Removal of Diazinon from aqueous solution by electrocoagulation process using aluminum electrodes

Electrocoagulation (EC) is an electrochemical method to treat polluted wastewaters and aqueous solutions. In this paper, the removal of Diazinon was studied by EC on aluminum electrode. The effect of several parameters such as initial concentration of Diazinon, current density, solution conductivity, effect of pH, and electrolysis time were investigated on EC performance. The obtained results showed that the removal efficiency of EC depends on the current density, initial concentration of Diazinon and electrolysis time. The optimum pH is 3 and also the solution conductivity has no significant effect on removal efficiency.     

High output impedance current-mode lowpass,bandpass and highpass filters using current controlled conveyors

Three new current-mode second-order filter configurations which employ one or two current controlled conveyors (CCCIIs) and three passive elements are presented. Each proposed filter can realize one of the bandpass, lowpass or highpass responses all at high impedance outputs. The proposed filters offer current-control of pole angular frequency ω_o without disturbing the parameter ω_o /Q. No component matching is required and all the passive and active sensitivities are low. PSPICE simulation results are given to confirm the theoretical analysis.     

Solid-phase extraction for simultaneous separation and preconcentration of Fe(III) and Zn(II) traces using three chelatants and Ramelak bark-derived activated carbon as a new bio-sorbent

This article introduces a comparative study for the simultaneous separation and preconcentration of Fe(III) and Zn(II) traces in various water samples using three well-known ligands as chelating agents and activated carbon (AC) derived from Ramelak bark as a new bio-sorbent prior to the determination by ?ame atomic absorption spectrometry. The chelating agents were 4,4’-[(4-Cyano-phenyl)methylene]bis(3-methyl-1-phenyl-1H-pyrazol-5-ol) (CMBM), diethyldithiocarbamate (DDTC) and ammonium pyrrolidine dithiocarbamate (APDC). CMBM was synthesized by a procedure reported in the literature. The newly prepared AC was characterized by Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared (FTIR) Spectrometry. The analytical parameters affecting the separation efficiency of the analytes including pH, shaking time, chelating agent volume (concentration), sorbent mass, sample ?ow rate and elution conditions were investigated and discussed. Common coexisting ions did not seriously interfere with the separation, showing the good selectivity of the proposed method. The calibration graph was linear in the range of 0.35–70, 0.50–80, 0.9–100, 0.55–75, 0.75–90 and 1.0–120 ng mL^?1 for Fe-CMBM, Fe-DDTC, Fe-APDC, Zn-CMBM, Zn-DDTC and Zn-APDC, respectively. Under optimized conditions, the limits of detection were 0.11, 0.13, 0.27, 0.16, 0.22 and 0.30 ng mL^?1 for Fe-CMBM, Fe-DDTC, Fe-APDC, Zn-CMBM, Zn-DDTC and Zn-APDC, respectively. The proposed method has been applied to the determination of Fe(III) and Zn(II) in different water samples with satisfactory recovery percentages. The developed method, validated with standard reference materials, was used successfully in determining the concentrations of metal ions in water samples.     

Combining continuous catalytic regenerative naphtha reformer with thermally coupled concept for improving the process yield

Advancements in the catalytic naphtha reforming process, as one of the main processes in petrochemical industry, contributed to development of continuous catalytic regenerative naphtha reformer units. Increasing the yield of aromatic and hydrogen as well as saving the energy in this process through the application of thermal coupling technique is a potentially interesting idea. This novel idea has been assessed in this paper. In the proposed configuration, continuous catalyst regeneration naphtha reforming process is coupled with hydrogenation of nitrobenzene in a two co-axial reactor separated by a solid wall, where the generated heat in nitrobenzene hydrogenation reaction transfers to naphtha reforming reaction medium through the surface of the tube. A steady-state, homogeneous, two-dimensional model is used to describe the performance of this configuration and a kinetic model including 32 pseudo-components with 84 reactions is considered for naphtha reforming reaction. After validating the model with the commercial data of a domestic plant, the obtained results of coupled reactor are compared by the conventional one. The obtained results show the superiority of CCR coupled reactor against the conventional one.     

Citywide: Supporting Interactive Digital Experiences Across Physical Space

The Citywide project is exploring ways in which technology can provide people with rich and engaging digital experiences as they move through physical space, including historical experiences, performances and games. This paper describes some initial results and experiences with this project based upon two prototype demonstrators. In the first, we describe an application in which a search party explores an archaeological site, uncovering enacted scenes within the virtual world that are of a historical relevance to their particular physical location. In the second, we describe a museum experience where participants explore an outdoors location, hunting for buried virtual artifacts that they then bring back to a museum for a more detailed study. Our demonstrators employ a varied set of devices, including mobile wireless interfaces for locating hotspots of virtual activity when outdoors, to give different experiences of the virtual world depending upon location, task, available equipment and accuracy of tracking. We conclude by discussing some of the potential advantages of using an underlying shared virtual world to support interactive experiences across extended physical settings.     

Queue Analysis and Multiplexing of Heavy-tailed Traffic in Wireless Packet Data Networks

Recent research based on traffic measurements shows that Internet traffic flows have a fractal nature (i.e., self-similarity property), which causes an underestimation of network engineering parameters when using the conventional Poisson model. Preliminary field measurements demonstrate that packet data traffic in wireless communications also exhibits self-similarity. In this paper, we investigate the queuing behavior of self-similar traffic flows for data applications in a packet-switching single-server wireless network. The traffic is generated by an on–off source with heavy-tailed on periods and exponentially distributed off periods. We extend previous analysis of a relation among the asymptotic distribution of loss probability, traffic specifications, and transmission rate for a wireline system to a wireless system, taking into account wireless propagation channel characteristics. We also investigate the multiplexing of heavy-tailed traffic flows with a finite buffer for the downlink transmission of a wireless network. Computer simulation results demonstrate that assumptions made in the theoretical analysis are reasonable and the derived relationships are accurate.     

On Confinement of the Initial Location of an Intruder in a Multi-robot Pursuit Game

Research in multi-robot pursuit-evasion demonstrates that three pursuers are sufficient to capture an intruder in a polygonal environment. However, this result requires the confined of the initial location of the intruder within the convex hull of the locations of the pursuers. In this study, we extend this result to alleviate this convexity through the application of a set of virtual goals that are independent of the locations of the pursuers. These virtual goals are solely calculated using the location information of the intruder such that whose locations confine the intruder within their convex hull at every execution cycle. We propose two strategies to coordinate the pursuers. They are the agents votes maximization and the profile matrix permutations strategies. We consider the time, the energy expended, and the distance traveled by the pursuers as metrics to analyze the performance of these strategies in contrast to three different allocation strategies. They are the probabilistic, the leader-follower, and the prioritization coordination strategies.     

Fault localization algorithm in computer networks by employing a genetic algorithm

Abstract

Fault localization is an important part in communication networks. Faults are unwanted and unavoidable in communication systems, and hence, their quick detection and localization is essential for sustaining the health of the network. This paper proposes an end-to-end approach that uses passive measurements for fault localization in communication networks. We formulate the fault localisation issue as an optimisation problem and then employ the genetic algorithm technique to solve it. Extensive simulation results show that although our algorithm needs to test only a small set of network components to localise all faults, it can infer the faulty nodes in at least 97% of cases. This simulation shows that the proposed algorithm, called genetic algorithm-based fault localisation is superior to the other approaches to localise all faults in a network.     

Methodology for in-line rheology by ultrasound Doppler velocity profiling and pressure difference techniques

This paper describes a methodology for measuring rheological flow properties in-line, in real-time, based on simultaneous measurements of velocity profiles using an ultrasound velocity profiling (UVP) technique with pressure difference (PD) technology. The methodology allows measurements that are rapid, non-destructive and non-invasive and has several advantages over methods presented previously. The set-up used here allows direct access to demodulated echo amplitude data, thus providing an option to switch between time domain algorithms and algorithms based on FFT for estimating velocities, depending on the signal-to-noise ratio (SNR) and time resolution required. Software based on the MATLAB^® graphical user interface (GUI) has been developed and provides a powerful and rapid tool for visualizing and processing the data acquired, giving rheological information in real-time and in excellent agreement with conventional methods. This paper further focuses on crucial aspects of the methodology: implementation of low-pass filter and singular value decomposition (SVD) methods, non-invasive measurements and determination of the wall positions using channel correlation and methods based on SVD. Measurements of sound velocity and attenuation of ultrasound in-line were introduced to increase measurement accuracy and provide an interesting approach to determine particle concentration in-line. The UVP-PD methodology presented may serve as an in-line tool for non-invasive, real-time monitoring and process control.     

A Novel Grounded Inductor Realization Using a Minimum Number of Active and Passive Components

In this study, we present a new topology for realizing a grounded inductor employing only a single current conveyor, called a negative‐type modified inverting second‐generation current conveyor (MICCII‐), and a minimum number of passive components, two resistors, and one capacitor. The non‐ideality effects of the MICCII‐on a simulated inductor are investigated. To demonstrate the performance of the presented inductance simulator, we use it to construct a third order Butterworth high‐pass filter and a parallel resonant circuit. Simulation results are given to confirm the theoretical analysis.