered
in this paper. It has been demonstrated through simulations that optimal beamforming with FRFT allows smaller mean-square
errors in restoring signals degraded with linear time-or frequency variant distortions and Additive White Gaussian Noise.
This is made possible by the additional flexibility that comes with free parameter ‘a’ of the fractional Fourier transform as oppose to the classical Fourier transform (FT). The method is especially useful in
moving source problems, where Doppler Effect produces frequency shift when the source is moving, as in mobile and wireless
communication where user produces the frequency shift while moving. In this paper it is shown through simulations that beamforming
in fractional domain reduces BER as compared to time or frequency domain. 相似文献