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81.
The understanding of the flow characteristics and effect of gas-solid interactions in pneumatic risers is fundamental to investigate to ensure effective design cost-effective operation. Thus, to understand the effect of gas-solid interactions on the hydrodynamics of newly proposed conversing risers, this study mainly focused on predicting pressure drop in the dilute phase pneumatic conveying system. The experiments were conducted in a converging riser having a convergence angle of 0.2693°. Various solid particles such as sago, black mustard, and alumina have been considered to study the effect of particle sizes and density on the pressure drop. The experimental outcomes indicate that the total pressure drop increases with an increase in the solid density and gas mass flow rate. Moreover, smaller particle sizes are also increased the pressure drop. An empirical correlation is developed for the prediction of total pressure drop ΔPT in converging pneumatic riser via dimensional analysis. All dependent variables such as particle and air density, drag force, acceleration due to gravity, the mass flow rate of air and particle, the diameter of particle and converging riser, the height of converging riser were considered to develop the empirical correlation. The established relationship is tested, and experimental data have been fitted for its validation. The estimated relative error of less than 0.05 proved the significance of the developed correlation. Hence, it can be stated that the established relationship is useful in studying the effects of various parameters on the pressure drop across the length of the conversing riser. 相似文献
82.
A number of studies have modeled flow and mixing of granular materials using the discrete element method (DEM). In an attempt to reduce computational costs, many of these DEM studies model particles larger than the actual particle size without investigating the implications of this assumption. Using DEM, the influence of the modeled particle size on flow and mixing in a bladed granular mixer is studied. The predicted flow microdynamics, including mixing rates, are strongly dependent on the particle diameter. The effect of particle size on macroscopic advective flow also is significant, particularly for dilute flow regions. These results suggest that the influence of particle size needs to be taken into consideration when using larger particles in DEM mixing simulations. To guide scale‐up efforts, particle‐size‐based scaling relationships for several key flow measurements are presented. © 2014 American Institute of Chemical Engineers AIChE J, 61: 46–57, 2015 相似文献
83.
This paper describes a PC based centralized monitoring of the running condition of a multi-machine system. This kind of monitoring from remote central location is one of the primary requirements in today’s era of automation. The convergence of embedded system like microcontroller/DSP/FPGA, etc., now-a-days, is adding a new dimension to enhance the capability of the PC based data acquisition. In this present approach, conditions of different parameters of each motor have been measured by dedicated microcontroller based hardware. All these units are connected in a network using bus topology. All parameters are communicated to a remote PC through this bus where user friendly state-of-the-art developed software stores it for display and analysis purposes. 相似文献
84.
Yogesh S. Kashyap Ashish Agrawal P.S. Sarkar Mayank Shukla Tushar Roy Amar Sinha 《NDT & E International》2011,44(1):41-46
We have used the contrast transfer function based X-ray phase retrieval technique for phase retrieval studies on a two-component system. Pyro-carbon coated alumina matrix was chosen as a two-component system for these studies. Simulations as well as experimental results are presented. This paper shows that X-ray phase contrast along with phase retrieval can become an alternative tool for non-destructive characterization of these materials. We have also attempted to retrieve the spatial distribution of the projected thickness map of the two different elements. 相似文献
85.
Krishanu Sarkar Mahasweta Nandi Manirul Islam M. Mubarak Asim Bhaumik 《Applied Catalysis A: General》2009,352(1-2):81-86
Phenyl functionalized 2D-hexagonal mesoporous silica material has been synthesized by cationic/non-ionic mixed surfactant templating route. The phenyl group of this mesoporous material is further functionalized via nitration and then reduction of that nitro group to amino functionality, followed by Schiff base condensation and heterogenization of a palladium(II) complex, yielded an ortho-metalated palladium(II) complex anchored in a ordered mesoporous silica matrix. This supported metal complex acts as an efficient catalyst in the Suzuki cross-coupling reaction and shows high selectivity for the bi-aryl products. 相似文献
86.
This paper considers the problem of finding the least cost rectilinear distance path in the presence of convex polygonal congested regions. We demonstrate that there are a finite, though exponential number of potential staircase least cost paths between a specified pair of origin–destination points. An upper bound for the number of entry/exit points of a rectilinear path between two points specified a priori in the presence of a congested region is obtained. Based on this key finding, a “memory-based probing algorithm” is proposed for the problem and computational experience for various problem instances is reported. A special case where polynomial time solutions can be obtained has also been outlined. 相似文献
87.
We report the preparation of ordered polyaniline nanorod arrays by a simple method without the use of any template. The synthesis method is by a chemical route, viz. dispersion polymerization of aniline in polyvinyl alcohol. The nanorods obtained have a diameter of 100-500 nm and a length of a few micrometers. Films containing the nanorod assembly have been characterized by SEM, XRD and FTIR spectroscopy. We have also measured I-V characteristics and the temperature dependence of the conductivity of the films. We discuss the formation mechanism of the self-assembled nanostructures, the morphology of the films, and the crystallinity and the transport mechanism. 相似文献
88.
Kumar Nikhil Verma A. K. Sardana Sahil Sarkar K. Singh T. N. 《Bulletin of Engineering Geology and the Environment》2018,77(2):595-608
Bulletin of Engineering Geology and the Environment - Landslides that occur due to the rapid motion of a rock-mass are a primary risk in mountainous terrains and are a danger to human life and... 相似文献
89.
The results of an experimental investigation on scour of noncohesive sediment beds (uniform and nonuniform sediments) downstream of an apron due to a submerged horizontal jet issuing from a sluice opening are presented. Attempts are made to explain the similarity existing in the scour process and profiles (including dune in the downstream of the scour hole). The scour profiles at different times follow a particular geometrical similarity and can be expressed by the combination of two polynomials. Using experimental scour depth at different times, the time variation of scour depth is scaled by an exponential law, where time scale increases linearly with densimetric Froude number. The equilibrium scour depth, related to the sediment size relative to the sluice opening, decreases with increase in sediment size and sluice opening. On the other hand, the equilibrium scour depth increases with increase in densimetric Froude number. The variation of equilibrium scour depth with tailwater depth indicates a critical tailwater depth corresponding to a minimum equilibrium scour depth. The effect of sediment gradation on scour depth is pronounced for nonuniform sediments, which reduce scour depth significantly due to formation of an armor layer, and therefore prompted study of the reduction of scour depth by a launching apron placed downstream of the rigid apron. The results show that the average reduction of scour depth by placing a launching apron was 39%, having a maximum of 57.3% and a minimum of 16.2%. The characteristic parameters affecting maximum equilibrium scour depth are identified based on the physical reasoning and dimensional analysis. Equation of maximum equilibrium scour depth obtained empirically agrees well with the experimental data. 相似文献
90.
A simple and novel interferometric setup for wave-front testing that uses a cross slit is described. In this method, the test beam illuminates a cross slit placed at the front focal plane of a Fourier lens. It selects two orthogonal slices from the test beam, and the interference of these two beams is observed at a slightly defocused plane near the back focal plane. Fringes of different conical forms (circular, elliptical, or hyperbolic) so obtained can be used for testing a coherent wave front in general. The theory, supported by some experimental results, is presented. An application of the method to the study of the nature of asymmetry in the beam profile of a semiconductor diode laser beam is demonstrated. 相似文献