Direct conversion of methanol to n-C4H10 and H-2 in a dielectric barrier discharge reactor

Methanol is an important H-carrier and C1 chemical feedstock. In this paper, a direct conversion of methanol to n-C4H10 and H2 was achieved for the first time in a dielectric barrier discharge (DBD) non-thermal plasma reactor. The selective formation of n-C4H10 by limiting COx (x = 1 and 2) generation was obtained by optimizing different plasma processing parameters including the methanol inlet concentration, discharge power, and pre-heating temperature. The results showed that a higher methanol inlet concentration and a higher pre-heating temperature favors the formation of n-C4H10, while a higher methanol inlet concentration and a lower discharge power can effectively limit the formation of CO. The optimal selectivity for n-C4H10 (37.5%), H2 (28.9%) and CO (14%) was achieved, with a methanol conversion of 40.0%, at a methanol inlet concentration of 18 mol%, a discharge power of 30 W and a pre-heating temperature of 140 °C using N2 as a carrier gas. Value-added liquid chemicals (e.g., alcohols, acids, and heavy hydrocarbons) were also obtained from this reaction. Emission spectroscopy diagnostics reveals the formation of various reactive species (e.g., CH, C2, CN, H and metastable N2) in the CH3OH/N2 DBD. Possible reaction pathways for the formation of n-C4H10 were proposed and discussed

A novel three-class ROC method for eQTL analysis

The problem of identifying genetic factors underlying complex and quantitative traits such as height, weight and disease susceptibility in natural populations has become a major theme of research in recent years. Aiming at revealing the inter-dependency and causal relationship between the underlying genotypes and observed phenotypes, researchers from different areas have developed a variety of methods for expression quantitative trait loci (eQTL) mapping. Most of these methods rely on resampling-based algorithms that are computationally very expensive. To overcome the disadvantages of the current techniques, we propose a novel nonparametric method based on the volume under surface (VUS) within the framework of three-class receiver operating characteristic (ROC) analysis. With the fast algorithms developed, we can reduce the computation time of the genomewide analysis from several months down to several days. © 2010 IEEE.published_or_final_versionThe 2010 International Conference on Machine Learning and Cybernetics (ICMLC 2010), Qingdao, China, 11-14 July 2010. In Proceedings of the International Conference on Machine Learning and Cybernetics, 2010, v. 6, p. 3056-306

Detecting dynamic communities in opportunistic networks

In opportunistic networks, communities of mobile entities may be utilized to improve the efficiency of message forwarding. However, identifying communities that are dynamically changing in mobile environment is non-trivial. Based on random walk on graphs, in this paper we present a community detection algorithm that takes into account the aging and weight of contacts between mobile entities. Our idea originates from message-forwarding operations in opportunistic networks. We evaluate the algorithm on both computer-generated networks and real-world human mobility traces. The result shows that our proposed algorithm can find the communities and detect the changes in their structures over time. © 2009 IEEE.published_or_final_versionThe 1st International Conference on Ubiquitous and Future Networks (ICUFN 2009), Hong Kong, China, 7-9 June 2009. In Proceedings of the 1st ICUFN, 2009, p. 159-16

Feasibility of time-lapse AVO and AVOA analysis to monitor compaction-induced seismic anisotropy

Hydrocarbon reservoir production generally results in observable time-lapse physical property changes, such as velocity increases within a compacting reservoir. However, the physical property changes that lead to velocity changes can be difficult to isolate uniquely. Thus, integrated hydro-mechanical simulation, stress-sensitive rock physics models and time-lapse seismic modelling workflows can be employed to study the influence of velocity changes and induced seismic anisotropy due to reservoir compaction. We study the influence of reservoir compaction and compartmentalization on time-lapse seismic signatures for reflection amplitude variation with offset (AVO) and azimuth (AVOA). Specifically, the time-lapse AVO and AVOA responses are predicted for two models: a laterally homogeneous four-layer dipping model and a laterally heterogeneous graben structure reservoir model. Seismic reflection coefficients for different offsets and azimuths are calculated for compressional (P–P) and converted shear (P–S) waves using an anisotropic ray tracer as well as using approximate equations for AVO and AVOA. The simulations help assess the feasibility of using time-lapse AVO and AVOA signatures to monitor reservoir compartmentalization as well as evaluate induced stress anisotropy due to changes in the effective stress field. The results of this study indicate that time-lapse AVO and AVOA analysis can be applied as a potential means for qualitatively and semi-quantitatively linking azimuthal anisotropy changes caused by reservoir production to pressure/stress changes

Stress and its effect on optical properties of GaN epilayers grown on Si(111), 6H-SiC(0001), and c-plane sapphire

Stress and its effects on optical properties of GaN epilayers grown in Si(111), 6H-SiC(0001), and c-plane sapphire were investigated. Large tensile stress was present in GaN epilayers grown on Si and 6H-SiC, and a small compressive stress appeared in the film grown on sapphire. The results showed that the thermal mismatch between the epilayers and the substrates plays a major role in determining the residual strain in the films.published_or_final_versio

4-1BB Ligand Signaling to T Cells Limits T Cell Activation

4-1BB ligand (4-1BBL) and its receptor, 4-1BB, are both induced on T cells after activation, but little is known about the role of 4-1BBL. In this study we show that 4-1BBL can transmit signals that limit T cell effector activity under tolerogenic conditions. Cross-linking 4-1BBL inhibited IL-2 production in vitro, primarily with suboptimal TCR stimulation. Furthermore, naive 4-1BBL-deficient OT-II transgenic T cells displayed a greater conversion to effector T cells in vivo when responding to soluble OVA peptide in wild-type hosts, whereas development of Foxp3(+) regulatory T cells was not altered. A greater number of effector T cells also differentiated from naive wild-type OT-II T cells when transferred into 4-1BB-deficient hosts, suggesting that APC-derived 4-1BB is likely to trigger 4-1BBL. Indeed, effector T cells that could not express 4-1BBL accumulated in larger numbers in vitro when stimulated with 4-1BB-expressing mesenteric lymph node dendritic cells. 4-1BBL was expressed on T cells when Ag presentation was limiting, and 4-1BBL was aberrantly expressed at very high levels on T cells that could not express 4-1BB. Trans-ligation, Ab capture, and endocytosis experiments additionally showed that T cell-intrinsic 4-1BB regulated internalization of membrane 4-1BBL, implying that the strong induction of 4-1BB on T cells may counteract the suppressive function of 4-1BBL by limiting its availability. These data suggest that 4-1BBL expressed on T cells can restrain effector T cell development, creating a more favorable regulatory T cell to effector cell balance under tolerogenic conditions, and this may be particularly active in mucosal barrier tissues where 4-1BB-expressing regulatory dendritic cells present Ag.X11149Ysciescopu

Semiparametric Regression Analysis of Panel Count Data: A Practical Review

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149207/1/insr12271_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149207/2/insr12271.pd

Regression Modeling for Recurrent Events Possibly with an Informative Terminal Event Using R Package reReg

Recurrent event analyses have found a wide range of applications in biomedicine, public health, and engineering, among others, where study subjects may experience a sequence of event of interest during follow-up. The R package reReg offers a comprehensive collection of practical and easy-to-use tools for regression analysis of recurrent events, possibly with the presence of an informative terminal event. The regression framework is a general scalechange model which encompasses the popular Cox-type model, the accelerated rate model, and the accelerated mean model as special cases. Informative censoring is accommodated through a subject-specific frailty without any need for parametric specification. Different regression models are allowed for the recurrent event process and the terminal event. Also included are visualization and simulation tools

Surface atomic arrangement visualization via reference-atom-specific holography

The reference-atom-specific holography was used to study the surface atomic arrangement visualization. By using the low-energy electron diffraction (LEED) intensity spectra, the direct reconstruction of 3D atomic images were demonstrated. A map of interatomic vectors was obtained by a multiple-incident angle and multiple-energy integral applied to spectra. The images of individual atoms in the vicinity of the selected reference atom were produced by a second integral transformation, using the chosen interatomic vector as a filter which was applied to the LEED spectra.published_or_final_versio

Evidence for a Type-II band alignment between cubic and hexagonal phases of GaN

The study of photoluminescence spectra of a series of thin, undoped, hexagonal GaN films containing cubic GaN inclusions grown by molecular-beam epitaxy on 6H-SiC was presented. It was shown that an emission peak at ∼3.17 eV in thin, hexagonal GaN films exhibits behaviors typical of a spatially indirect transition. The values of the band offsets extracted from the data were in good agreement with theoretical predictions.published_or_final_versio