Noncorrosive separator materials for electric double layer capacitor

The paper evaluates noncorrosive and inexpensive materials, namely polypropylene sheet, fiberglass, and glass wool, as potential separator materials for electric double‐layer capacitor (EDLC) application. Using these materials as separators and the same activated carbon electrodes, properties of two‐electrode capacitors filled with aqueous sulfuric acid (H₂SO₄) were investigated by cyclic voltammetry (CV) as well as galvanostatic and electrochemical impedance spectroscopy (EIS) measurements. Performance comparison of the tested capacitors with an identical capacitor with conventional cellulose separator was also carried out. As a benchmark, the noncorrosive‐separator‐based capacitors demonstrate comparable power and energy densities to those of a cellulose separator, with the highest specific capacitance of 131 F/g and lowest equivalent series resistance of 13 Ω for the glass wool separator. Application of such noncorrosive separators may realize the utilization of high‐concentration aqueous electrolytes, leading to higher rating EDLCs at lower cost compared to organic‐solution‐based capacitors. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Functional characterization and evolutionary implication of the internal 157-amino-acid sequence of an exoinulinase from Penicillium sp. strain TN-88

An extracellular exoinulinase from the filamentous fungus Penicillium sp. strain TN-88 has a 14-fold higher specific activity of 743 U/mg toward inulin than its equivalent from the Aspergillus niger strain 12 and possesses an internal 157-amino-acid sequence whose corresponding region is absent in the A. niger enzyme. On the basis of sequence alignment, the internal region D' encoding the 157-amino-acid sequence in the Penicillium exoinulinase gene inuD cDNA was inserted into the site between the nucleotides 897 and 898 of the A. niger exoinulinase gene inuE cDNA. The resultant inuE::D' fusion was expressed in the methylotrophic yeast Pichia pastoris. The K(m) value of the secreted hybrid enzyme InuE::D' for inulin hydrolysis was about 1/15 that of the A. niger InuE, whereas its k(cat) value did not differ greatly from that of the InuE. These observations indicate that the Penicillium exoinulinase has evolved by the horizontal transfer and integration of a relevant DNA segment and that the internal sequence D' functions as an additional noncatalytic inulin-affinity region.     

Incentive‐rewarding mechanism to stimulate activities in social networking services

We have developed an incentive‐rewarding mechanism that stimulates activities in social networking services (SNSs), including content uploading and link establishment. We particularly focus on changing the reward assignment ratio based on the different risks users perceive when uploading content with different privacy settings: public‐open and friend‐limited. Learning‐based simulation allowed us to observe that SNS activity, which we measured as the amount of browsed content within a certain period, can be controlled by a rewarding assignment ratio. We then analyzed how the amount of uploaded content and the increase of established links affect SNS activity. Results suggested that the optimal reward assignment ratio to maximize SNS activity changes depending on the total amount of available reward resources. Copyright © 2011 John Wiley & Sons, Ltd.     

Thermal deformation measurement of the solder joints in electronic packages using electron moiré method

In this paper, electron moiré method is used to measure the thermal deformation of electronic packages. In order to observe the electron moiré fringe, a holographic grid was replicated on the cross section of the BGA type package at 150°C. This grid was fabricated on a glass plate using a moving point holographic system, and was replicated to measured area at high temperature. Under SEM, the holographic grid(specimen grid) and a programmed electron beam scan(master grid) interfere and form electron moiré patterns. The shear strain measurement technique using electron moiré method is described. Using the electron moiré method, the shear strains in the different solder joints were measured and analysed. Some useful results were obtained.     

Three-phase current-fed soft-switching PWM converter with auxiliarycommutation inductors and resonant snubber

A new three-phase current-fed soft-switching PWM converter is presented. This converter utilises two types of switching commutation scheme to improve the PWM current utilisation rate. It is shown by means of computer simulation that this converter has low THD and offers unity power factor correction     

An Analysis of Flow in a Centrifugal Impeller by FEM with k-ε Model

IntnMluctiouIn the passage of a centrifugal impeller, there is notonly a secondary flow toward a suchon-side from aPressure-side along a casing or a hub s~e but also aleakage flow through a clearance between a casings~e and a blade hp. The~, it is imPOI'tant tO clarifysuch a passage flow with regard to the design of acentrifugal turbomashinery with high efficiency.The impeller passage nows have been inveshgatedfrom the flow measurementS with a pressure Probe, ahot-wire anemometer and a LDV…     

Effects of the Hydroxylation Patterns and Degrees of Polymerization of Condensed Tannins on their Metal-Chelating Capacity

Abstract

We studied the effects of the hydroxylation patterns and the degrees of polymerization of condensed tannins on their metal-chelating capacity. These effects were evaluated by the relative stability of aluminium complexes with proanthocyanidin. The relative stability of aluminium complexes was determined qualitatively in methanol solution by the competition with the metallochromic reagent (chrome azurol S). A comparison of these capacities indicates the following results: 1) phenolic hydroxy groups in tannins are essential sites for the chelation with metal. 2) the sites of tannins interacting with metal ions are mainly o-dihydroxyphenyl groups in B-ring. 3) increasing degrees of polymerization of tannins tends to increase the relative stability of condensed tannin-aluminium chelate.     

Book reviews

Books reviewed in this article:
Travel Demand Management and Public Policy. Erik Ferguson.
Self-Organization and the City. Juval Portugali (in collaboration with A. Alafasi, I. Benenson, H. Haken, I. Omer). Foreword by Herman Haken.
Growth, Employment and Migration in Southeast Asia: Structural Change in the Greater Mekong Countries. Prema-chandra Athukorala, Chris Manning, Piyasiri Wickramasekara. Cheltenham, U.K.