bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability Properties of Switched Nonlinear Delay Systems with Synchronous or Asynchronous Switching
Authors: Wang Yue‐E , Sun Xi‐Ming , Wang Wei , Zhao Jun 
Published: October 2014

AbstractThis paper is concerned with the problem of input‐to‐state stability (ISS) for a class of switched nonlinear delay systems. The cases where the switching signal of the system and the switching signal of the corresponding controller are synchronous and asynchronous are both considered. To study two asynchronous switching signals in a unified framework, we adopt the technique of the merging switching signal. Based on a piecewise Lyapunov–Krasovskii functional method, some sufficient conditions are explicitly given to guarantee the ISS of the switched nonlinear delay system under the average dwell time scheme. Finally, a numerical example is presented to demonstrate the effectiveness of the proposed theory.
Bioenergy in Mexico: Status and perspective
Authors: Alemán‐Nava Gibrán S. , Meneses‐Jácome Alexander , Cárdenas‐Chávez Diana L. , Díaz‐Chavez Rocío , Scarlat Nicolae , Dallemand Jean‐Francois , Ornelas‐Soto Nancy , García‐Arrazola Roeb , Parra Roberto 
Published: October 2014

AbstractMexico's government has introduced a Law on Climate Change that is unique worldwide; it establishes targets for greenhouse gases reductions at the same level of developed countries despite being an emerging country. This reform represents a crucial challenge for the electrical and transport sectors largely dependent on fossil energy since Mexico is the ninth‐largest oil producer in the world. Local industry and academic sectors are called to lead the introduction of renewable energy sources, and particularly to enhance the share of energy from biomass in the local energy basket. Thus, this paper outlines the baseline on regulatory, energy, and carbon markets, and the scientific capacity to increase bioenergy utilization in Mexico. Furthermore, it opens a discussion about the steps forward with regard to sustainability and research needs, emphasizing some priorities and principles to develop a bioenergy system environmentally compatible in this country. © 2014 The Authors. Biofuels, Bioproducts, Biorefining published by Society of Chemical Industry and John Wiley & Sons, Ltd.
Ge‐Mediated Modification in Ta3N5 Photoelectrodes with Enhanced Charge Transport for Solar Water Splitting
Authors: Feng Jianyong , Cao Dapeng , Wang Zhiqiang , Luo Wenjun , Wang Jiajia , Li Zhaosheng , Zou Zhigang 
Published: October 2014

AbstractTa3N5 is a promising photoanode candidate for photoelectrochemical water splitting, with a band gap of about 2.1 eV and a theoretical solar‐to‐hydrogen efficiency as high as 15.9 % under AM 1.5 G 100 mW cm−2 irradiation. However, the presently achieved highest photocurrent (ca. 7.5 mA cm−2) on Ta3N5 photoelectrodes under AM 1.5 G 100 mW cm−2 is far from the theoretical maximum (ca. 12.9 mA cm−2), which is possibly due to serious bulk recombination (poor bulk charge transport and charge separation) in Ta3N5 photoelectrodes. In this study, we show that volatilization of intentionally added Ge (5 %) during the synthesis of Ta3N5 promotes the electron transport and thereby improves the charge‐separation efficiency in bulk Ta3N5 photoanode, which affords a 320 % increase of the highest photocurrent comparing with that of pure Ta3N5 photoanode under AM 1.5 G 100 mW cm−2 simulated sunlight.
Synthesis, Properties, and n‐Type Transistor Characteristics of π‐Conjugated Compounds Having a Carbonyl‐Bridged Thiazole‐Fused Polycyclic System
Authors: Ie Yutaka , Sato Chihiro , Nitani Masashi , Tada Hirokazu , Aso Yoshio 
Published: October 2014

AbstractA series of electron‐deficient π‐conjugated systems with 4,9‐dihydro‐s‐indaceno[2,1‐d:6,5‐d′]dithiazole‐4,9‐dione‐based structures and fluorinated acyl groups as the terminal units have been designed and synthesized for application as organic field‐effect transistor (OFET) materials. The thermal, photophysical, and electrochemical properties and OFET performance of the synthesized compounds were investigated. OFET evaluation revealed that all compounds exhibited typical electron‐transporting characteristics, and electron mobilities up to 0.26 cm2 V−1 s−1 could be achieved. The air stabilities of OFET operation were dependent on the nature of the compounds and were investigated by X‐ray diffraction and atomic force microscopy. The terminal units had a great influence not only on the molecular properties, but also on the film‐forming properties and OFET performance.
Expedient Synthesis of Chiral α‐Amino Acids through Nickel‐Catalyzed Reductive Cross‐Coupling
Authors: Lu Xi , Yi Jun , Zhang Zhen‐Qi , Dai Jian‐Jun , Liu Jing‐Hui , Xiao Bin , Fu Yao , Liu Lei 
Published: October 2014

AbstractA novel method for the synthesis of non‐natural L‐ and D‐amino acids by a Ni‐catalyzed reductive cross‐coupling reaction is described. This strategy enables the racemization‐free cross‐coupling of serine/homoserine‐ derived iodides with aryl/acyl/alkyl halides. It provides convenient access to varieties of enantiopure and functionalized amino acids, which are important building blocks in bioactive compounds and pharmaceuticals.
Modelling of gradual internal reforming process over Ni‐YSZ SOFC anode with a catalytic layer
Authors: Girona Kelly , Sailler Sébastien , Gélin Patrick , Bailly Nicolas , Georges Samuel , Bultel Yann 
Published: October 2014

AbstractMethane appears to be a fuel of great interest for solid oxide fuel cell (SOFC) systems because it can be directly converted into hydrogen by Internal Reforming within the SOFC anode. To cope with carbon formation, a new SOFC cell configuration combining a catalyst layer with a classical anode was developed. The rate of the CH4 consumption in the catalyst layer (Ir‐CGO) was determined experimentally for small values of steam to carbon ratios. This paper proposes a modelling and a simulation, using the CFD‐Ace software package, of the behaviour of a SOFC operated in Gradual Internal Reforming (GIR) conditions. This model of SOFC takes into account the kinetics of the steam reforming reaction in the catalyst layer in order to assess the influence of the steam to carbon ratio and the cell polarization. Because the risk of carbon formation is greater under GIR operation, a detailed thermodynamic analysis was carried out. Thermodynamic equilibrium calculations allowed us to predict the conditions of carbon formation occurrence.
Analysis of incomplete longitudinal data with informative drop‐out and outliers
Authors: Sinha Sanjoy K. , Sattar Abdus 
Published: October 2014

AbstractThis article proposes and explores a robust method for analysing longitudinal continuous responses with informative drop‐outs. The robust method, developed in the framework of the maximum likelihood, is useful for bounding the influence of potential outliers when analysing the data. The asymptotic properties of the robust estimators are discussed. The empirical properties are investigated in simulations. An application is provided using longitudinal measurements on a biomarker of sepsis being studied for understanding the progression of pneumonia to severe sepsis in a group of patients.The Canadian Journal of Statistics42: 670–695; 2014 © 2014 Statistical Society of Canada
Secure and efficient data‐sharing in clouds
Authors: Zhang Jiang , Zhang Zhenfeng 
Published: October 2014

SummaryWith the rapid development of cloud computing, cloud storage has become a cost‐effective solution for many users with the demand of data storage. However, there are still two main concerns for users with sensitive/private data: (1) Is it secure to store private data in public cloud storages? (2) Is there an efficient way to share private data with other specified users? In the past years, several papers in the literature have used proxy re‐encryption (PRE) to address these two concerns, where the efficiency of the underlying PRE scheme is usually a bottleneck of the overall performance of cloud storages. In this paper, we dedicate to design a secure and practical PRE scheme for cloud‐based data‐sharing. First, we discuss a ‘pitfall’ in the security proof of several existing PREs. Then, we give a general framework for proving the chosen ciphertext attacks (CCA) security of single‐hop unidirectional PRE schemes. Finally, we propose a practical PRE scheme that is proven secure against CCA under the computational Diffie–Hellman problem in the random oracle model. We evaluate the performance of our PRE scheme both in theoretical comparisons with related schemes and in implementations at several security levels. The results indicate that our scheme can be practical in cloud‐based data‐sharing. Copyright © 2014 John Wiley & Sons, Ltd.
Honeybee nutrition is linked to landscape composition
Authors: Donkersley Philip , Rhodes Glenn , Pickup Roger W. , Jones Kevin C. , Wilson Kenneth 
Published: October 2014

AbstractDeclines in insect pollinators in Europe have been linked to changes in land use. Pollinator nutrition is dependent on floral resources (i.e., nectar and pollen), which are linked to landscape composition. Here, we present a stratified analysis of the nutritional composition of beebread in managed honeybee hives with a view to examining potential sources of variation in its nutritional composition. Specifically, we tested the hypothesis that beebread composition correlates with local land use and therefore available floral resources. The results demonstrated that the starch, lipid, and moisture contents of beebread are all highly conserved across hives, whereas levels of protein and nonreducing sugar increased as the year progressed, reducing sugars, however, decreased during the first half of the year and then increased toward the end. Local land use around hives was quantified using data from the Countryside Survey 2007 Land Cover Map. Bee‐bread protein content was negatively correlated with increasing levels of arable and horticultural farmland surrounding hives and positively correlated with the cover of natural grasslands and broadleaf woodlands. Reducing sugar content was also positively correlated with the amount of broad‐leaved woodland in a 3 Km² radius from the hives. Previous studies on a range of invertebrates, including honeybees, indicate that dietary protein intake may have a major impact on correlates of fitness, including longevity and immune function. The finding that beebread protein content correlates with land use suggests that landscape composition may impact on insect pollinator well‐being and provides a link between landscape and the nutritional ecology of socially foraging insects in a way not previously considered.
Analysis of Japan's Long‐Term Energy Outlook Considering Massive Deployment of Variable Renewable Energy under Nuclear Energy Scenario
Authors: Komiyama Ryoichi , Fujii Yasumasa 
Published: October 2014

SUMMARYThis paper investigates Japan's long‐term energy outlook to 2050 taking into consideration the massive deployment of solar photovoltaic (PV) systems and wind power generation under a nuclear energy scenario. The extensive introduction of PV systems and wind power systems is expected to play an important role in enhancing electricity supply security after the Fukushima nuclear power accident, which has increased the uncertainty of the future additional construction of nuclear power plants in Japan. Against this background, we develop an integrated energy assessment model composed of both an econometric energy demand and supply model and an optimal power generation mix model. The latter model is able to explicitly analyze the impact of output fluctuations for various renewable energy sources at a detailed time resolution of 10 min on 365 consecutive days, incorporating the role of stationary battery technology. The simulation results reveal that intermittent fluctuations derived from a high penetration level of those renewables are controlled by quick load following operation by natural gas combined cycle power plants, pumped‐storage hydro power, stationary battery technology, and output suppression of PV and wind power generation. The results show as well that massive penetration of renewables does not necessarily require a comparable scale of stationary battery capacity. Additionally, in the scenario, which assumes the decommissioning of nuclear power plants with a lifetime of over 40 years, the required PV capacity in 2050 amounts to more than double the PV installation potential in both buildings and abandoned farmland areas.
Fundamental Theories on a Combined Energy Cycle of an Electrostatic Induction Hydrogen Electrolytic Cell and Fuel Cell to Produce Fully Sustainable Hydrogen Energy
Authors: Ono Katsutoshi 
Published: October 2014

SUMMARYA hydrogen electrolyzer for decomposition of stable compound H2O is essentially an electronic device that uses mainly electrostatic‐to‐chemical energy conversion to produce a stoichiometric H2+O2 fuel. To achieve a breakthrough in the practical hydrogen electrolytic cell, we demonstrate the electrostatic induction potential superposed electrolyzer. This system operates on a mechanism in which, on a theoretical basis, the power used is 17% of the total electrical energy required, while the remaining 83% can be provided by electrostatic energy free of power. Because H2O is placed in its decomposition state in the electrostatic field where no current flows, the decomposition voltage is identified as a barrier potential that the electrolytic current must overcome by expending the major part of the total system power. The potential superposition method for supplying energy to the cell was found to avoid the barrier potential effect within the laws of thermodynamics. Combining a fuel cell for producing power from pure H2 and O2 in stoichiometric proportions with this type of hydrogen electrolytic cell in a closed energy cycle can achieve a highly positive H2 balance.
Gas Heating and Formation of Single Linear Discharge Channel on Repetitive Branched Streamer Corona
Authors: Matsumoto Takao , Kijima Koji , Shimoju Toshiharu , Inada Yoichi , Izawa Yasuji , Nishijima Kiyoto 
Published: October 2014

SUMMARYUnder a nonuniform field in an atmospheric short gap, a branched pulse streamer corona changes to a single filamentary discharge (SFD) for a split second just before sparkover occurs. This SFD is a pretransitional phenomenon of sparkover. Therefore, it is very important to study SFD for an understanding of the sparkover mechanism. In this work, the SFD was recreated well by applying a highly repetitive impulse voltage to a needle‐plane gap in synthetic air with dilute CO2. The characteristics of the SFD, including the channel temperature, the propagation of the streamer head, and the formation process, were investigated by means of an intensified charge coupled‐device (ICCD) camera and a spectroscopic measurement system. It was found that the transition to SFD progresses with localized gas heating along the discharge channel. Furthermore, it was revealed that the SFD is a nonbranched positive streamer.
Iron Loss Calculation of AC Filter Inductor for Three‐Phase PWM Inverters
Authors: Matsumori Hiroaki , Shimizu Toshihisa , Takano Koushi , Ishii Hitoshi 
Published: October 2014

SUMMARYIn recent years, remarkable advancement of new power semiconductor devices, such as SiC and GaN, enables the increase of switching frequency of power converters, and hence the volume of passive components, such as ac filters and transformers, can be reduced. However, temperature rise caused by the inductor loss is increasing, and hence iron loss evaluation of the inductor is one of the most important issues to realize high power density converters. Conventionally, an improved generalized Steinmetz equation (iGSE) has proposed in order to calculate the iron loss under a pulse voltage magnetizing condition. However, accurate iron loss calculation of the ac filter inductor used in a PWM inverter cannot be realized. The authors have proposed two methods of iron loss evaluation of ac filter inductors. The first one is a loss map method which can calculate the iron loss without using a real PWM inverter. Another one is an ILA (Inductor Loss Analyzer) which can measure the iron loss in every switching period in a real PWM inverter. In this paper, comparisons of the iron loss between the ILA and the loss map method on both the single‐phase and three‐phase inverters are studied. It is found that iron loss of the ac filter inductor in the three‐phase PWM inverter which is calculated by the loss map method cause a large error on a specific condition. In order to prevent the calculation error, the authors proposed a revised loss map method and proved the effectiveness of the method.
Stability analysis of MDOF real‐time dynamic hybrid testing systems using the discrete‐time root locus technique
Authors: Zhu Fei , Wang Jin‐Ting , Jin Feng , Chi Fu‐Dong , Gui Yao 
Published: October 2014

SUMMARYThe time delay resulting from the servo hydraulic systems can potentially destabilize the real‐time dynamic hybrid testing (RTDHT) systems. In this paper, the discrete‐time root locus technique is adopted to investigate the delay‐dependent stability performance of MDOF RTDHT systems. Stability analysis of an idealized two‐story shear frame with two DOFs is first performed to illustrate the proposed method. The delay‐dependent stability condition is presented for various structural properties, time delay, and integration time steps. Effects of delay compensation methods on stability are also investigated. Then, the proposed method is applied to analyze the delay‐dependent stability of a single shaking table RTDHT system with an 18‐DOF finite element numerical substructure, and corresponding RTDHTs are carried out to verify the theoretical results. Furthermore, the stability behavior of a finite element RTDHT system with two physical substructures, loaded by twin shaking tables, is theoretically and experimentally investigated. All experimental results convincingly demonstrate that the delay‐dependent stability analysis on the basis of the discrete‐time root locus technique is feasible. Copyright © 2014 John Wiley & Sons, Ltd.
Quantitative failure metric for gravity dams
Authors: Hariri‐Ardebili M. A. , Saouma V. 
Published: October 2014

SummaryQuantitative failure monitoring is a critical tool for safety assessment of concrete dams. This includes damage occurrence, intensity, location, number, size, and propagation pattern. Such an assessment is essential for a quantifiable prioritization of repair and will thus reduce overall cost and improve safety. This paper will address this timely topic through the nonlinear transient analysis of a dam and failure will be ascertained through a multi‐scale damage index. A damage‐plastic model for mass concrete is used, Drucker‐Prager elasto‐plastic one for the foundation, and infinite elements are used for far‐field boundaries. Water‐dam interaction is accounted for through fluid finite elements. It is determined that the proposed damage indices can indeed provide a quantitative metric for the degree of failure in gravity dams in terms of the input dynamic motion. Copyright © 2014 John Wiley & Sons, Ltd.
Evaluation of seismic behaviour of Cheomseongdae using dynamic centrifuge model test
Authors: Park Heon‐Joon , Kim Dong‐Soo 
Published: October 2014

SummaryCheomseongdae is known to be the oldest astronomical observatory in Asia. According to historical records, the Gyeongju area, where Cheomseongdae is located, suffered from numerous medium‐scale earthquakes. Cheomseongdae has a masonry structure, which is apparently vulnerable to horizontal dynamic loads such as earthquakes. However, despite its appearance, features such as the filler of the lower half, inner irregular‐shaped stones which can induce high frictional resistance, eight long horizontal tie stones inside the artefact, and a grid of interlocking headstones increase its resistance to horizontal dynamic loads. Dynamic centrifuge model tests were performed on Cheomseongdae in order to evaluate the seismic response characteristics of this architectural heritage structure. Model tests were executed on two 1/15‐scale models: one which was an exact duplicate of the original Cheomseongdae and the other without the long horizontal tie stones and grid of interlocking headstones. On the basis of the amplification patterns in the time and frequency domains, the differences in seismic behaviour between the two Cheomseongdae models, and a broken stone at the 19th layer during tests, the long horizontal tie stones and headstones were found to increase the seismic resistance within Cheomseongdae and provide a glimpse of the ‘seismic design’ of our ancestors. Copyright © 2014 John Wiley & Sons, Ltd.
Efficient Bayesian sensor placement algorithm for structural identification: a general approach for multi‐type sensory systems
Authors: Yuen Ka‐Veng , Kuok Sin‐Chi 
Published: October 2014

SummaryIn this paper, a Bayesian sequential sensor placement algorithm, based on the robust information entropy, is proposed for multi‐type of sensors. The presented methodology has two salient features. It is a holistic approach such that the overall performance of various types of sensors at different locations is assessed. Therefore, it provides a rational and effective strategy to design the sensor configuration, which optimizes the use of various available resources. This sequential algorithm is very efficient due to its Bayesian nature, in which prior distribution can be incorporated. Therefore, it avoids the possible unidentifiability problem encountered in a sequential process, which starts with small number of sensors. The proposed algorithm is demonstrated using a shear building and a lattice tower with consideration of up to four types of sensors. Copyright © 2014 John Wiley & Sons, Ltd.
A multi‐dimensional analysis of pro‐glacial landscape change at Sólheimajökull, southern Iceland
Authors: Staines Kate E. H. , Carrivick Jonathan L. , Tweed Fiona S. , Evans Andrew J. , Russell Andrew J. , Jóhannesson Tómas , Roberts Matthew 
Published: October 2014

AbstractPro‐glacial landscapes are some of the most active on Earth. Previous studies of pro‐glacial landscape change have often been restricted to considering either sedimentological, geomorphological or topographic parameters in isolation and are often mono‐dimensional. This study utilized field surveys and digital elevation model (DEM) analyses to quantify planform, elevation and volumetric pro‐glacial landscape change at Sólheimajökull in southern Iceland for multiple time periods spanning from 1960 to 2010. As expected, the most intense geomorphological changes persistently occurred in the ice‐proximal area. During 1960 to 1996 the pro‐glacial river was relatively stable. However, after 2001 braiding intensity was higher, channel slope shallower and there was a shift from overall incision to aggradation. Attributing these pro‐glacial river channel changes to the 1999 jökulhlaup is ambiguous because it coincided with a switch from a period of glacier advance to that of glacier retreat. Furthermore, glacier retreat (of ~40 m yr−1) coincided with ice‐marginal lake development and these two factors have both altered the pro‐glacial river channel head elevation. From 2001 to 2010 progressive increase in channel braiding and progressive downstream incision occurred; these together probably reflecting stream power due to increased glacier ablation and reduced sediment supply due to trapping of sediment by the developing ice‐marginal lake. Overall, this study highlights rapid spatiotemporal pro‐glacial landscape reactions to changes in glacial meltwater runoff regimes, glacier terminus position, sediment supply and episodic events such as jökuhlaups. Recognizing the interplay of these controlling factors on pro‐glacial landscapes will be important for understanding the geological record and for landscape stability assessments. Copyright © 2014 John Wiley & Sons, Ltd.