Audio Signal Processing Using Time-Frequency Approaches: Coding, Classification, Fingerprinting, and Watermarking

Audio signals are information rich nonstationary signals that play an important role in our day-to-day communication, perception of environment, and entertainment. Due to its non-stationary nature, time- or frequency-only approaches are inadequate in analyzing these signals. A joint time-frequency (TF) approach would be a better choice to efficiently process these signals. In this digital era, compression, intelligent indexing for content-based retrieval, classification, and protection of digital audio content are few of the areas that encapsulate a majority of the audio signal processing applications. In this paper, we present a comprehensive array of TF methodologies that successfully address applications in all of the above mentioned areas. A TF-based audio coding scheme with novel psychoacoustics model, music classification, audio classification of environmental sounds, audio fingerprinting, and audio watermarking will be presented to demonstrate the advantages of using time-frequency approaches in analyzing and extracting information from audio signals.</p

Eosin Yellowish Dye-Sensitized ZnO Nanostructure-Based Solar Cells Employing Solid PEO Redox Couple Electrolyte

ZnO nanostructures are synthesized by low-temperature methods, and they possess polycrystalline hexagonal wurtzite structure with preferential c-axial growth. Morphological study by SEM shows the presence of ~30 nm sized spherical-shaped ZnO nanoparticle, the branched flower-like ZnO composed of many nanorods (length: 1.2 to 4.2 μm and diameter: 0.3 to 0.4 μm), and ~50 nm diameter of individual ZnO nanorods. Reduction in photoemission intensity of nanorods infers the decrease in electron-hole recombination rate, which offers better photovoltaic performance. The dye-sensitized solar cell (DSSC) based on ZnO nanorods sensitized with Eosin yellowish dye exhibits a maximum optimal energy conversion efficiency of 0.163% compared to that of nanoparticles and nanoflowers, due to better dye loading and direct conduction pathway for electron transport

Efficiency of single and di- site phase transfer catalyzed polymerization of glycidyl methacrylate in the two-phase system: A kinetic study

In the present kinetic study, glycidyl methacrylate has been polymerized using synthesized single-site phase transfer catalyst - 2-benzoylethyldecyldimethylammonium bromide and di-site –phase transfer catalyst -1,1,4,4-tetramethyl-1,4 dioctylethylenediammonium bromide along with potassium peroxydisulfate as the initiator in inert medium and at a constant temperature of 60°C. The effect of concentrations of the monomer, initiator, catalyst, ionic strength, pH and solvent polarity on the rate of polymerization has been examined. The order with respect to the monomer, initiator, and phase transfer catalyst was found to be 1, 0.5, and 0.5, respectively. A suitable polymerization mechanism is proposed. Ionic strength and pH has no impact on the rate of polymerization. It is observed that, as the solvent's polarity increased, the rate of polymerization also increased. Di-site phase transfer catalyst results in a higher rate of polymerization compared with single-site phase transfer catalyst while polymerizing glycidyl methacrylate

Corrosion inhibition efficiency of newly synthesized quaternary ammonium salt in 1M HCl

68-74The newly synthesized quaternary ammonium salt, 1, 4-Bis (dimethyl decyl) ethylene diammonium bromide has been characterized by FT-IR, 1H NMR, 13C NMR. It has been examined for its corrosion efficiency by the weight loss method by immersing in a 1M HCl solution. The surface morphology is characterized using Scanning Electron Microscopy and it exhibited the variation between corroded surface and inhibited surface of carbon steel.Energy-Dispersive X-ray spectroscopy also shown the differences in composition of the corroded and surface coated with inhibitor. The efficiency of the inhibitor is investigated by varying the concentration of the inhibitor from 100 to 500 ppm and over a temperature range from 25 to 45C. Inhibitor efficiency is maximum in the concentration range of 500 ppm and found to be 77.75% at 45C. The plot of concentration against surface coverage revealed that, the present system follows Langmuir’s adsorption isotherm. Compared to acidic medium, inhibitor excelled its maximum efficiency in the neutral medium

Efficiency of single and di- site phase transfer catalyzed polymerization of glycidyl methacrylate in the two-phase system: A kinetic study

445-452In the present kinetic study, glycidyl methacrylate has been polymerized using synthesized single-site phase transfer catalyst - 2-benzoylethyldecyldimethylammonium bromide and di-site –phase transfer catalyst -1,1,4,4-tetramethyl-1,4 dioctylethylenediammonium bromide along with potassium peroxydisulfate as the initiator in inert medium and at a constant temperature of 60°C. The effect of concentrations of the monomer, initiator, catalyst, ionic strength, pH and solvent polarity on the rate of polymerization has been examined. The order with respect to the monomer, initiator, and phase transfer catalyst was found to be 1, 0.5, and 0.5, respectively. A suitable polymerization mechanism is proposed. Ionic strength and pH has no impact on the rate of polymerization. It is observed that, as the solvent's polarity increased, the rate of polymerization also increased. Di-site phase transfer catalyst results in a higher rate of polymerization compared with single-site phase transfer catalyst while polymerizing glycidyl methacrylate

Deficiency in Lyst function leads to accumulation of secreted proteases and reduced retinal adhesion.

Chediak-Higashi syndrome, caused by mutations in the Lysosome Trafficking Regulator (Lyst) gene, is a recessive hypopigmentation disorder characterized by albinism, neuropathies, neurodegeneration, and defective immune responses, with enlargement of lysosomes and lysosome-related organelles. Although recent studies have suggested that Lyst mutations impair the regulation of sizes of lysosome and lysosome-related organelle, the underlying pathogenic mechanism of Chediak-Higashi syndrome is still unclear. Here we show striking evidence that deficiency in LYST protein function leads to accumulation of photoreceptor outer segment phagosomes in retinal pigment epithelial cells, and reduces adhesion between photoreceptor outer segment and retinal pigment epithelial cells in a mouse model of Chediak-Higashi syndrome. In addition, we observe elevated levels of cathepsins, matrix metallopeptidase (MMP) 3 and oxidative stress markers in the retinal pigment epithelium of Lyst mutants. Previous reports showed that impaired degradation of photoreceptor outer segment phagosomes causes elevated oxidative stress, which could consequently lead to increases of cysteine cathepsins and MMPs in the extracellular matrix. Taken together, we conclude that the loss of LYST function causes accumulation of phagosomes in the retinal pigment epithelium and elevation of several extracellular matrix-remodeling proteases through oxidative stress, which may, in turn, reduce retinal adhesion. Our work reveals previously unreported pathogenic events in the retinal pigment epithelium caused by Lyst deficiency. The same pathogenic events may be conserved in other professional phagocytic cells, such as macrophages in the immune system, contributing to overall Chediak-Higashi syndrome pathology