The Investigation of Platinum-Tellurium/Aluminum-Oxide and Platinum-Antimony/Aluminum-Oxide Bimetallic Reforming Catalysts.

PtTe/Al\sb2O\sb3 and PtSb/Al\sb2O\sb3 bimetallics were characterized as possible reforming catalysts by kinetic studies, mechanistic investigations, and spectroscopic measurements. The results were compared with Pt/Al\sb2O\sb3 with the aim to understand the effects of tellurium and antimony on the platinum function. Coimpregnated PtTe/Al\sb2O\sb3 and PtSb/Al\sb2O\sb3 catalysts exhibited an increase in selectivity for the isomerization of n-hexane. This enhancement in selectivity can be caused either by electronic effects, which increase the specific activities for isomerization, or by geometric effects, which reduce the rate of hydrocracking. The results of the kinetic experiments, along with FTIR spectroscopy of adsorbed carbon monoxide using the isotopic dilution method, suggest that electronic effects can be identified with Te/Pt alloying in catalysts of low (Te/Pt $\u3c$ 0.06) tellurium content, while geometric effects predominate in catalyst formulations more concentrated in the post-transition metal for both PtTe/Al\sb2O\sb3 and PtSb/Al\sb2O\sb3. The cyclohexane dehydrogenation turnover frequencies were also enhanced at low Te/Pt ratio; in this respect the dehydrogenation and isomerization reactions are similar. Direct six-member ring closure, rather than ring expansion by way of an adsorbed methylcyclopentane intermediate, accounted for most of the production of benzene. The isomerization reactions of carbon-13 labeled 2-methylpentane were used to determine the relative contributions of cyclic and bond shift mechanisms. n-Hexane was formed primarily by a C\sb5 cyclic mechanism on the platinum surface, while 3-methylpentane was produced by both cyclic and bond shift mechanisms. Isomerization via bond shifts increases when tellurium or antimony is added to Pt/Al\sb2O\sb3. The reaction of benzene and deuterium at 110 and 250\sp\circC showed that carbon-hydrogen bond breaking/making is extremely fast. Since diffusion may affect the deuterium levels in the hydrocarbon molecules, no other firm conclusions may be drawn. PtTe/Al\sb2O\sb3 catalysts were also prepared by vapor deposition of tellurium onto Pt/Al\sb2O\sb3. These catalysts exhibited selectivities which were influenced by the type of carrier gas used to deposit the tellurium. A carrier gas containing n-hexane improved the selectivity relative to hydrogen or helium carrier gases. The mechanism of this selectivity effect is unknown but possibly due to carbon incorporation into a Pt-Te alloy

Commentary on the Regulation of Viral Proteins in Autophagy Process

The ability to subvert intracellular antiviral defenses is necessary for virus to survive as its replication occurs only in the host cells. Viruses have to modulate cellular processes and antiviral mechanisms to their own advantage during the entire virus life cycle. Autophagy plays important roles in cell regulation. Its function is not only to catabolize aggregate proteins and damaged organelles for recycling but also to serve as innate immunity to remove intracellular pathogenic elements such as viruses. Nevertheless, some viruses have evolved to negatively regulate autophagy by inhibiting its formation. Even more, some viruses have employed autophagy to benefit their replication. To date, there are more and more growing evidences uncovering the functions of many viral proteins to regulate autophagy through different cellular pathways. In this review, we will discuss the relationship between viruses and autophagy and summarize the current knowledge on the functions of viral proteins contributing to affect autophagy process

Assessing the Integrity of Spillway Foundations

The erosion under a spillway can be a long-term issue that threatens the structural integrity of a water reservoir. The spillway under investigation was suspected to be defective after it had been commissioned in 1987 (Figure 1). Potholes and subsurface cavities were confirmed in the safety assessment using various NDT techniques including ground penetrating radar and impact echo. The GPR inspection was able to differentiate the intact region from the cavities under concrete slabs (Figure 2). The impact echo results and associated analyses provided further evidence of inferior condition in the soil under the concrete slabs. The engineering team designed and executed the repair project based on the conclusion of the integrity assessment. Subsequent GPR inspection has been performed so as to monitor the integrity of the spillway in a period of 18 months following the repair

The Third Stage Management Project of Climate Change Impacts and Adaptation on Water Environment (2/5)

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

Theoretical and bifurcation analysis of a flexible rotor supported by gas-lubricated bearing system with porous bushing

The bifurcation behaviors of a flexible rotor supported by gas-lubricated bearing system with porous bushing are analyzed by a novel numerical method combining the finite difference method and differential transformation method. The results obtained by proposed method are verified with traditional finite difference method, and the analytical results by these two methods are consistent and also in good agreement. Furthermore, the dynamic orbits, power spectra, bifurcation diagram, Poincaré maps and maximum Lyapunov exponent are used to confirm the changes of rotor behavior as the rotor mass is increased. The results show that the rotor center reveals complex dynamic behaviors including periodic, sub-harmonic and chaotic motions. Especially, the rotor bearing system behaves chaos over the ranges of rotor mass 10.7 ≤ms< 13.8 kg. The current results provide an effective means of the gas bearing systems and further understanding of the nonlinear dynamic behavior of bearing systems characterized by different rotor masses

Application-Based Online Traffic Classification with Deep Learning Models on SDN Networks

The traffic classification based on the network applications is one important issue for network management. In this paper, we propose an application-based online and offline traffic classification, based on deep learning mechanisms, over software-defined network (SDN) testbed. The designed deep learning model, resigned in the SDN controller, consists of multilayer perceptron (MLP), convolutional neural network (CNN), and Stacked Auto-Encoder (SAE), in the SDN testbed. We employ an open network traffic dataset with seven most popular applications as the deep learning training and testing datasets. By using the TCPreplay tool, the dataset traffic samples are re-produced and analyzed in our SDN testbed to emulate the online traffic service. The performance analyses, in terms of accuracy, precision, recall, and F1 indicators, are conducted and compared with three deep learning models