Immobilization of cytochrome c on polyaniline/polypyrrole/carboxylated multi-walled carbon nanotube/glassy carbon electrode: biosensor fabrication

Journal of Solid State Electrochemistry - A modified electrode PAN/PPY/cMWCNTs composed of polyaniline/polypyrrole (PAN/PPY) bilayer conducting polymer film, carboxylated multi-walled carbon...     

Improved photocatalytic degradation of reactive blue 81 using NiO-doped ZnO–ZrO2 nanoparticles

In this study, the photocatalytic degradation of Reactive Blue 81 (RB81) using synthesized NiO-doped ZnO–ZrO₂ nanoparticles under UV irradiation was investigated. Then, the products were characterized by Scanning electron microscope (SEM), X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS). The removal rate of RB81 using ZnO–ZrO₂ after 180?min of irradiation was 96.7%. Nickel oxide (NiO) was used as an additive to ZnO–ZrO₂ for improvement of RB81 degradation via photocatalysis process. Photodegradation of RB81 was achieved to 100% using ZnO–ZrO₂–NiO nanoparticles with ratio of 1:2:0.3 after 180?min of irradiation. There was a red shift in absorption bands (from 410?nm to 435?nm) observed in increasing of NiO to ZnO–ZrO₂ nanoparticle, that it might lead to a higher photocatalytic activity under visible light. Response surface methodology (RSM) was used for optimization of experimental and these results were obtained: solution pH = 3, ZnO–ZrO₂–NiO dosage = 15?mg/L, and the initial RB81 concentration = 5?mg/L. The photodegredation of RB81 followed pseudo-first order kinetic according to the Langmuir–Hinshelwood model.     

Feasibility study on optimization of a typical solar chimney power plant

The solar chimney which has been built in Kerman (Kerman city-Iran) is a small scale electrical power plant. The chimney of this unit has 60 m height and 3 m diameter. The collector of this unit is 40 m × 40 m square. To reach nominal power of this unit of power plant, parameters which are effective in optimization are studied. In this regard, we deliberate and propose suggestions to maximize usage of solar energy and kinetic energy. The calculation of maximum power is one of the objectives of this study, so the paper present economic analysis for Kerman solar chimney. A home code has been written for this modeling, in MATLAB.     

Spin-valley Hall conductivity of doped ferromagnetic silicene under strain

The spin-valley Hall conductivity(SHC-VHC) of two-dimensional material ferromagnetic graphene's silicon analog,silicene, is investigated in the presence of strain within the Kubo formalism in the context of the Kane–Mele Hamiltonian.The Dirac cone approximation has been used to investigate the dynamics of carriers under the strain along the armchair(AC) direction. In particular, we study the effect of external static electric field on these conductivities under the strain.In the presence of the strain, the carriers have a larger effective mass and the transport decreases. Our findings show that SHC changes with respect to the direction of the applied electric field symmetrically while VHC increases independently.Furthermore, the reflection symmetry of the structure has been broken with the electric field and a phase transition occurs to topological insulator for strained ferromagnetic silicene. A critical strain is found in the presence of the electric field around 45%. SHC(VHC) decreases(increases) for strains smaller than this value symmetrically while it increases(decreases) for strains larger than one.     

Designing a multi-scroll chaotic system by operating Logistic map with fractal process

Recently, chaotic systems have been widely investigated in several engineering applications. This paper presents a new chaotic system based on Julia’s fractal process, chaotic attractors and Logistic map in a complex set. Complex dynamic characteristics were analyzed, such as equilibrium points, bifurcation, Lyapunov exponents and chaotic behavior of the proposed chaotic system. As we know, one positive Lyapunov exponent proved the chaotic state. Numerical simulation shows a plethora of complex dynamic behaviors, which coexist with an antagonist form mixed of bifurcation and attractor. Then, we introduce an algorithm for image encryption based on chaotic system. The algorithm consists of two main stages: confusion and diffusion. Experimental results have proved that the proposed maps used are more complicated and they have a key space sufficiently large. The proposed image encryption algorithm is compared to other recent image encryption schemes by using different security analysis factors including differential attacks analysis, statistical tests, key space analysis, information entropy test and running time. The results demonstrated that the proposed image encryption scheme has better results in the level of security and speed.     

Effect of temperature on $$\mathbf{In}_{{\varvec{x}}} \mathbf{Ga}_{1-{{\varvec{x}}}} \mathbf{As}/\mathbf{GaAs}$$ quantum dots

Analytical solution of the Dirac equation for the modified Pöschl–Teller potential and trigonometric Scarf II non-central potential for spin symmetry is studied using asymptotic iteration method. One-dimensional Dirac equation consisting of the radial and angular parts can be obtained by the separation of variables. By using asymptotic iteration method, the relativistic energy equation and orbital quantum number (l) equation can be obtained, where both are interrelated. Relativistic energy equation is calculated numerically by the Matlab software. The increase in the radial quantum number n _r causes a decrease in the energy value, and the wave functions of the radial and the angular parts are expressed in terms of hypergeometric functions. Some thermodynamical properties of the system can be determined by reducing the relativistic energy equation to the non-relativistic energy equation. Thermodynamical properties such as vibrational partition function, vibrational specific heat function and vibrational mean energy function are expressed in terms of error function.     

A product of varieties in relation to Baer invariants

The concept of the Baer invariant is useful in classifying groups into isologism classes. In this paper two sequences of varieties {^rV_n}n∈N₀ and {^lV_n}n∈N₀, are considered from a given variety V. The structure of Baer invariants of some groups with respect to these varieties, are determined for some specific V.     

Theg-factors of the 300 ps, 5/2− states in75,77As

We measured the g-factors of the 300 ps, 5/2⁻ states in^75,77As. The results are discussed in the framework of the core-excitation model.     

Autoregressive representations of multivariate stationary stochastic processes

Consider a q-variate weakly stationary stochastic process {X _n } with the spectral density W. The problem of autoregressive representation of {X _n } or equivalently the autoregressive representation of the linear least squares predictor of X _n , based on the infinite past is studied. It is shown that for every W in a large class of densities, the corresponding process has a mean convergent autoregressive representation. This class includes as special subclasses, the densities studied by Masani (1960) and Pourahmadi (1985). As a consequence it is shown that the condition W ^-1∈L _qxq ¹ or minimality of {X _n } is dispensable for this problem. When W is not in this class or when W has zeros of order 2 or more, it is shown that {X _n } has a mean Abel summable or mean compounded Cesáro summable autoregressive representation. Research supported by the NSF Grant MCS-8301240 and the AFOSR, Grant F49620 82 C0009. This work was done while the author was visiting Center for Stochastic Processes, University of North Carolina, Chapel Hill