Shifting of research trends in islanding detection method - a comprehensive survey

The augmentation in electricity demand, power system privatization as well as efficacy of renewable resources has paved the way for power system companies and researchers to exploit the field of grid connected distributed generation (DG) and its issues, islanding being a dominant one. Several research works have been conducted to mitigate the issues of islanding detection (ID). In context of this, the paper gives a comprehensive review of islanding issues, standard test systems, criteria and shifting of research trends in islanding detection methods (IDMs). The significant contributions pertain to categorization of IDMs, evaluation of non-detection zone (NDZ) for each test system, disquisition on evolution and advancement of IDMs and its comparisons based on criteria such as NDZ, run on time, nuisance tripping percentage, applicability in multi DG system and implementation cost to draw out the strength and shortcomings of individual methods that will come to aid to the companies or researchers for establishing the applicability and appropriateness of such method for their concerned domain.     

Preparation and properties of styrene–butadiene rubber based nanocomposites: The influence of the structural and processing parameters

Rubber‐based nanocomposites were prepared with octadecyl amine modified sodium montmorillonite clay and styrene–butadiene rubber with different styrene contents (15, 23, and 40%). The solvent used to prepare the nanocomposites, the cure conditions, and the cure system were also varied to determine their effect on the properties of the nanocomposites. All the composites were characterized with X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The XRD studies revealed exfoliation for the modified clay–rubber composites. The TEM photomicrographs showed a uniform distribution of the modified clay in the rubber matrix. The thickness of the particles in the exfoliated composites was around 10–15 nm. Although the FTIR study of the unmodified and modified clays showed extra peaks due to the intercalation of the amine chains into the gallery, the spectra for the rubber–clay nanocomposites were almost the same because of the presence of a very small amount of clay in the rubber matrix. All the modified clay–rubber nanocomposites displayed improved mechanical strength. The styrene content of the rubber had a pronounced effect on the properties of the nanocomposites. With increasing styrene content, the improvement in the properties was greater. Dicumyl peroxide and sulfur cure systems displayed similar strength, but higher elongation and slightly lower modulus values were obtained with the sulfur cure system. The curing of the samples at four different durations at 160°C showed that the cure time affected the properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 698–709, 2004     

Effect of an asymmetrical V-notch on the load carrying capacity of eccentrically loaded columns

In this paper theoretical and experimental investigations have been carried out to determine the effect of an asymmetrical V-shaped notch on the load carrying capacity of eccentrically loaded columns. The depth of the notch was kept constant whereas the notch angle, notch root radius; eccentricity of loading and length of the column was varied. It has been concluded that an asymmetrically placed V-notch decreases the load carrying capacity of the column. The load carrying capacity is not affected appreciably upto a notch angle of approx. 90°, but beyond 90° it increases. The load carrying capacity of the column also increases as the notch root radius increases but it decreases as the eccentricity of load and slenderness ratio increase.     

Genetic neural-based modeling of AC resistance of heating coil used for high-frequency inverter-fed induction cooker

The present paper deals with modeling of AC resistance of twisted litz wires used for high-frequency inverter-fed induction cooker. Several traditional approaches are available, most of which have concentrated in deriving the analytical relationships between the AC resistances with the parameters of the wire. However, it is very difficult to get the exact relationship, due to several reasons. An attempt is made in this paper to model the AC resistance using a three-layered feed-forward Neural Network. For this purpose, four inputs (wire type, number of strand, number of spiral turn and operating frequency) and one output as AC resistance have been considered. Since the performance of Neural Network alone might not be optimal; it is optimized using a binary-coded Genetic Algorithm. Performances of the proposed approach were compared with the method of AC resistance computation proposed by Ferreira. Genetic-neural system has given a very close accuracy, and the computational complexity was found to be very low. Thus, it is suitable for online implementations.     

The incorporation of mono- and bi-functionalized multiwall carbon nanotubes in organic photovoltaic cells

We have successfully prepared mono- and bi-functionalized multiwall carbon nanotubes (MWCNT) with thiophene, amine and thiophene-amine groups. The dispersion of nanotubes has been enhanced and stable optimized dispersions in organic solvents were obtained. These functionalized nanotubes have been successfully incorporated into bulk heterojunction (BHJ) organic photovoltaic (OPV) cells with a poly (3-hexyl thiophene) (P3HT) and [6, 6]-phenyl-C(61)-butyric acid methyl ester (PCBM) photoactive blended layer. The incorporation of MWCNT with different functional groups, in the active layer, results in different cell performance with respect to a reference cell. A maximum power conversion efficiency of 2.5% is achieved with the inclusion of thiophene functionalized nanotubes. This improvement in the device performance is attributed to an extension of the exciton dissociation volume and charge transport properties through the nanotube percolation network in P3HT/CNT, PCBM/CNT or both phases. This is believed to be due to more efficient dispersion of the functionalized nanotubes within the photoactive composite layer.     

A simple technique for installing strain gauges on cylindrical surfaces

In this paper a simple technique for the installation of strain gauges on circular and conical cylindrical surfaces has been described. This technique may be adopted in an experimental stress analysis laboratory where sophisticated equipment is not available.     

Computer aided analysis of strain rosette data

In this paper a computer program has been developed for analysing the strain gauge rosettes by considering the transverse sensitivity of all gauges. The program is capable of calculating principal strains, maximum shear strain, principal stresses, maximum shear stress and principal directions from the data obtained by using strain gauge rosettes of various configurations. The gauge factor and transverse sensitivity of all gauges in the rosette must be the same.     

Morphology study of rubber based nanocomposites by transmission electron microscopy and atomic force microscopy

Rubber based nanocomposites were prepared using octadecyl amine modified Na-montmorillonite clay (OC) and Styrene Butadiene Rubber (SBR) having styrene content of 15, 23 and 40% respectively and Acrylonitrile Butadiene Rubber (NBR) having acrylonitrile content of 19, 34 and 50% respectively. The morphology of the nanocomposites was investigated using Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM) and X-ray Diffraction Technique (XRD). The TEM photographs of the unmodified clay loaded SBR nanocomposite showed agglomeration, while the modified clay loaded SBRs of all the grades revealed complete exfoliation. The NBRs, on the other hand, gave unexfoliated and intercalated clay structures both with the unmodified and the modified clays, except in the case of NBR having 19% of acrylonitrile and 4% of the unmodified clay. The AFM data were in good accord with the TEM results. The particle dimensions were within the range of 10–20 nm in the case of SBR sample having 4 parts of the modified clay. NBRs having 34 and 50% acrylonitrile contents and 4 parts of OC showed clay particles ranging from 50–70 nm and 70–100 nm respectively. On comparison of the rubbers having different nature and contents of functional groups and filler loadings, significant effect on the morphology of the composite was observed. The nature of solvent used to prepare the nanocomposites also affected the morphology. XRD data further corroborated the facts in all the above cases.     

XOR transform with actin quantum automata for better security against cryptanalysis

XOR is a basic cryptographic transform, used as a one way function inside of complex cryptosystems. In this paper we propose first of a kind design of the XOR transform with a universal logic designing paradigm. The system offers enhanced security to the transform by propagating randomly generated information along with the XOR output over the unsecured channel. This additional security is a inherent attribute of the actin automata and is exploited in this paper. The system can be enacted on a Partitioned one-Dimensional Quantum Cellular Automata. A simulation of the proposed system is illustrated with Simulink tool in MATLAB. Based on the work done by Adamatzky et al. we observe that the actin automata is capable of operating on quantum input bits and can generate appropriate results when required. In this paper, the actin automata is simulated with classical bits instead of quantum bits for designing the transform. We have also tried to establish the proposed system by means of low power consumption verified with NI Multisim and comparison with cryptographic complexity with traditional XOR transform. Additionally, we have analyzed the system for enhanced cryptanalytic complexity against various attacks.

     

Analysis of a three-phase to seven-phase transformer under unbalanced input

Microsystem Technologies - In the recent past, multiphase power generation, power transmission, and multiphase drive system are the main focus of research due to their several advantages over...