Optimal control of fredholm integral equations

In this paper a numerical method is proposed for solving optimal control problems governed by Fredholm integral equations (OCF). The method is based upon sinc wavelet and parametrization method and transforms the problem to a nonlinear programming problem. Control function u(t) and state function are approximated by a finite combination of elements of a basis and by a finite combination of sinc wavelet respectively. Numerical examples show the validity and applicability of the proposed method

On the stabilization of a coupled fractional ordinary and partial differential equations†

We investigate the stabilization problem of a cascade of a fractional ordinary differential equation (FODE) and a fractional diffusion (FD) equation, where the interconnections are of Neumann type. We exploit the PDE back stepping method as a powerful tool for designing a controller to show the Mittag–Leffler stability of the FD-FODE cascade. Finally, numerical simulations are presented to verify the results

EFFECT OF RHODIUM INFILTRATION ON THE MICROSTRUCTURE AND PERFORMANCE OF Ni/Ce0.8Gd0.2O2-δ CERMET ANODE FOR LOW TEMPERATURE SOLID OXIDE FUEL CELL

In order to further enhance the Ni/Ce 0.8Gd0.2O2-δ (Ni/GDC20) cermet anodic performance for low temperature solid oxide fuel cell (LT-SOFC), a study was conducted on the nanostructuring of NiO/GDC composite by only once wet-infiltration of rhodium chloride precursor. By using electrochemical impedance spectroscopy (EIS) analysis, the effect of only one drop of Rh-infiltrating solution on the anodic polarization resistance was examined using symmetric Ni–GDC20|GDC20|Pt electrolyte-supported cell at 400-600 °C. Nanostructural evolution before and after H 2 reduction at 600 °C and also after anodic performance test was investigated by atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) techniques in comparison to the anode itself. Despite the fine distribution of Rh-infiltrated nanoparticles having average particle size of 11.7 nm, the results showed ineffectiveness and inability of the Rh nanoparticles to succeed in decreasing of anodic polarization resistance for H 2 oxidation reaction in LT-SOFC

Catalytically Graphitized Electrospun Carbon Nanofibers Adorned with Nickel Nanoparticles for Catalysis Applications

Catalytically graphitized electrospun carbon nanofibers adorned uniformly with fine nickel nanoparticles were successfully prepared. The procedure was based on the electrospinning technique and the use of nickel precursor to create both graphitized nanofibers and nickel nanoparticles under a relatively low-temperature heat treatment. The X-ray diffraction and Raman results clearly proved catalytic graphitization of polymer-based carbon fibers in the presence of nickel catalyst. Taking the results from scanning and transmission electron microscopies and X-ray diffraction into account, it was inferred that during the heat treatment, nickel atoms have diffused through the nanofibers and formed fine nickel nanoparticles on the surface of graphitized nanofibers to make a well stabilized heterogeneous nanostructure. The results from Brunauer–Emmett–Teller technique also showed a high surface area value of 140.2 m2g-1 for the obtained structure. All these attributes along with the fibrous and porous structure enable the product to serve as a potential candidate in the catalysis applications

Estimation of Urban Suspended Particulate Air Pollution Concentration

A critical eye on the destructive impact of air pollution in Tehran is needed as the basis for urban planning, protection policy and management. This paper is focused on modeling in the GIS (Geospatial Information System) to estimate the concentration of particulate matter (PM) in any point of a typical part of Tehran which extends over 18.2 km2 and includes the so-called “Traffic Zone”. Many important general hospitals are located in this region, some of which are within the zone. The model is built on the data obtained in 42 stations located within the region. The results strongly indicate that the concentrations of PM10, PM2.5 and PM1.0 of any points inside the region, including the traffic zone, do not meet the required international standard values. The extracted estimate values for the 22 hospitals reveal that the concentration of PM10 for “Azadi Psychic”, “Children” and “Mustafa Khomeini” hospitals are the worst, estimating from the model to be 119.42 μg/m3, 107.09 μg/m3 and 101.14 μg/m3 respectively. The percent ratio of the mean concentrations of PM10/ PM2.5/ PM1.0 in this region is found to be approximately 7: 2: 1

Impedance Characteristics of Electrospun Nylon-6/TiO₂ Nanocomposite for Humidity Sensor

Resistive relative humidity (RH) sensors were fabricated by nano composites of nylon-6 and titanium dioxide nanopowders. The results indicated that these sensors can be fabricated as a reliable, low cost and fast response instruments. Different percentages of nylon-6 and TiO2 were studied and average diameters of the resultant nanofibers were found the 80 to 120 nm. The nano composite of nylon-6/TiO nanofibers was electrospun on the interdigital gold electrode on the glass substrate. It was found that the impedance of the mat ranged from 10 Ω to 10 Ω while the relative humidity was increased from 11% RH and 97.3% at room temperature. Transition electron microscopy (TEM) and scanning electron microscopy (SEM) were used to study the morphology of the nano composite