Influence of dilution by polydimethylsiloxane on electrorheological effect of side-chain liquid crystalline polysiloxane

A liquid crystalline polysiloxane (LCP), having an ether bond in the spacer between its siloxane main chain and its mesogenic-group side chains, exhibited a very small electrorheological (ER) effect or increase in shear stress upon application of an electric field, but mixtures of the LCP and polydimethylsiloxane (PDMS) exhibited a sharply increasing ER effect with increasing PDMS content throughout the tested range of up to 0.5 of PDMS weight fraction. When phenyl-substituted PDMS (Ph-PDMS) at a weight fraction of 0.3 was used instead of PDMS, however, the ER effect decreased with increasing phenyl content and became nearly undetectable with Ph-PDMS having a phenyl content (ratio of substituted phenyl groups to initial methyl groups) of approximately 15%. DSC analyses showed that the ER effect of the LCP/PDMS mixtures occurred undiminished throughout a temperature range in which LCP itself is an isotropic liquid in the absence of an applied electric field and suggested that the LC structure of the LCP was maintained even when it was diluted with PDMS in weight fractions of 0.5 or higher, but disrupted when diluted by a 0.3 weight fraction of Ph-PDMS having a 15% phenyl content. Optical microscopic observation of the mixtures of the LCP with a 0.3 weight fraction of PDMS or Ph-PDMS (15% phenyl content) showed that both consisted of uniformly dispersed micron-sized droplets which became elongated in the direction of the applied electric field when it was applied alone but became smaller when both the electric field and shear were applied. These results suggest that the phase separation between the LCP and the dilution oil, as well as the existence and orientation of LC domains, is essential for the generation of a large ER effect. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1319–1328, 1997     

Surface grafting of poly(vinylamine) onto poly(ethylene) film by corona discharge‐induced grafting

Poly(vinylamine) (PVAm) was grafted on a poly(ethylene) (PE) film surface via the surface graft polymerization of N‐vinylformamide (NVF) and N‐vinylacetamide (NVA) and the subsequent hydrolysis of those grafted polymers. The surface was characterized by X‐ray photoelectron spectroscopy (XPS), contact angle, moisture absorption, and the leakage of electrostatic charge from the films. PNVF and PNVA were introduced onto the surface of the PE film successfully, in spite of the fact that the initiator for polymerization was a peroxide group. The grafted amounts of PNVF and PNVA were dependent on the grafting time. A PVAm‐grafted surface was obtained via the hydrolysis of the grafted PNVF. The grafted‐PNVA was not hydrolyzed under mild hydrolysis. The obtained PVAm‐grafted surface appeared to be useful for various applications, such as protein immobilization or chemical modification. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1583–1587, 1999     

Transformation algorithm from Ladder Diagram to SFC using temporal logic

The Ladder Diagram (LD) has been widely used in industry as a language for sequential control. However, the LD cannot represent sequential flows of control logic explicitly. This leads to difficulties for other engineers in understanding the control logic. To overcome this problem, the Sequential Function Chart (SFC) has been proposed. Because the SFC can represent sequential flow explicitly, it is expected to be used more widely. Since the LD has been widely used in the past, however, it is necessary to develop an algorithm for transformation from the LD to the SFC. In this paper, a technique to transform an LD to the corresponding SFC by using temporal logic is proposed. In the closed loop system which consists of the LD and the controlled plant, sequence information including parallel path divergences is extracted to develop the transformation algorithm. An example is presented to verify the feasibility of the proposed algorithm. © 1999 Scripta Technica, Electr Eng Jpn, 129(1): 74–81, 1999     

Acceleration radiosity solutions through the use of hemisphere-base formfactor calculation

In this paper, we propose a novel formfactor calculation algorithm for acceleration radiosity solutions in complex environments. Our basic algorithm is an improved version of Spencer's (S.N. Spencer, ‘The hemisphere radiosity method: a tale of two algorithms’, in Photorealism in Computer Graphics, Spencer, 1992, pp. 127–135) and Van Wyk's (G.C. Van Wyk Jr., ‘A geometry-based insolution model for computer-aided design,’ Ph.D. Thesis, The University of Michigan, 1998.) methods, which fail to remove hidden surfaces for relatively large patches and cause large discretization errors in formfactors. We also demonstrate that our technique is superior to the hemi-cube method in terms of the computation time. Moreover, we parallelize our approach on a parallel computer with shared memory, and obtain a high performance with our radiosity rendering system. Our method divides a hemisphere-base into regions, and assigns a region to each processor. The approach can be applied to geometrical data generated by CAD systems, and is evaluated in terms of the computation time, the visual effects, and the parallelization performance. © 1998 John Wiley & Sons, Ltd     

Engineering of Injectable Antibiotic-laden Fibrous Microparticles Gelatin Methacryloyl Hydrogel for Endodontic Infection Ablation

This study aimed at engineering cytocompatible and injectable antibiotic-laden fibrous microparticles gelatin methacryloyl (GelMA) hydrogels for endodontic infection ablation. Clindamycin (CLIN) or metronidazole (MET) was added to a polymer solution and electrospun into fibrous mats, which were processed via cryomilling to obtain CLIN- or MET-laden fibrous microparticles. Then, GelMA was modified with CLIN- or MET-laden microparticles or by using equal amounts of each set of fibrous microparticles. Morphological characterization of electrospun fibers and cryomilled particles was performed via scanning electron microscopy (SEM). The experimental hydrogels were further examined for swelling, degradation, and toxicity to dental stem cells, as well as antimicrobial action against endodontic pathogens (agar diffusion) and biofilm inhibition, evaluated both quantitatively (CFU/mL) and qualitatively via confocal laser scanning microscopy (CLSM) and SEM. Data were analyzed using ANOVA and Tukey’s test (α = 0.05). The modification of GelMA with antibiotic-laden fibrous microparticles increased the hydrogel swelling ratio and degradation rate. Cell viability was slightly reduced, although without any significant toxicity (cell viability > 50%). All hydrogels containing antibiotic-laden fibrous microparticles displayed antibiofilm effects, with the dentin substrate showing nearly complete elimination of viable bacteria. Altogether, our findings suggest that the engineered injectable antibiotic-laden fibrous microparticles hydrogels hold clinical prospects for endodontic infection ablation.     

Effect of uniaxiai ratcheting on subsequent creep deformation

Experimental observation and numerical simulation are conducted to clarify the effect of viscosity on deformation of materials. First, creep tests after the primary uniaxial ratcheting are carded out using Type 304 stainless steel. Specimens are subjected to cyclic tension-unloading with step and triangular waves during 20000 seconds as the primary ratcheting. After the ratcheting the subsequent creep test at the maximum stress is conducted during 20000 seconds. The experimental results show that the values of the subsequent creep strain after the ratcheting depend on the wave type and the time period of the ratcheting. The shorter time period of the ratcheting leads to the larger subsequent creep strain. Numerical simulations are also carried out using the constitutive model based on dislocation density [Estrinet al.]. As a result, the equivalent value of the ratcheting strain to creep strain is found out from the simulations and experiments.     

Social and environmental impacts of packaging (LCA and assessment of packaging functions)

This paper reviews the functions of packaging materials and the social and environmental impacts that packaging has, reflecting our changing lifestyle. The functions of some packaging materials, such as prevention of food contamination, protection against spoilage, preservation of contents and communications linking the food manufacturer to the customer, are many and varied in extent and complexity. The current life cycle assessment (LCA) can not easily be applied to the assessment of environmental impacts of packaging materials, taking packaging functions into consideration, but attempts at such application are being made experimentally. Copyright © 2000 John Wiley & Sons, Ltd.     

Repulpable pressure-sensitive adhesive tapes and labels

In recent years, Japan has been witnessing a mounting interest in the recycling of waste paper as a way of protecting the environment. Yet the manufacture of recycled paper has always been subject to the problem of plastic, metal or PE-laminated paper chips mixing in. Especially the contaminants from adhesive tapes and labels (stickies) have posed a difficult problem for the manufacturers of recycled paper. Therefore, the development of repulpable products substituting for them has long been an earnest desire for the industry. To solve this problem, a comprehensive investigation into the pressure-sensitive adhesive, the release agent and the base paper has been carried out, and repulpable PSA packaging tapes and labels that are well suited for the manufacture of recycled paper have been successfully developed. © 1998 John Wiley & Sons, Ltd.     

Radially and azimuthally dependent resonance self-shielding treatment for general multi-region geometry based on a unified theory

A unified resonance self-shielding method, which can treat general sub-divided fuel regions, is developed for lattice physics calculations in reactor physics field. In a past study, a hybrid resonance treatment has been developed by theoretically integrating equivalence theory and ultra-fine-group slowing-down calculation. It can be applied to a wide range of neutron spectrum conditions including low moderator density ranges in severe accident states, as long as each fuel region is not sub-divided. In order to extend the method for radially and azimuthally sub-divided multi-region geometry, a new resonance treatment is established by incorporating the essence of sub-group method. The present method is composed of two-step flux calculation, i.e. ‘coarse geometry + fine energy’ (first step) and ‘fine geometry + coarse energy’ (second step) calculations. The first step corresponds to a hybrid model of the equivalence theory and the ultra-fine-group calculation, and the second step corresponds to the sub-group method. From the verification results, effective cross-sections by the new method show good agreement with the continuous energy Monte-Carlo results for various multi-region geometries including non-uniform fuel compositions and temperature distributions. The present method can accurately generate effective cross-sections with short computation time in general lattice physics calculations.