Influence of dialkyl ethers on the surface properties of homogeneous nonionic surfactants

Influence of the trace amounts of the corresponding dialkylethers on the surface and colloidal properties of the pure polyoxyethylene alkyl ethers were studied. The dialkyl ether, undetected by gas liquid chromatography (GLC) was found by gel permeation chromatogram (GPC) as the corresponding impurity in homogeneous pure polyoxyethylene alkyl ether and confirmed using infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS). After removing the corresponding impurity in each surfactant with a GPC separation column, the minima in the surface tension curves disappeared completely. Adding the corresponding dialkyl ether to the pure surfactant produced the minima in the surface tension curves and large values for surface aging, cloud points were lowered more than for the pure surfactants and foam height and foam stability for the aqueous solutions decreased gradually.     

A liquid rate gyroscope using electro-conjugate fluid

We propose a novel liquid rate gyroscope using an electro-conjugate fluid (ECF). The electro-conjugate fluid is a dielectric fluid that works as a smart fluid, generating a powerful jet flow (ECF jet) when subjected to a high DC voltage. In this study, we introduce this functional fluid into gyroscopes. Although the sensing principle for angular rate is based on that of a conventional gas rate sensor, the proposed gyroscope has a much higher sensitivity because the density of the liquid is generally higher than that of a gas. In addition, the gyroscope is small in size because the ECF jet is generated only with a pair of tiny electrodes. In other words, the pumping part of the proposed gyroscope does not need mechanical moving parts, resulting in an ECF gyroscope more suitable for micro-applications than a gas rate sensor, which requires a pumping mechanism inside. We fabricated a prototype of the liquid rate gyroscope (40 mm × 60 mm × t7 mm) and confirmed its characteristics by experiments. The experimental results confirm the effectiveness of the proposed liquid rate gyroscope. The prototype has a scale factor of ?29 mV/(°/s) with an applied voltage of 4.5 kV, which is 2.2 times more sensitive than the conventional gas rate gyroscope.     

Solvolytic liquefaction of coals with a series of solvents

Solvolytic liquefaction of coals of different rank was studied with a variety of solvents at 370–390 °C under nitrogen in order to elucidate the role of solvent in coal liquefaction of this kind and to find a suitable solvent for the highest yields of liquefaction. The yield was found to depend strongly upon the nature of the coal as well as the solvent under these conditions. Pyrene and a SRC-BS pitch were excellent solvents for Miike coal, which was fusible with high fluidity at these temperatures. However, the former was less efficient for Itmann and Taiheiyō coals which were fusible at a higher temperature and non-fusible, respectively. The mechanism of solvolytic liquefaction is discussed, including nature of coal and solvent at reaction temperatures, in order to understand the properties required for high yields with non-fusible coals in solvolytic liquefaction. It is found that for liquefaction with a high yield if the coal is non-fusible, solvolytic reaction should take place between solvent and coal, so giving a liquid phase of low viscosity at the reaction temperature. The solvolytic reaction may be one of hydrogen transfer when SRC-BS is used as the solvent.     

Effect of the plate thermal resistance on the heat transfer performance of a corrugated thin plate heat exchanger

Two‐dimensional conjugate conduction/convection numerical simulations were carried out for flow and thermal fields in a unit model of a counter‐flow‐type corrugated thin plate heat exchanger core. The effects of the thermal resistance of the solid plate, namely the variation of the plate thickness and the difference of the plate material, on the heat exchanger performance were examined in the Reynolds number range of 100<Re<400. Higher temperature effectiveness was obtained for a thicker plate at any Reynolds number, which was a unique feature of corrugated thin plate geometry. Detailed discussions on the thermal fields revealed that restricting the heat conduction along the plate by making the plate thinner or choosing a low thermal conductivity material causes a larger plate temperature variation along the plate, and, consequently, a smaller amount of thermal energy exchanged between two fluids. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(3): 209–223, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20110     

Pressure sensing by electrical admittance measurement of a comb‐drive actuator

This paper describes a micromachined pressure sensor that senses pressure not by a diaphragm structure but by a resonantly vibrating comb‐drive actuator. The electrical admittance of the comb‐drive actuator was directly measured using a lock‐in amplifier, and its pressure dependence was examined. From the experiment, it was found that the resonant frequency of the comb‐drive actuator gradually drops as the pressure increases. The sensitivity of the comb‐drive actuator as a pressure sensor was 0.34 Hz/MPa at atmospheric pressure and 0.1 Hz/MPa at 0.4 MPa absolute pressure. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Association of nonionic polymer with hydrocarbon/fluorocarbon surfactant in aqueous solution

The interaction between a nonionic polymer and a hydrocarbon or fluorocarbon surfactant has been investigated by means of surface tension, viscosity, electroconductivity, fluorescence probing, solubilization of a waterinsoluble dye, and electron spin resonance (ESR). The systems studied consisted of polyvinylpyrrolidone (PVP) with lithium dodecyl sulfate (LiDS) or lithium perfluorooctane sulfonate (LiFOS). Surface tension measurements indicated that formation of PVP-surfactant complex is more favorable in the PVP-LiFOS system than in the PVP-LiDS system, and that the adsorbed amount of LiFOS is less than that of LiDS, although the CMCs of the surfactants are almost the same. In the PVP-LiFOS system, the relative viscosity and the solubilized amount of a water-insoluble dye showed a maximum at a certain concentration of LiFOS in the region between two transitions observed in the surface tension, where also a change in the slope of the electroconductivity is observed. These results indicate that shielding of effective charge of the PVP-LiFOS complex causes a conformational change of PVP wrapped around the aggregate of LiFOS with an increase of free surfactant in the bulk phase. The conformational change can be correlated with microenvironmental properties of PVP-surfactant complexes. The microviscosity estimated with ESR indicated that the headgroups of LiFOS adsorbed on PVP are less tightly packed than those of LiFOS micelles, while an opposite result was obtained in the PVP-LiDS system. In particular, the marked high viscosity at a low concentration of LiFOS in the PVP-LiFOS system can probably be attributed to rigidity of the fluorocarbon chain of LiFOS.     

Polycondensation of Chiral 3,4-Dihydro-N-Substituted Succinimide and Phthalic Acid Dichloride

Summary Polycondensations of (3R,4R)-3,4-dihydro-N-substituted succinimide (DHRSI) and phthaloyl dichloride (χ-PA) were carried out to obtain optically active polyesters ([α]_D = −ll.0° to +206.1°). The GPC curve of poly(DHPhSI/o-PA) by polarimetric detector (α_Hg) showed dextro rotation at a low molecular weight fraction and levo rotation at a high molecular weight fraction. Optical activities were attributed to configurational and/or conformational chirality. Received: 3 February 2003/Revised version: 19 March 2003/Acccpted: 19 March 2003 Correspondence to Tsutomu Oishi     

Preparation of colloidal silver using various reductants in the presence of copolymers of vinyl alcohol-N-vinyl pyrrolidone

Colloidal silver was prepared using various reductants such as hydrazine, ascorbic acid, ribose, and hydrogen in aqueous solution in the presence of copolymers of vinyl alcohol-N-vinyl pyrrolidone. The average particle size of colloidal silver decreased with increasing amount of copolymers added. The reduction by hydrogen provided smaller silver particles compared with the other reductants. The stability of colloidal silver against AlCl₃ increased with increasing amount of copolymers added.     

Study on visual machine-learning on the omnidirectional transporting robot

We present a computer vision solution integrated to an omnidirectional transporting robot to perform the position tracking of multiple trays moving on its planar acrylic plate surface. The trays were designed to carry lightweight materials on top of their surface so that the mechanism could be implemented as an automated transporting system for applications that require the displacement of products and/or materials in any given space. One hurdle faced by the visual system for suitable detection was the partial occlusion of the image of a tray when placing arbitrary objects on its surface. Our strategy to overcome this challenge consisted on the implementation of machine learning algorithms, such as Support Vector Machines (SVM), using datasets of images containing trays with different occlusion patterns for fast object detection through rigorous training. The results of experimental tests validate the implementation of our proposal as a reliable approach for the object tracking of multiple trays on the robotic device, even under partial occlusion. We also studied the accuracy of the position measurements performed by our visual system with respect to the position measurements taken by the OPTITRACK motion capture system and evaluated the processing time per frame required by the software implementation.     

A Compact Furnace for Synchrotron Powder Diffraction Experiments up to 1800 K

A new electric furnace has been designed and fabricated for measurements of the high-resolution synchrotron radiation powder diffraction profiles from materials at high temperatures up to 1807 K in air, suitable for the multiple-detector system installed at the BL-4B₂ experimental station of the Photon Factory, Tsukuba, Japan. In the present study, at 1703 K in air, the whole powder pattern of National Institute of Standard and Technology ceria powder was step scanned at a step interval of 0.004° in 2θ, by the counting time of 1.5 s/step and with a monochromatized 1.205363(5) Å X-ray, in just 7 h. The full width at half-maximum of the 111 reflection of the ceria was narrow (0.0139°). The δ d / d resolution of the ceria ranged from 0.058% to 0.126% at 1703 K, where d and δ d are the lattice spacing and peak width, respectively. Precise unit-cell parameter 5.51259(1) Å and the atomic displacement parameters were refined by the Rietveld analysis of the powder data measured at 1703 K. An electron-density map of ceria at 1703 K was obtained by the maximum-entropy method.