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71.
In recent years, an increasing number of data-intensive applications deal with continuously changing data objects (CCDOs), such as data streams from sensors and tracking devices. In these applications, the underlying data management system must support new types of spatiotemporal queries that refer to the spatiotemporal trajectories of the CCDOs. In contrast to traditional data objects, CCDOs have continuously changing attributes. Therefore, the spatiotemporal relation between any two CCDOs can change over time. This problem can be more complicated, since the CCDO trajectories are associated with a degree of uncertainty at every point in time. This is due to the fact that databases can only be discretely updated. The paper formally presents a comprehensive framework for managing CCDOs with insights into the spatiotemporal uncertainty problem and presents an original parallel-processing solution for efficiently managing the uncertainty using the map-reduce platform of cloud computing. 相似文献
72.
Chandrasekar Saravanan Srinivasan Palaniappan Valaboju Akhila Sunkara Sakunthala Madhavendra Prakriti Ranjan Bangal 《应用聚合物科学杂志》2011,120(4):2421-2427
Sulfonated‐p‐cresol (SPC) was used as novel dopant for the first time in the synthesis of polyaniline in 3D nanofiber networks (PANI‐3D). Polyaniline in 3D nanofiber network was prepared using organic solvent soluble benzoyl peroxide as oxidizing agent in presence of SPC and sodium lauryl sulfate (SLS) surfactant via inverted emulsion polymerization pathway. The influence of synthesis conditions such as the concentration of the reactants, stirring/static condition, and temperature etc., on the properties and formation of polyaniline nanofiber network were investigated. Polyaniline in 3D nanofiber network with 40–160 nm (diameter), high yield (134 wt % with respect to aniline used), and reasonably good conductivity (0.1 S/cm) was obtained in 24 h time. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
73.
Santanu Bandyopadhyay Ranjan K. Malik Uday V. Shenoy 《Computers & Chemical Engineering》1998,22(12):4838-1744
The temperature–enthalpy (T–H) diagram of a distillation column at practical near-minimum thermodynamic condition (PNMTC) or the column grand composite curve (CGCC) is a useful representation for energy targeting studies and may be generated from a converged simulation of a base-case column design. The calculation procedure for the CGCC involves determination of the net enthalpy deficit at each stage by generating envelopes from either the condenser end (top-down approach) or the reboiler end (bottom-up approach). However, the values calculated by the two approaches differ for stages with feeds because existing procedures for CGCC generation do not consider the enthalpy balances at the feed stages. In fact, the net enthalpy deficits at feed stages calculated by both approaches are erroneous even for the simplest case of binary distillation. A feed stage correction (FSC) that rigorously considers the mass and enthalpy balance equations at feed stages is proposed in this work to resolve the discrepancy. Instead of assuming that the compositions obtained from the converged simulation for a feed stage will remain unchanged at PNMTC, the pinched compositions for the feed are determined by the intersection of the equilibrium curve and the feed q-line. Rather than perform an additional flash calculation to establish the pinched feed compositions, a quadratic approximation is developed here for column targeting purposes by assuming the relative volatility obtained from the simulation to remain constant in the neighborhood of the feed stage. The proposed FSC ensures that the CGCC is identical whether the calculations are performed by the top-down approach or the bottom-up approach. The effect of the FSC on the targets for energy conservation by reflux modification, feed conditioning, and introduction of side reboilers/condensers is discussed. As the energy target for reflux modification is determined by the CGCC pinch which typically occurs at or close to the feed location, the significance of the FSC on the reflux modification target is highlighted through several case studies including a complex column featuring multiple feeds and consequently multiple pinch points. The CGCCs for these case studies are generated by a computer program based on the FSC and a single analytical equation for the calculation of the net enthalpy deficits that allows every stage to have a feed, liquid product, vapor product, and side exchanger. The studies show that the reflux modification targets may be erroneous in many cases, if the FSC is ignored. 相似文献
74.
A novel electrical-mobility-based technique to measure total particle number concentration over a selected size range is presented. Charged particles are condensed out onto an electrode that is shaped such that the product of its transfer function and the particle charging efficiency is a constant, independent of particle size. The resulting total current is then proportional to the number concentration of the sampled particles over the collected size range. The theoretical approach for the calculation of the electrode shape function is described. The extension of this technique for measurement of higher moments of the particle size distributions over a desired size range is briefly discussed.This concept is used to design a new instrument, called the tailored electrode concentration sensor (TECS). For validation of the theoretical concept, the collection electrode in the TECS instrument is designed for concentration measurements over a size range of 30–90 nm. In the TECS, the collection section is located downstream of an electrostatic precipitator section, where the sampled flow is split into aerosol and sheath flows, similar to the design of the MEAS [Ranjan, M., & Dhaniyala, S., (2007), Theory and design of a new miniature electrical-mobility aerosol spectrometer, Journal of Aerosol Science, 38(9), 950–963]. This results in a compact, low pressure drop instrument. Experimental results confirm that the response of the optimally-shaped electrode in the TECS system is only proportional to total number concentration over the selected size range. 相似文献
75.
Anil Kumar Mandeep Kaur Rajeev Kumar Pinaki Ranjan Sengupta Vasantha Raman Gopal Bhatia Kedar Nath Sood 《Journal of Materials Science》2010,45(5):1393-1400
Carbon–copper composites with varying copper to carbon ratio of 0.66–1.5 (by weight) were developed from coal-tar-pitch-derived
green coke (as such or modified with natural graphite) as carbon source and electrolytic grade copper powder at different
heat treatment temperatures (HTTs) of 1000–1400 °C. The physical, mechanical, and electrical properties differ depending upon
the HTT and also on copper to carbon ratio (Cu/C). The composites prepared at HTT of 1100 °C having Cu/C ratio of 0.66 and
0.9 exhibited a high bending strength of 150 and 140 MPa, bulk density of 2.63 and 2.81 gm/cm3, electrical resistivity of 1.6 and 0.96 m Ω cm and shore hardness of 88 and 84, respectively, in spite of well-known inadequate
wettability between copper and carbon. Increasing the temperature from 1100 °C for processing of the composites deteriorated
the properties mainly due to the loss of copper through melting above 1100 °C as revealed by X-ray, scanning electron microscopy,
thermal analysis and EDAX studies. 相似文献
76.
Futamura N. Aluru S. Ranjan D. Hariharan B. 《Parallel and Distributed Systems, IEEE Transactions on》2002,13(6):544-555
We present faster sequential and parallel algorithms for computing the solvent accessible surface area (ASA) of protein molecules. The ASA is computed by finding the exposed surface areas of the spheres obtained by increasing the van der Waals radii of the atoms with the van der Waals radius of the solvent. Using domain specific knowledge, we show that the number of sphere intersections is only O(n), where n is the number of atoms in the protein molecule. For computing sphere intersections, we present hash-based algorithms that run in O(n) expected sequential time and O(n/p) expected parallel time and sort-based algorithms that run in worst-case O(n log n) sequential time and O(n log n/p) parallel time. These are significant improvements over previously known algorithms which take O(n2) time sequentially and O(n2/p) time in parallel. We present a Monte Carlo algorithm for computing the solvent accessible surface area. The basic idea is to generate points uniformly at random on the surface of spheres obtained by increasing the van der Waals radii of the atoms with the van der Waals radius of the solvent molecule and to test the points for accessibility. We also provide error bounds as a function of the sample size. Experimental verification of the algorithms is carried out using an IBM SP-2 相似文献
77.
Jatin R. Thakkar Ravji D. Patel Ranjan G. Patel Vithal S. Patel 《Polymer International》1990,22(2):143-146
Glass fibre reinforced epoxy composites were fabricated from the matrix resins diglycidyl ether of bisphenol A (DGEBA) and triglycidyl-p-aminophenol (TGAP) using diethylene triamine as curing agent. The epoxy laminates were evaluated for their mechanical properties, dielectrical properties and chemical resistance. Significant improvement in fiexural strength but a slight deterioration in dielectrical properties were observed on incorporation of an epoxy fortifier into the resin system before fabricating the composites. 相似文献
78.
A numerical study of pulsatile blood flow in an eccentric catheterized artery using a fast algorithm
The pulsatile blood flow in an eccentric catheterized artery is studied numerically by making use of an extended version of the fast algorithm of Borges and Daripa [J. Comp. Phys., 2001]. The mathematical model involves the usual assumptions that the arterial segment is straight, the arterial wall is rigid and impermeable, blood is an incompressible Newtonian fluid, and the flow is fully developed. The flow rate (flux) is considered as a periodic function of time (prescribed). The axial pressure gradient and velocity distribution in the eccentric catheterized artery are obtained as solutions of the problem. Through the computed results on axial pressure gradient, the increases in mean pressure gradient and frictional resistance in the artery due to catheterization are estimated. These estimates can be used to correct the error involved in the measured pressure gradients using catheters. 相似文献
79.
Andrew Gdowski Amalendu Ranjan Anindita Mukerjee Jamboor Vishwanatha 《International journal of molecular sciences》2015,16(2):3990-3995
Treatments utilizing monoclonal antibody therapeutics against intracellular protein-protein interactions in cancer cells have been hampered by several factors, including poor intracellular uptake and rapid lysosomal degradation. Our current work examines the feasibility of encapsulating monoclonal antibodies within poly(lactic-co-glycolic acid) (PLGA) nanoparticles using a water/oil/water double emulsion solvent evaporation technique. This method can be used to prepare protective polymeric nanoparticles for transporting functional antibodies to the cytoplasmic compartment of cancer cells. Nanoparticles were formulated and then characterized using a number of physical and biological parameters. The average nanoparticle size ranged from 221 to 252 nm with a low polydispersity index. Encapsulation efficiency of 16%–22% and antibody loading of 0.3%–1.12% were observed. The antibody molecules were released from the nanoparticles in a sustained manner and upon release maintained functionality. Our studies achieved successful formulation of antibody loaded polymeric nanoparticles, thus indicating that a PLGA-based antibody nanoformulation is a promising intracellular delivery vehicle for a large number of new intracellular antibody targets in cancer cells. 相似文献
80.
Kumud Ranjan Jha Manish Rai 《AEUE-International Journal of Electronics and Communications》2010,64(2):177-185
This paper presents a new slow wave open-loop resonator filters with reduced size and improved stopband characteristics. A comprehensive treatment of different kind of coupling in this structure is demonstrated. Two and four resonator band pass filters at center frequency 2.15 and 2.30 GHz with different bandwidth are designed. The simulated results are verified with the help of two different software packages (IE3D and Sonnet Lite). 相似文献