Thrust generation by a heaving flexible foil: Resonance, nonlinearities, and optimality

Science.gov (United States)

Paraz, Florine; Schouveiler, Lionel; Eloy, Christophe

2016-01-01

Flexibility of marine animal fins has been thought to enhance swimming performance. However, despite numerous experimental and numerical studies on flapping flexible foils, there is still no clear understanding of the effect of flexibility and flapping amplitude on thrust generation and swimming efficiency. Here, to address this question, we combine experiments on a model system and a weakly nonlinear analysis. Experiments consist in immersing a flexible rectangular plate in a uniform flow and forcing this plate into a heaving motion at its leading edge. A complementary theoretical model is developed assuming a two-dimensional inviscid problem. In this model, nonlinear effects are taken into account by considering a transverse resistive drag. Under these hypotheses, a modal decomposition of the system motion allows us to predict the plate response amplitude and the generated thrust, as a function of the forcing amplitude and frequency. We show that this model can correctly predict the experimental data on plate kinematic response and thrust generation, as well as other data found in the literature. We also discuss the question of efficiency in the context of bio-inspired propulsion. Using the proposed model, we show that the optimal propeller for a given thrust and a given swimming speed is achieved when the actuating frequency is tuned to a resonance of the system, and when the optimal forcing amplitude scales as the square root of the required thrust.

Flexible ceramic gasket for SOFC generator

Science.gov (United States)

Zafred, Paolo [Murrysville, PA; Prevish, Thomas [Trafford, PA

2009-02-03

A solid oxide fuel cell generator (10) contains stacks of hollow axially elongated fuel cells (36) having an open top end (37), an oxidant inlet plenum (52), a feed fuel plenum (11), a combustion chamber (94) for combusting reacted oxidant/spent fuel; and, optionally, a fuel recirculation chamber (106) below the combustion chamber (94), where the fuel recirculation chamber (94) is in part defined by semi-porous fuel cell positioning gasket (108), all within an outer generator enclosure (8), wherein the fuel cell gasket (108) has a laminate structure comprising at least a compliant fibrous mat support layer and a strong, yet flexible woven layer, which may contain catalytic particles facing the combustion chamber, where the catalyst, if used, is effective to further oxidize exhaust fuel and protect the open top end (37) of the fuel cells.

Refrigeration generation using expander-generator units

Science.gov (United States)

Klimenko, A. V.; Agababov, V. S.; Koryagin, A. V.; Baidakova, Yu. O.

2016-05-01

The problems of using the expander-generator unit (EGU) to generate refrigeration, along with electricity were considered. It is shown that, on the level of the temperatures of refrigeration flows using the EGU, one can provide the refrigeration supply of the different consumers: ventilation and air conditioning plants and industrial refrigerators and freezers. The analysis of influence of process parameters on the cooling power of the EGU, which depends on the parameters of the gas expansion process in the expander and temperatures of cooled environment, was carried out. The schematic diagram of refrigeration generation plant based on EGU is presented. The features and advantages of EGU to generate refrigeration compared with thermotransformer of steam compressive and absorption types were shown, namely: there is no need to use the energy generated by burning fuel to operate the EGU; beneficial use of the heat delivered to gas from the flow being cooled in equipment operating on gas; energy production along with refrigeration generation, which makes it possible to create, using EGU, the trigeneration plants without using the energy power equipment. It is shown that the level of the temperatures of refrigeration flows, which can be obtained by using the EGU on existing technological decompression stations of the transported gas, allows providing the refrigeration supply of various consumers. The information that the refrigeration capacity of an expander-generator unit not only depends on the parameters of the process of expansion of gas flowing in the expander (flow rate, temperatures and pressures at the inlet and outlet) but it is also determined by the temperature needed for a consumer and the initial temperature of the flow of the refrigeration-carrier being cooled. The conclusion was made that the expander-generator units can be used to create trigeneration plants both at major power plants and at small energy.

Steam generator replacement in Bruce A Unit 1 and Unit 2

International Nuclear Information System (INIS)

Hart, R.S.

2006-01-01

The Bruce A Generating Station consists of four 900 MW class CANDU units. The reactor and Primary Heat Transport System for each Unit are housed within a reinforced concrete reactor vault. A large duct running below the reactor vaults accommodates the shared fuel handling system, and connects the four reactor vaults to the vacuum building. The reactor vaults, fuelling system duct and the vacuum building constitute the station vacuum containment system. Bruce A Unit 2 was shut down in 1995 and Bruce A Units 1, 3 and 4 were shutdown in 1997. Bruce A Units 3 and 4 were returned to service in late 2003 and are currently operating. Units 1 and 2 remain out of service. Bruce Power is currently undertaking a major rehabilitation of Bruce A Unit 1 and Units 2 that will extend the in-service life of these units by at least 25 years. Replacement of the Steam Generators (eight in each unit) is required; this work was awarded to SNC-Lavalin Nuclear (SLN). The existing steam drums (which house the steam separation and drying equipment) will be retained. Unit 2 is scheduled to be synchronized with the grid in 2009, followed by Unit 1 in 2009. Each Bruce A unit has two steam generating assemblies, one located above and to each end of the reactor. Each steam generating assembly consists of a horizontal cylindrical steam drum and four vertical Steam Generators. The vertical Steam Generators connect to individual nozzles that are located on the underside of the Steam Drum (SD). The steam drums are located in concrete shielding structures (steam drum enclosures). The lower sections of the Steam Generators penetrate the top of the reactor vaults: the containment pressure boundary is established by bellows assemblies that connect between the reactor vault roof slab and the Steam Generators. Each Steam Generators is supported from the bottom by a trapeze that is suspended from the reactor vault top structure. The Steam Generator Replacement (SGR) methodology developed by SLN for Unit 1

Development of high-flexible triboelectric generators using plastic metal as electrodes

Science.gov (United States)

Yang, Sen-Yeu; Shih, Jian-Fu; Chang, Chih-Chieh; Yang, Chii-Rong

2017-02-01

A triboelectric generator is a device that harvests energy through the conversion of mechanical energy into electrical energy. In this work, two polymer materials (PDMS and PET) were selected as triboelectric layers in conjunction with plastic metal (PM) films as conductive layers to produce an electrode with high flexibility. The PDMS film was fabricated with a microstructural array to enhance friction. The proposed PM material was prepared by mixing gallium-indium liquid metal and a glaze powder with excellent coating ability, extensibility, and conductivity. Results demonstrate the superior characteristics of the PM flexible electrodes, including large bending angle (≥180°), small curvature radius (≤1 mm), and stable conductivity. This PM-based triboelectric generator can achieve average output voltage of 80 V and current of 37.2 μA. The proposed flexible electrode with a PM conductive layer could be expected to make a notable contribution to the development of wearable devices.

Human spinal locomotor control is based on flexibly organized burst generators

OpenAIRE

Danner, Simon M.; Hofstoetter, Ursula S.; Freundl, Brigitta; Binder, Heinrich; Mayr, Winfried; Rattay, Frank; Minassian, Karen

2015-01-01

Understanding the organisation of human spinal locomotor circuitry after severe CNS damage is essential for improving neurorehabilitation strategies. Danner et al. present evidence of flexibly organised burst-generating elements within the functionally isolated human lumbosacral spinal cord that generate rhythmic patterns in response to constant, repetitive epidural stimulation.

Steam generator replacement in Bruce A Unit 1 and Unit 2

International Nuclear Information System (INIS)

Hart, R.S.

2007-01-01

The Bruce A Generating Station consists of four 900 MW class CANDU units. The reactor and Primary Heat Transport System for each Unit are housed within a reinforced concrete reactor vault. A large duct running below the reactor vaults accommodates the shared fuel handling system, and connects the four reactor vaults to the vacuum building. The reactor vaults, fuelling system duct and the vacuum building constitute the station vacuum containment system. Bruce A Unit 2 was shut down in 1995 and Bruce A Units 1, 3 and 4 were shutdown in 1997. Bruce A Units 3 and 4 were returned to service in late 2003 and are currently operating. Units 1 and 2 remain out of service. Bruce Power is currently undertaking a major rehabilitation of Bruce A Unit 1 and Unit 2 that will extend the in-service tile of these units by at least 25 years. Replacement of the Steam Generators (eight in each unit) is required; this work was awarded to SNC-Lavalin Nuclear (SLN). The existing steam drums (which house the steam separation and drying equipment) will be retained. Unit 2 is scheduled to be synchronized with the grid in 2009, followed by Unit 1 in 2009. Each Bruce A unit has two steam generating assemblies, one located above and to each end of the reactor. Each steam generating assembly consists of a horizontal cylindrical steam drum and four vertical Steam Generators. The vertical Steam Generators connect to individual nozzles that are located on the underside of the Steam Drum (SD). The steam drums are located in concrete shielding structures (steam drum enclosures). The lower sections of the Steam Generators penetrate the top of the reactor vaults: the containment pressure boundary is established by bellows assemblies that connect between the reactor vault roof slab and the Steam Generators. Each Steam Generators is supported from he bottom by a trapeze that is suspended from the reactor vault top structure. The Steam Generator Replacement (SGR) methodology developed by SLN for Unit 1

The influence of time units on the flexibility of the spatial numerical association of response codes effect.

Science.gov (United States)

Zhao, Tingting; He, Xianyou; Zhao, Xueru; Huang, Jianrui; Zhang, Wei; Wu, Shuang; Chen, Qi

2018-05-01

The Spatial Numerical/Temporal Association of Response Codes (SNARC/STEARC) effects are considered evidence of the association between number or time and space, respectively. As the SNARC effect was proposed by Dehaene, Bossini, and Giraux in 1993, several studies have suggested that different tasks and cultural factors can affect the flexibility of the SNARC effect. This study explored the influence of time units on the flexibility of the SNARC effect via materials with Arabic numbers, which were suffixed with time units and subjected to magnitude comparison tasks. Experiment 1 replicated the SNARC effect for numbers and the STEARC effect for time units. Experiment 2 explored the flexibility of the SNARC effect when numbers were attached to time units, which either conflicted with the numerical magnitude or in which the time units were the same or different. Experiment 3 explored whether the SNARC effect of numbers was stable when numbers were near the transition of two adjacent time units. The results indicate that the SNARC effect was flexible when the numbers were suffixed with time units: Time units influenced the direction of the SNARC effect in a way which could not be accounted for by the mathematical differences between the time units and numbers. This suggests that the SNARC effect is not obligatory and can be easily adapted or inhibited based on the current context. © 2017 The Authors. British Journal of Psychology published by John Wiley & Sons Ltd on behalf of British Psychological Society.

Roll type conducting polymer legs for rigid-flexible thermoelectric generator

Directory of Open Access Journals (Sweden)

Teahoon Park

2017-07-01

Full Text Available A roll-type conducting polymer film was explored as a flexible organic p-type thermoelectric leg using poly(3,4-ethylenedioxythiophene (PEDOT doped with tosylate. The PEDOT films were prepared through solution casting polymerization and rolled up for a roll-type leg. Due to the high flexibility, the roll-type PEDOT leg enabled easy contact to both top and bottom electrodes. Simulation on the dynamic heat transfer and convective cooling for a vertically roosted rod- and roll-type PEDOT leg showed that the temperature difference (ΔT between the hot and cold sides of the leg was much higher in the roll than that of the rod. The PEDOT legs were integrated with n-type Bi2Te3 blocks, to give a 36-couple rigid-flexible thermoelectric generator (RF-TEG. The maximum output voltage from the 36-couple RF-TEG under a ΔT of 7.9 K was determined as 36.7 mV along with a high output power of 115 nW. A wearable RF-TEG was prepared upon the combination of the 36-couple RF-TEG with an arm warmer, to afford an output voltage of 10.6 mV, which was generated constantly and steadily from human wrist heat.

Local Flexibility Market Design for Aggregators Providing Multiple Flexibility Services at Distribution Network Level

Directory of Open Access Journals (Sweden)

Pol Olivella-Rosell

2018-04-01

Full Text Available This paper presents a general description of local flexibility markets as a market-based management mechanism for aggregators. The high penetration of distributed energy resources introduces new flexibility services like prosumer or community self-balancing, congestion management and time-of-use optimization. This work is focused on the flexibility framework to enable multiple participants to compete for selling or buying flexibility. In this framework, the aggregator acts as a local market operator and supervises flexibility transactions of the local energy community. Local market participation is voluntary. Potential flexibility stakeholders are the distribution system operator, the balance responsible party and end-users themselves. Flexibility is sold by means of loads, generators, storage units and electric vehicles. Finally, this paper presents needed interactions between all local market stakeholders, the corresponding inputs and outputs of local market operation algorithms from participants and a case study to highlight the application of the local flexibility market in three scenarios. The local market framework could postpone grid upgrades, reduce energy costs and increase distribution grids’ hosting capacity.

Flexible edge seal for vacuum insulating glazing units

Science.gov (United States)

Bettger, Kenneth J.; Stark, David H.

2012-12-11

A flexible edge seal is provided for a vacuum insulating glazing unit having a first glass pane and a second glass pane spaced-apart from the first. The edge seal comprises a seal member formed of a hermetically bondable material and having a first end, a second end and a center section disposed therebetween. The first end is hermetically bondable to a first glass pane. The second end is hermetically bondable to a second glass pane. The center section comprises a plurality of convolutes.

Characteristics and parametric analysis of a novel flexible ink-based thermoelectric generator for human body sensor

DEFF Research Database (Denmark)

Qing, Shaowei; Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

2018-01-01

Flexible thermoelectric generator became an attractive technology for its wide use especially for curved surfaces applications. This study proposes design of a flexible thermoelectric generator, which is part of a sensor and supplies required electrical power for human body application...... elements thickness and thermoelectric module row number in a proper range can significantly enhance thermoelectric generator performance. The maximum output power can reach 0.2 μW/cm2, which indicates the proposed design is promising for supplying human body sensors. In addition, the basic optimal design....... The thermoelectric generator module has ink-based thermoelements which are made of nano-carbon bismuth telluride materials. Flexible fins conduct the body heat to the thermoelectric uni-couples, extended fins exchange the heat from the cold side of the thermoelectric generator to the ambient. A fully developed one...

Generation unit selection via capital asset pricing model for generation planning

Energy Technology Data Exchange (ETDEWEB)

Romy Cahyadi; K. Jo Min; Chung-Hsiao Wang; Nick Abi-Samra [College of Engineering, Ames, IA (USA)

2003-11-01

The USA's electric power industry is undergoing substantial regulatory and organizational changes. Such changes introduce substantial financial risk in generation planning. In order to incorporate the financial risk into the capital investment decision process of generation planning, this paper develops and analyses a generation unit selection process via the capital asset pricing model (CAPM). In particular, utilizing realistic data on gas-fired, coal-fired, and wind power generation units, the authors show which and how concrete steps can be taken for generation planning purposes. It is hoped that the generation unit selection process will help utilities in the area of effective and efficient generation planning when financial risks are considered. 20 refs., 14 tabs.

Unit commitment and investment valuation of flexible biogas plants in German power markets

Energy Technology Data Exchange (ETDEWEB)

Hochloff, Patrick

2017-07-01

Biogas plants contribute a significant share of renewable energy sources (RES) to the electricity system. Most of them are designed to supply constant power generation. In the future biogas plants will most likely become more flexible, scheduling their power generation with respect to market prices. For this purpose power units need extended electrical capacity to convert the continuously produced gas as well as the gas held in storage. When constructing extended capacity at biogas plants, the flexibility premium is the main focus for about 8000 plants which were constructed before August 2014. Additional incomes as a result of selling at higher market prices have been considered, too. However, their relationship to the electrical capacity and storage size of biogas plants was unknown as was the impact on investment valuation. This work has shown how biogas plants with extended capacity can be analyzed when they are operated in power markets, in particular the power spot market and the control reserve markets. Models on the basis of unit commitment have been developed in order to obtain optimized schedules and financial parameters, such as gross income and net present value (NPV), when biogas plants with extended capacity capitalize on prices in each market. The models developed consider several use cases that describe possible ways of participating in German power markets, switching between static and variable gas supply, providing secondary and tertiary control reserve, and claiming the market and flexibility premium. Mixed integer linear programs (MILP) have been developed for the unit commitment of each use case. The model for the unit commitment of providing control reserve with biogas plants made significant progress compared to the state of the art and has been published in (Hochloff, Braun 2014). There are two ways to make use of this model. First of all, the model could be applied to plan daily schedules for the operation of gas plants located at a gas

Unit commitment and investment valuation of flexible biogas plants in German power markets

International Nuclear Information System (INIS)

Hochloff, Patrick

2017-01-01

Biogas plants contribute a significant share of renewable energy sources (RES) to the electricity system. Most of them are designed to supply constant power generation. In the future biogas plants will most likely become more flexible, scheduling their power generation with respect to market prices. For this purpose power units need extended electrical capacity to convert the continuously produced gas as well as the gas held in storage. When constructing extended capacity at biogas plants, the flexibility premium is the main focus for about 8000 plants which were constructed before August 2014. Additional incomes as a result of selling at higher market prices have been considered, too. However, their relationship to the electrical capacity and storage size of biogas plants was unknown as was the impact on investment valuation. This work has shown how biogas plants with extended capacity can be analyzed when they are operated in power markets, in particular the power spot market and the control reserve markets. Models on the basis of unit commitment have been developed in order to obtain optimized schedules and financial parameters, such as gross income and net present value (NPV), when biogas plants with extended capacity capitalize on prices in each market. The models developed consider several use cases that describe possible ways of participating in German power markets, switching between static and variable gas supply, providing secondary and tertiary control reserve, and claiming the market and flexibility premium. Mixed integer linear programs (MILP) have been developed for the unit commitment of each use case. The model for the unit commitment of providing control reserve with biogas plants made significant progress compared to the state of the art and has been published in (Hochloff, Braun 2014). There are two ways to make use of this model. First of all, the model could be applied to plan daily schedules for the operation of gas plants located at a gas

Coordination and Control of Flexible Building Loads for Renewable Integration; Demonstrations using VOLTTRON

Energy Technology Data Exchange (ETDEWEB)

Hao, He [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liu, Guopeng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Sen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Katipamula, Srinivas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-10-31

Renewable energy resources such as wind and solar power have a high degree of uncertainty. Large-scale integration of these variable generation sources into the grid is a big challenge for power system operators. Buildings, in which we live and work, consume about 75% of the total electricity in the United States. They also have a large capacity of power flexibility due to their massive thermal capacitance. Therefore, they present a great opportunity to help the grid to manage power balance. In this report, we study coordination and control of flexible building loads for renewable integration. We first present the motivation and background, and conduct a literature review on building-to-grid integration. We also compile a catalog of flexible building loads that have great potential for renewable integration, and discuss their characteristics. We next collect solar generation data from a photovoltaic panel on Pacific Northwest National Laboratory campus, and conduct data analysis to study their characteristics. We find that solar generation output has a strong uncertainty, and the uncertainty occurs at almost all time scales. Additional data from other sources are also used to verify our study. We propose two transactive coordination strategies to manage flexible building loads for renewable integration. We prove the theories that support the two transactive coordination strategies and discuss their pros and cons. In this report, we select three types of flexible building loads—air-handling unit, rooftop unit, and a population of WHs—for which we demonstrate control of the flexible load to track a dispatch signal (e.g., renewable generation fluctuation) using experiment, simulation, or hardware-in-the-loop study. More specifically, we present the system description, model identification, controller design, test bed setup, and experiment results for each demonstration. We show that coordination and control of flexible loads has a great potential to integrate

Low carbon technologies as providers of operational flexibility in future power systems

International Nuclear Information System (INIS)

Pavić, Ivan; Capuder, Tomislav; Kuzle, Igor

2016-01-01

Highlights: • Mixed integer linear programming model for provision of multiple services from EV. • EV energy and reserve services provision effects on power system operation. • Impacts of conventional unit’s decommission on system’s operation and flexibility. • Assessment of power system’s flexibility under different wind generation polices. - Abstract: The paper presents a unit commitment model, based on mixed integer linear programming, capable of assessing the impact of electric vehicles (EV) on provision of ancillary services in power systems with high share of renewable energy sources (RES). The analyses show how role of different conventional units changes with integration of variable and uncertain RES and how introducing a flexible sources on the demand side, in this case EV, impact the traditional provision of spinning/contingency reserve services. In addition, technical constraints of conventional units, such as nuclear, gas or coal, limit the inherit flexibility of the system which results in curtailing clean renewable sources and inefficient operation. Following on that, sensitivity analyses of operational cost and wind curtailment shows which techno-economic constraints impact the flexibility of the high RES systems the most and how integration of more flexible units or decommission of conventional nuclear, coal and gas driven power plants would impact the system’s operation. Finally, two different wind generation polices (wind penalization and wind turbines as reserve providers) have been analysed in terms of operational flexibility through different stages of conventional unit’s decommission and compared with the same analyses when EV were used as reserve providers.

All dispenser printed flexible 3D structured thermoelectric generators

Science.gov (United States)

Cao, Z.; Shi, J. J.; Torah, R. N.; Tudor, M. J.; Beeby, S. P.

2015-12-01

This work presents a vertically fabricated 3D thermoelectric generator (TEG) by dispenser printing on flexible polyimide substrate. This direct-write technology only involves printing of electrodes, thermoelectric active materials and structure material, which needs no masks to transfer the patterns onto the substrate. The dimension for single thermoelectric element is 2 mm × 2 mm × 0.5 mm while the distance between adjacent cubes is 1.2 mm. The polymer structure layer was used to support the electrodes which are printed to connect the top ends of the thermoelectric material and ensure the flexibility as well. The advantages and the limitations of the dispenser printed 3D TEGs will also be evaluated in this paper. The proposed method is potential to be a low-cost and scalable fabrication solution for TEGs.

Generation unit selection via capital asset pricing model for generation planning

Energy Technology Data Exchange (ETDEWEB)

Cahyadi, Romy; Jo Min, K. [College of Engineering, Ames, IA (United States); Chunghsiao Wang [LG and E Energy Corp., Louisville, KY (United States); Abi-Samra, Nick [Electric Power Research Inst., Palo Alto, CA (United States)

2003-07-01

The electric power industry in many parts of U.S.A. is undergoing substantial regulatory and organizational changes. Such changes introduce substantial financial risk in generation planning. In order to incorporate the financial risk into the capital investment decision process of generation planning, in this paper, we develop and analyse a generation unit selection process via the capital asset pricing model (CAPM). In particular, utilizing realistic data on gas-fired, coal-fired, and wind power generation units, we show which and how concrete steps can be taken for generation planning purposes. It is hoped that the generation unit selection process developed in this paper will help utilities in the area of effective and efficient generation planning when financial risks are considered. (Author)

Evaluating the benefits of coordinated emerging flexible resources in electricity markets

International Nuclear Information System (INIS)

Heydarian-Forushani, E.; Golshan, M.E.H.; Siano, Pierluigi

2017-01-01

Highlights: •Variable renewable energy sources create a flexibility gap in power system operation. •BESs, PEV PLs and DR are modeled as flexible options. •DR programs have remarkable impacts in terms of cost and emission reduction. •PEV PL is not a favorable flexible option by its own due to uncertain behavior of PEV owners. •Coordinated operation of PEV PLs and BESs under TOU program is the most effective generation mixture. -- Abstract: Increasing share of variable renewable energy sources (VRESs) with the aim of tackling climate changes impose several techno-economic challenges to power system operation. VRESs reduce the available flexibility by displacing existing flexible units due to their priority in dispatch and simultaneously enhance the need for additional flexibility due to their uncertain nature. In this light, the system is faced with a flexibility gap. One way to cover the created flexibility gap is the incorporation of emerging flexible resources into power systems operation. On this basis, this paper proposes a comprehensive flexible generation portfolio including bulk energy storages (BESs), plug-in electric vehicle parking lots (PEV PLs), and demand response (DR) programs. A stochastic market-based model is proposed to coordinate the interactions among these flexibility providers considering different sets of uncertainty, such as wind power generation and PEV owner’s behavior. Finally, various generation mixtures are prioritized based on the system operator’s economic, technical, and environmental desires to provide a guideline to opt the most effective generation mixture in the context of flexibility promotion.

High-efficiency and flexible generation of vector vortex optical fields by a reflective phase-only spatial light modulator.

Science.gov (United States)

Cai, Meng-Qiang; Wang, Zhou-Xiang; Liang, Juan; Wang, Yan-Kun; Gao, Xu-Zhen; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

2017-08-01

The scheme for generating vector optical fields should have not only high efficiency but also flexibility for satisfying the requirements of various applications. However, in general, high efficiency and flexibility are not compatible. Here we present and experimentally demonstrate a solution to directly, flexibly, and efficiently generate vector vortex optical fields (VVOFs) with a reflective phase-only liquid crystal spatial light modulator (LC-SLM) based on optical birefringence of liquid crystal molecules. To generate the VVOFs, this approach needs in principle only a half-wave plate, an LC-SLM, and a quarter-wave plate. This approach has some advantages, including a simple experimental setup, good flexibility, and high efficiency, making the approach very promising in some applications when higher power is need. This approach has a generation efficiency of 44.0%, which is much higher than the 1.1% of the common path interferometric approach.

Generating units performances: power system requirements

Energy Technology Data Exchange (ETDEWEB)

Fourment, C; Girard, N; Lefebvre, H

1994-08-01

The part of generating units within the power system is more than providing power and energy. Their performance are not only measured by their energy efficiency and availability. Namely, there is a strong interaction between the generating units and the power system. The units are essential components of the system: for a given load profile the frequency variation follows directly from the behaviour of the units and their ability to adapt their power output. In the same way, the voltage at the units terminals are the key points to which the voltage profile at each node of the network is linked through the active and especially the reactive power flows. Therefore, the customer will experience the frequency and voltage variations induced by the units behaviour. Moreover, in case of adverse conditions, if the units do not operate as well as expected or trip, a portion of the system, may be the whole system, may collapse. The limitation of the performance of a unit has two kinds of consequences. Firstly, it may result in an increased amount of not supplied energy or loss of load probability: for example if the primary reserve is not sufficient, a generator tripping may lead to an abnormal frequency deviation, and load may have to be shed to restore the balance. Secondly, the limitation of a unit performance results in an economic over-cost for the system: for instance, if not enough `cheap` units are able to load-following, other units with higher operating costs have to be started up. We would like to stress the interest for the operators and design teams of the units on the one hand, and the operators and design teams of the system on the other hand, of dialog and information exchange, in operation but also at the conception stage, in order to find a satisfactory compromise between the system requirements and the consequences for the generating units. (authors). 11 refs., 4 figs.

Cue generation: How learners flexibly support future retrieval.

Science.gov (United States)

Tullis, Jonathan G; Benjamin, Aaron S

2015-08-01

The successful use of memory requires us to be sensitive to the cues that will be present during retrieval. In many situations, we have some control over the external cues that we will encounter. For instance, learners create shopping lists at home to help remember what items to later buy at the grocery store, and they generate computer file names to help remember the contents of those files. Generating cues in the service of later cognitive goals is a complex task that lies at the intersection of metacognition, communication, and memory. In this series of experiments, we investigated how and how well learners generate external mnemonic cues. Across 5 experiments, learners generated a cue for each target word in a to-be-remembered list and received these cues during a later cued recall test. Learners flexibly generated cues in response to different instructional demands and study list compositions. When generating mnemonic cues, as compared to descriptions of target items, learners produced cues that were more distinct than mere descriptions and consequently elicited greater cued recall performance than those descriptions. When learners were aware of competing targets in the study list, they generated mnemonic cues with smaller cue-to-target associative strength but that were even more distinct. These adaptations led to fewer confusions among competing targets and enhanced cued recall performance. These results provide another example of the metacognitively sophisticated tactics that learners use to effectively support future retrieval.

All-solution-processed flexible thin film piezoelectric nanogenerator

Energy Technology Data Exchange (ETDEWEB)

Chung, Sung Yun; Kim, Sunyoung; Kim, Kyongjun [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-744 (Korea, Republic of); Lee, Ju-Hyuck; Kim, Sang-Woo [SKKU Advanced Institute of Nanotechnology, School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Kang, Chong-Yun; Yoon, Seok-Jin [Electronic Materials Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Kim, Youn Sang [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-744 (Korea, Republic of); Advanced Institutes of Convergence Technology, 864-1 Iui-dong, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-270 (Korea, Republic of)

2012-11-27

An all-solution-processed flexible thin film piezoelectric nanogenerator is demonstrated using reactive zinc hydroxo-condensation and a screen-printing method. The highly elastic thin film allows the piezoelectric energy to be generated through the mechanical rolling and muscle stretching of the piezoelectric unit. This flexible all solution-processed nanogenerator is promising for use in future energy harvesters such as wearable human patches and mobile electronics. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Flexible screen printed thick film thermoelectric generator with reduced material resistivity

International Nuclear Information System (INIS)

Cao, Z; Koukharenko, E; Torah, R N; Tudor, J; Beeby, S P

2014-01-01

This work presents a flexible thick-film Bismuth Tellurium/Antimony Tellurium (BiTe/SbTe) thermoelectric generator (TEG) with reduced material resistivity fabricated by screen printing technology. Cold isostatic pressing (CIP) was introduced to lower the resistivity of the printed thermoelectric materials. The Seebeck coefficient (α) and the resistivity (ρ) of printed materials were measured as a function of applied pressure. A prototype TEG with 8 thermocouples was fabricated on flexible polyimide substrate. The dimension of a single printed element was 20 mm × 2 mm × 78.4 pm. The coiled-up prototype produced a voltage of 36.4 mV and a maximum power of 40.3 nW from a temperature gradient of 20 °C

Application of FPGA's in Flexible Analogue Electronic Image Generator Design

Directory of Open Access Journals (Sweden)

Peter Kulla

2006-01-01

Full Text Available This paper focuses on usage of the FPGAs (Field Programmable Gate Arrays Xilinx as a part of our more complex workdedicated to design of flexible analogue electronic images generator for application in TV measurement technique or/and TV servicetechnique or/and education process. The FPGAs performs here the role of component colour R, G, B, synchronization and blanking signals source. These signals are next processed and amplified in other parts of the generator as NTSC/PAL source encoder and RF modulator. The main aim of this paper is to show the possibilities how with suitable development software use a FPGAs in analog TV technology.

BPFlexTemplate: A Business Process template generation tool based on similarity and flexibility

Directory of Open Access Journals (Sweden)

Latifa Ilahi

2017-01-01

Full Text Available In large organizations with multiple organizational units, process variants emerge due to many aspects, including local management policies, resources or socio-technical limitations. Organizations then struggle to improve a business process which has no longer a single process model to redesign, implement and adjust. In this paper, we propose an approach to tackle these two challenges: decrease the proliferation of process variants in these organizations, and foresee, at the same time, the need of having flexible business processes that allow for a certain degree of adjustment. To validate our approach, we first conducted case studies where we collected six real-world business process variants from two organizational units of the same healthcare organization. We then proposed an algorithm to derive a template process model from all the variants, which includes common and flexible process elements. We implemented our approach in a software tool called BPFlexTemplate, and tested it with the elicited variants.

Economical and ecological benchmarking of biogas plant configurations for flexible power generation in future power supply systems

International Nuclear Information System (INIS)

Hahn, Henning

2016-01-01

With the share of intermittent renewable energies within the electricity system rising, balancing services from dispatchable power plants are of increasing importance. This study comparatively assesses the environmental and economic performance of biogas plant configurations, supplying biogas on demand for flexible power generation. A cost analysis of five configurations based on biogas storing and flexible biogas production concepts has been carried out. Results show that additional flexibility costs for a biogas supply of 8 hours per day range between 2 Euro to 11 Euro MWh -1 and for a 72 hour period without biogas demand from 9 Euro to 19 Euro MWh -1 . While biogas storage concepts were identified as favorable short-term supply configurations, flexible biogas production concepts profit from reduced storage requirements at plants with large biogas production capacities or for longer periods without biogas demand [1, 2]. Flexible biogas plant configurations indicate an increased energy demand to operate the operational enhancements compared to conventional biogas plants supplying biogas for baseload power generation. However, findings show that in contrast to an alternative supply of power generators with natural gas, biogas supplied on demand by adapted biogas plant configurations saves greenhouse gas emissions by 54 to 65 g CO 2-eq MJ -1 and primary energy by about 1.17 MJ MJ -1 . In this regard, configurations with flexible biogas production profit from reduced biogas storage requirements and achieve higher savings compared to configurations with continuous biogas production [1, 3].

Nurses' perception of their manager's leadership style and unit climate: are there generational differences?

Science.gov (United States)

Farag, Amany A; Tullai-McGuinness, Susan; Anthony, Mary K

2009-01-01

To describe and compare how nurses representing four age cohorts perceive their manager's leadership style and unit climate. The current workforce consists of nurses representing four generational cohorts. Nursing literature suggests that nurses from each age cohort think, behave and approach work differently. Limited empirical evidence, however, exists about how nurses from each age cohort perceive two aspects of their work environment: their managers' leadership style and unit climate. This cross-sectional, descriptive survey was conducted using a convenience sample of 475 registered nurses working in different inpatient units in three community non-magnet hospitals. Only nurses from Boomer and Gen-Xers had sufficient representation to be included in the data analysis. Nurses from the two main age cohorts did not differ in their perceptions of their manager's leadership style. Significant differences were found in two unit climate dimensions. The Gen-Xers had a less favourable perception of their unit climate related to warmth and belonging and administrative support. Nurse manager's might reflect on how they interact with different age cohorts; and to involve nurses from various age cohorts in the development of policies to create a flexible work environment.

21 CFR 876.4300 - Endoscopic electrosurgical unit and accessories.

Science.gov (United States)

2010-04-01

... Endoscopic electrosurgical unit and accessories. (a) Identification. An endoscopic electrosurgical unit and... device includes the electrosurgical generator, patient plate, electric biopsy forceps, electrode, flexible snare, electrosurgical alarm system, electrosurgical power supply unit, electrical clamp, self...

The disinfection of flexible fibre-optic nasendoscopes out-of-hours: confidential telephone survey of ENT units in England

NARCIS (Netherlands)

Kanagalingam, J.; Zainal, A.; Georgalas, C.; Paun, S.; Tolley, N. S.

2002-01-01

We present the results of a confidential telephone survey of ENT units in England on the disinfection of flexible fibre-optic nasendoscopes out-of-hours. The on-call residents of 124 units were contacted and questioned. In 35.1 per cent of units surveyed, the on-call resident was primarily

A parametric approach for the valuation of power plant flexibility options

Directory of Open Access Journals (Sweden)

Julia Hentschel

2016-11-01

Full Text Available Conventional generation units encounter a changing role in modern societies’ energy supply. With increased need for flexible operation, engineers and project managers have to evaluate the benefits of technical improvements. For this purpose, a valuation tool has been developed, comparing economical cornerstones and technical constraints of generation units to European Energy Exchange prices for PHELIX 2014. It enables the user to relate a change in technical parameters to an economic effect and possible revenues. Four different types of conventional power plants are investigated in scenarios with increasing CO2 and fuel prices to determine the impact of different flexibility options. Results show that an increased ramp rate has not the same magnitude of positive economic impact as reduced minimum operation load, based on an observation on a price signal with resolution of fifteen minutes.

Cost analysis of concepts for a demand oriented biogas supply for flexible power generation.

Science.gov (United States)

Hahn, Henning; Ganagin, Waldemar; Hartmann, Kilian; Wachendorf, Michael

2014-10-01

With the share of intermittent renewable energies within the electricity system rising, balancing services from dispatchable power plants are of increasing importance. Highlighting the importance of the need to keeping fuel costs for flexible power generation to a minimum, the study aims to identify favourable biogas plant configurations, supplying biogas on demand. A cost analysis of five configurations based on biogas storing and flexible biogas production concepts has been carried out. Results show that additional flexibility costs for a biogas supply of 8h per day range between 2€ and 11€MWh(-1) and for a 72h period without biogas demand from 9€ to 19€MWh(-1). While biogas storage concepts were identified as favourable short term supply configurations, flexible biogas production concepts profit from reduced storage requirements at plants with large biogas production capacities or for periods of several hours without biogas demand. Copyright © 2014 Elsevier Ltd. All rights reserved.

New steam generators slated for nuclear units

International Nuclear Information System (INIS)

Anon.

1992-01-01

This article is a brief discussion of Duke Power's plans to replace steam generators at its McGuire and Catawba nuclear units. A letter of intent to purchase (from Babcock and Wilcox) the 12 Westinghouse steam generators has been signed, but no constructor has been selected at this time. This action is brought about by the failures of more than 3000 tubes in these units

Value of Flexible Resources, Virtual Bidding, and Self-Scheduling in Two-Settlement Electricity Markets With Wind Generation – Part I: Principles and Competitive Model

DEFF Research Database (Denmark)

Kazempour, Jalal; Hobbs, Benjamin F.

2017-01-01

Part one of this two-part paper presents new models for evaluating flexible resources in two-settlement electricity markets (day-ahead and real-time) with uncertain net loads (demand minus wind). Physical resources include wind together with fast- and slow-start demand response and thermal...... of certain equivalencies of the four models. We show how virtual bidding enhances market performance, since, together with self-scheduling by slow-start generators, it can help deterministic day-ahead market to choose the most efficient unit commitment....

Increasing the flexibility of operational scheduling for a large-scale CHP plant used for generating district heat and electricity in order to meet the varying market demands; Steigerung der Einsatzflexibilitaet einer grossen KWK-Anlage zur Fernwaerme- und Stromerzeugung gemaess aktueller Marktanforderungen

Energy Technology Data Exchange (ETDEWEB)

Meierer, Matthias; Krupp, Roland; Stork, Rolf [Grosskraftwerk Mannheim AG, Mannheim (Germany)

2015-07-01

The substantial changes in the structure of German power supply plants pose high demands on the flexibility of the operational scheduling of conventional thermal power plants. Grosskraftwerk Mannheim AG is a power plant company that is operating a plant for combined power and district heat generation. The paper describes some measures which have been taken to improve the plant's operational flexibility. In addition, the associated technical systems and their functions, as well as the state of ongoing projects are outlined. Special focus is placed on topics related to issues such as ''district-heat storage unit of the new unit 9, flexibility of operational scheduling, and efficient CHP plant operation''.

Structural Flexibility of Large Direct Drive Generators for Wind Turbines

NARCIS (Netherlands)

Shrestha, G.

2013-01-01

The trend in wind energy is towards large offshore wind farms. This trend has led to the demand for high reliability and large single unit wind turbines. Different energy conversion topologies such as multiple stage geared generators, single stage geared generators and gearless (direct drive)

Indigenous unit for bending and twisting tests of ultra-thin films on a flexible substrate

Science.gov (United States)

D'souza, Slavia Deeksha; Hazarika, Pratim; Prakasarao, Ch Surya; Kovendhan, M.; Kumar, R. Arockia; Joseph, D. Paul

2018-04-01

An indigenous unit is designed to test the stability of thin films deposited on to a flexible substrate by inducing a required number of bending and twisting under specific conditions. The unit is designed using aluminum and automated by sending pulse width modulated signals to servo motors using ATmega328 microcontroller. We have tested the unit by imparting stress on to a commercial ITO film deposited on a PET substrate. After a definite number of bending and twisting cycles, the electrical and surface properties are studied and the results are discussed.

A comparative study of velocity increment generation between the rigid body and flexible models of MMET

Energy Technology Data Exchange (ETDEWEB)

Ismail, Norilmi Amilia, E-mail: aenorilmi@usm.my [School of Aerospace Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

2016-02-01

The motorized momentum exchange tether (MMET) is capable of generating useful velocity increments through spin–orbit coupling. This study presents a comparative study of the velocity increments between the rigid body and flexible models of MMET. The equations of motions of both models in the time domain are transformed into a function of true anomaly. The equations of motion are integrated, and the responses in terms of the velocity increment of the rigid body and flexible models are compared and analysed. Results show that the initial conditions, eccentricity, and flexibility of the tether have significant effects on the velocity increments of the tether.

Flexible and foldable paper-substrate thermoelectric generator (teg)

KAUST Repository

Rojas, Jhonathan Prieto

2017-08-24

Flexible and foldable paper-substrate thermoelectric generators (TEGs) and methods for making the paper-substrate TEGs are disclosed. A method includes depositing a plurality of thermocouples in series on a paper substrate to create a paper-substrate TEG, wherein the plurality of thermocouples is deposited between two contact points of the paper-substrate TEG. The method may also include setting the power density and maximum achievable temperature gradient of the paper-substrate TEG by folding the paper-substrate TEG. A paper-substrate TEG apparatus may include a paper substrate and a plurality of thermocouples deposited in series on the paper substrate between two contact points of the paper-substrate TEG, wherein the power density and maximum achievable temperature gradient of the paper-substrate TEG is set by folding the paper-substrate TEG.

The Economic Merits of Flexible Carbon Capture and Sequestration as a Compliance Strategy with the Clean Power Plan.

Science.gov (United States)

Craig, Michael T; Jaramillo, Paulina; Zhai, Haibo; Klima, Kelly

2017-02-07

Carbon capture and sequestration (CCS) may be a key technology for achieving large CO 2 emission reductions. Relative to "normal" CCS, "flexible" CCS retrofits include solvent storage that allows the generator to temporarily reduce the CCS parasitic load and increase the generator's net efficiency, capacity, and ramp rate. Due to this flexibility, flexible CCS generators provide system benefits that normal CCS generators do not, which could make flexible CCS an economic CO 2 emission reduction strategy. Here, we estimate the system-level cost effectiveness of reducing CO 2 emissions with flexible CCS compared to redispatching (i.e., substituting gas- for coal-fired electricity generation), wind, and normal CCS under the Clean Power Plan (CPP) and a hypothetical more stringent CO 2 emission reduction target ("stronger CPP"). Using a unit commitment and economic dispatch model, we find flexible CCS achieves more cost-effective emission reductions than normal CCS under both reduction targets, indicating that policies that promote CCS should encourage flexible CCS. However, flexible CCS is less cost effective than wind under both reduction targets and less and more cost effective than redispatching under the CPP and stronger CPP, respectively. Thus, CCS will likely be a minor CPP compliance strategy but may play a larger role under a stronger emission reduction target.

Computer finite element analysis of stress derived from particular units of torsionally flexible metal coupling

Directory of Open Access Journals (Sweden)

Mariusz KUCZAJ

2010-01-01

Full Text Available In this article the results of Finite Element Analysis (FEA results of stresses derived from chosen units of torsionally flexible metal coupling are presented. As model and simulation tool for particular component loads is used the Autodesk Inventor Professional 2009 program.

New Generation General Purpose Computer (GPC) compact IBM unit

Science.gov (United States)

1991-01-01

New Generation General Purpose Computer (GPC) compact IBM unit replaces a two-unit earlier generation computer. The new IBM unit is documented in table top views alone (S91-26867, S91-26868), with the onboard equipment it supports including the flight deck CRT screen and keypad (S91-26866), and next to the two earlier versions it replaces (S91-26869).

Scaling law and enhancement of lift generation of an insect-size hovering flexible wing

Science.gov (United States)

Kang, Chang-kwon; Shyy, Wei

2013-01-01

We report a comprehensive scaling law and novel lift generation mechanisms relevant to the aerodynamic functions of structural flexibility in insect flight. Using a Navier–Stokes equation solver, fully coupled to a structural dynamics solver, we consider the hovering motion of a wing of insect size, in which the dynamics of fluid–structure interaction leads to passive wing rotation. Lift generated on the flexible wing scales with the relative shape deformation parameter, whereas the optimal lift is obtained when the wing deformation synchronizes with the imposed translation, consistent with previously reported observations for fruit flies and honeybees. Systematic comparisons with rigid wings illustrate that the nonlinear response in wing motion results in a greater peak angle compared with a simple harmonic motion, yielding higher lift. Moreover, the compliant wing streamlines its shape via camber deformation to mitigate the nonlinear lift-degrading wing–wake interaction to further enhance lift. These bioinspired aeroelastic mechanisms can be used in the development of flapping wing micro-robots. PMID:23760300

Predictive Control of Demand Side Units Participating in the Primary Frequency Reserve Market

DEFF Research Database (Denmark)

Biegel, Benjamin; Stoustrup, Jakob; Andersen, Palle

2013-01-01

We consider an aggregator controlling a mixed portfolio of conventional power generators and demand side units. The generators are controllable within certain power and ramp limitations while the demand side units are characterized by flexible consumptions and therefore can be treated as energy...

FLEXIBLE, HIGH CHAR YIELD HYBRIDSIL ADHESIVE MATERIALS FOR NEXT GENERATION ABLATIVE THERMAL PROTECTION SYSTEMS, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — NanoSonic will create and empirically validate flexible, high char yield HybridSil adhesive nanocomposites for use within current and next generation polymer based...

Vapor generating unit blowdown arrangement

International Nuclear Information System (INIS)

McDonald, B.N.

1978-01-01

A vapor generating unit having a U-shaped tube bundle is provided with an orificed downcomer shroud and a fluid flow distribution plate between the lower hot and cold leg regions to promote fluid entrained sediment deposition in proximity to an apertured blowdown pipe

Quantitative evaluation of flexibility in undergraduate engineering curricula in the United Arab Emirates

Directory of Open Access Journals (Sweden)

Naif A. Darwish

2016-03-01

Full Text Available In academia, smooth progression of students significantly depends on the way curricula are developed and organized. Curricula or study plans with high degree of interconnectivity between courses, multiple prerequisites, and hierarchically structured courses tend to complicate the smooth progress of the enrolled students. In this work, a rigorous quantitative relaxation indicator, developed and published elsewhere by the first author, has been applied to quantify the degree of stiffness and rigidity in undergraduate engineering curricula at the American University of Sharjah (AUS, the University of Sharjah (UOS, United Arab Emirates University (UAEU, and the Petroleum Institute (PI, which are the leading universities in the United Arab Emirates. Results indicate high rigidity (low relaxation indices due to high degree of interconnectivity between courses, specifically in the second year of the study plans. The chemical engineering curriculum at PI exhibited the least flexibility due to very strong pre-and-co-requisite ties while the civil & environmental curriculum at UAEU showed the highest flexibility. The curricula considered require immediate attention and reorganization in order to facilitate smooth sequential progress of the students from one semester to another. A list of courses that require relaxation of strong pre-and corequisites ties has been presented for each curriculum.

Generating unit maintenance scheduling under competitive market environments

International Nuclear Information System (INIS)

Jin Ho Kim; Jong Bae Park; Jong Keun Park; Yeung Han Chun

2005-01-01

A novel approach to a generating unit maintenance scheduling problem in competitive electricity markets is presented in this paper. The objective is to develop a game-theoretic framework for analyzing strategic behaviors of generating companies (Gencos) from the standpoint of the generating unit maintenance scheduling (GMS) game and for obtaining the equilibrium solution for the GMS game. The GMS problem is formulated as a dynamic non-cooperative game with complete information. The players correspond to profit maximizing individual Gencos, and the payoff of each player is defined as the profits from the energy market. The optimal schedule is defined by Nash equilibrium (equilibriums) of the game. Numerical results for two-Genco system are used to demonstrate that the proposed framework can be successfully applied to analyzing the strategic behaviors of each Genco and to obtaining the corresponding Nash equilibrium. The result indicates that generating unit maintenance schedule is one of the major strategic behaviors whereby Genco maximize their profits in a competitive market environment. (author)

Grid Synchronization for Distributed Generations

DEFF Research Database (Denmark)

Peyghami, Saeed; Mokhtari, Hossein; Blaabjerg, Frede

2017-01-01

Distributed generators (DGs) like photovoltaic arrays, wind turbines, and fuel cell modules, as well as distributed storage (DS) units introduce some advantages to the power systems and make it more reliable, flexible, and controllable in comparison with the conventional power systems. Grid inter...

Survey of regulatory agency review of generating unit performance

International Nuclear Information System (INIS)

Roach, E.M. Jr.; Tarletz, D.B.

1985-01-01

Regulatory agencies across the country are being called upon increasingly to monitor the management of electric utilities. Such activity, which once was relatively rare, is now common. Most frequently this oversight centers around the operating performance of generating units, both nuclear and fossil. There are, perhaps, several reasons for this increased interest in the efficient operation of generating units: increased fuel costs and fuel cost differentials, increased lead times and costs for construction of new generating units, and increased dependence on existing units because of construction programs being revised to meet decreased load growth. The monitoring of generating units has taken the form of after the fact evaluation of performance on a case-by-case basis and the implementation of productivity incentive programs. Performance standards are used in these contexts both to measure the adequacy of unit performance and to implement incentives in the form of rewards or penalties. The standard used may be a subjective test of prudent performance or some numerical index of plant performance, e.g., equivalent availability, capacity factor or heat rate. Some of the activity by regulators is reviewed in applying subjective and numerical standards and the considerations involved in applying such standards are discussed

Human spinal locomotor control is based on flexibly organized burst generators.

Science.gov (United States)

Danner, Simon M; Hofstoetter, Ursula S; Freundl, Brigitta; Binder, Heinrich; Mayr, Winfried; Rattay, Frank; Minassian, Karen

2015-03-01

samples of rhythmic patterns. The basic activation patterns can be interpreted as central drives implemented by spinal burst generators that impose specific spatiotemporally organized activation on the lumbosacral motor neuron pools. Our data thus imply that the human lumbar spinal cord circuits can form burst-generating elements that flexibly combine to obtain a wide range of locomotor outputs from a constant, repetitive input. It may be possible to use this flexibility to incorporate specific adaptations to gait and stance to improve locomotor control, even after severe central nervous system damage. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Gamma: A C++ Sound Synthesis Library Further Abstracting the Unit Generator

DEFF Research Database (Denmark)

Putnam, Lance Jonathan

2014-01-01

Gamma is a C++ library for sound synthesis that was created to address some of the limitations of existing sound synthesis libraries. The first limitation is that unit generators cannot easily be organized into separate sampling domains. This makes it difficult to use unit generators with different...... sample rates and in other domains, namely the frequency domain. The second limitation is that certain internal unit generator algorithms, such as interpolation, cannot be customized. This tends to lead to closed architectures consisting of multiple unit generators with only slight algorithmic differences...

Fast discharging homopolar drum-type generator with gas bearing and flexible copper-fiber brushes

International Nuclear Information System (INIS)

Kibardin, A.S.; Komin, A.V.; Sojkin, V.F.; Frolkin, V.I.

1984-01-01

The description and results of testing schock-excited homopolar generator (SEHG) with a drum-type rotor, a gas bearing and flexible copper-fiber brushes are presented. SEHG has a magnetic core with two excitation coils with the designed field of 1.8-2 T in the gap. The drum-type titanium rotor has 80 kg, is 0.5 m in diameter, 0.25 m length and 0.05 m thick. SEHG power is 3.6 MJ, overall dimensions are 0.8x1 m. Single- and double-row bearings, representing an aluminium shell of 15 mm thick, established inside an external backward current lead and isolated from it, are used to control serviceability of a radial gas-static bearing, which is a support for an SEHG rotor. The bearing surface was covered with the colloidal graphite and had one or two rows by 24 openings for swelling. Brush units represent a bronze brush ring, containing 44 copper-fiber brushes. Tests results confirm serviceability of copper-fiber brushes with quite large dimensions and permit to count on producing the 2.4 MA electric discharge and 12 ms pulse rise time

Anticorrosion and halobios control for tidal power generating units

International Nuclear Information System (INIS)

Shen, J C; Ding, L X

2012-01-01

The anticorrosion and halobios control is the key techniquesrelated to the safety and durability of tidal power generating units. The technique of material application, antifouling coating and cathodic protection are often adopted. The technical research, application, updating and development are carried on Jiangxia Tidal Power Station, which is based on the old Unit 1-Unit 5 operated for nearly 30 years, and the new Unit 6 operated in 2007. It is found that stainless steeland the antifouling coating used in Unit 1- Unit 5 are very effective, but cathodic protection is often likely to fail because of the limitation of structure and installation. Analyses and studies for anticorrosion and halobios control techniques of tidal power generating units according to theory, experience and actual effects have been done, which can be for reference to the tidal power station designers and builders.

An infrared-driven flexible pyroelectric generator for non-contact energy harvester

Science.gov (United States)

Zhao, Tingting; Jiang, Weitao; Liu, Hongzhong; Niu, Dong; Li, Xin; Liu, Weihua; Li, Xuan; Chen, Bangdao; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

2016-04-01

In recent years, energy harvesting technologies, which can scavenge many kinds of energies from our living environment to power micro/nanodevices, have attracted increasing attention. However, remote energy transmission, flexibility and electric waveform controllability remain the key challenges for wireless power supply by an energy harvester. In this paper, we design a new infrared-driven non-contact pyroelectric generator for harvesting heat energy, which avoids direct contact between the pyroelectric generator and heat source and realizes remote energy transfer exploiting the photothermal and penetrability of infrared light. The output voltage (under the input impedance of 100 MOhm) and short-circuit current of the pyroelectric generator consisting of a CNT/PVDF/CNT layer (20 mm × 5 mm × 100 μm) can be as large as 1.2 V and 9 nA, respectively, under a 1.45 W cm-2 near-infrared laser (808 nm). We also demonstrate the means by which the pyroelectric generator can modulate square waveforms with controllable periods through irradiation frequency, which is essential for signal sources and medical stimulators. The overshoot of square waveforms are in a range of 9.0%-13.1% with a rise time of 120 ms. The prepared pyroelectric generator can light a liquid crystal display (LCD) in a vacuum chamber from outside. This work paves the way for non-contact energy harvesting for some particular occasions where near-field energy control is not available.In recent years, energy harvesting technologies, which can scavenge many kinds of energies from our living environment to power micro/nanodevices, have attracted increasing attention. However, remote energy transmission, flexibility and electric waveform controllability remain the key challenges for wireless power supply by an energy harvester. In this paper, we design a new infrared-driven non-contact pyroelectric generator for harvesting heat energy, which avoids direct contact between the pyroelectric generator and heat

Economic and ecological evaluation of biogas plant configurations for a demand oriented biogas supply for flexible power generation

International Nuclear Information System (INIS)

Hahn, Henning

2015-01-01

The transformation of the power supply towards renewable energy (RE) sources will depend on a large scale of fluctuating RE sources, primarily of wind energy and photovoltaics. However, the variable power generation of these renewable sources will lead to an increased need of flexible power producers in order to balance differences between energy generation and consumption. Among the different types of RE sources, biogas plants have the advantage that their input biomass and the produced biogas can be stored and electricity can consequently be generated on demand. Since electricity from biogas has not been used to balance fluctuations of intermittent RE in the past, new concepts are required. These concepts should be able to meet the requirements of highly renewable electricity systems and to supply biogas according to the varying demand for long-and short-term balance power generation. In this regard, this thesis focused on the identification of biogas plant concepts for flexible power generation, as well as on ranking them regarding their economic and life cycle performance.

Economic and ecological evaluation of biogas plant configurations for a demand oriented biogas supply for flexible power generation

Energy Technology Data Exchange (ETDEWEB)

Hahn, Henning

2015-07-01

The transformation of the power supply towards renewable energy (RE) sources will depend on a large scale of fluctuating RE sources, primarily of wind energy and photovoltaics. However, the variable power generation of these renewable sources will lead to an increased need of flexible power producers in order to balance differences between energy generation and consumption. Among the different types of RE sources, biogas plants have the advantage that their input biomass and the produced biogas can be stored and electricity can consequently be generated on demand. Since electricity from biogas has not been used to balance fluctuations of intermittent RE in the past, new concepts are required. These concepts should be able to meet the requirements of highly renewable electricity systems and to supply biogas according to the varying demand for long-and short-term balance power generation. In this regard, this thesis focused on the identification of biogas plant concepts for flexible power generation, as well as on ranking them regarding their economic and life cycle performance.

Grid support by power electronic converters of distributed generation units

NARCIS (Netherlands)

Morren, J.

2006-01-01

An increasing number of small Distributed Generation (DG) units are connected to the grid. The introduction of DG causes several problems, which are mainly related to the differences between DG units and conventional generators. Four problems have been considered in this thesis: damping of

LMFBR steam generators in the United Kingdom

International Nuclear Information System (INIS)

Anderson, R.; Hayden, O.

2002-01-01

Experience has been gained in the UK on the operation of LMFBR Steam Generator Units (SGU) over a period of 20 years from the Dounreay Fast Reactor (DFR) and the Prototype Fast Reactor (PFR). The DFR steam generator featured a double barrier and therefore did not represent a commercial design. PFR, however, faced the challenge of a single wall design and it is experience from this which is most valuable. The PFR reactor went critical in March 1974 and the plant operating history since then has been dominated by experience with leaks in the tube to tube plate welds of the high performance U-tubes SGU's. Operation at high power using the full complement of three secondary sodium circuits was delayed until July 1976 by the occurrence of leaks in the tube to tube plate welds of the superheater and reheater units which are fabricated in stainless steel. Repairs were carried out to the two superheaters and they were returned to service. The reheater tube bundle was removed from circuit after sodium was found to have entered the steam side. When the sodium had been removed and inspection carried out it was decided not to recover the unit. Since 1976 the remaining five stainless steel units have operated satisfactorily. This year a replacement reheater unit has been installed. This is of a new design in 9-Cr-Mo ferritic steel using a sleeve through which the steam tube passes to eliminate the tube to tube plate weld. Despite a few early leaks in evaporator tube to tube plate welds up to 1979, these failures did not initially present a major problem. However, in 1980 the rate of evaporator weld failures increased and despite the successful application of a shot peening process to eliminate stress corrosion failures from the water side of the weld, failures traced to the sodium side continued. A sleeving process was developed for application to complete evaporator units on a production basis with the objective of bypassing the welds at each end of the 500 tubes. The decision

Flexible Biogas in Future Energy Systems—Sleeping Beauty for a Cheaper Power Generation

Directory of Open Access Journals (Sweden)

Markus Lauer

2018-03-01

Full Text Available The increasing proportion of intermittent renewable energies asks for further technologies for balancing demand and supply in the energy system. In contrast to other countries, Germany is characterized by a high installed capacity of dispatchable biogas plants. For this paper, we analyzed the total system costs varying biogas extension paths and modes of operation for the period of 2016–2035 by using a non-linear optimization model. We took variable costs of existing conventional power plants, as well as variable costs and capital investments in gas turbines, Li-ion batteries, and pumped-storage plants into account. Without the consideration of the costs for biogas plants, an increasing proportion of biogas plants, compared to their phase out, reduces the total system costs. Furthermore, their flexible power generation should be as flexible as possible. The lowest total system costs were calculated in an extension path with the highest rate of construction of new biogas plants. However, the highest marginal utility was assessed by a medium proportion of flexible biogas plants. In conclusion, biogas plants can be a cost-effective option to integrate intermittent renewable energies into the electricity system. The optimal extension path of biogas plants depends on the future installed capacities of conventional and renewable energies.

Value of flexible resources, virtual bidding, and self-scheduling in two-settlement electricity markets with wind generation - Part II: ISO Models and Application

DEFF Research Database (Denmark)

Kazempour, Jalal; Hobbs, Benjamin F.

2017-01-01

In Part II of this paper, we present formulations for three two-settlement market models: baseline cost-minimization (Stoch-Opt); and two sequential market models in which an independent system operator (ISO) runs real-time (RT) balancing markets after making day-ahead (DA) generating unit...... commitment decisions based upon deterministic wind forecasts, while virtual bidders arbitrage the two markets (Seq and SeqSS). The latter two models differ in terms of whether some slow-start generators can self-schedule in the DA market while anticipating probabilities of RT prices. Models in Seq and Seq......-SS build on components of the two-settlement equilibrium model (Stoch-MP) defined in Part I of this paper [1]. We then provide numerical results for all four models. A simple single-node case illustrates the economic impacts of flexibility, virtual bidding, and self-schedules, and is followed by a larger...

Non-Relative Value Unit-Generating Activities Represent One-Fifth of Academic Neuroradiologist Productivity.

Science.gov (United States)

Wintermark, M; Zeineh, M; Zaharchuk, G; Srivastava, A; Fischbein, N

2016-07-01

A neuroradiologist's activity includes many tasks beyond interpreting relative value unit-generating imaging studies. Our aim was to test a simple method to record and quantify the non-relative value unit-generating clinical activity represented by consults and clinical conferences, including tumor boards. Four full-time neuroradiologists, working an average of 50% clinical and 50% academic activity, systematically recorded all the non-relative value unit-generating consults and conferences in which they were involved during 3 months by using a simple, Web-based, computer-based application accessible from smartphones, tablets, or computers. The number and type of imaging studies they interpreted during the same period and the associated relative value units were extracted from our billing system. During 3 months, the 4 neuroradiologists working an average of 50% clinical activity interpreted 4241 relative value unit-generating imaging studies, representing 8152 work relative value units. During the same period, they recorded 792 non-relative value unit-generating study reviews as part of consults and conferences (not including reading room consults), representing 19% of the interpreted relative value unit-generating imaging studies. We propose a simple Web-based smartphone app to record and quantify non-relative value unit-generating activities including consults, clinical conferences, and tumor boards. The quantification of non-relative value unit-generating activities is paramount in this time of a paradigm shift from volume to value. It also represents an important tool for determining staffing levels, which cannot be performed on the basis of relative value unit only, considering the importance of time spent by radiologists on non-relative value unit-generating activities. It may also influence payment models from medical centers to radiology departments or practices. © 2016 by American Journal of Neuroradiology.

Comparative life cycle assessment of biogas plant configurations for a demand oriented biogas supply for flexible power generation.

Science.gov (United States)

Hahn, Henning; Hartmann, Kilian; Bühle, Lutz; Wachendorf, Michael

2015-03-01

The environmental performance of biogas plant configurations for a demand - oriented biogas supply for flexible power generation is comparatively assessed in this study. Those configurations indicate an increased energy demand to operate the operational enhancements compared to conventional biogas plants supplying biogas for baseload power generation. However, findings show that in contrast to an alternative supply of power generators with natural gas, biogas supplied on demand by adapted biogas plant configurations saves greenhouse gas emissions by 54-65 g CO(2-eq) MJ(-1) and primary energy by about 1.17 MJ MJ(-1). In this regard, configurations with flexible biogas production profit from reduced biogas storage requirements and achieve higher savings compared to configurations with continuous biogas production. Using thicker biogas storage sheeting material reduces the methane permeability of up to 6m(3) d(-1) which equals a reduction of 8% of the configuration's total methane emissions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Primary separator replacement for Bruce Unit 8 steam generators

International Nuclear Information System (INIS)

Roy, S.B.; Mewdell, C.G.; Schneider, W.G.

2000-01-01

During a scheduled maintenance outage of Bruce Unit 8 in 1998, it was discovered that the majority of the original primary steam separators were damaged in two steam generators. The Bruce B steam generators are equipped with GXP type primary cyclone separators of B and W supply. There were localized perforations in the upper part of the separators and large areas of generalized wall thinning. The degradation was indicative of a flow related erosion corrosion mechanism. Although the unit- restart was justified, it was obvious that corrective actions would be necessary because of the number of separators affected and the extent of the degradation. Repair was not considered to be a practical option and it was decided to replace the separators, as required, in Unit 8 steam generators during an advanced scheduled outage. GXP separators were selected for replacement to minimize the impact on steam generator operating characteristics and analysis. The material of construction was upgraded from the original carbon steel to stainless steel to maximize the assurance of full life. The replacement of the separators was a first of a kind operation not only for Ontario Power Generation and B and W but also for all CANDU plants. The paper describes the degradations observed and the assessments, the operating experience, manufacture and installation of the replacement separators. During routine inspection in 1998, many of the primary steam separators in two of steam generators at Bruce Nuclear Division B Unit 8 were observed to have through wall perforations. This paper describes assessment of this condition. It also discusses the manufacture and testing of replacement primary steam separators and the development and execution of the replacement separator installation program. (author)

A stochastic framework for the grid integration of wind power using flexible load approach

International Nuclear Information System (INIS)

Heydarian-Forushani, E.; Moghaddam, M.P.; Sheikh-El-Eslami, M.K.; Shafie-khah, M.; Catalão, J.P.S.

2014-01-01

Highlights: • This paper focuses on the potential of Demand Response Programs (DRPs) to contribute to flexibility. • A stochastic network constrained unit commitment associated with DR is presented. • DR participation levels and electricity tariffs are evaluated on providing a flexible load profile. • Novel quantitative indices for evaluating flexibility are defined to assess the success of DRPs. • DR types and customer participation levels are the main factors to modify the system load profile. - Abstract: Wind power integration has always been a key research area due to the green future power system target. However, the intermittent nature of wind power may impose some technical and economic challenges to Independent System Operators (ISOs) and increase the need for additional flexibility. Motivated by this need, this paper focuses on the potential of Demand Response Programs (DRPs) as an option to contribute to the flexible operation of power systems. On this basis, in order to consider the uncertain nature of wind power and the reality of electricity market, a Stochastic Network Constrained Unit Commitment associated with DR (SNCUCDR) is presented to schedule both generation units and responsive loads in power systems with high penetration of wind power. Afterwards, the effects of both price-based and incentive-based DRPs are evaluated, as well as DR participation levels and electricity tariffs on providing a flexible load profile and facilitating grid integration of wind power. For this reason, novel quantitative indices for evaluating flexibility are defined to assess the success of DRPs in terms of wind integration. Sensitivity studies indicate that DR types and customer participation levels are the main factors to modify the system load profile to support wind power integration

A Flexible Experimental Laboratory for Distributed Generation Networks Based on Power Inverters

Directory of Open Access Journals (Sweden)

Jaume Miret

2017-10-01

Full Text Available In the recently deregulated electricity market, distributed generation based on renewable sources is becoming more and more relevant. In this area, two main distributed scenarios are focusing the attention of recent research: grid-connected mode, where the generation sources are connected to a grid mainly supplied by big power plants, and islanded mode, where the distributed sources, energy storage devices, and loads compose an autonomous entity that in its general form can be named a microgrid. To conduct a successful research in these two scenarios, it is essential to have a flexible experimental setup. This work deals with the description of a real laboratory setup composed of four nodes that can emulate both scenarios of a distributed generation network. A comprehensive description of the hardware and software setup will be done, focusing especially in the dual-core DSP used for control purposes, which is next to the industry standards and able to emulate real complexities. A complete experimental section will show the main features of the system.

Teaching the basics of electricity using a flexible piezoelectric generator

Science.gov (United States)

Seveno, R.; Dufay, T.; El Gibari, M.; Guiffard, B.; Li, H. W.; Morsli, S.; Pichon, A.; Tanguy, E.

2018-07-01

Lecturer-researchers, because of the duality of their profession, can introduce students directly to their research. Stimulating student interest through practical research topics enables students to see the relevance of the teaching/learning process and thereby enhance their motivation. As a major societal issue, research on renewable energies is held in great esteem, particularly among young students with a strong interest in environmental issues. The work presented here relates to the realization of a practical class on the testing of a flexible piezoelectric generator studied as part of the ‘N-air-J’ regional research project. The particular characteristic of piezoelectric materials is that they produce electricity when compressed, which means that they can be used in energy recovery devices. The electrical model associated with this type of generator, consisting of an ideal current source in parallel with a linear capacitor and a load resistor, is sufficiently simple to understand following a course on electricity for first-year university students. High school students in their first year of a science and laboratory technology baccalaureate in France have already taken this practical class as part of a dissemination campaign on scientific culture.

Installation of new Generation General Purpose Computer (GPC) compact unit

Science.gov (United States)

1991-01-01

In the Kennedy Space Center's (KSC's) Orbiter Processing Facility (OPF) high bay 2, Spacecraft Electronics technician Ed Carter (right), wearing clean suit, prepares for (26864) and installs (26865) the new Generation General Purpose Computer (GPC) compact IBM unit in Atlantis', Orbiter Vehicle (OV) 104's, middeck avionics bay as Orbiter Systems Quality Control technician Doug Snider looks on. Both men work for NASA contractor Lockheed Space Operations Company. All three orbiters are being outfitted with the compact IBM unit, which replaces a two-unit earlier generation computer.

The object classification task for children: A new measure of concept generation and mental flexibility in early childhood

OpenAIRE

Smidts, D.P.; Jacobs, R.; Anderson, V.

2004-01-01

In this study, the development of concept generation and mental flexibility was investigated in 84 Australian children between 3 and 7 years of age, using the Object Classification Task for Children (OCTC), a newly developed executive function test for use with young children. On this task, which was adapted from the Concept Generation Test (Levine, Stuss, & Milberg, 1995) and the Concept Generation Test for Children (Jacobs, Anderson, & Harvey, 2001), children were asked to categorize 6 plas...

Mathematical modeling of a fast-breeder-reactor generating unit

International Nuclear Information System (INIS)

Kim, V.E.; Golovach, E.A.; Senkin, V.I.

1984-01-01

Dynamics equations are given for a reactor, intermediate heat exchanger, steam generator, and turbogenerator. The dynamic characteristics of the generating unit are described when perturbations occur in grid frequency, turbine valves, and feedwater consumption

A comprehensive study of economic unit commitment of power systems integrating various renewable generations and plug-in electric vehicles

International Nuclear Information System (INIS)

Yang, Zhile; Li, Kang; Niu, Qun; Xue, Yusheng

2017-01-01

Highlights: • A new UCsRP problem with flexible integrations is established. • A novel multi-zone sampling method is proposed for scenarios generation. • A meta-heuristic solving tool is introduced for solving the UCsRP problem. • A comprehensive study is conducted considering multiple weathers and seasons. • The economic effects of various scenarios are evaluated and compared. - Abstract: Significant penetration of renewable generations (RGs) and mass roll-out of plug-in electric vehicles (PEVs) will pay a vital role in delivering the low carbon energy future and low emissions of greenhouse gas (GHG) that are responsible for the global climate change. However, it is of considerable difficulties to precisely forecast the undispatchable and intermittent wind and solar power generations. The uncoordinated charging of PEVs imposes further challenges on the unit commitment in modern grid operations. In this paper, all these factors are comprehensively investigated for the first time within a novel hybrid unit commitment framework, namely UCsRP, which considers a wide range of scenarios in renewable generations and demand side management of dispatchable PEVs load. UCsRP is however an extremely challenging optimisation problem not only due to the large scale, mixed integer and nonlinearity, but also due to the double uncertainties relating to the renewable generations and PEV charging and discharging. In this paper, a meta-heuristic solving tool is introduced for solving the UCsRP problem. A key to improve the reliability of the unit commitment is to generate a range of scenarios based on multiple distributions of renewable generations under different prediction errors and extreme predicted value conditions. This is achieved by introducing a novel multi-zone sampling method. A comprehensive study considering four different cases of unit commitment problems with various weather and season scenarios using real power system data are conducted and solved, and smart

Power quality improvement of unbalanced power system with distributed generation units

DEFF Research Database (Denmark)

Hu, Y.; Chen, Zhe; Excell, P.

2011-01-01

This paper presents a power electronic system for improving the power quality of the unbalanced distributed generation units in three-phase four-wire system. In the system, small renewable power generation units, such as small PV generator, small wind turbines may be configured as single phase...... and control of the converter are described. Simulation results have demonstrated that the system can effectively correct the unbalance and enhance the system power quality....... generation units. The random nature of renewable power sources may result in significant unbalance in the power network and affect the power quality. An electronic converter system is proposed to correct the system unbalance and harmonics so as to deal with the power quality problems. The operation...

North Anna Power Station - Unit 1: Overview of steam generator replacement project activities

International Nuclear Information System (INIS)

Gettler, M.W.; Bayer, R.K.; Lippard, D.W.

1993-01-01

The original steam generators at Virginia Electric and Power Company's (Virginia Power) North Anna Power Station (NAPS) Unit 1 have experienced corrosion-related degradation that require periodic inspection and plugging of steam generator tubes to ensure their continued safe and reliable operation. Despite improvements in secondary water chemistry, continued tube degradation in the steam generators necessitated the removal from service of approximately 20.3 percent of the tubes by plugging, (18.6, 17.3, and 25.1 for steam generators A, B, and C, respectively). Additionally, the unit power was limited to 95 % during, its last cycle of operation. Projections of industry and Virginia Power experience indicated the possibility of mid-cycle inspections and reductions in unit power. Therefore, economic considerations led to the decision to repair the steam generators (i.e., replace the steam generator lower assemblies). Three new Model 51F Steam Generator lower assembly units were ordered from Westinghouse. Virginia Power contracted Bechtel Power Corporation to provide the engineering and construction support to repair the Unit 1 steam generators. On January 4, 1993, after an extended coastdown period, North Anna Unit 1 was brought off-line and the 110 day (breaker-to-breaker) Steam Generator Replacement Project (SGRP) outage began. As of this paper, the outage is still in progress

Demand for flexibility or generation of insecurity? The individualization of risk, irregular work shifts and Canadian youth

NARCIS (Netherlands)

Mills, M.C.

2004-01-01

The individualization of risk is alleged to have generated a rise in flexible and insecure forms of non-standard employment, which in turn create 'new inequalities and insecurities' that permeate all social groups. Using longitudinal data from the Canadian Survey of Labour and Income Dynamics

Multi-Unit Aspects of the Pickering Generating Station

Energy Technology Data Exchange (ETDEWEB)

Morison, W. G. [Atomic Energy of Canada Ltd, Sheridan Park, ON (Canada)

1968-04-15

The Pickering nuclear generating station is located on the north shore of Lake Ontario, about 20 miles east of the city of Toronto, Canada. The station has been planned and laid out on an eight-unit station, four units of which have now been authorized for construction. Each of these four units consists of a single heavy-water moderated and cooled CANDU-type reactor and auxiliaries coupled to a single tandem compound turbine generator with a net output of approximately 500 MW(e). The units are identical and are scheduled to come into operation at intervals of one year from 1970 to 1973. The station has been planned with central facilities for: administration maintenance laboratories, stores, change rooms, decontamination and waste management services. A common control centre, cooling water intake and discharge system, and spent fuel storage bay for four units has been arranged. A feature of the multi-unit station is a common containment system. Cost savings in building a number of identical units on the same site result from a single exclusion area, shared engineering costs, equipment purchase contracts for four identical components, and efficient use of construction plant. Operating cost savings are anticipated in the use of a common operating and maintenance staff and spare parts inventory. The plant has been arranged to minimize problems of operating, commissioning and constructing units at the same time on the same site. The layout and construction sequence have been arranged so that the first unit can be commissioned and operated with little or no interference from the construction forces working on succeeding units. During the construction phase barriers will be erected in the common control centre between operating control equipment and that being installed. Operations and construction personnel will enter the plant by separate routes and work in areas separated by physical barriers. (author)

Highly Flexible, Fire Resistant HybridSil Foams for Next Generation Fireproofing, Insulation, and Energy Absorption NASA Applications, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The objective of this Phase I STTR program is to adapt NanoSonic's HybridSil™ nanocomposite technology for the creation of next generation highly flexible, fire...

Techno-economic optimization of flexible biogas concepts in the context of EEG

International Nuclear Information System (INIS)

Barchmann, Tino; Lauer, Markus

2014-01-01

Due to the introduction of direct marketing and flexibility premium of renewable energy by the Renewable Energy Act 2012 (EEG 2012), incentives were created to favour a more demand-oriented power supply from biogas plants (BGA). The decision for such an operational mode depends on on-site conversion units on the economic outcome of the plants throughout the whole operating time. To install new plants or transfer existing plants into a flexible mode of operation, investments in additional and more efficient combined heat and power plants (CHP), in additional gas and/or heat storage and other technical components are necessary. The analyses show that the flexibility premium, as an extra of the market premium model, creates the greatest incentive for a more flexible generation of electricity from biogas. In addition, an intelligent management optimization can generate additional revenues on EPEX SPOT SE and balancing energy market. The additional revenues of more demand-oriented power supply from biogas plants are highly dependent on plant-specific conditions. From an economic perspective, a duplication of the installed electrical capacity seems to be the most beneficial option for a transition to a demand-driven operation mode of an average biogas model plant under the current legal framework (EEG 2012).

Flexible lithium-ion planer thin-film battery

KAUST Repository

Kutbee, Arwa T.; Ghoneim, Mohamed T.; Hussain, Muhammad Mustafa

2016-01-01

Commercialization of wearable electronics requires miniaturized, flexible power sources. Lithium ion battery is a strong candidate as the next generation high performance flexible battery. The development of flexible materials for battery electrodes

Study of Flexible Load Dispatch to Improve the Capacity of Wind Power Absorption

Science.gov (United States)

Yunlei, Yang; Shifeng, Zhang; Xiao, Chang; Da, Lei; Min, Zhang; Jinhao, Wang; Shengwen, Li; Huipeng, Li

2017-05-01

The dispatch method which track the trend of load demand by arranging the generation scheme of controllable hydro or thermal units faces great difficulties and challenges. With the increase of renewable energy sources such as wind power and photovoltaic power introduced to grid, system has to arrange much more spinning reserve units to compensate the unbalanced power. How to exploit the peak-shaving potential of flexible load which can be shifted with time or storage energy has become many scholars’ research direction. However, the modelling of different kinds of load and control strategy is considerably difficult, this paper choose the Air Conditioner with compressor which can storage energy in fact to study. The equivalent thermal parameters of Air Conditioner has been established. And with the use of “loop control” strategies, we can predict the regulated power of Air Conditioner. Then we established the Gen-Load optimal scheduling model including flexible load based on traditional optimal scheduling model. At last, an improved IEEE-30 case is used to verify. The result of simulation shows that flexible load can fast-track renewable power changes. More than that, with flexible load and reasonable incentive method to consumers, the operating cost of the system can be greatly cut down.

Impact of distributed generation units with power electronic converters on distribution network protection

NARCIS (Netherlands)

Morren, J.; Haan, de S.W.H.

2008-01-01

An increasing number of distributed generation units (DG units) are connected to the distribution network. These generators affect the operation and coordination of the distribution network protection. The influence from DG units that are coupled to the network with a power electronic converter

AIR POLLUTION: Emissions from Older Electricity Generating Units

National Research Council Canada - National Science Library

2002-01-01

.... While fossil fuels-coal, natural gas, and oil-account for more than two thirds of our electricity, generating units that burn these fuels are major sources of airborne emissions that pose human...

Sources of Operational Flexibility, Greening the Grid

Energy Technology Data Exchange (ETDEWEB)

Katz, Jessica; Milligan, Michael; Cochran, Jaquelin

2015-05-01

Changes in electricity demand and generation must be constantly balanced to maintain power system stability and reliability. Operational flexibility refers to the ability of a power system to respond to these changes. Power systems are designed and operated to efficiently manage variability and uncertainty in electricity demand and resource availability. Variable renewable energy (VRE) increases this inherent variability and uncertainty, and thus increases the need for flexibility. Systems with significant variability and uncertainty require flexible generators that can rapidly change output, operate efficiently at lower outputs, and operate for short durations. This flexibility in turn can reduce the need to curtail (decrease the output of) solar and wind generation; improve investor confidence in VRE and revenue streams; decrease the risk of negative market pricing (which results when conventional generators cannot turn down to low outputs during times of high VRE output); and reduce environmental impacts by increasing system efficiency and maximizing the utilization of VRE.

Improvement in PWR flexibility the french program 1975-1995

International Nuclear Information System (INIS)

Gautier, A.; Miossec, C.

1985-12-01

Between 1975 and 1985, a substantial effort was launched in France to greatly improve PWR's flexibility, resulting in the current situation where both frequency control and load follow are now routinely performed on most plants in operation. Based on rapidly accumulating operational experience and on all expertise acquired in the past decade, a second-generation core control strategy is now being finalized for application on all future 1400 MW plants (with commercial operation scheduled in 1992 for first unit). This 20-year program is discussed

Column generation approaches to ship scheduling with flexible cargo sizes

DEFF Research Database (Denmark)

Brønmo, Geir; Nygreen, Bjørn; Lysgaard, Jens

We present a Dantzig-Wolfe procedure for the ship scheduling problem with flexible cargo sizes. This problem is similar to the well-known pickup and delivery problem with time windows, but the cargo sizes are defined by an interval instead of a fixed value. We show that the introduction of flexible...

The object classification task for children: A new measure of concept generation and mental flexibility in early childhood

NARCIS (Netherlands)

Smidts, D.P.; Jacobs, R.; Anderson, V.

2004-01-01

In this study, the development of concept generation and mental flexibility was investigated in 84 Australian children between 3 and 7 years of age, using the Object Classification Task for Children (OCTC), a newly developed executive function test for use with young children. On this task, which

Assess and Predict Automatic Generation Control Performances for Thermal Power Generation Units Based on Modeling Techniques

Science.gov (United States)

Zhao, Yan; Yang, Zijiang; Gao, Song; Liu, Jinbiao

2018-02-01

Automatic generation control(AGC) is a key technology to maintain real time power generation and load balance, and to ensure the quality of power supply. Power grids require each power generation unit to have a satisfactory AGC performance, being specified in two detailed rules. The two rules provide a set of indices to measure the AGC performance of power generation unit. However, the commonly-used method to calculate these indices is based on particular data samples from AGC responses and will lead to incorrect results in practice. This paper proposes a new method to estimate the AGC performance indices via system identification techniques. In addition, a nonlinear regression model between performance indices and load command is built in order to predict the AGC performance indices. The effectiveness of the proposed method is validated through industrial case studies.

Enhanced Control for a Direct-driven Permanent Synchronous Generator Wind-power Generation System with Flywheel Energy Storage Unit Under Unbalanced Grid Fault

DEFF Research Database (Denmark)

Yao, Jun; Zhou, Te; Hu, Weihao

2015-01-01

This article presents an enhanced control strategy for a direct-driven permanent synchronous generator based wind-power generation system with a flywheel energy storage unit. The behaviors of the direct-driven permanent magnet synchronous generator system with a flywheel energy storage unit under......, the DC-link voltage oscillations can be effectively suppressed during the unbalanced grid fault by controlling the flywheel energy storage unit. Furthermore, a proportional–integral-resonant controller is designed for the flywheel motor to eliminate the oscillations in the DC-link voltage. Finally......, the proposed coordinated control strategy for the direct-driven permanent magnet synchronous generator system with a flywheel energy storage unit has been validated by the simulation results of a 1-MW direct-driven permanent magnet synchronous generator wind power generation system with a flywheel energy...

Business Models for Power System Flexibility

DEFF Research Database (Denmark)

Boscan, Luis; Poudineh, Rahmatallah

2016-01-01

As intermittent, renewable resources gain more share in the generation mix, the need for power system flexibility increases more than ever. Parallel to this, technological change and the emergence of new players bringing about innovative solutions are boosting the development of flexibility...... business models will play an important role in ensuring sufficiency and efficiency of flexibility services....

A flexible optically re-writable color liquid crystal display

Science.gov (United States)

Zhang, Yihong; Sun, Jiatong; Liu, Yang; Shang, Jianhua; Liu, Hao; Liu, Huashan; Gong, Xiaohui; Chigrinov, Vladimir; Kowk, Hoi Sing

2018-03-01

It is very difficult to make a liquid crystal display (LCD) that is flexible. However, for an optically re-writable LCD (ORWLCD), only the spacers and the substrates need to be flexible because the driving unit and the display unit are separate and there are no electronics in the display part of ORWLCD. In this paper, three flexible-spacer methods are proposed to achieve this goal. A cholesteric liquid crystal colored mirror with a polarizer behind it is used as the colored reflective backboard of an ORWLCD. Polyethersulfone substrates and flexible spacers are used to make the optically re-writable cell insensitive to mechanical force.

Decentralized Voltage Control Coordination of On-Load Tap Changer Transformers, Distributed Generation Units and Flexible Loads

DEFF Research Database (Denmark)

Romani Dalmau, Aina; Martinez Perez, David; Diaz de Cerio Mendaza, Iker

2015-01-01

The increase of distributed generation is expected to generate instabilities, such as power imbalances or voltage deviations in the power system. At the distribution level, maintaining the bus voltages within the stipulated limits is one of the major challenges for the distribution system operator....... Under low penetration levels, several voltage regulation elements have been efficiently employed up to now. However, under large distributed generation levels, the traditional techniques have to be coordinated with new upcoming solutions, such us demand response. In this paper a simple and decentralized...... of the on-load tap changer and the reactive power from dispersed generation while maximizing the capacity usage of the Power-to-Gas load....

Energy Flexibility in the Power System

DEFF Research Database (Denmark)

Billanes, Joy Dalmacio; Ma, Zheng; Jørgensen, Bo Nørregaard

2017-01-01

Energy flexibility can address the challenges of large scale integration of renewable energy resources and thereby increasing imbalance in the power system. Flexible power system can provide reliable supply, low electricity cost and sustainability. Various situations and factors influence...... the adoption of the flexibility solutions, such as flexible electricity generation, demand-response, and electricity storage. This paper tries to analyze the current energy flexibility solutions and the factors that can influence the energy flexibility adoption. This paper takes Philippines as case study...... to provide an overview of the current condition of the Philippines’ power system and discuss the energy flexibility in the Philippines’ power system. A further discussion and recommendation is conducted in the end of the paper....

Development of flexible, free-standing, thin films for additive manufacturing and localized energy generation

Energy Technology Data Exchange (ETDEWEB)

Clark, Billy; McCollum, Jena; Pantoya, Michelle L., E-mail: michelle.pantoya@ttu.edu [Mechanical Engineering Department, Texas Tech University, Lubbock TX 79409 (United States); Heaps, Ronald J.; Daniels, Michael A. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415 (United States)

2015-08-15

Film energetics are becoming increasingly popular because a variety of technologies are driving a need for localized energy generation in a stable, safe and flexible form. Aluminum (Al) and molybdenum trioxide (MoO{sub 3}) composites were mixed into a silicon binder and extruded using a blade casting technique to form flexible free-standing films ideal for localized energy generation. Since this material can be extruded onto a surface it is well suited to additive manufacturing applications. This study examines the influence of 0-35% by mass potassium perchlorate (KClO{sub 4}) additive on the combustion behavior of these energetic films. Without KClO{sub 4} the film exhibits thermal instabilities that produce unsteady energy propagation upon reaction. All films were cast at a thickness of 1 mm with constant volume percent solids to ensure consistent rheological properties. The films were ignited and flame propagation was measured. The results show that as the mass percent KClO{sub 4} increased, the flame speed increased and peaked at 0.43 cm/s and 30 wt% KClO{sub 4}. Thermochemical equilibrium simulations show that the heat of combustion increases with increasing KClO{sub 4} concentration up to a maximum at 20 wt% when the heat of combustion plateaus, indicating that the increased chemical energy liberated by the additional KClO{sub 4} promotes stable energy propagation. Differential scanning calorimeter and thermogravimetric analysis show that the silicone binder participates as a fuel and reacts with KClO{sub 4} adding energy to the reaction and promoting propagation.

Development of flexible, free-standing, thin films for additive manufacturing and localized energy generation

Directory of Open Access Journals (Sweden)

Billy Clark

2015-08-01

Full Text Available Film energetics are becoming increasingly popular because a variety of technologies are driving a need for localized energy generation in a stable, safe and flexible form. Aluminum (Al and molybdenum trioxide (MoO3 composites were mixed into a silicon binder and extruded using a blade casting technique to form flexible free-standing films ideal for localized energy generation. Since this material can be extruded onto a surface it is well suited to additive manufacturing applications. This study examines the influence of 0-35% by mass potassium perchlorate (KClO4 additive on the combustion behavior of these energetic films. Without KClO4 the film exhibits thermal instabilities that produce unsteady energy propagation upon reaction. All films were cast at a thickness of 1 mm with constant volume percent solids to ensure consistent rheological properties. The films were ignited and flame propagation was measured. The results show that as the mass percent KClO4 increased, the flame speed increased and peaked at 0.43 cm/s and 30 wt% KClO4. Thermochemical equilibrium simulations show that the heat of combustion increases with increasing KClO4 concentration up to a maximum at 20 wt% when the heat of combustion plateaus, indicating that the increased chemical energy liberated by the additional KClO4 promotes stable energy propagation. Differential scanning calorimeter and thermogravimetric analysis show that the silicone binder participates as a fuel and reacts with KClO4 adding energy to the reaction and promoting propagation.

Multi Agent System Based Adaptive Protection for Dispersed Generation Integrated Distribution Systems

DEFF Research Database (Denmark)

Liu, Leo; Rather, Zakir Hussain; Bak, Claus Leth

2013-01-01

The increasing penetration of dispersed generation (DG) brings challenges to conventional protection approaches of distribution system, mainly due to bi-directional power flow and variable fault current contribution from different generation technology-based DG units. Moreover, the trend......) is proposed. The adaptive protection intelligently adopts suitable settings for the variation of fault current from diversified DG units. Furthermore, the structure of mobile MAS with additional flexibility is capable of adapting the changes of system topology in a short period, e.g. radial/meshed, grid...

Sensor Technologies on Flexible Substrates

Science.gov (United States)

Koehne, Jessica

2016-01-01

NASA Ames has developed sensor technologies on flexible substrates integrated into textiles for personalized environment monitoring and human performance evaluation. Current technologies include chemical sensing for gas leak and event monitoring and biological sensors for human health and performance monitoring. Targeted integration include next generation EVA suits and flexible habitats.

76 FR 19148 - PSEG Nuclear, LLC, Hope Creek Generating Station and Salem Nuclear Generating Station, Units 1...

Science.gov (United States)

2011-04-06

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-272, 50-311, 50-354; NRC-2009-0390 and NRC-2009-0391] PSEG Nuclear, LLC, Hope Creek Generating Station and Salem Nuclear Generating Station, Units 1 and 2..., DPR-70, and DPR-75 for an additional 20 years of operation for the Hope Creek Generating Station (HCGS...

Load and Flexibility Models for Distribution Grid Management

DEFF Research Database (Denmark)

Kouzelis, Konstantinos

to advanced metering and control infrastructure investments. These investments will transform distribution networks into smarter" grids which will facilitate flexible load/generation control in return for financial and reliability benefits to electricity consumers. The theoretical idea of modernising the grid...... involve lack of generic load forecasts, need for flexible load/generation estimation techniques from smart meter measurements, deficiencies in online load distribution observability, and, finally, energy market compatible control algorithms which treat consumer flexibility in a fair manner. These modules...... congestions, is proposed. In the first step, a central controller manages flexibility proactively, whereas in the second step a decentralised control scheme deals with flexibility reactively. Both controllers are designed in such a way, that compatibility with contemporary markets is assured, while special...

Development of Nuclear Renewable Oil Shale Systems for Flexible Electricity and Reduced Fossil Fuel Emissions

Energy Technology Data Exchange (ETDEWEB)

Daniel Curtis; Charles Forsberg; Humberto Garcia

2015-05-01

We propose the development of Nuclear Renewable Oil Shale Systems (NROSS) in northern Europe, China, and the western United States to provide large supplies of flexible, dispatchable, very-low-carbon electricity and fossil fuel production with reduced CO2 emissions. NROSS are a class of large hybrid energy systems in which base-load nuclear reactors provide the primary energy used to produce shale oil from kerogen deposits and simultaneously provide flexible, dispatchable, very-low-carbon electricity to the grid. Kerogen is solid organic matter trapped in sedimentary shale, and large reserves of this resource, called oil shale, are found in northern Europe, China, and the western United States. NROSS couples electricity generation and transportation fuel production in a single operation, reduces lifecycle carbon emissions from the fuel produced, improves revenue for the nuclear plant, and enables a major shift toward a very-low-carbon electricity grid. NROSS will require a significant development effort in the United States, where kerogen resources have never been developed on a large scale. In Europe, however, nuclear plants have been used for process heat delivery (district heating), and kerogen use is familiar in certain countries. Europe, China, and the United States all have the opportunity to use large scale NROSS development to enable major growth in renewable generation and either substantially reduce or eliminate their dependence on foreign fossil fuel supplies, accelerating their transitions to cleaner, more efficient, and more reliable energy systems.

Backup flexibility classes in emerging large-scale renewable electricity systems

International Nuclear Information System (INIS)

Schlachtberger, D.P.; Becker, S.; Schramm, S.; Greiner, M.

2016-01-01

Highlights: • Flexible backup demand in a European wind and solar based power system is modelled. • Three flexibility classes are defined based on production and consumption timescales. • Seasonal backup capacities are shown to be only used below 50% renewable penetration. • Large-scale transmission between countries can reduce fast flexible capacities. - Abstract: High shares of intermittent renewable power generation in a European electricity system will require flexible backup power generation on the dominant diurnal, synoptic, and seasonal weather timescales. The same three timescales are already covered by today’s dispatchable electricity generation facilities, which are able to follow the typical load variations on the intra-day, intra-week, and seasonal timescales. This work aims to quantify the changing demand for those three backup flexibility classes in emerging large-scale electricity systems, as they transform from low to high shares of variable renewable power generation. A weather-driven modelling is used, which aggregates eight years of wind and solar power generation data as well as load data over Germany and Europe, and splits the backup system required to cover the residual load into three flexibility classes distinguished by their respective maximum rates of change of power output. This modelling shows that the slowly flexible backup system is dominant at low renewable shares, but its optimized capacity decreases and drops close to zero once the average renewable power generation exceeds 50% of the mean load. The medium flexible backup capacities increase for modest renewable shares, peak at around a 40% renewable share, and then continuously decrease to almost zero once the average renewable power generation becomes larger than 100% of the mean load. The dispatch capacity of the highly flexible backup system becomes dominant for renewable shares beyond 50%, and reach their maximum around a 70% renewable share. For renewable shares

Electricity market design for generator revenue sufficiency with increased variable generation

International Nuclear Information System (INIS)

Levin, Todd; Botterud, Audun

2015-01-01

We present a computationally efficient mixed-integer program (MIP) that determines optimal generator expansion decisions, and hourly unit commitment and dispatch in a power system. The impact of increasing wind power capacity on the optimal generation mix and generator profitability is analyzed for a test case that approximates the electricity market in Texas (ERCOT). We analyze three market policies that may support resource adequacy: Operating Reserve Demand Curves (ORDC), Fixed Reserve Scarcity Prices (FRSP) and fixed capacity payments (CP). Optimal expansion plans are comparable between the ORDC and FRSP implementations, while capacity payments may result in additional new capacity. The FRSP policy leads to frequent reserves scarcity events and corresponding price spikes, while the ORDC implementation results in more continuous energy prices. Average energy prices decrease with increasing wind penetration under all policies, as do revenues for baseload and wind generators. Intermediate and peak load plants benefit from higher reserve prices and are less exposed to reduced energy prices. All else equal, an ORDC approach may be preferred to FRSP as it results in similar expansion and revenues with less extreme energy prices. A fixed CP leads to additional new flexible NGCT units, but lower profits for other technologies. - Highlights: • We model three market policies for resource adequacy in power systems with wind. • Unit expansion is comparable between ORDCs and fixed reserves scarcity pricing. • ORDCs lead to a more continuous spectrum of energy prices and fewer price spikes. • Revenues for baseload generators generally decrease with increasing wind penetration. • Capacity payments lead to additional NGCT units and lower energy prices.

Meteosat third generation imager: simulation of the flexible combined imager instrument chain

Science.gov (United States)

Just, Dieter; Gutiérrez, Rebeca; Roveda, Fausto; Steenbergen, Theo

2014-10-01

The Meteosat Third Generation (MTG) Programme is the next generation of European geostationary meteorological systems. The first MTG satellite, MTG-I1, which is scheduled for launch at the end of 2018, will host two imaging instruments: the Flexible Combined Imager (FCI) and the Lightning Imager. The FCI will provide continuation of the SEVIRI imager operations on the current Meteosat Second Generation satellites (MSG), but with an improved spatial, temporal and spectral resolution, not dissimilar to GOES-R (of NASA/NOAA). Unlike SEVIRI on the spinning MSG spacecraft, the FCI will be mounted on a 3-axis stabilised platform and a 2-axis tapered scan will provide a full coverage of the Earth in 10 minute repeat cycles. Alternatively, a rapid scanning mode can cover smaller areas, but with a better temporal resolution of up to 2.5 minutes. In order to assess some of the data acquisition and processing aspects which will apply to the FCI, a simplified end-to-end imaging chain prototype was set up. The simulation prototype consists of four different functional blocks: - A function for the generation of FCI-like references images - An image acquisition simulation function for the FCI Line-of-Sight calculation and swath generation - A processing function that reverses the swath generation process by rectifying the swath data - An evaluation function for assessing the quality of the processed data with respect to the reference images This paper presents an overview of the FCI instrument chain prototype, covering instrument characteristics, reference image generation, image acquisition simulation, and processing aspects. In particular, it provides in detail the description of the generation of references images, highlighting innovative features, but also limitations. This is followed by a description of the image acquisition simulation process, and the rectification and evaluation function. The latter two are described in more detail in a separate paper. Finally, results

Harnessing the Flexibility of Thermostatic Loads in Microgrids with Solar Power Generation

Directory of Open Access Journals (Sweden)

Rosa Morales González

2016-07-01

Full Text Available This paper presents a demand response (DR framework that intertwines thermodynamic building models with a genetic algorithm (GA-based optimization method. The framework optimizes heating/cooling schedules of end-users inside a business park microgrid with local distributed generation from renewable energy sources (DG-RES based on two separate objectives: net load minimization and electricity cost minimization. DG-RES is treated as a curtailable resource in anticipation of future scenarios where the infeed of DG-RES to the regional distribution network could be limited. We test the DR framework with a case study of a refrigerated warehouse and an office building located in a business park with local PV generation. Results show the technical potential of the DR framework in harnessing the flexibility of the thermal masses from end-user sites in order to: (1 reduce the energy exchange at the point of connection; (2 reduce the cost of electricity for the microgrid end-users; and (3 increase the local utilization of DG-RES in cases where DG-RES exports to the grid are restricted. The results of this work can aid end-users and distribution network operators to reduce energy costs and energy consumption.

Flexible lithium-ion planer thin-film battery

KAUST Repository

Kutbee, Arwa T.

2016-02-03

Commercialization of wearable electronics requires miniaturized, flexible power sources. Lithium ion battery is a strong candidate as the next generation high performance flexible battery. The development of flexible materials for battery electrodes suffers from the limited material choices. In this work, we present a flexible inorganic lithium-ion battery with no restrictions on the materials used. The battery showed an enhanced normalized capacity of 146 ??Ah/cm2.

STARTER-GENERATOR SYSTEM FOR AUXILIARY POWER UNIT

Directory of Open Access Journals (Sweden)

A. V. Levin

2017-01-01

Full Text Available The article presents a starter-generator system for an auxiliary power unit of an aircraft. A feature of the presented system is the use of a synchronous generator with excitation from permanent magnets and a semiconductor converter. The main problem of the system is the generation of electric energy of an aircraft on the basis of a synchronous generator with excitation from permanent magnets is the absence of the possibility of regulating the voltage and frequency of electrical energy, in this connection, a semiconductor converter that ensures the conversion of generated electric energy with significant mass-dimensions characteristics.The article proposes an approach to designing a starter-generator system with a parallel connection of a synchronous generator with excitation from permanent magnets and a semiconductor converter. This approach makes it possible to significantly reduce the part of the electrical energy that needs to be converted, as a consequence, the semiconductor converter has significantly smaller mass-and-batch characteristics.In the article the modes of generation of electric energy and the starter mode of operation of the starter-generator system are considered in detail, the circuit realization of the semiconductor converter is shown. A scheme for replacing one phase of the system for generating electric energy and calculating electric parameters is presented.The possibility of creating a highly efficient starter-generator system based on a synchronous generator with excitation from permanent magnets and a semiconductor converter for an auxiliary power plant of aircrafts is shown. Structural and basic schemes for constructing a system for generating electrical energy are proposed. The approach to the choice of rational circuit solutions is substantiated, basic estimates of the electrical parameters of the system are obtained. The possibility of achieving a specific mass of a semiconductor converter for synchronous

Cernavoda NPP Unit 1 - a plant of several generations

International Nuclear Information System (INIS)

Rotaru, I.; Metes, M.; Anghelescu, M.S.

2000-01-01

Cernavoda NPP Unit 1, the first nuclear power unit in Romania, has a long and tormented history. It represents a rather unique case in Eastern Europe. The project started well before 1989 (the construction phase lasted 17 years and generations were involved in its completion), but it is effectively based on western technology (Candu). Meanwhile, the national nuclear program underwent many changes, affecting the lives and careers of Romanian nuclear professionals. Finally, on December 2 nd 1996, the unit began its c ommercial operation , being operated at its nominal power rating of 706 MW e . It now provides a reliable source of electricity for Romanian economy, supplying to the national grid about 10% of the country's average annual demand. The paper reflects some aspects related to the shift of generations during the project's development, including the present stage. The operational performances achieved 'in service' by Cernavoda NPP Unit 1 up to the end of 1999 , are also presented. Reference to the electrical energy production, performance indicators, production costs, nuclear safety, radiation protection, radioactive wastes, nuclear fuel consumption and nuclear fuel performances are included. Comparisons are performed with similar indicators reported by other worldwide nuclear power plants, in order to assess our results. (authors)

Characterization of the Advanced Stirling Radioisotope Generator Engineering Unit 2

Science.gov (United States)

Lewandowski, Edward J.; Oriti, Salvatore M.; Schifer, Niholas A.

2016-01-01

Significant progress was made developing the Advanced Stirling Radioisotope Generator (ASRG) 140-W radioisotope power system. While the ASRG flight development project has ended, the hardware that was designed and built under the project is continuing to be tested to support future Stirling-based power system development. NASA Glenn Research Center recently completed the assembly of the ASRG Engineering Unit 2 (EU2). The ASRG EU2 consists of the first pair of Sunpower's Advanced Stirling Convertor E3 (ASC-E3) Stirling convertors mounted in an aluminum housing, and Lockheed Martin's Engineering Development Unit (EDU) 4 controller (a fourth-generation controller). The ASC-E3 convertors and Generator Housing Assembly (GHA) closely match the intended ASRG Qualification Unit flight design. A series of tests were conducted to characterize the EU2, its controller, and the convertors in the flight-like GHA. The GHA contained an argon cover gas for these tests. The tests included measurement of convertor, controller, and generator performance and efficiency; quantification of control authority of the controller; disturbance force measurement with varying piston phase and piston amplitude; and measurement of the effect of spacecraft direct current (DC) bus voltage on EU2 performance. The results of these tests are discussed and summarized, providing a basic understanding of EU2 characteristics and the performance and capability of the EDU 4 controller.

ACO-Initialized Wavelet Neural Network for Vibration Fault Diagnosis of Hydroturbine Generating Unit

Directory of Open Access Journals (Sweden)

Zhihuai Xiao

2015-01-01

Full Text Available Considering the drawbacks of traditional wavelet neural network, such as low convergence speed and high sensitivity to initial parameters, an ant colony optimization- (ACO- initialized wavelet neural network is proposed in this paper for vibration fault diagnosis of a hydroturbine generating unit. In this method, parameters of the wavelet neural network are initialized by the ACO algorithm, and then the wavelet neural network is trained by the gradient descent algorithm. Amplitudes of the frequency components of the hydroturbine generating unit vibration signals are used as feature vectors for wavelet neural network training to realize mapping relationship from vibration features to fault types. A real vibration fault diagnosis case result of a hydroturbine generating unit shows that the proposed method has faster convergence speed and stronger generalization ability than the traditional wavelet neural network and ACO wavelet neural network. Thus it can provide an effective solution for online vibration fault diagnosis of a hydroturbine generating unit.

Advanced Stirling Radioisotope Generator Engineering Unit 2 Anomaly Investigation

Science.gov (United States)

Lewandowski, Edward J.; Dobbs, Michael W.; Oriti, Salvatore M.

2018-01-01

The Advanced Stirling Radioisotope Generator (ASRG) Engineering Unit 2 (EU2) is the highest fidelity electrically heated Stirling radioisotope generator built to date. NASA Glenn Research Center completed the assembly of the ASRG EU2 in September 2014 using hardware from the now cancelled ASRG flight development project. The ASRG EU2 integrated the first pair of Sunpower's Advanced Stirling Convertors (ASC-E3 #1 and #2) in an aluminum generator housing with Lockheed Martin's (LM's) Engineering Development Unit (EDU) 4 controller. After just 179 hr of EU2 generator operation, the first power fluctuation occurred on ASC-E3 #1. The first power fluctuation occurred 175 hr later on ASC-E3 #2. Over time, the power fluctuations became more frequent on both convertors and larger in magnitude. Eventually the EU2 was shut down in January 2015. An anomaly investigation was chartered to determine root cause of the power fluctuations and other anomalous observations. A team with members from Glenn, Sunpower, and LM conducted a thorough investigation of the EU2 anomalies. Findings from the EU2 disassembly identified proximate causes of the anomalous observations. Discussion of the team's assessment of the primary possible failure theories, root cause, and conclusions is provided. Recommendations are made for future Stirling generator development to address the findings from the anomaly investigation. Additional findings from the investigation are also discussed.

Generation risk assessment in volatile conditions with wind, hydro, and natural gas units

International Nuclear Information System (INIS)

Sahin, Cem; Shahidehpour, Mohammad; Erkmen, Ismet

2012-01-01

Highlights: ► Stochastic price-based unit commitment (PBUC) for a generation company (GENCO). ► Water inflow, wind, and NG interruption uncertainties are considered. ► Diversification of assets and bilateral contracts enhance payoff and decrease financial risk. ► The utilization of NG in the risk-neutral GENCO case increases as the wind uncertainty increases. ► NG utilization is lowered by the algorithm to decrease in risk-considered case. -- Abstract: This paper studies a generating company (GENCO)’s midterm (a few months to a year) scheduling payoffs and risks in volatile operating conditions. The proposed algorithm considers the integration of intermittent wind units into a GENCO’s generation assets and coordinates the GENCO’s hourly wind generation schedule with that of natural gas (NG) units (with volatile gas prices) and hydro units (with water inflow forecast) for maximizing the GENCO’s payoff. The proposed midterm GENCO model applies market price forecasts to the risk-constrained stochastic price-based unit commitment (PBUC) for calculating the GENCO’s risk in energy and ancillary services markets. The proposed PBUC minimizes the cost of (a) NG contracts, storage, startup and shutdown, (b) startup and shutdown of cascaded hydro units, and (c) penalty for defaulting on the scheduled power delivery. Simulation results show that the diversification of generating assets including bilateral contracts (BCs) could enhance the GENCO’s midterm planning by increasing the expected payoff and decreasing the financial risk.

Highly Flexible and Washable Nonwoven Photothermal Cloth for Efficient and Practical Solar Steam Generation

KAUST Repository

Jin, Yong

2018-03-29

Solar-driven water evaporation is emerging as a promising solar-energy utilization process. In the present work, highly stable, flexible and washable nonwoven photothermal cloth is prepared by electrospinning for efficient and durable solar steam evaporation. The cloth is composed of polymeric nanofibers as matrix and inorganic carbon black nanoparticles encapsulated inside the matrix as light absorbing component. The photothermal cloth with an optimized carbon loading shows a desirable underwater black property, absorbing 94% of the solar spectrum and giving rise to a state-of-the-art solar energy utilization efficiency of 83% during pure water evaporation process. Owing to its compositions and special structural design, the cloth possesses anti-photothermal-component-loss property and is highly flexible and mechanically strong, chemically stable in various harsh environment such as strong acid, alkaline, organic solvent and salty water. It can be hand-washed for more than 100 times without degrading its performance and thus offers a potential mechanism for foulant cleaning during practical solar steam generation and distillation processes. The results of this work stimulate more research in durable photothermal materials aiming at real world applications.

A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

International Nuclear Information System (INIS)

Yoon, Sunghyun; Cho, Young-Ho

2014-01-01

We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2∼1.0μW in the Human heart rate range on the skin contact area of 3.71cm 2 . Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves

Incentivizing Flexibility in System Operations

Energy Technology Data Exchange (ETDEWEB)

Milligan, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bloom, Aaron P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Townsend, Aaron [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ela, Erik [Electric Power Research Institute; Botterud, Audun [Argonne National Laboratory; Levin, Todd [Argonne National Laboratory

2018-02-15

Defining flexibility has been a challenge that a number of industry members and researchers have attempted to address in recent years. With increased variability and uncertainty of variable generation (VG), the resources on the system will have to be more flexible to adjust output, so that power output ranges, power ramp rates, and energy duration sustainability are sufficient to meet the needs of balancing supply with demand at various operational timescales. This chapter discusses whether existing market designs provide adequate incentives for resources to offer their flexibility into the market to meet the increased levels of variability and uncertainty introduced by VG in the short-term operational time frame. It presents a definition of flexibility and discusses how increased levels of VG require increased needs for flexibility on power systems. Following this introductory material, the chapter examines how existing market designs ensure that resources have the right incentives to provide increased flexibility, and then discusses a number of emerging market design elements that impact flexibility incentives.

Some problems raised by the operation of large nuclear turbo-generator sets. Automatic control system for steam turbo-generator units

International Nuclear Information System (INIS)

Cecconi, F.

1976-01-01

The design of an appropriate automatic system was found to be useful to improve the control of large size turbo-generator units so as to provide easy and efficient control and monitoring. The experience of the manufacturer of these turbo-generator units allowed a system well suited for this function to be designed [fr

Salem Nuclear Generating Station, Unit 1. Annual operating report for 1976

International Nuclear Information System (INIS)

1977-01-01

Initial reactor criticality was achieved 12/11/76 and power generation began 12/25/76. Information is presented concerning operation, maintenance, procedure and specification changes, power generation, unit shutdowns and forced power reductions, testing, and personnel radiation exposures

House of Generations

DEFF Research Database (Denmark)

Geert Jensen, Birgitte

2017-01-01

only the benefits of living close to the family. The Aarhus Municipality project "House of Generations" is a vision for creating a framework for relationships across all generations, for meaningful encounters and for rewarding neighbourliness. Three of Aarhus Municipality's magistrate departments...... participate in the project: Health and Care, Children and Youth, and Social Conditions and Employment. A public housing association that provides student dorms also participates in the project. The physical framework will be a building with a total area of approx. 25,000 m², located at Pier 4, at Aarhus......' harbour areas. The building will be a multi-generational house comprising a mixture of flexible public housing units for students, the elderly and residents who require care (elderly disabled people and people with acquired brain injuries). The building will be connected with common areas located in close...

Comparison of the heat generation of light curing units.

Science.gov (United States)

Bagis, Bora; Bagis, Yildirim; Ertas, Ertan; Ustaomer, Seda

2008-02-01

The aim of this study was to evaluate the heat generation of three different types of light curing units. Temperature increases were recorded from a distance of 1 mm from a thermocouple to the tip of three different types of light curing units including one quartz-tungsten halogen (QTH), one plasma arc (PAC), and one light emitting diode (LED) unit. An experimental model was designed to fix the 1 mm distance between the tip of the light curing units and the thermocouple wire. Temperature changes were recorded in 10 second intervals up to 40 seconds. (10, 20, 30, and 40 seconds). Temperature measurements were repeated three times for every light curing unit after a one hour standby period. Statistical analysis of the results was performed using the analysis of variance (ANOVA) and the Bonferroni Test. The highest temperature rises (54.4+/-1.65 degrees C) occurred during activation of a PAC light curing unit for every test period (pdamage to the pulp.

Market Designs for High Levels of Variable Generation: Preprint

Energy Technology Data Exchange (ETDEWEB)

Milligan, M.; Holttinen, H.; Kiviluoma, J.; Orths, A.; Lynch, M.; Soder, L.

2014-10-01

Variable renewable generation is increasing in penetration in modern power systems, leading to higher variability in the supply and price of electricity as well as lower average spot prices. This raises new challenges, particularly in ensuring sufficient capacity and flexibility from conventional technologies. Because the fixed costs and lifetimes of electricity generation investments are significant, designing markets and regulations that ensure the efficient integration of renewable generation is a significant challenge. This papers reviews the state of play of market designs for high levels of variable generation in the United States and Europe and considers new developments in both regions.

Steam generator tube integrity requirements and operating experience in the United States

International Nuclear Information System (INIS)

Karwoski, K.J.

2009-01-01

Steam generator tube integrity is important to the safe operation of pressurized-water reactors. For ensuring tube integrity, the U.S. Nuclear Regulatory Commission uses a regulatory framework that is largely performance based. This performance-based framework is supplemented with some prescriptive requirements. The framework recognizes that there are three combinations of tube materials and heat treatments currently used in the United States and that the operating experience depends, in part, on the type of material used. This paper summarizes the regulatory framework for ensuring steam generator tube integrity, it highlights the current status of steam generators, and it highlights some of the steam generator issues and challenges that exist in the United States. (author)

Harnessing Flexibility from Hot and Cold

DEFF Research Database (Denmark)

Kiviluoma, Juha; Heinen, Steve; Qazi, Hassan

2017-01-01

As has been often reported, electricity systems with high levels of variable wind and solar power generation would benefit from demand flexibility. What is not as often mentioned is that electrification of the transport and heat sectors could exacerbate the need for flexibility, if they are imple...

Distributed generation investment by a microgrid under uncertainty

International Nuclear Information System (INIS)

Siddiqui, Afzal S.; Marnay, Chris

2008-01-01

This paper examines a California-based microgrid's decision to invest in a distributed generation (DG) unit fuelled by natural gas. While the long-term natural gas generation cost is stochastic, we initially assume that the microgrid may purchase electricity at a fixed retail rate from its utility. Using the real options approach, we find a natural gas generation cost threshold that triggers DG investment. Furthermore, the consideration of operational flexibility by the microgrid increases DG investment, while the option to disconnect from the utility is not attractive. By allowing the electricity price to be stochastic, we next determine an investment threshold boundary and find that high electricity price volatility relative to that of natural gas generation cost delays investment while simultaneously increasing the value of the investment. We conclude by using this result to find the implicit option value of the DG unit when two sources of uncertainty exist. (author)

Distributed Generation Investment by a Microgrid under Uncertainty

Energy Technology Data Exchange (ETDEWEB)

Marnay, Chris; Siddiqui, Afzal; Marnay, Chris

2008-08-11

This paper examines a California-based microgrid?s decision to invest in a distributed generation (DG) unit fuelled by natural gas. While the long-term natural gas generation cost is stochastic, we initially assume that the microgrid may purchase electricity at a fixed retail rate from its utility. Using the real options approach, we find a natural gas generation cost threshold that triggers DG investment. Furthermore, the consideration of operational flexibility by the microgrid increases DG investment, while the option to disconnect from the utility is not attractive. By allowing the electricity price to be stochastic, we next determine an investment threshold boundary and find that high electricity price volatility relative to that of natural gas generation cost delays investment while simultaneously increasing the value of the investment. We conclude by using this result to find the implicit option value of the DG unit when two sources of uncertainty exist.

The technology of the bearings used in the nuclear power generation system turbine generator units

International Nuclear Information System (INIS)

Vialettes, J.M.; Rossato, M.

1997-01-01

A bearing consists of all the stationary part which allow the relative motion in rotation or in translation, of a shaft line. Inside the bearing there is a journal bearing with a metallic anti-friction coating (the babbitt metal). The high power turbine generator unit rotors are supported by smooth transversal journal bearings fed with oil which fills the empty space and runs along the shaft. The technologies used for the bearings and the thrust bearings of the turbine generator units and the various shaft lines of the French CP0/CP1- and CP2/1300 MW-type nuclear power plants are described. The experience feedback is then discussed in terms of the dynamics of the shaft line, i.e. vibrational problems, the influence of the alignment and the babbitt metal incidents. (author)

Needs for Flexibility Caused by the Variability and Uncertainty in Wind and Solar Generation in 2020, 2030 and 2050 Scenarios

DEFF Research Database (Denmark)

Koivisto, Matti Juhani; Sørensen, Poul Ejnar; Maule, Petr

The growing share of variable renewable energy sources (VRE) in Nordic and Baltic countries is expected to increase the need for flexibility in the energy systems. VRE generation is highly variable because it is determined by weather conditions, and it is uncertain due to forecasting errors. Both...

Selectively Plasmon-Enhanced Second-Harmonic Generation from Monolayer Tungsten Diselenide on Flexible Substrates

KAUST Repository

Wang, Zhuo

2018-01-04

Monolayer two-dimensional transition metal dichalcogenides (2D TMDCs) exhibit promising characteristics in miniaturized nonlinear optical frequency converters, due to their inversion asymmetry and large second-order nonlinear susceptibility. However, these materials usually have a very short light interaction lengths with the pump laser because they are atomically thin, such that second-harmonic generation (SHG) is generally inefficient. In this paper, we fabricate a judiciously structured 150-nm-thick planar surface consisting of monolayer tungsten diselenide and sub-20-nm-wide gold trenches on flexible substrates, reporting ~7000-fold SHG enhancement without peak broadening or background in the spectra as compared to WSe2 on as-grown sapphire substrates. Our proof-of-concept experiment yields effective second-order nonlinear susceptibility of 2.1 × 104 pm/V. Three orders of magnitude enhancement is maintained with pump wavelength ranging from 800 nm to 900 nm, breaking the limitation of narrow pump wavelength range for cavity-enhanced SHG. In addition, SHG amplitude can be dynamically controlled via selective excitation of the lateral gap plasmon by rotating the laser polarization. Such fully open, flat and ultrathin profile enables a great variety of functional samples with high SHG from one patterned silicon substrate, favoring scalable production of nonlinear converters. The surface accessibility also enables integration with other optical components for information processing in an ultrathin and flexible form.

Selectively Plasmon-Enhanced Second-Harmonic Generation from Monolayer Tungsten Diselenide on Flexible Substrates

KAUST Repository

Wang, Zhuo; Dong, Zhaogang; Zhu, Hai; Jin, Lei; Chiu, Ming-Hui; Li, Lain-Jong; Xu, Qing-Hua; Eda, Goki; Maier, Stefan A.; Wee, Andrew T. S.; Qiu, Cheng-Wei; Yang, Joel K.W.

2018-01-01

Monolayer two-dimensional transition metal dichalcogenides (2D TMDCs) exhibit promising characteristics in miniaturized nonlinear optical frequency converters, due to their inversion asymmetry and large second-order nonlinear susceptibility. However, these materials usually have a very short light interaction lengths with the pump laser because they are atomically thin, such that second-harmonic generation (SHG) is generally inefficient. In this paper, we fabricate a judiciously structured 150-nm-thick planar surface consisting of monolayer tungsten diselenide and sub-20-nm-wide gold trenches on flexible substrates, reporting ~7000-fold SHG enhancement without peak broadening or background in the spectra as compared to WSe2 on as-grown sapphire substrates. Our proof-of-concept experiment yields effective second-order nonlinear susceptibility of 2.1 × 104 pm/V. Three orders of magnitude enhancement is maintained with pump wavelength ranging from 800 nm to 900 nm, breaking the limitation of narrow pump wavelength range for cavity-enhanced SHG. In addition, SHG amplitude can be dynamically controlled via selective excitation of the lateral gap plasmon by rotating the laser polarization. Such fully open, flat and ultrathin profile enables a great variety of functional samples with high SHG from one patterned silicon substrate, favoring scalable production of nonlinear converters. The surface accessibility also enables integration with other optical components for information processing in an ultrathin and flexible form.

Generational attitudes of rural mental health nurses.

Science.gov (United States)

Crowther, Andrew; Kemp, Michael

2009-04-01

To determine how attitudes of rural mental health nurses differ across generations. Survey. Mental health services in rural New South Wales. Practising mental health nurses. Survey responses. Survey response rate 44%. A total of 89 mental health nurses, clustered in inpatient units and community health centres, responded. Of these nurses, 4 were veterans, 52 baby boomers, 17 Generation X and 5 Generation Y. There are significant differences in how mental health nurses from different generations view their work, and in what is expected from managers. Managers need to modify traditional working styles, allowing greater flexibility of employment. They must also accept lower staff retention rates, and facilitate the development of younger staff.

Flexible transparent electrode

Science.gov (United States)

Demiryont, Hulya; Shannon, Kenneth C., III; Moorehead, David; Bratcher, Matthew

2011-06-01

This paper presents the properties of the EclipseTECTM transparent conductor. EclipseTECTM is a room temperature deposited nanostructured thin film coating system comprised of metal-oxide semiconductor elements. The system possesses metal-like conductivity and glass-like transparency in the visible region. These highly conductive TEC films exhibit high shielding efficiency (35dB at 1 to 100GHz). EclipseTECTM can be deposited on rigid or flexible substrates. For example, EclipseTECTM deposited on polyethylene terephthalate (PET) is extremely flexible that can be rolled around a 9mm diameter cylinder with little or no reduction in electrical conductivity and that can assume pre-extension states after an applied stress is relieved. The TEC is colorless and has been tailored to have high visible transmittance which matches the eye sensitivity curve and allows the viewing of true background colors through the coating. EclipseTECTM is flexible, durable and can be tailored at the interface for applications such as electron- or hole-injecting OLED electrodes as well as electrodes in flexible displays. Tunable work function and optical design flexibility also make EclipseTECTM well-suited as a candidate for grid electrode replacement in next-generation photovoltaic cells.

Evolving Distributed Generation Support Mechanisms: Case Studies from United States, Germany, United Kingdom, and Australia

Energy Technology Data Exchange (ETDEWEB)

Lowder, Travis [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zhou, Ella [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tian, Tian [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2017-03-14

This report expands on a previous National Renewable Energy Laboratory (NREL) technical report (Lowder et al. 2015) that focused on the United States' unique approach to distributed generation photovoltaics (DGPV) support policies and business models. While the focus of that report was largely historical (i.e., detailing the policies and market developments that led to the growth of DGPV in the United States), this report looks forward, narrating recent changes to laws and regulations as well as the ongoing dialogues over how to incorporate distributed generation (DG) resources onto the electric grid. This report also broadens the scope of Lowder et al. (2015) to include additional countries and technologies. DGPV and storage are the principal technologies under consideration (owing to market readiness and deployment volumes), but the report also contemplates any generation resource that is (1) on the customer side of the meter, (2) used to, at least partly, offset a host's energy consumption, and/or (3) potentially available to provide grid support (e.g., through peak shaving and load shifting, ancillary services, and other means).

Power System Integration of Flexible Demand in the Low Voltage Network

DEFF Research Database (Denmark)

Thavlov, Anders

, it is natural to consider electricity consumption from households as an integrated part of a potential flexible demand side in the future power system. However, as an individual unit a single household is not able to generate a large impact in the power system. Therefore, a mechanism is needed which can...... is even greater as almost 50% of the electricity consumption in households is utilised for space heating and cooling and for heating of domestic hot water. Consequently, there exists a significant potential in the integration of power consumption for heating purposes in households for demand response...... of electricity on the Nordic energy exchange, Nord Pool, or alternatively the flexibility can be sold as an ancillary service to the transmission system operator. In this way, the electricity consumption in households are indirectly integrated into the power market, through the virtual power plant...

Design of flexible polyphenylene proton-conducting membrane for next-generation fuel cells.

Science.gov (United States)

Miyake, Junpei; Taki, Ryunosuke; Mochizuki, Takashi; Shimizu, Ryo; Akiyama, Ryo; Uchida, Makoto; Miyatake, Kenji

2017-10-01

Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in automotive, stationary, and portable applications. Perfluorosulfonic acid (PFSA) ionomers (for example, Nafion) have been the benchmark PEMs; however, several problems, including high gas permeability, low thermal stability, high production cost, and environmental incompatibility, limit the widespread dissemination of PEMFCs. It is believed that fluorine-free PEMs can potentially address all of these issues; however, none of these membranes have simultaneously met the criteria for both high performance (for example, proton conductivity) and durability (for example, mechanical and chemical stability). We present a polyphenylene-based PEM (SPP-QP) that fulfills the required properties for fuel cell applications. The newly designed PEM exhibits very high proton conductivity, excellent membrane flexibility, low gas permeability, and extremely high stability, with negligible degradation even under accelerated degradation conditions, which has never been achieved with existing fluorine-free PEMs. The polyphenylene PEM also exhibits reasonably high fuel cell performance, with excellent durability under practical conditions. This new PEM extends the limits of existing fluorine-free proton-conductive materials and will help to realize the next generation of PEMFCs via cost reduction as well as the performance improvement compared to the present PFSA-based PEMFC systems.

ASP - Grid connections of large power generating units; ASP - Anslutning av stoerre produktionsanlaeggningar till elnaetet

Energy Technology Data Exchange (ETDEWEB)

Larsson, Aake; Larsson, Richard [Vattenfall Power Consultants, Stockholm (Sweden)

2006-12-15

Grid connections of large power generating units normally require more detailed studies compared to small single units. The required R and D-level depends on the specific characteristics of the production units and the connecting grid. An inquiry for a grid connection will raise questions for the grid owner regarding transmission capability, losses, fault currents, relay protection, dynamic stability etc. Then only a few larger wind farms have been built, the experiences from these types of grid connections are limited and for that reason it can be difficult to identify issues appropriate for further studies. To ensure that electric power generating units do not have unacceptable impact on the grid, directions from the Swedish TSO (Svenska Kraftnaet) have been stated. The directions deal, for example, with power generation in specific ranges of voltage level and frequency and the possibility to remain connected to the grid when different faults occur. The requirements and the consequences of these directions are illustrated. There are three main issues that should be considered: Influence on the power flow from generating units regarding voltage level, currents, losses etc.; Different types of electric systems in generating units contribute to different levels of fault currents. For that reason the resulting fault current levels have to be studied; It is required that generating units should remain connected to the grid at different modes of operation and faults. These modes have to be verified. Load flow and dynamic studies normally demand computer models. Comprehensive models, for instance of wind farms, can bee difficult to design and normally large computer capacity is required. Therefore simplified methods to perform relevant studies are described. How to model an electric power generating unit regarding fault currents and dynamic stability is described. An inquiry for a grid connection normally brings about a discussion concerning administration. To make it

Demand flexibility from residential heat pump

DEFF Research Database (Denmark)

Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

2014-01-01

Demand response (DR) is considered as a potentially effective tool to compensate generation intermittency imposed by renewable sources. Further, DR can instigate to offer optimum asset utilization and to avoid or delay the need for new infrastructure investment. Being a sizable load together...... with high thermal time constant, heat pumps (HP) can offer a great deal of flexibility in the future intelligent grids especially to compensate fluctuating generation. However, the HP flexibility is highly dependent on thermal demand profile, namely hot water and space heating demand. This paper proposes...... price based scheduling followed by a demand dispatch based central control and a local voltage based adaptive control, to realize HP demand flexibility. Two-step control architecture, namely local primary control encompassed by the central coordinative control, is proposed to implement...

A cross-cultural comparison of children's imitative flexibility.

Science.gov (United States)

Clegg, Jennifer M; Legare, Cristine H

2016-09-01

Recent research with Western populations has demonstrated that children use imitation flexibly to engage in both instrumental and conventional learning. Evidence for children's imitative flexibility in non-Western populations is limited, however, and has only assessed imitation of instrumental tasks. This study (N = 142, 6- to 8-year-olds) demonstrates both cultural continuity and cultural variation in imitative flexibility. Children engage in higher imitative fidelity for conventional tasks than for instrumental tasks in both an industrialized, Western culture (United States), and a subsistence-based, non-Western culture (Vanuatu). Children in Vanuatu engage in higher imitative fidelity of instrumental tasks than in the United States, a potential consequence of cultural variation in child socialization for conformity. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Economical and ecological benchmarking of biogas plant configurations for flexible power generation in future power supply systems; Oekonomisches und oekologisches Benchmarking von Biogasanlagenkonfigurationen zur flexiblen Verstromung in zukuenftigen Stromversorgungssystemen

Energy Technology Data Exchange (ETDEWEB)

Hahn, Henning [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany). Bereich Energieverfahrenstechnik

2016-08-01

With the share of intermittent renewable energies within the electricity system rising, balancing services from dispatchable power plants are of increasing importance. This study comparatively assesses the environmental and economic performance of biogas plant configurations, supplying biogas on demand for flexible power generation. A cost analysis of five configurations based on biogas storing and flexible biogas production concepts has been carried out. Results show that additional flexibility costs for a biogas supply of 8 hours per day range between 2 Euro to 11 Euro MWh{sup -1} and for a 72 hour period without biogas demand from 9 Euro to 19 Euro MWh{sup -1}. While biogas storage concepts were identified as favorable short-term supply configurations, flexible biogas production concepts profit from reduced storage requirements at plants with large biogas production capacities or for longer periods without biogas demand [1, 2]. Flexible biogas plant configurations indicate an increased energy demand to operate the operational enhancements compared to conventional biogas plants supplying biogas for baseload power generation. However, findings show that in contrast to an alternative supply of power generators with natural gas, biogas supplied on demand by adapted biogas plant configurations saves greenhouse gas emissions by 54 to 65 g CO{sub 2-eq} MJ{sup -1} and primary energy by about 1.17 MJ MJ{sup -1}. In this regard, configurations with flexible biogas production profit from reduced biogas storage requirements and achieve higher savings compared to configurations with continuous biogas production [1, 3].

Distributed generation investment by a microgrid under uncertainty

Energy Technology Data Exchange (ETDEWEB)

Siddiqui, Afzal S. [Department of Statistical Science, University College London, Gower Street, London WC1E 6BT (United Kingdom); Marnay, Chris [Ernest Orlando Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS90R4000, Berkeley, CA 94720-8163 (United States)

2008-12-15

This paper examines a California-based microgrid's decision to invest in a distributed generation (DG) unit fuelled by natural gas. While the long-term natural gas generation cost is stochastic, we initially assume that the microgrid may purchase electricity at a fixed retail rate from its utility. Using the real options approach, we find a natural gas generation cost threshold that triggers DG investment. Furthermore, the consideration of operational flexibility by the microgrid increases DG investment, while the option to disconnect from the utility is not attractive. By allowing the electricity price to be stochastic, we next determine an investment threshold boundary and find that high electricity price volatility relative to that of natural gas generation cost delays investment while simultaneously increasing the value of the investment. We conclude by using this result to find the implicit option value of the DG unit when two sources of uncertainty exist. (author)

Some problems raised by the operation of large nuclear turbo-generator sets. Solutions proposed for the protection of large size generators

International Nuclear Information System (INIS)

Chaumienne, J.-P.

1976-01-01

The operating requirements of nuclear power stations call for relays with ever increasing performances. This urges the development of new electronic systems while giving high importance to their reliability. So as to provide for easy application and minitoring of the relays, even when the turbo-generator unit is operating, a new cubicle design is considered which offers maximum safety and flexibility in use [fr

Flexible Generation of Pervasive Web Services using OSGi Declarative Services and OWL Ontologies

DEFF Research Database (Denmark)

Hansen, Klaus Marius; Zhang, Weishan; Fernandes, Joao

2008-01-01

There is a growing trend to deploy web services in pervasive computing environments. Implementing web services on networked, embedded devices leads to a set of challenges, including productivity of development, efficiency of web services, and handling of variability and dependencies of hardware...... and software platforms. To address these challenges, we developed a web service compiler called Limbo, in which Web Ontology Language (OWL) ontologies are used to make the Limbo compiler aware of its compilation context such as device hardware and software details, platform dependencies, and resource....../power consumption. The ontologies are used to configure Limbo for generating resource-efficient web service code. The architecture of Limbo follows the Blackboard architectural style and Limbo is implemented using the OSGi Declarative Services component model. The component model provides high flexibility...

Flexible Field Emitter for X-ray Generation by Implanting CNTs into Nickel Foil

Science.gov (United States)

Sun, Bin; Wang, Yan; Ding, Guifu

2016-09-01

This paper reports on a flexible Ni micro wire with CNTs embedded into its surface. By using micromachining technology, for the first time, we could implant nanoscale materials into micro-scale metal substrate at room temperature. Thanks to the effective direct contact and the strong interactions between CNTs and the substrate, field emission current of 1.11 mA (current density of 22.2 mA/cm2) could be achieved from the micro wire. Moreover, the wire shows excellent mechanical properties for large amplitude bending, which is beneficial for geometric designing. To check the practical application of the wire, a simplified X-ray imaging system was set up by modifying a conventional tube. The gray shade that appears on the sensitive film after being exposed to the radiation confirms the X-ray generation.

Developmental constraints on behavioural flexibility.

Science.gov (United States)

Holekamp, Kay E; Swanson, Eli M; Van Meter, Page E

2013-05-19

We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

Flexible Power Control of Photovoltaic Systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Sangwongwanich, Ariya; Yang, Yongheng

2018-01-01

With a still increasing penetration level of grid-connected photovoltaic (PV) systems, more advanced and flexible control functionalities are demanded. To ensure a smooth and friendly integration between the PV systems and the grid, the power generated by the PV system needs to be flexible...

Flexible and elastic metamaterial absorber for low frequency, based on small-size unit cell

Energy Technology Data Exchange (ETDEWEB)

Yoo, Y. J.; Zheng, H. Y.; Kim, Y. J.; Lee, Y. P., E-mail: yplee@hanyang.ac.kr [Department of Physics and RINS, Hanyang University, Seoul 133-791 (Korea, Republic of); Rhee, J. Y. [Department of Physics, Sungkyunkwan University, Suwon (Korea, Republic of); Kang, J.-H. [Department of Nano and Electronic Physics, Kookmin University, Seoul (Korea, Republic of); Kim, K. W. [Department of Information Display, Sunmoon University, Asan (Korea, Republic of); Cheong, H. [Department of Physics, Sogang University, Seoul (Korea, Republic of); Kim, Y. H. [Infovion Inc., Seoul (Korea, Republic of)

2014-07-28

Using a planar and flexible metamaterial (MM), we obtained the low-frequency perfect absorption even with very small unit-cell size in snake-shape structure. These shrunken, deep-sub-wavelength and thin MM absorbers were numerically and experimentally investigated by increasing the inductance. The periodicity/thickness (the figure of merit for perfect absorption) is achieved to be 10 and 2 for single-snake-bar and 5-snake-bar structures, respectively. The ratio between periodicity and resonance wavelength (in mm) is close to 1/12 and 1/30 at 2 GHz and 400 MHz, respectively. The absorbers are specially designed for absorption peaks around 2 GHz and 400 MHz, which can be used for depressing the electromagnetic noise from everyday electronic devices and mobile phones.

Convergence of pattern generator outputs on a common mechanism of diaphragm motor unit recruitment.

Science.gov (United States)

Mantilla, Carlos B; Seven, Yasin B; Sieck, Gary C

2014-01-01

Motor units are the final element of neuromotor control. In manner analogous to the organization of neuromotor control in other skeletal muscles, diaphragm motor units comprise phrenic motoneurons located in the cervical spinal cord that innervate the diaphragm muscle, the main inspiratory muscle in mammals. Diaphragm motor units play a primary role in sustaining ventilation but are also active in other nonventilatory behaviors, including coughing, sneezing, vomiting, defecation, and parturition. Diaphragm muscle fibers comprise all fiber types. Thus, diaphragm motor units display substantial differences in contractile and fatigue properties, but importantly, properties of the motoneuron and muscle fibers within a motor unit are matched. As in other skeletal muscles, diaphragm motor units are recruited in order such that motor units that display greater fatigue resistance are recruited earlier and more often than more fatigable motor units. The properties of the motor unit population are critical determinants of the function of a skeletal muscle across the range of possible motor tasks. Accordingly, fatigue-resistant motor units are sufficient to generate the forces necessary for ventilatory behaviors, whereas more fatigable units are only activated during expulsive behaviors important for airway clearance. Neuromotor control of diaphragm motor units may reflect selective inputs from distinct pattern generators distributed according to the motor unit properties necessary to accomplish these different motor tasks. In contrast, widely distributed inputs to phrenic motoneurons from various pattern generators (e.g., for breathing, coughing, or vocalization) would dictate recruitment order based on intrinsic electrophysiological properties. © 2014 Elsevier B.V. All rights reserved.

Innovation of blow-down system in steam generators of a VVER 440 unit

International Nuclear Information System (INIS)

Matal, O.; Simo, T.; Mancev, M.D.

1997-01-01

The impurities getting into the steam generator with the feedwater are continually removed by the blowdown and unit sludge system. The mostly non-symmetrical type of pipe branches under steam generators at WWER-440 units causes nonuniform blowdown flow rates at the halves of the steam generator; this often leads to a blocking of the pipe with the lower flow rate. The most simple way of hydraulically equalizing the blowdown pipes is to implement symmetric blowdown pipes and to install efficient throttling elements in the pipe. The proposed innovation will make it possible to re-distribute the blowdown flow rates and to reduce more effectively the concentrations of impurities in steam generators. (M.D.)

Towards constraint-based aggregation of energy flexibilities

DEFF Research Database (Denmark)

Valsomatzis, Emmanouil; Pedersen, Torben Bach; Abello, Alberto

2016-01-01

present the problem of aggregating energy flexibilities taking into account grid capacity limitations and introduce a heuristic aggregation technique. We show through an experimental setup that our proposed technique, compared to a baseline approach, not only leads to a valid unit commitment result......The aggregation of energy flexibilities enables individual producers and/or consumers with small loads to directly participate in the emerging energy markets. On the other hand, aggregation of such flexibilities might also create problems to the operation of the electrical grid. In this paper, we...

Coal-Powered Electric Generating Unit Efficiency and Reliability Dialogue: Summary Report

Energy Technology Data Exchange (ETDEWEB)

Taylor, Emmanuel [Energetics, Inc., Columbia, MD (United States)

2018-02-01

Coal continues to play a critical role in powering the Nation’s electricity generation, especially for baseload power plants. With aging coal generation assets facing decreased performance due to the state of the equipment, and with challenges exacerbated by the current market pressures on the coal sector, there are opportunities to advance early-stage technologies that can retrofit or replace equipment components. These changes will eventually result in significant improvements in plant performance once further developed and deployed by industry. Research and development in areas such as materials, fluid dynamics, fuel properties and preparation characteristics, and a new generation of plant controls can lead to new components and systems that can help improve the efficiency and reliability of coal-fired power plants significantly, allowing these assets to continue to provide baseload power. Coal stockpiles at electricity generation plants are typically large enough to provide 30 to 60 days of power prior to resupply—significantly enhancing the stability and reliability of the U.S. electricity sector. Falling prices for non-dispatchable renewable energy and mounting environmental regulations, among other factors, have stimulated efforts to improve the efficiency of these coal-fired electric generating units (EGUs). In addition, increased reliance on natural gas and non-dispatchable energy sources has spurred efforts to further increase the reliability of coal EGUs. The Coal Powered EGU Efficiency and Reliability Dialogue brought together stakeholders from across the coal EGU industry to discuss methods for improvement. Participants at the event reviewed performance-enhancing innovations in coal EGUs, discussed the potential for data-driven management practices to increase efficiency and reliability, investigated the impacts of regulatory compliance on coal EGU performance, and discussed upcoming challenges for the coal industry. This report documents the key

75 FR 6223 - PSEG Nuclear LLC; Hope Creek Generating Station and Salem Nuclear Generating Station, Unit Nos. 1...

Science.gov (United States)

2010-02-08

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-272, 50-311 and 50-354; NRC-2010-0043] PSEG Nuclear LLC; Hope Creek Generating Station and Salem Nuclear Generating Station, Unit Nos. 1 and 2...-70, and DPR-75, issued to PSEG Nuclear LLC (PSEG, the licensee), for operation of the Hope Creek...

Flexible Transmission Network Expansion Planning Considering Uncertain Renewable Generation and Load Demand Based on Hybrid Clustering Analysis

Directory of Open Access Journals (Sweden)

Yun-Hao Li

2015-12-01

Full Text Available This paper presents a flexible transmission network expansion planning (TNEP approach considering uncertainty. A novel hybrid clustering technique, which integrates the graph partitioning method and rough fuzzy clustering, is proposed to cope with uncertain renewable generation and load demand. The proposed clustering method is capable of recognizing the actual cluster distribution of complex datasets and providing high-quality clustering results. By clustering the hourly data for renewable generation and load demand, a multi-scenario model is proposed to consider the corresponding uncertainties in TNEP. Furthermore, due to the peak distribution characteristics of renewable generation and heavy investment in transmission, the traditional TNEP, which caters to rated renewable power output, is usually uneconomic. To improve the economic efficiency, the multi-objective optimization is incorporated into the multi-scenario TNEP model, while the curtailment of renewable generation is considered as one of the optimization objectives. The solution framework applies a modified NSGA-II algorithm to obtain a set of Pareto optimal planning schemes with different levels of investment costs and renewable generation curtailments. Numerical results on the IEEE RTS-24 system demonstrated the robustness and effectiveness of the proposed approach.

Flexible strategy for immobilizing redox-active compounds using in situ generation of diazonium salts. Investigations of the blocking and catalytic properties of the layers.

Science.gov (United States)

Noël, Jean-Marc; Sjöberg, Béatrice; Marsac, Rémi; Zigah, Dodzi; Bergamini, Jean-François; Wang, Aifang; Rigaut, Stéphane; Hapiot, Philippe; Lagrost, Corinne

2009-11-03

A versatile two-step method is developed to covalently immobilize redox-active molecules onto carbon surfaces. First, a robust anchoring platform is grafted onto surfaces by electrochemical reduction of aryl diazonium salts in situ generated. Depending on the nature of the layer termini, -COOH or -NH(2), a further chemical coupling involving ferrocenemethylamine or ferrocene carboxylic acid derivatives leads to the covalent binding of ferrocene centers. The chemical strategy using acyl chloride activation is efficient and flexible, since it can be applied either to surface-reactive end groups or to reactive species in solution. Cyclic voltammetry analyses point to the covalent binding of ferrocene units restricted to the upper layers of the underlying aryl films, while AFM measurements show a lost of compactness of the layers after the chemical attachment of ferrocene centers. The preparation conditions of the anchoring layers were found to determine the interfacial properties of the resulted ferrocenyl-modified electrodes. The ferrocene units promoted effective redox mediation providing that the free redox probes are adequately chosen (i.e., vs size/formal potential) and the underlying layers exhibit strong blocking properties. For anchoring films with weaker blocking effect, the coexistence of two distinct phenomena, redox mediation and ET at pinholes could be evidenced.

High-Performance Pseudo-Random Number Generation on Graphics Processing Units

OpenAIRE

Nandapalan, Nimalan; Brent, Richard P.; Murray, Lawrence M.; Rendell, Alistair

2011-01-01

This work considers the deployment of pseudo-random number generators (PRNGs) on graphics processing units (GPUs), developing an approach based on the xorgens generator to rapidly produce pseudo-random numbers of high statistical quality. The chosen algorithm has configurable state size and period, making it ideal for tuning to the GPU architecture. We present a comparison of both speed and statistical quality with other common parallel, GPU-based PRNGs, demonstrating favourable performance o...

Flexible voltage support control for three-phase distributed generation inverters under grid fault

DEFF Research Database (Denmark)

Camacho, Antonio; Castilla, Miguel; Miret, Jaume

2013-01-01

Operators describe the behavior of the energy source, regulating voltage limits and reactive power injection to remain connected and support the grid under fault. On the basis that different kinds of voltage sags require different voltage support strategies, a flexible control scheme for three phase grid...... connected inverters is proposed. In three phase balanced voltage sags, the inverter should inject reactive power in order to raise the voltage in all phases. In one or two phase faults, the main concern of the distributed generation inverter is to equalize voltages by reducing the negative symmetric...... sequence and clear the phase jump. Due to system limitations, a balance between these two extreme policies is mandatory. Thus, over-voltage and undervoltage can be avoided, and the proposed control scheme prevents disconnection while achieving the desired voltage support service. The main contribution...

Experience in connecting the power generating units of thermal power plants to automatic secondary frequency regulation within the united power system of Russia

International Nuclear Information System (INIS)

Zhukov, A. V.; Komarov, A. N.; Safronov, A. N.; Barsukov, I. V.

2009-01-01

The principles of central control of the power generating units of thermal power plants by automatic secondary frequency and active power overcurrent regulation systems, and the algorithms for interactions between automatic power control systems for the power production units in thermal power plants and centralized systems for automatic frequency and power regulation, are discussed. The order of switching the power generating units of thermal power plants over to control by a centralized system for automatic frequency and power regulation and by the Central Coordinating System for automatic frequency and power regulation is presented. The results of full-scale system tests of the control of power generating units of the Kirishskaya, Stavropol, and Perm GRES (State Regional Electric Power Plants) by the Central Coordinating System for automatic frequency and power regulation at the United Power System of Russia on September 23-25, 2008, are reported.

Modeling and Control of Low Voltage Flexible Units for Enhanced Operation of Distribution Feeders

DEFF Research Database (Denmark)

Raboni, Pietro; Hu, Weihao; Chaudhary, Sanjay

2013-01-01

In some networks Distributed Generators (DGs) are phasing out conventional power plants in terms of power production but still large efforts are required for providing ancillary services. In this paper the usage of fast response units like a Micro Turbines (MT) and a stationary Electric Vehicle...... Battery (EVB) is proposed for providing primary regulation in grid connected mode and for hierarchically manage an islanded LV distribution feeder. The unit models are described and a novel EVB model directly based on manufacturer’s data is proposed and evaluated comparing its performances with Sim...

Large-Scale Combined Heat and Power (CHP) Generation at Loviisa Nuclear Power Plant Unit 3

International Nuclear Information System (INIS)

Bergroth, N.

2010-01-01

Fortum has applied for a Decision in Principle concerning the construction of a new nuclear power plant unit (Loviisa 3) ranging from 2800-4600 MWth at its site located at the southern coast of Finland. An attractive alternative investigated is a co-generation plant designed for large-scale district heat generation for the Helsinki metropolitan area that is located approximately 75 km west of the site. The starting point is that the district heat generation capacity of 3 unit would be around 1 000 MWth.The possibility of generating district heat for the metropolitan area by Loviisa's two existing nuclear power plant units was investigated back in the 1980s, but it proved unpractical at the time. With the growing concern of the climate change and the subsequent requirements on heat and power generation, the idea is much more attractive today, when recognising its potential to decrease Finland's carbon dioxide emissions significantly. Currently the district heat generation in metropolitan area is based on coal and natural gas, producing some five to seven million tonnes of carbon dioxide emissions annually. Large-scale combined heat and power (CHP) generation at the 3 unit could cut this figure by up to four million tonnes. This would decrease carbon dioxide emissions by as much as six percent. In addition, large-scale CHP generation would increase the overall efficiency of the new unit significantly and hence, reduce the environmental impact on the local marine environment by cutting heat discharges into the Gulf of Nuclear energy has been used for district heating in several countries both in dedicated nuclear heating plants and in CHP generation plants. However, the heat generation capacity is usually rather limited, maximum being around 250 MWth per unit. Set against this, the 3 CHP concept is much more ambitious, not only because of the much larger heat generation output envisaged, but also because the district heating water would have to be transported over a

Contagious flexibility? A study on whether schedule flexibility facilitates work-life enrichment.

Science.gov (United States)

Pedersen, Vivi Bach; Jeppesen, Hans Jeppe

2012-08-01

Schedule flexibility defines an important generating resource for work-life enrichment; however, our knowledge about how such spillovers take place is limited. This multiple case study examines how workers from different working time contexts with varying levels of schedule flexibility experience work-life interplay. Given the adopted explorative design, it is important to interpret the findings in a tentative light. Nonetheless, the study offers important insight into work-life enrichment that may guide future research in this field. The findings indicate that schedule flexibility may act as a boundary-spanning resource owing to the agency potential it offers workers. Thus, it seemed that flexible schedule opportunities enabled workers to engage more fully in personal life activities, which in turn had a positive influence on their work involvement through positive affect. Such positive role engagements appeared, however, to be greatly determined by workers' boundary management and by time conditions of work and family. In conclusion, the major findings and limitation of the study are discussed against existing research and theory. © 2012 The Authors. Scandinavian Journal of Psychology © 2012 The Scandinavian Psychological Associations.

Operating performance of LWR nuclear generating units

International Nuclear Information System (INIS)

Pia, S.

1984-01-01

This work aims at reviewing, on the basis of historical data, the operational problem areas which explain the degree of availability and productivity achieved up to now by nuclear power plants in commercial operation in the world. The operating performance data of nuclear power plants area analysed with respect to plant type, size and other significant reference parameters and they are evaluated also by comparison with fossil generating unit data. Major performance indices data are presented for both nuclear and fossil units type and distribution of outage causes. Unplanned full outages caused by nuclear power plant equipment and components failure are particulary emphasized. The trend for unplanned full outages due to the failure of components shows decreasing numerical values in 1981 with respect to the previous years. But this result should be weighed with the increasing plant unavailability hours needed for maintenance and repair action (chiefly preventive maintenance on critical components). This means that the number and downtime of forced outage must be drastically reduced for economic reasons (production losses and problems associated with the unavailable unit unplanned replacement) as well as for plant safe and reliable operation (sudden unavailability of key components and frequency of transients associated with plant shutdown and routine startup operation)

COTRANSA simulation of Chinshan unit one generator load rejection test

International Nuclear Information System (INIS)

Wu, C.H.

1984-01-01

A simulation of the plant behavior during a BWR generator load rejection transient using Exxon Nuclear Company's COTRANSA code is presented in this paper. The results are compared to measurements obtained by Taiwan Power Company during a generator load rejection transient, initiated at full power condition, which was one of the Chinshan Unit 1 initial cycle startup tests. Good agreement between the COTRANSA predicted and the measured values, indicates that the COTRANSA code can simulate this transient satisfactorily

Wearable Flexible Sensors: A Review

KAUST Repository

Nag, Anindya

2017-05-18

The paper provides a review on some of the significant research work done on wearable flexible sensors (WFS). Sensors fabricated with flexible materials have been attached to a person along with the embedded system to monitor a parameter and transfer the significant data to the monitoring unit for further analyses. The use of wearable sensors has played a quite important role to monitor physiological parameters of a person to minimize any malfunctioning happening in the body. The paper categorizes the work according to the materials used for designing the system, the network protocols and different types of activities that were being monitored. The challenges faced by the current sensing systems and future opportunities for the wearable flexible sensors regarding its market values are also briefly explained in the paper.

Wearable Flexible Sensors: A Review

KAUST Repository

Nag, Anindya; Mukhopadhyay, Subhas Chandra; Kosel, Jü rgen

2017-01-01

The paper provides a review on some of the significant research work done on wearable flexible sensors (WFS). Sensors fabricated with flexible materials have been attached to a person along with the embedded system to monitor a parameter and transfer the significant data to the monitoring unit for further analyses. The use of wearable sensors has played a quite important role to monitor physiological parameters of a person to minimize any malfunctioning happening in the body. The paper categorizes the work according to the materials used for designing the system, the network protocols and different types of activities that were being monitored. The challenges faced by the current sensing systems and future opportunities for the wearable flexible sensors regarding its market values are also briefly explained in the paper.

Evaluation of flexible endoscope steering using haptic guidance

NARCIS (Netherlands)

Reilink, Rob; Stramigioli, Stefano; Kappers, Astrid M L; Misra, Sarthak

Background: Steering the tip of a flexible endoscope relies on the physician's dexterity and experience. For complex flexible endoscopes, conventional controls may be inadequate. Methods: A steering method based on a multi-degree-of-freedom haptic device is presented. Haptic cues are generated based

Evaluation of flexible endoscope steering using haptic guidance

NARCIS (Netherlands)

Reilink, Rob; Stramigioli, Stefano; Kappers, Astrid M.L.; Misra, Sarthak

2011-01-01

Background - Steering the tip of a flexible endoscope relies on the physician’s dexterity and experience. For complex flexible endoscopes, conventional controls may be inadequate. Methods - A steering method based on a multi-degree-of-freedom haptic device is presented. Haptic cues are generated

Natural flexible dermal armor.

Science.gov (United States)

Yang, Wen; Chen, Irene H; Gludovatz, Bernd; Zimmermann, Elizabeth A; Ritchie, Robert O; Meyers, Marc A

2013-01-04

Fish, reptiles, and mammals can possess flexible dermal armor for protection. Here we seek to find the means by which Nature derives its protection by examining the scales from several fish (Atractosteus spatula, Arapaima gigas, Polypterus senegalus, Morone saxatilis, Cyprinius carpio), and osteoderms from armadillos, alligators, and leatherback turtles. Dermal armor has clearly been developed by convergent evolution in these different species. In general, it has a hierarchical structure with collagen fibers joining more rigid units (scales or osteoderms), thereby increasing flexibility without significantly sacrificing strength, in contrast to rigid monolithic mineral composites. These dermal structures are also multifunctional, with hydrodynamic drag (in fish), coloration for camouflage or intraspecies recognition, temperature and fluid regulation being other important functions. The understanding of such flexible dermal armor is important as it may provide a basis for new synthetic, yet bioinspired, armor materials. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cost-Benefit Analysis of Flexibility Retrofits for Coal and Gas-Fueled Power Plants: August 2012 - December 2013

Energy Technology Data Exchange (ETDEWEB)

Venkataraman, S. [GE Energy, Schenectady, NY (United States); Jordan, G. [GE Energy, Schenectady, NY (United States); O' Connor, M. [GE Energy, Schenectady, NY (United States); Kumar, N. [Intertek AIM, Sunnyvale, CA (United States); Lefton, S. [Intertek AIM, Sunnyvale, CA (United States); Lew, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Brinkman, G. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Palchak, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cochran, J. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2013-12-01

High penetrations of wind and solar power plants can induce on/off cycling and ramping of fossil-fueled generators. This can lead to wear-and-tear costs and changes in emissions for fossil-fueled generators. Phase 2 of the Western Wind and Solar Integration Study (WWSIS-2) determined these costs and emissions and simulated grid operations to investigate the full impact of wind and solar on the fossil-fueled fleet. This report studies the costs and benefits of retrofitting existing units for improved operational flexibility (i.e., capability to turndown lower, start and stop faster, and ramp faster between load set-points).

QUALITY EVALUATION OF THE TPP POWER GENERATING UNITS WEAR RECONDITIONING

Directory of Open Access Journals (Sweden)

E. M. Farhadzadeh

2016-01-01

Full Text Available Reconditioning of the power generating unit worn equipment and devices is conducted during the scheduled repair period. Quality of wear reconditioning is evaluated by technical state and repair work implementation. Quality of the repair work execution characterizes logistical activities of the power station and the repair services and is rated by a five-grade scale. There are three technical conditions: adequate, subject to reservations, falling short of the technical standard documentation requirements. In practical work these constraints give place to essential ambiguity of the decision. Further to regulating techniques by way of informational support, the authors propose conducting the wear-reconditioning quality evaluation (repair quality accordingly the technical-and-economic indexes pattern of change. The paper recommends applying similarly the fivegrade system in evaluating the power generating unit technical state and distinguishes intolerable, dissatisfactory, fair, good and model estimates. The study demonstrates the assessment criteria dependence on the character of reliability and economical efficiency of performance variation after the repair with increase or decrease of the technical-and-economic indexes in reference to their mean, minimum and maximum values before the repair. The cases ascribed to intolerable quality of the wear reconditioning are those with one or more technical-and-economic indexes that not only failed to improve their values but deteriorated, and at that they became the worst amongst observable values. The model quality estimate of the wear reconditioning is allotted under condition that the power unit technical-and-economic index valuations after the repair not merely improved but also exceeded the best among those under observation. The developed method and algorithm for quality evaluation of the scheduled repair implementation contribute to practical realization of the independent monitoring. This monitoring

Intrinsic flexibility of porous materials; theory, modelling and the flexibility window of the EMT zeolite framework

International Nuclear Information System (INIS)

Fletcher, Rachel E.; Wells, Stephen A.; Leung, Ka Ming; Edwards, Peter P.; Sartbaeva, Asel

2015-01-01

Framework materials possess intrinsic flexibility which can be investigated using geometric simulation. We review framework flexibility properties in energy materials and present novel results on the flexibility window of the EMT zeolite framework containing 18-crown-6 ether as a structure directing agent (SDA). Framework materials have structures containing strongly bonded polyhedral groups of atoms connected through their vertices. Typically the energy cost for variations of the inter-polyhedral geometry is much less than the cost of distortions of the polyhedra themselves – as in the case of silicates, where the geometry of the SiO 4 tetrahedral group is much more strongly constrained than the Si—O—Si bridging angle. As a result, framework materials frequently display intrinsic flexibility, and their dynamic and static properties are strongly influenced by low-energy collective motions of the polyhedra. Insight into these motions can be obtained in reciprocal space through the ‘rigid unit mode’ (RUM) model, and in real-space through template-based geometric simulations. We briefly review the framework flexibility phenomena in energy-relevant materials, including ionic conductors, perovskites and zeolites. In particular we examine the ‘flexibility window’ phenomenon in zeolites and present novel results on the flexibility window of the EMT framework, which shed light on the role of structure-directing agents. Our key finding is that the crown ether, despite its steric bulk, does not limit the geometric flexibility of the framework

The Geographical Aspect of Flexibility in Distribution Grids

DEFF Research Database (Denmark)

Kouzelis, Konstantinos; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

2015-01-01

, the reason for this is that flexibility is a multidimensional commodity. It can be associated with a unit or a system, a time-frame and a time-horizon of measuring it, its power magnitude and ramp rate, its energy shifting capability, its location and several other features. In this paper, the locational...... aggregation taking into account the distribution grid's radial structure. By aggregating the flexibility in this manner, different geographical points for offering it are defined. Through an illustrative market scenario, it is demonstrated how utilities might profit from their local flexibility by assisting...

Optimal Thermal Unit Commitment Solution integrating Renewable Energy with Generator Outage

Directory of Open Access Journals (Sweden)

S. Sivasakthi

2017-06-01

Full Text Available The increasing concern of global climate changes, the promotion of renewable energy sources, primarily wind generation, is a welcome move to reduce the pollutant emissions from conventional power plants. Integration of wind power generation with the existing power network is an emerging research field. This paper presents a meta-heuristic algorithm based approach to determine the feasible dispatch solution for wind integrated thermal power system. The Unit Commitment (UC process aims to identify the best feasible generation scheme of the committed units such that the overall generation cost is reduced, when subjected to a variety of constraints at each time interval. As the UC formulation involves many variables and system and operational constraints, identifying the best solution is still a research task. Nowadays, it is inevitable to include power system reliability issues in operation strategy. The generator failure and malfunction are the prime influencing factor for reliability issues hence they have considered in UC formulation of wind integrated thermal power system. The modern evolutionary algorithm known as Grey Wolf Optimization (GWO algorithm is applied to solve the intended UC problem. The potential of the GWO algorithm is validated by the standard test systems. Besides, the ramp rate limits are also incorporated in the UC formulation. The simulation results reveal that the GWO algorithm has the capability of obtaining economical resolutions with good solution quality.

Capacity enhancement and flexible operation of unified power quality conditioner in smart and microgrid network

Directory of Open Access Journals (Sweden)

Shafiuzzaman Khan Khadem

2018-01-01

Full Text Available This paper presents a new approach to design Unified Power Quality Conditioner (UPQC, termed as distributed UPQC (D-UPQC, for smart or microgrid network where capacity enhancement and flexible operation of UPQC are the important issues. This paper shows the possibility of capacity enhancement and operational flexibility of UPQC through a coordinated control of existing resources. This UPQC consists of a single unit series active power filter (APFse and multiple shunt APF (APFsh units in a distributed (parallel mode. These units can be connected with a common/separate dc linked capacitor(s. The requirement of capacity enhancement arises from the flexibility to cope up with the increased harmonic load demand at low voltage (LV distribution network. This can be accomplished by a coordinated control where multiple APFsh units are operated by utilizing the capacity of APFse while it is in idle/low mode using. Operational flexibility can be accomplished by compensating (i the reactive and harmonic current individually or (ii splitting the combined reactive and harmonic current/power among the APFsh units. Design and control issues have been discussed to identify the capacity enhancement limit with the possibility of operational flexibility. A system then has been simulated in MATLAB to show the effectiveness of D-UPQC in capacity enhancement and flexible operation by applying its existing resource utilization capability.

Cognitive flexibility and undergraduate physiology students: increasing advanced knowledge acquisition within an ill-structured domain.

Science.gov (United States)

Rhodes, Ashley E; Rozell, Timothy G

2017-09-01

Cognitive flexibility is defined as the ability to assimilate previously learned information and concepts to generate novel solutions to new problems. This skill is crucial for success within ill-structured domains such as biology, physiology, and medicine, where many concepts are simultaneously required for understanding a complex problem, yet the problem consists of patterns or combinations of concepts that are not consistently used or needed across all examples. To succeed within ill-structured domains, a student must possess a certain level of cognitive flexibility: rigid thought processes and prepackaged informational retrieval schemes relying on rote memorization will not suffice. In this study, we assessed the cognitive flexibility of undergraduate physiology students using a validated instrument entitled Student's Approaches to Learning (SAL). The SAL evaluates how deeply and in what way information is processed, as well as the investment of time and mental energy that a student is willing to expend by measuring constructs such as elaboration and memorization. Our results indicate that students who rely primarily on memorization when learning new information have a smaller knowledge base about physiological concepts, as measured by a prior knowledge assessment and unit exams. However, students who rely primarily on elaboration when learning new information have a more well-developed knowledge base about physiological concepts, which is displayed by higher scores on a prior knowledge assessment and increased performance on unit exams. Thus students with increased elaboration skills possibly possess a higher level of cognitive flexibility and are more likely to succeed within ill-structured domains. Copyright © 2017 the American Physiological Society.

Fuqing nuclear power of nuclear steam turbine generating unit No.1 at the implementation and feedback

International Nuclear Information System (INIS)

Cao Yuhua; Xiao Bo; He Liu; Huang Min

2014-01-01

The article introduces the Fuqing nuclear power of nuclear steam turbine generating unit no.l purpose, range of experience, experiment preparation, implementation, feedback and response. Turn of nuclear steam turbo-generator set flush, using the main reactor coolant pump and regulator of the heat generated by the electric heating element and the total heat capacity in secondary circuit of reactor coolant system (steam generator secondary side) of saturated steam turbine rushed to 1500 RPM, Fuqing nuclear power of nuclear steam turbine generating unit no.1 implementation of the performance of the inspection of steam turbine and its auxiliary system, through the test problems found in the clean up in time, the nuclear steam sweep turn smooth realization has accumulated experience. At the same time, Fuqing nuclear power of nuclear steam turbine generating unit no.1 at turn is half speed steam turbine generator non-nuclear turn at the first, with its smooth realization of other nuclear power steam turbine generator set in the field of non-nuclear turn play a reference role. (authors)

Supporting an Object-Oriented Approach to Unit Generator Development: The Csound Plugin Opcode Framework

Directory of Open Access Journals (Sweden)

Victor Lazzarini

2017-09-01

Full Text Available This article presents a new framework for unit generator development for Csound, supporting a full object-oriented programming approach. It introduces the concept of unit generators and opcodes, and its centrality with regards to music programming languages in general, and Csound in specific. The layout of an opcode from the perspective of the Csound C-language API is presented, with some outline code examples. This is followed by a discussion which places the unit generator within the object-oriented paradigm and the motivation for a full C++ programming support, which is provided by the Csound Plugin Opcode Framework (CPOF. The design of CPOF is then explored in detail, supported by several opcode examples. The article concludes by discussing two key applications of object-orientation and their respective instances in the Csound code base.

Flexibility-enabling Contracts in Electricity Markets

DEFF Research Database (Denmark)

Boscan, Luis; Poudineh, Rahmatallah

As the share of intermittent renewable energy increases in the generation mix, power systems are exposed to greater levels of uncertainty and risk, which requires planners, policy and business decision makers to incentivise flexibility, that is: their adaptability to unforeseen variations....... Additionally, along with traditional sources, which already enable flexibility, a number of business models, such as thermostat-based demand response, aggregators and small storage providers, are emerging in electricity markets and expected to constitute important sources of flexibility in future decentralised...... power systems. However, due to presence of high transaction costs, relative to the size of resource, the emerging small resources cannot directly participate in an organised electricity market and/or compete. This paper asks the fundamental question of how should the provision of flexibility, as a multi...

Diagnostic testing and repair of Hollingsworth Generating Station`s Unit One

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-31

This paper presents a case history of the diagnosis of a hydroelectric generator problem and the corrections implemented. The problem involved an excessive rotor imbalance coupled with a static air gap imbalance that cause severe load-sensitive vibrations. The problem constrained the plant from operating the generator unit throughout the range of its nameplate rating and caused periodic failure of the generator guide and thrust bearing. The paper describes the vibration survey and mechanical survey of the generator rotor, the pre-overhaul diagnosis, the repairs undertaken to the rotor, and the generator performance after the repair, with comparison to the pre-repair condition. The paper concludes with a discussion of the economic, operational, and logistic issues involved in the overhaul.

Next Generation Flexible and Cognitive Heterogeneous Optical Networks

DEFF Research Database (Denmark)

Tomkos, Ioannis; Angelou, Marianna; Barroso, Ramón J. Durán

2012-01-01

Optical networking is the cornerstone of the Future Internet as it provides the physical infrastructure of the core backbone networks. Recent developments have enabled much better quality of service/experience for the end users, enabled through the much higher capacities that can be supported...... the capabilities of the Future Internet. In this book chapter, we highlight the latest activities of the optical networking community and in particular what has been the focus of EU funded research. The concepts of flexible and cognitive optical networks are introduced and their key expected benefits...

A portable gas recirculation unit for gaseous detectors

Science.gov (United States)

Guida, R.; Mandelli, B.

2017-10-01

The use of greenhouse gases (usually C2H2F4, CF4 and SF6) is sometimes necessary to achieve the required performance for some gaseous detectors. The consumption of these gases in the LHC systems is reduced by recycling the gas mixture thanks to a complex gas recirculation system. Beyond greenhouse gas consumption due to LHC systems, a considerable contribution is generated by setups used for LHC detector upgrade projects, R&D activities, detector quality assurance or longevity tests. In order to minimise this emission, a new flexible and portable gas recirculation unit has been developed. Thanks to its low price, flexibility and user-friendly operation it can be easily adapted for the different types of detector systems and set-ups.

Search and Retrieval of Foreign Objects for the Steam Generator of Wolsung NPP Unit 1

Energy Technology Data Exchange (ETDEWEB)

Jeong, Woo-Tae; Lee, Kyung-Ho [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

We developed a foreign object search and retrieval (FOSAR) system for Wolsung NPP unit 1 steam generators. The steam generators of Wolsung NPP unit 1 have one 2.5 inch hand hole and two 4 inch hand holes. The FOSAR system was designed to be installed through 4 inch hand holes. Using permanent magnet, the FOSAR system was firmly attached to the vertical annulus wall of the steam generator. We successfully developed the FOSAR system for Wolsung NPP unit 1. Using the developed FOSAR system, technicians successfully found and removed various foreign objects. Most of the foreign objects, we found, were made of carbon steel sheet, therefore magnet tool was the most useful to remove it. Alligator tool was sometimes used. Based on the experience during the FOSAR activities, we are developing a lancing system for Wolsung NPP unit 1. It will be designed and manufactured until November 2016.

Search and Retrieval of Foreign Objects for the Steam Generator of Wolsung NPP Unit 1

International Nuclear Information System (INIS)

Jeong, Woo-Tae; Lee, Kyung-Ho

2016-01-01

We developed a foreign object search and retrieval (FOSAR) system for Wolsung NPP unit 1 steam generators. The steam generators of Wolsung NPP unit 1 have one 2.5 inch hand hole and two 4 inch hand holes. The FOSAR system was designed to be installed through 4 inch hand holes. Using permanent magnet, the FOSAR system was firmly attached to the vertical annulus wall of the steam generator. We successfully developed the FOSAR system for Wolsung NPP unit 1. Using the developed FOSAR system, technicians successfully found and removed various foreign objects. Most of the foreign objects, we found, were made of carbon steel sheet, therefore magnet tool was the most useful to remove it. Alligator tool was sometimes used. Based on the experience during the FOSAR activities, we are developing a lancing system for Wolsung NPP unit 1. It will be designed and manufactured until November 2016

Flexible interaction of plug-in electric vehicle parking lots for efficient wind integration

International Nuclear Information System (INIS)

Heydarian-Forushani, E.; Golshan, M.E.H.; Shafie-khah, M.

2016-01-01

Highlights: • Interactive incorporation of plug-in electric vehicle parking lots is investigated. • Flexible energy and reserve services are provided by electric vehicle parking lots. • Uncertain characterization of electric vehicle owners’ behavior is taken into account. • Coordinated operation of parking lots can facilitate wind power integration. - Abstract: The increasing share of uncertain wind generation has changed traditional operation scheduling of power systems. The challenges of this additional variability raise the need for an operational flexibility in providing both energy and reserve. One key solution is an effective incorporation of plug-in electric vehicles (PEVs) into the power system operation process. To this end, this paper proposes a two-stage stochastic programming market-clearing model considering the network constraints to achieve the optimal scheduling of conventional units as well as PEV parking lots (PLs) in providing both energy and reserve services. Different from existing works, the paper pays more attention to the uncertain characterization of PLs takes into account the arrival/departure time of PEVs to/from the PL, the initial state of charge (SOC) of PEVs, and their battery capacity through a set of scenarios in addition to wind generation scenarios. The results reveal that although the cost saving as a consequence of incorporating PL to the grid is below 1% of total system cost, however, flexible interactions of PL in the energy and reserve markets can promote the integration of wind power more than 13.5%.

Financing the next generation of new reactors in the united states. Panel Discussion

International Nuclear Information System (INIS)

Turner, Kyle; Simard, Ron; Tran, K.C.; Kelly, Patrick; Green, Barrett E.; Quinn, Edward L.; Stamos, John

2001-01-01

Full text of publication follows: With the California energy shortage and new growth forecasts in the United States, significant new base-load generation will be needed in the near future to meet electricity demands. New figures for growth in electricity demand for the United States rose significantly because of Internet and related business expansion. Lack of sufficient natural gas supplies to support new generation in some regions is causing a renewed interest in building new nuclear plants. Speakers will address the current status of available and near-term design options including both the U.S. Department of Energy Generation III and IV design packages, infrastructure challenges, and financial models that show that nuclear is competitive with alternatives and a prudent and profitable investment. (authors)

Effect of Cooling Units on the Performance of an Automotive Exhaust-Based Thermoelectric Generator

Science.gov (United States)

Su, C. Q.; Zhu, D. C.; Deng, Y. D.; Wang, Y. P.; Liu, X.

2017-05-01

Currently, automotive exhaust-based thermoelectric generators (AETEGs) are a hot topic in energy recovery. In order to investigate the influence of coolant flow rate, coolant flow direction and cooling unit arrangement in the AETEG, a thermoelectric generator (TEG) model and a related test bench are constructed. Water cooling is adopted in this study. Due to the non-uniformity of the surface temperature of the heat source, the coolant flow direction would affect the output performance of the TEG. Changing the volumetric flow rate of coolant can increase the output power of multi-modules connected in series or/and parallel as it can improve the temperature uniformity of the cooling unit. Since the temperature uniformity of the cooling unit has a strong influence on the output power, two cooling units are connected in series or parallel to research the effect of cooling unit arrangements on the maximum output power of the TEG. Experimental and theoretical analyses reveal that the net output power is generally higher with cooling units connected in parallel than cooling units connected in series in the cooling system with two cooling units.

Accelerating Pseudo-Random Number Generator for MCNP on GPU

Science.gov (United States)

Gong, Chunye; Liu, Jie; Chi, Lihua; Hu, Qingfeng; Deng, Li; Gong, Zhenghu

2010-09-01

Pseudo-random number generators (PRNG) are intensively used in many stochastic algorithms in particle simulations, artificial neural networks and other scientific computation. The PRNG in Monte Carlo N-Particle Transport Code (MCNP) requires long period, high quality, flexible jump and fast enough. In this paper, we implement such a PRNG for MCNP on NVIDIA's GTX200 Graphics Processor Units (GPU) using CUDA programming model. Results shows that 3.80 to 8.10 times speedup are achieved compared with 4 to 6 cores CPUs and more than 679.18 million double precision random numbers can be generated per second on GPU.

PseKNC: a flexible web server for generating pseudo K-tuple nucleotide composition.

Science.gov (United States)

Chen, Wei; Lei, Tian-Yu; Jin, Dian-Chuan; Lin, Hao; Chou, Kuo-Chen

2014-07-01

The pseudo oligonucleotide composition, or pseudo K-tuple nucleotide composition (PseKNC), can be used to represent a DNA or RNA sequence with a discrete model or vector yet still keep considerable sequence order information, particularly the global or long-range sequence order information, via the physicochemical properties of its constituent oligonucleotides. Therefore, the PseKNC approach may hold very high potential for enhancing the power in dealing with many problems in computational genomics and genome sequence analysis. However, dealing with different DNA or RNA problems may need different kinds of PseKNC. Here, we present a flexible and user-friendly web server for PseKNC (at http://lin.uestc.edu.cn/pseknc/default.aspx) by which users can easily generate many different modes of PseKNC according to their need by selecting various parameters and physicochemical properties. Furthermore, for the convenience of the vast majority of experimental scientists, a step-by-step guide is provided on how to use the current web server to generate their desired PseKNC without the need to follow the complicated mathematical equations, which are presented in this article just for the integrity of PseKNC formulation and its development. It is anticipated that the PseKNC web server will become a very useful tool in computational genomics and genome sequence analysis. Copyright © 2014 Elsevier Inc. All rights reserved.

Electro Spray Method for Flexible Display

Science.gov (United States)

2016-05-12

AFRL-AFOSR-JP-TR-2016-0095 Electro Spray Method for Flexible Display Yukiharu Uraoka NARA INSTITUTE OF SCIENCE AND TECHNOLOGY Final Report 11/26/2016...DATES COVERED (From - To)  20 Mar 2013 to 19 May 2016 4. TITLE AND SUBTITLE Electro Spray Method for Flexible Display 5a.  CONTRACT NUMBER 5b.  GRANT...NUMBER FA2386-13-1-4024 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Yukiharu Uraoka 5d.  PROJECT NUMBER 5e.  TASK NUMBER 5f.   WORK UNIT NUMBER 7

Application of flexible scope in large testing laboratories

Directory of Open Access Journals (Sweden)

Carina Di Candia

2011-04-01

Full Text Available According as the international definition of Flexible Scope, a laboratory must demonstrate face with the accreditation body that it has the knowledge, experience and competence to work within the full range of its flexible scope, as well as possessing suitable laboratory environments and equipment. The laboratory must also demonstrate that it has a management system in place that can control its proposed approach while continuing to comply with the requirements of ISO 17025:2005. In case of UKAS (Unites Kingdom Accreditation Service, prior to offering accreditation for flexible scope they must have a high degree of confidence that the staff are technically competent and that the management system controlling certain key processes as development, review, validation and authorization.LATU apply these requirements since 2004 as "Unified Tests". Until this date, LATU was doing the same type of tests in different materials departments using different equipment, personal, and testing quality control. In order to that were defined cross disciplinary groups to analyze this topic approaching in personal competence and quality control tests improvement, and resource's decrease. For example, LATU has the Unified Test Tensile Strength accredited by UKAS in: corrugated and solid fiberboard, paper board, linerboard, cork plugs, plastic bags, plastic sheeting, paper, woven fabrics, plastic woven bags and woven plastic. As a result of the Unified Tests was generated a general unified manage procedure with unified criteria's, responsibilities and actions. Was written a unique testing procedure not only with the actual flexible scope and the flexibilities limits but also the compliance requirements of ISO 17025 and the accreditations body methodology. We could decrease the amount of documentation to control. Was defined the methodology and implemented periodicaly internal inter comparisons between departments in order to valid the unified tests and has a unique

FIND: Douglas Point Nuclear Generating Station, Units 1 and 2

International Nuclear Information System (INIS)

Moore, M.M.

1975-12-01

This index is presented as a guide to microfiche items 1 through 136 in Docket 50448, which was assigned to Potomac Electric Power Company's Application for Licenses to construct and operate Douglas Point Nuclear Generating Station, Units 1 and 2. Information received from August, 1973 through July, 1975 is included

Transparent and Flexible Self-Charging Power Film and Its Application in a Sliding Unlock System in Touchpad Technology.

Science.gov (United States)

Luo, Jianjun; Tang, Wei; Fan, Feng Ru; Liu, Chaofeng; Pang, Yaokun; Cao, Guozhong; Wang, Zhong Lin

2016-08-23

Portable and wearable personal electronics and smart security systems are accelerating the development of transparent, flexible, and thin-film electronic devices. Here, we report a transparent and flexible self-charging power film (SCPF) that functions either as a power generator integrated with an energy storage unit or as a self-powered information input matrix. The SCPF possesses the capability of harvesting mechanical energy from finger motions, based on the coupling between the contact electrification and electrostatic induction effects, and meanwhile storing the generated energy. Under the fast finger sliding, the film can be charged from 0 to 2.5 V within 2094 s and discharge at 1 μA for approximately 1630 s. Furthermore, the film is able to identify personal characteristics during a sliding motion by recording the electric signals related to the person's individual bioelectricity, applied pressing force, sliding speed, and so on, which shows its potential applications in security systems in touchpad technology.

Evolving Distributed Generation Support Mechanisms: Case Studies from United States, Germany, United Kingdom, and Australia (Chinese translation)

Energy Technology Data Exchange (ETDEWEB)

Zhou, Shengru [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lowder, Travis R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tian, Tian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-09-07

This is the Chinese translation of NREL/TP-6A20-67613. This report expands on a previous National Renewable Energy Laboratory (NREL) technical report (Lowder et al. 2015) that focused on the United States' unique approach to distributed generation photovoltaics (DGPV) support policies and business models. While the focus of that report was largely historical (i.e., detailing the policies and market developments that led to the growth of DGPV in the United States), this report looks forward, narrating recent changes to laws and regulations as well as the ongoing dialogues over how to incorporate distributed generation (DG) resources onto the electric grid. This report also broadens the scope of Lowder et al. (2015) to include additional countries and technologies. DGPV and storage are the principal technologies under consideration (owing to market readiness and deployment volumes), but the report also contemplates any generation resource that is (1) on the customer side of the meter, (2) used to, at least partly, offset a host's energy consumption, and/or (3) potentially available to provide grid support (e.g., through peak shaving and load shifting, ancillary services, and other means).

IEA EBC Annex 67 Energy Flexible Buildings

DEFF Research Database (Denmark)

Marszal, Anna Joanna; Jensen, Søren Østergaard

2016-01-01

know ledge on and demonstration of the Energy Flexibility Buildings can provide for the energy grids as well of to identify critical aspects and possible solutions to manage this Energy Flexibility. The paper discusses the background, the aims and the work plan of IEA (International Energy Agency) EBC......The foreseen large deployment of renewable energy sources may seriously affect the stability of energy grids. It will be necessary to control energy consumption to match instantaneous energy production. The built-in Energy Flexibility in buildings may be utilized for stabilizing the energy grids......, allowing for a larger roll out of renewable technologies. The Energy Flexibility of a building is the ability to manage its energy demand and generation according to local climate conditions, user needs and grid requirements. Energy Flexibility of buildings will thus allow for demand side management...

Advanced Stirling Radioisotope Generator Engineering Unit 2 (ASRG EU2) Final Assembly

Science.gov (United States)

Oriti, Salvatore M.

2015-01-01

NASA Glenn Research Center (GRC) has recently completed the assembly of a unique Stirling generator test article for laboratory experimentation. Under the Advanced Stirling Radioisotope Generator (ASRG) flight development contract, NASA GRC initiated a task to design and fabricate a flight-like generator for in-house testing. This test article was given the name ASRG Engineering Unit 2 (EU2) as it was effectively the second engineering unit to be built within the ASRG project. The intent of the test article was to duplicate Lockheed Martin's qualification unit ASRG design as much as possible to enable system-level tests not previously possible at GRC. After the cancellation of the ASRG flight development project, the decision was made to continue the EU2 build, and make use of a portion of the hardware from the flight development project. GRC and Lockheed Martin engineers collaborated to develop assembly procedures, leveraging the valuable knowledge gathered by Lockheed Martin during the ASRG development contract. The ASRG EU2 was then assembled per these procedures at GRC with Lockheed Martin engineers on site. The assembly was completed in August 2014. This paper details the components that were used for the assembly, and the assembly process itself.

Intelligent Flexible Materials for Space Structures: Expandable Habitat Engineering Development Unit

Science.gov (United States)

Hinkle, Jon; Sharpe, George; Lin, John; Wiley, Cliff; Timmers, Richard

2010-01-01

Expandable habitable elements are an enabling technology for human exploration in space and on planetary surfaces. Large geometries can be deployed from a small launch volume, allowing greater mission capability while reducing mass and improving robustness over traditional rigid shells. This report describes research performed by ILC Dover under the Intelligent Flexible Materials for Space Structures program on the design and manufacture of softgoods for LaRC's Expandable Habitat Engineering Development Unit (EDU). The EDU is a full-scale structural test article of an expandable hybrid habitat, integrating an expandable softgoods center section with two rigid end caps. The design of the bladder, restraint layer and a mock-up Thermal Micrometeoroid Cover is detailed together with the design of the interface hardware used to attach them to the end caps. The integration and design of two windows and a floor are also covered. Analysis was performed to study the effects of the open weave design, and to determine the correct webbing and fabric configuration. Stress analyses were also carried out on the interfaces between the softgoods and the end caps and windows. Testing experimentally determined the strength of the fabric and straps, and component testing was used to proof several critical parts of the design. This program established new manufacturing and design techniques that can be applied to future applications in expandable structures.

Heating unit of Berovo by co-generation (Macedonia)

International Nuclear Information System (INIS)

Armenski, Slave; Dimitrov, Konstantin; Tashevski, Done

1999-01-01

A plant for combined heat and electric power production, for central heating of the town Berovo (Macedonia) is proposed. The common reason to use a co-generation unit is the energy efficiency and a significant reduction of environmental pollution. The heat consumption of town Berovo is analyzed and determined. Based on the energy consumption of a whole power plant, e. i. the plant for combined and simultaneous production of power is proposed. The quantity of annually heat and electrical production and annually coal consumption are estimated. (Author)

Motor unit firing rate patterns during voluntary muscle force generation: a simulation study

Science.gov (United States)

Hu, Xiaogang; Rymer, William Z.; Suresh, Nina L.

2014-04-01

Objective. Muscle force is generated by a combination of motor unit (MU) recruitment and changes in the discharge rate of active MUs. There have been two basic MU recruitment and firing rate paradigms reported in the literature, which describe the control of the MUs during force generation. The first (termed the reverse ‘onion skin’ profile), exhibits lower firing rates for lower threshold units, with higher firing rates occurring in higher threshold units. The second (termed the ‘onion skin’ profile), exhibits an inverse arrangement, with lower threshold units reaching higher firing rates. Approach. Using a simulation of the MU activity in a hand muscle, this study examined the force generation capacity and the variability of the muscle force magnitude at different excitation levels of the MU pool under these two different MU control paradigms. We sought to determine which rate/recruitment scheme was more efficient for force generation, and which scheme gave rise to the lowest force variability. Main results. We found that the force output of both firing patterns leads to graded force output at low excitation levels, and that the force generation capacity of the two different paradigms diverged around 50% excitation. In the reverse ‘onion skin’ pattern, at 100% excitation, the force output reached up to 88% of maximum force, whereas for the ‘onion skin’ pattern, the force output only reached up to 54% of maximum force at 100% excitation. The force variability was lower at the low to moderate force levels under the ‘onion skin’ paradigm than with the reverse ‘onion skin’ firing patterns, but this effect was reversed at high force levels. Significance. This study captures the influence of MU recruitment and firing rate organization on muscle force properties, and our results suggest that the different firing organizations can be beneficial at different levels of voluntary muscle force generation and perhaps for different tasks.

Design of double-fed control system for J-TEXT 100 MVA pulse generator unit

International Nuclear Information System (INIS)

Fang, Jianming; Yu, Kexun; Zhang, Ming; Zhuang, Ge; Xiao, Zhiguo; Jiang, Guozhong; Yang, Cheng; Xu, Jiayu

2013-01-01

Highlights: ► A double-fed control system is designed for J-TEXT 100 MVA pulse generator unit. ► The double-fed system can control the motor speed and reactive power individually. ► Experiment on a prototype motor shows a good control result. -- Abstract: The 100 MVA pulse generator unit is the main power supply of J-TEXT. This unit supplies energy for the toroidal coil, the ohmic heat coil and the divertor coil, with the maximum stored energy 185 MJ. For the difference of grid frequency between China and USA, the rotational speed and stored energy of this unit are less than the designed value. A double-fed control system for the unit is designed to raise them. This double-fed system has applied a control method using a rotational reference frame oriented by stator flux. With this control system, the speed and reactive power of motor could be controlled individually. Experiments on a prototype motor show a good control result

Cernavoda NPP Unit 1 - a plant of several generations

International Nuclear Information System (INIS)

Rotaru, I.; Metes, M.; Anghelescu, M.S.

2001-01-01

The paper reflects some key aspects related to the shift of generations during the project's development, including the present stage. Further, the place of Cernavoda NPP Unit 1 in the Romanian power sector and among other nuclear stations in the world is presented. The operational performances achieved 'in service' up to the end of 1999, with reference to the performance indicators for electrical energy production, nuclear safety, radiation protection, radioactive wastes and nuclear fuel are illustrated. For all of these items, comparisons are performed with similar indicators reported by other worldwide nuclear power plants, in order to assess our results. Finally, some comments about Cernavoda NPP Unit 2 project status and need to completion and commissioning it are included. (authors)

The effect of chordwise flexibility on flapping foil propulsion in quiescent fluid

Science.gov (United States)

Shinde, Sachin; Arakeri, Jaywant

2010-11-01

Motivated to understand the role of wing flexibility of flying creatures during hovering, we experimentally study the effect of chordwise flexibility on the flow generated in quiescent fluid by a sinusoidally pitching rigid symmetrical foil with a flexible flap attached at the trailing edge. This foil produces a narrow, coherent jet containing reverse Karman vortex street, and a corresponding thrust. The thrust and flow is similar to that produced by a hovering bird or insect, however the mechanism seems to be different from known hovering mechanisms. Novelty of the present hovering mechanism is that the thrust generation is due to the coordinated pushing action of rigid foil and flexible flap. We identify the flow and vortex generation mechanism. This foil produces jet flows over a range of flapping frequencies and amplitudes. In contrast, the foil without flap i.e. with rigid trailing edge produces a weak, divergent jet that meanders randomly. Appending a flexible flap to the foil suppresses jet-meandering and strengthens the jet. Flexibility of flap is crucial in determining the flow structure. This study is useful in designing MAVs and thrusters.

Vibration Spectrum Analysis for Indicating Damage on Turbine and Steam Generator Amurang Unit 1

Directory of Open Access Journals (Sweden)

Beny Cahyono

2017-12-01

Full Text Available Maintenance on machines is a mandatory asset management activity to maintain asset reliability in order to reduce losses due to failure. 89% of defects have random failure mode, the proper maintenance method is predictive maintenance. Predictive maintenance object in this research is Steam Generator Amurang Unit 1, which is predictive maintenance is done through condition monitoring in the form of vibration analysis. The conducting vibration analysis on Amurang Unit 1 Steam Generator is because vibration analysis is very effective on rotating objects. Vibration analysis is predicting the damage based on the vibration spectrum, where the vibration spectrum is the result of separating time-based vibrations and simplifying them into vibrations based on their frequency domain. The transformation of time-domain-wave into frequency-domain-wave is using the application of FFT, namely AMS Machinery. The measurement of vibration value is done on turbine bearings and steam generator of Unit 1 Amurang using Turbine Supervisory Instrument and CSI 2600 instrument. The result of this research indicates that vibration spectrum from Unit 1 Amurang Power Plant indicating that there is rotating looseness, even though the vibration value does not require the Unit 1 Amurang Power Plant to stop operating (shut down. This rotating looseness, at some point, can produce some indications that similar with the unbalance. In order to avoid more severe vibrations, it is necessary to do inspection on the bearings in the Amurang Unit 1 Power Plant.

76 FR 24064 - Arizona Public Service Company, Palo Verde Nuclear Generating Station, Units 1, 2, and 3, Notice...

Science.gov (United States)

2011-04-29

... Service Company, Palo Verde Nuclear Generating Station, Units 1, 2, and 3, Notice of Issuance of Renewed... Company (licensee), the operator of the Palo Verde Nuclear Generating Station, Units 1, 2, and 3 (PVNGS... Plants: Supplement 43, Regarding Palo Verde Nuclear Generating Station,'' issued January 2011, discusses...

New generation nuclear power units of PWR type integral reactors

International Nuclear Information System (INIS)

Mitenkov, F.M.; Kurachen Kov, A.V.; Malamud, V.A.; Panov, Yu.K.; Runov, B.I.; Flerov, L.N.

1997-01-01

Design bases of new generation nuclear power units (nuclear power plants - NPP, nuclear co-generation plants - NCP, nuclear distract heating plants - NDHP), using integral type PWPS, developed in OKBM, Nizhny Novgorod and trends of design decisions optimization are considered in this report. The problems of diagnostics, servicing and repair of the integral reactor components in course of operation are discussed. The results of safety analysis, including the problems of several accident localization with postulated core melting and keeping corium in the reactor vessel and guard vessel are presented. Information on experimental substantiation of the suggested plant design decisions is presented. (author)

Integrating generation and transmission networks reliability for unit commitment solution

International Nuclear Information System (INIS)

Jalilzadeh, S.; Shayeghi, H.; Hadadian, H.

2009-01-01

This paper presents a new method with integration of generation and transmission networks reliability for the solution of unit commitment (UC) problem. In fact, in order to have a more accurate assessment of system reserve requirement, in addition to unavailability of generation units, unavailability of transmission lines are also taken into account. In this way, evaluation of the required spinning reserve (SR) capacity is performed by applying reliability constraints based on loss of load probability and expected energy not supplied (EENS) indices. Calculation of the above parameters is accomplished by employing a novel procedure based on the linear programming which it also minimizes them to achieve optimum level of the SR capacity and consequently a cost-benefit reliability constrained UC schedule. In addition, a powerful solution technique called 'integer-coded genetic algorithm (ICGA)' is being used for the solution of the proposed method. Numerical results on the IEEE reliability test system show that the consideration of transmission network unavailability has an important influence on reliability indices of the UC schedules

Design of micro, flexible light-emitting diode arrays and fabrication of flexible electrodes

International Nuclear Information System (INIS)

Gao, Dan; Wang, Weibiao; Liang, Zhongzhu; Liang, Jingqiu; Qin, Yuxin; Lv, Jinguang

2016-01-01

In this study, we design micro, flexible light-emitting diode (LED) array devices. Using theoretical calculations and finite element simulations, we analyze the deformation of the conventional single electrode bar. Through structure optimization, we obtain a three-dimensional (3D), chain-shaped electrode structure, which has a greater bending degree. The optimized electrodes not only have a bigger bend but can also be made to spin. When the supporting body is made of polydimethylsiloxane (PDMS), the maximum bending degree of the micro, flexible LED arrays (4  ×  1 arrays) was approximately 230 µ m; this was obtained using the finite element method. The device (4  ×  1 arrays) can stretch to 15%. This paper describes the fabrication of micro, flexible LED arrays using microelectromechancial (MEMS) technology combined with electroplating technology. Specifically, the isolated grooves are made by dry etching which can isolate and protect the light-emitting units. A combination of MEMS technology and wet etching is used to fabricate the large size spacing. (paper)

Flexibility of a combined heat and power system with thermal energy storage for district heating

International Nuclear Information System (INIS)

Nuytten, Thomas; Claessens, Bert; Paredis, Kristof; Van Bael, Johan; Six, Daan

2013-01-01

Highlights: ► A generic model for flexibility assessment of thermal systems is proposed. ► The model is applied to a combined heat and power system with thermal energy storage. ► A centrally located storage offers more flexibility compared to individual units. ► Increasing the flexibility requires both a more powerful CHP and a larger buffer. - Abstract: The trend towards an increased importance of distributed (renewable) energy resources characterized by intermittent operation redefines the energy landscape. The stochastic nature of the energy systems on the supply side requires increased flexibility at the demand side. We present a model that determines the theoretical maximum of flexibility of a combined heat and power system coupled to a thermal energy storage solution that can be either centralized or decentralized. Conventional central heating, to meet the heat demand at peak moments, is also available. The implications of both storage concepts are evaluated in a reference district. The amount of flexibility created in the district heating system is determined by the approach of the system through delayed or forced operation mode. It is found that the distinction between the implementation of the thermal energy storage as a central unit or as a collection of local units, has a dramatic effect on the amount of available flexibility

Testing of the Advanced Stirling Radioisotope Generator Engineering Unit at NASA Glenn Research Center

Science.gov (United States)

Lewandowski, Edward J.

2013-01-01

The Advanced Stirling Radioisotope Generator (ASRG) is a high-efficiency generator being developed for potential use on a Discovery 12 space mission. Lockheed Martin designed and fabricated the ASRG Engineering Unit (EU) under contract to the Department of Energy. This unit was delivered to NASA Glenn Research Center in 2008 and has been undergoing extended operation testing to generate long-term performance data for an integrated system. It has also been used for tests to characterize generator operation while varying control parameters and system inputs, both when controlled with an alternating current (AC) bus and with a digital controller. The ASRG EU currently has over 27,000 hours of operation. This paper summarizes all of the tests that have been conducted on the ASRG EU over the past 3 years and provides an overview of the test results and what was learned.

Micro flexible robot hand using electro-conjugate fluid

Science.gov (United States)

Ueno, S.; Takemura, K.; Yokota, S.; Edamura, K.

2013-12-01

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a flow (ECF flow) when subjected to high DC voltage. Since it only requires a tiny electrode pair in micrometer size in order to generate the ECF flow, the ECF is a promising micro fluid pressure source. This study proposes a novel micro robot hand using the ECF. The robot hand is mainly composed of five flexible fingers and an ECF flow generator. The flexible finger is made of silicone rubber having several chambers in series along its axis. When the chambers are depressurized, the chambers deflate resulting in making the actuator bend. On the other hand, the ECF flow generator has a needle-ring electrode pair inside. When putting the ECF flow generator into the ECF and applying voltage of 6.0 kV to the electrode pair, we can obtain the pressure of 33.1 kPa. Using the components mentioned above, we developed the ECF robot hand. The height, the width and the mass of the robot hand are 45 mm, 40 mm and 5.2 g, respectively. Since the actuator is flexible, the robot hand can grasp various objects with various shapes without complex controller.

Comparative funding consequences of large versus small gas-fired power generation units

International Nuclear Information System (INIS)

Johnson, N.G.

1995-01-01

Gas producers are increasingly looking to privately-owned gas-fired power generation as a major growth market to support the development of new fields being discovered across Australia. Gas-fired generating technology is more environmentally friendly than coal-fired power stations, has lower unit capital costs and has higher efficiency levels. With the recent downward trends in gas prices for power generation (especially in Western Australia) it is likely that gas will indeed be the consistently preferred fuel for generation in Australia. Gas producers should be sensitive to the different financial and risk characteristics of the potential market represented by large versus small gas-fired private power stations. These differences are exaggerated by the much sharper focus given by the private sector to quantify risk and to its allocation to the parties best able to manage it. The significant commercial differences between classes of generation projects result in gas producers themselves being exposed to diverging risk profiles through their gas supply contracts with generating companies. Selling gas to larger generation units results in gas suppliers accepting proportionately (i.e. not just prorata to the larger installed capacity) higher levels of financial risk. Risk arises from the higher probability of a project not being completed, from the increased size of penalty payments associated with non-delivery of gas and from the rising level of competition between gas suppliers. Gas producers must fully understand the economics and risks of their potential electricity customers and full financial analysis will materially help the gas supplier in subsequent commercial gas contract negotiations. (author). 1 photo

Techno-economic optimization of flexible biogas concepts in the context of EEG; Technisch-oekonomische Optimierung von flexiblen Biogaskonzepten im Kontext des EEG

Energy Technology Data Exchange (ETDEWEB)

Barchmann, Tino; Lauer, Markus [DBFZ Deutsches Biomasseforschungszentrum gemeinnuetzige GmbH, Leipzig (Germany)

2014-08-01

Due to the introduction of direct marketing and flexibility premium of renewable energy by the Renewable Energy Act 2012 (EEG 2012), incentives were created to favour a more demand-oriented power supply from biogas plants (BGA). The decision for such an operational mode depends on on-site conversion units on the economic outcome of the plants throughout the whole operating time. To install new plants or transfer existing plants into a flexible mode of operation, investments in additional and more efficient combined heat and power plants (CHP), in additional gas and/or heat storage and other technical components are necessary. The analyses show that the flexibility premium, as an extra of the market premium model, creates the greatest incentive for a more flexible generation of electricity from biogas. In addition, an intelligent management optimization can generate additional revenues on EPEX SPOT SE and balancing energy market. The additional revenues of more demand-oriented power supply from biogas plants are highly dependent on plant-specific conditions. From an economic perspective, a duplication of the installed electrical capacity seems to be the most beneficial option for a transition to a demand-driven operation mode of an average biogas model plant under the current legal framework (EEG 2012).

Flexible, ferroelectric nanoparticle doped polymer dispersed liquid crystal devices for lower switching voltage and nanoenergy generation

Science.gov (United States)

Nimmy John, V.; Varanakkottu, Subramanyan Namboodiri; Varghese, Soney

2018-06-01

Flexible polymer dispersed liquid crystal (F-PDLC) devices were fabricated using transparent conducting ITO/PET film. Polymerization induced phase separation (PIPS) method was used for pure and ferroelectric BaTiO3 (BTO) and ZnO doped PDLC devices. The distribution of nanoparticles in the PDLC and the formation of micro cavities were studied using field emission scanning electron microscopy (FESEM). It was observed that the addition of ferroelectric BTO nanoparticles has reduced the threshold voltage (Vth) and saturation voltage (Vsat) of FNP-PDLC by 85% and 41% respectively due to the spontaneous polarization of ferroelectric nanoparticles. The ferroelectric properties of BTO and ZnO in the fabricated devices were investigated using dynamic contact electrostatic force microscopy (DC EFM). Flexing the device can generate a potential due to the piezo-tribo electric effect of the ferroelectric nanomaterial doped in the PDLC matrix, which could be utilized as an energy generating system. The switching voltage after multiple flexing was also studied and found to be in par with non-flexing situations.

Towards Flexible Self-powered Micro-scale Integrated Systems

KAUST Repository

Rojas, Jhonathan Prieto

2014-04-01

Today’s information-centered world leads the ever-increasing consumer demand for more powerful, multifunctional portable devices. Additionally, recent developments on long-lasting energy sources and compliant, flexible systems, have introduced new required features to the portable devices industry. For example, wireless sensor networks are in urgent need of self-sustainable, easy-to-deploy, mobile platforms, wirelessly interconnected and accessible through a cloud computing system. The objective of my doctoral work is to develop integration strategies to effectively fabricate mechanically flexible, energy-independent systems, which could empower sensor networks for a great variety of new exciting applications. The first module, flexible electronics, can be achieved through several techniques and materials. Our main focus is to bring mechanical flexibility to the state-of-the-art high performing silicon-based electronics, with billions of ultra-low power, nano-sized transistors. Therefore, we have developed a low-cost batch fabrication process to transform standard, rigid, mono-crystalline silicon (100) wafer with devices, into a thin (5-20 m), mechanically flexible, optically semi-transparent silicon fabric. Recycling of the remaining wafer is possible, enabling generation of multiple fabrics to ensure lowcost and optimal utilization of the whole substrate. We have shown mono, amorphous and poly-crystalline silicon and silicon dioxide fabrics, featuring industry’s most advanced high-/metal-gate based capacitors and transistors. The second module consists on the development of efficient energy scavenging systems. First, we have identified an innovative and relatively young technology, which can address at the same time two of the main concerns of human kind: water and energy. Microbial fuel cells (MFC) are capable of producing energy out the metabolism of bacteria while treating wastewater. We have developed two micro-liter MFC designs, one with carbon

The steam generator repair project of the Donald C. Cook Nuclear Plant, Unit 2

International Nuclear Information System (INIS)

White, J.D.

1993-01-01

Donald C. Cook Nuclear Plant Unit 2 is part of a two unit nuclear complex located in southwestern Michigan and owned and operated by the Indiana Michigan Power Company. The Cook Nuclear Plant is a pressurized water reactor (PWR) plant with four Westinghouse Series 51 steam generators housed in an ice condenser containment. This paper describes the program undertaken by Indiana Michigan Power and the American Electric Power Service Corporation (AEPSC) to repair the Unit 2 steam generators. (Both Indiana Michigan Power and AEPSC arc subsidiaries of American Electric Power Company, Incorporated (AEP). AEPSC provides management and technical support services to Indiana Michigan Power and the other AEP operating companies.) Eddy current examinations, in a series of refueling and forced outages between November 1983 and July 1986 resulted in 763 (5.6%) plugged tubes. In order to maintain adequate reactor core cooling, a limit of 10% is placed on the allowable percentage of steam generator tubes that can be removed from service by plugging. Additionally, sections of tubes were removed for metallurgical analysis and confirmed that the degradation was due to intergranular stress corrosion cracking. In developing the decision on how to repair the steam generators, four alternative actions were considered for addressing these problems: retubing in place, sleeving, operating at 80% reactor power to lower temperature and thus reduce the rate of corrosion, replacing steam generator lower assemblies

Cross-connected onsite emergency A.C. power supplies for multi-unit nuclear power plant sites

International Nuclear Information System (INIS)

Martore, J.A.; Voss, J.D.; Duncil, B.

1987-01-01

Recently, utility management, both at the corporate and plant operations levels, have reinforced their commitment to assuring increased plant reliability and availability. One means of achieving this objective involves an effective preventive maintenance program with technical specifications which allow implementation of certain preventive maintenance without plant shutdown. To accomplish this, Southern California Edison Company (SCE) has proposed a design change for San Onofre nuclear generating station (SONGS) units 2 and 3 to permit on emergency diesel generator for one unit to perform as an available AC power source for both units. Technical specifications for SCE's SONGS units 2 and 3, as at most nuclear power plants, currently require plant shutdown should one of the two dedicated onsite emergency AC power sources (diesel generators) become inoperable for more than 72 hours. This duration hinders root cause failure analysis, tends to limit the flexibility of preventive maintenance and precludes plant operation in the event of component failure. Therefore, this proposed diesel generator cross-connect design change offers an innovative means for averting plant shutdown should a single diesel generator become inoperable for longer than 72 hours. (orig./GL)

A study of the public opinion concerning nuclear power generation in the United States

International Nuclear Information System (INIS)

Oiso, Shinichi

2008-01-01

In this study, I surveyed the outcome of opinion poll about people's attitude toward nuclear power and analysed their awareness of nuclear power generation in the United States. As a result, it was found that percentage of the people who have positive attitude toward nuclear power has been over 60% since 1998. This result corresponds to the fact that people's preference is tending more toward nuclear power generation which is called the nuclear power Renaissance in the United States. Furthermore, analysis of the outcome of the opinion poll in power stations site region was also conducted and it was found that attitude of the people in the site region was more positive than that of average level in the United States. (author)

Experience in lifetime extension of the first generation WWER-440 power units

International Nuclear Information System (INIS)

Medvedev, P.

2002-01-01

In connection with the expiration of the lifetime for the first generation WWER-440 reactors in Russian Federation (Novo Voronezh and Kola NPP), the legal procedures and Life Time Extension (LTE) Program are discussed. The LTE Program includes: development of regulation basis; economic efficiency studies; power unit modernization; power unit comprehensive examination and justification od equipment resource; in-dept safety assessment; operational license acquisition. As a result from the LTE Program the safety level of the unit 3 of the Novo Voronezh NPP is significantly increases, the operational period has been justified and a 5-year license has been issued

Nuclear power generation costs in the United States of America

International Nuclear Information System (INIS)

Willis, W.F.

1983-01-01

Increasing world energy prices and shortages of fuel resources make the utilization of nuclear power extremely important. The United States nuclear power industry represents the largest body of nuclear power experience in the world. Analysis of the recent United States experience of substantial increases in the cost of nuclear power generation provides good insight into the interdependence of technological, financial, and institutional influences and their combined impact on the economic viability of nuclear power generation. The various factors influencing ultimate generation costs, including construction cost, fuel cost, regulatory reviews, and siting considerations are discussed, and their relative impacts are explored, including discussion of design complexity and related regulatory response. A closer look into the recent relatively high escalation of nuclear plant construction costs shows how differing economic conditions can affect the relative cost effectiveness of various methods of power generation. The vulnerability of capital-intensive, long-lead-time projects to changes in economic conditions and uncertainty in future power demands is discussed. Likewise, the pitfalls of new designs and increased sophistication are contrasted to the advantages which result from proven designs, reliable engineering, and shorter lead times. The value of reliable architect-engineers experienced in the design and construction of the plant is discussed. A discussion is presented of additional regulatory requirements stemming from public safety aspects of nuclear power. These include recognition of requirements for the very large effort for quality assurance of materials and workmanship during plant construction and operation. Likewise, a discussion is included of the demanding nature of operations, maintenance, and modification of plants during the operational phase because of the need for highly qualified operations and maintenance personnel and strict quality assurance

Effect of flexibility on flapping wing characteristics under forward flight

International Nuclear Information System (INIS)

Zhu, Jianyang; Jiang, Lin; Zhou, Chaoying; Wang, Chao

2014-01-01

Through two-dimensional numerical simulation and by solving the unsteady incompressible Navier–Stokes (NS) equations, coupled with the structural dynamic equation for the motion of the wing, the effect of flexibility on flapping wing characteristics during forward flight is systematically studied. The flapping wing is considered as a cantilever, which performs the translational and rotational motion at its leading edge, and the other part is passively deformed by the aerodynamic force. The frequency ratio ω* and mass ratio m* are defined and used to characterize the flexibility of the flapping wing. It has been found that an optimal range of the frequency ratio exists in which the flexible wing possesses both a larger propulsive efficiency and lifting efficiency than their rigid counterpart. Also, the flexible wing with the smaller mass ratio may be of benefit to generate thrust, while the larger mass ratio may be of benefit to generate lift. In addition, a stronger leading edge vortex and reattachment vortex are observed around the appropriate flexibility wing’s surface, which therefore leads to better aerodynamic characteristics. (paper)

Investigations of the unit generation costs of the nuclear power plants

International Nuclear Information System (INIS)

Guntay, S.

1977-01-01

An extensive study has been carried out to investigate the unit generation costs of different reactor types. The study analyzes the following: i) development of capital costs, ii) Fuel cycle costs, iii) operation and maintenance costs, iv) local and foreign finance requirements for an arbitrary reactor type

Characterization and dissolution studies of Bruce Unit 3 steam generator secondary side deposits

International Nuclear Information System (INIS)

Semmler, J.

1998-01-01

The physical and chemical properties of secondary side steam generator deposits in the form of powder and flake obtained from Bruce Nuclear Generating Station A (BNGS A) Unit 3 were studied. The chemical phases present in both types of deposits, collected prior to the 1994 chemical cleaning during the pre-clean water lancing campaign, were magnetite (Fe 3 O 4 ), metallic copper (Cu), hematite (Fe 2 O 3 ) and cuprous oxide (Cu 2 O). The major difference between the chemical composition of the powder and the flake was the presence of zinc silicate (Zn 2 SiO 4 ) and several unidentified silicate phases containing Ca, Al, Mn, and Mg in the flake. The flake deposit had high hardness values, high electrical resistivity, low porosity and a lower dissolution rate in the EPRI-SGOG (Electric Power Research Institute-Steam Generator Owner's Group) chemical cleaning solvents compared to the powder deposit. Differences in the deposit properties after chemical cleaning of the Unit 3 steam generators and after laboratory cleaning were noted. The presence of silicates in the deposit inhibit magnetite dissolution

Hydrodynamics of a flexible plate between pitching rigid plates

Science.gov (United States)

Kim, Junyoung; Kim, Daegyoum

2017-11-01

The dynamics of a flexible plate have been studied as a model problem in swimming and flying of animals and fluid-structure interaction of plants and flags. Motivated by fish schooling and an array of sea grasses, we investigate the dynamics of a flexible plate closely placed between two pitching rigid plates. In most studies on passive deformation of the flexible plate, the plate is immersed in a uniform flow or a wavy flow. However, in this study, the flexible plate experiences periodic deformation by the oscillatory flow generated by the prescribed pitching motion of the rigid plates. In our model, the pitching axes of the rigid plates and the clamping position of the flexible plate are aligned on the same line. The flexible plate shows various responses depending on length and pitching frequency of rigid plates, thickness of a flexible plate, and free-stream velocity. To find the effect of each variable on the response of the flexible plate, amplitude of a trailing edge and modal contribution of a flapping motion are compared, and flow structure around the flexible plate is examined.

Easy and flexible mixture distributions

DEFF Research Database (Denmark)

Fosgerau, Mogens; Mabit, Stefan L.

2013-01-01

We propose a method to generate flexible mixture distributions that are useful for estimating models such as the mixed logit model using simulation. The method is easy to implement, yet it can approximate essentially any mixture distribution. We test it with good results in a simulation study...

Column Generation for Transmission Switching of Electricity Networks with Unit Commitment

DEFF Research Database (Denmark)

Villumsen, Jonas Christoffer; Philpott, Andy B.

2011-01-01

This paper presents the problem of finding the minimum cost dispatch and commitment of power generation units in a transmission network with active switching.We use the term active switching to denote the use of switches to optimize network topology in an operational context. We propose a Dantzig...

Wearable and flexible electronics for continuous molecular monitoring.

Science.gov (United States)

Yang, Yiran; Gao, Wei

2018-04-03

Wearable biosensors have received tremendous attention over the past decade owing to their great potential in predictive analytics and treatment toward personalized medicine. Flexible electronics could serve as an ideal platform for personalized wearable devices because of their unique properties such as light weight, low cost, high flexibility and great conformability. Unlike most reported flexible sensors that mainly track physical activities and vital signs, the new generation of wearable and flexible chemical sensors enables real-time, continuous and fast detection of accessible biomarkers from the human body, and allows for the collection of large-scale information about the individual's dynamic health status at the molecular level. In this article, we review and highlight recent advances in wearable and flexible sensors toward continuous and non-invasive molecular analysis in sweat, tears, saliva, interstitial fluid, blood, wound exudate as well as exhaled breath. The flexible platforms, sensing mechanisms, and device and system configurations employed for continuous monitoring are summarized. We also discuss the key challenges and opportunities of the wearable and flexible chemical sensors that lie ahead.

Thin Flexible IMM Solar Array, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Thin, flexible, and highly efficient solar arrays are needed that package compactly for launch and deploy into large, structurally stable high power generators....

Generation of reservoir models on flexible meshes; Generation de modeles de reservoir sur maillage flexible

Energy Technology Data Exchange (ETDEWEB)

Ricard, L.

2005-12-15

The high level geo-statistic description of the subsurface are often far too detailed for use in routine flow simulators. To make flow simulations tractable, the number of grid blocks has to be reduced: an approximation, still relevant with flow description, is necessary. In this work, we place the emphasis on the scaling procedure from the fine scale model to the multi-scale reservoir model. Two main problems appear: Near wells, faults and channels, the volume of flexible cells may be less than fine ones, so we need to solve a down-scaling problem; Far from these regions, the volume of cells are bigger than fine ones so we need to solve an up-scaling problem. In this work, research has been done on each of these three areas: down-scaling, up-scaling and fluid flow simulation. For each of these subjects, a review, some news improvements and comparative study are proposed. The proposed down-scaling method is build to be compatible with existing data integration methods. The comparative study shows that empirical methods are not enough accurate to solve the problem. Concerning the up-scaling step, the proposed approach is based on an existing method: the perturbed boundary conditions. An extension to unstructured mesh is developed for the inter-cell permeability tensor. The comparative study shows that numerical methods are not always as accurate as expected and the empirical model can be sufficient in lot of cases. A new approach to single-phase fluid flow simulation is developed. This approach can handle with full tensorial permeability fields with source or sink terms.(author)

75 FR 34445 - Audit Program for Texas Flexible Permit Holders

Science.gov (United States)

2010-06-17

... flexible permit. The third-party auditor would identify for each emission unit regulated under the source's... Technology, State Implementation Plan citation). The auditor will also need to review and assess the adequacy... unit-specific emission limitations. Where deficiencies exist, the auditor will provide recommendations...

Replacement of steam generators at arkansas nuclear one, unit-2 (ano-2)

International Nuclear Information System (INIS)

Wilson, R.M.; Buford, A.

2001-01-01

The Arkansas Nuclear One, Unit-2 steam generators, originally supplied by Combustion Engineering, began commercial operation in 1980 producing a gross electrical output of 958 MW. After several years of successful operation, the owner decided that the tube degradation rates of the original steam generators were too high for the plant to meet the performance requirements for the full 40-year license period. The contract to supply replacement steam generators (RSGs) was awarded to Westinghouse Electric Company in 1996. Installation of these RSGs took place in the last months of 2000. This paper compares the design features of the original and re-placement steam generators with emphasis on design and reliability enhancements achieved. (author)

Towards a new generation of mission planning systems: Flexibility and performance

Science.gov (United States)

Gasquet, A.; Parrod, Y.; Desaintvincent, A.

1994-01-01

This paper presents some new approaches which are required for a better adequacy of Mission Planning Systems. In particular, the performance flexibility and genericity issues are discussed based on experience acquired through various Mission Planning systems developed by Matra Marconi Space.

Diagnostic testing and repair of Hollingsworth Generating Station`s Unit One

Energy Technology Data Exchange (ETDEWEB)

Atkins, R.; Epple, W.; Stevenson, D. [Great Lakes Power Ltd., Sault Ste. Marie, ON (Canada); Brotherton, L.; Crahan, M.; Ghate, A.

1995-12-31

A case history of the diagnosis and corrections implemented to resolve vibration problems in a 22,222 kVA hydroelectric generator was presented. The problem prevented the utility from operating the unit throughout the range of its nameplate rating and caused periodic failures of the generator`s guide and thrust bearing. Tests identified that the rim assembly was fastened onto the spider in a manner that resulted in tilting of the rim with respect to the axis of rotation, consequently, there was an unbalanced generator static air gap. A unique repair was implemented to fully restore the rim assembly to its proper position. Problems associated with carrying out such major in-situ repairs in a remote environment and within a scheduled maintenance outage were discussed. Economic benefits and costs associated with the repair were also discussed.

Simulation of a flexible wind turbine response to a grid fault

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Cutululis, Nicolaos Antonio; Sørensen, Poul Ejnar

2007-01-01

The purpose of this work is to illustrate the impact of a grid fault on the mechanical loads of a wind turbine. Grid faults generate transients in the generator electromagnetic torque, which are propagated in the wind turbine, stressing its mechanical components. Grid faults are normally simulated...... in power system simulation tools applying simplified mechanical models of the drive train. This paper presents simulations of the wind turbine load response to grid faults with an advanced aeroelastic computer code (HAWC2). The core of this code is an advanced model for the flexible structure of the wind...... turbines, taking the flexibility of the tower, blades and other components of the wind turbines into account. The effect of a grid fault on the wind turbine flexible structure is assessed for a typical fixed speed wind turbine, equipped with an induction generator....

The optimal scheduling of decentralised co-generation plants in microgrids; Optimale Einsatzplanung von Kraft-Waerme-Kopplungsanlagen in Microgrids

Energy Technology Data Exchange (ETDEWEB)

Gunkel, David [TU Dresden (Germany). Lehrstuhl fuer Energiewirtschaft; Hess, Tobias; Schegner, Peter [TU Dresden (Germany). Inst. fuer Elektrische Energieversorgung und Hochspannungstechnik

2011-07-01

The daily operational scheduling of decentralised unit is an important optimization task of power systems. This proceeding deals with planning of small scaled co-generation power units for district heating in a microgrid. This power system can be mathematically formulated and solved by an optimization algorithm. The solution process consists of a unit commitment and dispatch. The starting unit commitment is characterised by a mixed integer nonlinear problem defining the on-off-state of all units. Subsequently, the dispatch distributes the generation requirements to every committed unit considering thermal demand. The dispatching is based on a mixed integer linear problem. Additionally, it presents a way for flexible reducing the outage reserve related to the operational condition. The given microgrid operates in an islanding mode. The method can also be applied in a grid connected model considering the possible requirements of a grid operator. (orig.)

Design of a Facility to Test the Advanced Stirling Radioisotope Generator Engineering Unit

Science.gov (United States)

Lewandowski, Edward J.; Schreiber, Jeffrey G.; Oriti, Salvatore M.; Meer, David W.; Brace, Michael H.; Dugala, Gina

2009-01-01

The Advanced Stirling Radioisotope Generator (ASRG) is being considered to power deep space missions. An engineering unit, the ASRG-EU, was designed and fabricated by Lockheed Martin under contract to the Department of Energy. This unit is currently on an extended operation test at NASA Glenn Research Center to generate performance data and validate the life and reliability predictions for the generator and the Stirling convertors. A special test facility was designed and built for testing the ASRG-EU. Details of the test facility design are discussed. The facility can operate the convertors under AC bus control or with the ASRG-EU controller. It can regulate input thermal power in either a fixed temperature or fixed power mode. An enclosure circulates cooled air around the ASRG-EU to remove heat rejected from the ASRG-EU by convection. A custom monitoring and data acquisition system supports the test. Various safety features, which allow 2417 unattended operation, are discussed.

Pseudo-random number generators for Monte Carlo simulations on ATI Graphics Processing Units

Science.gov (United States)

Demchik, Vadim

2011-03-01

Basic uniform pseudo-random number generators are implemented on ATI Graphics Processing Units (GPU). The performance results of the realized generators (multiplicative linear congruential (GGL), XOR-shift (XOR128), RANECU, RANMAR, RANLUX and Mersenne Twister (MT19937)) on CPU and GPU are discussed. The obtained speed up factor is hundreds of times in comparison with CPU. RANLUX generator is found to be the most appropriate for using on GPU in Monte Carlo simulations. The brief review of the pseudo-random number generators used in modern software packages for Monte Carlo simulations in high-energy physics is presented.

Strategic bidding of generating units in competitive electricity market with considering their reliability

International Nuclear Information System (INIS)

Soleymani, S.; Ranjbar, A.M.; Shirani, A.R.

2008-01-01

In the restructured power systems, they are typically scheduled based on the offers and bids to buy and sell energy and ancillary services (AS) subject to operational and security constraints. Generally, no account is taken of unit reliability when scheduling it. Therefore generating units have no incentive to improve their reliability. This paper proposes a new method to obtain the equilibrium points for reliability and price bidding strategy of units when the unit reliability is considered in the scheduling problem. The proposed methodology employs the supply function equilibrium (SFE) for modeling a unit's bidding strategy. Units change their bidding strategies and improve their reliability until Nash equilibrium points are obtained. GAMS (general algebraic modeling system) language has been used to solve the market scheduling problem using DICOPT optimization software with mixed integer non-linear programming. (author)

Making Professional Development Flexible: A Case Study.

Science.gov (United States)

Forsyth, Rachel

2002-01-01

Presents a case study of an online course that was designed for staff professional development at Manchester Metropolitan University (United Kingdom). Discusses the flexibility of online courses; course design; activities for short online workshops; evaluation methods for course evaluation; and results of participant questionnaires. (LRW)

Tube structural integrity evaluation of Palo Verde Unit 1 steam generators for axial upper-bundle cracking

International Nuclear Information System (INIS)

Woodman, B.W.; Begley, J.A.; Brown, S.D.; Sweeney, K.; Radspinner, M.; Melton, M.

1995-01-01

The analysis of the issue of upper bundle axial ODSCC as it apples to steam generator tube structural integrity in Unit 1 at the Palo Verde Nuclear generating Station is presented in this study. Based on past inspection results for Units 2 and 3 at Palo Verde, the detection of secondary side stress corrosion cracks in the upper bundle region of Unit 1 may occur at some future date. The following discussion provides a description and analysis of the probability of axial ODSCC in Unit 1 leading to the exceedance of Regulatory Guide 1.121 structural limits. The probabilities of structural limit exceedance are estimated as function of run time using a conservative approach. The chosen approach models the historical development of cracks, crack growth, detection of cracks and subsequent removal from service and the initiation and growth of new cracks during a given cycle of operation. Past performance of all Palo Verde Units as well as the historical performance of other steam generators was considered in the development of cracking statistics for application to Unit 1. Data in the literature and Unit 2 pulled tube examination results were used to construct probability of detection curves for the detection of axial IGSCC/IGA using an MRPC (multi-frequency rotating panake coil) eddy current probe. Crack growth rates were estimated from Unit 2 eddy current inspection data combined with pulled tube examination results and data in the literature. A Monte-Carlo probabilistic model is developed to provide an overall assessment of the risk of Regulatory Guide exceedance during plant operation

An introduction to the installation of Unit 5 at Revelstoke Generating Station

International Nuclear Information System (INIS)

1994-07-01

The Revelstoke hydroelectric power plant in British Columbia has four generating units with a total capacity of 1843 MW. The plant was designed as a six-unit facility, with space provided in the powerhouse for two additional units in Bays 5 and 6. It is proposed to install a fifth unit at Revelstoke, which will increase capacity by ca 460 MW. No additional land or transmission facilities will be required for this project, whose estimated direct construction cost is $90 million. The new unit is felt to be needed because of anticipated capacity shortfalls that could occur on the British Columbia Hydro system as early as 1996 or as late as 2004. Preliminary engineering and environmental studies are reviewed, and the public consultation program and procurement plan for the project are outlined. Potential impacts on land use and heritage resources appear negligible, and recreation use of Revelstoke Reservoir is not expected to be significantly impacted. Changes in reservoir fluctuations with Unit 5 in place will be minimal. 4 figs

Feasibility Analysis of Liquefying Oxygen Generated from Water Electrolysis Units on Lunar Surface

Science.gov (United States)

Jeng, Frank F.

2009-01-01

Concepts for liquefying oxygen (O2) generated from water electrolysis subsystems on the Lunar surface were explored. Concepts for O2 liquefaction units capable of generating 1.38 lb/hr (0.63 kg/hr) liquid oxygen (LOX) were developed. Heat and mass balance calculations for the liquefaction concepts were conducted. Stream properties, duties of radiators, heat exchangers and compressors for the selected concepts were calculated and compared.

Exploration of dispatch model integrating wind generators and electric vehicles

International Nuclear Information System (INIS)

Haque, A.N.M.M.; Ibn Saif, A.U.N.; Nguyen, P.H.; Torbaghan, S.S.

2016-01-01

Highlights: • A novel business model for the BRPs is analyzed. • Imbalance cost of wind generation is considered in the UC-ED model. • Smart charging of EVs is included into the UC-ED problem to mitigate the imbalance cost. • Effects of smart charging on generation cost, CO 2 emissions and total network load are assessed. - Abstract: In recent years, the share of renewable energy sources (RES) in the electricity generation mix has been expanding rapidly. However, limited predictability of the RES poses challenges for traditional scheduling and dispatching mechanisms based on unit commitment (UC) and economic dispatch (ED). This paper presents an advanced UC-ED model to incorporate wind generators as RES-based units alongside conventional centralized generators. In the proposed UC-ED model, an imbalance cost is introduced reflecting the wind generation uncertainty along with the marginal generation cost. The proposed UC-ED model aims to utilize the flexibility of fleets of plug-in electric vehicles (PEVs) to optimally compensate for the wind generation uncertainty. A case study with 15 conventional units and 3 wind farms along with a fixed-sized PEV fleet demonstrates that shifting of PEV fleets charging at times of high wind availability realizes generation cost savings. Nevertheless, the operational cost saving incurred by controlled charging appears to diminish when dispatched wind energy becomes considerably larger than the charging energy of PEV fleets. Further analysis of the results reveals that the effectiveness of PEV control strategy in terms of CO 2 emission reduction is strongly coupled with generation mix and the proposed control strategy is favored in cases where less pollutant-based plants like nuclear and hydro power are profoundly dominant.

Aggregation of demand side flexibility in a smart grid: A review for European market design

OpenAIRE

Eid , Cherrelle; Codani , Paul; Chen , Yurong; Perez , Yannick; Hakvoort , Rudi

2015-01-01

International audience; The increased share of renewable generation and the integration of Distributed Generation (DG) require more electricity system flexibility. One way to increase this flexibility is to use the potentials of demand response (DR). In order to activate the full range of customers in DR, a new market intermediary actor is needed to aggregate the resources in an adequate technical and economical format. These actors, so called " aggregators " , can act as flexibility provider...

Flexibility dynamics in clusters of residential demand response and distributed generation

NARCIS (Netherlands)

MacDougall, P.A.; Kok, J.K.; Warmer, C.; Roossien, B.

2013-01-01

Supply and demand response is a untapped resource in the current electrical system. However little work has been done to investigate the dynamics of utilizing such flexibility as well as the potential effects it could have on the infrastructure. This paper provides a starting point to seeing the

Underwater thrust and power generation using flexible piezoelectric composites: an experimental investigation toward self-powered swimmer-sensor platforms

International Nuclear Information System (INIS)

Erturk, Alper; Delporte, Ghislain

2011-01-01

Fiber-based flexible piezoelectric composites offer several advantages to use in energy harvesting and biomimetic locomotion. These advantages include ease of application, high power density, effective bending actuation, silent operation over a range of frequencies, and light weight. Piezoelectric materials exhibit the well-known direct and converse piezoelectric effects. The direct piezoelectric effect has received growing attention for low-power generation to use in wireless electronic applications while the converse piezoelectric effect constitutes an alternative to replace the conventional actuators used in biomimetic locomotion. In this paper, underwater thrust and electricity generation are investigated experimentally by focusing on biomimetic structures with macro-fiber composite piezoelectrics. Fish-like bimorph configurations with and without a passive caudal fin (tail) are fabricated and compared. The favorable effect of having a passive caudal fin on the frequency bandwidth is reported. The presence of a passive caudal fin is observed to bring the second bending mode close to the first one, yielding a wideband behavior in thrust generation. The same smart fish configuration is tested for underwater piezoelectric power generation in response to harmonic excitation from its head. Resonant piezohydroelastic actuation is reported to generate milli-newton level hydrodynamic thrust using milli-watt level actuation power input. The average actuation power requirement for generating a mean thrust of 19 mN at 6 Hz using a 10 g piezoelastic fish with a caudal fin is measured as 120 mW. This work also discusses the feasibility of thrust generation using the harvested energy toward enabling self-powered swimmer-sensor platforms with comparisons based on the capacity levels of structural thin-film battery layers as well as harvested solar and vibrational energy

Multi-Functional Distributed Generation Unit for Power Quality Enhancement

DEFF Research Database (Denmark)

Zeng, Zheng; Yang, Huan; Guerrero, Josep M.

2015-01-01

A multi-functional distributed generation unit (MFDGU) and its control strategy are proposed in this paper for the purpose of enhancing power quality in low-voltage networks. By using the 3H-bridge converter structure, an MFDGU can be applied in 3-phase 4-wire low-voltage distribution networks...... reference of the MFDGU, which can be easily implemented in three-phase networks. A 15kVA prototype consisting of three full bridge converters has been built and tested. Experimental results show the feasibility of the proposed topology and control strategy....

Flexibility in Europe's power sector — An additional requirement or an automatic complement?

International Nuclear Information System (INIS)

Bertsch, Joachim; Growitsch, Christian; Lorenczik, Stefan; Nagl, Stephan

2016-01-01

By 2050, the European Union aims to reduce greenhouse gases by more than 80%. The EU member states have therefore declared to strongly increase the share of renewable energy sources (RES-E) in the next decades. Given a large deployment of wind and solar capacities, there are two major impacts on electricity systems: First, the electricity system must be flexible enough to cope with the volatile RES-E generation, i.e., ramp up supply or ramp down demand on short notice. Second, sufficient back-up capacities are needed during times with low feed-in from wind and solar capacities. This paper analyzes whether there is a need for additional incentive mechanisms for flexibility in electricity markets with a high share of renewables. For this purpose, we simulate the development of the European electricity markets up to the year 2050 using a linear investment and dispatch optimization model. Flexibility requirements are implemented in the model via ramping constraints and provision of balancing power. We found that an increase in fluctuating renewables has a tremendous impact on the volatility of the residual load and consequently on the flexibility requirements. However, any market design that incentivizes investments in least (total system) cost generation investment does not need additional incentives for flexibility. The main trigger for investing in flexible resources is the achievable full load hours and the need for backup capacity. In a competitive market, the cost-efficient technologies that are most likely to be installed, i.e., gas-fired power plants or flexible CCS plants, provide flexibility as a by-product. Under the condition of system adequacy, flexibility never poses a challenge in a cost-minimal capacity mix. Therefore, any market design incentivizing investments in efficient generation thus provides flexibility as an inevi complement. - Highlights: • We analyze flexibility in electricity systems with a high share of renewables. • For scenario

Sliding Mode Control of a Slewing Flexible Beam

Science.gov (United States)

Wilson, David G.; Parker, Gordon G.; Starr, Gregory P.; Robinett, Rush D., III

1997-01-01

An output feedback sliding mode controller (SMC) is proposed to minimize the effects of vibrations of slewing flexible manipulators. A spline trajectory is used to generate ideal position and velocity commands. Constrained nonlinear optimization techniques are used to both calibrate nonlinear models and determine optimized gains to produce a rest-to-rest, residual vibration-free maneuver. Vibration-free maneuvers are important for current and future NASA space missions. This study required the development of the nonlinear dynamic system equations of motion; robust control law design; numerical implementation; system identification; and verification using the Sandia National Laboratories flexible robot testbed. Results are shown for a slewing flexible beam.

Design and implementation of flexible TWDM-PON with PtP WDM overlay based on WSS for next-generation optical access networks

Science.gov (United States)

Wu, Bin; Yin, Hongxi; Qin, Jie; Liu, Chang; Liu, Anliang; Shao, Qi; Xu, Xiaoguang

2016-09-01

Aiming at the increasing demand of the diversification services and flexible bandwidth allocation of the future access networks, a flexible passive optical network (PON) scheme combining time and wavelength division multiplexing (TWDM) with point-to-point wavelength division multiplexing (PtP WDM) overlay is proposed for the next-generation optical access networks in this paper. A novel software-defined optical distribution network (ODN) structure is designed based on wavelength selective switches (WSS), which can implement wavelength and bandwidth dynamical allocations and suits for the bursty traffic. The experimental results reveal that the TWDM-PON can provide 40 Gb/s downstream and 10 Gb/s upstream data transmission, while the PtP WDM-PON can support 10 GHz point-to-point dedicated bandwidth as the overlay complement system. The wavelengths of the TWDM-PON and PtP WDM-PON are allocated dynamically based on WSS, which verifies the feasibility of the proposed structure.

Flexibility.

Science.gov (United States)

Humphrey, L. Dennis

1981-01-01

Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

Santee Cooper cross units 3 & 4: an EPCM success

Energy Technology Data Exchange (ETDEWEB)

Hickson, K.; Neher, S.; Koontz, N. [WorleyParons (United States)

2009-05-15

In late 2001, Santee Cooper began a project to add a third 600 MW unit to its coal-fired Cross Generating Station in Cross, S.C. Plans also included a fourth unit to be added later. The engineering, procurement and construction (EPCM) of Units 3 and 4 would eventually span almost seven years. The Cross Project demonstrates how Santee Cooper empowered its EPCM contractor to manage for change and how a well conceived plan and thoroughly developed schedule provide the necessary structure and flexibility to successful do so. The Cross Project experience reinforces the idea that for large projects an EPCM arrangement provides the agility necessary to manage change and the means to manage risk. The design, furnish and erect contracts were performance based contracts executed early to firm up the plant design and layout. 2 photos.

Main problems experienced on diesel generators of French 900 MWe operating units

Energy Technology Data Exchange (ETDEWEB)

Dredemis, Geoffroy; Jude, Francois [Commissariat a l' Energie Atomique, centre d' Etudes Nucleaires de Fontenay-aux-Roses, Institut de Protection et Surete Nucleaire, Departement d' Analyse de Surete, B.P. No. 6, 92260 Fontenay-aux-Roses (France)

1986-02-15

Each unit of all the French nuclear power plant is equipped with two diesel emergency generator sets., For the totality of standards PWRs of 900 MWe, they are identical. We present in this communication the most significative failures met with diesel engines on operating units, such as rupture of fuel injection pipes, breaking of the connecting rods, and cylinder lubrication failures. All these incidents, which affected the emergency power sources of concerned units, had generic characteristics. In view of their potential consequences, it was proceeded in each case to an immediate control of the components concerned of all PWR 900 MWe diesel engines. At the same time, studies were started as to what modifications would permit to solve rapidly each one of the problems met with. (authors)

Emissions implications of downscaled electricity generation scenarios for the western United States

Energy Technology Data Exchange (ETDEWEB)

Nsanzineza, Rene; O’Connell, Matthew; Brinkman, Gregory; Milford, Jana B.

2017-10-01

This study explores how emissions from electricity generation in the Western Interconnection region of the U.S. might respond in circa 2030 to contrasting scenarios for fuel prices and greenhouse gas (GHG) emissions fees. We examine spatial and temporal variations in generation mix across the region and year using the PLEXOS unit commitment and dispatch model with a production cost model database adapted from the Western Electricity Coordinating Council. Emissions estimates are computed by combining the dispatch model results with unit-specific, emissions-load relationships. Wind energy displaces natural gas and coal in scenarios with relatively expensive natural gas or with GHG fees. Correspondingly, annual emissions of NOx, SO2, and CO2 are reduced by 20-40% in these cases. NOx emissions, which are a concern as a precursor of ground-level ozone, are relatively high and consistent across scenarios during summer, when peak electricity loads occur and wind resources in the region are comparatively weak. Accounting for the difference in start-up versus stabilized NOx emissions rates for natural gas plants had little impact on region-wide emissions estimates due to the dominant contribution from coal-fired plants, but would be more important in the vicinity of the natural gas units.

75 FR 52045 - Arizona Public Service Company, Palo Verde Nuclear Generating Station, Unit 3; Environmental...

Science.gov (United States)

2010-08-24

... Company, Palo Verde Nuclear Generating Station, Unit 3; Environmental Assessment and Finding of No.... NPF-74, issued to Arizona Public Service Company (APS, the licensee), for operation of Palo Verde... Statement for the Palo Verde Nuclear Generating Station, NUREG-0841, dated February 1982. Agencies and...

Intense generation of respirable metal nanoparticles from a low-power soldering unit

Energy Technology Data Exchange (ETDEWEB)

Gómez, Virginia [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Irusta, Silvia [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain); Balas, Francisco [Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain); Instituto de Carboquímica – Consejo Superior de Investigaciones Científicas (ICB-CSIC), 50018 Zaragoza (Spain); Santamaria, Jesus, E-mail: Jesus.Santamaria@unizar.es [Department of Chemical Engineering, Nanoscience Institute of Aragon (INA), 50018 Zaragoza (Spain); Networking Biomedical Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 50018 Zaragoza (Spain)

2013-07-15

Highlights: • Intense generation of nanoparticles in the breathing range from a flux-soldering unit is detected. • Coagulation in the aerosol phase leads to 200-nm respirable nanoparticles up to 30 min after operation. • Nanoparticle concentration in the working environment depends on the presence of ambient air. • Metal-containing nanoparticles are collected in TEM grids and filters in the hundreds of nanometer range. -- Abstract: Evidence of intense nanoparticle generation from a low power (45 W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 10{sup 6} particles/cm{sup 3}) within the breathing range of the operator, with initial size distributions centered at 35–60 nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals.

Intense generation of respirable metal nanoparticles from a low-power soldering unit

International Nuclear Information System (INIS)

Gómez, Virginia; Irusta, Silvia; Balas, Francisco; Santamaria, Jesus

2013-01-01

Highlights: • Intense generation of nanoparticles in the breathing range from a flux-soldering unit is detected. • Coagulation in the aerosol phase leads to 200-nm respirable nanoparticles up to 30 min after operation. • Nanoparticle concentration in the working environment depends on the presence of ambient air. • Metal-containing nanoparticles are collected in TEM grids and filters in the hundreds of nanometer range. -- Abstract: Evidence of intense nanoparticle generation from a low power (45 W) flux soldering unit is presented. This is a familiar device often used in daily life, including home repairs and school electronic laboratories. We demonstrate that metal-containing nanoparticles may reach high concentrations (ca. 10 6 particles/cm 3 ) within the breathing range of the operator, with initial size distributions centered at 35–60 nm The morphological and chemical analysis of nanoparticle agglomerates collected on TEM grids and filters confirms their multiparticle structure and the presence of metals

Flexibility as a management principle in dementia care: the Adards example.

Science.gov (United States)

Cohen-Mansfield, Jiska; Bester, Allan

2006-08-01

Flexibility is an essential ingredient of person-centered care. We illustrate the potential impact of flexibility by portraying a nursing home that uses flexibility in its approach to residents and staff members. The paper describes the management strategies, principles, and environmental features used by the Adards nursing home in Australia. Adards' flexibility in daily work and task scheduling promotes both resident and staff autonomy, which in turn allows for higher staffing levels, lower staff turnover, and more typical life experiences for residents than is found in many long-term-care facilities in the United States. The article provides an example and a basis for future discussion on this topic, with the hope that it will prompt other institutions to expand the level of flexibility in their policies and procedures.

Highly efficient tandem organic light-emitting devices employing an easily fabricated charge generation unit

Science.gov (United States)

Yang, Huishan; Yu, Yaoyao; Wu, Lishuang; Qu, Biao; Lin, Wenyan; Yu, Ye; Wu, Zhijun; Xie, Wenfa

2018-02-01

We have realized highly efficient tandem organic light-emitting devices (OLEDs) employing an easily fabricated charge generation unit (CGU) combining 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of CsN3 and Al. The charge generation and separation processes of the CGU have been demonstrated by studying the differences in the current density-voltage characteristics of external-carrier-excluding devices. At high luminances of 1000 and 10000 cd/m2, the current efficiencies of the phosphorescent tandem device are about 2.2- and 2.3-fold those of the corresponding single-unit device, respectively. Simultaneously, an efficient tandem white OLED exhibiting high color stability and warm white emission has also been fabricated.

Advanced methodology for generation expansion planning including interconnected systems

Energy Technology Data Exchange (ETDEWEB)

Zhao, M; Yokoyama, R; Yasuda, K [Tokyo Metropolitan Univ. (Japan); Sasaki, H [Hiroshima Univ. (Japan); Ogimoto, K [Electric Power Development Co. Ltd., Tokyo (Japan)

1994-12-31

This paper reviews advanced methodology for generation expansion planning including interconnected systems developed in Japan, putting focus on flexibility and efficiency in a practical application. First, criteria for evaluating flexibility of generation planning considering uncertainties are introduced. Secondly, the flexible generation mix problem is formulated as a multi-objective optimization with more than two objective functions. The multi-objective optimization problem is then transformed into a single objective problem by using the weighting method, to obtain the Pareto optimal solution, and solved by a dynamics programming technique. Thirdly, a new approach for electric generation expansion planning of interconnected systems is presented, based on the Benders Decomposition technique. That is, large scale generation problem constituted by the general economic load dispatch problem, and several sub problems which are composed of smaller scale isolated system generation expansion plans. Finally, the generation expansion plan solved by an artificial neural network is presented. In conclusion, the advantages and disadvantages of this method from the viewpoint of flexibility and applicability to practical generation expansion planning are presented. (author) 29 refs., 10 figs., 4 tabs.

Control technique for enhancing the stable operation of distributed generation units within a microgrid

International Nuclear Information System (INIS)

Mehrasa, Majid; Pouresmaeil, Edris; Mehrjerdi, Hasan; Jørgensen, Bo Nørregaard; Catalão, João P.S.

2015-01-01

Highlights: • A control technique for enhancing the stable operation of distributed generation units is proposed. • Passivity-based control technique is considered to analyze the dynamic and steady-state behaviors. • The compensation of instantaneous variations in the reference current components is considered. • Simulation results confirm the performance of the control scheme within the microgrid. - Abstract: This paper describes a control technique for enhancing the stable operation of distributed generation (DG) units based on renewable energy sources, during islanding and grid-connected modes. The Passivity-based control technique is considered to analyze the dynamic and steady-state behaviors of DG units during integration and power sharing with loads and/or power grid, which is an appropriate tool to analyze and define a stable operating condition for DG units in microgrid technology. The compensation of instantaneous variations in the reference current components of DG units in ac-side, and dc-link voltage variations in dc-side of interfaced converters, are considered properly in the control loop of DG units, which is the main contribution and novelty of this control technique over other control strategies. By using the proposed control technique, DG units can provide the continuous injection of active power from DG sources to the local loads and/or utility grid. Moreover, by setting appropriate reference current components in the control loop of DG units, reactive power and harmonic current components of loads can be supplied during the islanding and grid-connected modes with a fast dynamic response. Simulation results confirm the performance of the control scheme within the microgrid during dynamic and steady-state operating conditions

Multi-gigabit optical interconnects for next-generation on-board digital equipment

Science.gov (United States)

Venet, Norbert; Favaro, Henri; Sotom, Michel; Maignan, Michel; Berthon, Jacques

2017-11-01

Parallel optical interconnects are experimentally assessed as a technology that may offer the high-throughput data communication capabilities required to the next-generation on-board digital processing units. An optical backplane interconnect was breadboarded, on the basis of a digital transparent processor that provides flexible connectivity and variable bandwidth in telecom missions with multi-beam antenna coverage. The unit selected for the demonstration required that more than tens of Gbit/s be supported by the backplane. The demonstration made use of commercial parallel optical link modules at 850 nm wavelength, with 12 channels running at up to 2.5 Gbit/s. A flexible optical fibre circuit was developed so as to route board-to-board connections. It was plugged to the optical transmitter and receiver modules through 12-fibre MPO connectors. BER below 10-14 and optical link budgets in excess of 12 dB were measured, which would enable to integrate broadcasting. Integration of the optical backplane interconnect was successfully demonstrated by validating the overall digital processor functionality.

Geothermal power generation in the United States 1985 through 1989

International Nuclear Information System (INIS)

Rannels, J.E.; McLarty, L.

1990-01-01

The United States has used geothermal energy for the production of electricity since 1960 and has the largest installed capacity of any country in the world. During the 1980s, expansion at The Geysers and emergence of the hot water segment of the industry fueled explosive growth in generating capacity. In this paper geothermal development in the U.S. during the second half of the decade is reviewed, and development over the next five years is forecast

The Research of Utilization Hours of Coal-Fired Power Generation Units Based on Electric Energy Balance

Science.gov (United States)

Liu, Junhui; Yang, Jianlian; Wang, Jiangbo; Yang, Meng; Tian, Chunzheng; He, Xinhui

2018-01-01

With grid-connected scale of clean energy such as wind power and photovoltaic power expanding rapidly and cross-province transmission scale being bigger, utilization hours of coal-fired power generation units become lower and lower in the context of the current slowdown in electricity demand. This paper analyzes the influencing factors from the three aspects of demand, supply and supply and demand balance, and the mathematical model has been constructed based on the electric energy balance. The utilization hours of coal-fired power generation units have been solved considering the relationship among proportion of various types of power installed capacity, the output rate and utilization hours. By carrying out empirical research in Henan Province, the utilization hours of coal-fired units of Henan Province in 2020 has been achieved. The example validates the practicability and the rationality of the model, which can provide a basis for the decision-making for coal-fired power generation enterprises.

Investigating the Impact of Climate Change on Hydroelectric Generation and Ancillary Services in California

Science.gov (United States)

Forrest, K.; Tarroja, B.; AghaKouchak, A.; Chiang, F.; Samuelsen, S.

2017-12-01

Spatial and temporal shifts in hydrological regimes predicted under climate change conditions have implications for the management of reservoirs and hydropower contributions to generation and ancillary services. California relies on large hydropower plants to provide flexible electricity generation, which will be increasingly important for supporting renewable resources. This study examines the impact of climate change on large hydropower generation in California. Four climate models for Representative Concentration Pathways (RCP) 4.5 and RCP 8.5 are utilized to evaluate the impact of the climate change conditions on (1) the magnitude and profile of hydropower generation and (2) the ability of hydropower to provide spinning reserve. Under both RCP scenarios, impacts are regionally dependent, with precipitation projected to increase in northern California and decrease in southern California for the ten-year period investigated (2046-2055). The overall result is a net increase in inflow into large hydropower units as a majority of the hydropower plants studied are located in the northern part of the state. Increased inflow is primarily driven by increased runoff during the winter and does not necessarily result in increased generation, as extreme events yield greater overall spillage, up to 45% of total inflow. Increased winter hydropower generation paired with increased reservoir constraints in summer result in an 11 to 18% decrease in spinning reserve potential across the year. Under high inflow conditions there is a decreased flexibility for choosing generation versus spinning reserve as water needs to be released, regardless. During summer, hydropower units providing spinning reserve experienced decreased inflow and lower reservoir levels compared to the historical baseline, resulting in decreased spinning reserve bidding potential. Decreased bidding, especially during summer periods at peak electricity demand, can result in greater demand for other dispatchable

Flexible organic light emitting diodes fabricated on biocompatible silk fibroin substrate

International Nuclear Information System (INIS)

Liu, Yuqiang; Xie, Yuemin; Liu, Yuan; Song, Tao; Liao, Liangsheng; Sun, Baoquan; Zhang, Ke-Qin

2015-01-01

Flexible and biodegradable electronics are currently under extensive investigation for biocompatible and environmentally-friendly applications. Synthetic plastic foils are widely used as substrates for flexible electronics. But typical plastic substrates such as polyethylene naphthalate (PEN) could not be degraded in a natural bio-environment. A great demand still exists for a next-generation biocompatible and biodegradable substrate for future application. For example, electronic devices can be potentially integrated into the human body. In this work, we demonstrate that the biocompatible and biodegradable natural silk fibroin (SF) films embedded with silver nanowires (AgNWs) mesh could be employed as conductive transparent substrates to fabricate flexible organic light emitting diodes (OLEDs). Compared with commercial PEN substrates coated with indium tin oxide, the AgNWs/SF composite substrates exhibit a similar sheet resistance of 12 Ω sq −1 , a lower surface roughness, as well as a broader light transmission range. Flexible OLEDs based on AgNWs/SF substrates achieve a current efficiency of 19 cd A −1 , demonstrating the potential of the flexible AgNWs/SF films as conductive and transparent substrates for next-generation biodegradable devices. (paper)

Flexible organic light emitting diodes fabricated on biocompatible silk fibroin substrate

Science.gov (United States)

Liu, Yuqiang; Xie, Yuemin; Liu, Yuan; Song, Tao; Zhang, Ke-Qin; Liao, Liangsheng; Sun, Baoquan

2015-10-01

Flexible and biodegradable electronics are currently under extensive investigation for biocompatible and environmentally-friendly applications. Synthetic plastic foils are widely used as substrates for flexible electronics. But typical plastic substrates such as polyethylene naphthalate (PEN) could not be degraded in a natural bio-environment. A great demand still exists for a next-generation biocompatible and biodegradable substrate for future application. For example, electronic devices can be potentially integrated into the human body. In this work, we demonstrate that the biocompatible and biodegradable natural silk fibroin (SF) films embedded with silver nanowires (AgNWs) mesh could be employed as conductive transparent substrates to fabricate flexible organic light emitting diodes (OLEDs). Compared with commercial PEN substrates coated with indium tin oxide, the AgNWs/SF composite substrates exhibit a similar sheet resistance of 12 Ω sq-1, a lower surface roughness, as well as a broader light transmission range. Flexible OLEDs based on AgNWs/SF substrates achieve a current efficiency of 19 cd A-1, demonstrating the potential of the flexible AgNWs/SF films as conductive and transparent substrates for next-generation biodegradable devices.

Solar photovoltaic systems and their use as grid-connected generators in the United Kingdom

Energy Technology Data Exchange (ETDEWEB)

Munro, D K; Hacker, R J; Thornycroft, J M [Halcrow Gilbert Associates Ltd., Swindon (United Kingdom)

1995-10-01

There is an increasing interest in the use of building-integrated solar photovoltaic generators as grid-connected generators. This paper discusses the experience with this technology in Europe. Typical systems and their integration into domestic and non-domestic buildings are described. Information is provided on the energy output that can be expected from the systems and the economics of their use. The paper provides an overview of the requirements for photovoltaic systems as grid-connected generation plant in the United Kingdom. (Author)

Combined cycle design flexibility in today's market

International Nuclear Information System (INIS)

DeRidder, W.N.; Knott, S.J.

1995-01-01

In the power generation industry, non utility generators (NUG's) comprise a significant portion of new generation growth as electricity demands exceed existing utility capacities. These NUG's are developed by customers with widely varying experiences; bankers, lawyers, architect engineers, original equipment manufacturers, and other organizations involved in such diverse industries as petrochemical, pulp and paper, and steel making. The demands of these customers can be significantly varied in terms of features such as capacity factor, operability, maintainability, equipment redundancy, acceptable design practices, and many others. In addition, both the utility and NUG industries demand flexibility due to external influences such as regulatory policies, environmental conditions new design technologies, and emerging global markets. All of these factors are subject to wide variation across different market regions and even within a given region. This paper discusses the development of a reference plant design approach which focuses on customer flexibility while maximizing the use of proven designs. This approach allows basic system designs to be modified in a modular fashion to meet the differing demands of utility and NUG customers

Application of CFB technology for large power generating units and CO2 capture

International Nuclear Information System (INIS)

Ryabov, G. A.; Folomeev, O. M.; Sankin, D. A.; Khaneev, K. V.; Bondarenko, I. G.; Mel'nikov, D. A.

2010-01-01

Data on the development of the circulating fluidized bed (CFB) technology for combustion of fuels in large power generating units are examined. The problems with raising the steam parameters and unit power of boilers with a circulating fluidized bed are examined. With the boiler system at the 460 MW unit at Lagisza (Poland) as an example, the feasibility of raising the efficiency of units with CFB boilers through deep recovery of the heat of the effluent gases and reducing expenditure for in-house needs is demonstrated. Comparative estimates of the capital and operating costs of 225 and 330 MW units are used to determine the conditions for optimum use of CFB boilers in the engineering renovation of thermal power plants in Russia. New areas for the application of CFB technology in CO 2 capture are analyzed in connection with the problem of reducing greenhouse gas emissions.

Decoupled Multicamera Sensing for Flexible View Generation

Directory of Open Access Journals (Sweden)

Vivek K. Singh

2016-01-01

Full Text Available Any sensing paradigm has three important components, namely, the actor, the sensor, and the environment. Traditionally, the sensors have been attached to either the actor or the environment. This restricts the kind of sensing that can be undertaken. We study a newer decoupled sensing paradigm, which separates the sensors from both the actor and the environment and tremendously increases the flexibility with which the scenes can be viewed. For example, instead of showing just one view, “how the environment sees the actor” or “how the actor sees the environment,” a viewer can choose to see either one or both of these views and even choose to see the scene from any desired position in any desired direction. We describe a methodology using mobile autonomous sensors to undertake such decoupled sensing and study the feasible number as well as the placement of such sensors. Also, we describe how the sensors can coordinate their movements around a moving actor so as to continue capturing the required views with minimum overall cost. The practical results obtained demonstrate the viability of the proposed approach.

Regulatory road maps for the integration of intermittent electricity generation: Methodology development and the case of The Netherlands

International Nuclear Information System (INIS)

Welle, Adriaan J. van der; Joode, Jeroen de

2011-01-01

The envisaged increase in the share of electricity generation from intermittent renewable energy sources (RES-E) like wind and photovoltaics will pose challenges to the existing electricity system. A successful integration of these sources requires a cost-efficient use of system flexibility. The literature on the options to improve system flexibility, and thus the costs of successfully integrating intermittent electricity generating units, is still growing but what is lacking is an overarching systematic view on when to adopt which option in particular energy systems. This paper aims to bridge this gap in literature. We use existing insights on market and network integration of intermittent electricity sources within a regulatory road map framework. The framework allows policy makers and other electricity system stakeholders to arrive at a consistent strategy in dealing with integration issues over a longer period of time. In this contribution we present and explain the framework and apply it for the case of The Netherlands. - Highlights: → Successful integration of intermittent electricity generation requires a cost-efficient use of system flexibility. → An overarching systematic view on when to adopt which flexibility option in particular energy systems was lacking. → We identify a consistent strategy in dealing with integration issues over a longer period of time. → We present this regulatory road map framework and apply it for the case of The Netherlands.

Use of mock-up training to reduce personnel exposure at the North Anna Unit 1 Steam Generator Replacement Project

Energy Technology Data Exchange (ETDEWEB)

Henry, H.G. [Virginia Power, Mineral, VA (United States); Reilly, B.P. [Bechtel Power Corp., Gaithersburg, MD (United States)

1995-03-01

The North Anna Power Station is located on the southern shore of Lake Anna in Louisa County, approximately forty miles northwest of Richmond, Virginia. The two 910 Mw nuclear units located on this site are owned by Virginia Electric and Power Company (Virginia Power) and Old Dominion Electric Cooperative and operated by Virginia Power. Fuel was loaded into Unit 1 in December 1977, and it began commercial operation in June 1978. Fuel was loaded into Unit 2 in April 1980 and began commercial operation in December 1980. Each nuclear unit includes a three-coolant-loop pressurized light water reactor nuclear steam supply system that was furnished by Westinghouse Electric Corporation. Included within each system were three Westinghouse Model 51 steam generators with alloy 600, mill-annealed tubing material. Over the years of operation of Unit 1, various corrosion-related phenomena had occurred that affected the steam generators tubing and degraded their ability to fulfill their heat transfer function. Advanced inspection and repair techniques helped extend the useful life of the steam generators, but projections based on the results of the inspections indicated that the existing steam generators tubing and degraded their ability to fullfill their heat transfer function. Advanced inspection and repair techniques helped extend the useful life of the steam generators, but projections based on the results of the inspections indicated that the existing steam generators would not last their design life and must be repaired. To this end Virginia Power determined that a steam generator replacement (SGR) program was necessary to remove the old steam generator tube bundles and lower shell sections, including the channel heads (collectively called the lower assemblies), and replace them with new lower assemblies incorporating design features that will prevent the degradation problems that the old steam generators had experienced.

Manufacture of steam generator units and components for the AGR power stations at Heysham II and Torness

International Nuclear Information System (INIS)

Glasgow, J.R.; Parkin, K.

1984-01-01

The current AGR Steam Generator is a development of the successful once-through units supplied for the Oldbury Magnox and Hinkley B/Hunterston B AGR power stations. In this paper a brief outline of the evolution of the steam generator design from the earlier gas cooled reactor stations is presented. A description of the main items of fabrication development is given. The production facilities for the manufacture of the units are described. Reference is also made to some of the work on associated components. The early experience on the construction site of installation of the steam generators is briefly outlined. (author)

Manufacture of steam generator units and components for the AGR power stations at Heysham II and Torness

Energy Technology Data Exchange (ETDEWEB)

Glasgow, J R; Parkin, K [N.E.I. Nuclear Systems Ltd., Gateshead, Tyne and Wear (United Kingdom)

1984-07-01

The current AGR Steam Generator is a development of the successful once-through units supplied for the Oldbury Magnox and Hinkley B/Hunterston B AGR power stations. In this paper a brief outline of the evolution of the steam generator design from the earlier gas cooled reactor stations is presented. A description of the main items of fabrication development is given. The production facilities for the manufacture of the units are described. Reference is also made to some of the work on associated components. The early experience on the construction site of installation of the steam generators is briefly outlined. (author)

Graphene-based flexible and stretchable thin film transistors.

Science.gov (United States)

Yan, Chao; Cho, Jeong Ho; Ahn, Jong-Hyun

2012-08-21

Graphene has been attracting wide attention owing to its superb electronic, thermal and mechanical properties. These properties allow great applications in the next generation of optoelectronics, where flexibility and stretchability are essential. In this context, the recent development of graphene growth/transfer and its applications in field-effect transistors are involved. In particular, we provide a detailed review on the state-of-the-art of graphene-based flexible and stretchable thin film transistors. We address the principles of fabricating high-speed graphene analog transistors and the key issues of producing an array of graphene-based transistors on flexible and stretchable substrates. It provides a platform for future work to focus on understanding and realizing high-performance graphene-based transistors.

Capacity flexibility allocation in an outsourced supply chain with reservation

DEFF Research Database (Denmark)

Boulaksil, Youssef; Grunow, Martin; Fransoo, J.C.

2011-01-01

We consider a contract manufacturer that serves a limited number of outsourcers (customers) on a single capacitated production line. the outsourcers have different levels of demand uncertainty and the contract manufacturer faces the question how to allocate the contractual capacity flexibility...... in an optimal way. The contractual capacity flexibility is a contract parameter that sets the amount of demand the contract manufacturer is obliged to accept from the outsourcers. We develop a hierachical model that consists of two decision levels. At the tactical level, the contract manufacturer allocates...... the capacity flexibility to the different outsourcers by maximizing the expected profit. Offering more flexibility to the more uncertain outsourcer generates higher expected revenue, but also increases the expected penalty costs. The allocated capacity flexibilities (determined at the tactical level) are input...

How to design your stand-by diesel generator unit for maximum reliability

International Nuclear Information System (INIS)

Kauffmann, W.M.

1979-01-01

Critical stand-by power applications, such as in a nuclear plant, or radio support stations, demand exacting guidelines for positive start, rapid acceleration, load acceptance with minimum voltage drop, and quick recovery to rated voltage. The design of medium-speed turbocharged and intercooled diesel-engine-generator for this purpose is considered. Selection of the diesel engine, size, and number of units, from the standpoint of cost, favors minimum number of units with maximum horsepower capability. Four-cycle diesels are available in 16 to 20 cyinders V-configurations, with 200 BMEP (brake mean-effective pressure) continuous and 250 BMEP peaking

Analysis of IGCC-based plants with carbon capture for an efficient and flexible electric power generation

International Nuclear Information System (INIS)

Sorgenfrei, Max

2016-01-01

In this work, systems based on the Integrated gasification combined cycle (IGCC) technology with carbon capture are analyzed regarding an efficient and flexible electric power generation. All analysis are related to a high-efficiency or low-cost IGCC base case with carbon capture which are both commercially available. In the high-efficiency base case, thermodynamic inefficiencies are determined based on a conventional exergy analysis. The gasifier followed by the combustion chamber of the gas turbine running on syngas are rated to the largest inefficiencies. Based on an advanced exergy analysis, the inefficiencies are split into an avoidable and unavoidable part as well as an endogenous and exogenous part. For example, it was found that about half of the inefficiencies within the gasifier are caused by other components of the overall system(exogenous part). Further investigations on the combination of both splitting types are presented. The gas turbine system is identified to be a major component and therefore a detailed model was developed using state-of-the-art technologies. Based on this model, 12 types of characteristic inefficiencies were determined and rated by their exergy destruction. Chemical-Looping Combustion (CLC) is one of the most promising technologies to enhance the available IGCC design. CLC uses composite metal particles acting as an oxygen carrier to transport oxygen from the air to the fuel gas through a redox-cycle. Thus, the inefficiencies associated with the combustion process decrease and the application of physical absorption for capturing CO 2 is replaced by an inherent CO 2 -capture. In this work, the most suitable oxygen carriers for CLC using syngas (nickel oxide and iron oxide) are analyzed at different temperatures. Moreover, different types of gasifier as well as CLC reactor designs are analyzed. Regenerating the oxygen carrier by steam and air, produces additional hydrogen from the reduction of steam which is further combusted

Adaptive Encoding of Outcome Prediction by Prefrontal Cortex Ensembles Supports Behavioral Flexibility.

Science.gov (United States)

Del Arco, Alberto; Park, Junchol; Wood, Jesse; Kim, Yunbok; Moghaddam, Bita

2017-08-30

The prefrontal cortex (PFC) is thought to play a critical role in behavioral flexibility by monitoring action-outcome contingencies. How PFC ensembles represent shifts in behavior in response to changes in these contingencies remains unclear. We recorded single-unit activity and local field potentials in the dorsomedial PFC (dmPFC) of male rats during a set-shifting task that required them to update their behavior, among competing options, in response to changes in action-outcome contingencies. As behavior was updated, a subset of PFC ensembles encoded the current trial outcome before the outcome was presented. This novel outcome-prediction encoding was absent in a control task, in which actions were rewarded pseudorandomly, indicating that PFC neurons are not merely providing an expectancy signal. In both control and set-shifting tasks, dmPFC neurons displayed postoutcome discrimination activity, indicating that these neurons also monitor whether a behavior is successful in generating rewards. Gamma-power oscillatory activity increased before the outcome in both tasks but did not differentiate between expected outcomes, suggesting that this measure is not related to set-shifting behavior but reflects expectation of an outcome after action execution. These results demonstrate that PFC neurons support flexible rule-based action selection by predicting outcomes that follow a particular action. SIGNIFICANCE STATEMENT Tracking action-outcome contingencies and modifying behavior when those contingencies change is critical to behavioral flexibility. We find that ensembles of dorsomedial prefrontal cortex neurons differentiate between expected outcomes when action-outcome contingencies change. This predictive mode of signaling may be used to promote a new response strategy at the service of behavioral flexibility. Copyright © 2017 the authors 0270-6474/17/378363-11$15.00/0.

75 FR 15745 - Arizona Public Service Company, et al. Palo Verde Nuclear Generating Station, Units 1, 2, and 3...

Science.gov (United States)

2010-03-30

...] Arizona Public Service Company, et al. Palo Verde Nuclear Generating Station, Units 1, 2, and 3; Exemption 1.0 Background The Arizona Public Service Company (APS, the licensee) is the holder of Facility... Generating Station (PVNGS), Units 1, 2, and 3, respectively. The licenses provide, among other things, that...

75 FR 8149 - Arizona Public Service Company, et al. Palo Verde Nuclear Generating Station, Units 1, 2, and 3...

Science.gov (United States)

2010-02-23

...] Arizona Public Service Company, et al. Palo Verde Nuclear Generating Station, Units 1, 2, and 3... NPF-74, issued to the Arizona Public Service Company (APS, or the licensee), for operation of the Palo Verde Nuclear Generating Station (PVNGS, the facility), Units 1, 2, and 3, respectively, located in...

SCC500: next-generation infrared imaging camera core products with highly flexible architecture for unique camera designs

Science.gov (United States)

Rumbaugh, Roy N.; Grealish, Kevin; Kacir, Tom; Arsenault, Barry; Murphy, Robert H.; Miller, Scott

2003-09-01

A new 4th generation MicroIR architecture is introduced as the latest in the highly successful Standard Camera Core (SCC) series by BAE SYSTEMS to offer an infrared imaging engine with greatly reduced size, weight, power, and cost. The advanced SCC500 architecture provides great flexibility in configuration to include multiple resolutions, an industry standard Real Time Operating System (RTOS) for customer specific software application plug-ins, and a highly modular construction for unique physical and interface options. These microbolometer based camera cores offer outstanding and reliable performance over an extended operating temperature range to meet the demanding requirements of real-world environments. A highly integrated lens and shutter is included in the new SCC500 product enabling easy, drop-in camera designs for quick time-to-market product introductions.

Unemployment and External and Internal Labor Market Flexibility: A Comparative View of Europe, Japan, and the United States

OpenAIRE

David Kucera

1998-01-01

This paper examines the relationship between unemployment and labor market flexibility. The latter is considered in the broadest sense - as it relates to labor markets at large (external flexibility) and to practices within firms (internal flexibility). The first part of the paper addresses the argument that differences in employment performance among the advanced economies result largely from differences in labor market flexibility. Empirical evidence is considered on nominal and real wage f...

Levelised unit electricity cost comparison of alternate technologies for baseload generation in Ontario

International Nuclear Information System (INIS)

Ayres, M.; McRae, M.; Stogran, M.

2004-08-01

This report provides a comparison of the lifetime cost of constructing, operating and decommissioning new generation suitable for supplying baseload power by early in the next decade. New baseload generation options in Ontario are nuclear, coal-fired steam turbines or combined cycle gas turbines (CCGT). Nuclear and coal-fired units are characterised by high capital costs and low operating costs. As such, they are candidates for baseload operation only. Gas-fired generation is characterised by lower capital costs and higher operating costs and thus may meet the requirements for operation as peaking and/or baseload generation. The comparison of baseload generating technologies is made by reference to the estimated levelised unit electricity cost (LUEC). The LUEC can be thought of as a 'supply cost', where the unit cost is the price needed to recover all costs over the period. It is determined by finding the price that sets the sum of all future discounted cash flows (net present value, or NPV) to zero. It can also be thought of as representing the constant real wholesale price of electricity that meets the financing cost, debt repayment, income tax and cash flow constraints associated with the construction operation and decommissioning of a generating plant. Levelised unit cost comparisons are usually made with different sets of financing assumptions. This report considers two base cases, which we describe as 'merchant' and 'public' financing. The term 'merchant plant' is used to refer to ones that are built and operated by private investors. These investors pay for their capital through debt and by raising equity, and thus pay return on equity and interest on debt throughout their lifetime. These projects include income taxes, both provincial and federal. Publicly financed projects typically are not subject to income taxes or to the same constraints on raising finance through issuing debt and equity. However, they are constrained to provide a rate of return. The

Value of flexibility in systems with large wind penetration

OpenAIRE

Silva , Vera

2010-01-01

The focus of this thesis is the quantification of the value of operation flexibility in systems with large penetration of wind generation. This begins with the quantification of the impact of wind generation (WG) uncertainty on the system's needs for frequency regulation and reserve. This is done by combing the stochastic behaviour of wind generation, demand uncertainty and generation outages. Two different approaches are compared to access the implications of using normal distribution approx...

Geothermal energy in the western United States and Hawaii: Resources and projected electricity generation supplies

International Nuclear Information System (INIS)

1991-09-01

Geothermal energy comes from the internal heat of the Earth, and has been continuously exploited for the production of electricity in the United States since 1960. Currently, geothermal power is one of the ready-to-use baseload electricity generating technologies that is competing in the western United States with fossil fuel, nuclear and hydroelectric generation technologies to provide utilities and their customers with a reliable and economic source of electric power. Furthermore, the development of domestic geothermal resources, as an alternative to fossil fuel combustion technologies, has a number of associated environmental benefits. This report serves two functions. First, it provides a description of geothermal technology and a progress report on the commercial status of geothermal electric power generation. Second, it addresses the question of how much electricity might be competitively produced from the geothermal resource base. 19 figs., 15 tabs

Large-area high-efficiency flexible PHOLED lighting panels

Science.gov (United States)

Pang, Huiqing; Mandlik, Prashant; Levermore, Peter A.; Silvernail, Jeff; Ma, Ruiqing; Brown, Julie J.

2012-09-01

Organic Light Emitting Diodes (OLEDs) provide various attractive features for next generation illumination systems, including high efficiency, low power, thin and flexible form factor. In this work, we incorporated phosphorescent emitters and demonstrated highly efficient white phosphorescent OLED (PHOLED) devices on flexible plastic substrates. The 0.94 cm2 small-area device has total thickness of approximately 0.25 mm and achieved 63 lm/W at 1,000 cd/m2 with CRI = 85 and CCT = 2920 K. We further designed and fabricated a 15 cm x 15 cm large-area flexible white OLED lighting panels, finished with a hybrid single-layer ultra-low permeability single layer barrier (SLB) encapsulation film. The flexible panel has an active area of 116.4 cm2, and achieved a power efficacy of 47 lm/W at 1,000 cd/m2 with CRI = 83 and CCT = 3470 K. The efficacy of the panel at 3,000 cd/m2 is 43 lm/W. The large-area flexible PHOLED lighting panel is to bring out enormous possibilities to the future general lighting applications.

The Development of the Ventral Prefrontal Cortex and Social Flexibility

Science.gov (United States)

Nelson, Eric E.; Guyer, Amanda E.

2011-01-01

Over the last several years a number of studies in both humans and animals have suggested that the orbitofrontal and ventrolateral prefrontal cortices play an important role in generating flexible behavior. We suggest that input from these brain regions contribute to three functions involved in generating flexible behavior within social contexts: valuation, inhibition, and rule use. Recent studies have also demonstrated that the prefrontal cortex undergoes a prolonged course of maturation that extends well after puberty. Here, we review evidence that the prolonged development of these prefrontal regions parallels a slowly emerging ability for flexible social behavior. We also speculate on the possibility that sensitive periods for organizing social behavior may be embedded within this developmental time-fame. Finally, we discuss the role of prefrontal cortex in adolescent mood and anxiety disorders, particularly as orbitofrontal and ventrolateral prefrontal cortices are engaged in a social context. PMID:21804907

Native Cellulose Microfiber-Based Hybrid Piezoelectric Generator for Mechanical Energy Harvesting Utility.

Science.gov (United States)

Alam, Md Mehebub; Mandal, Dipankar

2016-01-27

A flexible hybrid piezoelectric generator (HPG) based on native cellulose microfiber (NCMF) and polydimethylsiloxane (PDMS) with multi wall carbon nanotubes (MWCNTs) as conducting filler is presented where the further chemical treatment of the cellulose and traditional electrical poling steps for piezoelectric voltage generation is avoided. It delivers a high electrical throughput that is an open circuit voltage of ∼30 V and power density ∼9.0 μW/cm(3) under repeated hand punching. We demonstrate to power up various portable electronic units by HPG. Because cellulose is a biocompatible material, suggesting that HPG may have greater potential in biomedical applications such as implantable power source in human body.

Advancing System Flexibility for High Penetration Renewable Integration

Energy Technology Data Exchange (ETDEWEB)

Milligan, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Frew, Bethany [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zhou, Ella [National Renewable Energy Lab. (NREL), Golden, CO (United States); Arent, Douglas J. [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States)

2015-10-01

This report summarizes some of the issues discussed during the engagement on power system flexibility. By design, the focus is on flexibility options used in the United States. Exploration of whether and how U.S. experiences can inform Chinese energy planning will be part of the continuing project, and will benefit from the knowledge base provided by this report. We believe the initial stage of collaboration represented in this report has successfully started a process of mutual understanding, helping Chinese researchers to begin evaluating how lessons learned in other countries might translate to China's unique geographic, economic, social, and political contexts.

The value of flexibility in power markets

International Nuclear Information System (INIS)

Goutte, Stephane; Vassilopoulos, Philippe

2017-01-01

In this paper we attempt to quantify the net revenues that can be captured by a flexible resource able to react to the short term price variations on the day-ahead and intra-day markets in Germany. We find that the difference between day-ahead and intra-day revenues for a flexible resource has been increasing (although the profitability has been decreasing on both markets). This difference is more pronounced once 15 mn price variations can be captured by a flexible resource. The net revenues from the local 15 mn auction (which is held 3 hours after the hourly 'coupled' day-ahead auction) are more than eight times higher than the day-ahead hourly auction but below the net revenues that can be captured with the high prices from the continuous market. The results of the backward-looking empirical estimations allow us to distinguish and quantify two components of flexibility: (1) the 'immediacy' value as we are approaching real-time and the urgency of the delivery increases (this value is revealed during the continuous intra-day process and is highly linked to the stochastic nature of power supply and demand (i.e. wind/solar forecasts, forced outages of thermal generation,...) forecast error risk), and (2) the 'flexibility' component as a resource can react to variations of shorter granularity (15 mn Vs 60 mn). We model and quantify the 'flexibility' component. (authors)

Dynamic Behavior of Wind Turbine by a Mixed Flexible-Rigid Multi-Body Model

Science.gov (United States)

Wang, Jianhong; Qin, Datong; Ding, Yi

A mixed flexible-rigid multi-body model is presented to study the dynamic behavior of a horizontal axis wind turbine. The special attention is given to flexible body: flexible rotor is modeled by a newly developed blade finite element, support bearing elasticities, variations in the number of teeth in contact as well as contact tooth's elasticities are mainly flexible components in the power train. The couple conditions between different subsystems are established by constraint equations. The wind turbine model is generated by coupling models of rotor, power train and generator with constraint equations together. Based on this model, an eigenproblem analysis is carried out to show the mode shape of rotor and power train at a few natural frequencies. The dynamic responses and contact forces among gears under constant wind speed and fixed pitch angle are analyzed.

Flexibility and a Departmental Instructional Planning Model.

Science.gov (United States)

Miner, Norris

The flexibility of an educational program, institution, or system can be described as the ability of the unit to absorb negative responses, such as reductions in funding or enrollments, and continue to function in a viable manner. One approach to adjustment to such reductions is to effect cuts in personnel, current, and equipment spending. This…

Capacity enhancement and flexible operation of unified power quality conditioner in smart and microgrid network

OpenAIRE

Khadem, Shafiuzzaman Khan; Basu, Malabika; Conlon, Michael F.

2018-01-01

This paper presents a new approach to design Unified Power Quality Conditioner (UPQC), termed as distributed UPQC (D-UPQC), for smart or microgrid network where capacity enhancement and flexible operation of UPQC are the important issues. This paper shows the possibility of capacity enhancement and operational flexibility of UPQC through a coordinated control of existing resources. This UPQC consists of a single unit series active power filter (APFse) and multiple shunt APF (APFsh) units in a...

Feasibility of mini-tablets as a flexible drug delivery tool.

Science.gov (United States)

Mitra, Biplob; Chang, Jessica; Wu, Sy-Juen; Wolfe, Chad N; Ternik, Robert L; Gunter, Thomas Z; Victor, Michael C

2017-06-15

Mini-tablets have potential applications as a flexible drug delivery tool in addition to their generally perceived use as multi-particulates. That is, mini-tablets could provide flexibility in dose finding studies and/or allow for combination therapies in the clinic. Moreover, mini-tablets with well controlled quality attributes could be a prudent choice for administering solid dosage forms as a single unit or composite of multiple mini-tablets in patient populations with swallowing difficulties (e.g., pediatric and geriatric populations). This work demonstrated drug substance particle size and concentration ranges that achieve acceptable mini-tablet quality attributes for use as a single or composite dosage unit. Immediate release and orally disintegrating mini-tablet formulations with 30μm to 350μm (particle size d 90 ) acetaminophen and Compap™ L (90% acetaminophen) at concentrations equivalent to 6.7% and 26.7% acetaminophen were evaluated. Mini-tablets achieved acceptable weight variability, tensile strength, friability, and disintegration time at a reasonable solid fraction for each formulation. The content uniformity was acceptable for mini-tablets of 6.7% formulations with ≤170μm drug substance, mini-tablets of all 26.7% formulations, and composite dosage units containing five or more mini-tablets of any formulation. Results supported the manufacturing feasibility of quality mini-tablets, and their applicability as a flexible drug delivery tool. Copyright © 2017 Elsevier B.V. All rights reserved.

Reducing Approximation Error in the Fourier Flexible Functional Form

Directory of Open Access Journals (Sweden)

Tristan D. Skolrud

2017-12-01

Full Text Available The Fourier Flexible form provides a global approximation to an unknown data generating process. In terms of limiting function specification error, this form is preferable to functional forms based on second-order Taylor series expansions. The Fourier Flexible form is a truncated Fourier series expansion appended to a second-order expansion in logarithms. By replacing the logarithmic expansion with a Box-Cox transformation, we show that the Fourier Flexible form can reduce approximation error by 25% on average in the tails of the data distribution. The new functional form allows for nested testing of a larger set of commonly implemented functional forms.

Flexible Bronchoscopy.

Science.gov (United States)

Miller, Russell J; Casal, Roberto F; Lazarus, Donald R; Ost, David E; Eapen, George A

2018-03-01

Flexible bronchoscopy has changed the course of pulmonary medicine. As technology advances, the role of the flexible bronchoscope for both diagnostic and therapeutic indications is continually expanding. This article reviews the historical development of the flexible bronchoscopy, fundamental uses of the flexible bronchoscope as a tool to examine the central airways and obtain diagnostic tissue, and the indications, complications, and contraindications to flexible bronchoscopy. Copyright © 2017 Elsevier Inc. All rights reserved.

Geomorphic Unit Tool (GUT): Applications of Fluvial Mapping

Science.gov (United States)

Kramer, N.; Bangen, S. G.; Wheaton, J. M.; Bouwes, N.; Wall, E.; Saunders, C.; Bennett, S.; Fortney, S.

2017-12-01

Geomorphic units are the building blocks of rivers and represent distinct habitat patches for many fluvial organisms. We present the Geomorphic Unit Toolkit (GUT), a flexible GIS geomorphic unit mapping tool, to generate maps of fluvial landforms from topography. GUT applies attributes to landforms based on flow stage (Tier 1), topographic signatures (Tier 2), geomorphic characteristics (Tier 3) and patch characteristics (Tier 4) to derive attributed maps at the level of detail required by analysts. We hypothesize that if more rigorous and consistent geomorphic mapping is conducted, better correlations between physical habitat units and ecohydraulic model results will be obtained compared to past work. Using output from GUT for coarse bed tributary streams in the Columbia River Basin, we explore relationships between salmonid habitat and geomorphic spatial metrics. We also highlight case studies of how GUT can be used to showcase geomorphic impact from large wood restoration efforts. Provided high resolution topography exists, this tool can be used to quickly assess changes in fluvial geomorphology in watersheds impacted by human activities.

ANALISIS KEJADIAN STEAM GENERATOR TUBE RUPTURE (SGTR BERDASARKAN SKENARIO MIHAMA UNIT 2

Directory of Open Access Journals (Sweden)

Andi Sofrany Ekariansyah

2015-03-01

Full Text Available Pada tanggal 9 Februari 1991, terjadi kecelakaan putusnya pipa pemanas pembangkit uap (Steam Generator Tube Rupture/SGTR pada PLTN Mihama Unit 2. Dari kejadian tersebut, diperoleh catatan sekuensi kecelakaan berupa aktuasi sistem proteksi dan fitur keselamatan terekayasa dalam memitigasi kebocoran dari sistem primer ke sistem sekunder. Urutan sekuensi tersebut kemudian diterapkan pada PWR standar Jepang untuk disimulasikan menggunakan program perhitungan RELAP5/SCDAP/Mod3.2. Tujuannya untuk mengevaluasi konsekuensi yang terjadi bila kecelakaan tersebut terjadi pada PWR standar Jepang. Parameter yang dibandingkan adalah laju alir kebocoran, perubahan tekanan primer dan sekunder dan perubahan level di dalam pressurizer. Hasil simulasi menunjukkan perbedaan lama waktu kejadian SGTR hingga berhentinya kebocoran yang berlangsung lebih pendek pada PWR standar Jepang. Selain itu jumlah pendingin primer yang bocor dan jumlah uap yang terlepas dari MSRV tercatat lebih besar daripada PWR Mihama unit 2. Karakter aliran kebocoran, fluktuasi tekanan primer, dan level pressurizer sedikit berbeda pada tahap-tahap awal kejadian, namun relatif sama pada tahap akhir ketika aliran kebocoran dapat dihentikan. Hasil simulasi juga menunjukkan perlunya tindakan operator secara manual yang ditunjukkan dari isolasi sistem air umpan bantu (AFW pada pembangkit uap yang bocor, aktuasi katup pelepas uap (MSRV pada pembangkit uap yang utuh dan aktuasi auxiliary spray dan power operated relief valve (PORV pada pressurizer untuk mengantisipasi kejadian sebagai bagian dari prosedur operasi darurat. Kata kunci: SGTR, PWR Mihama Unit 2, PWR standar Jepang   On February 9,1991, a Steam Generator Tube Rupture (SGTR took place at the Mihama Unit No. 2. From that event, the accident sequence representing the actuation of protection system and engineered safety feature to mitigate the leak from primary system to secondary system is recorded. That sequence is then applied on the

Polygenetic Aspect of Unit Theory Oil Generation

Science.gov (United States)

Galant, Yuri

2015-04-01

In the framework of a unified theory Oil Generation one of important moments is the consideration of the distribution of oil in the Earth's Crust. Analysis of the distribution of oil deposits in the Earth's Crust showed that oil distributed throughout the stratigraphic section from ancient to modern sediments and from a depth of 12 kilometers to the Earth's surface. The distribution of oil almost meets all stages of metamorphism of rocks. Correlation of the section of oil distribution to genetic types of ore deposits showed that each genetic type ore deposits has its analogue oil field . So it is possible to classify oil fields on 1) endogenous: the actual magmatic, post-magmatic, contact-metasomatic (skarn), hydrothermal, exhalation, carbonatite, pegmatite, 2) exogenous: weathering, oxidation, sedimentary,3) metamorphogenic: metamorphosed, metamorphic. Model of such distribution of oil deposits can be a process of successive formation of oil deposits of mantle degassing tube. Thus oil is polygenic by way of formation of deposits, but their source is united.

Systematic study of the structure of alternate pyromellitimide-PEO copolymers: Influence of the chain flexibility

International Nuclear Information System (INIS)

Djurado, David; Curtet, Jean Pierre; Bee, Marc; Michot, Christophe; Armand, Michel

2007-01-01

The structure of a family of copolyimides in which are alternating stiff/redox pyromellitimide units and flexible/solvating polyethyleneoxide (PEO) strands were studied by using wide angle and small angle X-ray scattering techniques and is fully discussed. It is shown that the rich variety of structures exhibited by these compounds can be understood by considering the dramatic change of flexibility of the chain induced by the variation of the length of the PEO strand compared to that of the pyromellimide segment. In this respect, concerning the compounds which exhibit fully amorphous structures a better understanding of their structural behavior can be obtained in the framework of Flory's theory of semi-rigid polymers. In this approach, the degree of flexibility of the chain is mainly resulting from the relative amount of flexible units constituting the repetition unit of the polymer chain. The final structural mode adopted by each compound in the solid state is then directly a consequence of this intrinsic property of the chain. The introduction of a lithium salt in contact with the copolymer chains induces some structure changes which can also be explained by the modification of the degree of flexibility of the chain. It is found that the best performances in terms of electroactivity and mixed conduction are precisely obtained with the only compound which keeps full amorphicity in absence and in presence of the lithium salt

Coalition of distributed generation units to virtual power players - a game theory approach

DEFF Research Database (Denmark)

Morais, Hugo; Sousa, Tiago M; Santos, Gabriel

2015-01-01

and the existence of new management players such as several types of aggregators. This paper proposes a methodology to facilitate the coalition between distributed generation units originating Virtual Power Players (VPP) considering a game theory approach. The proposed approach consists in the analysis...... strategies, size and goals, each parameter has different importance. VPP can also manage other type of energy resources, like storage units, electric vehicles, demand response programs or even parts of the MV and LV distribution network. A case study with twelve VPPs with different characteristics and one...

A Flexible Power Electronics Configuration for Coupling Renewable Energy Sources

Directory of Open Access Journals (Sweden)

Mattia Filippini

2015-05-01

Full Text Available A combination of series, parallel and multilevel power electronics has been investigated as a potential interface for two different types of renewable energy sources and in order to reach higher power levels. Renewable energy sources are typically dispersed in a territory, and sources, like wind and solar, allow small to medium-scale generation of electricity. The configuration investigated in this article aims at adapting the coupling solution to the specific generation characteristics of the renewable energy source to make it fit the electrical network. The configuration consists of a combination of three-phase multilevel converters and single-phase inverters, which are designed to provide flexibility, high power quality and high efficiency. A detailed analysis and simulation is performed to identify the properties in conjunction with the electrical grid requirements and the potential challenges encountered during operation. An optimized operation example of wind generation combined with solar PV generation is presented to exemplify the flexibility and benefits of the proposed configuration.

Loss Allocation in a Distribution System with Distributed Generation Units

DEFF Research Database (Denmark)

Lund, Torsten; Nielsen, Arne Hejde; Sørensen, Poul Ejnar

2007-01-01

In Denmark, a large part of the electricity is produced by wind turbines and combined heat and power plants (CHPs). Most of them are connected to the network through distribution systems. This paper presents a new algorithm for allocation of the losses in a distribution system with distributed...... generation. The algorithm is based on a reduced impedance matrix of the network and current injections from loads and production units. With the algorithm, the effect of the covariance between production and consumption can be evaluated. To verify the theoretical results, a model of the distribution system...

Prevention of pulsations caused by flexible risers

NARCIS (Netherlands)

Belfroid S.P.C; Golliard, J.; Korst, H.J.C.

2013-01-01

In the last few decades, flexible risers have increasingly been used in the offshore oil and gas industry. In gas applications these risers can generate high amplitude tonal pressure fluctuations when the gas velocity reaches a threshold value. The resulting pressure fluctuations can then cause high

Development of Megawatt Demand Setter for Plant Operating Flexibility

International Nuclear Information System (INIS)

Kim, Se Chang; Hah, Yeong Joon; Song, In Ho; Lee, Myeong Hun; Chang, Do Ik; Choi, Jung In

1993-05-01

The Conceptual design of the Megawatt Demand Setter (MDS) is presented for the Korean Standardized Nuclear Power Plant. The MDS is a digital supervisory limitation system. The MDS assures that the plant does not exceed the operating limits by regulating the plant operations through monitoring the operating margins of the critical parameters. MDS is aimed at increasing the operating flexibility which allow the nuclear plant to meet the grid demand in very efficient manner. It responds to the grid demand without penalizing plant availability by limiting the load demand when the operating limits are approached or violated. MDS design concepts were tested using simulation responses of Yonggwang Units 3, 4. The design of the Yonggwang Units 3, 4 would be used as a reference which designs of Korean Standardized Nuclear Power Plants would be based upon. The simulation results illustrate that the MDS can be used to improve operating flexibility. (Author)

Layout design optimization of dynamic environment flexible manufacturing systems

Directory of Open Access Journals (Sweden)

Jaber Abu Qudeiri

2015-06-01

Full Text Available The proper positioning of machine tools in flexible manufacturing system is one of the factors that lead to increase in production efficiency. Choosing the optimum position of machine tools curtails the total part handling cost between machine tools within the flexible manufacturing system. In this article, a two-stage approach is presented to investigate the best locations of the machine tools in flexible manufacturing system. The location of each machine tool is selected from the available specific and fixed locations in such a way that it will result in best throughput of the flexible manufacturing system. In the first stage of the two-stage approach, the throughput of randomly selected locations of the machine tool in flexible manufacturing system is computed by proposing a production simulation system. The production simulation system utilizes genetic algorithms to find the locations of the machine tools in flexible manufacturing system that achieve the maximum throughput of the flexible manufacturing system. In the second stage, the generated locations are fed into artificial neural network to find a relation between a machine tool’s location and the throughput that can be used to predict the throughput for any other set of locations. Artificial neural network will result in mitigating the computational time.

Interfacial characterization of flexible hybrid electronics

Science.gov (United States)

Najafian, Sara; Amirkhizi, Alireza V.; Stapleton, Scott

2018-03-01

Flexible Hybrid Electronics (FHEs) are the new generation of electronics combining flexible plastic film substrates with electronic devices. Besides the electrical features, design improvements of FHEs depend on the prediction of their mechanical and failure behavior. Debonding of electronic components from the flexible substrate is one of the most common and critical failures of these devices, therefore, the experimental determination of material and interface properties is of great importance in the prediction of failure mechanisms. Traditional interface characterization involves isolated shear and normal mode tests such as the double cantilever beam (DCB) and end notch flexure (ENF) tests. However, due to the thin, flexible nature of the materials and manufacturing restrictions, tests mirroring traditional interface characterization experiments may not always be possible. The ideal goal of this research is to design experiments such that each mode of fracture is isolated. However, due to the complex nonlinear nature of the response and small geometries of FHEs, design of the proper tests to characterize the interface properties can be significantly time and cost consuming. Hence numerical modeling has been implemented to design these novel characterization experiments. This research involves loading case and specimen geometry parametric studies using numerical modeling to design future experiments where either shear or normal fracture modes are dominant. These virtual experiments will provide a foundation for designing similar tests for many different types of flexible electronics and predicting the failure mechanism independent of the specific FHE materials.

Operation optimization of distributed generation using artificial intelligent techniques

Directory of Open Access Journals (Sweden)

Mahmoud H. Elkazaz

2016-06-01

Full Text Available Future smart grids will require an observable, controllable and flexible network architecture for reliable and efficient energy delivery. The use of artificial intelligence and advanced communication technologies is essential in building a fully automated system. This paper introduces a new technique for online optimal operation of distributed generation (DG resources, i.e. a hybrid fuel cell (FC and photovoltaic (PV system for residential applications. The proposed technique aims to minimize the total daily operating cost of a group of residential homes by managing the operation of embedded DG units remotely from a control centre. The target is formed as an objective function that is solved using genetic algorithm (GA optimization technique. The optimal settings of the DG units obtained from the optimization process are sent to each DG unit through a fully automated system. The results show that the proposed technique succeeded in defining the optimal operating points of the DGs that affect directly the total operating cost of the entire system.

Origin of strain-induced resonances in flexible terahertz metamaterials

International Nuclear Information System (INIS)

Sun Xiu-Yun; Li Xiao-Ning; Xu Hua; Liang Xian-Ting; Zheng Li-Ren; Zhang Xian-Peng; Lu Yue-Hui; Song Wei-Jie; Lee, Young-Pak; Rhee, Joo-Yull

2016-01-01

Two types of flexible terahertz metamaterials were fabricated on polyethylene naphthalate (PEN) substrates. The unit cell of one type consists of two identical split-ring resonators (SRRs) that are arranged face-to-face (i.e., FlexMetaF); the unit cell of the other type has nothing different but is arranged back-to-back (i.e., FlexMetaB). FlexMetaF and FlexMetaB illustrate the similar transmission dips under zero strain because the excitation of fundamental inductive–capacitive (LC) resonance is mainly dependent on the geometric structure of individual SRR. However, if a gradually variant strain is applied to bend FlexMetaF and FlexMetaB, the new resonant peaks appear: in the case of FlexMetaF, the peaks are located at the lower frequencies; in the case of FlexMetaB, the peaks appear at the frequencies adjacent to the LC resonance. The origin and evolution of strain-induced resonances are studied. The origin is ascribed to the detuning effect and the different responses to strain from FlexMetaF and FlexMetaB are associated with the coupling effect. These findings may improve the understanding on flexible terahertz metamaterials and benefit their applications in flexible or curved devices. (paper)

Method for controlling a nuclear fueled electric power generating unit and interfacing the same with a load dispatching system

International Nuclear Information System (INIS)

Mueller, N.P.; Meyer, C.E.

1984-01-01

A pressurized water reactor (PWR) nuclear fueled, electric power generating unit is controlled through the use of on-line calculations of the rapid, step and ramp, power change capabilities of the unit made from measured values of power level, axial offset, coolant temperature and rod position taking into account operator generated, safety and control, and balance of plant limits. The power change capabilities so generated may be fed to an automatic dispatch system which provides closed loop control of a power grid system. (author)

Climate change impacts on thermoelectric-power generation in the United States

Science.gov (United States)

Liu, L.

2015-12-01

Thermoelectric-power generation accounts for more than 70% of the total electricity generation in the United States, which requires large amounts of water for cooling purposes. Water withdrawals for thermoelectric-power generation accounted for 45% of total water use in the United States in 2010. Across the country, water demand from power plants is increasing due to pressures from growing populations and other needs, and is straining existing water resources. Moreover, temperature exceedance in receiving waters has increasingly caused power plants shut downs across parts of the country. Thermoelectric power is vulnerable to climate change owing to the combined effects of lower summer river flows and higher receiving water temperatures. In addition, the efficiency of production is reduced as air temperature rises, which propagates to more unfulfilled power demand during peak seasons. Therefore, a holistic modeling framework of water-energy-climate for the contiguous U.S. is presented here to quantify thermal output from power plants and estimate water use and energy production fluctuations due to ambient climate as well as environmental regulations. The model is calibrated on a plant-by-plant basis for year 2010 and 2011 using the available power plant inventory from the Energy Information Administration (EIA). Simulations were carried out for years 2012 and 2013, and results show moderate improvements in capturing thermal output variabilities after calibration. Future power plant operations under scenarios featuring different climate and regulatory settings were investigated. Results demonstrate the interplay among water, energy and climate, and that future changes in climate and socioeconomics significantly affect power plant operations, which may provide insights to climate change mitigation considerations and energy decisions.

Audit of Wolf Creek Generating Station, Unit 1 technical specifications. Final technical evaluation report

International Nuclear Information System (INIS)

Stromberg, H.M.

1985-07-01

This document was prepared for the Nuclear Regulatory Commission (NRC) to assist them in determining whether the Wolf Creek Generating Station Unit 1 Technical Specifications (T/S), which govern plant systems configurations and operations, are in conformance with the assumptions of the Final Safety Analysis Report (FSAR) as amended, the requirements of the Safety Evaluation Report (SER) as supplemented, and the Comments and Responses to the Wolf Creek Technical Specification Draft Inspection Report. A comparative audit of the FSAR as amended, the SER as supplemented, and the Draft Inspection Report was performed with the Wolf Creek T/S. Several discrepancies were identified and subsequently resolved through discussions with the cognizant NRC reviewer, NRC staff reviewers and/or utility representatives. The Wolf Creek Generating Station Unit 1 T/S, to the extent reviewed, are in conformance with the FSAR, SER, and Draft Inspection Report

Retrofitting for fossil fuel flexibility

International Nuclear Information System (INIS)

Newell, J.; Trueblood, R.C.; Lukas, R.W.; Worster, C.M.; Marx, P.D.

1991-01-01

Described in this paper are two fossil plant retrofits recently completed by the Public Service Company of New Hampshire that demonstrate the type of planning and execution required for a successful project under the current regulatory and budget constraints. Merrimack Units 1 and 2 are 120 MW and 338 MW nominal cyclone-fired coal units in Bow, New Hampshire. The retrofits recently completed at these plants have resulted in improved particulate emissions compliance, and the fuel flexibility to allow switching to lower sulphur coals to meet current and future SO 2 emission limits. Included in this discussion are the features of each project including the unique precipitator procurement approach for the Unit 1 Retrofit, and methods used to accomplish both retrofits within existing scheduled maintenance outages through careful planning and scheduling, effective use of pre-outage construction, 3-D CADD modeling, modular construction and early procurement. Operating experience while firing various coals in the cyclone fired boilers is also discussed

Conjugated Polymers for Flexible Energy Harvesting and Storage.

Science.gov (United States)

Zhang, Zhitao; Liao, Meng; Lou, Huiqing; Hu, Yajie; Sun, Xuemei; Peng, Huisheng

2018-03-01

Since the discovery of conjugated polymers in the 1970s, they have attracted considerable interest in light of their advantages of having a tunable bandgap, high electroactivity, high flexibility, and good processability compared to inorganic conducting materials. The above combined advantages make them promising for effective energy harvesting and storage, which have been widely studied in recent decades. Herein, the key advancements in the use of conjugated polymers for flexible energy harvesting and storage are reviewed. The synthesis, structure, and properties of conjugated polymers are first summarized. Then, their applications in flexible polymer solar cells, thermoelectric generators, supercapacitors, and lithium-ion batteries are described. The remaining challenges are then discussed to highlight the future direction in the development of conjugated polymers. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficient industrial burner control of a flexible burner management system; Effiziente industrielle Brennertechnik durch Einsatz flexibler Feuerungsautomaten

Energy Technology Data Exchange (ETDEWEB)

Hofmann, Ulrich; Saenger, Peter [Siemens AG, Rastatt (Germany)

2012-02-15

Compactness and flexibility of a burner control system is a very important issue. With a few types a wide range in different industrial applications should be covered. This paper presents different applications of a new burner control system: heating of cooling lines in glass industry, steam generation and air heating for a pistachio roastery and in grain dryers. (orig.)

Steam generator leak detection at Bruce A Unit 1

International Nuclear Information System (INIS)

Maynard, K.J.; McInnes, D.E.; Singh, V.P.

1997-01-01

A new steam generator leak detection system was recently developed and utilized at Bruce A. The equipment is based on standard helium leak detection, with the addition of moisture detection and several other capability improvements. All but 1% of the Unit 1 Boiler 03 tubesheet was inspected, using a sniffer probe which inspected tubes seven at a time and followed by individual tube inspections. The leak search period was completed in approximately 24 hours, following a prerequisite period of several days. No helium leak indications were found anywhere on the boiler. A single water leak indication was found, which was subsequently confirmed as a through-wall defect by eddy current inspection. (author)

Flexible, fast and accurate sequence alignment profiling on GPGPU with PaSWAS.

Directory of Open Access Journals (Sweden)

Sven Warris

Full Text Available To obtain large-scale sequence alignments in a fast and flexible way is an important step in the analyses of next generation sequencing data. Applications based on the Smith-Waterman (SW algorithm are often either not fast enough, limited to dedicated tasks or not sufficiently accurate due to statistical issues. Current SW implementations that run on graphics hardware do not report the alignment details necessary for further analysis.With the Parallel SW Alignment Software (PaSWAS it is possible (a to have easy access to the computational power of NVIDIA-based general purpose graphics processing units (GPGPUs to perform high-speed sequence alignments, and (b retrieve relevant information such as score, number of gaps and mismatches. The software reports multiple hits per alignment. The added value of the new SW implementation is demonstrated with two test cases: (1 tag recovery in next generation sequence data and (2 isotype assignment within an immunoglobulin 454 sequence data set. Both cases show the usability and versatility of the new parallel Smith-Waterman implementation.

Flexible, fast and accurate sequence alignment profiling on GPGPU with PaSWAS.

Science.gov (United States)

Warris, Sven; Yalcin, Feyruz; Jackson, Katherine J L; Nap, Jan Peter

2015-01-01

To obtain large-scale sequence alignments in a fast and flexible way is an important step in the analyses of next generation sequencing data. Applications based on the Smith-Waterman (SW) algorithm are often either not fast enough, limited to dedicated tasks or not sufficiently accurate due to statistical issues. Current SW implementations that run on graphics hardware do not report the alignment details necessary for further analysis. With the Parallel SW Alignment Software (PaSWAS) it is possible (a) to have easy access to the computational power of NVIDIA-based general purpose graphics processing units (GPGPUs) to perform high-speed sequence alignments, and (b) retrieve relevant information such as score, number of gaps and mismatches. The software reports multiple hits per alignment. The added value of the new SW implementation is demonstrated with two test cases: (1) tag recovery in next generation sequence data and (2) isotype assignment within an immunoglobulin 454 sequence data set. Both cases show the usability and versatility of the new parallel Smith-Waterman implementation.

Flexible Reactive Berm (FRBerm) for Removal of Heavy Metals from Runoff Water

Science.gov (United States)

2016-03-01

coefficient, and sediment clogging coefficients. Also, the flexible reactive barrier system permitted overtopping and filter socks would be arranged in a...FINAL REPORT Flexible Reactive Berm (FRBerm) for Removal of Heavy Metals from Runoff Water ESTCP Project ER-201213 MARCH 2016...GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 6. AUTHOR(S) 7. PERFORMING ORGANIZATION NAME

Levelised unit electricity cost comparison of alternate technologies for baseload generation in Ontario

Energy Technology Data Exchange (ETDEWEB)

Ayres, M.; McRae, M.; Stogran, M.

2004-08-15

This report provides a comparison of the lifetime cost of constructing, operating and decommissioning new generation suitable for supplying baseload power by early in the next decade. New baseload generation options in Ontario are nuclear, coal-fired steam turbines or combined cycle gas turbines (CCGT). Nuclear and coal-fired units are characterised by high capital costs and low operating costs. As such, they are candidates for baseload operation only. Gas-fired generation is characterised by lower capital costs and higher operating costs and thus may meet the requirements for operation as peaking and/or baseload generation. The comparison of baseload generating technologies is made by reference to the estimated levelised unit electricity cost (LUEC). The LUEC can be thought of as a 'supply cost', where the unit cost is the price needed to recover all costs over the period. It is determined by finding the price that sets the sum of all future discounted cash flows (net present value, or NPV) to zero. It can also be thought of as representing the constant real wholesale price of electricity that meets the financing cost, debt repayment, income tax and cash flow constraints associated with the construction operation and decommissioning of a generating plant. Levelised unit cost comparisons are usually made with different sets of financing assumptions. This report considers two base cases, which we describe as 'merchant' and 'public' financing. The term 'merchant plant' is used to refer to ones that are built and operated by private investors. These investors pay for their capital through debt and by raising equity, and thus pay return on equity and interest on debt throughout their lifetime. These projects include income taxes, both provincial and federal. Publicly financed projects typically are not subject to income taxes or to the same constraints on raising finance through issuing debt and equity. However, they are

The nature and necessity of operational flexibility in the emergency department.

Science.gov (United States)

Ward, Michael J; Ferrand, Yann B; Laker, Lauren F; Froehle, Craig M; Vogus, Timothy J; Dittus, Robert S; Kripalani, Sunil; Pines, Jesse M

2015-02-01

Hospital-based emergency departments (EDs), given their high cost and major role in allocating care resources, are at the center of the debate about how to maximize value in delivering health care in the United States. To operate effectively and create value, EDs must be flexible, having the ability to rapidly adapt to the highly variable needs of patients. The concept of flexibility has not been well described in the ED literature. We introduce the concept, outline its potential benefits, and provide some illustrative examples to facilitate incorporating flexibility into ED management. We draw on operations research and organizational theory to identify and describe 5 forms of flexibility: physical, human resource, volume, behavioral, and conceptual. Each form of flexibility may be useful individually or in combination with other forms in improving ED performance and enhancing value. We also offer suggestions for measuring operational flexibility in the ED. A better understanding of operational flexibility and its application to the ED may help us move away from reactive approaches of managing variable demand to a more systematic approach. We also address the tension between cost and flexibility and outline how "partial flexibility" may help resolve some challenges. Applying concepts of flexibility from other disciplines may help clinicians and administrators think differently about their workflow and provide new insights into managing issues of cost, flow, and quality in the ED. Copyright © 2014 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

Technology for 3D System Integration for Flexible Wireless Biomedical Applications

Directory of Open Access Journals (Sweden)

Wen-Cheng Kuo

2018-05-01

Full Text Available This paper presents a new 3D bottom-up packing technology for integrating a chip, an induction coil, and interconnections for flexible wireless biomedical applications. Parylene was used as a flexible substrate for the bottom-up embedding of the chip, insulation layer, interconnection, and inductors to form a flexible wireless biomedical microsystem. The system can be implanted on or inside the human body. A 50-μm gold foil deposited through laser micromachining by using a picosecond laser was used as an inductor to yield a higher quality factor than that yielded by thickness-increasing methods such as the fold-and-bond method or thick-metal electroplating method at the operation frequency of 1 MHz. For system integration, parylene was used as a flexible substrate, and the contact pads and connections between the coil and chip were generated using gold deposition. The advantage of the proposed process can integrate the chip and coil vertically to generate a single biocompatible system in order to reduce required area. The proposed system entails the use of 3D integrated circuit packaging concepts to integrate the chip and coil. The results validated the feasibility of this technology.

A Signal Processing Method to Explore Similarity in Protein Flexibility

Directory of Open Access Journals (Sweden)

Simina Vasilache

2010-01-01

Full Text Available Understanding mechanisms of protein flexibility is of great importance to structural biology. The ability to detect similarities between proteins and their patterns is vital in discovering new information about unknown protein functions. A Distance Constraint Model (DCM provides a means to generate a variety of flexibility measures based on a given protein structure. Although information about mechanical properties of flexibility is critical for understanding protein function for a given protein, the question of whether certain characteristics are shared across homologous proteins is difficult to assess. For a proper assessment, a quantified measure of similarity is necessary. This paper begins to explore image processing techniques to quantify similarities in signals and images that characterize protein flexibility. The dataset considered here consists of three different families of proteins, with three proteins in each family. The similarities and differences found within flexibility measures across homologous proteins do not align with sequence-based evolutionary methods.

A Modular Microfluidic Device via Multimaterial 3D Printing for Emulsion Generation.

Science.gov (United States)

Ji, Qinglei; Zhang, Jia Ming; Liu, Ying; Li, Xiying; Lv, Pengyu; Jin, Dongping; Duan, Huiling

2018-03-19

3D-printing (3DP) technology has been developing rapidly. However, limited studies on the contribution of 3DP technology, especially multimaterial 3DP technology, to droplet-microfluidics have been reported. In this paper, multimaterial 3D-printed devices for the pneumatic control of emulsion generation have been reported. A 3D coaxial flexible channel with other rigid structures has been designed and printed monolithically. Numerical and experimental studies have demonstrated that this flexible channel can be excited by the air pressure and then deform in a controllable way, which can provide the active control of droplet generation. Furthermore, a novel modular microfluidic device for double emulsion generation has been designed and fabricated, which consists of three modules: function module, T-junction module, and co-flow module. The function module can be replaced by (1) Single-inlet module, (2) Pneumatic Control Unit (PCU) module and (3) Dual-inlet module. Different modules can be easily assembled for different double emulsion production. By using the PCU module, double emulsions with different number of inner droplets have been successfully produced without complicated operation of flow rates of different phases. By using single and dual inlet module, various double emulsions with different number of encapsulated droplets or encapsulated droplets with different compositions have been successfully produced, respectively.

Liberalisation of the electricity sector and development of distributed generation: Germany, United Kingdom and France

International Nuclear Information System (INIS)

Menanteau, Ph.

2003-01-01

Historically, electricity systems have been made up of small local networks gradually becoming incorporated to benefit from the diversity of demand and the economies of scale in electricity generation that are possible with large interconnected systems. Today, this logic would seem to have certain limits, now that the benefits related to the size of production units appear to have been exhausted and in view of the growing difficulties in developing new transmission infrastructures. At the same time, there have been considerable improvements in the technical and economic performance of modular generating techniques, which are now enjoying significant development under the effect of electricity sector liberalization and policies to reduce greenhouse gas emissions. The aim of the present paper is to analyse the effect of electricity sector liberalization on the development of distributed generation, and more specifically to examine the conditions in which these new electricity generating technologies can be diffused in a liberalized framework. The paper looks first at how competition has affected the electricity market. This analysis is followed by an examination of the problems of integrating distributed generation into electricity systems. In the third part of the paper, three brief case studies highlight the principal differences between Germany, the United Kingdom and France in the field of distributed generation. This brief analysis reveals that the institutional framework in which distributed generation must operate and the price signals given to electricity sector actors play as big a part as traditional incentives, certificates, bidding systems or guaranteed feed-in tariffs in driving the deployment process. (author)

Wing flexibility effects in clap-and-fling

NARCIS (Netherlands)

Percin, M.; Hu, Y.; Van Oudheusden, B.W.; Remes, B.; Scarano, F.

2011-01-01

The work explores the use of time-resolved tomographic PIV measurements to study a flapping-wing model, the related vortex generation mechanisms and the effect of wing flexibility on the clap-and-fling movement in particular. An experimental setup is designed and realized in a water tank by use of a

Pattern Generator for Bench Test of Digital Boards

Science.gov (United States)

Berkun, Andrew C.; Chu, Anhua J.

2012-01-01

All efforts to develop electronic equipment reach a stage where they need a board test station for each board. The SMAP digital system consists of three board types that interact with each other using interfaces with critical timing. Each board needs to be tested individually before combining into the integrated digital electronics system. Each board needs critical timing signals from the others to be able to operate. A bench test system was developed to support test of each board. The test system produces all the outputs of the control and timing unit, and is delivered much earlier than the timing unit. Timing signals are treated as data. A large file is generated containing the state of every timing signal at any instant. This file is streamed out to an IO card, which is wired directly to the device-under-test (DUT) input pins. This provides a flexible test environment that can be adapted to any of the boards required to test in a standalone configuration. The problem of generating the critical timing signals is then transferred from a hardware problem to a software problem where it is more easily dealt with.

Accelerated Electromechanical Modeling of a Distributed Internal Combustion Engine Generator Unit

Directory of Open Access Journals (Sweden)

Serhiy V. Bozhko

2012-07-01

Full Text Available Distributed generation with a combustion engine prime mover is still widely used to supply electric power in a variety of applications. These applications range from backup power supply systems and combined wind-diesel generation to providing power in places where grid connection is either technically impractical or financially uneconomic. Modelling of such systems as a whole is extremely difficult due to the long-time load profiles needed and the computational difficulty of including small time-constant electrical dynamics with large time-constant mechanical dynamics. This paper presents the development of accelerated, reduced-order models of a distributed internal combustions engine generator unit. Overall these models are shown to achieve a massive improvement in the computational time required for long-time simulations while also achieving an extremely high level of dynamic accuracy. It is demonstrated how these models are derived, used and verified against benchmark models created using established techniques. Throughout the paper the modelling set as a whole, including multi level detail, is presented, detailed and finally summarised into a crucial tool for general system investigation and multiple target optimisation.

Developing a mixture design specification for flexible base construction.

Science.gov (United States)

2012-06-01

In the Texas Department of Transportation (TxDOT), flexible base producers typically generate large stockpiles of material exclusively for TxDOT projects. This large state-only inventory often maintained by producers, along with time requiremen...

Conceptual Design of a Combined Power Generation Unit at the NPP Seaside

International Nuclear Information System (INIS)

Cha, Kyung H.

2011-01-01

In order to improve operational performance, an undersea tunnel is being utilized for in-taking and out-taking seawater as coolant in Nuclear Power Plant (NPP). This paper describes a Combined solar-wind-wave Power Generation Unit (CPGU) to be specialized for in-taking and out-taking seawater as coolant in NPP. Accordingly, the purpose of the CPGU is twofold: one is to contain some tunnels to be maintained on the bottom of the CPGU body in order to in-take and out-take coolant water, and the other is to generate a combined power at the NPP seaside. Fig. 1 shows the conceptual CPGU to be configured at the NPP seaside

Hydro power flexibility for power systems with variable renewable energy sources: an IEA Task 25 collaboration: Hydro power flexibility for power systems

Energy Technology Data Exchange (ETDEWEB)

Huertas-Hernando, Daniel [Department of Energy Systems, SINTEF, Trondheim Norway; Farahmand, Hossein [Department of Electric Power Engineering, Norwegian University of Science and Technology (NTNU), Trondheim Norway; Holttinen, Hannele [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Kiviluoma, Juha [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Rinne, Erkka [Department of Energy Systems, VTT Technical Research Centre of Finland, Espoo Finland; Söder, Lennart [Department of Electrical Engineering, KTH University, Stockholm Sweden; Milligan, Michael [Transmission and Grid Integration Group, National Renewable Energy Laboratory' s National Wind Technology Center, Golden CO USA; Ibanez, Eduardo [Transmission and Grid Integration Group, National Renewable Energy Laboratory' s National Wind Technology Center, Golden CO USA; Martínez, Sergio Martín [Department of Electrical Engineering, Electronics, Automation and Communications, Universidad de Castilla-La Mancha, Albacete Spain; Gomez-Lazaro, Emilio [Department of Electrical Engineering, Electronics, Automation and Communications, Universidad de Castilla-La Mancha, Albacete Spain; Estanqueiro, Ana [National Laboratory of Energy and Geology - LNEG, Lisbon Portugal; Rodrigues, Luis [National Laboratory of Energy and Geology - LNEG, Lisbon Portugal; Carr, Luis [Research Association for Energy Economics (FfE GmbH), Munich Germany; van Roon, Serafin [Research Association for Energy Economics (FfE GmbH), Munich Germany; Orths, Antje Gesa [Energinet.dk, Fredericia Denmark; Eriksen, Peter Børre [Energinet.dk, Fredericia Denmark; Forcione, Alain [Hydro Quebec, Montréal Canada; Menemenlis, Nickie [Hydro Quebec, Montréal Canada

2016-06-20

Hydro power is one of the most flexible sources of electricity production. Power systems with considerable amounts of flexible hydro power potentially offer easier integration of variable generation, e.g., wind and solar. However, there exist operational constraints to ensure mid-/long-term security of supply while keeping river flows and reservoirs levels within permitted limits. In order to properly assess the effective available hydro power flexibility and its value for storage, a detailed assessment of hydro power is essential. Due to the inherent uncertainty of the weather-dependent hydrological cycle, regulation constraints on the hydro system, and uncertainty of internal load as well as variable generation (wind and solar), this assessment is complex. Hence, it requires proper modeling of all the underlying interactions between hydro power and the power system, with a large share of other variable renewables. A summary of existing experience of wind integration in hydro-dominated power systems clearly points to strict simulation methodologies. Recommendations include requirements for techno-economic models to correctly assess strategies for hydro power and pumped storage dispatch. These models are based not only on seasonal water inflow variations but also on variable generation, and all these are in time horizons from very short term up to multiple years, depending on the studied system. Another important recommendation is to include a geographically detailed description of hydro power systems, rivers' flows, and reservoirs as well as grid topology and congestion.

On flexibility

OpenAIRE

Weiss, Christoph R.; Briglauer, Wolfgang

2000-01-01

By building on theoretical work by Mills and Schumann (1985) and Ungern-Sternberg (1990) this paper provides evidence on the determinants of two dimensions of flexibility, the flexibility in adjusting aggregate output over time (tactical flexibility) as well as the ability to switch quickly between products (operational flexibility). Econometric analysis of a sample of 40.000 farms in Upper-Austria for the period 1980 to 1990 suggests that larger full-time farms operated by younger, better ed...

Operating experience gained during the copper oxide plugging incident in Koeberg unit 1 generator stator

International Nuclear Information System (INIS)

Mellor, S.P.; Matthee, F.W.

2002-01-01

In June 1999 Koeberg's unit 1 started to experience adverse operating conditions which were later ascribed to blockages in the hollow conductors of the generator stator. These blockages were attributed to copper oxide plugs which developed progressively during the following year and culminated in reduced power operation. Many attempts were made to address the plugging by implementing various off-line and on-line cleaning processes. Subsequent to a successful on-line cleaning operation, the unit was returned to full power and the chemistry regime for the stator cooling water system was changed to allow for operation at an elevated pH. This paper discusses Koeberg's experience with copper oxide blockages, describes the initial indications of the problem and the impact on the operating parameters. The remainder of the paper focuses on the actions taken to address the deteriorating situation and the different cleaning methods implemented to remove the copper oxide deposits. The paper concludes with the current status of the unit 1 generator stator and the lessons learned during the resolution of this problem. (authors)

Operating experience gained during the copper oxide plugging incident in Koeberg unit 1 generator stator

Energy Technology Data Exchange (ETDEWEB)

Mellor, S.P.; Matthee, F.W. [ESKOM, Koeberg Nuclear Power Station (South Africa)

2002-07-01

In June 1999 Koeberg's unit 1 started to experience adverse operating conditions which were later ascribed to blockages in the hollow conductors of the generator stator. These blockages were attributed to copper oxide plugs which developed progressively during the following year and culminated in reduced power operation. Many attempts were made to address the plugging by implementing various off-line and on-line cleaning processes. Subsequent to a successful on-line cleaning operation, the unit was returned to full power and the chemistry regime for the stator cooling water system was changed to allow for operation at an elevated pH. This paper discusses Koeberg's experience with copper oxide blockages, describes the initial indications of the problem and the impact on the operating parameters. The remainder of the paper focuses on the actions taken to address the deteriorating situation and the different cleaning methods implemented to remove the copper oxide deposits. The paper concludes with the current status of the unit 1 generator stator and the lessons learned during the resolution of this problem. (authors)

Identifying Functional Requirements for Flexible Airspace Management Concept Using Human-In-The-Loop Simulations

Science.gov (United States)

Lee, Paul U.; Bender, Kim; Pagan, Danielle

2011-01-01

Flexible Airspace Management (FAM) is a mid- term Next Generation Air Transportation System (NextGen) concept that allows dynamic changes to airspace configurations to meet the changes in the traffic demand. A series of human-in-the-loop (HITL) studies have identified procedures and decision support requirements needed to implement FAM. This paper outlines a suggested FAM procedure and associated decision support functionality based on these HITL studies. A description of both the tools used to support the HITLs and the planned NextGen technologies available in the mid-term are presented and compared. The mid-term implementation of several NextGen capabilities, specifically, upgrades to the Traffic Management Unit (TMU), the initial release of an en route automation system, the deployment of a digital data communication system, a more flexible voice communications network, and the introduction of a tool envisioned to manage and coordinate networked ground systems can support the implementation of the FAM concept. Because of the variability in the overall deployment schedule of the mid-term NextGen capabilities, the dependency of the individual NextGen capabilities are examined to determine their impact on a mid-term implementation of FAM. A cursory review of the different technologies suggests that new functionality slated for the new en route automation system is a critical enabling technology for FAM, as well as the functionality to manage and coordinate networked ground systems. Upgrades to the TMU are less critical but important nonetheless for FAM to be fully realized. Flexible voice communications network and digital data communication system could allow more flexible FAM operations but they are not as essential.

Telerobotic operation of structurally flexible, long-reach manipulators

International Nuclear Information System (INIS)

Kwon, D.S.; Hwang, D.H.; Babcock, S.M.

1994-01-01

As a part of the Department of Energy's Environmental Restoration and Waste Management Program, long-reach manipulators are being considered for the retrieval of waste from large storage tanks. Long-reach manipulators may have characteristics significantly different from those of typical industrial robots because of the flexibility of long links needed to cover the large workspace. To avoid structural vibrations during operation, control algorithms employing various types of shaping filters were investigated. A new approach that uses embedded simulation was developed and compared with others. In the new approach, generation of joint trajectories considering link flexibility was also investigated

Vibration reduction and power generation with piezoceramic sheets mounted to a flexible shaft

NARCIS (Netherlands)

Sloetjes, P.J.; de Boer, Andries

2008-01-01

A flexible shaft with surface-mounted piezoceramic sheets and strain sensors is considered which suffers from resonance and self-excited vibration. Frequency domain models, time domain simulations, and control experiments are used to analyze active modal damping and active modal balancing methods.

Oil Vulnerabilities and United States Strategy

Science.gov (United States)

2007-02-08

Mazda, Mercedes - Benz , Ford, Mercury, and Nissan offer flexible fuel vehicles in the United States. Ethanol is currently produced in the United States...USAWC STRATEGY RESEARCH PROJECT OIL VULNERABILITIES AND UNITED STATES STRATEGY by Colonel Shawn P. Walsh...Colleges and Schools, 3624 Market Street, Philadelphia, PA 19104, (215) 662-5606. The Commission on Higher Education is an institutional accrediting

Balance and flexibility.

Science.gov (United States)

2003-12-01

The 'work-life balance' and flexible working are currently key buzz terms in the NHS. Those looking for more information on these topics should visit Flexibility at www.flexibility.co.uk for a host of resources designed to support new ways of working, including information on flexible workers and flexible rostering, the legal balancing act for work-life balance and home working.

Microwave Photonics Techniques Supporting Flexible Wireless Communications Links

DEFF Research Database (Denmark)

Rommel, Simon; Cavalcante, Lucas Costa Pereira; Vegas Olmos, Juan José

Wireless data communication links supporting the next generation 5G and beyond mobile networking face a set of engineering challenges related to the mandatory operation at mmw and higher frequency bands, provide capacities above 10 Gb/s, satisfy latency, robustness, flexibility and low complexity...

Palo Verde Generating Station, Units 4 and 5. License application, general information

International Nuclear Information System (INIS)

1978-01-01

A license application for two more Palo Verde reactors, Units 4 and 5, is presented. The two PWR reactors have a nominal net generating power each of 1,270 MW(e). Containments are steel-lined prestressed cylindrical structures with hemispherical domes. The reactors are replicas of Palo Verde 1, 2 and 3 (see DOCKETS 50528, 50529 and 50530) using the standard Combustion Engineering System 80 (see DOCKET-STN-50470)

A review of flexible lithium-sulfur and analogous alkali metal-chalcogen rechargeable batteries.

Science.gov (United States)

Peng, Hong-Jie; Huang, Jia-Qi; Zhang, Qiang

2017-08-29

Flexible energy storage systems are imperative for emerging flexible devices that are revolutionizing our life. Lithium-ion batteries, the current main power sources, are gradually approaching their theoretical limitation in terms of energy density. Therefore, alternative battery chemistries are urgently required for next-generation flexible power sources with high energy densities, low cost, and inherent safety. Flexible lithium-sulfur (Li-S) batteries and analogous flexible alkali metal-chalcogen batteries are of paramount interest owing to their high energy densities endowed by multielectron chemistry. In this review, we summarized the recent progress of flexible Li-S and analogous batteries. A brief introduction to flexible energy storage systems and general Li-S batteries has been provided first. Progress in flexible materials for flexible Li-S batteries are reviewed subsequently, with a detailed classification of flexible sulfur cathodes as those based on carbonaceous (e.g., carbon nanotubes, graphene, and carbonized polymers) and composite (polymers and inorganics) materials and an overview of flexible lithium anodes and flexible solid-state electrolytes. Advancements in other flexible alkali metal-chalcogen batteries are then introduced. In the next part, we emphasize the importance of cell packaging and flexibility evaluation, and two special flexible battery prototypes of foldable and cable-type Li-S batteries are highlighted. In the end, existing challenges and future development of flexible Li-S and analogous alkali metal-chalcogen batteries are summarized and prospected.

[An Exploration of Working Conditions and Flexible System for Hospital Nurses].

Science.gov (United States)

Huang, Chung-I; Yu, Chien; Yu, Chin-Cheh

2016-04-01

The lack of sufficient numbers of professional nurses in the healthcare system in Taiwan is an issue that affects the sustainability of this system and that relates closely to working conditions. The present study explores the expectations that nurses hold with regard to working conditions and the operation of a flexible system in hospitals. A literature review and focus-group interviews were used to develop the questionnaire Working Conditions and Flexible System. A total of 1,150 copies of this questionnaire were distributed to practicing nurses using stratified random sampling, with 1,146 valid copies returned for a valid recovery rate of 99.65%. The results show that the expectations of participants concerning working conditions and a flexible system focus on the 6 factors of task, numerical, divisional, temporal, wages, and leading flexibility. The total mean was 4.35 (SD=0.42). The means for the 6 types of flexibility were all greater than 4.0. Participants deemed flexibility to be of high importance. The demographic variables hospital, work location, age, education level, work position, work unit, and total work years all affected the 6 types of flexibility significantly. The present study supports that the retention of nurses is significantly associated with working conditions and the operation of a flexible system. Administrators and mangers must create positive working conditions and a flexible system in order to enhance the retention and career development of nurses.

Flexible fuel cycle initiative for the transition period from current reactors to next generation reactors

International Nuclear Information System (INIS)

Yamashita, Junichi; Fukasawa, Tetsuo; Hoshino, Kuniyoshi; Kawamura, Fumio; Shiina, Kouji; Sasahira, Akira

2005-01-01

A sustainable electricity supply by fast breeder reactors (FBRs) is essential to ensure energy security and prevent global warming. Transition from light water reactors (LWRs) to FBRs and establishment of an FBR cycle are indispensable, which requires plutonium (Pu) for the introduction of FBRs. The authors propose advanced system called 'Flexible Fuel Cycle Initiative (FFCI)' which can respond flexibly the future expected technical and social uncertainties, can hold no surplus Pu, and can achieve an economical FBR cycle. In the new concept of FFCI, 2nd LWR reprocessing which would succeed Rokkasho Reprocessing Plant is a simple facility to carry out only uranium (U) removal and residual 'recycle material' is stored or utilized. According to FBRs introduction status, recycle material is immediately treated in an FBR reprocessing to fabricate FBR fuel or temporarily stored for the utilization in FBRs at necessary timing. FFCI has high flexibility by having several options for future uncertainties by the introduction of recycle material as a buffer material between LWR and FBR cycles. (author)

Plastic flexible films waste management - A state of art review.

Science.gov (United States)

Horodytska, O; Valdés, F J; Fullana, A

2018-04-21

Plastic flexible films are increasingly used in many applications due to their lightness and versatility. In 2014, the amount of plastic films represented 34% of total plastic packaging produced in UK. The flexible film waste generation rises according to the increase in number of applications. Currently, in developed countries, about 50% of plastics in domestic waste are films. Moreover, about 615,000 tonnes of agricultural flexible waste are generated in the EU every year. A review of plastic films recycling has been conducted in order to detect the shortcomings and establish guidelines for future research. This paper reviews plastic films waste management technologies from two different sources: post-industrial and post-consumer. Clean and homogeneous post-industrial waste is recycled through closed-loop or open-loop mechanical processes. The main differences between these methods are the quality and the application of the recycled materials. Further research should be focused on closing the loops to obtain the highest environmental benefits of recycling. This could be accomplished through minimizing the material degradation during mechanical processes. Regarding post-consumer waste, flexible films from agricultural and packaging sectors have been assessed. The agricultural films and commercial and industrial flexible packaging are recycled through open-loop mechanical recycling due to existing selective waste collection routes. Nevertheless, the contamination from the use phase adversely affects the quality of recycled plastics. Therefore, upgrading of current washing lines is required. On the other hand, household flexible packaging shows the lowest recycling rates mainly because of inefficient sorting technologies. Delamination and compatibilization methods should be further developed to ensure the recycling of multilayer films. Finally, Life Cycle Assessment (LCA) studies on waste management have been reviewed. A lack of thorough LCA on plastic films waste

78 FR 65007 - Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 3

Science.gov (United States)

2013-10-30

... NUCLEAR REGULATORY COMMISSION [Docket No. 052-00026; NRC-2008-0252] Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 3 AGENCY: Nuclear Regulatory Commission. ACTION: Determination of inspections, tests, analyses, and acceptance criteria completion...

Nurses aged over 50 and their perceptions of flexible working.

Science.gov (United States)

Clendon, Jill; Walker, Léonie

2016-04-01

To explore the experiences and needs of older nurses in relation to flexible working and the barriers and facilitators to implementation within workplaces. An ageing nursing workforce and anticipated nursing workforce shortages require effective approaches to workforce retention. A mixed method approach (focus group and individual interviews) with nurses aged over 50 (n = 46) combined with analysis of district health board (DHB) flexible working policies. Participants had a good understanding of flexible working and recognised the importance of balancing their own needs with those of their organisation. Participants had legitimate reasons for making requests and became frustrated when turned down. They recommended job sharing, shorter shifts, no night shift and greater recognition of their work to improve retention. There was discrepancy between organisational policy (where this existed) and implementation. Organisations should review flexible working policies, ensuring these are understood and implemented at the unit level. Training of nurse managers is recommended. Nurse managers must recognise the individual needs of nurses, be cognisant of workplace policies regarding flexible working, ensure these are implemented consistently and make the effort to recognise the work of older nurses. © 2015 John Wiley & Sons Ltd.

PEDOT as a Flexible Organic Electrode for a Thin Film Acoustic Energy Harvester.

Science.gov (United States)

Kim, Younghoon; Na, Jongbeom; Park, Chihyun; Shin, Haijin; Kim, Eunkyoung

2015-08-05

An efficient thin film acoustic energy harvester was explored using flexible poly(3,4-ethylene dioxythiophene) (PEDOT) films as electrodes in an all-organic triboelectric generator (AO-TEG). A thin film AO-TEG structured as PEDOT/Kapton//PET/PEDOT was prepared by the solution casting polymerization(SCP) on the dielectric polymer films. As-prepared AO-TEG showed high flexibility and durability due to the strong adhesion between the electrodes and the dielectric polymer. The short-circuit current density (Jsc), open-circuit voltage (Voc), and maximum power density (Pw) reached 50 mA/m(2), 700 V, and 12.9 W/m(2) respectively. The output current density decreased with the increase in the electrode resistance (Re), but the energy loss in the organic electrodes was negligible. The AO-TEG could light up 180 LEDs instantaneously upon touching of the AO-TEG with a palm (∼120 N). With the flexible structure, the AO-TEG was worn as clothes and generated electricity to light LEDs upon regular human movement. Furthermore, the AO-TEG was applicable as a thin film acoustic energy harvester, which used music to generate electricity enough for powering of 5 LEDs. An AO-TEG with a PEDOT electrode (Re = 200 Ω) showed instantaneous peak-to-peak voltage generation of 11 V under a sound pressure level (SPL) of 90-100 dB. The harvested acoustic energy through the AO-TEG was 350 μJ from the 4 min playing of the same single song. This is the first demonstration of a flexible triboelectric generator (TEG) using an organic electrode for harvesting acoustic energy from ambient environment.

78 FR 49305 - Luminant Generation Company LLC, Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2...

Science.gov (United States)

2013-08-13

... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-445 and 50-446; NRC-2013-0182] Luminant Generation Company LLC, Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2; Application for Amendment to Facility... Operating License Nos. NPF-87 and NPF-89 for the Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2...

Automatic generation control with thyristor controlled series compensator including superconducting magnetic energy storage units

Directory of Open Access Journals (Sweden)

Saroj Padhan

2014-09-01

Full Text Available In the present work, an attempt has been made to understand the dynamic performance of Automatic Generation Control (AGC of multi-area multi-units thermal–thermal power system with the consideration of Reheat turbine, Generation Rate Constraint (GRC and Time delay. Initially, the gains of the fuzzy PID controller are optimized using Differential Evolution (DE algorithm. The superiority of DE is demonstrated by comparing the results with Genetic Algorithm (GA. After that performance of Thyristor Controlled Series Compensator (TCSC has been investigated. Further, a TCSC is placed in the tie-line and Superconducting Magnetic Energy Storage (SMES units are considered in both areas. Finally, sensitivity analysis is performed by varying the system parameters and operating load conditions from their nominal values. It is observed that the optimum gains of the proposed controller need not be reset even if the system is subjected to wide variation in loading condition and system parameters.

The dual pathway to creativity model: creative ideation as a function of flexibility and persistence

NARCIS (Netherlands)

Nijstad, B.A.; de Dreu, C.K.W.; Rietzschel, E.F.; Baas, M.

2010-01-01

The dual pathway to creativity model argues that creativity—the generation of original and appropriate ideas—is a function of cognitive flexibility and cognitive persistence, and that dispositional or situational variables may influence creativity either through their effects on flexibility, on

The dual pathway to creativity model : Creative ideation as a function of flexibility and persistence

NARCIS (Netherlands)

Nijstad, B.A.; De Dreu, C.K.W.; Rietzschel, E.F.; Baas, M.

2010-01-01

The dual pathway to creativity model argues that creativity-the generation of original and appropriate ideas-is a function of cognitive flexibility and cognitive persistence, and that dispositional or situational variables may influence creativity either through their effects on flexibility, on

78 FR 53483 - Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 3

Science.gov (United States)

2013-08-29

... NUCLEAR REGULATORY COMMISSION [Docket No. 052-00025; NRC-2008-0252] Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 3 AGENCY: Nuclear Regulatory Commission. ACTION: Determination of inspections, tests, analyses, and acceptance criteria (ITAAC) completion...

78 FR 53484 - Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 4

Science.gov (United States)

2013-08-29

... NUCLEAR REGULATORY COMMISSION [Docket No. 052-00026; NRC-2008-0252] Inspections, Tests, Analyses, and Acceptance Criteria; Vogtle Electric Generating Plant, Unit 4 AGENCY: Nuclear Regulatory Commission. ACTION: Determination of inspections, tests, analyses, and acceptance criteria (ITAAC) completion...

Undermining the rules in home care services for the elderly in Norway: flexibility and cooperation.

Science.gov (United States)

Wollscheid, Sabine; Eriksen, John; Hallvik, Jørgen

2013-06-01

This study explores the provision of home care services (home nursing and domiciliary help) for the elderly in Norwegian municipalities with purchaser-provider split model. The study draws on the assumption that flexibility in adjusting services to the care receivers' needs, and cooperation between provider and purchasers are indicators of good quality of care. Data were collected through semi-structured telephone interviews with 22 team leaders of provider units in nine municipalities. Data were collected in 2008-2009. The study has been approved by the Norwegian Social Science Data Services. We identified four different ways of organising home care services under a purchaser-provider split model: Provider empowerment, New Public Management, Vague instructions and undermining the rules. High flexibility in providing care and cooperation with the purchaser unit were identified by the team leaders as characteristics for good care. Our findings suggest that the care providers use individual strategies that allow flexibility and cooperation rather than rigidly abiding to the regulations the purchaser-provider split models implies. Ironically, in provider units where the 'rules were undermined', the informants (team leaders of provider units) seemed to be most satisfied with the quality of home care that they delivered. © 2012 Nordic College of Caring Science.

Imagine There's No Carnegie Unit

Science.gov (United States)

Klevgaard, Janine

2013-01-01

This article describes how the Alberta Education High School Flexibility Enhancement Pilot Project allowed 16 high schools in Alberta, Canada, to remove the restrictions of the Carnegie unit, the seat time per credit requirement that has been widely used since 1906. The two purposes of the project were to determine whether the Carnegie unit should…

Mapping brain activity with flexible graphene micro-transistors

Science.gov (United States)

Blaschke, Benno M.; Tort-Colet, Núria; Guimerà-Brunet, Anton; Weinert, Julia; Rousseau, Lionel; Heimann, Axel; Drieschner, Simon; Kempski, Oliver; Villa, Rosa; Sanchez-Vives, Maria V.; Garrido, Jose A.

2017-06-01

Establishing a reliable communication interface between the brain and electronic devices is of paramount importance for exploiting the full potential of neural prostheses. Current microelectrode technologies for recording electrical activity, however, evidence important shortcomings, e.g. challenging high density integration. Solution-gated field-effect transistors (SGFETs), on the other hand, could overcome these shortcomings if a suitable transistor material were available. Graphene is particularly attractive due to its biocompatibility, chemical stability, flexibility, low intrinsic electronic noise and high charge carrier mobilities. Here, we report on the use of an array of flexible graphene SGFETs for recording spontaneous slow waves, as well as visually evoked and also pre-epileptic activity in vivo in rats. The flexible array of graphene SGFETs allows mapping brain electrical activity with excellent signal-to-noise ratio (SNR), suggesting that this technology could lay the foundation for a future generation of in vivo recording implants.

Next generation non-vacuum, maskless, low temperature nanoparticle ink laser digital direct metal patterning for a large area flexible electronics.

Science.gov (United States)

Yeo, Junyeob; Hong, Sukjoon; Lee, Daehoo; Hotz, Nico; Lee, Ming-Tsang; Grigoropoulos, Costas P; Ko, Seung Hwan

2012-01-01

Flexible electronics opened a new class of future electronics. The foldable, light and durable nature of flexible electronics allows vast flexibility in applications such as display, energy devices and mobile electronics. Even though conventional electronics fabrication methods are well developed for rigid substrates, direct application or slight modification of conventional processes for flexible electronics fabrication cannot work. The future flexible electronics fabrication requires totally new low-temperature process development optimized for flexible substrate and it should be based on new material too. Here we present a simple approach to developing a flexible electronics fabrication without using conventional vacuum deposition and photolithography. We found that direct metal patterning based on laser-induced local melting of metal nanoparticle ink is a promising low-temperature alternative to vacuum deposition- and photolithography-based conventional metal patterning processes. The "digital" nature of the proposed direct metal patterning process removes the need for expensive photomask and allows easy design modification and short turnaround time. This new process can be extremely useful for current small-volume, large-variety manufacturing paradigms. Besides, simple, scalable, fast and low-temperature processes can lead to cost-effective fabrication methods on a large-area polymer substrate. The developed process was successfully applied to demonstrate high-quality Ag patterning (2.1 µΩ·cm) and high-performance flexible organic field effect transistor arrays.

Next generation non-vacuum, maskless, low temperature nanoparticle ink laser digital direct metal patterning for a large area flexible electronics.

Directory of Open Access Journals (Sweden)

Junyeob Yeo

Full Text Available Flexible electronics opened a new class of future electronics. The foldable, light and durable nature of flexible electronics allows vast flexibility in applications such as display, energy devices and mobile electronics. Even though conventional electronics fabrication methods are well developed for rigid substrates, direct application or slight modification of conventional processes for flexible electronics fabrication cannot work. The future flexible electronics fabrication requires totally new low-temperature process development optimized for flexible substrate and it should be based on new material too. Here we present a simple approach to developing a flexible electronics fabrication without using conventional vacuum deposition and photolithography. We found that direct metal patterning based on laser-induced local melting of metal nanoparticle ink is a promising low-temperature alternative to vacuum deposition- and photolithography-based conventional metal patterning processes. The "digital" nature of the proposed direct metal patterning process removes the need for expensive photomask and allows easy design modification and short turnaround time. This new process can be extremely useful for current small-volume, large-variety manufacturing paradigms. Besides, simple, scalable, fast and low-temperature processes can lead to cost-effective fabrication methods on a large-area polymer substrate. The developed process was successfully applied to demonstrate high-quality Ag patterning (2.1 µΩ·cm and high-performance flexible organic field effect transistor arrays.

Timing-based business models for flexibility creation in the electric power sector

International Nuclear Information System (INIS)

Helms, Thorsten; Loock, Moritz; Bohnsack, René

2016-01-01

Energy policies in many countries push for an increase in the generation of wind and solar power. Along these developments, the balance between supply and demand becomes more challenging as the generation of wind and solar power is volatile, and flexibility of supply and demand becomes valuable. As a consequence, companies in the electric power sector develop new business models that create flexibility through activities of timing supply and demand. Based on an extensive qualitative analysis of interviews and industry research in the energy industry, the paper at hand explores the role of timing-based business models in the power sector and sheds light on the mechanisms of flexibility creation through timing. In particular we distill four ideal-type business models of flexibility creation with timing and reveal how they can be classified along two dimensions, namely costs of multiplicity and intervention costs. We put forward that these business models offer ‘coupled services’, combining resource-centered and service-centered perspectives. This complementary character has important implications for energy policy. - Highlights: •Explores timing-based business models providing flexibility in the energy industry. •Timing-based business models can be classified on two dimensions. •Timing-based business models offer ‘coupled services’. • ‘Coupled services’ couple timing as a service with supply- or demand side valuables. •Policy and managerial implications for energy market design.

Major design issues of molten carbonate fuel cell power generation unit

Energy Technology Data Exchange (ETDEWEB)

Chen, T.P.

1996-04-01

In addition to the stack, a fuel cell power generation unit requires fuel desulfurization and reforming, fuel and oxidant preheating, process heat removal, waste heat recovery, steam generation, oxidant supply, power conditioning, water supply and treatment, purge gas supply, instrument air supply, and system control. These support facilities add considerable cost and system complexity. Bechtel, as a system integrator of M-C Power`s molten carbonate fuel cell development team, has spent substantial effort to simplify and minimize these supporting facilities to meet cost and reliability goals for commercialization. Similiar to other fuels cells, MCFC faces design challenge of how to comply with codes and standards, achieve high efficiency and part load performance, and meanwhile minimize utility requirements, weight, plot area, and cost. However, MCFC has several unique design issues due to its high operating temperature, use of molten electrolyte, and the requirement of CO2 recycle.

The impact of liberalization on the scope of efficiency improvement in electricity-generating portfolios for the United States and Switzerland

Energy Technology Data Exchange (ETDEWEB)

Krey, B.; Zweifel, P. [Socioeconomic Institute, Zurich (Switzerland)

2008-09-15

In this study, Markowitz mean-variance portfolio theory is applied to electricity-generating technologies of the United States and Switzerland. Both an investor (focused on changes in return) and a current user (focused on return in levels) view are adopted to determine efficient frontiers of electricity generation technologies in terms of expected return and risk as of 2003. Since shocks in generation costs per kWh (the inverse of returns) are correlated, Seemingly Unrelated Regression Estimation (SURE) is used to filter out the systematic components of the covariance matrix. Results suggest that risk-averse investors and risk-neutral current users in the United States are considerably closer to their efficiency frontier than their Swiss counterparts. This may be due to earlier and more thorough deregulation of electricity markets in the United States. (orig.)

The relation between flexibility of human resources and performance indexes of selected hospitals of Tehran Medical Sciences University

Directory of Open Access Journals (Sweden)

Noushin Alibakhshi

2016-12-01

Full Text Available Today, flexibility has turned to one of important issues in management theories and policies and most current discussions about flexibility patterns focus on management policies, so that these patterns are one of important aspects of human resources strategic management. This study was performed with the aim of assessing the flexibility rate of human resources and performance indexes of Tehran Medical Sciences University hospitals and determining the possible relation between these variables. The present study is descriptive – analytical which was conducted in cross-sectional form in 2015. The statistical population was selected by stratifies random sampling method as 317 persons from nursing, administrative and financial personnel of 5 hospitals of Tehran Medical Sciences University. Data collecting toll was hospitals performance indexes form and Wright & Snell flexibility questionnaire of human resources. Data analysis was performed using SPSS 18 software and with the aid of descriptive statistical indexes and linear regression analysis. The results showed that personnel ( human resources had high flexibility = 4.16.\tthere was a significant relation between total flexibility and the index of bed circulation so that by one unit increase in bed circulation space, normally, the average of total flexibility decreased 0.64 units ( p-value<0.05. The results showed that human resources of Tehran Medical Sciences University hospitals have high flexibility, so authorities and policy makers are suggested to adopt policies of human resources management for creating flexibility in human resources and improving hospitals performance and amending hospitals status.

Comparison of ICEPEL predictions with single elbow flexible piping system experiment

International Nuclear Information System (INIS)

A-Moneim, M.T.; Chang, Y.W.

1978-01-01

The ICEPEL Code for coupled hydrodynamic-structural response analysis of piping systems is used to analyze an experiment on the response of flexible piping systems to internal pressure pulses. The piping system consisted of two flexible Nickel-200 pipes connected in series through a 90 0 thick-walled stainless steel elbow. A tailored pressure pulse generated by a calibrated pulse gun is stabilized in a long thick-walled stainless steel pipe leading to the flexible piping system which ended with a heavy blind flange. The analytical results of pressure and circumferential strain histories are discussed and compared against the experimental data obtained by Stanford Research Institute

An examination of electricity generation by utility organizations in the Southeast United States

International Nuclear Information System (INIS)

Craig, Christopher A.; Feng, Song

2016-01-01

This study examined the impact of climatic variability on electricity generation in the Southeast United States. The relationship cooling degree days (CDD) and heating degree days (HDD) shared with electricity generation by fuel source was explored. Using seasonal autoregressive integrated weighted average (ARIMA) and seasonal simple exponentially smoothed models, retrospective time series analysis was run. The hypothesized relationship between climatic variability and total electricity generation was supported, where an ARIMA model including CDDs as a predictor explained 57.6% of the variability. The hypothesis that climatic variability would be more predictive of fossil fuel electricity generation than electricity produced by clean energy sources was partially supported. The ARIMA model for natural gas indicated that CDDS were the only predictor for the fossil fuel source, and that 79.4% of the variability was explained. Climatic variability was not predictive of electricity generation from coal or petroleum, where simple seasonal exponentially smoothed models emerged. However, HDDs were a positive predictor of hydroelectric electricity production, where 48.9% of the variability in the clean energy source was explained by an ARIMA model. Implications related to base load electricity from fossil fuels, and future electricity generation projections relative to extremes and climate change are discussed. - Highlights: • Models run to examine impact of climatic variability on electricity generation. • Cooling degree days explained 57.6% of variability in total electricity generation. • Climatic variability was not predictive of coal or petroleum generation. • Cooling degree days explained 79.4% of natural gas generation. • Heating degree days were predictive of nuclear and hydroelectric generation.

Fluid elastic instability tests on an array of tubes preferentially flexible in the flow direction

International Nuclear Information System (INIS)

Mureithi, N.W.; Zhang, C.; Pettigrew, M.J.

2004-01-01

The present work is motivated by the observation that, in the presence of flat bar supports (AVBs), U-tubes in steam generators and heat exchangers are not positively restrained in the in-plane direction. The stability behavior of a rotated triangular array is investigated in detail in the work presented here. Tubes within the array are flexible only in the flow direction. Tests are conducted with a fully flexible array, a single flexible tube, and a finite number of flexible tubes at several locations within the otherwise rigid array. In all cases tube flexibility is purely in the flow direction. The fully flexible array is shown to undergo fluid-elastic instability. Despite the unidirectional flexibility constraint, the critical instability velocity is of the same order of magnitude when compared with previous tests on an unconstrained fully flexible array. A single flexible tube, on the other hand, is found to be stable. Results of tests on partially flexible array configurations are also presented. (authors)

Suspicious spirits, flexible minds: when distrust enhances creativity.

Science.gov (United States)

Mayer, Jennifer; Mussweiler, Thomas

2011-12-01

Intuitively, as well as in light of prior research, distrust and creativity appear incompatible. The social consequences of distrust include reluctance to share information, a quality detrimental to creativity in social settings. At the same time, the cognitive concomitants of distrust bear resemblance to creative cognition: Distrust seems to foster thinking about nonobvious alternatives to potentially deceptive appearances. These cognitive underpinnings of distrust hold the provocative implication that distrust may foster creativity. Mirroring these contradictory findings, we suggest that the social versus cognitive consequences of distrust have diverging implications for creativity. We address this question in Study 1 by introducing private/public as a moderating variable for effects of distrust on creativity. Consistent with distrust's social consequences, subliminal distrust (vs. trust) priming had detrimental effects on creative generation presumed to be public. Consistent with distrust's cognitive consequences, though, an opposite tendency emerged in private. Study 2 confirmed a beneficial effect of distrust on private creative generation with a different priming method and pointed to cognitive flexibility as the mediating process. Studies 3 and 4 showed increased category inclusiveness versus increased remote semantic spread after distrust priming, consistent with enhanced cognitive flexibility as a consequence of distrust. Taken together, these results provide evidence for the creativity-enhancing potential of distrust and suggest cognitive flexibility as its underlying mechanism.

The influence of flexible branches in flexible polymers

International Nuclear Information System (INIS)

Wescott, J.T.

1998-06-01

In this work the influence of branches in flexible polymer systems has been investigated by consideration of (1) the behaviour of isolated poly-α-olefin chains and (2) the p -T phase behaviour of poly(4-methylpentene-1)(P4MP1). Molecular dynamics simulations of isolated poly-α-olefins were performed in order to gauge directly the effect of molecular structure on chain dimensions, flexibility (via the persistence length) and shape. Under Θ-conditions the addition of short linear branches was shown to increase the flexibility of the backbone. In conditions of good solvent, however, the effect of longer and bulkier branches was to increase the persistence length and average size of the coil with the arrangement of side chain atoms making a small difference. The side branches themselves also affected the solvent conditions experienced by the backbone, behaving much like bound solvent. Consideration of ethylene-α-olefin copolymers, where the branch content was varied from 0-50%, showed that under good solvent conditions the branches increased the chain stiffness only when the gap between side branches was less than five backbone carbon atoms. The backbone torsions were also shown to play an important role in determining these trends. For comparison with the above simulations, persistence length values for polyethylene (= 7.3±0.2A) and P4MP1 (=7.6±0.3A) were measured experimentally by neutron scattering in dilute solution. A value of 6.7±0.5 for the characteristic ratio of PE was also calculated. To investigate the role of a bulky side group in crystalline phases, wide angle X-ray diffraction experiments using a Hikosaka pressure cell were performed on P4MP1. Computer modelling, utilising the experimental data obtained, determined the structure of a disordered phase produced at room temperature and a new high pressure/high temperature phase. The disordered phase was found to be due to a collapse of the backbone combined with some disordering of the side chains

Effects of a pilates school program on hamstrings flexibility of adolescents

Directory of Open Access Journals (Sweden)

Noelia González-Gálvez

2015-08-01

Full Text Available INTRODUCTION: Low levels of hamstring flexibility may trigger certain acute and chronic pathologies and injuries. Poor flexibility is observed among teenagers and several authors have recommended the use of specific programs in this population to improve flexibility levels. The Pilates Method (PM may be an appropriate intervention to achieve this purpose and has rarely been used with this population. Objective: Study was to assess changes in the flexibility of hamstrings after running a didactic PM unit for high-school students.METHODS: This research was developed through a quasi-experimental design. The sample consisted of 66 high-school students divided into experimental group (EG=39 and control group (CG=27. The intervention was carried out 2 times a week for six weeks. Each session lasted 55 minutes divided into three parts: warm-up, main part and cool down. Hamstring flexibility was assessed using the toe-touch test. Paired Student t-test and t-test for independent samples were applied. The size of the effect (d was determined.RESULTS: The EG showed significant provident in hamstring flexibility (+3.54±3.9cm. The effect size was low (d>d>0,2d>0.21.15 which means that a large proportion of participants improved their results.CONCLUSION: This study showed that six-weeks of Pilates training in Physical Education classes has significantly improved the hamstrings flexibility among adolescents.

Office flexible cystoscopy.

Science.gov (United States)

Kavoussi, L R; Clayman, R V

1988-11-01

Since the development of the first purpose-built flexible cystoscope in 1984, flexible cystoscopy has become an accepted diagnostic and therapeutic modality. Indeed, it is estimated that more than 10 per cent of practicing urologists are already familiar with this technology. The flexible cystoscope has markedly extended the urologist's ability to examine the bladder, and it has become a valuable adjunct to the rigid cystoscope. Although the operation of this instrument is vastly different from that of its rigid counterpart, with practice, the technique can be learned. After experience is obtained with diagnostic flexible cystoscopy, the urologist will likely prefer this new instrument for bladder inspection, as it provides for a more thorough yet less morbid and less expensive examination. In the future, the development of improved and smaller instrumentation will further extend the therapeutic indications for flexible cystoscopy. Indeed, advances in laser technology are already providing the urologist with 300- to 600-micron (0.9 to 1.8F) flexible probes capable of incision (KTP laser), fulguration (Nd:YAG laser), and stone disintegration (tunable dye laser). Lastly, the skills obtained in using the flexible cystoscope are all readily applicable to the development of dexterity with the already available flexible nephroscope and the more recently developed flexible ureteroscope.

Design and Testing of a Flexible Inclinometer Probe for Model Tests of Landslide Deep Displacement Measurement.

Science.gov (United States)

Zhang, Yongquan; Tang, Huiming; Li, Changdong; Lu, Guiying; Cai, Yi; Zhang, Junrong; Tan, Fulin

2018-01-14

The physical model test of landslides is important for studying landslide structural damage, and parameter measurement is key in this process. To meet the measurement requirements for deep displacement in landslide physical models, an automatic flexible inclinometer probe with good coupling and large deformation capacity was designed. The flexible inclinometer probe consists of several gravity acceleration sensing units that are protected and positioned by silicon encapsulation, all the units are connected to a 485-comunication bus. By sensing the two-axis tilt angle, the direction and magnitude of the displacement for a measurement unit can be calculated, then the overall displacement is accumulated according to all units, integrated from bottom to top in turn. In the conversion from angle to displacement, two spline interpolation methods are introduced to correct and resample the data; one is to interpolate the displacement after conversion, and the other is to interpolate the angle before conversion; compared with the result read from checkered paper, the latter is proved to have a better effect, with an additional condition that the displacement curve move up half the length of the unit. The flexible inclinometer is verified with respect to its principle and arrangement by a laboratory physical model test, and the test results are highly consistent with the actual deformation of the landslide model.

Integration of renewable generation uncertainties into stochastic unit commitment considering reserve and risk: A comparative study

International Nuclear Information System (INIS)

Quan, Hao; Srinivasan, Dipti; Khosravi, Abbas

2016-01-01

The uncertainties of renewable energy have brought great challenges to power system commitment, dispatches and reserve requirement. This paper presents a comparative study on integration of renewable generation uncertainties into SCUC (stochastic security-constrained unit commitment) considering reserve and risk. Renewable forecast uncertainties are captured by a list of PIs (prediction intervals). A new scenario generation method is proposed to generate scenarios from these PIs. Different system uncertainties are considered as scenarios in the stochastic SCUC problem formulation. Two comparative simulations with single (E1: wind only) and multiple sources of uncertainty (E2: load, wind, solar and generation outages) are investigated. Five deterministic and four stochastic case studies are performed. Different generation costs, reserve strategies and associated risks are compared under various scenarios. Demonstrated results indicate the overall costs of E2 is lower than E1 due to penetration of solar power and the associated risk in deterministic cases of E2 is higher than E1. It implies the superimposed effect of uncertainties during uncertainty integration. The results also demonstrate that power systems run a higher level of risk during peak load hours, and that stochastic models are more robust than deterministic ones. - Highlights: • An extensive comparative study for renewable integration is presented. • A novel scenario generation method is proposed. • Wind and solar uncertainties are represented by a list of prediction intervals. • Unit commitment and dispatch costs are discussed considering reserve and risk.

Replacement energy costs for nuclear electricity-generating units in the United States: 1997--2001. Volume 4

International Nuclear Information System (INIS)

VanKuiken, J.C.; Guziel, K.A.; Tompkins, M.M.; Buehring, W.A.

1997-09-01

This report updates previous estimates of replacement energy costs for potential short-term shutdowns of 109 US nuclear electricity-generating units. This information was developed to assist the US Nuclear Regulatory Commission (NRC) in its regulatory impact analyses, specifically those that examine the impacts of proposed regulations requiring retrofitting of or safety modifications to nuclear reactors. Such actions might necessitate shutdowns of nuclear power plants while these changes are being implemented. The change in energy cost represents one factor that the NRC must consider when deciding to require a particular modification. Cost estimates were derived from probabilistic production cost simulations of pooled utility system operations. Factors affecting replacement energy costs, such as random unit failures, maintenance and refueling requirements, and load variations, are treated in the analysis. This report describes an abbreviated analytical approach as it was adopted to update the cost estimates published in NUREG/CR-4012, Vol. 3. The updates were made to extend the time frame of cost estimates and to account for recent changes in utility system conditions, such as change in fuel prices, construction and retirement schedules, and system demand projects

Flexible work schedules, older workers, and retirement.

Science.gov (United States)

Siegenthaler, J K; Brenner, A M

2000-01-01

Older workers in the United States indicate that they would prefer flexible work arrangements rather than abrupt retirement, yet management has done very little to make this possible. A review of two bodies of literature from the late 1980s is presented: social science writings including sociological, gerontological, and economic literature, and business and management literature. There is a clash between the way jobs are traditionally scheduled and the needs of growing numbers of older workers. Workers continue to be subject to obstacles to phased retirement due to the structuring of health care and pension benefits, downsizing, organizational inflexibility, and "corporate culture." Thus, general views among social scientists regarding the desirability of flexible schedules toward retirement will not produce real changes unless management becomes committed to such changes and they are securely embedded in company policies.

New flexible endoscope for otologic application

Science.gov (United States)

Marchan, Mark L.

1993-07-01

Endoscopy has become an important procedure in many medical specialties. For the Otologist, however, space limitations within the ear have restricted development of endoscopic procedures. The desire for minimally invasive techniques in Otology has demonstrated itself through the work of numerous physicians who have performed procedures ranging from diagnostic inspection of the middle ear to viewing the interior of the cochlea. To assist in performing such endoscopic procedures, Xomed-Treace has developed a line of flexible fiberoptic endoscopes for use by the Otologist. These scopes combine illumination and imaging fiber bundles within a small diameter unit ranging in size from 0.8 mm to 1.2 mm. The 1.2 mm scope is produced with an angled, rigid stainless steel sheath. The 0.8 mm scope is flexible with the ability to articulate 120 degree(s) in one direction. The fiberscopes have been designed for the Otologist to produce a good resolution image while allowing ease of operation through ergonomics and consideration of the surgical anatomy.

Advanced power generation systems for the 21st Century: Market survey and recommendations for a design philosophy

Energy Technology Data Exchange (ETDEWEB)

Andriulli, J.B.; Gates, A.E.; Haynes, H.D.; Klett, L.B.; Matthews, S.N.; Nawrocki, E.A.; Otaduy, P.J.; Scudiere, M.B.; Theiss, T.J.; Thomas, J.F.; Tolbert, L.M.; Yauss, M.L.; Voltz, C.A.

1999-11-01

The purpose of this report is to document the results of a study designed to enhance the performance of future military generator sets (gen-sets) in the medium power range. The study includes a market survey of the state of the art in several key component areas and recommendations comprising a design philosophy for future military gen-sets. The market survey revealed that the commercial market is in a state of flux, but it is currently or will soon be capable of providing the technologies recommended here in a cost-effective manner. The recommendations, if implemented, should result in future power generation systems that are much more functional than today's gen-sets. The number of differing units necessary (both family sizes and frequency modes) to cover the medium power range would be decreased significantly, while the weight and volume of each unit would decrease, improving the transportability of the power source. Improved fuel economy and overall performance would result from more effective utilization of the prime mover in the generator. The units would allow for more flexibility and control, improved reliability, and more effective power management in the field.

Flexible Aqueous Lithium-Ion Battery with High Safety and Large Volumetric Energy Density.

Science.gov (United States)

Dong, Xiaoli; Chen, Long; Su, Xiuli; Wang, Yonggang; Xia, Yongyao

2016-06-20

A flexible and wearable aqueous lithium-ion battery is introduced based on spinel Li1.1 Mn2 O4 cathode and a carbon-coated NASICON-type LiTi2 (PO4 )3 anode (NASICON=sodium-ion super ionic conductor). Energy densities of 63 Wh kg(-1) or 124 mWh cm(-3) and power densities of 3 275 W kg(-1) or 11.1 W cm(-3) can be obtained, which are seven times larger than the largest reported till now. The full cell can keep its capacity without significant loss under different bending states, which shows excellent flexibility. Furthermore, two such flexible cells in series with an operation voltage of 4 V can be compatible with current nonaqueous Li-ion batteries. Therefore, such a flexible cell can potentially be put into practical applications for wearable electronics. In addition, a self-chargeable unit is realized by integrating a single flexible aqueous Li-ion battery with a commercial flexible solar cell, which may facilitate the long-time outdoor operation of flexible and wearable electronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High performance flexible CMOS SOI FinFETs

KAUST Repository

Fahad, Hossain M.

2014-06-01

We demonstrate the first ever CMOS compatible soft etch back based high performance flexible CMOS SOI FinFETs. The move from planar to non-planar FinFETs has enabled continued scaling down to the 14 nm technology node. This has been possible due to the reduction in off-state leakage and reduced short channel effects on account of the superior electrostatic charge control of multiple gates. At the same time, flexible electronics is an exciting expansion opportunity for next generation electronics. However, a fully integrated low-cost system will need to maintain ultra-large-scale-integration density, high performance and reliability - same as today\\'s traditional electronics. Up until recently, this field has been mainly dominated by very weak performance organic electronics enabled by low temperature processes, conducive to low melting point plastics. Now however, we show the world\\'s highest performing flexible version of 3D FinFET CMOS using a state-of-the-art CMOS compatible fabrication technique for high performance ultra-mobile consumer applications with stylish design. © 2014 IEEE.

A fast method for the unit scheduling problem with significant renewable power generation

International Nuclear Information System (INIS)

Osório, G.J.; Lujano-Rojas, J.M.; Matias, J.C.O.; Catalão, J.P.S.

2015-01-01

Highlights: • A model to the scheduling of power systems with significant renewable power generation is provided. • A new methodology that takes information from the analysis of each scenario separately is proposed. • Based on a probabilistic analysis, unit scheduling and corresponding economic dispatch are estimated. • A comparison with others methodologies is in favour of the proposed approach. - Abstract: Optimal operation of power systems with high integration of renewable power sources has become difficult as a consequence of the random nature of some sources like wind energy and photovoltaic energy. Nowadays, this problem is solved using Monte Carlo Simulation (MCS) approach, which allows considering important statistical characteristics of wind and solar power production such as the correlation between consecutive observations, the diurnal profile of the forecasted power production, and the forecasting error. However, MCS method requires the analysis of a representative amount of trials, which is an intensive calculation task that increases considerably with the number of scenarios considered. In this paper, a model to the scheduling of power systems with significant renewable power generation based on scenario generation/reduction method, which establishes a proportional relationship between the number of scenarios and the computational time required to analyse them, is proposed. The methodology takes information from the analysis of each scenario separately to determine the probabilistic behaviour of each generator at each hour in the scheduling problem. Then, considering a determined significance level, the units to be committed are selected and the load dispatch is determined. The proposed technique was illustrated through a case study and the comparison with stochastic programming approach was carried out, concluding that the proposed methodology can provide an acceptable solution in a reduced computational time

Real-Time Congestion Management in Distribution Networks by Flexible Demand Swap

DEFF Research Database (Denmark)

Huang, Shaojun; Wu, Qiuwei

2017-01-01

In addition to the day-ahead congestion management in distribution networks, the real-time congestion management is very important because many unforeseen events can occur at the real operation time, e.g. loss of generation of distributed energy resources (DERs) or inaccurate forecast of energy...... pumps (HPs) for real time congestion management. The swap method can maintain the power balance of the system and avoid the imbalance cost of activating the flexibility service. An algorithm for forming swaps through optimal power flow (OPF) and mixed integer linear programming (MILP) is proposed...... consumption or production. Flexibility service from demand will be a good option to solve the real-time congestions if the cost of activating the flexibility service is fully addressed. This paper proposes a new method, namely “swap”, to employ the flexibility service from electric vehicles (EVs) and heat...

Impact of Flexibility Options on Grid Economic Carrying Capacity of Solar and Wind: Three Case Studies

Energy Technology Data Exchange (ETDEWEB)

Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Novacheck, Joshua [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); O' Connell, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-12-01

In this study, we attempt to quantify the benefits of various options of grid flexibility by measuring their impact on two measures: economic carrying capacity and system costs. Flexibility can increase ECC and reduce overall system costs. In some cases, options that provide a limited increase in ECC can provide significant operational savings, thus demonstrating the need to evaluate flexibility options using multiple metrics. The value of flexibility options varies regionally due to different generation mixes and types of renewables. The more rapid decline in PV value compared to wind makes PV more dependent on adding flexibility options, including transmission and energy storage.

Regulatory Barriers for Flexible Coupling of the Nordic Power and District Heating Markets

DEFF Research Database (Denmark)

Skytte, Klaus; Olsen, Ole Jess

2016-01-01

that the choice of technologies for heat generation is mainly driven by outdated policies and tax conditions that create barriers for additional flexibility in the overall energy system. However, the balancing markets may be a main driver for introducing more electric boilers into DH and thereby increase its......Large share of variable renewable energy sources (VRE) is being deployed in the Nordic countries, especially wind power. This calls for additional flexibility of the power market. With the right coupling to the underlying national and local district heating (DH) markets, large shares of flexibility...

Optimal placement and sizing of multiple distributed generating units in distribution

Directory of Open Access Journals (Sweden)

D. Rama Prabha

2016-06-01

Full Text Available Distributed generation (DG is becoming more important due to the increase in the demands for electrical energy. DG plays a vital role in reducing real power losses, operating cost and enhancing the voltage stability which is the objective function in this problem. This paper proposes a multi-objective technique for optimally determining the location and sizing of multiple distributed generation (DG units in the distribution network with different load models. The loss sensitivity factor (LSF determines the optimal placement of DGs. Invasive weed optimization (IWO is a population based meta-heuristic algorithm based on the behavior of weeds. This algorithm is used to find optimal sizing of the DGs. The proposed method has been tested for different load models on IEEE-33 bus and 69 bus radial distribution systems. This method has been compared with other nature inspired optimization methods. The simulated results illustrate the good applicability and performance of the proposed method.

Architecture of cognitive flexibility revealed by lesion mapping

Science.gov (United States)

Barbey, Aron K.; Colom, Roberto; Grafman, Jordan

2013-01-01

Neuroscience has made remarkable progress in understanding the architecture of human intelligence, identifying a distributed network of brain structures that support goal-directed, intelligent behavior. However, the neural foundations of cognitive flexibility and adaptive aspects of intellectual function remain to be well characterized. Here, we report a human lesion study (n = 149) that investigates the neural bases of key competencies of cognitive flexibility (i.e., mental flexibility and the fluent generation of new ideas) and systematically examine their contributions to a broad spectrum of cognitive and social processes, including psychometric intelligence (Wechsler Adult Intelligence Scale), emotional intelligence (Mayer, Salovey, Caruso Emotional Intelligence Test), and personality (Neuroticism–Extraversion–Openness Personality Inventory). Latent variable modeling was applied to obtain error-free indices of each factor, followed by voxel-based lesion-symptom mapping to elucidate their neural substrates. Regression analyses revealed that latent scores for psychometric intelligence reliably predict latent scores for cognitive flexibility (adjusted R2 = 0.94). Lesion mapping results further indicated that these convergent processes depend on a shared network of frontal, temporal, and parietal regions, including white matter association tracts, which bind these areas into an integrated system. A targeted analysis of the unique variance explained by cognitive flexibility further revealed selective damage within the right superior temporal gyrus, a region known to support insight and the recognition of novel semantic relations. The observed findings motivate an integrative framework for understanding the neural foundations of adaptive behavior, suggesting that core elements of cognitive flexibility emerge from a distributed network of brain regions that support specific competencies for human intelligence. PMID:23721727

A multi-period, multi-regional generation expansion planning model incorporating unit commitment constraints

International Nuclear Information System (INIS)

Koltsaklis, Nikolaos E.; Georgiadis, Michael C.

2015-01-01

Highlights: • A short-term structured investment planning model has been developed. • Unit commitment problem is incorporated into the long-term planning horizon. • Inherent intermittency of renewables is modelled in a comprehensive way. • The impact of CO_2 emission pricing in long-term investment decisions is quantified. • The evolution of system’s marginal price is evaluated for all the planning horizon. - Abstract: This work presents a generic mixed integer linear programming (MILP) model that integrates the unit commitment problem (UCP), i.e., daily energy planning with the long-term generation expansion planning (GEP) framework. Typical daily constraints at an hourly level such as start-up and shut-down related decisions (start-up type, minimum up and down time, synchronization, soak and desynchronization time constraints), ramping limits, system reserve requirements are combined with representative yearly constraints such as power capacity additions, power generation bounds of each unit, peak reserve requirements, and energy policy issues (renewables penetration limits, CO_2 emissions cap and pricing). For modelling purposes, a representative day (24 h) of each month over a number of years has been employed in order to determine the optimal capacity additions, electricity market clearing prices, and daily operational planning of the studied power system. The model has been tested on an illustrative case study of the Greek power system. Our approach aims to provide useful insight into strategic and challenging decisions to be determined by investors and/or policy makers at a national and/or regional level by providing the optimal energy roadmap under real operating and design constraints.

Flexible structured high-frequency film bulk acoustic resonator for flexible wireless electronics

International Nuclear Information System (INIS)

Zhou, Changjian; Shu, Yi; Yang, Yi; Ren, Tian-Ling; Jin, Hao; Dong, Shu-Rong; Chan, Mansun

2015-01-01

Flexible electronics have inspired many novel and very important applications in recent years and various flexible electronic devices such as diodes, transistors, circuits, sensors, and radiofrequency (RF) passive devices including antennas and inductors have been reported. However, the lack of a high-performance RF resonator is one of the key bottlenecks to implement flexible wireless electronics. In this study, for the first time, a novel ultra-flexible structured film bulk acoustic resonator (FBAR) is proposed. The flexible FBAR is fabricated on a flexible polyimide substrate using piezoelectric thin film aluminum nitride (AlN) for acoustic wave excitation. Both the shear wave and longitudinal wave can be excited under the surface interdigital electrodes configuration we proposed. In the case of the thickness extension mode, a flexible resonator with a working frequency as high as of 5.2325 GHz has been realized. The resonators stay fully functional under bending status and after repeated bending and re-flattening operations. This flexible high-frequency resonator will serve as a key building block for the future flexible wireless electronics, greatly expanding the application scope of flexible electronics. (paper)

Convex modeling and optimization of a vehicle powertrain equipped with a generator-turbine throttle unit

NARCIS (Netherlands)

Marinkov, S.; Murgovski, N.; de Jager, A.G.

2017-01-01

This paper investigates an internal combustion (gasoline) engine throttled by a generator-turbine unit. Apart from throttling, the purpose of this device is to complement the operation of a conventional car alternator and support its downsizing by introducing an additional source of energy for the

Measuring Carbon Footprint of Flexible Pavement Construction Project in Indonesia

Directory of Open Access Journals (Sweden)

Utomo Dwi Hatmoko Jati

2018-01-01

Full Text Available Road infrastructure in Indonesia is mainly dominated by flexible pavement type. Its construction process, however, has raised concerns in terms of its environment impacts. This study aims to track and measure the carbon footprint of flexible pavement. The objectives are to map the construction process in relation to greenhouse gas (GHG emissions, to quantify them in terms of carbon dioxide equivalents (CO2e as generated by the process of production and transportation of raw materials, and the operation of plant off-site and on-site project. Data collection was done by having site observations and interviews with project stakeholders. The results show a total emissions of 70.888 tonnes CO2e, consisting of 34.248 tonnes CO2e (48.31% off-site activities and 36.640 tonnes CO2e (51.687% on-site activities. The two highest CO2e emissions were generated by the use of plant for asphalt concrete laying activities accounted 34.827 tonnes CO2e (49.130%, and material transportation accounted 24.921 (35.155%. These findings provide a new perspective of the carbon footprint in flexible pavement and suggest the urgent need for the use of more efficient and environmentally friendly plant in construction process as it shows the most significant contribution on the CO2e. This study provides valuable understanding on the environmental impact of typical flexible pavement projects in Indonesia, and further can be used for developing green road framework.

Measuring Carbon Footprint of Flexible Pavement Construction Project in Indonesia

Science.gov (United States)

Hatmoko, Jati Utomo Dwi; Hidayat, Arif; Setiawati, Apsari; Prasetyo, Stefanus Catur Adi

2018-02-01

Road infrastructure in Indonesia is mainly dominated by flexible pavement type. Its construction process, however, has raised concerns in terms of its environment impacts. This study aims to track and measure the carbon footprint of flexible pavement. The objectives are to map the construction process in relation to greenhouse gas (GHG) emissions, to quantify them in terms of carbon dioxide equivalents (CO2e) as generated by the process of production and transportation of raw materials, and the operation of plant off-site and on-site project. Data collection was done by having site observations and interviews with project stakeholders. The results show a total emissions of 70.888 tonnes CO2e, consisting of 34.248 tonnes CO2e (48.31%) off-site activities and 36.640 tonnes CO2e (51.687%) on-site activities. The two highest CO2e emissions were generated by the use of plant for asphalt concrete laying activities accounted 34.827 tonnes CO2e (49.130%), and material transportation accounted 24.921 (35.155%). These findings provide a new perspective of the carbon footprint in flexible pavement and suggest the urgent need for the use of more efficient and environmentally friendly plant in construction process as it shows the most significant contribution on the CO2e. This study provides valuable understanding on the environmental impact of typical flexible pavement projects in Indonesia, and further can be used for developing green road framework.

Workplace Flexibility Practices in SMEs: Relationship with Performance via Redundancies, Absenteeism, and Financial Turnover

OpenAIRE

Whyman, Philip B; Petrescu, Alina

2015-01-01

This workplace flexibility study uses primary data on private sector small and medium-sized enterprises (SMEs) in Lancashire, United Kingdom, collected in 2009 during the recent “credit crunch” recession. Key features include: (1) objective measures of SME performance; (2) a focus on the previously relatively neglected relationship between workplace flexibility practices (WFPs) and three SME performance indicators, namely, redundancies, absenteeism, and financial turnover; and (3) a timely co...

The U.S. Strategic Flexibility Policy: Prospects for the U.S.-ROK Alliance

National Research Council Canada - National Science Library

Oh, Soonkun

2006-01-01

.... With the United States and South Korea's recent agreement on the strategic flexibility of USFK, it became obvious that the primary role of the USFK will be changed from North Korean deterrence...

Flexibilization of methanization units in Germany. Overview of technical approaches, of the regulatory framework, and of the importance for the energy system - Synthesis note

International Nuclear Information System (INIS)

Trommler, Marcus; Dotzauer, Martin; Barchmann, Tino; Lauer, Markus; Hennig, Christiane; Mauky, Eric; Liebetrau, Jan; Thraen, Daniela; Risler, Julian

2016-03-01

Technologies of valorisation of biomass offer opportunities to produce a flexible and renewable energy suitable to compensate the intermittency of wind and solar energies which depend on meteorological conditions. As methanization units operated in a flexible way are now mainly present in Germany, notably due to public financial supports to flexibility, this publication describes the status of flexibilization in German methanization units, and highlights relationships with the electricity system, technical approaches to flexibility (implemented technology, gas valorisation in biomethane and injection in the natural gas network, adjustment of gas production for supply management, methanization units and hybrid concepts), and incentive policy (flexibility premium, marketing strategy). The publication finally discusses perspectives for these flexible methanization units

Robust path planning for flexible needle insertion using Markov decision processes.

Science.gov (United States)

Tan, Xiaoyu; Yu, Pengqian; Lim, Kah-Bin; Chui, Chee-Kong

2018-05-11

Flexible needle has the potential to accurately navigate to a treatment region in the least invasive manner. We propose a new planning method using Markov decision processes (MDPs) for flexible needle navigation that can perform robust path planning and steering under the circumstance of complex tissue-needle interactions. This method enhances the robustness of flexible needle steering from three different perspectives. First, the method considers the problem caused by soft tissue deformation. The method then resolves the common needle penetration failure caused by patterns of targets, while the last solution addresses the uncertainty issues in flexible needle motion due to complex and unpredictable tissue-needle interaction. Computer simulation and phantom experimental results show that the proposed method can perform robust planning and generate a secure control policy for flexible needle steering. Compared with a traditional method using MDPs, the proposed method achieves higher accuracy and probability of success in avoiding obstacles under complicated and uncertain tissue-needle interactions. Future work will involve experiment with biological tissue in vivo. The proposed robust path planning method can securely steer flexible needle within soft phantom tissues and achieve high adaptability in computer simulation.

Method and apparatus for preventing inadvertent criticality in a nuclear fueled electric power generating unit

International Nuclear Information System (INIS)

Tuley, C.R.; Bauman, D.A.; Neuner, J.A.; Feilchenfeld, M.M.; Greenberg, L.

1984-01-01

An inadvertent approach to criticality in a nuclear fueled electric power generating unit is detected and an alarm is generated through on-line monitoring of the neutron flux. The difficulties of accurately measuring the low levels of neutron flux in a subcritical reactor are overcome by the use of a microcomputer which continuously generates average flux count rate signals for incremental time periods from thousands of samples taken during each such period and which serially stores the average flux count rate signals for a preselected time interval. At the end of each incremental time period, the microcomputer compares the latest average flux count rate signal with the oldest, and preferably each of the intervening stored values, and if it exceeds any of them by at least a preselected multiplication factor, an alarm is generated. (author)

Mexican Ancestry, Immigrant Generation, and Educational Attainment in the United States

Directory of Open Access Journals (Sweden)

Stephen L. Morgan

2014-09-01

Full Text Available After introducing alternative perspectives on assimilation and acculturation, we use the 2002-2012 waves of the Education Longitudinal Study to model differences in educational attainment for students sampled as high school sophomores in 2002. We focus on patterns observed for the growing Mexican immigrant population, analyzing separately the trajectories of 1st, 1.5th, 2nd, and 3rd+ generation Mexican immigrant students, in comparison to 3rd+ generation students who self-identify as non-Hispanic whites and students who self-identify as non-Hispanic blacks or African Americans. The results suggest that the dissonant acculturation mechanism associated with the segmented assimilation perspective is mostly unhelpful for explaining patterns of educational attainment, especially for the crucial groups of 1.5th and 2nd generation Mexican immigrant students. Instead, standard measures of family background can account for large portions of group differences in bachelor’s degree attainment, with or without additional adjustments for behavioral commitment to schooling, occupational plans, and educational expectations. The broad structure of inequality in the United States, as well as the rising costs of bachelor’s degrees, should be the primary source of concern when considering the prospects for the incorporation of the children of recent Mexican immigrants into the mainstream.

Key thrusts in next generation CANDU. Annex 10

International Nuclear Information System (INIS)

Shalaby, B.A.; Torgerson, D.F.; Duffey, R.B.

2002-01-01

Current electricity markets and the competitiveness of other generation options such as CCGT have influenced the directions of future nuclear generation. The next generation CANDU has used its key characteristics as the basis to leap frog into a new design featuring improved economics, enhanced passive safety, enhanced operability and demonstrated fuel cycle flexibility. Many enabling technologies spinning of current CANDU design features are used in the next generation design. Some of these technologies have been developed in support of existing plants and near term designs while others will need to be developed and tested. This paper will discuss the key principles driving the next generation CANDU design and the fuel cycle flexibility of the CANDU system which provide synergism with the PWR fuel cycle. (author)

Flexibility@Work 2013: yearly report on flexible labor and employment

NARCIS (Netherlands)

Berkhout, E.; Heyma, A.; Prins, J.

2013-01-01

There is no clear evidence that the strong growth in the share of flexible labor relations between 2002 and 2007 points at a worldwide trend towards a larger share of flexible labor at the expense of traditional open-ended labor contracts. The growth in flexible labor varies too much between

Highly Flexible and Washable Nonwoven Photothermal Cloth for Efficient and Practical Solar Steam Generation

KAUST Repository

Jin, Yong; Chang, Jian; Shi, Yusuf; Shi, Le; Hong, Seunghyun; Wang, Peng

2018-01-01

-photothermal-component-loss property and is highly flexible and mechanically strong, chemically stable in various harsh environment such as strong acid, alkaline, organic solvent and salty water. It can be hand-washed for more than 100 times without degrading its performance and thus

Valuing flexibilities in the design of urban water management systems.

Science.gov (United States)

Deng, Yinghan; Cardin, Michel-Alexandre; Babovic, Vladan; Santhanakrishnan, Deepak; Schmitter, Petra; Meshgi, Ali

2013-12-15

Climate change and rapid urbanization requires decision-makers to develop a long-term forward assessment on sustainable urban water management projects. This is further complicated by the difficulties of assessing sustainable designs and various design scenarios from an economic standpoint. A conventional valuation approach for urban water management projects, like Discounted Cash Flow (DCF) analysis, fails to incorporate uncertainties, such as amount of rainfall, unit cost of water, and other uncertainties associated with future changes in technological domains. Such approach also fails to include the value of flexibility, which enables managers to adapt and reconfigure systems over time as uncertainty unfolds. This work describes an integrated framework to value investments in urban water management systems under uncertainty. It also extends the conventional DCF analysis through explicit considerations of flexibility in systems design and management. The approach incorporates flexibility as intelligent decision-making mechanisms that enable systems to avoid future downside risks and increase opportunities for upside gains over a range of possible futures. A water catchment area in Singapore was chosen to assess the value of a flexible extension of standard drainage canals and a flexible deployment of a novel water catchment technology based on green roofs and porous pavements. Results show that integrating uncertainty and flexibility explicitly into the decision-making process can reduce initial capital expenditure, improve value for investment, and enable decision-makers to learn more about system requirements during the lifetime of the project. Copyright © 2013 Elsevier Ltd. All rights reserved.

Power unit-cargo space link in transport

Directory of Open Access Journals (Sweden)

Radmilović Zoran R.

2005-01-01

Full Text Available This paper deals with transportation technology regarding links between power unit and cargo space. These links can be divided into two groups: rigid and flexible. Rigid link, established between power unit and cargo space, is dominant in maritime and road transport (sea ships and trucks, and occasionally in transport on inland waterways (self- propelled barges. Flexible link is used in the railroad transport (systems with trailers and semi trailers, and in inland waterway transport (push - towing and pulling systems, and combinations of the systems. The main goal of this research is determination of possible link types and organization of the means of transportation.

Demand-Side Flexibility for Energy Transitions: Policy Recommendations for Developing Demand Response

OpenAIRE

Nursimulu, Anjali; Florin, Marie-Valentine; Vuille, François

2016-01-01

As a follow-up to IRGC's report on demand-side flexibility for energy transitions, this Policy Brief highlights that increasing flexibility in power systems is needed to accommodate higher shares of non-controllable and intermittent renewable generation, and that this requires changes to the market design and regulatory framework, to facilitate the development and deployment of appropriate technologies and market-based instruments (e.g. taxes and subsidies). The Policy Brief focuses on demand...

Generation and Propagation of Finite-Amplitude Waves in Flexible Tubes (A)

DEFF Research Database (Denmark)

Jensen, Leif Bjørnø

1972-01-01

Highly reproducible finite-amplitude waves, generated by a modified electromagnetic plane-wave generator, characterized by a rise time......Highly reproducible finite-amplitude waves, generated by a modified electromagnetic plane-wave generator, characterized by a rise time...

Impact of Flexibility Options on Grid Economic Carrying Capacity of Solar and Wind: Three Case Studies

Energy Technology Data Exchange (ETDEWEB)

Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Novacheck, Joshua [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); O' Connell, Matthew [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-12-01

In this study, we attempt to quantify the benefits of various options of grid flexibility by measuring their impact on two measures: economic carrying capacity and system costs. Flexibility can increase economic carrying capacity and reduce overall system costs. In some cases, options that provide a limited increase in economic carrying capacity can provide significant operational savings, thus demonstrating the need to evaluate flexibility options using multiple metrics. The value of flexibility options varies regionally due to different generation mixes and types of renewables. The more rapid decline in PV value compared to wind makes PV more dependent on adding flexibility options, including transmission and energy storage.

Large hydropower generating units

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-07-01

This document presents the Brazilian experience with the design, fabrication, construction, commissioning and operation of large scale and generation capacity unities. The experience had been acquired with the implementation of Itumbiara, Paulo Afonso IV, Tucurui, Itaipu and Xingo power plants, which are among the largest world unities.

IR Sensor Synchronizing Active Shutter Glasses for 3D HDTV with Flexible Liquid Crystal Lenses

Directory of Open Access Journals (Sweden)

Jeong In Han

2013-12-01

Full Text Available IR sensor synchronizing active shutter glasses for three-dimensional high definition television (3D HDTV were developed using a flexible liquid crystal (FLC lens. The FLC lens was made on a polycarbonate (PC substrate using conventional liquid crystal display (LCD processes. The flexible liquid crystal lens displayed a maximum transmission of 32% and total response time of 2.56 ms. The transmittance, the contrast ratio and the response time of the flexible liquid crystal lens were superior to those of glass liquid crystal lenses. Microcontroller unit and drivers were developed as part of a reception module with power supply for the IR sensor synchronizing active shutter glasses with the flexible liquid crystal lens prototypes. IR sensor synchronizing active shutter glasses for 3D HDTV with flexible liquid crystal lenses produced excellent 3D images viewing characteristics.

A Probability Analysis of the Generating Cost for EU-APR1400 Single Unit

International Nuclear Information System (INIS)

Ha, Gak Hyeon; Kim, Sung Hwan

2014-01-01

The nuclear power plant market is expected to grow rapidly in order to address issues of global warming, reducing CO 2 emissions and securing stable electricity supplies. Under these circumstances, the main primary goal of the EU-APR100 development is to ensure export competitiveness in the European countries. To this end, EU-APR1400 have been developed based one te APR1400 (Advanced Power Reactor, GEN Type) The EU-APR1400 adds many advanced design features to its predecessor, as outlined below in Table 1. In this simulation, the results of the generating cost of the EU-APR1400 single unit were determined using the probability cost analysis technique, the generating cost range was shown to be 56.16 ∼ 70.92 won/kWh.

A Probability Analysis of the Generating Cost for EU-APR1400 Single Unit

Energy Technology Data Exchange (ETDEWEB)

Ha, Gak Hyeon; Kim, Sung Hwan [KHNP CRI, Seoul (Korea, Republic of)

2014-10-15

The nuclear power plant market is expected to grow rapidly in order to address issues of global warming, reducing CO{sub 2} emissions and securing stable electricity supplies. Under these circumstances, the main primary goal of the EU-APR100 development is to ensure export competitiveness in the European countries. To this end, EU-APR1400 have been developed based one te APR1400 (Advanced Power Reactor, GEN Type) The EU-APR1400 adds many advanced design features to its predecessor, as outlined below in Table 1. In this simulation, the results of the generating cost of the EU-APR1400 single unit were determined using the probability cost analysis technique, the generating cost range was shown to be 56.16 ∼ 70.92 won/kWh.

Offering Strategy of a Flexibility Aggregator in a Balancing Market Using Asymmetric Block Offers

DEFF Research Database (Denmark)

Bobo, Lucien Ali; Delikaraoglou, Stefanos; Vespermann, Niklas

2018-01-01

scenarios are used to find optimal load-shifting offers under uncertainty. The problem is formulated as a stochastic mixed-integer linear program and can be solved with reasonable computational time. This work is taking place in the framework of the real-life demonstration project EcoGrid 2.0, which......In order to enable large-scale penetration of renewables with variable generation, new sources of flexibility have to be exploited in the power systems. Allowing asymmetric block offers (including response and rebound blocks) in balancing markets can facilitate the participation of flexibility...... aggregators and unlock load-shifting flexibility from, e.g., thermostatic loads. In this paper, we formulate an optimal offering strategy for a risk-averse flexibility aggregator participating in such a market. Using a price-taker approach, load flexibility characteristics and balancing market price forecast...

ACO-Initialized Wavelet Neural Network for Vibration Fault Diagnosis of Hydroturbine Generating Unit

OpenAIRE

Xiao, Zhihuai; He, Xinying; Fu, Xiangqian; Malik, O. P.

2015-01-01

Considering the drawbacks of traditional wavelet neural network, such as low convergence speed and high sensitivity to initial parameters, an ant colony optimization- (ACO-) initialized wavelet neural network is proposed in this paper for vibration fault diagnosis of a hydroturbine generating unit. In this method, parameters of the wavelet neural network are initialized by the ACO algorithm, and then the wavelet neural network is trained by the gradient descent algorithm. Amplitudes of the fr...

MAFsnp: A Multi-Sample Accurate and Flexible SNP Caller Using Next-Generation Sequencing Data

Science.gov (United States)

Hu, Jiyuan; Li, Tengfei; Xiu, Zidi; Zhang, Hong

2015-01-01

Most existing statistical methods developed for calling single nucleotide polymorphisms (SNPs) using next-generation sequencing (NGS) data are based on Bayesian frameworks, and there does not exist any SNP caller that produces p-values for calling SNPs in a frequentist framework. To fill in this gap, we develop a new method MAFsnp, a Multiple-sample based Accurate and Flexible algorithm for calling SNPs with NGS data. MAFsnp is based on an estimated likelihood ratio test (eLRT) statistic. In practical situation, the involved parameter is very close to the boundary of the parametric space, so the standard large sample property is not suitable to evaluate the finite-sample distribution of the eLRT statistic. Observing that the distribution of the test statistic is a mixture of zero and a continuous part, we propose to model the test statistic with a novel two-parameter mixture distribution. Once the parameters in the mixture distribution are estimated, p-values can be easily calculated for detecting SNPs, and the multiple-testing corrected p-values can be used to control false discovery rate (FDR) at any pre-specified level. With simulated data, MAFsnp is shown to have much better control of FDR than the existing SNP callers. Through the application to two real datasets, MAFsnp is also shown to outperform the existing SNP callers in terms of calling accuracy. An R package “MAFsnp” implementing the new SNP caller is freely available at http://homepage.fudan.edu.cn/zhangh/softwares/. PMID:26309201

78 FR 79709 - Duke Energy Florida, Inc., Crystal River Unit 3 Nuclear Generating Plant Post-Shutdown...

Science.gov (United States)

2013-12-31

... NUCLEAR REGULATORY COMMISSION [Docket No. 50-302; NRC-2013-0283] Duke Energy Florida, Inc., Crystal River Unit 3 Nuclear Generating Plant Post-Shutdown Decommissioning Activities Report AGENCY: Nuclear Regulatory Commission (NRC). ACTION: Notice of receipt; availability; public meeting; and request...

Aggregation model for curtailable generation and sheddable loads

DEFF Research Database (Denmark)

Marthinsen, Håkon; Morch, Andrei Z.; Plećaš, Milana

2017-01-01

This study shows modelling developed during the first year of the SmartNet project. In particular, it presents a mathematical model for aggregation of curtailable generation and sheddable loads. The model determines the quantity and the cost of the flexibility provided by the flexible resources...

Review of the research proposal for the steam generator retired from Kori unit 1

Energy Technology Data Exchange (ETDEWEB)

Kim, Joung Soo; Han, Joung Ho; Kim, Hong Pyo; Lim, Yun Soo; Lee, Deok Hyun; Hwang, Seong Sik; Hur, Do Haeng [Korea Atomic Energy Research Institute, Taejeon (Korea)

2002-03-01

The tubes of the steam generator retired form Kori unit 1 have many different kinds of failures, such as denting pitting, wastage, ODSCC, PWSCC.Korea Electric Power Research Institute (KEPRI) submitted a research proposal for the steam generator to the Korea Institute S and T Evaluation and Planning (KSITEP). The KISTEP requested Korea Atomic Energy Research Institute to review the proposal by organizing a committee which should be composed of the specialists of the related domestic research institutes. Opinions of the committee on the objectives, research fields, economic benefit and validity in the research proposal were reviewed and suggested optimal research fields to be fulfilled successfully for the retired steam generator. Also, the rolls for the participants in the research works were allocated, which is critical in order to do the project effectively. 6 figs., 5 tabs. (Author)

Dynamic analysis of hybrid energy systems under flexible operation and variable renewable generation – Part II: Dynamic cost analysis

International Nuclear Information System (INIS)

Garcia, Humberto E.; Mohanty, Amit; Lin, Wen-Chiao; Cherry, Robert S.

2013-01-01

Dynamic analysis of HES (hybrid energy systems) under flexible operation and variable renewable generation is considered in this two-part communication to better understand various challenges and opportunities associated with the high system variability arising from the integration of renewable energy into the power grid. Advanced HES solutions are investigated in which multiple forms of energy commodities, such as electricity and chemical products, may be exchanged. In particular, a comparative dynamic cost analysis is conducted in this part two of the communication to determine best HES options. The cost function includes a set of metrics for computing fixed costs, such as fixed operations and maintenance and overnight capital costs, and also variable operational costs, such as cost of operational variability, variable operations and maintenance cost, and cost of environmental impact, together with revenues. Assuming natural gas, coal, and nuclear as primary heat sources, preliminary results identify the level of renewable penetration at which a given advanced HES option (e.g., a nuclear hybrid) becomes increasingly more economical than a traditional electricity-only generation solution. Conditions are also revealed under which carbon resources may be better utilized as carbon sources for chemical production rather than as combustion material for electricity generation. - Highlights: ► Dynamic analysis of HES to investigate challenges related to renewable penetration. ► Evaluation of dynamic synergies among HES constituents on system performance. ► Comparison of traditional versus advanced HES candidates. ► Dynamic cost analysis of HES candidates to investigate their economic viability. ► Identification of conditions under which an energy commodity may be best utilized

Flexible Pb(Zr0.52Ti0.48)O3 Films for a Hybrid Piezoelectric-Pyroelectric Nanogenerator under Harsh Environments.

Science.gov (United States)

Ko, Young Joon; Kim, Dong Yeong; Won, Sung Sik; Ahn, Chang Won; Kim, Ill Won; Kingon, Angus I; Kim, Seung-Hyun; Ko, Jae-Hyeon; Jung, Jong Hoon

2016-03-01

In spite of extremely high piezoelectric and pyroelectric coefficients, there are few reports on flexible ferroelectric perovskite film based nanogenerators (NGs). Here, we report the successful growth of a flexible Pb(Zr0.52Ti0.48)O3 (PZT) film and its application to hybrid piezoelectric-pyroelectric NG. A highly flexible Ni-Cr metal foil substrate with a conductive LaNiO3 bottom electrode enables the growth of flexible PZT film having high piezoelectric (140 pC/N) and pyroelectric (50 nC/cm(2)K) coefficients at room temperature. The flexible PZT-based NG effectively scavenges mechanical vibration and thermal fluctuation from sources ranging from the human body to the surroundings such as wind. Furthermore, it stably generates electric current even at elevated temperatures of 100 °C, relative humidity of 70%, and pH of 13 by virtue of its high Curie temperature and strong resistance for water and base. As proof of power generation under harsh environments, we demonstrate the generation of extremely high current at the exhaust pipe of a car, where hot CO and CO2 gases are rapidly expelled to air. This work expands the application of flexible PZT film-based NG for the scavenging mechanical vibration and thermal fluctuation energies even at extreme conditions.

Development of Hybrid Type Flexible Pneumatic Cylinder for Considering Less Air Consumption

Directory of Open Access Journals (Sweden)

Tamaki Hiroaki

2016-01-01

Full Text Available Inexpensive rehabilitation devices that can be used at home are required because of a lack of PT and welfare workers. In the previous study, the low-cost portable rehabilitation device using a flexible spherical actuator that consists of flexible pneumatic cylinder was proposed and tested. However, a compact and high power compressor that supplies air pressure to pneumatic actuator has not been developed yet. In particular, the heat generated by compressing air prevents to miniaturize it. To realize a home rehabilitation, the small-sized compressors or less air consuming flexible actuators are required. In this study, a hybrid type flexible pneumatic cylinder driven by electric motors and air pressure is proposed and tested. The concept, the construction and the operating principle of the proposed actuator were described. The position control using the tested actuator is also carried out.

Operation time extension for power units of the first generation NPP and the liability for potential damage

International Nuclear Information System (INIS)

Kovalevich, O.M.

2000-01-01

The problem on the operation time extension for the six operating NPP first generation power units is discussed. However it is not advisable to improve the safety of these power units up to the acceptable level, therefore there arises the contradiction between the operation time extension of these power units and potential damage for the population. The possibility of having the increased civilian-legal responsibility for potential harm and losses in case of an accident is proposed to be considered as a compensating measure. The measures for realization of this civilian-legal responsibility are described [ru

Flexible joints in structural and multibody dynamics

Directory of Open Access Journals (Sweden)

O. A. Bauchau

2013-02-01

Full Text Available Flexible joints, sometimes called bushing elements or force elements, are found in all structural and multibody dynamics codes. In their simplest form, flexible joints simply consist of sets of three linear and three torsional springs placed between two nodes of the model. For infinitesimal deformations, the selection of the lumped spring constants is an easy task, which can be based on a numerical simulation of the joint or on experimental measurements. If the joint undergoes finite deformations, identification of its stiffness characteristics is not so simple, specially if the joint is itself a complex system. When finite deformations occur, the definition of deformation measures becomes a critical issue. This paper proposes a family of tensorial deformation measures suitable for elastic bodies of finite dimension. These families are generated by two parameters that can be used to modify the constitutive behavior of the joint, while maintaining the tensorial nature of the deformation measures. Numerical results demonstrate the objectivity of the deformations measures, a feature that is not shared by the deformations measures presently used in the literature. The impact of the choice of the two parameters on the constitutive behavior of the flexible joint is also investigated.

Development of radiation protection technology for application of the retired steam generator, Kori Unit no. 1

Energy Technology Data Exchange (ETDEWEB)

Kim, J. H.; Jang, D. C.; Song, K. S.; Lee, S. J.; Ahn, C. S.; Kim, D. H.; Im, Y. K.; Kim, H. D. [Hanil Nuclear Co., Ltd., Anyang (Korea, Republic of)

2005-04-15

It is a field study to develop and verify maintenance technologies such as verification and technology development of ECT (Eddy current test) using failure, heat tube excavation and field pressure test regarding the utilization of retired steam generator using 2 units of Retired Steam Generator in Kori 1 that was replaced for the first time in Korea in 1998. Since May, 2003, our team has investigated Retired Steam Generator which was stored in Radioactive waste warehouse in Korea Hydro and Nuclear Power Kori unit no.1 Branch, in order to study natural fault ECT signal acquisition, maintenance technology verification, small tubes/samples abstraction. A temporal task zone was made focusing on 'Man Way at the bottom of Chamber 'A'.' The purpose of the study is to establish Radiological Protection and Radioactive Waste Treatment Plan by setting ALARA (As Low As Reasonably Achievable) goal systematically, which is the basic concept of Radiological Protection and reduction in exposure of radiological workers to radioactive materials with proper Radiological Protection countermeasures according to the changes in radioactivity, to prevent expansion from contamination and to manage 'Radioactive Waste Reduction Activities' effectively.

Size matters: Installed maximal unit size predicts market life cycles of electricity generation technologies and systems

International Nuclear Information System (INIS)

Li, N.

2008-01-01

The electricity generation technologies and systems are complex and change in very dynamic fashions, with a multitude of energy sources and prime movers. Since an important concept in generator design is the 'economies of scale', we discover that the installed maximal unit size (capacity) of the generators is a key 'envelope-pushing' characteristic with logistical behaviors. The logistical wavelet analysis of the max unit sizes for different fuels and prime movers, and the cumulative capacities, reveals universal quantitative features in the aggregate evolution of the power industry. We extract the transition times of the max sizes (spanning 10-90% of the saturation limits) for different technologies and systems, and discover that the max size saturation in the 90-99% range precedes the saturation of cumulative capacities of the corresponding systems in the US. While these universal laws are still empirical, they give us a simple yet elegant framework to examine the evolution of the power industry and markets in predictive, not just descriptive, terms. Such laws give us a quantitative tool to spot trends and predict future development, invaluable in planning and resource allocation based on intrinsic technology and system market life cycles

Dynamic Model of a Rotating Flexible Arm-Flexible Root Mechanism Driven by a Shaft Flexible in Torsion

Directory of Open Access Journals (Sweden)

S.Z. Ismail

2006-01-01

Full Text Available This paper presents a dynamic model of a rotating flexible beam carrying a payload at its tip. The model accounts for the driving shaft and the arm root flexibilities. The finite element method and the Lagrangian dynamics are used in deriving the equations of motion with the small deformation theory assumptions and the Euler-Bernoulli beam theory. The obtained model is a nonlinear-coupled system of differential equations. The model is simulated for different combinations of shaft and root flexibilities and arm properties. The simulation results showed that the root flexibility is an important factor that should be considered in association with the arm and shaft flexibilities, as its dynamics influence the motor motion. Moreover, the effect of system non-linearity on the dynamic behavior is investigated by simulating the equivalent linearized system and it was found to be an important factor that should be considered, particularly when designing a control strategy for practical implementation.

78 FR 14361 - In the Matter of Luminant Generation Company LLC, Comanche Peak Nuclear Power Plant, Units 1 and...

Science.gov (United States)

2013-03-05

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0310; Docket Nos. 50-445 and 50-446; License Nos. NPF-87 and NPF-89] In the Matter of Luminant Generation Company LLC, Comanche Peak Nuclear Power Plant, Units... Nuclear Power Plant, Units 1 and 2 (CPNPP), and its Independent Spent Fuel Storage Installation Facility...

Development and field tests of a damping controller to mitigate electromechanical oscillations on large diesel generating units

Energy Technology Data Exchange (ETDEWEB)

Nogueira, Fabricio G.; Barreiros, Jose A.L.; Barra, Walter Jr.; Costa, Carlos T. Jr. [Universidade Federal do Para (UFPA), Instituto de Tecnologia, Faculdade de Engenharia Eletrica, Campus Universitario do Guama, CEP: 66075-900, Belem (Brazil); Ferreira, Andre M.D. [Instituto Federal de Educacao, Ciencia e Tecnologia do Para (IFPA), Campus Belem, Departamento de Controle e Processos Industriais, Av. Almirante Barroso, 1155 (Marco), CEP: 66093-020, Belem (Brazil)

2011-02-15

This paper presents the development and field tests of a digital damping controller designed to mitigate intra-plant electromechanical oscillations via the speed governor system of fast acting units. The controller performance is assessed on an 18-MVA diesel generating unit, at Santana Power Plant (Amapa State, Amazon Region at Northern Brazil). In order to design the damping control law, a set of parametric ARX models representing the plant dynamics at several load conditions, are previously identified from data collected on field tests. The damping controller gains are calculated by using the identified ARX models parameters as inputs to a discrete-time pole-placement design method (pole-shifting) and then embedded on a DSP based microcontroller digital system, for field tests assessment. The digital damping controller modulates the diesel engine inlet valve position according to the observed oscillation on the measured electric power, using a PWM device, which is specially developed to this application. The experimental results shown the good performance of the developed controller on damping efficiently the electromechanical oscillations observed between generating units at Santana Power Plant. (author)

Efficiency of Executive Function: A Two-Generation Cross-Cultural Comparison of Samples From Hong Kong and the United Kingdom.

Science.gov (United States)

Ellefson, Michelle R; Ng, Florrie Fei-Yin; Wang, Qian; Hughes, Claire

2017-05-01

Although Asian preschoolers acquire executive functions (EFs) earlier than their Western counterparts, little is known about whether this advantage persists into later childhood and adulthood. To address this gap, in the current study we gave four computerized EF tasks (providing measures of inhibition, working memory, cognitive flexibility, and planning) to a large sample ( n = 1,427) of 9- to 16-year-olds and their parents. All participants lived in either the United Kingdom or Hong Kong. Our findings highlight the importance of combining developmental and cultural perspectives and show both similarities and contrasts across sites. Specifically, adults' EF performance did not differ between the two sites; age-related changes in executive function for both the children and the parents appeared to be culturally invariant, as did a modest intergenerational correlation. In contrast, school-age children and young adolescents in Hong Kong outperformed their United Kingdom counterparts on all four EF tasks, a difference consistent with previous findings from preschool children.