Enhancing water flux through semipermeable polybenzimidazole membranes by adding surfactant‐treated CNTs

In this study, surfactant‐treated carbon nanotubes (CNTs) were incorporated into polybenzimidazole (PBI) matrix to prepare the PBI/CNT composite membranes with CNT content in the range of 0 to 15 wt %. The composite membranes were fabricated by spin‐coating. The membrane morphology, mechanical property, and water and salt transport properties were investigated to characterize the additive effect of CNTs. The tensile strength of all the PBI/CNT composite membranes was lower than that of pristine PBI membrane, indicating the weak interaction between CNT and PBI. In addition, water flux increased without reducing the salt rejection when CNTs were homogeneously dispersed in the PBI matrix at a less than 7.5 wt % content. On the other hand, at 10 wt % and higher CNT content, submicro‐scaled cellular structure was formed, and both the water flux and salt rejection decreased. The well‐dispersed CNTs in the PBI matrix via weak interaction preferentially improve the water permeability by 1.7 times without depressing the salt rejection. The incorporation of well‐dispersed CNTs in polymer matrix provides a promising and facile option for improvement in the water transport properties through the polymeric semipermeable membranes with intrinsically low water permeability such as PBI. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45875.     

Suppression of deicing salt corrosion of weathering steel bridges by washing

To elucidate the influences of deicing salts and high pressure (2-4 MPa) washing on the characteristics of the rust formed on weathering steel bridges, washing experiments have been carried out for three years. The rust was characterized by means of ion chromatography, X-ray diffraction and adsorption of N₂. The rust thickness was measured, and also the rust weight per unit area of the steel surface was measured. It was found that water-soluble chloride accelerated the rate of corrosion because the rust particles grow by the chloride ions and micro-pore structure of the rust appeared by the chloride ions. Washing with water suppressed corrosion owing to the disappearance of chloride ions.     

Substitution effects on the electronic anomaly and superconductivity in La2−xBaxCuO4 and La2−xSrxCuO4 with x ∼ 1/8

The effects of substitution of Y or Bi on the low-temperature structural phase transition, electronic anomaly and superconductivity have been studied in La_2-y-xY_yBa_xCuO La_2-y-xBi_yBa_xCuO₄ and La_1.9-y-xTb_0.1Bi_ySr_xCuO₄ with x = 1/8. Moreover, an electronic anomaly, which is analogous to those observed in La_2–xBa_xCuO₄ and La_1.6-xNd_0.4Sr_xCuO₄ with x 1/8, has been found below about 60 K in the thermoelectric power measurements for the Zn-substituted La_2–xSr_xCu_1–yZn_yO₄ with x 0.115 and y = 0.01 – 0.02. These experimental results support the conclusions by Tranquada et al. that static order of the stripe correlations of holes and spins, owing to pinning by the low-temperature structure or impurities (Zn in this case), is the origin of the electronic anomaly, leading to the suppression of superconductivity.     

A brief review of affordance in robotic manipulation research

Abstract

This paper presents a brief review of affordance research in robotics, with special concentrations on its applications in grasping and manipulation of objects. The concept of affordance could be a key to realize human-like advanced manipulation intelligence. First, we discuss the concept of affordance while associating with the applications in robotics. Then, we intensively explore the studies that utilize affordance for robotic manipulation applications, such as object recognition, grasping, and object manipulation including tool-use. They obtain and use affordance by several ways like learning from human, using simulation, and real-world execution. Moreover, we show our current work, which is a cloud database for advanced manipulation intelligence. The database accumulates various data related to manipulation task execution and will be an open platform to leverage various affordance techniques.     

Demonstration of the cold sintering process study for the densification and grain growth of ZnO ceramics

With the cold sintering process (CSP), it was found that adding acetic acid to an aqueous solution dramatically changed both the densities and the grain microstructures of the ZnO ceramics. Bulk densities >90% theoretical were realized below 100°C, and the average conductivity of CSP samples at around 300°C was similar to samples conventionally sintered at 1400°C. Frequently, ZnO is also used as a model ceramic system for fundamental studies for sintering. By the same procedure as the grain growth of the conventional sintering, the kinetic grain growth exponent of the CSP samples was determined as N=3, and the calculated activated energy of grain growth was 43 kJ/mol, which is much lower than that reported using conventional sintering. The evidence for grain growth under the CSP is important as it indicates that there is a genuine sintering process being activated at these low temperatures and it is beyond a pressurized densification process.     

Effect of γ-ray Irradiation on the Wettability of TiO2 Single Crystals

The contact angles of the water droplets on TiO₂ single crystal surfaces decreased and became superhydrophilic state by γ-ray irradiation. It was found that these behaviors were dependent on γ-ray irradiation atmosphere, i.e., in air and in N₂ atmosphere (r. h.; 30%) as well as crystal faces of TiO₂ single crystals, i.e., TiO₂ (100) and (110) surfaces. It was also found from the results of UV–Vis and ESR measurements that γ-ray irradiation under N₂ atmosphere led to the oxygen vacancies and associated Ti³⁺, regardless of the presence of gaseous water. Moreover, it was suggested that the organic molecules adsorbed on TiO₂ single crystal surfaces decomposed by γ-ray irradiation.     

Long-chain carboxylic acids containing ether linkage III. The antibacterial and antifungal activities of the amine salts of someB-alkoxypropionic acids

Octylamine, dodecylamine, octadecylamine and triethanolamine salts ofβ-dodecyloxy- andβ-tetradecyloxypropionic acids, without or with one and with two oxyethylene groups between the alkoxy group and the propionic acid group, were prepared and examined as the growth inhibiting agents againstStaphylococcus aureus andPenicillium. Some of them were also tested againstTrichophyton asteroides, T. interdigitale, T. granulosus, Epidermophyton floccosum andMicrosporum canis. The effects of the alkyloxy, oxyethylene and amine groups on antibacterial and antifungal activities were determined. The dodecyl radical was more potent than the tetradecyloxy radical. The enhancing effect of the oxyethylene group was obscure in the amine salts. The most effective amine was dodecylamine and its salt ofβ-dodecyloxypropionic acid showed almost the same effectiveness as that of its mercury salt againstTrichophyton. As for the soluble amine salts, it was confirmed that their surface activities had nothing to do with their antibacterial and fungicidal powers.     

Numerical simulation of the flow in an extensional flow mixer. Effect of fluid elasticity on the flow

We discuss the viscoelastic flow of the matrix fluid in an Extensional Flow Mixer (EFM) obtained by a numerical simulation. The effect of the fluid viscoelasticity on the flow state in an EFM was considered by the comparison of the flow states of the purely viscous fluid and the viscoelastic fluid. The mixing performance of the EFM is also considered. The Phan‐Thien Tanner model was used as the constitutive equation of the viscoelastic fluid and the Carreau model was used as that of the purely viscous fluid. Results obtained are as follows: (1) Stagnation flows occur in the converging‐diverging plates (c‐d plates) in the case of viscoelastic fluid. The size of stagnation flow region becomes large when the fluid has a strain‐thickening elongational viscosity. (2) The absolute value of the extensional strain and the pressure drop in the c‐d region increase with fluid elasticity. Meanwhile, the residence time in the c‐d region decreases with that. (3) There is no stagnation region in the c‐d plates for a purely viscous fluid. The stagnation flow has an effect on the estimation value of EFM's performance. The prediction by the purely viscous fluid is not useful for the flow in an EFM because of extremely low accuracy.     

Determining double-bond positions in monoenoic 2-hydroxy fatty acids of glucosylceramides by gas chromatography-mass spectrometry

We applied a gas chromatography-mass spectrometry (GC-MS) method using dimethyl disulfide (DMDS) adducts and were able to determine the double-bond positions in monounsaturated 2-hydroxy fatty acids (2-HFA). 2-HFA methyl esters, prepared from the hydrolysate ofArabidopsis thaliana leaf glucosylceramides, were acetylated and methylthiolated. GC-MS analysis of the resulting DMDS adducts showed simple mass spectra with recognizable molecular ions and a series of key fragment ions indicating the original double-bond positions in the aliphatic chain. Based on this GC-MS elucidation, we confirmed thatArabidopsis leaf glucosylceramides have C₂₂, C₂₃, C₂₄, C₂₅, and C₂₆ chain length 2-HFA with monounsaturation, and all their double bonds are placed at the n−9 position. This procedure is simple, time efficient, and highly sensitive.     

Polymer optical fiber for near infrared use

Using the empirical simulation that we developed to estimate loss spectra of amorphous polymers, we predicted the intrinsic loss spectrum of fluorine-containing polyarylate (FPAr) that should have a small attenuation loss in the near infrared region. Loss of FPAr is smaller than that of poly (methyl methacrylate), which is a typical optical polymer used as a core material in polymer optical fiber (POF), above 720 nm. FPAr was synthesized by phase transfer catalyzed polycondensation of 2,2-bis (4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane with isophthaloyl dichloride. Its glass-transition temperature (T_g) by DSC is 163°C. This indicates that FPAr has higher heat resistance than polycarbonate (PC) by about 10°C. A film of 100μm thick has over 85% transmittance from 330 to 900 nm. Values from a tension test are similar to those of PC. As a result, FPAr is expected to be a good core polymer for POF, because of its high T_g, good transparency, and good flexibility. Next, the POF made of FPAr was fabricated by a melt-flow spinning method. It had larger attenuation loss than predicted. The difference from the simulation was extrinsic loss caused by the fabricating process. Therefore, when a more suitable fabricating process is developed, loss of FPAr-POF can be decreased, so that it will be applicable to optical communications in the near infrared region. © 1993 John Wiley & Sons, Inc.