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Generation System (generation + system)

Distribution by Scientific Domains
Engineering57%
Chemistry17%
Polymers and Materials Science7%
Information Science and Computing7%

Kinds of Generation System

  • power generation system
    		•

    Selected Abstracts

    Choosing Rhetorical Structures To Plan Instructional Texts

    COMPUTATIONAL INTELLIGENCE, Issue 3 2000
    Leila Kosseim
    This paper discusses a fundamental problem in natural language generation: how to organize the content of a text in a coherent and natural way. In this research, we set out to determine the semantic content and the rhetorical structure of texts and to develop heuristics to perform this process automatically within a text generation framework. The study was performed on a specific language and textual genre: French instructional texts. From a corpus analysis of these texts, we determined nine senses typically communicated in instructional texts and seven rhetorical relations used to present these senses. From this analysis, we then developed a set of presentation heuristics that determine how the senses to be communicated should be organized rhetorically in order to create a coherent and natural text. The heuristics are based on five types of constraints: conceptual, semantic, rhetorical, pragmatic, and intentional constraints. To verify the heuristics, we developed the spin natural language generation system, which performs all steps of text generation but focuses on the determination of the content and the rhetorical structure of the text. [source]

    Basic study of pole change generator for micro windmill generation system

    ELECTRICAL ENGINEERING IN JAPAN, Issue 1 2010
    Kazuto Yukita
    Abstract This paper proposes a pole change generator for a windmill. Since micro windmill systems generate power from natural energy, power generation characteristics across a wide band are necessary. However, the conventional generator, in which the open voltage is simply proportional to the rotational velocity, encounters difficulty in generating power across a wide range of rotational velocities from low to high, because of the power generation characteristics. To develop a generator with a wide power band suitable for a micro windmill, this paper proposes a technique for switching the status of the generator coil connection. To demonstrate the effectiveness of pole changing, we use a pole-changing generator with 16 coils as an example. The coils can be connected using four patterns: 16-pole series, 8-pole 2-parallel, 4-pole 4-parallel, and 2-pole 8-parallel. Theoretical and experimental studies from this point of view demonstrate that this technique is effective. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(1): 28,36, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20873 [source]

    Experimental study of a doubly-fed rotary frequency converter

    ELECTRICAL ENGINEERING IN JAPAN, Issue 4 2010
    Yasutoshi Takemoto
    Abstract Wind power generation using an unlimited, natural energy has been getting attention regarding environmental issues in recent years, and the installed capacity of wind power generation system is increasing at a rapid pace, resulting in deterioration of power quality especially in frequency and voltage. This fact will be a big problem in restricting large capacity of wind farms. This paper proposes a new frequency converter: rotary frequency converter (RFC) to moderate the electric output from wind generation, which is to be installed between a set of wind generators and a grid, providing a smoothed electric output, promoting the wind power generation introduction. This mainly consists of a synchronous machine and the adjustable-speed machine. Independent controls of input/output voltage, active power, and reactive power offer electrical separation between the two networks. Experimental study of a prototype model and its characteristics, especially dynamic control, is discussed in this paper. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 26,34, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20922 [source]

    Active coordinated operation of a distribution network system for many connections of distributed generators

    ELECTRICAL ENGINEERING IN JAPAN, Issue 3 2009
    Yasuhiro Hayashi
    Abstract Recently, the total number of distributed generators (DGs) such as photovoltaic generation system and wind turbine generation system connected to an actual distribution network has increased drastically. The distribution network connected to many distributed generators must be operated keeping reliability of power supply, power quality, and loss minimization. In order to accomplish active distribution network operation to take advantage of many connections of DGs, a new coordinated operation of distribution system with many connections of DGs is necessary. In this paper, the authors propose a coordinated operation of distribution network system connected to many DGs by using newly proposed sectionalizing switch control, sending voltage control, and computation of available DG connection capability. In order to check the validity of the proposed coordinated operation of distribution system, numerical simulations using the proposed coordinated distribution system operation are carried out in a practical distribution network model. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(3): 46,57, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20655 [source]

    Salt-water recycling for brine production at road-salt-storage facilities

    ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 4 2009
    G. Michael Fitch
    Abstract This research investigates the storm-water quality at road-salt-storage facilities located at Virginia Department of Transportation (VDOT) winter maintenance locations and investigates the feasibility of a sustainable solution to better manage the salt-contaminated storm-water runoff. Collection ponds are currently used at most salt-storage sites to contain highly saline runoff and prevent its release into the environment. During a synoptic, winter-time sampling, chloride-ion concentrations in these ponds were found to be significantly greater than state and federal regulatory guidelines for surface-water-quality criteria, with individual values exceeding 2000 mg/L. The pond water is currently treated as a waste product by VDOT, resulting in significant costs for disposal. However, this saline pond water can potentially be recycled to produce concentrated brine solutions, which can then be used by VDOT for either prewetting dry salt during application to roadways or for direct brine application. Laboratory and field tests have been performed using a bench-scale brine generation system to quantify the effects of hydraulic retention time, temperature, and influent-water quality on system performance. Results of these studies have found that the storm-water runoff captured in collection ponds requires no pretreatment before entering the brine generation system and can effectively produce brine at the target salt concentration. Results of a cost-benefit analysis indicate that it is possible under multiple scenarios to recover the investment capital of implementing brine generation at all VDOT winter maintenance locations, typically within a 4-year horizon. © 2009 American Institute of Chemical Engineers Environ Prog, 2009 [source]

    2D nearly orthogonal mesh generation

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 7 2004
    Yaoxin Zhang
    Abstract The Ryskin and Leal (RL) system is the most widely used mesh generation system for the orthogonal mapping. However, when this system is used in domains with complex geometry, particularly in those with sharp corners and strong curvatures, serious distortion or overlapping of mesh lines may occur and an acceptable solution may not be possible. In the present study, two methods are proposed to generate nearly orthogonal meshes with the smoothness control. In the first method, the original RL system is modified by introducing smoothness control functions, which are formulated through the blending of the conformal mapping and the orthogonal mapping; while in the second method, the RL system is modified by introducing the contribution factors. A hybrid system of both methods is also developed. The proposed methods are illustrated by several test examples. Applications of these methods in a natural river channel are demonstrated. It is shown that the modified RL systems are capable of producing meshes with an adequate balance between the orthogonality and the smoothness for complex computational domains without mesh distortions and overlapping. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Effect of supplementary firing options on cycle performance and CO2 emissions of an IGCC power generation system

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2009
    N. V. Gnanapragasam
    Abstract Supplementary firing is adopted in combined-cycle power plants to reheat low-temperature gas turbine exhaust before entering into the heat recovery steam generator. In an effort to identify suitable supplementary firing options in an integrated gasification combined-cycle (IGCC) power plant configuration, so as to use coal effectively, the performance is compared for three different supplementary firing options. The comparison identifies the better of the supplementary firing options based on higher efficiency and work output per unit mass of coal and lower CO2 emissions. The three supplementary firing options with the corresponding fuel used for the supplementary firing are: (i) partial gasification with char, (ii) full gasification with coal and (iii) full gasification with syngas. The performance of the IGCC system with these three options is compared with an option of the IGCC system without supplementary firing. Each supplementary firing option also involves pre-heating of the air entering the gas turbine combustion chamber in the gas cycle and reheating of the low-pressure steam in the steam cycle. The effects on coal consumption and CO2 emissions are analysed by varying the operating conditions such as pressure ratio, gas turbine inlet temperature, air pre-heat and supplementary firing temperature. The results indicate that more work output is produced per unit mass of coal when there is no supplementary firing. Among the supplementary firing options, the full gasification with syngas option produces the highest work output per unit mass of coal, and the partial gasification with char option emits the lowest amount of CO2 per unit mass of coal. Based on the analysis, the most advantageous option for low specific coal consumption and CO2 emissions is the supplementary firing case having full gasification with syngas as the fuel. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Exergoeconomic optimization of a 1000,MW light water reactor power generation system

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2009
    Hoseyn Sayyaadi
    Abstract A typical 1000,MW pressurized water reactor nuclear power plant is considered for optimization. The thermodynamic modeling is performed based on the energy and exergy analysis, while an economic model is developed according to the total revenue requirement method. The objective function based on the exergoeconomic analysis is obtained. The exergoeconomic optimization process with 10 decision variables is performed using a hybrid stochastic/deterministic search algorithm namely as genetic algorithm. The results that are obtained using optimization process are compared with the base case system and the discussion is presented. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    A new type of EFHAT power generation system with effective utilization of latent heat

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2005
    Hongguang Jin
    Abstract On the basis of synergetic integration of an externally fired humid air turbine (EFHAT) cycle and effective recovery of latent heat from the exhaust gas of gas turbine, we have proposed a new type of EFHAT power generation system with effective utilization of latent heat, different from traditional EFHAT system. Due to use of clean humid air as working substance, latent heat can be recovered and utilized to generate hot water for the humidifier. This will enhance the humidification ability, giving rise to performance improvement of the system. As a result, at the turbine inlet temperature of 1123 K, the thermal efficiency of this new system may be expected to be as high as 47,48%. Additionally, we obtained the analytical expressions of system performance, and disclosed the relative relationship of system efficiency between the new EFHAT system and the pure externally fired power system. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    A new concept for an osmotic energy converter

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 15 2001
    A. Seppälä
    Abstract A new concept for an osmosis power generation system is presented. While the power production of a conventional system is based on continuous, increasing volumetric flow of solution directed to a turbine, the new concept is based on the pressurizing of fluids by osmosis. Two different new concepts were studied. In the first case, the osmotic module consists of the osmotic membranes, fresh water and solution. In the second case, gas is included in the solution part of the module. Consequently, the new system without gas was found to result in more than 2.5 times higher power values than the conventional concept. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    A geometric approach for the design of MIMO sliding controllers.

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2009
    Application to a wind-driven doubly fed induction generator
    Abstract This paper presents a systematic methodology to design controllers for a general class of nonlinear MIMO systems affine in the control in the presence of bounded uncertainties and disturbances. The design method is developed using a theoretical framework based on the combination of a geometric approach and sliding mode techniques. The resulting robust control law guarantees finite time convergence, whereas chattering reduction is achieved by utilizing the minimum discontinuous action required to ensure disturbance rejection. The proposed methodology is applied to the control of a grid-connected wind energy generation system based on a doubly fed induction generator. The control objectives considered in this paper are maximization of the wind energy conversion and reactive power regulation to minimize machine losses. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Designing man-portable power generation systems for varying power demand

    AICHE JOURNAL, Issue 5 2008
    Mehmet Yunt
    Abstract Portable electronic devices operate at varying power demand levels. This variability of power demand must be considered explicitly in the design of man-portable power generation systems for acceptable performance and portability. In this regard, a mathematical programming based design method is proposed. The method transcribes optimal operation of the system at a given power demand into a mathematical program. The power demand specific programs are incorporated into another upper level mathematical program encoding design requirements to form a final two-stage formulation. The design and operational parameters of the power generation system comprise a solution of the formulation. Unlike designs, based on a nominal power demand, the design guarantees that each power demand and all operational requirements can be satisfied. A detailed study of a microfabricated fuel-cell based system is performed. The proposed method produces smaller designs with significantly better performances than nominal power demand based approaches. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source]

    Temperature controlled burn generation system based on a CO2 laser and a silver halide fiber optic radiometer

    LASERS IN SURGERY AND MEDICINE, Issue 5 2003
    Meir Cohen MD
    Abstract Background and Objectives Experimental animal study of burns is dependent on a reliable burn generation system. Most of the experimental systems used today are unable to produce precise partial thickness burns. This limits the ability to study minor changes associated with burn care. The aim of the study was to develop a method for generating burns with a fixed depth using a CO2 laser burn generation system. Materials and Methods The burn generation system was composed of two components: a burn generation device and a temperature sensing and control system. These components were designed to operate together in order to keep a constant, predetermined skin surface temperature during prolonged burn generation. One hundred thirty-eight spot burns were generated on the back of five shaved 450 g male Wistar rats. The rat skin was exposed to a 70°C for 5,60 seconds. The burned areas were excised and underwent evaluation by hematoxylin-eosin-stained slide microscopy. Results A linear correlation was found between the duration of exposure and the average burn depth (r,=,0.93). This correlation is represented by the equation: burn depth in millimeters,=,0.012×,(duration in seconds of skin exposure at 70°C). Conclusions The fiber-optic-controlled laser burn generation system studied is a reliable tool for creating partial thickness as well as full thickness skin burns in rats. Lasers Surg. Med. 32:413,416, 2003. © 2003 Wiley-Liss, Inc. [source]

    High Frequency AC Power System

    NAVAL ENGINEERS JOURNAL, Issue 4 2008
    RAYMOND M. CALFO
    The Navy's Next Generation Integrated Power System (NGIPS) master plan calls for the evolution of the IPS system from its current medium voltage, 60 Hz state to a high-frequency, medium-voltage AC (HFAC) system in the next 10 years. Beyond that, and pending development of key protection components, a medium-voltage DC system will be considered for implementation. The master plan calls for power generation modules at three power levels across these systems: ,A low power level (2,5 MW) driven by a fuel-efficient diesel prime mover, ,A medium power level (10,15 MW) driven by a gas turbine, and ,A main propulsion power level (20,40 MW) driven by a gas turbine. EMD is currently developing a high-speed, high-frequency, liquid-cooled generator under contract with NAVSEA that will effectively demonstrate the mid-level generator for the HFAC system. It will be coupled directly to the output of a GE LM1600 Gas Turbine to provide a TG set with power density four times more favorable than conventional ATG sets. The generator development is proceeding favorably, with testing at the Navy's land-based test site (LBTS) expected to begin in July 2008. The technology embodied in the high-speed generator can be easily extrapolated to main turbine generator power levels. Given the availability of prime movers at appropriate speeds, the power generation modules for the HFAC system, at all three power levels, could be provided in a much shorter time frame than noted in the NGIPS master plan. This paper will explore the combinations of prime movers and advanced generators that would suit the three power generation modules of the HFAC system. A description of the prime mover and the generator used for each module will be provided to demonstrate the modest level of development needed. The performance parameters for each generation module will be provided, along with key characteristics and dimensions for the set. In the end, the paper will make the case that demonstration of a HFAC power generation system can be made in the short term, allowing the shipbuilding community to take advantage of the benefits of state-of-the-art power dense electrical generation. [source]

    Inhibitory effect of bionic fungicide 2-allylphenol on Botrytis cinerea (Pers. ex Fr.) in vitro,

    PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 12 2009
    Shuangjun Gong
    Abstract BACKGROUND: 2-Allylphenol is a registered fungicide in China to control fungal diseases on tomato, strawberry and apple. It is synthetic and structurally resembles the active ingredient ginkgol isolated from Ginkgo biloba L. bark. 2-Allylphenol has been used in China for 10 years. However, its biochemical mode of action remains unclear. An in vitro study was conducted on the biochemical mechanism of 2-allyphenol inhibiting Botrytis cinerea (Pers. ex Fr.). RESULTS: The inhibition was approximately 3 times stronger when the fungus was grown on non-fermentable source, glycerol, than that on a fermentable carbon source, glucose. Inhibition of B. cinerea and Magnaporthe oryzae (Hebert) Barr mycelial growth was markedly potentiated in the presence of salicylhydroxamic acid (SHAM), an inhibitor of mitochondrial alternative oxidase. Furthermore, at 3 h after treatment with 2-allylphenol, oxygen consumption had recovered, but respiration was resistant to potassium cyanide and sensitive to SHAM, indicating that 2-allylphenol had the ability to induce cyanide-resistant respiration. The mycelium inhibited in the presence of 2-allylphenol grew vigorously after being transferred to a fungicide-free medium, indicating that 2-allylphenol is a fungistatic compound. Adenine nucleotide assay showed that 2-allylphenol depleted ATP content and decreased the energy charge values, which confirmed that 2-allylphenol is involved in the impairment of the ATP energy generation system. CONCLUSION: These results suggested that 2-allylphenol induces cyanide-resistant respiration and causes ATP decrease, and inhibits respiration by an unidentified mechanism. Copyright © 2009 Society of Chemical Industry [source]

    The long term evolution towards a new 3GPP* air interface standard

    BELL LABS TECHNICAL JOURNAL, Issue 4 2007
    Rainer Bachl
    The performance targets for the long term evolution (LTE) of the Universal Mobile Telecommunication System (UMTS) into a 4th generation system have been chosen to be very ambitious. While all of these targets may not be achievable in practice, they have served to motivate the decisions for a particular LTE design. Specifically, we discuss the choice of the multiple access scheme for LTE, provide details on the uplink and downlink transmission formats, analyze the benefits of multiple input multiple output (MIMO), and outline approaches for intercell interference mitigation. The trade-off between usage of MIMO spatial multiplexing and beamforming is shown for a practical system. The required signaling overhead is weighed against the performance improvements available from the additional information. Finally, some examples for the achievable physical layer performance are given. © 2007 Alcatel-Lucent. [source]

    Effects of W-CDMA 1950,MHz EMF emitted by mobile phones on regional cerebral blood flow in humans

    BIOELECTROMAGNETICS, Issue 7 2009
    Yoko Mizuno
    Abstract Use of the third generation mobile phone system is increasing worldwide. This is the first study to investigate the effects of the third generation system on regional cerebral blood flow (rCBF) in humans. We compared effects of the electromagnetic field (EMF) emitted from the Wideband Code Division Multiple Access (W-CDMA) cellular system versus sham control exposure on rCBF in humans. Nine healthy male volunteers participated in this study. Positron emission tomography (PET) scans were obtained before, during, and after unilateral 30,min EMF exposure. The subtraction analysis revealed no significant rCBF changes caused by the EMF conditions compared with the sham exposure, suggesting that EMF emitted by a third generation mobile phone does not affect rCBF in humans. Bioelectromagnetics 30:536,544, 2009. © 2009 Wiley-Liss, Inc. [source]

    Biosynthesis of New Indigoid Inhibitors of Protein Kinases Using Recombinant Cytochrome P450 2A6

    CHEMISTRY & BIODIVERSITY, Issue 1 2005
    Zhongliu-Liu Wu
    Glycogen synthase kinase-3 (GSK-3) is a potential drug target for a number of human diseases. Some indigoids have been found to be potent inhibitors of GSK-3, and individual compounds with better activity, specificity, and solubility are desired. In this work, a new disubstituted indigoid generation system was developed with a tryptophanase-deficient Escherichia coli strain as a host to express the human cytochrome P450 2A6 mutant L240C/N297Q, which catalyzes the oxidation of indole to isatin and indoxyl, which in turn react to generate indigoids. Forty-five substituted 1H -indoles from commercial sources were used as substrates in the system, and indigoid mixtures were tested as potential inhibitors of GSK-3. After preliminary screening, cell extracts with high inhibitory activity towards GSK-3,/, were fractionated, and the IC50 values of twelve individual indigoids were measured for GSK-3,/, as well as the protein kinases CDK1/cyclinB and CDK5/p25. Several indigoids, including an indigo, showed stronger inhibition than found in previous work. The most potent towards GSK-3,/,, dimethyl indirubin 5,5,-dicarboxylate (IC50 of 51,nM), was modified by chemical reactions. One product, indirubin 5,5,-dicarboxylic acid 5-methyl ester, inhibited GSK-3,/, with an IC50 of 14,nM and selectivity nearly 40-fold over CDK1 and CDK5. Indirubin-5-5,-dicarbonitrile was also modified to the corresponding 3,-oxime, which had low specificity but showed very high inhibition of all three kinases with IC50 values of 5, 13, and 10,nM towards GSK-3,/,, CDK1, and CDK5, respectively. Thus, this system has the potential to generate new indigoids with therapeutic potential. [source]

    Computation of locational and hourly maximum output of a distributed generator connected to a distribution feeder

    ELECTRICAL ENGINEERING IN JAPAN, Issue 2 2009
    Yasuhiro Hayashi
    Abstract Recently, the total number of distributed generation such as photovoltaic generation systems and wind turbine generation systems connected to a distribution network has drastically increased. Distributed generation using renewable energy can reduce the distribution loss and emission of CO2. However, the distribution network with the distributed generators must be operated while maintaining the reliability of the power supply and power quality. In this paper, the authors propose a computational method to determine the maximum output of a distributed generator under operational constraints [(1) voltage limit, (2) line current capacity, and (3) no reverse flow to bank] at arbitrary connection points and hourly periods. In the proposed method, a three-phase iterative load flow calculation is applied to evaluate the above operational constraints. The three-phase iterative load flow calculation has two simple procedures: (Procedure 1) addition of load currents from the terminal node of the feeder to root one, and (Procedure 2) subtraction of voltage drop from the root node of the feeder to terminal one. In order to check the validity of the proposed method, numerical simulations are performed for a distribution system model. Furthermore, the characteristics of locational and hourly maximum output of a distributed generator connected to a distribution feeder are analyzed using several numerical examples. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 38,47, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20610 [source]

    Autonomous power system for island or grid-connected wind turbines in distributed generation

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 7 2008
    Grzegorz Iwanski
    Abstract Modern power generation systems for wind turbines are often based on the rotor fed slip-ring machines. Power electronics converter provides the slip power, and also the reactive power for excitation of the generator during standalone operation. This way the isolated load can be supplied even if the grid has failed. Stator voltage in an autonomous operation is controlled using vectorial phase locked loop (PLL) structure; therefore the information about mechanical speed or angular position of the rotor is eliminated from the control method. The second PLL is also used for synchronization of the generated voltage with the grid voltage. Voltages synchronization is necessary for soft connection and protection of the supplied load from the rapid change of the supply voltage phase. The grid-connected doubly fed induction generator (DFIG) can be useful after grid fault; however, the mains outage detection methods are necessary for fast disconnection after grid failures. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    A comprehensive techno-economic analysis method for power generation systems with CO2 capture

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2010
    Gang Xu
    Abstract A new comprehensive techno-economic analysis method for power generation systems with CO2 capture is proposed in this paper. The correlative relationship between the efficiency penalty, investment increment, and CO2 avoidance cost is established. Through theoretical derivation, typical system analysis, and variation trends investigation, the mutual influence between technical and economic factors and their impacts on the CO2 avoidance cost are studied. At the same time, the important role that system integration plays in CO2 avoidance is investigated based on the analysis of a novel partial gasification CO2 recovery system. The results reveal that for the power generation systems with CO2 capture, the efficiency penalty not only affects the costs on fuel, but the incremental investment cost for CO2 capture (U.S.$,kW,1) as well. Consequently, it will have a decisive impact on the CO2 avoidance cost. Therefore, the added attention should be paid to improve the technical performance in order to reduce the efficiency penalty in energy system with CO2 capture and storage. Additionally, the system integration may not only decrease the efficiency penalty, but also simplify the system structure and keep the investment increment at a low level, and thereby it reduces the CO2 avoidance cost significantly. For example, for the novel partial gasification CO2 recovery system, owing to system integration, its efficiency can reach 42.2%, with 70% of CO2 capture, and its investment cost is only 87$,kW,1 higher than that of the reference IGCC system, thereby the CO2 avoidance cost is only 6.23$,t,1 CO2. The obtained results provide a comprehensive technical,economical analysis method for energy systems with CO2 capture useful for reducing the avoidance costs. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Designing man-portable power generation systems for varying power demand

    AICHE JOURNAL, Issue 5 2008
    Mehmet Yunt
    Abstract Portable electronic devices operate at varying power demand levels. This variability of power demand must be considered explicitly in the design of man-portable power generation systems for acceptable performance and portability. In this regard, a mathematical programming based design method is proposed. The method transcribes optimal operation of the system at a given power demand into a mathematical program. The power demand specific programs are incorporated into another upper level mathematical program encoding design requirements to form a final two-stage formulation. The design and operational parameters of the power generation system comprise a solution of the formulation. Unlike designs, based on a nominal power demand, the design guarantees that each power demand and all operational requirements can be satisfied. A detailed study of a microfabricated fuel-cell based system is performed. The proposed method produces smaller designs with significantly better performances than nominal power demand based approaches. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source]

    Developments in Oxide Fiber Composites

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2006
    Frank W. Zok
    Prospects for revolutionary design of future power generation systems are contingent on the development of durable high-performance ceramic composites. With recent discoveries in materials and manufacturing concepts, composites with all-oxide constituents have emerged as leading candidates, especially for components requiring a long service life in oxidizing environments. Their insertion into engineering systems is imminent. The intent of this article is to present a synopsis of the current understanding of oxide composites as well as to identify outstanding issues that require resolution for successful implementation. Emphasis is directed toward material systems and microstructural concepts that lead to high toughness and long-term durability. These include: the emergence of La monazite and related compounds as fiber-coating materials, the introduction of the porous-matrix concept as an alternative to fiber coatings, and novel strategies for enabling damage tolerance while retaining long-term morphological stability. Additionally, materials and mechanics models that provide insights into material design, morphology evolution, and composite properties are reviewed. [source]

    Effect of Fullerene on Photocurrent Performance of 6- O -Porphyrin-2,3-di- O -stearoylcellulose Langmuir-Blodgett Films

    MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 12 2008
    Keita Sakakibara
    Abstract Thin films consisting of 6- O -porphyrin-2,3-di- O -stearoylcellulose (H2PCS) and fullerene (C60) were fabricated for anodic photocurrent generation systems by the Langmuir-Blodgett (LB) technique. The , -complexation between the porphyrin moiety and C60 in the LB films was investigated by means of the surface pressure (,)-area (A) isotherms, UV-vis, and fluorescence spectroscopy. The photocurrent density generated from the H2PCS,C60 LB monolayer films exhibited an increase with increasing the C60 proportion and reached a maximum at a mixing ratio of 1:2, yielding a quantum yield of 12.5% and an IPCE (incident photon-to-current efficiency) of 0.50% at a bias potential of +100 mV vs. SCE. Furthermore, the LB five-layer films could give rise to the IPCE value of 1.5% at +100 mV without significant decline of the quantum yields, which was due to the function of C60 as an electron carrier to improve the interlayer electron transfer through each layer. These results have demonstrated a promising method for preparing the donor,acceptor systems using cellulose as a scaffold in the LB films. [source]