The effect of water hardness on the solubilizing activity of linear alkylbenzene sulfonate

The behavior of linear alkylbenzene sulfonate in hard water has been studied by solubilization, transmittance and pH. Maximum solubilization is reported at specific water hardnesses on the basis of the change in the micellar properties of the detergent. The water hardness at maximum solubilization increases as the concentration of the detergent or of sodium tripolyphosphate (STPP), sodium nitrilo triacetic acid (NTA) or sodium ethylene diamine tetra acetic acid (EDTA) increases, while it decreases with an increase in the alkyl chain length of the detergent. A linear relationship between the detergent concentration and the water hardness at maximum solubilization or transmittance was found. It seems that the effect of STPP, NTA and EDTA on solubilization of anionic detergent was mainly due to water softening.     

Study of the flexural modulus of natural fiber/polypropylene composites by injection molding

Effect of fiber compression on flexural modulus of the natural fiber composites was examined. The kenaf, bagasse, and polypropylene were mixed into pellets, and composites were fabricated by injection molding. To predict flexural modulus of the composites, the Young's modulus of kenaf and bagasse fiber were measured. Using the obtained Young's modulus, the flexural modulus of the composites was predicted by Cox's model that incorporates the effect of fiber compression. It was found that those fibers with high Young's modulus were more compressed than that with low Young's modulus. Moreover, the distribution of fiber length and orientation in the composites were also investigated. To calculate the orientation factor for the prediction model, the distribution function of fiber orientation was determined to a triangular function. The flexural modulus of the composites increased with increase of volume fraction. The predicted values were in good agreement with the experimental values. Furthermore, it was revealed by SEM that the porous structure of the natural fibers was compressed. The fiber compression ratio (3.6) in bagasse was higher than that in kenaf (1.4) due to the difference in porous structure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 911–917, 2006     

In-Situ Coating of Zeolite Na-A on Al2O3-SiO2 Glass Fibers

In-situ coating of zeolite Na-A crystals on Al₂O₃-SiO₂ glass fibers was investigated by a low temperature chemical process. The glass fibers were reacted with various concentrations of NaOH solutions at 60–110°C for various times. The surface of glass fibers was first leached by the solution but crystals of zeolite Na-A precipitated on the glass fibers after a certain reaction time because the concentrations of Si and Al components in the solution increased by dissolution of the glass fibers. The precipitated zeolite was identified to be Na-A type but nosean-cancrinite-type phase and/or hydroxysodalite coexisted with zeolite Na-A at longer reaction times. With higher concentration of NaOH solution, the formation rate of zeolite Na-A was faster, the formation temperature was lower and the grain size was smaller ca. 2–3 m. Dense zeolite Na-A coatings were produced when the glass fibers were reacted in 4 M NaOH solution at 60°C for 18 h. The amount of zeolite Na-A formed on the fibers was about 20 mass%.     

Shape optimization of continua using NURBS as basis functions

The present paper introduces a numerical solution to shape optimization problems of domains in which boundary value problems of partial differential equations are defined. In the present paper, the finite element method using NURBS as basis functions in the Galerkin method is applied to solve the boundary value problems and to solve a reshaping problem generated by the H1 gradient method for shape optimization, which has been developed as a general solution to shape optimization problems. Numerical examples of linear elastic continua illustrate that this solution works as well as using the conventional finite element method.     

Construction and development of a time-resolved x-ray magnetic circular dichroism-photoelectron emission microscopy system using femtosecond laser pulses at BL25SU SPring-8

A femtosecond pulsed laser system has been installed at the BL25SU soft x-ray beamline at SPring-8 for time-resolved pump-probe experiments with synchronization of the laser pulses to the circularly polarized x-ray pulses. There are four different apparatuses situated at the beamline; for photoemission spectroscopy, two-dimensional display photoelectron diffraction, x-ray magnetic circular dichroism (XMCD) with electromagnetic coils, and photoelectron emission microscopy (PEEM). All four can be used for time-resolved experiments, and preliminary investigations have been carried out using the PEEM apparatus to observe magnetization dynamics in combination with XMCD. In this article, we describe the details of the stroboscopic pump-probe XMCD-PEEM experiment, and present preliminary data. The repetition rate of the laser pulses is set using a pulse selector to match the single bunches of SPring-8's hybrid filling pattern, which consists of several single bunches and a continuous bunch train. Electrons ejected during the bunch train, which do not provide time-resolved signal, are eliminated by periodically reducing the channel plate voltage using a custom-built power supply. The pulsed laser is used to create 300 ps long magnetic field pulses, which cause magnetic excitations in micron-sized magnetic elements which contain magnetic vortex structures. The observed frequency of the motion is consistent with previously reported observations and simulations.     

Local stresses at the intersection of cross-beam flange with box-girder web

Local stresses at the intersection of a top flange of a cross beam with a box-girder web are investigated analytically and experimentally. Finite element analyses of a T-shaped welded joint and a loading test of a cantilever beam of acrylic material reveal that a local stress which is different from the one caused by the stress concentrations at a weld toe is developed at the intersection. Finite element analyses of an I-section beam show that the restraint of the vertical deformation of the cross beam at the box-girder web induces the local stress. It is pointed out that the local stress must be considered in fatigue design. A method of determining the local stress is proposed.     

Inhibitory effect of chlorophyll c2 from brown algae,Sargassum horneri,on degranulation of RBL-2H3 cells

The anti-allergic effect of alcohol extracts from edible seaweeds was evaluated by the degranulation of a rat basophilic leukemia cell line (RBL-2H3). Extracts prepared from the brown algae Sargassum horneri, Ecklonia cava and Ecklonia kurome, inhibited the degranulation of RBL-2H3 cells, whereas those from green algae and red algae did not. The active substance in S. horneri was purified and identified as chlorophyll c2, a major pigment in brown algae. The purified chlorophyll c2 preparation also suppressed the degranulation of RBL-2H3 cells. In contrast, chlorophyll a and b did not affect cell degranulation. Therefore, chlorophyll c2 from brown algae might be useful for the prevention or mitigation of allergic symptoms.     

Performance improvement of induction motor speed sensor‐less vector control system using an adaptive observer with an estimated flux feedback in low‐speed range

Because of various errors caused by the dead time of an inverter, temperature variation of resistances, and so on, speed estimation error is inevitable in speed sensor‐less vector control of an induction motor. In particular, the speed control loop becomes unstable at near‐zero frequencies. In order to solve these problems, this paper proposes a novel design of an adaptive observer for speed estimation. By adding a feedback loop of the error between the estimated flux and the flux command, the sensitivity of speed estimation and primary resistance identification is improved. The proposed system is analyzed and appropriate feedback gains are derived. Experimental results showed good performance in the low‐speed range. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(3): 33–46, 2009; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20909     

An Investigation of Microstructure and Phase Transformation Behavior of Cu40Zn-1.0 wt.% Ti Brass Via Powder Metallurgy

The effects of Ti addition on phase transformation, precipitation behavior, and microhardness response of Cu40Zn brass were investigated at elevated heat treatment (HT) temperatures using the powder metallurgy method. The volume fraction of the α phase increased with the elevated temperatures, which showed an equal value as that of the β phase at 400 °C, and reached a maximum value of 55.9% at 500 °C. The solid solubility of Ti in Cu40Zn brass matrix decreased as the HT temperature increased. Supersaturated Ti showed high chemical potential for precipitates' reaction in Cu40Zn brass. Lower HT temperature retained higher Ti solid solubility and fine precipitates. The precipitates presented in form of Cu₂TiZn intermetallic compound, distributing uniformly in brass matrix which suppressed the phase and grain growth. After HT at elevated temperature, the precipitates coalesced, grew coarser, and segregated at the primary particle boundaries. The microhardness of the BS40-1.0Ti compact was primarily not only dependent on the solid solubility of Ti, but also dependent on the phase volume fraction of the α and β phases.