Morphological and electron mobility studies in nanograss In2O3 DSSC incorporating multi-walled carbon nanotubes

Ionics - In2O3and In2O3-MWCNTs, thin films were prepared by means of sol-gel spin coating technique for dye-sensitized solar cells (DSSCs). The morphological characteristics of In2O3 and...     

Ultrasonic-Assisted Dry Creep-Feed Up-Grinding of Superalloy Inconel738LC

Among many machining methods, grinding is the most applicable one for cutting hard-to-cut materials such as superalloys. In this research, effects of longitudinal ultrasonic vibration of workpiece (Inconel738LC) in dry creep-feed up-grinding process were investigated. Mechanism of abrasive grain and workpiece surface interaction and the consequences have been analyzed both analytically and numerically. Then, the results have been compared with experimental findings. Analytical calculations showed that there is a multiple and discontinuous cutting along the contact zone of grinding wheel and the workpiece when longitudinal ultrasonic vibration is used. Two-dimensional finite element modeling in commercial MSC.Superform software, showed the same behavior and results. Grinding forces are one of the major output parameters for evaluations. It was observed that, application of ultrasonic vibration can decrease grinding forces. A practical decrease of up to 27% of vertical grinding forces and up to 22% of horizontal grinding forces has been achieved when using ultrasonic vibration. Finite-Element analysis has shown a reduction of about 40% of grinding forces compared with ordinary grinding. Probable lower risks of thermal damage even for working under dry conditions can be a big advantage of using ultrasonic with grinding.     

Rainwater rivulets on a cable subject to windFilets d'eau de pluie sur un câble soumis au vent

Rainwater rivulets appear on inclined cables of cable-stayed bridges when wind and rain occur simultaneously. In a restricted range of parameters this is known to cause vibrations of high amplitudes on the cable. The mechanism underlying this effect is still under debate but the role of rainwater rivulets is certain. We use a standard lubrication model to analyse the dynamics of a water film on a cylinder under the effect of gravity and wind load. A simple criterion is then proposed for the appearance and position of rivulets, where the Froude number is the control parameter. Experiments with several geometries of cylinder covered with water in a wind tunnel show the evolution of the rivulets with the Froude number. Comparison of the prediction by the model with these experimental data shows that the main mechanism of rivulet formation and positioning is captured. To cite this article: C. Lemaitre et al., C. R. Mecanique 334 (2006).     

Quality of service management for IPTV services support in VANETs: a performance evaluation study

In order to deliver a qualitative Internet Protocol Television (IPTV) service over vehicular ad hoc networks (VANETs), a quality of service (QoS) mechanism is needed to manage the allocate of network resources to the diverse IPTV application traffic demands. Unlike other mobile network, VANETs have certain unique characteristic that presents several difficulties in providing an effective QoS. Similarly, IPTV requires a constant stream for QoS which at the moment is quite difficult due to the inherent VANET characteristics. To provide an effective QoS that will meet the IPTV application service demands, VANETs, must satisfy the compelling real-time traffic streaming QoS requirement (i.e., minimum bandwidth allocation, packet loss and jitter). In this report, we evaluate via simulation the feasibility of deploying quality IPTV services over VANETs, by characterizing the association between the IPTV streaming quality determining factors (i.e., throughput, delay, loss, jitter) and the IPTV quality degradation, with respect to node density and node velocity. Furthermore, we used an objective QoS metric (Media-Delivery-Index) to identify, locate and address the loss or out-of-order packet. We outline how, using these information’s can support in shaping network parameters to optimize service flows. The implementation assures a priority for handling IPTV traffic, such that maximise the usage of VANETs resources, and opens the possibility that loss and delay can be minimised to a degree that could guarantee quality IPTV service delivery among vehicle in a vehicular network system.

     

Benard convection in a non-linear magnetic fluid under the influence of a non-vertical magnetic field

This work examines the convective instability of a horizontal layer of magnetohydrodynamic fluid of variable permeability when subjected to a non-vertical magnetic field. We use a model proposed by P. H. Roberts [9] in the context of neutron stars but the results obtained are aso relevant to the area of ferromagnetic fluids. The presence of the variable permeability has no effect on the development of instabilities through the mechanism of stationary convection but influences the threshold of overstable convection which is often the preferred mechanism in non-terrestrial applications. In the context of ferromagnetic fluids, both stationary and overstable instability can be expected to be realisable possibilities.     

B(E2) value of even-even ~(108-112)Pd isotopes by interacting boson model-1

This work studies the systematic reduced transition probabilities B(E2)↓,intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from N=62 to 66.The downward reduced transition probabilities B(E2)↓from gamma transition 8+to 6+,6+to 4+,4+to 2+and 2+to 0+states of even-even108 112Pd isotopes were calculated by the Interacting Boson Model(IBM-1)and compared with the available previous experimental results.The ratio of the excitation energies of the first 4+and the first 2+excited states,R4/2,is also studied for the classification of symmetry of these nuclei.Furthermore we have studied systematically the transition rate R=B(E2:L+→(L 2)+)/B(E2:2+→0+)of some of the low-lying quadrupole collective states in comparison with the available experimental data.The associated quadrupole moments and deformation parameters have been calculated.The results of this calculation are in good agreement with the corresponding available experimental data.The108 112Pd isotopes show the O(6)symmetry.     

Monolithic QW laser beam steering and wavelength tunability

We demonstrate a monolithic tunable laser on a QW structure by integrating an optical beam steering section with an area-selectively intermixed QW gain section. Wavelength switching is achieved by steering the laser beam over an optical gain medium that consists of two laterally adjacent quantum well regions selectively intermixed to varying extents. The device output had a total of 10 nm wavelength tuning that was controlled by injecting separate electrical current values to each of the steering contacts and the amplifier contact.