Thermal stabilities and flame retardancies of phloroglucinol‐based organo phosphates when applied to polycarbonate

A series of organo phosphorus flame retardants (FRs) based on aromatic phosphate and cyclic phosphate were synthesized in an attempt to develop an efficient FR for polycarbonate. Their successful synthesis was confirmed by FT‐IR and ¹ H and ³¹P NMR. Their thermal stability and flame retarding efficiency as a single‐component additive were investigated and compared with the commercial FR, resorcinol bis(diphenyl phosphate). The thermogravimetric analysis results revealed that the aromatic phosphate synthesized in this study, phloroglucinol diphenyl phosphate (PDP), shows a higher thermal degradation temperature and better flame retardancy even though it has a lower P content than cyclic phosphate‐based FRs. The flame retarding efficiency was evaluated by the UL‐94 test method. The V‐0 rating was achieved at a PDP loading of 2 wt% in polycarbonate in the presence of an anti‐dripping agent (1 wt%), which is better than that of resorcinol bis(diphenyl phosphate) and cyclic phosphate‐based FRs. The high thermal stability and P–OH generation tendency is responsible for the better flame‐retarding performance of PDP. The degradation path of PDP is also discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Predicting the Lifespan and Retweet Times of Tweets Based on Multiple Feature Analysis

In social network services, such as Facebook, Google+, Twitter, and certain postings attract more people than others. In this paper, we propose a novel method for predicting the lifespan and retweet times of tweets, the latter being a proxy for measuring the popularity of a tweet. We extract information from retweet graphs, such as posting times; and social, local, and content features, so as to construct prediction knowledge bases. Tweets with a similar topic, retweet pattern, and properties are sequentially extracted from the knowledge base and then used to make a prediction. To evaluate the performance of our model, we collected tweets on Twitter from June 2012 to October 2012. We compared our model with conventional models according to the prediction goal. For the lifespan prediction of a tweet, our model can reduce the time tolerance of a tweet lifespan by about four hours, compared with conventional models. In terms of prediction of the retweet times, our model achieved a significantly outstanding precision of about 50%, which is much higher than two of the conventional models showing a precision of around 30% and 20%, respectively.     

Conductive adhesive with transient liquid‐phase sintering technology for high‐power device applications

A highly reliable conductive adhesive obtained by transient liquid‐phase sintering (TLPS) technologies is studied for use in high‐power device packaging. TLPS involves the low‐temperature reaction of a low‐melting metal or alloy with a high‐melting metal or alloy to form a reacted metal matrix. For a TLPS material (consisting of Ag‐coated Cu, a Sn96.5‐Ag3.0‐Cu0.5 solder, and a volatile fluxing resin) used herein, the melting temperature of the metal matrix exceeds the bonding temperature. After bonding of the TLPS material, a unique melting peak of TLPS is observed at 356 °C, consistent with the transient behavior of Ag₃Sn + Cu₆Sn₅ → liquid + Cu₃Sn reported by the National Institute of Standards and Technology. The TLPS material shows superior thermal conductivity as compared with other commercially available Ag pastes under the same specimen preparation conditions. In conclusion, the TLPS material can be a promising candidate for a highly reliable conductive adhesive in power device packaging because remelting of the SAC305 solder, which is widely used in conventional power modules, is not observed.     

Optimal replacement strategy for stochastic deteriorating system with random wear limit under periodic inspections

In this paper, we examine the preventive maintenance policies for systems/items which are degraded continuously in time and the degree of deterioration that can be observed through periodic inspection. The items will be replaced preventively if the wear process exceeds a limit at periodic inspection or replaced immediately on failure. The limit is assumed to be random in taking individual variation to withstand damages or unmeasurable variables latent to failure into account. Continuous wear process is modeled via a gamma process. We derive an optimal wear limit for preventive replacement so that the long-run total expected cost per unit time is minimized. The proposed method is applied to a problem of block mat inspection for the barrier’s seabed protection.     

La0.8Sr0.2Cr0.95Ru0.05O3−x and Sm0.8Ba0.2Cr0.95Ru0.05O3−x as partial oxidation catalysts for diesel

La_0.8Sr_0.2Cr_0.95Ru_0.05O_3−x (LSCR) and Sm_0.8Ba_0.2Cr_0.95Ru_0.05O_3−x (SBCR), Ru-substituted perovskite catalysts, are investigated for the partial oxidation (POX) of diesel to produce hydrogen-rich gases for fuel cell applications. Metal-substituted perovskite materials have been investigated as reforming catalysts because the metal atoms are well-dispersed in the perovskite structure. However, Ru de-mixing and a secondary phase of LSCR and SBCR are observed after reduction at high temperature. The thermal stability, sulfur tolerance and aromatic decomposition over LSCR and SBCR are compared to those over Ru on Ce_0.9Gd_0.1O_2−x (CGO). During the thermal stability test, the catalytic activities of LSCR and SBCR improve after operating at 1000 °C. The sulfur tolerance and aromatic decomposition activity of LSCR and SBCR improve when the temperature increases to 950 °C. The improvements are attributed to the de-mixed Ru from the perovskite structure at high temperatures under a reductive atmosphere.     

Who will cross the border? – The transition of political discussion into the newly emerged venues

This study explores the political implications of new communication technologies with a focus on their role as political discussion venues. Assuming that new technologies could expand the sphere for political discourse, we investigate the transition of citizens’ face-to-face political discussion into the computer-mediated online context. With analyses of a representative sample of US adults, this study explicates the link between the traditional and newly emerged discussion venues online. Our results reveal that significant differences in the transition pattern arise from variances in citizens’ political interest and age. In addition, in an attempt to reconcile the two seemingly conflicting hypotheses, we examine the role of political interest and age in the transition process within one integrated theoretical framework. Our findings highlight the conditions under which the democratic potential of the new venues becomes magnified, and draws attention to the importance of examining the dynamics underlying the transition of discussion venues.     

Rice PIN Auxin Efflux Carriers Modulate the Nitrogen Response in a Changing Nitrogen Growth Environment

Auxins play an essential role in regulating plant growth and adaptation to abiotic stresses, such as nutrient stress. Our current understanding of auxins is based almost entirely on the results of research on the eudicot Arabidopsis thaliana, however, the role of the rice PIN-FORMED (PIN) auxin efflux carriers in the regulation of the ammonium-dependent response remains elusive. Here, we analyzed the expression patterns in various organs/tissues and the ammonium-dependent response of rice PIN-family genes (OsPIN genes) via qRT–PCR, and attempted to elucidate the relationship between nitrogen (N) utilization and auxin transporters. To investigate auxin distribution under ammonium-dependent response after N deficiency in rice roots, we used DR5::VENUS reporter lines that retained a highly active synthetic auxin response. Subsequently, we confirmed that ammonium supplementation reduced the DR5::VENUS signal compared with that observed in the N-deficient condition. These results are consistent with the decreased expression patterns of almost all OsPIN genes in the presence of the ammonium-dependent response to N deficiency. Furthermore, the ospin1b mutant showed an insensitive phenotype in the ammonium-dependent response to N deficiency and disturbances in the regulation of several N-assimilation genes. These molecular and physiological findings suggest that auxin is involved in the ammonium assimilation process of rice, which is a model crop plant.     

Antibacterial activities of polyphenols against foodborne pathogens and their application as antibacterial agents

Food Science and Biotechnology - Polyphenols are secondary metabolites produced in higher plants. They are known to possess various functional properties in the human body. Polyphenols also exhibit...     

Reinforcement Q-learning based on Multirate Generalized Policy Iteration and Its Application to a 2-DOF Helicopter

International Journal of Control, Automation and Systems - In this paper, we propose a novel Q-learning method based on multirate generalized policy iteration (MGPI) for unknown discrete-time (DT)...     

The moderation effects of mobile technology advancement and system barrier on m-commerce channel preference behavior

Information Systems and e-Business Management - Mobile commerce, or m-commerce, has quickly become a powerful, indispensable approach for diverse business to consumer (B2C) industries to secure...