bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hierarchically Structured Porous Materials for Energy Conversion and Storage
Authors: Li Yu , Fu Zheng‐Yi , Su Bao‐Lian 
Published: July 2012

AbstractMaterials with hierarchical porosity and structures have been heavily involved in newly developed energy storage and conversion systems. Because of meticulous design and ingenious hierarchical structuration of porosities through the mimicking of natural systems, hierarchically structured porous materials can provide large surface areas for reaction, interfacial transport, or dispersion of active sites at different length scales of pores and shorten diffusion paths or reduce diffusion effect. By the incorporation of macroporosity in materials, light harvesting can be enhanced, showing the importance of macrochannels in light related systems such as photocatalysis and photovoltaics. A state‐of‐the‐art review of the applications of hierarchically structured porous materials in energy conversion and storage is presented. Their involvement in energy conversion such as in photosynthesis, photocatalytic H2 production, photocatalysis, or in dye sensitized solar cells (DSSCs) and fuel cells (FCs) is discussed. Energy storage technologies such as Li‐ions batteries, supercapacitors, hydrogen storage, and solar thermal storage developed based on hierarchically porous materials are then discussed. The links between the hierarchically porous structures and their performances in energy conversion and storage presented can promote the design of the novel structures with advanced properties.
Magnetoresistive Memory with Ultralow Critical Current for Magnetization Switching
Authors: Pertsev Nikolay A. , Kohlstedt Hermann 
Published: July 2012

AbstractThe data writing and thermal stability of information storage are studied theoretically for a magnetic random access memory (MRAM) composed of a magnetic tunnel junction or multilayer exhibiting giant magnetoresistance. The theoretical analysis focuses on the magnetization switching in the “free” layer of a MRAM cell, which is induced by a spin‐polarized current imposing a spin‐transfer torque (STT) on the magnetization. It is shown that the writing current in such an STT‐MRAM reduces dramatically near a spin reorientation transition (SRT) driven by lattice strains and/or surface magnetic anisotropy and even tends to zero under certain conditions. In particular, at the size‐driven SRT in the perpendicular‐anisotropy CoFeB‐MgO tunnel junctions, the critical current densities for magnetization reorientations between the parallel and antiparallel states are expected to fall to low values of about 1.3 × 105 and −3.3 × 104 A cm−2. Remarkably, STT‐MRAMs may combine low writing current with very high thermal stability of information storage (retention over 10 years) even at a high density ≈500 Gbit inch−2.
Cooperative Heterogeneous Organocatalysis and Homogeneous Metal Catalysis for the One‐Pot Regioselective Synthesis of 2‐Pyridones
Authors: Allais Christophe , Baslé Olivier , Grassot Jean‐Marie , Fontaine Maxime , Anguille Stéphane , Rodriguez Jean , Constantieux Thierry 
Published: July 2012

AbstractA direct, one‐pot and regioselective access to N‐alkyl‐ and N‐aryl‐substituted 2‐pyridones is described from readily available β‐keto amides and either primary or secondary propargylic alcohols. This approach involves the combination of two different cooperative homogeneous and heterogeneous catalytic systems based on a transition metal oxide and a supported organocatalyst, respectively.
A qualitative ecological risk assessment of the invasive Nile tilapia, Oreochromis niloticus in a sub‐tropical African river system (Limpopo River, South Africa)
Authors: Zengeya Tsungai A. , Robertson Mark P. , Booth Anthony J. , Chimimba Christian T. 
Published: July 2012

ABSTRACT

This study outlines the development of a qualitative risk assessment method and its application as a screening tool for determining the risk of establishment and spread of the invasive Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), within the central sub‐catchment of the Limpopo River basin in northern South Africa.
The assessment used known physiological tolerance limits of O. niloticus in relation to minimum water temperature, presence or absence of dams, seasonality of river flows, and the presence of indigenous fish species of concern to identify river systems that would be suitable for O. niloticus establishment.
River sections along the Limpopo main river channel and the immediate reaches of its associated tributaries east of the Limpopo/Lephalala river confluence along the Botswana–South Africa–Zimbabwe border were identified as being highly vulnerable to O. niloticus invasion. Rivers in the upper Bushveld catchment (Upper Limpopo, Mogalakwena, Lephalala, Mokolo, Matlabas and Crocodile rivers) were categorized as of medium ecological risk, while headwater streams were considered to be of low ecological risk. The decrease in vulnerability between lowveld and highveld river sections was mainly a function of low water temperatures (8–12°C) associated with increasing altitude.
Oreochromis niloticus is already established in the lower catchment of the Limpopo River basin where indigenous congenerics are at an extinction risk through hybridization and competition exclusion. Oreochromis niloticus, therefore, poses an ecologically unacceptable risk to river systems in the upper catchment where it is yet to establish. The current risk assessment model provides a useful preliminary framework for the identification of river systems that are vulnerable to an O. niloticus invasion where conservation measures should be directed and implemented to prevent its introduction and spread within the Limpopo river system. Copyright © 2012 John Wiley & Sons, Ltd.
Naturally acidic waterways: conceptual food webs for better management and understanding of ecological functioning
Authors: Holland Aleicia , Duivenvoorden Leo J. , Kinnear Susan H. W. 
Published: July 2012

ABSTRACT

Naturally acidic fresh waters have high conservation value, with their habitats supporting a high level of biodiversity as well as providing for rare organisms that are specially adapted to life in low‐pH environments.
Food webs within naturally acidic waterways are heavily reliant on the input of large amounts of organic matter from the surrounding terrestrial environment.
Although these systems are found worldwide, the increasing threats of global climate change and urban developments are placing naturally acidic environments under threat of catastrophic changes to their ecology. Despite this, studies of these unique systems remain in their infancy, especially when compared with systems acidified by anthropogenic means.
This paper aims to explore the varying influences on key food‐web elements in naturally acidic waterways, particularly with regard to allochthonous organic matter (AOM).
A conceptual model for the food webs of naturally acidic environments is presented, with the aim of providing a framework to understand the ecological functioning of these under‐studied systems. This information will be critical in informing management decisions as naturally acidic streams are challenged by increasing environmental pressures.
The possibility that dissolved organic carbon (DOC) can buffer organisms in naturally acidic environments against the toxicity caused by low pH is also explored. Copyright © 2012 John Wiley & Sons, Ltd.
Controllable Synthesis of Nearly Monodisperse Spherical Aggregates of CeO2 Nanocrystals and Their Catalytic Activity for HCHO Oxidation
Authors: Wang Qin , Jia Wenjing , Liu Baocang , Zhao Wenzhi , Li Changyan , Zhang Jun , Xu Gang 
Published: July 2012

AbstractHerein, we report a facile surfactant‐assisted solvothermal synthetic method to prepare nearly monodisperse spherical CeO2 nanocrystals. A good control of the size of CeO2 nanocrystals in the range of 100–500 nm was achieved by simply varying the synthetic parameters such as reaction time, volume ratio of ethanol to water (R), molar ratio of PVP, and concentration of Ce(NO3)3⋅6 H2O in solution. A possible mechanism for the growth of spherical CeO2 nanocrystals is proposed. The obtained CeO2 nanocrystals with a surface area of up to 47 m2g−1 were then employed as a catalyst support. By loading Au‐Pd nanoparticles (about 3 wt. %) onto the CeO2 support, an Au‐Pd/CeO2 catalyst was prepared that exhibited high catalytic activity for HCHO oxidation. At the low temperature of 50 °C, the percentage of HCHO conversion was 100 %, suggesting potential applications in preferential oxidation and other catalytic reactions. These Au‐Pd/CeO2 catalysts may also find applications in indoor formaldehyde decontamination and industrial catalysis. The facile solvothermal method can be extended to the preparation of other metal oxide nanocrystals and provides guidance for size‐ and morphology‐controlled synthesis.
Asynchronous Distributed Algorithms for Heading Consensus of Multi‐Agent Systems with Communication Delay
Authors: Li Qin , Jiang Zhong‐Ping 
Published: July 2012

AbstractIn this paper, we propose two asynchronous distributed protocols for the heading consensus of a multi‐agent group which cannot access a global coordinate system and a global time. Both the leaderless and leader‐following cases are addressed, and inter‐agent communication delay is taken into account. It is proved, under some standard connectivity assumptions, that our leaderless algorithm ensures the heading consensus provided the initial headings are not balanced; and the leader‐based algorithm guarantees the global heading consensus.
Hybrid Model Predictive Power Management of A Fuel Cell‐Battery Vehicle
Authors: Meyer Richard T. , DeCarlo Raymond A , Meckl Peter H. , Doktorcik Chris , Pekarek Steve 
Published: July 2012

AbstractThis paper considers optimal power management of a fuel cell‐battery hybrid vehicle (FCHV) powertrain having three distinct modal configurations (modes): electric motor propelling/battery discharging, propelling/charging, and generating/charging. Each mode has a distinct set of dynamics and constraints. Using component dynamical/algebraic models appropriate to power flow management, the paper develops a supervisory‐level switched system model as an interconnection of subsystems. Given the model, the paper sets forth a hybrid model predictive control strategy based on a minimization of a performance index (PI) that trades off tracking and fuel economy in each operational mode. Specifically, the PI trades off velocity tracking error, battery state of charge variance, and electric drive and hydrogen fuel usages while penalizing frictional braking to encourage regenerative braking. The optimization is performed using an embedded system model and collocation with matlab's fmincon to compute mode switches and continuous time controls. The methodology avoids the computational complexity of alternate approaches based on, e.g., mixed integer programming. Projection methods for approximating the switched system solution from the embedded solution are empirically evaluated. To demonstrate the methodology, an example of a FCHV is simulated using three standard velocity driving profiles: a sawtooth profile with a hill climb, the EPA urban dynamic driving schedule, and the New European Driving Cycle. Also, drive cycle fuel usage is compared to that from the Equivalent Consumption Minimization Strategy.
A Quasi‐Sliding Mode Observer‐based Controller forPMSMDrives
Authors: Corradini M.L. , Ippoliti G. , Longhi S. , Marchei D. , Orlando G. 
Published: July 2012

AbstractIn this paper a quasi‐sliding mode control for a permanent magnet synchronous motor (PMSM) is proposed where a cascade control scheme based on a properly designed state observer provides accurate speed tracking performance. The ultimate boundedness of both the observation error and the speed tracking error is proven. The controller performance has been validated using hardware in the loop (HIL) tests on a simulator based on the model of a commercialPMSMdrive. Tests show that the proposed observer‐based controller produces good speed trajectory tracking performance and it is robust in the presence of disturbances affecting the system.
Time Domain Tuning of Fractional Order Controllers Combined With a Smith Predictor for Automation of Water Distribution in Irrigation Main Channel Pools
Authors: Castillo‐Garcia F.J. , Feliu‐Batlle V. , Rivas‐Perez R. 
Published: July 2012

AbstractThis paper proposes a new technique for designing fractional order controllers applied to the automation of main canal pools of a water irrigation system. As large variation of all the plant parameters is present in such systems, a fractional order family of controllers combined with a Smith Predictor is designed using time domain specifications. The designed controllers are compared with the standard combination of a Smith Predictor with a proportional‐integral (PI) controller. All these controllers are tuned to fulfil the same time specifications in the case of canal nominal dynamics. In some canals the plant parameters may experience large changes that deteriorate the time response, and can even unstabilize the closed‐loop system. The fractional controllers are therefore designed to minimize the loss of performance of the system to variations in these parameters. Simulated results show the performance improvements achieved with these controllers compared with a conventional PI controller.
Robust PID‐PSD Controller Design: BMI Approach
Authors: Veselý Vojtech , Rosinová Danica 
Published: July 2012

AbstractA new robust proportional‐integral‐derivative (PID)–proportional‐sum‐derivative (PSD) controller design method based on linear (bilinear) matrix inequalities (LMI, BMI) is proposed for uncertain affine linear system. The design procedure guarantees the parameter dependent quadratic stability, and guaranteed cost control with a new quadratic cost function (LQRS) including the derivative term for the state vector as a tool to influence the overshoot and response rate. The second approach to the PSD controller design procedure is based on a Lyapunov function with a special term corresponding to the time‐delay part of the control algorithm. The results obtained are illustrated on three examples to show the robust PID, PSD control design procedure and the influence of the choice of matrix S in the extended cost function.
Nonlinear Robust Tracking Control of a Quadrotor UAV on SE(3)
Authors: Lee Taeyoung , Leok Melvin , McClamroch N. Harris 
Published: July 2012

AbstractThis paper provides nonlinear tracking control systems for a quadrotor unmanned aerial vehicle (UAV) that are robust to bounded uncertainties. A mathematical model of a quadrotor UAV is defined on the special Euclidean group, and nonlinear output‐tracking controllers are developed to follow (i) an attitude command, and (ii) a position command for the vehicle center of mass. The controlled system has the desirable properties that the tracking errors are uniformly ultimately bounded, and the size of the ultimate bound can be reduced arbitrarily by control system parameters. Numerical examples illustrating complex maneuvers are provided.
Study of p53 expression and post‐transcriptional modifications after GSM‐900 radiofrequency exposure of human amniotic cells
Authors: Bourthoumieu Sylvie , Magnaudeix Amandine , Terro Faraj , Leveque Philippe , Collin Alice , Yardin Catherine 
Published: July 2012

AbstractThe potential effects of radiofrequency (RF) exposure on the genetic material of cells are very important to determine since genome instability of somatic cells may be linked to cancer development. In response to genetic damage, the p53 protein is activated and can induce cell cycle arrest allowing more time for DNA repair or elimination of damaged cells through apoptosis. The objective of this study was to investigate whether the exposure to RF electromagnetic fields, similar to those emitted by mobile phones of the second generation standard, Global System for Mobile Communications (GSM), may induce expression of the p53 protein and its activation by post‐translational modifications in cultured human cells. The potential induction of p53 expression and activation by GSM‐900 was investigated after in vitro exposure of human amniotic cells for 24 h to average specific absorption rates (SARs) of 0.25, 1, 2, and 4 W/kg in the temperature range of 36.3–39.7 °C. The exposures were carried out using a wire‐patch cell (WPC) under strictly controlled conditions of temperature. Expression and activation of p53 by phosphorylation at serine 15 and 37 were studied using Western blot assay immediately after three independent exposures of cell cultures provided from three different donors. Bleomycin‐exposed cells were used as a positive control. According to our results, no significant changes in the expression and activation of the p53 protein by phosphorylation at serine 15 and 37 were found following exposure to GSM‐900 for 24 h at average SARs up to 4 W/kg in human embryonic cells. Bioelectromagnetics 34:52–60, 2013. © 2012 Wiley Periodicals, Inc.
Determination of p‐Aminobenzenesulfonic acid based on the electrochemiluminescence quenching of tris (2,2’‐bipyridine)‐ ruthenium (II)
Authors: Zhu Yinggui , Li Baojun , Liu Junying , Chen Kun 
Published: July 2012

ABSTRACTThis study describes the quenching effects of p‐aminobenzenesulfonic acid (p‐ABSA) based on electrochemiluminescence (ECL) of the tris (2,2’‐bipyridyl)‐ruthenium(II)(Ru(bpy)32+)/tri‐n‐propylamine (TPrA) system in aqueous solution. Quenching behaviours were observed with a 200‐fold excess of p‐ABSA over Ru(bpy)32+. In the presence of 0.1 M TPrA, the Stern‐Volmer constant (KSV) of ECL quenching was as high as 1.39 × 104 M‐1 for p‐ABSA. The logarithmic plot of inhibited ECL versus concentration of p‐ABSA was linear over the range of 6.0 × 10‐6 ‐3.0 × 10‐4 mol/L. The corresponding limit of detection was 1.2 × 10‐6 mol/L for p‐ABSA (S/N = 3). The mechanism of quenching is believed to involve an energy transfer from the excited‐state luminophore to a dimer of p‐ABSA and the adsorption of free radicals of p‐ABSA at the electrode surface that impeded the oxidation of the Ru(bpy)32+/TPrA system. Copyright © 2012 John Wiley & Sons, Ltd.
Scaffold‐free inkjet printing of three‐dimensional zigzag cellular tubes
Authors: Xu Changxue , Chai Wenxuan , Huang Yong , Markwald Roger R. 
Published: July 2012

AbstractThe capability to print three‐dimensional (3D) cellular tubes is not only a logical first step towards successful organ printing but also a critical indicator of the feasibility of the envisioned organ printing technology. A platform‐assisted 3D inkjet bioprinting system has been proposed to fabricate 3D complex constructs such as zigzag tubes. Fibroblast (3T3 cell)‐based tubes with an overhang structure have been successfully fabricated using the proposed bioprinting system. The post‐printing 3T3 cell viability of printed cellular tubes has been found above 82% (or 93% with the control effect considered) even after a 72‐h incubation period using the identified printing conditions for good droplet formation, indicating the promising application of the proposed bioprinting system. Particularly, it is proved that the tubular overhang structure can be scaffold‐free fabricated using inkjetting, and the maximum achievable height depends on the inclination angle of the overhang structure. As a proof‐of‐concept study, the resulting fabrication knowledge helps print tissue‐engineered blood vessels with complex geometry. Biotechnol. Bioeng. 2012; 109: 3152–3160. © 2012 Wiley Periodicals, Inc.
Comparison of CO2 and bicarbonate as inorganic carbon sources for triacylglycerol and starch accumulation in Chlamydomonas reinhardtii
Authors: Gardner Robert D. , Lohman Egan , Gerlach Robin , Cooksey Keith E. , Peyton Brent M. 
Published: July 2012

AbstractMicroalgae are capable of accumulating high levels of lipids and starch as carbon storage compounds. Investigation into the metabolic activities involved in the synthesis of these compounds has escalated since these compounds can be used as precursors for food and fuel. Here, we detail the results of a comprehensive analysis of Chlamydomonas reinhardtii using high or low inorganic carbon concentrations and speciation between carbon dioxide and bicarbonate, and the effects these have on inducing lipid and starch accumulation during nitrogen depletion. High concentrations of CO2 (5%; v/v) produced the highest amount of biofuel precursors, transesterified to fatty acid methyl esters, but exhibited rapid accumulation and degradation characteristics. Low CO2 (0.04%; v/v) caused carbon limitation and minimized triacylglycerol (TAG) and starch accumulation. High bicarbonate caused a cessation of cell cycling and accumulation of both TAG and starch that was more stable than the other experimental conditions. Starch accumulated prior to TAG and then degraded as maximum TAG was reached. This suggests carbon reallocation from starch‐based to TAG‐based carbon storage. Biotechnol. Bioeng. 2013; 110: 87–96. © 2012 Wiley Periodicals, Inc.
The microalga Parachlorella kessleri––A novel highly efficient lipid producer
Authors: Li Xiuling , Přibyl Pavel , Bišová Kateřina , Kawano Shigeyuki , Cepák Vladislav , Zachleder Vilém , Čížková Mária , Brányiková Irena , Vítová Milada 
Published: July 2012

AbstractThe alga Parachlorella kessleri, strain CCALA 255, grown under optimal conditions, is characterized by storage of energy in the form of starch rather than lipids. If grown in the complete medium, the cultures grew rapidly, producing large amounts of biomass in a relatively short time. The cells, however, contained negligible lipid reserves (1–10% of DW). Treatments inducing hyperproduction of storage lipids in P. kessleri biomass were described. The cultures were grown in the absence or fivefold decreased concentration of either nitrogen or phosphorus or sulfur. Limitation by all elements using fivefold or 10‐fold diluted mineral medium was also tested. Limitation with any macroelement (nitrogen, sulfur, or phosphorus) led to an increase in the amount of lipids; nitrogen limitation was the most effective. Diluted nutrient media (5‐ or 10‐fold) were identified as the best method to stimulate lipid overproduction (60% of DW). The strategy for lipid overproduction consists of the fast growth of P. kessleri culture grown in the complete medium to produce sufficient biomass (DW more than 10 g/L) followed by the dilution of nutrient medium to stop growth and cell division by limitation of all elements, leading to induction of lipid production and accumulation up to 60% DW. Cultivation conditions necessary for maximizing lipid content in P. kessleri biomass generated in a scale‐up solar open thin‐layer photobioreactor were described. Biotechnol. Bioeng. 2013; 110: 97–107. © 2012 Wiley Periodicals, Inc.
Bio‐based production of C2–C6 platform chemicals
Authors: Jang Yu‐Sin , Kim Byoungjin , Shin Jae Ho , Choi Yong Jun , Choi Sol , Song Chan Woo , Lee Joungmin , Park Hye Gwon , Lee Sang Yup 
Published: July 2012

AbstractPlatform chemicals composed of 2–6 carbons derived from fossil resources are used as important precursors for making a variety of chemicals and materials, including solvents, fuels, polymers, pharmaceuticals, perfumes, and foods. Due to concerns regarding our environment and the limited nature of fossil resources, however, increasing interest has focused on the development of sustainable technologies for producing these platform chemicals from renewable resources. The techniques and strategies for developing microbial strains for chemicals production have advanced rapidly, and it is becoming feasible to develop microbes for producing additional types of chemicals, including non‐natural molecules. In this study, we review the current status of the bio‐based production of major C2–C6 platform chemicals, focusing on the microbial production of platform chemicals that have been used for the production of chemical intermediates, building block compounds, and polymers. Biotechnol. Bioeng. 2012; 109: 2437–2459. © 2012 Wiley Periodicals, Inc.