A slant on warped extra dimensions

We propose an orbifolded, warped, extra dimension scenario in which the visible brane is not parallel to the hidden brane. This leads automatically to Lorentz violation in the visible, four-dimensional world. The background solution to the Einstein equations is a function of a parameter that can be identified with the amount of ‘tilting’ of the brane. The cosmological constant is found to coincide with the classic Randall–Sundrum value to the first order in this tilt. Lorentz violating effects induced in the Standard Model are considered. We find that the strongest constraint on the tilt comes from determinations of the electron–proton mass ratio in six quasar spectra (four optical and two radio). Measurements of a third radio source could improve this by an order of magnitude.     

Peristaltic transport and heat transfer of a MHD Newtonian fluid with variable viscosity

The influence of temperature‐dependent viscosity and magnetic field on the peristaltic flow of an incompressible, viscous Newtonian fluid is investigated. The governing equations are derived under the assumptions of long wavelength approximation. A regular perturbation expansion method is used to obtain the analytical solutions for the velocity and temperature fields. The expressions for the pressure rise, friction force and the relation between the flow rate and pressure gradient are obtain. In addition to analytical solutions, numerical results are also computed and compared with the analytical results with good agreement. The results are plotted for different values of variable viscosity parameter β, Hartmann number M, and amplitude ratio ?. It is found that the pressure rise decreases as the viscosity parameter β increases and it increases as the Hartmann number M increases. Finally, the maximum pressure rise (σ=0) increases as M increases and β decreases. Copyright © 2009 John Wiley & Sons, Ltd.     

Location-allocation models for traffic police patrol vehicles on an interurban network

This research investigates the traffic police routine patrol vehicle (RPV) assignment problem on an interurban road network through a series of integer linear programs. The traffic police RPV’s main task, like other emergency services, is to handle calls-for-service. Emergency services allocation models are generally based on the shortest path algorithm however, the traffic police RPV also handles other roles, namely patrolling to create a presence that acts as a deterrence, and issuing tickets to offenders. The RPVs need to be located dynamically on both hazardous sections and on roads with heavy traffic in order to increase their presence and conspicuousness, in an attempt to prevent or reduce traffic offences, road accidents and traffic congestion. Due to the importance of the traffic patrol vehicle’s location with regard to their additional roles, allocation of the RPVs adheres to an exogenous, legal, time-to-arrival constraint. We develop location-allocation models and apply them to a case study of the road network in northern Israel. The results of the four models are compared to each other and in relation to the current chosen locations. The multiple formulations provide alternatives that jointly account for road safety and policing objectives which aid decision-makers in the selection of their preferred RPV assignments. The results of the models present a location-allocation configuration per RPV per shift with full call-for-service coverage whilst maximizing police presence and conspicuousness as a proxy for road safety.     

Simulation of the Second Grade Fluid Model for Blood Flow through a Tapered Artery with a Stenosis

We analyze the blood flow through a tapered artery, assuming the blood to be a second order fluid model. The resulting nonlinear implicit system of partial differential equations is solved by the perturbation method. The expressions for shear stress, velocity, flow rate, wall shear stress and longitudinal impedance are obtained. The physical behavior of different parameters is also discussed, as are trapping phenomena.     

Cross Section of Heavy Ion Reaction （14.5 MeV/u） ^132Xe ＋ Bi

We investigate the cross section of the heavy ion reaction （14.5 MeV/u） ^132Xe ＋ Bi by using a CR-39 plastic track detector. The target-detector assembly is exposed at UNILAC beam facility of GSI, Germany. After etching under appropriate etching conditions, the detector is scanned for multipronged events produced as a result of interactions of projectile ions with target atoms. The elastic events are separated from binary events and used for the determination of the quarter-point angle. The quarter-point angle obtained is used to determine the total reaction cross section. The total experimental reaction cross section is determined by using statistics of inelastic events of two-pronged and higher multiplicity events. The experimental reaction cross sections determined by using elastic and inelastic data observed in the reaction under study are found to be in good agreement with the theoretically calculated value of reaction cross section using a sharp cutoff model.     

Partial slip effect on non-aligned stagnation point nanofluid over a stretching convective surface

The present study inspects the non-aligned stagnation point nano fluid over a convective surface in the presence of partial slip.Two types of base fluids namely water and kerosene are selected with Cu nanoparticles.The governing physical problem is presented and transformed into a system of coupled nonlinear differential equations using suitable similarity transformations.These equations are then solved numerically using midpoint integration scheme along with Richardson extrapolation via Maple.Impact of relevant physical parameters on the dimensionless velocity and temperature profiles are portrayed through graphs.Physical quantities such as local skin frictions co-efficient and Nusselt numbers are tabularized.It is detected from numerical computations that kerosene-based nano fluids have better heat transfer capability compared with water-based nanofluids.Moreover it is found that water-based nanofluids offer less resistance in terms of skin friction than kerosene-based fluid.In order to authenticate our present study,the calculated results are compared with the prevailing literature and a considerable agreement is perceived for the limiting case.     

Low-temperature growth of ZnO nanoparticles: photocatalyst and acetone sensor

Well-crystalline ZnO nanoparticles (NPs) were synthesized in large-quantity via simple hydrothermal process using the aqueous mixtures of zinc chloride and ammonium hydroxide. The detailed structural properties were examined using X-ray diffraction pattern (XRD) and field emission scanning electron microscope (FESEM) which revealed that the synthesized NPs are well-crystalline and possessing wurtzite hexagonal phase. The NPs are almost spherical shape with the average diameters of ∼50 ± 10 nm. The quality and composition of the synthesized NPs were obtained using Fourier transform infrared (FTIR) and electron dispersed spectroscopy (EDS) which confirmed that the obtained NPs are pure ZnO and made with almost 1:1 stoichiometry of zinc and oxygen, respectively. The optical properties of ZnO NPs were investigated by UV-vis absorption spectroscopy. Synthesized ZnO NPs were extensively applied as a photocatalyst for the degradation of acridine orange (AO) and as a chemi-sensor for the electrochemical sensing of acetone in liquid phase. Almost complete degradation of AO has taken place after 80 min of irradiation time. The fabricated acetone sensor based on ZnO NPs exhibits good sensitivity (∼0.14065 μA cm⁻² mM⁻¹) with lower detection limit (0.068 ± 0.01 mM) in short response time (10 s).     

Synthesis, characterizations, photocatalytic and sensing studies of ZnO nanocapsules

ZnO nanocapsules have been synthesized hydrothermally. The structural and morophological properties were investigated using X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), FTIR, Raman, EDS and UV-vis absorption spectroscopy. For the first time chemical sensing properties of the synthesized ZnO nanocapsules have been investigated by I-V technique, where chloroform is used as a target compound. The chloroform sensors show good sensitivity (0.478 μA cm⁻² mM⁻¹), lower detection limit (6.67 μM), and large linear dynamic range (LDR, 12.0 μM-12.0 mM) with good linearity (R, 0.8523) in short response time. Additionally, photocatalytic activity of the prepared capsule shaped ZnO photocatalyst was evaluated by the degradation of acridine orange. Prepared ZnO nanocapsules posses high photocatalytic activity when compared with TiO₂-UV100.