Robust Prewhitening for ICA by Minimizing <Emphasis Type="Italic">β</Emphasis>-Divergence and Its Application to FastICA

Many estimation methods for independent component analysis (ICA) requires prewhitening of observed signals. This paper proposes a new method of prewhitening named β-prewhitening by minimizing the empirical β-divergence over the space of all the Gaussian distributions. The value of the tuning parameter β plays the key role in the performance of our current proposal. An attempt is made to propose an adaptive selection procedure for the tuning parameter β for this algorithm. At last, a measure of performance index is proposed for assessing prewhitening procedures. Simulation results show that β-prewhitening efficiently improves the performance over the standard prewhitening when outliers exist; it keeps equal performance otherwise. Performance of the proposed method is compared with the standard prewhitening by both FastICA and our proposed performance index.     

Measurements of neutron shielding properties of heavy concretes using a Cf-252 source

This investigation reports the experimental results of neutron transport and shielding properties of heavy concretes made from locally available ilmenite and magnetite sand. The experiment has been carried out with a ²⁵²Cf source and a BF₃ detector as a long counter. The thickness dependent removal cross section has been investigated and found to vary from 0.0936 cm⁻¹ at 5 cm to 0.0346 cm⁻¹ at 100 cm and 0.0990 cm⁻¹ at 5 cm to 0.0366 cm⁻¹ at 100 cm for ilmenite and magnetite concretes respectively. The results illustrate the effectiveness of ilmenite and magnetite heavy concretes so far as their sheilding properties are concerned. These materials may be used as a neutron shield in reactors, accelerators and neutron sources.     

MRCS: multi-radii circular signature based feature descriptor for hand gesture recognition

Multimedia Tools and Applications - Deaf and hearing-impaired persons communicate by means of signs and gestures. In course of time, this form of communication has evolved as natural languages with...     

An X-Ray Diffraction,Fourier-Transform Infrared Spectroscopy,and Scanning Electron Microscopy/Energy-Dispersive Spectroscopic Investigation of the Effect of Sodium Lignosulfonate Superplasticizer on the Hydration of Portland Cement Type V

This study investigated the effects of a common superplasticizer, ligno-sulfonate, on the hydration of Portland cement Type V. Samples of plain cement and superplasticizer-treated cement have been examined by x-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive spectroscopy. Lignosulfonate has been observed to retard the hydration of cement through specific surface chemical reactions which involve Ca²⁺ ions in pore solution. The admixture has been found to retard the formation of Ca(OH)₂ and stabilize ettringite [Ca₆(Al₂2O₆)(SO₄)₃.32H₂O]. The inhibition of the rate of conversion of ettringite to monosulfate [Ca₄Al₂(OH)₁₂.SO₄.6H₂O] is attributed to charge-controlled reactions caused by large quantities of Ca²⁺ ions from initial hydration reactions. Leaching of the admixture doped cement by water-removed lignosulfonate and caused complete hydration of cement. A charge-controlled-reaction model involving the Ca²⁺ ions is proposed to explain the role of the admixtures during hydration of cement.     

Synthesis and characterization of polycarbonates containing terminal and chain interior siloxane

Silicone polycarbonates having polydimethyl siloxane (PDMS) and heptamethyl trisiloxane (HMTS) were synthesized by the interfacial polymerization. Instead of common chain terminator p-tert-butyl phenol (PTBP), eugenol capped HMTS, and PDMS were used. PDMS was also attached into the chain interior of the polymer in different molar ratios. PDMS and HMTS were capped with eugenol through the hydrosilylation reaction using Karstedt’s catalyst. Both monohydroxy and dihydroxy terminated eugenosiloxanes were synthesized in order to use as chain terminator and interior subunit of polymer, respectively. Structural characterization and the study of the properties, such as thermal behavior, thermooxidative stability, surface morphology, wettability of the synthesized polymers were investigated. Flexibility and wettability of the synthesized polymers increases with increasing of silicone content. Polymers showed satisfactory thermo oxidative stability and transparency as good as bisphenol-A-polycarbonate.     

Identification of metal cations, metal complexes, and anions by electrospray mass spectrometry in the negative ion mode

Pneumatically assisted electrospray mass spectrometry (ES-MS) is used in the negative ion mode for aqueous metal (M) solutions in an excess of hydrochloric or nitric acid, where the major anion X = Cl- or NO3-. A collision energy of approximately 20 eV removes anion-solvent clusters for most elements and leaves negative complex ions of the general form (Mn+Xn+1)-. Complexation with anions prevents charge reduction reactions at least to n = 3, even in cases where the third ionization energy of M greatly exceeds the first ionization energy of the solvent. These negative ions thus preserve the charge state of the metal cation from the solution and allow identification of both cations and anions in a single set of electrospray conditions. Cations such as Fe3+ or Cu2+ that have a lower oxidation state in solution produce a distribution of negative ions, each with a single negative charge overall; e.g., an Fe3+ solution produces both Fe(III)X4- and Fe(III)X3-. This distribution of FeIII and FeII species is attributed to electrochemical reduction of Fe3+ at the negatively charged ES needle. "Native" anions such as perrhenate or molybdate produce singly charged analogues such as ReO4- or HMoO4-. Metal-EDTA complexes are seen as M(III)Y- or M(II)HY-. The sensitivity for these "native" anions is suppressed by competition with the excess chloride or nitrate used to produce the metal-containing complex ions.     

An FTIR, SEM and EDS investigation of solidification/ stabilization of chromium using portland cement Type V and Type IP

The characterization of chromium-doped ordinary portland cement (Cr-OPC) before and after leaching has been carried out using Fourier transform infrare     

Maximizing the production of acetone—butanol in an alginate bead fluidized bed reactor using clostridium acetobutylicum

Low volumetric solvent productivities are one of the characteristics of an acetone-butanol fermentation by C. acetobutylicum. A calcium alginate immobilized continuous culture was used in a novel gas-sparged reactor to strip the solvents from the aqueous phase and reduce their toxicity. A dilution rate of 0.07 h^?1 was found to give maximum solvent productivity at 0.58 g dm^?3 h^?1, although at 0.12 h^?1 the productivity was slightly lower. In order to increase glucose uptake by the culture, feed glucose concentrations were increased over time to attempt to acclimatize the culture. This resulted in a productivity as high as 0.72 g dm^?3 h^?1 although this production rate was found to be unstable.     

NOVEL CHEBYSHEV DISTRIBUTED CHIRPED PHOTONIC BANDGAP (PBG) STRUCTURES

A microstrip transmission line on a Chebyshev distributed chirped I-D photonic bandgap structure (PBGS) is proposed. Two different approaches are utilized to realize Chirped PBGS. Firstly, the inter-element distance of PBG elements is chirped with conventional chirping technique. Secondly, using Chebyshev distribution varies the inter-element distance. For both the cases, the amplitude is made non-uniform by varying the amplitudes in accordance with the co-efficient of Chebyshev distribution. It can be seen that the conventionally chirped PBGS having Chebyshev distribution in amplitude improves the over all performance. The inclusion of Chebyshev distribution in period calculation further improves the performance. It can be seen that the Chirped and non-uniform PBGS generates excellent bandgap performances in lower valued height of substrate that are superior to the performances available in the open literature.