Thermomechanically stable dielectric composites based on poly(ether ketone) and BaTiO3 with improved electromagnetic shielding properties in X‐band

High‐performance barium titanate (BaTiO₃) filled poly(ether ketone) (PEK) composites were prepared by melt compounding with an aim to investigate the effect of BaTiO₃ on thermal, thermomechanical, dielectric, and electromagnetic interference shielding behavior of PEK. The content of BaTiO₃ in the PEK matrix was varied from 0 to 18 vol %. Scanning electron microscopy studies shows that BaTiO₃ particles were uniformly distributed in the PEK matrix up to 13 vol % loading followed by the formation of agglomerates at higher loading (18 vol %). Rockwell hardness increased up to 13 vol % loading followed by a decrease at 18 vol % loading. Dynamic mechanical analysis revealed that storage modulus increases with increase in BaTiO₃ loading with a maximum value of 3192 MPa at 13 vol % compared to 2099 MPa for neat PEK. Dielectric constant of composites measured in the frequency range of 8.2–12.4 GHz increased approximately three times upon incorporation of 18 vol % of BaTiO₃. This increment in dielectric constant is reflected in improved electromagnetic shielding properties as loading of dielectric filler (BaTiO₃) increases. Total shielding effectiveness of ?11 dB (～92% attenuation) at loading of 18 vol % BaTiO₃ justifies the use of these composites for suppression of EM radiations. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46413.     

Synthesis and characterization of modified cottonseed oil based polyesteramide for coating applications

Cottonseed oil fatty amide (CFA) was prepared in the laboratory by base catalyzed aminolysis of cottonseed oil. Further it was reacted with phthalic acid to obtain polyesteramide (CPEA) and modified by post reacting with vinyl acetate monomer in varying ratios of 4:1, 3:1 and 2:1 in the presence of t-butyl hydroperoxide as an initiator. The incorporation of vinyl acetate in CPEA was analyzed using FTIR, ¹H NMR and ¹³C NMR spectral techniques. The physico-chemical properties such as iodine value, specific gravity and refractive index were determined by standard laboratory test methods. Mechanical, chemical resistance and other coating properties of the coatings synthesized from CPEA and modified CPEA applied on mild steel substrates were also studied by standard methods. Thermal stability and curing behavior of modified CPEA were determined by thermo gravimetric analysis (TGA) and differential scanning calorimetric (DSC) techniques. It was observed that modification of polyesteramide improved the curing, mechanical and chemical performance of CPEA films. It was found that among the CPEA:vinyl acetate ratios, 2:1 ratio exhibited the best results.     

MICROWAVE DRYING : EFFECTS ON PAPER PROPERTIES

Effects of microwave drying on the mechanical and optical properties of handsheets made from kraft and chemi-thermomechanical pulps were studied experimentally. The quality of paper dried in a microwave field of 2450 MHz is compared with that of paper dried by conventional method under standard conditions. All properties were found to be either enhanced or at the same level as those obtained under standard conditions. Since microwave field allows volumetric heating of moisture, the drying time is much shorter due to reduced resistance to heat and mass transfer within the paper. Furthermore, it is suggested that microwave drying could replace the conventional drying method in the standard testing of pulp and paper samples for quality control purposes.     

Rough set based 1-v-1 and 1-v-r approaches to support vector machine multi-classification

Support vector machines (SVMs) are essentially binary classifiers. To improve their applicability, several methods have been suggested for extending SVMs for multi-classification, including one-versus-one (1-v-1), one-versus-rest (1-v-r) and DAGSVM. In this paper, we first describe how binary classification with SVMs can be interpreted using rough sets. A rough set approach to SVM classification removes the necessity of exact classification and is especially useful when dealing with noisy data. Next, by utilizing the boundary region in rough sets, we suggest two new approaches, extensions of 1-v-r and 1-v-1, to SVM multi-classification that allow for an error rate. We explicitly demonstrate how our extended 1-v-r may shorten the training time of the conventional 1-v-r approach. In addition, we show that our 1-v-1 approach may have reduced storage requirements compared to the conventional 1-v-1 and DAGSVM techniques. Our techniques also provide better semantic interpretations of the classification process. The theoretical conclusions are supported by experimental findings involving a synthetic dataset.     

Short-Term Traffic Prediction on Different Types of Roads with Genetically Designed Regression and Time Delay Neural Network Models

Research for advanced traveler information systems (ATIS) has been focused on urban roads. However, research for short-term traffic prediction on all categories of highways is needed, as highway agencies expect to implement intelligent transportation systems across their jurisdictions. In this study, genetic algorithms were used to design time delay neural network (TDNN) models as well as locally weighted regression models to predict short-term traffic for six rural roads from Alberta, Canada. These roads are from various trip-pattern groups and functional classes. Refined TDNN models developed in this study can limit most average errors less than 10% for all study roads. Refined regression models show even higher accuracy. Average errors for the refined regression models are less than 2% for roads with stable patterns. Even for roads with unstable patterns, average errors are below 4%, and the 95th percentile errors are less than 7%. It is believed that such accurate predictions would be useful for highway agencies to implement statewide ATIS.     

Face Recognition by Computers and Humans

Research into face recognition offers research opportunities that will challenge scientists and engineers for years to come. Robust face-recognition systems, for example, can be used in projects related to homeland security, human-computer interaction, and many consumer applications.     

Structural and Thermo-Physical Properties of 3C-SiC: High-Temperature and High-Pressure Effects

Silicon - Based on the density functional theory (DFT), a systematic theoretical investigation on the structural parameters and finite temperature thermo-physical properties of cubic silicon...     

Modification of structural,thermal, and electrical properties of PVA by addition of silicon carbide nanocrystals

SiC‐PVA nanocomposite films, synthesized using solution‐casting technique were structurally characterized using X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Morphological studies of the SiC‐PVA nanocomposite films were carried out using Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). TEM analysis confirms that the size of SiC nanocrystals present in PVA matrix are 23 ± 9 nm, which is consistent with size calculated using XRD. SiC‐PVA nanocomposite films were further characterized for their thermal and electrical properties. Thermogravimetric/differential thermal analysis (TG/DTA) indicates that the char yield of nanocomposite films containing 3 wt % SiC nanocrystal is ～30% more than PVA. This increase in char yield is an indication of the potency of flame retardation of SiC‐PVA nanocomposite films. I‐V analysis reveals that Schottky mechanism is the dominant conduction mechanism which is responsible for the increase in conductivity of PVA with the addition of SiC nanocrystals. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42464.     

Feature-specific structured imaging

We present a feature-specific imaging system based on the use of structured light. Feature measurements are obtained by projecting spatially structured illumination onto an object and collecting all the reflected light onto a single photodetector. Principal component features are used to define the illumination patterns. The optimal linear minimum mean-square error (LMMSE) operator is used to generate object estimates from the measured features. We study the optimal allocation of illumination energy into each feature measurement in the presence of additive white Gaussian detector noise and optical blur. We demonstrate that this new imaging approach reduces imager complexity and provides improved image quality in high noise environments. Compared to the optimal LMMSE postprocessing of a conventional image, feature-specific structured imaging provides a 38% rms error reduction and requires 400 times fewer measurements for a noise standard deviation of sigma = 2 x 10(-3). Experimental results validate these theoretical predictions.     

Dielectric,ferroelectric and bipolar electric field induced strain properties of MPB composition of NBT-xKNN system

(1-x) (Na_0.5Bi_0.5TiO₃)-xK_0.5Na_0.5NbO₃/NBT-xKNN [x?=?0.07, 0.06, 0.05] ferroelectric ceramics were prepared by solid state synthesis route (SSSR). The effects of KNN contents on the microstructure, dielectric, piezoelectric and ferroelectric properties of the NBT-xKNN system were investigated in detail. For single perovskite phase formation, the calcination temperature was optimized at 800 °C for 6 h. From the XRD study, the morphotropic phase boundary (MPB) was confirmed for x?=?0.07 composition. For better densification, the sintering temperature was optimized for 1150 °C for 4 h. SEM micrographs illustrate the closely packed and non-uniform distribution of grains. Diffusive type of behaviour was observed in all the ceramics. Polarization (P) vs. electric field (E) study confirmed the ferroelectric nature of the NBT-xKNN ceramics. The bipolar field-induced strain measurement for all the ceramic samples showed butterfly-shaped loops indicating their piezoelectric nature. Among all the different compositions in MPB region, high dielectric constant (ε_r) of?~?3011, high remnant polarization (P _r ) of 17.88μC/cm² and high strain % of 0.41, were obtained in NBT-xKNN system with x?=?0.07 confirming the existence of MPB at this composition.