Fully digital jerk-based chaotic oscillators for high throughput pseudo-random number generators up to 8.77 Gbits/s

This paper introduces fully digital implementations of four different systems in the 3rd order jerk-equation based chaotic family using the Euler approximation. The digitization approach enables controllable chaotic systems that reliably provide sinusoidal or chaotic output based on a selection input. New systems are introduced, derived using logical and arithmetic operations between two system implementations of different bus widths, with up to 100× higher maximum Lyapunov exponent than the original jerk-equation based chaotic systems. The resulting chaotic output is shown to pass the NIST SP. 800-22 statistical test suite for pseudo-random number generators without post-processing by only eliminating the statistically defective bits. The systems are designed in Verilog HDL and experimentally verified on a Xilinx Virtex 4 FPGA for a maximum throughput of 15.59 Gbits/s for the native chaotic output and 8.77 Gbits/s for the resulting pseudo-random number generators.     

Performance of current controllers for VSI-fed IPMSM drive

The current-controlled voltage-source-inverter-fed interior permanent-magnet synchronous motor (IPMSM) has received widespread interest in high-precision industrial drive applications. This paper presents a detailed comparison of various current controller schemes, particularly hysteresis and ramp comparator controllers for the IPMSM drive based on performance at different speeds. The hysteresis and the ramp comparator controllers are getting more attention due to their simplicity and high dynamic responses. In this paper, fixed, sinusoidal, and mixed-band hysteresis current controllers, as well as conventional ramp and improved ramp comparator controllers, are considered. The harmonic spectra of the motor line currents for various current controllers are obtained using a fast Fourier transform for comparison purposes. The comparison is based on experimental results. In order to compare the performance of various controllers, the complete drive system is implemented in real time using the digital signal processor controller board DS-1102.     

Effect of electron irradiation on alternating current electrical properties of gelatin – cadmium sulfide nano-composite films

Gelatin was doped with 1 %, 3 %, 5 % and 10 % cadmium sulfide nanoparticles in weight concentrations forming the gelatin-cadmium sulfide nanocomposites and irradiated by various electron beam doses equals 50 kGy, 75 kGy, 100 kGy, and 150 kGy using 3 MeV – 3 mA electron accelerator. The applied alternating current electrical field frequency ranging from 70 Hz to 5 MHz is what caused the fluctuation in dielectric properties and alternating current electrical conductivity of these nanocomposites. The results showed that the films of 1 %, 3 %, 5 %, and 10 % for blank (nanocomposite film without electron beam irradiation) nanocomposites had the highest dielectric parameters (έ, ϵ′′, tan δ) at 0.5 kHz with values of (0.696, 0.0233, 0.034), (0.533, 0.0114, 0.0215), (0.402, 0.001196, 0.003), and (0.459, 0.00418, 0.0091), respectively. However, the lowest dielectric parameters were (0.645, 0.00618, 0.0066), (0.523, 0.00165, 0.0215), (0.417, 0.00035, 0.0008), and (0.455, 0.00066, 0.0015) at 5 MHz, respectively. The highest conductivity values for blank nanocomposites of 1 %, 3 %, 5 %, and 10 % were 1.79×10⁻⁴ S/m, 1.45×10⁻⁴ S/m, 1.16×10⁻⁴ S/m, 1.27×10⁻⁴ S/m at 5 MHz, and the lowest values were 1.92×10⁻⁸ S/m, 1.49×10⁻⁸ S/m, 1.13×10⁻⁸ S/m, 1.26×10⁻⁸ S/m at 0.5 kHz, respectively. For irradiated nanocomposites at 5 MHz, the dielectric constant order for 1 % was 100 kGy, 150 kGy, 50 kGy, and 75 kGy with values 0.63, 0.537, 0.532, and 0.523, respectively. For 10 % weight concentration, the order was 50 kGy, 100 kGy, 150 kGy, and 75 kGy with values 0.515, 0.477, 0.47, and 0.437, respectively. Otherwise the dielectric constant order for 3 % and 5 % was 100 kGy, 75 kGy, 150 kGy, and 50 kGy. The highest dielectric properties and conductivity values for blank and irradiated nanocomposites were observed at 100 kGy for 1 %, 3 %, and 5 %.     

Thickness-dependence of stoichiometry and microstructure characteristics in correlation with conductivity type of CdTe films

CdTe films were prepared by physical vapour deposition on a substrate at room temperature (RT) as well as on a cold (LT) one using low deposition rate. The thickness-dependence of stoichiometry revealed an abrupt decrease in the Cd/Te ratio as the thickness increases. Change of thickness did not affect the type of observed (111) crystallographic texture, only the degree of preferred orientation is enhanced as the film grows. The internal strain was negligible while the crystallite size increased rapidly at small thickness (up to 400 nm), and less thickness dependence was observed with further film growth. However, thickness dependence of lattice parameters showed a minimum and a maximum at approximately 300 nm in the case of RT and LT, respectively. The observed change in conductivity from n- to p-type and its vital correlation with the stoichiometry and structural characteristics were presented. Based on thickness dependence of stoichiometry and lattice parameters as well as the conductivity type, formation and annihilation of lattice defects were considered.     

Computerized relational model for powder technology: powder and process selection

Part of a complete expert-system software design for powder technology is presented. This part of the system deals with powder selection according to predetermined, recommended or required material properties, and specific powder characteristics. Then the optimum powder production, i.e processing, method is determined, which satisfies the requirements of the specified powder. For this purpose a detailed database relational model is developed, and the system's software modules are described. A relational model is formulated and a structured query language (SQL) is used in the detailed software design presented.     

Metabolomic Identification of Anticancer Metabolites of Australian Propolis and Proteomic Elucidation of Its Synergistic Mechanisms with Doxorubicin in the MCF7 Cells

The combination of natural products with standard chemotherapeutic agents offers a promising strategy to enhance the efficacy or reduce the side effects of standard chemotherapy. Doxorubicin (DOX), a standard drug for breast cancer, has several disadvantages, including severe side effects and the development of drug resistance. Recently, we reported the potential bioactive markers of Australian propolis extract (AP-1) and their broad spectrum of pharmacological activities. In the present study, we explored the synergistic interactions between AP-1 and DOX in the MCF7 breast adenocarcinoma cells using different synergy quantitation models. Biochemometric and metabolomics-driven analysis was performed to identify the potential anticancer metabolites in AP-1. The molecular mechanisms of synergy were studied by analysing the apoptotic profile via flow cytometry, apoptotic proteome array and measuring the oxidative status of the MCF7 cells treated with the most synergistic combination. Furthermore, label-free quantification proteomics analysis was performed to decipher the underlying synergistic mechanisms. Five prenylated stilbenes were identified as the key metabolites in the most active AP-1 fraction. Strong synergy was observed when AP-1 was combined with DOX in the ratio of 100:0.29 (w/w) as validated by different synergy quantitation models implemented. AP-1 significantly enhanced the inhibitory effect of DOX against MCF7 cell proliferation in a dose-dependent manner with significant inhibition of the reactive oxygen species (p < 0.0001) compared to DOX alone. AP-1 enabled the reversal of DOX-mediated necrosis to programmed cell death, which may be advantageous to decline DOX-related side effects. AP-1 also significantly enhanced the apoptotic effect of DOX after 24 h of treatment with significant upregulation of catalase, HTRA2/Omi, FADD together with DR5 and DR4 TRAIL-mediated apoptosis (p < 0.05), contributing to the antiproliferative activity of AP-1. Significant upregulation of pro-apoptotic p27, PON2 and catalase with downregulated anti-apoptotic XIAP, HSP60 and HIF-1α, and increased antioxidant proteins (catalase and PON2) may be associated with the improved apoptosis and oxidative status of the synergistic combination-treated MCF7 cells compared to the mono treatments. Shotgun proteomics identified 21 significantly dysregulated proteins in the synergistic combination-treated cells versus the mono treatments. These proteins were involved in the TP53/ATM-regulated non-homologous end-joining pathway and double-strand breaks repairs, recruiting the overexpressed BRCA1 and suppressed RIF1 encoded proteins. The overexpression of UPF2 was noticed in the synergistic combination treatment, which could assist in overcoming doxorubicin resistance-associated long non-coding RNA and metastasis of the MCF7 cells. In conclusion, we identified the significant synergy and highlighted the key molecular pathways in the interaction between AP-1 and DOX in the MCF7 cells together with the AP-1 anticancer metabolites. Further in vivo and clinical studies are warranted on this synergistic combination.     

Development of Poly(aniline-co-o-toluidine)/TiO2 nanocomposite coatings for low carbon steel corrosion in 3.5% NaCl solution

Chemical oxidative polymerization of aniline (AN) and o-toluidine (OT) for the synthesis of copolymer, Poly(AN-co-OT) and its composite with TiO₂ nanoparticles, Poly(AN-co-OT)/TiO₂ employing ammonium persulfate as an oxidant and HCl as an external dopant were carried out. The homopolymers, Polyaniline and Poly(o-toluidine) were also prepared by following similar method. The synthesized polymers were characterized with FTIR spectroscopy, XRD/SEM/TEM analysis. The anticorrosive coatings were synthesized in dimethyl sulfoxide solution by dissolving synthesized polymers, and then were applied on low-carbon steel (LCS) samples using epoxy binder. The anticorrosive potential of the polymer coatings containing copolymer, copolymer-nanocomposite and homopolymers on LCS was evaluated in 3.5% NaCl at a temperature of 30?°C by open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization measurements. It was observed that the nanocomposite coating increases the protection efficacy by providing better barrier properties against corrosion as compared with neat copolymer and homopolymers coatings. The morphology of the coatings before and after 60 days LCS immersion in 3.5% NaCl solution was determined using SEM.