SER and throughput analysis of space–time analog network coded relaying system over shadowed Rician fading channels

Wireless Networks - This research article presents an innovative approach based on analog network coding (ANC) in conjunction with space time block coding (STBC) which is termed as space time...     

Stability enhancement of induction generator–based series compensated wind power plants by alleviating subsynchronous torsional oscillations using BFOA‐optimal controller tuned STATCOM

In this paper, a STATCOM (static synchronous compensator) is used to encounter the potential SSR (subsynchronous resonance) observed by IG (Induction Generator) based series compensated wind farms. The basic controller used for STATCOM control is identical to that of the literature. An idea of a unique meta‐heuristic swarm‐based optimization technique called BFOA (bacterial foraging optimization algorithm) based optimal‐controller is introduced for optimal parameter selection of the basic controller used in the control scheme of the STATCOM. The investigation is carried out with 500 MW IG‐based wind farm exposed to three‐phase LLL‐G fault close to the PCC (point of common coupling) and implemented with MATLAB in both steady and transient states for the three different cases, namely, without STATCOM, with the basic STATCOM controller, and in the presence of the proposed BFOA‐optimal controller‐based STATCOM. In both the states, the observed eigenvalues of the test system, together with the time domain results of the generator rotor dynamics for three distinct cases, reveals the effectiveness of the suggested BFOA‐optimal controller tuned STATCOM in mitigating the potential SSR.     

Evaluation of the FEH Rainfall-Runoff Method for Catchments in the UK

The Flood Estimation Handbook, which was published in 1999, has substantially replaced the Flood Studies Report for design flood estimation in the UK. Although there are substantial differences between the handbook and the report, the philosophy of the rainfall-runoff method has been retained in the handbook. However, there are differences in the equations that have been used to estimate parameters of the rainfall-runoff method.
This paper provides a comprehensive evaluation of the performance of the Flood Estimation Handbook rainfall-runoff method for flood-frequency estimation, using data from eighty-eight catchments in the UK. The performance is evaluated by reference to the flood quantiles obtained from single-site frequency analysis, and comparison is made with the performance of the Flood Studies Report methodology. In general terms, the handbook over-estimates flood quantiles, with respect to (a) those estimated from observed records and (b) the report's quantiles. The paper explores the causes of these over-estimations and seeks linkages with particular catchment characteristics.     

On Plastic Deformation Behavior of Cryorolled AA8090 Alloy

AA8090 alloy was rolled up to 50 and 75 % reductions at both liquid nitrogen (LNR) and room temperatures (RTR). Both hardness and tensile behavior were evaluated on rolled samples. Optical microscope, TEM and EBSD were used for detailed microstructural examination of rolled samples. Williamson-Hall peak broadening analysis on X-ray diffraction data was made to evaluate crystallite size, lattice strain and dislocation density. An enhanced tensile strength was evidenced in LNR samples when compared to RTR samples without sacrificing ductility, which was ascribed to the higher density of dislocations in LNR samples than RTR samples. A large number of dislocation tangled regions along with ultrafine grain structure were evidenced through TEM and EBSD. Significant fraction of special boundaries in combination with increased fraction of texture components like S, Brass, Cu and Goss would be another reason for enhanced properties in LNR conditions than that of RTR. These components were observed to be strengthened with increased rolling reduction. Work hardening behavior clearly evidenced the variation in amount of work hardening and recovery phenomenon. It showed large variation in recovery in the case of 50 % reduction than that of 75 % reduction, which was attributed to significantly higher density of dislocations in 75 % rolled samples in RTR and LNR.     

Deformation and water loss from solvent filled microcapsules under compressive loads

Microcapsules filled with liquid solvents for CO₂ absorption can be easily deformed due to their elastic polymer shells. We present a combination of experiments and model predictions to demonstrate that modest compressive forces can lead to significant capsule deformation and performance issues for this enabling technology. Contrary to expectations based on Raoult's law, capsules containing aqueous carbonate solution were found to lose water to flows of humidified nitrogen in centimeter-scale packed beds. Water loss increased with gas velocity, suggesting compression was responsible for mass transfer, an interpretation supported by microscope images of deformed and broken capsules. A model for compression induced mass transfer under packed/fluidized bed operating conditions was developed and validated with the experimental data for a range of conditions (gas velocities, temperatures, humidities). Design criteria for future generations of microcapsules that will more effectively resist compression are evaluated.     

Silver nanoparticle films by flowing gas atmospheric pulsed laser deposition and application to surface-enhanced Raman spectroscopy

For the fast uptake into industrial applications, the further development of robust methods of nanomaterials, which are inexpensive and simultaneously technologically feasible, is one of the major key factors. A newly introduced atmospheric pulsed laser deposition method, based on a flowing gas approach, was used for plasmonic metal nanoparticle (NP) film of silver. Contrary to vacuum, in this method, the ambient air restricts expansion of the ablation plume within 1 to 3 mm above the target surface. These sets constrain on the formation of NP film close to the ablation spot. For deposition on a widely spaced surface, ablation material was entrained in a flow of argon, supplied at ~32 ms⁻¹, and effectively delivered to the substrate at ~20 ms⁻¹. The films produced were crystalline and particulate in nature, showing spectral plasmonic feature of surface plasmon resonance in the visible region. The film was directly tested in surface-enhanced Raman spectroscopy for chemical detection of crystal violet; the film with large particulates and aggregated crystallites was well-performed, showing enhanced Raman signals and detection sensitivity. Certainly, flowing gas atmospheric pulsed laser deposition seems a fast alternative to vacuum-pulsed laser deposition but needs further investigations to bring it in the industry for applications in sensor, catalysis, solar cell, and coating technology.     

On the application of remote sensing towards the estimation of cultivated land lost to urbanization

In this research work, a 40-km² SPOT-5 High-Resolution Imagery (HRI) of the Warsak locality in district Peshawar, Pakistan, was utilized to approximate the quantity of cultivated land lost to urbanization, due to the construction of new homes and buildings. The imagery from a period of 2005 to 2015 for wheat crop was taken, specifically during the months of March and June when the crop is rich green and golden ripe respectively. eCognition ® program’s Object-Oriented Classification Method (OOCM) was employed for recognition of land versus buildings. Nearest Neighbour (NN), Support Vector Machine (SVM), Decision Trees (DT) and Random Forests (RF) were utilized for the classification process. The results demonstrated that the urbanized area had increased by approximately 28 per cent in the area considered. Moreover, the efficacy of the proposed method is depicted by an accuracy of 97.9 per cent and a Kappa Statistics of 0.975 for the SVM classifier.