Nanoscale characterization of gold nanoparticles created by in situ reduction at a polymeric surface

Transmission Electron Microscopy is used as a quantitative method to measure the shapes, sizes and volumes of gold nanoparticles created at a polymeric surface by three different in situ synthesis methods. The atomic number contrast (Z‐contrast) imaging technique reveals nanoparticles which are formed on the surface of the polymer. However, with certain reducing agents, the gold nanoparticles are additionally found up to 20 nm below the polymer surface. In addition, plan‐view high‐angle annular dark‐field scanning transmission electron microscopy images were statistically analyzed on one sample to measure the volume, height and effective diameter of the gold nanoparticles and their size distributions. Depth analysis from high‐angle annular dark‐field scanning transmission electron microscopy micrographs also gives information on the dominant shape of the nanoparticles.     

Study of Solubility Efficiency of Polycyclic Aromatic Hydrocarbons in Single Surfactant Systems

Water solubility enhancements of two polycyclic aromatic hydrocarbons i.e., naphthalene (Naph) and anthracene (Anth) in single surfactants system have been measured by UV–VIS-Spectrophotometer. The relationships between solubilizing capacity and their solubilization efficiency towards polycyclic aromatic hydrocarbons (PAH) have been quantified and discussed in terms of the molar solubilization ratio (MSR), the micelle-water partition coefficient (K _m) and standard free energy of solubilization (ΔG°_s). The micellar and surface properties of some cationic and anionic surfactants have been investigated by conductivity, surface tension and fluorescence measurements at 300 K. Above the CMC, maximum solubilization occurs in cationic surfactants where as the solubilization is least in the presence of anionic surfactants. The negative value of ΔG°_s shows spontaneity of the solubilization process. The MSR values are larger in naphthalene than anthracene (Naph > Anth). The present studies provide valuable information for the selection of surfactants for solubilizing water-insoluble compounds.     

3GPP LTE: The Future of Mobile Broadband

The mobile broadband technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with Orthogonal Frequency Division Multiple Access (OFDMA) based air interface technology. From technical perspective, fundamental goal of mobile broadband is to offer higher data rates with reduced latency. The third Generation Partnership Project (3GPP) presents the Long-Term Evolution (LTE) project in order to accommodate increasing mobile data usage and new multimedia applications. In the near future, with the recent progress made by technical specifications and vendor technology demonstrations LTE will emerge as successor to cellular systems as a broadband wireless solution. This paper provides an overview of 3GPP LTE including its history, features, technology, architecture and future. The technology components include OFDMA air-interface, Multiple-Input and Multiple-Output (MIMO) antenna technology and higher order modulation. The architecture includes Evolved Packet Core (EPC) and Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) components. This paper will concentrate to describe the main functions of the most important network elements. Also, the aim of this paper is to present the future potential of LTE which will make it an inevitable choice for wireless network operators around the globe.     

LONGITUDINAL DISPERSION IN RECTILINEAR FLOW OF DILUTE POLYMERIC LIQUIDS: LIKELY ROLE OF STRESS-INDUCED MIGRATION†

The likely role of stress-induced macromolecular migration in interpreting certain anomalous observations in longitudinal dispersion is discussed. In majority of the cases considered, the migration phenomenon affords an explanation for such behaviour, although in some instances, the operational regime for the dispersion process can itself explain the anomalies.

In those cases, where stress-induced migration could be a contributory factor, a semi-quantitative discussion based on our current understanding of the phenomenon is presented. Such a development, though rather simplistic in nature, enables (at least) a semi-quantitative elucidation of the pertinent variables which may affect the longitudinal dispersion processes involving polymeric media     

OPTIMAL STATE FEEDBACK CONTROL OF A CURRENT SOURCE INVERTER-FED INDUCTION MOTOR DRIVE USING A NEW ROTOR CURRENT OBSERVER

ABSTRACT

ABSTRACT The design, implementation and performance of a multivariable optimal state feedback controller for a Current Source Inverter-fed Induction Motor (CSI-IM) drive using a new reduced order observer to estimate rotor currents have been reported in this paper. A quadratic performance index together with a set of prescribed closed loop eigenvalues for placement are considered for application to a d-q axes state space linearized model of the drive to derive the control law - for achieving prescribed degree of stability in contrast to an earlier design with only pole-placement. The optimal control law derived is a function of all the states, the inaccessible states like d-q axes rotor currents being estimated by a new observer whose structure is simpler than that of one used in an earlier case. The controller-observer is implemented using an inexpensive microprocessor kit and the experimental results are presented along with the digital simulation results for the controlled drive to show its performance under step changes of load torque and references.     

Bilingual memory representation: A further test of dual coding theory.

Compared incidental recall for words coded as synonyms, translations, and copies in 28 Spanish-English, early and late onset bilingual undergraduates. 24 English-monolingual undergraduates recalled in draw, synonym, and copy conditions. Words in the synonym condition were recalled more than copied words by both groups of Ss, and bilingual Ss recalled imaged and translated words more often than synonyms. No differences were found between early and late onset bilinguals across words. It is argued that a dual coding view offers an explanation for these findings. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Beta-Galactosidase of Streptococcus cremoris H

Beta-galactosidase (Beta-D-galactosidegalactohydrolase, EC 3.2.1.23) of Streptococcus cremoris H was partially purified by ammonium sulfate fractionation. Only 10% of the protein was recovered as enzyme protein and more than 50% of the enzyme in the crude extract was lost. A 2.6-fold purification only was achieved. The enzyme was most active at 65°C and recorded an optimum pH at 7.0. Km and V_max with ortho-nitrophenyl beta-D galactopyranoside as the substrate were recorded as 0.384 mM and 12.6 μmoles/mg protein/min. Manganese ions activated the enzyme. The enzyme was strongly inhibited by Hg⁺⁺, Ca⁺⁺, Ni⁺⁺, and Ag⁺ as well as parachloromercuribenoate.