An LO architecture with novel wide locking range,quadrature output RILFDs and ILROs for cognitive radio applications

In this paper, a wide locking range, quadrature output ring type injection locked frequency divider (ILFD) is presented for division ratios of 3 and 4. This ILFD proposes a novel injection scheme that shapes the injection signal to a proper form and provides a convenient situation for divider locking. Furthermore, two new wide locking range, low power consumption, injection locked ring oscillators (ILROs) are proposed for quadrature generation in local oscillator architectures. A novel cognitive radio quadrature local oscillator (LO) architecture is presented by utilizing the proposed ILFDs and ILROs to verify the effectiveness of the proposed circuits. Moreover, a new technique is implemented on the LO architecture to widen the frequency range without consuming any extra power. Because of using a single LC tank, this architecture is very compact. Also, it has the benefit of low power consumption and low output phase noise.     

Simulation of hydrogen distribution and effect of Engineering Safety Features (ESFs) on its mitigation in a WWER-1000 containment

In this study, thermal–hydraulic parameters inside the containment of a WWER-1000/v446 nuclear power plant are simulated in a double-ended cold leg accident for short and long times(by using CONTAIN 2.0 and MELCOR 1.8.6 codes), and the effect of the spray system as an engineering safety feature on parameters mitigation is analyzed with the former code. Along with the development of the accident from design basis accident to beyond design basis accident,the Zircaloy–steam reaction becomes the source of in-vessel hydrogen generation. Hydrogen distribution inside the containment is simulated for a long time(using CONTAIN and MELCOR), and the effect of recombiners on its mitigation is analyzed(using MELCOR). Thermal–hydraulic parameters and hydrogen distribution profiles are presented as the outcome of the investigation. By activating the spray system, the peak points of pressure and temperature occur in the short time and remain below the maximum design values along the accident time. It is also shown that recombiners have a reliable effect on reducing the hydrogen concentration below flame propagation limit in the accident localization area. The parameters predicted by CONTAIN and MELCOR are in good agreement with the final safety analysis report. The noted discrepancies are discussed and explained.     

Self-learning based image decomposition for blind periodic noise estimation: a dual-domain optimization approach

Periodic noise reduction is a fundamental problem in image processing, which severely affects the visual quality and subsequent application of the data. Most of the conventional approaches are only dedicated to either the frequency or spatial domain. In this research, we propose a dual-domain approach by converting the periodic noise reduction task into an image decomposition problem. We introduced a bio-inspired computational model to separate the original image from the noise pattern without having any a priori knowledge about its structure or statistics. From the filtering perspective, the proposed method filters out only a portion of the noisy frequencies. Some considerations have to be taken into account for computational resources (computing time and memory space) which permits reducing computation complexity without sacrificing the quality of the image reconstruction. In addition, the separator size provided in the decomposition algorithm does not depend on the image size. Experiments on both synthetic and non-synthetic noisy images have been carried out to validate the effectiveness and efficiency of the proposed algorithm. The simulation results demonstrate the effectiveness of the proposed method both qualitatively and quantitatively.

     

Optimizing Multiple-Pollutant Waste Load Allocation in Rivers: An Interval Parameter Game Theoretic Model

In this paper, a new methodology is developed for optimal multiple-pollutant waste load allocation (MPWLA) in rivers considering the main existing uncertainties. An interval optimization method is used to solve the MPWLA problem. Different possible scenarios for treatment of pollution loads are defined and corresponding treatment costs are taken into account in an interval parameter optimization model. A QUAL2Kw-based water quality simulation model is developed and calibrated to estimate the concentration of the water quality variables along the river. Two non-cooperative and cooperative multiple-pollutant scenario-based models are proposed for determining waste load allocation policies in rivers. Finally, a new fuzzy interval solution concept for cooperative games, namely, Fuzzy Boundary Interval Variable Least Core (FIVLC), is developed for reallocating the total fuzzy benefit obtained from discharge permit trading among waste load dischargers. The results of applying the proposed methodology to the Zarjub River in Iran illustrate its effectiveness and applicability in multiple-pollutant waste load allocation in rivers.     

Investigating the Optimum Operational Strategy of Energy Storage Tank by Using Particle Swarm Algorithm

Optimal design of an energy storage tank system is presented in this study. Total annual cost is considered as the objective. To minimize the total annual cost, 24 design parameters including the operational strategy of the chiller in each hour during a sample day are selected. A Particle Swarm Optimization (PSO) algorithm is used for three different strategies including partial storage (PS), full storage (FS), and variable storage (VS), separately. In addition, this procedure is performed for both electrical and absorption chillers. There was a 25.21% and 13.80% improvement in total annual cost observed in the VS strategy compared with the PS and FS strategies, respectively, in the case of an electrical chiller. Furthermore, 23.47% and 8.01% improvement in total annual cost is observed in the VS strategy compared with the PS and FS strategies, respectively, in the case of an absorption chiller. Moreover, the electrical chiller was found to be more suitable in this study but no sensible difference is observed in the FS strategy. Finally the optimum results of the PSO algorithm is compared with the Genetic Algorithm (GA) and differences are reported.     

Synthesis and characterization of some new thermally stable polyimides and copolyimides bearing bipyridine side-chain groups

A new series of polyimides and copolyimides were synthesized via reaction of new bipyridine containing diamine, 4, 6-bis(4-aminophenyl)-2, 2′-bipyridine, with commercial dianhydrides. 4, 6-bis(4-aminophenyl)-2, 2′-bipyridine was synthesized starting from condensation reactions of 4-nitro acetophenone, 4-nitrobenzadehyde and pyridacyl pyridinium iodide (Krönke salt) and reduction of the desired dinitro compound. The synthesized monomer and polymers were characterized by FT-IR, NMR and CHN elemental analysis. The physical properties of the polymers, including solubility and viscosity were studied, and the results showed acceptable solubility and good chain growth for polymers. Thermal stability of these polymers was also studied by Thermo Gravimetric Analysis (TGA). The polymers start to lose weight because of thermal degradation at about 300 °C. From Differential Scanning Calorimetry (DSC), the polymers were showed T_g between 190 and 230 °C. The morphology of these polymers was also investigated by X-ray Diffraction (XRD), and the results showed only broad reflections originated from their low crystallinities.     

Pectic acid–graphene oxide nanocomposite as an adsorbent in vortex-assisted dispersive solid-phase extraction for preconcentration of copper ion followed by flame atomic absorption spectrometry

Polymer Bulletin - An efficient, green, novel and rapid vortex-assisted dispersive solid-phase extraction (VADSPE) technique was used for the preconcentration and determination of trace levels of...     

Cross-linked poly(N-alkyl-4-vinylpyridinium) iodides as new eco-friendly inhibitors for corrosion study of St-37 steel in 1 M H2SO4

Iranian Polymer Journal - Cross-linked poly (N-alkyl-4-vinylpyridinium) iodides abbreviated as P4-VPMI, P4-VPOI and P4-VPDI, were synthesized from quaternization of poly(4-vinyl pyridine)...     

Binary TLBO algorithm assisted for designing plasmonic nano bi-pyramids-based absorption coefficient

A new efficient binary optimization method based on Teaching–Learning-Based Optimization (TLBO) algorithm is proposed to design an array of plasmonic nano bi-pyramids in order to achieve maximum absorption coefficient spectrum. In binary TLBO, a group of learners consisting of a matrix with binary entries controls the presence (‘1’) or the absence (‘0’) of nanoparticles in the array. Simulation results show that absorption coefficient strongly depends on the localized position of plasmonic nanoparticles. Non-periodic structures have more appropriate response in term of absorption coefficient. This approach is useful in optical applications such as solar cells and plasmonic nano antenna.     

Numerical analysis of the process chain for the production of PM components with integrated information storage

The powder metallurgical production offers a number of advantages compared to other manufacturing technologies. A few examples are the high level of material utilization, the production of net-shape parts and an extensive amount of alloying options. This paper describes the production process to integrate component relevant information in the component to increase its functional range. The analysis of the production process is done by means of numerical simulation. Therefore, the process chain, consisting of die pressing and sintering, is modeled based on a finite-element-analysis.