Order and pole locator estimation in fractional order systems using bode diagram

This paper deals with estimation of fractional order and pole locator in fractional order systems. The estimation is based on Bode diagram of the system that is obtained using input and output measurements. Here the magnitude diagram is approximated with number of straight lines depending on the level of complexity and in consequence a very good estimation of fractional order and acceptable approximations of pole locators are determined. Relying on the proposed method, complexity of fractional order system identification which is mostly due to the estimation of fractional order is substantially resolved. Some example simulation results are provided to explain the work and show its effectiveness.     

Development of an inductive encoder for simultaneous measurement of two-dimensional displacement

Two-dimensional measurements are usually performed by two one-dimensional devices. In this paper, a simple method is developed, which can directly measure the displacements in two dimensions. The measurement is based on inductive method where a flat coil moves on another flat coil and the induced voltages give the displacements in x and y directions. In this research, five flat coils with special patterns are used. One is stationary and four others make the moving part. When moving part moves on the stationary surface, two of the moving coils detect the displacement in x direction and the other two detect the displacement in y direction. The patterns of the coils are designed in a way that there is no interference between axes, i.e., movement in one dimension has no effect on data of other dimension. The experimental results show the effectiveness of the concept. Resolution of 10 μm and no interference between axes are achieved. Better resolution is expected if more precise experimental device is provided.     

Optimization of Microwave-Assisted Extraction Procedure to Determine Metal in Fish Muscles Using Box–Behnken Design

This study describes the application of response surface methodology (RSM) to develop a method for zinc, lead, manganese, nickel, iron, and copper determination by flame atomic absorption spectrometry in Snow trout (Schizothorax zarudnyi) samples after extraction by a microwave system. The effects of various parameters such as irradiation power, temperature, extraction time, and concentration of nitric acid were investigated by a fractional factorial design (2⁴⁻¹) to determine the significant parameters and their interactions. The results showed that all of the parameters were significant (p < 0.05). The RSM, based on Box–Behnken design, was employed to obtain the optimum conditions of the significant parameters. The optimal conditions could be obtained at a power of 685.0 W, temperature of 116 °C, extraction time of 38.0 min, and 2.5 (mol L⁻¹) for nitric acid concentration. The method was applied for determination of zinc, lead, manganese, nickel, iron, and copper in Snow trout (Schizothorax zarudnyi) samples.     

A comparative study on anti-UV non-spherical methacrylate polymer particles and anti-UV PVA nanofibers

Three types of anti-UV non-spherical polymer particles (AUNSPP) based on methacrylate and anti-UV PVA nanofiber were synthesized to study and compare their UV protection properties. In the first type of AUNSPP, polystyrene seeds were swollen with dichloromethane solution of 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl) phenol (TINUVIN^® 234, which hereafter is called TINUVIN), styrene, divinylbenzene, and 2,2′-azobisisobutyronitrile (AIBN). In the other two types of AUNSPP, poly(methyl methacrylate) seeds were swollen with dichloromethane solution of TINUVIN, methyl methacrylate, lauryl methacrylate, ethylene glycol dimethylacrylate, and AIBN. Subsequently, dichloromethane was evaporated from the swollen microspheres, and polymerization was accomplished by elevating the temperature of swollen particles to 70 °C. The final particles were assigned as P(S)/TINUVIN, P(S-DVB)/TINUVIN, P(LMA–EGDMA)/TINUVIN, and P(MMA–EGDMA)/TINUVIN composite microspheres. Anti-UV PVA nanofibers were prepared by dispersing P(S-DVB)/TINUVIN microparticles in PVA aqueous solution. Finally, this mixture was electrospun under ambient conditions. Particle size, size distribution, and morphology of the particles were investigated by SEM micrograph and image analyzer software (Image J). The presence of TINUVIN in P(S-DVB)/TINUVIN composite particles was confirmed by FTIR and phosphorescence spectroscopy. The UV protective properties of microcomposite particles and anti-UV nanofibers were studied by UV–Vis spectra of their polyurethane (PU) composite film. Comparatively, similar cutoff wavelength effects were observed in the range of 200–400 nm in all the samples. The obtained results showed consistent drop in the UV-blocking efficiency as the UV irradiation time increased. PU/PS/TINUVIN and PU/anti-UV nanofiber composite films showed the worst and best UV-blocking efficiency, respectively. After 200, 400, 600, 800, and 1000 h of UV irradiation time, the blocking efficiency of the PU–PS/TINUVIN composite films dropped from 80 to 72, 68, 65, and 59 %, and that of the PU/anti-UV nanofiber composite films dropped from 98 to 97, 94, 86, and 83 %.     

Mathematical Modeling and Simulation of Drying Using Two Industrial Concurrent and Countercurrent Rotary Dryers for Ammonium Nitrate

Drying of ammonium nitrate (AN) is accomplished in the Shiraz Petrochemical Complex (SPC) using a concurrent rotary dryer following a countercurrent rotary dryer. A mathematical model for these rotary dryers including heat and mass transfer was developed. The model was checked against industrial-scale data, which showed a good agreement. The average absolute deviation of the simulation results compared to the industrial data for the concurrent dryer was 4.0% for solids moisture, 1.3% for solids temperature, and 1.8% for air temperature and for the countercurrent dryer it was 9.0% for the solids moisture, 2.0% for solids temperature, and 4.6% for air temperature. These simulation results reveal that for outlet solid moisture, inlet AN moisture, and air temperature as well as the outlet temperature of product, the inlet solid and air temperature have major effects for both concurrent and countercurrent flow.     

Oxidative Stress and Neurodegenerative Disorders

Living cells continually generate reactive oxygen species (ROS) through the respiratory chain during energetic metabolism. ROS at low or moderate concentration can play important physiological roles. However, an excessive amount of ROS under oxidative stress would be extremely deleterious. The central nervous system (CNS) is particularly vulnerable to oxidative stress due to its high oxygen consumption, weakly antioxidative systems and the terminal-differentiation characteristic of neurons. Thus, oxidative stress elicits various neurodegenerative diseases. In addition, chemotherapy could result in severe side effects on the CNS and peripheral nervous system (PNS) of cancer patients, and a growing body of evidence demonstrates the involvement of ROS in drug-induced neurotoxicities as well. Therefore, development of antioxidants as neuroprotective drugs is a potentially beneficial strategy for clinical therapy. In this review, we summarize the source, balance maintenance and physiologic functions of ROS, oxidative stress and its toxic mechanisms underlying a number of neurodegenerative diseases, and the possible involvement of ROS in chemotherapy-induced toxicity to the CNS and PNS. We ultimately assess the value for antioxidants as neuroprotective drugs and provide our comments on the unmet needs.