Colloidal processing of polymer ceramic nanocomposite integral capacitors

Polymer ceramic composites form a suitable material system for low temperature fabrication of embedded capacitors appropriate for the MCM-L technology. Improved electrical properties such as permittivity can be achieved by efficient filling of polymers with high dielectric constant ceramic powders such as lead magnesium niobate-lead titanate (PMN-PT) and barium titanate (BT). Photodefinable epoxies as the matrix polymer allow fine feature definition of the capacitor elements by conventional lithography techniques. The optimum weight percent of dispersant is tuned by monitoring the viscosity of the suspension. The dispersion mechanism (steric and electrostatic contribution) in a slightly polar solvent such as propylene glycol methyl ether acetate (PGMEA) is investigated from electrophoretic measurements. A high positive zeta potential is observed in the suspension, which suggests a strong contribution of electrostatic stabilization. By optimizing the particle packing using a bimodal distribution and modified processing methodology, a dielectric constant greater than 135 was achieved in PMN-PT/epoxy system. Suspensions are made with the lowest PGMEA content to ensure the efficiency of the dispersion and efficient particle packing in the dried film. Improved colloidal processing of nanoparticle-filled epoxy is a promising method to obtain ultra-thin capacitor films (<2/spl mu/m) with high capacitance density and improved yield. Capacitance of 35 nF/cm/sup 2/ was achieved with the thinnest films (2.5-3.0 /spl mu/m).     

Influence of additives on electrodeposition of bright Zn-Ni alloy on mild steel from acid sulphate bath

The influence of a condensation product (CP) of veratraldehyde (VRTD) and p-amino benzoic acid (PABA) on Zn-Ni alloy electrodeposited onto mild steel was studied in acidic sulphate solutions. Ethylenediaminetetraaceticacid (EDTA) and cetyltrimethylammoniumbromide (CTAB) were used as complexing and wetting agents, respectively. The effect of bath constituents, pH, current density and temperature on nature of deposit were studied through Hull cell experiments. The bath constituents and operating parameters were optimized. Deposit properties and corrosion resistance were discussed. Throwing power, current efficiency and polarization studies were carried out. SEM photomicrographs of the deposit obtained from optimum bath revealed fine-grained deposit of the alloy in the presence of condensation product and hence modified the morphology of zinc-nickel alloy deposit. IR spectrum of the scrapped deposit showed inclusion of addition agent.     

Some concepts on design of surfactant gels and vesicles

It is conjectured that anionic-cationic surfactant combination can be regarded as equivalent to a double chain surfactant and using molecular packing considerations it is shown that vesicles, viscoelastic solutions and liquid crystals can be designed by the proper choice of chain lengths of the pair. Using these concepts new systems are designed, from mixtures of cetyltrimethyl ammonium bromide and sodium alkyl sulfonates, to produce both viscoelastic gels and vesicles.     

Algorithm for converting a forest of quadtrees to a binary array

An algorithm for reconstructing a binary array of size N sx N from its forest of quadtree representation is presented. The algorithm traverses each tree of the forest in preorder and maps each ‘black’ node into the spatial domain. The time complexity in mapping is O(log N × B_n + B_p), where B_n is the number of black nodes in the forest and B_p is the number of black pixels in the N × N array. The algorithm has been implemented on an Apple II.     

L-NAME does not affect exercise-induced pulmonary hypertension in thoroughbred horses

The present study was carried out to examine the effects of nitric oxide synthase inhibition with Nomega-nitro-L-arginine methyl ester (L-NAME) on the right atrial as well as on the pulmonary arterial, capillary, and venous blood pressures of horses during rest and exercise performed at maximal heart rate (HRmax). Experiments were carried out on seven healthy, sound, exercise-trained Thoroughbred horses. Using catheter-tip manometers, with signals referenced at the point of the shoulder, we determined phasic and mean right atrial and pulmonary vascular pressures in two sets of experiments [control (no medications) and L-NAME (20 mg/kg iv given 10 min before exercise studies)]. The studies were carried out in random order 7 days apart. Measurements were made at rest and during treadmill exercise performed on a 5% uphill grade at 6, 8, and 14.2 m/s. Exercise on a 5% uphill grade at 14.2 m/s elicited HRmax and could not be sustained for >90 s. In quietly standing horses, L-NAME administration caused a significant rise in right atrial, as well as pulmonary arterial, capillary, and venous pressures. This indicates that nitric oxide synthase inhibition modifies the basal pulmonary vasomotor tone. In both treatments, exercise caused progressive significant increments in right atrial and pulmonary vascular pressures, but the values recorded in the L-NAME study were not different from those in the control study. The extent of exercise-induced tachycardia was significantly decreased in the L-NAME study at 6 and 8 m/s but not at 14.2 m/s. Thus, L-NAME administration may not modify the equine pulmonary vascular tone during exercise at HRmax. However, as indicated by a significant reduction in heart rate, L-NAME seems to modify the sympathoneurohumoral response to submaximal exercise.     

Identification of pole-like structures from mobile lidar data of complex road environment

Pole-like structures (PLSs) located in road environment are important roadway assets. They play a vital role in road safety inspection and road planning. The use of light detection and ranging (lidar) based mobile mapping technology for mapping of PLSs is an important area of research as it holds the potential for automation. Point cloud data of rural, peri-urban, and urban road environment are used in this study, which pose special challenge in view of the complexity of terrain, unlike well-planned roads, which have been the subject of interest in existing literature for identification of PLSs. A new five-step method is proposed in this article. The first two steps, i.e. ground filtering and voxelization of filtered non-ground points, are used for data size reduction. Next three steps are used to extract PLSs from reduced data. The proposed method was tested on point cloud data of three test sites having different levels of complexities. PLSs including partially occluded pole, tilted pole, pole situated very close to other objects, and vertical pole attached to tilted pole were accurately identified. Average correctness and completeness, respectively of 92.6% and 94.9%, were achieved in three different complex test sites, i.e. urban, peri-urban, and rural sites, respectively. Computation complexity shows that our proposed method delivers fast and computationally efficient solution for identifying the PLSs from volumetric mobile lidar point cloud. Impact of PLSs on road safety and road planning is also addressed for these selected test sites.     

Learning Sparse Feature Representations Using Probabilistic Quadtrees and Deep Belief Nets

Learning sparse feature representations is a useful instrument for solving an unsupervised learning problem. In this paper, we present three labeled handwritten digit datasets, collectively called n-MNIST by adding noise to the MNIST dataset, and three labeled datasets formed by adding noise to the offline Bangla numeral database. Then we propose a novel framework for the classification of handwritten digits that learns sparse representations using probabilistic quadtrees and Deep Belief Nets. On the MNIST, n-MNIST and noisy Bangla datasets, our framework shows promising results and outperforms traditional Deep Belief Networks.     

FEEDBACK CONTROL,DEVELOPMENT STRATEGY,AND MACROECONOMIC PLANNING

The amplitude of a postsynaptic potential attenuates as it spreads from the synapse to the trigger zone, where spike generation is initiated. Thus, especially in neurons with a large dendritic structure, great variability in synaptically evoked changes of the membrane potential at the trigger zone can be expected. Therefore the randomly distributed magnitudes of jumps caused by input processes were assumed in Stein's neuronal model with reversal potentials. Two distributions, normal and exponential, were applied for this purpose. The normal distribution has no influence on statistical characteristics of the interspike interval (1SI). For the exponential distribution the mean ISI, as well as the coefficient of variation, increases nonlinearly with the parameter of the distribution. The coefficient of variation is limited by the value 1. The estimation of the mean ISI by the method of Smith and Smith (1984) is not applicable for the investigated model.     

Microwave drying of mango ginger (Curcuma amada Roxb): prediction of drying kinetics by mathematical modelling and artificial neural network

Curcuma amada (Mango ginger) was dried at four different power levels ranging 315–800 W to determine the effect of microwave power on moisture content, moisture ratio, drying rate, drying time and effective diffusivity. Among the fifteen thin layer drying models considered for evaluating the drying behaviour, the semi‐empirical Midilli et al., model described the drying kinetics very well with R² > 0.999. Drying rate and effective diffusivity increased as the microwave power output increased. Activation energy was estimated by a modified Arrhenius type equation and found to be 21.6 kW kg^?1. A feed‐forward artificial neural network using back‐propagation algorithm was also employed to predict the moisture content during MW drying and found adequate to predict the drying kinetics with R² of 0.985.     

Effect of Growth Temperature on Bamboo-shaped Carbon–Nitrogen (C–N) Nanotubes Synthesized Using Ferrocene Acetonitrile Precursor

This investigation deals with the effect of growth temperature on the microstructure, nitrogen content, and crystallinity of C–N nanotubes. The X-ray photoelectron spectroscopic (XPS) study reveals that the atomic percentage of nitrogen content in nanotubes decreases with an increase in growth temperature. Transmission electron microscopic investigations indicate that the bamboo compartment distance increases with an increase in growth temperature. The diameter of the nanotubes also increases with increasing growth temperature. Raman modes sharpen while the normalized intensity of the defect mode decreases almost linearly with increasing growth temperature. These changes are attributed to the reduction of defect concentration due to an increase in crystal planar domain sizes in graphite sheets with increasing temperature. Both XPS and Raman spectral observations indicate that the C–N nanotubes grown at lower temperatures possess higher degree of disorder and higher N incorporation.