Hybrid plasmonic label-free multi-analyte refractive index sensor

We propose a label-free refractive index sensor based on hybrid plasmonic resonator which consists of silver split-ring resonator and photonic waveguide. The finite difference time domain evaluation of the design exhibit strong field confinement at the center of the ring and introduces tunable and sensitive notches in the transmission spectrum. The planar tunable architecture which performs well over the range of micro fluid detection, holds the promise of developing multi-analyte label-free biosensors and compactness towards a complete on-chip integrated sensing system. The performance of the proposed refractive index sensor is evaluated by placing different analytes such as saline water and ethanol at the center of the hybrid plasmonic ring which exhibits sensitivity of 847.50 nm.RIU-1 with a figure of merit of 563.25 RIU-1.     

An Effective Traceback Network Attack Procedure for Source Address Verification

Wireless Personal Communications - The Internet is being extensively used in various fields to serve billions of users, which leads to the number of network security issues. Here, Internet Protocol...     

Effect of various water immersions on mechanical properties of roselle fiber–vinyl ester composites

In the present communication, the effect of water absorptions on mechanical properties of roselle fiber reinforced vinyl ester composites prepared by wet hand lay‐up method was studied. Water absorption tests were conducted by immersing composite specimens into three different water environments, namely distilled water, ground water, and sea water, which were at room temperature, for a period of 10 days. The water absorption behavior of composite was found to follow a non‐Fickian behavior. The maximum water absorption percent and diffusion coefficient were determined from the obtained water absorption curves. The scanning electron microscopy was used for the fractographic studies on the fractured surface of composite. The results show that composites exposed to sea water environment absorb more water absorption percent than that of other water environments. It was observed that the water absorption percent increased with increasing fiber loading. Mechanical properties of dry composite specimens were compared with wet composite specimens. Mechanical properties were found to decrease with an increasing percentage of water uptakes. POLYM. COMPOS., 36:1638–1646, 2015. © 2014 Society of Plastics Engineers     

Novel soft-switching DC-DC converter with full ZVS-range andreduced filter requirement. I. Regulated-output applications

A novel soft-switching topology for DC-DC converters is proposed. It is well suited for applications in the range of a few hundred watts to a few kilowatts. It is essentially a hybrid combination of an uncontrolled half-bridge section and a phase-shift controlled full-bridge section, realized with just four switches. The main features of the proposed topology are zero-voltage-switching down to no-load without serious conduction loss penalty, constant frequency operation and, near-ideal filter waveforms. The improved filter waveforms result in significant savings in the input and output filter requirement, resulting in high power-density. The new topology requires two transformers and two DC-bypass capacitors. The combined VA rating of the two transformers is more than that of the single transformer of conventional full-bridge converters, for variable-input applications. In Part I of the paper, the converter operation is analyzed for typical switch-mode power supply applications, where the input voltage varies widely but the output voltage is fixed and is well regulated. Experimental results obtained from a 100 W/200 kHz proof-of-concept prototype confirm the superior features of the proposed hybrid configuration     

A high-performance, integrated magnetics scheme for buck-cascaded push-pull converter

This letter proposes a new integrated magnetics scheme for the buck cascaded current-fed push-pull converter. While integrating the transformer and inductor into a common structure, the proposed scheme also alters the operating characteristics of the basic converter. This leads to several advantages such as, continuous output current, zero voltage switching (ZVS), and zero current switching (ZCS) for the switches of the push-pull stage, and reduced conduction losses. The principle of operation of the proposed scheme is analyzed using the gyrator-capacitor model. Experimental results from a 12 V/5 A proof-of-concept prototype are presented demonstrating the advantages of the proposed scheme.     

Active input-voltage and load-current sharing in input-series and output-parallel connected modular DC-DC converters using dynamic input-voltage reference scheme

This paper explores a new configuration for modular DC/DC converters, namely, series connection at the input, and parallel connection at the output, such that the converters share the input voltage and load current equally. This is an important step toward realizing a truly modular power system architecture, where low-power, low-voltage, building block modules can be connected in any series/parallel combination at input or at output, to realize any given system specifications. A three-loop control scheme, consisting of a common output voltage loop, individual inner current loops, and individual input voltage loops, is proposed to achieve input voltage and load current sharing. The output voltage loop provides the basic reference for inner current loops, which is modified by the respective input voltage loops. The average of converter input voltages, which is dynamically varying, is chosen as the reference for input voltage loops. This choice of reference eliminates interaction among different control loops. The input-series and output-parallel (ISOP) configuration is analyzed using the incremental negative resistance model of DC/DC converters. Based on the analysis, design methods for input voltage controller are developed. Analysis and proposed design methods are verified through simulation, and experimentally, on an ISOP system consisting of two forward converters.     

Walsh Spectrum Measurement in Natural, Dyadic, and Sequency Ordering

Walsh spectra may have natural, dyadic, or sequency ordering. This paper describes an improved processor design to provide spectra in any selected ordering. The incoming data are stored either directly or in a permuted sequence, and then are followed by a fast Walsh-Hadamard transform. For sequency ordering, the permutation operation is that of a Gray-to- binary code conversion, followed by bit reversal. For dyadic ordering, the operation is only a bit reversal. First a Hadamard processor that uses long shift registers is described. It is adapted to yield coefficients in either of the other two orderings by way of the permuting module (PM).     

An Energy Efficient Clustered Gravitational and Fuzzy Based Routing Algorithm in WSNs

Wireless Personal Communications - Wireless sensor networks consist of many tiny sensor nodes which are deployed in various geographical locations for sensing the normal spectacles and also to...