bluuebunny/crossref_metadata_2025 huggingface dataset:
Glass Ceramic Seal for Electrochemical Devices
Authors: Reis Signo T. , Schwartz Matthieu
Published: October 2013

Glass-ceramic seals play an important role in the performance of electrochemical devices like solid oxide fuel cell (SOFC), high temperature electrolysis (HTE) and ceramic membrane reactors. In addition to gas tightness and electrical resistivity, a seal material must have a set of thermo-mechanical and chemical properties in order to efficiently seal the SOFC cell components and to maintain performance at elevated temperature over extended operating time. The seal must be stable in oxidizing and reducing atmospheres and withstand thermal cycles between room and the cell typical operating temperature (800 to 900°C). Chemical reaction with the SOFC components should be minimal so as to keep integrity of the seal/cell-interface and prevent degradation in seal reliability over time. In this work, the glass-ceramic seal is discussed for which optimal sintering/crystallization behaviors and thermal stability have been demonstrated. The investigation of the sealant was performed from the point of view of sealing ability and crystallization behavior using Differential Scanning Calorimetry (DSC). The evolution of the seal Coefficient of Thermal Expansion (CTE) has been followed by dilatometric analysis, crystalline phase evolution has been investigated by X-Ray Diffraction (XRD) and the chemical interaction between sealant and cell components has been evaluated by Scanning Electron Microscope (SEM) and Electron Probe Micro Analysis (EPMA).
Computational Studies on Ionic and Electronic Conduction of Rare-Earth-Based Oxides Based on Density Functional Theory
Authors: Sakaue Mamoru , Kasai Hideaki , Ishihara Tatsumi
Published: October 2013

We studied atomic and electronic properties of La2GeO5- and CeO2-based materials by first-principles calculations based on density functional theory. We investigate the properties in a viewpoint of application to solid electrolytes based on analyses of stable structures, total energies, electronic densities of states, oxygen migration paths and activation energies in the paths. Based on the results, we will discuss the potentials of the materials as solid electrolytes and give guiding principles for materials design.
Coverage Dependent Thermodynamics for Sulfur Poisoning of Ni Based Anodes
Authors: Monder Dayadeep S. , Karan Kunal
Published: October 2013

We present an ab-initio thermodynamics model for sulfur poisoning of Ni. This model explicitly includes both the competitive adsorption of H2 and H2S as well as adsorbate coverage effects. Our results show that the adsorption energy for both H2S and H2 on Ni is a strong function of surface species coverage while the entropy of adsorption is weakly dependent on coverage. We outline the derivation of the coverage-dependent surface species chemical potential, use it to calculate the predicted equilibrium coverages of S and H on Ni across a wide range of industrially relevant reaction conditions, and compare our results with data in the literature.
Electrode Reoxidation in Solid-Oxide Cells: Detailed Modeling of Nickel Oxide Film Growth
Authors: Neidhardt Jonathan P. , Kee Robert J. , Bessler Wolfgang G.
Published: October 2013

The lifetime and performance of solid-oxide fuel cells (SOFC) and electrolyzer cells (SOEC) can be significantly degraded by oxidation of nickel within the electrode and support structures. This paper documents a detailed computational model describing nickel oxide (NiO) formation as a growing film layer on top of the nickel phase in Ni/YSZ composite electrodes. The model assumes that the oxidation rate is controlled by transport of ions across the film (Wagner’s theory). The computational model, which is implemented in a two-dimensional continuum framework, facilitates the investigation of alternative chemical reaction and transport mechanisms. Model predictions agree well with a literature experimental measurement of oxidation-layer growth. In addition to providing insight in interpreting experimental observations, the model provides a quantitative predictive capability for improving electrode design and controlling operating conditions.
Optimal Operational Strategies for Degrading Solid Oxide Fuel Cells
Authors: Williams Mark C. , Gemmen Randall , Gerdes Kirk
Published: October 2013

The operational strategy for a solid oxide fuel cell undergoing degradation is investigated in this paper. While the perfect fuel cell would undergo no degradation, practical fuel cells of any type (e.g., polymer electrolyte, etc.), like batteries, will degrade. For fuel cells, dominant mechanisms of degradation will depend on materials of construction, operating conditions, and operational history. The common practice is to linearize degradation. Giving a linear representation to degradation rate, however, gives a linear structure to the area specific resistance, ASR(t). Experimental evidence shows that ASR(t) is commonly a parabolic function. Four important operational strategies are evaluated for degrading fuel cells – constant voltage, constant current, maximum power, and constant design power. This work demonstrates that degrading fuel cells exhibit a natural exergetic efficiency for a given fuel utilization. This exergetic efficiency is constant along the path of maximum power. To operate at this exergetic efficiency is to operate along the path of maximum power. The path of maximum power can be pursued as an operational strategy by varying the fuel flow rate (fuel cell current) at constant fuel utilization. A separate question of possible concern is what is the maximum allowable current.
Nonlinear Oscillatory Dynamics in Solid Oxide Fuel Cells
Authors: Sands Jonathan David , Needham David , Uddin Jamal
Published: October 2013

It is widely known that electrochemical systems may exhibit oscillatory dynamics, and SOFC’s have been shown to produce both current and voltage oscillations, as well as oscillations in chemical species and temperature. The relationships between the various fuel cell phenomena are complex, and a number of theoretical and experimental approaches exist for determining the existence of oscillations. In the approach used here, a dynamical system has been constructed, describing the reaction and diffusion within the anode of an SOFC fueled with methane, in order to analyse the dynamic behaviour of the chemical species. Phase plane analysis shows the occurrence of spontaneous chemical oscillations via a Hopf bifurcation. This paper implements the dynamical system model using physically controlled parameters.
Molecular Dynamics Simulation Studies of H Diffusion in SOFC Anode Using Reactive Force Field
Authors: Saha Leton Chandra , Nakao Kazuhide , Kohno Haruhiko , Ishimoto Takayoshi , Koyama Michihisa
Published: October 2013

Employing reactive molecular dynamics simulation, we investigated diffusion pathways of H-atoms into the bulk from the Ni(100) surface. We found that surface pathway is dominant compared to bulk pathway for H atoms diffusion. Our simulation suggests that H atoms can diffuse into the bulk Ni. From 973 to 1273 K, H atoms migration into bulk is observed, but number of H atom is influenced by the temperature. At 1273 K, 30 % H atoms move into the bulk region. Diffusion barrier of H into bulk is calculated higher than the surface pathway. Diffusion coefficient of H between bulk and surface pathway is calculated to be one order of magnitude discrepancy.
Numerical Prediction of System Efficiency of Solid Oxide Redox Flow Battery During Charge/Discharge Process
Authors: Iwai Hiroshi , Ohmori Hiroko , Itakura Kotaro , Saito Motohiro , Yoshida Hideo
Published: October 2013

A system simulation model of a solid oxide redox flow battery (SORFB) was developed and calculations were carried out to investigate fundamental characteristics of the system. The SORFB is a new-type storage battery consisting of solid oxide electrochemical cell (SOEC) and redox metal; as redox metal, iron is assumed. The developed model is based on 0-D models of the consisting components such as SOEC, redox reactor and heat exchangers. The energy flow of one cycle of charge/discharge operation was evaluated. The results provide foundation for discussion on the system efficiency of SORFB.
Microstructural Analysis of an LSCF Cathode Using In Situ Tomography and Simulation
Authors: Cooper Samuel J. , Kishimoto Masashi , Tariq Farid , Bradley Robert S , Marquis Andrew J , Brandon Nigel P. , Kilner John A. , Shearing Paul R
Published: October 2013

Electrode tortuosity factor is a key input parameter in many fuel cell simulations. Three-dimensional microstructural data obtained from in-situ synchrotron X-ray nano-computed tomography is used as the basis for comparing five approaches to quantify the tortuosity factor. Three of these techniques are based on diffusivity simulations and showed strong correlation, but had consistently different absolute values. A random walk method showed a good degree of correlation to the diffusive approaches, but had the largest values overall. Lastly, a calculation that used a mean pore centroid approach showed little correlation to any of the other three methods, but compared well with the conventional Bruggeman correlation. Due to the diffusive nature of the ionic transport in electrodes, the authors would recommend calculating tortuosity factors using a diffusive approach based on the voxels rather than a remeshed volume.
Dynamic Modeling and Control Design for a Planar Solid Oxide Fuel Cell
Authors: Yu Dung-Di , Lee Ruey-Yi
Published: October 2013

In this paper, a preliminary control law, on the basis of the model-based analysis, is adopted to allow convenient integrations into a comprehensive power tracking control algorithm. The dynamic modeling methodology is employed to assess the dynamic responses of a SOFC stack under startup and load change conditions. The multi-disciplinary integration method is used to evaluate the stack characteristics. Effects of gas flow rates and differential temperatures between inlet flows and stack are investigated. In accordance with the stack specifications, the results will serve as a practical perception to minimize the heat input and shorten the startup time. While under load change conditions, proper air excess ratios are essential to stabilize the stack temperature profiles and to avoid the occurrence of abrupt temperature gradients in the stack.
Development of Interatomic Potential for Molecular Dynamics Simulation of Ni/YSZ Anode in Solid Oxide Fuel Cells
Authors: Iskandarov Albert M , Kubo Atsushi , Umeno Yoshitaka
Published: October 2013

Molecular dynamics (MD) simulations of processes occurring in SOFC anodes require accurate description of atomic interactions. Typical SOFC anode represents nanoporous compound of Ni and yttria-stabilized zirconia (YSZ), and the main process, fuel oxidation, takes place in triple phase boundaries (TPB). Thus it is of importance, in particular, to reproduce bulk and surface properties of YSZ in order to describe interactions in TPBs with reasonable accuracy. In present paper we incorporate many-body interatomic potential based on dipole model for cubic YSZ. Parameters of the model have been determined by fitting energies, stresses and forces to their values derived from ab initio calculations. Classical MD simulations with the developed potential revealed its ability to describe YSZ surface energies and structures. The effect of temperature and yttria concentration on oxygen ions is studied and discussed.
Detailed Transport-Reaction Models for SOFC Ni-YSZ Patterned Anodes: A Critical Inquiry
Authors: Kohno Haruhiko , Liu Shixue , Ogura Teppei , Ishimoto Takayoshi , Monder Dayadeep S. , Karan Kunal , Koyama Michihisa
Published: October 2013

Understanding the detailed physicochemical mechanisms for the electro-oxidation of fuel at the triple phase boundaries (TPBs) in solid oxide fuel cell (SOFC) anodes is a key step towards improving SOFC performance. Significant efforts have been directed toward this goal via both experimental and computational modeling studies. In particular, patterned Ni anode on a planar YSZ substrate has been examined because of its well-defined two-dimensional geometry that in principle offers the advantages of known TPB length and minimization of mass transport effects. A common formulation for such patterned anodes considers modeling of surface reactions and diffusion on both electrode and electrolyte surfaces, along with charge-transfer reactions at the TPBs based on elementary kinetics. In this study, we review the theoretical approaches proposed by several authors and offer a critique of their methods.
Monte Carlo Study on the Constraint Effect of YSZ Phase on Ni Sintering in Ni-YSZ Composite System
Authors: Hara Shotaro , Shikata Kentaro , Shikazono Naoki , Izumi Satoshi , Sakai Shinsuke
Published: October 2013

We present three-dimensional kinetic Monte Carlo (KMC) simulations based on Q-state Potts model in order to numerically predict the microstructural evolution of the Ni-YSZ composite system. By incorporating a new densification algorithm into a previous sintering modeling, we have successfully simulated the effect of the presence of rigid YSZ phase on Ni coarsening kinetics. We reveal that the growth of Ni particle is significantly suppressed when the volume fraction of YSZ phase increases or the particle size of YSZ phase decreases. This indicates that Zener pinning concept widely applied to polycrystalline materials is available for characterizing the particle growth behavior in cermet systems.
Copper-Iron-Ceria-YSZ Anode for Direct Utilization of Hydrocarbons in Solid Oxide Fuel Cells
Authors: Kaur Gurpreet , Basu Suddhasatwa
Published: October 2013

In recent years, Cu-CeO2/YSZ anode materials have been investigated as alternative anode materials for direct oxidation of variety of hydrocarbons for SOFC applications. However, the thermal stability of Cu-CeO2 anode at operating temperature greater than 700 °C is a major concern. The paper reports a use of Fe species as a textural promoter to prevent Cu sintering at high temperature. Cu-Fe/CeO2-YSZ anodes for molar ratio of Cu-Fe of 1:0 and 1:1 prepared by wet impregnation method in tape casted porous YSZ cermets. It was observed that addition of Fe in Cu-CeO2/YSZ anodes improved the performance of SOFC. Cu-Fe/CeO2-YSZ anodes having molar ratio of Cu-Fe of 1:1 showed power density of 180, 77 and 172 mW/cm2 in H2, CH4 and n-C4H10 fuels at 800 °C. Moreover, the performance of SOFC increases with the increase in temperature, Cu-Fe metal loading, and with addition of 1 wt% Pd in Cu-Fe/CeO2-YSZ anodes. The long term stability of Cu-Fe/CeO2-YSZ anodes for Cu-Fe molar ratio of 1:1 is presented while operating SOFC on H2, CH4 and n-C4H10 fuels at 800 °C
Atomic Layer Deposition of Ruthenium on Platinum Anode for Direct Methanol Solid Oxide Fuel Cells
Authors: Jeong Heon Jae , Kim Jun Woo , Bae Kiho , Jung Hojean , Shim Joon Hyung
Published: October 2013

Ru was deposited onto Pt by atomic layer deposition to fabricate anodes for direct methanol solid oxide fuel cells (SOFCs). The performance of the SOFCs with Ru/Pt anodes regarding methanol oxidation was compared with that of the SOFCs with pure Pt anodes. The values of maximum power density of the Ru/Pt SOFC were 4.1 mW/cm2 at 400 °C and 7.8 mW/cm2 at 450 °C. The electrochemical properties of the SOFCs were analyzed by the electrochemical impedance spectroscopy. The morphology of Ru on the microporous Pt was investigated via scanning electron microscopy.
Impact of Trace H2S Contained in a Simulated Coal Derived Syngas or Hydrogen-Enriched Fuel Gas on Performance of Ni-YSZ SOFC Anode
Authors: Kuramoto Koji , Fukushima Toshiyo , Hosokai Sou , Matsuoka Koichi , Suzuki Yoshizo , Kishimoto Haruo , Yamaji Katsuhiro , Horita Teruhisa , Yokokawa Harumi
Published: October 2013

The integration of gasification and solid oxide fuel cells is promising direction to meet the demand of clean and efficient utilization of coal for power generation. This study focused on the impact on performance of Ni-YSZ SOFC anode of ppm-level H2S contamination in wet hydrogen or simulated coal syngas (mixtures of H2 and CO). We observed that the trace level contamination of fuel with H2S ranged from 0.02 to 2ppm resulted in the irrecoverable performance loss and slight acceleration of chemical degradation of anode which depended on the concentration of H2S. We also found that the injection of contaminated simulated coal syngas led to the faster degradation compared to the case with hydrogen injection.
Performances of Doped Ceria Hydrogen Electrodes with Highly Dispersed Ni-Based Nanoparticles for Solid Oxide Electrolysis Cells
Authors: Uchida Hiroyuki , Puengjinda Pramote , Miyano Kohei , Nishino Hanako , Kakinuma Katsuyoshi , Deki Shigehito , Watanabe Masahiro
Published: October 2013

For the hydrogen electrode in the solid oxide electrolysis cell (SOEC), nanometer-sized Ni catalysts were highly dispersed on samaria-doped ceria (SDC). It was found that the current density on Ni-dispersed SDC at 900 °C and the potential of ‒1.0 V vs. air increased by 1.5 times with decreasing the Ni particle size from 70 nm to 40 nm, even when the Ni-loading was decreased from 17 vol.% to 8 vol.%.
Development of a Cost-Efficient and Performing High Temperature Steam Electrolysis Stack
Authors: Reytier Magali , Cren Julie , Petitjean Marie , Chatroux André , Gousseau Georges , Di Iorio Stéphane , Brevet Aude , Noirot-Le Borgne Isabelle , Mougin Julie
Published: October 2013

The main challenges for High Temperature Steam Electrolysis (HTSE) to become competitive towards other hydrogen production technologies are the increase of performance and durability and the decrease of cost. For that purpose, a “low-weight” stack has been designed, including advanced cells and stack components. A performance of -1.9 A.cm-2 at the thermoneutral voltage of 1.3 V has been obtained at 800°C at the scale of a 3-cell stack and its robustness upon thermal cycling has been validated. The upscaling of the technology has been checked with a stack of 10 cells that allowed producing 0.9 Nm3.h-1 of hydrogen. Techno-economical analysis showed that this low-weight design led to a considerable decrease of the stack cost.
Biogas Upgrading Using SOEC with a Ni-ScYSZ Electrode
Authors: Ebbesen Sune Dalgaard , Hansen John Bøgild , Mogensen Mogens
Published: October 2013

Biogas consists mainly of CH4, CO2 and small amounts of H2S. The value of biogas will increase significantly if it is upgraded to pipeline quality by converting CO2 and H2O in the biogas to CO and H2 using a Solid Oxide Electrolysis Cell (SOEC) followed by methanation. The Ni-ScYSZ-cermet electrode is, however, active for steam reforming of CH4, but sulphur traces in the biogas reduce the steam reforming activity. It is proven that sulphur stops steam reforming activity whereas the electrochemistry is only affected to a limited degree, showing that up-grading of biogas using SOEC with Ni-ScYSZ electrode is feasible.
Group Analysis and New Explicit Solutions of Simplified Modified Kawahara Equation with Variable Coefficients
Authors: Wang Gang-Wei , Xu Tian-Zhou
Published: October 2013

The simplified modified Kawahara equation with variable coefficients is studied by using Lie symmetry method. Then we obtain the corresponding Lie algebra, optimal system, and the similarity reductions. At last, we also give some new explicit solutions for some special forms of the equations.
Trail Overexpression Inversely Correlates with Histological Differentiation in Intestinal-Type Sinonasal Adenocarcinoma
Authors: Re M. , Santarelli A. , Mascitti M. , Bambini F. , Lo Muzio L. , Zizzi A. , Rubini C.
Published: October 2013

Introduction. Despite their histological resemblance to colorectal adenocarcinoma, there is some information about the molecular events involved in the pathogenesis of intestinal-type sinonasal adenocarcinomas (ITACs). To evaluate the possible role of TNF-related apoptosis-inducing ligand (TRAIL) gene defects in ITAC, by investigating the immunohistochemical expression of TRAIL gene product in a group of ethmoidal ITACs associated with occupational exposure.Material and Methods. Retrospective study on 23 patients with pathological diagnosis of primary ethmoidal ITAC. Representative formalin-fixed, paraffin-embedded block from each case was selected for immunohistochemical studies using the antibody against TRAIL. Clinicopathological data were also correlated with the staining results.Results. The immunohistochemical examination demonstrated that poorly differentiated cases showed a higher percentage of TRAIL expressing cells compared to well-differentiated cases. No correlation was found with other clinicopathological parameters, including T, stage and relapses.Conclusion. The relationship between upregulation of TRAIL and poorly differentiated ethmoidal adenocarcinomas suggests that the mutation of this gene, in combination with additional genetic events, could play a role in the pathogenesis of ITAC.
An Accelerated Proximal Gradient Algorithm for Singly Linearly Constrained Quadratic Programs with Box Constraints
Authors: Han Congying , Li Mingqiang , Zhao Tong , Guo Tiande
Published: October 2013

Recently, the existed proximal gradient algorithms had been used to solve non‐smooth convex optimization problems. As a special nonsmooth convex problem, the singly linearly constrained quadratic programs with box constraints appear in a wide range of applications. Hence, we propose an accelerated proximal gradient algorithm for singly linearly constrained quadratic programs with box constraints. At each iteration, the subproblem whose Hessian matrix is diagonal and positive definite is an easy model which can be solved efficiently via searching a root of a piecewise linear function. It
is proved that the new algorithm can terminate at an ε‐optimal solution within iterations. Moreover, no line search is needed in this algorithm, and the global convergence can be proved under mild conditions. Numerical results are reported for solving quadratic programs arising from the training of support vector machines, which show that the new algorithm is efficient.
Generalized Exponential Trichotomies for Abstract Evolution Operators on the Real Line
Authors: Lupa Nicolae , Megan Mihail
Published: October 2013

This paper considers two trichotomy concepts in the context of abstract evolution operators. The first one extends the notion of exponential trichotomy in the sense of Elaydi-Hajek for differential equations to abstract evolution operators, and it is a natural extension of the generalized exponential dichotomy considered in the paper by Jiang (2006). The second concept is dual in a certain sense to the first one. We prove that these types of exponential trichotomy imply the existence of generalized exponential dichotomy on both half-lines. We emphasize that we do not assume the invertibility of the evolution operators on the whole spaceX(unlike the case of evolution operators generated by differential equations).
Comparison of Stress-Hemoconcentration Correction Techniques for Stress-Induced Coagulation
Authors: Austin Anthony W. , Patterson Stephen M.
Published: October 2013

When examining stress effects on coagulation, arithmetic correction is typically used to adjust for concomitant hemoconcentration but may be inappropriate for coagulation activity assays. We examined a new physiologically relevant method of correcting for stress-hemoconcentration. Blood was drawn from healthy men (N=40) during baseline, mental stress, and recovery, and factor VII activity (FVII:C), factor VIII activity (FVIII:C), activated partial thromboplastin time (APTT), prothrombin time (PT%), fibrinogen, D-dimer, and plasma volume were determined. Three hemoconcentration correction techniques were assessed: arithmetic correction and two reconstitution techniques using baseline plasma or physiological saline. Area-under-the-curve (AUC) was computed for each technique. For FVII:C, uncorrected AUC was significantly greater than AUC corrected arithmetically. For PT%, uncorrected AUC was significantly greater than AUC corrected with saline or arithmetically. For APTT, uncorrected AUC was significantly less than AUC corrected with saline and greater than AUC corrected arithmetically. For fibrinogen, uncorrected AUC was significantly greater than AUC corrected with saline or arithmetically. For D-dimer, uncorrected AUC was significantly greater than AUC corrected arithmetically. No differences in AUC were observed for FVIII:C. Saline reconstitution seems most appropriate when adjusting for hemoconcentration effects on clotting time and activity. Stress-hemoconcentration accounted for the majority of coagulation changes.
Glutathione Redox System in β‐Thalassemia/Hb E Patients
Authors: Kalpravidh Ruchaneekorn W. , Tangjaidee Thongchai , Hatairaktham Suneerat , Charoensakdi Ratiya , Panichkul Narumol , Siritanaratkul Noppadol , Fucharoen Suthat
Published: October 2013

β‐thalassemia/Hb E is known to cause oxidative stress induced by iron overload. The glutathione system is the major endogenous antioxidant that protects animal cells from oxidative damage. This study aimed to determine the effect of disease state and splenectomy on redox status expressed by whole blood glutathione (GSH)/glutathione disulfide (GSSG) and also to evaluate glutathione‐related responses to oxidation in β‐thalassemia/Hb E patients. Twenty‐seven normal subjects and 25 β‐thalassemia/Hb E patients were recruited and blood was collected. The GSH/GSSG ratio, activities of glutathione‐related enzymes, hematological parameters, and serum ferritin levels were determined in individuals. Patients had high iron‐induced oxidative stress, shown as significantly increased serum ferritin, a decreased GSH/GSSG ratio, and increased activities of glutathione‐related enzymes. Splenectomy increased serum ferritin levels and decreased GSH levels concomitant with unchanged glutathione‐related enzyme activities. The redox ratio had a positive correlation with hemoglobin levels and negative correlation with levels of serum ferritin. The glutathione system may be the body’s first‐line defense used against oxidative stress and to maintain redox homeostasis in thalassemic patients based on the significant correlations between the GSH/GSSH ratio and degree of anemia or body iron stores.
Damage and Failure Process of Concrete Structure under Uniaxial Compression Based on Peridynamics Modeling
Authors: Shen Feng , Zhang Qing , Huang Dan
Published: October 2013

Peridynamics is a nonlocal formulation of continuum mechanics, which uses integral formulation rather than the spatial partial differential equations. The peridynamic approach avoids using any spatial derivatives, which arise naturally in the classical local theory. It has shown effectiveness and advantage in solving discontinuous problems at both macro- and microscales. In this paper, the peridynamic theory is used to analyze damage and progressive failure of concrete structures. A nonlocal peridynamic model for concrete columns under uniaxial compression is developed. Numerical example illustrates that cracks in a peridynamic body of concrete form spontaneously. The result of the example clarifies the unique advantage of modeling damage accumulation and progressive failure of concrete based on peridynamic theory. This study provides a new promising alternative for analyzing complicated discontinuity problems. Finally, some open problems and future research trends in peridynamics are discussed.
The Departure Characteristics of Traffic Flow at the Signalized Intersection
Authors: Qu Zhaowei , Xing Yan , Hu Hongyu , Duan Yuzhou , Song Xianmin , Chai TingTing , Zhang Hu
Published: October 2013

The motion characteristics of the leading vehicle and the following vehicles of the traffic flow at the typical urban intersections are qualitatively analyzed through the kinematical equation and the traffic wave theory. Then, the motion characteristic of the whole traffic flow during the dispersion process is also studied. Based on the spatiotemporal model of kinematics in the departure process and traffic wave model in the dispersion process proposed, the change of the leading vehicle of the departure process and the time of the following vehicles reaching to the stable speed as well as the relationship between the green time and the departure vehicle number at the intersection are acquired. Furthermore, according to the qualitative analysis and the quantitative calculation of the departure traffic flow at the signalized intersection, the dispersion characteristic of traffic flow at the signalized intersection was studied and analyzed, which provides reliable theoretical basis for traffic signal setting at the intersection.
Comparison between Duncan and Chang’s EB Model and the Generalized Plasticity Model in the Analysis of a High Earth-Rockfill Dam
Authors: Dong Weixin , Hu Liming , Yu Yu Zhen , Lv He
Published: October 2013

Nonlinear elastic model and elastoplastic model are two main kinds of constitutive models of soil, which are widely used in the numerical analyses of soil structure. In this study, Duncan and Chang's EB model and the generalized plasticity model proposed by Pastor, Zienkiewicz, and Chan was discussed and applied to describe the stress-strain relationship of rockfill materials. The two models were validated using the results of triaxial shear tests under different confining pressures. The comparisons between the fittings of models and test data showed that the modified generalized plasticity model is capable of simulating the mechanical behaviours of rockfill materials. The modified generalized plasticity model was implemented into a finite element code to carry out static analyses of a high earth-rockfill dam in China. Nonlinear elastic analyses were also performed with Duncan and Chang's EB model in the same program framework. The comparisons of FEM results andin situmonitoring data showed that the modified PZ-III model can give a better description of deformation of the earth-rockfill dam than Duncan and Chang’s EB model.
Impacts of Cultivated Land Reclamation on the Climate and Grain Production in Northeast China in the Future 30 Years
Authors: Shi Qingling , Lin Yingzhi , Zhang Enpei , Yan Haiming , Zhan Jinyan
Published: October 2013

China, as a large agricultural country as well as a major country with great demand for grain, has played a more and more important role in the international grain market. As Northeast China is one of the major commodity grain bases in China as well as one of the regions with the highest intensity of human activities, it plays an important role in influencing the global food security. This study first generally analyzed the cultivated land reclamation and the climate change of temperature and precipitation in Northeast China during 2000–2010. Then, on the basis of these data, the climatic effects of cultivated land reclamation in Northeast China during 2030–2040 were simulated by the weather research forecast (WRF) model. Finally, the possible effects of the climate change on the grain yield and the potential influence on the food security were analyzed. The simulation result indicated that the temperature in Northeast China would be increasing on the whole, while the precipitation would be decreasing. The result of this study can provide some theoretical support to the agricultural economic development in Northeast China and serve the national macropolicy and food security strategy of the whole China.
On Lipschitz Perturbations of a Self-Adjoint Strongly Positive Operator
Authors: Teodorescu Dinu , Hussain N.
Published: October 2013

In this paper we study semilinear equations of the formAu+λF(u)=f, whereAis a linear self-adjoint operator, satisfying a strong positivity condition, andFis a nonlinear Lipschitz operator. As applications we develop Krasnoselskii and Ky Fan type approximation results for certain pair of maps and to illustrate the usability of the obtained results, the existence of solution of an integral equation is provided.
Numerical Study of Violent Impact Flow Using a CIP-Based Model
Authors: Ji Qiao-ling , Zhao Xi-zeng , Dong Sheng
Published: October 2013

A two-phase flow model is developed to study violent impact flow problem. The model governed by the Navier-Stokes equations with free surface boundary conditions is solved by a Constrained Interpolation Profile (CIP)-based high-order finite difference method on a fixed Cartesian grid system. The free surface is immersed in the computation domain and expressed by a one-fluid density function. An accurate Volume of Fluid (VOF)-type scheme, the Tangent of Hyperbola for Interface Capturing (THINC), is combined for the free surface treatment. Results of another two free surface capturing methods, the original VOF and CIP, are also presented for comparison. The validity and utility of the numerical model are demonstrated by applying it to two dam-break problems: a small-scale two-dimensional (2D) and three-dimensional (3D) full scale simulations and a large-scale 2D simulation. Main attention is paid to the water elevations and impact pressure, and the numerical results show relatively good agreement with available experimental measurements. It is shown that the present numerical model can give a satisfactory prediction for violent impact flow.
Yes, Minister: Reassessing South Africa's Intervention in the Angolan Civil War, 1975–1976
Authors: Miller Jamie
Published: October 2013

In 1975–1976, South Africa's apartheid regime took the momentous step of intervening in the Angolan civil war to counter the Marxist Popular Movement for the Liberation of Angola and its backers in Havana and Moscow. The failure of this intervention and the subsequent ignominious withdrawal had major repercussions for the evolution of the regime and the history of the Cold War in southern Africa. This article is the first comprehensive study of how and why Pretoria became involved. Drawing on a wide variety of primary sources from South African archives as well as interviews with key protagonists, the article shows that the South African Defence Force and Defence Minister P. W. Botha pushed vigorously and successfully for deeper engagement to cope with security threats perceived through the prism of the emerging doctrine of “total onslaught.” South Africa's intervention in Angola was first and foremost the product of strategic calculations derived from a sense of threat perception expressed and experienced in Cold War terms, but applied and developed in a localized southern African context.
Improving Satellite-Based Convective Cloud Growth Monitoring with Visible Optical Depth Retrievals
Authors: Sieglaff Justin M. , Cronce Lee M. , Feltz Wayne F.
Published: October 2013

The use of geostationary satellites for monitoring the development of deep convective clouds has been recently well documented. One such approach, the University of Wisconsin Cloud-Top Cooling Rate (CTC) algorithm, utilizes frequent Geostationary Operational Environmental Satellite (GOES) observations to diagnose the vigor of developing convective clouds through monitoring cooling rates of infrared window brightness temperature imagery. The CTC algorithm was modified to include GOES visible optical depth retrievals for the purpose of identifying growing convective clouds in regions of thin cirrus clouds. An automated objective skill analysis of the two CTC versions (with and without the GOES visible optical depth) versus a variety of Next Generation Weather Radar (NEXRAD) fields was performed using a cloud-object tracking system developed at the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies. The skill analysis was performed in a manner consistent with a recent study employing the same cloud-object tracking system. The analysis indicates that the inclusion of GOES visible optical depth retrievals in the CTC algorithm increases probability of detection and critical success index scores for all NEXRAD fields studied and slightly decreases false alarm ratios for most NEXRAD thresholds. In addition to better identifying vertically growing storms in regions of thin cirrus clouds, the analysis further demonstrates that the strongest cooling rates associated with developing convection are more reliably detected with the inclusion of visible optical depth and that storms that achieve intense reflectivity and large radar-estimated hail exhibit strong cloud-top cooling rates in much higher proportions than they do without the inclusion of visible optical depth.
Simulation of the South Asian Monsoon in a Coupled Model with an Embedded Cloud-Resolving Model
Authors: Krishnamurthy V. , Stan Cristiana , Randall David A. , Shukla Ravi P. , Kinter James L.
Published: October 2013

The simulation of the South Asian monsoon by a coupled ocean–atmosphere model with an embedded cloud-resolving model is analyzed on intraseasonal and interannual time scales. The daily modes of variability in the superparameterized Community Climate System Model, version 3 (SP-CCSM), are compared with those in observation, the superparameterized Community Atmospheric Model, version 3 (SP-CAM3), and the control simulation of CCSM (CT-CCSM) with conventional parameterization of convection. The CT-CCSM fails to simulate the observed intraseasonal oscillations but is able to generate the atmospheric El Niño–Southern Oscillation (ENSO) mode, although with regular biennial variability. The dominant modes of variability extracted from daily anomalies of outgoing longwave radiation, precipitation, and low-level horizontal wind in SP-CCSM consist of two intraseasonal oscillations and two seasonally persisting modes, in good agreement with observation. The most significant observed features of the intraseasonal oscillations correctly simulated by the SP-CCSM are the northward propagation of convection, precipitation, and circulation as well as the eastward and westward propagations. The observed spatial structure and the periods of the oscillations are also well captured by the SP-CCSM, although with lesser magnitude. The SP-CCSM is able to simulate the chaotic variability and spatial structure of the seasonally persisting atmospheric ENSO mode, while the evidence for the Indian Ocean dipole mode is inconclusive. The SP-CAM3 simulates two intraseasonal oscillations and the atmospheric ENSO mode. However, the intraseasonal oscillations in SP-CAM3 do not show northward propagation while their periods and spatial structures are not comparable to observation. The results of this study indicate the necessity of coupled models with sufficiently realistic cloud parameterizations.
Time-dependent diffusion tensor changes of optic nerve in patients with indirect traumatic optic neuropathy
Authors: Li J , Shi W , Li M , Wang Z , He H , Xian J , Lv B , Yan F
Published: October 2013

Background

Indirect traumatic optic neuropathy (ITON) is a devastating cause of permanent visual loss. Axonal degeneration, the characteristic pathological change of ITON, cannot be assessed by conventional imaging. Diffusion tensor imaging (DTI) has been widely used as a sensitive non-invasive imaging technique to obtain information on axonal integrity.

Purpose

To study time-dependent changes in ITON patients with DTI and to provide imaging evidence for clinical diagnosis and therapy.

Material and Methods

We enrolled 28 subjects with unilateral ITON who underwent detailed ocular examinations and magnetic resonance imaging (MRI) examinations. The differences between injured optic nerve (ON) and contralateral ON were tested. The patients were divided into three groups based on time (from injury to examination). Groups 1, 2, and 3 corresponded to the time taken from injury to examination: <7 days, 7–30 days, and >30 days, respectively. DT magnetic resonance imaging (MRI) differences among the groups were compared, including the relationship between diffusion parameters and mean thicknesses of the peripapillary retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) in the macular area.

Results

Compared with contralateral ON, we observed reduced fractional anisotropy (FA) of injured nerves in group 2. Reduced FA and decreased axial diffusivity (λ//) and increased radial diffusivity (λ┴) and mean diffusivity (MD) of injured nerves were observed in group 3. The mean FA value of injured nerves showed a progressive decreasing trend, and mean λ┴ value exhibited a progressive increasing trend. For injured eyes, the MD and λ┴ increases strongly correlated with the decreased mean thicknesses of RNFL and GCC. Conversely, FA was significantly associated with mean RNFL thickness.

Conclusion

DT-MRI parameters could be useful biomarkers in detecting ON changes in ITON patients.
The vision integration process: Applying Rogers’ diffusion of innovations theory to leader–follower communications
Authors: Kohles Jeffrey C , Bligh Michelle C , Carsten Melissa K
Published: October 2013

Involving followers in the communication of a new vision can be critical to its ultimate adoption. Viewing vision as a relatively novel guiding framework that may or may not “diffuse” throughout an organization, we apply Roger’s (2003) Diffusion of Innovations model to the visioning process. Employees from a large supermarket chain (n = 1481) completed surveys concerning vision knowledge, perceptions of the vision’s innovation characteristics (i.e. relative advantage, compatibility, trialability, observability, and complexity), bidirectional leader–follower communication about the vision, perceived integration of the vision into work behaviors, and organizational commitment. Perceptions of the innovation characteristics of the vision were related to both vision integration and commitment. Based on our findings, we argue that a new vision can be conceptualized as an innovation, in which followers are actively involved in decisions of adoption or rejection. We advocate a more balanced approach to vision integration that highlights both leader and follower roles.
The new French 2010 Rabbit Hemorrhagic Disease Virus causes an RHD-like disease in the Sardinian Cape hare (Lepus capensis mediterraneus)
Authors: Puggioni Giantonella , Cavadini Patrizia , Maestrale Caterina , Scivoli Rosario , Botti Giuliana , Ligios Ciriaco , Le Gall-Reculé Ghislaine , Lavazza Antonio , Capucci Lorenzo
Published: October 2013

Lagovirus is an emerging genus of Caliciviridae, which includes the Rabbit Hemorrhagic Disease Virus (RHDV) of rabbits and the European brown hare syndrome virus (EBHSV) of hares that cause lethal hepatitis. In 2010, a new RHDV related virus (RHDV2) with a unique genetic and antigenic profile and lower virulence was identified in France in rabbits. Here we report the identification of RHDV2 as the cause in Sardinia of several outbreaks of acute hepatitis in rabbits and Cape hare (Lepus capensis mediterraneus). This is the first account of a lagovirus that causes fatal hepatitis in both rabbits and hares.
Comparative efficacy of long-acting bronchodilators for COPD - a network meta-analysis
Authors: Cope Shannon , Donohue James F , Jansen Jeroen P , Kraemer Matthias , Capkun-Niggli Gorana , Baldwin Michael , Buckley Felicity , Ellis Alexandra , Jones Paul
Published: October 2013

Background

Clinicians are faced with an increasingly difficult choice regarding the optimal bronchodilator for patients with chronic obstructive pulmonary disease (COPD) given the number of new treatments. The objective of this study is to evaluate the comparative efficacy of indacaterol 75/150/300 μg once daily (OD), glycopyrronium bromide 50 μg OD, tiotropium bromide 18 μg/5 μg OD, salmeterol 50 μg twice daily (BID), formoterol 12 μg BID, and placebo for moderate to severe COPD.

Methods

Forty randomized controlled trials were combined in a Bayesian network meta-analysis. Outcomes of interest were trough and post-dose forced expiratory volume in 1 second (FEV1), St. George’s Respiratory Questionnaire (SGRQ) score and responders (≥4 points), and Transition Dyspnea Index (TDI) score and responders (≥1 point) at 6 months.

Results

Indacaterol was associated with a higher trough FEV1than other active treatments (difference for indacaterol 150 μg and 300 μg versus placebo: 152 mL (95% credible interval (CrI): 126, 179); 160 mL (95% CrI: 133, 187)) and the greatest improvement in SGRQ score (difference for indacaterol 150 μg and 300 μg versus placebo: -3.9 (95% CrI -5.2, -2.6); -3.6 (95% CrI -4.8, -2.3)). Glycopyrronium and tiotropium 18 μg resulted in the next best estimates for both outcomes with minor differences (difference for glycopyrronium versus tiotropium for trough FEV1and SGRQ: 18 mL (95% CrI: -16, 51); -0.55 (95% CrI: -2.04, 0.92).

Conclusion

In terms of trough FEV1and SGRQ score indacaterol, glycopyrronium, and tiotropium are expected to be the most effective bronchodilators.
Long non-coding RNA MEG3 inhibits NSCLC cells proliferation and induces apoptosis by affecting p53 expression
Authors: Lu Kai-hua , Li Wei , Liu Xiang-hua , Sun Ming , Zhang Mei-ling , Wu Wei-qin , Xie Wei-ping , Hou Ya-yi
Published: October 2013

Background

Long non-coding RNAs play an important role in tumorigenesis, hence, identification of cancer-associated lncRNAs and investigation of their biological functions and molecular mechanisms are important for understanding the development and progression of cancer. Recently, the downregulation of lncRNA MEG3 has been observed in various human cancers. However, its role in non-small cell lung cancer (NSCLC) is unknown. The aim of this study was to examine the expression pattern of MEG3 in NSCLC and to evaluate its biological role and clinical significance in tumor progression.

Methods

Expression of MEG3 was analyzed in 44 NSCLC tissues and 7 NSCLC cell lines by qRT-PCR. Over-expression approaches were used to investigate the biological functions of MEG3 in NSCLC cells. Bisulfite sequencing was used to investigate DNA methylation on MEG3 expression. The effect of MEG3 on proliferation was evaluated by MTT and colony formation assays, and cell apoptosis was evaluated by Hoechst staining and Flow-cytometric analysis. NSCLC cells transfected with pCDNA-MEG3 were injection into nude mice to study the effect of MEG3 on tumorigenesis in vivo . Protein levels of MEG3 targets were determined by western blot analysis. Differences between groups were tested for significance using Student’s t-test (two-tailed).

Results

MEG3 expression was decreased in non-small cell lung cancer (NSCLC) tumor tissues compared with normal tissues, and associated with advanced pathologic stage, and tumor size. Moreover, patients with lower levels of MEG3 expression had a relatively poor prognosis. Overexpression of MEG3 decreased NSCLC cells proliferation and induced apoptosis in vitro and impeded tumorigenesis in vivo. MDM2 and p53 protein levels were affected by MEG3 over-expression in vitro.

Conclusions

Our findings indicate that MEG3 is significantly down-regulated in NSCLC tissues that could be affected by DNA methylation, and regulates NSCLC cell proliferation and apoptosis, partially via the activition of p53. Thus, MEG3 may represent a new marker of poor prognosis and is a potential therapeutic target for NSCLC intervention.