A general two-term recurrence and its solution

We find a general explicit formula for all sequences satisfying a two-term recurrence of a certain kind. This generalizes familiar formulas for the Stirling and Lah numbers.     

On the Stirling numbers associated with the meromorphic Weyl algebra

The generalized Stirling numbers introduced recently (Mansour and Schork, 2011 [5], Mansour et al., 2011 [6]) are considered in detail for the particular case $s=2$ corresponding to the meromorphic Weyl algebra. A combinatorial interpretation in terms of perfect matchings is given for these meromorphic Stirling numbers and the connection to Bessel functions is discussed. Furthermore, two related $q$-polynomial identities are derived.     

Optical properties of nanostructure boron doped NiO thin films

Boron doped NiO films were prepared by sol–gel method. The effects of B content on the morphological and optical properties of NiO films were studied with atomic force microscopy, and optical characterization method. The average transmittance at the visible region is reached to 75 % for lower doped films (0.1 and 0.2 % B), whereas, the recorded average value of transmittance was about 62 % for doped film with 1 % B throughout the region. The optical energy gap value for pure NiO film was found to be 3.73 eV. These values were affected by B doping with non-monotonic variation and reached to 3.64 eV for 0.1 % B doped NiO. Also, the refractive index dispersion and dielectric constants of the NiO films were studied throughout the investigated range of wavelengths. The obtained results indicate that the optical parameters of the NiO film are controlled with boron doping.     

dc and ac characterizations of electrical conducting nanoporous carbon structures based on resorcinol-formaldehyde

Structural, electrical and morphological properties of electrical conducting nanoporous carbon structures, prepared at different pyrolysis temperatures by sol–gel method, were investigated. The effect of the measurement temperature on the electrical properties of the obtained sample pyrolysed at 675 °C was studied. The imaginary and real parts of the sample impedance versus frequency, in the range of 40 Hz–100 MHz, are investigated. The Nyquist diagrams were used to identify an equivalent circuit and the fundamental parameters of the circuit are determined at different temperatures with the aim to study the contributions of the grains and boundary grains to the conductivity.     

On the hyperchaotic complex Lü system

The aim of this paper is to introduce the new hyperchaotic complex Lü system. This system has complex nonlinear behavior which is studied and investigated in this work. Numerically the range of parameter values of the system at which hyperchaotic attractors exist is calculated. This new system has a whole circle of equilibria and three isolated fixed points, while the real counterpart has only three isolated ones. The stability analysis of the trivial fixed point is studied. Its dynamics is more rich in the sense that our system exhibits both chaotic and hyperchaotic attractors, as well as periodic and quasi-periodic solutions and solutions that approach fixed points. The nonlinear control method based on Lyapunov function is used to synchronize the hyperchaotic attractors. The control of these attractors is studied. Different forms of hyperchaotic complex Lü systems are constructed using the state feedback controller and complex periodic forcing.     

Modelling and control of two robotic manipulators handling a constrained object

In this paper, the problem of modelling and controlling two manipulators handling a constrained object is addressed. At first, a reduced order dynamic model of the system is derived, and several of its properties are outlined. Using the reduced order model, an adaptive control scheme that guarantees the asymptotic convergence of the position of the object, and the forces acting on the object to their desired values is developed. Simulation results of two planar robots moving an object along a plane illustrate the effectiveness of the proposed control scheme.     

Effectiveness of dairy treated wastewater and different irrigation systems on the growth,biomass and fruiting of a Tunisian olive orchard (Olea europaea L., cv Chemlali)

Abstract

The effectiveness of dairy treated wastewater (TWW) was evaluated, in comparison with tap water (TW), on a Tunisian olive orchard (Olea europea, cv Chemlali), irrigated manually (MI) and by surface dripping (SDI). To this purpose, tree growth, biomass and fruiting were monthly tested for a one-year period. Similar trunk diameters, nodes/tree, root lengths were obtained, independently of source and system of irrigation. Also, comparable tree length and leaf area, shoots/tree and biomass, were observed between TWW and TW plants. However, such parameters improved under SDI rather than MI. Fruiting occurred only in TWW and TW trees treated by MI. Concerning growth, biomass and fruiting, TWW represented a valid alternative source for the irrigation of olive orchard, especially in Tunisia, already facing the freshwater scarcity. Monitoring of soil, TWW, fruits and oil will be required to validate the use of such effluent for olive orchard irrigation.     

Radon and radium activity concentration measurement in drinking water resources in Kurdistan Region-Iraq

Journal of Radioanalytical and Nuclear Chemistry - In this present research, twenty-five drinking water samples were collected in Erbil Governorate in the Iraqi Kurdistan Region and analyzed for...