Novel CPG algorithm for tracking fast sudden changes based on tangent rule

ABSTRACT

This paper proposes a novel tracking method to deal with fast changes of solar irradiation and power limit change in order to increase tracking efficiency. This goal is achieved by estimating (i) next operating mode and (ii) next step point with the use of tangent rule in triangle. After every fast response to sudden changes, accurate response phase starts in order to track desired power in each operating mode by adaptive step size. Drift problem in defining next operating mode is eliminated in proposed method by estimating next operating mode, and settling time is decreased to about 25 percent of settling time of other methods by estimating next step point. Simulation and experimental results show the performance of proposed method.     

Introducing an Efficient Statistical Model for Automatic Modulation Classification

Journal of Signal Processing Systems - Nowadays, Automatic Modulation Classification (AMC) plays an important role in many applications of cooperative and non-cooperative communication such as...     

Single Molecule with Dual Function on Nanogold: Biofunctionalized Construct for In Vivo Photoacoustic Imaging and SERS Biosensing

Multimodal imaging provides complimentary information that is advantageous in studying both cellular and molecular mechanisms in vivo, which has tremendous potential in pre‐clinical research and clinical translational imaging. It is desirable to design probes for multimodal imaging that can be administered minimally but provides multifaceted information. Herein, we demonstrate the complementary dual functional ability of a nanoconstruct for molecular imaging in both photoacoustic (PA) and surface‐enhanced Raman scattering (SERS) biosensing simultaneously in tandem. To realize this, a group of NIR active organic molecules are designed and synthesized that possess both SERS and PA activity. Nanoconstructs realized by anchoring such molecules onto gold nanoparticles are demonstrated for targeting cancer biomarkers in vivo while providing complimentary information about biodistribution and targeting efficiency. In future, such nanoconstructs could play a major role in identifying surgical margins and also for disease monitoring in translational medicine.     

Integrating IPsec within OpenFlow Architecture for Secure Group Communication

Network securityprotocolssuch as IPsechave been used for many years to ensure robust end-to-end communication and are impor-tant in the context of SDN.Despite the widespread installation of IPsec to date,per-packet protection offered by the protocol isnot very compatible with OpenFlow and flow-like behavior.OpenFlow architecture cannot aggregate IPsec-ESP flows in transportmode or tunnel mode because layer-3 information is encrypted and therefore unreadable.In this paper,we propose using the Secu-rity Parameter Index(SPI)of IPsec within the OpenFlow architecture to identify and direct IPsec flows.Thisenables IPsec to con-form to the packet-based behavior of OpenFlow architecture.In addition,by distinguishing between IPsec flows,the architectureis particularly suited to secure group communication.     

High Productive Ethylene Trimerization Catalyst Based on CrCl<Subscript>3</Subscript>/SNS Ligands

Abstract  

Methylaluminoxane (MAO)-activated chromium (III) complexes of tridentate SNS ligands of the form (RSCH₂–CH₂)₂NH (R = alkyl, aryl) have been prepared and tested for the trimerization of ethylene to 1-hexene. The effect of ethylene pressure, Al/Cr ratio and S donor substitution on 1-C6 selectivity and productivity has been examined. It is shown that when the substitution on S is pentyl group it will lead to the highest productivity, 174200 g 1-C6/g Cr h, due to the synergistic effect of this group.     

Effect of cellulose acetate/cellulose triacetate ratio on reverse osmosis blend membrane performance

Surface functionalization and modification including the grafting process are effective approaches to improve and enhance the reverse osmosis (RO) membrane performance. This work is aimed to synthesize grafted/crosslinked cellulose acetate (CA)/cellulose triacetate (CTA) blend RO membranes using N-isopropylacrylamide (N-IPAAm) as a monomer and N,N-methylene bisacrylamide (MBAAm) as a crosslinker. The morphology of these membranes was analyzed by scanning electron microscopy and their surface roughness was characterized by atomic force microscopy. The performance of these membranes was evaluated through measuring two major parameters of salt rejection and water flux using RO unit at variable operating pressures. It was noted that the surface average roughness obviously decreased from 148 nm for the pure CA/CTA blend membrane with 2.5% CTA to 110 nm and 87 nm for the grafted N-IPAAm and grafted/crosslinked N-IPAAM/MBAAm/CA/CTA-RO membranes, respectively. Moreover, the contact angle decreased from 51.98° to 47.6° and 43.8° after the grafting and crosslinking process. The salt rejection of the grafted CA/CTA-RO membrane by 0.1% N-IPAAm produced the highest value of 98.12% and the water flux was 3.29 L/m²h at 10 bar.     

Influence of monovalent cations and CuO nanoparticles on X-nanozeolite in uranium anionic species separation from contaminated drinking water

The main purpose of this work was the modification of NaX nanozeolite using copper oxide nanoparticles and various monovalent cations such as K~+, Cs~+, and Ag~+in order to make the negatively charged zeolite surface accessible for anionic forms of uranium which are the most dominant species of uranium in the contaminated radioactive waters at natural p H. Various methods such as the X-ray fluorescence(XRF), X-ray powder diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FT-IR), and atomic absorption spectroscopy(AAS) were used to characterize the final synthesized absorbents. Batch technique was used to study the adsorption behavior of uranium ions from polluted drinking water by Na X nanozeolite and its modified forms. In order to better understand the performance of them, the results were compared with those that were obtained for synthesizing bulk NaX zeolite and Na-form of clinoptilolite natural zeolite. Preliminary results indicated that uranium sorption increased as the loading level of CuO nanoparticles on NaX nanozeolite increased from 2.1 wt% to 11.2 wt%. In addition,from the obtained data, an increase in uranium removal efficiency resulted as charge/ionic radius ratio of exchanged cation decreased. Also, the effect of contact time, solid–liquid ratio, initial concentration and temperature on the adsorption process was studied. It is worth mentioning that, in this study, the sorption of uranium was performed under natural conditions of pH and the presence of competing cations and anions which are available in drinking waters.     

Fabricating and robust artificial neural network modeling nanoscale polyurethane fiber using electrospinning method

With regard to the fact that currently there is no comprehensive method to predict diameter of polyurethane/solvent fiber from electrospinning, in this study, diameter prediction of polyurethane/solvent fiber was conducted using neural networks and an error of 166 nm was observed. This error shows that artificial neural networks (ANNs) can predict diameter of electrospinning polyurethane fibers well. Then, considering weak repeatability nature of electrospinning in fabricating fibers with desired diameter, least mean square is used to improve stability of neural network model that shows an error of 113 nm, which represented better results compared to common ANN. To investigate the effect of each one of parameters affecting fiber diameter, sensitivity analysis was conducted. Along with this predicting model, sensitivity analysis can be used to reduce parameters space before conducting future studies. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45116.     

A numerical study on heat transfer enhancement and design of a heat exchanger with porous media in continuous hydrothermal flow synthesis system

The aim of this study is to use a new configuration of porous media in a heat exchanger in continuous hydrothermal flow synthesis (CHFS) system to enhance the heat transfer and minimize the required length of the heat exchanger.For this purpose,numerous numerical simulations are performed to investigate performance of the system with porons media.First,the numerical simulation for the heat exchanger in CHFS system is validated by experimental data.Then,porous media is added to the system and six different thicknesses for the porous media are examined to obtain the optimum thickness,based on the minimum required length of the heat exchanger.Finally,by changing the flow rate and inlet temperature of the product as well as the cooling water flow rate,the minimum required length of the heat exchanger with porous media for various inlet conditions is assessed.The investigations indicate that using porous media with the proper thickness in the heat exchanger increases the cooling rate of the product by almost 40％and reduces the required length of the heat exchanger by approximately 35％.The results also illustrate that the most proper thickness of the porous media is approximately equal to 90％ of the product tube's thickness.Results of this study lead to design a porous heat exchanger in CHFS system for various inlet conditions.