Home About us Contact
|
Home About us Contact | ||
|
|
||
Storage Devices (storage + device)
Selected AbstractsC60 Nanostructures for Applications in Information Technology,ADVANCED ENGINEERING MATERIALS, Issue 4 2009Oliver Senftleben Carbon nanostructures,such as nanotubes, fullerenes, or graphene sheets,are studied widely in search of future applications in electronic devices. In our work, we demonstrate the possibility of embedding C60 fullerene molecules into a crystalline silicon matrix to form highly confined carbon- , -layers as well as into an amorphous SiO2 gate stack for possible application as a charge storage device. [source] Energy Saving Speed and Charge/Discharge Control of a Railway Vehicle with On-board Energy Storage by Means of an Optimization ModelIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 6 2009Masafumi Miyatake Member Abstract The optimal operation of rail vehicle minimizing total energy consumption is discussed in this paper. In recent years, the energy storage devices have enough energy and power density to use in trains as on-board energy storage. The on-board storage can assist the acceleration/deceleration of the train and may decrease energy consumption. Many works on the application of the energy storage devices to trains were reported, however, they did not deal enough with the optimality of the control of the devices. The authors pointed out that the charging/discharging command and vehicle speed profile should be optimized together based on the optimality analysis. The authors have developed the mathematical model based on a general optimization technique, sequential quadratic programming. The proposed method can determine the optimal acceleration/deceleration and current commands at every sampling point under fixed conditions of transfer time and distance. Using the proposed method, simulations were implemented in some cases. The electric double layer capacitor (EDLC) is assumed as an energy storage device in our study, because of its high power density etc. The trend of optimal solutions such as values of control inputs and energy consumption is finally discussed. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Synthesis of Cobalt/Polymer Multilayer Nanotubes,ADVANCED ENGINEERING MATERIALS, Issue 4 2005K. Nielsch Cobalt/polymer multilayer nanotubes (see Figure) are formed by wetting of alumina and silicon membranes by polystyrene containing a metallo,organic precursor, followed by a thermal decomposition process. This article describes the fabrication and magnetic properties of high quality, thin-walled ferromagnetic nanotubes. They might be very attractive for a broad range of potential applications ranging from biotechnology to magnetic storage devices. [source] Optimization of Train Speed Profile for Minimum Energy ConsumptionIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2010Masafumi Miyatake Member Abstract The optimal operation of railway systems minimizing total energy consumption is discussed in this paper. Firstly, some measures of finding energy-saving train speed profiles are outlined. After the characteristics that should be considered in optimizing train operation are clarified, complete optimization based on optimal control theory is reviewed. Their basic formulations are summarized taking into account most of the difficult characteristics peculiar to railway systems. Three methods of solving the formulation, dynamic programming (DP), gradient method, and sequential quadratic programming (SQP), are introduced. The last two methods can also control the state of charge (SOC) of the energy storage devices. By showing some numerical results of simulations, the significance of solving not only optimal speed profiles but also optimal SOC profiles of energy storage are emphasized, because the numerical results are beyond the conventional qualitative studies. Future scope for applying the methods to real-time optimal control is also mentioned. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Energy Saving Speed and Charge/Discharge Control of a Railway Vehicle with On-board Energy Storage by Means of an Optimization ModelIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 6 2009Masafumi Miyatake Member Abstract The optimal operation of rail vehicle minimizing total energy consumption is discussed in this paper. In recent years, the energy storage devices have enough energy and power density to use in trains as on-board energy storage. The on-board storage can assist the acceleration/deceleration of the train and may decrease energy consumption. Many works on the application of the energy storage devices to trains were reported, however, they did not deal enough with the optimality of the control of the devices. The authors pointed out that the charging/discharging command and vehicle speed profile should be optimized together based on the optimality analysis. The authors have developed the mathematical model based on a general optimization technique, sequential quadratic programming. The proposed method can determine the optimal acceleration/deceleration and current commands at every sampling point under fixed conditions of transfer time and distance. Using the proposed method, simulations were implemented in some cases. The electric double layer capacitor (EDLC) is assumed as an energy storage device in our study, because of its high power density etc. The trend of optimal solutions such as values of control inputs and energy consumption is finally discussed. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Energy Saving and Environmental Measures in Railway Technologies: Example with Hybrid Electric Railway VehiclesIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 1 2008Masamichi Ogasa Member Abstract The electric railway system is the highest class of energy efficient transportation means. This is due to two important points: (i) low running resistance (including low energy losses) and (ii) energy regeneration in braking. Regenerative braking of railway electric vehicles is effective when the other powering ones, in other words electrical load, exist near the regenerating train on the same electrified line. So, early in the morning and at midnight, or in the low-density district lines, regeneration cancellation phenomenon often occurs and the regenerative brake force cannot be operated in accordance with the recommended value. Newly appeared high-performance energy storage devices press the issues of energy storage and reuse technologies on ground and on vehicles. Hybrid energy source is one effective solution. In this paper, as an example, we show our trolley and on-board battery hybrid controlled tramcar, developed to reduce regeneration cancellation. With the trolley line collective power as well as charge and discharge power of the on-board lithium ion rechargeable battery, the hybrid energy providing and regenerating technology is achieved. The running test results show a maximum regenerative ratio of 44%, which is top class value in an electric railway system. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Multibit Storage of Organic Thin-Film Field-Effect TransistorsADVANCED MATERIALS, Issue 19 2009Yunlong Guo Organic thin-film field-effect transistor (OTFT) multibit storage devices are fabricated based on pentacene or copper phthalocyaine (CuPc) with normal polymer modifying layers of polystyrene (PS) or polymethylmethacrylate (PMMA). The devices shows excellent multibit storage properties in a single OTFT using electric and light-assisted programs. [source] Financial costs and environmental impact optimization of the energy supply systemsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2002L. I. González-Monroy Abstract We have designed and implemented a tool to evaluate and optimize energy supply systems, so that the financial costs, the consumption of primary energy or the amount of harmful emission to the environment are minimized. We have set-up a general description of these systems and have applied a heuristic optimization method, Simulated Annealing, that allows us, in an efficient way, to determine the best way to fulfil different types of energy demand using a set of facilities of energy transformation and storage. We have also considered the time correlation introduced by the storage devices or transport processes and the possible behaviour of the system when the external conditions (fuel prices, demand profiles, etc.) change. Copyright © 2002 John Wiley & Sons, Ltd. [source] Automated application component placement in data centers using mathematical programmingINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 6 2008Xiaoyun Zhu In this article we address the application component placement (ACP) problem for a data center. The problem is defined as follows: for a given topology of a network consisting of switches, servers and storage devices with varying capabilities, and for a given specification of a component-based distributed application, decide which physical server should be assigned to each application component, such that the application's processing, communication and storage requirements are satisfied without creating bottlenecks in the infrastructure, and that scarce resources are used most efficiently. We explain how the ACP problem differs from traditional task assignment in distributed systems, or existing grid scheduling problems. We describe our approach of formalizing this problem using a mathematical optimization framework and further formulating it as a mixed integer program (MIP). We then present our ACP solver using GAMS and CPLEX to automate the decision-making process. The solver was numerically tested on a number of examples, ranging from a 125-server real data center to a set of hypothetical data centers with increasing size. In all cases the ACP solver found an optimal solution within a reasonably short time. In a numerical simulation comparing our solver to a random selection algorithm, our solver resulted in much more efficient use of scarce network resources and allowed more applications to be placed in the same infrastructure. Copyright © 2008 John Wiley & Sons, Ltd. [source] Content storage architectures for boosted IPTV serviceBELL LABS TECHNICAL JOURNAL, Issue 3 2008Marc Verhoeyen Television (TV) consumers adore interactivity and personalization. Internet Protocol television (IPTV) systems help satisfy this desire by providing different services including video-on-demand (VoD), network personal video recording (NPVR), and time shift TV (TSTV). However, these services place a heavy traffic load on the network by requiring a unicast video stream for each active customer. This paper discusses means to reduce the network traffic load by introducing storage deep in the network-thus avoiding the need for unicast traffic support over the metro or core network-and algorithms to place content intelligently on those storage devices. An algorithm for intelligent redistribution is described that endeavors to place the most appropriate content close to consumers. The paper discusses further how this new paradigm of network storage can help improve quality of experience for the IPTV consumer and can assist in the deployment of Internet video and sharing of user-generated content (UGC). © 2008 Alcatel-Lucent. [source] Cyclic Quaternary Ammonium Ionic Liquids with Perfluoroalkyltrifluoroborates: Synthesis, Characterization, and PropertiesCHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2006Zhi-Bin Zhou Dr. Abstract New cyclic quaternary ammonium salts, composed of N -alkyl(alkyl ether)- N -methylpyrrolidinium, -oxazolidinium, -piperidinium, or -morpholinium cations (alkyl=nC4H9, alkyl ether=CH3OCH2, CH3OCH2CH2) and a perfluoroalkyltrifluoroborate anion ([RFBF3],, RF=CF3, C2F5, nC3F7, nC4F9), were synthesized and characterized. Most of these salts are liquids at room temperature. The key properties of these salts,phase transitions, thermal stability, density, viscosity, conductivity, and electrochemical windows,were measured and compared to those of their corresponding [BF4], and [(CF3SO2)2N], salts. The structural effect on all the above properties was intensively studied in terms of the identity of the cation and anion, variation of the side chain in the cation (i.e., alkyl versus alkyl ether), and change in the length of the perfluoroalkyl group (RF) in the [RFBF3], ion. The reduction of Li+ ions and reoxidation of Li metal took place in pure N -butyl- N -methylpyrrolidinium pentafluoroethyltrifluoroborate as the supporting electrolyte. Such comprehensive studies enhance the knowledge necessary to design and optimize ionic liquids for many applications, including electrolytes. Some of these new salts show desirable properties, including low melting points, high thermal stabilities, low viscosities, high conductivities, and wide electrochemical windows, and may thus be potential candidates for use as electrolytes in high-energy storage devices. In addition, many salts are ionic plastic crystals. [source] Multiwalled Carbon Nanotubes Covalently Modified with Fast Black K,CHEMPHYSCHEM, Issue 4 2005Henry C. Leventis Nanoscale electrochemical switching device: A novel material comprising molecules of the azo-dye Fast Black K (2,5-dimethoxy-4-[(4-nitrophenyl)azo]benzenediazonium chloride, FBK) covalently attached to multiwalled carbon nanotubes (MWCNTs) is shown to form the basis of a nanoscale voltammetric switching device (see picture) for use in electronic nanocircuits, or alternatively, in high-density memory storage devices. The FBK-derivatised MWCNTs may also be used as a chemical release reagent. [source] Nanostructured Carbon and Carbon Nanocomposites for Electrochemical Energy Storage ApplicationsCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 2 2010Sheng Su Abstract Electrochemical energy storage is one of the important technologies for a sustainable future of our society, in times of energy crisis. Lithium-ion batteries and supercapacitors with their high energy or power densities, portability, and promising cycling life are the cores of future technologies. This Review describes some materials science aspects on nanocarbon-based materials for these applications. Nanostructuring (decreasing dimensions) and nanoarchitecturing (combining or assembling several nanometer-scale building blocks) are landmarks in the development of high-performance electrodes for with long cycle lifes and high safety. Numerous works reviewed herein have shown higher performances for such electrodes, but mostly give diverse values that show no converging tendency towards future development. The lack of knowledge about interface processes and defect dynamics of electrodes, as well as the missing cooperation between material scientists, electrochemists, and battery engineers, are reasons for the currently widespread trial-and-error strategy of experiments. A concerted action between all of these disciplines is a prerequisite for the future development of electrochemical energy storage devices. [source] | |||||||||||||||||||