Transforming Binary Uncertainties for Robust Speech Recognition

Recently, several algorithms have been proposed to enhance noisy speech by estimating a binary mask that can be used to select those time-frequency regions of a noisy speech signal that contain more speech energy than noise energy. This binary mask encodes the uncertainty associated with enhanced speech in the linear spectral domain. The use of the cepstral transformation smears the information from the noise dominant time-frequency regions across all the cepstral features. We propose a supervised approach using regression trees to learn the nonlinear transformation of the uncertainty from the linear spectral domain to the cepstral domain. This uncertainty is used by a decoder that exploits the variance associated with the enhanced cepstral features to improve robust speech recognition. Systematic evaluations on a subset of the Aurora4 task using the estimated uncertainty show substantial improvement over the baseline performance across various noise conditions.     

Influence of Die Angle on Containerless Extrusion of Commercially Pure Titanium Tubes

Containerless tube extrusion has been investigated with commerically pure titanium at room temperature and a strain rate of 0.07 s^-1 using 20 conical dies of five different strains and four different angles with MoS₂ lubricant. Theoretical punch pressures have been calculated using appropriate equations from slab analysis of the process and compared with experimentally determined punch pressures. It is found that there exists an optimum angle at which the punch pressure is the least at a given strain.     

Evaluating different NDVI composite techniques using NOAA-14 AVHRR data

Normalized Difference Vegetation Index (NDVI) data derived from Advanced Very High Resolution Radiometer (AVHRR) data are influenced by cloud contamination, which is common in individual AVHRR scenes. Maximum value compositing (MVC) of NDVI data has been employed to minimize cloud contamination. Two types of weekly NDVI composites were built for crop seasons in summer: one from all available AVHRR data (named the traditional NDVI composite) and the other from solely cloud-free AVHRR data (named the conditional NDVI composite). The MVC method was applied to both composites. The main objective of this study was to compare the two types of NDVI composites using Texas data. The NDVI seasonal profiles produced from the conditional NDVI composites agreed with the field measured leaf area index (LAI) data, reaching maximum values at similar times. However, the traditional NDVI composites showed irregular patterns, primarily due to cloud contamination. These study results suggest that cloud detection for individual AVHRR scenes should be strongly recommended before producing weekly NDVI composites. Appropriate AVHRR data pre-processing is important for composite products to be used for short-term vegetation condition and biomass studies, where the traditional NDVI composite data do not eliminate cloud-contaminated pixels. In addition, this study showed that atmosphere composition affected near-infrared reflectance more than visible reflectance. The near-infrared reflectance was increasingly adjusted through atmospheric correction.     

Contribution of organomodified clay on hybrid microstructures and properties of epoxidized natural rubber‐based nanocomposites

Influence of organic modifying agent of clay on dispersion, distribution, hybrid microstructure formation, and associated performance properties of epoxidized natural rubber‐based composites was evaluated. Binary and ternary composites of carbon black (CB) and two organomodified layered silicates (i.e., nanomer I30E and Cloisite 30B) were prepared and characterized based on small angle X‐ray scattering, transmission electron microscopy, hydrodynamic swelling, tensile measurement, and dynamic mechanical analyses. Greater extent of exfoliation and “nanounit” formation was noted in ternary composites containing nanomer I30E, which was reflected in higher interfacial roughness (d_s = 2.82) and lower radius of gyration (R_g = 205 Å). Morphological observations suggested higher nanomer I30E–CB interactions than that of Cloisite 30B–CB. The interplatelet distance in Cloisite 30B (d = 1.83 nm) stacks was lower than that of nanomer I30E (d = 2.26 nm). These two factors jointly contributed in higher breakdown of nanomer I30E stacks by CB than that of Cloisite 30B stacks. Greater exfoliation and nanounit formation in I30E–CB‐filled nanocomposite was also reflected in increased degree of crosslinking (n = 20 × 10^?5%), tensile modulus/strength, half height width of damping peak (20.3°C), and filler effectiveness (C = 0.33). POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

One‐Dimensional Pseudo‐Homogeneous Packed‐Bed Reactor Modeling: I. Chemical Species Equation and Effective Diffusivity

Packed‐bed reactor experimentation is a key tool used in order to formulate chemical kinetics. The chemical species equation and overall methodology are described for a one‐dimensional pseudo‐homogeneous packed‐bed reactor model useful for experimental calibration of chemical kinetics. Over the history of simulation development for this equation there exist numerous different effective diffusivity correlations. The included historical review and parametric study of these correlations help to determine the correct choice based on numerical simplicity and model outcomes. A subsequent review paper describes the energy equation and effective thermal conductivity correlations while coming to a generalized conclusion regarding modeling efforts.     

Inverted emulsion polymerization route to polyaniline‐3D nanofiber network using sulfonated‐p‐cresol as novel dopant

Sulfonated‐p‐cresol (SPC) was used as novel dopant for the first time in the synthesis of polyaniline in 3D nanofiber networks (PANI‐3D). Polyaniline in 3D nanofiber network was prepared using organic solvent soluble benzoyl peroxide as oxidizing agent in presence of SPC and sodium lauryl sulfate (SLS) surfactant via inverted emulsion polymerization pathway. The influence of synthesis conditions such as the concentration of the reactants, stirring/static condition, and temperature etc., on the properties and formation of polyaniline nanofiber network were investigated. Polyaniline in 3D nanofiber network with 40–160 nm (diameter), high yield (134 wt % with respect to aniline used), and reasonably good conductivity (0.1 S/cm) was obtained in 24 h time. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Micromechanical modelling of switching phenomena in polycrystalline piezoceramics: application of a polygonal finite element approach

A micromechanically motivated model is proposed to capture nonlinear effects and switching phenomena present in ferroelectric polycrystalline materials. The changing remnant state of the ferroelectric crystal is accounted for by means of so-called back fields—such as back stresses—to resist or assist further switching processes in the crystal depending on the local loading history. To model intergranular effects present in ferroelectric polycrystals, the computational model elaborated is embedded into a mixed polygonal finite element approach, whereby an individual ferroelectric grain is represented by one single irregular polygonal finite element. This computationally efficient coupled simulation framework is shown to reproduce the specific characteristics of the responses of ferroelectric polycrystals under complex electromechanical loading conditions in good agreement with experimental observations.     

KINETICS OF URANIUM EXTRACTION BY MACROPOROUS BIFUNCTIONAL PHOSPHINIC ACID RESIN

ABSTRACT

The rate of extraction of uranium by macroporous bifunctional phosphinic acid (MPBPA) resin from nitric acid medium has been studied under particle diffusion controlled conditions. The internal diffusion coefficient was found to increase with increase in temperature and decrease with increase in particle size. The activation energies and entropies suggest that the extraction of uranium essentially follows ion exchange mechanism at low concentration of nitric acid while it is through linkage of >P=0 group of the resin at high concentrations.     

Decolourisation of leather dye by ozonation

Sewage and industrial effluent treatment plants are installed with primary and secondary biological treatment units to reduce the discharge of pollution load into the environment. These treatment plants normally reduce the organic load in terms of BOD but not the pollution load in terms of inorganic salts (total dissolved solids—TDS) and colour in the effluent. To eliminate the contamination of ground and surface water bodies and to conserve water sources, the regulatory authorities have taken very stringent regulations to implement zero liquid discharge (ZLD) for industrial effluents, i.e., water recovery from wastewater and reuse. It is difficult to recover water from secondary treated wastewater directly, as it does not meet the reverse osmosis feed requirements. In order to achieve the feed requirements, different tertiary treatment methods are being tried. In this study, removal of colour due to residual dyes has been attempted using ozone. The main purpose of this study is to decolourise the dye used in leather processing. Also, the effect of pH and dye concentration on dye decolourisation has been investigated. From the study it has been observed that maximum decolourisation efficiency up to 97% could be achieved for the pH values (4,7, 9 and 11) and dye concentrations (30, 65, 180 and 360 mg/L) studied.     

Clay-catalysed dealkylation of organic sulfides

Both K10- as well as modified montmorillonites such as cation-exchanged and surfactant-pillared clays catalyse the cleavage of carbon–sulfur single bonds resulting in dealkylation of organic sulfides. The corresponding disulfides are obtained in high yield. This revised version was published online in July 2006 with corrections to the Cover Date.