Adaptive nonuniform polar quantization application to high quality speech compression

The logarithmic companding technique has shown to be extremely useful in speech quantization with rate of 8 bits/sample. However, for lower bit rates it is not the ideal solution for high quality speech coding. Because of that, in this paper we establish source coding scheme which enables better spectrum efficiency for input that has a large dynamic range. Since our wish is also to improve signal quality in comparison with quality defined with standards G.711 and G.712, we opt for adaptive technique application to the speech coding. Our research shows that proper design of forward gain-adaptive polar quantization can enable compression of about 1 bit/sample as well as significantly better quality than in case of using coder designed according to standard G.711. Furthermore, performances can be sustained over the whole speech dynamic range. Also, if the requisite speech quality is not supposed to be lower than G.712 standard quality, the achieved compression can be almost 1.5 bits/sample. Besides, we propose knew simple encoding rule which can additionally reduce bit rate for 0.1 bit/sample.     

Collapse of acrylamide‐based polyampholyte hydrogels in water

The swelling behavior of balanced acrylamide (AAm)‐based polyampholyte hydrogels in water and in aqueous salt (NaCl) solutions was investigated. Equimolar ratio of the ionic comonomers 4‐vinylpyridine (cationic monomer) and acrylic acid (anionic monomer) were used together with the nonionic monomer AAm in the hydrogel preparation. The variations of the hydrogel volume in response to changes in pH were measured. It was found that the hydrogels are in a collapsed state not only at the pH of the isoelectric point pH_IEP but also over a wide range of pH including pH_IEP. The width of the collapsed plateau increased and the hydrogels assumed a more compact state as the ionic group content is increased. The antipolyelectrolyte behavior was observed along the collapsed plateau region, where the gel occupies a larger volume in salt solution. The experimental swelling data were compared with the predictions of the Flory‐Rehner theory of swelling equilibrium including the ideal Donnan equilibria. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Adsorption of cationic polyacrylamide onto sepiolite

The adsorption of PAM onto sepiolite from aqueous solutions has been investigated systematically as a function of some parameters such as calcination temperature of sepiolite, pH, ionic strength and temperature. The adsorption of cationic polyacrylamide (PAM) increases with pH from 5.50 to 11.00, temperature from 25 to 55 degrees C and ionic strength from 0 to 0.1molL(-1). The sepiolite sample calcined at 200 degrees C has a higher adsorption capacity than the other calcined samples. Adsorption isotherms of PAM onto sepiolite have been determined and correlated with common isotherm equations such as Langmuir and Freundlich isotherm models. The Langmuir isotherm model appeared to fit the isotherm data better than the Freundlich isotherm model. The physical properties of this adsorbent are consistent with the parameters obtained from the isotherm equations. The zeta potentials of sepiolite suspensions have been measured in aqueous solutions of NaCl and different PAM concentrations and pH. From the experimental results: (i) pH strongly alters the zeta potential of sepiolite, (ii) sepiolite has an isoelectric point at about pH 6.6 in water and about pH 8 in 250mgL(-1) PAM concentration, (iii) PAM changes the interface charge from negative to positive for sepiolite. Effect of temperature on adsorption has been quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy. The dimensionless separation factor (R(L)) has shown that sepiolite can be used for adsorption of PAM from aqueous solutions.     

Prediction of postpartum depression using machine learning techniques from social media text

Early screening of mental disorders plays a crucial role in diagnosis and treatment. This study explores how data‐driven methods can leverage the information available on social media platforms to predict postpartum depression (PPD). A generalized approach is proposed where linguistic features are extracted from user‐generated textual posts on social media and categorized as general, depressive, and PPD representative using multiple machine learning techniques. We find that techniques used in our study exhibit strong predictive capabilities for PPD content. Holdout validation showed that multilayer perceptron outperformed other techniques such as support vector machine and logistic regression used in this study with 91.7% accuracy for depressive content identification and up to 86.9% accuracy for PPD content prediction. This work adopts a hierarchical approach to predict PPD. Therefore, the reported PPD accuracy represents the performance of the model to correctly classify PPD content from non‐PPD depressive content.     

Two La0.5Ag0.1Ca0.4MnO3 Manganite Nanoparticles Synthesized via Sol–Gel and Solid-State Methods–Structural,Magnetic, and Magnetocaloric Properties

Journal of Superconductivity and Novel Magnetism - La0.5Ag0.1Ca0.4MnO3 manganite nanoparticles are synthesized via two different ways, namely, a solid-state reaction (S1) and the sol–gel...     

Green Adeptness in the Synthesis and Stabilization of Copper Nanoparticles: Catalytic,Antibacterial, Cytotoxicity,and Antioxidant Activities

Copper nanoparticles (CuNPs) are of great interest due to their extraordinary properties such as high surface-to-volume ratio, high yield strength, ductility, hardness, flexibility, and rigidity. CuNPs show catalytic, antibacterial, antioxidant, and antifungal activities along with cytotoxicity and anticancer properties in many different applications. Many physical and chemical methods have been used to synthesize nanoparticles including laser ablation, microwave-assisted process, sol-gel, co-precipitation, pulsed wire discharge, vacuum vapor deposition, high-energy irradiation, lithography, mechanical milling, photochemical reduction, electrochemistry, electrospray synthesis, hydrothermal reaction, microemulsion, and chemical reduction. Phytosynthesis of nanoparticles has been suggested as a valuable alternative to physical and chemical methods due to low cytotoxicity, economic prospects, environment-friendly, enhanced biocompatibility, and high antioxidant and antimicrobial activities. The review explains characterization techniques, their main role, limitations, and sensitivity used in the preparation of CuNPs. An overview of techniques used in the synthesis of CuNPs, synthesis procedure, reaction parameters which affect the properties of synthesized CuNPs, and a screening analysis which is used to identify phytochemicals in different plants is presented from the recent published literature which has been reviewed and summarized. Hypothetical mechanisms of reduction of the copper ion by quercetin, stabilization of copper nanoparticles by santin, antimicrobial activity, and reduction of 4-nitrophenol with diagrammatic illustrations are given. The main purpose of this review was to summarize the data of plants used for the synthesis of CuNPs and open a new pathway for researchers to investigate those plants which have not been used in the past.

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Graphical abstract Proposed Mechanism for Antibacterial activity of copper nanoparticles.

     

Use of o-phenylene dioxydiacetic acid impregnated in Amberlite XAD resin for separation and preconcentration of uranium(VI) and thorium(IV)

The impregnation of o-phenylene dioxydiacetic acid (OPDA) into a polymeric matrix, Amberlite XAD-2000, is reported and was characterized by infrared spectroscopy. The amount of attached OPDA to the polymer resin was found to be 1.77mmolg(-1) resin. The resin was used for the sorption of U(VI) and Th(IV) from aqueous solution. This sorbent was capable of preconcentrating U(VI) and Th(IV) from weakly acidic or neutral solution. The retained metals were eluted sequentially using 0.25molL(-1) HCl for U(VI) and 1molL(-1) HCl for Th(IV) and determined spectrophotometrically using arsenazo-(III). The capacity of the resin for U(VI) and Th(IV) was found to be 0.121 and 0.113mmolg(-1), respectively. The impregnated resin exhibits a high chemical stability, reusability and fast equilibration. The method was used for the determination of U(VI) and Th(IV) in synthetic samples and rock samples.     

High birefringence photonic crystal fiber with a complex unit cell of asymmetric elliptical air hole cladding

High birefringence induced by elliptical air hole photonic crystal fibers (EHPCFs) is analyzed numerically using the finite-element method. Statistical correlations between the birefringence and the various parameters are obtained. We found that the complex elliptical air hole is better than that of a circular one to obtain high birefringence in photonic crystal fibers. Our suggested structures can considerably enhance the birefringence in EHPCFs and show that the birefringence can be as high as 1.1294 x 10(-2), which is higher than the birefringence obtained from conventional step-index fiber (5 x 10(-4)), circular air holes PCF (3.7 x 10(-3)), and elliptical hollow PCF (2.35 x 10(-3)).     

Applied and Emerging Methods for Meat Tenderization: A Comparative Perspective

The tenderization process, which can be influenced by both pre‐ and post‐slaughter interventions, begins immediately after an animal's death and is followed with the disruption of the muscle structure by endogenous proteolytic systems. The post‐slaughter technological interventions like electrical stimulation, suspension methods, blade tenderization, tumbling, use of exogenous enzymes, and traditional aging are some of the methods currently employed by the meat industry for improving tenderness. Over the time, technological advancement resulted in development of several novel methods, for maximizing the tenderness, which are being projected as quick, economical, nonthermal, green, and energy‐efficient technologies. Comparison of these advanced technological methods with the current applied industrial methods is necessary to understand the feasibility and benefits of the novel technology. This review discusses the benefits and advantages of different emerging tenderization techniques such as hydrodynamic‐pressure processing, high‐pressure processing, pulsed electric field, ultrasound, SmartStretch^?, Pi‐Vac Elasto‐Pack® system, and some of the current applied methods used in the meat industry.     

Using flower pollinating with artificial bees (FPAB) technique to determine machinable volumes in process planning for prismatic parts

Process planning (PP) has an important role in manufacturing systems design and operations. Volume decomposition and machinable volumes (MVs) or machining features determination is the core activity in process planning. This process requires extraction of elementary volumes (EVs), merging or clustering EVs to construct feasible MVs and finally selecting an optimal combination of MVs. Development of MVs is an important activity, so that better solution is obtained by better developed MVs. Generation of limited number of MVs or machining features, which is often performed by experts may miss the optimal solution. Also, using exact methods such as combinatorial optimization not only generate infeasible MVs, but also require an excessive amount of computational time. In this research, the meta-heuristic procedure of flower pollinating by artificial bees (FPAB) is used in manufacturing context to generate and assess the feasibility of MVs. Furthermore, a set-covering method is used to select the optimal solution. The performance of the proposed model is assessed through some numerical examples. The encouraging results of the numerical examples demonstrate good performance of the proposed method in machining feature or machinable volumes determination problem (MVDP).