A faster path planner using accelerated particle swarm optimization

The idea of placing small mobile robots to move around in a large building to detect potential intruders has been around for some time. However, there are still two major hurdles to overcome: to locate itself in the environment and to make a decision on how to move around safely and effectively at a reasonable computation cost. This paper describes a mathematical model for developing a scheme for an autonomous low cost mobile robot system using visual simultaneous localization and mapping and accelerated particle swarm intelligent path planner. The results indicated that this system could provide a solution for the problem of indoor mobile robot navigation. Advances in computer technology make this technique a cost effective solution for a future home service robot.     

Dielectric Modulus and Conductivity Scaling Approach to the Analysis of Ion Transport in Solid Polymer Electrolytes

Solid polymer electrolyte films (SPEs) based on poly(methyl methacrylate) are prepared using a solution cast technique. The temperature-dependent behavior of dielectric, modulus spectra and ac conductivity has been investigated. The long tail of the real part of modulus (M′) in the low frequency indicates the capacitive nature of the samples. The frequency dependence of imaginary part of modulus (M″) shows a non-Debye relaxation that has been explained using the Kohlrausch–Williams–Watts stretched exponential function. The activation energy for the relaxation is almost same as the activation energy for the conduction. The relaxation time obtained from the tangent loss graph (τ_δ) is about two orders of magnitude larger than that obtained from the imaginary part of modulus graph (τ_m). The ac conductivity has been found to obey Jonscher's universal power law. Transport parameters show that addition of filler creates additional hopping sites for the charge carriers and also increases the charge carrier density. It is also observed that the higher ionic conductivity at higher temperature is due to increased thermally activated hopping rates accompanied by a significant increase in carrier concentration. The contribution of carrier concentration to the total conductivity is also confirmed from Summerfield scaling. POLYM. ENG. SCI., 60: 297–305, 2019. © 2019 Society of Plastics Engineers     

The Gambling Urge Scale: Development, Confirmatory Factor Validation, and Psychometric Properties.

The urge to gamble is a physiological, psychological, or emotional motivational state, often associated with continued gambling. The authors developed and validated the 6-item Gambling Urge Questionnaire (GUS), which was based on the 8-item Alcohol Urge Questionnaire (M. J. Bohn, D. D. Krahn, & B. A. Staehler, 1995), using 968 community-based participants. Exploratory factor analysis using half of the sample indicated a 1-factor solution that accounted for 55.18% of the total variance. This was confirmed using confirmatory factor analysis with the other half of the sample. The GUS had a Cronbach's alpha coefficient of .81. Concurrent, predictive, and criterion-related validity of the GUS were good, suggesting that the GUS is a valid and reliable instrument for assessing gambling urges among nonclinical gamblers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Micellization Behavior of Cationic Gemini Surfactants in Aqueous-Ethylene Glycol Solution

The micellization behavior of gemini surfactants i.e. alkanediyl-α,ω-bis(cetyldimethylammonium bromide) (C₁₆-s-C₁₆,2Br⁻ where s = 3, 4, 10) in 10% (v/v) ethylene glycol solution was investigated by surface tension and conductometric measurements at 300 K. The critical micelle concentration, degree of micellar ionization, surface excess concentration, minimum surface area per molecule of surfactant, surface pressure at the CMC and Gibbs energy of adsorption of the dimeric surfactants have also been determined in the presence of different salts (NaCl, NaBr and NaI). The critical micelle concentration and degree of micellar ionization values decrease significantly in the presence of sodium halides and follows the sequence NaCl < NaBr < NaI. The free energy, enthalpy and entropy of micellization of dimeric surfactants in 10% (v/v) ethylene glycol solution were determined using the temperature dependence of the critical micelle concentration. The standard free energy of micellization was found to be negative in all the cases.     

Dielectric relaxation and thermal studies on dispersed phase polymer nanocomposite films

Dispersed phase polymer nanocomposite films (PNC) based on PMMA–LiClO₄+ n-YSZ, has been prepared. The effect of filler concentration on dielectric constant, tanδ and ac conductivity has been observed. For each PNC films the activation energy for relaxation (E_τ) is almost same as the activation energy for ion conduction (E_a). The dc conductivity, the hopping frequency of charge carriers have been obtained at different temperature from the analysis of the ac conductivity data. For all the PNC films, the concentration of charge carriers has been calculated at different temperature using Almond–West formalism. The estimated activation energies for the dc conductivity and the hopping frequency are different, which indicates that the both charge carrier mobility and concentration contribute significantly to the ionic conductivity of polymeric electrolyte. Contribution of charge carrier mobility to the total conductivity has also been confirmed from the differential scanning calorimetry analysis. Improvement in thermal stability has been noticed with filler addition.     

Isolation and Identification of Lactobacillus plantarum from Vegetable Samples

Lactobacillus plantarum, a non-pathogenic species of lactic acid bacteria, has considerable industrial and medical interest. It is used as starter culture in food and feed fermentation. For developing new starter culture usually needs identification from natural sources. Many literatures are available for its definite identification. But ambiguous results of phenotypic characterization and application of laborious and expensive molecular approaches has generated the need of a rapid molecular assay. Therefore, a specific PCR assay is described which exploits PCR amplification of conserved gene sequences encoding for plantaricin biosynthesis protein by designed species specific primer pair plnX (F/R). This has generated 228 bp amplicons with test and positive controls. This assay was established by six genotypically identified test strains of vegetable samples, two positive and four negative controls. The described assay could be used for preliminary screening of L. plantarum from large samples before performing a battery of phenotypic and molecular methods.     

Sintering and electromagnetic properties of BaFe12O19 ferrite prepared by co-precipitation method

BaFe₁₂O₁₉ (BaM) was synthesized through the co-precipitation route. Pure phase BaM was formed after calcination of precipitated powder at 900 °C. BaM was sintered at three different temperatures; 1100, 1200, and 1300 °C to study the sintering kinetics by varying the sintering time from 1 to 4 h. Apparent porosity decreased, and bulk density increased with increasing sintering temperature and period. A bulk density of about 4.6 g/cm³ was achieved after sintering at 1300 °C/4 h. The rate-controlling mechanism of BaM densification was the diffusion of oxygen, and the activation energy for the sintering process was 274 kJ/mol. The grain size of BaM increased with rising sintering temperatures. Permittivity increased from about 11 to 17 and the permeability increased from about 10 to 16 with the increase in sintering temperature from 1100 to 1300 °C. Saturation magnetization was also enhanced to about 69 emu/g after sintering at 1300 °C/4 h. Therefore, BaM ferrite synthesized through the co-precipitation route can be effectively used for high-frequency applications after sintering at 1300 °C.

     

Multipass FSP on AA6063-T6 Al: Strategy to fabricate surface composites

Surface composites were fabricated on AA6063-T6 base metal using silicon carbide (SiC) reinforcement particles by friction stir processing (FSP). Influence of multiple FSP passes was investigated on the SiC particle distribution, processed zone dimensions, and microhardness of fabricated composites. The rotational speed, traverse speed, and tool tilt were kept constant and the numbers of passes were varied at 2, 4, 6, and 8. The particle distribution in processed zone was analyzed using OM and SEM, while microhardness were evaluated by Vickers indentation test. The results reveal that with increase in FSP passes there is increase in processed zone dimensions and elimination of defects such as agglomeration of particles and void. The microhardness of reinforced region was increased uniformly with increasing passes which is attributed to homogeneous distribution of reinforcement particles. The peak microhardness value of 81.9 Hv was obtained in sample which is processed with eight numbers of FSP passes. Processed zone indicates good bonding with the substrate and grain refinement.     

Tracking deforming objects using particle filtering for geometric active contours

Tracking deforming objects involves estimating the global motion of the object and its local deformations as a function of time. Tracking algorithms using Kalman filters or particle filters have been proposed for finite dimensional representations of shape, but these are dependent on the chosen parametrization and cannot handle changes in curve topology. Geometric active contours provide a framework which is parametrization independent and allow for changes in topology, in the present work, we formulate a particle filtering algorithm in the geometric active contour framework that can be used for tracking moving and deforming objects. To the best of our knowledge, this is the first attempt to implement an approximate particle filtering algorithm for tracking on a (theoretically) infinite dimensional state space.     

Development of a Sulfamic Acid-Based Chemical Formulation for Effective Cleaning of Modified 9Cr–1Mo Steel Steam Generator Tubes

A new sulfamic acid-based formulation is developed for the effective chemical cleaning of modified 9Cr–1Mo steel as a replacement for the conventional corrosive nitric acid (HNO3) and hydrofluoric acid (HF) mixture. The effect of sulfamic acid concentrations and inhibitor (2-mercaptobenzimidazole, MBI) on the metal loss during cleaning of modified 9Cr–1Mo steel was studied using weight loss and electrochemical impedance spectroscopic methods. The metal loss was found to increase with increase in acid concentration, but it was significantly lower with increasing inhibitor concentration, with an efficiency of > 90%. The corrosion rates of modified 9Cr–1Mo steel with 10% sulfamic acid + 2 mM MBI, 10% sulfamic acid without inhibitor and HNO3 + HF mixture were 1290, 6426, and 303,515 μm year−1 respectively. The optimal composition for efficient cleaning, with least base metal loss, was found to be 10% sulfamic acid + 2 mM MBI. Laser Raman spectroscopic (LRS) analysis of the corrosion products obtained during chemical cleaning process revealed that a protective chromium oxide film was formed during the cleaning with sulfamic acid + inhibitor as compared to iron oxide-based films with HNO3 + HF mixture and 10% sulfamic acid solutions.