Effect of fasting condition on multi-substrate carbon oxidation and nitrification system in an upflow packed-bed biofilm reactor

The performance of an upflow packed-bed biofilm reactor has been analyzed under multisubstrate limitation by considering simultaneous carbon oxidation and nitrification reactions. The fasting shock load of inlet methanol concentration has a much more pronounced effect on the response of the system compared to that of inlet NH₄⁺ -nitrogen concentration. The exit concentration of NH₄⁺ -nitrogen drops very close to zero, thereby showing essentially complete nitrification during methanol fasting condition. Further, the concentration profiles of oxygen within the biofilm show significant variation during methanol fasting and nonfasting conditions whereas during NH₄⁺ -nitrogen fasting conditions the oxygen concentration profile in the biofilm remains essentially unaffected.     

GPU-accelerated registration of hyperspectral images using KAZE features

The Journal of Supercomputing - Image registration is a common task in remote sensing, consisting in aligning different images of the same scene. In the particular case of hyperspectral images, the...     

Efficient routing for IP subnet VLAN over Ethernet

Existing IP routing algorithms have been developed mainly for non‐VLAN networks. For these routing algorithms to work, an end station must be attached to its associated network. The introduction of VLAN has, however, allowed the physical location of the end station to be changed from time to time. Therefore, some extra mechanism is required to support routing in VLAN environment. Existing approaches have some drawbacks in terms of inefficiency in traffic forwarding and switch software complexity. In this paper, a simple and efficient method for routing over IP subnet VLAN in Ethernet is proposed. This method has been implemented in hardware and found to work correctly. Various measurements and analyses have been performed to verify the efficiency of this protocol. Copyright © 2002 John Wiley & Sons, Ltd.     

Hydrocarbon Group Analysis of Arabian Crude Oils TBP-Fractions

Experimental studies have been carried out on hydrocarbon group analysis of commercial Arabian crude oil fractions corresponding to the true boiling point ranges or 200-400 ast;F, 400-500 *F 500-650 *F, 650-850 *F, and 850 *F-K The crude oils included Arab heavy (API* = 28·0), Arab medium (API* = 30·0), Arab light (API* = 33·3), and Arab Berry extra light (API* = 36*9). Waters Hydrocabon Group Analyzer (HGA) system interfaced with model 730 Data Module has been used to obtain the compositional analysis in terms of saturates, neutral aromatics, polar aromatics and asphaltcnes.     

Generalized Filter Topology Using Grounded Components and Single Novel Active Element

This paper introduces a new active element combining the useful features of differential voltage, dual-X and first generation current conveyors. The new proposed active element is further utilized to introduce a new generalized filter topology employing grounded components only. The proposed single active element-based topology benefits from first-order and second-order filter realization by appropriate impedance specialization. The circuit topology with single current input provides two output currents and voltages in each case. A thorough study of proposed active element along with extensive simulations is carried out to validate the filter topology. A detailed non-ideal study is also given. To further support the usefulness of filter topology, higher-order filters are also realized. The new active element and the new filter structure provide advancement to the existing knowledge; with the scope of active element being further exploited for analog signal processing applications in general. The proposed differential voltage dual-X first generation current conveyor (DV-DXCCI) and its filtering applications are simulated using TSMC 0.25  \(\upmu \) m technology.     

Computation of entropy generation in dissipative transient natural convective viscoelastic flow

Entropy generation is an important aspect of modern thermal polymer processing optimization. Many polymers exhibit strongly non‐Newtonian effects and dissipation effects in thermal processing. Motivated by these aspects in this study, a numerical analysis of the entropy generation with viscous dissipation effect in an unsteady flow of viscoelastic fluid from a vertical cylinder is presented. The Reiner‐Rivlin physical model of grade 2 (second‐grade fluid) is used, which can envisage normal stress variations in polymeric flow‐fields. Viscosity variation is included. The obtained governing equations are resolved using implicit finite difference method of Crank‐Nicolson type with well imposed initial and boundary conditions. Key control parameters are the second‐grade viscoelastic fluid parameter (), viscosity variation parameter (), and viscous dissipation parameter (). Also, group parameter (), Grashof number (Gr), and Prandtl number (Pr) are examined. Numerical solutions are presented for steady‐state flow variables, temperature, time histories of friction, wall heat transfer rate, entropy, and Bejan curves for distinct values of control parameters. The results specify that entropy generation decreases with augmenting values of , , and Gr. The converse trend is noticed with increasing Pr and . Furthermore, the computations reveal that entropy and Bejan lines only occur close to the hot cylinder wall.     

Dual substrate limitations in upflow packed-bed biofilm reactors — a theoretical study

The performance of an upflow packed-bed biofilm reactor has been analyzed under dual substrate limitation conditions. The numerical solution of the proposed equations defining the system has been obtained for a wide range of operating conditions for a case of practical significance involving glucose and oxygen as dual substrates. The results show that the inlet glucose concentration defines the limiting substrate at a position near the inlet of the reactor. For inlet glucose concentrations up to 300 mg/l, glucose acts as the limiting substrate. However, for inlet concentrations of 400 mg/l of glucose or higher, oxygen assumes the role of the limiting substrate at that position. For all other positions in the reactor, glucose acts as the limiting substrate, irrespective of its inlet concentration. Extensive computations were performed in order to define regions where glucose, oxygen or both are limiting. The predicted results have been found to be in agreement with the theoretical criteria, proposed in the literature, of determining the limiting substrate.     

Membrane concentration potentials across heavy metal soap membranes

The alumina mixed copper soap pellets of different fatty acids (C₆−C₁₆) have been prepared. The pellets are used as membranes of electropositive character. The concentration potential studies have been carried out with potassium chloride solutions. Transport number of counterions and selective ionic permeability through these membranes have been calculated. The values of both these parameters increase with increase in the number of C-atoms of the hydrocarbon chain of copper soaps. This seems to be due to lowering in solubility and increase in crosslinking in the membrane material.