Study of the potential of alternative crops by integration of multisource data using a neuro‐fuzzy technique

This work proposes a neuro‐fuzzy method for suggesting alternative crop production over a region using integrated data obtained from land‐survey maps as well as satellite imagery. The methodology proposed here uses an artificial neural network (multilayer perceptron, MLP) to predict alternative crop production. For each pixel, the MLP takes vector input comprising elevation, rainfall and goodness values of different existing crops. The first two components of the aforementioned input, that is, elevation and rainfall, are determined from contour information of land‐survey maps. The other components, such as goodness values of different existing crops, are based on the productivity estimates of soil determined by fuzzyfication and expert opinion (on soil) along with production quality by the Normalized Difference Vegetation Index (NDVI) obtained from satellite imagery. The methodology attempts to ensure that the suggested crop will also be a high productivity crop for that region.     

Cellular uptake and cytotoxicity of silica nanotubes

"Template synthesized" silica nanotubes (SNTs) provide unique features such as end functionalization to control drug release, inner voids for loading biomolecules, and distinctive inner and outer surfaces that can be differentially functionalized for targeting and biocompatibility. Very limited information is available about their biological interactions. This work evaluates the influence of size and surface charge of SNTs on cellular toxicity and uptake. Results additionally indicate endocytosis to be one possible mechanism of internalization of SNTs.     

Interfacing solar PV power plant with rural distribution grid: challenges and possible solutions

In rural India and similar countries, the distribution grid is radial in nature where the power generation stations are located far away from the consumption points which makes the grid weak in nature at the site of consumption. Significant penetration of solar photovoltaic within the weak distribution network can cause voltage issues such as voltage rise and dip. A comprehensive simulation method as well as a simple mathematical modelling are developed. The study reveals that the voltage quality issue occurs not only due to the considerable penetration of photovoltaic (PV) but also due to the connected load and X/R ratio of the feeder. The proposed model describes a method to estimate the permissible PV penetration ratio for the distribution feeder. This helps in the (i) selection of overhead conductors to improve the X/R ratio, (ii) utilisation of the on load tap changing facility within the distribution transformer and (iii) connecting/disconnecting flexiloads for improving PV penetration.     

Cache Memory Design for Single Bit Architecture with Different SenseAmplifiers

Most modern microprocessors have one or two levels of on-chip caches to make things run faster, but this is not always the case. Most of the time, these caches are made of static random access memory cells. They take up a lot of space on the chip and use a lot of electricity. A lot of the time, low power is more important than several aspects. This is true for phones and tablets. Cache memory design for single bit architecture consists of six transistors static random access memory cell, a circuit of write driver, and sense amplifiers (such as voltage differential sense amplifier, current differential sense amplifier, charge transfer differential sense amplifier, voltage latch sense amplifier, and current latch sense amplifier, all of which are compared on different resistance values in terms of a number of transistors, delay in sensing and consumption of power. The conclusion arises that single bit six transistor static random access memory cell voltage differential sense amplifier architecture consumes 11.34 μW of power which shows that power is reduced up to 83%, 77.75% reduction in the case of the current differential sense amplifier, 39.62% in case of charge transfer differential sense amplifier and 50% in case of voltage latch sense amplifier when compared to existing latch sense amplifier architecture. Furthermore, power reduction techniques are applied over different blocks of cache memory architecture to optimize energy. The single-bit six transistors static random access memory cell with forced tack technique and voltage differential sense amplifier with dual sleep technique consumes 8.078 μW of power, i.e., reduce 28% more power that makes single bit six transistor static random access memory cell with forced tack technique and voltage differential sense amplifier with dual sleep technique more energy efficient.     

Improved delay‐dependent stabilization of time‐delay systems with actuator saturation

This paper addresses the controller synthesis problem of linear time‐delay systems subjected to saturating control. Delay‐dependent regional stabilization criteria are derived based on Lyapunov–Krasovskii approach by using both the polytopic or dead‐zone representation of the saturation function. The main contribution of the paper lies in developing less conservative convex criterion in terms of LMIs to obtain superior results. On the basis of the derived stabilization criterion, an optimization problem is defined to compute the stabilizing state feedback gains with an aim to maximize the stabilizing region while guaranteeing the asymptotic stability of the closed‐loop system. Considering three numerical examples, an assessment of the polytopic and dead‐zone nonlinearity approaches is made. Copyright © 2012 John Wiley & Sons, Ltd.     

Ionomeric modification of a metallocene‐based polyolefinic elastomer and its influence on the physicomechanical properties: Effects of the crystallinity and pendent chain length

A new class of ionomer was developed through the grafting of acrylic acid onto a metallocene‐based poly(ethylene octene) elastomer, followed by its neutralization with zinc acetate. The ionomeric product was characterized through Fourier transform infrared spectroscopy, small‐angle X‐ray scattering, and transmission electron microscopy studies. The effect of the crystallinity and pendent chain length on the ionomeric modification was also studied through the variation of the level and nature of comonomer, respectively. The impact of these ionomeric modifications on various physicomechanical properties was thoroughly investigated with differential scanning calorimetry and mechanical, dynamic mechanical, and thermogravimetric analysis, and the resulting properties were correlated with the structure of the modified elastomers. The ionomerization of the base elastomers caused a significant improvement in the mechanical and thermal properties compared to the corresponding pristine elastomer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Harmony search-based hybrid stable adaptive fuzzy tracking controllers for vision-based mobile robot navigation

In this paper the harmony search (HS) algorithm and Lyapunov theory are hybridized together to design a stable adaptive fuzzy tracking control strategy for vision-based navigation of autonomous mobile robots. The proposed variant of HS algorithm, with complete dynamic harmony memory (named here as DyHS algorithm), is utilized to design two self-adaptive fuzzy controllers, for $x$ -direction and $y$ -direction movements of a mobile robot. These fuzzy controllers are optimized, both in their structures and free parameters, such that they can guarantee desired stability and simultaneously they can provide satisfactory tracking performance for the vision-based navigation of mobile robots. In addition, the concurrent and preferential combinations of global-search capability, utilizing DyHS algorithm, and Lyapunov theory-based local search method, are employed simultaneously to provide a high degree of automation in the controller design process. The proposed schemes have been implemented in both simulation and real-life experiments. The results demonstrate the usefulness of the proposed design strategy and shows overall comparable performances, when compared with two other competing stochastic optimization algorithms, namely, genetic algorithm and particle swarm optimization.     

WPSS输入反馈时延的自适应分段补偿设计

广域电力系统稳定器(WPSS)是抑制电力系统区间模式振荡最有效的方法之一。WPSS以相量测量单元(PMU)量测的远方同步信号为反馈输入,在将其应用到工程实际时需要着重考虑远方信号的时延问题。从长期来看,时延通常会在一定范围内呈现一定的随机分布特性。文中设计了一种自适应分段时延补偿器,将时延分为若干个区间,对每一个区间设计时延补偿。时延补偿器根据在线量测得到的实际时延自适应地调整控制器的时延补偿区间,以达到最优补偿的目的。文中重点讨论了时延分段的方法以及时延补偿器自适应调整的规则。将提出的自适应分段时延补偿器在两区四机系统中实现,不同工况下的数值仿真结果表明了补偿器的有效性和鲁棒性。RTDS实验结果进一步表明所提方法可行且有效。该方法考虑了长时期内时延的变化,符合工程实际情况,适合于现场工程应用。     

A VARIABLE VOLTAGE AND FREQUENCY SCHEME TO OPTIMIZE THE EFFICIENCY OF A WIND-DRIVEN INDUCTION GENERATOR

ABSTRACT

The most recent approaches to harness energy from the wind utilizing induction generators has been made possible by advances in induction motor control using power electronic drives. The freedom in adjusting terminal voltage or current, and frequency al lows operation of the induction machine to fit any desired characteristic. The purpose of this paper is to propose a scheme using this technology to convert wind energy to electricity at maximum wind turbine power and induction generator efficiency. The Electromagnetic Transients Program (EMTP) is used to simulate the control of the induction generator. Simulation results show that this system operates as predicted in a stable fashion at the desired operating point.     

Microstructural relationship with fracture toughness of undoped and rare earths (Y, La) doped Al2O3–ZrO2 ceramic composites

Ceramic composites in undoped Al₂O₃–5 wt% ZrO₂ (AZ) and doped with rare earth elements Y, La separately and simultaneously were prepared by solid state sintering process. These composites were characterized for microstructural investigation and determination of phase formation to draw a possible relationship between these characterization results with the fracture toughness measured by single-edge precracked beam (SEPB) test method using three-point bend test. The fracture toughnesses of Y and Y + La doped AZ are found to be higher for samples sintered at 1700 °C for long soaking times, than that of La doped and undoped AZ composites. It is predicted from the XRD and EDS analyses that the phases of Zr_0.88Y_0.12O_1.94 and Zr_0.935Y_0.065O_1.968 are formed at or near the intergranular region and therefore the higher fracture toughness of Y and Y + La doped AZ composites compared to undoped AZ and La doped AZ composite for samples sintered at 1700 °C for long soaking times, is attributed to these intergranular phases.