Finite elastic deformations of transversely isotropic circular cylindrical tubes

We consider the finite radially symmetric deformation of a circular cylindrical tube of a homogeneous transversely isotropic elastic material subject to axial stretch, radial deformation and torsion, supported by axial load, internal pressure and end moment. Two different directions of transverse isotropy are considered: the radial direction and an arbitrary direction in planes normal locally to the radial direction, the only directions for which the considered deformation is admissible in general. In the absence of body forces, formulas are obtained for the internal pressure, and the resultant axial load and torsional moment on the ends of the tube in respect of a general strain-energy function. For a specific material model of transversely isotropic elasticity, and material and geometrical parameters, numerical results are used to illustrate the dependence of the pressure, (reduced) axial load and moment on the radial stretch and a measure of the torsional deformation for a fixed value of the axial stretch.     

Removal of Malachite Green Dye from Aqueous Solution by Catalytic Wet Oxidation Technique Using Ni/Kaolin as Catalyst

In this study, natural Algerian kaolin was used as a support and impregnated with nickel at different loading amounts (2 wt.%, 5 wt.%, and 7 wt.%) in order to prepare a supported catalyst. The wet impregnation technique was used in this preparation; nickel oxide (NiO) was the active phase precursor of the catalyst, and the catalysts were designated as follows: 2%, 5%, and 7% Ni/kaolin. These catalysts were put to the test in catalytic wet peroxide oxidation (CWPO) for degrading the organic contaminant malachite green dye (MG). Analytical techniques such as FTIR spectroscopy, X-ray diffraction, BET, and X-fluorescence were used to examine the structure, morphology, and chemical composition of the support and the produced catalysts. Several parameters, including temperature, catalytic dose, metal loading, hydrogen peroxide volume, and kinetic model were systematically investigated. The combination of improved parameters resulted in a significant increase in the catalytic activity, achieving a high removal rate of MG dye of 98.87%.     

Study on QoS Management for Video Streaming in Vehicular Ad Hoc Network (VANET)

Wireless Personal Communications - Vehicular Ad Hoc Network (VANET) is a particular type of MANET providing various wireless communications such as infrastructure communications and inter-vehicle...     

Network-Level QoS Assurances Through Adaptive Allocation of CDMA Resources

In a Code Division Multiple Access (CDMA) network, multiple Mobile Hosts (MHs) can simultaneously transmit over the wireless channel by using different codes. To assure an acceptable Quality of Service (QoS) for all MHs' flows, the network usually tunes the transmit powers of all MHs to achieve a certain level of signal strength as compared to the noise and the interference (SINR) for each MH. The traditional assumption in power control schemes is that the SINR requirement is statically determined for each MH's flow. In contrast, in this paper, we propose a scheme that dynamically adapts the SINR requirements of MH's flow based on its QoS requirements and the conditions of the wireless channel between the MHs and the base station. As a result of this adaptation, we show that network-level QoS measures such as fraction of packets meeting their delay requirements and energy consumed per packet transmission are significantly better than in a scheme that statically fixes the SINR requirements. We show that the adaptation approach works well for the Matched Filter (MF) and the Minimum Mean Squared Error (MMSE) receivers. Our scheme uses a simple table-driven approach for optimally selecting the target SINR requirement for each MH at run time. The entries in the table are computed off-line using a dynamic programming algorithm with the objective of maximizing a profit function that balances the need for meeting the network-level QoS requirements and the cost of using a particular target SINR for a given transmission. Moncef Elaoud (M'97) received his B.Sc. (1988) his M.Sc. (1990) and his Ph.D. (2000) in electrical an computer engineering from the University of Wisconsin-Madison. He is currently a senior research Scientist at Telcordia Technologies' Applied Research organization. His main research interests are in the areas of quality of service, self-forming and self healing networks, auto-configuration, and mobility management in wireless and ad-hoc networks. Bechir Hamdaoui received the B.S. degrees in both electrical and mechanical engineering, and the M.S. degree in mechanical engineering from the National School of Engineering in Tunis (BAC+6+DEA, ENIT), Tunisia, in 1997 and 1998, respectively. He also received the M.S. degree in electrical and computer engineering from the University of Wiconsin, Madison, WI, in 2002, where he is currently working toward the Ph.D. degree. From 1998 to 1999, he worked as a quality control and planning engineer on power generation plant project under the supervision of FIAT Avio. His research focuses on various aspects in the area of computer networking including mobile networks, wireless communication systems, and ad hoc networks. Parameswaran Ramanathan received the B. Tech degree from the Indian Institute of Technology, Bombay, India, in 1984, and the M. S. E. and Ph. D. degrees from the University of Michigan, Ann Arbor, in 1986 and 1989, respectively. Since 1989, Dr. Ramanathan has been faculty member in the Department of Electrical & Computer Engineering, University of Wisconsin, Madison, where is presently a Full Professor. He leads research projects in the areas of sensor networks and next generation cellular technology. In 1997–98, he took a sabbatical leave to visit research groups at AT&T Laboratories and Telcordia Technologies. Dr. Ramanathan's research interests include wireless and wireline networking, real-time systems, fault-tolerant computing, and distributed systems. He is presently an Associate Editor for IEEE Transactions on Mobile Computing and Elsevier AdHoc Networks Journal. He served as an Associate Editor for IEEE Transactions on Parallel and Distributed Computing from 1996–1999. He has also served on program committees of conferences such as Mobicom, Mobihoc, International Conferences on Distributed Systems and Networks, Distributed Computing Systems, Fault-tolerant Computing Symposium, Real-time Systems Symposium, Conference on Local Computer Networks, and International Conference on Engineering Complex Computer Systems. He was the Finance and Registration Chair for the 1999 Fault-tolerant Computing Symposium. He was the program chairman of the Workshop on Architectures for Real-time Applications, 1994 and the program vice-chair for the International Workshop on Parallel and Distributed Real-time Systems, 1996. He is a member of Association of Computing Machinery and a senior member of IEEE.     

A network-layer soft handoff approach for mobile wireless IP-based systems

Handoff is the process during which a mobile node (MN) needs to change its connectivity point to the wireless internetwork from one access node (AN) to another during an ongoing communication. If MNs are allowed to have two or more simultaneous connections to the internetwork through different ANs, then the handoff is said to be soft; otherwise, it is said to be hard. Traditionally, during forward-link soft handoff, multiple identical copies of each packet are simultaneously transmitted to the MN through the associated ANs. At the MN's physical-layer, the received signals are combined on a bit-by-bit basis resulting in improving the bit-error rate. However, this approach requires tight synchronization of the ANs involved in the soft handoff. In addition, as shown in the literature, the capacity often decreases due to the increase of the number of channels used by MNs during soft handoff. In this paper, we propose, analyze, simulate, and implement a soft handoff scheme called soft handoff over IP (SHIP) for forward-link that 1) overcomes the need for synchronization and 2) increases the capacity of the network. Through both analytic and simulation studies, we show that SHIP achieves significant performance improvements. We derive analytic expressions of the power-capacity relationship for two-dimensional (2-D) and one-dimensional (1-D) cell models. By comparing our scheme with the hard handoff, we empirically show that the capacity increases by about 30% and 20%, respectively, for the 2-D and 1-D cell models. Further, the simulation results show that SHIP saves up to 30% of the total power consumed by the ANs.     

Chemosensing Properties of Coumarin Derivatives: Promising Agents with Diverse Pharmacological Properties,Docking and DFT Investigation

In this work, a three-component reaction of 3-acetyl-4-hydroxycoumarine, malononitrile, or cyanoacetate in the presence of ammonium acetate was used to form coumarin derivatives. The chemical structures of new compounds were identified by ¹H, ¹³C NMR and an elemental analysis. These compounds were examined in vitro for their antimicrobial activity against a panel of bacterial strains. In addition, these compounds were investigated for antioxidant activities by superoxideradical, DPPH (2,2-Diphenyl-1-picrylhydrazyl), and hydroxyl radical scavenging assays, in which most of them displayed significant antioxidant activities. Furthermore, these compounds were evaluated for anti-inflammatory activity by indirect hemolytic and lipoxygenase inhibition assays and revealed good activity. In addition, screening of the selected compounds 2–4 against colon carcinoma cell lines (HCT-116) and hepatocellular carcinoma cell lines (HepG-2) showed that that 2-amino-4-hydroxy-6-(4-hydroxy-2-oxo-2H-chromen-3-yl)nicotinonitrile 4 exhibited good cytotoxic activity against standard Vinblastine, while the other compounds exhibited moderate cytotoxic activity. Docking simulation showed that2-amino-4-hydroxy-6-(4-hydroxy-2-oxo-2H-chromen-3-yl)nicotinonitrile 4 is an effective inhibitor of the tumor protein HCT-116. A large fluorescence enhancement in a highly acidic medium was observed, and large fluorescence quenching by the addition of traces of Cu²⁺ and Ni²⁺ was also remarked.     

Ultrasonication-assisted sorption of cadmium from aqueous phase by wheat bran

In the present study, the sorption of cadmium from aqueous phase by wheat bran was investigated with and without the assistance of ultrasound. Kinetic data and sorption equilibrium isotherms were carried out in batch conditions. The influence of different operating parameters such as ultrasonic power, cadmium initial concentration, sorbent mass, temperature, and the combination of ultrasound and mechanical stirring on the kinetics of cadmium removal was studied. The obtained results show that the ultrasonic irradiation significantly enhances and improves the efficiency of the removal of cadmium, especially in the combined method. The sorption kinetic data were found to be well-represented by the pseudo-second-order rate equation, both in the absence and presence of ultrasound as well as in the combined process (stirring and ultrasonication). Ultrasonic power played a key role in the removal of cadmium. Equilibrium isotherm results could be well described by the Langmuir model both with and without the assistance of ultrasound. The effect of temperature on the sorption isotherms of cadmium in the absence and presence of ultrasound has been also studied and the thermodynamic parameters DeltaG degrees, DeltaH degrees, and DeltaS degrees were determined. The monolayer sorption capacities were 51.81, 35.09, and 22.78 mg g(-1) for experiments conducted by the combined process, in the presence of ultrasound, and in passive conditions, respectively. The combination ultrasound-stirring for the sorption process was shown to be of interest for the treatment of wastewaters contaminated with cadmium.