Extraction of yarn positional information from three-dimensional CT image of textile fabric using a yarn model for its structure analysis

This paper proposes a novel method for analyzing a textile fabric structure to extract positional information regarding each yarn using three-dimensional X-ray computed tomography (3D CT) image. Positional relationship among the yarns can be reconstructed using the extracted yarn positional information. In this paper, a sequence of points on the center line of each yarn of the sample is defined as the yarn positional information, since the sequence can be regarded as the representative position of the yarn. The sequence is extracted by tracing the yarn. The yarn is traced by estimating the yarn center and direction and correlating the yarn part of the 3D CT image with a 3D yarn model, which is moved along the estimated yarn direction. The trajectory of the center of the yarn model corresponds to the positional information of the yarn. The application of the proposed method is shown by experimentally applying the proposed method to a 3D CT image of a double-layered woven fabric. Furthermore, the experimental results for a plain knitted fabric show that this method can be applied to even knitted fabrics.     

Catalytic Methoxycarbonylation of Aromatic Diamines with Dimethyl Carbonate to Their Dicarbamates Using Zinc Acetate

The methoxycarbonylation of 2,4-toluene diamine and 4,4-diphenylmethane diamine with dimethyl carbonate to the corresponding dicarbamates using zinc acetate was carried out at 453 K. Zn(OAc)₂, prepared by evacuating Zn(OAc)₂2H₂O at 383 K for 2 h, yields dimethyltoluene-2,4-dicarbamate in 96% yield in 2 h, while Zn(OAc)₂2H₂O yields dimethyl-4,4-methylenediphenyldicarbamate in 98% yield at 453 K in 2 h.The structure of methyl 3-amino-4-methyl phenyl carbamate, which is one of the intermediates for the reaction of 2,4-toluene diamine with dimethyl carbonate into dimethyltoluene-2,4-dicarbamate, has been determined by measuring the NOE spectrum of ¹H NMR.     

Development of bio-based hybrid resin,from natural lacquer

Preparation and structure analysis of a bio-based hybrid material composed of natural lacquer, epoxy, and organic silane compounds were investigated using liquid and solid-state nuclear magnetic resonance. The good composition of additives in the hybrid was determined by the drying, hardness, and resin-molding properties. Although natural lacquer alone cannot form thick resins, this bio-based hybrid material showed good resin formation at room temperature without thermal treatment. This result could be based on the enhancement of curing by the sol–gel reaction between natural lacquer and the organic silane compound, and a crosslink reaction between organic silane and epoxy groups. At the same time, oxidative polymerization at the unsaturated side chains in the urushiol was enhanced by the sol–gel reaction because the catechol hydroxyl groups, which have an antioxidative property, reacted with the organic silane. In addition, this bio-based resin possesses a thermoset property because curing of the hybrid was improved by thermal treatment. Based on the structure analyses, the sol–gel reaction between urushiol and organic silane compound proceeded immediately, indicating the high reactivity of this sol–gel reaction. On the other hand, the reaction between bisphenol A-type epoxy resin and the organic silane seems to progress slowly after the epoxy ring opening. In addition, a sol–gel reaction occurred between the amine group in the organic silane and the hydroxyl group formed after the crosslink reaction of the epoxy group. These results suggested that the improvement in drying and molding properties of the hybrid was based on the chemical reactions among all components (i.e., natural lacquer, epoxy, and organic silane).     

Synthesis of polyvinyl alcohol stereoblock copolymer via the combination of living cationic polymerization and RAFT/MADIX polymerization using xanthate with vinyl ether moiety

Different types of novel xanthates containing a vinyl ether moiety, S-benzyl O-2-(vinyloxy)ethyl carbonodithioate (Xanthate 1) and S-1-(ethoxycarbonyl)ethyl O-2-(vinyloxy)ethyl carbonodithioate (Xanthate 2) were synthesized. In particular, the Xanthate 2 enabled to design polyvinyl alcohol (PVA) stereoblock copolymer via the combination of living cationic vinyl polymerization and RAFT/MADIX polymerization. For cationic polymerization of isobutyl vinyl ether (IBVE) and tert-butyl vinyl ether (TBVE), the polymerizations were conducted under Xanthate 1-HCl adduct/SnCl₄ and Xanthate 1 or 2-CF₃COOH adduct/EtAlCl₂ initiating system in the presence of ethyl acetate. Both systems proceeded in living polymerization fashion because the calculated M_n of both poly(IBVE) and poly(TBVE) matches with the M_n polymerized assuming that one polymer chain is formed per one molecule of the Xanthate 1 or 2. The resulting poly(TBVE) had a high number average α-end functionality as determined by MALDI-TOF-MS spectrometry. Xanthate 2 is more efficient for the following RAFT/MADIX polymerization of vinyl acetate (VAc). The RAFT/MADIX polymerization of vinyl acetate (VAc) using azobis(isobutyronitrile) (AIBN) at 60 °C was conducted using either poly(IBVE) or poly(TBVE) macro-CTA. The poly(TBVE) macro-CTAs synthesized from the Xanthate 2 were able to polymerize VAc smoothly via RAFT/MADIX polymerization, to prepare well-defined diblock copolymer, poly(TBVE)-b-poly(VAc). The resulting block copolymer was then hydrolyzed using KOH in methanol and followed by acid hydrolysis using HBr gas bubbling. The resulting polymer is inherently stereoblock like copolymer, isotactic rich PVA-b-atactic PVA (iPVA-b-aPVA). From the DSC measurement, the iPVA-b-aPVA has one glass transition at 69.5 °C and two melting points according to iPVA and aPVA at 237.9 and 198.1 °C, respectively. Thus, it can be suggested that the obtained PVA has two different geometries by the combination of living cationic polymerization and RAFT/MADIX polymerization.     

Pore structure of aluminas derived from the alkyl derivatives of boehmite

The alkyl derivatives of boehmite (alkoxyalumoxanes; AlO(OH)_1?x (OR) _x ) were synthesized by the reaction of aluminum triisopropoxide in straight-chain primary alcohols at 300 °C for 2 h in an autoclave. In the present work, pore structures of aluminas obtained by calcination of the alkyl derivatives of boehmite were examined. The alumina obtained from the ethyl derivative of boehmite had a broad pore-size distribution, while the pore-size of the alumina obtained from the dodecyl derivative of boehmite distributed in a narrow range in the mesopore region. The mode pore diameter of the latter alumina increased with the increase in calcination temperature (as-syn., 39 Å; 600 °C, 54 Å; 800 °C, 58 Å; 1000 °C, 68 Å), but narrow pore-size distribution was maintained even after calcination at high temperatures.     

Novel Processing for Mesoporous Silica Films with One-Dimensional Through Channels Normal to the Substrate Surface

Mesoporous silica films with one-dimensional through channels perpendicular to the substrate surface have been fabricated successfully by a novel process, which was a combination of eutectic decomposition of amorphous films and subsequent chemical etching. In the case of the Fe–Si–O system, amorphous precursor films annealed under oxidizing conditions were decomposed to a regular array of needlelike hematite (Fe₂O₃) crystals with a diameter of ∼4 nm surrounded by an amorphous silica matrix. Then, hematite crystals were preferentially removed by chemical etching. The pore surface areas of the remaining mesoporous SiO₂ films were found to be more than 1000 m²/g by an isothermal N₂ gas adsorption and desorption measurement.     

Dehydrogenation and hydrogenation activity of palladium-tin-silica and nickel-tin-silica

The dehydrogenation of cyclohexanone, cyclohexylamine, cyclohexane, and 2-propanol and the hydrogenation of ethylene on palladium-tin-silica and the hydrogenation of benzene on nickel-tin-silica were studied. With nickel-silica and nickel-tin-silica, the deposition of carbonaceous materials was studied kinetically. The X-ray photoelectron spectra of palladiumtin and nickel-tin were observed. The catalytic activities of both of the catalyst systems changed in similar ways with the change of the $\text{Pd}\text{Sn}$ and $\text{Ni}\text{Sn}$ ratios (atomic) of the catalysts. The dehydrogenation activity increased to a maximum and then decreased, with a decrease in the $\text{Pd}\text{Sn}$ and $\text{Ni}\text{Sn}$ ratios. The hydrogenation activity of the tin-containing catalysts was much lower than that of the tin-free catalysts. Carbonaceous materials were observed to be deposited more easily on the nickel-silica than on the nickel-tin-silica. The palladium-4d and nickel-3d band peaks of the alloy systems obtained by X-ray photoelectron spectroscopy were observed to shift to higher binding energies as the $\text{Pd}\text{Sn}$ and $\text{Ni}\text{Sn}$ ratios decreased. From the amount of carbon monoxide adsorbed, the surface concentration of palladium and that of nickel on the catalysts were suggested to be the minor determining factor of the catalytic activity studied here. It is concluded that tin is not just a diluent for the active metal but is an effective component to weaken the adsorption bond.     

A Stochastic Approach to the Detection of Receptive Fields in the Visual System

A statistical approach is developed for the detection of receptive fields of cells in the visual system. A spatiotemporal random pattern of light, composed of successive frame patterns, is used as a stimulation signal. A frame consists of N2 square elements: N rows and N columns. The brightness of each element is independent to one another and takes "light" or "dark" state. Shaped random patterns are defined in the spatiotemporal random pattern, and a list indicating the presence and absence of a defined feature pattern is made from the spatiotemporal random pattern. The receptive field is described in terms of the spatial response function based on a cross correlation between cell's reponse and feature signal (feature list). Consideration is given to feature parameters affecting on results.