Gain enhancement of slot antenna using zero‐index metamaterial superstrate

This article presents a technique to enhance the broadside gain of a CPW fed slot antenna using a single layer metamaterial (MTM) superstrate. A finite array of 3 3 ring unit cell has been designed on both sides of a dielectric substrate to form the MTM superstrate. The gain enhancement is obtained using the zero‐index property of the metamaterial. The broadside gain enhancement for the proposed antenna is 7.4 dB more in comparison to that of the reference slot antenna. The proposed MTM superstrate loaded antenna provides a minimum overall thickness in the context of using ZIM superstrate for gain enhancement of antennas reported in earlier literatures. The overall thickness of the MTM loaded antenna is 0.13λ₀, where λ₀ is the free‐space wavelength at the resonance frequency of the antenna. Also, a high efficiency of about 93.2% is obtained in this case. The loading of the MTM superstrate produces a minimal effect on the cross polarization performance of the proposed slot antenna.     

Miniaturization of a patch antenna using circular reactive impedance substrate

In this article, to construct a reactive impedance substrate, unit ring is designed and proposed with radial and concentric mode analysis. A cylindrical substrate backed with a PEC plane and circular metallic elements on the top is used for achieving reactive surface impedance behavior. In this aspect, three unit rings structure with different ring elements are designed and simulated to realize the reflection phase characteristics. Afterwards, a probe‐fed circular patch antenna is miniaturized by stacking the three‐ring circular reactive impedance surface. The fundamental resonance frequency of the proposed antenna is reduced by about 30% with an improvement in impedance bandwidth by 121.6%. An improved front‐to‐back ratio as well as an acceptable co‐pol and cross‐pol isolation is exhibited in both E‐plane and H‐plane at the resonance frequency. In addition of miniaturization, dual band behavior has also been observed in the proposed design. Both resonance phenomena have been explained by circuit model representation and surface current distribution analysis. Improved radiation efficiency at 81.5% has been measured for the proposed antenna configuration.     

ADAPTIVE OPTIMIZATION OF CONTINUOUS BIOREACTOR USING NEURAL NETWORK MODEL

An adaptive optimization algorithm using backpropogation neural network model for dynamic identification is developed. The algorithm is applied to maximize the cellular productivity of a continuous culture of baker's yeast. The robustness of the algorithm is demonstrated in determining and maintaining the optimal dilution rate of the continuous bioreactor in presence of disturbances in environmental conditions and microbial culture characteristics. The simulation results show that a significant reduction in time required to reach optimal operating levels can be achieved using neural network model compared with the traditional dynamic linear input-output model. The extension of the algorithm for multivariable adaptive optimization of continuous bioreactor is briefly discussed.     

The bivariate generalized linear failure rate distribution and its multivariate extension

The two-parameter linear failure rate distribution has been used quite successfully to analyze lifetime data. Recently, a new three-parameter distribution, known as the generalized linear failure rate distribution, has been introduced by exponentiating the linear failure rate distribution. The generalized linear failure rate distribution is a very flexible lifetime distribution, and the probability density function of the generalized linear failure rate distribution can take different shapes. Its hazard function also can be increasing, decreasing and bathtub shaped. The main aim of this paper is to introduce a bivariate generalized linear failure rate distribution, whose marginals are generalized linear failure rate distributions. It is obtained using the same approach as was adopted to obtain the Marshall-Olkin bivariate exponential distribution. Different properties of this new distribution are established. The bivariate generalized linear failure rate distribution has five parameters and the maximum likelihood estimators are obtained using the EM algorithm. A data set is analyzed for illustrative purposes. Finally, some generalizations to the multivariate case are proposed.     

One dimensional nanostructured materials

The quest for materials with molecular scale properties that can satisfy the demands of the 21st century has led to the development of one dimensional nanostructures, ODNS. Nearly, every class of traditional material has an ODNS counterpart. ODNS has a profound impact in nanoelectronics, nanodevices and systems, nanocomposite materials, alternative energy resources and national security. The interface of nanoscience and technology with biological and therapeutic sciences is expected to radically improve the ability to provide efficient treatments in otherwise impossible situations. Ironically, the huge investment in the past few years across the globe is yet to bring the real benefit of nanotechnology in day to day life. While scientists and engineers are working towards this goal, concerns about the possible harmful effects of the high aspect ratio materials are increasing every day. Following is an effort to assimilate most of the aforementioned aspects including the entire gamut of ODNS, i.e., elements, ceramics, polymers and composites, with a brief discussion on CNT and toxicology. The focus of this article is mainly on the science behind the synthesis and properties of the ODNS rather than the device fabrication. However, a few challenges in the field of device fabrication are mentioned in appropriate contexts. Possible mechanisms of the ODNS evolution from various methods, such as vapor liquid solid (VLS), template based and electrochemically induced growth, have been discussed in detail. Electron microscopy analysis has received special focus in determining the unique structural features. The article concludes by discussing current research related to environment and toxicology effects and current challenges in this rapidly evolving field.     

Methionine-pyrene hybrid based fluorescent probe for trace level detection and estimation of Hg(II) in aqueous environmental samples: experimental and computational studies

A new fluorescent, Hg(2+) selective chemosensor, 4-methylsulfanyl-2-[(pyren-4-ylmethylene)-amino] butyric acid methyl ester (L, MP) was synthesized by blending methionine with pyrene. It was well characterized by different analytical techniques, viz. (1)H NMR, (13)C NMR, QTOF mass spectra, elemental analysis, FTIR and UV-vis spectroscopy. The reaction of this ligand with Hg(2+) was studied by steady state and time-resolved fluorescence spectroscopy. The Hg(2+) complexation process was confirmed by comparing FTIR, UV-vis, thermal, QTOF mass spectra and (1)H NMR data of the product with that of the free ligand values. The composition (Hg(2+):L=1:1) of the Hg(2+) complex in solution was evaluated by fluorescence titration method. Based on the chelation assisted fluorescence quenching, a highly sensitive spectrofluorometric method was developed for the determination of trace amounts of Hg(2+) in water. The ligand had an excitation and emission maxima at 360 nm and 455 nm, respectively. The fluorescence life times of the ligand and its Hg(2+) complex were 1.54 ns and 0.72 ns respectively. The binding constant of the ligand, L with Hg(2+) was calculated using Benesi-Hildebrand equation and was found to be 7.5630×10(4). The linear range of the method was from 0 to 16 μg L(-1) with a detection limit of 0.056 μg L(-1) for Hg(2+). The quantum yields of the ligand and its Hg(2+) complex were found to be 0.1206 and 0.0757 respectively. Both the ligand and its Hg(2+) complex have been studied computationally (Ab-initio, Hartree Fock method) to get their optimized structure and other related physical parameters, including bond lengths, bond angles, dipole moments, orbital interactions etc. The binding sites of the ligand to the Hg(2+) ion as obtained from the theoretical calculations were well supported by (1)H NMR titration. The interference of foreign ions was negligible. This method has been successfully applied to the determination of mercury(II) in industrial waste water.     

Test Planning in Digital Microfluidic Biochips Using Efficient Eulerization Techniques

Digital microfluidic technology is now being extensively used for implementing a lab-on-a-chip. Microfluidic biochips are often used for safety-critical applications, clinical diagnosis, and for genome analysis. Thus, devising effective and faster testing methodologies to warrant correct operations of these devices after manufacture and during bioassay operations, is very much needed. In this paper, we propose an Euler tour based technique to obtain the route plan of a test droplet for the purpose of structural testing of biochips. The method is applicable to various digital microfluidic biochip architectures, e.g., fully reconfigurable arrays, application specific biochips, pin-constrained irregular geometry biochips, and to defect-tolerant biochips. We show that in general, the optimal Eulerization and subsequent determination of an Euler tour in the graph model of a biochip can be abstracted in terms of the classical Chinese postman problem. The Euler tour can be identified by running the classical Hierholzer’s algorithm, which relies on a simple cycle decomposition and splicing method. This improved Eulerization technique leads to an efficient test plan for the chip. This can also be used in phase-based test planning that yields savings in testing time. The method provides a unified approach towards structural testing and can be easily adopted to design a droplet routing procedure for functional testing of digital microfluidic biochips.     

Estimation of parameters of two-dimensional random amplitude chirp signal in additive noise

Multidimensional Systems and Signal Processing - In this paper, we consider a two-dimensional random amplitude chirp signal model. It is assumed that the additive error is independent and...     

Assessment of Water Quality around Surface Coal Mines using Principal Component Analysis and Fuzzy Reasoning Techniques

Water samples collected from surface coal mine sites, adjacent rivers, and nearby tube wells were analyzed for pH, selected contaminant concentrations, electrical conductivity, total dissolved solids, total suspended solids, and total hardness. Statistical analysis of the data showed that most of the parameters (variables) were correlated with each other, having a correlation coefficient between 0.29 and 0.99. Hence, variability of output parameter, in this case, water quality around mine sites, cannot be explained explicitly by any single input parameter. Principal component analysis was used to evaluate the orthogonal and independent components of the original data sets. The first principal component and pH were used to compare water quality around the mine sites using fuzzy reasoning techniques based on Mamdani’s principle. Finally, a prediction map of water quality was prepared for the entire study area. Although the contaminants of concern will vary from site to site, this basic approach should be useful in assessing water quality at other locations where funds or site access limit ones ability to sample more intensely.     

No-Cloning and No-Deleting Theorems through the Existence of Incomparable States Under LOCC

No-cloning and No-deleting theorems are verified with the constraint on local state transformations via the existence of incomparable states. Assuming the existence of exact cloning or deleting operation defined on a minimum number of two arbitrary states, an incomparable pair of states of the joint system between two parties can be made to compare under deterministic LOCC. We have restricted our proof with the assumption that the machine states of the cloning or deleting operations do not keep any information about the input states. We use the same setting to establish the no-cloning and no-deleting theorems via incomparability that supports the reciprocity of the two operations in their operational senses. The work associates the impossibility of operations with the evolution of an entangled system by LOCC.