Lubrication of Si3N4 and Al2O3 in water with and without addition of silane coupling agents in the range of 0.05–0.10 mol/l

To improve water lubrication of ceramics at a lower sliding velocity, the effect of the addition of silane coupling agents was investigated. Si₃N₄ and Al₂O₃ were slid against themselves in water with and without the addition of silane coupling agents in amounts ranging from 0.05 to 0.10 mol/l. Silane coupling agents containing one or more amino groups were effective in reducing the friction of Si₃N₄ and Al₂O₃ in water. Si₃N₄ also showed significant wear reduction but not Al₂O₃. However, the addition of a silane coupling agent containing an epoxy group increased both friction and wear of Si₃N₄. Improved lubricative characteristics of Si₃N₄ in water and in silane coupling agent solutions were obtained when Si₃N₄ contained smaller amounts of sintering additives. The adsorption behaviour of a silane coupling agent on ceramics was examined using both Fourier transform infrared spectroscopy and thin layer chromatography to clarify the interaction between the silane coupling agent and the ceramics. The role of polysiloxane film formation on ceramics is discussed to demonstrate the lubrication properties of ceramics.     

Stabilization of poly(vinyl chloride). I. Change in color of poly(vinyl chloride) compounded with some metal soaps

Poly(vinyl chloride) (PVC) with one or more metal salts added was colored by the action of heat to investigate the stabilization mechanism. The coloration and the color difference of heated PVC compound films varied according to the metal salt added. The decoloration of the colored compound films was advanced markedly in THF, DMF, acetone, and ammonia. On the other hand, the heated achromatic PVC film containing Cd/Ba soaps underwent an opposite change, from colorless to yellow orange, in the above materials. This means that the coloration of heated compound films may result from the formation of some complex (for example, π complex of the polyene with the metal chloride). Furthermore, the colored film with cadmium stearate was decolored by roll mixing with the colored film containing barium stearate. These results indicate that the stabilization with metal soaps may be founded on a physical phenomenon such aa an effect of complementary color.     

New proposal of reactivity coefficient estimation method using a gray-box model in nuclear power plants

A new method for estimating reactivity parameters, such as moderator temperature coefficient (MTC) and void reactivity coefficient (VRC), is proposed using steady-state noise data. In order to solve the ill-posed problem of reactivity parameter estimation, a concept of a gray box model is newly introduced. The gray box model includes a first principle based model and a black-box fitting model. The former model acts as a priori knowledge based constraints in a parameter estimation problem. After establishing the gray box and noise source models, the maximum likelihood estimation method based on Kalman filter is applied. Furthermore, it is shown that the frequency domain approach of the gray box model is useful in the case of VRC estimation. The effectiveness of the proposed algorithms is shown through numerical simulation and actual plant data analysis.     

Modification of poly(vinyl chloride). XIX. Electroplating of poly(vinyl chloride)

As a preliminary treatment in the PVC-electroplating procedure, treatment with dimethylformamide followed by sensitization leads to a finely roughened and a highly hydrophilic surface with reducing power. This is caused by the formation of an ionic complex compound between dimethylformamide and tin(II) chloride absorbed in the PVC surface. A much more finely and deeply etched surface which exhibits higher adhesion through the mechanical interlocking effect is obtained with the PVC blends containing the plasticizer with a low value of interaction parameter and with a solubility parameter approximate to that of PVC. Adhesion of the metal layer to the PVC surface thus obtained is improved about 1.5 times by thermal aging at 120°C for 20 min.     

Global open ethernet (GOE) system and its performance evaluation

This paper presents an overview of global open Ethernet (GOE) architecture as a cost-effective Ethernet-based virtual private network (VPN) solution, and discusses a hardware and software implementation of a prototype system. Three main approaches have been proposed for a VPN solution on metro-area network: resilient packet ring, Ethernet over multiprotocol label switching (EoMPLS), virtual bridged local area network-tag stacking (Q-in-Q). None of these schemes can satisfy the following requirements at the same time: network topology flexibility, affordable network functionalities, low equipment cost, and low operational cost. The proposed GOE system is designed to solve VPN management problems of these approaches with MPLS VPN functionality at a low cost of Ethernet-based solution. The key components of GOE are: 1) a novel GOE tag for high-speed switching and 2) a novel routing and protection module via per-destination multiple rapid spanning tree protocol (PD-MRSTP). Via the analytical performance evaluation of EoMPLS, Q-in-Q, and GOE, we show that the memory cost and the network utilization of GOE is two-three times smaller and 22% higher than the other approaches, respectively. We also have developed a GOE prototype system and obtained the following remarkable hardware and software performance results. The GOE core switch delivered 100% of theoretical maximum throughput (10 G) with zero packet loss even with the field programmable gate array platform, and its 10-G port density is 1.5 times denser than the best currently available products. The GOE switch using PD-MRSTP also delivered a significantly fast protection switching time (1.975 ms), which was significantly faster than legacy Ethernet switches. These performance evaluation results prove that the proposed GOE system can be used as a cost-effective high-performance Ethernet-based VPN solution.     

Growth kinetics of grain boundary allotriomorphs of proeutectoid ferrite in Fe-C-Mn-X2 alloys

The parabolic rate constant for the thickening of grain boundary ferrite allotriomorphs at the faces of austenite grain boundaries was measured as a function of isothermal transformation temperature in three Fe-C-X₁-X₂ alloys where X₁ is Mn and X₂ is successively Si, Ni, and Co. The results were compared with the predictions of the local equilibrium model for multi-component systems and with those derived from the theory of growth under paraequilibrium conditions. The distribution of Mn and Si in ferrite and austenite in the Fe-C-Mn-Si alloy was also measured as a function of reaction temperature with transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The observed temperature below which alloying element partition ceased was in good agreement with the local equilibrium model. Whereas the parabolic rate constant for thickening was considerably larger than the amount predicted by this theory in the alloying element diffusion-controlled regime, the opposite was true in the carbon diffusion-controlled regime. Similarly, the calculated paraequilibrium constant was usually considerably larger than that measured experimentally. Synergistic enhancements of the effects of Mn and X₂ in diminishing thickening kinetics were observed for each X₂. The time-temperature-transformation (TTT) curves for the beginning of transformation were calculated from a modified Cahn analysis for the overall kinetics of grain-boundary-nucleated reactions using values of the nucleation rate and the parabolic growth rate constant computed from various models and compared with experimentally determined TTT curves. Substantial discrepancies between the calculated and measured curves were ascribed to synergistic effects of Mn and X₂ upon nucleation and growth kinetics. Formerly Graduate Student, Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA Formerly Mehl Professor Emeritus at Carnegie Mellon University.     

Chemical analyses of mechanochemical reaction products of α-Si3N4 in ethanol and other lower alcohols

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Effect of Hypoxia on Pulmonary Endothelial Cells from Bleomycin-Induced Pulmonary Fibrosis Model Mice

Pulmonary fibrosis is a progressive and fatal disorder characterized by dysregulated repair after recurrent injury. Destruction of the lung architecture with excess extracellular matrix deposition induces respiratory failure with hypoxia and progressive dyspnea. The impact of hypoxia on pulmonary endothelial cells during pulmonary fibrogenesis is unclear. Using a magnetic-activated cell sorting system, pulmonary endothelial cells were isolated from a mouse model of pulmonary fibrosis induced by intratracheally administered bleomycin. When endothelial cells were exposed to hypoxic conditions, a hypoxia-inducible factor (HIF)-2α protein was detected in CD31- and α-smooth muscle actin (SMA)-positive cells. Levels of plasminogen activator inhibitor 1, von Willebrand factor, and matrix metalloproteinase 12 were increased in endothelial cells isolated from bleomycin-treated mice exposed to hypoxic conditions. When endothelial cells were cultured under hypoxic conditions, levels of fibrotic mediators, transforming growth factor-β and connective tissue growth factor, were elevated only in endothelial cells from bleomycin-treated and not from saline-treated lungs. The increased expression of α-SMA and mesenchymal markers and collagen production in bleomycin- or hypoxia-stimulated endothelial cells were further elevated in endothelial cells from bleomycin-treated mouse lungs cultured under hypoxic conditions. Exposure to hypoxia damaged endothelial cells and enhanced fibrogenesis-related damage in bleomycin-treated pulmonary endothelial cells.     

Macrophage Activation Markers Predict Liver-Related Complications in Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) has a wide variation in clinical presentation and course. There is no significant correlation between these symptoms and the disease stage, although patients with more advanced stages generally have more symptoms. It is important to develop biomarkers in order to identify patients with an increased risk of complications and end-stage liver disease. This study investigated surrogate markers for risk estimation of PBC-related complications, including a study population of 77 patients with PBC who underwent liver biopsy and were measured for serum levels of macrophage activation markers, soluble CD163 (sCD163), soluble mannose receptor (sMR), and zonulin. Patients with PBC were divided into symptomatic (Group S, n = 20) and asymptomatic (Group A, n = 57) groups. The correlations of histological stages based on both Scheuer and Nakanuma classifications with the three serum markers were investigated. The Nakanuma classification involves grading for liver fibrosis and bile duct loss. The three biomarkers were assessed for their diagnostic ability to identify patients with PBC having high risk of developing complications. The predictive factors of these complications were examined as well. Group S had significantly higher serum sMR (p = 0.011) and sCD163 (p = 0.048) levels versus Group A. A composite index of sMR and sCD163 measurements had significantly better prediction performance than sCD163 alone (p = 0.012), although not when compared to sMR alone (p = 0.129). Serum sMR was an independent factor for developing complications on both univariate (Odds ratio (OR) = 30.20, 95% confidence interval (95% CI): 3.410–267.0, p = 0.00220), and multivariate (OR = 33.70, 95% CI: 3.6600–311.0, p = 0.0019) analyses. Patients with PBC having sMR of ≥56.6 had a higher incidence of clinical complications versus those with a sMR of <56.6. Serum sMR predicts the development of complications in patients with PBC. sMR plus sCD163 showed better predictive power than either marker alone, although the addition of sCD163 did not improve the predictive power of sMR. Future prospective studies are required in order to validate the findings of the present study.     

Crosslinking of PVC and NBR blends

The purpose of our work is to control the interfacial bonds between PVC and NBR using the ammonium salts of triazine thiols and dithiodimorpholine (DTDM) and thereby reveal the relation between the interfacial bonds and the final mechanical properties of products. In the experimental work a two-stage process was used. At first, an NBR/PVC blend was mixed with a mono-tetra-n-butylammonium salt of triazine trithiol at a temperature of 100°C on a two-roll mill to give the branching structure of triazine thiols into PVC. In the second stage branched NBR/PVC reacted with DTDM to afford the branched PVC containing trithiomorphonyl groups. In the presence of ZnO at 160°C trithiomorphonyl groups react with NBR to form a crosslinking structure between NBR and PVC. The mechanical properties of cured NBR/PVC blends were markedly improved by the treatment process and after addition of tetramethylthiuram monosulphide also. The mechanical properties were not improved by increasing the concentration of TT-TBA (tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol) over 4.2 phr.