Structure and magnetic properties of Cd doped copper ferrite

This report presents the synthesis of copper cadmium ferrite (Cu_1−xCd_xFe₂O_4,x = 0.3, 0.4, 0.5, 0.6 and 0.7) by citrate precursor method and its subsequent characterization by using X-ray diffraction (XRD), electron diffraction spectroscopy (EDS) and vibrating sample magnetometer (VSM) techniques. XRD results confirm the single cubic spinel phase formation with the particle size of 40 nm, which decreased up to 20 nm with increases in Cd content, while the lattice parameter increased with increase in Cd content. By using VSM technique, a significant change in the magnetic properties was observed in CuFe₂O₄ system with Cd doping. It is seen that magnetic field H_C and remnant magnetization M_R increases with increasing concentration up to x = 0.6 except for x = 0.4 and 0.7.     

Plan recognition in exploratory domains

This paper describes a challenging plan recognition problem that arises in environments in which agents engage widely in exploratory behavior, and presents new algorithms for effective plan recognition in such settings. In exploratory domains, agents? actions map onto logs of behavior that include switching between activities, extraneous actions, and mistakes. Flexible pedagogical software, such as the application considered in this paper for statistics education, is a paradigmatic example of such domains, but many other settings exhibit similar characteristics. The paper establishes the task of plan recognition in exploratory domains to be NP-hard and compares several approaches for recognizing plans in these domains, including new heuristic methods that vary the extent to which they employ backtracking, as well as a reduction to constraint-satisfaction problems. The algorithms were empirically evaluated on people?s interaction with flexible, open-ended statistics education software used in schools. Data was collected from adults using the software in a lab setting as well as middle school students using the software in the classroom. The constraint satisfaction approaches were complete, but were an order of magnitude slower than the heuristic approaches. In addition, the heuristic approaches were able to perform within 4% of the constraint satisfaction approaches on student data from the classroom, which reflects the intended user population of the software. These results demonstrate that the heuristic approaches offer a good balance between performance and computation time when recognizing people?s activities in the pedagogical domain of interest.     

Symbolic noise modeling,analysis and optimization of a CMOS input buffer

This paper presents the symbolic noise modeling, analysis and optimization of an Input Buffer designed using RFCMOS technology, intended to be used in a high speed Track and Hold Amplifier (THA). The symbolic noise modeling and analysis are carried out by modeling each RF-MOSFET present in the Input Buffer by its nullor equivalent noise model. This helps in better understanding the noise involvement with the circuit and its optimization. All the extrinsic and intrinsic components associated with the RF-MOSFET used for the symbolic noise analysis are obtained using parameter extraction technique. The parameter extraction and symbolic noise analysis are done using MATLAB. The results obtained through MATLAB simulation are in good agreement with the results obtained from SPICE.     

The role of substrate temperature on the properties of nanocrystalline Mo doped ZnO thin films by spray pyrolysis

Transparent conducting molybdenum (2 at.%) doped zinc oxide (MZO) films were prepared with various substrate temperatures by spray pyrolysis technique on glass substrates. The effect of substrate temperature on the structural, surface morphological, electrical, optical and photoluminescence properties of these films were studied. The X-ray diffraction analysis revealed that the films are polycrystalline in nature having a wurtzite structure with a preferred grain orientation in the (0 0 2) direction. The average crystallite size of the films increases from 17 nm to 28 nm with the increase of substrate temperature from 573 K to 623 K, thereafter it slightly decreases with further increase of substrate temperature to 723 K. Analysis of structural parameters indicates minimum strain and stress values for films deposited at a substrate temperature of 673 K. From atomic force microscopy (AFM) analysis, it is found that rms roughness of the films deposited at 623 K is a minimum, indicating better optical quality. The scanning electron microscopy (SEM) measurements showed that the surface morphology of the films changes with substrate temperature. Optical parameters such as optical transmittance, reflectance, refractive index, extinction coefficient, dielectric constant and optical band gap have been studied and discussed with respect to substrate temperature. Room temperature photoluminescence (PL) spectra show the deep-level emission in the MZO thin films. The films exhibit a low electrical resistivity of 6.22 × 10^?2 Ω cm with an optical transmittance of 75% in the visible region at a substrate temperature of 623 K.     

Model-based performance analysis using block coverage measurements

The primary advantage of model-based performance analysis is its ability to facilitate sensitivity and predictive analysis, in addition to providing an estimate of the application performance. To conduct model-based analysis, it is necessary to build a performance model of an application which represents the application structure in terms of the interactions among its components, using an appropriate modeling paradigm. While several research efforts have been devoted to the development of the theoretical aspects of model-based analysis, its practical applicability has been limited despite the advantages it offers. This limited practical applicability is due to the lack of techniques available to estimate the parameters of the performance model of the application. Since the model parameters cannot be estimated in a realistic manner, the results obtained from model-based analysis may not be accurate.In this paper, we present an empirical approach in which profile data in the form of block coverage measurements is used to parameterize the performance model of an application. We illustrate the approach using a network routing simulator called Maryland routing simulator (MaRS). Validation of the performance estimate of MaRS obtained from the performance model parameterized using our approach demonstrates the viability of our approach. We then illustrate how the model could be used for predictive performance analysis using two scenarios. By the virtue of using code coverage measurements to parameterize a performance model, we integrate two mature, yet independent research areas, namely, software testing and model-based performance analysis.     

Bacterial foraging optimization technique to calculate resonant frequency of rectangular microstrip antenna

Resonant frequency of rectangular microstrip antenna having various substrate thicknesses are generally calculated using the standard expressions presented in literatures. But these equations suffer from errors when compared with the experimental values due to Quasi‐TEM propagation in the microstrip structure and fringing field. A number of researchers used soft computing approach such as neural networks and genetic algorithm on those equations to minimize the error for better accuracy. Bacterial foraging, an evolutionary optimization technique conceived in recent times, has many advantages over genetic algorithm and is yet to be applied on the design of microstrip patch antenna. In this article, a novel technique is developed to apply bacterial foraging optimization technique in conjunction with the expressions developed to calculate accurately the resonant frequency of rectangular microstrip antenna of any dimension and of any substrate thickness. Further, bacterial foraging is applied to the calculatation of the feed point of microstrip antenna. The technique developed in this article can be a generalized soft computing tool to calculate resonant frequency of rectangular microstrip antenna. Similarly, the idea of the article can be used for calculating the various parameters of microstrip antennas of different structure and geometry. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

Magnetic field induced assembling of nanoparticles in ferrofluidic liquid thin films based on NixFe1?xFe2O4

Ultra fine precursors for ferrofluid synthesis, belonging to the series, Ni _x Fe_1−x Fe₂O₄ (where ‘x’ varies from ‘0’ to ‘0.6’ in steps of 01), were synthesized. Ferrofluids based on these fine particles were prepared with oleic acid as surfactant and kerosene as carrier. Ferrofluidic thin films were made on glass substrates and magnetic field induced laser transmission was studied. The pattern exhibited by the films under the influence of a magnetic field was observed with the help of a CCD camera. The analysis of results confirms the chain formation of particles in the presence of an applied magnetic field and their saturation at higher applied fields.     

Myxobacteria ‐mediated synthesis of silver nanoparticles and their impregnation in wrapping paper used for enhancing shelf life of apples

The authors report Myxobacteria virescens (M. virescens) mediated synthesis of silver nanoparticles (AgNPs) and its efficacy against Staphylococcus aureus (ATCC‐33591), Salmonella typhi (ATCC‐51812), Escherichia coli (E. coli) (ATCC‐14948), Klebsiella pneumoniae (MTCC‐4030) and Pseudomonas aeruginosa (MTCC‐4673). The organism exhibiting resistance to various antibiotics showed remarkable sensitivity, when used in combination of antibiotics and AgNPs. Antimicrobial property of AgNPs is playing a significant role in medicine and food storage. In this study, they have used M. virescens for the synthesis of AgNPs, which were characterised by using UV‐Vis spectrophotometer, nano‐particles tracking and analysis, zeta potential, Fourier transform infrared spectroscopy, X‐ray diffraction and transmission electron microscopy. Synthesised AgNPs were impregnated into paper by three different methods, i.e. glass rod method (without binder), glass rod method (with binder) and direct synthesis of AgNPs on paper. Nanoparticles synthesis on paper showed the significant antimicrobial activity against Staphylococcus aureus (ATCC‐33591), Salmonella typhi (ATCC‐51812), E. coli (ATCC‐14948), Klebsiella pneumoniae (MTCC‐4030) and Pseudomonas aeruginosa (MTCC‐4673). Paper impregnated with AgNPs was used for wrapping of fruits (apples) which increases their shelf life up to 15 days. This study demonstrates a new method for wrapping of fruits, which increases the shelf life of apples.Inspec keywords: microorganisms, biotechnology, nanoparticles, wrapping, food packaging, antibacterial activity, ultraviolet spectra, electrokinetic effects, Fourier transform infrared spectra, X‐ray diffraction, transmission electron microscopy, food productsOther keywords: silver nanoparticles, wrapping paper impregnation, apple shelf life enhancement, Myxobacteria virescens mediated synthesis, glass rod method, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared, zeta potential, nanoparticle analysis, nanoparticle tracking, UV‐Vis spectrophotometer, antimicrobial property, antibiotic resistance, MTCC‐4673, Pseudomonas aeruginosa, MTCC‐4030, Klebsiella pneumoniae, ATCC‐14948, E. coli, Escherichia coli, ATCC‐51812, Salmonella typhi, ATCC‐33591, Staphylococcus aureus, M. virescens mediated synthesis     

Review of Recent Development of In Situ/Operando Characterization Techniques for Lithium Battery Research

The increasing demands of energy storage require the significant improvement of current Li‐ion battery electrode materials and the development of advanced electrode materials. Thus, it is necessary to gain an in‐depth understanding of the reaction processes, degradation mechanism, and thermal decomposition mechanisms under realistic operation conditions. This understanding can be obtained by in situ/operando characterization techniques, which provide information on the structure evolution, redox mechanism, solid‐electrolyte interphase (SEI) formation, side reactions, and Li‐ion transport properties under operating conditions. Here, the recent developments in the in situ/operando techniques employed for the investigation of the structural stability, dynamic properties, chemical environment changes, and morphological evolution are described and summarized. The experimental approaches reviewed here include X‐ray, electron, neutron, optical, and scanning probes. The experimental methods and operating principles, especially the in situ cell designs, are described in detail. Representative studies of the in situ/operando techniques are summarized, and finally the major current challenges and future opportunities are discussed. Several important battery challenges are likely to benefit from these in situ/operando techniques, including the inhomogeneous reactions of high‐energy‐density cathodes, the development of safe and reversible Li metal plating, and the development of stable SEI.