Numerical investigation of continuous processes for catalytic hydrogenation of nitrile butadiene rubber

Dynamic behavior of continuous processes was numerically investigated for the catalytic hydrogenation of nitrile butadiene rubber, based on developed models, which took into account the coupling between kinetics and mass transfer. The evolution of hydrogenation reaction trajectories in both cases were analyzed. It is proposed that the coupling behavior between the catalytic hydrogenation and mass transfer was completely determined by the ability of the catalyst in activating hydrogen, carbon‐carbon double bond loading level and the relative capacity of reaction to mass transfer as well as the residence time in the reactor. Four dimensionless parameters were derived to characterize these aspects. The effects of operation conditions on the hydrogenation processes were investigated. The application of the ideal flow models to non‐ideal flows was in addition discussed. It is suggested that the optimal reactor for such a hydrogenation system would be a plug flow reactor with an instantaneous well‐mixing component in the inlet of it, and a reasonable approach to the proposed optimal reactor should be with the flow behavior of at least three continuous stirred tank reactors in series. Further research directions are suggested.     

The design and manufacture of a graphite fiber reinforced poly(ether ether ketone) (PEEK) tetrahedron truss array

Orbital space structures are required to be lightweight, have high specific stiffness, have near-zero coefficient of thermal expansion, exhibit low outgassing, and be cost-effective. Graphite-reinforced thermoplastics have the potential to satisfy the criteria noted. However, prior to committing the materials to specific projects, technology demonstration and risk reduction is necessary. In order to demonstrate the application of fiber-reinforced thermoplastic composites for truss structure applications, a graphite-reinforced poly(ether ether ketone) (PEEK) composite tetrahedron truss array was designed and manufactured. The resulting structure clearly demonstrated that fiber-reinforced thermoplastic composites are a viable alternative to epoxy composites for orbital structures.     

Hydrogenation of cis‐1,4‐poly(isoprene) catalyzed by OsHCl(CO)(O2)(PCy3)2

The quantitative hydrogenation of cis‐1,4‐poly(isoprene) (CPIP) provides an easy entry to the alternating copolymer of ethylene–propylene, which is difficult to prepare by conventional polymerization. The homogeneous hydrogenation of CPIP, in the presence of OsHCl(CO)(O₂)(PCy₃)₂ as catalyst, has been studied by monitoring the amount of hydrogen consumed during the reaction. The final degree of olefin conversion measured by computer‐controlled gas uptake apparatus was confirmed by infrared spectroscopy and ¹H nuclear magnetic resonance analysis. Kinetic experiments for CPIP hydrogenation in toluene solvent indicate that the hydrogenation rate is first order with respect to catalyst and carbon–carbon double bond concentration. A second‐order dependence on hydrogen concentration for low values and a zero‐order dependence for higher values of the hydrogen concentration was observed. The apparent activation energy for the hydrogenation of CPIP over the temperature range of 115–140°C was 109.3 kJ/mole. Mechanistic aspects of this catalytic process are discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 142–152, 2003     

Vitamin E Supplementation of Smokers and Non-Smokers

Twenty male smokers and 20 non-smokers took either vitamin E capsules (1000 IU/day) or placebo for 14 days. Erythrocytes from smokers showed a marked tendency to peroxidise in vitro compared with non-smokers, an effect which was abolished by vitamin E supplementation. The increased erythrocyte peroxidation may reflect a lipid hydroperoxide-induced decrease in glucose-6-phosphate dehydrogenase activity. Evidence that smokers incurred a sustained oxidant stress also included increased plasma conjugated dienes, decreased plasma vitamin C and an increase in erythrocyte glutathione. Plasma cholesterol, vitamin E and conjugated dienes increased with age in all groups. Results suggest that smokers are under a sustained oxidant stress, some indices of which can be partially ameliored by vitamin E supplementation.     

Predicting the determinants of the NFC-enabled mobile credit card acceptance: A neural networks approach

The main aim of this study is to determine the factors influencing the adoption of Near Field Communication (NFC)-enabled mobile credit card, an innovation in contactless payment for the future generation. Constructs from psychological science, trust-based and behavioral control theories were incorporated into the parsimonious TAM. Using empirical data and Structural Equation Modeling-Artificial Neural Networks approach together with multi group analysis, the effects of social influence, personal innovativeness in information technology, trust, perceived financial cost, perceived usefulness and perceived ease of use were examined. The significance of indirect effects was examined using the bias-corrected percentile with two-tailed significance through bootstrapping. Gender, age, experience and usage were introduced as the moderator variables with industry being the control variable in the research model. The scarcity in studies regarding the moderating effects of these variables warranted the needs to further investigate their impacts. The mediating effect of perceived usefulness was examined using the Baron–Kenny’s technique. The findings of this study have provided invaluable theoretical, methodological and managerial implications and will contribute to the decision making process by CEOs, managers, manufacturers and policy makers from the mobile manufacturing industry, businesses and financial institutions, mobile commerce, mobile telecommunication providers, mobile marketers, private or government practitioners and etc.     

The moderating role of subordinate political skill on supervisors' impressions of subordinate ingratiation and ratings of subordinate interpersonal facilitation.

Nearly 2 decades ago, social influence theorists called for a new stream of research that would investigate why and how influence tactics are effective. The present study proposed that political skill affects the style of execution of influence attempts. It utilized balance theory to explain the moderating effect of employee political skill on the relationships between self- and supervisor-reported ingratiation. Additionally, supervisor reports of subordinate ingratiation were hypothesized to be negatively related to supervisor ratings of subordinate interpersonal facilitation. Results from a combined sample of 2 retail service organizations provided evidence that subordinates with high political skill were less likely than those low in political skill to have their demonstrated ingratiation behavior perceived by targets as a manipulative influence attempt. Also, when subordinates were perceived by their supervisors to engage in more ingratiation behavior, the subordinates were rated lower on interpersonal facilitation. Implications of these findings, limitations, and future research directions are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and characterization of optical heads for interferometric ballistic velocity measurements

The design of optical fiber based heads offering high accuracy and bandwidth for use in VISAR (velocity interferometer system for any reflector) experiments measuring ballistic velocities is described. A new, expanded, model for predicting the distance-dependent collection efficiency of the heads is presented. The model is shown to agree very well with experimental results, both within and outside the "depth of field". Various optical heads are demonstrated, to suit different experimental setups and conditions. Designs offering options for high bandwidths, accurate prealignment, and large stand-off distances are discussed. Results from a typical VISAR experiment are presented, verifying that our designs yield high-quality data.     

稳步发展的“下半球”数字印刷业

<正>2009年11月下旬,作为中国政府邀请的嘉宾,我参加了在北京召开的"第二届中国服务贸易大会"。这一国际盛会旨在促进中国与相关服务贸易国家和地区的进一步信息交流和接触。在会议期间,我有幸与中国印刷科学技术研究所的管理团队进行了交流,并受到来自他们的热情接待。     

Hydrogenation of a Tri-layer High Performance Elastomer: Substrate Synthesis,Catalytic Latex Hydrogenation,and Catalyst Recovery

A whole set of “green” nano-processes providing hydrogenated PMMA-PS-NBR tri-layer core–shell nanostructured high performance rubbers was developed in this research, which involved the synthesis of diene elastomers as the substrate, followed by the catalytic hydrogenation reaction, and finally catalyst recovery. This study may contribute to the development of hydrogenated high performance elastomers in latex form and recovery of catalyst from the polymer matrix.     

Synthesis of poly(methyl methacrylate) nanoparticles initiated by azobisisobutyronitrile using a differential microemulsion polymerization technique

Nanosized poly(methyl methacrylate) (PMMA) particles with a high molecular weight of 10⁶ g mol^?1 and a polydispersity index of about 1–2 were synthesized, for which 2,2′‐azobisisobutyronitrile was used as the initiator and a differential microemulsion polymerization technique was employed. The kinetics of the polymerization, the glass transition temperature, tacticity, the particle size distribution, and the morphology of the nanosized PMMA synthesized were investigated. The dependence of the number of the polymer particles (N_p) and the number of the micelles (N_m) on the concentration of the surfactant was discussed. The molecular weight distribution was found to be nearly constant over the polymerization time, which was attributed to the significance of micellar polymerization. The resultant nanosized PMMA has a rich syndiotactic configuration (53–57% rr triads) with a glass transition temperature of about 125°C. A beneficial operation condition was discovered where the conversion reached a maximum at a high monomer‐to‐water ratio. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009